JPH09193172A - Mold assembly - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely release a bottom from a slant core for forming a groove part in a mold assembly for molding the bottom by a method wherein an engaged state of a bottom groove part with a lid catch part is secured in an accomodating case for mini disks. SOLUTION: In a bottom groove part, a face to a lid side is made undercut shaped. Thereby, a spring effect is obtained by engagement of the groove part with a catch part. In a projected part 53 of a slant core 51 forming the groove part, a first side face 53a to a fixed tool 46 side, and a second side face 53b to the opposite side are inclined in the same direction. In order to raise releasability, a slant angle α of the first side face 53a is made larger than a slant angle β of the second side face 53b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold device used for injection molding of resin, and more particularly to a mold device provided with an inclined core for forming an undercut portion.

[0002]

2. Description of the Related Art FIG. 5 shows a mini disk (MD or M
The storage case 1 for O) is shown. This storage case 1
Is configured by connecting the bottom 2 and the lid 3. The bottom 2 includes a base surface portion 6 having a substantially rectangular flat plate shape, and the base surface portion 6.
And a side wall portion 7 that is bent substantially vertically from the edge of the. The lid 3 also has a substantially rectangular flat plate-shaped base portion 8 and the base surface portion 8
And a side wall portion 9 that is bent substantially vertically from the edge of the. In order to fix the bottom 2 and the lid 3 to each other, groove portions 11 are formed on the inner surface sides of the side wall portions 7 on both sides of the bottom 2 and on the outer surface sides of the side wall portions 9 on both sides of the lid 3. A claw portion 12 that engages with the groove portion 11 is formed to project. There is a recess 13 on the outer surface side of the side wall portion 7 of the bottom 2. In the case of the conventional mini disk, in the groove portion 11 of the bottom 2, both the first side surface 11a on the base surface portion 6 side and the second side surface 11b on the opposite side are formed parallel to the base surface portion 6.

By the way, the bottom 2 and the lid 3 are integrally molded products of resin. Considering molding the bottom 2, for example, as shown in FIG. 4, the opening / closing direction between the fixed die 16 and the movable die 17 (hereinafter referred to as the main die opening / closing direction A) is, of course, a direction orthogonal to the base surface portion 6 ( Since the groove 11 and the recess 13 are undercut, the groove 11 and the recess 13 are undercut.
Therefore, processing for this undercut is required. The recess 13 is formed in the main body 18 of the movable mold 17 in the main mold opening / closing direction A.
Slide core assembled slidably in direction B orthogonal to
It can be processed by 19. Further, the groove portion 11 can be processed by using the inclined core 20. This inclined core 20 is a main body of the movable die 17.
18 is slidably assembled in a direction C inclined toward the center of the bottom 2 toward the fixed mold 16 side with respect to the main mold opening / closing direction A. Incidentally, the pair of inclined cores 20 are symmetrically provided in correspondence with the grooves 11 on both sides of the bottom 2. The inclined core 20 has a convex portion 21 that forms the groove 11. In the conventional mold device, the fixed mold 16
Both the first side surface 21a on the side and the second side surface 21b on the opposite side are planes orthogonal to the main mold opening / closing direction.

When the mold is opened, the molded bottom 2 is
First, leave the fixed mold 16. Further, as indicated by the chain line, the slide core 19 moves and comes out of the recess 13 of the bottom 2.
Then, the inclined core 20 moves toward the fixed mold 16 with respect to the main body portion 18 of the movable mold 17, and the bottom 2 is projected and released from the movable mold 17. At this time, due to the inclination, the inclined core 20 is
The movable die 17 also moves in the direction B orthogonal to the main die opening / closing direction A with respect to the main body portion 18 of the movable die 17 and thereby comes out of the groove portion 11 of the bottom 2. In this state, the bottom 2 can be taken out without any trouble.

[0005]

However, in the above-mentioned conventional mold device, the first side surface 21a on the fixed mold 16 side and the second side surface 21b on the opposite side of the convex portion 21 of the inclined core 20 are both in the main mold opening / closing direction. Since it was a plane orthogonal to A, the inclined core
Bottom 2 is the undercut for 20 moves
Although it is not present, biting between the tilted core 20 and the bottom 2 is likely to occur, and one tilted core 20 may remain unremoved from the groove portion 11 of the one side wall portion 7 of the bottom 2.
In addition, in order to improve the releasability, the surface of the convex portion 21 is also polished to make the roughness finer. However, in that case, the man-hours for manufacturing the die are increased and the releasability is improved. Has a limit.

There is also a problem in product function. That is, it is the groove portion 11 of the bottom 3 that contributes to the fixing of the bottom 2 and the lid 3 to the second surface on the side opposite to the base surface portion 6.
Although it is the side surface 11b, since the second side surface 11b is parallel to the base surface portion 6, the engagement between the groove portion 11 and the claw portion 12 of the lid 3 is uncertain. And with this engagement alone, the bottom 2
There is a risk that rattling may occur between the lid 3 and the lid 3, or the two may be separated.

In order to enhance the certainty of engagement between the groove portion 11 and the claw portion 12, the second side surface 11b of the groove portion 11 of the bottom 3 is replaced with the base surface portion 6.
It is conceivable to incline the groove portion 11 toward the back of the groove portion 11 and away from the base surface portion 6 so that the engagement between the groove portion 11 and the claw portion 12 has a spring effect. However, in this case, when the molded bottom 3 is released from the mold, the second side surface 11b undercuts in the moving direction of the tilted core 20, so that the sticking between the tilted core 20 and the bottom 2 is further generated. The problem that becomes easy arises.

The present invention is intended to solve such problems, and it is possible to mold a product in which the engagement between the groove portion and the claw portion can be ensured, and the molded product can be reliably released from the mold. It is an object of the present invention to provide a mold device that can be used.

[0009]

In order to achieve the above object, the invention of claim 1 has a base surface portion and a side wall portion bent from an end edge of the base surface portion, and an inner surface side of the side wall portion. In a mold device for molding a product having a groove portion with which a claw portion of another product is engaged, a first mold body forming an outer surface side of the product, and the base surface portion for the first mold body. A second mold body that opens and closes in a direction orthogonal to and forms the inner surface side of the product, and a tilt core slidably incorporated in the second mold body, and the sliding direction of the tilt core is The inclined core is a direction that is inclined toward the first mold body side toward the center of the product with respect to the opening / closing direction of the first mold body and the second mold body, and the inclined core is a convex portion that forms the groove portion. And the first side surface on the side of the first mold body and the second side surface on the opposite side of the convex portion are both forward. The angle formed by the first side surface and the plane orthogonal to the opening / closing direction is inclined with respect to the plane orthogonal to the opening / closing direction toward the tip of the convex portion and away from the first mold body. It is larger than the angle formed by the second side surface and the plane orthogonal to the opening / closing direction.

When the mold is opened, the molded product separates from the first mold as the first mold and the second mold are opened. Then, in the second mold body, the inclined core moves toward the first mold body, and the product is ejected and released from the second mold body. The inclined core slides in a direction inclined toward the first mold body side toward the center of the product with respect to the opening / closing direction of the first mold body and the second mold body, so that the second mold body and It also moves in a direction orthogonal to the opening / closing direction with respect to the product, and comes out of the groove of this product. At this time, the surface of the groove portion formed by the convex portion of the inclined core on the side opposite to the first mold body is undercut, and forced removal is performed. However, the angle formed by the first side surface of the convex portion with respect to the plane orthogonal to the opening / closing direction is the second side of the opposite side.
Since the angle is larger than the angle formed between the side surface and the plane orthogonal to the opening / closing direction, the mold release resistance of the entire convex portion is small, and the convex portion of the inclined core is surely removed from the groove portion of the product. On the other hand, in terms of product function, the fact that the surface of the groove opposite to the base surface is inclined toward the back of the groove away from the base is
The engagement state when the claw portion of another product is engaged with the groove portion is ensured.

According to a second aspect of the present invention, in the mold apparatus according to the first aspect of the present invention, an angle formed by the second side surface and a plane orthogonal to the opening / closing direction is relative to the opening / closing direction and the second mold body. The angle is less than or equal to the angle formed by the moving direction of the inclined core.

As described above, since the surface of the groove portion on the side opposite to the first mold body is undercut during mold release,
For smooth mold release, it is better that the angle formed between the corresponding first side surface of the convex portion and the plane orthogonal to the opening / closing direction is smaller, and at the maximum, the opening / closing direction and the second mold body are different from each other. It should be up to the angle formed by the moving direction of the inclined core.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a mold apparatus of the present invention will be described below with reference to FIGS. The product molded by the mold apparatus of this embodiment is a resin bottom 32 of a storage case 31 for a mini disk as shown in FIG.
It is. The bottom 32 is combined with a resin lid 33, which is another product, to form the storage case 31.
The bottom 32 includes a base surface portion 36 having a substantially rectangular flat plate shape and the base surface portion 36.
36 has a side wall portion 37 that is bent substantially vertically from the edge.
The lid 33 also has a substantially rectangular flat plate-like base surface portion 38 and this base surface portion.
38 has a side wall portion 39 that is bent almost vertically from the edge.
Further, in order to fix the bottom 32 and the lid 33 to each other, groove portions 41 are formed on the inner surface sides of the side wall portions 37 on both sides of the bottom 32, and on the outer surface sides of the side wall portions 39 on both sides of the lid 33. A claw portion 42 that engages with the groove portion 41 is formed to project. There is a recess 43 on the outer surface side of the side wall portion 37 of the bottom 32. Then, in the groove portion 41 of the bottom 32, the first side surface 41a on the base surface portion 36 side and the second side surface 41b on the opposite side are both from the base surface portion 36 toward the back of the groove portion 41 with respect to a plane parallel to the base surface portion 6. Inclined away. The angle α formed by the first side surface 41a and the plane parallel to the base surface portion 6 is equal to the second side surface 41b.
Is larger than an angle β formed by a plane parallel to the base surface portion 6 (see FIG. 1).

Next, the structure of the mold device for molding the bottom 32 will be described with reference to FIGS. 1 and 2. 46 is the first
The fixed type which is the mold of No. 47, the movable type which is the second mold, 47,
The fixed mold 46 and the movable mold 47 move in the vertical direction in the figure (hereinafter referred to as the main mold opening / closing direction A) to open and close, and form a cavity 48 in the shape of the bottom 32 between the molds when the mold is closed. is there. The main mold opening / closing direction A is the bottom
It is set in a direction orthogonal to the base surface portion 36 of 32, and
The fixed die 46 forms the outer surface side of the bottom 32, and the movable die 47 forms the inner surface side of the bottom 32.

The groove 41 and the recess 43 of the bottom 32 are undercut in the main mold opening / closing direction A. Therefore, the slide core 50 and the inclined core 51 are slidably incorporated in the main body 49 of the movable die 47. Slide core 50
Has a convex portion 52 that forms the concave portion 43, and the main body portion of the movable die 47.
With respect to 49, it slides in a direction substantially orthogonal to the side wall portion 37 of the bottom 32 (hereinafter, referred to as lateral direction B). The lateral direction B is orthogonal to the main mold opening / closing direction A. Further, the inclined core 51 has the convex portion 53 that forms the groove portion 41,
The inner surface of the side wall portion 37 including the groove portion 41 and a part of the inner surface of the base surface portion 36 adjacent to the side wall portion 37 are formed. The inclined core 51 penetrates the inclined hole 54 formed in the main body 49 of the movable die 47, and the bottom 32 is directed toward the fixed die 46 side with respect to the main die opening / closing direction A with respect to the main body 49. Slide in the direction C inclined toward the center of the. This direction C is located on a plane orthogonal to the side wall portion 37 of the bottom 32. Further, the movable die 47 has a protruding plate 55 that moves in the main die opening / closing direction A with respect to the main body 49 thereof. The base of the inclined core 51 is slidably connected to the protruding plate 55 in the lateral direction B. Although not shown, the groove 41
Corresponding to the bottoms 32 on both sides of the bottom 32, the inclined cores 51 are also symmetrically paired.

In the convex portion 53 of the inclined core 51, the first side surface 53a on the fixed mold 46 side and the second side surface on the opposite side.
53b is inclined toward the tip of the convex portion 53 and away from the fixed mold 46 with respect to the plane orthogonal to the main mold opening / closing direction A. The angle α formed by the first side surface 53a and the plane orthogonal to the main mold opening / closing direction A is equal to the second side surface 53b and the main mold opening / closing direction A.
Is larger than the angle β formed by the plane orthogonal to. This angle β is determined by the main mold opening / closing direction A and the inclined core 51.
Is less than or equal to the angle γ formed by the moving direction C of.

Next, the operation of the above configuration will be described. At the time of molding, as shown in FIG. 1, in a state where the fixed mold 46 and the movable mold 47 are closed, the cavity 48 is filled with a molten resin as a molding material. Then, after the resin filled in the cavity 48, that is, the bottom 32 is cooled and solidified, the mold is opened as shown in FIG. As the fixed mold 46 and the movable mold 47 open, the molded bottom 32 first separates from the fixed mold 46. Further, the slide core 50 moves in the lateral direction B in the direction away from the bottom 32 with respect to the main body 49 of the movable die 47, and the convex portion 52 of the slide core 50 becomes the concave portion of the bottom 32.
Get out of 43. Then, the ejection plate 55 moves toward the fixed mold 46 with respect to the main body 49 of the movable mold 47. Along with this, the inclined core 51 also moves toward the fixed mold 46 together with the ejection plate 55. As a result, the inclined core 51 projects the bottom 32 and separates it from the main body 49 of the movable mold 47.

At this time, the inclined core 51 is constrained so that the moving direction of the movable die 47 with respect to the main body portion 49 is inclined with respect to the main die opening / closing direction A. Also move in direction B. The movement in the lateral direction B is a direction in which the tip end portion of the inclined core 51 is separated from the side wall portion 37 of the bottom 32. As a result, the convex portion 53 of the inclined core 51 comes out of the groove portion 41 of the bottom 32, and the bottom 32 can be taken out without trouble.

By the way, as described above, the inclined core 51 has the bottom.
When moving in the lateral direction B with respect to 32, the second side surface 53b of the groove 41 on the side opposite to the fixed mold 46 is undercut, so that the resin is forcedly removed by elasticity. However, the first side surface 53a of the convex portion 53 of the inclined core 51 on the fixed mold 46 side is directed in the direction in which the inclined core 51 is separated, and the angle α of the first side surface 53a and the angle β of the second side surface 53b. Since α and β have a relationship of α and β, and the convex portion 53 is tapered, the mold releasing resistance of the convex portion 53 as a whole is small. Therefore, the convex portion 53 of the inclined core 51 is surely pulled out from the groove portion 41 of the bottom 32, and the bottom 32 does not come off while sticking to one of the pair of inclined cores 51, and the operation of the inclined core 51 is ensured. Will be things.

Further, in order for the bottom 32 to be smoothly released from the inclined core 51, it is preferable that the angle β of the second side surface 53b which is an undercut is small. This angle β is at most an angle γ formed by the main mold opening / closing direction A and the moving direction C of the inclined core 51.
Should be up to. As a result, the second side surface 53b is not excessively undercut, and the bottom 32 can be reliably released from the inclined core 51.

Further, in terms of the function as the storage case 31 for the mini disc, in the groove portion 41 of the bottom 32, the surface 41b opposite to the base surface portion 36 is inclined toward the back of the groove portion 41 and away from the base surface portion 36. By doing so, the engagement between the claw portion 42 of the lid 33 and the groove portion 41 can be provided with a spring effect, and this engagement state can be ensured. That is, the storage case
In FIG. 31, the lid 32 is larger than the width dimension a of the groove 41 of the bottom 32.
The width dimension b of the claw portion 42 of 33 is slightly increased, so that the surface 41b of the groove portion 41 opposite to the base surface portion 36 and the lid 3 are formed.
The corresponding surface of the claw portion 42 of 3 is elastically pressed by the elasticity of the resin. Therefore, even if only the engagement between the claw portion 42 and the groove portion 41 is performed, it is possible to prevent rattling between the bottom 32 and the lid 33 and separation of the two.

It should be noted that the present invention is not limited to the above embodiment, and various modifications can be made. For example,
In the above embodiment, the product to be molded was the bottom 32 of the storage case 31 for the mini disk, but the present invention can be applied to other products.

[0023]

According to the first aspect of the present invention, a mold apparatus for molding a product having a groove portion with which a claw portion of another product is engaged, on the inner surface side of the side wall portion bent from the end edge of the base surface portion. At
The tilted core incorporated in the second mold to form the groove is the first core on the side of the first mold in the convex portion forming the groove.
The side surface and the second side surface on the opposite side are both inclined toward the tip of the convex portion away from the first mold body with respect to the plane orthogonal to the opening / closing direction of the first mold body and the second mold body. Since the angle formed by the first side surface and the plane orthogonal to the opening / closing direction is larger than the angle formed by the second side surface and the plane orthogonal to the opening / closing direction, the surface of the groove portion opposite to the base surface portion is Despite the undercut, the molded product can be reliably released from the inclined core. Since the surface of the molded product on the side opposite to the base surface portion in the groove portion inclines toward the back of the groove portion and away from the base surface portion, engagement between the groove portion and the claw portion of another product is ensured in terms of product function. Can be certain.

According to the invention of claim 2, in addition to the effect of the invention of claim 1, the angle formed by the second side face and the plane orthogonal to the opening / closing direction is the opening / closing direction and the second mold. Since it is less than the angle formed by the moving direction of the inclined core with respect to the body,
Since the surface of the groove portion on the side opposite to the base surface portion is not excessively undercut, the molded product can be smoothly released from the inclined core.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a mold apparatus of the present invention, showing a mold closed state.

FIG. 2 is a sectional view of the same mold when the mold is opened.

FIG. 3 is a cross-sectional view showing a state in which a bottom and a lid formed by the mold device according to the present embodiment are joined together.

FIG. 4 is a cross-sectional view showing an example of a conventional mold device.

FIG. 5 is a cross-sectional view showing a state in which a bottom and a lid formed by a conventional mold device are joined together.

[Explanation of symbols] 32 Bottom (product) 33 Lid (other product) 36 Base surface part 37 Side wall part 41 Groove part 42 Claw part 46 Fixed type (first mold body) 47 Movable type (second mold body) 51 Tilt Core 53 Convex portion 53a First side surface 53b Second side surface A Main mold opening / closing direction (opening / closing direction of first mold body and second mold body) C Inclined core moving direction α First side face and main mold opening / closing direction are orthogonal Angle formed by the second side surface and the plane orthogonal to the main mold opening / closing direction γ angle formed by the main mold opening / closing direction and the moving direction of the inclined core

Claims (2)

[Claims] 1. A base surface portion and a side wall portion bent from an edge of the base surface portion, and an inner surface side of the side wall portion,
In a mold apparatus for molding a product having a groove portion with which a claw portion of another product is engaged, a first mold body forming an outer surface side of the product and the base surface portion orthogonal to the first mold body. A second mold body that opens and closes in the direction to form the inner surface side of the product, and an inclined core slidably incorporated in the second mold body,
The sliding direction of this inclined core is the same as that of the first mold body and the second mold body.
Is a direction inclined toward the center of the product toward the first mold body side with respect to the opening / closing direction of the mold body, and the inclined core has a convex portion forming the groove portion, and The first side surface on the side of the first mold body and the second side surface on the opposite side are both inclined toward the tip of the convex portion away from the first mold body with respect to the plane orthogonal to the opening / closing direction. The mold device is characterized in that an angle formed by the first side surface and a plane orthogonal to the opening / closing direction is larger than an angle formed by the second side surface and a plane orthogonal to the opening / closing direction. 2. An angle formed by the second side surface and a plane orthogonal to the opening / closing direction is equal to or smaller than an angle formed by the opening / closing direction and a moving direction of the inclined core with respect to the second mold body. The mold device according to claim 1.