Rear wheel steering gear having locking function, and vehicle

Abstract

A rear wheel steering gear having a locking function, and a vehicle. A housing of the rear wheel steering gear is used for accommodating a rotary input member, a rotary output member, a plurality of pairs of rolling members, and a plurality of elastic components. The rotary input member is used for receiving drive of a steering motor and is used for transmission connection with the rotary output member, and the rotary output member is used for transmission connection with a tie rod of a rear wheel of the vehicle. The rotary input member comprises a plurality of axial protrusions, and the plurality of axial protrusions are fitted in a surrounding manner to the rotary output member and are radially engaged with same. The outer peripheral surface of the rotary output member comprises a plurality of side surfaces; a gap between each side surface and the housing is used for accommodating a pair of rolling members, and two adjacent pairs of rolling members are respectively arranged on two sides of an axial protrusion. The elastic components are used for driving the two rolling members of each pair to move away from each other and lock the rotary output member. The axial protrusions are used for driving rolling members of each pair to move toward each other and drive rotation of the rotary output member. By means of optimizing the internal structure of the rear wheel steering gear, the torque carrying capacity of the rear wheel steering gear is improved, thus improving the reliability.

Description

Rear wheel steering system with locking function and vehicle

[0001] This application claims priority to Chinese Patent Application No. 202411998639.3, filed with the China National Intellectual Property Administration on December 31, 2024, entitled “Rear Wheel Steering System and Vehicle with Locking Function”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of vehicle technology, specifically to a rear wheel steering system with locking function and a vehicle. Background Technology

[0003] The rear-wheel steering system controls the steering of the vehicle's rear wheels to reduce the vehicle's sideslip angle during steering, decrease the steady-state overshoot of the vehicle's yaw rate, and achieve smooth steering. Before and after a steering maneuver, the rear-wheel steering system is used to limit the rear-wheel steering to ensure normal vehicle movement. Summary of the Invention

[0004] This application provides a rear-wheel steering system with locking function and a vehicle. By optimizing the internal structure of the rear-wheel steering system, the torque-carrying capacity of the rear-wheel steering system is increased to improve reliability.

[0005] In a first aspect, this application provides a rear-wheel steering system with a locking function. The housing of the rear-wheel steering system accommodates a rotary input component, a rotary output component, multiple pairs of rolling elements, and multiple elastic components. The drive end of the rotary input component receives drive from a vehicle's steering motor. The coupling end of the rotary input component is driveably connected to the coupling end of the rotary output component. The drive end of the rotary output component is drively connected to a tie rod of at least one rear wheel in the vehicle. The coupling end of one of the rotary input components includes multiple axial protrusions, which surround and are spaced apart around the coupling end of the rotary output component. The rotary output component and each axial protrusion are radially interlocked. The outer peripheral surface of the coupling end of the rotary output component includes multiple side surfaces. The gap between each side surface and the housing accommodates a pair of rolling elements. Two adjacent pairs of rolling elements along the circumferential direction of the rotary output component are arranged on either side of an axial protrusion, with two rolling elements in each pair spaced apart between two axial protrusions. Each elastic component is used to drive two of the two rolling elements of a pair away from each other and lock the rotation of a rotary output element during the process of a rotary input element stopping rotation, and each axial protrusion is used to drive a pair of rolling elements closer to each other and drive the rotation of a rotary output element during the process of a rotary input element rotating.

[0006] The rear-wheel steering system provided in this application is driven by the transmission end of a rotary input component, which is connected to the motor shaft of the vehicle's steering motor. The coupling end of the rotary input component is also engaged with the coupling end of the rotary output component radially, thus achieving the effect of driving the steering motor shaft and the rotary output component through the rotary input component. The rear-wheel steering system can then transmit the drive power of the steering motor to the rotary output component. Furthermore, the rear-wheel steering system of this application is driven by the transmission end of the rotary output component, which is connected to the tie rod of at least one rear wheel in the vehicle. This allows the rotary output component to drive the tie rod to move axially along the tie rod, thereby changing the steering of at least one rear wheel of the vehicle. The rear-wheel steering system of this application thus drives the steering motor and the tie rod of at least one rear wheel.

[0007] The rear-wheel steering system provided in this application also achieves the effects of locking the rotation of the rotation output component while the rotation input component stops rotating, and driving the rotation output component to rotate synchronously while the rotation input component rotates, through the cooperation of the coupling end of the rotation input component, the coupling end of the rotation output component, multiple pairs of rolling elements, and multiple elastic components. Specifically, the coupling end of the rotation input component includes multiple axial protrusions, which, along with multiple pairs of rolling elements, alternately surround the outer circumferential surface of the coupling end of the rotation output component. While the rotation input component stops rotating, the multiple pairs of rolling elements receive the drive of each elastic component to move away from each other and abut against the same side of the rotation output component, thereby limiting the rotation of the rotation output component clockwise or counterclockwise in the circumferential direction. When the rear wheels of the vehicle are subjected to undesirable lateral forces, the rear-wheel steering system of this application can lock the tie rod by limiting the rotation of the rotation output component through multiple pairs of rolling elements, thereby limiting the sway of the rear wheels.

[0008] During the rotation of the rotary input component, multiple axial protrusions drive each pair of rolling elements to approach each other to release the locking state of each pair of rolling elements on the rotary output component. The coupling end of the rotary input component can then drive the coupling end of the rotary output component to rotate synchronously and drive the tie rod of at least one rear wheel.

[0009] The rear-wheel steering system provided in this application has multiple axial protrusions and multiple pairs of rolling elements arranged on the outer side of the rotary output element in its rotary input component. Given a fixed rear-wheel steering system volume, the rotary input component outputs a relatively large torque while driving the rotary output element to rotate synchronously. The multiple pairs of rolling elements also provide a relatively large torque when restricting the rotation of the rotary output element, thus improving the torque-carrying capacity of the rear-wheel steering system. The rear-wheel steering system provided in this application, while meeting the torque required to drive or lock the tie rod, achieves a relatively smaller overall size while ensuring reliable operation, thereby saving interior space in the vehicle.

[0010] In one implementation, each axial protrusion includes a radial groove, and each axial protrusion is used to accommodate the included angle formed by two adjacent sides through the radial groove so as to radially engage with a rotary output component.

[0011] In this implementation, each axial protrusion is nested radially within the included angle formed by two adjacent sides via a radial groove. During the rotation of a rotary input component, each axial protrusion abuts against one of the two adjacent sides via a groove wall of the radial groove, thereby driving the rotary output component to rotate synchronously.

[0012] In one implementation, the included angle between the two walls of the radial groove is less than or equal to the included angle formed by the two sides.

[0013] In this implementation, a gap is left between the axially protruding radial grooves and the two adjacent sides along the circumference of a rotary output component. The groove walls of each axially protruding radial groove need to rotate a certain angle with the rotary input component before abutting against one of the two adjacent sides. Setting the included angle between the two groove walls of the radial groove to be less than or equal to the included angle formed by the two sides can increase the contact area when the groove wall of the radial groove abuts against one of the two adjacent sides, improve the circumferential stress conditions of the rotary input and rotary output components, and enhance the torque carrying capacity of the rear wheel steering system.

[0014] In one implementation, the two groove walls of the radial groove in each axial protrusion are symmetrically arranged along the radius axis of the rotating output component.

[0015] In this implementation, along the circumference of the rotating output component, the inclination angle and offset distance of the two groove walls of each radial groove are equal. When each radial groove rotates clockwise or counterclockwise with the rotating input component, the contact angle and contact area of ​​the two groove walls pushing the two adjacent sides are equal, which helps to maintain the consistency of the torque output by the steering motor in both forward and reverse directions and simplifies the control logic of the steering motor.

[0016] In one implementation, each axial protrusion includes a radial protrusion and a further radial groove between two adjacent sides, wherein each axial protrusion is used to radially engage with a rotary output member by means of the radial protrusion embedding into the other radial groove.

[0017] In this implementation, each axial protrusion is radially embedded in another radial groove between two adjacent sides via a radial protrusion. During the rotation of a rotary input component, each axial protrusion abuts against a groove wall of another radial groove via a side wall of the radial protrusion to drive the rotary output component to rotate synchronously.

[0018] In one implementation, the included angle between the two sidewalls of the radial protrusion is less than or equal to the included angle between the two groove walls in another radial groove.

[0019] In this implementation, a gap exists between the radial protrusion of the axially protruding component and the groove wall of another radial groove along the circumference of one rotary output component. The sidewalls of the radial protrusions of each axially protruding component need to rotate a certain angle with the rotary input component before abutting against the groove wall of the other radial groove. Setting the included angle between the two sidewalls of the radial protrusion to be less than or equal to the included angle between the two groove walls of the other radial groove can increase the contact area between the sidewalls of the radial protrusion and the groove wall of the other radial groove, improve the circumferential stress conditions of the rotary input and rotary output components, and enhance the torque carrying capacity of the rear wheel steering system.

[0020] One implementation involves symmetrically arranging the two sidewalls of the radial protrusion in each axial protrusion along the radial axis of the rotating output component.

[0021] In this implementation, along the circumference of the rotary output component, the inclination angle and offset distance of the two sidewalls of each radial protrusion are equal. When each radial protrusion rotates clockwise or counterclockwise with the rotary input component, the contact angle and contact area of ​​the two sidewalls pushing the two groove walls of the other radial groove are equal, which helps to maintain the consistency of the torque output by the steering motor in both forward and reverse directions and simplifies the control logic of the steering motor.

[0022] In one implementation, two groove walls in another radial groove are arranged symmetrically along the radial axis of the rotating output component.

[0023] In this implementation, the inclination angle and offset distance of the two groove walls of the other radial groove are equal. When the two groove walls of the other radial groove receive the drive of the radial protrusion, the contact angle and contact area with the two side walls are equal. This makes it easy to maintain the consistency of the torque received by the rotating output component as the motor rotates forward and backward, thereby ensuring the consistency of the torque transmitted to the tie rod of the rear wheel and making it easier to control the rotation angle of the rear wheel.

[0024] In one implementation, along the circumference of a rotary output member, each axial protrusion includes a pair of circumferential sidewalls, two of which are directed toward two pairs of rolling elements arranged on either side of the axial protrusion, and each axial protrusion is used to drive a pair of rolling elements to approach each other via a circumferential sidewall during the rotation of a rotary input member.

[0025] In this implementation, along the circumference of a rotary output component, each axial protrusion abuts against one of two pairs of rolling elements arranged on both sides via a pair of circumferential sidewalls. As the rotary input component rotates clockwise or counterclockwise, one of the two circumferential sidewalls pushes one of the rolling elements in the pair of rolling elements closer to the other rolling element to release the locking state of the pair of rolling elements on the rotary output component.

[0026] One implementation involves symmetrically arranging two circumferential sidewalls of each axial protrusion along the radial axis of the rotating output component.

[0027] In this implementation, along the circumference of the rotary output component, the inclination angle and offset distance of a pair of circumferential sidewalls among the axial protrusions are equal. When the rotary input component rotates clockwise or counterclockwise, the contact angle and contact distance of each of the two circumferential sidewalls pushing one of the two pairs of rolling elements are equal, which facilitates the timing of the steering motor driving the rotary output component to rotate synchronously when it rotates forward and reverse, simplifying the control logic of the steering motor.

[0028] In one implementation, along the circumference of a rotating output component, the sum of the gaps between a pair of circumferential sidewalls of each axial protrusion and two pairs of rolling elements arranged on both sides of the axial protrusion is less than the circumferential gap at the radial engagement point between the axial protrusion and a rotating output component.

[0029] In this implementation, during the rotation of the rotary input component, the contact between the circumferential sidewall and the pair of rolling elements occurs before the axial protrusion drives the rotary output component to rotate. That is, the axial protrusion first pushes one of the rolling elements closer to the other to release the locking state of the rolling elements on the rotary output component, and then drives the rotary output component to rotate synchronously. This avoids the jamming phenomenon that might occur when the axial protrusion contacts the rotary output component first before pushing the pair of rolling elements.

[0030] In one implementation, each axial protrusion includes a radial groove, one of a pair of circumferential sidewalls is connected to the other through a groove wall of the radial groove, and the circumferential sidewall is parallel to the other groove wall.

[0031] In this implementation, each axial protrusion, as it rotates clockwise or counterclockwise with the rotary input component, abuts against a pair of rolling elements and a side surface via a circumferential sidewall and a groove wall, respectively. When one circumferential sidewall is parallel to the other groove wall, it is convenient to control the timing of each axial protrusion pushing the pair of rolling elements and abutting against a side surface, avoiding jamming caused by the other groove wall contacting a side surface before the circumferential sidewall contacts the pair of rolling elements.

[0032] In one implementation, each axial protrusion includes a radial protrusion. One of a pair of circumferential sidewalls along the circumference of the rotating output member is located on the same side of the axial protrusion as one sidewall of the radial protrusion, and the other circumferential sidewall is located on the opposite side of the axial protrusion as another sidewall of the radial protrusion. One circumferential sidewall is parallel to the first sidewall, and the other circumferential sidewall is parallel to the second sidewall.

[0033] In this implementation, as the rotary input component rotates clockwise or counterclockwise, each axial protrusion abuts against a pair of rolling elements arranged on the same side and a groove wall facing the same side, respectively, via a circumferential sidewall and a sidewall located on the same side. The circumferential sidewall and sidewall of each axial protrusion on the same side are parallel, facilitating control over the timing of each axial protrusion pushing the pair of rolling elements and abutting against a groove wall in the groove on the other side, thus avoiding jamming caused by one sidewall contacting a groove wall before the circumferential sidewall contacts the pair of rolling elements.

[0034] One implementation involves the radial protrusion in each axial protrusion having two sidewalls that extend through two circumferential sidewalls.

[0035] In this implementation, a pair of circumferential sidewalls in each axial protrusion extend radially along the rotary output component, and the portions of the two circumferential sidewalls radially embedded in another groove form the two sidewalls of the radial protrusion. That is, the two sidewalls in each axial protrusion are coplanar with the two circumferential sidewalls. This structure simplifies the shape of each axial protrusion and facilitates the machining of the rotary input component.

[0036] In one implementation, two adjacent axial protrusions include two opposing circumferential sidewalls, which are accommodated in the gap between the same side and the inner wall of the housing and arranged on both sides of a pair of rolling elements. The two opposing circumferential sidewalls are perpendicular to the direction in which the two rolling elements are arranged.

[0037] In this implementation, two pairs of rolling elements are arranged circumferentially around the rotary output component on both sides of an axial protrusion, and two axial protrusions are arranged on both sides of a pair of rolling elements. That is, multiple pairs of rolling elements and multiple axial protrusions alternately surround the outer circumferential surface of the rotary output component. Each of the two axial protrusions includes a circumferential sidewall acting on the same pair of rolling elements. Along the arrangement direction of the two rolling elements in a pair, the circumferential sidewalls of the two axial protrusions face each other. The two opposing circumferential sidewalls are perpendicular to the arrangement direction of the two rolling elements in a pair, which facilitates control of the spacing between the two circumferential sidewalls and the two rolling elements, thereby controlling the timing of each circumferential sidewall contacting and pushing a rolling element. This is beneficial for simultaneously releasing the locking state of multiple pairs of rolling elements on the rotary output component when each axial protrusion rotates clockwise or counterclockwise with the rotary input component.

[0038] In one implementation, along the circumference of a rotating output component, during the process of a rotating input component stopping its rotation, the distance between two opposing circumferential sidewalls is greater than the width of a pair of rolling elements between the opposing circumferential sidewalls.

[0039] In this implementation, along the circumference of a rotating output component, the distance between two opposing circumferential sidewalls is greater than the sum of the distance between a pair of rolling elements and the diameters of the two rolling elements. That is, the two opposing circumferential sidewalls are spaced apart from the pair of rolling elements. This prevents any circumferential sidewall from contacting a rolling element and affecting the locking effect of the pair of rolling elements on one side.

[0040] In one implementation, along a direction perpendicular to the arrangement of the two rolling elements in a pair, the height dimension of the two opposite circumferential sidewalls is greater than or equal to the radius of each rolling element in the pair.

[0041] In this implementation, the height of each circumferential sidewall exceeds the radius of the rolling element, thereby ensuring that each axial protrusion abuts against the middle of the rolling element during the rotation of the rotary input element. This facilitates pushing one rolling element toward another and makes it easier to control the timing of contact between each circumferential sidewall and the rolling element.

[0042] One implementation involves two opposing circumferential sidewalls arranged symmetrically along the radial axis of the rotating output component.

[0043] In this implementation, the two opposing circumferential sidewalls of the two axial protrusions are symmetrically arranged with respect to the radius of the rotary output component. The distances between the two opposing circumferential sidewalls and the radius of the rotary output component are equal, which facilitates the control of the interval distance between the two circumferential sidewalls and the two rolling components. This also helps to synchronize the timing of the release of the locking state of multiple pairs of rolling components on the rotary output component when each axial protrusion rotates clockwise or counterclockwise with the rotary input component, simplifying the control logic of the steering motor.

[0044] One implementation method involves making each side a plane.

[0045] In this implementation, each side of the coupling end of the rotating output component is defined as a plane, which facilitates the machining of each side.

[0046] One implementation involves the sides being evenly distributed along the circumference of the rotating output component.

[0047] In this implementation, during the process of the rotary input component stopping rotation, the locking forces of each pair of rolling elements on each side are relatively evenly distributed around the outer circumference of the rotary output component. This can improve the stress situation at the coupling end of the rotary output component and prevent deformation of the coupling end of the rotary output component due to uneven stress.

[0048] One implementation is that each side is symmetrical about the radius axis of a rotating output component.

[0049] In this implementation, each side is symmetrical along the radius axis of the rotating output component, which facilitates the reception of the supporting force of a pair of rolling elements on each side to limit the rotation of the rotating output component. The supporting forces of the two rolling elements acting on the sides are relatively balanced, and the locking force of the rear wheel steering gear provided in this application for the clockwise or counterclockwise rotation of the tie rod of the rear wheel tends to be consistent.

[0050] One implementation involves symmetrically arranging two adjacent sides along the radius axis of a rotating output component.

[0051] In this implementation, two adjacent sides are symmetrically arranged along the radius axis of a rotating output component, so that after the two adjacent sides are radially engaged with the axial protrusion, the torque received by the motor in forward and reverse rotation is consistent, thereby ensuring that the torque transmitted to the tie rod of the rear wheel is consistent, which facilitates the control of the rotation angle of the rear wheel.

[0052] In one implementation, the coupling end of the rotating output component is square.

[0053] In one implementation, the coupling end of the rotating output component is an equilateral triangle.

[0054] In both implementations described above, the number of sides on the coupling end of the rotary output component is smaller, and the area of ​​each side is relatively larger, thus providing better load-bearing capacity. During the process of the rotary output component stopping rotation, each side can receive greater pressure from multiple pairs of rolling elements to limit the rotation of the rotary output component.

[0055] One implementation involves arranging each elastic component between two of a pair of rolling elements along the circumference of a rotating output element.

[0056] In this implementation, each elastic component can abut against two rolling elements at both ends to drive the two rolling elements away from each other. The elastic components can also be housed together with the pair of rolling elements in the gap between the side and the inner wall of the housing, eliminating the need to provide separate housing space for the elastic components, thereby reducing the overall size of the rear wheel steering system provided in this application.

[0057] In one implementation, each side includes a fixing groove, the opening of each fixing groove facing the inner wall of the housing along the radial direction of a rotating output member, and each fixing groove is used to fix an elastic component.

[0058] In this implementation, an elastic component is arranged circumferentially between two rolling components along the rotary output component. The elastic component is positioned radially along the rotary output component by being embedded in a fixing groove on its side. The fixing groove also serves to limit the orientation of the elastic component between the two rolling components, preventing deformation or displacement of the elastic component from affecting the relative displacement between the two rolling components.

[0059] In one implementation, each elastic component is a U-shaped spring, which includes two spring pieces and a U-shaped connecting end. The U-shaped connecting end is used to be embedded in the side and to connect the two spring pieces. The two spring pieces are used to abut against the two rolling elements in a pair of rolling elements respectively.

[0060] In this implementation, the U-shaped spring has a small structure, is easy to install and fix, and is not easily deformed, which can effectively drive the two rolling elements to move away from each other. Each spring of the U-shaped spring is used to abut against one rolling element. When one spring is deformed by the compression of one rolling element, the shape of the other spring remains relatively stable. When the rotary input component rotates clockwise or counterclockwise with the steering motor, the two springs deform alternately, which can improve the reliability of the elastic component and extend its service life.

[0061] In one implementation, the bending radius of the U-shaped connecting end of the U-shaped spring is smaller than the spacing between the two springs.

[0062] In this implementation, the U-shaped connecting end is used to embed into the side. The U-shaped connecting end is relatively large in size when embedded into the side, so that the U-shaped spring can be better embedded into the side and prevent it from falling off, thereby improving the reliability of the connection between the elastic component and the side.

[0063] In one implementation, the length of each spring protruding from the side is greater than the radius of the rolling element that abuts against the spring.

[0064] In this implementation, the length of each spring exceeds the radius of the rolling element, thereby ensuring that the two springs abut against the middle of the two rolling elements respectively, which facilitates the springs to push the two rolling elements away from each other and reduce the overall size of the elastic component.

[0065] In one implementation, the inner wall of the housing is a circumferential surface. During the process of a rotary input component stopping its rotation, each elastic component is used to drive two of a pair of rolling elements to abut against the inner wall of the housing and the same side surface respectively to lock the rotation of a rotary output component.

[0066] In this implementation, the gaps between the inner wall of the housing and each side are crescent-shaped. Each gap is larger in the middle and gradually narrows towards the sides along the radial dimension of the rotating output component. When the two rolling elements move away from each other, each rolling element abuts against the inner wall and side of the housing, restricting the rotational movement of the rotating output component in one direction. Two of the rolling elements in a pair abut against the inner wall and the same side of the housing, thereby restricting the rotational movement of the rotating output component in clockwise and counterclockwise directions relative to each other. This rear-wheel steering system of the present application thus forms the effect of two tandem one-way clutches, reducing the overall size of the rear-wheel steering system and saving interior space in the vehicle.

[0067] One implementation involves two cylindrical rolling elements in a pair, with the cylindrical central axis of each rolling element parallel to the axial direction of a rotating output element, and the cylindrical diameters of the two rolling elements being equal.

[0068] In this implementation, the cylindrical rolling elements form larger contact surfaces with the side surfaces and the inner wall of the housing, thereby improving the load-bearing capacity of the rear wheel steering system of this application. The two rolling elements have equal diameters, and the distance between them and the radius of the rotary output component is equal. The torque of the abutment force exerted by each rolling element on the side surface is also relatively consistent. Therefore, during the process of the rotary input component stopping rotation, the locking force of the two rolling elements on the rotary output component rotating clockwise or counterclockwise is relatively consistent, which improves the reliability of the rear wheel steering system of this application.

[0069] In one implementation, the housing of a rear-wheel steering system includes an input-side housing and an output-side housing, which are arranged adjacent to each other along the axial direction of the rear-wheel steering system. The output-side housing encloses one of the input-side housings. One of the input-side housings is used to secure the outer ring of a bearing, and the inner ring of the bearing is used to secure the drive end of a rotary input component. The output-side housing is used to secure the outer ring of another bearing, and the inner ring of the other bearing is used to secure the drive end of a rotary output component.

[0070] In this implementation, the housing of a rear wheel steering unit also accommodates two bearings. Each bearing supports either the rotary input or rotary output component to ensure smooth rotation of the rotary input and rotary output components about the axis of the rear wheel steering unit.

[0071] In one implementation, the output-side housing includes a mounting surface with multiple bolt holes, each for passing a bolt through. The input-side housing includes another mounting surface for securing the output-side housing, and this other mounting surface includes multiple bolt slots, each for securing and receiving a bolt passing through a bolt hole.

[0072] In one implementation, a rotary output component is connected to a tie rod via a drive shaft. The axis of one drive shaft is parallel to the axis of one tie rod. Along the radial direction of a rear-wheel steering unit, another drive shaft is spaced apart from the tie rod. Along the axial direction of a rear-wheel steering unit, the end of one drive shaft away from a steering motor is used to connect to the middle section of the tie rod via a transmission element. During rotation of one steering motor, one drive shaft drives the tie rod to move axially along its length via the transmission element. When one steering motor stops rotating, a rear-wheel steering unit limits the axial movement of the tie rod by restricting the rotation of the transmission element driven by the drive shaft.

[0073] In this implementation, a drive shaft is parallel to the axis of a tie rod, which can reduce the radial dimension of the rear wheel steering gear provided in this application and compress the volume of a transmission component, making it easier to arrange and assemble the rear wheel steering gear.

[0074] In one implementation, a transmission component includes a drive wheel and a threaded sleeve. The drive wheel is fixed to an end of a drive shaft along the axial direction of a rear wheel steering gear, away from a steering motor. The inner circumferential surface of the threaded sleeve engages with the outer circumferential surface of a middle section of a tie rod. A drive wheel, with a diameter smaller than that of the threaded sleeve, is used for drive connection to the outer circumferential surface of the threaded sleeve along the radial direction of the rear wheel steering gear.

[0075] In this implementation, the diameter of a drive wheel is smaller than the diameter of a threaded sleeve, and a transmission component creates a deceleration effect from a drive shaft toward a threaded sleeve. During the rotation of a steering motor, a transmission component reduces the rotational speed of a threaded sleeve and amplifies the driving force output by the steering motor. When the two rear wheels exhibit unintended steering, a transmission component reduces the reverse driving force exerted by a tie rod on a drive shaft, thereby allowing a rear-wheel steering system to limit the rotation of a drive shaft.

[0076] In one implementation, a tie rod includes a threaded section in its axial middle section, and the inner circumferential surface of a threaded sleeve is used to engage with the threaded section. The threaded sleeve is driven by a drive wheel to rotate about the axis of the tie rod, while simultaneously driving the tie rod to move axially.

[0077] In one implementation, a plurality of balls are included between the inner circumferential surface of a threaded sleeve and a threaded section. The plurality of balls are used to reduce the friction between a threaded sleeve and a tie rod, thereby improving the transmission efficiency of the rear wheel steering system provided in this application.

[0078] In this implementation, because the rear wheel steering system of this application limits the axial displacement of a tie rod through a rear wheel steering system, it eliminates the need for a transmission component to limit the axial displacement of a tie rod through internal friction to reduce the intervention frequency of the steering motor. Therefore, the transmission efficiency of a transmission component can be improved to reduce the power consumption of a steering motor during rotation.

[0079] Secondly, this application provides a vehicle including one or more rear wheels and a rear-wheel steering system provided in any of the above implementations. The rear-wheel steering system is used to drive one or more rear wheels to change steering. The vehicle of this application, while possessing rear-wheel steering functionality, increases load-bearing capacity and improves reliability. Attached Figure Description

[0080] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0081] Figure 1 is a schematic diagram of the exterior structure of a vehicle provided in an embodiment of this application;

[0082] Figure 2 is a partial structural schematic diagram of a vehicle provided in one embodiment of this application;

[0083] Figure 3 is a structural schematic diagram of a rear wheel steering system provided in an embodiment of this application;

[0084] Figure 4 is a cross-sectional structural schematic diagram of a rear wheel steering system provided in an embodiment of this application;

[0085] Figure 5 is a partial cross-sectional structural schematic diagram of a rear wheel steering system provided in an embodiment of this application;

[0086] Figure 6 is a structural schematic diagram of a rear wheel steering system provided in an embodiment of this application;

[0087] Figure 7 is a partial structural schematic diagram of a rear wheel steering system provided in one embodiment of this application;

[0088] Figure 8 is a partially exploded structural diagram of a rear wheel steering system provided in one embodiment of this application;

[0089] Figure 9 is a cross-sectional structural schematic diagram of a rear wheel steering system provided in an embodiment of this application;

[0090] Figure 10 is a partial structural schematic diagram of a rear wheel steering system provided in an embodiment of this application;

[0091] Figure 11 is a partial structural schematic diagram of a rear wheel steering system provided in an embodiment of this application;

[0092] Figure 12 is a cross-sectional structural schematic diagram of a rear wheel steering system provided in an embodiment of this application;

[0093] Figure 13 is a partial structural schematic diagram of a rear wheel steering system provided in one embodiment of this application;

[0094] Figure 14 is a partial structural schematic diagram of a rear wheel steering system provided in one embodiment of this application;

[0095] Figure 15 is a cross-sectional structural schematic diagram of a rear wheel steering system provided in an embodiment of this application;

[0096] Figure 16 is a schematic diagram of the structure of a rear wheel steering system provided in an embodiment of this application;

[0097] Figure 17 is a schematic diagram of the structure of a rear wheel steering system provided in an embodiment of this application;

[0098] Figure 18 is a cross-sectional structural schematic diagram of a rear wheel steering system provided in an embodiment of this application;

[0099] Figure 19 is a schematic diagram of the structure of a rear wheel steering system provided in an embodiment of this application;

[0100] Figure 20 is a structural schematic diagram of a rear wheel steering system provided in one embodiment of this application;

[0101] Figure 21 is a cross-sectional structural schematic diagram of a rear wheel steering system provided in an embodiment of this application;

[0102] Figure 22 is a partial structural schematic diagram of a rear wheel steering system provided in one embodiment of this application;

[0103] Figure 23 is a partial structural schematic diagram of a rear wheel steering system provided in one embodiment of this application;

[0104] Figure 24 is a partial structural schematic diagram of a rear wheel steering system provided in one embodiment of this application;

[0105] Figure 25 is a partial structural schematic diagram of a rear wheel steering system provided in one embodiment of this application;

[0106] Figure 26 is a partial structural schematic diagram of a rear wheel steering system provided in one embodiment of this application;

[0107] Figure 27 is a partial structural schematic diagram of a rear wheel steering system provided in one embodiment of this application;

[0108] Figure 28 is a partial structural schematic diagram of a rear wheel steering system provided in one embodiment of this application;

[0109] Figure 29 is a partial structural schematic diagram of a rear wheel steering system provided in one embodiment of this application;

[0110] Figure 30 is a partial structural schematic diagram of a rear wheel steering system provided in one embodiment of this application;

[0111] Figure 31 is a partial structural schematic diagram of a rear wheel steering system provided in one embodiment of this application.

[0112] Reference numerals: 1000-Vehicle; 1001-Frame; 1002-Rear wheel; 1003-Front wheel; 1004-Steering knuckle; 200-Rear wheel steering gear; 10-Steering motor; 11-Motor shaft; 20-Transmission mechanism; 211-Drive shaft; 221-Transmission component; 2211-Sleeve; 2212-Drive wheel; 30-Tie rod; 31-Threaded section; 32-Ball bearing; 40-Housing; 41-Input side housing; 411-Bolt groove; 42-Output side housing; 421-Bolt hole; 43-Bolt; 44-Limiting ring; 45-Circumferential surface; 50-Rotary input component; 51-First transmission end; 52-First coupling end; 53-Axial protrusion; 53a-First axial protrusion; 53b-Second axial protrusion; 54-First radial groove; 541-First groove wall; 542-Second groove wall; 55-Radial groove 551-First sidewall; 552-Second sidewall; 56-Circumferential sidewall; 561-First circumferential sidewall; 562-Second circumferential sidewall; 563-Third circumferential sidewall; 564-Fourth circumferential sidewall; 60-Rotary output component; 61-Second transmission end; 62-Second coupling end; 63-Side surface; 631-First side surface; 632-Second side surface; 64-Second radial groove; 641-Third groove wall; 642-Fourth groove wall; 65-Fixing groove; 70-Rolling element; 71-First pair of rolling elements; 711-First rolling element; 712-Second rolling element; 72-Second pair of rolling elements; 721-Third rolling element; 722-Fourth rolling element; 80-Elastic component; 81-Spring; 811-First segment; 812-Second segment; 82-U-shaped connecting end; 90-Bearing; 91-Outer ring; 92-Inner ring. Detailed Implementation

[0113] The technical solutions of the embodiments of this application will now be described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0114] This application provides a rear-wheel steering system with a locking function. The housing of the rear-wheel steering system accommodates a rotary input component, a rotary output component, multiple pairs of rolling elements, and multiple elastic components. The drive end of the rotary input component receives drive from the vehicle's steering motor. The coupling end of the rotary input component is drively connected to the coupling end of the rotary output component. The drive end of the rotary output component is drively connected to the tie rod of at least one rear wheel in the vehicle. The coupling end of one of the rotary input components includes multiple axial protrusions, which are spaced apart around the coupling end of the rotary output component. The rotary output component and each axial protrusion are radially interlocked. The outer peripheral surface of the coupling end of the rotary output component includes multiple side surfaces. The gap between each side surface and the housing accommodates a pair of rolling elements. Two adjacent pairs of rolling elements along the circumferential direction of the rotary output component are arranged on both sides of an axial protrusion, with two rolling elements in each pair spaced apart between two axial protrusions. Each elastic component is used to drive two of the two rolling elements of a pair away from each other and lock the rotation of a rotary output element during the process of a rotary input element stopping rotation, and each axial protrusion is used to drive a pair of rolling elements closer to each other and drive the rotation of a rotary output element during the process of a rotary input element rotating.

[0115] The rear-wheel steering system provided in this application has multiple axial protrusions and multiple pairs of rolling elements arranged on the outer side of the rotary output element in its rotary input component. Given a fixed rear-wheel steering system volume, the rotary input component outputs a relatively large torque while driving the rotary output element to rotate synchronously. The multiple pairs of rolling elements also provide a relatively large torque when restricting the rotation of the rotary output element, thus improving the torque-carrying capacity of the rear-wheel steering system. The rear-wheel steering system provided in this application, while meeting the torque required to drive or lock the tie rod, achieves a relatively smaller overall size while ensuring reliable operation, thereby saving interior space in the vehicle.

[0116] This application provides a vehicle including one or more rear wheels and the aforementioned rear-wheel steering system. The rear-wheel steering system is used to drive one or more rear wheels to change steering. The vehicle of this application, while possessing rear-wheel steering functionality, increases load-bearing capacity and improves reliability.

[0117] Please refer to Figure 1, which shows a schematic diagram of the external structure of a vehicle 1000 provided in one embodiment of this application.

[0118] In one embodiment, the vehicle 1000 provided in this application includes a frame 1001, two rear wheels 1002, two front wheels 1003, and a rear-wheel steering unit 200. The frame 1001 is used to rotatably connect the two rear wheels 1002 and the two front wheels 1003. The rear-wheel steering unit 200 is used to fix to the frame 1001 and is drively connected to the two rear wheels 1002 of the vehicle 1000. The rear-wheel steering unit 200 is used to drive the two rear wheels 1002 of the vehicle 1000 to change steering, thereby expanding the control range of the steering angle of the vehicle 1000 and reducing the occurrence of understeer or oversteer of the vehicle 1000.

[0119] In some scenarios, when vehicle 1000 needs to turn or make a U-turn with a small turning radius, the turning radius can be reduced and the vehicle's agility improved by controlling the front wheels 1003 and rear wheels 1002 to rotate in opposite directions. In other scenarios, when vehicle 1000 needs to corner at a certain speed, the front wheels 1003 and rear wheels 1002 can be controlled to rotate in the same direction, thereby reducing the vehicle's sideslip angle and the steady-state overshoot of its yaw rate, thus enhancing the vehicle's handling stability.

[0120] It should be noted that the number of front wheels 1003 and rear wheels 1002 of the vehicle 1000 provided in this application includes, but is not limited to, two. For example, in another embodiment, the vehicle 1000 provided in this application may have multiple front wheels 1003 and multiple rear wheels 1002, and the rear wheel steering unit 200 is connected to a plurality of the multiple rear wheels 1002 in a transmission connection and is used to drive the plurality of rear wheels 1002 to change steering.

[0121] Please refer to Figures 2 and 3. Figure 2 is a partial structural schematic diagram of a vehicle 1000 provided in one embodiment of this application; Figure 3 is a structural schematic diagram of a rear wheel steering system 200 provided in one embodiment of this application.

[0122] As shown in Figures 2 and 3, the rear-wheel steering system 200 provided in this application includes a steering motor 10, a transmission mechanism 20, and a tie rod 30. The steering motor 10 drives the tie rod 30 via the transmission mechanism 20 to steer one or both rear wheels 1002. The steering motor 10 is fixed to the frame 1001, and the motor shaft 11 of the steering motor 10 is parallel to the axial direction of the rear wheels 1002. The tie rod 30 is slidably connected to the frame 1001 along the axial direction parallel to the rear wheels 1002, and extends along the axial direction parallel to the rear wheels 1002. In one embodiment, one end of the tie rod 30 along the axial direction is connected to a rear wheel 1002 via a steering knuckle 1004. In another embodiment, both ends of the tie rod 30 along the axial direction are connected to a rear wheel 1002 via a steering knuckle 1004. The transmission mechanism 20 is used to drive the steering motor 10 and the tie rod 30 to receive the driving force of the steering motor 10 and drive the tie rod 30 to move along its own axial direction, thereby causing the rear wheel 1002 to deflect relative to the frame 1001 and realize the steering of the rear wheel 1002.

[0123] Please refer to Figures 4 and 5. Figure 4 is a cross-sectional view of the rear wheel steering system 200 provided in one embodiment of this application; Figure 5 is a partial cross-sectional view of the rear wheel steering system 200 provided in one embodiment of this application.

[0124] In one embodiment, the transmission mechanism 20 includes a drive shaft 211 through which the transmission mechanism 20 receives the driving force from the steering motor 10. The axis of the drive shaft 211 is parallel to the axis of the tie rod 30. The drive shaft 211 is spaced apart from the tie rod 30 along the radial direction of the rear wheel steering unit 200. Along the axial direction of the rear wheel steering unit 200, the end of the drive shaft 211 away from the steering motor 10 is used to drive the middle section of the tie rod 30 via a transmission member 221. During rotation of the motor shaft 11 of the steering motor 10, the drive shaft 211 drives the tie rod 30 to move axially along its own axis via the transmission member 221. When the motor shaft 11 of the steering motor 10 is not rotating, the rear wheel steering unit 200 restricts the axial movement of the tie rod 30 by limiting the rotation of the transmission member 221 driven by the drive shaft 211.

[0125] In this embodiment, the drive shaft 211 is parallel to the axis of the tie rod 30, which can reduce the radial dimension of the rear wheel steering gear 200 provided in this application and compress the volume of the transmission component 221, making it easier to arrange and assemble the rear wheel steering gear 200 of this application.

[0126] In one embodiment, the transmission component 221 includes a threaded sleeve 2211 and a transmission wheel 2212. The inner circumferential surface of the threaded sleeve 2211 engages with the outer circumferential surface of the middle section of the tie rod 30. The transmission wheel 2212 is fixed to the end of the drive shaft 211 along the axial direction of the rear wheel steering gear 200 away from the steering motor 10. Along the radial direction of the rear wheel steering gear 200, the transmission wheel 2212 is used to drive the outer circumferential surface of the threaded sleeve 2211, and the diameter of the transmission wheel 2212 is smaller than the diameter of the threaded sleeve 2211.

[0127] Therefore, the rotation of the steering motor 10 drives the drive shaft 211 to rotate, and the drive wheel 2212 rotates with the drive shaft 211, driving the threaded sleeve 2211 to rotate, so that the tie rod 30 can be displaced along its own axial direction. At the same time, the transmission component 221 can create a deceleration effect from the drive shaft 211 toward the threaded sleeve 2211. During the rotation of the steering motor 10, the transmission component 221 can reduce the rotational speed of the threaded sleeve 2211 and amplify the driving force output by the steering motor 10, so as to effectively ensure the lateral displacement of the tie rod 30 under the drive of the threaded sleeve 2211. When the two rear wheels 1002 produce unexpected steering, the transmission component 221 is used to reduce the reverse driving force of the tie rod 30 on the drive shaft 211, so that the rear wheel steering system 200 provided in this application can limit the rotation of the drive shaft 211.

[0128] In one embodiment, the tie rod 30 includes a threaded section 31, and the internal thread of the inner circumferential surface of the threaded sleeve 2211 engages with the threaded section 31. The threaded sleeve 2211 is driven by the drive wheel 2212 and rotates relative to the tie rod 30 about its axis, while simultaneously pulling the tie rod 30 to move axially, thereby enabling the rear wheel 1002 to steer. The engagement of the threaded sleeve 2211 with the threaded section 31 of the tie rod 30 ensures the reliability of the drive component 221 in driving the tie rod 30 to move axially.

[0129] In one embodiment, the inner circumferential surface of the threaded sleeve 2211 and the threaded section 31 include a plurality of balls 32. The plurality of balls 32 are used to reduce the friction between the threaded sleeve 2211 and the tie rod 30, so as to improve the transmission efficiency of the rear wheel steering gear 200 of this application.

[0130] Since the rear wheel steering system 200 of this application restricts the rotation of the transmission shaft 211 to drive the transmission component 221, thereby limiting the axial displacement of the tie rod 30, the transmission component 221 is exempt from limiting the axial displacement of the tie rod 30 through internal friction to reduce the intervention frequency of the steering motor 10. Therefore, the transmission efficiency of the transmission component 221 can be improved to reduce the power consumption of the steering motor 10 during rotation.

[0131] In one embodiment, the transmission method between the transmission wheel 2212 and the threaded sleeve 2211 may include any one or more combinations of belt drive, chain drive, gear drive, rack and pinion drive, etc., to ensure that the driving force of the transmission wheel 2212 can be reliably transmitted to the threaded sleeve 2211, and that the threaded sleeve 2211 can rotate around the axis of the tie rod 30 to drive the tie rod 30 to move along its own axial direction. This application does not make any special limitation in this regard.

[0132] Please refer to Figures 6 to 9. Figure 6 is a structural schematic diagram of the rear wheel steering system 200 provided in one embodiment of this application; Figure 7 is a partial structural schematic diagram of the rear wheel steering system 200 provided in one embodiment of this application; Figure 8 is a partial exploded structural schematic diagram of the rear wheel steering system 200 provided in one embodiment of this application; and Figure 9 is a cross-sectional structural schematic diagram of the rear wheel steering system 200 provided in one embodiment of this application.

[0133] The rear-wheel steering system 200 provided in this application includes a housing 40, a rotary input component 50, and a rotary output component 60. The housing 40 houses the rotary input component 50 and the rotary output component 60. The rotary input component 50 is used to drive the motor shaft 11 of the steering motor 10 and the rotary output component 60, and the rotary output component 60 is used to drive the tie rods 30 of one or both rear wheels 1002. The rear-wheel steering system 200 provided in this application achieves the effect of driving the connection between the motor shaft 11 of the steering motor 10 and the tie rods 30 through the rotary input component 50 and the rotary output component 60.

[0134] In one embodiment, the rotating output component 60 is connected to the crossbar 30 of one or two rear wheels 1002 via the drive shaft 211 of the transmission mechanism 20.

[0135] The rotary input component 50 includes opposing transmission ends and coupling ends along its own axial direction. In this embodiment, the transmission end and coupling end of the rotary input component 50 are defined as a first transmission end 51 and a first coupling end 52, respectively. The first transmission end 51 is used to receive the drive from the steering motor 10 of the vehicle 1000, and the first coupling end 52 is used to drive the rotary output component 60. Specifically, the rotary output component 60 includes opposing transmission ends and coupling ends along its own axial direction. In this embodiment, the transmission end and coupling end of the rotary output component 60 are defined as a second transmission end 61 and a second coupling end 62, respectively. The second coupling end 62 is used to drive the first coupling end 52, and the second transmission end 61 is used to drive the tie rods 30 of one or two rear wheels 1002 in the vehicle 1000. Thus, the rear wheel steering system 200 provided in this application can drive the motor shaft 11 of the steering motor 10 and the tie rods 30 through the rotary input component 50 and the rotary output component 60.

[0136] Please refer to Figures 10 to 12. Figure 10 is a partial structural schematic diagram of the rear wheel steering system 200 provided in one embodiment of this application; Figure 11 is a partial structural schematic diagram of the rear wheel steering system 200 provided in one embodiment of this application; and Figure 12 is a cross-sectional structural schematic diagram of the rear wheel steering system 200 provided in one embodiment of this application.

[0137] The first coupling end 52 includes a plurality of axial protrusions 53, each extending axially along the rotary output member 60. Along the circumference of the rotary output member 60, the plurality of axial protrusions 53 surround the outer peripheral surface of the second coupling end 62 and are spaced apart. Along the radial direction of the rotary output member 60, each axial protrusion 53 is used to engage with the outer peripheral surface of the second coupling end 62 of the rotary output member 60. This achieves the effect of a transmission connection between the rotary input member 50 and the rotary output member 60.

[0138] When the rear wheel steering system 200 provided in this application outputs driving force through the steering motor 10, the motor shaft 11 of the steering motor 10 rotates to drive the first transmission end 51 of the rotary input member 50 to rotate around the axis of the rotary output member 60. The first coupling end 52 of the rotary input member 50 is used to drive a plurality of axial protrusions 53 to rotate around the axis of the rotary output member 60. Because each axial protrusion 53 along the radial direction of the rotary output member 60 is used to engage with the outer peripheral surface of the second coupling end 62 of the rotary output shaft, the rotation of the plurality of axial protrusions 53 drives the second coupling end 62 of the rotary output member 60 to rotate around the axis of the rotary output member 60. The second transmission end 61 of the rotary output member 60 rotates with the second coupling end 62 around the axis of the rotary output member 60, and drives the tie rod 30 to displace along its own axial direction, thereby causing the rear wheel 1002 to deflect relative to the frame 1001 to achieve steering.

[0139] Please refer to Figures 13 and 15. Figure 13 is a partial structural schematic diagram of the rear wheel steering system 200 provided in one embodiment of this application; Figure 14 is a partial structural schematic diagram of the rear wheel steering system 200 provided in one embodiment of this application; and Figure 15 is a cross-sectional structural schematic diagram of the rear wheel steering system 200 provided in one embodiment of this application.

[0140] The outer peripheral surface of the second coupling end 62 includes multiple side surfaces 63, or it can be understood that multiple side surfaces 63 surround the outer peripheral surface of the second coupling end 62. The gap between each side surface 63 and the housing 40 is used to accommodate a pair of rolling elements 70. That is, the rear wheel steering gear 200 provided in this application includes multiple pairs of rolling elements 70, which are accommodated within the housing 40. Along the radial direction of the rotary output member 60, each pair of rolling elements 70 is located between a side surface 63 of the second coupling end 62 and the inner wall of the housing 40. Along the circumferential direction of the rotary output member 60, two adjacent pairs of rolling elements 70 are respectively arranged on both sides of an axial protrusion 53, and the two rolling elements 70 in each pair are spaced apart between two axial protrusions 53. Alternatively, it can be understood that multiple axial protrusions 53 and multiple pairs of rolling elements 70 alternately surround the outer peripheral surface of the second coupling end 62 along the circumferential direction of the rotary output member 60.

[0141] The rear-wheel steering system 200 provided in this application also includes a plurality of elastic components 80, which are housed within a housing 40. When the rotary input 50 stops rotating, that is, when the motor shaft 11 of the steering motor 10 is not rotating, two of the rolling elements 70 in each pair are driven apart by one of the elastic components 80 to lock the rotation of the rotary output 60. During the rotation of the rotary input 50, that is, during the rotation of the motor shaft 11 of the steering motor 10, two of the rolling elements 70 in each pair are also driven closer together by an axial protrusion 53 to drive the rotation of the rotary output 60.

[0142] When the vehicle 1000 travels on an uneven road surface, causing the two rear wheels 1002 to turn unexpectedly, the rear wheel steering system 200 provided in this application can limit the axial displacement of the tie rod 30 to limit the angle at which the two rear wheels 1002 turn unexpectedly, ensuring that the vehicle 1000 travels smoothly. Specifically, when the rear wheels 1002 are impacted by the ground and turn unexpectedly, the rear wheels 1002 will reverse the axial displacement of the tie rod 30, thereby driving the rotary output member 60 to rotate in the opposite direction. When the motor shaft 11 of the steering motor 10 is not rotating, that is, when the rotary input member 50 stops rotating, the rear wheel steering system 200 drives the two rolling elements 70 in each pair of rolling elements 70 to move away from each other through the elastic component 80 and abut against the same side 63 of the second coupling end 62, thereby limiting the rotation of the rotary output member 60 in a circumferential clockwise or counterclockwise direction to lock the rotation of the rotary output member 60. At the same time, the axial displacement of the tie rod 30 is limited by the rotating output component 60, thereby limiting the steering angle of the rear wheel 1002 when it turns unexpectedly, and limiting the sway of the rear wheel 1002.

[0143] During this process, the motor shaft 11 of the steering motor 10 does not need to rotate. Therefore, the rear wheel steering system 200 provided in this application can reduce the frequency of the steering motor 10 intervening to limit the unintended steering of the rear wheel 1002. This avoids the phenomenon of limiting the unintended steering of the rear wheel 1002 by driving the steering motor 10 to operate in a stalled state for a long time. This extends the service life of the steering motor 10.

[0144] During the steering process of the rear wheel 1002 driven by the steering motor 10 in this application, the motor shaft 11 of the steering motor 10 rotates and drives the rotary input component 50 to rotate. The rear wheel steering device 200 provided in this application drives two of the rolling elements 70 in each pair of rolling elements 70 to approach each other through the axial protrusion 53. The two rolling elements 70 no longer simultaneously abut against the same side 63 of the second coupling end 62, and the locking of the multiple pairs of rolling elements 70 to the rotary output component 60 is released. Since the axial protrusion 53 of the rotary input component 50 is embedded with the outer peripheral surface of the second coupling end 62 of the rotary output component 60, the rotation of the rotary input component 50 can drive the rotary output component 60 to rotate synchronously, thereby driving the tie rod 30 to move along its own axial direction, thereby causing the rear wheel 1002 to deflect relative to the frame 1001, and realizing steering.

[0145] It should be noted that the movement of two rolling elements 70 away from each other in each pair can be understood as the two rolling elements 70 moving simultaneously in opposite directions; or it can be understood as one of the two rolling elements 70 moving away from the other while the other remains stationary. Similarly, the movement of two rolling elements 70 approaching each other in each pair can be understood as the two rolling elements 70 moving simultaneously in opposite directions; or it can be understood as one of the two rolling elements 70 moving closer to the other while the other remains stationary.

[0146] The rear wheel steering system 200 provided in this application achieves the effect of driving the rotation output component 60 to rotate synchronously during the rotation of the rotation input component 50 through the cooperation of the first coupling end 52 of the rotation input component 50, the second coupling end 62 of the rotation output component 60, multiple pairs of rolling elements 70, and multiple elastic components 80, thereby realizing the steering of the rear wheel 1002; at the same time, it can also lock the rotation of the rotation output component 60 when the rotation of the rotation input component 50 stops rotating, thereby limiting the sway of the rear wheel 1002 when the rear wheel 1002 of the vehicle 1000 is subjected to an undesirable lateral force, and ensuring the smooth driving of the vehicle 1000.

[0147] Furthermore, the multiple axial protrusions 53 and multiple pairs of rolling elements 70 of the rotary input component 50 of the rear wheel steering system 200 provided in this application are all arranged on the outer side of the second coupling end 62 of the rotary output component 60. That is, the points of action of the rotary input component 50 and the rolling elements 70 on the rotary output component 60 are all located on the outer peripheral surface of the second coupling end 62. As a result, the radius of the second coupling end 62 of the rotary output component 60 is increased. During the operation of the rear wheel steering system 200 provided in this application, the position of the force of transmission between the various components is relatively far away from the axis of the rotary output component 60 along the radial direction of the rotary output component 60, thereby generating a larger transmitted torque and improving the load-bearing capacity of the rear wheel steering system 200.

[0148] Understandably, given a fixed volume of the rear wheel steering unit 200, if the driving force output by the steering motor 10 is the same, the rear wheel steering unit 200 provided in this application has a larger lever arm. This results in a relatively larger torque output by the rotary input component 50 during the synchronous rotation of the rotary output component 60, thus improving transmission efficiency. Furthermore, when the locking force output by multiple pairs of rolling elements 70 is the same when locking the rotary output component 60, the rear wheel steering unit 200 provided in this application has a larger lever arm. This results in a relatively larger torque provided by the multiple pairs of rolling elements 70 during the locking of the rotary output component 60, further improving transmission efficiency. In other words, the rear wheel steering unit 200 provided in this application, with a fixed volume, improves torque carrying capacity.

[0149] Conversely, provided that the rear wheel steering system 200 meets the torque required to drive or lock the tie rod 30 along its own axial displacement, the rear wheel steering system 200 provided in this application has a larger lever arm. Therefore, if the tie rod 30 is driven or locked to move the same distance along its own axial direction, the radial dimension required by the rear wheel steering system 200 along the rotary output member 60 is smaller. As a result, the overall volume of the rear wheel steering system 200 provided in this application can be relatively reduced while ensuring reliable operation, thereby saving interior space of the vehicle 1000.

[0150] Please refer to Figures 16 to 18. Figure 16 is a structural schematic diagram of the rear wheel steering system 200 provided in one embodiment of this application; Figure 17 is a structural schematic diagram of the rear wheel steering system 200 provided in one embodiment of this application; and Figure 18 is a cross-sectional structural schematic diagram of the rear wheel steering system 200 provided in one embodiment of this application.

[0151] In one embodiment, each axial protrusion 53 includes a radial groove. For ease of description, the radial groove of each axial protrusion 53 will be defined hereafter as a first radial groove 54. Each first radial groove 54 is recessed radially from the axis of the rotary output member 60 toward the outer edge of the rotary output member 60. Each axial protrusion 53 is used to accommodate the included angle formed by two adjacent side surfaces 63 through a first radial groove 54 to radially engage with a rotary output member 60. That is, each axial protrusion 53 is radially nested outside the included angle formed by two adjacent side surfaces 63 through a first radial groove 54 to engage with the rotary output member 60.

[0152] Alternatively, it can be understood that two adjacent side surfaces 63 in the second coupling end 62 form an included angle, and each included angle is used to embed into a first radial groove 54 along the radial direction of the rotary output component 60. Thus, during the rotation of the rotary input component 50, each axial protrusion 53 rotates about the axis of the rotary output component 60 and abuts against one of the two adjacent side surfaces 63 through one of the groove walls of the first radial groove 54, thereby driving the rotary output component 60 to rotate synchronously.

[0153] For ease of explanation, this application will subsequently define two adjacent sides 63 as the first side 631 and the second side 632, and the two groove walls of the first radial groove 54 as the first groove wall 541 and the second groove wall 542. In one embodiment, the first side 631 and the second side 632 are arranged in a clockwise direction, and the first groove wall 541 and the second groove wall 542 are also arranged in a clockwise direction.

[0154] When the rotary input component 50 rotates clockwise, multiple axial protrusions 53 rotate clockwise around the axis of the rotary output component 60. The first groove wall 541 of each axial protrusion 53 abuts against a first side surface 631, and the first groove walls 541 of the multiple axial protrusions 53 abut against a first side surface 631 respectively. Thus, the multiple axial protrusions 53 work together to drive the rotary output component 60 to rotate synchronously in the clockwise direction. When the rotary input component 50 rotates counterclockwise, multiple axial protrusions 53 rotate counterclockwise around the axis of the rotary output component 60. The second groove wall 542 of each axial protrusion 53 abuts against a second side surface 632, and the second groove walls 542 of the multiple axial protrusions 53 abut against a second side surface 632 respectively. Thus, the multiple axial protrusions 53 work together to drive the rotary output component 60 to rotate synchronously in the counterclockwise direction.

[0155] In one embodiment, along the circumference of the rotary output member 60, a gap is left between the first radial groove 54 of the axial protrusion 53 and the included angle formed by the two adjacent side surfaces 63. That is, a gap is left between the first groove wall 541 and the first side surface 631 and / or between the second groove wall 542 and the second side surface 632. The first coupling end 52 of the rotary input member 50 and the second coupling end 62 of the rotary output member 60 are decoupled in the initial state. This accommodates the system errors of the rear wheel steering system 200 provided in this application, avoids frequent contact between the rotary output member 60 and the rotary input member 50 when the rear wheel 1002 of the vehicle 1000 is subjected to an undesirable lateral force that drives the tie rod 30 to rotate in the opposite direction, and prevents the rotary input member 50 from being driven and releasing the locking state of the rolling element 70 on the rotary output member 60.

[0156] When the steering motor 10 outputs driving force to change the steering of the rear wheel 1002 in this application, the motor shaft 11 of the steering motor 10 rotates to drive the rotary input component 50 to rotate, thereby causing the axial protrusion 53 to rotate. When the rotation angle of the groove wall of the axial protrusion 53 crosses the gap between a groove wall located behind the rotation direction and an adjacent side 63, the groove wall abuts against the side 63, and the first coupling end 52 of the rotary input component 50 couples with the second coupling end 62 of the rotary output component 60, thereby causing the rotary output component 60 to rotate together to drive the axial displacement of the tie rod 30 and cause the rear wheel 1002 to deflect to achieve steering.

[0157] In one embodiment, the included angle between the two walls of the first radial groove 54 is less than or equal to the included angle formed by two adjacent side surfaces 63. For ease of explanation, the included angle between the two walls of the first radial groove 54 is defined as α1, and the included angle formed by two adjacent side surfaces 63 is defined as β1. That is, the included angle α1 between the first groove wall 541 and the second groove wall 542 is less than or equal to the included angle β1 formed by the first side surface 631 and the second side surface 632.

[0158] Based on the axial direction of the rotary output component 60, a gap is left between the first radial groove 54 of the axial protrusion 53 and the two adjacent side surfaces 63, so that the groove wall of the first radial groove 54 of each axial protrusion 53 needs to rotate with the rotary input component 50 by a certain angle before it abuts against one of the two adjacent side surfaces 63. In this embodiment of the application, by setting the angle α1 between the first groove wall 541 and the second groove wall 542 to be less than or equal to the angle β1 formed by the first side surface 631 and the second side surface 632, the contact area when the groove wall of the first radial groove 54 abuts against one of the two adjacent side surfaces 63 can be increased, thereby improving the circumferential force conditions of the rotary input component 50 and the rotary output component 60 and enhancing the torque bearing capacity of the rear wheel steering gear 200 provided in this application.

[0159] In one embodiment, the two groove walls of the first radial groove 54 in each axial protrusion 53 are symmetrically arranged along the radius axis of the rotary output member 60. That is, the first groove wall 541 and the second groove wall 542 are symmetrically arranged about one radius of the rotary output member 60. Along the circumference of the rotary output member 60, the inclination angle and offset distance of the first groove wall 541 and the second groove wall 542 of each first radial groove 54 relative to the radius of the rotary output member 60 are equal. The contact angle and contact area of ​​each first radial groove 54 when the first groove wall 541 pushes the first side surface 631 when the rotary input member 50 rotates clockwise are the same as the contact angle and contact area of ​​each first radial groove 54 when the second groove wall 542 pushes the second side surface 632 when the rotary input member 50 rotates counterclockwise. This helps to maintain the consistency of the torque output by the steering motor 10 in both forward and reverse rotation, and simplifies the control logic of the steering motor 10.

[0160] In one embodiment, the included angle formed by two adjacent sides 63 of the second coupling end 62 is symmetrically arranged along the radial axis of the rotary output member 60. That is, the first side 631 and the second side 632 are symmetrically arranged about a radius of the rotary output member 60. Along the circumference of the rotary output member 60, the tilt angle and offset distance of the first side 631 and the second side 632 relative to the radius of the rotary output member 60 are equal. The contact angle and contact area between each first side 631 and the first groove wall 541 when receiving the clockwise push of the first radial groove 54 are the same as the contact angle and contact area between each second side 632 and the second groove wall 542 when receiving the counterclockwise push of the first radial groove 54. This helps to maintain the consistency of the torque received by the rotary output member 60 when it rotates forward and backward with the steering motor 10, thereby ensuring the consistency of the torque transmitted to the tie rod 30 of the rear wheel 1002 and facilitating the control of the rotation angle of the rear wheel 1002.

[0161] In one embodiment, the two groove walls of the first radial groove 54 in each axial protrusion 53 are symmetrically arranged along the radial axis of the rotary output member 60, and the included angle formed by the two adjacent side surfaces 63 of the second coupling end 62 is symmetrically arranged along the radial axis of the rotary output member 60. That is, the first side surface 631 and the second side surface 632, the first groove wall 541 and the second groove wall 542 are respectively symmetrically arranged about one radius of the rotary output member 60. This is beneficial for maintaining the consistency of the torque output by the steering motor 10 when it rotates forward and backward, simplifying the control logic of the steering motor 10, and also for maintaining the consistency of the torque received by the rotary output member 60 when the steering motor 10 rotates forward and backward, thereby ensuring the consistency of the torque transmitted to the tie rod 30 of the rear wheel 1002 and facilitating the control of the rotation angle of the rear wheel 1002.

[0162] Please refer to Figures 19 to 21. Figure 19 is a structural schematic diagram of the rear wheel steering system 200 provided in one embodiment of this application; Figure 20 is a structural schematic diagram of the rear wheel steering system 200 provided in one embodiment of this application; and Figure 21 is a cross-sectional structural schematic diagram of the rear wheel steering system 200 provided in one embodiment of this application.

[0163] In one embodiment, each axial protrusion 53 includes a radial protrusion 55 extending radially from the outer edge of the rotary output member 60 toward its axis. A second radial groove is included between adjacent sides 63; for ease of description, this application will subsequently define the radial groove between adjacent sides 63 as a second radial groove 64. Each axial protrusion 53 is used to radially engage with the rotary output member 60 by embedding a radial protrusion 55 into a second radial groove 64. Alternatively, it can be understood that the rotary output member 60 is radially nested outside a radial protrusion 55 via each second radial groove 64 to engage with the rotary input member 50. Thus, during rotation of the rotary input member 50, each axial protrusion 53 abuts against a groove wall of the second radial groove 64 through a sidewall of the radial protrusion 55 to drive the rotary output member 60 to rotate synchronously.

[0164] For ease of explanation, the two sidewalls of the radial protrusion 55 will be defined as the first sidewall 551 and the second sidewall 552, respectively, and the two groove walls of the second radial groove 64 will be defined as the third groove wall 641 and the fourth groove wall 642, respectively. In one embodiment, the first sidewall 551 and the second sidewall 552 are arranged in a clockwise direction, and the third groove wall 641 and the fourth groove wall 642 are arranged in a clockwise direction.

[0165] When the rotary input component 50 rotates clockwise, the multiple axial protrusions 53 drive the radial protrusions 55 to rotate clockwise around the axis of the rotary output component 60. The second sidewall 552 of each radial protrusion 55 abuts against a fourth groove wall 642, and the second sidewalls 552 of the multiple radial protrusions 55 abut against a fourth groove wall 642 respectively. Thus, the multiple radial protrusions 55 work together to drive the rotary output component 60 to rotate synchronously in the clockwise direction. When the rotary input component 50 rotates counterclockwise, the multiple axial protrusions 53 drive the radial protrusions 55 to rotate counterclockwise around the axis of the rotary output component 60. The first sidewall 551 of each radial protrusion 55 abuts against a third groove wall 641, and the second sidewalls 552 of the multiple radial protrusions 55 abut against a third groove wall 641 respectively. Thus, the multiple radial protrusions 55 work together to drive the rotary output component 60 to rotate synchronously in the counterclockwise direction.

[0166] In one embodiment, along the circumference of the rotary output member 60, a gap exists between the radial protrusion 55 of the axial protrusion 53 and the groove wall of the second radial groove 64. That is, a gap exists between the first sidewall 551 and the third groove wall 641 and / or between the second sidewall 552 and the fourth groove wall 642. The first coupling end 52 of the rotary input member 50 and the second coupling end 62 of the rotary output member 60 are decoupled in the initial state. This accommodates the system errors of the rear wheel steering system 200 provided in this application, avoids frequent contact between the rotary output member 60 and the rotary input member 50 when the rear wheel 1002 of the vehicle 1000 is subjected to an undesirable lateral force that drives the tie rod 30 to rotate in the opposite direction, and prevents the rotary input member 50 from being driven and releasing the locking state of the rolling element 70 on the rotary output member 60.

[0167] When the steering motor 10 outputs driving force to change the steering of the rear wheel 1002, the motor shaft 11 of the steering motor 10 rotates to drive the rotary input component 50 to rotate, thereby causing the radial protrusion 55 of the axial protrusion 53 to rotate. When the angle of rotation of the radial protrusion 55 crosses the gap between a side wall located in front of the rotation direction and the groove wall of a second radial groove 64, the side wall abuts against the groove wall, and the first coupling end 52 of the rotary input component 50 couples with the second coupling end 62 of the rotary output component 60, thereby causing the rotary output component 60 to rotate together to drive the axial displacement of the tie rod 30 and cause the rear wheel 1002 to deflect to achieve steering.

[0168] In one embodiment, the included angle between the two sidewalls of the radial protrusion 55 is less than or equal to the included angle between the two groove walls of the second radial groove 64. For ease of explanation, the included angle between the two sidewalls of the radial protrusion 55 is defined as α2, and the included angle between the two groove walls of the second radial groove 64 is defined as β2. That is, the included angle α2 between the first sidewall 551 and the second sidewall 552 is less than or equal to the included angle β2 between the third groove wall 641 and the fourth groove wall 642.

[0169] Based on the axial direction of the rotary output member 60, a gap is left between the radial protrusion 55 of the axial protrusion 53 and the two groove walls of the second radial groove 64, so that the radial protrusion 55 of each axial protrusion 53 needs to rotate with the rotary input member 50 by a certain angle before it abuts against one of the groove walls of the second radial groove 64. In this embodiment of the application, by setting the included angle between the first side wall 551 and the second side wall 552 to be less than or equal to the included angle between the third groove wall 641 and the fourth groove wall 642, the contact area when the side wall of the radial protrusion 55 abuts against the groove wall of the second radial groove 64 can be increased, thereby improving the circumferential force conditions of the rotary input member 50 and the rotary output member 60 and enhancing the torque bearing capacity of the rear wheel steering gear 200 provided by this application.

[0170] In one embodiment, the two sidewalls of the radial protrusions 55 in each axial protrusion 53 are arranged symmetrically along the radius axis of the rotary output member 60. That is, the first sidewall 551 and the second sidewall 552 are symmetrically arranged about one radius of the rotary output member 60. Along the circumference of the rotary output member 60, the inclination angle and offset distance of the first sidewall 551 and the second sidewall 552 of each first radial protrusion 55 relative to the radius of the rotary output member 60 are equal. The contact angle and contact area of ​​each first radial protrusion 55 when the second sidewall 552 pushes the fourth groove wall 642 when the rotary input member 50 rotates clockwise are the same as the contact angle and contact area of ​​each first radial protrusion 55 when the first sidewall 551 pushes the third groove wall 641 when the rotary input member 50 rotates counterclockwise. This helps to maintain the consistency of the torque output by the steering motor 10 in both forward and reverse rotation, and simplifies the control logic of the steering motor 10.

[0171] In one embodiment, the two groove walls in the second radial groove 64 are arranged symmetrically along the radial axis of the rotating output member 60. That is, the third groove wall 641 and the fourth groove wall 642 are symmetrically arranged about one radius of the rotating output member 60. Along the circumference of the rotating output member 60, the inclination angle and offset distance of the third groove wall 641 and the fourth groove wall 642 of each second radial groove 64 relative to the radius of the rotating output member 60 are equal. The contact angle and contact area between the fourth groove wall 642 of each second radial groove 64 and the second side wall 552 when the radial protrusion 55 is pushed clockwise are the same as the contact angle and contact area between the third groove wall 641 of each second radial groove 64 and the first side wall 551 when the radial protrusion 55 is pushed counterclockwise. This helps to maintain the consistency of the torque received by the rotary output component 60 when the steering motor 10 rotates forward and backward, thereby ensuring the consistency of the torque transmitted to the tie rod 30 of the rear wheel 1002, which facilitates the control of the rotation angle of the rear wheel 1002.

[0172] In one embodiment, the two sidewalls of the radial protrusion 55 in each axial protrusion 53 are symmetrically arranged along the radial axis of the rotary output member 60, and the two groove walls in the second radial groove 64 are symmetrically arranged along the radial axis of the rotary output member 60. That is, the first sidewall 551 and the second sidewall 552, the third groove wall 641 and the fourth groove wall 642 are respectively symmetrically arranged about the radius of the rotary output member 60. This is beneficial for maintaining the consistency of the torque output by the steering motor 10 when it rotates forward and backward, simplifying the control logic of the steering motor 10, and also for maintaining the consistency of the torque received by the rotary output member 60 when the steering motor 10 rotates forward and backward, thereby ensuring the consistency of the torque transmitted to the tie rod 30 of the rear wheel 1002 and facilitating the control of the rotation angle of the rear wheel 1002.

[0173] Please refer to Figures 22 and 23 for reference. Figure 22 is a partial structural schematic diagram of a rear wheel steering system 200 provided in one embodiment of this application; Figure 23 is a partial structural schematic diagram of a rear wheel steering system 200 provided in one embodiment of this application.

[0174] In one embodiment, along the circumference of the rotary output member 60, each axial protrusion 53 includes a pair of circumferential sidewalls 56. Two of the pair of circumferential sidewalls 56 are respectively directed toward two pairs of rolling elements 70 arranged on the axial protrusion 53, and each axial protrusion 53 is used to drive two of the rolling elements 70 in the pair to approach each other via a circumferential sidewall 56 during rotation of a rotary input member 50.

[0175] For ease of explanation, the two pairs of rolling elements 70 located on either side of an axial protrusion 53 along the circumference of the rotating output member 60 are defined as the first pair of rolling elements 71 and the second pair of rolling elements 72, respectively. Similarly, the two circumferential sidewalls 56 of a pair of circumferential sidewalls 56 of each axial protrusion 53 are defined as the first circumferential sidewall 561 and the second circumferential sidewall 562, respectively. In one embodiment, the first pair of rolling elements 71, the first circumferential sidewall 561 of the axial protrusion 53, the second circumferential sidewall 562 of the axial protrusion 53, and the second pair of rolling elements 72 are arranged sequentially in a clockwise direction. For ease of explanation, the two rolling elements 70 in the first pair of rolling elements 71 are defined as the first rolling element 711 and the second rolling element 712, respectively, and the two rolling elements 70 in the second pair of rolling elements 72 are defined as the third rolling element 721 and the fourth rolling element 722, respectively. In one embodiment, the first rolling element 711, the second rolling element 712, the first circumferential sidewall 561, the second circumferential sidewall 562, the third rolling element 721, and the fourth rolling element 722 are arranged in a clockwise direction.

[0176] When the rotary input member 50 rotates clockwise, causing the axial protrusions 53 to rotate together, each axial protrusion 53 abuts against the third rolling member 721 via the second circumferential sidewall 562, and pushes the third rolling member 721 closer to the fourth rolling member 722, thereby releasing the locking state of the second pair of rolling members 72 on the rotary output member 60. When the rotary input member 50 rotates counterclockwise, causing the axial protrusions 53 to rotate together, each axial protrusion 53 abuts against the second rolling member 712 via the first circumferential sidewall 561, and pushes the second rolling member 712 closer to the first rolling member 711, thereby releasing the locking state of the first pair of rolling members 71 on the rotary output member 60.

[0177] In one embodiment, along the circumference of the rotating output member 60, the sum of the gaps between a pair of circumferential sidewalls 56 of each axial protrusion 53 and two pairs of rolling elements 70 arranged on both sides of the axial protrusion 53 is less than the circumferential gap at the radial engagement point between the axial protrusion 53 and the rotating output member 60.

[0178] In the embodiment corresponding to the axial protrusion 53 including the first radial groove 54, along the circumference of the rotating output member 60, the sum of the gap between the first circumferential sidewall 561 and the second rolling member 712 and the gap between the second circumferential sidewall 562 and the third rolling member 721 is less than the circumferential gap between the first groove wall 541 and the second groove wall 542. Alternatively, it can be understood that the difference between the arc length between the second rolling member 712 and the third rolling member 721 and the arc length between the first circumferential sidewall 561 and the second circumferential sidewall 562 is less than the difference between the arc length between the first groove wall 541 and the second groove wall 542 and the arc length between the first side surface 631 and the second side surface 632.

[0179] In the embodiment corresponding to the axial protrusion 53 including the radial protrusion 55, along the circumference of the rotating output member 60, the sum of the gap between the first circumferential sidewall 561 and the second rolling member 712 and the gap between the second circumferential sidewall 562 and the third rolling member 721 is less than the circumferential gap between the third groove wall 641 and the fourth groove wall 642. Alternatively, it can be understood that the difference between the arc length between the second rolling member 712 and the third rolling member 721 and the arc length between the first circumferential sidewall 561 and the second circumferential sidewall 562 is less than the difference between the arc length between the third groove wall 641 and the fourth groove wall 642 and the arc length between the first sidewall 551 and the second sidewall 552.

[0180] This ensures that during the rotation of the rotary input component 50, the contact between the circumferential sidewall 56 and the rolling element 70 occurs before the axial protrusion 53 drives the rotary output component 60 to rotate. That is, the axial protrusion 53 first pushes one of the rolling elements 70 close to the other to release the locking state of the rolling elements 70 on the rotary output component 60, and then drives the rotary output component 60 to rotate synchronously, avoiding potential jamming when the axial protrusion 53 first contacts the rotary output component 60 before pushing the rolling elements 70.

[0181] In one embodiment, the two circumferential sidewalls 56 of each axial protrusion 53 are arranged symmetrically along the radius axis of the rotary output member 60. That is, the first circumferential sidewall 561 and the second circumferential sidewall 562 are symmetrically arranged about one radius of the rotary output member 60. Along the circumference of the rotary output member 60, the inclination angle and offset distance of the pair of circumferential sidewalls 56 of each axial protrusion 53 relative to the radius of the rotary output member 60 are equal. When the rotary input member 50 rotates clockwise, the contact angle and contact distance of the second circumferential sidewall 562 pushing the third rolling member 721 are the same as the contact angle and contact distance of the first circumferential sidewall 561 pushing the second rolling member 712 when the rotary input member 50 rotates counterclockwise. This facilitates the synchronization of the rotation of the rotary output member 60 when the steering motor 10 rotates forward and reverse, simplifying the control logic of the steering motor 10.

[0182] In one embodiment, each axial protrusion 53 includes a first radial groove 54. One of a pair of circumferential sidewalls 56 is connected to the other groove wall through one wall of the first radial groove 54, and the one circumferential sidewall 56 is parallel to the other groove wall. That is, the first circumferential sidewall 561 is connected to the second groove wall 542 through the first groove wall 541, and the second circumferential sidewall 562 is connected to the first groove wall 541 through the second groove wall 542. Furthermore, the first circumferential sidewall 561 is parallel to the second groove wall 542, and the second circumferential sidewall 562 is parallel to the first groove wall 541.

[0183] As each axial protrusion 53 rotates clockwise with the rotary input component 50, it abuts against the third rolling element 721 and the first side surface 631 respectively via the second circumferential side wall 562 and the first groove wall 541. Because the second circumferential side wall 562 is parallel to the first groove wall 541, it is convenient to control the timing of each axial protrusion 53 pushing the third rolling element 721 and the first side surface 631, avoiding jamming caused by the first groove wall 541 contacting the first side surface 631 before the second circumferential side wall 562 contacting the third rolling element 721.

[0184] When each axial protrusion 53 rotates counterclockwise with the rotary input component 50, it abuts against the second rolling element 712 and the second side surface 632 through the first circumferential side wall 561 and the second groove wall 542, respectively. Since the first circumferential side wall 561 and the second groove wall 542 are parallel, it is convenient to control the timing of each axial protrusion 53 pushing the second rolling element 712 and the second side surface 632, avoiding jamming caused by the second groove wall 542 contacting the second side surface 632 before the first circumferential side wall 561 contacts the second rolling element 712.

[0185] Please refer to Figures 24 and 25, where Figure 24 is a partial structural schematic diagram of a rear wheel steering system 200 provided in one embodiment of this application; Figure 25 is a partial structural schematic diagram of a rear wheel steering system 200 provided in one embodiment of this application.

[0186] In one embodiment, each axial protrusion 53 includes a radial protrusion 55. Along the circumference of the rotary output member 60, one of a pair of circumferential sidewalls 56 and one sidewall of the radial protrusion 55 are located on the same side of the axial protrusion 53, and the other circumferential sidewall 56 and the other sidewall of the radial protrusion 55 are located on the opposite side of the axial protrusion 53. One circumferential sidewall 56 is parallel to one sidewall, and the other circumferential sidewall 56 is parallel to the other sidewall. That is, along the circumference of the rotary output member 60, a first circumferential sidewall 561 and a first sidewall 551 are located on the same side of the axial protrusion 53, and a second circumferential sidewall 562 and a second sidewall 552 are located on the opposite side of the axial protrusion 53. Furthermore, the first circumferential sidewall 561 is parallel to the first sidewall 551, and the second circumferential sidewall 562 is parallel to the second sidewall 552.

[0187] As each axial protrusion 53 rotates clockwise with the rotary input component 50, it abuts against the third rolling element 721 and the fourth groove wall 642 via the second circumferential sidewall 562 and the second sidewall 552, respectively. Because the second circumferential sidewall 562 is parallel to the second sidewall 552, it is convenient to control the timing of each axial protrusion 53 pushing the third rolling element 721 and the fourth groove wall 642, thus avoiding jamming caused by the second sidewall 552 contacting the fourth groove wall 642 before the second circumferential sidewall 562 contacts the third rolling element 721.

[0188] When each axial protrusion 53 rotates counterclockwise with the rotary input component 50, it abuts against the second rolling element 712 and the third groove wall 641 through the first circumferential sidewall 561 and the first sidewall 551, respectively. Because the first circumferential sidewall 561 is parallel to the first sidewall 551, it is convenient to control the timing of each axial protrusion 53 pushing the second rolling element 712 and the third groove wall 641, avoiding jamming caused by the first sidewall 551 contacting the third groove wall 641 before the first circumferential sidewall 561 contacting the second rolling element 712.

[0189] In one embodiment, the two sidewalls of the radial protrusion 55 in each axial protrusion 53 are respectively formed by two circumferential sidewalls 56. That is, the first circumferential sidewall 561 and the second circumferential sidewall 562 extend radially toward the axis of the rotary output member 60. The portion of the first circumferential sidewall 561 embedded in the second radial groove 64 along the radial direction of the rotary output member 60 forms the first sidewall 551 of the radial protrusion 55, and the portion of the second circumferential sidewall 562 embedded in the second radial groove 64 along the radial direction of the rotary output member 60 forms the second sidewall 552 of the radial protrusion 55. In other words, in each axial protrusion 53, the first sidewall 551 and the first circumferential sidewall 561 are coplanar, and the second sidewall 552 and the second circumferential sidewall 562 are coplanar. This structural design simplifies the shape of each axial protrusion 53 and facilitates the machining of the rotary input member 50.

[0190] Please refer to Figure 26 for a partial structural schematic diagram of a rear wheel steering system 200 provided in one embodiment of this application.

[0191] In one embodiment, two adjacent axial protrusions 53 include two opposing circumferential sidewalls 56, which are accommodated in the gap between the same side 63 and the inner wall of the housing 40 and arranged on both sides of a pair of rolling elements 70. The two opposing circumferential sidewalls 56 are respectively perpendicular to the direction in which the two rolling elements 70 are arranged.

[0192] Along the circumference of the rotating output member 60, two pairs of rolling elements 70 are arranged on both sides of the same axial protrusion 53, meaning the two axial protrusions 53 are arranged on both sides of the same pair of rolling elements 70. That is, multiple pairs of rolling elements 70 and multiple axial protrusions 53 alternately surround the outer circumferential surface of the rotating output member 60. Each of two adjacent axial protrusions 53 includes a circumferential sidewall 56 acting on the same pair of rolling elements 70. Along the arrangement direction of the two rolling elements 70 in a pair, the circumferential sidewalls 56 of the two axial protrusions 53 face each other. The two facing circumferential sidewalls 56 are perpendicular to the arrangement direction of the two rolling elements 70 in a pair.

[0193] For ease of explanation, two adjacent axial protrusions 53 are defined as a first axial protrusion 53a and a second axial protrusion 53b, respectively. In one embodiment, the first axial protrusion 53a and the second axial protrusion 53b are arranged in a clockwise direction. The second circumferential sidewall 562 of the first axial protrusion 53a is disposed opposite to the first circumferential sidewall 561 of the second axial protrusion 53b. For ease of explanation, the circumferential sidewalls 56 disposed opposite to each other in the first axial protrusion 53a and the second axial protrusion 53b are defined as a third circumferential sidewall 563 and a fourth circumferential sidewall 564, respectively. The third circumferential sidewall 563 is the second circumferential sidewall 562 of the first axial protrusion 53a, and the fourth circumferential sidewall 564 is the first circumferential sidewall 561 of the second axial protrusion 53b. The third circumferential sidewall 563 and the fourth circumferential sidewall 564 are accommodated in the gap between the second side surface 632 and the inner wall of the housing 40. The third circumferential sidewall 563 and the fourth circumferential sidewall 564 are located on both sides of the second pair of rolling elements 72. Furthermore, the third circumferential sidewall 563 and the fourth circumferential sidewall 564 are perpendicular to the arrangement direction of the two rolling elements 70 in the second pair of rolling elements 72. That is, both the third circumferential sidewall 563 and the fourth circumferential sidewall 564 extend in a direction perpendicular to the arrangement direction of the two rolling elements 70 in the second pair of rolling elements 72.

[0194] In this embodiment, by limiting the extension direction of the two circumferential sidewalls 56 acting on the same pair of rolling elements 70 to be perpendicular to the arrangement direction of the two rolling elements 70 in the pair, the spacing distance between the two circumferential sidewalls 56 and the two rolling elements 70 in the pair can be controlled, thereby controlling the timing at which each circumferential sidewall 56 contacts and pushes a rolling element 70. This facilitates the simultaneous release of the locking state of multiple pairs of rolling elements 70 on the rotary output element 60 when each axial protrusion 53 rotates with the rotary input element 50.

[0195] In one embodiment, along the circumference of the rotary output member 60, during the process of the rotary input member 50 stopping its rotation, the distance between two opposing circumferential sidewalls 56 is greater than the width of a pair of rolling elements 70 between the opposing circumferential sidewalls 56. That is, the distance between the third circumferential sidewall 563 and the fourth circumferential sidewall 564 is greater than the sum of the diameter of the third rolling element 721, the diameter of the fourth rolling element 722, and the distance between the third rolling element 721 and the fourth rolling element 722 in the second pair of rolling elements 72.

[0196] In this embodiment, along the circumference of the rotating output member 60, the distance between two opposing circumferential sidewalls 56 is greater than the sum of the distance between a pair of rolling elements 70 and the diameters of the two rolling elements 70, meaning that the two opposing circumferential sidewalls 56 are spaced apart from the pair of rolling elements 70. This avoids either of the two opposing circumferential sidewalls 56 from contacting either rolling element 70 and affecting the locking effect of the pair of rolling elements 70 on one of the side surfaces 63.

[0197] In one embodiment, along a direction perpendicular to the arrangement of the two rolling elements 70, the height of the two opposing circumferential sidewalls 56 is greater than or equal to the radius of each rolling element 70 in the pair. That is, along a direction perpendicular to the arrangement of the two rolling elements 70, the height of the third circumferential sidewall 563 and the fourth circumferential sidewall 564 is greater than or equal to the radius of each rolling element 70 in the pair.

[0198] In this embodiment, the height of each circumferential sidewall 56 is set to be at least greater than the radius of the rolling element 70, thereby ensuring that each axial protrusion 53 abuts against the middle of the rolling element 70 during the rotation of the rotary input element 50, which facilitates pushing one of the rolling elements 70 in a pair of rolling elements 70 toward the other rolling element 70, and at the same time facilitates controlling the timing of each circumferential sidewall 56 contacting the rolling element 70.

[0199] In one embodiment, two opposing circumferential sidewalls 56 are arranged symmetrically along the radial axis of the rotary output member 60. That is, the third circumferential sidewall 563 and the fourth circumferential sidewall 564 are symmetrically arranged about one radius of the rotary output member 60. The distances between the third circumferential sidewall 563 and the fourth circumferential sidewall 564 and the radius of the rotary output member 60 are equal. In this embodiment, setting the distances between the two opposing circumferential sidewalls 56 and the radius of the rotary output member 60 is equal facilitates controlling the spacing between the two opposing circumferential sidewalls 56 and the two rolling elements 70 of a pair. This is beneficial because it ensures that each axial protrusion 53 rotates at the same angle as the rotary input member 50 rotates clockwise and counterclockwise to release the locking state of the multiple pairs of rolling elements 70 on the rotary output member 60. This means that the timing at which each axial protrusion 53 contacts multiple pairs of rolling elements 70 on its circumferential sidewall 56 to release the locking state of the rotary output element 60 when the rotary input element 50 rotates clockwise is the same as the timing at which each axial protrusion 53 contacts multiple pairs of rolling elements 70 on its circumferential sidewall 56 to release the locking state of the rotary output element 60 when the rotary input element 50 rotates counterclockwise, thereby simplifying the control logic of the steering motor 10.

[0200] In one embodiment, each side 63 is a plane. By making each side 63 in the second coupling end 62 of the rotary output member 60 a plane, the structure of the rotary output member 60 is simplified and the machining of each side 63 is facilitated.

[0201] In one embodiment, the various side surfaces 63 are evenly distributed along the circumference of the rotary output member 60. Thus, when the rotary input member 50 is not rotating and the pairs of rolling elements 70 lock the rotary output member 60, the locking forces of the respective pairs of rolling elements 70 on each side surface 63 are relatively evenly distributed around the outer circumference of the rotary output member 60. This improves the stress condition of the second coupling end 62 of the rotary output member 60 and prevents deformation of the second coupling end 62 due to uneven stress.

[0202] In one embodiment, each side 63 is symmetrical about the radius axis of the rotary output member 60. That is, each side 63 is symmetrical about one radius of the rotary output member 60. This arrangement facilitates each side 63 receiving the supporting force of a pair of rolling elements 70 to limit the rotation of the rotary output member 60. Simultaneously, because each side 63 is symmetrical about the radius axis of the rotary output member 60, the supporting forces of the two rolling elements 70 in each pair acting on one side 63 are relatively balanced. Therefore, the locking force of the rear wheel steering system 200 on the tie rod 30 of the rear wheel 1002 tends to be consistent clockwise and counterclockwise.

[0203] In one embodiment, two adjacent side surfaces 63 are arranged symmetrically along the radial axis of the rotary output member 60. That is, the first side surface 631 and the second side surface 632 are symmetrically arranged about one radius of the rotary output member 60. This ensures that the first side surface 631 and the second side surface 632 receive consistent torque when the motor rotates forward and backward after being radially engaged with the axial protrusion 53, thereby ensuring consistent torque transmitted to the tie rod 30 of the rear wheel 1002 and facilitating control of the rotation angle of the rear wheel 1002.

[0204] In one embodiment, the second coupling end 62 of the rotating output member 60 is square. That is, the orthographic projection of the second coupling end 62 in the radial plane of the rotating output member 60 is a square.

[0205] In one embodiment, the second coupling end 62 of the rotating output member 60 is an equilateral triangle. That is, the orthographic projection of the second coupling end 62 in the radial plane of the rotating output member 60 is an equilateral triangle.

[0206] In the two embodiments described above, the second coupling end 62 of the rotary output member 60 has fewer side surfaces 63, and each side surface 63 has a relatively large area, thus possessing better load-bearing capacity. When the rotary output member 60 is not rotating, each side surface 63 can receive greater pressure from multiple pairs of rolling elements 70 to limit the rotation of the rotary output member 60.

[0207] In one embodiment, each elastic component 80 is arranged circumferentially between two of a pair of rolling elements 70 along the rotation output member 60. That is, along the circumferential direction of the rotation output member 60, one rolling element 70, the elastic component 80, and the other rolling element 70 are arranged sequentially. Along the arrangement direction of the two rolling elements 70 in the pair, both ends of the elastic component 80 can abut against the two rolling elements 70 respectively to drive the two rolling elements 70 away from each other. Perpendicular to the arrangement direction of the two rolling elements 70 in the pair, the elastic component 80 is accommodated in the gap between a side surface 63 and the inner wall of the housing 40. By accommodating the elastic component 80 together with the pair of rolling elements 70 in the gap between the side surface 63 and the inner wall of the housing 40, it is not necessary to provide a separate accommodating space for the elastic component 80, thereby reducing the overall volume of the rear wheel steering system 200 provided in this application.

[0208] Please refer to Figures 27 to 29, where Figure 27 is a partial structural schematic diagram of the rear wheel steering system 200 provided in one embodiment of this application; Figure 28 is a partial structural schematic diagram of the rear wheel steering system 200 provided in one embodiment of this application; and Figure 29 is a partial structural schematic diagram of the rear wheel steering system 200 provided in one embodiment of this application.

[0209] In one embodiment, each side surface 63 includes a fixing groove 65, the opening of which faces the inner wall of the housing 40 radially along the rotary output member 60. Each fixing groove 65 is used to fix an elastic component 80. The elastic components 80 are arranged circumferentially between two of a pair of rolling members 70 along the rotary output member 60. The elastic components 80 are positioned by being embedded in the fixing grooves 65 of the side surface 63 radially along the rotary output member 60. The fixing grooves 65 can also be used to limit the orientation of the elastic components 80 between the two rolling members 70, preventing deformation or displacement of the elastic components 80 from affecting the relative displacement between the two rolling members 70.

[0210] In one embodiment, each elastic component 80 is a U-shaped spring, which includes two spring pieces 81 and a U-shaped connecting end 82. In another embodiment, along the radial direction of the rotating output member 60, the inner wall of the housing 40, the two spring pieces 81, and the U-shaped connecting end 82 are arranged sequentially. The U-shaped connecting end 82 is used to embed into the fixing groove 65 of the side surface 63 and to connect the two spring pieces 81. The two spring pieces 81 extend from the U-shaped connecting end 82 toward the inner wall of the housing 40 along a direction perpendicular to the arrangement of the two rolling elements 70 in the pair. Along the circumference of the rotating output member 60, the two spring pieces 81 are located between the two rolling elements 70 of the pair, and are spaced apart along the arrangement direction of the two rolling elements 70. The two spring pieces 81 are respectively used to abut against the two rolling elements 70 in the pair.

[0211] Based on the small size, ease of installation and fixation, and resistance to deformation of the U-shaped spring, this application sets the elastic component 80 as a U-shaped spring, which can effectively drive the two rolling elements 70 away from each other. Each spring 81 of the U-shaped spring is used to abut against one rolling element 70. When one spring 81 is deformed by the compression of one rolling element 70, the shape of the other spring 81 remains relatively stable. When the rotary input component 50 rotates clockwise or counterclockwise with the steering motor 10, the two springs 81 deform alternately, which can improve the reliability of the elastic component 80 and extend its service life.

[0212] In one embodiment, the bending radius of the U-shaped connecting end 82 of the U-shaped spring is smaller than the spacing between the two spring pieces 81. The U-shaped connecting end 82 is used to embed into the fixing groove 65 of the side 63. By setting the bending radius of the U-shaped connecting end 82 to be smaller than the spacing between the two spring pieces 81, the size of the U-shaped connecting end 82 embedded in the side 63 is relatively large. The U-shaped spring can be better embedded in the fixing groove 65 of the side 63 and prevent it from falling out, thereby improving the reliability of the connection between the elastic component 80 and the side 63.

[0213] In one embodiment, the length of each spring piece 81 protruding from the side 63 is greater than the radius of the rolling element 70 that abuts against the spring piece 81. In another embodiment, each spring piece 81 includes a first segment 811 and a second segment 812 along its length. The first segment 811 extends into the fixing groove 65 of the side 63 to connect with the U-shaped connecting end 82 and abuts against the groove wall of the fixing groove 65 to limit the displacement of the U-shaped spring. The second segment 812 protrudes from the side 63 and extends between the two rolling elements 70 of a pair of rolling elements 70. The second segment 812 abuts against the rolling elements 70, and its length is greater than the radius of the rolling element 70.

[0214] In this embodiment of the application, by setting the length of each second segment 812 to exceed the radius of the rolling element 70, it can be ensured that each spring 81 can abut against the middle of the rolling element 70, so that the spring 81 can push the two rolling elements 70 away from each other.

[0215] In one embodiment, the housing 40 of the rear wheel steering gear 200 provided in this application includes an input-side housing 41 and an output-side housing 42 (as shown in FIG. 9). The input-side housing 41 and the output-side housing 42 are arranged adjacent to each other along the axial direction of the motor shaft 11 of the steering motor 10, and the output-side housing 42 is used to enclose the input-side housing 41. The input-side housing 41 is used to fix the outer ring 91 of the bearing 90, and the inner ring 92 of the bearing 90 is used to fix the first transmission end 51 of the rotating input member 50. The output-side housing 42 is used to fix the outer ring 91 of another bearing 90, and the inner ring 92 of the other bearing 90 is used to fix the second transmission end 61 of the rotating output member 60.

[0216] That is, in this application, the output-side housing 42 encloses the input-side housing 41 to form the housing 40 of the rear wheel steering gear 200. The rear wheel steering gear 200 provided in this application also includes two bearings 90, both of which are housed and fixed within the housing 40. One bearing 90 supports the rotary input component 50, and the other bearing 90 supports the rotary output component 60. This application uses two bearings 90 to support the rotary input component 50 and the rotary output component 60 respectively, ensuring that the rotary input component 50 and the rotary output component 60 rotate smoothly around the axis of the rear wheel steering gear 200.

[0217] In one embodiment, the output-side housing 42 includes a mounting surface with a plurality of bolt holes 421, each bolt hole 421 for passing through a bolt. The input-side housing 41 includes another mounting surface for securing the output-side housing 42, and the other mounting surface includes a plurality of bolt slots 411, each bolt slot 411 for securing and receiving a bolt 43 passing through a bolt hole 421.

[0218] Please refer to Figures 30 and 31 for reference. Figure 30 is a partial structural schematic diagram of the rear wheel steering system 200 provided in one embodiment of this application; Figure 31 is a partial structural schematic diagram of the rear wheel steering system 200 provided in one embodiment of this application.

[0219] In one embodiment, the inner wall of the housing 40 further includes a retaining ring 44. The axis of the retaining ring 44 coincides with the axis of the rotary output member 60. Along the radial direction of the rotary output member 60, the retaining ring 44 surrounds the periphery of the axial protrusion 53 and the rolling member 70. The retaining ring 44 engages with the side surface 63 of the second coupling end 62 to limit the radial displacement of the rolling member 70 along the rotary output member 60.

[0220] In one embodiment, the inner wall of the housing 40 includes a circumferential surface 45. During the process of a rotary input 50 stopping its rotation, each elastic component 80 is used to drive two of a pair of rolling elements 70 to abut against the circumferential surface 45 of the inner wall of the housing 40 and the same side surface 63 respectively to lock the rotation of a rotary output 60.

[0221] In this embodiment, the gaps between the circumferential surface 45 of the inner wall of the housing 40 and each side surface 63 are crescent-shaped. The gaps are larger in the middle and gradually decrease towards the sides along the radial dimension of the rotary output member 60. When the two rolling elements 70 move away from each other, each rolling element 70 abuts against the circumferential surface 45 and the side surface 63 of the inner wall of the housing 40, thus restricting the rotational movement of the rotary output member 60 in one direction of rotation. Two of the rolling elements 70 abut against the circumferential surface 45 and the same side surface 63 of the inner wall of the housing 40, thereby restricting the rotational movement of the rotary output member 60 in clockwise and counterclockwise directions of rotation. This rear-wheel steering system 200 thus forms the effect of two unidirectional clutches connected in series, reducing the overall size of the rear-wheel steering system 200 and saving interior space in the vehicle 1000.

[0222] In one embodiment, two of the rolling elements 70 are cylindrical, and the cylindrical central axis of each rolling element 70 is parallel to the axial direction of a rotating output element 60. The cylindrical diameters of the two rolling elements 70 are equal.

[0223] The cylindrical rolling elements 70 form larger contact surfaces with the side surface 63 and the inner wall of the housing 40, thereby improving the load-bearing capacity of the rear wheel steering system 200 of this application. The two rolling elements 70 have equal diameters, and the radii of the two rolling elements 70 moving away from each other are equal. The torques of the abutting forces exerted by the two rolling elements 70 on the side surface 63 are also relatively consistent. Therefore, during the process of the rotary input element 50 stopping rotation, the clockwise locking force and the counterclockwise locking force of the two rolling elements 70 on the rotary output element 60 are relatively consistent, which improves the reliability of the rear wheel steering system 200 of this application.

[0224] In one embodiment, the inner wall of the housing 40 includes a circumferential surface 45. Two of the rolling elements 70 in each pair are symmetrically arranged along one radial axis of the rotating output element 60, and adjacent pairs of rolling elements 70 are symmetrically arranged along another radial axis of the rotating output element 60. For ease of description, the axis of symmetry of two adjacent pairs of rolling elements 70 is defined as the first axis of symmetry, and the axis of symmetry of two of the rolling elements 70 in each pair is defined as the first axis of symmetry.

[0225] In one embodiment, two adjacent side surfaces 63 are symmetrically arranged about a first axis of symmetry along the circumference of the rotating output member 60. Each side surface 63 is arranged about a second axis of symmetry. Thus, the supporting forces of the two rolling elements 70 in each pair of rolling elements 70 acting on one side surface 63 are relatively balanced, and the locking force of the rear wheel steering gear 200 on the tie rod 30 of the rear wheel 1002 tends to be consistent in both clockwise and counterclockwise directions. Furthermore, the consistency of the torque received by the two adjacent side surfaces 63 after radial engagement with the axial protrusion 53 during forward and reverse rotation of the motor ensures consistent torque transmitted to the tie rod 30 of the rear wheel 1002, facilitating control of the rotation angle of the rear wheel 1002.

[0226] In one embodiment, two adjacent elastic components 80 are symmetrically arranged about a first axis of symmetry along the circumference of the rotary output component 60. Two spring tabs 81 and a U-shaped connecting end 82 in each elastic component 80 are symmetrically arranged about the first axis of symmetry. Thus, when the rotary input component 50 rotates clockwise or counterclockwise with the steering motor 10, the two spring tabs 81 of each elastic component 80 deform alternately, which can improve the reliability of the elastic components 80 and extend their service life.

[0227] In one embodiment, two opposing circumferential sidewalls 56 are symmetrically arranged about a second axis of symmetry. This facilitates that the timing at which each axial protrusion 53 contacts multiple pairs of rolling elements 70 to release the locking state of the rotary output element 60 when the circumferential sidewalls 56 contact the multiple pairs of rolling elements 70 when the axial protrusions 53 contact the multiple pairs of rolling elements 70 to release the locking state of the rotary output element 60 when the circumferential sidewalls 56 contact the multiple pairs of rolling elements 70 to release the locking state of the rotary output element 60 when the axial protrusions 53 contact the multiple pairs of rolling elements 70 to release the locking state of the rotary output element 60 when the circumferential sidewalls 56 contact the rotary input element 50 when the rotary input element 50 rotates counterclockwise, thereby simplifying the control logic of the steering motor 10.

[0228] In one embodiment, along the circumference of the rotary output member 60, two adjacent side surfaces 63 and two adjacent elastic components 80 are symmetrically arranged about a first axis of symmetry. The two spring tabs 81 and U-shaped connecting ends 82 in each side surface 63 and each elastic component 80 are symmetrically arranged about a second axis of symmetry. Thus, when the rotary input member 50 is not rotating, the supporting forces of the two rolling elements 70 in each pair of rolling elements 70 acting on one side surface 63 are relatively balanced, and the locking force of the rear wheel steering gear 200 on the tie rod 30 of the rear wheel 1002 tends to be consistent clockwise and counterclockwise. When the rotary input member 50 rotates, the timing of its clockwise and counterclockwise rotation with the steering motor 10 to release the rolling elements 70 from the locking state of the rotary output member 60 is the same, simplifying the control logic of the steering motor 10.

[0229] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the scope of protection of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A rear wheel steering system with locking function, characterized in that, The housing of the rear wheel steering system is used to accommodate a rotary input component, a rotary output component, multiple pairs of rolling elements, and multiple elastic components. The drive end of the rotary input component receives drive from the vehicle's steering motor. The coupling end of the rotary input component is used to drively connect to the coupling end of the rotary output component. The drive end of the rotary output component is used to drively connect to the tie rod of at least one rear wheel in the vehicle. The coupling end of the rotary input device includes a plurality of axial protrusions, which are spaced apart around the coupling end of the rotary output device, and the rotary output device and each of the axial protrusions are embedded in the radial direction of the rotary output device. The outer peripheral surface of the coupling end of the rotary output member includes multiple side surfaces. The gap between each side surface and the housing is used to accommodate a pair of rolling elements. Two pairs of rolling elements that are adjacent to each other along the circumference of the rotary output member are respectively arranged on both sides of an axial protrusion. Two rolling elements in each pair are spaced apart between two axial protrusions. Each of the elastic components is used to drive the two of the pair of rolling elements away from each other and lock the rotation of the rotary output element during the process of the rotary input element stopping rotation, and each of the axial protrusions is used to drive the pair of rolling elements closer to each other and drive the rotation of the rotary output element during the process of the rotary input element rotating.

2. The rear wheel steering system as described in claim 1, characterized in that, Each of the axial protrusions includes a radial groove, and each of the axial protrusions is used to receive the included angle formed by two adjacent sides through the radial groove so as to radially engage with one of the rotary output components; or... Each of the axial protrusions includes a radial protrusion, and between two adjacent sides is another radial groove, each of the axial protrusions being used to be radially engaged with the other radial groove via the radial protrusion.

3. The rear wheel steering system as described in claim 2, characterized in that, The included angle between the two walls of the radial groove is less than or equal to the included angle formed by the two side surfaces; or... The included angle between the two sidewalls of the radial protrusion is less than or equal to the included angle between the two groove walls in the other radial groove.

4. The rear wheel steering system as described in any one of claims 1-3, characterized in that, Along the circumference of the rotary output component, each of the axial protrusions includes a pair of circumferential sidewalls, two of the circumferential sidewalls being directed toward two pairs of rolling elements arranged on either side of the axial protrusion, and each axial protrusion being used to drive a pair of rolling elements toward each other via one of the circumferential sidewalls during the rotation of the rotary input component.

5. The rear wheel steering system as described in claim 4, characterized in that, Along the circumference of the rotary output component, the sum of the gaps between a pair of circumferential sidewalls of each axial protrusion and the two pairs of rolling elements arranged on both sides of the axial protrusion is less than the circumferential gap at the radial engagement point between the axial protrusion and the rotary output component.

6. The rear wheel steering system as described in claim 4 or 5, characterized in that, The two adjacent axial protrusions include two opposing circumferential sidewalls, which are accommodated in the gap between the same side and the inner wall of the housing and are arranged on both sides of the pair of rolling elements. The two opposing circumferential sidewalls are respectively perpendicular to the direction in which the two rolling elements are arranged in the pair of rolling elements.

7. The rear wheel steering system as described in claim 6, characterized in that, Along the circumference of the rotary output component, during the process of the rotary input component stopping rotation, the distance between the two opposite circumferential sidewalls is greater than the width of the pair of rolling elements between the two opposite circumferential sidewalls.

8. The rear wheel steering system as described in claim 6 or 7, characterized in that, Along a direction perpendicular to the arrangement of the two rolling elements in the pair, the height dimension of the two opposing circumferential sidewalls is greater than or equal to the radius of each of the rolling elements in the pair.

9. The rear wheel steering system as described in any one of claims 1-8, characterized in that, Each of the sides is a plane, and each side is symmetrical about the radius axis of the rotating output component. Adjacent sides are arranged symmetrically about the radius axis of the rotating output component.

10. The rear wheel steering system as described in any one of claims 1-9, characterized in that, Each of the sides includes a fixing groove, the opening of each fixing groove facing the inner wall of the housing along the radial direction of the rotary output member, each fixing groove being used to fix one of the elastic components, and each elastic component being arranged between two of the two rolling elements in a pair of rolling elements along the circumference of the rotary output member.

11. The rear wheel steering system as described in any one of claims 1-10, characterized in that, Each of the elastic components is a U-shaped spring, which includes two spring pieces and a U-shaped connecting end. The U-shaped connecting end is used to be embedded in the side and to connect the two spring pieces. The two spring pieces are used to abut against the two rolling elements of the pair of rolling elements respectively.

12. The rear wheel steering system as claimed in claim 11, characterized in that, The bending radius of the U-shaped connecting end of the U-shaped spring is less than the spacing between the two spring pieces; or, The length of each of the spring pieces protruding from the side is greater than the radius of the rolling element that abuts against the spring piece.

13. The rear wheel steering system according to any one of claims 1-12, characterized in that, The inner wall of the housing is a circumferential surface. During the process of one of the rotary input components stopping rotation, each of the elastic components is used to drive two of the two rolling components in a pair to abut against the inner wall of the housing and the same side surface respectively to lock the rotation of one of the rotary output components.

14. The rear wheel steering system according to any one of claims 1-13, characterized in that, In the pair of rolling elements, both rolling elements are cylindrical, and the central axis of each rolling element is parallel to the axial direction of the rotating output element. The cylindrical diameters of the two rolling elements are equal.

15. A vehicle, characterized in that, The vehicles include: One or more rear wheels; and The rear wheel steering system as described in any one of claims 1-14, wherein the rear wheel steering system is used to drive the one or more rear wheels to change steering.

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