Injection molding machine

Abstract

To provide an injection molding machine capable of suppressing stagnancy of a plasticized molding material.SOLUTION: An injection molding machine 1 comprises: a hollow barrel 2 that extends in one direction; a nozzle 3 provided on one end side of the barrel 2 in the one direction so as to inject a molding material plasticized in the barrel 2; a plunger 6 for extruding the molding material supplied to the inside of the barrel 2 toward the nozzle 3 side; a rod 8 that penetrates the plunger 6 in the one direction and extends in the one direction of the barrel 2, and having a torpedo 16 on an end portion on the nozzle 3 side from the plunger 6 in the one direction; a head 9 provided on the end portion on the nozzle 3 side in the one direction of the rod 8; and a ring 10 provided so as to surround a part of the head 9 between the torpedo 16 and the head 9 of the rod 8, and provided with tapered portions 10b each having a slope in a circumferential direction on the nozzle 3 side.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 materials such as resin raw materials using an injection molding machine (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-132039 A Summary of the Invention [Problem to be solved by the invention]

[0004] In an injection molding machine, the molding material is plasticized inside before being injected, but there is a possibility that the plasticized molding material may remain. If the plasticized molding material remains, it may accelerate thermal degradation, causing adhesion or the like, which may affect the molded product. In the case of a configuration in which a ring is provided between the torpedo and the head (stopper) as in Patent Document 1, the molding material may remain around the ring or the head, for example.

[0005] In view of the above problems, an object of the present invention is to provide an injection molding machine capable of suppressing retention of plasticized molding material. [Means for solving the problem]

[0006] 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 that penetrates the extrusion section in the one direction and extends in the one direction of the barrel and has a torpedo at an end thereof closer to the nozzle in the one direction than the extrusion section, a head provided at an end of the rod closer to the nozzle in the one direction, and a ring provided between the torpedo and the head of the rod so as to surround a portion of the head and having a tapered section with a circumferential slope on the nozzle side.

[0007] Furthermore, the ring moves in the one direction together with the rod and the head, and when the ring moves toward the nozzle in the one direction, the tapered portion causes the molding material to flow in the circumferential direction.

[0008] The ring is provided with a plurality of tapered portions in the circumferential direction on the nozzle side in the one direction.

[0009] The ring has the tapered portions spaced at equal intervals in the circumferential direction. Effect of the Invention

[0010] According to the injection molding machine of the present invention, retention of plasticized molding material can be suppressed. [Brief description of the drawings]

[0011] [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] FIG. 2 is a perspective view showing a specific configuration in which the head and the non-return ring in FIG. 1 are combined. [Diagram 3] FIG. 2 is a side view showing a specific configuration of the check ring of FIG. [Figure 4]FIG. 2 is a diagram showing an example of a first step of injection molding using the injection molding machine of FIG. [Diagram 5] 3 is a diagram showing an example of a second step of injection molding using the injection molding machine of FIG. 1. FIG. [Figure 6] 3 is a diagram showing an example of a third step of injection molding using the injection molding machine of FIG. 1. FIG. [Figure 7] 1. FIG. 4 is a diagram showing an example of a fourth step of injection molding using the injection molding machine of FIG. [Figure 8] 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

[0012] 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.

[0013] === 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.

[0014] 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 that is resistant to corrosion by the fluororesin.

[0015] 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".

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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).

[0020] 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.

[0021] The plunger 6 is an extrusion part that extrudes the resin raw material supplied inside the barrel 2 toward the nozzle 3 inside the barrel 2. The plunger 6 is provided so as to fit into an open port 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.

[0022] 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.

[0023] 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.

[0024] 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, the outer diameter of torpedo 16 at downstream end 16b has a gear shape, and many protrusions are formed on end 16b.

[0025] 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 from an upstream end connected to a power source (not shown) toward the downstream side, 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.

[0026] The head 9 is provided at the end of the rod 8 on 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. Specifically, the end 9a of the head 9 is provided with a tapered surface 9c whose outer diameter increases from the upstream side to the downstream side. As described later, the end 9a has a gear shape with a plurality of protrusions 9d provided on the tapered surface 9c. In addition, the surface of the head 9 facing the nozzle 3 downstream of the tapered surface 9c has a substantially conical shape with its apex extending toward the nozzle 3 side.

[0027] 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.

[0028] The non-return ring 10 is provided between the torpedo 16 and 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.

[0029] 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 .

[0030] 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.

[0031] 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.

[0032] <Specific configuration example of check ring> Figures 2 and 3 are diagrams illustrating a specific configuration of the check ring 10. Figure 2 shows a perspective view of the head 9 and the check ring 10 combined, and Figure 3 shows a side view of the check ring 10. In Figures 2 and 3, the direction toward the downstream side (nozzle 3 side) in the axial direction A is shown as the injection direction I.

[0033] 2, a check ring 10 is provided on the head 9. In addition, a plurality of protrusions 9d extending in a direction perpendicular to the central axis are provided on the tapered surface 9c at the end 9a of the head 9. The protrusions 9d function as stoppers that prevent the check ring 10 from slipping off downstream.

[0034] The check ring 10 includes a ring portion 10a and a tapered portion 10b. The ring portion 10a and the tapered portion 10b are integrally formed as the check ring 10. The check ring 10 may be configured with the ring portion 10a and the tapered portion 10b as separate members. The ring portion 10a is annular so as to surround a part of the head 9 upstream of the end portion 9a. Since the head 9 passes through the hole of the ring portion 10a, the check ring 10 can freely move between the rod 8 and the head 9 without being fixed to them. The tapered portion 10b is provided on the surface of the ring portion 10a on the nozzle 3 side, which is the downstream side of the ring portion 10a.

[0035] The check ring 10 is provided with a plurality of tapered portions 10b in the circumferential direction of the ring portion 10a. The tapered portions 10b are preferably provided at equal intervals in the circumferential direction. That is, the distance between the tapered portions 10b is equal in the circumferential direction. For example, the circumferential distance between the tapered portions 10b is shorter than the length of one tapered portion 10b. The protrusion 9d of the head 9 is located between the tapered portions 10b. In this embodiment, the check ring 10 has four tapered portions 10b.

[0036] The tapered portion 10b has one end connected to the ring portion 10a in the axial direction A, and the other end is an inclined surface 40. That is, the downstream side (the nozzle 3 side) of the tapered portion 10b is the inclined surface 40. The inclined surface 40 is a surface inclined with respect to the axial direction A. As shown in FIG. 3, specifically, the inclined surface 40 is a surface (flat surface) that is not perpendicular to the axial direction A (or the injection direction I) and has a predetermined angle greater than 0 degrees and smaller than 90 degrees with respect to the axial direction A (or the injection direction I). The inclined surface 40 is inclined along the circumferential direction with respect to the axial direction A, and the length of the axial direction A at one end side of the tapered portion 10b in the circumferential direction is different from the length of the axial direction A at the other end side of the circumferential direction. The angle of the inclined surface 40 with respect to the axial direction A can be set appropriately. When the check ring 10 moves in the injection direction I, the inclined surface 40 causes the plasticized resin raw material to flow in the direction L.

[0037] The inner surface of the tapered portion 10b faces the tapered surface 9c of the head 9, and is therefore inclined so that the outer diameter increases toward the downstream side in the axial direction A in accordance with the tapered surface 9c of the head 9.

[0038] <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 4 to 8. Figures 4 to 8 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 attached to the nozzle 3.

[0039] (1st process: material supply process) Fig. 4 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.

[0040] (2nd process: 1st plasticization process) FIG. 5 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. The rod 8 and the plunger 6 are moved from the upstream side to the downstream side, and the supply port 2d of the barrel 2 is closed by the plunger 6. In addition, the resin raw material R is brought into contact with the tapered surface 20b by the pressing force of the plunger 6 and heated, and the pellet-shaped resin raw material R is plasticized. Then, the process proceeds to the third step.

[0041] (3rd step: 2nd plasticization step) FIG. 6 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. This 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 check ring 10 and the head 9, and moves downstream of the head 9, that is, toward the nozzle 3 of the barrel 2. Then, the resin J that has been plasticized and is ready for molding is stored at the tip of the barrel 2 on the nozzle 3 side. The internal pressure of this stored resin J pushes the torpedo 16 up upstream. Then, proceed to the fourth step.

[0042] (4th process: Weighing process) Figure 7 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 resin J 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.

[0043] (5th process: injection process) Fig. 8 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 in the injection direction I, and the resin J stored on the nozzle 3 side is injected from the nozzle hole 3a of the nozzle 3 toward the mold.

[0044] The non-return ring 10 moves in the axial direction A together with the rod 8 and the head 9. In particular, when moving in the injection direction I, which is a movement toward the downstream side in the axial direction A, the head 9 moves while pushing the resin J into the nozzle 3. At this time, the tapered portion 10b of the non-return ring 10 moves in the injection direction I, and the inclined surface 40 and the resin J come into contact with each other. Then, since the inclined surface 40 moves in the injection direction I, the resin J that comes into contact with the inclined surface 40 is subjected to a force in a direction different from the injection direction I by the inclined surface 40. Specifically, the resin J is moved in a circumferential direction (direction L in FIG. 2) with respect to the axial direction A by the inclined surface 40. Note that "the resin J is moved in the circumferential direction" includes a case where the moving direction has only a circumferential component (no axial A component) and a case where the moving direction has a circumferential component and an axial A component.

[0045] In this way, when the rod 8 is moved in the injection direction I, the tapered portion 10b of the check ring 10 can move the resin J in the circumferential direction. This action occurs in each of the tapered portions 10b provided on the check ring 10, moving the resin J in the circumferential direction. In other words, the resin J is not only pushed downstream, but also caused to flow in the circumferential direction.

[0046] Then, a pressure holding process is performed to apply a holding pressure to prevent the resin J filled in the mold from flowing back into the injection molding machine 1.

[0047] 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.

[0048] <Action and effect> As described above, in this embodiment, the check ring 10 is provided with the tapered portion 10b having a circumferential inclination on the downstream side, so that the plasticized resin raw material in contact with the inclined surface 40 of the tapered portion 10b can be moved by utilizing the inclination of the inclined surface 40. In particular, when the check ring 10 moves in the injection direction I together with the rod 8 and the head 9, the tapered portion 10b can move the plasticized resin raw material in the circumferential direction, which is a direction different from the axial direction A.

[0049] The tapered portion 10b allows the plasticized resin raw material to flow in the circumferential direction, thereby preventing the plasticized resin raw material from stagnating. Since the plasticized resin raw material is prevented from stagnating, for example, the resin raw material is prevented from stagnating and solidifying, which can cause contamination.

[0050] In addition, by providing multiple tapered portions 10b in the circumferential direction in the check ring 10, it is possible to flow the plasticized resin raw material in the circumferential direction in each of the tapered portions 10b, thereby improving the fluidity.

[0051] In addition, since the tapered portions 10b are provided at equal intervals in the circumferential direction in the check ring 10, the fluidity can be made equal in the circumferential direction, and a decrease in fluidity at specific locations can be suppressed.

[0052] <<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.

[0053] 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.

[0054] In addition, in the present embodiment, the check ring 10 has four tapered portions 10b as an example, but the number of tapered portions 10b is not limited.

[0055] In addition, in the present embodiment, the head 9 is provided with four protrusions 9d, but the number of protrusions 9d is not limited. For example, the number can be appropriately set according to the number of tapered portions 10b of the check ring 10.

[0056] In this embodiment, an example of the inclined surface 40 of the check ring 10 is shown in FIGS. 2 and 3, but the angle of the inclined surface 40 with respect to the axial direction A is not limited to the angle shown in FIGS.

[0057] In this embodiment, an example of the inclined surface 40 of the check ring 10 is shown in Figs. 2 and 3, and an example is shown in which the inclined surface 40 is inclined at a certain angle, but the inclined surface 40 may be a curved surface. [Explanation of symbols]

[0058] 1: Injection molding machine 2: Barrel 3: Nozzle 6: Plunger (extrusion part) 8: Rod 9: Head 10: Check ring (ring) 10b: Tapered section 16: Torpedo A: Axial direction L: Direction (circumferential 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 in the barrel; an extrusion section that extrudes the molding material supplied inside the barrel toward the nozzle; a rod that penetrates the extrusion portion in the one direction, extends in the one direction of the barrel, and has a torpedo at an end portion on the nozzle side relative to the extrusion portion in the one direction; a head provided at an end of the rod on the nozzle side in the one direction; a ring provided between the torpedo and the head of the rod so as to surround a part of the head, the ring having a tapered portion on the nozzle side, the tapered portion having a circumferential inclination; An injection molding machine comprising:

2. 2. The injection molding machine according to claim 1, wherein the ring moves in the one direction together with the rod and the head, and when the ring moves toward the nozzle in the one direction, the tapered portion causes the molding material to flow in a circumferential direction.

3. 3. The injection molding machine according to claim 1, wherein the ring is provided with a plurality of tapered portions in a circumferential direction on the nozzle side in the one direction.

4. 3. The injection molding machine according to claim 1, wherein the ring has tapered portions spaced at equal intervals in a circumferential direction.

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