JP2002067093A - Injection compression molding die for vehicle front fender - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide injection compression molding technique by which moldings of a complicated shape can be molded. SOLUTION: The injection compression molding die 30 comprises a cavity 31 of the same shape as a front fender, a dummy cavity 34 overhanging from a forward arc part, a dummy cavity 35 overhanging from a rear arc part and a film gate 40 formed at a position facing almost the center of a wheel arch part. Consequently, a part of a resin is swelled into the dummy cavities 34 and 35, when the resin is forcibly spread in the compression molding process After the cavity 31 is filled with the resin on account of a damming action by a throttling part, a part of the resin overflows into the dummy cavities 34 and 35. Thus the overflowing of the resin into the dummy cavities 34 and 35 is permitted and the positive filling of the cavity 31 with the resin is ensured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an injection compression molding die suitable for molding a front fender of a vehicle.

[0002]

2. Description of the Related Art An injection press (injection compression) molding method is one of the resin molding methods.
The details are shown in JP-A-179722, "Injection molding method and molding machine". The principle of the injection compression molding method, which is the background of the present invention, will be described with reference to the following drawings.

FIGS. 12A and 12B are diagrams showing the principle of a conventional injection compression molding method. (A) shows an injection step. First, the outline of the apparatus will be described. A fixed plate 102 for mounting a fixed die 101 and a pressure receiving plate 10 for mounting a mold clamping cylinder 103 are described.
4 are provided with a movable plate 106, and a movable plate 106 is attached to these tie bars 105 so as to be movable.
07, and the movable plate 106 is pushed out in the mold clamping direction by the mold clamping cylinder 103 to move the movable mold 1 to the fixed mold 101.
07 can be clamped.

The movable mold 107 is held at a position slightly opened from the mold clamping completion position, and a fixed amount of molten resin 109 is injected from an injection nozzle 108 and filled. This is the injection step in the injection compression molding method.

In FIG. 1B, the cavity 109 is filled with the resin 109 by moving the movable mold 107 forward by the action of the mold clamping cylinder 103 and the movable plate 106.
Obtain molded articles. This is the compression molding step in the injection compression molding method.

[0006] The injection compression molding method described above is a method of filling the cavity while spreading the resin,
It is said that a molded article having a complicated shape can be obtained as compared with a normal injection molding method (injection molding method).

[0007]

However, it has been found that a molded article having an extremely complicated structure, which will be described with reference to the following drawings, has the following problems. FIG. 13 is a front view of the front fender of the vehicle. The resin 112 is injected and filled from the gate 111, and the resin 112 is pushed and expanded as indicated by arrows in the next compression molding step. May not rotate enough. Further, even if it rotates, the filling pressure varies, so that there is a problem that deformation such as sink marks and warpage occurs after molding.

Accordingly, an object of the present invention is to provide an injection compression molding technique capable of molding a molded article having a complicated shape.

[0009]

In order to achieve the above object, a first aspect of the present invention is to fill a cavity with a fixed amount of resin by injection,
Next, a front fender including a front arc portion facing the headlamp and a rear arc portion facing the door is formed by an injection compression molding method in which the movable die is moved in the mold clamping direction to spread the resin to obtain a molded product. In some cases, the mold includes a dummy cavity extending from the cavity beyond the front circular arc portion and the rear circular arc portion, and has a narrowed portion at a boundary between the dummy cavity and the cavity, so that the dummy can be quantitatively measured. It is characterized in that a part of the resin filled in the cavity is expanded into the front and rear dummy cavities by adding the amount of resin filled in the cavity.

At the injection stage, which is a pre-process of compression molding, a large resin is injected and filled into the cavity. In the next compression molding step, the resin is spread, and at this time, a part of the resin is swelled into the dummy cavity. Since a part of the resin overflows to the dummy cavity after the cavity is filled with the resin due to the damping action of the restricting portion, the resin filling into the cavity is ensured by allowing the overflow of the resin to the dummy cavity. . Therefore, according to the first aspect, the front fender of the vehicle, which is a molded article having a complicated shape, can be favorably molded without generating sink marks, warpage, and the like.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The drawings should be viewed in the direction of reference numerals. FIG. 1 is a side view of a vehicle according to the present invention,
This shows that the front fender 20 of the present invention is attached to a portion surrounded by the inner fender 12, the side sill 13, the door 14, the hood 15, the combination lamp 16, and the front bumper 17 surrounding the front wheel 11 of the vehicle 10.

FIG. 2 is an enlarged view of the front fender according to the present invention. The front fender 20 is a resin molded product (correctly, a resin injection compression molded product) having a hook shape or an L shape as a whole. Wheel arch 21 which is a large arc, small straight part 22 facing the side sill, rear arc 23 facing the door, very loose upper arc 24 facing the bonnet, small front arc 25 facing the combination lamp (head lamp). , And a belt-like overhanging portion 26... And a bolt hole 27 are added to the peripheral edge. By passing bolts through these bolt holes 27, other components can be attached to the front fender 20 or the front fender 20 can be attached to the vehicle body side.

FIG. 3 is a sectional view taken along the line 3-3 in FIG. 2, and has a cross-sectional structure in which the rear arc portion 23 facing the door includes an undercut portion (a portion that cannot be removed with a normal mold structure) 28. Indicates that

An injection compression mold for molding the front fender 20 having a complicated shape as described above will be described below. FIG. 4 is a sectional view of an injection compression molding die for a front fender of a vehicle according to the present invention. An injection compression molding die 30 for a vehicle front fender (hereinafter abbreviated as “injection compression molding die 30”) has a cavity. 31 includes an inclined core 33 that includes a convex portion 32 and forms a part of a mold.
A movable mold 36 including dummy cavities 34 and 35 connected to both ends of the cavity 31, and a fixed mold 39 including a concave portion 37 forming the cavity 31 and having a sprue 38.
And consisting of

Although not described in detail, when the resin is solidified in the cavity 31, the inclined core 33 projects when the movable mold 36 is separated from the fixed mold 39, and moves the molded product a predetermined distance from the convex portion 32. (Distance that can avoid undercut). Then, the molded product can be paid out from the movable mold 36. That is, the inclined core 33 is a component for preventing undercut.

FIG. 5 is an enlarged view of a portion 5 of FIG. 4, and shows that the dummy cavity 35 is formed so as to extend from the cavity 31 via the throttle portion 49, which is not described in FIG. The same applies to the other dummy cavity 34 (see FIG. 4). That is, the narrowed portion 49,
49 is provided, and is communicated with the dummy cavities 34 and 35 through the throttle portions 49 and 49.

From the cavity 31 to the dummy cavity 35
When the resin swells, the restricting portion 49 exerts a resistance effect. Therefore, the resin does not travel to the dummy cavity 35 unless the cavity 31 is sufficiently filled. As a result,
It is considered that the filling of the resin in the cavity 31 becomes good, while the filling of the resin in the dummy cavity 35 becomes insufficient, and the dummy cavity 35 remains in a burr shape. However, since the resin that has proceeded to the dummy cavity 35 is cut off later, there is no inconvenience in the burr shape.

FIG. 6 is a view taken in the direction of arrow 6 in FIG. 4, and shows a cavity 31 having the same shape as the front fender described with reference to FIG. 2, a dummy cavity 34 extending from the front circular arc portion, and a dummy cavity extending from the rear circular arc portion. 35 and a film gate 40 provided at a position facing substantially the center of the wheel arch portion.
And are provided in the injection compression molding die 30.

FIG. 7 is a sectional view taken along line 7-7 of FIG. 6, and FIG.
FIG. 9 is a perspective view of a film gate for supplementary explanation of the above, wherein the lower end of a sprue 38 provided in a fixed mold 39 is connected to a film gate 40 which is a thin flat space, and
The cavity 41 is filled with a resin 41 by injection. The film gate 40 may be a film gate connecting a number of gates from the runner to the cavity in a comb-like shape, or a film gate 40 from the lower end of the sprue 38.
Includes a fan gate that spreads out toward the fan. That is,
There is no particular difference in detail as long as the resin can be filled in an expanded state as compared with the pinpoint gate.

The operation of the injection compression mold described above will now be described. FIGS. 9A and 9B are operation diagrams of the injection compression molding die according to the present invention. (A) shows the completion of the injection step, in which a fixed amount of resin is injected through the sprue 38. Then, the resin 41 spreads at the film gate 40 and thereafter reaches the cavity 31, so that the cavity 31 can be filled in a wider area than in the related art as shown in the figure.

It is not preferable to place the film gate 40 at a position near the overhanging portions 26, 26 formed to overhang from the vicinity of the wheel arch portion 21. When the mounting holes (reference numerals 51 and 51 in FIG. 10) for attaching the inner fender 12 (see FIG. 1) to the wheel arch portion 21 are formed, it is also preferable to form the film gate 40 across the mounting holes. Absent. In these cases, because the resin is cracked or split, the flow of the resin is disturbed and appears as a defect in the molded product. Therefore, in this embodiment, the film gate 40 is positioned substantially at the center of the wheel arch portion 21. In addition, since the center of the wheel arch portion 21 is substantially equidistant from the plurality of corners, by providing a gate at such a position, the resin can be spread over the plurality of corners with a substantially uniform filling pressure.

FIG. 2B shows the time when the compression molding is completed, and the resin 41 is pushed out by the mold clamping operation. At this time, the following effects can be expected. Since the resin 41 has already spread sufficiently in FIG. 3A, the resin 41 can be easily turned to the corners of the cavity 31 by expanding the resin 41 as shown in FIG. Since the resin 41 flows out into the dummy cavities 34 and 35, there is no need to worry about the shortage of resin around the front circular arc portion 25 and the rear circular arc portion 23 indicated by broken lines.

FIG. 10 is a view showing a molded product just taken out of the injection compression molding die according to the present invention. This molded product 43 includes a gate 44, a dummy 45 projecting from the front circular arc portion 25, and a rear circular arc portion. A dummy 46 overhanging from 23 remains. Therefore, these gates 44, dummy 45,
46 is excised. Then, mounting holes 51 for mounting the inner fender are opened as necessary.

FIG. 11 is a front view of the vehicle front fender according to the present invention.
4. As a result of cutting off the dummies 45 and 46, the front fender 20 of the vehicle having a good shape could be obtained as shown in FIG. That is, the thickness and density of the corners 47 and 48 and the overhang portions 26.

In the first aspect, it is not always necessary to make the gate a film gate. However, since a synergistic effect between the dummy cavity and the film gate can be expected, it is preferable to employ both the film gate and the dummy cavity.

[0026]

According to the present invention, the following effects are exhibited by the above configuration. According to the first aspect of the present invention, at the injection stage which is a pre-process of the compression molding, a large resin is injected and filled into the cavity. In the next compression molding step, the resin is spread, and at this time, a part of the resin is swelled into the dummy cavity. Since part of the resin overflows to the dummy cavity after the cavity is filled with resin due to the damping action of the narrowing portion, by allowing the resin to overflow to the dummy cavity,
Ensuring that the cavity is filled with resin. Therefore, according to the first aspect, the front fender of the vehicle, which is a molded article having a complicated shape, can be favorably molded without generating sink marks, warpage, and the like.

[Brief description of the drawings]

FIG. 1 is a side view of a vehicle according to the present invention.

FIG. 2 is an enlarged view of a front fender according to the present invention.

FIG. 3 is a sectional view taken along line 3-3 in FIG. 2;

FIG. 4 is a sectional view of an injection compression mold for a front fender of a vehicle according to the present invention.

FIG. 5 is an enlarged view of a part of FIG. 4;

6 is a view taken in the direction of arrow 6 in FIG. 4;

FIG. 7 is a sectional view taken along line 7-7 of FIG. 6;

FIG. 8 is a perspective view of a film gate.

FIG. 9 is an operation view of the injection compression mold according to the present invention.

FIG. 10 is a view showing a molded product just taken out of an injection compression mold according to the present invention.

FIG. 11 is a front view of the front fender of the vehicle according to the present invention.

FIG. 12 is a principle diagram of a conventional injection compression molding method.

FIG. 13 is a front view of a front fender of the vehicle.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Vehicle, 20 ... Front fender, 21 ... Wheel arch part, 23 ... Rear arc part, 25 ... Front arc part, 30 ...
Injection compression mold for vehicle front fender (injection compression mold), 31: cavity, 34, 35: dummy cavity, 36: movable mold, 39: fixed mold, 41: resin, 43
… Molded product, 49… drawn part.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) // B29L 31:30 B29L 31:30 F term (reference) 3D003 AA04 AA10 BB02 CA53 CA56 3D114 AA03 BA03 CA03 4F202 AH18 AM34 AM35 CA09 CA11 CB01 CK18 4F206 AH18 AM34 AM35 JA03 JL02 JM13 JN32 JQ81

Claims (1)

[Claims] 1. A fixed amount of resin is injected and filled into a cavity,
Next, a front fender including a front arc portion facing the headlamp and a rear arc portion facing the door is formed by an injection compression molding method in which the movable die is moved in the mold clamping direction to spread the resin to obtain a molded product. The molding die includes a dummy cavity extending from the cavity beyond the front circular arc portion and the rear circular arc portion, and includes a throttle portion at a boundary between the dummy cavity and the cavity. An injection compression molding die for a front fender of a vehicle, characterized in that a part of a resin filled in a cavity is expanded into front and rear dummy cavities by adding an amount of resin filled in a dummy cavity to a fixed amount.