Multi-mode integrated redundant driving and braking integrated electric wheel system

Abstract

The invention discloses a multi-mode integrated redundancy driving and braking integrated electric wheel system. The system comprises a hub motor, a first-stage planetary gear train, a second-stage planetary gear train, a braking system, a wheel unit and a bearing system. According to the system, two sets of planetary gear trains are used for composite transmission, and multi-mode gear shifting operation of the planetary gear trains is matched, so that the hub motor can serve as an execution motor responsible for driving work of the wheel unit and braking work of the braking system at the same time, and the system has the functions of driving, traveling braking, reversing braking and parking braking; driving and braking integrated design and control of the electric wheel system can be achieved, the energy utilization rate of the whole vehicle is improved to the maximum extent, meanwhile, due to the fact that a braking system execution motor and a speed reducer thereof are omitted, sprung mass is greatly reduced, controllability and driving comfort of the whole vehicle are improved, and cost is reduced. The electric wheel system has great significance in light weight and high integration design, in addition, the system has a redundant function in service braking and parking braking, and the safety is improved.

Description

Technical Field

[0001] The present invention relates to an integrated drive and brake electric wheel system applied to electric vehicles, and particularly to an integrated drive and brake electric wheel system that integrates a hub motor, a planetary gear train, a braking system, and a wheel unit, and has multi-mode switching and braking redundancy at the same time. Background Art

[0002] The intelligent chassis roadmap for passenger electric vehicles released in 2022 stipulates that the intelligent chassis is developing in the direction of actuator distribution and control integration, and the integrated control of drive and brake in the lateral and longitudinal directions should be achieved by 2025. For this reason, the drive system configuration is developing from centralized drive to distributed drive. A distributed drive electric vehicle is directly or indirectly driven by multiple hub motors or in-wheel motors, the transmission chain structure is shortened or even cancelled, the transmission efficiency is further improved, and the drive and braking torques of each wheel are accurately and independently controllable, which can meet the requirements of high mobility and high reliability, and is more likely to realize the complex dynamic control of the vehicle. At present, the hub motor, the braking system, and the suspension system can form a structurally compact electric wheel system through high-integration design, which is more conducive to the modular design and development of the chassis.

[0003] As the core component of the electric wheel system, how to make full and reasonable use of its functional characteristics and improve the working efficiency has become the key to determining the performance of the electric wheel system. At present, the mainstream configuration of distributed drive is to adopt an integrated design of a hub motor (IWM) + an electromechanical braking system (EMB). However, since the electromechanical braking system itself also needs to be equipped with a separate actuator motor and a reducer to work, this results in a large occupied space of the electric wheel system, which is not conducive to the vehicle layout. At the same time, the sprung mass is too large, resulting in poor driving smoothness and handling stability. In addition, with the continuous progress of hub motor technology, the actuator motor and the reducer equipped with the electromechanical braking system only work under specific braking conditions, and do not have a beneficial effect on the vehicle performance under other conditions. Instead, it increases the vehicle mass and makes the vehicle economy worse. The hub motor itself has a four-quadrant working characteristic range, that is, it can provide driving torque for vehicle drive, or provide actuating torque for each system actuator, and can also provide vehicle braking torque through electric braking. Therefore, if the hub motor can realize function switching through the coordinated cooperation with transmission components while providing torque for vehicle drive and electric braking, and act as the actuator motor of the electromechanical braking system under specific braking conditions to replace its original actuator motor, it will greatly save the in-wheel space and reduce the sprung mass, which is beneficial to achieving the design goal of integrated drive and brake in distributed drive.

[0004] At present, the in-wheel motor can achieve the electric braking function, and the electro-mechanical braking system can achieve the friction braking function. Meanwhile, the braking scenarios are diverse. How to match a suitable functional solution for the vehicle braking work through the multi-mode switching of the electric wheel system has become the research focus. At the same time, considering that when the on-vehicle power battery has a high charge, it will be charged in the form of pulses, and the charging speed is relatively slow. If a large-intensity braking work needs to be performed at this time, such as emergency braking, long-distance downhill sliding, etc., if the pure electric braking method is used, the electric energy generated by the braking energy recovery cannot be stored in time, resulting in overflow, which is not conducive to the health of the on-vehicle power battery. Therefore, for this working condition, the electro-mechanical braking system should be used for braking, and this part of the "extra energy" that cannot be recovered should be dissipated by means of friction to avoid damaging the battery life.

[0005] In addition, the "Performance Requirements and Test Methods for the By-Wire Chassis of Autonomous Passenger Vehicles" released in 2022 emphasizes that the by-wire braking system must have a backup function to ensure driving safety. Therefore, while the electric wheel system takes into account the integrated design of drive and braking, it also needs to consider the vehicle braking safety redundancy function.

[0006] In summary, the current automotive industry urgently needs an electric wheel system with a wide range of application scenarios, safety and reliability, and an integrated high-integration design of drive and braking with multi-mode switching and safety redundancy functions. Summary of the Invention

[0007] According to the background of the times, this paper designs an electric wheel system that integrates components such as in-wheel motors, planetary gear trains, braking systems, and wheel units, has multi-mode switching and braking redundancy functions, and can achieve the integration of drive and braking.

[0008] The technical solution of the present invention is: a multi-mode integrated redundant drive and brake integrated electric wheel system, which is characterized by including:

[0009] An in-wheel motor (100), which adopts a high-speed inner rotor motor, and its output end is connected to the first-stage sun gear in the first-stage planetary gear train, and is used to provide the execution torque for the drive and braking conditions of the multi-mode integrated redundant drive and brake integrated electric wheel system;

[0010] The first-stage planetary gear train (200), including a first-stage sun gear (210), a first-stage planet carrier (220), a first-stage differential ring gear (230), a same-speed coupling sleeve (240), and a first-stage shifting mechanism (250), is used to transmit the torque output by the in-wheel motor (100), and at the same time, the drive and brake integration function of the multi-mode integrated redundant drive and brake integrated electric wheel system is realized through multi-mode shifting operations;

[0011] The two-stage planetary gear train (300) includes a two-stage sun gear (310), a two-stage planet carrier (320), a two-stage ring gear (330), a differential input gear (340), a two-stage shifting mechanism (350), and a differential output gear (360). It is used to cooperate with the first-stage planetary gear train (200) to transmit the torque output by the hub motor (100), and at the same time, realize the integrated driving and braking function of the multi-mode integrated redundant drive and brake integrated electric wheel system through multi-mode shifting operations;

[0012] The braking system (400) consists of an electromechanical braking input gear (410), an electromechanical braking actuator (420), and a brake disc (430), and is used to provide the braking torque in the braking condition of the multi-mode integrated redundant drive and brake integrated electric wheel system;

[0013] The wheel unit (500) is mainly composed of four parts: a tire, a rim, a spoke, and a hub flange. It provides space for the highly integrated layout of each system inside, is used to support the vehicle load, and transmit the driving and braking torques;

[0014] The bearing system (600) includes an output end bearing (610), a two-stage ring gear bearing (620), a two-stage planet carrier bearing (630), and a two-stage sun gear bearing (640). All of them use deep groove ball bearings, which are used for the support of each transmission component in the first-stage planetary gear train (200) and the second-stage planetary gear train (300). At the same time, they reduce mechanical friction and improve the transmission efficiency and motion accuracy.

[0015] Preferably, the first-stage planetary gear train (200) is characterized in that it includes:

[0016] The first-stage sun gear (210) is connected to the output end of the hub motor (100) through a spline at the shaft end, and is used to transmit the torque of the hub motor (100);

[0017] The first-stage planet carrier (220) is connected to the first-stage sun gear (210) through first-stage planet gears on the inner side. There is a spline connection at the shaft end and a spline hub on the outer ring;

[0018] The first-stage differential ring gear (230) is connected to the outer side of the first-stage planet carrier (220) at one end, and is connected to the differential input gear and the differential output gear of the second-stage planetary gear train (300) at the other end to form a differential structure. There are spline hubs at both ends;

[0019] The same-speed engagement sleeve (240) is not fixedly connected to the first-stage shifting mechanism of the first-stage planetary gear train (200) and can slide relative to it. During multi-mode shifting, it can be connected to the spline hub of the first-stage planet carrier (220) and the spline hub of the first-stage differential ring gear (230), causing the first-stage planet carrier (220) and the first-stage differential ring gear (230) to rotate at the same speed and in the same direction. When disengaged, they can rotate at different speeds and in different directions.

[0020] The first-stage shifting mechanism (250) mainly consists of a first-stage shifting motor, a fork, a locking engagement sleeve, and a first-stage shifting mechanism housing. The position of the first-stage shifting mechanism housing itself remains unchanged and is stationary relative to the multi-mode integrated redundant drive and brake integrated electric wheel system. The first-stage shifting motor controls the fork and the locking engagement sleeve to perform shifting operations respectively. The first-stage shifting motor has a total of four gears: 1, 2, 3, and 4. Two gears are executed each time. Among them, gears 1 and 2 are mutually exclusive and control the left and right movement of the fork respectively, thereby driving the same-speed engagement sleeve (240) to connect or disengage from the spline hub of the first-stage planet carrier (220) and the spline hub of the first-stage differential ring gear (230). Gears 3 and 4 are mutually exclusive and control the left and right movement of the locking engagement sleeve respectively, thereby locking and connecting or disengaging from the spline hub of the second-stage planet carrier of the second-stage planetary gear train (300).

[0021] Preferably, the second-stage planetary gear train (300) is characterized in that it includes:

[0022] The second-stage sun gear (310) has its shaft end connected to the first-stage planet carrier (220) through splines to transmit the torque of the first-stage planet carrier (220), and is supported in the middle by the second-stage sun gear bearing (640).

[0023] The second-stage planet carrier (320) is connected to the second-stage sun gear (310) through second-stage planet gears on the inner side. Its shaft end penetrates through the rest of the system and is connected to the wheel unit (500), and is fixedly connected with the hub flange to serve as the drive shaft of the wheel unit (500). At the same time, a spline hub is provided on the outer ring, and it can be locked and connected or disengaged from the locking engagement sleeve of the first-stage shifting mechanism (250) during multi-mode shifting. The middle part is supported by the output end bearing (610) and the second-stage planet carrier bearing (630) respectively.

[0024] The second-stage ring gear (330) is connected to the outer side of the second-stage planet carrier (320) at one end, and has a spline connection at the other end, and is supported by the second-stage ring gear bearing (620).

[0025] The differential input gear (340) has its shaft end connected to the second-stage ring gear (330) through splines. The gear end forms a differential structure with the differential output gear of the first-stage differential ring gear (230) and the second-stage planetary gear train (300). At the same time, a spline hub is provided on the outer ring of the shaft end.

[0026] The second - stage shifting mechanism (350) mainly consists of a second - stage shifting motor, a locking engagement sleeve, and a second - stage shifting mechanism housing. The position of the second - stage shifting mechanism housing itself remains unchanged and is stationary relative to the multi - mode integrated redundant drive - brake integrated electric wheel system. The second - stage shifting motor controls the locking engagement sleeve to perform shifting operations. The second - stage shifting motor has four gears: 1, 2, 3, and 4. Only one gear can be executed at a time. Gear 1 controls the locking engagement sleeve to move leftward, lock and connect with the spline hub of the differential input gear (340), and disengage from the spline hub of the first - stage differential ring gear (230). Gear 2 controls the locking engagement sleeve to be in the middle position, and at the same time lock and connect with the spline hub of the differential input gear (340) and the spline hub of the first - stage differential ring gear (230). Gear 3 controls the locking engagement sleeve to move rightward, disengage from the spline hub of the differential input gear (340), and lock and connect with the spline hub of the first - stage differential ring gear (230). Gear 4 controls the locking engagement sleeve to move to the rightmost end, and at the same time disengage from the spline hub of the differential input gear (340) and the spline hub of the first - stage differential ring gear (230).

[0027] The differential output gear (360) forms a differential structure with the first - stage differential ring gear (230) and the differential input gear (340) at one end, and is meshed and connected with the electromechanical brake input gear (410) at the other end. During the braking condition, it transmits the torque of the hub motor (100) to the electromechanical brake input gear (410).

[0028] Preferably, the braking system (400) is characterized in that it includes:

[0029] The braking system (400) itself does not carry a separate electromechanical brake execution motor, but through the first - stage planetary gear train (200), the second - stage planetary gear train (300), and multi - mode shifting operations, the hub motor (100) has the function of simultaneously acting as an electromechanical brake execution motor;

[0030] The electromechanical brake input gear (410) has a gear end meshed and connected with the differential output gear (360) to transmit the torque output by the hub motor (100) under the braking condition;

[0031] The brake disc (430) is fixedly connected to the hub flange of the wheel unit (500);

[0032] Electromechanical braking actuator (420); mainly composed of a ball screw mechanism, a brake caliper, a return spring, and a braking clamping force sensor. The ball screw mechanism is used to convert the rotational motion of the electromechanical braking input gear (410) into the linear motion of the ball nut, thereby actuating the brake caliper to clamp the brake disc (430). The brake caliper is equipped with brake pads to clamp the brake disc (430), and there is a braking gap between it and the brake disc (430) when not working. The return spring is used for the brake caliper to retract after the braking command ends to cancel braking. The braking clamping force sensor is used to monitor the braking clamping force of the braking system (400) in real time to provide a reference for the multi-mode shifting operation timing. When the vehicle is in the braking condition, the electromechanical braking input gear (410) transmits the torque output under the braking condition of the in-wheel motor (100) to the electromechanical braking actuator (420), causing it to actuate the brake caliper to clamp the brake disc (430).

[0033] Preferably, the multi-mode integrated redundant drive and brake integrated in-wheel system is characterized in that the rotation direction reference system and working modes include:

[0034] Define the rotation direction reference system. When the wheel unit (500) moves forward in the positive direction, the direction of its own rotation around the rotation axis is the positive direction. When the electromechanical braking input gear (410) rotates in the reverse direction, the electromechanical braking actuator (420) clamps the brake disc (430);

[0035] The working modes of the multi-mode integrated redundant drive and brake integrated in-wheel system are mainly divided into a driving mode, a driving braking mode, a reverse braking mode, and a parking braking mode;

[0036] Among them, the driving braking mode is a multi-mode driving braking mode, which works under the braking condition during driving. It can be switched to three modes: a pure electric braking mode, an active braking mode, and a composite braking mode according to different usage scenarios. Among them, the pure electric braking mode is mainly for medium and high-speed cruise speed regulation and relatively gentle braking deceleration conditions. The active braking mode is mainly for short braking, emergency braking conditions during low-speed driving in urban complex traffic scenarios, and braking conditions during short-time waiting for traffic lights, as well as braking conditions when the on-vehicle power battery has a high charge and the energy recovery charging efficiency is low and high-power regenerative braking cannot be performed. The composite braking mode is mainly for braking conditions when the on-vehicle power battery has a low charge and maximum energy recovery is required, as well as braking conditions with high speed, long distance, and large braking intensity.

[0037] Preferably, it is characterized in that the driving mode control method includes:

[0038] Drive mode, working under driving conditions, the power characteristic of the in-wheel motor works in the first quadrant, providing driving torque for the vehicle drive. At this time, the first-stage shifting mechanism (250) is in the 2nd and 4th gears, and the second-stage shifting mechanism (350) is in the 2nd gear. At this time, the spline hub of the differential input gear (340) and the spline hub of the first-stage differential ring gear (230) are locked and connected to the locking engagement sleeve and remain stationary. At the same time, the constant-speed engagement sleeve (240) disengages from the spline hub of the first-stage planetary carrier (220) and the spline hub of the first-stage differential ring gear (230). Then the first-stage planetary carrier (220) can rotate normally. At the same time, the second-stage planetary carrier (320) disengages from the locking engagement sleeve and can rotate normally, and transmits the driving torque of the in-wheel motor (100) to make the wheel unit (500) rotate.

[0039] Preferably, it is characterized in that the reverse braking mode control method includes:

[0040] Reverse braking mode, working under the braking conditions during reverse driving, the power characteristic of the in-wheel motor works in the third quadrant, and the in-wheel motor (100) rotates in reverse. At this time, the first-stage shifting mechanism (250) is in the 2nd and 4th gears, and the second-stage shifting mechanism (350) is in the 1st gear. At this time, the spline hub of the differential input gear (340) is locked and connected to the locking engagement sleeve and remains stationary, and the spline hub of the first-stage differential ring gear (230) disengages from the locking engagement sleeve and can rotate normally. At the same time, the constant-speed engagement sleeve (240) disengages from the spline hub of the first-stage planetary carrier (220) and the spline hub of the first-stage differential ring gear (230). Then the first-stage planetary carrier (220) can rotate in a different direction and at a different speed from the first-stage differential ring gear (230). At the same time, the second-stage planetary carrier (320) disengages from the locking engagement sleeve and can rotate normally. At this time, the in-wheel motor (100) simultaneously serves as the energy source for the reverse rotation of the wheel unit (500) and the braking work of the braking system (400). Since the electromechanical braking actuator (420) gradually clamps the brake disc (430), it is difficult for the energy output by the in-wheel motor (100) to flow to the reverse rotation of the wheel unit (500), but more of it flows to the electromechanical braking actuator (420) to promote it to further clamp the brake disc (430), forming a braking force increasing effect. When releasing the brake, only need to reduce the output power of the in-wheel motor (100) so that the energy flowing to the electromechanical braking actuator (420) is not enough to overcome the elastic force of the return spring, so that the brake block automatically retracts and separates.

[0041] Preferably, it is characterized in that the parking braking mode control method includes:

[0042] Park brake mode, working under the park brake condition. At this time, the vehicle speed is zero, and the power characteristic of the in-wheel motor works in the first quadrant. The in-wheel motor (100) rotates forward. First, the first-stage shifting mechanism (250) is in the 2nd and 3rd gears, and the second-stage shifting mechanism (350) is in the 1st gear. At this time, the spline hub of the differential input gear (340) is locked and connected to the locking engagement sleeve and remains stationary. The spline hub of the first-stage differential ring gear (230) is disengaged from the locking engagement sleeve and can rotate normally. At the same time, the constant-speed engagement sleeve (240) is disengaged from the spline hub of the first-stage planet carrier (220) and the spline hub of the first-stage differential ring gear (230). Then, the first-stage planet carrier (220) can rotate in a different direction and at a different speed from the first-stage differential ring gear (230). The second-stage planet carrier (320) is locked and connected to the locking engagement sleeve and remains stationary, ensuring that the wheel unit (500) cannot rotate. At this time, the in-wheel motor (100) serves as the energy source for the braking system (400) to perform braking work. After the electromechanical braking actuator (420) quickly clamps the brake disc (430), the first-stage park brake redundancy is formed. Subsequently, the first-stage shifting mechanism (250) is switched to the 1st and 3rd gears, and the second-stage shifting mechanism (350) is switched to the 2nd gear, causing all the first-stage planetary gear train (200) and the second-stage planetary gear train (300) to self-lock and remain stationary. The in-wheel motor (100) is turned off, forming the second-stage park brake redundancy. When releasing the brake, only need to switch the first-stage shifting mechanism (250) back to the 2nd and 3rd gears, and the second-stage shifting mechanism (350) back to the 1st gear. At this time, the in-wheel motor (100) is not powered. Due to the action of the return spring, the brake block of the electromechanical braking actuator (420) automatically retracts and separates from the brake disc (430), and at the same time drives the electromechanical braking input gear (410) to rotate, finally causing the in-wheel motor (100) to rotate idly (the energy recovery is small and can be ignored).

[0043] Preferably, it is characterized in that the driving brake mode control method includes:

[0044] Pure electric braking mode: The power characteristic of the in-wheel motor works in the fourth quadrant. Using the drag torque of the in-wheel motor (100), braking torque is provided for the whole vehicle braking. At this time, the first-stage shifting mechanism (250) is in the 2nd and 4th gears, and the second-stage shifting mechanism (350) is in the 2nd gear. At this time, the spline hub of the differential input gear (340) and the spline hub of the first-stage differential ring gear (230) are locked and connected with the locking sleeve and remain stationary. At the same time, the constant-speed engaging sleeve (240) is disengaged from the spline hub of the first-stage planet carrier (220) and the spline hub of the first-stage differential ring gear (230). Then the first-stage planet carrier (220) can rotate normally. At the same time, the second-stage planet carrier (320) is disengaged from the locking sleeve and can rotate normally, enabling the wheel unit (500) to drive the in-wheel motor (100) to perform braking energy recovery;

[0045] Active braking mode: The power characteristic of the in-wheel motor works in the first quadrant. The in-wheel motor (100) rotates forward. At this time, the first-stage shifting mechanism (250) is in the 1st and 4th gears, and the second-stage shifting mechanism (350) is in the 1st gear. At this time, the spline hub of the differential input gear (340) is locked and connected with the locking sleeve and remains stationary. The spline hub of the first-stage differential ring gear (230) is disengaged from the locking sleeve and can rotate normally. At the same time, the constant-speed engaging sleeve (240) is connected with the spline hub of the first-stage planet carrier (220) and the spline hub of the first-stage differential ring gear (230), enabling the first-stage sun gear (210), the first-stage planet carrier (220), and the first-stage differential ring gear (230) to rotate at the same speed and in the same direction. The second-stage planet carrier (320) is disengaged from the locking sleeve and can rotate normally. At this time, the in-wheel motor (100) simultaneously serves as the power source for the forward rotation drive of the wheel unit (500) and the braking work of the braking system (400). Since the electromechanical braking actuator (420) gradually clamps the brake disc (430), it is difficult for the energy output by the in-wheel motor (100) to flow to the forward rotation drive of the wheel unit (500), but more energy flows to the electromechanical braking actuator (420) to prompt it to further clamp the brake disc (430), forming a braking force increasing effect. When releasing the brake, only the output power of the in-wheel motor (100) needs to be reduced so that the energy flowing to the electromechanical braking actuator (420) is not sufficient to overcome the elastic force of the return spring, thereby enabling the brake block to automatically retract and separate from the brake disc (430);

[0046] Compound braking mode, the power characteristic of the in-wheel motor works in the fourth quadrant. The remaining kinetic energy of the whole vehicle drives each transmission mechanism through the rotation of the wheel unit (500) to supply energy for the energy recovery of the in-wheel motor (100) and the braking work of the braking system (400). First, the first-stage shift mechanism (250) is in the 2nd and 4th gears, and the second-stage shift mechanism (350) is in the 3rd gear. At this time, the spline hub of the differential input gear (340) is disengaged from the locking engagement sleeve and can rotate normally, and the spline hub of the first-stage differential ring gear (230) is locked and connected to the locking engagement sleeve and remains stationary. At the same time, the constant-velocity engagement sleeve (240) is disengaged from the spline hub of the first-stage planet carrier (220) and the spline hub of the first-stage differential ring gear (230), so the first-stage planet carrier (220) can rotate in a different direction and at a different speed from the first-stage differential ring gear (230). The second-stage planet carrier (320) is disengaged from the locking engagement sleeve and can rotate normally. The remaining kinetic energy of the whole vehicle will drive the in-wheel motor (100) for energy recovery to achieve electric braking, and at the same time drive the electromechanical braking input gear (410) to rotate, so that the electromechanical braking actuator (420) clamps the brake disc (430) to achieve frictional braking, and the braking clamping force is detected in real time by the braking clamping force sensor. When the braking clamping force reaches the maximum value but the braking task is still not completed, but at this time the electromechanical braking input gear (410) cannot rotate further, then the first-stage shift mechanism (250) remains in the 2nd and 4th gears, and the second-stage shift mechanism (350) switches to the 4th gear, so that the spline hub of the first-stage differential ring gear (230) is disengaged from the locking engagement sleeve and can rotate normally. The remaining kinetic energy of the whole vehicle not only provides energy for the braking work of the braking system (400), but also provides energy for the energy recovery of the in-wheel motor (100) through two different torque transmission paths, forming multi-stage braking redundancy. When releasing the brake, only need to increase the electric braking power of the in-wheel motor (100), and at the same time the remaining kinetic energy of the whole vehicle is continuously decreasing, so that the energy flowing to the electromechanical braking actuator (420) is further reduced and is not enough to overcome the elastic force of the return spring, so that the brake block automatically retracts and separates from the brake disc (430).

[0047] Advantages of the present invention:

[0048] 1. The present invention provides a multi-mode integrated redundant drive and brake integrated in-wheel motor system, which integrates the in-wheel motor, planetary gear train, braking system and wheel unit, is conducive to the modular design and development of the wheel end structure. For various types of vehicles with different drive axle numbers and different usage scenarios, the corresponding in-wheel motor system can be directly selected according to requirements, reducing the development cost of the whole vehicle to achieve personalized demand design.

[0049] 2. The present invention provides a multi-mode integrated redundant drive and brake integrated electric wheel system. Its hub motor can provide driving torque under the vehicle driving condition, recover braking energy under the electric braking condition, and can also achieve multi-mode switching through coordinated cooperation with a two-stage planetary gear train. Under specific braking conditions, it serves as the actuator motor of the electromechanical braking system to provide driving torque for the brake caliper to clamp the brake disc, thereby canceling the original actuator motor of the electromechanical braking system. While improving the utilization rate of the hub motor, it saves the wheel-side space, reduces the sprung mass, improves the vehicle economy, and realizes the integrated design and control of drive and brake.

[0050] 3. The present invention provides a multi-mode integrated redundant drive and brake integrated electric wheel system, which can achieve multi-mode switching of drive mode, service braking mode, reverse braking mode, and parking braking mode through multi-mode shifting operations. At the same time, the traditional parking braking system is canceled, and the hub motor actively clamps the brake disc, and the self-locking of the two-stage planetary gear train is used to realize the dual redundant function of parking braking.

[0051] 4. The present invention provides a multi-mode integrated redundant drive and brake integrated electric wheel system. The service braking mode is further divided into three types: pure electric braking mode, active braking mode, and compound braking mode according to its different service braking conditions. Among them, the pure electric braking mode is mainly for medium and high-speed cruise speed regulation and relatively gentle braking deceleration conditions. The active braking mode is mainly for short braking, emergency braking conditions during low-speed driving and braking conditions during short-time waiting for traffic lights in urban complex traffic scenarios, and braking conditions when the on-vehicle power battery has a high charge and the energy recovery charging efficiency is low and high-power regenerative braking cannot be performed. The compound braking mode is mainly for braking conditions when the on-vehicle power battery has a low charge and maximum energy recovery is required and long-distance braking with high intensity, so as to achieve full coverage of multi-scenario braking functions. In addition, the compound braking mode provides energy for energy recovery of the hub motor through two different torque transmission paths to realize the dual redundant function of compound braking.

[0052] 5. The present invention also provides a control method for the multi-mode switching of the multi-mode integrated redundant drive and brake integrated electric wheel system, which can select a suitable working mode according to different working conditions. This method has certain generality and reference significance and can play the same role in electric wheel systems with other similar structural schemes. Brief Description of the Drawings

[0053] Figure 1 is a schematic structural diagram of the multi-mode integrated redundant drive and brake integrated electric wheel system described in the present invention;

[0054] Figure 2 is a torque transmission route diagram of the active braking mode of the multi-mode integrated redundant drive and brake integrated electric wheel system described in the present invention;

[0055] Figure 3 This is the torque transmission route diagram of the composite braking mode of the multi-mode integrated redundant drive-brake integrated electric wheel system of the present invention (first gear shift);

[0056] Figure 4 This is the torque transmission route diagram of the composite braking mode of the multi-mode integrated redundant drive-brake integrated electric wheel system of the present invention (second gear shift);

[0057] Figure 5 This is the multi-mode switching control flow block diagram of the multi-mode integrated redundant drive-brake integrated electric wheel system of the present invention. Detailed implementation mode

[0058] The following further describes the present invention in detail with reference to the drawings, so that those skilled in the art can implement it according to the text of the specification.

[0059] The present invention proposes a multi-mode integrated redundant drive-brake integrated electric wheel system, such as Figure 1 And Figure 2 , which mainly includes: a hub motor (100), a first-stage planetary gear train (200), a second-stage planetary gear train (300), a braking system (400), a wheel unit (500), and a bearing system (600).

[0060] Among them, the hub motor (100) is a high-speed inner rotor motor, and its output end is connected to the first-stage sun gear in the first-stage planetary gear train, and is used to provide the execution torque for the drive and braking conditions of the multi-mode integrated redundant drive-brake integrated electric wheel system.

[0061] Among them, the first-stage planetary gear train (200) is used to transmit the torque output by the hub motor (100), and at the same time realizes the drive-brake integration function of the multi-mode integrated redundant drive-brake integrated electric wheel system through multi-mode gear shifting operations. It mainly includes: a first-stage sun gear (210), a first-stage planetary carrier (220), a first-stage differential ring gear (230), a same-speed coupling sleeve (240), and a first-stage gear shifting mechanism (250).

[0062] Among them, for the first-stage sun gear (210), the shaft end is connected to the output end of the in-wheel motor (100) through a spline to transmit the torque of the in-wheel motor (100); for the first-stage planet carrier (220), the inner side is connected to the first-stage sun gear (210) through a first-stage planet gear, the shaft end is provided with a spline connection, and the outer ring is provided with a spline hub; for the first-stage differential ring gear (230), one end is connected to the outer side of the first-stage planet carrier (220), and the other end is connected to the differential input gear and the differential output gear of the second-stage planetary gear train (300) to form a differential structure, and spline hubs are provided at both ends; for the synchro engaging sleeve (240), it is not fixedly connected to the first-stage shifting mechanism of the first-stage planetary gear train (200) and can slide relatively. During multi-mode shifting, it can be connected to the spline hub of the first-stage planet carrier (220) and the spline hub of the first-stage differential ring gear (230) to make the first-stage planet carrier (220) and the first-stage differential ring gear (230) rotate at the same speed and in the same direction. When disengaged, they can rotate at different speeds and in different directions; for the first-stage shifting mechanism (250), it mainly consists of a first-stage shifting motor, a fork, a locking engaging sleeve, and a first-stage shifting mechanism housing. The position of the first-stage shifting mechanism housing itself remains unchanged and is stationary relative to the multi-mode integrated redundant drive-brake integrated in-wheel system. The first-stage shifting motor controls the fork and the locking engaging sleeve to perform shifting operations respectively. The first-stage shifting motor has a total of four gears: 1, 2, 3, and 4. Two gears are executed each time among the four gears. Among them, gears 1 and 2 are mutually exclusive, controlling the fork to move left and right respectively, thereby driving the synchro engaging sleeve (240) to be connected to or disengaged from the spline hub of the first-stage planet carrier (220) and the spline hub of the first-stage differential ring gear (230). Gears 3 and 4 are mutually exclusive, controlling the locking engaging sleeve to move left and right respectively, thereby being locked and connected to or disengaged from the spline hub of the second-stage planet carrier of the second-stage planetary gear train (300).

[0063] Among them, the second-stage planetary gear train (300) is used to cooperate with the first-stage planetary gear train (200) to transmit the torque output by the in-wheel motor (100), and at the same time, through multi-mode shifting operations, achieve the drive-brake integration function of the multi-mode integrated redundant drive-brake integrated in-wheel system. It mainly includes: a second-stage sun gear (310), a second-stage planet carrier (320), a second-stage ring gear (330), a differential input gear (340), a second-stage shifting mechanism (350), and a differential output gear (360).

[0064] Among them, for the secondary sun gear (310), the shaft end is connected to the primary planet carrier (220) through splines to transmit the torque of the primary planet carrier (220), and the middle part is supported by the secondary sun gear bearing (640); for the secondary planet carrier (320), the inner side is connected to the secondary sun gear (310) through secondary planet gears respectively, the shaft end penetrates through the rest of the system and is connected to the wheel unit (500), and is fixedly connected with the hub flange to serve as the drive shaft of the wheel unit (500). At the same time, a spline hub is provided on the outer ring, and it can be locked and connected or disengaged with the locking engagement sleeve of the primary shifting mechanism (250) during multi-mode shifting. The middle part is supported by the output end bearing (610) and the secondary planet carrier bearing (630) respectively; among them

[0065] is supported by the output end bearing (610) and the secondary planet carrier bearing (630);

[0066] The secondary ring gear (330) is connected to the outer side of the secondary planet carrier (320) at one end, and has a spline connection at the other end, and is supported by the secondary ring gear bearing (620); for the differential input gear (340), the shaft end is connected to the secondary ring gear (330) through splines, and the gear end forms a differential structure with the differential output gear of the primary differential ring gear (230) and the secondary planetary gear train (300). At the same time, a spline hub is provided on the outer ring of the shaft end; for the secondary shifting mechanism (350), it mainly consists of a secondary shifting motor, a locking engagement sleeve, and a secondary shifting mechanism housing. Among them, the position of the secondary shifting mechanism housing remains unchanged and is stationary relative to the multi-mode integrated redundant drive and brake integrated electric wheel system. The secondary shifting motor will control the locking engagement sleeve to perform shifting operations. The secondary shifting motor has a total of four gears: 1, 2, 3, and 4. Only one gear can be executed each time. Gear 1 controls the locking engagement sleeve to move left and lock and connect with the spline hub of the differential input gear (340) and disengage from the spline hub of the primary differential ring gear (230). Gear 2 controls the locking engagement sleeve to be in the middle position and lock and connect with the spline hubs of both the differential input gear (340) and the primary differential ring gear (230) at the same time. Gear 3 controls the locking engagement sleeve to move right and disengage from the spline hub of the differential input gear (340) and lock and connect with the spline hub of the primary differential ring gear (230). Gear 4 controls the locking engagement sleeve to move to the rightmost end and disengage from the spline hubs of both the differential input gear (340) and the primary differential ring gear (230) at the same time; for the differential output gear (360), one end forms a differential structure with the primary differential ring gear (230) and the differential input gear (340), and the other end is meshed and connected to the electromechanical brake input gear (410). During the braking condition, it transmits the torque of the hub motor (100) to the electromechanical brake input gear (410).

[0067] The braking system (400) is configured to provide the braking torque during the braking condition of the multi-mode integrated redundant drive-brake integrated electric wheel system, and mainly includes: an electromechanical braking input gear (410), an electromechanical braking actuator (420), and a brake disc (430).

[0068] The braking system (400) itself does not carry a separate electromechanical braking actuator motor, but through the first-level planetary gear train (200), the second-level planetary gear train (300), and multi-mode shifting operations, the hub motor (100) is enabled to function as an electromechanical braking actuator motor at the same time; the electromechanical braking input gear (410), the gear end of which is meshed and connected with the differential output gear (360) to transmit the torque output by the hub motor (100) under the braking condition; the brake disc (430) is fixedly connected to the hub flange of the wheel unit (500); the electromechanical braking actuator (420) mainly consists of a ball screw mechanism, a brake caliper, a return spring, and a braking clamping force sensor. The ball screw mechanism is used to convert the rotational motion of the electromechanical braking input gear (410) into the linear motion of the ball nut, thereby actuating the brake caliper to clamp the brake disc (430). The brake caliper is equipped with brake pads to clamp the brake disc (430), and there is a braking gap between the brake caliper and the brake disc (430) when not working. The return spring is used for the brake caliper to retract after the braking command ends to cancel the braking. The braking clamping force sensor is used to monitor the braking clamping force of the braking system (400) in real time to provide a reference for the multi-mode shifting operation timing. When the vehicle is in the braking condition, the electromechanical braking input gear (410) transmits the torque output by the hub motor (100) under the braking condition to the electromechanical braking actuator (420), causing it to actuate the brake caliper to clamp the brake disc (430).

[0069] The multi-mode integrated redundant drive-brake integrated electric wheel system needs to define a reference system for the rotation direction. When the wheel unit (500) moves forward in the positive direction, the direction around its own rotation axis is the positive direction. When the electromechanical braking input gear (410) rotates in the reverse direction, the electromechanical braking actuator (420) clamps the brake disc (430).

[0070] The working modes of the multi-mode integrated redundant drive-brake integrated electric wheel system are mainly divided into a driving mode, a driving braking mode, a reverse braking mode, and a parking braking mode.

[0071] Among them, in the driving mode, it works under the driving condition. The power characteristic of the in-wheel motor works in the first quadrant to provide driving torque for the vehicle. At this time, the first-stage shifting mechanism (250) is in the 2nd and 4th gears, and the second-stage shifting mechanism (350) is in the 2nd gear. At this time, the spline hub of the differential input gear (340) and the spline hub of the first-stage differential ring gear (230) are locked and connected to the locking engagement sleeve and remain stationary. At the same time, the constant-speed engagement sleeve (240) disengages from the spline hub of the first-stage planet carrier (220) and the spline hub of the first-stage differential ring gear (230). Then the first-stage planet carrier (220) can rotate normally. At the same time, the second-stage planet carrier (320) disengages from the locking engagement sleeve and can rotate normally, and transmits the driving torque of the in-wheel motor (100) to make the wheel unit (500) rotate.

[0072] Among them, in the reverse braking mode, it works under the braking condition during reverse. The power characteristic of the in-wheel motor works in the third quadrant, and the in-wheel motor (100) rotates in reverse. At this time, the first-stage shifting mechanism (250) is in the 2nd and 4th gears, and the second-stage shifting mechanism (350) is in the 1st gear. At this time, the spline hub of the differential input gear (340) is locked and connected to the locking engagement sleeve and remains stationary, and the spline hub of the first-stage differential ring gear (230) disengages from the locking engagement sleeve and can rotate normally. At the same time, the constant-speed engagement sleeve (240) disengages from the spline hub of the first-stage planet carrier (220) and the spline hub of the first-stage differential ring gear (230). Then the first-stage planet carrier (220) can rotate in a different direction and at a different speed from the first-stage differential ring gear (230). At the same time, the second-stage planet carrier (320) disengages from the locking engagement sleeve and can rotate normally. At this time, the in-wheel motor (100) simultaneously serves as the energy source for the reverse rotation of the wheel unit (500) and the braking work of the braking system (400). Since the electromechanical braking actuator (420) gradually clamps the brake disc (430), it makes it difficult for the energy output by the in-wheel motor (100) to flow to the reverse rotation of the wheel unit (500), but more energy flows to the electromechanical braking actuator (420) to prompt it to further clamp the brake disc (430), forming a braking force increasing effect. When releasing the brake, only need to reduce the output power of the in-wheel motor (100) so that the energy flowing to the electromechanical braking actuator (420) is not enough to overcome the elastic force of the return spring, so that the brake block automatically retracts and separates.

[0073] Among them, the parking brake mode operates under the parking brake condition. At this time, the vehicle speed is zero, and the power characteristic of the in-wheel motor works in the first quadrant. The in-wheel motor (100) rotates forward. First, the first-stage shifting mechanism (250) is in the 2nd and 3rd gears, and the second-stage shifting mechanism (350) is in the 1st gear. At this time, the spline hub of the differential input gear (340) is locked and connected to the locking engagement sleeve and remains stationary, and the spline hub of the first-stage differential ring gear (230) is disengaged from the locking engagement sleeve and can rotate normally. At the same time, the constant-speed engagement sleeve (240) is disengaged from the spline hub of the first-stage planet carrier (220) and the spline hub of the first-stage differential ring gear (230). Then, the first-stage planet carrier (220) can rotate in a different direction and at a different speed from the first-stage differential ring gear (230). The second-stage planet carrier (320) is locked and connected to the locking engagement sleeve and remains stationary, ensuring that the wheel unit (500) cannot rotate. At this time, the in-wheel motor (100) serves as the energy source for the braking system (400) to perform braking work. After the electromechanical brake actuator (420) quickly clamps the brake disc (430), the first-stage parking brake redundancy is formed. Subsequently, the first-stage shifting mechanism (250) switches to the 1st and 3rd gears, and the second-stage shifting mechanism (350) switches to the 2nd gear, making all the first-stage planetary gear train (200) and the second-stage planetary gear train (300) self-lock and remain stationary, and turning off the in-wheel motor (100) to form the second-stage parking brake redundancy. When releasing the brake, only need to switch the first-stage shifting mechanism (250) back to the 2nd and 3rd gears, and the second-stage shifting mechanism (350) back to the 1st gear. At this time, the in-wheel motor (100) does not supply energy, and due to the action of the return spring, the brake block of the electromechanical brake actuator (420) automatically retracts and separates from the brake disc (430), and at the same time drives the electromechanical brake input gear (410) to rotate, finally making the in-wheel motor (100) idle (the energy recovery is small and can be ignored).

[0074] Among them, the driving brake mode is a multi-mode driving brake mode, which operates under the braking condition during driving. It can be switched to three modes: pure electric braking mode, active braking mode, and compound braking mode respectively according to different usage scenarios. Among them, the pure electric braking mode is mainly for medium and high-speed cruise speed regulation and relatively gentle braking and deceleration conditions. The active braking mode is mainly for short braking, emergency braking conditions during low-speed driving in urban complex traffic scenarios, braking conditions during short-time waiting for traffic lights, and braking conditions in scenarios where the on-vehicle power battery has a high charge and the energy recovery charging efficiency is low and high-power regenerative braking cannot be performed. The compound braking mode is mainly for braking conditions where the on-vehicle power battery has a low charge and maximum energy recovery is required, and braking conditions with a large braking intensity over a long distance.

[0075] Among them, in the pure electric braking mode: the power characteristic of the in-wheel motor works in the fourth quadrant, and the drag torque of the in-wheel motor (100) is utilized to provide braking torque for the whole vehicle braking. At this time, the first-stage shifting mechanism (250) is in the 2nd and 4th gears, and the second-stage shifting mechanism (350) is in the 2nd gear. At this time, the spline hub of the differential input gear (340) and the spline hub of the first-stage differential ring gear (230) are locked and connected with the locking sleeve and remain stationary. At the same time, the constant-speed engaging sleeve (240) is disengaged from the spline hub of the first-stage planet carrier (220) and the spline hub of the first-stage differential ring gear (230), then the first-stage planet carrier (220) can rotate normally. At the same time, the second-stage planet carrier (320) is disengaged from the locking sleeve and can rotate normally, so that the wheel unit (500) can drive the in-wheel motor (100) to perform braking energy recovery.

[0076] Among them, in the active braking mode, the torque transmission route is as Figure 2 shown. The power characteristic of the in-wheel motor works in the first quadrant, and the in-wheel motor (100) rotates forward. At this time, the first-stage shifting mechanism (250) is in the 1st and 4th gears, and the second-stage shifting mechanism (350) is in the 1st gear. At this time, the spline hub of the differential input gear (340) is locked and connected with the locking sleeve and remains stationary, and the spline hub of the first-stage differential ring gear (230) is disengaged from the locking sleeve and can rotate normally. At the same time, the constant-speed engaging sleeve (240) is connected with the spline hub of the first-stage planet carrier (220) and the spline hub of the first-stage differential ring gear (230), so that the first-stage sun gear (210), the first-stage planet carrier (220), and the first-stage differential ring gear (230) can rotate at the same speed and in the same direction. The second-stage planet carrier (320) is disengaged from the locking sleeve and can rotate normally. At this time, the in-wheel motor (100) simultaneously serves as the power source for the forward rotation drive of the wheel unit (500) and the braking work of the braking system (400). At this time, the energy relationship of each system of the multi-mode integrated redundant drive-brake integrated in-wheel system is as shown in Equations 1-3.

[0077]

[0078] Among them, P m is the average output power of the in-wheel motor (100), η is the working efficiency of the multi-mode integrated redundant drive-brake integrated in-wheel system, comprehensively considering factors such as transmission efficiency, rolling resistance, and moment of inertia. M is the mass of the whole vehicle, v0 and v are the vehicle speeds at the start and end of braking respectively, E s is the elastic potential energy when the return spring is completely compressed, Q is the heat dissipated by the electromechanical braking actuator (420) clamping the brake disc (430) for friction braking, P embis the average power consumption of the wheel hub motor (100) when it is used as an actuating motor for the braking work of the braking system (400), and is used to control F c , F c is the brake clamping force of the electronic mechanical brake actuator (420), μ is the friction coefficient between the brake block and the brake disc (430), R disc is the effective friction radius of the brake disc (430), r is the rolling radius of the wheel unit (500), and t is the braking time. By combining equations 1-3, a closed-loop model of the relationship between the average output power of the wheel hub motor (100), the brake clamping force of the electronic mechanical brake actuator (420), and the vehicle speed can be formed, so the brake clamping force of the electronic mechanical brake actuator (420) and the vehicle speed can be controlled by controlling the average output power of the wheel hub motor (100). During the active braking mode, since the electronic mechanical brake actuator (420) gradually clamps the brake disc (430), it is difficult for the energy output by the wheel hub motor (100) to flow to the wheel unit (500) for forward rotation driving, and the energy flows to the electronic mechanical brake actuator (420) to a greater extent, prompting it to further clamp the brake disc (430), thereby forming a braking force enhancement effect. When releasing the brake, it is only necessary to reduce the output power of the wheel hub motor (100) so that the energy flowing to the electronic mechanical brake actuator (420) is insufficient to overcome the elastic force of the return spring, thereby causing the brake block to automatically retreat and separate from the brake disc (430).

[0079] The compound braking mode has a torque transmission route after two gear shifts as follows: Figure 3 , 4As shown, the power characteristic of the in-wheel motor operates in the fourth quadrant. The remaining kinetic energy of the vehicle drives each transmission mechanism through the rotation of the wheel unit (500) to supply energy for the energy recovery of the in-wheel motor (100) and the braking work of the braking system (400). First, the first-stage shifting mechanism (250) is in the 2nd and 4th gears, and the second-stage shifting mechanism (350) is in the 3rd gear. At this time, the spline hub of the differential input gear (340) is disengaged from the locking engagement sleeve and can rotate normally, while the spline hub of the first-stage differential ring gear (230) is locked and connected to the locking engagement sleeve and remains stationary. At the same time, the constant-speed engagement sleeve (240) is disengaged from the spline hub of the first-stage planet carrier (220) and the spline hub of the first-stage differential ring gear (230). Then, the first-stage planet carrier (220) can rotate in a different direction and at a different speed from the first-stage differential ring gear (230). The second-stage planet carrier (320) is disengaged from the locking engagement sleeve and can rotate normally. The remaining kinetic energy of the vehicle will drive the in-wheel motor (100) to perform energy recovery, realizing electric braking. At the same time, it will drive the electromechanical braking input gear (410) to rotate, causing the electromechanical braking actuator (420) to clamp the brake disc (430), realizing friction braking, and the magnitude of the braking clamping force is detected in real time through the braking clamping force sensor. When the braking clamping force reaches the maximum value but the braking task is still not completed, and at this time the electromechanical braking input gear (410) can no longer rotate further, then the first-stage shifting mechanism (250) remains in the 2nd and 4th gears, and the second-stage shifting mechanism (350) switches to the 4th gear, making the spline hub of the first-stage differential ring gear (230) disengaged from the locking engagement sleeve and able to rotate normally. The remaining kinetic energy of the vehicle not only provides energy for the braking work of the braking system (400), but also provides energy for the energy recovery of the in-wheel motor (100) through two different torque transmission paths, forming multi-stage braking redundancy. At this time, the energy relationship of each system of the multi-mode integrated redundant drive-brake integrated in-wheel motor system is as shown in Equation 4.

[0080]

[0081] Among them, P reg is the average input power when the in-wheel motor (100) performs energy recovery, and P' emb is the average power consumption when the remaining kinetic energy of the vehicle supplies energy for the braking work of the braking system (400) through the rotation of the wheel unit (500), and is used to control the braking clamping force F of the electromechanical braking actuator (420). cThrough Equation 2-4, a closed-loop model of the relationship among the average output power of the in-wheel motor (100), the braking clamping force of the electromechanical braking actuator (420), and the vehicle speed can be formed. Therefore, the braking clamping force of the electromechanical braking actuator (420) and the vehicle speed can be controlled by controlling the average output power of the in-wheel motor (100). When braking is released, only the electric braking power of the in-wheel motor (100) needs to be increased. At the same time, the remaining kinetic energy of the vehicle is continuously decreasing, so that the energy flowing to the electromechanical braking actuator (420) is further reduced and is not sufficient to overcome the elastic force of the return spring, thereby causing the brake pad to automatically retract and separate from the brake disc (430).

[0082] The motion states and gear setting information of each component in different modes of the multi-mode integrated redundant drive and brake integrated electric wheel system are shown in Table 1.

[0083] Table 1 Multi-mode working system state table of the multi-mode integrated redundant drive and brake integrated electric wheel system in this embodiment

[0084]

[0085] The present invention also proposes a control method for multi-mode switching of the multi-mode integrated redundant drive and brake integrated electric wheel system, and the control method includes:

[0086] First, determine the command type of the multi-mode integrated redundant drive and brake integrated electric wheel system. If it is a drive command, the system switches to the drive mode through multi-mode gear shifting operation, and then determines whether forward or reverse driving is required based on whether its target speed is greater than zero, so as to control the rotation drive direction of the hub motor (100); if it is a brake command, first detect the real-time speed. If the real-time speed is less than zero, it is judged as a reverse driving condition, and the system switches to the reverse braking mode; if the real-time speed is equal to zero, it is necessary to further detect whether the parking brake command has been received. If it has been received, the system switches to the parking braking mode. If it has not been received, it is judged as a short-term parking condition, and the system switches to the active braking mode; if the real-time speed is greater than zero, it is judged as a driving condition. First, detect the SOC of the vehicle-mounted power battery. If the SOC of the vehicle-mounted power battery is too low (here, 30% is used as the lower limit threshold), the system switches to the compound braking mode. If the SOC of the vehicle-mounted power battery is too high (here, 90% is used as the upper limit threshold), the system switches to the active braking mode. If the SOC of the vehicle-mounted power battery is between 30% and 90%, the magnitude of the real-time speed and the target braking deceleration is used as the judgment criterion for mode switching. If the braking behavior is relatively gentle and the target braking deceleration is small (here, 0.5g is used as the threshold, where g is the acceleration due to gravity), the system switches to the pure electric braking mode. If the braking behavior is relatively intense and the vehicle is in a high-speed driving state (here, 80 km / h is used as the threshold), the system switches to the compound braking mode. If the braking behavior is relatively intense and the vehicle is in a low-speed driving state, the system switches to the active braking mode; finally, judge whether the driving behavior has ended. If it has not ended, re-judge the command type of the multi-mode integrated redundant drive and brake integrated electric wheel system. If it has ended, the system control task terminates.

[0087] For the specific flow of the control method as Figure 5 , the specific steps are as follows:

[0088] Step 0: Start;

[0089] Step 1: Determine the command type. If it is a drive command, execute Step 2. If it is a brake command, execute Step 6;

[0090] Step 2: Select the drive mode to work and execute Step 3;

[0091] Step 3: Determine whether the target speed is greater than 0. If it is, execute Step 4. If not, execute Step 5;

[0092] Step 4: Control the hub motor to rotate forward for driving and execute Step 17;

[0093] Step 5: Control the hub motor to rotate in reverse for driving and execute Step 17;

[0094] Step 6: Detect the real-time speed. If it is less than 0, execute Step 7. If it is equal to 0, execute Step 8. If it is greater than 0, execute Step 10;

[0095] Step 7: Select the reverse gear braking mode to work and execute Step 17;

[0096] Step 8: Detect whether the parking brake command is received. If so, execute Step 9. If not, execute Step 16;

[0097] Step 9: Select the parking brake mode to work and execute Step 17;

[0098] Step 10: Detect the SOC of the on-vehicle power battery. If it is less than 30%, execute Step 14. If it is between 30% and 90%, execute Step 11. If it is greater than 90%, execute Step 16;

[0099] Step 11: Judge whether the real-time speed is greater than 80 km / h. If so, execute Step 12. If not, execute Step 13;

[0100] Step 12: Judge whether the target braking deceleration is greater than 0.5g. If so, execute Step 14. If not, execute Step 15;

[0101] Step 13: Judge whether the target braking deceleration is greater than 0.5g. If so, execute Step 16. If not, execute Step 15;

[0102] Step 14: Select the compound braking mode to work and execute Step 17;

[0103] Step 15: Select the pure electric braking mode to work and execute Step 17;

[0104] Step 16: Select the active braking mode to work and execute Step 17;

[0105] Step 17: Judge whether the driving is over. If so, execute Step 18. If not, execute Step 1;

[0106] Step 18: End

[0107] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the embodiments. It can be fully applied to various fields suitable for the present invention. For those skilled in the art, additional modifications can be easily achieved. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to the specific details and the examples shown and described herein. Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the embodiments. It can be fully applied to various fields suitable for the present invention. For those skilled in the art, additional modifications can be easily achieved. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to the specific details and the examples shown and described herein.

Claims

1. A multi-mode integrated redundant drive and brake integrated electric wheel system, characterized in that, Comprising: A hub motor (100), which adopts a high-speed inner rotor motor, and its output end is connected to the first-stage sun gear in the first-stage planetary gear train, and is used to provide the execution torque for the driving and braking conditions of the multi-mode integrated redundant drive-brake integrated electric wheel system; The first-stage planetary gear train (200), including a first-stage sun gear (210), a first-stage planetary carrier (220), a first-stage differential ring gear (230), a same-speed coupling sleeve (240), and a first-stage shifting mechanism (250), is used to transmit the torque output by the hub motor (100), and at the same time realizes the drive-brake integrated function of the multi-mode integrated redundant drive-brake integrated electric wheel system through multi-mode shifting operations; The second-stage planetary gear train (300), including a second-stage sun gear (310), a second-stage planetary carrier (320), a second-stage ring gear (330), a differential input gear (340), a second-stage shifting mechanism (350), and a differential output gear (360), is used to cooperate with the first-stage planetary gear train (200) to transmit the torque output by the hub motor (100), and at the same time realizes the drive-brake integrated function of the multi-mode integrated redundant drive-brake integrated electric wheel system through multi-mode shifting operations; The braking system (400), which is composed of an electromechanical braking input gear (410), an electromechanical braking actuator (420), and a brake disc (430), is used to provide the braking torque for the braking condition of the multi-mode integrated redundant drive-brake integrated electric wheel system; The wheel unit (500), mainly composed of a tire, a wheel rim, a wheel spoke, and a hub flange, provides space for the highly integrated layout of each system inside, is used to support the vehicle load, and transmit the driving and braking torques; The bearing system (600), including an output end bearing (610), a second-stage ring gear bearing (620), a second-stage planetary carrier bearing (630), and a second-stage sun gear bearing (640), all adopt deep groove ball bearings, and are used for the support of each transmission component in the first-stage planetary gear train (200) and the second-stage planetary gear train (300), while reducing mechanical friction and improving transmission efficiency and motion accuracy.

2. The multi-mode integrated redundant drive and brake integrated electric wheel system according to claim 1, characterized in that The first-stage planetary gear train (200) is characterized by including: The first-stage sun gear (210), the shaft end of which is connected to the output end of the hub motor (100) through a spline, is used to transmit the torque of the hub motor (100); The first-stage planetary carrier (220), the inner side of which is connected to the first-stage sun gear (210) through a first-stage planetary gear, has a spline connection at the shaft end and a spline hub at the outer circle; The first-stage differential ring gear (230), one end of which is connected to the outer side of the first-stage planetary carrier (220), and the other end is connected to the differential input gear and the differential output gear of the second-stage planetary gear train (300) to form a differential structure, and both ends are provided with spline hubs; The same-speed engaging sleeve (240) is not fixedly connected to the first-stage shifting mechanism of the first-stage planetary gear train (200) and can slide relative to it. During multi-mode shifting, it can be connected to the spline hub of the first-stage planetary carrier (220) and the spline hub of the first-stage differential ring gear (230), causing the first-stage planetary carrier (220) and the first-stage differential ring gear (230) to rotate at the same speed and in the same direction. When disengaged, they can rotate at different speeds and in different directions. The first-stage shifting mechanism (250) mainly consists of a first-stage shifting motor, a fork, a locking engaging sleeve, and a first-stage shifting mechanism housing. The position of the first-stage shifting mechanism housing itself remains unchanged and is stationary relative to the multi-mode integrated redundant drive-brake integrated electric wheel system. The first-stage shifting motor controls the fork and the locking engaging sleeve to perform shifting operations respectively. The first-stage shifting motor has a total of four gears: 1, 2, 3, and 4. Each time, two of the four gears are executed. Among them, gears 1 and 2 are mutually exclusive and control the left and right movement of the fork respectively, thereby driving the same-speed engaging sleeve (240) to connect or disengage from the spline hub of the first-stage planetary carrier (220) and the spline hub of the first-stage differential ring gear (230). Gears 3 and 4 are mutually exclusive and control the left and right movement of the locking engaging sleeve respectively, thereby locking and connecting or disengaging from the spline hub of the second-stage planetary carrier of the second-stage planetary gear train (300).

3. The multi-mode integrated redundant drive and brake integrated electric wheel system according to claim 2, characterized in that The second-stage planetary gear train (300) is characterized by including: The second-stage sun gear (310) has its shaft end connected to the first-stage planetary carrier (220) through splines to transmit the torque of the first-stage planetary carrier (220), and is supported in the middle by the second-stage sun gear bearing (640). The second-stage planetary carrier (320) is connected to the second-stage sun gear (310) through second-stage planetary gears on the inner side. Its shaft end passes through the rest of the system and is connected to the wheel unit (500), and is fixedly connected with the hub flange to serve as the drive shaft of the wheel unit (500). At the same time, a spline hub is provided on the outer ring. During multi-mode shifting, it can be locked and connected or disengaged from the locking engaging sleeve of the first-stage shifting mechanism (250). The middle part is supported by the output end bearing (610) and the second-stage planetary carrier bearing (630) respectively. The second-stage ring gear (330) is connected to the outer side of the second-stage planetary carrier (320) at one end, has a spline connection at the other end, and is supported by the second-stage ring gear bearing (620). The differential input gear (340) has its shaft end connected to the second-stage ring gear (330) through splines. The gear end forms a differential structure with the differential output gear of the first-stage differential ring gear (230) and the second-stage planetary gear train (300). At the same time, a spline hub is provided on the outer circle of the shaft end. The second - stage shifting mechanism (350) mainly consists of a second - stage shifting motor, a locking engagement sleeve, and a second - stage shifting mechanism housing. The position of the second - stage shifting mechanism housing itself remains unchanged and is stationary relative to the multi - mode integrated redundant drive - brake integrated electric wheel system. The second - stage shifting motor controls the locking engagement sleeve to perform the shifting operation. The second - stage shifting motor has four gears: 1, 2, 3, and 4. Only one gear can be executed at a time. Gear 1 controls the locking engagement sleeve to move leftward, lock and connect with the spline hub of the differential input gear (340), and disengage from the spline hub of the first - stage differential ring gear (230). Gear 2 controls the locking engagement sleeve to be in the middle position, and at the same time, lock and connect with the spline hub of the differential input gear (340) and the spline hub of the first - stage differential ring gear (230). Gear 3 controls the locking engagement sleeve to move rightward, disengage from the spline hub of the differential input gear (340), and lock and connect with the spline hub of the first - stage differential ring gear (230). Gear 4 controls the locking engagement sleeve to move to the rightmost end, and at the same time, disengage from the spline hub of the differential input gear (340) and the spline hub of the first - stage differential ring gear (230). The differential output gear (360), one end forms a differential structure with the first - stage differential ring gear (230) and the differential input gear (340), and the other end is meshed and connected with the electromechanical brake input gear (410). During the braking condition, it transmits the torque of the hub motor (100) to the electromechanical brake input gear (410).

4. The multi-mode integrated redundant drive and brake integrated electric wheel system according to claim 3, characterized in that The braking system (400) is characterized by including: The braking system (400) itself does not carry a separate electromechanical brake execution motor, but through the first - stage planetary gear train (200), the second - stage planetary gear train (300), and multi - mode shifting operations, the hub motor (100) is enabled to function as an electromechanical brake execution motor simultaneously; The electromechanical brake input gear (410), the gear end is meshed and connected with the differential output gear (360), and is used to transmit the torque output by the hub motor (100) under the braking condition; The brake disc (430) is fixedly connected to the hub flange of the wheel unit (500); The electromechanical brake execution mechanism (420); mainly consists of a ball - screw mechanism, a brake caliper, a return spring, and a brake clamping force sensor. The ball - screw mechanism is used to convert the rotational motion of the electromechanical brake input gear (410) into the linear motion of the ball nut, thereby actuating the brake caliper to clamp the brake disc (430). The brake caliper is equipped with brake pads to clamp the brake disc (430). When not working, there is a braking gap with the brake disc (430). The return spring is used for the brake caliper to retract after the braking command ends to cancel the braking. The brake clamping force sensor is used to monitor the braking clamping force of the braking system (400) in real - time, providing a reference for the multi - mode shifting operation timing. When the vehicle is in the braking condition, the electromechanical brake input gear (410) transmits the torque output by the hub motor (100) under the braking condition to the electromechanical brake execution mechanism (420), enabling it to actuate the brake caliper to clamp the brake disc (430).

5. The multi-mode integrated redundant drive and brake integrated electric wheel system according to claim 4, characterized in that The rotational direction reference system and working modes include: Define the rotational direction reference system. When the wheel unit (500) moves forward in the positive direction, its own rotation direction around the rotation axis is the positive direction. When the electromechanical brake input gear (410) rotates in the reverse direction, the electromechanical brake actuator (420) clamps the brake disc (430). The working modes of the multi-mode integrated redundant drive and brake integrated electric wheel system are mainly divided into a drive mode, a driving brake mode, a reverse brake mode, and a parking brake mode. Among them, the driving brake mode is a multi-mode driving brake mode, which works under the braking conditions during driving. It can be switched to three modes: a pure electric braking mode, an active braking mode, and a compound braking mode according to different usage scenarios. Among them, the pure electric braking mode is mainly for medium and high-speed cruise speed regulation and relatively gentle braking deceleration conditions. The active braking mode is mainly for short-term braking, emergency braking conditions during low-speed driving, and braking conditions during short-term waiting for traffic lights in complex urban traffic scenarios, as well as braking conditions when the on-vehicle power battery has a high charge and the energy recovery charging efficiency is low and high-power regenerative braking cannot be performed. The compound braking mode is mainly for braking conditions when the on-vehicle power battery has a low charge and maximum energy recovery is required, and long-distance braking with a large braking intensity.

6. The multi-mode integrated redundant drive and brake integrated electric wheel system according to claim 5, characterized in that The control method of the drive mode includes: Drive mode, which works under driving conditions. The power characteristic of the in-wheel motor works in the first quadrant, providing driving torque for the vehicle. At this time, the first-stage shift mechanism (250) is in the 2nd and 4th gears, and the second-stage shift mechanism (350) is in the 2nd gear. At this time, the spline hub of the differential input gear (340) and the spline hub of the first-stage differential ring gear (230) are locked and connected with the locking sleeve and remain stationary. At the same time, the constant-speed sleeve (240) is disengaged from the spline hub of the first-stage planet carrier (220) and the spline hub of the first-stage differential ring gear (230). Then the first-stage planet carrier (220) can rotate normally. At the same time, the second-stage planet carrier (320) is disengaged from the locking sleeve and can rotate normally, and transmits the driving torque of the in-wheel motor (100) to make the wheel unit (500) rotate.

7. The multi-mode integrated redundant drive and brake integrated electric wheel system according to claim 5, characterized in that, The control method of the reverse brake mode includes: Reverse braking mode, which works under the braking condition during the reverse process. The power characteristic of the in-wheel motor operates in the third quadrant, and the in-wheel motor (100) rotates in reverse. At this time, the first-stage shifting mechanism (250) is in the 2nd and 4th gears, and the second-stage shifting mechanism (350) is in the 1st gear. At this time, the spline hub of the differential input gear (340) is locked and connected to the locking engagement sleeve and remains stationary, and the spline hub of the first-stage differential ring gear (230) is disengaged from the locking engagement sleeve and can rotate normally. At the same time, the constant-speed engagement sleeve (240) is disengaged from the spline hub of the first-stage planet carrier (220) and the spline hub of the first-stage differential ring gear (230). Then, the first-stage planet carrier (220) can rotate in a different direction and at a different speed from the first-stage differential ring gear (230). At the same time, the second-stage planet carrier (320) is disengaged from the locking engagement sleeve and can rotate normally. At this time, the in-wheel motor (100) serves as the energy source for both the reverse rotation of the wheel unit (500) and the braking work of the braking system (400). Since the electromechanical braking actuator (420) gradually clamps the brake disc (430), it is difficult for the energy output by the in-wheel motor (100) to flow towards the reverse rotation of the wheel unit (500), but instead, it flows to the electromechanical braking actuator (420) to a greater extent, prompting it to further clamp the brake disc (430), forming a braking force increasing effect. When releasing the brake, only the output power of the in-wheel motor (100) needs to be reduced so that the energy flowing to the electromechanical braking actuator (420) is not sufficient to overcome the elastic force of the return spring, thereby automatically retracting and separating the brake pads.

8. The multi-mode integrated redundant drive and brake integrated electric wheel system according to claim 5, characterized in that, The parking braking mode control method includes: Park brake mode, which works under the park brake condition. At this time, the vehicle speed is zero, and the power characteristic of the in-wheel motor works in the first quadrant. The in-wheel motor (100) rotates forward. First, the first-stage shifting mechanism (250) is in the 2nd and 3rd gears, and the second-stage shifting mechanism (350) is in the 1st gear. At this time, the spline hub of the differential input gear (340) is locked and connected to the locking engagement sleeve and remains stationary, and the spline hub of the first-stage differential ring gear (230) is disengaged from the locking engagement sleeve and can rotate normally. At the same time, the constant-speed engagement sleeve (240) is disengaged from the spline hub of the first-stage planet carrier (220) and the spline hub of the first-stage differential ring gear (230). Then, the first-stage planet carrier (220) can rotate in a different direction and at a different speed from the first-stage differential ring gear (230). The second-stage planet carrier (320) is locked and connected to the locking engagement sleeve and remains stationary, ensuring that the wheel unit (500) cannot rotate. At this time, the in-wheel motor (100) serves as the energy source for the braking system (400) to perform braking work. After the electromechanical brake actuator (420) quickly clamps the brake disc (430), the first-stage park brake redundancy is formed. Subsequently, the first-stage shifting mechanism (250) is switched to the 1st and 3rd gears, and the second-stage shifting mechanism (350) is switched to the 2nd gear, so that the first-stage planetary gear train (200) and the second-stage planetary gear train (300) are all self-locked and remain stationary. The in-wheel motor (100) is turned off to form the second-stage park brake redundancy. When releasing the brake, only need to switch the first-stage shifting mechanism (250) back to the 2nd and 3rd gears, and the second-stage shifting mechanism (350) back to the 1st gear. At this time, the in-wheel motor (100) does not supply energy, and due to the action of the return spring, the brake block of the electromechanical brake actuator (420) automatically retracts and separates from the brake disc (430), and at the same time drives the electromechanical brake input gear (410) to rotate, finally making the in-wheel motor (100) idle (the energy recovery is small and can be ignored).

9. The multi-mode integrated redundant drive and brake integrated electric wheel system according to claim 5, characterized in that, The control method of the service brake mode includes: Pure electric braking mode: The power characteristic of the in-wheel motor works in the fourth quadrant. Using the drag torque of the in-wheel motor (100) to provide braking torque for the whole vehicle braking. At this time, the first-stage shifting mechanism (250) is in the 2nd and 4th gears, and the second-stage shifting mechanism (350) is in the 2nd gear. At this time, the spline hub of the differential input gear (340) and the spline hub of the first-stage differential ring gear (230) are locked and connected to the locking engagement sleeve and remain stationary. At the same time, the constant-speed engagement sleeve (240) is disengaged from the spline hub of the first-stage planet carrier (220) and the spline hub of the first-stage differential ring gear (230). Then, the first-stage planet carrier (220) can rotate normally. At the same time, the second-stage planet carrier (320) is disengaged from the locking engagement sleeve and can rotate normally, enabling the wheel unit (500) to drive the in-wheel motor (100) to recover braking energy; In the active braking mode, the power characteristic of the in-wheel motor operates in the first quadrant, and the in-wheel motor (100) rotates forward. At this time, the first-stage shifting mechanism (250) is in the 1st and 4th gears, and the second-stage shifting mechanism (350) is in the 1st gear. At this time, the spline hub of the differential input gear (340) is locked and connected to the locking engagement sleeve and remains stationary, and the spline hub of the first-stage differential ring gear (230) is disengaged from the locking engagement sleeve and can rotate normally. At the same time, the constant-speed engagement sleeve (240) is connected to the spline hub of the first-stage planet carrier (220) and the spline hub of the first-stage differential ring gear (230), so that the first-stage sun gear (210), the first-stage planet carrier (220), and the first-stage differential ring gear (230) can rotate at the same speed and in the same direction. The second-stage planet carrier (320) is disengaged from the locking engagement sleeve and can rotate normally. At this time, the in-wheel motor (100) simultaneously serves as the energy source for the forward rotation drive of the wheel unit (500) and the braking work of the braking system (400). Since the electromechanical braking actuator (420) gradually clamps the brake disc (430), it is difficult for the energy output by the in-wheel motor (100) to flow to the forward rotation drive of the wheel unit (500), but instead flows to the electromechanical braking actuator (420) to a greater extent, prompting it to further clamp the brake disc (430), forming a braking force increasing effect. When releasing the brake, only the output power of the in-wheel motor (100) needs to be reduced so that the energy flowing to the electromechanical braking actuator (420) is not sufficient to overcome the elastic force of the return spring, thereby causing the brake pad to automatically retract and separate from the brake disc (430); Compound braking mode, the power characteristic of the in-wheel motor operates in the fourth quadrant. The remaining kinetic energy of the vehicle drives each transmission mechanism through the rotation of the wheel unit (500) to supply energy for the energy recovery of the in-wheel motor (100) and the braking work of the braking system (400). First, the first-stage shift mechanism (250) is in the 2nd and 4th gears, and the second-stage shift mechanism (350) is in the 3rd gear. At this time, the spline hub of the differential input gear (340) is disengaged from the locking engagement sleeve and can rotate normally. The spline hub of the first-stage differential ring gear (230) is locked and connected to the locking engagement sleeve and remains stationary. At the same time, the constant-velocity engagement sleeve (240) is disengaged from the spline hub of the first-stage planet carrier (220) and the spline hub of the first-stage differential ring gear (230). Then, the first-stage planet carrier (220) can rotate in a different direction and at a different speed from the first-stage differential ring gear (230). The second-stage planet carrier (320) is disengaged from the locking engagement sleeve and can rotate normally. The remaining kinetic energy of the vehicle will drive the in-wheel motor (100) for energy recovery to achieve electric braking, and at the same time drive the electromechanical braking input gear (410) to rotate, so that the electromechanical braking actuator (420) clamps the brake disc (430) to achieve frictional braking, and the magnitude of the braking clamping force is detected in real time by the braking clamping force sensor. When the braking clamping force reaches the maximum value but the braking task is still not completed, but at this time the electromechanical braking input gear (410) can no longer rotate further. Then, the first-stage shift mechanism (250) remains in the 2nd and 4th gears, and the second-stage shift mechanism (350) switches to the 4th gear, so that the spline hub of the first-stage differential ring gear (230) is disengaged from the locking engagement sleeve and can rotate normally. The remaining kinetic energy of the vehicle not only provides energy for the braking work of the braking system (400), but also provides energy for the energy recovery of the in-wheel motor (100) through two different torque transmission paths, forming multi-stage braking redundancy. When releasing the brake, only need to increase the electric braking power of the in-wheel motor (100). At the same time, the remaining kinetic energy of the vehicle is continuously decreasing, so that the energy flowing to the electromechanical braking actuator (420) is further reduced and is not enough to overcome the elastic force of the return spring, so that the brake block automatically retracts and separates from the brake disc (430).

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