JPH07156219A - Resin forming mold - Google Patents

Abstract

PURPOSE:To obtain a resin forming mold for molding a resin molded piece wherein a part of a product having a rib is forming an undercut. CONSTITUTION:In order to mold a molded piece W in which a base of a rib molding part 5a of a cavity 5 forms an undercut Ur, a slant push-up core 4 which moves to a slant front part with respect to a movable mold 2 by interlocking the front protrusion of the molded piece W is provided for heightening degassing effect at the rib molding section 5a, and treating the undercut when the molded piece is to be pushed out. In the slant push-up core 4, a slide pin 15 to be energized by a spring is provided. The tip of it appears and disappears in accordance with the back-and-forth movement of the slant push-up core 4 so as to treat other undercut Uo of the molded piece.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin molding die for molding a resin molded product in which a part of a product having ribs serves as an undercut portion.

[0002]

2. Description of the Related Art Conventionally, a slide core mechanism using an angular pin is known as a mechanism for processing an undercut portion in a resin molding die. This mechanism is a mechanism in which the split mold is automatically moved by using an inclined pin provided in the mold, and the molded product is projected while avoiding the undercut portion. Further, when molding a molded product having deep ribs, in order to avoid a molding defect due to insufficient gas venting of the ribs, a degassing insert piece is provided inside the mold, and a joining portion between the insert piece and the die is formed. A method of exposing the rib is known. Further, it is known that when forming a deep rib, sink marks are likely to occur at the root of the rib, and as a countermeasure against this sink mark, it is also known to form a groove-shaped recess called a so-called meat flesh at the root of the rib. Has been.

[0003]

However, in the case of a slide core mechanism using an angular pin, there are problems that the number of parts is large, the number of finishing steps is increased, and the cost is increased. Also, for example, when the slime for sinking at the root of the deep rib is an undercut part, an oblique pushing core is used, but if the angular pin mechanism and the diagonal pushing core are configured separately, There is a problem that the structure becomes more complicated and the cost becomes higher.

[0004]

In order to solve the above problems, the present invention provides a resin molding die for molding a molded product in which a part of a product having ribs serves as an undercut part. The diagonal push-up core that moves diagonally forward in conjunction with the forward projection of the molded product is provided to degas the ribs generated during molding by this diagonal push-up core and undercut the molded product when it is projected. To do. A slidable slide pin is provided inside the diagonal push-up core, and the slide pin is used to process other undercut portions of the molded product.

[0005]

[Operation] Degassing from the ribs at the time of molding by the diagonal push-up core and avoiding the undercut portion by the diagonal push-up core when the molded product is projected,
The number of parts is reduced and simplification is possible. Furthermore, if a slidable push-up pin is provided inside the diagonal push-up core and another undercut portion can be processed by this slid-up core, even a molded product having a complicated shape can be molded with a simple mold.

[0006]

Embodiments of the resin molding die of the present invention will be described with reference to the accompanying drawings. 1 is a partial vertical cross-sectional view of the present resin molding die, FIG. 2 is an enlarged view of a main part, and FIG. 3 is an enlarged view of ribs.

As shown in FIG. 1, the resin molding die of the present invention is provided with a movable mold 2 which is movable up and down in the figure with respect to a fixed mold 1 to clamp the mold to open the mold. Cavity 5
Is provided with a diagonal push-up core 4.

A first projecting plate 6 and a second projecting plate 7 are provided below the movable mold 2. A vertically movable projecting rod 8 is in contact with the lower surface of the second projecting plate 7, and A base end portion of a protruding pin 10 is connected to the protruding plate 6, and the protruding pin 10 slidably penetrates the movable die 2 so that its distal end faces the surface of the cavity 5.

A base end portion of an inclined rod 12 is connected to the second pushing plate 7 via a slide core guide unit 11, and the inclined rod 12 is slidable on a guide bush 13 of the movable die 2. The tip end portion is penetrated and connected to the obliquely pushing up core 4.

By the way, the cavity 5 is provided with a rib forming portion 5a for forming a deep rib on a molded product,
The diagonal push-up core 4 is provided for discharging the gas of the rib molding portion 5a during molding and for treating the undercut portion Ur formed in the rib molding portion 5a during mold release. The details will be described.

Usually, when forming a deep rib on a molded product,
The thickness of the root of the rib is set to 50 to 80% of the base wall thickness, but in the case of a deep rib, this value is exceeded to secure the thickness of the rib tip, and as shown in FIG. A sink d called a hot spot is likely to occur on the back surface side of the rib R, and insufficient filling is likely to occur at the rib tip.

Therefore, in the prior art, this rib molding portion is provided with the structure shown in FIG.
The degassing insert 51 as shown in FIG.

Therefore, in the present invention, in order to further prevent sink marks, as shown in FIG. 3, a protrusion 4a at the upper end of the oblique pushing-up core 4 is used to form a groove-shaped recess called a meat thin portion at the root of the rib-shaped portion 5a. The diagonal push-up core 4 is moved diagonally forward in the opposite direction to the side on which the projection 4a is formed for the treatment of the undercut portion Ur of the rib formed by the projection 4a.

Moreover, the end face of the obliquely pushing up core 4 is made to face the rib forming portion 5a to substitute for the conventional degassing insert piece 51 (FIG. 4).

By the way, as shown in FIG.
The slide pin 15 as shown in FIG.

The slide pin 15 is housed in the housing hole 4b of the diagonal push-up core 4 and is biased rearward by the spring 16.

The movable die 2 is provided with a regulation inclined surface 2a which comes into contact with the rear surface of the slide pin 15 and adjusts the protruding / retracting amount of the slide pin 15, and the inclination direction and inclination angle of the regulation inclined surface 2a are as described above. It is inclined at the same angle as the inclination direction of the inclination rod 12 and at a deeper angle than that.

The tip portion 15a of the slide pin 15
Is configured to project into the cavity 5 toward the outside of the storage hole 4b in the mold clamped state. Therefore, the tip portion 15a protruding into the cavity 5 is configured as another undercut portion Uo.

Further, when the diagonal push-up core 4 is advanced diagonally forward with respect to the movable die 2, as shown in FIG. 5, since the inclination angle of the regulation inclined surface 2a is large, the slide pin 15 is gradually retracted, Finally, the tip portion 15a is designed to be retracted into the storage hole 4b.

Then, in order to finally regulate the retracted position of the slide pin 15 which is separated from the regulation inclined surface 2a, a stopper 17 as shown in FIG. 6 is provided.

In the resin molding die configured as described above, the molten resin is filled in the cavity 5 in the mold clamping state as shown in FIG.

Then, the gas generated in the rib forming portion 5a is
The ribs are discharged from the joint between the diagonal push-up core 4 and the movable die 2, and the rib root portion has a protrusion 4a of the diagonal push-up core 4, so that the ribs have sink marks or the like on the back surface side. No defective molding occurs. Also slide pin 15
A hole is formed in the molded product W by the tip portion 15a of the.

When the molding is completed and the mold is opened, the first and second projecting plates 6 and 7 are moved forward by the projecting rod 8.

For this reason, the projecting pin 10 advances straight forward, and along with this, the obliquely pushing up core 4 advances obliquely forward along the inclination direction of the inclined rod 12. Therefore,
As shown in FIG. 5, the protrusion 4 a forming the undercut portion Ur of the rib is smoothly separated from the molded product W.

At the same time, the tip end portion 15a of the slide pin 15 also immerses in the obliquely pushing up core 4, and the other undercut portions Uo formed so far do not interfere with the protrusion.

That is, the molded product W is smoothly separated from the movable mold 2 by such a mold structure.

[0027]

As described above, the resin molding die of the present invention is
In the past, separate parts were used for the degassing inserts for degassing the ribs, measures for sinking the surface of the molded product, and the angala pin mechanism for treating the undercut parts. Since all of them are processed by one diagonal push-up core, it is possible to save the work such as mold matching work for the fixed mold and the movable mold, which is required when assembling slide pins as in the past. , Only the adjustment for the movable type is required. Moreover, the structure is simple and inexpensive.

[Brief description of drawings]

FIG. 1 is a partial vertical sectional view of the present resin molding die.

[Fig. 2] Enlarged view of the main part

FIG. 3 is an enlarged view of the rib.

FIG. 4 Conventional view of rib forming

FIG. 5: Action diagram

6 is a sectional view taken along line AA of FIG.

[Explanation of symbols]

 1 Fixed type 2 Movable type 4 Oblique push-up core 15 Slide pin Ur Undercut part of rib Uo Other undercut part W Molded product

Claims (2)

[Claims] 1. A resin molding die for molding a molded product in which a part of a product having ribs serves as an undercut part, the diagonally front facing the undercut part of the product and interlocking with the forward protrusion of the molded product. An oblique push-up core that moves to
A resin molding die, characterized in that the oblique push-up core is used to degas the ribs generated during molding and to perform an undercut process when a molded product is projected. 2. The slidable push-up core is provided with a slide pin that can be retracted and retracted, and the slide pin is used to process another undercut portion of the molded product. 1. The resin molding die according to 1.