JPH08156047A - Injection device - Google Patents

Abstract

PURPOSE: To enable a kneading property of a resin to be enhanced and also enable the cost to be reduced by providing a seal ring on a currently used injection device. CONSTITUTION: The device comprises a screw 43, a screw head 31, a nonreturn ring 40, and a seal ring 45 being fixed between the screw 43 and the screw head 31 and acting to seal the screw 43 side and the screw head 31 side as the nonreturn ring 40 moves backward and comes in contact therewith. When the screw 43 is moved rearward while rotating, since the nonreturn ring 40 moves forward, a resin passes through the space between the seal ring 45 and the nonreturn ring 40 so as to finally be stayed in the front part of the screw head 31. The outer peripheral surface of the seal ring 41 has projections 51 formed in a plurality of pieces in the peripheral direction and a plurality of rows in the axial direction. While passing through the seal ring 45, the resin is moved in a serpentine manner among the interstices of the projections 51, hence resin is kneaded preferably.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection device.

[0002]

2. Description of the Related Art Conventionally, in an injection molding machine, a resin which has been heated and melted in a heating cylinder is injected from an injection nozzle to fill a cavity of a mold. Then, a screw is rotatably and reciprocally arranged in the heating cylinder, and when the screw is rotated and retracted, the pellet resin fed from the hopper is melted while being advanced, and kneaded. It is stored and stored in front of the screw.

Subsequently, when the screw is advanced, the resin stored in front of the screw is injected from the injection nozzle and filled in the cavity of the mold. After that, the mold is cooled to solidify the resin, and the mold is opened so that the molded product can be taken out. By the way, although the resin is melted and kneaded in the heating cylinder, it is conceivable to use a mixing nozzle as a highly kneading injection nozzle in order to obtain the resin in a well kneaded state.

However, the mixing nozzle is expensive and the cost is high. Also, since the tip of the mixing nozzle is brought into contact with the mold during injection,
Not only is it necessary to change the shape, dimensions, etc. according to the design of the mold, but also the filling pressure becomes high. further,
Mixing nozzles have many restrictions as compared with general injection nozzles, and their compatibility with dies becomes low.

Therefore, normally, a screw having a high kneading property is used. FIG. 2 is a diagram showing a first example of a conventional screw having a high kneadability, FIG. 3 is a diagram showing a second example of a conventional screw having a high kneadability, and FIG. 4 is a diagram showing a first example of a conventional screw having a high kneadability. 3 is a diagram showing an example of FIG. 3, FIG. 5 is a diagram showing a fourth example of a conventional high kneading screw, and FIG. 6 is a diagram showing a conventional high kneading three-stage screw.
FIG. 7 is an enlarged view of a main part of a conventional three-stage screw having high kneading properties.

In FIG. 2, 11 is a heating cylinder and 12
Is a screw. The screw 12 has flights 13 having a spiral shape, and the groove 1 is provided between the flights 13.
4 is formed. A kneading part 15 is formed at the tip of the screw 12, and the kneading part 15 has a plurality of parallel grooves 16 in the circumferential direction. Therefore, the resin (not shown) moved forward (to the left in the drawing) through the groove 14 as the screw 12 rotates is further stored in front of the screw head (not shown) through the groove 16. The resin is well kneaded while passing through the groove 16.

In FIG. 3, 11 is a heating cylinder and 12
Is a screw. The screw 12 has a spiral flight 13, and a groove 14 is formed between the flights 13. In addition, a kneading section 15 is provided near the tip of the screw 12.
The kneading part 15 has a barrier groove 17 meandering in the circumferential direction. Therefore, the screw 12
The resin (not shown) moved forward (to the left in the figure) through the groove 14 in accordance with the rotation of (1) is further stored in front of the screw head (not shown) through the barrier groove 17. The resin is well kneaded while passing through the barrier groove 17.

In FIG. 4, 11 is a heating cylinder and 12 is a heating cylinder.
Is a screw. The screw 12 has a spiral flight 13, and a groove 14 is formed between the flights 13. In addition, a kneading section 15 is provided near the tip of the screw 12.
Is formed, and the kneading section 15 has a subflight 18 between the flights 13. Therefore, the resin moved forward (to the left in the drawing) through the groove 14 as the screw 12 rotates further moves to the groove 19 between the subflights 18.
It is stored in front of the screw head (not shown). The resin is well kneaded while passing through the groove 19.

In FIG. 5, 11 is a heating cylinder and 12
Is a screw. The screw 12 has a spiral flight 13, and a groove 14 is formed between the flights 13. In addition, a kneading section 15 is provided near the tip of the screw 12.
Are formed, and in the kneading section 15, each flight 13
The screw shaft portion 20 therebetween is eccentric, and the depth of the eccentric groove 21 in the eccentric screw shaft portion 20 is changed. Therefore, the resin (not shown) moved forward (to the left in the drawing) through the groove 14 as the screw 12 rotates further passes through the eccentric groove 21 around the screw shaft portion 20 to the front of the screw head (not shown). Stored in. Then, the resin is well kneaded while passing through the eccentric groove 21.

In FIGS. 6 and 7, 22 is a three-stage screw and 15 is the three-stage screw 22.
It is a kneading part formed in the central part of. In the kneading section 15, inflow grooves 23 having a gradually decreasing depth and outflow grooves 24 having a gradually increasing depth are alternately arranged in the circumferential direction. Therefore, the resin (not shown) moved forward (to the left in the drawing) through the groove (not shown) as the screw 12 rotates further flows from the inflow groove 23 to the outflow groove 24 and moves to the front of the screw head (not shown). It can be stored. The resin is well kneaded while passing through the inflow groove 23 and the outflow groove 24.

[0011]

However, in the conventional injection device described above, not only the amount of resin retained in the kneading section 15 increases, but also color change and resin change cannot be easily performed. Therefore, when handling many types of resin, each time you use an unsuitable resin,
The screws 12, three-stage screws 22, etc. must be replaced. However, the screw 1
Since the 2 and the three stage screw 22 are expensive, the cost is high. Further, the work of replacing the screw 12, the three-stage screw 22, and the like is troublesome.

The present invention solves the problems of the conventional injection device and attaches a seal ring to the existing injection device to improve the kneading property of the resin, reduce the cost, and simplify the work. It is an object of the present invention to provide an injection device that can be manufactured.

[0013]

To this end, in the injection apparatus of the present invention, a screw rotatably and reciprocally arranged in the heating cylinder, and a screw head fixed to the tip of the screw, A non-return ring disposed movably in the axial direction outside the screw head, and fixed between the screw and the screw head, when the non-return ring is abutted by retracting, It has a seal ring for sealing the screw side and the screw head side.

A plurality of protrusions are formed in the circumferential direction and a plurality of rows are formed in the axial direction on the outer peripheral surface of the seal ring.

[0015]

According to the present invention, as described above, in the injection device, the screw rotatably and reciprocally arranged in the heating cylinder, the screw head fixed to the tip of the screw, and the screw A non-return ring arranged axially movably outside the head,
Fixed between the screw and screw head,
The check ring has a seal ring for sealing the screw side and the screw head side when the check ring is retracted and brought into contact with the check ring.

Therefore, when the screw is retracted while rotating, the check ring moves forward, so that the resin passes between the seal ring and the check ring,
It then passes between the check ring and the screw head and is stored in front of the screw head. Then, when the screw is moved forward, the check ring moves rearward and is brought into contact with the seal ring. Therefore, the resin stored in front of the screw head is moved forward as the screw advances and is ejected from the injection nozzle.

Then, on the outer peripheral surface of the seal ring,
A plurality of protrusions are formed in the circumferential direction and a plurality of rows are formed in the axial direction. Therefore, the resin is made to meander in the gap between the protrusions while passing through the seal ring.

[0018]

Embodiments of the present invention will now be described in detail with reference to the drawings. 1 is a sectional view of an injection device according to an embodiment of the present invention, FIG. 8 is a front view showing a first example of a seal ring according to the embodiment of the present invention, and FIG. 9 is a first view of a seal ring according to the embodiment of the present invention. 1 is a side view showing an example of FIG.
0 is a front view showing a second example of the seal ring in the embodiment of the present invention, and FIG. 11 is a side view showing a second example of the seal ring in the embodiment of the present invention.

In the figure, 31 is a screw head, a conical portion 32 at the tip, and a prismatic large diameter portion 3 formed behind the conical portion 32 (to the right in the figure).
3, cylindrical small-diameter portion 3 formed behind the large-diameter portion 33
4, an enlarged diameter portion 35 formed behind the small diameter portion 34, and a screw portion 36 formed behind the enlarged diameter portion 35.
Further, 40 is a cylindrical check ring for preventing backflow of the resin, and is arranged so as to surround the small diameter portion 34, and a resin flow path is provided between the check ring 40 and the small diameter portion 34. 41 is formed.

Reference numeral 43 denotes a screw rotatably and advancingly retracted in a heating cylinder (not shown), and the screw portion 36 is screwed into the opening at the tip. A spiral flight 48 is arranged on the screw 43, and a groove 49 is formed between the flights 48. Reference numeral 45 is a cylindrical seal ring that is fixed by screwing the threaded portion 36 into the opening at the tip of the screw 43. The seal ring 45 has the threaded portion 36.
Has a through hole 53 for penetrating. When the check ring 40 retracts (moves to the right in the figure), the rear end surface 40a of the check ring 40 and the front end surface 45a of the seal ring 45 come into contact with each other, and the screw head 31 side. And the screw 43 side are sealed.

In the injection apparatus having the above construction, when the screw 43 moves forward (moves to the left in the drawing), resin is injected from an injection nozzle (not shown) fixed to the tip of the heating cylinder, and a mold (not shown). Filled in the cavity. Subsequently, the work of melting and plasticizing the resin for the next shot and storing it in front of the screw head 31 (on the left side in the drawing), that is, the measuring process is started.

In this measuring step, the screw 43
Is driven by a drive system (not shown) to move backward, and at this time, the resin supplied from the hopper (not shown) moves forward in the groove 49 by the rotation of the screw 43, is melted in the heating cylinder, and is sealed by the seal ring 45. It is stored in front of the screw head 31 between the heating cylinder and the heating cylinder and through the resin flow path 41. In this case, the pressure of the resin generated by the melting becomes a reaction force to the screw 43, and the reaction force causes the screw 43 to retract.

In this way, the resin stored in front of the screw head 31 is injected from the injection nozzle as the screw 43 is moved forward by the drive system, and is filled in the cavity of the mold. here,
A part of the resin tries to flow backward through the groove 49 due to a reaction force generated as the screw 43 advances. The check ring 40 is disposed at the tip of the screw 43 to prevent the resin from flowing backward. Further, in order to prevent the check ring 40 from coming off the screw 43, the screw head 31 which is a separate body from the screw 43
Is formed, and a screw portion 36 is formed on the screw head 31, and the screw head 31 is screwed into the opening portion at the tip of the screw 43. The outer diameter of the large diameter portion 33 of the screw head 31 is made larger than the inner diameter of the check ring 40 to prevent the check ring 40 from coming off.

By the way, a plurality of projections 51 are formed on the outer peripheral surface of the seal ring 45 so as to project radially outward. As shown in FIGS. 8 and 9, the protrusions 51 are formed in a plurality of rows at equal intervals in the circumferential direction and at equal intervals in the axial direction. Moreover, the protrusions 51 in each row are formed with a pitch shifted from each other, and when seen through in the axial direction, the entire circumferential direction of the seal ring 45 is pseudo-filled by the protrusions 51 in any row. Has become.

Then, when the screw 43 is retracted while rotating, the melted resin passes through the groove 49 and reaches the seal ring 45. The seal ring 45
Since a plurality of rows of a plurality of protrusions 51 are formed on the outer peripheral surface of the resin, the resin reaching the seal ring 45 enters the gap 52 between the protrusions 51 as shown by the arrow in FIG. It collides with the protrusions 51 of the row. Thereafter, the resin further enters the gaps 52 on both sides of the colliding projection 51, and the collision and the entry are repeated. In this way, the resin reaching the seal ring 45 meanders through the gap 52, reaches the screw head 31 side, and is kneaded well during this time.

In the case of handling many kinds of resins, when a resin not suitable for the seal ring 45 is used, the screw head 31 is removed from the screw 43 and the seal ring 45 is replaced with another kind. can do. Therefore, the color change and the resin change can be easily performed. For example, FIGS. 1, 8 and 9
In the case of the seal ring 45 shown in FIG. 5, since the protrusions 51 are formed in five rows, the kneading property is high. On the other hand, in the case of the seal ring 45 shown in FIGS. 10 and 11, since the protrusions 51 are formed in only two rows, the kneading property is low. In this way, the seal ring 45 can be selected according to the required high kneading property.

In this case, since it is not necessary to replace the screw head 31, the check ring 40 and the screw 43, the cost can be reduced. Moreover, since it is not necessary to clean the inner surface of the heating cylinder when the seal ring 45 is replaced, the work can be simplified. It should be noted that the present invention is not limited to the above-described embodiments, and various modifications can be made based on the spirit of the present invention, and they are not excluded from the scope of the present invention.

[0028]

As described in detail above, according to the present invention, in the injection device, the screw disposed rotatably and retractably in the heating cylinder, and the screw fixed to the tip of the screw. A head, a check ring disposed movably in the axial direction outside the screw head, and fixed between the screw and the screw head, and when the check ring retracts and abuts , And a seal ring for sealing the screw side and the screw head side.

Therefore, when the screw is rotated and retracted, the check ring moves forward, so that the resin passes between the seal ring and the check ring.
It then passes between the check ring and the screw head and is stored in front of the screw head. Then, when the screw is moved forward, the check ring moves rearward and is brought into contact with the seal ring. Therefore, the resin stored in front of the screw head is moved forward as the screw advances and is ejected from the injection nozzle.

Then, on the outer peripheral surface of the seal ring,
A plurality of protrusions are formed in the circumferential direction and a plurality of rows are formed in the axial direction. Therefore, the resin is made to meander in the gap between the protrusions while passing through the seal ring, and during this time, the resin is well kneaded. Also, when handling many types of resin, when using a resin that is not suitable for the seal ring, remove the screw head from the screw,
The seal ring can be exchanged for other types. Therefore, the color change and the resin change can be easily performed.

In this case, it is only necessary to replace the seal ring, and it is not necessary to replace the screw head, the check ring, the screw, the three-stage screw, etc., so that the work can be simplified.

[Brief description of drawings]

FIG. 1 is a sectional view of an injection device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a first example of a conventional screw having a high kneading property.

FIG. 3 is a diagram showing a second example of a conventional screw having a high kneading property.

FIG. 4 is a diagram showing a third example of a conventional screw having a high kneading property.

FIG. 5 is a diagram showing a fourth example of a conventional screw having a high kneading property.

FIG. 6 is a view showing a conventional three-stage screw having high kneadability.

FIG. 7 is an enlarged view of a main part of a conventional three-stage screw having high kneading properties.

FIG. 8 is a front view showing a first example of the seal ring according to the embodiment of the invention.

FIG. 9 is a side view showing a first example of the seal ring according to the embodiment of the invention.

FIG. 10 is a second seal ring according to the embodiment of the present invention.
It is a front view which shows the example of.

FIG. 11 is a second seal ring according to the embodiment of the present invention.
It is a side view which shows the example of.

[Explanation of symbols]

 31 screw head 40 check ring 43 screw 45 seal ring 51 protrusion

Claims (1)

[Claims] 1. A screw, which is rotatably and reciprocally disposed in a heating cylinder, and (b) a screw head fixed to the tip of the screw.
(C) A non-return ring disposed axially movably outside the screw head, and (d) fixed between the screw and the screw head, the non-return ring retracts and abuts. And a seal ring for sealing the screw side and the screw head side when they are made to move, and (e) the outer peripheral surface of the seal ring has a plurality of protrusions in the circumferential direction and in the axial direction. An injection device having a plurality of rows.