Wheel end braking device, braking system and vehicle

Abstract

The invention discloses a wheel end braking device, a braking system and a vehicle. The wheel end braking device comprises a braking unit, a parking unit and a wheel end controller, the braking unit comprises a braking motor and braking calipers, the braking motor is used for outputting braking torque to drive the braking calipers to output clamping force to a brake disc of a vehicle, and the parking unit is used for locking the braking motor. And in the process that the wheel end controller controls the braking unit to output the first clamping force for a first preset duration, the wheel end controller responds to the situation that the temperature of the braking motor is larger than or equal to a first temperature threshold value or the single-plate temperature of the wheel end controller is larger than or equal to a second temperature threshold value, and the parking unit is controlled to lock the braking motor. The probability that braking is lost due to the fact that the temperature of the braking motor is too high can be reduced, and braking safety of a vehicle is improved.

Description

Technical Field

[0001] The present application relates to the field of vehicle control technology, and in particular to a wheel-end braking device, a braking system and a vehicle. Background Art

[0002] Electromechanical brake (EMB) systems are rapidly developing due to their enhanced safety, faster response, and simpler structure. EMB systems typically consist of a brake motor and a brake caliper (also called a brake actuator), which is connected to the motor shaft of the brake motor. The brake motor drives the brake caliper to clamp and release the brake disc. During service braking, the brake motor in the EMB system drives the brake caliper to clamp the brake disc, thereby stopping the vehicle.

[0003] In many driving braking scenarios of electric vehicles, such as when the driver steps on the brakes for a long time waiting for a red light or the vehicle stops on a slope without turning off the engine, the brake motor of the electronic mechanical braking system will output torque for a long time and be in a stalled state. The long-term stalled state of the brake motor will cause the temperature of the brake motor winding to rise rapidly and lose the brake, affecting the braking safety of the vehicle. Summary of the Invention

[0004] The present application provides a wheel-end braking device, a braking system and a vehicle, which can reduce the probability of losing braking due to excessive temperature of the brake motor and improve the braking safety of the vehicle.

[0005] To achieve the above objectives, this application adopts the following technical solutions:

[0006] In a first aspect, a wheel-end braking device for a vehicle is provided, the wheel-end braking device including a braking unit, a parking unit and a wheel-end controller, the braking unit including a brake motor and a brake caliper, the brake motor being used to output braking torque to drive the brake caliper to output clamping force to the brake disc of the vehicle, and the parking unit being used to lock the brake motor; after the vehicle is braked until the vehicle speed is reduced to zero, the wheel-end controller being used to: while the braking unit continues to output a first clamping force for a first preset time, in response to the temperature of the brake motor being greater than or equal to a first temperature threshold or the temperature of a single board of the wheel-end controller being greater than or equal to a second temperature threshold, control the parking unit to lock the brake motor.

[0007] Based on the above technical solution, the wheel-end brake device includes a brake unit and a parking unit. The brake unit primarily outputs braking force to the brake disc during vehicle braking to enable the electric vehicle to complete the braking process, while the parking unit primarily outputs parking braking force to the brake disc to enable the vehicle to complete the parking process. During vehicle braking, the brake motor is used to output torque to drive the brake caliper to apply braking force to the brake disc. The brake motor is often in a stalled state, causing the brake motor temperature to rise. If the brake motor temperature is too high, the brake function may be lost, affecting the vehicle's braking safety.

[0008] The wheel-end brake device provided by the present application is a device that controls the parking unit to lock the brake motor so that the brake motor no longer outputs the braking torque after the vehicle is braked to the point where the vehicle speed is reduced to zero and the brake motor continues to output the first clamping force for a first preset time period. In this process, if the temperature of the brake motor is greater than or equal to the first temperature threshold, i.e., when it is overheated, the parking unit is controlled to lock the brake motor so that the brake motor no longer outputs the braking torque. This can prevent the brake motor from continuing to work when it is overheated, prevent the brake motor from burning out, and further reduce the probability of losing the brake due to excessive temperature of the brake motor, thereby improving the braking safety of the vehicle. Similarly, since the temperature of the single board will also cause the motor to heat up, when the temperature of the single board of the wheel-end controller is greater than or equal to the second temperature threshold, the brake motor may also overheat. At this time, the parking unit is controlled to lock the brake motor so that the brake motor no longer outputs the braking torque. This can also prevent the brake motor from continuing to work when it is overheated, prevent the brake motor from burning out, and further reduce the probability of losing the brake due to excessive temperature of the brake motor, thereby improving the braking safety of the vehicle.

[0009] For example, after the driver stops the vehicle and waits for a red light or during a braking stop on a slope, the brake motor continues to output a stall torque, causing the brake motor temperature to rise rapidly. In this case, the wheel-end brake device provided by the present application can use the parking unit to lock the brake motor, thereby releasing the torque of the brake motor and preventing the brake motor from continuously overheating.

[0010] In one possible design, after the vehicle's speed is reduced to zero, while the brake unit continues to output the first clamping force, the wheel-end controller is further configured to: in response to the temperature of the brake motor being less than a first temperature threshold and the temperature of the wheel-end controller's single plate being less than a second temperature threshold, control the brake unit to output the first clamping force for a first preset duration. Thus, when the vehicle is braked until the vehicle's speed is reduced to zero, while the brake unit continues to output the first clamping force, if the temperature of the brake motor and the temperature of the single plate remain within the set temperature thresholds during the first preset duration, the brake unit is controlled to output the first clamping force for the first preset duration. In other words, the parking unit will not be controlled to lock the brake motor during the first preset duration. This allows the vehicle to be braked while ensuring that the temperature of the brake motor remains within the temperature threshold, thereby improving the vehicle's braking safety.

[0011] In one possible design, after the vehicle brakes until its speed drops to zero, the wheel-end controller is further configured to control the parking unit to lock the brake motor in response to the brake unit continuing to output the first clamping force for a first preset duration. Thus, after the first preset duration, the parking unit is controlled to lock the brake motor, that is, only the brake motor is controlled to output braking torque for the first preset duration. The brake motor is locked because, after the first preset duration, the maximum stall duration that the brake motor can support has been exceeded, or the brake motor may have overheated after the first preset duration. This prevents damage to the brake motor, further reduces the probability of brake loss due to overheating of the brake motor, and improves the vehicle's braking safety.

[0012] In one possible design, the first clamping force is the clamping force indicated by the first brake signal. After the vehicle brakes until its speed is reduced to zero, the wheel-end controller is further configured to, in response to the second brake signal, control the brake unit to output a second clamping force for a second preset time period while controlling the brake unit to output the first clamping force for a first preset time period. The second clamping force is the clamping force indicated by the second brake signal, and the second preset time period is different from the first preset time period. Thus, when the brake signal changes while controlling the brake motor to continuously output braking torque, the maximum time period for which the brake motor continuously outputs braking torque also changes accordingly. Because the amount of heat generated by the brake motor varies under different clamping forces, the time period required for the brake motor to overheat also varies. Therefore, different maximum times for which the brake motor is allowed to continuously output braking torque are set under different clamping forces. This ensures that, under different clamping forces, the brake motor will not overheat when continuously outputting the braking torque required by the corresponding clamping force for the preset time period. This reduces the probability of brake failure due to excessive temperature in the brake motor, thereby improving vehicle braking safety.

[0013] In one possible design, after the vehicle brakes until its speed is reduced to zero, the wheel-end controller is configured to: during the process of controlling the brake unit to output the second clamping force for a second preset duration, in response to the temperature of the brake motor being greater than or equal to a first temperature threshold or the temperature of a single board of the wheel-end controller being greater than or equal to a second temperature threshold, control the parking unit to lock the brake motor. Similarly, during the process of controlling the brake motor to output the second clamping force for the second preset duration, if the temperature of the brake motor is greater than or equal to the first temperature threshold, i.e., overtemperature, the parking unit is controlled to lock the brake motor so that the brake motor no longer outputs braking torque. This prevents the brake motor from continuing to operate when overheated, prevents the brake motor from burning out, and thereby reduces the probability of brake loss due to excessively high brake motor temperature, thereby improving the braking safety of the vehicle. Similarly, since the temperature of the single board will also cause the motor to heat up, when the temperature of the single board of the wheel-end controller is greater than or equal to the second temperature threshold, the brake motor may also overheat. At this time, the parking unit is controlled to lock the brake motor so that the brake motor no longer continues to output braking torque. It can also prevent the brake motor from continuing to work when overheated, prevent the brake motor from burning out, and thus reduce the probability of losing braking due to excessive temperature of the brake motor, thereby improving the braking safety of the vehicle.

[0014] In one possible design, after the vehicle brakes until the vehicle speed is reduced to zero, in the process of receiving the second brake signal, the wheel-end controller is used to: in response to the temperature of the brake motor being less than the first temperature threshold and the temperature of the wheel-end controller board being less than the second temperature threshold, first control the brake unit to output the second clamping force for a second preset time period, and then control the parking unit to lock the brake motor. Similarly, after the second preset time period, the parking unit is controlled to lock the brake motor. Since, after the second preset time period, the maximum stall time that the brake motor can support may be exceeded, or the temperature of the brake motor may be overheated after the second preset time period, the brake motor is locked. This can avoid damage to the brake motor, further reduce the probability of losing the brake due to excessive temperature of the brake motor, and improve the braking safety of the vehicle.

[0015] In one possible design, the second clamping force is greater than the first clamping force, and the second preset duration is less than the first preset duration. Thus, as the clamping force increases, the heat generated by the brake motor's continuous output of braking torque increases, causing the brake motor's temperature to rise more rapidly. Therefore, by shortening the preset duration, the brake motor will not overheat when continuously outputting the braking torque required for the clamping force, even when the clamping force changes. This reduces the probability of brake loss due to excessive brake motor temperature, thereby improving vehicle braking safety.

[0016] In one possible design, the first preset duration is negatively correlated with the slope of the road on which the vehicle is located, and the second preset duration is negatively correlated with the slope of the road on which the vehicle is located. Because the clamping force required to maintain the vehicle stationary varies at different road slopes, the brake motor temperature caused by operation may also vary. Consequently, the time it takes for the brake motor to reach overtemperature may also vary. Therefore, setting the duration for the brake motor to output clamping force based on the road slope of the vehicle can ensure that the brake motor does not overheat during braking on different road slopes, reducing the probability of brake loss due to excessive brake motor temperature and improving vehicle braking safety. Furthermore, the higher the road slope, the greater the clamping force required to maintain the vehicle stationary, which in turn requires a greater braking torque from the brake motor, causing the brake motor temperature to rise more rapidly and shortening the time it takes for the brake motor to reach overtemperature. Therefore, setting the duration for the brake motor to output clamping force to be negatively correlated with the road slope can further ensure that the brake motor does not overheat on different road slopes. It can reduce the probability of losing brakes due to excessive temperature of the brake motor and improve the braking safety of the vehicle.

[0017] In one possible design, after the vehicle brakes until its speed decreases to zero and remains at zero for a third preset time period, the wheel-end controller is configured to: while the brake unit continues to output the first clamping force for the first preset time period, in response to the temperature of the brake motor being greater than or equal to a first temperature threshold or the temperature of the wheel-end controller's single board being greater than or equal to a second temperature threshold, control the parking unit to lock the brake motor; or, in response to the brake unit continuing to output the first clamping force for the first preset time period, control the parking unit to lock the brake motor. In this way, after the vehicle has been stationary for a period of time, and while the brake unit continues to output the first clamping force for the first preset time period, in response to the temperature of the brake motor or the single board exceeding the temperature threshold, the brake motor is locked. Alternatively, the brake motor is locked after the brake unit continues to output the clamping force for the first preset time period. This reduces the frequency of control execution and power consumption while minimizing the probability of brake loss due to excessive brake motor temperature and improving vehicle braking safety.

[0018] In one possible design, after controlling the parking unit to lock the brake motor, the wheel-end controller is further configured to control the parking unit to unlock the brake motor in response to a throttle signal. This allows the vehicle to start normally. Optionally, the throttle signal can come from an accelerator pedal or an intelligent driving system. The throttle signal can be received by a central controller, which can then transmit the throttle signal or an unlocking command generated based on the throttle signal to the wheel-end controller.

[0019] In one possible design, the wheel-end controller includes a control circuit, a brake motor power circuit and a parking motor power circuit, and the parking unit includes a parking motor, wherein: the brake motor power circuit includes a three-phase bridge arm, and the midpoint of the three-phase bridge arm of the brake motor power circuit is used to connect the three-phase winding of the brake motor; the parking motor power circuit includes a three-phase bridge arm, and the midpoint of the three-phase bridge arm of the parking motor power circuit is used to connect the three-phase winding of the parking motor; the control circuit is used to receive a braking signal and control the midpoint of the three-phase bridge arm of the brake motor power circuit to output a brake motor drive current or control the midpoint of the three-phase bridge arm of the parking motor power circuit to output a parking motor drive current.

[0020] In a second aspect, a braking system for a vehicle is provided, which includes four wheel-end braking devices and a central controller. The wheel-end braking device includes a braking unit, a parking unit and a wheel-end controller. The braking unit includes a brake motor and a brake caliper. The brake motor is used to output braking torque to drive the brake caliper to output clamping force to the brake disc of the vehicle, and the parking unit is used to lock the brake motor. After the vehicle is braked to the speed of the vehicle is reduced to zero, the central controller is used to: while the wheel-end braking device continues to output the first clamping force for a first preset time, in response to the temperature of the brake motor being greater than or equal to the first temperature threshold, or the temperature of the single board of the wheel-end controller being greater than or equal to the second temperature threshold, control the wheel-end braking device to lock the brake motor.

[0021] In one possible design, after the vehicle is braked to zero speed, while the wheel-end brake device continues to output the first clamping force, the central controller is also used to: in response to the temperature of the brake motor being less than a first temperature threshold and the temperature of a single board of the wheel-end controller being less than a second temperature threshold, first control the wheel-end brake device to output the first clamping force for a first preset time period, and then control the wheel-end brake device to lock the brake motor.

[0022] In one possible design, the first clamping force is the clamping force indicated by the first braking signal. After the vehicle is braked until the vehicle speed is reduced to zero, the central controller is also used to: in the process of controlling the wheel-end braking device to output the first clamping force for a first preset time, in response to the second braking signal, control the wheel-end braking device to output the second clamping force for a second preset time, the second clamping force is the clamping force indicated by the second braking signal, the second clamping force is greater than the first clamping force, and the second preset time is less than the first preset time.

[0023] In a third aspect, a vehicle is provided, comprising the wheel-end braking device as described in the first aspect and any one of its designs, or comprising the braking system as described in the second aspect and any one of its designs.

[0024] It should be noted that the technical effects brought about by any design in the above-mentioned second to third aspects can refer to the technical effects brought about by the corresponding design in the first aspect, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of a vehicle button provided in an embodiment of the present application;

[0026] Figure 2 A schematic structural diagram of a vehicle provided in an embodiment of the present application;

[0027] Figure 3 A schematic structural diagram of a braking system provided in an embodiment of the present application;

[0028] Figure 4 A schematic structural diagram of a wheel-end brake device provided in an embodiment of the present application;

[0029] Figure 5 A schematic structural diagram of a brake unit provided in an embodiment of the present application;

[0030] Figure 6 A schematic structural diagram of a parking unit provided in an embodiment of the present application;

[0031] Figure 7 A schematic diagram of locking a locking rod provided in an embodiment of the present application;

[0032] Figure 8 A schematic diagram of a control architecture provided in an embodiment of the present application;

[0033] Figure 9 A schematic diagram of another control architecture provided in an embodiment of the present application;

[0034] Figure 10 A schematic structural diagram of a wheel-end controller provided in an embodiment of the present application;

[0035] Figure 11 A schematic diagram of the operation of a braking system provided in an embodiment of the present application;

[0036] Figure 12 A timing diagram provided for an embodiment of the present application;

[0037] Figure 13 Another timing diagram provided in an embodiment of the present application;

[0038] Figure 14 A flowchart of a parking method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0039] In order to facilitate the clear description of the technical solutions of the embodiments of the present application, in the embodiments of the present application, words such as "first" and "second" are used to distinguish between identical items or similar items with substantially the same functions and effects. Those skilled in the art will understand that words such as "first" and "second" do not limit the quantity and execution order, and words such as "first" and "second" do not necessarily limit them to be different. The meaning of "multiple" refers to two or more. "And / or" in this article is merely a description of the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent three situations: A exists alone, A and B exist at the same time, and B exists alone.

[0040] In the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be interpreted as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0041] In addition, the network architecture and business scenarios described in the embodiments of the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided in the embodiments of the present application. Ordinary technicians in this field can know that with the evolution of network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0042] With the rapid development of electric vehicle technology, people's requirements for driving comfort, operability and safety have been further improved, and the braking system has been given more responsibilities and obligations. For example, the braking system can provide braking force for the wheels of electric vehicles. The current electric vehicle braking systems include electronic mechanical braking systems and electric hydraulic brake (EHB) systems. Compared with electronic hydraulic braking systems, electronic mechanical braking systems have the advantages of fast response speed, high precision, no fluid leakage, and flexible layout. They can significantly improve safety performance while reducing maintenance costs. The electronic mechanical braking system includes a wheel-end braking device (or wheel-end assembly), which usually includes a brake motor and a brake caliper. The brake caliper is connected to the motor shaft of the brake motor. The brake motor is used to drive the brake caliper to clamp or release the brake disc.

[0043] In some scenarios, the electronic parking brake (EPB) system can be used as part of the braking system and can be integrated into the wheel-end brake device of the electronic mechanical braking system. The electronic parking brake system can lock the brake motor through a separate EPB motor to achieve automatic control. In some implementations, the function of the electronic parking brake system to lock the brake motor (also called the EPB function) is activated by the driver. Figure 1 As shown, the vehicle can be installed with a start button for the EPB function, such as an electronic parking brake control key. When the driver presses the electronic parking brake control key, a parking signal will be transmitted to the controller of the electronic parking brake (EPB) system, and the controller will drive the EPB motor to lock the brake motor based on the parking signal.

[0044] In other implementations, the function of the electronic parking brake system to lock the brake motor can be automatically activated under certain working conditions: for example, when the vehicle is turned off, the vehicle will automatically start the electronic parking system to lock the brake motor; for example, when the vehicle is stationary but not turned off and the auto vehicle hold (AVH) function is turned on, if it is detected that the driver's seat belt is loosened or the door on the driver's side is open, the electronic parking system will lock the brake motor. For example, when the vehicle is stationary but not turned off and the AVH function is turned on, if it is detected that the driver's seat belt is not loosened and the driver's door is not open (such as a scene waiting for a traffic light), the AVH function will be executed in the first 5 minutes. After 5 minutes, the AVH function will exit and the electronic parking system will lock the brake motor, etc. It can be understood that the AVH function is a function that assists the driver's operation by automatically maintaining the brakes when the vehicle is stationary. That is, the driver does not need to step on the brake pedal to keep the vehicle stationary, which can avoid unnecessary sliding when the vehicle is parked. For example, when the driver starts to drive the vehicle, he can Figure 1 The start button of the AVH function shown, such as the automatic parking control button, activates the AVH function of the vehicle. Subsequently, when the driver brakes and decelerates the vehicle to a standstill, the AVH function automatically maintains the brake pressure to keep the vehicle stationary.

[0045] In the above implementation, the automatic start timing of the EPB function depends only on the external factors of the vehicle (such as seat belts, slipping, etc.), and does not take into account the influence of internal factors of the vehicle (such as the temperature of the brake motor, the temperature of the wheel end controller board, the clamping force output by the brake caliper, etc.). These internal factors of the vehicle are very important for the braking safety of the vehicle. For example: in many driving braking scenarios of the vehicle, such as the driver stepping on the brake for a long time to wait for a red light or the vehicle does not turn off the engine to stop on a slope, the brake motor of the electronic mechanical braking system will output torque for a long time and be in a stalled state. If the brake motor is in a stalled state for a long time, the temperature of the brake motor winding will rise rapidly and the brake will be lost, which will affect the braking safety of the vehicle. Therefore, in order to solve the problem of losing the brake due to excessive temperature of the brake motor, it is very important to start the EPB function at the right time.

[0046] Based on this, an embodiment of the present application provides a wheel-end braking device, a braking system and a vehicle. When the temperature of the brake motor is too high or the temperature of a single board of the wheel-end controller (which may be simply referred to as the single board temperature) is too high, the parking unit locks the brake motor, which can reduce the probability of losing braking due to excessive temperature of the brake motor and improve the braking safety of the vehicle.

[0047] The technical solutions provided in the embodiments of the present application are mainly applied to the braking process of a vehicle. Specifically, the vehicle can be any of different types of vehicles such as a car, a truck, a passenger bus, etc., and can also be a transport device for carrying people or goods such as a tricycle, a two-wheeled vehicle, a train, etc., and can be other types of vehicles driven by traditional power energy or other power batteries. Vehicles include but are not limited to pure electric vehicles (pure electric vehicle / battery electric vehicle, pureEV / battery EV), hybrid electric vehicles (hybrid electric vehicle, HEV), range-extended electric vehicles (REEV), plug-in hybrid electric vehicles (PHEV), new energy vehicles (NEV), etc.

[0048] For example, Figure 2 This is a schematic diagram of the structure of the vehicle provided in the embodiment of the present application. Figure 2As shown, the vehicle 200 includes wheels 10 and a braking system 20. Optionally, the vehicle 200 may further include a brake pedal 30 and a parking button 40, by which the driver can control the driving state of the vehicle 200. For example, during driving, when the vehicle 200 needs to brake, the driver can step on the brake pedal 30, and the braking system 20 can receive the braking signal from the brake pedal 30 and output friction braking force to the brake disc based on the braking signal to control the braking of the vehicle 200. Alternatively, the driver can press the parking button 40, and the braking system 20 receives the parking signal from the electronic parking brake system and controls the parking of the vehicle 200 based on the parking signal.

[0049] Figure 3 This is a schematic diagram of the structure of the braking system 20 provided in the embodiment of the present application. Figure 3 As shown, the braking system 20 includes four wheel-end brake devices 310 and a central controller 320. The central controller 320 is configured to control the wheel-end brake devices 310 to brake and / or park the vehicle based on the travel of the brake pedal 30 and the state of the parking button 40. For example, when the driver depresses the brake pedal 30, the central controller 320 receives a braking signal from the brake pedal 30 and outputs a braking torque signal to the four wheel-end brake devices 310. The wheel-end brake devices 310 are configured to receive the braking torque signal and output a friction braking force to the brake discs according to the braking torque signal.

[0050] Optional, Figure 2 The vehicle 200 shown may also include a low-voltage battery ( Figure 3 (not shown), the low-voltage battery can provide current for the wheel-end brake device 310.

[0051] Figure 4 and Figure 5 This is a schematic diagram of the structure of the wheel end brake device 310 provided in the embodiment of the present application. Figure 4 As shown, the wheel end braking device 310 includes a wheel end controller 410 , a braking unit 420 and a parking unit 430 .

[0052] like Figure 5 As shown, the brake unit 420 includes a brake motor 421 and a brake caliper 422. The brake motor 421 is used to output a braking torque to drive the brake caliper to output a clamping force to the brake disc 440 (or brake disc 440) of the vehicle 200. The clamping force is used to generate friction between the brake unit 420 and the brake disc 440. The brake unit 420 may include a thrust bearing, a ball screw assembly, and a piston. The brake unit 420 is used to convert the rotational torque of the brake motor 421 into a linear clamping force, and pressurize the brake disc 440 through the friction plate to achieve a braking effect. Figure 4For detailed description of each module in the braking unit 420, please refer to the description in the related art.

[0053] The parking unit 430 is used to lock the brake motor 421 .

[0054] Optionally, one or more of the four wheel-end brake devices 310 may include a parking unit 430. During operation of the vehicle 200, when the central controller 320 receives a parking signal, the central controller 320 transmits the parking signal to the wheel-end controller 410. The wheel-end controller 410 first controls the brake motor 421 to drive the brake caliper 422 to clamp the brake disc 440. After the brake disc 440 is clamped, the wheel-end controller 410 controls the parking unit 430 to lock the brake motor 421, so that the brake caliper 422 remains in the state of clamping the brake disc 440 and does not release, thereby keeping the vehicle 200 in the parked state.

[0055] Alternatively, the parking signal may come from an electronic parking brake system. When the driver presses the parking button 40, the electronic parking brake system generates a parking signal and transmits the parking signal to the central controller 320. The central controller 320 further transmits the parking signal to the wheel-end controller 410. In one embodiment, the electronic parking brake system may also be directly connected to the wheel-end controller 410. In other words, the parking signal generated by the electronic parking brake system may be transmitted directly to the wheel-end controller 410 without passing through the central controller 320. This shortens the transmission path of the parking signal, thereby improving the accuracy and control speed of the parking controller.

[0056] Alternatively, the parking signal may come from another parking system. For example, when the driver shifts the vehicle into P gear, a parking signal may be generated. Alternatively, the parking signal may come from an automatic parking system (Auto Hold). The wheel-end controller 410 may directly receive the parking signal, or the central controller 320 may first receive the parking signal and then send the parking signal to the wheel-end controller 410.

[0057] Figure 6 This is a schematic diagram of the structure of the parking unit 430 provided in the embodiment of the present application. Figure 6 As shown, the parking unit 430 includes a parking motor 431 and a locking rod 432. The locking rod 432 includes a pawl and a ratchet that cooperate with each other. The pawl is mounted on the rotor of the parking motor 431. When the parking motor 431 rotates, it drives the pawl to rotate with the rotation of the parking motor 431 rotor. The ratchet is mounted on the rotor of the brake motor 421. When the brake motor 421 rotates, it drives the ratchet to rotate with the rotation of the brake motor 421 rotor. When the vehicle is parked, the rotation of the parking motor 431 drives the pawl to rotate, and the pawl can be locked into the gear slot of the ratchet, thereby locking the brake motor 421.

[0058] Figure 7 This is a schematic diagram of the process of locking the brake motor 421 by the locking rod 432 provided in an embodiment of the present application. Figure 7 (a) is a schematic diagram when parking is not performed. When parking is not performed, the pawl is outside the inter-tooth groove of the ratchet wheel, and the rotor of the brake motor 421 can rotate freely, that is, the brake motor 421 is not locked. Figure 7 (b) in the figure shows that when parking, the pawl is stuck in the inter-tooth groove of the ratchet wheel, and the rotor of the brake motor 421 is locked and cannot rotate freely. Since the brake motor 421 cannot rotate, the brake caliper 422 can always maintain a clamping state on the brake disc 440, so that the vehicle 200 is in a parking state.

[0059] When parking, the parking motor and the brake motor in the embodiment of the present application can rotate at the same time. That is to say, while the parking motor rotates to drive the pawl close to the ratchet, the brake motor rotates in the opposite direction to drive the ratchet to rotate. This makes it easier for the pawl to be stuck in the inter-tooth groove of the ratchet, thereby improving the success rate of parking and the safety and reliability of vehicle operation.

[0060] Figure 8 and Figure 9 Schematic diagrams of two control architectures provided in embodiments of the present application.

[0061] Figure 8 It is a centralized control architecture. Figure 8 As shown, the central controller 320 can be used to receive the braking signal and the temperature signal output by the temperature sensor. The braking signal can be used to instruct the wheel-end controller 410 to control the brake motor 421 to output the braking torque, thereby driving the brake caliper 422 to output the clamping force to the brake disc 440. The temperature sensor can be used to monitor at least one of the temperature of the brake motor 421 and the temperature of the single plate. Optionally, the number of temperature sensors can be one or more. Optionally, a temperature sensor can be configured for each wheel-end braking device 310. Accordingly, the temperature signal includes at least one of the brake motor temperature signal and the single plate temperature signal. The temperature signal can be used to determine whether the brake motor 421 or the single plate is overheated, and then determine whether to control the parking unit 430 to lock the brake motor 421.

[0062] Figure 9 For distributed control architecture. Figure 9 As shown, the wheel end controller 410 can directly receive the braking signal and the temperature signal output by the temperature sensor. Figure 8 Corresponding introduction.

[0063] Figure 10This is a schematic diagram of the structure of the wheel end controller 410 provided in the embodiment of the present application. Figure 10 As shown, the wheel-end controller 410 includes a control circuit 1010, a brake motor power circuit 1020, and a parking motor power circuit 1030. The brake motor power circuit 1020 includes a three-phase bridge arm, and the midpoints of the three-phase bridge arms of the brake motor power circuit 1020 are used to connect to the three-phase windings of the brake motor 421. The midpoints of each phase of the three-phase bridge arm of the brake motor power circuit 1020 are labeled A, B, and C, respectively, and each phase winding of the brake motor 421 is labeled a, b, and c, respectively.

[0064] The parking motor power circuit 1030 includes three-phase bridge arms, the midpoints of which are connected to the three-phase windings of the parking motor 431. The midpoints of each of the three-phase bridge arms of the parking motor power circuit 1030 are labeled U, V, and W, respectively, and each phase winding of the parking motor 431 is labeled u, v, and w, respectively.

[0065] Each phase bridge arm may include two first and second switching tubes connected in series, and two diodes connected in anti-parallel with the switching tubes. For example, the A-phase bridge arm of the brake motor power circuit 1020 includes a first switching tube S1 and a second switching tube S2 connected in series, a diode D1 connected in anti-parallel with the first switching tube S1, and a switching tube D2 connected in anti-series with the second switching tube S2. The V-phase bridge arm of the parking motor power circuit 1030 includes a first switching tube S3 and a second switching tube S4 connected in series, a diode D3 connected in anti-parallel with the first switching tube S3, and a switching tube D4 connected in anti-series with the second switching tube S4. And so on.

[0066] The control circuit 1010 is used to control the brake motor power circuit 1020 to output a brake motor driving current to drive the brake motor 421 to operate, or to control the parking motor power circuit 1030 to output a brake motor driving current to drive the parking motor 431 to operate.

[0067] In an embodiment of the present application, the control circuit 1010 can directly generate a parking signal or receive a braking signal to control the brake motor power circuit 1020 or the parking motor power circuit 1030. The control circuit 1010 can also control the brake motor power circuit 1020 or the parking motor power circuit 1030 according to the instructions of the central controller 320 (such as a braking torque signal, a parking signal light).

[0068] The following combination Figures 1 to 10 The structure shown introduces the technical solution provided by the embodiment of this application.

[0069] In some embodiments, after the vehicle brakes until the vehicle speed is reduced to zero, the wheel-end controller 410 may continue to receive the first braking signal. In response to the first braking signal, the wheel-end controller 410 controls the braking unit 420 to continue to output the first clamping force for a first preset duration. The first clamping force is the clamping force indicated by the first braking signal. Optionally, in this embodiment, the first braking signal may be at least one of a pedal travel signal, a braking signal of an AVH system, a braking signal of an intelligent driving system, a braking signal of a vehicle stability system, a control signal of a central controller (such as a braking torque signal determined based on the braking signal), and the like.

[0070] In some embodiments, the first preset duration can be a preset fixed duration, which can be less than or equal to a duration threshold. The duration threshold can be the minimum duration of braking after the vehicle brakes to zero speed and the brake motor continuously outputs braking force until the temperature overheats. This ensures that the temperature of the brake motor remains within the overtemperature threshold while the brake motor continuously outputs braking torque, thereby reducing the probability of brake loss due to excessively high brake motor temperature and improving vehicle braking safety.

[0071] In yet other embodiments, the first preset time duration can also be determined based on the road gradient on which the vehicle is located. As a specific implementation, the first preset time duration can be negatively correlated with the road gradient on which the vehicle is located. Because the clamping force required to maintain the vehicle stationary varies at different road gradients, the brake motor temperature caused by the brake motor's operation may also vary. Consequently, the time it takes for the brake motor to reach overtemperature may also vary. Therefore, setting the time duration during which the brake motor outputs the clamping force based on the road gradient on which the vehicle is located can ensure that the brake motor does not overheat when the vehicle is braking at different road gradients, reducing the probability of brake failure due to excessive brake motor temperature and improving vehicle braking safety. Furthermore, the higher the road gradient, the greater the clamping force required to maintain the vehicle stationary, which in turn requires a greater braking torque output by the brake motor, causing the brake motor temperature to rise more rapidly and shortening the time it takes for the brake motor to reach overtemperature. Therefore, setting the time duration during which the brake motor outputs the clamping force to be negatively correlated with the road gradient can further ensure that the brake motor does not overheat at different road gradients. It can reduce the probability of losing brakes due to excessive temperature of the brake motor and improve the braking safety of the vehicle.

[0072] In yet other embodiments, the first preset duration can also be determined based on the first clamping force. That is, the preset durations corresponding to different clamping forces are different. This ensures that, under different clamping forces, the brake motor will not overheat if it continuously outputs the braking torque required by the corresponding clamping force for the preset duration. This reduces the probability of brake failure due to overheating of the brake motor, thereby improving vehicle braking safety.

[0073] For example, when the road slope is 30 degrees and the first clamping force is 20 kN, the first preset duration can be 5 minutes. When the road slope is 40 degrees and the first clamping force is 25 kN, the first preset duration can be 3 minutes. When the road slope is 0 degrees (i.e., flat ground) and the first clamping force is 16 kN, the first preset duration can be 15 minutes, 10 minutes, etc. There is no theoretical limit to the first preset duration in this scenario. It will be understood that the preset values ​​described in the embodiments of the present application are only exemplary explanations made for ease of understanding, and can be set by developers according to actual needs.

[0074] In the above embodiment, as one possible implementation, when the brake unit 420 continues to output the first clamping force for a first preset duration, the temperature of the brake motor 421 included in the brake unit 420 may be too high, or the temperature of a single board of the wheel-end controller 410 may be too high. In this case, the wheel-end controller 410 controls the parking unit 430 to lock the brake motor 421 in response to the temperature of the brake motor 421 being greater than or equal to a first temperature threshold, or the temperature of the single board of the wheel-end controller 410 being greater than or equal to a second temperature threshold, while the brake unit 420 continues to output the first clamping force for the first preset duration. In other words, the wheel-end controller 410 controls the brake unit 420 to output the first clamping force for a duration that is less than the first preset duration. Thus, when the brake motor is controlled to output a first clamping force for a first preset time period, if the temperature of the brake motor is greater than or equal to the first temperature threshold, i.e., it is overheated, the parking unit is controlled to lock the brake motor so that the brake motor no longer outputs the braking torque. This can prevent the brake motor from continuing to operate when overheated, prevent the brake motor from burning out, and thus reduce the probability of losing the brake due to excessive temperature of the brake motor, thereby improving the braking safety of the vehicle. Similarly, since the temperature of the single board will also cause the motor to heat up, when the temperature of the single board of the wheel-end controller is greater than or equal to the second temperature threshold, the brake motor may also overheat. At this time, the parking unit is controlled to lock the brake motor so that the brake motor no longer outputs the braking torque. This can also prevent the brake motor from continuing to operate when overheated, prevent the brake motor from burning out, thereby reducing the probability of losing the brake due to excessive temperature of the brake motor, thereby improving the braking safety of the vehicle.

[0075] Optionally, the first temperature threshold and the second temperature threshold can be different in embodiments of the present application. For example, the first temperature threshold can be 160°C, 180°C, 200°C, etc., and the second temperature threshold can be 150°C, 140°C, etc. The first temperature threshold and the second temperature threshold can be set by the developer according to actual needs. In some implementations, the first temperature threshold can be less than the temperature corresponding to the failure of the brake motor due to high temperature, and the second temperature threshold can be less than the temperature at which the single board is burned out due to high temperature. In this way, the probability of losing braking due to the high temperature of the brake motor can be further reduced, and the braking safety of the vehicle can be improved.

[0076] As another possible implementation, during the process in which the brake unit 420 outputs the first clamping force for the first preset duration, the temperature of the brake motor 421 included in the brake unit 420 and the single board temperature of the wheel end controller 410 can always be maintained within the temperature threshold. At this time, the wheel end controller 410 can first control the brake unit 420 to output the first clamping force for the first preset duration, and then control the parking unit to lock the brake motor 421 in response to the temperature of the brake motor 421 being less than the first temperature threshold and the single board temperature of the wheel end controller 410 being less than the second temperature threshold. That is, in this implementation, the duration for which the wheel end controller 410 controls the brake unit 420 to output the first clamping force is the first preset duration. In this way, when the brake unit is controlled to continuously output the clamping force for the preset duration, the temperature of the brake motor and the single board temperature can always be within the set temperature threshold. At this time, the parking unit is controlled to lock the brake motor at the end of the preset duration. That is, the brake motor is only controlled to output the brake torque for the first preset duration. Since the maximum stall duration that the brake motor can support is exceeded after the first preset duration, or the temperature of the brake motor can also be too high after the first preset duration, the brake motor is locked. The brake motor can be prevented from being damaged, the probability of losing braking due to the high temperature of the brake motor can be further reduced, and the braking safety of the vehicle can be improved.

[0077] In some embodiments, the brake motor 421 is provided with a temperature sensor for monitoring the temperature of the brake motor 421. In some implementations, the temperature sensor can be provided on the housing surface of the brake motor 421, at the windings of the brake motor 421, or at the stator and rotor of the brake motor 421. In other words, the temperature of the brake motor 421 referred to in this application can be the housing temperature, winding temperature, stator temperature, or rotor temperature of the brake motor 421. In other implementations, the temperature of the brake motor 421 refers to the highest temperature among the temperatures at various locations in the motor. For example, the temperature sensor simultaneously monitors the housing temperature, winding temperature, stator temperature, or rotor temperature of the brake motor 421, and then takes the highest temperature as the temperature of the brake motor 421. In still other implementations, the temperature of the brake motor 421 refers to the average temperature among the temperatures at various locations in the motor. For example, the temperature sensor simultaneously monitors the housing temperature, winding temperature, stator temperature, or rotor temperature of the brake motor 421, and then takes the average of these temperatures as the temperature of the brake motor 421.

[0078] In other embodiments, a temperature sensor may also be provided on a single board of the wheel-end controller 410 , and the temperature sensor may be used to monitor the temperature of the single board of the wheel-end controller 410 .

[0079] In some embodiments, the wheel-end controller 410 can directly receive temperature signals from various temperature sensors and perform the aforementioned control operations when the temperature of the brake motor is greater than or equal to a first temperature threshold, or when the temperature of a single board of the wheel-end controller is greater than or equal to a second temperature threshold. Alternatively, the aforementioned control actions can be performed according to instructions from the central controller 320 when the temperature of the brake motor or the single board exceeds the corresponding temperature threshold. That is, the central controller 320 receives temperature signals from temperature sensors and, when the temperature of the brake motor or the single board exceeds the corresponding temperature threshold, issues a control instruction to control the wheel-end controller 410 to perform the aforementioned control actions. In other words, the wheel-end controller 410 can respond directly to the temperature of the brake motor or the single board, or indirectly to the temperature of the brake motor or the single board.

[0080] The following first introduces the process of the wheel end controller 410 indirectly responding to the brake motor temperature or the single board temperature. Figure 11 As shown, the central controller 320 can be connected to one or more of the brake pedal and the AVH system. After the vehicle brakes to zero speed, it continues to receive at least one of the following: a pedal travel signal from the brake pedal and a brake signal from the AVH system (hereinafter referred to as the brake signal). The central controller 320 also receives temperature signals (such as at least one of a motor temperature signal and a board temperature signal) monitored by a temperature sensor.

[0081] For example, after receiving a brake signal, the central controller 320 sends a first control signal (i.e., a first brake signal) to the wheel-end controller 410 based on the brake signal. This first control signal is used to instruct the wheel-end controller 410 to control the brake unit 420 to output a first clamping force for a first preset duration. Then, within the first preset duration, the central controller 320 receives a temperature signal and, based on this temperature signal, determines that the temperature of the brake motor 421 is greater than or equal to a first temperature threshold, or that the temperature of the single board is greater than or equal to a second temperature threshold. Then, the central controller 320 sends a second control signal (i.e., a parking signal) to the wheel-end controller 410. This second control signal is used to instruct the wheel-end controller 410 to control the parking unit 430 to lock the brake motor 421.

[0082] For another example, after receiving a brake signal, the central controller 320 sends a first control signal to the wheel-end controller 410 based on the brake signal. This first control signal instructs the wheel-end controller 410 to control the brake unit 420 to output a first clamping force for a first preset duration. Then, within the first preset duration, the central controller 320 receives a temperature signal and determines based on the temperature signal that the temperature of the brake motor 421 is consistently below a first temperature threshold, and the board temperature is consistently below a second temperature threshold. At the end of the first preset duration, the central controller 320 sends a second control signal to the wheel-end controller 410. This second control signal instructs the wheel-end controller 410 to control the parking unit 430 to lock the brake motor 421.

[0083] In this way, the central controller executes the algorithms required for various judgment operations, while the wheel-end controllers only need to execute the central controller's commands, making the wheel-end controller development simpler. Furthermore, the central controller's computing power is superior to that of the wheel-end controllers, which in turn makes the control process more precise.

[0084] The above describes the process by which the wheel-end controller 410 indirectly responds to the brake motor temperature or the board temperature. The following describes the process by which the wheel-end controller directly responds to the brake motor temperature or the board temperature. For example, the wheel-end controller 410 can be connected to one or more of the brake pedal and the AVH system to receive at least one of a pedal travel signal from the brake pedal and a braking signal from the AVH system. In this embodiment, the pedal travel signal from the brake pedal and the braking signal from the AVH system are the first braking signal. The wheel-end controller 410 can also receive a temperature signal from a temperature sensor.

[0085] For example, after receiving a first brake signal, the wheel-end controller 410 can directly control the brake unit 420 to output a first clamping force for a first preset duration in response to the first brake signal. Then, within the first preset duration, if the wheel-end controller 410 receives a temperature signal and determines, based on the temperature signal, that the temperature of the brake motor 421 is greater than or equal to a first temperature threshold, or that the board temperature is greater than or equal to a second temperature threshold, the wheel-end controller 410 can directly control the parking unit 430 to lock the brake motor 421. In other words, the wheel-end controller 410 can directly output a parking signal to the parking unit 430, and in response to the parking signal, the parking unit 430 locks the brake motor 421.

[0086] For another example, after receiving a first brake signal, the wheel-end controller 410 can directly control the brake unit 420 to output a first clamping force for a first preset duration in response to the first brake signal. Then, within the first preset duration, the wheel-end controller 410 receives a temperature signal and determines, based on the temperature signal, that the temperature of the brake motor 421 is consistently below a first temperature threshold, and that the board temperature is consistently below a second temperature threshold. At the end of the first preset duration, the wheel-end controller 410 directly controls the parking unit 430 to lock the brake motor 421.

[0087] In this way, the wheel-end controller directly receives the temperature signal and the braking signal, and controls the braking unit and the parking unit, which can shorten the signal transmission link and make the control process more accurate.

[0088] Of course, in other implementations, the central controller 320 may also receive either the brake signal or the temperature signal output by the temperature sensor. In other words, the wheel-end controller 410 may also directly receive either the brake signal or the temperature signal output by the temperature sensor. For example, the central controller 320 may only receive the brake signal, while the wheel-end controller 410 may directly receive the temperature signal output by the temperature sensor. In this manner, after receiving the brake signal, the central controller 320 outputs a first control signal to the wheel-end controller 410. In response to this first control signal, the wheel-end controller 410 controls the brake motor 421 to output a corresponding braking torque, driving the brake caliper 422 to apply a clamping force to the brake disc 440 for a first preset duration. If, within the first preset duration, the wheel-end controller 410 receives the temperature signal and determines, based on the temperature signal, that the temperature of the brake motor 421 is greater than or equal to a first temperature threshold or that the temperature of the single plate is greater than or equal to a second temperature threshold, it no longer responds to the first control signal sent by the central controller 320 and instead outputs a parking signal, controlling the parking unit 430 to lock the brake motor 421.

[0089] Similarly, if the wheel-end controller 410 receives a temperature signal within a first preset time period and determines, based on the temperature signal, that the temperature of the brake motor 421 is consistently below a first temperature threshold or that the board temperature is consistently below a second temperature threshold, the wheel-end controller 410 may respond to the first control signal for the first preset time period. Subsequently, at the end of the first preset time period, the wheel-end controller 410 no longer responds to the first control signal and instead outputs a parking signal to control the parking unit 430 to lock the brake motor 421.

[0090] For another example, the central controller 320 receives a temperature signal from a temperature sensor, and the wheel-end controller 410 directly receives a brake signal. Thus, after receiving the brake signal, the wheel-end controller 410 can directly control the brake motor 421 to output a braking torque for a first preset duration, thereby driving the brake caliper 422 to output a corresponding clamping force to the brake disc 440 for a first preset duration. Then, within the first preset duration, when the central controller 320 receives the temperature signal and determines, based on the temperature signal, that the temperature of the brake motor 421 is greater than or equal to a first temperature threshold or that the single board temperature is greater than or equal to a second temperature threshold, it sends a second control signal to the wheel-end controller 410. After receiving the second control signal, the wheel-end controller 410 no longer responds to the brake signal, but instead controls the parking unit 430 to lock the brake motor 421 based on the second control signal.

[0091] Similarly, if the central controller 320 receives the temperature signal within the first preset time period and determines based on the temperature signal that the temperature of the brake motor 421 is consistently below the first temperature threshold or the board temperature is consistently below the second temperature threshold, the central controller 320 may send the second control signal to the wheel-end controller 410 after the first preset time period expires.

[0092] In some embodiments, when the wheel-end controller 410 controls the brake unit 420 to output the first clamping force, the brake signal may change, that is, the clamping force indicated by the brake signal may change. For example, when the driver increases the pedal pressure, or the AVH system triggers the anti-slope function, the brake signal will become larger, and the clamping force indicated by the brake signal will also increase. In the process of controlling the brake unit 420 to output the first clamping force for a first preset time, the wheel-end controller 410 responds to the second brake signal and controls the brake unit 420 to output the second clamping force for a second preset time. The second clamping force is the clamping force indicated by the second brake signal. Optionally, in this embodiment, the second brake signal can also be at least one of a pedal travel signal, a brake signal of the AVH system, a brake signal of the intelligent driving system, a brake signal of the vehicle body stability system, and a control signal of the central controller.

[0093] In some embodiments, the first preset time length is different from the second preset time length. In this way, when controlling the brake motor to continuously output the braking torque, if the braking signal changes, the maximum time length for controlling the brake motor to continuously output the braking torque also changes accordingly. Since the amount of heat generated by the brake motor is different under different clamping forces, the time length required for the brake motor to reach overheating is also different. Therefore, under different clamping forces, different maximum time lengths for allowing the brake motor to continuously output the braking torque are set. It can be ensured that under different clamping forces, when the brake motor continuously outputs the braking torque required by the corresponding clamping force within the preset time length, the brake motor will not overheat. It can reduce the probability of losing braking due to excessive temperature of the brake motor and improve the braking safety of the vehicle.

[0094] Similarly, in some embodiments, the second preset time period can be determined based on the second clamping force. Alternatively, the second preset time period can also be determined based on one or more of the time period during which the brake caliper outputs the first clamping force, the magnitude of the first clamping force, and the like.

[0095] In some embodiments, the second clamping force is greater than the first clamping force, and the second preset duration is less than the first preset duration. Thus, as the clamping force increases, the heat generated by the brake motor's continuous output of braking torque increases, causing the brake motor's temperature to rise more rapidly. Therefore, by reducing the preset duration, the brake motor will not overheat when continuously outputting the braking torque required by the clamping force, even when the clamping force changes. This reduces the probability of brake loss due to excessively high brake motor temperature, thereby improving vehicle braking safety.

[0096] Likewise, in some embodiments, the second preset duration may also be determined based on the gradient of the road the vehicle is on. As a specific implementation, the second preset duration may be negatively correlated with the gradient of the road the vehicle is on.

[0097] In some embodiments, when the wheel-end controller 410 controls the brake unit 420 to output the second clamping force for a second preset duration, the temperature of the brake motor 421 or the temperature of a single board of the wheel-end controller 410 may also be too high. In this case, in response to the temperature of the brake motor 421 being greater than or equal to a first temperature threshold, or the temperature of the single board of the wheel-end controller 410 being greater than or equal to a second temperature threshold, the wheel-end controller 410 controls the parking unit 430 to lock the brake motor 421. In other words, the duration for which the wheel-end controller 410 controls the brake motor 421 to output the second clamping force is less than the second preset duration.

[0098] In other embodiments, when the wheel-end controller 410 is controlling the brake unit 420 to output the second clamping force for a second preset duration, that is, when receiving the second brake signal, the temperature of the brake motor 421 and the temperature of the single board of the wheel-end controller 410 may remain within the temperature threshold. At this time, in response to the temperature of the brake motor 421 being less than the first temperature threshold and the temperature of the single board of the wheel-end controller 410 being less than the second temperature threshold, the wheel-end controller 410 may first control the brake unit 420 to output the second clamping force for a second preset duration, and then control the parking unit to lock the brake motor 421. In other words, in this implementation, the wheel-end controller 410 controls the brake unit 420 to output the second clamping force for a duration equal to the second preset duration.

[0099] For the relevant implementation of the second preset duration control process here, reference may be made to the relevant implementation of the first preset duration control process described above.

[0100] In some embodiments, the wheel-end controller 410 may execute the above-described control process again when the vehicle has been stationary for a period of time. Optionally, the vehicle's stationary state may be determined based on at least one of the vehicle speed and the wheel speed. For example, after the vehicle has been braked to zero speed and the vehicle speed has remained zero for a third preset time period, the wheel-end controller 410 may control the parking unit to lock the brake motor in response to the temperature of the brake motor being greater than or equal to a first temperature threshold or the temperature of the wheel-end controller board being greater than or equal to a second temperature threshold while the brake unit continues to output the first clamping force for the first preset time period. Alternatively, the wheel-end controller may control the parking unit to lock the brake motor in response to the brake unit continuing to output the first clamping force for the first preset time period. In this way, executing the control process of the embodiments of the present application again after the vehicle has been stationary for a period of time can reduce the frequency and power consumption of executing the control process while ensuring that the probability of brake loss due to excessively high brake motor temperature is reduced, thereby improving the braking safety of the vehicle.

[0101] In other embodiments, the wheel-end controller 410 may also control the brake unit 420 to output the first clamping force for a first preset duration when the vehicle reaches a stationary state. For example, the wheel-end controller 410 may control the brake unit 420 to output the first clamping force for a first preset duration when responding to the first braking signal and the vehicle speed or wheel speed is zero.

[0102] In some embodiments, after controlling the parking unit 430 to lock the brake motor 421, the wheel-end controller 410 may also control the parking unit 430 to unlock the brake motor, such as when the vehicle is starting. For example, the wheel-end controller 410 controls the parking unit 430 to unlock the brake motor 421 in response to a throttle signal, or in response to the throttle signal being greater than or equal to a preset threshold. This allows the vehicle to start normally.

[0103] For example, Figure 12 A schematic diagram of a control process provided by an embodiment of the present application is shown. Figure 12 As shown in (1), between time 0 and t0, the central controller 320 or the wheel-end controller 410 receives a braking signal. In response to the braking signal, the brake motor 421 continuously outputs a braking torque during this time period. This braking torque drives the brake caliper 422 to output a clamping force to the brake disc 440 to clamp the brake disc 440. The speed of the vehicle 200 gradually begins to decrease and drops to zero at time t0. During this time period, the temperature of the brake motor 421 remains below the first temperature threshold.

[0104] During the time period from t0 to t1 (i.e., the third preset duration), the vehicle is in a braked stop state. At time t1, the driver continues to depress the pedal, or releases the pedal and the AVH system requests braking. At this time, the central controller 320 or the wheel-end controller 410 receives a first brake signal. In response to the first brake signal, the brake motor 421 continues to output braking torque, causing the brake motor 421 to be locked, and the brake caliper applies a first clamping force to clamp the brake disc 440. During the time period from t0 to t1, the temperature of the brake motor 421 remains below the first temperature threshold.

[0105] Optionally, the magnitude of the braking signal received in the time period from 0 to t0 and the magnitude of the first braking signal received at time t0 may be the same as or different from each other.

[0106] At time t2, before time t3, the temperature of brake motor 421 rises to a first temperature threshold. The time period from t1 to t3 is a first predetermined duration. From this point until time t2, wheel-end controller 410 no longer controls brake motor 421 to output braking torque. Instead, it controls parking unit 430 to lock brake motor 421, maintaining brake caliper 422 in a fixed clamping position. Subsequently, after time t2, the temperature of brake motor 421 begins to decrease.

[0107] like Figure 12 As shown in (2), during the time period from t1 to t3 (i.e., the first preset time duration), the central controller 320 or the wheel-end controller 410 receives a first braking signal. In response to the first braking signal, the brake motor 421 continuously outputs a braking torque, and the brake caliper 422 continuously outputs a first clamping force to clamp the brake disc 440. The temperature of the brake motor 421 is always maintained within the first temperature threshold.

[0108] At time t3 , the wheel end controller 410 no longer controls the brake motor 421 to output the braking torque, but controls the parking unit 430 to lock the brake motor 421 so that the brake caliper 422 remains in a fixed clamping position.

[0109] For example, Figure 13 FIG. 1 shows another control process diagram provided by an embodiment of the present application. Figure 13 As shown in (1), the time period from t1 to t3 is the first preset time length. At time t4 before time t3, due to the driver increasing the pedal pressure or the AVH triggering the anti-slope function, the brake signal received by the central controller 320 or the wheel end controller 410 becomes larger (the increased brake signal is the second brake signal). In response to the second brake signal, the braking torque continuously output by the brake motor 421 increases, and the clamping force continuously output by the brake caliper 422 (i.e., the second clamping force) also increases. The temperature of the brake motor 421 continues to rise.

[0110] At time t5, before time t6, the temperature of brake motor 421 rises to a first temperature threshold. The time period from t4 to t6 is a second predetermined duration. From this point until time t5, wheel-end controller 410 no longer controls brake motor 421 to output braking torque. Instead, it controls parking unit 430 to lock brake motor 421, maintaining brake caliper 422 in a fixed clamping position. Subsequently, after time t5, the temperature of brake motor 421 stops rising or begins to decrease.

[0111] like Figure 13 As shown in (2), during the time period from t4 to t6 (i.e., the second preset time duration), the central controller 320 or the wheel-end controller 410 receives the second braking signal. In response to the second braking signal, the brake motor 421 continuously outputs the braking torque, and the brake caliper 422 continuously outputs the second clamping force to clamp the brake disc 440. The temperature of the brake motor 421 is always maintained within the first temperature threshold.

[0112] At time t6 , the wheel end controller 410 no longer controls the brake motor 421 to output the braking torque, but controls the parking unit 430 to lock the brake motor 421 so that the brake caliper 422 remains in a fixed clamping position.

[0113] about Figure 13 For information on other time periods, please refer to Figure 12 An introduction to the corresponding time period is shown.

[0114] It is understood that the above embodiment describes the control process of the wheel-end controller 410. Optionally, the above control process may also be executed by the central controller 320.

[0115] In some embodiments, after the vehicle brakes until its speed decelerates to zero, the central controller 320 may continue to receive the first braking signal. In response to the first braking signal, the central controller 320 controls the wheel-end brake device 310 to continue outputting the first clamping force for a first preset duration. Specifically, the central controller 320 may output a braking torque signal to the wheel-end controller 410 based on the first braking signal. The wheel-end controller 410 controls the brake motor 421 to output the braking torque indicated by the braking torque signal based on the braking torque signal. The braking torque may drive the brake caliper 422 to output the first clamping force to the vehicle's brake disc 440.

[0116] Optionally, in this embodiment, the first braking signal may be at least one of a pedal travel signal, a braking signal of an AVH system, a braking signal of an intelligent driving system, a braking signal of a vehicle body stability system, and the like.

[0117] In this embodiment, as a possible implementation, while the wheel-end braking device 310 continues to output the first clamping force for a first preset time period, in response to the temperature of the brake motor 421 being greater than or equal to the first temperature threshold, or the single board temperature of the wheel-end controller 410 being greater than or equal to the second temperature threshold, the wheel-end braking device 310 is controlled to lock the brake motor 421.

[0118] As another possible implementation, while the wheel-end brake device 310 continues to output the first clamping force, the central controller 320 responds to the fact that the temperature of the brake motor 421 is less than the first temperature threshold and the single board temperature of the wheel-end controller 410 is less than the second temperature threshold. It first controls the wheel-end brake device 310 to output the first clamping force for a first preset time period, and then controls the wheel-end brake device 310 to lock the brake motor 421.

[0119] In some embodiments, while the central controller 320 controls the wheel-end brake device 310 to output the first clamping force for a first preset duration, in response to the second braking signal, the central controller 320 controls the wheel-end brake device 310 to output the second clamping force for a second preset duration. The second clamping force is the clamping force indicated by the second braking signal.

[0120] Similarly, during the process in which the central controller 320 controls the wheel-end brake device 310 to output the first clamping force for a second preset duration, in response to the temperature of the brake motor 421 being greater than or equal to the first temperature threshold, or the temperature of the single board of the wheel-end controller 410 being greater than or equal to the second temperature threshold, the wheel-end brake device 310 is controlled to lock the brake motor 421. Alternatively, in response to the temperature of the brake motor 421 being less than the first temperature threshold and the temperature of the single board of the wheel-end controller 410 being less than the second temperature threshold, the wheel-end brake device 310 may be first controlled to output the second clamping force for a second preset duration, and then the wheel-end brake device 310 may be controlled to lock the brake motor 421.

[0121] For other implementations of the central controller 320 , reference may be made to the similar implementations of the aforementioned wheel-end controller 410 .

[0122] For example, Figure 14 The figure shows a flow chart of a parking method provided by an embodiment of the present application. Optionally, the method can be executed by a wheel-end controller or a central controller. Figure 14 As shown, the method includes the following steps:

[0123] S1401: Obtain a braking signal.

[0124] Optionally, the brake signal can be one or more of a pedal travel signal generated by the driver continuously depressing the pedal, a brake signal from the AVH system, a brake signal from the intelligent driving system, and a brake signal from the vehicle stability system. It can also be a brake signal requested after the driver releases the pedal and the AVH system takes over. In other words, the brake signal can include one or more different types of brake signals. This ensures that switching between brake motor braking and parking unit locking can be achieved in all scenarios where different entities request braking, reducing the probability of brake loss due to excessive brake motor temperature and improving vehicle braking safety.

[0125] S1402. Control the brake motor to output a clamping force indicated by a brake signal.

[0126] Optionally, when the central controller executes the control process, the central controller can send a braking torque signal obtained based on the braking signal to the wheel-end controller, and the wheel-end controller controls the brake motor to output the clamping force indicated by the braking signal based on the braking torque signal.

[0127] S1403: Determine whether the vehicle is stationary.

[0128] For example, whether the vehicle is stationary can be determined based on the vehicle's wheel speed, vehicle speed, etc. For example, when the vehicle's wheel speed or vehicle speed is zero, it can be determined that the vehicle is stationary.

[0129] S1404: Determine whether the duration for which the vehicle remains stationary is greater than or equal to a third preset duration.

[0130] If yes, then execute step S1405. If no, then end or return to execute step S1401. Exemplarily, the third preset time length may be 1 minute.

[0131] S1405: Determine the holding time and start the countdown for the holding time.

[0132] The holding time may be the first preset time as described above. In some embodiments, the holding time may be determined based on one or more of the clamping force currently output by the brake caliper (or the clamping force indicated by the current brake signal, or the braking torque currently output by the brake motor), the road slope on which the vehicle is located, etc. Optionally, the clamping force currently output by the brake caliper may be based on Figure 4 The clamping force sensor shown in the figure obtains that the clamping force currently output by the brake caliper may be the clamping force when the vehicle is stationary for a period of time that satisfies a third preset period of time.

[0133] Optionally, when the vehicles are on the same road slope, different clamping forces correspond to different holding times, or different clamping force ranges correspond to different holding times.

[0134] S1406: Determine whether the brake signal has changed (or determine whether the clamping force output by the brake caliper has changed).

[0135] If yes, the process returns to step S1405. If no, the process returns to step S1407.

[0136] Similarly, when the brake signal changes, the hold time can be re-determined. Optionally, when re-determining the hold time, in addition to re-determining the hold time based on one or more of the clamping force indicated by the changed brake signal, the road slope on which the vehicle is located, etc., since the brake motor has been continuously outputting braking torque for a period of time, the hold time can also be re-determined based on the clamping force before the change, the duration of the brake motor's continuous output of braking torque, etc. This can make the determined hold time more accurate.

[0137] S1407: Determine whether the temperature of the brake motor is greater than or equal to a first temperature threshold, and whether the temperature of the board of the wheel-end controller is greater than or equal to a second temperature threshold.

[0138] If the temperature of the brake motor is greater than or equal to the first temperature threshold, or the temperature of the wheel-end controller board is greater than or equal to the second temperature threshold, during the holding time, step S1409 is executed. If the temperature of the brake motor remains less than the first temperature threshold, and the temperature of the wheel-end controller board remains less than the second temperature threshold, step S1408 is executed.

[0139] S1408: Determine whether the hold time is 0.

[0140] If yes, execute step S1409. If no, return to execute step S1405.

[0141] S1409: Control the parking unit to lock the brake motor.

[0142] The above is only a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present application shall be included in the scope of protection of the present application. Therefore, the scope of protection of the present application shall be based on the scope of protection of the claims.

Claims

1. A wheel end brake device for a vehicle, characterized in that: The wheel-end braking device includes a braking unit, a parking unit, and a wheel-end controller. The braking unit includes a brake motor and a brake caliper. The brake motor is used to output a braking torque to drive the brake caliper to output a clamping force to the brake disc of the vehicle. The parking unit is used to lock the brake motor. After the vehicle is braked until the vehicle speed is reduced to zero, the wheel-end controller is used to: While the brake unit continues to output the first clamping force for a first preset period of time, in response to the temperature of the brake motor being greater than or equal to a first temperature threshold or the single board temperature of the wheel end controller being greater than or equal to a second temperature threshold, the parking unit is controlled to lock the brake motor.

2. The wheel end brake device according to claim 1, characterized in that: After the vehicle speed is reduced to zero, while the brake unit continues to output the first clamping force, the wheel end controller is further configured to: In response to the temperature of the brake motor being lower than the first temperature threshold and the temperature of the board of the wheel-end controller being lower than the second temperature threshold, the brake unit is controlled to output the first clamping force for the first preset time period.

3. The wheel end brake device according to claim 2, characterized in that: After the vehicle is braked until the speed of the vehicle is reduced to zero, the wheel-end controller is further configured to: In response to the brake unit continuing to output the first clamping force for the first preset time period, the parking unit is controlled to lock the brake motor.

4. The wheel end brake device according to claim 1, characterized in that: The first clamping force is the clamping force indicated by the first braking signal. After the vehicle is braked until the vehicle speed is reduced to zero, the wheel-end controller is further configured to: During the process of controlling the braking unit to output the first clamping force for the first preset time period, in response to a second braking signal, the braking unit is controlled to output a second clamping force for a second preset time period, wherein the second clamping force is the clamping force indicated by the second braking signal, and the second preset time period is different from the first preset time period.

5. The wheel end brake device according to claim 4, characterized in that: After the vehicle is braked until the vehicle speed is reduced to zero, the wheel-end controller is used to: During the process of controlling the brake unit to output the second clamping force for the second preset time period, in response to the temperature of the brake motor being greater than or equal to the first temperature threshold or the single board temperature of the wheel end controller being greater than or equal to the second temperature threshold, the parking unit is controlled to lock the brake motor.

6. The wheel end brake device according to claim 4, characterized in that: After the vehicle is braked until the vehicle speed is reduced to zero, in the process of receiving the second braking signal, the wheel end controller is configured to: In response to the temperature of the brake motor being lower than the first temperature threshold and the single board temperature of the wheel end controller being lower than the second temperature threshold, the brake unit is first controlled to output the second clamping force for the second preset time, and then the parking unit is controlled to lock the brake motor.

7. The wheel end brake device according to any one of claims 4 to 6, characterized in that: The second clamping force is greater than the first clamping force, and the second preset time length is less than the first preset time length.

8. The wheel end brake device according to any one of claims 4 to 7, characterized in that: The first preset time length is negatively correlated with the slope of the road on which the vehicle is located, and the second preset time length is negatively correlated with the slope of the road on which the vehicle is located.

9. The wheel end brake device according to claim 1, characterized in that: After the vehicle is braked until the speed of the vehicle is reduced to zero and the speed remains zero for a third preset time period, the wheel-end controller is configured to: During the process in which the brake unit continues to output the first clamping force for the first preset time period, in response to the temperature of the brake motor being greater than or equal to the first temperature threshold or the temperature of the single board of the wheel end controller being greater than or equal to the second temperature threshold, controlling the parking unit to lock the brake motor; or In response to the brake unit continuing to output the first clamping force for the first preset time period, the parking unit is controlled to lock the brake motor.

10. The wheel end brake device according to claim 1, characterized in that: After controlling the parking unit to lock the brake motor, the wheel end controller is further configured to: In response to an accelerator signal, the parking unit is controlled to unlock the brake motor.

11. The wheel end brake device according to any one of claims 1 to 10, characterized in that: The wheel end controller includes a control circuit, a brake motor power circuit and a parking motor power circuit, and the parking unit includes a parking motor, wherein: The brake motor power circuit includes a three-phase bridge arm, and the midpoint of the three-phase bridge arm of the brake motor power circuit is used to connect the three-phase winding of the brake motor; The parking motor power circuit includes a three-phase bridge arm, and the midpoint of the three-phase bridge arm of the parking motor power circuit is used to connect the three-phase winding of the parking motor; The control circuit is used to receive a braking signal and control the midpoint of the three-phase bridge arm of the brake motor power circuit to output a braking motor driving current or control the midpoint of the three-phase bridge arm of the parking motor power circuit to output a parking motor driving current.

12. A braking system with a parking function for a vehicle, characterized in that: The braking system includes four wheel-end braking devices and a central controller. The wheel-end braking devices include a braking unit, a parking unit, and a wheel-end controller. The braking unit includes a brake motor and a brake caliper. The brake motor is used to output a braking torque to drive the brake caliper to output a clamping force to the brake disc of the vehicle. The parking unit is used to lock the brake motor. After the vehicle is braked until the speed of the vehicle is reduced to zero, the central controller is configured to: While the wheel-end braking device continues to output the first clamping force for a first preset period of time, in response to the temperature of the brake motor being greater than or equal to a first temperature threshold, or the single board temperature of the wheel-end controller being greater than or equal to a second temperature threshold, the wheel-end braking device is controlled to lock the brake motor.

13. The braking system according to claim 12, characterized in that After the vehicle is braked until the speed of the vehicle is reduced to zero, while the wheel-end brake device continues to output the first clamping force, the central controller is further configured to: In response to the temperature of the brake motor being lower than the first temperature threshold and the single board temperature of the wheel-end controller being lower than the second temperature threshold, the wheel-end brake device is first controlled to output the first clamping force for the first preset time period, and then the wheel-end brake device is controlled to lock the brake motor.

14. The braking system according to claim 12, wherein: The first clamping force is the clamping force indicated by the first brake signal. After the vehicle is braked until the speed of the vehicle is reduced to zero, the central controller is further configured to: In the process of controlling the wheel-end braking device to output the first clamping force for the first preset time, in response to the second braking signal, the wheel-end braking device is controlled to output the second clamping force for the second preset time, the second clamping force is the clamping force indicated by the second braking signal, the second clamping force is greater than the first clamping force, and the second preset time is less than the first preset time.

15. A vehicle, characterized in that: The invention comprises the wheel end braking device according to any one of claims 1 to 11, or comprises the braking system according to any one of claims 12 to 14.

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