JP2023148242A - Injection molding machine - Google Patents

Abstract

To provide an injection molding machine capable of reducing the size and shortening the duration of the plasticizing process.SOLUTION: An injection molding machine 1 of the present invention comprises: a barrel 2 provided with its one end having a nozzle 3 for injecting plasticized molding material; a heater 4 provided on the outer peripheral surface 2a of the barrel 2 to heat the molding material inside the barrel 2 through the barrel 2; a plunger 6 for pushing the molding material supplied into the barrel 2 to one end inside the barrel 2; and a rod 8 provided inside the barrel 2 and movable in an axial direction A of the barrel 2, having a torpedo 16 with a tapered portion formed at one end in the axial direction A that narrows from that one end to the other end, wherein the inner peripheral surface 2b of the barrel 2 has a tapered surface 20b whose inner diameter narrows from the other end to the one end in the axial direction A within the range opposite the portion where the heater 4 is provided in the outer peripheral surface 2a of the barrel 2.SELECTED DRAWING: Figure 1

Description

The present invention relates to an injection molding machine that injects plasticized molding material.

Conventionally, parts for automobiles and the like have been molded by using injection molding machines and injecting molding materials such as resin raw materials. As such an injection molding machine, for example, Patent Document 1 listed below discloses an injection molding machine that includes a barrel and a screw provided in the barrel. This injection molding machine is called a screw-type injection molding machine, and uses a single screw in the barrel to gradually plasticize the resin raw material while feeding it to the nozzle side, so the screw and barrel are long. ing.

Further, for example, Patent Document 2 below describes an injection molding machine that is miniaturized and includes a barrel, a rod that is movable in the axial direction within the barrel, and a torpedo provided in the middle of the rod. A molding machine is disclosed. In this injection molding machine, the torpedo can be moved in the axial direction by moving the rod. As a result, the resin raw material is plasticized by moving the torpedo in one direction from the nozzle side of the barrel to the opposite side, and the plasticized resin is injected by moving the torpedo in the other direction. . Therefore, compared to the screw-type injection molding machine disclosed in Patent Document 1, the length of the barrel can be made shorter in the axial direction, so that size reduction can be achieved.

Patent No. 2015-189212 JP 2017-132039 Publication

By the way, it is known that resin raw materials having a high melting point and high specific heat, such as fluororesin, are difficult to plasticize. When the small injection molding machine disclosed in Patent Document 2 is used for injection molding of such resin raw materials, the plasticization process takes more time than the screw-type injection molding machine disclosed in Patent Document 1. The drawback was that it took a lot of time, making it unsuitable for mass production. Therefore, in small-sized injection molding machines, there is room for improvement in terms of shortening the time of the plasticizing process.

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide an injection molding machine that can be downsized and shorten the time required for the plasticizing process.

An injection molding machine according to a first aspect of the present invention includes a barrel in which a nozzle for injecting plasticized molding material is provided on one end side, and a nozzle injected into the barrel through the barrel. a heating part that heats the molding material; an extrusion part that pushes out the molding material supplied to the inside of the barrel toward the one end side; and an extrusion part provided inside the barrel and an axis of the barrel a rod movable in the axial direction, the rod having a torpedo formed at the one end side in the axial direction and having a tapered portion that becomes narrower from the one end side to the other end side, the inner circumferential surface of the barrel; has a tapered surface whose inner diameter becomes narrower from the other end toward the one end in the axial direction, in a region of the outer circumferential surface of the barrel that faces the portion where the heating section is provided.

Further, in the injection molding machine according to the first aspect of the present invention, the inner circumferential surface of the barrel is located in the range with the tapered surface, and is located closer to the one end in the axial direction than the tapered surface. and another surface having substantially the same inner diameter along the axial direction.

Moreover, the injection molding machine according to the first aspect of the present invention further includes an internal heating section provided inside the rod.

Moreover, in the injection molding machine according to the first aspect of the present invention, the internal heating section extends inside the torpedo.

In the injection molding machine according to the first aspect of the present invention, the extrusion section is a direct-acting type that moves along the axial direction, or a screw type that rotates around the axial direction.

According to the present invention, it is possible to provide an injection molding machine that can be downsized and shorten the time for the plasticizing process.

1 is a schematic cross-sectional view showing a schematic configuration of an injection molding machine according to a first embodiment. 2 is a conceptual diagram showing a first step of injection molding using the injection molding machine of FIG. 1. FIG. 2 is a conceptual diagram showing a second step of injection molding using the injection molding machine of FIG. 1. FIG. 2 is a conceptual diagram showing a third step of injection molding using the injection molding machine of FIG. 1. FIG. 2 is a conceptual diagram showing a fourth step of injection molding using the injection molding machine of FIG. 1. FIG. 2 is a conceptual diagram showing a fifth step of injection molding using the injection molding machine of FIG. 1. FIG. FIG. 2 is a schematic cross-sectional view showing a schematic configuration of an injection molding machine according to a second embodiment.

---First embodiment--
DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the accompanying drawings. In order to facilitate understanding of the description, the same elements or elements having the same function are given the same reference numerals as much as possible in each drawing, and redundant description will be omitted.

<Overall configuration>
FIG. 1 is a schematic cross-sectional view showing a schematic configuration of an injection molding machine 1 according to the first embodiment. For convenience of explanation, in FIG. 1, only one side (right side in the paper) with respect to the axis X of the rod 8 and check ring 14 is shown as a cross section, and the rod 8 and check ring 14, which will be described later, are shown as a cross section. On the other hand, the other side (left side in the paper) is shown as a side surface.

As shown in FIG. 1, an injection molding machine 1 internally plasticizes a resin raw material as a molding material and injects the plasticized resin raw material to the outside of a mold or the like. The injection molding machine 1 includes, for example, a barrel 2, a heater 4, a plunger 6, a rod 8, and a material supply section 10.

The barrel 2 has a cylindrical shape. Hereinafter, the axial direction of the barrel 2 will be referred to as axial direction A. A nozzle 3 is provided at one end of the barrel 2 in the axial direction A. The nozzle 3 has a nozzle hole 3a, and injects the plasticized resin raw material from the nozzle hole 3a toward the outside of the mold or the like. In FIG. 1, the nozzle 3 is shown as an open nozzle with an open nozzle hole 3a, but the nozzle 3 may be a shut-off nozzle having a valve that can open and close the nozzle hole 3a. Hereinafter, in the axial direction A, one end side of the barrel 2 where the nozzle 3 is provided (the resin raw material injection side) will be referred to as the "lower side." Further, the other end side of the barrel 2 opposite to the nozzle 3 (the resin raw material supply side) in the axial direction A will be referred to as the "upper side".

The barrel 2 has, for example, a large diameter portion 20 that is a portion to which a resin raw material is supplied, and a small diameter portion 22 that is located below the large diameter portion 20 and has a smaller outer diameter than the large diameter portion 20. .

The heater 4 is provided on the outer peripheral surface 2a of the barrel 2. The heater 4 is a heating unit 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 includes a first heater part 4a provided for the large diameter part 20 of the barrel 2, a second heater part 4b provided for the small diameter part 22 of the barrel 2, and a second heater part 4b provided for the nozzle 3. and a nozzle heater section 4c.

The inner peripheral surface 2b of the barrel 2 has a tapered surface 20b that is inclined with respect to the axial direction A, and a tapered surface 20b that is substantially parallel to the axial direction A, in a range that faces the portion where the heater 4 is provided on the outer peripheral surface 2a of the barrel 2. and a parallel surface 22b (another surface). The tapered surface 20b is formed so that the inner diameter becomes narrower from the upper side to the lower side. The tapered surface 20b is formed on the inner circumferential surface 2b of the barrel 2 in a range facing the portion of the outer circumferential surface 2a of the barrel 2 where the first heater portion 4a is provided, that is, at the position of the large diameter portion 20. The tapered surface 20b is formed at a position on the inner peripheral surface 2b of the barrel 2 that is below the movable range of the plunger 6 and above the movable range of the torpedo 16 (the movable range of the plunger 6 and the movable range of the torpedo 16). range).

The parallel surface 22b is located below the tapered surface 20b in the axial direction A, and is formed to have substantially 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 a 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.

The plunger 6 is an extrusion part that pushes out the resin raw material supplied inside the barrel 2 downward inside the barrel 2 . The plunger 6 is provided so as to fit into an open opening 2c formed at the upper 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 has a hollow shape. The plunger 6 is a direct-acting extrusion part that moves along the axial direction A. The plunger 6 is connected to an actuator (not shown) via, for example, a predetermined fixing member 7, and is moved in the axial direction A by the actuator. Note that the plunger 6 may be fixed to the rod 8 so that it can move (interlock) with the movement of the rod 8.

The rod 8 is provided inside the barrel 2 and is movable in the axial direction A. The rod 8 is disposed inside the barrel 2, passing through the through hole 6c of the plunger 6 (inserted into the plunger 6), for example, and extends in the axial direction A of the barrel 2. The rod 8 is connected to an actuator (not shown) via, for example, a predetermined fixing member 9, and is moved in the axial direction A by the actuator.

The rod 8 has a stopper 12 and a torpedo 16. The stopper 12 is provided at the lower end of the rod 8 and faces the nozzle 3 in the axial direction A. The torpedo 16 is formed on the lower side of the rod 8 between the stopper 12 and the plunger 6. Torpedo 16 is integrally formed with rod 8. The torpedo 16 moves along the axial direction A inside the barrel 2 integrally with the rod 8 through movement of the rod 8.

The torpedo 16 has a tapered portion that narrows from the bottom to the top. That is, the torpedo 16 has a tapered surface 16a that is a tapered outer peripheral surface formed such that the outer diameter becomes narrower from the lower side toward the upper side. Further, the torpedo 16 has a gear-shaped outer diameter at the lower end 16b, and a large number of fins are formed at the end 16b.

Further, a check ring 14 is provided between the torpedo 16 and the stopper 12 and can be freely moved between the torpedo 16 and the stopper 12. The check ring 14 prevents the resin raw material flowing from the torpedo 16 toward the nozzle 3 via the check ring 14 and the stopper 12 from flowing back in the opposite direction.

The rod 8 also has an internal heater 18 . The internal heater 18 is an internal heating section that heats the rod 8 from inside. The internal heater 18 extends along the axial direction A at the position of the axial center X of the rod 8 . The internal heater 18 extends downward from an upper end connected to a power source (not shown), and extends at least inside the torpedo 16 to heat the torpedo 16 from the inside. Thereby, the internal heater 18 heats the resin raw material supplied into the barrel 2 via the torpedo 16.

The material supply unit 10 is a part that supplies material to the inside of the barrel 2, and includes a hopper 30, a cylinder 32, a screw 34, and a preheater 36.

The hopper 30 stores pellet-like (granular) resin raw materials and charges the resin raw materials into the cylinder 32 . The cylinder 32 is a cylindrical member provided between the supply port 30a of the hopper 30 and the supply port 2d of the barrel 2, and extends between the supply port 30a and the supply port 2d.

The screw 34 is provided within the cylinder 32 and is rotatable by a material supply motor (not shown). As the screw 34 rotates, the resin raw material charged into 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. The preheater 36 is a heating unit that heats the cylinder 32 from the outside and heats the resin raw material inside the cylinder 32 via the cylinder 32. Thereby, the preheater 36 preheats the resin raw material before supplying the resin raw material into the barrel 2. The preheater 36 heats the resin raw material being rotated within the cylinder 32 by the screw 34 via the cylinder 32 . Thereby, the resin raw material is heated while being stirred, so that it is preheated with a high heat transfer effect.

<Injection molding process>
Next, the process of injection molding a resin raw material using the injection molding machine 1 will be described with reference to FIGS. 2 to 6. 2 to 6 are schematic cross-sectional views of the injection molding machine 1 of FIG. 1, and are conceptual diagrams showing each step of injection molding using the injection molding machine 1. For convenience of explanation, illustration of some components such as the screw 34, stopper 12, and check ring 14 in FIG. 1 is omitted in FIGS. 2 to 6. Although not shown in the drawings, it is assumed that the nozzle 3 is actually equipped with a mold for injecting the plasticized resin raw material.

FIG. 2 is a conceptual diagram showing the first step of injection molding using the injection molding machine 1 of FIG. As shown in FIG. 2, in the first step (material supply step), a predetermined amount of pellet-shaped resin raw material R is supplied into the barrel 2 by the material supply section 10. At this time, the temperature inside the cylinder 32 is rising due to the heating of the cylinder 32 by the preheater 36. Thereby, the resin raw material R is preheated before being supplied into the barrel 2. Moreover, the plunger 6 is located on the open port 2c side of the barrel 2 in the axial direction A, and the supply port 2d of the barrel 2 is in an open state. The resin raw material R is supplied between the plunger 6 and the torpedo 16 from the supply port 2d of the barrel 2. At this time, the temperature inside the barrel 2 is rising due to the heating of the barrel 2 by the first heater section 4a and the second heater section 4b and the heating of the rod 8 by the internal heater 18. Then, proceed to the second step.

FIG. 3 is a conceptual diagram showing the second step of injection molding using the injection molding machine 1 of FIG. 1. In the second step (plasticizing step), the rod 8 and the plunger 6 are moved from the upper side to the lower side, so that the supply port 2d of the barrel 2 is closed by the plunger 6. This prevents the plasticized resin raw material R from flowing back toward the material supply section 10 side. Further, the resin raw material R is pressed against the tapered surface 20b of the barrel 2 by the pressing force of the plunger 6. This tapered surface 20b is a portion facing the outer circumferential surface 2a heated by the first heater portion 4a, and is a portion of the inner circumferential surface 2b of the barrel 2 that tends to have a particularly high temperature. When the resin raw material R comes into contact with such a high-temperature tapered surface 20b, the resin raw material R is plasticized. In addition, at this time, the tapered surface 16a of the torpedo 16 faces the parallel surface 22b of the barrel 2, and is indirectly heated by the heating of the small diameter portion 22 of the barrel 2 by the second heater portion 4b, thereby increasing the temperature. . Then, proceed to the third step.

FIG. 4 is a conceptual diagram showing the third step of injection molding using the injection molding machine 1 of FIG. 1. As shown in FIG. 4, in the third step (plasticizing step), the torpedo 16 is moved from the lower side to the upper side through the movement of the rod 8. At this time, the plunger 6 is not moved and the supply port 2d of the barrel 2 is kept closed by the plunger 6. The resin raw material R pushed in by the plunger 6 contacts not only the tapered surface 20b of the barrel 2 but also the tapered surface 16a of the torpedo 16. The temperature of this tapered surface 16a is increased by heating the small diameter portion 22 of the barrel 2 by the second heater portion 4b in the second step, and is also directly heated by the internal heater 18, resulting in a temperature increase. . When the resin raw material R comes into contact with such a tapered surface 16a, the resin raw material R is plasticized. Then, the resin raw material R passes through the gap between the fin of the end 16b of the torpedo 16 and the inner peripheral surface 2b of the barrel 2 in the direction of the arrow, passes through the gap between the check ring 14 and the stopper 12, and then passes through the barrel. 2 to the nozzle 3 side. Even while passing through these gaps, the resin raw material R is plasticized by heating by the first heater section 4a, second heater section 4b, and internal heater 18 and by the action of shear stress. The resin J is then completely plasticized and transformed into a moldable resin J, which is stored at the tip of the barrel 2 on the nozzle 3 side. The internal pressure of this accumulated resin J pushes the torpedo 16 upward. Then, proceed to the fourth step.

FIG. 5 is a conceptual diagram showing the fourth step of injection molding using the injection molding machine 1 of FIG. 1. In the fourth step (measuring step), the position of the torpedo 16 is controlled so that the resin J stored on the nozzle 3 side in the barrel 2 reaches a set amount. That is, the torpedo 16 is stopped at a position where a set amount of resin J necessary for injection molding has accumulated. At this time, the plunger 6 is not moved and the supply port 2d of the barrel 2 is maintained closed by the plunger 6. Then, proceed to the fifth step.

FIG. 6 is a conceptual diagram showing the 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 downward, and the resin J stored on the nozzle 3 side in the barrel 2 is injected from the nozzle hole 3a of the nozzle 3 toward the mold. Subsequently, 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, and the fifth step is completed.

After the fifth step, the process moves to a step of cooling the resin J filled in the mold, and after cooling is completed, the mold is opened and the molded product is taken out, thereby completing one molded product. In addition, by returning to the first step in parallel with this cooling step and repeating the first to fifth steps, molded products can be continuously produced. In addition, when repeating the process, material supply into the barrel 2 as explained in the first process is performed between the fourth process and the fifth process, and the first process is omitted after the fifth process. Then, the process may proceed to the second step. That is, after the plasticizing and metering process of the resin raw material R, the plunger 6 is moved upward to open the supply port 2d of the barrel 2, and the material for the next injection molding is supplied from the supply port 2d. The process may proceed to an injection process, and after the injection process, the process may directly proceed to the next plasticizing process.

<Effect>
As described above, according to the injection molding machine 1 according to the present embodiment, the resin raw material R is plasticized by moving the torpedo 16 from the lower side to the upper side through the movement of the rod 8, and the torpedo 16 is moved from the upper side to the lower side. By moving it to the side, the plasticized resin J can be injected. In this way, the plasticizing process and the injection process can be performed by moving the torpedo 16, which is different from the conventional screw-type injection method in which the resin raw material is gradually plasticized while being fed to the nozzle side with a single screw in the barrel. Compared to a molding machine, it can be made smaller. Furthermore, in this embodiment, since the inner circumferential surface 2b of the barrel 2 has the tapered surface 20b, the cross-sectional area is reduced at the tapered surface 20b, so that the resin raw material R is contacts the tapered surface 20b. This tapered surface 20b is a portion facing the outer circumferential surface 2a heated by the first heater portion 4a, and is a portion of the inner circumferential surface 2b of the barrel 2 that tends to have a particularly high temperature. By bringing the resin raw material R into contact with such a high-temperature tapered surface 20b, the resin raw material R can be plasticized with a high heat transfer effect. In addition, since the cross-sectional area also decreases in the tapered surface 16a of the torpedo 16 located below the tapered surface 20b of the barrel 2, the resin raw material R also comes into contact with this tapered surface 16a and becomes plasticized. . In this way, by performing plasticization in two stages on the tapered surface 20b of the barrel 2 and the tapered surface 16a of the torpedo 16, the heat transfer effect to the resin raw material R can be further enhanced. It can save time. As described above, it is possible to achieve miniaturization and shorten the time of the plasticizing process.

Further, according to the present embodiment, the inner circumferential surface 2b of the barrel 2 has a tapered surface 20b and a parallel surface 22b in a range facing the portion of the outer circumferential surface 2a of the barrel 2 where the heater 4 is provided. The tapered surface 20b of the barrel 2 contacts the resin raw material R due to its reduced cross-sectional area and becomes a part from which heat is removed, whereas the parallel surface 22b of the barrel 2 has a lower temperature because heat is less likely to be removed than from the tapered surface 20b. This will be the higher part. Therefore, in the plasticizing process, when the temperature of the tapered surface 16a increases due to heating by the second heater part 4b, the temperature of the tapered surface 16a increases because the tapered surface 16a faces the parallel surface 22b, which has a higher temperature. can be raised more efficiently. As a result of the tapered surface 16a having a higher temperature coming into contact with the resin raw material R, the time for the plasticizing step can be more suitably shortened.

Further, according to this embodiment, the interior of the barrel 2 can be heated not only from the outside of the barrel 2 but also from the inside by the internal heater 18 provided inside the rod 8. Furthermore, the torpedo 16 itself can also be directly heated by the internal heater 18. Therefore, the temperature of the tapered surface 20b and the tapered surface 16a can be further increased by the internal heater 18, and the heat transfer effect of the tapered surface 20b and the tapered surface 16a to the resin raw material R can be improved. As a result, the time for the plasticizing step can be more suitably shortened. Furthermore, in conventional screw-type injection molding machines, since the screw provided inside the barrel rotates, it is difficult to install a heater inside the barrel. Since the internal heater 18 is provided for the rod 8 (non-rotating member) that moves in the direction A, the internal heater 18 can be easily provided.

Further, according to the present embodiment, since the internal heater 18 extends inside the torpedo 16, the heat transfer effect of the tapered surface 16a of the torpedo 16 to the resin raw material R is further enhanced, and the above-mentioned effect is suitably achieved. play.

Further, according to the present embodiment, since the extrusion part that extrudes the resin raw material R into the barrel 2 is a direct-acting plunger 6, the resin raw material R has high viscosity and poor fluidity in a heated state. It is effective for

---Second embodiment--
Next, with reference to FIG. 7, an injection molding machine 1A according to a second embodiment will be described. In the second embodiment, the same reference numerals are given to the same configurations or functions as in the first embodiment, and explanations are omitted as appropriate, and points different from the first embodiment will be explained. FIG. 7 is a schematic cross-sectional view showing a schematic configuration of an injection molding machine 1A according to the second embodiment. For convenience of explanation, in FIG. 7, only the side (right side in the paper) of the rod 8, check ring 14, and screw 40 (described later) with respect to the axis X of the rod 8, check ring 14, and screw 40 is shown. It is shown as a cross section, and the other side (left side in the paper) with respect to the axis X is shown as a side surface.

As shown in FIG. 7, the injection molding machine 1A according to the second embodiment also includes a barrel 2, a heater 4, a rod 8, a material supply section 10, like the injection molding machine 1 according to the first embodiment. Equipped with The injection molding machine 1A according to the second embodiment includes a screw 40 instead of the plunger 6, and further includes a needle throttle valve 50 provided at the tip (lower end) of the rod 8. This is different from the injection molding machine 1 according to the first embodiment.

The screw 40 is an extrusion section that pushes out the resin raw material R supplied inside the barrel 2 downward inside the barrel 2 . The screw 40 is provided so as to fit into the opening 2c of the barrel 2. A through hole 40c through which the rod 8 passes is formed in the center of the screw 40. That is, the screw 40 is hollow. In the second embodiment, the rod 8 is disposed inside the barrel 2 so as to pass through the through hole 40c of the screw 40 (inserted into the screw 40).

The screw 40 is a screw-shaped extrusion section that rotates around the axial direction A as a rotation center. The screw 40 is connected to a motor (not shown) via, for example, a predetermined power transmission mechanism 42, and is rotated by the motor. The screw 40 continuously pushes out the resin raw material R supplied into the barrel 2 by the driving force generated by rotation, and brings it into contact with the tapered surface 20b of the barrel 2 and the tapered surface 16a of the torpedo 16. For example, the screw 40 stops rotating at least during the injection process, and continues to rotate at other times.

The needle throttle valve 50 is provided on the stopper 12 side of the rod 8. The needle throttle valve 50 is movable in the axial direction A as the rod 8 moves in the axial direction A. The needle throttle valve 50 adjusts the opening degree of the nozzle hole 3a of the nozzle 3 by moving in the axial direction A. The needle throttle valve 50 adjusts the amount of resin J injected from the nozzle hole 3a toward the outside of the mold or the like by adjusting the opening degree of the nozzle hole 3a.

<Effect>
As described above, also in the injection molding machine 1A according to the second embodiment, the plasticizing process and the injection process can be performed by moving the torpedo 16, so that size reduction can be achieved. Furthermore, the tapered surface 20b of the barrel 2, which has a high temperature, has a high heat transfer effect on the resin raw material R, and the tapered surface 20b of the barrel 2 and the tapered surface 16a of the torpedo 16 perform plasticization in two stages. By doing so, the heat transfer effect to the resin raw material R can be further enhanced. As a result, the time required for the plasticizing process can be shortened. As described above, it is possible to achieve miniaturization and shorten the time of the plasticizing process.

Furthermore, when the resin raw material R is pushed out by the plunger 6 as in the first embodiment, plasticization can only be performed during the stroke in which the plunger 6 moves downward, and the plasticization becomes intermittent. On the other hand, according to the second embodiment, the resin raw material R can be continuously extruded by the driving force generated by the rotation of the screw 40 and brought into contact with the tapered surface 20b and the tapered surface 16a, so that continuous plasticization becomes possible. Further, according to the second embodiment, the contact surface area of the resin raw material R with the inner peripheral surface 2b of the barrel 2 can be further increased by the screw 40 compared to the first embodiment, so that the heat transfer effect can be further improved. can be increased. With the above, the time for the plasticizing step can be more suitably shortened.

Further, according to the second embodiment, the extrusion part that extrudes the resin raw material R into the barrel 2 is of a screw type, which is effective in plasticizing the resin raw material R which has low viscosity and good fluidity in a heated state. It is.

Further, according to the second embodiment, by providing the needle throttle valve 50, even when the amount of resin J increases due to continuous plasticization, the injection amount can be adjusted to be appropriate.

<Modified example>
The present invention is not limited to the embodiments described above. In other words, the above-described embodiments may be modified as appropriate by those skilled in the art, as long as they have the characteristics of the present invention. Furthermore, the elements of the above-described embodiment and the modified examples described below can be combined to the extent technically possible, and combinations of these are also included within the scope of the present invention as long as they include the features of the present invention. .

For example, the extrusion part that extrudes the resin raw material R into the inside of the barrel 2 may be replaceable with either a direct-acting type or a screw type. For example, if the viscosity of the resin raw material R in a heated state is high, a direct-acting type plunger 6 is used, and if the viscosity is low, a screw type screw 40 is used. May be replaceable.

Further, in the above embodiment, an example in which the torpedo 16 is integrally formed with the rod 8 has been described, but the torpedo 16 may be formed separately from the rod 8 and may be fixed to the rod 8. Moreover, the internal heater 18 of the rod 8 does not necessarily have to extend inside the torpedo 16, and the rod 8 does not necessarily have to have the internal heater 18.

In the above embodiment, an example has been described in which the plunger 6 or the screw 40 as an extrusion part enters into the barrel 2, and the rod 8 passes through the plunger 6 or the screw 40, but the invention is not limited to this. For example, the injection molding machine 1 does not need to be equipped with the plunger 6 and the screw 40, but is equipped with a pushing device outside the barrel 2 as an extrusion unit that pushes out the resin raw material R into the barrel 2, and the injection molding machine 1 is equipped with a pushing device outside the barrel 2 as an extrusion section that pushes out the resin raw material R into the barrel 2, and the injection molding machine 1 is equipped with a pushing device outside the barrel 2 as an extrusion section that pushes out the resin raw material R into the barrel 2, and the injection molding machine The raw material R may be pushed into the barrel 2.

1, 1A: injection molding machine, 2: barrel, 2a: outer peripheral surface of barrel, 2b: inner peripheral surface of barrel, 3: nozzle, 4: heater (heating part), 6: plunger (extrusion part), 8: rod , 16: Torpedo, 18: Internal heater (internal heating part), 20b: Tapered surface, 22b: Parallel surface (other surface), 40: Screw (extrusion part), R: Resin raw material (molding material)

Claims (5)

a barrel having one end provided with a nozzle for injecting plasticized molding material;
a heating section that is provided on the outer peripheral surface of the barrel and heats the molding material inside the barrel through the barrel;
an extrusion unit that extrudes the molding material supplied inside the barrel toward the one end side inside the barrel;
A torpedo is provided inside the barrel and movable in the axial direction of the barrel, and has a tapered portion formed on the one end side in the axial direction and narrows from the one end side toward the other end side. rod and
Equipped with
The inner circumferential surface of the barrel has a tapered surface whose inner diameter narrows from the other end toward the one end in the axial direction, in a range facing the portion where the heating section is provided on the outer circumferential surface of the barrel. An injection molding machine characterized by having: The inner circumferential surface of the barrel includes, in the range, the tapered surface and another surface that is located closer to the one end than the tapered surface in the axial direction and has substantially the same inner diameter along the axial direction. The injection molding machine according to claim 1, characterized in that it has: The injection molding machine according to claim 1 or 2, further comprising an internal heating section provided inside the rod. The injection molding machine according to claim 3, wherein the internal heating section extends inside the torpedo. 3. The injection molding machine according to claim 1, wherein the extruder is a direct-acting type that moves along the axial direction or a screw type that rotates around the axial direction.

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