CN-122026661-A - Brushless motor and servo control system

Abstract

A brushless motor includes a stator assembly, a rotor assembly disposed outside the stator assembly in a radial direction, the rotor assembly configured to rotate relative to the stator assembly, a torque holding assembly including a torque holding ring made of a permanent magnet material and fixed to the stator assembly, a torque holding plate made of a magnetically conductive material and fixed to the rotor assembly, wherein the torque holding ring has an annular first body and a plurality of magnetic pole units disposed in a circumferential direction, the magnetic pole units being composed of an N pole and an S pole, and wherein the torque holding plate has an annular second body and a plurality of salient poles spaced apart in the circumferential direction, the second body being disposed outside the first body in the radial direction, each salient pole facing a corresponding magnetic pole unit.

Inventors

• YAN SHIWEI
• YANG JIN
• CHI XIAOFENG
• YANG YANXIANG

Assignees

• 江苏雷利电机股份有限公司

Dates

Publication Date

20260512

Application Date

20241108

Claims (15)

1. 1. A brushless motor, comprising: A stator assembly; A rotor assembly disposed radially outward of the stator assembly, the rotor assembly configured to rotate relative to the stator assembly; A torque-holding assembly, comprising: a torque retaining ring secured to the stator assembly; a torque retention plate secured to the rotor assembly; wherein the torque holding ring has an annular first body and a plurality of magnetic pole units arranged in a circumferential direction, the magnetic pole units being made of a permanent magnet material, the magnetic pole units being composed of an N-pole and an S-pole; and wherein the torque holding plate has a ring-shaped second body and a plurality of salient poles spaced apart in the circumferential direction, the salient poles being made of a magnetically conductive material, the second body being arranged outside the first body in the radial direction, each of the salient poles facing a corresponding magnetic pole unit.
2. 2. The brushless electric machine of claim 1, wherein The stator assembly includes a stator frame, a support frame, and a stator core member fixed to the stator frame, the support frame being located radially inward of the torque retaining ring, the torque retaining ring being fixed to the stator frame by the support frame; The rotor assembly includes a rotor yoke and an exciting permanent magnet fixed to an inner surface of the rotor yoke and arranged outside the stator core member in the radial direction, and the torque holding plate is fixed to the rotor yoke.
3. 3. The brushless motor according to claim 1, wherein the salient poles protrude from the second body in an axial direction, the salient poles facing N poles or S poles of the magnetic pole units in the radial direction.
4. 4. A brushless motor according to claim 3, wherein the salient poles are provided with grooves extending in the radial direction on a side away from the second main body.
5. 5. The brushless motor according to claim 4, wherein the torque holding plate further includes a plurality of additional salient poles spaced apart in the circumferential direction, each of the additional salient poles being arranged in the vicinity of a corresponding salient pole, the additional salient poles protruding inward in the radial direction from the second body, the additional salient poles facing an N pole or an S pole of the magnetic pole unit in the axial direction.
6. 6. The brushless motor according to claim 5, wherein the torque holding plate further includes a plurality of additional pairs of projections spaced apart in the circumferential direction, each of the additional pairs of projections including two additional salient poles facing N poles or S poles of the magnetic pole unit on both sides in the axial direction, respectively.
7. 7. The brushless motor of claim 5, wherein the pole units are magnetized such that the salient poles face one of N and S poles of the pole units, and the additional salient poles face the other of N and S poles of the pole units.
8. 8. The brushless motor according to claim 1 or 2, wherein the magnetic pole units are arranged continuously in the circumferential direction.
9. 9. A brushless motor according to claim 1 or 2, wherein the pole units are spaced apart in the circumferential direction.
10. 10. The brushless motor according to claim 9, wherein the magnetic pole unit is constituted by a pair of N-pole and S-pole arranged in the circumferential direction.
11. 11. The brushless motor according to claim 9, wherein the magnetic pole unit is constituted by a pair of N-pole and S-pole arranged in the radial direction.
12. 12. A brushless motor according to any one of claims 9 to 11, wherein the pole units are arranged on an outer surface of the holder.
13. 13. A brushless motor according to any one of claims 9 to 11, wherein the pole units are embedded inside a holder.
14. 14. A brushless electric machine according to any one of claims 1 to 13, wherein the pole units are made by sintering, bonding or a plastic-magnetic process.
15. 15. A servo control system comprising a brushless motor according to any one of claims 1 to 14.

Description

Brushless motor and servo control system Technical Field The present invention relates to a brushless motor and a servo control system, and more particularly, to a brushless motor with higher positioning accuracy and a servo control system including the same. Background When energized, the rotor of the brushless motor rotates relative to the stator to output torque and rotational speed outwardly. In the case of a brushless motor being de-energized, it is desirable that the rotor be able to remain in a certain fixed position, so that a holding torque needs to be applied to the rotor to fix the rotor. In the prior art, the position of the rotor remains relatively low in accuracy during the de-energization of the brushless motor. For this reason, it is desirable to propose a brushless motor that improves on the drawbacks of the prior art described above. Disclosure of Invention According to a first aspect of the present invention, there is provided a brushless motor including a stator assembly, a rotor assembly arranged outside the stator assembly in a radial direction, the rotor assembly configured to rotate relative to the stator assembly, a torque holding assembly including a torque holding ring fixed to the stator assembly, a torque holding plate fixed to the rotor assembly, wherein the torque holding ring has a ring-shaped first body and a plurality of magnetic pole units arranged in a circumferential direction, the magnetic pole units being made of a permanent magnet material, the magnetic pole units being made of an N-pole and an S-pole, and wherein the torque holding plate has a ring-shaped second body and a plurality of salient poles spaced apart in the circumferential direction, the salient poles being made of a magnetically conductive material, the second body being arranged outside the first body in the radial direction, each salient pole facing a corresponding magnetic pole unit. According to this aspect, the torque holding ring can apply torque to the torque holding plate due to a magnetoresistive effect between the magnetic poles of the torque holding ring and the salient poles of the torque holding plate to hold the torque holding plate in a fixed position with respect to the torque holding ring, thereby holding the rotor in a fixed position with respect to the stator. By providing more poles and corresponding salient poles, the position maintaining accuracy of the rotor assembly can be improved. In some aspects, the stator assembly may include a stator frame, a support frame and a stator core member, the stator core member being fixed to the stator frame, the support frame being located radially inward of a torque retaining ring, the torque retaining ring being fixed to the stator frame by the support frame, the rotor assembly may include a rotor yoke and an excitation permanent magnet fixed to an inner surface of the rotor yoke and arranged radially outward of the stator core member, the torque retaining plate being fixed to the rotor yoke. In some aspects, the salient poles may protrude from the second body in an axial direction, the salient poles facing N or S poles of the magnetic pole units in a radial direction. According to this aspect, the magnetic poles can apply a holding torque in the circumferential direction to the salient poles, so that the rotor assembly is held stationary in the circumferential direction. In some aspects, the salient poles may be provided with grooves extending in a radial direction at a side remote from the second body. According to the scheme, the grooves can properly reduce the acting force of the magnetic poles on the salient poles, so that the salient poles cannot swing violently under the action of the magnetic poles, and the rotor assembly rotates more stably. In some aspects, the torque holding plate may further include a plurality of additional salient poles spaced apart in the circumferential direction, each of the additional salient poles being disposed near a corresponding salient pole, the additional salient poles protruding inward in the radial direction from the second body, the additional salient poles facing the N-pole or the S-pole of the magnetic pole unit in the axial direction. According to this solution, the poles are able to apply an additional circumferential holding torque to the additional salient poles, thereby better keeping the rotor assembly stationary. In some aspects, the torque holding plate may further include a plurality of additional salient pole pairs spaced apart in the circumferential direction, each additional salient pole pair including two additional salient poles facing the N-pole or the S-pole of the magnetic pole unit on both sides in the axial direction, respectively. According to this arrangement, the magnetic poles can apply additional holding torque to the two additional salient poles of the additional salient pole pair, respectively, and the position holding accuracy of the rotor assembly is improved. In some as