Electric power steering motor, electric power steering system, and vehicle

Abstract

The present application provides an electric power steering motor, an electric power steering system, and a vehicle. The electric power steering motor comprises: a stator core; a rotor core, the rotor core comprising a plurality of core segments, the plurality of core segments being stacked, and the rotor core being provided with a shaft hole; a first bearing; and a second bearing, the first bearing and the second bearing both being sleeved on a 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 play δ of the four-point contact ball bearing, the minimum value lg of a gap between a cavity wall of an accommodating cavity and an 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 the following relationship: δ×(Lr+Ls)<2×lg×(R2-R1). The arrangement can enhance the overall deformation resistance of the motor, and is beneficial to improving the structural rigidity of the electric power steering motor.

Description

Electric power steering motor, electric power steering system and vehicle

[0001] The present application claims priority to the Chinese Patent Application No. 202411042990.5, filed on July 30, 2024, and titled "Electric Power Steering Motor, Electric Power Steering System and Vehicle", and to the Chinese Patent Application No. 202421837231.3, filed on July 30, 2024, and titled "Electric Power Steering Motor, Electric Power Steering System and Vehicle", the contents of both of which are incorporated herein by reference in their entirety. TECHNICAL FIELD

[0002] The present application relates to the technical field of electric machines, in particular to an electric power steering motor, an electric power steering system and a vehicle. BACKGROUND

[0003] In the related art, the electric machine of a new energy vehicle includes a stator core, a rotor core, a first bearing and a second bearing. The structure of the stator core, the rotor core, the first bearing and the second bearing is not reasonable, the vibration noise of the electric machine is large, which leads to a large noise when the vehicle is running, and seriously affects the driving experience of the user. TECHNICAL SOLUTION

[0004] The present application aims to at least solve one of the technical problems existing in the prior art or the related art.

[0005] To this end, a first aspect of the present application provides an electric power steering motor.

[0006] A second aspect of the present application provides an electric power steering system.

[0007] A third aspect of the present application provides a vehicle.

[0008] Therefore, the application provides an electric power assisted steering motor, which comprises a stator core, a rotor core, a rotating shaft, a first bearing, and a second bearing.

[0009] According to the electric power assisted steering motor provided in the application, the following additional technical features can be further provided.

[0010] In some embodiments, for example, the δ, lg, R1, R2, Ls and Lr satisfy 0 < (δ×(Lr+Ls)) / (2×lg×(R2-R1))≤0.8.

[0011] In some embodiments, for example, the electric power assisted steering motor further comprises a housing, wherein the housing is internally provided with a first bearing cavity and a second bearing cavity, the stator core, the rotor core, the rotating shaft, the first bearing and the second bearing are all arranged in the housing, the first bearing is arranged in the first bearing cavity, and the second bearing is arranged in the second bearing cavity.

[0012] In some embodiments, for example, the second bearing cavity is internally provided with a fixing protrusion, 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.

[0013] In some embodiments, for example, when one of the first bearing and the second bearing is a four-point contact ball bearing, the other one is also a four-point contact ball bearing.

[0014] In some embodiments, for example, the axial clearance of the second bearing is less than or equal to 0.1 mm.

[0015] In some embodiments, for example, along the axial direction of the rotating shaft, the minimum distance between the end faces of the second bearing and the rotor core, which are close to each other, is d, and 0.025≤(2×d) / (Lr+Ls)≤1.25.

[0016] In some embodiments, the housing further comprises a first clamping groove, the first clamping groove is located on a side of the second bearing cavity facing the first bearing cavity, and the first clamping groove is in communication with the second bearing cavity; the electric power steering motor further comprises a second elastic part, the second elastic part is arranged in the first clamping groove, the second elastic part surrounds the rotating shaft, and the second elastic part abuts against the second bearing, the second elastic part is used for limiting the axial displacement of the second bearing, and the second bearing is in interference fit with the rotating shaft.

[0017] In some embodiments, 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 part, and the second bearing is in clearance fit with the rotating shaft.

[0018] In some embodiments, the housing further comprises a second clamping groove, the second clamping groove is located on a side of the second bearing cavity facing the first bearing cavity, and the second clamping groove is in communication with the second bearing cavity; the electric power steering motor further comprises 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 for limiting the axial displacement of the second bearing.

[0019] In some embodiments, each of the core segments comprises a plurality of rotor laminations, the plurality of rotor laminations are stacked, the stator core comprises a plurality of stator laminations, and the plurality of stator laminations are stacked; in any two adjacent rotor laminations, one rotor lamination is provided with a first protrusion, and the other rotor lamination is provided with a first recess, and the first protrusion is in interference fit with the first recess; in any two adjacent stator laminations, one stator lamination is provided with a second protrusion, and the other stator lamination is provided with a second recess, and the second protrusion is in interference fit with the second recess.

[0020] In some embodiments, the stator core comprises a plurality of stator core blocks, and the plurality of stator core blocks are sequentially connected in a head-to-tail manner around the axis of the shaft hole; the center of the outer peripheral wall of the stator core block corresponds to the center of the inner peripheral wall of the stator core block.

[0021] In some embodiments, the rotor core further comprises a plurality of magnet grooves, the plurality of magnet grooves are arranged at intervals in the circumferential direction of the rotating shaft, and the magnet grooves are located between the shaft hole and the outer peripheral wall of the rotor core; the electric power steering motor further comprises a plurality of permanent magnets, and each of the permanent magnets is arranged in one of the magnet grooves.

[0022] In some embodiments, the rotor core further comprises a plurality of weight reduction holes, the plurality of weight reduction holes are arranged at intervals in the circumferential direction of the rotating shaft, and the weight reduction holes are located between the rotating shaft and the permanent magnets; the number of the weight reduction holes is greater than or equal to the number of pole pairs of the electric power steering motor.

[0023] In some embodiments, at least a part of the hole wall of the shaft hole is in interference fit with the rotating shaft.

[0024] A second aspect of the present application provides an electric power assisted steering system, comprising the electric power assisted steering motor as in the first aspect.

[0025] A third aspect of the present application provides a vehicle, comprising the electric power assisted steering motor as in the first aspect; or the electric power assisted steering system as in the second aspect.

[0026] Additional aspects and advantages of the present application will become apparent from the following description, or will be learned by practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0027] The above and / or additional aspects and advantages of the present application will become apparent and be readily appreciated from the following description, taken in conjunction with the accompanying drawings, in which:

[0028] FIG. 1 shows a first partial structural schematic diagram of an electric power assisted steering motor of one embodiment of the present application;

[0029] FIG. 2 shows an exploded view of the first partial structure of the electric power assisted steering motor of one embodiment of the present application;

[0030] FIG. 3 shows an exploded view of a second partial structure of the electric power assisted steering motor of one embodiment of the present application;

[0031] FIG. 4 shows an exploded view of a third partial structure of the electric power assisted steering motor of one embodiment of the present application;

[0032] FIG. 5 shows an exploded view of a fourth partial structure of the electric power assisted steering motor of one embodiment of the present application;

[0033] FIG. 6 shows a structural schematic diagram of the electric power assisted steering motor of the first embodiment of the present application;

[0034] FIG. 7 shows a partial structural schematic diagram of the electric power assisted steering motor of the first embodiment of the present application;

[0035] FIG. 8 shows a partial structural schematic diagram of the electric power assisted steering motor of the second embodiment of the present application;

[0036] FIG. 9 shows a partial structural schematic diagram of the electric power assisted steering motor of the third embodiment of the present application;

[0037] FIG. 10 shows a partial structural schematic diagram of a stator core of one embodiment of the present application;

[0038] FIG. 11 shows a partial structural schematic diagram of a rotor core of one embodiment of the present application;

[0039] FIG. 12 shows a structural schematic diagram of a second bearing of one embodiment of the present application;

[0040] Fig. 13 shows a data graph of the ratio of the 24th order noise of the motor of the application to the motor in the related art varying with X;

[0041] Fig. 14 shows a data graph of the axial force and cost of the second bearing of the application varying with V.

[0042] In the figures 1-14, the correspondence between the reference signs and the component names is as follows:

[0043] 10 electric power steering motor, 100 stator core, 110 accommodating cavity, 120 stator lamination, 130 second protrusion, 140 second recess, 150 stator core block, 152 outer peripheral wall of stator core block, 154 inner peripheral wall of stator core block, 200 rotor core, 210 core segment, 212 rotor lamination, 220 shaft hole, 230 first protrusion, 240 first recess, 250 magnet slot, 260 weight-reducing hole, 300 rotating shaft, 400 first bearing, 500 second bearing, 600 housing, 610 first bearing cavity, 620 second bearing cavity, 622 fixing protrusion, 630 first clamping groove, 640 second clamping groove, 650 machine shell, 660 end cover, 700 first elastic part, 800 second elastic part, 900 permanent magnet, 1000 third elastic part, 1100 welded fixing part. Embodiments of the application

[0044] In order to enable a more clear understanding of the above-mentioned objects, features and advantages of the application, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the embodiments of the application and the features in the embodiments can be combined with each other without conflict.

[0045] In the following description, a lot of specific details are set forth in order to give a thorough understanding of the application, however, the application can also be implemented in other ways different from those described herein, and therefore, the protection scope of the application is not limited by the specific embodiments disclosed below.

[0046] The electric power steering motor 10, the electric power steering system and the vehicle of some embodiments of the application are described below with reference to Figs. 1-14.

[0047] As shown in Figs. 1, 2, 3, 4, 5, 6 and 12, an electric power steering motor 10 according to some embodiments of the application comprises a stator core 100, a rotor core 200, a rotating shaft 300, a first bearing 400 and a second bearing 500.

[0048] The stator core 100 is provided with an accommodating cavity 110.

[0049] The rotor core 200 is arranged in the accommodating cavity 110.

[0050] The rotor core 200 comprises a plurality of core segments 210.

[0051] The plurality of core segments 210 are stacked.

[0052] Any two adjacent core segments 210 are arranged in a clockwise direction or in a counterclockwise direction.

[0053] The rotor core 200 is provided with a shaft hole 220.

[0054] The shaft hole 220 penetrates the plurality of core segments 210 in the axial direction of the rotor core 200.

[0055] The rotating shaft 300 is arranged in the shaft hole 220.

[0056] The first bearing 400 and the second bearing 500 are both arranged around the rotating shaft 300.

[0057] The rotor core 200 is located between the first bearing 400 and the second bearing 500.

[0058] At least one of the first bearing 400 and the second bearing 500 is a four-point contact ball bearing.

[0059] 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: δ×(Lr+Ls)<2×lg×(R2-R1).

[0060] The application provides an electric power steering motor 10 comprising a stator core 100, a rotor core 200, a rotating shaft 300, a first bearing 400, and a second bearing 500.

[0061] The rotor core 200 comprises a plurality of core segments 210 stacked in the axial direction of the rotor core 200. Any two adjacent core segments 210 are arranged in a clockwise direction or in a counterclockwise direction. That is, any two adjacent core segments 210 are arranged in a circumferential direction of the rotor core 200 to form a rotor skew field. The segmented and modularized arrangement of the rotor core 200 has the advantages of facilitating installation and maintenance, and a skew field can be formed between the plurality of core segments 210.

[0062] The arrangement of the arbitrary adjacent two core segments 210 in the clockwise direction or in the counterclockwise direction can reduce the cogging torque and torque ripple, thereby reducing the electromagnetic vibration. That is, by dividing the rotor core 200 into a plurality of core segments 210 and arranging the arbitrary adjacent two core segments 210 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 the cogging torque of the electric power steering motor 10 can be improved, and the vibration noise of the electric power steering motor 10 can be reduced.

[0063] Further, the rotor core 200 is provided with an axial hole 220 penetrating the plurality of core segments 210 in the axial direction of the rotor core 200, the rotating shaft 300 is arranged in the axial 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, and the second bearing 500 is located outside the rotor core 200. The rotor core 200 is located between the first bearing 400 and the second bearing 500.

[0064] 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. Alternatively, the second bearing 500 is a four-point contact ball bearing. Alternatively, the first bearing 400 is a four-point contact ball bearing, and the second bearing 500 is a four-point contact ball bearing.

[0065] The four-point contact ball bearing can enhance the overall deformation resistance of the electric power steering motor 10, improve the structural rigidity of the electric power steering motor 10, and reduce the axial displacement of the electric power steering motor 10 during operation. Thus, 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 is further reduced, and the use performance and market competitiveness of the electric power steering motor 10 are greatly improved.

[0066] Further, an axial play of the four-point contact ball bearing is denoted as δ, a minimum gap between the cavity wall of the accommodating cavity 110 and the outer peripheral wall of the rotor core 200 is denoted as lg, an inner diameter of the stator core 100 is denoted as R1, an outer diameter of the stator core 100 is denoted as R2, an axial length of the stator core 100 is denoted as Ls, and an axial length of the rotor core 200 is denoted as Lr, wherein δ, lg, R1, R2, Ls and Lr satisfy: δ×(Lr+Ls)<2×lg×(R2-R1). That is, the play of the four-point contact ball bearing, the fitting structure of the stator core 100 and the rotor core 200 are limited, which can enhance the overall deformation resistance of the electric power steering motor 10, is conducive to improving the structural rigidity of the electric power steering motor 10, can reduce the axial displacement of the electric power steering motor 10 during operation, so that the vibration performance of the electric power steering motor 10 during operation 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.

[0067] It can be understood that, when there is no load, the inner ring of the four-point contact ball bearing is fixed, and the outer ring of the four-point contact ball bearing is displaced from one extreme position to the other extreme position along the axial direction of the rotor core 200 relative to the fixed inner ring, and the displacement amount is denoted as the axial play of the four-point contact ball bearing. Alternatively, when there is no load, the outer ring of the four-point contact ball bearing is fixed, and the inner ring of the four-point contact ball bearing is displaced from one extreme position to the other extreme position along the axial direction of the rotor core 200 relative to the fixed outer ring, and the displacement amount is denoted as the axial play of the four-point contact ball bearing.

[0068] When the first bearing 400 and the second bearing 500 are both four-point contact ball bearings, that is, the axial two sides of the rotor core 200 are both provided with four-point contact ball bearings, so that the fitting area and the fitting angle of the first bearing 400, the second bearing 500 and the rotating shaft 300 are increased, the overall deformation resistance of the rotor can be further enhanced, the structural rigidity of the electric power steering motor 10 can be further improved, and the axial displacement of the electric power steering motor 10 during operation can be reduced, so that 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.

[0069] In some embodiments, for example, δ, lg, R1, R2, Ls and Lr satisfy: 0<(δ×(Lr+Ls)) / (2×lg×(R2-R1))≤0.8.

[0070] In this embodiment, the matching structure of the axial clearance δ of the four-point contact ball bearing, the minimum clearance lg of 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 is further defined.

[0071] Specifically, δ, lg, R1, R2, Ls and Lr satisfy: 0 < (δ x (Lr + Ls)) / (2 x lg x (R2 - R1)) ≤ 0.8. In order to enhance the overall deformation resistance of the electric power assisted steering motor 10, it is beneficial to improve the structural rigidity of the electric power assisted steering motor 10, which can reduce the axial displacement of the electric power assisted steering motor 10 during operation. In this way, the vibration performance of the electric power assisted steering motor 10 during operation is further improved, which can further reduce the vibration noise of the motor, greatly improving the use performance and market competitiveness of the motor.

[0072] Exemplarily, (δ x (Lr + Ls)) / (2 x lg x (R2 - R1)) = 0.1, (δ x (Lr + Ls)) / (2 x lg x (R2 - R1)) = 0.2, (δ x (Lr + Ls)) / (2 x lg x (R2 - R1)) = 0.3, (δ x (Lr + Ls)) / (2 x lg x (R2 - R1)) = 0.4, (δ x (Lr + Ls)) / (2 x lg x (R2 - R1)) = 0.5, (δ x (Lr + Ls)) / (2 x lg x (R2 - R1)) = 0.6 and (δ x (Lr + Ls)) / (2 x lg x (R2 - R1)) = 0.7, which are not listed one by one here.

[0073] In some embodiments, exemplarily, as shown in FIG. 2 and FIG. 6, the electric power assisted steering motor 10 further comprises a housing 600 and a first elastic part 700.

[0074] The first bearing cavity 610 and the second bearing cavity 620 are arranged in the housing 600.

[0075] The stator core 100, the rotor core 200, the rotating shaft 300, the first bearing 400 and the second bearing 500 are arranged in the housing 600.

[0076] The first bearing 400 is located in the first bearing cavity 610.

[0077] The second bearing 500 is located in the second bearing cavity 620.

[0078] The first elastic part 700 is arranged in the first bearing cavity 610.

[0079] The first elastic part 700 abuts between the side of the first bearing 400 away from the rotor core 200 and the cavity wall of the first bearing cavity 610.

[0080] The first elastic part 700 is used to apply an axial pre-tightening force to the first bearing 400.

[0081] The first bearing 400 is in interference fit with the rotating shaft 300.

[0082] In this embodiment, the electric power assisted steering motor 10 further comprises a housing 600 and a first elastic part 700.

[0083] 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, the housing 600 serves as a mounting carrier of 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 mounting and fixing the stator core 100, the rotor core 200, the rotating shaft 300, the first bearing 400 and the second bearing 500, so as to ensure the cooperation dimension of the stator core 100, the rotor core 200, the rotating shaft 300, the first bearing 400 and the second bearing 500.

[0084] The housing 600 is internally provided with a first bearing cavity 610 and a second bearing cavity 620, the first bearing cavity 610 is used to mount the first bearing 400, and the second bearing cavity 620 is used to mount the second bearing 500.

[0085] 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, the first elastic part 700 is located between the side of the first bearing 400 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 as to stably assemble the first bearing 400 on the rotating shaft 300.

[0086] It can be understood that after the electric power assisted 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, and the first elastic part 700 is extruded to apply an axial pre-tightening force to the first bearing 400, so as to ensure the structural rigidity of the electric power assisted steering motor 10, and facilitate to reduce the axial displacement amount of the electric power assisted steering motor 10 during operation.

[0087] It can be understood that the cavity wall of the first bearing cavity 610 has the function of limiting the first bearing 400, specifically, the cavity wall of the first bearing cavity 610 is used to limit the first bearing 400 in the radial direction of the rotating shaft 300.

[0088] In addition, the first bearing 400 and the rotating shaft 300 are in interference fit to limit the first bearing 400 in the axial and radial directions of the rotating shaft 300.

[0089] Exemplarily, the first elastic part 700 includes a wave pad, a spring, a torsional spring, a tension spring, and the like, which are not listed one by one here.

[0090] In some embodiments, exemplarily, as shown in FIG. 7, the second bearing cavity 620 is provided with a fixing protrusion 622.

[0091] The fixing protrusion 622 abuts against the outer peripheral wall of the second bearing 500.

[0092] The second bearing 500 is in interference fit with the rotating shaft 300.

[0093] In this embodiment, the cooperation structure of the housing 600 and the second bearing 500 is further defined.

[0094] Specifically, the second bearing cavity 620 is provided with the fixing protrusion 622, the fixing protrusion 622 abuts against the outer peripheral wall of the second bearing 500, and specifically, the fixing protrusion 622 is riveted to the outer side of the second bearing 500, and the second bearing 500 is in interference fit with the rotating shaft 300. The fixing protrusion 622 cooperates with the rotating shaft 300 to limit the second bearing 500 in the axial, radial, and circumferential directions of the rotating shaft 300. This improves the structural rigidity of the electric power steering motor 10, can reduce the axial displacement of the electric power steering motor 10 during operation, and can enhance the overall deformation resistance 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, which can further reduce the vibration noise of the electric power steering motor 10, and greatly improve the use performance and market competitiveness of the electric power steering motor 10.

[0095] Exemplarily, the number of the fixing protrusions 622 is multiple, and the multiple fixing protrusions 622 are arranged at intervals in the circumferential direction of the rotating shaft 300.

[0096] In some embodiments, exemplarily, 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.

[0097] In this embodiment, the types of the first bearing 400 and the second bearing 500 are further defined.

[0098] 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.

[0099] In 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.

[0100] In some embodiments, the axial clearance of the second bearing 500 is less than or equal to 0.1 mm.

[0101] In this embodiment, the axial clearance δ of the second bearing 500 is further limited to a range of values such that δ≤0.1 mm, so that the axial vibration of the electric power steering motor 10 can be further optimized, and the vibration noise of the electric power steering motor 10 can be further optimized.

[0102] In some embodiments, as shown in FIGS. 2 and 6, along the axial direction of the rotation shaft 300, the minimum distance between the end faces of the second bearing 500 and the rotor core 200 is d; wherein 0.025≤(2×d) / (Lr+Ls)≤1.25.

[0103] In this embodiment, the cooperation structure of the second bearing 500 and the rotor core 200 is further limited.

[0104] Along the axial direction of the rotation shaft 300, the minimum distance between the end faces of the second bearing 500 and the rotor core 200 is d. That is, along the axial direction of the rotation shaft 300, the end face of the second bearing 500 facing the rotor core 200 is a first end face, and the end face of the rotor core 200 facing the second bearing 500 is a second end face, and the minimum distance between the first end face and the second end face is d.

[0105] Wherein d, Lr and Ls satisfy 0.025≤(2×d) / (Lr+Ls)≤1.25. The smaller the distance d is, the greater the axial force on the second bearing 500 caused by the magnetic leakage will be. The greater the distance d is, the greater the production cost will be. That is, d, Lr and Ls satisfy 0.025≤(2×d) / (Lr+Ls)≤1.25, which takes into account 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, and the cost performance is the highest.

[0106] For example, (2×d) / (Lr+Ls)=0.05, (2×d) / (Lr+Ls)=0.075, (2×d) / (Lr+Ls)=0.1, and the like, which are not listed one by one.

[0107] In some embodiments, as shown in FIG. 8, the housing 600 further comprises a first clamping groove 630.

[0108] The first clamping groove 630 is located on the side of the second bearing cavity 620 facing the first bearing cavity 610.

[0109] And the first clamping groove 630 communicates with the second bearing cavity 620.

[0110] The electric power assisted steering motor 10 further comprises a second elastic part 800.

[0111] The second elastic part 800 is arranged in the first clamping groove 630.

[0112] The second elastic part 800 surrounds the rotating shaft 300.

[0113] The second elastic part 800 abuts against the second bearing 500.

[0114] The second elastic part 800 is used to limit the axial displacement of the second bearing 500.

[0115] The second bearing 500 is interference-fitted with the rotating shaft 300.

[0116] In this embodiment, the fitting structure of the rotating shaft 300 and the second bearing 500 is further defined.

[0117] The housing 600 further comprises a first clamping groove 630, which is located on the side of the second bearing cavity 620 facing the first bearing cavity 610 and is in communication with the second bearing cavity 620.

[0118] The electric power assisted steering motor 10 further comprises a second elastic part 800, and the first clamping groove 630 is used to install and fix the second elastic part 800. The second elastic part 800 is arranged in the first clamping groove 630, surrounds the rotating shaft 300, and abuts against the second bearing 500. The second elastic part 800 is used to limit the second bearing 500 along the axial direction of the rotating shaft 300, so as to ensure the fitting size of the second bearing 500 and the rotating shaft 300. This is conducive to improving the stability and reliability of the assembly of the rotating shaft 300 and the second bearing 500, thereby enhancing the overall deformation resistance of the electric power assisted steering motor 10 and reducing the friction torque of the electric power assisted steering motor 10.

[0119] The second bearing 500 is interference-fitted with the rotating shaft 300. The rotating shaft 300 and the second elastic part 800 are matched to stably assemble the second bearing 500 and the rotating shaft 300 together.

[0120] The rotating shaft 300 and the second elastic part 800 are matched to limit the second bearing 500 along the axial direction, the radial direction, and the circumferential direction of the rotating shaft 300. This improves the structural rigidity of the electric power assisted steering motor 10, reduces the axial displacement of the electric power assisted steering motor 10 during operation, and enhances the overall deformation resistance of the electric power assisted steering motor 10. 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 is further reduced, and the use performance and market competitiveness of the electric power assisted steering motor 10 are greatly improved.

[0121] In addition, the second bearing 500 is a four-point contact ball bearing, and the second bearing 500 is interference-fitted with the rotating shaft 300, and the second elastic part 800 limits the axial displacement of the second bearing 500. This arrangement can reduce the influence on the radial play of the second bearing 500, and ensure the radial play of the second bearing 500, so as to facilitate the reduction of the friction torque of the electric power steering motor 10 during operation. That is, this arrangement takes into account the reduction of the vibration noise of the electric power steering motor 10 and the reduction of the friction torque of the electric power steering motor 10, and improves the use performance and market competitiveness of the product.

[0122] Exemplarily, the second elastic part 800 includes a spring, a torsion spring, a tension spring, and the like, which are not listed one by one here.

[0123] It can be understood that, under 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 along the radial direction of the rotor core 200 from one extreme position to the other extreme position is recorded as the radial play of the second bearing 500.

[0124] In some embodiments, exemplarily, as shown in FIG. 9, the end surface of the second bearing 500 facing the rotor core 200 is connected to the outer peripheral wall of the rotating shaft 300 through the welding fixing part 1100.

[0125] The second bearing 500 is clearance-fitted with the rotating shaft 300.

[0126] In this embodiment, the fitting structure of the rotating shaft 300 and the second bearing 500 is further limited.

[0127] Specifically, the second bearing 500 is clearance-fitted with the rotating shaft 300, and the end surface of the second bearing 500 facing the rotor core 200 is connected to the outer peripheral wall of the rotating shaft 300 through the welding fixing part 1100. That is, the welding fixing part 1100 stably assembles the second bearing 500 and the rotating shaft 300 together.

[0128] The welding fixing part 1100 cooperates with the rotating shaft 300 to limit the second bearing 500 in the axial direction, the radial direction, and the circumferential direction of the rotating shaft 300. This improves the structural rigidity of the electric power steering motor 10, can reduce the axial displacement of the electric power steering motor 10 during operation, and can enhance the overall deformation resistance 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 use performance and market competitiveness of the electric power steering motor 10 are greatly improved.

[0129] 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 by the welding fixing part 1100. This arrangement can reduce the influence on the radial clearance of the second bearing 500 and ensure the radial clearance of the second bearing 500, so as to be conducive to reducing the friction torque of the electric power steering motor 10 during operation. That is, this arrangement takes into account both reducing the vibration noise of the electric power steering motor 10 and reducing the friction torque of the electric power steering motor 10, thereby improving the use performance and market competitiveness of the product.

[0130] 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 along the radial direction of the rotor core 200 from one extreme position to another extreme position is recorded as the radial clearance of the second bearing 500.

[0131] In some embodiments, for example, as shown in FIG. 9, the housing 600 is further provided with a second clamping groove 640.

[0132] The second clamping groove 640 is located on the side of the second bearing cavity 620 facing the first bearing cavity 610, and the second clamping groove 640 communicates with the second bearing cavity 620.

[0133] The electric power steering motor 10 further comprises a third elastic part 1000.

[0134] The third elastic part 1000 is arranged in the second clamping groove 640.

[0135] The third elastic part 1000 surrounds the rotating shaft 300.

[0136] And the third elastic part 1000 abuts against the second bearing 500.

[0137] The third elastic part 1000 is used to limit the axial displacement of the second bearing 500.

[0138] In this embodiment, the cooperation structure of the housing 600 and the second bearing 500 is further limited.

[0139] The housing 600 is further provided with a second clamping groove 640, and the second clamping groove 640 is located on the side of the second bearing cavity 620 facing the first bearing cavity 610, and the second clamping groove 640 communicates with the second bearing cavity 620.

[0140] The electric power assisted steering motor 10 further comprises a third elastic part 1000, and the second clamping groove 640 is used for mounting and fixing the third elastic part 1000. The third elastic part 1000 is arranged at the second clamping groove 640, the third elastic part 1000 surrounds the rotating shaft 300, and the third elastic part 1000 abuts against the second bearing 500. The third elastic part 1000 is used for limiting the second bearing 500 in the axial direction of the rotating shaft 300, so as to ensure the matching size of the second bearing 500 and the rotating shaft 300. This is favorable for improving the stability and reliability of the assembly of the rotating shaft 300 and the second bearing 500, enhancing the overall deformation resistance of the electric power assisted steering motor 10, and reducing the friction torque of the electric power assisted steering motor 10.

[0141] The welding fixing part 1100 and the third elastic part 1000 cooperate to reduce the vibration noise of the electric power assisted steering motor 10, ensure the radial clearance of the second bearing 500, enhance the deformation resistance of the electric power assisted steering motor 10, and reduce the friction torque of the electric power assisted steering motor 10. That is to say, this arrangement takes into account the reduction of the vibration noise and the friction torque of the electric power assisted steering motor 10, and improves the use performance and market competitiveness of the product.

[0142] In some embodiments, each core segment 210 includes a plurality of rotor laminations 212, as shown in FIG. 11.

[0143] The plurality of rotor laminations 212 are stacked.

[0144] As shown in FIG. 10, the stator core 100 includes a plurality of stator laminations 120.

[0145] The plurality of stator laminations 120 are stacked.

[0146] In any two adjacent rotor laminations 212, one rotor lamination 212 is provided with a first protrusion 230, and the other rotor lamination 212 is provided with a first recess 240.

[0147] The first protrusion 230 and the first recess 240 are in interference fit.

[0148] In any two adjacent stator laminations 120, one stator lamination 120 is provided with a second protrusion 130, and the other stator lamination 120 is provided with a second recess 140.

[0149] The second protrusion 130 and the second recess 140 are in interference fit.

[0150] In this embodiment, each core segment 210 includes a plurality of rotor laminations 212, and the plurality of rotor laminations 212 are stacked.

[0151] In any two adjacent rotor laminations 212, one of the rotor laminations 212 is provided with a first protrusion 230, and the other of the rotor laminations 212 is provided with a first recess 240, and the first protrusion 230 is in interference fit with the first recess 240.

[0152] Specifically, the first side axial end face of each rotor lamination 212 is provided with the first recess 240, and the second side axial end face of each rotor lamination 212 is provided with the first protrusion 230. That is, along the axial direction of the rotor core 200, the rotor lamination 212 has oppositely arranged first and second end faces, the first end face is provided with the first recess 240, and the second end face is provided with the first protrusion 230.

[0153] When the two adjacent rotor laminations 212 are assembled, the first protrusion 230 is inserted into the first recess 240, and the first protrusion 230 and the first recess 240 are in interference fit, so as to achieve the assembly of the two rotor laminations 212.

[0154] The first protrusion 230 and the first recess 240 are in interference fit, so as to increase the contact area and the contact angle of the two adjacent rotor laminations 212, which is beneficial to improve the stability and reliability of the assembly of the two adjacent rotor laminations 212 in the axial direction of the rotor core 200, prevent the rotor lamination 212 from being scattered, and ensure the structural rigidity of the assembly of the rotor core 200.

[0155] In this embodiment, the stator core 100 includes a plurality of stator laminations 120, and the plurality of stator laminations 120 are stacked.

[0156] In any two adjacent stator laminations 120, one of the stator laminations 120 is provided with a second protrusion 130, and the other of the stator laminations 120 is provided with a second recess 140, and the second protrusion 130 is in interference fit with the second recess 140.

[0157] Specifically, the first side axial end face of each stator lamination 120 is provided with the second recess 140, and the second side axial end face of each stator lamination 120 is provided with the second protrusion 130. That is, along the axial direction of the stator core 100, the stator lamination 120 has oppositely arranged first and second end faces, the first end face is provided with the second recess 140, and the second end face is provided with the second protrusion 130.

[0158] When the two adjacent stator laminations 120 are assembled, the second protrusion 130 is inserted into the second recess 140, and the second protrusion 130 and the second recess 140 are in interference fit, so as to achieve the assembly of the two stator laminations 120.

[0159] The second protrusion 130 and the second groove 140 are matched to increase the contact area and the contact angle of the two adjacent stator laminations 120, which is beneficial to improve the stability and reliability of the assembly of the two adjacent stator laminations 120 in the axial direction of the stator core 100, prevent the stator laminations 120 from being scattered, and ensure the structural rigidity of the assembly of the stator core 100.

[0160] In some embodiments, as shown in FIG. 3, the stator core 100 includes a plurality of stator core blocks 150.

[0161] The plurality of stator core blocks 150 are sequentially connected end to end around the axis of the shaft hole 220.

[0162] 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.

[0163] In this embodiment, the stator core 100 includes a plurality of stator core blocks 150, and the plurality of stator core blocks 150 are sequentially connected end to end around the axis of the shaft hole 220.

[0164] 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.

[0165] That is, the stator core 100 is a segmented core structure, and the plurality of stator core blocks 150 are sequentially connected end to end around the axis of the shaft hole 220. This arrangement can greatly improve the slot fill rate 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.

[0166] In some embodiments, as shown in FIGS. 2, 3, 4, 5, and 6, the rotor core 200 is further provided with a plurality of magnet grooves 250.

[0167] The plurality of magnet grooves 250 are arranged in a circumferential direction of the rotation shaft 300.

[0168] The magnet grooves 250 are located between the shaft hole 220 and the outer peripheral wall of the rotor core 200.

[0169] The electric power steering motor 10 further includes a plurality of permanent magnets 900.

[0170] Each permanent magnet 900 is arranged in one magnet groove 250.

[0171] In this embodiment, the specific structure of the electric power steering motor 10 is further limited.

[0172] The 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 grooves 250, and the plurality of magnet grooves 250 are arranged in a circumferential direction of the rotation shaft 300.

[0173] The electric power steering motor 10 further comprises a plurality of permanent magnets 900, each of which is arranged in a magnet slot 250. That is, the plurality of permanent magnets 900 are arranged in the rotor core 200 and are arranged at intervals along the circumferential direction of the rotation shaft 300. The permanent magnets 900 are located between the shaft hole 220 and the outer circumferential wall of the rotor core 200.

[0174] In some embodiments, the rotor core 200 is further provided with a plurality of lightening holes 260, as shown in Figs. 2, 3, 4, 5 and 6.

[0175] The plurality of lightening holes 260 are arranged at intervals along the circumferential direction of the rotation shaft 300.

[0176] The lightening holes 260 are located between the rotation shaft 300 and the permanent magnets 900.

[0177] The number of the lightening holes 260 is greater than or equal to the number of pole pairs of the electric power steering motor 10.

[0178] 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 lightening holes 260 arranged at intervals along the circumferential direction of the rotation shaft 300, and the lightening holes 260 are located between the rotation shaft 300 and the permanent magnets 900. The lightening holes 260 have the effect of reducing the overall weight of the electric power steering motor 10.

[0179] In addition, any two adjacent core segments 210 are arranged at intervals in the clockwise direction or in the counterclockwise direction, that is, any two adjacent core segments 210 are arranged at intervals in the circumferential direction of the rotor core 200 to form a rotor skew pole. The lightening holes 260 can be used as a positioning basis to assemble the rotor core 200, thereby providing reliable structural support to ensure the formation of the rotor skew pole.

[0180] Further, the number of the lightening holes 260 is greater than or equal to the number of pole pairs of the electric power steering motor 10, and the plurality of lightening holes 260 are arranged at intervals along the circumferential direction of the rotation shaft 300. In this way, the plurality of core segments 210 can be positioned from multiple directions and at multiple angles when the rotor core 200 is assembled, thereby ensuring the fitting accuracy of the plurality of core segments 210.

[0181] For example, the number of the lightening holes 260 is equal to the number of pole pairs of the electric power steering motor 10.

[0182] For example, the lightening holes 260 are arranged on the magnetic pole center line and / or the inter-pole center line of the rotor core 200. In this way, the overall weight of the electric power steering motor 10 can be reduced without affecting the use performance of the electric power steering motor 10.

[0183] In some embodiments, at least a portion of the hole wall of the shaft hole 220 is in interference fit with the rotating shaft 300.

[0184] In this embodiment, the fitting structure of the rotor core 200 and the rotating shaft 300 is defined.

[0185] At least a portion of the hole wall of the shaft hole 220 is in interference fit with the rotating shaft 300. That is, a portion of the hole wall of the shaft hole 220 is in interference fit with the rotating shaft 300. Alternatively, the whole hole wall of the shaft hole 220 is in interference fit with the rotating shaft 300.

[0186] This arrangement can ensure the fitting structure of the rotating shaft 300 and the rotor core 200, and avoid the separation of the rotating shaft 300 and the rotor core 200.

[0187] When a portion of the hole wall of the shaft hole 220 is in interference fit with the rotating shaft 300, the contact area of the shaft hole 220 and the rotating shaft 300 can be reduced. That is, while the use requirement of the interference fit of the rotating shaft 300 and the shaft hole 220 is ensured, the radial force caused by the interference fit of the rotating shaft 300 and the shaft hole 220 can be reduced due to the reduction of the contact area of the shaft hole 220 and the rotating shaft 300, the influence of the radial force on the binding force between the rotor laminations 212 of the rotor core 200 can be reduced, the probability of the deformation of the rotor laminations 212 of the rotor core 200 can be reduced, and the probability of the loosening of the rotor laminations 212 of the rotor core 200 can be further reduced.

[0188] For example, the hole wall of the shaft hole 220 is a convex-concave wall, the convex part of the convex-concave wall is in interference fit with the rotating shaft 300, and the concave part of the convex-concave wall is arranged separately from the rotating shaft 300. The convex part and the concave part of the convex-concave wall are arranged alternately, and both the convex part and the concave part extend along the axial direction of the rotating shaft 300.

[0189] According to another embodiment of the present application, an electric power assisted steering system comprises the electric power assisted steering motor 10 of any of the above embodiments.

[0190] The electric power assisted steering system provided by the present application has all the advantages of the electric power assisted steering motor 10 described above, which will not be repeated here.

[0191] According to another embodiment of the present application, a vehicle comprises the electric power assisted steering motor 10 of any of the above embodiments or the electric power assisted steering system of any of the above embodiments.

[0192] The vehicle provided by the present application has all the advantages of the electric power assisted steering motor 10 or the electric power assisted steering system described above, which will not be repeated here.

[0193] It should be noted that the vehicle can be a new energy vehicle. The new energy vehicle includes a pure electric vehicle, a range-extended electric vehicle, a hybrid electric vehicle, a fuel cell electric vehicle, a hydrogen engine vehicle, and the like.

[0194] The vehicle can also be a fuel vehicle and a hybrid electric vehicle.

[0195] Exemplarily, by arranging the four-point contact ball bearing, the overall deformation resistance of the electric power steering motor 10 can be enhanced, the structural rigidity of the electric power steering motor 10 can be improved, the axial displacement of the electric power steering motor 10 during operation can be reduced, the vibration performance of the electric power steering motor 10 during operation can be further improved, the vibration noise of the electric power steering motor 10 can be further reduced, and the use performance and market competitiveness of the electric power steering motor 10 can be greatly improved.

[0196] Exemplarily, the electric power steering motor 10 includes a stator core 100 and a rotor core 200. The stator core 100 is provided with an accommodating cavity 110 at an 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, the plurality of core segments 210 are stacked, any two adjacent core segments 210 are arranged in a clockwise direction or in a counterclockwise direction, the rotor core 200 is provided with a shaft hole 220, and the shaft hole 220 penetrates the plurality of core segments 210 in an axial direction of the rotor core 200.

[0197] 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 arranged in the shaft hole 220.

[0198] The first bearing 400 and the second bearing 500 are both arranged on the rotating shaft 300, and the rotor core 200 is located between the first bearing 400 and the second bearing 500.

[0199] At least one of the first bearing 400 and the second bearing 500 is a four-point contact ball bearing.

[0200] 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.

[0201] Each core segment 210 includes a plurality of stacked rotor laminations 212, and the rotor core 200 is provided with a connecting structure, and any two adjacent rotor laminations 212 are connected through the connecting structure.

[0202] The stator core 100 comprises a plurality of stator core blocks 150, which are assembled into the stator core 100 by welding, and the outer edge and the inner edge of the stator core block 150 are two concentric arcs.

[0203] The stator core 100 comprises a plurality of stacked stator laminations 120, and the stator core 100 is provided with a connecting structure similar to the rotor core 200.

[0204] The connecting structure comprises a convex part and a groove. In any two adjacent rotor laminations 212, one rotor lamination 212 is provided with a first convex part 230, and the other rotor lamination 212 is provided with a first groove 240, and the first convex part 230 and the first groove 240 are in interference fit; in any two adjacent stator laminations 120, one stator lamination 120 is provided with a second convex part 130, and the other stator lamination 120 is provided with a second groove 140, and the second convex part 130 and the second groove 140 are in interference fit.

[0205] The electric power assisted steering motor 10 further comprises a plurality of permanent magnets 900, which are arranged on the core segment 210 and are arranged along the circumferential direction of the shaft hole 220. In 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.

[0206] The rotor core 200 is provided with a plurality of weight reduction holes 260, which are arranged 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 assisted steering motor 10.

[0207] At least a part of the hole wall of the shaft hole 220 is in interference fit with the rotating shaft 300.

[0208] The electric power assisted steering motor 10 further comprises a first elastic part 700, which 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, and the first elastic part 700 is used to apply an axial pre-tightening force to the first bearing 400.

[0209] The second bearing 500 is riveted and fixed in the second bearing cavity 620 through the fixed protrusion 622 of the second bearing cavity 620. In 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 is d; wherein 0.025≤(2×d) / (Lr+Ls)≤1.25.

[0210] The axial play δ of the second bearing 500 is less than or equal to 0.1mm.

[0211] The electric power assisted steering motor 10 comprises a stator core 100, the stator core 100 is composed of a plurality of stator core blocks 150 which are circularly assembled, the stator core blocks 150 are composed of a plurality of stator core sheets 120 which are stacked; a rotor core 200, the rotor core 200 comprises a plurality of core segments 210 which are stacked, any two adjacent core segments 210 are arranged in a clockwise direction or in a counterclockwise direction, the rotor core 200 is provided with a shaft hole 220; a rotating shaft 300, the rotating shaft 300 is arranged in 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, the first bearing 400 and the second bearing 500 are both 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 a first elastic part 700 and the rotor core 200, the first elastic part 700 is used for applying an axial pre-tightening force to the first bearing 400, an axial clearance δ of the second bearing 500 is less than or equal to 0.1mm, and satisfies 0< (δ×(Lr+Ls)) / (2×lg×(R2-R1))≤0.8.

[0212] The four-point contact ball bearing can enhance the overall deformation resistance of the electric power assisted steering motor 10, is conducive to improving the structural rigidity of the electric power assisted steering motor 10, can reduce the axial displacement of the electric power assisted steering motor 10 when working, so that the vibration performance of the electric power assisted steering motor 10 when running is further improved, the vibration noise of the electric power assisted steering motor 10 can be further reduced, and the use performance and market competitiveness of the electric power assisted steering motor 10 are greatly improved.

[0213] The electric power assisted steering motor 10 comprises 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 comprises a plurality of core segments 210 which are stacked in the axial direction of the rotor core 200, and any two adjacent core segments 210 are arranged in a clockwise direction or in a counterclockwise direction. This setting can reduce the cogging torque and torque ripple, thereby reducing electromagnetic vibration. In 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, so that the probability of extruding the permanent magnet 900 and causing damage to the permanent magnet 900 can be reduced.

[0214] 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 conducive 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 capability of the rotor core 200, the plurality of permanent magnets 900, the rotating shaft 300, the first bearing 400, and the second bearing 500, so as to reduce the axial displacement of the electric power steering motor 10 during operation.

[0215] At least one of the first bearing 400 and the second bearing 500 is a four-point contact ball bearing. The first bearing 400 and the second bearing 500 are both sleeved on the rotating shaft 300. 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, and the axial clearance δ of the four-point contact ball bearing is less than or equal to 0.1 mm. As shown in FIG. 13, let (δ×(Lr+Ls)) / (2×lg×(R2-R1)) be X, X changes, and take the 12-slot 8-pole permanent magnet motor as an example. The number of pole pairs p = 4. FIG. 13 shows the simulation results of the 24th order noise under different X. Lp is the unit value, and Lp is the ratio of the 24th order noise under different X to the 24th order noise of the motor in the related art. Within the range of 0 < X ≤ 0.8, the 24th order noise of the motor is better, and the cost performance is the highest.

[0216] The electric power steering motor 10 further comprises a first elastic portion 700 sleeved on the rotating shaft 300, and the first bearing 400 is located between the first elastic portion 700 and the rotor core 200, and the first elastic portion 700 is used to apply an axial pre-tightening force to the first bearing 400. The second bearing 500 is fixed in the second bearing cavity 620 by riveting the 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 is d; wherein 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 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, and FIG. 14 shows the changes of the axial force and the cost of the second bearing 500 under different V. The vertical coordinate Y is the unit value, and Y is the ratio of the axial force or the cost under different V to the axial force or the cost of the motor in the related art. Within 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.

[0217] Exemplarily, as shown in FIG. 6, the shell 600 comprises a casing 650 and an end cover 660.

[0218] 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. Alternatively, the second bearing 500 is a four-point contact ball bearing. Alternatively, the first bearing 400 is a four-point contact ball bearing, and the second bearing 500 is a four-point contact ball bearing.

[0219] The axial play of the four-point contact ball bearing is denoted as δ, the minimum gap between the cavity wall of the accommodating 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, 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, wherein δ, lg, R1, R2, Ls and Lr satisfy: δ×(Lr+Ls)<2×lg×(R2-R1). That is, the play of the four-point contact ball bearing, the matching structure of the stator core 100 and the rotor core 200 are limited, which can enhance the overall deformation resistance of the electric power steering motor 10, is conducive to improving the structural rigidity of the electric power steering motor 10, can reduce the axial displacement of the electric power steering motor 10 during operation, so that the vibration performance of the electric power steering motor 10 during operation is further improved, the vibration noise of the motor is further reduced, and the use performance and market competitiveness of the motor are greatly improved.

[0220] It can be understood that, under 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 the other extreme position is denoted as the axial play of the four-point contact ball bearing. Alternatively, under 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 the other extreme position is denoted as the axial play of the four-point contact ball bearing.

[0221] Exemplarily, δ, lg, R1, R2, Ls and Lr satisfy: 0<(δ×(Lr+Ls)) / (2×lg×( R2-R1))≤0.8.

[0222] In the present application, the term "a plurality of" refers to two or more, unless otherwise explicitly limited. The terms "mounting", "connecting", "connection", "fixing" and the like should be understood in a broad sense, for example, "connection" can be fixed connection, or detachable connection, or integrally connected; "connection" can be direct connection, or indirect connection through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0223] In the description of the application, the terms "one embodiment", "some embodiments”, "certain embodiments”, etc. do not necessarily refer to the same embodiment or example, though they can. Furthermore, these terms can refer to one or more embodiments or examples. The only sure way to determine the patent scope of an application making reference to "one embodiment” or other such terminological misnomer is to identify the claims in the application because claims define the patentable subject matter.

Claims

1. An electric power assisted steering motor wherein, The motor comprises: a stator core provided with a receiving cavity; a rotor core provided in the receiving cavity, the rotor core comprising a plurality of core segments, the plurality of core segments being stacked, any two adjacent core segments being arranged in a clockwise direction or in an anticlockwise direction, the rotor core being provided with a shaft hole penetrating through the plurality of core segments in an axial direction of the rotor core; a rotating shaft penetrating through the shaft hole; a first bearing; a second bearing, 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, at least one of the first bearing and the second bearing being a four-point contact ball bearing; an axial clearance δ of the four-point contact ball bearing, a minimum gap lg between a cavity wall of the receiving cavity and an outer peripheral wall of the rotor core, an inner diameter R1 of the stator core, an outer diameter R2 of the stator core, an axial length Ls of the stator core and an axial length Lr of the rotor core satisfying: δ×(Lr+Ls)<2×lg×(R2-R1).

2. The electric power assisted steering motor of claim 1 wherein, δ, lg, R1, R2, Ls and Lr satisfy: 0<(δ×(Lr+Ls)) / (2×lg×(R2-R1))≤0.

8.

3. The electric power assisted steering motor of claim 1 or 2, wherein, The motor further comprises: a housing, the housing being provided with a first bearing cavity and a second bearing cavity, the stator core, the rotor core, the rotating shaft, the first bearing and the second bearing being provided in the housing, the first bearing being located in the first bearing cavity, the second bearing being located in the second bearing cavity; a first elastic part provided in the first bearing cavity, the first elastic part 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 part being used for applying an axial pre-tightening force to the first bearing; wherein the first bearing is in interference fit with the rotating shaft.

4. The electric power assisted steering motor of claim 3 wherein, The second bearing cavity is provided with a fixing protrusion, the fixing protrusion abutting with an outer peripheral wall of the second bearing, and the second bearing is in interference fit with the rotating shaft.

5. The electric power assisted steering motor of claim 4 wherein, 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 assisted steering motor of claim 5 wherein, An axial clearance of the second bearing is less than or equal to 0.1 mm.

7. The electric power assisted steering motor of any one of claims 4 to 6 wherein, In an axial direction of the rotating shaft, a minimum distance d between end faces of the second bearing and the rotor core close to each other; wherein 0.025≤(2×d) / (Lr+Ls)≤1.

25.

8. The electric power assisted steering motor of claim 3 wherein, The housing is further provided with a first clamping groove, the first clamping groove being located on a side of the second bearing cavity facing the first bearing cavity, and the first clamping groove being in communication with the second bearing cavity; The electric power assisted steering motor further comprises a second elastic part, the second elastic part being provided in the first clamping groove, the second elastic part being arranged around the rotating shaft, and the second elastic part abutting with the second bearing, the second elastic part being used for limiting an axial displacement of the second bearing, and the second bearing is in interference fit with the rotating shaft.

9. The electric power assisted steering motor of claim 3 wherein, An end face of the second bearing facing the rotor core is connected with an outer peripheral wall of the rotating shaft through a welding fixing part, and the second bearing is in clearance fit with the rotating shaft.

10. The electric power assisted steering motor of claim 9 wherein, The shell is further provided with a second clamping groove, which is located on the side of the second bearing cavity facing the first bearing cavity and communicates with the second bearing cavity; The electric power assisted steering motor further comprises a third elastic part, which is arranged in the second clamping groove, surrounds the rotating shaft, and abuts against the second bearing, and is used for limiting the axial displacement of the second bearing.

11. The electric power assisted steering motor of any one of claims 1 to 10, wherein, Each of the core segments comprises a plurality of rotor laminations stacked together, and the stator core comprises a plurality of stator laminations stacked together; In any two adjacent rotor laminations, one rotor lamination is provided with a first protrusion, and the other rotor lamination is provided with a first recess, and the first protrusion and the first recess are in interference fit; In any two adjacent stator laminations, one stator lamination is provided with a second protrusion, and the other stator lamination is provided with a second recess, and the second protrusion and the second recess are in interference fit.

12. The electric power assisted steering motor of any one of claims 1 to 11, wherein, The stator core comprises a plurality of stator core blocks connected end to end in sequence around the axis of the shaft hole. The center of the outer peripheral wall of the stator core block corresponds to the center of the inner peripheral wall of the stator core block.

13. The electric power assisted steering motor of any one of claims 1 to 12, wherein, The rotor core is further provided with a plurality of magnet grooves, which are arranged in the circumferential direction of the rotating shaft and located between the shaft hole and the outer peripheral wall of the rotor core. The electric power assisted steering motor further comprises a plurality of permanent magnets, each of which is arranged in one of the magnet grooves.

14. The electric power assisted steering motor of claim 13 wherein, The rotor core is further provided with a plurality of weight reduction holes, which are arranged in the circumferential direction of the rotating shaft and 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 assisted steering motor.

15. The electric power assisted steering motor of any one of claims 1 to 14, wherein, At least a part of the hole wall of the shaft hole is in interference fit with the rotating shaft.

16. An electric power assisted steering system wherein, The electric power assisted steering motor comprises: The electric power assisted steering motor according to any one of claims 1 to 15.

17. A vehicle, wherein, The electric power assisted steering motor comprises: The electric power assisted steering motor according to any one of claims 1 to 15; Or The electric power assisted steering system according to claim 16.

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