JP3053577B2 - 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 portion protruding from the tip of an injection cylinder, and a spool is inserted into the gate so as to be able to move forward and backward, and the spring is constantly pressed in the shirt-off direction. A shut-off nozzle in which a 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 path is opened by moving the flow groove provided on the rear side of the spool to the front of the gate by moving the spool forward by a molding material pressure stronger than the spring pressure. The flow path is not opened unless at least the front end of the flow groove passes through the gate and opens to the nozzle hole side, and the flow path is kept open until the front end of the flow groove fits inside the gate even when shut off. is there. For this reason, the conventional nozzle that shuts off by changing the position of the flow groove on the rear side of the spool lacks the quickness of opening and closing the flow path and is not suitable for molding products that require molding accuracy. Problems.

The present invention has been conceived in order to solve the above-mentioned conventional problems, and an object thereof is to perform shut-off in a nozzle portion by press-contact between a rear inclined surface of a rear portion of a valve head and an opening edge of a valve seat. Accordingly, it is an object of the present invention to provide a new shut-off nozzle of an injection device which has an excellent responsiveness in which a flow path opening operation can be speeded up and a flow path can be immediately opened even by a slight advance movement of a valve member. .

[0005]

SUMMARY OF THE INVENTION According to the present invention, there is provided an annular valve seat provided in a nozzle portion protruding from a tip of an injection cylinder, and a valve member is inserted through the valve seat so as to be able to advance and retreat. In a shut-off nozzle provided with a spring member that constantly presses the valve member in the shut-off direction across the valve seat and the valve member, a valve stem having the valve member having an outer diameter smaller than the inner diameter of the valve seat and penetrating the valve seat. A valve head connected to the front end of the valve stem, the outer diameter of which is larger than the inner diameter of the valve seat, and the rear portion is formed in a truncated conical shape by expanding the diameter; and a spring receiving member attached to the rear end of the valve stem. And the spring member is disposed over the spring receiving member and the valve seat. Becomes pressed against the inclined rear face of the head,
That is.

[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 part 2 is composed of a valve cylinder 3 protruding from the tip of the injection cylinder and a nozzle tip 4 having a rear end opening screwed to the valve cylinder 3. The tip of the valve cylinder 3 covered with the nozzle tip 4 To
A thick, annular valve seat 5 is provided so as to be sandwiched by the nozzle tip 4.

A valve member 6 has a valve stem 7 whose outer diameter is smaller than the inner diameter of the opening 5a of the valve seat 5;
A valve head 8 connected to the tip of the valve stem 7
And a spring receiving member 9 attached to the rear end of the valve stem. The spring receiving member 9 is partially notched so that the molding material flows therethrough. In addition, a plurality of guide pieces 1 that fit into the opening 5a of the valve seat 5 are provided outside the front part of the valve stem 7.
0 protrudes long in the axial direction.

The outer diameter of the valve head 8 is larger than the inner diameter of the opening 5a of the valve seat 5 by enlarging the diameter, and the rear portion 8a is formed in a truncated cone shape, and the front portion 8b is formed in a flat conical shape so as to be square. It has a shape provided with a flow groove 11.

In such a valve member 6, a coiled spring member 12 is loosely fitted around the valve stem 7 inserted through the valve seat 5, and the spring member 12 is screwed to the rear end of the valve stem. It is compressed by the member 9 between the valve stems, and can be attached to the valve cylinder 3 in a state where the inclined rear surface of the valve head 8 is pressed against the peripheral edge of the opening on the nozzle hole side of the valve seat 5.

[0010] Mounting is performed simply by inserting the valve stem 7 side into the valve cylinder 3 and abutting the valve seat 5 against the distal end surface of the valve cylinder 3, screwing the nozzle tip 4 and clamping the valve seat 5. obtain. Also, the nozzle tip 4 is screwed into the nozzle portion 2 so that the inside of the nozzle portion 2 becomes a valve seat 5.
Thereby, a front chamber on the nozzle hole 13 side and a rear chamber on the valve cylinder 3 side are partitioned, and the valve head 8 is housed in the front chamber so as to be able to advance and retreat.

In the above-described configuration, a molding material pressure in a molten state, for example, a resin pressure is applied to the valve member 6 by the advancement of the injection screw 14 in the injection cylinder 1, and the resin member pressure compresses the spring member 12 to cause the valve member 6 to move. Upon forward movement, the rear surface of the valve head 8 is immediately separated from the peripheral edge of the opening of the valve seat 5 to immediately open the flow path, and the resin flows out of the nozzle hole 13 through the front chamber through the opening 5a. When the injection screw 14 stops and the resin pressure drops below the pressure of the compressed spring member 12, the valve member 6 immediately moves backward, and the inclined rear surface of the valve head 8 is pressed against the opening edge of the valve seat 5 and the nozzle off. And cut off the flow of resin.

In view of the above, in the configuration in which the inclined rear surface of the valve head 8 is pressed against the peripheral edge of the opening on the nozzle hole 13 side of the valve seat 5 to perform the nozzle shut, the inner peripheral surface of the gate in the nozzle portion and the front portion of the spool are provided. The nozzle is shut by the surface contact with the outer peripheral surface, and the opening / closing operation of the flow path is faster than the conventional structure in which the valve is opened by moving the position of the flow groove on the rear side of the spool. Since the nozzle is turned off according to the amount of movement and injection of the molding material is started, the response is good, and the valve seat 5 and the valve member 6
Also, since the spring member 12 can be unitized in advance and can be mounted on the nozzle portion 2, there is also an advantage that the assembly is easy.

[Brief description of the drawings]

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

FIG. 2 is a vertical cross-sectional side view similarly showing a flow path open state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Injection cylinder 2 Nozzle part 3 Valve cylinder 5 Valve seat 5a Opening 6 Valve member 7 Valve stem 8 Valve head 8a Rear part 9 Spring receiving member 12 Spring member

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-88896 (JP, A) JP-A-58-92544 (JP, A) JP-A-56-60238 (JP, A) JP-A 61-88 290021 (JP, A) JP-A-10-44194 (JP, A) JP-A-10-44193 (JP, A) JP-A-10-44192 (JP, A) JP-A-55-146723 (JP, A) JP-A-55-15829 (JP, A) JP-A-61-17717 (JP, U) JP-A-57-83826 (JP, U) JP-A-59-148320 (JP, U) JP-A-55-113219 (JP, U) Japanese Utility Model Application Hei 6-68810 (JP, U) Japanese Utility Model Application Publication 55-13084 (JP, U) Registered Utility Model 3022433 (JP, U) US Patent 5356281 (US, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B29C 45/00-45/24

Claims (1)

(57) [Claims] An annular valve seat is provided in a nozzle portion protruding from a tip of an injection cylinder, and a valve member is inserted through the valve seat so as to be able to advance and retreat, and a spring that constantly presses the valve member in a shut-off direction. In a shut-off nozzle in which a member is provided over a valve seat and a valve member, the valve member is connected to a valve stem having an outer diameter smaller than the inner diameter of the valve seat and penetrating the valve seat, and a tip of the valve stem. A valve head having an outer diameter larger than the inner diameter of the valve seat, and a rear portion formed in a truncated cone shape, and a spring receiving member attached to the rear end of the valve stem. The above-mentioned spring member is disposed over the valve seat, and the inclined rear surface of the valve head is pressed against the peripheral edge of the opening on the nozzle hole side of the valve seat. Shut-off nozzle of an injection device according to symptoms.