Driving motor, power assembly and electric vehicle
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HUAWEI TECH CO LTD
- Filing Date
- 2025-12-31
- Publication Date
- 2026-05-15
Smart Images
Figure CN122052360A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of motor technology, and more particularly to a drive motor, powertrain, and electric vehicle. Background Technology
[0002] In a drive motor, the stator core is installed onto the stator housing via a heat-shrink process. During assembly, the stator housing applies compressive stress to the stator core. Excessive compressive stress can affect the magnetic properties of the stator core, leading to increased excitation current, reduced efficiency, and even additional iron losses in the drive motor, severely impacting its performance and reliability.
[0003] Currently, the protrusions on the outer periphery of the stator core are embedded in the grooves on the inner periphery of the stator housing to achieve installation positioning and overcome tangential forces. However, this disrupts the symmetry of the stator magnetic circuit, which may cause magnetic field distortion, leading to increased torque pulsation and vibration noise problems. Summary of the Invention
[0004] This application provides a drive motor, powertrain, and electric vehicle for reducing the impact of stator core assembly on motor performance.
[0005] To achieve the above objectives, this application adopts the following technical solution:
[0006] A first aspect of this application provides a drive motor for driving an electric vehicle. The drive motor includes a stator housing and a stator core. The stator housing is used to house and fix the stator core. The stator core includes an annular portion, a plurality of radial protrusions, and a plurality of axial openings. Each radial protrusion protrudes radially along the drive motor and is fixedly connected to the outer periphery of the annular portion. The plurality of radial protrusions are spaced apart circumferentially along the drive motor, and each radial protrusion is used to fit into a groove on the inner periphery of the stator housing. Each axial opening is located in at least one of the radial protrusions and the annular portion.
[0007] In the drive motor provided in this application, each radial protrusion is embedded in the groove on the inner circumference of the stator housing to achieve precise positioning of the stator core within the stator housing and to resist the load and vibration caused by the alternating component of the tangential magnetic pull during the operation of the drive motor, thereby preventing relative displacement and vibration amplification between the stator core and the stator housing.
[0008] Each axial opening is distributed in at least one of the radial protrusions and the annular portion. The axial openings are used to cut off the transmission path of the compressive stress from the stator housing to the stator core, so as to disperse the compressive stress and avoid local concentration of compressive stress that would affect the performance of the drive motor.
[0009] In one embodiment, the cross-sectional shape of the radial protrusion has a smaller dimension along the radial direction of the drive motor than its dimension along the circumferential direction of the drive motor.
[0010] In the drive motor provided in this application, the cross-sectional shape of the radial protrusion refers to the cross-sectional profile shape exposed after the radial protrusion is cut along an axial direction perpendicular to the stator core.
[0011] When the drive motor is running, the torsional force on the stator core is circumferential. By designing the cross-sectional shape of the radial protrusion to have a small radial dimension and a large circumferential dimension, it has a larger shear resistance area when subjected to circumferential tangential force, making it less likely to be sheared or damaged. Furthermore, the small radial dimension of the cross-sectional shape of the radial protrusion helps to reduce the impact on the symmetry of the magnetic circuit within the stator core.
[0012] In one embodiment, the size of the radial protrusion along the circumferential direction of the drive motor is smaller than the distance between two adjacent radial protrusions.
[0013] In the drive motor provided in this application, the circumferential dimension of the radial protrusion is small and the circumferential spacing between two adjacent radial protrusions is large, so as to avoid the superposition of stress fields between two adjacent radial protrusions, prevent the appearance of continuous stress bands in the circumference of the stator core, ensure the flatness of the stator core laminations, and help improve the uniformity of the magnetic circuit.
[0014] In one embodiment, the cross-sectional shape of the axial opening has a radial dimension smaller than the circumferential dimension of the drive motor.
[0015] In the drive motor provided in this application, the cross-sectional shape of the axial opening refers to the cross-sectional profile shape exposed after the axial opening is cut along the axial direction perpendicular to the stator core.
[0016] Under the compressive stress of the stator housing on the stator core, the radial protrusion undergoes elastic deformation by designing the cross-sectional shape of the axial opening with a small radial dimension and a large circumferential dimension. This absorbs and disperses the local assembly stress between the stator housing and the stator core. Furthermore, when the groove in the stator housing generates significant compressive stress on the radial protrusion, the axial opening with a flat cross-section, featuring a small radial dimension and a large circumferential dimension, acts as a buffer, thus resolving the problem of high compressive assembly stress between the stator housing and the stator core.
[0017] In one embodiment, a portion of the axial opening is formed on the outer peripheral surface of the annular portion, and another portion of the axial opening is formed on the radial protrusion.
[0018] In the drive motor provided in this application, since the radial protrusion directly bears the compressive stress applied by the stator housing, the compressive stress transmission path inside the stator core is cut off by opening an axial hole, so as to prevent the excessive compressive stress between the stator core and the stator housing from affecting the magnetic properties of the stator core.
[0019] Furthermore, the radial protrusions increase the magnetic cross-sectional area of the stator core, disrupting the uniformity of the axial magnetic circuit cross-sectional area and causing local abrupt changes in magnetic reluctance and magnetic field disturbances. By subtracting the increased magnetic cross-sectional area due to the radial protrusions through axial openings, the magnetic reluctance is uniformly distributed along the circumferential direction of the drive motor. This results in a simpler path, a smoother magnetic field path, and effectively reduces the risk of magnetic leakage.
[0020] In one embodiment, the area of the cross-section of the axial opening located on the annular portion is different from the area of the cross-section of the axial opening located on the radial protrusion.
[0021] In some embodiments, the area of the cross-section of the axial opening located on the annular portion is greater than the area of the cross-section of the axial opening located on the radial protrusion.
[0022] Since the radial protrusion is a component that bears compressive stress and circumferential tangential force, by making the area of the axial opening on the cross-section of the radial protrusion small, the material of the radial protrusion is preserved to the maximum extent, ensuring the torsional strength of the radial protrusion and reducing the weakening of the radial protrusion's strength due to the opening of the axial opening.
[0023] By utilizing the large cross-sectional area of the axially oriented opening in the annular portion, a controllable high magnetoresistivity region is formed on the annular portion. This high magnetoresistivity region serves two purposes: firstly, it forms a diagonal or symmetrical relationship with the low magnetoresistivity region formed by the radial protrusions, thus counteracting the magnetic circuit effects of both and improving the uniformity of magnetic flux distribution throughout the circumference, mitigating the local concentration of magnetic flux caused by the addition of radial protrusions; secondly, it provides a buffer for the additional magnetic flux concentrated at the radial protrusions, reducing the risk of local saturation at the radial protrusions.
[0024] In other embodiments, the area of the axial opening located in the cross-section of the annular portion is smaller than the area of the axial opening located in the cross-section of the radial protrusion, so as to reduce the impact on the structural strength of the annular portion under the condition that the radial protrusion undergoes elastic deformation.
[0025] In one embodiment, the shape of the cross-section of the axial opening located on the annular portion is different from the shape of the cross-section of the axial opening located on the radial protrusion, in order to meet different requirements.
[0026] Specifically, by designing the shape of the cross-section of the axial opening located in the annular part to conform to the direction of magnetic flux flow and guide the magnetic flux lines to wind around with a smooth profile, interference with the magnetic circuit is reduced, ensuring the overall smoothness of magnetic flux flow.
[0027] By designing the shape of the cross-section of the axial opening located on the radial protrusion, the radial protrusion can generate controllable elastic deformation while ensuring its strength and rigidity, so as to absorb and disperse the local assembly stress during the press-fitting of the stator core and stator housing.
[0028] In one embodiment, the cross-sectional shape of the axial opening located on the annular portion along the radial direction of the drive motor is different from the cross-sectional shape of the axial opening located on the radial protrusion along the radial direction of the drive motor.
[0029] In some embodiments, the cross-sectional shape of the axial opening located on the annular portion along the radial direction of the drive motor is larger than the cross-sectional shape of the axial opening located on the radial protrusion along the radial direction of the drive motor.
[0030] The axial opening located in the annular section has a large radial dimension in its cross-section to form a wider and smoother magnetic bridge channel in the radial direction. This helps the magnetic flux lines to redistribute around the axial opening, preventing extreme magnetic concentration and local saturation in narrow areas. The axial opening located in the radial protrusion has a small radial dimension in its cross-sectional shape to ensure the structural strength of the radial protrusion.
[0031] In some embodiments, the cross-sectional shape of the axial opening located on the annular portion along the radial direction of the drive motor is smaller than the cross-sectional shape of the axial opening located on the radial protrusion along the radial direction of the drive motor.
[0032] The axial opening located on the annular section has a small radial dimension in its cross-sectional shape to minimize its impact on the structural strength of the annular section. The axial opening located on the radial protrusion has a large radial dimension in its cross-sectional shape to ensure that the radial protrusion undergoes elastic deformation under compressive stress.
[0033] In one embodiment, the axial opening includes a first section of hole wall and a second section of hole wall, which are distributed relative to each other along the radial direction of the drive motor. The distance between the first section of hole wall and the central axis of the drive motor is greater than the distance between the second section of hole wall and the central axis of the drive motor. The first section of hole wall is further away from the central axis of the drive motor, while the second section of hole wall is closer to the central axis of the drive motor.
[0034] The first section of the hole wall has a U-shaped cross-section to guide the radial protrusions to deform and release stress under compressive stress. This concentrates the compressive stress in the deformable area of the stator core, preventing the compressive stress during the assembly of the stator core and stator housing from being transmitted to the annular part of the stator core, thus reducing the impact on the stator core during the assembly process.
[0035] The cross-sectional shape of the second section of the hole wall is arc-shaped, so that it conforms to the direction of magnetic flux flow and guides the magnetic flux lines to wind around with a smooth contour, thereby reducing interference to the magnetic circuit and ensuring the overall smoothness of magnetic flux flow.
[0036] In one embodiment, the radial protrusion includes a first portion and a second portion, which are distributed along the circumference of the drive motor on both sides of the axial opening. The dimension of either the first portion or the second portion along the circumference of the drive motor is larger than the dimension of the axial opening along the radial direction of the drive motor, so as to ensure the structural strength of the radial protrusion and improve its ability to resist the circumferential tangential force during motor operation.
[0037] In one embodiment, the radial protrusion further includes a third portion, which, along with the annular portion, is distributed radially on both sides of the axial opening of the drive motor. The radial dimension of the third portion is smaller than the radial dimension of the axial opening of the drive motor, so that the third portion can undergo controllable elastic deformation to absorb and disperse local assembly stress during the press-fitting of the stator core and stator housing.
[0038] In one embodiment, the radial dimension of the third part along the drive motor is smaller than the circumferential dimension of either the first or second part along the drive motor. This ensures that the third part produces controllable elastic deformation to absorb and disperse local assembly stress during the press-fitting of the stator core and stator housing. On the other hand, it ensures the structural strength of the radial protrusion and improves the ability of the radial protrusion to resist circumferential tangential forces during motor operation.
[0039] In one embodiment, the radial dimension of the third part along the drive motor is smaller than the radial dimension of either the first part or the second part along the drive motor, so as to ensure that the third part produces controllable elastic deformation and reduce the impact of compressive stress during stator core assembly on motor performance.
[0040] A second aspect of this application provides a powertrain including a reducer and the aforementioned drive motor, the drive motor being used to drive the wheels of an electric vehicle via the reducer.
[0041] The drive motor converts electrical energy into rotational mechanical energy and outputs torque to the reducer. The reducer reduces the rotational speed, increases the torque, and then transmits the power.
[0042] The powertrain provided in this application includes the aforementioned drive motor. Therefore, the powertrain provided in this application solves the same technical problem and has the same technical effect as the drive motor of the aforementioned technical solution, and will not be repeated here.
[0043] A third aspect of this application provides an electric vehicle including wheels and the aforementioned powertrain for driving the wheels.
[0044] The drive motor of the powertrain is used to convert electrical energy into mechanical energy and drive the wheels to rotate through a reducer, thereby enabling the electric vehicle to move.
[0045] The electric vehicle provided in this application includes the aforementioned powertrain. Therefore, the electric vehicle provided in this application solves the same technical problem and has the same technical effect as the powertrain of the aforementioned technical solution, and will not be repeated here. Attached Figure Description
[0046] Figure 1 This is a schematic diagram of the structure of an electric vehicle provided in an embodiment of this application;
[0047] Figure 2 This is a schematic diagram of the structure of a powertrain provided in an embodiment of this application;
[0048] Figure 3 This is a schematic diagram of the structure of a drive motor provided in an embodiment of this application;
[0049] Figure 4 A partial structural schematic diagram of a drive motor provided in an embodiment of this application;
[0050] Figure 5 for Figure 4 A magnified view of the S1 position in the middle;
[0051] Figure 6 A three-dimensional structural diagram of a stator core provided for an embodiment of this application;
[0052] Figure 7 This is a schematic diagram of the structure of a stator core provided in an embodiment of this application;
[0053] Figure 8 for Figure 7 A magnified view of the S2 position in the middle;
[0054] Figure 9 One of the partial structural schematic diagrams of a stator core provided in the embodiments of this application;
[0055] Figure 10 A second partial structural schematic diagram of a stator core provided for an embodiment of this application;
[0056] Figure 11 This is the third partial structural schematic diagram of a stator core provided in the embodiments of this application.
[0057] Figure label:
[0058] 1000-Electric vehicle; 100-Powertrain; 200-Wheel; 300-Power battery; 10-Drive motor; 20-Reducer; 1-Rotor; 2-Stator; 21-Stator core; 211-Annular part; 2111-Outer circumferential surface; 212-Radial protrusion; 2121-First part; 2122-Second part; 2123-Third part; 213-Axial opening; 2131-First section hole wall; 2132-Second section hole wall; 22-Stator winding; 3-Motor shaft; 4-Stator housing; 41-Groove; 411-Slot opening; 412-Slot bottom wall; 413-Slot side wall. Detailed Implementation
[0059] In the accompanying drawings of the embodiments of this application, solid structures such as parts and components are represented by guide lines; hollow structures such as openings, holes, spaces, and cavities are represented by guide lines with arrows.
[0060] The stator core is installed onto the stator housing via a heat-shrink process. During assembly, the stator housing applies compressive stress to the stator core. Excessive compressive stress can affect the magnetic properties of the stator core, leading to increased excitation current, reduced efficiency, and even additional iron losses such as harmonics, localized pulsations, and eddy currents in structural components, severely impacting motor performance and reliability. Some existing solutions use protrusions on the outer circumference of the stator core to fit into grooves on the inner circumference of the stator housing to achieve installation positioning and overcome tangential forces. However, this disrupts the symmetry of the stator magnetic circuit, potentially causing magnetic field distortion, resulting in increased torque pulsation and vibration noise problems.
[0061] Based on this, this application provides a drive motor for reducing the impact of stator core assembly on motor performance.
[0062] The drive motor provided in this application is used in powertrains and electric vehicles with powertrains, which helps to improve the overall vehicle performance.
[0063] The electric vehicle provided in this application is a wheeled device driven or towed by a power unit. In some embodiments, the electric vehicle includes pure electric vehicles, hybrid electric vehicles, range-extended electric vehicles, or plug-in hybrid electric vehicles, etc.
[0064] Among them, pure electric vehicles are called battery electric vehicles, abbreviated as BEV. Hybrid electric vehicles are called hybrid electric vehicles, abbreviated as HEV. Range-extended electric vehicles are called range-extended electric vehicles, abbreviated as REEV. Plug-in hybrid electric vehicles are called plug-in hybrid electric vehicles, abbreviated as PHEV.
[0065] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.
[0066] Figure 1 This is a structural schematic diagram of an electric vehicle provided as an embodiment of this application. (Refer to...) Figure 1 The electric vehicle 1000 includes a powertrain 100 and wheels 200. The powertrain 100 is used to drive the wheels 200 to rotate, thereby enabling the electric vehicle 1000 to move.
[0067] The electric vehicle 1000 also includes a power battery 300. The power battery 300 is used to supply power to the powertrain 100, and is also referred to as a battery pack. The powertrain 100 is used to convert the electrical energy provided by the power battery 300 into mechanical energy to drive the wheels 200 to rotate, thereby enabling the electric vehicle 1000 to move.
[0068] Figure 2 This is a schematic diagram of a powertrain provided in an embodiment of this application. (Refer to...) Figure 2 The portion shown in the dashed box is the powertrain 100. The powertrain 100 includes a drive motor 10 and a reducer 20. The drive motor 10 converts electrical energy into mechanical energy, and then transmits the mechanical energy to the reducer 20. The reducer 20 converts the mechanical energy output by the drive motor 10 into a greater torque output to drive the wheels 200 to rotate.
[0069] Figure 3 This is a schematic diagram of a drive motor provided in an embodiment of this application. (Refer to...) Figure 3 The drive motor 10 includes a rotor 1 and a stator 2. The rotor 1 passes through the center hole of the stator 2 along direction A. The stator 2 surrounds the rotor 1 along direction B. Direction A is the axial direction of the drive motor 10, and direction B is the circumferential direction of the drive motor 10.
[0070] The stator 2 and rotor 1 work together to convert electrical energy into mechanical energy. The stator 2 includes a stator core 21 and a stator winding 22, with the winding 22 mounted on the core 21. When energized, the stator winding 22 generates a rotating magnetic field. This rotating magnetic field interacts with the inherent magnetic field of the rotor 1's magnets, generating an electromagnetic force. This electromagnetic force acting on the rotor 1 is converted into driving torque, which drives the rotor 1 to rotate, thus achieving the conversion of electrical energy into mechanical energy.
[0071] The motor shaft 3 passes through the center hole of the rotor 1 along direction A. The motor shaft 3 is fixed to the center hole of the rotor 1, so the motor shaft 3 rotates together with the rotor 1. The motor shaft 3 is used to transmit the rotational torque generated by the rotor 1, thereby outputting mechanical energy.
[0072] In this application, the axial direction of the drive motor 10, the axial direction of the stator 2, and the axial direction of the stator core 21 are the same, and are referred to by the letter A. The circumferential direction of the drive motor 10, the circumferential direction of the stator 2, and the circumferential direction of the stator core 21 are the same, and are referred to by the letter B. The radial direction of the drive motor 10, the radial direction of the stator 2, and the radial direction of the stator core 21 are the same, and are referred to by the letter C.
[0073] exist Figure 3 In the given embodiment, the drive motor 10 further includes a stator housing 4, which is used to accommodate and fix the stator core 21. The stator core 21 is embedded into the stator housing 4 by means of a heat-fitting process or the like.
[0074] Figure 4 This is a partial structural diagram of a drive motor provided in an embodiment of this application. Figure 5 for Figure 4 A magnified view of the S1 position. (Refer to...) Figure 4 and Figure 5 The inner circumference of the stator housing 4 includes a plurality of grooves 41, which are spaced apart along the B direction, with the opening 411 of each groove 41 facing the stator core 21. The stator core 21 includes an annular portion 211 and a plurality of radial protrusions 212. Figure 3 The rotor 1 passes through the central hole of the annular portion 211. The central hole of the annular portion 211 is indicated by the letter a.
[0075] The number of radial protrusions 212 is the same as the number of grooves 41 and they correspond one-to-one. Each radial protrusion 212 is used to fit into a groove 41 on the inner circumference of the stator housing 4.
[0076] Each radial protrusion 212 is embedded in the groove 41 on the inner circumference of the stator housing 4 to achieve precise positioning of the stator core 21 within the stator housing 4, and to resist the load and vibration caused by the alternating component of the tangential magnetic pull during the operation of the drive motor, thereby preventing relative displacement and vibration amplification between the stator core 21 and the stator housing 4.
[0077] The alternating component of the tangential magnetic pull refers to the force component in the tangential magnetic pull that fluctuates periodically with time or rotor position, distinct from the constant component that provides stable drive torque. It is one of the causes of motor torque pulsation and NVH (Noise, Vibration, Harshness). NVH stands for Noise, Vibration, and Harshness.
[0078] In some embodiments, the annular portion 211 and the plurality of radial protrusions 212 are integrally formed structural components.
[0079] In the drive motor 10 provided in this application, there is a gap between the outer peripheral surface 2111 of the annular portion 211 and the inner periphery of the stator housing 4, and the end of the radial protrusion 212 along the C direction is interference-fitted with the bottom wall 412 of the groove 41. The two ends of the radial protrusion 212 along the B direction are respectively clearance-fitted or transition-fitted with the side wall 413 of the corresponding groove 41.
[0080] The stator core 21 is composed of multiple layers of laminated laminations, which are not shown in the accompanying drawings of this application. Compared to the overall interference fit between the inner circumference of the stator housing 4 and the outer circumference of the stator core 21, the interference fit between the end of the radial protrusion 212 along the C direction and the bottom wall 412 of the groove 41 reduces the interference contact area between the stator housing 4 and the stator core 21. This limits the range of compressive stress exerted by the stator housing 4 on the stator core 21, prevents deformation of the laminated laminations in the stator core 21, improves magnetic conductivity, and prevents magnetic leakage.
[0081] The radial protrusions 212, with their ends in the B direction respectively engaging with the corresponding groove sidewalls 413 of the groove 41 via clearance or transition fit, provide precise circumferential positioning for the stator housing 4 and stator core 21. There is no compressive stress along the B direction, effectively overcoming the tangential force during motor operation and preventing deformation of the laminations in the stator core 21, thus helping to reduce eddy current losses. Furthermore, they are also used to compensate for circumferential machining errors or assembly errors, making assembly smoother and improving assembly efficiency.
[0082] Figure 6 This is a three-dimensional structural diagram of a stator core provided in an embodiment of this application. (Refer to...) Figure 6 The stator core 21 is a cylindrical core. Multiple radial protrusions 212 are distributed around the outer periphery of the annular portion 211 of the stator core 21 along the B direction. Each radial protrusion 212 protrudes along the corresponding C direction, and each radial protrusion 212 is fixedly connected to the outer periphery of the annular portion 211. The multiple radial protrusions 212 are spaced apart along the B direction.
[0083] In this application, reference is made to Figure 6 The stator core 21 includes a plurality of axial openings 213. Each axial opening 213 is distributed in at least one of the radial protrusions 212 and the annular portion 211. Cutting is achieved using the axial openings 213. Figure 4 The transmission path of compressive stress from the stator housing 4 to the stator core 21 is designed to disperse the compressive stress and avoid local concentration of compressive stress that could affect the performance of the drive motor.
[0084] In some embodiments, the axial opening 213 extends through the entire stator core 21 along direction A, and the size of the axial opening 213 along direction A is equal to the size of the stator core 21 along direction A. In some embodiments, the size of the axial opening 213 along direction A is smaller than the size of the stator core 21 along direction A.
[0085] Each axial opening 213 is distributed in at least one of the radial protrusions 212 and the annular portion 211, including three embodiments:
[0086] One embodiment is that a portion of each axial opening 213 is formed in the annular portion 211, and another portion of the axial opening 213 is formed in the radial protrusion 212.
[0087] One embodiment is that each axial opening 213 is formed on a radial protrusion 212.
[0088] One embodiment is that each axial opening 213 is distributed in the annular portion 211.
[0089] Below, this application will provide a more detailed description of three embodiments of this application in conjunction with the accompanying drawings.
[0090] Figure 7 This is a schematic diagram of a stator core provided in an embodiment of this application. Figure 8 for Figure 7 A magnified view of the S2 position in the middle. (Refer to...) Figure 7 and Figure 8 Each axial opening 213 has a portion formed on the outer peripheral surface 2111 of the annular portion 211, and another portion formed on the radial protrusion 212. A portion of the axial opening 213 is as follows: Figure 8 The other part of the axial opening, as indicated by the letter 'c', is as follows: Figure 8 The letter d in the middle refers to.
[0091] Because the radial protrusion 212 directly bears the load Figure 5 The compressive stress applied to the stator housing 4 is cut off by opening an axial opening 213 to cut off the compressive stress transmission path inside the stator core 21, so as to prevent the excessive compressive stress between the stator core 21 and the stator housing 4 from affecting the magnetic properties of the stator core 21.
[0092] Furthermore, the radial protrusion 212 increases the magnetic cross-sectional area of the stator core 21, disrupting the uniformity of the axial magnetic circuit cross-sectional area and leading to local abrupt changes in magnetic reluctance and magnetic field disturbances. By subtracting the increased magnetic cross-sectional area from the radial protrusion 212 through the axial opening 213, the magnetic reluctance is uniformly distributed along the B direction, resulting in a simpler and smoother magnetic field path, effectively reducing the risk of magnetic leakage. It also contributes to the symmetry of the stator core 21's magnetic circuit, preventing magnetic field distortion that could lead to increased torque pulsation and vibration noise.
[0093] In some embodiments, refer to Figure 7 Along direction B, the size of the radial protrusion 212 is smaller than the distance between two adjacent radial protrusions 212.
[0094] The radial protrusions 212 have small circumferential dimensions and large circumferential spacing between two adjacent radial protrusions 212 to avoid the superposition of stress fields between two adjacent radial protrusions 212, prevent continuous stress bands in the circumference of the stator core 21, ensure the flatness of the laminations in the stator core 21, and help improve the uniformity of the magnetic circuit.
[0095] Figure 9 This is one of the partial structural schematic diagrams of a stator core provided in an embodiment of this application. (Refer to...) Figure 9 The dotted line indicates the outer circumferential surface 2111 of the stator core 21, and each axial opening 213 is distributed on the radial protrusion 212.
[0096] Because the radial protrusion 212 directly bears the load Figure 5 The compressive stress applied to the stator housing 4 is prevented from being transmitted to the annular portion 211 by cutting off the compressive stress transmission path inside the radial protrusion 212 through the axial opening 213 in the radial protrusion 212, thus preventing excessive compressive stress from affecting the magnetic properties of the stator core 21.
[0097] Furthermore, the axial openings 213 are distributed on the radial protrusions 212, which will not affect the structural strength of the annular portion 211, nor will they affect the magnetic conductivity of the annular portion 211, thus preventing the risk of magnetic leakage caused by the openings in the annular portion 211.
[0098] In addition, drilling holes in the radial protrusions 212 is easier and less difficult to achieve, and will not increase the processing steps and assembly difficulty of the stator core 21.
[0099] Figure 10 This is a second partial structural schematic diagram of a stator core provided in an embodiment of this application. (Refer to...) Figure 10 The dotted line indicates the outer circumferential surface 2111 of the stator core 21, and each axial opening 213 is distributed in the annular portion 211.
[0100] By opening an axial hole 213 in the annular portion 211, space is reserved for elastic deformation of the annular portion 211 to counteract the deformation caused by… Figure 5 The compressive stress transmitted by the stator shell 4 is prevented from being too large and affecting the magnetic properties of the stator core 21.
[0101] Furthermore, the stator core 21 generates heat due to eddy currents during operation. The heat dissipation channel is formed through the axial opening 213, which accelerates the heat dissipation of the stator core 21 and helps to reduce the temperature rise of the stator core 21, thereby improving the operating efficiency and thermal stability of the drive motor.
[0102] exist Figure 8 , Figure 9 and Figure 10In the given embodiment, the cross-sectional shape of the radial protrusion 212 has a dimension along the C direction that is smaller than its dimension along the B direction. The cross-sectional shape of the radial protrusion 212 refers to the shape of the exposed cross-sectional profile after the radial protrusion 212 is cut along a direction perpendicular to A.
[0103] When the drive motor is running, the torsional force on the stator core 21 is circumferential. By designing the cross-sectional shape of the radial protrusion 212 to have a small radial dimension and a large circumferential dimension, it has a larger shear resistance area when subjected to circumferential tangential force, making it less likely to be sheared or damaged. Furthermore, the small radial dimension of the cross-sectional shape of the radial protrusion 212 helps to reduce the impact on the symmetry of the magnetic circuit within the stator core 21.
[0104] In some scenarios, the cross-sectional shape of the radial protrusion 212 has a small dimension along the C direction, and correspondingly, Figure 4 The shallow depth of the groove 41 on the inner circumference of the stator housing 4 reduces the weakening of the stiffness and strength of the stator housing 4 itself.
[0105] In some embodiments, refer to Figure 8 , Figure 9 and Figure 10 The cross-sectional shape of the axial opening 213 has a smaller dimension along the C direction than that along the B direction. The cross-sectional shape of the axial opening 213 refers to the shape of the exposed cross-sectional profile after the axial opening 213 is cut along a direction perpendicular to A.
[0106] exist Figure 4 Under the compressive stress of the stator housing 4 on the stator core 21, the radial protrusion 212 undergoes elastic deformation by designing the cross-sectional shape of the axial opening 213 to have a small radial dimension and a large circumferential dimension, so as to absorb and disperse the local assembly stress between the stator housing 4 and the stator core 21.
[0107] Furthermore, when the groove 41 of the stator housing 4 generates a large compressive stress on the radial protrusion 212, an axial opening 213 with a flat cross-section that has a small radial dimension and a large circumferential dimension is designed to play a buffering role, thus solving the problem of large extrusion assembly stress between the stator housing 4 and the stator core 21.
[0108] Below, this application will further describe the embodiments of the present application by taking as an example that a portion of each axial opening 213 is formed on the outer peripheral surface 2111 of the annular portion 211 and another portion of the axial opening 213 is formed on the radial protrusion 212.
[0109] In some embodiments, refer to Figure 8 The area of the axial opening 213 located in the cross-section of the annular portion 211 is different from the area of the axial opening 213 located in the cross-section of the radial protrusion 212.
[0110] The cross-section of the axial opening 213 located in the annular portion 211 refers to the cross-section of the axial opening 213 located in a part of the annular portion 211 along a direction perpendicular to the axial direction of the stator core 21.
[0111] The cross section of the axial opening 213 located on the radial protrusion 212 refers to the cross section of the other part of the axial opening 213 located on the radial protrusion 212 along the direction perpendicular to the axial direction of the stator core 21.
[0112] This includes two embodiments, one of which is: referring to Figure 8 The cross-sectional area of the axial opening 213 located on a part of the annular portion 211 is greater than the cross-sectional area of the axial opening 213 located on the other part of the radial protrusion 212.
[0113] Since the radial protrusion 212 is a component that bears compressive stress and circumferential tangential force, by making the cross-sectional area of the axial opening 213 located in a part of the radial protrusion 212 small, the material of the radial protrusion 212 is preserved to the maximum extent, ensuring the torsional strength of the radial protrusion 212 and reducing the weakening of the strength of the radial protrusion 212 due to the opening of the axial opening 213.
[0114] The axial opening 213, located on a portion of the annular portion 211, has a large cross-sectional area, forming a controllable high magnetoresistivity region on the annular portion 211. This high magnetoresistivity region serves two purposes: firstly, it forms a diagonal or symmetrical relationship with the low magnetoresistivity region formed by the radial protrusion 212, thus counteracting the magnetic circuit effects of both and improving the uniformity of magnetic flux distribution throughout the circumference, mitigating the local concentration of magnetic flux caused by the addition of the radial protrusion 212; secondly, it provides a buffer for the additional magnetic flux concentrated at the radial protrusion 212, reducing the risk of local saturation at the radial protrusion 212.
[0115] In some embodiments, the plurality of axial openings 213 in the stator core 21 are used to deliver cooling oil, thereby forming a plurality of cooling channels on the stator core 21 to improve the heat dissipation capacity of the stator core 21, and thus improve the heat dissipation capacity of the stator. The axial openings 213 located in the annular portion 211 have a large cross-sectional area to further improve the heat dissipation capacity of the stator.
[0116] Another embodiment is: refer to Figure 11 The cross-sectional area of the axial opening 213 located on a part of the annular portion 211 is smaller than the cross-sectional area of the axial opening 213 located on the other part of the radial protrusion 212, so as to reduce the impact on the structural strength of the annular portion 211 when the radial protrusion 212 is subjected to compressive stress and elastic deformation.
[0117] In some embodiments, refer to Figure 8 and Figure 11The shape of the cross section of the axial opening 213 located on a part of the annular portion 211 is different from the shape of the cross section of the axial opening 213 located on another part of the radial protrusion 212, in order to meet different requirements.
[0118] Specifically, by designing the shape of the cross-section of the axial opening 213 located in a part of the annular portion 211 to conform to the direction of magnetic flux flow and guide the magnetic flux line to wind around with a smooth profile, the interference to the magnetic circuit is reduced, ensuring the overall smoothness of magnetic flux flow.
[0119] By designing the cross-sectional shape of the axial opening 213 located on the other part of the radial protrusion 212, the radial protrusion 212 is made to generate controllable elastic deformation while ensuring its strength and rigidity, so as to absorb and disperse the stator core 21 and Figure 4 The local assembly stress during the press-fitting process of the stator housing 4.
[0120] In some embodiments, refer to Figure 8 and Figure 11 The cross-sectional shape of the axial opening 213 located in a part of the annular portion 211 along the C direction is different from the cross-sectional shape of the axial opening 213 located in another part of the radial protrusion 212 along the C direction.
[0121] This includes two embodiments, one of which is: Refer to Figure 8 The radial dimension of the cross-sectional shape of the axial opening 213 located on a part of the annular portion 211 is greater than the radial dimension of the cross-sectional shape of the axial opening 213 located on the other part of the radial protrusion 212 along the drive motor 10.
[0122] The axial opening 213, located on a portion of the annular portion 211, has a large radial dimension in its cross-sectional shape to form a wider and smoother magnetic bridge channel in the radial direction. This helps the magnetic flux lines to redistribute around the axial opening 213, preventing extreme magnetic concentration and local saturation in narrow areas. The axial opening 213, located on another portion of the radial protrusion 212, has a small radial dimension in its cross-sectional shape to ensure the structural strength of the radial protrusion 212.
[0123] Another embodiment is: refer to Figure 11 The radial dimension of the cross-sectional shape of the axial opening 213 located on a part of the annular portion 211 is smaller than the dimension of the cross-sectional shape of the axial opening 213 located on the other part of the radial protrusion 212 along the C direction.
[0124] The axial opening 213 is located on a portion of the annular portion 211 with a small radial dimension in its cross-section to reduce its impact on the structural strength of the annular portion 211. The axial opening 213 is located on another portion of the radial protrusion 212 with a large radial dimension to ensure that the radial protrusion 212 undergoes elastic deformation under compressive stress.
[0125] In some embodiments, refer to Figure 8 and Figure 11 The axial opening 213 includes a first hole wall 2131 and a second hole wall 2132. The first hole wall 2131 and the second hole wall 2132 are distributed relative to each other along the C direction. The distance between the first hole wall 2131 and the central axis of the drive motor 10 is greater than the distance between the second hole wall 2132 and the central axis of the drive motor 10. The central axis of the drive motor 10 is as follows: Figure 6 The letter 'b' in the text refers to.
[0126] The first section of the hole wall 2131 is further away from the central axis or central hole of the drive motor, while the second section of the hole wall 2132 is closer to the central axis or central hole of the drive motor.
[0127] The first section of the hole wall 2131 has a U-shaped cross-section to guide the radial protrusion 212 to deform under compressive stress and release stress. This concentrates the compressive stress in the deformable area of the stator core 21, preventing the compressive stress during the assembly of the stator core 21 and the stator housing 4 from being transmitted to the annular part 211 of the stator core 21, thus reducing the impact on the stator core 21 during the assembly of the stator core 21 and the stator housing 4.
[0128] The cross-sectional shape of the second section of the hole wall 2132 is arc-shaped, so that it conforms to the direction of magnetic flux flow and guides the magnetic flux lines to wind around with a smooth contour, thereby reducing interference to the magnetic circuit and ensuring the overall smoothness of magnetic flux flow.
[0129] In some embodiments, refer to Figure 8 and Figure 11 The radial protrusion 212 includes a first part 2121 and a second part 2122, which are distributed along the B direction on both sides of the axial opening 213. The dimension of either the first part 2121 or the second part 2122 along the B direction is greater than the dimension of the axial opening 213 along the C direction.
[0130] Either the first part 2121 or the second part 2122 has a larger dimension along direction B to ensure the structural strength of the radial protrusion 212 and improve its ability to resist circumferential tangential forces during motor operation. The axial opening 213 has a smaller dimension along direction C to act as a buffer, solving the problem of… Figure 4 The problem of high extrusion stress between the stator housing 4 and the stator core 21.
[0131] In some embodiments, refer to Figure 8 and Figure 11 The radial protrusion 212 also includes a third part 2123, which and the annular part 211 are distributed along the C direction on both sides of the axial opening 213. The third part 2123 is distributed along the C direction on one side of the axial opening 213, and the annular part 211 is distributed on the other side of the axial opening 213.
[0132] The dimension of the third part 2123 along the C direction is smaller than the dimension of the axial opening 213 along the C direction, so that the third part 2123 can produce controllable elastic deformation to absorb and disperse the stator core 21 and Figure 4 The local assembly stress during the press-fitting process of the stator housing 4.
[0133] In some embodiments, the dimension of the third portion 2123 along the C direction is 2 ± 0.03 mm.
[0134] In some embodiments, refer to Figure 8 and Figure 11 The dimension of the third part 2123 along the C direction is smaller than the dimension of either the first part 2121 or the second part 2122 along the B direction. This ensures that the third part 2123 produces controllable elastic deformation to absorb and disperse the stator core 21 and... Figure 4 The local assembly compressive stress during the press-fitting process of the stator housing 4 in the middle, on the other hand, ensures the structural strength of the radial protrusion 212 and improves the ability of the radial protrusion 212 to resist the circumferential tangential force during the operation of the drive motor.
[0135] In some embodiments, refer to Figure 8 and Figure 11 The dimension of the third part 2123 along the C direction is smaller than the dimension of either the first part 2121 or the second part 2122 along the C direction, so as to ensure that the third part 2123 produces controllable elastic deformation and reduce the impact of compressive stress on motor performance during stator core 21 assembly.
[0136] In addition to the above, in practical applications, those skilled in the art can also design the size and shape of the axial opening 213 according to actual needs, so that the width, length, and other dimensions of the axial opening 213 have a corresponding matching relationship with the width, length, and other dimensions of the radial protrusion 212. On the one hand, this allows the radial protrusion 212 to undergo controllable elastic deformation, effectively absorbing and dispersing the local assembly stress between the stator housing 4 and the stator core 21. On the other hand, it minimizes the disruption to the magnetic circuit symmetry of the stator core 21, thereby ensuring the uniformity of the magnetic circuit in the stator core 21.
[0137] In some embodiments, the axial opening 213 has a dimension of 36 mm along the B direction. The radial protrusion 212 has a dimension of 50 ± 0.03 mm along the B direction.
[0138] To further reduce the compressive stress transmitted to the annular portion 211 of the stator core 21 during the assembly process of the stator core 21 and the stator housing 4, in some embodiments, refer to... Figure 5 One end of the radial protrusion 212 along the B direction is at an angle to the tangent direction of the outer periphery of the annular portion 211, or one end of the radial protrusion 212 along the B direction is arc-shaped.
[0139] When the radial protrusion 212 is embedded in the groove 41, the tilt angle or arc-shaped area of the end face of the radial protrusion causes the radial protrusion 212 to produce controllable elastic deformation, thereby further reducing the compressive stress between the stator core 21 and the stator housing during the assembly process.
[0140] In some embodiments, the angle α between one end of the radial protrusion 212 along the B direction and the tangential direction of the outer periphery of the annular portion 211 is 0.24°.
[0141] Based on the above, the drive motor 10 provided in this application solves, on the one hand, the problem of large compressive stress between the stator housing 4 and the stator core 21 during the assembly process; on the other hand, it solves the problems of precise positioning during the assembly process of the stator housing 4 and the stator core 21, and resists the load and vibration caused by the alternating component of the tangential magnetic pull during the operation of the drive motor 10. It also solves the problem of magnetic circuit asymmetry within the stator core 21 caused by the addition of the radial protrusion 212.
[0142] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. A drive motor, characterized in that, The drive motor is used to drive an electric vehicle. The drive motor includes a stator housing and a stator core. The stator housing is used to accommodate and fix the stator core. The stator core includes: Ring-shaped part; Multiple radial protrusions, each radial protrusion protruding along the radial direction of the drive motor, each radial protrusion fixedly connected to the outer periphery of the annular portion, the multiple radial protrusions being distributed at intervals along the circumference of the drive motor, each radial protrusion being used to embed into a groove on the inner periphery of the stator housing; Multiple axial openings, each of the axial openings being distributed in at least one of the radial protrusions and the annular portion.
2. The drive motor according to claim 1, characterized in that, The cross-sectional shape of the radial protrusion has a radial dimension smaller than the circumferential dimension of the drive motor.
3. The drive motor according to any one of claims 1-2, characterized in that, The size of the radial protrusion along the circumference of the drive motor is smaller than the distance between two adjacent radial protrusions.
4. The drive motor according to any one of claims 1-3, characterized in that, The cross-sectional shape of the axial opening has a radial dimension smaller than the circumferential dimension of the drive motor.
5. The drive motor according to any one of claims 1-4, characterized in that, A portion of the axial opening is formed on the outer peripheral surface of the annular portion, and another portion of the axial opening is formed on the radial protrusion.
6. The drive motor according to any one of claims 1-5, characterized in that, The area of the axial opening located in the cross-section of the annular portion is different from the area of the axial opening located in the cross-section of the radial protrusion.
7. The drive motor according to any one of claims 1-6, characterized in that, The shape of the cross-section of the axial opening located on the annular portion is different from the shape of the cross-section of the axial opening located on the radial protrusion.
8. The drive motor according to any one of claims 1-7, characterized in that, The cross-sectional shape of the axial opening located on the annular portion along the radial direction of the drive motor is different from the cross-sectional shape of the axial opening located on the radial protrusion along the radial direction of the drive motor.
9. The drive motor according to any one of claims 1-8, characterized in that, The axial opening includes a first section of hole wall and a second section of hole wall. The first section of hole wall and the second section of hole wall are distributed relative to each other along the radial direction of the drive motor. The distance between the first section of hole wall and the central axis of the drive motor is greater than the distance between the second section of hole wall and the central axis of the drive motor. The cross-sectional shape of the first section of hole wall is U-shaped, and the cross-sectional shape of the second section of hole wall is arc-shaped.
10. The drive motor according to any one of claims 1-9, characterized in that, The radial protrusion includes a first part and a second part, which are distributed on both sides of the axial opening along the circumference of the drive motor. The dimension of either the first part or the second part along the circumference of the drive motor is greater than the dimension of the axial opening along the radial direction of the drive motor.
11. The drive motor according to claim 10, characterized in that, The radial protrusion further includes a third part, which, along with the annular part, is distributed on both sides of the axial opening along the radial direction of the drive motor. The dimension of the third part along the radial direction of the drive motor is smaller than the dimension of the axial opening along the radial direction of the drive motor.
12. The drive motor according to claim 11, characterized in that, The third part has a radial dimension smaller than either the first part or the second part, which has a circumferential dimension smaller than that of the drive motor.
13. The drive motor according to claim 11 or 12, characterized in that, The dimension of the third part along the radial direction of the drive motor is smaller than the dimension of either the first part or the second part along the radial direction of the drive motor.
14. A powertrain, characterized in that, The powertrain includes a reducer and a drive motor according to any one of claims 1-13, the drive motor being used to drive the wheels of the electric vehicle via the reducer.
15. An electric vehicle, characterized in that, The electric vehicle includes wheels and the powertrain of claim 14, the powertrain being used to drive the wheels.