Rear wheel steering device, powertrain, and vehicle

Abstract

The present application provides a rear wheel steering device, a powertrain, and a vehicle. The rear wheel steering device comprises a steering motor, a locking clutch, a lead screw tie rod, and a steering motor controller. The steering motor controller is configured to drive the steering motor to rotate, and, via the locking clutch, drive the lead screw tie rod to realize rear wheel steering of the vehicle. The steering motor controller is further configured to, upon completion of the rear wheel steering, drive the steering motor to rotate and output a torque, so as to limit the rotation angle of the locking clutch to less than a preset angle. The rear wheel steering device provided by the present application uses the steering motor to compensate for the locking torque of the locking clutch, thereby ensuring reliable vehicle driving and reducing the power consumption of the steering motor.

Description

Rear wheel steering gear, power assembly and vehicle

[0001] This application claims priority to the Chinese patent application No. 202411346564.0, filed on September 25, 2024, with the State Intellectual Property Office of China, with the title of “Rear wheel steering gear, power assembly and vehicle”, the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the technical field of vehicles, in particular to a rear wheel steering gear, a power assembly and a vehicle. BACKGROUND

[0003] The rear wheel steering gear is used to control the steering of the rear wheels of the vehicle, so as to reduce the mass center side slip angle of the vehicle during steering, reduce the steady-state overshoot of the vehicle yaw rate, and realize smooth steering. During the steering process of the vehicle, the rear wheel steering gear is needed to limit the steering of the rear wheels to ensure the normal driving of the vehicle. SUMMARY

[0004] The present application provides a rear wheel steering gear, a power assembly and a vehicle. The rear wheel steering gear compensates for the locking torque of the locking clutch through the steering motor, so as to ensure the reliable driving of the vehicle and reduce the power consumption of the steering motor.

[0005] In a first aspect, the present application provides a rear wheel steering gear, which comprises a steering motor, a locking clutch, a screw cross rod and a steering motor controller. The steering motor controller is used to drive the steering motor to rotate and drive the screw cross rod to realize the steering of the rear wheels of the vehicle through the locking clutch. The steering motor controller is also used to drive the steering motor to rotate and output torque to limit the rotation angle of the locking clutch to be less than a preset angle after the steering of the rear wheels is completed.

[0006] The steering motor controller of the rear wheel steering gear provided by the present application is used to drive the steering motor to rotate after the steering of the rear wheels is completed in response to a first control signal. The first control signal is used to indicate that the reaction force of the rear wheels on the locking clutch exceeds the locking force of the locking clutch on the screw cross rod.

[0007] The rear wheel steering gear provided by the present application drives the steering motor to rotate to drive the locking clutch to rotate and drive the screw cross rod to displace along the axial direction when realizing the steering of one or more rear wheels of the vehicle. The rear wheel steering gear provided by the present application also locks the screw cross rod through the locking clutch to limit the swing of one or more rear wheels of the vehicle during the driving of the vehicle, so as to avoid the unintended steering of one or more rear wheels of the vehicle and ensure the smooth driving of the vehicle. At this time, the steering motor can be in a non-working state to save power consumption.

[0008] When the reaction force of the one or more rear wheels on the locking clutch exceeds the locking force of the locking clutch on the tie rod, the rear wheel steering device provided by the application further drives the steering motor to output torque through the steering motor controller to limit the rotation angle of the locking clutch to be less than a preset angle. In this way, the axial displacement of the tie rod can be limited, thereby limiting the swing of the one or more rear wheels and ensuring smooth driving of the vehicle.

[0009] The rear wheel steering device provided by the application can make the steering motor be in a non-working state to save power consumption through the control of the steering motor controller on the steering motor. When the rear wheels of the vehicle are subjected to a large impact, the steering motor is driven to intervene in time to compensate for the locking force of the locking clutch on the tie rod, thereby ensuring smooth driving of the vehicle. The rear wheel steering device provided by the application reduces the frequency of intervention of the steering motor in limiting the steering of the rear wheels through the control of the steering motor controller on the steering motor, thereby reducing the power consumption of the steering motor, controlling the heating of the steering motor, and prolonging the service life of the steering motor.

[0010] In an implementation, the rear wheel steering device comprises a sensor, and the steering motor controller is configured to obtain the reaction force according to the axial displacement of the tie rod detected by the sensor, and generate the first control signal when the reaction force is greater than the locking force.

[0011] In the implementation, the rear wheel steering device provided by the application comprises a sensor. The sensor is configured to detect the axial displacement of the tie rod. The steering motor controller is configured to receive the axial displacement of the tie rod indicated by the detection signal output by the sensor, calculate the reaction force of the one or more rear wheels on the locking clutch, and generate the first control signal to drive the steering motor to output torque when the reaction force is greater than the locking force of the locking clutch on the tie rod, so as to limit the rotation angle of the locking clutch to be less than a preset angle.

[0012] In an implementation, the steering motor controller is configured to integrate the axial displacement of the tie rod indicated by the detection signal output by the sensor to calculate the reaction force of the one or more rear wheels on the locking clutch.

[0013] In an implementation, the steering motor controller is configured to calculate the reaction force according to the axial displacement indicated by the detection signal, and generate the first control signal when the reaction force is greater than the locking force.

[0014] In the present implementation, the detection signal output by the sensor is sent directly or indirectly to the steering motor controller, and the steering motor controller judges and generates a first control signal by itself to indicate that the reaction force of the one or more rear wheel pairs of locking clutches exceeds the locking force of the locking clutches on the screw tie rod. The steering motor controller subsequently drives the steering motor to output torque in response to the first control signal generated by itself to limit the angle of rotation of the locking clutches to be less than a preset angle.

[0015] In an implementation, the steering motor controller is configured to control the torque output by the steering motor to increase with the amount of axial displacement of the screw tie rod during the process of driving the steering motor to output torque in response to the first control signal.

[0016] In the present implementation, the steering motor controller integrates the amount of axial displacement of the screw tie rod indicated by the detection signal to calculate the magnitude of the reaction force formed by the one or more rear wheel pairs of locking clutches. The greater the speed of change of the axial displacement of the screw tie rod indicated by the detection signal, the greater the reaction force formed by the one or more rear wheel pairs of locking clutches. The steering motor controller adjusts the torque output by the steering motor by calculating the speed of change of the axial displacement of the screw tie rod to ensure that the sum of the torque output by the steering motor and the locking force is greater than or equal to the reaction force formed by the one or more rear wheel pairs of locking clutches. This avoids the phenomenon of insufficient torque output by the steering motor.

[0017] In an implementation, the steering motor controller is configured to drive the locking clutches to rotate and control the angle of rotation of the locking clutches to be within a preset angle during the process of driving the steering motor to output torque in response to the first control signal.

[0018] In the present implementation, when the impact force of the one or more rear wheel pairs of locking clutches is too large in some scenarios, it can cause the locking clutches to rotate rapidly, resulting in the phenomenon that the angle of rotation of the locking clutches exceeds the preset angle during the process of the steering motor controller driving the steering motor to output torque. At this time, the steering motor controller also drives the steering motor to drive the locking clutches to rotate to return the angle of rotation of the locking clutches to within the preset angle, thereby limiting the swing angle of the one or more rear wheels of the vehicle and ensuring smooth driving of the vehicle.

[0019] In an implementation, the steering motor controller is configured to calculate the angle of rotation of the locking clutches according to the amount of axial displacement of the screw tie rod.

[0020] In the present implementation, the steering motor controller can calculate the rotation angle of the locking clutch based on the transmission path of the locking clutch to the cross rod of the lead screw according to the axial displacement of the cross rod of the lead screw indicated by the detection signal of the sensor output after receiving the detection signal of the sensor output. After calculating the rotation angle of the locking clutch after being impacted by one or more rear wheels, the steering motor controller can drive the steering motor to rotate the locking clutch back to within the preset angle if the rotation angle of the locking clutch exceeds the preset angle.

[0021] In an implementation, the steering motor controller is configured to output a fault signal according to the axial displacement of the cross rod of the lead screw, and the fault signal is configured to indicate that the locking force of the locking clutch is lower than the preset minimum locking force.

[0022] In the present implementation, the steering motor controller calculates the impact force of the locking clutch by one or more rear wheels and the rotation angle of the locking clutch, respectively. If the impact force calculated by the steering motor controller is lower than the preset minimum locking force of the locking clutch and the locking clutch rotates, the steering motor controller can output a fault signal based on the calculation result. The fault signal is configured to indicate that the locking force of the locking clutch is lower than the preset minimum locking force, so as to directly or indirectly prompt the user that the locking clutch currently has the phenomenon of insufficient locking force, thereby maintaining or replacing the locking clutch and ensuring the reliable operation of the rear wheel steering device of the present application.

[0023] In an implementation, the steering motor controller is configured to drive the steering motor to continuously output torque to limit the rotation angle of the locking clutch to be less than the preset angle when outputting the fault signal.

[0024] In the present implementation, during the process of prompting the user that the locking clutch currently has the phenomenon of insufficient locking force, the steering motor controller also drives the steering motor to continuously output torque to limit the rotation angle of the locking clutch to be less than the preset angle because the locking force of the locking clutch cannot effectively limit the displacement of the cross rod of the lead screw. Thus, the rear wheel steering device of the present application can limit the rotation angle of the locking clutch by the steering motor when the locking force of the locking clutch is insufficient, so as to ensure that the swing angle of the rear wheel is small and the vehicle can travel stably.

[0025] In an implementation, the steering motor controller is configured to prolong the time length of driving the steering motor to rotate to limit the rotation angle of the locking clutch in response to a second control signal, and the second control signal is configured to indicate that the frequency of the steering motor controller in response to the first control signal is greater than the preset frequency.

[0026] In the present implementation, the steering motor controller can be regarded as the vehicle running in a section with large road impact if the steering motor output torque is frequently driven. The steering motor controller can avoid the steering motor frequently starting by prolonging the time of the steering motor output torque. On the basis of ensuring the vehicle to smoothly pass through the section with large road impact, the number of times of large load impact on the steering motor due to frequent starting is reduced, the steering motor is protected, and the service life is prolonged.

[0027] In a second aspect, the present application provides a power assembly, the power assembly comprising the steering motor controller in the rear wheel steering device and a drive motor, the steering motor controller being configured to receive high-voltage direct current and invert the high-voltage direct current into three-phase alternating current to drive the drive motor to rotate and output torque to drive the wheel to rotate.

[0028] The steering motor controller in the rear wheel steering device according to the first aspect of the present application is integrated on the control circuit board of the power assembly, which can simplify the overall structure of the power assembly and the steering motor controller of the rear wheel steering device, occupy less space, and make the structure of the vehicle more compact.

[0029] In a third aspect, the present application provides a vehicle, the vehicle comprising a vehicle controller, a steering motor, a locking clutch, and a screw tie rod, the steering motor being configured to drive the screw tie rod to steer the rear wheel of the vehicle through the locking clutch, and the vehicle controller being configured to drive the steering motor to rotate and output torque to limit the rotation angle of the locking clutch to be less than a preset angle after the rear wheel of the vehicle is steered.

[0030] In the vehicle provided by the present application, the vehicle controller of the vehicle integrates the steering motor controller, the number of parts of the rear wheel steering device is reduced, the installation space inside the vehicle is saved, and the steering motor controller and other controllers can work in coordination with each other, and the control speed of the rear wheel steering locking is improved.

[0031] In an implementation manner of the vehicle provided by the present application, the vehicle controller is configured to drive the steering motor to rotate after the rear wheel of the vehicle is steered in response to a third control signal, and the third control signal is configured to indicate that the reaction force of the locking clutch on the rear wheel of the vehicle exceeds the locking force of the locking clutch on the screw tie rod.

[0032] In the vehicle provided by the present application, the vehicle controller of the vehicle integrates the steering motor controller, the vehicle controller has stronger signal processing capability, can process the third signal more quickly, and thus controls the steering drive motor to more quickly complete the locking after the rear wheel is steered.

[0033] In another implementation manner of the vehicle provided by the present application, the vehicle comprises a sensor, and the vehicle controller is configured to obtain the reaction force according to the axial displacement of the screw tie rod detected by the sensor.

[0034] The vehicle provided in the application has a vehicle controller with stronger signal processing capability, which can process sensor signals more quickly, so as to calculate the reaction force according to the axial displacement of the screw cross rod more quickly, and provide faster results for subsequent processing.

[0035] In another implementation of the vehicle provided in the application, the vehicle controller is configured to control the torque output by the steering motor to increase with the increase of the axial displacement of the screw cross rod during the process of driving the steering motor to output torque in response to the third control signal.

[0036] In the vehicle provided in the application, the vehicle controller has stronger signal processing capability, which can control the torque output by the steering motor to increase with the increase of the axial displacement of the screw cross rod more quickly, so as to better control the locking of the rear wheel after the steering motor assists the rear wheel to steer, and ensure the timeliness of the locking.

[0037] In another implementation of the vehicle provided in the application, the vehicle controller is configured to drive the steering motor to rotate to limit the angle of rotation of the locking clutch to be less than the preset angle in response to the fourth control signal, and the fourth control signal is configured to indicate that the steering angle of the front wheel of the vehicle exceeds the preset steering angle.

[0038] In the vehicle provided in the application, the vehicle controller can also obtain the information of the steering angle of the front wheel in time. Generally, the steering angle of the rear wheel has a certain matching relationship with the steering angle of the front wheel. The vehicle controller can control the steering angle of the rear wheel according to the steering angle of the front wheel, and synchronously control the angle of rotation of the steering motor of the rear wheel to assist the locking clutch within a limited range. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the application, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0040] FIG. 1 is a schematic diagram of the architecture of the vehicle provided in an embodiment of the application;

[0041] FIG. 2 is a schematic diagram of the structure of the rear wheel steering device and the rear wheel provided in an embodiment of the application;

[0042] FIG. 3 is a schematic diagram of the structure of the rear wheel steering device provided in an embodiment of the application;

[0043] FIG. 4 is a schematic diagram of the cross-sectional structure of the rear wheel steering device provided in an embodiment of the application;

[0044] Fig. 5 is a schematic diagram of a cross-sectional structure of the transmission mechanism at A in Fig. 4;

[0045] Fig. 6 is a schematic diagram of a partial structure of a rear wheel steering gear provided in an embodiment of the present application;

[0046] Fig. 7 is a schematic diagram of an exploded structure of a locking clutch provided in an embodiment of the present application;

[0047] Fig. 8 is a schematic diagram of an assembled structure of a locking clutch provided in an embodiment of the present application;

[0048] Fig. 9 is a schematic diagram of a working flow of a rear wheel steering gear provided in an embodiment of the present application;

[0049] Fig. 10 is a schematic diagram of a first control logic of a steering motor controller provided in an embodiment of the present application;

[0050] Fig. 11 is a schematic diagram of a relationship between a reaction force of one or more locking clutches of rear wheels and a locking force of the locking clutches on a cross rod of a lead screw provided in an embodiment of the present application;

[0051] Fig. 12 is a schematic diagram of a second control logic of a steering motor controller provided in an embodiment of the present application;

[0052] Fig. 13 is a schematic diagram of a working flow of a rear wheel steering gear provided in another embodiment of the present application;

[0053] Fig. 14 is a schematic diagram of a third control logic of a steering motor controller provided in an embodiment of the present application;

[0054] Fig. 15 is a schematic diagram of a fourth control logic of a steering motor controller provided in an embodiment of the present application;

[0055] Fig. 16 is a schematic diagram of an application scenario of a powertrain provided in an embodiment of the present application;

[0056] Fig. 17 is a schematic diagram of an architecture of a vehicle provided in another embodiment of the present application;

[0057] Fig. 18 is a schematic diagram of a fifth control logic of a steering motor controller provided in an embodiment of the present application.

[0058] 1000-vehicle; 1001-frame; 1002-rear wheel; 1003-front wheel; 1004-knuckle; 800-vehicle controller; 900-front wheel steering gear; 500-power assembly; 501-driving motor; 200-rear wheel steering gear; 10-steering motor; 11-motor shaft; 20-transmission mechanism; 21-input end; 211-transmission wheel; 22-output end; 221-transmission member; 2211-sleeve; 30-screwed rod; 31-threaded section; 32-rolling ball; 40-locking clutch; 41-driving shaft; 42-moving member; 43-output shaft; 44-housing; 50-steering motor controller; 60-sensor. DETAILED DESCRIPTION

[0059] The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0060] The present application provides a rear wheel steering gear, which comprises a steering motor, a locking clutch and a steering motor controller. The steering motor controller is configured to drive the steering motor to rotate and drive the screwed rod through the locking clutch to realize the steering of one or more rear wheels of the vehicle. The steering motor controller is further configured to drive the steering motor to rotate to limit the rotation angle of the locking clutch to be less than a preset angle after the steering of the rear wheels is completed. The rotation of the steering motor after the steering of the rear wheels is completed is not in response to the steering angle, but in response to an instruction to limit the rotation of the locking clutch to exceed a certain angle. In response to a first control signal, the steering motor controller is configured to drive the steering motor to rotate after the steering of the rear wheels is completed. The first control signal is configured to indicate that the reaction force of the one or more rear wheels on the locking clutch exceeds the locking force of the locking clutch on the screwed rod. The rear wheel steering gear provided by the present application can realize the steering of the rear wheels, while reducing the power consumption of the steering motor and prolonging the service life of the steering motor.

[0061] The present application provides a power assembly, which comprises a driving motor and a steering motor controller. The steering motor controller is configured to receive high-voltage direct current and invert it into three-phase alternating current to supply the driving motor to output torque to drive the rotation of the wheels.

[0062] The steering motor controller is configured to control the driving motor to output power and drive the steering motor to rotate and drive the screw cross rod through the lock clutch to steer the rear wheels of the vehicle, and the steering motor controller is further configured to drive the steering motor to output torque in response to the first control signal to limit the angle of rotation of the lock clutch to be less than a preset angle; the first control signal is configured to indicate that the reaction force of the rear wheels on the lock clutch exceeds the locking force of the lock clutch on the screw cross rod. The power assembly provided by the application can provide driving force and realize rear wheel steering, and has low power consumption and long service life.

[0063] The application provides a vehicle, which comprises a rear wheel and the rear wheel steering device provided by the application. The rear wheel steering device is configured to drive one or more rear wheels to steer.

[0064] Alternatively, the application provides a vehicle, which comprises a rear wheel and the power assembly provided by the application. The power assembly is configured to output power and drive one or more rear wheels to steer.

[0065] The vehicle provided by the application can not only steer the rear wheels but also run stably, and has low power consumption and long service life.

[0066] The application provides another vehicle, which comprises a vehicle controller, a rear wheel steering device and one or more rear wheels. The rear wheel steering device comprises a steering motor and a lock clutch. The steering motor is configured to drive one or more rear wheels of the vehicle to steer through the lock clutch to drive the screw cross rod. The vehicle controller is configured to output a first control signal to indicate the steering motor to rotate to limit the angle of rotation of the lock clutch to be less than a preset angle; the first control signal is configured to indicate that the reaction force of the one or more rear wheels on the lock clutch exceeds the locking force of the lock clutch on the screw cross rod. The vehicle provided by the application can not only steer the rear wheels but also run stably, and has low power consumption and long service life.

[0067] Please refer to the schematic diagram of the architecture of the vehicle 1000 provided by an embodiment of the application shown in FIG. 1.

[0068] As shown in FIG. 1, the vehicle 1000 provided by the application comprises a rear wheel steering device 200. The rear wheel steering device 200 is configured to be fixed to the vehicle frame 1001 and in driving connection with one or more rear wheels 1002 of the vehicle 1000. The rear wheel steering device 200 is configured to drive the one or more rear wheels 1002 of the vehicle 1000 to steer, thereby increasing the steering angle control range of the vehicle 1000 and reducing the phenomenon of understeering or oversteering of the vehicle 1000.

[0069] For example, in some scenarios, when the vehicle 1000 needs to turn or reverse with a small turning radius, the front wheels 1003 and the rear wheels 1002 of the vehicle 1000 can be controlled to rotate in opposite directions, so as to reduce the turning radius and improve the flexibility of the vehicle 1000. In other scenarios, when the vehicle 1000 needs to turn a corner at a certain speed, the front wheels 1003 and the rear wheels 1002 of the vehicle 1000 can be controlled to rotate in the same direction, so as to reduce the side slip angle of the center of mass of the vehicle 1000, reduce the steady-state overshoot of the yaw rate of the vehicle 1000, and thus enhance the handling stability of the vehicle 1000.

[0070] Please refer to FIG. 2 and FIG. 3, FIG. 2 is a structural schematic diagram of the rear wheel steering device 200 and the rear wheel 1002 provided in an embodiment of the present application; and FIG. 3 is a structural schematic diagram of the rear wheel steering device 200 provided in an embodiment of the present application.

[0071] As shown in FIG. 2 and FIG. 3, the rear wheel steering device 200 provided by the present application comprises a steering motor 10, a transmission mechanism 20 and a screw cross tie 30, wherein the steering motor 10 is configured to drive the screw cross tie 30 to move through the transmission mechanism 20, so as to drive one or more rear wheels 1002 to steer. The steering motor 10 is fixed to the vehicle frame 1001, and the motor shaft 11 of the steering motor 10 is parallel to the axial direction of the rear wheel 1002. The screw cross tie 30 is slidingly connected to the vehicle frame 1001 along the axial direction parallel to the rear wheel 1002, and the screw cross tie 30 extends along the axial direction parallel to the rear wheel 1002, and at least one axial end of the screw cross tie 30 is connected to one rear wheel 1002 through a steering knuckle 1004. The transmission mechanism 20 is configured to drivingly connect the steering motor 10 and the screw cross tie 30. The transmission mechanism 20 comprises an input end 21 and an output end 22, the input end 21 is configured to receive the driving force of the steering motor 10, and the output end 22 is configured to drive the screw cross tie 30 to displace along the axial direction of the screw cross tie 30, so as to drive the rear wheel 1002 to deflect relative to the vehicle frame 1001, and realize the steering of the rear wheel 1002.

[0072] In the illustrated embodiment, the screw cross tie 30 is drivingly connected to one rear wheel 1002 through one steering knuckle 1004 at each axial end of the screw cross tie 30, and the transmission mechanism 20 is configured to receive the driving force of the steering motor 10 to drive the screw cross tie 30 to displace along the axial direction, so that the screw cross tie 30 drives the two rear wheels 1002 to steer.

[0073] In an embodiment, the output end 22 comprises a transmission member 221, the transmission member 221 is drivingly connected to the screw cross tie 30, the transmission member 221 receives the driving force of the input end 21, and transmits the driving force to the screw cross tie 30 to drive the screw cross tie 30 to displace along the axial direction of the screw cross tie 30.

[0074] In an embodiment, the transmission member 221 comprises a threaded sleeve 2211, which is sleeved on the outer circumferential surface of the screw cross tie 30, and the inner circumferential surface of the threaded sleeve 2211 is engaged with the outer circumferential surface of the screw cross tie 30. Specifically, please refer to FIG. 4 and FIG. 5, wherein FIG. 4 is a schematic diagram of the cross-sectional structure of the rear wheel steering gear 200 provided in an embodiment of the present application; and FIG. 5 is a schematic diagram of the cross-sectional structure of the transmission mechanism 20 at A in FIG. 4. As shown in FIG. 4 and FIG. 5, the screw cross tie 30 comprises a threaded segment 31, and the threaded sleeve 2211 is sleeved on the threaded segment 31, and the internal thread on the inner circumferential surface of the threaded sleeve 2211 is engaged with the thread on the threaded segment 31. The threaded sleeve 2211 receives the driving force of the input end 21 to rotate relative to the screw cross tie 30 about the axis of the screw cross tie 30 and drive the screw cross tie 30 to displace along the axial direction of the screw cross tie 30, so that the rear wheel 1002 is steered. It can be understood that the threaded sleeve 2211 is used in cooperation with the threaded segment 31 of the screw cross tie 30 to ensure the reliability of the displacement of the screw cross tie 30 along the axial direction thereof driven by the transmission member 221.

[0075] In an embodiment, the input end 21 comprises a transmission wheel 211, the axis of the transmission wheel 211 is parallel to the axis of the screw cross tie 30, and the transmission wheel 211 is arranged in a spaced manner with the screw cross tie 30 along the radial direction of the screw cross tie 30. The transmission wheel 211 is used to drivingly connect the motor shaft 11 of the steering motor 10 and is used to drivingly connect the outer circumferential surface of the threaded sleeve 2211. Thus, the rotation of the motor shaft 11 of the steering motor 10 can drive the transmission wheel 211 to rotate and drive the threaded sleeve 2211 to rotate, so that the screw cross tie 30 can displace along the axial direction thereof. That is, the rotation of the motor shaft 11 of the steering motor 10 is converted into the linear motion of the screw cross tie 30 along the axial direction thereof by the transmission wheel 211 and the threaded sleeve 2211.

[0076] In an embodiment, the transmission mode between the transmission wheel 211 and the threaded sleeve 2211 can comprise any one or a combination of multiple modes such as belt transmission, chain transmission, gear transmission, rack and pinion transmission, etc., to ensure that the driving force of the transmission wheel 211 can be reliably transmitted to the threaded sleeve 2211, and the threaded sleeve 2211 can rotate about the axis of the screw cross tie 30 to drive the screw cross tie 30 to displace along the axial direction thereof, which is not particularly limited in the present application.

[0077] In an embodiment, the diameter of the transmission wheel 211 is smaller than the diameter of the screw sleeve 2211, so that a speed reduction effect can be formed between the transmission wheel 211 and the screw sleeve 2211 from the input end 21 to the output end 22. The transmission wheel 211 and the screw sleeve 2211 can be used to adjust the speed and torque of the driving force output by the steering motor 10, and transmit the adjusted driving force to the screw cross rod 30. Specifically, during the rotation of the motor shaft 11 of the steering motor 10, the transmission wheel 211 can reduce the speed of the screw sleeve 2211 and amplify the driving force output by the steering motor 10, so as to effectively ensure the axial displacement of the screw cross rod 30 driven by the screw sleeve 2211.

[0078] Please refer to the partial structure diagram of the rear wheel steering device 200 provided in an embodiment of the present application shown in FIG. 6.

[0079] As shown in FIG. 6, the rear wheel steering device 200 provided by the present application further comprises a locking clutch 40, which is used to drivingly connect the motor shaft 11 of the steering motor 10 and the screw cross rod 30. During the rotation of the steering motor 10, the locking clutch 40 is used to drive the screw cross rod 30 to move along the axial direction, so as to drive the rear wheel 1002 to steer. Before the rotation of the steering motor 10, the locking clutch 40 is used to limit the displacement of the screw cross rod 30 along the axial direction of the screw cross rod 30.

[0080] Specifically, please refer to FIG. 7 and FIG. 8, wherein FIG. 7 is an exploded structure diagram of the locking clutch 40 provided in an embodiment of the present application; and FIG. 8 is an assembled structure diagram of the locking clutch 40 provided in an embodiment of the present application.

[0081] As shown in FIG. 7 and FIG. 8, the lock clutch 40 comprises a driving shaft 41, a movable element 42, an output shaft 43 and a housing 44. The driving shaft 41 is parallel to the axis of the tie rod 30, and the driving shaft 41 is used to drive the motor shaft 11 of the steering motor 10 and the movable element 42. The housing 44 is annular, and the movable element 42 is sleeved in the housing 44. The output shaft 43 is located on the side of the movable element 42 away from the steering motor 10, and the axis of the output shaft 43 is parallel to the axis of the tie rod 30. The output shaft 43 is sleeved in the inner ring of the transmission wheel 211 and fixed with the transmission wheel 211. The movable element 42 can move radially towards or away from the output shaft 43 to lock or release the output shaft 43. During the rotation of the steering motor 10, the driving shaft 41 drives the movable element 42 to move radially towards the output shaft 43 and abut against the output shaft 43 to lock the output shaft 43 under the drive of the motor shaft 11, so as to drive the transmission wheel 211 to rotate to drive the tie rod 30 to move axially along the axis of the tie rod 30. Before the rotation of the steering motor 10, the movable element 42 moves radially away from the output shaft 43 to release the output shaft 43 and limit the rotation of the output shaft 43, so as to limit the axial displacement of the tie rod 30.

[0082] The rear wheel steering device 200 provided in the present application further comprises a steering motor controller 50, which is in communication connection with the steering motor 10. The steering motor controller 50 is used to drive the steering motor 10 to rotate and drive the tie rod 30 through the lock clutch 40 to realize the steering of one or more rear wheels 1002 of the vehicle 1000. The steering motor controller 50 is also used to drive the steering motor 10 to output torque in response to a first control signal to limit the angle of rotation of the lock clutch 40 to be less than a preset angle. The first control signal is used to indicate that the reaction force of the one or more rear wheels 1002 on the lock clutch 40 exceeds the locking force of the lock clutch 40 on the tie rod 30.

[0083] The rear wheel steering gear 200 provided by the present application drives the steering motor 10 to drive the locking clutch 40 to rotate to drive the screw cross rod 30 to displace along the axial direction when steering one or more rear wheels 1002 of the vehicle 1000. It should be noted that the rotation of the locking clutch 40 refers to the rotation of the output shaft 43. The rear wheel steering gear 200 provided by the present application also locks the screw cross rod 30 by the locking clutch 40 to limit the swing of one or more rear wheels 1002 of the vehicle 1000 during the driving of the vehicle 1000, so as to avoid the unintended steering of one or more rear wheels 1002 of the vehicle 1000 and ensure the smooth driving of the vehicle 1000. At this time, the steering motor 10 can be in a non-working state to save power consumption. That is, when the vehicle 1000 drives on uneven road surface to cause the rear wheel 1002 to be impacted by the ground to produce unintended steering, the rear wheel 1002 will drive the screw cross rod 30 to displace along the axial direction of the screw cross rod 30 in the reverse direction, and thus drive the transmission mechanism 20 to drive the output shaft 43 to rotate in the reverse direction. The present application can receive the reaction force from the rear wheel 1002 by the output shaft 43 in the locking clutch 40, and limit the rotation of the output shaft 43 by the movable piece 42 to apply a locking force to the screw cross rod 30, so as to limit the axial displacement amount of the screw cross rod 30, and further limit the angle of the unintended steering of the rear wheel 1002.

[0084] When the reaction force of one or more rear wheels 1002 of the vehicle 1000 on the locking clutch 40 exceeds the locking force of the locking clutch 40 on the screw cross rod 30, that is, when the reaction force received by the output shaft 43 in the locking clutch 40 exceeds the abutting force of the movable piece 42 on the output shaft 43, the rear wheel steering gear 200 provided by the present application also drives the steering motor 10 to output torque by the steering motor controller 50 to limit the rotation angle of the locking clutch 40 to be less than a preset angle. Specifically, the steering motor controller 50 is configured to drive the motor shaft 11 of the steering motor 10 to rotate to drive the movable piece 42 to move along the radial direction of the output shaft 43 and further abut against the output shaft 43 in response to the first control signal, that is, when the reaction force of one or more rear wheels 1002 of the vehicle 1000 on the locking clutch 40 exceeds the locking force of the locking clutch 40 on the screw cross rod 30. Thus, the rotation of the output shaft 43 due to the reaction force of the screw cross rod 30 is limited. Thus, the axial displacement amount of the screw cross rod 30 is limited to avoid the swing angle of one or more rear wheels 1002 of the vehicle 1000 being too large, and ensure the smooth driving of the vehicle 1000.

[0085] The rear wheel steering device 200 provided by the present application limits the unintended steering of one or more rear wheels by the locking clutch 40, and in combination with the control of the steering motor 10 by the steering motor controller 50, the steering motor 10 can be in a non-working state to save power consumption. When the rear wheel 1002 of the vehicle 1000 is subjected to a large impact, the steering motor controller 50 drives the steering motor 10 to intervene in time to compensate for the locking force of the locking clutch 40 on the screw cross link 30.

[0086] The steering motor controller 50 changes the state of the locking clutch 40 by driving the steering motor 10, so that the locking clutch 40 provides a locking force to the screw cross link 30 when the output shaft 43 is released, and the locking clutch 40 drives the output shaft 43 to actively rotate or limits the output shaft 43 to passively rotate when the output shaft 43 is locked. Because the unintended steering of the rear wheel 1002 does not need to be limited by the self-locking of the screw cross link 30, it is beneficial to improve the transmission efficiency between the transmission mechanism 20 and the screw cross link 30, reduce the power consumption of the steering motor 10, and reduce the size of the steering motor 10.

[0087] The steering motor 10 does not need to output torque at all times during vehicle travel to limit the axial displacement of the screw cross link 30. The rear wheel steering device 200 provided by the present application reduces the frequency of intervention of the steering motor 10 to limit the steering of the rear wheel 1002 by the steering motor controller 50 controlling the steering motor 10, which can reduce the power consumption of the steering motor 10, control the heating of the steering motor 10, and prolong the service life of the steering motor 10.

[0088] In an embodiment, a plurality of balls 32 are arranged between the inner circumferential surface of the screw sleeve 2211 and the threaded segment 31 of the screw cross link 30, and the plurality of balls 32 are arranged in a circumferential direction of the screw cross link 30 and are in contact between the inner circumferential surface of the screw sleeve 2211 and the outer circumferential surface of the threaded segment 31. It can be understood that the plurality of balls 32 can reduce the friction between the screw sleeve 2211 and the screw cross link 30, thereby further improving the transmission efficiency of the rear wheel steering device 200 provided by the present application.

[0089] In an embodiment, the rear wheel steering device 200 provided by the present application includes a sensor 60, and the steering motor controller 50 is configured to calculate whether to generate a first control signal according to a detection signal output by the sensor 60. The detection signal is used to indicate the amount of axial displacement of the screw cross link 30.

[0090] Specifically, in the embodiment, the sensor 60 includes a displacement sensor, which can be fixed on the cross rod 30 or fixed on the frame 1001 corresponding to the position of the cross rod 30. The displacement sensor is used to directly detect the axial displacement of the cross rod 30. In other embodiments, the sensor 60 can include an angle sensor, which is fixed on the rear wheel 1002 and used to detect the swing angle of the rear wheel 1002. The angle sensor can indirectly obtain the axial displacement of the cross rod 30 by detecting the swing angle of the rear wheel 1002. In some embodiments, the angle sensor is fixed on the transmission wheel 211 of the transmission mechanism 20 and used to detect the rotation angle of the transmission wheel 211. Because the transmission wheel 211 is in transmission connection with the cross rod 30, the angle sensor can indirectly obtain the axial displacement of the cross rod 30 by detecting the rotation angle of the transmission wheel 211. That is, the detection signal of the sensor 60 can directly or indirectly indicate the axial displacement of the cross rod 30. The sensor 60 is in communication connection or electrical connection with the steering motor controller 50, and the sensor 60 is used to transmit the detection signal to the steering motor controller 50. The steering motor controller 50 is used to receive the axial displacement of the cross rod 30 indicated by the detection signal output by the sensor 60, calculate the size of the reaction force formed by one or more rear wheels 1002 on the lock clutch 40, and form a first control signal to drive the steering motor 10 to output torque when the reaction force is greater than the locking force of the lock clutch 40 on the cross rod 30, so as to limit the angle of rotation of the lock clutch 40 to be less than a preset angle.

[0091] Please refer to the working flow diagram of the rear wheel steering device 200 provided in an embodiment of the application shown in FIG. 9, and the first control logic diagram of the steering motor controller 50 provided in an embodiment of the application shown in FIG. 10.

[0092] As shown in FIGS. 9 and 10, during the driving of the vehicle 1000, the specific working process of the rear wheel steering device 200 provided in the application by driving the steering motor 10 through the steering motor controller 50 includes:

[0093] S500, the steering motor controller 50 is used to calculate whether to generate a first control signal according to the detection signal output by the sensor 60;

[0094] It can be understood that, in the transmission path from the screw rod 30 to the lock clutch 40, due to the assembly gap between the lock clutch 40 and the screw rod 30, when the vehicle 1000 runs on uneven road surface and causes the rear wheel 1002 to be impacted, the rear wheel 1002 can reversely drive the screw rod 30 to axially displace within the assembly gap. At this time, even if the lock clutch 40 has the ability to reliably lock the screw rod 30, the screw rod 30 can still axially move within the assembly gap. The sensor 60 can detect the axial displacement amount of the screw rod 30 based on this. The steering motor controller 50 is configured to integrate the axial displacement amount of the screw rod 30 indicated by the detection signal output by the screw rod 30 to calculate the magnitude of the reaction force of the one or more rear wheels 1002 on the lock clutch 40.

[0095] Specifically, in the present embodiment, the steering motor controller 50 integrates the axial displacement amount of the screw rod 30 to obtain the acceleration of the screw rod 30, and calls the preset mass of the screw rod 30 to calculate the magnitude of the reaction force of the one or more rear wheels 1002 on the lock clutch 40. In another embodiment, the steering motor controller 50 can integrate the axial displacement amount of the screw rod 30 to calculate the acceleration of the screw rod 30, and compare it with the preset acceleration threshold of the screw rod 30 to determine the magnitude of the reaction force of the one or more rear wheels 1002 on the lock clutch 40.

[0096] The steering motor controller 50 is also configured to determine the magnitude of the reaction force and the locking force of the lock clutch 40 on the screw rod 30 to determine whether to generate the first control signal. When the reaction force of the one or more rear wheels 1002 on the lock clutch 40 does not exceed the locking force of the lock clutch 40 on the screw rod 30, the lock clutch 40 does not rotate following the axial displacement of the screw rod 30, and the steering motor controller 50 does not generate the first control signal. At this time, the screw rod 30 can be reliably locked only by the lock clutch 40, and the steering motor 10 does not need to participate in locking the screw rod 30 by the lock clutch 40.

[0097] For example, please refer to the relationship between the reaction force of the one or more rear wheels 1002 on the lock clutch 40 and the locking force of the lock clutch 40 on the screw rod 30 in an embodiment of the present application shown in FIG. 11.

[0098] Specifically, the screw rod tie rod 30 is in the transmission path of the transmission mechanism 20 drivingly connected to the locking clutch 40, and the transmission mechanism 20 and the screw rod tie rod 30 and the interior of the transmission mechanism 20 and the screw rod tie rod 30 respectively have assembly clearances. The transmission mechanism 20 and the screw rod tie rod 30 and the interior of the transmission mechanism 20 and the screw rod tie rod 30 also respectively have self-locking forces. When one or more rear wheels 1002 receive road surface impact, the screw rod tie rod 30 axially displaces based on the above-mentioned assembly clearances. When the wheel end impact on the screw rod tie rod 30 exceeds the self-locking force between the transmission mechanism 20 and the screw rod tie rod 30 and the interior of the transmission mechanism 20 and the screw rod tie rod 30, the locking force of the locking clutch 40 is used to limit the axial displacement of the screw rod tie rod 30.

[0099] Because the transmission efficiency of the rear wheel steering gear 200 of the present application is high, the self-locking force between the transmission mechanism 20 and the screw rod tie rod 30 and the interior of the transmission mechanism 20 and the screw rod tie rod 30 is relatively small, as shown in the example of FIG. 11, which can be 0.2kN.

[0100] The preset locking force of the locking clutch 40 is set to 10kN. When the steering motor controller 50 calculates that the reaction force formed by one or more rear wheels 1002 on the locking clutch 40 does not exceed 10kN according to the amount of axial displacement of the screw rod tie rod 30, it indicates that the locking clutch 40 has the ability to reliably lock the screw rod tie rod 30. At this time, only the locking clutch 40 is used to lock the screw rod tie rod 30 to limit the axial displacement of the screw rod tie rod 30. That is, the axial displacement of the screw rod tie rod 30 caused by being driven in the opposite direction by one or more rear wheels 1002 is only limited by the locking clutch 40.

[0101] In some embodiments, when the wheel end impact on the screw rod tie rod 30 is large, the amount of axial displacement of the screw rod tie rod 30 can exceed the amount of axial displacement allowed by the assembly clearances between the transmission mechanism 20 and the screw rod tie rod 30 and the interior of the transmission mechanism 20 and the screw rod tie rod 30. At this time, the screw rod tie rod 30 further drives the locking clutch 40 to rotate. The detection signal output by the sensor 60 can be used to directly indicate that the reaction force on the screw rod tie rod 30 is greater than the locking force of the locking clutch 40.

[0102] S1000, the steering motor controller 50 is configured to calculate the reaction force according to the amount of axial displacement indicated by the detection signal, and generate a first control signal when the reaction force is greater than the locking force;

[0103] S1500, the steering motor controller 50 is configured to drive the steering motor 10 to output torque to limit the angle of rotation of the locking clutch 40 to be less than a preset angle in response to the first control signal.

[0104] When the reaction force of the one or more rear wheels 1002 on the lock clutch 40 is greater than the locking force of the lock clutch 40 on the cross rod 30, the lock clutch 40 can rotate following the axial displacement of the cross rod 30, so that the angle of rotation of the lock clutch 40 is greater than the preset angle. At this time, it indicates that the locking force of the lock clutch 40 on the cross rod 30 is insufficient, and the steering motor controller 50 generates a first control signal and responds to the first control signal to drive the steering motor 10 to output torque. The angle of rotation of the lock clutch 40 is limited within the preset angle by the intervention of the steering motor 10 to compensate for the locking force of the lock clutch 40 on the cross rod 30, thereby limiting the axial displacement of the cross rod 30. For example, when the steering motor controller 50 calculates that the reaction force of the one or more rear wheels 1002 on the lock clutch 40 is greater than 10 kN according to the axial displacement of the cross rod 30, the lock clutch 40 cannot reliably lock the cross rod, and at this time the steering motor controller 50 drives the steering motor 10 to output torque to compensate for the locking force of the lock clutch 40 on the cross rod 30.

[0105] It should be noted that the output torque of the steering motor 10 has two states. In one state, the motor shaft 11 of the steering motor 10 is fixed and does not rotate, but the torque is large. In another state, the motor shaft 11 of the steering motor 10 rotates, and the torque is large. The steering motor controller 50 selects the state of the output torque of the steering motor 10 according to the size of the calculated reaction force to limit the angle of rotation of the lock clutch 40 to be less than the preset angle, and to compensate for the locking force of the lock clutch 40 on the cross rod 30. Thus, the motor shaft 11 of the steering motor 10 does not need to rotate all the time to compensate for the locking force of the lock clutch 40 on the cross rod 30, thereby avoiding the phenomenon of heating caused by the long-time rotation of the motor shaft 11 of the steering motor 10, and prolonging the service life of the steering motor 10.

[0106] When the steering motor controller 50 calculates and analyzes that the reaction force of the one or more rear wheels 1002 on the lock clutch 40 exceeds the locking force of the lock clutch 40 on the cross rod 30, the steering motor controller 50 knows that the lock clutch 40 cannot reliably lock the cross rod 30. Then the steering motor controller 50 responds to the first control signal generated by itself to drive the steering motor 10 to output torque to limit the angle of rotation of the lock clutch 40 to be less than the preset angle, and to cooperate with the lock clutch 40 to reliably lock the cross rod 30.

[0107] In one embodiment, the steering motor controller 50 is configured to control the torque output by the steering motor 10 to increase as the speed of change of the axial displacement indicated by the detection signal increases during the process of driving the steering motor 10 to output torque in response to the first control signal.

[0108] When the vehicle 1000 is running on uneven road, and the reaction force of the one or more rear wheels 1002 on the lock-up clutch 40 is greater than the locking force of the lock-up clutch 40 on the screw tie rod 30, the steering motor controller 50 responds to the first control signal generated by itself, and drives the steering motor 10 to output torque to limit the rotation angle of the lock-up clutch 40 to be less than the preset angle. In addition, the steering motor controller 50 can also adjust the output torque of the steering motor 10 according to the change speed of the axial displacement of the screw tie rod 30.

[0109] Specifically, the steering motor controller 50 integrates the axial displacement of the screw tie rod 30 indicated by the detection signal to calculate the reaction force of the one or more rear wheels 1002 on the lock-up clutch 40. The greater the change speed of the axial displacement of the screw tie rod 30 indicated by the detection signal, the greater the reaction force of the one or more rear wheels 1002 on the lock-up clutch 40. If it is necessary to ensure the smooth running of the vehicle 1000, the greater the reaction force of the one or more rear wheels 1002 on the lock-up clutch 40, the greater the locking force of the lock-up clutch 40 on the screw tie rod 30. When the reaction force of the one or more rear wheels 1002 on the lock-up clutch 40 is greater than the preset locking force of the lock-up clutch 40, and the change speed of the axial displacement of the screw tie rod 30 detected by the sensor 60 is faster, the steering motor controller 50 can control the steering motor 10 to output greater torque correspondingly, to ensure that the sum of the torque output by the steering motor 10 and the preset locking force of the lock-up clutch 40 is greater than or equal to the reaction force of the one or more rear wheels 1002 on the lock-up clutch 40. Avoid the phenomenon that the torque output by the steering motor 10 is insufficient, which leads to the phenomenon that the swing angle of the rear wheel 1002 is too large.

[0110] In an embodiment, the steering motor controller 50 is configured to drive the lock-up clutch 40 to rotate to control the rotation angle of the lock-up clutch 40 within the preset angle during the process of driving the steering motor 10 to output torque in response to the first control signal.

[0111] It can be understood that when the impact force of the one or more rear wheels 1002 on the lock-up clutch 40 is too large in some scenarios, it can cause the lock-up clutch 40 to rotate rapidly, so that the rotation angle of the lock-up clutch 40 exceeds the preset angle during the process of driving the steering motor 10 to output torque by the steering motor controller 50. At this time, the steering motor controller 50 also drives the steering motor 10 to drive the lock-up clutch 40 to rotate to return the rotation angle of the lock-up clutch 40 to within the preset angle, thereby limiting the swing angle of the one or more rear wheels 1002 of the vehicle 1000 and ensuring the smooth running of the vehicle 1000.

[0112] For example, in one embodiment, the preset angle of the lock-up clutch 40 is 5°. When the lock-up clutch 40 rotates at an angle greater than 5° under the axial displacement of the cross rod 30, the steering motor controller 50 can drive the steering motor 10 to rotate the lock-up clutch 40 in the opposite direction to return the rotation angle of the lock-up clutch 40 to within 5°.

[0113] In one embodiment, the steering motor controller 50 is configured to calculate the rotation angle of the lock-up clutch 40 according to the axial displacement indicated by the detection signal output by the sensor 60. In this embodiment, after receiving the detection signal output by the sensor 60, the steering motor controller 50 can calculate the rotation angle of the lock-up clutch 40 based on the transmission path of the lock-up clutch 40 to the cross rod 30 according to the axial displacement of the cross rod 30 indicated by the detection signal. Specifically, the steering motor controller 50 calculates the size of the reaction force of the one or more rear wheels 1002 on the lock-up clutch 40 according to the axial displacement of the cross rod 30, and calls a mapping relationship between the reaction force of the one or more rear wheels 1002 on the lock-up clutch 40 and the rotation angle of the lock-up clutch 40 to obtain the actual rotation angle of the lock-up clutch 40 at this time.

[0114] That is, the step S500 "the steering motor controller 50 is configured to calculate whether to generate the first control signal according to the detection signal output by the sensor 60" can be implemented as follows:

[0115] S500a, the steering motor controller 50 is configured to calculate the rotation angle of the lock-up clutch 40 according to the axial displacement indicated by the detection signal, and generate the first control signal when the rotation angle is greater than the preset angle.

[0116] When the actual rotation angle of the locking clutch 40 exceeds the preset angle, the steering motor controller 50 can drive the steering motor 10 to rotate the locking clutch 40 back to within the preset angle, so as to ensure the smooth driving of the vehicle 1000. After the steering motor controller 50 calculates the actual rotation angle of the locking clutch 40 according to the axial displacement of the tie rod 30 indicated by the detection signal output by the sensor 60, the actual rotation angle of the locking clutch 40 is compared with the preset angle. When the actual rotation angle of the locking clutch 40 is less than or equal to the preset angle of the locking clutch, it indicates that the locking clutch 40 can reliably limit the axial displacement of the tie rod 30. That is, at this time, the axial displacement of the tie rod 30 can be limited only by the locking clutch 40, so as to limit the swing of the rear wheel 1002, and further ensure the smooth driving of the vehicle 1000. When the actual rotation angle of the locking clutch 40 is greater than the preset angle of the locking clutch 40, it indicates that the locking force of the locking clutch 40 on the tie rod 30 is insufficient, and the output shaft 43 of the locking clutch 40 can be driven to rotate in the opposite direction by the tie rod 30. In order to ensure the smooth driving of the vehicle 1000, the steering motor controller 50 generates a first control signal, so as to subsequently intervene the output torque in the rear wheel steering gear 200 through the steering motor 10, so as to drive the steering motor 10 to rotate the locking clutch 40 back to within the preset angle, and further limit the axial displacement of the tie rod 30 (for reference, see the second control logic diagram of the steering motor controller 50 provided in an embodiment of the present application shown in FIG. 12).

[0117] For reference, see the working flow diagram of the rear wheel steering gear 200 provided in another embodiment of the present application shown in FIG. 13, and the third control logic diagram of the steering motor controller 50 provided in an embodiment of the present application shown in FIG. 14.

[0118] In an embodiment, the steering motor controller 50 is configured to calculate whether to output a fault signal according to the displacement indicated by the detection signal output by the sensor 60, wherein the fault signal is used to indicate that the locking force of the locking clutch 40 is lower than the preset minimum locking force.

[0119] That is, before the step S500 “the steering motor controller 50 is configured to calculate whether to generate a first control signal according to the detection signal output by the sensor 60”, it can further include:

[0120] S300, the steering motor controller 50 is configured to calculate whether to output a fault signal according to the axial displacement indicated by the detection signal, and the fault signal is used to indicate that the locking force of the locking clutch 40 is lower than the preset minimum locking force.

[0121] It can be understood that the steering motor controller 50 calculates the reaction force generated by the one or more rear wheels 1002 on the locking clutch 40 and the rotation angle of the locking clutch 40 according to the axial displacement of the cross rod 30 indicated by the detection signal output by the sensor 60. Then, the mapping relationship between the reaction force generated by the one or more rear wheels 1002 on the locking clutch 40 and the locking force of the locking clutch 40 on the cross rod 30 is compared, and the mapping relationship between the rotation angle of the locking clutch 40 and the preset angle is compared.

[0122] If the reaction force calculated by the steering motor controller 50 is less than or equal to the locking force of the locking clutch 40, the steering motor controller 50 generates a first control signal and drives the steering motor 10 to output torque to limit the rotation angle of the locking clutch 40 to be less than the preset angle, thereby limiting the axial displacement of the cross rod 30. If the reaction force calculated by the steering motor controller 50 is less than or equal to the locking force of the locking clutch 40, but the rotation angle of the locking clutch 40 exceeds the preset angle, it indicates that the locking clutch 40 has a fault, the actual locking force of the locking clutch 40 is less than the preset locking force, and the locking clutch 40 cannot reliably lock the cross rod 30.

[0123] At this time, the steering motor controller 50 can output a fault signal to directly or indirectly prompt the user that the locking clutch 40 currently has a locking force deficiency, thereby facilitating maintenance or replacement of the locking clutch 40 and ensuring reliable operation of the rear wheel steering device 200. If the reaction force calculated by the steering motor controller 50 is less than or equal to the locking force of the locking clutch 40, and the rotation angle of the locking clutch 40 is less than or equal to the preset angle of the locking clutch 40, it indicates that the locking clutch 40 can reliably lock the cross rod 30.

[0124] In an embodiment, the steering motor controller 50 is configured to output a fault signal and drive the steering motor 10 to continuously output torque to limit the rotation angle of the locking clutch 40 to be less than the preset angle. It can be understood that, in the process of prompting the user that the locking clutch 40 currently has a locking force deficiency, because the locking force of the locking clutch 40 cannot effectively limit the displacement of the cross rod 30, the steering motor controller 50 of the present application can also drive the steering motor 10 to continuously output torque to limit the rotation angle of the locking clutch 40 to be less than the preset angle. Thus, the rear wheel steering device 200 can continuously limit the rotation angle of the locking clutch 40 by the steering motor 10 when the locking force of the locking clutch 40 is insufficient, so as to ensure that the swing angle of the rear wheel 1002 is small and the vehicle 1000 can travel smoothly.

[0125] Please refer to the fourth control logic diagram of the steering motor controller 50 provided in an embodiment of the present application shown in Figure 15.

[0126] As shown in Figure 15, the steering motor controller 50 is configured to extend the time period of driving the steering motor 10 to rotate in response to the second control signal in response to the first control signal for limiting the angle of rotation of the lock-up clutch 40; wherein the second control signal is configured to instruct the steering motor controller 50 to respond to the frequency of the first control signal being greater than a preset frequency. That is, when the frequency of the first control signal to which the steering motor controller 50 responds is greater than the preset frequency, the steering motor controller 50 also responds to the second control signal to extend the time period of driving the steering motor 10 to rotate.

[0127] It can be understood that if the steering motor controller 50 frequently drives the steering motor 10 to output torque, it can be considered that the vehicle 1000 is running in a section with relatively large road impact. In this scenario, the steering motor controller 50 can avoid the steering motor 10 from frequently starting by extending the time period of the steering motor 10 outputting torque. On the basis of ensuring the vehicle 1000 to smoothly pass through the section with relatively large road impact, the number of times of large load impact on the steering motor 10 due to frequent starting is reduced, thereby protecting the steering motor 10 and prolonging the service life.

[0128] Please refer to the application scenario diagram of the power assembly 500 provided in an embodiment of the present application shown in Figure 16.

[0129] In an embodiment, the power assembly includes the steering motor controller provided in the first aspect and the drive motor, and the steering motor controller is further configured to receive high-voltage direct current and invert it into three-phase alternating current to supply the drive motor to operate and output torque to drive the wheels to rotate.

[0130] As shown in Figure 16, the power assembly 500 provided by the present application includes a drive motor 501 and a steering motor controller 50. The drive motor 501 is fixed to the vehicle frame 1001 and is configured to be drivingly connected to the wheels of the vehicle 1000. In an embodiment, the power assembly 500 is configured to drive the rear wheels 1002 of the vehicle 1000 alone, and at this time, the drive motor 501 and the steering motor controller 50 of the power assembly 500 are fixed close to the position of the rear wheels 1002. The steering motor controller 50 is in communication connection with the drive motor 501 and is also configured to be in communication connection with the steering motor 10. The steering motor controller 50 is configured to drive the drive motor 501 to output power to make the vehicle run, and the steering motor controller 50 is also configured to drive the steering motor 10 to rotate and drive the lead screw tie rod 30 through the lock-up clutch 40 to realize the steering of the rear wheels 1002 of the vehicle 1000.

[0131] In an embodiment, the steering motor controller 50 is further configured to drive the steering motor 10 to output a torque to limit an angle of rotation of the lock-up clutch 40 to be less than a preset angle in response to the first control signal. The first control signal is configured to indicate that a reaction force of the rear wheels 1002 on the lock-up clutch 40 exceeds a lock-up force of the lock-up clutch 40 on the screw tie rod 30.

[0132] It can be understood that, in the embodiment, the power assembly 500 is configured to drive the drive motor 501 to output power by the steering motor controller 50. The power assembly 500 is further configured to drive the steering motor 10 to limit the angle of rotation of the lock-up clutch 40 to be less than the preset angle by the steering motor controller 50. That is, the steering motor controller 50 of the power assembly 500 is configured to drive the steering motor 10 of the rear wheel steering device 200 to control the steering of one or more of the rear wheels 1002 of the vehicle 1000 and limit the angle of rotation of the lock-up clutch 40 to be less than the preset angle by driving the steering motor 10.

[0133] The power assembly 500 can also be configured to drive the front wheels 1003 of the vehicle simultaneously. In some embodiments, the power assembly 500 is configured to drive the front wheels 1003 of the vehicle individually. The above-mentioned embodiments do not affect the driving control of the steering motor 10 by the steering motor controller 50 of the power assembly 500.

[0134] The steering motor controller 50 is integrated with the power assembly 500. Because the power assembly 500 is located close to the steering motor 10 in the vehicle 1000, the integration of the steering motor controller 50 and the power assembly 500 in the rear wheel steering device 200 simplifies the overall structure of the power assembly 500 and the rear wheel steering device 200 and makes the structure of the vehicle 1000 more compact.

[0135] In an embodiment, the rear wheel steering device 200 comprises a sensor 60, and the steering motor controller 50 is configured to calculate whether to generate the first control signal according to a detection signal output by the sensor 60. The detection signal is configured to indicate an axial displacement of the screw tie rod 30.

[0136] In an embodiment, the steering motor controller 50 is configured to integrate the axial displacement of the screw tie rod 30 indicated by the detection signal output by the sensor 60 to calculate a size of the reaction force of one or more of the rear wheels 1002 on the lock-up clutch 40.

[0137] In an embodiment, the steering motor controller 50 is configured to calculate the reaction force according to the axial displacement indicated by the detection signal and generate the first control signal when the reaction force is greater than the lock-up force.

[0138] In one embodiment, the steering motor controller 50 is configured to increase the speed of the change of the torque outputted by the steering motor 10 in response to the first control signal in accordance with the amount of the axial displacement indicated by the detection signal.

[0139] In one embodiment, the steering motor controller 50 is configured to rotate the lock-up clutch 40 in response to the first control signal in the process of driving the steering motor 10 to output torque, so as to control the angle of rotation of the lock-up clutch 40 within a preset angle.

[0140] In one embodiment, the steering motor controller 50 is configured to calculate the angle of rotation of the lock-up clutch 40 according to the amount of the axial displacement indicated by the detection signal outputted by the sensor 60.

[0141] In one embodiment, the steering motor controller 50 is configured to calculate whether to output a fault signal according to the amount of the axial displacement indicated by the detection signal outputted by the sensor 60, the fault signal being used to indicate that the locking force of the lock-up clutch 40 is lower than a preset minimum locking force.

[0142] In one embodiment, the steering motor controller 50 is configured to output the fault signal and drive the steering motor 10 to continuously output torque so as to limit the angle of rotation of the lock-up clutch 40 to be less than a preset angle.

[0143] In one embodiment, the steering motor controller 50 is configured to, in the process of driving the steering motor 10 to rotate in response to the first control signal, also extend the time length of driving the steering motor 10 to rotate in response to the second control signal so as to limit the angle of rotation of the lock-up clutch 40; the second control signal is used to indicate that the frequency of the response of the steering motor controller 50 to the first control signal is greater than a preset frequency.

[0144] Please refer to the schematic diagram of the architecture of the vehicle 1000 provided in another embodiment of the present application shown in FIG. 17.

[0145] As shown in FIG. 17, one embodiment provides a vehicle 1000 including a vehicle controller 800, a steering motor 10, a lock-up clutch 40, a rear wheel steering device 200, a screw cross rod 30, and one or more rear wheels 1002. The steering motor 10 is configured to drive the screw cross rod 30 to steer the rear wheels 1002 of the vehicle 1000 through the lock-up clutch 40, and the vehicle controller 800 is configured to drive the steering motor 10 to rotate and output torque after the steering of the rear wheels 1002 of the vehicle 1000 is completed so as to limit the angle of rotation of the lock-up clutch 40 to be less than a preset angle.

[0146] The vehicle controller 800 of the vehicle 1000 integrates the steering motor controller 50, reduces the number of control components of the rear wheel steering gear 200, saves the installation space inside the vehicle 1000, and enables the steering motor controller 50 to work in coordination with other controllers such as the controller of the front wheel steering, the wheel speed sensor, and the like, improves the control speed of the rear wheel 1002 steering lock, and enables the rear wheel 1002 to steer more quickly and stably.

[0147] As shown in FIG. 17, in an implementation of the vehicle 1000, the vehicle controller 800 is configured to drive the steering motor 10 to rotate after the rear wheel 1002 of the vehicle 1000 is steered in response to a third control signal for indicating that the reaction force of the rear wheel 1002 of the vehicle on the lock clutch 40 exceeds the locking force of the lock clutch 40 on the screw cross rod 30.

[0148] The vehicle controller 800 of the vehicle 1000 needs to collect the comparison between the reaction force of the rear wheel 1002 on the lock clutch 40 and the locking force of the lock clutch 40 on the screw cross rod 30 to control the locking of the lock clutch 40. The vehicle controller 800 of the vehicle 1000 integrates the steering motor controller 50, and the vehicle controller 800 has stronger signal processing capability and can quickly process the comparison between the reaction force of the rear wheel 1002 on the lock clutch 40 and the locking force of the lock clutch 40 on the screw cross rod 30, thereby quickly controlling the steering motor 10 to assist in completing the locking of the rear wheel 1002 after steering.

[0149] As shown in FIG. 17, in another implementation of the vehicle 1000, the vehicle 1000 includes a sensor 60, and the vehicle controller 800 is configured to obtain the reaction force according to the axial displacement of the screw cross rod 30 detected by the sensor 60.

[0150] The sensor 60 is configured to measure the axial displacement of the screw cross rod 30 and transmit the axial displacement of the screw cross rod 30 to the vehicle controller 800 for calculating the reaction force. The vehicle controller 800 of the vehicle 1000 has stronger signal processing capability and can quickly process the sensor 60 signal and quickly calculate the reaction force according to the axial displacement of the screw cross rod 30, thereby promoting the lock clutch 40 to be locked to a suitable angle more quickly.

[0151] As shown in FIG. 17, in another implementation of the vehicle 1000, the vehicle controller 800 is configured to control the torque output by the steering motor 10 to increase with the increase of the axial displacement of the screw cross rod 30 during the process of driving the steering motor 10 to output the torque in response to the third control signal.

[0152] The increase of the axial displacement of the screw rod cross tie 30 indicates that the steering angle of the rear wheel 1002 is larger, and a larger torque is required for locking. Since the vehicle controller 800 has stronger signal processing capability, it can control the torque output by the steering motor 10 to increase with the increase of the axial displacement of the screw rod cross tie 30, thereby better controlling the steering motor 10 to assist in locking after the rear wheel 1002 is steered, and ensuring the timeliness of the locking.

[0153] Please refer to the fifth control logic diagram of the steering motor controller 50 provided in an embodiment of the application shown in FIG. 18.

[0154] As shown in FIGS. 17 and 18, in another implementation of the vehicle 1000, the vehicle controller 800 is configured to drive the steering motor 10 to rotate to limit the angle of rotation of the locking clutch 40 to be less than the preset angle in response to a fourth control signal, the fourth control signal being configured to indicate that the steering angle of the front wheel 1003 of the vehicle exceeds a preset steering angle.

[0155] The vehicle 1000 has a front wheel steering device 900, which can monitor the steering angle of the front wheel 1003 in real time. The front wheel steering device 900 is in communication connection with the vehicle controller 800, and the vehicle controller 800 can also obtain the information of the steering angle of the front wheel 1003 in time. Generally, there is a certain matching relationship between the steering angle of the rear wheel 1002 and the steering angle of the front wheel 1003. The vehicle controller 800 can control the steering angle of the rear wheel 1002 according to the steering angle of the front wheel 1003, and synchronously control the steering motor 10 of the rear wheel 1002 to assist in limiting the angle of rotation of the locking clutch 40 within a limited range.

[0156] The steering motor controller 50 is configured to drive the steering motor 10 to rotate to limit the angle of rotation of the locking clutch 40 to be less than the preset angle in response to a fourth control signal. In an embodiment, the fourth control signal can be configured to indicate that the one or more front wheels 1003 of the vehicle 1000 are subjected to an axial reaction force greater than a preset axial reaction force. It can be understood that during the driving of the vehicle 1000, the steering motor controller 50 can control the state of the steering motor 10 based on the size of the axial reaction force formed by the road impact on the one or more front wheels 1003. Specifically, when the axial reaction force formed by the road impact on the one or more front wheels 1003 is greater than the preset axial reaction force, the steering motor controller 50 can drive the steering motor 10 to output a torque to intervene in the locking force of the locking clutch 40 on the screw rod cross tie in advance, thereby limiting the swing of the rear wheel 1002. In this way, it can be avoided that the locking clutch 40 is subjected to an excessive impact force, causing the rotation angle to exceed the preset angle.

[0157] In another embodiment, the fourth control signal can be used to indicate that the steering angle of the one or more front wheels 1003 of the vehicle 1000 exceeds a preset steering angle. During the driving of the vehicle 1000, the steering motor controller 50 can control the state of the steering motor 10 based on whether the steering angle of the one or more front wheels 1003 of the vehicle 1000 exceeds the preset steering angle. Specifically, when the steering angle of the one or more front wheels 1003 of the vehicle 1000 exceeds the preset steering angle, the steering motor controller 50 can drive the steering motor 10 to output a torque to drive the lock-up clutch 40 to rotate reversely in advance, so as to limit the angle of the one or more rear wheels 1002 driving the lock-up clutch 40 to rotate reversely due to the reaction force of the lock-up clutch 40. Thus, it can be avoided that the lock-up clutch 40 is possibly rotated reversely beyond the preset angle due to the steering angle of the vehicle 1000 being too large.

[0158] Obviously, various modifications and changes can be made to the present application without departing from the scope of the present application. Accordingly, it is intended that all such modifications and changes be included within the scope of the application as set forth in the following claims and their equivalents.

Claims

1. A rear wheel steering gear characterized by, The rear wheel steering device comprises a steering motor, a locking clutch, a screw cross tie rod and a steering motor controller, the steering motor controller is used to drive the steering motor to rotate and drive the screw cross tie rod to realize the rear wheel steering of the vehicle through the locking clutch, and the steering motor controller is also used to drive the steering motor to rotate and output torque to limit the rotation angle of the locking clutch to be less than a preset angle after the rear wheel steering is completed.

2. The rear wheel steerer of claim 1, wherein, The steering motor controller is used to drive the steering motor to rotate after the rear wheel steering is completed in response to a first control signal, and the first control signal is used to indicate that the reaction force of the rear wheel on the locking clutch is greater than the locking force of the locking clutch on the screw cross tie rod.

3. The rear wheel steerer of claim 2, wherein, The rear wheel steering device comprises a sensor, and the steering motor controller is used to obtain the reaction force according to the axial displacement of the screw cross tie rod detected by the sensor, and the steering motor controller is used to generate the first control signal when the reaction force is greater than the locking force.

4. The rear wheel steerer according to claim 2 or 3, characterized in that The steering motor controller is used to control the torque output by the steering motor to increase with the increase of the axial displacement of the screw cross tie rod during the process of driving the steering motor to output torque in response to the first control signal.

5. The rear wheel steering gear according to any one of claims 2 to 4, characterized in that The steering motor controller is used to: drive the locking clutch to rotate and control the rotation angle of the locking clutch to be within the preset angle during the process of driving the steering motor to output torque in response to the first control signal.

6. The rear wheel steerer of claim 5, wherein, The steering motor controller is used to: obtain the rotation angle of the locking clutch according to the axial displacement of the screw cross tie rod.

7. The rear wheel steerer according to any one of claims 3-6, characterized in that, The steering motor controller is used to: output a fault signal according to the axial displacement of the screw cross tie rod, and the fault signal is used to indicate that the locking force of the locking clutch is lower than a preset minimum locking force.

8. The rear wheel steerer of claim 7, wherein, The steering motor controller is used to: drive the steering motor to continuously output torque to limit the rotation angle of the locking clutch to be less than the preset angle when the fault signal is output.

9. The rear wheel steering gear according to any one of claims 1 to 8, characterized in that The steering motor controller is used to: extend the time length of driving the steering motor to rotate to limit the rotation angle of the locking clutch in response to a second control signal, and the second control signal is used to indicate that the frequency of the steering motor controller in response to the first control signal is greater than a preset frequency.

10. A powertrain characterized by, The power assembly comprises a driving motor and the steering motor controller in the rear wheel steering device as claimed in claims 1-9, and the steering motor controller is also used to receive high-voltage direct current and invert it into three-phase alternating current to supply the driving motor to operate and output torque to drive the wheels to rotate.

11. A vehicle characterized by comprising: The vehicle comprises a vehicle controller, a steering motor, a locking clutch and a screw cross tie rod, the steering motor is used to drive the screw cross tie rod to realize the rear wheel steering of the vehicle through the locking clutch, and the vehicle controller is used to: drive the steering motor to rotate and output torque to limit the rotation angle of the locking clutch to be less than a preset angle after the rear wheel steering of the vehicle is completed.

12. The vehicle of claim 11, wherein, In response to a third control signal, the vehicle control unit is configured to drive the steering motor to rotate after the rear wheels of the vehicle are steered, the third control signal being configured to indicate that a reaction force of the rear wheels of the vehicle on the locking clutch exceeds a locking force of the locking clutch on the tie rod.

13. The vehicle of claim 12, wherein, The vehicle comprises a sensor, and the vehicle control unit is configured to obtain the reaction force according to an axial displacement of the tie rod detected by the sensor.

14. The vehicle of claim 13, wherein, The vehicle control unit is configured to control the torque output by the steering motor to increase with the axial displacement of the tie rod during the driving of the steering motor in response to the third control signal.

15. The vehicle of any of claims 11-14, wherein, The vehicle control unit is configured to drive the steering motor to rotate in response to a fourth control signal to limit an angle of rotation of the locking clutch to be less than the preset angle, the fourth control signal being configured to indicate that a steering angle of the front wheels of the vehicle exceeds a preset steering angle.

Images