Rear wheel steering gear assembly and vehicle having the same

Abstract

The application provides a rear wheel steering gear assembly and a vehicle with the same, the rear wheel steering gear assembly comprising: a shell; a screw spindle arranged inside the shell; a screw nut connected with the shell and located outside the screw spindle; and a planetary roller connected with the screw spindle and the screw nut; wherein both ends of the screw nut in the axial direction are provided with flange seats, first axial bearings are arranged between the two ends of the screw nut in the axial direction and the inner side walls of the corresponding flange seats, a pre-tightening washer is arranged between the outer side wall of at least one of the two flange seats and the shell, a second axial bearing is arranged between the outer side wall of the flange seat and the inner side wall of the pre-tightening washer, the pre-tightening washer is made of an elastic material, and the surface of at least one of the inner side wall of the pre-tightening washer and the outer side wall of the pre-tightening washer is provided with a corrugated structure. The application effectively solves the problem of complex structure of the rear wheel steering gear in the prior art.

Description

Technical Field

[0001] This invention relates to the field of rear-wheel steering design technology, and more specifically, to a rear-wheel steering assembly and a vehicle having the same. Background Technology

[0002] Currently, the core component of rear wheel steering systems includes the lead screw, which mainly comes in two types: trapezoidal nut lead screws and planetary roller lead screws. Trapezoidal nut lead screws have a relatively simple structure, but suffer from low transmission efficiency, only about 25%. Planetary roller lead screws have higher transmission efficiency, typically above 60%. However, this high efficiency leads to the inability to achieve mechanical self-locking, usually requiring the addition of a preload device or an external friction structure to control the transmission efficiency below 50% to achieve mechanical self-locking. Existing preload devices significantly increase the structural complexity of planetary roller lead screw solutions, resulting in high cost, insufficient load-bearing capacity, and susceptibility to failure under heavy load impacts. Summary of the Invention

[0003] The main objective of this invention is to provide a rear wheel steering assembly and a vehicle having the same, in order to solve the problem of the complex structure of the rear wheel steering system in the prior art.

[0004] To achieve the above objectives, according to one aspect of the present invention, a rear wheel steering assembly is provided, comprising: a housing; a lead screw spindle disposed inside the housing; a lead screw nut connected to the housing and located outside the lead screw spindle; planetary rollers located between the lead screw spindle and the lead screw nut, and connected to both the lead screw spindle and the lead screw nut; wherein, flange seats are provided at both ends of the lead screw nut along its axial direction, the two flange seats are arranged opposite to each other and respectively connected to the axial ends of the planetary rollers, both flange seats are connected to a drive pulley, a first axial bearing is provided between the two axial ends of the lead screw nut and the inner sidewall of the corresponding flange seat, a preload washer is provided between the outer sidewall of at least one of the two flange seats and the housing, a second axial bearing is provided between the outer sidewall of the flange seat and the inner sidewall of the preload washer, the preload washer is made of an elastic material, and the surfaces of at least one of the inner sidewall and the outer sidewall of the preload washer are provided with a corrugated structure.

[0005] Furthermore, the first axial bearing and the second axial bearing are coaxially arranged, and the central axis of the first axial bearing is parallel to the central axis of the lead screw spindle.

[0006] Furthermore, the housing includes two opposing first housings and second housings, through which the lead screw spindle passes. The first housing and second housing enclose a mounting cavity, where the lead screw nut and planetary rollers are located. The rear wheel steering assembly also includes a sleeve disposed within the mounting cavity, located inside and connected to the drive pulley. The rear wheel steering assembly also includes a motor connected to the outer surface of the first housing, which is connected to the drive pulley. The axial ends of the sleeve are connected to two flange seats, and a preload washer is provided between the outer wall of the flange seat closest to the second housing and the housing.

[0007] Furthermore, a radial bearing assembly is provided between one end of the sleeve and the first housing, and another radial bearing assembly is provided between the other end of the sleeve and the second housing.

[0008] Furthermore, the radial bearing assembly includes at least one radial bearing, the type of which includes needle roller bearings and ball bearings. The inner rings of both radial bearings are interference-fitted to the outer surface of the sleeve. The outer ring of one radial bearing is interference-fitted to the inner surface of the first housing, and the outer ring of the other radial bearing is interference-fitted to the inner surface of the second housing.

[0009] Furthermore, the lead screw spindle is provided with two cages, which are located at both ends of the planetary rollers and connected to both ends of the planetary rollers. The two cages are correspondingly provided and connected to the two flange seats.

[0010] Furthermore, the preload washer includes: a mating portion, a corrugated structure disposed on the side of the mating portion facing the second housing, and an annular groove disposed on the side of the mating portion facing the first housing, the annular groove being used to position the outer circumferential surface of the second axial bearing.

[0011] Furthermore, the outer diameter of the lead screw spindle is 20mm-40mm, and the outer surface of the lead screw spindle has a threaded lift structure with a lead range of 0.8mm-2.0mm.

[0012] Furthermore, two anti-rotation shaft sections are respectively provided at both ends of the lead screw spindle. The rear wheel steering assembly also includes an anti-rotation structure. The two anti-rotation shaft sections are connected to the two anti-rotation structures respectively. The two anti-rotation structures have the same structure. The anti-rotation structure includes: an anti-rotation inner skeleton, which is connected to the anti-rotation shaft section; and an anti-rotation outer ring, the outer wall of which fits with the anti-rotation groove opened on the housing, and the inner wall of which fits with the anti-rotation inner skeleton.

[0013] According to another aspect of the present invention, a vehicle is provided, including a rear wheel steering assembly, the rear wheel steering assembly being the aforementioned rear wheel steering assembly.

[0014] By applying the technical solution of this invention, mechanical self-locking and axial preload of the rear wheel steering gear can be achieved through a first axial bearing, a second axial bearing, and a preload washer with a corrugated structure. This eliminates the need for axial preload devices or additional friction structures found in existing technologies, thus simplifying the structure of the rear wheel steering gear assembly. The technical solution of this application effectively solves the problem of complex structures in existing rear wheel steering gears. Attached Figure Description

[0015] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0016] Figure 1 A schematic diagram of a first embodiment of the rear wheel steering assembly according to the present invention is shown;

[0017] Figure 2 A schematic diagram of a second embodiment of the rear wheel steering assembly according to the present invention is shown;

[0018] Figure 3 A schematic diagram of a third embodiment of the rear wheel steering assembly according to the present invention is shown;

[0019] Figure 4 A schematic diagram of a fourth embodiment of the rear wheel steering assembly according to the present invention is shown;

[0020] Figure 5 A schematic diagram of a fifth embodiment of the rear wheel steering assembly according to the present invention is shown.

[0021] The above figures include the following reference numerals:

[0022] 2. First housing; 3. Second housing; 5. Position sensor; 6. Motor; 7. Snap ring; 9. Fork; 11. Lead screw spindle; 111. Solid part; 112. Hollow part; 113. Anti-rotation shaft section; 114. Threaded connection part; 12. Planetary roller; 121. First concave part; 122. Protruding part; 123. Second concave part; 13. Lead screw nut; 141. Sleeve; 142. Flange seat; 143. Cage; 15. Drive pulley; 16. Radial bearing assembly; 17. First axial bearing; 18. Second axial bearing; 19. Preload washer; 191. Annular groove; 192. Fitting part; 193. Corrugated structure; 21. Anti-rotation structure; 211. Anti-rotation inner skeleton; 212. Anti-rotation outer ring; 213. Anti-rotation groove. Detailed Implementation

[0023] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0024] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0025] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0026] Exemplary embodiments according to this application will now be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. It should be understood that these embodiments are provided so that the disclosure of this application is thorough and complete, and that the concept of these exemplary embodiments is fully conveyed to those skilled in the art. In the drawings, for clarity, the thickness of layers and regions may be exaggerated, and the same reference numerals are used to denote the same devices, and therefore their description will be omitted.

[0027] The rear wheel steering assembly is a device used to drive the rear wheels to make small turns, usually in conjunction with the front wheel steering. The rear wheel steering assembly actively actuates according to the vehicle speed and the front wheel turning angle to achieve the turning angle of the rear wheels, thereby improving the overall vehicle performance.

[0028] The prior art (CN113272577A) discloses a rear wheel steering assembly with a split-type nut for the planetary rollers. Axial preload is achieved through a nut tensioning element, reducing system efficiency and achieving mechanical self-locking, resulting in a relatively complex structure. Furthermore, the four bearings arranged axially on the inner and outer sides of the planetary roller screw cage are of two different specifications. The two bearings located on the outer side of the axial direction require custom-made planar thrust bearings with an offset mounting structure, allowing friction to occur while the bearing rotates, further reducing efficiency and achieving mechanical self-locking. This design suffers from poor generalization, and the entire system requires adjusting rings to achieve axial preload between the four bearings and the planetary rollers, eliminating axial clearance. Multiple adjusting rings are typically needed, with different combinations selected through adjustment to accommodate axial clearance, thus resulting in a complex structure. The manufacturing process of the above solution is relatively complex, leading to a bulky and complex overall structure. The entire planetary roller screw and bearing assembly is directly connected to the housing, lacking necessary radial support structure design, which may lead to large radial deformation near the screw, negatively impacting overall performance.

[0029] The prior art (CN114450505A) discloses a planetary roller screw transmission device, which transmits axial and radial loads through axially tilted roller bearings. However, this solution has limited overall load-bearing capacity. Under large axial loads, the tilted roller bearings cause uneven force distribution among the internal components of the planetary roller screw, leading to unpredictable off-center loading and affecting overall strength and durability. Furthermore, this solution uses the rotation axis of the rollers in the tilted bearing to increase friction according to the load, thereby achieving mechanical self-locking. However, this type of bearing requires special customization, resulting in additional cost. Therefore, the challenge lies in developing a novel steering mechanism that achieves mechanical self-locking without requiring customized bearings or additional axial tensioning devices, thus reducing cost and structural complexity.

[0030] In addition, the current rear wheel steering rack assist capability is usually ≤15kN@10mm / s. At low temperatures, the system performance will be greatly reduced (to about 10kN@10mm / s), which cannot meet the requirement that the whole vehicle still has a fast response speed under heavy load.

[0031] Combination Figures 1 to 5 As shown, according to a specific embodiment of this application, a rear wheel steering assembly is provided.

[0032] The rear wheel steering assembly includes: a housing; a lead screw spindle 11, which is disposed inside the housing; a lead screw nut 13, which is connected to the housing and located outside the lead screw spindle 11; and planetary rollers 12, which are located between the lead screw spindle 11 and the lead screw nut 13 and are connected to both the lead screw spindle 11 and the lead screw nut 13; wherein, flange seats 142 are provided at both ends in the axial direction of the lead screw nut 13, and the two flange seats 142 are arranged opposite to each other and respectively connected to the two ends in the axial direction of the planetary rollers 12. Both flange seats 142 are connected to the drive pulley 15. A first axial bearing 17 is provided between the two axial ends of the lead screw nut 13 and the inner sidewall of the corresponding flange seat 142. A preload washer 19 is provided between the outer sidewall of at least one of the two flange seats 142 and the housing. A second axial bearing 18 is provided between the outer sidewall of the flange seat 142 and the inner sidewall of the preload washer 19. The preload washer 19 is made of elastic material. The surface of at least one of the inner sidewall and the outer sidewall of the preload washer 19 is provided with a corrugated structure 193.

[0033] By applying the technical solution of this invention, mechanical self-locking and axial preload of the rear wheel steering gear can be achieved through a first axial bearing, a second axial bearing, and a preload washer with a corrugated structure. This eliminates the need for axial preload devices or additional friction structures found in existing technologies, thus simplifying the structure of the rear wheel steering gear assembly. The technical solution of this application effectively solves the problem of complex structures in existing rear wheel steering gears.

[0034] In fact, the lead screw of the rear wheel steering assembly adopts a planetary roller type. Although its high transmission efficiency makes self-locking difficult, in a planetary roller rear wheel steering assembly with a small lead of threaded lift structure, self-locking can be achieved using the lead screw spindle 11. That is to say, by reasonably designing the outer diameter of the lead screw spindle 11 and the lead of the threaded lift structure, self-locking can be achieved without customizing other types of bearings. At the same time, the preload washer 19 made of elastic material also achieves the function of eliminating axial clearance, thereby simplifying the internal structure of the steering gear. Setting a smaller lead will lead to a decrease in response speed, which can be overcome by reducing the reduction ratio.

[0035] Furthermore, the first axial bearing 17 and the second axial bearing 18 are coaxially arranged, and the central axis of the first axial bearing 17 is parallel to the central axis of the lead screw spindle 11.

[0036] like Figure 1 and Figure 4As shown, the rear wheel steering housing is fixed to the subframe or frame with bolts. The motor 6 is fixed to the housing and drives the drive pulley 15 of the planetary roller screw via a synchronous belt. The planetary roller screw assembly acts as a force transmission device, converting the rotational motion of the drive pulley 15 into the linear motion of the screw, thereby achieving active steering of the rear wheels. Overall, the planetary roller screw passes through the housing and is coaxially arranged with it. Both ends of the screw are bolted to the fork 9 via connecting rods. One side of the dust cover is fixed to the housing via retaining rings 7, and the other side is also fixed to the fork 9 via retaining rings 7, achieving overall sealing and dust prevention. Driven by the motor 6, the screw spindle 11 can move left and right relative to the housing along its own axis, thereby pushing the fork to move left and right relative to the housing, achieving the steering function. Figure 4 The image also shows position sensor 5.

[0037] Furthermore, the housing includes two opposing first housings 2 and second housings 3. The lead screw spindle 11 passes through the first housing 2 and the second housing 3. The first housing 2 and the second housing 3 enclose and form a mounting cavity. The lead screw nut 13 and the planetary roller 12 are both located in the mounting cavity. The rear wheel steering assembly also includes a sleeve 141 disposed in the mounting cavity. The sleeve 141 is located inside the drive pulley 15 and connected to the drive pulley 15. The rear wheel steering assembly also includes a motor 6 connected to the outer surface of the first housing 2. The motor 6 is connected to the drive pulley 15. The axial ends of the sleeve 141 are respectively connected to two flange seats 142. A preload washer 19 is disposed between the outer side wall of the flange seat 142 closest to the second housing 3 and the housing.

[0038] By adopting the technical solution of this application, mechanical self-locking is achieved through the design of parameters such as the outer diameter and lead of the planetary roller screw itself. (That is, the drive pulley 15 drives the cage 143 to rotate, which can realize the linear motion of the screw spindle 11. When an axial load is applied to the screw spindle 11, the cage 143 and the nut cannot rotate.) This avoids the use of additional preload mechanisms or special high-friction bearings, resulting in a simpler structure. By arranging load-bearing bearings in the radial and axial directions respectively, the load-bearing capacity and stability of the entire system can be improved, and the four radial bearings can be designed as universal parts, reducing costs. By designing the material, shape, and stiffness characteristics of the preload washer, and relying on the dimensional interference fit and stiffness design, the axial preload of the screw is achieved without additional adjustment, eliminating axial clearance. This avoids the need for additional preload adjustment devices, simplifies the assembly process, improves manufacturing efficiency, and reduces costs.

[0039] Furthermore, a radial bearing assembly 16 is provided between one end of the sleeve 141 and the first housing 2, and another radial bearing assembly 16 is provided between the other end of the sleeve 141 and the second housing 3.

[0040] In an optional embodiment, the planetary roller screw drive includes a screw spindle 11. The outer diameter of the spindle screw is 20mm-40mm. The screw has a threaded lift structure with a lead range of 0.8-2.0mm. The screw nut 13 is coaxially arranged with the screw spindle 11, and the planetary rollers 12 are located between the screw spindle 11 and the screw nut 13, evenly distributed along the circumference, with a quantity of 8-20. One side of the cage 143 has a recessed structure that mates with the end of the planetary rollers 12 to ensure that the planetary rollers 12 are in the correct position and to prevent tilting. The other side of the cage has a raised groove that engages with the flange seat 142. The flange seat 142 is engaged and fixed with the sleeve 141. The sleeve 141 is interference-fitted with the drive pulley 15. When the drive pulley is driven to rotate by the motor, it can synchronously drive the sleeve 141, the flange seat 142, and the cage 143 to rotate. The rotation of the cage 143 will cause the planetary rollers 12 to rotate around the lead screw spindle 11.

[0041] Furthermore, the radial bearing assembly 16 includes at least one radial bearing, the type of which includes needle roller bearings and ball bearings. The inner rings of both radial bearings are interference-fitted to the outer surface of the sleeve 141. The outer ring of one radial bearing is interference-fitted to the inner surface of the first housing 2, and the outer ring of the other radial bearing is interference-fitted to the inner surface of the second housing 3.

[0042] The independent radial bearing assembly 16 can be either a needle roller bearing or a ball bearing, and there can be two of them. The inner ring of the bearing is interference-fitted to both ends of the sleeve 141, and the outer ring is interference-fitted to the first housing 2 or the second housing 3. This provides radial support and has a strong ability to withstand radial loads.

[0043] like Figure 1 As shown, the contact surface between the preload washer 19 and the second housing 3 is provided with a corrugated structure 193. This corrugated structure can be provided on one side or both sides. The corrugated structure design allows adjustment of the dimensions of the preload washer's contact portion 192, thereby adjusting the washer's axial stiffness and ensuring the axial preload of the planetary roller screw is within a set range, eliminating backlash. The preload washer is made of plastic, possessing a certain degree of compressive deformation capability and good load-bearing capacity. The preload washer has a fixed size; once designed, no additional adjustments are needed, and direct assembly achieves the preload effect.

[0044] Furthermore, the lead screw spindle 11 is provided with two cages 143, which are located at both ends of the planetary roller 12 respectively. The two cages 143 are connected to both ends of the planetary roller 12 respectively, and the two cages 143 are correspondingly provided and connected to the two flange seats 142.

[0045] Furthermore, the outer diameter of the lead screw spindle 11 is 20mm-40mm, and the outer surface of the lead screw spindle 11 has a threaded lift structure with a lead range of 0.8mm-2.0mm.

[0046] Furthermore, the preload washer 19 includes: a fitting portion 192, a corrugated structure 193 disposed on the side of the fitting portion 192 facing the second housing 3, and an annular groove 191 disposed on the side of the fitting portion 192 facing the first housing 2, the annular groove 191 being used to position the outer circumferential surface of the second axial bearing 18.

[0047] Four axial planar bearings (i.e., two first axial bearings 17 and two second axial bearings 18) are arranged coaxially with the lead screw spindle 11. The first axial bearings 17 are located on the outer side of the lead screw nut 13, and their outer sides are fitted against the flange seat 142. The second axial bearings 18 are located on the outer side of the flange seat 142. One end of the second axial bearing 18 is fitted against the first housing 2 and placed within the annular groove of the first housing 2. The annular groove of the first housing 2 serves to position the second axial bearing 18 circumferentially. The other end of the second axial bearing 18 is fitted against the preload washer 19 and placed within it. Within the annular groove of the preload washer 19, the preload washer 19 is axially fitted with the second housing 3 and placed within the annular groove of the second housing 3. The annular groove of the second housing 3 is used to position the preload washer 19 in the circumferential direction. The annular groove 191 of the preload washer 19 is used to position the second axial bearing 18 at the other end in the circumferential direction. The three annular grooves on the first housing 2, the second housing 3, and the preload washer 19 ensure the coaxiality of the bearing, the preload washer, and the lead screw spindle. In addition, the four planar bearing structures can be a universal structure, which helps to reduce the types of parts and reduce costs.

[0048] Furthermore, the axis of the second axial bearing 18, the axis of the preload washer 19, and the axis of the lead screw spindle 11 are parallel.

[0049] Furthermore, two anti-rotation shaft sections 113 are respectively provided at both ends of the lead screw spindle 11. The rear wheel steering assembly also includes an anti-rotation structure 21. The two anti-rotation shaft sections 113 are connected to the two anti-rotation structures 21 respectively. The two anti-rotation structures 21 have the same structure. The anti-rotation structure 21 includes: an anti-rotation inner skeleton 211, which is connected to the anti-rotation shaft section 113; and an anti-rotation outer ring 212, the outer wall of which fits with the anti-rotation groove 213 opened on the housing, and the inner wall of which fits with the anti-rotation inner skeleton 211.

[0050] In other words, the anti-rotation structure 21 consists of an anti-rotation inner skeleton 211, an anti-rotation outer ring 212, and an anti-rotation groove 213. The anti-rotation inner skeleton 211 is coaxially arranged with the anti-rotation shaft section 113 of the lead screw spindle, and is interference-fitted in a polygonal form. The anti-rotation outer ring 212 is placed in the anti-rotation groove of the housing. The contact surface between the anti-rotation outer ring 212 and the anti-rotation groove of the housing is a planar joint or an arc-shaped structure, with clearance fit on the left and right sides. Grooves are provided on both sides of the anti-rotation outer ring 212 for storing grease. The anti-rotation structure can counteract the rotational torque on the lead screw spindle and prevent the lead screw spindle from rotating excessively. The anti-rotation shaft section 113 and the threaded connection part 114 ( Figure 2 (As shown in the image) connection.

[0051] Existing technical solutions pay little attention to NVH noise issues during the operation of the rear wheel steering assembly, especially the noise problems caused by internal structural damage or wear after durability. Furthermore, the anti-rotation inner frame 211 is made of metal, while the anti-rotation outer ring 212 is made of plastic.

[0052] The anti-rotation inner frame 211 is made of metal, which has good strength, while the anti-rotation outer ring 212 is made of plastic. When the lead screw spindle moves linearly, there will be relative movement between the outer ring of the anti-rotation structure and the housing. The plastic material can significantly improve the noise problem.

[0053] Alternatively, the lead screw spindle can be a solid structure. Figure 2 The solid part 111 shown in the figure can also be a hollow structure. Figure 2 The hollow section 112 is shown in the figure. The hollow structure design can effectively reduce weight.

[0054] The middle section of the planetary roller is a protrusion 122, which is threadedly engaged with the lead screw spindle on one side and has a clearance fit with the lead screw nut on the other side. The two ends of the planetary roller are a first concave part 121 and a second concave part 123, which have a clearance fit with the lead screw spindle and are threadedly engaged with the lead screw nut.

[0055] According to another aspect of the present invention, a vehicle is provided, including a rear wheel steering assembly, the rear wheel steering assembly being the aforementioned rear wheel steering assembly.

[0056] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0057] 1. The existing system has limited load-bearing capacity, with power assist typically ≤15kN. At low temperatures, the system performance drops significantly to approximately 10kN, failing to meet the vehicle's requirement for a fast response speed under heavy loads. In contrast, the rear-wheel steering assembly system proposed in this application has a strong load-bearing capacity of up to 25kN, and its power assist can still reach 15kN even at -40℃.

[0058] 2. In the prior art, the planetary roller screw structure used in the rear wheel steering system is relatively complex, and usually requires additional design of preload mechanism and addition of axial preload device, etc. The solution provided in this application has a relatively simple structure. Preload is achieved by reasonable matching of screw outer diameter and lead and reasonable interference design. No additional adjustment mechanism is required. The universal design of the four axial bearings facilitates processing and manufacturing and reduces costs.

[0059] 3. Existing technologies, due to their complex internal structures, typically suffer from limited load-bearing capacity, susceptibility to damage during durability, and the occurrence of noise and abnormal sounds. This application utilizes axial and radial bearings to bear and transmit loads separately, resulting in a system with strong load-bearing capacity, high axial stiffness, and excellent NVH performance. In particular, after durability, the system exhibits minimal wear and no noise issues.

[0060] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0061] In addition to the above, it should be noted that the terms "one embodiment," "another embodiment," and "embodiment" used in this specification refer to specific features, structures, or characteristics described in connection with that embodiment, which are included in at least one embodiment described in the general description of this application. The appearance of the same expression in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a specific feature, structure, or characteristic is described in connection with any embodiment, the intention is to suggest that implementing such a feature, structure, or characteristic in conjunction with other embodiments also falls within the scope of this invention.

[0062] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0063] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A rear wheel steerer assembly, characterized by, The application relates to a rear wheel steering gear assembly. The rear wheel steering gear assembly comprises a housing, a screw spindle (11) arranged inside the housing, a screw nut (13) connected with the housing and located outside the screw spindle (11), and a planetary roller (12) located between the screw spindle (11) and the screw nut (13) and connected with the screw spindle (11) and the screw nut (13). The screw nut (13) is provided with flange seats (142) at both ends in the axial direction, the two flange seats (142) are oppositely arranged and connected with the axial ends of the planetary roller (12), the two flange seats (142) are connected with driving pulleys (15), first axial bearings (17) are arranged between the two end portions of the screw nut (13) in the axial direction and the inner side walls of the corresponding flange seats (142), a pre-tightening washer (19) is arranged between the outer side wall of at least one of the two flange seats (142) and the housing, a second axial bearing (18) is arranged between the outer side wall of the flange seat (142) and the inner side wall of the pre-tightening washer (19), the pre-tightening washer (19) is made of elastic material, and a corrugated structure (193) is arranged on the surface of at least one of the inner side wall and the outer side wall of the pre-tightening washer (19). The housing comprises oppositely arranged first and second housings (2 and 3), the first and second housings (2 and 3) surround to form a mounting cavity, the rear wheel steering gear assembly further comprises a sleeve (141) arranged in the mounting cavity, one radial bearing set (16) is arranged between one end of the sleeve (141) and the first housing (2), and another radial bearing set (16) is arranged between the other end of the sleeve (141) and the second housing (3). The pre-tightening washer (19) comprises a fitting portion (192), the corrugated structure (193) is arranged on the side of the fitting portion (192) facing the second housing (3), an annular groove (191) is arranged on the side of the fitting portion (192) facing the first housing (2), and the annular groove (191) is used for positioning the outer circumferential surface of the second axial bearing (18). The first axial bearing (17) and the second axial bearing (18) are coaxially arranged, and the central axis of the first axial bearing (17) is parallel to the central axis of the screw spindle (11). ​ ​ 2. The rear wheel steerer assembly of claim 1, wherein, ​ 3. The rear wheel steerer assembly of claim 1, wherein, The lead screw spindle (11) passes through the first housing (2) and the second housing (3), the lead screw nut (13) and the planetary roller (12) are located in the mounting cavity, the sleeve (141) is located inside the drive pulley (15) and connected with the drive pulley (15), the rear wheel steering gear assembly further comprises a motor (6) connected with the outer surface of the first housing (2), the motor (6) is connected with the drive pulley (15), the axial both ends of the sleeve (141) are connected with two flange seats (142) respectively, and the outer side wall of one of the two flange seats (142) close to the second housing (3) is provided with the pre-tightening washer (19) between the housing.

4. The rear wheel steerer assembly of claim 1, wherein, The radial bearing group (16) comprises at least one radial bearing, the type of the radial bearing comprises a needle bearing and a ball bearing, the inner rings of the two radial bearings are interference connected with the outer surface of the sleeve (141), the outer ring of one radial bearing is interference connected with the inner surface of the first housing (2), and the outer ring of the other radial bearing is interference connected with the inner surface of the second housing (3).

5. The rear wheel steerer assembly of claim 3, wherein, The lead screw spindle (11) is provided with two retainer cages (143), the two retainer cages (143) are located at the two ends of the planetary roller (12) respectively, the two retainer cages (143) are connected with the two ends of the planetary roller (12) respectively, and the two retainer cages (143) are correspondingly provided and connected with the two flange seats (142).

6. The rear wheel steerer assembly of any one of claims 1-5, wherein, The outer diameter of the lead screw spindle (11) is 20mm-40mm, the outer surface of the lead screw spindle (11) is provided with a threaded pitch structure, and the lead range of the threaded pitch structure is 0.8mm-2.0mm.

7. The rear wheel steerer assembly of claim 1, wherein, The axial both ends of the lead screw spindle (11) are respectively provided with two anti-rotation shaft sections (113), the rear wheel steering gear assembly further comprises an anti-rotation structure (21), the two anti-rotation shaft sections (113) are connected with the two anti-rotation structures (21) correspondingly, the two anti-rotation structures (21) are the same in structure, and the anti-rotation structure (21) comprises: An anti-rotation inner framework (211) connected with the anti-rotation shaft section (113); An anti-rotation outer ring (212), the outer wall of the anti-rotation outer ring (212) is attached to the anti-rotation groove (213) formed in the housing, and the inner wall of the anti-rotation outer ring (212) is attached to the anti-rotation inner framework (211).

8. A vehicle comprising a rear wheel steerer assembly, characterized by, The rear wheel steering gear assembly is the rear wheel steering gear assembly of any one of claims 1 to 7.

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