JPH08142135A - Injection mold - Google Patents

Abstract

PURPOSE: To effectively reset an ejector plate by a simple structure without using a return pin by providing a magnet for attracting the plate at the end of an ejector rod. CONSTITUTION: Resin is filled in a mold 10 in the state that the mold 10 is closed, cooled and solidified. The movable side part of the mold is moved leftward to open the mold. Then, when a hydraulic cylinder 29 is operated to extend an ejector rod 29a, ejector plates 27a, 27b are pressed to a magnet 30 according to the rod 29a, and guided by an ejector guide pin 28 to move rightward. The pin 26 fixed to the plates 27a, 27b is also moved rightward, and a molded form S is ejected by the end of the pin 26.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for injection molding. More specifically, the present invention relates to an injection molding die configured to eject and take out a product formed by injection molding with an ejector pin.

[0002]

2. Description of the Related Art Conventionally, an injection molding die provided in an injection molding machine is generally composed of a fixed side portion and a movable side portion. When manufacturing a molded product using an injection molding mold, first fill the mold with resin, solidify it by cooling, and then retract the movable side part to open the mold, which results in a solidified product. Taken out. In this case, when the movable side part is retracted and the mold is opened, the molded product is left in the movable side part, and it becomes necessary to remove the molded product from the movable side part. In order to remove the molded product from the movable side part, the injection molding die is provided with an ejector pin, and by ejecting the ejector pin in a state where the mold is opened, the molded product is removed from the movable side part. In the injection-molding die thus configured, it is necessary to return the ejected ejector pin to the original position, and for that reason, the return pin is normally provided. That is, as shown in FIG. 3, the ejector plate 27
The return pin 31 is attached to a and 27b, and the return pin 31 is provided with the compression spring 32 between the ejector plate 27a and the receiving plate 22, so that the ejector rod 29a is extended by the hydraulic cylinder 29. When the molded article S is ejected from the mold and removed from the mold, the ejector plates 27a and 27b are returned by the restoring force stored in the compression spring 32. Therefore, the ejector rod 26 is returned to the original position.

However, in such a structure of the conventional injection molding die, since the return pin is required, the number of parts is increased, the assembling work is complicated and the cost is increased, and at the same time, the space where the originally molded product is to be manufactured is required. However, there was an adverse effect that it was limited by the presence of the return pin. Further, since the ejecting operation is frequently performed, the compression spring is deteriorated, which causes a defective return of the ejector plate.

[0004]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an injection molding die which can surely perform a returning operation of an ejector plate with a simple structure without using a return pin. That is.

[0005]

In order to solve the above problems, according to the present invention, there is provided an injection molding die having a fixed side portion and a movable side portion, wherein the movable side portion has an ejector plate. Fixed to the ejector pin for ejecting a cooled and solidified molded product and an ejector rod for ejecting the ejector plate, the ejector plate is attracted to the tip of the ejector rod. Provided is a mold for injection molding, which is provided with a magnet for In a preferred aspect of the present invention, the magnet is fixed to the tip of the ejector rod with a screw.

[0006]

By providing the magnet for attracting the ejector plate at the tip of the ejector rod, when the ejector rod is contracted, the ejector rod is attracted to the ejector plate by the magnetic force of the magnet. The pin is returned to its original position.

[0007]

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. As shown in FIG.
The injection mold according to the embodiment of the present invention indicated by reference numeral 10 as a whole is divided into a fixed side portion and a movable side portion with a dividing surface (parting line) as a boundary. The fixed side portion is fixed to a fixed side die plate (not shown) of the injection molding machine, and the movable side portion is attached to the movable side die plate (not shown). The fixed side portion and the movable side portion are usually positioned and connected by four guide pins (not shown). The fixed side portion is a fixed side mold plate 11 which is a main body of a mold attached to the fixed side die plate of the molding machine, and a fixed side mounting plate 12 for fixing the fixed side mold plate 11 to the fixed side die plate. Fixed side template 11
And a sprue bush 13 incorporated in the. A locating ring 14 for centering the nozzle (not shown) of the injection molding machine and the sprue bush 13 is attached to the center of the fixed side mounting plate 12. The movable side portion is a movable side mold plate 21 which is a main body of a mold attached to the movable side die plate of the molding machine, a receiving plate 22 attached to the movable side mold plate 21 to reinforce the movable side mold plate 21, and a movable side. Movable side attachment plate 23 for attaching the entire part to the movable side die plate
In order to secure the protrusion stroke of the molded product,
And a spacer block 24 for mounting the movable-side mold plate 23 at a predetermined interval and mounting it on the movable-side mounting plate 23.

The stationary mold plate 11 is provided with a core 15 which constitutes a mold engraving portion on the surface of the molded product, and the movable mold plate 21.
Is provided with a cavity 25 forming a die-engraved portion on the back surface of the molded product. Further, an ejector pin 26 for ejecting the cooled and solidified product S is provided at a position corresponding to the cavity 25 on the movable side portion. A flange 26a is attached to the end of the ejector pin 26 on the side opposite to the cavity 25, and the flange 26a is fixed by being sandwiched between two ejector plates 27a and 27b. The ejector plates 27a and 27b are ejector guide pins 28 (only one is shown for simplicity).
Is guided by sliding in the horizontal direction in the drawing. On the other hand, a hydraulic cylinder 29 is installed adjacent to the movable side portion of the injection molding die 10, and an ejector rod 29a extending from the hydraulic cylinder has an opening 23a provided at the center of the movable side mounting plate 23. It is located inside. A female screw is provided at the tip of the ejector rod 29a, and a magnet 30 provided with a male screw is screwed into the tip of the ejector rod 29a. Magnet 30
Is preferably positioned so that the surface of the magnet 30 contacts the surface of the ejector plate 29b in a state where the ejector rod 29a is not extended.

Next, the operation of the injection molding die 10 configured as described above will be described. First, as shown in FIG. 1, a mold is filled with resin in a state where the mold is closed, and then the resin is cooled and solidified. Thereafter, as shown in FIG. 2, the movable side portion of the mold is moved leftward in FIG. 2 to open the mold. Next, when the hydraulic cylinder 29 is operated to extend the ejector rod 29a, the ejector plates 27a and 27b are pushed by the ejector rod 29a and hence the magnet 30, and guided by the ejector guide pin 28 to move rightward in FIG. . Then, the ejector pin 26 fixed to the ejector plates 27a and 27b also moves to the right, and the molded product S is projected by the tip of the ejector pin 26. After that, when the hydraulic cylinder 29 is operated to contract the ejector rod 29a, the ejector rod 29a is moved by the magnetic force of the magnet 30 so that the ejector plate 27a,
Since it is adsorbed by 27b, the ejector plate 27
Therefore, the ejector pin 26 also returns to its original position. The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the invention described in the claims, and those modifications are also included in the scope of the present invention. Needless to say.

For example, in the above embodiment, the magnet 3
0 is attached to the tip of the ejector rod 29a by a screw, but other attaching means such as adhesion may be used, or an iron piece may be fixed to the tip of the ejector rod 29a and a magnet may be attached via this iron piece. It can also be installed.

[0011]

According to the present invention, a return pin is not provided, and the magnet provided at the tip of the ejector rod causes the ejector pin to return to the original position. It can be used for manufacturing, and it is possible to reduce the number of parts, simplify the assembly work, and reduce the cost.
Further, the defective return of the ejector plate due to the deterioration of the compression spring has been eliminated.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a state in which a mold is closed in an injection molding mold of the present invention.

FIG. 2 is a cross-sectional view showing a state in which the mold is opened in the injection molding mold of FIG.

FIG. 3 is a cross-sectional view showing a conventional injection molding die.

[Explanation of symbols]

 10 Mold for Injection Molding 11 Fixed-side Mold Plate 15 Core 21 Movable-side Mold Plate 25 Cavity 26 Ejector Pins 27a, 27b Ejector Plate 30 Magnet S Molded Product

Claims (2)

[Claims] 1. An injection molding die having a fixed side portion and a movable side portion, wherein the movable side portion is an ejector pin fixed to an ejector plate for ejecting a cooled and solidified molded article. An injection molding die provided with an ejector rod for ejecting an ejector plate, wherein a magnet for adsorbing the ejector plate is provided at a tip of the ejector rod. Mold. 2. A mold for injection molding according to claim 1, wherein the magnet is fixed to the tip of the ejector rod by a screw.