Patent Application
20160341266
This patent application relates to a brake assembly that may have a camshaft that may have a contact groove that may receive a cam roller.
A brake assembly having a camshaft is disclosed in U.S. Patent Publication No. 2014/0262643.
In at least one embodiment, a brake assembly is provided. The brake assembly may include a spider, a brake pad assembly that may be moveably disposed on the spider, a camshaft, and a cam roller. The camshaft may be disposed proximate the spider and may rotate about an axis to actuate the brake pad assembly. The camshaft may have an S-cam that may have an end surface, a first end wall, and a contact groove. The first end wall may extend from the end surface. The contact groove may extend from the first end wall and may be disposed closer to the axis than the first end wall. The cam roller may engage the S-cam and may support the brake pad assembly. The cam roller may be received in the contact groove when the camshaft is in a second rotational position.
In at least one embodiment, a brake assembly is provided. The brake assembly may include a spider, a brake pad assembly, a camshaft tube, a camshaft, and a cam roller. The brake pad assembly may be moveably disposed on the spider. The camshaft tube may be mounted to the spider. The camshaft may be disposed in the camshaft tube and may rotate about an axis to actuate the brake pad assembly. The camshaft may include a shaft and an S-cam. The shaft may be rotatably disposed in the camshaft tube and may have an outer shaft surface that may extend around the axis. The S-cam may be disposed proximate an end of the shaft. The S-cam may have an end surface, a first end wall, and a contact groove. The first end wall may have a first arcuate surface that may extend from the end surface. The contact groove may extend from the first end wall toward the shaft. The contact groove may be disposed closer to the axis than the first arcuate surface and the outer shaft surface. The cam roller may engage the S-cam and the brake pad assembly and may be not be received in the contact groove when the camshaft is in a first rotational position and may be received in the contact groove when the camshaft is rotated from the first rotational position to a second rotational position.
As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.
Referring to
The brake assembly 10 may be a friction brake that may be configured to slow or inhibit rotation of at least one associated wheel. In
The spider 20 may support components of the brake assembly 10. In addition, the spider 20 may facilitate mounting of the brake assembly 10 to the vehicle. For example, the spider 20 may be fixedly disposed on or fixedly positioned with respect to an axle assembly or a steering knuckle. In at least one embodiment, the spider 20 may include an opening 40 through which an axle and/or a spindle may extend. For example, a spindle may extend through the opening 40 and may support one or more wheel bearings that may support and facilitate rotation of a wheel. The spider 20 may also include at least one spider mounting hole 42, at least one anchor pin hole 44, and a camshaft opening 46, which is best shown in
A spider mounting hole 42 may facilitate mounting of the spider 20 to the vehicle. A plurality of spider mounting holes 42 may be arranged around the opening 40. Each spider mounting hole 42 may receive a fastener, such as a bolt, that may extend through the spider mounting hole 42 and couple the spider 20 to another component, such as an axle assembly or a steering knuckle.
The anchor pin hole 44 may receive an anchor pin 22 that may facilitate mounting and operation of a brake pad assembly 24 will be discussed in more detail below. In
The camshaft opening 46 may receive the camshaft 30 and optionally a portion of the bracket assembly 28. The camshaft 30 may extend through the camshaft opening 46 to engage one or more brake pad assemblies 24.
Referring to
One or more brake pad assemblies 24 may be provided to slow or inhibit the rotation of a wheel. In
The brake shoe 50 may be pivotally mounted to the spider 20 at a first end via an anchor pin 22. For example, the anchor pin 22 may be fixedly positioned with respect to the spider 20 and the brake shoe 50 may pivot about an outer surface or circumference of the anchor pin 22 when the brake pad assembly 24 is actuated. An opposite end of the brake shoe 50 may have a groove that may receive a cam roller 26 that may be configured to engage a cam of the camshaft 30.
The brake shoe 50 may be a structural member of a brake pad assembly 24 and may facilitate mounting of the brake pad assembly 24 to the spider 20. The brake shoe 50 may include a table 54 that may be configured to support the friction material 52 and at least one web 56.
Referring to
The friction material 52, which may also be called a brake lining, may be disposed on an outer surface of the table 54 and may face toward the brake drum. The friction material 52 may engage the brake drum during vehicle braking and may be spaced apart from the brake drum when the friction braking is not being applied.
The cam roller 26 may be disposed between the brake pad assembly 24 and the camshaft 30. For example, the cam roller 26 may engage the camshaft 30 and the brake shoe 50 and may support the brake pad assembly 24. A cam roller 26 may be associated with each brake pad assembly 24 and the cam rollers 26 may be disposed on opposite sides of the camshaft 30 and its axis of rotation. As is best shown in
The cam roller end surface 62 may be disposed at an end of the cam roller 26. In the embodiment shown, a pair of cam roller end surfaces 62 are provided that may be disposed at opposite ends of the cam roller 26 and extend from the cam roller axis 60. The cam roller end surface 62 may extend substantially perpendicular with respect to the cam roller axis 60. The cam roller 26 may be optional in one or more embodiments, such as when the brake shoe 50 directly engages the S-cam of the camshaft 30. Alternatively, the cam roller 26 may be part of the brake shoe 50 and may not rotate with respect to the brake shoe 50, thereby resulting in sliding contact rather than a rolling contact with the camshaft 30.
The brake shoe engagement surface 64 may engage and support the brake shoe 50 of the brake pad assembly 24. In
The intermediate surface 66 may be disposed between the brake shoe engagement surface 64 and the cam engagement surface 68. In
The cam engagement surface 68 may engage the camshaft 30. The cam engagement surface 68 may be axially disposed between the pair of brake shoe engagement surfaces 64 and/or between the pair of intermediate surfaces 66. The cam engagement surface 68 may extend continuously around the cam roller axis 60. The cam engagement surface 68 may be an outer circumferential surface of the cam roller 26 that may be radially disposed with respect to the cam roller axis 60. The cam engagement surface 68 may have a larger diameter than the brake shoe engagement surface 64 and the intermediate surface 66. As is best shown in
The first step surface 70 may extend from the brake shoe engagement surface 64 to the intermediate surface 66. The first step surface 70 or a portion thereof may extend substantially perpendicular to the cam roller axis 60 in one or more embodiments. In
The second step surface 72 may extend from the intermediate surface 66 to the cam engagement surface 68. The second step surface 72 or a portion thereof may extend substantially perpendicular to the cam roller axis 60 in one or more embodiments. In
Referring to
The mounting flange 80 may facilitate mounting of the bracket assembly 28 to the spider 20. The mounting flange 80 may be spaced apart from the brake wing 82 and may be fixedly coupled to the camshaft tube 84.
The brake wing 82 may be coupled to the camshaft tube 84 and may support an actuator that may actuate or rotate the camshaft 30 about the axis 88. The brake wing 82 may be spaced apart from the spider 20 and may be fixedly coupled to the camshaft tube 84 opposite the mounting flange 80.
The camshaft tube 84 may extend from the mounting flange 80 to the brake wing 82. The camshaft tube 84 may have a generally tubular configuration and may define at least a portion of the hole 86 through which the camshaft 30 may extend. The camshaft tube 84 may interconnect the mounting flange 80 and the brake wing 82 and may be disposed around the axis 88
Referring to
The shaft 90 may be rotatably disposed in the camshaft tube 84 and may extend along the axis 88. The shaft 90 may have a first end and a second end that may extend out of opposite ends of the camshaft tube 84. The first end of the camshaft 30 may be disposed proximate and may engage a slack adjuster that may compensate for brake wear or wear of the friction material 52. For example, the slack adjuster may have a mounting hole that may receive the first end of the camshaft 30. The slack adjuster may be coupled to an actuator that may actuate the camshaft 30 about the axis 88. The actuator may move between a retracted position and an extended position. In the extended position, the actuator may rotate the camshaft 30 in a first rotational direction about the axis 88 toward a first rotational position as shown in
As is best shown in
Referring to
An end surface 102 may be disposed at an end of the S-cam 92. The end surface 102 may at least partially define each cam arm 100 and extend away from the axis 88 or generally perpendicular to the axis 88. In at least one embodiment, each cam arm 100 may extend the end surface 102 and may have a first end wall 104, a second end wall 106, and a contact groove 108.
The first end wall 104 may be disposed proximate the end surface 102. For example, the first end wall 104 may extend from the end surface 102 and may be at least partially defined by the end surface 102. The first end wall 104 may at least partially define the contact groove 108. The first end wall 104 may also include or may be at least partially defined by a first arcuate surface 110 and a first side surface 112.
The first arcuate surface 110 may extend from the end surface 102 toward the shaft 90. The first arcuate surface 110 or a portion thereof may be disposed substantially perpendicular to the end surface 102 and/or extend substantially parallel to the axis 88 in one or more embodiments. As is best shown in
The first side surface 112 may extend from the first arcuate surface 110 toward the axis 88. In addition, the first side surface 112 may face toward the second step surface 72 of a corresponding cam roller 26. The first side surface 112 may be spaced apart from and may not engage the second step surface 72 when the camshaft 30 is in a nominal or normal axial position or position along the axis 88; however, it is contemplated that the first side surface 112 may engage a portion of the first end wall 104, such as the first side surface 112, to inhibit axial movement of the camshaft 30 with respect to the cam roller 26 or vice versa. For instance, the first side surface 112 may engage the second step surface 72 if the camshaft 30 to the left from the perspective shown in
The second end wall 106, if provided, may be disposed proximate the shaft 90. For example, the second end wall 106 may extend from the shaft 90 toward the first end wall 104. The second end wall 106 may at least partially define the contact groove 108. The second end wall 106 may also include or may be at least partially defined by a second arcuate surface 120 and a second side surface 122.
The second arcuate surface 120 may extend from the shaft 90 toward the end surface. The second arcuate surface 120 may have substantially the same profile as the first arcuate surface 110 and may be aligned with or disposed substantially parallel to the first arcuate surface 110. As such, the second arcuate surface 120 or a portion thereof may be disposed extend substantially parallel to the axis 88 in one or more embodiments. As is best shown in
The second side surface 122 may extend from the second arcuate surface 120 toward the axis 88. The second side surface 122 may be disposed opposite the first side surface 112 and may face toward the second step surface 72 of a corresponding cam roller 26. The second side surface 122 may be spaced apart from and may not engage the second step surface 72 when the camshaft 30 is in a nominal or normal axial position or position along the axis 88; however, it is contemplated that the second side surface 122 may engage a portion of the second end wall 106, such as the second step surface 72, to inhibit axial movement of the camshaft 30 with respect to the cam roller 26 or vice versa. For instance, the second side surface 122 may engage the second step surface 72 if the camshaft 30 to the right from the perspective shown in
The contact groove 108 may be configured as a groove or recess that may be provided in the S-cam 92 and that may extend toward the axis 88. The contact groove 108 may be at least partially defined by the first end wall 104 and the second end wall 106. For example, a contact surface 130 may extend from the first end wall 104 to the second end wall 106 to define a bottom of the contact groove 108. For example, the contact surface 130 may be a concave surface that may extend from the first side surface 112 to the second side surface 122. The contact groove 108 may be disposed closer to the axis 88 than the first end wall 104 and/or the second end wall 106. For instance, the contact groove 108 may be recessed with respect to the first arcuate surface 110 and the second arcuate surface 120 such that the contact surface 130 may be disposed closer to the axis 88 than the first arcuate surface 110 and the second arcuate surface 120. As is best shown in
Referring to
In
In
In
The camshaft 30 may be rotated about the axis 88 from the second rotational position toward the first rotational position to brake a vehicle wheel. Rotation of the camshaft 30 in a first rotational direction from the position shown in
Providing a camshaft 30 with an S-cam that has a contact groove may allow additional friction material to be provided with a brake pad assembly as compared to a camshaft that does not have a contact groove. More specifically, the contact groove may allow the contact surface to be located closer to the axis and the S-cam base radius, which may allow a brake pad assembly to move closer to the axis or be retracted a greater distance from the brake drum as compared to similarly configured S-cam that does not have a contact groove. The greater retraction distance of the brake pad assembly may allow additional friction material or friction material having a greater thickness to be provided without changing the size or configuration of the brake shoe and without changing the size or configuration of the brake drum. Providing additional friction material may increase brake pad assembly life or the amount of braking cycles that can be executed prior to replacement, thereby reducing servicing intervals and maintenance costs.
While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.
