Self-adaptive alignment gear shifting structure, transmission and rear axle assembly

Abstract

The utility model discloses a self-adaptive counterpoint gear shifting structure, a transmission and a rear axle assembly, which are characterized in that an active anti-impact surface, a combination tooth first helical surface and a combination tooth second helical surface are designed on a combination tooth, and a passive anti-impact surface, a combination groove first helical surface and a combination groove second helical surface which are matched with the combination groove are designed near the combination groove; under any condition, the combination teeth can be smoothly inserted into the combination grooves with very small impact, so that the problems of clamping stagnation and difficulty in gear shifting are solved, the durability and the reliability of the gear shifting structure are greatly improved, and the frequency of maintenance and overhaul is greatly reduced. By designing the driving impact-resistant surface and the driven impact-resistant surface, edges and corners between the adjacent spiral surfaces are eliminated, so that the possibility of edge and corner collision is eliminated when the shifting fork sleeve is combined with a high-speed driven gear or a low-speed driven gear, and the gear shifting smoothness and the use durability are further improved.

Description

Technical Field

[0001] The utility model relates to the technical field of speed change systems, and in particular to an adaptive shifting structure, a speed changer and a rear axle assembly. Background Art

[0002] See also Figure 1 The existing low-cost rear axle assembly transmissions all shift gears by directly cooperating with the shift fork sleeve 2 and the high-speed driven gear 3 and the low-speed driven gear 4. Specifically, the two ends of the shift fork sleeve 2 are designed with coupling teeth 2a, and the high-speed driven gear 3 and the low-speed driven gear 4 are designed with coupling grooves 3a that match the coupling teeth 2a. During the high-speed rotation of the high-speed driven gear 3 or the low-speed driven gear 4, the shift fork sleeve 2 is inserted into the coupling groove 3a of the high-speed driven gear 3 or the low-speed driven gear 4 through the coupling teeth 2a at either end thereof, so that the shift fork sleeve 2 can rotate synchronously with one of the high-speed driven gear 3 and the low-speed driven gear 4.

[0003] Although the above-mentioned shifting structure has few parts and low cost, since the high-speed driven gear 3 and the low-speed driven gear 4 are always rotating at a high speed, there is a common problem of tooth knocking when the engaging tooth 2a is hard inserted into the engaging groove 3a. As a result, the existing low-cost rear axle assembly transmission not only has the problem of gear shifting jamming and difficulty, but also has extremely poor durability and reliability, and the frequency of maintenance and overhaul is extremely high.

[0004] Therefore, there is an urgent need to design a new gear shifting structure that can not only maintain the advantages of fewer parts and low cost, but also completely solve the problems of difficult gear shifting and poor durability. Utility Model Content

[0005] In order to solve the technical problems of difficult gear shifting and poor durability of the existing low-cost rear axle assembly transmission, the utility model provides an adaptive shifting structure, a transmission and a rear axle assembly.

[0006] The technical solution is as follows:

[0007] The invention relates to an adaptive shifting structure, comprising a shift shaft, a shift fork sleeve synchronously rotatably mounted on the shift shaft, and a high-speed driven gear and a low-speed driven gear both of which can be rotatably mounted on the shift shaft relative to the shift shaft. Both end surfaces of the shift fork sleeve are protruding with coupling teeth evenly distributed along the circumference thereof. Both end surfaces of the high-speed driven gear and the low-speed driven gear close to the shift fork sleeve have coupling grooves with the same number as the coupling teeth on the adjacent end surface of the shift fork sleeve. The shift fork sleeve can slide along the circumference of the shift shaft. When each coupling tooth on one end surface of the shift fork sleeve is inserted into the corresponding coupling groove, each coupling tooth on the other end surface of the shift fork sleeve is separated from the corresponding coupling groove, so that the shift fork sleeve rotates synchronously with one of the high-speed driven gear and the low-speed driven gear. The outer end surface of each coupling tooth has an active anti-shock surface with a conical or flat structure and an active anti-shock surface respectively located at the active anti-shock surface. The first helical surface of the combining tooth and the second helical surface of the combining tooth are on both sides of the surface, and the first helical surface of the combining tooth and the second helical surface of the combining tooth are helical surface structures with opposite rotation directions, and the protruding heights of the first helical surface of the combining tooth and the second helical surface of the combining tooth gradually decrease in the direction away from the corresponding active anti-impact surface, and there are passive anti-impact surfaces matched with the corresponding active anti-impact surfaces between the slots of adjacent combining grooves, and the first helical surface of the combining groove and the second helical surface of the combining groove are respectively located on both sides of the passive anti-impact surface, and the first helical surface of each combining groove is a helical surface structure matched with the corresponding first helical surface of the combining tooth, and gradually sinks and extends into the combining groove in the direction away from the corresponding passive anti-impact surface, and the second helical surface of each combining groove is a helical surface structure matched with the corresponding second helical surface of the combining tooth, and gradually sinks and extends into the combining groove in the direction away from the corresponding passive anti-impact surface.

[0008] A transmission comprises a gearbox, a power input shaft rotatably mounted on the gearbox, a transmission assembly and the above-mentioned adaptive shifting structure all mounted in the gearbox, wherein the shifting shaft is integrally formed with power output teeth, and the power input by the power input shaft is sequentially transmitted to the transmission assembly and the adaptive shifting structure, and then output outwardly by the power output teeth.

[0009] A rear axle assembly comprises a differential and the above-mentioned transmission, wherein the differential input gear of the differential is meshed with the power output gear.

[0010] Compared with the prior art, the utility model has the following beneficial effects:

[0011] The adaptive shifting structure, transmission and rear axle assembly adopting the above technical solution, by designing an active anti-impact surface, a first helical surface of the combining tooth and a second helical surface of the combining tooth, and designing a passive anti-impact surface, a first helical surface of the combining groove and a second helical surface of the combining groove near the combining groove, so that during the shifting process, the shift fork sleeve can: either directly insert the combining tooth into the combining groove; or first utilize the surface-to-surface anti-impact cooperation and spiral guiding cooperation of the first helical surface of the combining tooth and the first helical surface of the combining groove or the second helical surface of the combining tooth and the second helical surface of the combining groove, and then utilize the speed difference to make the combining tooth slide into the combining groove; or first utilize the surface-to-surface anti-impact cooperation of the active anti-impact surface and the passive anti-impact surface, and then utilize the speed difference to achieve the surface-to-surface anti-impact cooperation of the first helical surface of the combining tooth and the first helical surface of the combining groove or the second helical surface of the combining tooth The second helical surface of the tooth cooperates with the spiral guide of the second helical surface of the coupling groove, and finally the speed difference is used to make the coupling tooth slide into the coupling groove; therefore, under any circumstances, the coupling tooth can be smoothly inserted into the coupling groove with very small impact, which not only solves the problem of gear shifting jam and difficulty, but also greatly improves the durability and reliability of the gear shifting structure, and greatly reduces the extremely high frequency of maintenance and overhaul; among them, by designing the active anti-impact surface, the edges and corners between the first helical surface of the adjacent coupling tooth and the second helical surface of the coupling tooth are eliminated, and by designing the passive anti-impact surface, the edges and corners between the first helical surface of the coupling groove and the second helical surface of the coupling groove are eliminated, so that the possibility of angular collision when the fork sleeve is combined with the high-speed driven gear or the low-speed driven gear is reduced, further improving the smoothness of gear shifting and the durability of use. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 A schematic diagram of an existing low-cost rear axle assembly transmission;

[0013] Figure 2 It is a schematic diagram of the rear axle assembly of the utility model;

[0014] Figure 3 It is a schematic diagram of a shift fork sleeve, a high-speed driven gear and a low-speed driven gear of the utility model from one perspective;

[0015] Figure 4 It is a schematic diagram of the shift fork sleeve, the high-speed driven gear and the low-speed driven gear of the utility model from another perspective;

[0016] Figure 5 It is a structural schematic diagram of the shift fork sleeve of the utility model;

[0017] Figure 6 It is a structural schematic diagram of the high-speed driven gear of the utility model;

[0018] Figure 7 It is a structural schematic diagram of the low-speed driven gear of the utility model. DETAILED DESCRIPTION

[0019] The utility model is further described below in conjunction with embodiments and drawings.

[0020] Embodiment 1:

[0021] like Figure 2-Figure 7 As shown, an adaptive shifting structure mainly includes a shift shaft 1, a shift fork sleeve 2, a high-speed driven gear 3 and a low-speed driven gear 4, wherein the shift fork sleeve 2 is synchronously rotated on the shift shaft 1, and the high-speed driven gear 3 and the low-speed driven gear 4 can be rotatably mounted on the shift shaft 1 relative to the shift shaft 1.

[0022] The end surfaces of both ends of the shift fork sleeve 2 are protruded with coupling teeth 2a evenly distributed along the circumference thereof. The end surfaces of the high-speed driven gear 3 and the low-speed driven gear 4 close to the shift fork sleeve 2 are provided with coupling grooves 3a with the same number as the coupling teeth 2a on the adjacent end surface of the shift fork sleeve 2. The shift fork sleeve 2 can slide along the circumference of the shift shaft 1. When each coupling tooth 2a on the end surface of one end of the shift fork sleeve 2 is inserted into the corresponding coupling groove 3a, each coupling tooth 2a on the end surface of the other end of the shift fork sleeve 2 is separated from the corresponding coupling groove 3a, so that the shift fork sleeve 2 and one of the high-speed driven gear 3 and the low-speed driven gear 4 rotate synchronously. Since the outer diameter of the low-speed driven gear 4 is larger than the outer diameter of the high-speed driven gear 3, that is, when the shift fork sleeve 2 is combined with the high-speed driven gear 3, it is a high-speed gear, and the high-speed driven gear 3 drives the shift shaft 1 to rotate through the shift fork sleeve 2; when the shift fork sleeve 2 is combined with the low-speed driven gear 4, it is a low-speed gear, and the low-speed driven gear 4 drives the shift shaft 1 to rotate through the shift fork sleeve 2. Thereby, high and low speed shifting is realized, which not only has fewer parts and lowers the cost, but is also simple, reliable and easy to maintain.

[0023] See also Figure 3-Figure 7The outer end surface of each coupling tooth 2a has an active anti-impact surface 2a1 in a conical or flat structure and a first helical surface 2a2 and a second helical surface 2a3 of the coupling tooth located on both sides of the active anti-impact surface 2a1, respectively. The first helical surface 2a2 and the second helical surface 2a3 of the coupling tooth are helical surface structures with opposite rotation directions, and the protruding heights of the first helical surface 2a2 and the second helical surface 2a3 of the coupling tooth gradually decrease in the direction away from the corresponding active anti-impact surface 2a1. The notches of adjacent coupling grooves 3a are each provided with a The dynamic anti-impact surface 3a1 and the first helical surface 3a2 and the second helical surface 3a3 of the coupling groove are respectively located on both sides of the passive anti-impact surface 3a1. Each first helical surface 3a2 of the coupling groove is a helical surface structure adapted to the corresponding first helical surface 2a2 of the coupling tooth, and gradually sinks and extends into the coupling groove 3a in the direction away from the corresponding passive anti-impact surface 3a1. Each second helical surface 3a3 of the coupling groove is a helical surface structure adapted to the corresponding second helical surface 2a3 of the coupling tooth, and gradually sinks and extends into the coupling groove 3a in the direction away from the corresponding passive anti-impact surface 3a1.

[0024] Therefore, by designing the active anti-impact surface 2a1, the first helical surface 2a2 and the second helical surface 2a3 of the coupling tooth 2a, and designing the passive anti-impact surface 3a1, the first helical surface 3a2 and the second helical surface 3a3 of the coupling groove 3a to match them, the shift fork sleeve 2 only has the following three situations during the shifting process:

[0025] (1) The engaging tooth 2a is directly inserted into the engaging groove 3a; in this case, there is no impact at all during the process.

[0026] (2) First, the first helical surface 2a2 of the coupling tooth and the first helical surface 3a2 of the coupling groove or the second helical surface 2a3 of the coupling tooth and the second helical surface 3a3 of the coupling groove are used for anti-impact cooperation and spiral guiding cooperation, and then the speed difference is used to slide the coupling tooth 2a into the coupling groove 3a; in this case, the impact strength is reduced by the cooperation of the nut surface, because the impact strength generated by the cooperation of the surface to the surface is much smaller than the impact strength generated by the cooperation of the point to the surface, the line to the surface, the point to the line, the point to the point, and the line to the line.

[0027] (3) First, the active anti-impact surface 2a1 and the passive anti-impact surface 3a1 are face-to-face anti-impact matched, then the first helical surface 2a2 of the coupling tooth and the first helical surface 3a2 of the coupling groove or the second helical surface 2a3 of the coupling tooth and the second helical surface 3a3 of the coupling groove are face-to-face anti-impact matched and spiral guide matched, and finally the speed difference is used to make the coupling tooth 2a slide into the coupling groove 3a. In this process, the active anti-impact surface 2a1 is designed to eliminate the edges and corners between the adjacent first helical surfaces 2a2 and second helical surfaces 2a3 of the coupling tooth, and the passive anti-impact surface 3a1 is designed to eliminate the edges and corners between the first helical surface 3a2 of the coupling groove and the second helical surface 3a3 of the coupling groove, thereby reducing the possibility of edge collision when the fork sleeve 2 is coupled with the high-speed driven gear 3 or the low-speed driven gear 4, further improving the smoothness of shifting and the durability of use.

[0028] Therefore, in any of the above situations, the engaging tooth 2a can be smoothly inserted into the engaging groove with very little impact or even without impact, which not only solves the problem of gear shifting jam and difficulty, but also greatly improves the durability and reliability of the gear shifting structure, and greatly reduces the frequency of maintenance and overhaul.

[0029] See also Figure 2 A circle of fork mounting groove 2b is recessed on the outer circumferential surface of the fork sleeve 2 to facilitate the installation of the fork, which is simple and reliable.

[0030] Furthermore, the shift fork sleeve 2 and the shift shaft 1 are spline-matched, which not only ensures the reliability of synchronous rotation of the shift fork sleeve 2 and the shift shaft 1, but also facilitates processing.

[0031] For further information, see Figure 5-Figure 7 A coupling tooth guide slope 2a4 is provided between each coupling tooth first helical surface 2a2 and each coupling tooth second helical surface 2a3 and the corresponding side wall of the coupling tooth 2a in the rotation direction, and a coupling groove guide slope 3a4 is provided between each coupling groove first helical surface 3a2 and each coupling groove second helical surface 3a3 and the corresponding groove wall of the coupling groove 3a in the rotation direction. The cooperation between the coupling tooth guide slope 2a4 and the coupling groove guide slope 3a4 can make the coupling tooth 2a easier to slide into the coupling groove 3a, thereby improving the smoothness of the gear shifting and further reducing the gear shifting shock to a certain extent.

[0032] Furthermore, there is a first rounded corner 2a5 between the guide slope 2a4 of the coupling tooth and the corresponding side wall in the rotation direction of the coupling tooth 2a, a second rounded corner 2a6 between the guide slope 2a4 of the coupling tooth and the adjacent first helical surface 2a2 of the coupling tooth or the second helical surface 2a3 of the coupling tooth, a third rounded corner 3a5 between the guide slope 3a4 of the coupling groove and the corresponding groove wall in the rotation direction of the coupling groove 3a, and a fourth rounded corner 3a6 between the guide slope 3a4 of the coupling groove and the adjacent first helical surface 3a2 of the coupling groove or the second helical surface 3a3 of the coupling groove. Through the cooperation between the rounded corners, there is no collision between the edges and corners of the coupling tooth 2a when it is inserted into the coupling groove 3a, thereby further reducing the impact of gear shifting and improving the smoothness of gear shifting.

[0033] Furthermore, both side walls of the coupling tooth 2a in the rotation direction are inclined structures, so that the spacing between the side walls of the coupling tooth 2a in the rotation direction gradually decreases toward the direction close to its active anti-impact surface 2a1, and both groove walls of the coupling groove 3a in the rotation direction are inclined structures, so that the two groove walls of the coupling groove 3a in the rotation direction gradually increase toward the direction close to the groove opening. Through such a design, the coupling tooth 2a is easier to slide into the coupling groove 3a, improving the smoothness of gear shifting.

[0034] In this embodiment, both the active anti-impact surface 2a1 and the passive anti-impact surface 3a1 are preferably conical structures, which increases the contact area between the active anti-impact surface 2a1 and the passive anti-impact surface 3a1 relative to the planar structure, thereby further reducing the gear shifting shock.

[0035] Since the torque at low speed is greater than that at high speed, please refer to Figure 2 The tooth top height of each combining tooth 2a on the end surface of the fork sleeve 2 close to the high-speed driven gear 3 is smaller than the tooth top height of each combining tooth 2a on the end surface of the fork sleeve 2 close to the low-speed driven gear 4, and the radial width of each combining tooth 2a on the end surface of the fork sleeve 2 close to the high-speed driven gear 3 is smaller than the radial width of each combining tooth 2a on the end surface of the fork sleeve 2 close to the low-speed driven gear 4, which ensures the structural strength of each combining tooth 2a on the end surface of the fork sleeve 2 close to the low-speed driven gear 4 and improves durability.

[0036] Embodiment 2:

[0037] A transmission comprises a gearbox 5, a power input shaft 6 rotatably mounted on the gearbox 5, and a transmission assembly and an adaptive shift structure of embodiment 1 both mounted in the gearbox 5. A power output tooth 1a is integrally formed on the shift shaft 1. The power input by the power input shaft 6 is sequentially transmitted to the transmission assembly and the adaptive shift structure, and then output outwardly through the power output tooth 1a.

[0038] The power input from the power input shaft 6 is transmitted to the adaptive shifting structure through the transmission assembly, and then transmitted to the power output tooth 1a from the corresponding gear position by the adaptive shifting structure, and finally outputted to the outside.

[0039] The transmission assembly includes a primary driving tooth 6a integrally formed on the power input shaft 6, an intermediate shaft 7 parallel to the power input shaft 6 and the shift shaft 1, a secondary low-speed driving tooth 7a integrally formed on the intermediate shaft 7, and a secondary high-speed driving gear 8 and a primary driven gear 9 which are synchronously rotated and sleeved on the intermediate shaft 7. The primary driving tooth 6a meshes with the primary driven gear 9, the secondary high-speed driving gear 8 meshes with the high-speed driven gear 3, and the secondary low-speed driving tooth 7a meshes with the low-speed driven gear 4. Among them, the outer diameter of the secondary high-speed driving gear 8 is greater than the outer diameter of the secondary low-speed driving tooth 7a.

[0040] High speed gear: the shift fork sleeve 2 is combined with the high-speed driven gear 3, the power input shaft 6 drives the primary driven gear 9 to rotate through the primary driving tooth 6a, the primary driven gear 9 drives the intermediate shaft 7 to rotate synchronously, the intermediate shaft 7 drives the secondary high-speed driving gear 8 to rotate synchronously, the secondary high-speed driving gear 8 drives the high-speed driven gear 3 to rotate, the high-speed driven gear 3 drives the shift fork sleeve 2 to rotate synchronously, the shift fork sleeve 2 drives the shift shaft 1 to rotate, and the shift shaft 1 outputs power to the outside through the power output tooth 1a.

[0041] Low speed gear: the shift fork sleeve 2 is combined with the low-speed driven gear 4, the power input shaft 6 drives the primary driven gear 9 to rotate through the primary driving tooth 6a, the primary driven gear 9 drives the intermediate shaft 7 to rotate synchronously, the intermediate shaft 7 drives the low-speed driven gear 4 to rotate through the secondary low-speed driving tooth 7a, the low-speed driven gear 4 drives the shift fork sleeve 2 to rotate synchronously, the shift fork sleeve 2 drives the shift shaft 1 to rotate, and the shift shaft 1 outputs power to the outside through the power output tooth 1a.

[0042] The above two-stage reduction transmission method achieves a large reduction ratio, which can better reduce speed and increase torque.

[0043] Embodiment 3:

[0044] A rear axle assembly includes a differential 10 and a transmission of embodiment 2, wherein a differential input gear 10a of the differential 10 is meshed with a power output gear 1a.

[0045] In this embodiment, the differential 10 is installed at the bottom of the gearbox 5, with high integration and very compact structure.

[0046] Finally, it should be noted that the above description is only a preferred embodiment of the present invention. Under the guidance of the present invention, ordinary technicians in this field can make a variety of similar expressions without violating the purpose and claims of the present invention, and such changes fall within the scope of protection of the present invention.

Claims

1. An adaptive shifting structure, comprising a shifting shaft (1), a shifting fork sleeve (2) mounted on the shifting shaft (1) and capable of rotating synchronously, and a high-speed driven gear (3) and a low-speed driven gear (4) mounted on the shifting shaft (1) and capable of rotating relative to the shifting shaft (1), wherein both end surfaces of the shifting fork sleeve (2) are protrudingly formed with engaging teeth (2a) evenly distributed along the circumference thereof, and the end surfaces of the high-speed driven gear (3) and the low-speed driven gear (4) close to the shifting fork sleeve (2) are each provided with engaging teeth (2a) that are aligned with the shifting fork sleeve (2). The fork sleeve (2) has the same number of coupling grooves (3a) as the coupling teeth (2a) on adjacent end surfaces, the fork sleeve (2) can slide along the circumference of the shift shaft (1), when each coupling tooth (2a) on one end surface of the fork sleeve (2) is inserted into the corresponding coupling groove (3a), each coupling tooth (2a) on the other end surface of the fork sleeve (2) is separated from the corresponding coupling groove (3a), so that the fork sleeve (2) and one of the high-speed driven gear (3) and the low-speed driven gear (4) rotate synchronously, characterized in that: The outer end surface of each coupling tooth (2a) has an active anti-impact surface (2a1) in a conical or planar structure, and a first helical surface (2a2) and a second helical surface (2a3) of the coupling tooth respectively located on both sides of the active anti-impact surface (2a1), wherein the first helical surface (2a2) and the second helical surface (2a3) of the coupling tooth are helical surface structures with opposite rotation directions, and the protruding heights of the first helical surface (2a2) and the second helical surface (2a3) of the coupling tooth gradually decrease in a direction away from the corresponding active anti-impact surface (2a1), and the notches of adjacent coupling grooves (3a) have a groove adapted to the corresponding active anti-impact surface (2a1). A passive impact-resistant surface (3a1) and a first helical surface (3a2) and a second helical surface (3a3) of the coupling groove respectively located on both sides of the passive impact-resistant surface (3a1); each first helical surface (3a2) of the coupling groove is a helical surface structure matched with the first helical surface (2a2) of the corresponding coupling tooth, and gradually sinks and extends into the coupling groove (3a) in a direction away from the corresponding passive impact-resistant surface (3a1); each second helical surface (3a3) of the coupling groove is a helical surface structure matched with the second helical surface (2a3) of the corresponding coupling tooth, and gradually sinks and extends into the coupling groove (3a) in a direction away from the corresponding passive impact-resistant surface (3a1).

2. The adaptive shifting structure according to claim 1, characterized in that: A coupling tooth guide inclined surface (2a4) is provided between the first helical surface (2a2) of each coupling tooth and the second helical surface (2a3) of each coupling tooth and the corresponding side wall of the coupling tooth (2a) in the rotation direction, and a coupling groove guide inclined surface (3a4) is provided between the first helical surface (3a2) of each coupling groove and the second helical surface (3a3) of each coupling groove and the corresponding groove wall of the coupling groove (3a) in the rotation direction.

3. The adaptive shifting structure according to claim 2, characterized in that: A first rounded corner (2a5) is provided between the guide inclined surface (2a4) of the coupling tooth and the corresponding side wall of the coupling tooth (2a) in the rotation direction; a second rounded corner (2a6) is provided between the guide inclined surface (2a4) of the coupling tooth and the adjacent first helical surface (2a2) of the coupling tooth or the second helical surface (2a3) of the coupling tooth; a third rounded corner (3a5) is provided between the guide inclined surface (3a4) of the coupling groove and the corresponding groove wall in the rotation direction of the coupling groove (3a); and a fourth rounded corner (3a6) is provided between the guide inclined surface (3a4) of the coupling groove and the adjacent first helical surface (3a2) of the coupling groove or the second helical surface (3a3) of the coupling groove.

4. The adaptive shifting structure according to claim 1, characterized in that: Both side walls of the coupling tooth (2a) in the rotation direction are inclined structures, so that the spacing between the side walls of the coupling tooth (2a) in the rotation direction gradually decreases towards the direction close to its active anti-impact surface (2a1), and both groove walls of the coupling groove (3a) in the rotation direction are inclined structures, so that the spacing between the side walls of the coupling groove (3a) in the rotation direction gradually increases towards the direction close to the groove opening.

5. The adaptive shifting structure according to claim 1, characterized in that: The active anti-impact surface (2a1) and the passive anti-impact surface (3a1) are both conical surface structures.

6. The adaptive shifting structure according to claim 1, characterized in that: The tooth top height of each combined tooth (2a) on the end surface of the shift fork sleeve (2) close to the high-speed driven gear (3) is smaller than the tooth top height of each combined tooth (2a) on the end surface of the shift fork sleeve (2) close to the low-speed driven gear (4), and the radial width of each combined tooth (2a) on the end surface of the shift fork sleeve (2) close to the high-speed driven gear (3) is smaller than the radial width of each combined tooth (2a) on the end surface of the shift fork sleeve (2) close to the low-speed driven gear (4).

7. A transmission, characterized in that: The invention comprises a gearbox (5), a power input shaft (6) rotatably mounted on the gearbox (5), a transmission assembly mounted in the gearbox (5), and an adaptive shifting structure according to any one of claims 1 to 6, wherein a power output tooth (1a) is integrally formed on the shifting shaft (1), and the power inputted by the power input shaft (6) is successively transmitted to the transmission assembly and the adaptive shifting structure, and then outputted outwardly by the power output tooth (1a).

8. The transmission according to claim 7, characterized in that: The transmission assembly comprises a primary driving tooth (6a) integrally formed on a power input shaft (6), an intermediate shaft (7) parallel to the power input shaft (6) and the shift shaft (1), a secondary low-speed driving tooth (7a) integrally formed on the intermediate shaft (7), and a secondary high-speed driving gear (8) and a primary driven gear (9) both synchronously rotatably sleeved on the intermediate shaft (7), the primary driving tooth (6a) meshing with the primary driven gear (9), the secondary high-speed driving gear (8) meshing with the high-speed driven gear (3), and the secondary low-speed driving tooth (7a) meshing with the low-speed driven gear (4).

9. A rear axle assembly, characterized in that: The invention comprises a differential (10) and the transmission as claimed in claim 7, wherein the differential input gear (10a) of the differential (10) is meshed with the power output gear (1a).

10. The rear axle assembly according to claim 9, characterized in that: The differential (10) is installed at the bottom of the gearbox (5).

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