JPH0512112U - Injection mold - Google Patents

Abstract

(57) [Summary] (Corrected) [Purpose] For injection molding, where the injection pressure can be set low and the molding cycle can be shortened even in the tunnel gate system where the gate opening is provided on the non-designed surface of the molded product. The purpose is to provide a mold. [Composition] Split molds 1 and 2 that are divided into two are provided, and one split mold 1 and 2 is provided with a tunnel gate that communicates with the cavity, and a slide that can be slid to block the gate opening of the cavity. The piece 3 is arranged facing the tunnel gate.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a gateless mold for injection molding, and more particularly to a tunnel gate type injection mold for forming a gate opening on a non-designed surface when the entire surface of a molded product forms a designed surface.

[0002]

[Prior Art]

 In conventional injection molding dies, after the plasticized resin has been injected into the cavity and before the resin in the gate port has solidified, a movable pin is inserted into the gate port to block the gate port. The technique applied to the method is disclosed. (See Japanese Patent Publication No. 5-5338). However, in this method, when the entire circumference of the molded product forms a design surface, the resin at the gate opening is compressed to cause poor appearance and thin burrs. There was a problem that it was likely to occur.

As a means for solving this, a method of providing a gate opening on the non-designed surface of the molded product by using a tunnel gate has been proposed.

[0004]

[Problems to be solved by the device]

 However, in the case of the above tunnel gate, the cross-sectional area of the gate opening of the cavity is usually small, so when injecting plasticized resin, the injection pressure must be set high and a resin with high viscosity must be used. When it is used, injection into the cavity is difficult, which not only puts a load on the molding machine, but also has the drawback of lengthening the molding cycle.

The present invention has been made in view of the above circumstances, and the injection pressure can be set low even in the tunnel gate method in which the gate opening is provided on the non-designed surface of the molded product. It is an object of the present invention to provide a mold for injection molding that can shorten the cycle.

[0006]

[Means for Solving the Problems]

 The injection molding die of the present invention which solves the above-mentioned problems is provided with a split mold which is divided into two, and one of the split molds is provided with a tunnel gate communicating with the cavity, and It is characterized in that a slidable slide piece is arranged facing the tunnel gate to block the communicating gate opening.

[0007]

[Operation and effect of the device]

 In the injection molding die according to the present invention, the plasticized resin is injected into the cavity through the runner, the tunnel gate, and the gate opening when the die is clamped. At that time, the gate opening communicating with the tunnel gate of the cavity has a large step area. Then, after the injection of the resin is completed and before the resin in the gate opening is solidified, the slide piece facing the tunnel gate is slid to block the gate opening. After that, by using the knockout pin for the runner and the knockout pin for the molded product that are provided in the split mold with the tunnel gate, push out the runner and the molded product to cleanly separate the runner and the molded product from the split mold. be able to.

Therefore, the injection mold according to the present invention can increase the step area of the gate port that communicates with the tunnel gate of the cavity when the plasticized resin is injected, so that the injection pressure is low. It can be set, and the plasticized resin can be easily injected into the cavity without imposing a load on the molding machine. Therefore, even if the resin has high viscosity, the injection molding die according to the present invention to which the tunnel gate method is applied can be used.

Further, after the injection of the plasticized resin is completed and before the resin is solidified, the slide piece provided facing the tunnel gate can be slid to block the gate opening. Since there are almost no traces left and the finish is beautiful, there is no need to finish the gate mark on the molded product.

[0010]

Embodiment An embodiment of the present invention will be described below with reference to the drawings. The present embodiment relates to an injection molding die for molding a molded product whose entire circumference forms a design surface.

As shown in FIG. 1, the injection molding die of this embodiment includes two split molds 1 and 2 forming a cavity 11 for molding a molded product T. A runner R for injecting the plasticized resin into the cavity 11 at the time of molding into the cavity 11 through the tunnel gate 12 and the gate port 21 is provided on the mating surface of the split molds 1 and 2. There is. The gate port 21 is provided on the non-designed surface. Further, in the present embodiment, the tunnel gate 12 has a substantially linear gate structure, but the invention is not limited to this, and for example, an arcuate tunnel gate may be adopted.

In this embodiment, the split mold 1 is the fixed side and the split mold 2 is the movable side. The split piece 2 provided in the tunnel gate 12 is provided with a slide piece 3 facing the tunnel gate 12, the slide piece 3 is pivotally supported by a push-up rod 31, and the push-up rod 31 is the first extruded plate 4. Through the through hole 43 provided in the second extrusion plate 5 and by pushing the knock bar 7 upward, the slide piece 3 is slid in the mold opening / closing direction so that the gate port 21 can be blocked. It is arranged.

A knockout pin 41 for a runner and a knockout pin 42 for a molded product are fixed to the upper surface of the first extruded plate 4, and a protruding pin 44 is provided to the second extruded plate 5 on the lower surface of the first extruded plate 4. It is arranged so as to come into contact with the mounting plate 6 when the mold is clamped through the through hole 51. On the upper surface of the second extruding plate 5, a stopper pin 53 protrudes through a through hole 45 provided in the first extruding plate 4, and a slide piece 3 attached to the second extruding plate 5 via a push-up rod 31 is provided. When the gate opening 21 is blocked by sliding in the mold opening / closing direction, the stopper pin 53 comes into contact with the lower surface of the split mold 2 and the slide piece 3 is restricted so that it cannot move further upward.

Further, as shown in FIGS. 2 and 4, the second extruded plate 5 has an opening for the knock rod 7 to push up the first extruded plate 4 when the molded product T and the runner R are released from each other. In order to form 53, a slide piece member 52 is arranged, and a guide guide 54 provided on the second extrusion plate 5, a convex portion 55 provided on the slide piece member 52, a rod 56 and a hydraulic cylinder (not shown) are used to form a metal. The structure is such that it can slide in the direction orthogonal to the opening and closing direction of the mold.

Next, a mode of use of the injection molding die of this embodiment will be described. First, as shown in FIG. 1, the split molds 1 and 2 are clamped, and the plasticized resin is injected into the cavity 11 through the runner R, the tunnel gate 12, and the gate port 21. At this time, the cross-sectional area of the gate opening is large because the slide piece 3 is located below.

Then, as shown in FIG. 3, before the resin is solidified and the resin is solidified, the knock rod 7 is raised to push up the second extrusion plate 5. Then, the push-up rod 31 attached to the second pushing plate 5 also rises, and the slide piece 3 attached to the push-up rod 31 also rises. However, the stopper pin 51 provided on the upper surface of the second extruding plate 5 passes through the through hole 45 provided in the first extruding plate 4 and comes into contact with the lower surface of the split mold 2 to restrict upward movement. . At this time, the slide piece 3 blocks the gate opening 21.

Next, when the solidification of the resin is completed, the knock rod 7 is moved downward, the second extruding plate 5 is lowered to the position shown in FIG. 1, and the mold is opened. Further, as shown in FIG. 2, the slide piece member 52 is composed of a guide guide 54 provided on the second pushing plate 5, a convex portion 55 provided on the slide piece member 52, a rod 56 and a hydraulic cylinder (not shown). The opening 53 is formed in the second extrusion plate 5 by sliding in a direction orthogonal to the opening / closing direction of the mold.

Thereafter, as shown in FIG. 4, the knock bar 7 is pushed through the opening 53 provided in the second extruding plate 5 and the first extruding plate 4 is pushed up. Then, the knockout pin 41 for the runner and the knockout pin 42 for the molded product, which are provided on the upper surface of the first extruded plate 4, push up the runner R and the molded product T to release them from each other. The effect similar to that described in the section of the action and effect of the invention of the description is achieved, such as the finishing process of the gate mark can be eliminated.

In this embodiment, since the opening 53 is formed in the second extruding plate 5, the slide piece member 52 is provided, and the guide guide 54 and the sliding piece member provided on the second extruding plate 5 are provided. The convex portion 55 and the rod 56 provided on 52 and a hydraulic cylinder (not shown) are configured to be slidable in a direction orthogonal to the opening / closing direction of the mold, but the present invention is not limited to this, and as shown in FIG. The slide plate 8 similarly having the opening 81 is arranged below the second extrusion plate 61 having the opening 60 previously formed therein. When the molded product T and the runner R are released from each other, only the slide plate 8 is slid in a direction orthogonal to the opening / closing direction of the mold by a hydraulic cylinder (not shown) so that the opening 60 and the opening 81 are communicated with each other, and the knocking is performed. The rod 7 may push up the first pushing plate 9.

[Brief description of drawings]

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

FIG. 2 is a partially enlarged perspective view taken along the line AA of FIG. 1 showing a slide piece member used in the embodiment.

FIG. 3 is a cross-sectional view showing a state in which the gate port of the embodiment is blocked.

FIG. 4 is a cross-sectional view showing a mold release state of a molded product and a runner of the same embodiment.

FIG. 5 is a sectional view showing an injection molding die according to another embodiment of the present invention.

[Explanation of symbols]

1, 2: Split mold 3: Slide piece 4: First
Extruded plate 5: Second extruded plate 6: Mounting plate 7: Knock rod 52: Slide piece member

Claims (1)

[Scope of utility model registration request] 1. An injection molding mold comprising a split mold which is divided into two parts, wherein one of the split molds is provided with a tunnel gate communicating with a cavity, wherein the tunnel gate is provided. The mold for injection molding is characterized in that the split mold is provided with a slidable slide piece facing the tunnel gate in order to block a gate port communicating with the tunnel gate of the cavity.