Patent Description:
A disc brake assembly having a sensor assembly is disclosed in <CIT>. <CIT> discloses a double friction lining wear sensor that has two sensor heads that are mountable to a friction lining carrier. <CIT> discloses a disc brake that has two brake pad wear sensors that are mountable a corresponding back plate of a brake pad and cables that extend from each brake pad wear sensor and are brought together at a combiner and lead as a single evaluation cable to an evaluation unit. <CIT> discloses a single friction lining sensor that is mountable to a pocket of a friction lining carrier plate of a brake pad.

A brake assembly is provided as set out in claim <NUM>.

The friction material may define a recess that extends away from the pad spring. The sensor unit may be at least partially received in the recess.

The sensor unit may include a front body that engages the front side of the backplate, a rear body that engages a rear side of the backplate that is disposed opposite the front side, and a bridge that extends from the front body to the rear body. The bridge may engage the backplate and the pad spring.

The front body may extend into the recess.

The front body may extend further away from the pad spring than the rear body extends from the pad spring.

The front body may have a front body protrusion that extends away from the friction material. The rear body may have a rear body protrusion. The pad spring may be received between the front body protrusion and the rear body protrusion.

A first sensor is encapsulated in the front body. The first sensor may provide a signal indicative of wear of the friction material.

The first sensor may provide a signal indicative of wear of the friction material.

A second sensor may be encapsulated in the sensor unit rearward of the front body. The second sensor may be encapsulated in the rear body. The second sensor may provide a signal indicative of temperature of the brake pad assembly.

A sleeve may extend from the sensor unit. The sleeve may encircle an electrical conductor that extends to a first sensor.

The sleeve may include a plurality of protrusions that extend away from the electrical conductor. The plurality of protrusions may be spaced apart from each other. The plurality of protrusions may encircle the electrical conductor.

The brake assembly may further comprise a coil member that is received inside the sensor unit and the sleeve. Coils of the coil member may extend around the electrical conductor.

The brake assembly may further comprise a second brake pad assembly that includes friction material disposed on a second backplate, a second pad spring that is mounted to the second backplate, a second sensor unit that straddles the second backplate and that extends from the second backplate to the second pad spring, and a connecting electrical conductor that electrically connects the sensor unit to the second sensor unit.

A connecting member may extend from the front body of the sensor unit to a front body of the second sensor unit.

The sensor unit may be moveably disposed on the connecting member.

A connecting member may extend from the sensor unit to the second sensor unit: The second sensor unit and the connecting member may be integrally formed. A brake pad retraction spring may extend from the backplate of the brake pad assembly to the second backplate of the second brake pad assembly. The brake pad retraction spring may bias the brake pad assembly and the second brake pad assembly away from each other. The brake pad retraction spring may include a coil. The connecting member may include a flange and a coil engagement feature that extends from the flange and through the coil to secure the coil between the flange and the coil engagement feature.

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 truck, bus, farm equipment, military transport or weaponry vehicle, or cargo loading equipment for land, air, or marine vessels. In at least one configuration, the brake assembly <NUM> includes first and second brake pad assemblies <NUM>, <NUM>, first and second pad springs <NUM>, <NUM>, and first and second sensor units <NUM>, <NUM>. The brake assembly <NUM> may be configured as a disc brake assembly and may include a brake carrier <NUM>, a brake caliper <NUM>, and a retainer strap <NUM>. Optionally, one or more brake pad retraction springs <NUM> may also be provided with the brake assembly <NUM>, examples of which are best shown in <FIG>.

Referring to <FIG>, the brake carrier <NUM> may facilitate mounting of the brake assembly <NUM>. For instance, the brake carrier <NUM> may be fixedly mounted to a component of the vehicle, such as an axle assembly or a knuckle. The brake carrier <NUM> may receive and support the brake pad assemblies <NUM> and may include an opening through which a brake rotor <NUM> (shown in phantom in <FIG> and <FIG>) may extend. For instance, the brake carrier <NUM> may cradle or support the bottom and lateral sides of a brake pad assembly <NUM>. In at least one configuration, the brake carrier <NUM> may straddle the brake rotor <NUM> and may help position brake pad assemblies <NUM> on opposite sides of the brake rotor <NUM>.

The brake caliper <NUM> may be mounted to the brake carrier <NUM> and may support various components of the brake assembly <NUM>. In addition, the brake caliper <NUM> may help position the brake pad assemblies <NUM> with respect to the brake rotor <NUM> to facilitate braking of the vehicle as will be discussed in more detail below. In at least one configuration, the brake caliper <NUM> 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 slidable along a pair of guide pins that may be fixedly disposed on the brake carrier <NUM>. The caliper housing <NUM> may receive or support various components that may facilitate actuation of a brake pad assembly <NUM>. For instance, the caliper housing <NUM> may support a tappet <NUM> that may protrude from an internal chamber of the caliper housing <NUM>.

The tappet <NUM> may extend from the caliper housing <NUM> toward the brake rotor <NUM> to engage a brake pad assembly <NUM>. The tappet <NUM> may be moveable along an axis with respect to the caliper housing <NUM> such that the tappet <NUM> may move toward and away from the brake rotor <NUM>. For instance, an actuator may extend the tappet <NUM> to actuate a brake pad assembly <NUM> that is disposed between the caliper housing <NUM> and the brake rotor <NUM> into engagement with the brake rotor <NUM>. A reaction force may then move the caliper housing <NUM> and caliper bridge <NUM> with respect to the brake carrier <NUM> to actuate a brake pad assembly <NUM> that is disposed between the caliper bridge <NUM> and the brake rotor <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.

The caliper bridge <NUM> may be fixedly positioned with respect to the caliper housing <NUM>. The caliper bridge <NUM> may be integrally formed with the caliper housing <NUM> or may be a separate component that is mounted to the caliper housing <NUM>. For example, the caliper bridge <NUM> may be coupled or secured 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 define a cavity <NUM>.

The cavity <NUM> may at least partially receive the brake pad assemblies <NUM> and the brake rotor <NUM>. The cavity <NUM> may be configured as a large through hole that may be encircled by the brake caliper <NUM>. A portion of the brake carrier <NUM> may extend into the cavity <NUM> and may help position the brake pad assemblies <NUM>. A brake pad assembly <NUM> may be inserted into the cavity <NUM> and installed on the brake carrier <NUM> or removed from the cavity <NUM> and the brake carrier <NUM> when the retainer strap <NUM> is removed.

Referring primarily to <FIG>, a pair of brake pad assemblies <NUM> may be received in the brake carrier <NUM>. The brake pad assemblies <NUM> may be disposed on opposite sides of the brake rotor <NUM> and may have similar or identical configurations. For convenience in reference, the brake pad assembly <NUM> that is disposed between the brake rotor <NUM> and the tappet <NUM> may be referred to as an inboard brake pad assembly while the brake pad assembly <NUM> that is disposed between the brake rotor <NUM> and the caliper bridge <NUM> may be referred to as an outboard brake pad assembly. Also for convenience in reference, the brake pad assemblies <NUM> may be referred to as a "first brake pad assembly" and a "second brake pad assembly" below. The first and second brake pad assemblies may be the inboard and outboard brake pad assemblies, respectively, or vice versa. In at least one configuration, a brake pad assembly <NUM> includes a backplate <NUM> and friction material <NUM>.

The backplate <NUM> may be a structural member of the 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 a metal alloy. The tappet <NUM> may engage the backplate <NUM> of the inboard brake pad assembly <NUM>. For instance, the tappet <NUM> may engage a rear side <NUM> of the backplate <NUM> of the inboard brake pad assembly <NUM> that faces away from the brake rotor <NUM> and that is disposed opposite a front side <NUM> of the backplate <NUM> and the friction material <NUM>. The rear side <NUM> of the backplate <NUM> of the outboard brake pad assembly <NUM> may engage the caliper bridge <NUM>. The backplate <NUM> may include a plurality of tabs or hooks that may facilitate mounting of a pad spring <NUM>. The tabs or hooks may protrude or extend from a top side of the backplate <NUM> and may extend away from an opposing bottom side of the backplate <NUM> that may engage the brake carrier <NUM>.

Referring to <FIG> and <FIG>, the backplate <NUM> may optionally have one or more holes <NUM> that may facilitate mounting of a brake pad retraction spring <NUM>. In at least one configuration, a hole <NUM> may be disposed above the friction material <NUM>.

The friction material <NUM> is disposed on the front side <NUM> of the backplate <NUM> and may face toward the brake rotor <NUM>. The friction material <NUM> may contact the brake rotor <NUM> during vehicle braking. The friction material <NUM> may define at least one recess <NUM>. The recess <NUM> may extend from a top side of the friction material <NUM> away from the pad spring <NUM>. The recess <NUM> may extend through the thickness of the friction material <NUM>. In at least one configuration, the recess <NUM> may be tapered along the thickness of the friction material <NUM> (e.g., the recess <NUM> may be tapered to become narrower as the recess <NUM> extends toward the backplate <NUM>), tapered vertically or radially (e.g., the recess <NUM> may be tapered to become narrower as the recess <NUM> extends downward or away from the pad spring <NUM>), or combinations thereof.

Referring to <FIG>, the retainer strap <NUM> may be removably mountable to the brake caliper <NUM>. For instance, the retainer strap <NUM> may be removed from the brake caliper <NUM> to facilitate removal or replacement of a brake pad assembly <NUM> and may be installed on the brake caliper <NUM> to inhibit removal of a brake pad assembly <NUM>. The retainer strap <NUM> may extend across the brake pad assemblies <NUM> and the cavity <NUM> of the brake caliper <NUM> to help retain the brake pad assemblies <NUM> in the brake carrier <NUM> when the retainer strap <NUM> is secured to the brake caliper <NUM>. The retainer strap <NUM> may engage or contact a pad spring <NUM> when the retainer strap <NUM> is installed and secured to the brake caliper <NUM>. A first end of the retainer strap <NUM> may be mounted to the caliper housing <NUM>. A second end of the retainer strap <NUM> that is disposed opposite the first end may be disposed on the caliper bridge <NUM> and may be secured to the caliper bridge <NUM>, such as with a fastener like a bolt.

A pad spring <NUM> may exert a biasing force against a component that is received in the cavity <NUM>, such as a brake pad assembly <NUM> or the tappet <NUM>. For instance, a pad spring <NUM> is mounted to a backplate <NUM> of a brake pad assembly <NUM>, the tappet <NUM>, or combinations thereof. In the configuration shown, three pad springs <NUM> are illustrated; however, it is contemplated that a lesser number of pad springs <NUM> may be provided. The pad springs <NUM> may be spaced apart from each other and may extend from the retainer strap <NUM> toward or into the cavity <NUM>. For instance, from the perspective shown in <FIG> the uppermost pad spring <NUM> may extend from the retainer strap <NUM> to the tappet <NUM>, the middle pad spring <NUM> may extend from the retainer strap <NUM> to the first brake pad assembly <NUM>, and the remaining pad spring <NUM> may extend from the retainer strap <NUM> to the second brake pad assembly <NUM>. A pad spring <NUM> may be secured to the tappet <NUM> or a backplate <NUM> in any suitable manner. For instance, as is best shown in <FIG>, a pad spring <NUM> may have opposing ends that engage the backplate <NUM> and that may be received in a notch that is formed in a tab, hook, or other protrusion that protrudes from a top side of the backplate <NUM>. As such, a pad spring <NUM> may generally extend the majority of the top side of the backplate <NUM>.

Referring to <FIG> and <FIG>, one or more sensor units <NUM> may be provided with the brake assembly <NUM>. A sensor unit <NUM> may be mounted to a brake pad assembly <NUM>. For instance, a sensor unit <NUM> straddles the backplate <NUM>, which may help retain the sensor unit <NUM> on the backplate <NUM> when the brake pad assembly <NUM> is actuated. A sensor unit that straddles the backplate <NUM> may not extend through an opening or open-ended slot that is provided in the backplate <NUM>. The sensor unit <NUM> extends from the backplate <NUM> to the pad spring <NUM>, which may help retain the sensor unit <NUM> on the backplate <NUM> and inhibit movement of the sensor unit <NUM> away from the brake carrier <NUM> and the bottom side of the backplate <NUM>. The sensor unit <NUM> may be partially received in the recess <NUM> of the friction material <NUM> which may allow the sensor unit <NUM> to engage the friction material <NUM> to limit circumferential movement of the sensor unit <NUM> with respect to the friction material <NUM>. In at least one configuration and as is best shown with reference to <FIG>, the sensor unit <NUM> includes a front body <NUM>, a rear body <NUM>, a bridge <NUM>, and one or more sensors, such as a first sensor <NUM> and a second sensor <NUM>. The sensor unit <NUM> may also include or be associated with one or more electrical conductors <NUM>, a sleeve <NUM>, and a coil member <NUM>.

Referring to <FIG> and <FIG>, the front body <NUM> engages the front side <NUM> of the backplate <NUM>. For instance, the front body <NUM> may contact and extend along a portion of the front side <NUM> of the backplate <NUM> where the friction material <NUM> is not present and into the recess <NUM> of the friction material <NUM>. At least a portion of the front body <NUM> may have a width that is smaller than the width of the recess <NUM> to facilitate insertion of the front body <NUM> into the recess <NUM>. Alternatively the front body <NUM> may contact and conform to the shape of the recess <NUM>. Moreover, tapering of the recess <NUM> may facilitate installation of the front body <NUM> while permitting the front body <NUM> to contact multiple sides or surfaces of the friction material <NUM> that define the recess <NUM> to help secure the front body <NUM>. The front body <NUM> may protrude from the front side <NUM> toward the brake rotor <NUM> and the friction material <NUM>. In at least one configuration, the front body <NUM> may have a thickness in a direction that extends away from the rear body <NUM> that may be less than or equal to the thickness of the friction material <NUM> when the friction material <NUM> is unworn. Optionally, the front body <NUM> may have a greater thickness than the rear body <NUM>. As is best shown in <FIG>, the front body <NUM> may extend further downward or further away from the pad spring than the rear body <NUM>. In at least one configuration, the front body <NUM> may include a front body protrusion <NUM>.

The front body protrusion <NUM> may be disposed proximate the pad spring <NUM>. The front body protrusion <NUM> may extend away from the friction material <NUM> or extend in an upward direction from the perspective shown. In at least one configuration, the front body protrusion <NUM> may be aligned with and may extend from a frontal side <NUM> of the front body <NUM> that faces away from the rear body <NUM>. The front body protrusion <NUM> may be disposed adjacent to a side of the pad spring <NUM> that faces toward the brake rotor <NUM> and may help locate the sensor unit <NUM> with respect to the pad spring <NUM>. Optionally, a side of the front body protrusion <NUM> that faces toward the pad spring <NUM> may engage the pad spring <NUM>.

The rear body <NUM> may be spaced apart from the front body <NUM>. The rear body <NUM> engages the rear side <NUM> of the backplate <NUM>. For instance, the rear body <NUM> may contact and extend along a portion of the rear side <NUM> of the backplate <NUM>. The rear body <NUM> may protrude from the rear side <NUM> of the backplate <NUM> away from the brake rotor <NUM> and the friction material <NUM>. The rear body <NUM> may have the same width or a different width than the front body <NUM>. In addition, the rear body <NUM> may be thicker than shown, which may provide a larger volume for receiving circuitry or other components. In at least one configuration, the rear body <NUM> may have a rear body protrusion <NUM>.

The rear body protrusion <NUM> may be spaced apart from the front body protrusion <NUM>. The rear body protrusion <NUM> may be disposed proximate the pad spring <NUM>. The rear body protrusion <NUM> may extend in an upward direction from the perspective shown. In at least one configuration, the rear body protrusion <NUM> may be aligned with and may extend from a rearward facing side <NUM> of the rear body <NUM> that faces away from the front body <NUM>. The rear body protrusion <NUM> may be disposed adjacent to a side of the pad spring <NUM> that faces away from the brake rotor <NUM> and may help locate the sensor unit <NUM> with respect to the pad spring <NUM>. Such, the pad spring <NUM> may be received between the front body protrusion <NUM> and the rear body protrusion <NUM>. Optionally, a side of the rear body protrusion <NUM> that faces toward the pad spring <NUM> may engage the pad spring <NUM>.

The bridge <NUM> may interconnect the front body <NUM> and the rear body <NUM>. For instance, the bridge <NUM> extends from the front body <NUM> to the rear body <NUM> and may extend across the backplate <NUM>. The bridge <NUM> engages the pad spring <NUM> and the backplate <NUM>. For instance, a top side <NUM> of the bridge <NUM> may face toward and may engage the pad spring <NUM> while a bottom side <NUM> of the bridge <NUM> may face toward and may engage a side of the backplate <NUM>, such as a top side of the backplate <NUM> that may face toward the retainer strap <NUM>. The top side <NUM> may be longer than the bottom side <NUM>. For instance, the top side <NUM> may have a length from the front body protrusion <NUM> to the rear body protrusion <NUM> that is greater than a length of the bottom side <NUM> from the front body <NUM> to the rear body <NUM>. The height of the bridge <NUM> from the top side <NUM> to the bottom side <NUM> may be less than the height of the front body <NUM> and the rear body <NUM>.

The bridge <NUM> may be integrally formed with the front body <NUM> and the rear body <NUM>. For instance, the front body <NUM>, rear body <NUM>, and the bridge <NUM> may be integrally formed of a polymeric material, such as silicone that can withstand the temperatures associated with braking while maintaining sufficient structural integrity (e.g., without melting). Moreover, such a material may limit heat absorption and help provide a degree of thermal insulation that may help protects sensors inside the sensor unit <NUM>.

Referring to <FIG>, sensors that may be provided with the sensor unit <NUM> will now be discussed. As an overview, at least one sensor is encapsulated in the sensor unit <NUM>. A sensor may be configured to provide a signal indicative of one or more attributes associated with the brake assembly <NUM>. As examples, the sensor may detect or provide a signal indicative of wear of the friction material <NUM>, temperature of the brake pad assembly <NUM>, or the like. Sensors will be discussed below with reference to a first sensor <NUM> and a second sensor <NUM> that are of different types or that have different configurations; however, it is contemplated that a greater or lesser number of sensors may be provided.

The first sensor <NUM> is encapsulated in the front body <NUM> of the sensor unit <NUM>. For instance, the first sensor <NUM> may be positioned between the frontal side <NUM> and an opposing back side <NUM> that faces toward the front side <NUM> of the backplate <NUM> when the front body <NUM> is unworn. The first sensor <NUM> may provide a signal indicative of wear of the friction material <NUM>. For example, the friction material <NUM> may contact the brake rotor <NUM> during braking, which may cause the friction material <NUM> to wear and decrease in thickness. After sufficient wear occurs, the side of the friction material <NUM> that faces toward the brake rotor <NUM> may be generally aligned with the frontal side <NUM> of the front body <NUM>. As a result, additional brake applications may result in engagement of the friction material <NUM> and the front body <NUM> with the brake rotor <NUM> and wear of both the friction material <NUM> and the front body <NUM>.

After sufficient wear occurs, the first sensor <NUM> or a portion thereof may be exposed and may contact the brake rotor <NUM> during braking and provide a signal that may be indicative of wear of the friction material <NUM> and that the brake pad assembly <NUM> should be replaced. For example, the signal may be generated by the first sensor <NUM> or may be associated with opening or closing an electrical circuit. For instance, the engagement of the brake rotor <NUM> with the first sensor <NUM> may sever or otherwise disconnect a normally continuous electrical circuit, resulting in a change to one or more electrical attributes, such as current or voltage, which may be detected or identified by an electronic controller that may receive the signal in a manner known by those skilled in the art. In <FIG>, the first sensor <NUM> is shown with a first sensor portion <NUM> and a second sensor portion <NUM>. The first sensor portion <NUM> is disposed closer to the frontal side <NUM> than the second sensor portion <NUM>. Sufficient wear of the front body <NUM> may result in wear of the first sensor portion <NUM> and in an open circuit associated with the first sensor portion <NUM> while operation of the second sensor portion <NUM> may be unaffected. Accordingly, the signal may be indicative of friction material wear to at least the first sensor portion <NUM>. Sufficient additional wear of the front body <NUM> may result in wear of the second sensor portion <NUM> and an open circuit associated with the second sensor portion <NUM>. Accordingly, the signal may be indicative of fiction material wear to at least the second sensor portion <NUM>. It is contemplated that a greater or lesser number of sensor portions may be provided. It is also contemplated that the first sensor portion <NUM> and second sensor portion <NUM> could represent different sensors rather than portions of the same sensor.

The second sensor <NUM> may also be encapsulated in the sensor unit <NUM>. In at least one configuration, second sensor <NUM> or portion thereof may be positioned further from the frontal side <NUM> than the first sensor <NUM>. For instance, the second sensor <NUM> or a portion thereof may be positioned rearward of the first sensor <NUM>, rearward of the front body <NUM>, or both. For example, the second sensor <NUM> may be positioned in or encapsulated in the bridge <NUM>, the rear body <NUM>, the sleeve <NUM>, or combinations thereof. Some examples of these locations are represented by circles shown in phantom in <FIG>. In at least one configuration, the second sensor <NUM> may provide a signal indicative of temperature of the brake pad assembly <NUM>. In such a configuration, the second sensor <NUM> may be of any suitable type, such as a thermocouple, thermistor, semiconductor temperature sensor, or the like. Positioning the second sensor <NUM> further away from the friction material <NUM> may help limit the amount of heat that is conducted to the second sensor <NUM> and may allow a less expensive temperature sensor with a more limited operating range to be used.

One or more electrical conductors <NUM> are electrically connected to the sensor or sensors provided with the sensor unit <NUM>. In electrical conductor <NUM> may be of any suitable type, such as a wire, ribbon, or the like. An electrical conductor <NUM> may be provided with an insulator or coating that may help withstand operating temperatures. For instance, in electrical conductor <NUM> may be lacquer-coated, which may also help reduce the amount of sheathing or insulating material provided around an electrical conductor <NUM>. One or more electrical conductors <NUM> may be associated with the first sensor <NUM> and the second sensor <NUM>. In <FIG>, electrical conductors <NUM> are represented by solid lines; however, it is to be understood that a solid line may represent more than one electrical conductor <NUM> so as to help form an electrical circuit.

The sleeve <NUM> may extend from the sensor unit <NUM>. In addition, the sleeve <NUM> may encircle one or more electrical conductors <NUM> and may encapsulate a portion of an electrical conductor <NUM> that is disposed inside the sleeve <NUM> as well as an insulator or coating that is provided with the electrical conductor <NUM>. The sleeve <NUM> may be integrally formed with the sensor unit <NUM>. For instance, the sleeve <NUM> may be molded or formed of the same material as the front body <NUM>, the rear body <NUM>, the bridge <NUM>, or combinations thereof. The sleeve <NUM> may extend from any suitable location on the sensor unit <NUM>. In the configuration shown in <FIG>, the sleeve <NUM> extends from the rear body <NUM> in a direction that extends away from the front body <NUM> and the bridge <NUM>; however, it is contemplated that the sleeve <NUM> may extend in a different direction or from a different side of the rear body <NUM>, may extend from the front body <NUM>, or may extend from the bridge <NUM>.

The sleeve <NUM> may include a plurality of protrusions <NUM> that may extend away from the electrical conductor <NUM>. The protrusions <NUM> may help limit or reduce the surface area of the sleeve <NUM> that may contact other components and thus help reduce the conduction of heat into the sleeve <NUM>, may increase the surface area available for cooling, or combinations thereof. A protrusion <NUM> may also help provide abrasion resistance to help protect the sensors and electrical conductors <NUM> inside the sensor unit <NUM>. In some circumstances, a protrusion <NUM> may help improve retention of the sleeve <NUM> in a desired location, such as when a protrusion <NUM> is compressed and secured inside a recess in another component of the brake assembly <NUM>, such as the brake caliper <NUM>, retainer strap <NUM>, or the like. In at least one configuration, the protrusions <NUM> may be spaced apart from each other and may encircle the electrical conductor <NUM>. For instance, the protrusions <NUM> may be configured as a generally circular discs that are axially spaced from each other when the sleeve <NUM> is not bent or is generally straight.

The coil member <NUM> may be received inside of the sensor unit <NUM> and the sleeve <NUM>. The coil member <NUM> may resemble an elongated coil spring and include a plurality of coils that may extend around or spiral around the electrical conductor <NUM>. At least a portion of the coil member <NUM> may be encapsulated in the sleeve <NUM> and may be encircled by one or more protrusions <NUM> if provided. In addition, a portion of the coil member <NUM> may be encapsulated in a portion of the sensor unit <NUM>. In the configuration shown, a first end of the coil member <NUM> is disposed in the rear body <NUM>; however, it is contemplated that the coil member <NUM> may have a greater length and may extend into and may be encapsulated in the bridge <NUM>, the front body <NUM>, or combinations thereof. A second end of the coil member <NUM> that is disposed opposite the first end may be located inside of the sleeve <NUM> or may extend out of the sleeve <NUM>. The coil member <NUM> may provide multiple functions. For example, the coil member <NUM> may help reinforce or strengthen the sleeve <NUM> or the connection between the sleeve and the rear body <NUM> to help prevent the sleeve <NUM> from tearing. The coil member <NUM> may also be bent to a desired angle, shape, or orientation to help route the electrical conductors <NUM> and the sleeve <NUM> in a desired manner. For instance, the coil member <NUM> may be curved or bent in a manner that helps route the electrical conductors <NUM> away from locations where pinching or damage may occur, such as away from one or more sides of moveable components such as the brake pad assembly <NUM> or the tappet <NUM>, and may then help maintain the desired shape, angle, or orientation. The coil member <NUM> may also provide strain relief that may inhibit inadvertent disconnection of an electrical conductor <NUM> and may help attenuate vibrations or inhibit vibration from damaging sensors or electrical connections.

As previously discussed, a single sensor unit <NUM> or multiple sensor units <NUM> may be provided with the brake assembly <NUM>. When multiple sensor units <NUM> are provided, the sensor units <NUM> may be disconnected from each other or connected to each other. For instance, multiple sensor units <NUM> may be provided on the same brake pad assembly <NUM> or different brake pad assemblies <NUM> without being physically connected at or near the brake assembly <NUM> when a disconnected configuration is provided. Multiple sensor units <NUM> may be provided on the same brake pad assembly <NUM> or different brake pad assemblies <NUM> and may be physically connected to each other at or near the brake assembly <NUM> in a connected configuration. Examples of connected sensor units <NUM> will be discussed below primarily in the context of configurations having two sensor units <NUM> in which one sensor unit <NUM> straddles or is mounted to a first brake pad assembly <NUM> while the other sensor unit <NUM> straddles or is mounted to the second brake pad assembly <NUM>. It is contemplated that sensor units may have a different number of sensors when multiple sensor units <NUM> are provided. For instance, a second sensor <NUM> may be provided with some but not all sensor units when multiple sensor units <NUM> are provided.

Referring to <FIG> a configuration is shown in which a first sensor unit <NUM> is disposed on a first brake pad assembly <NUM> while the second sensor unit <NUM> is disposed on the second brake pad assembly <NUM>. The first sensor unit <NUM> and the second sensor unit <NUM> are depicted as being aligned with each other and being disposed directly opposite each other; however, it is contemplated that the first sensor unit <NUM> and the second sensor unit <NUM> may be disposed in other positional arrangements. As is best shown in <FIG>, a connecting member <NUM> may extend from the first sensor unit <NUM> to the second sensor unit <NUM>. In at least one configuration, the connecting member <NUM> may extend from the front body <NUM> of the first sensor unit <NUM> to the front body <NUM> of the second sensor unit <NUM>. The connecting member <NUM> may be configured as a pliable or bendable member that may allow the first sensor unit <NUM> and the second sensor unit <NUM> to move toward each other when braking is applied (e.g., when the first brake pad assembly <NUM> and the second brake pad assembly <NUM> are actuated toward the brake rotor <NUM>) and may allow the first sensor unit <NUM> and the second sensor unit <NUM> to move away from each other when the brakes are released (e.g., when the first brake pad assembly <NUM> and the second brake pad assembly <NUM> move away from the brake rotor <NUM>). As such, the shape or orientation of the connecting member <NUM> may change during operation of the brake assembly <NUM>. In addition, the connecting member <NUM> may be provided with sufficient length to accommodate brake application and brake release regardless of the amount of wear of the friction material <NUM> (i.e., the connecting member <NUM> may accommodate unworn and fully worn brake pad assemblies). The connecting member <NUM> may be integrally formed with the first sensor unit <NUM>, the second sensor unit <NUM>, or both. For instance, the connecting member <NUM> may be molded with the first sensor unit <NUM> and the second sensor unit <NUM> to provide a unitary component.

Referring to <FIG>, the connecting member <NUM> may receive one or more connecting electrical conductors <NUM> that may extend between the first sensor unit <NUM> and the second sensor unit <NUM>. Such a connecting member <NUM> may be provided in various configurations. For instance, the connecting member <NUM> may be configured as a hollow tube through which one or more connecting electrical conductors <NUM> may extend. Alternatively or in addition, the connecting member <NUM> may be molded or formed around one or more connecting electrical conductors <NUM> such that the connecting member <NUM> contacts and encapsulates the connecting electrical conductors <NUM>.

Referring to <FIG>, one or more connecting electrical conductors <NUM> that extend between the first sensor unit <NUM> and the second sensor unit <NUM> may be disposed outside of the connecting member <NUM>. For instance, one or more connecting electrical conductors <NUM> may loop or spiral around the connecting member <NUM> or may be attached to the connecting member <NUM>. As such, the connecting member <NUM> may help support a connecting electrical conductor <NUM> in a manner that may help prevent pinching of an electrical conductor <NUM> or excessive bending of a connecting electrical conductor <NUM> that may break or damage the connecting electrical conductor <NUM>. The connecting member <NUM> may be solid or hollow in this configuration. Moreover, the connecting member <NUM> may flex during brake operation or may be configured to retain its shape. If the connecting member <NUM> retains its shape, a sensor unit <NUM> may slide along the connecting member <NUM> during brake application and release. For instance, the connecting member <NUM> may extend through a hole in a sensor unit <NUM> and may have a length that does not interfere with brake application or release.

Referring to <FIG> and <FIG>, a configuration is shown in which the connecting member <NUM>' may be mountable to a brake pad retraction spring <NUM>. As is best shown in <FIG>, one or more brake pad retraction springs <NUM> may be provided with the brake assembly <NUM>. A brake pad retraction spring <NUM> may facilitate retraction of the brake pad assemblies <NUM> away from the brake rotor <NUM> when braking force is not applied. As such, a brake pad retraction spring <NUM> may bias the brake pad assemblies <NUM> away from the brake rotor <NUM> and away from each other. In <FIG>, first and second brake pad retraction springs <NUM> are illustrated that may extend in opposite lateral directions from the retainer strap <NUM>, or to the left and right from the perspective shown in <FIG>. The brake pad retraction spring <NUM> may extend between the first brake pad assembly <NUM> and the second brake pad assembly <NUM>. For example, a brake pad retraction spring <NUM> may extend from the backplate <NUM> of the first brake pad assembly <NUM> to the backplate <NUM> of the second brake pad assembly <NUM>. It is to be understood one or more brake pad retraction springs <NUM> may be provided with a brake assembly having any of the configurations associated with <FIG>.

The brake pad retraction spring <NUM> may be provided in various configurations. As an example, a brake pad retraction spring <NUM> may include a first end <NUM>, a second end <NUM>, a coil <NUM>, a first arm <NUM>, and a second arm <NUM>.

The first end <NUM> may be mounted to a brake pad assembly <NUM>. For example, the first end <NUM> of the brake pad retraction spring <NUM> may be inserted into and may be received in the hole <NUM> of the backplate <NUM> of a brake pad assembly <NUM>.

The second end <NUM> may be disposed opposite the first end <NUM>. The second end <NUM> may be mounted to the other brake pad assembly <NUM>. For example, the second end <NUM> of the brake pad retraction spring <NUM> may be inserted into and may be received in the hole <NUM> of the backplate <NUM> of the other brake pad assembly <NUM>.

The coil <NUM> may be disposed between the first end <NUM> and the second end <NUM>. The coil <NUM> may engage the retainer strap <NUM>. For instance, the coil <NUM> may contact a side of the retainer strap <NUM> that may face toward the brake rotor <NUM> and the cavity <NUM> to inhibit movement of the coil <NUM> away from the brake rotor <NUM> or rotation of the brake pad retraction spring <NUM> away from the brake rotor <NUM>. The coil <NUM> may define a coil hole <NUM> that may extend around and may encircle a coil axis. The coil hole <NUM> and the coil axis may be encircled by one or more turns or spirals that make up the coil <NUM>. Such turns or spirals may be stacked or arranged along the coil axis with respect to each other.

The first arm <NUM> may extend from the coil <NUM> toward the first end <NUM>.

The second arm <NUM> may be spaced apart from the first arm <NUM>. The second arm <NUM> may extend from the coil <NUM> toward the second end <NUM>.

Referring to <FIG> and <FIG>, the connecting member <NUM>' may be mountable to the brake pad retraction spring <NUM>. For instance, the connecting member <NUM>' may be mountable to the coil <NUM>. A connecting electrical conductor <NUM> may be disposed inside or may be encapsulated by the connecting member <NUM>' in any of the manners previously discussed. In at least one configuration, the connecting member <NUM>' may include a flange <NUM> and a coil engagement feature <NUM>, which are best shown in <FIG>.

The flange <NUM> may extend from and may be integrally formed with the connecting member <NUM>'. In the configuration shown, the flange <NUM> is disposed proximate the center of the connecting member <NUM>' and is depicted as extending laterally from the connecting member <NUM>'. In at least one configuration, the flange <NUM> may enclose or encapsulate a reinforcement member, such as a wire mesh, plate, rod, or the like to increase stiffness of the flange <NUM> and/or the coil engagement feature <NUM>, which in turn may help transmit force during installation to help reduce installation effort.

The coil engagement feature <NUM> may extend from the flange <NUM>. The coil engagement feature <NUM> may be mountable or couplable to the coil <NUM> of the brake pad retraction spring <NUM> and/or couplable between the coil <NUM> and the retainer strap <NUM>. For instance, the coil engagement feature <NUM> may extend through the coil <NUM> of a brake pad retraction spring <NUM> to secure the connecting member <NUM>' to the brake pad retraction spring <NUM>. In at least one configuration, the coil <NUM> may be secured between the flange <NUM> and an enlarged head <NUM> of the coil engagement feature <NUM>. The enlarged head <NUM> may have a larger diameter than the inside diameter of the coil <NUM>. In addition, the enlarged head <NUM> may have a pointed or tapered configuration that may help position or center the coil engagement feature <NUM> with respect to the coil hole <NUM> and facilitate insertion of the enlarged head <NUM> into the coil hole <NUM>.

The coil engagement feature <NUM> may be inserted into the coil hole <NUM> from either the top side or bottom side of the coil <NUM>. In the configuration shown in <FIG>, the coil engagement feature <NUM> is illustrated as being insertable from the top side of the coil <NUM> such that the flange <NUM> may extend over the coil <NUM> and a portion of the flange <NUM> may extend between the coil <NUM> and the retainer strap <NUM>. As such, the connecting member <NUM>' may be routed over the brake pad retraction spring <NUM> so that the brake pad retraction spring <NUM> may support the connecting member <NUM>' and help prevent the connecting member <NUM>' from contacting the brake rotor <NUM> or being pinched between a brake pad assembly <NUM> and the brake rotor <NUM>.

It is also contemplated that a connecting member <NUM>' may be supported by or attached to the retainer strap <NUM>, such as via a clip, tray, or the like. It is also contemplated that an electrical conductor <NUM> may be routed around the cavity <NUM> of the brake caliper <NUM> rather than across the cavity <NUM> of the brake caliper <NUM>. In such a configuration, an electrical conductor <NUM> may be guided by one or more ribs that are mounted to or formed with the brake caliper <NUM>.

Referring to <FIG>, an example of a configuration is shown in which at least one sensor unit may be moveable with respect to a connecting member. One sensor unit <NUM>, such as the sensor unit that is mounted to the outboard brake pad assembly <NUM>, may be stationary and may be coupled to the connecting member <NUM>". Such coupling may be accomplished in any suitable manner, such as by providing a hole such as a blind hole in the sensor unit <NUM> that receives an end of the connecting member <NUM>". The other sensor unit <NUM>" may be moveable or slidable with respect to the connecting member <NUM>". As an example, the sensor unit <NUM>" may have a hole into which or through which the connecting member <NUM>" may extend. The end of the connecting member <NUM>" that is disposed closest to the sensor unit <NUM>" may be spaced apart from components like the caliper housing <NUM>, cover plate of the caliper housing <NUM>, and the tappet <NUM> to accommodate movement of the brake pad assemblies <NUM>. The connecting member <NUM>" may be solid or hollow and may be inflexible or substantially rigid.

It is contemplated that one sensor unit may be moveable or both sensor units may be moveable. In <FIG>, movement of the sensor unit <NUM>" is shown in phantom. For instance, the sensor unit <NUM>" may move with the inboard brake pad assembly <NUM> toward the brake rotor <NUM> when the tappet <NUM> is extended and thus slide along the connecting member <NUM>" toward the brake rotor <NUM>. The other sensor unit <NUM> may also move with the outboard brake pad assembly <NUM> to engage the brake rotor in response to the reaction force as previously described. It is noted that <FIG> does not show internal components of the sensor units for clarity.

Claim 1:
A brake assembly (<NUM>) comprising:
a first brake pad assembly (<NUM>) that includes friction material (<NUM>) disposed on a front side (<NUM>) of a first backplate (<NUM>);
a first pad spring (<NUM>) that is mounted to the first backplate (<NUM>);
a second brake pad assembly (<NUM>) that includes friction material (<NUM>) disposed on a second backplate (<NUM>);
a second pad spring (<NUM>) that is mounted to the second backplate (<NUM>);
a first sensor unit (<NUM>, <NUM>") that straddles the first backplate (<NUM>) and that extends from the first backplate (<NUM>) to the first pad spring (<NUM>);
a second sensor unit (<NUM>) that straddles the second backplate (<NUM>) and that extends from the second backplate (<NUM>) to the second pad spring (<NUM>); and
a connecting electrical conductor (<NUM>) that electrically connects the first sensor unit (<NUM>) to the second sensor unit (<NUM>);
wherein the first sensor unit (<NUM>, <NUM>'') includes a front body (<NUM>) that engages the front side (<NUM>) of the first backplate (<NUM>), a rear body (<NUM>) that engages a rear side (<NUM>) of the first backplate (<NUM>) that is disposed opposite the front side (<NUM>), and a bridge (<NUM>) that extends from the front body (<NUM>) to the rear body (<NUM>), wherein the bridge (<NUM>) engages the first backplate (<NUM>) and the first pad spring (<NUM>), characterized in that a first sensor (<NUM>) is encapsulated in the front body (<NUM>).