Injection device and injection molding machine equipped therewith

Abstract

In the injection device 3, the injection material is supplied stably while being sufficiently heated. [Solution] The injection device 3 includes an injection cylinder 31 having a supply section 312 for supplying injection material and a retraction section 313, and a heater 11 for heating the injection cylinder 31. Both ends of the retraction section 313 in the axial direction X of the injection cylinder 31 are between the supply section 312 and the heater 11, and the retraction section 313 is retracted radially inward from two adjacent sections adjacent to the retraction section 313. The injection cylinder 31 has reinforcing ribs 315, which are provided radially outward from the retraction section 313 and continuously with the two adjacent sections and the retraction section 313.

Description

[Technical Field]

[0001] The present disclosure relates to an injection device and an injection molding machine including the same. [Background Art]

[0002] Patent Document 1 describes an injection device for an injection molding machine. The injection device 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. [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2016-2696 [Summary of the Invention] [Problems to be Solved by the Invention]

[0004] 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.

[0005] An object of the present disclosure is to provide an injection device that enables stable supply of an injection material while sufficiently heating the injection material. [Means for Solving the Problems]

[0006] The injection device includes an injection cylinder having a supply section and a retraction section for supplying the injection material, and a heater for heating the injection cylinder. Both ends of the retraction section in the axial direction of the injection cylinder are located between the supply section and the heater. The injection cylinder has reinforcing ribs continuous with the retraction section, or reinforcing sections of the retraction section that are separated from the retraction section. [Effects of the Invention]

[0007] According to this disclosure, it is possible to provide an injection molding apparatus that enables a stable supply of injection material while sufficiently heating the injection material. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic front view of an injection molding machine according to the first embodiment. [Figure 2] Figure 1 is a schematic front view of the injection mechanism of the injection molding machine shown. [Figure 3] Figure 2 is a magnified view of a portion of the injection device shown. [Figure 4] Figure 2 is a partially exploded perspective view of the injection device. [Figure 5A] This is a magnified view of the entry point. [Figure 5B] Figure 5A is a cross-sectional view of the retraction section. [Figure 5C] This is a cross-sectional view of a modified example of the retraction section. [Figure 5D] This is a cross-sectional view of another modified example of the retraction section. [Figure 6A] This is an enlarged view of the retraction section of the injection device according to the second embodiment. [Figure 6B] Figure 6A is a cross-sectional view of the retraction section. [Figure 6C] This is a cross-sectional view of a modified example of the retraction section. [Figure 7A] This is an enlarged view of the retraction section of the injection device according to a modified example of the second embodiment. [Figure 7B] Figure 7A is a cross-sectional view of the retraction section. [Figure 8] This is a partially enlarged view of the injection device according to the third embodiment. [Figure 9] It is a partially exploded perspective view of the injection device shown in Fig. 8. [Figure 10] It is a plan view of a hopper flange of an injection device according to a modified example of the third embodiment. [Figure 11A] It is a partially enlarged view of an injection device according to the fourth embodiment. [Figure 11B] It is a partially enlarged view of an injection device according to a modified example of the fourth embodiment. [Figure 12] It is a perspective view of a hopper flange of an injection device according to the fifth embodiment. [Figure 13A] It is a partially enlarged view of an injection device according to the sixth embodiment. [Figure 13B] It is a partially enlarged view of an injection device according to a modified example of the sixth embodiment. [Figure 14A] It is a schematic front view of an injection device according to the seventh embodiment. [Figure 14B] It is a schematic cross-sectional view of an injection device according to the seventh embodiment. MODE FOR CARRYING OUT THE INVENTION

[0009] Hereinafter, several embodiments of the present disclosure will be described with reference to the drawings. The embodiments described below relate to a horizontal injection device for injecting resin and a horizontal injection molding machine including the same, but the present disclosure can also be applied to vertical injection devices and metal injection devices. In the following description and drawings, the axial direction of the injection cylinder and the screw is referred to as the X direction. The X direction is parallel to the horizontal direction. The direction from the injection device toward the mold clamping device, or the injection direction, is referred to as the +X direction, and the direction from the mold clamping device toward the injection device is referred to as the -X direction. A 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.

[0010] <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.

[0011] <Mold clamping device 2> As shown in Figure 1, the clamping device 2 comprises a fixed platen 22 fixed on the bed 21 to which a fixed mold M1 is attached, a clamping housing 24 that is slidable on the bed 21, and a movable platen 23 that is slidable on the bed 21 to which a movable mold M2 is attached. The fixed platen 22 and the clamping housing 24 are connected by a number of tie bars 25. A clamping mechanism 26 for opening and closing the mold is provided between the movable platen 23 and the clamping housing 24. The clamping mechanism 26 is composed of a toggle mechanism, but may also be composed of a hydraulic clamping injection cylinder.

[0012] <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 for mixing and plasticizing the injection material, a drive mechanism 33 for driving the screw 32, and a nozzle touch device 34 for driving 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.

[0013] <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.

[0014] The drive mechanism 33 is driven by a plasticizing motor 335 provided on the intermediate plate 332. The screw 32 is rotationally driven around the central axis 32C. 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 rotationally drives the ball screw 336 by an injection motor 338 provided on the rear plate 333, thereby driving the intermediate plate 332 and the screw 32 in the X direction.

[0015] <Heater 11 and insulation material 12> The injection device 3 has a heater 11 that covers the outer circumferential 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 also be a rod heater inserted into a hole formed in the injection cylinder 31. The injection device 3 has a heat-insulating material 12 that covers the outer circumferential surface of the heater 11. As the heat-insulating material 12, a cylinder protection material made of insulating material such as glass wool wrapped in a heat-resistant jacket can be used. The heat-insulating material 12 can also be omitted.

[0016] <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, while Figure 4 shows an exploded perspective view of a part of the injection cylinder 31, the hopper flange 38, and the 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 located 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 an upper opening 51 serving as the injection material input section and a lower opening 52 serving as the injection material discharge section.

[0017] 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 formed, for example, from 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 number 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.

[0018] As shown in Figures 3 and 4, the cylindrical portion 381 has a through hole 38 that communicates with the lower opening 52 of the hopper 5. 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 into 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.

[0019] 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.

[0020] <Thermal insulation structure of injection cylinder 31> Figure 5A is an enlarged view of section A in Figure 3, showing the vicinity of the retraction section 313. The heat-insulating 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, etc.

[0021] Both ends 313A and 313B of the lead-in portion 313 in the X direction are located between the supply portion 312 and the heater 11 (when a plurality of heaters 11 are provided in series in the X direction, the heater 11 closest to the supply portion 312), so the heat Q transferred through the injection cylinder 31 in the -X direction can be restricted by the supply portion 312. In the present embodiment, both ends 313A and 313B of the lead-in portion 313 in the X direction are located between the hopper flange 38 and the heater 11.

[0022] FIG. 5B is a cross-sectional view taken along line 5B-5B in FIG. 5A. The lead-in portion 313 is led inward in the radial direction R of the injection cylinder 31 relative to two adjacent portions 314A and 314B. The radial direction R is a direction toward or away from the center of the injection cylinder 31 when the injection cylinder 31 is viewed from the X direction, and coincides with the Z direction in FIGS. 2, 3 and 5A. The reinforcing rib 315 is provided outside the lead-in portion 313 in the radial direction R. The reinforcing rib 315 is provided continuously to the mutually opposing side surfaces 314C, 313D of the two adjacent portions 314A, 314B and the lead-in portion 313. The lead-in portion 313 and the reinforcing rib 315 can be formed, for example, by cutting a part of the injection cylinder 31.

[0023] Let S1 be the cross-sectional area of the cross-section of the lead-in portion 313 perpendicular to the X direction, S2 be the cross-sectional area of the cross-section of the reinforcing rib 315 perpendicular to the X direction (the total cross-sectional area when a plurality of reinforcing ribs 315 are provided), and S3 be the cross-sectional area of the cross-section of each of the adjacent portions 314A and 314B perpendicular to the X direction, then S1 < S3, and S1+S2 < S3. Therefore, the heat Q transferred from the adjacent portion 314A on the heater 11 side to the adjacent portion 314B on the supply portion 312 side is restricted. This suppresses the temperature rise of the supply portion 312, and reduces the possibility that the injection material supplied from the supply portion 312 softens or melts and blocks the supply portion 312.

[0024] As shown in Figure 5A, the radial distance D3 between the outer surface of the inlet portion 313 and the outer surfaces of the two adjacent portions 314A and 314B is greater than the axial length D4 of the inlet portion 313. In other words, the radial R dimension of the notch 316 is greater than the axial X dimension. This makes it possible to more effectively regulate the heat Q passing through the inlet portion 313, that is, the heat Q transmitted from the adjacent portion 314A on the heater 11 side to the adjacent portion 314B on the supply portion 312 side.

[0025] 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 section 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 section 313, the second moment of area can be effectively increased.

[0026] As shown in Figure 5B, multiple (five in this embodiment) reinforcing ribs 315 extend radially from the retraction section 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.

[0027] 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 are effective against bending moments in the Z direction, such as the moment of self-weight.

[0028] 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.

[0029] <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.

[0030] 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.

[0031] 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.

[0032] In this embodiment, the injection cylinder 31 has a sealed space 317 on the radially R-outward side 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.

[0033] 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.

[0034] <Modified form of the second embodiment> Figure 7A shows a partially enlarged view of the injection cylinder 31 and hopper flange 38 of a modified example 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 section 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 modified example, the hopper flange 38 functions as a reinforcing section 39A, so the reinforcing section 39A in Figure 6A can be omitted, and welding is not required. However, it is also possible to provide the reinforcing section 39A in Figure 6A, and it is also possible to provide the reinforcing rib 315 of the first embodiment.

[0035] <Third Embodiment> Figure 8 shows 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 shows 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.

[0036] 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.

[0037] 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 will continue 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.

[0038] 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 efficient use of the heat from the heater 11, leading to energy savings.

[0039] <Modified form 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 modified example of the third embodiment. The hopper flange 38 has a surface 386 (see Figure 4) facing the front plate 331, and the 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 facing the hopper flange 38.

[0040] This modified version also limits heat transfer from the hopper flange 38 to the front plate 331, thus achieving the same effect 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.

[0041] <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 this, 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.

[0042] The automatic on / off valve of the temperature control means 64 can be configured as, for example, a solenoid valve. The solenoid valve closes when the temperature measured by the thermometer 63 is higher than the set value and opens when it is lower than the set value, but the timing of opening and closing may be controlled by PID (Proportional-Integral-Differential) control or the like. Since the solenoid valve can only be controlled on or off, i.e., fully open and fully closed, the flow rate of the cooling water is adjusted by the throttle valve 62, but if flow rate adjustment is not required, the throttle valve 62 can be omitted.

[0043] Since the amount of heat transferred from the injection cylinder 31 to the hopper flange 38 is restricted by the intake section 313, supplying cooling water at a constant flow rate may cause the hopper flange 38 and hopper 5 to be overcooled. In this embodiment, the opening and closing of the automatic on / off valve is controlled based on the temperature of the hopper flange 38, making it easy to maintain the hopper flange 38 and hopper 5 near the set temperature.

[0044] Figure 11B shows a partially enlarged view of the injection cylinder 31, screw 32, and hopper flange 38 of a modified example of the fourth embodiment. The configuration of this modified example is generally the same as that of the fourth embodiment, except that the temperature control means 64 includes a flow regulator that automatically controls the flow rate of the cooling water according to the temperature measured by the thermometer 63. The controller 65 is connected to the thermometer 63 and the temperature control means 64 and controls the flow rate of the cooling water passing through the temperature control means 64 based on the temperature of the hopper flange 38 measured by the thermometer.

[0045] In the fourth embodiment, the temperature control means 64 performs on / off control, which may cause a large temperature change in the hopper flange 38 immediately after the automatic opening or closing of the valve. However, in this modified example, 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, making it easier to suppress the rate and width of temperature change in the hopper flange 38 and to control the temperature of the hopper flange more precisely. In this embodiment and this modified example, the pull-in 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.

[0046] <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. Therefore, 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.

[0047] 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.

[0048] <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 may be under reduced pressure or under vacuum. The space 55 may be filled with an insulating material such as glass wool.

[0049] The injection material supplied from the hopper 5 is dried beforehand by the dryer 56. The internal space of the hopper 5 is made negatively pressurized by the blower 57, and the dried injection material is supplied to the hopper 5 through the supply passage 58. Although not shown in the figure, instead of making the internal space of the hopper 5 negatively pressurized by the blower 57, compressed air may be sent from a compressor to the supply passage 58, and the dried injection material may be pressurized and sent to the hopper 5.

[0050] Although the injection material is brought to a certain high temperature by the dryer 56, the hopper 5 is usually made of thin metal sheets, so there is a possibility that heat from the injection material may be dissipated from the hopper 5. If the injection material cools down, the heat load on the heater 11 may increase. By making the hopper 5 a double-wall structure, the thermal insulation of the hopper 5 is improved, making it easier to retain the heat of the injection material and maintain a dry state. The number of side walls of the hopper 5 is not limited to two, an inner wall 53 and an outer wall 54, but can be a multi-wall structure with two or more walls.

[0051] Figure 13B shows a partially enlarged view of the injection cylinder 31, hopper flange 38, and hopper 5 of a modified version of the sixth embodiment. The injection device 3 has a heat insulating material 59 attached to the outer surface of the hopper 5. The heat insulating material 59 can be made of bakelite or the like. This modified version also provides the same effects as the sixth embodiment. In this embodiment and this modified version, a retraction section 313 is provided, but the reinforcing rib 315 of the first embodiment and the reinforcing section 39A of the second embodiment can be omitted.

[0052] <Seventh Embodiment> Figure 14A shows a schematic front view of the injection device 3 of the seventh embodiment, and Figure 14B shows a schematic cross-sectional view of the injection device 3 along the line 14B-14B in Figure 14A. In this embodiment, instead of the heater 11 covering the outer surface of the injection cylinder 31, multiple infrared heaters 13 are used. The type of infrared heater 13 is not limited, and heaters that heat the target object by radiant heating can be used, such as Kanthal heaters using Kanthal (registered trademark), an alloy of iron, chromium, and aluminum, as the heating element, carbon heaters using carbon fiber as the heating element, halogen heaters using halogen lamps as the heating element, and ceramic heaters using ceramics as the heating element.

[0053] 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 a shape that is elongated in the X direction and are provided at a position away 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.

[0054] 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.

[0055] 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 as a single unit together with the insulating material 16. The reflector 15, insulating material 16, and cover 17 are divided circumferentially (divided into two parts in the illustrated example) for installation and removal.

[0056] 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 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.

[0057] 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. In addition, 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.

[0058] Although this 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). [Explanation of Symbols]

[0059] 1 injection molding machine 2 Mold clamping device 3 Injection device 5 Hoppers 11 Heater 13 Infrared Heater 31 Injection Cylinder 32 Screw 38 Hopper flange 39A Reinforcement part 39B Weld 41 Insulation board 42 Groove 43 Heating device 61 Cooling water channel 63 Thermometer 64 Temperature adjustment means 312 Supply section 313 Entrance 314A, 314B adjacent section 315 Reinforcement Rib 317 Space section 331 Front Plate

Claims

1. An injection cylinder having a supply section for supplying injection material and a retraction section, The injection cylinder has a heater for heating the injection cylinder, The ends of the retraction portion in the axial direction of the injection cylinder are located between the supply portion and the heater, and the retraction portion is retracted radially inward from two adjacent portions adjacent to the retraction portion. The injection device wherein the injection cylinder has reinforcing ribs, the reinforcing ribs are provided radially outward from the retraction portion and are continuous with the two adjacent portions and the retraction portion.

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. A hopper that supplies the injection material to the injection cylinder, The hopper and the injection cylinder are supported by a hopper flange, The injection apparatus according to claim 1, wherein both ends of the retraction portion are located between the hopper flange and the heater.

6. An injection cylinder having a supply section for supplying injection material and a retraction section, A heater for heating the injection cylinder, The reinforcing portion of the aforementioned retraction section is included, The ends of the retraction portion in the axial direction of the injection cylinder are located between the supply portion and the heater, and the retraction portion is retracted radially inward from two adjacent portions adjacent to the retraction portion. An injection device wherein the reinforcing portion is provided apart from the retracting portion in the radial direction and extends in the circumferential direction 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 reinforcing portion is an annular member having the same outer diameter as the two adjacent portions. The injection apparatus according to claim 7, further comprising a welded portion that fixes the reinforcing portion and the two adjacent portions.

9. A hopper that supplies the injection material to the injection cylinder, The hopper and the injection cylinder are supported by a hopper flange, The injection device according to claim 7, wherein the hopper flange covers the entire area of ​​the retraction portion, and the hopper flange is the reinforcing portion.

10. A hopper that supplies the injection material to the injection cylinder, The hopper and the injection cylinder are supported by a hopper flange, The injection apparatus according to claim 6, wherein both ends of the retraction portion are located between the hopper flange and the heater.

11. An injection cylinder having a supply section for supplying injection material and a retraction section, The screw housed in the injection cylinder, A heater for heating the injection cylinder, A hopper that supplies the injection material to the injection cylinder, A hopper flange supporting the hopper and the injection cylinder, The hopper flange is fixed to a front plate that rotatably supports the screw, It has an insulating structure that restricts heat transfer from the hopper flange to the front plate, An injection device in which both ends of the retraction portion in the axial direction of the injection cylinder are located between the supply portion and the heater, and the retraction portion is retracted radially inward of the injection cylinder from two adjacent portions adjacent to the retraction portion.

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 cylinder having a supply section for supplying injection material and a retraction section, A heater for heating the injection cylinder, A hopper that supplies the injection material to the injection cylinder, A hopper flange supporting the hopper and the injection cylinder, A cooling water channel through which cooling water flows to cool the hopper flange, A thermometer for measuring the temperature of the hopper flange, The cooling water flow path is provided with a temperature adjustment means that adjusts the temperature of the hopper flange according to the temperature measured by the thermometer, An injection device in which both ends of the retraction portion in the axial direction of the injection cylinder are located between the supply portion and the heater, and the retraction portion is retracted radially inward of the injection cylinder from two adjacent portions adjacent to the retraction portion.

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

16. The injection apparatus 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 cylinder having a supply section for supplying injection material and a retraction section, A heater for heating the injection cylinder, A hopper that supplies the injection material to the injection cylinder, A hopper flange supporting the hopper and the injection cylinder, The hopper flange has a heating device for heating the hopper flange, An injection device in which both ends of the retraction portion in the axial direction of the injection cylinder are located between the supply portion and the heater, and the retraction portion is retracted radially inward of the injection cylinder from two adjacent portions adjacent to the retraction portion.

18. The system includes a hopper that supplies the injection material to the injection cylinder, The injection device according to any one of claims 1 to 4, 6 to 8, wherein the hopper has a multi-wall structure including an inner wall and an outer wall separated from the inner wall.

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

20. A hopper that supplies the injection material to the injection cylinder, An injection apparatus according to any one of claims 1 to 4, 6 to 8, comprising the hopper insulation material.

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 apparatus 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 device according to any one of claims 1 to 17, and a device for supporting a mold and opening and closing the mold. An injection molding machine having a clamping device for performing the operation.

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