JP2022071593A - Rotor, motor, and brushless wiper motor - Google Patents

Abstract

To provide a rotor that can be easily manufactured and can suppress demagnetization of a magnet due to interlinkage magnetic flux of a stator coil while suppressing increase in a manufacturing cost, a motor, and a brushless wiper motor.SOLUTION: A rotor includes: a shaft 31; a rotor core 32; a plurality of permanent magnets 33 arranged side by side in a circumferential direction on an outer peripheral surface 32b of the rotor core 32; and a salient pole 35 projecting outward in a radial direction of the rotor core 32 between the permanent magnets 33 adjacent to each other in a circumferential direction of the outer peripheral surface 32b of the rotor core 32. The permanent magnet 33 has a first region R1 on a circumferential direction central side and a second region R2 on the salient pole 35 side while sandwiching a second straight line L2 passing through an intersection K of the straight line that is in parallel with a first line passing through a circumferential center of the permanent magnet 33 and an axial center seen from an axial direction and along a side surface 35c of the salient pole 35 and a curved line LK along the outer peripheral surface 32b of the rotor core 32. A magnetization orientation of at least a part of the second region R2 is radial orientation that is a direction along a radial direction.SELECTED DRAWING: Figure 4

Description

The present invention relates to a rotor, a motor and a brushless wiper motor.

Conventionally, as a surface magnet (SPM: Surface Permanent Magnet) type rotor having a permanent magnet for a field magnet on the surface of the rotor core, it is provided with a protrusion protruding outward in the radial direction between the permanent magnets arranged in the circumferential direction. Inset type rotors are known. In this rotor, the rotor core and the protrusions are made of a magnetic material. The protrusion of the rotor core generates a relaxation torque that rotates the rotor core so that the protruding direction is the direction in which the interlinkage magnetic flux due to the coil of the stator easily flows and the magnetic resistance (reluctance) of the magnetic path of the interlinkage magnetic flux is reduced. ..

By the way, in such a rotor, the interlinkage magnetic flux due to the coil of the stator tends to flow so as to be attracted toward the protrusion of the rotor core, so that it is inside the magnet at both ends in the circumferential direction of the permanent magnet. It may invade and generate a demagnetizing field inside the magnet. Therefore, it is desired to suppress demagnetization of the permanent magnet due to the interlinkage magnetic flux of the coil of the stator. Various techniques for suppressing the demagnetization of this permanent magnet are disclosed.
For example, a technique is disclosed in which a magnetic coercive portion having a larger intrinsic coercive force than other portions is provided at both ends of a permanent magnet in the circumferential direction (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2020-78176

However, in order to actually provide the above-mentioned holding portions at both ends in the circumferential direction of the permanent magnet, it may be necessary to change the material between the other portions and the holding portion. As described above, it becomes difficult to manufacture permanent magnets, and there is a possibility that the manufacturing cost will increase.

Therefore, the present invention provides a rotor, a motor, and a brushless wiper motor that can be easily manufactured and can suppress an increase in manufacturing cost while suppressing demagnetization of a magnet due to the interlinkage magnetic flux of the stator coil.

In order to solve the above problems, the rotor according to the present invention includes a shaft that rotates around the axis of rotation, a rotor core that holds the shaft and rotates about the axis of rotation in the radial direction, and an outer peripheral surface of the rotor core. A plurality of magnets arranged side by side along the circumferential direction, and a salient pole protruding outward in the radial direction of the rotor core between the magnets adjacent to each other in the circumferential direction of the outer peripheral surface of the rotor core. The plurality of the magnets are parallel to the first straight line passing through the circumferential center of the magnet and the rotational axis when viewed from the rotational axis direction, and the straight line along the circumferential side surface of the salient pole and the rotor core. It has a first region on the central side in the circumferential direction and a second region on the salient pole side with a second straight line passing through an intersection with a curve along the outer peripheral surface of the above. The orientation is characterized by a radial orientation that is along the radial direction.

The motor according to the present invention has an annular stator core, a stator having a plurality of teeth protruding inward in the radial direction from the inner peripheral surface of the stator core, a coil mounted on the teeth, and the plurality of teeth. The rotor according to the above description is provided inside the radial direction.

The brushless wiper motor according to the present invention is characterized by including the motor described above as a drive source for a wiper mounted on a vehicle.

According to the present invention, it is possible to suppress demagnetization of a magnet due to the interlinkage magnetic flux of the stator coil while being easily manufactured and suppressing an increase in manufacturing cost.

FIG. 3 is a perspective view of a brushless wiper motor according to an embodiment of the present invention. FIG. 6 is a cross-sectional view taken along the line AA of FIG. FIG. 3 is a sectional view taken along the radial direction of the stator and the rotor according to the embodiment of the present invention. FIG. 3 is an enlarged view of part B. An explanatory diagram showing an example of the flow of the interlinkage magnetic flux to the salient pole of the rotor according to the embodiment of the present invention. The graph which shows the change of the demagnetization rate of a permanent magnet in embodiment of this invention. The graph which compared the case where the magnetization orientation of a permanent magnet in the embodiment of this invention was a parallel orientation, and the case where it was a radial orientation.

Hereinafter, the rotor, the motor, and the brushless wiper motor according to the embodiment of the present invention will be described with reference to the accompanying drawings.

<Brushless wiper motor>
FIG. 1 is a perspective view of the brushless wiper motor 1. FIG. 2 is a cross-sectional view taken along the line AA of FIG.
As shown in FIGS. 1 and 2, the brushless wiper motor 1 is, for example, a drive source for a wiper mounted on a vehicle. The brushless wiper motor 1 includes a motor unit (an example of a motor in the claim) 2, a deceleration unit 3 that decelerates and outputs the rotation of the motor unit 2, and a controller unit 4 that controls the drive of the motor unit 2. ..
In the following description, the term "axial direction" refers to the rotation axis direction of the shaft 31 of the motor unit 2, and the term "circumferential direction" refers to the circumferential direction of the shaft 31 (rotation direction of the rotor 9 described later). , The term simply radial means the radial direction of the shaft 31.

<Motor section>
The motor unit 2 is provided with a motor case 5, a substantially cylindrical stator 8 housed in the motor case 5, and a rotor 9 provided radially inside the stator 8 and rotatably provided with respect to the stator 8. And. The motor unit 2 is a so-called brushless motor that does not require a brush to supply electric power to the stator 8.

<Motor case>
The motor case 5 is made of a material having excellent heat dissipation, such as aluminum die-cast. The motor case 5 includes a first motor case 6 and a second motor case 7 which are configured to be rotatable in the axial direction. The first motor case 6 and the second motor case 7 are each formed in a bottomed cylindrical shape.
The first motor case 6 is integrally molded with the gear case 40 so that the bottom portion 10 is joined to the gear case 40 of the deceleration portion 3. A through hole 10a through which the shaft 31 of the rotor 9 can be inserted is formed at substantially the center of the bottom portion 10 in the radial direction.

Further, an outer flange portion 16 projecting outward in the radial direction is formed in the opening portion 6a of the first motor case 6. An outer flange portion 17 projecting outward in the radial direction is formed in the opening portion 7a of the second motor case 7. The outer flange portions 16 and 17 are butted against each other to form a motor case 5 having an internal space. In the internal space of the motor case 5, the stator 8 is arranged so as to be fitted inside the first motor case 6 and the second motor case 7.

<Stator>
FIG. 3 is a cross-sectional view taken along the radial direction of the stator 8 and the rotor 9.
As shown in FIGS. 2 and 3, the stator 8 has a cylindrical core portion 21 and a plurality of teeth (for example, six in the present embodiment) protruding inward in the radial direction from the core portion 21. 22 and an annular stator core 20 integrally molded.
The stator core 20 is formed by laminating a plurality of metal plates in the axial direction. The stator core 20 is not limited to the case where a plurality of metal plates are laminated in the axial direction, and may be formed, for example, by pressure molding soft magnetic powder.

The teeth 22 includes an integrally molded teeth body 22a and a pair of flanges 22b. The tooth body 22a projects inward along the radial direction from the inner peripheral surface of the core portion 21. The flange portion 22b extends along the circumferential direction from the radial inner end of the tooth body 22a. The pair of flange portions 22b are formed so as to extend outward in the circumferential direction from the tooth body 22a. Then, a dovetail groove-shaped slot 19 is formed between the flange portions 22b adjacent to each other in the circumferential direction.

Further, the inner peripheral surface of the core portion 21 and the teeth 22 are covered with a resin insulator 23. A coil 24 is wound around each tooth 22 from above the insulator 23. Each coil 24 generates a magnetic field for rotating the rotor 9 by supplying power from the controller unit 4.

<Rotor>
The rotor 9 is rotatably provided inside the stator 8 via a minute gap.
The rotor 9 covers the shaft 31, the rotor core 32 fixed to the shaft 31, the four permanent magnets (an example of the magnet in the claim) 33 fixed to the rotor core 32, and the rotor core 32 and the permanent magnet 33 from the surroundings. A cylindrical magnet cover 70 is provided. As described above, in the motor unit 2, the ratio of the number of magnetic poles of the permanent magnet 33 to the number of slots 19 (teeth 22) is, for example, 4: 6.

The rotor 9 rotates with the center line (axis center) C1 of the shaft 31 as the rotation axis and the rotation axis as the radial center.
The shaft 31 is integrally molded with the worm shaft 44 (see FIG. 2) constituting the deceleration unit 3.
The rotor core 32 is fixed so as to be fitted to the outside of the shaft 31. The rotor core 32 is formed in a columnar shape with the shaft 31 as the axis C1.

The rotor core 32 is formed by laminating a plurality of metal plates in the axial direction. The rotor core 32 is not limited to the case where a plurality of metal plates are laminated in the axial direction, and may be formed, for example, by pressure molding soft magnetic powder.

A through hole 32a penetrating in the axial direction is formed substantially in the center of the rotor core 32 in the radial direction. The shaft 31 is press-fitted into the through hole 32a. The shaft 31 may be relatively inserted into the through hole 32a so that the rotor core 32 is fitted on the outer peripheral surface of the shaft 31. In this case, the shaft 31 and the rotor core 32 may be fixed by an adhesive or the like.
In the rotor core 32, the arc center of the inner peripheral surface (that is, the inner peripheral surface of the through hole 32a) on the inner side in the radial direction and the arc center on the outer peripheral surface 32b on the outer side in the radial direction coincide with the position of the axis C1 of the shaft 31.

Further, four salient poles 35 are provided on the outer peripheral surface 32b of the rotor core 32 at equal intervals in the circumferential direction. The salient pole 35 is formed so as to protrude outward in the radial direction integrally with the rotor core 32 and extend over the entire axial direction of the rotor core 32. A round chamfered portion 32c is formed at the connection portion between the base end (diameter inner end) of the salient pole 35 and the outer peripheral surface 32b of the rotor core 32. The salient pole 35 is formed by laminating a plurality of metal plates in the axial direction in the same manner as the rotor core 32.

In the outer peripheral surface 32b of the rotor core 32 formed in this way, the space between the two salient poles 35 adjacent to each other in the circumferential direction is configured as a magnet accommodating portion 36, respectively.
That is, the rotor 9 is a surface magnet (SPM: Surface Permanent Magnet) type rotor having a field permanent magnet 33 on the outer peripheral surface 32b of the rotor core 32, and the rotor core 32 is located between the permanent magnets 33 arranged in the circumferential direction. It is an inset type rotor provided with a salient pole 35 protruding outward in the radial direction.

Further, a recess 38 extending in the axial direction is formed on the tip surface (end surface on the outer side in the radial direction) 35a of the salient pole 35. Further, on the tip surface 35a of the salient pole 35, round chamfered portions 35b are formed at the corners on both sides in the circumferential direction. Further, the salient pole 35 is formed so that two side surfaces 35c facing each other in the circumferential direction are parallel to each other in the projecting direction. That is, the salient pole 35 is formed so that the width dimension in the circumferential direction is uniform in the protruding direction.

<Permanent magnet>
FIG. 4 is an enlarged view of part B of FIG.
As shown in FIGS. 3 and 4, the four permanent magnets 33 are arranged in the four magnet storage portions 36 provided on the outer peripheral surface 32b of the rotor core 32. Each permanent magnet 33 is fixed to the rotor core 32 in the magnet accommodating portion 36, for example, with an adhesive or the like.

The permanent magnet 33 is, for example, a ferrite magnet or a rare earth magnet. The permanent magnet 33 is formed in a tile shape. In the permanent magnet 33, the arc center Ci of the inner peripheral surface 33b on the inner side in the radial direction coincides with the position of the axial center C1 of the shaft 31. The arc center Co of the outer peripheral surface 33a on the outer peripheral surface in the radial direction is eccentric with respect to the axial center C1 of the shaft 31. Specifically, the arc center Co of the outer peripheral surface 33a of the permanent magnet 33 is set closer to the outer peripheral surface 32b of the rotor core 32 than the axial center C1 in the radial direction passing through the center of the permanent magnet 33.

As a result, in the permanent magnet 33, the radial thickness at the end portions 33s on both sides in the circumferential direction around the axial center C1 of the shaft 31 becomes smaller than the radial thickness at the circumferential central portion 33c. Along with this, the gap between the radial outer outer peripheral surface 33a of the permanent magnet 33 and the inner peripheral surface of the teeth 22 is the smallest in the circumferential central portion 33c of the permanent magnet 33, and is circumferential from the circumferential central portion 33c. It changes to an increasing tendency as it moves away from the outside of the direction.

The inner peripheral surface 33b of the permanent magnet 33 is in contact with almost the entire outer peripheral surface 32b of the rotor core 32. Further, each circumferential side surface 33d on both sides of the permanent magnet 33 is in contact with the side surface 35c of the salient pole 35. The circumferential side surface 33d is smoothly connected to the inner peripheral surface 33b on the inner side in the radial direction via the arc surface 33f. The radius of curvature of the arcuate surface 33f is larger than the radius of curvature of the round chamfered portion 32c formed at the connection portion between the outer peripheral surface 32b of the rotor core 32 and the base end of the salient pole 35. Therefore, the arc surface 33f and the round chamfered portion 32c do not come into contact with each other. Therefore, the inner peripheral surface 33b of the permanent magnet 33 is surely brought into contact with the outer peripheral surface 32b of the rotor core 32. Further, the peripheral side surface 33d of the permanent magnet 33 is surely brought into contact with the side surface 35c of the salient pole 35.

Next, the magnetization orientation of the permanent magnet 33 will be described in detail.
The permanent magnet 33 has two regions R1 and R2 (first region R1 and second region R2) having different magnetization orientations.
Here, the two regions R1 and R2 will be described. The straight line passing through the central portion 33c in the circumferential direction of the permanent magnet 33 and the axial center C1 when viewed from the axial direction is defined as the first straight line L1. The straight line along the side surface 35c of the salient pole 35 is defined as a complementary straight line Lh. Let Lk be a curve along the outer peripheral surface 32b of the rotor core 32. The intersection of the complementary straight line Lh and the curve Lk is defined as the intersection point C2. A straight line passing through the intersection C2 and parallel to the first straight line L1 is referred to as a second straight line L2.

In the permanent magnet 33, the region on the circumferential central portion 33c side about the second straight line L2 is set in the first region R1. A region on the salient pole 35 side centered on the second straight line L2 is set in the second region R2. That is, one permanent magnet 33 has one first region R1 and two second regions R2 arranged on both sides in the circumferential direction with the second straight line L2 interposed therebetween. When viewed from the axial direction, the first region R1 is a substantially rectangular region, and the second region R2 is a substantially triangular region that tapers inward in the radial direction.
The entire first region R1 is a parallel orientation in which the magnetization orientation is parallel to the first straight line L1 (see arrow PM in FIG. 4). On the other hand, the entire second region R2 is a radial orientation in which the magnetization orientation is in the radial direction (see the arrow RM in FIG. 4).

The permanent magnets 33 configured in this way are arranged so that the magnetic orientations of the permanent magnets 33 adjacent to each other in the circumferential direction are opposite to each other. That is, the four permanent magnets 33 are arranged so that the magnetic poles are staggered in the circumferential direction. In other words, the permanent magnet 33 having the N pole on the outer peripheral side and the permanent magnet 33 having the S pole on the outer peripheral side are arranged so as to be adjacent to each other in the circumferential direction. As a result, the salient pole 35 of the rotor core 32 arranged between the permanent magnets 33 adjacent to each other in the circumferential direction is located at the boundary (pole boundary) of the magnetic poles.

<Deceleration part>
Returning to FIGS. 1 and 2, the deceleration unit 3 includes a gear case 40 to which the motor case 5 is attached, and a worm deceleration mechanism 41 housed in the gear case 40.
The gear case 40 is made of a material having excellent heat dissipation, such as aluminum die-cast. The outer shape of the gear case 40 is formed in a box shape having an opening 40a on one surface. The gear case 40 has a gear accommodating portion 42 for accommodating the worm deceleration mechanism 41 inside. Further, on the side wall 40b of the gear case 40, an opening 43 for passing the through hole 10a of the first motor case 6 and the gear accommodating portion 42 is formed at a position where the first motor case 6 is integrally molded. There is.

Further, a substantially cylindrical bearing boss 49 is provided so as to project from the bottom wall 40c of the gear case 40.
The bearing boss 49 is provided to rotatably support the output shaft 48 of the worm reduction mechanism 41, and is provided with a slide bearing (not shown) on the inner peripheral surface.
Further, an O-ring (not shown) is attached to the inner peripheral edge of the tip of the bearing boss 49. This prevents dust and water from entering from the outside to the inside through the bearing boss 49.
Further, a plurality of ribs 52 are provided on the outer peripheral surface of the bearing boss 49. As a result, the desired rigidity of the bearing boss 49 is secured.

The worm deceleration mechanism 41 housed in the gear accommodating portion 42 is composed of a worm shaft 44 and a worm wheel 45 meshed with the worm shaft 44.
The worm shaft 44 is arranged coaxially with the shaft 31 of the motor unit 2. The worm shaft 44 is rotatably supported at both ends by bearings 46 and 47 provided on the gear case 40. The end of the worm shaft 44 on the motor portion 2 side protrudes through the bearing 46 to the opening 43 of the gear case 40. The end of the protruding worm shaft 44 and the end of the shaft 31 of the motor portion 2 are joined, and the worm shaft 44 and the shaft 31 are integrated. The worm shaft 44 and the shaft 31 may be integrally formed by forming a worm shaft portion and a rotating shaft portion from one base material.

The worm wheel 45 meshed with the worm shaft 44 is provided with an output shaft 48 at the radial center of the worm wheel 45. The output shaft 48 is arranged coaxially with the rotation axis direction of the worm wheel 45, and projects to the outside of the gear case 40 via the bearing boss 49 of the gear case 40. A spline 48a that can be connected to an electrical component (not shown) is formed at the protruding tip of the output shaft 48.

Further, in the radial center of the worm wheel 45, a sensor magnet (not shown) is provided on the side opposite to the side on which the output shaft 48 is projected. This sensor magnet constitutes one of the rotation position detection units 60 that detects the rotation position of the worm wheel 45. The magnetic detection element 61 constituting the other side of the rotation position detection unit 60 is provided on the controller unit 4 arranged to face the worm wheel 45 on the sensor magnet side of the worm wheel 45 (the opening 40a side of the gear case 40). ing.

<Controller part>
The controller unit 4 that controls the drive of the motor unit 2 has a controller board 62 on which the magnetic detection element 61 is mounted, and a cover 63 provided so as to close the opening 40a of the gear case 40. The controller board 62 is arranged to face the sensor magnet side of the worm wheel 45 (the opening 40a side of the gear case 40).

The controller substrate 62 is a so-called epoxy substrate on which a plurality of conductive patterns (not shown) are formed. The terminal portion of the coil 24 drawn out from the stator core 20 of the motor portion 2 is connected to the controller board 62, and the terminal (not shown) of the connector 11 provided on the cover 63 is electrically connected to the controller board 62. Further, in addition to the magnetic detection element 61, a power module (not shown) including a switching element such as a FET (Field Effect Transistor) that controls the current supplied to the coil 24 is mounted on the controller board 62. ing. Further, a capacitor (not shown) for smoothing the voltage applied to the controller board 62 is mounted on the controller board 62.

The cover 63 that covers the controller substrate 62 configured in this way is made of resin. Further, the cover 63 is formed so as to slightly bulge outward. The inner surface side of the cover 63 is a controller accommodating portion 56 that accommodates the controller board 62 and the like.
Further, the connector 11 is integrally molded on the outer peripheral portion of the cover 63. The connector 11 is formed so as to be fitted to a connector extending from an external power source (not shown). The controller board 62 is electrically connected to a terminal (not shown) of the connector 11. As a result, the electric power of the external power source is supplied to the controller board 62.

Further, on the opening edge of the cover 63, a fitting portion 81 to be fitted with the end portion of the side wall 40b of the gear case 40 is formed so as to project. The fitting portion 81 is composed of two walls 81a and 81b along the opening edge of the cover 63. Then, the end portion of the side wall 40b of the gear case 40 is inserted (fitted) between these two walls 81a and 81b. As a result, the labyrinth portion 83 is formed between the gear case 40 and the cover 63. The labyrinth portion 83 prevents dust or water from entering between the gear case 40 and the cover 63. The gear case 40 and the cover 63 are fixed by fastening bolts (not shown).

<Operation of brushless motor wiper motor>
Next, the operation of the brushless wiper motor 1 will be described.
In the brushless wiper motor 1, the electric power supplied to the controller board 62 via the connector 11 is selectively supplied to each coil 24 of the motor unit 2 via a power module (not shown).
Then, the current flowing through each coil 24 forms a predetermined interlinkage magnetic flux in the stator 8 (teeth 22). This interlinkage magnetic flux generates a magnetic attraction force or a repulsive force (magnet torque) with the effective magnetic flux formed by the permanent magnet 33 of the rotor 9.

Further, the salient pole 35 of the rotor core 32 has a protruding direction in which the interlinkage magnetic flux from the stator 8 (teeth 22) easily flows, and the magnetic resistance (relactance) of the magnetic path of the interlinkage magnetic flux is reduced. A reluctance torque that rotates the rotor core 32 is generated.
These magnet torques and reluctance torques continuously rotate the rotor 9.
The rotation of the rotor 9 is transmitted to the worm shaft 44 integrated with the shaft 31, and further transmitted to the worm wheel 45 meshed with the worm shaft 44. Then, the rotation of the worm wheel 45 is transmitted to the output shaft 48 connected to the worm wheel 45, and the output shaft 48 drives a desired electrical component.

Further, the detection signal of the rotation position of the worm wheel 45 detected by the magnetic detection element 61 mounted on the controller board 62 is output to an external device (not shown). An external device (not shown) is a software functional unit that functions by executing a predetermined program by a processor such as a CPU (Central Processing Unit). The software function unit is an ECU (Electronic Control Unit) including a processor such as a CPU, a ROM (Read Only Memory) for storing a program, a RAM (Random Access Memory) for temporarily storing data, and an electronic circuit such as a timer. ..

Further, at least a part of the external device (not shown) may be an integrated circuit such as an LSI (Large Scale Integration). An external device (not shown) controls the switching timing of the switching element of the power module (not shown) based on the rotation position detection signal of the worm wheel 45, and controls the drive of the motor unit 2. The output of the drive signal of the power module and the drive control of the motor unit 2 may be executed by the controller unit 4 instead of an external device (not shown).

<Action of permanent magnet>
Next, the operation of the permanent magnet 33 will be described with reference to FIG.
FIG. 5 is an explanatory diagram showing an example of the flow of the interlinkage magnetic flux to the salient pole 35 of the rotor 9. FIG. 5 corresponds to FIG. 4 described above.
As shown in FIG. 5, when the interlinkage magnetic flux due to the coil 24 of the stator 8 flows from the teeth 22 on the front side in the rotation direction R toward the salient pole 35 during rotation of the rotor 9, the salient pole 35 of the permanent magnet 33 That is, the interlinkage magnetic flux tries to pass in the vicinity of the second region R2 of the permanent magnet 33. That is, the interlinkage magnetic flux tries to enter the second region R2 of the permanent magnet 33. The direction of the flow of the interlinkage magnetic flux near the second region R2 is an oblique direction with respect to the radial direction so as to be directed from the radial outer side of the rotor 9 toward the tip of the salient pole 35 (arrow Y1 in FIG. 5). reference).

Here, in the permanent magnet 33, when the interlinkage magnetic flux flows and the interlinkage magnetic flux penetrates into the permanent magnet 33, a demagnetizing field occurs. The interlinkage magnetic flux tends to flow (easily penetrate) along the magnetization orientation of the permanent magnet 33. However, the magnetization orientation of the second region R2 in the permanent magnet 33 in the vicinity of the salient pole 35 is the radial orientation (arrow RM) with respect to the direction of the flow of the interlinkage magnetic flux toward the salient pole 35 (arrow Y1). Since the radial orientation is along the radial direction, it intersects with the flow of the interlinkage magnetic flux near the second region R2. Therefore, it becomes difficult for the interlinkage magnetic flux to flow (difficult to invade) in the second region R2.

Therefore, according to the rotor 9 of the present embodiment, the chain of the coil 24 of the stator 8 is formed by setting the magnetization orientation of the second region R2, which is both ends in the circumferential direction of the permanent magnet 33 adjacent to the salient pole 35, to the radial orientation. It is possible to suppress the occurrence of demagnetization due to the cross magnetic flux. In other words, the second region R2 is a region in which the interlinkage magnetic flux is easily attracted toward the salient pole 35, that is, a region on the salient pole 35 side centered on the second straight line L2 of the permanent magnet 33. For this reason, it is effective that the interlinkage magnetic flux invades the permanent magnet 33 by positively setting the magnetization orientation that intersects the flow of the interlinkage magnetic flux at the portion of the permanent magnet 33 that is easily affected by the interlinkage magnetic flux. Can be prevented.

FIG. 6 shows a change in the demagnetization rate of the permanent magnet 33 when the vertical axis is the demagnetization rate [%] of the permanent magnet 33 in the second region R2 and the horizontal axis is the current value [A] supplied to the coil 24. It is a graph and is compared by magnetization orientation.
As shown in FIG. 6, when the magnetization orientation of the second region R2 is parallel orientation, or the reverse radial orientation (two points in FIG. 3) so as to be on the outer peripheral surface 33a of the permanent magnet 33 and toward the central portion 33c in the circumferential direction. It can be confirmed that the demagnetization rate is suppressed in the case of radial orientation as compared with the case of (see the arrow indicated by the chain line).

Further, according to the rotor 9 of the present embodiment, since the magnetization orientation of the first region R1 of the permanent magnet 33 is parallel orientation, the motor characteristics of the brushless wiper motor 1 can be improved. It will be described in detail below.

FIG. 7 is a graph comparing the case where the vertical axis is the effective magnetic flux [μWb] of the permanent magnet 33 and the magnetization orientation of the permanent magnet 33 is the parallel orientation and the radial orientation.
As shown in FIG. 7, it can be confirmed that when the magnetization orientation of the permanent magnet 33 is parallel orientation, the effective magnetic flux is increased as compared with the case of radial orientation. Therefore, by setting the magnetization orientation of the first region R1 which is not easily affected by the interlinkage magnetic flux at a position away from the salient pole 35 to the parallel orientation, the effective magnetic flux of the permanent magnet 33 at the time of driving the brushless wiper motor 1 is sufficient. It will be possible to secure it. Therefore, the motor characteristics of the brushless wiper motor 1 can be improved.

Further, since the magnetization orientation of the second region R2 is only changed with respect to the magnetization direction of the first region R1, there is no need to change the material between the first region R1 and the second region R2 of the permanent magnet 33, for example. .. Therefore, the permanent magnet 33 can be easily manufactured, and an increase in manufacturing cost can be suppressed.
By making the entire second region R2 radially oriented, demagnetization of the entire second region R2 can be suppressed.

The present invention is not limited to the above-described embodiment, and includes various modifications to the above-mentioned embodiment without departing from the spirit of the present invention.
For example, in the above-described embodiment, the brushless wiper motor 1 is taken as an example of the motor, but the motor according to the present invention is not limited to the brushless wiper motor 1. For example, the motor may be a drive source for various electrical components mounted on the vehicle (for example, a power window, a sunroof, an electric seat, etc.) or a drive source mounted on various devices other than the vehicle.

In the above-described embodiment, in the rotor core 32, the arc center Co of the outer peripheral surface 33a is eccentric with respect to the axial center C1 of the shaft 31, but the present invention is not limited to this.
For example, in the permanent magnet 33, the arc center Co of the outer peripheral surface 33a on the outer peripheral surface in the radial direction may coincide with the axial center C1 of the shaft 31. In this case, the permanent magnet 33 has a uniform radial thickness between the outer peripheral surface 33a and the inner peripheral surface 33b over the entire circumferential direction. Along with this, the gap between the outer peripheral surface 33a on the radial outer side of the permanent magnet 33 and the inner peripheral surface of the teeth 22 becomes constant over the entire circumferential direction.

In the above-described embodiment, the concave portion 38 is formed on the tip surface 35a of the salient pole 35, but the present invention is not limited to this, and the concave portion 38 may be omitted.

In the above-described embodiment, the case where the permanent magnet 33 has a parallel orientation in which the entire magnetization orientation of the first region R1 is parallel to the first straight line L1 has been described. However, it is not limited to this. Instead of parallel orientation, the magnetization orientation of the first region R1 is radial orientation along the radial direction, reverse radial orientation toward the circumferential central portion 33c on the outer peripheral surface 33a of the permanent magnet 33, and polar anisotropy. Various magnetization orientations such as orientation can be adopted. The entire first region R1 does not have to have the same magnetization orientation.

In the above-described embodiment, the case where the permanent magnet 33 has a radial orientation in which the entire magnetization orientation of the second region R2 is in the radial direction has been described. However, the present invention is not limited to this, and at least a part of the second region R2 may be radial oriented. The parts other than the radial orientation of the second region R2 may be the same as the orientation of the first region R1. However, when only a part of the second region R2 is radially oriented, there is a possibility that the entire second region R2 is demagnetized slightly as compared with the case where the entire second region R2 is radially oriented.

1 ... Brushless wiper motor, 2 ... Motor unit (motor), 3 ... Deceleration unit, 4 ... Controller unit, 5 ... Motor case, 6 ... First motor case, 6a, 7a ... Opening, 7 ... Second motor case, 8 ... stator, 9 ... rotor, 10 ... bottom, 10a ... through hole, 11 ... connector, 16 ... outer flange part, 17 ... outer flange part, 19 ... slot, 20 ... stator core, 21 ... core part, 22 ... teeth, 22a ... Teeth body, 22b ... Collar, 23 ... Insulator, 24 ... Coil, 31 ... Shaft, 32 ... Rotor core, 32a ... Through hole, 32b ... Outer surface, 32c ... Round chamfer, 33 ... Permanent magnet (magnet), 33a ... outer peripheral surface, 33b ... inner peripheral surface, 33c ... circumferential central portion, 33d ... circumferential side surface, 33f ... arc surface, 33s ... end portion, 35 ... salient pole, 35a ... tip surface, 35b ... round chamfering portion, 35c ... side, 36 ... magnet storage, 38 ... recess, 40 ... gear case, 40a, 43 ... opening, 40b ... side wall, 40c ... bottom wall, 41 ... worm deceleration mechanism, 42 ... gear housing, 44 ... worm Shaft, 45 ... worm wheel, 46, 47 ... bearing, 48 ... output shaft, 48a ... spline, 49 ... bearing boss, 52 ... rib, 56 ... controller housing, 60 ... rotation position detector, 61 ... magnetic detection element, 62 ... Controller board, 63 ... Cover, 70 ... Magnet cover, 81 ... Fitting part, 81a ... Wall, 81b ... Wall, 83 ... Labyrinth part, C1 ... Axis center (rotation axis), C2 ... Intersection point, L1 ... First Straight line, L2 ... 2nd straight line, Lh ... Complementary straight line, Lk ... Curve, R1 ... 1st region, R2 ... 2nd region, PM ... Parallel orientation, RM ... Radial orientation

Claims (5)

A shaft that rotates around the axis of rotation and
A rotor core that holds the shaft and rotates about the axis of rotation in the radial direction.
A plurality of magnets arranged side by side along the circumferential direction on the outer peripheral surface of the rotor core, and
A salient pole protruding outward in the radial direction of the rotor core between the magnets adjacent to each other in the circumferential direction of the outer peripheral surface of the rotor core.
Equipped with
The plurality of the magnets are parallel to the first straight line passing through the circumferential center of the magnet and the rotational axis when viewed from the rotational axis direction, and are a straight line along the circumferential side surface of the salient pole and the outer peripheral surface of the rotor core. It has a first region on the central side in the circumferential direction and a second region on the salient pole side with a second straight line passing through an intersection with a curve along the same direction.
The rotor is characterized in that the magnetization orientation of at least a part of the second region is a radial orientation along the radial direction. The rotor according to claim 1, wherein the entire magnetization orientation of the second region is a radial orientation. The rotor according to claim 1 or 2, wherein the magnetization orientation of the first region is a parallel orientation in a direction parallel to the first straight line. An annular stator core and a stator having a plurality of teeth protruding inward in the radial direction from the inner peripheral surface of the stator core,
The coil attached to the tooth and
The rotor according to any one of claims 1 to 3, which is arranged inside the plurality of teeth in the radial direction.
A motor characterized by being equipped with. A brushless wiper motor comprising the motor according to claim 4 as a drive source for a wiper mounted on a vehicle.

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