Vehicle rear wheel active steering device and vehicle

Abstract

The invention provides a vehicle rear wheel active steering device and a vehicle, and relates to the technical field of vehicles, the vehicle rear wheel active steering device comprises a driving part, a transmission mechanism, a transmission shaft structure and two fork arm assemblies, and the two axial ends of the transmission shaft structure are connected with the corresponding fork arm assemblies respectively; the ends, away from the transmission shaft structure, of the two fork arm assemblies are used for being connected with corresponding rear wheels of the vehicle correspondingly. The driving part is connected with the transmission mechanism, the transmission shaft structure is connected with the transmission mechanism, and the transmission shaft structure is used for converting rotary motion of the transmission mechanism into axial motion of the transmission mechanism; the transmission shaft structure is used for being in sliding fit with a limiting piece arranged on a chassis, and the limiting piece is used for limiting rotation of the transmission shaft structure. On the basis that the active steering action of the rear wheels is achieved, rotation of the transmission shaft structure is limited through the limiting piece.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicles, and in particular to a vehicle rear wheel active steering device and a vehicle. Background Art

[0002] In most cases, the rear wheels of two-wheel drive vehicles do not have a steering function. For example, the two-wheel drive system of the transmission is mainly divided into front-wheel drive and rear-wheel drive. For front-wheel drive vehicles, the front wheels are responsible for steering and driving, and for rear-wheel drive vehicles, the rear wheels are responsible for driving and the front wheels are responsible for steering. This design can ensure the normal operation and driving safety of the vehicle. With the development of automobile technology, some vehicles use four-wheel steering, which can steer not only the front wheels but also the rear wheels.

[0003] In the related art, a vehicle adopting four-wheel steering usually has a rear-wheel active steering device installed on the rear axle of the vehicle, which mainly includes a drive motor, an input gear, a nut member with a toothed structure, a lead screw and a fork arm assembly. The two ends of the lead screw are respectively connected to the left steering knuckle arm and the right steering knuckle arm of the vehicle through the fork arm assembly, and the nut member is sleeved outside the lead screw, and the toothed structure of the nut member is meshed and connected with the input gear; when performing steering operations, the motor shaft of the drive motor can be connected to the input gear, so that the input gear can be driven to rotate by the drive motor, and the nut member is driven to rotate by the input gear, and the nut member converts the rotational motion of the input gear into the left and right linear motion of the lead screw, so that the steering knuckle arm can be driven to move linearly through the lead screw via the fork arm assembly to realize the steering operation of the rear wheel at a certain angle.

[0004] However, if the connection between the nut and the lead screw becomes loose, the lead screw may rotate along with the nut, thereby failing to safely achieve active steering of the rear wheels. Summary of the invention

[0005] The problem solved by the present invention is how to safely realize the active steering action of the rear wheels.

[0006] In order to solve the above problems, the present invention provides a vehicle rear wheel active steering device and a vehicle.

[0007] In a first aspect, the present invention provides a vehicle rear wheel active steering device, comprising a driving unit, a transmission mechanism, a transmission shaft structure and two fork arm assemblies, wherein the axial ends of the transmission shaft structure are respectively connected to the corresponding fork arm assemblies, and one end of the two fork arm assemblies away from the transmission shaft structure is used to respectively connect to two corresponding rear wheels of the vehicle; the driving unit is connected to the transmission mechanism, the transmission shaft structure is connected to the transmission mechanism, and the transmission shaft structure is used to convert the rotational motion of the transmission mechanism into its own axial movement;

[0008] The transmission shaft structure is used for sliding cooperation with a limiting member arranged on the chassis, and the limiting member is used for limiting the rotation of the transmission shaft structure.

[0009] Optionally, a limiting portion is provided on the transmission shaft structure, a limiting groove is provided on the limiting member, and an installation groove is provided on the transmission shaft structure. Part of the limiting portion is inserted into the corresponding installation groove, the transmission shaft structure and the limiting portion are arranged in the limiting groove, and the limiting portion is slidably matched with the inner wall of the limiting groove.

[0010] Optionally, the transmission shaft structure is provided with two installation grooves which are symmetrically distributed along its radial direction, and parts of the two limiting parts are respectively inserted into the corresponding two installation grooves, and the end surface of the limiting part away from the transmission shaft structure is slidably matched with the inner side wall of the limiting groove.

[0011] Optionally, the transmission mechanism includes a turbine and a retaining frame, the driving portion is drivingly connected to the turbine, the turbine has a helical tooth portion in the circumference, one end of the retaining frame is connected to the transmission shaft structure, the end of the retaining frame away from the transmission shaft structure penetrates into the helical tooth portion, and the side wall of the helical tooth portion abuts against the retaining frame, and the retaining frame is used to convert the rotational motion of the turbine into axial movement of the transmission shaft structure.

[0012] Optionally, the retaining frame includes a bearing seat and a connecting frame, the bearing seat is sleeved on the transmission shaft structure, and the connecting frame is connected to one end of the bearing seat away from the transmission shaft.

[0013] Optionally, the retaining frame also includes a rolling element, and a first accommodating cavity is arranged between one end of the bearing seat away from the transmission shaft structure and the connecting frame, a part of the rolling element is in the first accommodating cavity, and another part of the rolling element is in the spiral tooth portion, and the two are rollingly connected.

[0014] Optionally, the transmission mechanism includes a transmission assembly, a gearbox assembly and a flange nut, the transmission shaft structure includes a connecting shaft portion and a screw portion, the driving portion is connected to the transmission assembly, the input end of the gearbox assembly is transmission-connected to the transmission assembly, the output end of the gearbox assembly is connected to the flange nut, the flange nut is sleeved outside the screw portion, one end of the screw portion is connected to one of the fork arm assemblies, and the other end of the screw portion is connected to another of the fork arm assemblies via the connecting shaft portion;

[0015] The connecting shaft portion is used for sliding cooperation with the limiting member.

[0016] Optionally, the transmission assembly includes a driving wheel, a driven wheel and a transmission component, the driving portion is connected to the driving wheel for driving the driving wheel to rotate, the driven wheel is sleeved on the connecting shaft and is transmission-connected to the gearbox assembly, and the driving wheel and the driven wheel are connected via the transmission component.

[0017] Optionally, the gearbox assembly includes a sun gear, a ring gear, a plurality of planetary gears and a plurality of connecting pins, the ring gear has internal teeth, a plurality of planetary gears are arranged in the ring gear in an annular manner and are respectively meshed with the internal teeth, a part of the sun gear is arranged in the ring gear and meshed with the planetary gears, and another part of the sun gear is fixedly connected to the driven gear;

[0018] One end of the connecting pin is connected to the corresponding planetary gear, and the other end of the connecting pin is fixedly connected to the flange nut. The planetary gear is used to drive the flange nut to rotate through the connecting pin.

[0019] Optionally, the axis of the input end of the gearbox assembly coincides with the axis of the transmission shaft structure.

[0020] Optionally, the driving part includes a housing and a stator winding, and the stator winding is arranged in the housing; the transmission mechanism includes a rotor nut and a magnetic tile, the magnetic tile is coaxial with the rotor nut and fixedly connected, the stator winding is sleeved on the magnetic tile, and the stator winding is used to drive the magnetic tile to drive the rotor nut to rotate;

[0021] The transmission shaft structure includes a screw part and two connecting shaft parts. The rotor nut is sleeved outside the screw part. Both ends of the screw part are respectively connected to the corresponding connecting shaft parts. The connecting shaft parts are used for sliding cooperation with the limit member.

[0022] Optionally, a plurality of fixing grooves are provided in the circumference of the rotor nut, and the magnetic tile includes a plurality of magnetic tile monomers, and the magnetic tile monomers are installed in corresponding fixing grooves.

[0023] Optionally, the outer shell includes a motor shell and an end cover, the motor shell is a shell structure with a second accommodating cavity inside and an open end, and the end cover is arranged at the opening of the motor shell; the stator winding is embedded in the second accommodating cavity of the motor shell, and the end of the screw part passes through the end cover and is connected to the corresponding connecting shaft part.

[0024] In a third aspect, the present invention provides a vehicle, comprising rear wheels and the vehicle rear wheel active steering device as described above.

[0025] The vehicle rear wheel active steering device and the vehicle of the present invention have the following beneficial effects:

[0026] The vehicle rear wheel active steering device mainly includes a driving unit, a transmission mechanism, a transmission shaft structure and two fork arm assemblies. For example, the driving unit can be electrically connected to the vehicle's motor controller, and the motor controller can be electrically connected to the vehicle controller. When the rear wheels of the vehicle need to steer, the vehicle speed signal, the rear wheel steering angle signal, and the rear wheel steering speed signal can be transmitted to the motor controller through the vehicle controller, so as to control the output shaft of the driving unit to rotate through a predetermined control program of the motor controller to drive the transmission mechanism to rotate, and the transmission shaft structure is connected to the transmission mechanism to convert the rotational motion of the transmission mechanism into its own axial movement through the transmission shaft structure, and the two ends of the transmission shaft structure are respectively connected to the corresponding fork arm assemblies, and the end of the fork arm assembly away from the transmission shaft structure can be connected to the corresponding rear wheel of the vehicle, so that the axial movement of the transmission shaft structure can realize the active steering action of the rear wheel through the fork arm assembly.

[0027] Since the limiter can be fixedly installed on the chassis of the vehicle, and the transmission shaft structure and the limiter are slidably matched so that the transmission shaft structure can move axially relative to the limiter, the limiter can limit the radial rotation of the transmission shaft structure along with the transmission mechanism, thereby realizing safe active steering action of the rear wheels. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the structure of the vehicle rear wheel active steering device in an embodiment of the present invention.

[0029] Figure 2 It is a schematic diagram of the exploded structure of the limiter and the transmission shaft structure in the embodiment of the present invention.

[0030] Figure 3 It is a schematic diagram of the assembly structure of the limit member and the transmission shaft structure in an embodiment of the present invention.

[0031] Figure 4 The figure is a schematic structural diagram of a vehicle rear wheel active steering device in one embodiment of the present invention.

[0032] Figure 5 Schematic diagram of the structure of a retaining frame in one embodiment of the present invention.

[0033] Figure 6 Schematic diagram of the exploded structure of a retaining frame in one embodiment of the present invention.

[0034] Figure 7 FIG. 1 is a schematic diagram of the structure of a retaining frame in another embodiment of the present invention.

[0035] Figure 8 Schematic diagram of the exploded structure of a retaining frame in another embodiment of the present invention.

[0036] Fig. 9 It is a schematic structural diagram of a vehicle rear wheel active steering device in another embodiment of the present invention.

[0037] Fig.10 This is one of the exploded structural schematic diagrams of a vehicle rear wheel active steering device in another embodiment of the present invention.

[0038] Fig.11 This is a second schematic diagram of the exploded structure of a vehicle rear wheel active steering device in another embodiment of the present invention.

[0039] Fig.12 The figure is a schematic cross-sectional structure diagram of a vehicle rear wheel active steering device in another embodiment of the present invention.

[0040] Fig.13 The figure is a schematic cross-sectional structure diagram of a vehicle rear wheel active steering device in another embodiment of the present invention.

[0041] Fig.14 The figure is a schematic structural diagram of a vehicle rear wheel active steering device in another embodiment of the present invention.

[0042] Fig.15 It is a schematic structural diagram of a driving part and a transmission mechanism in another embodiment of the present invention.

[0043] Fig.16 It is a schematic structural diagram of the rotor nut and the magnetic shoe in another embodiment of the present invention.

[0044] Description of reference numerals:

[0045] 1-limiting member; 111-limiting groove; 2-driving part; 21-housing; 211-motor housing; 212-end cover; 213-oil seal; 22-stator winding; 221-stator coil; 222-coil bracket; 3-transmission mechanism; 31-turbine; 311-helical tooth portion; 32-retaining frame; 321-bearing seat; 3211-first groove; 322-connecting frame; 3221-second groove; 3222-installing part; 3223-connecting part; 323-rolling element; 33-transmission assembly; 331-driving wheel; 332-driven wheel; 3 33-transmission parts; 34-gearbox assembly; 341-sun gear; 342-gear ring; 343-planetary gear; 344-connecting pin; 345-first bearing; 346-second bearing; 347-third bearing; 348-fourth bearing; 35-flange nut; 36-rotor nut; 361-fixing groove; 37-magnetic tile; 38-fifth bearing; 39-sixth bearing; 4-transmission shaft structure; 41-connecting shaft; 410-installation groove; 42-screw part; 5-fork arm assembly; 51-fork arm connecting shaft; 52-fork arm body; 6-limiting part. DETAILED DESCRIPTION

[0046] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be interpreted as being limited to the embodiments described herein. On the contrary, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present invention.

[0047] The Z axis in the drawings represents the vertical direction, that is, the up and down position, and the positive direction of the Z axis represents the top, and the reverse direction of the Z axis represents the bottom; the X axis in the drawings represents the horizontal direction, and is designated as the front and back position, and the positive direction of the X axis represents the front side, and the reverse direction of the X axis represents the back side; the Y axis in the drawings represents the left and right position, and the positive direction of the Y axis represents the left side, and the reverse direction of the Y axis represents the right side. It should also be noted that the aforementioned Z axis, Y axis, and X axis are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0048] The term "including" and its variations used in this document are open inclusions, that is, "including but not limited to"; the term "based on" means "based at least in part on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments". The relevant definitions of other terms will be given in the following description. It should be noted that the concepts of "first", "second", etc. mentioned in the present invention are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units.

[0049] It should be noted that the modifications of "one" and "plurality" mentioned in the present invention are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise clearly indicated in the context, it should be understood as "one or more".

[0050] In view of the problems existing in the above-mentioned related technologies, this embodiment provides a vehicle rear wheel active steering device and a vehicle.

[0051] like Figure 1As shown, an embodiment of the present invention provides a vehicle rear wheel active steering device, comprising a driving unit 2, a transmission mechanism 3, a transmission shaft structure 4 and two fork arm assemblies 5, wherein the axial ends of the transmission shaft structure 4 are respectively connected to the corresponding fork arm assemblies 5, and the ends of the two fork arm assemblies 5 away from the transmission shaft structure 4 are used to respectively connect to the two corresponding rear wheels of the vehicle; the driving unit 2 is connected to the transmission mechanism 3, the transmission shaft structure 4 is connected to the transmission mechanism 3, and the transmission shaft structure 4 is used to convert the rotational motion of the transmission mechanism 3 into its own axial movement;

[0052] The transmission shaft structure 4 is used for sliding cooperation with the limiting member 1 arranged on the chassis, and the limiting member 1 is used for limiting the rotation of the transmission shaft structure 4 .

[0053] Specifically, the driving part 2 is used to drive the transmission mechanism 3 to rotate, so the driving part 2 can be a rotation driving device, such as a rotary motor. A part of the transmission mechanism 3 is connected to the driving part 2, and another part can be connected to the transmission shaft structure 4, so the transmission mechanism 3 can be used as a transmission structure between the driving part 2 and the transmission shaft structure 4. The axial direction of the transmission shaft structure 4 can be connected to the transmission shaft structure 4. Figure 1 The Y-axis direction in the coordinate system is parallel, and the two fork arm assemblies 5 can be respectively arranged at the axial ends of the transmission shaft structure 4. The end of each fork arm assembly 5 away from the transmission shaft structure 4 can be directly connected to a corresponding rear wheel of the vehicle, or connected through other structures such as the steering knuckle arm of the vehicle, and the steering knuckle arm can be connected to the frame and the corresponding rear wheel.

[0054] The limit member 1 may not be a component of the vehicle's rear wheel active steering device. The limit member 1 can be fixedly installed on the vehicle's chassis, such as an axle. The transmission shaft structure 4 is slidably matched with the limit member 1, so the transmission shaft structure 4 can move linearly along its own axis relative to the limit member 1, but the limit member 1 can limit the radial rotation of the transmission shaft structure 4.

[0055] The limiting member 1 can limit the radial rotation of the transmission shaft structure 4 in the following manner. For example, if the radial cross section of the transmission shaft structure 4 (for example, along the Figure 1 The cross section of the XZ plane in the coordinate system is a polygonal structure. In other words, at least the portion where the transmission shaft structure 4 is connected to the stopper 1 can be a multi-prism structure, and the stopper 1 can be provided with a stopper groove that matches the shape of the transmission shaft structure 4. Of course, the stopper 1 and the transmission shaft structure 4 can also adopt other structural solutions to allow the transmission shaft structure 4 to move linearly relative to the stopper 1 along its own axial direction, while limiting the rotation of the transmission shaft structure 4.

[0056] In this embodiment, the vehicle rear wheel active steering device mainly includes a driving unit 2, a transmission mechanism 3, a limiter 1, a transmission shaft structure 4 and two fork arm assemblies 5. By way of example, the driving unit 2 can be electrically connected to the vehicle's motor controller, and the motor controller can be electrically connected to the vehicle controller. When the rear wheels of the vehicle need to steer, the vehicle speed signal, the rear wheel steering angle signal, and the rear wheel steering speed signal can be transmitted to the motor controller through the vehicle controller, so as to control the output shaft of the driving unit 2 to rotate through a control program set by the motor controller, so as to drive the transmission mechanism 3 to rotate, and the transmission shaft structure 4 is connected to the transmission mechanism 3, so as to convert the rotational movement of the transmission mechanism 3 into its own axial movement through the transmission shaft structure 4, and the two ends of the transmission shaft structure 4 are respectively connected to the corresponding fork arm assemblies 5, and the end of the fork arm assembly 5 away from the transmission shaft structure 4 can be connected to the corresponding rear wheel of the vehicle, so that the axial movement of the transmission shaft structure 4 can realize the active steering action of the rear wheel through the fork arm assembly 5.

[0057] Since the limit member 1 can be fixedly installed on the chassis of the vehicle, and the transmission shaft structure 4 is slidably matched with the limit member 1, so that the transmission shaft structure 4 can move axially relative to the limit member 1, the limit member 1 can limit the radial rotation of the transmission shaft structure 4 along with the transmission mechanism 3, thereby realizing safe active steering action for the rear wheels.

[0058] Optionally, combined Figure 2 As shown, a limiting portion 6 is provided on the transmission shaft structure 4, a limiting groove 111 is provided on the limiting member 1, and an installation groove 410 is provided on the transmission shaft structure 4. Part of the limiting portion 6 is inserted into the corresponding installation groove 410, and the transmission shaft structure 4 and the limiting portion 6 are arranged in the limiting groove 111, and the limiting portion 6 is slidably matched with the inner wall of the limiting groove 111; when the transmission shaft structure 4 has a rotation tendency, the limiting portion 6 is abutted against the inner wall of the limiting groove 111 to limit the rotation of the transmission shaft structure 4.

[0059] Specifically, a mounting groove 410 can be opened on the transmission shaft structure 4, and the limiting portion 6 can be partially installed in the mounting groove 410 in the following manner. For example, the limiting portion 6 includes a limiting plate and a boss. The boss and the limiting plate can be constructed as an integral structure, and the boss can be inserted into the mounting groove 410, so that when the boss of the limiting portion 6 is embedded in the mounting groove 410, the limiting portion 6 will not separate from the mounting groove 410 in the vertical direction.

[0060] The limiting groove 111 can be a rectangular groove, and the extending direction of the rectangular groove can be Figure 2Parallel to the Y-axis direction in the coordinate system; the limiting portion 6 and the transmission shaft structure 4 can be placed in the limiting groove 111 of the limiting member 1, and the end face of the limiting portion 6 away from the transmission shaft structure 4 can be fitted with the inner side wall of the limiting groove 111 along the direction perpendicular to the extension direction of the transmission shaft structure 4, or a gap can be reserved so that the transmission shaft structure 4 can smoothly perform axial linear movement in the limiting groove 111.

[0061] The transmission shaft structure 4 may be directly slidably matched with the position-limiting member 1 , or the transmission shaft structure 4 may be slidably matched with the position-limiting groove 111 of the position-limiting member 1 through other components such as the position-limiting portion 6 .

[0062] The limiting portion 6 can also limit the rotation of the transmission shaft structure 4 in the following manner. For example, the transmission shaft structure 4 is basically a cylindrical structure as a whole, and the limiting portion 6 is a planar structure arranged on the transmission shaft structure 4. In other words, the transmission shaft structure 4 is provided with two planar structures distributed radially symmetrically, and the dimension between the two planar structures is smaller than the diameter of other parts of the transmission shaft structure 4. The spacing between the two relative inner walls of the limiting groove 111 of the limiting member 1 is slightly greater than or equal to the dimension between the two planar structures on the transmission shaft structure 4. When the planar structure of the transmission shaft structure 4 is in the limiting groove 111 of the limiting member 1, the gaps between the two relative inner walls of the limiting groove 111 and the two planar structures of the transmission shaft structure 4 are very small, which can also limit the rotation of the transmission shaft structure 4.

[0063] In this optional embodiment, since a portion of the limiting portion 6 is inserted into the mounting groove 410 corresponding to the transmission shaft structure 4, the other portion of the limiting portion 6 can protrude from the mounting groove 410 and be located in the limiting groove 111 of the limiting member 1; when the limiting portion 6 and the transmission shaft structure 4 are installed in the limiting groove 111 of the limiting member 1, since the limiting plate portion of the limiting portion 6 slides with the inner wall of the limiting groove 111, the limiting plate with a planar structure of the limiting portion 6 corresponds to the inner side wall of the limiting groove 111, so that the limiting plate of the limiting portion 6 can fit with the inner side wall of the limiting groove 111 or have a small gap. In other words, the internal gap of the limiting groove 111 is effectively reduced, thereby limiting the radial rotation of the transmission shaft structure 4 along the transmission mechanism 3.

[0064] Figure 2 It can be a schematic diagram of the exploded structure of the two limiting parts 6 in the limiting member 1, the transmission shaft structure 4 and the limiting member 1 before assembly. Figure 3 It can be a schematic diagram of the assembly structure of the two limiting parts 6 in the limiting member 1, the transmission shaft structure 4 and the limiting member 1 after assembly.

[0065] Optionally, combined Figure 2 and Figure 3As shown, the limiting member 1 includes two limiting portions 6, and the transmission shaft structure 4 is provided with two installation grooves 410 which are symmetrically distributed along its radial direction. Parts of the two limiting portions 6 are respectively inserted into the corresponding two installation grooves 410, and the end face of the limiting portion 6 away from the transmission shaft structure 4 is slidably matched with the inner side wall of the limiting groove 111.

[0066] Specifically, the radial direction can be Figure 3 The X-axis direction of the middle coordinate system is parallel, and the transmission shaft structure 4 can extend along its own radial direction ( Figure 3 Mounting grooves 410 are respectively provided at both ends (in the X-axis direction), and parts of the two limiting parts 6 can be respectively inserted into the corresponding mounting grooves 410.

[0067] The end surface of the limiting portion 6 away from the transmission shaft structure 4 refers to the limiting portion 6 along the Figure 3 The end surface in the X-axis direction of the coordinate system.

[0068] In this optional embodiment, when the transmission shaft structure 4 and the two limiting portions 6 are installed in the limiting groove 111 of the limiting member 1, the internal clearance of the limiting groove 111 can be further reduced by the transmission shaft structure 4 and the two limiting portions 6 arranged radially therefrom, thereby further limiting the radial rotation of the transmission shaft structure 4 along the transmission mechanism 3.

[0069] Furthermore, a guide rib can be provided on the inner side wall of the limiting groove 111 of the limiting member 1, and a guide groove is provided on the end face of the limiting portion 6 away from the transmission shaft structure 4, and at least a part of the guide rib is embedded in the guide groove. Thus, on the basis of realizing the linear sliding of the transmission shaft structure 4 and the limiting portion 6 in the limiting groove 111, the directional movement of the limiting portion 6 in the limiting groove 111 is further ensured, and the axial linear movement of the limiting portion 6 in the limiting groove 111 is prevented from being tilted. Moreover, the guide rib in the limiting groove 111 and the guiding groove on the limiting portion 6 are slidably matched, which can further effectively limit the radial rotation of the transmission shaft structure 4.

[0070] In the related art, a vehicle adopting four-wheel steering usually has a rear-wheel active steering device installed on the rear axle of the vehicle, which mainly includes a drive motor, an input gear, a nut member with a toothed structure, a lead screw and a fork arm assembly. The two ends of the lead screw are respectively connected to the left and right steering knuckle arms of the vehicle through the fork arm assembly, and the nut member is sleeved outside the lead screw. The toothed structure of the nut member is meshed and connected with the input gear. When performing steering operations, the motor shaft of the drive motor can be connected to the input gear to drive the input gear to rotate through the drive motor, and the input gear drives the nut member to rotate. The nut member converts the rotational motion of the input gear into the left and right linear motion of the lead screw, so that the steering knuckle arm is driven to rotate through the lead screw via the fork arm assembly to achieve steering operations of the rear wheels at a certain angle.

[0071] Since the self-locking property is inversely proportional to the transmission efficiency, the lead screw used in the above-mentioned rear-wheel active steering device has a self-locking characteristic, that is, only the above-mentioned rear-wheel active steering device can push the rear wheels to steer, and the rear wheels cannot push the rear-wheel active steering device to steer; and the way to improve the self-locking property is mainly to increase the friction coefficient. Since the transmission between the nut member sleeved outside the lead screw and the gear is sliding friction, it is necessary to increase the output power of the drive motor to overcome this sliding friction, resulting in a low transmission efficiency of the above-mentioned rear-wheel active steering device, and also increasing the size, cost and energy consumption of the drive motor.

[0072] Optionally, combined Figure 4 As shown, the transmission mechanism 3 includes a turbine 31 and a retaining frame 32, the driving portion 2 is drivingly connected to the turbine 31, the turbine 31 has a helical tooth portion 311 in the circumference, one end of the retaining frame 32 is connected to the transmission shaft structure 4, the end of the retaining frame 32 away from the transmission shaft structure 4 is deep in the helical tooth portion 311, and the side wall of the helical tooth portion 311 is in contact with the retaining frame 32, and the retaining frame 32 is used to convert the rotational motion of the turbine 31 into the axial movement of the transmission shaft structure 4.

[0073] Specifically, one end of the retaining frame 32 and the transmission shaft structure 4 can be connected by interference fit, fixed sleeve connection, welding or the like, so that the retaining frame 32 can drive the transmission shaft structure 4 to move linearly.

[0074] The driving part 2 may adopt a driving motor, and the turbine 31 may be a rod-shaped structure having a helical tooth portion 311, so the output shaft of the driving part 2 may be fixedly connected to the central hole of the turbine 31 to drive the turbine 31 to rotate. The turbine 31 is provided with a helical tooth portion 311 in the circumference, and the helical tooth portion 311 has a helical groove, and the end of the retainer 32 away from the transmission shaft structure 4 may be in the helical groove of the helical tooth portion 311, so the helical tooth portion 311 can drive the retainer 32 and the transmission shaft structure 4 to perform axial linear movement.

[0075] In this optional embodiment, one end of the retaining frame 32 is fixedly connected to the transmission shaft structure 4 so that the retaining frame 32 can perform synchronous axial movement with the transmission shaft structure 4; when the rear wheel needs to be turned, the turbine 31 can be driven to rotate by the driving unit 2, so that the retaining frame 32 can be used to convert the rotational motion of the turbine 31 into axial movement of the transmission shaft structure 4, and the end of the transmission shaft structure 4 can be connected to the frame and the rear wheel via the fork arm assembly 5, so that the steering action of the rear wheel can be achieved by the axial movement of the transmission shaft structure 4; wherein, the steering action of the rear wheel, such as left steering or right steering, is directly related to the forward and reverse rotation of the driving unit 2 (driving motor), for example, if the output shaft of the driving unit 2 rotates clockwise, the rear wheel can turn left, conversely, if the output shaft of the driving unit 2 rotates counterclockwise, the rear wheel can turn right.

[0076] In addition, compared with the screw nut gear mechanism used in the above-mentioned related art, the vehicle rear wheel active steering device of the present invention adopts a combined design of a turbine 31 and a retainer 32, and adjusts the sliding friction motion of the screw nut mechanism to the rolling friction motion of the turbine 31 and the retainer 32, thereby improving the working efficiency of the vehicle rear wheel active steering device and optimizing the size, cost and energy loss of the motor. In addition, the drive unit 2 uses a drive motor as the power unit input of the transmission mechanism 3, and the response speed is faster than the follow-up steering, and the steering angle can be accurately controlled.

[0077] Optionally, combined Figures 5 to 8 As shown, the retaining frame 32 includes a bearing seat 321 and a connecting frame 322. The bearing seat 321 is sleeved on the transmission shaft structure 4. The connecting frame 322 is connected to the end of the bearing seat 321 away from the transmission shaft structure 4. The end of the connecting frame 322 away from the bearing seat 321 is deep into the spiral tooth portion 311.

[0078] Specifically, the retaining frame 32 may include two parts, such as a bearing seat 321 and a connecting frame 322. The bearing seat 321 and the transmission shaft structure 4 may be connected by interference fit, so that the bearing seat 321 can drive the transmission shaft structure 4 to move linearly. One end of the bearing seat 321 away from the transmission shaft structure 4 may be fixedly connected to the connecting frame 322 by a first fastener, and the first fastener may be a bolt structure.

[0079] The connecting frame 322 can adopt the following structure, combined with Figure 6 As shown, for example, the connecting frame 322 may include a mounting portion 3222 and two connecting portions 3223, and the opposite ends of the mounting portion 3222 are respectively connected to the corresponding connecting portions 3223, and the mounting portion 3222 and the two connecting portions 3223 may be constructed as an integrated structure, thereby ensuring the mechanical strength of the connecting frame 322; the two first fasteners are respectively penetrated through the corresponding connecting portions 3223 of the connecting frame 322 and the bearing seat 321 to realize the fixed connection between the connecting frame 322 and the bearing seat 321.

[0080] Optionally, combined Figure 5 and Figure 7 As shown, the retaining frame 32 also includes a rolling element 323, and a first accommodating cavity is arranged between the end of the bearing seat 321 away from the transmission shaft structure 4 and the connecting frame 322, a part of the rolling element 323 is in the first accommodating cavity, and another part of the rolling element 323 is in the spiral tooth portion 311, and the two are rollingly connected.

[0081] Specifically, a first accommodating cavity can be preset between the end of the bearing seat 321 away from the transmission shaft structure 4 and the connecting frame 322, and a part of the rolling element 323, for example most of it, can be embedded in the first accommodating cavity. At this time, the bearing seat 321 and the connecting frame 322 can provide installation space for the installation of the rolling element 323; another part of the rolling element 323 can protrude from the first accommodating cavity and be rollingly connected with the spiral tooth portion 311.

[0082] The connecting frame 322 can be fixedly connected to the bearing seat 321 through two first fasteners, and the rolling element 323 can be located between the two first fasteners. When the two first fasteners are inserted through the connecting frame 322 and the bearing seat 321, the connection strength between the connecting frame 322 and the bearing seat 321 on the opposite sides of the rolling element 323 is the same, further reducing the possibility of the rolling element 323 detaching from the first accommodating cavity.

[0083] In addition, combined Figure 4 and Figure 5 As shown, the width of the mounting portion 3222 is less than the width of the two connecting portions 3223. Specifically, the width of the mounting portion 3222 and the connecting portion 3223 refers to the width of the mounting portion 3222 and the connecting portion 3223 along the Figure 4 The dimension in the Y-axis direction in the coordinate system; since the width of the mounting portion 3222 is smaller than the width of the two connecting portions 3223, it is helpful for the mounting portion 3222 and the rolling element 323 to be located in two adjacent threads of the helical tooth portion 311 of the turbine 31; moreover, the two connecting portions 3223 are located on opposite sides of the mounting portion 3222, and the width of the connecting portion 3223 is larger than the pitch of the turbine 31, so that the transmission stability of the mounting portion 3222 of the turbine 31 and the connecting frame 322 can be improved through the two connecting portions 3223 on both sides of the mounting portion 3222.

[0084] Combination Figure 5 and Figure 6 As shown, the rolling element 323 may be a ball; Figure 7 and Figure 8 As shown, the rolling element 323 may be a cylindrical structure.

[0085] In this optional embodiment, part of the rolling element 323 can be embedded in the first accommodating cavity to provide an installation base or installation space for the rolling element 323 through the first accommodating cavity; and the other part of the rolling element 323 protrudes from the first accommodating cavity and is rollingly connected with the helical tooth portion 311 of the turbine 31, so that the point contact between the turbine 31 and the connecting frame 322 can be converted into a line contact through the rolling element 323, so as to increase the contact area between the turbine 31 and the retaining frame 32, and the rolling element 323 can not only better transmit the rotational force of the turbine 31 to the connecting frame 322, but also increase the thrust coverage of the turbine 31 on the retaining frame 32, thereby correspondingly increasing the service life of the retaining frame 32.

[0086] Optionally, combined Figure 6 and Figure 8 As shown, a first groove 3211 is provided at one end of the bearing seat 321 away from the transmission shaft, and a second groove 3221 corresponding to the first groove 3211 is provided on the connecting frame 322, and the first groove 3211 and the second groove 3221 form the first accommodating cavity.

[0087] Specifically, the rolling member 323 may be installed in the first accommodating cavity in the following manner. For example, a first groove 3211 may be opened in the middle of the end of the bearing seat 321 away from the transmission shaft, and the first groove 3211 may be a circular structure. A second groove 3221 may be opened at the end of the connecting frame 322 opposite to the bearing seat 321, and the second groove 3221 may be a semicircular structure. The first groove 3211 and the second groove 3221 may form a first accommodating cavity.

[0088] In this optional embodiment, when the rolling member 323 is installed in the first accommodating cavity surrounded by the first groove 3211 and the second groove 3221, the assembly positions of the connecting frame 322 and the bearing seat 321 are aligned, and a first fastener is passed through the connecting frame 322 and the bearing seat 321 to realize the assembly and fixation of the connecting frame 322 and the bearing seat 321, so that the rolling member 323 can be restricted by the first accommodating cavity surrounded by the first groove 3211 and the second groove 3221, so that the rolling member 323 can rotate in the first accommodating cavity but will not be separated from the first accommodating cavity.

[0089] In the above-mentioned related technologies, the rear-wheel active steering device mainly adopts a nut part and a gear as a transmission mechanism between the motor and the lead screw; since the self-locking property is inversely proportional to the transmission efficiency, the lead screw used in the above-mentioned rear-wheel active steering device has a self-locking characteristic, that is, only the above-mentioned rear-wheel active steering device can push the rear wheel to steer, and the rear wheel cannot push the rear-wheel active steering device to steer; and the way to improve the self-locking property is mainly to increase the friction coefficient. Since the transmission between the nut part and the gear mounted outside the lead screw is sliding friction, it is necessary to increase the output power of the drive motor to overcome this sliding friction, resulting in a low transmission efficiency of the above-mentioned rear-wheel active steering device, and also increasing the size, cost and energy consumption of the drive motor.

[0090] Optionally, combined Fig. 9 and Fig.11As shown, the transmission mechanism 3 includes a transmission assembly 33, a gear box assembly 34 and a flange nut 35, the transmission shaft structure 4 includes a connecting shaft portion 41 and a screw portion 42, the driving portion 2 is connected to the transmission assembly 33, the input end of the gear box assembly 34 is in transmission connection with the transmission assembly 33, the output end of the gear box assembly 34 is connected to the flange nut 35, the flange nut 35 is sleeved outside the screw portion 42, one end of the screw portion 42 is connected to one of the fork arm assemblies 5, and the other end of the screw portion 42 is connected to another fork arm assembly 5 via the connecting shaft portion 41;

[0091] The connecting shaft portion 41 is used for sliding cooperation with the limiting member 1 .

[0092] Specifically, the driving part 2 can be a rotating motor, so the output shaft of the driving part 2 can be fixedly connected to the transmission assembly 33 to drive the transmission assembly 33 to rotate. The transmission assembly 33 and the flange nut 35 can be distributed outside the gear box assembly 34 along the axial interval of the transmission shaft structure 4, so the gear box assembly 34 has an input end and an output end, the input end of the gear box assembly 34 can be connected to the transmission assembly 33, and the output end of the gear box assembly 34 can be connected to the flange nut 35, so that the gear box assembly 34 can transmit the rotational force of the transmission assembly 33 to the flange nut 35.

[0093] The transmission shaft structure 4 may include a screw portion 42 and at least one connecting shaft portion 41, one end of the connecting shaft portion 41 may be connected to a fork arm assembly 5, the other end of the connecting shaft portion 41 may be connected through one end of the screw portion 42, and the other end of the screw portion 42 may be directly connected to another fork arm assembly 5 (see Figures 9 to 12 Alternatively, the other end of the screw portion 42 may be connected to another fork arm assembly 5 via another connecting shaft portion 41 (not shown in the figure).

[0094] The flange nut 35 is sleeved on the outside of the screw part 42, and the screw part 42 is used to convert the rotational motion of the flange nut 35 into its own axial movement.

[0095] Combination Fig. 9 As shown, the limiting member 1 is provided with a limiting groove 111, and the connecting shaft portion 41 is provided with a limiting portion 6, and the connecting shaft portion 41 can be embedded in the limiting groove 111 through the limiting portion 6; Fig.11 As shown, a mounting groove 410 can be provided on the connecting shaft portion 41, and a portion of the limiting portion 6 is inserted into the mounting groove 410; Fig. 9 As shown, the connecting shaft portion 41 and the limiting portion 6 of the transmission shaft structure 4 are both installed in the limiting groove 111 , and the connecting shaft portion 41 and the limiting portion 6 can move linearly in the limiting groove 111 .

[0096] In this optional embodiment, when the rear wheel needs to be steered, the drive unit 2 can be used to drive the transmission assembly 33 to rotate, and the transmission assembly 33 transmits the rotational force of the drive unit 2 to the flange nut 35 through the gear box assembly 34, so as to drive the flange nut 35 to rotate synchronously, and the flange nut 35 is sleeved outside the screw unit 42, so as to utilize the screw unit 42 to convert the rotational motion of the flange nut 35 into the axial movement of the screw unit 42 itself, and one end of the screw unit 42 can be connected to a fork arm assembly 5, and the other end of the screw unit 42 can be connected to the shaft Part 41 is connected to another fork arm assembly 5, and the two fork arm assemblies 5 are respectively connected to the frame and the rear wheel through the corresponding steering knuckle arms, so that the axial movement force of the fork arm assembly 5 and the steering knuckle arm can be transmitted to the rear wheel through the screw part 42 to realize the steering action of the rear wheel; wherein, the steering action of the rear wheel, such as left steering or right steering, is directly related to the forward and reverse rotation of the driving part 2 (driving motor), for example, if the output shaft of the driving part 2 rotates clockwise, the rear wheel can turn left, conversely, if the output shaft of the driving part 2 rotates counterclockwise, the rear wheel can turn right.

[0097] In addition, compared with the screw nut gear mechanism used in the above-mentioned related art, the vehicle rear wheel active steering device of the present invention adopts a combination design of a transmission assembly 33, a gear box assembly 34 and a screw 42. Specifically, the gear box assembly 34 can achieve the effect of reducing speed and increasing torque, and has the advantages of compact structure, small size, light weight, etc., so as to make up for the problem of low transmission efficiency of the screw nut gear mechanism in the above-mentioned related art, reduce the output power of the drive unit 2 such as the rotating motor, and correspondingly reduce the size, cost, energy loss, etc. of the motor. In addition, the drive unit 2 uses a drive motor as the power unit input of the transmission mechanism 3, the response speed is faster than the follow-up steering, and the steering angle can be accurately controlled.

[0098] Optionally, combined Figures 10 to 12 As shown, the transmission assembly 33 includes a driving wheel 331, a driven wheel 332 and a transmission component 333. The driving unit 2 is connected to the driving wheel 331 for driving the driving wheel 331 to rotate. The driven wheel 332 is sleeved on the connecting shaft 41 and is transmission-connected to the gearbox assembly 34. The driving wheel 331 and the driven wheel 332 are connected via the transmission component 333.

[0099] Specifically, the driving unit 2 can adopt a rotating motor, so the output shaft or motor shaft of the driving unit 2 can be fixedly connected to the center of the driving wheel 331 by interference fit or key connection, so that the driving wheel 331 can rotate synchronously with the motor shaft of the driving unit 2.

[0100] The driven wheel 332 can be sleeved outside the connecting shaft 41, and the driving wheel 331 and the driven wheel 332 can be connected via a transmission structure, so that the transmission component 333 can transmit the rotational force of the driving wheel 331 to the driven wheel 332, and the driven wheel 332 can be fixedly connected to the gear box assembly 34, so that the driven wheel 332 can transmit the rotational force to the gear box assembly 34.

[0101] Among them, if the driving wheel 331 and the driven wheel 332 are both pulleys, the transmission component 333 can be a transmission belt; if the driving wheel 331 and the driven wheel 332 have a sprocket structure, the transmission structure can be a transmission chain; preferably, the transmission component 333 is a transmission belt.

[0102] In this optional embodiment, the transmission assembly 33 can transmit the rotational force of the driving part 2 to the gear box assembly 34 in the following manner. For example, the motor shaft of the driving part 2 rotates to drive the driving wheel 331 to rotate, so as to transmit the rotational driving force of the driving wheel 331 to the driven wheel 332 through the transmission component 333. Since the driven wheel 332 is connected to the gear box assembly 34, the driven wheel 332 can transmit the rotational driving force to the gear box assembly 34. Among them, since the transmission component 333 can adopt a transmission belt, the operating noise of the transmission assembly 33 can be effectively reduced, and the corresponding transmission efficiency can be improved.

[0103] Optionally, combined Figures 10 to 12 As shown, the gearbox assembly 34 can adopt the following structure, the gearbox assembly 34 includes a sun gear 341, a ring gear 342, a plurality of planetary gears 343 and a plurality of connecting pins 344, the ring gear 342 has internal teeth, a plurality of planetary gears 343 are arranged in the ring gear 342 in an annular manner and are respectively meshed with the internal teeth, a part of the sun gear 341 is arranged in the ring gear 342 and meshed with the planetary gears 343, and another part of the sun gear 341 is fixedly connected to the driven gear 332;

[0104] One end of the connecting pin 344 is connected to the corresponding planetary gear 343 , and the other end of the connecting pin 344 is fixedly connected to the flange nut 35 . The planetary gear 343 is used to drive the flange nut 35 to rotate through the connecting pin 344 .

[0105] Specifically, the ring gear 342 is a circular ring structure with annular internal teeth. The multiple of the multiple planetary gears 343 refers to at least two, for example, three planetary gears 343 embedded in the ring gear 342, and all meshed with the internal teeth of the ring gear 342; a part of the sun gear 341 is embedded in the ring gear 342 and meshed with the planetary gears 343, and another part of the sun gear 341 protrudes from the ring gear 342 and can be fixedly connected with the driven gear 332 by interference fit (in other words, the driven gear 332 is fixedly sleeved on the other part of the sun gear 341 protruding from the ring gear 342), so that the rotational force of the driven gear 332 can be transmitted to the sun gear 341. The input end of the gearbox assembly 34 can be the sun gear 341, and the output end of the gearbox assembly 34 can be the connecting pin 344.

[0106] The number of connecting pins 344 matches the number of planetary gears 343. The connecting pins 344 can serve as the central axis of the planetary gear 343. A portion of the connecting pins 344 is located inside the planetary gear 343, and the other portion protrudes from the planetary gear 343 and can pass through the flange nut 35, so that the planetary gear 343 and the flange nut 35 are fixed as an integral structure through the connecting pins 344, so that the two can rotate synchronously.

[0107] In this optional embodiment, when it is necessary to perform a steering action of the rear wheel, the driving wheel 331 can be driven to rotate by the driving unit 2, and the driving wheel 331 can transmit the rotational force of the driving unit 2 to the flange nut 35 via the transmission component 333, the driven wheel 332, the sun gear 341, the planetary gear 343, and the connecting pin 344 in sequence. Since the flange nut 35 is sleeved outside the screw part 42, the screw part 42 can be used to convert the rotational movement of the flange nut 35 into the axial movement of the screw part 42 itself. One end of the screw part 42 can be connected to a fork arm assembly 5, and the other end of the screw part 42 can be connected to another fork arm assembly 5 via the connecting shaft part 41, and the two fork arm assemblies 5 are respectively connected to the frame and the rear wheel via the corresponding steering knuckle arms, so that the axial movement force of the screw part 42 can be transmitted to the rear wheel via the fork arm assembly 5 to realize the steering action of the rear wheel.

[0108] In addition, the gearbox assembly 34 also has the following functions. For example, the gearbox assembly 34 uses multiple planetary gears 343 evenly distributed between the internal sun gear 341 and the external ring gear 342, which can effectively balance the inertial force acting on the sun gear 341 and the planet carrier, such as the connecting pins 344 and the flange nuts 35, to improve the transmission efficiency; the gearbox assembly 34 can use multiple planetary gears 343 to simultaneously transmit motion and power to achieve a large transmission ratio, and at the same time, can achieve functions such as differential, acceleration and deceleration, and reversal; the interior of the gearbox assembly 34 is arranged at intervals through multiple connecting pins 344 and connected to the flange nuts 35, which can maintain uniform load distribution and power distribution between the planetary gears 343, significantly improving stability and the ability to resist impact and vibration; furthermore, the multiple planetary gears 343 in the ring gear 342 are compactly arranged, and the outside and inside of the planetary gears 343 are respectively meshed with the ring gear 342 and the sun gear 341, with small losses, the gears are always meshed with each other, and the wear is small. At the same time, due to the simple and compact structure, the motion accuracy and reliability are high, thereby extending the service life.

[0109] The gearbox assembly 34 also includes a gearbox body, in which a sun gear 341, a ring gear 342, a plurality of planetary gears 343 and a plurality of connecting pins 344 can be installed, so that the entire gearbox assembly 34 can be installed in any space and has a wide range of application scenarios.

[0110] In addition, combined Figures 10 to 12 As shown, the gearbox assembly 34 also includes a first bearing 345 and a second bearing 346. The first bearing 345 and the second bearing 346 are both sleeved outside the connecting shaft portion 41 and are located on opposite sides of the driven wheel 332. The first bearing 345 and the second bearing 346 are respectively interference fit with the sun gear 341.

[0111] Combination Figures 10 to 12 As shown, the gearbox assembly 34 further includes a third bearing 347 and a fourth bearing 348 , which are spaced apart along the axial direction of the transmission shaft structure 4 , and are assembled with the flange nut 35 by interference fit.

[0112] Optionally, the axis of the input end of the gear box assembly 34 coincides with the axis of the transmission shaft structure 4 .

[0113] Specifically, the input end of the gearbox assembly 34 may be a sun gear 341, and since the driven wheel 332 is sleeved on another part of the sun gear 341 that protrudes from the ring gear 342, and the driven wheel 332 is sleeved on the connecting shaft portion 41, the input end (sun gear 341) of the gearbox assembly 34 is equivalent to being sleeved on the transmission shaft structure 4, so that the axis of the input end of the gearbox assembly 34 coincides with the axis of the transmission shaft structure 4, thereby making the assembly of the sun gear 341 and the driven wheel 332 of the gearbox assembly 34 compact, and correspondingly reducing the space occupied by the entire transmission assembly 33 and the gearbox assembly 34.

[0114] In the related art, a vehicle adopting four-wheel steering usually has a rear-wheel active steering device installed on the rear axle of the vehicle, which mainly includes a drive motor, an input gear, a nut member with a toothed structure, a lead screw and a fork arm assembly. The two ends of the lead screw are respectively connected to the left and right steering knuckle arms of the vehicle through the fork arm assembly, and the nut member is sleeved outside the lead screw. The toothed structure of the nut member is meshed and connected with the input gear. When performing steering operations, the motor shaft of the drive motor can be connected to the input gear to drive the input gear to rotate through the drive motor, and the input gear drives the nut member to rotate. The nut member converts the rotational motion of the input gear into the left and right linear motion of the lead screw, so that the steering knuckle arm is driven to rotate through the lead screw via the fork arm assembly to achieve steering operations of the rear wheels at a certain angle.

[0115] Since the above-mentioned mechanical transmission structure is a parallel axis type, that is, the driving motor and the lead screw are arranged in parallel, and a mechanical transmission mechanism (input gear, nut with a toothed structure) is arranged between the motor and the lead screw to realize power transmission, it has the following disadvantages: 1. The manufacturing and installation accuracy of the input gear is high, and the installation accuracy of the gear also has an important impact on the transmission performance. If it is improperly installed, it may cause the input gear transmission efficiency to decrease or generate noise. 2. High cost: Due to the high manufacturing and installation accuracy requirements for the input gear and nut, the cost of the above-mentioned lead screw nut gear mechanism is relatively high, especially when special materials or processing technology are required, the cost may increase further. 3. When the accuracy of the input gear and nut is low, the vibration and noise are large, which will not only affect the transmission efficiency, but also may cause premature damage to the gear.

[0116] Optionally, combined Figures 13 to 15 As shown, the driving part 2 includes a housing 21 and a stator winding 22, and the stator winding 22 is arranged in the housing 21; the transmission mechanism 3 includes a rotor nut 36 and a magnetic tile 37, and the magnetic tile 37 is coaxial with the rotor nut 36 and fixedly connected, and the stator winding 22 is sleeved on the magnetic tile 37, and the stator winding 22 is used to drive the magnetic tile 37 to drive the rotor nut 36 to rotate;

[0117] The transmission shaft structure 4 includes a screw portion 42 and two connecting shaft portions 41 , the rotor nut 36 is sleeved outside the screw portion 42 , and both ends of the screw portion 42 are respectively connected to the corresponding connecting shaft portions 41 ; the connecting shaft portions 41 are used for sliding cooperation with the limit member 1 .

[0118] Specifically, the outer shell 21 can be a shell structure with a hollow interior, so that the stator winding 22 can be installed in the outer shell 21; the magnetic tile 37 is composed of a permanent magnet, which generates a constant magnetic field and interacts with the magnetic field generated by the stator winding 22 to generate torque. Since the magnetic tile 37 can be fixed to the rotor nut 36 by bonding, it can drive the rotor nut 36 to rotate.

[0119] The magnetic shoe 37 and the rotor nut 36 are coaxially arranged, which means that the magnetic shoe 37 and the rotor nut 36 are coaxially sleeved outside the connecting shaft portion 41 of the transmission shaft structure 4. The magnetic shoe 37 and the rotor nut 36 can together form a motor rotor magnetically connected to the stator winding 22.

[0120] Both ends of the screw portion 42 are respectively connected to the corresponding connecting shaft portions 41 , and the ends of the connecting shaft portions 41 away from the screw portion 42 are respectively connected to the corresponding fork arm assemblies 5 .

[0121] Combination Fig.13 and Fig.14 As shown, the connecting shaft portion 41 may include two connecting shaft portions 41, and the limiting portion 6 may be installed on at least one of the connecting shaft portions 41. For example, a mounting groove 410 is provided on the connecting shaft portion 41, and a portion of the limiting portion 6 is inserted into the mounting groove 410 to achieve a fixed connection between the limiting portion 6 and the connecting shaft portion 41. A limiting groove 111 is provided on the limiting member 1, and the connecting shaft portion 41 and the limiting portion 6 are embedded in the limiting groove 111. The connecting shaft portion 41 and the limiting portion 6 can move axially in the limiting groove 111, but the limiting groove 111 is used to limit the limiting portion 6 and the connecting shaft portion 41 from radially rotating along with the transmission structure.

[0122] Combination Fig.15 As shown, the stator winding 22 may include a stator coil 221 and a coil support 222, wherein the stator coil 221 is wound around the coil support 222. The rotor nut 36 may be sleeved at a middle position of the lead screw portion 42.

[0123] In this optional embodiment, since the stator winding 22 is arranged in the outer shell 21, the stator winding 22 is safely protected by the outer shell 21; when the stator coil 221 of the stator winding 22 is energized, when the current flows through the stator coil 221, the generated magnetic field interacts with the magnetic field of the magnetic tile 37 on the rotor nut 36, so that the magnetic tile 37 can be driven by the stator winding 22 to drive the rotor nut 36 to rotate, and the rotor nut 36 is sleeved on the outside of the screw part 42 to convert the rotational motion of the rotor nut 36 into its own axial movement through the screw part 42, thereby driving the steering knuckle arm to move axially through the screw part 42 via the fork arm assembly 5 to realize the active rotation of the rear wheel.

[0124] Optionally, combined Fig.16 As shown, a plurality of fixing grooves 361 are provided in the circumferential direction of the rotor nut 36 , and the magnetic tile 37 includes a plurality of magnetic tile monomers, and the magnetic tile monomers are installed in the corresponding fixing grooves 361 .

[0125] Specifically, a plurality of fixing grooves 361 may be opened in the circumferential direction of the rotor nut 36, and the number of the fixing grooves 361 is greater than or equal to the number of the magnetic tile units. The magnetic tile units may be installed in the fixing grooves 361 by a fixing method such as bonding to achieve a fixed connection between the two.

[0126] The plurality of fixing grooves 361 of the rotor nut 36 may be equivalent to a hollow structure opened in the circumferential direction of the rotor nut 36 .

[0127] In this optional embodiment, since multiple magnetic tile monomers are respectively installed in the circumferentially corresponding fixing grooves 361 of the rotor nut 36, the magnetic tile monomers can drive the rotor nut 36 to rotate synchronously under the action of the magnetic field of the stator winding 22.

[0128] Optionally, combined Fig.15 As shown, the outer shell 21 includes a motor shell 211 and an end cover 212. The motor shell 211 is a shell structure with a second accommodating cavity inside and an open end. The end cover 212 is arranged at the opening of the motor shell 211; the stator winding 22 is embedded in the second accommodating cavity of the motor shell 211, and the end of the screw part 42 passes through the end cover 212 and is connected to the corresponding connecting shaft part 41.

[0129] Specifically, the housing 21 may include at least one end cover 212. For example, if the motor housing 211 has one end opening, the number of the end cover 212 may be one. If the motor housing 211 has two end openings arranged opposite to each other, the number of the end cover 212 may be two (combined with Fig.15 shown).

[0130] The motor housing 211 is a shell structure with a second accommodating cavity inside and at least one end open. The end cover 212 can be sealed and installed at the opening of the motor housing 211; the two end covers 212 can be fixed to the motor housing 211 as an integral structure through a second fastener. The stator winding 22 can be embedded in the motor housing 211, so the stator winding 22 is fixed by the motor housing 211. The second fastener can be a bolt structure.

[0131] The housing 21 further includes two oil seals 213 , which are spaced apart along the axial direction of the transmission shaft structure 4 and are respectively disposed at the connection between the end cover 212 and the lead screw portion 42 , thereby sealing the interior of the housing 21 .

[0132] The end cover 212 is sealed at the opening of the motor housing 211, so that the stator winding 22, the rotor nut 36 and the magnetic tile 37 can be encapsulated in the motor housing 211; and it is also used to fix the rotor nut 36, combined with Fig.15 As shown, for example, the transmission mechanism 3 also includes a fifth bearing 38 and a sixth bearing 39, wherein the fifth bearing 38 and the sixth bearing 39 can be arranged at intervals along the axial direction of the screw portion 42, and the fifth bearing 38 and the sixth bearing 39 are respectively interference fit with the inner walls of the axial ends of the rotor nut 36, so that the two end covers 212 not only provide support positions for the fifth bearing 38 and the sixth bearing 39 at both ends of the rotor nut 36 to support the rotational movement of the rotor nut 36, but also ensure the rotation stability of the rotor nut 36.

[0133] A vehicle provided by an embodiment of the present invention comprises rear wheels and the vehicle rear wheel active steering device as described above.

[0134] Specifically, the vehicle may include two rear wheels, such as a left rear wheel and a right rear wheel, and the ends of the two wishbone assemblies 5 in the vehicle's rear wheel active steering device away from the transmission shaft structure 4 may be directly connected to the left rear wheel and the right rear wheel respectively.

[0135] Alternatively, the vehicle further comprises two steering knuckle arms, which are arranged at one end of the fork arm assembly 5 away from the transmission shaft structure 4; the steering knuckle arms can serve as a connecting structure between the vehicle's rear wheel active steering device and the rear wheels.

[0136] The vehicle further comprises a chassis and a limiting member 1, wherein the limiting member 1 can be fixedly mounted on the chassis, wherein the limiting member 1 can be fixedly mounted on the chassis by welding, bolt connection or the like.

[0137] Combination Figure 4 , Fig. 9 and Fig.13As shown, the fork arm assembly 5 includes a fork arm connecting shaft 51 and a fork arm body 52, wherein one end of the fork arm connecting shaft 51 is fixedly connected to the end of the connecting shaft portion 41 or the screw portion 42 in the transmission shaft structure 4 by, for example, a threaded connection; the other end of the fork arm connecting shaft 51 is connected to the fork arm body 52 by, for example, a ball joint, a threaded connection, etc.; the end of the fork arm body 52 away from the fork arm connecting shaft 51 can be connected to the wheel hub of the rear wheel of the vehicle through a steering knuckle arm.

[0138] Among them, one fork arm assembly is connected to the left rear wheel through a steering knuckle arm, and the other fork arm assembly is connected to the right rear wheel through another steering knuckle arm.

[0139] The beneficial effects of the vehicle of this embodiment relative to the prior art are the same as those of the above-mentioned vehicle rear wheel active steering device, which will not be described in detail here.

[0140] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A vehicle rear wheel active steering device, characterized in that: The vehicle comprises a driving unit (2), a transmission mechanism (3), a transmission shaft structure (4) and two fork arm assemblies (5), wherein the two axial ends of the transmission shaft structure (4) are respectively connected to the corresponding fork arm assemblies (5), and the ends of the two fork arm assemblies (5) away from the transmission shaft structure (4) are respectively connected to the two corresponding rear wheels of the vehicle; the driving unit (2) is connected to the transmission mechanism (3), the transmission shaft structure (4) is connected to the transmission mechanism (3), and the transmission shaft structure (4) is used to convert the rotational motion of the transmission mechanism (3) into its own axial motion; The transmission shaft structure (4) is used for sliding cooperation with a limiting member (1) arranged on the chassis, and the limiting member (1) is used for limiting the rotation of the transmission shaft structure (4).

2. The vehicle rear wheel active steering device according to claim 1, characterized in that: The transmission shaft structure (4) is provided with a limiting portion (6), the limiting member (1) is provided with a limiting groove (111), the transmission shaft structure (4) and the limiting portion (6) are arranged in the limiting groove (111), and the limiting portion (6) is slidably matched with the inner wall of the limiting groove (111); when the transmission shaft structure (4) has a tendency to rotate, the limiting portion (6) abuts against the inner wall of the limiting groove (111) to limit the rotation of the transmission shaft structure (4).

3. The vehicle rear wheel active steering device according to claim 2, characterized in that: The transmission shaft structure (4) is provided with two installation grooves (410) which are symmetrically distributed along its radial direction, and parts of the two limiting portions (6) are respectively inserted into the corresponding two installation grooves (410), and the end surface of the limiting portion (6) away from the transmission shaft structure (4) is slidably matched with the inner side wall of the limiting groove (111).

4. The vehicle rear wheel active steering device according to claim 1, characterized in that: The transmission mechanism (3) comprises a turbine (31) and a retaining frame (32); the driving portion (2) is drivingly connected to the turbine (31); the turbine (31) has a helical tooth portion (311) in the circumferential direction; one end of the retaining frame (32) is connected to the transmission shaft structure (4); one end of the retaining frame (32) away from the transmission shaft structure (4) penetrates into the helical tooth portion (311), and the side wall of the helical tooth portion (311) abuts against the retaining frame (32); the retaining frame (32) is used to convert the rotational motion of the turbine (31) into the axial movement of the transmission shaft structure (4).

5. The vehicle rear wheel active steering device according to claim 4, characterized in that: The retaining frame (32) comprises a bearing seat (321) and a connecting frame (322); the bearing seat (321) is sleeved on the transmission shaft structure (4); the connecting frame (322) is connected to an end of the bearing seat (321) away from the transmission shaft structure (4); and the end of the connecting frame (322) away from the bearing seat (321) is deeply inserted into the spiral tooth portion (311).

6. The vehicle rear wheel active steering device according to claim 5, characterized in that: The retaining frame (32) also includes a rolling element (323), and a first accommodating cavity is arranged between one end of the bearing seat (321) away from the transmission shaft structure (4) and the connecting frame (322), a part of the rolling element (323) is located in the first accommodating cavity, and another part of the rolling element (323) is located in the spiral tooth portion (311), and the two are connected in a rolling manner.

7. The vehicle rear wheel active steering device according to claim 1, characterized in that: The transmission mechanism (3) comprises a transmission assembly (33), a gear box assembly (34) and a flange nut (35); the transmission shaft structure (4) comprises a connecting shaft portion (41) and a screw portion (42); the driving portion (2) is connected to the transmission assembly (33); the input end of the gear box assembly (34) is connected to the transmission assembly (33) in a transmission manner; the output end of the gear box assembly (34) is connected to the flange nut (35); the flange nut (35) is sleeved outside the screw portion (42); one end of the screw portion (42) is connected to one fork arm assembly (5); and the other end of the screw portion (42) is connected to another fork arm assembly (5) via the connecting shaft portion (41); The connecting shaft portion (41) is used for sliding cooperation with the limiting member (1).

8. The vehicle rear wheel active steering device according to claim 7, characterized in that: The transmission assembly (33) comprises a driving wheel (331), a driven wheel (332) and a transmission component (333); the driving portion (2) is connected to the driving wheel (331) and is used to drive the driving wheel (331) to rotate; the driven wheel (332) is sleeved on the connecting shaft (41) and is transmission-connected to the gear box assembly (34); the driving wheel (331) and the driven wheel (332) are connected via the transmission component (333).

9. The vehicle rear wheel active steering device according to claim 8, characterized in that: The gearbox assembly (34) comprises a sun gear (341), a ring gear (342), a plurality of planetary gears (343) and a plurality of connecting pins (344); the ring gear (342) has internal teeth; the plurality of planetary gears (343) are arranged in the ring gear (342) in an annular manner and are respectively meshed with the internal teeth; a portion of the sun gear (341) is arranged in the ring gear (342) and meshed with the planetary gears (343); another portion of the sun gear (341) is fixedly connected to the driven gear (332); One end of the connecting pin (344) is connected to the corresponding planetary gear (343), and the other end of the connecting pin (344) is fixedly connected to the flange nut (35). The planetary gear (343) is used to drive the flange nut (35) to rotate through the connecting pin (344).

10. The vehicle rear wheel active steering device according to claim 7, characterized in that: The axis of the input end of the gear box assembly (34) coincides with the axis of the transmission shaft structure (4).

11. The vehicle rear wheel active steering device according to claim 1, characterized in that: The driving part (2) comprises a housing (21) and a stator winding (22), wherein the stator winding (22) is arranged in the housing (21); the transmission mechanism (3) comprises a rotor nut (36) and a magnetic tile (37), wherein the magnetic tile (37) is coaxial with and fixedly connected to the rotor nut (36), the stator winding (22) is sleeved on the magnetic tile (37), and the stator winding (22) is used to drive the magnetic tile (37) to drive the rotor nut (36) to rotate; The transmission shaft structure (4) comprises a screw portion (42) and two connecting shaft portions (41); the rotor nut (36) is sleeved outside the screw portion (42); two ends of the screw portion (42) are respectively connected to corresponding connecting shaft portions (41); and the connecting shaft portions (41) are used for sliding cooperation with the limiting member (1).

12. The vehicle rear wheel active steering device according to claim 11, characterized in that: The rotor nut (36) is provided with a plurality of fixing grooves (361) in the circumferential direction, and the magnetic tile (37) comprises a plurality of magnetic tile monomers, and the magnetic tile monomers are installed in corresponding fixing grooves (361).

13. The vehicle rear wheel active steering device according to claim 11, characterized in that: The outer shell (21) comprises a motor shell (211) and an end cover (212); the motor shell (211) is a shell structure having a second accommodating cavity provided therein and an end opening; the end cover (212) is arranged at the opening of the motor shell (211); the stator winding (22) is embedded in the second accommodating cavity of the motor shell (211); the end of the lead screw portion (42) passes through the end cover (212) and is connected to the corresponding connecting shaft portion (41).

14. A vehicle, characterized in that: The vehicle comprises a rear wheel and a rear wheel active steering device as claimed in any one of claims 1 to 13.

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