Patent Description:
A brake assembly is disclosed in <CIT>. <CIT> discloses a brake assembly comprising: a caliper housing having a cavity and a hole that extends from the cavity; a tappet that is moveable along an axis with respect to the caliper housing and adapted to engage a brake pad assembly; a piston that is rotatable about the axis and is at least partially received in the tappet, wherein the piston and tappet have mating threads; a wear adjuster mechanism comprising an end cap, the end cap being fixedly mounted to the piston and the wear adjuster mechanism being at least partially received inside the piston, the wear adjuster mechanism including a shaft that is rotatable about the axis, wherein the shaft defines a shaft cavity that extends from a first end of the shaft that faces toward the end cap to a second end of the shaft that is disposed opposite the first end. <CIT> discloses also a method for adjusting the brake assembly, the method comprising: inserting a tool (screwdriver) through the through hole in the caliper housing and into the shaft cavity of the shaft of the wear adjuster mechanism that is configured to adjust a running clearance of a brake pad assembly; engaging the tool with the end cap that is fixedly mounted to the piston; rotating the tool to rotate the piston to manually adjust a position of the tappet with respect to the piston; and removing the tool from the shaft cavity and the caliper housing after rotating the tool. <CIT> discloses a disc brake that has a splined shaft that has a hexagonal recess. <CIT> discloses a power screw disc brake that has a shaft portion that is provided with a fitting at an inner end. <CIT> discloses a disc brake that has a screw-driver socket formed in a strut. <CIT> discloses a parking brake assembly that has a hex-opening in an end of a shaft.

In at least one embodiment, a method of adjusting a brake assembly is provided as set out in claim <NUM>.

In at least one embodiment, a brake assembly is provided as set out in claim <NUM>.

Referring to <FIG>, an example of a brake assembly <NUM> is shown. The brake assembly <NUM> may be provided as part of a vehicle, such as a motor vehicle like a truck, bus, farm equipment, military transport or weaponry vehicle, or cargo loading equipment for land, air, or marine vessels. The brake assembly <NUM> may be configured as a disc brake. In at least one configuration, the brake assembly <NUM> may include a brake carrier <NUM>, a brake caliper <NUM>, a pair of brake pad assemblies <NUM>, and optionally a retainer bracket <NUM>. Referring primarily to <FIG> and <FIG>, the brake assembly <NUM> may include components that may facilitate movement of the brake pad assemblies <NUM>, such as a brake actuator <NUM>, an operating shaft <NUM>, a yoke <NUM>, a tappet <NUM>, a piston <NUM>, and a wear adjuster mechanism <NUM>.

Referring to <FIG>, the brake carrier <NUM> may be fixedly mounted to the vehicle. For example, the brake carrier <NUM> may be directly or indirectly mounted to an axle assembly or a steering knuckle. The brake carrier <NUM> may receive and support the brake pad assemblies <NUM> in a manner that permits the brake pad assemblies <NUM> to move along an axis toward and away from the brake rotor <NUM> while inhibiting rotation of the brake pad assemblies <NUM> about the axis. The brake carrier <NUM> may include a rotor opening that may receive a brake rotor <NUM>. As such, the brake carrier <NUM> may straddle the brake rotor <NUM> and help position the brake pad assemblies <NUM> on opposite sides of the brake rotor <NUM>.

Referring to <FIG> and <FIG>, the brake caliper <NUM> may receive various components of the brake assembly <NUM>. In addition, the brake caliper <NUM> may facilitate positioning of the brake pad assemblies <NUM> with respect to the brake rotor <NUM> to facilitate braking of the vehicle. In at least one configuration, the brake caliper <NUM> may be mounted to the brake carrier <NUM> and may include a caliper housing <NUM> and a caliper bridge <NUM>.

The caliper housing <NUM> may be moveably disposed on the brake carrier <NUM>. For example, the caliper housing <NUM> may be slidably disposed on a pair of guide pins that may be fixedly disposed on the brake carrier <NUM>. As is best shown in <FIG>, the caliper housing <NUM> may facilitate mounting of the brake actuator <NUM> and defines a cavity <NUM>, may have an opening <NUM>, and has a hole <NUM>.

The cavity <NUM> may receive or partially receive various components that facilitate movement of the brake pad assemblies <NUM>, such as the operating shaft <NUM>, yoke <NUM>, tappet <NUM>, piston <NUM>, and the wear adjuster mechanism <NUM>. The cavity <NUM> may have an aperture that may face toward the brake rotor <NUM> and that may be at least partially enclosed by a cover plate <NUM> that may be fixedly mounted to the caliper housing <NUM>, such as with fasteners like bolts.

Referring to <FIG> and <FIG>, the opening <NUM> may extend from the cavity <NUM> through a back wall <NUM> of the caliper housing <NUM> that may face away from the brake carrier <NUM> and the brake rotor <NUM>. In at least one configuration, a shaft of the brake actuator <NUM> may extend through the opening <NUM> to facilitate actuation of the operating shaft <NUM>. The opening <NUM> may be disposed above an axis <NUM>.

The hole <NUM> may be a through hole that extends from the cavity <NUM> and may extend through the back wall <NUM> of the caliper housing <NUM>. The hole <NUM> may be spaced apart from the opening <NUM>. The hole <NUM> may be sized such that the tool may be insertable and removeable through the hole <NUM> without disassembly of various components of the brake assembly <NUM> that facilitate movement of the brake pad assemblies <NUM>, such as the wear adjuster mechanism <NUM>. The hole <NUM> may be disposed above a brake rotor axis of rotation <NUM> and below the axis <NUM>. For example, the hole <NUM> may be centered about a hole axis <NUM> that may be disposed above the brake rotor axis of rotation <NUM> and may be disposed below or may be otherwise offset from the axis <NUM>. The hole <NUM> may receive a plug as will be discussed in more detail below.

Referring to <FIG> and <FIG>, the caliper bridge <NUM> may be integrally formed with or may be fixedly disposed on the caliper housing <NUM>. For example, the caliper bridge <NUM> may be coupled to the caliper housing <NUM> with one or more fasteners, such as bolts. In at least one configuration, the caliper bridge <NUM> may cooperate with the caliper housing <NUM> to at least partially define an opening <NUM> that may facilitate insertion and removal of the brake pad assemblies <NUM>.

Referring to <FIG>, a pair of brake pad assemblies <NUM> may be received in and may be supported by the brake carrier <NUM>. The brake pad assemblies <NUM> may be disposed on opposite sides of the brake rotor <NUM> and may be engageable with the brake rotor <NUM> to slow rotation of the brake rotor <NUM> and an associated wheel about a brake rotor axis of rotation <NUM>. One brake pad assembly <NUM> may be positioned between the caliper housing <NUM> and the brake rotor <NUM> and may be referred to as an inboard brake pad assembly <NUM>. The brake pad assembly <NUM> located on the opposite side of the brake rotor <NUM> may be positioned between the caliper bridge <NUM> and the brake rotor <NUM> and may be referred to as an outboard brake pad assembly <NUM>. The brake pad assemblies <NUM> may include a backplate <NUM> and friction material <NUM>.

The backplate <NUM> may be a structural member of a brake pad assembly <NUM>. The backplate <NUM> may be configured as a generally flat plate and may be made of any suitable material, such as metal or a metal alloy. As is best shown in <FIG>, a side of the backplate <NUM> that faces away from the friction material <NUM> may engage or contact the tappet <NUM>.

The friction material <NUM> may be disposed on a side of the backplate <NUM> that may face toward the brake rotor <NUM>. The friction material <NUM> may contact the brake rotor <NUM> during vehicle braking.

Referring to <FIG>, the retainer bracket <NUM> may be removably mounted to the brake caliper <NUM>. For example, the retainer bracket <NUM> may extend across the brake pad assemblies <NUM> and the opening <NUM> in the brake caliper <NUM> to help retain the brake pad assemblies <NUM> in the brake carrier <NUM> when the retainer bracket <NUM> is secured to the brake caliper <NUM>. Conversely, the retainer bracket <NUM> may be detached from or removed from the brake caliper <NUM> to permit removal of the brake pad assemblies <NUM> or installation of the brake pad assemblies <NUM> via the opening <NUM>.

Referring to <FIG>, the brake actuator <NUM> may be mounted to the brake carrier <NUM>. In at least one configuration, the brake actuator <NUM> may be mounted to the back wall <NUM> of the caliper housing <NUM> and may have a brake actuator shaft that may extend through the opening <NUM> in the caliper housing <NUM>. The brake actuator shaft may engage the operating shaft <NUM> and may be moveable to rotate the operating shaft <NUM>.

Referring to <FIG>, <FIG> and <FIG>, the operating shaft <NUM> may transmit force from the brake actuator <NUM> other moveable components of the brake assembly <NUM>. In at least one configuration, the operating shaft <NUM> may generally be configured as an inverted "Y" and may include a lever <NUM>, a pair of cams <NUM>, and a tab <NUM>.

Referring to <FIG>, the lever <NUM> may extend from the cams <NUM> toward the opening <NUM>. The lever <NUM> may have a pocket that may receive an end of the brake actuator shaft.

Referring to <FIG> and <FIG>, the cams <NUM> may be spaced apart from each other such that a gap <NUM> is provided between the cams <NUM>. In at least one configuration, the cams <NUM> may have mirror symmetry with respect to each other. In at least one configuration, a cam <NUM> may include a concave recess <NUM> and a convex surface <NUM>.

The concave recess <NUM> may receive a corresponding roller <NUM>. The roller <NUM> may be supported by a corresponding arcuate surface in the cavity <NUM> of the caliper housing <NUM> and may be rotatable about a roller axis of rotation <NUM>, which is best shown in <FIG>.

The convex surface <NUM> may be disposed opposite the concave recess <NUM>. The convex surface <NUM> may engage a corresponding set of roller bearings <NUM> that may be disposed between the convex surface <NUM> and the yoke <NUM>. The rollers <NUM> and roller bearings <NUM> may facilitate rotation of the operating shaft <NUM> about an axis of rotation. The operating shaft axis of rotation may be disposed at a radial centerline of the convex surface <NUM>.

Referring to <FIG>, a tab <NUM> may extend from at least one of the cams <NUM> into the gap <NUM>. A ball pin <NUM> may be fixedly mounted to the tab <NUM> and may extend toward the wear adjuster mechanism <NUM> as will be discussed in more detail below. In at least one configuration, the ball pin <NUM> may have a generally spherical or rounded ball at its distal end.

Referring to <FIG>, <FIG> and <FIG>, the yoke <NUM> may be disposed between the operating shaft <NUM> and the piston <NUM>. In at least one configuration, the yoke <NUM> may include a concave surface <NUM>, an engagement surface <NUM>, and a through hole <NUM>.

The concave surface <NUM> may face toward the operating shaft <NUM> and may engage the roller bearings <NUM>.

The engagement surface <NUM> may be disposed opposite the concave surface <NUM>. The engagement surface <NUM> may engage or contact an end of the piston <NUM>.

The through hole <NUM> may be disposed proximate the center of the yoke <NUM> and may extend around an axis <NUM>. The through hole <NUM> may receive at least a portion of the wear adjuster mechanism <NUM>. The axis <NUM> may be offset from and may extend substantially parallel to the brake rotor axis of rotation <NUM>.

Referring to <FIG>, <FIG> and <FIG>, the tappet <NUM> is moveable along the axis <NUM> with respect to the caliper housing <NUM>. However, the brake carrier <NUM> may inhibit or prevent the tappet <NUM> from rotating about the axis <NUM>. The tappet <NUM> may protrude away from the cavity <NUM> of the caliper housing <NUM> and may have a generally hollow body that may include an inner female thread <NUM> and an engagement face <NUM>.

The inner female thread <NUM> may face toward the axis <NUM> and may extend around the axis <NUM>.

The engagement face <NUM> may face away from the cavity <NUM>. The engagement face <NUM> may engage or contact a brake pad assembly <NUM>. For example, the engagement face <NUM> may engage or contact a side of the backplate <NUM> that may be disposed opposite the friction material <NUM>.

Referring to <FIG>, <FIG> and <FIG>, the piston <NUM> is at least partially received inside the tappet <NUM>. The piston <NUM> may be moveable along the axis <NUM>. In addition, the piston <NUM> is rotatable about the axis <NUM>. In at least one configuration, the piston <NUM> may have a hollow tubular configuration that may include an outer female thread <NUM>, at least one recess <NUM>, and an end cap <NUM>. The brake assembly <NUM> may be provided with a single piston <NUM> in one or more configurations.

The outer female thread <NUM> may face away from the axis <NUM> and may extend around the axis <NUM>. The outer female thread <NUM> may mate with the inner female thread <NUM> of the tappet <NUM>. As such, the tappet <NUM> and the piston <NUM> may have mating threads.

Referring to <FIG> and <FIG>, at least one recess <NUM> may be provided in an inner surface of the piston <NUM> that may be disposed opposite the outer female thread <NUM> and that may face toward the axis <NUM>. In the configuration shown, two recesses <NUM> are provided that are disposed opposite each other and extend the length of the piston <NUM>. The recesses <NUM> may facilitate mounting of a disc pack of the wear adjuster mechanism <NUM> as will be discussed in more detail below.

Referring to <FIG>, <FIG> and <FIG>, the end cap <NUM> may be disposed at an end of the piston <NUM> that may face toward the brake pad assembly <NUM> and the tappet <NUM>. The end cap <NUM> may be integrally formed with the body of the piston <NUM> or may be provided as a separate component. In the configuration shown, the end cap <NUM> is provided as a separate component that may be received in the hollow body of the piston <NUM>. The end cap <NUM> is fixed to the piston <NUM> such that the piston <NUM> is not rotatable with respect to the end cap <NUM>. In at least one configuration, the end cap <NUM> may include an engagement feature <NUM>. The engagement feature <NUM> may have any suitable configuration. For instance, the engagement feature <NUM> may have a male configuration, a female configuration, or combinations thereof. In the configuration shown, the engagement feature <NUM> is illustrated as having a female configuration that is configured as a blind hole; however, it is contemplated that such an engagement feature may be configured as a through hole rather than a blind hole. The engagement feature <NUM> may have any suitable shape or cross-section that may be compatible with a tool as will be discussed in more detail below. For instance, the engagement feature <NUM> may have multiple sides (e.g., may be slotted or may have a configuration such as a cross, triangular, square, hexagonal, Torx®, etc.). In at least one configuration, the axis <NUM> may extend through the engagement feature <NUM>.

Referring to <FIG>, the wear adjuster mechanism <NUM> may be configured to maintain a desired running clearance between the brake pad assemblies <NUM> and the brake rotor <NUM> when the brake pad assemblies <NUM> are retracted. As an overview, the wear adjuster mechanism <NUM> may include a one-way clutch that may permit the axial position of a brake pad assembly along the axis <NUM> to be adjusted or move closer to the brake rotor <NUM> in response to wear of the friction material <NUM>. The wear adjuster mechanism <NUM> may be provided in various configurations, some examples of which are disclosed in <CIT>. The wear adjuster mechanism <NUM> is at least partially received inside the piston <NUM>. In at least one configuration and as is best shown with reference to <FIG>, <FIG> and <FIG>, the wear adjuster mechanism <NUM> includes a shaft <NUM> and may include a first bearing assembly <NUM>, a second bearing assembly <NUM>, a drum <NUM>, a disc pack <NUM>, a first biasing member <NUM>, and a second biasing member <NUM>.

Referring to <FIG>, <FIG> and <FIG>, the shaft <NUM> may be at least partially received in the cavity <NUM> of the caliper housing <NUM>. The shaft <NUM> may be disposed in the through hole <NUM> of the yoke <NUM> and inside the hole or cavity of the piston <NUM>. In addition, the shaft <NUM> may be spaced apart from the yoke <NUM> and the piston <NUM>. The shaft <NUM> is rotatable about the axis <NUM>, defines a shaft cavity <NUM>, and may have a ball pin engagement feature <NUM>.

The shaft cavity <NUM> may extend along the axis <NUM> and may be centered about the axis <NUM>. In at least one configuration, the shaft cavity <NUM> may be configured as a through hole that may extend along the axis <NUM> from a first end <NUM> of the shaft <NUM> to a second end <NUM> of the shaft <NUM> that may be disposed opposite the first end <NUM> of the shaft <NUM>. The first end <NUM> may face toward the end cap <NUM> and may face away from the hole <NUM> in the caliper housing <NUM>. The second end <NUM> may be disposed opposite the first end <NUM> and may face away from the end cap <NUM> and may face toward the hole <NUM>. The portion of the shaft cavity <NUM> that may be received inside the yoke <NUM> may have a larger diameter or may extend further from the axis <NUM> than a portion of the shaft cavity <NUM> that may be received inside the piston <NUM>.

The shaft cavity <NUM> may have any suitable configuration. For instance, the shaft cavity <NUM> may not have a constant cross-section or a constant diameter from the first end <NUM> to the second end <NUM>. For instance, the shaft cavity <NUM> may be sized or configured such that the shaft <NUM> is disposed closer to the axis <NUM> at the first end <NUM> than at the second end <NUM> or such that the shaft cavity <NUM> extends further from the axis <NUM> at the second end <NUM> than at the first end <NUM>. Such a configuration may facilitate insertion of a tool as will be discussed in more detail below. In at least one configuration, the shaft cavity <NUM> may have a first portion <NUM> and a second portion <NUM>.

The first portion <NUM> may have a different cross-sectional shape, a different size, or both, as compared to the second portion <NUM>. The first portion <NUM> may extend from the first end <NUM> or may be disposed closer to the first end <NUM> than the second portion <NUM>. In the configuration shown, the first portion <NUM> is illustrated as being disposed closer to the axis <NUM> than the second portion <NUM>. The first portion <NUM> may have any suitable shape. For instance, the first portion <NUM> may have a cylindrical configuration.

The second portion <NUM> may extend between the first portion <NUM> and the second end <NUM>. For instance, the second portion <NUM> may extend from an end of the first portion <NUM> toward the second end <NUM> or to the second end <NUM>. In the configuration shown, the second portion <NUM> is illustrated as being disposed further from the axis <NUM> than the first portion <NUM>. The second portion <NUM> may have any suitable shape. For example, the second portion <NUM> may have a tapered conical configuration that may become progressively larger or may increase in diameter in an axial direction that may extend from the first end <NUM> toward the second end <NUM>. As such, the shaft cavity <NUM> may be tapered between the first end <NUM> and the second end <NUM>. It is also contemplated that the second portion <NUM> may not have a tapered conical configuration that may have a different configuration that increase the size of the shaft cavity <NUM> or distance from the axis <NUM> at the second end <NUM> as compared to the first end <NUM>. For instance, the second portion <NUM> may include a plurality of different sized portions or step configuration in which the diameter of the shaft cavity <NUM> or distance from the axis <NUM> is greater at the second end <NUM> as compared to one or more portions that are axially positioned further from the second end <NUM>. In at least one configuration, the second portion <NUM> may have a greater axial length or extend further along the axis <NUM> than the first portion <NUM>. It is also contemplated that the first portion <NUM> may be omitted and the second portion <NUM> may extend to the first end <NUM> rather than to the first portion <NUM>.

Referring primarily to <FIG>, the ball pin engagement feature <NUM> may be configured to engage the ball pin <NUM>. The ball pin engagement feature <NUM> may be disposed at an end of the shaft <NUM> that may face toward the operating shaft <NUM> and may be offset from the axis <NUM>. In the configuration shown, the ball pin engagement feature <NUM> is configured as a recess that may receive the ball pin <NUM>. The ball pin <NUM> may extend at an angle with respect to the axis <NUM> such that rotation of the operating shaft <NUM> may cause the ball pin <NUM> to engage a side or surface of the ball pin engagement feature <NUM> in a manner that may rotate the shaft <NUM> about the axis <NUM>. It is also contemplated that the ball pin engagement feature <NUM> may have a male configuration and the ball pin <NUM> may have a female configuration in other configurations.

Referring to <FIG>, <FIG> and <FIG>, the first bearing assembly <NUM> may rotatably support the shaft <NUM>. The first bearing assembly <NUM> may be disposed proximate a first end of the shaft <NUM> and may receive the shaft <NUM>. For instance, the first bearing assembly <NUM> may extend around the shaft <NUM> and may be received inside the piston <NUM>. As such, the first bearing assembly <NUM> may extend from the shaft <NUM> to or toward the inner surface of the piston <NUM>.

The second bearing assembly <NUM> may rotatably support the shaft <NUM>. The second bearing assembly <NUM> may be disposed proximate a second end of the shaft <NUM> and may receive the shaft <NUM>. For instance, the second bearing assembly <NUM> may extend around the shaft <NUM> and may be received inside the through hole <NUM> of the yoke <NUM>. As such, the second bearing assembly <NUM> may extend from the shaft <NUM> to or toward the yoke <NUM>.

The drum <NUM> may be received inside the piston <NUM> and may be spaced apart from the piston <NUM>. The drum <NUM> may extend around and may receive a portion of the shaft <NUM>. In addition, the shaft <NUM> may be selectively rotatable about the axis <NUM> with respect to the drum <NUM> as will be discussed in more detail below. In at least one configuration, the drum <NUM> may have a hollow tubular construction that may include at least one recess <NUM>. As is best shown in <FIG>, a plurality of recesses <NUM> are arranged around an exterior side of the drum <NUM> that faces away from the axis <NUM>. The recesses <NUM> may extend from an end of the drum <NUM> that may face toward the tappet <NUM> toward an opposite end of the drum <NUM>. The recesses <NUM> may facilitate mounting of the disc pack <NUM>. As is best shown in <FIG>, axial movement of the drum <NUM> may be constrained by the shaft <NUM> and by a spacer <NUM> that may extend from an end of the drum <NUM> to the first bearing assembly <NUM>.

Referring to <FIG>, <FIG> and <FIG>, the disc pack <NUM> may selectively couple the piston <NUM> and the drum <NUM>. The disc pack <NUM> may include a plurality of discs that may include at least one outer disc <NUM> and at least one inner disc <NUM>. As is best shown in <FIG> and <FIG>, the outer discs <NUM> may have at least one tab <NUM> that may be received in a recess <NUM> of the piston <NUM>. As such, the outer discs <NUM> may be rotatable about the axis <NUM> with the piston <NUM>. The inner discs <NUM> may have at least one tab <NUM> that may be received in a recess <NUM> of the drum <NUM>. As such, the inner discs <NUM> may be rotatable about the axis <NUM> with the drum <NUM>. The outer discs <NUM> and the inner discs <NUM> may be arranged in an alternating order in an axial direction or in a direction that extends along the axis <NUM>. For instance, at least one inner disc <NUM> may be axially positioned between two adjacent outer discs <NUM> or vice versa. The piston <NUM> may be rotatable about the axis <NUM> with the drum <NUM> when the discs of the disc pack <NUM> are sufficiently compressed such that the outer discs <NUM> and the inner discs <NUM> do not slip with respect to each other. Conversely, the drum <NUM> may be rotatable with respect to the piston <NUM> when the discs of the disc pack <NUM> are not sufficiently compressed or when the outer discs <NUM> and the inner discs <NUM> slip with respect to each other.

Referring to <FIG>, <FIG> and <FIG>, the first biasing member <NUM> may exert a biasing force on the disc pack <NUM>. The first biasing member <NUM> may have any suitable configuration. For instance, the first biasing member <NUM> may be configured as a spring that may extend from the first bearing assembly <NUM> to the disc pack <NUM> and that may exert a biasing force on the disc pack <NUM> in a direction that may extend toward the yoke <NUM>. As such, the first biasing member <NUM> may compress the discs of the disc pack <NUM>.

The second biasing member <NUM> may selectively couple the shaft <NUM> and the drum <NUM>. The second biasing member <NUM> may have any suitable configuration. For example, the second biasing member <NUM> may be configured as a wrap spring that may be axially positioned between the disc pack <NUM> and the second bearing assembly <NUM>. The second biasing member <NUM> may be partially received inside the yoke <NUM> and may be partially received inside the piston <NUM>. The second biasing member <NUM> may extend around the shaft <NUM> and may extend around a portion of the drum <NUM>. The second biasing member <NUM> may be configured to slip and allow the shaft <NUM> to rotate with respect to the drum <NUM> and the piston <NUM> when the brake is released or braking is disengaged as will be discussed in more detail below.

One or more retraction springs may be provided to facilitate retraction of the brake pad assemblies <NUM>. A retraction spring may be received in the cavity <NUM> of the caliper housing <NUM> and may extend from the yoke <NUM> to the cover plate <NUM>. The retraction spring may be configured to actuate the yoke <NUM> away from the cover plate <NUM> since the cover plate <NUM> is fixed to the caliper housing <NUM>. As such, the retraction spring may urge the yoke <NUM> to move along the axis <NUM> in a direction that extends away from the brake rotor <NUM> and the cover plate <NUM>.

Referring to <FIG>, operation of the brake assembly <NUM> will now be described in more detail. As an overview, the brake assembly <NUM> may start in a retracted state in which braking of the vehicle is not requested. As such, the brake pad assemblies <NUM> may be retracted away from the brake rotor <NUM> and components of the brake assembly <NUM> may be positioned as shown. Braking may be initiated in response to a vehicle braking command, such as may be provided by an input device like a brake pedal or sensor that may trigger braking of the vehicle, such as an adaptive cruise control system or a proximity sensor that may detect an object or obstruction in front of the direction of travel of the vehicle. The brake actuator <NUM> may be operated to extend the brake actuator shaft, thereby rotating the operating shaft <NUM> about its axis of rotation in a first direction or a counterclockwise direction from the perspective shown. Rotation of the operating shaft <NUM> may move the yoke <NUM>, tappet <NUM>, piston <NUM>, wear adjuster mechanism <NUM>, and the inboard brake pad assembly <NUM> that is disposed adjacent to the tappet <NUM> along the axis <NUM> toward the brake rotor <NUM> or to the left from the perspective shown. Movement of the yoke <NUM> toward the brake rotor <NUM> may compress the retraction springs. In addition, rotation of the operating shaft <NUM> may cause the ball pin <NUM> to engage the ball pin engagement feature <NUM> of the shaft <NUM>, which may rotate the shaft <NUM> about the axis <NUM>. Once the inboard brake pad assembly <NUM> contacts the brake rotor <NUM> a reaction force may then move the brake caliper <NUM> with respect to the brake carrier <NUM> to actuate the outboard brake pad assembly <NUM> that is disposed between the brake rotor <NUM> and the caliper bridge <NUM> into engagement with an opposite side of the brake rotor <NUM> to help slow rotation of the brake rotor <NUM> and an associated vehicle wheel. Retracting the brake actuator shaft may allow the operating shaft <NUM> to rotate about its axis of rotation in a clockwise direction from the perspective shown, which in turn may allow the actuation sequence to proceed in reverse under the biasing force of the retraction springs.

Rotation of the operating shaft <NUM> may or may not result in adjustment of the running clearance between the brake pad assembly <NUM> and the brake rotor <NUM>. For example, rotation of the operating shaft <NUM> in the first direction may operate the wear adjuster mechanism <NUM> to extend the tappet <NUM> closer to the brake rotor <NUM> with respect to the piston <NUM> when the operating shaft <NUM> and the ball pin <NUM> rotate the shaft <NUM> about the axis <NUM> before the inboard brake pad assembly <NUM> contacts the brake rotor <NUM>. As such, the shaft <NUM> and the drum <NUM> may rotate together about the axis <NUM> due to the force exerted by the second biasing member <NUM>. Rotation of the drum <NUM> may cause the piston <NUM> to rotate about the axis <NUM> due to the coupling provided by the disc pack <NUM>. Rotation of the piston <NUM> may extend the tappet <NUM> (i.e., extend the tappet <NUM> further away from the yoke <NUM> and closer to the brake rotor <NUM>) due to the mating of the outer female thread <NUM> of the piston <NUM> and the inner female thread <NUM> of the tappet <NUM>. For example, rotation of the piston <NUM> may cause the tappet <NUM> to extend to the left from the perspective shown with respect to the piston <NUM> due to operation of the mating threads since the tappet <NUM> is inhibited from rotating about the axis <NUM> by the brake carrier <NUM>. Extension of the tappet <NUM> with respect to the piston <NUM> may stop when the inboard brake pad assembly <NUM> contacts the brake rotor <NUM>. For example, the torque required to rotate the piston <NUM> increases substantially when the inboard brake pad assembly <NUM> contacts the brake rotor <NUM> even when the brake actuator <NUM> continues to rotate the operating shaft <NUM> and hence continues to rotate the shaft <NUM>. As a result, the discs of the disc pack <NUM> may slip with respect to each other, thereby permitting rotation of the shaft <NUM> with respect to the piston <NUM>.

The wear adjuster mechanism <NUM> may operate to hold the tappet <NUM> in its adjusted position when the brake pad assemblies <NUM> are retracted. For example, when the brake actuator <NUM> is retracted the operating shaft <NUM> may rotate in a second direction that is disposed opposite the first direction, or clockwise from the perspective shown. The ball pin <NUM> may then rotate the shaft <NUM> in the opposite direction back to its previous rotational position. However, the force exerted by the disc pack <NUM> may exceed the force exerted by the second biasing member <NUM>. As a result, the disc pack <NUM> may inhibit rotation of the piston <NUM> about the axis <NUM> with respect to the drum <NUM> while the second biasing member <NUM> may slip or allow the shaft <NUM> to rotate about the axis <NUM> in the second direction with respect to the drum <NUM> and back to its previous position.

Rotation of the operating shaft <NUM> may not result in adjustment of the running clearance between the brake pad assembly <NUM> and the brake rotor <NUM> when the inboard brake pad assembly <NUM> contacts the brake rotor <NUM> before the operating shaft <NUM> and the ball pin <NUM> rotate the shaft <NUM> about the axis <NUM>. As previously discussed, the torque required to rotate the piston <NUM> increases substantially when the inboard brake pad assembly <NUM> contacts the brake rotor <NUM>. As a result, the discs of the disc pack <NUM> may slip with respect to each other as the operating shaft <NUM> rotates in the first direction, thereby permitting rotation of the shaft <NUM> with respect to the piston <NUM> while rotation of the piston <NUM> is opposed by the tappet <NUM> reacting against the brake rotor <NUM>. The wear adjuster mechanism <NUM> may operate to hold the tappet <NUM> in its current position when the brake pad assemblies <NUM> are retracted (e.g., the disc pack <NUM> may inhibit rotation of the piston <NUM> about the axis <NUM> while the second biasing member <NUM> may slip or allow the shaft <NUM> to rotate about the axis <NUM> and back to its previous position as previously described).

Referring to <FIG>, the cavity <NUM> inside the caliper housing <NUM> may be sealed from the surrounding environment to inhibit moisture or water from entering the cavity <NUM>. For example, the brake actuator <NUM> and the cover plate <NUM> may directly or indirectly seal against the caliper housing <NUM>, such as with an intervening seal or gasket that may facilitate sealing of a corresponding opening of the caliper housing <NUM>. Similarly, a flexible boot <NUM> may extend from the tappet <NUM> to the caliper housing <NUM> and/or the cover plate <NUM> to provide sealing between the tappet <NUM> and the caliper housing <NUM> while accommodating movement of the tappet <NUM>. In addition, the hole <NUM> in the caliper housing <NUM> may receive a component such as a plug <NUM> that may facilitate sealing of the hole <NUM>. The plug <NUM> may be coupled to the caliper housing <NUM> in any suitable manner, such as with mating threads, an interference fit, or with another component that helps secure the plug <NUM>.

Referring to <FIG>, a method of adjusting a brake assembly will now be described. The brake assembly <NUM> may be mounted on a vehicle when an adjustment is made.

First, the plug <NUM> may be removed from the hole <NUM> in the caliper housing <NUM>, thereby providing access to the cavity <NUM>. Removal of the plug <NUM> is best understood by comparing <FIG>, which shows the plug <NUM> installed in the hole <NUM>, with <FIG>, in which the plug <NUM> is not present.

Next, a tool <NUM> may be inserted as shown in <FIG>. The tool <NUM> may be inserted into the hole <NUM> in the caliper housing <NUM> and into the shaft cavity <NUM> of the shaft <NUM> of the wear adjuster mechanism <NUM>. For instance, the tool <NUM> may extend from outside the caliper housing <NUM> through the hole <NUM>, through the shaft cavity <NUM>, and to the end cap <NUM>. The tool <NUM> may be of any suitable type. For instance, the tool <NUM> may be a rod, lever, Allen wrench, screwdriver, Torx® wrench, ball driver, socket or the like. At least a portion of the tool <NUM> may extend along and may be rotatable about a tool axis <NUM>. In <FIG>, the tool <NUM> and the tool axis <NUM> are disposed in a nonparallel relationship with the axis <NUM>. Such a configuration may be provided when the hole <NUM> is not aligned with or is not centered about the axis <NUM>. The tool <NUM> may be rotatable about the tool axis <NUM> but may not be rotatable about the axis <NUM> when the tool axis <NUM> is offset from or is not coaxial with the axis <NUM>. It is also contemplated that the tool <NUM>, the tool axis <NUM>, or both may extend along the axis <NUM> in one or more embodiments, such as when the hole <NUM> is centered about the axis <NUM> or is sized such that the tool axis <NUM> can be coaxial with the axis <NUM>.

The tool <NUM> may be inserted such that the tool <NUM> may engage or contact the end cap <NUM>. For instance, an end of the tool <NUM> may mate with a corresponding engagement feature <NUM> of the end cap <NUM>. The tool <NUM> may have any configuration that may be compatible with the engagement feature <NUM>. As one example, the tool <NUM> may have a male configuration that may mate with and may be received in an engagement feature <NUM> on the end cap <NUM> that may have a female configuration. Alternatively, the tool <NUM> may have a female configuration that may mate with and may receive an engagement feature <NUM> of the end cap <NUM> that may have a male configuration. For instance, the tool <NUM> may be configured as a socket that may receive the engagement feature <NUM>.

Next, the tool <NUM> may be rotated about the tool axis <NUM>. Rotating the tool <NUM> about the tool axis <NUM> may rotate the end cap <NUM> and the piston <NUM> about the axis <NUM> when sufficient torque is provided to override the automatic operation of the wear adjuster mechanism <NUM>. Rotation of the piston <NUM> in turn may rotate the tappet <NUM> and hence may adjust the axial position of the tappet <NUM> with respect to the piston <NUM>. For instance, rotating the tool <NUM> in a first rotational direction about the tool axis <NUM> may extend the tappet <NUM> while rotating the tool <NUM> in a second rotational direction that may be disposed opposite the first rotational direction may retract the tappet <NUM>. The tool <NUM> may be rotated until a desired position of the tappet <NUM> is attained. The desired position of the tappet <NUM> may be determined or measured directly or indirectly. As one example, the tool <NUM> may be rotated until the side of the tappet <NUM> that faces toward the brake rotor <NUM> is a predetermined distance from the brake rotor <NUM>. Such rotation may occur when a brake pad assembly <NUM> is removed from or installed in the brake assembly <NUM>. As another example, the tool <NUM> may be rotated until the friction material <NUM> of a brake pad assembly <NUM> is a predetermined distance from the brake rotor <NUM>. The predetermined distance between the friction material <NUM> and an adjacent side of the brake rotor <NUM> when braking is not applied (e.g., when the brake actuator <NUM> is retracted) may be referred to as a running clearance. As such, rotating the tool <NUM> may facilitate manual adjustment of the running clearance between an installed brake pad assembly <NUM> and the brake rotor <NUM>. The running clearance may be manually adjusted when the brake assembly <NUM> is serviced or when one or more brake pad assemblies <NUM> are replaced. Manual adjustment may be accomplished by rotating the tool <NUM> by hand or by rotating the tool <NUM> with another tool or mechanism, such as a power tool like a power screwdriver, drill, or the like. The source of torque for rotating the tool <NUM> may be located outside of the caliper housing <NUM>.

Next, the tool <NUM> may be removed after adjustment is complete. For instance, the tool <NUM> may be disengaged from the end cap <NUM> and may be extracted back through and out of the shaft cavity <NUM> and the hole <NUM> in the caliper housing <NUM>.

Finally, the plug <NUM> may be reinstalled in the hole <NUM> after the tool <NUM> has been removed. Reinstalling the plug <NUM> may help isolate the cavity <NUM> from the surrounding environment. For instance, the plug <NUM> may help seal against the caliper housing <NUM> to prevent contaminants, such as water or particulates, from entering the cavity <NUM>.

The brake assembly and method described above may allow a brake assembly to be provided without a manual adjustment shaft that is a self-contained in the brake assembly or installed during initial assembly of the brake assembly, which may help reduce weight and may eliminate components that are needed to support such a shaft. Moreover, sealing of the caliper housing may be improved or simplified as sealing with respect to such an adjustment shaft may be eliminated. For instance, a static plug may replace a moveable or rotatable seal that may be associated with such an adjustment shaft. The brake assembly and method may allow a tool to be installed and rotated at various angles and may enable better access for making manual brake adjustments. Moreover, the tool may provide torque to a piston without intermediate gears. Furthermore, the potential for inadvertently adjusting is reduced as a tool must be intentionally installed for manual adjustments to be made.

Claim 1:
A method for adjusting a brake assembly (<NUM>) comprising:
inserting a tool (<NUM>) through a through hole (<NUM>) in a caliper housing (<NUM>) and into a shaft cavity (<NUM>) of a shaft (<NUM>) of a wear adjuster mechanism (<NUM>) that is configured to adjust a running clearance of a brake pad assembly (<NUM>), wherein the shaft (<NUM>) is at least partially received inside a piston (<NUM>) that is rotatable about an axis (<NUM>) and is at least partially received inside a tappet (<NUM>) that is adapted to engage the brake pad assembly (<NUM>);
engaging the tool (<NUM>) with an end cap (<NUM>) that is fixedly mounted to the piston (<NUM>);
rotating the tool (<NUM>) to rotate the piston (<NUM>) to manually adjust a position of the tappet (<NUM>) with respect to the piston (<NUM>); and
removing the tool (<NUM>) from the shaft cavity (<NUM>) and the caliper housing (<NUM>) after rotating the tool (<NUM>).