Integrated wheel end for a wheel suspension of a motor vehicle

[0001] The present invention is related to integrated wheel ends for wheel suspensions of motor vehicles.

[0002] Wheel ends and bearing assemblies for motor vehicles are known and have been widely used in the automotive industry for many years. A typical vehicle wheel end may include a bearing assembly which is disposed about a shaft and hub and mounted to a steering knuckle by means of fasteners or interference fittings. The bearing assembly is preloaded by a locking nut which secures the bearing assembly with the hub and the shaft.

[0003] Although current wheel end assemblies are adequate, wheel end manufacturers have been challenged with weight, mass, fretting, creeping, and bending issues. For example, during normal operation of the vehicle, in many cases, the wheel end axially moves or creeps along its rotational axis where bending is experienced. The results are undesirable. Moreover, many current designs of vehicle wheel ends include relatively high mass and volume.

[0004] Thus, it is one aspect of the present invention to provide an integrated wheel end assembly for a motor vehicle wherein volume and mass are reduced relative to current wheel end designs.

[0005] It is another aspect of the present invention to provide an integrated wheel end assembly having reduced creeping, fretting, and bending moments along its rotational axis during normal operation.

[0006] It is yet another aspect of the present invention to provide an integrated wheel end assembly which has improved durability and longevity.

[0007] In one embodiment of the present invention, the integrated wheel end assembly includes a rotor portion having a braking surface and an inside surface defining a center bore formed therethrough. The integrated wheel end assembly further includes a hub portion disposed in the center bore and has extensions to circumferentially connect the hub portion to the rotor portion. The hub portion has inboard and outboard sides and extensions which radially extend therefrom. The extensions are insert-casted to the rotor portion at the inside surface to radially connect the rotor portion about the hub portion. The hub portion has an inner joint wall formed therethrough which has a contour to define a joint bore for torque transfer about a rotational axis. The hub portion further has a collar which extends from the inner joint wall at the inboard side. The collar has inner and outer sides wherein the outer side has an outboard inner raceway formed thereon to house bearings and the inner side defines a receiving bore for rotation about the axis.

[0008] Further aspects, features and advantages of the invention will become apparent from consideration of the following description and the appended claims when taken in connection with the accompanying drawings.

[0019] The present invention generally provides an improved integrated wheel end assembly for a wheel suspension of a motor vehicle. The wheel end assembly includes a wheel end or wheel portion having a hub portion radially connected to a rotor portion by insert-casting. The hub portion has a receiving bore which receives an end portion of a half shaft or stub shaft for torque or load transfer. The hub portion includes an inboard extending collar which is disposed about the shaft and abuts an inboard inner race of a bearing assembly. In use, the collar reduces rotational movement of the wheel end to reduce fretting, creeping, coning, and bending at a connection joint of the wheel end and the drive shaft. A hub portion of the wheel end is also made of steel which allows a reduced volume and a lighter weight design of the wheel end assembly.

[0020] FIGS. 1a-2 illustrate an integrated wheel end assembly 10 for a wheel suspension of a motor vehicle in accordance with one embodiment of the present invention. As shown, the integrated wheel end assembly 10 includes a steering knuckle 12 including a body 14 having an inner wall 16 formed therethrough to define a center bore 18 of the body 14. The steering knuckle 12 further includes first and second knuckle arms 19a, 19b to be mounted to a strut or an upper control arm and a lower control arm (not shown), respectively, of the motor vehicle.

[0021] As shown in FIGS. 1a-2, the assembly 10 further includes a bearing assembly having an outer race 20 disposed on the inner wall 16 in the center bore 18. As shown, based on the configuration, the assembly 10 may be identified as a generation three or “GEN III” assembly. In this embodiment, the outer race 20 has an inboard outer raceway 22 and an outboard outer raceway 24 formed thereon. The bearing assembly further includes an inboard inner race 26 disposed in the center bore 18. The inboard inner race 26 has an inboard inner raceway 28 formed thereon and cooperates with the inboard outer raceway 22 of the outer race 20 to house bearings therein to allow axial rotation of a shaft. The inboard inner race 26 has a first receiving bore 30 formed therethrough to receive and be cooperate about a half shaft (as described in greater detail below), defining an axis of rotation.

[0022] The integrated wheel end assembly 10 further includes a half shaft 32 disposed through the first receiving bore 30 defining an axis of rotation. The half shaft 32 has a body portion 34 and an end portion 36 extending outboard from the body portion 34. The end portion 36 has a contour shape for transmitting torque or load to a wheel end (discussed below). The body portion 34 has an outer surface 38 about which the inboard inner race 26 is disposed for rotation about the axis.

[0023] In this embodiment, the drive shaft is a half shaft for a driven wheel. It is to be noted that the drive shaft 32 may be any conventional drive shaft for a driven or non-driven wheel end, e.g., stub shaft, without falling beyond the scope or spirit of the present invention.

[0024] The integrated wheel end assembly 10 further includes a wheel end 40 having inboard and outboard sides 42, 44. As shown in FIGS. 1a-3, wheel end 40 further includes a hub portion 46 and a rotor portion 48 radially connected to the hub portion 46. In this embodiment, the hub portion 46 has a plurality of extensions 50 radially extending therefrom and insert-casted to the rotor portion 48 to radially connect the hub portion 46 to the rotor portion 48.

[0025] The hub portion 46 has an inner joint wall 52 formed therethrough. The inner joint wall 52 has a contour shape formed thereon to define a connecting bore 54 in which the contour shape of the end portion 36 of the drive shaft 32 is disposed to transmit torque or load and rotate the wheel end or wheel portion 40 about the axis. The contour of the inner joint wall 52 cooperates with the contour of the end portion 36 to provide torque or load transfer about the axis of rotation when the half shaft is driven. In this embodiment, the contour of the inner joint wall 52 and the end portion 36 is a polygonal shape. As shown, the connecting bore 54 of the wheel end 40 mates with the polygonal shape of the end portion 36 for torque transfer.

[0026] The hub portion 46 has a collar 56 which extends from the inner joint wall 52 at the inboard side 42. As the end portion and the inner joint wall cooperate, the collar 56 receives the body portion 34 and abuts the inboard inner race 26. As described in greater detail below, when a locking nut tightens the assembly 10, a preload is defined on the wheel end assembly. As shown, the collar 56 has inner and outer sides 58, 60. The outer side 60 has an outboard inner raceway 62 formed thereon. The outer side 60 cooperates with the outboard outer raceway 24 of the outer race 20 to house balls 64 therein. The inner side 58 has an inner diameter defining a second receiving bore 66 to receive the body portion 34 of the half shaft 32 which rotates and transfers load to the wheel end at the inner joint wall 52.

[0027] As shown, assembly 10 further includes inboard and outboard cages 68, 70 separating the balls between inboard and outboard sides. As shown, assembly 10 further includes seals 72. Moreover, retaining ring 74 is housed within integrated wheel end assembly 10 to maintain load on the wheel end assembly. As shown, locking nut 78 secures washer 76 about thread 37 of half shaft 32 defining a load on the bearing assembly. As known in the art, wheel studs 80 are inserted through mounting holes 82 of hub portion 46 to mount vehicle wheels thereto.

[0028] In this embodiment, the hub portion is made of materials including steel and steel alloy. Such materials provide strength to the wheel end during torque transfer and allows a reduction of mass and volume. However, other suitable materials may be used without falling beyond the scope or spirit of the present invention. In this embodiment, the rotor portion may be made of materials including grey cast iron, aluminum, or aluminum alloy. However, any other suitable material may be used without falling beyond the scope or spirit of the present invention.

[0029] FIGS. 5a-5b illustrate another embodiment of the integrated wheel end in accordance with the present invention. In this embodiment, the integrated wheel end 140 has a hub portion 146 having an inner joint wall 152 with a spline contour. Thus, the contour shape of the end portion 136 and the contour shape of the inner joint wall 152 is a spline to matingly connect the end portion 136 with the inner joint wall 152 and to transfer load.

[0030] As shown, the components of the integrated wheel end assembly 110 are similar to the integrated wheel end assembly 10 in FIGS. 1a-1b. For example, the steering knuckle 12, the outer race 20, the shaft 32, and the wheel end 40 of assembly 10 are the same as steering knuckle 112, outer race 120, drive shaft 132, and wheel end 140 of assembly 110.

[0031] FIGS. 6a-7 illustrate another embodiment of the integrated wheel end assembly in accordance with the present invention. As shown, the components of the integrated wheel end assembly 210 are similar to the integrated wheel end assembly 10 in FIGS. 1a-1b. For example, the steering knuckle 12, the outer race 20, the shaft 32, and the wheel end 40 of assembly 10 are the same as steering knuckle 212, outer race 220, shaft 232, and wheel end 240 of assembly 210. However, in this embodiment, the shaft 232 includes an integral inboard portion 233 having an inboard inner raceway 237 formed thereon thereby eliminating a separate inner race as mentioned in the embodiment described above. A collar 256 extends from the inboard side 242 of wheel end 240 and abuts the integral inboard portion 233 when disposed about shaft 232. As shown, based on the configuration, the assembly may be identified as a generation four or “GEN IV” assembly.

[0032] In this embodiment, the integrated wheel end has a modified polygon connection. That is, the contour of the end portion 236 and the contour of the inner joint wall 252 is a modified polygon shape to matingly connect the end portion 236 with the inner joint wall 252. As a result, the wheel end assembly 210 of the present invention is lighter in weight, smaller in volume, and more efficient in load transfer. Moreover, the wheel end assembly 210 of the present invention has reduced axial movement including fretting, creeping, coning and bending movements providing improved performance of the vehicle.

[0033] Further aspects, features and advantages of the invention will become apparent from consideration of the following description and the appended claims when taken in connection with the accompanying drawings.