JP3014971U - Injection machine injection machine - Google Patents

Abstract

(57) [Summary] [Purpose] Proposal of a mechanism in which resin does not stay in the injection device of a pre-plastic injection molding machine, there is no defect in the molded product, and color change is good. [Composition] A resin injection port is provided in the rear, and an inner diameter behind the resin injection port is a small-diameter resin seal part, and an inner diameter in front of the injection port is a large-diameter resin reservoir. A throttle part that is movably inserted and that is open between the outer circumference of the injection plunger and the inner circumference of the injection cylinder is provided near the resin injection port, and the inner circumference of the injection cylinder of the throttle part is eccentric in the direction away from the resin injection port. .

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an injection molding machine (referred to as a prepreg type injection molding machine) having a structure in which a pre-plasticizing device and an injection device are separately provided.

[0002]

[Prior art]

 FIG. 3 shows an injection device 1 using a conventional injection plunger. An injection plunger 26 is provided so as to be capable of reciprocating while being fitted to the inner wall of the injection cylinder 4. The injection cylinder 4 is provided with a plasticizing resin injection port 8 near the tip near the nozzle 9. The tip of the pre-plasticizing device 2 is connected to a bracket 11 provided at the inlet 8. A screw 5 is fitted into the heating cylinder 12 of the preliminary plasticizing device 2 so as to be rotatable and slightly reciprocable. The tip portion of the screw 5 has a large diameter 6 and the heating cylinder 12 also has a space for enclosing the large diameter portion 6. The neck portion of the large-diameter portion 6 of the screw 5 forms a taper 7, and when it is slightly retracted and pressed against the heating cylinder 12, backflow of the resin can be prevented.

The resin plasticized by the pre-plasticizing device 2 is supplied from the plasticizing resin injection port 8 to the injection device 1, and the resin is retracted while the resin is accumulated in the resin reservoir 10. When the resin accumulated in the resin reservoir 10 has accumulated up to a specified amount, the screw 5 in the pre-plasticizing device 2 retracts as described above, the taper portion 7 comes into contact with it to prevent backflow, and the injection plunger 26 Is advanced to inject the resin.

[0004]

[Problems to be solved by the device]

 Considering the filling state of the resin in the process in which the resin plasticized by the pre-plasticizing device 2 is supplied into the resin reservoir 10 of the injection cylinder 4 and the injection plunger 26 retracts, the first injected resin is the resin injected into the injection plunger 26. Located at the tip 13, the injection plunger 26 is pushed and both retract, and the vicinity of the injection port 8 is filled with the resin supplied later. During the backward movement of the injection plunger 26, the resin always accumulates in this state, and new resin always occupies the vicinity of the nozzle 9.

It is a known fact that when this is injected, the molten resin at the tip 13 peels off and is difficult to inject into the mold, and the resin that has deteriorated and carbonized due to the heat received from the injection cylinder 4 during retention It has been often pointed out that small amounts of slag are peeled off and mixed into the molded product, resulting in poor appearance of the molded product, insufficient strength, and defective resin replacement.

[0006]

[Means for Solving the Problems]

 In order to promote the first-in first-out of the resin to be supplied into the injection cylinder 4, the injection port 8 is moved to the rear of the nozzle 9 (in the right-hand direction in the figure) so that the injected resin is sequentially accumulated from near the nozzle 9 to the rear. . For this purpose, the injection cylinder 4 has an inner diameter rearward of the pouring port 8 moved to the rear side smaller than the inner diameter of the resin reservoir 10, and the injection plunger 26 is thin so as to fit into the small diameter.

[0007]

[Action]

 The resin supplied from the rear injection port moves in the direction of the nozzle through the gap between the outer diameter of the injection plunger and the inner diameter of the injection cylinder, and accumulates in order from the vicinity of the nozzle. At the end of accumulation, the resin located near the injection port is always the last resin supplied, and the resin is replaced every cycle.

[0008]

【Example】

 FIG. 1 shows a pre-plastic injection molding machine comprising the injection device of the present invention. FIG. 2 is a detailed view around the injection port 27 of the plasticizing resin of the injection device 3. The injection device 3 has a nozzle 9 at the tip, a plasticizing resin injection port 27 is arranged rearward, and an injection cylinder 14 having a resin seal portion 23 having a diameter smaller than the inner diameter of the resin reservoir 10 is attached to the inner diameter of the resin seal portion 23. The ejection plunger 15 is reciprocally inserted in the. The hydraulic cylinder 16 connected to the rear end of the injection plunger 15 drives the injection plunger 15.

The tip of the heating cylinder 12 is connected to the injection port 27 of the plasticizing device 3, and the screw 5 having the large-diameter portion 6 and the taper 7 on the neck is rotatable and slightly reciprocable in the heating cylinder 12. Has been inserted into. The heating cylinder 12 has a space portion that encloses the large diameter portion 6 of the screw 5. The rear end of the screw 5 is connected to an oil motor 21 via a bearing box 20 which receives a thrust force from the screw 5 and holds it in a rotatable manner. Both sides 24 of the bearing box 20 are connected to hydraulic cylinders 19, 19. At the time of injection, this hydraulic cylinder 19 is driven to retract the screw 5 and press the taper 7 against the heating cylinder 12 to prevent the resin from flowing backward.

In FIG. 2, a gap 25 is formed between the injection cylinder 14 and the injection plunger 15 and serves as a resin passage. Reference numeral 17 denotes an annular throttle portion which is formed by the outer circumference of the injection plunger 15 provided in the resin passage 25. In the state where the annular gap is evenly opened to the outer circumference of the injection plunger 15, the resin supplied from the injection port 27 bends at a right angle and moves to the resin pool 10 direction, and the position closest to the injection port 27. However, the passage resistance is the smallest, and you will concentrate here. At point D, which is farthest from the injection port 27, the amount of resin passing through is extremely small. Therefore, the resin may stay at point D. A diaphragm 17 is provided to eliminate these disadvantages.

In order to increase the amount of resin passing through the point D of the throttle portion 17, the inner diameter of the throttle portion 17 on the injection cylinder 14 side is eccentric to the axial center in the direction away from the injection port 27, and the A-A disconnection is performed. In the plan view, the gap at point B is made narrower and the gap at point C is made wider so that the resin passes uniformly around the circumference of the injection plunger and the resin does not stay at point D. Reference numeral 18 denotes a relief of a machining tool provided on the axis, but forms a passage for wrapping around the resin supplied from the injection port 27 toward the point D side. At the point D, it is necessary to be careful not to make a large step with the diaphragm 17 and to connect to the diaphragm 17 with a gentle curve.

[0012]

[Effect of device]

 Since the injection port 27 of the plasticizing resin is moved to the rear of the injection cylinder 14, the resin in the resin reservoir 10 is always replaced, there is no stagnation, and the defects of the molded product due to the deterioration of the resin are reduced, and the resin can be easily replaced. Now you can do it. Further, the narrowed portion 17 is provided to prevent the accumulation of the resin which is likely to occur at the point D.

[Brief description of drawings]

FIG. 1 is an injection molding machine using the injection device of the invention.

[Fig. 2] Detailed view of the vicinity of the inlet

FIG. 3 Conventional injection molding machine

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Injection device 2 Preliminary plasticizing device 3 Injection device 5 Screw 6 Large diameter part 7 Taper 8 Injection port 10 Resin reservoir 12 Heating cylinder 13 Tip 14 Injection cylinder 15 Injection plunger 17 Throttling part 23 Resin sealing part 25 Resin passage

Claims (1)

[Scope of utility model registration request] 1. A supply of molten resin from a pre-plasticizing device (2), the resin being once accumulated in a resin reservoir (10),
The injection plunger (1
5) In the injection device (3) of the pre-plastic injection molding machine for advancing by injecting 5), the injection port (27) is provided at the rear side, and the resin seal part (23) at the rear side of the injection port (27) is provided. The injection plunger (15) is inserted into the resin seal portion (23) of the injection cylinder (14) having an inner diameter smaller than the inner diameter of the resin reservoir (10) in front of the injection port (27), and the injection port (15 Proximity to 27),
Annular throttle (1) surrounding the injection plunger (15)
The inner diameter of (7) is eccentric to the inlet (27) in the opposite direction, and the throttle portion (1) farthest from the inlet (27) is located.
7) The injection device of the injection molding machine, characterized in that the inner passage is widest.