JPH0116698Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a core metal of a steering wheel used in an automobile steering device.

[Prior Art] The core of a steering wheel generally consists of an annular rim, spokes that are fixed to the rim, and a boss that fixes the steering shaft.These spokes and rim transmit rotational force to the steering shaft. A certain level of strength is required in order to absorb energy during collisions and the like. However, in conventional rims, the thickness of the core metal is the same around the entire circumference of the rim, based on the area where the most strength is needed, or reinforcement is applied locally. However, considering the stress distribution acting on the rim, such a conventional shape of the core metal cannot necessarily be said to be rational.

[Problem that the invention aims to solve] For example, there are so-called one-spoke types in which one spoke is attached to the rim, and two-spoke types in which two spokes are attached in a roughly V-shape. If the spokes are fixed to one side within half the circumference of the rim, a large stress will be generated on the side of the rim where the spokes are fixed.
In the area where the spokes are not fixed, the stress gradually decreases, so the strength can be small. Therefore, if the strength is uniform all around the rim, the strength of the part on the side where the spokes are not fixed will be higher than necessary, and the material of the core metal will be wasted by this unnecessary strength. This increases the weight accordingly.

Accordingly, an object of the present invention is to provide a core metal for a steering wheel that eliminates waste in terms of weight and strength of the rim and makes it possible to reduce the weight of the rim.

[Means for solving the problem] In order to achieve the above purpose, the core metal devised by the present inventor is such that the spokes are fixed to the rim at appropriate locations within half the circumference of the rim. In the core metal of the steering wheel, the rim is composed of a first member on the side to which the spokes are fixed and a second member on the side to which the spokes are not fixed, and the external dimensions of the cross section of the first member and the second member are as follows: are substantially equal to each other, and the first member on the side to which the spokes are fixed has a thicker wall thickness, and the second member on the side to which the spokes are not fixed has a thinner wall thickness.

[Function] The rim of the cored metal with the above structure can have a large moment of inertia at the connection part with the spokes where high strength is required, and a pipe with a thin wall thickness can be used in the parts where the stress is relatively small. By doing so, weight reduction can be achieved. Since the outer diameters of the first member and the second member are the same, even if the second member has a small wall thickness, the amount of synthetic resin exterior material applied to the outside will not increase. .

By reducing the weight of the rim, the rotational moment of the entire steering wheel can be reduced, contributing to improved operability.

[Example] An example of the present invention will be described below with reference to FIGS. 1 and 2. In FIG. 1, reference numeral 1 denotes an annular rim, and two spokes 2, 2 are attached to this rim 1 by, for example, welding in a V-shape. Further, boss portions 3 are attached to the ends of the spokes 2, 2. A serrated hole 4 is formed in the center of the boss portion 3, and an end portion of a steering shaft (not shown) is fixed to this hole 4.

The rim 1 includes a first member 1a located on the side to which the spokes 2, 2 are fixed, and a first member 1a located on the side to which the spokes 2, 2 are fixed;
2 with the second member 1b located on the side where is not fixed.
Consists of parts. These members 1a and 1b have a substantially semicircular shape, and their respective ends are welded together in a fitted state as shown in FIG. 2 to form an annular rim 1. There is. 5 and 5 indicate mutual connection parts.

The first member 1a and the second member 1b are each made of a metal pipe, and the external dimensions (outside diameter in the case of a round pipe) are the same for both members 1a and 1b, but the wall thickness is the same on the side where the spokes are fixed. first member 1 of
A is thicker, and the second one on the side where the spoke is not fixed
Two types of pipes with different wall thicknesses are used so that the member 1b is thin. Further, the outer circumferential surface of each member 1a, 1b is covered with an exterior material (not shown) made of synthetic resin such as polyurethane foam or polypropylene.

According to the rim 1 having the above configuration, it is possible to increase the moment of inertia of the connecting portion with the spokes where high strength is required, and by using a thin-walled pipe in the portion where the stress is relatively small. Therefore, weight reduction can be achieved. and both parts 1
Since the outer diameters of a and 1b are made the same, even if the thickness of the second member 1b is small, the amount of synthetic resin sheathing material applied to the outside of the second member 1b will not increase. In other words, if the outer diameter of a part of the rim was simply made thinner, the amount of synthetic resin used in that part would increase, leading to higher costs, but this example eliminates this and allows the use of synthetic resin. It is economical and cost-effective.

By reducing the weight of the rim, the rotational moment of the entire steering wheel can be reduced, contributing to improved operability.

In the above embodiment, the two members 1a and 1b are divided so that the wall thickness changes approximately at the center in the circumferential direction of the rim 1, but the position of division depends on the diameter of the rim 1, the required strength of the spoke attachment part, and the core metal. They differ depending on the cross-sectional shape, etc., and can be implemented with various modifications without departing from the gist of the present invention. Further, the cross-sectional shape of each member 1a, 1b constituting the rim is not limited to a circular shape, and may be, for example, an ellipse, an oval, or any other irregular cross-sectional shape. It may be in the shape of a core metal.

In addition, in the present invention, the rim may be divided into three or more parts,
In short, it is sufficient to make the cross-sectional external dimensions of each member substantially the same, and to increase the wall thickness of the member on the side to which the spokes are fixed, and to reduce the wall thickness of the member on the side to which the spokes are not fixed.

Furthermore, the present invention can of course be applied to a one-spoke type steering wheel.

[Effects of the invention] According to the invention, it is possible to achieve a rational distribution of material usage by reducing waste in terms of strength and weight of the core metal, making it possible to reduce the weight. Moreover, because the cross-sectional external dimensions of the part to which the spokes are fixed and the part to which the spokes are not fixed are almost the same, the amount of synthetic resin exterior material used to cover the outside of the rim can be reduced. be.

[Brief explanation of the drawing]

FIG. 1 is a front view of a metal core showing an embodiment of the present invention, and FIG. 2 is a sectional view taken along the - line in FIG. 1. 1...Rim, 1a...Member on the side to which the spokes are fixed, 1b...Member on the side to which the spokes are not fixed, 2...Spokes, 3...Boss portion.

Claims (1)

[Scope of utility model registration request] In a core metal of a steering wheel comprising an annular rim and spokes connecting the rim to a boss part, the spokes being fixed to the rim at appropriate locations within half of the entire circumference of the rim. , the rim is constituted by a first member on the side to which the spokes are fixed and a second member on the side to which the spokes are not fixed, and the external dimensions of the cross sections of the first member and the second member are made approximately equal to each other; A steering wheel core metal, characterized in that the first member on the side to which the spokes are fixed has a thicker wall thickness, and the second member on the side to which the spokes are not fixed has a thinner wall thickness.