JP2005192263A - Permanent magnet motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a permanent magnet motor in which reduction in torque is suppressed, cogging torque is reduced and the rotor rotates only in one direction. <P>SOLUTION: When an auxiliary groove 7 is provided at a part of a teeth portion 1 facing the surface of a rotor 10, only one auxiliary groove 7 is formed on the rotating and advancing side 9 of the center 5 of teeth portion. The auxiliary groove 7 is provided at a position, corresponding to a mechanical angle of (360/L)×(n+1/2) degree (n is an integer) from the center of slot opening, assuming the number of poles of the permanent magnet 3 of the rotor 10 is P, the number of poles of the teeth portion 1 is S; and the least common multiple of the number of pole P of the permanent magnet 3 of the rotor 10 and the number of poles S of the teeth portion 1 is L, thus providing a permanent magnet motor in which reduction in torque is suppressed, cogging torque is reduced and the rotor rotates only in one direction. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a permanent magnet motor as a power source used in a wide range of fields.

  Conventionally, when there is no auxiliary groove, the number of poles of the permanent magnet and the order of the least common multiple of the salient pole portions of the stator field core are the cogging torque per one rotation of the rotor. When there is an auxiliary groove, the number of apparent salient poles increases, the order of the cogging torque per rotor rotation increases, and the higher-order component is included in the fundamental component of the cogging torque. Reduced cogging torque.

As an idea to reduce the cogging torque, there are, for example, Japanese Patent Laid-Open Nos. 10-42531 and 2000-156958, in which auxiliary grooves are provided in a portion of the teeth portion facing the rotor surface. Japanese Patent Laid-Open No. 2001-309584 discloses an example in which the biased directions of adjacent auxiliary grooves are alternately different and formed in a position biased to one side. The auxiliary grooves include those provided on the left and right from the center of the teeth portion, those provided on the central portion, and the like.
Japanese Patent Laid-Open No. 10-42531 JP 2000-156958 A JP 2001-309584 A

  In the above publication, the auxiliary groove reduces the cogging torque by being provided on the left and right sides of the center of the tooth portion or in the central portion. However, there are cases where the torque is reduced more than without the auxiliary groove.

  The present invention solves the above-mentioned conventional problems in a permanent magnet having only one direction of rotation of the rotor, and provides a configuration that suppresses torque reduction as much as possible and reduces cogging torque. It is a problem.

  In order to solve the above-mentioned problems, the present invention provides that the rotation direction of the rotor is only one direction, and when the auxiliary groove is provided in the tooth portion facing the rotor, the auxiliary groove is located on the rotational advance side from the center of the tooth portion. Only one is formed, and the position of the auxiliary groove is the number of poles P of the rotor and the number of poles S of the teeth portion, and the least common multiple of the number of poles P of the rotor and the number of poles S of the teeth portion is L. The auxiliary groove is provided at a position corresponding to a mechanical angle (360 / L) × (n + 1/2) degrees (where n is an integer) from the center of the slot opening.

  According to the present invention, when current is applied, the cogging torque is applied by the first auxiliary groove provided on the rotation forward side from the center of the tooth portion without interfering with the generation of effective magnetic flux on the reverse rotation side from the center of the tooth where the magnetic flux density becomes high. Thus, a permanent magnet motor in which the rotation of the rotor with low cogging torque is unidirectional can be obtained.

According to a first aspect of the present invention, there is provided a permanent magnet motor comprising a plurality of teeth portions each provided with windings, a stator including a yoke portion connecting the teeth portions, and a rotor including a permanent magnet. When the auxiliary groove is provided in a portion facing the rotor surface of the tooth portion, one auxiliary groove is formed on the rotational advance side from the center of the tooth portion, and the auxiliary groove is provided. The position of the groove is the number of poles P of the rotor and the number of poles S of the teeth portion, and the least common multiple of the number of poles P of the rotor and the number of poles S of the teeth portion is L. 360 / L) × (n + 1/2) degrees (where n is an integer), the auxiliary groove is provided to suppress torque reduction and reduce cogging torque. It is obtained by only.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. The following example is an example embodying the present invention, and does not limit the technical scope of the present invention.

  In FIG. 1, the teeth portion 1, the yoke portion 2, the permanent magnet 3, the slot opening 4, the teeth portion center 5, the angle 6 from the slot opening center to the auxiliary groove center, and only one is formed on the rotation forward side from the teeth portion center. The auxiliary groove 7, the rotor 10, the stator 11, and the rotation direction 12 of the rotor, and FIG. 1 is an example of the present invention which is a permanent magnet motor having 8 magnet poles and 12 slots.

  According to such a configuration, in FIG. 2, the magnetic flux density on the reverse rotation side is higher than the center of the teeth portion opposed to the rotor from the center of the teeth portion opposed to the rotor, and the reverse rotation of the teeth is centered on the tooth portion center. Since the auxiliary groove is not located on the side, the reduction of the effective magnetic flux generated in the tooth portion on the reverse rotation side from the center of the tooth portion where the magnetic flux density is high is suppressed, and the magnetic flux density is smaller than that on the reverse rotation side from the center of the tooth portion. An auxiliary groove for reducing the cogging torque is provided on the rotational advance side from the center of the tooth portion, and the position of the auxiliary groove corresponds to a mechanical angle (360 / L) × (n + 1/2) degrees from the center of the slot opening. In the example shown in the figure, the auxiliary groove is provided at a position of 22.5 + 30 × m degrees (where m is an integer) to suppress torque reduction and reduce cogging torque. Can be reduced.

The electric motor according to the present invention can be used for electric motors in various fields because it can suppress a decrease in torque and reduce a cogging torque.

Sectional drawing which shows the permanent magnet motor in embodiment of this invention Magnetic flux diagram of the analysis result when current is applied to a permanent magnet motor with no auxiliary groove Magnetic flux density distribution diagram of analysis results when current is applied to a permanent magnet motor with no auxiliary groove

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Teeth part 2 Yoke part 3 Permanent magnet 4 Slot open 5 Center of teeth part 6 Angle from slot open center to auxiliary groove center 7 Auxiliary groove 8 Reverse rotation side 9 Rotary forward side 10 Rotor 11 Stator 12 Rotor rotation direction

Claims (2)

In a permanent magnet motor comprising a plurality of teeth portions provided with windings, a stator comprising a yoke portion connecting the teeth portions, and a rotor rotating only in one direction provided with a permanent magnet,
In providing an auxiliary groove in a portion of the teeth portion facing the surface of the rotor, only one auxiliary groove is formed on the rotational advance side from the center of the teeth portion, and the position of the auxiliary groove is determined by the rotor. The number of poles P and the number of poles S of the teeth section, and the least common multiple of the number of poles P of the rotor and the number of poles S of the teeth section are L, and the mechanical angle (360 / L) × (n + 1) / 2) Teeth in which the auxiliary grooves are provided at positions corresponding to degrees (where n is an integer). A permanent magnet motor that rotates only in one direction, wherein the teeth according to claim 1 are used.