JP2009247131A - Rotor of permanent magnet motor - Google Patents

Abstract

An object of the present invention is to provide a rotor of a permanent magnet electric motor capable of fixing a permanent magnet in a magnet insertion hole of a stator core without increasing a manufacturing process such as a process of applying an adhesive.
SOLUTION: First magnet stoppers 23a and 23b projecting in the inner diameter direction are formed at outer end portions on the outer core side portions 6a and 6b of the magnet insertion holes 20a and 20b, and the magnet insertion holes 20a and 20b are formed. Second magnet stoppers 24a and 24b projecting in the inner diameter direction are formed at the outer diameter side end of the 20b inter-magnet-insertion iron core portion 8 side.
[Selection] Figure 1

Description

  The present invention relates to a rotor of a permanent magnet motor, and more particularly to a rotor of a permanent magnet motor in which a rotor core is provided with a plurality of magnet insertion holes per pole and a permanent magnet is inserted into the magnet insertion hole.

As a rotor of a permanent magnet motor in which a plurality of magnet insertion holes are provided per pole in a rotor iron core and a permanent magnet is inserted into each of the magnet insertion holes, for example, the rotor disclosed in Patent Document 1 is proposed. ing.
FIG. 4 is a structural diagram mainly composed of one pole of the rotor of the permanent magnet motor described in Patent Document 1. Hereinafter, description will be given with reference to the drawings.
A rotor 1 of a permanent magnet motor includes a rotating shaft 2, a rotor core 3 formed by laminating magnetic metal plates such as steel plates in the rotating shaft direction, and a plurality of magnets provided in the rotor core 3. It has holes 4a, 4b and permanent magnets 5a, 5b embedded in the respective magnet insertion holes 4a, 4b. The permanent magnets 5a and 5b are formed in a rectangular parallelepiped shape, n is the N pole of the permanent magnets 5a and 5b, s is the S pole of the permanent magnets 5a and 5b, and the permanent magnets 5a and 5b are each pole surfaces n and s. Are inserted into the magnet insertion holes 4a and 4b so as to be parallel to the rotating shaft 2. FIG. 4 shows a case where two permanent magnets 5a and 5b are arranged per pole.
First flux barriers 7a and 7b are formed in the inter-electrode cores 6a and 6b on the inter-electrode side of the magnet insertion holes 4a and 4b, and between the magnet insertion holes between the magnet insertion hole 4a and the magnet insertion hole 4b. Second flux barriers 9a and 9b are formed in the iron core portion 8 to prevent magnetic flux leakage and short circuit.

Further, first magnet positioning portions 11a and 11b are formed on the inner diameter side of the inter-core core portions 6a and 6b, and second magnet positioning portions 12a and 12b are formed in the inter-magnet insertion hole core portion 8, The permanent magnets 5a and 5b are circumferentially positioned by the first magnet positioning portions 11a and 11b and the second magnet positioning portions 12a and 12b.
JP 2002-281700 A

In the manufacturing process of the rotor of the permanent magnet motor, the permanent magnets 5a and 5b are inserted into the magnet insertion holes 4a and 4b. In order to smoothly insert the permanent magnets 5a and 5b into the magnet insertion holes 4a and 4b. In addition, the magnet insertion holes 4a and 4b are usually formed so that the cross-sectional shape thereof is slightly larger than the cross-sectional shape of the permanent magnets 5a and 5b. For this reason, there is a slight gap between the magnet insertion holes 4a and 4b and the permanent magnets 5a and 5b.
By having this gap, the permanent magnets 5a and 5b are biased to be biased to either the outer diameter side or the inner diameter side in the magnet insertion holes 4a and 4b. In the case of FIG. 5a and 5b stick to the inner diameter side in the magnet insertion holes 4a and 4b.
FIG. 5A is a structural diagram in the case where the permanent magnet 5a is biased toward the outer diameter side within the magnet insertion hole 4a, and FIG. 5B is a structural diagram where the permanent magnet 5a is biased toward the inner diameter side within the magnet insertion hole 4a. FIG.
The magnetic flux density in the gap 14 between the rotor core 3 and the permanent magnet 5a when the permanent magnet 5a shown in FIG. 5A is biased to the outer diameter side is such that the permanent magnet 5a shown in FIG. The magnetic flux density is higher and the magnetic energy is larger than the gap 15 when biased to the side. This is because the presence of the first magnet positioning portion 11a makes the distance between the rotor core 3 and the permanent magnet 5a closer to the outer diameter side end of the magnet insertion hole 4a at the inner diameter side end of the magnet insertion hole 4a. Therefore, in the state of FIG. 5B, the magnetic resistance is smaller than in the state of FIG. 5A in which the permanent magnet 5a and the rotor core 3 face each other in a plane. Since the permanent magnet 5a finally moves to a position where the magnetic energy is minimized, the permanent magnet 5a is stabilized in the state shown in FIG. That is, in the case of FIG. 4, the permanent magnets 5a and 5b are in a state of being biased and biased toward the inner diameter side in the magnet insertion holes 4a and 4b.

When the permanent magnet 5a is attracted to the inner diameter side in the magnet insertion hole 4a in this way, when the centrifugal force accompanying the rotation of the rotor 1 exceeds the attracting force, the permanent magnet 5a is inserted into the magnet insertion hole 4a. However, when the rotation of the rotor 1 is weakened and the centrifugal force is less than the attractive force, the permanent magnet 5 moves to the inner diameter side of the magnet insertion hole 4a.
As described above, the permanent magnet 5a repeatedly moves in the radial direction within the magnet insertion hole 4a. Therefore, noise is generated during the rotation of the rotor 1, and in some cases, the permanent magnet 5a is cracked or chipped. Sometimes.
In order to prevent the permanent magnet 5a from moving in the radial direction accompanying the rotation of the rotor 1 as described above, it is necessary to fix the permanent magnet 5a in the magnet insertion hole 4a of the rotor core 3 with an adhesive or the like. In this case, however, not only an extra step of applying an adhesive in the manufacturing process is required, but also a large force is required when the permanent magnet 5a is inserted into the magnet insertion hole a. In particular, when the output of the electric motor increases, the amount of permanent magnet 5a embedded increases accordingly, which makes it difficult to manufacture the permanent magnet electric motor.
SUMMARY OF THE INVENTION An object of the present invention is to provide a rotor for a permanent magnet electric motor that can solve the above problems and can fix a permanent magnet in a magnet insertion hole of a stator core without increasing the number of manufacturing steps.

  In order to solve the above problems, the present invention provides a rotor of a permanent magnet motor in which a plurality of magnet insertion holes are provided per pole in a rotor core, and permanent magnets are inserted into the magnet insertion holes. Is divided into an inner diameter side and an outer diameter side so that the surface area of the permanent magnet that can be contacted with the magnet insertion hole is wider on the outer diameter side than on the inner diameter side.

  According to the present invention, when the permanent magnet is divided into the inner diameter side and the outer diameter side, the surface area that allows contact between the permanent magnet and the magnet insertion hole is made wider on the outer diameter side than on the inner diameter side. Is always biased toward the outer diameter side, so that there is no movement of the permanent magnet in the radial direction as the rotor rotates. As a result, there is no need to fix the permanent magnet with an adhesive or the like in the manufacturing process of the rotor of the permanent magnet motor, and the operation of inserting the permanent magnet into the magnet insertion hole becomes very easy.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. In all the drawings in the present specification, the same reference numerals are given to the portions corresponding to each other, and the description below will be appropriately applied to the overlapping portions. Omitted.
FIG. 1 is a structural diagram mainly showing one pole of a rotor of a permanent magnet motor showing an embodiment of the present invention, and shows a case where two permanent magnets are arranged in the circumferential direction per pole.
Reference numeral 1 denotes a rotor of a permanent magnet motor. The rotor 1 includes a rotor core 3 formed by laminating magnetic metal plate materials such as steel plates in the rotation axis direction, and a plurality of magnets formed on the rotor core 3. It has insertion holes 20a, 20b and rectangular parallelepiped permanent magnets 5a, 5b embedded in the respective magnet insertion holes 20a, 20b.
The magnet insertion hole 20a has a surface area that allows contact between the permanent magnet 5a and the magnet insertion hole 20a when the permanent magnet 5a is divided into an inner diameter side and an outer diameter side along a center line indicated by a one-dot chain line X in FIG. However, the outer diameter side is formed wider than the inner diameter side. Similarly, the magnet insertion hole 20b is also in contact with the permanent magnet 5b and the magnet insertion hole 20b when the permanent magnet 5b is divided into the inner diameter side and the outer diameter side along the center line indicated by the one-dot chain line X in FIG. The possible surface area is formed so that the outer diameter side is wider than the inner diameter side.

That is, the magnet insertion holes 20a and 20b are formed with first magnet stoppers 23a and 23b protruding in the inner diameter direction at the outer diameter side end portions on the inter-electrode core portions 6a and 6b side, Second magnet stoppers 24a and 24b projecting in the inner diameter direction are formed at the outer diameter side end portion on the iron core portion 8 side of the magnet insertion hole 20b. Here, the circumferential interval between the first magnet stopper 23a and the second magnet stopper 24a is substantially the same as the circumferential length of the permanent magnet 5a, and similarly, the first magnet stopper 23b. The distance between the second magnet stopper 24b in the circumferential direction is substantially the same as the circumferential length of the permanent magnet 5b, thereby preventing the permanent magnets 5a and 5b from moving in the circumferential direction. .
Further, first flux barriers 21a and 21b are formed in the inter-electrode cores 6a and 6b on the inter-electrode side of the magnet insertion holes 20a and 20b, and a magnet insertion hole between the magnet insertion hole 20a and the magnet insertion hole 20b. Second flux barriers 22a and 22b are formed in the intermediate core portion 8. The shape of the second flux barriers 22a and 22b has an arcuate corner in order to alleviate stress concentration.
As described above, by providing the first magnet stoppers 23a, 23b and the second magnet stoppers 24a, 24b protruding in the inner diameter direction at both outer diameter side ends of the magnet insertion holes 20a, 20b, the permanent magnet 5a, Since the permanent magnets 5a and 5b stick to the outer diameter side in the magnet insertion holes 20a and 20b for the following reasons, the permanent magnets 5a and 5b accompanying the rotation of the rotor 1 are prevented. The radial movement of 5b can also be prevented.

FIG. 2A is a structural diagram in the case where the permanent magnet 5a is biased to the outer diameter side in the magnet insertion hole 20a, and FIG. 2B is a structural diagram in which the permanent magnet 5a is biased to the inner diameter side in the magnet insertion hole 20a. FIG.
The magnetic flux density in the gap 15 between the rotor core 3 and the permanent magnet 5a when the permanent magnet 5a shown in FIG. 2B is biased toward the inner diameter side is such that the permanent magnet 5a shown in FIG. The magnetic flux density is higher and the magnetic energy is larger than the gap 14 when biased to the side. This is because the presence of the first magnet stopper 23a and the second magnet stopper 24a makes the distance between the rotor core 3 and the permanent magnet 5a at the outer diameter side end of the magnet insertion hole 20a smaller than that of the magnet insertion hole 20a. Since it is closer to the inner diameter side end, the state of FIG. 2A has a smaller magnetic resistance than the state of FIG. 2B in which the permanent magnet 5a and the rotor core 3 are opposed to each other in a plane. Because it becomes. Since the permanent magnet 5a finally moves to a position where the magnetic energy is minimized, the permanent magnet 5a is stabilized in the state shown in FIG. That is, the permanent magnet 5a is in a state of being biased and stuck to the outer diameter side in the magnet insertion hole 20a.
For this reason, the permanent magnet 5a is always attracted to the outer side iron core in the magnet insertion hole 20a regardless of whether the rotor 1 rotates or does not rotate, and the permanent magnet 5a does not move in the radial direction.

FIG. 3 is a structural diagram mainly showing one pole of a rotor of a permanent magnet motor showing a different embodiment of the present invention.
This embodiment shows the case where three permanent magnets 5a, 5b, 5c are arranged in the circumferential direction per pole, and the other configuration is the same as that of the embodiment of FIG. The same members are denoted by the same reference numerals and description thereof is omitted.
That is, in FIG. 3, 20c is a magnet insertion hole into which the permanent magnet 5c is inserted, and the third end of the magnet insertion hole 20c that protrudes in the inner diameter direction on the outer diameter side end portion on the iron core portion 8a side between the magnet insertion holes. The magnet stopper 24c is formed, and a fourth magnet stopper 24d that protrudes in the inner diameter direction is formed at the outer diameter side end of the magnet insertion hole 20c on the iron core portion 8b side between the magnet insertion holes. The circumferential interval between the third magnet stopper 24c and the fourth magnet stopper 24d is substantially the same as the circumferential length of the permanent magnet 5c.
As described above, the magnet insertion hole 20c is provided with the third magnet stopper 24c and the fourth magnet stopper 24d projecting in the inner diameter direction at both ends on the outer diameter side thereof, thereby allowing the permanent magnet 5c to move in the circumferential direction. As well as preventing radial movement.
A third flux barrier 22c is formed on the side of the core portion 8a between the magnet insertion holes between the magnet insertion hole 20c and the magnet insertion hole 20a, and magnet insertion between the magnet insertion hole 20c and the magnet insertion hole 20b is performed. A fourth flux barrier 22d is formed on the inter-hole core portion 8b side. The shapes of the third flux barrier 22c and the fourth flux barrier 22d are circular at the corners in order to relieve stress concentration as in the second flux barriers 22a and 22b.

  In the embodiment of FIG. 3, the case where three permanent magnets per pole are arranged in the circumferential direction is shown, but four or more permanent magnets may be arranged per pole.

Structural drawing mainly composed of one pole of a rotor of a permanent magnet motor showing an embodiment of the present invention FIG. 3 is a partially enlarged view of FIG. 2, in which (a) is a structural diagram when the permanent magnet is biased toward the outer diameter side within the magnet insertion hole, and (b) is a biased magnet toward the inner diameter side within the magnet insertion hole. Structure diagram Structural drawing mainly composed of one pole of a rotor of a permanent magnet motor showing a different embodiment of the present invention Structural diagram mainly composed of one pole of a rotor of a conventional permanent magnet motor FIG. 5 is a partially enlarged view of FIG. 4, where (a) is a structural diagram when the permanent magnet is biased toward the outer diameter side within the magnet insertion hole, and (b) is a biased magnet toward the inner diameter side within the magnet insertion hole. Structure diagram

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Rotor 3 ... Rotor core 5a, 5b, 5c ... Permanent magnet 20a, 20b, 20c ... Magnet insertion hole 23a, 23b ... 1st magnet stop part 24a, 24b. ..Second magnet stopper

Claims (3)

In a rotor of a permanent magnet motor in which a plurality of magnet insertion holes are provided per pole in a rotor core and permanent magnets are inserted into the magnet insertion holes,
When the permanent magnet is divided into an inner diameter side and an outer diameter side, the surface area that allows contact between the permanent magnet and the magnet insertion hole is wider on the outer diameter side than on the inner diameter side. Child. In a rotor of a permanent magnet motor in which a plurality of magnet insertion holes are provided per pole in a rotor core and permanent magnets are inserted into the magnet insertion holes,
A rotor for a permanent magnet motor, characterized in that magnet stop portions that protrude in the inner diameter direction are provided at both outer diameter side ends of the magnet insertion hole. The rotor of a permanent magnet electric motor according to claim 2, wherein the interval between the magnet stoppers is substantially the same as the circumferential length of the permanent magnet.

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