JP2007300770A - Motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor arranged to rotate a rotor by sensing leakage flux of a permanent magnet attached to the rotor by means of a magnetic detector such as a Hall IC and detecting the rotor position in which leakage flux of the permanent magnet 23 can be increased and output precision of the magnetic detector 30 is enhanced. <P>SOLUTION: In a steel plate 26 arranged on the magnetic detector 30 side while projecting from a permanent magnet 23 in the axial direction in order to secure the position of the permanent magnet 23 in the axial direction, a pawl portion for securing the permanent magnet 23 in the radial direction is eliminated. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a motor on which two rotors of an inner rotor, an outer rotor, an inner rotor, and an outer rotor are mounted.

A conventional motor is shown in FIG.
FIG. 5 shows a conventional salient pole concentrated winding type brushless motor, which includes a stator 10, a rotor 20, and a magnetic detection device 30.

  The stator 10 includes a stator yoke 11 and an outer tooth 12 extending from the stator yoke to an outer diameter. The outer tooth 12 is provided with a three-phase coil 15. Usually, the coil 15 is star-connected or delta-connected.

The rotor 20 is rotatably held outside the stator 10 and includes an outer rotor 22 and a permanent magnet 23. Further, the magnetic detection device 30 is disposed at a lower position in the axial direction of the permanent magnet 23, detects a leakage magnetic flux of the permanent magnet 23, detects the rotor position, and rotates.
The core 24 of the outer rotor 20 has a claw portion 25 for fixing the position of the permanent magnet 23 in the radial direction and the circumferential direction. A permanent magnet retaining steel plate 26 is provided on the detection device side. (For example, see Patent Document 1)
Japanese Patent Laying-Open No. 2006-14521 (page 7, FIG. 2)

  However, according to the above-described conventional technique, the permanent magnet retaining steel plate 26 also has the claw portions 25 for fixing the position of the permanent magnet 23 in the radial direction and the circumferential direction, and the leakage magnetic flux from the permanent magnet 23 is shown in FIG. As shown in Fig. 6A shows a partial cross section of the permanent magnet 23 viewed from the side of the outer teeth 12 of the stator, and FIG. 6B shows the magnitude of leakage magnetic flux from the permanent magnet 23 at the position where the magnetic detection device 30 is disposed. The lines Bop and Brp represent threshold values for the magnetic detection device 30 to detect the magnetic flux. a and b indicate the amount of deviation from the position between the poles of the permanent magnet until the magnetic detection device detects the position. If this value is large, the rotor position cannot be detected accurately, and vibration and noise during motor rotation Is an issue.

In order to solve the above-mentioned problems, the present invention has a stator core composed of a substantially annular yoke and a plurality of teeth provided on the yoke, or a winding connected to the teeth in a three-phase star or delta shape. The stator includes a stator having a plurality of coils, and a rotor that is rotatably held with respect to the stator. The teeth include an outer tooth projecting from the yoke in the outer circumferential direction and an inner tooth projecting from the yoke in the inner circumferential direction. The rotor is composed of an inner rotor facing the inner diameter side of the stator and an outer rotor side facing the outer diameter side, and a permanent magnet is located at a position facing the teeth of the inner rotor and the outer rotor. Arranged to detect the position of the rotor by the magnetic detection device and rotate the rotor. The magnetic detection device storage case has a structure attached to the lower part of the rotor. The core of the outer rotor has a claw portion for fixing the position of the permanent magnet in the radial direction and the circumferential direction. The permanent magnet has a steel plate for fixing the permanent magnet, which protrudes in the axial direction from the permanent magnet and is arranged on the magnetic detection device side to fix the position of the permanent magnet in the axial direction. It is a motor characterized by not having.

By not providing a tab on the magnet stop steel plate, the leakage magnetic flux in the vicinity of the poles of the permanent magnet 23 can be increased, and the amount of deviation in position detection of the rotor of the magnetic detection device can be reduced, resulting in vibration during motor rotation. , Noise can be reduced. (Invention of Claim 1)
Further, among the cores of the rotor in which a plurality of steel plates are laminated, the poles of the permanent magnets 23 are provided on the side of the magnetic detection device by having at least one steel plate other than the permanent magnet fastening steel plate and having no claw portion on the magnetic detection device side. It is possible to increase the leakage magnetic flux in the vicinity of the gap, and to reduce the position detection deviation amount of the rotor of the magnetic detection device, thereby reducing vibration and noise during motor rotation. (Invention of Claim 2)
Moreover, the effect similar to the said effect is acquired by comprising the steel plate for permanent magnet stop | fastening with a nonmagnetic material. (Invention of Claim 3)

  The invention according to claim 1 will be described below with reference to FIGS.

  The motor shown in FIG. 1 represents a toroidal winding brushless motor, and includes a stator 10, a rotor 20, and a magnetic detection device 30.

  The stator 10 includes a substantially annular yoke 11, a stator core 14 including outer teeth 12 projecting from the plurality of yokes 11 in the outer circumferential direction, and inner teeth 13 projecting from the yoke 11 to the inner circumferential side in the same number as the outer teeth 12. 11 includes a plurality of coils 15 connected in a three-phase star or delta shape and provided with toroidal windings. The rotor 20 is rotatably held with respect to the stator 10, and includes an inner rotor 21 that faces the inner diameter side of the stator 10, and an outer rotor 22 that faces the outer diameter side. A permanent magnet 23 is arranged at a position facing the stator teeth. The magnetic detection device 30 is mounted on a magnetic detection device wiring board 31, stored in a magnetic detection device storage case 32, and potted with a moisture-proof resin 33. Further, the core 24 of the outer rotor 22 has a claw portion 25 for fixing the position of the permanent magnet 23 in the radial direction and the circumferential direction, and protrudes in the axial direction from the permanent magnet 23 for fixing the position of the permanent magnet 23 in the axial direction. The permanent magnet retaining steel plate 26 is disposed on the side of the magnetic detection device 30, and the permanent magnet retaining steel plate 26 does not have the claw portion 25.

  2A shows a partial cross section of the outer rotor 22 as viewed from the outer teeth 12 side of the stator 10, and FIG. 2B shows the magnitude of the leakage magnetic flux from the permanent magnet 23 at the position where the magnetic detection device is disposed. The lines Bop and Brp represent threshold values at which the magnetic detection device 30 detects magnetic flux. a and b have shown the deviation | shift amount from a position between the poles of a permanent magnet until a magnetic detection apparatus detects a position.

  By not providing a tab on the magnet stop steel plate, the leakage flux near the poles of the permanent magnet is large, and the position detection deviation of the rotor of the magnetic detection device can be reduced, and vibration and noise during motor rotation can be reduced. Reduction is possible.

3 and 4 show a motor according to a second embodiment.
As shown in FIG. 3, among the cores 24 of the rotor 20 in which a plurality of steel plates are laminated, steel plates other than the permanent magnet fastening steel plates 26 and having no claw portions 25 are provided on the magnetic detection device side. Motor.

  With this configuration, the leakage magnetic flux near the poles of the permanent magnet can be increased, and the relationship between the leakage magnetic flux and the amount of magnetic detection deviation of the magnetic detection device is as shown in FIG. Also in the present invention, the magnetic detection deviations a and b can be reduced, and vibration and noise during motor rotation can be reduced.

    The invention described in claim 3 is a motor characterized in that the magnet-stopping steel plate is made of a non-magnetic material. Even in the present invention, the leakage flux of the permanent magnet is large, and the position detection deviation amount of the rotor of the magnetic detection device The vibration and noise during motor rotation can be reduced.

  The motor of the present invention is effective for a motor that requires low vibration and low noise.

(A) is a partial cross-sectional view of a motor showing an embodiment of the invention according to claim 1, (b) is a partial cross-sectional view taken along the arrow, and (c) is a partially enlarged view of the outer rotor. (A) is the fragmentary sectional view of the outer side rotor seen from the outer side teeth side, (b) is a figure which shows the change of the leakage magnetic flux of a permanent magnet. Partial sectional view of a motor showing an embodiment of the invention as claimed in claim 2 (A) is the fragmentary sectional view of the outer side rotor seen from the outer side teeth side, (b) is a figure which shows the change of the leakage magnetic flux of a permanent magnet. (A) is a partial cross-sectional view of a motor showing a conventional example, (b) is a partial cross-sectional view taken along the arrow, and (c) is an enlarged view of a portion of the outer rotor. (A) is the fragmentary sectional view of the outer side rotor seen from the outer teeth side which showed the prior art example, (b) is a figure which shows the change of the leakage magnetic flux of a permanent magnet

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Stator 11 Yoke 12 Outer teeth 13 Inner teeth 14 Stator core 15 Coil 20 Rotor 21 Inner rotor 22 Outer rotor 23 Permanent magnet 24 Core 25 Claw part 26 Steel plate for permanent magnet stop 30 Magnetic detector 31 Magnetic detector connection base 32 Magnetic detector Storage case 33 Moisture-proof resin

Claims (3)

The motor includes a stator having a substantially annular yoke and a plurality of coils provided with windings connected to the teeth in a three-phase star or delta shape in the stator core composed of a plurality of teeth provided on the yoke. The rotor is rotatably held with respect to the stator, and the teeth include outer teeth protruding from the yoke in the outer peripheral direction and inner teeth protruding from the yoke in the inner peripheral direction. An inner rotor facing the inner diameter side of the stator and an outer rotor facing the outer diameter side, and a permanent magnet is disposed at a position facing the teeth of the inner rotor and the outer rotor. The rotor is rotated by detecting the position of the magnetic sensor, has a magnetic detection device storage case for storing the magnetic detection device, The magnetic detection device storage case has a structure attached to the lower portion of the rotor. The core of the outer rotor has a claw portion for fixing the radial direction and circumferential position of the permanent magnet, and the axial position of the permanent magnet. It has a steel plate for permanent magnet fastening that protrudes in the axial direction from the permanent magnet for fixing and is disposed on the magnetic detection device side, and the steel plate for permanent magnet fastening does not have the claw portion. Motor. A motor comprising at least one steel plate not having a claw portion on a magnetic detection device side, other than the permanent magnet retaining steel plate, of a rotor core in which a plurality of steel plates are laminated. 3. The motor according to claim 1, wherein the magnet stop steel plate is made of a non-magnetic material.

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