Power assembly and electric vehicle

Abstract

The invention provides a power assembly and an electric vehicle, and relates to the technical field of electric vehicles. The power assembly comprises a driving motor, a speed reducer and an adapter shaft. The driving motor is used for driving the coupling shaft through the speed reducer. The coupling shaft penetrates through a motor shaft of the driving motor, and the end, extending out of the motor shaft, of the coupling shaft is in transmission connection with one wheel of the electric vehicle. The adapter shaft comprises a through hole, a first section and a second section. The first section and the second section are adjacently arranged in the axial direction of the adapter shaft, the through hole penetrates through the second section, the extending direction of the through hole intersects with the axial direction of the adapter shaft, and the through hole is used for communicating with a shaft cavity of the second section. Due to the fact that the second section is prone to stress concentration, based on the adjacent arrangement position relation of the first section and the second section, by adjusting the radial thickness of the first section to be smaller than the radial thickness of the second section, the change amplitude of the rigidity of the adapter shaft from the second section to the first section is reduced, and the control over the stress concentration degree around the through hole is facilitated.

Description

Technical Field

[0001] This application relates to the field of electric vehicle technology, and in particular to a powertrain and an electric vehicle. Background Technology

[0002] The powertrain is the primary power source for new energy vehicles. With the continuous development of the new energy vehicle industry, the requirements for the safety performance of the powertrain are becoming increasingly stringent. Excessive localized stress in the powertrain may damage its service life and structural strength, thereby affecting driving safety. Summary of the Invention

[0003] This application provides a powertrain and electric vehicle that can alleviate stress concentration and improve safety performance.

[0004] In a first aspect, embodiments of this application provide a powertrain including a drive motor, a reducer, and an adapter shaft. The drive motor drives the adapter shaft via the reducer. The adapter shaft passes through the motor shaft of the drive motor, and one end of the adapter shaft extends out of the motor shaft for power transmission connection to one wheel of an electric vehicle.

[0005] The adapter shaft includes a through hole, a first section, and a second section, which are arranged adjacent to each other along the axial direction of the adapter shaft. The through hole extends through the second section, and its extension direction intersects the axial direction of the adapter shaft. The through hole is used to connect the shaft cavity of the first section through the shaft cavity of the second section. The distance between the outer and inner circumferential surfaces of the first section along the radial direction of the adapter shaft is less than the distance between the outer and inner circumferential surfaces of the second section.

[0006] In this embodiment, the adapter shaft passes through the motor shaft and has a transmission relationship with the reducer and wheels, respectively. Based on the distribution characteristics of the adapter shaft in the powertrain, in addition to transmitting power, the adapter shaft can also serve as a component of the cooling and lubrication system in the powertrain. Utilizing the adapter shaft to hold and transmit oil facilitates the flow of oil to areas in the powertrain that require cooling or lubrication, thereby improving the oil transmission efficiency.

[0007] To enable the adapter shaft to guide and distribute oil, through holes need to be created on it. However, through holes reduce the structural strength of the adapter shaft. Machining through holes on the adapter shaft requires removing some material, disrupting the continuous cross-section and leading to localized stress concentration. Furthermore, the oil flow rate of the through hole is related to its diameter. Reducing the diameter to alleviate stress concentration would make it difficult for the through hole to meet the cooling and lubrication requirements of the powertrain.

[0008] To balance the structural strength of the adapter shaft with the oil flow efficiency of the through-hole, one possible solution is to increase the thickness of the adapter shaft. However, increasing the thickness of the adapter shaft means increasing the radial dimension. To avoid interference, the radial dimensions of the structures arranged radially with the adapter shaft also need to be adjusted accordingly, leading to increased cost and weight of the powertrain. This is detrimental to achieving miniaturization and lightweight design of the powertrain and also increases the difficulty of powertrain layout in the overall vehicle.

[0009] This application embodiment comprehensively considers the structural strength, oil flow efficiency, and volume of the adapter shaft. By optimizing the axial stiffness variation of the adapter shaft, it is beneficial to alleviate the degree of local stress concentration in the adapter shaft without reducing the diameter of the through hole or increasing the overall radial dimension of the adapter shaft.

[0010] Specifically, the adapter shaft includes a first segment and a second segment arranged adjacent to each other. Through-holes for transmitting oil are distributed in the second segment. These through-holes penetrate the second segment, facilitating the receiving or output of oil. The through-holes alter the continuity of the adapter shaft's cross-section, resulting in a decrease in the stiffness of the second segment. If the radial thickness of the first segment is equal to that of the second segment, the change in stiffness from the first segment to the second segment is significant, exacerbating stress concentration at the through-hole. Therefore, in this embodiment, the radial thickness of the first segment is adjusted to be less than that of the second segment. Since the first and second segments are arranged adjacent to each other, reducing the radial thickness of the first segment shortens the stiffness difference between the two segments, reducing the abrupt change in stiffness at the through-hole and alleviating stress concentration around it. Shortening the local thickness of the adapter shaft also helps reduce its weight and moment of inertia.

[0011] The embodiments of this application improve the structural reliability and service life of the adapter shaft without interfering with the transmission of oil through the through hole, which helps to enhance the safety performance of the powertrain and electric vehicles.

[0012] In one embodiment, the extension direction of the through hole is parallel to the radial direction of the adapter shaft. This embodiment of the application helps reduce the machining difficulty of the through hole and shortens the flow path of the oil within it.

[0013] In one embodiment, the extension direction of the through hole intersects the radial direction of the adapter shaft. By adjusting the extension direction of the through hole, the opening of the through hole can avoid obstruction from other structures in the adapter shaft, reducing the risk of oil blockage.

[0014] In one embodiment, the length of the first segment along the axial direction of the adapter shaft is greater than the length of the second segment.

[0015] In this embodiment, the axial length of the first segment is related to the stiffness distribution of the adapter shaft. By adjusting the relationship between the axial lengths of the first and second segments, the effect of the first segment in adjusting the stiffness variation of the adapter shaft can be improved, avoiding the exacerbation of stress concentration due to abrupt changes in stiffness. Since the radial thickness of the second segment is greater than that of the first segment, controlling the axial length of the second segment helps to reduce the cost and weight of the adapter shaft.

[0016] In one embodiment, the length of the second segment along the axial direction of the adapter shaft is greater than the length of the through hole.

[0017] In this embodiment, the through hole extends radially through the second section of the adapter shaft, and the second section provides a stress dispersion path for the through hole. By adjusting the axial length relationship between the second section and the through hole, the stress dispersion effect of the second section can be enhanced, the stress concentration in the through hole can be reduced, thereby improving the structural strength of the adapter shaft.

[0018] In this embodiment, the axial length of the second segment is greater than the axial length of the through hole and less than the axial length of the first segment, which can balance the effect of stress dispersion with the cost and weight of the adapter shaft.

[0019] In one embodiment, the distance between the first segment along the axial direction of the adapter shaft and the through hole is less than the length of the through hole.

[0020] In this embodiment, because the radial thickness of the second segment is relatively large, if the axial distance between the first segment and the through hole is too large, it can easily exacerbate the abrupt change in the stiffness of the second segment. This embodiment reduces the axial distance between the first segment and the through hole, adjusting the layout of the through hole in the second segment, which helps to reduce the difficulty of adjusting the stiffness change of the first segment.

[0021] In one embodiment, the second segment includes a first portion and a second portion, with a through hole penetrating the first portion, and the second portion located between the first portion and the first segment along the axial direction of the adapter shaft. The distance between the outer and inner circumferential surfaces of the second portion decreases along the axial direction of the adapter shaft from the first portion toward the first segment.

[0022] In this embodiment, the radial thickness of the second segment is greater than that of the first segment. Using the first and second portions to adjust the radial thickness of the second segment avoids abrupt changes in its radial thickness relative to the first segment. The second portion also acts as a transitional element to adjust stiffness changes, reducing the risk of stress concentration at the connection between the first and second segments.

[0023] In one embodiment, the ratio of the radial outer diameter of the second segment along the adapter shaft to the axial diameter of the through hole along the adapter shaft is greater than or equal to 5 and less than or equal to 15. In this embodiment, the diameter of the through hole affects the degree of stress concentration and the oil flow rate. By adjusting the ratio of the outer diameter of the second segment to the diameter of the through hole, this embodiment facilitates the dispersion of some of the stress around the through hole using the second segment, thus ensuring that the diameter of the through hole meets the oil flow rate requirements.

[0024] In one embodiment, the adapter shaft includes a plurality of first segments and a plurality of second segments, with each second segment distributed between two first segments along the axial direction of the adapter shaft.

[0025] In this embodiment, two second segments are distributed on both sides of each first segment along the axial direction of the adapter shaft. By adjusting the arrangement of the first and second segments, the stiffness variation on different sides of the through hole can be adjusted using the two first segments, thereby reducing the degree of stress concentration around the through hole.

[0026] In this embodiment, each first segment is distributed between two second segments, indicating that the second segments are not located at the end of the adapter shaft. This facilitates the avoidance of the through hole from the high-stress area of ​​the adapter shaft used for power transmission, thus preventing stress from the through hole from interfering with the transmission of the adapter shaft.

[0027] In one embodiment, the adapter shaft includes a plurality of through holes, with one through hole and another through hole spaced apart along the axial direction of the adapter shaft. Along the axial direction of the adapter shaft, the length of one through hole is less than the length of the other through hole, and the outer diameter of a second segment penetrated by one through hole is less than or equal to the outer diameter of a second segment penetrated by the other through hole.

[0028] In this embodiment, the diameter of the through hole affects the oil flow rate, and the powertrain has different oil flow rate requirements for different through holes. When the through hole diameter is large, the radial thickness of the second section can be appropriately increased to compensate for some of the impact of the through hole on the structural strength of the first section. When the through hole diameter is small, the radial thickness of the second section can be appropriately reduced to decrease the cost of the adapter shaft.

[0029] In one embodiment, a first segment and a second segment of the adapter shaft are distributed on the inner circumferential side of the motor shaft, and the first segment and the second segment are adjacent to each other along the axial direction of the adapter shaft. The distance between the outer circumferential surface of the first segment and the inner circumferential surface of the motor shaft is greater than the distance between the outer circumferential surface of the second segment and the inner circumferential surface of the motor shaft along the radial direction of the adapter shaft.

[0030] In this embodiment, a second segment is distributed on the inner circumference of the motor shaft, and the through hole of the second segment can transmit oil to the gap between the adapter shaft and the motor shaft. Exemplarily, after the oil flows into the gap between the adapter shaft and the motor shaft, it can flow into the rotor oil passage of the motor rotor through the motor shaft, thereby cooling the motor rotor. A first segment and a second segment are arranged adjacent to each other, and the outer circumferential surface of the first segment can participate in forming part of the gap between the adapter shaft and the motor shaft. To ensure that the radial thickness of the first segment is less than the radial thickness of the second segment, and to reduce the flow resistance of the oil, this embodiment adjusts the outer diameter of the first segment to be smaller than the outer diameter of the second segment. By reducing the outer diameter of the first segment, not only can the stiffness change from one first segment to the second segment be reduced, alleviating the stress concentration in the second segment, but the space between the first segment and the inner circumferential surface of the motor shaft can also be increased, which is beneficial to improving the oil transmission efficiency.

[0031] In the embodiments of this application, from the perspective of powertrain layout, by adjusting the outer diameter of a first segment and reducing the radial space occupied by the first segment, it is possible to avoid adapting the adapter shaft by increasing the inner diameter of the motor shaft and motor rotor, which helps to miniaturize the powertrain design and reduces the difficulty of powertrain layout in the vehicle.

[0032] In one embodiment, a through hole is used to transmit oil to the gap between the adapter shaft and the motor shaft, with the other end of the adapter shaft extending from one end face of the motor shaft.

[0033] The inner circumferential surface of the motor shaft includes an oil-blocking protrusion that protrudes towards a first section. The oil-blocking protrusion is distributed between a second section and one end face of the motor shaft.

[0034] In this embodiment, the other end of the adapter shaft extends from the motor shaft. Oil flowing between the adapter shaft and the motor shaft tends to flow towards the end of the motor shaft under centrifugal force, easily leading to oil leakage. To improve oil utilization, this embodiment utilizes an oil-blocking protrusion to form a stepped structure between the adapter shaft and the motor shaft, controlling oil flow and preventing excessive oil accumulation at the end of the motor shaft. A first section with a relatively small outer diameter provides space for the oil-blocking protrusion on the inner circumference of the motor shaft. The oil-blocking protrusion is distributed between a second section and one end face of the motor shaft, reducing the risk of oil leakage while achieving proper alignment between the oil-blocking protrusion and the through-hole. This facilitates stable oil flow within the shaft cavity of the adapter shaft and the gap between the adapter shaft and the motor shaft.

[0035] In one embodiment, the ratio of the outer diameter of a first segment to the outer diameter of a second segment is greater than or equal to 0.85, and the ratio of the outer diameter of a first segment to the outer diameter of a second segment is less than 1.

[0036] In this embodiment, the outer diameter of a first segment is smaller than the outer diameter of a second segment. If the ratio of the outer diameters of the first and second segments is too large, it indicates that the stiffness difference between the two segments is small, resulting in an insignificant effect on adjusting the stiffness of the first segment. Since the adapter shaft needs to transmit torque, if the ratio of the outer diameters of the first and second segments is too small, it may damage the overall structural strength of the adapter shaft, interfere with the transmission between the adapter shaft and other components, and increase the processing difficulty and cost of the first segment. This application, by adjusting the range of the ratio of the outer diameters of the first and second segments, helps to balance the stress distribution and transmission performance of the adapter shaft.

[0037] In one embodiment, a first segment and a second segment of the adapter shaft are distributed on the inner circumferential side of the motor shaft, and the first segment and the second segment are adjacent to each other along the axial direction of the adapter shaft. The distance between the inner circumferential surface of the first segment and the axis of the adapter shaft is less than the distance between the inner circumferential surface of the second segment and the axis of the adapter shaft along the radial direction of the adapter shaft.

[0038] In this embodiment, disregarding processing difficulty and cost, to increase the thickness difference between a first segment and a second segment, besides reducing the outer diameter of the first segment, the inner diameter of the first segment can also be increased. Increasing the radial distance between the inner circumferential surface of the first segment and the axis of the adapter shaft not only reduces the variation in stiffness from the first segment to the second segment but also increases the space of the adapter shaft cavity, thereby increasing the amount of oil that the adapter shaft can accommodate.

[0039] In one embodiment, the reducer includes a first planetary gear set, which is axially spaced from the motor shaft along the adapter shaft, and the planet carrier of the first planetary gear set is used to fixally connect to another first segment of the adapter shaft.

[0040] One of the first segments extends into the planet carrier of the first planetary set, and the other second segment of the transition shaft is adjacent to the other first segment. The outer peripheral surface of the other first segment is recessed relative to the outer peripheral surface of the other second segment along the radial direction of the transition shaft.

[0041] In this embodiment, the other first segment has a different positional arrangement in the powertrain than the first segment. Specifically, the other first segment extends into the inner circumference of the planet carrier of the first planetary gear set, which is used to fix the outer circumference of the other first segment. The other first segment and the other second segment are adjacent along the axial direction of the transition shaft. By increasing the difference in the outer diameters of the other first segment and the other second segment, the abrupt change in stiffness from the other first segment to the other second segment is reduced. Based on the relative position of the other first segment and the reducer, by reducing the outer diameter of the other first segment, the volume occupied by the other first segment is reduced, so that the inner diameter of the planet carrier of the first planetary gear set can also be reduced accordingly, thus reducing the layout difficulty of the planet carrier of the first planetary gear set in the reducer.

[0042] In one embodiment, another second segment of the adapter shaft is distributed along the axial direction of the adapter shaft between the planet carrier of the first planetary set and the motor shaft.

[0043] In this embodiment, the outer diameter of the other second segment is larger than that of the other first segment. By adjusting the position of the other second segment, contact between the other second segment and the planetary carrier of the first planetary gear set can be avoided, reducing interference to the transmission connection between the other first segment and the reducer. The through holes penetrating the other second segment are distributed between the planetary carrier of the first planetary gear set and the motor shaft, which helps to expand the coverage of the oil in the powertrain and improve the oil transmission efficiency.

[0044] In one embodiment, the reducer includes a second planetary gear set and a third planetary gear set, which are arranged sequentially along the axial direction of the adapter shaft. The second planetary gear set transmits power from the drive motor to the first planetary gear set, and transmits power through the first planetary gear set to the third planetary gear set. The third planetary gear set is used to drive another wheel of the electric vehicle via an output transmission element.

[0045] The powertrain includes a first locking member and a second locking member. When the first locking member is coupled with the second locking member, the first locking member and the second locking member are used to fix the adapter shaft and the output transmission component. The first locking member is used to fix the outer peripheral surface of another first segment, a portion of which extends from the planet carrier of the first planetary gear set into the first locking member.

[0046] In this embodiment, the drive motor outputs power to the second planetary gear set of the reducer. The second planetary gear set transmits power to the first planetary gear set, and also transmits power to the third planetary gear set via the first planetary gear set. The first and third planetary gear sets are each used to drive a wheel. The reducer integrates deceleration and differential functions, meaning it can both reduce the speed of the power output by the drive motor and enable differential rotation of the two wheels in scenarios such as vehicle turning.

[0047] In this embodiment, when one wheel slips, the differential function of the reducer needs to be temporarily disabled using the first and second locking components. The first and second locking components are respectively connected to the adapter shaft and the output transmission component. When the first and second locking components are coupled, the adapter shaft and the output transmission component can be fixedly connected through the first and second locking components, forcing both wheels to rotate at the same speed, thereby enabling the vehicle to get out of trouble.

[0048] In this embodiment, one first segment extends sequentially into the planet carrier of the first planetary gear set and the first locking member. The outer diameter of the other first segment is smaller, which reduces the volume occupied by the other first segment, allowing the inner diameter of the first locking member to be reduced accordingly, thus reducing the difficulty of arranging the first locking member in the reducer.

[0049] Secondly, embodiments of this application provide an electric vehicle, which includes a power battery and a powertrain as described in any embodiment of the first aspect, wherein the powertrain is used to receive power from the power battery and to drive the wheels of the electric vehicle.

[0050] In the embodiments of this application, the powertrain of any embodiment of the first aspect is applied to an electric vehicle. By reducing the risk of local stress concentration in the adapter shaft of the powertrain, the service life of the adapter shaft can be extended, which is beneficial to improving the safety performance of the powertrain and the electric vehicle. Attached Figure Description

[0051] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the embodiments of this application will be described below.

[0052] Figure 1 This is a schematic diagram of an electric vehicle provided in an embodiment of this application; Figure 2 This is a schematic diagram of the powertrain and wheels provided in an embodiment of this application; Figure 3 This is a schematic diagram of the powertrain provided in an embodiment of this application; Figure 4 This is a partial schematic diagram of the adapter shaft provided in an embodiment of this application; Figure 5 This is a cross-sectional view of the adapter shaft provided in an embodiment of this application; Figure 6 This is a cross-sectional view of the adapter shaft and motor shaft provided in the embodiments of this application; Figure 7 This is a partial schematic diagram of the adapter shaft provided in an embodiment of this application; Figure 8 This is a cross-sectional view of the adapter shaft provided in an embodiment of this application; Figure 9 This is a partial schematic diagram of the adapter shaft provided in an embodiment of this application; Figure 10 yes Figure 6 A partial enlarged view of part M in the adapter shaft and motor shaft shown; Figure 11 This is a partial schematic diagram of the adapter shaft provided in an embodiment of this application; Figure 12 This is a partial schematic diagram of the adapter shaft provided in an embodiment of this application; Figure 13 This is a schematic diagram of the powertrain provided in an embodiment of this application. Detailed Implementation

[0053] 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 some embodiments of this application, and not all embodiments.

[0054] For ease of understanding, the relevant technical terms involved in the embodiments of this application will be explained and described below.

[0055] Parallelism: The parallelism defined in the embodiments of this application is not limited to absolute parallelism. This definition of parallelism can be understood as basic parallelism, allowing for situations where the parallelism is not absolute due to factors such as assembly tolerance, design tolerance, and structural flatness.

[0056] Currently, the adapter shaft of a powertrain faces the problem of localized stress concentration. To alleviate the degree of stress concentration in the adapter shaft, embodiments of this application provide a powertrain. The powertrain includes a drive motor, a reducer, and an adapter shaft. The drive motor drives the adapter shaft through the reducer. The adapter shaft passes through the motor shaft of the drive motor, and the axial direction of the adapter shaft is parallel to the axial direction of the motor shaft. One end of the adapter shaft extending out of the motor shaft is used for power connection to one wheel of an electric vehicle.

[0057] The adapter shaft cavity is used to contain oil. The adapter shaft includes a through hole, a first section, and a second section. The first and second sections are arranged adjacent to each other along the axial direction of the adapter shaft. The through hole penetrates the second section, and its extension direction intersects the axial direction of the adapter shaft. The through hole connects the cavity of the second section and also connects the cavity of the first section. The distance between the outer and inner circumferential surfaces of the first section along the radial direction of the adapter shaft is less than the distance between the outer and inner circumferential surfaces of the second section. The second section is prone to stress concentration. In this embodiment, based on the adjacent arrangement of the first and second sections, the thickness of the first section is adjusted to reduce the variation in stiffness of the adapter shaft from the second section to the first section, which helps control the degree of stress concentration around the through hole.

[0058] The powertrain provided in this application embodiment can be applied to electric vehicles and helps to improve the overall performance of electric vehicles.

[0059] Please see Figure 1 , Figure 1 This is a schematic diagram of the electric vehicle 1 provided in an embodiment of this application.

[0060] The electric vehicle 1 in this embodiment includes a powertrain 10 and a power battery 20. In this embodiment, the electric vehicle 1 refers to a wheeled device driven or towed by a power unit. The power battery 20 supplies power to the powertrain 10; the power battery 20 can also be called a battery pack. The powertrain 10 is the power source for the electric vehicle 1 and drives the wheels 30 of the electric vehicle 1. In one embodiment, the electric vehicle 1 further includes a frame 40, which is used to mount the powertrain 10 and the power battery 20. The frame 40 is the structural skeleton of the electric vehicle 1 and can withstand the loads from the internal and external environments of the electric vehicle 1.

[0061] It should be noted that, Figure 1 The electric vehicle 1 is shown schematically only, including the powertrain 10, power battery 20, wheels 30 and frame 40, and does not represent the specific structure, size and positional relationship of the powertrain 10, power battery 20, wheels 30 and frame 40.

[0062] Please see Figure 2 and Figure 3 , Figure 2 This is a schematic diagram of the powertrain 10 and wheels 30 provided in an embodiment of this application. Figure 3 This is a schematic diagram of the powertrain 10 provided in the embodiments of this application.

[0063] The powertrain 10 of this application embodiment includes a drive motor 200 and a reducer 300. In one embodiment, the powertrain 10 further includes a motor controller 400. It should be noted that... Figure 2 This does not represent the actual structure, size, and positional relationship of the motor controller 400, drive motor 200, reducer 300, and wheel 30.

[0064] The power battery supplies power to the drive motor 200 via the motor controller 400. The motor controller 400 converts the direct current supplied by the power battery into alternating current and delivers the alternating current to the drive motor 200. In one embodiment, the motor controller 400 is also used to control at least one of the drive motor 200 or the reducer 300.

[0065] The drive motor 200 is used to convert electrical energy into mechanical energy to generate driving torque. In one embodiment, the drive motor 200 includes a motor shaft 210, a motor rotor, and a motor stator. The motor shaft 210 is used to fixably connect to the inner circumferential surface of the motor rotor. The windings of the motor stator are used to receive alternating current transmitted by the motor controller 400. After receiving the alternating current provided by the motor controller 400, the motor stator drives the motor rotor to rotate, thereby driving the motor shaft 210 to rotate.

[0066] The reducer 300 is used to reduce the speed of the power output by the drive motor 200 and increase the torque. Depending on the different architectures employed, the reducer 300 can be classified as a planetary reducer or a parallel shaft reducer. The planetary reducer uses an architecture where the input and output ends are arranged coaxially. In one embodiment, the planetary reducer includes at least one planetary gear set 310. Each planetary gear set 310 includes a sun gear 311, planet gears 312, a planet carrier 313, and a ring gear 314. The planet gears 312 mesh with at least one of the sun gears 311 and the ring gear 314. The planet carrier 313 is connected to the planet gears 312 via planetary shafts. One of the sun gears 311, planet carrier 313, and ring gear 314 is the input end, and at least one of them is the output end. The coaxial arrangement of the input and output ends of the planetary reducer is one of the differences between planetary reducers and parallel shaft reducers. In one embodiment, the sun gear 311 of a planetary gear set 310 is distributed on the outer peripheral surface of the motor shaft 210 of the drive motor 200. In one embodiment, the planet gears 312 are fixedly connected to the planet shafts, or the planet gears 312 and planet shafts are integrally formed. It should be noted that... Figure 3 This does not represent the actual structure, size, and positional relationship of the sun gear 311, planet gear 312, planet carrier 313, and gear ring 314 in planetary gear set 310.

[0067] In one embodiment, the powertrain 10 includes a differential, or the reducer 300 of the powertrain 10 has a differential function. When the electric vehicle is turning or traveling on uneven surfaces, the differential or the reducer 300 with a differential function enables the wheels 30 on different sides to rotate at different speeds.

[0068] In one embodiment, the powertrain 10 includes a transition shaft 100, a drive motor 200 for driving the transition shaft 100 via a reducer 300, and the transition shaft 100 for driving wheels via a drive shaft 500. In one embodiment, the transition shaft 100 and the drive shaft 500 are fixedly connected. Exemplarily, the transition shaft 100 and the drive shaft 500 are fixedly connected via a spline engagement. It should be noted that... Figure 2 This does not represent the actual structure, dimensions, or positional relationship between the adapter shaft 100 and the drive shaft 500.

[0069] Currently, the powertrain 10 typically utilizes an adapter shaft 100 to transmit oil, meeting the cooling and lubrication needs of different components within the powertrain 10. However, the through holes in the adapter shaft 100 used for receiving or outputting oil are prone to stress concentration, which is detrimental to extending the service life of the adapter shaft 100. This application's embodiment improves the structure of the powertrain 10, alleviating the degree of localized stress concentration in the adapter shaft 100, thereby enhancing the structural reliability of the adapter shaft 100 and improving the safety performance of the powertrain 10 and the electric vehicle.

[0070] The powertrain 10 provided in the embodiments of this application is described in detail below.

[0071] Please see Figures 4 to 6 , Figure 4 This is a partial schematic diagram of the adapter shaft 100 provided in an embodiment of this application. Figure 5 This is a cross-sectional view of the adapter shaft 100 provided in an embodiment of this application. Figure 6 This is a cross-sectional view of the adapter shaft 100 and the motor shaft 210 provided in the embodiments of this application.

[0072] The powertrain 10 includes a drive motor 200, a reducer 300, and an adapter shaft 100. The drive motor 200 drives the adapter shaft 100 via the reducer 300. The adapter shaft 100 passes through the motor shaft 210 of the drive motor 200, and one end of the adapter shaft 100 extends out of the motor shaft 210 for drive connection to one wheel of the electric vehicle. The axial direction O of the adapter shaft 100 is parallel to the axial direction of the motor shaft 210.

[0073] The adapter shaft 100 includes a through hole 110, a first segment 120, and a second segment 130. The first segment 120 and the second segment 130 are arranged adjacent to each other along the axial direction O of the adapter shaft 100. The through hole 110 penetrates the second segment 130, and the extension direction of the through hole 110 intersects the axial direction O of the adapter shaft 100. The through hole 110 is used to connect the shaft cavity of the first segment 120 through the shaft cavity of the second segment 130. The distance between the outer and inner circumferential surfaces of the first segment 120 along the radial direction R of the adapter shaft 100 is less than the distance between the outer and inner circumferential surfaces of the second segment 130. The radial distance between the outer and inner circumferential surfaces of the first segment 120 can also be understood as the radial thickness of the first segment 120. Since the first segment 120 has a shaft cavity, the radial thickness of the first segment 120 is less than half of its outer diameter.

[0074] The adapter shaft 100 and the reducer 300 have a transmission relationship. In one embodiment, the reducer 300 is a planetary reducer, which has the advantages of compact structure and small radial dimension compared to parallel shaft reducers. The input and output ends of the planetary reducer are arranged parallel to the axial direction O of the adapter shaft 100, which facilitates the adapter shaft 100 passing through the motor shaft 210.

[0075] Based on the distribution characteristics of the adapter shaft 100 in the powertrain 10, in addition to transmitting power, the adapter shaft 100 can also serve as a component of the cooling and lubrication system in the powertrain 10. By using the adapter shaft 100 to hold and transmit oil, it is easier for the oil to flow to the areas in the powertrain 10 that need to be cooled or lubricated, thereby improving the oil transmission efficiency.

[0076] To enable the adapter shaft 100 to guide and distribute oil, a through hole 110 needs to be formed in the adapter shaft 100. However, the through hole 110 reduces the structural strength of the adapter shaft 100. Machining the through hole 110 in the adapter shaft 100 requires the removal of some material, which disrupts the continuous cross-section of the adapter shaft 100, leading to localized stress concentration. Furthermore, the oil flow rate of the through hole 110 is related to its diameter. If the stress concentration is alleviated by reducing the diameter of the through hole 110, it will be difficult for the through hole 110 to meet the cooling and lubrication requirements of the powertrain 10.

[0077] To balance the structural strength of the adapter shaft 100 and the oil flow efficiency of the through hole 110, one possible solution is to increase the thickness of the adapter shaft 100. However, increasing the thickness of the adapter shaft 100 means increasing the radial dimension. To avoid interference, the structures arranged radially with the adapter shaft 100 also need to have their radial dimensions adjusted accordingly, leading to increased cost and weight of the powertrain 10. This is detrimental to achieving miniaturization and lightweight design of the powertrain 10 and also increases the difficulty of the powertrain 10's layout in the vehicle. In one embodiment, the structures arranged radially with the adapter shaft 100 include at least one of the motor shaft 210 of the drive motor 200, the motor rotor, and the planetary gear set 310 of the reducer 300.

[0078] This application embodiment comprehensively considers the structural strength, oil flow efficiency, and volume of the adapter shaft 100. By optimizing the variation of the stiffness of the adapter shaft 100 along the axial direction O of the adapter shaft 100, it is beneficial to alleviate the degree of local stress concentration of the adapter shaft 100 without reducing the diameter of the through hole 110 or increasing the overall radial dimension of the adapter shaft 100.

[0079] Specifically, the adapter shaft 100 includes a first segment 120 and a second segment 130 arranged adjacent to each other. Through holes 110 for transmitting oil are distributed in the second segment 130. The through holes 110 penetrate the second segment 130, facilitating the adapter shaft 100 to receive or output oil. The through holes 110 alter the continuity of the adapter shaft 100's cross-section, resulting in a decrease in the stiffness of the second segment 130. If the radial thickness of the first segment 120 is equal to the radial thickness of the second segment 130, the change in stiffness of the adapter shaft 100 from the first segment 120 to the second segment 130 will be significant, exacerbating the stress concentration at the through holes 110. Therefore, in this embodiment, the radial thickness of the first segment 120 is adjusted to be less than the radial thickness of the second segment 130. Since the first segment 120 and the second segment 130 are arranged adjacent to each other, reducing the radial thickness of the first segment 120 shortens the stiffness difference between the first segment 120 and the second segment 130, thereby reducing the abrupt change in stiffness of the adapter shaft 100 at the through hole 110 and alleviating the stress concentration around the through hole 110. Shortening the local thickness of the adapter shaft 100 helps reduce its weight and moment of inertia. In one embodiment, by reducing the radial thickness of the first segment 120, the stress concentration factor of the through hole 110 in the second segment 130 can be reduced by 0.4.

[0080] The embodiments of this application improve the structural reliability and service life of the adapter shaft 100 without interfering with the transmission of oil through the through hole 110, which helps to enhance the safety performance of the powertrain 10 and electric vehicles.

[0081] In one embodiment, the distribution of the first segment 120 in the adapter shaft 100 can be determined based on its relative position to the second segment 130 and a comparison with the radial thickness of the second segment 130.

[0082] like Figure 5 and Figure 6 As shown, in one embodiment, the extension direction of the through hole 110 is parallel to the radial direction R of the adapter shaft 100, which helps to reduce the machining difficulty of the through hole 110 and shorten the flow path of the oil in the through hole 110.

[0083] It is understood that the extending direction of the through hole 110 intersects the axial direction O of the adapter shaft 100, and is not limited to the case where the extending direction of the through hole 110 is parallel to the radial direction R of the adapter shaft 100. Please refer to [link / reference]. Figure 7 and Figure 8 , Figure 7 This is a partial schematic diagram of the adapter shaft 100 provided in an embodiment of this application. Figure 8This is a cross-sectional view of the adapter shaft 100 provided in an embodiment of this application. In another embodiment, the extending direction of the through hole 110 intersects the radial direction R of the adapter shaft 100. By adjusting the extending direction of the through hole 110, the opening of the through hole 110 can avoid obstruction from other structures in the adapter shaft 100, reducing the risk of oil blockage.

[0084] like Figure 4 As shown, the adapter shaft 100 may include multiple first segments 120 and multiple second segments 130. The following section will first explain how to improve the structural strength of the adapter shaft 100 based on any two adjacent first segments 120 and second segments 130.

[0085] Please continue reading. Figures 4 to 6 In one embodiment, the length of the first segment 120 along the axial direction O of the adapter shaft 100 is greater than the length of the second segment 130.

[0086] In this embodiment, the axial length of the first segment 120 is related to the stiffness distribution of the adapter shaft 100. By adjusting the relationship between the axial lengths of the first segment 120 and the second segment 130, the effect of the first segment 120 in adjusting the stiffness variation of the adapter shaft 100 can be improved, avoiding the exacerbation of stress concentration due to abrupt changes in stiffness. Since the radial thickness of the second segment 130 is greater than that of the first segment 120, controlling the axial length of the second segment 130 helps to reduce the cost and weight of the adapter shaft 100.

[0087] Please continue reading. Figures 4 to 6 In one embodiment, the length of the second segment 130 along the axial direction O of the adapter shaft 100 is greater than the length of the through hole 110. The axial length of the through hole 110 can also be understood as the diameter of the through hole 110.

[0088] In this embodiment, the through hole 110 extends radially R through the second segment 130 along the adapter shaft 100, and the second segment 130 provides a stress dispersion path for the through hole 110. By adjusting the axial length relationship between the second segment 130 and the through hole 110, the stress dispersion effect of the second segment 130 can be enhanced, the stress concentration degree of the through hole 110 can be reduced, thereby improving the structural strength of the adapter shaft 100.

[0089] In this embodiment, the axial length of the second segment 130 is greater than the axial length of the through hole 110 and less than the axial length of the first segment 120, which can balance the effect of stress dispersion with the cost and weight of the adapter shaft 100.

[0090] Please continue reading. Figures 4 to 6 In one embodiment, the distance between the first segment 120 along the axial direction O of the adapter shaft 100 and the through hole 110 is less than the length of the through hole 110.

[0091] In this embodiment, since the radial thickness of the second segment 130 is relatively large, if the axial distance between the first segment 120 and the through hole 110 is too large, it is easy to exacerbate the abrupt change in the stiffness of the second segment 130. This embodiment reduces the axial distance between the first segment 120 and the through hole 110 and adjusts the layout of the through hole 110 in the second segment 130, which helps to reduce the difficulty of adjusting the stiffness change of the first segment 120.

[0092] In one embodiment, the ratio of the outer diameter of the second segment 130 along the radial direction R of the adapter shaft 100 to the diameter of the through hole 110 along the axial direction O of the adapter shaft 100 is greater than or equal to 5 and less than or equal to 15. In this embodiment, the diameter of the through hole 110 affects the degree of stress concentration and the oil flow rate. By adjusting the ratio of the outer diameter of the second segment 130 to the diameter of the through hole 110, this embodiment facilitates the dispersion of some of the stress around the through hole 110 by the second segment 130, which helps ensure that the diameter of the through hole 110 meets the oil flow rate requirements.

[0093] like Figure 4 As shown, the second segment 130 includes an annular protrusion 131 that protrudes from the outer peripheral surface of the second segment 130. The annular protrusion 131 surrounds the outer peripheral surface of the adapter shaft 100. Please refer to... Figure 9 , Figure 9 This is a partial schematic diagram of the adapter shaft 100 provided in an embodiment of this application. In another embodiment, the second segment 130 may also include columnar protrusions 132, which protrude from the outer peripheral surface of the second segment 130. Through holes 110 penetrate the columnar protrusions 132, and the number of columnar protrusions 132 is equal to the number of through holes. The annular protrusions 131 and columnar protrusions 132 can increase the thickness difference between the first segment 120 and the second segment 130. The annular protrusions 131 are circumferentially continuous symmetrical structures, which helps to evenly distribute stress. The columnar protrusions 132 can reduce the material used in machining the adapter shaft 100, which is beneficial to reducing the weight of the adapter shaft. It should be noted that the annular protrusion 131 and the columnar protrusion 132 are formed after the first section 120 of the adapter shaft 100 is machined. They are not directly machined into the second section 130 of the adapter shaft 100. The embodiment of this application alleviates the stress concentration of the through hole by reducing the stiffness of the first section 120, rather than by increasing the radial thickness of the second section 130.

[0094] Please see Figure 10 , Figure 10 yes Figure 6The diagram shows a partial enlarged view of portion M in the adapter shaft 100 and motor shaft 210. In one embodiment, the second segment 130 includes a first portion 133 and a second portion 134, with a through hole 110 penetrating the first portion 133. The second portion 134 is located between the first portion 133 and the first segment 120 along the axial direction O of the adapter shaft 100. The distance between the outer and inner circumferential surfaces of the second portion 134 decreases along the axial direction O of the adapter shaft 100 from the first portion 133 toward the first segment 120.

[0095] In this embodiment, the radial thickness of the second segment 130 is greater than that of the first segment 120. By using the first portion 133 and the second portion 134 to adjust the radial thickness of the second segment 130, abrupt changes in the radial thickness of the second segment 130 relative to the first segment 120 can be avoided. The second portion 134 can act as a transitional element to adjust stiffness changes, reducing the risk of stress concentration at the connection between the first segment 120 and the second segment 130. In one embodiment, the surface of the second portion 134 facing the first segment 120 along the axial direction O of the adapter shaft 100 is an arc surface.

[0096] To enable the adapter shaft 100 to deliver oil to different components of the powertrain 10, the adapter shaft 100 typically includes multiple through holes 110. To address the stress concentration issue of the multiple through holes 110, the number of the first section 120 and the second section 130 needs to be increased accordingly.

[0097] Please continue reading. Figures 4 to 6 In one embodiment, the adapter shaft 100 includes a plurality of first segments 120 and a plurality of second segments 130, with each second segment 130 distributed between two first segments 120 along the axial direction O of the adapter shaft 100. For example, as shown... Figure 6 As shown, the second segment 130a is distributed between the first segment 120a and the first segment 120c.

[0098] In this embodiment, two second segments 130 are distributed on both sides of each first segment 120 along the axial direction O of the adapter shaft 100. By adjusting the arrangement of the first segments 120 and the second segments 130, the stiffness variation on different sides of the through hole 110 can be adjusted using the two first segments 120, thereby reducing the degree of stress concentration around the through hole 110.

[0099] In this embodiment, each first segment 120 is distributed between two second segments 130, indicating that the second segment 130 is not located at the end of the adapter shaft 100. This facilitates the avoidance of the through hole 110 from the high-stress area of ​​the adapter shaft 100 used for power transmission, thus preventing the stress caused by the through hole 110 from interfering with the transmission of the adapter shaft 100.

[0100] In one embodiment, the surfaces of the second segment 130 facing the two first segments 120 are both curved surfaces.

[0101] Please continue reading. Figures 4 to 6 In one embodiment, at least one first segment 120 is distributed between two second segments 130. For example, as shown... Figure 6 As shown, the first segment 120c is distributed between the second segment 130a and the second segment 130c. In this embodiment, at least one first segment 120 can reduce the occurrence of abrupt changes in stiffness in adjacent areas of the two second segments 130, which is beneficial to improving the stiffness distribution of the adapter shaft 100 and alleviating the stress concentration in the through hole 110.

[0102] Please continue reading. Figures 4 to 6 In one embodiment, the adapter shaft 100 includes a plurality of through holes 110, with one through hole 110 and another through hole 110 spaced apart along the axial direction O of the adapter shaft 100. Along the axial direction O of the adapter shaft 100, the length of one through hole 110 is less than the length of the other through hole 110, and the outer diameter of the second segment 130 penetrated by one through hole 110 is less than or equal to the outer diameter of the second segment 130 penetrated by the other through hole 110.

[0103] In this embodiment, the diameter of the through hole 110 is related to the oil flow rate, and the powertrain 10 has different oil flow rate requirements for different through holes 110. When the diameter of the through hole 110 is large, the radial thickness of the second section 130 can be appropriately increased to compensate for some of the impact of the through hole 110 on the structural strength of the first section 120. When the diameter of the through hole 110 is small, the radial thickness of the second section 130 can be appropriately reduced to reduce the cost of the adapter shaft 100.

[0104] Multiple first segments 120 and multiple second segments 130 are arranged along the axial direction O of the adapter shaft 100. Based on the relative positions of the first segments 120 and second segments 130 with the drive motor 200 and the reducer 300, the structure or layout of the drive motor 200 and the reducer 300 can be optimized by utilizing the structural characteristics of the first segments 120 and second segments 130.

[0105] Please continue reading. Figure 6 In one embodiment, the first segment 120a and the second segment 130a of the adapter shaft 100 are distributed on the inner circumferential side of the motor shaft 210, and the first segment 120a and the second segment 130a are adjacent along the axial direction O of the adapter shaft 100. The distance between the outer circumferential surface of the first segment 120a and the inner circumferential surface of the motor shaft 210 along the radial direction R of the adapter shaft 100 is greater than the distance between the outer circumferential surface of the second segment 130a and the inner circumferential surface of the motor shaft 210.

[0106] In this embodiment, the second segment 130a is distributed on the inner circumferential side of the motor shaft 210, and the through hole 110 of the second segment 130a can transmit oil to the gap between the adapter shaft 100 and the motor shaft 210. Exemplarily, after the oil flows into the gap between the adapter shaft 100 and the motor shaft 210, it can flow through the motor shaft 210 into the rotor oil passage of the motor rotor, thereby achieving cooling and heat dissipation for the motor rotor. The first segment 120a and the second segment 130a are arranged adjacent to each other, and the outer circumferential surface of the first segment 120a can participate in forming part of the gap between the adapter shaft 100 and the motor shaft 210. To ensure that the radial thickness of the first segment 120a is less than the radial thickness of the second segment 130a, and to reduce the flow resistance of the oil, this embodiment adjusts the outer diameter of the first segment 120a to be smaller than the outer diameter of the second segment 130a. By reducing the outer diameter of the first section 120a, not only can the stiffness change from the first section 120a to the second section 130a be reduced, alleviating the stress concentration in the second section 130a, but the space between the first section 120a and the inner circumferential surface of the motor shaft 210 can also be increased, which is beneficial to improving the transmission efficiency of the oil.

[0107] In this embodiment, from the perspective of the powertrain 10 layout, by adjusting the outer diameter of the first segment 120a and reducing the radial space occupied by the first segment 120a, it is possible to avoid adapting the adapter shaft 100 by increasing the inner diameter of the motor shaft 210 and the motor rotor. This helps to miniaturize the powertrain 10 and reduces the layout difficulty of the powertrain 10 in the vehicle.

[0108] Please refer to the following: Figure 6 and Figure 10 In one embodiment, the through hole 110 is used to transfer oil to the gap between the adapter shaft 100 and the motor shaft 210, with the other end of the adapter shaft 100 extending from one end face of the motor shaft 210. The inner circumferential surface of the motor shaft 210 includes an oil-blocking protrusion 211, which protrudes towards the first segment 120a. The oil-blocking protrusion 211 is distributed between the second segment 130a and one end face of the motor shaft 210.

[0109] In this embodiment, the other end of the adapter shaft 100 extends from the motor shaft 210. The oil flowing between the adapter shaft 100 and the motor shaft 210 tends to flow towards the end of the motor shaft 210 under centrifugal force, easily leading to oil leakage. To improve oil utilization, this embodiment utilizes an oil-blocking protrusion 211 to form a stepped structure between the adapter shaft 100 and the motor shaft 210, controlling oil flow and preventing excessive oil accumulation at the end of the motor shaft 210. The relatively small outer diameter of the first section 120a provides space for the oil-blocking protrusion 211 on the inner circumferential surface of the motor shaft 210. The oil-blocking protrusion 211 is distributed between the second section 130a and one end face of the motor shaft 210, reducing the risk of oil leakage while ensuring the oil-blocking protrusion 211 avoids obstruction from the through hole 110. This facilitates stable oil flow within the shaft cavity of the adapter shaft 100 and the gap between the adapter shaft 100 and the motor shaft 210.

[0110] In one embodiment, the oil-blocking protrusion 211 is an annular oil-blocking protrusion, which surrounds the inner circumferential surface of the motor shaft 210 along the circumferential direction of the adapter shaft 100. This embodiment of the application is beneficial in enhancing the oil-blocking effect of the oil-blocking protrusion 211 and reducing the possibility of oil leakage.

[0111] In one embodiment, the ratio of the outer diameter of the first segment 120a to the outer diameter of the second segment 130a is greater than or equal to 0.85. The ratio of the outer diameter of the first segment 120a to the outer diameter of the second segment 130a is less than 1.

[0112] In this embodiment, the outer diameter of the first segment 120a is smaller than the outer diameter of the second segment 130a. If the ratio of the outer diameters of the first segment 120a and the second segment 130a is too large, it indicates that the stiffness difference between the two segments is small, resulting in an insignificant effect on adjusting the stiffness of the first segment 120a. Since the adapter shaft 100 needs to transmit torque, if the ratio of the outer diameters of the first segment 120a and the second segment 130a is too small, it may damage the overall structural strength of the adapter shaft 100, interfere with the transmission between the adapter shaft 100 and other components, and increase the processing difficulty and cost of the first segment 120a. This application, by adjusting the range of the ratio of the outer diameters of the first segment 120a and the second segment 130a, helps to balance the stress distribution and transmission performance of the adapter shaft 100. In one embodiment, the ratio of the outer diameter of the first segment 120a to the outer diameter of the second segment 130a can be any one of 0.85, 0.86, 0.87, 0.88, 0.89, 0.90, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, and 0.99. In another embodiment, the ratio of the outer diameter of the first segment 120a to the outer diameter of the second segment 130a can be 0.95.

[0113] like Figure 6As shown, in one embodiment, the adapter shaft 100 further includes a second segment 130b and a second segment 130c, at least one of the second segment 130b and the second segment 130c satisfying the above-mentioned ratio range with the adjacent first segment 120.

[0114] Please see Figure 11 , Figure 11 This is a partial schematic diagram of the adapter shaft 100 provided in an embodiment of this application.

[0115] In one embodiment, the distance between the inner circumferential surface of the first segment 120a along the radial direction R of the adapter shaft 100 and the axis O1 of the adapter shaft 100 is less than the distance between the inner circumferential surface of the second segment 130a and the axis O1 of the adapter shaft 100.

[0116] In this embodiment, if processing difficulty and cost are not considered, in order to increase the thickness difference between the first segment 120a and the second segment 130a, in addition to reducing the outer diameter of the first segment 120a, the inner diameter of the first segment 120a can also be increased. Increasing the radial distance between the inner circumferential surface of the first segment 120a and the axis O1 of the adapter shaft 100 can not only reduce the variation in stiffness from the first segment 120a to the second segment 130a, but also increase the space of the shaft cavity of the first segment 120a, thereby increasing the amount of oil that the adapter shaft 100 can accommodate.

[0117] In one embodiment, the first segment 120 of the adapter shaft 100 is obtained by further processing after the adapter shaft 100 is formed. When the adapter shaft 100 includes multiple first segments 120, since the inner diameters of the first segment 120 and the second segment 130 are not equal, it is difficult and costly to process multiple first segments 120 on the inner circumferential surface of the adapter shaft 100 without affecting the inner diameter of the second segment 130. Therefore, in order to reduce the impact of processing the first segment 120 on the second segment 130, the first segment 120 with a larger inner diameter can be placed at the end of the adapter shaft 100, reducing the difficulty of processing the inner circumferential surface of the adapter shaft 100.

[0118] In one embodiment, the through hole 110 penetrates both the outer and inner circumferential surfaces of the second segment 130a. Under torsion, the outer circumferential surface of the second segment 130a deforms more than the inner circumferential surface, causing the outer circumferential surface of the second segment 130a to bear greater stress. Therefore, increasing the radial distance between the outer circumferential surface of the first segment 120a and the inner circumferential surface of the motor shaft 210 better alleviates the stress concentration around the through hole of the second segment 130a.

[0119] Please see Figure 12 , Figure 12 This is a partial schematic diagram of the adapter shaft 100 provided in an embodiment of this application.

[0120] In one embodiment, the distance between the outer peripheral surface of the first segment 120a along the radial direction R of the adapter shaft 100 and the inner peripheral surface of the motor shaft 210 is greater than the distance between the outer peripheral surface of the second segment 130a and the inner peripheral surface of the motor shaft 210. The distance between the inner peripheral surface of the first segment 120a along the radial direction R of the adapter shaft 100 and the axis O1 of the adapter shaft 100 is less than the distance between the inner peripheral surface of the second segment 130a and the axis O1 of the adapter shaft 100.

[0121] In this embodiment, machining the outer and inner circumferential surfaces of the first segment 120a helps to disperse the stress on the outer and inner circumferential surfaces of the second segment 130a. In one embodiment, Figure 5 , Figure 11 , Figure 12 The structure of the first segment 120a shown can also be applied to the first segments 120b and 120c.

[0122] Understandably, in practical applications, appropriate processing methods can be selected according to different needs, so that the first segment 120 of the adapter shaft 100 presents as follows: Figure 5 , Figure 11 , Figure 12 The structure of the first segment 120a shown.

[0123] Please refer to the following: Figure 6 and Figure 13 , Figure 13 This is a schematic diagram of the powertrain 10 provided in the embodiments of this application.

[0124] In one embodiment, the reducer 300 includes a first planetary gear set 310a, which is spaced from the motor shaft 210 along the axial direction O of the adapter shaft 100. The planet carrier 313a of the first planetary gear set 310a is used to fixably connect to the first section 120b of the adapter shaft 100. The first section 120b extends into the planet carrier 313a of the first planetary gear set 310a, and a second section 130b of the adapter shaft 100 is adjacent to the first section 120b. The outer peripheral surface of the first section 120b is recessed relative to the outer peripheral surface of the second section 130b along the radial direction R of the adapter shaft 100.

[0125] In this embodiment, the first segment 120b is positioned differently from the first segment 120a in the powertrain 10. In one embodiment, the first segment 120b is located at the other end of the adapter shaft 100 extending from the motor shaft 210. The first segment 120b is used to fixably connect the first planetary gear set 310a of the reducer 300. Specifically, the first segment 120b extends into the inner circumferential side of the planet carrier 313a of the first planetary gear set 310a, and the planet carrier 313a of the first planetary gear set 310a is used to fixably connect the outer circumferential surface of the first segment 120b. The first segment 120b and the second segment 130b are adjacent along the axial direction O of the adapter shaft 100. By increasing the difference in the outer diameter of the first segment 120b and the second segment 130b, the abrupt change in stiffness from the first segment 120b to the second segment 130b is reduced. Based on the relative position of the first segment 120b and the reducer 300, by reducing the outer diameter of the first segment 120b, the volume occupied by the first segment 120b is reduced, so that the inner diameter of the planet carrier 313a of the first planetary gear 310a can also be reduced accordingly, thereby reducing the layout difficulty of the planet carrier 313a of the first planetary gear 310a in the reducer 300.

[0126] Please continue reading. Figure 13 In one embodiment, along the axial direction of the adapter shaft 100, the second segment 130b of the adapter shaft 100 is distributed between the planet carrier 313a of the first planetary set 310a and the motor shaft 210.

[0127] In this embodiment, the outer diameter of the second segment 130b is larger than that of the first segment 120b. By adjusting the position of the second segment 130b, contact between the second segment 130b and the planet carrier 313a of the first planetary gear set 310a can be avoided, reducing interference to the transmission connection between the first segment 120b and the reducer 300. The through-hole 110 penetrating the second segment 130b is distributed between the planet carrier 313a of the first planetary gear set 310a and the motor shaft 210, which helps to expand the coverage area of ​​the oil in the powertrain 10 and improve the oil transmission efficiency.

[0128] Please continue reading. Figure 13 In one embodiment, the reducer 300 includes a second planetary gear set 310b and a third planetary gear set 310c, which are arranged sequentially along the axial direction O of the adapter shaft 100. The second planetary gear set 310b is used to transmit power from the drive motor 200 to the first planetary gear set 310a, and the second planetary gear set 310b is used to transmit power from the first planetary gear set 310a to the third planetary gear set 310c. The third planetary gear set 310c is used to drive another wheel of the electric vehicle via an output transmission member 320.

[0129] The powertrain 10 includes a first locking member 600 and a second locking member 700. When the first locking member 600 is coupled with the second locking member 700, the first locking member 600 is used to fix the adapter shaft 100 and the output transmission member 320. The first locking member 600 is used to fix the outer peripheral surface of the first segment 120b, and a portion of the first segment 120b extends from the planet carrier 313a of the first planetary gear 310a into the first locking member 600.

[0130] In this embodiment, the drive motor 200 outputs power to the second planetary gear set 310b of the reducer 300. In one embodiment, the outer peripheral surface of the motor shaft 210 includes a sun gear 311, and the planet gears 312 of the second planetary gear set 310b mesh with the sun gear 311. The second planetary gear set 310b transmits power to the first planetary gear set 310a, and also transmits power to the third planetary gear set 310c via the first planetary gear set 310a. The first planetary gear set 310a and the third planetary gear set 310c are respectively used to drive a wheel. The reducer 300 integrates reduction and differential functions, meaning that the reducer 300 can both reduce the speed of the power output by the drive motor 200 and enable differential rotation of the two wheels in scenarios such as vehicle turning.

[0131] In this embodiment, when one wheel slips, the differential function of the reducer 300 needs to be temporarily disabled using the first locking member 600 and the second locking member 700. The first locking member 600 and the second locking member 700 are respectively connected to the adapter shaft 100 and the output transmission member 320. When the first locking member 600 and the second locking member 700 are coupled, the adapter shaft 100 and the output transmission member 320 can be fixedly connected through the first locking member 600 and the second locking member 700, forcing both wheels to rotate at the same speed, thereby enabling the vehicle to get out of trouble. In one embodiment, the output transmission member 320 can be an output disc.

[0132] In this embodiment, the first segment 120b extends sequentially into the planet carrier 313a of the first planetary gear set 310a and the first locking member 600. The outer diameter of the first segment 120b is small, which can reduce the volume occupied by the first segment 120b, so that the inner diameter of the first locking member 600 can also be reduced accordingly, reducing the layout difficulty of the first locking member 600 in the reducer 300.

[0133] The powertrain and electric vehicle provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and embodiments of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in specific embodiments and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A powertrain, characterized in that, The powertrain includes a drive motor, a reducer, and an adapter shaft. The drive motor drives the adapter shaft via the reducer. The adapter shaft passes through the motor shaft of the drive motor, and one end of the adapter shaft extending out of the motor shaft is used for drive connection to one wheel of the electric vehicle. The adapter shaft includes a through hole, a first section, and a second section. The first section and the second section are arranged adjacent to each other along the axial direction of the adapter shaft. The through hole passes through the second section, and the extension direction of the through hole intersects the axial direction of the adapter shaft. The through hole is used to connect the shaft cavity of the first section through the shaft cavity of the second section. The distance between the outer circumferential surface and the inner circumferential surface of the first section along the radial direction of the adapter shaft is less than the distance between the outer circumferential surface and the inner circumferential surface of the second section.

2. The powertrain according to claim 1, characterized in that, The length of the first segment along the axial direction of the adapter shaft is greater than the length of the second segment.

3. The powertrain according to claim 1 or 2, characterized in that, The length of the second segment along the axial direction of the adapter shaft is greater than the length of the through hole.

4. The powertrain according to any one of claims 1-3, characterized in that, The distance between the first segment along the axial direction of the adapter shaft and the through hole is less than the length of the through hole.

5. The powertrain according to any one of claims 1-4, characterized in that, The second segment includes a first part and a second part, the through hole penetrates the first part, the second part is located between the first part and the first segment along the axial direction of the adapter shaft, and the distance between the outer circumferential surface and the inner circumferential surface of the second part decreases from the first part toward the first segment along the axial direction of the adapter shaft.

6. The powertrain according to any one of claims 1-5, characterized in that, The adapter shaft includes a plurality of first segments and a plurality of second segments, with each second segment distributed between two first segments along the axial direction of the adapter shaft.

7. The powertrain according to any one of claims 1-6, characterized in that, The adapter shaft includes a plurality of through holes, one through hole and another through hole are spaced apart along the axial direction of the adapter shaft, the length of the one through hole along the axial direction of the adapter shaft is less than the length of the other through hole, and the outer diameter of the second segment through which the one through hole penetrates is less than or equal to the outer diameter of the second segment through which the other through hole penetrates.

8. The powertrain according to any one of claims 1-7, characterized in that, The first segment and the second segment of the adapter shaft are distributed on the inner circumferential side of the motor shaft. The first segment and the second segment are adjacent to each other along the axial direction of the adapter shaft. The distance between the outer circumferential surface of the first segment and the inner circumferential surface of the motor shaft is greater than the distance between the outer circumferential surface of the second segment and the inner circumferential surface of the motor shaft along the radial direction of the adapter shaft.

9. The powertrain according to claim 8, characterized in that, The through hole is used to transmit oil to the gap between the adapter shaft and the motor shaft, and the other end of the adapter shaft extends from one end face of the motor shaft, wherein: The inner circumferential surface of the motor shaft includes an oil-blocking protrusion that protrudes toward the first segment and is distributed between the second segment and one end face of the motor shaft.

10. The powertrain according to claim 8 or 9, characterized in that, The ratio of the outer diameter of the first segment to the outer diameter of the second segment is greater than or equal to 0.85, and the ratio of the outer diameter of the first segment to the outer diameter of the second segment is less than 1.

11. The powertrain according to any one of claims 1-10, characterized in that, The first segment and the second segment of the adapter shaft are distributed on the inner circumferential side of the motor shaft. The first segment and the second segment are adjacent to each other along the axial direction of the adapter shaft. The distance between the inner circumferential surface of the first segment and the axis of the adapter shaft is less than the distance between the inner circumferential surface of the second segment and the axis of the adapter shaft along the radial direction of the adapter shaft.

12. The powertrain according to any one of claims 1-11, characterized in that, The reducer includes a first planetary gear set, which is axially spaced from the motor shaft along the adapter shaft. The planet carrier of the first planetary gear set is used to fixably connect to another first segment of the adapter shaft, wherein: The other first segment extends into the planet carrier of the first planetary set, and the other second segment of the adapter shaft is adjacent to the other first segment, with the outer peripheral surface of the other first segment recessed relative to the outer peripheral surface of the other second segment along the radial direction of the adapter shaft.

13. The powertrain according to claim 12, characterized in that, Along the axial direction of the adapter shaft, another second segment of the adapter shaft is distributed between the planet carrier of the first planetary set and the motor shaft.

14. The powertrain according to claim 12 or 13, characterized in that, The reducer includes a second planetary gear set and a third planetary gear set, which are arranged sequentially along the axial direction of the adapter shaft. The second planetary gear set transmits power from the drive motor to the first planetary gear set, and transmits power from the first planetary gear set to the third planetary gear set. The third planetary gear set is used to drive another wheel of the electric vehicle via an output transmission component. The powertrain includes a first locking member and a second locking member. When the first locking member is coupled with the second locking member, the first locking member and the second locking member are used to fix the adapter shaft and the output transmission member. The first locking member is used to fix the outer peripheral surface of the other first segment. A portion of the other first segment extends from the planet carrier of the first planetary gear set into the first locking member.

15. An electric vehicle, characterized in that, The electric vehicle includes a power battery and a powertrain as described in any one of claims 1-14, the powertrain being used to receive power from the power battery and to drive the wheels of the electric vehicle.

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