JP2006035686A - Shut-off valve for injection molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the flow resistance due to the shape of a material passage of an injection molding machine to be small, further to deter the leakage to excessive places of a molten material suitably. <P>SOLUTION: A shut-off valve is for an injection molding machine 10, a material passage 12 formed along with the central axis of a body 11 has a nozzle hole 22 at its tip, and the structure for the shut-off valve has: an air cylinder 41 on the straight line of a slanting back which accomplishes a predetermined angle to the central axis of the body 11; a flexible valve pin 35 connected with this air cylinder 41, curving toward the axis of the body 11 from the operation spindle of the air cylinder 41 and attached so that the nozzle hole 22 is closed by the advance limit of the air cylinder 41 and the nozzle hole 22 is opened by the retreat limit to communicate with the material passage 12; and a guide sleeve 31 formed so that the heat release effect is enhanced by the surface area effect of the shape of pleats while guiding the operation of the valve pin 35 between the air cylinder 41 and the body 11. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a shutoff valve for an injection molding machine for resin or light metal.

In general, an injection molding machine is provided with a shut-off valve for mechanically opening and closing a nozzle hole formed at the tip of a cylinder. Specifically, the thing of the structure currently disclosed by the postscript patent document 1 is mentioned, for example. In this disclosure, the nozzle hole is opened and closed by reciprocating the needle valve in the direction of the central axis of the nozzle hole in accordance with the injection timing of the resin. As a result, the so-called “hanata phenomenon” in which the molten material hangs down from the nozzle hole after injection molding can be suppressed. As the drive source of the shutoff valve, the hydraulic pressure is often used when the injection molding machine body is clamped with hydraulic pressure, and the air pressure is often used with an electric molding machine.
JP 2002-370256 A

However, in the above-described conventional technique, the drive portion of the needle valve that operates to open and close the nozzle hole is disposed on the central axis of the nozzle hole, specifically, the position where the material flow path should be originally disposed. As a result, the flow resistance of the molten material is increased, and the malfunction of the needle valve may be caused.
That is, since the diameter of the nozzle hole is usually very small, the needle valve is disposed on the central axis of the nozzle hole so that the tip of the needle valve does not deviate from the nozzle hole. Therefore, the drive portion of the needle valve is also originally disposed at a position (on the central axis of the nozzle hole) that should be a material flow path, and is subjected to heat transfer from around the high temperature state. As a result, the injected molten material leaks through the operating gap of the needle valve in a molten state, and may enter into (or bite into) an extra portion such as the inside of the drive mechanism to cause a malfunction. Furthermore, due to the arrangement configuration described above, the material flow path must be disposed at a position detoured from the position where the needle valve is disposed, which increases flow resistance (pressure loss) due to the shape of the material flow path. .

  The present invention was devised as a solution to the above-mentioned problems, and the problem to be solved by the present invention is to suppress the flow resistance due to the shape of the material flow path of the injection molding machine, and to further melt the material. It is to suppress appropriately the leakage to the unnecessary part.

In order to solve the above problems, the shutoff valve for an injection molding machine of the present invention takes the following means.
That is, the first invention of the present invention is a shutoff valve for an injection molding machine, wherein a material flow path is formed along the central axis of the body, a nozzle hole is formed at the tip thereof, and the central axis of the body is On the straight line diagonally rearward at a predetermined angle, the drive device and the drive device connected to the drive device are curved from the operation shaft of the drive device toward the center axis of the body, and the nozzle hole is closed at the advance limit of the drive device. A flexible valve pin that is mounted to open the nozzle hole and communicate with the material flow path, and the operation of the valve pin between the drive unit and the body, while enhancing the heat dissipation effect by the surface area effect due to the pleated shape And a guide sleeve formed on.
According to the first aspect of the present invention, the tip of the valve pin for opening and closing the nozzle hole is disposed on the central axis of the body. Further, the predetermined portion of the valve pin is curved and disposed on a straight line that is obliquely rearward at a predetermined angle with respect to the central axis of the body due to its flexibility. That is, only the part ahead of the predetermined part from the predetermined part of the valve pin is exposed in the material flow path, and the other part is placed away from the heat source such as the material flow path. Furthermore, the heat conducted through the valve pin or the like is effectively radiated at the position where the guide sleeve having the pleat shape is disposed. The material of the valve pin is preferably spring steel excellent in flexibility (elasticity).

The present invention can obtain the following effects by taking the above-described means.
First, according to the first aspect of the present invention, since the exposure of the valve pin into the material flow path can be suppressed, the flow state of the molten material in the material flow path can be improved. Moreover, since the heat conducted through the valve pin or the like can be effectively dissipated, it is possible to prevent the molten material from leaking to an extra portion such as an operation gap of the valve pin. Therefore, it does not cause malfunction of the drive mechanism.

Embodiments of the best mode for carrying out the present invention will be described below with reference to the drawings.
1 to 4 show an embodiment of a shutoff valve for an injection molding machine according to the present invention. 1 is a cross-sectional view of the main part of the shut-off valve of the present embodiment, FIG. 2 is a plan view of the center guide 25, FIG. 3 is a cross-sectional view taken along the line AA of FIG.
The injection molding machine 10 in the present embodiment is configured such that a nozzle head 21 is screwed to the tip of the body 11 as well shown in FIG. Further, the body 11 of the injection molding machine 10 is provided with a shut-off valve in a state of protruding in a direction inclined radially outward with respect to the central axis (on a straight line obliquely rearward forming a predetermined angle). ing. Specifically, the body 11 has a cylindrical shape composed of a flange portion 11a and a body portion 11b, and a material flow path 12 is formed through the central axis. The former flange portion 11 a is attached to the downstream side of the injection cylinder 17. Moreover, the latter body part 11b is integrally formed in the downstream of the flange part 11a, and the projection part 11c is formed in the one side surface part. The flange portion 11a and the body portion 11b (excluding the portion that interferes with the projection portion 11c) are heated to the melting temperature of the molten material by the band heater 14.
Next, the protruding portion 11 c is disposed so as to protrude in a direction inclined radially outward with respect to the central axis of the body 11. Further, the protrusion 11c is formed with a seating surface 16 for attaching a guide sleeve 31 to be described later at the tip thereof. Furthermore, a penetrating valve pin hole 15 is formed inside the protrusion 11 c and communicates with the material flow path 12.
Next, in the nozzle head 21, the hemispherical shape formed at the tip (convex in the tip direction) is in contact with the concave spherical portion 3 formed on the fixed die 2 of the mold. Here, the mold is attached to the fixed base 1 of the injection molding machine 10. A tapered nozzle hole 22 is formed on the central axis of the nozzle head 21 so that the material flow path 12 is tapered. Therefore, since the material flow path 12 and the flow path formed in the mold are in communication with each other, the molten material injected by the injection molding machine 10 flows from the material flow path 12 into the mold. Filled into the cavity. In addition, a center guide 25 for guiding (core keeping) the position of the tip 35d of the valve pin 35 is inserted in the nozzle head 21. Specifically, the center guide 25 has a shape in which an outer ring 25a and an inner ring 25b are connected by a plurality of ribs 25c, as well shown in FIGS. 2 and 3, and a flow formed between the ribs 25c. The molten material flows in the passage hole 25e. Further, a guide hole 25d formed in the center of the inner ring 25b is adapted to be fitted into the tip part 35d of the valve pin 35, and the position of the tip part 35d is held on the central axis of the nozzle hole 22 ( (Core preservation). As a result, the tip portion 35 d of the valve pin 35 opens and closes with respect to the nozzle hole 22.

Next, as shown in FIG. 1, the guide sleeve 31 is composed of fin portions 31a formed on the peripheral wall surface and tightening portions 31b and 31c formed at both ends. The former fin portion 31a has a pleated shape having an outer diameter (circumferential wall surface) in which a large diameter portion and a small diameter portion are alternately repeated in a bellows shape. Therefore, the surface area effect effectively radiates and cools the conducted heat. In addition, a sliding hole 32 is formed in the guide sleeve 31 in which an intermediate portion 35b of the valve pin 35 is slidably inserted. Specifically, the sliding hole 32 is set to be slightly larger than the outer diameter of the intermediate portion 35b, and a slight clearance is formed between them for easy sliding. The latter tightening portions 31 b and 31 c have one end side portion (tightening portion 31 b) screwed to the seat surface 16, and the other end side portion (tightening portion 31 c) screwed to the cylinder bracket 43. Yes. Specifically, the other end portion is fastened to the cylinder bracket 43 in a state in which it is prevented from being loosened by the lock plate 44.
Therefore, the heat conducted from the heat source such as the body 11 and the body 11b is conducted to the guide sleeve 31 through the protrusion 11c and the valve pin 35 which are integrated with or in contact with them. However, the conducted heat is effectively radiated from the pleated surface formed on the fin portion 31a. Therefore, for example, even when a molten material enters the sliding hole 32 from the material flow path 12, they are cooled and solidified by the heat radiation of the pleat shape, so that they do not leak beyond the guide sleeve 31. .

By the way, the shut-off valve is operated with the air pressure supplied from the air cylinder 41 as a drive source. Note that the air cylinder 41 may be a hydraulic cylinder or an electromagnet instead of this. Here, the air cylinder 41 corresponds to the driving device of the present invention. Specifically, the air cylinder 41 is held on the extension line of the guide sleeve 31 via the cylinder bracket 43. More specifically, the air cylinder 41 is configured to reciprocate the piston 45 at a position between the forward limit and the reverse limit when air is supplied from the air supply port 42 by opening / closing operation of a solenoid valve (not shown). Has been. Further, a holder 47 that supports a flange portion 35 a (see FIG. 4) of the valve pin 35 is connected to the tip of the piston 45 by a connection bolt 46. A space for reciprocating the holder 47 is formed in the cylinder bracket 43. Therefore, the valve pin 35 reciprocates between strokes in the space of the cylinder bracket 43 in conjunction with the piston 45 reciprocating.
The cylinder bracket 43 is formed in a pleat shape in the same manner as the guide sleeve 31 in its outer diameter, and has a configuration in which the heat dissipation effect is enhanced.

Next, the valve pin 35 is comprised by the collar part 35a, the intermediate part 35b, the flexible part 35c, and the front-end | tip part 35d, as FIG. 4 shows well. Here, the valve pin 35 may be one in which the respective parts are integrally formed by integral molding, or may be one in which the parts formed separately are connected by welding or screwing.
Specifically, the brim portion 35 a is connected to the piston 45 of the air cylinder 41 by the holder 47 described above. The intermediate portion 35 b is slidably disposed in the sliding hole 32 of the guide sleeve 31. Further, the front end portion 35 d is fitted (guided) into the guide hole 25 d of the center guide 25, and is disposed toward the central axis direction of the body 11. The flexible portion 35c is curvedly arranged from the arrangement direction of the guide sleeve 31 (the operation axis direction of the intermediate portion 35b) toward the tip portion 35d, and is linked to the reciprocating motion of the piston 45. The portion 35d acts so as to be inserted into and removed from the nozzle hole 22 (open / close operation). Thereby, the front-end | tip part 35d act | operates so that the nozzle hole 22 may be closed with the piston 45 in a forward limit state, and the nozzle hole 22 may be opened in a backward limit state.
That is, the valve pin 35 is configured such that only the flexible portion 35 c and the tip portion 35 d are exposed in the material flow channel 12 in the vicinity of the tip side of the material flow channel 12.

Then, the usage method of the shutoff valve | bulb of a present Example is demonstrated.
First, in a state where the piston 45 of the air cylinder 41 is set to the retreat limit and the nozzle hole 22 is opened, the screw 18 of the injection molding machine 10 is advanced in the injection cylinder 17 to inject a predetermined amount of molten material. Then, the injected molten material flows through the material channel 12 and the channel hole 25e of the center guide 25, is injected from the nozzle hole 22, and is filled in the cavity of the mold.
At this time, the molten material flowing in the material flow path 12 can enter a slight clearance (not shown) between the sliding hole 32 of the guide sleeve 31 and the intermediate portion 35b of the valve pin 35 by the injection pressure. is there. However, as the molten material that has entered enters the clearance toward the air cylinder 41 through the clearance, the molten material gradually separates from the heat source. Further, when flowing in the fin portion 31a of the guide sleeve 31, it is cooled by the heat dissipation effect. Therefore, since the molten material that has entered the clearance is cooled and solidified in the guide sleeve 31, the solidified portion serves as a seal and is prevented from leaking to an unnecessary place.
Next, when the piston 45 of the air cylinder 41 is set to the forward limit after the injection is completed, the valve pin 35 is pushed out in conjunction with this, and the distal end portion 35d moves along the guide hole 25d of the center guide 25 to move the nozzle hole. 22 is closed. At this time, the flexible portion 35c of the valve pin 35 operates smoothly even in a curved state due to its flexibility (elasticity). Therefore, since the nozzle hole 22 is preferably closed by the tip portion 35d of the valve pin 35, the melted material in the material flow path 12 does not leak from the nozzle hole 22 to cause a so-called snare phenomenon.

Thus, according to the shut-off valve of the present embodiment, the valve pin 35 for opening and closing the nozzle hole 22 of the injection molding machine 10 is configured to be exposed only in the vicinity of the front end side of the material flow path 12. Further, a mechanism portion (the guide sleeve 31, the cylinder bracket 43, the air cylinder 41, etc.) for operating the valve pin 35 is disposed at a position separated from the material flow path 12. Furthermore, the molten material that has entered the inside can be effectively cooled and solidified by the guide sleeve 31 constituting the above-described mechanism portion. Accordingly, it is possible to suitably suppress leakage of the molten material to an extra portion while designing the flow resistance (pressure loss) in the material flow path 12 as much as possible.
Further, since the tip 35d of the valve pin 35 is guided (core-maintained) so as to move along the guide hole 25d of the center guide 25, the taper angle of the nozzle hole 22 is not restricted. The tip 35d can be stably fitted into the nozzle hole 22.

It is principal part sectional drawing of the shutoff valve | bulb of a present Example. It is a top view of a center guide. It is the sectional view on the AA line of FIG. It is a front view of a valve pin.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fixed base plate 2 Fixed mold | type 3 Concave spherical surface part 10 Injection molding machine 11 Body 11a Flange part 11b Body part 11c Protrusion part 12 Material flow path 14 Band heater 15 Valve pin hole 16 Seat surface 17 Injection cylinder 18 Screw 21 Nozzle head 22 Nozzle Hole 25 Center guide 25a Outer ring 25b Inner ring 25c Rib 25d Guide hole 25e Channel hole 31 Guide sleeve 31a Fin part 31b, 31c Tightening part 32 Sliding hole 35 Valve pin 35a Collar part 35b Intermediate part 35c Flexible part 35d Tip part 41 Air Cylinder (drive device)
42 Air supply port 43 Cylinder bracket 44 Lock plate 45 Piston 46 Connection bolt 47 Holder

Claims (1)

A shut-off valve for an injection molding machine,
A material flow path is formed along the center axis of the body, a nozzle hole is formed at the tip thereof, and a drive device and a drive device are arranged on a diagonally straight line that forms a predetermined angle with respect to the center axis of the body. It is connected and curved so as to be curved from the operating shaft of the drive device toward the central axis of the body, so that the nozzle hole is closed at the forward limit of the drive device and the nozzle hole is opened at the backward limit to communicate with the material flow path. A shutoff for an injection molding machine comprising: a flexible valve pin; and a guide sleeve formed to enhance the heat dissipation effect by a surface area effect due to a pleat shape while guiding the operation of the valve pin between the driving device and the body valve.

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