Patent Application
20250189000
The present application relates generally to a disc brake system, and in particular to a disc brake system including an torque plate having integral mounting and carrier portions, together with methods for the use and assembly thereof.
Disc brake systems may be configured with opposing pairs of brake pads that engage a rotor to slow and/or stop a vehicle. In operation, a moment is created between a brake pad drag force and an abutment force, which may lead to a greater amount of pressure being applied to the leading edge of the brake pad during braking. This uneven pressure distribution may lead to tapered pad wear, where the leading end of the brake pad friction material wears away faster than the trailing end. As such, the brake pads do not wear evenly and may need to be replaced more frequently.
The loads applied to the brake pads are typically absorbed by a carrier mechanically coupled to a torque plate. The assembly of the carrier and torque plate requires installation of various fasteners, and may adversely affect the positioning of the caliper and/or brake pads. The carrier and torque plate may include wide platforms to accommodate the fasteners, or require lateral clearance for the fasteners. Moreover, the carrier is configured with an outboard beam, which is necessary to locate and stabilize carrier horns, which prevents any deflection thereof. The increased weight of the carrier and torque plate, and requisite fasteners, increases the overall cost of the system and the associated assembly times.
The present invention is defined by the following claims, and nothing in this section should be considered to be a limitation on those claims.
In one aspect, one embodiment of a disc brake system includes a torque plate having a mounting portion with an opening shaped to receive a vehicle axle and a carrier portion integrally formed with the mounting portion as a one-piece unit. The carrier portion includes an inboard leading pad support, an inboard trailing pad support, an outboard leading pad support, and an outboard trailing pad support. The inboard leading and trailing pad supports are spaced apart and define an inboard pad receiving opening, and the outboard leading and trailing pad supports are spaced apart and define an outboard pad receiving opening. At least one of the inboard and/or outboard leading pad supports includes a first bearing surface facing away from a corresponding one of the inboard and/or outboard receiving openings. An inboard brake pad is disposed in the inboard pad receiving opening and an outboard brake pad is disposed in the outboard pad receiving opening. At least one of the inboard and/or outboard brake pads includes a second bearing surface facing toward the first bearing surface on the carrier pad supports and the corresponding one of the inboard and/or outboard receiving openings. The first and second bearing surfaces are configured to engage when the disc brake system is actuated such that at least a portion of the at least one inboard and/or outboard brake pads is put in tension.
In another aspect, one embodiment of a torque plate for a disc brake system includes a mounting portion with an opening shaped to receive a vehicle axle and a carrier portion integrally formed with the mounting portion as a one-piece unit. The carrier portion includes an inboard leading pad support, an inboard trailing pad support, an outboard leading pad support, and an outboard trailing pad support. The inboard leading and trailing pad supports are spaced apart and define an inboard pad receiving opening, and the outboard leading and trailing pad supports are spaced apart and define an outboard pad receiving opening. At least one of the inboard and/or outboard leading pad supports includes a slot defining a bearing surface facing away from a corresponding one of the inboard and/or outboard receiving openings.
In another aspect, one embodiment of a method of actuating a disc brake system includes engaging a rotor rotating about an axis with inboard and outboard brake pads, applying a tension force to a leading end of at least one of the inboard and/or outboard brake pads in response to the engaging of the rotor, and absorbing the tension force with a carrier portion of a torque plate. The carrier portion is integrally formed with a mounting portion as a one-piece unit, wherein the mounting portion has an opening centered about the axis and shaped to receive a vehicle axle.
Various other methods of using and assembling the disc brake system are also provided.
The various embodiments of the disc brake system and components, and methods for the use and assembly thereof, provide significant advantages over other disc brake systems and methods. For example, and without limitation, the interface between the brake pad(s) and carrier portions acting in tension reduces the likelihood of tapered pad wear, such that the brake pads wear more evenly and do not need to be replaced as frequently. In addition, the integral formation of the carrier portion and the mounting portion as a single piece torque plate unit improves the stability and strength of the torque plate, while simplifying the system, reducing the assembly time and eliminating various fasteners, which may be lost and/or improperly installed. The system also avoids a junction between the two components that may be susceptible to corrosion. The integral torque plate also provides a stable machining geometry for the pad supports and corresponding pad clearance, which minimizes the risk of pad kick. The improved one-piece torque plate also reduces or eliminates joint slip during dynamic loading of the torque plate.
The foregoing paragraphs have been provided by way of general introduction, and are not intended to limit the scope of the claims presented below. The various preferred embodiments, together with further advantages, will be best understood by reference to the following detailed description taken in conjunction with the accompanying drawings.
It should be understood that the term “plurality,” as used herein, means two or more. The term “longitudinal,” as used herein means of or relating to a length or lengthwise direction 2, or X direction, for example a direction running parallel to a brake pad. The term “lateral,” as used herein, means situated on, directed toward or running in a side-to-side direction 4, or Y direction, transverse to the longitudinal direction 2. The term “transverse” means non-parallel. The term “outboard” refers to a position or a direction facing outwardly away from a centralized location, for example a rotor 128, while the term “inboard” refers to a position or a direction facing inwardly relative to the rotor 128.
The term “coupled” means connected to or engaged with, whether directly or indirectly, for example with an intervening member, and does not require the engagement to be fixed or permanent, although it may be fixed or permanent. The terms “first,” “second,” and so on, as used herein are not meant to be assigned to a particular component so designated, but rather are simply referring to such components in the numerical order as addressed, meaning that a component designated as “first” may later be a “second” such component, depending on the order in which it is referred. It should also be understood that designation of “first” and “second” does not necessarily mean that the two components or values so designated are different, meaning for example a first direction may be the same as a second direction, with each simply being applicable to different components.
Referring to
The pad supports 302, 304, 306, 308 may be referred to as horns, in that then extend outwardly from the opening 11 of the mounting portion, for example in a Z-direction 5. It should be understood that the X direction is not necessarily horizontal, or the Z direction vertical, but rather that those directions are orthogonal and may rotate about the Y axis depending on the location of the disc brake system, which may be positioned at any orientation about the Y axis. The inboard leading and trailing pad supports 302, 304, or horns, are spaced apart in the longitudinal direction 2 and define an inboard pad receiving opening 310, while the outboard leading and trailing pad supports 306, 308 are spaced apart in the longitudinal direction 2 and define an outboard pad receiving opening 312. As shown in
An inboard brake pad 120 is disposed in the inboard pad receiving opening 310 and an outboard brake pad 122 is disposed in the outboard pad receiving opening 312. The inboard and outboard brake pads 120, 122 include a bearing surface 318, 320 facing toward the bearing surface 314, 316 respectively and the corresponding one of the inboard and/or outboard receiving openings 310, 312. The first and second bearing surfaces 314, 318 of the inboard pad support 302 and brake pad 120 and/or the first and second bearing surfaces 316, 320 of the outboard pad support 306 and brake pad 122, are configured to engage when the disc brake system is actuated such that at least a portion of the at least one inboard and/or outboard brake pads 120, 122, and in particular the leading ends thereof, is/are put in tension. It should be understood that both, or only one, of the inboard and outboard brake pads and pad support combinations may include bearing surfaces.
In one embodiment, the inboard leading and trailing pad supports 302, 304 are aligned with the mounting portion 9 as shown in
Referring to the embodiment of
In one embodiment, shown in
In the embodiment of
In the embodiment of
In various embodiments, either and/or both of the inboard and outboard leading pad supports 302, 306 may include a first bearing surface, and either and/or both of the inboard and outboard brake pads 120, 122 may include the second bearing surface engaging the first bearing surface. In other embodiments, each of the inboard leading pad support 302, the inboard trailing pad support 304, the outboard leading pad support 306, and the outboard trailing pad support 308 are configured with a slot, whether T-shaped, elbow shaped or opening outwardly along the Z axis, and wherein each of the inboard and outboard brake pads 120, 122 is configured with opposite ends having tabs disposed in corresponding ones of the slots.
The inboard and outboard brake pads 120, 122 each include a backing plate 330, 332 and a friction material 334, 336 supported by the backing plate. The bearing surfaces 318, 320, 342, tabs 378, 380, 406, 408 and end portions 354, 356 are formed on the backing plate 330, 332, which is made of a material suitable to absorb the tension and/or bending loads applied thereto, such as metal, including for example and without limitation a stamped steel or cast iron.
In operation, and referring to
As shown in
In essence, during braking, the friction on the brake pads 120, 122 applies a tension force to a leading end 410, 412 of at least one of the inboard and/or outboard brake pads in response to engaging the rotor 128 with the brake pads 120, 122. The tension force is absorbed with and by the carrier portion pad supports 302, 306 of the torque plate 8. At the same time, a compression force may be applied to the trailing end 414, 416 of the outboard brake pads in response to engaging the rotor surface with the brake pads 120, 122. The trailing end 414, 416 may be configured with tabs having an L-shape or hammer head shape, or may simply be a linear tab 480, 484 lacking any bearing surfaces extending in the Z direction and thereby being incapable of carrying any tension load during reverse direction braking as shown in
Referring to
Referring to
The caliper housing 32 defines a cavity 80. A lever 82 is disposed in the cavity and is supported by two eccentric bearings 84 disposed in the cavity. The lever 82 has a first portion 86, or arm, extending laterally into the cavity and a second portion 88 engaging a bridge 90, for example through a cylindrical bearing 92. The first portion 86 is engaged by an actuator 100, which may be mounted to the caliper housing 32 with fasteners 102. The bridge 90 is biased inwardly, away from the brake pads 120, 122 along a longitudinal axis 104 by a return spring 106.
The actuator 100 includes an air supply port 108 in fluid communication with a service brake chamber 110. As air is introduced into the chamber during application of the vehicle brakes, the air applies pressure in the chamber and expands the diaphragm 112 which in turn applies a force to and moves a pressure plate 114 and pushrod 116 in an axial direction. The pushrod 116 includes a pusher tip 118 that engages the lever cup creating a ball joint, and pushes the lever 82. The lever 82 thereafter rotates and pivots about the eccentric bearing 84 from an unactuated home position to an actuated position where the clamping load equates to the actuator input force minus internal friction losses. As the lever 82 pivots, the second portion 88 of the lever engages and moves the bridge 90 outwardly in the axial direction from a first position to a second position against the force of the return spring 106. The bridge 90 is coupled to and moves a pair of tubes and tappets 124, 126 in the longitudinal direction 2 so as to move an inner brake pad 120 in the longitudinal direction. The inner brake pad 120 engages the brake rotor 128. Further movement of the bridge 90 forces the caliper 30, sliding on the guide pins 16, 18, away from the rotor 128 in the longitudinal direction 2 from a non-braking position to a braking position. The sliding movement of the caliper 30 on the guide pins 16, 18 moves the outer brake pad 122 inwardly toward an opposite side of the rotor 128, thereby clamping the rotor 128 between the inner and outer brake pads 120, 122 and applying a braking force to the brake rotor 128 and attached wheel 130. The brake pads 120, 122 are coupled to the carrier and caliper with a pad retainer 121 and springs 123. Alternatively, in those embodiments with a capture system, as shown in
When the vehicle brakes are released, the air pressure in the service brake chamber 110 is exhausted and the return springs 117, 106 in the chamber and in the cavity acting on the bridge 90 return the air disc brake to a neutral, non-braked position. To maintain an appropriate running clearance gap between the rotor 128, 428 and the brake pads 120, 122 over time, the non-braked position may be mechanically adjusted by a mechanism in the caliper. The adjustment mechanism operates automatically whenever the brakes are activated, to compensate for rotor and brake pad wear and to keep the running clearance constant.
In operation, the method of actuating the air disc brake system includes applying a force (F1) to the lever 82 with the actuator 100, moving the bridge 90 in a first axial direction 150 with the lever 82 in response to the force (F1) being applied to the lever, moving an inner brake pad 120 operably coupled to the bridge 90 in the first axial direction 150, sliding a caliper 30 in a second axial direction 152 opposite the first axial direction on the guide pin 16, elastically deforming the sealing ring 52 disposed between the caliper 30 and the guide pin 16, and moving the outer brake pad 122 in the second axial direction 152 with the caliper 30. The method may further include releasing the force from the lever 82, biasing the bridge 90 in the second axial 152 direction with a spring 106, and biasing the caliper 30 in the first axial direction 150 with the sealing ring 52.
Although the present invention has been described with reference to preferred embodiments, those skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. As such, it is intended that the foregoing detailed description be regarded as illustrative rather than limiting and that it is the appended claims, including all equivalents thereof, which are intended to define the scope of the invention.
