GB2061848A

GB2061848A - Steering wheel

Info

Publication number: GB2061848A
Application number: GB8033548A
Authority: GB
Original assignee: Nissan Motor Co Ltd
Current assignee: Nissan Motor Co Ltd
Priority date: 1979-10-17
Filing date: 1980-10-17
Publication date: 1981-05-20
Also published as: DE3038948A1; JPS5657576A; FR2468156A1

Abstract

An improved steering wheel structure has substantially lighter weight. The steering wheel (10) comprises a synthetic resin core (20) and an outer member (22) covering the core. The core is made of a synthetic resin having sufficient elastic modulus for providing sufficient stress against a bending force applied upon steering. <IMAGE>

Description

SPECIFICATION Steering wheel The present invention relates to a steering wheel for an automotive vehicle, aircraft or the like, and more particularly to an improved steering wheel structure of substantially light weight.

As known to those skilled in the art, a steering wheel requires substantially high rigidity for resisting the bending moment applied thereto upon steering operation. For meeting this requirement, the conventional steering wheel comprises a rigid core made of a steel material such as stainless steel bars and/or plates and a soft, flexible outer member covering the core. In general, the outer member is made of a synthetic resin such as polypropylene, vinylchloride resin, urethane, or the like for comfort in gripping.

Such conventional steering wheels are heavy due to the relatively heavy weight of the steel core, and also possibly cause vibration during high speed driving. For preventing steering wheel vibration, various improvements have been proposed. Namely, the support position of the steering column is determined as close as possible to the steering wheel and the weight of the parts other than the core has been reduced as much as possible. However, such conventional improvements have not satisfied or succeeded in effectively preventing the steering column from vibrating.

Therefore, it is an object of the present invention to provide an improved steering wheel of substantially light weight.

Another and more specific object of the present invention is to provide an improved steering wheel having a core made of synthetic resin.

For accomplishing the above-mentioned and other objects sought in the present invention, there is provided an improved steering wheel for an automotive vehicle and the like, which comprises a core made of substantially rigid synthetic resin and an outer member made of a soft, flexible resin covering the core.

According to the preferred embodiment of the present invention, the synthetic resin comprising the core has sufficient elastic modulus against bending, i.e. an elastic modulus greater than 30,000 kg/cm2.

In the accompanying drawings: Figure 1 is a fragmentary perspective view of the preferred embodiment of a steering wheel according to the present invention; Figure 2 is a partial plan view of the steering wheel of Fig. 1, in which a horn pad and an outer member are cut away for showing the core therein; Figure 3 is a sectional view of the steering wheel of Fig. 1 taken along the line Ill-Ill of Fig. 2; and Figure 4 is an enlarged sectional view of the steering wheel of Fig. 1 taken along the line IV-IV of Fig. 3.

Referring now to the drawings, there is illustrated a preferred embodiment of a steering wheel for an automotive vehicle, etc., according to the present invention. The steering wheel is generally represented by the reference numeral 10 and comprises a substantially annular circular grip portion 1 2 and a spoke portion 14. The spoke portion 14 has a central portion 1 6 to be connected with a steering shaft (not shown) extending through a steering column (not shown). The spoke portion 14 is provided with a horn pad 18 slightly spaced therefrom.

The grip portion 1 2 comprises a substantially annular circular core 20 and an outer member 22 entirely covering the core. Likewise, the spoke portion 14 comprises a core 24 and an outer member 26 entirely covering the core. As shown in Figs. 2 to 4, the core 24 of the grip portion 1 2 is of a circular configuration, and the core 20 of the spoke portion 14 is formed into a C-shaped configration having some additional ribs 21. The ribs 21 formed on the C-shaped core 20 are substantially parallel to the end sections of the C-shape. By forming the core 20 into the above-mentioned shape, rigidity of the spoke portion is increased and the sectional area and stress against the bending moment applied upon operating the steering wheel is therefore increased.

Although, in the embodiment shown, the two ribs 21 are formed between the end sections of the C-shaped core 20, the number of ribs and shape thereof are not be limited to the embodiment shown, and it can be modified in various ways without departing from the concept of providing a larger resistance to the rotational bending moment applied thereto. Furthermore, although a circular core 24 is shown in the preferred embodiment as the core of the grip portion, the shape of the core will be more beneficially embodied to correspond to the shape of the outer member so that the grip portion may be easily formed.

The core 24 has a cylindrical central portion 28 with teeth or splines 30 formed on the inner periphery thereof. The teeth or splines 30 engage with teeth or splines 32 formed on the outer periphery of a metalic insert 34. The insert 34 is formed with teeth 36 for engaging teeth 38 formed on the outer periphery of a steering shaft 40. The engagement between the teeth 30, 32 and 36, 38 transmits the rotational force applied to the steering wheel to the steering shaft 40 upon steering operation.

Additionally, it should be noted that the overall shape of each element comprising the steering wheel is not so important for the present invention. Therefore, the disclosure given herein should be considered as merely typical and generic to the construction of the steering wheel.

Both of the cores 20 and 24 are made of the same synthetic resin and preferably are formed integrally. By so doing, the steering wheel core can be simply formed in a mold, thereby obviating the steps of shape forming steel bars and welding the spoke and grip portion cores to produce the steering wheel core, thus greatly simplifying the construction process and lowering the cost thereof. Additionally, by forming the entire steering wheel core in mold, various shapes of spoke and grip portion cross sections may be obtained for further strengthening the core while maintaining the weight at a minimum.

The synthetic resin comprising the core 20 and 24 has a sufficient elastic modulus, i.e.

more than 30,000 kg/cm2, against bending For this, the synthetic resin for the core is chosen from polyvinyl acetal of polyvinyl terephthalate, polybutylene, nylon resin or nylon resin with glass fiber. For example, the nylon resin with glass fiber for the core is available from Du Pont de Nemours, E. I. and Co.

under the trade name "Zitel". As in conventional steering wheels, the outer members 22 and 26 are made of polypropylene, vinyl chloride resin, urethane, or the like.

The steering wheel thus constructed is strong enough to resist bending moments applied thereto upon steering operation with respect to bending stress against parallel bending moment. A bending test of applying a 100 kg weight on both sides of the grip portion was performed. The result was that the amount of wheel deflection was less than 20 mm and the amount of plastic deflection after releasing the weight was less than 3 mm. With respect to bending stress against a load applied to one side of the wheel, a bending test of applying a 40 kg weight at one side thereof was performed. The result was that the amount of deflection was less than 45 mm and the amount of plastic deflection after releasing the weight was less than 7 mm. This satisfies the requirement of the bending stress for the steering wheel.

Therefore, according to the present invention, there is provided an improved steering wheel of substantially light weight but having sufficient bending stress. The steering wheel of the present invention can be effectively prevented from vibration even when the vehicle is driven at substantially high speeds.

Claims

1. A steering wheel comprising: a core made of a synthetic resin having sufficient elastic modulus for providing enough bending stress for the steering wheel; and an outer member surrounding said core and made of a substantially soft and flexible synthetic resin.

2. A steering wheel as set forth in claim 1, wherein said core is made of a synthetic resin having an elastic modulus greater than 30,000 kg/cm2.

3. A steering wheel as set forth in claim 1, wherein said steering wheel has bending stress resistance so that the deflection amount thereof is less than 20 mm and the plastic deflection amount is less than 3 mm when 100 kg of weight is applied to both sides of the wheel, and so that the deflection amount thereof is less than 45 mm and the plastic deflection amount is less than 7 mm when 45 kg of weight is applied to one side of the wheel.

4. A steering wheel comprising: a core made of synthetic resin having sufficient elastic modulus and including a substantially annular ring-shaped grip portion and substantially plane spoke portions of generally C-shaped configration in cross-section for providing sufficient bending stress for the steering wheel; and an outer member surrounding said core and made of substantially soft and flexible synthetic resin.

5. A steering wheel s set forth in claim 4, wherein said core is made of a synthetic resin having an elastic modulus greater than 30,000 kg/cm2.

6. A steering wheel as set forth in claim 4 or 5, wherein said cross-sectional C-shaped core spoke portion includes additional ribs in substantially parallel relation to the end sections of said C-shape for reinforcement against bending force applied in the laterai direction with respect to the upper plane of the spoke portions.

7. A steering wheel as set forth in claim 4 or 5, wherein said steering wheel has bending stress resistance so that the deflection amount thereof is less than 20 mm and the plastic deflection amount is less than 3 mm when 100 kg of weight is applied to both sides of the wheel, and so that the deflection amount thereof is less than 45 mm and the plastic deflection amount is less than 7 mm when 45 kg of weight is applied to one side of the wheel.

8. A steering wheel as set forth in claim 5, wherein said core is made of polyvinyl acetal of polyvinyl terephthalate.

9. A steering wheel as set forth in claim 5, wherein said core is made of polybutylene.

10. A steering wheel as set forth in claim 5, wherein said core is made of nylon resin.

11. A steering wheel as set forth in claim 5, wherein said core is made of nylon resin with reinforcement glass fiber.

1 2. A steering wheel comprising: a grip portion of substantially annular circu lar shaped configuration including a first core of a synthetic resin having sufficient elastic modulus and an outer member entirely covering said first core, said first core extending through the entire length of said grip portion; a central portion for engaging a steering shaft and transmitting a steering force to said steering shaft, including a second core made of a synthetic resin having sufficient elastic modulus and formed into a vertically extending cylindrical shaped configuration and a metallic insert splined with both the steering shaft and the cylindrical second cqre for ensuring transmission of the steering force; and spoke portions interposed between said grip portion and said central portion, which spoke portions include a third core of generally Cshaped configration having two end sections in substantially parallel relation to each other and a substantially plane intermediate portion substantially longer than said end sections and made of a synthetic resin of sufficient elastic modulus for providing said third core with sufficient stress against rotational bending.

1 3. A steering wheel as set forth in claim 12, wherein said first, second and third cores are made of the same resin and are formed integrally in a mold.

14. A steering wheel as set forth in claim 12 or 13, wherein said first, second and third cores are made of a synthetic resin having elastic modulus greater than 30,000 kg/cm2.

1 5. A steering wheel as set forth in claim 13, wherein said cross-sectional C-shaped core spoke portion includes additional ribs in substantially parallel relation to the end sections of said C-shape for reinforcement against bending force applied in the lateral direction with respect to the upper plane of the spoke portions.

1 6. A steering wheel as set forth in claim 13, wherein said steering wheel has bending stress resistance so that the deflection amount thereof is less than 20 mm and the plastic deflection amount is less than 3 mm when 100 kg of weight is applied to both sides of the wheel, and so that the deflection amount thereof is less than 45 mm and the plastic deflection amount is less than 7 mm when 45 kg of weight is applied to one side of the wheel.

1 7. A steering wheel as set forth in claim 13, wherein said resin to be formed into said cores is chosen among polyvinyl acetal of polyvinyl terephthalate, polybutylene, nylon resin and nylon resin with glass fiber.

1 8. A steering wheel substantially as described with reference to, and as illustrated in, the accompanying drawings.