JP2010093988A - Permanent magnet type rotating machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a permanent magnet type rotating machine which can prevent the destruction of a plurality of permanent magnets, arranged on the outer peripheral surface of a rotor core along the peripheral direction of the rotor core due to difference in linear expansion coefficient between the rotor core and the permanent magnets, without causing significant increase in cost. <P>SOLUTION: In the permanent magnet type rotating machine includes a rotor that consists of a rotor core 6, having the outer peripheral surface 6a that faces the teeth of a stator, with a space therebetween and a plurality of permanent magnets 8, arranged on the outer peripheral surface 6a of the rotor core 6 along the peripheral direction of the rotor core 6. the curvature radius Rm of the circular arc surface 8a for each permanent magnet 8, fastened to the outer peripheral surface 6a of the rotor core 6, is set larger than the curvature radius Ry of the outer peripheral surface 6a of the rotor core 6. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a permanent magnet type rotating machine applied to a synchronous motor, a generator, and the like, and in particular, a permanent magnet type rotation called a surface magnet type in which a plurality of permanent magnets are arranged on an outer peripheral surface of a rotor core. Related to the machine.

  Generally, a permanent magnet type rotating machine called a surface magnet type does not need to embed a plurality of permanent magnets inside a rotor core unlike a type called an embedded magnet type, so that it is relatively easy to manufacture. It has advantages such as. However, since the linear expansion coefficient of the permanent magnet is near zero level (positive or zero or negative close to zero) and smaller than the linear expansion coefficient of the rotor core, the copper generated by the current supplied to the excitation coil of the stator If the internal temperature of the rotating machine rises due to damage or iron loss generated in the rotor, stress is applied to the permanent magnet due to the difference between the linear expansion coefficient of the rotor core and that of the permanent magnet, and the outer periphery of the rotor core There arises a problem that the permanent magnet disposed on the surface is broken.

In order to solve this problem, the permanent magnets arranged on the outer peripheral surface of the rotor core are divided in the axial direction of the rotor to disperse the stress applied to the permanent magnets and prevent the permanent magnets from being damaged. To prevent damage to the permanent magnet by absorbing the stress applied to the permanent magnet (see Patent Document 1) and the stainless steel foam metal as an intermediate member interposed between the outer peripheral surface of the rotor core and the permanent magnet. The technique (refer patent document 2) etc. which were made to do are proposed.
JP 2007-124742 A JP 2003-153477 A

However, in the permanent magnet type rotating machine disclosed in Patent Document 1, it is necessary to bond the permanent magnet to the outer peripheral surface of the rotor core so that a divided groove is formed between the two divided permanent magnets. There is a problem that the number of assembling steps of the rotor is increased and the cost is increased.
On the other hand, in the technique disclosed in Patent Document 2, an intermediate member made of stainless steel foam metal has to be interposed between the outer peripheral surface of the rotor core and the permanent magnet, which increases the number of parts of the rotor. There is a problem of incurring cost increase.
The present invention has been made in view of the above-described problems, and a plurality of permanent magnets disposed on the outer peripheral surface of the rotor core along the circumferential direction of the rotor core are used for the linear expansion coefficient of the rotor core and the permanent magnet. It is an object of the present invention to provide a permanent magnet type rotating machine that can prevent breakage due to a difference from the linear expansion coefficient of a magnet without causing a significant increase in cost.

  In order to solve the above-described problems, a permanent magnet type rotating machine according to the present invention includes a yoke formed in an annular shape, teeth having a plurality of coil mounting portions projecting in the outer diameter direction of the yoke, and the teeth. A stator including a plurality of exciting coils mounted on the coil mounting portion, and a rotor provided rotatably with respect to the stator, the rotor separating the teeth from the gap. And a plurality of permanent magnets arranged on the outer circumferential surface of the rotor core along the circumferential direction of the rotor core. The permanent magnet has an arc surface fixed to the outer peripheral surface of the rotor core, and the arc surface has a larger radius of curvature than the outer peripheral surface of the rotor core. .

  According to the present invention, the radius of curvature of the arc surface of the permanent magnet fixed to the outer peripheral surface of the rotor core is made larger than the radius of curvature of the outer peripheral surface of the rotor core, so that the permanent magnet is fixed to the outer peripheral surface of the rotor core. A gap is formed between the circular arc surface of the permanent magnet and the outer peripheral surface of the rotor core, and these gaps absorb a difference in thermal expansion between the rotor core and the permanent magnet to apply a large stress to the permanent magnet. This can be suppressed. Therefore, in order to prevent damage to the permanent magnet due to the difference in thermal expansion between the rotor core and the permanent magnet, the permanent magnet is divided in the axial direction of the rotor, or stainless steel is provided between the outer peripheral surface of the rotor core and the permanent magnet. Since there is no need to interpose an intermediate member made of foam metal, a plurality of permanent magnets arranged on the outer circumferential surface of the rotor core along the circumferential direction of the rotor core And damage due to the difference between the linear expansion coefficient of the permanent magnet can be prevented without causing a significant increase in cost.

Hereinafter, the permanent magnet rotating machine according to the present invention will be described with reference to FIGS.
FIG. 1 is a sectional view showing a permanent magnet type rotating machine according to the first embodiment of the present invention. As shown in FIG. 1, the permanent magnet type rotating machine according to the first embodiment of the present invention is A stator 1 and a rotor 5 provided so as to be rotatable with respect to the stator 1 are provided.
The stator 1 includes a yoke 2, teeth 3 and a plurality of exciting coils 4, and the yoke 2 is formed in an annular shape. The tooth 3 has a plurality of coil mounting portions 3 a protruding in the outer diameter direction of the yoke 2 inside the yoke 2, and the exciting coil 4 is mounted on the coil mounting portion 3 a of the tooth 3.

FIG. 2 is a sectional view showing a rotor of the permanent magnet type rotating machine according to the first embodiment of the present invention. As shown in FIG. 2, the rotor 5 includes a rotor core 6, a rotor shaft 7, and A plurality of (for example, eight) permanent magnets 8 are included.
The rotor core 6 is formed by laminating a plurality of steel plates having high magnetic permeability, for example, and a rotor shaft 7 is provided at the center of the rotor core 6. The rotor core 6 has an outer peripheral surface 6a facing the teeth 3 (see FIG. 1) of the stator 1 with a gap, and a permanent magnet 8 is provided on the outer peripheral surface 6a of the rotor core 6 with the rotor. Arranged at equal intervals along the circumferential direction of the core 6. The rotor core 6 has a plurality of convex portions 6 b on the outer peripheral surface 6 a, and these convex portions 6 b are formed on the outer peripheral surface 6 a of the rotor core 6 so as to be positioned on both ends of each permanent magnet 8. Has been.

  FIG. 3 is a sectional view showing a part of the rotor of the permanent magnet type rotating machine according to the first embodiment of the present invention. As shown in FIG. 3, the permanent magnet 8 has a tensile shear bond strength of 30 MPa. It has a circular arc surface 8a that is fixed to the outer peripheral surface 6a of the rotor core 6 by an adhesive (for example, EW2020 (product name) manufactured by Sumitomo 3M Limited). Here, assuming that the radius of curvature of the outer peripheral surface 6a of the rotor core 6 is Ry, the permanent magnet 8 is injection-molded with a powdered magnet material in an arc shape so that the radius of curvature Rm of the arc surface 8a satisfies Rm> Ry. Or it is formed by sintering.

  The permanent magnet 8 includes, for example, a jig 9 shown in FIG. 4, that is, semi-cylindrical magnet holding members 10 and 11 having a plurality of magnet holding recesses 12 on the inner peripheral surface, and the circumferential direction of these magnet holding members 10 and 11. A pair of bolts 14 for fastening the magnet holding members 10 and 11 in a cylindrical shape via flanges 13 formed at both ends, and a pair of tightening nuts 15 screwed to these bolts 14 are provided. The jig 9 is bonded to the outer peripheral surface of the rotor core 6. Further, as the adhesive for adhering the permanent magnet 8 to the outer peripheral surface 6 a of the rotor core 6, it is preferable to use an adhesive having a large elasticity.

  As described above, when the radius of curvature Rm of the arc surface 8a of the permanent magnet 8 fixed to the outer peripheral surface 6a of the rotor core 6 is larger than the radius of curvature Ry of the outer peripheral surface 6a of the rotor core 6 (Rm> Ry 3), clearances 16 and 17 are formed between the outer peripheral surface 6a of the rotor core 6 and the arc surface 8a of the permanent magnet 8, and the clearances 16 and 17 make the permanent contact with the rotor core 6 as shown in FIG. It becomes possible to absorb the difference in the thermal expansion amount of the magnet 8 and to prevent a large stress from being applied to the permanent magnet 8.

  Therefore, as described above, in order to prevent the permanent magnet 8 from being damaged due to the difference in thermal expansion between the rotor core 6 and the permanent magnet 8, the permanent magnet is divided in the axial direction of the rotor, or the outer peripheral surface of the rotor core. Since there is no need to interpose an intermediate member made of stainless steel foam metal between the rotor core 6 and the permanent magnet, a plurality of members disposed on the outer circumferential surface of the rotor core 6 along the circumferential direction of the rotor core 6 It is possible to prevent the permanent magnet 8 from being damaged due to the difference between the linear expansion coefficient of the rotor core 6 and the linear expansion coefficient of the permanent magnet 8 without causing a significant increase in cost.

  Further, as in the first embodiment described above, when an adhesive having a large elasticity is used as an adhesive for bonding the permanent magnet 8 to the outer peripheral surface 6a of the rotor core 6, the outer peripheral surface 6a of the rotor core 6 and the permanent magnet are used. The permanent magnet 8 can be bonded to the outer peripheral surface 6a of the rotor core 6 without filling a large amount of adhesive in the gaps 16 and 17 formed between the circular arc surface 8a and the use of the adhesive. It is possible to prevent the amount from increasing.

In 1st Embodiment mentioned above, although the case where this invention was applied about the permanent magnet type rotary machine in which the rotor core 6 has the several convex part 6b in the outer peripheral surface 6a was shown, it is not restricted to this, As in the second embodiment shown in FIG. 5, the present invention can also be applied to a permanent magnet type rotating machine in which the rotor core 6 does not have a plurality of convex portions on the outer peripheral surface 6a.
In the above-described first embodiment, the permanent magnet disposed on the outer peripheral surface of the rotor core is a powdered magnet material that is injection-molded or sintered in an arc shape. For example, a flat permanent magnet formed by cutting into a circular arc shape may be used.

It is sectional drawing which shows the permanent magnet type rotary machine which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows the rotor of the permanent-magnet-type rotary machine which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows a part of rotor of the permanent magnet type rotary machine which concerns on the 1st Embodiment of this invention. It is a figure which shows an example of the jig | tool used when adhere | attaching a permanent magnet on the outer peripheral surface of a rotor core. It is sectional drawing which shows a part of rotor of the permanent-magnet-type rotary machine which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stator 2 Yoke 3 Teeth 3a Coil mounting part 4 Excitation coil 5 Rotor 6 Rotor core 7 Rotor shaft 8 Permanent magnet 8a Arc surface of the permanent magnet fixed to the outer peripheral surface of the rotor core 9 Outer periphery of the rotor core Jigs used when bonding a permanent magnet to the surface 10, 11 Magnet holding member 12 Magnet holding recess 13 Flange 14 Bolt 15 Nut 16, 17 Formed between the outer peripheral surface of the rotor core and the arc surface of the permanent magnet Gap

Claims (1)

An annularly formed yoke, a tooth having a plurality of coil mounting portions protruding in the outer diameter direction of the yoke inside the yoke, and a plurality of exciting coils mounted on the coil mounting portion of the tooth. A stator and a rotor provided rotatably with respect to the stator;
A rotor core having an outer peripheral surface that the rotor faces the teeth with a gap therebetween; and a plurality of permanent magnets disposed on the outer peripheral surface of the rotor core along a circumferential direction of the rotor core. A permanent magnet type rotating machine comprising:
The permanent magnet type rotating machine, wherein the permanent magnet has an arc surface fixed to the outer peripheral surface of the rotor core, and the arc surface has a larger radius of curvature than the outer peripheral surface of the rotor core.

Images