JP3053578B2 - Injection device shut-off nozzle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shut-off nozzle of an injection device used for molding a synthetic resin or the like containing a molding material such as a synthetic resin and ceramic or powdery metal.

[0002]

A large-diameter gate is provided in a nozzle protruding from the tip of an injection cylinder, and a spool is inserted into the gate so as to be able to advance and retreat, and the spool is constantly pressed in a shut-off direction. A shut-off nozzle in which a spring member is provided between the nozzle portion side and the spool is already known from Japanese Patent Application Laid-Open No. 61-290021.

In such a shut-off nozzle, the flow groove provided on the rear side of the spool is moved to the front of the gate to open the flow path. Therefore, at least the front end of the flow groove passes through the gate and moves toward the nozzle hole. The flow path is not opened unless it is opened, and since the front part of the flow groove is housed in the gate, not only does foreign matter in the molding material enter the gate and hinder the shut-off, There is a problem in that the gate is damaged due to galling caused by foreign matter protruding from the groove.

The present invention has been conceived in order to solve the above-mentioned conventional problems, and has as its object to shut off by surface contact between an inner peripheral surface of an opening of a partition in a nozzle and an outer peripheral surface of a spool head. The object of the present invention is to provide a new shut-off nozzle for an injection device which reduces surface pressure at the time of shut-off, prevents damage due to intrusion of foreign matter, and can withstand long-term use.

[0005]

SUMMARY OF THE INVENTION According to the present invention, an annular partition is provided in a nozzle member protruding from the tip of an injection cylinder, and a spool is provided so as to be able to advance and retreat through the partition. In a shut-off nozzle provided with a spring member that constantly presses the spool in the shut direction over the partition and the spool, the spool is attached to a stem having an outer diameter smaller than the inner diameter of the partition and a rear end of the stem. A spring receiving member, and a cylindrical spool head which is provided at the tip of the stem and whose outer diameter is formed to be the same as the inner diameter of the partition portion by expanding the diameter. The contact member is shut off by contact, and the spring member is provided between the partition portion and the spring receiving member.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the drawing, reference numeral 1 denotes an injection cylinder having a nozzle portion 2 at the tip. The nozzle portion 2 includes a nozzle base 3 protruding from the tip of the injection cylinder, a valve cylinder 4 having a rear end opening screwed to the nozzle base 3, and a nozzle tip 5 having a rear end opening screwed to the valve cylinder front end. The end wall of the valve cylinder 4 which is configured and covered with the nozzle tip 5 is formed in an annular partition 6 in the nozzle portion with an opening 6a provided in the center.

Reference numeral 7 denotes a spool serving as a shut-off valve. The stem 8 has an outer diameter smaller than the inner diameter of the opening 6a of the partition 6, and a spring receiving member 9 attached to the rear end of the stem 8.
And a cylindrical spool head 10 which is connected to the tip of the stem and whose outer diameter is formed by expanding the outer diameter to be the same as the inner diameter of the partition portion 6. The front portion 10 a of the spool head 10
Is formed in a flat conical shape, provided with flow grooves 11 on all sides, and a connecting portion with the stem 8 is formed on an inclined surface. The spring receiving member 9 is partially notched so that the molding material flows.

In such a spool 7, the spool 8 is inserted into the opening 6a of the partition 6 with the stem 8 as the valve cylinder 4 side, and the coil-shaped spring member 12 is loosely fitted around the stem 8. After the spring member 12 can be compressed between the partition 6 and the spring receiving member 9 screwed to the rear end of the stem, the valve cylinder 4 is screwed to the nozzle base 3 so that the inside of the nozzle 2 is Can be provided.

The screw connection of the valve cylinder 4 is performed by contacting a stop ring 13 with the tip end surface of the nozzle base 3.
The stop ring 13 sandwiched and fixed between the nozzle base 3 and the valve cylinder 4 causes the spring receiving member 9 to elastically support the spring receiving member 9 by means of the spring member 12, so that the surface between the inner peripheral surface of the partition 6 and the outer peripheral surface of the spool head 10 is formed. Shut off by contact is maintained.

When the nozzle tip 5 is screwed, the interior of the nozzle 2 is partitioned into a front chamber on the side of the nozzle hole 14 and a rear chamber on the side of the valve cylinder 4 by a partition section 6. Moves forward and escapes from the opening 6a to form a flow path around the stem by the opening 6a.

In the above-described configuration, a molding material pressure in a molten state, for example, a resin pressure is applied to the spool 7 by advancing the injection screw 15 in the injection cylinder 1, and the spring member 1 is moved by the resin pressure.
When the spool 2 is moved forward by compressing the spool 2, the spool head 8 is protruded into the front chamber and comes out of the opening 6a to open the flow path. As a result, the rear chamber communicates with the front chamber, and the resin flows out of the nozzle hole 14 through the front chamber through the opening 6a. When the resin pressure drops below the pressure of the compressed spring member 12 due to the stop of the injection screw 15, the spool 6 immediately retreats, and the spool head 8 is fitted into the opening 6a again to form a nozzle shut, thereby causing the resin to flow. Sever.

As described above, in the configuration in which the shut-off is performed by the surface contact between the inner peripheral surface of the partition portion in the nozzle portion and the outer peripheral surface of the spool head, there is no gap where another object enters the contact portion, so that foreign matter can enter. Imperfect shut-off due to this is prevented, and there is no particular problem even if the molding material is regenerated resin, which often contains foreign matter, and the surface pressure at the time of shut-off is lower than that of the nozzle shut due to the contact surface. Since it can be reduced, there is an advantage that it can sufficiently withstand long-term use.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view showing a closed state of a shut-off nozzle of an injection device according to the present invention.

FIG. 2 is a vertical sectional side view showing the valve opening state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Injection cylinder 2 Nozzle part 4 Valve cylinder 5 Nozzle tip 6 Partition part 6a Opening 7 Spool 8 Stem 9 Spring receiving member 10 Spool head 12 Spring member 13 Stop ring 14 Nozzle hole

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-156203 (JP, A) JP-A-55-77543 (JP, A) JP-A-61-290021 (JP, A) JP-A-10- 44194 (JP, A) JP-A-10-44193 (JP, A) JP-A-10-44191 (JP, A) JP-A-55-146723 (JP, A) Japanese Utility Model Laid-Open No. 61-31717 (JP, U) Japanese Utility Model 1983--17120 (JP, U) Japanese Utility Model 56-3626 (JP, U) Japanese Utility Model 59-148320 (JP, U) Japanese Utility Model 61-37914 (JP, U) Japanese Utility Model 55-13084 (JP, U) Japanese Utility Model Sho 58-112522 (JP, U) Registered utility model 3022433 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 45/00-45/24

Claims (1)

(57) [Claims] An annular partition is provided in a nozzle member protruding from the tip of an injection cylinder, and a spool is provided to penetrate the partition so as to be able to advance and retreat, and a spring that constantly presses the spool in a shut-off direction. In a shut-off nozzle in which a member is provided over a partition and a spool, the spool is connected to a stem having an outer diameter smaller than the inner diameter of the partition, a spring receiving member attached to a rear end of the stem, and a tip of the stem. And a cylindrical spool head whose outer diameter is formed as the inner diameter of the partition by expanding the diameter.
A shut-off nozzle for an injection device, wherein the spool head is fitted into an opening of a partition portion to shut off the surface by surface contact, and the spring member is provided between the partition portion and a spring receiving member.