Independent rear-wheel steering structure, suspension, new energy vehicles and control methods

Abstract

The application discloses an independent rear wheel steering structure, suspension, a new energy vehicle and a control method, and belongs to the technical field of new energy vehicle chassis, wherein the independent rear wheel steering structure comprises a lower swing arm or a lower connecting rod and a steering component arranged on the lower swing arm or the lower connecting rod; the steering component is arranged at the lower swing arm or the lower connecting rod of a left rear wheel and a right rear wheel, one end of the steering component is hinged with a steering seat through a ball head component, the other end of the steering component is hinged with the lower swing arm or the lower connecting rod, a rotating driving mechanism is arranged at the lower swing arm or the lower connecting rod, the rotating driving mechanism is connected with a controller, and the steering seat is driven to rotate correspondingly through a connecting rod component.

Description

Technical Field

[0001] This invention relates to the field of new energy vehicle chassis technology, and particularly to an independent rear-wheel steering structure, suspension, new energy vehicles and control methods. Background Technology

[0002] Rear-wheel steering refers to the ability to adjust the angle of the rear wheels in addition to front-wheel steering to assist in steering. This method allows the rear wheels to deflect in the same direction as the front wheels at low speeds and in the opposite direction at high speeds. It improves vehicle agility; at low speeds, such as when parking or making a U-turn, the rear wheels deflecting in the same direction as the front wheels makes the vehicle more maneuverable and reduces the turning radius. It also enhances stability; at high speeds, the rear wheels deflecting in the opposite direction helps improve the vehicle's straight-line stability and responsiveness during lane changes.

[0003] Therefore, some high-performance vehicles, especially new energy vehicles that are being vigorously developed in China, are equipped with both front-wheel and rear-wheel steering systems, also known as four-wheel steering suspension systems. These systems combine the advantages of both front-wheel and rear-wheel steering, automatically adjusting the angles of the front and rear wheels under different speed conditions to achieve optimal handling and safety. They also demonstrate their respective advantages in various usage scenarios.

[0004] However, existing rear-wheel steering structures typically use the integrated steering seat structure of front-wheel steering. Due to the complex structure of the rear wheels and rear axle, multiple components need to be arranged, such as the four-wheel drive system, part of the battery or fuel tank. When arranging the motor and drive structure, unreasonable structural configuration or encroachment on the interior space of the vehicle can easily occur. At the same time, the operation of the rear wheels, especially when the vehicle is running at high speed, requires extremely high stability. Even slight deviations can cause the vehicle to exhibit abnormal postures that exceed the expected control difficulty. In particular, traditional rear-wheel steering structures have several shortcomings in special situations such as slippery roads, abnormal potholes, or tire blowouts. Therefore, more attempts and research are needed for four-wheel steering in new energy vehicles. Summary of the Invention

[0005] The purpose of this invention is to provide an independent rear-wheel steering structure, suspension, new energy vehicle and control method. By improving the rear-wheel steering structure of the vehicle, the invention provides vehicle controllability and enables targeted control in multiple usage scenarios.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] An independent rear-wheel steering structure includes a lower control arm or lower linkage and a steering component arranged on the lower control arm or lower linkage. The steering component is arranged at the lower control arm or lower linkage of the left and right rear wheels. One end is hinged to the steering seat through a ball joint, and the other end is hinged to the lower control arm or lower linkage. A rotation drive mechanism is hinged at the lower control arm or lower linkage. The rotation drive mechanism is connected to a controller and drives the steering seat to rotate accordingly through the linkage component.

[0008] Furthermore, the steering component includes a first link and a second link. The first link is connected to the steering arm of the steering seat via a first ball joint. The other end of the first link is hinged to the second link. The other end of the second link is connected to the lower control arm or the lower link via a second ball joint. A rotation drive mechanism is arranged on the second link.

[0009] Furthermore, the first ball joint is positioned at the lower rear side of the wheel center point as the vehicle moves forward, and the second ball joint is positioned near the lower control arm or lower linkage and the frame mounting structure.

[0010] Furthermore, the second link extends outward at the hinge point with the first link and is provided with a hinge structure. A third ball joint is provided at the lower swing arm or lower link. A drive mechanism is arranged between the third ball joint and the hinge structure. The drive mechanism is used to drive the second link and make it rotate around the second ball joint, so that the steering component constructs a triangular force-bearing structure with the first link and the second link as the framework, and a triangular force-bearing structure with the second link and the drive mechanism as the framework.

[0011] Furthermore, a locking mechanism is arranged at the front end of the second link. The locking mechanism is used to restrict the rotation of the second link and keep the corresponding wheel in a straight-line driving state. The front end of the second link has a V-shaped groove. The locking mechanism includes a locking block and a locking block driving mechanism. The front end of the locking block is provided with a V-shaped protrusion. The front end of the V-shaped protrusion can be embedded in the V-shaped groove.

[0012] A suspension system comprising the aforementioned independent rear-wheel steering configuration.

[0013] A new energy vehicle, including the aforementioned suspension.

[0014] A four-wheel steering control method, applied to the aforementioned independent rear-wheel steering structure, includes:

[0015] The control host obtains the current vehicle speed value V and the front wheel steering angle A through the vehicle's functional components;

[0016] If the driving speed value V is greater than the first set value V1, and the front wheel steering angle value A is greater than the first set value A1, the controller will deflect the rear wheels in the same direction as the front wheel steering angle, and the deflection angle of the rear wheel on the outside of the turn will be greater than the deflection angle of the rear wheel on the inside of the turn.

[0017] Furthermore, if the driving speed value V is less than the second set value V2, and the front wheel steering angle value A is greater than the second set value A2, the controller performs a deflection of the rear wheels in the opposite direction to the front wheel steering angle, and the deflection angle of the rear wheel on the outside of the turn is greater than the deflection angle of the rear vehicle on the inside of the turn.

[0018] If the driving speed value V is negative and the front wheel steering angle value A is greater than the second set value A2, the controller will deflect the rear wheels in the opposite direction to the front wheel steering angle, and the deflection angle of the rear wheel on the outside of the turn will be greater than the deflection angle of the rear vehicle on the inside of the turn.

[0019] A vehicle stability control method, applied to the aforementioned independent rear-wheel steering structure, includes:

[0020] The control host obtains the current vehicle speed value V and the front wheel steering angle A through the vehicle's functional components;

[0021] The control unit senses the current rotational speed of the four tires through the ABS sensors on the wheels;

[0022] When the rotational speed of the left or right front wheel is significantly lower than that of the other three wheels, and the driving speed value V is greater than the third set value V3, and the front wheel steering angle value A is greater than the third set value A3, the controller will deflect the rear wheels in the same direction as the front wheel steering angle.

[0023] When the rotational speed of the left or right rear wheel is significantly lower than that of the other three wheels, and the driving speed value V is greater than the third set value V3, and the front wheel steering angle value A is greater than the third set value A3, the controller will deflect the normal rear wheel in the same direction as the front wheel steering angle.

[0024] Compared with existing technologies, this solution has the following advantages:

[0025] This solution features an independent rear-wheel steering structure, applicable to new energy vehicles. Through electronic control and the vehicle's main unit, it enables steering control of all four wheels, especially the rear wheels. By coordinating the steering control of the front and rear wheels, it allows for high-speed maneuvers and low-speed cornering with small turning radii. This solution employs an independent rear-wheel component structure, meaning the left and right rear wheels use completely independent steering components, which are entirely located at the lower control arm or lower linkage of the rear wheels. A lightweight structure is also used to reduce unsprung mass. Compared to traditional integrated steering systems, this design eliminates the need to encroach on rear chassis space, allowing for precise angle control of the left and right rear wheels. This enables real-time rear-wheel functionality in multiple scenarios, significantly improving the vehicle's driving performance and stability.

[0026] The steering component in this solution is mounted on the lower control arm or lower link, eliminating the need for extensive redesign of the existing vehicle structure. It is implemented through a drive mechanism consisting of a first link, a second link, and a high-precision servo cylinder. The first and second links form a triangular force-bearing structure, as do the second link and the drive mechanism, significantly improving structural stability. The rotational force of the wheels is transferred to the subframe through the structure of the first and second links, reducing the force distribution to the servo cylinder drive mechanism. The large stroke with a small angle configuration improves the accuracy of wheel rotation and the controllability of the servo cylinder drive mechanism. At the same time, locating the entire steering component on the lower control arm or lower link reduces the impact of the vehicle's up-and-down shock-absorbing movement on the steering system, resulting in less interference and more stable operation.

[0027] This solution has a locking mechanism at the end of the second link of the steering component, which can lock the vehicle when the rear wheels are in a straight line during normal driving. This greatly improves the stability of the vehicle and reduces the need for the servo cylinder drive mechanism that controls the steering of the rear wheels to be in standby mode. This reduces its workload and improves its stability and service life.

[0028] This solution is a four-wheel steering control method that achieves multi-scenario application functions by independently controlling the angle of the rear wheels. In particular, by implementing different rear wheel deflection angles for the two rear wheels, it can improve the vehicle's tracking performance and reduce the occurrence of sideslip, oversteer, or understeer when the vehicle is traveling at relatively high speeds. When the vehicle is turning at low speeds or reversing into a parking space, it can improve the vehicle's driving stability, reduce the turning radius, and improve the convenience of turning and entering and exiting parking spaces.

[0029] This solution is a vehicle stability control method, mainly to deal with situations such as wheel abnormalities (e.g., tire blowout) at high speeds. In such situations, the driver is prone to oversteering in the opposite direction due to the pull on one side, which can lead to loss of control or rollover. This solution reduces oversteering and rollover by steering the rear wheels in the same direction as the front wheels, thereby greatly improving stability and controllability in extreme conditions.

[0030] This solution enables differentiated and functional operation in multiple vehicle driving scenarios by allowing completely independent control and adjustment of the rear wheels. It has great potential for widespread adoption and will play a positive role in my country's new energy vehicle technology and application. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the vehicle structure in a preferred embodiment.

[0032] Figure 2 This is a schematic diagram of the rear wheel assembly structure of the vehicle.

[0033] Figure 3 This is a schematic diagram of the layout of the steering components for the right rear wheel.

[0034] Figure 4 This is a schematic diagram of the steering component.

[0035] Figure 5 This is a top view of the steering component.

[0036] Figure 6 This is a simplified structural diagram of the rotating state.

[0037] Figure 7 This is a schematic diagram of the decomposed structure of the locking mechanism.

[0038] Figure 8 This is a schematic diagram of the four-wheel structure of a vehicle in a straight line.

[0039] Figure 9 This is a schematic diagram of the four-wheel structure in its first working state.

[0040] Figure 10 This is a schematic diagram of the four-wheel structure in the second working state.

[0041] Figure 11 This is a schematic diagram of the four-wheel structure in the third working state.

[0042] Figure 12 This is a schematic diagram of the four-wheel structure in the fourth working state. Detailed Implementation

[0043] refer to Figures 1 to 5 A new energy vehicle includes:

[0044] The front wheel assembly includes a left front wheel and a right front wheel, a suspension structure connecting the two wheels and a steering gear 11, the steering gear 11 controlling the rotation direction and angle of the left front wheel and the right front wheel;

[0045] The rear wheel assembly includes a left rear wheel and a right rear wheel, and a suspension structure connecting the two wheels. Steering components 2 are arranged in the suspension structure for independently controlling the rotation direction and angle of the left and right rear wheels.

[0046] The controller, based on the instructions of the vehicle control host, controls the steering components to independently control the rotation direction and angle of the left and right rear wheels;

[0047] A rotation angle sensor is located at the steering component 2 to obtain the current rotation angle value of the left or right rear wheel in real time and feed the rotation angle value back to the vehicle control host.

[0048] Specifically, the four wheels of the vehicle are mounted on the subframe 10 through the suspension structure. The subframe 10 is connected to the body 1 and forms the entire body structure. The left front wheel and the right front wheel receive the driver's control through the steering gear 11, or receive the control of the vehicle control host in the case of intelligent driving, so as to realize the synchronous rotation control of the left front wheel and the right front wheel, thereby controlling the driving direction of the vehicle.

[0049] To achieve steering control of the rear wheels, the left and right rear wheels are connected to the subframe 10 via a lower control arm 12. A ball joint is arranged at the front end of the lower control arm 12, and the ball joint is connected to a steering seat 14. A spring and shock absorber are arranged above the steering seat 14 to achieve the up-and-down shock-absorbing movement of the wheel 13 and to achieve the function of rotating around the ball joint.

[0050] It should be noted that there are several mainstream suspension structures for wheels, such as MacPherson strut suspension, double wishbone suspension, or multi-link suspension. Generally speaking, to implement steering control of the wheels, a rotatable shaft mechanism and a drive mechanism for the vehicle's mounting components (steering seat) to rotate around the shaft are required in the vertical direction. This solution is described using a lower control arm structure, but it does not mean that this solution is limited to the lower control arm structure. Those skilled in the art can also apply this solution to various vehicle suspension structures.

[0051] The independent rear-wheel steering structure includes lower control arms located at the left and right rear wheels. The steering component 2 includes a first link 21 and a second link 22. The first link 21 is connected to the steering arm 15 of the steering seat 14 via a first ball joint. The other end of the first link 21 is hinged to the second link 22, and the other end of the second link 22 is connected to the lower control arm 2 via a second ball joint. The first ball joint is located at the lower rear of the center point of the wheel 13 in the direction of vehicle travel. By positioning the first ball joint behind the vehicle in the forward direction, the steering component 2 can form a traction structure, improving vehicle stability and reducing impacts on the steering component under various conditions. The second ball joint is located near the mounting structure between the lower control arm 12 and the subframe 10. This arrangement maximizes the use of space in the lower control arm 12, extends the length of the first link 21 and the second link 22, reduces the impact of wheel vertical shock absorption, and ensures that the force on the second ball joint is transmitted to the subframe in the shortest possible distance.

[0052] The second link 22 extends outward at the hinge point with the first link 21 and is provided with a hinge structure. A third ball joint is provided at the lower swing arm 12. A high-precision servo cylinder 23 is arranged between the third ball joint and the hinge structure. The servo cylinder 23 is connected to the controller and is used to drive the second link 22 and make it rotate around the second ball joint. In general, the extended second swing arm 22 is used to increase the lever arm, reduce the force on the servo cylinder 23, and make the rotation control more precise and reliable with a larger stroke.

[0053] Therefore, at the lower control arm 12, the steering component 2 is constructed with a triangular force-bearing structure based on the first link 21 and the second link 22, and a triangular force-bearing structure based on the second link 22 and the servo cylinder 23. Through these two triangular force-bearing structures sharing the second link 22, the entire steering component 2 can be subjected to more balanced forces, and the rotation control can be more precise and reliable. At the same time, within the designed rotation angle, the steering component 2 is always arranged within the corresponding spatial frame of the lower control arm and will not intrude into other vehicle body spaces.

[0054] refer to Figure 6In this embodiment, the maximum steering angle of the rear wheel is designed to be ±10° (where red indicates +10° deflection and blue indicates -10° deflection). (It should be noted that, with appropriate structural optimization, the maximum rotation angle can be greater than ±10° as the design standard). The corresponding rotation angle of the second link 22 is 39.16°, so the rotation angle at the second link 22 is magnified by 1.958 times. The first ball joint has a rotation stroke of 22.62 units, corresponding to a stroke of 46.92 units at the front end of the servo cylinder 23, so the stroke of the servo cylinder 23 is magnified by 2.07 times. At the same time, through the force-bearing structure of these two triangles, the impact force of the wheel is mainly transmitted from the second ball joint to the lower control arm 12 and the subframe 10, so that the servo cylinder 23 is distributed with a relatively small force. Therefore, from the perspective of this structure, the working intensity of the servo cylinder 23 can be greatly reduced, and its controllability and stability can be improved.

[0055] refer to Figure 7 In some embodiments, a locking mechanism 3 is arranged at the front end of the second link 22. The locking mechanism 3 is used to restrict the rotation of the second link 22 and keep the corresponding wheel 13 in a straight-line driving state. Specifically, the front end of the second link 22 is provided with a V-shaped groove, and the locking mechanism 3 includes a mounting base 34. Figure 7 The mounting base shown in the image has its cross-sectional structure, a locking block 31, and an electromagnetic cylinder 35. The mounting base 34 is fixedly mounted on the lower swing arm 12. The front end of the locking block 31 has a V-shaped protrusion that can be embedded in the V-shaped groove of the second connecting rod 22. The rear end of the locking block 31 has two straight rods 32, which are fixedly mounted on the mounting base 34. A compression spring 33 is arranged on the straight rod 32, which forces the locking block 32 to fit against the V-shaped groove of the second connecting rod 22 and make them fit tightly. The electromagnetic cylinder 35 is arranged in the middle of the two straight rods 32 and is installed inside the mounting base 34. The actuator of the electromagnetic cylinder 35 is connected to the rear end of the straight rod 32 to force the straight rod 32 and the locking block 31 to move away from the V-shaped groove and separate the locking block 31 from the V-shaped groove. The electromagnetic cylinder 35 is connected to the controller.

[0056] In terms of electrical connection, current new energy vehicles are controlled by an on-board host, i.e., a vehicle control host, through driver operation or intelligent driving operation. In this solution, the vehicle control host collects data such as vehicle operating conditions through multiple components and performs corresponding operations. The vehicle control host is connected to the servo cylinder 23, the electromagnetic cylinder 35, and the rotation angle sensor through a controller. The servo cylinder 23 can be a drive structure with a worm gear to achieve a self-locking function. The servo cylinder 23 matches the deflection angle of the corresponding rear wheel according to the initially set stroke relationship. The rotation angle sensor can be arranged at the second ball joint. Through a high-precision combined Hall sensor, the current rotation angle of the second link can be accurately obtained, thereby achieving precise angle control and angle holding. The electromagnetic cylinder 35 is in the closed state in most cases. At this time, the locking mechanism 3 performs a locking operation on the second link 22. Since the V-shaped groove has a large-angle opening, the actual stroke of the locking block 31 can achieve its function in about 5 mm, so its operation is fast and accurate. Under the control of the vehicle control host's working logic, just before the servo cylinder 23 drives the second link 22 to rotate, the electromagnetic cylinder 35 can separate the locking block 31 from the second link 22. At the same time, when the locking operation is performed, it ensures that the second link 22 is aligned with the locking block 31 (i.e., the corresponding wheel is in a straight-line running state), thereby realizing the coordinated operation of the entire steering component 2.

[0057] A suspension system comprising the aforementioned independent rear-wheel steering configuration.

[0058] A new energy vehicle, including the aforementioned suspension.

[0059] This solution also includes a four-wheel steering control method, applied to the aforementioned independent rear-wheel steering structure, including:

[0060] The control host obtains the current vehicle speed value V and the front wheel steering angle A through the vehicle's functional components;

[0061] If the driving speed value V is greater than the first set value V1, and the front wheel steering angle value A is greater than the first set value A1, the controller will deflect the rear wheels in the same direction as the front wheel steering angle, and the deflection angle of the rear wheel on the outside of the turn will be greater than the deflection angle of the rear vehicle on the inside of the turn.

[0062] When the driving speed value V is less than the first set value V1, or the front wheel steering angle value A is less than the first set value A1;

[0063] The controller adjusts the left and right rear wheels to a straight-line running state and locks the left and right rear wheels.

[0064] refer to Figure 8 Figure 9Specifically, in this scenario, the vehicle is traveling at a relatively high speed, and rear-wheel steering is used to improve its lane-changing flexibility. The first setting value V1 can be 70 kilometers per hour, and the first setting value A1 can be ±8°. It should be noted that the first setting value V1 and the first setting value A1 can be a pair of combined values. In the triggering conditions, the higher the speed, the smaller the steering angle can be. As for rear-wheel deflection, the higher the speed, the smaller the deflection angle of the rear wheels should be.

[0065] In this method, by moving the rear wheel that is on the outside of the turn ( Figure 9 The right rear wheel's deflection angle is slightly greater than that of the rear wheel located on the inside of the turn. Figure 9 The deflection angle of the left rear wheel (middle rear wheel) generates a certain internal constraint force through the difference in deflection angle between the two rear wheels, thereby improving the stability of the vehicle and preventing oversteering. Secondly, the right rear wheel generates a certain internal resistance, thereby preventing the rear of the vehicle from sliding outwards, thus improving the stability and agility of the vehicle.

[0066] If the driving speed value V is less than the second set value V2, and the front wheel steering angle value A is greater than the second set value A2, the controller will deflect the rear wheels in the opposite direction to the front wheel steering angle, and the deflection angle of the rear wheel on the outside of the turn will be greater than the deflection angle of the rear vehicle on the inside of the turn.

[0067] refer to Figure 10 Specifically, in this scenario, the vehicle is traveling at a relatively slow speed, and rear-wheel steering is used to reduce the turning radius and improve the agility of turning or cornering. The second setting value V2 can be 30 km / h, and the second setting value A2 can be ±15°. Simply put, in situations where the vehicle speed is slow and the turning direction is large, the rear wheels (located on the outside of the turn) are used to reduce the turning radius and improve the agility of turning or cornering. Figure 10 The deflection angle of the right rear wheel is greater than that of the rear wheel located on the inside of the turn. Figure 10 The deflection angle of the left rear wheel (the middle and left rear wheels) is adjusted, thus creating a certain internal resistance through the left rear wheel, preventing the rear of the vehicle from sliding outwards and improving the stability and agility of the vehicle when turning.

[0068] If the driving speed value V is negative and the front wheel steering angle value A is greater than the second set value A2, the controller will deflect the rear wheels in the opposite direction to the front wheel steering angle, and the deflection angle of the rear wheel on the outside of the turn will be greater than the deflection angle of the rear vehicle on the inside of the turn.

[0069] Specifically, in this scenario, the vehicle is reversing at a relatively slow speed, similar to the previous slow cornering scenario. During reversing or parking, the vehicle is moving slowly and turning sharply. By increasing the deflection angle of the rear wheels on the outside of the turn compared to the rear wheels on the inside, a certain amount of internal resistance is created, preventing the rear of the vehicle from sliding outwards. This improves the stability and maneuverability of the vehicle during reversing.

[0070] A vehicle stability control method, applied to the aforementioned four-wheel steering suspension system, includes:

[0071] The control host obtains the current vehicle speed value V and the front wheel steering angle A through the vehicle's functional components;

[0072] The control unit senses the current rotational speed of the four tires through the ABS sensors on the wheels;

[0073] When the rotational speed of the left or right front wheel is significantly lower than that of the other three wheels, and the driving speed value V is greater than the third set value V3, and the front wheel steering angle value A is greater than the third set value A3, the controller will deflect the rear wheels in the same direction as the front wheel steering angle, and the deflection angle of the rear wheel on the outside of the turn will be greater than the deflection angle of the rear vehicle on the inside of the turn.

[0074] When the rotational speed of the left or right rear wheel is significantly lower than that of the other three wheels, and the driving speed value V is greater than the third set value V3, the controller will deflect the normal rear wheel in the same direction as the front wheel and perform a straight-line locking operation on the abnormal rear wheel.

[0075] When the rotational speed of the left or right rear wheel is significantly lower than that of the other three wheels, and the driving speed value V is greater than the third set value V3, and the front wheel steering angle value A is greater than the third set value A3, the controller will deflect the normal rear wheel in the same direction as the front wheel steering angle.

[0076] Specifically, in this scenario, if a tire blows out while the vehicle is traveling at high speed, the vehicle will veer off course due to the pulling effect of the blown tire, and the driver will steer in the opposite direction to correct the direction.

[0077] Through extensive data analysis, the inventors found that due to a lack of relevant experience, when a tire blows out, especially a front tire, the vehicle veers off course, and most drivers will steer in the opposite direction. This can lead to skidding, collisions, or rollovers. This method addresses this situation to improve vehicle stability.

[0078] refer to Figure 11 When the right front wheel ( Figure 11 A tire blowout occurs (shown in red in the middle). The first setting V3 can be 80 km / h, and the third setting A3 can be ±10°. This is achieved by controlling the rear wheel (located on the outside of the turn)... Figure 11 The deflection angle of the right rear wheel is greater than that of the rear wheel located on the inside of the turn. Figure 11 The deflection angle of the left rear wheel (the middle rear wheel) generates a certain internal constraint force through the difference in deflection angle between the two rear wheels, thereby improving the stability of the vehicle and preventing oversteering. Secondly, the left rear wheel generates a certain internal resistance, thereby preventing the rear of the vehicle from sliding outward or even overturning, thus improving the stability of the vehicle when a tire blows out.

[0079] refer to Figure 12 When the left rear wheel ( Figure 12 A tire blowout occurs (shown in red in the middle). The first setting V3 can be 80 km / h, and the third setting A can be ±10°. This is achieved by controlling the rear wheel (located on the outside of the turn)... Figure 12 The right rear wheel (the normal wheel) is set to deflect in the same direction as the front wheels, and the abnormal rear wheel... Figure 12 The left rear wheel is locked in a straight line to prevent oversteering and thus prevent the rear of the vehicle from skidding outwards or even overturning, thereby improving the vehicle's stability in the event of a tire blowout.

[0080] Thus, this solution provides differentiated rear-wheel steering control methods for multiple scenarios to improve vehicle stability, controllability, and flexibility. It is understandable that the application scenarios of this solution are widely applicable and cannot be listed one by one. However, implementing differentiated steering control of the rear wheels through the vehicle control host will certainly be more widely used and provide a more stable and reliable experience for drivers or passengers.

[0081] In summary, this independent rear-wheel steering structure, applied to new energy vehicles, allows for steering control of all four wheels, especially the rear wheels, through electronic control and the vehicle's main unit. By coordinating the steering control of the front and rear wheels, it enables high-speed rapid transit and low-speed cornering with a small turning radius. This solution employs an independent rear-wheel component structure, meaning the left and right rear wheels use completely independent steering components, which are entirely located at the lower control arm or lower linkage of the rear wheels. A lightweight structure is also used to reduce unsprung mass. Compared to traditional integrated steering systems, this rear-wheel steering system does not encroach on the rear chassis space and allows for precise angle control of the left and right rear wheels, enabling real-time rear-wheel function in multiple scenarios and significantly improving the vehicle's driving functionality and stability.

[0082] The steering component in this solution is mounted on the lower control arm or lower link, eliminating the need for extensive redesign of the existing vehicle structure. It is implemented through a drive mechanism consisting of a first link, a second link, and a high-precision servo cylinder. The first and second links form a triangular force-bearing structure, as do the second link and the drive mechanism, significantly improving structural stability. The rotational force of the wheels is transferred to the subframe through the structure of the first and second links, reducing the force distribution to the servo cylinder drive mechanism. The large stroke with a small angle configuration improves the accuracy of wheel rotation and the controllability of the servo cylinder drive mechanism. At the same time, locating the entire steering component on the lower control arm or lower link reduces the impact of the vehicle's up-and-down shock-absorbing movement on the steering system, resulting in less interference and more stable operation.

[0083] This solution has a locking mechanism at the end of the second link of the steering component, which can lock the vehicle when the rear wheels are in a straight line during normal driving. This greatly improves the stability of the vehicle and reduces the need for the servo cylinder drive mechanism that controls the steering of the rear wheels to be in standby mode. This reduces its workload and improves its stability and service life.

[0084] This solution is a four-wheel steering control method that achieves multi-scenario application functions by independently controlling the angle of the rear wheels. In particular, by implementing different rear wheel deflection angles for the two rear wheels, it can improve the vehicle's tracking performance and reduce the occurrence of sideslip, oversteer, or understeer when the vehicle is traveling at relatively high speeds. When the vehicle is turning at low speeds or reversing into a parking space, it can improve the vehicle's driving stability, reduce the turning radius, and improve the convenience of turning and entering and exiting parking spaces.

[0085] This solution is a vehicle stability control method, mainly to deal with situations such as wheel abnormalities (e.g., tire blowout) at high speeds. In such situations, the driver is prone to oversteering in the opposite direction due to the pull on one side, which can lead to loss of control or rollover. This solution reduces oversteering and rollover by steering the rear wheels in the same direction as the front wheels, thereby greatly improving stability and controllability in extreme conditions.

[0086] This solution enables differentiated and functional operation in multiple vehicle driving scenarios by allowing completely independent control and adjustment of the rear wheels. It has great potential for widespread adoption and will play a positive role in my country's new energy vehicle technology and application.

Claims

1. A self-contained rear wheel steering arrangement characterised in that: It includes a lower control arm or lower connecting rod, and a steering component arranged at the lower control arm or lower connecting rod. The steering component is arranged at the lower control arm or lower connecting rod of the left rear wheel and the right rear wheel. One end is hinged to the steering seat through a ball joint component, and the other end is hinged to the lower control arm or lower connecting rod. A rotation drive mechanism is hinged at the lower control arm or lower connecting rod. The rotation drive mechanism is connected to the controller and drives the steering seat to rotate accordingly through the connecting rod component. The steering component includes a first link and a second link. The first link is connected to the steering arm of the steering seat through a first ball joint. The other end of the first link is hinged to the second link. One end of the second link is connected to the lower control arm or the lower link through a second ball joint. A rotation drive mechanism is arranged on the second link. The first ball joint is located at the lower rear side of the wheel center point when the vehicle is moving forward, and the second ball joint is located near the lower control arm or lower linkage and the frame mounting structure. The second link extends outward at the hinge point with the first link and is provided with a hinge structure. A third ball joint is provided at the lower swing arm or the lower link. A drive mechanism is provided between the third ball joint and the hinge structure. The drive mechanism is used to drive the second link and make it rotate around the second ball joint. This causes the steering component to form a triangular force-bearing structure with the first link and the second link as the framework, and a triangular force-bearing structure with the second link and the drive mechanism as the framework.

2. The independent rear wheel steering structure according to claim 1, characterized by: The front end of the second link is provided with a locking mechanism. The locking mechanism is used to restrict the rotation of the second link and keep the corresponding wheel in a straight-line driving state. The front end of the second link has a V-shaped groove. The locking mechanism includes a locking block and a locking block driving mechanism. The front end of the locking block is provided with a V-shaped protrusion. The front end of the V-shaped protrusion can be embedded in the V-shaped groove.

3. A suspension, characterized by: Includes the independent rear-wheel steering structure as described in any one of claims 1 to 2.

4. A new energy vehicle, characterized in that: Including a suspension as described in claim 3.

5. A four-wheel steering control method applied to the independent rear wheel steering structure according to any one of claims 1 to 2, characterized by: include: The control host obtains the current vehicle speed value V and the front wheel steering angle A through the vehicle's functional components; If the driving speed value V is greater than the first set value V1, and the front wheel steering angle value A is greater than the first set value A1, the controller will deflect the rear wheels in the same direction as the front wheel steering angle, and the deflection angle of the rear wheel on the outside of the turn will be greater than the deflection angle of the rear wheel on the inside of the turn.

6. The four-wheel steering control method according to claim 5, characterized by: If the driving speed value V is less than the second set value V2, and the front wheel steering angle value A is greater than the second set value A2, the controller will deflect the rear wheels in the opposite direction to the front wheel steering angle, and the deflection angle of the rear wheel on the outside of the turn will be greater than the deflection angle of the rear vehicle on the inside of the turn. If the driving speed value V is negative and the front wheel steering angle value A is greater than the second set value A2, the controller will deflect the rear wheels in the opposite direction to the front wheel steering angle, and the deflection angle of the rear wheel on the outside of the turn will be greater than the deflection angle of the rear vehicle on the inside of the turn.

7. A control method for vehicle stable running, applied to the independent rear wheel steering structure according to any one of claims 1 to 2, characterized by: include: The control host obtains the current vehicle speed value V and the front wheel steering angle A through the vehicle's functional components; The control unit senses the current rotational speed of the four tires through the ABS sensors on the wheels; When the rotational speed of the left front wheel or the right front wheel is significantly smaller than the other three wheels, and the running speed value V is greater than the third set value V3, and the front wheel steering angle value A is greater than the third set value A3, the controller implements the deflection of the rear wheels in the same direction as the front wheel steering angle direction; When the rotational speed of the left rear wheel or the right rear wheel is significantly smaller than the other three wheels, and the running speed value V is greater than the third set value V3, and the front wheel steering angle value A is greater than the third set value A3, the controller implements the deflection of the normal rear wheels in the same direction as the front wheel steering angle direction.

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