JP3298742B2 - Method for preventing deformation during instrument panel molding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing deformation of an instrument panel of an automobile, which is caused by molding shrinkage of the instrument panel when the panel is removed after injection molding with a mold.

[0002]

2. Description of the Related Art An example of an instrument panel of an automobile will be described with reference to FIG. The instrument panel 1 is a horizontally elongated resin molded product having an undercut structure, and has a rectangular cylindrical air outlet 1a at both lateral ends. As shown in FIG. 10, the air outlet 1a has a circular mounting hole 2 penetrating through opposing portions of the upper and lower wall surfaces of the air outlet 1a in order to rotatably accommodate the register 8 as a wind direction changing component. As shown by the dashed line in FIG. 10, the register 8 housed in the air outlet 1a has a pivot (not shown) protruding from the upper and lower surfaces thereof inserted into the mounting hole 2 so that the inside of the air outlet 1a can be opened. Is mounted so as to be rotatable around the mounting hole 2.

[0003] The instrument panel 1 is injection-molded with a metal mold, and then subjected to a demolding process using a movable inclined extrusion die having an air outlet port 1a. A specific example will be described with reference to FIGS. FIG. 11 is a cross-sectional view of a mold before injection molding of the instrument panel 1 and before a demolding process. The movable mold 6 for molding the peripheral portion of the air outlet 1a of the instrument panel 1 is provided in the mold shown in FIG. , Air outlet 1a
Is shown. The movable die 6 is formed with a rectangular opening 10 corresponding to the air outlet portion 1a, and the outlet die 3 is installed in the opening 10 so as to be able to come and go. The outer peripheral surface of the air outlet 1a is formed by the opening 10, and the inner peripheral surface of the air outlet 1a and the mounting hole 2 are formed by the outlet die 3.

The outlet mold 3 includes a pair of upper and lower extrusion dies 4 and an extrusion die guide 5 located between the pair of upper and lower extrusion dies 4 for vertically opening and closing the upper and lower extrusion dies 4. The upper and lower surfaces of the extrusion die guide 5 are tapered surfaces that become narrower toward the rod tip, and the inner surfaces of the upper and lower extrusion dies 4 are also tapered corresponding to the tapered surfaces. The extrusion die guide 5 is fixedly connected to the movable die 6, and when the upper and lower extrusion dies 4 protrude from the extrusion die guide 5 during the demolding process, the upper and lower extrusion dies 4 approach each other due to the mutual tapered surfaces. When the upper and lower extruding dies 4 move in and out of the extruding die guide 5 on the contrary, the upper and lower extruding dies 4 perform an opening operation in which the upper and lower extruding dies 4 are separated from each other by their tapered surfaces.

As shown in the sectional view of FIG. 12, upper and lower extrusion dies 4 have circular projections 4 on the outer surface opposite to the inner surface of the taper.
a. The tip of the projection 4a is the opening 1 of the movable die 6.
The mounting hole 2 is formed in the upper and lower wall surfaces of the air outlet portion 1a by the protrusions 4a in contact with the inner surface of the air outlet port 1a.

[0006] Injection molded instrument panel 1
Is performed as shown in FIG. From the state shown in FIG.
Performs a protruding operation with respect to. Mounting hole 2 for air outlet 1a
The instrument panel 1 is pushed out of the movable mold 6 by the projecting operation of the extrusion mold 4 by the engagement of the projection 4a of the extrusion mold 4 with the projection 4a. The upper and lower extrusion dies 4 perform a closing operation approaching each other as they protrude, and when they protrude a predetermined amount, as shown in FIG.
The protrusions 4 a of the upper and lower extrusion dies 4 are detached from the mounting holes 2. At this stage, the removal of the instrument panel 1 is completed, and the instrument panel 1 is taken out.

[0007]

The injection-molded instrument panel 1 undergoes molding shrinkage upon cooling after molding. This molding shrinkage occurs toward the center of the instrument panel 1 as shown by the arrow direction in FIG. 9, and since the instrument panel 1 is horizontally long, the shrinkage tensile force or the amount of shrinkage movement at both right and left ends is particularly large. . This contraction movement
This occurs when the instrument panel 1 is extruded by the extrusion die 4. Therefore, the mounting hole 2 of the air outlet 1a is often deformed in the process shown in FIGS. 14 (a) to 14 (c).

That is, before the instrument panel is pushed out, as shown in FIG. 14A, the projection 4a of the extrusion die 4 is in a state of being fitted into the entire mounting hole 2 of the air outlet 1a. In this state, the instrument panel 1 attempts to shrink in the direction of the arrow in FIG. 14, but at this time, the air outlet 1a is still in the outlet die 3, and the projection 4a receiving the molding shrinkage force F Since the engagement area of the mounting hole 2 is large, the mounting hole 2 is not deformed. When the extruding die 4 is caused to protrude and the instrument panel 1 is extruded from the movable die 6, the projection 4 a moves in a direction to come out of the mounting hole 2 by the closing operation of the pair of extruding die 4.

FIG. 14B shows a state in which the projection 4a has been pulled out to about half of the mounting hole 2, and FIG.
2 shows a state immediately before exiting from the mounting hole 2. FIG.
In the stage from (b) to (c), the engagement area between the mounting hole 2 and the projection 4a that receives the molding contraction force F of the instrument panel 1 decreases, and the strength of the mounting hole 2 is reduced by the molding contraction force F.
As shown in FIG. 14 (c), the edge 2 ′ of the mounting hole 2 may be crushed by the tip of the projection 4a.

As shown in FIG. 14 (c), when the mounting hole 2 of the air outlet 1a of the instrument panel 1 is deformed, the appearance of the instrument panel 1 deteriorates and the air as shown by the chain line in FIG. There is a problem that the pivot of the register 8 attached to the outlet 1a is loose in the mounting hole 2 and the fitting and operability of the register 8 are deteriorated, so that the commercial value of the instrument panel 1 is reduced.

An object of the present invention is to provide a molding method for preventing deformation of an instrument panel mounting hole due to molding contraction of an instrument panel after injection molding.

[0012]

SUMMARY OF THE INVENTION The present invention relates to an undercut structure of a resin instrument panel having an undercut structure having an air outlet formed with mounting holes for supporting external parts at upper and lower walls. The inner surface is located between a pair of upper and lower extrusion dies and a pair of upper and lower extrusion dies that integrally project a projection that forms a mounting hole, and the upper and lower extrusion dies approach vertically by relative movement back and forth with the extrusion dies. After forming the outer surface of the air outlet portion and its peripheral portion with a movable die, the instrument panel is extruded from the movable die with the upper and lower extrusion dies of the air outlet type. A method for preventing deformation of the mounting hole of the instrument panel in the injection molding process of the instrument panel, wherein the protrusions of the upper and lower extrusion dies are detached from the mounting hole of the air outlet.
In the vicinity of the protrusion of the extrusion die, a protrusion is integrally provided on the surface of the extrusion die adjacent to the protrusion of the extrusion die in the molding contraction direction of the injection-molded instrument panel, and the air of the instrument panel is formed by the protrusion. A concave portion is formed in the vicinity of the mounting hole of the blow-out portion, and a molding contraction force of the instrument panel when the injection-molded instrument panel is released from the extrusion die is used as an engagement portion between the projection and the mounting hole, and a convex portion. And the engaging portion of the concave portion.

[0013]

The extruding projection forms a mounting hole for the air outlet of the instrument panel, and the projection provided adjacent to the projection forms a recess near the mounting hole of the air outlet for injection. The molding contraction force of the instrument panel when the molded instrument panel is released from the extrusion die is dispersed and applied to the engaging portion between the projection and the mounting hole, and the engaging portion between the convex portion and the concave portion. The molding shrinkage force applied to the mounting hole is reduced, and the deformation of the mounting hole is prevented.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of the present invention will be described below with reference to specific embodiments of FIGS. 1 to 7. The embodiment of FIG. 1 is for injection-molding the instrument panel 1 of FIG.
The same or corresponding parts as those in FIGS. 10 to 14 are denoted by the same reference numerals.

In the present invention, as shown in FIGS. 1 to 3, a pair of upper and lower extrusion dies 4 of the air outlet die 3 are integrally provided with a projection 4a and a projection 4b in the vicinity thereof. This structure is exactly the same for the upper and lower extrusion dies 4. The protrusions 4 b are formed, for example, as a pair on both sides of the protrusion 4 a in the molding contraction direction of the injection-molded instrument panel 1, that is, in the left-right direction of the instrument panel 1. The height of the protrusion 4b may be the same as that of the protrusion 4a, but is set slightly lower than the protrusion 4a as shown in FIG. The shape of the convex portion 4b may be arbitrary, but FIG. 2 shows a rectangular shape slightly longer than the diameter of the circular protrusion 4a, and a shape in which the long side surface faces the protrusion 4a.

Further, a part of the leading edge of the projection 4a is chamfered to form a tapered surface m, and an inclined bulging portion 4c corresponding to the tapered surface m is formed at a part of a root portion of the projection 4a. This is desirable for the reasons described below. Tapered surface m of projection 4a
Is formed at the tip end of the projection in the direction opposite to the molding contraction direction of the instrument panel 1, and the inclined bulging portion 4c is formed at a position directly below the tapered surface m.

When the instrument panel 1 is injection-molded in the same manner as in the prior art using the blow-out mold 3 and the movable mold 6, as shown in FIG. 4 and FIG. The mounting hole 2 is formed by the projection 4a and the projection 4b.
Thus, a recess 7 is formed. In this case, the height of the projection 4a and the plate thickness of the air outlet 1a are the same, the mounting hole 2 is formed as a through hole in the air outlet 1a, and the recess 7 is formed as a closed hole. The mounting hole 2 is not necessarily a through hole, but may be a closed hole as long as the pivot 9 of the register 8 can be rotatably fitted. The thickness of the closed end 1b that closes the recess 7 is determined by the difference in height between the protrusion 4a and the protrusion 4b. Mounting hole 2
A protrusion 1c corresponding to the tapered surface m of the projection 4a is formed at an outer opening edge portion of the projection 4a, and a chamfered portion n corresponding to the inclined bulging portion 4c of the projection 4a is formed at an inner opening edge portion of the mounting hole 2. Is formed.

Injection-molded instrument panel 1
6 is pushed out of the movable die 6 by the protruding operation of the extrusion die 4 of the blow-out die 3 in the same manner as in the prior art, and the pair of upper and lower extrusion dies 4 perform the closing operation, as shown in FIG. In the process shown in (b), the projection 4b comes out of the recess 7, and the projection 4a comes out of the mounting hole 2.

In the state of FIG.
The molding contraction force F of the instrument panel 1 which is generated in the direction of the arrow of FIG.
And are added to the engaging portion of the concave portion 7 in a dispersed manner. In the state of FIG. 7A, the engagement area between the projection 4a and the mounting hole 2 is sufficiently large, and the molding contraction force applied from the mounting hole 2 to the projection 4a is dispersed to such an extent that the mounting hole 2 is not deformed. It is getting smaller.

7A, when the upper and lower extrusion dies 4 are further closed, as shown in FIG. 7B, the projections 4b are first removed from the recesses 7 with the projections 4a remaining in the mounting holes 2. As shown in FIG. Exit. At this time, the molding contraction force F of the instrument panel 1 is not dispersed and is applied to the engagement portion between the projection 4a and the mounting hole 2.
Since the tapered surface m of the projection 4a escapes to the chamfered portion n of the mounting hole 2, it is possible to prevent the molding shrinkage force from directly acting on the edge of the mounting hole 2 to deform it. Finally, the projection 4a is attached to the mounting hole 2.
And the removal of the instrument panel 1 is completed.

As shown in FIG. 8, a register 8 is mounted on the air outlet 1a of the instrument panel 1 formed as described above by inserting its pivot 9 into the mounting hole 2. An overhang 1b is formed at the outer opening of the mounting hole 2, but the pivot 9 is inserted only halfway through the mounting hole 2, so that the overhang 1b does not hinder the pivot 9. Therefore, the pivot 9 is always inserted in the mounting hole 2 in a stable state, and the mounting and operability of the register 8 are improved.

The recess 7 formed in the vicinity of the mounting hole 2 of the air outlet 1a of the instrument panel 1 is formed as a closed hole because of the air conditioning for preventing the air flow in the recess 7. In some cases, the recess 7 may be a through hole. In this case, the protrusions 4a and the protrusions 4b of the extrusion die 4 may be at the same height. When the recess 7 is formed as a through hole, the projection 4a and the projection 4b simultaneously come out of the mounting hole 2 and the recess 7, and as a result, the instrument panel molding contraction force can be obtained without partially chamfering the leading edge of the projection 4a. , The deformation of the mounting hole 2 is prevented.

Further, a pair of projections 4b are formed on both sides of the projection 4a of the extrusion die 4, so that the molding contraction force F of the instrument panel 1 is distributed to a total of three of the projection 4a and the pair of projections 4b. However, the projections 4b may be formed at one location on one side in the molding contraction direction of the projection 4a, or at three or more locations on one or both sides.

The present invention can of course be applied to the air outlet 1a provided only on one of the left and right sides of the instrument panel 1.

According to the present invention, other than the first aspect, the following configuration is also possible.

The height of the protrusion protruding near the protrusion of the extrusion die is lower than the height of the protrusion.
The method for preventing deformation during the molding of the instrument panel as described.

2. The method for preventing deformation of an instrument panel according to claim 1, wherein an edge portion of a tip of the protrusion of the extrusion die in a direction opposite to a contraction direction of the instrument panel is chamfered.

[0028]

According to the present invention, the molding contraction force of the instrument panel when the injection-molded instrument panel is released from the extrusion die is reduced by the mounting of the projection of the extrusion die and the instrument panel air outlet. Forming the projections and the mounting holes to disperse and add to the engaging portion with the hole, the convex portion of the extrusion die and the concave portion of the instrument panel air outlet formed by this convex portion The contraction force is reduced, and the deformation of the mounting hole is avoided, so that an automobile instrument panel having a stable shape and a high product value can be formed.

Also, by making the height of the convex portion lower than the protrusion of the extrusion die, the concave portion near the mounting hole of the instrument panel air outlet has a closed hole structure, and the air conditioning design of the air outlet is improved. An easy instrument panel can be provided.

Further, if the protrusion is made lower than the protrusion of the extrusion die, and the leading edge of the protrusion is partially chamfered, the air outlet is provided before the protrusion comes out of the mounting hole of the air outlet of the instrument panel. The protrusion of the extrusion die comes off from the recess of the part,
Even if the molding contraction force of the instrument panel is applied only to the protrusion, the molding contraction force is absorbed by the chamfered tip edge portion of the protrusion escaping from the mounting hole, so that the deformation of the mounting hole is reliably prevented. .

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of an instrument panel molding die for explaining the method of the present invention.

FIG. 2 is a plan view of an outlet mold in the mold of FIG.

FIG. 3 is an enlarged sectional view taken along the line AA of FIG. 1;

FIG. 4 is a sectional view of an instrument panel and a mold formed by the mold of FIG. 1;

FIG. 5 is an enlarged sectional view taken along line BB of FIG. 4;

FIG. 6 is a cross-sectional view of the instrument panel formed by the mold of FIG. 1 when the mold is removed.

FIGS. 7A and 7B are enlarged cross-sectional views at the time of each operation along the line CC in FIG. 6;

FIG. 8 is a partial cross-sectional view when an external component is attached to an air outlet of an instrument panel formed by the method of the present invention.

FIG. 9 is a perspective view of an instrument panel of an automobile.

FIG. 10 is an enlarged sectional view taken along the line DD in FIG. 9;

FIG. 11 is a sectional view of a mold at the time of instrument panel molding by a conventional manufacturing method.

FIG. 12 is an enlarged sectional view taken along line EE of FIG. 11;

FIG. 13 is a cross-sectional view of the instrument panel formed by the mold of FIG. 11 at the time of demolding.

14 (a), (b), and (c) are enlarged cross-sectional views at the time of each operation along line GG in FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 instrument panel 1 a air outlet 2 mounting hole 3 outlet 4 extrusion 4 a projection 4 b projection 5 extrusion guide 6 movable 7 recess

Claims (1)

(57) [Claims] An inner surface of a resin instrument panel of an undercut structure having an end portion having a cylindrical air outlet portion having both ends open and formed with mounting holes for supporting external components on upper and lower wall surfaces, A pair of upper and lower extrusion dies integrally formed with the projections forming the mounting holes, and the upper and lower extrusion dies are located between the pair of upper and lower extrusion dies and are relatively moved up and down to approach the upper and lower extrusion dies in the vertical direction. After the outer surface of the air outlet portion and its peripheral portion are formed by a movable mold, the instrument panel is moved from the movable mold by the upper and lower extrusion molds of the blow-out type. In the injection molding process of the instrument panel, which extrudes and moves the upper and lower extrusion dies closer to each other to release the projections of the extrusion dies from the mounting holes of the air outlet portion, the molding shrinkage of the injection-molded instrument panel is performed. A protrusion is integrally formed on the surface of the extrusion die adjacent to the protrusion of the extrusion die in the direction, and a recess is formed in the vicinity of the mounting hole of the air outlet portion of the instrument panel with the protrusion, and injection molding is performed. Deformation of the mounting hole by receiving the molding contraction force of the instrument panel when the instrument panel is released from the mold by the extrusion die, at the engaging portion between the projection and the mounting hole, and at the engaging portion between the convex portion and the concave portion. A method for preventing deformation during molding of an instrument panel, characterized in that deformation is prevented.