Power assembly and electric vehicle

Abstract

The application provides a power assembly and an electric vehicle. The housing of the power assembly comprises a motor cavity and a reducer cavity. A rotating shaft of a driving motor extends into the reducer cavity from the motor cavity along the axial direction of the driving motor through an intermediate bearing seat. The rotating shaft comprises a first section, a second section and a third section. The first section is used for fixing a motor rotor, the second section is used for fixing an inner ring of an intermediate bearing, and the third section has a tooth portion. The first section is distributed in the motor cavity, and the third section is distributed in the reducer cavity. An inner circumferential wall of the intermediate bearing seat is used for fixing the intermediate bearing, and a bottom of the intermediate bearing seat along the axial direction of the driving motor is used for abutting against the intermediate bearing. An opening of the intermediate bearing seat along the axial direction of the driving motor faces away from the reducer cavity. The application integrates the function of an input shaft of the reducer into the rotating shaft of the driving motor, and can avoid the problems of high disassembly and assembly difficulty, noise generation and easy failure caused by the spline fit between the rotating shaft and the input shaft.

Description

Technical Field

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

[0002] In the electric vehicle industry, the powertrain is the source of power for the entire vehicle. With the development of electric vehicles, the requirements for NVH performance and miniaturization design of the powertrain are increasing. In the powertrain, the motor transmits torque through the input shaft of the motor-axial reducer to drive the wheels. Currently, the motor shaft and input shaft are typically connected using a spline joint. However, spline joints are difficult to install and remove, and can lead to low-level noise and wear failure, which is detrimental to improving the efficiency of the powertrain and the safety performance of electric vehicles. Utility Model Content

[0003] This application provides a powertrain and an electric vehicle.

[0004] In a first aspect, embodiments of this application provide a powertrain. The powertrain housing includes a motor cavity and a reducer cavity. The motor cavity accommodates the motor rotor of the drive motor in the powertrain, and the reducer cavity accommodates the parallel shaft gear set of the reducer in the powertrain. Along the axial direction of the drive motor, the drive motor shaft extends from the motor cavity through an intermediate bearing housing into the reducer cavity.

[0005] The shaft comprises a first section, a second section, and a third section arranged sequentially along the axial direction of the drive motor. The first section is used to fix the motor rotor, the second section is used to fix the inner ring of the intermediate bearing, and the third section has teeth for meshing with the intermediate driven gear of the parallel shaft gear set. The first section is located in the motor cavity, and the third section is located in the reducer cavity.

[0006] The inner circumferential wall of the intermediate bearing housing is used to fix the outer ring of the intermediate bearing, and the bottom of the intermediate bearing housing along the axial direction of the drive motor is used to abut against the outer ring of the intermediate bearing. The opening of the intermediate bearing housing along the axial direction of the drive motor faces away from the reducer cavity.

[0007] In this embodiment of the application, in order to avoid the problems of cumbersome disassembly and assembly, noise and fretting wear caused by the splined connection of the existing motor shaft and input shaft, this embodiment of the application is based on the drive motor shaft and integrates the function of the input shaft into the shaft, that is, using the shaft to replace the existing combination of motor shaft and input shaft.

[0008] Specifically, the shaft extends from the motor cavity into the reducer cavity. The first section of the shaft is located inside the motor cavity, and the third section is located inside the reducer cavity, providing the prerequisite for the shaft to integrate the function of an input shaft. The first section is used to fix the motor rotor, and the shaft itself can directly receive the torque transmitted by the motor rotor, thus functioning as a motor shaft. The third section has teeth that mesh with the intermediate driven gear, essentially acting as an input gear connected to the reducer. The shaft can directly transmit torque to the reducer. Because the shaft avoids the spline fit structure, this embodiment reduces the difficulty of disassembly and assembly, reduces the noise generated by the shaft, improves NVH performance, reduces the risk of failure of the shaft-reducer transmission connection, and extends the service life of the shaft.

[0009] In this embodiment, in addition to the first and third segments, the shaft also includes a second segment. The second segment is used to fix the inner ring of the intermediate bearing, and the intermediate bearing housing is used to fix the outer ring of the intermediate bearing. The intermediate bearing serves to support the shaft. The shaft integrates the first segment, the second segment, and the gear section, which can be machined as a single piece to easily meet coaxiality requirements. Since the shaft does not require space to be reserved for spline fit, it has a high degree of integration, which can shorten the axial dimension of the shaft and help to achieve miniaturized powertrain design.

[0010] In this embodiment, the shaft extends from the motor cavity into the reducer cavity through the intermediate bearing housing. During the installation and disassembly of the shaft, the orientation of the opening of the intermediate bearing housing will affect the difficulty and cost of disassembly and assembly.

[0011] Specifically, if the opening of the intermediate bearing housing faces the reducer cavity: during installation, the shaft passes through the bottom and opening of the intermediate bearing housing sequentially, making it impossible to fix the intermediate bearing to the shaft beforehand. Otherwise, it would be blocked by the bottom of the intermediate bearing housing, forcing the intermediate bearing to be fixed there first. In this case, the shaft needs to pass through the inner ring of the intermediate bearing during installation, which can easily lead to impacts. The shaft is usually installed synchronously with the motor rotor after being fixed. During installation, the position of the intermediate bearing is obstructed by the shaft and motor rotor, increasing the difficulty of ensuring coaxiality. Furthermore, during shaft disassembly, due to the obstruction at the bottom of the intermediate bearing housing, the intermediate bearing cannot be removed synchronously with the shaft; it must be separated from the shaft first, which can easily damage the intermediate bearing.

[0012] To reduce the difficulty and cost of powertrain assembly and disassembly, in this embodiment of the application, when the shaft integrates the first, second, and third sections, the opening of the intermediate bearing housing is adjusted to face away from the reducer cavity along the axial direction of the drive motor. During shaft installation, the intermediate bearing can be pre-fixed to the second section of the shaft, allowing the intermediate bearing and shaft to be installed synchronously. Compared to the installation method where the shaft passes through the inner ring of the intermediate bearing during installation, in this embodiment, the shaft and intermediate bearing pass through the opening of the intermediate bearing housing simultaneously until the outer ring of the intermediate bearing abuts against the bottom of the intermediate bearing housing. This simplifies the assembly process and avoids collisions between the intermediate bearing and the shaft. Furthermore, during shaft disassembly, since the intermediate bearing is not obstructed by the bottom of the intermediate bearing housing, it can be detached from the shaft as a single unit, reducing damage to the intermediate bearing and extending the service life of both the shaft and the intermediate bearing.

[0013] In one embodiment, the bottom of the intermediate bearing housing includes a shaft hole extending axially along the drive motor, through which a rotating shaft extends into the reducer cavity. The inner diameter of the shaft hole is smaller than the outer diameter of the outer ring of the intermediate bearing, and the inner diameter of the shaft hole is smaller than the inner diameter of the opening of the intermediate bearing housing.

[0014] In this embodiment, the bottom of the intermediate bearing housing includes a shaft hole. The shaft hole extends through the bottom of the intermediate bearing housing along the axial direction of the drive motor, and the third section of the rotating shaft extends through the shaft hole into the reducer cavity. Since the bottom of the intermediate bearing housing needs to abut against one side of the intermediate bearing along the axial direction of the drive motor, the inner diameter of the shaft hole distributed at the bottom of the intermediate bearing housing needs to be smaller than the outer diameter of the outer ring of the intermediate bearing. The inner diameter of the opening of the intermediate bearing housing is larger than the inner diameter of the shaft hole, facilitating the passage of the rotating shaft and the intermediate bearing through the opening of the intermediate bearing housing and avoiding obstruction to the assembly and disassembly of the rotating shaft and the intermediate bearing.

[0015] In one embodiment, the inner diameter of the shaft hole is larger than the outer diameter of the tooth.

[0016] In this embodiment, during the installation of the rotating shaft, the teeth of the rotating shaft pass through the shaft hole of the intermediate bearing housing before the second section. If the outer diameter of the teeth is larger than the inner diameter of the shaft hole, the teeth will be unable to pass through the shaft hole, hindering the installation and disassembly of the rotating shaft and the intermediate bearing.

[0017] In existing spline-fit designs for the motor shaft and input shaft, the motor shaft and input shaft can be installed sequentially in opposite directions, avoiding the problem of the input wheel on the input shaft obstructing the installation of the motor shaft and input shaft. This embodiment integrates the teeth into the third section of the shaft, which extends into the reducer cavity. Unlike existing designs, to apply the shaft to the powertrain, it is necessary to avoid factors that interfere with shaft installation. Therefore, this embodiment adjusts the outer diameter of the teeth to be smaller than the inner diameter of the shaft hole, which helps reduce interference from the teeth on shaft installation, lowering the installation difficulty and cost.

[0018] In one embodiment, the ratio of the inner diameter of the shaft hole to the outer diameter of the tooth is greater than or equal to 1.6.

[0019] In this embodiment, the motor rotor is fixed to the first section of the shaft, and the motor rotor is typically installed synchronously with the shaft. The outer diameter of the motor rotor is larger than the outer diameter of the outer ring of the intermediate bearing. During installation, the larger outer diameter of the motor rotor may obstruct the operator's view. Therefore, this embodiment adjusts the ratio of the inner diameter of the shaft hole to the outer diameter of the teeth to be greater than or equal to 1.6, which reduces the risk of the shaft teeth colliding with the shaft hole during installation.

[0020] In one embodiment, the powertrain housing includes a partition plate distributed along the axial direction of the drive motor between the motor cavity and the reducer cavity. An intermediate bearing housing is distributed within the partition plate.

[0021] The partition plate is used to fix the pressure plate. The pressure plates are distributed along the axial direction of the drive motor on the side of the intermediate bearing away from the teeth, and the pressure plates are used to abut against the partition plate and the outer ring of the intermediate bearing.

[0022] In this embodiment, a partition plate separates the motor cavity and the reducer cavity, and an intermediate bearing housing is distributed on the partition plate. The opening of the intermediate bearing housing along the axial direction of the drive motor faces away from the reducer cavity, and the outer ring of the intermediate bearing abuts against the bottom of the intermediate bearing housing on one side. A pressure plate is distributed on the side of the intermediate bearing facing away from the teeth, and the pressure plate engages with the bottom of the intermediate bearing housing, thus fixing the outer ring of the intermediate bearing on both sides along the axial direction of the drive motor. The pressure plate also abuts against the partition plate, facilitating the fixing of the pressure plate through the partition plate.

[0023] In this embodiment, the pressure plate also prevents the outer ring of the intermediate bearing from slipping. The inner ring of the intermediate bearing is fixed to the shaft, and the outer ring is fixed to the bearing housing. When the inner ring of the intermediate bearing rotates at high speed with the shaft, the rolling elements between the inner and outer rings may cause the outer ring to slide relative to the bearing housing, resulting in slippage of the outer ring. In this embodiment, where the shaft integrates the first, second, and third sections, the pressure plate abuts against the outer ring of the intermediate bearing, which axially limits the outer ring, helping to reduce damage to the intermediate bearing and bearing housing, and improving the lifespan and reliability of the intermediate bearing.

[0024] In one embodiment, the partition plate includes a first surface, a second surface, and a first fixing hole. The first and second surfaces face the motor cavity and the reducer cavity respectively along the axial direction of the drive motor, and the first fixing hole penetrates through the first and second surfaces. The pressure plate includes a second fixing hole.

[0025] In this configuration, the first fixing hole and the second fixing hole are opposite each other along the axial direction of the drive motor. One end of the fixing member of the power assembly extends from the second surface through the first fixing hole into the second fixing hole, and the other end of the fixing member is distributed in the reducer cavity.

[0026] In this embodiment, after the intermediate bearing is installed into the intermediate bearing housing, a fixing member passes through the first and second fixing holes to fix the pressure plate to achieve axial positioning of the outer ring of the intermediate bearing. The motor rotor and the intermediate bearing enter the motor cavity synchronously with the shaft. Along the axial direction of the drive motor, the first and second surfaces of the partition face the motor cavity and the reducer cavity, respectively. If the fixing member is installed in the direction of passing through the first and second surfaces sequentially, the motor rotor and shaft will occupy part of the space in the motor cavity, making it more difficult to pass the fixing member through the partition from the motor cavity. In this embodiment, the installation direction of the fixing member is opposite to the installation direction of the intermediate bearing. One end of the fixing member passes through the second and first surfaces sequentially and then extends into the second fixing hole, which avoids the structure already installed in the motor cavity and helps to reduce the operational difficulty of fixing the pressure plate.

[0027] In this embodiment, before disassembling the shaft and intermediate bearing, the pressure plate needs to be separated from the partition plate using a fixing member. Since the other end of the fixing member is located in the reducer cavity, the disassembly operation of the fixing member passing through the first and second surfaces in sequence can be completed inside the reducer cavity. This helps to avoid structures such as the shaft, motor rotor, and motor stator inside the motor cavity, and simplifies the disassembly process.

[0028] In one embodiment, an opening in the intermediate bearing housing is spaced along the axial direction of the drive motor. A pressure plate includes an annular protrusion extending from the opening into the intermediate bearing housing. One end of the annular protrusion along the axial direction of the drive motor abuts against the outer ring of the intermediate bearing. The intermediate bearing housing is used to secure the outer peripheral surface of the annular protrusion.

[0029] In this embodiment, the pressure plate includes an annular protrusion. One end of the annular protrusion along the axial direction of the drive motor and the bottom of the intermediate bearing housing respectively abut against the two sides of the outer ring of the intermediate bearing. The annular protrusion of the pressure plate extends into the intermediate bearing housing, and the annular protrusion can play a pre-fixing role for the pressure plate. Specifically, before installing the rotating shaft to the housing of the powertrain, the intermediate bearing can be installed on the second section of the rotating shaft first, and then the pressure plate can be sleeved on the rotating shaft, so that the pressure plate is distributed on the side of the intermediate bearing away from the teeth. After the intermediate bearing is installed into the intermediate bearing housing, the annular protrusion of the pressure plate is also embedded in the intermediate bearing housing, which facilitates the subsequent fixation of the pressure plate to the intermediate partition plate using fasteners and prevents the pressure plate from shifting during the fixation process with the intermediate partition plate.

[0030] In one embodiment, the first and third segments are used to fix the inner ring of the motor bearing and the inner ring of the reducer bearing, respectively. One side wall of the reducer cavity along the axial direction of the drive motor is opposite to the central partition. One side wall of the reducer cavity includes a reducer bearing housing, the inner peripheral wall of which is used to fix the outer ring of the reducer bearing. The teeth are adjacent to the opening of the reducer bearing housing.

[0031] The outer ring of the reducer bearing along the axial direction of the drive motor is spaced apart from the bottom of the reducer bearing housing.

[0032] In this embodiment, along the axial direction of the drive motor, one side wall of the reducer cavity is away from the motor rotor. The bearings for fixing the shaft include a motor bearing, an intermediate bearing, and a reducer bearing arranged sequentially along the axial direction of the drive motor. The reducer bearing housing on one side wall of the reducer cavity is used to fix the outer ring of the reducer bearing, and the opening of the reducer bearing housing faces the teeth along the axial direction of the drive motor.

[0033] In this embodiment, since the shaft integrates the function of the input shaft of the reducer, its size and volume are larger than those of the previous motor shaft. Therefore, this embodiment adopts a three-bearing structure, which can use multiple bearings to enhance the support of the shaft and reduce the risk of shaft bending and deformation.

[0034] In this embodiment, the rotating shaft is essentially a single shaft. Using a three-bearing structure on a single shaft may lead to over-positioning. Over-positioning refers to the mechanical interference phenomenon where the same degree of freedom of a workpiece is repeatedly restricted by multiple support points. Over-positioning in a three-bearing structure will exacerbate bearing wear and interfere with torque transmission of the rotating shaft. To reduce the negative impact of over-positioning on the rotating shaft and bearings, this embodiment arranges the reducer bearing and the bottom of the reducer bearing housing at intervals. The gap between the reducer bearing and the reducer bearing housing provides the rotating shaft with axial movement allowance along the drive motor, effectively reducing the constraint of the reducer bearing on the degree of freedom of the rotating shaft's axial movement along the drive motor, thus mitigating the axial over-positioning problem.

[0035] When the axial force generated by the parallel shaft gear set on the shaft is parallel to the direction from the first segment to the second segment, the axial force is directly transmitted to the intermediate partition plate through the intermediate bearing. In this case, since the intermediate partition plate of the powertrain already bears the axial force, the gap between the reducer bearing and the reducer bearing housing will not negatively affect the axial positioning of the shaft. When the axial force generated by the parallel shaft gear set on the shaft is parallel to the direction from the second segment to the first segment, the axial force is transmitted to the intermediate partition plate through the intermediate bearing and the pressure plate. The intermediate partition plate is also used to bear the axial force, which helps to alleviate the axial movement of the shaft and enhance NVH performance. There is an interaction force between the shaft and the pressure plate, which can enhance the rigidity of the shaft and the motor rotor, thereby increasing the critical speed of the shaft. This embodiment adjusts the positional relationship between the reducer bearing and the bottom of the reducer bearing housing without interfering with the axial positioning of the shaft, thus alleviating the problem of axial over-positioning.

[0036] In one embodiment, the distance between the teeth of the drive motor and the intermediate bearing along the axial direction is greater than the distance between the teeth and the reducer bearing. The shaft also serves to fix a first bushing, which abuts against the inner ring of the reducer bearing. The first bushing is distributed between the teeth and the reducer bearing along the axial direction of the drive motor, and the outer diameter of the first bushing is greater than or equal to the outer diameter of the teeth.

[0037] In this embodiment, the axial length of the tooth needs to be adapted to the gears of the parallel shaft gear set; therefore, the axial length of the tooth is usually fixed. Installing a first bushing between the tooth and the inner ring of the reducer bearing compensates for the axial length of the tooth, allowing the inner ring of the reducer bearing to be confined by the first bushing, reducing axial movement of the reducer bearing and the shaft. The outer diameter of the first bushing is greater than or equal to the outer diameter of the tooth, which helps to increase the contact area between the first bushing and the inner ring of the reducer bearing.

[0038] In one embodiment, the radial clearance of the intermediate bearing is greater than the radial clearance of at least one of the motor bearing or the reducer bearing.

[0039] In this embodiment, based on the radial clearance relationship between the motor bearing, the intermediate bearing, and the reducer bearing, the intermediate bearing can be used as a floating end in the radial direction of the drive motor, while the motor bearing and the reducer bearing can be used as fixed ends. This helps to alleviate the problem of radial over-positioning caused by applying a three-bearing structure on the shaft.

[0040] In one embodiment, the first segment is also used to fix two end plates, which are distributed on both sides of the motor rotor along the axial direction of the drive motor. A first shoulder protrudes relative to the first segment along the radial axis of the drive motor. The motor rotor, an end plate, the first shoulder, and the intermediate bearing seat are arranged sequentially along the axial direction of the drive motor, with the first shoulder used to abut against an end plate.

[0041] Among them, the pressure plate along the axial direction of the drive motor is distributed between an end plate and the intermediate bearing, and the length of the end plate along the radial direction of the drive motor is greater than the length of the pressure plate.

[0042] In this embodiment, two end plates are arranged adjacent to each other on both sides of the motor rotor along the axial direction of the drive motor. The shaft includes a first shoulder, the outer diameter of which is larger than the outer diameter of the first section. The first shoulder abuts against one end plate to limit the position of the end plate and the motor rotor. A pressure plate is distributed between one end plate and the intermediate bearing along the axial direction of the drive motor. The radial length of one end plate is greater than the radial length of the pressure plate. Before the pressure plate is fixed to the intermediate partition, the end plate can limit the displacement of the pressure plate, reducing the difficulty of the assembly process.

[0043] In one embodiment, the first segment is also used to secure a second bushing. The second bushing, along the axial direction of the drive motor, abuts against another end plate to secure the motor rotor and the two end plates. The second bushing is located on the side of the other end plate opposite to the pressure plate. The outer diameter of the second bushing is larger than the outer diameter of the first shoulder.

[0044] In this embodiment, the second bushing and the first shoulder are used to abut against the other end plate and the first end plate, respectively. The cooperation between the second bushing and the first shoulder can secure the motor rotor and the two end plates, reducing the axial movement of the motor rotor.

[0045] In this embodiment, the second bushing and the rotating shaft are separate structures. Compared to the first shoulder, the second bushing can be adjusted in position relative to the rotating shaft, the motor rotor, and the other end plate. The relatively large outer diameter of the second bushing is beneficial for increasing the contact area between the second bushing and the other end plate, thereby enhancing the stability of the fixed connection between the motor rotor and the two end plates and the rotating shaft. Since the second bushing is located on the side of the other end plate away from the pressure plate, its larger outer diameter will not interfere with the installation of the rotating shaft, the intermediate bearing, and the pressure plate.

[0046] In one embodiment, a second shoulder protrudes relative to the second section along the radial axis of the drive motor. The second shoulder abuts against one side of the inner ring of the intermediate bearing along the axial direction of the drive motor. The second shoulders are distributed along the axial direction of the drive motor on the side of the second section opposite to the teeth, with a portion of the second shoulders located within the intermediate bearing housing.

[0047] In this embodiment, the second shoulder along the axial direction of the drive motor is used to abut against one side of the intermediate bearing, which can reduce the axial movement of the intermediate bearing relative to the second shoulder, which helps to alleviate the wear of the shaft and the intermediate bearing and improve the working efficiency of the powertrain.

[0048] In this embodiment of the application, from the perspective of avoiding interference with the installation of the rotating shaft, since the outer diameter of the second shoulder is larger than the outer diameter of the second section, the second shoulder needs to be positioned on the side of the second section away from the teeth. This can prevent the second shoulder from hindering the installation operation of fixing the intermediate bearing to the rotating shaft in advance.

[0049] In this embodiment, since the intermediate bearing housing needs to accommodate the annular protrusion of the pressure plate, the axial length of the intermediate bearing housing must be greater than the axial length of the intermediate bearing. To achieve the abutment between the second shoulder and the inner ring of the intermediate bearing, part of the second shoulder is distributed within the intermediate bearing housing, which can prevent the axial length of the second shoulder from being too large.

[0050] In one embodiment, an annular groove along the radial axis of the drive motor is recessed relative to the second section. The annular groove is used to secure a retaining ring, which abuts against the inner ring of the intermediate bearing on the other side along the axial direction of the drive motor. The outer diameter of the retaining ring is larger than the outer diameter of the second section, and the annular groove and the second shoulder are arranged adjacent to each other on both sides of the second section along the axial direction of the drive motor.

[0051] In this embodiment, the second shoulder and the annular groove are distributed on both sides of the second section. The second shoulder and the snap ring accommodated in the annular groove cooperate to achieve axial positioning of the inner ring of the intermediate bearing, which helps to reduce axial movement of the intermediate bearing and the shaft. The annular groove and the teeth are both distributed on the side of the second section away from the first section. Similar to the teeth, the inner diameter of the annular groove needs to be smaller than the outer diameter of the second section. To ensure that the snap ring abuts against the inner ring of the intermediate bearing, the outer diameter of the snap ring needs to be larger than the outer diameter of the second section.

[0052] 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. The powertrain is used to receive power from the power battery and to drive the wheels of the electric vehicle.

[0053] In the embodiments of this application, the powertrain described in any embodiment of the first aspect is applied to an electric vehicle. Since the powertrain's shaft avoids a splined fit structure, noise generation can be reduced, the shaft's service life can be extended, and the NVH performance and safety performance of the electric vehicle can be improved. The intermediate bearing of the powertrain can be installed and disassembled synchronously with the shaft, which helps to reduce the difficulty and cost of disassembly and assembly. Attached Figure Description

[0054] 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.

[0055] Figure 1 This is a schematic diagram of the electric vehicle provided in an embodiment of this application;

[0056] Figure 2This is a schematic diagram of the powertrain provided in an embodiment of this application;

[0057] Figure 3 This is a schematic diagram of the powertrain provided in an embodiment of this application;

[0058] Figure 4 This is a schematic diagram of the rotating shaft provided in an embodiment of this application;

[0059] Figure 5 This is a cross-sectional view of the rotating shaft provided in an embodiment of this application;

[0060] Figure 6 This is a partial schematic diagram of the powertrain provided in an embodiment of this application;

[0061] Figure 7 This is a partial schematic diagram of the powertrain provided in an embodiment of this application;

[0062] Figure 8 This is a partial cross-sectional view of the powertrain provided in the embodiments of this application. Detailed Implementation

[0063] 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.

[0064] For ease of understanding, the English abbreviations and related technical terms used in the embodiments of this application will be explained and described below.

[0065] NVH: An abbreviation for Noise, Vibration, and Harshness, referring to noise, vibration, and acoustic roughness, used to measure the quality of automotive design and manufacturing.

[0066] 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.

[0067] Currently, powertrains face challenges in disassembly and assembly, and their NVH performance needs improvement. This application provides a powertrain embodiment. The powertrain housing includes a motor cavity and a reducer cavity. The motor cavity houses the motor rotor of the drive motor in the powertrain, and the reducer cavity houses the parallel shaft gear set of the reducer in the powertrain. Along the axial direction of the drive motor, the drive motor shaft extends from the motor cavity through an intermediate bearing housing into the reducer cavity.

[0068] The shaft comprises a first section, a second section, and a third section arranged sequentially along the axial direction of the drive motor. The first section is used to fix the motor rotor, the second section is used to fix the inner ring of the intermediate bearing, and the third section has teeth for meshing with the intermediate driven gear of the parallel shaft gear set. The drive motor shaft is connected to the parallel shaft gear set via the teeth. The first section is located in the motor cavity, and the third section is located in the reducer cavity.

[0069] The inner circumferential wall of the intermediate bearing housing is used to fix the outer ring of the intermediate bearing, and the bottom of the intermediate bearing housing along the axial direction of the drive motor is used to abut against the outer ring of the intermediate bearing. The opening of the intermediate bearing housing along the axial direction of the drive motor faces away from the reducer cavity.

[0070] The drive motor shaft of this embodiment has teeth, integrating the function of the reducer's input shaft into the drive motor shaft. This avoids the problems of difficult disassembly and assembly, noise generation, and easy failure associated with the splined fit between the shaft and the input shaft. Furthermore, the opening of the intermediate bearing housing faces away from the reducer cavity, allowing the intermediate bearing to be installed and disassembled synchronously with the shaft, thus reducing disassembly and assembly difficulty and cost. The powertrain provided in this embodiment can be applied to electric vehicles.

[0071] Please see Figure 1 , Figure 1 This is a schematic diagram of an electric vehicle 1 provided in an embodiment of this application. In one embodiment, the electric vehicle 1 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 is used to supply power to the powertrain 10; the power battery 20 can also be called a battery pack. The powertrain 10 is the power source of the electric vehicle 1 and is used to drive the wheels 40 of the electric vehicle 1. In one embodiment, the electric vehicle 1 further includes a frame 30, which is used to mount the powertrain 10 and the power battery 20. The frame 30 is the structural skeleton of the electric vehicle 1 and can withstand the loads from the internal and external environment of the electric vehicle 1.

[0072] Please see Figure 2 , Figure 2 This is a schematic diagram of a powertrain 10 provided in an embodiment of this application. In one embodiment, the powertrain 10 includes a drive motor 100, a motor controller 200, and a reducer 300. A power battery supplies power to the drive motor 100 via the motor controller 200. Specifically, the motor controller 200 converts the direct current supplied by the power battery into alternating current and delivers the alternating current to the drive motor 100. The drive motor 100 is connected to the reducer 300 to drive the wheels to rotate. In one embodiment, the motor controller 200 controls the drive motor 100 and the reducer 300. It should be noted that... Figure 2The diagram only schematically shows the electrical connection between the motor controller 200 of the powertrain 10 and the power battery 20, and the transmission relationship between the drive motor 100 of the powertrain 10 and the reducer 300. It does not represent the actual structure, size, and positional relationship of the powertrain 10, the power battery 20, and the wheels 40.

[0073] The drive motor 100 converts electrical energy into mechanical energy to generate driving torque. In one embodiment, the drive motor 100 includes a shaft 110, a rotor 120, and a stator 130. When alternating current is applied to the windings of the stator 130, alternating magnetic flux is generated. The alternating magnetic flux generated by the windings interacts with the permanent magnet flux generated by the rotor 120, causing the rotor 120 to rotate relative to the stator 130. The rotor 120 is fixedly connected to the shaft 110, allowing the shaft 110 to rotate with the rotor 120. The stator 130 is rotatably connected to the shaft 110, enabling the shaft 110 to rotate relative to the stator 130, thus converting electrical energy into mechanical energy. The shaft 110 transmits mechanical energy to the reducer 300.

[0074] The reducer 300 is used to change the transmission ratio between the drive motor 100 and the wheels. In one embodiment, the reducer 300 includes a parallel shaft gear set 310, an intermediate shaft 320, and a differential 330. The parallel shaft gear set 310 includes an input gear 311, an intermediate driven gear 312, an intermediate driving gear 313, and an output gear 314. The intermediate driven gear 312 and the intermediate driving gear 313 are fixed to the intermediate shaft 320, and the output gear 314 is fixed to the differential 330. The shaft 110 of the drive motor 100 is used to transmit torque to the input gear 311, which engages with the intermediate driven gear 312. The intermediate driven gear 312 drives the intermediate shaft 320 and the intermediate driving gear 313 to rotate. The intermediate driving gear 313 engages with the output gear 314, which drives the differential 330 to rotate. Differential 330 is used to transmit torque to the drive half-shaft to drive the wheels to rotate, enabling the electric vehicle to move forward or backward.

[0075] Currently, powertrains typically utilize the input shaft of a reducer to transmit mechanical energy between the motor shaft of the drive motor and the input wheel. The input shaft and the motor shaft of the drive motor are connected via a spline joint. However, spline joints are difficult to install and remove and can negatively impact the NVH performance of the powertrain. Splines also face the risk of failure due to fretting wear, which is detrimental to improving the efficiency and safety performance of the powertrain and electric vehicles.

[0076] This application embodiment improves the transmission connection structure between the drive motor and the reducer, thereby avoiding the negative impact of splined fit on the powertrain and helping to improve the NVH performance of electric vehicles.

[0077] The powertrain 10 provided in this application is described in detail below.

[0078] Please refer to the following: Figures 2 to 5 , Figure 3 This is a schematic diagram of the powertrain 10 provided in an embodiment of this application. Figure 4 This is a schematic diagram of the rotating shaft 110 provided in an embodiment of this application. Figure 5 This is a cross-sectional view of the rotating shaft 110 provided in an embodiment of this application.

[0079] In one embodiment, the housing of the powertrain 10 includes a motor cavity 400 and a reducer cavity 500. The motor cavity 400 is used to accommodate the motor rotor 120 of the drive motor 100 in the powertrain 10, and the reducer cavity 500 is used to accommodate the parallel shaft gear set 310 of the reducer 300 in the powertrain 10. Along the axial direction of the drive motor 100, the shaft 110 of the drive motor 100 extends from the motor cavity 400 through the intermediate bearing housing 410 into the reducer cavity 500.

[0080] The rotating shaft 110 includes a first section 111, a second section 112, and a third section 113 arranged sequentially along the axial direction O of the drive motor 100. The first section 111 is used to fix the motor rotor 120, the second section 112 is used to fix the inner ring of the intermediate bearing 340, and the third section 113 has teeth 1131 for meshing with the intermediate driven gear 312 of the parallel shaft gear set 310. The first section 111 is located in the motor cavity 400, and the third section 113 is located in the reducer cavity 500.

[0081] The inner peripheral wall of the intermediate bearing housing 410 is used to fix the outer ring of the intermediate bearing 340, and the bottom of the intermediate bearing housing 410 along the axial direction of the drive motor 100 is used to abut against the outer ring of the intermediate bearing 340. The opening of the intermediate bearing housing 410 along the axial direction of the drive motor 100 faces away from the reducer cavity 500.

[0082] In this embodiment of the application, in order to avoid the problems of cumbersome disassembly and assembly, noise and fretting wear caused by the splined connection of the existing motor shaft and input shaft, this embodiment of the application is based on the rotating shaft 110 of the drive motor 100, and integrates the function of the input shaft into the rotating shaft 110, that is, using the rotating shaft 110 to replace the existing combination of the motor shaft and input shaft.

[0083] Specifically, the rotating shaft 110 extends from the motor cavity 400 into the reducer cavity 500. The first section 111 of the rotating shaft 110 is located inside the motor cavity 400, and the third section 113 of the rotating shaft 110 is located inside the reducer cavity 500, providing the prerequisite for the rotating shaft 110 to integrate the function of an input shaft. The first section 111 is used to fix the motor rotor 120, and the rotating shaft 110 itself can directly receive the torque transmitted by the motor rotor 120, thus having the function of a motor shaft. The third section 113 has teeth 1131, which are used to mesh with the intermediate driven gear 312. This means that the teeth 1131 are equivalent to the input gear 311, which is connected to the reducer 300 for transmission. The rotating shaft 110 can directly continue to transmit torque to the reducer 300. Since the shaft 110 avoids the spline fit structure, the embodiments of this application can reduce the difficulty of disassembly and assembly, reduce the noise generated by the shaft 110, improve NVH performance, reduce the risk of failure of the transmission connection between the shaft 110 and the reducer 300, and extend the service life of the shaft 110.

[0084] In this embodiment, in addition to the first segment 111 and the third segment 113, the rotating shaft 110 also includes a second segment 112. The second segment 112 is used to fix the inner ring of the intermediate bearing 340, and the intermediate bearing housing 410 is used to fix the outer ring of the intermediate bearing 340. The intermediate bearing 340 serves to support the rotating shaft 110. The rotating shaft 110 integrates the first segment 111, the second segment 112, and the gear 1131. The first segment 111, the second segment 112, and the gear 1131 can be machined as a single piece, which facilitates meeting the coaxiality requirements. Since the rotating shaft 110 does not need to reserve space for spline mating, it has a high degree of integration, which can shorten the axial dimension of the rotating shaft 110 and help to achieve the miniaturization design of the powertrain 10.

[0085] In this embodiment, the rotating shaft 110 extends from the motor cavity 400 into the reducer cavity 500 through the intermediate bearing seat 410. During the installation and disassembly of the rotating shaft 110, the orientation of the opening of the intermediate bearing seat 410 will affect the difficulty and cost of disassembly and assembly.

[0086] Specifically, if the opening of the intermediate bearing housing 410 faces the reducer cavity 500: during installation, the shaft 110 passes through the bottom and opening of the intermediate bearing housing 410 in sequence, preventing the intermediate bearing 340 from being fixed to the shaft 110 beforehand. Otherwise, it would be blocked by the bottom of the intermediate bearing housing 410, and the intermediate bearing 340 could only be fixed to the intermediate bearing housing 410 first. In this case, the shaft 110 needs to pass through the inner ring of the intermediate bearing 340 during installation, which is prone to collision. The shaft 110 is usually installed synchronously after being fixed with the motor rotor 120. During installation, the position of the intermediate bearing 340 will be blocked by the shaft 110 and the motor rotor 120, increasing the difficulty of ensuring coaxiality. In addition, during the disassembly of the shaft 110, due to the obstruction of the bottom of the intermediate bearing housing 410, the intermediate bearing 340 cannot be removed synchronously with the shaft 110. The intermediate bearing 340 can only be separated from the shaft 110 first, which can easily damage the intermediate bearing 340 during the separation process.

[0087] To reduce the difficulty and cost of disassembling and assembling the powertrain, in this embodiment, when the shaft 110 integrates the first segment 111, the second segment 112, and the third segment 113, the opening of the intermediate bearing housing 410 is adjusted to face away from the reducer cavity 500 along the axial direction O of the drive motor 100. During the installation of the shaft 110, the intermediate bearing 340 can be pre-fixed to the second segment 112 of the shaft 110, so that the intermediate bearing 340 and the shaft 110 can be installed synchronously. Compared with the installation method where the shaft 110 passes through the inner ring of the intermediate bearing 340 during installation, in this embodiment, the shaft 110 and the intermediate bearing 340 simultaneously pass through the opening of the intermediate bearing housing 410 until the outer ring of the intermediate bearing 340 abuts against the bottom of the intermediate bearing housing 410. This simplifies the assembly process and avoids collisions between the intermediate bearing 340 and the shaft 110. Furthermore, during the disassembly of the shaft 110, since the intermediate bearing 340 is not blocked by the bottom of the intermediate bearing housing 410, the intermediate bearing 340 can be detached from the shaft 110 as a whole, which helps to reduce damage to the intermediate bearing 340 and extend the service life of the shaft 110 and the intermediate bearing 340.

[0088] It should be noted that, Figure 3 The diagram only schematically shows the opening orientation of the first section 111, the second section 112, the third section 113 of the rotating shaft 110 and the intermediate bearing housing 410, and does not represent the actual structure and dimensions of the rotating shaft 110, the intermediate bearing 340, and the intermediate bearing housing 410.

[0089] In one embodiment, the mounting and disassembly directions of the rotating shaft 110 are parallel to the direction of gravity.

[0090] In one embodiment, the rotating shaft 110 is a hollow shaft, and the shaft cavity of the rotating shaft 110 can be used to transmit cooling oil to achieve cooling of the drive motor 100 and lubrication of the reducer 300.

[0091] In one embodiment, the shaft cavity of the rotating shaft 110 is also used to accommodate a conductive bearing, which is used to transfer the shaft current of the rotating shaft 110 to the housing of the powertrain 10, thereby grounding the rotating shaft.

[0092] Please continue reading. Figure 3 In one embodiment, the bottom of the intermediate bearing housing 410 includes a shaft hole 411 extending through the axial direction O of the drive motor 100, through which the rotating shaft 110 extends into the reducer cavity 500. The inner diameter of the shaft hole 411 is smaller than the outer diameter of the outer ring of the intermediate bearing 340, and the inner diameter of the shaft hole 411 is smaller than the inner diameter of the opening of the intermediate bearing housing 410.

[0093] In this embodiment, the bottom of the intermediate bearing housing 410 includes a shaft hole 411. The shaft hole 411 extends through the bottom of the intermediate bearing housing 410 along the axial direction O of the drive motor 100. The third segment 113 of the rotating shaft 110 extends through the shaft hole 411 into the reducer cavity 500. Since the bottom of the intermediate bearing housing 410 needs to abut against one side of the intermediate bearing 340 along the axial direction O of the drive motor 100, the inner diameter of the shaft hole 411 distributed at the bottom of the intermediate bearing housing 410 needs to be smaller than the outer diameter of the outer ring of the intermediate bearing 340. The inner diameter of the opening of the intermediate bearing housing 410 is larger than the inner diameter of the shaft hole 411, facilitating the passage of the rotating shaft 110 and the intermediate bearing 340 through the opening of the intermediate bearing housing 410 and avoiding obstruction to the assembly and disassembly of the rotating shaft 110 and the intermediate bearing 340.

[0094] It should be noted that, Figure 3 The diagram only schematically illustrates the size relationship between the inner diameter of the shaft hole 411, the outer diameter of the intermediate bearing 340, and the inner diameter of the opening of the intermediate bearing housing 410. It does not represent the actual dimensions and structure of the shaft hole 411, the intermediate bearing 340, and the intermediate bearing housing 410.

[0095] Please continue reading. Figure 3 In one embodiment, the inner diameter of the shaft hole 411 is larger than the outer diameter of the tooth 1131.

[0096] In this embodiment of the application, during the installation of the rotating shaft 110, the teeth 1131 of the rotating shaft 110 pass through the shaft hole 411 of the intermediate bearing housing 410 before the second segment 112. If the outer diameter of the teeth 1131 is larger than the inner diameter of the shaft hole 411, the teeth 1131 will be unable to pass through the shaft hole 411, hindering the installation and disassembly of the rotating shaft 110 and the intermediate bearing 340.

[0097] In existing spline-fit designs for motor shafts and input shafts, the motor shaft and input shaft can be installed sequentially in opposite directions, avoiding the problem of the input wheel of the input shaft obstructing the installation of the motor shaft and input shaft. In this embodiment, the toothed portion 1131 is integrated into the third segment 113 of the rotating shaft 110, which extends into the reducer cavity 500. Unlike existing designs, to apply the rotating shaft 110 to the powertrain 10, it is necessary to avoid factors that interfere with the installation of the rotating shaft 110. Therefore, in this embodiment, the outer diameter of the toothed portion 1131 is adjusted to be smaller than the inner diameter of the shaft hole 411, which helps to reduce the interference of the toothed portion 1131 on the installation of the rotating shaft 110, reducing the installation difficulty and cost of the rotating shaft 110.

[0098] It should be noted that, Figure 3 The diagram only schematically illustrates the size relationship between the inner diameter of the shaft hole 411 and the outer diameter of the tooth 1131, and does not represent the actual size and structure of the tooth 1131.

[0099] In one embodiment, the ratio of the inner diameter of the shaft hole 411 to the outer diameter of the tooth 1131 is greater than or equal to 1.6.

[0100] In this embodiment, the motor rotor 120 is fixed to the first section 111 of the rotating shaft 110, and the motor rotor 120 is typically installed synchronously with the rotating shaft 110. The outer diameter of the motor rotor 120 is larger than the outer diameter of the outer ring of the intermediate bearing 340. During installation, the larger outer diameter of the motor rotor 120 may obstruct the operator's view. Therefore, in this embodiment, the ratio of the inner diameter of the shaft hole 411 to the outer diameter of the tooth 1131 is adjusted to be greater than or equal to 1.6, which reduces the risk of the tooth 1131 of the rotating shaft 110 colliding with the shaft hole 411 during installation.

[0101] Please continue reading. Figure 3 In one embodiment, the inner diameter of the shaft bore 411 is larger than the outer diameter of the inner ring of the intermediate bearing 340.

[0102] In this embodiment, the inner ring of the intermediate bearing 340 is fixed to the rotating shaft 110. When the power assembly 10 is in operation, the inner ring of the intermediate bearing 340 rotates at high speed relative to the intermediate bearing housing 410 along with the rotating shaft 110. If the inner diameter of the shaft hole 411 is less than or equal to the outer diameter of the inner ring of the intermediate bearing 340, it is equivalent to the bottom of the intermediate bearing housing 410 abutting against both the outer and inner rings of the intermediate bearing 340, which can easily lead to friction between the inner ring of the intermediate bearing 340 and the intermediate bearing housing 410. This embodiment, by adjusting the size relationship between the inner diameter of the shaft hole and the outer diameter of the inner ring of the intermediate bearing 340, helps to reduce the wear of the intermediate bearing 340 and the intermediate bearing housing 410, and improves their service life.

[0103] Please continue reading. Figure 3 In one embodiment, the powertrain 10 housing includes a partition 800, which is distributed along the axial direction of the drive motor 100 between the motor cavity 400 and the reducer cavity 500. An intermediate bearing housing 410 is distributed within the partition 800. The partition 800 serves to fix a pressure plate 370. Along the axial direction of the drive motor 100, the pressure plate 370 is distributed on the side of the intermediate bearing 340 opposite to the tooth portion 1131, and the pressure plate 370 abuts against the partition 800 and the outer ring of the intermediate bearing 340.

[0104] In this embodiment, a partition 800 separates the motor cavity 400 and the reducer cavity 500, and an intermediate bearing housing 410 is distributed on the partition 800. Along the axial direction O of the drive motor 100, the opening of the intermediate bearing housing 410 faces away from the reducer cavity 500, and the outer ring of the intermediate bearing 340 abuts against the intermediate bearing housing 410 on one side facing the bottom of the intermediate bearing housing 410. A pressure plate 370 is distributed on the side of the intermediate bearing 340 facing away from the tooth portion 1131. The pressure plate 370 engages with the bottom of the intermediate bearing housing 410, fixing the outer ring of the intermediate bearing 340 on both sides along the axial direction O of the drive motor 100. The pressure plate 370 also abuts against the partition 800, facilitating the fixing of the pressure plate 370 through the partition 800.

[0105] In this embodiment, the pressure plate 370 can also prevent the outer ring of the intermediate bearing 340 from running out of its race. The inner ring of the intermediate bearing 340 is fixed to the rotating shaft 110, and the outer ring of the intermediate bearing 340 is fixed to the intermediate bearing housing 410. When the inner ring of the intermediate bearing 340 is rotating at high speed with the rotating shaft 110, the rolling elements located between the inner and outer rings of the intermediate bearing 340 may cause the outer ring of the intermediate bearing 340 to slide relative to the intermediate bearing housing 410, causing the outer ring of the intermediate bearing 340 to run out of its race. In this embodiment, when the rotating shaft 110 integrates the first segment 111, the second segment 112, and the third segment 113, the pressure plate 370 abuts against the outer ring of the intermediate bearing 340, which can axially limit the outer ring of the intermediate bearing 340, helping to reduce damage to the intermediate bearing 340 and the intermediate bearing housing 410, and improving the life and reliability of the intermediate bearing 340.

[0106] It should be noted that, Figure 3 The relative positions of the pressure plate 370 and the intermediate bearing housing 410 are shown only schematically, and the pressure plate 370 is used to abut against the outer ring of the partition plate 800 and the intermediate bearing 340. For clarity, the pressure plate 370 has been simplified and does not represent the actual structure and dimensions of the pressure plate 370.

[0107] Please refer to the following: Figure 3 , Figure 6 and Figure 7 , Figure 6 This is a partial schematic diagram of the powertrain 10 provided in an embodiment of this application. Figure 7 This is a partial schematic diagram of the powertrain 10 provided in an embodiment of this application. In one embodiment, the partition plate 800 includes a first surface 810, a second surface 820, and a first fixing hole 830. Along the axial direction of the drive motor 100, the first surface 810 and the second surface 820 face the motor cavity 400 and the reducer cavity 500, respectively, and the first fixing hole 830 penetrates through the first surface 810 and the second surface 820. The pressure plate 370 includes a second fixing hole 372. The first fixing hole 830 and the second fixing hole 372 are opposite each other along the axial direction of the drive motor 100. Along the axial direction of the drive motor 100, one end of the fixing member 101 of the powertrain 10 extends from the second surface 820 through the first fixing hole 830 into the second fixing hole 372, and the other end of the fixing member 101 is distributed in the reducer cavity 500.

[0108] In this embodiment, after the intermediate bearing 340 is installed into the intermediate bearing housing 410, the pressure plate 370 is fixed to the partition plate 800 by the fastener 101 passing through the first fixing hole 830 and the second fixing hole 372, thereby achieving axial positioning of the outer ring of the intermediate bearing 340. The motor rotor 120 and the intermediate bearing 340 enter the motor cavity 400 synchronously with the shaft 110. Along the axial direction of the drive motor 100, the first surface 810 and the second surface 820 of the partition plate 800 face the motor cavity 400 and the reducer cavity 500, respectively. If the fastener 101 is installed in the direction of passing through the first surface 810 and the second surface 820 in sequence, the motor rotor 120 and the shaft 110 will occupy part of the space in the motor cavity 400, which will increase the difficulty of passing the fastener 101 from the motor cavity 400 through the partition plate 800. In this embodiment, the mounting direction of the fastener 101 is opposite to the mounting direction of the intermediate bearing 340. One end of the fastener 101 passes through the second surface 820 and the first surface 810 in sequence and extends into the second fixing hole 372, which can avoid the structure that has been installed in the motor cavity 400 and helps to reduce the operational difficulty of fixing the pressure plate 370.

[0109] In this embodiment, before disassembling the shaft 110 and the intermediate bearing 340, the pressure plate 370 needs to be separated from the partition plate 800 using the fixing member 101. Since the other end of the fixing member 101 is located in the reducer cavity 500, the disassembly operation of the fixing member 101 passing through the first surface 810 and the second surface 820 in sequence can be completed within the reducer cavity 500. This helps to avoid structures such as the shaft 110, motor rotor 120, and motor stator 130 within the motor cavity 400, and simplifies the disassembly process.

[0110] In one embodiment, the partition plate 800 includes a plurality of first fixing holes 830, which are evenly distributed along the circumference of the powertrain 10. The pressure plate 370 includes a plurality of second fixing holes 372, which are evenly distributed along the circumference of the powertrain 10. It should be noted that the specific number of the first fixing holes 830 and the specific number of the second fixing holes 372 are not limited in this embodiment, as long as each first fixing hole 830 is opposite to one second fixing hole 372 along the axial direction O of the powertrain 10, so that a fastener 101 passes through the first fixing hole 830 and the second fixing hole 372.

[0111] In one embodiment, the fastener 101 is a screw, and the pressure plate 370 is fixed to the partition plate 800 by means of screw connection.

[0112] Please continue reading. Figure 3 , Figure 6 and Figure 7 In one embodiment, the intermediate bearing 340 is spaced apart from the opening of the intermediate bearing housing 410 along the axial direction O of the drive motor 100. The pressure plate 370 includes an annular protrusion 371 that extends from the opening of the intermediate bearing housing 410 into the intermediate bearing housing 410. One end of the annular protrusion 371 along the axial direction O of the drive motor 100 abuts against the outer ring of the intermediate bearing 340. The intermediate bearing housing 410 is used to fix the outer peripheral surface of the annular protrusion 371.

[0113] In this embodiment, the pressure plate 370 includes an annular protrusion 371. One end of the annular protrusion 371 and the bottom of the intermediate bearing housing 410 abut against the two sides of the outer ring of the intermediate bearing 340, respectively, along the axial direction of the drive motor 100. The annular protrusion 371 of the pressure plate 370 extends into the intermediate bearing housing 410, and the annular protrusion 371 can play a pre-fixing role for the pressure plate 370. Specifically, before installing the rotating shaft 110 into the housing of the power assembly 10, the intermediate bearing 340 can be installed on the second section 112 of the rotating shaft 110 first, and then the pressure plate 370 can be sleeved on the rotating shaft 110, so that the pressure plate 370 is distributed on the side of the intermediate bearing 340 away from the toothed portion 1131. After the intermediate bearing 340 is installed into the intermediate bearing housing 410, the annular protrusion 371 of the pressure plate 370 is also embedded in the intermediate bearing housing 410, which facilitates the subsequent fixation of the pressure plate 370 to the intermediate partition 800 using the fastener 101, and prevents the pressure plate 370 from shifting during the fixation process with the intermediate partition 800.

[0114] Please continue reading. Figure 3In one embodiment, the first segment 111 and the third segment 113 are used to fix the inner ring of the motor bearing 160 and the inner ring of the reducer bearing 360, respectively. Along the axial direction of the drive motor 100, one side wall of the reducer cavity 500 is opposite to the partition plate 800. One side wall of the reducer cavity 500 includes a reducer bearing housing 610, the inner peripheral wall of which is used to fix the outer ring of the reducer bearing 360. The toothed portion 1131 is adjacent to the opening of the reducer bearing housing 610. Along the axial direction of the drive motor 100, the outer ring of the reducer bearing 360 is spaced from the bottom of the reducer bearing housing 610.

[0115] In this embodiment, along the axial direction O of the drive motor 100, one side wall of the reducer cavity 500 is away from the motor rotor 120. For example... Figure 3 As shown, in one embodiment, one side wall of the reducer cavity 500 is a reducer end cover 600. In this embodiment, the bearings fixed to the shaft 110 include a motor bearing 160, an intermediate bearing 340, and a reducer bearing 360 arranged sequentially along the axial direction O of the drive motor 100. In one embodiment, the inner rings of the motor bearing 160, the intermediate bearing 340, and the reducer bearing 360 are respectively interference-fitted with the first section 111, the second section 112, and the third section 113 of the shaft 110. The reducer bearing seat 610 of the reducer end cover 600 is used to fix the outer ring of the reducer bearing 360, and the opening of the reducer bearing seat 610 faces the tooth portion 1131 along the axial direction O of the drive motor 100.

[0116] In this embodiment, since the shaft 110 integrates the function of the input shaft of the reducer 300, its size and volume are larger than those of the previous motor shaft. Therefore, this embodiment adopts a three-bearing structure, which can use multiple bearings to enhance the support of the shaft 110 and reduce the risk of bending deformation of the shaft 110.

[0117] In this embodiment, the rotating shaft 110 is essentially a single shaft. Using a three-bearing structure on a single shaft may lead to over-positioning. Over-positioning refers to the mechanical interference phenomenon where the same degree of freedom of a workpiece is repeatedly restricted by multiple support points. Over-positioning in a three-bearing structure will exacerbate bearing wear and interfere with torque transmission of the rotating shaft 110. To reduce the negative impact of over-positioning on the rotating shaft 110 and bearings, this embodiment arranges the reducer bearing 360 and the reducer bearing housing 610 at intervals at the bottom. The gap between the reducer bearing 360 and the reducer bearing housing 610 provides the rotating shaft 110 with sufficient margin to move along the axial direction O of the drive motor 100. This effectively reduces the constraint of the reducer bearing 360 on the degree of freedom of the rotating shaft 110 to move along the axial direction O of the drive motor 100, thus mitigating the problem of axial over-positioning.

[0118] like Figure 3As shown, in one embodiment, the powertrain 10 housing includes an intermediate housing 900, with a partition plate 800 distributed within the intermediate housing 900. A reducer end cover 600 is fixed to the intermediate housing 900 along the axial direction of the drive motor 100. The intermediate housing 900, together with the reducer end cover 600, forms a reducer cavity 500. When the direction of the axial force generated by the parallel shaft gear set on the rotating shaft 110 is parallel to the direction from the first segment 111 to the second segment 112, the axial force is directly transmitted to the partition plate 800 through the intermediate bearing 340. In this case, since the intermediate housing 900 of the powertrain 10 already bears the axial force, the gap between the reducer bearing 360 and the reducer bearing housing 610 will not negatively affect the axial positioning of the rotating shaft 110. When the axial force generated by the parallel shaft gear set on the rotating shaft 110 is parallel to the direction from the second segment 112 to the first segment 111, the axial force is transmitted to the intermediate partition 800 through the intermediate bearing 340 and the pressure plate 370. The intermediate housing 900 also bears the axial force, which helps to alleviate the axial movement of the rotating shaft 110 and enhance NVH performance. There is an interaction force between the rotating shaft 110 and the pressure plate 370, which can enhance the rigidity of the rotating shaft 110 and the motor rotor 120, thereby increasing the critical speed of the rotating shaft 110. In this embodiment, the positional relationship between the reducer bearing 360 and the bottom of the reducer bearing housing 610 is adjusted without interfering with the axial positioning of the rotating shaft 110, thus alleviating the problem of axial over-positioning.

[0119] like Figure 3 As shown, in one embodiment, the powertrain 10 housing includes a motor end cover 700, a reducer end cover 600, and the motor end cover 700 distributed on both sides of the intermediate housing 900 along the axial direction O of the drive motor 100. The motor end cover 700 is fixed to the intermediate housing 900 along the axial direction O of the drive motor 100. The intermediate housing 900 and the motor end cover 700 form a motor cavity 400. The motor end cover 700 includes a motor bearing housing 710. The inner peripheral wall of the motor bearing housing 710 is used to fix the outer ring of the motor bearing 160. The opening of the motor bearing housing 710 faces the motor rotor 120 along the axial direction O of the drive motor 100.

[0120] It should be noted that, Figure 3 The reducer bearing housing 610, motor bearing housing 710, reducer end cover 600, motor end cover 700 and intermediate housing 900 are shown only schematically and do not represent the actual structure and size of the reducer bearing housing 610, motor bearing housing 710, reducer end cover 600, motor end cover 700 and intermediate housing 900.

[0121] In one embodiment, the motor bearing housing 710, the intermediate bearing housing 410, and the reducer bearing housing 610 are all groove-shaped structures.

[0122] Please refer to the following: Figures 6 to 8 , Figure 8 This is a partial cross-sectional view of the powertrain 10 provided in an embodiment of this application. In one embodiment, the distance between the tooth 1131 and the intermediate bearing 340 along the axial direction O of the drive motor 100 is greater than the distance between the tooth 1131 and the reducer bearing 360. The rotating shaft 110 is also used to fix a first bushing 380, which abuts against the inner ring of the reducer bearing 360. The first bushing 380 is distributed between the tooth 1131 and the reducer bearing 360 along the axial direction O of the drive motor 100, and the outer diameter of the first bushing 380 is greater than or equal to the outer diameter of the tooth 1131.

[0123] In this embodiment, the axial length of the tooth 1131 needs to be adapted to the gear of the parallel shaft gear set, therefore the axial length of the tooth 1131 is usually fixed. Installing a first bushing 380 between the tooth 1131 and the inner ring of the reducer bearing 360 can compensate for the axial length of the tooth 1131, allowing the inner ring of the reducer bearing 360 to be limited by the first bushing 380, reducing axial movement of the reducer bearing 360 and the shaft 110. The outer diameter of the first bushing 380 is greater than or equal to the outer diameter of the tooth 1131, which helps to increase the contact area between the first bushing 380 and the inner ring of the reducer bearing 360.

[0124] In one embodiment, the radial clearance of the intermediate bearing 340 is greater than the radial clearance of at least one of the motor bearing 160 or the reducer bearing 360.

[0125] In this embodiment, based on the radial clearance relationship between the motor bearing 160, the intermediate bearing 340, and the reducer bearing 360, the intermediate bearing 340 can serve as a floating end in the radial direction R of the drive motor 100, while the motor bearing 160 and the reducer bearing 360 can serve as fixed ends. This helps alleviate the radial over-positioning problem caused by applying a three-bearing structure to the shaft 110. In one embodiment, the radial clearance of the intermediate bearing 340 is greater than the radial clearance of either the motor bearing 160 or the reducer bearing 360. In another embodiment, the radial clearance of at least one of the reducer bearing 360 or the intermediate bearing 340 is greater than the radial clearance of the motor bearing 160.

[0126] Please refer to the following: Figures 6 to 8In one embodiment, the first segment 111 is also used to fix two end plates 140, which are distributed on both sides of the motor rotor 120 along the axial direction of the drive motor 100. A first shoulder 114 protrudes from the first segment 111 along the radial direction of the drive motor 100. The motor rotor 120, one end plate 140, the first shoulder 114, and the intermediate bearing seat 410 are arranged sequentially along the axial direction of the drive motor 100. The first shoulder 114 abuts against one end plate 140. A pressure plate 370 is distributed between one end plate 140 and the intermediate bearing 340 along the axial direction of the drive motor 100. The length of one end plate 140 is greater than the length of the pressure plate 370 along the radial direction of the drive motor 100.

[0127] In this embodiment, two end plates 140 are arranged adjacent to each other on both sides of the motor rotor 120 along the axial direction O of the drive motor 100. In one embodiment, the two end plates 140 can serve to achieve dynamic balance of the motor rotor 120.

[0128] In this embodiment, for ease of description, one end plate 140 is referred to as end plate 140a. In this embodiment, the rotating shaft 110 includes a first shoulder 114, the outer diameter of which is larger than the outer diameter of the first segment 111. The first shoulder 114 abuts against the end plate 140a to limit the position of the end plate 140a and the motor rotor 120. Along the axial direction of the drive motor 100, pressure plates 370 are distributed between the end plate 140a and the intermediate bearing 340. The radial length of the end plate 140a is greater than the radial length of the pressure plates 370. Before the pressure plates 370 are fixed to the intermediate partition 800, the end plate 140a can limit the displacement of the pressure plates 370, reducing the difficulty of the assembly process.

[0129] Please continue reading. Figures 6 to 8 In one embodiment, the first segment 111 is also used to fix the second bushing 150. Along the axial direction of the drive motor 100, the second bushing 150 abuts against another end plate 140 to fix the motor rotor 120 and the two end plates 140. The second bushing 150 is distributed on the side of the other end plate 140 opposite to the pressure plate 370. The outer diameter of the second bushing 150 is larger than the outer diameter of the first shoulder 114.

[0130] In this embodiment of the application, for ease of description, the other end plate 140 is referred to as end plate 140b. The second bushing 150 and the first shoulder 114 are used to abut against end plate 140b and end plate 140a, respectively. The cooperation between the second bushing 150 and the first shoulder 114 can fasten the motor rotor 120 and the two end plates 140, reducing the axial movement of the motor rotor 120.

[0131] In this embodiment, the second bushing 150 and the rotating shaft 110 are separate structures. Compared to the first shoulder 114, the second bushing 150 can be adjusted in position relative to the rotating shaft 110, the motor rotor 120, and the end plate 140b. The relatively large outer diameter of the second bushing 150 is beneficial for increasing the contact area between the second bushing 150 and the end plate 140b, thereby enhancing the stability of the fixed connection between the motor rotor 120 and the two end plates 140 and the rotating shaft 110. Since the second bushing 150 is located on the side of the end plate 140b away from the pressure plate 370, the large outer diameter of the second bushing 150 will not interfere with the installation of the rotating shaft 110, the intermediate bearing 340, and the pressure plate 370.

[0132] Please refer to the following: Figure 3 and Figure 8 In one embodiment, a second shoulder 116 protrudes relative to the second segment 112 along the radial R shaft 110 of the drive motor 100. The second shoulder 116 abuts against one side of the inner ring of the intermediate bearing 340 along the axial direction O of the drive motor 100. The second shoulder 116 is distributed along the axial direction O of the drive motor 100 on the side of the second segment 112 opposite to the tooth 1131, and a portion of the second shoulder 116 is distributed within the intermediate bearing housing 410.

[0133] In this embodiment, the second shoulder 116 along the axial direction of the drive motor 100 is used to abut against one side of the intermediate bearing 340, which can reduce the axial movement of the intermediate bearing 340 relative to the second shoulder 116, which helps to alleviate the wear of the shaft 110 and the intermediate bearing 340 and improve the working efficiency of the powertrain 10.

[0134] In this embodiment, from the perspective of avoiding interference with the installation of the rotating shaft 110, since the outer diameter of the second shoulder 116 is larger than the outer diameter of the second segment 112, the second shoulder 116 needs to be positioned on the side of the second segment 112 away from the tooth 1131, so as to avoid the second shoulder 116 from hindering the installation operation of fixing the intermediate bearing 340 to the rotating shaft 110 in advance.

[0135] In this embodiment, since the intermediate bearing housing 410 needs to accommodate the annular protrusion 371 of the pressure plate 370, the axial length of the intermediate bearing housing 410 needs to be greater than the axial length of the intermediate bearing 340. To achieve the abutment between the second shoulder 116 and the inner ring of the intermediate bearing 340, part of the second shoulder 116 is distributed within the intermediate bearing housing 410, which can prevent the axial length of the second shoulder 116 from being too large.

[0136] Please continue reading. Figure 5 , Figure 7 and Figure 8In one embodiment, an annular groove 115 along the radial R of the drive motor 100 shaft 110 is recessed relative to the second segment 112. The annular groove 115 is used to secure a retaining ring 350, which abuts against the inner ring of the intermediate bearing 340 on the other side along the axial direction O of the drive motor 100. The outer diameter of the retaining ring 350 is larger than the outer diameter of the second segment 112, and the annular groove 115 and the second shoulder 116 are arranged adjacent to each other on both sides of the second segment 112 along the axial direction O of the drive motor 100.

[0137] In this embodiment, the second shoulder 116 and the annular groove 115 are distributed on both sides of the second segment 112. The second shoulder 116 and the snap ring 350 accommodated in the annular groove 115 cooperate to achieve axial positioning of the inner ring of the intermediate bearing 340, which helps to reduce the axial movement of the intermediate bearing 340 and the rotating shaft 110. The annular groove 115 and the tooth 1131 are both distributed on the side of the second segment 112 away from the first segment 111. Similar to the tooth 1131, the inner diameter of the annular groove 115 needs to be smaller than the outer diameter of the second segment 112. To ensure that the snap ring 350 abuts against the inner ring of the intermediate bearing 340, the outer diameter of the snap ring 350 needs to be larger than the outer diameter of the second segment 112. In one embodiment, the snap ring 350 can be installed into the annular groove 115 after the rotating shaft 110 and the intermediate bearing 340 are installed.

[0138] The following describes the installation method of the powertrain provided in the embodiments of this application.

[0139] The motor stator is heat-fitted into the motor cavity, fixing it to the cavity wall. After heating the reducer cavity, the intermediate shaft and the outer ring of the differential tapered bearing are installed. The intermediate bearing is press-fitted into the second section of the shaft, and the pressure plate is inserted between the first shoulder and the intermediate bearing. The motor rotor, two end plates, second bushing, motor bearing, resolver rotor, and the first section of the shaft are press-fitted, and the conductive bearing is press-fitted into the shaft cavity. The shaft is installed into the motor cavity from the drive motor side. The intermediate bearing is press-fitted into the reducer housing until it is completely flush with the bottom. The retaining element is locked from the reducer side to secure the pressure plate to the partition plate. A retaining ring is installed in the annular groove. The first bushing and the reducer-side bearing are installed into the third section of the shaft. A wave washer is installed in the motor bearing housing, the motor end cover is assembled with the motor cavity, and the resolver stator is installed into the motor end cover. A gasket is installed in the reducer bearing housing of the reducer end cover. Install an intermediate shaft with tapered bearings and a differential into the reducer cavity, and then assemble the reducer end cover with the reducer cavity.

[0140] 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 methods 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 housing includes a motor cavity and a reducer cavity. The motor cavity is used to accommodate the motor rotor of the drive motor in the powertrain, and the reducer cavity is used to accommodate the parallel shaft gear set of the reducer in the powertrain. Along the axial direction of the drive motor, the shaft of the drive motor extends from the motor cavity through the intermediate bearing seat into the reducer cavity. The rotating shaft includes a first section, a second section, and a third section arranged sequentially along the axial direction of the drive motor. The first section is used to fix the motor rotor, the second section is used to fix the inner ring of the intermediate bearing, and the third section has teeth for meshing with the intermediate driven gear of the parallel shaft gear set. The first section is located in the motor cavity, and the third section is located in the reducer cavity. The inner peripheral wall of the intermediate bearing housing is used to fix the outer ring of the intermediate bearing. The bottom of the intermediate bearing housing along the axial direction of the drive motor is used to abut against the outer ring of the intermediate bearing. The opening of the intermediate bearing housing along the axial direction of the drive motor faces away from the reducer cavity.

2. The powertrain according to claim 1, characterized in that, The bottom of the intermediate bearing housing includes a shaft hole that extends through the drive motor along the axial direction. The rotating shaft passes through the shaft hole and extends into the reducer cavity. The inner diameter of the shaft hole is smaller than the outer diameter of the outer ring of the intermediate bearing, and the inner diameter of the shaft hole is smaller than the inner diameter of the opening of the intermediate bearing housing.

3. The powertrain according to claim 2, characterized in that, The inner diameter of the shaft hole is larger than the outer diameter of the tooth.

4. The powertrain according to claim 3, characterized in that, The ratio of the inner diameter of the shaft hole to the outer diameter of the tooth is greater than or equal to 1.

6.

5. The powertrain according to any one of claims 1-4, characterized in that, The powertrain housing includes a partition plate, which is distributed between the motor cavity and the reducer cavity along the axial direction of the drive motor. An intermediate bearing housing is distributed within the partition plate, wherein: The partition plate is used to fix the pressure plate. The pressure plate is distributed along the axial direction of the drive motor on the side of the intermediate bearing away from the teeth. The pressure plate is used to abut against the partition plate and the outer ring of the intermediate bearing.

6. The powertrain according to claim 5, characterized in that, The partition plate includes a first surface, a second surface, and a first fixing hole. Along the axial direction of the drive motor, the first surface and the second surface face the motor cavity and the reducer cavity, respectively. The first fixing hole penetrates both the first surface and the second surface. The pressure plate includes a second fixing hole, wherein: Along the axial direction of the drive motor, the first fixing hole and the second fixing hole are opposite each other. Along the axial direction of the drive motor, one end of the fixing member of the power assembly passes through the first fixing hole from the second surface and extends into the second fixing hole, and the other end of the fixing member is distributed in the reducer cavity.

7. The powertrain according to claim 5, characterized in that, The intermediate bearing and the intermediate bearing housing are spaced apart along the axial direction of the drive motor. The pressure plate includes an annular protrusion that extends from the opening of the intermediate bearing housing into the intermediate bearing housing. One end of the annular protrusion along the axial direction of the drive motor is used to abut against the outer ring of the intermediate bearing. The intermediate bearing housing is used to fix the outer peripheral surface of the annular protrusion.

8. The powertrain according to claim 5, characterized in that, The first segment and the third segment are respectively used to fix the inner ring of the motor bearing and the inner ring of the reducer bearing. Along the axial direction of the drive motor, one side wall of the reducer cavity is opposite to the partition plate. The one side wall of the reducer cavity includes a reducer bearing housing. The inner peripheral wall of the reducer bearing housing is used to fix the outer ring of the reducer bearing. The teeth are adjacent to the opening of the reducer bearing housing. Wherein: The outer ring of the reducer bearing is spaced apart from the bottom of the reducer bearing housing along the axial direction of the drive motor.

9. The powertrain according to claim 8, characterized in that, Along the axial direction of the drive motor, the distance between the tooth and the intermediate bearing is greater than the distance between the tooth and the reducer bearing. The rotating shaft is also used to fix the first bushing, which is used to abut against the inner ring of the reducer bearing. Along the axial direction of the drive motor, the first bushing is distributed between the tooth and the reducer bearing, and the outer diameter of the first bushing is greater than or equal to the outer diameter of the tooth.

10. The powertrain according to claim 8, characterized in that, The radial clearance of the intermediate bearing is greater than the radial clearance of at least one of the motor bearing or the reducer bearing.

11. The powertrain according to any one of claims 6-10, characterized in that, The first segment is also used to fix two end plates, which are distributed on both sides of the motor rotor along the axial direction of the drive motor. A first shoulder of the rotating shaft protrudes relative to the first segment along the radial direction of the drive motor. The motor rotor, one end plate, the first shoulder, and the intermediate bearing seat are arranged sequentially along the axial direction of the drive motor. The first shoulder is used to abut against the one end plate. Wherein: The pressure plate is distributed between the end plate and the intermediate bearing along the axial direction of the drive motor, and the length of the end plate along the radial direction of the drive motor is greater than the length of the pressure plate.

12. The powertrain according to claim 11, characterized in that, The first section is also used to fix the second bushing. Along the axial direction of the drive motor, the second bushing is used to abut against another end plate to fix the motor rotor and the two end plates. The second bushing is distributed on the side of the other end plate away from the pressure plate. The outer diameter of the second bushing is larger than the outer diameter of the first shoulder.

13. The powertrain according to any one of claims 1-4, 6-10, and 12, characterized in that, The second shoulder of the rotating shaft protrudes relative to the second section along the radial direction of the drive motor. The second shoulder is used to abut against one side of the inner ring of the intermediate bearing along the axial direction of the drive motor. The second shoulder is distributed on the side of the second section away from the teeth along the axial direction of the drive motor, and part of the second shoulder is distributed in the intermediate bearing housing.

14. The powertrain according to claim 13, characterized in that, The annular groove of the rotating shaft along the radial direction of the drive motor is recessed relative to the second section. The annular groove is used to fix the retaining ring. The retaining ring is used to abut against the inner ring of the intermediate bearing on the other side along the axial direction of the drive motor. The outer diameter of the retaining ring is larger than the outer diameter of the second section. Along the axial direction of the drive motor, the annular groove and the second shoulder are arranged adjacent to each other on both sides of the second section.

15. The powertrain according to claim 5, characterized in that, The first segment is also used to fix two end plates, which are distributed on both sides of the motor rotor along the axial direction of the drive motor. A first shoulder of the rotating shaft protrudes relative to the first segment along the radial direction of the drive motor. The motor rotor, one end plate, the first shoulder, and the intermediate bearing seat are arranged sequentially along the axial direction of the drive motor. The first shoulder is used to abut against the one end plate. Wherein: The pressure plate is distributed between the end plate and the intermediate bearing along the axial direction of the drive motor, and the length of the end plate along the radial direction of the drive motor is greater than the length of the pressure plate.

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

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