EXTRUDED STEERING WHEEL RIM

This invention relates to a steering wheel assembly.

Steering wheel assemblies for vehicles typically have a steering wheel rim, armature, and spokes extending to a hub within the center of the rim The rim may be formed from rolled metal or, alternatively, a plastic core formed by a mold. A lining or leather wrap may be added to the rim for driver comfort.

Steering wheel assemblies are relatively expensive. Part of the expense arises from the use of durable materials, such as a metal or a solid plastic core, to form the steering wheel rim. These materials ensure that the steering wheel has enough rigidity to respond well to inputs from a driver. They are also strong enough to survive the wear and tear that may occur during the operation of the vehicle.

A need therefore exists for a durable and inexpensive steering wheel assembly.

The present invention comprises a steering wheel assembly. The steering wheel assembly has a steering wheel rim that extends around a perimeter. The steering wheel rim may be hollow. To strengthen the rim, reinforcing supports extend at least partially around the perimeter on the steering wheel rim. The steering wheel has an interior surface and an exterior surface. These reinforcing supports may protrude from the interior surface, the exterior surface or both surfaces of the rim.

The inventive steering wheel assembly is made via an extrusion process. Material is extruded through a die. The material is then formed into the shape of a steering wheel rim. Reinforcing supports may be added to the material and may be formed with the rim from the same die. The die may form these supports on an interior surface or an exterior surface of the rim. The steering wheel armature, spoke and hub may be subsequently molded to the extruded steering wheel rim.

By forming the steering wheel rim in this manner, less material is required to construct each steering wheel rim. In addition, the steering wheel

rim has sufficient strength from the reinforcing supports extending along the rim to perform well and to be long lasting. Consequently, a steering wheel may be constructed at very low cost while retaining the strength and durability required for normal vehicle operation.

Figure 1 is a cross-sectional perspective view of a steering wheel assembly, showing steering wheel rim and reinforcing supports.

Figure 2 is a cross-sectional view of the steering wheel rim of Figure 1 formed by a die.

Figure 3 illustrates an alternative cross-section of a steering wheel rim.

Figure 4 illustrates another alternative cross-section of a steering wheel rim.

Figure 5 illustrates another alternative cross-section of a steering wheel rim, including filler material extending around the rim.

Figure 6 illustrates an extrusion process for forming the steering wheel rim of Figures 1-5

Figure 7 illustrates the separation of the steering wheel rim from the extruded material of Figure 6.

Figure 8 illustrates a completed steering wheel rim.

Figure 9 shows the completed steering wheel rim of Figure 8 in a mold.

Figure 1 illustrates a cross-sectional perspective view of an inventive steering wheel assembly 10. The steering wheel assembly 10 has a steering wheel rim 14 extending around a perimeter 18. The steering wheel rim 14 has an inner circumference 16 and an outer circumference 20. Like conventional steering wheel assemblies, the steering wheel assembly 10 also has a steering wheel armature 82, which is attaches the steering wheel rim 14 to spokes 86. The spokes 86 are attached to a hub 90.

The steering wheel rim 14 is an extrusion formed from a die as shown in Figure 2. The die 38 has opening 43 shaped like a cross-section 42 of the steering wheel rim 14. The cross-section 42 is a cross-section of the steering wheel rim 14 in a direction perpendicular to periphery 18 as shown in Figure 1. Here, the cross-section 42 is a continuous, unbroken ring.

The steering wheel rim 14 has reinforcing supports 22, which are formed on an interior surface 26 and an exterior surface 30 of the steering wheel rim 14. These reinforcing supports 22 are extrusions and are also formed by the die 38 as shown in Figure 2. In addition, the die 38 forms the interior volume 50 of the steering wheel rim 14. Consequently, less material may be used to form the steering wheel rim 14 than in other conventional methods. Reinforcing supports 22 strengthen the steering wheel rim 14.

Figure 3 shows an alternative cross-section 44 for the steering wheel rim 14. The difference between the cross-section 42 of Figure 2 and the cross-section 44 of Figure 3 is the absence of reinforcing supports 22 on the exterior surface 30 of the steering wheel rim 14. Instead, reinforcing supports 22 are only provided on the interior surface 26. Furthermore, the first reinforcing support 62 extends from a first location 54 to a second location 58 of the interior surface 26 across the interior volume 50. Similarly, a second reinforcing support 66 is attached at a third location 56 and a fourth location 60 of the interior surface 26. Both reinforcing supports 62, 66 meet at an intersection 67.

Figure 4 illustrates cross-section 46. Here, in contrast to the cross- section 44 of Figure 3, the reinforcing supports 22 do not extend entirely across the interior volume 50. Instead, the steering wheel rim 14 is provided with reinforcing supports 22 that protrude above the interior surface 26 but do not intersect.

Figure 5 illustrates another alternative cross-section, cross-section 48, here having both reinforcing supports 64 on the interior surface 26 and reinforcing supports 68 on the exterior surface 30 of the steering wheel rim 14. In addition, a filler material 34 is molded onto the exterior surface 30 of the steering wheel rim 14. As shown, the reinforcing supports 68 not only strengthen the steering wheel rim 14 but prevent rotation of the filler material 34 along an arc R. Accordingly, the reinforcing supports 68 prevent the filler material 34 from being twisted on a steel wheel rim 14 by a vehicle driver.

The cross sections 42, 44, 46 and 48 are all formed by a die, such as the die 38, having a shape to form by extrusion the foregoing cross-sections. The steering wheel rim 14 may be made from any suitable material 94, such as plastic, magnesium, aluminum or other extrudable material. A plastic, such as LEXAN EXL™ resin made by the GENERAL ELECTRIC COMPANY™, may be used.

The technique for extruding a steering wheel rim 14 will now be explained with reference to Figures 6-8. As shown in Figure 6, a die 38 is provided with a source of a material 94 in an extrudable state. At pressure, the material 94 is passed through die 38 and formed around form 40, a cylinder having a circumference C, which is about the circumference of the inner circumference 16 of the steering wheel rim 14 as shown in Figure 1. Following the extrusion of the material 94 through the die 38, as shown in Figure 7, a segment 98, here a loop having inner circumference C, is cut from the extruded material 100. Hence, a tube 70 having first end 74 and a second end 78 is formed.

As shown in Figure 8, a first end 74 and a second end 78 of a tube 70 are joined, such as by mating plugs or other connectors. In this way multiple steering wheel rims 14 may be formed quickly and with very little expense from the extruded material 100. As shown in Figure 9, the tube 70 may then be placed in a mold 104. The mold 104 is provided with a form 108 in which a steering wheel armature 82, spokes 86 and a hub 90 may be molded to the tube 70.