JP2001008392A - Permanent magnet rotor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of vibration or noise during operation by employing such a shape as the inner circumferential surface of a permanent magnet comes into tight contact with the outer circumferential surface of a rotor core in the vicinity of the center of a pole and a gap is provided in the vicinity of the boundary of the pole. SOLUTION: Permanent magnets 12 are arranged substantially at equal distance on the outer circumferential surface of a rotor core 11 and bonded thereto, or the permanent magnets 12 are secured by providing a nonmagnetic body to the outer circumference thereof. A recess 11a is made in the outer circumferential surface of the rotor core 11, and a gap 13 is provided between the permanent magnets 12 and the rotor core 11 in the recess 11a. A protrusion 11b is provided in the vicinity of the boundary of the pole of rotor core 11 to position the permanent magnet. According to this structure, a smooth rotary force can be obtained and vibration and noise can be lowered furthermore.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent magnet rotor in which permanent magnets are arranged on the outer peripheral surface of a substantially cylindrical rotor core.

[0002]

2. Description of the Related Art Conventionally, a permanent magnet rotor has a plurality of (usually several magnetic poles or half of the number of magnetic poles) substantially arc-shaped permanent magnets arranged substantially equally on the outer peripheral surface of a substantially cylindrical rotor core. The shape of one permanent magnet is a shape obtained by extending the shape obtained by substantially equally dividing the cylindrical shape in the rotation direction in the axial direction.
The permanent magnet is fixed to the outer peripheral surface of the rotor core with an adhesive or a tube (permanent magnet scattering prevention tube) made of a non-magnetic thin plate made of stainless steel or the like.

FIG. 7 shows a cross-sectional view of a conventional permanent magnet rotor.

A four-pole permanent magnet 62 in which four substantially arc-shaped permanent magnets 62 are arranged substantially equally on the outer peripheral surface of a substantially cylindrical rotor core 61 made of a high magnetic permeability material such as iron or laminated iron plates. It is a magnet rotor. A tube made of a nonmagnetic thin plate made of stainless steel or the like (permanent magnet scattering prevention tube) in which the rotor core 61 and the permanent magnet 62 are bonded or the outer periphery of the permanent magnet 62 is formed.
Is provided to fix the permanent magnet. The shape of the rotor core 61 is a substantially cylindrical shape centered on the rotor rotation center axis. In addition, one permanent magnet shape is a shape obtained by substantially equalizing a cylindrical shape in the rotation direction and extending straight in the axial direction. In addition, in consideration of assemblability and the like, the circumferential end faces of the permanent magnet 62 are cut with a minute width,
The edges may be chamfered or filleted.

[0005] The rotor is driven by a rotating magnetic field generated by passing a current through a winding provided on a concentrically opposed stator (not shown) via a minute air gap.
Rotate around 5 centers.

[0006]

In the above configuration, since the pulsation of the rotational force due to the positional relationship between the number of magnetic poles of the permanent magnet and the teeth of the stator is large, vibration or noise may be generated during operation.

[0007]

In order to solve the above-mentioned problems, the present invention has a shape in which the inner peripheral surface of the permanent magnet and the outer peripheral surface of the rotor core are in close contact with each other near the magnetic pole center and have a gap near the magnetic pole boundary. Further, the contact portion between the inner peripheral surface of the permanent magnet and the outer peripheral surface of the rotor core was formed to be twisted at a constant angle in the axial direction.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION
In a permanent magnet rotor in which a plurality of substantially arc-shaped permanent magnets are arranged substantially equally on the outer peripheral surface of a substantially cylindrical rotor core made of a high magnetic permeability material such as iron or laminated iron plates, And the outer peripheral surface of the rotor core are in close contact with each other near the center of the magnetic pole, and there is a gap near the magnetic pole boundary.Gap flux density is high near the magnetic pole center and low near the magnetic pole boundary due to changes in permeance. Therefore, a smooth rotational force can be obtained.

According to a second aspect of the present invention, there is provided a permanent magnet rotor in which a ring-shaped permanent magnet is arranged on the outer peripheral surface of a substantially cylindrical rotor core made of a material having high magnetic permeability such as iron or laminated iron plates. A permanent magnet rotor in which the inner peripheral surface of the permanent magnet and the outer peripheral surface of the rotor core are in close contact with each other near the magnetic pole center, and have a gap near the magnetic pole boundary. As a result, the gap magnetic flux density becomes low, so that a smooth rotational force can be obtained.

According to a third aspect of the present invention, when the number of magnetic poles of the rotor is P, the inner peripheral surface of the permanent magnet and the outer peripheral surface of the rotor core have an angle about the center of the magnetic pole and about the center of rotation of the rotor. The permanent magnet motor according to claim 1 or 2, wherein the permanent magnet motor is closely adhered within a range of 240 / P, and the vibration and noise of the motor can be reduced without substantially reducing the output of the permanent magnet.

According to a fourth aspect of the present invention, there is provided the permanent magnet rotor according to the first or second aspect, wherein the permanent magnet is isotropic and is magnetized in a state where the permanent magnet and the rotor core are integrated. In addition, the gap magnetic flux density can have a sinusoidal distribution while securing the induced voltage.

According to a fifth aspect of the present invention, there is provided the permanent magnet rotor according to the first or second aspect, wherein a contact portion between the inner peripheral surface of the permanent magnet and the outer peripheral surface of the rotor core is twisted at a constant angle in the axial direction. In addition, it is possible to reduce rotation unevenness and reduce vibration and noise of the motor.

According to a sixth aspect of the present invention, when the number of magnetic poles of the rotor is P, the contact portion between the inner peripheral surface of the permanent magnet and the outer peripheral surface of the rotor core is twisted at an angle of about 120 / P in the axial direction. 5. The permanent magnet rotor according to 5, which can cancel rotation unevenness due to phase switching and reduce motor vibration and noise, particularly when 120 ° is applied.

According to a seventh aspect of the present invention, when the least common multiple of the number of rotor poles and the number of status lots is Nc, the contact portion between the inner peripheral surface of the permanent magnet and the outer peripheral surface of the rotor core is:
The permanent magnet rotor according to claim 5, which is twisted at an angle of about 360 / Nc in the axial direction, can cancel rotational unevenness due to cogging torque, and reduce motor vibration and noise.

According to an eighth aspect of the present invention, there is provided the permanent magnet rotor according to the fifth, sixth or seventh aspect, wherein the rotor core has a projection for positioning a permanent magnet. Can be accurately set at a position where the size becomes larger.

According to a ninth aspect of the present invention, there is provided the permanent magnet rotor according to the fifth, sixth, or seventh aspect, wherein the rotor core is a laminated electromagnetic steel sheet. Can increase the productivity.

According to a tenth aspect of the present invention, the rotor core is a thin plate formed by drawing.
Alternatively, in the case of using the permanent magnet rotor according to claim 6 or 7, particularly when using a rotor having a large inner diameter, the material used can be reduced.

According to an eleventh aspect of the present invention, in the rotor core according to the fifth or sixth or seventh aspect, the rotor core is formed by hardening iron powder with a binder made of an organic substance, an inorganic substance, or a mixture thereof. It is a magnet rotor having a large degree of freedom in the shape of the rotor core, and a rotor core having a shape capable of effectively reducing motor vibration and noise can be produced. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1) FIG. 1 is a cross-sectional view of a permanent magnet rotor according to a first embodiment of the present invention.

Four substantially arc-shaped permanent magnets 12 are substantially equally arranged on the outer peripheral surface of a substantially cylindrical rotor core 11 made of a high magnetic permeability material such as iron or a laminated iron plate. 12 and the rotor core 11 or the permanent magnet 1
The permanent magnet 12 is fixed by providing a tube (permanent magnet scattering prevention tube) made of a thin plate of a non-magnetic material made of stainless steel or the like on the outer periphery of 2.

The outer periphery of the rotor core 11 is substantially circular centered on the center axis of rotation of the rotor, but has a recess 11a near the magnetic pole boundary. In the recess 11a, a gap 13 is formed between the permanent magnet 12 and the rotor core 11. is there. A protrusion 11b is provided near the magnetic pole boundary of the rotor core 11, and positions the permanent magnet.

The rotor core 11 is fixed by a rivet pin 14 or a caramase (not shown).

The portion where the permanent magnet 12 and the rotor core 11 are in close contact with each other has a central angle of about 60 ° about the center of the magnetic pole and about the rotation axis of the rotor.

According to this configuration, the permeance is high in the range of about 60 ° near the center of the magnetic pole, and the magnetic flux density at the operating point is high. Therefore, the gap magnetic flux density is high.
The presence of the gap 13 increases the equivalent air gap and lowers permeance. Therefore, since the gap magnetic flux density changes smoothly, a smooth rotational force can be obtained.

Since the inner and outer peripheral surfaces of the permanent magnet are concentric arcs, machining of the permanent magnet is easy and low cost.

The permanent magnet may have a substantially ring shape. In this case, the number of parts is reduced, and the roundness of the outer diameter of the permanent magnet is good.

(Embodiment 2) FIG. 2 is an exploded perspective view of a permanent magnet rotor according to a second embodiment of the present invention.

On the outer peripheral surface of a substantially cylindrical rotor core 21 made of laminated iron plates, four substantially arc-shaped permanent magnets 22 are arranged at substantially equal intervals.
The permanent magnet 22 is fixed by adhering or by providing a tube (permanent magnet scattering prevention tube) made of a non-magnetic thin plate made of stainless steel or the like on the outer periphery of the permanent magnet 22.

The outer periphery of the rotor core 21 has a substantially circular shape centered on the center axis of rotation of the rotor, but has a recess 21a near the magnetic pole boundary. In the recess 21a, there is a gap between the permanent magnet 22 and the rotor core 21 (see FIG. Not shown).

The rotor core 21 is formed by laminating rotor core sheets 25 punched into substantially the same shape while rotating the rotor core sheet 25 by a substantially constant angle, and rotates 30 ° over the entire length.

A protrusion 21b is provided near the magnetic pole boundary of the rotor core sheet 25b located at the center of the rotor core 21 to position the permanent magnet 22.

[0032] The rotor core 21 is fixed by means of karamase (not shown), rivet pins (not shown) and the like.

According to this configuration, the permeance is high in the range of about 60 ° where the rotor core 21 and the permanent magnet 22 are in close contact with each other, and the operating point magnetic flux density is high, so that the gap magnetic flux density is high. , The equivalent air gap increases and the permeance decreases. Since the change in the rotational direction of the gap magnetic flux density is twisted at a constant angle in the longitudinal direction, the same effect as when skew is applied to the stator or the permanent magnet is obtained. That is, uneven rotation due to the positional relationship between the stator and the rotor is canceled in the length direction, and vibration and noise are reduced.

Since the inner and outer peripheral surfaces of the permanent magnet have concentric arc shapes, machining of the permanent magnet is easy and low cost.

In this configuration, the torsion angle of the rotor core sheet is set to 30 °, which coincides with the phase switching period in the case of four poles. It is effective in reducing vibration and noise. When the stator has 6 slots or 12 slots, the cogging cycle is also 30 °, which is effective in reducing cogging. If the cycle of phase switching and the cycle of cogging do not match, the torsion angle may be selected according to the larger of the levels.

(Embodiment 3) FIG. 3 is an exploded perspective view of a permanent magnet rotor according to a third embodiment of the present invention.

The description of the same components and functions as those of the second embodiment will be omitted.

The torsion angle of the rotor core sheet is 30 in total length.
°, the torsional direction above the center in the length direction is opposite to the torsional direction below the center in the length direction. Further, the rotor core sheet 35b having the protrusions 31b is provided at the upper quarter position and the lower quarter position in the length direction.

According to this configuration, the longitudinal component of the magnetic flux passing through the gap is opposite at the upper part and the lower part from the center in the longitudinal direction, and the exciting force in the longitudinal direction can be reduced.

(Embodiment 4) FIG. 4 is an exploded perspective view of a permanent magnet rotor according to a fourth embodiment of the present invention.

A substantially ring-shaped permanent magnet 42 is disposed on the outer peripheral surface of a substantially cylindrical rotor core 41 obtained by solidifying iron powder with a binder made of an organic substance, an inorganic substance, or a mixture thereof. The permanent magnet 42 is fixed by bonding the rotor core 41 or press fitting.

The outer periphery of the rotor core 41 has a substantially circular shape centered on the center axis of rotation of the rotor, but has a concave portion 41a near the magnetic pole boundary. In the concave portion 41a, a gap is provided between the permanent magnet 42 and the rotor core 41 (see FIG. Not shown).

The cross section of the rotor core 41 in a plane perpendicular to the rotation axis is rotated by 30 ° over the entire length. The permanent magnet is magnetized to four poles.

The description of other parts and operations that are the same as in the second embodiment will be omitted.

Since the rotor core is formed by solidifying iron powder with a binder made of an organic substance, an inorganic substance, or a mixture thereof, the degree of freedom of the rotor shape is large and the precision is good. Therefore, the effect of reducing vibration and noise can be enhanced.

(Embodiment 5) FIG. 5 is an exploded perspective view of a permanent magnet rotor according to a fifth embodiment of the present invention. FIG. 6 shows a cross-sectional view of a permanent magnet rotor according to a fifth embodiment of the present invention.

The rotor core 51 is formed by drawing a thin plate, and a substantially ring-shaped permanent magnet 52 is arranged on the outer peripheral surface of the rotor core 51. The permanent magnet 52 and the rotor core 51 are bonded or press-fitted. Permanent magnet 52
Is fixed.

The outer periphery of the rotor core 51 has a substantially circular shape centered on the center axis of rotation of the rotor, but has a recess 51a near the magnetic pole boundary. In the recess 51a, a gap 53 is formed between the permanent magnet 52 and the rotor core 41. is there.

The cross section of the rotor core 51 in a plane perpendicular to the rotation axis has a shape rotated by 30 ° over the entire length. The permanent magnet is magnetized to four poles.

The length of the permanent magnet 52 is
If the length is smaller than 1, the torsion angle may be 30 °, which is equivalent to the length of the permanent magnet.

Of the other constructions and functions, the description of the same parts as in the fourth embodiment is omitted.

The permanent magnet 52 is magnetized in a state incorporated in the rotor core 51, and the magnetization state is as indicated by an arrow 55 (only one pole is shown). Due to the difference in the permeance coefficient, the gap magnetic flux density near the center of the magnetic pole becomes high and uniform, and in the portion with the gap 53 near the magnetic pole boundary,
The gap magnetic flux density becomes lower. Therefore, the gap magnetic flux density becomes pseudo sinusoidal, and the rotation unevenness is further reduced.

The number of magnetic poles of the rotor, the material of the permanent magnet,
Various modifications such as a method of holding the rotor core and the permanent magnet are possible in accordance with the present invention, and these are not excluded from the scope of the present invention.

[0054]

As is apparent from the above description, according to the first aspect of the present invention, the gap magnetic flux density is high near the magnetic pole center and the gap magnetic flux density is high near the magnetic pole boundary due to the change in permeance. Since it is lower, a smooth rotational force can be obtained. In addition, a gap can be provided between the magnetic poles of the permanent magnet, so that vibration and noise can be further reduced.

According to the second aspect of the present invention, a change in permeance causes a high gap magnetic flux density near the center of the magnetic pole and a low magnetic flux density near the boundary of the magnetic pole. Can be. Also,
Since only one permanent magnet is required, the number of parts can be reduced, and the productivity can be improved.

According to the third aspect of the present invention, the vibration and noise of the motor can be reduced without substantially lowering the output of the permanent magnet.

According to the fourth aspect of the present invention, the gap magnetic flux density can have a sinusoidal distribution while securing the induced voltage.

According to the fifth aspect of the present invention, it is possible to reduce rotational unevenness and reduce vibration and noise of the motor.

According to the invention of claim 6 of the present invention, it is possible to cancel rotational unevenness due to phase switching, particularly at the time of 120 ° conduction, and reduce motor vibration and noise.

According to the seventh aspect of the present invention, it is possible to cancel rotational unevenness due to cogging torque and reduce motor vibration and noise.

According to the invention described in claim 8 of the present invention, the permanent magnet can be accurately set at a position where the output is maximized.

According to the ninth aspect of the present invention, the rotor core sheet can be easily twisted at the time of lamination, and the productivity is improved.

According to the tenth aspect of the present invention,
In particular, when a rotor having a large inner diameter is used, the material used can be reduced.

According to the eleventh aspect of the present invention,
A rotor core having a large degree of freedom in the shape of the rotor core and capable of effectively reducing the vibration and noise of the motor can be manufactured.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a permanent magnet rotor according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of a permanent magnet rotor according to a second embodiment of the present invention.

FIG. 3 is an exploded perspective view of a permanent magnet rotor according to a third embodiment of the present invention.

FIG. 4 is an exploded perspective view of a permanent magnet rotor according to a fourth embodiment of the present invention.

FIG. 5 is an exploded perspective view of a permanent magnet rotor according to a fifth embodiment of the present invention.

FIG. 6 is a cross-sectional view of a permanent magnet rotor according to a fifth embodiment of the present invention.

FIG. 7 is a cross-sectional view of a conventional permanent magnet rotor.

[Explanation of symbols]

 11 rotor core 12 permanent magnet 13 gap

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H02K 21/14 H02K 21/14 M (72) Inventor Motoki Kondo 1006 Kadoma, Kajima, Kadoma, Osaka Matsushita Electric Industrial Incorporated (72) Inventor Hironobu Sawazaki 1006 Kazuma Kadoma, Kazuma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.F-term (reference) PP16 PP18 PP19 QB03

Claims (11)

[Claims] 1. A permanent magnet rotor in which a plurality of substantially arc-shaped permanent magnets are arranged substantially equally on an outer peripheral surface of a substantially cylindrical rotor core made of a material having high magnetic permeability such as iron or laminated iron plates. A permanent magnet rotor in which an inner peripheral surface of a permanent magnet and an outer peripheral surface of a rotor core are closely adhered near a magnetic pole center and have a gap near a magnetic pole boundary. 2. A permanent magnet rotor in which a ring-shaped permanent magnet is disposed on an outer peripheral surface of a substantially cylindrical rotor core made of a material having high magnetic permeability such as iron or laminated iron plates. A permanent magnet rotor having surfaces closely contacted near a magnetic pole center and having a gap near a magnetic pole boundary. 3. When the number of rotor magnetic poles is P, the inner peripheral surface of the permanent magnet and the outer peripheral surface of the rotor core are in close contact with each other at an angle of 240 / P about the center of the magnetic pole and about the center of rotation of the rotor. The permanent magnet motor according to claim 1 or 2, wherein 4. The permanent magnet rotor according to claim 1, wherein the permanent magnet is isotropic, and is magnetized in a state where the permanent magnet and the rotor core are integrated. 5. The permanent magnet rotor according to claim 1, wherein a contact portion between the inner peripheral surface of the permanent magnet and the outer peripheral surface of the rotor core is twisted at a constant angle in the axial direction. 6. The permanent magnet rotor according to claim 5, wherein when the number of magnetic poles of the rotor is P, a contact portion between the inner peripheral surface of the permanent magnet and the outer peripheral surface of the rotor core is twisted at an angle of about 120 / P in the axial direction. 7. The contact portion between the inner peripheral surface of the permanent magnet and the outer peripheral surface of the rotor core is twisted at an angle of about 360 / Nc in the axial direction when the least common multiple of the number of rotor magnetic poles and the number of status lots is Nc. Permanent magnet rotor. 8. The permanent magnet rotor according to claim 5, wherein the rotor core has a projection for positioning a permanent magnet. 9. The permanent magnet rotor according to claim 5, wherein the rotor core is a laminated electromagnetic steel sheet. 10. The rotor core according to claim 5, wherein the rotor core is a thin plate formed by drawing.
A permanent magnet rotor as described. 11. The permanent magnet rotor according to claim 5, wherein the rotor core is formed by hardening iron powder with a binder made of an organic substance, an inorganic substance, or a mixture thereof.