JPH0890614A - Injection molding die - Google Patents

Abstract

PURPOSE: To prevent a projected bulge from occurring in a rib part by a simple mechanism by a method wherein out of a plurality of ejector pins, an ejector pin with a rib formed at the top end thereof is provided with a fixing seat at the bottom end thereof and loosely fitted in a first ejector plate from the rear side of the first ejector plate, and a stopper for preventing the retraction of the ejector pin is provided. CONSTITUTION: In the molding of a molded article having a rib 3a, fixing seats 4a, 5a are respectively provided at the bottom ends of an ejector pin 4 for a molded article body and an ejector pin 5 for a rib 3a. In a second ejector plate 7 disposed under a first ejector plate 6, a stopper 8 is provided just under the fixing seat 5a so as to form a gap C. At the time of a mold opening, the first and second ejector plates 6, 7 are pushed by an ejector rod 10, whereby the ejector pin 4 firstly starts to push a molded article 3. At this time, the gap C shifts to above the fixing seat 5a to prevent the rib 3a from being pressed. In this state, the ejector pin 5 ejects the molded article while being prevented from further moving backward by the stopper 8.

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, and more particularly to an injection molding die having a rib extruding pin.

[0002]

2. Description of the Related Art Conventionally, all extrusion pins of a molded product provided in an injection molding die are operated at the same timing to project the molded product forward and release the molded product. Notch the tip to form a cavity that will become a rib between the notch and the movable die.
In the case of an injection mold having a height filled with a molten resin, that is, a deep rib is molded, first, another extruding pin for extruding a molded product is operated, and at the tip of this extruding pin. At the same time, the molded product is not pushed out and is operated with a delay (see Japanese Utility Model Laid-Open No. 4-7121). The purpose of this is to prevent a convex bulge from being generated on the back surface (design surface of the product) of the molded product body provided with the rib when the rib is pushed up by the extrusion pin. is there.

[0003]

However, in the mechanism for providing the deep rib as described in the above-mentioned Japanese Utility Model Laid-Open No. 4-7121, even if the extrusion of the rib root is delayed, the rib root When the thick portion is insufficiently cooled, a convex bulge is generated on the back surface of the ribbed molded article body, and the tip end of this push pin operates simultaneously with other push pins, If the rib is extruded while only the tip portion is insufficiently cooled, there is a problem that the tip of the rib is crushed and the height of the rib changes.

The present invention has been made in view of the above problems, and an object of the present invention is to solve these problems and to provide a simple rib extruding mechanism to facilitate processing and assembling. (EN) Provided is an injection molding die that is easy and does not cause a whitening phenomenon or a convex bulge on the surface of a molded product body or a molded product body in a ribbed portion.

[0005]

In the injection molding die of the present invention, a movable die mounting plate and a movable die plate of an injection molding die having a fixed side die plate and a movable side die plate are provided. In between, a first ejector plate and a second ejector plate are provided in contact with each other, a plurality of push-out pins are provided in this first ejector plate by fitting a fixed seat at the lower end of the push-out pin, An extrusion pin that forms a rib of a molded product at the tip is loosely fitted in the fixing seat at the lower end of the extrusion pin from the back side of the first ejector plate in the axial direction of the extrusion pin, and further prevents the extrusion pin from retracting. A stopper is provided so as to abut the fixed seat, penetrate the second ejector plate, and be provided between the stopper and the movable die mounting plate.

[0006]

In the injection molding die of the present invention, among the push-out pins fitted to the first ejector plate, the fixed seat of the push-out pin forming the rib of the molded product at the tip is the first ejector plate. Since there is play in the axial direction of the extrusion pin from the back side of the product and it is fitted to the first ejector plate, it operates later than the extrusion pin of other products by the amount of play when the mold is opened, and this extrusion pin against the rib Since there is no pushing-up action due to, the occurrence of convex bulges on the back surface of the molded product body and the phenomenon of whitening are prevented, and the ribs can be molded normally without deformation of the rib tips.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing an example of the injection mold of the present invention, showing a mold closed state. In FIG. 1, the molded product body 3 is molded in a cavity formed between the fixed mold plate 1 and the movable mold plate 2, and the molded product body 3 is relatively higher than the back side of the molded product body 3. The so-called deep rib 3a is provided on the movable side mold plate 2.

Reference numeral 4 denotes an extruding pin for penetrating the body of the molded article, which is provided penetrating the movable side mold plate 3, and 5 also has a rib 3a for extruding the root 3b and the tip 3c of the rib 3a. It is an extrusion pin 3a.

Fixing seats 4a and 5a, which are fitted to the first ejector plate 6, are provided at the lower ends of the push-out pins 4 and 5, respectively. Above, molded article body 3
The push-out pin 4 that abuts on the
It is fitted and fixed in a fitting hole 6a provided in the first ejector plate 6. The push-out pin 5 that pushes out the rib 3a is loosely fitted in a fitting hole 6b in which the fixed seat 5a at the lower end is provided in the first ejector plate 6 with a gap C provided in the axial direction of the push-out pin 5.

A second ejector plate 7 is provided below the first ejector plate 6, a pin-shaped stopper 8 is provided immediately below the fixed seat 5a of the push-out pin 5 of the second ejector plate 7, and a fixed seat is provided at the upper end. 5a is provided in contact with the back surface and the lower end is provided in contact with the mold mounting plate 9 so as to secure a gap C between the second ejector plate 7 of the fixed seat 5a loosely fitted in the mold closed state. Has been done.

[Operation of the Embodiment] The operation of the embodiment will be described below. FIG. 2 is a cross-sectional view showing a mode of operation of the injection molding die shown in FIG. 1, showing a state immediately after entering the mold opening. In FIG. 2, when the molding of the molded product 3 is completed and the mold opening is started, the first ejector plate 6 and the second ejector plate 7, which are in contact with each other due to the operation of the pushing rod 10, are simultaneously moved toward the fixed-side mold plate 1. When pushed, the push pin 4 previously fixed to the first ejector plate 6 begins to push the molded product 3 forward, and the tip of this push pin 4 projects from the movable side mold plate 2 and the fixed side of the molded product 3. The mold release from the template 2 is started.

At this time, since the push-out pin 5 does not move forward but stays as it is, the push-out pin 5 is relatively retracted, and the gap C under the fixed seat 5a is shown in the figure. As described above, the root 3b and the tip 3c of the rib 3a, which has been moved to the upper side of the fixed seat 5a, is not pressed by the push-out pin 5, and a gap corresponding to the gap C is formed at the tip.

With the gap C formed, the second ejector plate 7 penetrates under the solid seat 8 and the stopper 8 abutting the movable die mounting plate 9 causes the push-out pin 5 to further retract. However, when the mold opening further progresses, the extrusion pin 5 and the extrusion pin 5 also advance, and the extrusion of the molded product and the mold opening are completed. Therefore, the extrusion pin 5 does not press the rib 3a, and even if there is insufficient cooling at the tip or the base of the rib 3a, no convex bulge or whitening occurs on the design surface on the front side of the molded product body. Also, the deformation of the tip is prevented.

The number and arrangement of the extruding pins for forming the ribs provided in the injection mold of the present invention and the extruding pins for extruding the molded product are not limited to the examples, and the molded product is not limited. According to the shape, size, etc., a plurality of materials are appropriately provided, and the molding of ribs of the molded product and the extrusion of the molded product are supported.

[0015]

According to the injection molding die of the present invention, among the extrusion pins fitted to the first ejector plate, the extrusion pin fixing seat for forming the rib of the molded product at the tip is the first. Since there is play in the axial direction of the push-out pin from the back side of the ejector plate and it is fitted to the first ejector plate, it operates later than the push-out pin of other products by the amount of play when the mold is opened, Since there is no pushing up action by the extrusion pin, the occurrence of convex bulges on the back surface of the molded product body and the whitening phenomenon are prevented, and the rib tip is not deformed and the rib can be molded normally. . Therefore, it is preferably used as an injection mold for an injection molded product having a rib.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of an injection molding die of the present invention.

FIG. 2 is a cross-sectional view showing a mode of operation of the injection molding die shown in FIG.

[Explanation of symbols]

 1 Fixed Side Mold Plate 2 Movable Side Mold Plate 3 Molded Product Main Body 3a Rib 3b Root 3c Tip Part 4, 5 Extrusion Pin 4a, 5a Fixed Seat 6 First Ejector Plate 6a, 6b Fitting Hole 7 Second Ejector Plate 8 Stopper 9 Movable type mounting plate 10 Extrusion rod C Gap

Claims (1)

[Claims] 1. A first ejector plate and a second ejector plate contact between a movable mold mounting plate and a movable mold plate of an injection mold provided with a fixed mold plate and a movable mold plate. Provided in contact with each other, a plurality of push-out pins are provided on the first ejector plate by fitting a fixed seat at the lower end of the push-out pin, and among the push-out pins, a push-out pin that forms a rib of a molded product at the tip, A fixed seat at the lower end of the push-out pin is loosely fitted from the back side of the first ejector plate in the axial direction of the push-out pin, and a stopper that prevents the push-out pin from retracting abuts against the fixed seat and the second ejector plate is An injection mold which is provided between the movable die mounting plate and the movable die mounting plate.