JP2008105247A - Injection molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the leakage of a molding material from an injection hole when the molding material is supplied from an extrusion nozzle into a metering space, reduce the molding material staying between one end of the metering space and the injection hole, and prevent the occurrence of a temperature distribution in the molding material in the metering space, and the dispersion of product quality. <P>SOLUTION: In an injection molding machine 10, an extruder 16 is set retractably toward the injection hole 11 outside a cylinder 13. When it is moved forward while the tip opening plane 11a of the injection hole 11 and the opening plane 17c of an impregnation hole 17b are separated from each other, the tip opening planes 11a and 16e of the respective inside channels 16c and 16d of the injection hole 11 and the extrusion nozzle 16a are brought into contact with each other so that the injection hole 11 and the inside channels 16c and 16d communicate with each other. The molding material is filled in the metering space 12 from the extrusion nozzle 16a through the injection hole 11. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an injection molding machine used for vulcanization molding of rubber products such as vibration-proof rubber.

As an injection molding machine of this type, for example, as shown in Patent Document 1 below, a cylinder in which an injection hole is formed at one end and a measuring space communicating with the injection hole is formed inside, and the other end of the cylinder A plunger that is slidably supported on the inner wall surface of the metering space on the side, and an extruder that fills the metering space with a molding material in a plasticized state from an extrusion nozzle, the tip opening of the injection hole With the surface in contact with the opening surface of the injection hole communicating with the cavity formed in the mold, the molding material filled in the measurement space is moved forward by the plunger toward the injection hole. A configuration in which the cavity is filled and injected into the cavity is known.
In this injection molding machine, conventionally, when the plunger is moved forward to inject the molding material in the metering space of the cylinder, the molding material stays in the injection passage connecting the injection hole and one end of the metering space. There is a demand for suppressing this. By suppressing the retention of the molding material in this way, it becomes possible to shorten the vulcanization molding cycle by increasing the heating temperature of the molding material in the measurement space and shortening the vulcanization time in the cavity. That is, the retention molding material staying in the injection passage as described above has a residence time in the injection molding machine as compared with a new molding material that is first plasticized in the extruder in the next vulcanization molding step. Since it becomes longer, the set heating temperature in the measuring space needs to be suppressed to such an extent that the staying molding material does not start vulcanization, and cannot be set high. Therefore, there is a problem that it is difficult to shorten the vulcanization molding cycle.
Thus, as a means for reducing such a staying molding material, for example, it is conceivable to shorten the length of the injection passage.
JP 2003-11189 A

However, in this case, when the molding material is supplied into the measuring space from the extrusion nozzle, the molding material may leak from the injection hole. That is, when supplying the molding material from the extrusion nozzle into the metering space, heat from the mold heated to a high temperature is conducted to the injection passage, and in order to prevent the staying molding material in this passage from being burned, Since the tip opening surface of the hole and the opening surface of the injection hole are separated from each other, the injection hole is opened. Therefore, for example, when the length of the injection passage is shortened, the molding material may easily leak from the injection hole due to the flow pressure of the molding material supplied from the extrusion nozzle into the measurement space.
Furthermore, in the conventional injection molding machine, when the molding material in the metering space is injected from the injection hole, the molding material is reversely flown into the internal flow path of the extrusion nozzle in order to prevent the molding material from flowing back into the extrusion machine through the extrusion nozzle. Since the stop valve is provided, heat is radiated from the check valve, and the temperature of the molding material located in the vicinity of the check valve is likely to decrease, and there is a possibility that a temperature distribution is generated in the molding material in the measurement space.
In this case, the vulcanization time in the cavity may become long, or the product quality of the vulcanized molded product may vary.

  The present invention has been made in consideration of such circumstances, and while the molding material staying between one end of the metering space and the injection hole can be reduced, the molding material is supplied into the metering space from the extrusion nozzle. Sometimes it is possible to prevent the molding material from easily leaking from the injection hole, and it is also possible to prevent the temperature distribution from occurring in the molding material in the measuring space, thereby preventing variations in product quality. An object is to provide an injection molding machine.

In order to solve the above problems and achieve such an object, an injection molding machine according to the present invention includes a cylinder having an injection hole formed at one end and a measuring space communicating with the injection hole inside. A plunger supported on the other end side of the cylinder so as to be in sliding contact with the inner wall surface of the metering space, and an extruder for filling the metering space with a molding material in a plasticized state from an extrusion nozzle, With the tip opening surface of the injection hole in contact with the opening surface of the injection hole communicating with the cavity formed in the mold, the molding material filled in the measuring space is directed to the injection hole. An injection molding machine that injects from the injection hole and fills the cavity by the forward movement of the plunger, and the extruder is provided to be movable forward and backward toward the injection hole outside the cylinder, When the front end opening surface of the injection hole and the opening surface of the injection hole are moved away from each other, the front end opening surfaces of the injection hole and the internal flow path of the extrusion nozzle come into contact with each other, and these injection The hole and the internal channel communicate with each other, and the metering space is filled with the molding material from the extrusion nozzle through the injection hole.
According to this invention, when the extruder is moved forward toward the injection hole with the tip opening surface of the injection hole and the opening surface of the injection hole being separated from each other, the internal flow path and the injection hole of the extrusion nozzle Since the molding material is filled into the metering space from the extrusion nozzle through this injection hole, in order to reduce the molding material staying between one end of the metering space and the injection hole, for example, the metering space Even if the injection passage connecting one end of the nozzle and the injection hole is shortened, it is possible to prevent the molding material from leaking from the injection hole when the molding material is supplied to the metering space from the extrusion nozzle.
Further, since the extruder is provided so as to be able to advance and retreat toward the injection hole outside the cylinder, when the molding material is injected from the injection hole, the extruder is moved backward from the injection hole. Can be separated from the measuring space and independent of each other. Therefore, unlike the conventional injection molding machine, there is no need to provide a check valve in the internal flow path of the extrusion nozzle. Therefore, heat is radiated from the check valve, and a temperature distribution is generated in the molding material in the measurement space. Can be prevented. This makes it possible to reliably shorten the vulcanization molding cycle and prevent variations in product quality.

Here, the extruder is provided so as to be slidable in a direction crossing the opening direction of the injection hole, and the opening direction of the internal flow path of the extrusion nozzle is opposite to the opening direction of the injection hole. You may bend so that it may become direction.
In this case, it is possible to easily and surely realize an injection molding machine that exhibits the above-described effects.

Moreover, the space | interval between the front end opening surface of the said injection hole and the end of the said measurement space may be 30 mm or less.
In this case, the molding material staying between the injection hole and one end of the measurement space can be reliably reduced.

Further, an injection flow path that allows the injection hole and the cavity to communicate with each other may be formed in the mold, and a throttle portion may be provided in the injection flow path.
In this case, for example, by shortening the injection passage connecting one end of the measuring space and the injection hole, the molding material staying between the injection hole and one end of the measuring space can be reduced. At that time, even if the temperature rise due to self-heating of the molding material on the cylinder side becomes insufficient, the molding material injected from the injection hole of the mold can be sufficiently heated when passing through the throttle portion. It becomes possible. This makes it possible to reduce the amount of stagnant molding material as described above, but it becomes difficult to shorten the vulcanization time due to the low molding temperature, or molding over the entire area in the cavity. It is possible to prevent occurrence of molding defects such as difficulty in spreading the material evenly.
Further, since the throttle portion is formed in the injection flow path on the mold side rather than the cylinder side, when the molding material is supplied from the extrusion nozzle into the measuring space through the injection hole, the molding material is excessively raised by self-heating. Heating can prevent burning.

  According to the present invention, the molding material staying between one end of the metering space and the injection hole can be reduced. On the other hand, when the molding material is supplied into the metering space from the extrusion nozzle, the molding material easily leaks from the injection hole. It is also possible to prevent the temperature distribution from occurring in the molding material in the measurement space, and to prevent variations in product quality.

Hereinafter, an embodiment of an injection molding machine according to the present invention will be described with reference to FIGS.
This injection molding machine 10 has an injection hole 11 formed at one end and a cylinder 13 in which a measurement space 12 communicating with the injection hole 11 is formed, and an inner portion of the measurement space 12 at the other end of the cylinder 13. A plunger 14 supported so as to be in sliding contact with the wall surface and an extruder 16 that fills the metering space 12 with a molding material in a plasticized state from the extrusion nozzle 16a are provided.

 Then, as shown in FIG. 2, the plunger 14 is moved backward with respect to the injection hole 11 by the flow pressure of the molding material supplied from the extrusion nozzle 16 a into the measurement space 12, and the molding material is supplied to the measurement space 12. After filling, as shown in FIG. 3 and FIG. 4, the tip opening surface 11a of the injection hole 11 is contacted with the opening surface 17c of the injection hole 17b communicating with the cavity 17a formed in the mold 17 therein. In the state of contact, the molding material filled in the metering space 12 is injected from the injection hole 11 by the forward movement of the plunger 14 toward the injection hole 11 and filled into the cavity 17a.

The mold 17 includes an upper mold 17d and a lower mold 17e provided so as to be close to and away from each other, a runner member 17f provided on the surface of the upper mold 17d, and a locate ring 17g provided on the surface of the runner member 17f. The locate ring 17g, the runner member 17f, the upper mold 17d and the lower mold 17e are arranged in this order from the injection hole 11 side.
Here, the locating ring 17g is a cylindrical body formed by coaxially connecting a large diameter portion and a small diameter portion, and the small diameter portion is fitted to the runner member 17f to form the cylindrical body. An upper end opening of a through hole (hereinafter referred to as “injection flow path”) 17h is the injection hole 17b. In this embodiment, the upper die 17d is provided so as to be able to approach and separate from the back surface of the runner member 17f, and the lower die 17e is provided so as to be able to approach and separate from the back surface of the upper die 17d.

In the above configuration, when the upper die 17d moves forward toward the back surface of the runner member 17f and comes into contact with each other, the runner 17k is formed between the 17d and 17f, and the lower die 17e is the back surface of the upper die 17d. A cavity 17a is formed between these 17e and 17d when they move forward toward each other and come into contact with each other. In this way, the upper mold 17d moves forward toward the back surface of the runner member 17f and contacts each other, and the lower mold 17e moves forward toward the back surface of the upper mold 17d and contacts each other. The injection hole 17b communicates with the cavity 17a through the injection flow path 17h and the runner 17k.
Here, the injection molding machine 10 is provided so as to be able to approach and separate from the injection hole 17b formed in the locating ring 17g, and when the injection molding machine 10 reaches the forward end position, the tip of the injection hole 11 is provided. The opening surface 11a and the opening surface 17c of the injection hole 17b come into contact with each other, and the injection hole 11 and the injection hole 17b communicate with each other.

 The plunger 14 is provided so as to be able to advance and retreat with respect to the injection hole 11, and has a tapered portion 19 that is gradually reduced in diameter toward the distal end 18 that faces the injection hole 11, and an outer diameter at the base end 19 a of the tapered portion 19. And a base end portion 20 that is in sliding contact with the inner wall surface of the measuring space 12, and an inclined portion 21 that connects the base end 19a of the taper portion 19 and the tip end 20a of the base end portion 20. . Each of the tapered portion 19 and the inclined portion 21 has an outer peripheral surface extending linearly in a direction inclined in the direction of the central axis O of the plunger 14 in the longitudinal sectional view of the plunger 14, and the proximal end portion 20 is the center of the plunger 14. It has the outer peripheral surface extended along the axis O direction.

  Further, in the longitudinal sectional view of the plunger 14, the angle formed by the outer peripheral surface of the taper portion 19 and the central axis O is smaller than the angle formed by the outer peripheral surface of the inclined portion 21 and the central axis O. Further, the connecting portion between the base end portion 20 and the inclined portion 21, that is, the distal end 20 a of the base end portion 20 is formed in a curved shape that protrudes radially outward of the plunger 14, and the tapered portion 19 and the inclined portion 21. The base end 19a of the tapered portion 19 is formed in a curved surface that is concave inward in the radial direction of the plunger 14. In addition, the tip 18 of the plunger 14 is formed in a curved surface that is convex toward the injection hole 11.

Here, in the measuring space 12 of the cylinder 13, the inner wall surface of the one end side portion 22 in which the injection hole 11 is formed has an inner surface shape along the outer shape of the tapered portion 19 and the inclined portion 21.
In the present embodiment, the measuring space 12 has a measuring space tapered portion 25 that gradually increases in diameter from the injection hole 11 toward the other end side, and has a larger diameter than the inner diameter at the other end 25a of the tapered portion 25. 14, a measuring space base end portion 26 slidably contacting the outer peripheral surface of the base end portion 20, a measuring space connecting the other end 25a of the measuring space taper portion 25 and one end 26a on the injection hole 11 side at the measuring space base end portion 26. And an inclined portion 27. The inner wall surface of the one end side portion 22 of the weighing space 12 described above is constituted by the inner wall surface of the weighing space tapered portion 25 and the inner wall surface of the weighing space inclined portion 27. Here, as described above, the metering space 12 includes the metering space taper portion 25 that gradually increases in diameter from the injection hole 11 toward the other end side. Therefore, in the present embodiment, the tip opening surface 11a of the injection hole 11 is provided. The injection hole 11 constitutes one end of the measurement space 12 so that the interval between the measurement space 12 and one end of the measurement space 12 is 0 mm. That is, in this embodiment, the cylinder 13 is not formed with an injection passage that connects one end of the measurement space 12 and the injection hole 11.

From the above, as shown in FIGS. 1 and 4, when the plunger 14 reaches the forward end position, the outer periphery of each of the tapered portion 19 and the inclined portion 21 with the tip 18 fitted into the injection hole 11. The surface comes into contact with and fits into the inner wall surface of the one end side portion 22 of the measuring space 12.
Here, in the illustrated example, when the plunger 14 reaches the forward end position, the tip 18 of the plunger 14 does not protrude below the injection hole 11 and is positioned radially inward at the opening edge of the injection hole 11. Thus, the tip opening surface 11 a is substantially flush with the injection hole 11.
When the plunger 14 has reached the forward end position as shown in FIGS. 1 and 4, and when it has reached the reverse end position as shown in FIGS. 2 and 3, that is, the measuring space. 12 is filled with a molding material and is in a state immediately before the plunger 14 is moved forward, regardless of whether the outer peripheral surface of the base end portion 20 of the plunger 14 and the inner wall surface of the measurement space base end portion 26 are These materials are in contact with each other to such an extent that the molding material does not substantially flow.

  In the present embodiment, the extruder 16 is provided so as to be able to advance and retreat toward the injection hole 11 outside the cylinder 13, and as shown in FIGS. 1 and 2, the tip opening surface 11 a of the injection hole 11. And the opening surface 17c of the injection hole 17b are moved forward in a state of being separated from each other, the tip opening surfaces 11a and 16e of the injection hole 11 and the internal flow paths 16c and 16d of the extrusion nozzle 16a are in contact with each other, These injection holes 11 communicate with the internal flow paths 16c, 16d of the extrusion nozzle 16a, and the molding space 12 is filled from the extrusion nozzle 16a through the injection holes 11. In the illustrated example, the measuring space 12 and the plunger 14 are extended in the vertical direction, the plunger 14 is provided so as to be able to advance and retract in the vertical direction with respect to the injection hole 11, and the injection hole 11 opens downward in the vertical direction. is doing. The extruder 16 is provided to be able to advance and retreat from the outside of the cylinder 13 in the horizontal direction with respect to the injection hole 11, that is, in the direction orthogonal to the opening direction of the injection hole 11. Here, the extruder 16 is connected to, for example, a fluid pressure cylinder (not shown), and when the cylinder is advanced and retracted, the wheel 16b attached to the extruder 16 rotates on the support plate 15 and the extruder 16 is driven. 16 moves forward and backward with respect to the injection hole 11.

 The internal flow paths 16 c and 16 d of the extrusion nozzle 16 a are bent so that the opening direction is opposite to the opening direction of the injection hole 11. In the illustrated example, the internal flow paths 16c and 16d of the extrusion nozzle 16a are connected to the first flow path 16c that is positioned on the side of the extruder 16 and extends in the horizontal direction, and the tip of the first flow path 16c. A second flow path 16d extending upward in the vertical direction. That is, the opening direction of the internal flow paths 16c and 16d is upward in the vertical direction, and is bent so as to be opposite to the opening direction of the injection hole 11 opening downward in the vertical direction. In the illustrated example, the first flow path 16c and the second flow path 16d are orthogonal to each other.

  Here, the locating ring 17g includes a main body portion 17j and an injection nozzle 17i, and both the 17j and 17i are cylindrical bodies in which a large diameter portion and a small diameter portion are coaxially connected. The small diameter portion 17j is fitted to the runner member 17f as described above. Further, a counterbore hole is formed on the surface of the large-diameter portion of the main body portion 17j, and a female screw portion is formed on the bottom surface of the counterbore hole. A locating ring 17g is configured by screwing a male screw portion formed in a small diameter portion of the injection nozzle 17i to the female screw portion. In this configuration, a through hole extending along the central axis direction is formed inside the locate ring 17g, and this through hole serves as an injection flow path 17h. In the injection flow path 17, a large injection nozzle 17i is formed. An opening opening on the surface of the diameter portion is the injection hole 17b.

  Here, the inside diameter of the counterbore hole is larger than the outer diameter of the large-diameter portion of the injection nozzle 17i, and the injection nozzle 17i is attached to the main body portion 17j and the outer peripheral surface of the injection nozzle 17i and the inner periphery of the counterbore hole. A gap is provided between the surfaces. The injection channel 17h gradually increases in diameter from the injection hole 17b toward the tip of the small-diameter portion of the injection nozzle 17i, and when the tip reaches the through-hole formed in the cylindrical main body portion 17j, the step portion The diameter is then gradually expanded and then gradually increased toward the runner 17k.

 That is, the injection channel 17h gradually increases in diameter from the injection hole 17b toward the tip of the small diameter portion of the injection nozzle 17i, and the opening diameter at the tip of the small diameter portion is a through-hole formed in the cylindrical main body portion 17j. In the hole, it is smaller than the inner diameter of the portion where the tip of the small diameter portion of the injection nozzle 17i is located. In the present embodiment, the through hole formed in the cylindrical injection nozzle 17 i of the injection channel 17 h is the throttle portion 32. Note that the upper end surface of the injection nozzle 17i where the injection hole 17b opens, that is, the opening surface 17c of the injection hole 17b is formed in a convex curved surface.

Here, in this embodiment, the 1st heating means 30 extended along the longitudinal direction is provided in the inside of the extruder 16 over the perimeter of this extruder 16.
A second heating means 31 extending along the direction of the central axis O is provided inside the cylinder 13 so as to surround the measuring space 12 from the outside in the radial direction over the entire circumference. The second heating means 31 is provided inside the cylinder 13 so as to surround the measurement space base end portion 26 of the measurement space 12 from the outside in the radial direction.

  The first and second heating means 30 and 31 can supply a heat medium such as machine oil in a high temperature state to the heat medium passages formed in the extruder 16 and the cylinder 13, respectively. Has been configured. That is, the heating medium passage and a heating medium supply means (not shown) are connected, the heating medium is circulated between them, and the heating medium always heated to a constant temperature can be supplied to the heating medium passage. Yes. The set heating temperature of the first heating unit 30 is equal to or higher than the set heating temperature of the second heating unit 31.

Next, a method for injection molding using the injection molding machine 10 configured as described above will be described.
First, the plunger 14 is made to reach the forward end position, and the extruder 16 is moved from the outside of the measuring space 12 to the injection hole with the tip opening surface 11a of the injection hole 11 and the opening surface 17c of the injection hole 17b being separated from each other. 11 is moved forward in the horizontal direction, the tip opening surfaces 16e of the internal flow paths 16c and 16d of the extrusion nozzle 16a and the tip opening surface 11a of the injection hole 11 are brought into contact with each other, and the internal flow of these extrusion nozzles 16a The paths 16c and 16d and the injection hole 11 are communicated (FIG. 1).

  Next, the molding material is supplied to the measurement space 12 from the extruder 16 through the extrusion nozzle 16 a and the injection hole 11 in this order. At this time, by the flow pressure of the molding material acting on the outer peripheral surfaces of the tapered portion 19 and the inclined portion 21 of the plunger 14, the volume of the measuring space 12 is increased while the plunger 14 is moved backward with respect to the injection hole 11, The measuring space 12 is filled with a molding material. Thus, in the process of filling the molding material, the upper mold 17d is moved forward toward the back surface of the runner member 17f to form the runner 17k, and the lower mold 17b is moved forward toward the back surface of the upper mold 17d. A cavity 17a is formed (FIG. 2).

  Then, the extruder 16 is moved backward in the horizontal direction with respect to the injection hole 11 to release the communication state between the extrusion nozzle 16a and the injection hole 11, and the interior of the extruder 16 and the measuring space 12 are separated from each other. While making it independent, the injection hole 11 is opened downward in the vertical direction. Thereafter, the injection molding machine 10 is moved forward toward the opening surface 17c of the injection hole 17b, that is, the upper end surface of the injection nozzle 17i, and the tip opening surface 11a of the injection hole 11 and the opening surface 17c of the injection hole 17b are brought into contact with each other. These injection holes 11 and injection holes 17b are communicated with each other (FIG. 3).

Next, the plunger 14 is moved forward toward the injection hole 11, and the molding material in the space 12 is injected from the injection hole 11 while gradually decreasing the volume of the metering space 12. The passage 17h and the runner 17k are passed in this order to fill the cavity 17a. Here, when the molding material passes through the injection hole 17b from the injection hole 11 and passes through the injection flow path 17h, the flow passage cross-sectional area is narrowed by the throttle portion 32, and shearing force acts to self-heat. , Its fluidity is further enhanced. When the plunger 14 reaches the forward end position, the tapered portion 19 and the inclined portion 21 are fitted to the one end side portion 22 of the measuring space 12 with the tip 18 of the plunger 14 fitted to the injection hole 11. And the clearance gap between each outer peripheral surface of the taper part 19 and the inclination part 21 of the plunger 14 and the inner wall face of the said one end side part 22 of the measurement space 12 is lose | eliminated substantially (FIG. 4).
Thereafter, the molding material is heated and vulcanized in the cavity 17a for a predetermined time, and then the mold 17 is opened to take out the vulcanized molded product. During the vulcanization or after the injection of the molding material into the cavity 17a is completed, the injection molding machine 10 is moved backward with respect to the injection hole 17b before the vulcanization.

 As described above, according to the injection molding machine 10 according to the present embodiment, the extruder 16 is moved to the injection hole 11 with the tip opening surface 11a of the injection hole 11 and the opening surface 17c of the injection hole 17b separated from each other. When moving forward, the internal flow paths 16c, 16d of the extrusion nozzle 16a and the injection hole 11 communicate with each other, and the molding material is filled from the extrusion nozzle 16a into the measurement space 12 through the injection hole 11. Therefore, as in the present embodiment, even if one end of the measuring space 12 is constituted by the injection hole 11 and the injection passage connecting the one end of the measuring space 12 and the injection hole 11 is not formed in the cylinder 13, the extrusion is performed. When the molding material is supplied from the nozzle 16 a to the measuring space 12, it is possible to prevent the molding material from leaking from the injection hole 11.

  Furthermore, since the extruder 16 is provided so as to be able to advance and retreat toward the injection hole 11 outside the cylinder 13, when the molding material is injected from the injection hole 11, the extruder 16 moves backward from the injection hole 11. Thus, the inside of the extruder 16 can be separated from the measuring space 12 and independent from each other. Therefore, unlike the conventional injection molding machine, there is no need to provide check valves in the internal flow paths 16c and 16d of the extrusion nozzle 16a. Therefore, heat is radiated from the check valves and the molding material in the measuring space 12 is discharged. It is possible to prevent the temperature distribution from occurring. This makes it possible to reliably shorten the vulcanization molding cycle and prevent variations in product quality.

Moreover, in the said embodiment, the extruder 16 is provided so that a slide movement is possible in the direction which cross | intersects the opening direction of the injection hole 11, and the opening direction of the internal flow paths 16c and 16d of the extrusion nozzle 16a is an injection hole. 11 is bent so as to be opposite to the opening direction, the injection molding machine 10 having the above-described effects can be easily and reliably realized.
Furthermore, in this embodiment, since the injection path which connects the one end of the measurement space 12 and the injection hole 11 is not formed in the cylinder 13, the molding material which stays between the injection hole 11 and one end of the measurement space 12 is used. It can be surely reduced.

Further, since the throttle portion 32 is provided in the injection flow path 17h formed in the mold 17, the injection passage 11 and one end of the measurement space 12 are formed without forming the injection passage in the cylinder 13 as described above. Although it is possible to reduce the molding material staying between the mold 17 and the injection hole of the mold 17 even if the temperature rise due to self-heating of the molding material on the cylinder 13 side becomes insufficient at the time of injection. When the molding material injected from 17b passes through the throttle portion 32, the temperature can be sufficiently raised. This makes it possible to reduce the staying molding material as described above, but the molding material becomes low temperature, making it difficult to shorten the vulcanization time, or in the cavity 17a over the entire region. It is possible to prevent occurrence of molding defects such as difficulty in spreading the molding material evenly.
Further, since the throttle portion 32 is formed not in the cylinder 13 but in the injection flow path 17h on the mold 17, the molding material is supplied when the molding material is supplied from the extrusion nozzle 16a into the measuring space 12 through the injection hole 11. However, it is possible to prevent the occurrence of burning due to excessive temperature rise due to self-heating.

  In the present embodiment, in the locate ring 17g, a gap is provided between the outer peripheral surface of the large diameter portion of the injection nozzle 17i and the inner peripheral surface of the counterbore hole formed in the surface of the main body portion 17j. Even when the molding material is not injected into the injection hole 17b and adhered to the opening surface 17c of the injection hole 17b at the time of injection, the tip opening surface 11a of the injection hole 11 and the opening surface of the injection hole 17b are injected at the next injection. It is possible to store the adhering molding material in the gap when it is brought into contact with 17c.

 Furthermore, in this embodiment, when the plunger 14 reaches the forward end position, the tapered portion 19 and the inclined portion 21 are in the one end side portion 22 of the measuring space 12 with the tip 18 fitted into the injection hole 11. So that the gap between the outer peripheral surface of the tapered portion 19 and the inclined portion 21 and the inner wall surface of the one end side portion 22 of the measuring space 12 is reached in a state where the plunger 14 has reached the forward end position. It becomes possible to eliminate substantially and it can also suppress that a molding material retains in this measurement space 12. FIG.

 Therefore, in the next vulcanization molding step, almost all of the molding material filled in the metering space 12 becomes a plasticized molding material for the first time in the extruder 16, so that the metering space 12 is filled. It is possible to make the vulcanization start temperature of the molding material substantially uniform as a whole, and even if the heating temperature of the molding material in the measuring space 12 is set high, the occurrence of burning in the molding material is suppressed. be able to. Thereby, it becomes possible to shorten the vulcanization molding cycle by setting the heating temperature of the molding material in the measurement space 12 high, and to improve the mass productivity.

  Moreover, since the plunger 14 has a configuration in which the tapered portion 19 and the base end portion 20 are connected via the inclined portion 21, the plunger 14 is moved forward, and the molding material in the measuring space 12 is injected into the injection hole 11. In the process of flowing toward the surface, a large shearing force or compressive force is applied to the molding material between the outer peripheral surface of the inclined portion 21 and the inner wall surface of the one end side portion 22 of the measurement space 12, Heat generation of the molding material and flow toward the injection hole 11 can be promoted, and the amount of the molding material remaining in the measurement space 12 can be reliably reduced.

In the present embodiment, the connecting portion between the base end portion 20 and the inclined portion 21, that is, the tip end 20 a of the base end portion 20 is formed in a curved shape that protrudes radially outward of the plunger 14. In the state where the plunger 14 has reached the forward end position, it is possible to prevent the molding material from staying between the connecting portion and the inner wall surface of the measuring space 12 to cause burning.
Furthermore, since the tip end 18 of the plunger 14 is formed in a curved surface that is convex toward the injection hole 11, when the plunger 14 reaches the forward end position and the tip end 18 is fitted into the injection hole 11. In addition, it is possible to prevent the tip 18 and the inner peripheral surface of the injection hole 11 from being damaged by being applied.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, instead of the first and second heating means 30 and 31 of the above embodiment, a configuration in which an electric heater or the like is embedded in the cylinder 13 or the like may be employed.
In the above-described embodiment, the locating ring 17g is constituted by two members including the main body portion 17j and the injection nozzle 17i, but these may be integrally formed instead.
Furthermore, instead of the throttle portion 32 of the above-described embodiment, for example, the inner diameter of the injection flow path 17h is gradually reduced from the injection hole 17b toward the throttle portion, and further gradually increased from the throttle portion toward the runner 17k. You may employ | adopt the aperture | diaphragm | squeeze part which makes it carry out.

  Further, as the inclined portion 21 of the plunger 14, a configuration having an outer peripheral surface extending linearly obliquely downward toward the distal end 18 in the longitudinal sectional view of the plunger 14 has been shown, but instead of this, for example, this plunger 14 may be formed in a curved shape that is recessed inwardly in the radial direction, or may be formed in a curved shape that is convex outward in the radial direction. Furthermore, the inclined portion 21 may not be provided. Further, in the embodiment shown in FIGS. 1 to 4, the outer peripheral surface of the tapered portion 19 may be a straight surface extending along the direction of the central axis O.

  Further, when the plunger 14 reaches the forward end position, the tip 18 is positioned radially inwardly at the opening edge of the injection hole 11 without projecting below the injection hole 11, and the tip opening is opened. However, instead of this, for example, when the plunger 14 reaches the forward end position, the tip end 18 may protrude downward from the injection hole 11.

  Furthermore, in the said embodiment, although the one end of the measurement space 12 was comprised by the injection hole 11, the structure which did not have the injection passage which connects the end of this measurement space 12 and the injection hole 11 was shown, Instead, for example, the present invention can be applied to the cylinder 13 having the injection passage. In this case, the length of the injection passage is desirably 30 mm or less, and more desirably, the inner diameter thereof is greater than or equal to the length. Even in this case, the amount of the molding material staying between one end of the measuring space 12 and the injection hole 11, that is, in the injection passage can be reduced, and the inside of the measuring space 12 from the extrusion nozzle 16 a through the injection hole 11. When the molding material is supplied to the molding material, it is possible to prevent the molding material from being excessively heated by self-heating and burning.

In the above embodiment, the extruder 16 is provided so as to be able to advance and retreat in the horizontal direction from the outside of the measuring space 12 toward the injection hole 11, that is, in the direction orthogonal to the opening direction of the injection hole 11. Any direction may be used as long as it intersects the opening direction of the injection hole 11.
Furthermore, as the internal flow paths 16c and 16d of the extrusion nozzle 16a, the configuration in which the first flow path 16c and the second flow path 16d are orthogonal to each other as described above is shown, but not limited thereto, the internal flow path 16c is not limited thereto. 16d may be bent so that the opening direction is opposite to the opening direction of the injection hole 11.

  While the molding material staying between one end of the metering space and the injection hole can be reduced, it is possible to prevent the molding material from easily leaking from the injection hole when the molding material is supplied into the metering space from the extrusion nozzle. Further, it is possible to prevent the temperature distribution from occurring in the molding material in the measurement space, and to prevent variations in product quality.

It is a partial longitudinal cross-sectional view of the injection molding machine of one Embodiment which concerns on this invention, Comprising: A 1st process drawing is shown. It is a partial longitudinal cross-sectional view of the injection molding machine of one Embodiment which concerns on this invention, Comprising: A 2nd process drawing is shown. It is a partial longitudinal cross-sectional view of the injection molding machine of one Embodiment which concerns on this invention, Comprising: A 3rd process drawing is shown. It is a partial longitudinal cross-sectional view of the injection molding machine of one Embodiment which concerns on this invention, Comprising: A 4th process drawing is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Injection molding machine 11 Injection hole 11a End opening surface of injection hole 12 Measuring space 13 Cylinder 14 Plunger 16 Extruder 16a Extrusion nozzle 16c, 16d Internal flow path 16e End opening surface of internal flow path 17 Mold 17a Cavity 17c Opening surface 17h Injection flow path 32 Restricted part

Claims (4)

A cylinder in which an injection hole is formed at one end and a measuring space communicating with the injection hole is formed inside;
A plunger supported on the other end side of the cylinder so as to be in sliding contact with the inner wall surface of the measuring space;
An extruder for filling the metering space with a molding material in a plasticized state from an extrusion nozzle, and
With the tip opening surface of the injection hole in contact with the opening surface of the injection hole communicating with the cavity formed in the mold, the molding material filled in the measuring space is directed to the injection hole. An injection molding machine that injects from the injection hole and fills the cavity by a forward movement of the plunger,
The extruder is provided so as to be able to advance and retreat toward the injection hole outside the cylinder, and when the tip opening surface of the injection hole and the opening surface of the injection hole are moved forward from each other, the injection is performed. The front end opening surfaces of the holes and the internal flow path of the extrusion nozzle are in contact with each other, the injection holes communicate with the internal flow path, and the molding material is filled from the extrusion nozzle into the measurement space through the injection holes. An injection molding machine characterized by that. An injection molding machine according to claim 1,
The extruder is provided so as to be slidable in a direction intersecting the opening direction of the injection hole,
An injection molding machine, wherein the internal flow path of the extrusion nozzle is bent so that the opening direction is opposite to the opening direction of the injection hole. The injection molding machine according to claim 1 or 2,
An injection molding machine characterized in that an interval between a tip opening surface of the injection hole and one end of the measuring space is 30 mm or less. An injection molding machine according to any one of claims 1 to 3,
An injection molding machine characterized in that an injection flow path for communicating an injection hole and a cavity is formed in the mold, and a throttle portion is provided in the injection flow path.

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