Independent rear wheel steering structure, suspension, new energy vehicle and control method

Abstract

The invention discloses an independent rear wheel steering structure, a suspension, a new energy vehicle and a control method, and belongs to the technical field of new energy vehicle chassis. The independent rear wheel steering structure comprises a lower swing arm or a lower connecting rod and an upper steering component arranged on the lower swing arm or the lower connecting rod; the steering parts are arranged at lower swing arms or lower connecting rods of the left rear wheel and the right rear wheel, one ends of the steering parts are hinged to the steering bases through ball head parts, the other ends of the steering parts are hinged to the lower swing arms or the lower connecting rods, and rotation driving mechanisms are arranged at the lower swing arms or the lower connecting rods in a hinged mode and connected with the controller. And the steering seat is driven to correspondingly rotate through the connecting rod component.

Description

Technical Field

[0001] The present invention relates to the technical field of chassis of new energy vehicles, and in particular to an independent rear wheel steering structure, a suspension, a new energy vehicle and a control method. Background Art

[0002] The rear-wheel steering of a vehicle means that in addition to the front-wheel steering, the rear wheel angle can be adjusted to assist steering. This method can make the rear wheels deflect in the same direction as the front wheels at low speeds and deflect in the opposite direction at high speeds. It can improve the flexibility of the vehicle. When parking or turning at low speeds, the rear wheels deflect in the same direction as the front wheels to make the vehicle body more flexible and reduce the turning radius; it can also enhance stability. When driving at high speeds, the rear wheel deflection in the opposite direction helps improve the vehicle's straight-line stability and response speed when changing lanes.

[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, the so-called four-wheel steering suspension system, which combines the advantages of front-wheel steering and rear-wheel steering, and automatically adjusts the angles of the front and rear wheels under different speed conditions to achieve the best control effect and safety. And play the corresponding advantages in multiple usage scenarios.

[0004] However, the existing rear-wheel steering structure usually uses the integrated steering seat structure of the front-wheel steering. Due to the complex structure of the rear wheel and rear axle, multiple components need to be arranged, such as the four-wheel drive system, some batteries or fuel tanks, or when arranging the motor and drive structure, it is easy to have unreasonable structural configuration or occupy the interior space of the car. At the same time, the operation of the rear wheels, especially when the vehicle is running at high speed, requires extremely high stability of the rear wheels. A slight deviation will cause the vehicle to have an abnormal posture phenomenon that exceeds the expected control difficulty. Especially for special situations such as slippery roads, abnormal potholes or tire blowouts, the traditional rear-wheel steering structure still has many shortcomings, so more attempts and research are needed for the four-wheel steering of new energy vehicles. Summary of the invention

[0005] The purpose of the present invention is to provide an independent rear-wheel steering structure, suspension, new energy vehicle and control method, which can improve the vehicle's rear-wheel steering structure, provide vehicle controllability, and achieve targeted control in multiple usage scenarios.

[0006] In order to achieve the above object, the technical solution of the present invention is as follows: An independent rear wheel steering structure includes 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 the left rear wheel and the right rear wheel, one end of which is hinged to the steering seat through a ball head component, and the other end is hinged to the lower swing arm or the lower connecting rod. A rotation drive mechanism is hingedly arranged at the lower swing arm or the lower connecting rod, and the rotation drive mechanism is connected to a controller, and drives the steering seat to rotate accordingly through the connecting rod component.

[0007] Furthermore, the steering component includes a first connecting rod and a second connecting rod, the first connecting rod is connected to the steering arm of the steering seat through a first ball head, the other end of the first connecting rod is hinged to the second connecting rod, the other end of the second connecting rod is connected to the lower swing arm or the lower connecting rod through a second ball head, and a rotation drive mechanism is arranged on the second connecting rod.

[0008] Furthermore, the first ball head is arranged at a lower rear side position of the wheel center point when the vehicle is moving forward, and the second ball head is arranged at a position close to the lower control arm or the lower connecting rod and the frame mounting structure.

[0009] Furthermore, the second connecting rod extends outward at the hinge with the first connecting rod and is arranged with a hinge structure, and a third ball head is arranged at the lower swing arm or the lower connecting rod, and a driving mechanism is arranged between the third ball head and the hinge structure. The driving mechanism is used to drive the second connecting rod and make it rotate around the second ball head, so that the steering component constructs a triangular force-bearing structure with the first connecting rod and the second connecting rod as the frame, and a triangular force-bearing structure with the second connecting rod and the driving mechanism as the frame.

[0010] Furthermore, a locking mechanism is arranged at the front end of the second connecting rod, which is used to limit the rotation of the second connecting rod and make the corresponding wheel in a straight driving state. The front end of the second connecting rod has a V-shaped groove, and the locking mechanism includes a card block and a card block driving mechanism. The front end of the card block is provided with a V-shaped protrusion, and the front end of the V-shaped protrusion can be embedded in the V-shaped groove.

[0011] A suspension comprises the above-mentioned independent rear wheel steering structure.

[0012] A new energy vehicle comprises the above-mentioned suspension.

[0013] A four-wheel steering control method, applied to the above-mentioned independent rear wheel steering structure, comprises: The control host obtains the current vehicle speed value V and the front wheel steering angle A through the vehicle 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 implements deflection of the rear wheels in the same direction as the front wheel steering angle, and the deflection angle of the rear wheels on the outside of the turn is greater than the deflection angle of the rear wheels on the inside of the turn.

[0014] Further, 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 implements the deflection of the rear wheels in the opposite direction to the front wheel steering angle, and the deflection angle of the rear wheels on the outside of the turn is greater than the deflection angle of the rear vehicle on the inside of the turn; If the driving speed value V is a negative value and the front wheel steering angle value A is greater than the second set value A2, the controller implements deflection of the rear wheels in the opposite direction of the front wheel steering angle, and the deflection angle of the rear wheels on the outside of the turn is greater than the deflection angle of the rear vehicle on the inside of the turn.

[0015] A method for controlling stable driving of a vehicle, applied to the above-mentioned independent rear wheel steering structure, comprises: The control host obtains the current vehicle speed value V and the front wheel steering angle A through the vehicle functional components; The control host senses the current rotation speed of the four tires through the ABS sensors of the wheels; When the rotation speed of the left front wheel or the 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 implements the deflection of the rear wheel in the same direction as the front wheel steering angle; When the rotation speed of the left rear wheel or the 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 implements deflection of the normal rear wheels in the same direction as the front wheel steering angle.

[0016] Compared with the existing technology, this solution has the following advantages: The independent rear-wheel steering structure of this scheme is applied to new energy vehicles. Through the electronic control and the vehicle host, the steering control of the four wheels, especially the rear wheels, can be implemented. Through the coordination of the steering control of the front and rear wheels, high-speed expressways and low-speed and low-turning radius cornering can be achieved. This scheme adopts an independent rear wheel assembly structure, that is, the left and right rear wheels use completely independent steering components, and the steering components are completely arranged at the lower arm or lower connecting rod of the rear wheel. At the same time, a lightweight structure is adopted to reduce the unsprung mass. Compared with the rear-wheel steering system with a traditional integrated steering gear structure, there is no need to occupy the rear wheel chassis space, and the left and right rear wheels can be individually and accurately controlled in angle, so as to realize the rear wheel function in real time in multiple scenes, greatly improving the functionality and stability of the vehicle's driving; The steering component of this solution is constructed at the lower arm or the lower connecting rod, and there is no need to re-involve the structure of the existing vehicle on a large scale. It is implemented through the first connecting rod, the second connecting rod and the driving mechanism of the high-precision servo cylinder, and the triangular force-bearing structure with the first connecting rod and the second connecting rod as the frame, and the triangular force-bearing structure with the second connecting rod and the driving mechanism as the frame, which greatly improves the structural stability, and transmits the rotating force-bearing body of the wheel to the subframe through the structure of the first connecting rod and the second connecting rod, reducing the distribution of the force of the servo cylinder driving mechanism, and the configuration of large stroke for small angle improves the accuracy of wheel rotation and the controllability of the servo cylinder driving mechanism. At the same time, the entire steering component is arranged at the lower arm or the lower connecting rod, which can reduce the impact of the up and down shock-absorbing movement of the vehicle's running wheels on the steering system, making it less interfered with work and more stable. The present invention arranges a locking mechanism at the end of the second connecting rod of the steering component, which can be locked when the rear wheels of the vehicle are in a straight line during normal driving, thereby greatly improving the stability of the vehicle operation and reducing the standby state of the servo cylinder driving mechanism for controlling the rear wheel steering, thereby reducing its working intensity and improving its use stability and service life; This scheme is a four-wheel steering control method, which realizes application functions in multiple scenarios by independently controlling the angles of the rear wheels. In particular, by implementing different rear wheel deflection angles on the two rear wheels, the vehicle's tracking performance can be improved in the scenario of relatively high-speed driving, and the occurrence of side slip, oversteering or understeering can be reduced; when the vehicle is turning at a low speed or reversing into a garage, the vehicle's driving stability can be improved, the turning radius can be reduced, and the convenience of turning and entering and exiting the garage can be improved; This solution is a control method for stable driving of a vehicle, which is mainly used to deal with situations such as wheel abnormalities (such as tire blowout) at high speed. In this situation, the driver of the vehicle is prone to steer in the opposite direction due to unilateral pulling, which may cause the vehicle to lose control or roll over. This solution can reduce 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. This solution can perform differentiated and functional operations in multiple vehicle driving scenarios by performing completely independent control and adjustment of the rear wheels. It has excellent promotion significance and will play a positive role in my country's new energy vehicle technology and applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic structural diagram of a vehicle of a preferred embodiment.

[0018] Figure 2 It is a schematic diagram of the rear wheel assembly structure of a vehicle.

[0019] Figure 3This is a schematic diagram of the steering component layout for the right rear wheel.

[0020] Figure 4 It is a structural schematic diagram of the steering component.

[0021] Figure 5 A top view of the steering component.

[0022] Figure 6 This is a schematic diagram of the structure in rotation state.

[0023] Figure 7 Schematic diagram of the locking mechanism structure.

[0024] Figure 8 This is a schematic diagram of the four-wheel structure of the vehicle in a straight line state.

[0025] Fig. 9 This is a schematic diagram of the four-wheel structure in the first working state.

[0026] Fig.10 This is a schematic diagram of the four-wheel structure in the second working state.

[0027] Fig.11 This is a schematic diagram of the four-wheel structure in the third working state.

[0028] Fig.12 This is a schematic diagram of the four-wheel structure in the fourth working state. DETAILED DESCRIPTION

[0029] refer to Figures 1 to 5 , a new energy vehicle comprises: 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, and the steering gear 11 controls the connection and controls the rotation direction and angle of the left front wheel and the right front wheel; The rear wheel assembly includes a left rear wheel and a right rear wheel, and a suspension structure connecting the two wheels. A steering component 2 is arranged in the suspension structure. The steering component 2 is used to independently control the rotation direction and angle of the left rear wheel and the right rear wheel; The controller controls the steering component to independently control the rotation direction and angle of the left rear wheel and the right rear wheel according to the command of the vehicle control host; The rotation angle sensor is arranged at the steering component 2, and is used to obtain the current rotation angle value of the left rear wheel or the right rear wheel in real time, and feed the rotation angle value back to the vehicle control host; Specifically, the four wheels of the vehicle are mounted on the subframe 10 through a suspension structure, the subframe 10 is connected to the vehicle body 1, and forms the entire vehicle body structure, wherein the left front wheel and the right front wheel receive control from the driver through a steering gear 11, or receive control from the vehicle control host in the case of intelligent driving, to achieve synchronous rotation control of the left front wheel and the right front wheel, thereby controlling the driving direction of the vehicle; In order to realize the steering control of the rear wheels, the left rear wheel and the right rear wheel are connected to the subframe 10 through the lower control arm 12, a ball head is arranged at the front end of the lower control arm 12, the ball head is connected to the steering seat 14, and structures such as springs and shock absorbers are arranged above the steering seat 14 to realize the up and down shock-absorbing movement of the wheel 13 and realize the function of rotation centered on the ball head.

[0030] It should be noted that the wheel suspension structure has multiple mainstream structures, such as McPherson suspension, double wishbone suspension or multi-link suspension, etc. Generally speaking, if the steering control of the wheel is to be implemented, a rotatable shaft mechanism and a driving mechanism that drives the vehicle's mounting part (steering seat) to rotate with the shaft are required in the vertical direction. This solution is explained with a lower swing arm structure, but it does not mean that this solution is only limited to use in this lower swing arm structure. Technical personnel in this field can also apply this solution to various vehicle suspension structures.

[0031] The independent rear wheel steering structure includes a lower swing arm arranged at the left rear wheel and the right rear wheel, and 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 through a first ball head, and 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 swing arm 2 through a second ball head. Among them, the first ball head is arranged at the rear lower side position of the center point of the wheel 13 in the forward driving direction of the vehicle. By arranging the first ball head at the rear of the forward movement, the steering component 2 can form a traction and drag structure, which can improve the driving stability and reduce the impact on the steering component under various circumstances; the second ball head is arranged at a position close to the lower swing arm 12 and the mounting structure of the subframe 10. Such an arrangement can make full use of the space of the lower swing arm 12, extend the length of the first link 21 and the second link 22, thereby reducing the impact of the wheel's up and down shock absorption movement, and make the force of the second ball head transmitted to the subframe in the shortest possible way.

[0032] The second connecting rod 22 extends outward at the hinge with the first connecting rod 21 and is arranged with a hinge structure. A third ball head is arranged at the lower swing arm 12. A high-precision servo cylinder 23 is arranged between the third ball head and the hinge structure. The servo cylinder 23 is connected to the controller and is used to drive the second connecting rod 22 and make it rotate around the second ball head. 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 accurate and reliable with a large motion stroke.

[0033] Therefore, at the lower control arm 12, the steering component 2 is constructed into a triangular force-bearing structure with the first connecting rod 21 and the second connecting rod 22 as the frame, and a triangular force-bearing structure with the second connecting rod 22 and the servo cylinder 23 as the frame. Through the two triangular force-bearing structures that share the second connecting rod 22, the force of the entire steering component 2 can be made more balanced, 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 in the corresponding space frame of the lower control arm and will not invade other vehicle body spaces.

[0034] refer to Figure 6 In this embodiment, the maximum steering angle of the rear wheel is designed to be ±10° as a standard (where red represents a +10° deflection of the wheel, and blue represents a -10° deflection) (it should be noted that, after appropriate structural optimization, its maximum rotation angle can be greater than ±10° as a design standard), and the corresponding rotation angle of the second connecting rod 22 is 39.16°, so the rotation angle at the second connecting rod 22 is magnified by 1.958 times; the rotation stroke of the first ball head is 22.62 units, and the corresponding stroke of the front end of the servo cylinder 23 is 46.92 units, so the stroke of the servo cylinder 23 is correspondingly magnified by 2.07 times; at the same time, through these two triangular force-bearing structures, the impact force of the wheel is mainly transmitted by the second ball head to the lower arm 12 and the subframe 10, and the servo cylinder 23 is allocated 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.

[0035] refer to Figure 7 In some embodiments, a locking mechanism 3 is arranged at the front end of the second connecting rod 22, and the locking mechanism 3 is used to limit the rotation of the second connecting rod 22 and keep the corresponding wheel 13 in a straight-line driving state. Specifically, a V-shaped groove is arranged at the front end of the second connecting rod 22, and the locking mechanism 3 includes a mounting seat 34 ( Figure 7 The mounting seat shown in the figure is its cross-sectional structure), a block 31 and an electromagnetic cylinder 35, the mounting seat 34 is fixedly mounted on the lower swing arm 12, a V-shaped protrusion is provided at the front end of the block 31, and the front end of the V-shaped protrusion can be embedded in the V-shaped groove arranged in the second connecting rod 22, and two straight rods 32 are arranged at the rear end of the block 31, and the straight rod 32 is restricted to be installed at the mounting seat 34, and a compression spring 33 is arranged on the straight rod 32, and the compression spring 33 forces the block 32 to fit into the V-shaped groove of the second connecting rod 22, and makes the two fit tightly, and an electromagnetic cylinder 35 is arranged in the middle of the two straight rods 32, and the electromagnetic cylinder 35 is installed inside the mounting seat 34, and the actuator of the electromagnetic cylinder 35 is connected to the rear end of the straight rod 32, and is used to force the straight rod 32 and the block 31 to move in a direction away from the V-shaped groove, and realize that the block 31 and the V-shaped groove are separated, and the electromagnetic cylinder 35 is connected to the controller.

[0036] In terms of electrical connection, the current new energy vehicles are controlled by the on-board host, that is, the vehicle control host, through the driver's operation or intelligent driving operation. In this solution, the vehicle control host collects data including the working conditions of the vehicle through multiple components and implements corresponding operations. The vehicle control host is connected to the servo cylinder 23, the electromagnetic cylinder 35 and the rotation angle sensor through the controller, wherein 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 stroke relationship set initially; the rotation angle sensor can be arranged at the second ball head, and the current rotation angle of the second connecting rod can be accurately obtained through a high-precision combined Hall sensor, thereby achieving its precise angle control and angle maintenance; the electromagnetic cylinder 35 is in a closed state in most cases. At this time, the locking mechanism 3 implements the locking operation of the second connecting rod 22. Since the V-shaped groove has a large-angle opening, the actual stroke of the block 31 can achieve its function in about 5 mm, so its operation is fast and accurate. Under the working logic control of the vehicle control host, the electromagnetic cylinder 35 can separate the block 31 from the second connecting rod 22 at a moment before the servo cylinder 23 drives the second connecting rod 22 to rotate. At the same time, when the locking operation is implemented, it ensures that the second connecting rod 22 is aligned with the block 31 (that is, the corresponding wheel is in a straight line running state), thereby achieving coordinated cooperation of the entire steering component 2.

[0037] A suspension comprises the above-mentioned independent rear wheel steering structure.

[0038] A new energy vehicle comprises the above-mentioned suspension.

[0039] The present invention also includes a four-wheel steering control method, which is applied to the above-mentioned independent rear wheel steering structure, including: The control host obtains the current vehicle speed value V and the front wheel steering angle A through the vehicle 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 implements the deflection of the rear wheels in the same direction as the front wheel steering angle, and the deflection angle of the rear wheels on the outside of the turn is greater than the deflection angle of the rear vehicle on the inside of the turn; 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; The controller adjusts the left rear wheel and the right rear wheel to a straight-line running state, and performs locking operations on the left rear wheel and the right rear wheel.

[0040] refer to Figure 8 Fig. 9Specifically, in this scenario, the vehicle is traveling at a relatively high speed, and the rear wheel steering is used to improve its flexibility in changing lanes. The first setting value V1 may be 70 kilometers per hour, and the first setting value A1 may be ±8°. It should be noted that the first setting value V1 and the first setting value A1 may be a pair of combination values. In the triggering condition, the greater the speed, the smaller the steering angle may be. As for the rear wheel deflection, the greater the speed, the smaller the deflection angle of the rear wheel should be. In this method, the rear wheel on the outside of the turn ( Fig. 9 The deflection angle of the rear wheel on the inside of the turn ( Fig. 9 Therefore, firstly, a certain internal restraint force is generated through the deflection angle difference of the two rear wheels, thereby improving the stability of the vehicle and preventing oversteering; secondly, a certain internal resistance is achieved through the right rear wheel, thereby preventing the tail of the vehicle from sliding to the outside, thereby improving the stability and flexibility of the vehicle.

[0041] 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 implements deflection of the rear wheels in the opposite direction of the front wheel steering angle, and the deflection angle of the rear wheels on the outside of the turn is greater than the deflection angle of the rear vehicle on the inside of the turn.

[0042] refer to Fig.10 Specifically, in this scenario, the vehicle is traveling at a slower speed, and the rear wheel steering is used to reduce the turning radius and improve the flexibility of turning or cornering. The second setting value V2 can be 30 kilometers per hour, and the second setting value A2 can be ±15°. In short, the vehicle speed is slow and the turning direction is large; by turning the rear wheels on the outside of the turn ( Fig.10 The deflection angle of the rear wheel on the inside of the turn ( Fig.10 Therefore, a certain internal resistance is achieved through the left rear wheel, thereby preventing the tail of the vehicle from sliding outwards, thereby improving the stability and flexibility of the vehicle in turning.

[0043] If the driving speed value V is a negative value and the front wheel steering angle value A is greater than the second set value A2, the controller implements deflection of the rear wheels in the opposite direction of the front wheel steering angle, and the deflection angle of the rear wheels on the outside of the turn is greater than the deflection angle of the rear vehicle on the inside of the turn.

[0044] Specifically, in this scenario, the vehicle is reversing at a slower speed, which is similar to the previous slow cornering scenario. The vehicle is reversing or reversing into a garage at a slower speed and with a larger turn. By making the deflection angle of the rear wheels on the outside of the turn greater than the deflection angle of the rear wheels on the inside of the turn, a certain internal resistance is achieved, thereby preventing the rear end of the vehicle from sliding outward, thereby improving the stability and flexibility of the vehicle in reversing operations.

[0045] A method for controlling stable driving of a vehicle, applied to the above-mentioned four-wheel steering suspension system, comprises: The control host obtains the current vehicle speed value V and the front wheel steering angle A through the vehicle functional components; The control host senses the current rotation speed of the four tires through the ABS sensors of the wheels; When the rotation speed of the left front wheel or the 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 implements deflection of the rear wheels in the same direction as the front wheel steering angle, and the deflection angle of the rear wheels on the outside of the turn is greater than the deflection angle of the rear vehicle on the inside of the turn.

[0046] When the rotation speed of the left rear wheel or the 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 deflects the normal rear wheels in the same direction as the front wheels, and performs a straight-line locking operation on the abnormal rear wheels.

[0047] When the rotation speed of the left rear wheel or the 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 implements deflection of the normal rear wheels in the same direction as the front wheel steering angle.

[0048] Specifically, in this scenario, when a vehicle is traveling at high speed and a tire blows out, the vehicle deviates due to the pulling of the tire blown out wheel, and the driver turns the steering wheel in the opposite direction to correct the direction. After a lot of data analysis, the inventor found that due to the lack of corresponding experience, when a tire bursts, especially a front tire bursts, because the vehicle deflects, most drivers will steer in the opposite direction, which will eventually cause the vehicle to skid, collide or roll over in the direction of the reverse steering. The present method is used to deal with this situation to improve the stability of the vehicle. refer to Fig.11 , when the right front wheel ( Fig.11 If a tire bursts, the first setting value V3 can be 80 kilometers per hour, and the third setting value A3 can be ±10°. By turning the rear wheel ( Fig.11 The deflection angle of the rear wheel on the inside of the turn ( Fig.11 Therefore, firstly, a certain internal restraint force is generated through the deflection angle difference of the two rear wheels, thereby improving the stability of the vehicle and preventing oversteering. Secondly, a certain internal resistance is achieved through the left rear wheel, thereby preventing the tail of the vehicle from sliding to the outside or even rolling over, thereby improving the driving stability of the vehicle when the tire bursts.

[0049] refer to Fig.12 , when the left rear wheel ( Fig.12 If a tire bursts, the first setting value V3 can be 80 kilometers per hour, and the third setting value A can be ±10°. By turning the rear wheel ( Fig.12 The normal wheel (the right rear wheel in the middle) is set to deflect in the same direction as the front wheel, and the abnormal rear wheel, i.e. Fig.12 The left rear wheel is locked in a straight line to prevent oversteering, thereby preventing the rear end of the vehicle from sliding outward or even rolling over, thereby improving the driving stability of the vehicle when a tire bursts.

[0050] So far, this solution provides differentiated rear-wheel steering control methods for multiple scenarios to improve the stability, controllability and flexibility of the vehicle. It is understandable that the application scenarios of this solution have wide adaptability and cannot be illustrated one by one, but the differentiated steering control of the rear wheels implemented by the vehicle control host will definitely be more widely used and provide a more stable and reliable experience for the driver or passengers.

[0051] In summary, the independent rear-wheel steering structure of this scheme is applied to new energy vehicles. Through the electronic control and the vehicle host, the steering control of the four wheels, especially the rear wheels, can be implemented. Through the coordination of the steering control of the front and rear wheels, high-speed expressways and low-speed and low-turning radius cornering can be achieved. This scheme adopts an independent rear wheel assembly structure, that is, the left and right rear wheels use completely independent steering components, and the steering components are completely arranged at the lower arm or lower connecting rod of the rear wheel. At the same time, a lightweight structure is adopted to reduce the unsprung mass. Compared with the rear-wheel steering system with a traditional integrated steering gear structure, there is no need to occupy the rear wheel chassis space, and the left and right rear wheels can be individually and accurately controlled in angle, so as to realize the rear wheel function in real time in multiple scenes, which greatly improves the functionality and stability of the vehicle's driving. The steering component of this solution is constructed at the lower arm or the lower connecting rod, and there is no need to re-involve the structure of the existing vehicle on a large scale. It is implemented through the first connecting rod, the second connecting rod and the driving mechanism of the high-precision servo cylinder, and the triangular force-bearing structure with the first connecting rod and the second connecting rod as the frame, and the triangular force-bearing structure with the second connecting rod and the driving mechanism as the frame, which greatly improves the structural stability, and transmits the rotating force-bearing body of the wheel to the subframe through the structure of the first connecting rod and the second connecting rod, reducing the distribution of the force of the servo cylinder driving mechanism, and the configuration of large stroke for small angle improves the accuracy of wheel rotation and the controllability of the servo cylinder driving mechanism. At the same time, the entire steering component is arranged at the lower arm or the lower connecting rod, which can reduce the impact of the up and down shock-absorbing movement of the vehicle's running wheels on the steering system, making it less interfered with work and more stable. The present invention arranges a locking mechanism at the end of the second connecting rod of the steering component, which can be locked when the rear wheels of the vehicle are in a straight line during normal driving, thereby greatly improving the stability of the vehicle operation and reducing the standby state of the servo cylinder driving mechanism for controlling the rear wheel steering, thereby reducing its working intensity and improving its use stability and service life; This scheme is a four-wheel steering control method, which realizes application functions in multiple scenarios by independently controlling the angles of the rear wheels. In particular, by implementing different rear wheel deflection angles on the two rear wheels, the vehicle's tracking performance can be improved in the scenario of relatively high-speed driving, and the occurrence of side slip, oversteering or understeering can be reduced; when the vehicle is turning at a low speed or reversing into a garage, the vehicle's driving stability can be improved, the turning radius can be reduced, and the convenience of turning and entering and exiting the garage can be improved; This solution is a control method for stable driving of a vehicle, which is mainly used to deal with situations such as wheel abnormalities (such as tire blowout) at high speed. In this situation, the driver of the vehicle is prone to steer in the opposite direction due to unilateral pulling, which may cause the vehicle to lose control or roll over. This solution can reduce 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. This solution can perform differentiated and functional operations in multiple vehicle driving scenarios by performing completely independent control and adjustment of the rear wheels. It has excellent promotion significance and will play a positive role in my country's new energy vehicle technology and applications.

Claims

1. Independent rear wheel steering structure, characterized by: It includes a lower swing arm or a lower connecting rod, and a steering component arranged at 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 the left rear wheel and the right rear wheel, one end of which is hinged to the steering seat through a ball head component, and the other end is hinged to the lower swing arm or the lower connecting rod. A rotation drive mechanism is hingedly arranged at the lower swing arm or the lower connecting rod, and the rotation drive mechanism is connected to a controller, and drives the steering seat to rotate accordingly through the connecting rod component.

2. The independent rear wheel steering structure according to claim 1, characterized in that: The steering component includes a first connecting rod and a second connecting rod. The first connecting rod is connected to the steering arm of the steering seat through a first ball head. The other end of the first connecting rod is hinged to the second connecting rod. One end of the second connecting rod is connected to the lower swing arm or the lower connecting rod through a second ball head. A rotation drive mechanism is arranged on the second connecting rod.

3. The independent rear wheel steering structure according to claim 1, characterized in that: The first ball head is arranged at the lower rear side of the wheel center point when the vehicle is moving forward, and the second ball head is arranged at a position close to the lower control arm or the lower connecting rod and the frame mounting structure.

4. The independent rear wheel steering structure according to claim 1, characterized in that: The second connecting rod extends outward at the hinge with the first connecting rod and is arranged with a hinge structure. A third ball head is arranged at the lower swing arm or the lower connecting rod. A driving mechanism is arranged between the third ball head and the hinge structure. The driving mechanism is used to drive the second connecting rod and make it rotate around the second ball head, so that the steering component constructs a triangular force-bearing structure with the first connecting rod and the second connecting rod as the frame, and a triangular force-bearing structure with the second connecting rod and the driving mechanism as the frame.

5. The independent rear wheel steering structure according to claim 1, characterized in that: A locking mechanism is arranged at the front end of the second connecting rod, and the locking mechanism is used to limit the rotation of the second connecting rod and make the corresponding wheel in a straight driving state. The front end of the second connecting rod has a V-shaped groove, and the locking mechanism includes a card block and a card block driving mechanism. The front end of the card block is provided with a V-shaped protrusion, and the front end of the V-shaped protrusion can be embedded in the V-shaped groove.

6. A suspension, characterized in that: Including the above-mentioned independent rear wheel steering structure.

7. A new energy vehicle, characterized in that: Including a suspension as mentioned above.

8. A four-wheel steering control method, applied to the above-mentioned independent rear wheel steering structure, characterized in that: include: The control host obtains the current vehicle speed value V and the front wheel steering angle A through the vehicle 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 implements deflection of the rear wheels in the same direction as the front wheel steering angle, and the deflection angle of the rear wheels on the outside of the turn is greater than the deflection angle of the rear wheels on the inside of the turn.

9. A four-wheel steering control method according to claim 8, characterized in that: 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 implements the deflection of the rear wheels in the opposite direction to the front wheel steering angle, and the deflection angle of the rear wheels on the outside of the turn is greater than the deflection angle of the rear vehicle on the inside of the turn; If the driving speed value V is a negative value and the front wheel steering angle value A is greater than the second set value A2, the controller implements deflection of the rear wheels in the opposite direction of the front wheel steering angle, and the deflection angle of the rear wheels on the outside of the turn is greater than the deflection angle of the rear vehicle on the inside of the turn.

10. A method for controlling stable driving of a vehicle, applied to the above-mentioned independent rear wheel steering structure, characterized in that: include: The control host obtains the current vehicle speed value V and the front wheel steering angle A through the vehicle functional components; The control host senses the current rotation speed of the four tires through the ABS sensors of the wheels; When the rotation speed of the left front wheel or the 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 implements the deflection of the rear wheel in the same direction as the front wheel steering angle; When the rotation speed of the left rear wheel or the 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 implements deflection of the normal rear wheels in the same direction as the front wheel steering angle.

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