Patent Application
20060225974
The subject invention relates to a wheel end and axle assembly having an integrated brake spider where a camshaft and bracket assembly is removable from the wheel end and axle assembly without requiring removal of a wheel hub.
Wheel end assemblies are supported on opposing ends of a vehicle axle. The vehicle axle includes an axle housing that extends between the wheel end assemblies. Each wheel end assembly includes a brake assembly and a wheel hub supported on bearings for rotation relative to the axle housing. The brake assembly includes a brake drum that is mounted for rotation with the wheel hub and a brake spider that mounts non-rotating brake components to the axle housing.
Non-rotating brake components include brake shoes that are pivotally supported by anchor pins at one shoe end, and which are actuated by a camshaft at an opposite shoe end. The camshaft rotates to move the brake shoes into engagement with the brake drum to slow or stop a vehicle.
The brake spider includes a spider body having a central opening surrounded by a plurality of radially spaced apertures extending through the spider body. The brake spider is slid over one end of the axle housing through the central opening of the spider body. The brake spider is fastened to an axle housing flange with a plurality of fasteners that extend through the plurality of radially spaced apertures.
One portion of the spider body has a single circular opening for receiving the camshaft and another portion of the spider body includes a pair of circular openings for receiving the anchor pins. A camshaft bushing is installed within the single circular opening to rotatably support the camshaft. One end of the camshaft is slid through the camshaft bushing such that the cam is positioned to actuate the brake shoes. An opposite end of the camshaft is coupled to a brake actuator.
In order to service the camshaft, the brake drum and the wheel hub must both be removed from the vehicle axle. This is time consuming and expensive. Additionally, removing the wheel hub from the vehicle axle can adversely affect seal and bearing assemblies. This can lead to premature wear for various wheel end components.
Thus, there is a need for a wheel end configuration that allows removal of the camshaft for service operations without requiring removal of the wheel hub and/or brake drum.
A brake spider includes a spider body having a central opening that surrounds an axle housing. A slot is formed within the spider body to receive a camshaft and a camshaft bracket assembly. The slot is defined by a surface that does not completely surround the camshaft. The slot allows the camshaft to be removed from a wheel end without requiring removal of other wheel end components.
In one example, a wheel hub is mounted for rotation relative to the axle housing about a wheel axis of rotation. A brake drum is mounted for rotation with the wheel hub about the wheel axis of rotation. The brake drum defines a cavity in which the brake spider is mounted. The camshaft rotates about a camshaft axis of rotation to actuate a brake component, such as brake shoes for example, in response to a braking command. By positioning the camshaft and the camshaft bracket assembly within the slot of the brake spider, the camshaft and the camshaft bracket assembly can be removed for service as needed without having to remove the wheel hub.
The slot is defined by an inner surface that is discontinuous about the camshaft axis of rotation. In the example shown, the camshaft axis of rotation is parallel to and spaced apart from the wheel axis of rotation. The wheel axis of rotation defines a lateral direction and the camshaft is removable from the slot by moving the camshaft along a linear path that extends along a longitudinal direction.
The subject invention provides a simplified method and apparatus for removing a camshaft from a wheel end assembly that does not require a wheel hub to be removed. This reduces cost and labor, as well as reducing the potential for premature wear or damage to other wheel end components. These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.
An axle housing 10 is shown in
The brake spider 18 is configured to provide advantages for assembling and disassembling components to and from the axle housing 10 when compared to prior spider configurations. In the example shown, the axle housing 10 comprises a drive axle housing, however, it should be understood that any type of axle could utilize the brake spider 18.
The brake spider 18 includes a spider body 20 with a center opening 22. The center opening 22 surrounds the axle housing 10. Preferably, the spider body 20 is welded at 24 (see
The slot 26 is defined by an inner surface 34 that is discontinuous about the camshaft axis 32. The inner surface 34 extends less than three hundred and sixty degrees about the camshaft axis 32. In other words, when the camshaft 30 is received within the slot 26, the inner surface 34 does not completely surround the camshaft 30. The slot 26 is thus open to external surroundings at a gap 36, which allows the camshaft 30 to be easily moved into and out of the slot 26.
In the example shown, the inner surface 34 is defined as a U-shaped surface having a bottom surface portion 34a extending inwardly toward a center of the spider body 20 and a pair of leg surface portions 34b. The pair of leg surface portions 34b extend outwardly away from the center of the spider body 20. Distal ends of each leg surface portion 34b are spaced apart from each other to define the gap 36.
The brake spider 18 is installed within a wheel end assembly, shown generally at 40 in
In either configuration, a wheel hub 42 is supported on bearings 44 for rotation relative to the axle housing 10 about a wheel axis 46. A brake drum 48 is mounted for rotation with the wheel hub 42 about the wheel axis 46. The brake drum 48 defines a cavity 50 that receives a brake assembly that includes the brake spider 18.
The camshaft 30 includes a cam 52 at one end and is coupled to a brake actuator (not shown) at an opposite end. In response to a braking command, the brake actuator rotates the camshaft 30 about the camshaft axis 32 to cause the cam 52 to move the brake shoes into engagement with the brake drum 48.
A camshaft bracket 54 connects the camshaft 30 to the brake spider 18. The camshaft bracket 54 is shown as being bolted to the brake spider 18 in
The slot 26 allows the camshaft 30 to be removed from the wheel end assembly 40 without requiring removal of the wheel hub 42 from the wheel end assembly 40. This facilitates service and maintenance operations. With traditional spider configurations, the wheel hub 42 had to be removed from the wheel end assembly 40 before the camshaft 30 could be removed. This was labor intensive and resulted in significant cost and vehicle downtime.
In the example shown, the wheel axis 46 and the camshaft axis 32 are spaced apart from each other and are generally parallel to each other. The wheel axis 46 and the camshaft axis 32 define a lateral direction. The slot 26 allows the camshaft 30 to move relative to the brake spider 18 along a linear path that is generally transverse to the lateral direction. This linear path extends generally in a longitudinal direction. To remove the camshaft 30 from the brake spider 18, the camshaft 30 is moved longitudinally out of the slot 26, and is then removed from the wheel hub 42. Thus, the wheel hub 42 remains mounted to the axle housing 10 during service or maintenance operations for the camshaft 30.
Although a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.
