Rotor punching, rotor core, motor, vehicle

Abstract

The present invention provides a rotor punching sheet, a rotor core, a motor, and a vehicle, wherein the rotor punching sheet includes a punching sheet body and a plurality of magnetic steel slots thereon, the magnetic steel slots have a first symmetry line in the radial direction of the punching sheet body, any two adjacent magnetic steel slots are symmetrical about the second symmetry line, and the contour line of the punching sheet body between any two adjacent second symmetry lines includes a first arc segment, a second arc segment, and a third arc segment corresponding to the magnetic steel slots, wherein the first arc segment intersects with the first symmetry line and is symmetrical about the first symmetry line, the second arc segment and the third arc segment are located on both sides of the first symmetry line and are symmetrical about the first symmetry line, and the first arc segment and the second arc segment have different curvature radii and curvature centers. A rotor punching sheet, a rotor core, a motor, and a vehicle according to the present invention can reduce cogging torque and torque fluctuation without increasing manufacturing difficulty or material cost.

Description

Technical Field

[0001] The invention belongs to the technical field of motor manufacturing, and in particular relates to a rotor punching sheet, a rotor core, a motor and a vehicle. Background Art

[0002] Permanent magnet synchronous motor has the characteristics of high torque density, low manufacturing cost, wide high efficiency zone, etc. It is the first choice for driving motors of new energy vehicles such as pure electric, hybrid and fuel cell. However, due to the existence of tooth slots in the structure of permanent magnet synchronous motor and harmonic distortion in the winding armature reaction, the permanent magnet synchronous motor has torque fluctuation during operation. The torque fluctuation of the motor is transmitted to the entire power system through the rotor shaft, generating some harmful vibrations, which will not only reduce the comfort of the surrounding environment, but also reduce the system efficiency and the service life of components. Therefore, in order to ensure the comfort of passengers, vehicle stability and economy, the torque fluctuation of permanent magnet synchronous motors for new energy vehicles needs to be limited to a reasonable range. It is best to design a new motor structure as simply and effectively as possible without increasing the difficulty of manufacturing and the cost of materials, so as to achieve the purpose of reducing harmonics, reducing torque fluctuations and improving system efficiency under the premise of low cost and easy manufacturing. Summary of the invention

[0003] Therefore, the technical problem to be solved by the present invention is to provide a rotor punching, a rotor core, a motor, and a vehicle, which can reduce the cogging torque and torque fluctuation without increasing the manufacturing difficulty and material cost by optimizing the cutting edge of the outer contour of the rotor punching.

[0004] In order to solve the above problems, the present invention provides a rotor punching sheet, including a punching sheet body, on which a plurality of magnetic steel slots are constructed, the magnetic steel slots having a first symmetry line in the radial direction of the punching sheet body, any two adjacent magnetic steel slots being symmetrical about a second symmetry line in the radial direction of the punching sheet body, and a contour line of the punching sheet body between any two adjacent second symmetry lines comprising a first arc segment, a second arc segment, and a third arc segment corresponding to the magnetic steel slots, wherein the first arc segment intersects with the first symmetry line and is symmetrical about the first symmetry line, the second arc segment and the third arc segment are located on both sides of the first symmetry line and are symmetrical about the first symmetry line, one end of the first arc segment is connected to the second arc segment through a first transition segment, the other end of the first arc segment is connected to the third arc segment through a second transition segment, the first transition segment and the second transition segment are symmetrical about the first symmetry line, and the first arc segment and the second arc segment have different curvature radii and curvature centers.

[0005] Optionally, the radius of curvature of the second arc segment is a second radius R, the second radius R is equal to the outer circle radius of the punch body, and the center of curvature of the second arc segment coincides with the outer circle center of the punch body; the center of curvature of the first arc segment is the intersection of a circle defined by the outer circle center and the first radius r and the first symmetry line, and r<R.

[0006] Optionally, r=0.44R.

[0007] Optionally, a central angle corresponding to the second arc segment is δ / 2, and 2.9°≤δ≤3.1°.

[0008] Optionally, the central angle corresponding to the first arc segment is w, 10δ≤w≤12δ.

[0009] Optionally, the first transition section and the second transition section are both straight line sections; and / or, a first magnetic isolation bridge is formed between any two adjacent magnetic steel slots, and the width of the first magnetic isolation bridge in the circumferential direction of the punching sheet body is c, 0.5mm≤c≤1mm.

[0010] Optionally, a second magnetic isolation bridge is formed between the slot end of any magnetic steel slot and the corresponding second arc segment, and the thickness of the second magnetic isolation bridge in the radial direction of the punching sheet body 1 is d, 0.5mm≤d≤1.2mm; and / or, the V-angle of any one of the multiple magnetic steel slots is θ, 90°≤θ≤120°.

[0011] The present invention also provides a rotor core, comprising a plurality of stacked rotor punchings, wherein the rotor punchings are the above-mentioned rotor punchings.

[0012] The present invention also provides a motor, comprising the above-mentioned rotor core.

[0013] The present invention also provides a vehicle, comprising a main drive motor, wherein the main drive motor is the motor described above.

[0014] The present invention provides a rotor punching sheet, a rotor core, a motor, and a vehicle, wherein the second arc segment, the third arc segment, the first transition segment, and the second transition segment are formed by cutting the punching sheet body on the basis of the original outer contour, and the specific setting positions of the first arc segment, the second arc segment, and the third arc segment are determined by the positions of the magnetic steel grooves, so as to achieve the purpose of improving the shape of the motor air gap. Without increasing the manufacturing difficulty and the manufacturing cost, the motor air gap formed by the punching sheet body 1 is made more sinusoidal, effectively weakening harmonics, reducing the cogging torque, and then reducing the motor torque fluctuation, thereby improving the system efficiency, reducing the motor vibration, and improving the comfort of the device using it, such as a vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the structure of the rotor punching according to an embodiment of the present invention (projected on any radial plane of the rotor punching);

[0016] Figure 2 for Figure 1 A local enlarged schematic diagram in FIG.

[0017] Figure 3 It is a schematic diagram of the three-dimensional structure of a rotor core according to another embodiment of the present invention;

[0018] Figure 4 The figure is a comparison data graph of torque fluctuations after simulation between a motor that adopts the technical solution of the present invention (with punching and trimming process) and a motor that does not adopt the technical solution of the present invention (without trimming process).

[0019] The reference numerals are:

[0020] 1. Punching sheet body; 11. Magnetic steel groove; 111. First arc segment; 112. Second arc segment; 113. Third arc segment; 114. First transition segment; 115. Second transition segment; 12. First magnetic isolation bridge; 13. Second magnetic isolation bridge; 14. Lightening hole; 15. Shaft hole; 2. Permanent magnet. DETAILED DESCRIPTION

[0021] See also Figures 1 to 4According to a specific embodiment of the present invention, a rotor punching sheet is provided, comprising a punching sheet body 1, a plurality of magnetic steel slots 11 configured on the punching sheet body 1 for embedding permanent magnets 2, the magnetic steel slots 11 having a first symmetry line in the radial direction of the punching sheet body 1, any two adjacent magnetic steel slots 11 being symmetrical about a second symmetry line in the radial direction of the punching sheet body 1, and a contour line of the punching sheet body 1 between any two adjacent second symmetry lines comprising a first arc segment 111, a second arc segment 112, and a third arc segment 113 corresponding to the magnetic steel slots 11, wherein the first arc segment 111 and the first pair of arc segments 113 are symmetrical about each other. The second arc segment 112 and the third arc segment 113 are located on both sides of the first symmetry line and are symmetrical about the first symmetry line. One end of the first arc segment 111 is connected to the second arc segment 112 through a first transition segment 114, and the other end of the first arc segment 111 is connected to the third arc segment 113 through a second transition segment 115. The first transition segment 114 and the second transition segment 115 are symmetrical about the first symmetry line. The first arc segment 111 and the second arc segment 112 have different curvature radii and curvature centers. In this technical solution, the second arc segment 112, the third arc segment 113, the first transition segment 114, and the second transition segment 115 are specifically formed by cutting the punching sheet body on the basis of the original outer contour (outer circle), and the specific setting positions of the first arc segment 111, the second arc segment 112, and the third arc segment 113 are determined by the position of the magnetic steel slot 11, so as to achieve the purpose of improving the shape of the motor air gap (stator and rotor air gap). Without increasing the manufacturing difficulty and material cost, the motor air gap formed by the punching sheet body 1 is made more sinusoidal, effectively weakening harmonics, reducing the cogging torque, and then reducing the motor torque fluctuation, thereby improving the system efficiency, reducing the motor vibration, and improving the comfort of the device using it, such as a vehicle.

[0022] In some embodiments, the radius of curvature of the second arc segment 112 is a second radius R, the second radius R is equal to the outer circle radius of the punch body 1, and the center of curvature of the second arc segment 112 coincides with the outer circle center of the punch body 1; the center of curvature of the first arc segment 111 is the intersection of the circle defined by the outer circle center and the first radius r and the first symmetry line, and r<R, preferably, r=0.44R, the center angle corresponding to the second arc segment is δ / 2, 2.9°≤δ≤3.1°, and the best, the center angle corresponding to the first arc segment is w, 10δ≤w≤12δ. Here, by limiting the center angles and radii corresponding to the first arc segment 111, the second arc segment 112 and the third arc segment 113, the cogging torque of the motor using them can be lower and the torque fluctuation can be smaller.

[0023] In some embodiments, the first transition section 114 and the second transition section 115 are both straight segments to further simplify the manufacturing process of the rotor punching sheet.

[0024] In order to reduce magnetic leakage and increase the utilization rate of permanent magnets, in some embodiments, a first magnetic isolation bridge 12 is formed between any two adjacent magnetic steel slots 11, and the width of the first magnetic isolation bridge 12 in the circumferential direction of the punching sheet body 1 is c, 0.5mm≤c≤1mm; a second magnetic isolation bridge 13 is formed between the slot end of any magnetic steel slot 11 and the corresponding second arc segment 112, and the thickness of the second magnetic isolation bridge 13 in the radial direction of the punching sheet body 1 is d, 0.5mm≤d≤1.2mm; the V-angle of any one of the multiple magnetic steel slots 11 is θ, 90°≤θ≤120°.

[0025] See Figure 1 As shown, the punching sheet body 1 is also constructed with an axial hole 15 for connecting with the rotating shaft, the magnetic steel slot 11 is V-shaped, and a plurality of the magnetic steel slots 11 are evenly spaced along the circumference of the punching sheet body 1, and a pair of permanent magnets 2 are placed in each magnetic steel slot 11 to form a magnetic pole, thereby forming an 8-pole magnetic steel embedded rotor, and its magnetic steel slot 11 can increase the q-axis inductance, thereby increasing the salient pole rate and improving the weak magnetic capability of the motor.

[0026] The punching sheet body 1 is also provided with a plurality of weight-reducing holes 14, which are arranged at the V-shaped bottom position of the V-shaped magnetic steel slot 11, and can effectively improve the q-axis magnetic circuit and the air gap magnetic density waveform, and reduce the cogging torque and torque fluctuation on the basis of increasing the salient pole rate.

[0027] In order to verify the actual effect of the technical solution of the present invention, the inventors conducted corresponding simulation tests and compared the simulation results with those of the motors that did not adopt the technical solution. Figure 4 It can be seen that the torque fluctuation of the motor is reduced from (untrimmed) 1.2268 (peak-to-peak value) / 10.0927 (effective value) = 12.155% to (trimmed) 0.5047 (peak-to-peak value) / 9.8363 (effective value) = 5.13%. It can be seen that when the permanent magnet slot angle of each pole, the magnetic isolation slot distance, and the trimming size are matched with appropriate parameters, the torque fluctuation of the motor is significantly reduced, which plays an important role in optimizing the performance of the product in actual production.

[0028] According to a specific embodiment of the present invention, there is further provided a rotor core, comprising a plurality of stacked rotor punchings, wherein the rotor punchings are the above-mentioned rotor punchings.

[0029] According to a specific embodiment of the present invention, there is also provided a motor, comprising the above-mentioned rotor core.

[0030] According to a specific embodiment of the present invention, there is further provided a vehicle, comprising a main drive motor, wherein the main drive motor is the motor described above.

[0031] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0032] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the present invention. The above are only preferred embodiments of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present invention, and these improvements and variations should also be regarded as the protection scope of the present invention.

Claims

1. A rotor punching, characterized in that: The invention comprises a punch body (1), wherein the punch body (1) is provided with a plurality of magnetic steel slots (11), wherein the magnetic steel slots (11) have a first symmetry line located in the radial direction of the punch body (1), and any two adjacent magnetic steel slots (11) are symmetrical about a second symmetry line located in the radial direction of the punch body (1), and the contour line of the punch body (1) located between any two adjacent second symmetry lines comprises a first arc segment (111), a second arc segment (112), and a third arc segment (113) corresponding to the magnetic steel slots (11), wherein the first arc segment (111) intersects with the first symmetry line and is symmetrical about the first symmetry line, the second arc segment (112) and the third arc segment (113) are located on both sides of the first symmetry line and are symmetrical about the first symmetry line, and one end of the first arc segment (111) is symmetrical to the magnetic steel slots (11). The second arc segment (112) is connected via a first transition segment (114); the other end of the first arc segment (111) is connected to the third arc segment (113) via a second transition segment (115); the first transition segment (114) and the second transition segment (115) are symmetrical about the first symmetry line; the first arc segment (111) and the second arc segment (112) have different radii of curvature and centers of curvature; the radius of curvature of the second arc segment (112) is a second radius R, the second radius R is equal to the outer circle radius of the punch body (1), and the center of curvature of the second arc segment (112) coincides with the outer circle center of the punch body (1); the center of curvature of the first arc segment (111) is the intersection of a circle defined by the outer circle center and the first radius r and the first symmetry line, and r<R.

2. The rotor punching according to claim 1, characterized in that: r=0.44R。 3. The rotor punching according to claim 1, characterized in that: The central angle corresponding to the second arc segment is δ / 2, 2.9°≤δ≤3.1°.

4. The rotor punching according to claim 3, characterized in that: The central angle corresponding to the first arc segment is w, 10δ≤w≤12δ.

5. The rotor punching according to any one of claims 1 to 4, characterized in that: The first transition section (114) and the second transition section (115) are both straight sections; and / or, a first magnetic isolation bridge (12) is formed between any two adjacent magnetic steel slots (11), and the width of the first magnetic isolation bridge (12) in the circumferential direction of the punching sheet body (1) is c, 0.5 mm ≤ c ≤ 1 mm.

6. The rotor punching according to any one of claims 1 to 4, characterized in that: A second magnetic isolation bridge (13) is formed between the slot end of any magnetic steel slot (11) and the corresponding second arc segment (112), and the thickness of the second magnetic isolation bridge (13) in the radial direction of the punching sheet body (1) is d, 0.5mm≤d≤1.2mm; and / or the magnetic steel slot (11) is a V-shaped magnetic steel slot, and the V-shaped magnetic steel slot has a V-angle of θ, 90°≤θ≤120°.

7. A rotor core, comprising a plurality of rotor punchings formed by stacking, characterized in that: The rotor punching is the rotor punching according to any one of claims 1 to 6.

8. A motor, comprising a rotor core, characterized in that: The rotor core is the rotor core according to claim 7.

9. A vehicle, comprising a main drive motor, characterized in that: The main drive motor is the motor described in claim 8.

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