A modular wheel comprises a steering wheel assembly molded such that the airbag cover and steering wheel surface are molded as one, an airbag module loaded into this molded assembly from the rear or bottom, a hub plate with attachment points to the molded assembly and the steering shaft, and attachment hardware, generally embedded in the hub plate. Prior to the introduction of modular steering wheels, also known as wheel airbags, steering wheel assemblies could be attached to the steering shaft in a straightforward manner. Installation of the steering wheel assembly onto the steering shaft was made while viewing the shaft through the hub of the steering wheel from the front face (driver's side) and guiding the steering wheel into place. A nut or bolt was then affixed to the top of the shaft, using the available access through the front face of the steering wheel, and was tightened to pull the steering wheel assembly into its proper functional position. At this point the driver's airbag module was loaded into the open face of the wheel, covering the hub area, and was held in place using fasteners driven through the wheel armature from the back side of the steering wheel assembly.

In contrast, for a modular steering wheel the wheel and airbag module are installed as one unit and there is no longer access to the steering shaft through the face of the steering wheel assembly. This

makes it somewhat more difficult to mate up the hub of the steering wheel with the steering shaft.

During steering wheel assembly various electrical connections must be made between the steering wheel and the vehicle electrical system to power the horn, airbag inflator, and, frequently, additional accessories. These connections are generally made by plugging one or more pigtail connectors located on the steering column into complimentary mating pigtail connectors on the steering wheel assembly. There is always the danger that one or more of these pigtail leads may be damaged during installation and this danger may be exacerbated during blind assembly.

The present invention facilitates attachment of the steering wheel assembly to the steering column.

All required electrical connections between the steering wheel assembly and the vehicle electrical system are made automatically while the steering wheel assembly is being installed onto the shaft; no separate operation or manipulation is required to make the electrical connections. The electrical connection between the steering wheel assembly and the vehicle electrical system takes place only after the steering wheel assembly is sufficiently aligned such that damages to the connector interface cannot occur.

Electrical connection will be achieved regardless of any manufacturing variance occurring in the steering wheel assembly or the steering column assembly.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is an exploded perspective view of the vehicle steering assembly of the present invention.

Figure 2 is an exploded different perspective view of the vehicle steering assembly of Figure 1.

Figure 3 is a perspective view of the assembled steering wheel assembly and the assembled steering column assemblies of Figures 1 and 2.

Figure 4 is a sectional view of the steering wheel assembly of Figure 3 installed onto the steering column assembly of Figure 3.

DETAILED DESCRIPTION OF THE INVENTION A vehicle steering assembly 20 having an improved steering wheel assembly 22 and an improved steering column assembly 24 facilitates the installation of the steering wheel assembly 22 onto the steering column assembly 24. As shown in Figure 1, the steering wheel assembly 22 comprises a steering wheel armature 28, airbag assembly 30 and hub plate 32, which may take the form taught in US 5 692 769. The steering wheel assembly 22 further includes a retainer ring 36 and a clock spring housing 38. The clock spring housing 38 includes a cylindrical wall 40 having a locking notch 42.

The steering wheel assembly 22 further includes a rotor 46. The rotor 46 includes an outer cylindrical wall 48 and a concentric cylindrical inner wall 50 spaced radially inwardly from the outer wall 48. The outer wall 48 includes an orifice 52. As is well known in clock spring assemblies for steering wheel assemblies, a ribbon wire 54 is coiled about the outer wall 48 of the rotor 46. In the present invention, the ribbon wire 54 is coiled about the outer wall 48 and leads into the orifice 52 through the outer wall 48 for connection to a connector body, which will be described below. A plurality of tabs 56 for connection to the retainer ring 36 extend upwardly from the inner wall 50. The outer wall 48 of the rotor 46 is preferably integral with an annular, generally planar clockspring housing cover 58. The steering wheel assembly further includes a locking pin 62 having an upwardly extending locking finger 64 at one end and a ramp surface 66 at an opposite end 65.

The steering column assembly 24 comprises a steering shaft 70 having a threaded outer end 72 and a plurality of circumferentially spaced splines 74. The steering column assembly 24 further includes a collar assembly 76. The collar assembly 76 includes an inner cylindrical wall 78 and a concentric outer cylindrical wall 80 adjacent or spaced radially from the inner cylindrical wall 78. The outer cylindrical wall 80 includes an axial abutment surface 82 generally about the circumference of the axial outer end 84 of the outer wall 80. The axial abutment surface 82 tapers axially away from the axial outer end 84 to form an axial guide 86. A second axial guide 88 is circumferentially spaced from the axial guide 86, preferably by approximately 135 degrees. The collar assembly 76 further preferably includes a generally planar annular base 90 formed opposite the outer end 84. The base 90 preferably includes a plurality of circumferentially spaced apertures 92 for securing the collar assembly 76 to a surface. A first electrical connector 96 extends upwardly from the base 90 and is spaced radially outwardly from the outer wall 80. The first electrical connector 96 includes a plurality of pin sockets 98.

As can be seen in Figure 2, the inner wall 50 of the rotor 46 extends downwardly past the clockspring housing cover 58. Axially extending keys 102 are formed on the inner surface of the inner wall 50. A second electrical connector 104 is formed adjacent the inner wall 50 extending downwardly from the clockspring housing cover 58. The second electrical connector 104 includes a plurality of pins 106 matable to the pin sockets 98 (not shown) in the first electrical connector 96. The second electrical

connector 104 further preferably includes a locking notch 108.

As can be seen in Figure 3, the steering wheel assembly 22 is first assembled, preferably by assembling the steering wheel armature 28 and airbag assembly 30 (not shown in Figure 3) to the hub plate 32. Rotor 46 is rotatably mounted in the clockspring housing 38. The tabs 56 of the rotor 46 extend upwardly to the clockspring housing 38 and are secured by the retainer ring 36. Rotation of the steering wheel armature 28 and hub plate 32 relative to the second electrical connector 104 and rotor 46 is prevented by the locking pin 62. The locking finger 64 of the locking pin 62 is disposed within the locking notch 42 of the clockspring housing 38, while the opposite end 65 of the locking pin 62 is disposed within the locking notch 108 in the second electrical connector 104. The clockspring housing 38 is mounted to the hub plate 32. The steering column assembly is also assembled by inserting the steering shaft 70 through the collar assembly 76 and securing the collar assembly 76 to a surface 110, such as the steering column, dash or other surface which is non rotatable relative to the vehicle.

The steering wheel assembly 22 is then assembled onto the steering column assembly 24. First, the installer selects the steering wheel assembly 22 and brings it toward the steering column assembly 24 as shown in Figure 3. The inner wall 50 of the rotor 46 is roughly aligned with the outer wall 80 of the collar assembly 76. The outer wall 80 of the collar assembly 76 is then inserted into the inner wall 50 of the rotor 46 to a first position in which the keys 102 formed on the inner surface of the inner wall 50 of

the rotor 46 abut the abutment surface 82 of the outer wall 80 of the collar assembly 76.

The installer then rotates the steering wheel assembly 22 until he can feel the keys 102 are aligned with the axial guide 86,88. The keys 102 slide along the abutment surface 82 into the axial guides 86,88 as the installer rotates the steering wheel assembly 22 slightly and moves it forward axially to a second position in which the first electrical connector 96 is rotationally aligned with and begins to engage the second electrical connector body 104. Upon further axial movement of the steering wheel assembly 22 toward the steering column assembly 24, the pins 106 of the second electrical connector body 104 are inserted into the pin sockets 98 of the first electrical connector body 96.

After the first and second electrical connector bodies 96,104 are at least partially engaged, the first electrical connector body 96 contacts the ramped surface 66 of the locking pin 62 forcing the locking pin 62 radially outwardly, as shown in Figure 4. The locking finger 64 is thus no longer disposed within the locking notch 42 of the clockspring housing 38, thereby permitting relative rotation of the clockspring housing 38 and the second electrical connector body 104 formed on the rotor 46. The first electrical connector body 96 is fully engaged with the second electrical connector body 104 thereby connecting the ribbon wire 54 and any switches on the steering wheel assembly 22 to the vehicle via the first electrical connector body 96. The rotor 46 is rotationally locked with the collar assembly 76 because the keys 102 are disposed within the axial guides 86,88 of the collar assembly 76. The steering wheel armature 28 and hub plate 32 are then rotated to

properly align the hub plate 32 with the splines 74 on the shaft 70. The steering wheel assembly 22 is then secured to the steering column assembly 24, preferably by threading engaging a threaded gear (not shown) with the outer end 72 of the shaft 70 utilizing a worm tool.

It should be apparent, as an alternative embodiment, that the clockspring housing 38 could be formed on the steering column assembly 24. Further, the keys 102 and axial guides 86,88 could be formed on either the steering wheel assembly 22 or the steering column assembly 24. In the illustrated embodiments, the mating cylindrical surface of the steering wheel assembly 22 is the inner wall 50 of the rotor 46, and the mating cylindrical surface of the steering column assembly 24 is the outer wall 80 of the collar assembly 76. It should be apparent that the male mating cylindrical surface and female mating cylindrical surface could be formed on either the steering wheel assembly 22 or the steering column assembly 24.

The vehicle steering assembly 20 of the present invention provides improved installation of the steering wheel assembly 22 onto the steering column assembly 24. The mating cylindrical surfaces 50,80 align the steering wheel assembly 22 to the steering column assembly 24. The steering wheel assembly 22 is then rotationally aligned to the steering column assembly 24 by the keys 102 and the axial guides 86,88. The electrical connectors 96,104 are then properly aligned and are engaged upon further axial movement of the steering wheel assembly 22. The vehicle steering assembly 20 of the present invention facilitates the installation of the steering wheel assembly 22 and prevents damage to any electrical connections or wires between the steering wheel assembly 22 and the steering column assembly 24.