JP2014209828A - Rotor, motor, and process of manufacturing rotor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic field Lundell type rotor having improved detent torque and strong holding power, and to provide a motor and a process of manufacturing a rotor core.SOLUTION: Outside surfaces f1, f2 in a radial direction of first and second nail-shaped magnetic pole parts 22, 32 formed at first and second rotor cores 20, 30 of a rotor 4 are formed with first planes f1a, f2a and second planes f1b, f2b so as to form a convex shape with ridges La, Lb as boundaries. Thereby, it becomes possible to generate detent torque (holding power) of the same magnitude in any rotation directions of the rotor 4 (rotation axis 3).

Description

  The present invention relates to a rotor, a motor, and a method for manufacturing the rotor.

  Patent Document 1 proposes a brushless motor that employs a Landel rotor of a magnet field. This Landel type rotor is excellent in that the structure is simple and downsizing can be realized because the magnet is arranged between two rotor cores of the same material and the same shape.

Japanese Utility Model Publication No. 5-43749

  By the way, when a brushless motor is used in an apparatus that requires a position holding function, a large detent torque is required. However, a brushless motor that employs a magnet field Landell rotor has a structure in which the claw-shaped magnetic poles of the rotor core are opposed to the teeth of the stator core. For this reason, a brushless motor employing a magnet field Landell type rotor has a disadvantage that the detent torque is small and the holding force for holding the stationary motor at that position is weak.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a magnet field Landell-type rotor, motor, and rotor core manufacturing method with improved detent torque and strong holding power. It is in.

  The invention according to claim 1 has a first core base fixed to the rotary shaft, and is provided at equal intervals on the outer periphery of the first core base, and extends in the axial direction from the outer periphery. A first rotor core provided with one claw-shaped magnetic pole part and a second core base fixed to the rotating shaft are provided at equal intervals on the outer peripheral part of the second core base and extend in the axial direction from the outer peripheral part. A plurality of second claw-shaped magnetic pole portions to be provided, and each second claw-shaped magnetic pole portion is disposed between the first claw-shaped magnetic pole portions adjacent to each other in the circumferential direction; And is disposed between the first core base of the first rotor core and the second core base of the second rotor core, and each of the first claw-shaped magnetic pole portions functions as a first magnetic pole, A rotor provided with a field magnet that allows the second claw-shaped magnetic pole portion to function as a second magnetic pole. I, the direction perpendicular to the axis of the cross-sectional shape of the radially outer face of the first claw-shaped magnetic pole portions and the second claw-shaped magnetic pole portions, not a concentric circle around the central axis of the rotary shaft rotor.

  According to the first aspect of the present invention, since the distance between the surfaces of the first and second claw-shaped magnetic pole portions and the stator that are intended to rotate the rotor fluctuates, a change in the magnetic field greatly occurs with the fluctuation, It becomes a load at the time of rotation, detent torque increases, and holding force increases.

  According to a second aspect of the present invention, in the rotor according to the first aspect, the first auxiliary magnet is disposed between the first claw-shaped magnetic pole portion and the second claw-shaped magnetic pole portion that are adjacent to each other in the circumferential direction. The second auxiliary magnets are arranged on the radially inner sides of the first claw-shaped magnetic pole part and the second claw-shaped magnetic pole part, respectively.

  According to the invention described in claim 2, by providing the first and second auxiliary magnets, the magnetic flux generated between the first and second claw-shaped magnetic pole portions and the stator is increased, and the change in the magnetic field is further increased. The detent torque can be further increased.

  According to a third aspect of the present invention, in the rotor according to the first or second aspect, the cross-sectional shape in the axis orthogonal direction of the radially outer surface of the first claw-shaped magnetic pole portion and the second claw-shaped magnetic pole portion is a center position. It is the convex part shape which protrudes to a radial direction outer side, as it goes to.

  According to the third aspect of the present invention, since the cross-sectional shape is a convex shape protruding outward in the radial direction toward the center position, the change in the magnetic field is increased and the detent torque is further increased.

  According to a fourth aspect of the present invention, in the rotor according to the third aspect, the radially outer surfaces of the first claw-shaped magnetic pole part and the second claw-shaped magnetic pole part are a plurality of planes formed along the axial direction. Formed from.

  According to the fourth aspect of the present invention, since the radially outer surface is composed of a plurality of planes formed along the axial direction, the change in the magnetic field is increased and the detent torque is further increased.

  According to a fifth aspect of the present invention, in the rotor according to the first or second aspect, cogging on both sides in the circumferential direction from the circumferential center position of the radially outer surface of the first claw-shaped magnetic pole portion and the second claw-shaped magnetic pole portion. An auxiliary groove extending along the axial direction was formed at a half of the torque cycle.

According to the fifth aspect of the present invention, the torque by the auxiliary groove is increased and the detent torque is increased.
According to a sixth aspect of the present invention, in the rotor of the fifth aspect, the auxiliary grooves extending along the axial direction are formed on both sides of the first claw-shaped magnetic pole part and the second claw-shaped magnetic pole part.

According to the invention described in claim 6, the detent torque can be adjusted.
According to a seventh aspect of the present invention, in the rotor according to the fifth aspect, the auxiliary groove extending along the axial direction is formed in a central portion of the first claw-shaped magnetic pole portion and the second claw-shaped magnetic pole portion.

According to the seventh aspect of the invention, the detent torque can be adjusted.
According to an eighth aspect of the present invention, in the rotor according to the first or second aspect, cogging on both sides in the circumferential direction from the circumferential center position of the radially outer surface of the first claw-shaped magnetic pole portion and the second claw-shaped magnetic pole portion. Auxiliary grooves extending along the axial direction were formed at positions deviated from half of the torque cycle.

According to the eighth aspect of the present invention, the magnitude of the detent torque can be adjusted by forming the auxiliary grooves at the respective biased positions.
The invention described in claim 9 is the rotor according to claim 8, wherein the auxiliary grooves extending along the axial direction are formed on both sides of the first claw-shaped magnetic pole part and the second claw-shaped magnetic pole part.

According to the ninth aspect of the invention, the detent torque can be adjusted.
According to a tenth aspect of the present invention, in the rotor according to the eighth aspect, the auxiliary groove extending along the axial direction is formed in a central portion of the first claw-shaped magnetic pole portion and the second claw-shaped magnetic pole portion.

According to the invention described in claim 10, the detent torque can be adjusted.
According to an eleventh aspect of the present invention, in the rotor according to any one of the eighth to tenth aspects, each position shifted from a half position of the cogging torque period is a half position of the cogging torque period. Auxiliary grooves were formed at symmetrical positions on both sides in the circumferential direction.

According to the eleventh aspect of the present invention, the magnitude of the detent torque can be adjusted by forming the auxiliary grooves at symmetrical positions.
A twelfth aspect of the present invention is the rotor according to the first or second aspect, wherein the cross-sectional shape in the axis orthogonal direction of the radially outer surfaces of the first claw-shaped magnetic pole part and the second claw-shaped magnetic pole part is a circumferential direction. The outer diameter was continuously shortened from one end to the other end.

  According to the twelfth aspect of the present invention, since the outer diameter of the radially outer surface is continuously shortened from one end portion in the circumferential direction toward the other end portion, The detent torque for rotation toward the one end side can be made larger than the detent torque for rotation.

  The invention according to a thirteenth aspect is the rotor according to the twelfth aspect, wherein the cross-sectional shape of the radially outer surface in the axis-orthogonal direction is such that an air gap at one end portion in the circumferential direction is α, and the other in the circumferential direction. When the air gap at the end is β, 1.0 <α / β ≦ 5.0.

According to the thirteenth aspect of the present invention, the detent torque with respect to the rotation toward the one end can be increased without greatly reducing the output.
According to a fourteenth aspect of the present invention, in the rotor according to the twelfth or thirteenth aspect, a cross-sectional shape in the axis orthogonal direction of the radially outer surface is a curved shape.

According to the fourteenth aspect of the present invention, the holding force (detent torque) against the rotation toward the one end can be smoothly changed with respect to the rotation angle.
According to a fifteenth aspect of the present invention, in the rotor according to the first or second aspect, the cross-sectional shape of the first claw-shaped magnetic pole portion and the second claw-shaped magnetic pole portion in the axially orthogonal direction of the radially outer surface is a circumferential direction. The outer diameter was formed so as to be shortened step by step from one end to the other end.

  According to the invention of claim 15, the radially outer side surface is formed such that the outer diameter decreases stepwise as it goes from one end portion in the circumferential direction to the other end portion. The detent torque for the rotation toward the one end can be made larger than the detent torque for the rotation toward the side.

  According to a sixteenth aspect of the present invention, in the rotor according to the fifteenth aspect, the cross-sectional shape of the radially outer surface in the axis-orthogonal direction is formed by two arc surfaces with a central position as a boundary. The outer diameter of the arc surface on the end side is formed shorter than the outer diameter of the arc surface on the one end portion side in the circumferential direction.

According to the sixteenth aspect of the present invention, the detent torque with respect to the rotation toward the one end can be increased.
According to a seventeenth aspect of the present invention, there is provided a plurality of first core bases that have a first core base that is fixed to the rotating shaft and that are provided at equal intervals on the outer peripheral portion of the first core base and that extend in the axial direction from the outer peripheral portion. A first rotor core provided with one claw-shaped magnetic pole part and a second core base fixed to the rotating shaft are provided at equal intervals on the outer peripheral part of the second core base and extend in the axial direction from the outer peripheral part. A plurality of second claw-shaped magnetic pole portions to be provided, and each second claw-shaped magnetic pole portion is disposed between the first claw-shaped magnetic pole portions adjacent to each other in the circumferential direction; And is disposed between the first core base of the first rotor core and the second core base of the second rotor core, and each of the first claw-shaped magnetic pole portions functions as a first magnetic pole, A rotor provided with a field magnet that causes the second claw-shaped magnetic pole portion to function as a second magnetic pole A retaining force forming member is fitted to the radially outer surface of the first claw-shaped magnetic pole portion and the second claw-shaped magnetic pole portion alternately arranged in the circumferential direction, and the radially outer surface of the retaining force forming member is Thus, the cross-sectional shape in the direction perpendicular to the axis of the area surface facing the radially outer surface of the first claw-shaped magnetic pole portion and the second claw-shaped magnetic pole portion is not concentric with the central axis of the rotating shaft as the center. Formed.

  According to the seventeenth aspect of the present invention, when the rotor is about to rotate only by fitting the holding force forming member, the distance between the region surface and the stator varies, and accordingly, the magnetic field changes with the variation. Is generated and becomes a load during rotation, detent torque increases, and holding force increases.

  According to an eighteenth aspect of the present invention, in the rotor according to the seventeenth aspect, a first auxiliary magnet is disposed between the first claw-shaped magnetic pole portion and the second claw-shaped magnetic pole portion that are adjacent to each other in the circumferential direction. The second auxiliary magnets are arranged on the radially inner sides of the first claw-shaped magnetic pole part and the second claw-shaped magnetic pole part, respectively.

  According to the invention described in claim 18, by providing the first and second auxiliary magnets, the magnetic flux generated between the first and second claw-shaped magnetic pole portions and the stator is increased, and the change of the magnetic field is further increased. The detent torque can be further increased. Further, since the first auxiliary magnet is pressed by the holding force forming member, it is not popped out by the centrifugal force due to the rotation.

  According to a nineteenth aspect of the present invention, in the rotor according to the seventeenth or eighteenth aspect, there is a radially outer surface of the holding force forming member and a radially outer surface of the first claw-shaped magnetic pole portion and the second claw-shaped magnetic pole portion. On each of the region surfaces facing the surface, auxiliary grooves or ridges extending along the axial direction were formed from the circumferential center position of the region surface to a position half the period of cogging torque on both sides in the circumferential direction.

According to the nineteenth aspect, the detent torque can be increased.
The invention according to claim 20 has a first core base fixed to the rotating shaft, and is provided at equal intervals on the outer peripheral portion of the first core base and extends in the axial direction from the outer peripheral portion. A first rotor core provided with one claw-shaped magnetic pole part and a second core base fixed to the rotating shaft are provided at equal intervals on the outer peripheral part of the second core base and extend in the axial direction from the outer peripheral part. A plurality of second claw-shaped magnetic pole portions to be provided, and each second claw-shaped magnetic pole portion is disposed between the first claw-shaped magnetic pole portions adjacent to each other in the circumferential direction; And is disposed between the first core base of the first rotor core and the second core base of the second rotor core, and each of the first claw-shaped magnetic pole portions functions as a first magnetic pole, A rotor provided with a field magnet that causes the second claw-shaped magnetic pole portion to function as a second magnetic pole The first plate is disposed on the outer surface in the axial direction of the first core base, and is disposed on the second plate on the outer surface in the axial direction of the second core base, and the first plate and the second plate The radially outer peripheral edge portions were connected by a holding force forming bar that covers a part of the radially outer surface of the first and second claw-shaped magnetic pole portions along the axial direction.

  According to the twentieth aspect of the present invention, when the holding force forming bar is disposed on the radially outer surface of the first and second claw-shaped magnetic pole portions, when the rotor tries to rotate, the radially outer surface and the stator The interval between and apparently fluctuates. For this reason, the magnetic field greatly changes with the fluctuation, resulting in a load during rotation, detent torque increases, and holding force increases.

  According to a twenty-first aspect of the invention, in the rotor according to the twentieth aspect, the holding force forming bar is circumferentially arranged from a circumferential central position of a radially outer surface of the first claw-shaped magnetic pole portion and the second claw-shaped magnetic pole portion. A pair of the holding force forming bars extending along the axial direction at a position half the period of the cogging torque on both sides in the direction.

According to the twenty-first aspect, the detent torque can be increased.
The invention according to claim 22 is a motor comprising the rotor according to any one of claims 1 to 21.

According to the twenty-second aspect of the present invention, a motor having a large detent torque can be realized.
According to a twenty-third aspect of the present invention, in the motor according to the twenty-second aspect, the motor is a two-pole / three-slot brushless motor.

  According to the invention of claim 23, when one claw-shaped magnetic pole portion faces the teeth, the other magnetic pole portion is in a positional relationship facing between the teeth, and the stop position is stabilized and the detent torque is increased. To do.

  A twenty-fourth aspect of the present invention is the rotor manufacturing method according to any one of the fifth to eleventh aspects, wherein the electromagnetic steel sheet is punched and a through-hole and a disk for fixing the rotating shaft through are fixed. After punching and forming the shape-shaped core base and the portion extending in the radial direction from the core base, one side surface of the portion extending in the radial direction from the core base is plastically deformed to form an auxiliary groove, and the auxiliary groove is formed. Thereafter, the first and second rotor cores were formed by bending the portion extending in the radial direction in the axial direction.

  According to the invention of claim 24, the first and second rotor cores of the rotor having a large detent torque can be manufactured at low cost.

  ADVANTAGE OF THE INVENTION According to this invention, the detent torque can be improved and the magnetic field Randell type rotor with strong holding power can be provided. ADVANTAGE OF THE INVENTION According to this invention, the detent torque can be improved and the magnetic field Randell type rotor with strong holding power can be provided.

Sectional drawing seen from the axial direction of the brushless motor of 1st Embodiment. Similarly, the perspective view which looked at the rotor from the axial direction. Similarly, the front view which looked at the rotor from the axial direction. Similarly, the aob line combination sectional view of Drawing 3. Similarly, the exploded perspective view of a rotor. The front view which looked at the rotor which shows another example of 1st Embodiment from the axial direction. It is a figure which shows the other example of 1st Embodiment, Comprising: (a) is a perspective view of the rotor seen from the 1st rotor core side, (b) is a perspective view of the rotor seen from the 2nd rotor core side. Sectional drawing seen from the axial direction of the brushless motor of 2nd Embodiment. Similarly, the perspective view which looked at the rotor from the axial direction. Similarly, the front view which looked at the rotor from the axial direction. Similarly, the aob line combination sectional view of FIG. Similarly, the exploded perspective view of a rotor. Similarly, it is a figure which shows the formation method of a rotor, Comprising: (a) is a figure before claw-shaped magnetic pole part formation, (b) is a figure after claw-shaped magnetic pole part formation. Similarly, the figure which shows the relationship of each detent torque. It is a figure which shows another example of 2nd Embodiment, Comprising: (a) is a perspective view of the rotor seen from the 1st rotor core side, (b) is a perspective view of the rotor seen from the 2nd rotor core side. The front view which looked at the rotor of 3rd Embodiment from the axial direction. The figure which shows the relationship of each detent torque of 3rd Embodiment. The perspective view which looked at the rotor of 4th Embodiment from the axial direction. Similarly, the front view which looked at the rotor from the axial direction. Similarly, the aob line combination sectional view of FIG. Similarly, the exploded perspective view of a rotor. Sectional drawing of the rotor which shows another example of 4th Embodiment. The perspective view which looked at the rotor which shows another example of 4th Embodiment from the axial direction. Sectional drawing seen from the axial direction of the brushless motor of 5th Embodiment. Similarly, the principal part front view which looked at the rotor from the axial direction. Similarly, the aob line combined sectional view of FIG. Similarly, the exploded perspective view of the rotor which abbreviate | omitted the interpole auxiliary magnet and the back side auxiliary magnet. Similarly, (a) is a perspective view of the rotor viewed from the first rotor core side, and (b) is a perspective view of the rotor viewed from the second rotor core side. Similarly, the figure which shows the relationship of a detent torque. The principal part front view which looked at the rotor which shows another example of 5th Embodiment from the axial direction. The perspective view which looked at the rotor of 6th Embodiment from the axial direction. Similarly, the front view which looked at the rotor from the axial direction. Similarly, the aob line combination sectional view of Drawing 32. Similarly, the exploded perspective view of the rotor for demonstrating a holding force formation member. Similarly, the exploded perspective view of the rotor which abbreviate | omitted the interpole auxiliary magnet, the back side auxiliary magnet, and the holding force formation member. The perspective view which looked at the rotor which shows another example of 6th Embodiment from the axial direction. Similarly, the exploded perspective view of the rotor for demonstrating a holding force formation member. The perspective view which looked at the rotor of 7th Embodiment from the axial direction. Similarly, the exploded perspective view of the rotor for demonstrating a holding force formation member. Similarly, the front view which looked at the rotor from the axial direction. The perspective view which looked at the rotor which shows another example of 7th Embodiment from the axial direction. Similarly, the exploded perspective view of the rotor for demonstrating a holding force formation member.

(First embodiment)
A first embodiment in which the present invention is embodied in a brushless motor will be described below with reference to FIGS.

  As shown in FIG. 1, a brushless motor M has a stator 2 fixed to an inner peripheral surface of a motor housing 1, and a rotor 4 that is fixed to a rotating shaft 3 and rotates integrally with the rotating shaft 3 inside the stator 2. Is arranged.

(Stator 2)
The stator 2 has a cylindrical stator core 10, and the outer peripheral surface of the stator core 10 is fixed to the motor housing 1. Inside the stator core 10, a plurality of teeth 11 formed along the axial direction and arranged at equal pitches in the circumferential direction are formed extending inward in the radial direction. Each tooth 11 is a T-shaped tooth, and an inner circumferential surface 11 a in the radial direction is an arc surface obtained by extending a concentric arc centering on the central axis O of the rotating shaft 3 in the axial direction.

  A stator side slot 12 is formed between the teeth 11. In the present embodiment, the number of teeth 11 is twelve, and the number of stator side slots 12 is twelve, which is the same as the number of teeth 11. Around the 12 teeth 11, a three-phase winding, that is, a U-phase winding 13u, a V-phase winding 13v, and a W-phase wire 13w are wound in order in a concentrated manner in the circumferential direction.

  Then, a three-phase power supply voltage is applied to each of the wound phase windings 13u, 13v, and 13w to form a rotating magnetic field in the stator 2, and the rotor 4 fixed to the rotating shaft 3 disposed inside the stator 2 is provided. Are rotated in the forward direction (clockwise direction in FIG. 1) and in the reverse direction (rotated in the counterclockwise direction in FIG. 1).

  As shown in FIGS. 2 to 5, the rotor 4 disposed inside the stator 2 includes first and second rotor cores 20 and 30 and an annular magnet 40 as a field magnet (see FIGS. 4 and 5). With.

(First rotor core 20)
As shown in FIG. 5, a plurality of first rotor cores 20 are formed at equal intervals on the outer peripheral portion of a first core base 21 formed in a substantially disc shape having a through hole 20 a through which the rotary shaft 3 is inserted and fixed. In the embodiment, four first claw-shaped magnetic pole portions 22 protrude outward in the radial direction and extend in the axial direction.

  Both end surfaces 22a and 22b in the circumferential direction of the first claw-shaped magnetic pole portion 22 are flat surfaces extending in the radial direction (not inclined with respect to the radial direction when viewed from the axial direction). The angle in the circumferential direction of each first claw-shaped magnetic pole portion 22, that is, the angle between the circumferential end surfaces 22a and 22b is set smaller than the angle of the gap between the first claw-shaped magnetic pole portions 22 adjacent in the circumferential direction. Has been.

Further, as shown in FIG. 2, the radially outer surface f1 of the first claw-shaped magnetic pole part 22 has two planes, a first plane f1a and a second plane f1b.
More specifically, as shown in FIG. 3, it is the radially outer surface f1 of the first claw-shaped magnetic pole part 22, and the intermediate position in the circumferential direction of the first claw-shaped magnetic pole part 22 from the central axis O of the rotating shaft 3. A point that intersects the center line L1 of the passing straight line is defined as a vertex P1. A line extending from the apex P1 in the axial direction in parallel with the central axis O of the rotary shaft 3 is defined as a ridge line La (see FIGS. 2 and 5). With this ridge line La as a boundary, they are cut out at the same inclination angle θa in the clockwise direction and the counterclockwise direction and inward in the radial direction. Then, the plane cut out in the clockwise direction with the ridge line La as the boundary is defined as the first plane f1a, and conversely, the plane cut out in the counterclockwise direction with the ridge line La as the boundary is defined as the second plane f1b. To do.

  Accordingly, the radially outer side surface f1 of the first claw-shaped magnetic pole portion 22 has a ridgeline La as the topmost portion closest to the stator 2, and moves away from the stator 2 toward the clockwise direction and the counterclockwise direction from the ridgeline La. It becomes the convex part shape which spaces apart. That is, the radial outer surface f <b> 1 of the first claw-shaped magnetic pole portion 22 does not have a concentric circular shape with the cross-sectional shape perpendicular to the axis centering on the central axis O of the rotation shaft 3.

(Second rotor core 30)
As shown in FIG. 5, the second rotor core 30 has the same shape as the first rotor core 20, and is formed on the outer peripheral portion of the substantially disk-shaped second core base 31 having a through hole 30 a through which the rotary shaft 3 is inserted and fixed. At the same interval, four second claw-shaped magnetic pole portions 32 protrude radially outward and extend in the axial direction.

  Both end surfaces 32a and 32b in the circumferential direction of the second claw-shaped magnetic pole portion 32 are flat surfaces extending in the radial direction. The angle in the circumferential direction of each second claw-shaped magnetic pole portion 32, that is, the angle between the circumferential end surfaces 32a and 32b is set smaller than the angle of the gap between the second claw-shaped magnetic pole portions 32 adjacent in the circumferential direction. Has been.

Further, as shown in FIG. 2, the radially outer surface f2 of the second claw-shaped magnetic pole portion 32 has two planes, a first plane f2a and a second plane f2b.
More specifically, as shown in FIG. 3, it is the radially outer surface f2 of the second claw-shaped magnetic pole portion 32, and the intermediate position in the circumferential direction of the second claw-shaped magnetic pole portion 32 from the central axis O of the rotation shaft 3. A point that intersects the center line L2 of the passing straight line is defined as a vertex P2. A line extending from the apex P2 in the axial direction in parallel with the central axis O of the rotary shaft 3 is defined as a ridge line Lb (see FIGS. 2 and 5). With this ridge line Lb as a boundary, they are cut out at the same inclination angle θb (= θa) in the clockwise direction and the counterclockwise direction, and radially inward. A plane cut out in the clockwise direction with the ridge line Lb as a boundary is defined as a first plane f2a, and conversely, a plane cut out in the counterclockwise direction with the ridge line Lb as a boundary is defined as a second plane f2b.

  Accordingly, the radially outer side surface f2 of the second claw-shaped magnetic pole portion 32 has a ridge line Lb closest to the stator 2 and the distance from the stator 2 toward the clockwise direction and the counterclockwise direction from the ridge line Lb. It becomes the convex part shape which spaces apart. That is, the radial outer surface f <b> 2 of the second claw-shaped magnetic pole part 32 does not have a concentric circular shape with the axial orthogonal cross-section centered on the central axis O of the rotation shaft 3.

  The second rotor core 30 is disposed between the first claw-shaped magnetic pole portions 22 corresponding to the second claw-shaped magnetic pole portions 32 respectively. At this time, the second rotor core 30 is attached to the first rotor core 20 such that the annular magnet 40 (see FIG. 4) is disposed (sandwiched) between the first core base 21 and the second core base 31 in the axial direction. It is assembled against.

  Specifically, as shown in FIG. 4, the annular magnet 40 includes a surface (opposing surface 21 a) of the first core base 21 on the second core base 31 side and a surface of the second core base 31 on the first core base 21 side. It is sandwiched between (opposing surfaces 31a).

  At this time, one circumferential end surface 22a of the first claw-shaped magnetic pole portion 22 and the other circumferential end surface 32b of the second claw-shaped magnetic pole portion 32 are formed so as to be parallel along the axial direction. The gap between the surfaces 22a and 32b is formed so as to be substantially linear along the axial direction. Further, the other circumferential end surface 22b of the first claw-shaped magnetic pole portion 22 and one circumferential end surface 32a of the second claw-shaped magnetic pole portion 32 are formed so as to be parallel along the axial direction. The gap between 22b and 32a is formed so as to be substantially linear along the axial direction.

As shown in FIGS. 4 and 5, the annular magnet 40 sandwiched between the first rotor core 20 and the second rotor core 30 is an annular plate-shaped permanent magnet made of a neodymium magnet.
As shown in FIG. 5, the annular magnet 40 has a through hole 41 penetrating the rotating shaft 3 at the center position. Then, one side surface 40 a of the annular magnet 40 abuts the opposing surface 21 a of the first core base 21 and the other side surface 40 b of the annular magnet 40 contacts the opposing surface 31 a of the second core base 31, respectively. Is sandwiched and fixed between the first rotor core 20 and the second rotor core 30.

The outer diameter of the annular magnet 40 is set to coincide with the outer diameters of the first and second core bases 21 and 31, and the thickness is set to a predetermined thickness.
That is, as shown in FIG. 4, when the annular magnet 40 is disposed between the first rotor core 20 and the second rotor core 30, the tip surface 22 c of the first claw-shaped magnetic pole portion 22 is opposite to the second core base 31. The facing surface 31b is flush with the tip surface 32c of the second claw-shaped magnetic pole portion 32 and the anti-opposing surface 21b of the first core base 21 is flush.

  As shown in FIG. 4, the annular magnet 40 is magnetized in the axial direction so that the first rotor core 20 side becomes an N pole (first magnetic pole) and the second rotor core 30 side becomes an S pole (second magnetic pole). Is magnetized. Therefore, the first claw-shaped magnetic pole portion 22 of the first rotor core 20 functions as an N pole (first magnetic pole) by the annular magnet 40, and the second claw-shaped magnetic pole portion 32 of the second rotor core 30 functions as an S pole (second magnetic pole). Function as a magnetic pole).

  Therefore, the rotor 4 of the present embodiment is a so-called Landel type rotor using the annular magnet 40. In the rotor 4, the first claw-shaped magnetic pole portions 22 that are N poles and the second claw-shaped magnetic pole portions 32 that are S poles are alternately arranged in the circumferential direction, and the number of magnetic poles is eight.

Next, the operation of the embodiment configured as described above will be described below.
In the brushless motor M, when a three-phase power supply voltage is applied to the phase windings 13u, 13v, 13w wound around the teeth 11 of the stator core 10 to form a rotating magnetic field on the stator 2, The rotor 4 fixed to the rotating shaft 3 disposed in the position rotates based on the rotating magnetic field.

  When the application of the three-phase power supply voltage to each phase winding 13u, 13v, 13w is stopped, the rotating magnetic field disappears and the rotor 4 stops rotating. At this time, the rotor 4 flows from the teeth 11 of the stator core 10 into the magnetic flux that the first claw-shaped magnetic pole portion 22 of the first rotor core 20 flows into the teeth 11 of the stator core 10 and the second claw-shaped magnetic pole portion 32 of the second rotor core 30. The magnetic flux stops at the rotation position where the stable state is obtained.

  That is, the ridge line La (ridge line Lb) on the radially outer surface f1 (radial outer surface f2) of any one of the first and second claw-shaped magnetic pole portions 22 and 32 is radially inward of the teeth 11 facing each other. This is a case where the circumferential surface 11a is located at an intermediate position in the circumferential direction. FIG. 1 shows a case where the ridge line La on the radially outer surface f1 of the first claw-shaped magnetic pole portion 22 is located on the radially inner peripheral surface 11a of the teeth 11 facing each other and at an intermediate position in the circumferential direction. . In this case, since the brushless motor M is a motor with the rotor 4 having 8 poles and the stator 2 having 12 throttles, the ridge line Lb on the radially outer surface f2 of the second claw-shaped magnetic pole portion 32 is formed between the teeth 11 and 11. Located in the middle position.

  In this state, when the rotor 4 (rotating shaft 3) is rotated, the radially outer surface f1 of the first claw-shaped magnetic pole portion 22 is circumferential in the circumferential direction with respect to the radially inner peripheral surface 11a of the teeth 11 facing each other. Moving.

  At this time, since the radially outer surfaces f1 and f2 of the first and second claw-shaped magnetic pole portions 22 and 32 are formed in a convex shape with the ridgelines La and Lb as a boundary, a change in magnetic flux accompanying the movement is It is much larger than the radially outer surface of the first claw-shaped magnetic pole portion that is a concentric circle centered on the same central axis of the rotation shaft 3 as the radially inner peripheral surface 11a of the tooth 11.

  Since the holding force (detent torque) for returning the magnetic flux to a stable state is relative to the change of the magnetic field, in this case, since the change of the magnetic field is very large, the holding force (detent torque) increases.

  Moreover, the radially outer surfaces f1 and f2 of the first and second claw-shaped magnetic pole portions 22 and 32 are first planes f1a and f2a having the same inclination angles θa and θb symmetrically on both sides in the circumferential direction with respect to the ridgelines La and Lb. And the second planes f1b and f2b are formed, the same holding force (detent torque) is obtained in any rotation direction of the rotor 4 (rotating shaft 3).

Next, the effect of the said embodiment is described below.
(1) According to the present embodiment, since the radially outer surfaces f1 and f2 of the first and second claw-shaped magnetic pole portions 22 and 32 are formed in a convex shape with the ridgelines La and Lb as boundaries, the detent torque is reduced. The holding force of the brushless motor M in a stationary state can be increased.

  (2) According to the present embodiment, the radially outer surfaces f1 and f2 of the first and second claw-shaped magnetic pole portions 22 and 32 have the same inclination angle θa, symmetrically on both sides in the circumferential direction with the ridgelines La and Lb as boundaries. First planes f1a and f2a of θb and second planes f1b and f2b were formed. Therefore, the same detent torque (holding force) can be generated in any rotation direction of the rotor 4 (rotating shaft 3).

Moreover, in the brushless motor M that can rotate forward and backward, there is no period fluctuation of the cogging torque that occurs between forward rotation and reverse rotation.
In addition, you may change the said 1st Embodiment as follows.

  In the present embodiment, convex radial outer surfaces f1, f2 having a first plane and a second plane are formed. As shown in FIG. 6, the radially outer surfaces f1 and f2 are formed by forming convex shapes including the first planes f1a and f2a, the second planes f1b and f2b, and the third planes f1c and f2c. May be. In short, if the shape of the first and second claw-shaped magnetic pole portions 22 and 32 viewed from the axial direction of the radially outer surfaces f1 and f2 is a surface that does not become a concentric circle centered on the central axis O of the rotating shaft 3. Good.

  As shown in FIGS. 7 (a) and 7 (b), in the rotor 4, an inter-pole auxiliary magnet 51 is interposed between the first claw-shaped magnetic pole portion 22 and the second claw-shaped magnetic pole portion 32, and the first and You may implement by interposing the back side auxiliary magnets 52 and 53 in the radial direction inner side of the 2nd nail | claw-shaped magnetic pole parts 22 and 32, respectively.

  Here, the magnetization direction of the inter-magnetic pole auxiliary magnet 51 is magnetized so that the first claw-shaped magnetic pole portion 22 side is an N pole and the second claw-shaped magnetic pole portion 32 side is an S pole. On the other hand, the back auxiliary magnet 52 shown in FIG. 7A is magnetized so that the first core base 21 side has an N pole and the second claw-shaped magnetic pole portion 32 side has an S pole. Further, the back auxiliary magnet 53 shown in FIG. 7B is magnetized so that the second core base 31 side is an S pole and the first claw-shaped magnetic pole portion 22 side is an N pole.

  Thus, by providing these auxiliary magnets 51, 52, 53, the magnetic flux generated between the first and second claw-shaped magnetic pole portions 22, 32 and the teeth 11 of the stator core 10 is increased, and the change of the magnetic field is further increased. The detent torque can be increased by increasing the detent torque.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS.
This embodiment is characterized by the radially outer surfaces f1, f2 of the first and second claw-shaped magnetic pole portions 22, 32 shown in the first embodiment. Therefore, the characteristic portion will be described in detail, and the detailed description of the portions common to the first embodiment will be omitted for convenience of description.

  As shown in FIG. 8, in the brushless motor M of the present embodiment, a stator 2 is fixed to the inner peripheral surface of the motor housing 1, and the stator 2 is fixed to the rotating shaft 3 and integrated with the rotating shaft 3 inside the stator 2. A rotating rotor 4 is provided.

  The stator 2 has a stator core 10, and twelve teeth 11 extend from the inside of the stator core 10. Each tooth 11 is a T-shaped tooth, and its radially inner circumferential surface 11 a is an arc surface in which a concentric arc extends in the axial direction around the central axis O of the rotating shaft 3. In addition, a three-phase winding, that is, a U-phase winding 13u, a V-phase winding 13v, and a W-phase wire 13w are sequentially wound around the twelve teeth 11 by concentrated winding.

Then, a three-phase power supply voltage is applied to each of the wound phase windings 13u, 13v, 13w to form a rotating magnetic field in the stator 2.
As shown in FIGS. 9 to 12, the rotor 4 disposed inside the stator 2 includes first and second rotor cores 20 and 30 and an annular magnet 40 (see FIGS. 11 and 12).

  As shown in FIG. 12, the first rotor core 20 has four first claw-shaped magnetic pole portions 22 projecting radially outward at equal intervals on the outer periphery of a first core base 21 formed in a substantially disc shape. At the same time, it extends in the axial direction.

  The angle in the circumferential direction of each first claw-shaped magnetic pole portion 22, that is, the angle between the circumferential end surfaces 22a and 22b is set smaller than the angle of the gap between the first claw-shaped magnetic pole portions 22 adjacent in the circumferential direction. Has been.

  In addition, the radially outer surface f1 of the first claw-shaped magnetic pole portion 22 has a concentric circular arc surface whose center is perpendicular to the central axis O of the rotating shaft 3, and the radial outer surface f1 The first auxiliary groove 25 and the second auxiliary groove 26 are provided.

  More specifically, as shown in FIG. 10, it is the radially outer surface f1 of the first claw-shaped magnetic pole part 22, and the intermediate position in the circumferential direction of the first claw-shaped magnetic pole part 22 from the central axis O of the rotating shaft 3. A straight line passing through is defined as a center line L1. Straight lines extending from the central axis located at the angle θ1 in the clockwise direction and the counterclockwise direction with respect to the center line L1 are defined as a first straight line L1a and a second straight line L1b, respectively.

Here, the angle θ1 was obtained using the following arithmetic expression based on the period of cogging torque (angle φ).
θ1 = (1/2 + n) · φ
Note that n is an integer, and in this embodiment, n = 0.

The period φ of the cogging torque is generally a value obtained by dividing 360 degrees by the least common multiple of the number of magnetic poles of the rotor 4 and the number of slots of the stator 2.
At this time, since the number of magnetic poles of the rotor 4 is 8 and the number of slots of the stator 2 is 12, the least common multiple is 24. The period φ of the cogging torque is 15 (= 360/24) degrees.

Accordingly, the angle θ1 is 7.5 (= 15/2) degrees.
Then, on the radially outer surface f1, the first straight line L1a and the second straight line L1b that are displaced by 7.5 degrees in the clockwise direction and the counterclockwise direction around the center line L1 are constant as the intermediate positions in the circumferential direction. Grooves having a width of 1 mm are recessed in the axial direction.

  And the groove | channel which makes the 1st straight line L1a the circumferential direction intermediate position is the 1st auxiliary groove 25, and the groove | channel which makes the 2nd straight line L1b the circumferential direction intermediate position is the 2nd auxiliary groove 26 on the contrary. Accordingly, the angle formed by the first auxiliary groove 25 and the second auxiliary groove 26 about the central axis O of the rotation shaft 3 coincides with the cogging torque period φ (= 15 degrees).

  That is, the angle formed by the center line L1 and the first straight line L1a and the angle formed by the center line L1 and the second straight line L1b are both a half period (= 7.5 degrees) of the period φ of the cogging torque. The second auxiliary groove 26 is formed at a symmetrical position with the center line L1 as the axis of symmetry.

  The first and second auxiliary grooves 25, 26 are formed in a U-shaped cross section in the direction perpendicular to the axis, the bottom surfaces 25 a, 26 a are flat, and are perpendicular to the side surfaces extending from the radially outer side from both sides. Is formed.

  Accordingly, the radially outer surface f1 of the first claw-shaped magnetic pole portion 22 having the first and second auxiliary grooves 25 and 26 has the bottom surfaces 25a and 26a of the first and second auxiliary grooves 25 and 26 having a planar shape. Therefore, as a whole, the cross-sectional shape in the direction perpendicular to the axis does not become a concentric shape with the central axis O of the rotation shaft 3 as the center.

  As shown in FIG. 12, the second rotor core 30 has the same shape as the first rotor core 20, and has four second claw-shaped magnetic pole portions 32 at equal intervals on the outer peripheral portion of the substantially disk-shaped second core base 31. Projecting radially outward and extending in the axial direction.

  The circumferential end surfaces 32a and 32b of the second claw-shaped magnetic pole portion 32 are flat surfaces extending in the radial direction. The angle in the circumferential direction of each second claw-shaped magnetic pole portion 32, that is, the angle between the circumferential end surfaces 32a and 32b is set smaller than the angle of the gap between the second claw-shaped magnetic pole portions 32 adjacent in the circumferential direction. Has been.

  Further, the radially outer surface f2 of the second claw-shaped magnetic pole portion 32 has a concentric circular arc surface whose cross-sectional shape in the axis orthogonal direction is centered on the central axis O of the rotating shaft 3, and the radially outer surface f2 The first auxiliary groove 35 and the second auxiliary groove 36 are provided.

  More specifically, as shown in FIG. 10, it is the radially outer surface f2 of the second claw-shaped magnetic pole portion 32, and the intermediate position in the circumferential direction of the second claw-shaped magnetic pole portion 32 from the central axis O of the rotating shaft 3. A straight line passing through is defined as a center line L2. The straight lines extending from the central axis at the angle θ2 in the clockwise direction and the counterclockwise direction with respect to the center line L2 are defined as a first straight line L2a and a second straight line L2b, respectively. Here, the angle θ2 was obtained using the following arithmetic expression based on the period φ of the cogging torque, as described above.

θ2 = (1/2 + n) · φ
Note that n is an integer, and in this embodiment, n = 0. The period φ of the cogging torque is 15 (= 360/24) degrees as described above.

Therefore, the angle θ2 is 7.5 (= 15/2) degrees, which is the same as the angle θ1.
Then, on the radially outer side surface f2, the first straight line L2a and the second straight line L2b, which are respectively displaced by 7.5 degrees in the clockwise direction and the counterclockwise direction around the center line L2, are fixed as intermediate positions in the circumferential direction. Grooves having a width of 1 mm are recessed in the axial direction.

  And the groove | channel which makes the 1st straight line L2a the circumferential direction intermediate position is the 1st auxiliary groove 35, and the groove | channel which makes the 2nd straight line L2b the circumferential direction intermediate position is the 2nd auxiliary groove 36 on the contrary. Therefore, the angle formed by the first auxiliary groove 35 and the second auxiliary groove 36 around the central axis O of the rotary shaft 3 coincides with the cogging torque period φ (= 15 degrees).

  That is, the angle formed by the center line L2 and the first straight line L2a and the angle formed by the center line L2 and the second straight line L2b are both a half period (= 7.5 degrees) of the period φ of the cogging torque. The second auxiliary groove 36 is formed at a symmetrical position with the center line L2 as the axis of symmetry.

  The first and second auxiliary grooves 35, 36 are formed in a U-shaped cross section in the direction perpendicular to the axis, and the bottom surfaces 35a, 36a are flat, and are perpendicular to the side surfaces extending from the outside in the radial direction from both sides. Is formed.

  Accordingly, the radially outer surface f2 of the second claw-shaped magnetic pole portion 32 having the first and second auxiliary grooves 35 and 36 is such that the bottom surfaces 35a and 36a of the first and second auxiliary grooves 35 and 36 are planar. Therefore, as a whole, the cross-sectional shape in the direction perpendicular to the axis does not become a concentric shape centering on the central axis O of the rotation shaft 3.

  As in the first embodiment, the second rotor core 30 is disposed between the first claw-shaped magnetic pole portions 22 to which the second claw-shaped magnetic pole portions 32 respectively correspond. At this time, in the second rotor core 30, the annular magnet 40 (see FIG. 11) is disposed (sandwiched) between the first core base 21 and the second core base 31 in the axial direction, as in the first embodiment. ) And assembled to the first rotor core 20 as described above.

Next, a method for manufacturing the first and second rotor cores 20 and 30 configured as described above will be described.
First, the first and second rotor cores 20 and 30 are formed by punching an electromagnetic steel plate made of a soft magnetic material, as shown in FIG. 13A, and through holes 20a and 30a, first and second core bases 21. , 31 and a portion extending in the radial direction from the first and second core bases 21, 31 are punched out. After punching and forming, the first auxiliary grooves 25 and 35 and the second auxiliary grooves are crushed (plastically deformed) with a press or the like on one side surface of the portion extending in the radial direction from the first and second core bases 21 and 31. 26, 36 are formed.

  And after forming the 1st auxiliary grooves 25 and 35 and the 2nd auxiliary grooves 26 and 36, the part extended in the diameter direction is bent and formed in the direction of an axis from the portion shown in Drawing 2 (a). Accordingly, the first and second rotor cores having the first and second claw-shaped magnetic pole portions 22 and 32 in which the first auxiliary grooves 25 and 35 and the second auxiliary grooves 26 and 36 are formed as shown in FIG. 20, 30 are formed.

Next, the operation of the embodiment configured as described above will be described below.
The rotor 4 forms a first auxiliary groove 25 and a second auxiliary groove 26 along the axial direction on the radially outer surface f1 of the first claw-shaped magnetic pole part 22 and is radially outside of the second claw-shaped magnetic pole part 32. A first auxiliary groove 35 and a second auxiliary groove 36 were formed in the side surface f2 along the axial direction. Therefore, the radial outer surface f1 of the first claw-shaped magnetic pole part 22 and the radial outer surface f2 of the second claw-shaped magnetic pole part 32 as a whole have an axial orthogonal cross-sectional shape centered on the central axis O of the rotating shaft 3. Does not become concentric.

  Therefore, as in the first embodiment, the first auxiliary grooves 25 and 35 and the second auxiliary grooves 26 and 36 are compared with those before the first auxiliary grooves 25 and 35 and the second auxiliary grooves 26 and 36 are formed. The above-described change in the magnetic field based on the formation becomes very large, and the holding force (detent torque) becomes large.

  In addition, the first auxiliary groove 25 and the second auxiliary groove 26 formed on the radially outer surface f1 of the first claw-shaped magnetic pole portion 22 are formed in line-symmetric positions with the center line L1 as an axis, and the first auxiliary groove 25 is formed. The angle formed by the (first straight line L1a) and the second auxiliary groove 26 (second straight line L1b) is formed to coincide with the period φ (= 15 degrees) of the cogging torque.

  Similarly, the first auxiliary groove 35 and the second auxiliary groove 36 formed on the radially outer surface f2 of the second claw-shaped magnetic pole portion 32 are formed in a line-symmetrical position about the center line L2, and the first auxiliary groove The angle formed by 35 (first straight line L2a) and the second auxiliary groove 36 (second straight line L2b) is formed to coincide with the period φ (= 15 degrees) of the cogging torque.

  That is, as shown in FIG. 14, the original pre-groove detent torque Ta before forming the first auxiliary grooves 25 and 35 and the second auxiliary grooves 26 and 36 and the auxiliary groove detent torque Tb are in phase. did. As a result, the pre-groove detent torque Ta is superimposed on the auxiliary groove detent torque Tb, so that the total detent torque Tc shown in FIG. 14 can be maximized.

Next, the effect of the said embodiment is described below.
(1) According to this embodiment, the radially outer surfaces f1, f2 of the first and second claw-shaped magnetic pole portions 22, 32 are first symmetrically positioned on both sides in the circumferential direction with the center lines L1, L2 as axes. Since the auxiliary grooves 25 and 35 and the second auxiliary grooves 26 and 36 are formed, the detent torque can be increased and the holding force of the brushless motor M in the stationary state can be increased.

  (2) According to the present embodiment, the first auxiliary grooves 25 and 35 and the second auxiliary grooves 26 and 36 are such that the angles θ1 and θ2 formed with the center lines L1 and L2 are the cogging torque period (angle φ), respectively. Since it is formed at a position having a half cycle (= φ / 2 = 7.5 degrees), the largest total detent torque Tc can be generated.

  In addition, since the first auxiliary grooves 25 and 35 and the second auxiliary grooves 26 and 36 are formed in line-symmetric positions, in the brushless motor M capable of rotating in the forward and reverse directions, cogging that occurs between forward rotation and reverse rotation is generated. There is no torque fluctuation.

  (3) According to the present embodiment, the first and second rotor cores 20 and 30 are punched from an electromagnetic steel plate made of a soft magnetic material, and the through holes 20a and 30a and the first and second core bases 21 and 31 are processed. And the site | part extended in the radial direction from the 1st and 2nd core bases 21 and 31 was stamped and formed. And the 1st and 2nd rotor cores 20 and 30 which have the 1st and 2nd nail | claw-shaped magnetic pole parts 22 and 32 were formed by bending and forming the site | part extended in radial direction in the axial direction.

  At this time, before the bending, the first auxiliary grooves 25 and 35 and the second auxiliary grooves 26 and 25 are crushed with a press or the like on one side surface of the portion extending in the radial direction from the first and second core bases 21 and 31. 36 was formed.

  Therefore, the first and second rotor cores 20 and 30 can be manufactured in three steps of punching, crushing, and bending, and the manufacturing cost of the first and second rotor cores 20 and 30 can be reduced.

The second embodiment may be modified as follows.
As shown in FIGS. 15A and 15B, in the rotor 4 shown in the second embodiment, the first claw-shaped magnetic pole portion 22 and the second rotor 4 shown in FIGS. 7A and 7B are similar to the rotor 4 shown in FIGS. The inter-pole auxiliary magnet 51 is interposed between the two claw-shaped magnetic pole portions 32, and the back auxiliary magnets 52 and 53 are interposed on the radially inner sides of the first and second claw-shaped magnetic pole portions 22 and 32, respectively. May be.

Accordingly, the detent torque can be further increased as in the case of the rotor 4 shown in FIG.
In the present embodiment, the first straight lines L1a, L2a and the second straight lines L1b, L2b that determine the circumferential intermediate positions of the first auxiliary grooves 25, 35 and the second auxiliary grooves 26, 36 are represented by the period of cogging torque (angle φ ). The position shifted from the first straight lines L1a, L2a and the second straight lines L1b, L2b may be implemented as an intermediate position between the first auxiliary grooves 25, 35 and the second auxiliary grooves 26, 36. In this case, although the detent torque becomes small, it can be used when adjusting the magnitude of the detent torque.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIGS.
In the present embodiment, the first auxiliary grooves 25 and 35 and the second auxiliary grooves 26 and 36 formed on the radially outer surfaces f1 and f2 of the first and second claw-shaped magnetic pole portions 22 and 32 shown in the second embodiment. Only the form is different. Therefore, the difference will be described.

  As shown in FIG. 16, on the radially outer surface f1 of each first claw-shaped magnetic pole portion 22 of the first rotor core 20, the first left auxiliary groove 25L and the first left auxiliary groove 25L are formed on both sides in the circumferential direction about the first straight line L1a. The first right auxiliary groove 25R is formed, and the second left auxiliary groove 26L and the second right auxiliary groove 26R are formed on both sides in the circumferential direction with the second straight line L1b as the axis of line symmetry.

Accordingly, four auxiliary grooves 25L, 25R, 26L, and 26R are formed on the radially outer surface f1.
More specifically, the first left auxiliary groove 25L and the first right auxiliary groove 25R of the first claw-shaped magnetic pole portion 22 are spaced apart from each other by the same offset angle Δθ that is set in advance on both sides in the circumferential direction with the first straight line L1a as the center line. Grooves having a certain width are recessed in the axial direction with a straight line extending from the axis O as the intermediate position in the circumferential direction.

  In FIG. 16, the groove on the clockwise side of the first straight line L1a is the first left auxiliary groove 25L, and on the contrary, the groove on the counterclockwise direction of the first straight line L1a is the first right auxiliary groove 25R.

Here, the deviation angle Δθ is set so that the following relational expression 1 is established.
(1/4 + n) · φ <Δθ <(3/4 + n) · φ
Since n = 0 at this time,
(15/4) degrees <Δθ <(45/4) degrees 3.75 degrees <Δθ <11.25 degrees. In this range, the straight line extending from the central axis O is set.

  Similarly, the second left auxiliary groove 26L and the second right auxiliary groove 26R of the first claw-shaped magnetic pole portion 22 are separated from the center axis O separated from each other by the deviation angle Δθ on both sides in the circumferential direction with the second straight line L1b as the center line. Grooves having a certain width are recessed in the axial direction with the extending straight line being an intermediate position in the circumferential direction.

  In FIG. 16, the groove on the clockwise side of the second straight line L1b is the second left auxiliary groove 26L, and on the contrary, the groove on the counterclockwise direction of the second straight line L1b is the second right auxiliary groove 26R.

  On the other hand, as shown in FIG. 16, on the radially outer side surface f2 of each second claw-shaped magnetic pole portion 32 of the second rotor core 30, the first left auxiliary groove 35L on both sides in the circumferential direction with the first straight line L2a as the axis of line symmetry. In addition, the first right auxiliary groove 35R and the second right auxiliary groove 36R are formed on both sides in the circumferential direction with the second straight line L2b as an axis of line symmetry.

Accordingly, four auxiliary grooves 35L, 35R, 36L, and 36R are formed on the radially outer surface f2.
The first left auxiliary groove 35L and the first right auxiliary groove 35R of the second claw-shaped magnetic pole portion 32 circulate around a straight line extending from the center axis O separated by the deviation angle Δθ on both sides in the circumferential direction with the first straight line L2a as the center line. Grooves having a certain width are recessed in the axial direction as intermediate positions in the direction.

  In FIG. 16, the groove on the clockwise direction side of the first straight line L2a is a first left auxiliary groove 35L, and on the contrary, the groove on the counterclockwise direction side of the first straight line L2a is a first right auxiliary groove 35R.

  Similarly, the second left auxiliary groove 36L and the second right auxiliary groove 36R of the second claw-shaped magnetic pole portion 32 are separated from the center axis O separated from each other by the deviation angle Δθ on both sides in the circumferential direction with the second straight line L2b as the center line. Grooves having a certain width are recessed in the axial direction with the extending straight line being an intermediate position in the circumferential direction.

  In FIG. 16, the groove on the clockwise side of the second straight line L2b is a second left auxiliary groove 36L, and on the contrary, the groove on the counterclockwise direction of the second straight line L2b is a second right auxiliary groove 36R.

In addition, it cannot be overemphasized that the 1st and 2nd rotor cores 20 and 30 of this embodiment can be manufactured with the manufacturing method demonstrated in 2nd Embodiment.
Next, the operation of the embodiment configured as described above will be described below.

  The rotor 4 is formed with first left and right auxiliary grooves 25L and 25R and second left and right auxiliary grooves 26L and 26R along the axial direction on the radially outer surface f1 of the first claw-shaped magnetic pole portion 22. Further, the first left and right auxiliary grooves 35L and 35R and the second left and right auxiliary grooves 36L and 36R are formed along the axial direction on the radially outer surface f2 of the second claw-shaped magnetic pole portion 32. Therefore, the radial outer surface f1 of the first claw-shaped magnetic pole part 22 and the radial outer surface f2 of the second claw-shaped magnetic pole part 32 as a whole have an axial orthogonal cross-sectional shape centered on the central axis O of the rotating shaft 3. Does not become concentric.

  Therefore, as in the second embodiment, the change in the magnetic field becomes much larger than before the first left auxiliary grooves 25L and 35L and the second right auxiliary grooves 26R and 36R are formed, and the holding force (detent torque) is increased. ) Will grow.

  Further, the first left and right auxiliary grooves 25L and 25R and the second left and right auxiliary grooves 26L and 26R formed on the radially outer surface f1 of the first claw-shaped magnetic pole portion 22 are symmetrical with respect to the center line L1. Formed. The first left and right auxiliary grooves 25L and 25R are formed in line-symmetric positions with the first straight line L1a as an axis, and the second left and right auxiliary grooves 26L and 26R are line-symmetric with respect to the second straight line L1b. Formed in position.

  Similarly, the first left and right auxiliary grooves 35L and 35R and the second left and right auxiliary grooves 36L and 36R formed on the radially outer surface f2 of the second claw-shaped magnetic pole portion 32 are symmetrical with respect to the center line L2. Formed in position. The first left and right auxiliary grooves 35L and 35R are formed in line-symmetric positions with the first straight line L2a as an axis, and the second left and right auxiliary grooves 36L and 36R are line-symmetric with respect to the second straight line L2b. Formed in position.

  Therefore, the period of the detent torque Tb by the four auxiliary grooves 25L, 25R, 26L, and 26R formed on the radially outer surface f1 and the four auxiliary grooves 35L, 35R, 36L, and 36R formed on the radially outer surface f2. Coincides with the period of the cogging torque.

As a result, a large total detent torque Tc can be extracted as in the second embodiment.
Incidentally, only the first left side auxiliary groove 25L and the second left side auxiliary groove 26L are formed on the radially outer surface f1 of the first claw-shaped magnetic pole portion 22, and the first left side is formed on the radially outer surface f2 of the second claw-shaped magnetic pole portion 32. When only the auxiliary groove 35L and the second left auxiliary groove 36L are formed, the detent torque Tb1 shown in FIG. 17 is obtained.

  That is, in this case, the detent torque Tb1 is obtained when the four auxiliary grooves 25L, 25R, 26L, and 26R are formed on the radially outer surface f1 and the four auxiliary grooves 35L, 35R, 36L, and 36R are formed on the radially outer surface f2. It becomes smaller than the detent torque Tb.

  On the other hand, only the first right auxiliary groove 25R and the second right auxiliary groove 26R are formed on the radially outer surface f1 of the first claw-shaped magnetic pole portion 22, and the first claw-shaped magnetic pole portion 32 is first formed on the radially outer surface f2. When only the right auxiliary groove 35R and the second right auxiliary groove 36R are formed, the detent torque Tb2 shown in FIG. 17 is obtained.

  In other words, the detent torque Tb2 in this case is obtained when the four auxiliary grooves 25L, 25R, 26L, and 26R are formed on the radial outer surface f1 and the four auxiliary grooves 35L, 35R, 36L, and 36R are formed on the radial outer surface f2. It becomes smaller than the detent torque Tb.

  For this reason, although the detent torque can be increased by the groove formation, it is small. Therefore, when adjusting the magnitude of the detent torque, it can be used to perform the adjustment by omitting one of the auxiliary grooves.

Thereby, according to this embodiment, there exists an effect similar to 2nd Embodiment.
(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described with reference to FIGS.

  In the present embodiment, the first auxiliary grooves 25 and 35 and the second auxiliary grooves 26 and 36 formed on the radially outer surfaces f1 and f2 of the first and second claw-shaped magnetic pole portions 22 and 32 shown in the second embodiment. The form is different. Therefore, the difference will be described.

As shown in FIGS. 18 to 21, the rotor 4 disposed inside the stator 2 includes first and second rotor cores 20 and 30 and an annular magnet 40 (see FIGS. 20 and 21).
(First rotor core 20)
As shown in FIG. 21, the first rotor core 20 has four first claw-shaped magnetic pole portions 22 projecting radially outward at equal intervals on the outer periphery of the first core base 21 formed in a substantially disc shape. At the same time, it extends in the axial direction.

  The angle in the circumferential direction of each first claw-shaped magnetic pole portion 22, that is, the angle between the circumferential end surfaces 22a and 22b is set smaller than the angle of the gap between the first claw-shaped magnetic pole portions 22 adjacent in the circumferential direction. Has been.

Further, the radially outer surface f <b> 1 of the first claw-shaped magnetic pole portion 22 has a concentric circular arc surface whose axial orthogonal cross-sectional shape is centered on the central axis O of the rotation shaft 3.
In the present embodiment, a pair of first auxiliary members are provided on the radially outer surface f <b> 1 in the same axial direction as the first auxiliary groove 25 formed in the second embodiment and at both axial ends of the first claw-shaped magnetic pole portion 22. Grooves 25x and 25y are formed. Similarly, a pair of second auxiliary grooves 26x are formed on the radially outer surface f1 in the same axial direction as the second auxiliary grooves 26 formed in the second embodiment and at both axial ends of the first claw-shaped magnetic pole portion 22. , 26y.

  That is, the pair of first auxiliary grooves 25x and 25y are formed so as not to communicate with each other in the axial direction, and the pair of second auxiliary grooves 26x and 26y are separated from each other without communicating in the axial direction. Is formed.

The groove surfaces of the first auxiliary grooves 25x and 25y and the second auxiliary grooves 26x and 26y are arc surfaces whose cross-sectional shape in the direction perpendicular to the axis is an arc.
Accordingly, the radially outer surface f1 of the first claw-shaped magnetic pole portion 22 having the first auxiliary grooves 25x and 25y and the second auxiliary grooves 26x and 26y has an axial orthogonal cross-sectional shape of the rotary shaft 3 in the central portion in the axial direction. Although it is concentric with the central axis O as the center, the entire radial outer surface f1 is not concentric.

(Second rotor core 30)
As shown in FIG. 21, the second rotor core 30 has the same shape as the first rotor core 20, and has four second claw-shaped magnetic pole portions 32 at regular intervals on the outer periphery of a substantially disc-shaped second core base 31. Projecting radially outward and extending in the axial direction.

  The circumferential end surfaces 32a and 32b of the second claw-shaped magnetic pole portion 32 are flat surfaces extending in the radial direction. The angle in the circumferential direction of each second claw-shaped magnetic pole portion 32, that is, the angle between the circumferential end surfaces 32a and 32b is set smaller than the angle of the gap between the second claw-shaped magnetic pole portions 32 adjacent in the circumferential direction. Has been.

Further, the radially outer surface f <b> 2 of the second claw-shaped magnetic pole part 32 has a concentric circular arc surface whose center is perpendicular to the central axis O of the rotation shaft 3.
In the present embodiment, a pair of first auxiliary members are provided on the radially outer surface f2 in the same axial direction as the first auxiliary groove 35 formed in the second embodiment and at both axial ends of the second claw-shaped magnetic pole portion 32. Grooves 35x and 35y are formed. Similarly, a pair of second auxiliary grooves 36x are formed on the radially outer surface f2 in the same axial direction as the second auxiliary grooves 36 formed in the second embodiment and at both axial ends of the second claw-shaped magnetic pole portion 32. , 36y are formed.

  That is, the pair of first auxiliary grooves 35x and 35y are formed so as not to communicate with each other in the axial direction, and the pair of second auxiliary grooves 36x and 36y are separated from each other without communicating in the axial direction. Is formed.

The groove surfaces of the first auxiliary grooves 35x and 35y and the second auxiliary grooves 36x and 36y are arc surfaces whose cross-sectional shapes in the direction perpendicular to the axis are arcs.
Therefore, the radially outer surface f2 of the second claw-shaped magnetic pole portion 32 having the first auxiliary grooves 35x and 35y and the second auxiliary grooves 36x and 36y has a cross-sectional shape perpendicular to the axis of the rotary shaft 3 at the central portion in the axial direction. Although it is concentric with the central axis O as the center, the entire radial outer surface f2 is not concentric.

  And like 2nd Embodiment, the 2nd rotor core 30 is arrange | positioned between each 1st nail | claw-shaped magnetic pole part 22 to which each 2nd nail | claw-shaped magnetic pole part 32 respectively respond | corresponds. At this time, in the second rotor core 30, the annular magnet 40 (see FIG. 20) is arranged (sandwiched) between the first core base 21 and the second core base 31 in the same manner as in the second embodiment. ) And assembled to the first rotor core 20 as described above.

In addition, it cannot be overemphasized that the 1st and 2nd rotor cores 20 and 30 of this embodiment can be manufactured with the manufacturing method demonstrated in 2nd Embodiment.
Next, the operation of the embodiment configured as described above will be described below.

  The rotor 4 forms a pair of first auxiliary grooves 25x and 25y at both axial ends of the first claw-shaped magnetic pole portion 22 on the radially outer surface f1 of the first claw-shaped magnetic pole portion 22, and also has a first claw-shaped configuration. A pair of second auxiliary grooves 26x and 26y were formed at both axial ends of the magnetic pole portion 22.

  In addition, the rotor 4 has a pair of first auxiliary grooves 35x and 35y formed at both ends in the axial direction of the second claw-shaped magnetic pole portion 32 on the radially outer surface f2 of the second claw-shaped magnetic pole portion 32, and the second A pair of second auxiliary grooves 36x and 36y were formed at both axial ends of the claw-shaped magnetic pole portion 32.

  Therefore, the radially outer surface f1 of the first claw-shaped magnetic pole portion 22 has a concentric circular shape in which the axial orthogonal cross-sectional shape is centered on the central axis O of the rotating shaft 3 in the central portion in the axial direction. The entire f1 is not concentric. Similarly, the radially outer surface f2 of the second claw-shaped magnetic pole portion 32 has a concentric circular shape in which the axial orthogonal cross-section is centered on the central axis O of the rotating shaft 3 in the central portion in the axial direction. The entire f2 is not concentric.

  Thus, as in the second embodiment, the pair of first auxiliary grooves 25x, 25y, 35x, 35y and the pair of second auxiliary grooves 26x, 26y, 36x, 36y are compared with before the pair of first auxiliary grooves 25x, 25y, 35x, 35y are formed. The change of the magnetic field based on the formation of the auxiliary grooves 25x, 25y, 35x, 35y and the pair of second auxiliary grooves 26x, 26y, 36x, 36y becomes very large, and the holding force (detent torque) becomes large.

  In addition, the pair of first auxiliary grooves 25x and 25y and the pair of second auxiliary grooves 26x and 26y formed on the radially outer surface f1 of the first claw-shaped magnetic pole portion 22 are formed in line-symmetrical positions about the center line L1. In addition, the angle formed by the pair of first auxiliary grooves 25x and 25y (first straight line L1a) and the pair of second auxiliary grooves 26x and 26y (second straight line L1b) is the period of cogging torque φ (= 15 degrees). Formed to match.

  Similarly, the pair of first auxiliary grooves 35x and 35y and the pair of second auxiliary grooves 36x and 36y formed on the radially outer surface f2 of the second claw-shaped magnetic pole portion 32 are placed in line-symmetrical positions about the center line L2. The angle formed by the pair of first auxiliary grooves 35x, 35y (first straight line L2a) and the pair of second auxiliary grooves 36x, 36y (second straight line L2b) is the cogging torque period φ (= 15 degrees). ) To match.

  Therefore, as in the second embodiment, the auxiliary groove detent torque (corresponding to the auxiliary groove detent torque Tb in FIG. 14) is superimposed on the detent torque before groove formation (corresponding to the detent torque Ta before groove formation in FIG. 14), The total detent torque (corresponding to the total detent torque Tc in FIG. 14) can be extracted to the maximum.

  Further, the axial lengths of the pair of first auxiliary grooves 25x and 25y and the pair of second auxiliary grooves 26x and 26y respectively formed at both ends in the axial direction of the first claw-shaped magnetic pole portion 22 can be appropriately changed. Similarly, the length in the axial direction of the pair of first auxiliary grooves 35x and 35y and the pair of second auxiliary grooves 36x and 36y formed at both ends in the axial direction of the second claw-shaped magnetic pole portion 32 can be appropriately changed. The magnitude of the detent torque can be adjusted by appropriately changing the lengths in the axial direction.

Next, the effect of the said embodiment is described below.
(1) According to the present embodiment, the radially outer surfaces f1, f2 of the first and second claw-shaped magnetic pole portions 22, 32 are paired at symmetrical positions on both sides in the circumferential direction with the center lines L1, L2 as axes. First auxiliary grooves 25x, 25y, 35x, 35y and a pair of second auxiliary grooves 26x, 26y, 36x, 36y were formed. Accordingly, the detent torque can be increased, and the holding force of the brushless motor M in the stationary state can be increased.

  (2) According to the present embodiment, the pair of first auxiliary grooves 25x, 25y, 35x, and 35y and the pair of second auxiliary grooves 26x, 26y, 36x, and 36y are angle θ1 formed with the center lines L1 and L2, respectively. , Θ2 is formed at a position where the cogging torque cycle (angle φ) is a half cycle (= φ / 2 = 7.5 degrees), so that a large total detent torque can be generated.

  In addition, since the pair of first auxiliary grooves 25x, 25y, 35x, 35y and the pair of second auxiliary grooves 26x, 26y, 36x, 36y are formed in line-symmetrical positions, in the brushless motor M that can rotate forward and backward, There is no period fluctuation of the cogging torque that occurs when rotating and when rotating.

  (3) According to the present embodiment, the pair of first auxiliary grooves 25x and 25y and the pair of second auxiliary grooves 26x and 26y are formed at both axial ends of the first claw-shaped magnetic pole part 22, respectively. Similarly, a pair of first auxiliary grooves 35x and 35y and a pair of second auxiliary grooves 36x and 36y are formed at both axial ends of the second claw-shaped magnetic pole portion 32, respectively.

  Accordingly, the axial lengths of the pair of first auxiliary grooves 25x, 25y, 35x, and 35y and the pair of second auxiliary grooves 26x, 26y, 36x, and 36y can be appropriately changed, and the lengths of the axial directions can be appropriately changed. By changing it, the magnitude of the detent torque can be adjusted.

  (4) According to the present embodiment, the first auxiliary grooves 25x, 25y, 35x, 35y and the pair of second auxiliary grooves 26x, 26y, 36x, 36y are the first and second claw-shaped magnetic pole portions 22, 32, respectively. It was formed in a limited range of both ends in the axial direction. Therefore, the dimensional change when forming the first auxiliary grooves 25x, 25y, 35x, 35y and the pair of second auxiliary grooves 26x, 26y, 36x, 36y by plastic deformation (crushing) can be reduced. .

The fourth embodiment may be modified as follows.
The pair of first auxiliary grooves 25x, 25y, 35x, 35y and the pair of second auxiliary grooves 26x, 26y, 36x, 36y of the fourth embodiment may be applied to the third embodiment. That is, a pair in the same axial direction as the four auxiliary grooves 25L, 25R, 26L, 26R on the radially outer surface f1 and the four auxiliary grooves 35L, 35R, 36L, 36R on the radially outer surface f2 formed in the third embodiment. The first auxiliary grooves 25x, 25y, 35x, 35y and the pair of second auxiliary grooves 26x, 26y, 36x, 36y may be formed respectively.

  As shown in FIG. 22, the depth of the pair of first auxiliary grooves 25x, 25y, 35x, 35y and the pair of second auxiliary grooves 26x, 26y, 36x, 36y is made deeper toward the axial end. It may be formed. The detent torque can be adjusted more finely.

  In the fourth embodiment, the pair of first auxiliary grooves 25x, 25y, 35x, and 35y and the pair of second auxiliary grooves 26x, 26y, 36x, and 36y have an arcuate cross-section in the axis orthogonal direction. It may be a shape.

  As shown in FIG. 23, on the radially outer side surface f1 of the first claw-shaped magnetic pole portion 22, the first auxiliary groove 25z is in the same axial direction as the pair of first auxiliary grooves 25x and 25y and at the central portion in the axial direction. And the second auxiliary groove 26z is formed in the same axial direction as the pair of second auxiliary grooves 26x and 26y and in the central portion in the axial direction.

  Similarly, on the radially outer surface f2 of the second claw-shaped magnetic pole portion 32, the first auxiliary groove 35z is formed in the same axial direction as the pair of first auxiliary grooves 35x and 35y and in the center portion in the axial direction, A second auxiliary groove 36z is formed in the same axial direction as the pair of second auxiliary grooves 36x and 36y and in the central portion in the axial direction.

  As a result, the radially outer surface f1 of the first claw-shaped magnetic pole portion 22 having the first auxiliary groove 25z and the second auxiliary groove 26z has a cross-sectional shape orthogonal to the central axis O of the rotary shaft 3 at both end portions in the axial direction. However, the entire outer radial surface f1 is not concentric.

  Similarly, the radially outer surface f2 of the second claw-shaped magnetic pole portion 32 having the first auxiliary groove 35z and the second auxiliary groove 36z has an axial orthogonal cross-sectional shape at the center axis O of the rotary shaft 3 at both end portions in the axial direction. However, the entire outer radial surface f2 is not concentric.

As a result, this case also has the same effect as the fourth embodiment.
Of course, the first auxiliary grooves 25z and 35z and the second auxiliary grooves 26z and 36z shown in FIG. 23 may be embodied as another example of the third embodiment.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described with reference to FIGS.
This embodiment is characterized by the radially outer surfaces f1, f2 of the first and second claw-shaped magnetic pole portions 22, 32 shown in the first embodiment. Therefore, the characteristic portion will be described in detail, and the detailed description of the portions common to the first embodiment will be omitted for convenience of description.

  As shown in FIG. 24, the brushless motor M of the present embodiment includes a stator 2, and a rotor 4 that is fixed to the rotating shaft 3 and rotates integrally with the rotating shaft 3 is disposed inside the stator 2. Yes.

  The stator 2 has a stator core 10, and twelve teeth 11 extend from the inside of the stator core 10. Each tooth 11 is a T-shaped tooth, and its radially inner circumferential surface 11 a is an arc surface in which a concentric arc centering on the central axis O of the rotating shaft 3 extends in the axial direction. In addition, a three-phase winding, that is, a U-phase winding 13u, a V-phase winding 13v, and a W-phase wire 13w are sequentially wound around the twelve teeth 11 by concentrated winding.

Then, a three-phase power supply voltage is applied to each of the wound phase windings 13u, 13v, and 13w to form a rotating magnetic field in the stator 2.
As shown in FIGS. 26 to 28, the rotor 4 disposed inside the stator 2 includes first and second rotor cores 20 and 30, an annular magnet 40, an interpole magnetic auxiliary magnet 51, and back auxiliary magnets 52 and 53. With.

(First rotor core 20)
As shown in FIG. 27, the first rotor core 20 has four first claw-shaped magnetic pole portions 22 projecting radially outward at equal intervals on the outer periphery of a first core base 21 formed in a substantially disc shape. At the same time, it extends in the axial direction. Here, in the first claw-shaped magnetic pole portion 22, a portion protruding radially outward from the outer peripheral surface 21 c of the first core base 21 is referred to as a first base portion 23, and a tip portion bent in the axial direction is the first magnetic pole portion. 24.

  Both circumferential end surfaces 22a and 22b of the first claw-shaped magnetic pole portion 22 including the first base portion 23 and the first magnetic pole portion 24 are flat surfaces extending in the radial direction. The angle in the circumferential direction of each first claw-shaped magnetic pole portion 22, that is, the angle between the circumferential end surfaces 22a and 22b is set smaller than the angle of the gap between the first claw-shaped magnetic pole portions 22 adjacent in the circumferential direction. Has been.

  Further, as shown in FIG. 27, the radially outer surface f <b> 1 of the first claw-shaped magnetic pole part 22 (first magnetic pole part 24) has a cross-sectional shape in the direction perpendicular to the axis centering on the central axis O of the rotating shaft 3. Not concentric.

  Specifically, as shown in FIG. 25, the interval (air gap) between the one end portion on the clockwise direction side of the radial outer surface f1 and the radial inner peripheral surface 11a of the tooth 11 is defined as a first air gap G1. On the other hand, an interval (air gap) between the other end portion on the counterclockwise direction side of the radially outer surface f1 and the radially inner peripheral surface 11a of the tooth 11 is defined as a second air gap G2. The radially outer surface f1 of the first magnetic pole portion 24 forms the first air gap G1 narrower than the second air gap G2, and the other end on the counterclockwise direction from one end on the clockwise direction side. The end portions are formed by arcuate surfaces.

  In other words, the radially outer surface f1 of the first magnetic pole portion 24 becomes longer as the distance (air gap) from the radially inner peripheral surface 11a of the tooth 11 becomes counterclockwise. Accordingly, the radially outer surface f <b> 1 is not an arc surface centered on the central axis O of the rotation shaft 3.

Then, when the first air gap G1 is α mm and the second air gap G2 is β mm, it is formed so that 1.0 <α / β ≦ 5.0.
(Second rotor core 30)
As shown in FIG. 27, the second rotor core 30 has four second claw-shaped magnetic poles at equal intervals on the outer periphery of a second core base 31 having the same shape as the first rotor core 20 and formed in a substantially disc shape. The portion 32 protrudes radially outward and extends in the axial direction. Here, in the second claw-shaped magnetic pole portion 32, the portion protruding radially outward from the outer peripheral surface 31c of the second core base 31 is referred to as a second base portion 33, and the tip portion bent in the axial direction is the second magnetic pole portion. 34.

  Both end surfaces 32a and 32b in the circumferential direction of the second claw-shaped magnetic pole portion 32 composed of the second base portion 33 and the second magnetic pole portion 34 are flat surfaces extending in the radial direction. The angle in the circumferential direction of each second claw-shaped magnetic pole portion 32, that is, the angle between the circumferential end surfaces 32a and 32b is set smaller than the angle of the gap between the second claw-shaped magnetic pole portions 32 adjacent in the circumferential direction. Has been.

  In addition, as shown in FIG. 27, the radially outer surface f <b> 2 of the second claw-shaped magnetic pole part 32 (second magnetic pole part 34) has an axial orthogonal cross-sectional shape centered on the central axis O of the rotating shaft 3. Not concentric.

  More specifically, as shown in FIG. 25, the distance (air gap) between the one end portion of the radially outer surface f2 in the clockwise direction and the radially inner peripheral surface 11a of the tooth 11 is the same as that of the first magnetic pole portion 24. First air gap G1. On the other hand, the distance (air gap) between the other end portion on the counterclockwise direction side of the radially outer surface f2 and the radially inner peripheral surface 11a of the tooth 11 is the same as that of the first magnetic pole portion 24, and the second air gap G2 To do. The radially outer surface f2 of the second magnetic pole portion 34 forms the first air gap G1 narrower than the second air gap G2, and the other end in the counterclockwise direction from one end on the clockwise direction side. The end portions are formed by arcuate surfaces.

  In other words, the radially outer surface f2 of the second magnetic pole portion 34 becomes longer as the distance (air gap) from the radially inner peripheral surface 11a of the tooth 11 moves toward the counterclockwise direction. Therefore, the radially outer surface f <b> 2 is not an arc surface centered on the central axis O of the rotation shaft 3.

Here, when the first air gap G1 is α mm and the second air gap G2 is β mm, the same as the first magnetic pole portion 24, 1.0 <α / β ≦ 5.0 is formed.
As in the first embodiment, the second rotor core 30 is disposed between the first claw-shaped magnetic pole portions 22 to which the second claw-shaped magnetic pole portions 32 respectively correspond. At this time, as shown in FIG. 26, in the second rotor core 30, the annular magnet 40 is disposed (sandwiched) between the first core base 21 and the second core base 31 in the same manner as in the first embodiment. ) And assembled to the first rotor core 20 as described above.

  In addition, as shown in FIGS. 28A and 28B, in the rotor 4, the interpole auxiliary magnet 51 is interposed between the first claw-shaped magnetic pole portion 22 and the second claw-shaped magnetic pole portion 32, and the first Further, back auxiliary magnets 52 and 53 are interposed on the radially inner sides of the second magnetic pole portions 24 and 34, respectively.

  Here, the magnetization direction of the inter-magnetic pole auxiliary magnet 51 is magnetized so that the first claw-shaped magnetic pole portion 22 side is an N pole and the second claw-shaped magnetic pole portion 32 side is an S pole. On the other hand, the back auxiliary magnet 52 shown in FIG. 28A is magnetized so that the first core base 21 side is an N pole and the second claw-shaped magnetic pole portion 32 side is an S pole. The back auxiliary magnet 53 shown in FIG. 28B is magnetized so that the second core base 31 side is an S pole and the first claw-shaped magnetic pole portion 22 side is an N pole.

Next, the operation of the embodiment configured as described above will be described below.
When the application of the three-phase power supply voltage to the phase windings 13u, 13v, 13w is stopped for the rotating brushless motor M, the rotating magnetic field disappears and the rotor 4 stops rotating. At this time, in the rotor 4, the magnetic flux that the first magnetic pole portion 24 of the first rotor core 20 flows into the teeth 11 of the stator core 10 and the magnetic flux that flows from the teeth 11 of the stator core 10 into the second magnetic pole portions 34 of the second rotor core 30 are the most. Stop at the pivot position where it becomes stable.

  That is, the radial outer surface f1 (radial outer surface f2) of one of the first and second magnetic pole portions 24 and 34 is located at a position facing the radial inner circumferential surface 11a of the tooth 11, respectively. is there. FIG. 24 shows a case where the radially outer surface f1 of the first claw-shaped magnetic pole portion 22 is located at a position facing the radially inner peripheral surface 11a of the tooth 11. In this case, since the brushless motor M is a motor with the rotor 4 having 8 poles and the stator 2 having 12 throttles, the radially outer surface f2 of the second magnetic pole portion 34 is located at an intermediate position between the teeth 11 and 11. .

  In this state, when the rotor 4 (rotating shaft 3) is rotated in the clockwise direction, the radially outer surface f1 of the first magnetic pole portion 24 is clockwise with respect to the radially inner peripheral surface 11a of the teeth 11 facing each other. Rotate around.

  At this time, the radially outer surfaces f1 and f2 of the first and second magnetic pole portions 24 and 34 are spaced from the radially inner peripheral surface 11a of the teeth 11 (air gap) at the other end on the counterclockwise direction side. It was formed with a circular arc surface that became longer as it went. Therefore, the magnetic flux gradually decreases with the clockwise rotation. Accordingly, since the action of returning to the original state of the large magnetic flux works, the holding force (detent torque) against the clockwise rotation is increased.

  On the other hand, when the rotor 4 (rotating shaft 3) is rotated counterclockwise, the radially outer surface f1 of the first magnetic pole portion 24 is opposite to the radially inner peripheral surface 11a of the teeth 11 facing each other. Rotate clockwise. At this time, the magnetic flux gradually increases with the rotation in the counterclockwise direction. Accordingly, since the magnetic flux is larger than the original large magnetic flux, the holding force (detent torque) against the counterclockwise rotation does not change.

  As described above, the radially outer surfaces f1 and f2 of the first and second magnetic pole portions 24 and 34 are spaced apart from the radially inner peripheral surface 11a of the teeth 11 (air gap) at the other end of the counterclockwise direction. It was formed with a circular arc surface that became longer toward the. As a result, in the rotational direction of the rotor 4, the detent torque for the clockwise rotation is larger than the holding force (detent torque) for the counterclockwise rotation.

  FIG. 29 shows an air gap with the radially inner peripheral surface 11a of the tooth 11 as the radially outer surfaces f1, f2 of the first and second magnetic pole portions 24, 34 are directed toward the other end on the counterclockwise direction side. It is a graph which shows the verification result of detent torque Tx1 when forming in the circular arc surface where becomes long. Here, the detent torque Tx1 obtained here is a detent torque obtained when (α / β) = 5.0 when the first air gap G1 is α mm and the second air gap G2 is β mm. is there.

  Further, the detent torque Tx2 with respect to the rotation angle shown in FIG. 29 is obtained when the radially outer surfaces f1 and f2 of the first and second magnetic pole portions 24 and 34 are concentric with the central axis O of the rotation shaft 3 as the center. Indicates detent torque. In other words, the detent torque Tx2 is a detent torque obtained when (α / β) = 1.0 when the first air gap G1 is α mm and the second air gap G2 is β mm.

  As is clear from FIG. 29, the detent torque Tx1 of the present embodiment has a large holding force (detent torque) in the clockwise direction with respect to the detent torque Tx2 in the case of a concentric circle centered on the central axis O of the rotating shaft 3. ). On the contrary, in the counterclockwise direction, it can be seen that the detent torque Tx1 of the present embodiment expresses a small holding force (detent torque) with respect to the detent torque Tx2.

  That is, when the first air gap G1 is α mm and the second air gap G2 is β mm, the first air gap G1 and the second air gap G2 are within a range of 1.0 <(α / β) ≦ 5.0. If set, the detent torque for the clockwise rotation can be increased with respect to the counterclockwise rotation without greatly reducing the output.

  Further, as apparent from the detent torque Tx1 in FIG. 29, the radially outer surfaces f1 and f2 of the first and second magnetic pole portions 24 and 34 are formed as arcuate surfaces, that is, smooth curves. It can be seen that the direction holding force (detent torque) changes smoothly with respect to the rotation angle.

Next, the effect of the said embodiment is described below.
(1) According to the present embodiment, the radially inner peripheral surface of the tooth 11 is directed toward the end portions on the counterclockwise direction on the radially outer surfaces f1, f2 of the first and second magnetic pole portions 24, 34. It was formed with a circular arc surface in which the distance (air gap) from 11a becomes longer. Accordingly, the holding force (detent torque) against rotation in the clockwise direction can be increased in the rotation direction of the rotor 4 than in the counterclockwise direction.

  In addition, since the radially outer surfaces f1 and f2 of the first and second magnetic pole portions 24 and 34 are formed in arcuate surfaces, that is, curved shapes, the holding force (detent torque) against rotation in the clockwise direction is set to the rotation angle. Can be changed smoothly.

  (2) According to this embodiment, when the first air gap G1 is α mm and the second air gap G2 is β mm, the first air gap is in the range of 1.0 <(α / β) ≦ 5.0. G1 and the second air gap G2 were set. Therefore, the detent torque for the clockwise rotation can be increased with respect to the counterclockwise rotation without greatly reducing the output.

  (3) According to the present embodiment, since the auxiliary magnets 51, 52, 53 are provided on the rotor 4, the magnetic flux generated between the first and second claw-shaped magnetic pole portions 22, 32 and the teeth 11 of the stator core 10. Since the change in the magnetic field can be further increased, the holding force (detent torque) can be further increased.

The fifth embodiment may be modified as follows.
In the present embodiment, the radially outer surfaces f1 and f2 of the first and second magnetic pole portions 24 and 34 are closer to the other end portion on the counterclockwise direction side with the radially inner peripheral surface 11a of the tooth 11. It was formed with a circular arc surface with a long air gap.

  On the contrary, this may be performed on an arc surface in which the air gap with the radially inner peripheral surface 11a of the tooth 11 becomes longer toward the one end portion on the radially outer side on the radially outer surfaces f1 and f2. Good.

In this case, in the rotation direction of the rotor 4, the holding force (detent torque) against rotation in the counterclockwise direction can be made larger than that in the clockwise direction.
In the present embodiment, the air gap with the radially inner peripheral surface 11a of the tooth 11 becomes longer as the cross-sectional shape of the radially outer surfaces f1 and f2 crosses in the direction perpendicular to the axis toward the other end on the counterclockwise direction. An arc surface, that is, a non-linear arc surface was used. This is the cross-sectional shape in the direction perpendicular to the axis of the radially outer surfaces f1 and f2 is a cross-sectional shape connecting both ends in the circumferential direction with a straight line (linear), and the more toward the other end on the counterclockwise direction side, You may form in the plane where an air gap with radial direction inner peripheral surface 11a becomes long.

  In the present embodiment, the inter-pole auxiliary magnet 51 is interposed between the first claw-shaped magnetic pole portion 22 and the second claw-shaped magnetic pole portion 32, and the radial directions of the first and second claw-shaped magnetic pole portions 22, 32 are provided. Although the back auxiliary magnets 52 and 53 are provided on the inner side, these may be omitted.

  In the present embodiment, the air with the radially inner peripheral surface 11a of the tooth 11 becomes closer to the radially outer side surfaces f1 and f2 of the first and second magnetic pole portions 24 and 34 toward the end on the counterclockwise direction side. It was formed with an arc surface with a long gap. This may be implemented by stepped surfaces on the radially outer surfaces f1 and f2.

  For example, as shown in FIG. 30, a linear outer surface f <b> 1 of the first magnetic pole portion 24 that passes from the central axis O of the rotating shaft 3 to the intermediate position in the circumferential direction of the first claw-shaped magnetic pole portion 22. The center line is L1. The radial outer surface f1 is a central axis O of the rotary shaft 3 in which the first arcuate surface f1x on the clockwise side and the second arcuate surface f1y on the counterclockwise direction are stepped from the center line L1. Are two concentric circles centered at.

  The air gap between the first arc surface f1x in the clockwise direction and the radially inner peripheral surface 11a of the teeth 11 is the same as the second arc surface f1y in the counterclockwise direction and the radially inner peripheral surface 11a of the teeth 11. It is formed to be smaller than the air gap.

  Similarly, it is defined as a straight center line L2 that is the radially outer surface f2 of the second magnetic pole portion 34 and passes through the intermediate position in the circumferential direction of the second claw-shaped magnetic pole portion 32 from the central axis O of the rotating shaft 3. The radially outer surface f2 is a central axis O of the rotary shaft 3 in which the first arcuate surface f2x on the clockwise direction side and the second arcuate surface f2y on the counterclockwise direction side are stepped from the center line L2. Are two concentric circles centered at.

  The air gap between the first arcuate surface f2x on the clockwise direction side and the radially inner peripheral surface 11a of the tooth 11 is the second arcuate surface f2y on the counterclockwise direction side and the radially inner peripheral surface 11a of the tooth 11. It is formed to be smaller than the air gap.

Even in such a configuration, it is possible to increase the holding force (detent torque) against rotation in the clockwise direction in the rotation direction of the rotor 4 rather than in the counterclockwise direction.
(Sixth embodiment)
Next, a sixth embodiment of the present invention will be described with reference to FIGS.

  In the second embodiment, the first auxiliary grooves 25 and 35 and the second auxiliary grooves 26 and 36 are formed on the radially outer surfaces f1 and f2 of the first and second claw-shaped magnetic pole portions 22 and 32, respectively. The present embodiment is characterized in that portions corresponding to the first auxiliary grooves 25 and 35 and the second auxiliary grooves 26 and 36 are formed by separate members.

Therefore, in the present embodiment, the characteristic portion of the rotor 4 will be described in detail, and a detailed description of portions common to the second embodiment will be omitted for convenience of description.
As shown in FIGS. 31 and 33, the rotor 4 disposed inside the stator 2 (see FIG. 8 of the second embodiment) includes the first and second rotor cores 20 and 30, the annular magnet 40, the first and the second The second back auxiliary magnets 55 and 56 and the first and second interpole auxiliary magnets 57 and 58 are provided. As shown in FIG. 31, the first and second rotor cores 20 and 30, the annular magnet 40, the first and second back auxiliary magnets 55 and 56, and the first and second interpole auxiliary magnets 57 and 58 are provided. The retaining force forming member 60 is mounted on the outer circumferential surface of the rotor 4 in the radial direction.

(First rotor core 20)
As shown in FIG. 35, a plurality of first rotor cores 20 are formed at equal intervals on the outer periphery of a first core base 21 formed in a substantially disc shape having a through hole 20a through which the rotary shaft 3 is inserted and fixed. In the embodiment, four first claw-shaped magnetic pole portions 22 protrude outward in the radial direction and extend in the axial direction. Here, in the first claw-shaped magnetic pole portion 22, a portion protruding radially outward from the outer peripheral surface 21 c of the first core base 21 is referred to as a first base portion 23, and a tip portion bent in the axial direction is the first magnetic pole portion. 24.

  Both circumferential end surfaces 22a and 22b of the first claw-shaped magnetic pole portion 22 including the first base portion 23 and the first magnetic pole portion 24 are flat surfaces extending in the radial direction. The angle in the circumferential direction of each first claw-shaped magnetic pole portion 22, that is, the angle between the circumferential end surfaces 22a and 22b is set smaller than the angle of the gap between the first claw-shaped magnetic pole portions 22 adjacent in the circumferential direction. Has been.

  Further, as shown in FIG. 35, the radially outer surface f <b> 1 of the first claw-shaped magnetic pole portion 22 has a concentric circular arc surface whose axial orthogonal cross-sectional shape is centered on the central axis O of the rotation shaft 3. . That is, the first and second auxiliary grooves 25 and 26 are not formed on the radially outer surface f1 of the present embodiment as in the second embodiment, and the center axis O of the rotation shaft 3 is the center. It is a concentric circular arc surface.

(Second rotor core 30)
As shown in FIG. 35, the second rotor core 30 has the same shape as the first rotor core 20, and is formed on the outer peripheral portion of the substantially disk-shaped second core base 31 having a through hole 30 a that penetrates and fixes the rotating shaft 3. At the same interval, four second claw-shaped magnetic pole portions 32 protrude radially outward and extend in the axial direction. Here, in the second claw-shaped magnetic pole portion 32, the portion protruding radially outward from the outer peripheral surface 31c of the second core base 31 is referred to as a second base portion 33, and the tip portion bent in the axial direction is the second magnetic pole portion. 34.

  The circumferential end surfaces 32a and 32b of the second claw-shaped magnetic pole portion 32 including the second base portion 33 and the second magnetic pole portion 34 are flat surfaces extending in the radial direction. The angle in the circumferential direction of each second claw-shaped magnetic pole portion 32, that is, the angle between the circumferential end surfaces 32a and 32b is set smaller than the angle of the gap between the second claw-shaped magnetic pole portions 32 adjacent in the circumferential direction. Has been.

  Further, the radially outer surface f <b> 2 of the second claw-shaped magnetic pole part 32 has a concentric circular arc surface whose center is perpendicular to the central axis O of the rotation shaft 3. That is, the first and second auxiliary grooves 35 and 36 are not formed on the radially outer surface f2 of the present embodiment as in the second embodiment, and the center axis O of the rotation shaft 3 is the center. It is a concentric circular arc surface.

  And like 2nd Embodiment, the 2nd rotor core 30 is arrange | positioned between each 1st nail | claw-shaped magnetic pole part 22 to which each 2nd nail | claw-shaped magnetic pole part 32 respectively respond | corresponds. At this time, in the second rotor core 30, the annular magnet 40 (see FIG. 33) is disposed (clamped) between the first core base 21 and the second core base 31 in the same manner as in the second embodiment. In this manner, the first rotor core 20 is assembled.

(Annular magnet 40)
As shown in FIGS. 33 and 35, the annular magnet 40 sandwiched between the first rotor core 20 and the second rotor core 30 is a disk-like permanent magnet made of a neodymium magnet.

  As shown in FIG. 35, the annular magnet 40 has a through hole 41 penetrating the rotating shaft 3 at the center position thereof. Then, one side surface 40 a of the annular magnet 40 abuts the opposing surface 21 a of the first core base 21 and the other side surface 40 b of the annular magnet 40 contacts the opposing surface 31 a of the second core base 31, respectively. Is sandwiched and fixed between the first rotor core 20 and the second rotor core 30.

The outer diameter of the annular magnet 40 is set to coincide with the outer diameters of the first and second core bases 21 and 31, and the thickness is set to a predetermined thickness.
That is, as shown in FIG. 33, when the annular magnet 40 is disposed between the first rotor core 20 and the second rotor core 30, the tip surface 22 c of the first magnetic pole portion 24 and the opposite surface of the second core base 31. 31b becomes flush. Similarly, the front end surface 32c of the second magnetic pole portion 34 and the opposite surface 21b of the first core base 21 are flush with each other. Further, the outer peripheral surface 40 c of the annular magnet 40 is flush with the outer peripheral surfaces 21 c and 31 c of the first and second core bases 21 and 31.

  As shown in FIG. 33, the annular magnet 40 is magnetized in the axial direction, and the first rotor core 20 side is an N pole (first magnetic pole), and the second rotor core 30 side is an S pole (second magnetic pole). It is magnetized to become. Accordingly, the first claw-shaped magnetic pole portion 22 of the first rotor core 20 functions as an N pole (first magnetic pole) by the annular magnet 40, and the second claw-shaped magnetic pole portion 32 of the second rotor core 30 functions as an S pole (first magnetic pole). 2 magnetic poles).

  Therefore, the rotor 4 of the present embodiment is a so-called Landel type rotor using the annular magnet 40. In the rotor 4, the first claw-shaped magnetic pole portions 22 that are N poles and the second claw-shaped magnetic pole portions 32 that are S poles are alternately arranged in the circumferential direction, and the number of magnetic poles is eight.

(First and second back auxiliary magnets 55 and 56)
As shown in FIG. 33, it is the back surface 24 a (radially inner surface) of the first magnetic pole portion 24, the outer peripheral surface 31 c of the second core base 31, the outer peripheral surface 40 c of the annular magnet 40, and the first base portion 23. The first back auxiliary magnet 55 is disposed in a space formed by the surface 23a on the two rotor core 30 side.

  The first back auxiliary magnet 55 has a substantially rectangular parallelepiped shape in which the cross section in the direction perpendicular to the axis has a fan shape, and the side that contacts the back surface 24a of the first magnetic pole portion 24 is the first claw so as to reduce the leakage magnetic flux at that portion. The N pole having the same polarity as the magnetic pole portion 22 is magnetized in the radial direction so that the side in contact with the second core base 31 becomes the S pole having the same polarity as the second core base 31.

  As shown in FIG. 33, it is the back surface 34 a (radially inner surface) of the second magnetic pole portion 34, the outer peripheral surface 21 c of the first core base 21, the outer peripheral surface 40 c of the annular magnet 40, and the second base 33 A second back auxiliary magnet 56 is disposed in a space formed by the surface 33a on the one rotor core 20 side.

  The second back auxiliary magnet 56 has a substantially rectangular parallelepiped shape in which the cross section in the direction perpendicular to the axis has a fan shape, and the side of the second magnetic pole portion 34 that contacts the back surface 34a is the second claw so as to reduce the leakage magnetic flux at that portion. The S pole having the same polarity as the magnetic pole portion 32 is magnetized in the radial direction so that the side in contact with the first core base 21 becomes the N pole having the same polarity as the first core base 21.

(First and second inter-pole auxiliary magnets 57, 58)
As shown in FIG. 34, between the first claw-shaped magnetic pole portion 22 where the first back auxiliary magnet 55 is arranged and the second claw-shaped magnetic pole portion 32 where the second back auxiliary magnet 56 is arranged, between the circumferential directions. The first and second interpole auxiliary magnets 57 and 58 are respectively disposed.

  Specifically, the first interpole auxiliary magnet 57 includes a flat surface formed by one circumferential end surface 22a of the first claw-shaped magnetic pole portion 22 and a circumferential end surface of the first back auxiliary magnet 55, and a second surface. The claw-shaped magnetic pole portion 32 is disposed between the other circumferential end surface 32 b and a flat surface formed by the circumferential end surface of the second back auxiliary magnet 56.

  Similarly, the second interpole auxiliary magnet 58 includes a flat surface formed by the other circumferential end surface 22b of the first claw-shaped magnetic pole portion 22 and the circumferential end surface of the first back auxiliary magnet 55, and a second claw. The magnetic pole portion 32 is disposed between one circumferential end surface 32 a and a flat surface formed by the circumferential end surface of the second back auxiliary magnet 56.

  The first and second interpole auxiliary magnets 57 and 58 have the same magnetic poles as the first and second claw-shaped magnetic pole portions 22 and 32, respectively (the first claw-shaped magnetic pole portion 22 side is N-pole, The magnets are magnetized in the circumferential direction so that the two-claw-shaped magnetic pole portion 32 side becomes the S pole.

(Holding force forming member 60)
A holding force forming member 60 is mounted on the radially outer surface of the rotor 4 assembled as described above.

  As shown in FIGS. 31 to 34, the holding force forming member 60 is formed of an electromagnetic steel plate made of a soft magnetic material in the present embodiment. Further, the holding force forming member 60 may be formed of a composite magnetic material. The holding force forming member 60 is formed in a cylindrical shape, and its inner surface in the radial direction has first and second rotor cores 20 and 30, an annular magnet 40, first and second back auxiliary magnets 55 and 56, first and first. It is crimped | bonded with the radial direction outer surface of the rotor 4 which assembled | attached the auxiliary magnets 57 and 58 between 2 poles. The holding force forming member 60 is integrally fixed to the rotor 4 and is not displaced with respect to the rotor 4. The cylindrical holding force forming member 60 has an axial length that matches the axial length of the rotor 4.

  The radially outer surface f <b> 3 of the holding force forming member 60 is a concentric circular arc surface in which the cross-sectional shape in the axis orthogonal direction is centered on the central axis O of the rotation shaft 3. And each area | region surface which is the radial direction outer surface f3 and opposes the radial direction outer surface f1 of the 1st magnetic pole part 24 is the 1st large diameter outer surface f3a with a large outer diameter. Two grooves, a first groove 61 and a second groove 62, are recessed in each first large-diameter outer surface f3a.

  More specifically, as shown in FIG. 32, on each first large-diameter outer surface f3a, a straight line passing through the center position O of the rotating shaft 3 and the intermediate position in the circumferential direction of the first claw-shaped magnetic pole portion 22 is the center line. Let L1. Straight lines extending from the central axis O located at an angle θ1 in the clockwise direction and the counterclockwise direction with respect to the center line L1 are defined as a first straight line L1a and a second straight line L1b, respectively.

Here, the angle θ1 was obtained using the following arithmetic expression based on the period of cogging torque (angle φ).
θ1 = (1/2 + n) · φ
Note that n is an integer, and in this embodiment, n = 0.

The period φ of the cogging torque is generally a value obtained by dividing 360 degrees by the least common multiple of the number of magnetic poles of the rotor 4 and the number of slots of the stator 2.
In the present embodiment, since the number of magnetic poles of the rotor 4 is 8 and the number of slots of the stator 2 is 12, the least common multiple is 24. The period φ of the cogging torque is 15 (= 360/24) degrees.

Accordingly, the angle θ1 is 7.5 (= 15/2) degrees.
Then, on each first large-diameter outer surface f3a, a first straight line L1a and a second straight line L1b that are displaced by 7.5 degrees in the clockwise direction and the counterclockwise direction about the center line L1 are specified. And the groove | channel with a fixed width | variety is each recessedly provided in an axial direction by making the 1st straight line L1a and the 2nd straight line L1b into the intermediate position of the circumferential direction.

  And the groove | channel which makes the 1st straight line L1a the circumferential direction intermediate position is the 1st groove | channel 61, and the groove | channel which makes the 2nd straight line L1b the circumferential direction intermediate position the 2nd groove | channel 62 on the contrary. Therefore, the angle formed by the first groove 61 and the second groove 62 around the central axis O of the rotating shaft 3 coincides with the cogging torque period φ (= 15 degrees).

  That is, the angle formed by the center line L1 and the first straight line L1a and the angle formed by the center line L1 and the second straight line L1b are both a half period (= 7.5 degrees) of the period φ of the cogging torque. The second groove 62 is formed at a symmetrical position with the center line L1 as the axis of symmetry.

  Further, since each first large-diameter outer surface f3a is provided with the first and second grooves 61 and 62, the cross-sectional shape in the direction perpendicular to the axis as a whole is a concentric arc centered on the central axis O of the rotating shaft 3. It does not become a shape.

  On the other hand, each region surface which is the radially outer surface f3 of the holding force forming member 60 and faces the radially outer surface f2 of the second magnetic pole portion 34 has the same outer diameter as that of the first large-diameter outer surface f3a. A large second large-diameter outer surface f3b is formed. Two grooves, a first groove 63 and a second groove 64, are formed in the second large-diameter outer surface f3b.

  More specifically, as shown in FIG. 32, in each second large-diameter outer surface f3b, a straight line passing through the intermediate position in the circumferential direction of the second claw-shaped magnetic pole portion 32 from the central axis O of the rotating shaft 3 is the center line. Let L2. Straight lines extending from the central axis O located at the angle θ2 in the clockwise direction and the counterclockwise direction with respect to the center line L2 are defined as a first straight line L2a and a second straight line L2b, respectively.

Here, the angle θ2 was obtained using the following arithmetic expression based on the period of cogging torque (angle φ).
θ2 = (1/2 + n) · φ
Note that n is an integer, and in this embodiment, n = 0.

The period φ of the cogging torque is generally a value obtained by dividing 360 degrees by the least common multiple of the number of magnetic poles of the rotor 4 and the number of slots of the stator 2.
In the present embodiment, since the number of magnetic poles of the rotor 4 is 8 and the number of slots of the stator 2 is 12, the least common multiple is 24. The period φ of the cogging torque is 15 (= 360/24) degrees.

Therefore, the angle θ2 is 7.5 (= 15/2) degrees.
Then, on each second large-diameter outer surface f3b, a first straight line L2a and a second straight line L2b that are respectively displaced by 7.5 degrees in the clockwise direction and the counterclockwise direction about the center line L2 are specified. And the groove | channel with a fixed width | variety is each recessedly provided in an axial direction by making the 1st straight line L2a and the 2nd straight line L2b into the intermediate position of the circumferential direction.

  And the groove | channel which makes the 1st straight line L2a the circumferential direction intermediate position the 1st groove | channel 63, and the groove | channel which makes the 2nd straight line L2b the circumferential direction intermediate position the 2nd groove | channel 64 on the contrary. Therefore, the angle formed by the first groove 63 and the second groove 64 about the central axis O of the rotary shaft 3 coincides with the cogging torque period φ (= 15 degrees).

  That is, the angle formed by the center line L2 and the first straight line L2a and the angle formed by the center line L2 and the second straight line L2b are both a half period (= 7.5 degrees) of the period φ of the cogging torque. The second groove 64 is formed at a symmetrical position with the center line L1 as the axis of symmetry.

  In addition, since each second large-diameter outer surface f3b is provided with the first and second grooves 63, 64, the cross-sectional shape of the axis orthogonal direction as a whole is a concentric arc centered on the central axis O of the rotating shaft 3. It does not become a shape.

  A portion of the radially outer surface f3 of the holding force forming member 60 between the alternately formed first and second large-diameter outer surfaces f3a and f3b is irradiated with a laser. To increase the magnetic resistance. This prevents leakage of magnetic flux from the first large-diameter outer surface f3a portion of the holding force forming member 60 to the second large-diameter outer surface f3b portion.

Next, the operation of the embodiment configured as described above will be described below.
First and second large-diameter outer surfaces f3a and f3b are formed on the radially outer surface f3 of the holding force forming member 60 mounted on the outer peripheral surface of the rotor 4, and the first and second large-diameter outer surfaces f3a, First grooves 61 and 63 and second grooves 62 and 64 were formed in f3b. Therefore, the radial outer surface f <b> 3 of the holding force forming member 60 does not have a concentric circular shape in which the cross-sectional shape in the axis orthogonal direction is centered on the central axis O of the rotation shaft 3 as a whole.

  Therefore, as in the second embodiment, the change in the magnetic field based on the first grooves 61 and 63 and the second grooves 62 and 64 formed on the first and second large-diameter outer surfaces f3a and f3b is very large. Accordingly, the holding force (detent torque) is increased.

  In addition, the first groove 61 and the second groove 62 formed on the first large-diameter outer surface f3a are formed in line-symmetric positions with the center line L1 as an axis, and the first groove 61 (first straight line L1a) and the second groove The angle formed by the groove 62 (second straight line L1b) was formed to coincide with the period φ (= 15 degrees) of the cogging torque.

  Similarly, the first groove 63 and the second groove 64 formed on the second large-diameter outer surface f3b are formed at line symmetrical positions with the center line L2 as an axis, and the first groove 63 (first straight line L2a) and the second groove 63 are formed. The angle formed by the groove 64 (second straight line L2b) was formed so as to coincide with the period φ (= 15 degrees) of the cogging torque.

Therefore, the total detent torque Tc shown in the second embodiment can be maximized.
Next, the effect of the said embodiment is described below.

  (1) According to this embodiment, the holding force forming member 60 is mounted on the radially outer surface of the rotor 4. The first and second large-diameter outer surfaces f3a and f3b are formed on the radially outer surface f3 of the holding force forming member 60, and the center line L1 is formed on the first and second large-diameter outer surfaces f3a and f3b. The first grooves 61 and 63 and the second grooves 62 and 64 are formed at symmetrical positions on both sides in the circumferential direction about L2. As a result, the detent torque can be increased and the holding force of the brushless motor M in a stationary state can be increased.

  (2) According to the present embodiment, the first grooves 61 and 63 and the second grooves 62 and 64 are configured so that the angles θ1 and θ2 formed with the center lines L1 and L2 are half periods of the cogging torque period (angle φ). Since it is formed at a position where (= φ / 2 = 7.5 degrees), the largest total detent torque Tc can be generated.

  In addition, since the first grooves 61 and 63 and the second grooves 62 and 64 are formed in line-symmetrical positions, in the brushless motor M that can rotate forward and backward, the cogging torque generated in the forward rotation and the reverse rotation is generated. There is no period fluctuation.

  (3) According to this embodiment, by attaching the holding force forming member 60 to the radially outer surface of the rotor 4, the holding force forming member 60 allows the first and second interpole auxiliary magnets 57 and 58. The radially outer surface is covered. Accordingly, since the holding force forming member 60 presses the radially outer side surfaces of the first and second interpole auxiliary magnets 57 and 58 that the rotor 4 rotates, the centrifugal force due to the rotation is generated between the first and second poles. Even if it is added to the auxiliary magnets 57, 58, there is no possibility of jumping out of the first and second rotor cores 20, 30.

  (4) According to the present embodiment, the detent torque can be increased by simply assembling the existing rotor 4 with the holding force forming member 60, and the holding force of the brushless motor M in the stationary state can be increased. Can be increased.

  In addition, when the magnitude of the detent torque is desired to be adjusted, the sizes of the first grooves 61 and 63 and the second grooves 62 and 64 formed in the first and second large-diameter outer surfaces f3a and f3b may be adjusted. . That is, various detent torques can be set only by changing the design of only the holding force forming member 60.

Note that the sixth embodiment may be modified as follows.
In the present embodiment, the first and second large-diameter outer surfaces f3a and f3b are formed on the radially outer surface f3, and the first grooves 61 and 63 and the first grooves 61 and 63 are formed on the first and second large-diameter outer surfaces f3a and f3b. Two grooves 62 and 64 were formed. Instead of the first grooves 61, 63 and the second grooves 62, 64, the first grooves 61, 63 and the second grooves 62, 64 are formed on the first and second large-diameter outer surfaces f3a, f3b. You may implement by forming the protrusion (projection) extended in an axial direction in a position. As a result, the same effect as in the above embodiment can be obtained.

  In the present embodiment, the first and second large-diameter outer surfaces f3a and f3b may be changed to the shapes shown in the first to fifth embodiments. Thereby, the same effects as those of the first to fourth embodiments can be obtained.

  In the present embodiment, the holding force forming member 60 has a cylindrical shape. As shown in FIGS. 36 and 37, this may be formed by a bottomed cylindrical body 65 in which one opening of the holding force forming member 60 is closed. That is, a through hole 66 a through which the rotation shaft 3 passes is formed in the bottom wall 66 of the bottomed cylindrical body 65. Then, the rotor 4 is accommodated on the inner surface of the bottomed cylindrical body 65. At this time, the radially inner side surface of the rotor 4 is crimped to the radially inner side surface of the bottomed cylindrical body 65. As a result, the bottomed cylindrical body 65 is integrally fixed to the rotor 4.

  And the radial direction outer side surface f3 of the bottomed cylindrical body 65 is a 1st and 2nd large diameter outer side surface in each area | region surface which respectively opposes the radial direction outer side surfaces f1 and f2 of the 1st and 2nd magnetic pole parts 24 and 34. f3a and f3b are formed, and first grooves 61 and 63 and second grooves 62 and 64 are formed on the first and second large-diameter outer surfaces f3a and f3b, respectively.

As a result, the detent torque can be increased, and the holding force of the brushless motor M in a stationary state can be increased.
Further, the other opening of the bottomed cylindrical body 65 that accommodates the rotor 4 is closed by a cover plate 67 in which a through hole 67a is formed at the center. The cover plate 67 is bonded and fixed to the rotor 4 with an adhesive.

  Accordingly, since the radially outer surfaces of the first and second interpole auxiliary magnets 57 and 58 are pressed by the radially inner surface of the bottomed cylindrical body 65, the centrifugal force due to rotation is the first and second. There is no possibility of jumping out of the first and second rotor cores 20 and 30 even when added to the inter-pole auxiliary magnets 57 and 58.

  In addition, since both side surfaces of the rotor 4 are covered with the cover plate 67 and the bottom wall 66 of the bottomed cylindrical body 65, the first and second interpole auxiliary magnets 57 and 58, and the first The 1st and 2nd back auxiliary magnets 55 and 56 are lost, and the fragments do not protrude from the axial direction.

(Seventh embodiment)
Next, a seventh embodiment of the present invention will be described with reference to FIGS.
In the present embodiment, the configuration corresponding to the holding force forming member 60 of the sixth embodiment is different and has a feature.

Therefore, in the present embodiment, the holding force forming member 60 having a different configuration will be described in detail, and the detailed description of the portions common to the fifth embodiment will be omitted for the sake of description.
As shown in FIGS. 38 and 39, a holding force forming member 60 is attached to the rotor 4.

  The holding force forming member 60 includes a first plate 71 disposed on the first rotor core 20 side and a second plate 72 disposed on the second rotor core 30 side. In the present embodiment, the first and second plates 71 and 72 are both formed of an electromagnetic steel plate made of a soft magnetic material. Moreover, you may form the 1st and 2nd plates 71 and 72 with a composite magnetic material.

(First plate 71)
The 1st plate 71 is formed in disk shape, and the through-hole 71a which penetrates the rotating shaft 3 is formed in the center part. The outer diameter of the first plate 71 is formed to be the same as the outer diameter of the radially outer surfaces f1, f2 of the first and second magnetic pole portions 24, 34.

  The first plate 71 has a pair of first and second holding force forming bars 73 and 74 in a radial direction at a position corresponding to the outer peripheral edge of the first plate 71 and the radial outer surface f1 of each first magnetic pole portion 24. Each is formed to extend toward the second plate 72 disposed on the second rotor core 30 side along the outer surface f1.

  Caulking claws 73a and 74a are provided at the front ends of the first and second holding force forming bars 73 and 74, respectively. As shown in FIG. 38, the first plate 71 is connected to the second plate 72 by the crimping claws 73 a, 74 a being engaged with the outer peripheral edge of the second plate 72. Is done.

(Second plate 72)
The 2nd plate 72 is formed in disk shape, and the through-hole 72a which penetrates the rotating shaft 3 is formed in the center part. The outer diameter of the second plate 72 is formed to be the same as the outer diameter of the radially outer surfaces f1, f2 of the first and second magnetic pole portions 24, 34.

  In addition, the second plate 72 has a pair of first and second holding force forming bars 75 and 76 in a radial direction at a position corresponding to the outer peripheral edge of the second plate 72 and the radial outer surface f <b> 2 of each second magnetic pole portion 34. The outer side surface f2 is formed to extend toward the first plate 71 disposed on the first rotor core 20 side.

  Caulking claws 75a and 76a are provided at the distal ends of the first and second holding force forming bars 75 and 76, respectively. As shown in FIG. 38, the second plate 72 is connected to the first plate 71 by the crimping claws 75 a and 76 a being engaged with the outer peripheral edge of the first plate 71. Is done.

That is, the first plate 71 and the second plate 72 sandwich the rotor 4 and rotate integrally with the rotor 4.
Next, the arrangement positions of the first and second holding force forming bars 73 and 74 provided on the first plate 71 arranged on the radially outer surface f1 of the first magnetic pole portion 24 will be described.

  As shown in FIG. 40, on each radially outer surface f1, a straight line passing from the central axis O of the rotating shaft 3 to the intermediate position in the circumferential direction of the first claw-shaped magnetic pole portion 22 is defined as a center line L1. Straight lines extending from the central axis located at the angle θ1 in the clockwise direction and the counterclockwise direction with respect to the center line L1 are defined as a first straight line L1a and a second straight line L1b, respectively.

Here, the angle θ1 was obtained using the following arithmetic expression based on the period of cogging torque (angle φ).
θ1 = (1/2 + n) · φ
Note that n is an integer, and in this embodiment, n = 0.

The period φ of the cogging torque is generally a value obtained by dividing 360 degrees by the least common multiple of the number of magnetic poles of the rotor 4 and the number of slots of the stator 2.
In the present embodiment, since the number of magnetic poles of the rotor 4 is 8 and the number of slots of the stator 2 is 12, the least common multiple is 24. The period φ of the cogging torque is 15 (= 360/24) degrees.

Accordingly, the angle θ1 is 7.5 (= 15/2) degrees.
Here, on each radially outer surface f1, a first straight line L1a and a second straight line L1b that are respectively displaced by 7.5 degrees in the clockwise direction and the counterclockwise direction around the center line L1 are specified. And the 1st and 2nd holding force formation bar provided in the 1st plate 71 so that it may be located in the axial direction orthogonal to the 1st straight line L1a and the 2nd straight line L1b on the radial direction outer surface f1. 73 and 74 are arranged. Therefore, the angle formed by the first holding force forming bar 73 and the second holding force forming bar 74 around the central axis O of the rotating shaft 3 coincides with the cogging torque period φ (= 15 degrees).

  That is, the angle formed by the center line L1 and the first straight line L1a and the angle formed by the center line L1 and the second straight line L1b are both a half period (= 7.5 degrees) of the period φ of the cogging torque, and the first holding force is formed. The bar 73 and the second holding force forming bar 74 are formed at symmetrical positions with a straight line in the axial direction orthogonal to the center line L1 as a symmetry axis.

Next, the arrangement positions of the first and second holding force forming bars 75 and 76 provided on the second plate 72 arranged on the radially outer surface f2 of the second magnetic pole portion 34 will be described.
As shown in FIG. 40, on each radially outer surface f2, a straight line that passes from the central axis O of the rotating shaft 3 through the intermediate position in the circumferential direction of the second claw-shaped magnetic pole portion 32 is defined as a center line L2. The straight lines extending from the central axis located at the angle θ2 in the clockwise direction and the counterclockwise direction with respect to the center line L2 are defined as a first straight line L2a and a second straight line L2b, respectively.

Here, the angle θ2 was obtained using the following arithmetic expression based on the period of cogging torque (angle φ).
θ2 = (1/2 + n) · φ
Note that n is an integer, and in this embodiment, n = 0.

The period φ of the cogging torque is generally a value obtained by dividing 360 degrees by the least common multiple of the number of magnetic poles of the rotor 4 and the number of slots of the stator 2.
In the present embodiment, since the number of magnetic poles of the rotor 4 is 8 and the number of slots of the stator 2 is 12, the least common multiple is 24. The period φ of the cogging torque is 15 (= 360/24) degrees.

Therefore, the angle θ2 is 7.5 (= 15/2) degrees.
Here, on each radially outer surface f2, a first straight line L2a and a second straight line L2b that are respectively displaced by 7.5 degrees in the clockwise direction and the counterclockwise direction about the center line L2 are specified. The first and second holding force forming bars provided on the second plate 72 so as to be positioned on the radially outer surface f2 and in the axial direction perpendicular to the first straight line L2a and the second straight line L2b. 75 and 76 are arranged. Therefore, the angle formed by the first holding force forming bar 75 and the second holding force forming bar 76 around the central axis O of the rotating shaft 3 coincides with the cogging torque period φ (= 15 degrees).

  That is, the angle formed by the center line L2 and the first straight line L2a and the angle formed by the center line L2 and the second straight line L2b are both a half period (= 7.5 degrees) of the period φ of the cogging torque, and the first holding force is formed. The bar 75 and the second holding force forming bar 76 are formed at symmetrical positions with a straight line in the axial direction orthogonal to the center line L2 as a symmetry axis.

Next, the operation of the embodiment configured as described above will be described below.
The first plate 71 and the second plate 72 are connected to each other via the first holding force forming bars 73 and 75 and the second holding force forming bars 74 and 76 with the rotor 4 interposed therebetween. The first and second holding force forming bars 73 and 74 of the first plate 71 are disposed on the radially outer surface f1 of each first magnetic pole portion 24, and the first and second holding of the second plate 72 are performed. The force forming bars 75 and 76 are disposed on the radially outer side surface f2 of each second magnetic pole portion 34.

  For this reason, each of the radially outer surfaces f1 and f2 is apparently formed by the first holding force forming bars 73 and 75 and the second holding force forming bars 74 and 76 so that the cross-sectional shape in the axis orthogonal direction is the center axis O of the rotating shaft 3. It does not have a concentric circle shape.

  From this, the change in the magnetic field based on the first holding force forming bars 73 and 75 and the second holding force forming bars 74 and 76 arranged on the radially outer surfaces f1 and f2 becomes very large, and the holding force is increased. (Detent torque) increases.

  In addition, the first and second holding force forming bars 73 and 74 of the first plate 71 are formed in a line symmetrical position with the center line L1 as an axis, and the first holding force forming bar 73 and the second holding force forming bar. The angle formed by 74 coincides with the cogging torque period φ (= 15 degrees).

  Similarly, the first and second holding force forming bars 75 and 76 of the second plate 72 are formed in a line symmetrical position with the center line L2 as an axis, and the first holding force forming bar 75 and the second holding force forming are formed. The angle formed by the bar 76 was formed to coincide with the cogging torque period φ (= 15 degrees).

Therefore, the total detent torque Tc can be extracted to the maximum as in the second embodiment.
Next, the effect of the said embodiment is described below.
(1) According to the present embodiment, the first and second holding force forming bars 73 and 74 of the first plate 71 are disposed on the radially outer side surface f1 of each first magnetic pole portion 24 and the second plate 72. The first and second holding force forming bars 75 and 76 are arranged on the radially outer surface f2 of each second magnetic pole portion 34.

  Then, the first and second holding force forming bars 73 and 74 arranged on the radially outer side surface f1 of each first magnetic pole part 24 are made to have the same polarity (N pole) as the first magnetic pole part 24, and each second magnetic pole part. The first and second holding force forming bars 75 and 76 arranged on the radially outer side surface f <b> 2 of the portion 34 have the same polarity (S pole) as the second magnetic pole portion 34. Accordingly, the first and second holding force forming bars 73 and 74 and the first and second holding force forming bars 75 and 76 on the radially outer surface f2 are disposed on the radially outer surface f1 so as to be separated from each other. Therefore, since the short-circuit magnetic flux can be reduced, the detent torque can be increased and the output can be maintained.

  Moreover, the first and second holding force forming bars 73 and 74 of the first plate 71 are arranged at symmetrical positions on both sides in the circumferential direction with the center line L1 as an axis, and the first and second holding forces of the second plate 72 are arranged. The forming bars 75 and 76 are arranged at symmetrical positions on both sides in the circumferential direction with the center line L2 as an axis.

As a result, the detent torque can be increased and the holding force of the brushless motor M in a stationary state can be increased.
(2) According to the present embodiment, the first holding force forming bars 73 and 75 and the second holding force forming bars 74 and 76 have angles θ1 and θ2 formed with the center lines L1 and L2, respectively, so that the cogging torque period ( Since it is formed at a position where the half cycle (= φ / 2 = 7.5 degrees) of angle φ), the largest total detent torque Tc can be generated.

  In addition, since the first holding force forming bars 73 and 75 and the second holding force forming bars 74 and 76 are formed in line-symmetric positions, in the brushless motor M that can rotate forward and backward, the case of normal rotation and the case of reverse rotation There is no period fluctuation of the cogging torque generated in.

  (3) According to the present embodiment, the first and second plates 71 and 72 cover the both outer surfaces in the axial direction of the rotor 4, so the first and second interpole auxiliary magnets 57 and 58, The 1st and 2nd back auxiliary magnets 55 and 56 are lost, and the fragments do not protrude from the axial direction.

  (4) According to the present embodiment, the detent torque can be increased by simply assembling the first plate 71 and the second plate 72 to the existing rotor 4, and the brushless motor M can be kept stationary. The holding force can be increased.

  In addition, when it is desired to adjust the magnitude of the detent torque with respect to the existing rotor 4, the first holding force forming bars 73 and 75 and the second holding force forming bar 74 formed on the first and second plates 71 and 72. , 76 may be adjusted. That is, various detent torques can be set only by changing the design of only the first and second plates 71 and 72.

  (5) According to this embodiment, since the first plate 71 and the second plate 72 are formed of the same shape and the same material, the first plate 71 and the second plate 72 can be easily assembled. The number of parts can be reduced.

Note that the seventh embodiment may be modified as follows.
In the present embodiment, the first and second holding force forming bars 73 and 74 of the first plate 71 and the first and second holding force forming bars 75 and 76 of the second plate 72 are provided, respectively. As shown in FIGS. 41 and 42, for example, the first plate 71 omits the first and second holding force forming bars 73 and 74. The second plate 72 may be provided with the first and second holding force forming bars 73 and 74 of the first plate 71 omitted.

  In the present embodiment, the two holding force forming bars, the first holding force forming bars 73 and 75 and the second holding force forming bars 74 and 76, are arranged on each radially outer side surface f1 and f2. However, the present invention is not limited to this, and one or three or more may be arranged.

The above embodiments may be modified as follows.
In the second to fourth embodiments, when the first auxiliary grooves 25 and 35 and the second auxiliary grooves 26 and 36 of the first and second rotor cores 20 and 30 are formed, they are plastically deformed (crushed). Formed. This may be performed by changing the material of the portion where the groove is formed. Here, changing the material means, for example, irradiating a portion where a groove is formed, such as a composite magnetic material, with a laser so that only the connecting portion of the composite magnetic material is demagnetized to increase the magnetic resistance. An effect equivalent to that of the auxiliary groove is achieved.

  Of course, the portion where the first grooves 61 and 63 and the second grooves 62 and 64 formed on the first and second large-diameter outer surfaces f3a and f3b of the holding force forming member 60 of the sixth embodiment are formed. The material may be changed so as to be changed. Similarly, the material of the first and second holding force forming bars 73 and 74 of the seventh embodiment may be changed from other parts.

  In the above embodiments, the brushless motor M has 8 poles and 12 slots. This may be applied to a 2-pole / 3-throttle brushless motor such as a 10-pole 15-slot brushless motor.

  DESCRIPTION OF SYMBOLS 1 ... Motor housing, 2 ... Stator, 3 ... Rotating shaft, 4 ... Rotor, 10 ... Stator core, 11 ... Teeth, 11a ... Inner peripheral surface, 12 ... Slot, 13u ... U-phase winding, 13v ... V-phase winding, 13w ... W phase winding, 20 ... first rotor core, 20a ... through hole, 21 ... first core base, 21a ... opposite surface, 21b ... opposite surface, 22 ... first claw-shaped magnetic pole portion, 22a, 22b ... end surface , 22c ... tip surface, 23 ... first base, 23a ... surface, 24 ... first magnetic pole, 24a ... back surface, 25, 26 ... first and second auxiliary grooves, 25a, 26a ... bottom surface, 25x, 25y, 25z ... 1st auxiliary groove, 26x, 26y, 26z ... 2nd auxiliary groove, 25L, 26L ... 1st and 2nd left side auxiliary groove, 25R, 26R ... 1st and 2nd right side auxiliary groove, 30 ... 2nd rotor core, 30a ... through hole, 31 ... second core base, 31 ... opposing face, 31b ... anti-facing face, 32 ... second claw-shaped magnetic pole parts, 32a and 32b ... end face, 32c ... tip face, 33 ... second base part, 33a ... face, 34 ... second magnetic pole part, 34a ... back face 35a, 36 ... first and second auxiliary grooves, 35a, 36a ... bottom surface, 35x, 35y, 35z ... first auxiliary grooves, 36x, 36y, 36z ... second auxiliary grooves, 35L, 36L ... first and second. Left side auxiliary groove, 35R, 36R ... first and second right side auxiliary groove, 40 ... annular magnet, 40a, 40b ... side face, 40c ... outer peripheral surface, 41 ... through hole, 51 ... auxiliary magnet between magnetic poles, 52, 53 ... back side Auxiliary magnets 55, 56 ... first and second backside auxiliary magnets, 57, 58 ... first and second interpole auxiliary magnets, 60 ... holding force forming member, 61, 62 ... first and second grooves, 63, 64: first and second grooves, 65: bottomed cylindrical body, 66: bottom wall, 66a: penetrating , 67 ... Cover plate, 67a ... Through hole, 71, 72 ... First and second plates, 71a, 72a ... Through hole, 73, 74 ... First and second holding force forming bars, 73a, 74a ... Caulking claws 75, 76 ... first and second holding force forming bars, 75a, 76a ... caulking claws, M ... brushless motor, O ... central axis, f1, f2, f3 ... radially outer surface, f1a, f2a ... first Plane, f1b, f2b ... second plane, f3a, f3b ... first and second large diameter surfaces (region surfaces), f1x, f1y ... first and second arc surfaces, f2x, f2y ... first and second arc surfaces L1, L2 ... center line, L1a, L2a ... first straight line, L1b, L2b ... second straight line, P1, P2 ... vertex, La, Lb ... ridge line, θa, θb ... tilt angle, θ1, θ2, φ ... angle , Δθ: Deviation angle, Ta: Detent torque before groove formation Tb ... auxiliary groove detent torque, Tc ... total detent torque, G1, G2 ... first and second air gaps.

Claims (24)

A first core base fixed to the rotating shaft, and provided with a plurality of first claw-shaped magnetic pole portions provided at equal intervals on the outer peripheral portion of the first core base and extending in the axial direction from the outer peripheral portion; 1 rotor core,
A second core base fixed to the rotating shaft, and provided with a plurality of second claw-shaped magnetic pole portions provided at equal intervals on an outer peripheral portion of the second core base and extending in the axial direction from the outer peripheral portion; A second rotor core in which each of the second claw-shaped magnetic pole portions is disposed between the circumferentially adjacent first claw-shaped magnetic pole portions;
Magnetized along the axial direction and disposed between the first core base of the first rotor core and the second core base of the second rotor core, and the first claw-shaped magnetic pole portions function as first magnetic poles. A rotor including a field magnet that causes each of the second claw-shaped magnetic pole portions to function as a second magnetic pole,
The rotor according to claim 1, wherein a cross-sectional shape of the first claw-shaped magnetic pole part and the second claw-shaped magnetic pole part in a direction perpendicular to the axis of the radially outer surface is not a concentric circle centering on a central axis of the rotating shaft. The rotor according to claim 1, wherein
A first auxiliary magnet is disposed between the first claw-shaped magnetic pole portion and the second claw-shaped magnetic pole portion adjacent to each other in the circumferential direction, and the radial direction of the first claw-shaped magnetic pole portion and the second claw-shaped magnetic pole portion. A rotor characterized in that second auxiliary magnets are arranged on the inside. The rotor according to claim 1 or 2,
The cross-sectional shape of the first claw-shaped magnetic pole portion and the second claw-shaped magnetic pole portion in the axially orthogonal direction of the radially outer surface is a convex shape that protrudes radially outward toward the center position. . The rotor according to claim 3, wherein
The radially outer surfaces of the first claw-shaped magnetic pole part and the second claw-shaped magnetic pole part are formed from a plurality of planes formed along the axial direction. The rotor according to claim 1 or 2,
An auxiliary groove extending along the axial direction is formed at a position half the period of the cogging torque on both sides in the circumferential direction from the circumferential center position of the radially outer side surface of the first claw-shaped magnetic pole portion and the second claw-shaped magnetic pole portion. Rotor characterized by The rotor according to claim 5, wherein
The auxiliary groove extending along the axial direction is formed on both sides of the first claw-shaped magnetic pole part and the second claw-shaped magnetic pole part. The rotor according to claim 5, wherein
The auxiliary groove extending along the axial direction is formed in a central portion of the first claw-shaped magnetic pole part and the second claw-shaped magnetic pole part. The rotor according to claim 1 or 2,
Auxiliary extending along the axial direction from the center position in the circumferential direction of the radially outer side surface of the first claw-shaped magnetic pole part and the second claw-shaped magnetic pole part to positions offset from the half of the period of the cogging torque on both sides in the circumferential direction. A rotor formed with a groove. The rotor according to claim 8, wherein
The auxiliary groove extending along the axial direction is formed on both sides of the first claw-shaped magnetic pole part and the second claw-shaped magnetic pole part. The rotor according to claim 8, wherein
The auxiliary groove extending along the axial direction is formed in a central portion of the first claw-shaped magnetic pole part and the second claw-shaped magnetic pole part. The rotor according to any one of claims 8 to 10,
The positions deviated from the half position of the cogging torque period are symmetrical positions on both sides in the circumferential direction from the half position of the cogging torque period, and auxiliary grooves are respectively formed at the symmetrical positions. Rotor to do. The rotor according to claim 1 or 2,
The cross-sectional shape of the first claw-shaped magnetic pole part and the second claw-shaped magnetic pole part in the axially orthogonal direction of the radially outer side surface is such that the outer diameter continuously decreases from one end to the other end in the circumferential direction. A rotor characterized by being formed into the following. The rotor according to claim 12,
The cross-sectional shape in the direction perpendicular to the axis of the radially outer surface is such that when the air gap at one end in the circumferential direction is α and the air gap at the other end in the circumferential direction is β,
1.0 <α / β ≦ 5.0
Rotor characterized by that. The rotor according to claim 12 or 13,
The rotor is characterized in that a cross-sectional shape of the radially outer surface in a direction perpendicular to the axis is a curved shape. The rotor according to claim 1 or 2,
The cross-sectional shape of the first claw-shaped magnetic pole part and the second claw-shaped magnetic pole part in the direction perpendicular to the axis of the radial outer surface is such that the outer diameter gradually decreases from one end to the other end in the circumferential direction. A rotor characterized by being formed into the following. The rotor according to claim 15, wherein
The cross-sectional shape in the direction perpendicular to the axis of the radially outer surface is formed with two arc surfaces at the center position, and the outer diameter of the arc surface on the other end side in the circumferential direction is on the one end side in the circumferential direction. A rotor characterized by being formed shorter than the outer diameter of the arc surface. A first core base fixed to the rotating shaft, and provided with a plurality of first claw-shaped magnetic pole portions provided at equal intervals on the outer peripheral portion of the first core base and extending in the axial direction from the outer peripheral portion; 1 rotor core,
A second core base fixed to the rotating shaft, and provided with a plurality of second claw-shaped magnetic pole portions provided at equal intervals on an outer peripheral portion of the second core base and extending in the axial direction from the outer peripheral portion; A second rotor core in which each of the second claw-shaped magnetic pole portions is disposed between the circumferentially adjacent first claw-shaped magnetic pole portions;
Magnetized along the axial direction and disposed between the first core base of the first rotor core and the second core base of the second rotor core, and the first claw-shaped magnetic pole portions function as first magnetic poles. A rotor including a field magnet that causes each of the second claw-shaped magnetic pole portions to function as a second magnetic pole,
A holding force forming member is fitted on a radially outer surface of the first claw-shaped magnetic pole portion and the second claw-shaped magnetic pole portion alternately arranged in the circumferential direction, and the holding force forming member has a radially outer surface of the holding force forming member. The cross-sectional shape in the direction perpendicular to the axis of the area surface facing the radially outer surface of the first claw-shaped magnetic pole part and the second claw-shaped magnetic pole part is formed so as not to be concentric with the central axis of the rotation axis as the center. Rotor characterized by The rotor according to claim 17, wherein
A first auxiliary magnet is disposed between the first claw-shaped magnetic pole portion and the second claw-shaped magnetic pole portion adjacent to each other in the circumferential direction, and the radial direction of the first claw-shaped magnetic pole portion and the second claw-shaped magnetic pole portion. A rotor characterized in that second auxiliary magnets are arranged on the inside. The rotor according to claim 17 or 18,
Each region surface that is on the radially outer surface of the holding force forming member and faces the radially outer surfaces of the first claw-shaped magnetic pole portion and the second claw-shaped magnetic pole portion is surrounded by a circumferential center position of the region surface. A rotor characterized in that auxiliary grooves or ridges extending along the axial direction are formed at half the period of the cogging torque on both sides in the direction. A first core base fixed to the rotating shaft, and provided with a plurality of first claw-shaped magnetic pole portions provided at equal intervals on the outer peripheral portion of the first core base and extending in the axial direction from the outer peripheral portion; 1 rotor core,
A second core base fixed to the rotating shaft, and provided with a plurality of second claw-shaped magnetic pole portions provided at equal intervals on an outer peripheral portion of the second core base and extending in the axial direction from the outer peripheral portion; A second rotor core in which each of the second claw-shaped magnetic pole portions is disposed between the circumferentially adjacent first claw-shaped magnetic pole portions;
Magnetized along the axial direction and disposed between the first core base of the first rotor core and the second core base of the second rotor core, and the first claw-shaped magnetic pole portions function as first magnetic poles. A rotor including a field magnet that causes each of the second claw-shaped magnetic pole portions to function as a second magnetic pole,
A first plate is disposed on the axially outer surface of the first core base, and is disposed on a second plate on the axially outer surface of the second core base, so that the first plate and the second plate are radially outside. A rotor characterized in that the peripheral portions are connected by a holding force forming bar that covers a part of the radially outer surface of the first and second claw-shaped magnetic pole portions along the axial direction. The rotor of claim 20,
The holding force forming bar extends along the axial direction from the circumferential center position of the radially outer surface of the first claw-shaped magnetic pole portion and the second claw-shaped magnetic pole portion to a position half the period of the cogging torque on both sides in the circumferential direction. The rotor is a pair of the holding force forming bars.   A motor comprising the rotor according to any one of claims 1 to 21. The motor according to claim 22,
The motor is a two-pole / three-slot brushless motor. It is a manufacturing method of the rotor according to any one of claims 5 to 11,
After punching and forming a through hole, a disk-shaped core base, and a portion extending in the radial direction from the core base by punching the magnetic steel sheet, the portion extending in the radial direction from the core base An auxiliary groove is formed by plastic deformation of one side surface of the first and second rotor cores, and the first and second rotor cores are formed by bending the radially extending portion in the axial direction after forming the auxiliary groove. A method for manufacturing a rotor.