Injection device and injection molding machine equipped therewith

Abstract

An injection device 3 comprises: an injection cylinder 31 having a supply part 312 to which an injection material is supplied, and a recessed part 313; and a heater 11 for heating the injection cylinder 31. Both ends of the recessed part 313 in the axial direction X of the injection cylinder 31 are located between the supply part 312 and the heater 11, and the recessed part 313 is recessed inward in the radial direction of the injection cylinder 31 from two adjacent parts that are adjacent to the recessed part 313. The injection cylinder 31 has a reinforcing rib 315, and the reinforcing rib 315 is provided radially outside the recessed part 313 so as to be contiguous with the two adjacent parts and the recessed part 313.

Description

Injection Apparatus and Injection Molding Machine Including Same

[0001] This application claims priority based on Japanese Patent Application No. 2025-30254 filed on February 27, 2025 and Japanese Patent Application No. 2025-248400 filed on December 15, 2025. The entire contents of these applications are incorporated herein by reference. The present disclosure relates to an injection apparatus and an injection molding machine including the injection apparatus.

[0002] Japanese Unexamined Patent Publication No. 2016-2696 describes an injection apparatus for an injection molding machine. The injection apparatus includes a heating cylinder that accommodates a screw (hereinafter referred to as an injection cylinder) and a heater that heats the injection cylinder. The injection cylinder includes a supply portion to which an injection material is supplied, and the injection material supplied from the supply portion is heated by the heater and melted.

[0003] The supply portion of the injection cylinder is heated when heat generated by the heater is transferred to the injection cylinder. If the supply portion is excessively heated, the injection material may soften or melt in the supply portion and cannot be stably supplied to the injection cylinder. However, if the heat generation amount of the heater is reduced, the injection material cannot be sufficiently heated.

[0004] An object of the present disclosure is to provide an injection apparatus that enables stable supply of an injection material while sufficiently heating the injection material.

[0005] The injection apparatus includes an injection cylinder having a supply portion to which an injection material is supplied and a drawing portion, and a heater that heats the injection cylinder. Both ends of the drawing portion in the axial direction of the injection cylinder are located between the supply portion and the heater. The injection cylinder has a reinforcing rib continuous with the drawing portion, or a reinforcing portion for the drawing portion that is spaced apart from the drawing portion.

[0006] According to the present disclosure, an injection apparatus that enables stable supply of an injection material while sufficiently heating the injection material can be provided. The above-described and other objects, features, and advantages of the present application will become apparent from the detailed description set forth below with reference to the accompanying drawings that illustrate examples of the present application.

[0007] This is a schematic front view of an injection molding machine according to the first embodiment. This is a schematic front view of the injection device of the injection molding machine shown in Figure 1. This is a partially enlarged view of the injection device shown in Figure 2. This is a partially exploded perspective view of the injection device shown in Figure 2. This is an enlarged view of the retraction section. This is a cross-sectional view of the retraction section shown in Figure 5A. This is a cross-sectional view of a modified example of the retraction section. This is a cross-sectional view of another modified example of the retraction section. This is an enlarged view of the retraction section of an injection device according to the second embodiment. This is a cross-sectional view of a modified example of the retraction section shown in Figure 6A. This is a cross-sectional view of a modified example of the retraction section. This is an enlarged view of the retraction section of an injection device according to a modified example of the second embodiment. This is a cross-sectional view of the retraction section shown in Figure 7A. This is a partially enlarged view of an injection device according to the third embodiment. This is a partially exploded perspective view of the injection device shown in Figure 8. This is a plan view of the hopper flange of an injection device according to a modified example of the third embodiment. This is a partially enlarged view of an injection device according to a modified example of the fourth embodiment. This is a partially enlarged view of an injection device according to a modified example of the fourth embodiment. This is a perspective view of the hopper flange of an injection device according to the fifth embodiment. This is a partially enlarged view of an injection device according to a modified example of the sixth embodiment. This is a partially enlarged view of an injection device according to a modified example of the sixth embodiment. This is a schematic front view of an injection device according to the seventh embodiment. This is a schematic cross-sectional view of an injection device according to the seventh embodiment.

[0008] Hereinafter, several embodiments of the present disclosure will be described with reference to the drawings. The embodiments described below relate to a horizontal injection molding device for injecting resin and a horizontal injection molding machine equipped therewith, but the present disclosure can also be applied to vertical injection molding devices and metal injection molding devices. In the following description and drawings, the axial direction of the injection cylinder and screw is referred to as the X direction. The X direction is parallel to the horizontal direction. The direction from the injection molding device toward the clamping device, or the injection direction, is referred to as the +X direction, and the direction from the clamping device toward the injection molding device is referred to as the -X direction. The direction perpendicular to the X direction and parallel to the horizontal direction is referred to as the Y direction, and the vertical direction is referred to as the Z direction.

[0009] <First Embodiment> Figure 1 shows a schematic front view of an injection molding machine 1 according to the first embodiment. Figure 2 shows a schematic front view of the injection device 3 of the injection molding machine 1 shown in Figure 1. The injection molding machine 1 is generally composed of a mold clamping device 2 that supports the mold and opens and closes the mold, and an injection device 3 that heats and melts the material to be injected (for example, resin pellets, hereinafter referred to as injection material) and injects it.

[0010] <Mold Clamping Device 2> As shown in Figure 1, the mold clamping device 2 includes a fixed platen 22 fixed on the bed 21 to which a fixed mold M1 is attached, a mold clamping housing 24 that can slide on the bed 21, and a movable platen 23 that can slide on the bed 21 to which a movable mold M2 is attached. The fixed platen 22 and the mold clamping housing 24 are connected by a plurality of tie bars 25. A mold clamping mechanism 26 for opening and closing the mold is provided between the movable platen 23 and the mold clamping housing 24. The mold clamping mechanism 26 is composed of a toggle mechanism, but may also be composed of a hydraulic mold clamping injection cylinder.

[0011] <Injection device 3> The injection device 3 is mounted on a base 35. The injection device 3 comprises an injection cylinder 31, a screw 32 housed in the injection cylinder 31 that kneads and plasticizes the injection material, a drive mechanism 33 that drives the screw 32, and a nozzle touch device 34 that drives the injection cylinder 31. The injection cylinder 31 is generally cylindrical or disc-shaped, and has an internal space that houses the screw 32 and through which the injection material flows. An injection nozzle 36 for injecting the injection material is provided at the tip of the injection cylinder 31 in the +X direction. The drive mechanism 33 is covered by a cover 37. The nozzle touch device 34 drives the drive mechanism 33, the injection cylinder 31, etc. together in the X direction.

[0012] <Drive Mechanism 33> As shown in Figure 2, the drive mechanism 33 comprises a front plate 331, an intermediate plate 332, a rear plate 333, and a support plate 334. The front plate 331 and the rear plate 333 are fixed to the support plate 334. The intermediate plate 332 is supported so as to be movable in the X direction relative to the support plate 334. The support plate 334 is supported so as to be movable in the X direction on a base 35. The front plate 331 supports a hopper flange 38, which will be described later, and supports the injection cylinder 31 via the hopper flange 38. The intermediate plate 332 rotatably supports the screw 32. The front plate 331 has a through hole 3313 through which the screw 32 passes.

[0013] The drive mechanism 33 rotates the screw 32 around the central axis 32C using a plasticizing motor 335 provided on the intermediate plate 332. The drive mechanism 33 has a ball screw 336 located between the rear plate 333 and the intermediate plate 332. The ball screw 336 is rotatably supported on the rear plate 333 via a bearing 337. The drive mechanism 33 rotates the ball screw 336 using an injection motor 338 provided on the rear plate 333, thereby driving the intermediate plate 332 and the screw 32 in the X direction.

[0014] <Heater 11 and Insulation Material 12> The injection device 3 has a heater 11 that covers the outer surface of the injection cylinder 31. The heater 11 heats the injection cylinder 31, thereby heating and melting the injection material in the internal space of the injection cylinder 31. The heater 11 is, for example, an electric band heater and can be installed in sections in the X direction. The heater 11 is not limited to a band heater and may be a rod heater inserted into a hole formed in the injection cylinder 31, etc. The injection device 3 has an insulation material 12 that covers the outer surface of the heater 11. As the insulation material 12, a cylinder protection material made of insulating material such as glass wool wrapped in a heat-resistant jacket can be used. The insulation material 12 can also be omitted.

[0015] <Hopper 5 and Hopper Flange 38> Figure 3 shows a partially enlarged view of the injection cylinder 31, hopper flange 38, hopper 5, and front plate 331, and Figure 4 shows an exploded perspective view of a part of the injection cylinder 31, hopper flange 38, and front plate 331. The injection device 3 includes a hopper 5 that supplies injection material to the injection cylinder 31, and a hopper flange 38 that supports the hopper 5 and the injection cylinder 31. The hopper 5 is provided near the -X end of the injection cylinder 31. The hopper 5 is made of a thin metal plate that is roughly funnel-shaped, with the upper opening 51 being the injection material input section and the lower opening 52 being the injection material discharge section.

[0016] As shown in Figure 4, the hopper flange 38 has a cylindrical portion 381 and a flange portion 382. The hopper flange 38 can be made of, for example, cast iron, and the cylindrical portion 381 and the flange portion 382 are integrated. The cylindrical portion 381 has a through hole 387, the diameter D1 of which is approximately equal to the outer diameter D2 of the injection cylinder 31, and the injection cylinder 31 is fixed or supported in the through hole 387 of the cylindrical portion 381 by shrink fitting. The injection cylinder 31 may be attached to the hopper flange 38 by other means. The flange portion 382 and the front plate 331 each have a plurality of through holes 383, 3311, and the hopper flange 38 is fixed to the front plate 331 by inserting bolts into these through holes 383, 3311. Thus, the injection cylinder 31 is supported by the front plate 331 via the hopper flange 38.

[0017] As shown in Figures 3 and 4, the cylindrical portion 381 has a through hole 384 that communicates with the lower opening 52 of the hopper 5, and the injection cylinder 31 has a through hole 311 that communicates with the through hole 384 of the cylindrical portion 381. The injection material is supplied from the lower opening 52 of the hopper 5 through the through hole 384 of the cylindrical portion 381 and the through hole 311 of the injection cylinder 31 to the internal space of the injection cylinder 31. The through hole 311 of the injection cylinder 31 constitutes a supply section 312 to which the injection material is supplied from the hopper 5. Although not shown in the figures, the hopper flange 38 may be provided adjacent to the injection cylinder 31 in the X direction. In this case, the hopper flange 38 has an internal space that communicates with the internal space of the injection cylinder 31 and becomes part of the injection cylinder 31.

[0018] As shown in Figure 3, the cylindrical portion 381 of the hopper flange 38 is provided with a cavity 385 through which cooling water flows to cool the hopper flange 38. The cavity 385 is connected to a cooling water passage 61. Because the hopper flange 38 is cooled by the cooling water, the injection material is less likely to soften or melt in the through-hole 384 of the hopper flange 38. The vicinity of the through-hole 311 of the injection cylinder 31 is also cooled by the cooling water, so the injection material is less likely to soften or melt in the through-hole 311 of the injection cylinder 31. This ensures a more stable supply of injection material to the injection cylinder 31. A throttle valve 62 is provided in the cooling water passage 61 to adjust the flow rate of the cooling water.

[0019] <Thermal insulation structure of injection cylinder 31> Figure 5A is an enlarged view of part A in Figure 3, showing the vicinity of the retraction section 313. The thermal insulation material 12 is not shown. As shown in Figures 2, 3, and 5A, the injection cylinder 31 has a retraction section 313 located between the supply section 312 and the heater 11 in the X direction, two adjacent sections 314A and 314B adjacent to the retraction section 313 on both sides of the retraction section 313 in the X direction, and a reinforcing rib 315 that reinforces the retraction section 313. In other words, the injection cylinder 31 has a notch 316 between the supply section 312 and the heater 11 in the X direction. The retraction section 313 has a cylindrical or disc shape, but may also have a polygonal prism shape.

[0020] Since both ends 313A and 313B of the retraction section 313 in the X direction are located between the supply section 312 and the heater 11 (the heater 11 closest to the supply section 312 when multiple heaters 11 are installed in series in the X direction), the heat Q transmitted through the injection cylinder 31 in the -X direction can be restricted by the supply section 312. In this embodiment, both ends 313A and 313B of the retraction section 313 in the X direction are located between the hopper flange 38 and the heater 11.

[0021] Figure 5B shows a cross-sectional view along the line 5B-5B in Figure 5A. The retraction portion 313 is retracted radially R inward from the two adjacent portions 314A and 314B of the injection cylinder 31. Radial R is the direction toward or away from the center of the injection cylinder 31 when viewed from the X direction, and coincides with the Z direction in Figures 2, 3, and 5A. The reinforcing rib 315 is provided radially R outward from the retraction portion 313. The reinforcing rib 315 is provided continuously with the opposing sides 314C and 313D of the two adjacent portions 314A and 314B and the retraction portion 313. The retraction portion 313 and the reinforcing rib 315 can be formed, for example, by machining a part of the injection cylinder 31.

[0022] If S1 is the cross-sectional area of ​​the section perpendicular to the X direction of the retraction section 313, S2 is the cross-sectional area of ​​the section perpendicular to the X direction of the reinforcing rib 315 (total cross-sectional area if multiple reinforcing ribs 315 are provided), and S3 is the cross-sectional area of ​​the sections perpendicular to the X direction of each adjacent section 314A, 314B, then S1 < S3 and S1 + S2 < S3. Therefore, the heat Q transmitted from the adjacent section 314A on the heater 11 side to the adjacent section 314B on the supply section 312 side is restricted. This suppresses the temperature rise of the supply section 312, and reduces the possibility that the injection material supplied from the supply section 312 will soften or melt and block the supply section 312.

[0023] As shown in Figure 5A, the radial distance D3 between the outer surface of the retraction section 313 and the outer surfaces of the two adjacent sections 314A and 314B is greater than the length D4 of the retraction section 313 in the X direction. In other words, the radial R dimension of the notch 316 is larger than the X dimension dimension. This makes it possible to more effectively regulate the heat Q passing through the retraction section 313, that is, the heat Q transmitted from the adjacent section 314A on the heater 11 side to the adjacent section 314B on the supply section 312 side.

[0024] The injection cylinder 31 is subjected to a downward bending moment due to its own weight (referred to as the self-weight moment), as well as a bending moment due to the reaction force of the nozzle touch force and the eccentricity of the injection nozzle 36 relative to the sprue bush (referred to as the eccentric moment), and an axial compressive force in the X direction due to the reaction force of the nozzle touch force. The reinforcing rib 315 can suppress the bending stress and compressive stress of the retraction portion 313 compared to when the reinforcing rib 315 is not present. In particular, since the reinforcing rib 315 is provided radially R outward from the retraction portion 313, the second moment of area can be effectively increased.

[0025] As shown in Figure 5B, multiple (five in this embodiment) reinforcing ribs 315 extend radially from the retraction portion 313 in the radial direction R. Since the direction of the eccentric moment depends on the direction of eccentricity, it may be difficult to predict or control. In this embodiment, the reinforcing ribs 315 are provided at equal angular intervals, so they act effectively against bending moments in any direction. However, the number and angle of the reinforcing ribs 315 are not limited, and it is sufficient to provide at least one reinforcing rib 315.

[0026] The configuration of the reinforcing ribs 315 is not limited to Figure 5B, and various deformations are possible. As shown in Figure 5C, two reinforcing ribs 315 may extend in the Z direction from the retraction portion 313. As shown in Figure 5D, in addition to the reinforcing ribs 315 shown in Figure 5C, there may be two more reinforcing ribs 315 extending in the Z direction from the top and bottom of the retraction portion 313, respectively. The reinforcing ribs 315 shown in Figures 5C and 5D act effectively against bending moments in the Z direction, such as the moment of self-weight.

[0027] Other embodiments will be described below. The description will mainly focus on the differences from the first embodiment. Configurations and effects that are not described are the same as in the first embodiment.

[0028] <Second Embodiment> Figure 6A shows a partially enlarged view of the injection cylinder 31, screw 32, and hopper flange 38 of the second embodiment, and Figure 6B shows a cross-sectional view along the line 6B-6B in Figure 6A. Similar to the first embodiment, the retraction portion 313 has a cylindrical or disc shape. Both ends 313A and 313B in the X direction of the retraction portion 313 are located between the hopper flange 38 and the heater 11. The injection cylinder 31 has a reinforcing portion 39A of the retraction portion 313. The reinforcing portion 39A is provided away from the retraction portion 313 in the radial direction R and extends over the entire circumference of the injection cylinder 31 in the circumferential direction C. The circumferential direction C is the direction of rotation around the center of the injection cylinder 31 when the injection cylinder 31 is viewed from the X direction. The two adjacent portions 314A and 314B have the same outer diameter, and the reinforcing portion 39A is an annular member having the same outer diameter as the two adjacent portions 314A and 314B.

[0029] Since the reinforcing portion 39A is located radially R outward from the reinforcing rib 315 of the first embodiment, it is easy to ensure strength against bending moments in all directions. In this embodiment, the reinforcing rib 315 of the first embodiment can be omitted, but it is also possible to provide the reinforcing rib 315. The cross-sectional area of ​​the reinforcing portion 39A required to obtain the same second moment of area as the reinforcing rib 315 is smaller than the cross-sectional area S2 of the reinforcing rib 315, which is also advantageous in terms of thermal insulation.

[0030] The reinforcing portion 39A and the two adjacent portions 314A and 314B can be fixed by welding. A welded portion 39B is provided between the reinforcing portion 39A and the two adjacent portions 314A and 314B. Specifically, the reinforcing portion 39A is divided into multiple members in the circumferential direction C, and each member is welded to the two adjacent portions 314A and 314B, and the members are fixed to each other by welding. Alternatively, the injection cylinder 31 may be formed by a 3D printer, in which case the welded portion 39B is unnecessary.

[0031] In this embodiment, the injection cylinder 31 has a sealed space 317 on the radially outer side R of the retraction portion 313. Since the space 317 is filled with air, there is no air convection, and the thermal insulation performance is improved by the thermal insulation performance of the air. An air vent hole may be provided in the reinforcing portion 39A, and the air vent hole may be sealed while the space 317 is under reduced pressure or vacuum, which further improves the thermal insulation performance.

[0032] As shown in Figure 6C, the reinforcing portion 39A may extend in the radial direction R away from the retracting portion 313, and only over a portion of the circumferential direction C of the injection cylinder 31. Since the reinforcing portion 39A of this modified example extends generally in the Z direction, it effectively acts against bending moments in the Z direction, such as the moment of self-weight. This modified example can be formed by machining, so welding is unnecessary.

[0033] <Modification of the Second Embodiment> Figure 7A shows a partially enlarged view of the injection cylinder 31 and hopper flange 38 of a modification of the second embodiment, and Figure 7B shows a cross-sectional view along the line 7B-7B in Figure 7A. The entire area of ​​the retraction portion 313 is covered by the hopper flange 38, and a sealed space 317 is formed between the injection cylinder 31 and the hopper flange 38. As described above, the hopper flange 38 is fixed to the injection cylinder 31 by shrink fitting, so the hopper flange 38 is in close contact with the injection cylinder 31 and resists bending deformation of the injection cylinder 31. In this modification, the hopper flange 38 functions as a reinforcing portion 39A, so the reinforcing portion 39A in Figure 6A can be omitted, and welding is not required. However, it is also possible to provide the reinforcing portion 39A in Figure 6A, and it is also possible to provide the reinforcing rib 315 of the first embodiment.

[0034] <Third Embodiment> Figure 8 is a partially enlarged view of the injection cylinder 31, screw 32, hopper flange 38, heat insulating plate 41, hopper 5, and front plate 331 of the third embodiment, and Figure 9 is an exploded perspective view of a part of the injection cylinder 31, hopper flange 38, heat insulating plate 41, and front plate 331. The injection device 3 of this embodiment has a heat insulating structure 40 that restricts heat transfer from the hopper flange 38 to the front plate 331. Specifically, a heat insulating plate 41 (an example of the heat insulating structure 40) is provided between the hopper flange 38 and the front plate 331. The heat insulating plate 41 is in contact with the hopper flange 38 and the front plate 331.

[0035] As shown in Figure 9, the insulation plate 41 has almost the same shape as the flange portion 382 of the hopper flange 38 and has an opening 411 through which the screw 32 passes and an opening 412 through which the bolt passes. The material of the insulation plate 41 is not limited as long as it has a lower thermal conductivity than the front plate 331 (usually made of iron), but examples include bakelite, resins such as engineering plastics, and ceramics.

[0036] As mentioned above, the heat transferred from the injection cylinder 31 to the hopper flange 38 is restricted by the retraction section 313, but some of the heat transferred to the hopper flange 38 is further transferred to the front plate 331. The heat transferred to the front plate 331 can, for example, heat the ball screw 336 and cause thermal deformation. If the ball screw 336 stretches due to thermal deformation, the positioning accuracy of the screw 32 in the X direction may decrease. Furthermore, this effect continues for a long period of time until the temperature of each part of the drive mechanism 33 becomes constant, which may cause molding to become unstable during that time.

[0037] In this embodiment, the transfer of heat from the injection cylinder 31 to the front plate 331 is restricted by the heat insulating plate 41, thereby mitigating the thermal impact on the ball screw 336. Furthermore, by providing the heat insulating plate 41, the amount of heat transferred from the injection cylinder 31 to the hopper 5 increases, resulting in the effect of heating and drying the injection material. This allows for the effective use of the heat from the heater 11, leading to energy savings.

[0038] <Modification of the Third Embodiment> Figure 10 shows a front view of the hopper flange 38 as seen from direction B in Figure 4, i.e., the surface of the hopper flange 38 facing the front plate 331 in a modification of the third embodiment. The hopper flange 38 has a facing surface 386 (see Figure 4) that faces the front plate 331, and the facing surface 386 has at least one groove 42 (example of a heat insulating structure 40). The at least one groove 42 consists of a central annular groove 421 and a plurality of straight grooves 422 extending from the annular groove 421 in the Z and Y directions, but the configuration of the groove 42 is not limited to this. Although not shown, a groove 42 may also be provided on the surface 3312 (see Figure 4) of the front plate 331 that faces the hopper flange 38.

[0039] This modified version also limits the transfer of heat from the hopper flange 38 to the front plate 331, thus achieving the same effects as the third embodiment. In this embodiment and this modified version, the retraction portion 313 is provided, but the reinforcing rib 315 in the first embodiment and the reinforcing portion 39A in the second embodiment can be omitted.

[0040] <Fourth Embodiment> Figure 11A shows a partially enlarged view of the injection cylinder 31, screw 32, and hopper flange 38 of the fourth embodiment. Similar to the first embodiment, the injection device 3 is equipped with a cooling water passage 61 through which cooling water flows to cool the hopper flange 38. In this embodiment, in addition to the above, there is a thermometer 63 for measuring the temperature of the hopper flange 38, a temperature adjustment means 64 provided in the cooling water passage 61, and a controller 65. The temperature adjustment means 64 includes an automatic on / off valve that automatically opens and closes according to the temperature measured by the thermometer 63. The controller 65 is connected to the thermometer 63 and the temperature adjustment means 64 and controls the opening and closing of the automatic on / off valve based on the temperature of the hopper flange 38 measured by the thermometer 63. The temperature adjustment means 64 is provided downstream of the throttle valve 62, but it can also be provided upstream of the throttle valve 62.

[0041] The automatic opening / closing valve of the temperature adjustment means 64 can be constituted by, for example, a solenoid valve. The solenoid valve opens when the temperature measured by the thermometer 63 is higher than a set value, and closes when the temperature is lower than the set value, but the opening / closing timing may be controlled by PID (Proportional-Integral-Differential) control or the like. Since a solenoid valve can only perform on-off control, that is, only fully open and fully closed, the flow rate of cooling water is adjusted by the throttle valve 62. However, when flow rate adjustment is not performed, the throttle valve 62 can be omitted.

[0042] The amount of heat transferred from the injection cylinder 31 to the hopper flange 38 is regulated by the drawing-in portion 313, so if cooling water is supplied at a constant flow rate, the hopper flange 38 and the hopper 5 may be supercooled. In the present embodiment, since the opening and closing of the automatic opening / closing valve is controlled based on the temperature of the hopper flange 38, it is easy to maintain the hopper flange 38 and the hopper 5 near the set temperature.

[0043] FIG. 11B is a partially enlarged view of an injection cylinder 31, a screw 32, and a hopper flange 38 according to a modification of the fourth embodiment. The configuration of the present modification is generally the same as that of the fourth embodiment, but in the present modification, the temperature adjustment means 64 includes a flow regulator that automatically controls the flow rate of cooling water according to the temperature measured by the thermometer 63. The controller 65 is connected to the thermometer 63 and the temperature adjustment means 64, and controls the flow rate of cooling water passing through the temperature adjustment means 64 based on the temperature of the hopper flange 38 measured by the thermometer.

[0044] Since the temperature adjustment means 64 of the fourth embodiment performs on-off control, there is a possibility that the temperature change of the hopper flange 38 becomes large immediately after the automatic opening / closing valve is opened or closed. However, in the present modification, the amount of cooling water can be adjusted by PID control or the like according to the difference between the set temperature and the actual temperature, so the temperature change rate and temperature change width of the hopper flange 38 can be suppressed, and it is easy to control the temperature of the hopper flange 38 more precisely. Although the drawing-in portion 313 is provided in the present embodiment and the present modification, the reinforcing rib 315 of the first embodiment and the reinforcing portion 39A of the second embodiment can be omitted.

[0045] <Fifth Embodiment> Figure 12 shows the hopper flange 38 of the fifth embodiment. The injection device 3 has a heating device 43 for heating the hopper flange 38. It is preferable that the injection material be maintained at a certain temperature so that it melts easily. As mentioned above, the amount of heat transmitted from the injection cylinder 31 to the hopper flange 38 is restricted by the draw-in section 313. For this reason, if the temperature of the injection material fed into the hopper 5 is low, the temperature of the injection material immediately after being supplied to the injection cylinder 31 may also remain low. By heating the hopper flange 38 with the heating device 43, the reduction in the amount of heat transmitted from the injection cylinder 31 to the hopper flange 38 can be compensated for, and the injection material can be preheated to a preferred temperature.

[0046] The heating device 43 can have any configuration as long as it can heat the hopper flange 38. As shown in Figure 12, the heating device 43 is a plate heater attached to the outer surface of the hopper flange 38, but a rod heater inserted into a hole formed in the hopper flange 38 can also be used. The installation location of the heating device 43 is not particularly limited, but in order to efficiently heat the injection material and suppress heat transfer to the front plate 331, it is preferable to install it in a position closer to the injection cylinder 31 than the front plate 331. In this embodiment, a retraction section 313 is provided, but the reinforcing rib 315 in the first embodiment and the reinforcing section 39A in the second embodiment can be omitted.

[0047] <Sixth Embodiment> Figure 13A shows a partially enlarged view of the injection cylinder 31, hopper flange 38, and hopper 5 of the sixth embodiment. The hopper 5 has a double-wall structure consisting of an inner wall 53 and an outer wall 54 separated from the inner wall 53. The inner wall 53 and the outer wall 54 can be formed from thin metal sheets. The upper part of the inner wall 53 is covered by a top plate 53A, and the outer wall 54 covers the entire inner wall 53. A sealed space 55 is formed between the inner wall 53 and the outer wall 54. The space 55 is filled with air, but it may be under reduced pressure or under vacuum. The space 55 may be filled with an insulating material such as glass wool.

[0048] The injection material supplied from the hopper 5 is dried in advance by a dryer 56. The internal space of the hopper 5 is brought to a negative pressure by a blower 57, and the dried injection material is supplied to the hopper 5 through a supply path 58. Although not illustrated, instead of bringing the internal space of the hopper 5 to a negative pressure by the blower 57, compressed air may be sent from a compressor to the supply path 58 to pressure-feed the dried injection material to the hopper 5.

[0049] The injection material is brought to a certain high-temperature state by the dryer 56, but since the hopper 5 is usually formed of a thin metal plate, the heat of the injection material may radiate from the hopper 5. When the injection material is cooled, the heat load on the heater 11 may increase. By forming the hopper 5 into a double-wall structure, the heat insulation performance of the hopper 5 is improved, which makes it easy to retain the heat of the injection material and maintain its dry state. The number of side walls of the hopper 5 is not limited to two, that is, the inner wall 53 and the outer wall 54, and the hopper 5 may be a multi-wall structure provided with two or more walls.

[0050] Fig. 13B is a partially enlarged view of an injection cylinder 31, a hopper flange 38, and a hopper 5 according to a modification of the sixth embodiment. The injection device 3 includes a heat insulating material 59 for the hopper 5 attached to the outer surface of the hopper 5. The heat insulating material 59 can be formed of bakelite or the like. This modification also achieves the same effects as those of the sixth embodiment. Note that although the lead-in portion 313 is provided in the present embodiment and the present modification, the reinforcing rib 315 of the first embodiment and the reinforcing portion 39A of the second embodiment can be omitted.

[0051] <Seventh Embodiment> Fig. 14A is a schematic front view of an injection device 3 according to a seventh embodiment, and Fig. 14B is a schematic cross-sectional view of the injection device 3 taken along line 14B-14B in Fig. 14A. In the present embodiment, a plurality of infrared heaters 13 are used instead of the heater 11 that covers the outer peripheral surface of the injection cylinder 31. The type of the infrared heater 13 is not limited. Heaters that heat an object by radiant heating can be used, including: Kanthal heaters using Kanthal (registered trademark), which is an alloy of iron, chromium, and aluminum, as a heating element; carbon heaters using carbon fiber as a heating element; halogen heaters using a halogen lamp as a heating element; and ceramic heaters using ceramic as a heating element.

[0052] In this embodiment, an infrared heater 13 is used, which has a heating element sealed inside a glass tube. The multiple infrared heaters 13 have an elongated shape in the X direction and are provided at a distance from the outer surface of the injection cylinder 31. The multiple infrared heaters 13 are arranged in the X direction and are provided around the injection cylinder 31 at approximately equal angular intervals when viewed from the X direction.

[0053] The injection device 3 includes a terminal (not shown) electrically connected to the infrared heater 13 and supplying power to the infrared heater 13, and a partition plate 14 that supports the infrared heater 13. The partition plate 14 is provided at both ends in the X direction of each infrared heater 13. Since the multiple infrared heaters 13 are partitioned in the X direction by the partition plate 14, the amount of heating of the injection cylinder 31 can be adjusted for each zone in the X direction.

[0054] A cylindrical reflector 15 is provided on the radially R-outside of the infrared heater 13, at a distance from the infrared heater 13. The reflector 15 can be made of a metal such as stainless steel. The reflector 15 reflects the infrared rays emitted from the infrared heater 13 and directs them into the injection cylinder 31, thus effectively utilizing the radiant heat of the infrared heater 13. An insulating material 16 made of glass wool or the like is provided on the radially R-outside of the reflector 15. The insulating material 16 suppresses the dissipation of radiant heat from the reflector 15 to the radially R-outside. A cylindrical cover 17 made of iron or the like is provided on the radially R-outside of the insulating material 16. The cover 17 protects the insulating material 16. The reflector 15 and the cover 17 also serve as a housing for the insulating material 16 and can be manufactured integrally with the insulating material 16. The reflector 15, the insulating material 16, and the cover 17 are divided circumferentially (divided into two parts in the illustrated example) for installation and removal.

[0055] When the heater 11 and heat-insulating material 12 are wrapped around the outer surface of the injection cylinder 31, as in the first to sixth embodiments, there are areas where the heater 11 cannot be tightly wrapped around the outer surface of the injection cylinder 31 due to terminals and other protruding parts from the outer surface of the injection cylinder 31. In addition, due to the limitations of the deformation properties of the heat-insulating material 12, gaps may form between the heater 11 and the heat-insulating material 12, causing heat loss. For these reasons, the heat-insulating performance may be reduced in a configuration using the heater 11 and heat-insulating material 12.

[0056] In contrast, in this embodiment, by enclosing the heat insulating material 16 within a housing structure consisting of a reflector 15 and a cover 17 so as to be in close contact with the reflector 15 and the cover 17, the heat insulating performance of the heat insulating material 16 around the heater 11 can be equalized, thereby improving heat retention. Furthermore, since the multiple infrared heaters 13 are evenly arranged circumferentially at a distance from the injection cylinder 31, the injection cylinder 31 can be heated more uniformly. Although not shown in the figures, the injection cylinder 31 can be rapidly cooled by supplying airflow to the gap between the multiple infrared heaters 13 and the injection cylinder 31. As a result, the temperature of the injection cylinder 31 can be controlled with greater precision, and the time required for setup to change the raw material resin can be reduced.

[0057] Although the present disclosure has been described above with respect to several embodiments, these embodiments can be implemented in combination with each other, and the way they are combined is not limited. For example, the reinforcing rib 315 of the first embodiment and the reinforcing part 39A of the second embodiment can be combined, and the first or second embodiment can be combined with at least one of the third to sixth embodiments (or modifications). Furthermore, the seventh embodiment can be combined with at least one of the first to sixth embodiments (or modifications) and will have the same effects as the first to sixth embodiments (or modifications).

[0058] While several preferred embodiments of the present invention have been described in detail, it should be understood that various changes and modifications are possible without departing from the spirit or scope of the appended claims.

[0059] 1 Injection molding machine 2 Clamping device 3 Injection device 5 Hopper 11 Heater 13 Infrared heater 31 Injection cylinder 32 Screw 38 Hopper flange 39A Reinforcement part 39B Welded part 41 Insulation plate 42 Groove 43 Heating device 61 Cooling water passage 63 Thermometer 64 Temperature adjustment means 312 Supply part 313 Retraction part 314A, 314B Adjacent part 315 Reinforcement rib 317 Space part 331 Front plate

Claims

1. An injection device comprising: an injection cylinder having a supply section for supplying injection material and a retraction section; and a heater for heating the injection cylinder, wherein both ends of the retraction section in the axial direction of the injection cylinder are located between the supply section and the heater, the retraction section is retracted radially inward from two adjacent sections adjacent to the retraction section, and the injection cylinder has reinforcing ribs, the reinforcing ribs are provided radially outward from the retraction section and continuously with the two adjacent sections and the retraction section.

2. The injection device according to claim 1, wherein the retraction portion has a cylindrical shape, and the radial distance between the outer circumferential surface of the retraction portion and the outer circumferential surfaces of the two adjacent portions is greater than the axial length of the retraction portion.

3. The injection device according to claim 1, wherein the retraction portion has a cylindrical shape, and the reinforcing rib extends radially from the retraction portion.

4. The injection device according to claim 2, wherein the retraction portion has a cylindrical shape, and the reinforcing rib extends vertically from the retraction portion.

5. The injection apparatus according to claim 1, comprising a hopper for supplying the injection material to the injection cylinder, and a hopper flange supporting the hopper and the injection cylinder, wherein both ends of the retraction portion are located between the hopper flange and the heater.

6. An injection device comprising: an injection cylinder having a supply section for supplying injection material and a retraction section; a heater for heating the injection cylinder; and a reinforcing section for the retraction section, wherein both ends of the retraction section in the axial direction of the injection cylinder are located between the supply section and the heater, the retraction section is retracted radially inward of the injection cylinder from two adjacent sections adjacent to the retraction section, and the reinforcing section is provided radially away from the retraction section and extends circumferentially of the injection cylinder.

7. The injection device according to claim 6, wherein the reinforcing portion extends around the entire circumference of the injection cylinder.

8. The injection device according to claim 7, wherein the reinforcing portion is an annular member having the same outer diameter as the two adjacent portions, and has a welded portion that fixes the reinforcing portion and the two adjacent portions.

9. The injection apparatus according to claim 7, comprising a hopper for supplying the injection material to the injection cylinder, and a hopper flange supporting the hopper and the injection cylinder, wherein the hopper flange covers the entire area of ​​the retraction portion, and the hopper flange is the reinforcing portion.

10. The injection apparatus according to claim 6, comprising a hopper for supplying the injection material to the injection cylinder, and a hopper flange supporting the hopper and the injection cylinder, wherein both ends of the retraction portion are located between the hopper flange and the heater.

11. An injection device comprising: an injection cylinder having a supply section for supplying injection material and a retraction section; a screw housed in the injection cylinder; a heater for heating the injection cylinder; a hopper for supplying the injection material to the injection cylinder; a hopper flange supporting the hopper and the injection cylinder; a front plate to which the hopper flange is fixed and which rotatably supports the screw; and a heat insulating structure for restricting heat transfer from the hopper flange to the front plate, wherein both ends of the retraction section in the axial direction of the injection cylinder are located between the supply section and the heater, and the retraction section is retracted radially inward from two adjacent sections adjacent to the retraction section.

12. The injection apparatus according to claim 11, wherein the heat insulating structure has a heat insulating plate located between the hopper flange and the front plate.

13. The injection apparatus according to claim 11, wherein the hopper flange has an opposing surface facing the front plate, the front plate has an opposing surface facing the hopper flange, and the heat insulating structure has a groove provided on either the opposing surface of the front plate or the opposing surface of the hopper flange.

14. An injection device comprising: an injection cylinder having a supply section for supplying injection material and a retraction section; a heater for heating the injection cylinder; a hopper for supplying the injection material to the injection cylinder; a hopper flange supporting the hopper and the injection cylinder; a cooling water passage through which cooling water flows for cooling the hopper flange; a thermometer for measuring the temperature of the hopper flange; and a temperature adjustment means provided in the cooling water passage for adjusting the temperature of the hopper flange according to the temperature measured by the thermometer, wherein both ends of the retraction section in the axial direction of the injection cylinder are located between the supply section and the heater, and the retraction section is retracted radially inward from two adjacent sections adjacent to the retraction section.

15. The injection device according to claim 14, wherein the temperature adjustment means includes a valve that automatically opens and closes in accordance with the temperature measured by the thermometer.

16. The injection device according to claim 14, wherein the temperature adjustment means automatically controls the flow rate of the cooling water according to the temperature measured by the thermometer.

17. An injection device comprising: an injection cylinder having a supply section for supplying injection material and a retraction section; a heater for heating the injection cylinder; a hopper for supplying the injection material to the injection cylinder; a hopper flange supporting the hopper and the injection cylinder; and a heating device for heating the hopper flange, wherein both ends of the retraction section in the axial direction of the injection cylinder are located between the supply section and the heater, and the retraction section is retracted radially inward from two adjacent sections adjacent to the retraction section.

18. An injection apparatus according to any one of claims 1 to 4, 6 to 8, comprising a hopper for supplying the injection material to the injection cylinder, wherein the hopper has a multi-wall structure including an inner wall and an outer wall separated from the inner wall.

19. The injection device according to claim 18, wherein a sealed space is formed between the inner wall and the outer wall.

20. An injection apparatus according to any one of claims 1 to 4, 6 to 8, comprising a hopper for supplying the injection material to the injection cylinder, and a heat insulating material for the hopper.

21. The injection device according to any one of claims 5, 9 to 17, wherein the hopper has a multi-wall structure including an inner wall and an outer wall separated from the inner wall.

22. The injection device according to claim 21, wherein a sealed space is formed between the inner wall and the outer wall.

23. The injection apparatus according to any one of claims 5, 9 to 17, further comprising a heat-insulating material for the hopper.

24. The injection apparatus according to any one of claims 1 to 17, wherein the heater is an infrared heater located away from the injection cylinder.

25. An injection molding machine having an injection device according to any one of claims 1 to 17, and a mold clamping device that supports a mold and opens and closes the mold.

Images