Stator punching sheet, stator comprising stator punching sheet, and motor

Abstract

The stator punching sheet comprises an annular yoke portion, a plurality of tooth portions are evenly distributed on the inner side of the yoke portion in the circumferential direction, three grooves are formed in the tooth crown end face of the stator punching sheet at equal intervals in the circumferential direction, the cross section of each groove is in an arc shape, and the axial direction of each groove corresponds to the axial direction of the yoke portion; due to the existence of the grooves, the width of the air gap corresponding to the partial area of the end face of the tooth crown can be increased under the condition that the width of the air gap between the stator and the rotor is kept small, and the width of the air gap between the stator and the rotor can be non-uniformly distributed in the circumferential direction under the condition that the stator and the rotor are kept coaxial. The stator punching sheet structure is simple in structure, facilitates reduction of higher harmonics, not only can reduce no-load noise of a motor, but also can optimize load noise, can effectively solve the problem that the noise of the motor is difficult to reduce through an existing stator punching sheet structure, can improve the overall performance of the motor, reduces the noise level, and has a good application prospect.

Description

Technical Field

[0001] The present invention belongs to the technical field of salient-pole stator cores of motors, and particularly relates to a stator punching sheet, as well as a stator and a motor having the stator punching sheet. Background Art

[0002] A motor mainly includes a stator and a rotor. The stator usually includes a stator core, a stator winding, and a stator frame. The stator core is usually stacked by stator punching sheets (silicon steel sheets with high magnetic permeability). As shown in the Figure 1 figure, the stator punching sheet includes an annular yoke portion 1 and a plurality of tooth portions 2 connected to the yoke portion. The tooth portions are circumferentially distributed inside the yoke portion and extend radially. The tooth portion includes a tooth body 3 connected to the yoke portion and a tooth crown 4 connected to the inner end of the tooth body. The circumferential dimension of the tooth crown is larger than that of the tooth body. Tooth slots 5 are formed between adjacent tooth bodies, and notch openings 6 are formed between adjacent tooth crowns for winding coils to be embedded. The rotor is usually coaxially arranged inside the stator punching sheet. There is a certain air gap between the inner circular surface formed by the end face of the tooth crown of the stator punching sheet and the outer circular surface of the rotor for the rotor and the stator to rotate relative to each other.

[0003] To reduce the magnetic resistance, reduce the loss and leakage magnetic flux when the magnetic field passes through the air gap, so as to improve the motor efficiency, enhance the performance, and reduce the size. Currently, the air gap between the rotor and the stator in a motor is generally small. However, if the air gap is too small, it may cause magnetic saturation between the stator and the rotor, thereby increasing the non-linearity of the electromagnetic force. This non-linear electromagnetic force will generate more high-order harmonics, resulting in vibration and noise of the motor. At present, as one of the core components of new energy vehicles, the noise of the motor is also a key factor affecting the comfort of new energy vehicles. Therefore, it is necessary to optimize the design of the motor and reduce its noise on the premise of maintaining the motor performance. In the prior art, there is a method of using a skewed stator slot to reduce the peak value of torque ripple, thereby reducing the vibration of the stator. However, this structure has complex technology, low production efficiency, and high cost. There is also a motor stator punching sheet disclosed in Chinese Patent CN205791830U. This solution is to make the arc of the tooth crown end face an eccentric arc, that is, the center of the arc is not at the center of the stator punching sheet. By changing the width of part of the air gap, high-order harmonics are reduced, thereby reducing the noise. However, the eccentric arc has high requirements for machining accuracy, and there are also problems of low production efficiency and high cost. Therefore, it is necessary to design a stator punching sheet that can reduce noise and is easy to implement. Summary of the Invention

[0004] Aiming at the above-mentioned deficiencies of the prior art, the purpose of the present invention is to provide a stator punching sheet, as well as a stator and a motor having the stator punching sheet, to solve the technical problem that it is difficult to reduce the noise of the motor through the existing stator punching sheet structure, and achieve the effect of easily reducing the noise of the motor on the premise of ensuring the motor performance.

[0005] To solve the above technical problems, the present invention adopts the following technical solutions: A stator punching sheet includes an annular yoke portion and a plurality of tooth portions connected to the yoke portion. The plurality of tooth portions are circumferentially distributed inside the yoke portion and extend radially. A tooth crown is formed at one end of the tooth portion away from the yoke portion. The end face of the tooth crown away from the yoke portion is a circular arc surface concentric with the yoke portion. Three grooves are circumferentially and equidistantly formed on the circular arc surface. The cross-section of the groove is circular arc-shaped and the axis is corresponding to the axis of the yoke portion.

[0006] Further, among the three grooves, the middle groove is located at the circumferential middle of the circular arc surface.

[0007] Further, the center distance between two adjacent grooves is L, and it satisfies L≤2R, where R is the circular arc radius of the groove.

[0008] Further, the circumferential two ends of the groove are smoothly connected to the circular arc surface through an arc transition surface.

[0009] Further, the depth of the groove on the circular arc surface is H, and it satisfies H=r, where r is the circular arc radius of the arc transition surface.

[0010] Further, the tooth portion includes a tooth body connected to the yoke portion and the tooth crown. Tooth grooves are formed between adjacent tooth bodies. The circumferential dimension of the tooth crown is larger than that of the tooth body. The notch of the tooth groove is formed between adjacent tooth crowns. The side surface of the tooth crown forming the notch is connected to the side surface of the tooth body where the tooth crown is located through an inclined surface.

[0011] Further, the radial dimension of the notch is hs0, the radial dimension of the inclined surface is hs1, and the circular arc radius of the groove is R, and it satisfies R=hs0+hs1.

[0012] Further, the radial dimension of the notch is hs0, the radial dimension of the inclined surface is hs1, and the circumferential dimension of the notch is bs0, and it satisfies bs0=hs0+hs1.

[0013] The present invention also includes a stator, which includes a stator core, and the stator core is obtained by axially facing and overlapping a plurality of the above-mentioned stator punching sheets.

[0014] The present invention also includes an electric motor, which includes a stator and a rotor. The stator includes a stator core, and the stator core is obtained by axially facing and overlapping a plurality of the above-mentioned stator punching sheets. The rotor is coaxially arranged inside the stator core and has a clearance fit.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. For the stator punch sheet of the present invention, three grooves are circumferentially and equidistantly formed on the tooth crown end face of the stator punch sheet. The presence of the grooves can not only increase the air gap width corresponding to a partial area of the tooth crown end face when the width of the air gap between the stator and the rotor remains small, but also make the width of the air gap between the stator and the rotor non-uniformly distributed in the circumferential direction when the stator and the rotor are coaxially aligned. This is beneficial to reducing the generation of high-order harmonics, which can not only reduce the no-load noise of the motor, but also take into account the optimization of the load noise. It can effectively solve the problem that it is difficult to reduce the motor noise through the existing stator punch sheet structure, improve the overall performance of the motor, reduce the noise level, and has good application prospects.

[0016] 2. For the stator punch sheet of the present invention, the structural design of the grooves is optimized. For example, the midpoint of the circumferential profile of the middle groove is located on the center line of the tooth part, and parameters such as the center distance between adjacent grooves are defined, which can make the magnetic circuit distribution more reasonable during the operation of the motor. This is not only beneficial to reducing the no-load noise, but also can optimize the load noise to a certain extent, thereby improving the overall performance of the motor. In addition, for the stator punch sheet of the present invention, it is also designed that the grooves and the tooth crown end face are smoothly connected through an arc transition surface, and the relevant dimensions of the tooth grooves are defined, ensuring the rationality and stability of the stator punch sheet structure. While reducing the noise, it will not affect the electromagnetic performance and mechanical performance of the motor. Description of the Drawings

[0017] Figure 1 is a schematic structural diagram of the stator punch sheet described in the background art; Figure 2 is a schematic structural diagram of the stator punch sheet described in the embodiment; Figure 3 is Figure 2 an enlarged schematic diagram of part A in Among them, yoke part 1, tooth part 2, tooth body 3, tooth crown 4, tooth groove 5, slot opening 6, groove 7, arc transition surface 8, inclined surface 9. Detailed Embodiment

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0019] Embodiment: Please refer to Figure 2 and Figure 3, A stator punching sheet, comprising an annular yoke portion 1 and a plurality of tooth portions 2 connected to the yoke portion 1. The plurality of tooth portions 2 are circumferentially distributed inside the yoke portion 1 and extend radially. A tooth crown 4 is formed at one end of the tooth portion 2 away from the yoke portion 1. The end face of the tooth crown 4 away from the yoke portion 1 is a circular arc surface concentric with the yoke portion 1. Three grooves 7 are circumferentially and equally spaced on the circular arc surface. The cross-section of the groove 7 is circular arc-shaped and the axis corresponds to the axis of the yoke portion 1.

[0020] For the stator punching sheet of the present invention, three grooves 7 are circumferentially and equally spaced on the end face of the tooth crown 4 of the stator punching sheet. The existence of the grooves 7 can not only increase the width of the air gap corresponding to a partial area of the end face of the tooth crown 4 when the width of the air gap between the stator and the rotor is kept small, but also make the width of the air gap between the stator and the rotor non-uniformly distributed in the circumferential direction when the stator and the rotor are coaxial. This is beneficial to reducing the generation of high-order harmonics, can not only reduce the no-load noise of the motor, but also take into account the optimization of the load noise, can effectively solve the problem that it is difficult to reduce the motor noise through the existing stator punching sheet structure, can improve the overall performance of the motor and reduce the noise level, and has good application prospects.

[0021] Please refer to Figure 2 and Figure 3 , among the three grooves 7, the middle groove 7 is located at the circumferential middle of the circular arc surface, that is, the center line of the tooth portion 2 passes through the midpoint of the circumferential contour of the middle groove 7.

[0022] Please refer to Figure 2 and Figure 3 , the circumferential two ends of the groove 7 are smoothly connected to the circular arc surface through an arc transition surface 8, that is, the arc contour lines of the arc transition surface 8 are respectively tangent to the arc contour line of the groove 7 and the arc contour line of the end of the tooth crown 4.

[0023] Please refer to Figure 2 and Figure 3 , the tooth portion 2 includes a tooth body 3 connected to the yoke portion 1 and the tooth crown 4. Tooth slots 5 are formed between adjacent tooth bodies 3. The circumferential dimension of the tooth crown 4 is larger than that of the tooth body 3. Slot openings 6 of the tooth slots 5 are formed between adjacent tooth crowns 4. The side surface of the tooth crown 4 forming the slot opening 6 is connected to the side surface of the tooth body 3 where the tooth crown 4 is located through an inclined surface 9; in this embodiment, there are fillets at the connection between the inclined surface 9 and the side surface of the tooth crown 4 and at the connection between the inclined surface 9 and the side surface of the tooth body 3.

[0024] Define the center distance between the centers of two adjacent grooves 7 as L, the depth of the groove 7 on the arc surface as H, the arc radius of the groove 7 as R, the arc radius of the arc transition surface 8 as r, the radial dimension of the notch 6 (i.e., the depth of the notch 6) as hs0, the radial dimension of the inclined surface 9 (i.e., the shoulder depth of the notch 6) as hs1, and the circumferential dimension of the notch 6 (i.e., the width of the notch 6) as bs0; when machining the grooves 7 on the tooth part 2 of the punching sheet for positioning and the end face of the tooth crown 4, its dimensional parameters should be strictly controlled to meet the following relational expressions: L ≤ 2R, H = r, R = hs0 + hs1, bs0 = hs0 + hs1. In this embodiment, preferably L = 2R.

[0025] The present invention optimizes the structural design of the groove 7. For example, making the midpoint of the circumferential contour of the middle groove 7 located on the center line of the tooth part 2 and defining parameters such as the center distance between adjacent grooves 7 can make the magnetic circuit distribution more reasonable during the operation of the motor. This is not only beneficial to reducing the no-load noise but also can optimize the load noise to a certain extent, thereby improving the overall performance of the motor; in addition, the present invention also designs the groove 7 and the end face of the tooth crown 4 to be smoothly connected through the arc transition surface 8 and defines the relevant dimensions of the tooth slot 5, ensuring the rationality and stability of the stator punching sheet structure. While reducing the noise, it will not affect the electromagnetic performance and mechanical performance of the motor.

[0026] This embodiment further includes a stator, and the stator includes a stator core, which is obtained by axially facing and overlapping a plurality of stator punching sheets as described above; this embodiment further includes a motor, and the motor includes a rotor and the stator as described above, and the rotor is coaxially arranged inside the stator core and is in clearance fit; during implementation, when the stator punching sheets overlap, they can be fixedly connected together by means such as welding, riveting, or bonding. When overlapping, it should be ensured that the tooth parts 2 and the grooves 7 on each stator punching sheet are axially aligned one by one to ensure the overall performance and stability of the stator.

[0027] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the technical solutions. Those of ordinary skill in the art should understand that any modifications or equivalent replacements made to the technical solutions of the present invention without departing from the purpose and scope of the present technical solution should be covered within the scope of the claims of the present invention.

Claims

1. A stator punching sheet, comprising an annular yoke portion and a plurality of tooth portions connected to the yoke portion, the plurality of tooth portions being circumferentially distributed inside the yoke portion and extending radially, and a tooth crown being formed at one end of the tooth portion away from the yoke portion, characterized in that: The end face of the tooth crown away from the yoke is an arc surface concentric with the yoke. Three grooves are equidistantly arranged along the circumference on the arc surface. The cross-section of the groove is arc-shaped and the axis corresponds to the axis of the yoke.

2. The stator punching sheet according to claim 1, wherein: Among the three grooves, the middle groove is located in the middle of the circumference of the arc surface.

3. The stator punching sheet according to claim 1, wherein: The center distance between two adjacent grooves is L, and L≤2R, where R is the arc radius of the groove.

4. The stator punching sheet according to claim 1, wherein: The two circumferential ends of the groove are smoothly connected to the arc surface through an arc transition surface.

5. The stator punching sheet according to claim 4, wherein: The depth of the groove on the arc surface is H, and H=r, where r is the arc radius of the arc transition surface.

6. The stator punching sheet according to claim 1, wherein: The tooth part includes a tooth body connected to the yoke and the tooth crown. Tooth spaces are formed between adjacent tooth bodies. The circumferential dimension of the tooth crown is larger than that of the tooth body. The side surfaces of the tooth crowns forming the tooth space opening are connected to the side surfaces of the tooth bodies where the tooth crowns are located through inclined surfaces.

7. The stator punching sheet according to claim 6, wherein: The radial dimension of the tooth space opening is hs0, the radial dimension of the inclined surface is hs1, and the arc radius of the groove is R, and R=hs0+hs1.

8. The stator punching sheet according to claim 6, characterized in that: The radial dimension of the tooth space opening is hs0, the radial dimension of the inclined surface is hs1, and the circumferential dimension of the tooth space opening is bs0, and bs0=hs0+hs1.

9. A stator, characterized in that: It includes a stator core, and the stator core is obtained by axially facing and overlapping a plurality of stator punching sheets as described in any one of claims 1-8.

10. A motor, characterized in that: It includes a stator and a rotor. The stator includes a stator core, and the stator core is obtained by axially facing and overlapping a plurality of stator punching sheets as described in any one of claims 1-8. The rotor is coaxially arranged inside the stator core and has a clearance fit.

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