Brake system and control method

Abstract

A brake system and control method that reduces maintenance time and associated costs in a sensor unit mounted on a brake pad assembly. [Solution] The brake system comprises a friction brake, a sensor unit 96, and a controller. The sensor unit is disposed on the brake pad assembly of the friction brake and comprises a first sensor and a second sensor 98 electrically connected to the first sensor.

Description

Technical Field

[0001] The present invention relates to a braking system and a control method.

Background Art

[0002] A disc brake assembly having a sensor assembly is disclosed in U.S. Patent No. 11,649,864.

Summary of the Invention

[0003] The present invention relates to a braking system. The braking system includes a friction brake, a sensor unit, and a controller. The friction brake includes a brake pad assembly. The brake pad assembly includes a backplate and a friction material. The backplate has a first side surface and a second side surface. The first side surface is disposed on the opposite side of the second side surface. The friction material extends from the first side surface. The friction material extends away from the second side surface. The sensor unit is disposed on the brake pad assembly. The sensor unit includes a first body, a first sensor, a second body, and a second sensor. The first body extends from the first side surface of the backplate. The first body is disposed close to the friction material. The first sensor is disposed inside the first body. The second body extends from the second side surface of the backplate. The second body is connected to the first body. The second sensor is disposed inside the second body. The first sensor is electrically connected to the second sensor. The controller is electrically connected to the second sensor by a data bus.

[0004] The first sensor may be encapsulated within the first body. The first sensor may not be disposed within the second body. The second sensor may be encapsulated within the second body. The second sensor may not be disposed within the first body.

[0005] The backplate may extend from the first body to the second body. The backplate may separate the second body from the friction material. The second body may not be in contact with the friction material.

[0006] The sensor unit may be fixed to a backplate. The first sensor may be a thermistor. The thermistor is configured to provide a signal indicating the temperature of the first body to the second sensor.

[0007] A second sensor may be configured to receive a signal from the first sensor. The second sensor may be configured to generate an output signal. The output signal may include a serial number and a temperature code. The serial number may be the serial number of the second sensor. The temperature code may be based on the signal from the first sensor.

[0008] The controller may be configured to receive output signals from a second sensor via a data bus. The controller may be configured to determine the location of the sensor unit based on its serial number. The controller may be configured to determine the temperature value based on its temperature code.

[0009] The thermistor can indicate the wear condition of the friction material in the brake pad assembly. If the signal shows a resistance below a first resistance boundary value, the signal may indicate a wear condition. If the signal shows a resistance above a second resistance boundary value, the signal may also indicate a wear condition.

[0010] The present invention also relates to a method for controlling a brake system. The method includes providing a signal from a first sensor of a sensor unit to a second sensor of the sensor unit. The sensor unit is disposed on a brake pad assembly of a friction brake. The signal indicates the temperature of the brake pad assembly. The method includes generating an output signal from the second sensor that includes the serial number and temperature code of the second sensor. The temperature code is based on a signal from a thermistor. The method includes communicating the output signal to a controller. The method includes the controller locating the sensor unit based on the serial number. The method includes the controller locating the temperature of the sensor unit based on the temperature code. The method includes the controller communicating the location and temperature of the sensor unit to a communication device.

[0011] Communicating the output signal may further include communicating the output signal to a controller via a data bus. Communicating the position and temperature of the sensor unit to a communication device may further include the communication device providing notification when the temperature exceeds a predetermined temperature value.

[0012] The method may further include mounting a sensor unit to a brake pad assembly so that, prior to the first sensor providing a signal, the first body of the sensor unit enclosing the first sensor extends from a first side of the back plate of the brake pad assembly disposed adjacent to the friction material of the brake pad assembly, and the second body of the sensor unit enclosing the first sensor extends from a second side of the back plate disposed on the opposite side of the first side.

[0013] The present invention relates to a brake system. The brake system comprises a first friction brake, a second friction brake, a controller, and a wire harness. The first friction brake and the second friction brake each comprise a brake pad assembly and a sensor unit. The brake pad assembly comprises a back plate and a friction material. The back plate has a first side and a second side. The first side is located opposite the second side. The friction material extends from the first side. The friction material extends away from the second side. The sensor unit is located on the back plate. The sensor unit comprises a first body, a first sensor, a second body, and a second sensor. The first body extends from the first side of the back plate. The first body is located close to the friction material. The first sensor is located inside the first body. The second body extends from the second side of the backplate. The second body is connected to the first body. The second sensor is housed inside the second body. The second sensor is electrically connected to the first sensor. The wire harness comprises a first resistor, a second resistor, a first conductor, a second conductor, and a data bus. The first resistor is electrically connected to the sensor unit of the first friction brake by the first conductor. The second resistor is electrically connected to the sensor unit of the second friction brake by the second conductor. The first and second resistors have different electrical resistances. The data bus electrically connects the controller to the sensor unit of the first friction brake. The data bus electrically connects the controller to the sensor unit of the second friction brake.

[0014] A second sensor of the first friction brake sensor unit may be configured to measure the resistance value of a first resistor. The second sensor of the first friction brake sensor unit may be configured to generate a first position address based on the resistance value of the first resistor. The second sensor of the first friction brake sensor unit may be configured to provide the first position address to a controller. The first position address may indicate the position of the first friction brake sensor unit.

[0015] The second sensor of the second friction brake sensor unit may be configured to measure the resistance value of a second resistor. The second sensor of the second friction brake sensor unit may be configured to generate a second position address based on the resistance value of the second resistor. The second sensor of the second friction brake sensor unit may be configured to provide the second position address to the controller. The second position address may indicate the position of the second friction brake sensor unit.

[0016] The first resistor may be housed in the first connector plug of the wire harness. The first connector plug may be connected to the connector plug of the sensor unit of the first friction brake. The second resistor may be housed in the second connector plug of the wire harness. The second connector plug may be connected to the connector plug of the sensor unit of the second friction brake. [Brief explanation of the drawing]

[0017] [Figure 1] Let's illustrate this with an example of a vehicle equipped with a braking system. [Figure 2] This is a perspective view of an example of a friction brake. [Figure 3] This is a cross-sectional view of a portion of the friction brake along the cutting line 3-3. [Figure 4] This is an enlarged view of a portion of Figure 3, showing an example of friction material and sensor unit. [Figure 5] This is an enlarged view showing an example of worn friction material and a sensor unit. [Figure 6] This is a schematic diagram showing multiple sensor units connected to a controller via a wire harness equipped with a data bus. [Figure 7] This is an enlarged sub-diagram of an example of a wire harness and associated electrical connector. [Figure 8] This table shows examples of resistance values ​​and associated output bits. [Modes for carrying out the invention]

[0018] Where necessary, detailed embodiments of the present invention are disclosed herein; however, it should be understood that the disclosed embodiments are merely illustrative examples of the present invention, which can be embodied in various and alternative forms. The figures are not necessarily to scale, and some features may be exaggerated or minimized to illustrate the details of certain components. Therefore, the specific structural and functional details disclosed herein should not be limited, but rather construed as representative examples to teach those skilled in the art how to use the present invention in various ways.

[0019] Furthermore, while terms such as "first," "second," etc., are used herein in some cases to describe various elements, it will be understood that these elements should not be limited by these terms. These terms are used solely to distinguish one element from another. For example, without departing from the scope of various embodiments, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. Both the first and second elements are elements, but they are not the same element.

[0020] The terms used in the description of the various embodiments described are for the purpose of describing particular embodiments only and are not intended to be limiting. When used in the description of the various embodiments described and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. Also, the term "and / or" as used herein refers to any and all possible combinations of one or more of the associated listed items and is to be understood to be inclusive. The terms "includes", "including", "comprises", and / or "comprising", as used herein, specify the presence of the stated features, elements, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, elements, steps, operations, elements, components, and / or groups thereof.

[0021] Referring to FIG. 1, a schematic example of a vehicle 10 is shown. The vehicle 10 can be of any suitable type such as a truck, bus, farming machine, mining machine, military transport or weapon vehicle, cargo loading machine for land, air, or sea vessels, trailer for cargo transport, and the like. The vehicle 10 includes one or more axle assemblies 20 and a brake system 22.

[0022] In some configurations, the axle assembly 20 is configured to support one or more wheels 30. For example, the wheel 30 can be fastened to a wheel hub 32 that can be rotatably disposed on the axle assembly 20. The tire 34 is disposed on the wheel 30 and is rotatable together with the wheel 30. The axle assembly 20 can also support the brake assembly of the brake system 22. The axle assembly 20 can be provided in an operable configuration or a non-operable configuration. In an operable configuration, the axle assembly 20 can be an operable structural component such as a steering knuckle. The axle assembly 20 can be provided in a drive axle configuration or a non-drive axle configuration. In a drive axle configuration, the axle assembly 20 is configured to provide torque to the associated vehicle wheel from a torque source such as an electric motor or an internal combustion engine to propel the vehicle 10. In a non-drive axle configuration, torque is not provided from the torque source to the associated vehicle wheel to propel the vehicle 10.

[0023] The brake system 22 is configured to decelerate or inhibit the rotation of the associated wheel hub 32, and thus to decelerate or inhibit the rotation of the wheel 30 fastened to the wheel hub 32. In some configurations, the brake system 22 includes a set of friction brakes 40, a set of sensor units 42, and a controller 44. In FIG. 1, the individual sensor units 42 are distinguished by different letters such as A, B, C, and D after the number 42.

[0024] The friction brake 40, which can also be called a base brake, is configured to decelerate the rotation of the wheel hub 32. The friction brake 40 can be disposed in proximity to the wheel hub 32 and attached to the axle assembly 20 so that the friction brake 40 does not rotate with the wheel hub 32.

[0025] The vehicle 10 may be provided with multiple friction brakes 40, which may be referred to as a set of friction brakes 40. In the shown configuration, four friction brakes 40 are illustrated for simplicity, and it should be noted that the friction brakes 40 may be provided to brake the wheel and wheel hub shown near the top of Figure 1.

[0026] The friction brake 40 may have any preferred configuration. For example, the friction brake 40 may be configured as a disc brake or a drum brake. Referring to Figure 2, an example of a friction brake 40 configured as a disc brake is shown. The friction brake 40 may include, or be associated with, a brake friction member 50, best shown in Figure 3, and a brake pad assembly 52. ​​In some configurations, such as when the friction brake 40 is configured as a disc brake, the friction brake 40 may include a brake carrier 54, a brake caliper 56, a retainer strap 58, a pad spring 60, or both.

[0027] Referring to Figure 3, the brake friction member 50 is rotatable with the wheel hub 32. For example, when braking is not required, the brake friction member 50 may be fixed to the wheel hub 32 and may rotate with the wheel hub 32 relative to the brake pad assembly 52. ​​In Figure 3, for clarity, the brake friction member 50 is shown conceptually. In a disc brake configuration, the brake friction member 50 is configured as a brake rotor, also known as a brake disc. In a drum brake configuration, the brake friction member 50 is configured as a brake drum.

[0028] Referring to Figures 2 and 3, the brake pad assembly 52 is configured to engage with the brake friction member 50 when braking is requested or commanded, and to exert a frictional force on the brake friction member 50 to slow down or decelerate the rotation of the wheel hub 32 and associated wheel 30.

[0029] In a disc brake configuration, inner and outer brake pad assemblies 52 are positioned on both sides of a brake friction member 50 and are configured to engage with both sides of the brake friction member 50 to slow or decelerate the rotation of the brake friction member 50, the wheel hub 32, and the associated wheel 30 around the axis of rotation. In such a configuration, the brake pad assemblies 52 may be received in a brake caliper 56, which is movably mounted on a brake carrier 54. The brake carrier 54 may be fixed in a stationary manner to the axle assembly 20. The brake caliper 56 facilitates the positioning of the brake pad assemblies 52 relative to the brake friction member 50. For example, the brake caliper 56 may be configured to position the brake pad assemblies 52 engaged with both sides of the brake friction member 50 to facilitate braking of the brake friction member 50, and to facilitate the retraction of the brake pad assemblies 52 to disengage the brake friction member 50.

[0030] In a drum brake configuration, one or more brake pad assemblies, also known as brake shoes, are configured to engage with the inner surface of a brake drum facing the axis of rotation of the wheel hub. For example, a camshaft may rotate in a first rotational direction to actuate a brake torque by engaging the brake pad assembly with the inner surface of the brake drum, and the camshaft may rotate in a second rotational direction to retract the brake pad assembly away from the inner surface of the brake drum.

[0031] The brake pad assembly 52 is configured to engage with the brake friction member 50 and exert force during braking. In some configurations, the brake pad assembly 52 comprises a back plate 70 and a friction material 72.

[0032] The backplate 70, also called a table, is a structural component of the brake pad assembly 52. ​​The backplate 70 may be constructed as a plate and may be made of any suitable material such as metal or a metal alloy. In a disc brake configuration, the backplate 70 may generally be flat, and in a drum brake configuration, it may be curved along an arc that follows the inward curvature of the brake drum. As best shown in Figure 3, the backplate 70 comprises a first side surface 74 and a second side surface 76.

[0033] The first side surface 74 faces the brake friction member 50. For example, in a disc brake configuration, the first side surface 74 may face the brake rotor, and in a drum brake configuration, it may face the inside of the brake drum.

[0034] The second side surface 76 is located on the opposite side of the first side surface 74. Therefore, the second side surface 76 faces in the opposite direction from the brake friction member 50.

[0035] The friction material 72 is configured to contact the brake friction member 50 during braking. The friction material 72, which may also be called the brake lining, is disposed on and extends from the first side surface 74 of the backplate 70. The friction material 72 extends away from the second side surface 76 toward the brake friction member 50. The friction material 72 is fixed to the backplate 70 so that the friction material 72 and the backplate 70 move together when the brake pad assembly 52 is actuated.

[0036] Referring to Figures 2 and 3, the friction material 72 may include a recess 78. The recess 78 may extend from the back plate 70 or a first side surface 74 of the back plate 70 to a side surface or surface of the friction material 72, the side surface or surface facing the brake friction member 50 and being able to engage with the brake friction member 50.

[0037] The brake pad assembly 52 is movable between a retracted position and a protruding position. Figure 3 shows the brake pad assembly 52 in the retracted position. When the brake pad assembly 52 and its friction material 72 are in the retracted position, they are separated from the brake friction member 50 and do not engage with the brake friction member 50. Thus, in the retracted position, a clearance gap 80 is provided between the friction material 72 and the brake friction member 50. In the protruding position, the brake pad assembly 52 is actuated toward the brake friction member 50, thereby causing the friction material 72 to contact the brake friction member 50, and the clearance gap 80 no longer exists.

[0038] Referring to Figures 2 and 3, the retainer strap 58 may be removablely mounted on the brake caliper 56. Once installed, the retainer strap 58 may be fixed to the brake caliper 56, thereby allowing the brake caliper 56 and the retainer strap 58 to move together relative to the brake carrier 54. The retainer strap 58 may extend across the brake pad assembly 52 to help hold the brake pad assembly 52 in place on the brake carrier 54. Once the retainer strap 58 is installed and fixed to the brake caliper 56, the retainer strap 58 may engage with or contact the brake pad assembly 52, or, if provided, with the pad spring 60.

[0039] Optionally, a pad spring 60 is disposed between the retainer strap 58 and the sensor unit 42. The pad spring 60 may be disposed on the back plate 70 and may engage with or contact the retainer strap 58 and the sensor unit 42, thereby exerting a biasing force that biases the back plate 70 away from the retainer strap 58, sandwiching the sensor unit 42 between the pad spring 60 and the back plate 70, and preventing the sensor unit 42 from detaching from the back plate 70. In some configurations, such as when the pad spring 60 is omitted, the retainer strap 58 engages with the sensor unit 42. It is also conceivable that the sensor unit 24 may not contact or engage with the retainer strap 58. For example, the sensor unit 24 may have sufficient gripping strength to fix itself to the back plate 70.

[0040] Referring primarily to Figures 2 and 3, the friction brake 40 is provided with a sensor unit 42. The sensor unit 42 is disposed on the brake pad assembly 52. ​​The sensor unit 42 may be fixed to a back plate 70. For example, the sensor unit 42 may be fixed to the back plate 70, thereby allowing the sensor unit 42 to move together with the brake pad assembly 52. ​​For example, the sensor unit 42 may straddle the back plate 70, which may help to hold the sensor unit 42 on the back plate 70 when the brake pad assembly 52 is actuated. In some configurations, the sensor unit 42 is received in a recess 78 of the friction material 72. For example, the sensor unit 42 may be partially received in a recess 78 of the friction material 72, which may allow the sensor unit 42 to contact or engage with the friction material 72, which may allow the friction material 72 to restrain the movement of the sensor unit 42, and which may help to hold the sensor unit 42 in the recess 78. In some configurations, as best shown in Figure 3, the sensor unit 42 comprises a first body 90, a second body 92, a bridge 94, and one or more sensors such as a first sensor 96 and a second sensor 98.

[0041] Referring primarily to Figure 3, the first body 90 extends from the first side surface 74 of the backplate 70. For example, the first body 90 may contact a portion of the first side surface 74 of the backplate 70 where the friction material 72 is not present, and extend along it into a recess 78 of the friction material 72. The first body 90 is disposed in close proximity to or adjacent to the friction material 72. In some configurations, the first body 90 may engage with or contact the friction material 72 in the recess 78 to help restrain the movement of the first body 90 relative to the friction material 72. The first body 90 may project from the first side surface 74 toward the brake friction member 50 or toward the side surface of the friction material 72, such that the friction material 72 faces and contacts the brake friction member 50. The first body 90 may have a thickness extending away from the second body 92 (for example, from left to right in the shown viewpoint), and this thickness may be less than or equal to the thickness of the friction material 72 when the friction material 72 is unworn. Optionally, the first body 90 may have a thickness greater than that of the second body 92. In some configurations, the first body 90 includes an outer 100 and an inner 102. The outer 100 may face away from the backplate 70. The inner 102 may be located on the opposite side of the outer 100. The inner 102 may face toward the backplate 70 and may contact or engage with the backplate 70.

[0042] Referring mainly to Figure 3, the second body 92 extends from the second side 76 of the back plate 70. For example, the second body 92 may extend in a direction away from the second side 76 and away from the first side 74. The second body 92 may protrude from the second side 76 of the back plate 70 and may extend away from the brake friction member 50 and the friction material 72. The back plate 70 may extend from the first body 90 to the second body 92, thereby separating the first body 90 from the second body 92. Furthermore, the back plate 70 may separate the second body 92 from the friction material 72, thereby preventing the second body 92 from contacting the friction material 72. In some configurations, the second body 92 is separated from the first body 90. The second body 92 may have the same width as the first body 90 or a different width.

[0043] The bridge 94 interconnects the first body 90 and the second body 92. For example, the bridge 94 may extend from the first body 90 to the second body 92, or it may extend across the backplate 70, such as across the top side of the backplate 70. In some configurations, the bridge 94 engages with the pad spring 60 and the backplate 70 or retainer strap 58. The bridge 94 may be formed integrally with the first body 90 and the second body 92. For example, the first body 90, the second body 92, and the bridge 94 may be integrally formed from a polymer material such as silicone, which can withstand the temperatures associated with braking while maintaining sufficient structural integrity (e.g., without melting). Furthermore, such a material may limit heat absorption and may help provide some degree of thermal insulation that can help protect the internal components of the sensor unit 42.

[0044] The following discussion will examine the sensors in which the sensor unit 42 may be provided, with reference to Figure 3. In general, one or more sensors may be enclosed within the sensor unit 42. The sensors may be configured to provide signals indicating one or more attributes associated with the friction brake 40. For example, the sensors may detect or provide signals indicating wear of the friction material 72, the temperature of the brake pad assembly 52, etc. The sensors will be discussed below with reference to a first sensor 96 and a second sensor 98, which are of different types or have different configurations.

[0045] The first sensor 96 is disposed inside the first body 90 of the sensor unit 42. The first sensor 96 may be enclosed within the first body 90. For example, if the first body 90 is not worn, the first sensor 96 may be positioned between the outer 100 and inner 102 of the first body 90. The first sensor 96 may not be disposed inside the second body 92, inside the bridge 94, or both.

[0046] The first sensor 96 may have any preferred configuration. In some configurations, the first sensor 96 is configured to provide a signal indicating wear of the friction material 72. For example, the first sensor 96 may comprise one or more resistors. When the friction material 72 engages with the brake friction member 50, the friction material 72 wears down. As a result, the thickness of the friction material 72 decreases. After sufficient wear has occurred, the side of the friction material 72 facing the brake friction member 50 may become substantially aligned with the outside 100 of the first body 90. As a result, additional braking application may result in engagement between the friction material 72 and the first body 90 and the brake friction member 50, and may result in wear of the friction material 72 and the first body 90. After sufficient wear has occurred, the first sensor 96 or a part thereof may become exposed, separated, or both. An example of this is shown in Figure 5. In this state, the signal generated by the first sensor 96 may be associated with opening or closing an electrical circuit. For example, the electrical circuit associated with the first sensor 96 may disconnect or otherwise interrupt an electrical circuit that is normally connected, resulting in a change in one or more electrical properties, such as a decrease in current or no current, or an increase in resistance. Alternatively, when the conductor of the first sensor 96 contacts the brake friction member 50, the first sensor 96, which normally has an electrical circuit that is not connected or is open, is closed, thereby allowing current to be conducted through the brake friction member 50.

[0047] In some configurations, the first sensor 96 is configured to provide a signal indicating the temperature of the first body 90. For example, the first sensor 96 may be a thermal sensor such as a thermistor or thermocouple. In the case of a thermistor, the resistance of the thermistor changes with temperature. The thermistor may be any preferred type, such as a negative temperature coefficient thermistor or a positive temperature coefficient thermistor. The resistance of a negative temperature coefficient thermistor decreases as the temperature rises. The resistance of a positive temperature coefficient thermistor increases as its temperature rises. Since the temperature generated in the first body 90 during braking may exceed the operating temperature of the microprocessor, the first sensor 96 may not include a controller such as a microprocessor. The first sensor 96 may provide an analog signal or an analog output.

[0048] The second sensor 98 is disposed inside the second body 92. The second sensor 98 is electrically connected to the first sensor 96, for example, by a conductor such as a wire. The first sensor 96 may be configured to provide a signal to the second sensor 98. The second sensor 98 may be enclosed within the second body 92. For example, the second sensor 98 may be positioned behind the backplate 70 and away from the friction material 72. As a result, the second sensor 98 is positioned further away from the brake friction member 50 and further away from the location where friction occurs and heat is generated during braking. Furthermore, the backplate 70 may help shield the second sensor 98 from the higher temperatures in which the first sensor 96 is located. Note that the second sensor 98 may be positioned further down from the indicated position so that the entirety of the second sensor 98 is positioned behind the backplate 70 and below the bridge 94. The second sensor 98 may not be located within the first main body 90, within the bridge 94, or both.

[0049] The second sensor 98 has a different configuration from the first sensor 96. In some configurations, the second sensor 98 includes a microprocessor. For example, the second sensor 98 may be configured as a digital temperature sensor capable of outputting a digital signal. An example of a digital temperature sensor is the MAX31825 digital temperature sensor from Maxim Integrated.

[0050] In some configurations, the first sensor 96 is electrically connected to the second sensor 98, thereby supplying the signal from the first sensor 96 to the second sensor 98. The second sensor 98 may provide an output or output signal to the controller 44 based on the signal from the first sensor 96.

[0051] Referring to Figures 1 and 6, multiple sensor units 42 may be provided. As previously discussed, in these figures, the sensor units are distinguished by the letters A, B, C, and D. Each friction brake 40 is provided with a sensor unit 42. The sensor units 42 may be electrically connected to a controller 44 via a wire harness 110. As best shown in Figure 7, the wire harness 110 may include data lines or a data bus 112. Each sensor unit 42 may communicate with the controller 44 via the data bus 112. Using a data bus rather than hard-wiring each sensor unit 42 to the controller 44 by one or more dedicated wires allows multiple sensor units 42 to communicate with the controller 44, thereby reducing the cost and complexity of the wire harness 110. The controller 44 is electrically connected to a second sensor 98 via the data bus 112.

[0052] The controller 44 may include various microprocessors, integrated circuits, memory devices (e.g., FLASH, random access memory (RAM), read-only memory (ROM), electrically programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or other suitable modifications), and software that works together to perform the operations disclosed herein. In addition, the controller 44 utilizes one or more microprocessors to execute a computer program embodied in a non-temporary computer-readable medium, programmed to perform any number of the functions disclosed herein. Furthermore, the controller 44 provided herein may include a housing, as well as various numbers of microprocessors, integrated circuits, and memory devices (e.g., FLASH, random access memory (RAM), read-only memory (ROM), electrically programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM)) located within the housing. Each disclosed controller also includes hardware-based inputs and outputs for receiving data from and transmitting data to other hardware-based devices considered herein.

[0053] The controller 44 or control system may be configured to monitor and / or control the operation of the brake system 22. The controller 44 may include one or more control modules or controllers 44 that are provided to monitor and control various components. For simplicity, Figures 1 and 6 show a single controller 44.

[0054] Referring to Figure 1, in some configurations, the controller 44 is electrically connected to and communicates with a communication device 120. The communication device 120 may receive output signals from the controller 44 or provide input signals to the controller 44 or a combination thereof. For example, the communication device 120 may be provided to receive input from a driver or vehicle operator and optionally provide information to the driver. The communication device 120 may be any preferred one or more types such as switches, buttons, sensors, displays, touchscreens, etc., and the communication device 120 may facilitate communication with the driver by providing visual notifications, audible notifications, tactile notifications, or a combination thereof.

[0055] The controller 44 communicates with each sensor unit 42 via the data bus 112. In this configuration, it is useful to uniquely identify each sensor unit 42, which allows the controller 44 to determine the source of a signal or communication. Uniquely identifying each sensor unit 42 makes it possible to map the location of the sensor unit 42 on the vehicle 10, which allows a technician or vehicle operator to easily determine the location of the sensor unit 42 associated with a notification or warning from the controller 44. Such notifications or warnings may be communicated via the communication device 120.

[0056] Referring to Figures 6 and 7, in some configurations, the second sensor 98 and the wire harness 110 work together to uniquely identify the sensor unit 42. Figure 6 is a schematic diagram showing four sensor units 42 connected to the controller 44 by the wire harness 110. The sensor units 42 are designated 42A, 42B, 42C, and 42D. The wire harness 110 consists of electrical hardware or circuitry that enables each sensor unit 42 to be uniquely identified. Connector plug assemblies are used to electrically connect each sensor unit 42 to the corresponding branch or pigtail of the wire harness 110. The connector plugs may generally be referred to by reference number 130, more specifically, as connector plug assemblies 130A, 130B, 130C, and 130D, as indicated by the accompanying letters. As best illustrated in Figure 7, each connector plug assembly comprises a wire harness connector plug, which may be referred to as a first connector plug 132, and a corresponding sensor unit connector plug, which may be referred to as a second connector plug 134. Each connector plug assembly 130A, 130B, 130C, and 130D may comprise the first connector plug 132 and the second connector plug 134. For simplicity, only two connector plug assemblies 130A and 130B are illustrated in Figure 7.

[0057] Each first connector plug 132 is configured to mate with a second connector plug 134. The first connector plugs 132 and the second connector plugs 134 may have any preferred configuration. In the shown configuration, the first connector plug 132 is represented in a female configuration, while the second connector plug 134 is represented in a male configuration; however, the configuration may be reversed.

[0058] In some configurations, each first connector plug 132 is equipped with a resistor. For convenience of reference, the resistor provided in the first connector plug 132 of connector plug assembly 130A is referred to as the first resistor 136A. The resistor in the first connector plug 132 of connector plug assembly 130B is referred to as the second resistor 136B. In some configurations, the wire harness 110 has associated wires that ground each resistor or associated resistor.

[0059] The first resistor 136A is located within the first connector plug 132 of the connector plug assembly 130A. The first resistor 136A is electrically connected to the second sensor 98 of the sensor unit 42A by a first conductor 138A, such as an electrical conductor like a wire. The second sensor 98 may be configured to measure the resistance or resistance value of the first resistor 136A, generate a first position address based on the resistance value of the first resistor 136A, and provide the first position address to the controller 44 via the data bus 112. The first position address may indicate the position of the associated sensor unit 42A. For example, the controller or microprocessor of the second sensor 98 of the sensor unit 42A, or a controller or microprocessor provided on the second sensor 98 of the sensor unit 42A, may generate the first position address, which is a digital output or bit sequence based on the resistance value of the first resistor 136A. Multiple resistance values ​​or resistance ranges can be stored in memory, such as in a lookup table. The corresponding digital output can be selected from the lookup table by determining the output or bit sequence associated with the resistance value or resistance range (for example, a bit sequence of 0001 for the resistance of a first resistor such as 20Ω).

[0060] The second resistor 136B is located within the first connector plug 132 of the connector plug assembly 130B. The second resistor 136B is electrically connected to the second sensor 98 of the sensor unit 42B by a second conductor 138B, such as an electrical conductor like a wire. The second sensor 98 may be configured to measure the resistance or resistance value of the second resistor 136B, generate a second position address based on the resistance value of the second resistor 136B, and provide the second position address to the controller 44 via the data bus 112. For example, the controller or microprocessor of the second sensor 98 of the sensor unit 42B, or a controller or microprocessor provided on the second sensor 98 of the sensor unit 42B, may generate a second position address different from the first position address, which is a digital output or bit sequence based on the resistance value of the second resistor 136B. The second position address may indicate the location of the associated sensor unit 42B. The corresponding digital output can be selected from a lookup table by determining the output or bit sequence associated with the resistance value or resistance range (for example, a bit sequence of 0010 for the resistance of a second resistor such as 30Ω).

[0061] Therefore, the first resistor 136A and the second resistor 136B have different electrical resistances. Similarly, the resistors associated with the remaining connector plugs may also have corresponding resistors that have different or unique resistances compared to the resistors of the other connector plugs. The bit sequence can be transmitted to the controller 44 via the data bus 112. The controller 44 can then decode the bit sequence and associate it with a specific sensor unit. For example, different bit sequences may be associated with different sensor units or friction brake positions and stored in the memory of the controller 44. The controller 44 can match the bit sequence with the associated position stored in memory. As an example, the controller 44 may be programmed with position information or different position indicators for each position address. For example, sensor unit 42A may be mapped to or correspond to a first position address (e.g., 0001), sensor unit 42B may be mapped to or correspond to a second position address (e.g., 0010), and so on. Bit sequences can be transmitted to the controller 44 in a specific location or communication sequence to facilitate the identification of location-related bit sequences.

[0062] Providing resistors with different electrical resistances along with the wire harness 110 allows for the standardization of the sensor unit and the second connector plug 134, which facilitates assembly and replacement. Providing resistors with the first connector plug allows for the easy replacement of a defective or faulty resistor without replacing the entire wire harness, which reduces maintenance time and associated costs. Providing them differently at known locations allows for easy mapping of the resistances.

[0063] As another example, it may be desirable for the data bus to provide digital signals rather than analog signals. It may also be desirable to provide a solid-state sensor, an analog sensor, or a sensor without a microprocessor as the first sensor 96 to better withstand environmental conditions (e.g., temperature, friction material wear, wear of the first body), to provide more accurate temperature sensing, to reduce the cost of the first sensor 96 (e.g., by not including a microprocessor), or a combination of these. For example, the first sensor 96 may be configured as a thermistor that provides a temperature signal to the second sensor 98 rather than bypassing it. The resistance of the thermistor changes with temperature. The second sensor 98 may receive a signal from the thermistor and generate an output signal based on the signal from the thermistor. In some configurations, the output signal generated by the second sensor 98 includes a serial number and a temperature code.

[0064] The serial number may be the serial number or serial code of the second sensor 98. For example, each second sensor 98 may be provided with a unique serial number, such as a multi-bit serial number or 64-bit serial number. The serial number may be mapped by the controller 44 to a specific friction brake position or sensor unit position. For example, a sensor unit may be connected to a data bus and communicate its serial number to the controller 44. The controller 44 may receive a serial number and a pair of serial numbers for a given vehicle position. For example, the sensor units may be connected to the data bus 112 in a predetermined pattern, such as starting with the forward driver-side friction brake and then proceeding around the vehicle 10 in a clockwise or counterclockwise pattern, so that each sensor unit is sequentially mapped by each serial number associated with the corresponding position in the connection sequence. As another example, all sensor units may be connected to the data bus 112, and one sensor unit may be disconnected at a time in a predetermined pattern. Thus, the controller 44 may first receive the serial number from each sensor unit, and then the sensor units may be disconnected from the data bus one at a time in a predetermined position pattern. For example, the sensor unit for the front driver-side friction brake may be the first to be disconnected. As a result of the disconnection, the serial number associated with that sensor unit is no longer communicated to the controller 44. Thus, the controller 44 may pair the sensor unit with the missing serial number with the front driver-side friction brake position. The sensor unit may then be reconnected to the data bus 112, and the next sensor unit in the sequence may be disconnected. The disconnect / reconnect sequence may be repeated until all sensor units are mapped by the controller 44. Thus, the controller 44 can identify individual sensor units based on the serial number and corresponding position of the second sensor 98.

[0065] The temperature code is based on the signal from the first sensor 96. The second sensor 98 may be configured to receive, detect, or measure the resistance or resistance value of the first sensor 96. Rather than generating a position address based on the resistance value, the second sensor 98 may generate a sequence or bit sequence associated with the resistance or resistance value provided by the first sensor 96, such as the resistance of a thermistor. Multiple resistance values ​​or resistance ranges may be stored in memory, such as in a lookup table. The corresponding digital output may be selected from the lookup table by determining the output or bit sequence associated with the resistance value or resistance range. An example of such a table is shown in Figure 8, but note that only some resistance values ​​and their corresponding outputs or bit sequences are shown, as indicated by the dashed line after the row of 8Ω resistors. Using a thermistor as an example, when the resistance of the thermistor changes, the signal or bit sequence generated by the second sensor 98 changes accordingly. The second sensor 98 then transmits its serial number and bit sequence or temperature code to the controller 44.

[0066] The controller 44 may then process or decode the signal by identifying the sensor unit using the serial number and by identifying the temperature associated with the temperature code using the temperature code. For example, each temperature code may correspond to a temperature value or temperature range. The temperature values ​​or temperature ranges may be stored in the controller 44's memory, such as a lookup table, and the temperature values ​​or temperature ranges may be selected from the lookup table based on the temperature code. If the temperature value or temperature range exceeds a predetermined temperature limit, the controller 44 may communicate the temperature or temperature range to the communication device 120 or issue a notification via the communication device 120. The predetermined temperature limit may be a temperature exceeding the expected operating temperature of the friction brake. In a non-limiting example, the temperature value may be 600°F (316°C).

[0067] Generating a temperature code by the second sensor 98 allows the temperature signal to be provided in a digital format before being sent to the wire harness, which enables the use of a common data bus for multiple sensor units. Generating a temperature code by the second sensor 98 also allows the second unit of the second sensor 98 and its associated microprocessor to be positioned within a lower temperature range of the sensor unit 42, which may enable the use of a lower-cost microprocessor or second sensor 98. In some configurations, the temperature code may be generated in a manner similar to how a position address is generated, however, the temperature code indicates temperature, and temperature is a variable rather than a constant or steady-state position.

[0068] In some configurations, the signal from the first sensor 96 may indicate the wear condition of the friction material 72 of the brake pad assembly 52. ​​For example, the first sensor 96, configured as a thermistor, may provide resistance or resistance values ​​within its operating range. In one non-limiting example shown in Figure 8, the thermistor may have an operating range of 9 to 920 kΩ. In this example, 9 kΩ may be specified as the first resistance boundary value, and 920 kΩ may be specified as the second resistance boundary value. The first and second resistance boundary values ​​may be selected such that, when the first sensor 96 is functioning properly, the temperature signal provided by the first sensor 96 is expected to be between the first and second resistance boundary values ​​over the operating temperature range of the friction brake.

[0069] If the signal from the first sensor 96 is below a first resistance boundary value, above a second resistance boundary value, or both, the signal from the first sensor 96 may indicate the wear state of the friction material 72.

[0070] In some configurations, a signal exceeding a second resistance threshold may indicate an open circuit caused by wear of the first body 90 to the point of damaging the thermistor, resulting in an open-circuit condition as shown in Figure 5. The thermistor may be positioned such that an open-circuit condition occurs when the friction material 72 is worn to a predetermined depth or by a predetermined amount. Thus, the signal from the first sensor 96 may indicate the friction material worn down to the location of the thermistor. The controller 44 may compare the temperature associated with the signal from the first sensor 96 with the second resistance threshold. The controller 44 may generate a warning or notification if the temperature associated with the signal from the first sensor 96 exceeds the second resistance threshold. The warning or notification may be output to a communication device 120, which may locate the associated sensor unit 42 or prompt the driver to inspect or potentially replace the associated brake pad assembly 52.

[0071] As another example, a signal below the first resistance boundary value may also indicate the wear condition of the friction material 72. For example, if the first sensor is exposed and engages with the brake friction member 50, the electrical circuit may be closed, thereby providing a resistance that is lower than expected during normal thermistor operation and therefore lower than the first resistance boundary value. The controller 44 may compare the temperature associated with the signal from the first sensor 96 with the first resistance boundary value and generate a warning or notification if the temperature associated with the signal from the first sensor 96 is below the first resistance boundary value.

[0072] While exemplary embodiments are described above, these embodiments are not intended to describe all possible forms of the invention. Rather, the terms used herein are descriptive rather than limiting, and it should be understood that various modifications can be made without departing from the spirit and scope of the invention. In addition, features of various implementing embodiments can be combined to form further embodiments of the invention.

Claims

1. It is a brake system, A friction brake comprising a brake pad assembly, wherein the brake pad assembly is A back plate having a first side and a second side disposed on the opposite side of the second side, A friction brake comprising a friction material extending from the first side and extending away from the second side, A sensor unit disposed on the brake pad assembly, wherein the sensor unit is A first body extending from the first side surface of the back plate and disposed in close proximity to the friction material, The first sensor is disposed inside the first main body, A second body extending from the second side surface of the back plate and connected to the first body, A sensor unit comprising: a second sensor disposed inside the second main body and electrically connected to the first sensor; A brake system comprising a controller electrically connected to the second sensor by a data bus.

2. The brake system according to claim 1, wherein the first sensor is enclosed within the first main body and is not disposed within the second main body.

3. The brake system according to claim 1, wherein the second sensor is enclosed within the second main body and is not disposed within the first main body.

4. The brake system according to claim 1, wherein the back plate extends from the first body to the second body and separates the second body from the friction material, so that the second body does not come into contact with the friction material.

5. The brake system according to claim 1, wherein the sensor unit is fixed to the back plate.

6. The brake system according to claim 1, wherein the first sensor is a thermistor.

7. The brake system according to claim 6, wherein the thermistor is configured to provide a signal indicating the temperature of the first body to the second sensor.

8. The second recovery described above is The thermistor receives the signal, An output signal, wherein the output signal is The serial number of the second sensor, The brake system according to claim 7, configured to generate an output signal including a temperature code based on the signal from the thermistor.

9. The brake system according to claim 8, wherein the controller is configured to receive the output signal from the second sensor via the data bus, determine the position of the sensor unit based on the serial number, and determine the temperature value based on the temperature code.

10. The brake system according to claim 8, wherein when the signal indicates a resistance less than a first resistance boundary value, the signal from the thermistor indicates the wear state of the friction material of the brake pad assembly.

11. The brake system according to claim 8, wherein when the signal indicates a resistance exceeding a second resistance boundary value, the signal from the thermistor indicates the wear state of the friction material of the brake pad assembly.

12. A method for controlling a brake system, wherein the method is The sensor unit provides a signal from a thermistor to a second sensor of the sensor unit, wherein the sensor unit is disposed on a brake pad assembly of a friction brake, and the signal indicates the temperature of the brake pad assembly. The second sensor generates an output signal that includes the serial number of the second sensor and a temperature code based on the signal from the thermistor. The output signal is communicated to the controller, The controller identifies the location of the sensor unit based on the serial number, The controller determines the temperature of the sensor unit based on the temperature code, A method comprising communicating the position and temperature of the sensor unit to a communication device using the controller.

13. The method according to claim 12, further comprising communicating the output signal to the controller via a data bus.

14. The method according to claim 12, further comprising communicating the position and temperature of the sensor unit to the communication device, by providing a notification to the communication device when the temperature exceeds a predetermined temperature value.

15. The method according to claim 12, further comprising mounting the sensor unit on the brake pad assembly, wherein, before the thermistor provides the signal, the first body of the sensor unit containing the thermistor extends from a first side of the back plate of the brake pad assembly disposed adjacent to the friction material of the brake pad assembly, and the second body of the sensor unit containing the thermistor extends from a second side of the back plate of the brake pad assembly disposed on the opposite side of the first side.

16. It is a brake system, First and second friction brakes, each of which is A brake pad assembly, wherein the brake pad assembly is A back plate having a first side and a second side disposed on the opposite side of the second side, A brake pad assembly comprising: a friction material extending from the first side and extending away from the second side; A sensor unit disposed on the back plate, wherein the sensor unit is A first body extending from the first side surface of the back plate and disposed in close proximity to the friction material, The first sensor is disposed inside the first main body, A second body extending from the second side surface of the back plate and connected to the first body, A sensor unit comprising a second sensor disposed inside the second main body and electrically connected to the first sensor, and a first and second friction brake comprising Controller and A wire harness, wherein the wire harness is A first resistor is electrically connected to the sensor unit of the first friction brake by a first conductor, The first resistor and the second resistor are electrically connected to the sensor unit of the second friction brake by a second conductor, wherein the first resistor and the second resistor have different electrical resistances. A brake system comprising a wire harness, which includes an electrically connected data bus that electrically connects the controller to the sensor unit of the first friction brake and the sensor unit of the second friction brake.

17. The brake system according to claim 16, wherein the second sensor of the sensor unit of the first friction brake is configured to measure the resistance value of the first resistor, generate a first position address based on the resistance value of the first resistor, and provide the first position address to the controller, and the first position address indicates the position of the sensor unit of the first friction brake.

18. The brake system according to claim 17, wherein the first resistor is disposed within the first connector plug of the wire harness, and the first connector plug is coupled to the connector plug of the sensor unit of the first friction brake.

19. The brake system according to claim 16, wherein the second sensor of the sensor unit of the second friction brake is configured to measure the resistance value of the second resistor, generate a second position address based on the resistance value of the second resistor, and provide the second position address to the controller, and the second position address indicates the position of the sensor unit of the second friction brake.

20. The brake system according to claim 19, wherein the second resistor is disposed within the second connector plug of the wire harness, and the second connector plug is coupled to the connector plug of the sensor unit of the second friction brake.

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