CN-122029725-A - Motor for electric compressor and electric compressor provided with motor for electric compressor

Abstract

The invention provides a motor for an electric compressor, which can effectively reduce cogging torque and torque pulsation while maintaining average torque. The rotor (24) has a plurality of magnet insertion holes (31) formed in the circumferential direction at the outer peripheral portion facing the tip end surfaces of the teeth (27), the permanent magnets (32) are respectively embedded in the magnet insertion holes (31), and the rotor (24) is disposed with a gap (28) between the outer peripheral surface and the tip end surfaces of the teeth (27). The rotor is provided with a gap (44) formed in the outer peripheral part of the rotor (24) in the rotation direction when viewed from the d-axis constituting the single magnetic pole, and a recess (34) formed in the outer peripheral surface of the rotor (24) in the direction opposite to the rotation direction when viewed from the d-axis.

Inventors

• SUGIURA AKIRA

Assignees

• 三电株式会社

Dates

Publication Date

20260512

Application Date

20240913

Priority Date

20231020

Claims (5)

1. 1. A motor for an electric compressor is characterized in that, The motor for the electric compressor is composed of a stator having a plurality of teeth protruding from an annular base to the radial inner side and a rotor having a plurality of magnetic poles composed of permanent magnets, The rotor has a plurality of magnet insertion holes formed in a circumferential direction at an outer peripheral portion facing the tip end surfaces of the teeth, the permanent magnets are respectively embedded in the magnet insertion holes, the rotor is arranged with a gap between the outer peripheral surface and the tip end surfaces of the teeth, and The rotor includes a void portion formed in an outer peripheral portion of the rotor in a rotation direction when viewed from a d-axis constituting a single magnetic pole, and a recess portion formed in an outer peripheral surface of the rotor in a direction opposite to the rotation direction when viewed from the d-axis.
2. 2. The motor for an electric compressor according to claim 1, wherein, The gap is formed continuously from the magnet insertion hole toward the outer peripheral surface of the rotor, the tip is arc-shaped, The concave portion is composed of a convex arc-shaped portion continuous from the outer peripheral surface of the rotor and a concave arc-shaped portion continuous with the convex arc-shaped portion, and a straight line portion parallel to the magnet insertion hole is continuously formed with the concave arc-shaped portion.
3. 3. A motor for an electric compressor according to claim 2, wherein, A distance between the center of the arc of the tip of the gap and the magnet insertion hole is L, The distance from the outer peripheral surface of the rotor to the magnet insertion hole on the d-axis is Lm, When a point at which a perpendicular drawn from the center of the arc of the tip of the void portion toward the magnet insertion hole intersects with the magnet insertion hole is a, L/Lm is set to be 0.25-0.4, An angle [ theta ] 1 formed by a line passing through the point A from the center of the outer diameter of the rotor and the d-axis is set to 20 DEG [ theta ] 1 [ theta ] 25 DEG in terms of an electric angle.
4. 4. A motor for an electric compressor according to claim 3, wherein, When the point at which the convex arc-shaped portion and the concave arc-shaped portion constituting the concave portion are connected is set as B, An angle θ2 formed by a line passing through the point B from the center of the outer diameter of the rotor and the d-axis is set to 33 ° or more and θ1 or less and 48 ° in terms of an electric angle.
5. 5. An electric compressor, which is characterized in that, The motor for an electric compressor according to any one of claims 1 to 4 and a compression element driven by the motor for an electric compressor are accommodated in a container.

Description

Motor for electric compressor and electric compressor provided with motor for electric compressor Technical Field The present invention relates to, for example, a motor for an electric compressor which is housed in a container and drives a compression element, and an electric compressor provided with the motor for an electric compressor. Background Conventionally, in an electric compressor used in a refrigeration cycle, a permanent magnet synchronous motor in which permanent magnets are embedded in a rotor is used. However, this permanent magnet synchronous motor has a problem that if cogging torque or torque ripple increases, vibration noise generated increases. In general, the average torque output from the motor has a correlation with the cogging torque, and the average torque has a correlation with the torque ripple, and when one of the torques increases, the other torque also increases. Accordingly, a large number of methods have been proposed to reduce cogging torque and torque ripple while maintaining average torque (for example, see patent literature 1). Patent document 1 Japanese patent application No. 6507956 Fig. 15 shows a conventional permanent magnet synchronous motor 100 having a configuration for reducing cogging torque and torque ripple as described above. Fig. 15 shows a cross section perpendicular to the axial direction of the motor 100. In the figure, 101 is a stator, and 102 is a rotor. The stator 101 includes an annular base 103, a plurality of teeth 104 protruding radially inward from the base 103, and a winding, not shown, wound around the teeth 104. The rotor 102 is disposed with a gap 106 between the tip end surfaces of the teeth 104 of the stator 101. The rotor 102 is configured by a rotor core 107, a plurality of magnet insertion holes 108 formed in the circumferential direction in the outer peripheral portion of the rotor core 107, and permanent magnets 109 embedded in the magnet insertion holes 108. In the case of the conventional motor 100 shown in fig. 15, for example, a gap expansion portion 111 is formed on the outer peripheral surface at a position corresponding to between adjacent magnet insertion holes 108. The circle shown by X in fig. 15 indicates a case where the outer peripheral surface of the rotor 102 has a true circular shape, and the clearance expanding portion 111 is formed by recessing the outer peripheral surface of the portion more than the circle X. By providing such a gap enlarging portion 111, the magnetic force in this portion is reduced, and the force that attempts to advance the rotor 102 in the rotational direction and the force that returns are reduced, so that the cogging torque and torque ripple can be reduced, but the effect is limited. Disclosure of Invention The present invention has been made to solve the problems of the prior art, and an object of the present invention is to provide a motor for an electric compressor capable of effectively reducing cogging torque and torque ripple while maintaining an average torque, and an electric compressor provided with the motor for an electric compressor. The motor for an electric compressor of the present invention is characterized in that the motor for an electric compressor is composed of a stator having a plurality of teeth protruding radially inward from an annular base portion, and a rotor having a plurality of magnetic poles composed of permanent magnets, the rotor has a plurality of magnet insertion holes formed in the circumferential direction at an outer peripheral portion facing a tip end surface of the teeth, the permanent magnets are embedded in the magnet insertion holes, respectively, the rotor is disposed with a gap between the outer peripheral surface and the tip end surface of the teeth, and the rotor has a void portion formed at the outer peripheral portion in the rotation direction of the rotor when viewed from a d-axis constituting a single magnetic pole, and a recess portion formed at the outer peripheral surface in the direction opposite to the rotation direction of the rotor when viewed from the d-axis. In the motor for an electric compressor according to the aspect 2 of the present invention, the gap is formed continuously in a direction from the magnet insertion hole toward the outer peripheral surface of the rotor, the tip is formed in an arc shape, the concave portion is formed by a convex arc-shaped portion continuous from the outer peripheral surface of the rotor and a concave arc-shaped portion continuous with the convex arc-shaped portion, and a straight line portion parallel to the magnet insertion hole is formed continuously with the concave arc-shaped portion. In the motor for an electric compressor according to the aspect 3 of the present invention, when the distance between the center of the arc of the tip of the gap and the magnet insertion hole is L, the distance from the outer peripheral surface of the rotor to the magnet insertion hole on the d-axis is Lm, the poin