JP2671356B2 - Molding equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a molding apparatus in which a resin molding die or the like is provided with an undercut processing mechanism.

b. Conventional Technology Some resin products molded by the injection molding method have a shape called a so-called undercut portion that cannot be released in the opening direction of the mold because of its functional necessity. Since such an undercut part is a part that hinders the removal of the molded product from the mold, when molding this type of resin product, an undercut processing mechanism corresponding to the shape of each undercut part should be used. A molding die that holds the product is required.

As a conventional molding apparatus having an undercut processing mechanism, for example, there is one shown in FIG. That is, the undercut processing mechanism of this molding apparatus includes a nest block 54 which is provided separately from the mold 51 and forms an undercut portion 53 of the resin product 52 together with the mold 51, and the nest block 54. The block 54 includes a drive device 56 that reciprocates in an oblique direction via an inclined slide rod 55. The drive device 56 is an ejector plate 57 that moves in the vertical direction, a slide rail 58 fixed to the ejector plate 57, and A slide block 59 is provided slidably provided in the slide rail 58 and has a lower end portion of an inclined slide rod 55 attached thereto.

Then, in order to release the resin product 52 injection-molded by the molding device, first, the driving device 56 and the inclined slide rod 55 press the nest block 54 in the arrow direction. Then, the insert block 54 pushes up the resin product 52 and moves in a direction away from the undercut portion 53 (right direction in the figure), and accordingly, the undercut portion 53 causes the mold 51 and the insert block 54 to move. Leave from. after that,
A mounting hole 61 for mounting a product is formed in the undercut portion 53 with a machine tool such as a drilling machine.

c. Problems to be Solved by the Invention However, in the above-mentioned conventional molding apparatus,
Since the insert block 54 is driven by the inclined slide rod 55 and the driving device 56, the structure of the undercut processing mechanism is complicated and the number of parts is large, and it is difficult to manufacture the molding device. Further, since the nesting block 54 and the slanting slide rod 55 slidably slide with respect to the vertical pressing force of the drive device 56, a high-strength material is used for the connecting portion between the slanting slide rod 55 and the slide block 59. In addition to the need for manufacturing, the lubricating portion of the drive unit 56 needs to be lubricated regularly, and maintenance of the unit is complicated. In addition to that, in the mold 51 there is an inclined slide rod 55.
A guide hole 60 for guiding the guide must be provided, but since the guide hole 60 is inclined, it is required to perform angle processing with high precision using a large machine tool, which increases the manufacturing cost of the molding apparatus. There was a drawback.

The present invention has been made in view of such circumstances, and an object thereof is to provide a molding apparatus capable of solving the above-mentioned drawbacks.

d. Means for Solving the Problems In order to solve the problems of the above-described conventional technology, in the present invention, in a molding apparatus for molding a resin product having an undercut portion, the molding portion of the undercut portion is a mold. An inclined surface formed by a main body and a nest block, and formed on the mold body and the nest block so as to separate from the undercut portion in the mold opening direction, respectively, and biasing means in the nest block. And a guide long hole is provided, and while the biasing means constantly biases the nest block toward the inclined surface of the mold body, an engaging pin is provided at the tip in the mold body. The ejector rod is inserted through along the mold opening direction, and the tip of the ejector rod is connected to the insert block to release the resin product from the mold body. By moving the ejector rod, the resin product is pushed up from the mold body in the mold opening direction through the nest block, and the nest block is biased by the biasing means and the engaging pin and the long hole. The engaging block is slid along the inclined surface of the mold body so that the nest block is disengaged from the undercut portion.

Hereinafter, the present invention will be described in detail based on illustrated embodiments.

1 and 2 show an embodiment of the present invention, in which 1 is a molding apparatus for injection molding a resin product 2 such as an automobile bumper, and the molding apparatus 1 is a mold body 3
And a mold 4 arranged to face the upper part of the mold body 3.
And an undercut processing mechanism 5 provided on the mold body 3 side. The resin product 2 includes a mold body 3 and a mold 4.
Molded by pouring a molding material such as synthetic resin into a molding space 6 that is closed by closing and, the resin product 2 has an undercut portion 7 serving as a mounting portion, and the undercut portion 7 has a mounting hole 8 Are formed.

The undercut processing mechanism 5 is a nesting block 10 which is fitted in the recess 9 of the mold body 3 so as to be vertically movable.
And a slidable ejector rod 12 inserted into the guide hole 11 of the mold body 3 and an ejector plate 13 for sliding the ejector rod 12 in the mold opening direction (direction of arrow A in the figure). It has. Nesting block 10
The left side surface 14 is provided with a step portion 15, and the left side surface 14 and the step portion 15 and the mold body 3 form a molding portion of the undercut portion 7. And the left side of the nesting block 10
14 is a forming pin 16 which becomes the mounting hole 8 after the resin product 2 is molded.
And the tip end surface of the forming pin 16 is in close contact with the mold body 3 when the resin product 2 is molded. Nesting block 10
Is formed so that the upper surface thereof is flush with the molding surface 3a of the mold body 3 while being housed in the recess 9 of the mold body 3, and constitutes a part of the molding surface 3a.

Further, an inclined surface 17 is formed on the right side surface of the insert block 10 so as to incline outward as it goes upward with respect to the mold opening direction, and the mold body corresponds to the inclined surface 17. An inclined surface 18 inclined in the same direction is also provided in the concave portion 9 of 3. A storage hole 19 formed in a direction orthogonal to the mold opening direction is provided inside the nest block 10, and the nest block 10 is housed in the storage hole 19 on the inclined surface 18 side of the mold body 3 ( A biasing spring 20 that constantly biases in the direction of arrow B in the drawing is housed. For this reason, the biasing spring 20 causes the ejector rod 12 to
It is arranged between the upper end 21 and the lid 22. Further, in the nest block 10, a long guide hole 24 guided by an engagement pin 23 attached to the upper end portion 21 of the ejector rod 12 is bored along a direction orthogonal to the ejector rod 12. The length of the long hole 24 is formed to have a stroke l so that the forming pin 16 can be separated from the mounting hole 8 of the undercut portion 7 when the resin product 2 is released.

On the other hand, the guide hole 11 of the mold body 3 is bored along the vertical direction which is the mold opening direction, and the bush 25 for slidably supporting the ejector rod 12 is fitted in the guide hole 11. There is. Then, the upper end 21 of the ejector rod 12
Is connected to the nest block 10, and the lower end 26 is fixed to the ejector plate 13. Ejector plate
13 is vertically driven by a driving device (not shown).

In the molding apparatus 1 having the above-described configuration, in order to release the resin product 2 after injection molding, first, the mold 4 is separated from the mold body 3 to which the resin product 2 is attached, and the mold is opened. Next, when the ejector plate 13 is lifted in the mold opening direction (the direction of arrow A in the figure), the nest block 10 moves in the same direction via the ejector rod 12 accordingly. As the nesting block 10 moves upward, the resin product 2 becomes a molding surface of the mold body 3.
At the same time as being pushed up by 3a, the nest block 10 itself slides along the inclined surface 18 of the mold body 3 by the biasing force of the biasing spring 20. Then, the insert block 10 moves in the direction of the arrow B along the long hole 24 through the engagement pin 23 by the distance of the stroke l, and the forming pin 16 comes out of the mounting hole 8 of the undercut portion 7 and inserts. The block 10 separates from the undercut portion 7, and the mold release of the resin product 2 is completed (see FIG. 2).

According to the molding apparatus 1 configured as described above, since the biasing spring 20 and the elongated hole 24 are provided inside the nest block 10, and the engaging pin 23 is attached to the tip end portion 21 of the ejector rod 12, the ejector rod By simply moving 12 in the direction of arrow A, the insert block 10 can be pushed up from the mold body 3 in the same direction and moved in the direction of arrow B along the inclined surface 18 of the mold body 3. Become. Also, the nesting block 10
Since the forming pin 16 is protrudingly provided on the left side surface 14 of the, the mounting hole 8 is formed in the undercut portion 7 when the resin product 2 is molded, and the mounting hole 8 is formed in the undercut portion 7 after injection molding as in the conventional case. There is no need to drill holes, and the number of processing steps can be reduced.

As described above, one embodiment of the present invention has been described. However, the present invention is not limited to the above-described embodiment, and various modifications and changes can be made based on the technical idea of the present invention.

For example, the mold opening direction in the above-described embodiment is the upper direction, but it may be the left-right direction. Further, it goes without saying that the shapes of the recess 9 and the nest block 10 of the mold body 3 are not limited to those shown in this embodiment, and can be appropriately selected according to the shape of the resin product 2 to be injection-molded. .

e. Effect of the Invention As described above, in the molding apparatus according to the present invention, when the resin product is released from the mold body, the resin product is moved from the mold body through the nest block by moving the ejector rod. While pushing up in the opening direction, the nest block moves in a direction away from the undercut portion while sliding along the inclined surface of the mold body by the biasing force of the biasing means and the engagement action of the engagement pin and the elongated hole. Since the nest block is separated from the undercut portion, the structure of the mold body and the undercut processing mechanism is simplified, and the molding device can be easily manufactured.
The device manufacturing cost can be reduced. Further, since the molding apparatus of the present invention has a smaller number of parts and sliding parts than the conventional apparatus, maintenance and inspection of the apparatus are easy and excellent in maintainability.

[Brief description of the drawings]

1 and 2 show an embodiment of a molding apparatus according to the present invention. FIG. 1 is a cross-sectional view of a resin product during injection molding, and FIG. 2 is a mold release of the resin product. A sectional view and FIG. 3 are sectional views showing a conventional molding apparatus. 1 ... Molding device, 2 ... Resin product, 3 ... Mold body, 5 ... Undercut processing mechanism, 7 ... Undercut portion, 9 ... Recessed portion, 10 ... Nesting block, 11 ... Guide Hole, 12 ... ejector rod, 13 ... ejector plate, 14 ... left side of nest block, 15 ... step, 17,18 ... inclined surface, 19 ... storage hole, 20 ... bias spring , 21 …… Ejector rod tip, 23 …… Engagement pin, 24 …… Guide long hole, 26 …… Ejector rod lower end.

Claims (1)

(57) [Claims] 1. A molding apparatus for molding a resin product having an undercut portion, wherein the molding portion of the undercut portion is formed by a mold body and a nest block, and the mold body and the nest block are opened. Each of the inclined surfaces is formed so as to be separated from the undercut portion in the direction, and the biasing means and the guiding long hole are provided in the nesting block, and the nesting block is moved by the biasing means. While constantly urging the inclined surface side of the mold body, an ejector rod provided with an engaging pin at the tip is inserted and arranged in the mold body along the mold opening direction, and the tip of the ejector rod is When the resin product is connected to the nest block and the resin product is released from the mold body, the resin product is moved through the nest block by moving the ejector rod. While pushing up in the mold opening direction from the mold main body, the nest block is slid along the inclined surface of the mold main body by the urging force of the urging means and the engaging action of the engaging pin and the long hole. The molding device is configured such that the nest block is separated from the undercut portion.