Electric vehicle wet brake axle wheel rim temperature cooperative protection system and method

Abstract

The invention discloses an electric vehicle wet brake axle wheel temperature cooperative protection system and method, and relates to the technical field of pure electric and hybrid vehicle wet brake control, and the system comprises a temperature sensor, a VCU, an early warning device, an MCU, a driving motor, an alarm device and a wet brake axle. The temperature sensors are arranged in oil cavities of the four wheel edge wet type brakes and collect the oil temperature in real time. The VCU compares the oil temperature with a preset first-level alarm threshold value, a preset speed-limiting protection threshold value and a preset shutdown protection threshold value; when the oil temperature reaches the alarm threshold value, early warning is triggered; when the speed limit threshold value is reached, motor output is limited; when a shutdown threshold value is reached, the motor is controlled to stop; and the limitation is automatically relieved after the oil temperature of all the wheel edges falls back to the safety range. Accurate monitoring and graded active protection of the temperature of the wheel rim are achieved, overheating failure of the wet brake bridge is effectively prevented, the driving safety of a vehicle under the working conditions of heavy load, long downhill and the like is remarkably improved, and the service life of a brake system is prolonged.

Description

Technical Field

[0001] This invention relates to the field of braking control technology for pure electric and hybrid vehicles, specifically to a system and method for coordinated protection of wheel-side temperature of wet brake axles for electric vehicles, which is particularly applicable to pure electric and hybrid vehicles such as construction machinery, heavy trucks, and mining vehicles that use wet brake axles. Background Technology

[0002] Wet brake axles are widely used in engineering vehicles and heavy-duty vehicles due to their excellent sealing, long lifespan, and maintenance-free operation. Pure electric and hybrid vehicles are directly driven by electric motors, featuring high torque, fast response, and high transmission efficiency. However, under conditions such as frequent braking, long downhill slopes, heavy loads, and prolonged high-speed travel during site transfers, the continuous friction of the wet brake pads generates a significant amount of heat. Wet brake axles rely on oil circulation for cooling. Although the main reduction axle housing is connected to the wheel wells, the housing itself is on the windward side of the vehicle, resulting in a relatively low oil temperature. Furthermore, the wheel well assemblies are poorly cooled during driving due to tire obstruction, leading to relatively high oil temperatures at the wheel wells. Some low-speed engineering vehicles require prolonged high-speed travel during site transfers, which can also cause the drive axle oil temperature to rise, potentially damaging internal seals and causing drive axle failure. In summary, the existing technology has the following problems:

[0003] 1. Lack of real-time, accurate monitoring and coordinated judgment of oil temperature at individual wheel edges.

[0004] 2. When the oil temperature rises abnormally at one wheel of the vehicle due to frequent braking, poor oil flow, or other reasons, there is a lack of effective early warning and proactive intervention mechanisms.

[0005] 3. Sustained high temperatures can cause brake fluid performance to deteriorate, viscosity to decrease, oxidation to occur, air bubbles to form, seals to age and fail, and friction pads to burn out, ultimately leading to a decline in braking performance or even complete failure, posing a serious safety hazard.

[0006] 4. Traditional temperature protection may only focus on a single temperature point or the axle coil temperature, and cannot accurately reflect local overheating at the wheel edge. Summary of the Invention

[0007] This invention aims to provide a coordinated protection system and method for wheel-side temperature of wet brake axles in electric vehicles. By independently and in real-time monitoring the oil temperature of the four wheel-side brakes and setting multiple temperature thresholds, the system achieves coordinated control by providing intelligent early warning when the oil temperature exceeds the limit, actively limiting the motor output power until the motor stops to dissipate heat, and automatically releasing the limit after all wheel-side temperatures return to normal. This effectively prevents brake overheating failure, improves driving safety, and extends the service life of wet brake axles.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A wet brake axle wheel-side temperature collaborative protection system for electric vehicles includes: multiple wheel-side temperature sensors, a vehicle control unit (VCU), a motor controller (MCU), a drive motor, and a warning alarm device.

[0010] The multiple wheel-side temperature sensors are respectively installed on multiple wheel-side wet brakes of the vehicle to collect the oil temperature of each wheel-side wet brake in real time.

[0011] The vehicle control unit (VCU) is connected to the temperature sensors at each wheel end to receive and process the oil temperature signals at each wheel end, and to generate control commands based on a preset collaborative protection logic.

[0012] The motor controller MCU is connected to the VCU and is used to receive motor control commands sent by the VCU;

[0013] The drive motor is connected to the MCU, and its output is controlled by the MCU.

[0014] The early warning and alarm device is connected to the VCU and is used to receive instructions from the VCU and issue early warning and / or alarm signals.

[0015] The VCU independently or in combination controls the operation of the early warning alarm device and limits the output of the drive motor based on the collaborative comparison results of all wheel-side oil temperatures and preset multi-level temperature thresholds.

[0016] Furthermore, there are four wheel-side wet brakes, corresponding to the left front wheel, right front wheel, left rear wheel, and right rear wheel of the vehicle; the wheel-side temperature sensors are respectively installed inside the oil chamber of each wheel-side wet brake or in the oil circuit near the friction pair.

[0017] Furthermore, the VCU specifically includes:

[0018] The signal acquisition module is used to cyclically read the real-time oil temperature data collected by the temperature sensors on each wheel side;

[0019] The temperature processing module is used to filter and calibrate the received oil temperature data.

[0020] The logic judgment module is used to compare the processed oil temperature of each wheel edge with multiple preset temperature thresholds and execute the core control logic of collaborative protection.

[0021] An alarm output module is used to generate and send a first-level early warning command and / or a second-level alarm command to the early warning alarm device based on the judgment result of the logic judgment module.

[0022] The motor control command output module is used to generate and send commands to the motor controller MCU to limit or release the motor speed and / or torque based on the judgment result of the logic judgment module.

[0023] Furthermore, the early warning alarm device includes:

[0024] A level-one early warning device is used to receive the level-one early warning command from the VCU and issue an early warning prompt; and,

[0025] A secondary alarm device is used to receive the secondary alarm command from the VCU and issue an alarm prompt.

[0026] Furthermore, the system also includes a data storage module connected to the VCU for recording and storing temperature data, early warning events, alarm events, and speed limit events.

[0027] A method for coordinated protection of wheel-side temperature of wet brake axles in electric vehicles, applied to the aforementioned coordinated protection system, includes the following steps:

[0028] Step 1: After the vehicle starts, collect and process the real-time oil temperature T_current of all wheel-side wet brakes.

[0029] Step 2: Set three temperature thresholds, including: a level 1 alarm threshold T_warn, a speed limit protection threshold T_protect, and a shutdown protection threshold T_limit, and satisfy T_limit > T_protect > T_warn;

[0030] Step 3: Based on the comparison results of the real-time oil temperature of all wheel edges with the three-level temperature threshold, perform coordinated protection control. The coordinated protection control will trigger the corresponding protection if any wheel edge exceeds the temperature, and will only release the protection when all wheel edges meet the safety conditions.

[0031] Furthermore, step 3 specifically includes:

[0032] Shutdown protection judgment: If the real-time oil temperature T_current ≥ T_limit of any wheel side, the VCU control will trigger a level 2 alarm and control the drive motor to stop.

[0033] Speed ​​limit protection judgment: If T_limint ≥ real-time oil temperature of any wheel side, T_current ≥ T_protect, then the VCU control triggers a first-level warning and limits the speed and / or torque of the drive motor;

[0034] Level 1 warning judgment: If T_protect ≥ real-time oil temperature of any wheel side, and T_current ≥ T_warn, then the VCU will only control and trigger the Level 1 warning, without limiting the motor;

[0035] Safety status assessment: If T_current < T_warn for all wheel sides, then the VCU control will remove all warnings and restrictions, and the vehicle will resume normal operation.

[0036] Furthermore, the methods for limiting the speed and / or torque of the drive motor include any one or a combination of the following:

[0037] Limit it to a fixed value, such as a certain percentage of the current highest speed or torque;

[0038] Classified restrictions are implemented based on the number of overheating wheel edges or the highest temperature value;

[0039] The speed limit is proportionally limited based on the difference between the real-time oil temperature and the speed limit protection threshold T_protect.

[0040] Furthermore, the triggering of the secondary alarm also includes: the VCU sending a command to the secondary alarm device to remind the driver that the wheel-side temperature is too high and the vehicle will stop.

[0041] Furthermore, the control of stopping the drive motor specifically includes:

[0042] If the drive motor is running, the MCU controls it to gradually decelerate to a stop within a set time.

[0043] If the drive motor is not running, the MCU controls it to remain in a non-started state.

[0044] Furthermore, the collaborative protection control also includes a release judgment logic:

[0045] Level 2 alarm clearance conditions: The drive motor has stopped, or the real-time oil temperature T_current < T_limit on all wheel sides;

[0046] Speed ​​limit protection release condition: Real-time oil temperature T_current < T_protect - n℃ for all wheel sides, where n is the preset hysteresis temperature value;

[0047] Level 1 warning cancellation condition: The real-time oil temperature T_current of all wheel sides < T_warn - n℃, where n is the preset hysteresis temperature value.

[0048] Furthermore, the preset hysteresis temperature value n ranges from 3°C to 5°C.

[0049] Furthermore, the method is continuously and cyclically executed after the vehicle is started.

[0050] The beneficial effects of this invention are:

[0051] 1. Active safety protection: By monitoring in real time and actively limiting power output, it effectively prevents brake failure caused by overheating of wet brake axles, greatly improving vehicle driving safety, especially suitable for harsh working conditions such as heavy loads and long downhill slopes.

[0052] 2. Precise problem location: Wheel edge monitoring can quickly locate the specific wheel edge that is overheating, which facilitates subsequent maintenance.

[0053] 3. Protect core components: Prevent brake fluid from deteriorating at high temperatures, seals from being damaged, and friction pads from burning, significantly extending the service life of wet brake axles and reducing maintenance costs.

[0054] 4. Intelligent collaborative control: Based on the collaborative judgment logic of multi-round edge temperature information, any trigger protection will be released only when all are safe, ensuring precise and reliable control.

[0055] 5. Two-level early warning and one-level protection mechanism: The early warning threshold provides early warning, the protection threshold triggers substantial intervention, and the final protection mechanism stops the entire vehicle, balancing safety and ease of operation.

[0056] 6. Applicable to pure electric and hybrid platforms: Fully utilizes the advantage of fast motor control response to achieve active thermal protection that is difficult to achieve in traditional mechanical or hydraulic braking vehicles.

[0057] 7. Enhance user experience: Clear audible and visual alarms allow drivers to be aware of the vehicle's status in a timely manner and take appropriate measures, such as finding a safe place to park and allow the vehicle to cool down. Attached Figure Description

[0058] Figure 1 : Block diagram of the protection system structure described in this invention;

[0059] Figure 2 : A control unit composition diagram of the VCU described in this invention;

[0060] Figure 3 : A logic diagram of the protection method described in this invention;

[0061] Figure 4 : Flowchart of the protection method described in this invention. Detailed Implementation

[0062] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments and specific features in the embodiments are detailed descriptions of the technical solution of the present application, rather than limitations thereof. In the absence of conflict, the embodiments and technical features in the embodiments can be combined with each other.

[0063] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0064] like Figure 1 As shown, this application provides a wet brake axle wheel-side temperature coordinated protection system for electric vehicles. The system mainly includes: a temperature sensor, a vehicle control unit (VCU) 2, a primary warning device 3, a motor controller (MCU) 4, a drive motor 5, a secondary alarm device 6, a transmission device 7, a wet brake axle 8, and a data storage module 9. The temperature sensor is connected to the vehicle control unit (VCU) 2 via a CAN cable or other wireless means to transmit signals. The vehicle control unit (VCU) 2 is connected to the primary warning device 3, the motor controller (MCU) 4, the secondary alarm device 6, and the data storage module 9 via CAN or other wireless means to transmit signals. The motor controller (MCU) 4 is connected to the drive motor 5 via CAN or other wireless means to transmit signals. The drive motor 5 is connected to the wet brake axle 8 via the transmission device 7 to transmit speed and torque.

[0065] The wet brake axle 8 includes four wet brakes, which are the braking actuators of the vehicle. They include brakes, oil chambers and related oil circuits to realize the braking of the drive axle; they are the left front wheel wet brake 8a, the right front wheel wet brake 8b, the left rear wheel wet brake 8c, and the right rear wheel wet brake 8d.

[0066] The temperature sensors include a left front wheel temperature sensor 1a, a right front wheel temperature sensor 1b, a left rear wheel temperature sensor 1c, and a right rear wheel temperature sensor 1d installed in the oil chambers or oil circuits near the friction pairs of the wet brakes (8a, 8b, 8c, 8d) on the four wheels of the vehicle, for real-time monitoring of the oil temperature at the brake pistons on each wheel.

[0067] The vehicle control unit (VCU) 2 includes a signal acquisition module 2a for cyclically reading real-time oil temperature data collected by each wheel-side temperature sensor; a temperature processing module 2b for filtering and calibrating the received oil temperature data; a logic judgment module 2c for comparing the processed oil temperature at each wheel-side with multiple preset temperature thresholds and executing the core control logic for coordinated protection; an alarm output module 2d for generating and sending a first-level warning command and / or a second-level alarm command to the warning alarm device based on the judgment result of the logic judgment module; and a motor control command output module 2e for generating and sending commands to limit or release the motor speed and / or torque to the motor controller MCU based on the judgment result of the logic judgment module. Figure 2 As shown.

[0068] The first-level warning device 3 is used to receive warning commands from the VCU and issue a first-level warning. One warning method is to illuminate the instrument panel icon; other icons are displayed or flashing, indicating to the driver that the oil temperature at the wheel side is too high, thus providing an early warning.

[0069] The motor controller MCU 4 is used to receive motor control commands from the VCU and to actually control the output speed and / or torque of the drive motor.

[0070] Drive motor 5 is used as the power source for the vehicle, and its output is controlled by the MCU.

[0071] The secondary alarm device 6 receives the alarm command from the VCU and performs a secondary alarm. One alarm mode is the display of the instrument panel icon; another alarm mode is the sound mode of the buzzer; and a third alarm mode is a combination of sound and light, which prompts the driver that the wheel side temperature is too high and that the vehicle needs to stop.

[0072] Transmission device 7, a transmission device consisting of a gearbox and a drive shaft; or a transmission device consisting of only a drive shaft; or a device of other types capable of transmitting speed and torque.

[0073] Data storage module 9: Records temperature data, alarm events, speed limit events, etc., for fault diagnosis and analysis.

[0074] like Figure 3As shown, this application also provides a method for coordinated protection of wheel-side temperature of wet brake axles in electric vehicles. This method sets three temperature thresholds for the wheel-side oil temperature of the wet brake axle: shutdown protection threshold T_limit > speed limit protection threshold T_protect > first-level alarm threshold T_warn. T_warn is used for first-level warning, T_protect is used to trigger substantive protection measures (speed limit), and T_limit is used for second-level alarm and triggers motor shutdown to prevent damage and failure of internal components of the drive axle due to high internal oil temperature. Coordinated judgment is based on the three thresholds: alarm and speed limit are triggered based on overheating of any wheel-side, and the release condition requires all wheel-sides to meet safety conditions. This ensures that even if only one wheel-side overheats, protection is provided, and the restriction is only fully released after all wheel-sides are safe, preventing premature protection exit. The specific judgment for protection control is as follows: If T_protect ≥ any wheel-side oil temperature and T_current ≥ T_warn, only a first-level warning is issued, and speed is not limited; if T_limit ≥ any wheel-side oil temperature and T_current ≥ T_protect, both a first-level warning and speed limitation are issued; if any wheel-side oil temperature and T_current ≥ T_limit, a second-level alarm is issued, and the motor cannot start or the motor will gradually decelerate and stop. The specific judgment for protection limit release is as follows: Second-level alarm release condition: the entire machine stops, or all wheel-side oil temperatures T_current < T_limit; Speed ​​limitation release condition: all wheel-side oil temperatures T_current < T_protect - n℃ (n is the set temperature value); First-level warning release condition: all wheel-side oil temperatures T_current < T_warn - n, or the second-level alarm is activated / retained.

[0075] like Figure 4 As shown, the specific steps of this protection method are as follows:

[0076] Step S200: Start-up of the entire machine

[0077] Step S201: Real-time temperature acquisition and processing. The VCU continuously reads and processes the real-time oil temperature T_current data (T1, T2, T3, T4) from the four wheel-side temperature sensors.

[0078] Step S202: Monitor oil temperature and determine the shutdown protection threshold. The VCU determines whether the real-time oil temperature T_current of all wheel sides is less than the preset shutdown protection threshold T_limit.

[0079] 1. No (S202-N): Proceed to step S204 to activate the secondary alarm device: VCU sends a command to the secondary alarm device 6 to activate the secondary alarm device (e.g., prompting the driver "High wheel edge temperature, stop the vehicle, please pay attention"); simultaneously proceed to step S220 to stop the vehicle: VCU 2 sends a command to MCU 4 to monitor the operating status of drive motor 5: 1) Drive motor 5 is running, MCU 4 controls drive motor 5 to stop running within a certain period of time, triggering step S212 to deactivate the secondary alarm device: After drive motor 5 stops running, VCU 2 sends a command to the secondary alarm device 6 to deactivate the secondary alarm device; 2) Drive motor 5 is not running, MCU 4 controls drive motor 5 not to start, activating step S212.

[0080] 2. Yes (S202-Y): Proceed to step S203, and simultaneously activate step S212 to deactivate the secondary alarm device.

[0081] Step S203: Monitor oil temperature and determine the speed limit protection threshold. The VCU determines whether the real-time oil temperature T_current of all wheel sides is less than or equal to the preset speed limit protection threshold T_protect.

[0082] 1. No (S203-N): Proceed to step S205 (Activate / Maintain Speed ​​Limit):

[0083] 1) Operation method: VCU 2 sends a command to MCU 4 to limit the maximum permissible speed N_max and / or maximum permissible torque Tq_max of the drive motor 5. The degree of limitation includes any one or a combination of the following:

[0084] i. Fixed value (e.g., limited to 70% of the current maximum speed).

[0085] ii. Classification restrictions are applied based on the number of overheated wheel edges or the highest temperature value (the higher the temperature, the stricter the restriction).

[0086] iii. Limit the ratio based on the difference between the temperature and T_protect.

[0087] 2) Initial activation: As long as the oil temperature T_current ≥ T_protect at any wheel edge, the speed / torque limiting state is maintained;

[0088] 3) Limitation state maintenance: T_current ≥ T_protect – n℃. (n is the set temperature value, which can be 3~5℃).

[0089] 4) Purpose: To reduce the output power of the motor, reduce the kinetic energy input of the vehicle, thereby reducing the load on the brakes and promoting heat dissipation and cooling of the wheel side.

[0090] 2. Yes (S203-Y): Proceed to step S206.

[0091] Step S206: Monitor oil temperature and determine if the speed limiter is released. VCU 2 determines that the real-time oil temperature T_current at all wheel sides is less than the preset alarm threshold T_protect-n℃ (n is the set temperature value, which can be 3~5℃):

[0092] 1. No (S206-N): Return to step S205 (Activate / Hold the motor speed limit).

[0093] 2. Yes (S206-Y): Proceed to step S207 (Do not / Remove motor speed limit and / or torque limit).

[0094] Step S207: Do not / release motor speed and / or torque limiting

[0095] VCU 2 sends a command to MCU 4 to remove the speed / torque limit on drive motor 5, allowing drive motor 5 to return to its maximum output capacity under normal conditions; activate step S208.

[0096] Step S208: Monitor oil temperature and determine whether the real-time oil temperature T_current of all wheel sides is less than the preset first-level alarm threshold T_warn by the VCU.

[0097] 1. No (S208-N): Proceed to step S209 (Activate / Maintain Level 1 Warning Device Warning): 1) Initial activation: VCU2 sends a warning command to Level 1 Warning Device 3 (e.g., prompting the driver "High wheel edge temperature, please pay attention"); 2) Status maintenance: All wheel edge temperatures T_current≥T_warn-n℃ (n is the set temperature value, which can be 3~5℃); 3) Status compatibility: Even if the speed limit state is subsequently entered, the warning usually continues or changes its form (e.g., the flashing frequency increases); 4) Activate step S203 speed limit protection threshold judgment.

[0098] 2. Yes (S208-Y): Proceed to step S210 (monitor oil temperature, first-level warning cancellation judgment).

[0099] Step S210: Monitor oil temperature and determine if the first-level warning is lifted.

[0100] VCU 2 determines that the real-time oil temperature T_current at all wheel edges is less than the preset alarm threshold T_warn-n℃ (n is the set temperature value, which can be 3~5℃):

[0101] 1. No (S210-N): Return to step 209 (Activate / maintain Level 1 warning device warning).

[0102] 2. Yes (S210-Y): Proceed to step S211 (Do not activate / deactivate the first-level warning device).

[0103] Step S211: Do not activate / deactivate the Level 1 warning device.

[0104] VCU 2 sends a command to the first-level alarm device 3 to deactivate the first-level warning device.

[0105] Cyclic execution: This protection method is executed in real time and cyclically (starting from the S200 system startup).

[0106] This invention provides a coordinated control system and method for wet brake axle wheel-side temperature of electric vehicles, which has the following functions:

[0107] 1. Real-time collaborative monitoring: Independent, real-time, and accurate monitoring of the oil temperature of the four wheel-side brakes.

[0108] 2. Intelligent early warning: When the oil temperature at any one or more wheel edges exceeds the safety threshold, an alarm signal will be issued in a timely manner to remind the driver to pay attention.

[0109] 3. Active protection: When the wheel-side oil temperature reaches the high temperature threshold, the output torque or speed of the drive motor is actively limited to restrict the power input, reduce the braking load, and suppress the further increase of the wheel-side oil temperature; when the wheel-side oil temperature reaches the parking threshold, the output torque or speed of the drive motor is actively limited to restrict the power input to 0, and the whole vehicle stops to dissipate heat.

[0110] 4. Collaborative Recovery: When the oil temperature of all wheel sides returns to a safe range, the limitation on motor speed / torque is automatically released, restoring the vehicle's normal power performance.

[0111] 5. Improved safety: Effectively prevents brake failure caused by overheating of wet brake axles, ensuring vehicle driving safety.

[0112] 6. Extend lifespan: Protects brake fluid, friction pads and seals, prevents the oil temperature from continuing to rise, which could lead to failure of the drive axle oil seals and accelerated wear of internal axle parts, thus extending the service life of wet brake axles.

[0113] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A wet brake axle wheel-side temperature coordinated protection system for electric vehicles, characterized in that, include: Multiple wheel-side temperature sensors, vehicle control unit (VCU), motor controller (MCU), drive motor, and warning alarm device; The multiple wheel-side temperature sensors are respectively installed on multiple wheel-side wet brakes of the vehicle to collect the oil temperature of each wheel-side wet brake in real time. The vehicle control unit (VCU) is connected to the temperature sensors at each wheel end to receive and process the oil temperature signals at each wheel end, and to generate control commands based on a preset collaborative protection logic. The motor controller MCU is connected to the VCU and is used to receive motor control commands sent by the VCU; The drive motor is connected to the MCU, and its output is controlled by the MCU. The early warning and alarm device is connected to the VCU and is used to receive instructions from the VCU and issue early warning and / or alarm signals. The VCU independently or in combination controls the operation of the early warning alarm device and limits the output of the drive motor based on the collaborative comparison results of all wheel-side oil temperatures and preset multi-level temperature thresholds.

2. The collaborative protection system according to claim 1, characterized in that, There are four wheel-side wet brakes, corresponding to the left front wheel, right front wheel, left rear wheel and right rear wheel of the vehicle; the wheel-side temperature sensors are respectively installed inside the oil chamber of each wheel-side wet brake or in the oil circuit near the friction pair.

3. The collaborative protection system according to claim 1, characterized in that, The VCU specifically includes: The signal acquisition module is used to cyclically read the real-time oil temperature data collected by the temperature sensors on each wheel side; The temperature processing module is used to filter and calibrate the received oil temperature data. The logic judgment module is used to compare the processed oil temperature of each wheel edge with multiple preset temperature thresholds and execute the core control logic of collaborative protection. An alarm output module is used to generate and send a first-level early warning command and / or a second-level alarm command to the early warning alarm device based on the judgment result of the logic judgment module. The motor control command output module is used to generate and send commands to the motor controller MCU to limit or release the motor speed and / or torque based on the judgment result of the logic judgment module.

4. The collaborative protection system according to claim 1, characterized in that, The early warning alarm device includes: A level-one early warning device is used to receive the level-one early warning command from the VCU and issue an early warning prompt; and, A secondary alarm device is used to receive the secondary alarm command from the VCU and issue an alarm prompt.

5. The collaborative protection system according to claim 1, characterized in that, The system also includes a data storage module connected to the VCU, used to record and store temperature data, early warning events, alarm events, and speed limit events.

6. A method for coordinated protection of wheel-side temperature of wet brake axle in electric vehicles, applied to the coordinated protection system described in any one of claims 1 to 5, characterized in that, Includes the following steps: Step 1: After the vehicle starts, collect and process the real-time oil temperature T_current of all wheel-side wet brakes. Step 2: Set three temperature thresholds, including: a level 1 alarm threshold T_warn, a speed limit protection threshold T_protect, and a shutdown protection threshold T_limit, and satisfy T_limit > T_protect > T_warn; Step 3: Based on the comparison results of the real-time oil temperature of all wheel edges with the three-level temperature threshold, perform coordinated protection control. The coordinated protection control will trigger the corresponding protection if any wheel edge exceeds the temperature, and will only release the protection when all wheel edges meet the safety conditions.

7. The collaborative protection method according to claim 6, characterized in that, Step 3 specifically includes: Shutdown protection judgment: If the real-time oil temperature T_current ≥ T_limit of any wheel side, the VCU control will trigger a level 2 alarm and control the drive motor to stop. Speed ​​limit protection judgment: If T_limint ≥ real-time oil temperature of any wheel side, T_current ≥ T_protect, then the VCU control triggers a first-level warning and limits the speed and / or torque of the drive motor; Level 1 warning judgment: If T_protect ≥ real-time oil temperature of any wheel side, and T_current ≥ T_warn, then the VCU will only control and trigger the Level 1 warning, without limiting the motor; Safety status assessment: If T_current < T_warn for all wheel sides, then the VCU control will remove all warnings and restrictions, and the vehicle will resume normal operation.

8. The collaborative protection method according to claim 7, characterized in that, Methods for limiting the speed and / or torque of a drive motor include any one or a combination of the following: Limit it to a fixed value, such as a certain percentage of the current highest speed or torque; Classified restrictions are implemented based on the number of overheating wheel edges or the highest temperature value; The speed limit is proportionally limited based on the difference between the real-time oil temperature and the speed limit protection threshold T_protect.

9. The collaborative protection method according to claim 7, characterized in that, The triggering of the secondary alarm also includes: the VCU sending a command to the secondary alarm device to remind the driver that the wheel-side temperature is too high and the vehicle will stop.

10. The collaborative protection method according to claim 7, characterized in that, The control of stopping the drive motor specifically includes: If the drive motor is running, the MCU controls it to gradually decelerate to a stop within a set time. If the drive motor is not running, the MCU controls it to remain in a non-started state.

11. The collaborative protection method according to claim 6 or 7, characterized in that, The collaborative protection control also includes a release judgment logic: Level 2 alarm clearance conditions: The drive motor has stopped, or the real-time oil temperature T_current < T_limit on all wheel sides; Speed ​​limit protection release condition: Real-time oil temperature T_current < T_protect - n℃ for all wheel sides, where n is the preset hysteresis temperature value; Level 1 warning cancellation condition: The real-time oil temperature T_current of all wheel sides < T_warn - n℃, where n is the preset hysteresis temperature value.

12. The collaborative protection method according to claim 11, characterized in that, The preset hysteresis temperature value n ranges from 3°C to 5°C.

13. The collaborative protection method according to claim 6, characterized in that, The method is executed continuously and cyclically after the vehicle is started.

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