End tooth connecting structure and coaxial electric drive axle

Abstract

The utility model relates to the technical field of power transmission, in particular to an end tooth connecting structure and a coaxial electric drive axle. The end tooth connecting structure comprises a radial end tooth structure and an axial end tooth structure; a first spline groove is formed in an inner hole of the radial end tooth structure, outer end teeth are arranged on the outer circle of the radial end tooth structure, the first spline groove is connected with a spline of the first hollow shaft, and the axial outer end face of the outer end teeth is flush with the outer end face of the first hollow shaft. A second spline groove and an end tooth groove are sequentially formed in an inner hole of the axial end tooth structure, an open groove is formed in the outer circle and communicated with the end tooth groove, the second spline groove is in spline connection with the second hollow shaft, the end tooth groove is in clearance fit with the outer end tooth, and the axial inner end face of the outer end tooth is flush with the axial outer end face of the end tooth groove. According to the end tooth connection structure, the connection of the two parts can be realized without changing the sizes of the motor rotor shaft and the gear shaft, and the connection is easy to realize.

Description

Technical Field

[0001] The utility model relates to the technical field of power transmission, in particular to an end gear connection structure and a coaxial electric drive bridge. Background Art

[0002] With the rapid development of new energy technologies, the electric drive axle, as the core power transmission component of electric vehicles, has received increasing attention for its integration, high efficiency and compact design. The electric drive axle usually includes components such as motors, reducers, motor controllers, half shafts and wheel hubs, which work together to efficiently convert electrical energy into mechanical energy to drive the wheels. The gear shaft and the motor rotor shaft have the same aperture, and the shafts are both hollow thin-walled structures. The connection between the gear and the motor output shaft becomes complicated, that is, how to achieve the power coupling connection between the two hollow thin-walled shafts.

[0003] The prior art discloses a plum blossom elastic coupling, comprising a left half coupling, a right half coupling and a plum blossom elastic body. The left half coupling and the right half coupling are both provided with a center hole, the end faces of the left half coupling and the right half coupling are both provided with plum blossom-shaped convex teeth, a cylindrical hole is provided at the center of the plum blossom elastic body, a boss is provided on the left half coupling and the right half coupling and is located inside the convex teeth, and the two side surfaces of the convex teeth are concave arc-shaped, the plum blossom-shaped elastic body is installed between the left half coupling and the right half coupling, and the cylindrical boss of the plum blossom-shaped elastic body is placed in the gap between the convex teeth of the left half coupling and the right half coupling.

[0004] This solution is to solve the problem that the center of mass or inertia axis of the coupling does not coincide with its rotation axis due to various reasons, which will generate unbalanced centrifugal inertia force, centrifugal inertia couple and dynamic deflection (vibration mode) during operation. Therefore, a plum blossom elastic body is designed. However, under the requirements of high speed and high reliability of the electric drive system, the processing accuracy is high, and it is impossible to have the phenomenon of processing and assembly center deviation. Therefore, this design is redundant for the electric drive transmission system. The plum blossom elastic coupling cannot be applied to the electric drive transmission system with high requirements for power density, and the size and weight are large. Moreover, the coupling is a keyway connection. For the hollow thin-walled shaft structure, there is no shaft wall thickness support for machining the keyway. Utility Model Content

[0005] In view of the deficiencies in the prior art, the purpose of the embodiments of the utility model is to provide an end tooth connection structure, aiming to solve the problem of coaxial connection of electric drive axles in the prior art, especially the problem of power transmission of hollow thin-walled shafts.

[0006] In order to achieve the above purpose, the embodiment of the utility model provides the following technical solutions:

[0007] A end tooth connection structure, used for power transmission of two hollow shafts, comprises: a radial end tooth structure and an axial end tooth structure; the inner hole of the radial end tooth structure is provided with a first spline groove, and the outer circle is provided with an outer end tooth, the first spline groove is spline-connected to the first hollow shaft, and the axial outer end face of the outer end tooth is flush with the outer end face of the first hollow shaft; the inner hole of the axial end tooth structure is provided with a second spline groove and an end tooth groove in sequence, the outer circle is provided with an open groove, the open groove is connected with the end tooth groove, the second spline groove is spline-connected to the second hollow shaft, the end tooth groove is clearance-matched with the outer end tooth, and the axial inner end face of the outer end tooth is flush with the axial outer end face of the end tooth groove.

[0008] Optionally, the inner hole of the radial end tooth structure is a through hole, the outer circle of the first hollow shaft is provided with spline teeth matching with the first spline groove, the outer circle of the radial end tooth structure is a step shaft, the axial inner end of the step shaft is a small diameter shaft, and the axial outer end is a large diameter shaft, and the outer end teeth are arranged on the large diameter shaft.

[0009] Optionally, the inner hole of the axial end tooth structure is a stepped hole, the axial outer end of the stepped hole is a large diameter hole, and the axial inner end is a small diameter hole, the end tooth groove is arranged on the large diameter hole, the second spline groove is arranged on the small diameter hole, and the outer circle of the second hollow shaft is provided with spline teeth matching the second spline groove.

[0010] Optionally, the first spline groove of the radial end tooth structure is interference fit with the spline teeth of the first hollow shaft, and the second spline groove of the axial end tooth structure is interference fit with the spline teeth of the second hollow shaft.

[0011] Optionally, the outer circle of the axial end tooth structure is a stepped shaft, the axial outer end of the stepped shaft is a large diameter shaft, the axial inner end is a small diameter shaft, and a frustum is provided between the large diameter shaft and the small diameter shaft.

[0012] Optionally, the open groove is arranged on the large diameter shaft of the axial end tooth structure, and a plurality of open grooves are evenly distributed along the circumference of the large diameter shaft, each open groove is connected to the tooth groove of an end tooth groove, and the groove width of the open groove is 1-2 times the thickness of the tooth top of the end tooth groove.

[0013] Optionally, the outer end teeth of the radial end tooth structure are of involute tooth shape, and the end tooth grooves of the axial end tooth structure are of involute tooth profile.

[0014] Optionally, the axial length of the axial end tooth structure is twice the axial length of the radial end tooth structure.

[0015] Optionally, the end tooth connection structure further comprises a shaft retaining ring, the inner diameter of the shaft retaining ring is clamped on the second hollow shaft, and the outer diameter is clamped on the step hole of the axial end tooth structure.

[0016] An embodiment of the utility model also provides a coaxial electric drive bridge, including a gear shaft, a motor rotor shaft and the end tooth connection structure as described above, wherein the radial end tooth structure and the gear shaft are fitted by a spline interference fit, the axial end tooth structure and the radial end tooth structure are fitted by an end tooth clearance, the motor rotor shaft and the axial end tooth structure are fitted by a spline interference fit, and a shaft retaining ring is installed on the motor rotor shaft, and the shaft retaining ring is clamped on the step hole of the shaft end tooth structure.

[0017] One or more technical solutions provided in the embodiments of the present utility model have at least the following technical effects or advantages:

[0018] The two end tooth structures are connected to two thin-walled hollow shafts with power coupling requirements through splines, and the two end tooth structures are connected through the end teeth to transmit power. The outer end of the radial end tooth structure is aligned with the first hollow shaft, and the inner end of the end tooth is aligned with the outer end of the axial end tooth structure, so that the overall size can be very small, and the strength can also meet the power transmission requirements, realizing the power transmission requirements of the two hollow thin-walled shafts. When applied to a coaxial electric drive bridge, the connection of the two components can be achieved without changing the size of the motor rotor shaft and the gear shaft, and the connection is easy to achieve.

[0019] The two end teeth are spline-connected to the two hollow shafts respectively. The two end tooth structures can be easily engaged through the end tooth clearance to achieve the purpose of power transmission. If maintenance problems occur, the two hollow thin-walled shafts connected to the end tooth connection structure can also be easily separated, which can reduce maintenance costs when problems occur on each side.

[0020] The surface of the axial end tooth component is constructed as an open groove structure and is connected to the end tooth groove, which helps to dissipate heat and lubricate, reduce wear and extend the service life of the structure while reducing weight. Therefore, through the innovative end tooth connection structure, not only can the two hollow thin-walled shafts be reliably connected, but the compactness and lightness of the connection can also be improved, thereby improving the overall performance and power density of the electric drive axle and extending its service life.

[0021] Additional advantages of the present invention will be given in the following description, and some will become apparent from the following description or will be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention.

[0023] Figure 1 It is a schematic diagram of the end tooth connection structure provided by the embodiment of the utility model being installed on two hollow shafts;

[0024] Figure 2 It is an axonometric view of the radial end tooth structure provided by the embodiment of the utility model;

[0025] Figure 3 It is a cross-sectional view of the radial end tooth structure provided by an embodiment of the utility model;

[0026] Figure 4 It is a schematic diagram of the axial end tooth structure and the retaining ring provided in the embodiment of the utility model;

[0027] Figure 5 It is a cross-sectional view of the axial end tooth structure provided by an embodiment of the utility model;

[0028] Figure 6 It is an exploded view of the end tooth connection structure provided by an embodiment of the utility model;

[0029] Figure 7 This is an axonometric diagram of the end gear connection structure provided by the embodiment of the utility model;

[0030] Figure 8 It is a cross-sectional view of the assembly of the end tooth connection structure provided by the embodiment of the utility model;

[0031] Fig. 9 It is a schematic diagram of connecting a gear shaft and a motor rotor shaft with an end tooth connection structure provided by an embodiment of the utility model;

[0032] In the figure: 1, first hollow shaft; 2, radial end tooth structure; 21, first spline groove; 22, outer end tooth; 3, axial end tooth structure; 31, end tooth groove; 32, open groove; 33, second spline groove; 34, frustum; 4, second hollow shaft; 5, shaft retaining ring; 6, gear shaft; 7, motor rotor shaft;

[0033] In order to show the positions of various parts, the distances or sizes between them are exaggerated and the schematic diagram is for reference only. DETAILED DESCRIPTION

[0034] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0035] Electric drive axle: New energy electric drive axle generally integrates motor, reducer, motor controller, half shaft, wheel hub, etc.

[0036] Coaxial electric drive axle: the motor rotor shaft and the electric drive axle output half shaft are on the same axis.

[0037] Axle: The motor power is decelerated and torque increased by the reducer, and then transmitted to the wheel end through the axle.

[0038] Root circle: refers to the diameter of the circle passing through the root of the tooth groove, which is called the diameter of the root circle.

[0039] Under the requirements of integration, high speed ratio, and high volume power density of electric drive axles, the sun gear of the planetary gear reducer is often accompanied by a small number of teeth and a small module, resulting in a small diameter size. In order to meet the design requirements of the coaxial electric drive axle, the gear shaft of the sun gear needs to be made into a hollow shaft. The purpose of making the gear shaft into a hollow shaft is to allow the half shaft to pass through the middle of the gear shaft and transmit power to the wheels, so as to ensure that the input and output ends are on the same axis, that is, to meet the design of the coaxial electric drive axle. Similarly, the motor rotor shaft also needs to be processed into a hollow shaft, and the motor rotor shaft aperture must be consistent with the gear shaft aperture.

[0040] In order to ensure the machinability of the sun gear, the outer diameter of the gear shaft cannot exceed the root diameter of the sun gear. The small size of the sun gear leads to a very small diameter of the gear shaft. In order to ensure the torque requirement at the wheel end, the diameter of the half shaft is determined according to the design formula to meet the necessary safety strength coefficient. The aperture of the gear shaft must meet the smooth passage of the half shaft and ensure that there is a certain gap between the two, resulting in a limited thickness of the gear shaft entity. In this case, the gear shaft and the motor rotor shaft have similar diameters and the same aperture.

[0041] The volume and mass of the plum blossom elastic coupling are large, which is not conducive to the compact design and lightweight of the electric drive bridge. Due to the limitations of volume and mass, the existing plum blossom elastic coupling is difficult to achieve high power density, which affects the overall performance of the electric drive bridge. Moreover, when the plum blossom elastic coupling is connected to a hollow thin-walled shaft, the connection is difficult or unreliable due to the size limitation of the shaft. Therefore, when this coupling is applied to an electric drive bridge, especially a coaxial electric drive bridge, it is difficult to meet the requirements of high power density and compact design due to its large volume and heavy mass. If the right end of the sun gear is processed into a large-size shaft diameter (that is, the size is larger than the root circle diameter), the inner hole is processed with an internal spline, and connected with the external spline of the motor rotor shaft, this method greatly increases the difficulty of sun gear processing. If the two parts are directly welded together, the welding accuracy requirements are high, the shaft deformation is large, and disassembly and maintenance cannot be achieved. In order to solve the above technical problems, this embodiment proposes an end tooth connection structure for the power coupling connection of any two hollow thin-walled shafts with similar diameters.

[0042] like Figure 1 As shown, the end tooth connection structure includes a radial end tooth structure 2 and an axial end tooth structure 3; Figure 2 , Figure 3As shown, the inner hole of the radial end tooth structure 2 is provided with a first spline groove 21, and the outer circle is provided with an outer end tooth 22. The first spline groove 21 is spline-connected to the first hollow shaft 1, and the axial outer end surface of the outer end tooth 22 is flush with the outer end surface of the first hollow shaft 1 (as shown in FIG. Figure 1 As shown in Figure 4 , Figure 5 As shown, the inner hole of the axial end tooth structure 3 is provided with a second spline groove 33 and an end tooth groove 31 in sequence, and the outer circle is provided with an open groove 32, the open groove 32 is connected with the end tooth groove 31, the second spline groove 33 is spline-connected with the second hollow shaft 4, and the end tooth groove 31 is clearance-matched with the outer end tooth 22 (as shown in FIG. Figure 7 , Figure 8 As shown), the axial inner end surface of the outer end tooth 22 is flush with the axial outer end surface of the end tooth groove 31 (as shown Figure 1 As shown). The axial inner and outer ends of the radial end tooth structure 2 refer to the inner and outer ends of the radial end tooth structure 2 installed on the first hollow shaft 1. Figure 1 In the embodiment, the axial outer end of the radial end tooth structure 2 is the right end, and the axial inner end is the left end. Correspondingly, the axial inner and outer ends of the axial end tooth structure 3 refer to the inner and outer ends of the axial end tooth structure 3 installed on the second hollow shaft 4. Figure 1 In the figure, the axial outer end of the axial end tooth structure 3 is the left end, and the axial inner end is the right end.

[0043] The two end tooth structures are connected to two thin-walled hollow shafts with power coupling requirements through splines, and the two end tooth structures are connected through the end teeth to transmit power. The outer end of the end tooth of the radial end tooth structure 2 is aligned with the first hollow shaft 1, and the inner end of the end tooth is aligned with the outer end of the axial end tooth structure 3, so that the overall size can be very small, and the strength can also meet the power transmission requirements, and the power transmission requirements of the two hollow thin-walled shafts are realized. When applied to the coaxial electric drive bridge, the connection of the two components can be achieved without changing the size of the motor rotor shaft 7 and the gear shaft 6, and the connection is easy to achieve. Moreover, the two end teeth are connected to the two hollow shafts respectively by splines, and the two end tooth structures can be easily meshed through the end tooth clearance to achieve the purpose of power transmission. If there is a maintenance problem, the two hollow thin-walled shafts connected to the end tooth connection structure can also be easily separated, which can reduce the maintenance cost when problems occur in each. In addition, the surface of the axial end tooth component is constructed as an open groove 32 structure, which is connected to the end tooth groove 31, which helps to dissipate heat and lubricate while reducing weight, reducing wear and extending the service life of the structure. Therefore, through the innovative end tooth connection structure, not only can the two hollow thin-walled shafts be reliably connected, but the compactness and lightness of the connection can also be improved, thereby improving the overall performance and power density of the electric drive axle and extending its service life.

[0044] like Figure 2 , Figure 3As shown, the inner hole of the radial end tooth structure 2 is a through hole, the outer circle of the first hollow shaft 1 is provided with spline teeth that match the first spline groove 21, the outer circle of the radial end tooth structure 2 is a step shaft, the axial inner end of the step shaft is a small diameter shaft, the axial outer end is a large diameter shaft, and the outer end teeth 22 are provided on the large diameter shaft. This design not only improves the rigidity of the structure, but also facilitates installation and disassembly, maintenance and repair.

[0045] like Figure 4 , Figure 5 As shown, the inner hole of the axial end tooth structure 3 is a stepped hole, the axial outer end of the stepped hole is a large diameter hole, and the axial inner end is a small diameter hole, the end tooth groove 31 is arranged on the large diameter hole, the second spline groove 33 is arranged on the small diameter hole, and the outer circle of the second hollow shaft 4 is provided with spline teeth matching with the second spline groove 33. This design ensures a close fit with the axial end tooth structure 3 and effective transmission of power.

[0046] The first spline groove 21 of the radial end tooth structure 2 is interference fit with the spline teeth of the first hollow shaft 1, and the second spline groove 33 of the axial end tooth structure 3 is interference fit with the spline teeth of the second hollow shaft 4. This matching mode improves the reliability of the connection and ensures the stability of power transmission under high load conditions.

[0047] like Figure 5 As shown, the outer circle of the axial end tooth structure 3 is a stepped shaft, the axial outer end of the stepped shaft is a large diameter shaft, the axial inner end is a small diameter shaft, and a frustum 34 is provided between the large diameter shaft and the small diameter shaft. That is, the rear of the opening groove 32 of the axial end tooth structure 3 is constructed as a slope, which satisfies the arrangement of various structures under the premise of ensuring structural stability and load-bearing capacity.

[0048] The opening groove 32 is arranged on the large diameter shaft of the axial end tooth structure 3, and a plurality of opening grooves 32 are evenly distributed along the circumference of the large diameter shaft. Each opening groove 32 is connected to a tooth groove of an end tooth groove 31, and the groove width of the opening groove 32 is 1-2 times the thickness of the tooth top of the end tooth groove 31, which is 2 mm in this embodiment. The length of the opening groove 32 is consistent with the tooth width, which is 15 mm.

[0049] The outer end teeth 22 of the radial end tooth structure 2 are involute tooth shapes, and the end tooth grooves 31 of the axial end tooth structure 3 are involute tooth profiles. The outer end teeth 22 of the radial end tooth structure 2 are designed as involute tooth shapes, with a module of 2. In this embodiment, the number of teeth is designed to be 15, the tooth width is 15 mm, the pressure angle is 20°, and the helix angle is 0°. The end tooth grooves 31 of the axial end tooth structure 3 are involute tooth profiles, and the design parameters are consistent with the outer end teeth 22 to ensure that the two can be smoothly combined to maintain a stable transmission ratio and transmission efficiency under different working conditions.

[0050] Of course, it is understandable that the end tooth connection structure can select or design products of different sizes and numbers of teeth according to the changes in the place of use and purpose, and can realize the power transmission requirements of any two shafts of the same or different sizes. The connection is easy to combine and separate. The material can also be selected according to the different transmission loads. For those with large transmission load requirements, the material can be selected as chrome-molybdenum steel. After strict heat treatment, it has the characteristics of high hardness and wear resistance, which can increase the service life.

[0051] The axial length of the axial end tooth structure 3 is about twice the axial length of the radial end tooth structure 2, so that the overall size can be very small and the strength can also meet the power transmission requirements.

[0052] like Figure 1 , Figure 6 As shown, the end tooth connection structure also includes a shaft retaining ring 5, the inner diameter of which is clamped on the second hollow shaft 4, and the outer diameter is clamped on the stepped hole of the axial end tooth structure 3, for axial positioning and limiting axial movement. This design provides an additional fixing effect to prevent the end tooth structure from axially moving or disengaging under high load or impact.

[0053] Based on the above end gear connection structure, this embodiment also provides a coaxial electric drive bridge, such as Fig. 9 As shown, it includes a gear shaft 6, a motor rotor shaft 7 and an end tooth connection structure, the radial end tooth structure 2 and the gear shaft 6 are fitted through a spline interference fit, the axial end tooth structure 3 and the radial end tooth structure 2 are fitted through an end tooth clearance, the motor rotor shaft 7 and the axial end tooth structure 3 are fitted through a spline interference fit, and a shaft retaining ring 5 is installed on the motor rotor shaft 7, and the shaft retaining ring 5 is clamped on the step hole of the shaft end tooth structure.

[0054] The end gear connection structure plays the role of a connecting hub in the middle position, which can realize the transmission of power from the motor (right end) to the planetary carrier (left end). Since the end gears of the two parts are clearance-matched, the two can easily mesh to achieve the purpose of power transmission, and can be easily separated if maintenance problems occur. This ensures the stability and reliability of the power transmission system of the entire electric drive axle, and is convenient for installation and maintenance.

[0055] At the same time, the gear shaft 6 and the motor rotor shaft 7 are prevented from being connected by welding, which avoids the deformation of the sun gear caused by welding and the problems of difficult installation, disassembly and maintenance after welding. The end tooth connection mechanism can be standardized or used as a standard tooling supporting a bench dynamometer.

[0056] Although the above describes the specific implementation methods of the utility model in conjunction with the accompanying drawings, it is not intended to limit the protection scope of the utility model. Technical personnel in the relevant field should understand that on the basis of the technical solution of the utility model, various modifications or deformations that can be made by technical personnel in this field without creative work are still within the protection scope of the utility model.

Claims

1. An end tooth connection structure for power transmission between two hollow shafts, characterized in that: include: Radial end tooth structure and axial end tooth structure; The inner hole of the radial end tooth structure is provided with a first spline groove, and the outer circle is provided with an outer end tooth, the first spline groove is spline-connected with the first hollow shaft, and the axial outer end surface of the outer end tooth is flush with the outer end surface of the first hollow shaft; The inner hole of the axial end tooth structure is provided with a second spline groove and an end tooth groove in sequence, and the outer circle is provided with an open groove, the open groove is connected with the end tooth groove, the second spline groove is spline-connected with the second hollow shaft, the end tooth groove is clearance-matched with the outer end tooth, and the axial inner end face of the outer end tooth is flush with the axial outer end face of the end tooth groove.

2. The end tooth connection structure according to claim 1, characterized in that: The inner hole of the radial end tooth structure is a through hole, the outer circle of the first hollow shaft is provided with spline teeth matching with the first spline groove, the outer circle of the radial end tooth structure is a stepped shaft, the axial inner end of the stepped shaft is a small diameter shaft, the axial outer end is a large diameter shaft, and the outer end teeth are arranged on the large diameter shaft.

3. The end tooth connection structure according to claim 2, characterized in that: The inner hole of the axial end tooth structure is a stepped hole, the axial outer end of the stepped hole is a large diameter hole, and the axial inner end is a small diameter hole. The end tooth groove is arranged on the large diameter hole, and the second spline groove is arranged on the small diameter hole. The outer circle of the second hollow shaft is provided with spline teeth matching with the second spline groove.

4. The end tooth connection structure according to claim 3, characterized in that: The first spline groove of the radial end tooth structure is interference fit with the spline teeth of the first hollow shaft, and the second spline groove of the axial end tooth structure is interference fit with the spline teeth of the second hollow shaft.

5. The end tooth connection structure according to claim 1, characterized in that: The outer circle of the axial end tooth structure is a stepped shaft, the axial outer end of the stepped shaft is a large diameter shaft, the axial inner end is a small diameter shaft, and a frustum is provided between the large diameter shaft and the small diameter shaft.

6. The end tooth connection structure according to claim 5, characterized in that: The open groove is arranged on the large diameter shaft of the axial end tooth structure, and a plurality of open grooves are evenly distributed along the circumference of the large diameter shaft, each open groove is connected to the tooth groove of an end tooth groove, and the groove width of the open groove is 1-2 times the thickness of the tooth top of the end tooth groove.

7. The end tooth connection structure according to claim 1, characterized in that: The outer end teeth of the radial end tooth structure are involute tooth shapes, and the end tooth grooves of the axial end tooth structure are involute tooth profiles.

8. The end tooth connection structure according to claim 1, characterized in that: The axial length of the axial end tooth structure is twice the axial length of the radial end tooth structure.

9. The end tooth connection structure according to claim 3, characterized in that: The end tooth connection structure also includes a shaft retaining ring, the inner diameter of which is clamped on the second hollow shaft, and the outer diameter of which is clamped on the step hole of the axial end tooth structure.

10. A coaxial electric drive bridge, characterized in that: It includes a gear shaft, a motor rotor shaft and an end tooth connection structure as described in any one of claims 1 to 9, the radial end tooth structure and the gear shaft are fitted by spline interference, the axial end tooth structure and the radial end tooth structure are fitted by end tooth clearance, the motor rotor shaft and the axial end tooth structure are fitted by spline interference, and a shaft retaining ring is installed on the motor rotor shaft, and the shaft retaining ring is clamped on the step hole of the shaft end tooth structure.

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