JP3289665B2 - Injection mold - Google Patents

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 for integrally molding products formed from different molding materials.

[0002]

2. Description of the Related Art Injection molding dies have been devised for integrally molding a product made of a molding material partially different in material. The injection molding dies are formed in a separate process. This reduces the conventional manufacturing burden that has been assembled afterwards. As an example of integrally manufacturing different molding materials, an instrument panel of an automobile shown in FIG. 8 can be cited. The illustrated airbag panel 1 on the passenger seat side is configured such that an airbag cover 3 is provided on an instrument panel main body 2, and when the airbag cover 3 is activated, the airbag cover 3 is broken and inflated to protect a passenger. ing. Therefore, since the airbag cover 3 needs to be formed more fragile than the instrument panel main body 2, for example, as one of the means, the instrument panel main body 2 uses polypropylene resin (PP). The airbag cover 3 is made of olefin-based elastomer (TPO). Both are thermoplastic and co-soluble.

Next, FIG. 9 shows a cross section taken along line MM of FIG. On the surface of the airbag panel 1, there is a groove 11 around the airbag cover 3, and along the groove 11, a thin portion 12 is shown in a range of a broken line S shown in FIG. A part 13 is formed. The overlap portion 14 between the instrument panel 2 and the airbag cover 3 is made of polypropylene resin (PP) and olefin-based elastomer (TP).
It is molded integrally by bonding with O). An airbag 18 that swells by breaking the thin portion 12 of the airbag cover 3 is housed in the airbag cover 3.

Therefore, such a two-color molding method of the instrument panel main body 2 and the airbag cover 3 includes:
This application is disclosed in Japanese Patent Application No. 9-214138 previously proposed by the present application. FIGS. 10A to 10C briefly describe an example of the molding method. First, as shown in FIG. 10 (a), a core slide 103 is provided as a nest in a center block 102 fixed to a core mold 101, and the core slide 103 abuts on a mold mold 111.
Cavity part 121 and second cavity part 122 are divided. Then, first, polypropylene resin (PP) for molding the instrument panel main body 2 is injected into the first cavity portion 121.

Next, as shown in FIG. 10B, the core slide 103 is retracted, and the second
The cavity 122 and the first cavity 121 (the molding material has already been injected) communicate with each other. Therefore, the second
An olefin-based elastomer (TPO) is injected into the cavity 122 and the gap 123. Therefore, FIG.
As shown in the figure, both molding materials (PP, T
PO) is dissolved and adhered, and the instrument panel body 2 and the airbag cover 3 are integrally formed. And
The movable mold part 112 is retracted, and a closed curved groove 11 is formed at the boundary between the instrument panel main body 2 and the airbag cover 3 by its end. After that, core type 1
01 and the mold 111 are released, and the molded product (airbag panel 1) is taken out.

[0006]

According to such an injection molding method, the instrument panel body 2 of the airbag panel 1 and the airbag cover 3 are integrally formed, and a fixture for connecting both members is provided. This has the effect of making it unnecessary. However, the core slide 103 provided to enable such two-color molding abuts on the movable mold part 112 of the mold mold 111 to divide the first cavity part 121 and the second cavity part 122 (FIG. 10).
(A)). Therefore, each time the airbag panel 1 is manufactured, the core slide 103 comes into contact with the mold mold 111 and mold clamping is repeated, and the stress applied each time causes the mold mold 111 (movable mold section 112) to contact with the mold mold 111. The contact surface 113 (see FIG. 10A) is deformed. Therefore,
If the mold 111 that appears as a design surface of a product is deformed, the design surface is deformed or damaged, resulting in a defective product or a reduction in product value.

Accordingly, an object of the present invention is to provide an injection molding die in which the design of a product is not impaired by a core slide in order to solve such a problem.

[0008]

According to the injection mold of the present invention, a core slide movably provided with respect to a core mold is protruded to a mold side, and is formed by the core mold and the mold. The divided space is divided into a first cavity portion and a second cavity portion, and after the first molding material is injected into the first cavity portion, the core slide is retracted and the second molding material is injected into the second cavity portion. Thus, the two molding members are bonded and integrally molded at the communicating portion between the two cavity portions formed by the retreat of the core slide, and when the first molding material is injected into the first cavity portion, the core slurry is formed.
Separation distance between the id and the mold is 0.03-0.05mm
The core slide is positioned in a non-contact state with the mold in the protruding direction.

Therefore, since the core slide and the mold are not in contact with each other during injection molding, the mold does not receive stress from the core slide due to mold clamping. Therefore, the molding surface of the mold for forming the design surface of the product is not deformed, and a product having a good design surface finish can be manufactured. In addition, "core type" corresponds to male type,
The “mold type” corresponds to the female type. The “core slide” is a movable nest.

In addition, the injection mold of the present invention is formed by the core mold and the mold having a core slide movably provided with respect to the core mold in contact with the opposing mold. By dividing the space into a first cavity portion and a second cavity portion and injecting the first molding material into the first cavity portion, by retracting the core slide and injecting the second molding material into the second cavity portion. The two molding members are bonded and integrally molded at the communicating portion of the two cavity portions formed by the retreat of the core slide, and the contact surface of the core slide contacting the mold is made of a material of the mold. Is also characterized by being coated with a soft material, for example, a resin. Therefore, the mold mold does not receive high stress from the core slide due to the mold clamping. Therefore, the molding surface of the mold for forming the design surface of the product is not deformed, and a product having a good design surface finish can be manufactured.

[0011]

Next, a first embodiment of an injection mold according to the present invention will be described with reference to the drawings. Also in the case of the present embodiment, the production of the airbag panel 1 shown in FIG. 8 will be described as an example, and the two-color molding will be described. Therefore, the outline of the injection molding die, particularly the configuration of the die portion, will be mainly described. FIG. 1 shows an injection mold 20 for manufacturing the instrument panel 1.
FIG. This injection molding die 20 includes:
As shown in the figure, the instrument panel 1 is injection-molded in a state where the core mold 21 and the mold mold 31 are in close contact with each other. Specifically, a space formed by the core mold 21 and the mold cavity 31 of the injection mold 20 is a cavity K for injection-molding the instrument panel 1. Except for K, the core mold 21 and the mold mold 31 are in close contact with each other.

In the core mold 21, a core slide 22 which is a nest that can be advanced and retracted is provided. The core slide 22 is formed as an integral type having a hollow cylindrical shape as shown in FIG. 2 according to the shape of the airbag cover 3. FIG. 2 shows that the core slide 22 is a mold 3
It is the figure seen from one side. A center block 23 is loaded in the hollow portion of the core slide 22. The center block 23 and the core slide 22 are independent of each other. The core block 22 is movable within the main mold 24 of the core mold 21, whereas the center block 23 is
It is fixed to.

That is, the core slide 22 is fixed to a block member 25, and the block member 25 is further fixed to a slide member 26. Therefore, the slide member 26, the block member 25, and the core slide 22 are provided as an integral unit, and the slide member 26 and the block member 25 are fixed at a substantially central position of the core slide 22 shown in FIG. On the other hand, the center block 23
Are fixed to the main mold 24 at positions that do not overlap with the block member 25, that is, on both sides inside the core slide 22 via spacer blocks 27 that penetrate the core slide 22 in the moving direction, as shown in FIG. Therefore, the core slide 22 is configured to slide with respect to the main mold 24 and the center block 23 fixed to the main mold 24.

A hydraulic cylinder (not shown) is used to operate the core slide 22, and the position of the core slide 22 can be operated by vertically moving a guide member 28 fixed to the cylinder rod. Guide member 2
Numeral 8 is arranged to move in a direction substantially orthogonal to the core slide 22, and a rail 28 a having a T-shaped cross section is formed on the core slide 22 side at an inclination of a predetermined angle. The slide member 26 fixed to the core slide 22 is attached to the rail 28a.
8a so as to slide without detaching.
The rail 28a and the slide member 26 are in contact with each other on the same sliding surface formed of a tapered surface having the same downward slope.

On the other hand, the mold 31 is provided with a movable part 33 so as to be surrounded by the main mold 32.
Is configured to be able to move within the main mold 32 so that it can be separated from the core mold 21 by a small distance. That is, inside the mold 31, a hydraulic cylinder portion 34 in which a rod extends in a direction substantially perpendicular to the design surface of the molded product (arrow Y3 direction) and a rod in an arrow Y4 direction perpendicular to the arrow Y3 direction are provided. An extended hydraulic cylinder portion 35 is provided. The movable portion 33 includes a step 35A fixed to the tip of the hydraulic cylinder portion 35 and a step 3 behind the movable portion 33.
3A are configured to be positioned by matching each other.

Then, the airbag panel 1 is formed as follows from the injection mold having the injection mold 20 having such a configuration. Here, FIG. 3 and FIG.
FIG. 3 is an enlarged sectional view showing a core mold 21 and a mold mold 31 of a core slide 22 portion. First, as shown in FIG. 1, the core mold 21 and the mold mold 31 are in close contact with each other, and a cavity K for injection-molding the instrument panel 1 is formed. The core slide 22 is moved forward to divide the cavity K into a first cavity K1 for molding the instrument panel body 2 and a second cavity K2 for molding the airbag cover 3.
Protrude. Conventionally, the core slide 22 was positioned in contact with the mold 31, but in the present embodiment, the tip of the core slide 22 does not contact the main mold 32,
Positioning is performed with a small gap m (for example, 0.03 to 0.05 mm).

That is, the guide member 28 of the core slide 22 is moved upward by a hydraulic cylinder (not shown) as shown in FIG.
8a is slid relatively to the right, so that the position of the contact surface between the two moves toward the mold mold 31 side. For this reason, the core slide 22 fixed to the slide member 26 moves to the mold 31 and projects. By the way, as a method for creating a minute gap, for example, a core slide 22 is used.
Corresponds to the moving position of the guide member 28,
It is adjusted by the position of the stopper 29 for positioning the guide member 28a. In addition, it is conceivable that the adjustment is performed by cutting the contact surface of the core slide 22 that is in contact with the mold 31.

When the mold is clamped in such a state, the first mold part 32 of the mold mold 31 and the first cavity portion K1 formed by the core slide 22 and the main mold 24 of the core mold 21 are first molded. As a material, for example, a polypropylene resin (PP), which is a hard synthetic resin, is injected from an injection port (not shown). The minute gap m between the core slide 22 and the main mold 32 is set such that the molten polypropylene resin (PP) injected into the first cavity K1 does not enter the second cavity K2. According to the experiment, a pressure of 40 MPa was applied to the polypropylene resin (P
When P) was injected, good results were obtained with a gap of about 0.03 to 0.05 mm. In addition, as long as the gap is formed, the molding material does not leak at all into the second cavity portion K2. However, the reason why it is described as “good” is from the viewpoint that the finish of the design surface is not impaired.

Then, a molten polypropylene resin (PP) is injected into the first cavity portion K1, and the instrument panel body 2 is formed as shown in FIG. Next, when the guide member 28 is lowered by the hydraulic cylinder, the core slide 22 retreats away from the mold 31. Therefore, when the olefin-based elastomer (TPO) is injected into the second cavity portion K2, the airbag cover 3 is molded so as to overlap a part of the instrument panel body 2, and the molding material (PP) is overlapped at the overlapping portion. , TPO) are dissolved and adhered, and the instrument panel body 2 and the airbag cover 3 are integrally formed.

Thereafter, in the mold 31, the pressing portion 34 A of the hydraulic cylinder portion 34 in the main mold 32 shown in FIG.
The step 35A at the tip of the hydraulic cylinder 35 is retracted in the direction of the arrow Y4 while the movable mold 33 is pressed and supported on the core mold 21 side. The step 35 at the tip of the hydraulic cylinder 35
When a predetermined gap is formed between A and the step portion 33A behind the movable mold portion 33, the movable mold portion 33 is retracted by the hydraulic cylinder portion 34 in the arrow Y3 direction to be separated from the molded product. Then, the core mold 21 and the mold mold 31 are moved to the left and right in the drawing to be separated from each other, and the molded airbag panel 1 is pushed by the protrusion pins (not shown).
After being removed from the side, it is taken out by, for example, a robot arm (not shown).

As described above, according to the injection mold of the first embodiment, since the core slide 22 is not in direct contact with the mold 31 and is in a non-contact state, the mold 31 for molding the design surface of the product is formed. The surface of the (movable mold portion 33 and the main mold 32) is no longer pressed against the core slide 22 by the mold clamping and deformed. Therefore, a product with a good design surface can be manufactured by repeated manufacturing of a molded product. In addition, since the core slide 22 is not in contact with the mold 31, it is not necessary to replace the mold 31 which has been replaced each time the design surface is deteriorated due to deformation of the mold. The life of the 20 itself has been extended. This reduces the cost of the mold, which is a very expensive part, and also reduces the cost of the product. Further, since such an effect on the design surface can be achieved with a simple configuration, it also contributes to cost reduction of products.

Next, a second embodiment of the injection mold according to the present invention will be described with reference to the drawings. However,
The configuration is substantially the same as that shown in FIG. 1, and therefore, is denoted by the same reference numeral, and only the characteristic portions will be described. FIG. 5 is an enlarged cross-sectional view of the core mold 21 and the mold 31 of the core slide 22 in the injection mold according to the present embodiment. The injection mold according to the present embodiment has a problem in that the surface of the mold 31 to which the core slide 22 abuts is deformed by mold clamping. The solution is achieved by coating with a soft material. Therefore, the tip 22A of the core slide 22 is coated with a soft epoxy resin or the like to a thickness of about 1 to 2 mm on the mold 31 made of a metal material such as S50C.

Therefore, according to the injection molding die of the present embodiment, the core slide 22 is formed of the mold 31 (in FIG. 5,
Even when the core slide 22 is directly applied to the main mold 32, high stress is not applied to the portion where the core slide 22 is pressed by the mold clamping. Accordingly, deformation of the mold 31 due to mold clamping is avoided, and a product having a design surface with a good finish can be manufactured by repeated manufacturing. In addition, since the contact surface of the core slide 22 is coated, it is not necessary to replace the mold 31 which has been replaced each time the design surface is deteriorated due to deformation of the mold, and the life of the injection mold 20 itself is reduced. Has grown. this is,
Cost reduction for molds, which are very expensive parts,
As a result, the cost of the product will be reduced. In addition, the cause which had a bad influence on the design of the product in the past can be solved with an extremely simple configuration.

Next, a third embodiment of the injection mold will be described with reference to the drawings. The injection molding die of the present embodiment also has a core slide in a core die. FIGS. 6 and 7 show enlarged cross-sectional views of the core die and the mold of the core slide portion. The mold for injection molding according to the present embodiment is configured to move the core slide 22 so that the surface of the mold 31 to which the core slide 22 abuts is deformed by clamping, so that the two are not in contact with each other. The solution is achieved by adjusting. Therefore, similarly to the first embodiment, the core slide is brought into non-contact with the mold to prevent deformation of the mold. Further, the injection molding die of the present embodiment is characterized in that the design surface is molded with a single molding material even in the case of two-color molding.

Therefore, the injection mold of the present embodiment is
As shown in FIG. 6, the core slide 41 is formed as a single block, and is provided so as to move in the core mold main die 42 in a direction perpendicular to the molding surface, and is fixed to a hydraulic cylinder or the like, for example. . On the other hand, a movable mold portion 52 is provided in the mold main mold 51. A protrusion 52 </ b> A is provided on the peripheral edge of the movable mold portion 52 so as to form a thin portion for breaking and expanding the airbag cover when the airbag is activated.

Therefore, in the injection mold according to the present embodiment, the core mold and the mold mold are in close contact with each other, and as shown in FIG. 6, the first cavity portion K11 for molding the instrument panel body. Is formed. In this state, the second cavity for forming the airbag cover has not yet appeared. By the way, also in the present embodiment, the core slide 41 is positioned so as not to contact the mold.
However, the gap P with the movable mold part 52 of the mold type is separated by a predetermined distance so that the airbag cover portion is formed of the same material as the instrument panel body and made of thin polypropylene resin (PP). I have. On the other hand, the main mold 42 and the core slide 41 are separated by a small gap S (for example, about 0.03 to 0.05 mm) so that the polypropylene resin (PP) does not flow into the rib space K12. . Therefore, when the polypropylene resin (PP) is injected into the first cavity portion K11, the entire surface of the airbag panel is molded. That is, the surface of the airbag cover is also made of polypropylene resin (PP)
To form a thin layer.

Next, the core slide 4 is moved to the position shown in FIG.
The cavity portion expands due to the retraction of 1, and the olefin elastomer (TPO) is injected into the expanded portion and the rib space portion K12 that can flow. Therefore, in the present embodiment, since the surface of the airbag cover 62 is molded integrally with the polypropylene resin (PP) similarly to the instrument panel main body 61, there is no boundary between different molding materials, and the appearance is improved. Got well. In addition, since the core slide 41 does not abut against the mold, deformation of the mold due to mold clamping can be prevented, and the quality of the design surface of a repeatedly manufactured product can be continuously maintained.

The injection mold according to the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above-described embodiment, the injection molding die for manufacturing the instrument panel with the airbag cover of the vehicle has been described as a molded product, but other two-color or more multi-color molding is required. It can be applied to various products as needed. The distance of the gap m between the core slide 22 and the mold 31 shown in the first embodiment can be appropriately changed in design according to a molded product or a molding material.

The soft material coated on the contact surface 22A of the core slide 22 in the second embodiment is as follows:
For example, rubber or the like may be used instead of the resin material. Further, in the third embodiment, the movement of the core slide 41 is set in two steps in order to perform injection molding with two layers, but it may be set in more steps. In the above embodiment, two different types of molding materials (polypropylene resin and olefin-based elastomer) are used, but in other embodiments, three or more types of different materials may be used, Further, the first material and the second material may be the same material.

[0030]

According to the present invention, a core slide provided movably with respect to a core mold is protruded toward a mold side, and a space formed by the core mold and the mold is divided into a first cavity portion and a second cavity portion. After splitting into two cavities and injecting the first molding material into the first cavity, the core slide is retracted and the second molding material is injected into the second cavity to form the core slide by retreating The two molding members are bonded and integrally molded at the communicating portion of the two cavity portions, and when the first molding material is injected into the first cavity portion, the separation distance between the core slide and the mold is reduced.
Since the core slide is positioned so as to be 0.03 to 0.05 mm in a non-contact state with the mold in the projecting direction, the mold is not deformed by the core slide, and the design surface of the product is damaged. It has become possible to provide a mold for injection molding that does not have any problems.

Further, according to the present invention, a core slide movably provided with respect to a core mold is brought into contact with an opposing mold, and a space formed by the core mold and the mold is filled in the first cavity portion. After the first molding material is injected into the first cavity portion, the core slide is retracted, and the second molding material is injected into the second cavity portion. The two molding members are adhered to each other at the communicating part of the two cavity parts formed by molding, and the contact surface of the core slide contacting the mold is coated with a material softer than the material of the mold. With this configuration, it is possible to provide an injection mold that does not deform the mold due to the core slide and does not impair the design surface of the product.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an injection mold 20 according to a first embodiment.

FIG. 2 is a view of the core slide 22 viewed from the mold 21. FIG.

FIG. 3 is an enlarged cross-sectional view of a core mold 21 and a mold mold 31 of the injection mold according to the first embodiment.

FIG. 4 is an enlarged cross-sectional view of a core mold 21 and a mold mold 31 of the injection mold according to the first embodiment.

FIG. 5 is an enlarged cross-sectional view of a core mold 21 and a mold mold 31 of the injection mold according to the second embodiment.

FIG. 6 is an enlarged sectional view of a core mold and a mold of an injection molding die according to a third embodiment.

FIG. 7 is an enlarged sectional view of a core mold and a mold of an injection mold according to a third embodiment.

FIG. 8 is a perspective view showing an instrument panel of an automobile.

FIG. 9 is a diagram showing a cross section taken along line MM of FIG. 8;

FIG. 10 is a diagram illustrating an example of a two-color molding method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Airbag panel 2 Instrument panel main body 3 Airbag cover 20 Injection mold 21 Core mold 22 Core slide 31 Cabinet mold 33 Movable mold part m Gap K1 First cavity part K2 Second cavity part

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-10-291232 (JP, A) JP-A-62-116122 (JP, A) JP-A-7-330055 (JP, A) JP-A 5- 220793 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 45/00-45/84

Claims (3)

(57) [Claims] 1. A core slide movably provided with respect to a core mold is projected to a mold side, and a space formed by the core mold and the mold is divided into a first cavity portion and a second cavity portion. After injecting the first molding material into the first cavity portion, the core slide is retracted, and the second molding material is injected into the second cavity portion, so that both cavities formed by retreating the core slide be one integrally molded by bonding the two molded members in the communicating portion of the parts, when injecting a first molding material into the first cavity portion, co
The distance between the slide and the mold is 0.03 to 0.0
An injection molding die for positioning a core slide so as to be 5 mm in a non-contact state with a mold in a projecting direction. 2. A core provided movably with respect to a core mold.
Aslide is brought into contact with the opposite mold, and its core
The space formed by the mold and the mold
Divided into a cavity part and a second cavity part, and the first cavity part
After injecting the first molding material, retract the core slide
By injecting the second molding material into the second cavity,
Both cavities formed by the retreat of the core slide
The two molded members are bonded together at the communication part of the
And the contact surface of the core slide contacting the mold with the mold
Characterized by coating with a softer material than the material of
Mold for injection molding. 3. The injection mold according to claim 2, wherein :
Te, coated lower subsidiary an abutment surface of the core slide resin
And a mold for injection molding.