JPH0460866B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a resin core material for an automobile steering wheel.

<Prior art and its problems> As illustrated in FIGS. 1 and 2, a conventional steering wheel core material includes a boss core metal a that is fitted onto a steering shaft (not shown), an outer rim core metal b, and spokes that connect the two. Consisting of a core metal c,
Metal round bars or pipes have been used for the rim core metal b and spoke core metal c.

However, in the case of such a conventional steering wheel core material, the curved center part c' of the spoke core metal, the boss core metal a, and both ends of the spoke core metal
There was a problem in that c'', c'' and the rim core metal b had to be welded d, l, and quality control of the welding strength also required a large number of man-hours. Another disadvantage was that it was heavy.

<Object of the Invention> The present invention was made in view of the above-mentioned circumstances, and is a lightweight, low-cost, easy-to-form product made of synthetic resin that is blow-molded without sacrificing the strength required as a reinforcing body for automobile steering wheels. Its purpose is to provide core materials for steering wheels.

<Structure of the Invention> The present invention is a resin core material for a steering wheel, which comprises a mounting surface for attaching a boss portion fitted to a steering shaft, an annular rim core material, and a spoke core material for connecting the two. It is integrally constructed from the same parison, and is characterized in that opposing wall surfaces of the parison are crimped to each other at appropriate locations of the rim core material, spoke core material, and the entire surface of the boss mounting surface. .

<Embodiment of the Invention> An embodiment of the present invention will be described below with reference to the accompanying drawings. In FIG. 3, the steering wheel resin core material 1 is integrally molded in a blow molding mold (not shown), and the rim core material 2 has molds such as those shown in cross section in FIG. 4 at appropriate locations. Eight parison opposing wall crimping portions 2' are provided at equal intervals in the circumferential direction. Furthermore, parison opposing wall crimping parts 3' and 3'', the cross sections of which are shown in FIGS. 5 and 6, are provided at appropriate locations on the spoke core material 3, and
The opposing walls of the parison are crimped to each other on the entire surface. All the parts other than the above-mentioned crimping part are formed hollow, and the whole part is in communication. Note that 5 is a mounting hole for mounting the boss portion. When molding the resin core material, a width slightly larger than the outer diameter of the rim core material is formed between two mold halves in which cavities corresponding to the boss mounting surface, the spoke core material, and the rim core material are carved. A flat cylindrical polyamide molten parison is introduced and the mold is closed, and the parison is cut off at the outer periphery of the cavity of the rim, spoke, and boss attachment parts, and air is blown into the parison to perform blow molding.

At this time, at the crimping points indicated by diagonal lines in Figure 3, the distance between the opposing mold cavity surfaces is set to be less than twice the parison wall thickness when the mold is closed, and the distance between the mold cavity surfaces is set so that it is less than twice the parison wall thickness when the mold is closed. For example, the parison is sandwiched and crimped from the left and right sides to form a crimped portion, and the strength and rigidity required for the resin core material can be guaranteed. The burr portions of the parison remaining on the outer periphery of the spoke portions and boss portions and the inner and outer peripheries of the rim portion are removed after the mold is released and reused.

As the synthetic resin forming the above-mentioned core material, polypropylene, polyethylene, ABS, polyethylene terephthalate, polybutylene terephthalate, nylon, polyacetal, etc. are used alone or in combination with glass fiber, carbon fiber, etc. as a reinforcing agent.

<Effects of the Invention> As detailed above, according to the present invention, the rim core material, spoke core material, and boss mounting surface of the steering wheel core material are integrally formed by blow molding a resin material. It is significantly lighter than conventional metal core materials, does not require any welding, and therefore does not require quality control of welding strength, resulting in a significant reduction in man-hours and lower costs. effective.

[Brief explanation of the drawing]

Figure 1 is a bottom view of a conventional steering wheel core, Figure 2 is an enlarged sectional view taken along the - line in Figure 1, and Figure 3 is a bottom view of a conventional steering wheel core.
The figure is a simplified plan view of the core material according to the present invention, FIG. 4 is an enlarged cross-sectional view taken along the line - in FIG. 3, FIG. 5 is an enlarged cross-sectional view taken along the line - in FIG. 3, and FIG. Enlarged cross-sectional view. 1... Steering wheel core material, 2... Rim core material, 3... Spoke core material, 4... Boss mounting surface.

Claims (1)

[Claims] 1 A resin core material for a steering wheel, in which a mounting surface for attaching a boss portion fitted to a steering shaft, an annular rim core material, and a spoke core material for connecting the two are integrally constructed from the same parison. A resin core material for a steering wheel, characterized in that opposing wall surfaces of the parison are pressed together at appropriate locations of the rim core material, spoke core material, and the entire surface of the boss mounting surface. .