Injection molding machine

Abstract

To provide an injection molding machine that can stably control the stoppage of plasticized molding material.SOLUTION: An injection molding machine 1 has a hollow barrel 2 extending in one direction, a nozzle 3 provided at one end of the barrel 2 in one direction to inject the plasticized molding material in the barrel 2, an extrusion section 6 to push the molding material supplied inside the barrel 2 toward the nozzle 3, and a rod 8 extending in one direction through the extrusion section 6, a head 9 provided at the nozzle 3 side end of the rod 8, an internal heating portion 18 provided inside the rod 8 and extending in one direction, and a groove 41 formed on a surface along one direction and extending axially into the head 9 along one direction while in contact with the internal heating portion 19, and the heat transfer member 23 has a higher coefficient of thermal expansion than the head 9.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an injection molding machine. [Background technology]

[0002] For example, some parts of automobiles and the like are molded by injecting molding material such as resin raw material using an injection molding machine.

[0003] Patent Document 1 discloses that heat is transferred from a heat source to an injection section for injecting a molding material, while Patent Document 2 discloses that heat is transferred from a heat source to a tip of a torpedo. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2022-79145 [Patent Document 2] JP 2008-143157 A Summary of the Invention [Problem to be solved by the invention]

[0005] Here, in an injection molding machine, the molding material is plasticized inside and injected, but the fluidity of the plasticized molding material decreases in the area where the temperature of the plasticized molding material decreases, and the plasticized molding material may stagnate. If the plasticized molding material stagnates, thermal degradation may be accelerated, and adhesion or the like may occur, which may affect the molded product. For example, it is thought that the temperature drop of the plasticized molding material can be suppressed by the methods of Patent Document 1 and Patent Document 2, but it is desired to transfer heat more stably to the area where the temperature of the plasticized molding material is likely to drop.

[0006] In view of the above problems, an object of the present invention is to provide an injection molding machine that can stably suppress retention of plasticized molding material. [Means for solving the problem]

[0007] In order to solve the above problems, the injection molding machine of the present invention comprises a hollow barrel extending in one direction, a nozzle provided at one end side of the barrel in the one direction and for injecting molding material plasticized inside the barrel, an extrusion section that extrudes the molding material supplied inside the barrel toward the nozzle side, a rod extending in the one direction through the extrusion section, a head provided at an end of the rod on the nozzle side, an internal heating section provided inside the rod and extending in the one direction, and a heat transfer member that extends along the one direction while in contact with the internal heating section to the inside of the head, and has a groove extending in the one direction formed on its surface along the one direction, and has a thermal expansion coefficient higher than that of the head.

[0008] In addition, in the heat transfer member, the groove extends in the one direction in a spiral shape on the surface of the heat transfer member extending in the one direction.

[0009] The heat transfer member has a cylindrical shape that is elongated along the one direction, and has a plurality of the grooves formed at equal intervals in the circumferential direction.

[0010] In addition, in a cross section perpendicular to the direction in which the heat transfer member extends, the groove has a shape in which the two wall surfaces constituting the groove are in contact with each other on the central axis side of the heat transfer member, and the distance between the two wall surfaces increases radially outward.

[0011] The heat transfer member has a higher thermal conductivity than the head. Effect of the Invention

[0012] According to the injection molding machine of the present invention, retention of plasticized molding material can be stably suppressed. [Brief description of the drawings]

[0013] [Figure 1]1 is a diagram illustrating a schematic configuration of an injection molding machine according to an embodiment of the present invention. [Diagram 2] 2 is an enlarged cross-sectional view of the injection molding machine of FIG. 1, showing the periphery of the head. [Diagram 3] 2 is a diagram showing an example of a configuration of a heat transfer member in the injection molding machine of FIG. 1. [Figure 4] 4 is a diagram showing an example of a cross section perpendicular to the axial direction of the heat transfer member of FIG. 3. [Diagram 5] FIG. 2 is a diagram showing an example of a first step of injection molding using the injection molding machine of FIG. [Figure 6] 3 is a diagram showing an example of a second step of injection molding using the injection molding machine of FIG. 1. FIG. [Figure 7] 3 is a diagram showing an example of a third step of injection molding using the injection molding machine of FIG. 1. FIG. [Figure 8] 1. FIG. 4 is a diagram showing an example of a fourth step of injection molding using the injection molding machine of FIG. [Figure 9] 1. FIG. 4 is a diagram showing an example of a fifth step of injection molding using the injection molding machine of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In order to facilitate understanding of the description, the same reference numerals are used to designate the same components in each drawing, and duplicated description will be omitted as appropriate.

[0015] === Implementation form === <Overall composition> Fig. 1 is a diagram showing a schematic configuration of an injection molding machine 1 according to a first embodiment. In Fig. 1, a rod 8, a head 9, and a non-return ring 10, which will be described later, are shown as cross sections only on one side (the side on which a material supply unit 11 is provided) with respect to a central axis X of a barrel 2, and the other side with respect to the central axis X is shown as a side surface.

[0016] 1, an injection molding machine 1 plasticizes a molding material, such as a resin raw material, inside the machine and injects the plasticized resin raw material to the outside of a mold or the like. The injection molding machine 1 mainly includes a barrel 2, a nozzle 3, a heater 4, a plunger 6, a rod 8, a head 9, a check ring 10, and a material supply unit 11. For example, when a fluororesin is used as the resin raw material, each member that comes into contact with the resin raw material is made of an Invar material or the like that is resistant to corrosion by the fluororesin.

[0017] The barrel 2 has a cylindrical shape. The barrel 2 extends in one direction and is hollow. The axial direction of the barrel 2 along that direction is referred to as the "axial direction A". A nozzle 3 is provided at one end of the barrel 2 in the axial direction A. The end of the barrel 2 where the nozzle 3 in the axial direction A is provided (the injection side of the resin raw material) is referred to as the "downstream side", and the other end of the barrel 2 opposite to the end where the nozzle 3 in the axial direction A is provided (the supply side of the resin raw material) is referred to as the "upstream side".

[0018] The barrel 2 has, for example, a large diameter section 20 to which the resin raw material is supplied, and a small diameter section 22 located downstream of the large diameter section 20 and having a smaller outer diameter than the large diameter section 20.

[0019] The nozzle 3 is provided at one end of the barrel 2 in the axial direction A. Specifically, it is provided at the end of the barrel 2 on the downstream side in the axial direction A. The nozzle 3 has a nozzle hole 3a, and injects a plasticized resin raw material from the nozzle hole 3a toward the outside of a mold or the like. In FIG. 1, the nozzle 3 is shown as an open nozzle in which the nozzle hole 3a is open, but the nozzle 3 may be a shut-off nozzle having a valve capable of opening and closing the nozzle hole 3a.

[0020] The heater 4 is provided on the outer peripheral surface 2a of the barrel 2. The heater 4 is a heating section that heats the barrel 2 from the outside and heats the resin raw material inside the barrel 2 via the barrel 2. The heater 4 has a first heater section 4a provided for the large diameter section 20 of the barrel 2, a second heater section 4b provided for the small diameter section 22 of the barrel 2, and a nozzle heater section 4c provided for the nozzle 3.

[0021] The inner peripheral surface 2b of the barrel 2 has a tapered surface 20b inclined with respect to the axial direction A and a parallel surface 22b approximately parallel to the axial direction A in a range facing the portion of the outer peripheral surface 2a of the barrel 2 where the heater 4 is provided. The tapered surface 20b is formed so that the inner diameter becomes narrower from the upstream side to the downstream side. The tapered surface 20b is formed in a range of the inner peripheral surface 2b of the barrel 2 facing the portion of the outer peripheral surface 2a of the barrel 2 where the first heater section 4a is provided, that is, at the position of the large diameter section 20. The range in which the tapered surface 20b is formed is a position on the inner peripheral surface 2b of the barrel 2 that is downstream of the movable range of the plunger 6 and upstream of the movable range of the torpedo 16 (between the movable range of the plunger 6 and the movable range of the torpedo 16).

[0022] The parallel surface 22b is located downstream of the tapered surface 20b in the axial direction A, and is formed to have approximately the same inner diameter along the axial direction A. The parallel surface 22b is formed in a range of the inner circumferential surface 2b of the barrel 2 that faces a portion of the outer circumferential surface 2a of the barrel 2 where the second heater portion 4b is provided, that is, at the position of the small diameter portion 22. For example, the length of the parallel surface 22b in the axial direction A is longer than the length of the tapered surface 20b in the axial direction A.

[0023] The plunger 6 is an extrusion part that extrudes the resin raw material supplied inside the barrel 2 to the downstream side inside the barrel 2. The plunger 6 is provided so as to fit into an opening 2c formed at the upstream end of the barrel 2. A through hole 6c through which the rod 8 passes is formed in the center of the plunger 6. That is, the plunger 6 is hollow. The plunger 6 is a linear-acting extrusion part that moves along the axial direction A. The plunger 6 is connected to an actuator (not shown) via a predetermined fixing member 7a, for example, and moves in the axial direction A by the actuator without rotating. The plunger 6 may move (link) with the movement of the rod 8 by being fixed to the rod 8.

[0024] The rod 8 is provided inside the barrel 2 and extends in the axial direction A. The rod 8 is movable in the axial direction A. The rod 8 is disposed inside the barrel 2, for example, in a state in which it passes through the through hole 6c of the plunger 6 (inserted into the plunger 6), and extends in the axial direction A of the barrel 2. The rod 8 is connected to an actuator (not shown) via a predetermined fixing member 7b, for example, and is moved in the axial direction A by the actuator.

[0025] The rod 8 is provided with a torpedo 16. The torpedo 16 is formed on the downstream side of the rod 8, between the head 9 and the plunger 6. The torpedo 16 is formed integrally with the rod 8. Note that the torpedo 16 may be formed separately from the rod 8 and fixed to the rod 8. The torpedo 16 moves integrally with the rod 8 inside the barrel 2 along the axial direction A via the movement of the rod 8.

[0026] Torpedo 16 has a tapered portion that narrows from the downstream side to the upstream side. That is, torpedo 16 has tapered surface 16a, which is a tapered outer circumferential surface formed so that the outer diameter narrows from the downstream side to the upstream side. In addition, torpedo 16 has an outer diameter at downstream end 16b that has a gear shape, and end 16b has a large number of fins formed as protrusions.

[0027] The rod 8 also has an internal heater 18. The internal heater 18 is an internal heating section that heats the rod 8 from the inside. The internal heater 18 extends along the axial direction A toward the head 9 at the position of the central axis X of the rod 8. The internal heater 18 extends downstream from an upstream end connected to a power source (not shown), and extends, for example, into the torpedo 16, and heats the torpedo 16 from the inside. As a result, the internal heater 18 heats the resin raw material supplied into the barrel 2 via the torpedo 16. For example, the internal heater 18 reaches a temperature of about 200°C.

[0028] The head 9 is provided at the end of the rod 8 on the downstream side, that is, the nozzle 3 side. The head 9 is also called a stopper. The head 9 faces the nozzle 3 in the axial direction A. The head 9 extends in the axial direction A, and the end 9a on the nozzle 3 side has a gear-shaped outer periphery. That is, the end 9a of the head 9 on the nozzle 3 side has a larger outer diameter than the head 9 side, and a plurality of protrusions (fins) are formed on the end 9a in a direction perpendicular to the central axis.

[0029] The head 9 is fixed to the rod 8. For example, the head 9 and the rod 8 are attached and fixed by engaging threads provided on each of them. However, the fixing method is not limited.

[0030] FIG. 2 is an enlarged view of the head 9 in a cross section of the injection molding machine 1. The head 9 is provided with a heat transfer member 23. The heat transfer member 23 is, for example, cylindrical. The heat transfer member 23 is made of a material having a higher thermal conductivity than the head 9. The heat transfer member 23 extends in the axial direction A inside the head 9 while contacting the internal heater 18 of the rod 8. Specifically, one end of the heat transfer member 23 contacts the internal heater 18 of the rod 8, extends in the axial direction A to the inside of the head 9, and the other end does not penetrate the head 9 and is not exposed from the head 9. Therefore, the heat transfer member 23 releases the heat on the rod 8 side, i.e., the heat of the internal heater 18, to the head 9 by contact heat transfer. This provides heat to the head 9. For example, when the head 9 is made of an Invar material, it is difficult for heat to be transferred from other members because the thermal conductivity is not high, but by providing the heat transfer member 23 inside the head 9, heat can be effectively provided to the head 9.

[0031] For example, by attaching the heat transfer member 23 to the head 9 and then to the rod 8, the head 9 can be fixed to the rod 8 and the heat transfer member 23 can be brought into contact with the internal heater 18. In other words, providing the heat transfer member 23 on the head 9 side improves the ease of assembly and facilitates replacement, etc.

[0032] Returning to Fig. 1, the non-return ring 10 is provided between the torpedo 16 and the head 9 and can freely move between them. The non-return ring 10 is provided so as to surround a part of the head 9. The non-return ring 10 prevents the resin stored on the nozzle 3 side from flowing back upstream in the injection process described below.

[0033] The material supply section 11 is a section that supplies material to the inside of the barrel 2, and includes a hopper 30, a cylinder 32, a screw , and a preheater .

[0034] The hopper 30 stores the pellet-like (granular) resin raw material before plasticization, and supplies the resin raw material into the cylinder 32. The cylinder 32 is provided between a supply port 30a of the hopper 30 and a supply port 2d of the barrel 2.

[0035] The screw 34 is provided in the cylinder 32 and can be rotated by a material supply motor (not shown). By the rotation of the screw 34, the resin raw material charged in the cylinder 32 is supplied into the barrel 2 while rotating. The preheater 36 is provided on the outer peripheral surface 32a of the cylinder 32 and is a heating section that heats the resin raw material in the cylinder 32. Since the resin raw material is heated while being stirred, it is preheated with a high heat transfer effect.

[0036] <Configuration of heat transfer member 23> 3 is a diagram showing an example of the configuration of the heat transfer member 23. The heat transfer member 23 is made of a material having a higher thermal conductivity than the head 9, and further, is made of a material having a higher thermal expansion coefficient than the head 9. For example, the heat transfer member 23 is made of copper or tungsten.

[0037] Moreover, the heat transfer member 23 is a heat transfer rod having a cylindrical shape elongated along the axial direction A. The heat transfer member 23 has a groove 41 provided on its surface along the axial direction A. The groove 41 is a recess (slit) extending in the axial direction A on the surface of the heat transfer member 23 along the axial direction A. Specifically, the groove 41 extends in a spiral shape in the axial direction A on the surface of the heat transfer member 23. A spiral is a curve formed by a trajectory when the member moves in a direction perpendicular to the plane of rotation while rotating. That is, the groove 41 extends in both the axial direction A and the circumferential direction on the surface of the heat transfer member 23.

[0038] Further, a plurality of grooves 41 are formed at equal intervals in the circumferential direction of the heat transfer member 23. Fig. 2 illustrates a case in which four grooves 41 are formed at 90 degrees intervals in the circumferential direction. The number of grooves 41 is not limited to four and can be set as appropriate.

[0039] FIG. 4 is a diagram showing an example of a cross-sectional view of the heat transfer member 23. FIG. 4 shows a cross-section perpendicular to the direction in which the heat transfer member 23 extends (axial direction A). The groove 41 is formed in a triangular shape in the cross-section. That is, the groove 41 has a shape in which the two wall surfaces 42a and 42b constituting the groove 41 are in contact with each other at a connection point 43 on the central axis side of the heat transfer member 23 in the cross-section, and the distance between the two wall surfaces 42a and 42b increases toward the outside in the radial direction. In this way, the two wall surfaces 42a and 42b constituting the groove 41 form a V-shape.

[0040] <Injection molding process> Next, the steps of injection molding of a resin raw material using the injection molding machine 1 will be described with reference to Figures 5 to 9. Figures 5 to 9 are schematic cross-sectional views of the injection molding machine 1 in Figure 1, and are conceptual diagrams showing each step of injection molding using the injection molding machine 1. Although not shown, it is assumed that a mold for injecting a plasticized resin raw material is actually attached to the nozzle 3.

[0041] (1st process: material supply process) Fig. 5 is a conceptual diagram showing the first step of injection molding using the injection molding machine 1 of Fig. 1. In the first step (material supply step), a predetermined amount of pellet-shaped resin raw material R is supplied from the supply port 2d of the barrel 2 to between the plunger 6 and the torpedo 16 by the material supply unit 11. The plunger 6 is located upstream of the barrel 2 in the axial direction A, and the supply port 2d of the barrel 2 is in an open state. Then, the process proceeds to the second step.

[0042] (2nd process: 1st plasticization process) Fig. 6 is a conceptual diagram showing the second step of injection molding using the injection molding machine 1 of Fig. 1. In the second step (first plasticization step), the plunger 6 is moved from the upstream side to the downstream side, and the supply port 2d of the barrel 2 is closed by the plunger 6. Note that back pressure is applied to the rod 8. Also, the resin raw material R is brought into contact with the tapered surface 20b by the pressing force of the plunger 6 and heated, thereby plasticizing the pellet-shaped resin raw material R. Then, the process proceeds to the third step.

[0043] (3rd step: 2nd plasticization step) FIG. 7 is a conceptual diagram showing the third step of injection molding using the injection molding machine 1 of FIG. 1. In the third step (second plasticization step), the plunger 6 keeps the supply port 2d of the barrel 2 closed. The resin raw material R pushed in by the plunger 6 comes into contact with not only the tapered surface 20b of the barrel 2 but also the tapered surface 16a of the torpedo 16. The tapered surface 16a is heated by the second heater section 4b and the internal heater 18 and has a higher temperature, so the resin raw material R comes into contact with the tapered surface 16a and is plasticized. Then, the resin raw material R passes through the gap between the end 16b of the torpedo 16 and the inner peripheral surface 2b of the barrel 2 in the direction of the arrow B, and then passes through the gap between the non-return ring 10 and the head 9 to move downstream of the head 9, i.e., toward the nozzle 3 side of the barrel 2. Since heat is transferred from the internal heater 18 to the head 9 by the heat transfer member 23, a decrease in the temperature of the resin raw material R is suppressed when the resin raw material R moves from the upstream side to the downstream side of the head 9, and the resin raw material R is suppressed from accumulating around the head 9. Then, the resin J that has been plasticized and is ready for molding is accumulated in the tip portion of the barrel 2 on the nozzle 3 side. The torpedo 16 is pushed up to the upstream side by the internal pressure of this accumulated resin J. Then, the process proceeds to the fourth step.

[0044] (4th process: Weighing process) Figure 8 is a conceptual diagram showing the fourth step of injection molding using the injection molding machine 1 of Figure 1. In the fourth step (measurement step), the position of the torpedo 16 is controlled so that the amount of resin J, which is the plasticized resin raw material R accumulated on the nozzle 3 side of the head 9, becomes a set amount. The position of the torpedo 16 is stopped at a position where the set amount of resin J required for injection molding has accumulated. In addition, the plunger 6 is moved upstream to the raised end to suck back the rod 8. By sucking back, the internal pressure of the resin J is reduced. Then, the process proceeds to the fifth step.

[0045] (5th process: injection process) Fig. 9 is a conceptual diagram showing a fifth step of injection molding using the injection molding machine 1 of Fig. 1. In the fifth step (injection step), the rod 8 is moved downstream, and the resin J stored on the nozzle 3 side is injected toward the mold from the nozzle hole 3a of the nozzle 3. Then, a holding pressure is applied to hold the resin J filled in the mold so that it does not flow back into the injection molding machine 1.

[0046] After the fifth step, for example, the process proceeds to a cooling step of the resin J filled in the mold, and after the cooling is completed, the mold is opened and the molded product is removed, completing one molded product. In addition, in parallel with this cooling step, the process returns to the first step, and the first to fifth steps are repeated, so that molded products can be produced continuously. Note that the first step may be performed between the fourth and fifth steps, and after the fifth step, the first step may be omitted and the process proceeds to the second step. That is, after the plasticization and measurement step of the resin raw material R, the plunger 6 may be moved to open the supply port 2d of the barrel 2, and the material for the next injection molding may be supplied from the supply port 2d before proceeding to the injection step, and after the injection step, the process may proceed directly to the next plasticization step.

[0047] <Action and effect> As described above, in this embodiment, since the heat transfer member 23 extends in the axial direction A inside the head 9 while contacting the internal heater 18, the heat of the internal heater 18 can be transferred to the head 9. This is particularly effective when the head 9 is made of an Invar material having a low thermal conductivity. Furthermore, since the heat transfer member 23 is made of a material having a higher thermal expansion coefficient than the head 9, the heat transfer member 23 is less likely to contract relative to the head 9 even in an environment where the temperature drops and the member is likely to contract, and the head 9 and the heat transfer member 23 can be stably contacted. That is, the heat transfer member 23 is prevented from contracting and becoming out of contact with the head 9, and heat can be stably transferred from the heat transfer member 23 to the head 9. Furthermore, the internal heater 18 and the heat transfer member 23 can be stably contacted. Furthermore, since the groove 41 is formed in the surface (outer periphery) of the heat transfer member 23 in the axial direction A, the groove 41 is crushed in the circumferential direction due to thermal expansion, and the thermal expansion of the heat transfer member 23 in the radial direction is suppressed. This suppresses the heat transfer member 23 from pressing the head 9. For example, when the head 9 is made of an Invar material, the head 9 is unlikely to expand thermally, and therefore the groove 41 effectively prevents the heat transfer member 23 from pressing the head 9. In other words, the contact state between the head 9 and the heat transfer member 23 can be maintained well against thermal expansion. In this way, the heat transfer member 23 is provided on the head 9, and the heat transfer member 23 has a higher thermal expansion coefficient than the head 9, and the grooves 41 are formed in the surface (outer periphery) in the axial direction A, so that heat can be stably applied to the head 9 by the heat transfer member 23. This makes it possible to stably prevent the temperature of the head 9 from decreasing and the plasticized resin raw material from accumulating around the head 9. Since the accumulation of the plasticized resin raw material is suppressed, for example, it is possible to prevent the resin raw material from accumulating and solidifying, which may cause contamination.

[0048] In addition, one end of the heat transfer member 23 contacts the internal heater 18 inside the rod 8, and the other end does not penetrate the head 9, so that the heat of the heat transfer member 23 is prevented from escaping to anywhere other than the head 9, and heat can be efficiently transferred to the head 9.

[0049] Furthermore, the grooves 41 of the heat transfer member 23 are formed in a spiral shape on the surface of the extending heat transfer member 23, and therefore the grooves 41 are formed in the circumferential direction on the surface of the heat transfer member 23, so that the grooves 41 collapse in the axial direction A due to thermal expansion, suppressing the thermal expansion of the heat transfer member 23 in the axial direction A. This suppresses excessive deformation of the heat transfer member 23. In particular, by forming the grooves 41 in a spiral shape, it is possible to suppress the thermal expansion of the heat transfer member 23 in both the radial direction and the axial direction A.

[0050] Furthermore, by forming a plurality of grooves 41 at equal intervals in the circumferential direction in the heat transfer member 23, the thermal expansion of the heat transfer member 23 can be absorbed approximately uniformly in the circumferential direction.

[0051] In addition, since the grooves 41 in the heat transfer member 23 are triangular, when the heat transfer member 23 thermally expands, force is concentrated at the corners (connection points 43) of the grooves 41, so that the grooves 41 are more likely to collapse in the circumferential direction than when the grooves 41 are formed in a rectangular shape, for example. This makes it possible to effectively absorb the thermal expansion of the heat transfer member 23.

[0052] Furthermore, since the heat transfer member 23 has a higher thermal conductivity than the head 9 , the heat transferred from the internal heater 18 to the heat transfer member 23 can be effectively dissipated to the head 9 .

[0053] <<Variations>> The present invention is not limited to the above-described embodiment. In other words, the above-described specific example may be modified by a person skilled in the art as appropriate, and the modifications may be included in the scope of the present invention as long as they include the features of the present invention. In addition, the elements of the above-described embodiment and the following modifications may be combined to the extent technically possible, and the combinations of these may be included in the scope of the present invention as long as they include the features of the present invention.

[0054] For example, in the above embodiment, the plunger 6 is described as an example of the extrusion part, but a screw-type extrusion part may be used. For example, a screw that rotates around the axial direction A is used as the extrusion part, and the resin raw material is extruded downstream by this rotation.

[0055] In the above embodiment, the groove 41 on the surface of the heat transfer member 23 is formed in a spiral shape, but the groove 41 may be formed in other shapes. For example, the groove 41 may be formed on the surface of the heat transfer member 23 so as to extend in the axial direction A and be parallel to the axial direction A, or may be formed so as to extend in the circumferential direction and be perpendicular to the axial direction A. [Explanation of symbols]

[0056] 1: Injection molding machine 2: Barrel 3: Nozzle 6: Plunger (extrusion part) 8: Rod 9: Head 9a: End 18: Internal heater (internal heating part) 23: Heat transfer material 41: Groove 42a, 42b: Wall A: Axial direction R: Resin raw material (molding material)

Claims

1. A hollow barrel extending in one direction; a nozzle provided at one end side of the barrel in the one direction and configured to inject a molding material plasticized within the barrel; an extrusion section that extrudes the molding material supplied inside the barrel toward the nozzle; A rod extending in the one direction through the extrusion portion; a head provided at an end of the rod on the nozzle side; An internal heating portion provided inside the rod and extending in the one direction; a heat transfer member that contacts the internal heating portion and extends into the head along the one direction, has a groove formed on a surface along the one direction that extends in the one direction, and has a coefficient of thermal expansion higher than that of the head; An injection molding machine comprising:

2. 2. The injection molding machine according to claim 1, wherein the groove extends in the one direction in a spiral shape on a surface of the heat transfer member extending in the one direction.

3. 3. The injection molding machine according to claim 1, wherein the heat transfer member has a cylindrical shape that is elongated along the one direction, and a plurality of the grooves are formed at equal intervals in the circumferential direction.

4. 3. The injection molding machine according to claim 1, wherein in a cross section perpendicular to a direction in which the heat transfer member extends, the groove has a shape in which two wall surfaces constituting the groove are in contact with each other on the central axis side of the heat transfer member, and the distance between the two wall surfaces increases radially outward.

5. 3. The injection molding machine according to claim 1, wherein the heat transfer member has a higher thermal conductivity than the head.

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