JP2016077113A - Landel rotor and motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a Lundell type rotor capable of simplifying the shape of a rectification magnet for suppressing a leakage magnetic flux between a claw-like magnetic pole and a field magnet and a leakage magnetic flux between claw-like magnetic poles which are neighboring to each other in a circumferential direction.SOLUTION: The Lundell type rotor includes an annular rectification magnet 42 which is disposed so as to pass between a field magnet 40 and first and second claw-like magnetic poles 22 and 32 (first and second magnetic pole parts 24 and 34) in a radial direction. In the rectification magnet 42, each of both axial end faces 42a and 42b is one flat surface, and an inner peripheral surface 42c and an outer peripheral surface 42d are formed circular in an axial view. The rectification magnet 42 is magnetized so as to generate a magnetic flux in the radial direction on abutment surfaces X1 and X2 which are abutted with back faces of the first and second claw-like magnetic poles 22 and 32, and magnetized mainly in a circumferential component in an inter-pole part 42m corresponding to a gap between the first and second claw-like magnetic poles 22 and 32 in the circumferential direction.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a Landell rotor and a motor.

  The rotor of the motor includes two rotor cores that are combined with a plurality of claw-shaped magnetic poles on the outer periphery of the core base, and a field magnet that is arranged between the axial directions and magnetized in the axial direction. There is a so-called permanent magnet field Landell type rotor in which each claw-shaped magnetic pole functions alternately as a different magnetic pole.

  In such a Landell type rotor, for example, in Patent Document 1, a back magnet part arranged between a claw-shaped magnetic pole and a field magnet and magnetized in a radial direction to suppress leakage magnetic flux therebetween is adjacent to the circumferential direction. An inter-pole magnet portion is arranged between the matching claw-shaped magnetic poles and magnetized in the circumferential direction to suppress leakage magnetic flux therebetween, and these are integrally formed. According to this configuration, an increase in the number of parts can be suppressed as much as possible by integrally forming them while improving the output by the back magnet part and the interpole magnet part that suppress the leakage magnetic flux.

JP 2013-118801 A

  By the way, in a rotor as described above, a magnet (hereinafter referred to as a rectifying magnet) in which a back magnet part and an inter-pole magnet part are integrated has a complicated shape in which irregularities are repeated in the axial direction and the radially outer side. It is realistic to perform injection molding at However, when injection molding a bonded magnet, it is common to use a thermoplastic resin as a binder, and since the resin ratio is high, compared to magnets and sintered magnets formed by compression molding, etc. It is disadvantageous in terms of improving magnetic properties. In addition, the rigidity of the binder is reduced due to the fact that the binder is made of a thermoplastic resin or welds caused by injection molding. Therefore, it is necessary to take measures such as increasing the physique in order to ensure strength, resulting in increased manufacturing costs. There was a problem to do. For this reason, simplification of the shape of a rectification magnet is desired so that magnets other than the bond magnet formed by injection molding can be selected.

  The present invention has been made to solve the above-mentioned problems, and its purpose is to reduce the leakage flux between the claw-shaped magnetic pole and the field magnet and the leakage flux between the claw-shaped magnetic poles adjacent in the circumferential direction. An object of the present invention is to provide a Landel rotor and a motor that can simplify the shape of a rectifying magnet to be suppressed.

  The Landell type rotor that solves the above-mentioned problems has a plurality of claw-shaped magnetic poles in the circumferential direction, and the first and second rotor cores assembled in such a manner that the claw-shaped magnetic poles are alternately arranged in the circumferential direction; And being arranged between the axial directions of the second rotor core and being magnetized in the axial direction, the claw-shaped magnetic pole of the first rotor core functions as the first magnetic pole, and the claw-shaped magnetic pole of the second rotor core is A field magnet that functions as a second magnetic pole, and an annular rectifier magnet that is disposed so as to pass between the radial direction of the field magnet and each of the claw-shaped magnetic poles. Both end surfaces are one flat surface, the inner peripheral surface and the outer peripheral surface are circular in an axial view, and magnetic flux is generated along the radial direction at the contact surface that contacts the back surface of each claw-shaped magnetic pole. Parts that are magnetized and correspond between the claw-shaped magnetic poles The circumferential component is mainly magnetized.

  According to this configuration, the annular rectifier magnet has a simple shape in which both end surfaces in the axial direction are one flat surface, and the inner peripheral surface and the outer peripheral surface are circular in the axial direction view. For example, a compression-molded magnet, a sintered magnet, or the like other than the bonded magnet can be used as the rectifying magnet. The rectifying magnet is magnetized so that a magnetic flux is generated along the radial direction at the contact surface that contacts the back surface of each claw-shaped magnetic pole, and a circumferential component is mainly applied at a portion corresponding to each claw-shaped magnetic pole. Magnetized. For this reason, it is possible to suppress the leakage magnetic flux between the claw-shaped magnetic pole and the field magnet and the leakage magnetic flux between the claw-shaped magnetic poles adjacent in the circumferential direction by the magnetic action of the rectifying magnet.

  Further, since the outer peripheral surface of the rectifier magnet is circular when viewed in the axial direction and does not have a portion (conventional interpole magnet portion) that enters between the circumferential directions of the claw-shaped magnetic poles, the clearance in the circumferential direction with the claw-shaped magnetic poles High dimensional accuracy is not required.

A motor that solves the above-described problems includes the Landel rotor and a stator that generates a rotating magnetic field.
According to this configuration, the above-described effect can be obtained in the motor.

  According to the Landell type rotor and motor of the present invention, the shape of the rectifying magnet for suppressing the leakage flux between the claw-shaped magnetic pole and the field magnet and the leakage flux between the claw-shaped magnetic poles adjacent in the circumferential direction is simplified. can do.

It is sectional drawing of the brushless motor of embodiment. It is a disassembled perspective view of the brushless motor of the same form. It is a perspective view of the rotor of the same form, a support plate, and a sensor magnet. It is a disassembled perspective view of the rotor of the same form.

Hereinafter, an embodiment of a Landel rotor and a motor will be described.
As shown in FIG. 1, the brushless motor M of the present embodiment is a Landel motor, and is used for a position control device arranged in a vehicle engine room, more specifically, a valve timing variable device connected to the engine. It is.

  The brushless motor M has a motor case 1. The motor case 1 has a cylindrical front housing 2 made of a magnetic material formed in a covered cylindrical shape, and an end frame 3 made of aluminum (nonmagnetic material) that closes the opening of the cylindrical front housing 2. ing.

  In the brushless motor M, a stator 5 is fixed to the inner peripheral surface of the cylindrical front housing 2, and a rotor 7 having a so-called Landel type structure that is fixed to the rotating shaft 6 and rotates integrally with the rotating shaft 6 inside the stator 5. Is arranged. The rotating shaft 6 is a non-magnetic stainless steel shaft that is housed and fixed in a bearing 8 that is housed and fixed in a bearing holder 2 a formed in the cylindrical front housing 2 and a bearing holder 3 a that is formed in the end frame 3. The bearing 9 supports the motor case 1 so as to be rotatable. The bearing 9 is made of a nonmagnetic material.

  An axially inner side surface 3 b (end surface on the rotor 7 side) of the end frame 3 has a planar shape orthogonal to the axis of the rotary shaft 6. The bearing holding portion 3a protrudes from the axial inner side surface 3b to the axial inner side (the rotor 7 side), and the bearing 9 fixed to the bearing holding portion 3a is closer to the rotor 7 than the axial inner side surface 3b. It is arranged to protrude.

  The tip of the rotating shaft 6 protrudes from the cylindrical front housing 2. The valve timing (the relative rotational phase of the camshaft with respect to the crankshaft of the engine) is appropriately changed by the rotational driving of the rotating shaft 6.

[Stator 5]
A stator 5 is fixed to the inner peripheral surface of the cylindrical front housing 2. The stator 5 has a cylindrical stator core 11, and the outer peripheral surface of the stator core 11 is fixed to the inner side surface of the cylindrical front housing 2. Inside the stator core 11, a plurality of teeth 12 formed along the axial direction and arranged at equal pitches in the circumferential direction are formed extending radially inward (see FIG. 2). Each tooth 12 is a T-shaped tooth, and the inner circumferential surface in the radial direction is an arc surface obtained by extending a concentric arc in the axial direction around the central axis O of the rotating shaft 6.

  A three-phase winding (V-phase winding 15 in FIG. 1) is wound around each tooth 12 via an insulator 13. Specifically, as shown in FIG. 2, twelve teeth 12 have three-phase windings in the circumferential direction, that is, a U-phase winding 14, a V-phase winding 15, and a W-phase winding 16 in order. It is wound by concentrated winding. Then, a three-phase drive current is supplied to each of the wound phase windings 14, 15, 16 to form a rotating magnetic field in the stator 5, and the rotor fixed to the rotating shaft 6 disposed inside the stator 5. 7 is rotated forward and backward.

[Rotor 7]
As shown in FIGS. 1 and 2, the rotor 7 fixed to the rotating shaft 6 is disposed inside the stator 5.

As shown in FIG. 4, the rotor 7 includes first and second rotor cores 20 and 30 and a field magnet 40.
[First rotor core 20]
The first rotor core 20 is formed of an electromagnetic steel plate made of a soft magnetic material and is disposed on the end frame 3 side. The first rotor core 20 has a disk-shaped first core base 21, and a through hole 21 a is formed through the center position thereof. A substantially cylindrical boss portion 21e is formed to protrude from the outer peripheral portion of the through hole 21a on the end frame 3 side. In the present embodiment, the through hole 21a and the boss portion 21e are formed simultaneously by burring. The outer diameter of the boss portion 21e is shorter than the outer diameter of the bearing 9 that rotatably supports one side of the rotating shaft 6, that is, the inner diameter of the bearing holding portion 3a that accommodates and fixes the bearing 9 provided on the end frame 3. Is formed.

  The rotary shaft 6 is press-fitted into the through hole 21a (boss portion 21e), and the first core base 21 is fixed to the rotary shaft 6 by pressure. At this time, the first core base 21 is firmly pressure-bonded and fixed to the rotating shaft 6 by forming the boss portion 21e. When the first core base 21 is pressure-bonded and fixed to the rotating shaft 6, the boss portion 21e is arranged so as to be separated from the bearing 9 accommodated and fixed in the bearing holding portion 3a in the axial direction. (See FIG. 1).

  On the outer peripheral surface 21d of the first core base 21, a plurality of (four in the present embodiment) first claw-shaped magnetic poles 22 project radially outward and extend in the axial direction at equal intervals. Here, in the first claw-shaped magnetic pole 22, a portion protruding radially outward from the outer peripheral surface 21 d 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. That's it.

  The circumferential end surfaces 22a and 22b of the first claw-shaped magnetic pole 22 composed of the first base portion 23 and the first magnetic pole portion 24 extend in the radial direction (not inclined with respect to the radial direction when viewed from the axial direction). It has become. The circumferential angle of each first claw-shaped magnetic pole 22, that is, the angle between the circumferential end surfaces 22 a and 22 b is set smaller than the angle of the gap between the first claw-shaped magnetic poles 22 adjacent in the circumferential direction. Yes.

  Further, the radially outer surface f1 of the first magnetic pole portion 24 has a concentric circular arc surface in which the cross-sectional shape in the direction perpendicular to the axis is centered on the central axis O of the rotating shaft 6, and the first radially outer surface f1 There are two grooves, an auxiliary groove 25 and a second auxiliary groove 26. The first and second auxiliary grooves 25 and 26 are formed at positions shifted by the same angle on both sides from the circumferential center of the radially outer surface f1. The first and second auxiliary grooves 25 and 26 are formed in a U-shaped cross section in the direction perpendicular to the axis.

  On the opposite surface 21 b of the first core base 21, four positioning locking holes 27 are formed so as to penetrate at an equiangular interval on a concentric circle centered on the central axis O. The four positioning locking holes 27 are formed at an intermediate position between the adjacent first claw-shaped magnetic poles 22 formed in the first core base 21.

[Second rotor core 30]
As shown in FIG. 4, the second rotor core 30 has the same material and the same shape as the first rotor core 20, and is disposed on the cylindrical front housing 2 side. The second rotor core 30 has a disk-shaped second core base 31, and a through hole 31 a is formed through the center of the second rotor core 30.

  As shown in FIGS. 1 and 4, a substantially cylindrical boss 31 e protrudes from the outer peripheral portion of the through hole 31 a on the cylindrical front housing 2 side. In the present embodiment, the through hole 31a and the boss portion 31e are formed simultaneously by burring. The outer diameter of the boss portion 31e is the outer diameter of the bearing 8 that rotatably supports the other side of the rotating shaft 6, that is, the inner diameter of the bearing holding portion 2a that accommodates and fixes the bearing 8 provided with the cylindrical front housing 2. It is formed shorter.

  The rotary shaft 6 is press-fitted into the through hole 31a (boss portion 31e), and the second core base 31 is fixed to the rotary shaft 6 by pressure. At this time, the second core base 31 is firmly pressure-bonded to the rotating shaft 6 by forming the boss portion 31e. When the second core base 31 is pressure-bonded and fixed to the rotary shaft 6, the boss portion 31e is arranged so as to be separated from the bearing 8 accommodated and fixed in the bearing holding portion 2a in the axial direction. It has become.

  As shown in FIG. 4, on the outer peripheral surface 31d of the second core base 31, four second claw-shaped magnetic poles 32 project radially outward and extend in the axial direction at equal intervals. Here, in the second claw-shaped magnetic pole 32, a portion protruding radially outward from the outer peripheral surface 31 d of the second core base 31 is referred to as a second base portion 33, and a tip portion bent in the axial direction is the second magnetic pole portion 34. That's it.

  The circumferential end surfaces 32a and 32b of the second claw-shaped magnetic pole 32 composed of the second base portion 33 and the second magnetic pole portion 34 are flat surfaces extending in the radial direction. The circumferential angle of each of the second claw-shaped magnetic poles 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 poles 32 adjacent in the circumferential direction. Yes.

  Further, the radially outer surface f2 of the second magnetic pole portion 34 has a concentric circular arc surface whose center is perpendicular to the central axis O of the rotating shaft 6, and the first outer surface f2 thereof There are two grooves, an auxiliary groove 35 and a second auxiliary groove 36. The first and second auxiliary grooves 35 and 36 are formed at positions shifted by the same angle on both sides from the circumferential center of the radially outer surface f1. Further, the first and second auxiliary grooves 35 and 36 are formed in a U-shaped cross section in the direction perpendicular to the axis.

  The second rotor core 30 is disposed between the first claw-shaped magnetic poles 22 to which the second claw-shaped magnetic poles 32 respectively correspond. At this time, the second rotor core 30 is assembled to the first rotor core 20 such that the field magnet 40 is disposed between the first core base 21 and the second core base 31 in the axial direction.

[Field magnet 40]
As shown in FIG. 4, the field magnet 40 is a disk-like permanent magnet, and a through hole 40 a is formed at the center thereof. The field magnet 40 is, for example, an anisotropic sintered magnet, and is composed of, for example, a ferrite magnet, a samarium cobalt (SmCo) magnet, a neodymium magnet, or the like.

  The field magnet 40 has a cylindrical sleeve 41 inserted through the through hole 40a. The sleeve 41 is made of a non-magnetic material and is made of the same stainless steel as the rotary shaft 6 in this embodiment. Note that the axial length of the sleeve 41 is slightly longer than the axial thickness of the field magnet 40 in this embodiment. The outer diameter of the sleeve 41 is smaller than the inner diameter of the through hole 40a of the field magnet 40, and is larger than the outer diameter of the boss portions 21e and 31e. Accordingly, the inner diameter of the through hole 40a of the field magnet 40 is larger than the outer diameter of the boss portions 21e and 31e.

  The outer peripheral surface of the sleeve 41 and the inner peripheral surface of the through hole 40a of the field magnet 40 are bonded and fixed with an adhesive made of a curable resin that does not allow magnetic flux to pass. Specifically, after the sleeve 41 is inserted into the rotary shaft 6 without being press-fitted, the through hole 40 a of the field magnet 40 is inserted into the sleeve 41. At this time, an adhesive made of a curable resin is applied to the inner peripheral surface of the through hole 40a and inserted. As a result, the field magnet 40 is bonded and fixed to the sleeve 41 as the adhesive is cured.

  The outer diameter of the field magnet 40 is set to coincide with the outer diameters of the first and second core bases 21 and 31. Therefore, the outer peripheral surface 40 b of the field magnet 40 is flush with the outer peripheral surfaces 21 d and 31 d of the first and second core bases 21 and 31.

  The field magnet 40 is magnetized in the axial direction, and is magnetized 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). Yes. Therefore, by this field magnet 40, the first claw-shaped magnetic pole 22 of the first rotor core 20 functions as an N pole (first magnetic pole), and the second claw-shaped magnetic pole 32 of the second rotor core 30 functions as an S pole (second magnetic pole). Function as a magnetic pole).

  Therefore, the rotor 7 of the present embodiment is a so-called Landel type rotor using the field magnet 40. In the rotor 7, first claw-shaped magnetic poles 22 that are N poles and second claw-shaped magnetic poles 32 that are S poles are alternately arranged in the circumferential direction, and the number of magnetic poles is eight.

  That is, in the brushless motor M of this embodiment, the number of poles of the rotor 7 is set to 2 × n (where n is a natural number), and the number of teeth 12 of the stator 5 is set to 3 × n. The number of poles of the rotor 7 is set to “8”, and the number of teeth 12 of the stator 5 is set to “12”.

[Rectifier magnet 42]
As shown in FIG. 4, the rotor 7 includes an annular rectifier magnet 42 that is fixed to the outer peripheral surface 40 b of the field magnet 40 by, for example, adhesion. The rectifying magnet 42 has axial end faces 42 a and 42 b that form one flat surface, and the axial end faces 42 a and 42 b are parallel to each other perpendicular to the central axis O of the rotating shaft 6. ing. Further, the inner peripheral surface 42c and the outer peripheral surface 42d of the rectifying magnet 42 have a circular shape centered on the central axis O of the rotating shaft 6 when viewed in the axial direction. That is, the rectifying magnet 42 is formed so that there are no irregularities on the axial end faces 42a and 42b, the inner peripheral face 42c and the outer peripheral face 42d. The rectifying magnet 42 is a sintered magnet formed by, for example, sintering, and is composed of, for example, a ferrite magnet, a samarium cobalt (SmCo) magnet, a neodymium magnet, or the like.

  The rectifying magnet 42 having the above-described shape is a polar anisotropic magnet having a sinusoidal magnetic flux density distribution in the circumferential direction of the outer peripheral surface 42d. More specifically, in the rectifying magnet 42, an N pole portion 42n where the N pole appears on the outer peripheral surface 42d and an S pole portion 42s where the S pole appears on the outer peripheral surface 42d are alternately set at equal intervals in the circumferential direction. The number of poles of the rectifying magnet 42 matches the number of poles of the rotor 7 (eight poles in the present embodiment). The N pole portion 42n and the S pole portion 42s are magnetized so that the magnetic flux faces in the radial direction on the outer peripheral side, and the interpole portions 42m between the N pole portions 42n and the S pole portions 42s The direction component is mainly magnetized.

  In the rectifying magnet 42, each N pole portion 42 n has each first claw-shaped magnetic pole 22, each S pole portion 42 s has each second claw-shaped magnetic pole 32, and each pole portion 42 m has the first claw-shaped magnetic pole 22 and the second claw-shaped magnetic pole 22. The claw-shaped magnetic poles 32 are assembled so as to correspond to each other in the circumferential direction. That is, each N pole portion 42 n of the rectifying magnet 42 is disposed between the back surface (radially inner surface) of the first magnetic pole portion 24 of each first claw-shaped magnetic pole 22 and the outer peripheral surface 40 b of the field magnet 40. . The N pole portion 42n is mainly magnetized with a radial component so that the contact surface X1 (outer peripheral surface) that contacts the back surface of the first magnetic pole portion 24 becomes the same N pole as the first magnetic pole portion 24. Has been. That is, the N pole portion 42n is magnetized so that a magnetic flux is generated along the radial direction on the contact surface X1.

  Further, each S pole portion 42 s of the rectifying magnet 42 is disposed between the back surface (radially inner side surface) of the second magnetic pole portion 34 of each second claw-shaped magnetic pole 32 and the outer peripheral surface 40 b of the field magnet 40. . The S pole portion 42s mainly magnetizes the radial component so that the contact surface X2 (outer peripheral surface) that contacts the back surface of the second magnetic pole portion 34 becomes the S pole having the same polarity as the second magnetic pole portion 34. Has been. That is, the S pole portion 42s is magnetized so that a magnetic flux is generated along the radial direction on the contact surface X2.

  Each inter-pole portion 42m corresponding to the circumferential direction between the first claw-shaped magnetic pole 22 and the second claw-shaped magnetic pole 32 has a first claw-shaped magnetic pole 22 side as the N pole and the second claw-shaped magnetic pole 32 in the circumferential direction. The circumferential component is mainly magnetized so that the side becomes the S pole.

[Support plate 51 and sensor magnet 60]
As shown in FIGS. 1 and 3, a support plate 51 that holds the sensor magnet 60 is fixed to the end surface of the rotor 7 on the end frame 3 side (the opposite surface 21 b of the first core base 21). The support plate 51 is made of a nonmagnetic material (brass in this embodiment).

  As shown in FIG. 3, the support plate 51 has a disk-like base portion 53. The base portion 53 is formed with a through window 53a through which the rotary shaft 6 passes at the center thereof. On the surface of the base portion 53 on the first rotor core 20 side, four first locking projections 54 are formed by pressing so as to protrude at equal angular intervals. Each first locking projection 54 is fitted into each positioning locking hole 27 formed on the opposite surface 21 b of the first core base 21. At this time, the base portion 53 abuts against the opposite surface 21 b of the first core base 21 in the axial direction.

  A cylindrical wall 55 is formed on the outer peripheral edge portion of the base portion 53 so as to extend in the axial direction toward the side opposite to the rotor 7 (end frame 3 side). The outer diameter of the cylindrical wall 55 is formed substantially equal to the outer shape of the rotor 7.

  A ring-shaped sensor magnet 60 is provided on the inner peripheral surface of the cylindrical wall 55. The sensor magnet 60 has an outer surface in the radial direction fixed to the inner peripheral surface of the cylindrical wall 55 with an adhesive. At this time, the sensor magnet 60 is fixed to the support plate 51 so that the center axis of the ring-shaped sensor magnet 60 coincides with the center axis O of the rotating shaft 6. Thus, the sensor magnet 60 is configured to be able to rotate integrally with the rotary shaft 6 and the rotor 7 at the axial side position of the rotor 7.

  In the sensor magnet 60, the N pole and the S pole are alternately magnetized at equal angular intervals in the circumferential direction. More specifically, the magnetic pole on the first rotor core 20 side of the sensor magnet 60 has an N pole on the side facing the first claw-shaped magnetic pole 22 in the axial direction and an S pole on the side facing the second claw-shaped magnetic pole 32 in the axial direction. It is magnetized so that That is, the magnetic poles on the first rotor core 20 side of the ring-shaped sensor magnet 60 are the N pole portion 60n magnetized to the N pole and the S pole portion 60s magnetized to the S pole. Magnetized so as to correspond to the magnetic pole of the two-claw magnetic pole 32.

  As shown in FIG. 1, the sensor magnet 60 is disposed on the outer side in the radial direction of the bearing holding portion 3 a that protrudes from the axial inner side surface 3 b (end surface on the rotor 7 side) of the end frame 3 to the rotor 7 side. In other words, the bearing holding portion 3 a is configured such that a part thereof is disposed on the inner peripheral side of the ring-shaped sensor magnet 60. The bearing holding portion 3a faces the base portion 53 of the support plate 51 in the axial direction, and the bearing holding portion 3a of the end frame 3 faces the sensor magnet 60 in the axial direction.

[Magnetic sensor 62]
A magnetic sensor 62 such as a Hall IC that is opposed to the sensor magnet 60 at a certain interval in the axial direction is supported on the inner side surface 3 b in the axial direction of the end frame 3. The magnetic sensor 62 may be directly fixed to the end frame 3 or may be indirectly held with respect to the end frame 3 via a holding member (not shown).

  When the rotor 7 rotates, in the sensor magnet 60, the N pole portion 60n magnetized to the N pole and the S pole portion 60s magnetized to the S pole alternately pass in front of the magnetic sensor 62. With this rotation, the magnetic sensor 62 detects that the N pole portion 60n and the S pole portion 60s of the sensor magnet 60 pass alternately.

  The magnetic sensor 62 outputs the detection signal to a control circuit (not shown). The control circuit calculates the rotation angle (rotation position) of the rotor 7 based on the detection signal from the magnetic sensor 62 and calculates the rotation speed. Then, the control circuit performs drive control of the brushless motor M using the calculated rotation angle (rotation position) and rotation speed.

Next, the operation of this embodiment will be described.
When a three-phase drive current is supplied to the phase windings 14, 15, 16 of the stator core 11 to form a rotating magnetic field in the stator 5, the rotor 7 fixed to the rotating shaft 6 disposed inside the stator 5 is It rotates based on the rotating magnetic field.

  At this time, in the rotor 7, radial magnetic flux leakage between the first magnetic pole portion 24 of the first claw-shaped magnetic pole 22 and the field magnet 40 is suppressed by the magnetic action of the N pole portion 42 n of the rectifying magnet 42. Yes. Further, the leakage magnetic flux in the radial direction between the second magnetic pole portion 34 of the second claw-shaped magnetic pole 32 and the field magnet 40 is suppressed by the magnetic action of the S pole portion 42 s of the rectifying magnet 42. And the leakage magnetic flux of the circumferential direction between the 1st and 2nd magnetic pole parts 24 and 34 adjacent to the circumferential direction is suppressed by the magnetic effect | action of the pole part 42m of the rectifier magnet 42. FIG. As a result, the magnetic flux of the rotor 7 is rotationally driven by acting with the rotating magnetic field of the stator 5 with high efficiency. As a result, the output of the brushless motor M is improved.

Next, characteristic effects of the present embodiment will be described.
(1) An annular rectifier magnet 42 arranged so as to pass between the radial direction of the field magnet 40 and the first and second claw-shaped magnetic poles 22 and 32 (first and second magnetic pole portions 24 and 34) The axial end surfaces 42a and 42b are each one flat surface, and the inner peripheral surface 42c and the outer peripheral surface 42d are circular in the axial direction view. As a result, the rectifying magnet 42 has a simple shape with no irregularities on the axial end faces 42a and 42b, the inner peripheral surface 42c, and the outer peripheral surface 42d. In some cases, it can be easily molded. That is, the molding method of the rectifying magnet 42 and the degree of freedom in selecting the material are improved.

  For example, when a sintered magnet is used for the rectifying magnet 42, since it does not contain a binder such as rubber or resin contained in the bond magnet, it is advantageous in terms of improving magnetic characteristics, and when obtaining equivalent magnetic characteristics. In addition, it can be manufactured at a lower cost than a bonded magnet. In addition, since the sintered magnet has higher rigidity than the bonded magnet, the strength can be easily secured even if the size of the sintered magnet is reduced, and it is possible to contribute to the downsizing of the rotor 7 and the cost reduction associated with the downsizing.

  The rectifying magnet 42 is in contact with the back surfaces of the first and second claw-shaped magnetic poles 22 and 32 (first and second magnetic pole portions 24 and 34), respectively. 42s) is magnetized so that a magnetic flux is generated along the radial direction, and a circumferential component is mainly magnetized at a portion corresponding to the circumferential direction of the first and second claw-shaped magnetic poles 22 and 32 (interpolar portion 42m). Magnetized. Thereby, the magnetic action at the contact surfaces X1 and X2 of the N pole portion 42n and the S pole portion 42s of the rectifier magnet 42 causes the first and second claw-shaped magnetic poles 22 and 32 and the field magnet 40 to be connected. It becomes possible to suppress the leakage magnetic flux, and it is possible to suppress the leakage magnetic flux between the first and second claw-shaped magnetic poles 22 and 32 adjacent to each other in the circumferential direction by the magnetic action at the interpole portion 42m of the rectifying magnet 42. .

  Further, the outer peripheral surface 42d of the rectifying magnet 42 is circular as viewed in the axial direction, and the outer peripheral surface 42d does not have a convex portion that enters between the circumferential directions of the first and second claw-shaped magnetic poles 22 and 32. For this reason, high dimensional accuracy in consideration of the clearance in the circumferential direction with the first and second claw-shaped magnetic poles 22 and 32 is not required, and it is possible to contribute to a reduction in manufacturing cost.

In addition, you may change the said embodiment as follows.
In the above embodiment, the rectifying magnet 42 is a sintered magnet formed by sintering molding. However, other than this, for example, a bonded magnet (compression molding bonded magnet) that is compression molded using a thermosetting resin as a binder. It is good. Compression molded bond magnets can reduce the resin ratio compared to injection molded bond magnets, which is advantageous in terms of improving magnetic properties, and can be manufactured at a lower cost than injection molded bond magnets when obtaining equivalent magnetic properties. . In addition, since the compression-molded bond magnet has higher rigidity than the injection-molded bond magnet in which a thermoplastic resin is used for the binder, the strength can be easily secured even if the physique is reduced, and the rotor 7 can be downsized. As a result, it can contribute to the cost reduction accompanying the miniaturization.

  In the above embodiment, the brushless motor M is used as a drive source for the variable valve timing device. However, it is needless to say that the brushless motor M may be used as a drive source for other devices (for example, a throttle valve control device).

  M ... brushless motor, 5 ... stator, 6 ... rotating shaft, 7 ... rotor (Landel type rotor), 20 ... first rotor core, 22 ... first claw-shaped magnetic pole, 30 ... second rotor core, 32 ... second claw-shaped magnetic pole , 40 ... field magnets, 42 ... rectifying magnets, X1, X2 ... contact surfaces.

Claims (2)

First and second rotor cores each having a plurality of claw-shaped magnetic poles in the circumferential direction and assembled in a manner in which the claw-shaped magnetic poles alternate in the circumferential direction;
The claw-shaped magnetic pole of the first rotor core functions as a first magnetic pole by being arranged between the axial directions of the first and second rotor cores and magnetized in the axial direction, and the claw of the second rotor core A field magnet that functions as a second magnetic pole,
An annular rectifier magnet disposed so as to pass between the radial direction of the field magnet and each claw-shaped magnetic pole,
The rectifier magnets each have one flat end surface in the axial direction, the inner peripheral surface and the outer peripheral surface have a circular shape when viewed in the axial direction, and the contact surface that contacts the back surface of each claw-shaped magnetic pole has a radial direction. A Landel rotor characterized by being magnetized so that a magnetic flux is generated along a magnetic field, and having a circumferential component mainly magnetized at portions corresponding to the claw-shaped magnetic poles.   A motor comprising the Landel rotor according to claim 1 and a stator that generates a rotating magnetic field.