JP2000175388A - Permanent magnet burial type motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of manufacturing man-hours and to improve motor characteristics. SOLUTION: A permanent magnet 24 that becomes a field source is inserted into a magnet insertion groove 23 that is provided at a rotor core 22. A groove 23a for inserting a spring is provided on the lower surface of the magnet insertion groove 23, and a spring for fixing 25 is inserted into the groove 23a for inserting the spring. The spring 25 for fixing fixes the position of a permanent magnet 24 for energizing the permanent magnet 24 toward the upper surface of the magnet insertion groove 23, thus eliminating the need for the adhesion process of the permanent magnet 24. Also, the position of the permanent magnet 24 in a system direction becomes constant, thus preventing a torque ripple from being generated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent-magnet embedded motor, in which a structure for fixing a permanent magnet to a rotor core is devised to reduce the number of manufacturing steps and improve motor characteristics.

[0002]

2. Description of the Related Art A permanent magnet motor is a rotating machine using a permanent magnet as a field source provided in a rotor core. This permanent magnet motor is advantageous over an induction motor in terms of high efficiency, miniaturization, and the like, and has attracted attention. Permanent magnet motors can be broadly classified into permanent magnet embedded motors (hereinafter abbreviated as “IPM motors”) and permanent magnet surface-attached motors (hereinafter abbreviated as “SPM motors”).

As shown in FIG. 5, the rotor of the SPM motor 1 is configured by attaching a permanent magnet 3 as a field source to a peripheral surface of a columnar rotor core 2.

On the other hand, in the rotor of the IPM motor 11, as shown in FIG. 6, a plurality of magnet insertion grooves 13 are provided in a cylindrical rotor core 12 formed by laminating thin steel plates. The magnet insertion grooves 13 are provided at equal pitches in the circumferential direction of the rotor core 12 and extend in the axial direction of the rotor core 12, and the number of the magnet insertion grooves 13 is an integral multiple of the number of poles (four in this example). ing.

A permanent magnet 14 serving as a magnetic field source is inserted into each magnet insertion groove 13, and the inserted permanent magnet 14 is bonded in the magnet insertion groove 13 with an adhesive. The shape of the magnet insertion groove 13 is slightly larger than that of the permanent magnet 14 so that the permanent magnet 14 can be inserted into the magnet insertion groove 13.

[0006]

The above-mentioned IPM
In the motor 11, the bonding operation requires steps such as application and curing of an adhesive, and the manufacturing process time is long.

Further, as shown in FIG. 7, the permanent magnet 14 may be fixed in the magnet insertion groove 13 to one side (in the direction of arrow A in FIG. 7) by the gap 15. In addition, the fixing position of the permanent magnet 14 may be slightly different in each pole. In addition, the fixed position of the permanent magnet 14 in the system direction varies with the displacement of the permanent magnet 14. This causes the rotor to be unbalanced or torque ripple.

The present invention has been made in view of the above prior art, and has as its object to provide a permanent magnet embedded motor that can reduce the manufacturing process time and has no rotor imbalance or torque ripple.

[0009]

The present invention for solving the above-mentioned problems comprises a columnar rotor core formed by laminating thin steel plates, and a number of poles provided in the rotor core at equal circumferential intervals. In a permanent magnet embedded motor including a magnet insertion groove extending in an axial direction that is an integral multiple of an integer and a permanent magnet inserted into the magnet insertion groove, a spring insertion groove is provided on a lower surface of the magnet insertion groove. A fixing spring for urging and fixing the permanent magnet inserted into the magnet insertion groove toward the upper surface of the magnet insertion groove is inserted into the spring insertion groove.

In the structure of the present invention, a relief surface is provided on the upper surface of the magnet insertion groove, the relief surface being a concave surface from which the permanent magnet bent by being urged by the fixing spring can project. It is characterized by the following.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings.

A permanent magnet embedded type motor (IPM motor) 21 according to a first embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1 and FIG.
In the rotor of the PM motor 21, a plurality of magnet insertion grooves 23 are provided in a cylindrical rotor core 22 formed by laminating thin steel plates. The magnet insertion grooves 23 are provided at equal pitches in the circumferential direction of the rotor core 22 and extend in the axial direction of the rotor core 22, and the number of the magnet insertion grooves 23 is an integral multiple of the number of poles.

On the lower surface (the surface on the inner peripheral side in the radial direction) of each magnet insertion groove 23, two spring insertion grooves 23 are respectively provided.
a is provided. Each spring insertion groove 23a extends in the axial direction of the rotor core 22.

As shown in FIG. 1, a fixing spring 25 is inserted into each spring insertion groove 23a. This fixing spring 2
5 is a front view in FIG. 3 (a), and FIG.
As shown in an end view which is a view taken in the direction of arrow B in (a), the shape is such that a sheet metal is bent.

As shown in FIG. 1, a permanent magnet 24 serving as a field source is inserted into each magnet insertion groove 23. The fixing spring 25 inserted into the spring insertion groove 23a urges the permanent magnet 24 inserted into the magnet insertion groove 23 toward the upper surface (the outer surface in the radial direction) of the magnet insertion groove 23.
For this reason, the inserted permanent magnet 24 is
Urged and fixed. That is, the permanent magnet 24 is fixed in the magnet insertion groove 23 without using an adhesive.

As described above, the permanent magnet 24 is
5, the fixing position does not shift even if there is a gap. Further, since the permanent magnet 24 is urged to the upper surface of the magnet insertion groove 23 by the fixing spring 25, the permanent magnet 24 is always in contact with the upper surface of the magnet insertion groove 23, and the radially fixed position of the permanent magnet 24 is fixed. Is eliminated. Therefore, the rotor is balanced and a stable torque output without torque ripple can be obtained.

In the above-described embodiment, a spring having a shape obtained by bending a sheet metal is used as the fixing spring. However, the shape of the spring may be any shape that can generate a spring force for fixing the magnet. Any shape may be used, such as a cylindrical spring pin or key.

Next, a permanent magnet embedded type motor (IPM motor) 21A according to a second embodiment of the present invention will be described with reference to FIG. As shown in FIG. 4, in the second embodiment, the magnet insertion grooves 23 provided in the rotor core 22 are provided.
Is provided with a concave relief surface 23b.

The structure of the other parts is the same as that of the first embodiment shown in FIG. 1, and the parts having the same functions are denoted by the same reference numerals, and redundant description will be omitted.

In this IPM motor 21A, since the relief surface 23b is provided on the upper surface of the magnet insertion groove 23, even if the permanent magnet 24 is bent by being urged by the fixing spring 25, the permanent magnet 24 can be released. You can escape to the side. For this reason, even if the permanent magnet 24 is bent by the spring urging force, it can be prevented from being damaged.

[0021]

According to the present invention, the permanent magnet inserted into the magnet insertion groove can be
Since the fixing spring is urged and fixed by the fixing spring inserted in the spring insertion groove, the bonding step is not required in the manufacturing process, and the number of steps and the manufacturing time can be reduced.

Further, since the permanent magnet is urged to the upper surface of the magnet insertion groove by the fixing spring, the permanent magnet always comes into contact with the upper surface of the magnet insertion groove, so that there is no variation in the fixed position of the magnet in the radial direction. As a result, the unbalance and torque ripple of the rotor are eliminated, and the motor characteristics are improved.

Furthermore, since the relief surface is provided on the upper surface of the magnet insertion surface, even if the permanent magnet is urged by the fixing spring and bends, the permanent magnet can protrude toward the relief surface, thereby preventing damage to the permanent magnet. be able to.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a rotor of a permanent magnet embedded motor (IPM motor) according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram showing a rotor core and a magnet insertion groove of the IPM motor according to the first embodiment;

FIG. 3 is a configuration diagram showing a fixing spring used in the first embodiment.

FIG. 4 is a configuration diagram showing a rotor of a permanent magnet embedded type motor (IPM motor) according to a second embodiment of the present invention.

FIG. 5 is a configuration diagram showing a rotor of a permanent magnet surface pasting type motor.

FIG. 6 is a configuration diagram showing a rotor of a conventional permanent magnet embedded type motor (IPM motor).

FIG. 7 is a configuration diagram showing a rotor of a conventional permanent magnet embedded type motor (IPM motor).

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 SPM motor 2 rotor core 3 permanent magnet 11 IPM motor 12 rotor core 13 magnet insertion groove 14 permanent magnet 15 gap 21, 21A IPM motor 22 rotor core 23 magnet insertion groove 23 a spring insertion groove 23 b relief surface 24 permanent magnet 25 fixing spring

Claims (2)

[Claims] 1. A cylindrical rotor core formed by laminating thin steel plates, a magnet insertion groove provided in the rotor core at equal pitches in a circumferential direction and extending in an axial direction of an integral multiple of the number of poles, and the magnet In a permanent magnet embedded motor having a permanent magnet inserted into an insertion groove, a spring insertion groove is provided on a lower surface of the magnet insertion groove, and the spring insertion groove is inserted into the magnet insertion groove. A permanent magnet embedded motor in which a fixing spring for urging and fixing a permanent magnet toward an upper surface of the magnet insertion groove is inserted. 2. A concave relief surface on which the permanent magnet bent by being urged by the fixing spring is protruded is provided on an upper surface of the magnet insertion groove. The permanent magnet embedded type motor according to claim 1.