JP2007110868A - Permanent magnet type motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a permanent magnet type motor in which a skew can be formed at a permanent magnet embedded rotor, and which is not lowered in output torque, suppressed in cogging torque, and improved in vibration noise. <P>SOLUTION: The permanent magnet type motor comprises a stator 18 having a stator winding with a plurality of phases, and the permanent magnet embedded rotor 10 arranged inside the stator with a prescribed air gap between. The permanent magnet embedded rotor 10 is constituted such that: eight holes 13 for embedding are formed at a rotor core 11 that is formed by laminating almost arc-shaped rotor core sheets composed of electromagnetic steel sheets; the center of the inside diameter and the outside diameter of the embedding hole 13 and an embedded permanent magnet 12 is set on an axis of rotation; the skew is formed at the embedding hole 13; and the axial projection shape of the permanent magnet 12 is formed into a rectangular shape. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a permanent magnet type motor having a sintered magnet embedded in a rotor core, and more particularly to a structure of a permanent magnet embedded rotor.

  Conventional permanent magnet embedded rotors are generally obtained by laminating rotor core sheets having the same shape having embedded holes in the same direction and embedding a rectangular parallelepiped (flat plate) permanent magnet in the embedded holes. . Hereinafter, a conventional permanent magnet type motor will be described with reference to FIG.

  In FIG. 4, the stator core 47 of the stator 48 includes a tooth 45 and a slot 46, and the slot 46 has a plurality of windings (not shown) to apply a rotating magnetic field to the rotor 40. The rotor core 41 is formed by laminating punched electromagnetic steel plates, constitutes the magnetic path of the rotor 40 and holds the permanent magnet 42 in the embedding hole 43. The permanent magnet 42 is alternately magnetized to a plurality of magnetic poles related to the number of poles of the stator 47.

  In the permanent magnet type motor thus configured, for example, a stator 48 is provided with a U-phase, V-phase, and W-phase three-phase winding, and a rotating magnetic field is generated in the stator core 47 when energized with a predetermined phase difference. In addition, torque is generated between the magnetized rotor 40 and the permanent magnet 42 so that the rotor 40 rotates at a synchronous speed.

Also, in order to reduce noise vibration, the shape of the permanent magnet embedding hole is the same, and the shape of the elongated hole provided so as to be in contact with the end surface of the permanent magnet, the end portion of the positive electrode surface, or the end portion of the negative electrode surface Has been proposed (see, for example, Patent Document 1).
JP 2000-69695 A

  In a rotor embedded with a flat permanent magnet, the permeance coefficient (Bd / Hd) is different in each part of the magnetic pole of the permanent magnet, and the magnetomotive force of the magnet becomes non-uniform in the rotational direction. Cogging torque is generated in the rotor in relation to the arc length.

  In general, skew is often provided as a method of reducing cogging torque. However, in the conventional permanent magnet embedded rotor, it is extremely difficult to obtain an effective skew for suppressing the cogging torque. In particular, when embedding a flat sintered magnet in the rotor core, it is impossible to provide a skew other than enlarging the embedding hole. When the embedding hole is enlarged, the gap between the magnetic pole surface of the permanent magnet and the rotor core Since an air gap is generated, the permeance coefficient is lowered and the efficiency is lowered.

  The present invention solves the conventional problems, and provides a permanent magnet type motor that can provide a skew in a permanent magnet embedded rotor, suppresses cogging torque without lowering output torque, and has good vibration noise. With the goal.

In order to solve the above-mentioned problems, the present invention comprises a stator having a plurality of phases of windings in a stator core, and a permanent magnet embedded rotor disposed inside the stator via a predetermined gap, and the permanent magnet embedded rotor Is provided with a plurality of embedding holes in a rotor core formed by laminating a substantially circular rotor core sheet made of electromagnetic steel sheet, and the center of the inner and outer diameters of the embedding holes and the permanent magnet to be embedded is set on the rotation axis. Thus, the cogging torque can be suppressed.

  Moreover, the axial projection shape of the permanent magnet to be embedded may be a rectangular shape so that the embedded hole portion of the laminated rotor core has a skew. Furthermore, a permanent magnet may be embedded in multiple stages in the embedded hole formed in the axial direction, and a predetermined angle difference may be provided between the permanent magnets in each stage to ensure the skew.

  According to the permanent magnet type motor of the present invention, since the embedding hole for embedding the permanent magnet and the center of the inner and outer diameters of the permanent magnet are set on the rotation axis, the permanent magnet is skewed on the same circumferential surface. The cogging torque generated between the stator core and the stator core can be suppressed.

  In addition, since the projection shape of the permanent magnet to be embedded is a rectangular shape, it can be attached to the embedding hole having skew from the upper and lower directions, so that the output torque can be prevented from decreasing while the cogging torque is suppressed. it can.

  Further, the step-like pseudo skew in which permanent magnets are embedded in multiple stages and a predetermined angle difference is provided between the permanent magnets can also prevent the output torque from being lowered while suppressing the cogging torque.

  Furthermore, standardization can be achieved by reducing the axial projection shape of the permanent magnet to be embedded into a rectangular shape, thereby reducing the manufacturing cost.

  As described above, the cogging torque can be suppressed by providing a skew to the permanent magnet embedded rotor with an inexpensive configuration, and a motor with good vibration noise can be obtained without a decrease in output torque.

  A stator having a plurality of phases on a stator core; and a permanent magnet embedded rotor disposed inside the stator via a predetermined gap, wherein the permanent magnet embedded rotor is a substantially circular rotor core sheet made of electromagnetic steel plate. A rotor core formed by laminating a plurality of holes for burying, and setting the center of the inner and outer diameters of the burying hole and the permanent magnet to be embedded on the rotation axis, providing a skew to the hole for burying, The magnet projected in the axial direction is a rectangular shape, and is mounted in each embedding hole from the upper and lower directions.

  The permanent magnet type motor of Example 1 uses a permanent magnet embedded rotor in which a hole for embedding a permanent magnet and a center of the inner and outer diameters of the permanent magnet are set on a rotation axis.

  In FIG. 1, the stator core 17 of the stator 18 has twelve teeth 15 and slots 16, and a three-phase winding (not shown) is concentratedly wound around each of the teeth 15 subjected to insulation treatment. The rotating magnetic field is applied to the permanent magnet embedded rotor 10 by energizing with a predetermined phase difference.

  The permanent magnet embedding rotor 10 has one permanent magnet 12 embedded in one embedding hole 13 of the laminated rotor core 11 having eight embedding holes 13 at equal intervals, and alternately in the circumferential direction. It is buried and fixed to a different magnetic pole.

The permanent magnet 12 and the embedding hole 13 have concentric inner and outer diameters so as to suppress cogging torque, and their centers are set on the rotational axis. In addition, a gap portion 14 is provided between adjacent burying hole portions 13 to prevent leakage of magnetic flux, and the thickness of the outer side of the gap portion 14 is set to the burying hole portion 1.
The permanent magnet 12 is arranged as close to the outer periphery of the rotor core 11 as possible.

  In the permanent magnet embedded rotor 10 of the present invention, a rotor core sheet (electromagnetic steel plate) is laminated in the axial direction to effectively suppress cogging torque, and a skew of a predetermined angle is provided in the embedded hole 13 of the rotor core 11. .

  In order to embed one permanent magnet 12 in the embedding hole 13 provided with this skew, it is necessary to change the axial projection shape to a rectangular shape. That is, even if it is a sintered magnet, it can be embed | buried by making it the rectangular shape which narrowed the width | variety of the permanent magnet 12 more than twice the skew width (skew width in the upper and lower ends).

  This configuration is suitable for a rotor with a small skew width (for example, a rotor with a large number of magnetic poles of a permanent magnet) and a rotor with a small stacking dimension, and the inner and outer diameters of the permanent magnet and the embedding hole are concentric and rotate at the center. Since it is set on the axis, the cogging torque generated by the permanent magnet 12 and the stator core 17 can be effectively suppressed.

  As described above, the permanent magnet can be mounted even if the embedding hole is provided with a skew, so that the cogging torque can be suppressed and a permanent magnet type motor with reduced vibration noise can be obtained.

  In the first embodiment, the configuration motor of 8 poles (rotor) and 12 slots (stator) has been described. However, the present invention is not limited to this configuration.

  In Example 1, when the stacking dimension is large even when the skew width is the same, or when the skew width is large even when the stacking dimension is the same, the gap (volume) between the skewed portion of the embedding hole and the rectangular permanent magnet is increased. Increases and leads to lower output torque.

  On the other hand, the second embodiment suppresses the cogging torque while preventing the output torque from being lowered. The axial dimension of the permanent magnet is set to half of the lamination dimension of the rotor core, and the embedding hole is formed from the upper and lower directions. Buried in the part. Other configurations are the same as those of the first embodiment.

  In FIG. 2, a permanent magnet embedded rotor 20 is configured by embedding permanent magnets 22 in two vertical directions in an embedding hole 23 of a rotor core 21 provided with a skew. The two upper and lower permanent magnets 22 can obtain a step-like skew on the same circumferential surface, and can suppress the cogging torque generated between the stator cores. Further, since the gap between the two permanent magnets 22 and the skew portion can be reduced, a decrease in output torque can be prevented.

  In addition, by setting the projected shape in the axial direction of the permanent magnet 22 to a rectangular shape, it can be applied to a permanent magnet buried rotor that does not provide skew in the buried hole portion to be described later, and there is no need for skew magnetization. Since standardization is possible, manufacturing costs can be reduced.

  The permanent magnet embedded rotor of Example 1 is suitable for a permanent magnet embedded rotor having a relatively small skew width because a skew is provided in the embedded hole. On the other hand, the permanent magnet embedded rotor of Example 2 was able to mount the permanent magnet only from the upper and lower directions.

On the other hand, in the permanent magnet embedded rotor of Example 3, the blocks in which the permanent magnets are embedded in the embedded hole portions are stacked in multiple stages without providing a skew in the embedded hole portions, and the permanent magnet embedded rotors are arranged between the permanent magnets of each stage. A predetermined angular difference is provided to ensure a stair-like pseudo skew.
Similarly, the center of the inner and outer diameters of the embedding hole and the permanent magnet to be embedded is set on the rotation axis.

  The first embodiment is different from the first embodiment in that no skew is provided in the stacked embedding holes, and the rotor cores that are blocked in a plurality of stages are different from the axial dimensions of the permanent magnets that are embedded. Hereinafter, the difference will be mainly described.

  In FIG. 3, the permanent magnet embedded rotor 30 is divided into three stages by shifting a block in which the permanent magnet 32 is embedded without providing a skew in the embedded hole 33 of the rotor core 31 divided in three in the stacking direction by a predetermined angle. It is constructed by stacking.

  Since the center of the inner and outer diameters of the embedding hole and the embedding permanent magnet is set on the rotation axis as in the first embodiment, the embedded three-stage permanent magnet 32 is stepped on the same circumferential surface. -Like pseudo skew can be obtained, and cogging torque can be suppressed. Further, since no skew is provided in the embedding hole, there is basically no gap with the permanent magnet, and a decrease in output torque can be prevented.

  In addition, although the structure of 3 steps | paragraphs was demonstrated, it can implement similarly in the multistage including the other 2 steps | paragraphs. Further, the second and third embodiments may be combined, and the blocks provided with skew may be stacked in multiple stages to form a permanent magnet embedded rotor.

  As is clear from the above embodiment, the permanent magnet-embedded rotor is skewed with an inexpensive configuration by setting the embedding hole for embedding the permanent magnet and the center of the inner and outer diameters of the permanent magnet on the rotation axis. Since the cogging torque can be suppressed, a motor with good vibration noise can be obtained.

  In addition, by dividing the permanent magnet to be embedded in the axial direction, a motor with good vibration noise that suppresses cogging torque and prevents a decrease in output torque can be obtained.

  The permanent magnet type motor of the present invention is useful for a servo motor or the like that requires a high reluctance torque and high controllability and high reliability up to a high speed range.

Sectional drawing of the principal part of the permanent magnet motor in Example 1 of this invention The perspective view of the permanent-magnet embedded rotor in Example 2 of this invention Explanatory drawing of the permanent magnet embedding rotor in Example 3 of this invention Sectional view of the main part of a conventional permanent magnet motor

Explanation of symbols

10, 20, 30 Permanent magnet embedded rotor 11, 21, 31 Rotor core 12, 22, 32 Permanent magnet 13, 23, 33 Embedded hole 15 Teeth 16 Slot 17 Stator core 18 Stator

Claims (5)

A stator having a plurality of phases on a stator core; and a permanent magnet embedded rotor disposed inside the stator via a predetermined gap, wherein the permanent magnet embedded rotor is a substantially circular rotor core sheet made of an electromagnetic steel plate. A permanent magnet type motor characterized in that a plurality of embedded hole portions are provided in a rotor core formed by laminating a plurality of embedded holes, and the center of the inner and outer diameters of the embedded permanent magnet and the embedded permanent magnet is set on the rotation axis. The permanent magnet type motor according to claim 1, wherein a skew is provided in the embedded hole portion of the laminated rotor core. The permanent magnet type motor according to claim 1 or 2, wherein permanent magnets are embedded in multiple stages in the embedded holes formed in the axial direction. The permanent magnet type motor according to claim 3, wherein permanent magnets are embedded in multiple stages in the embedding hole, and a skew is secured by providing a predetermined angle difference between the permanent magnets of each stage. The permanent magnet motor according to any one of claims 2 to 4, wherein the axially projected shape of the embedded permanent magnet is a rectangular shape.