JPS59171761A - Molding method for car front fender and mold thereof - Google Patents

Abstract

PURPOSE:To prevent production of a weld mark and to prevent partial lowering of an impact strength, by a method wherein a plurality of molten resin flows are created radially from an arch-shaped part forming part. CONSTITUTION:A mold 4 has a cavity 5 corresponding to the shape of a front fender F, and an arch-shaped part forming part 5a of the cavity 5 has a plurality of gates 6 which are open along an arch surface at given intervals. A reinforcing rib forming groove part 7 having a given width is formed in the cavity 5 and in a portion which has a longest distance in a radial direction between the arch-shaped part forming part 5a and the end wall of the cavity. The gates 6 are aligned, and this causes a plurality of molten resin flows R to be created in the cavity 5 radially from those gates 6, resulting in preventing production of a weld mark.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for molding a front fender for an automobile by injection molding a front fender for an automobile having an arched portion along the upper surface of a front wheel from a thermoplastic synthetic resin, and a molding method used in the method. Regarding molds.

Conventionally, front fenders of this type have been molded using polycarbonate resin or blends thereof, taking into consideration damping and connection properties, but this resin has high viscosity, so depending on the gate design of the mold and the There is a problem in that the molten resin flows cross each other and a weld mark is generated at the intersection, reducing the impact strength of that part.

In view of the above, an object of the present invention is to provide a molding method and a mold that can obtain a front fender having excellent overall impact strength.

An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, it is fixed to the vehicle body assembly B so as to form a part of the vehicle body and covers the upper surface of the front wheel Wf.

The front fender F is injection molded using a thermoplastic synthetic resin with relatively good impact resistance, such as polycarbonate resin, polycarbonate alloy resin, polycarbonate ABS resin, etc., and it is attached to the front wheel as shown in Figure 2. an arched portion 1 along the upper surface of Wf;
It consists of a rear end portion 2 of the front pillar/)f1r111 and a fender main portion 3 connected to both sections 1 and 2.

If molded 'M4,' the front fender l as shown in Figure 4.
It has a cavity 5 corresponding to the shape of I'', and a plurality of gates 6 are opened at predetermined intervals along the arch surface in the arch-shaped portion forming part 5a of the cavity 5. As shown in FIG. 3, the gate 6 has, for example, a width ur=
i, Q ~20m, thickness t=3~5mm.

Further, the cavity 5 has a predetermined portion in which the distance in the radial direction from the arched portion forming portion 5a to the gap end wall is the longest, and in the illustrated example, the arched portion forming portion 5a reaches the upper end of the rear end portion forming portion 5b. Groove 7 for forming width reinforcement ribs
8 is a launch that connects each gate 6 to the sprue 9.

By arranging the cages 6 as described above, a plurality of molten resin flows R are formed radially from the gates 6 in the cavity 5 during molding, so that adjacent molten resin flows R are easy to fuse with each other. (As a result, it is possible to prevent the occurrence of weld marks and eliminate problems such as a decrease in partial impact strength.Also, the relationship between the arched portion 1 and the upper end of the rear end portion 2 that is farthest from it in the radial direction can be avoided. Since the reinforcing ribs 10 are formed in between, the weak parts are reinforced by the ribs 10, and together with the effect of preventing the occurrence of weld marks, it is possible to obtain a front fender body which has excellent impact strength over the whole.

As described above, according to the first invention, when injection molding a front fender for an automobile having an arch-shaped portion along the upper surface of a front wheel from thermoplastic synthetic resin, the arch of the front fender is placed in the cavity of a mold. Since multiple molten resin flows are formed radially from the shaped part forming part,
Adjacent molten resin flows easily fuse with each other, thereby preventing the occurrence of weld marks and eliminating problems such as a decrease in partial impact strength.

Further, according to the second invention, in a mold for injection molding a front fender for an automobile having an arch-shaped part along the upper surface of a front wheel from a thermoplastic synthetic resin, the arch-shaped part forming part of the cavity is provided with a mold for injection molding. A plurality of gates are opened at predetermined intervals over the arch surface of the cavity, and a reinforcing rib forming groove is formed in the gap where the distance in the radial direction is the longest from the arch-shaped part forming part to the cavity end wall. This makes it possible to form a reinforcing rib between the arched part and the part furthest from it, to reinforce the vulnerable part, and to obtain a front fender that has excellent impact strength throughout. No way.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which Fig. 1 is a perspective view of an automobile, Fig. 2 is a side view of a front fender, Fig. 3 is an enlarged perspective view of a front fender, and Fig. 4 is a mold. The plan view of FIG. 5 is a sectional view taken along line V--I of FIG. F...front fender, R...molten resin flow, /J
7 J... Front wheel, 1... Arch-shaped part, 4... Molding mold, 5... Cavity, 5σ... Arch-shaped part forming part, 6... Gate, 7... Reinforcement rib formation Yozobe Patent Applicant: Honda Motor Co., Ltd.: Agent: Patent Attorney Ken Ochiai) −

Claims (2)

[Claims] (1) The front fender for automobiles, which has an arched part that covers the top surface of the front wheel, is made of thermoplastic synthetic material.
[A method for molding a front fender for an automobile, which is characterized by forming a plurality of molten resin flows radially from an arch-shaped portion forming part in a JJK-shaped cavity during injection molding from resin. (2) Place it in a mold for injection molding an automobile front fender with an arched part (along the top surface of the front wheel) from thermoplastic synthetic resin. A plurality of gates are opened at predetermined intervals along the arch surface of the cavity, and a groove for forming a reinforcing rib is formed in the cavity at a portion having the longest distance in the radial direction from the arch-shaped portion forming portion to the cavity end wall. A mold for a front fender for an automobile, characterized by being provided with a.