Powertrain for preventing bearing electrical corrosion, and electric vehicle

Abstract

Provided in the present application are a powertrain for preventing bearing electrical corrosion, and an electric vehicle. A housing of the powertrain is used for accommodating a drive electric motor, and the drive electric motor comprises an electric motor shaft and an electric motor stator. The electric motor shaft is used for driving wheels through a speed reducer. The housing comprises an axial housing arranged on one side of the electric motor stator in the axial direction of the electric motor shaft, and the end face of the axial housing facing the electric motor stator comprises a bearing groove and an axial protrusion. The bearing groove is used for accommodating an electric motor bearing so as to be in transmission connection with the electric motor shaft. One end of the axial protrusion is configured for fixedly connecting to the bottom of the bearing groove, and the other end of the axial protrusion is configured for extending into a shaft hole of the electric motor shaft in the axial direction of the electric motor shaft. The end face of the other end of the axial protrusion comprises a through hole for communicating an internal flow channel of the axial housing with the shaft hole of the electric motor shaft. A gap between the axial protrusion and the shaft hole is used for accommodating an electrically conductive structure. The powertrain provided in the present application conducts, by means of a structure of the housing that supplies oil to the shaft hole of the electric motor shaft, a shaft current of the electric motor shaft to the housing for grounding so as to protect the electric motor bearing.

Description

Powertrain and electric vehicles protected against bearing electrolytic corrosion

[0001] This application claims priority to Chinese Patent Application No. 202411465275.2, filed on October 18, 2024, with the invention entitled "Powertrain and Electric Vehicle for Preventing Electrical Corrosion of Bearings", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of electric vehicle technology, specifically to a powertrain that prevents bearing electro-corrosion and an electric vehicle. Background Technology

[0003] In the powertrain of electric vehicles, during operation, the shaft voltage of the drive motor can break down the oil film in the motor bearing, causing bearing electro-corrosion. This leads to localized melting and unevenness at the bearing contact surfaces. Bearing electro-corrosion not only degrades bearing performance and causes premature bearing failure on the motor shaft, but also reduces the overall lifespan of the powertrain. Summary of the Invention

[0004] This application provides a powertrain for preventing bearing electro-corrosion and an electric vehicle. By utilizing a structure in which the powertrain housing supplies oil to the shaft hole of the motor shaft, the shaft current of the motor shaft is conducted to the housing ground to protect the motor bearing.

[0005] In a first aspect, this application provides a powertrain that prevents bearing electro-corrosion. The powertrain housing houses a drive motor. The drive motor includes a motor shaft and a motor stator, the motor shaft driving wheels via a reducer. The housing includes an axial housing arranged axially along the motor shaft on one side of the motor stator. The end face of the axial housing facing the motor stator includes a bearing groove and an axial protrusion. The bearing groove accommodates a motor bearing, which is used for transmission connection to the motor shaft. One end of the axial protrusion is used to fix the bottom of the bearing groove, and the other end of the axial protrusion extends axially into a shaft hole of the motor shaft. The end face of the other end of the axial protrusion includes a through hole, which connects the internal flow channel of the axial housing and the shaft hole of the motor shaft. The gap between the outer peripheral surface of the axial protrusion and the inner peripheral surface of the shaft hole accommodates a conductive structure for conducting electrical connections between the outer peripheral surface of the axial protrusion and the inner peripheral surface of the shaft hole.

[0006] The powertrain provided in this application for preventing bearing electro-corrosion forms a bearing groove in the axial portion of the housing. The groove wall is used to fix the motor bearing and drives the motor shaft of the motor through the motor bearing. The bottom of the bearing groove is used to fix an axial protrusion, which extends into the shaft hole of the motor shaft and delivers lubricating oil or coolant towards the shaft hole. The powertrain provided in this application also conducts an electrical connection between the outer peripheral surface of the axial protrusion and the inner peripheral surface of the shaft hole through a conductive structure, so as to conduct the shaft end current of the motor shaft to the housing for grounding, preventing the shaft end current from flowing through the motor bearing and causing motor bearing failure. The powertrain provided in this application makes reasonable use of the internal space of the motor shaft hole to achieve the electrical connection between the motor shaft and the housing, effectively protecting the motor bearing and extending the service life of the powertrain.

[0007] In one implementation, the axial bore along the motor shaft comprises two sections, one section for accommodating a conductive structure, and the other end of the axial protrusion for extending through the conductive structure into another section of the motor shaft. The gap between the outer circumferential surface of the axial protrusion and the inner circumferential surface of one section is greater than the gap between the outer circumferential surface of the axial protrusion and the inner circumferential surface of the other section along the radial direction of the motor shaft.

[0008] In this implementation, the motor shaft bore is divided into two sections with different inner diameters. Along the axial direction of the motor shaft, the outer circumferential surface of the axially protruding section and the inner circumferential surface of one section form two gaps with different radial dimensions. The radial dimension of one gap is larger than that of the other gap. One gap is used to accommodate the conductive structure, while the axially protruding section in the other gap delivers lubricating oil or coolant towards the shaft bore. This ensures that the coolant or lubricating oil reliably enters the motor shaft bore while providing sufficient installation space for the conductive structure.

[0009] In one implementation, the axial conductive structure along the motor shaft includes two opposite end faces, one of which is positioned between the other end face and the bottom of the bearing groove, and the distance between the axially protruding end and one end face is smaller than the distance between the other end of the axially protruding end and the other end face.

[0010] In this implementation, the conductive structure is closer to the bottom of the bearing groove along the axial direction of the motor shaft and farther from the axial protrusion of the oil nozzle that delivers lubricating oil or coolant. This reduces the contact between the conductive structure and the coolant or lubricating oil, preventing the conductive structure from failing prematurely due to excessive immersion in the coolant or lubricating oil.

[0011] In one implementation, along the axial direction of the motor shaft, the outer peripheral surface of the axially protruding section includes a mating segment, and a conductive structure is used to conduct electrical connection between the outer peripheral surface of the mating segment and the inner peripheral surface of the shaft hole. The outer diameter of the mating segment is smaller than the outer diameter of the remaining portion of the axially protruding section along the radial direction of the motor shaft.

[0012] In this implementation, the mating section forms a limiting groove on the outer peripheral surface of the axial protrusion. The limiting groove restricts the displacement of the conductive structure relative to the axial protrusion along the motor shaft, ensuring reliable contact between the conductive structure and the outer peripheral surface of the axial protrusion and achieving electrical connection.

[0013] In one implementation, the length of the mating section along the axial direction of the motor shaft is greater than or equal to the length of the conductive structure.

[0014] In this implementation, the inner circumferential surface of the conductive structure can be completely fitted with the mating section. The limiting groove completely accommodates the conductive structure to restrict its axial displacement along the motor shaft.

[0015] In one implementation, the two shaft holes of the motor shaft are used to form a stepped surface, with the stepped surface facing the conductive structure along the axial direction of the motor shaft, and the distance between the stepped surface and the conductive structure is smaller than the distance between the bottom of the bearing groove and the conductive structure.

[0016] In this implementation, the smaller the distance between the axial stepped surface along the motor shaft and the conductive structure, the longer the length of the axial protrusion extending into the other section of the shaft hole. Because the radial dimension of the gap between the other section of the shaft hole and the axial protrusion is small, the coolant or lubricating oil has to travel a longer distance to flow back from the other section of the shaft hole to the first section, which can reduce the contact between the conductive structure and the coolant or lubricating oil.

[0017] In one implementation, the inner circumferential surface of a segment of the axial bore along the motor shaft includes another mating segment, and a conductive structure is used to conduct electrical connection between the inner circumferential surface of the other mating segment and the outer circumferential surface of the axially protruding section. The inner diameter of the other mating segment is larger than the inner diameter of the remaining portion of the segment of the bore along the radial direction of the motor shaft.

[0018] In this implementation, another mating section is used to form a positioning groove on the inner circumferential surface of the shaft hole. The positioning groove is used to limit the displacement of the conductive structure relative to the shaft hole along the axial direction of the motor shaft, so as to ensure reliable contact between the conductive structure and the inner circumferential surface of the shaft hole and to achieve electrical connection.

[0019] In one implementation, along the axial direction of the motor shaft, the length of another mating segment is greater than or equal to the length of the conductive structure.

[0020] In this implementation, the outer peripheral surface of the conductive structure can be fully fitted with another mating segment. Furthermore, the positioning groove fully accommodates the conductive structure to limit its axial displacement along the motor shaft.

[0021] In one implementation, the outer circumferential surface of the motor shaft along the axial direction includes a first segment and a second segment connected together. Radially along the motor shaft, the outer diameter of the first segment is smaller than the outer diameter of the second segment and greater than or equal to the inner diameter of the motor bearing.

[0022] In this implementation, a first segment of the outer circumferential surface of the motor shaft is used to embed into the inner hole of the motor bearing. The outer circumferential surface of the motor shaft forms a stepped surface through the first and second segments. This stepped surface faces the bottom of the bearing groove along the axial direction of the motor shaft. The stepped surface abuts against the side of the motor bearing to limit the axial displacement of the motor bearing relative to the motor shaft.

[0023] In one implementation, along the axial direction of the motor shaft, the length of the first segment is greater than the length of one segment of the shaft hole.

[0024] In this implementation, the additional stepped surface along the axial direction of the motor shaft coincides with another section of the shaft hole. That is, the additional stepped surface is located on another section of the shaft hole along the axial direction of the motor shaft. This additional stepped surface provides greater structural stability within the motor shaft and better restricts the axial displacement of the motor bearing relative to the motor shaft.

[0025] In one implementation, the conductive structure is annular. Along the radial direction of the motor shaft, the outer diameter of the conductive structure is greater than or equal to the inner diameter of the shaft hole of the motor shaft, and the inner diameter of the conductive structure is less than or equal to the outer diameter of the axial protrusion.

[0026] In this implementation, the outer peripheral surface of the conductive structure forms an interference fit with the inner peripheral surface of the motor shaft hole, or the outer peripheral surface of the conductive structure fits against the inner peripheral surface of the motor shaft hole through elastic deformation, to ensure reliable contact between the conductive structure and the shaft hole to form an electrical connection. The inner peripheral surface of the conductive structure forms an interference fit with the outer peripheral surface of the axially protruding part, or the inner peripheral surface of the conductive structure fits against the outer peripheral surface of the axially protruding part through elastic deformation, to ensure reliable contact between the conductive structure and the axially protruding part to form an electrical connection.

[0027] In one implementation, the conductive structure includes an axial sleeve. The conductive structure is fixed to the outer peripheral surface of an axially protruding portion via the axial sleeve, and the outer peripheral surface of the conductive structure is used to coat a wear-resistant conductive coating.

[0028] In this implementation, an axial sleeve extends axially along the motor shaft to increase the contact area between the conductive structure and the axial protrusion, thereby fixing the conductive structure to the outer peripheral surface of the axial protrusion. During motor operation, the motor shaft rotates within the housing, and the inner peripheral surface of the motor shaft's bore continuously rubs against the outer peripheral surface of the conductive structure. The wear-resistant conductive coating applied to the outer peripheral surface of the conductive structure reduces wear on the outer peripheral surface and establishes an electrical connection between the outer peripheral surface of the conductive structure and the inner peripheral surface of the motor shaft's bore.

[0029] In one implementation, the conductive structure is fixed to the inner circumferential surface of the shaft hole by an axial sleeve, and the inner circumferential surface of the conductive structure is used to coat a wear-resistant conductive coating.

[0030] In this implementation, an axial sleeve extends axially along the motor shaft to increase the contact area between the conductive structure and the shaft hole of the motor shaft, thereby fixing the conductive structure to the inner circumferential surface of the shaft hole. During motor operation, the conductive structure rotates within the housing along with the motor shaft, and the inner circumferential surface of the conductive structure continuously rotates and rubs against the axially protruding outer circumferential surface. The wear-resistant conductive coating applied to the inner circumferential surface of the conductive structure reduces wear on the inner circumferential surface and establishes an electrical connection between the inner circumferential surface of the conductive structure and the axially protruding outer circumferential surface.

[0031] In one implementation, the axial sleeve extends along the axial direction of the motor shaft toward the bottom of the bearing groove.

[0032] In this implementation, along the axial direction of the motor shaft, the axial sleeve is positioned opposite the shaft hole near the motor shaft. The conductive structure electrically connects the inner circumferential surface of the shaft hole and the axially protruding outer circumferential surface on the side near the bottom of the bearing groove. The conductive structure is positioned away from the shaft hole relative to the portion used for conduction and electrical connection, reducing contact between the conductive structure and coolant or lubricating oil to extend its service life.

[0033] In one implementation, the conductive structure includes a radial protrusion. The conductive structure provides electrical connection between the outer peripheral surface of the axial protrusion and the inner peripheral surface of the shaft hole via the radial protrusion. The radial protrusion is used to fix the axial sleeve to one end near the bottom of the bearing groove along the axial direction of the motor shaft.

[0034] In one implementation, the conductive structure includes an inner ring and an outer ring. The inner and outer rings are sequentially fitted onto the axially protruding outer peripheral surface along the motor shaft, with the outer diameter of the inner ring being larger than the inner diameter of the outer ring.

[0035] In this implementation, the conductive structure consists of nested inner and outer rings. The outer circumferential surface of the inner ring and the inner circumferential surface of the outer ring form an interference fit or abut against each other through elastic deformation to ensure a reliable electrical connection between the inner and outer rings.

[0036] In this implementation, one of the inner and outer rings is a conductive bearing, and the other is a conductive rubber ring.

[0037] In this implementation, the conductive bearing and the conductive rubber ring have different stiffnesses. The conductive bearing has higher stiffness, and the inner or outer ring formed by the conductive bearing can improve the overall structural stability of the conductive structure. The conductive rubber ring has lower stiffness, and the outer or inner ring formed by the conductive rubber ring is used to offset the wear of the conductive structure through elastic deformation, thereby ensuring the reliability of the electrical connection. By differentiating the structure or materials of the inner and outer rings, the conductive structure can achieve both structural reliability and wear resistance.

[0038] In one implementation, the length of the axial conductive rubber ring along the motor shaft is less than the length of the conductive bearing. The inner ring is a conductive bearing, and the gap between the portion of the conductive bearing's outer circumference extending beyond the conductive rubber ring and one end of the shaft hole is less than the gap between the other end of the shaft hole and the other end of the axial protrusion.

[0039] In one implementation, the outer ring is a conductive bearing, and the gap between the portion of the inner circumferential surface of the conductive bearing that extends beyond the conductive rubber ring and the axial protrusion is smaller than the gap between the other part of the shaft hole and the other end of the axial protrusion.

[0040] In the two implementation methods mentioned above, because the conductive bearing has high rigidity, the part of the conductive bearing that extends beyond the conductive rubber ring due to the radial movement of the motor shaft can be used to abut against the outer peripheral surface of the axial protrusion or the inner peripheral surface of the shaft hole, thus preventing the axial protrusion from contacting the other part of the shaft hole and preventing the axial protrusion from affecting the delivery of coolant or lubricating oil toward the shaft hole due to collision deformation.

[0041] In one implementation, two conductive rubber rings are used. These two conductive rubber rings are spaced apart along the axial direction of the motor shaft, and the sum of the distance between the two conductive rubber rings and their lengths is less than or equal to the length of the conductive bearing.

[0042] In this implementation, two conductive rubber rings spaced apart along the axial direction of the motor shaft can distribute the impact force of the radial movement of the motor shaft more evenly onto the conductive bearing, thereby improving the internal stress conditions of the conductive structure and extending its service life.

[0043] In one implementation, the inner ring is a conductive bearing, and the gap between the inner circumferential surface of the shaft hole located between the two conductive rubber rings along the axial direction of the motor shaft and the outer circumferential surface of the conductive bearing is smaller than the gap between the other end of the shaft hole and the other end of the axial protrusion.

[0044] In one implementation, the outer ring is a conductive bearing, and the gap between the outer peripheral surface of the axial protrusion located between the two conductive rubber rings along the axial direction of the motor shaft and the inner peripheral surface of the conductive bearing is smaller than the gap between the other end of the shaft hole and the other end of the axial protrusion.

[0045] In the two implementation methods mentioned above, because the conductive bearing has high rigidity, the radial movement of the motor shaft causes the part of the conductive bearing located between the two conductive rubber rings to abut against the outer peripheral surface of the axial protrusion or the inner peripheral surface of the shaft hole, thus preventing the axial protrusion from contacting the other part of the shaft hole and preventing the axial protrusion from affecting the delivery of coolant or lubricating oil toward the shaft hole due to collision deformation.

[0046] In one implementation, the elastic modulus of the conductive rubber ring is greater than that of the other conductive rubber ring.

[0047] In this implementation, by differentiating the elastic moduli of the materials of the two conductive rubber rings, the radial elastic forces of the two conductive rubber rings along the motor shaft can be differentiated. After long-term operation of the powertrain provided in this application, the wear amounts of the two conductive rubber rings will differ, and the conductive rubber ring with smaller wear can compensate for the wear amount of the other conductive rubber ring through elastic deformation.

[0048] In one implementation, axially conductive rubber rings are arranged between another conductive rubber ring and the bottom of the bearing groove.

[0049] In this implementation, the conductive rubber ring with a smaller axial elastic modulus along the motor shaft is closer to the other end of the shaft hole. Radial movement of the motor shaft causes greater compression of the conductive rubber ring, thus creating a sealing effect and reducing contact between the conductive rubber ring and the coolant or lubricating oil, thereby protecting the conductive rubber ring.

[0050] Secondly, this application provides an electric vehicle, which includes wheels and a powertrain provided by any implementation of the first aspect described above, the powertrain being used to drive the wheels of the electric vehicle. The electric vehicle provided in the embodiments of this application employs the aforementioned powertrain, resulting in a more compact structure and a longer service life. Attached Figure Description

[0051] Figure 1 is a schematic diagram of the external appearance of an electric vehicle provided in an embodiment of this application;

[0052] Figure 2 is a schematic diagram of a transmission system for an electric vehicle provided in an embodiment of this application;

[0053] Figure 3 is a cross-sectional schematic diagram of a drive motor provided in an embodiment of this application;

[0054] Figure 4 is a cross-sectional schematic diagram of a powertrain provided in an embodiment of this application;

[0055] Figure 5 is a partially enlarged schematic diagram of a powertrain provided in an embodiment of this application;

[0056] Figure 6 is another partially enlarged schematic diagram of the powertrain provided in the embodiment of this application;

[0057] Figure 7 is another exploded view of the powertrain provided in the embodiment of this application;

[0058] Figure 8 is another cross-sectional schematic diagram of the powertrain provided in the embodiment of this application;

[0059] Figure 9 is another exploded view of the powertrain provided in the embodiment of this application;

[0060] Figure 10 is another cross-sectional schematic diagram of the powertrain provided in the embodiment of this application;

[0061] Figure 11 is another exploded view of the powertrain provided in the embodiment of this application;

[0062] Figure 12 is another cross-sectional schematic diagram of the powertrain provided in the embodiment of this application;

[0063] Figure 13 is another cross-sectional schematic diagram of the powertrain provided in the embodiment of this application;

[0064] Figure 14 is another cross-sectional schematic diagram of the powertrain provided in the embodiment of this application;

[0065] Figure 15 is another cross-sectional schematic diagram of the powertrain provided in the embodiment of this application;

[0066] Figure 16 is another cross-sectional schematic diagram of the powertrain provided in the embodiment of this application;

[0067] Figure 17 is another cross-sectional schematic diagram of the powertrain provided in the embodiment of this application;

[0068] Figure 18 is another schematic diagram of the powertrain provided in the embodiment of this application;

[0069] Figure 19 is another cross-sectional schematic diagram of the powertrain provided in the embodiment of this application. Detailed Implementation

[0070] The technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0071] This application provides a powertrain designed to prevent bearing electro-corrosion. The powertrain housing houses a drive motor. The drive motor includes a motor shaft and a motor stator, with the motor shaft driving wheels via a reducer. The housing includes an axial housing arranged axially along the motor shaft on one side of the motor stator. The end face of the axial housing facing the motor stator includes a bearing groove and an axial protrusion. The bearing groove accommodates a motor bearing, which is used for transmission connection to the motor shaft. One end of the axial protrusion is used to fix the bottom of the bearing groove, and the other end extends axially into a shaft hole of the motor shaft. The end face of the other end of the axial protrusion includes a through hole, which connects the internal flow channel of the axial housing to the shaft hole of the motor shaft. The gap between the outer circumferential surface of the axial protrusion and the inner circumferential surface of the shaft hole accommodates a conductive structure, which conducts electrical connection between the outer circumferential surface of the axial protrusion and the inner circumferential surface of the shaft hole. The powertrain provided in this application efficiently utilizes the internal space of the motor shaft's shaft hole to achieve electrical connection between the motor shaft and the housing. It effectively protects the motor bearings and extends the service life of the powertrain.

[0072] This application provides an electric vehicle, which includes wheels and a powertrain provided in the embodiments of this application. The powertrain is used to drive the wheels of the electric vehicle. The electric vehicle provided in the embodiments of this application uses the powertrain provided in the embodiments of this application, resulting in a more compact structure and a longer service life.

[0073] Figure 1 is a schematic diagram of the external appearance of an electric vehicle 200 provided in an embodiment of this application. As shown in Figure 1, the electric vehicle 200 includes a battery 101, wheels 102, and a powertrain 100. The battery 101 supplies power to the powertrain 100. The powertrain 100 drives the wheels 102 to rotate, providing power to the electric vehicle 200.

[0074] Please refer to Figure 2, which shows a transmission diagram of an electric vehicle 200 provided in an embodiment of this application, and Figure 3, which shows a cross-sectional view of a drive motor 20 provided in an embodiment of this application.

[0075] The powertrain 100 for preventing bearing electro-corrosion provided in this application includes a housing 10 and a drive motor 20. The drive motor 20 includes a motor shaft 211, a motor rotor 21 and a motor stator 22, wherein the housing 10 is used to house the drive motor 20.

[0076] In one embodiment, as shown in FIG3, the stator 22 of the drive motor 20 is fixedly connected to the housing 10 of the powertrain 100. The stator 22 is coaxially sleeved on the periphery of the motor rotor 21. The motor shaft 211 passes through the motor rotor 21 and is connected to the motor rotor 21 for transmission. The stator 22 is also used for electrical connection with the drive circuit. After the motor stator 22 is energized, it will generate an alternating magnetic field based on the alternating current of the drive circuit to drive the motor rotor 21 to rotate and drive the motor shaft 211 to rotate coaxially, so that the drive motor 20 transmits driving force to the wheel 102 through the motor shaft 211.

[0077] In one embodiment, the powertrain 100 includes a reducer 103. The motor shaft 211 of the powertrain 100 drives the wheel 102 through the reducer 103, and the axis of the wheel 102 is parallel to the axis of the motor shaft 211 of the powertrain 100. In another embodiment, the powertrain 100 is fixed to the frame of the electric vehicle 200 by a housing 10. The reducer 103 is connected between the motor shaft 211 of the drive motor 20 and the axle of the wheel 102. The driving force output by the drive motor 20 through the motor shaft 211 is transmitted to the wheel 102 through the reducer 103 to drive the wheel 102 to rotate, thereby driving the electric vehicle 200 to move.

[0078] In one embodiment, the reducer 103 includes a gear set comprising multiple pairs of meshing gears. The gear set is located within a receiving cavity formed by the housing 10, and along the axial direction of the motor shaft 211, the gear set is located on one side of the motor stator 22. The end of the motor shaft 211 facing the reducer 103 meshes with a transmission gear of the gear set to drive the reducer 103 to drive the wheel 102.

[0079] The powertrain 100 also includes two motor bearings 30. The two motor bearings 30 are arranged on both sides of the motor stator 22 along the axial direction of the motor shaft 211. The inner rings of the two motor bearings 30 are respectively connected to the two ends of the motor shaft 211 for transmission, and the outer rings of the two motor bearings 30 are fixedly connected to the housing 10, so that the motor shaft 211 is rotatably connected to the housing 10 through the motor bearings 30. That is, the housing 10 supports the motor shaft 211 through the two motor bearings 30.

[0080] In one embodiment, one end of the motor shaft 211 is used to fixally connect to one end of a drive shaft of the reducer 103, and the other end of the drive shaft of the reducer 103 is used to embed into the inner ring of a motor bearing 30 and is fixed to the housing 10 by the outer ring of the motor bearing 30. This also allows the motor shaft 211 to be rotatably connected to the housing 10 via the motor bearing 30, meaning the housing 10 supports the motor shaft 211 and one drive shaft of the reducer 103 via two motor bearings 30.

[0081] In one embodiment, the housing 10 includes an axial housing, a circumferential housing, and another axial housing arranged sequentially along the axial direction of the motor shaft 211. The circumferential housing includes an inner cavity that extends through the circumferential housing along the axial direction of the motor shaft 211. The two axial housings are respectively fixed to both sides of the circumferential housing along the axial direction of the motor shaft 211 to enclose the inner cavity of the circumferential housing to form a receiving cavity for accommodating the drive motor 20.

[0082] Please refer to Figure 4, which shows a cross-sectional view of a powertrain 100 provided in an embodiment of this application. One of the two axial housings of the powertrain 100 includes an internal flow channel 124. For ease of description, in subsequent embodiments, a first axial housing 12 is defined as including an internal flow channel 124. In some embodiments, the first axial housing 12 may be located on the side of the motor stator 22 of the drive motor 20 away from the gear set of the reducer 103. That is, the internal flow channel 124 is located on the side of the drive motor 20 away from the reducer 103. In one embodiment, the first axial housing 12 is arranged axially along the motor shaft 211 on one side of the motor stator 22. The end face of the first axial housing 12 facing the motor stator 22 includes a bearing groove 123 and an axial protrusion 121. The bearing groove 123 is used to accommodate a motor bearing 30, which is used for drive connection to the motor shaft 211.

[0083] As shown in Figure 4, the first axial housing 12 of the housing 10 is located on the side of the motor shaft 211 away from the reducer 103. The first axial housing 12 is provided with a bearing groove 123 on the side facing the motor shaft 211. The bearing groove 123 is used to fix the outer ring of the motor bearing 30. The inner ring of the motor bearing 30 is connected to one end of the motor shaft 211. The inner ring and outer ring of the motor bearing 30 are rotatably connected to support the motor shaft 211.

[0084] The axial protrusion 121 of the powertrain 100 of this application is located within the bearing groove 123. One end of the axial protrusion 121 is used to fixally connect to the bottom of the bearing groove 123, and the other end of the axial protrusion 121 is used to extend into the shaft hole 212 of the motor shaft 211 along the axial direction of the motor shaft 211. The end face of the other end of the axial protrusion 121 includes a through hole 122, which is used to connect the internal flow channel 124 of the first axial housing 12 and the shaft hole 212 of the motor shaft 211.

[0085] As shown in Figure 4, the first axial housing 12 is provided with an internal flow channel 124, which extends radially along the motor shaft 211 and communicates with the through hole 122. The internal flow channel 124 is used to transport coolant or lubricating oil.

[0086] In one embodiment, the internal flow channel 124 of the first axial housing 12 extends axially along the motor shaft 211 and penetrates the first axial housing 12. Alternatively, the through hole 122 extends in a direction away from the motor shaft 211 and penetrates the housing 10. The through hole 122 is connected to an external oil supply line or an oil pump through the internal flow channel 124, so that lubricating oil or coolant flows sequentially through the internal flow channel 124 and the through hole 122 into the shaft hole 212 of the motor shaft 211.

[0087] Understandably, the coolant flows through the through hole 122 into the shaft hole 212 and absorbs heat to reduce the temperature of the drive motor 20; the lubricating oil can flow through the shaft hole 212 to the other end of the shaft hole 212, that is, the lubricating oil flows towards the reducer 103. After the lubricating oil flows to the reducer 103, it provides lubrication for the gear set inside the reducer, so as to reduce the wear generated by the gear set during meshing and improve the service life of the reducer 103.

[0088] It should be noted that, in one embodiment, the coolant and lubricating oil mentioned above can be the same type of liquid, which is used to cool the drive motor 20 during the process of passing through the shaft hole 212, and is used to lubricate the gear set of the reducer 103 after flowing to the reducer 103.

[0089] In one embodiment, the gap between the outer peripheral surface of the axial protrusion 121 of the powertrain 100 and the inner peripheral surface of the shaft hole 212 is used to accommodate the conductive structure 40, which is used to conduct the electrical connection between the outer peripheral surface of the axial protrusion 121 and the inner peripheral surface of the shaft hole 212.

[0090] Please refer to Figure 5, which shows a partially enlarged schematic diagram of the powertrain 100 provided in an embodiment of this application.

[0091] As shown in Figure 5, the conductive structure 40 is annular and is sleeved on the outside of the axial protrusion 121. The inner circumferential surface of the conductive structure 40 is at least partially in contact with the outer circumferential surface of the axial protrusion 121, and the outer circumferential surface of the conductive structure 40 is at least partially in contact with the inner circumferential surface of the shaft hole 212, so as to realize the electrical connection between the axial protrusion 121 and the shaft hole 212.

[0092] During the operation of the drive motor 20, the motor shaft 211 will generate shaft end current under the influence of the magnetic field generated by the motor stator 22. When the shaft end current flows through the motor bearing 30, it will cause local high temperature and corrosion, resulting in a shortened service life of the motor bearing 30. In addition, the shaft end current will also undergo an electrochemical reaction with the lubricating medium inside the motor bearing 30, reducing the lubrication effect of the lubricating medium and accelerating the wear of the motor bearing 30.

[0093] The powertrain 100 of this application conducts an electrical connection between the outer peripheral surface of the axial protrusion 121 and the inner peripheral surface of the shaft hole 212 through the conductive structure 40, so as to conduct the shaft end current of the motor shaft 211 to the housing 10 to achieve grounding, thereby preventing the shaft end current of the motor shaft 211 from flowing through the motor bearing 30 and causing the motor bearing 30 to fail.

[0094] Compared to the conductive structure of motor bearings in the prior art, the axial protrusion 121 of the powertrain 100 in this application extends into the shaft hole 212, and the conductive structure 40 is located inside the shaft hole 212. This fully utilizes the internal space of the motor shaft 211, making the axial dimension of the powertrain 100 along the motor shaft 211 smaller and the internal structure more compact. Compared to the prior art, the conductive structure 40 of the powertrain 100 in this application is located between the axial protrusion 121 and the shaft hole 212, which will not affect the flow of coolant or lubricating oil from the through hole 122 to the shaft hole 212, thus ensuring the cooling and lubrication requirements of the internal components of the powertrain 100.

[0095] Accordingly, the electric vehicle provided in this application embodiment adopts the above-mentioned powertrain 100, making the electric vehicle structure more compact and its service life longer.

[0096] In one embodiment, the axial bore 212 along the motor shaft 211 includes two sections, one section for accommodating the conductive structure 40, and the other end of the axial protrusion 121 for extending through the conductive structure 40 into the other section of the motor shaft 211. The gap between the outer peripheral surface of the axial protrusion 121 and the inner peripheral surface of one section is greater than the gap between the outer peripheral surface of the axial protrusion 121 and the inner peripheral surface of the other section along the radial direction of the motor shaft 211.

[0097] Please refer to Figure 6 for another partially enlarged schematic diagram of the powertrain 100 provided in an embodiment of this application.

[0098] As shown in Figure 6, the shaft hole 212 is divided into a first shaft hole section 2121 and a second shaft hole section 2122 along the axial direction of the motor shaft 211. The first shaft hole section 2121 is used to accommodate the conductive structure 40, and the second shaft hole section 2122 is used to accommodate part of the axial protrusion 121. The radial dimension of the first shaft hole section 2121 is larger than the radial dimension of the second shaft hole section 2122.

[0099] In the powertrain 100 shown in Figure 6, a first shaft hole section 2121 along the axial direction of the motor shaft 211 is located on the side of the second shaft hole section 2122 facing the bottom of the bearing groove 123. The first shaft hole section 2121 is used to accommodate the conductive structure 40, and the second shaft hole section 2122 is used to accommodate part of the axial protrusion 121. Along the radial direction of the motor shaft 211, the gap between the inner circumferential surface of the first shaft hole section 2121 and the outer circumferential surface of the axial protrusion 121 is greater than the gap between the inner circumferential surface of the second shaft hole section 2122 and the outer circumferential surface of the axial protrusion 121.

[0100] By dividing the shaft hole 212 of the motor shaft 211 into a first shaft hole segment 2121 and a second shaft hole segment 2122 with different inner diameters, two gaps with different radial dimensions are formed between the outer peripheral surface of the axial protrusion 121 and the inner peripheral surface of the shaft hole 212 along the axial direction of the motor shaft 211. The radial dimension of the gap in the first shaft hole segment 2121 is larger than that in the second shaft hole segment 2122. The gap in the first shaft hole segment 2121 is used to accommodate the conductive structure 40, while the axial protrusion 121 delivers coolant or lubricating oil towards the shaft hole 212 through the gap in the second shaft hole segment 2122. This ensures that the coolant or lubricating oil reliably enters the shaft hole 212 of the motor shaft 211 while providing sufficient installation space for the conductive structure 40.

[0101] In one embodiment, the two shaft holes 212 of the motor shaft 211 are used to form a stepped surface. The stepped surface faces the conductive structure 40 along the axial direction of the motor shaft 211, and the distance between the stepped surface and the conductive structure 40 is smaller than the distance between the bottom of the bearing groove 123 and the conductive structure 40.

[0102] As shown in Figure 6, the first shaft hole section 2121 and the second shaft hole section 2122 of the motor shaft 211 are used to form the first stepped surface 213. The first stepped surface 213 faces the conductive structure 40 along the axial direction of the motor shaft 211, and the distance between the first stepped surface 213 and the conductive structure 40 is smaller than the distance between the bottom of the bearing groove 123 and the conductive structure 40.

[0103] Understandably, the smaller the distance between the first step surface 213 along the axial direction of the motor shaft 211 and the conductive structure 40, the longer the length of the second shaft hole section 2122 extending into the shaft hole 212 of the axial protrusion 121. Because the radial dimension of the gap between the second shaft hole section 2122 of the shaft hole 212 and the axial protrusion 121 is small, the coolant or lubricating oil has to travel a longer distance from the second shaft hole section 2122 back to the first shaft hole section 2121, which can reduce the contact between the conductive structure 40 and the coolant or lubricating oil.

[0104] In one embodiment, the inner circumferential surface of a section of the axial bore 212 along the motor shaft 211 includes a mating section, and the conductive structure 40 is used to conduct electrical connection between the inner circumferential surface of the mating section and the outer circumferential surface of the axial protrusion 121. The inner diameter of the mating section is larger than the inner diameter of the remaining portion of the section of the bore 212 along the radial direction of the motor shaft 211.

[0105] Please refer to Figures 7 and 8, where Figure 7 is another exploded view of the powertrain 100 provided in an embodiment of this application, and Figure 8 is another cross-sectional view of the powertrain 100 provided in an embodiment of this application.

[0106] As shown in Figure 7, the inner circumferential surface of the first shaft hole segment 2121 of the axial shaft hole 212 along the motor shaft 211 includes a first mating segment 2124. The conductive structure 40 is used to conduct electrical connection between the inner circumferential surface of the first mating segment 2124 and the outer circumferential surface of the axial protrusion 121. Referring to Figure 8, along the radial direction of the motor shaft 211, the inner diameter of the first mating segment 2124 is larger than the inner diameter of the remaining portion of the first shaft hole segment 2121. The first mating segment 2124 is used to form a limiting groove on the inner circumferential surface of the shaft hole 212. The limiting groove is used to limit the displacement of the conductive structure 40 relative to the shaft hole 212 along the axial direction of the motor shaft 211, so as to ensure reliable contact between the conductive structure 40 and the inner circumferential surface of the shaft hole 212 and to achieve electrical connection.

[0107] In one embodiment, the length of the first mating segment 2124 along the axial direction of the motor shaft 211 is greater than or equal to the length of the conductive structure 40. The outer peripheral surface of the conductive structure 40 can be completely mated with the first mating segment 2124. The limiting groove completely accommodates the conductive structure 40 to limit the axial displacement of the conductive structure 40 along the motor shaft 211.

[0108] In one embodiment, the outer peripheral surface of the motor shaft 211 along the axial direction of the motor shaft 211 includes a first segment 2111 and a second segment 2112 connected together. The outer diameter of the first segment 2111 is smaller than the outer diameter of the second segment 2112 and greater than or equal to the inner diameter of the motor bearing 30 along the radial direction of the motor shaft 211.

[0109] As shown in Figure 8, along the axial direction of the motor shaft 211, the first segment 2111 is located on the side of the second segment 2112 facing the bottom of the bearing groove 123. The outer circumferential surface of the motor shaft 211 forms a second stepped surface 214 through the first segment 2111 and the second segment 2112. The second stepped surface 214 faces the bottom of the bearing groove 123 along the axial direction of the motor shaft 211. The second stepped surface 214 is used to abut against the side of the motor bearing 30 to limit the axial displacement of the motor bearing 30 relative to the motor shaft 211.

[0110] In one embodiment, along the axial direction of the motor shaft 211, the length of the first segment 2111 is greater than the length of a segment of the shaft hole 212. As shown in Figures 6 and 7, the length of the first segment 2111 along the axial direction of the motor shaft 211 is greater than the length of the first shaft hole segment 2121. Along the axial direction of the motor shaft 211, the second stepped surface 214 coincides with the second shaft hole segment 2122 of the shaft hole 212. That is, the second stepped surface 214 is located on the second shaft hole segment 2122 of the shaft hole 212 along the axial direction of the motor shaft 211, making the first segment 2111 larger in the radial direction of the motor shaft 211. This results in higher structural stability of the second stepped surface 214 within the motor shaft 211, better limiting the axial displacement of the motor bearing 30 relative to the motor shaft 211.

[0111] In one embodiment, along the axial direction of the motor shaft 211, the outer peripheral surface of the axial protrusion 121 includes another mating section, and the conductive structure 40 is used to conduct an electrical connection between the outer peripheral surface of the other mating section and the inner peripheral surface of the shaft hole 212. The outer diameter of the other mating section is smaller than the outer diameter of the remaining portion of the axial protrusion 121 along the radial direction of the motor shaft 211.

[0112] Please refer to Figure 9 for another exploded view of the powertrain 100 provided in an embodiment of this application.

[0113] As shown in Figures 6 and 9, along the axial direction of the motor shaft 211, the outer peripheral surface of the axial protrusion 121 includes a second mating section 1211. The second mating section 1211 is used to form a positioning groove 1212 on the outer peripheral surface of the axial protrusion 121. The positioning groove 1212 is used to limit the displacement of the conductive structure 40 relative to the axial protrusion 121 along the axial direction of the motor shaft 211, so as to ensure that the conductive structure 40 is in reliable contact with the outer peripheral surface of the axial protrusion 121 and realizes electrical connection.

[0114] In one embodiment, along the axial direction of the motor shaft 211, the length of another mating segment is greater than or equal to the length of the conductive structure 40. That is, the length of the second mating segment 1211 is greater than or equal to the length of the conductive structure 40. In the powertrain 100 shown in FIG8, the inner circumferential surface of the conductive structure 40 can be fully mated with the second mating segment 1211. The positioning groove 1212 fully accommodates the conductive structure 40 to limit the axial displacement of the conductive structure 40 along the motor shaft 211.

[0115] In one embodiment, the axial conductive structure 40 along the motor shaft 211 includes two opposite end faces, one of which is arranged between the other end face and the bottom of the bearing groove 123, and the distance between one end of the axial protrusion 121 and one end face is smaller than the distance between the other end of the axial protrusion 121 and the other end face.

[0116] Please refer to Figure 10, which shows another cross-sectional view of the powertrain 100 provided in an embodiment of this application.

[0117] As shown in Figure 10, the axial conductive structure 40 along the motor shaft 211 includes a first end face 401 and a second end face 402 facing away from each other. Referring to Figure 9, one of the first end face 401 and the second end face 402 is arranged between the other and the bottom of the bearing groove 123. For ease of description, in subsequent embodiments, the first end face 401 of the conductive structure 40 is defined as being arranged between the second end face 402 and the bottom of the bearing groove 123. In one embodiment, the second end face 402 of the conductive structure 40 is arranged between the first end face 401 and the bottom of the bearing groove 123.

[0118] Referring to Figures 5 and 10, the distance between the end of the axial protrusion 121 facing the bottom of the bearing groove 123 and the first end face 401 is less than the distance between the other end of the axial protrusion 121 and the second end face 402. The conductive structure 40 is closer to the bottom of the bearing groove 123 along the axial direction of the motor shaft 211, and farther from the grease nipple on the axial protrusion 121 that supplies coolant or lubricating oil. That is, the conductive structure 40 is closer to the bottom of the bearing groove 123 along the axial direction of the motor shaft 211. This reduces the contact between the conductive structure 40 and the coolant or lubricating oil, preventing premature failure due to excessive immersion in coolant or lubricating oil.

[0119] In one embodiment, the conductive structure 40 is annular. Along the radial direction of the motor shaft 211, the outer diameter of the conductive structure 40 is greater than or equal to the inner diameter of the shaft hole 212 of the motor shaft 211, and the inner diameter of the conductive structure 40 is less than or equal to the outer diameter of the axial protrusion 121.

[0120] In one embodiment, referring to Figures 7 and 8, the outer peripheral surface of the conductive structure 40 is in contact with the first mating section 2124, forming an electrical connection between the conductive structure 40 and the shaft hole 212. Referring to Figures 9 and 10, the inner peripheral surface of the conductive structure 40 is in contact with the second mating section 1211, forming an electrical connection between the conductive structure 40 and the axial protrusion 121. The conductive structure 40 undergoes elastic deformation to allow its outer peripheral surface to mat with the first mating section 2124 and its inner peripheral surface to mat with the second mating section 1211, thereby achieving an electrical connection between the conductive structure 40 and the shaft hole 212 and the axial protrusion 121.

[0121] Understandably, the outer peripheral surface of the conductive structure 40 forms an interference fit with the inner peripheral surface of the shaft hole 212 of the motor shaft 211, or the outer peripheral surface of the conductive structure 40 fits against the inner peripheral surface of the shaft hole 212 of the motor shaft 211 through elastic deformation, to ensure reliable contact and electrical connection between the conductive structure 40 and the shaft hole 212. Similarly, the inner peripheral surface of the conductive structure 40 forms an interference fit with the outer peripheral surface of the axial protrusion 121, or the inner peripheral surface of the conductive structure 40 fits against the outer peripheral surface of the axial protrusion 121 through elastic deformation, to ensure reliable connection and electrical connection between the conductive structure 40 and the axial protrusion 121.

[0122] Please refer to Figure 11, which is another exploded view of the powertrain 100 provided in an embodiment of this application.

[0123] In one embodiment, the conductive structure 40 includes an inner ring and an outer ring. The inner ring and the outer ring are sequentially fitted onto the outer peripheral surface of the axial protrusion 121 along the radial direction of the motor shaft 211, and the outer diameter of the inner ring is larger than the inner diameter of the outer ring.

[0124] In one embodiment, as shown in FIG11, the conductive structure 40 is composed of an inner ring and an outer ring nested together. The outer ring is a conductive bearing 42, and the inner ring is a conductive rubber ring 41. The outer circumferential surface of the inner ring is interference-fitted with the inner circumferential surface of the outer ring to ensure reliable electrical connection between the inner and outer rings.

[0125] In one embodiment, the outer peripheral surface of the inner ring of the conductive structure 40 abuts against the inner peripheral surface of the outer ring through elastic deformation, which can also ensure the reliability of the electrical connection between the inner ring and the outer ring.

[0126] In one embodiment, one of the inner ring and the outer ring is a conductive bearing 42, and the other is a conductive rubber ring 41.

[0127] As shown in Figures 10 and 11, the outer ring is a conductive bearing 42, and the inner ring is a conductive rubber ring 41. In one embodiment, the outer ring is a conductive rubber ring 41, and the inner ring is a conductive bearing 42.

[0128] Understandably, the conductive bearing 42 and the conductive rubber ring 41 have different stiffnesses. The conductive bearing 42 has higher stiffness, and the inner or outer ring formed by the conductive bearing 42 can improve the overall structural stability of the conductive structure 40. The conductive rubber ring 41 has lower stiffness, and the inner or outer ring formed by the conductive rubber ring 41 is used to offset the wear of the conductive structure 40 through elastic deformation to ensure reliable electrical connection. Furthermore, by differentiating the structure or material of the inner and outer rings, the conductive structure 40 can balance structural reliability and wear resistance.

[0129] In one embodiment, the length of the axial conductive rubber ring 41 along the motor shaft 211 is less than the length of the conductive bearing 42. The inner ring is the conductive bearing 42, and the gap between the portion of the outer circumference of the conductive bearing 42 extending beyond the conductive rubber ring 41 and a section of the shaft hole 212 is less than the gap between the other section of the shaft hole 212 and the other end of the axial protrusion 121.

[0130] Please refer to Figure 12 for another cross-sectional view of the powertrain 100 provided in an embodiment of this application.

[0131] As shown in Figure 12, the outer ring of the conductive structure 40 is a conductive rubber ring 41, and the inner ring is a conductive bearing 42. Along the axial direction of the motor shaft 211, the size of the conductive bearing 42 is larger than the size of the conductive rubber ring 41. That is, the outer peripheral surface of the conductive bearing 42 is exposed to the outside of the conductive rubber ring 41. The gap between the exposed outer peripheral surface of the conductive bearing 42 and the inner peripheral surface of the first shaft hole section 2121 of the shaft hole 212 along the radial direction of the motor shaft 211 is the second dimension L2. The gap between the inner peripheral surface of the second shaft hole section 2122 of the shaft hole 212 and the outer peripheral surface of the axial protrusion 121 along the radial direction of the motor shaft 211 is the first dimension L1.

[0132] The second dimension L2 is smaller than the first dimension L1. The radial movement of the motor shaft 211 causes the exposed outer peripheral surface of the conductive bearing 42 to abut against the first shaft hole section 2121 of the shaft hole 212, thereby limiting the radial displacement of the motor shaft 211 relative to the axial protrusion 121 and preventing the second shaft hole section 2122 from contacting the axial protrusion 121.

[0133] In one embodiment, the outer ring is a conductive bearing 42, and the gap between the portion of the inner circumferential surface of the conductive bearing 42 that extends beyond the conductive rubber ring 41 and the axial protrusion 121 is smaller than the gap between the other part of the shaft hole 212 and the other end of the axial protrusion 121.

[0134] Please refer to Figure 13 for another cross-sectional view of the powertrain 100 provided in an embodiment of this application.

[0135] As shown in Figure 13, the inner ring of the conductive structure 40 is a conductive rubber ring 41, and the outer ring is a conductive bearing 42. Along the axial direction of the motor shaft 211, the size of the conductive bearing 42 is larger than the size of the conductive rubber ring 41. That is, the inner circumferential surface of the conductive bearing 42 protrudes to the outside of the conductive rubber ring 41. The gap between the exposed inner circumferential surface of the conductive bearing 42 and the outer circumferential surface of the axial protrusion 121 along the radial direction of the motor shaft 211 is the third dimension L3.

[0136] The third dimension L3 is smaller than the first dimension L1. Correspondingly, the radial movement of the motor shaft 211 causes the exposed inner circumferential surface of the conductive bearing 42 to abut against the axial protrusion 121, thereby limiting the radial displacement of the motor shaft 211 relative to the axial protrusion 121 and preventing the second shaft hole section 2122 from contacting the axial protrusion 121.

[0137] Understandably, the conductive bearing 42 has high rigidity. When the motor shaft 211 moves radially, the portion of the conductive bearing 42 that extends beyond the conductive rubber ring 41 abuts against the outer circumferential surface of the axial protrusion 121 or the inner circumferential surface of the shaft hole 212. This prevents the axial protrusion 121 from contacting the second shaft hole section 2122 of the shaft hole 212, and prevents the axial protrusion 121 from being deformed by collision, thus affecting the delivery of coolant or lubricating oil toward the shaft hole 212.

[0138] In one embodiment, there are two conductive rubber rings 41. The two conductive rubber rings 41 are arranged at intervals along the axial direction of the motor shaft 211, and the sum of the distance between the two conductive rubber rings 41 and the length of the two conductive rubber rings 41 is less than or equal to the length of the conductive bearing 42.

[0139] Please refer to Figure 14 for another cross-sectional view of the powertrain 100 provided in an embodiment of this application.

[0140] As shown in Figure 14, the conductive structure 40 includes a first conductive rubber ring 411 and a second conductive rubber ring 412. The first conductive rubber ring 411 and the second conductive rubber ring 412 are arranged at intervals along the axial direction of the motor shaft 211 to form the inner ring of the conductive structure 40. The two conductive rubber rings 41, which are spaced apart along the axial direction of the motor shaft 211, can distribute the impact force of the radial movement of the motor shaft 211 more evenly to the conductive bearing 42, thereby improving the internal stress conditions of the conductive structure 40 and extending the service life of the conductive structure 40.

[0141] In one embodiment, the elastic modulus of one of the two conductive rubber rings 41 is greater than that of the other conductive rubber ring 41. As shown in FIG14, the conductive rubber ring 41 includes a first conductive rubber ring 411 and a second conductive rubber ring 412. The elastic modulus of the first conductive rubber ring 411 is greater than that of the second conductive rubber ring 412. By setting the elastic modulus of the materials of the two conductive rubber rings 41 differently, the elastic force of the two conductive rubber rings 41 along the radial direction of the motor shaft 211 can be differentiated. After long-term operation of the powertrain 100 of this application, the wear of the two conductive rubber rings 41 is different. The conductive rubber ring 41 with less wear can compensate for the wear of the other conductive rubber ring 41 through elastic deformation.

[0142] In one embodiment, a conductive rubber ring 41 is arranged along the axial direction of the motor shaft 211 between another conductive rubber ring 41 and the bottom of the bearing groove 123.

[0143] Please refer to Figure 15 for another cross-sectional view of the powertrain 100 provided in an embodiment of this application.

[0144] As shown in Figure 15, the second conductive rubber ring 412 is located on the side of the first conductive rubber ring 411 away from the bottom of the bearing groove 123 along the axial direction of the motor shaft 211. That is, compared with the first conductive rubber ring 411, the second conductive rubber ring 412 is closer to the second shaft hole section 2122 of the shaft hole 212. The radial movement of the motor shaft 211 results in a greater compression of the second conductive rubber ring 412, thereby forming a certain sealing effect on the first conductive rubber ring 411, reducing the contact between the first conductive rubber ring 411 and the coolant or lubricating oil, and protecting the first conductive rubber ring 411.

[0145] In one embodiment, the inner ring is a conductive bearing 42, and the gap between the outer peripheral surface of the conductive bearing 42 located between the two conductive rubber rings 41 along the axial direction of the motor shaft 211 and the inner peripheral surface of the shaft hole 212 is smaller than the gap between the other part of the shaft hole 212 and the other end of the axial protrusion 121.

[0146] As shown in Figure 15, the inner ring of the conductive structure 40 is a conductive bearing 42, and the outer ring consists of a first conductive rubber ring 411 and a second conductive rubber ring 412 arranged at intervals. Along the axial direction of the motor shaft 211, the sum of the distance between the first conductive rubber ring 411 and the second conductive rubber ring 412, the size of the first conductive rubber ring 411, and the size of the second conductive rubber ring 412 is less than the size of the conductive bearing 42. That is, the outer peripheral surface of the conductive bearing 42 is exposed to the outside of the first conductive rubber ring 411 and the second conductive rubber ring 412. The gap between the exposed outer peripheral surface of the conductive bearing 42 and the inner peripheral surface of the first shaft hole section 2121 of the shaft hole 212 along the radial direction of the motor shaft 211 is the fourth dimension L4.

[0147] The fourth dimension L4 is smaller than the first dimension L1. Accordingly, the radial movement of the motor shaft 211 causes the exposed outer peripheral surface of the conductive bearing 42 to abut against the first shaft hole section 2121 of the shaft hole 212, thereby limiting the radial displacement of the motor shaft 211 relative to the axial protrusion 121 and preventing the second shaft hole section 2122 from contacting the axial protrusion 121.

[0148] In one embodiment, the outer ring is a conductive bearing 42, and the gap between the inner circumferential surface of the conductive bearing 42 located between the two conductive rubber rings 41 along the axial direction of the motor shaft 211 and the outer circumferential surface of the axial protrusion 121 is smaller than the gap between the other part of the shaft hole 212 and the other end of the axial protrusion 121.

[0149] Please refer to Figure 16 for another cross-sectional view of the powertrain 100 provided in an embodiment of this application.

[0150] As shown in Figure 16, the inner ring of the conductive structure 40 consists of a first conductive rubber ring 411 and a second conductive rubber ring 412 arranged at intervals, and the outer ring is a conductive bearing 42. Along the axial direction of the motor shaft 211, the sum of the distance between the first conductive rubber ring 411 and the second conductive rubber ring 412, the size of the first conductive rubber ring 411, and the size of the second conductive rubber ring 412 is less than the size of the conductive bearing 42. That is, the inner circumferential surface of the conductive bearing 42 is exposed to the outside of the first conductive rubber ring 411 and the second conductive rubber ring 412. The gap between the exposed inner circumferential surface of the conductive bearing 42 and the outer circumferential surface of the axial protrusion 121 along the radial direction of the motor shaft 211 is the fifth dimension L5.

[0151] The fifth dimension L5 is smaller than the first dimension L1. Accordingly, the motor shaft 211 moves radially, causing the exposed inner circumferential surface of the conductive bearing 42 to abut against the axial protrusion 121, thereby limiting the radial displacement of the motor shaft 211 relative to the axial protrusion 121 and preventing the second shaft hole section 2122 from contacting the axial protrusion 121.

[0152] Understandably, the conductive bearing 42 has high rigidity. When the motor shaft 211 moves radially, the part of the conductive bearing 42 located between the two conductive rubber rings 41 abuts against the outer circumferential surface of the axial protrusion 121 or the inner circumferential surface of the shaft hole 212. This prevents the axial protrusion 121 from contacting the second shaft hole section 2122 of the shaft hole 212, and prevents the axial protrusion 121 from being deformed by collision and affecting the delivery of coolant or lubricating oil toward the shaft hole 212.

[0153] In one embodiment, the conductive structure 40 includes an axial sleeve 43. The conductive structure 40 is fixed to the outer peripheral surface of the axial protrusion 121 by the axial sleeve 43, and the outer peripheral surface of the conductive structure 40 is used to coat a wear-resistant conductive coating.

[0154] Please refer to Figure 17 for another cross-sectional view of the powertrain 100 provided in an embodiment of this application.

[0155] As shown in Figure 17, the axial sleeve 43 extends axially along the motor shaft 211 to increase the contact area between the conductive structure 40 and the axial protrusion 121, thereby fixing the conductive structure 40 to the outer peripheral surface of the axial protrusion 121. During the operation of the drive motor 20, the motor shaft 211 rotates within the housing 10, and the inner peripheral surface of the shaft hole 212 of the motor shaft 211 continuously rotates and rubs against the outer peripheral surface of the conductive structure 40. The wear-resistant conductive coating applied to the outer peripheral surface of the conductive structure 40 reduces wear on the outer peripheral surface of the conductive structure 40 and conducts electrical connection between the outer peripheral surface of the conductive structure 40 and the inner peripheral surface of the shaft hole 212 of the motor shaft 211.

[0156] In one embodiment, the conductive structure 40 is fixed to the inner circumferential surface of the shaft hole 212 by an axial sleeve 43. The inner circumferential surface of the conductive structure 40 is coated with a wear-resistant conductive coating. Referring to Figure 17, the axial sleeve 43 extends axially along the motor shaft 211 to increase the contact area between the conductive structure 40 and the shaft hole 212 of the motor shaft 211, thereby fixing the conductive structure 40 to the inner circumferential surface of the shaft hole 212 of the motor shaft 211. During the operation of the drive motor 20, the conductive structure 40 rotates with the motor shaft 211 within the housing 10, and the inner circumferential surface of the conductive structure 40 continuously rotates and rubs against the outer circumferential surface of the axial protrusion 121. The wear-resistant conductive coating on the inner circumferential surface of the conductive structure 40 reduces wear on the inner circumferential surface of the conductive structure 40 and establishes an electrical connection between the inner circumferential surface of the conductive structure 40 and the outer circumferential surface of the axial protrusion 121.

[0157] In one embodiment, the conductive structure 40 includes a radial protrusion 44, which conducts an electrical connection between the outer peripheral surface of the axial protrusion 121 and the inner peripheral surface of the shaft hole 212. The radial protrusion 44 is used to fix one end of the axial sleeve 43 near the bottom of the bearing groove 123 along the axial direction of the motor shaft 211.

[0158] Figure 18 is another schematic diagram of the powertrain 100 provided in the embodiment of this application; Figure 19 is another cross-sectional schematic diagram of the powertrain 100 provided in this application.

[0159] As shown in Figures 18 and 19, the radial protrusion 44 is located on the side of the axial sleeve 43 away from the second shaft hole section 2122. The radial protrusion 44 conducts electrical connection between the inner circumferential surface of the shaft hole 212 and the outer circumferential surface of the axial protrusion 121 on the side near the bottom of the bearing groove 123, reducing the contact between the radial protrusion 44 and the coolant or lubricating oil to extend the service life of the conductive structure 40.

[0160] In one embodiment, the axial sleeve 43 is fixed to the outer peripheral surface of the axial protrusion 121, and the radial protrusion 44 extends toward and contacts the inner peripheral surface of the shaft hole 212 to achieve electrical connection between the outer peripheral surface of the axial protrusion 121 and the inner peripheral surface of the shaft hole 212. Further, in one embodiment, the side of the radial protrusion 44 facing the inner peripheral surface of the shaft hole 212 is coated with a wear-resistant conductive coating to reduce wear on the radial protrusion 44.

[0161] In one embodiment, the radial protrusion 44 includes multiple rolled edges, which are fixed around and spaced apart from the end of the radial protrusion 44 away from the axial sleeve 43. When the axial sleeve 43 is fixed to the outer peripheral surface of the axial protrusion 121, the multiple rolled edges abut against the inner peripheral surface of the first shaft hole section 2121. It is understood that the rolled edges are elastic, and when the conductive structure 40 is installed in the gap between the axial protrusion 121 and the shaft hole 212, the rolled edges undergo a certain elastic deformation towards the axial sleeve 43. The elasticity of the rolled edges can compensate for wear, preventing gaps between the rolled edges and the inner peripheral surface of the first shaft hole section 2121, thus ensuring reliable electrical connection. Furthermore, the side of the multiple rolled edges facing the inner peripheral surface of the shaft hole 212 can also be coated with a wear-resistant conductive coating to reduce wear on the rolled edges.

[0162] In one embodiment, the axial sleeve 43 is fixed to the inner circumferential surface of the shaft hole 212, and the radial protrusion 44 extends toward and contacts the outer circumferential surface of the axial protrusion 121 to achieve electrical connection between the outer circumferential surface of the axial protrusion 121 and the inner circumferential surface of the shaft hole 212. Further, in one embodiment, the side of the radial protrusion 44 facing the outer circumferential surface of the axial protrusion 121 is coated with a wear-resistant conductive coating to reduce wear on the radial protrusion 44.

[0163] Correspondingly, the radial protrusion 44 may also include multiple rolled edges, i.e., the axial sleeve 43 is fixed to the inner circumferential surface of the shaft hole 212, and the multiple rolled edges abut against the outer circumferential surface of the axial protrusion 121. Similarly, the elasticity of the rolled edges can also compensate for wear and prevent gaps from forming between the rolled edges and the outer circumferential surface of the axial protrusion 121, so as to ensure reliable electrical connection. Furthermore, the side of the multiple rolled edges facing the outer circumferential surface of the axial protrusion 121 may also be coated with a wear-resistant conductive coating to reduce wear on the rolled edges.

[0164] In one embodiment, the axial sleeve 43 is engaged and fixed with the radial protrusion 44 to form a conductive structure 40. In another embodiment, the axial sleeve 43 and the radial protrusion 44 are integrally stamped to improve the structural strength of the conductive structure 40 and reduce the assembly steps of the powertrain 100.

[0165] In one embodiment, along the axial direction of the motor shaft 211, the axial sleeve 43 extends toward the bottom of the groove away from the bearing groove 123.

[0166] As shown in Figures 18 and 19, along the axial direction of the motor shaft 211, the axial sleeve 43 is positioned relative to the second shaft hole section 2122, which is close to the shaft hole 212 of the motor shaft 211. A radial protrusion 44, on the side near the bottom of the bearing groove 123, electrically connects the inner circumferential surface of the shaft hole 212 to the outer circumferential surface of the axial protrusion 121. The radial protrusion 44 is positioned relative to the second shaft hole section 2122, which is farther from the shaft hole 212, reducing contact between the radial protrusion 44 and the coolant or lubricating oil to extend the service life of the conductive structure 40.

[0167] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the scope of protection of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A powertrain protected against bearing electric corrosion, characterized in that, The powertrain housing houses a drive motor, which includes a motor shaft and a motor stator. The motor shaft drives wheels via a reducer. The housing includes an axial housing arranged axially along the motor shaft on one side of the motor stator. The end face of the axial housing facing the motor stator includes a bearing groove and an axial protrusion. The bearing groove houses a motor bearing for drive connection to the motor shaft. One end of the axial protrusion is fixedly connected to the bottom of the bearing groove, and the other end of the axial protrusion extends axially into the shaft hole of the motor shaft. The end face of the other end of the axial protrusion includes a through hole for connecting the internal flow channel of the axial housing and the shaft hole of the motor shaft. The gap between the outer peripheral surface of the axially protruding part and the inner peripheral surface of the shaft hole is used to accommodate a conductive structure, which is used to conduct electrical connection between the outer peripheral surface of the axially protruding part and the inner peripheral surface of the shaft hole.

2. The powertrain of claim 1, wherein, The shaft hole along the axial direction of the motor shaft includes two sections, one section for accommodating the conductive structure, and the other end of the axial protrusion for extending through the conductive structure into the other section of the motor shaft, wherein: Along the radial direction of the motor shaft, the gap between the outer peripheral surface of the axially protruding section and the inner peripheral surface of the segment is greater than the gap between the outer peripheral surface of the axially protruding section and the inner peripheral surface of the other segment.

3. The powertrain of claim 2, wherein, The conductive structure along the axial direction of the motor shaft includes two opposite end faces, one end face being arranged between the other end face and the bottom of the bearing groove, and the distance between one end of the axial protrusion and the one end face is smaller than the distance between the other end of the axial protrusion and the other end face.

4. The powertrain of claim 2 or 3, wherein, Along the axial direction of the motor shaft, the outer peripheral surface of the axially protruding part includes a mating section, and the conductive structure is used to conduct an electrical connection between the outer peripheral surface of the mating section and the inner peripheral surface of the shaft hole, wherein: Along the radial direction of the motor shaft, the outer diameter of the mating section is smaller than the outer diameter of the remaining portion of the axial protrusion; Along the axial direction of the motor shaft, the length of the mating segment is greater than or equal to the length of the conductive structure.

5. The powertrain of any one of claims 2-4, wherein, The two shaft holes of the motor shaft are used to form a stepped surface, and the stepped surface faces the conductive structure along the axial direction of the motor shaft. The distance between the stepped surface and the conductive structure is less than the distance between the bottom of the bearing groove and the conductive structure.

6. The powertrain of any one of claims 2-5, wherein, The inner circumferential surface of a portion of the shaft hole along the axial direction of the motor shaft includes another mating section, and the conductive structure is used to conduct an electrical connection between the inner circumferential surface of the other mating section and the outer circumferential surface of the axially protruding section, wherein: Along the radial direction of one motor shaft, the inner diameter of the other mating section is larger than the inner diameter of a portion of the remaining part of the shaft hole; Along the axial direction of the motor shaft, the length of the other mating segment is greater than or equal to the length of the conductive structure.

7. The powertrain of any one of claims 2-6, wherein, Along the axial direction of the motor shaft, the outer peripheral surface of the motor shaft includes a first segment and a second segment connected together, wherein: Along the radial direction of the motor shaft, the outer diameter of the first segment is smaller than the outer diameter of the second segment and greater than or equal to the inner diameter of the motor bearing; Along the axial direction of the motor shaft, the length of the first segment is greater than the length of a segment of the shaft hole.

8. The powertrain of any one of claims 1-7, wherein, The conductive structure is ring-shaped, wherein: Along the radial direction of the motor shaft, the outer diameter of the conductive structure is greater than or equal to the inner diameter of the shaft hole of the motor shaft, and the inner diameter of the conductive structure is less than or equal to the outer diameter of the axial protrusion.

9. The powertrain of claim 8, wherein, The conductive structure includes an axial sleeve, wherein: The conductive structure is fixed to the outer peripheral surface of the axially protruding part by the axial sleeve, and the outer peripheral surface of the conductive structure is used to coat a wear-resistant conductive coating; or... The conductive structure is fixed to the inner circumferential surface of the shaft hole by the axial sleeve, and the inner circumferential surface of the conductive structure is used to coat a wear-resistant conductive coating.

10. The powertrain of claim 9, wherein, Along the axial direction of the motor shaft, the axial sleeve extends toward the bottom of the bearing groove away from the groove.

11. The powertrain of claim 8, wherein, The conductive structure includes an inner ring and an outer ring, wherein: An inner ring and an outer ring are sequentially fitted onto the outer circumferential surface of an axially protruding part along the radial direction of the motor shaft, wherein the outer diameter of the inner ring is larger than the inner diameter of the outer ring. One of the inner ring and the other of the outer ring is a conductive bearing, and the other is a conductive rubber ring.

12. The powertrain of claim 11, wherein, The length of the conductive rubber ring along the axial direction of the motor shaft is less than the length of the conductive bearing, wherein: The inner ring is the conductive bearing, and the gap between the portion of the outer circumference of the conductive bearing extending beyond the conductive rubber ring and a section of the shaft hole is smaller than the gap between the other section of the shaft hole and the other end of the axial protrusion; or... The outer ring is the conductive bearing, and the gap between the portion of the inner circumferential surface of the conductive bearing that extends beyond the conductive rubber ring and the axial protrusion is smaller than the gap between the other section of the shaft hole and the other end of the axial protrusion.

13. The powertrain of claim 11 or 12, wherein, The number of conductive rubber rings is two, wherein: Along the axial direction of the motor shaft, two conductive rubber rings are arranged at intervals, and the sum of the distance between the two conductive rubber rings and the length of the two conductive rubber rings is less than or equal to the length of the conductive bearing.

14. The powertrain of claim 13, wherein, One of the two conductive rubber rings has a greater elastic modulus than the other conductive rubber ring, and the conductive rubber ring is arranged between the other conductive rubber ring and the bottom of the bearing groove along the axial direction of the motor shaft.

15. An electric vehicle characterized by comprising: The electric vehicle includes wheels and a powertrain as described in any one of claims 1-14, the powertrain being used to drive the wheels of the electric vehicle.

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