Electric power steering motor, electric power steering system and vehicle

Abstract

The utility model provides an electric power steering motor, an electric power steering system and a vehicle. The electric power-assisted steering motor comprises a stator iron core, a rotor and a rotor, the rotor iron core comprises a plurality of iron core sections, the plurality of iron core sections are superposed, and the rotor iron core is provided with a shaft hole; a first bearing; the first bearing and the second bearing are both arranged on the rotating shaft in a sleeving mode, the rotor iron core is located between the first bearing and the second bearing, and at least one of the first bearing and the second bearing is a four-point contact ball bearing; the axial clearance delta of the four-point contact ball bearing, the minimum value lg of the gap between the cavity wall of the accommodating cavity and the peripheral wall of the rotor iron core, the inner diameter R1 of the stator iron core, the outer diameter R2 of the stator iron core, the axial length Ls of the stator iron core and the axial length Lr of the rotor iron core meet delta * (Lr + Ls) lt; and 2 * 1g * (R2-R1). According to the arrangement, the overall deformation resistance of the motor can be enhanced, and the structural rigidity of the electric power steering motor can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of motors, and in particular, to an electric power steering motor, an electric power steering system, and a vehicle. Background Art

[0002] In the related art, the motor of a new energy vehicle includes a stator core, a rotor core, a first bearing, and a second bearing. The structural settings of the stator core, the rotor core, the first bearing, and the second bearing are unreasonable, and the vibration and noise of the motor are relatively large, resulting in a relatively large noise during vehicle driving, which seriously affects the driving experience of users. Summary of the Utility Model

[0003] The present application aims to solve at least one of the technical problems existing in the prior art or related art.

[0004] To this end, a first aspect of the present application provides an electric power steering motor.

[0005] A second aspect of the present application provides an electric power steering system.

[0006] A third aspect of the present application provides a vehicle.

[0007] In view of this, the present application provides an electric power steering motor, including: a stator core provided with a receiving cavity; a rotor core disposed in the receiving cavity, the rotor core including a plurality of core segments stacked, any two adjacent core segments being arranged offset in the clockwise direction or in the counterclockwise direction, the rotor core being provided with a shaft hole axially penetrating through the plurality of core segments along the axial direction of the rotor core; a rotating shaft passing through the shaft hole; a first bearing; a second bearing, both the first bearing and the second bearing being sleeved on the rotating shaft, the rotor core being located between the first bearing and the second bearing, and at least one of the first bearing and the second bearing being a four-point contact ball bearing; the axial clearance δ of the four-point contact ball bearing, the minimum clearance value lg between the cavity wall of the receiving cavity and the outer peripheral wall of the rotor core, the inner diameter R1 of the stator core, the outer diameter R2 of the stator core, the axial length Ls of the stator core, and the axial length Lr of the rotor core satisfy: δ×(Lr + Ls) < 2×lg×(R2 - R1).

[0008] An electric power steering motor provided by the present application includes a stator core, a rotor core, a rotating shaft, a first bearing, and a second bearing.

[0009] The rotor core includes a plurality of core segments stacked along the axial direction of the rotor core. Among them, any two adjacent core segments are arranged offset in the clockwise direction, or any two adjacent core segments are arranged offset in the counterclockwise direction. That is, any two adjacent core segments are arranged offset in the circumferential direction of the rotor core to form a rotor skewed pole. The segmented modular setting of the rotor core has the advantages of being convenient for installation and maintenance, and an inclined pole can be formed between the plurality of core segments.

[0010] It is defined that any two adjacent iron core segments are arranged staggeredly in the clockwise or counterclockwise direction, which can reduce the cogging torque and torque ripple, thereby reducing the electromagnetic vibration. That is to say, by dividing the rotor iron core into multiple iron core segments and arranging any two adjacent iron core segments staggeredly in the clockwise or counterclockwise direction, the specific harmonic content in the electric power steering motor can be effectively suppressed, the torque ripple and cogging torque of the electric power steering motor can be improved, and thus the vibration and noise of the electric power steering motor can be reduced.

[0011] Furthermore, the rotor iron core is provided with a shaft hole, the shaft hole axially penetrates through multiple iron core segments along the rotor iron core, a rotating shaft is inserted into the shaft hole, a first bearing is sleeved on the rotating shaft, a second bearing is sleeved on the rotating shaft, the first bearing is located outside the rotor iron core, and the second bearing is located outside the rotor iron core. Among them, the rotor iron core is located between the first bearing and the second bearing.

[0012] At least one of the first bearing and the second bearing is a four-point contact ball bearing. That is, the first bearing is a four-point contact ball bearing. Or, the second bearing is a four-point contact ball bearing. Or the first bearing is a four-point contact ball bearing and the second bearing is a four-point contact ball bearing.

[0013] The four-point contact ball bearing can enhance the overall anti-deformation ability of the electric power steering motor, is beneficial to improving the structural stiffness of the electric power steering motor, can reduce the axial end play when the electric power steering motor works. In this way, the vibration performance of the electric power steering motor during operation is further improved, the vibration and noise of the electric power steering motor can be further reduced, and the service performance and market competitiveness of the electric power steering motor are greatly improved.

[0014] Furthermore, the axial clearance of the four-point contact ball bearing is denoted as δ, the minimum value of the clearance between the cavity wall of the accommodating cavity and the outer peripheral wall of the rotor iron core is denoted as lg, the inner diameter of the stator iron core is denoted as R1, the outer diameter of the stator iron core is denoted as R2, and the axial length of the stator iron core is denoted as Ls, the axial length of the rotor iron core is denoted as Lr. Among them, δ, lg, R1, R2, Ls and Lr satisfy: δ×(Lr + Ls) < 2×lg×(R2 - R1). That is to say, the clearance of the four-point contact ball bearing and the matching structure of the stator iron core and the rotor iron core are defined. This setting can enhance the overall anti-deformation ability of the electric power steering motor, is beneficial to improving the structural stiffness of the electric power steering motor, can reduce the axial end play when the electric power steering motor works. In this way, the vibration performance of the electric power steering motor during operation is further improved, the vibration and noise of the motor can be further reduced, and the service performance and market competitiveness of the motor are greatly improved.

[0015] It can be understood that when there is no load, the inner ring of the four-point contact ball bearing is fixed, and the displacement of the outer ring of the four-point contact ball bearing relative to the fixed inner ring along the axial direction of the rotor core from one extreme position to another extreme position is denoted as the axial clearance of the four-point contact ball bearing. Or, when there is no load, the outer ring of the four-point contact ball bearing is fixed, and the displacement of the inner ring of the four-point contact ball bearing relative to the fixed outer ring along the axial direction of the rotor core from one extreme position to another extreme position is denoted as the axial clearance of the four-point contact ball bearing.

[0016] When both the first bearing and the second bearing are four-point contact ball bearings, that is, four-point contact ball bearings are arranged on both axial sides of the rotor core. In this way, the mating area and mating angle between the first bearing, the second bearing and the rotating shaft are increased, which can further enhance the overall anti-deformation ability of the rotor, can further improve the structural stiffness of the electric power steering motor, can reduce the axial movement amount during the operation of the electric power steering motor. In this way, the vibration performance during the operation of the electric power steering motor is further improved, and the vibration noise of the electric power steering motor can be further reduced.

[0017] According to the above-mentioned electric power steering motor of the present application, the following additional technical features may also be provided:

[0018] In some embodiments, optionally, δ, lg, R1, R2, Ls and Lr satisfy: 0 < (δ × (Lr + Ls)) / (2 × lg × (R2 - R1)) ≤ 0.8.

[0019] In this embodiment, the mating structure of the axial clearance δ of the four-point contact ball bearing, the minimum clearance lg between the wall of the accommodating cavity and the outer peripheral wall of the rotor core, the inner diameter R1 of the stator core, the outer diameter R2 of the stator core, the axial length Ls of the stator core and the axial length Lr of the rotor core is further defined.

[0020] Specifically, δ, lg, R1, R2, Ls and Lr satisfy: 0 < (δ × (Lr + Ls)) / (2 × lg × (R2 - R1)) ≤ 0.8. To enhance the overall anti-deformation ability of the electric power steering motor, it is beneficial to improve the structural stiffness of the electric power steering motor, can reduce the axial movement amount during the operation of the electric power steering motor. In this way, the vibration performance during the operation of the electric power steering motor is further improved, and the vibration noise of the motor can be further reduced, greatly improving the use performance and market competitiveness of the motor.

[0021] In some embodiments, optionally, the electric power steering motor further includes: a housing having a first bearing cavity and a second bearing cavity therein, a stator core, a rotor core, a rotating shaft, a first bearing, and a second bearing are all disposed in the housing, the first bearing is located in the first bearing cavity, and the second bearing is located in the second bearing cavity; a first elastic part disposed in the first bearing cavity, the first elastic part abuts between a side of the first bearing facing away from the rotor core and the cavity wall of the first bearing cavity, and the first elastic part is configured to apply an axial preloading force to the first bearing; wherein, the first bearing is in interference fit with the rotating shaft.

[0022] In this embodiment, the electric power steering motor further includes a housing and a first elastic part.

[0023] The stator core, the rotor core, the rotating shaft, the first bearing, and the second bearing are all disposed in the housing. That is to say, the housing serves as an installation carrier for the stator core, the rotor core, the rotating shaft, the first bearing, and the second bearing, and has the function of installing and fixing the stator core, the rotor core, the rotating shaft, the first bearing, and the second bearing to ensure the mating dimensions of the stator core, the rotor core, the rotating shaft, the first bearing, and the second bearing.

[0024] The housing has a first bearing cavity and a second bearing cavity therein. The first bearing cavity is used for installing the first bearing, and the second bearing cavity is used for installing the second bearing.

[0025] The first bearing is in interference fit with the rotating shaft. The first elastic part is disposed in the first bearing cavity. The first bearing is located between the first elastic part and the rotor core. The first elastic part abuts against the first bearing, and the first elastic part abuts against the cavity wall of the first bearing cavity. That is to say, the first elastic part abuts between a side of the first bearing facing away from the rotor core and the cavity wall of the first bearing cavity. The first elastic part is used to apply an axial preloading force to the first bearing so that the first bearing is stably assembled on the rotating shaft.

[0026] It can be understood that after the electric power steering motor is assembled, the first elastic part is located between the first bearing and the cavity wall of the first bearing cavity. By squeezing the first elastic part, the first elastic part applies an axial preloading force to the first bearing to ensure the structural stiffness of the electric power steering motor and is beneficial to reducing the axial runout amount when the electric power steering motor is working.

[0027] It can be understood that the cavity wall of the first bearing cavity has the function of limiting the first bearing. Specifically, the cavity wall of the first bearing cavity is used to radially limit the first bearing on the rotating shaft.

[0028] In addition, the first bearing is in interference fit with the rotating shaft to axially and radially limit the first bearing on the rotating shaft.

[0029] Optionally, the first elastic part includes a wave washer, a spring, a torsion spring, a tension spring, etc., which are not listed one by one here.

[0030] In some embodiments, optionally, a fixing protrusion is provided in the second bearing cavity, the fixing protrusion abuts against the outer peripheral wall of the second bearing, and the second bearing is in interference fit with the rotating shaft.

[0031] In this embodiment, the mating structure between the housing and the second bearing is further defined.

[0032] Specifically, a fixing protrusion is provided in the second bearing cavity, the fixing protrusion abuts against the outer peripheral wall of the second bearing. Specifically, the fixing protrusion is riveted to the outside of the second bearing, and the second bearing is in interference fit with the rotating shaft. The fixing protrusion and the rotating shaft cooperate to limit the second bearing axially, radially, and circumferentially along the rotating shaft. To improve the structural stiffness of the electric power steering motor, the axial runout during the operation of the electric power steering motor can be reduced, and the overall anti-deformation ability of the electric power steering motor can be enhanced. In this way, the vibration performance during the operation of the electric power steering motor is further improved, the vibration noise of the electric power steering motor can be further reduced, and the service performance and market competitiveness of the electric power steering motor are greatly improved.

[0033] In some embodiments, optionally, when one of the first bearing and the second bearing is a four-point contact ball bearing, the second bearing is a four-point contact ball bearing.

[0034] In this embodiment, the types of the first bearing and the second bearing are further defined.

[0035] Specifically, when one of the first bearing and the second bearing is a four-point contact ball bearing, the second bearing is a four-point contact ball bearing, and the first bearing is a non-four-point contact ball bearing.

[0036] In some embodiments, optionally, the axial clearance of the second bearing is less than or equal to 0.1 mm.

[0037] In this embodiment, the value range of the axial clearance δ of the second bearing is further defined such that δ ≤ 0.1 mm. In this way, the axial vibration of the electric power steering motor can be further optimized to further optimize the vibration noise of the electric power steering motor.

[0038] In some embodiments, optionally, along the axial direction of the rotating shaft, the minimum distance between the end faces of the second bearing and the rotor core close to each other is d; wherein, 0.025 ≤ (2 × d) / (Lr + Ls) ≤ 1.25.

[0039] In this embodiment, the mating structure between the second bearing and the rotor core is further defined.

[0040] Axially along the rotating shaft, the minimum distance between the second bearing and the end face of the rotor core close to each other is d. That is, axially along the rotating shaft, the end face of the second bearing facing the rotor core is the first end face, and the end face of the rotor core facing the second bearing is the second end face. The minimum distance between the first end face and the second end face is d.

[0041] Among them, d, Lr, and Ls satisfy 0.025 ≤ (2×d) / (Lr + Ls) ≤ 1.25. The smaller the distance d, the greater the axial force on the second bearing affected by the leakage magnetic field. The larger the distance d, the higher the production cost will be. That is to say, d, Lr, and Ls satisfy 0.025 ≤ (2×d) / (Lr + Ls) ≤ 1.25, taking into account both the axial force on the second bearing and the production cost of the product. The cost of the product is controlled within a reasonable range, and the axial force on the second bearing is relatively optimal, with the highest cost performance.

[0042] In some embodiments, optionally, a first card slot is further provided in the housing. The first card slot is located on the side of the second bearing cavity facing the first bearing cavity, and the first card slot communicates with the second bearing cavity; the electric power steering motor further includes a second elastic part. The second elastic part is disposed in the first card slot, the second elastic part is arranged around the rotating shaft, and the second elastic part abuts against the second bearing. The second elastic part is used to limit the axial displacement of the second bearing, and the second bearing is in interference fit with the rotating shaft.

[0043] In this embodiment, the mating structure of the rotating shaft and the second bearing is further defined.

[0044] A first card slot is further provided in the housing. The first card slot is located on the side of the second bearing cavity facing the first bearing cavity, and the first card slot communicates with the second bearing cavity.

[0045] The electric power steering motor further includes a second elastic part. The first card slot is used for installing and fixing the second elastic part. The second elastic part is disposed in the first card slot, the second elastic part is arranged around the rotating shaft, and the second elastic part abuts against the second bearing. The second elastic part is used to axially limit the second bearing along the rotating shaft to ensure the mating dimensions of the second bearing and the rotating shaft. It is beneficial to improve the stability and reliability of the assembly of the rotating shaft and the second bearing, enhance the overall anti-deformation ability of the electric power steering motor, and reduce the frictional torque of the electric power steering motor.

[0046] The second bearing is in interference fit with the rotating shaft. The rotating shaft and the second elastic part cooperate to stably assemble the second bearing and the rotating shaft together.

[0047] The rotating shaft and the second elastic part cooperate to limit the second bearing axially, radially and circumferentially along the rotating shaft. This improves the structural stiffness of the electric power steering motor, reduces the axial runout of the electric power steering motor during operation, and enhances the overall anti-deformation ability of the electric power steering motor. In this way, the vibration performance of the electric power steering motor during operation is further improved, the vibration noise of the electric power steering motor can be further reduced, and the service performance and market competitiveness of the electric power steering motor are greatly improved.

[0048] In addition, the second bearing is a four-point contact ball bearing, the second bearing is in interference fit with the rotating shaft, and the second elastic part restricts the axial displacement of the second bearing. This setting can reduce the influence on the radial clearance of the second bearing and ensure the radial clearance of the second bearing. In this way, it is beneficial to reduce the frictional torque of the electric power steering motor during operation. That is to say, this setting takes into account reducing the vibration noise of the electric power steering motor and reducing the frictional torque of the electric power steering motor, improving the service performance and market competitiveness of the product.

[0049] Optionally, the second elastic part includes springs, torsion springs, tension springs, etc., which are not listed one by one here.

[0050] It can be understood that when there is no load, the inner ring of the second bearing is fixed, and the displacement of the outer ring of the second bearing relative to the fixed inner ring from one extreme position to another extreme position along the radial direction of the rotor core is denoted as the radial clearance of the second bearing.

[0051] In some embodiments, optionally, the end face of the second bearing facing the rotor core is connected to the outer peripheral wall of the rotating shaft through a welding fixing part, and the second bearing is in clearance fit with the rotating shaft.

[0052] In this embodiment, the fitting structure of the rotating shaft and the second bearing is further defined.

[0053] Specifically, the second bearing is in clearance fit with the rotating shaft, and the end face of the second bearing facing the rotor core is connected to the outer peripheral wall of the rotating shaft through a welding fixing part. That is to say, the welding fixing part firmly assembles the second bearing and the rotating shaft together.

[0054] The welding fixing part and the rotating shaft cooperate to limit the second bearing axially, radially and circumferentially along the rotating shaft. This improves the structural stiffness of the electric power steering motor, reduces the axial runout of the electric power steering motor during operation, and enhances the overall anti-deformation ability of the electric power steering motor. In this way, the vibration performance of the electric power steering motor during operation is further improved, the vibration noise of the electric power steering motor can be further reduced, and the service performance and market competitiveness of the electric power steering motor are greatly improved.

[0055] In addition, the second bearing is a four-point contact ball bearing, and the second bearing and the rotating shaft are stably assembled through the welding fixing part. This setting can reduce the influence on the radial clearance of the second bearing, ensure the radial clearance of the second bearing, and thus is beneficial to reducing the frictional torque during the operation of the electric power steering motor. That is to say, this setting takes into account reducing the vibration and noise of the electric power steering motor and reducing the frictional torque of the electric power steering motor, improving the service performance and market competitiveness of the product.

[0056] It can be understood that when there is no load, the inner ring of the second bearing is fixed, and the displacement of the outer ring of the second bearing relative to the fixed inner ring from one extreme position to another extreme position along the radial direction of the rotor core is denoted as the radial clearance of the second bearing.

[0057] In some embodiments, optionally, a second clamping groove is further provided in the housing. The second clamping groove is located on the side of the second bearing cavity facing the first bearing cavity, and the second clamping groove communicates with the second bearing cavity; the electric power steering motor further includes a third elastic part. The third elastic part is arranged in the second clamping groove, the third elastic part surrounds the rotating shaft, and the third elastic part abuts against the second bearing. The third elastic part is used to limit the axial displacement of the second bearing.

[0058] In this embodiment, the matching structure between the housing and the second bearing is further defined.

[0059] A second clamping groove is further provided in the housing. The second clamping groove is located on the side of the second bearing cavity facing the first bearing cavity, and the second clamping groove communicates with the second bearing cavity.

[0060] The electric power steering motor further includes a third elastic part. The second clamping groove is used for installing and fixing the third elastic part. The third elastic part is arranged in the second clamping groove, the third elastic part surrounds the rotating shaft, and the third elastic part abuts against the second bearing. The third elastic part is used to axially limit the second bearing along the rotating shaft to ensure the matching dimensions of the second bearing and the rotating shaft. It is beneficial to improve the stability and reliability of the assembly of the rotating shaft and the second bearing, enhance the overall anti-deformation ability of the electric power steering motor, and reduce the frictional torque of the electric power steering motor.

[0061] The welding fixing part and the third elastic part cooperate to ensure the radial clearance of the second bearing while reducing the vibration and noise of the electric power steering motor, enhance the anti-deformation ability of the electric power steering motor, and reduce the frictional torque of the electric power steering motor. That is to say, this setting takes into account reducing the vibration and noise of the electric power steering motor and reducing the frictional torque of the electric power steering motor, improving the service performance and market competitiveness of the product.

[0062] In some embodiments, optionally, each iron core segment includes a plurality of rotor punching sheets which are stacked, and the stator iron core includes a plurality of stator punching sheets which are stacked; among any two adjacent rotor punching sheets, one rotor punching sheet is provided with a first convex portion, and the other rotor punching sheet is provided with a first groove, and the first convex portion and the first groove are in interference fit; among any two adjacent stator punching sheets, one stator punching sheet is provided with a second convex portion, and the other stator punching sheet is provided with a second groove, and the second convex portion and the second groove are in interference fit.

[0063] In this embodiment, each iron core segment includes a plurality of rotor punching sheets which are stacked.

[0064] Among any two adjacent rotor punching sheets, one rotor punching sheet is provided with a first convex portion, and the other rotor punching sheet is provided with a first groove, and the first convex portion and the first groove are in interference fit.

[0065] Specifically, a first groove is provided on the axial end face of the first side of each rotor punching sheet, and a first convex portion is provided on the axial end face of the second side of each rotor punching sheet. That is, along the axial direction of the rotor iron core, the rotor punching sheet has a first end face and a second end face which are oppositely arranged, the first end face is provided with a first groove, and the second end face is provided with a first convex portion.

[0066] When two adjacent rotor punching sheets are assembled, the first convex portion is inserted into the first groove, and the first convex portion and the first groove are in interference fit to achieve the purpose of assembling the two rotor punching sheets.

[0067] The first convex portion and the first groove cooperate to increase the contact area and contact angle between two adjacent rotor punching sheets, which is beneficial to improving the stability and reliability of the assembly of two adjacent rotor punching sheets in the axial direction of the rotor iron core, preventing the rotor punching sheets from being scattered, and ensuring the structural stiffness of the rotor iron core assembly.

[0068] In this embodiment, the stator iron core includes a plurality of stator punching sheets which are stacked.

[0069] Among any two adjacent stator punching sheets, one stator punching sheet is provided with a second convex portion, and the other stator punching sheet is provided with a second groove, and the second convex portion and the second groove are in interference fit.

[0070] Specifically, a second groove is provided on the axial end face of the first side of each stator punching sheet, and a second convex portion is provided on the axial end face of the second side of each stator punching sheet. That is, along the axial direction of the stator iron core, the stator punching sheet has a first end face and a second end face which are oppositely arranged, the first end face is provided with a second groove, and the second end face is provided with a second convex portion.

[0071] When two adjacent stator punching sheets are assembled, the second convex portion is inserted into the second groove, and the second convex portion and the second groove are in interference fit to achieve the purpose of assembling the two stator punching sheets.

[0072] The second convex part and the second groove cooperate to increase the contact area and contact angle between two adjacent stator laminations, which is beneficial to improving the stability and reliability of the axial assembly of two adjacent stator laminations in the stator core, preventing the stator laminations from becoming loose, and ensuring the structural stiffness of the stator core assembly.

[0073] In some embodiments, optionally, the stator core includes a plurality of stator core blocks that are sequentially connected end to end around the axis of the shaft hole; the centers of the circumferences corresponding to the outer circumferential walls of the stator core blocks coincide with the centers of the circumferences corresponding to the inner circumferential walls of the stator core blocks.

[0074] In this embodiment, the stator core includes a plurality of stator core blocks that are sequentially connected end to end around the axis of the shaft hole.

[0075] Among them, the centers of the circumferences corresponding to the outer circumferential walls of the stator core blocks coincide with the centers of the circumferences corresponding to the inner circumferential walls of the stator core blocks.

[0076] That is to say, the stator core has a structure of a segmented core, and a plurality of stator core blocks are sequentially connected end to end around the axis of the shaft hole. This setting can greatly improve the slot fill factor of the electric power steering motor, further improve the power density of the electric power steering motor, and ensure that the product performance requirements are met without using heavy rare earth elements.

[0077] In some embodiments, optionally, the rotor core is further provided with a plurality of magnet slots that are arranged at intervals along the circumferential direction of the rotating shaft, and the magnet slots are located between the shaft hole and the outer circumferential wall of the rotor core; the electric power steering motor further includes a plurality of permanent magnets, and each permanent magnet is arranged in one magnet slot.

[0078] In this embodiment, the specific structure of the electric power steering motor is further defined.

[0079] The part of the rotor core located between the shaft hole and the outer circumferential wall of the rotor core is provided with a plurality of magnet slots that are arranged at intervals along the circumferential direction of the rotating shaft.

[0080] The electric power steering motor further includes a plurality of permanent magnets, and each permanent magnet is arranged in one magnet slot. That is to say, a plurality of permanent magnets are arranged on the rotor core, and the plurality of permanent magnets are arranged at intervals along the circumferential direction of the rotating shaft. The permanent magnets are located between the shaft hole and the outer circumferential wall of the rotor core.

[0081] In some embodiments, optionally, the rotor core is further provided with a plurality of weight reduction holes that are arranged at intervals along the circumferential direction of the rotating shaft, the weight reduction holes are located between the rotating shaft and the permanent magnets; the number of weight reduction holes is greater than or equal to the number of pole pairs of the electric power steering motor.

[0082] In this embodiment, the structure of the rotor core is further defined such that the rotor core is provided with a plurality of weight-reducing holes which are arranged at intervals in the circumferential direction around the rotating shaft, and the weight-reducing holes are located between the rotating shaft and the permanent magnets. The weight-reducing holes serve to reduce the overall weight of the electric power steering motor.

[0083] In addition, any two adjacent core segments are arranged staggeredly in the clockwise or counterclockwise direction, that is, any two adjacent core segments are arranged staggeredly in the circumferential direction of the rotor core to form a skewed pole of the rotor. The weight-reducing holes can be used as a positioning basis for assembling the rotor core, providing a reliable structural support for ensuring the formation of the skewed pole of the rotor.

[0084] Furthermore, the number of the weight-reducing holes is greater than or equal to the number of pole pairs of the electric power steering motor, and the plurality of weight-reducing holes are arranged at intervals in the circumferential direction around the rotating shaft. In this way, when assembling the rotor core, the plurality of core segments can be positioned from multiple directions and angles, ensuring the fitting accuracy of the plurality of core segments.

[0085] In some embodiments, optionally, at least a part of the hole wall of the shaft hole is in interference fit with the rotating shaft.

[0086] In this embodiment, the fitting structure between the rotor core and the rotating shaft is defined.

[0087] At least a part of the hole wall of the shaft hole is in interference fit with the rotating shaft. That is, a part of the hole wall of the shaft hole is in interference fit with the rotating shaft. Or the entire hole wall of the shaft hole is in interference fit with the rotating shaft.

[0088] This setting can ensure the fitting structure between the rotating shaft and the rotor core, avoiding the separation of the rotating shaft and the rotor core.

[0089] When a part of the hole wall of the shaft hole is in interference fit with the rotating shaft, the contact area between the shaft hole and the rotating shaft can be reduced. That is, while ensuring the use requirement of the interference fit between the rotating shaft and the shaft hole, the radial force formed by the interference fit between the shaft hole and the rotating shaft can be reduced due to the reduction of the contact area between the shaft hole and the rotating shaft, which can reduce the influence of the radial force on the bonding force between the rotor laminations of the rotor core, being beneficial to reducing the probability of deformation of the rotor laminations of the rotor core and further reducing the probability of loosening of the plurality of rotor laminations of the rotor core.

[0090] Optionally, the hole wall of the shaft hole is a convex-concave wall, the protrusions of the convex-concave wall are in interference fit with the rotating shaft, and the depressions of the convex-concave wall are arranged separately from the rotating shaft. The protrusions and depressions of the convex-concave wall are arranged staggeredly, and both the protrusions and the depressions extend along the axial direction of the rotating shaft.

[0091] A second aspect of the present utility model proposes an electric power steering system, comprising: the electric power steering motor as in the first aspect.

[0092] The electric power steering system provided by the present utility model includes an electric power steering motor as in the first aspect. Therefore, it has all the beneficial effects of the above-mentioned electric power steering motor, and will not be elaborated one by one here.

[0093] A third aspect of the present utility model provides a vehicle, comprising: an electric power steering motor as in the first aspect; or an electric power steering system as in the second aspect.

[0094] The vehicle provided by the present utility model includes an electric power steering motor as in the first aspect, or includes an electric power steering system as in the second aspect. Therefore, it has all the beneficial effects of the above-mentioned electric power steering motor or electric power steering system, and will not be elaborated one by one here.

[0095] It should be noted that the vehicle can be a new energy vehicle. New energy vehicles include pure electric vehicles, range-extended electric vehicles, hybrid vehicles, fuel cell electric vehicles, hydrogen engine vehicles, etc.

[0096] The vehicle can also be a fuel vehicle.

[0097] The additional aspects and advantages of the present application will become apparent in the following description section, or be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0098] The above and / or additional aspects and advantages of the present application will become apparent and be readily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0099] Figure 1 FIG. 1 shows a schematic diagram of the first part of the structure of an electric power steering motor according to an embodiment of the present application;

[0100] Figure 2 FIG. 2 shows an exploded view of the first part of an electric power steering motor according to an embodiment of the present application;

[0101] Figure 3 FIG. 3 shows an exploded view of the second part of an electric power steering motor according to an embodiment of the present application;

[0102] Figure 4 FIG. 4 shows an exploded view of the third part of an electric power steering motor according to an embodiment of the present application;

[0103] Figure 5 FIG. 5 shows an exploded view of the fourth part of an electric power steering motor according to an embodiment of the present application;

[0104] Figure 6 FIG. 6 shows a schematic diagram of the structure of an electric power steering motor according to the first embodiment of the present application;

[0105] Figure 7 Shows a partial structural schematic diagram of an electric power steering motor according to the first embodiment of the present application;

[0106] Figure 8 Shows a partial structural schematic diagram of an electric power steering motor according to the second embodiment of the present application;

[0107] Figure 9 Shows a partial structural schematic diagram of an electric power steering motor according to the third embodiment of the present application;

[0108] Figure 10 Shows a partial structural schematic diagram of a stator core according to an embodiment of the present application;

[0109] Figure 11 Shows a partial structural schematic diagram of a rotor core according to an embodiment of the present application;

[0110] Figure 12 Shows a structural schematic diagram of a second bearing according to an embodiment of the present application;

[0111] Figure 13 Shows a data graph of the ratio of the 24th-order noise of the motor according to the present application to the motor in the related art changing with the change of X;

[0112] Figure 14 Shows a data graph of the axial force and cost received by the second bearing according to the present application changing with the change of V.

[0113] Among them, Figures 1 to 14 The corresponding relationship between the reference numerals and component names in

[0114] 10 Electric power steering motor, 100 Stator core, 110 Accommodation cavity, 120 Stator punching, 130 Second convex portion, 140 Second groove, 150 Stator core block, 152 Outer peripheral wall of the stator core block, 154 Inner peripheral wall of the stator core block, 200 Rotor core, 210 Core segment, 212 Rotor punching, 220 Shaft hole, 230 First convex portion, 240 First groove, 250 Magnet slot, 260 Weight reduction hole, 300 Rotating shaft, 400 First bearing, 500 Second bearing, 600 Housing, 610 First bearing cavity, 620 Second bearing cavity, 622 Fixed protrusion, 630 First card slot, 640 Second card slot, 650 Machine shell, 660 End cover, 700 First elastic portion, 800 Second elastic portion, 900 Permanent magnet, 1000 Third elastic portion, 1100 Welding fixing portion. Detailed implementation manners

[0115] In order to more clearly understand the above-mentioned objects, features, and advantages of the present application, the present application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that, without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other.

[0116] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application. However, the present application may be implemented in other ways different from those described herein. Therefore, the scope of protection of the present application is not limited by the specific embodiments disclosed below.

[0117] The following refers to Figures 1 to 14 Describe an electric power steering motor 10, an electric power steering system, and a vehicle according to some embodiments of the present application.

[0118] As Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 And Figure 12 As shown in

[0119] The stator core 100 is provided with a receiving cavity 110.

[0120] The rotor core 200 is disposed in the receiving cavity 110.

[0121] The rotor core 200 includes a plurality of core segments 210.

[0122] The plurality of core segments 210 are stacked.

[0123] Any two adjacent core segments 210 are arranged staggeredly in the clockwise direction or the counterclockwise direction.

[0124] The rotor core 200 is provided with a shaft hole 220.

[0125] The shaft hole 220 axially penetrates through the plurality of core segments 210 along the rotor core 200.

[0126] The rotating shaft 300 is inserted through the shaft hole 220.

[0127] Both the first bearing 400 and the second bearing 500 are sleeved on the rotating shaft 300.

[0128] The rotor core 200 is located between the first bearing 400 and the second bearing 500.

[0129] At least one of the first bearing 400 and the second bearing 500 is a four-point contact ball bearing.

[0130] The axial clearance δ of the four-point contact ball bearing, the minimum clearance lg between the cavity wall of the accommodating cavity 110 and the outer peripheral wall of the rotor core 200, the inner diameter R1 of the stator core 100, the outer diameter R2 of the stator core 100, the axial length Ls of the stator core 100, and the axial length Lr of the rotor core 200 satisfy: δ×(Lr + Ls) < 2×lg×(R2 - R1).

[0131] An electric power steering motor 10 provided in this application includes a stator core 100, a rotor core 200, a rotating shaft 300, a first bearing 400, and a second bearing 500.

[0132] The rotor core 200 includes a plurality of core segments 210 stacked axially along the rotor core 200. Among them, any two adjacent core segments 210 are arranged staggeredly in the clockwise direction, or any two adjacent core segments 210 are arranged staggeredly in the counterclockwise direction. That is to say, any two adjacent core segments 210 are arranged staggeredly in the circumferential direction of the rotor core 200 to form a rotor skew pole. The segmented modular setting of the rotor core 200 has the advantages of being convenient for installation and maintenance, and skew poles can be formed between the plurality of core segments 210.

[0133] Defining that any two adjacent core segments 210 are arranged staggeredly in the clockwise direction or in the counterclockwise direction can reduce the cogging torque and torque ripple, thereby reducing the electromagnetic vibration. That is to say, by dividing the rotor core 200 into a plurality of core segments 210 and arranging any two adjacent core segments 210 staggeredly in the clockwise direction or in the counterclockwise direction, the specific harmonic content in the electric power steering motor 10 can be effectively suppressed, the torque ripple and cogging torque of the electric power steering motor 10 can be improved, and thus the vibration and noise of the electric power steering motor 10 can be reduced.

[0134] Further, the rotor core 200 is provided with a shaft hole 220. The shaft hole 220 axially penetrates through a plurality of core segments 210 along the rotor core 200. The rotating shaft 300 is inserted into the shaft hole 220. The first bearing 400 is sleeved on the rotating shaft 300. The second bearing 500 is sleeved on the rotating shaft 300. The first bearing 400 is located outside the rotor core 200. The second bearing 500 is located outside the rotor core 200. Among them, the rotor core 200 is located between the first bearing 400 and the second bearing 500.

[0135] At least one of the first bearing 400 and the second bearing 500 is a four-point contact ball bearing. That is to say, the first bearing 400 is a four-point contact ball bearing. Or, the second bearing 500 is a four-point contact ball bearing. Or the first bearing 400 is a four-point contact ball bearing, and the second bearing 500 is a four-point contact ball bearing.

[0136] The four-point contact ball bearing can enhance the overall anti-deformation ability of the electric power steering motor 10, which is beneficial to improving the structural stiffness of the electric power steering motor 10, can reduce the axial end play when the electric power steering motor 10 is working. In this way, the vibration performance during the operation of the electric power steering motor 10 is further improved, the vibration noise of the electric power steering motor 10 can be further reduced, and the service performance and market competitiveness of the electric power steering motor 10 are greatly improved.

[0137] Further, the axial clearance of the four-point contact ball bearing is denoted as δ, the minimum value of the clearance between the cavity wall of the accommodation cavity 110 and the outer peripheral wall of the rotor core 200 is denoted as lg, the inner diameter of the stator core 100 is denoted as R1, the outer diameter of the stator core 100 is denoted as R2, and the axial length of the stator core 100 is denoted as Ls, and the axial length of the rotor core 200 is denoted as Lr. Among them, δ, lg, R1, R2, Ls, and Lr satisfy: δ×(Lr + Ls) < 2×lg×(R2 - R1). That is to say, the clearance of the four-point contact ball bearing and the matching structure of the stator core 100 and the rotor core 200 are limited. This setting can enhance the overall anti-deformation ability of the electric power steering motor 10, is beneficial to improving the structural stiffness of the electric power steering motor 10, can reduce the axial end play when the electric power steering motor 10 is working. In this way, the vibration performance during the operation of the electric power steering motor 10 is further improved, the vibration noise of the motor can be further reduced, and the service performance and market competitiveness of the motor are greatly improved.

[0138] It can be understood that when there is no load, the inner ring of the four-point contact ball bearing is fixed, and the displacement of the outer ring of the four-point contact ball bearing relative to the fixed inner ring along the axial direction of the rotor core 200 from one extreme position to another extreme position is denoted as the axial clearance of the four-point contact ball bearing. Or, when there is no load, the outer ring of the four-point contact ball bearing is fixed, and the displacement of the inner ring of the four-point contact ball bearing relative to the fixed outer ring along the axial direction of the rotor core 200 from one extreme position to another extreme position is denoted as the axial clearance of the four-point contact ball bearing.

[0139] When both the first bearing 400 and the second bearing 500 are four-point contact ball bearings, that is to say, four-point contact ball bearings are arranged on both axial sides of the rotor core 200. In this way, the matching area and matching angle between the first bearing 400, the second bearing 500 and the rotating shaft 300 are increased, the overall anti-deformation ability of the rotor can be further enhanced, the structural stiffness of the electric power steering motor 10 can be further improved, the axial end play when the electric power steering motor 10 is working can be reduced. In this way, the vibration performance during the operation of the electric power steering motor 10 is further improved, and the vibration noise of the electric power steering motor 10 can be further reduced.

[0140] In some embodiments, optionally, δ, lg, R1, R2, Ls, and Lr satisfy: 0 < (δ × (Lr + Ls)) / (2 × lg × (R2 - R1)) ≤ 0.8.

[0141] In this embodiment, the axial clearance δ of the four-point contact ball bearing, the minimum clearance lg between the cavity wall of the accommodation cavity 110 and the outer peripheral wall of the rotor core 200, the inner diameter R1 of the stator core 100, the outer diameter R2 of the stator core 100, the axial length Ls of the stator core 100, and the axial length Lr of the rotor core 200 are further defined in terms of their mating structure.

[0142] Specifically, δ, lg, R1, R2, Ls, and Lr satisfy: 0 < (δ × (Lr + Ls)) / (2 × lg × (R2 - R1)) ≤ 0.8. This enhances the overall anti-deformation ability of the electric power steering motor 10, is beneficial to improving the structural stiffness of the electric power steering motor 10, can reduce the axial end play when the electric power steering motor 10 is operating. In this way, the vibration performance during the operation of the electric power steering motor 10 is further improved, the vibration noise of the motor can be further reduced, and the service performance and market competitiveness of the motor are greatly improved.

[0143] Optionally, (δ × (Lr + Ls)) / (2 × lg × (R2 - R1)) = 0.1, (δ × (Lr + Ls)) / (2 × lg × (R2 - R1)) = 0.2, (δ × (Lr + Ls)) / (2 × lg × (R2 - R1)) = 0.3, (δ × (Lr + Ls)) / (2 × lg × (R2 - R1)) = 0.4, (δ × (Lr + Ls)) / (2 × lg × (R2 - R1)) = 0.5, (δ × (Lr + Ls)) / (2 × lg × (R2 - R1)) = 0.6, and (δ × (Lr + Ls)) / (2 × lg × (R2 - R1)) = 0.7, which are not listed one by one here.

[0144] In some embodiments, optionally, as Figure 2 and Figure 6 shown, the electric power steering motor 10 further includes a housing 600 and a first elastic part 700.

[0145] A first bearing cavity 610 and a second bearing cavity 620 are provided in the housing 600.

[0146] The stator core 100, the rotor core 200, the rotating shaft 300, the first bearing 400, and the second bearing 500 are all arranged in the housing 600.

[0147] The first bearing 400 is located in the first bearing cavity 610.

[0148] The second bearing 500 is located in the second bearing cavity 620.

[0149] The first elastic part 700 is arranged in the first bearing cavity 610.

[0150] The first elastic part 700 abuts between the side of the first bearing 400 facing away from the rotor core 200 and the cavity wall of the first bearing cavity 610.

[0151] The first elastic part 700 is used to apply an axial pre-tightening force to the first bearing 400.

[0152] Wherein, the first bearing 400 is in interference fit with the rotating shaft 300.

[0153] In this embodiment, the electric power steering motor 10 further includes a housing 600 and a first elastic part 700.

[0154] The stator core 100, the rotor core 200, the rotating shaft 300, the first bearing 400 and the second bearing 500 are all arranged in the housing 600. That is to say, the housing 600 serves as an installation carrier for the stator core 100, the rotor core 200, the rotating shaft 300, the first bearing 400 and the second bearing 500, and has the function of installing and fixing the stator core 100, the rotor core 200, the rotating shaft 300, the first bearing 400 and the second bearing 500 to ensure the mating dimensions of the stator core 100, the rotor core 200, the rotating shaft 300, the first bearing 400 and the second bearing 500.

[0155] The housing 600 is provided with a first bearing cavity 610 and a second bearing cavity 620. The first bearing cavity 610 is used for installing the first bearing 400, and the second bearing cavity 620 is used for installing the second bearing 500.

[0156] The first bearing 400 is in interference fit with the rotating shaft 300. The first elastic part 700 is arranged in the first bearing cavity 610. The first bearing 400 is located between the first elastic part 700 and the rotor core 200. The first elastic part 700 abuts against the first bearing 400, and the first elastic part 700 abuts against the cavity wall of the first bearing cavity 610. That is to say, the first elastic part 700 abuts between the side of the first bearing 400 facing away from the rotor core 200 and the cavity wall of the first bearing cavity 610. The first elastic part 700 is used to apply an axial pre-tightening force to the first bearing 400 so that the first bearing 400 is stably assembled on the rotating shaft 300.

[0157] It can be understood that after the electric power steering motor 10 is assembled, the first elastic part 700 is located between the first bearing 400 and the cavity wall of the first bearing cavity 610. By squeezing the first elastic part 700, the first elastic part 700 applies an axial pre-tightening force to the first bearing 400 to ensure the structural stiffness of the electric power steering motor 10 and is beneficial to reducing the axial movement amount during the operation of the electric power steering motor 10.

[0158] It can be understood that the cavity wall of the first bearing cavity 610 functions to limit the first bearing 400. Specifically, the cavity wall of the first bearing cavity 610 is used to radially limit the first bearing 400 on the rotating shaft 300.

[0159] In addition, the first bearing 400 and the rotating shaft 300 are in interference fit to axially and radially limit the first bearing 400 on the rotating shaft 300.

[0160] Optionally, the first elastic part 700 includes wave washers, springs, torsion springs, tension springs, etc., which will not be listed one by one here.

[0161] In some embodiments, optionally, as Figure 7 shown, there are fixed protrusions 622 provided in the second bearing cavity 620.

[0162] The fixed protrusion 622 abuts against the outer peripheral wall of the second bearing 500.

[0163] The second bearing 500 and the rotating shaft 300 are in interference fit.

[0164] In this embodiment, the mating structure of the housing 600 and the second bearing 500 is further defined.

[0165] Specifically, there are fixed protrusions 622 provided in the second bearing cavity 620, the fixed protrusion 622 abuts against the outer peripheral wall of the second bearing 500. Specifically, the fixed protrusion 622 is riveted to the outside of the second bearing 500, and the second bearing 500 and the rotating shaft 300 are in interference fit. The fixed protrusion 622 and the rotating shaft 300 cooperate to axially, radially and circumferentially limit the second bearing 500 along the rotating shaft 300. To improve the structural stiffness of the electric power steering motor 10, the axial movement amount during the operation of the electric power steering motor 10 can be reduced, and the overall anti-deformation ability of the electric power steering motor 10 can be enhanced. In this way, the vibration performance during the operation of the electric power steering motor 10 is further improved, the vibration noise of the electric power steering motor 10 can be further reduced, and the service performance and market competitiveness of the electric power steering motor 10 are greatly improved.

[0166] Optionally, the number of the fixed protrusions 622 is multiple, and the multiple fixed protrusions 622 are arranged at intervals along the circumferential direction of the rotating shaft 300.

[0167] In some embodiments, optionally, when one of the first bearing 400 and the second bearing 500 is a four-point contact ball bearing, the second bearing 500 is a four-point contact ball bearing.

[0168] In this embodiment, the types of the first bearing 400 and the second bearing 500 are further defined.

[0169] Specifically, when one of the first bearing 400 and the second bearing 500 is a four-point contact ball bearing, the second bearing 500 is a four-point contact ball bearing and the first bearing 400 is a non-four-point contact ball bearing.

[0170] In some other embodiments, the second bearing 500 is a non-four-point contact ball bearing and the first bearing 400 is a four-point contact ball bearing.

[0171] In some embodiments, optionally, the axial clearance of the second bearing 500 is less than or equal to 0.1 mm.

[0172] In this embodiment, the value range of the axial clearance δ of the second bearing 500 is further limited such that δ ≤ 0.1 mm. In this way, the axial vibration of the electric power steering motor 10 can be further optimized to further optimize the vibration noise of the electric power steering motor 10.

[0173] In some embodiments, optionally, as Figure 2 and Figure 6 shown, along the axial direction of the rotating shaft 300, the minimum distance between the end faces of the second bearing 500 and the rotor core 200 close to each other is d; where 0.025 ≤ (2×d) / (Lr + Ls) ≤ 1.25.

[0174] In this embodiment, the mating structure of the second bearing 500 and the rotor core 200 is further limited.

[0175] Along the axial direction of the rotating shaft 300, the minimum distance between the end faces of the second bearing 500 and the rotor core 200 close to each other is d. That is, along the axial direction of the rotating shaft 300, the end face of the second bearing 500 facing the rotor core 200 is the first end face, and the end face of the rotor core 200 facing the second bearing 500 is the second end face, and the minimum distance between the first end face and the second end face is d.

[0176] Wherein, d, Lr and Ls satisfy 0.025 ≤ (2×d) / (Lr + Ls) ≤ 1.25. The smaller the distance d, the greater the axial force on the second bearing 500 affected by magnetic leakage. The larger the distance d, the higher the production cost will be. That is to say, d, Lr and Ls satisfy 0.025 ≤ (2×d) / (Lr + Ls) ≤ 1.25, taking into account both the axial force on the second bearing 500 and the production cost of the product. The cost of the product is controlled within a reasonable range, and the axial force on the second bearing 500 is relatively optimal, with the highest cost performance.

[0177] Optionally, (2×d) / (Lr + Ls) = 0.05, (2×d) / (Lr + Ls) = 0.075, (2×d) / (Lr + Ls) = 0.1, etc., which are not listed one by one here.

[0178] In some embodiments, optionally, as Figure 8 shown, a first card slot 630 is further provided in the housing 600.

[0179] The first card slot 630 is located on the side of the second bearing cavity 620 facing the first bearing cavity 610.

[0180] And the first card slot 630 communicates with the second bearing cavity 620.

[0181] The electric power steering motor 10 further includes a second elastic part 800.

[0182] The second elastic part 800 is disposed in the first card slot 630.

[0183] The second elastic part 800 is arranged around the rotating shaft 300.

[0184] And the second elastic part 800 abuts against the second bearing 500.

[0185] The second elastic part 800 is used to limit the axial displacement of the second bearing 500.

[0186] The second bearing 500 has an interference fit with the rotating shaft 300.

[0187] In this embodiment, the mating structure of the rotating shaft 300 and the second bearing 500 is further defined.

[0188] A first card slot 630 is further provided in the housing 600. The first card slot 630 is located on the side of the second bearing cavity 620 facing the first bearing cavity 610, and the first card slot 630 communicates with the second bearing cavity 620.

[0189] The electric power steering motor 10 further includes a second elastic part 800. The first card slot 630 is used for installing and fixing the second elastic part 800. The second elastic part 800 is disposed in the first card slot 630. The second elastic part 800 is arranged around the rotating shaft 300, and the second elastic part 800 abuts against the second bearing 500. The second elastic part 800 is used to axially limit the second bearing 500 along the rotating shaft 300 to ensure the mating dimensions of the second bearing 500 and the rotating shaft 300. It is beneficial to improve the stability and reliability of the assembly of the rotating shaft 300 and the second bearing 500, enhance the overall anti-deformation ability of the electric power steering motor 10, and reduce the frictional torque of the electric power steering motor 10.

[0190] The second bearing 500 has an interference fit with the rotating shaft 300. The rotating shaft 300 and the second elastic part 800 cooperate to stably assemble the second bearing 500 and the rotating shaft 300 together.

[0191] The rotating shaft 300 and the second elastic part 800 cooperate to limit the second bearing 500 axially, radially and circumferentially along the rotating shaft 300. This can improve the structural stiffness of the electric power steering motor 10, reduce the axial runout of the electric power steering motor 10 during operation, and enhance the overall anti-deformation ability of the electric power steering motor 10. In this way, the vibration performance of the electric power steering motor 10 during operation is further improved, the vibration noise of the electric power steering motor 10 can be further reduced, and the service performance and market competitiveness of the electric power steering motor 10 are greatly improved.

[0192] In addition, the second bearing 500 is a four-point contact ball bearing, the second bearing 500 is in interference fit with the rotating shaft 300, and the second elastic part 800 restricts the axial displacement of the second bearing 500. This setting can reduce the influence on the radial clearance of the second bearing 500 and ensure the radial clearance of the second bearing 500. In this way, it is beneficial to reduce the frictional torque of the electric power steering motor 10 during operation. That is to say, this setting takes into account reducing the vibration noise of the electric power steering motor 10 and reducing the frictional torque of the electric power steering motor 10, improving the service performance and market competitiveness of the product.

[0193] Optionally, the second elastic part 800 includes springs, torsion springs, tension springs, etc., which are not listed one by one here.

[0194] It can be understood that when there is no load, the inner ring of the second bearing 500 is fixed, and the displacement of the outer ring of the second bearing 500 relative to the fixed inner ring from one extreme position to another extreme position in the radial direction of the rotor core 200 is denoted as the radial clearance of the second bearing 500.

[0195] In some embodiments, optionally, as Figure 9 shown, the end face of the second bearing 500 facing the rotor core 200 is connected to the outer peripheral wall of the rotating shaft 300 through a welding fixing part 1100.

[0196] The second bearing 500 is in clearance fit with the rotating shaft 300.

[0197] In this embodiment, the mating structure between the rotating shaft 300 and the second bearing 500 is further defined.

[0198] Specifically, the second bearing 500 is in clearance fit with the rotating shaft 300, and the end face of the second bearing 500 facing the rotor core 200 is connected to the outer peripheral wall of the rotating shaft 300 through a welding fixing part 1100. That is to say, the welding fixing part 1100 firmly assembles the second bearing 500 and the rotating shaft 300 together.

[0199] The welding fixing part 1100 and the rotating shaft 300 cooperate to limit the second bearing 500 axially, radially, and circumferentially along the rotating shaft 300. This improves the structural stiffness of the electric power steering motor 10, can reduce the axial movement amount during the operation of the electric power steering motor 10, and enhances the overall anti-deformation ability of the electric power steering motor 10. In this way, the vibration performance during the operation of the electric power steering motor 10 is further improved, the vibration noise of the electric power steering motor 10 can be further reduced, and the service performance and market competitiveness of the electric power steering motor 10 are greatly improved.

[0200] In addition, the second bearing 500 is a four-point contact ball bearing, and the second bearing 500 and the rotating shaft 300 are stably assembled through the welding fixing part 1100. This setting can reduce the influence on the radial clearance of the second bearing 500 and ensure the radial clearance of the second bearing 500. In this way, it is beneficial to reduce the frictional torque during the operation of the electric power steering motor 10. That is to say, this setting takes into account reducing the vibration noise of the electric power steering motor 10 and reducing the frictional torque of the electric power steering motor 10, improving the service performance and market competitiveness of the product.

[0201] It can be understood that when there is no load, the inner ring of the second bearing 500 is fixed, and the displacement amount of the outer ring of the second bearing 500 relative to the fixed inner ring from one extreme position to another extreme position along the radial direction of the rotor core 200 is denoted as the radial clearance of the second bearing 500.

[0202] In some embodiments, optionally, as Figure 9 shown, a second card slot 640 is further provided in the housing 600.

[0203] The second card slot 640 is located on the side of the second bearing cavity 620 facing the first bearing cavity 610, and the second card slot 640 communicates with the second bearing cavity 620.

[0204] The electric power steering motor 10 further includes a third elastic part 1000.

[0205] The third elastic part 1000 is disposed in the second card slot 640.

[0206] The third elastic part 1000 is disposed around the rotating shaft 300.

[0207] And the third elastic part 1000 abuts against the second bearing 500.

[0208] The third elastic part 1000 is used to limit the axial displacement of the second bearing 500.

[0209] In this embodiment, the mating structure of the housing 600 and the second bearing 500 is further defined.

[0210] A second card slot 640 is further provided inside the housing 600. The second card slot 640 is located on the side of the second bearing cavity 620 facing the first bearing cavity 610, and the second card slot 640 communicates with the second bearing cavity 620.

[0211] The electric power steering motor 10 further includes a third elastic part 1000. The second card slot 640 is used for installing and fixing the third elastic part 1000. The third elastic part 1000 is disposed in the second card slot 640. The third elastic part 1000 is arranged around the rotating shaft 300, and the third elastic part 1000 abuts against the second bearing 500. The third elastic part 1000 is used for axially limiting the second bearing 500 along the rotating shaft 300 to ensure the matching dimensions of the second bearing 500 and the rotating shaft 300. It is beneficial to improve the stability and reliability of the assembly of the rotating shaft 300 and the second bearing 500, enhance the overall anti-deformation ability of the electric power steering motor 10, and reduce the friction torque of the electric power steering motor 10.

[0212] The welding fixing part 1100 and the third elastic part 1000 cooperate to reduce the vibration noise of the electric power steering motor 10 while ensuring the radial clearance of the second bearing 500, enhance the anti-deformation ability of the electric power steering motor 10, and reduce the friction torque of the electric power steering motor 10. That is to say, this setting takes into account reducing the vibration noise of the electric power steering motor 10 and reducing the friction torque of the electric power steering motor 10, improving the service performance and market competitiveness of the product.

[0213] In some embodiments, optionally, as Figure 11 shown, each iron core segment 210 includes a plurality of rotor punching sheets 212.

[0214] A plurality of rotor punching sheets 212 are stacked.

[0215] As Figure 10 shown, the stator iron core 100 includes a plurality of stator punching sheets 120.

[0216] A plurality of stator punching sheets 120 are stacked.

[0217] Among any two adjacent rotor punching sheets 212, one rotor punching sheet 212 is provided with a first convex part 230, and the other rotor punching sheet 212 is provided with a first groove 240.

[0218] The first convex part 230 and the first groove 240 are in interference fit.

[0219] Among any two adjacent stator punching sheets 120, one stator punching sheet 120 is provided with a second convex part 130, and the other stator punching sheet 120 is provided with a second groove 140.

[0220] The second convex part 130 and the second groove 140 are in interference fit.

[0221] In this embodiment, each iron core segment 210 includes a plurality of rotor punching sheets 212, and the plurality of rotor punching sheets 212 are stacked.

[0222] Among any two adjacent rotor punching sheets 212, one rotor punching sheet 212 is provided with a first convex portion 230, and the other rotor punching sheet 212 is provided with a first groove 240, and the first convex portion 230 and the first groove 240 are in interference fit.

[0223] Specifically, a first groove 240 is provided on the axial end face of the first side of each rotor punching sheet 212, and a first convex portion 230 is provided on the axial end face of the second side of each rotor punching sheet 212. That is, along the axial direction of the rotor core 200, the rotor punching sheet 212 has a first end face and a second end face which are oppositely arranged, the first end face is provided with the first groove 240, and the second end face is provided with the first convex portion 230.

[0224] When two adjacent rotor punching sheets 212 are assembled, the first convex portion 230 is inserted into the first groove 240, and the first convex portion 230 and the first groove 240 are in interference fit to achieve the purpose of assembling the two rotor punching sheets 212.

[0225] The first convex portion 230 and the first groove 240 cooperate to increase the contact area and contact angle between two adjacent rotor punching sheets 212, which is beneficial to improving the stability and reliability of the assembly of two adjacent rotor punching sheets 212 in the axial direction of the rotor core 200, preventing the rotor punching sheets 212 from being scattered, and ensuring the structural stiffness of the assembly of the rotor core 200.

[0226] In this embodiment, the stator core 100 includes a plurality of stator punching sheets 120, and the plurality of stator punching sheets 120 are stacked.

[0227] Among any two adjacent stator punching sheets 120, one stator punching sheet 120 is provided with a second convex portion 130, and the other stator punching sheet 120 is provided with a second groove 140, and the second convex portion 130 and the second groove 140 are in interference fit.

[0228] Specifically, a second groove 140 is provided on the axial end face of the first side of each stator punching sheet 120, and a second convex portion 130 is provided on the axial end face of the second side of each stator punching sheet 120. That is, along the axial direction of the stator core 100, the stator punching sheet 120 has a first end face and a second end face which are oppositely arranged, the first end face is provided with the second groove 140, and the second end face is provided with the second convex portion 130.

[0229] When two adjacent stator punching sheets 120 are assembled, the second convex portion 130 is inserted into the second groove 140, and the second convex portion 130 and the second groove 140 are in interference fit to achieve the purpose of assembling the two stator punching sheets 120.

[0230] The second convex portion 130 and the second groove 140 cooperate to increase the contact area and contact angle between two adjacent stator laminations 120, which is beneficial to improving the stability and reliability of the assembly of two adjacent stator laminations 120 in the axial direction of the stator core 100, preventing the stator laminations 120 from being scattered, and ensuring the structural stiffness of the assembled stator core 100.

[0231] In some embodiments, optionally, as Figure 3 shown, the stator core 100 includes a plurality of stator core blocks 150.

[0232] The plurality of stator core blocks 150 are connected end to end in sequence around the axis of the shaft hole 220.

[0233] The center of the circle corresponding to the outer peripheral wall 152 of the stator core block coincides with the center of the circle corresponding to the inner peripheral wall 154 of the stator core block.

[0234] In this embodiment, the stator core 100 includes a plurality of stator core blocks 150, and the plurality of stator core blocks 150 are connected end to end in sequence around the axis of the shaft hole 220.

[0235] Among them, the center of the circle corresponding to the outer peripheral wall 152 of the stator core block coincides with the center of the circle corresponding to the inner peripheral wall 154 of the stator core block.

[0236] That is to say, the stator core 100 has a structure of a segmented core, and the plurality of stator core blocks 150 are connected end to end in sequence around the axis of the shaft hole 220. This setting can greatly improve the slot fill factor of the electric power steering motor 10, further improve the power density of the electric power steering motor 10, and ensure that the product performance requirements are met without using heavy rare earth elements.

[0237] In some embodiments, optionally, as Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6 shown, the rotor core 200 is further provided with a plurality of magnet slots 250.

[0238] The plurality of magnet slots 250 are arranged at intervals along the circumferential direction of the rotating shaft 300.

[0239] And the magnet slots 250 are located between the shaft hole 220 and the outer peripheral wall of the rotor core 200.

[0240] The electric power steering motor 10 further includes a plurality of permanent magnets 900.

[0241] Each permanent magnet 900 is disposed in a magnet slot 250.

[0242] In this embodiment, the specific structure of the electric power steering motor 10 is further defined.

[0243] A portion of the rotor core 200 located between the shaft hole 220 and the outer peripheral wall of the rotor core 200 is provided with a plurality of magnet slots 250, and the plurality of magnet slots 250 are arranged at intervals in the circumferential direction of the rotating shaft 300.

[0244] The electric power assisted steering motor 10 further includes a plurality of permanent magnets 900, and each permanent magnet 900 is disposed in one magnet slot 250. That is, the plurality of permanent magnets 900 are disposed on the rotor core 200, and the plurality of permanent magnets 900 are arranged at intervals in the circumferential direction of the rotating shaft 300. The permanent magnet 900 is located between the shaft hole 220 and the outer peripheral wall of the rotor core 200.

[0245] In some embodiments, optionally, as Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 and Figure 6 shown, the rotor core 200 is further provided with a plurality of weight reduction holes 260.

[0246] The plurality of weight reduction holes 260 are arranged at intervals in the circumferential direction of the rotating shaft 300.

[0247] The weight reduction hole 260 is located between the rotating shaft 300 and the permanent magnet 900.

[0248] The number of the weight reduction holes 260 is greater than or equal to the number of pole pairs of the electric power assisted steering motor 10.

[0249] In this embodiment, the structure of the rotor core 200 is further defined such that the rotor core 200 is provided with a plurality of weight reduction holes 260, the plurality of weight reduction holes 260 are arranged at intervals around the circumferential direction of the rotating shaft 300, and the weight reduction hole 260 is located between the rotating shaft 300 and the permanent magnet 900. The weight reduction hole 260 has the function of reducing the overall weight of the electric power assisted steering motor 10.

[0250] In addition, any two adjacent iron core segments 210 are arranged in a staggered manner in the clockwise direction or the counterclockwise direction, that is, any two adjacent iron core segments 210 are arranged in a staggered manner in the circumferential direction of the rotor core 200 to form a rotor skewed pole. The weight reduction hole 260 can be used as a positioning basis to assemble the rotor core 200, providing a reliable structural support for ensuring the formation of the rotor skewed pole.

[0251] Furthermore, the number of the weight reduction holes 260 is greater than or equal to the number of pole pairs of the electric power assisted steering motor 10, and the plurality of weight reduction holes 260 are arranged at intervals around the circumferential direction of the rotating shaft 300. In this way, when assembling the rotor core 200, the plurality of iron core segments 210 can be positioned from multiple directions and multiple angles, and the matching accuracy of the plurality of iron core segments 210 can be ensured.

[0252] Optionally, the number of the weight reduction holes 260 is equal to the number of pole pairs of the electric power assisted steering motor 10.

[0253] Optionally, weight-reducing holes 260 are provided on the magnetic pole center line and / or the inter-pole center line of the rotor core 200. This is to reduce the moment of inertia and the overall weight of the electric power steering motor 10 while ensuring that the performance of the electric power steering motor 10 is not affected.

[0254] In some embodiments, optionally, at least a part of the hole wall of the shaft hole 220 is in interference fit with the rotating shaft 300.

[0255] In this embodiment, the mating structure between the rotor core 200 and the rotating shaft 300 is defined.

[0256] At least a part of the hole wall of the shaft hole 220 is in interference fit with the rotating shaft 300. That is, a part of the hole wall of the shaft hole 220 is in interference fit with the rotating shaft 300. Or the entire hole wall of the shaft hole 220 is in interference fit with the rotating shaft 300.

[0257] This setting can ensure the mating structure between the rotating shaft 300 and the rotor core 200 and prevent the separation of the rotating shaft 300 and the rotor core 200.

[0258] When a part of the hole wall of the shaft hole 220 is in interference fit with the rotating shaft 300, the contact area between the shaft hole 220 and the rotating shaft 300 can be reduced. That is, while ensuring the use requirement of the interference fit between the rotating shaft 300 and the shaft hole 220, the radial force formed by the interference fit between the shaft hole 220 and the rotating shaft 300 can be reduced due to the reduction of the contact area between the shaft hole 220 and the rotating shaft 300. This can reduce the influence of the radial force on the bonding force between the rotor laminations 212 of the rotor core 200, which is beneficial to reducing the probability of deformation of the rotor laminations 212 of the rotor core 200 and further reducing the probability of loosening of the multiple rotor laminations 212 of the rotor core 200.

[0259] Optionally, the hole wall of the shaft hole 220 is a concave-convex wall. The protrusions of the concave-convex wall are in interference fit with the rotating shaft 300, and the depressions of the concave-convex wall are arranged separately from the rotating shaft 300. The protrusions and depressions of the concave-convex wall are arranged alternately, and both the protrusions and depressions extend along the axial direction of the rotating shaft 300.

[0260] An electric power steering system according to still some other embodiments of the present application includes: the electric power steering motor 10 as described in any of the above embodiments.

[0261] An electric power steering system provided by the present application includes the electric power steering motor 10 as described in any of the above embodiments. Therefore, it has all the beneficial effects of the above electric power steering motor 10, which will not be elaborated one by one here.

[0262] A vehicle according to still some other embodiments of the present application includes: the electric power steering motor 10 as described in any of the above embodiments; or the electric power steering system as described in the above embodiments.

[0263] A vehicle provided in the present application includes an electric power steering motor 10 as in any of the above embodiments, or includes an electric power steering system as in the above embodiments, and therefore has all the beneficial effects of the above electric power steering motor 10 or electric power steering system, which are not described one by one here.

[0264] It is worth noting that the vehicle can be a new energy vehicle, which includes pure electric vehicles, extended-range electric vehicles, hybrid electric vehicles, fuel cell electric vehicles and hydrogen engine vehicles.

[0265] The vehicle can also be a fuel vehicle or a hybrid vehicle.

[0266] Optionally, the present application can enhance the overall anti-deformation ability of the electric power steering motor 10 by setting a four-point contact ball bearing, which is beneficial to improving the structural stiffness of the electric power steering motor 10 and can reduce the axial movement of the electric power steering motor 10 during operation. In this way, the vibration performance of the electric power steering motor 10 during operation is further improved, and the vibration noise of the electric power steering motor 10 can be further reduced, thereby greatly improving the performance and market competitiveness of the electric power steering motor 10.

[0267] Optionally, the electric power steering motor 10 includes a stator core 100 and a rotor core 200. An accommodating cavity 110 is provided at the inner diameter of the stator core 100, and the accommodating cavity 110 is used to accommodate the rotor core 200. The rotor core 200 includes a plurality of core segments 210, and the plurality of core segments 210 are stacked, and any two adjacent core segments 210 are staggered in a clockwise direction or in a counterclockwise direction. The rotor core 200 is provided with an axial hole 220, and the axial hole 220 penetrates the plurality of core segments 210 along the axial direction of the rotor core 200.

[0268] The electric power steering motor 10 further includes a rotating shaft 300 , a first bearing 400 and a second bearing 500 . The rotating shaft 300 is passed through the shaft hole 220 .

[0269] The first bearing 400 and the second bearing 500 are both sleeved on the rotating shaft 300 , and the rotor core 200 is located between the first bearing 400 and the second bearing 500 .

[0270] At least one of the first bearing 400 and the second bearing 500 is a four-point contact ball bearing.

[0271] The axial clearance δ of the four-point contact ball bearing, the minimum gap lg between the cavity wall of the accommodating cavity 110 and the outer peripheral wall of the rotor core 200, the inner diameter R1 of the stator core 100, the outer diameter R2 of the stator core 100, the axial length Ls of the stator core 100 and the axial length Lr of the rotor core 200 satisfy 0<(δ×(Lr+Ls)) / (2×lg×(R2-R1))≤0.8.

[0272] Each iron core segment 210 includes a plurality of stacked rotor punching sheets 212. The rotor iron core 200 is provided with a connecting structure, and any two adjacent rotor punching sheets 212 are connected through the connecting structure.

[0273] The stator iron core 100 includes a plurality of stator core blocks 150. The plurality of stator core blocks 150 are assembled into a circular shape by welding to form the stator iron core 100. The outer edge and the inner edge of the stator core block 150 are two concentric circular arcs.

[0274] The stator iron core 100 includes a plurality of stacked stator punching sheets 120. The stator iron core 100 is provided with a connecting structure similar to that of the rotor iron core 200, and any two adjacent stator punching sheets 120 are connected through the connecting structure.

[0275] The connecting structure includes a convex portion and a groove. Among any two adjacent rotor punching sheets 212, one rotor punching sheet 212 is provided with a first convex portion 230, and the other rotor punching sheet 212 is provided with a first groove 240. The first convex portion 230 and the first groove 240 are in interference fit; among any two adjacent stator punching sheets 120, one stator punching sheet 120 is provided with a second convex portion 130, and the other stator punching sheet 120 is provided with a second groove 140. The second convex portion 130 and the second groove 140 are in interference fit.

[0276] The electric power steering motor 10 further includes: a plurality of permanent magnets 900. The plurality of permanent magnets 900 are arranged on the iron core segment 210, and the plurality of permanent magnets 900 are arranged at intervals along the circumferential direction of the shaft hole 220. Along the axial direction of the rotor iron core 200, the length of the permanent magnet 900 is less than or equal to the length of the iron core segment 210.

[0277] The rotor iron core 200 is provided with a plurality of weight reduction holes 260. The plurality of weight reduction holes 260 are arranged at intervals along the circumferential direction of the rotating shaft 300, and the number of the weight reduction holes 260 is greater than or equal to the number of pole pairs of the electric power steering motor 10.

[0278] At least a part of the hole wall of the shaft hole 220 is in interference fit with the rotating shaft 300.

[0279] The electric power steering motor 10 further includes a first elastic part 700. The first elastic part 700 is sleeved on the rotating shaft 300. The first bearing 400 is located between the first elastic part 700 and the rotor iron core 200, and the first elastic part 700 is used to apply an axial pre-tightening force to the first bearing 400.

[0280] The second bearing 500 is riveted and fixed in the second bearing cavity 620 through the fixing protrusion 622 of the second bearing cavity 620. Along the axial direction of the rotating shaft 300, the minimum distance between the end faces of the second bearing 500 and the rotor iron core 200 close to each other is d; wherein, 0.025 ≤ (2×d) / (Lr + Ls) ≤ 1.25.

[0281] The axial clearance δ of the second bearing 500 is less than or equal to 0.1 mm.

[0282] The electric power assisted steering motor 10 includes: a stator core 100 which is formed by assembling a plurality of stator core blocks 150 in a circular shape, and each stator core block 150 is formed by stacking a plurality of stator punching sheets 120; a rotor core 200 which includes a plurality of core segments 210 stacked together, and any two adjacent core segments 210 are arranged staggeredly in the clockwise or counterclockwise direction, and the rotor core 200 is provided with a shaft hole 220; a rotating shaft 300 which is inserted through the shaft hole 220; a first bearing 400 and a second bearing 500, at least one of the first bearing 400 and the second bearing 500 is a four-point contact ball bearing, both the first bearing 400 and the second bearing 500 are sleeved on the rotating shaft 300, the rotor core 200 is located between the first bearing 400 and the second bearing 500, the first bearing 400 is located between the first elastic part 700 and the rotor core 200, the first elastic part 700 is used to apply an axial pre-tightening force to the first bearing 400, the axial clearance δ of the second bearing 500 is less than or equal to 0.1 mm, and 0 < (δ × (Lr + Ls)) / (2 × lg × (R2 - R1)) ≤ 0.8 is satisfied.

[0283] The four-point contact ball bearing can enhance the overall anti-deformation ability of the electric power assisted steering motor 10, is beneficial to improving the structural stiffness of the electric power assisted steering motor 10, can reduce the axial end-play when the electric power assisted steering motor 10 is working. In this way, the vibration performance of the electric power assisted steering motor 10 during operation is further improved, the vibration noise of the electric power assisted steering motor 10 can be further reduced, and the service performance and market competitiveness of the electric power assisted steering motor 10 are greatly improved.

[0284] The electric power assisted steering motor 10 includes a rotor core 200, a plurality of permanent magnets 900, a rotating shaft 300, a first bearing 400, a second bearing 500 and a first elastic part 700. The rotor core 200 includes a plurality of core segments 210 stacked along the axial direction of the rotor core 200, and any two adjacent core segments 210 are arranged staggeredly in the clockwise or counterclockwise direction. This setting can reduce the cogging torque and torque ripple, thereby reducing the electromagnetic vibration. Along the axial direction of the rotor core 200, the length of the permanent magnet 900 is less than or equal to the length of the core segment 210, and the core segment 210 has the function of protecting the permanent magnet 900. In this way, the probability of squeezing the permanent magnet 900 and then causing damage to the permanent magnet 900 can be reduced.

[0285] The rotor core 200 is in interference fit with the rotating shaft 300, the first bearing 400 is in interference fit with the rotating shaft 300, and the second bearing 500 is in interference fit with the rotating shaft 300. This is beneficial to improving the overall structural rigidity of the rotor core 200, the rotating shaft 300, the first bearing 400 and the second bearing 500, and enhancing the overall anti-deformation ability of the rotor core 200, multiple permanent magnets 900, the rotating shaft 300, the first bearing 400 and the second bearing 500, so as to reduce the axial movement amount during the operation of the electric power steering motor 10.

[0286] At least one of the first bearing 400 and the second bearing 500 is a four-point contact ball bearing. Both the first bearing 400 and the second bearing 500 are sleeved on the rotating shaft 300. The axial clearance δ of the four-point contact ball bearing, the minimum clearance lg between the wall of the accommodation cavity 110 and the outer peripheral wall of the rotor core 200, the inner diameter R1 of the stator core 100, the outer diameter R2 of the stator core 100, the axial length Ls of the stator core 100 and the axial length Lr of the rotor core 200 satisfy 0 < (δ × (Lr + Ls)) / (2 × lg × (R2 - R1)) ≤ 0.8, and the axial clearance δ of the four-point contact ball bearing is less than or equal to 0.1 mm. As Figure 13 shown, let (δ × (Lr + Ls)) / (2 × lg × (R2 - R1)) be X. When X changes, taking a 12-slot 8-pole permanent magnet motor as an example, the number of pole pairs p = 4. Figure 13 The figure shows the simulation results of the 24th-order noise under different X values, where Lp is the per-unit value, and Lp is the ratio of the 24th-order noise of the motor under different X values to the 24th-order noise of the motor in the related technology. In the range of 0 < X ≤ 0.8, the 24th-order noise of the motor is better and the cost performance is the highest.

[0287] The motor further includes a first elastic part 700. The first elastic part 700 is sleeved on the rotating shaft 300, and the first bearing 400 is located between the first elastic part 700 and the rotor core 200. The first elastic part 700 is used to apply an axial pre-tightening force to the first bearing 400. The second bearing 500 is riveted and fixed in the second bearing cavity 620 through a fixing protrusion 622. Along the axial direction of the rotating shaft 300, the minimum distance between the end faces of the second bearing 500 and the rotor core 200 that are close to each other is d; where 0.025 ≤ (2 × d) / (Lr + Ls) ≤ 1.25. The smaller the distance d is, the greater the axial force on the second bearing 500 due to the influence of magnetic flux leakage will be, but the larger the distance d is, the higher the cost will be. Let (2 × d) / (Lr + Ls) be V, Figure 14 The figure shows the changes in the axial force and cost of the second bearing 500 under different V values. The ordinate Y is the per-unit value, which is the ratio of the axial force or cost under different V values to the axial force or cost of the motor in the related technology. In the range of 0.025 ≤ V ≤ 1.25, the cost is controlled within a reasonable range, the axial force is better, and the cost performance is the highest.

[0288] Optionally, as Figure 6 shown, the housing 600 includes a casing 650 and an end cap 660.

[0289] At least one of the first bearing 400 and the second bearing 500 is a four-point contact ball bearing. That is, the first bearing 400 is a four-point contact ball bearing. Or, the second bearing 500 is a four-point contact ball bearing. Or the first bearing 400 is a four-point contact ball bearing and the second bearing 500 is a four-point contact ball bearing.

[0290] The axial clearance of the four-point contact ball bearing is denoted as δ, the minimum value of the clearance between the cavity wall of the accommodation cavity 110 and the outer peripheral wall of the rotor core 200 is denoted as lg, the inner diameter of the stator core 100 is denoted as R1, the outer diameter of the stator core 100 is denoted as R2, and the axial length of the stator core 100 is denoted as Ls, and the axial length of the rotor core 200 is denoted as Lr. Among them, δ, lg, R1, R2, Ls, and Lr satisfy: δ×(Lr + Ls) < 2×lg×(R2 - R1). That is, the clearance of the four-point contact ball bearing and the matching structure of the stator core 100 and the rotor core 200 are limited. This setting can enhance the overall anti-deformation ability of the electric power steering motor 10, is beneficial to improving the structural stiffness of the electric power steering motor 10, can reduce the axial movement amount during the operation of the electric power steering motor 10. In this way, the vibration performance during the operation of the electric power steering motor 10 is further improved, the vibration noise of the motor can be further reduced, and the service performance and market competitiveness of the motor are greatly improved.

[0291] It can be understood that when there is no load, the inner ring of the four-point contact ball bearing is fixed, and the displacement of the outer ring of the four-point contact ball bearing relative to the fixed inner ring along the axial direction of the rotor core 200 from one extreme position to another extreme position is denoted as the axial clearance of the four-point contact ball bearing. Or, when there is no load, the outer ring of the four-point contact ball bearing is fixed, and the displacement of the inner ring of the four-point contact ball bearing relative to the fixed outer ring along the axial direction of the rotor core 200 from one extreme position to another extreme position is denoted as the axial clearance of the four-point contact ball bearing.

[0292] Optionally, δ, lg, R1, R2, Ls, and Lr satisfy: 0 < (δ×(Lr + Ls)) / (2×lg×(R2 - R1)) ≤ 0.8.

[0293] In this application, the term "a plurality of" means two or more, unless otherwise clearly defined. Terms such as "mounted", "connected", "connected to", "fixed" and other terms should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0294] In the description of this specification, the descriptions of terms such as "one embodiment", "some embodiments", "specific embodiments", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or instance. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. The above is only the preferred embodiment of the present application and is not used to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. An electric power steering motor, characterized in that: include: A stator core, wherein the stator core is provided with a receiving cavity; A rotor core is disposed in the accommodating cavity, the rotor core comprises a plurality of core segments, the plurality of core segments are stacked, any two adjacent core segments are staggered in a clockwise direction or in a counterclockwise direction, and the rotor core is provided with an axial hole, the axial hole penetrates the plurality of core segments in the axial direction of the rotor core; A rotating shaft, passing through the shaft hole; First bearing; a second bearing, wherein the first bearing and the second bearing are both sleeved on the rotating shaft, the rotor core is located between the first bearing and the second bearing, and at least one of the first bearing and the second bearing is a four-point contact ball bearing; The axial clearance δ of the four-point contact ball bearing, the minimum gap lg between the cavity wall of the accommodating cavity and the outer peripheral wall of the rotor core, the inner diameter R1 of the stator core, the outer diameter R2 of the stator core, the axial length Ls of the stator core and the axial length Lr of the rotor core satisfy: δ×(Lr+Ls)<2×lg×(R2-R1).

2. The electric power steering motor according to claim 1, characterized in that: δ, lg, R1, R2, Ls and Lr satisfy: 0<(δ×(Lr+Ls)) / (2×lg×(R2-R1))≤0.

8.

3. The electric power steering motor according to claim 1 or 2, characterized in that: Also includes: A housing, wherein a first bearing cavity and a second bearing cavity are disposed in the housing, wherein the stator core, the rotor core, the rotating shaft, the first bearing and the second bearing are all disposed in the housing, wherein the first bearing is located in the first bearing cavity, and the second bearing is located in the second bearing cavity; a first elastic portion, disposed in the first bearing cavity, the first elastic portion abutting between a side of the first bearing away from the rotor core and a cavity wall of the first bearing cavity, the first elastic portion being used to apply an axial preload force to the first bearing; Wherein, the first bearing and the rotating shaft are interference fit.

4. The electric power steering motor according to claim 3, characterized in that: A fixing protrusion is provided in the second bearing cavity, the fixing protrusion abuts against the outer peripheral wall of the second bearing, and the second bearing is interference fit with the rotating shaft.

5. The electric power steering motor according to claim 4, characterized in that: When one of the first bearing and the second bearing is a four-point contact ball bearing, the second bearing is a four-point contact ball bearing.

6. The electric power steering motor according to claim 5, characterized in that: The axial clearance of the second bearing is less than or equal to 0.1 mm.

7. The electric power steering motor according to claim 4, characterized in that: Along the axial direction of the rotating shaft, the minimum distance between the second bearing and the end faces of the rotor core close to each other is d; Among them, 0.025≤(2×d) / (Lr+Ls)≤1.

25.

8. The electric power steering motor according to claim 3, characterized in that: A first slot is further provided in the housing, the first slot is located on a side of the second bearing cavity facing the first bearing cavity, and the first slot is communicated with the second bearing cavity; The electric power steering motor also includes a second elastic part, which is arranged in the first slot, is arranged around the rotating shaft, and is in contact with the second bearing. The second elastic part is used to limit the axial displacement of the second bearing, and the second bearing is interference fit with the rotating shaft.

9. The electric power steering motor according to claim 3, characterized in that: The end surface of the second bearing facing the rotor core is connected to the outer peripheral wall of the rotating shaft through a welding fixing portion, and the second bearing is loosely matched with the rotating shaft.

10. The electric power steering motor according to claim 9, characterized in that: A second slot is further provided in the housing, the second slot is located on a side of the second bearing cavity facing the first bearing cavity, and the second slot is communicated with the second bearing cavity; The electric power steering motor also includes a third elastic portion, which is disposed in the second slot, is arranged around the rotating shaft, and is in contact with the second bearing, and is used to limit the axial displacement of the second bearing.

11. The electric power steering motor according to claim 1 or 2, characterized in that: Each of the core segments includes a plurality of rotor punchings, and the plurality of rotor punchings are stacked; the stator core includes a plurality of stator punchings, and the plurality of stator punchings are stacked; Among any two adjacent rotor punchings, one of the rotor punchings is provided with a first convex portion, and the other rotor punching is provided with a first concave portion, and the first convex portion is interference-fitted with the first concave portion; Among any two adjacent stator punching sheets, one of the stator punching sheets is provided with a second convex portion, and the other stator punching sheet is provided with a second concave portion, and the second convex portion and the second concave portion are interference fit.

12. The electric power steering motor according to claim 1 or 2, characterized in that: The stator core comprises a plurality of stator core blocks, and the plurality of stator core blocks are sequentially connected end to end around the axis of the shaft hole; The center of a circle corresponding to the outer circumferential wall of the stator core block and the center of a circle corresponding to the inner circumferential wall of the stator core block are collinear.

13. The electric power steering motor according to claim 1 or 2, characterized in that: The rotor core is further provided with a plurality of magnet slots, which are arranged at intervals along the circumferential direction of the rotating shaft, and the magnet slots are located between the shaft hole and the outer peripheral wall of the rotor core; The electric power steering motor further includes a plurality of permanent magnets, each of which is disposed in one of the magnet slots.

14. The electric power steering motor according to claim 13, characterized in that: The rotor core is further provided with a plurality of weight-reducing holes, which are arranged at intervals along the circumference of the rotating shaft, and the weight-reducing holes are located between the rotating shaft and the permanent magnets; The number of the weight-reducing holes is greater than or equal to the number of pole pairs of the electric power steering motor.

15. The electric power steering motor according to claim 1 or 2, characterized in that: At least a portion of the hole wall of the shaft hole is interference fit with the rotating shaft.

16. An electric power steering system, characterized in that: include: An electric power steering motor as claimed in any one of claims 1 to 15.

17. A vehicle, characterized in that: include: The electric power steering motor according to any one of claims 1 to 15; or The electric power steering system as claimed in claim 16.

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