JPH0716980B2 - Injection mold - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding die having a slide die on the side of a core die of a movable die.

[0002]

2. Description of the Related Art A mold in which a through-hole, a window hole or the like can be formed in a molded product injection-molded around a core mold has a slide mold having a pin or a core for punching on the side of the core mold. .

Various attempts have been made so far with respect to this slide type moving means, but in the case of a die which slides the slide type in synchronization with the opening and closing of the die by an angular pin provided on the fixed die side. It is designed so that the tip end surface of the slide type pin or the core for perforation is brought into close contact with the side surface of the core die when the die closing is completed.

[0004]

For this reason, in a die having a slide die, a portion where the slide die of the slide die and the fixed die fits is required to have a particularly high processing precision and assembling precision. It is more costly than the mold.

Further, since the contact of the tip end surface such as the pin with the side surface of the core die is merely a contact, the contact is likely to be impaired due to the fit of the slide die, the abrasion due to the repeated use of the die, etc. However, there is a problem that burrs are easily generated in the hole or window of the molded product.

The present invention was conceived in order to solve the problems of the injection molding die having the above slide die, and its purpose is to utilize the elastic deformation recovery force of the shape memory alloy, adhesion such as a pin to the core mold side, to provide a new injection mold that can be performed under a sufficient pressure.

[0007]

One of the features of the present invention according to the above-mentioned object is for injection molding having a slide mold in which a pin facing a side surface of the core mold is embedded in a side part of the core mold of a movable mold. In the die, a pressing member made of a shape memory alloy is provided at the rear of the pin.

Another feature of the present invention is an injection molding mold having a slide mold in which a core for perforation facing the side surface of the core mold is provided on the side of the core mold of the movable mold.
The slide type pressure receiving portion is provided with a pressing member made of a shape memory alloy.

[0009]

In the above structure, the pin or the core for perforation abutting on the side surface of the core comes into close contact with the elastic deformation recovery force generated by the compressive deformation of the pressing member by the shape memory alloy. In addition, the close contact is maintained under a pressing force that can oppose the injection pressure, and the occurrence of burrs due to the gap is prevented.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference numeral 1 in the drawing is a fixed mold having a core mold 3 of a movable mold 2 and a single cavity 4 for closing the mold at a parting part.

On both sides of this cavity 4, a movable mold 2 is provided.
The accommodating portions of the slide dies 5 and 6 provided on both sides of the core die are recessed, and the angular pins 9 and 10 are accommodated in the accommodating portions 7 and 8 , respectively.
Are projected at the required angle.

Outer end surfaces of the main bodies of the slide molds 5 and 6 and the accommodating portions 7 and 8 are formed into tapered surfaces having the same angle as the angular pins 9 and 10, and an inner end surface is formed into the same surface as the cavity side surface. is there.

The main bodies of the slide dies 5 and 6 include a dovetail-shaped slide groove 11 provided on the parting surface of the movable die 2.
12 is fitted in, and the insertion holes for the angular pins 9 and 10 are provided inside.

In the main body of the one slide mold 5, a pin 13 facing the side surface of the core mold 3 is fitted with a pressing member 14 made of a shape memory alloy at the rear part.

On the inner end of the other slide die 6, a core 15 for perforation facing the side of the core die is attached, and the taper portion of the accommodating portion 8 in which the outer end of the slide die 6 is accommodated, A pressing member 16 made of a shape memory alloy is provided.

The shape memory alloy has a shape recovery temperature of -10 to 100 ° C., a tensile strength of 70 to 110 g / cm ² ,
A TiNi alloy manufactured by Kobe Steel, Ltd. having a material property of a density of 6.4 g / cm ³ can be adopted. This shape memory alloy has a superelastic characteristic in which a large deformation strain of several percent is restored in the shape recovery temperature range, and even if it deforms by 8 percent, it returns to its original shape upon unloading, When recovering the shape, a large recovery force of more than 30 kg / mm ² is generated.

In the above structure, the movable mold 2 approaches the fixed mold 1 to close the mold, the core mold 3 is positioned in the cavity 4, and the angular pins 9 and 10 are slid molds 5.
When the slide dies 5 and 6 are slid in the direction of the core dies 3 when they are fitted into the respective accommodating portions 7 and 8, the pin 13 and the drilling core 15 are in contact with the core side surfaces. Become.

Therefore, the protruding dimensions of the pin 13 and the drilling core 15 are made slightly longer in advance, and while the slide molds 5 and 6 are completely set in the accommodating portions 7 and 8, the pin 13 and the drilling core 1 are formed.
If the retracting force is made to act by the surplus length of 5, this retracting force acts on the pressing members 14 and 16, and compression deformation occurs there. The amount of deformation at this time depends on the applied pressure.

In the pressing members 14 and 16 that are compressed and deformed by the pin 13 or the slide die 6, elastic deformation recovery force is generated and acts as an abutting force. Therefore, the tip surfaces of the pin 13 and the core 15 for boring are: Adhere to the side of the core mold with sufficient pressing force. Since this close contact is maintained while the mold is closed, it is difficult to form a gap that causes burr.

When the mold is opened, the slide molds 5 and 6 are pushed rearward by the angular pins 9 and 10, so that the contact force is removed as the mold is opened, and the pin 13 and the drilling core 1 are removed.
5 is separated from the core mold 3 as shown in FIG.
It escapes from the room and the traces remain as through holes and windows.

[0021]

As described above, the present invention utilizes the elastic deformation recovery force of the shape memory alloy for the slide type pin or the core for punching provided on the side of the core of the movable mold,
Since the core mold is closely contacted with the side surface, the core mold side surface can be more surely contacted as compared with the case of mere contact, and it is possible to prevent the occurrence of burrs that are likely to occur until now.

Further, since it is only necessary to provide the shape memory alloy as the pressing member at the rear portion of the pin or the rear end portion of the slide type, it is not necessary to make the processing precision and the mounting precision strict as in the past, and some degree of wear is caused. Since the obstacles due to the above can be compensated, it can sufficiently withstand long-term use, and the structure does not become particularly complicated, so that the cost of this type of mold can be reduced.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a mold for injection molding according to the present invention when the mold is closed. FIG. 2 is a vertical sectional view of the same when the mold is opened.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixed mold 2 Movable mold 3 Core type 4 Cavity 5 Sliding type 6 Sliding type 7 Housing part 8 Housing part 9 Angular pin 10 Angular pin 13 Pin 14 Pressing member (shape memory alloy) 15 Perforating core 16 Pressing member (shape) Memory alloy)

Claims (2)

[Claims] 1. An injection molding die having a slide die in which a pin facing a side surface of the core die is embedded in a side portion of a core die of a movable die, and a press formed by a shape memory alloy at a rear portion of the pin. An injection-molding die characterized by comprising a member. 2. An injection molding die having a slide die in which a core for punching is provided on a side portion of a core die of a movable die so as to face a side surface of the core die, and a shape memory alloy is provided in a pressure receiving portion of the slide die. An injection-molding die, comprising a pressing member formed by.