Preheating Device

Abstract

A preheating device 21 of one embodiment of the present invention is a device for preheating a molding material Mm, wherein the preheating device 21 has a material feed passage 22 through which the molding material Mm passes and a heater 24 for heating the molding material Mm passing through the material feed passage 22, the material feed passage 22 has paired passage-forming members 23 arranged facing each other that demarcate the material feed passage 22 between the two, at least one of the paired passage-forming members 23 is mobile, and the device is configured so that the passage width between the passage-forming members 23 is adjustable. Also, an injection device 1 of one embodiment of the present invention is equipped with the preheating device 21 and a cylinder 11 for melting the molding material Mm preheated by the preheating device 21 and is a device that injects the molding material Mm melted by the cylinder 11 into a mold device.

Description

[Technical field]

[0001] The present invention relates to a preheating device and an injection device. [Background technology]

[0002] For example, when manufacturing molded products such as PET bottle caps, injection molding machines are sometimes used in high-cycle molding, which involves repeatedly performing a series of steps in a relatively short cycle, from melting resin pellets or other molding materials and injecting them into a mold device to obtaining a molded product. In such cases, the injection molding machine is required to have a high production capacity.

[0003] The molding cycle of an injection molding machine can be shortened by increasing the rotation speed of the screw placed inside the cylinder of the injection device to complete the plasticization of the molding material in a short period of time, thereby shortening the time required for the molding material to accumulate at the tip of the cylinder.

[0004] However, when the screw rotates at high speed, the molding material is not sufficiently heated by the heater provided around the cylinder inside the cylinder, and is rapidly sent to the tip of the cylinder. In this case, the molten molding material injected from the tip of the cylinder into the mold device may contain unmelted molding material, which may cause defects such as poor appearance and reduced strength of the molded product. It is possible to promote the plasticization of the molding material by increasing the heating temperature by the heater around the cylinder, but in high-cycle molding, the residence time of the molding material inside the cylinder is short, so even if the heating temperature is increased, the injection of the unmelted molding material as described above cannot be sufficiently prevented.

[0005] To deal with this problem, it may be considered to preheat the molding material before supplying it into the cylinder.

[0006] In addition, Patent Document 1 proposes an injection molding apparatus for long fiber reinforced thermoplastic resin, which is characterized by comprising a plasticizer that melts and plasticizes pellets of long fiber reinforced thermoplastic resin by a planar heater moving toward the outlet side, an extruder that extrudes the molten resin from the outlet of the plasticizer, and a plunger-type injector that introduces and injects the resin from the extruder, for the purpose of "providing an injection molding apparatus that can minimize damage to the fibers even when melting pellet-shaped long fiber reinforced thermoplastic resin, and can melt the resin while defibrating the fiber bundles in the pellets while maintaining the fiber length, and molds high-strength fiber reinforced thermoplastic resin." Specifically, it is described that "the planar heater is a combination of multiple heating rolls," "the planar heater is a combination of a heating roll and a heating belt," "the planar heater is a combination of two heating belts," etc. (see Figures 1 to 4 of Patent Document 1). According to the "Injection Molding Apparatus for Long Fiber Reinforced Thermoplastic Resin" described in Patent Document 1, "When pellets of long fiber reinforced thermoplastic resin are supplied to the surface of a planar heating body, the pellets roll on the surface of the planar heating body so that the longitudinal axis of the pellets gradually becomes parallel to the surface of the planar heating body. In this state, the pellets are pressed against the surface and, as the planar heating body moves toward the outlet, are melted and sent to the outlet of the plasticizing device. The molten resin is then extruded by the extruder into the injection cylinder of the injector, and the resin in the injection cylinder is injected into a mold by the plunger. Therefore, the pellets are not kneaded in the plasticizing device, extruder, and injector, and the resin can be melted while defibrating the pellets while maintaining the fiber length, making it possible to mold a high-strength fiber reinforced thermoplastic resin."

[0007] Patent document 2 describes "a hopper for an injection molding machine that supplies molding material into the heating cylinder of an injection molding machine, characterized in that a dehumidifying temperature control device that is connected to the inside of the hopper is attached to the outside of the hopper."

[0008] Patent Document 3 discloses an injection molding system including: "an injection molding machine for supplying undried resin pellets into the cylinder of an injection molding machine to perform the first injection, and then inspecting the quality of the resin purge injected after a predetermined time has elapsed since the first injection to perform injection with an optimal deposition amount per unit shot obtained by: a pellet supply path body for supplying pellets into the cylinder of the injection molding machine; a gas exhaust path body for exhausting moisture, gas, etc. in the resin discharged in the injection molding machine and / or the mold; and a pressure reducing device connected to the exhaust path body." With regard to this "injection molding system," Patent Document 3 states that "the injection molding system further includes a heating device for heating the pellets to be supplied to the injection molding machine," "the heating device is a heat exchanger that utilizes warm gas discharged from the injection molding machine," "the heating device is provided in the pellet supply path body," and "preferably, the heating device includes first and second heating devices. The second heating device is provided in the pellet supply path body on the injection molding machine side." More specifically, it is stated that "the pellet heating device 68 is a heat exchanger. Warm air from the injection molding machine is transported to the heat exchanger. Meanwhile, atmospheric air is transported to the heat exchanger via a compressor (not shown). Thus, the atmospheric air is heated to approximately 80°C as it passes through the heat exchanger. The warm air is then supplied to the pellet storage tank 12."

[0009] Patent Document 4 describes a molding method for a long fiber composite material, which is a composite material of long fibers for reinforcement and a thermoplastic resin, by using a counter-rotating twin-screw type extruder to plasticize the long fiber composite material, which is a composite material of long fibers for reinforcement and a thermoplastic resin, and feeding the plasticized material to a plunger type extruder, and injecting the plasticized material from the plunger type extruder into an injection compression molding die or extruding the plasticized material from the plunger type extruder into an extrusion die, and states that the long fiber composite material fed to the twin-screw type extruder is heated to a softened state by passing a high-temperature inert gas through it. Patent Document 4 also describes the high-temperature inert gas as follows: "The high-temperature inert gas circulation device 18 is a device in which an exhaust gas treatment device 21, a blower 22, and a heater 23 are connected in series, and a nitrogen gas cylinder 24 is connected upstream of the blower 22, and the long fiber pellets or bulk-like long fiber composite material 15 is heated to a softened state using high-temperature nitrogen gas as a heat medium." [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Application Publication No. 8-142139 [Patent Document 2] Japanese Utility Model Application Publication No. 62-104915 [Patent Document 3] WO 99 / 33630 [Patent Document 4] Japanese Patent Application Publication No. 7-52185 Summary of the Invention [Problem to be solved by the invention]

[0011] Here, the conventional techniques described in the above-mentioned documents cannot be said to be techniques that sufficiently contribute to improving the production capacity of molded products, and there is a demand for techniques that can effectively preheat the molding material before it is supplied into the cylinder of the injection device.

[0012] Specifically, when preheating molding materials before supplying them to the inside of the cylinder, particularly in high-cycle molding, it is effective to narrow the width of the passage through which a large number of molding materials pass during preheating to some extent in order to efficiently heat the molding materials in a short time. This allows the molding materials to pass through the passage while, for example, lining up in a line, and at that time, most of the molding materials are likely to be directly heated by heaters on both sides of the passage. However, molding materials such as resin pellets come in a variety of sizes and shapes, and it is difficult to set a passage width suitable for all of such a variety of molding materials.

[0013] Neither Patent Document 1 nor Patent Document 2 pays any attention to optimizing preheating in consideration of the dimensions and shape of such molding materials. Patent Document 1 describes how pellets are plasticized by being pressed and crushed in a plasticization device to obtain molten resin to be supplied to a plunger-type injector, but does not describe or suggest anything about preheating as described above. In Patent Document 2, as shown in Fig. 1, a dehumidifying temperature regulator is provided in a conical or other hopper that supplies molding material into the cylinder of an injection molding machine. In a conical or other hopper, multiple molding materials are irregularly placed one on top of the other, so the dehumidifying temperature regulator of such a hopper cannot heat multiple molding materials effectively enough.

[0014] The first invention has as its object to address such problems, and its objective is to provide a preheating device and an injection device that can effectively preheat the molding material before it is supplied into the cylinder.

[0015] However, the hopper described in the above Patent Document 2 also had the following problem. That is, the hopper described in Patent Document 2, as described above, is a conical hopper that supplies molding material into the cylinder of an injection molding machine, and a dehumidifying temperature regulator is provided in the hopper, as shown in FIG. 1. Although the hopper can preheat the molding material, there is room for improvement. That is, the injection device is required to efficiently heat molding material such as resin pellets in a short time, and further, to heat the molding material uniformly.

[0016] The second invention is aimed at addressing these problems, and its objective is to provide a preheating device and an injection device that can effectively preheat the molding material before it is supplied into the cylinder.

[0017] Here, the above Patent Documents 3 and 4 have the following problems. That is, the hot air obtained by heating air and the high-temperature inert gas such as high-temperature nitrogen gas as described in Patent Documents 3 and 4 do not have a high thermal energy. Therefore, even if such hot air or high-temperature inert gas is used as a heat medium for preheating the molding material before supplying it to the inside of the cylinder, it takes a certain amount of time to heat the molding material to a predetermined temperature. Therefore, with the above-mentioned heat medium, there is a concern that the molding material may not be preheated sufficiently, especially in high-cycle molding in which the molding material is quickly supplied into the cylinder.

[0018] The third invention has as its object to address such problems, and has as its objective to provide a preheating device and an injection device that can relatively rapidly raise the temperature of the molding material by preheating the molding material before it is supplied into the cylinder.

[0019] However, the above-mentioned Patent Document 1 also has the following problem. That is, in order to preheat the molding material before supplying it to the inside of the cylinder, it is possible to introduce the molding material into a passage through which the molding material passes (hereinafter also referred to as a material feed passage) in order to preheat the molding material, and then heat the molding material present therein. However, when injection molding is performed using an injection device, the injection device may stop for some reason, which may cause the molding material to stop moving in the material feed passage. If the movement of the molding material in the material feed passage stops, the residual heat continues to heat the molding material, which may cause the molding material to melt and fuse with each other or with the wall surface. If such fusion occurs, there is a risk that the molding material will not be able to pass through the material feed passage even if injection molding is resumed. Such a problem is not paid any attention to, for example, Patent Document 1, which discloses a conventional injection device.

[0020] The fourth invention has as its object to address such problems, and has as its objective to provide a preheating device and an injection device which can preheat the molding material before it is supplied to the inside of a cylinder, and which can prevent the molding material from being overheated and melting in the passage through which the molding material to be preheated passes during this process. [Means for solving the problem]

[0021] The first preheating device capable of solving the problems of the first invention described above is for preheating a molding material, and the preheating device has a material feed passage through which the molding material passes, and a heater for heating the molding material passing through the material feed passage, and the material feed passage has a pair of passage forming members arranged opposite each other to define the material feed passage between them, and at least one of the pair of passage forming members is movable and configured to adjust the passage width between the passage forming members.

[0022] A second preheating device capable of solving the problems of the second invention described above is for preheating a molding material, and the preheating device has a material feed passage through which the molding material passes, and the material feed passage has a junction where the molding material and a heating medium join, and an in-line mixing section that mixes the molding material and the heating medium joined at the junction and heats the molding material with the heating medium.

[0023] A third preheating device capable of solving the problems of the third invention described above is for preheating a molding material, and the preheating device has a material passage through which the molding material passes, and a superheated steam inlet for introducing superheated steam into the material passage to heat the molding material in the material passage.

[0024] A fourth preheating device capable of solving the problems of the fourth invention described above is for preheating a molding material, and the preheating device has a material feed passage through which the molding material passes, a heating section for heating the molding material passing through the material feed passage, and a cooling section for cooling the molding material passing through the material feed passage. Effect of the Invention

[0025] According to the above-mentioned first preheating device, the passage width between the passage forming members is configured to be adjustable, so that the molding material can be effectively preheated before being supplied to the inside of the cylinder of the injection device.

[0026] According to the above-mentioned second preheating device, it is possible to effectively preheat the molding material before it is supplied into the cylinder of the injection device.

[0027] According to the third preheating device, the temperature of the molding material can be relatively rapidly increased by preheating before being supplied to the inside of the cylinder of the injection device.

[0028] According to the fourth preheating device described above, the molding material can be preheated before being supplied into the cylinder of the injection device, and during this process, the molding material can be prevented from being excessively heated and melted in the passage through which the molding material to be preheated passes. [Brief description of the drawings]

[0029] [Figure 1] FIG. 2 is a cross-sectional view showing a preheating device and an injection device according to an embodiment of the first invention. [Diagram 2] 2 is an enlarged cross-sectional view showing the preheating device of FIG. 1 and its vicinity. [Diagram 3] 3 is a front view showing a specific example of a passage forming member of the preheating device of FIG. 2. [Figure 4] 3 is an enlarged perspective view showing a material feed passage and a passage forming member of the preheating device of FIG. 2. [Diagram 5] 3 is a perspective view showing an example of a retention prevention mechanism that can be provided in the preheating device of FIG. 2. FIG. [Figure 6] 3 is a perspective view showing another example of a retention prevention mechanism that can be provided in the preheating device of FIG. 2. FIG. [Figure 7] 3 is a perspective view showing another example of a retention prevention mechanism that can be provided in the preheating device of FIG. 2. FIG. [Figure 8] 3 is a perspective view showing another example of a retention prevention mechanism that can be provided in the preheating device of FIG. 2. FIG. [Figure 9] 3 is a perspective view showing another example of a retention prevention mechanism that can be provided in the preheating device of FIG. 2. FIG. [Figure 10] 3 is a perspective view showing another example of a retention prevention mechanism that can be provided in the preheating device of FIG. 2. FIG. [Figure 11] FIG. 4 is a cross-sectional view showing a preheating device according to another embodiment of the first invention. [Figure 12] FIG. 4 is a cross-sectional view showing a preheating device according to still another embodiment of the first invention. [Figure 13] 3 is a cross-sectional view and a graph showing the temperature of a molding material passing through a material feed passage of the preheating device of FIG. 2. [Figure 14]3 is a flowchart showing an example of control that can be performed using the preheating device of FIG. 2. [Figure 15] FIG. 11 is a cross-sectional view showing a preheating device and an injection device according to an embodiment of a second invention. [Figure 16] 16 is an enlarged cross-sectional view showing the preheating device of FIG. 15 and its vicinity. [Figure 17] 16 is an enlarged perspective view showing a mixer provided in the preheating device of FIG. 15. FIG. [Figure 18] 16 is an enlarged cross-sectional view showing a gas pump provided in the preheating device of FIG. 15. [Figure 19] FIG. 11 is an enlarged cross-sectional view showing a preheating device and its vicinity according to another embodiment of the second invention. [Figure 20] FIG. 11 is an enlarged cross-sectional view showing a preheating device and its vicinity according to still another embodiment of the second invention. [Figure 21] 17 is a flowchart showing an example of control that can be performed using the preheating device of FIG. 16. [Figure 22] FIG. 13 is a vertical cross-sectional view showing a preheating device and an injection device according to an embodiment of a third invention. [Diagram 23] 23 is an enlarged cross-sectional view showing the preheating device of FIG. 22 and its vicinity. [Figure 24] 24 is an enlarged cross-sectional view showing a part of the preheating device of FIG. 23. [Diagram 25] FIG. 11 is a cross-sectional view showing a part of a preheating device according to another embodiment of the third invention. [Figure 26] FIG. 11 is a cross-sectional view showing a part of a preheating device according to still another embodiment of the third invention. [Figure 27] FIG. 13 is a horizontal cross-sectional view showing a part of a preheating device according to still another embodiment of the third invention. [Figure 28] 24 is a front view showing a specific example of a passage forming member of the material feed passage of the preheating device of FIG. 23. [Figure 29] 24 is an enlarged perspective view showing the material feed passage and the passage forming member of the preheating device of FIG. 23. [Diagram 30]FIG. 24 is a perspective view showing an example of a retention prevention mechanism that can be provided in the preheating device of FIG. 23. [Diagram 31] FIG. 24 is a perspective view showing another example of a retention prevention mechanism that can be provided in the preheating device of FIG. 23. [Diagram 32] FIG. 24 is a perspective view showing another example of a retention prevention mechanism that can be provided in the preheating device of FIG. 23. [Diagram 33] FIG. 24 is a perspective view showing another example of a retention prevention mechanism that can be provided in the preheating device of FIG. 23. [Diagram 34] FIG. 24 is a perspective view showing another example of a retention prevention mechanism that can be provided in the preheating device of FIG. 23. [Diagram 35] FIG. 24 is a perspective view showing another example of a retention prevention mechanism that can be provided in the preheating device of FIG. 23. [Diagram 36] FIG. 11 is a cross-sectional view showing a preheating device and its vicinity according to still another embodiment of the third invention. [Figure 37] FIG. 11 is a cross-sectional view showing a preheating device and its vicinity according to still another embodiment of the third invention. [Figure 38] 24 is a cross-sectional view and a graph showing the temperature of a molding material passing through a material feed passage of the preheating device of FIG. 23. [Figure 39] 24 is a flowchart showing an example of control that can be performed using the preheating device of FIG. 23. [Diagram 40] FIG. 13 is a cross-sectional view showing a preheating device and an injection device according to a first embodiment of the fourth invention. [Diagram 41] 41 is an enlarged cross-sectional view showing the preheating device of FIG. 40 and its vicinity. [Diagram 42] FIG. 41 is a block diagram of a control device for the preheating device of FIG. 40. [Diagram 43] 42 is a cross-sectional view and a graph showing the temperature of a molding material passing through a material feed passage of the preheating device of FIG. 41. [Diagram 44] 42 is a flowchart showing an example of control that can be performed using the preheating device of FIG. 41. [Diagram 45] FIG. 57 is a front view showing a specific example of a passage forming member of the preheating device of FIGS. 41 and 56. [Diagram 46] FIG. 57 is an enlarged perspective view showing the material feed passage and the passage forming member of the preheating device of FIGS. 41 and 56. [Figure 47] FIG. 57 is a perspective view showing an example of a retention prevention mechanism that can be provided in the preheating device of FIGS. 41 and 56. [Figure 48] FIG. 57 is a perspective view showing another example of the retention prevention mechanism that can be provided in the preheating device of FIGS. 41 and 56. [Figure 49] FIG. 57 is a perspective view showing another example of the retention prevention mechanism that can be provided in the preheating device of FIGS. 41 and 56. [Figure 50] FIG. 57 is a perspective view showing another example of the retention prevention mechanism that can be provided in the preheating device of FIGS. 41 and 56. [Figure 51] FIG. 57 is a perspective view showing another example of the retention prevention mechanism that can be provided in the preheating device of FIGS. 41 and 56. [Figure 52] FIG. 57 is a perspective view showing another example of the retention prevention mechanism that can be provided in the preheating device of FIGS. 41 and 56. [Diagram 53] FIG. 4 is a cross-sectional view showing a preheating device according to a first modified example of the first embodiment. [Figure 54] FIG. 11 is a cross-sectional view showing a preheating device according to a second modified example of the first embodiment. [Figure 55] FIG. 13 is a vertical cross-sectional view showing a preheating device and an injection device according to a second embodiment of the fourth invention. [Figure 56] FIG. 56 is an enlarged cross-sectional view showing the preheating device of FIG. 55 and its vicinity. [Figure 57] FIG. 57 is an enlarged cross-sectional view showing a part of the preheating device of FIG. 56. [Figure 58] FIG. 11 is a cross-sectional view showing a part of a preheating device of a first modified example of the second embodiment. [Figure 59] FIG. 11 is a cross-sectional view showing a part of a preheating device of a second modified example of the second embodiment. [Figure 60] FIG. 11 is a horizontal cross-sectional view showing a part of a preheating device of a third modified example of the second embodiment. [Figure 61]FIG. 11 is a cross-sectional view showing a preheating device and its vicinity in a fourth modified example of the second embodiment. [Figure 62] FIG. 13 is a cross-sectional view showing a preheating device and its vicinity in a fifth modified example of the second embodiment. [Figure 63] FIG. 13 is a cross-sectional view showing a preheating device and an injection device according to a third embodiment of the fourth invention. [Figure 64] FIG. 64 is an enlarged cross-sectional view showing the preheating device of FIG. 63 and its vicinity. [Figure 65] FIG. 65 is an enlarged perspective view showing a mixer provided in the preheating device of FIG. 64. [Figure 66] FIG. 65 is an enlarged cross-sectional view showing a gas pump provided in the preheating device of FIG. 64. [Figure 67] FIG. 13 is an enlarged cross-sectional view showing a preheating device and its vicinity in a first modified example of the third embodiment. [Figure 68] FIG. 13 is an enlarged cross-sectional view showing a preheating device and its vicinity in a second modified example of the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0031] [First Invention] In this embodiment, the preheating device 21 is for preheating the molding material, and by being provided in the injection device 1 as illustrated in FIG. 1, the preheated molding material can be supplied to the injection device 1. The injection device 1 illustrated in FIG. 1 is an injection molding machine, and is disposed, for example, on a slide base 101 of a moving device that moves the injection device 1 forward and backward, and injects the molding material into a mold device. The injection device 1 can be provided with the preheating device 21 and a cylinder 11 to which the molding material preheated by the preheating device is supplied and melts the molding material inside. The illustrated injection device 1 further includes a screw 12 that is rotated and driven inside the cylinder 11 to plasticize the molding material, a heater 13 that is provided around the cylinder 11 to heat the molding material inside the cylinder 11, and the detailed structure of the injection device 1 will be described later.

[0032] (Preheating device) The preheating device 21 is attached to the rear end of the cylinder 11 on the opposite side to the tip end 14 that injects the molding material, in the direction of the rotation axis of the screw 12 of the injection device 1 (left and right direction in Fig. 1). More specifically, the preheating device 21 is connected to a through-hole-like supply port 11a provided on a part of the circumference of the rear end of the cylinder 11, as shown in Fig. 2, and supplies molding material Mm, such as resin pellets having substantially spherical or cylindrical shapes or other shapes, to the supply port 11a.

[0033] In this embodiment, the preheating device 21 has a material feed passage 22 through which the molding material Mm passes, and a heater 24 for heating the molding material Mm passing through the material feed passage 22. Here, the material feed passage 22 has a pair of passage forming members 23 arranged opposite each other to define the material feed passage 22 between them. The heater 24 is arranged outside the material feed passage 22 in the passage width direction separated by the passage forming member 23. The passage width direction here means the alignment direction of the passage forming members 23 arranged in parallel with each other, and means a direction (left and right direction in FIG. 2) perpendicular to the material passing direction (up and down direction in FIG. 2) in which the molding material Mm passes through the material feed passage 22. The material feed passage 22, the passage forming member 23, and the heater 24 are accommodated and arranged inside a box-shaped housing 25 made of a heat insulating material or the like.

[0034] In the preheating device 21 having such a configuration, the molding material Mm to be supplied into the cylinder 11 can be preheated before being supplied. As a result, the preheated molding material Mm is supplied into the cylinder 11 through the supply port 11a, and then sufficiently melted within a short time inside the cylinder 11 and injected from the tip of the cylinder 11, thereby realizing a shortened molding cycle.

[0035] 2, at least one of the pair of path forming members 23 that define the material feed path 22 is movable, so that the preheating device 21 is configured to be able to adjust the path width of the material feed path 22, which is the distance between the pair of path forming members 23. At least one of the path forming members 23 can be moved in the path width direction, for example, manually by a user placing a spacer between the path forming member 23 and its attachment point inside the housing 25, or automatically by using a motor or other actuator.

[0036] By making the passage width of the material feed passage 22 adjustable, it is possible to set an appropriate passage width according to each of the various molding materials Mm having various dimensions and shapes. For example, as shown in Fig. 2, when the passage width is set to a width that allows one piece of molding material Mm to pass through, the molding materials Mm pass through the material feed passage 22 in a substantially lined-up position, and at this time, most of the molding material Mm is effectively heated by the heater 24 on the outer side of the passage width direction of the passage forming member 23. This effectively prevents unmelted material from being mixed into the molten molding material injected from the tip of the cylinder 11, thereby preventing poor appearance and reduced strength of the molded product.

[0037] The passage width set by the movable passage forming member 23 is preferably equal to or greater than the length of one piece of molding material Mm and less than the length of two pieces of molding material Mm. In this case, since the overlapping of a plurality of molding materials Mm in the passage width direction in the material feed passage 22 is suppressed, many of the molding materials Mm can be heated more effectively. The length of one piece of molding material Mm is preferably set to the shortest dimension of the molding material Mm. For example, if the molding material Mm is substantially spherical, it is preferably set to its diameter, or if the molding material Mm is irregularly shaped, including an ellipse or oval in cross section, it is preferably set to the diameter of the shortest short side. Alternatively, if the molding material Mm is cylindrical, prismatic, or other columnar, the shorter of the diameter or the width and height may be set to the length of one piece of molding material Mm.

[0038] A supply container 26 (cylinder supply container 26, also simply called supply container 26) for supplying molding material to a cylinder such as a hopper is provided on the lower surface of the housing 25 at the tip end side (lower end side in FIG. 2) of the material passing direction of the material feed passage 22. In the illustrated example, the supply container 26 has a truncated cone-shaped portion 26a, the inner and outer shapes of which are both truncated cones, and a cylindrical portion 26b formed at the end of the truncated cone-shaped portion 26a on the small diameter side. The supply container 26 receives the molding material Mm that has passed through the material feed passage 22 in the truncated cone-shaped portion 26a, and then supplies the molding material Mm to the inside of the cylinder 11 through the cylindrical portion 26b at the end of the truncated cone-shaped portion 26a. An opening 26c having a width approximately the same as that of the material feed passage 22 is formed at the end of the truncated cone-shaped portion 26a, and the molding material Mm that has passed through the material feed passage 22 enters the supply container 26 from the opening 26c.

[0039] At the rear end side (upper end side in FIG. 2) of the material feed passage 22 in the material passing direction, a supply container 27 (supply container 27 for supplying passages, also simply referred to as supply container 27) for supplying molding material to a passage such as a hopper which stores a plurality of molding materials Mm and supplies the molding material Mm in an appropriate amount to the material feed passage 22 is placed on the upper surface of the housing 25. The supply container 27 has a tube portion 27a having a cylindrical shape or the like, and a tapered portion 27b provided on the material feed passage 22 side of the tube portion 27a and having a gradually decreasing inner and outer diameter.

[0040] In the illustrated example, the molding material Mm is supplied to the preheating device 21 from a supply container 27 for supplying the passage. The molding material Mm supplied to the preheating device 21 passes through the material feed passage 22 while being preheated, and is supplied to the inside of the cylinder 11 after passing through the supply container 26 for supplying the cylinder. That is, here, the molding material Mm preheated by the preheating device 21 is supplied to the inside of the cylinder 11. However, the shape of the supply container 26 and / or the supply container 27 is not limited to this, and can be appropriately changed, and the supply container 26 and / or the supply container 27 may be omitted. If the supply container 26 for supplying the cylinder is omitted, the housing of the preheating device is placed on the cylinder, and the tip side of the material feed passage in the material passing direction is directly connected to the supply port of the cylinder. In this case, the molding material preheated by the preheating device is supplied to the inside of the cylinder immediately after the preheating.

[0041] Here, the heater 24 can be disposed on only one side of the material feed passage 22, outside one of the passage forming members 23 in the passage width direction, but in this embodiment, the heater 24 is disposed on both sides of the material feed passage 22, outside each of the passage forming members 23 in the passage width direction. This allows the molding material Mm to be heated quickly by the heaters 24 on both sides, so that the molding material Mm can be effectively heated even if the passing speed of the molding material Mm through the material feed passage 22 is made relatively fast. The conditions of the heater 24, etc. are set so that the molding material Mm reaches a desired temperature at the tip end of the material feed passage 22 in the material passing direction.

[0042] The heater 24 may be of any heating type as long as it can heat the molding material Mm through the passage forming member 23. For example, a hot air heating type heater that supplies a heated gas such as high-temperature air, an electric heater such as a high-frequency dielectric heater, an infrared heating type heater such as a halogen lamp or a ceramic heater, a laser heating type heater, etc. can be used. When the heater 24 is an infrared heating type heater or a laser heating type heater, the passage forming member 23 can be made of a translucent or transparent material such as glass through which light or a laser can pass. The arrangement of the heater 24 is not limited to the example shown in the figure, and the heater 24 may be arranged outside the housing 25 and hot air may be flowed through the material feed passage 22.

[0043] The illustrated preheating device 21 has, as an example, a heater 24 including a hot air heater. Specifically, the hot air heater can be one that generates hot air by heating compressed air sent from a compressor with a sheathed heater or the like. The temperature of the hot air can be adjusted by changing the output of the sheathed heater.

[0044] In this case, the passage forming member 23 may have a plurality of ventilation holes penetrating the passage forming member 23 in the passage width direction in order to pass the heated gas sent from the hot air heater through the material feed passage 22. As a result, the heated gas from the heater 24 flows into the material feed passage 22 through the ventilation holes of the passage forming member 23, so that the molding material Mm in the material feed passage 22 can be heated by the heated gas.

[0045] Specifically, the passage forming member 23 may be a plate-like member in which a plurality of ventilation holes 23b are formed in a metal plate material 23a by press working, etc., as shown in Fig. 3(a), such as a so-called punched metal. In this case, by adjusting the processing mode, etc., a plurality of regularly arranged ventilation holes 23b can be formed in the plate material 23a.

[0046] Alternatively, as shown in FIG. 3(b), the passage forming member 23 may be a mesh member in which, for example, wires 23c are arranged in a lattice pattern, and a plurality of vent holes 23b are provided between the wires, each having a square or other polygonal shape when viewed from the front. If the thickness of such a mesh member is thin and the mesh member does not have the strength required to form the material feed passage 22 with the passage forming member 23, the mesh member and a reinforcing member may be overlapped to form the passage forming member 23. The reinforcing member may have various shapes, such as a honeycomb shape or a lattice shape, as long as it can pass the heated gas. For example, the mesh of the reinforcing member may be coarser than that of the mesh member. In the illustrated mesh member, a plurality of vent holes 23b are arranged in a regular line in the vertical direction (up and down direction in FIG. 3(b)) and the horizontal direction (left and right direction in FIG. 3(b)) when viewed from the front.

[0047] For example, when the material feed passage 22 is defined by a mesh-like passage forming member 23, as shown in Fig. 4, the multiple molding materials Mm spread out in the lateral direction of the passage forming member 23 and move in the material passing direction, which is the vertical direction of the passage forming member 23, as shown by the arrows in the figure. Note that between the pair of passage forming members 23, on each side of the material feed passage 22 in the lateral direction of the passage forming member 23, passage dividing members 22a, such as square rods, are arranged to divide the area of ​​the material feed passage 22 in the lateral direction of the passage forming member 23.

[0048] When the air holes 23b are evenly distributed and regularly arranged in a front view like the above-mentioned mesh-like or plate-like passage forming member 23, the heated gas from the heater 24, which is a hot air heater, can be fed evenly to the material feed passage 22 in the vertical and horizontal directions of the passage forming member 23. This allows the heated gas to be blown onto many of the multiple molding materials Mm passing through the material feed passage 22, and the molding materials Mm can be heated even more effectively.

[0049] In the embodiment shown in FIG. 2, as the plasticization by the screw 12 or the like inside the cylinder 11 of the injection device 1 progresses, the molding material Mm is supplied from the supply container 26 for supplying the cylinder to the inside of the cylinder 11. Accordingly, the molding material Mm in the supply container 27 for supplying the passage passes through the material feed passage 22, is heated by the heater 24, and then is input into the supply container 26 for supplying the cylinder. In this case, the speed of the molding material Mm passing through the material feed passage 22 may depend on the speed of plasticization of the molding material Mm inside the cylinder 11, but the passing speed of the molding material Mm can also be adjusted by changing the passage width as described above. In addition, in order to adjust the speed at which the molding material Mm passes through the material feed passage 22 and the degree of heating of the molding material Mm affected by it, a screw-shaped feeder or other supply adjuster for adjusting the supply of the molding material Mm from the material feed passage 22 to the supply container 26 may be provided between the material feed passage 22 and the supply container 26, although not shown in the figure. Although not shown, there may be a mechanism for changing the position of the material feed passage 22 while keeping the passage width constant. By changing the position of the material feed passage 22, the amount of molding material passing through per unit time can be adjusted.

[0050] Incidentally, in a mesh-like or plate-like passage forming member 23 having a plurality of ventilation holes 23b, the molding material Mm may get caught in the ventilation holes 23b in the material feed passage 22 formed thereby, causing the molding material Mm to become clogged or accumulate in at least a portion of the lateral direction of the passage forming member 23. The accumulation of the molding material Mm in the material feed passage 22 may lead to excessive heating of the molding material Mm, and ultimately to melting of the molding material Mm. Therefore, it is preferable to provide the preheating device 21 with a retention prevention mechanism for preventing retention of the molding material Mm in the material feed passage 22.

[0051] 5 to 8, the retention prevention mechanism can be a drive unit that displaces at least one of a pair of passage forming members 23 continuously during operation of the injection molding machine, or intermittently only when necessary, to change the relative position and / or orientation of one passage forming member 23 with respect to the other passage forming member 23. Note that illustration of the drive source is omitted here.

[0052] 5, square bar-shaped movable members 22b are provided on both lateral sides of one of the passage forming members 23, outside the passage width direction of the passage forming member 23. While the molding material Mm is passing through the material feed passage 22, the movable members 22b move one of the passage forming members 23 in the lateral direction of the passage forming member 23, as shown by the arrows in FIGS. 5(b) and 5(c), thereby changing the relative position of one of the passage forming members 23 with respect to the other passage forming member 23. As a result, even if the molding material Mm gets caught in the vent hole 23b, the movement of one of the passage forming members 23 releases the catch, preventing the molding material Mm from stagnation. Furthermore, one of the passage forming members 23 may be moved not in the lateral direction of the passage forming member 23 but in the vertical direction (up and down direction) parallel to the material passing direction.

[0053] In the retention prevention mechanism shown in Fig. 6, a square bar-shaped movable member 22b is provided on each of both vertical ends of one of the passage forming members 23, outside the passage width direction of the passage forming member 23. As shown in Figs. 6(b) and (c), this retention prevention mechanism moves one of the passage forming members 23 in the passage width direction by the movable member 22b, changing the relative position of one of the passage forming members 23 with respect to the other passage forming member 23, while the molding material Mm is passing through. At this time, the passage width of the material feed passage 22 increases and decreases slightly. The retention prevention mechanism in Fig. 6 can also be used as a mechanism for moving the passage forming member 23 to adjust the passage width as described above.

[0054] The retention prevention mechanism in Fig. 7 has a square rod-shaped movable member 22b provided on each of both ends of one of the passage forming members 23 in the vertical direction outside the passage width direction of the passage forming member 23, and a cylindrical or other fulcrum member 22c extending in the horizontal direction of the passage forming member 23, which is sandwiched between the passage forming member 23 and the passage dividing member 22a at an intermediate position such as the center position in the material passing direction of the material feed passage 22. Here, the fulcrum member 22c is attached to the passage dividing member 22a. In this case, as shown in Figs. 7(b) and (c), when the movable members 22b are moved in mutually opposite directions in the passage width direction, one of the passage forming members 23 is pivotally displaced around the fulcrum member 22c and changes its orientation so as to be oblique to the other passage forming member 23. More specifically, when one end of one passage forming member 23 in the vertical direction approaches or moves away from the other passage forming member 23, the orientation of one passage forming member 23 changes so that the other end of one passage forming member 23 in the vertical direction approaches or moves away from the other passage forming member 23. Accordingly, the passage width of the material feed passage 22 may not be constant in the material passing direction. Even with such a retention prevention mechanism, retention of the molding material Mm can be effectively prevented.

[0055] The retention prevention mechanism in Fig. 8 has a configuration similar to that in Fig. 7, but fulcrum member 22c is fixed and attached to one of the passage forming members 23, not to passage partition member 22a. In Fig. 8, by driving fulcrum member 22c to rotate without moving movable member 22b, one of the passage forming members 23 rotates and displaces around fulcrum member 22c together with fulcrum member 22c, and the orientation relative to the other passage forming member 23 changes in a manner substantially similar to that in Fig. 7.

[0056] Alternatively, as shown in Fig. 9(a), the retention prevention mechanism may be configured with an impact applying part 28 that is arranged on the outside of at least one of the passage forming members 23 in the passage width direction and strikes the passage forming member 23 at a predetermined period or the like. The illustrated impact applying part 28 includes a plate-shaped member 28b that is arranged parallel to the other passage forming member 23 on the outside of the other passage forming member 23 in the passage width direction and has one or more through holes 28a formed therein, and one or more pin-shaped members 28c that are arranged through the through holes 28a of the plate-shaped member 28b and displace toward or away from the other passage forming member 23. A similar impact applying part 28 may also be provided on the outside of one of the passage forming members 23 in the passage width direction.

[0057] In addition, the retention prevention mechanism may be configured as shown in Figure 9 (b) by a vibration imparting unit 29 such as one or more vibrators attached to at least one of the passage forming members 23, for example the outer surface in the passage width direction of the other passage forming member 23, and imparting vibrations to the passage forming member 23.

[0058] As shown in Fig. 10(a), the retention prevention mechanism may be a blower 30 that is disposed on at least one outer side of the passage width direction of the passage forming member 23 and blows gas at different flow rates through the vent holes 23b of the passage forming member 23 to the molding material Mm in the material feed passage 22. As shown in Fig. 10(b) or (c), the blower 30 changes the flow rate of the gas sent to the molding material Mm in the material feed passage 22 over time, thereby allowing the gas to be blown to the molding material Mm with varying strength. When sending gas from the blower 30 to the molding material Mm, a period of zero flow rate and a period of high flow rate may be repeated periodically as shown in Fig. 10(b), or a period of low flow rate and a period of high flow rate may be repeated periodically as shown in Fig. 10(c). Although the blower 30 can be provided separately as a retention prevention mechanism, the heater 24, which is the above-mentioned hot air heating type heater, can be used as the blower 30 and the heater 24 can also be used as a retention prevention mechanism. When the heater 24 is used both as a preheating mechanism and a retention prevention mechanism, the gas from the blower 30 corresponds to the heated gas from the heater 24.

[0059] 5 to 10, the above-mentioned retention prevention mechanisms may be adopted alone or in combination in the preheating device 21. In other words, the preheating device 21 may include one or more of the retention prevention mechanisms shown in FIGS.

[0060] Although not shown, the preheating device 21 is preferably provided with a retention detection mechanism that detects retention of the molding material Mm in the material feed passage 22. The retention detection mechanism may be, for example, a sensor that detects retention by temperature, an image captured by a camera, infrared rays, a laser, or the like.

[0061] Such a sensor of the retention detection mechanism is preferably provided at a portion on the leading end side of the material feed passage 22 in the material passing direction, that is, at a location near the material feed passage 22 before the supply container 26 for supplying the cylinder in the material passing direction. More specifically, as shown in Fig. 4, such a sensor 23d can be provided, for example, at a leading end side of the material feed passage 22 in the material passing direction, on the outer side of the passage width direction of the passage forming member 23, at intervals from each other in the lateral direction of the passage forming member 23. This makes it possible to find a location where retention of the molding material Mm occurs in the lateral direction of the passage forming member 23 at an early stage.

[0062] If the sensor 23d of the retention detection mechanism is a temperature sensor, it is preferable to arrange the temperature sensor so that it can measure the temperature of the molding material Mm located at the tip end portion in the material passing direction of the material feed passage 22. The temperature of the molding material Mm referred to here may be the temperature of the molding material Mm itself, the temperature of the passage forming member 23, or the temperature in the space within the ventilation hole 23b of the passage forming member 23. In the case of a contact type temperature sensor, to measure the temperature of the molding material Mm itself or the temperature of the passage forming member 23, for example, the temperature sensor is passed through the ventilation hole 23b of the passage forming member 23 and arranged so that its tip is in contact with the molding material Mm, or so that the tip of the temperature sensor is in contact with the passage forming member 23.

[0063] The aforementioned retention prevention mechanism can be operated continuously at all times while the injection molding machine is operating, or can be operated intermittently at specific times, such as when the retention detection mechanism detects retention of molding material Mm in the material feed passage 22.

[0064] 11 shows a preheating device 121 of another embodiment. This preheating device 121 has a supply container 127 for supplying passages and a supply container 126 for supplying cylinders, which are substantially similar to those of the previously described preheating device 21, but differs from the previously described preheating device 21 mainly in that a plurality of material feed passages 122 are provided in a housing 125 between them. By providing a plurality of material feed passages 122 in this way, the area per material feed passage 122 can be reduced, and the preheating device 121 can be made compact.

[0065] More specifically, the preheating device 121 has three material feed passages 122 arranged in parallel to each other, three pairs of passage forming members 123 dividing each of the material feed passages 122, and a heater 124 for heating the molding material Mm in the material feed passages 122 from the outside in the passage width direction separated by the material feed passages 122 and the passage forming members 123, in order to feed the molding material Mm from a supply container 127 for supplying a passage to a supply container 126 for supplying a cylinder. Three openings 126c corresponding to the number of the material feed passages 122 are provided at the end of the truncated cone portion 126a of the supply container 126.

[0066] As in the illustrated embodiment, it is preferable to provide heaters 124 on both sides of each material feed passage 122 in the passage width direction from the viewpoint of realizing rapid and uniform preheating of the molding material Mm. This preheating device 121 is also configured such that at least one of a pair of passage forming members 123 forming each material feed passage 122 is movable, so that the passage width of each material feed passage 122 can be adjusted. Although not illustrated, it is also possible to provide two or four or more material feed passages.

[0067] Fig. 12 shows a preheating device 221 of still another embodiment. The preheating device 221 of Fig. 12 is provided with a pair of belt conveyors 223a including a plurality of rollers 223b including a drive roller and a driven roller, and a path forming member 223 which is an endless circular belt wound around the rollers 223b. A material feed path 222 through which the molding material Mm passes is defined between the belt conveyors 223a.

[0068] Each of the pair of belt conveyors 223a rotates and drives the path forming member 223 as a belt by the driving roller of the roller 223b, whereby the molding material Mm is sandwiched between the pair of belt conveyors 223a and conveyed through the material feed path 222 therebetween. The molding material Mm that has passed through the material feed path 222 is introduced into a supply container 226 for cylinder supply such as a hopper. This supply container 226 has a truncated cone-shaped portion 226a and a cylindrical portion 226b similar to the supply container 26 of the preheating device 21 described above, and further has a cylindrical opening 226c at the upper end of the truncated cone-shaped portion 226a for receiving the molding material Mm from the belt conveyor 223a. In this example, the molding material Mm is fed horizontally through the material feed passage 222 and then charged into the supply container 226. However, the pair of belt conveyors 223a may be arranged at an incline or perpendicular to the horizontal direction, so that the material passes through the material feed passage 222 in a direction at an incline or perpendicular to the horizontal direction.

[0069] The heater 224 is disposed outside the belt conveyor 223a in the passage width direction. When the heater 224 is the hot air heater described above, each belt as the passage forming member 223 can be made of, for example, the mesh member described above so that a heated gas can pass through. This allows the heated gas to be sent to the molding material Mm passing through the material feed passage 222, and the molding material Mm can be effectively heated.

[0070] In addition, in order to adjust the passage width of the material feed passage 222, which is the distance between the pair of belt conveyors 223a, the preheating device 221 is configured to be able to move at least one of the pair of belt conveyors 223a together with the passage forming member 223 included therein, as shown by the white arrow in Figure 12.

[0071] (Control of pre-heating device) The above-described preheating devices 21, 121, and 221 can be controlled, for example, as described below. Note that, here, as an example, the control of the preheating device 21 out of the preheating devices 21, 121, and 221 will be described.

[0072] As described above, when the preheating device 21 is in use, the temperature of the molding material Mm at the tip end of the material feed passage 22 in the material passing direction is constantly monitored by the sensor 23d, or the like, provided as a retention detection mechanism or the like at the tip end of the material feed passage 22 in the material passing direction. Information on the temperature of the molding material Mm measured in this way is transmitted to, for example, the control unit of the injection molding machine.

[0073] 13(a), the molding material Mm is heated by the heating gas Gh or the like, and the temperature increases as it advances in the material passing direction through the material feed passage 22. At this time, the heating temperature of the heater 24 and other conditions may be set so that the temperature of the molding material Mm is less than a predetermined allowable upper limit value Tu that is lower than the melting point Tm of the molding material Mm. The allowable upper limit value Tu may be set to a temperature, for example, about 10° C. lower than the melting point Tm.

[0074] Here, if the operation of the injection molding machine stops for some reason, or if the sensor 23d serving as a retention detection mechanism detects retention of the molding material Mm in the material feed passage 22 regardless of whether the retention prevention mechanism is operating or not, the temperature of the molding material Mm may rise in the material feed passage 22 as shown in Fig. 13(b). If the temperature of the molding material Mm approaches the melting point Tm or exceeds the melting point Tm, there is a concern that the molding materials Mm may melt and fuse together or the molding material Mm may melt and fuse to the passage forming member 23, preventing the molding material Mm from passing through the material feed passage 22.

[0075] To prevent this, when the operation of the injection molding machine stops or when the retention of the molding material Mm in the material feed passage 22 is detected (for example, when retention of the molding material Mm is detected while the retention prevention mechanism is continuously operating, or when retention of the molding material Mm is detected in the material feed passage 22 while the retention prevention mechanism is not operating, and the retention is not eliminated even when the retention prevention mechanism is operated in response to that, and the retention is still detected), an operation stop signal or retention detection signal is sent to the control unit. In response to this, the control unit sends a heating stop signal to the preheating device 21 to stop heating the molding material Mm by the heater 24, and the preheating device 21 stops heating the molding material Mm by the heater 24. That is, the preheating device 21 stops heating the molding material Mm by the heater 24 based on information on the stop of the operation of the injection molding machine and / or information on the retention of the molding material Mm in the material feed passage 22.

[0076] The operation of the injection molding machine may be stopped, for example, when production is completed, when an abnormality is detected, when an emergency stop button is pressed, etc. Such stops can be detected by various sensors, etc.

[0077] Even when heating of the molding material Mm by the heater 24 is stopped, residual heat may cause the temperature of the molding material Mm to rise in the material feed passage 22. Therefore, when the temperature of the molding material Mm measured by the temperature sensor meets a predetermined standard after heating by the heater 24 is stopped, the molding material Mm in the material feed passage 22 is cooled, for example, by a cooling gas Gc, as shown in Fig. 13(c).

[0078] The above-mentioned predetermined standard for starting cooling of the molding material Mm can be a standard determined by comparing the actual measured value of the temperature of the molding material Mm with the allowable upper limit Tu. Specifically, the cooling of the molding material Mm can be started when the actual measured value of the temperature of the molding material Mm reaches the allowable upper limit Tu. Alternatively, the above-mentioned predetermined standard can be determined by estimating the amount of temperature rise that the molding material Mm may rise to in the future from the difference between the temperature of the molding material Mm and the ambient temperature of the preheating device 21, and comparing the estimated amount of temperature rise with the allowable upper limit Tu. Alternatively, the above-mentioned predetermined standard can be determined by comparing the estimated value of the temperature of the molding material Mm with the allowable upper limit Tu. In other words, the preheating device 21 cools the molding material Mm in the material feed passage 22 based on information about the temperature of the molding material Mm.

[0079] The cooling of the molding material Mm can be achieved by configuring the heater 24 as a hot air heating type heater or the blower section 30 to be capable of blowing room temperature gas such as cold air or cooling gas Gc. In addition, a cooling section for cooling the molding material Mm in the material feed passage 22 may be provided in the pre-heating device 21, separate from the heater 24 and the blower section 30. This effectively prevents the material feed passage 22 from being blocked by the melting of the molding material Mm.

[0080] An example of the above-mentioned control is shown in FIG. 14. In FIG. 14, first, the molding material Mm is passed through the preheating device 21 and then supplied into the cylinder 11 to form a molded product. If the operation of the injection molding machine stops during this time, the heater 24 is stopped. Even if the operation of the injection molding machine is not stopped, for example, if the molding material Mm is stuck in the material feed passage 22 while the retention prevention mechanism is continuously operating, the heater 24 is stopped. Note that if the operation of the injection molding machine is not stopped and the retention of the molding material Mm occurs in the material feed passage 22 while the retention prevention mechanism is stopped, the retention prevention mechanism is first operated, and if the retention is not resolved, the heater 24 is stopped. If the operation of the injection molding machine is not stopped and the retention of the molding material Mm does not occur, molding is continued. Note that the order of checking whether the operation of the injection molding machine has stopped and checking whether the retention of the molding material Mm has occurred may be reversed, or only one of them may be checked.

[0081] Next, after stopping the heater 24, it is confirmed whether or not the temperature of the molding material Mm is equal to or higher than the allowable upper limit. If the temperature of the molding material Mm is equal to or higher than the allowable upper limit, the molding material Mm is cooled, and it is confirmed again whether or not the temperature of the molding material Mm is equal to or higher than the allowable upper limit. When the temperature of the molding material Mm is below the allowable upper limit, it is determined whether or not molding should be resumed. When it is determined that molding may be resumed, molding is resumed.

[0082] (injection device) An injection device 1 to which the above-mentioned preheating device 21 and the like can be applied mainly comprises, as illustrated in FIG. 1, the preheating device 21, a cylinder 11 for melting the molding material supplied from the preheating device 21 therein, a screw 12 for plasticizing the molding material by being rotated inside the cylinder 11, a metering motor 31 arranged on the rear side in the direction of the rotation axis of the screw 12 (the right side in FIG. 1), and an injection motor 41 arranged further rearward of the metering motor 31.

[0083] A heater 13 is arranged around the cylinder 11 to heat the molding material plasticized by the screw 12 inside the cylinder 11. The cylinder 11 has a tip portion 14 with smaller inner and outer diameters at the tip side in the rotation axis direction (left side in FIG. 1), and heaters 13 are also arranged around the tip portion 14. In addition, a through-hole-shaped supply port 11a is provided at the rear end side in the rotation axis direction of the cylinder 11, and the above-mentioned preheating device 21 is attached thereto.

[0084] The metering motor 31 and the injection motor 41 are fixed to the rear surfaces of the rear ends in the rotation axis direction of two motor support plates 32, 42, which are arranged at a distance from each other in an upright position on the slide base 101. The screw 12 is driven to rotate by the metering motor 31, and driven to move forward and backward by the injection motor 41. The two motor support plates 32, 42 are connected to each other by rods 51, 52 at multiple points on the upper and lower sides separated by the metering motor 31.

[0085] The metering motor 31 mainly includes a rotor 33, a stator 34 arranged around the rotor 33, and a stator frame 35 that surrounds the rotor 33 and the stator 34 and has the stator 34 provided on its inner surface. The rotor 33 of the metering motor 31 is supported by bearings 33a inside the stator frame 35 at each end in the direction of its rotation axis. The rotor 33 is splined around a metering spline shaft 36, and the metering spline shaft 36 is connected to a screw mounting portion 37 to which the screw 12 is attached. At the rear end in the direction of the rotation axis of the outer circumferential surface of the metering spline shaft 36, one or more keys 36a corresponding to the key grooves provided on the inner circumferential surface of the rotor 33 are formed. This allows a rotational driving force to be transmitted from the metering motor 31 to the screw 12, thereby rotating the screw 12.

[0086] The injection motor 41 mainly includes a rotor 43, a stator 44 arranged around the rotor 43, and a stator frame 45 that is provided around the rotor 43 and the stator 44 and has the stator 44 on its inner surface. The rotor 43 is supported by bearings 43a inside the stator frame 45 at each end in the direction of its rotation axis. In the injection motor 41, the rotor 43 is connected to a drive shaft. More specifically, the drive shaft includes an injection spline shaft 46 splined at a groove 43b provided on the inner periphery of the cylindrical rotor 43, a threaded shaft 48 connected to the injection spline shaft 46, and a rotating shaft 50 rotatably attached to the inside of the metering spline shaft 36 via a bearing 49. A threaded nut 47 that screws onto the threaded shaft 48 is attached to the motor support plate 42 via a pressure detector 38, which will be described later. With this structure, the rotational driving force of the injection motor 41 is converted into a linear driving force in the direction of the rotation axis of the screw 12 and transmitted to the screw 12 .

[0087] A pressure detector 38 is disposed between the stator frame 45 of the injection motor 41 and the motor support plate 42. The pressure detector 38 is attached to the motor support plate 42 and the screw nut 47, and detects the load acting on the pressure detector 38 in the transmission path of the driving force from the injection motor 41 to the screw 12. A cylindrical portion 39 is provided between the pressure detector 38 and the stator frame 45. Further, an encoder 45a that is connected to the rotor 43 by a shaft portion 45b and detects the rotation of the rotor 43 is provided on the rear end surface of the stator frame 45 of the injection motor 41, which is located on the opposite side to the drive shaft in the rotation axis direction.

[0088] To give an example of a molding process using an injection molding machine equipped with such an injection unit 1, a mold clamping process is performed in which a mold unit (not shown) is closed to clamp the mold, with a predetermined amount of molding material already measured and placed inside the cylinder 11 in the latter half of the previous molding process. Next, a filling process is performed in which the molding material is injected into the mold unit by advancing the screw 12 to fill the cavity in the mold unit with the molding material, and a pressure holding process is performed in which the molding material inside the tip 14 of the cylinder 11 is maintained at a predetermined pressure by further advancing the screw 12.

[0089] Then, a cooling process is performed in which the molding material filled in the mold device is cooled and hardened to obtain a molded product. At this time, a measuring process is performed in which the molding material separately supplied from the preheating device 21 into the cylinder 11 is melted while being sent toward the tip 14 of the cylinder 11 by the rotation of the screw 12 under heating by the heater 13, and a predetermined amount of the molding material is placed at the tip 14.

[0090] In this embodiment, the molding material supplied into the cylinder 11 has already been heated to an appropriate temperature by the preheating device 21. Therefore, even if the screw 12 is rotated at high speed and the molding material is sent to the tip 14 of the cylinder 11 in a short time, the molding material can be sufficiently plasticized. This shortens the time required for metering, and makes it possible to shorten the molding cycle.

[0091] After that, the mold assembly is opened to bring it into an open state, and an ejection step is performed in which the molded product is ejected from the mold assembly by an ejector device or the like.

[0092] [Second Invention] In this embodiment, the preheating device 81 is for preheating the molding material, and by being provided in the injection device 1 as illustrated in FIG. 15, the preheated molding material can be supplied to the injection device 1. The injection device 1 illustrated in FIG. 15 is an injection molding machine, and is disposed, for example, on a slide base 101 of a moving device that moves the injection device 1 forward and backward, and injects the molding material into a mold device. The injection device 1 can be provided with the preheating device 81 and a cylinder 11 to which the molding material preheated by the preheating device is supplied and melts the molding material inside. The illustrated injection device 1 further includes a screw 12 that is rotated and driven inside the cylinder 11 to plasticize the molding material, a heater 13 that is provided around the cylinder 11 to heat the molding material inside the cylinder 11, and the detailed structure of the injection device 1 will be described later.

[0093] (Preheating device) The preheating device 81 is attached to the rear end of the cylinder 11 on the opposite side to the tip end 14 that injects the molding material, in the direction of the rotation axis of the screw 12 of the injection device 1 (left and right direction in Fig. 15). More specifically, the preheating device 81 is connected to a through-hole-like supply port 11a provided on a part of the circumference of the rear end of the cylinder 11, as shown in Fig. 16, and supplies molding material Mm, such as resin pellets having substantially spherical or cylindrical shapes or other shapes, to the supply port 11a.

[0094] In this embodiment, the preheating device 81 has a material feed passage 82 through which the molding material Mm passes. The material feed passage 82 is defined by the inner circumferential surface of a tubular body 83 such as a pipe made of metal (in other words, the material feed passage 82 is formed inside the tubular body 83). The material feed passage 82 has a junction 82a where the molding material Mm and the heating medium Gh join together, and an in-line mixing section 82b that mixes the molding material Mm and the heating medium Gh that have joined at the junction 82a and heats the molding material Mm with the heating medium Gh. Therefore, as shown in Figure 16, the molding material Mm is supplied to the supply port 11a of the cylinder 11 through the material feed passage 82 from upstream (left side of Figure 16) to downstream (right side of Figure 16) in the material passing direction, and along the way passes through a junction section 82a where it merges with the heating medium Gh, and then a mixing section 82b where the molding material Mm and the heating medium Gh are mixed.

[0095] In the preheating device 81 having such a configuration, the molding material Mm to be supplied inside the cylinder 11 can be preheated before being supplied. As a result, the preheated molding material Mm is supplied into the cylinder 11 through the supply port 11a, and then sufficiently melted inside the cylinder 11 within a short period of time, and then injected from the tip of the cylinder 11, thereby realizing a shortened molding cycle.

[0096] Here, in the illustrated example, the material feed passage 82 has a first portion 821 extending vertically (up and down in the drawing) from upstream to downstream in the material passing direction, a second portion 822 extending horizontally (left and right in the drawing) following the vertical lower end (downstream side in the material passing direction) of the first portion 821, and a third portion 823 extending vertically following the downstream side in the material passing direction of the second portion 822. At the vertical upper end of the first portion 821, the molding material Mm is supplied into the material feed passage 82, and the second portion 822 has a junction portion 82a and a mixing portion 82b, and the third portion 823 is connected at its vertical lower end to a supply container 26 described later. The size of the material feed passage 82 can be arbitrarily determined depending on the amount of molding material Mm to be conveyed, the heating temperature, etc. Also, the shape of the material feed passage 82 is not limited to that shown in Fig. 16, and can be any shape. Furthermore, a heat insulating material can be provided around the tubular body 83 that forms the material feed passage 82.

[0097] The junction 82a in the material feed passage 82 is a section where the heating medium Gh heated by the heater 84 is sent from the heater 84 through the heat medium feed passage 84a and joins with the molding material Mm being transported from upstream to downstream in the material passing direction. The heating medium Gh may be a heating gas, specifically, a gas such as air or an inert gas that has been heated, or superheated steam. However, the heating medium Gh is not particularly limited as long as it can merge with the molding material Mm at the merging portion 82a and flow downstream in the material passing direction. The heating medium Gh is heated by a heater 84 of the preheating device 81, and the heater 84 may be, for example, a hot air heater. The hot air heater may be, for example, a heater that heats compressed air sent from a compressor with a sheath heater or the like to obtain hot air. The temperature of the hot air can be adjusted by changing the output of the sheath heater. The heating medium Gh is sent to the merging portion 82a through a heat medium sending passage 84a of the preheating device 81, and the heat medium sending passage 84a between the heater 84 and the merging portion 82a may be partitioned by, for example, a pipe 84b made of metal and surrounded by a heat insulating material.

[0098] The heating medium Gh is generated by the heater 84 and then sent to the junction 82a of the material sending passage 82 via the heating medium sending passage 84a in FIG. As described above, at the confluence 82a, the heat transfer medium feed passage 84a branches off from the material feed passage 82, but between the confluence 82a and the heat transfer medium feed passage 84a, a passage prevention section such as a mesh can be provided to prevent the molding material Mm from being fed to the heat transfer medium feed passage 84a.

[0099] The mixing section 82b is a section where the molding material Mm and the heating medium Gh that have joined at the joining section 82a are mixed in-line and the molding material Mm is heated by the heating medium Gh. By providing the joining section 82a, the molding material Mm and the heating medium Gh join at the joining section 82a and are sent in the material passing direction together with the heating medium Gh, so that the molding material Mm and the heating medium Gh come into contact with each other, and the molding material Mm can be partially heated. However, the molding material Mm is not heated sufficiently uniformly and efficiently in a short time by only contacting with the heating medium Gh. Therefore, by providing the mixing section 82b in the material feed passage 82, the flow of the molding material Mm and the heating medium Gh can be homogenized, and the molding material Mm can be heated uniformly. In addition, by effectively mixing, the molding material Mm is sufficiently heated from the entire surface, enabling high-speed heating.

[0100] 16, a static mixer that is an in-line mixer without a drive unit is used as the mixer 82b. The static mixer in the illustrated example specifically includes a plurality of spirally twisted plates 82c provided in the material feed passage 82. By including such spiral plates 82c, the flow of the molding material Mm and the heating medium Gh passes through the mixer 82b while being divided, diverted, and reversed, and the molding material Mm can be efficiently and uniformly heated in a short time.

[0101] As shown in FIG. 17 (two plates are shown in FIG. 17), the spiral plate 82c has a spiral shape formed by twisting a flat plate about 180° around an axis, and the spiral plate 82c is arranged so that the axis is along the material passing direction in the material feed passage 82. Adjacent spiral plates 82c have opposite twist directions around the axis, and the ends of the plates 82c are joined in a direction that is approximately perpendicular to each other. A static mixer including such a spiral plate 82c preferably includes a plurality of the spiral plates 82c, which allows the molding material Mm and the heating medium Gh to be effectively mixed. The spiral plate 82c can be made of metal. However, the static mixer is not limited to the spirally twisted plate 82c as described above, and may be any mixer that can increase the contact efficiency between the molding material Mm and the heating medium, for example, by changing the flow direction of the heating medium and / or partially narrowing the material feed passage 82. In this embodiment, the mixer 82b is not limited to the above mixer, and any mixer can be used as long as it can mix the molding material Mm and the heating medium Gh in-line, and may or may not have a drive unit. Also, a mixer capable of in-line mixing without a drive unit is preferable. By using such a mixer, for example, the mixer can be installed in an existing conveying path for the molding material Mm as the material feed passage 82, and the equipment introduction cost can be reduced.

[0102] In addition, the preheating device 81 of this embodiment is equipped with a conveyor 85 that conveys the molding material Mm from the upstream to the downstream of the material feed passage 82, and in the example of Fig. 16, the conveyor 85 is a gas pressure feeder that pressure-feeds the molding material Mm. More specifically, the gas pressure feeder 85 introduces compressed gas Gp produced by a compressor (not shown) or the like into the gas pressure feeder 85 as shown in Fig. 18, and generates a discharge-side gas flow Gb from the compressed gas Gp toward the downstream side of the material passing direction of the material feed passage 82 (the right side in Fig. 18) (in other words, the discharge port for generating the discharge-side gas flow Gb faces the downstream side of the material passing direction), so that the upstream side (the left side in Fig. 18) of the discharge part that discharges the compressed gas Gp into the discharge-side gas flow Gb becomes negative pressure. This generates a suction-side gas flow Gf that is sucked downstream upstream of the gas pump 85 in the material passing direction, and transports the molding material Mm present on the upstream side of the material feed passage 82 in the material passing direction downstream. 16, in this embodiment, the gas pump 85 is provided upstream of the junction 82a in the material feed passage 82, so that the gas pump 85 sucks and transports the molding material Mm present upstream in the material feed passage 82 in the material passing direction to the junction 82a, and then passes the molding material Mm together with the heating medium Gh through the mixing section 82b, and pumps and transports the molding material Mm to the downstream side of the material feed passage 82. In addition, the gas pump 85 is provided upstream of the junction 82a in the material feed passage 82, so that the heating medium Gh can be prevented from flowing back upstream in the material passing direction. By using a gas pressure feeder for pressure-feeding the molding material Mm as the conveyor 85 in this manner, for example, an existing conveying path for the molding material Mm can be used, and the equipment introduction cost can be reduced. When a gas pressure feeder is used as the conveyor 85, the compressed gas Gp is ​​not particularly limited and air can be used. In addition, the material feed passage 82 can be provided with an outlet (not shown) for discharging the heating medium Gh, downstream in the material passing direction and before the supply port 11a of the cylinder 11, for example, in the supply container 26 in the example shown in Fig. 16, and the outlet can also be used to exhaust the gas from the gas pressure feeder 85 introduced for conveyance.

[0103] In another embodiment, in the preheating device 181, a gas compressor as a conveying device 185 is provided downstream of the mixing section 182b in the material feed passage 182 in the material passing direction as shown in FIG. 19, and the molding material Mm can be conveyed via the confluence section 182a and the mixing section 182b in the material feed passage 182 by the downstream suction force generated upstream of the gas compressor 185 in the material passing direction. In yet another embodiment, instead of the above-mentioned gas pressure feeder, a feed screw 285 is used as the conveyor 285 in the preheating device 281 as shown in FIG. 20. By providing the feed screw 285 upstream of the material passing direction of the material feed passage 282, the molding material Mm can be conveyed through the junction 282a and the mixing section 282b so as to be pushed out of the material feed passage 282. The feed screw 285 shown in FIG. 20 includes a screw 285a that rotates the molding material Mm to move it, a cylindrical cylinder 285b that contains the screw 285a, and a drive unit 285c that rotates the screw 285a. In addition, a supply container 227 (hopper) is connected to an opening 285d on the drive unit 285c side of the cylinder 285b of the feed screw 285, and the molding material Mm is supplied from the supply container 227. Furthermore, in the feed screw 285, the material feed passage 282 is connected to an opening 285e on the tip side of the cylinder 285b, and the molding material Mm is fed into the material feed passage 282 from the opening 285e.

[0104] In this embodiment, a supply container 26 for supplying a cylinder such as a hopper is provided on the downstream side (lower end side in FIG. 16) of the material passing direction of the material feed passage 82. In the illustrated example, the supply container 26 has, for example, a truncated cone-shaped portion 26a whose inner and outer shapes are both truncated cones, and a cylindrical portion 26b formed at the end of the small diameter side of the truncated cone-shaped portion 26a. The supply container 26 receives the molding material Mm that has passed through the material feed passage 82 in the truncated cone-shaped portion 26a, and then supplies the molding material Mm through the cylindrical portion 26b at the end of the truncated cone-shaped portion 26a to the inside of the cylinder 11. An opening 26c having a width approximately the same as that of the material feed passage 82 is formed at the end of the truncated cone-shaped portion 26a, and the molding material Mm that has passed through the material feed passage 82 enters the supply container 26 from the opening 26c.

[0105] In addition, upstream of the material passing direction of the material feed passage 82, a supply container 27 for supplying the passage, such as a hopper, which stores multiple molding materials Mm and supplies the molding materials Mm in an appropriate amount to the material feed passage 82, is placed in front of the conveyor 85.

[0106] In the illustrated example, the molding material Mm is supplied from the supply container 27 for supplying the passage to the preheating device 81. The molding material Mm supplied to the preheating device 81 passes through the material feed passage 82 while being preheated, and is supplied to the inside of the cylinder 11 after passing through the supply container 26 for supplying the cylinder. That is, here, the molding material Mm preheated by the preheating device 81 is supplied to the inside of the cylinder 11. However, the shape of the supply container 26 and / or the supply container 27 is not limited to this, and can be appropriately changed, and the supply container 26 and / or the supply container 27 may be omitted. If the supply container 26 for the cylinder is omitted, the preheating device is disposed on the cylinder, and the tip side of the material feed passage in the material passing direction is directly connected to the supply port of the cylinder. In this case, the molding material preheated by the preheating device is supplied to the inside of the cylinder immediately after the preheating.

[0107] In the embodiment shown in FIG. 16, as the plasticization by the screw 12 or the like inside the cylinder 11 progresses, the molding material Mm is supplied from the supply container 26 for supplying the cylinder to the inside of the cylinder 11. Accordingly, the molding material Mm in the supply container 27 for supplying the passage passes through the material feed passage 82, is heated by the heater 84, and then is fed into the supply container 26 for supplying the cylinder. In this case, the speed of the molding material Mm passing through the material feed passage 82 may depend on the speed of plasticization of the molding material Mm inside the cylinder 11, but the passing speed of the molding material Mm can also be adjusted by the conveyor 85 as described above. In addition, in order to adjust the speed at which the molding material Mm passes through the material feed passage 82 and the degree of heating of the molding material Mm influenced by it, a screw-shaped feeder or other supply adjuster for adjusting the supply of the molding material Mm from the material feed passage 82 to the supply container 26 may be provided between the material feed passage 82 and the supply container 26, although not shown in the figure.

[0108] In this embodiment, the preheating device 81 is preferably provided with a retention detection mechanism (not shown) that detects retention of the molding material Mm in the material feed passage 82. The retention detection mechanism may be, for example, a sensor that detects retention based on temperature or the like. By providing the retention detection mechanism, it is possible to detect an excessive rise in temperature of the molding material Mm at an early stage, for example, when the molding material Mm is retained due to a stop of the injection device. The temperature of the molding material Mm referred to here may be the temperature of the molding material Mm itself, the temperature in the space in the material feed passage, or the temperature of the tubular body that forms the material feed passage. Such a sensor of the retention detection mechanism is preferably provided at the confluence portion 82a or the mixing portion 82b of the material feed passage 82, or at a location near the downstream side thereof.

[0109] (Control of pre-heating device) The above-described preheating devices can be controlled, for example, as follows. Note that, here, as an example, the control of the preheating device 81 out of the preheating devices 81, 181, and 281 will be described.

[0110] As described above, when the preheating device 81 is in use, the temperature of the molding material Mm in the material feed passage 82 is constantly monitored by a temperature sensor or the like provided in the material feed passage 82 as a retention detection mechanism or the like. Information on the temperature of the molding material Mm measured in this way is transmitted to, for example, the control unit of the injection molding machine.

[0111] During normal operation, the heating temperature of the heater 84 and other conditions may be set so that the temperature of the molding material Mm is less than a predetermined allowable upper limit Tu that is lower than the melting point Tm of the molding material Mm. The allowable upper limit Tu may be set to a temperature that is, for example, about 10° C. lower than the melting point Tm.

[0112] Here, if the operation of the injection molding machine stops for some reason, the temperature of the molding material Mm may rise in the material feed passage 82. If the temperature of the molding material Mm approaches the melting point Tm or exceeds the melting point Tm, there is a concern that the molding materials Mm may melt and fuse to each other or to the tubular body 83, making it impossible for the molding material Mm to pass through the material feed passage 82.

[0113] To prevent this, when the operation of the injection molding machine stops or when the accumulation of molding material Mm in the material feed passage 82 is detected, an operation stop signal or accumulation detection signal is sent to the control unit. In response to this, the control unit sends a heating stop signal to the preheating device 81 to stop heating the molding material Mm by the heater 84, and the preheating device 81 stops heating the molding material Mm by the heater 84. In other words, the preheating device 81 stops heating the molding material Mm by the heater 84 based on information about the stop of operation of the injection molding machine and / or information about the accumulation of molding material Mm in the material feed passage 82.

[0114] Even when heating of the molding material Mm by the heater 84 is stopped, residual heat may cause the temperature of the molding material Mm to rise in the material feed passage 82. Therefore, after heating by the heater 84 is stopped, when the temperature of the molding material Mm measured by the temperature sensor meets a predetermined standard, the molding material Mm in the material feed passage 82 is cooled, for example, by cooling gas Gc or the like.

[0115] The above-mentioned predetermined standard for starting cooling of the molding material Mm can be a standard determined by comparing the actual measured value of the temperature of the molding material Mm with the allowable upper limit Tu, and specifically, cooling of the molding material Mm can be started when the actual measured value of the temperature of the molding material Mm reaches the allowable upper limit Tu. Alternatively, the above-mentioned predetermined standard can be determined by estimating the amount of temperature rise that the molding material Mm may rise to in the future from the difference between the temperature of the molding material Mm and the ambient temperature of the preheating device 81, and comparing the estimated amount of temperature rise with the allowable upper limit Tu. In other words, the preheating device 81 cools the molding material Mm in the material feed passage 82 based on information about the temperature of the molding material Mm.

[0116] The cooling of the molding material Mm can be realized by using a hot air heating type heater of the heater 84 or by configuring a blower (not shown) to blow room temperature gas such as cold air or a cooling gas Gc. This effectively prevents the material feed passage 82 from being blocked by the melting of the molding material Mm.

[0117] An example of the above-mentioned control is shown in FIG. 21. In FIG. 21, first, the molding material Mm is passed through a preheating device 81 and then supplied into the cylinder 11 to form a molded product. If the operation of the injection molding machine stops during this time, the heater 84 is stopped. Even if the operation of the injection molding machine is not stopped, if the molding material Mm is stagnating in the material feed passage 82, the heater 84 is stopped. If the operation of the injection molding machine is not stopped and no stagnating of the molding material Mm is occurring, molding is continued. Note that the order of checking whether the operation of the injection molding machine has stopped and checking whether the molding material Mm is stagnating may be reversed, or only one of the checks may be performed.

[0118] Next, after stopping the heater 84, it is confirmed whether or not the temperature of the molding material Mm is equal to or higher than the allowable upper limit. If the temperature of the molding material Mm is equal to or higher than the allowable upper limit, the molding material Mm is cooled, and it is confirmed again whether or not the temperature of the molding material Mm is equal to or higher than the allowable upper limit. When the temperature of the molding material Mm is below the allowable upper limit, it is determined whether or not molding should be resumed. When it is determined that molding may be resumed, molding is resumed.

[0119] (injection device) An injection device 1 to which the above-mentioned preheating device 81 and the like can be applied mainly comprises, as illustrated in FIG. 15, the preheating device 81, a cylinder 11 for melting the molding material supplied from the preheating device 81 therein, a screw 12 for plasticizing the molding material by being rotated inside the cylinder 11, a metering motor 31 arranged on the rear side in the direction of the rotation axis of the screw 12 (the right side in FIG. 15), and an injection motor 41 arranged further rearward of the metering motor 31.

[0120] A heater 13 is arranged around the cylinder 11 to heat the molding material plasticized by the screw 12 inside the cylinder 11. The cylinder 11 has a tip portion 14 with a smaller inner and outer diameter at the tip side in the rotation axis direction (left side in FIG. 15), and heaters 13 are also arranged around the tip portion 14. In addition, a through-hole-shaped supply port 11a is provided at the rear end side in the rotation axis direction of the cylinder 11, and the above-mentioned preheating device 81 is attached thereto.

[0121] The metering motor 31 and the injection motor 41 are fixed to the rear surfaces of the rear ends in the rotation axis direction of two motor support plates 32, 42, which are arranged at a distance from each other in an upright position on the slide base 101. The screw 12 is driven to rotate by the metering motor 31, and driven to move forward and backward by the injection motor 41. The two motor support plates 32, 42 are connected to each other by rods 51, 52 at multiple points (for example, four points) around the metering motor 31.

[0122] The metering motor 31 mainly includes a rotor 33, a stator 34 arranged around the rotor 33, and a stator frame 35 that surrounds the rotor 33 and the stator 34 and has the stator 34 provided on its inner surface. The rotor 33 of the metering motor 31 is supported by bearings 33a inside the stator frame 35 at each end in the direction of its rotation axis. The rotor 33 is splined around a metering spline shaft 36, and the metering spline shaft 36 is connected to a screw mounting portion 37 to which the screw 12 is attached. At the rear end in the direction of the rotation axis of the outer circumferential surface of the metering spline shaft 36, one or more keys 36a corresponding to the key grooves provided on the inner circumferential surface of the rotor 33 are formed. This allows a rotational driving force to be transmitted from the metering motor 31 to the screw 12, thereby rotating the screw 12.

[0123] The injection motor 41 mainly includes a rotor 43, a stator 44 arranged around the rotor 43, and a stator frame 45 that is provided around the rotor 43 and the stator 44 and has the stator 44 on its inner surface. The rotor 43 is supported by bearings 43a inside the stator frame 45 at each end in the direction of its rotation axis. In the injection motor 41, the rotor 43 is connected to a drive shaft. More specifically, the drive shaft includes an injection spline shaft 46 splined at a groove 43b provided on the inner periphery of the cylindrical rotor 43, a threaded shaft 48 connected to the injection spline shaft 46, and a rotating shaft 50 rotatably attached to the inside of the metering spline shaft 36 via a bearing 49. A threaded nut 47 that screws onto the threaded shaft 48 is attached to the motor support plate 42 via a pressure detector 38, which will be described later. With this structure, the rotational driving force of the injection motor 41 is converted into a linear driving force in the direction of the rotation axis of the screw 12 and transmitted to the screw 12 .

[0124] A pressure detector 38 is disposed between the stator frame 45 of the injection motor 41 and the motor support plate 42. The pressure detector 38 is attached to the motor support plate 42 and the screw nut 47, and detects the load acting on the pressure detector 38 in the transmission path of the driving force from the injection motor 41 to the screw 12. A cylindrical portion 39 is provided between the pressure detector 38 and the stator frame 45. Further, an encoder 45a that is connected to the rotor 43 by a shaft portion 45b and detects the rotation of the rotor 43 is provided on the rear end surface of the stator frame 45 of the injection motor 41, which is located on the opposite side to the drive shaft in the rotation axis direction.

[0125] To give an example of a molding process using an injection molding machine equipped with such an injection unit 1, a mold clamping process is performed in which a mold unit (not shown) is closed to clamp the mold, with a predetermined amount of molding material already measured and placed inside the cylinder 11 in the latter half of the previous molding process. Next, a filling process is performed in which the molding material is injected into the mold unit by advancing the screw 12 to fill the cavity in the mold unit with the molding material, and a pressure holding process is performed in which the molding material inside the tip 14 of the cylinder 11 is maintained at a predetermined pressure by further advancing the screw 12.

[0126] Then, a cooling process is performed in which the molding material filled in the mold device is cooled and hardened to obtain a molded product. At this time, a measuring process is performed in which the molding material separately supplied from the preheating device 81 into the cylinder 11 is melted while being sent toward the tip 14 of the cylinder 11 by the rotation of the screw 12 under heating by the heater 13, and a predetermined amount of the molding material is placed at the tip 14.

[0127] In this embodiment, the molding material supplied into the cylinder 11 has already been heated to an appropriate temperature by the preheating device 81. Therefore, even if the screw 12 is rotated at high speed and the molding material is sent to the tip 14 of the cylinder 11 in a short time, the molding material can be sufficiently plasticized. This shortens the time required for metering, and makes it possible to shorten the molding cycle.

[0128] After that, the mold assembly is opened to bring it into an open state, and an ejection step is performed in which the molded product is ejected from the mold assembly by an ejector device or the like.

[0129] [Third Invention] In this embodiment, the preheating device 60 is for preheating the molding material, and by being provided in the injection device 1 as illustrated in FIG. 22, the preheated molding material can be supplied to the injection device 1. The injection device 1 illustrated in FIG. 22 is an injection molding machine, and is disposed, for example, on a slide base 101 of a moving device that moves the injection device 1 forward and backward, and injects the molding material into a mold device. The injection device 1 can be provided with the preheating device 60 and a cylinder 11 to which the molding material preheated by the preheating device is supplied and melts the molding material inside. The illustrated injection device 1 further includes a screw 12 that is rotated and driven inside the cylinder 11 to plasticize the molding material, a heater 13 that is provided around the cylinder 11 to heat the molding material inside the cylinder 11, and the detailed structure of the injection device 1 will be described later.

[0130] (Preheating device) The preheating device 60 is attached to the rear end of the cylinder 11 on the opposite side to the tip end 14 that injects the molding material, in the direction of the rotation axis of the screw 12 of the injection device 1 (left and right direction in FIG. 22). More specifically, the preheating device 60 is connected to a through-hole-like supply port 11a provided on a part of the circumference of the rear end of the cylinder 11, as shown in FIG. 23, and supplies molding material Mm, such as resin pellets having substantially spherical or cylindrical shapes or other shapes, to the supply port 11a.

[0131] 22 to 24, the preheating device 60 has a material passage 61 through which the molding material Mm passes, and a superheated steam inlet 62 that introduces superheated steam Ss into the material passage 61 in order to heat the molding material Mm in the material passage 61. In the material passage 61, the molding material Mm is heated by the superheated steam Ss introduced from the superheated steam inlet 62. This allows the molding material Mm to be preheated before being supplied into the cylinder 11.

[0132] The superheated steam Ss introduced into the material passage 61 from the superheated steam inlet 62 can be generated by adding heat to the steam vaporized by boiling water in a superheated steam generator (not shown). Generally, heated air (hot air) heats the object to be heated by convection heat transfer, whereas superheated steam heats the object to be heated not only by convection heat transfer but also by radiation heat transfer and condensation heat transfer, and has a much larger thermal energy than heated air. Here, the molding material Mm is heated by the superheated steam Ss introduced from the superheated steam inlet 62, so that the temperature of the molding material Mm rises to a predetermined temperature in a short time. As a result, in this embodiment, the molding material Mm is preheated instantly, and the molding cycle by the injection molding machine can be shortened. This is particularly advantageous when applied to high cycle molding.

[0133] For example, the superheated steam generator may have a structure in which a heating device such as a sheath heater is provided in a thermally insulated housing. In this case, the superheated steam generator can generate superheated steam by heating saturated steam sent from a boiler or the like. The superheated steam inlet 62 can be supplied with superheated steam generated by a superheated steam generator that can be installed in an injection molding machine including an injection unit, or it can be supplied with superheated steam that is separately generated in a specified facility at the installation site, such as a factory, where the injection unit is installed.

[0134] As shown in the illustrated example, the preheating device 60 may further have a passage partition wall 63 of a cylinder or other tubular shape provided around the material passage 61. The material passage 61 is partitioned and provided inside the passage partition wall 63. In this particular example, the cylindrical passage partition wall 63 is arranged horizontally so that its central axis is, for example, substantially parallel to the horizontal rotation axis direction of the screw 12 (the left-right direction in Figs. 22-24). In the material passage 61 inside the passage partition wall 63, the molding material Mm moves in the rotation axis direction, so that the material passage direction, which is the direction in which the molding material Mm passes, becomes parallel to the rotation axis direction. However, the material passage 61 can be provided so that the material passage direction in the material passage 61 is a vertical direction perpendicular to the rotation axis direction of the screw 12 as in the embodiment described later, and the material passage 61 can also be provided obliquely so that the material passage is in a direction inclined with respect to the rotation axis direction of the screw 12 (not shown).

[0135] As shown in Fig. 24, a hole-shaped passage inlet 61a is provided at the rear end side (right side in Figs. 22 to 24) of the material passage 61 in the material passage direction by hollowing out a part in the circumferential direction of the passage partition wall 63. A substantially truncated cone-shaped hopper 61b can be attached to this passage inlet 61a. At the tip side of the material passage 61 in the material passage direction (left side in Figures 22 to 24), a passage outlet 61c is provided which protrudes toward the outer periphery of a part of the circumferential direction of the passage partition wall portion 63 and tapers toward the tip side, which is the lower side in the direction perpendicular to the material passage direction.

[0136] The preheating device 60 may further include a conveying mechanism that sends the molding material Mm in the material passage 61 in the material passage 61. In this embodiment, as an example of the conveying mechanism, a preheating screw 64 is provided in the material passage 61. In addition to the preheating screw 64, the conveying mechanism may be a belt conveyor or the like (not shown).

[0137] The illustrated preheating screw 64 includes a rotating shaft 65 that is driven to rotate about an axis along the material passage direction in the material passage 61, and a flight 66 that is provided upright on the outer circumferential surface of the rotating shaft 65 and extends in a predetermined shape such as a spiral around the axis, but the shape of the preheating screw 64 is not limited to this. When the preheating screw 64 is driven to rotate by a driving source 67 such as a motor, the molding material Mm is transported in the material passage 61 on the outer circumferential side of the rotating shaft 65 in the material passage direction by the flight 66 provided on the outer circumferential surface of the rotating shaft 65, as shown in FIG.

[0138] The preheating screw 64 in this embodiment is a hollow rotating shaft 65. Specifically, as can be seen from Fig. 24, the rotating shaft 65 has an internal space 68 therein, a cylindrical peripheral wall portion 69 that defines the internal space 68, and a plurality of communication holes 70 formed in the peripheral wall portion 69 by penetrating the peripheral wall portion 69. Here, the superheated steam inlet 62 is provided in the preheating screw 64, more specifically, in the tip surface in the rotational axis direction of the rotating shaft 65 of the preheating screw 64. For example, the tip portion in the rotational axis direction of the rotating shaft 65 of the preheating screw 64 can be positioned so as to be exposed to the outside of the passage partition wall portion 63 through an opening 63a provided in the end surface of the passage partition wall portion 63, and the superheated steam inlet 62 can be provided in the tip portion.

[0139] In the material passage 61 in which such a preheating screw 64 is disposed, the superheated steam Ss introduced into the material passage 61 from the superheated steam inlet 62 first flows into the internal space 68 of the rotating shaft 65 of the preheating screw 64 within the material passage 61. The superheated steam Ss that has flowed into the internal space 68 is then sent from the internal space 68 through a plurality of communication holes 70 provided in a peripheral wall portion 69 to the outer periphery of the rotating shaft 65. On the outer periphery of the rotating shaft 65, the molding material Mm being transported in the material passage direction by the flight 66 is heated by the superheated steam Ss that has passed through the communication holes 70.

[0140] In addition, the height of the outer periphery of the flight 66 from the outer periphery of the rotating shaft 65 (groove depth of the preheating screw 64) is preferably equal to or greater than the length of one piece of molding material Mm and less than the length of two pieces of molding material Mm. In this case, since the multiple molding materials Mm are prevented from overlapping in the radial direction of the preheating screw 64 on the outer periphery of the rotating shaft 65, each molding material Mm passing through the material passage 61 can be heated more effectively by, for example, superheated steam sent from the communication hole 70 of the rotating shaft 65 to the outer periphery. This effectively prevents unmelted material from being mixed with the molten molding material injected from the tip 14 of the cylinder 11, thereby preventing poor appearance and strength reduction of the molded product. In addition, it is preferable that the gap between the outer peripheral edge of the flight 66 and the inner peripheral surface of the passage partition wall 63 in the radial direction of the preheating screw 64 is narrower than the length of one piece of molding material Mm. This makes it possible to prevent the molding material Mm from climbing over the flight 66 in the rotation axis direction. A small gap is provided between the outer peripheral edge of the flight 66 and the inner peripheral surface of the passage partition wall 63 so that they do not come into contact with each other. Furthermore, it is preferable that the distance from the outer peripheral surface of the rotation shaft 65 of the preheating screw 64 to the inner peripheral surface of the passage partition wall 63 is equal to or greater than the length of one piece of molding material Mm and less than the length of two pieces of molding material Mm. The length of one piece of molding material Mm is preferably the shortest dimension of the molding material Mm. For example, if the molding material Mm is substantially spherical, the length is preferably the diameter of the molding material Mm, or if the molding material Mm is an irregular sphere having an ellipse or oval cross section, the length is preferably the diameter of the shortest short side of the molding material Mm. Alternatively, if the molding material Mm is cylindrical, prismatic, or other prismatic, the length of one piece of molding material Mm may be the shorter of the diameter or the width and height of the molding material Mm.

[0141] Instead of the above-mentioned superheated steam inlet 62, passage partition wall 63, and preheating screw 64, a superheated steam inlet 162, passage partition wall 163, and preheating screw 164 shown in FIG. 25 may be used. In FIG. 25, the passage partition wall 163 is provided with a plurality of superheated steam inlets 162 in the circumferential direction and the rotation axis direction, each of which is a through hole penetrating the passage partition wall 163. The preheating screw 164 may have a hollow or solid rotating shaft 165, but does not have the above-mentioned communication hole 70. In addition, no opening is provided on the end face of the passage partition wall 163, and the tip of the rotating shaft 165 in the rotation axis direction terminates inside the passage partition wall 163. In the embodiment shown in FIG. 25, superheated steam Ss is introduced into the material passage 61 from the superheated steam inlet 162 provided in the passage partition wall 163. This heats the molding material Mm being conveyed on the outer circumferential side of the rotating shaft 165. The embodiment shown in Fig. 25 has substantially the same configuration as those shown in Figs. 22 to 24, except for the structures of the superheated steam inlet 162, the passage partition wall portion 163, and the preheating screw 164.

[0142] Alternatively, as shown in Fig. 26, the configuration shown in Figs. 22 to 24 may be further provided with a plurality of through-hole-shaped superheated steam inlets 262 in a passage partition wall 263. In the embodiment shown in Fig. 26, the molding material Mm conveyed on the outer circumferential side of the rotation shaft 65 of the preheating screw 64 is heated by superheated steam sent from both the inner and outer sides in the radial direction (the vertical direction in Fig. 26) of the preheating screw 64 by the superheated steam inlet 262 in the passage partition wall 263 and the superheated steam inlet 62 in the preheating screw 64. The embodiment in Fig. 26 has substantially the same configuration as that shown in Figs. 22 to 24, except that the superheated steam inlet 262 is provided in the passage partition wall 263.

[0143] As described above, it is preferable that the communication holes 70 in the peripheral wall 69 of the preheating screw 64 and the superheated steam inlets 162, 262 in the passage partition walls 163, 263 are provided in large numbers and uniformly distributed in the circumferential direction and the rotation axis direction of the peripheral wall 69 or the passage partition walls 163, 263. In order to realize such a preheating screw 64 and the passage partition walls 163, 263, the peripheral wall 69 and / or the passage partition walls 163, 263 can be made of, for example, a cylindrical mesh member having a plurality of holes having a square or other polygonal shape when viewed from the front, or a cylindrical plate member such as a so-called punching metal in which a plurality of holes are formed by pressing a metal plate. If the mesh member is not strong enough, the peripheral wall 69 and / or the passage partition walls 163, 263 may be made of a mesh member superimposed on a reinforcing member having a honeycomb or lattice shape.

[0144] For example, when the plasticizing ability of the cylinder 11 of the injection device 1 is high and it is required to supply the molding material Mm to the cylinder 11 at a higher speed, the outer diameter of the preheating screw 64, 164 can be increased. Alternatively, as shown in a cross-sectional view of the material passage from above in FIG. 27, a material passage 361 for sending the molding material Mm to one passage outlet 361c is arranged around the passage outlet 361c at an angle of 90° with a passage partition wall 363 surrounding it and a preheating screw 364 inside it in the example shown in FIG. 27, but the number and arrangement of the material passages 361 can be changed as appropriate. When a plurality of material passages 361 are provided, a superheated steam inlet is provided so that superheated steam is introduced into each material passage 361. In this example, for example, a plurality of superheated steam inlets can be provided in each passage partition wall 363. Also, a vent for superheated steam may be provided.

[0145] As described above, the superheated steam that heats the molding material Mm in the material passage 61 can rapidly increase the temperature of the molding material Mm. On the other hand, when the molding material Mm heated by the superheated steam becomes lower in temperature than, for example, 100° C., condensation may occur.

[0146] In order to remove moisture due to such condensation, etc., and to dry or further heat the molding material Mm that has passed through the material passage 61 and been heated by superheated steam, the preheating device 60 of this embodiment further includes a material feed passage 22 through which the molding material Mm passes after being heated by superheated steam and passing through the material passage 61, and a heater 24 that heats the molding material Mm passing through the material feed passage 22, as shown in Fig. 23. In this embodiment, the molding material Mm passes through the above-mentioned material passage 61 in the direction of the rotation axis, and then falls into the material feed passage 22 from the passage outlet 61c of the material passage 61 due to its own weight, and passes through the material feed passage 22. Here, the material passing direction in the material passage 61 is perpendicular to the material passing direction (the up and down direction in Fig. 23) in which the molding material Mm passes through the material feed passage 22, and the molding material Mm passes through the material feed passage 22 in the vertical direction.

[0147] The material feed passage 22 has a pair of passage forming members 23 arranged opposite each other to define the material feed passage 22 between them. The heater 24 is arranged outside the material feed passage 22 in the passage width direction separated by the passage forming member 23. The passage forming member 23 and the heater 24 have a function of drying the molding material Mm that has been heated by superheated steam and passed through the material passage 61, and also have a function of further heating the molding material Mm. The passage width direction here means the alignment direction of the passage forming members 23 arranged in parallel with each other, and means a direction perpendicular to the material passing direction in the material feed passage 22 (the left-right direction in FIG. 23). In the illustrated embodiment, the material feed passage 22, the passage forming member 23, and the heater 24 are accommodated and arranged inside a box-shaped housing 25 made of a heat insulating material or the like.

[0148] At least one of the pair of path forming members 23 that define the material feed path 22 can be movable, so that the material feed path 22 is configured to be adjustable in its path width, which is the distance between the pair of path forming members 23. At least one of the path forming members 23 may be moved in the path width direction, for example, manually by a user placing a spacer between the path forming member 23 and its mounting location inside the housing 25, or automatically by using a motor or other actuator. By making the path width of the material feed path 22 adjustable, it is possible to set an appropriate path width according to each of the various molding materials Mm having various dimensions and shapes. For example, as shown in FIG. 23, when the path width is set to a value that allows one piece of molding material Mm to pass through, the molding material Mm passes through the material feed path 22 in a substantially aligned position, and at this time, most of the molding material Mm is effectively heated by the heater 24 on the outer side of the path width direction of the path forming member 23.

[0149] It is preferable that the passage width of the material feed passage 22 is equal to or greater than the length of one piece of molding material Mm and less than the length of two pieces of molding material Mm. In this case, since the material feed passage 22 prevents a plurality of pieces of molding material Mm from overlapping in the passage width direction, it is possible to heat many of the molding materials Mm more effectively.

[0150] A supply container 26 such as a hopper is provided on the lower surface of the housing 25 at the tip end (lower end side in FIG. 23) of the material feed passage 22 in the material passing direction. In the illustrated example, the supply container 26 has, for example, a truncated cone-shaped portion 26a whose inner and outer shapes are both truncated cones, and a cylindrical portion 26b formed at the end of the small diameter side of the truncated cone-shaped portion 26a. The supply container 26 preferably includes a thermal insulator, for example, by making the peripheral wall of the supply container 26 out of a thermal insulator or by covering the surface of the peripheral wall with a thermal insulator. The supply container 26 receives the molding material Mm that has passed through the material feed passage 22 in the truncated cone-shaped portion 26a, and then supplies the molding material Mm to the inside of the cylinder 11 through the cylindrical portion 26b beyond the truncated cone-shaped portion 26a. An opening 26c having a width approximately the same as that of the material feed passage 22 is formed at the end of the truncated cone-shaped portion 26a, and the molding material Mm that has passed through the material feed passage 22 enters the supply container 26 from the opening 26c.

[0151] In the illustrated example, the molding material Mm passes through the material feed passage 22 and the supply container 26, and is then supplied to the inside of the cylinder 11. In other words, the molding material Mm preheated by the preheating device 60 is supplied to the inside of the cylinder 11. However, the shape of the supply container 26 is not limited to this, and can be changed as appropriate, and the supply container 26 may be omitted. If the supply container 26 is omitted, a housing is placed on the cylinder, and the tip side of the material feed passage in the material passing direction is directly connected to the supply port of the cylinder. In this case, the molding material is supplied to the inside of the cylinder immediately after passing through the material feed passage.

[0152] Here, the heater 24 can be disposed on only one side of the material feed passage 22, outside one of the passage forming members 23 in the passage width direction, but in this embodiment, the heater 24 is disposed on both sides of the material feed passage 22, outside each of the passage forming members 23 in the passage width direction. This allows the molding material Mm to be heated quickly by the heaters 24 on both sides, so that the molding material Mm can be effectively heated even if the passing speed of the molding material Mm through the material feed passage 22 is made relatively fast. The conditions of the heater 24, etc. are set so that the molding material Mm reaches a desired temperature at the tip end of the material feed passage 22 in the material passing direction.

[0153] The heater 24 may be of any heating type as long as it can heat the molding material Mm through the passage forming member 23. For example, a hot air heating type heater that supplies a heated gas such as high-temperature air, an electric heater such as a high-frequency dielectric heater, an infrared heating type heater such as a halogen lamp or a ceramic heater, a laser heating type heater, etc. can be used. When the heater 24 is an infrared heating type heater or a laser heating type heater, the passage forming member 23 can be made of a translucent or transparent material such as glass through which light or a laser can pass. The arrangement of the heater 24 is not limited to the example shown in the figure, and the heater 24 may be arranged outside the housing 25 and hot air may be flowed through the material feed passage 22.

[0154] The illustrated preheating device 60 has, as an example, a heater 24 including a hot air heater. Specifically, the hot air heater can be one that obtains hot air by, for example, heating compressed air sent from a compressor with a sheathed heater or the like. The temperature of the hot air can be adjusted by changing the output of the sheathed heater. The hot air heater is preferable in that it can more effectively dry the molding material Mm.

[0155] In this case, the passage forming member 23 may have a plurality of ventilation holes penetrating the passage forming member 23 in the passage width direction in order to pass the heated gas sent from the hot air heater through the material feed passage 22. As a result, the heated gas from the heater 24 flows into the material feed passage 22 through the ventilation holes of the passage forming member 23, so that the molding material Mm in the material feed passage 22 can be heated by the heated gas.

[0156] Specifically, the passage forming member 23 may be a plate-like member in which a plurality of ventilation holes 23b are formed in a metal plate material 23a by press working, etc., as shown in Fig. 28(a), such as a so-called punched metal. In this case, by adjusting the processing mode, etc., a plurality of regularly arranged ventilation holes 23b can be formed in the plate material 23a.

[0157] Alternatively, as shown in FIG. 28(b), the passage forming member 23 may be a mesh member in which, for example, wires 23c are arranged in a lattice pattern, and a plurality of vent holes 23b are provided between the wires, each having a square or other polygonal shape when viewed from the front. If the thickness of such a mesh member is thin and the mesh member does not have the strength required to form the material feed passage 22 with the passage forming member 23, the mesh member and a reinforcing member may be overlapped to form the passage forming member 23. The reinforcing member may have various shapes, such as a honeycomb shape or a lattice shape, as long as it can pass the heated gas. For example, the mesh of the reinforcing member may be coarser than that of the mesh member. In the illustrated mesh member, a plurality of vent holes 23b are regularly arranged in the vertical direction (up and down direction in FIG. 28(b)) and the horizontal direction (left and right direction in FIG. 28(b)) perpendicular to the vertical direction when viewed from the front.

[0158] For example, when the material feed passage 22 is defined by a mesh-like passage forming member 23, as shown in Fig. 29, a plurality of molding materials Mm spreads out in the lateral direction of the passage forming member 23 and moves in the material passing direction, which is the vertical direction of the passage forming member 23, as shown by the arrows in the figure. Note that between each pair of passage forming members 23, on each side of the material feed passage 22 in the lateral direction of the passage forming member 23, passage dividing members 22a, such as square rods, are arranged to divide the area of ​​the material feed passage 22 in the lateral direction of the passage forming member 23.

[0159] When the air holes 23b are evenly distributed and regularly arranged in a front view like the above-mentioned mesh-like or plate-like passage forming member 23, the heated gas from the heater 24, which is a hot air heater, can be fed evenly to the material feed passage 22 in the vertical and horizontal directions of the passage forming member 23. This allows the heated gas to be blown onto many of the multiple molding materials Mm passing through the material feed passage 22, and the molding materials Mm can be heated even more effectively.

[0160] In this embodiment, as the plasticization of the molding material by the screw 12 inside the cylinder 11 progresses, the molding material Mm is supplied from the supply container 26 to the inside of the cylinder 11. Accordingly, the molding material Mm that has passed through the material passage 61 passes through the material feed passage 22, is heated by the heater 24, and then is fed into the supply container 26. In this case, the speed of the molding material Mm passing through the material feed passage 22 may depend on the speed of plasticization of the molding material Mm inside the cylinder 11, but the passing speed of the molding material Mm can also be adjusted by changing the passage width as described above. In addition, in order to adjust the speed at which the molding material Mm passes through the material feed passage 22 and the degree of heating of the molding material Mm that is influenced by the speed, a screw-shaped feeder or other supply adjuster that adjusts the supply of the molding material Mm from the material feed passage 22 to the supply container 26 may be provided between the material feed passage 22 and the supply container 26, although not shown in the figure. Although not shown, there may be a mechanism for changing the position of the material feed passage 22 while keeping the passage width constant. By changing the position of the material feed passage 22, the amount of molding material Mm passing through per unit time can be adjusted.

[0161] Incidentally, in a mesh-like or plate-like passage forming member 23 having a plurality of ventilation holes 23b, the molding material Mm may get caught in the ventilation holes 23b in the material feed passage 22 formed thereby, causing the molding material Mm to become clogged or accumulate in at least a portion of the lateral direction of the passage forming member 23. The accumulation of the molding material Mm in the material feed passage 22 may lead to excessive heating of the molding material Mm, and ultimately to melting of the molding material Mm. Therefore, it is preferable to provide the preheating device 60 with a retention prevention mechanism that prevents the molding material Mm from retaining in the material feed passage 22.

[0162] 30 to 33, the retention prevention mechanism can be a drive unit that displaces at least one of a pair of passage forming members 23 continuously during operation of the injection molding machine, or intermittently only when necessary, to change the relative position and / or orientation of one passage forming member 23 with respect to the other passage forming member 23. Note that illustration of the drive source is omitted here.

[0163] As shown in Fig. 30, square bar-shaped movable members 22b are provided on both lateral sides of one of the passage forming members 23, outside the passage width direction of the passage forming member 23. While the molding material Mm is passing through the material feed passage 22, the movable members 22b move one of the passage forming members 23 in the lateral direction of the passage forming member 23, as shown by the arrows in Figs. 30(b) and (c), thereby changing the relative position of one of the passage forming members 23 with respect to the other passage forming member 23. As a result, even if the molding material Mm gets caught in the ventilation hole 23b, the movement of one of the passage forming members 23 releases the catch, preventing the molding material Mm from stagnation. Furthermore, one of the passage forming members 23 may be moved not in the lateral direction of the passage forming member 23 but in the vertical direction (up and down direction) parallel to the material passing direction.

[0164] In the retention prevention mechanism shown in Fig. 31, a square bar-shaped movable member 22b is provided on each of both vertical ends of one of the passage forming members 23, outside the passage width direction of the passage forming member 23. As shown in Figs. 31(b) and (c), this retention prevention mechanism moves one of the passage forming members 23 in the passage width direction by the movable member 22b, and changes the relative position of one of the passage forming members 23 with respect to the other passage forming member 23, while the molding material Mm is passing through. At this time, the passage width of the material feed passage 22 increases and decreases slightly. The retention prevention mechanism in Fig. 31 can also be used as a mechanism for moving the passage forming member 23 to adjust the passage width as described above.

[0165] The retention prevention mechanism in Fig. 32 has a square bar-shaped movable member 22b provided on each of both vertical ends of one of the passage forming members 23 on the outer side of the passage width direction of the passage forming member 23, and a cylindrical or other fulcrum member 22c extending in the lateral direction of the passage forming member 23, which is sandwiched between the passage forming member 23 and the passage dividing member 22a at an intermediate position such as the center position in the material passing direction of the material feed passage 22. Here, the fulcrum member 22c is attached to the passage dividing member 22a. In this case, as shown in Figs. 32(b) and (c), when the movable members 22b are moved in mutually opposite directions in the passage width direction, one of the passage forming members 23 is pivotally displaced around the fulcrum member 22c and changes its orientation so as to be oblique to the other passage forming member 23. More specifically, when one end of one passage forming member 23 in the vertical direction approaches or moves away from the other passage forming member 23, the orientation of one passage forming member 23 changes so that the other end of one passage forming member 23 in the vertical direction approaches or moves away from the other passage forming member 23. Accordingly, the passage width of the material feed passage 22 may not be constant in the material passing direction. Even with such a retention prevention mechanism, retention of the molding material Mm can be effectively prevented.

[0166] The retention prevention mechanism in Fig. 33 has a configuration similar to that in Fig. 32, but the fulcrum member 22c is fixed and attached to one of the passage forming members 23, not to the passage partition member 22a. In Fig. 33, by driving the fulcrum member 22c to rotate without moving the movable member 22b, one of the passage forming members 23 rotates and displaces around the fulcrum member 22c together with the fulcrum member 22c, and the orientation relative to the other passage forming member 23 changes in a manner substantially similar to that in Fig. 32.

[0167] Alternatively, as shown in Fig. 34(a), the retention prevention mechanism may be configured with an impact applying part 28 that is arranged on the outside of at least one of the passage forming members 23 in the passage width direction and strikes the passage forming member 23 at a predetermined period or the like. The illustrated impact applying part 28 includes a plate-shaped member 28b that is arranged parallel to the other passage forming member 23 on the outside of the other passage forming member 23 in the passage width direction and has one or more through holes 28a formed therein, and one or more pin-shaped members 28c that are arranged through the through holes 28a of the plate-shaped member 28b and displace toward or away from the other passage forming member 23. A similar impact applying part 28 may also be provided on the outside of one of the passage forming members 23 in the passage width direction.

[0168] In addition, the retention prevention mechanism may be configured as shown in Figure 34(b) by a vibration imparting unit 29 such as one or more vibrators attached to at least one of the passage forming members 23, for example the outer surface in the passage width direction of the other passage forming member 23, and imparting vibrations to the passage forming member 23.

[0169] As shown in Fig. 35(a), the retention prevention mechanism may be a blower 30 that is disposed on at least one outer side of the passage width direction of the passage forming member 23 and blows gas at different flow rates through the vent holes 23b of the passage forming member 23 to the molding material Mm in the material feed passage 22. As shown in Fig. 35(b) or (c), the blower 30 changes the flow rate of the gas sent to the molding material Mm in the material feed passage 22 over time, thereby allowing the gas to be blown to the molding material Mm with varying strength. When sending gas from the blower 30 to the molding material Mm, a period of zero flow rate and a period of high flow rate may be repeated periodically as shown in Fig. 35(b), or a period of low flow rate and a period of high flow rate may be repeated periodically as shown in Fig. 35(c). Although the blower 30 can be provided separately as a retention prevention mechanism, the heater 24, which is the above-mentioned hot air heating type heater, can be used as the blower 30 and the heater 24 can also be used as a retention prevention mechanism. When the heater 24 is used both as a preheating mechanism and a retention prevention mechanism, the gas from the blower 30 corresponds to the heated gas from the heater 24.

[0170] 30 to 35, the retention prevention mechanisms described above can be used alone or in combination in the preheating device 60. In other words, the preheating device 60 can include one or more of the retention prevention mechanisms shown in FIGS.

[0171] Moreover, the preheating device 60 is preferably provided with a retention detection mechanism that detects retention of the molding material Mm in the material feed passage 22. The retention detection mechanism may be, for example, a sensor that detects retention by temperature, an image taken by a camera, infrared rays, a laser, or the like.

[0172] Such a sensor of the retention detection mechanism is preferably provided at a portion on the leading end side of the material feed passage 22 in the material passing direction, that is, at a location near the material feed passage 22 before the supply container 26 in the material passing direction. More specifically, as shown in Fig. 29, such a sensor 23d can be provided, for example, at a plurality of sensors spaced apart from one another in the lateral direction of the passage forming member 23 on the outer side of the passage width direction of the passage forming member 23 at the leading end side of the material feed passage 22 in the material passing direction. This makes it possible to find a location where retention of the molding material Mm occurs in the lateral direction of the passage forming member 23 at an early stage.

[0173] If the sensor 23d of the retention detection mechanism is a temperature sensor, it is preferable to arrange the temperature sensor so that it can measure the temperature of the molding material Mm located at the tip end portion in the material passing direction of the material feed passage 22. The temperature of the molding material Mm referred to here may be the temperature of the molding material Mm itself, the temperature of the passage forming member 23, or the temperature in the space within the ventilation hole 23b of the passage forming member 23. In the case of a contact type temperature sensor, to measure the temperature of the molding material Mm itself or the temperature of the passage forming member 23, for example, the temperature sensor is passed through the ventilation hole 23b of the passage forming member 23 and arranged so that its tip is in contact with the molding material Mm, or so that the tip of the temperature sensor is in contact with the passage forming member 23.

[0174] The aforementioned retention prevention mechanism can be operated continuously at all times while the injection molding machine is operating, or can be operated intermittently at specific times, such as when the retention detection mechanism detects retention of molding material Mm in the material feed passage 22.

[0175] Although not shown in the drawings, a plurality of material feed passages may be provided. In this case, the area of ​​each material feed passage can be reduced, and the preheating device can be made compact. For example, when two or more material feed passages arranged in parallel with each other are provided, it is preferable to provide heaters on both sides of each material feed passage in the passage width direction from the viewpoint of realizing rapid and uniform preheating of the molding material Mm.

[0176] On the other hand, as in the embodiment shown in FIG. 36, the above-mentioned material feed passage may be omitted, and the passage outlet 61c of the material passage 61 may be directly connected to the opening 26c of the supply container 26. The preheating device 260 in FIG. 36 has a substantially similar configuration to that in FIG. 23, except that the housing 25 and its internal structure (i.e., the material feed passage 22, the passage forming member 23, and the heater 24) of the preheating device 60 in FIG. 23 are omitted. In the preheating device 260 shown in FIG. 36, the molding material Mm that has passed through the material passage 61 while being heated by the superheated steam Ss is supplied to the inside of the cylinder 11 through the supply container 26. In this case, it is also possible to provide a hot air heater (not shown) at the passage outlet 61c of the material passage 61, and dry the molding material Mm there. Although not shown, it is also possible to omit the supply container 26 and connect the passage outlet of the material passage to the supply port of the cylinder.

[0177] Fig. 37 shows a preheating device 460 according to still another embodiment. The preheating device 460 in Fig. 37 does not have a conveying mechanism such as a preheating screw, and the molding material Mm passes through a material passage 461 while dropping downward due to its own weight. Here, the material passage direction of the material passage 461 is parallel to the vertical direction, similar to the material passage direction of the material feed passage 22, but the material passage 461 can also be inclined with respect to the vertical direction as long as the molding material Mm can pass through it. In the preheating device 460, for example, a plurality of superheated steam inlets 462 are provided in a passage partition wall portion 463 around the material passage 461. The superheated steam Ss is sent from the superheated steam inlets 462 into the material passage 461 to heat the molding material Mm.

[0178] Even in a preheating device 460 having such a material passage 461 and a superheated steam inlet 462, the housing 25 and its internal structure (i.e., the material feed passage 22, the passage forming member 23 and the heater 24), and / or the supply container 26 may be omitted.

[0179] (Control of pre-heating device) The above-described preheating devices 60, 360, 460 can be controlled, for example, as described below. Note that, here, as an example, the control of the preheating device 60 out of the preheating devices 60, 360, 460 will be described.

[0180] As described above, when the preheating device 60 is in use, the temperature of the molding material Mm at the tip end of the material feed passage 22 in the material passing direction is constantly monitored by the sensor 23d, or the like, provided as a retention detection mechanism or the like at the tip end of the material feed passage 22 in the material passing direction. Information on the temperature of the molding material Mm measured in this way is transmitted to, for example, the control unit of the injection molding machine.

[0181] During normal operation, as shown in Fig. 38(a), the molding material Mm is heated by the heating gas Gh or the like, and the temperature increases as it proceeds in the material passing direction through the material feed passage 22. At this time, the heating temperature of the heater 24 and other conditions may be set so that the temperature of the molding material Mm is less than a predetermined allowable upper limit value Tu that is lower than the melting point Tm of the molding material Mm. The allowable upper limit value Tu may be set to a temperature, for example, about 10°C lower than the melting point Tm.

[0182] Here, if the operation of the injection molding machine stops for some reason, or if the sensor 23d serving as a retention detection mechanism detects retention of molding material Mm in the material feed passage 22 regardless of whether the retention prevention mechanism is operating or not, the temperature of the molding material Mm may rise in the material feed passage 22 as shown in Fig. 38(b). If the temperature of the molding material Mm approaches the melting point Tm or becomes equal to or higher than the melting point Tm, there is a concern that the molding materials Mm may melt and fuse together with each other or with the passage forming member 23, making it impossible for the molding material Mm to pass through the material feed passage 22.

[0183] To prevent this, when the operation of the injection molding machine stops or when the retention of the molding material Mm in the material feed passage 22 is detected (for example, when retention of the molding material Mm is detected while the retention prevention mechanism is continuously operating, or when retention of the molding material Mm is detected in the material feed passage 22 while the retention prevention mechanism is not operating, and the retention is not eliminated even when the retention prevention mechanism is operated in response to that, and the retention is still detected), an operation stop signal or retention detection signal is sent to the control unit. In response to this, the control unit sends a heating stop signal to the preheating device 60 to stop heating the molding material Mm by the heater 24, and the preheating device 60 stops heating the molding material Mm by the heater 24. That is, the preheating device 60 stops heating the molding material Mm by the heater 24 based on information on the stop of the operation of the injection molding machine and / or information on the retention of the molding material Mm in the material feed passage 22.

[0184] The operation of the injection molding machine may be stopped, for example, when production is completed, when an abnormality is detected, when an emergency stop button is pressed, etc. Such stops can be detected by various sensors, etc.

[0185] Even when heating of the molding material Mm by the heater 24 is stopped, residual heat may cause the temperature of the molding material Mm to rise in the material feed passage 22. Therefore, when the temperature of the molding material Mm measured by the temperature sensor meets a predetermined standard after heating by the heater 24 is stopped, the molding material Mm in the material feed passage 22 is cooled, for example, by a cooling gas Gc, as shown in Fig. 38(c).

[0186] The above-mentioned predetermined standard for starting cooling of the molding material Mm can be a standard determined by comparing the actual measured value of the temperature of the molding material Mm with the allowable upper limit Tu. Specifically, the cooling of the molding material Mm can be started when the actual measured value of the temperature of the molding material Mm reaches the allowable upper limit Tu. Alternatively, the above-mentioned predetermined standard can be determined by estimating the amount of temperature rise that the molding material Mm may rise to in the future from the difference between the temperature of the molding material Mm and the ambient temperature of the preheating device 60, and comparing the estimated amount of temperature rise with the allowable upper limit Tu. Alternatively, the above-mentioned predetermined standard can be determined by comparing the estimated value of the temperature of the molding material Mm with the allowable upper limit Tu. In other words, the preheating device 60 cools the molding material Mm in the material feed passage 22 based on information about the temperature of the molding material Mm.

[0187] The cooling of the molding material Mm can be achieved by configuring the heater 24 as a hot air heating type heater or the blower section 30 to be capable of blowing room temperature gas such as cold air or cooling gas Gc. In addition, a cooling section for cooling the molding material Mm in the material feed passage 22 may be provided in the pre-heating device 60, separate from the heater 24 and the blower section 30. This effectively prevents the material feed passage 22 from being blocked by the melting of the molding material Mm.

[0188] An example of the above-mentioned control is shown in FIG. 39. In FIG. 39, first, the molding material Mm is passed through the preheating device 60 and then supplied into the cylinder 11 to form a molded product. If the operation of the injection molding machine stops during this time, the heater 24 is stopped. Even if the operation of the injection molding machine is not stopped, for example, if the molding material Mm is stuck in the material feed passage 22 while the retention prevention mechanism is continuously operating, the heater 24 is stopped. Note that if the operation of the injection molding machine is not stopped and the retention of the molding material Mm occurs in the material feed passage 22 while the retention prevention mechanism is stopped, the retention prevention mechanism is first operated, and if the retention is not resolved, the heater 24 is stopped. If the operation of the injection molding machine is not stopped and the retention of the molding material Mm does not occur, molding is continued. Note that the confirmation of whether the operation of the injection molding machine has stopped and the confirmation of whether the retention of the molding material Mm has occurred may be switched so that the order is reversed, or only one of them may be confirmed.

[0189] Next, after stopping the heater 24, it is confirmed whether or not the temperature of the molding material Mm is equal to or higher than the allowable upper limit. If the temperature of the molding material Mm is equal to or higher than the allowable upper limit, the molding material Mm is cooled, and it is confirmed again whether or not the temperature of the molding material Mm is equal to or higher than the allowable upper limit. When the temperature of the molding material Mm is below the allowable upper limit, it is determined whether or not molding should be resumed. When it is determined that molding may be resumed, molding is resumed.

[0190] (injection device) An injection device 1 to which the above-mentioned preheating device 60 and the like can be applied mainly comprises, as illustrated in FIG. 22 , the preheating device 60, a cylinder 11 which melts the molding material supplied from the preheating device 60 therein, a screw 12 which is rotated inside the cylinder 11 to plasticize the molding material, a metering motor 31 arranged on the rear side in the direction of the rotation axis of the screw 12 (the right side in FIG. 22 ), and an injection motor 41 arranged further rearward of the metering motor 31.

[0191] A heater 13 is arranged around the cylinder 11 to heat the molding material plasticized by the screw 12 inside the cylinder 11. The cylinder 11 has a tip portion 14 with smaller inner and outer diameters at the tip side in the rotation axis direction (left side in FIG. 22), and heaters 13 are also arranged around the tip portion 14. In addition, a through-hole-shaped supply port 11a is provided at the rear end side in the rotation axis direction of the cylinder 11, and the above-mentioned preheating device 60 is attached thereto.

[0192] The metering motor 31 and the injection motor 41 are fixed to the rear surfaces of the rear ends in the rotation axis direction of two motor support plates 32, 42, which are arranged at a distance from each other in an upright position on the slide base 101. The screw 12 is driven to rotate by the metering motor 31, and driven to move forward and backward by the injection motor 41. The two motor support plates 32, 42 are connected to each other by rods 51 at multiple points (for example, four points) around the metering motor 31.

[0193] The metering motor 31 mainly includes a rotor 33, a stator 34 arranged around the rotor 33, and a stator frame 35 that surrounds the rotor 33 and the stator 34 and has the stator 34 provided on its inner surface. The rotor 33 of the metering motor 31 is supported by bearings 33a inside the stator frame 35 at each end in the direction of its rotation axis. The rotor 33 is splined around a metering spline shaft 36, and the metering spline shaft 36 is connected to a screw mounting portion 37 to which the screw 12 is attached. At the rear end in the direction of the rotation axis of the outer circumferential surface of the metering spline shaft 36, one or more keys 36a corresponding to the key grooves provided on the inner circumferential surface of the rotor 33 are formed. This allows a rotational driving force to be transmitted from the metering motor 31 to the screw 12, thereby rotating the screw 12.

[0194] The injection motor 41 mainly includes a rotor 43, a stator 44 arranged around the rotor 43, and a stator frame 45 that is provided around the rotor 43 and the stator 44 and has the stator 44 on its inner surface. The rotor 43 is supported by bearings 43a inside the stator frame 45 at each end in the direction of its rotation axis. In the injection motor 41, the rotor 43 is connected to a drive shaft. More specifically, the drive shaft includes an injection spline shaft 46 splined at a groove 43b provided on the inner periphery of the cylindrical rotor 43, a threaded shaft 48 connected to the injection spline shaft 46, and a rotating shaft 50 rotatably attached to the inside of the metering spline shaft 36 via a bearing 49. A threaded nut 47 that screws onto the threaded shaft 48 is attached to the motor support plate 42 via a pressure detector 38, which will be described later. With this structure, the rotational driving force of the injection motor 41 is converted into a linear driving force in the direction of the rotation axis of the screw 12 and transmitted to the screw 12 .

[0195] A pressure detector 38 is disposed between the stator frame 45 of the injection motor 41 and the motor support plate 42. The pressure detector 38 is attached to the motor support plate 42 and the screw nut 47, and detects the load acting on the pressure detector 38 in the transmission path of the driving force from the injection motor 41 to the screw 12. A cylindrical portion 39 is provided between the pressure detector 38 and the stator frame 45. Further, an encoder 45a that is connected to the rotor 43 by a shaft portion 45b and detects the rotation of the rotor 43 is provided on the rear end surface of the stator frame 45 of the injection motor 41, which is located on the opposite side to the drive shaft in the rotation axis direction.

[0196] To give an example of a molding process using an injection molding machine equipped with such an injection unit 1, a mold clamping process is performed in which a mold unit (not shown) is closed to clamp the mold, with a predetermined amount of molding material already accumulated and placed inside the cylinder 11 in the latter half of the previous molding process. Next, a filling process is performed in which the molding material is injected into the mold unit by advancing the screw 12 to fill the cavity in the mold unit with the molding material, and a pressure holding process is performed in which the molding material inside the tip 14 of the cylinder 11 is maintained at a predetermined pressure by further advancing the screw 12.

[0197] Then, a cooling process is performed in which the molding material filled in the mold device is cooled and hardened to obtain a molded product. At this time, a measuring process is performed in which the molding material separately supplied from the preheating device 60 into the cylinder 11 is melted while being sent toward the tip 14 of the cylinder 11 by the rotation of the screw 12 under heating by the heater 13, and a predetermined amount of the molding material is placed at the tip 14.

[0198] Here, in this embodiment, the molding material supplied into the cylinder 11 has already been heated to an appropriate temperature by the preheating device 60. Therefore, even if the screw 12 is rotated at high speed and the molding material is sent to the tip 14 of the cylinder 11 in a short period of time, the molding material can be sufficiently plasticized. This shortens the time required for the molding material to accumulate at the tip 14 of the cylinder 11, thereby realizing a shortened molding cycle.

[0199] After that, the mold assembly is opened to bring it into an open state, and an ejection step is performed in which the molded product is ejected from the mold assembly by an ejector device or the like.

[0200] [Fourth Invention] In this embodiment, the preheating device 21 is for preheating the molding material, and by being provided in an injection device 1 as illustrated in FIG. 40, the preheated molding material can be supplied to the injection device 1. The injection device 1 illustrated in FIG. 40 is an injection molding machine, and is disposed, for example, on a slide base 101 of a moving device that moves the injection device 1 forward and backward, and injects the molding material into a mold device. The injection device 1 can be provided with the preheating device 21 and a cylinder 11 to which the molding material preheated by the preheating device is supplied and melts the molding material inside. The illustrated injection device 1 further includes a screw 12 that is rotated and driven inside the cylinder 11 to plasticize the molding material, a heater 13 that is provided around the cylinder 11 to heat the molding material inside the cylinder 11, and the detailed structure of the injection device 1 will be described later.

[0201] (Preheating device) The preheating device 21 is attached to the rear end of the cylinder 11 on the opposite side to the tip end 14 that injects the molding material, in the direction of the rotation axis of the screw 12 of the injection device 1 (left and right direction in Fig. 40). More specifically, the preheating device 21 is connected to a through-hole-like supply port 11a provided on a part of the circumference of the rear end of the cylinder 11, as shown in Fig. 41, and supplies molding material Mm, such as resin pellets having substantially spherical or cylindrical shapes or other shapes, to the supply port 11a.

[0202] In this first embodiment, the preheating device 21 has a material feed passage 22 through which the molding material Mm passes, a heating section 24 that heats the molding material Mm passing through the material feed passage 22, and a cooling section (not shown in Figure 41) that cools the molding material Mm passing through the material feed passage 22.

[0203] In the preheating device 21 having such a configuration, the molding material Mm to be supplied to the inside of the cylinder 11 can be preheated before being supplied. As a result, the preheated molding material Mm is supplied to the inside of the cylinder 11 through the supply port 11a, and then sufficiently melts within a short time inside the cylinder 11 and is injected from the tip of the cylinder 11, thereby shortening the molding cycle. Even if the injection device stops during injection molding and the movement of the molding material Mm stops in the material feed passage 22, the molding material Mm passing through the material feed passage 22 can be cooled by the cooling unit, so that the molding material Mm can be prevented from melting and fusing due to residual heat in the material feed passage 22.

[0204] (Control of pre-heating device) Here, the preheating device 21 may further include a control unit that controls the heating unit 24 and / or the cooling unit, as shown in the block diagram of Fig. 42. More specifically, as shown in Fig. 42, the control unit may control the heating unit 24 and / or the cooling unit based on signals obtained by an operation state detection mechanism, a retention detection mechanism, and / or a temperature information detection mechanism, which will be described later. The control of the preheating device 21 by the control unit can be carried out, for example, as described below. In addition, when the injection device 1 is equipped with a pre-heating device 21, the control unit for controlling the operation of the injection device 1 equipped in the injection device 1 can also serve as the control unit that controls the above-mentioned heating unit 24 and / or cooling unit.

[0205] When the preheating device 21 is in use, a temperature sensor or the like provided at, for example, the tip end of the material feed passage 22 in the material passing direction constantly monitors the temperature of the molding material Mm at the tip end of the material feed passage 22 in the material passing direction. Information on the temperature of the molding material Mm measured in this way is transmitted to, for example, a control unit of the preheating device 21.

[0206] During normal operation, as shown in Fig. 43(a), the molding material Mm is heated by the heating gas Gh generated by the heating unit 24 and the temperature increases as it proceeds in the material passing direction through the material feed passage 22. At this time, the heating temperature of the heating unit 24 and other conditions may be set so that the temperature of the molding material Mm is less than a predetermined allowable upper limit value Tu that is lower than the melting point Tm of the molding material Mm. The allowable upper limit value Tu may be set to a temperature, for example, about 10°C lower than the melting point Tm.

[0207] Here, if the operation of the injection molding machine stops for some reason, or if the molding material Mm becomes stagnant in the material feed passage 22, the movement of the molding material Mm may stop in the material feed passage 22. At this time, the temperature of the molding material Mm may rise in the material feed passage 22, as shown in Fig. 43(b). If the temperature of the molding material Mm approaches the melting point Tm or exceeds the melting point Tm, there is a concern that the molding materials Mm may melt and fuse together or the molding material Mm may melt and fuse to the passage forming member 23, preventing the molding material Mm from passing through the material feed passage 22. As described later, the preheating devices 21 and 60 of the first and second embodiments can be equipped with a retention prevention mechanism, and the above-mentioned "when the molding material Mm is retained in the material feed passage 22" also includes the case where the molding material Mm is retained in the material feed passage 22, regardless of whether the retention prevention mechanism is operating at that time.

[0208] To prevent this, the preheating device 21 is equipped with an operation state detection mechanism that detects the operation state of the injection device 1 and / or a retention detection mechanism that detects retention of the molding material Mm in the material feed passage 22. When the operation state detection mechanism detects information regarding the stop of the operation of the injection device 1 or when the retention detection mechanism detects information regarding retention of the molding material Mm, the detection signal, specifically, an operation stop signal for the injection device 1 or a retention detection signal for the molding material Mm, is sent to the control unit. In response to this, the control unit controls the heating unit 24. Specifically, the control unit sends a heating stop signal to the preheating device 21 to stop heating the molding material Mm by the heating unit 24, and the preheating device 21 stops heating the molding material Mm by the heating unit 24. As will be described later, in the case where the preheating devices 21, 60 of the first and second embodiments are equipped with a retention prevention mechanism, the above-mentioned "when the retention detection mechanism detects information regarding retention of the molding material Mm" also includes, for example, a case where retention of the molding material Mm is detected while the retention prevention mechanism is continuously operating, or a case where retention of the molding material Mm is detected in the material feed passage 22 while the retention prevention mechanism is not operating, and even if the retention prevention mechanism is operated in response to this, the retention is not resolved and the retention is still detected.

[0209] In this way, the pre-heating device 21 is equipped with an operation status detection mechanism and / or a retention detection mechanism, and the control unit controls the heating unit 24 based on information detected by the operation status detection mechanism and / or the retention detection mechanism, thereby making it possible to stop heating by the heating unit 24 and prevent the molding material Mm from melting and fusing due to excessive heating in the material feed passage 22. In this specification, a state in which the movement of the molding material Mm has stopped does not mean that each individual piece of molding material Mm is strictly stopped, but rather that the movement of the molding material Mm as a whole has stopped.

[0210] Furthermore, detection by the operation state detection mechanism can be performed, for example, by providing a transmitter that transmits the operation status of the injection device 1, more specifically, a transmitter that transmits the operation status of the metering motor 31 and the injection motor 41 of the injection device 1. Furthermore, the operation state detection mechanism can also detect, for example, a stop due to completion of production, a stop due to detection of an abnormality, a stop due to pressing of an emergency stop button, etc., and the above-mentioned stops can be detected by various sensors, etc. Furthermore, the detection of the accumulation of the molding material Mm in the material feed passage 22 by the accumulation detection mechanism can be performed by using a sensor that detects the accumulation of the molding material Mm in the material feed passage 22.

[0211] However, even if the heating of the molding material Mm by the heating unit 24 is stopped, the molding material Mm in the material feed passage 22 may rise due to residual heat. In order to prevent this, the preheating device 21 is provided with a temperature information detection mechanism that detects information regarding the temperature of the molding material Mm in the material feed passage 22. After the heating of the heating unit 24 is stopped, when the temperature information detection mechanism detects information regarding the temperature of the molding material Mm in the material feed passage 22, specifically, when the temperature information detection mechanism detects information that the temperature of the molding material Mm measured by a temperature sensor meets a predetermined standard, the detection signal is transmitted to the control unit. In response to this, the control unit controls the cooling unit. Specifically, the control unit controls the cooling unit to cool the molding material Mm in the material feed passage 22, for example, by cooling gas Gc, as shown in FIG. 43(c).

[0212] The above-mentioned predetermined standard for starting cooling of the molding material Mm can be a standard determined by comparing the actual measured value of the temperature of the molding material Mm with the allowable upper limit Tu. Specifically, the cooling of the molding material Mm can be started when the actual measured value of the temperature of the molding material Mm reaches the allowable upper limit Tu. Alternatively, the above-mentioned predetermined standard can be determined by estimating the amount of temperature rise that the molding material Mm may rise to in the future from the difference between the temperature of the molding material Mm and the ambient temperature of the material feed passage 22, and comparing the estimated amount of temperature rise with the allowable upper limit Tu. Alternatively, the above-mentioned predetermined standard can be determined by comparing the estimated value of the temperature of the molding material Mm with the allowable upper limit Tu. The information that at least one of the above standards has been met is included in the information on the temperature of the molding material Mm in the material feed passage 22 detected by the temperature information detection mechanism.

[0213] The cooling by the cooling unit only needs to lower the temperature of the molding material Mm, and the cooling medium applied to the molding material Mm may be not only cold air but also air with a temperature lower than that of the molding material Mm, for example, air at room temperature. The cooling unit may be provided in the preheating device 21, but can be realized by configuring the heating unit 24 to be able to send room temperature air such as cold air or a cooling gas Gc. This effectively prevents the material feed passage 22 from being blocked by the melting of the molding material Mm.

[0214] An example of the above-mentioned control is shown in FIG. 44. In FIG. 44, first, the molding material Mm is passed through the preheating device 21 and then supplied into the cylinder 11 to form a molded product. During this time, if the operation state detection mechanism detects information regarding the stop of the operation of the injection device 1, for example, if the operation of the injection device 1 is stopped, the heating unit 24 is stopped by control by the control unit. Even if the operation of the injection device 1 is not stopped, if the retention detection mechanism detects information regarding the retention of the molding material Mm, for example, if retention of the molding material Mm occurs in the material feed passage 22, the heating unit 24 is stopped by control by the control unit. If the operation of the injection device 1 is not stopped and retention of the molding material Mm does not occur, molding is continued. Note that the confirmation of whether the operation of the injection device 1 has stopped and the confirmation of whether retention of the molding material Mm has occurred may be switched so that the order is reversed, or only one of them may be confirmed. As described later, when the preheating devices 21, 60 of the first and second embodiments are provided with a retention prevention mechanism, the above-mentioned "when retention of the molding material Mm occurs in the material feed passage 22 even when the operation of the injection device 1 is not stopped" includes, for example, a case where retention of the molding material Mm occurs in the material feed passage 22 even if the retention prevention mechanism is continuously operating. When a retention prevention mechanism is provided, when the operation of the injection device 1 is not stopped and the operation of the retention prevention mechanism is stopped and retention of the molding material Mm occurs in the material feed passage 22, it is preferable to first operate the retention prevention mechanism, and if the retention is not resolved, to stop the heating unit 24.

[0215] Next, after stopping the heating unit 24, it is confirmed whether the temperature of the molding material Mm is equal to or higher than the allowable upper limit. In other words, when the temperature information detection mechanism detects information regarding the temperature of the molding material Mm in the material feed passage 22, for example, information that the temperature of the molding material Mm is equal to or higher than the allowable upper limit, the cooling unit is started under the control of the control unit to cool the molding material Mm. Then, it is confirmed again whether the temperature information detection mechanism is still detecting information regarding the temperature, that is, whether the temperature of the molding material Mm is equal to or higher than the allowable upper limit. If the temperature information detection mechanism does not detect any information regarding the temperature, for example, if the temperature of the molding material Mm is below the allowable upper limit, a decision is made as to whether or not molding should be resumed. If it is determined that molding may be resumed, molding is resumed.

[0216] (Preheating device of the first embodiment) Next, the preheating device of the first embodiment will be described in more detail with reference to the drawings. In the first embodiment, the preheating device 21 has a material feed passage 22 through which the molding material Mm passes, and a heating unit 24 that heats the molding material Mm passing through the material feed passage 22, as shown in FIG. 41. Here, the material feed passage 22 has a pair of passage forming members 23 that are arranged opposite each other to define the material feed passage 22 between them. The heating unit 24 is arranged outside the material feed passage 22 in the passage width direction separated by the passage forming member 23. The passage width direction here means the alignment direction of the passage forming members 23 arranged in parallel with each other, and means a direction (left and right direction in FIG. 41) perpendicular to the material passing direction (up and down direction in FIG. 41) in which the molding material Mm passes through the material feed passage 22. The material feed passage 22, the passage forming member 23, and the heating unit 24 are accommodated and arranged inside a box-shaped housing 25 made of a heat insulating material or the like.

[0217] In the preheating device 21 having such a configuration, the molding material Mm to be supplied into the cylinder 11 can be preheated before being supplied. As a result, the preheated molding material Mm is supplied into the cylinder 11 through the supply port 11a, and then sufficiently melted within a short time inside the cylinder 11 and injected from the tip of the cylinder 11, thereby realizing a shortened molding cycle.

[0218] In this embodiment, at least one of the pair of path forming members 23 that define the material feed path 22 is movable as shown by the arrow in Fig. 41, whereby the preheating device 21 is configured to be able to adjust the path width of the material feed path 22, which is the distance between the pair of path forming members 23. At least one of the path forming members 23 can be moved in the path width direction, for example, manually by a user placing a spacer between the path forming member 23 and its mounting location inside the housing 25, or automatically by using a motor or other actuator.

[0219] By making the passage width of the material feed passage 22 adjustable, it is possible to set an appropriate passage width according to each of the various molding materials Mm having various dimensions and shapes. For example, as shown in Fig. 41, when the passage width is set to a width that allows one piece of molding material Mm to pass through, the molding materials Mm pass through the material feed passage 22 in a substantially lined-up position, and at this time, most of the molding material Mm is effectively heated by the heating section 24 on the outer side in the passage width direction of the passage forming member 23. This effectively prevents unmelted material from being mixed into the molten molding material injected from the tip of the cylinder 11, thereby preventing poor appearance and reduced strength of the molded product.

[0220] The passage width set by the movable passage forming member 23 is preferably equal to or greater than the length of one piece of molding material Mm and less than the length of two pieces of molding material Mm. In this case, since the overlapping of a plurality of molding materials Mm in the passage width direction in the material feed passage 22 is suppressed, many of the molding materials Mm can be heated more effectively. The length of one piece of molding material Mm is preferably set to the shortest dimension of the molding material Mm. For example, if the molding material Mm is substantially spherical, it is preferably set to its diameter, or if the molding material Mm is irregularly shaped, including an ellipse or oval in cross section, it is preferably set to the diameter of the shortest short side. Alternatively, if the molding material Mm is cylindrical, prismatic, or other columnar, the shorter of the diameter or the width and height may be set to the length of one piece of molding material Mm.

[0221] A supply container 26 (cylinder supply container 26, also simply called supply container 26) for supplying molding material Mm to a cylinder such as a hopper is provided on the lower surface of the housing 25 at the tip end side (lower end side in FIG. 41) of the material passing direction of the material feed passage 22. In the illustrated example, the supply container 26 has a truncated cone-shaped portion 26a, the inner and outer shapes of which are both truncated cones, and a cylindrical portion 26b formed at the end of the small diameter side of the truncated cone-shaped portion 26a. The supply container 26 receives the molding material Mm that has passed through the material feed passage 22 in the truncated cone-shaped portion 26a, and then supplies it to the inside of the cylinder 11 through the cylindrical portion 26b at the end of the truncated cone-shaped portion 26a. An opening 26c having a width approximately the same as that of the material feed passage 22 is formed at the end of the truncated cone-shaped portion 26a, and the molding material Mm that has passed through the material feed passage 22 enters the supply container 26 from the opening 26c.

[0222] At the rear end side of the material feed passage 22 in the material passing direction (the upper end side in FIG. 41), a supply container 27 for supplying molding material to a passage such as a hopper that stores a plurality of molding materials Mm and supplies the molding material Mm in an appropriate amount to the material feed passage 22 (supply container 27 for supplying the passage, also simply referred to as supply container 27) is placed on the upper surface of the housing 25. The supply container 27 has a tube portion 27a having a cylindrical shape or the like, and a tapered portion 27b provided on the material feed passage 22 side of the tube portion 27a and having a gradually decreasing inner and outer diameter.

[0223] In the illustrated example, the molding material Mm is supplied to the preheating device 21 from a supply container 27 for supplying the passage. The molding material Mm supplied to the preheating device 21 passes through the material feed passage 22 while being preheated, and is supplied to the inside of the cylinder 11 after passing through the supply container 26 for supplying the cylinder. That is, here, the molding material Mm preheated by the preheating device 21 is supplied to the inside of the cylinder 11. However, the shape of the supply container 26 and / or the supply container 27 is not limited to this, and can be appropriately changed, and the supply container 26 and / or the supply container 27 may be omitted. If the supply container 26 for supplying the cylinder is omitted, the housing of the preheating device is placed on the cylinder, and the tip side of the material feed passage in the material passing direction is directly connected to the supply port of the cylinder. In this case, the molding material Mm preheated by the preheating device is supplied to the inside of the cylinder immediately after the preheating.

[0224] Here, the heating section 24 can be disposed on only one side of the material feed passage 22, outside one of the passage forming members 23 in the passage width direction, but in this embodiment, it is disposed on both sides of the material feed passage 22, outside each of the passage forming members 23 in the passage width direction. In this way, the molding material Mm can be heated quickly by the heating sections 24 on both sides, so that the molding material Mm can be effectively heated even if the passing speed of the molding material Mm through the material feed passage 22 is made relatively fast. Note that the conditions of the heating section 24, etc. are set so that the molding material Mm reaches a desired temperature at the tip end side of the material feed passage 22 in the material passing direction.

[0225] The heating unit 24 may be of any heating type as long as it can heat the molding material Mm through the passage forming member 23. For example, a hot air heating type heater that supplies a heating gas such as high-temperature air, an electric heater such as a high-frequency dielectric heater, an infrared heating type heater such as a halogen lamp or a ceramic heater, a laser heating type heater, etc. can be used. When the heating unit 24 is an infrared heating type heater or a laser heating type heater, the passage forming member 23 can be made of a translucent or transparent material such as glass through which light or a laser can pass. The arrangement of the heating unit 24 is not limited to the example in FIG. 41, and the heating unit 24 may be arranged outside the housing 25 and hot air may be flowed through the material feed passage 22.

[0226] The illustrated preheating device 21 has a heating section 24 including a hot air heater, for example. Specifically, the hot air heater can generate hot air by heating compressed air sent from a compressor with a sheathed heater or the like. The temperature of the hot air can be adjusted by changing the output of the sheathed heater.

[0227] In this case, the passage forming member 23 may have a plurality of ventilation holes penetrating the passage forming member 23 in the passage width direction in order to pass the heated gas sent from the hot air heater through the material feed passage 22. As a result, the heated gas from the heating unit 24 flows into the material feed passage 22 through the ventilation holes of the passage forming member 23, so that the molding material Mm in the material feed passage 22 can be heated by the heated gas.

[0228] Specifically, the passage forming member 23 may be a plate-like member in which a plurality of ventilation holes 23b are formed in a metal plate material 23a by press working, etc., as shown in Fig. 45(a), such as a so-called punched metal. In this case, by adjusting the processing mode, etc., a plurality of regularly arranged ventilation holes 23b can be formed in the plate material 23a.

[0229] Alternatively, as shown in FIG. 45(b), the passage forming member 23 may be a mesh member in which, for example, wires 23c are arranged in a lattice pattern, and a plurality of vent holes 23b are provided between the wires, each having a square or other polygonal shape when viewed from the front. If such a mesh member is thin and does not have the strength required to form the material feed passage 22 with the passage forming member 23, the mesh member and a reinforcing member may be overlapped to form the passage forming member 23. The reinforcing member may have various shapes, such as a honeycomb shape or a lattice shape, as long as it can pass the heated gas. For example, the mesh of the reinforcing member may be coarser than that of the mesh member. In the illustrated mesh member, a plurality of vent holes 23b are arranged in a regular line in the vertical direction (up and down direction in FIG. 45(b)) and horizontal direction (left and right direction in FIG. 45(b)) when viewed from the front.

[0230] For example, when the material feed passage 22 is defined by a mesh-like passage forming member 23, as shown in Fig. 46, a plurality of molding materials Mm spreads out in the lateral direction of the passage forming member 23 and moves in the material passing direction, which is the vertical direction of the passage forming member 23, as shown by the arrows in the figure. Note that between the pair of passage forming members 23, on each side of the material feed passage 22 in the lateral direction of the passage forming member 23, passage dividing members 22a, such as square rods, are arranged to divide the area of ​​the material feed passage 22 in the lateral direction of the passage forming member 23.

[0231] When the air holes 23b are evenly distributed and regularly arranged in a front view like the above-mentioned mesh-like or plate-like passage forming member 23, the heated gas from the heating section 24, which is a hot air heater, can be fed evenly to the material feed passage 22 in the vertical and horizontal directions of the passage forming member 23. This allows the heated gas to be blown onto many of the multiple molding materials Mm passing through the material feed passage 22, and the molding materials Mm can be heated even more effectively.

[0232] In the embodiment shown in FIG. 41, as the plasticization by the screw 12 or the like inside the cylinder 11 progresses, the molding material Mm is supplied from the supply container 26 for supplying the cylinder to the inside of the cylinder 11. Accordingly, the molding material Mm in the supply container 27 for supplying the passage passes through the material feed passage 22, is heated by the heating unit 24, and then is input into the supply container 26 for supplying the cylinder. In this case, the speed of the molding material Mm passing through the material feed passage 22 may depend on the speed of plasticization of the molding material Mm inside the cylinder 11, but the passing speed of the molding material Mm can also be adjusted by changing the passage width as described above. In addition, in order to adjust the speed at which the molding material Mm passes through the material feed passage 22 and the degree of heating of the molding material Mm influenced by it, a screw-shaped feeder or other supply adjustment device for adjusting the supply of the molding material Mm from the material feed passage 22 to the supply container 26 may be provided between the material feed passage 22 and the supply container 26, although not shown in the figure. Although not shown, there may be a mechanism for changing the position of the material feed passage 22 while keeping the passage width constant. By changing the position of the material feed passage 22, the amount of molding material Mm passing through per unit time can be adjusted.

[0233] Here, as described above, the preheating device 21 has a cooling section (not shown) that cools the molding material Mm passing through the material feed passage 22. In detail, the cooling section can be disposed outside the housing 25 that houses the material feed passage 22 and the like, as shown in Fig. 41, and by using piping or the like extending from the cooling section to the inside of the housing 25, the cooling medium generated in the cooling section can be caused to flow into the inside of the housing 25 to cool the molding material Mm passing through the material feed passage 22. The cooling medium generated by the cooling section may be not only cold air but also air at a temperature lower than the molding material Mm, for example, air at room temperature. The cooling section may be provided in the preheating device 21, but can be realized by making the heating section 24 structured to send room temperature gas such as cold air or cooling gas Gc.

[0234] Moreover, the preheating device 21 may further include a control unit that controls the heating unit 24 and / or the cooling unit, as shown in the block diagram of Fig. 42. More specifically, the control unit may control the heating unit 24 and / or the cooling unit based on signals obtained by the operation state detection mechanism, the retention detection mechanism, and / or the temperature information detection mechanism, as shown in Fig. 42.

[0235] The operation state detection mechanism of the preheating device 21 in the first embodiment detects the operation state of the injection device 1 when the operation of the injection molding machine stops for some reason, for example. The detection can be performed by providing a transmitter that transmits the operation state of the injection device 1, more specifically, a transmitter that transmits the operation state of the metering motor 31 and the injection motor 41 of the injection device 1. In addition, the retention detection mechanism detects information regarding retention of the molding material Mm when, for example, for some reason, the molding material Mm is retained in the material feed passage 22. The detection can be performed by using a sensor that detects retention of the molding material Mm in the material feed passage 22. However, in the preheating device 21 of the first embodiment, it is preferable to provide a mechanism for preventing the molding material Mm from stagnation in the material feed passage 22 in the first place, as will be described next.

[0236] That is, in the case of the first embodiment, in the case of a mesh-like or plate-like passage forming member 23 having a plurality of ventilation holes 23b, the molding material Mm may get caught in the ventilation holes 23b in the material feed passage 22 formed thereby, causing the molding material Mm to become clogged or accumulate in at least a portion of the lateral direction of the passage forming member 23. As described above, the accumulation of the molding material Mm in the material feed passage 22 may cause the molding material Mm to be excessively heated, and ultimately melt. Therefore, it is preferable to provide the preheating device 21 with a retention prevention mechanism for preventing retention of the molding material Mm in the material feed passage 22.

[0237] 47 to 50, the retention prevention mechanism can be a drive unit that displaces at least one of a pair of passage forming members 23 continuously during operation of the injection molding machine, or intermittently only when necessary, to change the relative position and / or orientation of one passage forming member 23 with respect to the other passage forming member 23. Note that illustration of the drive source is omitted here.

[0238] As shown in Fig. 47, square bar-shaped movable members 22b are provided on both lateral sides of one of the passage forming members 23, outside the passage width direction of the passage forming member 23. While the molding material Mm is passing through the material feed passage 22, the movable members 22b move one of the passage forming members 23 in the lateral direction of the passage forming member 23, as shown by the arrows in Figs. 47(b) and (c), thereby changing the relative position of one of the passage forming members 23 with respect to the other passage forming member 23. As a result, even if the molding material Mm gets caught in the ventilation hole 23b, the movement of one of the passage forming members 23 releases the catch, preventing the molding material Mm from stagnation. Furthermore, one of the passage forming members 23 may be moved not in the lateral direction of the passage forming member 23 but in the vertical direction (up and down direction) parallel to the material passing direction.

[0239] In the retention prevention mechanism shown in Fig. 48, a square bar-shaped movable member 22b is provided on each of both vertical ends of one of the passage forming members 23, outside the passage width direction of the passage forming member 23. As shown in Figs. 48(b) and (c), this retention prevention mechanism moves one of the passage forming members 23 in the passage width direction by the movable member 22b, and changes the relative position of one of the passage forming members 23 with respect to the other passage forming member 23, while the molding material Mm is passing through. At this time, the passage width of the material feed passage 22 increases and decreases slightly. The retention prevention mechanism in Fig. 48 can also be used as a mechanism for moving the passage forming member 23 to adjust the passage width as described above.

[0240] The retention prevention mechanism in Fig. 49 has a square bar-shaped movable member 22b provided on each of both vertical ends of one of the passage forming members 23 on the outer side of the passage width direction of the passage forming member 23, and a cylindrical or other fulcrum member 22c extending in the lateral direction of the passage forming member 23, which is sandwiched between the passage forming member 23 and the passage dividing member 22a at an intermediate position such as the center position in the material passing direction of the material feed passage 22. Here, the fulcrum member 22c is attached to the passage dividing member 22a. In this case, as shown in Figs. 49(b) and (c), when the movable members 22b are moved in mutually opposite directions in the passage width direction, one of the passage forming members 23 is pivotally displaced around the fulcrum member 22c and changes its orientation so as to be oblique to the other passage forming member 23. More specifically, when one end of one passage forming member 23 in the vertical direction approaches or moves away from the other passage forming member 23, the orientation of one passage forming member 23 changes so that the other end of one passage forming member 23 in the vertical direction approaches or moves away from the other passage forming member 23. Accordingly, the passage width of the material feed passage 22 may not be constant in the material passing direction. Even with such a retention prevention mechanism, retention of the molding material Mm can be effectively prevented.

[0241] The retention prevention mechanism in Fig. 50 has a configuration similar to that in Fig. 49, but the fulcrum member 22c is fixed and attached to one of the passage forming members 23, not to the passage partition member 22a. In Fig. 50, by driving the fulcrum member 22c to rotate without moving the movable member 22b, one of the passage forming members 23 rotates and displaces around the fulcrum member 22c together with the fulcrum member 22c, and the orientation relative to the other passage forming member 23 changes in a manner substantially similar to that in Fig. 49.

[0242] Alternatively, as shown in Fig. 51(a), the retention prevention mechanism may be configured with an impact applying part 28 that is arranged on the outside of at least one of the passage forming members 23 in the passage width direction and strikes the passage forming member 23 at a predetermined period or the like. The illustrated impact applying part 28 includes a plate-shaped member 28b that is provided parallel to the other passage forming member 23 on the outside of the other passage forming member 23 in the passage width direction and has one or more through holes 28a formed therein, and one or more pin-shaped members 28c that are disposed through the through holes 28a of the plate-shaped member 28b and displace toward or away from the other passage forming member 23. A similar impact applying part 28 may also be provided on the outside of one of the passage forming members 23 in the passage width direction.

[0243] In addition, the retention prevention mechanism may be configured as shown in Figure 51 (b) by a vibration imparting unit 29 such as one or more vibrators attached to at least one of the passage forming members 23, for example the outer surface in the passage width direction of the other passage forming member 23, and imparting vibrations to the passage forming member 23.

[0244] As shown in Fig. 52(a), the retention prevention mechanism may be a blower 30 that is disposed on at least one outer side of the passage width direction of the passage forming member 23 and blows gas at different flow rates through the vent holes 23b of the passage forming member 23 to the molding material Mm in the material feed passage 22. As shown in Fig. 52(b) or (c), the blower 30 changes the flow rate of the gas sent to the molding material Mm in the material feed passage 22 over time, thereby allowing the gas to be blown to the molding material Mm with varying strength. When sending gas from the blower 30 to the molding material Mm, a period of zero flow rate and a period of high flow rate may be repeated periodically as shown in Fig. 52(b), or a period of low flow rate and a period of high flow rate may be repeated periodically as shown in Fig. 52(c). Although the air blower 30 can be provided separately as a retention prevention mechanism, the heating unit 24, which is the above-mentioned hot air heater, can also be used as the air blower 30 and the heating unit 24 can also be used as a retention prevention mechanism. When the heating unit 24 is used both as a preheating and retention prevention mechanism, the gas from the air blower 30 corresponds to the heated gas from the heating unit 24. Moreover, the cooling unit described above can be simply structured for blowing air to serve as the air blowing unit 30, and the cooling unit can also be used as a retention prevention mechanism. When the cooling unit is used both as a cooling unit and a retention prevention mechanism, the gas from the air blowing unit 30 corresponds to the cooling gas from the cooling unit.

[0245] 47 to 52, the above-mentioned retention prevention mechanisms may be adopted alone or in combination in the preheating device 21. In other words, the preheating device 21 may include one or more of the retention prevention mechanisms shown in Figs. 47 to 52.

[0246] Although not shown in the drawings, as described above, the preheating device 21 is preferably provided with a retention detection mechanism that detects retention of the molding material Mm in the material feed passage 22. The retention detection mechanism may be, for example, a sensor that detects retention by temperature, an image captured by a camera, infrared rays, a laser, or the like.

[0247] Such a sensor of the retention detection mechanism is preferably provided at a portion on the leading end side of the material feed passage 22 in the material passing direction, that is, at a location near the material feed passage 22 before the supply container 26 for supplying the cylinder in the material passing direction. More specifically, as shown in Fig. 46, such a sensor 23d can be provided, for example, at a leading end side of the material feed passage 22 in the material passing direction, on the outer side of the passage width direction of the passage forming member 23, spaced apart from one another in the lateral direction of the passage forming member 23. This makes it possible to find a location where retention of the molding material Mm occurs in the lateral direction of the passage forming member 23 at an early stage.

[0248] If the sensor 23d of the retention detection mechanism is a temperature sensor, it is preferable to arrange the temperature sensor so that it can measure the temperature of the molding material Mm located at the tip end portion in the material passing direction of the material feed passage 22. The temperature of the molding material Mm referred to here may be the temperature of the molding material Mm itself, the temperature of the passage forming member 23, or the temperature in the space within the ventilation hole 23b of the passage forming member 23. In the case of a contact type temperature sensor, to measure the temperature of the molding material Mm itself or the temperature of the passage forming member 23, for example, the temperature sensor is passed through the ventilation hole 23b of the passage forming member 23 and arranged so that its tip is in contact with the molding material Mm, or so that the tip of the temperature sensor is in contact with the passage forming member 23. In addition, when the sensor 23d of the retention detection mechanism is a temperature sensor, it can be used as a temperature sensor that can be used in a temperature information detection mechanism that can be provided in the preheating device 21. In other words, when it is used as a temperature sensor, the preheating device 21 detects retention of the molding material Mm by the temperature sensor as the retention detection mechanism, and the control unit controls the heating unit 24 based on the detection of retention of the molding material Mm obtained by the retention detection mechanism, thereby stopping heating by the heating unit 24. When the temperature information detection mechanism detects information on the temperature of the molding material Mm in the material feed passage 22, specifically, for example, when the temperature of the molding material Mm measured by the temperature sensor meets a predetermined standard, the control unit can control the cooling unit to cool the molding material Mm based on the information on the temperature.

[0249] The aforementioned retention prevention mechanism can be operated continuously at all times while the injection molding machine is operating, or can be operated intermittently at specific times, such as when the retention detection mechanism detects retention of molding material Mm in the material feed passage 22.

[0250] In the preheating device 21, for example, a temperature sensor can be provided in the material feed passage 22 so that the temperature information detection mechanism can detect information related to the temperature (as described above, when the sensor 23d of the retention detection mechanism is used as a temperature sensor, it may also serve as a temperature sensor). More specifically, it is preferable to arrange the temperature sensor so that it can measure the temperature of the molding material Mm located at the tip end of the material feed passage 22 in the material passing direction. The temperature of the molding material Mm referred to here can be the temperature of the molding material Mm itself, the temperature of the passage forming member 23, or the temperature in the space within the ventilation hole 23b of the passage forming member 23. In the case of a contact type temperature sensor, to measure the temperature of the molding material Mm itself or the temperature of the passage forming member 23, for example, the temperature sensor is passed through the ventilation hole 23b of the passage forming member 23 and arranged so that its tip contacts the molding material Mm, or so that the tip of the temperature sensor contacts the passage forming member 23.

[0251] 53 shows a preheating device 121 of a first modified example of the first embodiment. This preheating device 121 has a supply container 127 for supplying passages and a supply container 126 for supplying cylinders, which are substantially similar to those of the previously described preheating device 21, but differs from the previously described preheating device 21 mainly in that a plurality of material feed passages 122 are provided in a housing 125 between them. By providing a plurality of material feed passages 122 in this way, the area per material feed passage 122 can be reduced, and the preheating device 121 can be made compact.

[0252] More specifically, the preheating device 121 has three material feed passages 122 arranged in parallel to each other, three pairs of passage forming members 123 dividing each of the material feed passages 122, and a heating section 124 for heating the molding material Mm in the material feed passages 122 from the outside in the passage width direction separated by the material feed passages 122 and the passage forming members 123, in order to feed the molding material Mm from a supply container 127 for supplying a passage to a supply container 126 for supplying a cylinder. Three openings 126c corresponding to the number of the material feed passages 122 are provided at the end of the truncated cone portion 126a of the supply container 126.

[0253] As in the illustrated embodiment, it is preferable to provide the heating sections 124 on both sides of each material feed passage 122 in the passage width direction from the viewpoint of realizing rapid and uniform preheating of the molding material Mm. This preheating device 121 is also configured such that at least one of a pair of passage forming members 123 forming each material feed passage 122 is movable, so that the passage width of each material feed passage 122 can be adjusted. Although not illustrated, it is also possible to provide two or four or more material feed passages.

[0254] Fig. 54 shows a preheating device 221 of a second modified example of the first embodiment. The preheating device 221 of Fig. 54 is provided with a pair of belt conveyors 223a including a plurality of rollers 223b including a drive roller and a driven roller, and a path forming member 223 which is an endless circular belt wound around the rollers 223b. A material feed path 222 through which the molding material Mm passes is defined between the belt conveyors 223a.

[0255] Each of the pair of belt conveyors 223a rotates and drives the path forming member 223 as a belt by the driving roller of the roller 223b, whereby the molding material Mm is sandwiched between the pair of belt conveyors 223a and conveyed through the material feed path 222 therebetween. The molding material Mm that has passed through the material feed path 222 is introduced into a supply container 226 for cylinder supply such as a hopper. This supply container 226 has a truncated cone-shaped portion 226a and a cylindrical portion 226b similar to the supply container 26 of the preheating device 21 described above, and further has a cylindrical opening 226c at the upper end of the truncated cone-shaped portion 226a for receiving the molding material Mm from the belt conveyor 223a. In this example, the molding material Mm is fed horizontally through the material feed passage 222 and then charged into the supply container 226. However, the pair of belt conveyors 223a may be arranged at an incline or perpendicular to the horizontal direction, so that the material passes through the material feed passage 222 in a direction at an incline or perpendicular to the horizontal direction.

[0256] The heating section 224 is disposed outside the belt conveyor 223a in the passage width direction. When the heating section 224 is the hot air heater described above, each belt as the passage forming member 223 can be configured, for example, of the mesh member described above so as to allow the passage of heated gas. This allows the heated gas to be sent to the molding material Mm passing through the material feed passage 222, and the molding material Mm can be effectively heated.

[0257] In addition, in order to adjust the passage width of the material feed passage 222, which is the distance between the pair of belt conveyors 223a, this preheating device 221 is configured to be able to move at least one of the pair of belt conveyors 223a together with the passage forming member 223 included therein, as shown by the white arrow in Figure 54.

[0258] The above-described preheating device 121 of the first modified example of the first embodiment and the preheating device 221 of the second modified example of the first embodiment can be controlled in the same manner as the preheating device 21 described above.

[0259] (Preheating device of the second embodiment) Next, the preheating device of the second embodiment will be described in more detail with reference to the drawings. A preheating device 60 of the second embodiment illustrated in Fig. 55 is attached to the rear end of the cylinder 11 opposite to the tip end 14 that injects the molding material in the rotation axis direction (left-right direction in Fig. 55) of the screw 12 of the injection device 1, similarly to the preheating device 21 of the first embodiment illustrated in Fig. 40. More specifically, the preheating device 60 is connected to a through-hole-like supply port 11a provided on a part of the circumference of the rear end of the cylinder 11 as illustrated in Fig. 56, and supplies molding material Mm, such as resin pellets having substantially spherical or cylindrical shapes or other shapes, to the supply port 11a.

[0260] Here, as shown in Figures 55 to 57, the preheating device 60 has a material passage 61 through which the molding material Mm passes, and a superheated steam inlet 62 that introduces superheated steam Ss into the material passage 61 in order to heat the molding material Mm in the material passage 61. In the material passage 61, the molding material Mm is heated by the superheated steam Ss introduced from the superheated steam inlet 62. This allows the molding material Mm to be preheated before being supplied into the cylinder 11.

[0261] The superheated steam introduced into the material passage 61 from the superheated steam inlet 62 can be generated by adding heat to the steam vaporized by boiling water in a superheated steam generator (not shown). Generally, heated air (hot air) heats the object to be heated by convection heat transfer, whereas superheated steam heats the object to be heated not only by convection heat transfer but also by radiation heat transfer and condensation heat transfer, and has a much larger thermal energy than heated air. Here, the molding material Mm is heated by the superheated steam introduced from the superheated steam inlet 62, so that the temperature of the molding material Mm rises to a predetermined temperature in a short time. As a result, in this embodiment, the molding material Mm is preheated instantly, and the molding cycle by the injection molding machine can be shortened. This is particularly advantageous when applied to high cycle molding.

[0262] For example, the superheated steam generator may have a structure in which a heating device such as a sheath heater is provided in a thermally insulated housing. In this case, the superheated steam generator can generate superheated steam by heating saturated steam sent from a boiler or the like. The superheated steam inlet 62 can be supplied with superheated steam generated by a superheated steam generator that can be installed in an injection molding machine including an injection unit, or it can be supplied with superheated steam that is separately generated in a specified facility at the installation site, such as a factory, where the injection unit is installed.

[0263] As shown in the illustrated example, the preheating device 60 may further have a passage partition wall 63 of a cylinder or other tubular shape provided around the material passage 61. Inside the passage partition wall 63, the material passage 61 is partitioned and provided. In this particular example, the cylindrical passage partition wall 63 is arranged laterally so that its central axis is substantially parallel to the rotation axis direction of the screw 12, which is, for example, a horizontal direction (the left-right direction in Figures 55 to 57). In the material passage 61 inside the passage partition wall 63, the molding material Mm moves in the above-mentioned rotation axis direction, so that the material passage direction, which is the direction in which the molding material Mm passes, becomes parallel to the rotation axis direction. However, the material passage 61 can be provided so that the material passage direction in the material passage 61 is a vertical direction perpendicular to the rotation axis direction of the screw 12 as in the embodiment described later, and the material passage 61 can also be provided obliquely so that the direction is inclined with respect to the rotation axis direction of the screw 12, although not shown in the drawings.

[0264] As shown in Figure 57, a hole-shaped passage inlet 61a is provided at the rear end side (right side in Figures 55 to 57) of the material passage 61 in the material passage direction by hollowing out a part in the circumferential direction of the passage partition wall 63. A substantially truncated cone-shaped hopper 61b can be attached to this passage inlet 61a. At the tip side of the material passage 61 in the material passage direction (left side in Figures 55 to 57), a passage outlet 61c is provided which protrudes toward the outer periphery of a part of the circumferential direction of the passage partition wall portion 63 and tapers toward the tip side, which is the lower side in the direction perpendicular to the material passage direction.

[0265] Moreover, the preheating device 60 may further include a conveying mechanism that sends the molding material Mm in the material passage 61 in the material passage 61. In this second embodiment, as an example of the conveying mechanism, a preheating screw 64 is provided in the material passage 61. In addition to the preheating screw 64, the conveying mechanism may be a belt conveyor or the like (not shown).

[0266] The illustrated preheating screw 64 includes a rotating shaft 65 that is driven to rotate about an axis along the material passage direction in the material passage 61, and a flight 66 that is provided upright on the outer circumferential surface of the rotating shaft 65 and extends in a predetermined shape such as a spiral around the axis, but the shape of the preheating screw 64 is not limited to this. When the preheating screw 64 is driven to rotate by a driving source 67 such as a motor, the molding material Mm is transported in the material passage 61 on the outer circumferential side of the rotating shaft 65 in the material passage direction by the flight 66 provided on the outer circumferential surface of the rotating shaft 65, as shown in FIG.

[0267] The preheating screw 64 of the second embodiment is a hollow rotating shaft 65. Specifically, as can be seen from Fig. 57, the rotating shaft 65 has an internal space 68 therein, a cylindrical peripheral wall portion 69 that defines the internal space 68, and a plurality of communication holes 70 formed in the peripheral wall portion 69 by penetrating the peripheral wall portion 69. Here, the superheated steam inlet 62 is provided in the preheating screw 64, more specifically, in the tip surface in the rotational axis direction of the rotating shaft 65 of the preheating screw 64. For example, the tip portion in the rotational axis direction of the rotating shaft 65 of the preheating screw 64 can be positioned so as to be exposed to the outside of the passage partition wall portion 63 through an opening 63a provided in the end surface of the passage partition wall portion 63, and the superheated steam inlet 62 can be provided in the tip portion.

[0268] In the material passage 61 in which such a preheating screw 64 is disposed, the superheated steam Ss introduced into the material passage 61 from the superheated steam inlet 62 first flows into the internal space 68 of the rotating shaft 65 of the preheating screw 64 within the material passage 61. The superheated steam Ss that has flowed into the internal space 68 is then sent from the internal space 68 through a plurality of communication holes 70 provided in a peripheral wall portion 69 to the outer periphery of the rotating shaft 65. On the outer periphery of the rotating shaft 65, the molding material Mm being transported in the material passage direction by the flight 66 is heated by the superheated steam Ss that has passed through the communication holes 70.

[0269] In addition, the height of the outer periphery of the flight 66 from the outer periphery of the rotating shaft 65 (groove depth of the preheating screw 64) is preferably equal to or greater than the length of one piece of molding material Mm and less than the length of two pieces of molding material Mm. In this case, since the multiple molding materials Mm are prevented from overlapping in the radial direction of the preheating screw 64 on the outer periphery of the rotating shaft 65, each molding material Mm passing through the material passage 61 can be heated more effectively by, for example, superheated steam sent from the communication hole 70 of the rotating shaft 65 to the outer periphery. This effectively prevents unmelted material from being mixed with the molten molding material injected from the tip 14 of the cylinder 11, thereby preventing poor appearance and strength reduction of the molded product. In addition, it is preferable that the gap between the outer peripheral edge of the flight 66 and the inner peripheral surface of the passage partition wall 63 in the radial direction of the preheating screw 64 is narrower than the length of one piece of molding material Mm. This makes it possible to prevent the molding material Mm from climbing over the flight 66 in the rotation axis direction. Note that a minute gap is provided between the outer peripheral edge of the flight 66 and the inner peripheral surface of the passage partition wall 63 so that they do not come into contact with each other. Furthermore, it is preferable that the distance from the outer peripheral surface of the rotating shaft 65 of the preheating screw 64 to the inner peripheral surface of the passage partition wall portion 63 is at least the length of one piece of molding material Mm and less than the length of two pieces of molding material Mm. The length of one piece of molding material Mm is preferably the shortest dimension of the molding material Mm. For example, if the molding material Mm is substantially spherical, the length is preferably the diameter of the molding material Mm, or if the molding material Mm is an irregular sphere having an ellipse or oval cross section, the length is preferably the diameter of the shortest short side of the molding material Mm. Alternatively, if the molding material Mm is cylindrical, prismatic, or other prismatic, the length of one piece of molding material Mm may be the shorter of the diameter or the width and height of the molding material Mm.

[0270] Instead of the above-mentioned superheated steam inlet 62, passage partition wall 63, and preheating screw 64, a superheated steam inlet 162, passage partition wall 163, and preheating screw 164 of a first modified example of the second embodiment shown in Fig. 58 may be used. In Fig. 58, the passage partition wall 163 is provided with a plurality of superheated steam inlets 162 in the circumferential direction and the rotation axis direction, each of which is a through hole penetrating the passage partition wall 163. The preheating screw 164 may have a rotating shaft 165 which is either hollow or solid, but does not have the communication hole 70 as described above. In addition, no opening is provided on the end face of the passage partition wall 163, and the tip end of the rotating shaft 165 in the rotation axis direction terminates inside the passage partition wall 163. In a first modified example of the second embodiment shown in Fig. 58, superheated steam is introduced into the material passage 61 from a superheated steam inlet 162 provided in a passage partition wall 163. This heats the molding material Mm transported on the outer circumferential side of the rotating shaft 165. The first modified example of the second embodiment shown in Fig. 58 has substantially the same configuration as those shown in Figs. 55 to 57, except for the structures of the superheated steam inlet 162, the passage partition wall 163, and the preheating screw 164.

[0271] Alternatively, as shown in Fig. 59, the configuration shown in Figs. 55 to 57 may be further provided with a plurality of through-hole-shaped superheated steam inlets 262 in the passage partition wall 263. In the second modified example of the second embodiment shown in Fig. 59, the molding material Mm conveyed on the outer circumferential side of the rotating shaft 65 of the preheating screw 64 is heated by superheated steam sent from both the inner and outer sides in the radial direction (the vertical direction in Fig. 59) of the preheating screw 64 by the superheated steam inlet 262 in the passage partition wall 263 and the superheated steam inlet 62 in the preheating screw 64. The second modified example of the second embodiment shown in Fig. 59 has substantially the same configuration as that shown in Figs. 55 to 57, except that the superheated steam inlet 262 is provided in the passage partition wall 263.

[0272] As described above, it is preferable that the communication holes 70 in the peripheral wall 69 of the preheating screw 64 and the superheated steam inlets 162, 262 in the passage partition walls 163, 263 are provided in large numbers and uniformly distributed in the circumferential direction and the rotation axis direction of the peripheral wall 69 or the passage partition walls 163, 263. In order to realize such a preheating screw 64 and the passage partition walls 163, 263, the peripheral wall 69 and / or the passage partition walls 163, 263 can be made of, for example, a cylindrical mesh member having a plurality of holes having a square or other polygonal shape when viewed from the front, or a cylindrical plate member such as a so-called punching metal in which a plurality of holes are formed by pressing a metal plate. If the mesh member is not strong enough, the peripheral wall 69 and / or the passage partition walls 163, 263 may be made of a mesh member superimposed on a reinforcing member having a honeycomb or lattice shape.

[0273] For example, when the plasticizing capacity of the cylinder 11 of the injection device 1 is high and it is required to supply the molding material Mm to the cylinder 11 at a higher speed, the outer diameter of the preheating screw 64, 164 can be increased. Alternatively, as shown in the cross-sectional view of the material passage from above in FIG. 60, a material passage 361 for sending the molding material Mm to one passage outlet 361c is arranged around the passage outlet 361c, for example, together with a passage partition wall 363 surrounding it and a preheating screw 364 inside it, in the third modified example of the second embodiment shown in FIG. 60, four straight material passages 361 are arranged around the passage outlet 361c at an angle of 90° from each other, but the number and arrangement of the material passages 361 can be changed as appropriate. When a plurality of material passages 361 are provided, a superheated steam inlet is provided so that superheated steam is introduced into each material passage 361. In this example, for example, a plurality of superheated steam inlets can be provided in each passage partition wall 363. Also, a vent for superheated steam may be provided.

[0274] As described above, the superheated steam that heats the molding material Mm in the material passage 61 can rapidly increase the temperature of the molding material Mm. On the other hand, when the molding material Mm heated by the superheated steam becomes lower in temperature than, for example, 100° C., condensation may occur.

[0275] In order to remove moisture due to such condensation, etc., and to dry or further heat the molding material Mm that has passed through the material passage 61 and been heated by superheated steam, the preheating device 60 of the second embodiment further includes a material feed passage 22 through which the molding material Mm passes after being heated by superheated steam and passing through the material passage 61, and a heating section 24 that heats the molding material Mm passing through the material feed passage 22, as shown in Fig. 56. In this second embodiment, the molding material Mm passes through the above-mentioned material passage 61 in the direction of the rotation axis, and then falls into the material feed passage 22 from the passage outlet 61c of the material passage 61 due to its own weight, and passes through the material feed passage 22. Here, the material passing direction in the material passage 61 is perpendicular to the material passing direction (the up and down direction in Fig. 56) in which the molding material Mm passes through the material feed passage 22, and the molding material Mm passes through the material feed passage 22 in the vertical direction.

[0276] The material feed passage 22 has a pair of passage forming members 23 arranged opposite each other to define the material feed passage 22 between them. The heating unit 24 is arranged outside the material feed passage 22 in the passage width direction separated from the material feed passage 22 by the passage forming member 23. The passage forming member 23 and the heating unit 24 have a function of drying the molding material Mm that has been heated by superheated steam and passed through the material passage 61, and also have a function of further heating the molding material Mm. The passage width direction here means the alignment direction of the passage forming members 23 arranged in parallel with each other, and means a direction perpendicular to the material passing direction in the material feed passage 22 (the left-right direction in FIG. 56). In the illustrated embodiment, the material feed passage 22, the passage forming member 23, and the heating unit 24 are accommodated and arranged inside a box-shaped housing 25 made of a heat insulating material or the like.

[0277] At least one of the pair of path forming members 23 that define the material feed path 22 can be movable, so that the material feed path 22 is configured to be adjustable in its path width, which is the distance between the pair of path forming members 23. At least one of the path forming members 23 may be moved in the path width direction, for example, manually by a user placing a spacer between the path forming member 23 and its mounting location inside the housing 25, or automatically by using a motor or other actuator. If the path width of the material feed path 22 is adjustable, an appropriate path width can be set according to each of the various molding materials Mm having various dimensions and shapes. For example, as shown in FIG. 56, when the path width is set to a value that allows one piece of molding material Mm to pass through, the molding material Mm passes through the material feed path 22 in a substantially aligned position, and at this time, most of the molding material Mm is effectively heated by the heating section 24 on the outer side of the path width direction of the path forming member 23.

[0278] It is preferable that the passage width of the material feed passage 22 is equal to or greater than the length of one piece of molding material Mm and less than the length of two pieces of molding material Mm. In this case, since the material feed passage 22 prevents a plurality of pieces of molding material Mm from overlapping in the passage width direction, it is possible to heat many of the molding materials Mm more effectively.

[0279] A supply container 26 such as a hopper is provided on the lower surface of the housing 25 at the tip side (lower end side in FIG. 56) of the material feed passage 22 in the material passing direction. In the illustrated example, the supply container 26 has, for example, a truncated cone-shaped portion 26a whose inner and outer shapes are both truncated cones, and a cylindrical portion 26b formed at the end of the small diameter side of the truncated cone-shaped portion 26a. The supply container 26 preferably includes a thermal insulator, for example, by making the peripheral wall of the supply container 26 out of a thermal insulator or by covering the surface of the peripheral wall with a thermal insulator. The supply container 26 receives the molding material Mm that has passed through the material feed passage 22 in the truncated cone-shaped portion 26a, and then supplies the molding material Mm through the cylindrical portion 26b at the end of the truncated cone-shaped portion 26a to the inside of the cylinder 11. An opening 26c having a width approximately the same as that of the material feed passage 22 is formed at the end of the truncated cone-shaped portion 26a, and the molding material Mm that has passed through the material feed passage 22 enters the supply container 26 from the opening 26c.

[0280] In the illustrated example, the molding material Mm passes through the material feed passage 22 and the supply container 26, and is then supplied to the inside of the cylinder 11. In other words, the molding material Mm preheated by the preheating device 60 is supplied to the inside of the cylinder 11. However, the shape of the supply container 26 is not limited to this, and can be changed as appropriate, and the supply container 26 may be omitted. If the supply container 26 is omitted, a housing is placed on the cylinder, and the tip side of the material feed passage in the material passing direction is directly connected to the supply port of the cylinder. In this case, the molding material is supplied to the inside of the cylinder immediately after passing through the material feed passage.

[0281] Here, the heating section 24 can be disposed on only one side of the material feed passage 22, outside one of the passage forming members 23 in the passage width direction, but in this second embodiment, it is disposed on both sides of the material feed passage 22, outside each of the passage forming members 23 in the passage width direction. In this way, the molding material Mm can be heated quickly by the heating sections 24 on both sides, so that the molding material Mm can be effectively heated even if the passing speed of the molding material Mm through the material feed passage 22 is made relatively fast. Note that the conditions of the heating section 24, etc. are set so that the molding material Mm reaches a desired temperature at the tip side of the material feed passage 22 in the material passing direction.

[0282] The heating unit 24 may be of any heating type as long as it can heat the molding material Mm through the passage forming member 23. For example, a hot air heater that supplies a heated gas such as high-temperature air, an electric heater such as a high-frequency dielectric heater, an infrared heater such as a halogen lamp or a ceramic heater, or a laser heater may be used. When the heating unit 24 is an infrared heater or a laser heater, the passage forming member 23 may be made of a translucent or transparent material such as glass through which light or a laser can pass. The arrangement of the heating unit 24 is not limited to the example shown in FIG. 56, and the heating unit 24 may be arranged outside the housing 25 and hot air may be caused to flow through the material feed passage 22.

[0283] The illustrated preheating device 60 has, as an example, a heating section 24 including a hot air heater. Specifically, the hot air heater can be one that obtains hot air by, for example, heating compressed air sent from a compressor with a sheathed heater or the like. The temperature of the hot air can be adjusted by changing the output of the sheathed heater. The hot air heater is preferable in that it can more effectively dry the molding material Mm.

[0284] In this case, the passage forming member 23 may have a plurality of ventilation holes penetrating the passage forming member 23 in the passage width direction in order to pass the heated gas sent from the hot air heater through the material feed passage 22. As a result, the heated gas from the heating unit 24 flows into the material feed passage 22 through the ventilation holes of the passage forming member 23, so that the molding material Mm in the material feed passage 22 can be heated by the heated gas.

[0285] Specifically, the passage forming member 23 may be a plate-like member in which a plurality of ventilation holes 23b are formed in a metal plate material 23a by press working, etc., as shown in Fig. 45(a), such as a so-called punched metal. In this case, by adjusting the processing mode, etc., a plurality of regularly arranged ventilation holes 23b can be formed in the plate material 23a.

[0286] Alternatively, as shown in FIG. 45(b), the passage forming member 23 may be a mesh member in which, for example, wires 23c are arranged in a lattice pattern, and a plurality of vent holes 23b are provided between the wires, each having a square or other polygonal shape when viewed from the front. If such a mesh member is thin and does not have the strength required to form the material feed passage 22 with the passage forming member 23, the mesh member and a reinforcing member may be overlapped to form the passage forming member 23. The reinforcing member may have various shapes, such as a honeycomb shape or a lattice shape, as long as it can pass heated gas. For example, the mesh of the reinforcing member may be coarser than that of the mesh member. In the illustrated mesh member, a plurality of vent holes 23b are regularly arranged in a vertical direction (up and down direction in FIG. 45(b)) and a horizontal direction (left and right direction in FIG. 45(b)) perpendicular to the vertical direction when viewed from the front.

[0287] For example, when the material feed passage 22 is defined by a mesh-like passage forming member 23, as shown in Fig. 46, a plurality of molding materials Mm spreads out in the lateral direction of the passage forming member 23 and moves in the material passing direction, which is the vertical direction of the passage forming member 23, as shown by the arrows in the figure. Note that between the pair of passage forming members 23, on each side of the material feed passage 22 in the lateral direction of the passage forming member 23, passage dividing members 22a, such as square rods, are arranged to divide the area of ​​the material feed passage 22 in the lateral direction of the passage forming member 23.

[0288] When the air holes 23b are evenly distributed and regularly arranged in a front view like the above-mentioned mesh-like or plate-like passage forming member 23, the heated gas from the heating section 24, which is a hot air heater, can be fed evenly to the material feed passage 22 in the vertical and horizontal directions of the passage forming member 23. This allows the heated gas to be blown onto many of the multiple molding materials Mm passing through the material feed passage 22, and the molding materials Mm can be heated even more effectively.

[0289] In the second embodiment, as the plasticization of the molding material by the screw 12 inside the cylinder 11 progresses, the molding material Mm is supplied from the supply container 26 to the inside of the cylinder 11. Accordingly, the molding material Mm that has passed through the material passage 61 passes through the material feed passage 22, is heated by the heating unit 24, and then is fed into the supply container 26. In this case, the speed of the molding material Mm passing through the material feed passage 22 may depend on the speed of plasticization of the molding material Mm inside the cylinder 11, but the passing speed of the molding material Mm can also be adjusted by changing the passage width as described above. In addition, in order to adjust the speed at which the molding material Mm passes through the material feed passage 22 and the degree of heating of the molding material Mm that is influenced by the speed, a screw-shaped feeder or other supply adjuster that adjusts the supply of the molding material Mm from the material feed passage 22 to the supply container 26 may be provided between the material feed passage 22 and the supply container 26, although not shown in the figure. Although not shown, there may be a mechanism for changing the position of the material feed passage 22 while keeping the passage width constant. By changing the position of the material feed passage 22, the amount of molding material passing through per unit time can be adjusted.

[0290] Incidentally, as described above, the preheating device 60 has a cooling section (not shown) that cools the molding material Mm passing through the material feed passage 22. In detail, the cooling section can be disposed outside the housing 25 that houses the material feed passage 22 and the like, as shown in Fig. 56, and by using piping or the like extending from the cooling section to the inside of the housing 25, the cooling medium generated in the cooling section can be caused to flow into the inside of the housing 25 to cool the molding material Mm passing through the material feed passage 22. The cooling medium generated by the cooling section can be not only cold air but also air at a temperature lower than the molding material Mm, for example, air at room temperature. The cooling section may be provided in the preheating device 21, but can be realized by making the heating section 24 structured to send room temperature gas such as cold air or cooling gas Gc.

[0291] In the second embodiment, the preheating devices 60, 360, 460 can be controlled in the same manner as the preheating device 21 in the first embodiment described above. That is, the preheating devices 60, 360, 460 can further include a control unit that controls the heating unit 24 and / or the cooling unit. More specifically, the control unit can control the heating unit 24 and / or the cooling unit based on signals obtained by the operation state detection mechanism, the retention detection mechanism, and / or the temperature information detection mechanism.

[0292] The operation state detection mechanism of the second embodiment detects the operation state of the injection device 1 when the operation of the injection molding machine stops for some reason, for example. The detection can be performed by providing a transmitter that transmits the operation status of the injection device 1, more specifically, a transmitter that transmits the operation status of the metering motor 31 and the injection motor 41 of the injection device 1. Furthermore, the retention detection mechanism detects information regarding retention of the molding material Mm when, for example, for some reason, the molding material Mm is retained in the material feed passage 22. The detection can be performed by using a sensor that detects retention of the molding material Mm in the material feed passage 22. However, in the preheating device 60 of the second embodiment, as will be described next, it is preferable to provide the preheating device 60 with a mechanism for preventing retention of the molding material Mm in the material feed passage 22.

[0293] That is, in the case of the second embodiment, in a mesh-like or plate-like passage forming member 23 having a plurality of ventilation holes 23b, the molding material Mm may get caught in the ventilation holes 23b in the material feed passage 22 formed thereby, causing retention such as clogging of the molding material Mm in at least a portion of the lateral direction of the passage forming member 23. Retention of the molding material Mm in the material feed passage 22 may lead to excessive heating of the molding material Mm, and ultimately to melting of the molding material Mm. Therefore, it is preferable to provide the preheating device 60 with a retention prevention mechanism that prevents the molding material Mm from retaining in the material feed passage 22.

[0294] 47 to 50, the retention prevention mechanism can be a drive unit that displaces at least one of a pair of passage forming members 23 continuously during operation of the injection molding machine, or intermittently only when necessary, to change the relative position and / or orientation of one passage forming member 23 with respect to the other passage forming member 23. Note that illustration of the drive source is omitted here.

[0295] As shown in Fig. 47, square bar-shaped movable members 22b are provided on both lateral sides of one of the passage forming members 23, outside the passage width direction of the passage forming member 23. While the molding material Mm is passing through the material feed passage 22, the movable members 22b move one of the passage forming members 23 in the lateral direction of the passage forming member 23, as shown by the arrows in Figs. 47(b) and (c), thereby changing the relative position of one of the passage forming members 23 with respect to the other passage forming member 23. As a result, even if the molding material Mm gets caught in the ventilation hole 23b, the movement of one of the passage forming members 23 releases the catch, preventing the molding material Mm from stagnation. Furthermore, one of the passage forming members 23 may be moved not in the lateral direction of the passage forming member 23 but in the vertical direction (up and down direction) parallel to the material passing direction.

[0296] In the retention prevention mechanism shown in Fig. 48, a square bar-shaped movable member 22b is provided on each of both vertical ends of one of the passage forming members 23, outside the passage width direction of the passage forming member 23. As shown in Figs. 48(b) and (c), this retention prevention mechanism moves one of the passage forming members 23 in the passage width direction by the movable member 22b, and changes the relative position of one of the passage forming members 23 with respect to the other passage forming member 23, while the molding material Mm is passing through. At this time, the passage width of the material feed passage 22 increases and decreases slightly. The retention prevention mechanism in Fig. 48 can also be used as a mechanism for moving the passage forming member 23 to adjust the passage width as described above.

[0297] The retention prevention mechanism in Fig. 49 has a square bar-shaped movable member 22b provided on each of both vertical ends of one of the passage forming members 23 on the outer side of the passage width direction of the passage forming member 23, and a cylindrical or other fulcrum member 22c extending in the lateral direction of the passage forming member 23, which is sandwiched between the passage forming member 23 and the passage dividing member 22a at an intermediate position such as the center position in the material passing direction of the material feed passage 22. Here, the fulcrum member 22c is attached to the passage dividing member 22a. In this case, as shown in Figs. 49(b) and (c), when the movable members 22b are moved in mutually opposite directions in the passage width direction, one of the passage forming members 23 is pivotally displaced around the fulcrum member 22c and changes its orientation so as to be oblique to the other passage forming member 23. More specifically, when one end of one passage forming member 23 in the vertical direction approaches or moves away from the other passage forming member 23, the orientation of one passage forming member 23 changes so that the other end of one passage forming member 23 in the vertical direction approaches or moves away from the other passage forming member 23. Accordingly, the passage width of the material feed passage 22 may not be constant in the material passing direction. Even with such a retention prevention mechanism, retention of the molding material Mm can be effectively prevented.

[0298] The retention prevention mechanism in Fig. 50 has a configuration similar to that in Fig. 49, but the fulcrum member 22c is fixed and attached to one of the passage forming members 23, not to the passage partition member 22a. In Fig. 51, by driving the fulcrum member 22c to rotate without moving the movable member 22b, one of the passage forming members 23 rotates and displaces around the fulcrum member 22c together with the fulcrum member 22c, and the orientation relative to the other passage forming member 23 changes in a manner substantially similar to that in Fig. 49.

[0299] Alternatively, as shown in Fig. 51(a), the retention prevention mechanism may be configured with an impact applying part 28 that is arranged on the outside of at least one of the passage forming members 23 in the passage width direction and strikes the passage forming member 23 at a predetermined period or the like. The illustrated impact applying part 28 includes a plate-shaped member 28b that is provided parallel to the other passage forming member 23 on the outside of the other passage forming member 23 in the passage width direction and has one or more through holes 28a formed therein, and one or more pin-shaped members 28c that are disposed through the through holes 28a of the plate-shaped member 28b and displace toward or away from the other passage forming member 23. A similar impact applying part 28 may also be provided on the outside of one of the passage forming members 23 in the passage width direction.

[0300] In addition, the retention prevention mechanism may be configured as shown in Figure 51 (b) by a vibration imparting unit 29 such as one or more vibrators attached to at least one of the passage forming members 23, for example the outer surface in the passage width direction of the other passage forming member 23, and imparting vibrations to the passage forming member 23.

[0301] As shown in Fig. 52(a), the retention prevention mechanism may be a blower 30 that is disposed on at least one outer side of the passage width direction of the passage forming member 23 and blows gas at different flow rates through the vent holes 23b of the passage forming member 23 to the molding material Mm in the material feed passage 22. As shown in Fig. 52(b) or (c), the blower 30 changes the flow rate of the gas sent to the molding material Mm in the material feed passage 22 over time, thereby allowing the gas to be blown to the molding material Mm with varying strength. When sending gas from the blower 30 to the molding material Mm, a period of zero flow rate and a period of high flow rate may be repeated periodically as shown in Fig. 52(b), or a period of low flow rate and a period of high flow rate may be repeated periodically as shown in Fig. 52(c). Although the air blower 30 can be provided separately as a retention prevention mechanism, the heating unit 24, which is the above-mentioned hot air heater, can also be used as the air blower 30 and the heating unit 24 can also be used as a retention prevention mechanism. When the heating unit 24 is used both as a preheating and retention prevention mechanism, the gas from the air blower 30 corresponds to the heated gas from the heating unit 24. Moreover, the cooling unit described above can be simply structured for blowing air to serve as the air blowing unit 30, and the cooling unit can also be used as a retention prevention mechanism. When the cooling unit is used both as a cooling unit and a retention prevention mechanism, the gas from the air blowing unit 30 corresponds to the cooling gas from the cooling unit.

[0302] 47 to 52, the above-mentioned retention prevention mechanisms may be adopted alone or in combination in the preheating device 60. In other words, the preheating device 60 may include one or more of the retention prevention mechanisms shown in FIGS.

[0303] Moreover, the preheating device 60 is preferably provided with a retention detection mechanism that detects retention of the molding material Mm in the material feed passage 22. The retention detection mechanism may be, for example, a sensor that detects retention by temperature, an image taken by a camera, infrared rays, a laser, or the like.

[0304] Such a sensor of the retention detection mechanism is preferably provided at a portion on the leading end side of the material feed passage 22 in the material passing direction, that is, at a location near the material feed passage 22 before the supply container 26 in the material passing direction. More specifically, as shown in Fig. 46, such a sensor 23d can be provided, for example, at a plurality of sensors spaced apart from one another in the lateral direction of the passage forming member 23 on the leading end side of the material feed passage 22 in the material passing direction, on the outer side of the passage width direction of the passage forming member 23. This makes it possible to find early a location where retention of the molding material Mm occurs in the lateral direction of the passage forming member 23.

[0305] If the sensor 23d of the retention detection mechanism is a temperature sensor, it is preferable to arrange the temperature sensor so that it can measure the temperature of the molding material Mm located at the tip end portion in the material passing direction of the material feed passage 22. The temperature of the molding material Mm referred to here may be the temperature of the molding material Mm itself, the temperature of the passage forming member 23, or the temperature in the space within the ventilation hole 23b of the passage forming member 23. In the case of a contact type temperature sensor, to measure the temperature of the molding material Mm itself or the temperature of the passage forming member 23, for example, the temperature sensor is passed through the ventilation hole 23b of the passage forming member 23 and arranged so that its tip is in contact with the molding material Mm, or so that the tip of the temperature sensor is in contact with the passage forming member 23. In addition, when the sensor 23d of the retention detection mechanism is a temperature sensor, it can be used as a temperature sensor that can be used in a temperature information detection mechanism that the preheating device 60 can be equipped with. In other words, when it is used as a temperature sensor, the preheating device 60 detects retention of the molding material Mm by the temperature sensor as the retention detection mechanism, and the control unit controls the heating unit 24 based on the detection of retention of the molding material Mm obtained by the retention detection mechanism, thereby stopping heating by the heating unit 24. When the temperature information detection mechanism detects information on the temperature of the molding material Mm in the material feed passage 22, specifically, for example, when the temperature of the molding material Mm measured by the temperature sensor meets a predetermined standard, the control unit can control the cooling unit to cool the molding material Mm based on the information on the temperature.

[0306] The aforementioned retention prevention mechanism can be operated continuously at all times while the injection molding machine is operating, or can be operated intermittently at specific times, such as when the retention detection mechanism detects retention of molding material Mm in the material feed passage 22.

[0307] In the preheating device 60, for example, a temperature sensor can be provided in the material feed passage 22 so that the temperature information detection mechanism detects information related to the temperature (as described above, when the sensor 23d of the retention detection mechanism is used as a temperature sensor, it may also serve as a temperature sensor). More specifically, it is preferable to arrange the temperature sensor so that it can measure the temperature of the molding material Mm located at the tip end of the material feed passage 22 in the material passing direction. The temperature of the molding material Mm referred to here can be the temperature of the molding material Mm itself, the temperature of the passage forming member 23, or the temperature in the space within the ventilation hole 23b of the passage forming member 23. In the case of a contact type temperature sensor, to measure the temperature of the molding material Mm itself or the temperature of the passage forming member 23, for example, the temperature sensor is passed through the ventilation hole 23b of the passage forming member 23 so that its tip contacts the molding material Mm, or the temperature sensor is arranged so that its tip contacts the passage forming member 23.

[0308] Furthermore, in the second embodiment, it is preferable that the control unit controls the introduction of superheated steam in addition to the heating unit 24 and / or the cooling unit, and it is also preferable that the control unit controls the heating unit 24 and the introduction of superheated steam based on information regarding the stop of operation of the injection device 1 detected by the operation state detection mechanism and / or information regarding the accumulation of molding material Mm detected by the accumulation detection mechanism. When the control unit receives such information, the control unit controls to stop heating by the heating unit 24 and to stop the introduction of superheated steam, thereby making it possible to further prevent the molding material Mm from melting and fusing.

[0309] Although not shown in the drawings, a plurality of material feed passages may be provided. In this case, the area of ​​each material feed passage can be reduced, and the preheating device can be made compact. For example, when two or more material feed passages arranged in parallel with each other are provided, it is preferable to provide heaters on both sides of each material feed passage in the passage width direction from the viewpoint of realizing rapid and uniform preheating of the molding material Mm.

[0310] On the other hand, as in the fourth modified example of the second embodiment shown in FIG. 61, the above-mentioned material feed passage may be omitted, and the passage outlet 61c of the material passage 61 may be directly connected to the opening 26c of the supply container 26. The preheating device 260 in FIG. 61 has a substantially similar configuration to that in FIG. 56, except that the housing 25 and its internal structure (i.e., the material feed passage 22, the passage forming member 23, and the heating unit 24) of the preheating device 60 in FIG. 56 are omitted. In the preheating device 260 shown in FIG. 61, the molding material Mm that has passed through the material passage 61 while being heated by the superheated steam Ss is supplied to the inside of the cylinder 11 through the supply container 26. In this case, a hot air heater (not shown) may be provided at the passage outlet 61c of the material passage 61, and the molding material Mm may be dried there. Although not shown, the supply container 26 may also be omitted, and the passage outlet of the material passage may be connected to the supply port of the cylinder. In this modification, for example, a temperature sensor can be provided in the material passage 61 so that the temperature information detection mechanism can detect information related to the temperature. More specifically, it is preferable to arrange the temperature sensor so that the temperature sensor can measure the temperature of the molding material Mm located at the tip end of the material passage 61 in the material passing direction. The temperature of the molding material Mm referred to here can be the temperature of the molding material Mm itself, the temperature of the preheating screw 64, or the temperature in the space within the communication hole 70 of the preheating screw 64. In the case of a contact type temperature sensor, in order to measure the temperature of the molding material Mm itself or the temperature of the preheating screw 64, for example, the temperature sensor is passed through the communication hole 70 of the preheating screw 64 and arranged so that its tip is in contact with the molding material Mm, or so that the tip of the temperature sensor is in contact with the preheating screw 64.

[0311] Fig. 62 shows a preheating device 460 according to a fifth modified example of the second embodiment. The preheating device 460 in Fig. 62 does not have a conveying mechanism such as a preheating screw, and the molding material Mm passes through a material passage 461 while dropping downward under its own weight. Here, the material passage direction of the material passage 461 is parallel to the vertical direction, similar to the material passage direction of the material feed passage 22, but the material passage 461 can also be inclined with respect to the vertical direction as long as the molding material Mm can pass through it. In the preheating device 460, for example, a plurality of superheated steam inlets 462 are provided in a passage partition wall portion 463 around the material passage 461. The superheated steam Ss is sent from the superheated steam inlets 462 into the material passage 461 to heat the molding material Mm.

[0312] Even in a preheating device 460 having such a material passage 461 and a superheated steam inlet 462, the housing 25 and its internal structure (i.e., the material feed passage 22, the passage forming member 23 and the heating section 24), and / or the supply container 26 may be omitted.

[0313] (Preheating device of the third embodiment) Next, the preheating device of the third embodiment will be described in more detail with reference to the drawings. A preheating device 81 of the third embodiment illustrated in Fig. 63 is attached to the rear end of the cylinder 11 opposite to the tip end 14 that injects the molding material Mm in the rotation axis direction (left-right direction in Fig. 63) of the screw 12 of the injection device 1, similarly to the preheating device 21 of the first embodiment illustrated in Fig. 40. More specifically, the preheating device 81 is connected to a through-hole-shaped supply port 11a provided on a part of the circumference of the rear end of the cylinder 11 as illustrated in Fig. 63, and supplies molding material Mm, such as resin pellets having substantially spherical or cylindrical shapes or other shapes, to the supply port 11a.

[0314] In the third embodiment, the preheating device 81 has a material feed passage 82 through which the molding material Mm passes, as shown in Fig. 64. The material feed passage 82 is defined by the inner circumferential surface of a tubular body 83, such as a pipe made of metal (in other words, the material feed passage 82 is formed inside the tubular body 83). The material feed passage 82 has a junction 82a where the molding material Mm and the heating medium Gh join together, and an in-line mixing section 82b that mixes the molding material Mm and the heating medium Gh that have joined at the junction 82a and heats the molding material Mm with the heating medium Gh. Therefore, as shown in Figure 64, the molding material Mm is supplied to the supply port 11a of the cylinder 11 through the material feed passage 82 from upstream (left side of Figure 64) to downstream (right side of Figure 64) in the material passing direction, and along the way passes through a junction section 82a where it merges with the heating medium Gh, and then a mixing section 82b where the molding material Mm and the heating medium Gh are mixed.

[0315] In the preheating device 81 having such a configuration, the molding material Mm to be supplied inside the cylinder 11 can be preheated before being supplied. As a result, the preheated molding material Mm is supplied into the cylinder 11 through the supply port 11a, and then sufficiently melted inside the cylinder 11 within a short period of time, and then injected from the tip of the cylinder 11, thereby realizing a shortened molding cycle.

[0316] Here, in the illustrated example, the material feed passage 82 has a first portion 821 extending vertically (up-down in FIG. 64) from upstream to downstream in the material passing direction, a second portion 822 extending horizontally (left-right in FIG. 64) following the vertical lower end (downstream side in the material passing direction) of the first portion 821, and a third portion 823 extending vertically following the downstream side in the material passing direction of the second portion 822. At the vertical upper end of the first portion 821, the molding material Mm is supplied into the material feed passage 82, and the second portion 822 has a junction portion 82a and a mixing portion 82b, and the third portion 823 is connected at its vertical lower end to a supply container 26 described later. The size of the material feed passage 82 can be arbitrarily determined depending on the amount of molding material Mm to be transported, the heating temperature, etc. Also, the shape of the material feed passage 82 is not limited to that shown in Fig. 64, and can be any shape. Furthermore, a heat insulating material can be provided around the tubular body 83 that forms the material feed passage 82.

[0317] The confluence 82a in the material feed passage 82 is the point where the heating medium Gh heated in the heating section 84 is sent from the heating section 84 through the heat medium feed passage 84a and merges with the molding material Mm being transported from upstream to downstream in the material passing direction. The heating medium Gh may be a heating gas, specifically, a gas such as air or an inert gas that has been heated, or superheated steam. However, the heating medium Gh is not particularly limited as long as it can merge with the molding material Mm at the merging portion 82a and flow downstream in the material passing direction. The heating medium Gh is heated by the heating portion 84 of the preheating device 81, and the heating portion 84 may be, for example, a hot air heater. The hot air heater may be, for example, a heater that heats compressed air sent from a compressor with a sheath heater or the like to obtain hot air. The temperature of the hot air can be adjusted by changing the output of the sheath heater. The heating medium Gh is sent to the merging portion 82a through the heat medium sending passage 84a of the preheating device 81, and the heat medium sending passage 84a between the heating portion 84 and the merging portion 82a may be partitioned by, for example, a pipe 84b made of metal and surrounded by a heat insulating material.

[0318] The heating medium Gh is produced in the heating section 84, and then sent to the junction 82a of the material sending passage 82 via the heating medium sending passage 84a in FIG. As described above, at the confluence 82a, the heat transfer medium feed passage 84a branches off from the material feed passage 82, but between the confluence 82a and the heat transfer medium feed passage 84a, a passage prevention section such as a mesh can be provided to prevent the molding material Mm from being fed to the heat transfer medium feed passage 84a.

[0319] The mixing section 82b is a section where the molding material Mm and the heating medium Gh that have joined at the joining section 82a are mixed in-line and the molding material Mm is heated by the heating medium Gh. By providing the joining section 82a, the molding material Mm and the heating medium Gh join at the joining section 82a and are sent in the material passing direction together with the heating medium Gh, so that the molding material Mm and the heating medium Gh come into contact with each other, and the molding material Mm can be partially heated. However, the molding material Mm is not heated sufficiently uniformly and efficiently in a short time by only contacting with the heating medium Gh. Therefore, by providing the mixing section 82b in the material feed passage 82, the flow of the molding material Mm and the heating medium Gh can be homogenized, and the molding material Mm can be heated uniformly. In addition, by effectively mixing, the molding material Mm is sufficiently heated from the entire surface, enabling high-speed heating.

[0320] As the mixing section 82b, in the example of Fig. 64, a static mixer that is an in-line mixer without a drive section is used. The static mixer in the illustrated example specifically includes a plurality of spirally twisted plates 82c provided in the material feed passage 82. By including such spiral plates 82c, the flow of the molding material Mm and the heating medium Gh passes through the mixing section 82b while being divided, diverted, and reversed, and the molding material Mm can be efficiently and uniformly heated in a short time.

[0321] As shown in FIG. 65 (two plates are shown in FIG. 65), the spiral plate 82c has a spiral shape formed by twisting a flat plate about 180° around an axis, and the spiral plate 82c is arranged so that the axis is along the material passing direction in the material feed passage 82. Adjacent spiral plates 82c have opposite twist directions around the axis, and the ends of the plates 82c are joined in a direction that is approximately perpendicular to each other. A static mixer including such a spiral plate 82c preferably includes a plurality of the spiral plates 82c, which allows the molding material Mm and the heating medium Gh to be effectively mixed. The spiral plate 82c can be made of metal. However, the static mixer is not limited to the spirally twisted plate 82c as described above, and may be any type that can increase the contact efficiency between the molding material Mm and the heating medium, for example, by changing the flow direction of the heating medium and / or partially narrowing the material feed passage 82. In the third embodiment, the mixer 82b is not limited to the above mixer, and any mixer can be used as long as it can mix the molding material Mm and the heating medium Gh in-line, and may or may not have a drive unit. Also, a mixer capable of in-line mixing without a drive unit is preferable. By using such a mixer, for example, the mixer can be installed in an existing conveying path for the molding material Mm as the material feed passage 82, and the equipment introduction cost can be reduced.

[0322] The preheating device 81 of the third embodiment is provided with a conveyor 85 that conveys the molding material Mm from the upstream to the downstream of the material feed passage 82, and in the example of Fig. 64, the conveyor 85 is a gas pump that pumps the molding material Mm. More specifically, the gas pump 85 introduces compressed gas Gp produced by a compressor (not shown) or the like into the gas pump 85 as shown in Fig. 66, and generates a discharge-side gas flow Gb from the compressed gas Gp toward the downstream side of the material passing direction of the material feed passage 82 (the right side in Fig. 66) (in other words, the discharge port for generating the discharge-side gas flow Gb faces the downstream side of the material passing direction), so that the upstream side (the left side in Fig. 66) of the discharge part that discharges the compressed gas Gp into the discharge-side gas flow Gb becomes negative pressure. This generates a suction-side gas flow Gf that is sucked downstream upstream of the gas pump 85 in the material passing direction, and transports the molding material Mm present on the upstream side of the material feed passage 82 in the material passing direction downstream. 64, in the third embodiment, the gas pump 85 is provided upstream of the junction 82a in the material feed passage 82, so that the gas pump 85 sucks and transports the molding material Mm present upstream in the material feed passage 82 in the material passing direction to the junction 82a, and then passes the molding material Mm together with the heating medium Gh through the mixing section 82b and pumps and transports the molding material Mm to the downstream side of the material feed passage 82. Also, by providing the gas pump 85 upstream of the junction 82a in the material feed passage 82, it is possible to prevent the heating medium Gh from flowing back upstream in the material passing direction. By using a gas pressure feeder for pressure-feeding the molding material Mm as the conveyor 85 in this manner, for example, an existing conveying path for the molding material Mm can be used, and the equipment introduction cost can be reduced. When a gas pressure feeder is used as the conveyor 85, the compressed gas Gp is ​​not particularly limited and air can be used. In addition, the material feed passage 82 can be provided with an outlet (not shown) for discharging the heating medium Gh, downstream in the material passing direction and before the supply port 11a of the cylinder 11, for example, in the supply container 26 in the example shown in Fig. 41, and the outlet can also be used to exhaust the gas from the gas pressure feeder 85 introduced for conveyance.

[0323] In addition, in the first modified example of the third embodiment, in the preheating device 181, a gas compressor as a conveying device 185 is provided downstream in the material passing direction of the mixing section 182b in the material feed passage 182 as shown in FIG. 67, and the molding material Mm can be conveyed via the junction 182a and the mixing section 182b in the material feed passage 182 by the downstream suction force generated upstream in the material passing direction of the gas compressor 185. In the second modified example of the third embodiment, instead of the above-mentioned gas pressure feeder, a feed screw 285 is used as a conveyor 285 in the preheating device 281 as shown in FIG. 68. By providing the feed screw 285 upstream of the material passing direction of the material feed passage 282, the molding material Mm can be conveyed through the junction 282a and the mixing section 282b so as to be pushed out of the material feed passage 282. The feed screw 285 shown in FIG. 68 includes a screw 285a that rotates the molding material Mm to move it, a cylindrical cylinder 285b that contains the screw 285a, and a drive unit 285c that rotates the screw 285a. In addition, a supply container 227 (hopper) is connected to an opening 285d on the drive unit 285c side of the cylinder 285b of the feed screw 285, and the molding material Mm is supplied from the supply container 227. Furthermore, in the feed screw 285, the material feed passage 282 is connected to an opening 285e on the tip side of the cylinder 285b, and the molding material Mm is fed into the material feed passage 282 from the opening 285e.

[0324] In the third embodiment, a supply container 26 for supplying a cylinder such as a hopper is provided on the downstream side (lower end side of FIG. 64) of the material passing direction of the material feed passage 82. In the illustrated example, the supply container 26 has, for example, a truncated cone-shaped portion 26a whose inner and outer shapes are both truncated cones, and a cylindrical portion 26b formed at the end of the small diameter side of the truncated cone-shaped portion 26a. The supply container 26 receives the molding material Mm that has passed through the material feed passage 82 in the truncated cone-shaped portion 26a, and then supplies the molding material Mm through the cylindrical portion 26b at the end of the truncated cone-shaped portion 26a to the inside of the cylinder 11. An opening 26c having a width approximately the same as that of the material feed passage 82 is formed at the end of the truncated cone-shaped portion 26a, and the molding material Mm that has passed through the material feed passage 82 enters the supply container 26 from the opening 26c.

[0325] In addition, upstream of the material passing direction of the material feed passage 82, a supply container 27 for supplying the passage, such as a hopper, which stores multiple molding materials Mm and supplies the molding materials Mm in an appropriate amount to the material feed passage 82, is placed in front of the conveyor 85.

[0326] In the illustrated example, the molding material Mm is supplied from the supply container 27 for supplying the passage to the preheating device 81. The molding material Mm supplied to the preheating device 81 passes through the material feed passage 82 while being preheated, and is supplied to the inside of the cylinder 11 after passing through the supply container 26 for supplying the cylinder. That is, here, the molding material Mm preheated by the preheating device 81 is supplied to the inside of the cylinder 11. However, the shape of the supply container 26 and / or the supply container 27 is not limited to this, and can be appropriately changed, and the supply container 26 and / or the supply container 27 may be omitted. If the supply container 26 for the cylinder is omitted, the preheating device is disposed on the cylinder, and the tip side of the material feed passage in the material passing direction is directly connected to the supply port of the cylinder. In this case, the molding material Mm preheated by the preheating device is supplied to the inside of the cylinder immediately after the preheating.

[0327] In the third embodiment shown in FIG. 64, as the plasticization by the screw 12 or the like inside the cylinder 11 progresses, the molding material Mm is supplied from the supply container 26 for supplying the cylinder to the inside of the cylinder 11. Accordingly, the molding material Mm in the supply container 27 for supplying the passage passes through the material feed passage 82, is heated by the heating unit 84, and then is fed into the supply container 26 for supplying the cylinder. In this case, the speed of the molding material Mm passing through the material feed passage 82 may depend on the speed of plasticization of the molding material Mm inside the cylinder 11, but the passing speed of the molding material Mm can also be adjusted by the conveyor 85 as described above. In addition, in order to adjust the speed at which the molding material Mm passes through the material feed passage 82 and the degree of heating of the molding material Mm affected by it, a screw-shaped feeder or other supply adjuster for adjusting the supply of the molding material Mm from the material feed passage 82 to the supply container 26 may be provided between the material feed passage 82 and the supply container 26, although not shown in the figure.

[0328] Incidentally, as described above, the preheating device 81 has a cooling section (not shown) that cools the molding material Mm passing through the material feed passage 82. In detail, the cooling section can be disposed outside the tubular body 83 that divides the material feed passage 82 as shown in Fig. 64, and by using piping or the like that extends from the cooling section to the inside of the material feed passage 82 or the heat medium feed passage 84a, the cooling medium generated in the cooling section can be caused to flow into the material feed passage 82 to cool the molding material Mm passing through the material feed passage 82. The cooling medium generated by the cooling section may be not only cold air but also air at a temperature lower than the molding material Mm, for example, air at room temperature. The cooling section may be provided in the preheating device 81, but can be realized by making the heating section 24 structured to send room temperature gas such as cold air or cooling gas Gc.

[0329] Furthermore, the preheating devices 81, 181, 281 of the third embodiment can be controlled in the same manner as the preheating device 21 of the first embodiment described above. That is, the preheating devices 81, 181, 281 can further include a control unit that controls the heating unit 84 and / or the cooling unit. More specifically, the control unit can control the heating unit 84 and / or the cooling unit based on signals obtained by the operation state detection mechanism, the retention detection mechanism, and / or the temperature information detection mechanism.

[0330] The operation state detection mechanism of the third embodiment detects the operation state of the injection device 1 when the operation of the injection molding machine stops for some reason, for example. The detection can be performed by providing a transmitter that transmits the operation status of the injection device 1, more specifically, a transmitter that transmits the operation status of the metering motor 31 and the injection motor 41 of the injection device 1. In addition, the retention detection mechanism detects information regarding retention of the molding material Mm when, for example, for some reason, the molding material Mm is retained in the material feed passage 82. The detection can be performed by using a sensor that detects retention of the molding material Mm in the material feed passage 82.

[0331] That is, in the third embodiment, the preheating device 81 is preferably provided with a retention detection mechanism (not shown) that detects retention of the molding material Mm in the material feed passage 82. The retention detection mechanism may be, for example, a sensor that detects retention based on temperature or the like. By providing the retention detection mechanism, it is possible to detect early on an excessive rise in the temperature of the molding material Mm, for example, when the molding material Mm is retained. Note that the temperature of the molding material Mm referred to here may be the temperature of the molding material Mm itself, the temperature in the space in the material feed passage, or the temperature of the tubular body that forms the material feed passage. Such a sensor of the retention detection mechanism is preferably provided at the confluence portion 82a or the mixing portion 82b of the material feed passage 82, or at a location near the downstream side thereof.

[0332] In addition, when the sensor of the retention detection mechanism is a temperature sensor, it can be used in combination with a temperature sensor that can be used in a temperature information detection mechanism that can be provided in the preheating device 81. In other words, when it is used in combination with a temperature sensor, the preheating device 81 detects retention of the molding material Mm using a temperature sensor as a retention detection mechanism, and the control unit can stop heating by controlling the heating unit 84 based on the detection of retention of the molding material Mm obtained by the retention detection mechanism. Then, when the temperature information detection mechanism detects information on the temperature of the molding material Mm in the material feed passage 82, specifically, for example, when the temperature of the molding material Mm measured by the temperature sensor meets a predetermined standard, the control unit can control the cooling unit to cool the molding material Mm based on the information on the temperature.

[0333] In addition, in the preheating device 81, for example, a temperature sensor can be provided in the material feed passage 82 so that the temperature information detection mechanism can detect information related to temperature (as described above, when the sensor of the retention detection mechanism is used as a temperature sensor, it may also serve as the temperature sensor). More specifically, it is preferable to provide such a temperature sensor at the junction 82a or mixing section 82b of the material feed passage 82, or at a location near the downstream side thereof. The temperature of the molding material Mm referred to here can be the temperature of the molding material Mm itself, the temperature in the space in the material feed passage, or the temperature of the tubular body that forms the material feed passage.

[0334] (injection device) An injection device 1 to which the above-mentioned preheating device 21 and the like can be applied mainly comprises, as exemplified in FIG. 40 and the like, the preheating device 21, a cylinder 11 which melts the molding material supplied from the preheating device 21 therein, a screw 12 which is driven to rotate inside the cylinder 11 to plasticize the molding material, a metering motor 31 arranged on the rear side in the direction of the rotation axis of the screw 12 (the right side in FIG. 40), and an injection motor 41 arranged further rearward of the metering motor 31.

[0335] A heater 13 is arranged around the cylinder 11 to heat the molding material plasticized by the screw 12 inside the cylinder 11. The cylinder 11 has a tip portion 14 with smaller inner and outer diameters at the tip side in the rotation axis direction (left side in Fig. 40), and heaters 13 are also arranged around the tip portion 14. In addition, a through-hole-shaped supply port 11a is provided at the rear end side in the rotation axis direction of the cylinder 11, and the above-mentioned preheating device 21 is attached thereto.

[0336] The metering motor 31 and the injection motor 41 are fixed to the rear surfaces of the rear ends in the rotation axis direction of two motor support plates 32, 42, which are arranged at a distance from each other in an upright position on the slide base 101. The screw 12 is driven to rotate by the metering motor 31, and driven to move forward and backward by the injection motor 41. The two motor support plates 32, 42 are connected to each other by rods 51, 52 at multiple points on the upper and lower sides separated by the metering motor 31.

[0337] The metering motor 31 mainly includes a rotor 33, a stator 34 arranged around the rotor 33, and a stator frame 35 that surrounds the rotor 33 and the stator 34 and has the stator 34 provided on its inner surface. The rotor 33 of the metering motor 31 is supported by bearings 33a inside the stator frame 35 at each end in the direction of its rotation axis. The rotor 33 is splined around a metering spline shaft 36, and the metering spline shaft 36 is connected to a screw mounting portion 37 to which the screw 12 is attached. At the rear end in the direction of the rotation axis of the outer circumferential surface of the metering spline shaft 36, one or more keys 36a corresponding to the key grooves provided on the inner circumferential surface of the rotor 33 are formed. This allows a rotational driving force to be transmitted from the metering motor 31 to the screw 12, thereby rotating the screw 12.

[0338] The injection motor 41 mainly includes a rotor 43, a stator 44 arranged around the rotor 43, and a stator frame 45 that is provided around the rotor 43 and the stator 44 and has the stator 44 on its inner surface. The rotor 43 is supported by bearings 43a inside the stator frame 45 at each end in the direction of its rotation axis. In the injection motor 41, the rotor 43 is connected to a drive shaft. More specifically, the drive shaft includes an injection spline shaft 46 splined at a groove 43b provided on the inner periphery of the cylindrical rotor 43, a threaded shaft 48 connected to the injection spline shaft 46, and a rotating shaft 50 rotatably attached to the inside of the metering spline shaft 36 via a bearing 49. A threaded nut 47 that screws onto the threaded shaft 48 is attached to the motor support plate 42 via a pressure detector 38, which will be described later. With this structure, the rotational driving force of the injection motor 41 is converted into a linear driving force in the direction of the rotation axis of the screw 12 and transmitted to the screw 12 .

[0339] A pressure detector 38 is disposed between the stator frame 45 of the injection motor 41 and the motor support plate 42. The pressure detector 38 is attached to the motor support plate 42 and the screw nut 47, and detects the load acting on the pressure detector 38 in the transmission path of the driving force from the injection motor 41 to the screw 12. A cylindrical portion 39 is provided between the pressure detector 38 and the stator frame 45. Further, an encoder 45a that is connected to the rotor 43 by a shaft portion 45b and detects the rotation of the rotor 43 is provided on the rear end surface of the stator frame 45 of the injection motor 41, which is located on the opposite side to the drive shaft in the rotation axis direction.

[0340] When the injection device 1 is equipped with the above-mentioned preheating device 21 or the like, the control unit for controlling the heating unit 24 and / or the cooling unit may be provided in the injection device 1 instead of in the preheating device 21. When the injection device 1 is equipped with a control unit for controlling the heating unit 24 and / or the cooling unit instead, the control unit can perform the same control as that performed by the control unit when the preheating device 21 is equipped with the control unit.

[0341] To give an example of a molding process using an injection molding machine equipped with such an injection unit 1, a mold clamping process is performed in which a mold unit (not shown) is closed to clamp the mold, with a predetermined amount of molding material already measured and placed inside the cylinder 11 in the latter half of the previous molding process. Next, a filling process is performed in which the molding material is injected into the mold unit by advancing the screw 12 to fill the cavity in the mold unit with the molding material, and a pressure holding process is performed in which the molding material inside the tip 14 of the cylinder 11 is maintained at a predetermined pressure by further advancing the screw 12.

[0342] Then, a cooling process is performed in which the molding material filled in the mold device is cooled and hardened to obtain a molded product. At this time, a measuring process is performed in which the molding material separately supplied from the preheating device 21 into the cylinder 11 is melted while being sent toward the tip 14 of the cylinder 11 by the rotation of the screw 12 under heating by the heater 13, and a predetermined amount of the molding material is placed at the tip 14.

[0343] Here, in the first, second and third embodiments, the molding material supplied into the cylinder 11 has already been heated to an appropriate temperature by the preheating devices 21, 60 and 81. Therefore, even if the screw 12 is rotated at high speed and the molding material is sent to the tip 14 of the cylinder 11 in a short time, the molding material can be sufficiently plasticized. This shortens the time required for metering, and makes it possible to shorten the molding cycle.

[0344] After that, the mold assembly is opened to bring it into an open state, and an ejection step is performed in which the molded product is ejected from the mold assembly by an ejector device or the like. [Explanation of symbols]

[0345] 1 Injection device 11 Cylinders 11a Supply port 12 Screw 13 Heater 14 Tip 21, 121, 221 Preheating device 22, 122, 222 Material feed passage 22a Passage partition member 22b Movable parts 23, 123, 223 Passage forming members 223a Conveyor belt 223b Lola 23a Board material 23b Ventilation hole 23c wire rod 23d Sensor 24, 124, 224 Heater, heating unit 25, 125 case 26, 27, 126, 127, 226, 227 supply container 26a, 126a, 226a Cone-shaped part 26b, 126a, 226b Cylindrical part 26c, 126c, 226c opening 27a Cylinder part 27b Tapered section 28 Impact applying section 28a through hole 28b Plate-shaped member 28c Pin-shaped member 29 Vibration applying section 30 Blower section 31 Metering motor 32 Motor support plate 33 Rotor 33a Bearing 34 Stator 35 Stator frame 36 Metering spline shaft 36a Key 37 Screw mounting part 38 Pressure detector 39 Cylindrical part 41 Injection motor 42 Motor support plate 43 Rotor 43a Bearing 43b Groove 44 Stator 45 Stator Frame 45a Encoder 45b Shaft 46 Injection spline shaft 47 Screw Nut 48 Screw shaft 49 Bearings 50 Rotational Axis 51, 52 Rod 60, 260, 360, 460 Preheating device 61, 361, 461 Material aisle 61a Passage entrance 61b Hopper 61c, 361c passage exit 62, 162, 262, 462 Superheated steam inlet 63, 163, 263, 363, 463 Passage partition wall 63a opening 64, 164, 364 Preheating screw 65, 165 Rotation axis 66, 166 Flights 67 Drive unit 68 Interior Space 69 Peripheral wall section 70 Communication hole 81, 181, 281 Preheating device 82, 182, 282 Material feed passage 821 Part 1 822 Part 2 823 Part 3 82a, 182a, 282a confluence 82b, 182b, 282b mixing section 82c board 83 Tubular body 84 Heater, heating section 84a Heat transfer passage 84b Piping 85, 185, 285 Conveyor 285a Screw 285b Cylinder 285c Drive unit 285d, 285e opening 101 Slide Base Mm molding material Gh Heating gas, heating medium Gc Cooling gas Gp Compressed gas Gb Discharge side gas flow Gf Suction side gas flow Ss Superheated steam Tm Melting point of molding material Tu upper limit

Claims

1. A preheating device for preheating a molding material, The preheating device is a material feed passage through which the molding material passes; A heater for heating the molding material passing through the material feed passage; having The material feed passage includes a pair of passage forming members disposed opposite each other and defining the material feed passage therebetween; At least one of the pair of passage forming members is movable, so that the passage width between the passage forming members can be adjusted.

2. 2. The preheating device according to claim 1, further comprising a supply container for receiving the molding material passed through the material feed passage and supplying the molding material to the inside of a cylinder of the injection device.

3. 3. The preheating device according to claim 1, further comprising a retention prevention mechanism for preventing retention of the molding material in the material feed passage.

4. A preheating device as described in claim 1, further having a superheated steam inlet for introducing superheated steam into the material feed passage to heat the molding material in the material feed passage.

5. 5. The preheating device according to claim 4, further comprising a conveying mechanism for conveying the molding material in the material feed passage in a material passing direction.

6. Further, a cooling section for cooling the molding material passing through the material feed passage, The preheating device according to claim 1 , further comprising a control unit that controls the heater and / or the cooling unit.

7. The preheating device further includes an operation state detection mechanism for detecting an operation state of the injection device, 7. The preheating device according to claim 6, wherein the control unit performs control based on information regarding the stop of operation of the injection device detected by the operation state detection mechanism.

8. A retention detection mechanism for detecting retention of molding material in the material feed passage is further provided, 8. The preheating device according to claim 6, wherein the control unit performs control based on information regarding the retention of the molding material detected by the retention detection mechanism.

9. A temperature information detection mechanism for detecting information regarding the temperature of the molding material in the material feed passage is further provided.

9. The preheating device according to claim 6, wherein the control unit performs control based on information regarding the temperature of the molding material detected by the temperature information detection mechanism.

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