JPH04312809A - Mold for molding - Google Patents

Abstract

PURPOSE:To provide a mold for molding capable of preventing the occurrence of flashes and maintaining the long life of the mold in regard of a mold for molding a frame member arranged with holes in its surface plate part. CONSTITUTION:The construction is characterized by providing a hole pin 35 that is mounted on a movable half of mold 20 and projected from the hole of a core 21 through mold clamping for piercing the part corresponding to the hole 3 of a molding 1 and then tightly fitted in its tip into a faucet hole 40 provided on the cavity 11 of a front mold 10, guide pin 36 provided such that the axial core is made to coincide with the tip of the hole pin 35, and a guide hole 41 in which the guide pin 36 provided on the cavity 11 is fitted.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for forming a housing having holes arranged in its surface plate. 2. Description of the Related Art Housings for terminal devices such as electronic devices and communication devices are required to be lightweight and low-cost, so they have conventionally been manufactured from synthetic resin by injection molding or the like.

[0002] A molded product 1 shown in FIG. 3 is a casing for the above-mentioned terminal device, and consists of an upper casing and a lower casing that are molded separately at the chain line A-A. The portion 2 is a curved surface, and holes 3 into which operating parts such as keys are fitted are arranged in the surface plate portion 2.

FIG. 4 shows a mold for molding the above-mentioned molded product 1 (upper casing). In Figure 4, the mold includes a sprue, runner, and gate (all not shown).
The fixed mold 10 includes a cavity 11 and the like, and the movable mold 20 includes a core 21, an ejector pin 25, a hole pin 35, a slide core 34, and the like.

To be more specific, the fixed side mold 10 has a fixed side mounting plate 13 that is attached to a fixed die plate of a molding machine, and a fixed side mounting plate 1 that has a flat surface opposite to the parting surface A-A.
3, and a cavity 11 which has a sprue and a runner at its axis and is mounted in the center of the support plate 12.

[0005] In the stationary mold 10, a guide bush 32, into which a guide pin 31 mounted on the movable mold side fits snugly, is inserted into the support plate 12. On the other hand, the movable mold 20 includes a movable mounting plate 23 attached to a movable die plate of a molding machine, and a parting surface A.
- The flat surface opposite to A is the backing plate 24,
Movable side mounting plate 23 via spacer block 24A
It has a support plate 22 fixed to the support plate 22 and a core 21 attached to the center of the support plate 22.

[0006]The ejector plate is inserted into a space surrounded by the movable side mounting plate 23, the spacer block 24A, and the backing plate 24. The ejector pin 25, which passes through the small hole of the core 21 and has its tip exposed to the parting surface, has its root portion fixed to the ejector plate.

On the other hand, there is a wedge-shaped slide core 3 whose back surface is in close contact with the backing plate 24 and whose surface on the core 21 side is inclined.
4 is attached to the movable mold 20 so as to be slidable in a direction perpendicular to the mold clamping direction. And slide core 34
An angler pin 33 passing through the inclined hole is fixed to the backing plate 24.

38 is a rectangular holder block that holds the hole pin 35 so that the tip of the hole pin 35 protrudes from the tip surface, and its bottom surface is aligned with the axis of the hole pin 35. It is tilted.

The holder block 38 is inserted into the square hole of the core 21 so as to be movable back and forth so that the bottom surface slides on the inclined surface of the slide core 34. Note that the hole pin 35 is configured to fit snugly through the hole of the core 21 and protrude toward the cavity 11.

[0010] In order to mold the molded product 1 using the above-mentioned mold, first move the movable mold 20 toward the fixed mold 10 and bring the parting surfaces A-A of both parts into close contact. Close the mold.

Along with this mold closing movement, the angler pin 3
3, the slide core 34 moves forward toward the center of the movable mold 20. As a result, the inclined surface of the slide core 34 pushes up the bottom surface of the holder block 38. When the holder block 38 is pushed up, the hole pin 35 protrudes into a position corresponding to the hole 3 of the molding cavity of the desired shape formed by the cavity 11 and the core 21.

On the other hand, at the same time as the mold closing is completed, the molten resin is press-fitted into the sprue, and the molten resin is press-fitted and filled into the molding cavity of the desired shape formed by the cavity 11 and the core 21 through the sprue, runner, and gate. do. As a result, a molded article 1 having a desired shape is molded.

[0013] At this time, since the hole pin 35 protrudes into a portion corresponding to the hole 3 of the molding cavity, a hole 3 having the same external shape as the hole pin 35 is formed in the molded product 1. . After the molten resin is press-fitted and a predetermined time has elapsed, the movable mold 20 is moved back and the mold is opened. At this time, the molded product 1 adheres to the core 21, retreats, and is separated from the stationary mold 10.

Near the end of the retraction of the movable mold 20, the ejector attached to the molding machine hits the ejector plate, and the ejector plate, that is, the ejector pin 25 moves forward, and the tip of the ejector pin 25 touches the parting of the core 21. protrude from the surface.

[0015] Therefore, the molded product 1 falls off from the movable mold 20, and the molded product 1 is taken out from the mold. In the molded product 1 formed as described above, a key button is incorporated into the hole 3 provided in the surface plate portion 2.

At this time, if burrs are generated on the peripheral edge of the hole 3 during molding, the key button will not return to its original position. Therefore, a mold that does not generate burrs is required.

[0017]

[Prior Art] Fig. 5 is a diagram of a conventional example, (A) is a sectional view of important parts of a mold, (B) is a sectional view of important parts of a molded product, and Fig. 6 is a diagram of another conventional example. ) is a cross-sectional view of key points of the mold, and (B) is a cross-sectional view of key points of the molded product.

In FIG. 5, the holder block 38 is inserted into the square hole of the core 21 so as to be movable back and forth so as to slide on the inclined surface of the slide core 34, and is passed through the hole of the core 21.
A hole pin 35 that penetrates the part corresponding to the hole 3 of the molded product 1
is made to protrude from the distal end surface of this holder block 38.

Then, when the mold is closed, the hole pin 35
The distal end surface is strongly abutted against the inner surface of the cavity 11 to bring it into contact. In FIG. 6, the holder block 38 is inserted into the square hole of the core 21 so as to be movable back and forth so as to slide on the inclined surface of the slide core 34, and is passed through the hole of the core 21, corresponding to the hole 3 of the molded product 1. A hole pin 35, which penetrates through the portion where the holder block 38 is inserted, protrudes from the front end surface of the holder block 38.

Then, when the mold is closed, the hole pin 35
The distal end of the spigot is tightly fitted into a spigot hole 40 provided in the cavity 11.

[0021]

[Problems to be Solved by the Invention] By the way, as shown in FIG. 5, a mold in which the tip end surface of the hole pin 35 is brought into contact with the inner surface of the cavity 11 has no gap on the parting surface and the mold is completely closed. In this state, it is difficult to bring the tip end surface of the hole pin 35 into contact with the inner surface of the cavity 11 without a gap due to the dimensional accuracy of the slide core 34, holder block 38, and hole pin 35.

Particularly when the hole 3 is present on the curved surface of the surface plate portion 2, it is extremely difficult to bring the tip end surface of the hole pin 35 into contact with the inner surface of the cavity 11 without any gaps. Therefore, as shown in FIG. 5B, a horizontal burr 5A is generated on the upper edge of the hole 3 toward the center. That is, the conventional mold shown in FIG. 5 has a problem in that the horizontal burrs 5A occur, which impairs the operation of the key button installed in the hole 3.

Although burrs on thermosetting resins can be removed relatively easily, thermoplastic resins are widely used as resins for injection molding, and burrs on thermoplastic resins are flexible. Not easy to remove.

In the conventional example shown in FIG. 6, the tip of the hole pin 35 is fitted into the spigot hole 40 of the cavity 11, so burrs are less likely to occur. If there is a gap between the hole pin 35 and the pilot hole 40, a horizontal burr does not occur, but a vertical burr 5B as shown in FIG. 6(B). This vertical burr 5B does not interfere with the operation of the key button attached to the hole 3 as much as the horizontal burr.

However, it is required that the fixed side mold and the movable side mold have high fitting accuracy, and if this fitting accuracy is poor, the hole pin 35 will collide with the edge of the spigot hole 40 and the cavity will be damaged. There was a problem that 11 was damaged.

The present invention was created in view of the above points, and an object of the present invention is to provide a mold that prevents the occurrence of burrs and has a long mold life.

[0027]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a movable mold 20 as illustrated in FIG.
By attaching the hole pin 35 to the mold and closing the mold, it is pushed out from the hole of the core 21 and passes through the part corresponding to the hole 3 of the molded product 1, and the tip is installed in the cavity 11 of the stationary mold 10. A guide pin 36 is provided so that the guide pin 36 is tightly fitted into the spigot hole 40 , and its axis coincides with the tip of the hole pin 35 . It is configured to fit into a guide hole 41 provided in the cavity 11.

Further, as illustrated in FIG. 2, a bush 45 is removably attached to the cavity 11 of the stationary mold 10, and a guide hole 41 provided at the axis of the bush 45 is inserted into the cavity 11 of the stationary mold 10.
The structure is such that a hole pin 35 is inserted therein.

[0029]

[Function] As described above, the present invention has a guide pin 36 whose axis coincides with the tip of the hole pin 35 attached to the movable mold 20, and this guide pin 36 is arranged so that the hole pin 35 is aligned with the cavity. Prior to fitting into the pilot hole 40 of No. 11, it is fitted into the guide hole 41.

Therefore, even if the precision of fitting between the stationary mold and the movable mold is not high, the hole pin 35 fits snugly into the spigot hole 40. That is, even if the internal dimensions of the spigot hole 40 are almost equal to the external dimensions of the hole pin 35, the end surface of the hole pin 35 will not fit into the spigot hole 40 when the mold is closed.
This eliminates collisions with the edges of the mold, which not only extends the life of the mold, but also almost eliminates vertical burrs.

On the other hand, by removably providing the guide hole 41 into which the guide pin 36 fits into the bush 45, it is possible to prevent the guide pin 36 from colliding with the edge of the guide hole 41 and damaging the guide hole 41. , just replace the bush 45. That is, the mold of the present invention is easy to maintain.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail below with reference to the drawings. Note that the same reference numerals indicate the same objects throughout the figures.

FIG. 1 is a sectional view of an embodiment of the first invention, and FIG. 2 is a sectional view of an embodiment of the second invention. In FIG. 1, the molding die consists of a fixed die 10 and a movable die 20. A
- The support plate 12 whose flat surface opposite to A is fixed in close contact with the fixed side mounting plate 13, and the sprue and runner (
(none of which are shown), and a cavity 11 that is attached to the center of the support plate 12.

On the other hand, the movable mold 20 includes a movable mounting plate (not shown) that is attached to a movable die plate of a molding machine, etc.
A supporting plate 22 whose flat surface opposite to the parting surface A-A is fixed to the movable side mounting plate via a backing plate 24 and a spacer block (not shown);
It has a core 21 attached to the center of the.

On the other hand, there is a wedge-shaped slide core 3 whose back surface is in close contact with the backing plate 24 and whose surface on the core 21 side is inclined.
4 is attached to the movable mold 20 so as to be slidable in a direction perpendicular to the mold clamping direction, and the inclined hole 33A of the slide core 34
An angler pin 33 passing through is fixed to the backing plate 24.

The inclined bottom surface of the rectangular holder block 38 that holds the hole pin 35 is slid on the inclined surface of the slide core 34 so that the tip of the hole pin 35 protrudes from the tip surface. It is inserted into a square hole of the core 21 so as to be movable back and forth.

Further, the hole pin 35 is connected to the hole 21A of the core 21.
A guide pin 36 is provided so that the shaft center thereof coincides with the tip of the hole pin 35.

[0038] Furthermore, the cavity 11 on the fixed side mold 10 side
, a hole pin 35 is placed at a position corresponding to the hole 3 of the molded product 1.
The pilot hole 4 into which the tip of the hole pin 35 is tightly fitted
0, and a guide hole 41 into which the guide pin 36 is fitted is provided at the deep bottom (upper part in the figure) of the pilot hole 40 so as to coincide with the axis of the pilot hole 40.

The above-mentioned hole pin 35 is projected from the hole of the core 21 when the mold is closed, passes through a portion corresponding to the hole 3 of the molded product 1, and its tip end connects to the spigot hole 40 provided in the cavity 11. to fit tightly into the and guide pin 36
is sized and shaped so that the hole pin 35 fits into the guide hole 41 before fitting into the spigot hole 40.

Therefore, in the mold shown in FIG. 1, even if the inner dimension of the pilot hole 40 is almost equal to the outer dimension of the hole pin 35, the end surface of the hole pin 35 is not connected to the pilot hole when the mold is closed. Collision with the edge of the hole 40 is eliminated. In other words, not only are there almost no vertical burrs, but the mold has a long life.

In FIG. 2, a pilot hole 40 into which the tip of the hole pin 35 attached to the movable mold 20 is fitted is provided in the cavity 11 of the stationary mold 10, and a pilot hole 40 is provided on the extension line of the pilot hole 40. A hole is provided, and a bush 45 is inserted into this through hole. The axial center hole of this bush 45 serves as a guide hole 41 into which the guide pin 36 is fitted. Further, the upper part of the guide hole 41 is a screw hole into which a screw 46 is screwed.

On the other hand, a hole is bored in the back side of the support plate 12 of the stationary mold 10, and a presser plate 47 is fitted into this hole.
By embedding a screw 46 in 7 and screwing the threaded portion into the aforementioned screw hole of the bush 45, the bush 45 is prevented from falling off.

Note that the back side of the presser plate 47 is attached to the fixed side mounting plate 1.
3 to prevent the presser plate 47 from coming off. Since the bush 45 is attached to the stationary side mold 10 as described above, if the tip of the guide pin 36 collides with the edge of the guide hole 41 and the guide hole 41 is damaged, the stationary side mounting plate 13 By removing the screw and then loosening the screw 46,
Bush 45 can be replaced. That is, this mold is easy to maintain.

[0044]

[Effects of the Invention] As explained above, in the present invention, when making holes in a molded product, a hole pin is attached to the movable mold side,
A mold with a guide pin provided at the tip of the hole pin so that when the mold is closed, the guide pin fits into the guide hole on the cavity side before the hole pin fits into the spigot hole of the cavity. This eliminates the possibility of the end face of the hole pin colliding with the edge of the spigot hole, which not only prolongs the life of the mold, but also has the excellent effect of almost no burrs occurring around the hole of the molded product. .

Furthermore, since the bush provided with the guide hole can be easily replaced, maintenance of the mold of the present invention is easy.

[Brief explanation of drawings]

[Fig. 1] Cross-sectional view of the embodiment of the first invention

[Figure 2]
Cross-sectional view of the embodiment of the second invention

[Figure 3] Cross-sectional view of molded product

[Figure 4] Cross-sectional view of the mold

[Figure 5] A diagram of a conventional example, (A) is a cross-sectional view of key points of the molding die, and (B) is a cross-sectional view of key points of the molded product.

[Figure 6] Another conventional example in which (A) is a cross-sectional view of key points of the molding die and (B) is a cross-sectional view of key points of the molded product.

[Explanation of symbols]

Claims (2)

[Claims] Claim 1: It is attached to the movable mold (20), and when the mold is closed, it is ejected from the hole of the core (21) and penetrates the part corresponding to the hole (3) of the molded product (1), A hole pin (35) whose tip part fits tightly into the pilot hole (40) provided in the cavity (11) of the stationary mold (10).
, a guide pin (36) provided so that its axis coincides with the tip of the hole pin (35), and a guide hole (41) into which the guide pin (36) provided in the cavity (11) is fitted.
A mold characterized by the following. 2. A bushing in which a guide hole (41) into which a hole pin (35) attached to a movable mold (20) is fitted is removably embedded in a cavity (11) of a fixed mold (10). The mold according to claim 1, characterized in that it is provided in (45).