JP7080704B2 - Rotor, motor and brushless wiper motor - Google Patents

Description

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

Conventionally, a brushless wiper motor has been applied for driving a wiper of a vehicle.
This type of motor comprises a stator having a tooth around which a coil is wound and a rotor rotatably provided inside the stator in the radial direction. The rotor has a shaft, a substantially cylindrical rotor core that is fitted and fixed to the shaft, and a magnet provided on the rotor core. Then, a magnetic attraction force or a repulsive force is generated between the interlinkage magnetic flux formed on the stator and the magnet provided on the rotor core, and the rotor continuously rotates.

Here, as one of the methods of arranging the magnet on the rotor, there is an SPM (Surface Permanent Magnet) type in which the magnet is attached to the outer peripheral surface of the rotor core. In this type of SPM type motor, the rotor core is provided with a magnet cover that covers the entire outer surface of the magnet. The magnet cover holds the magnet on the outer peripheral surface of the rotor core.

The magnet cover is fixed to the rotor core and the magnet by, for example, a press-fitting method or an adhesive method using an adhesive.

Here, Patent Document 1 describes a configuration in which uneven portions are provided on the opposite surfaces of the end face of the rotor core and the magnet cover, and the magnet cover is fixed by abutting them with each other. As a result, compared to press-fitting and bonding, it is possible to reliably secure the fixing strength without damaging the magnet and under efficient work.

Japanese Unexamined Patent Publication No. 2008-295140

However, in the technique described in Patent Document 1, since a force is applied to the magnet when crimping at the mating portion, the magnet cracks due to contact with the magnet cover, especially at the corner portion of the magnet where stress tends to concentrate. There was a problem that it would end up.

Therefore, the present invention provides a rotor, a motor, and a brushless wiper motor that can improve the mounting work efficiency of the magnet cover and reduce the cracking of the magnet.

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 rotates about the axis of rotation in the radial direction, and a magnet arranged on the outer peripheral surface of the rotor core. The rotor core is provided with a rotor core and a magnet cover for covering the magnet, and the rotor core is provided between a cylindrical portion having a shaft holding hole for holding the shaft and the magnets adjacent to each other in the circumferential direction of the outer peripheral surface of the cylindrical portion. The magnet cover comprises a salient pole formed so as to project outward in the radial direction, and the magnet cover includes an end face cover covering the magnet, the rotor core, and the one end surface side of the salient pole in the rotation axis direction, and the end face. It extends from the outer peripheral edge of the cover along the rotation axis direction through a bent portion formed at a position corresponding to the corner portion of the magnet and the corner portion of the salient pole, and covers the outer periphery of the magnet and the salient pole. An outer peripheral surface cover is provided, and an engaging portion for engaging the rotor core and the magnet cover so as not to rotate relative to each other is provided on the one end surface in the rotation axis direction of the rotor core and the end surface cover. At least one of the corner portion and the bent portion is provided with an avoidance portion for avoiding contact with the other, and the engaging portion is provided on one end surface of the cylindrical portion in the direction of the rotation axis. It is characterized by comprising an engaging hole formed and an engaging claw formed on the end face cover and capable of engaging with the engaging hole .

With such a configuration, it is possible to improve the mounting work efficiency of the magnet cover and prevent the corners of the magnet, where stress is easily concentrated during mounting, from coming into contact with the magnet cover. Therefore, it is possible to reduce the cracking of the magnet as compared with the conventional technique.
Further, the rotor core and the magnet cover can be engaged with each other with a simple structure.
Further, when the rotor rotates, it is crimped at a position coaxial with the direction in which the largest centrifugal force of the magnet acts, thereby suppressing the magnet cover from swelling in the radial direction. Therefore, the gap between the stator and the rotor can be kept constant, and a high-performance rotor can be obtained.

In the rotor according to the present invention, an inclined surface is formed at the corner portion corresponding to the bent portion of the magnet so that the thickness in the radial direction becomes thinner toward one end side in the rotation axis direction. It is characterized in that the inclined surface is used as the avoidance portion.

With this configuration, contact between the corners of the magnet and the magnet cover is avoided with a simple structure. In addition, by making the corners a surface, it is possible to make the shape so that stress concentration is difficult and to increase the strength of the magnet. Therefore, the cracking of the magnet can be further reduced.

The rotor according to the present invention is characterized in that the angle of the inclined surface is 20 ° to 30 ° with respect to the rotation axis.

By loosening the tilt angle of the tilted surface in this way, the magnet cover can be easily inserted smoothly from one end side in the direction of the rotation axis. Therefore, the assembling property of the magnet cover can be improved.

In the rotor according to the present invention, the bent portion has an overhanging portion extending over the entire circumference on the outer side in the direction of the rotation axis, and the overhanging portion is used as the avoiding portion.

With such a configuration, the distance between the corner portion of the magnet and the magnet cover becomes long, and the contact between the corner portion and the magnet cover can be easily avoided. Therefore, the cracking of the magnet can be further reduced.

In the rotor according to the present invention, the magnet is characterized in that the radial thickness at the circumferential end portion is smaller than the radial thickness at the circumferential intermediate portion.

Here, since the salient poles protrude from both ends in the circumferential direction of the magnet, it is easy to avoid contact between the corners of the magnet and the magnet cover. On the other hand, the circumferential middle portion of the magnet is easily in contact with the magnet cover because it is separated from the salient pole. By making the radial middle portion of the magnet that is easily in contact thicker than both peripheral ends, the strength of the circumferential middle portion of the magnet can be increased more than that of both peripheral ends. By bringing such a circumferential middle portion of the magnet into contact with the magnet cover, the radial movement of the magnet is fixed. Therefore, the magnet cover can be securely fixed and the cracking of the magnet can be reduced.
Further, the thickness in the radial direction of the magnet becomes thinner toward both ends in the circumferential direction, and the distance from the stator becomes longer toward both ends in the circumferential direction of the magnet. Therefore, it is possible to suppress a sudden change in magnetic flux with respect to the stator between magnets adjacent to each other in the circumferential direction. Therefore, the cogging torque can be reduced.

The rotor according to the present invention is characterized in that the engaging hole is formed in the circumferential intermediate portion of the salient poles adjacent to each other in the circumferential direction in the cylindrical portion .

In this way, by forming an engaging hole in the circumferential middle portion of the magnet in the rotor core, it is possible to prevent the engaging hole from obstructing the magnetic path of the magnet as much as possible. Therefore, it is possible to obtain a rotor with higher performance.

The rotor according to the present invention is characterized in that the engaging hole communicates with the shaft holding hole in the radial direction.

With this configuration, the weight of the rotor core can be reduced and the inertia can be improved, and a high-performance rotor can be obtained. Further, since the contact area with the rotor core is reduced when the shaft is press-fitted, the press-fitting load of the shaft can be reduced and workability can be improved.

The motor according to the present invention includes an annular stator core and a stator having a plurality of teeth protruding radially inward from the inner peripheral surface of the stator core, and the above-mentioned one is described on the radial inside of the teeth. It is characterized by having a rotor.

With such a configuration, it is possible to provide a motor capable of improving the mounting work efficiency of the magnet cover and reducing the cracking of the magnet.

Further, the brushless wiper motor according to the invention of claim 9 is characterized in that the above-mentioned motor is provided for driving a wiper of a vehicle.

With such a configuration, it is possible to provide a brushless wiper motor capable of improving the mounting work efficiency of the magnet cover and reducing the cracking of the magnet.

According to the present invention, the mounting work efficiency of the magnet cover is improved as compared with the conventional technique, and the corners of the magnet where stress tends to be concentrated during mounting are prevented from coming into contact with the magnet cover. Cracks can be reduced.

It is a perspective view of the wiper device which concerns on 1st Embodiment. It is sectional drawing of the motor which concerns on 1st Embodiment. It is a top view of the rotor which concerns on 1st Embodiment. It is a bottom view of the rotor which concerns on 1st Embodiment. It is an exploded perspective view of the rotor which concerns on 1st Embodiment. It is sectional drawing which follows AA of FIG. It is a partially enlarged view at the magnet corner part of FIG. FIG. 3 is a partially enlarged view of a magnet corner portion in a cross-sectional view taken along the line BB of FIG. It is a magnetic circuit contour figure of a motor at the time of energization. It is a perspective view of the rotor core which concerns on 1st modification. It is a perspective view of the rotor core which concerns on the 2nd modification. It is a partial cross-sectional enlarged view in the magnet corner part which concerns on 2nd Embodiment. It is a perspective view of the rotor core which concerns on 3rd Embodiment.

Next, an embodiment of the present invention will be described with reference to the drawings.

(First Embodiment)
(Wiper device)
1 to 9 are drawings showing a wiper device, a motor, and a rotor according to the first embodiment.
As shown in FIG. 1, the wiper device 11 is provided on the window glass (not shown) of the vehicle, and wipes off rain, dirt, and the like adhering to the window glass to secure the driver's field of vision.
The wiper device 11 includes, for example, two wiper arms 13 provided on the driver's seat side and the passenger's seat side, a wiper blade 14 attached to the tip of each wiper arm 13, a wiper shaft 15, and a link mechanism 16. And a brushless wiper motor (motor) 1.

The base end of each wiper arm 13 is fixed to the wiper shaft 15. The wiper shaft 15 is rotatably supported by the vehicle around its central axis. Each wiper shaft 15 is connected to a motor 1 fixed to the vehicle via a link mechanism 16. When the motor 1 operates, the two wiper shafts 15 and 15 rotate in synchronization with each other. The wiper arm 13 swings in a predetermined range integrally with the wiper shaft 15.

(Brushless wiper motor) (Motor)
FIG. 2 is a cross-sectional view of the motor according to the first embodiment.
The motor 1 is, for example, a drive source for electrical components mounted on a vehicle (for example, the wiper device described above). The motor 1 includes a motor unit 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 axial direction of the rotating shaft (shaft 31) of the motor unit 2, and the term "circumferential direction" refers to the circumferential direction of the shaft 31. Refers to the radial direction of the shaft 31.

(Motor section)
The motor unit 2 is provided in the motor case 5, the annular stator 6 housed in the motor case 5, and the rotor 7 rotatably provided inside the stator 6 in the radial direction. And have. The motor unit 2 is a so-called brushless motor that does not require a brush to supply electric power to the stator 6.

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 52 and a second motor case 53, which are configured to be rotatable in the axial direction. The first motor case 52 and the second motor case 53 are each formed in a bottomed cylindrical shape.
The first motor case 52 covers the motor portion 2 from one end side in the axial direction. The first motor case 52 extends outward in the radial direction over the entire circumferential direction of the one end side bottom portion 52a on the one end side in the axial direction, the one end side opening 52b on the other end side in the axial direction, and the one end side opening 52b. It has one end side edge portion 52c and a protrusion. A bolt hole (not shown) penetrating in the axial direction is formed in the one end side edge portion 52c.

The second motor case 53 covers the motor portion 2 from the other end side in the axial direction. The second motor case 53 has a bottom portion 53a on the other end side on the other end side in the axial direction, an opening 53b on the other end side on one end side in the axial direction, and an opening portion 53b on the other end side in the radial direction. It has an other end side edge portion 53c extending toward it. The second motor case 53 is integrally molded with the gear case 55 so that the bottom portion 53a on the other end side is joined to the gear case 55 of the deceleration portion 3. A bolt hole (not shown) penetrating in the axial direction is formed in the other end side edge portion 53c. A through hole 53d through which the shaft 31 of the rotor 7 can be inserted is formed at substantially the center of the bottom portion 53a on the other end side in the radial direction.

The one end side edge portion 52c of the first motor case 52 and the other end side edge portion 53c of the second motor case 53 are in contact with each other from the axial direction. Further, the bolt holes formed in the one end side edge portion 52c and the other end side edge portion 53c are formed so as to be coaxial when the one end side edge portion 52c and the other end side edge portion 53c are in contact with each other. .. A bolt 17 is inserted into the bolt hole. As a result, the one end side edge portion 52c and the other end side edge portion 53c are combined to form a motor case 5 having an internal space. Then, in the internal space of the motor case 5, the stator 6 is arranged so as to be fitted inside the first motor case 52 and the second motor case 53.

(Stator)
The stator 6 includes a stator core 61 in which a cylindrical core portion 63 arranged coaxially with the shaft 31 and a plurality of teeth 64 protruding inward in the radial direction from the core portion 63 are integrally formed, and the stator core 61. It includes a plurality of teeth 64 protruding radially inward from the peripheral surface, and a coil 69 mounted on the teeth 64. The stator 6 is fixed to the inner peripheral surface of the motor case 5 and causes a rotating magnetic field to act on the rotor 7.
The stator core 61 is configured by laminating electromagnetic steel sheets in the axial direction. The stator core 61 may be a so-called dust core.

The teeth 64 includes a teeth body 65 (see FIG. 9) protruding radially inward from the inner peripheral surface of the core portion 63, and a flange portion 66 extending in the circumferential direction from the radial inner end of the teeth body 65. Is integrally molded. A slot 67 is formed between the flange portions 66 adjacent to each other in the circumferential direction.

Further, as shown in FIG. 2, the inner peripheral surface of the core portion 63 and the teeth 64 are covered with the insulator 23 made of resin. A coil 69 is wound around each tooth 64 from above the insulator 23. Each coil 69 generates a magnetic field for rotating the rotor 7 by feeding power from the controller unit 4.

(Rotor)
The rotor 7 is rotatably provided inside the stator 6 via a minute gap. The rotor 7 is arranged on a shaft 31 that rotates around a rotation axis (axis C), a columnar rotor core 71 that rotates integrally with the shaft 31 with the axis C as the radial center, and an outer peripheral surface of the rotor core 71. It includes a plurality of magnets 72 (four in the first embodiment), and a magnet cover 73 that covers the rotor core 71 and the magnet 72 from the outside in the axial direction and the radial direction. The shaft 31 is integrally molded with the worm shaft 43 constituting the deceleration unit 3, which will be described later.

FIG. 3 is a top view of the rotor, and FIG. 4 is a bottom view of the rotor. FIG. 5 is an exploded perspective view of the rotor.
The rotor core 71 is configured by laminating a plurality of metal plates in the axial direction. The rotor core 71 may be a so-called dust core.
As shown in FIGS. 3 to 5, the rotor core 71 is formed on a cylindrical cylindrical portion 75 having a shaft holding hole 78 in the radial center and an outer peripheral surface of the cylindrical portion 75 so as to project outward in the radial direction. The salient pole 76 and the salient pole 76 are integrally formed. The shaft 31 is press-fitted and fixed in the shaft holding hole 78. The shaft 31 may be inserted into the shaft holding hole 78, and the rotor core 71 may be externally fitted and fixed to the shaft 31 using an adhesive or the like.

Four engaging holes 79 are formed at one end of the cylindrical portion 75 in the axial direction at equal intervals in the circumferential direction. The engagement hole 79 is for fixing the magnet cover 73 to the rotor core 71. The engagement hole 79 is formed in an arc shape in which the inner side in the radial direction is shorter than the outer side in the radial direction when viewed from the axial direction. The engagement hole 79 penetrates in the axial direction in parallel with the shaft core C. The engaging hole 79 may be a recessed portion that does not penetrate in the axial direction. That is, it may be a recessed portion provided on the axial end surface of the rotor core 71 and having a depth sufficient to engage the engaging claw 95 described later.

A plurality of salient poles 76 (four in the present embodiment) are formed at equal intervals in the circumferential direction so as to be located between the engaging holes 79 adjacent to each other in the circumferential direction. Each salient pole 76 is formed so as to extend in the entire axial direction of the rotor core 71. Further, a U-shaped groove 77 is formed at the radial outer tip of the salient pole 76 over the entire axial direction.
On the outer peripheral surface of the cylindrical portion 75 formed in this way, magnets 72 are arranged between two salient poles 76 adjacent to each other in the circumferential direction. In other words, the salient pole 76 is arranged between the magnets 72 adjacent to each other in the circumferential direction. The magnet 72 is fixed to the rotor core 71 with, for example, an adhesive.

The magnet 72 extends between the salient poles 76 of the rotor core 71 in parallel with the axial direction. A plurality of magnets 72 are arranged so that the magnetic flux lines 80 (see FIG. 9) are arranged radially outward and radially inward alternately.
The magnet 72 is formed in a substantially arc shape when viewed from the axial direction. In a plan view seen from the axial direction, the outer surface 81 on the outer side in the radial direction and the inner surface 82 on the inner side in the radial direction of the magnet 72 are each formed in an arc shape whose arc center is coaxial with the axis C of the shaft 31. The inner surface 82 is adhered to the outer peripheral surface of the cylindrical portion 75 of the rotor core 71. Further, in a plan view seen from the axial direction, the side surfaces 83 at both ends in the circumferential direction of the magnet 72 are formed in parallel with the wall surface 76a of the salient pole 76 with which the side surfaces 83 face each other. The side surface 83 is in contact with the wall surface 76a of the salient pole 76.

The arc center C1 (not shown) of the outer surface 81 of the magnet 72 may be eccentric from the axis C of the shaft 31. Specifically, the arc center C1 of the outer surface 81 of the magnet 72 is on a straight line L1 (not shown) along the radial direction passing through the center between two salient poles 76 adjacent to each other in the circumferential direction of the rotor core 71 and on the axis. It may be set closer to the outer peripheral surface of the corresponding rotor core 71 than the core C. At this time, the thickness of the magnet 72 in the radial direction at the peripheral end portion is smaller than the radial thickness in the circumferential intermediate portion.
That is, the gap between the outer surface 81 of the magnet 72 and the inner peripheral surface of the teeth 64 is the smallest at the center of the circumferential direction of the magnet 72, and the gap gradually increases as the distance from the center of the circumferential direction increases in the circumferential direction. It may be configured in.

Further, inclined surfaces 85 are formed at both ends in the axial direction of the magnet 72 and at the corners on the outer side in the radial direction. The inclined surface 85 is formed so that the thickness in the radial direction becomes thinner toward one end side (first side) in the axial direction. Further, the inclined surface 85 is similarly formed on the other end side (second side) of the magnet 72 in the axial direction. The inclined surface 85 on the second side in the axial direction is formed so that the thickness in the radial direction becomes thinner toward the other end side (second side) in the axial direction. The angle of the inclined surface 85 is 20 ° to 30 ° with respect to the axis.
In the first embodiment, the inclined surface 85 functions as an avoidance portion. By forming the inclined surface 85, the bent portions 92 and 97 of the magnet cover 73 are in contact with the salient pole 76 of the rotor core 71 only on the inside thereof.

(Magnet cover)
6 is a cross-sectional view taken along the line AA of FIG. 3, and FIG. 7 is a partially enlarged view of a magnet corner portion of FIG. Further, FIG. 8 is a partially enlarged view of a magnet corner portion in a cross-sectional view taken along the line BB of FIG.
The magnet cover 73 is a hollow columnar shape that covers the magnet 72 and the rotor core 71 from the end face and the outer side of the peripheral surface. As shown in FIGS. 5 and 6, the magnet cover 73 includes an end face cover (first end face cover 91 and second end face cover 98) that covers the axial end faces of the magnet 72, the rotor core 71, and the salient pole 76, and the end face cover. Bent portions (first bent portion 92 and second bent portion 97) formed at positions corresponding to the corners of the magnet 72 and the corners 76b of the salient pole 76 from the outer peripheral edge, and along the axial direction via the bent portions. An outer peripheral surface cover 93 that extends and covers the outer periphery of the magnet 72 and the salient pole 76 is integrally formed.

The first end face cover 91 is in contact with the end faces of the rotor core 71 and the magnet 72 from one end side in the axial direction. A circular shaft through hole 94 through which the shaft 31 penetrates is provided in the central portion of the first end surface cover 91. The inner diameter of the shaft through hole 94 is larger than the outer diameter of the shaft 31 and smaller than the outer diameter of the cylindrical portion 75 of the rotor core 71. The shaft through hole 94 may have a shape other than a circular shape, such as a square shape.

Further, four engaging claws 95 are formed on the inner peripheral edge of the shaft through hole 94 at equal intervals in the circumferential direction. The engaging claw 95 is formed at a position corresponding to the engaging hole 79 of the rotor core 71. Here, the engaging claw 95 exists on the same plane as the first end surface cover 91 before being engaged with the engaging hole 79, and can be bent by about 90 ° inside the magnet cover 73. When the engaging claw 95 is engaged with the engaging hole 79, the magnet cover 73 cannot rotate with respect to the rotor core 71. That is, the engaging hole 79 and the engaging claw 95 function as an engaging portion that engages the rotor core 71 and the magnet cover 73 so as not to rotate relative to each other.

The second end face cover 98 is in contact with the end faces of the rotor core 71 and the magnet 72 from the other end side in the axial direction. The first end face cover 91 and the second end face cover 98 restrict the axial movement of the magnet 72 with respect to the rotor core 71.
The second end face cover 98 is provided with a cover opening 96 at the center thereof. The inner diameter of the cover opening 96 is larger than the shaft through hole 94 and smaller than the outer surface 81 of the magnet 72.

The outer peripheral surface cover 93 is in contact with the outer surface 81 of the magnet 72 from the outside in the radial direction.

The first bent portion 92 is located between the first end surface cover 91 and the outer peripheral surface cover 93. The second bent portion 97 is located between the second end surface cover 98 and the outer peripheral surface cover 93. Further, as shown in FIG. 8, the first bent portion 92 and the second bent portion 97 are in contact with the corner portion 76b of the salient pole 76 on the inner side, respectively.

(Deceleration part)
Returning to FIG. 2, the deceleration unit 3 includes a gear case 55 to which the motor case 5 is attached, and a worm deceleration mechanism 41 housed in the gear case 55. The gear case 55 is made of a material having excellent heat dissipation such as aluminum die-cast. The gear case 55 is formed in a box shape having a side opening 55a on one surface, and has a gear accommodating portion 45 for accommodating the worm deceleration mechanism 41 inside. Further, on the side wall 55b of the gear case 55, an opening 56 for communicating the through hole 53d of the second motor case 53 and the gear accommodating portion 45 is formed at a position where the second motor case 53 is integrally formed. There is.

Further, a substantially cylindrical bearing boss 49 is provided so as to project from the bottom wall 55c of the gear case 55. The bearing boss 49 is for rotatably supporting 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 47 are provided on the outer peripheral surface of the bearing boss 49. As a result, the rigidity of the bearing boss 49 is ensured.

The worm reduction mechanism 41 housed in the gear accommodating portion 45 is composed of a worm shaft 43 and a worm wheel 42 meshed with the worm shaft 43. The worm shaft 43 is arranged coaxially with the shaft 31 of the motor unit 2. The worm shaft 43 is rotatably supported at both ends by bearings 38 and 39 provided on the gear case 55. The first side end of the worm shaft 43 projects through the bearing 38 to the opening 56 of the gear case 55. The end of the protruding worm shaft 43 and the end of the shaft 31 of the motor portion 2 are joined, and the worm shaft 43 and the shaft 31 are integrated. The worm shaft 43 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 42 meshed with the worm shaft 43 is provided with an output shaft 48 at the radial center of the worm wheel 42. The output shaft 48 is arranged coaxially with the rotation axis direction of the worm wheel 42, and projects to the outside of the gear case 55 via the bearing boss 49 of the gear case 55. 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 42, 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 50 that detects the rotation position of the worm wheel 42. The magnetic detection element 51 constituting the other side of the rotation position detection unit 50 is provided on the controller unit 4 which is arranged to face the worm wheel 42 on the sensor magnet side of the worm wheel 42 (the side opening 55a side of the gear case 55). ing.

(Controller part)
The controller unit 4 that controls the drive of the motor unit 2 has a controller board 25 on which the magnetic detection element 51 is mounted, and a cover 26 provided so as to close the side opening 55a of the gear case 55. .. The controller board 25 is arranged to face the sensor magnet side of the worm wheel 42 (the side opening 55a side of the gear case 55).

The controller substrate 25 is a so-called epoxy substrate on which a plurality of conductive patterns (not shown) are formed. The terminal portion of the coil 69 drawn out from the stator core 61 of the motor portion 2 is connected to the controller board 25, and the terminal of the connector provided on the cover 26 (all not shown) is electrically connected to the controller board 25. There is. Further, in addition to the magnetic detection element 51, a power module (not shown) including a switching element such as a FET (Field Effect Transistor) that controls the current supplied to the coil 69 is mounted on the controller substrate 25. ing. Further, a capacitor (not shown) for smoothing the voltage applied to the controller board 25 is mounted on the controller board 25.

The cover 26 that covers the controller substrate 25 configured in this way is made of resin. Further, the cover 26 is formed so as to bulge slightly outward. The inner surface side of the cover 26 is a controller accommodating portion 27 accommodating the controller board 25 and the like.
Further, a connector (not shown) is integrally molded on the outer peripheral portion of the cover 26. This connector is formed so as to be fitted to a connector extending from an external power supply (not shown). The controller board 25 is electrically connected to the terminals of the connector (not shown). As a result, the electric power of the external power source is supplied to the controller board 25.

Further, on the opening edge of the cover 26, a fitting portion 28 to be fitted with the end portion of the side wall 55b of the gear case 55 is formed so as to project. The fitting portion 28 is composed of two walls 28a and 28b along the opening edge of the cover 26. Then, the end portion of the side wall 55b of the gear case 55 is inserted (fitted) between these two walls 28a and 28b. As a result, the labyrinth portion 29 is formed between the gear case 55 and the cover 26. The labyrinth portion 29 prevents dust and water from entering between the gear case 55 and the cover 26. The gear case 55 and the cover 26 are fixed by fastening bolts (not shown).

(Motor operation)
Next, the operation of the motor 1 will be described.
In the motor 1, the electric power supplied to the controller board 25 via a connector (not shown) is selectively supplied to each coil 69 of the motor unit 2 via a power module (not shown). Then, a predetermined interlinkage magnetic flux is formed in the stator 6 (teeth 64), and a magnetic attraction force or a repulsive force is generated between the interlinkage magnetic flux and the effective magnetic flux formed by the magnet 72 of the rotor 7. As a result, the rotor 7 continuously rotates.
When the rotor 7 rotates, the worm shaft 43 integrated with the shaft 31 rotates, and further, the worm wheel 42 meshed with the worm shaft 43 rotates. Then, the output shaft 48 connected to the worm wheel 42 rotates, and a desired electrical component is driven.

Further, the rotation position detection result of the worm wheel 42 detected by the magnetic detection element 51 mounted on the controller board 25 is output as a signal to an external device (not shown). In the external device (not shown), the switching timing of the switching element of the power module (not shown) is controlled based on the rotation position detection signal of the worm wheel 42, and the drive control of the motor unit 2 is performed. The output of the drive signal of the power module and the drive control of the motor unit 2 may be performed by the controller unit 4.

(Rotor action and effect)
Next, the operation and effect of the rotor 7 will be described with reference to FIGS. 3 to 9.
When assembling the rotor 7, the magnet 72 is first fixed to the rotor core 71 by adhesion or the like. At this time, a plurality of magnets 72 are arranged between the salient poles 76 of the rotor core 71 so that the outward and inward directions of the magnetic flux lines 80 are alternately arranged in the circumferential direction. Further, the heights of the rotor core 71 and the magnet 72 in the axial direction are the same, and both ends are arranged so as to be flush with each other.

(Action and effect of engaging part)
Here, in the state before the magnet cover 73 is mounted on the rotor core 71 and the magnet 72 (before mounting), the magnet cover 73 includes the first end face cover 91, the first bent portion 92, and the outer peripheral surface cover 93. The second side in the axial direction is open. That is, the second bent portion 97 and the second end face cover 98 have not yet been formed at this point. Further, the engaging claw 95 formed on the edge of the shaft through hole 94 of the first end face cover 91 exists on the same plane as the first end face cover 91 before mounting, and protrudes inward in the radial direction. There is.

Next, a process (at the time of mounting) of mounting the magnet cover 73 will be described.
The magnet cover 73 covers the rotor core 71 and the magnet 72 from the first side in the axial direction with the opening side on the second side in the axial direction facing the rotor core 71. Then, the rotor core 71 and the magnet 72 are housed inside the magnet cover 73. The second bent portion 97 and the second end face cover 98 are simultaneously formed on the magnet cover 73 by crimping or the like in a state where the inner surface of the first end face cover 91 of the magnet cover 73 and the first side end face in the axial direction of the rotor core 71 are in contact with each other. Will be done.
Further, at the same time as the step of forming the second end face cover 98, the engaging claw 95 of the first end face cover 91 is bent by about 90 ° inside the magnet cover 73. Then, the engaging claw 95 is engaged with the engaging hole 79 of the rotor core 71. As a result, the movement of the magnet cover 73 with respect to the rotor core 71 in the circumferential direction (rotational direction) and in the axial direction is restricted. With such a configuration, the rotor core 71 and the magnet cover 73 can be engaged with each other with a simple structure, and the mounting work efficiency of the magnet cover 73 can be improved.

Further, the engaging hole 79 of the rotor core 71 is formed at a position in the circumferential direction so as to overlap with the circumferential intermediate portion of each magnet in the radial direction.
Here, as shown in FIG. 9, the magnetic flux flowing through the rotor core 71 when energized is the largest in the iron pole portion 87 located in the radial middle of the salient pole 76, and the circumferential middle portion of each magnet 72 in the cylindrical portion 75. It is the least at the position corresponding to (rear portion 88). Therefore, in the circumferential direction, the engagement hole 79 is formed at a position (a position corresponding to the back surface portion 88) that overlaps with the circumferential intermediate portion of each magnet in the radial direction, so that the engagement hole forms the magnetic path of the magnet. You can prevent it from being disturbed as much as possible. Therefore, a high-performance rotor can be obtained.
Further, in the present embodiment, when the rotor 7 is rotated, a centrifugal force in the radial direction acts on the circumferential intermediate portion of each magnet 72. Therefore, by forming the engaging hole 79 in the back surface portion 88, when the rotor 7 rotates, the magnet 72 is crimped at a position coaxial with the direction in which the largest centrifugal force acts, and the magnet cover 73 is radially. It can suppress swelling. Therefore, the gap between the stator 6 and the rotor 7 can be kept constant to obtain a high-performance rotor 7.

(Action and effect of avoidance part)
Next, the action and effect of the avoidance portion will be described.
In the present embodiment, the inclined surface 85 of the magnet 72 is used as an avoidance portion.
Here, when the magnet cover 73 is attached, in the crimping step when forming the second bent portion 97 and the second end face cover 98, and in the bending step of bending the engaging claw 95, the magnet cover 73 is provided with the radial direction and the axial direction. Force works inward. At this time, since the magnet cover 73 comes into contact with the magnet 72, stress is generated in the magnet 72. In particular, stress tends to concentrate on the corners of the magnet 72, and cracks may occur from the corners of the magnet 72. In the present embodiment, by forming the inclined surface 85 at the corner portion of the magnet 72, contact between the corner portion of the magnet 72 and the magnet cover 73 is avoided with a simple structure. Therefore, it is possible to suppress the generation of stress at the corners of the magnet 72 of the magnet cover 73 at the time of crimping, and to suppress the cracking of the magnet 72. Further, by making the corner portion of the magnet 72 a surface, the shape is such that stress concentration is difficult to be made, and the strength of the magnet 72 can be increased. Therefore, the cracking of the magnet 72 can be further reduced.

Further, the angle of the inclined surface 85 is formed to be 20 ° to 30 ° with respect to the axis C. Therefore, when the magnet cover 73 is attached, the ratio of the force along the axial direction to the force from the first side in the axial direction becomes large. By loosening the tilt angle of the tilted surface 85 in this way, the magnet cover 73 can be easily inserted from one end side in the direction of the rotation axis. Therefore, the assembling property of the magnet cover 73 can be improved.

In the present embodiment, the thickness of the magnet 72 in the radial direction is uniform in the circumferential direction in the plan view seen from the axial direction, but the configuration is not limited to this. That is, the radial thickness at the circumferential end of the magnet 72 may be smaller than the radial thickness at the circumferential intermediate portion.
Here, since the salient poles 76 project from both ends in the circumferential direction of the magnet 72, the magnet cover 73 is bent with the salient poles 76 as a starting point. Therefore, it is easy to avoid contact between the corners of the magnet 72 and the magnet cover 73 at both ends in the circumferential direction of the magnet 72. On the other hand, the circumferential middle portion of the magnet 72 is more likely to come into contact with the magnet cover 73 because it is separated from the salient pole 76.

Therefore, by making the radial thickness of the circumferential middle portion of the magnet 72 that is easy to contact thicker than that of both peripheral ends, the strength of the circumferential intermediate portion of the magnet 72 is increased more than that of both peripheral ends. be able to. By bringing such a circumferential middle portion of the magnet 72 into contact with the magnet cover 73, the radial movement of the magnet 72 is fixed. Therefore, the magnet cover 73 can be securely fixed and the cracking of the magnet 72 can be reduced.
Further, the thickness of the magnet 72 in the radial direction becomes thinner toward both ends in the circumferential direction, and the distance from the stator 6 becomes longer toward both ends in the circumferential direction of the magnet 72. Therefore, it is possible to suppress a sudden change in magnetic flux with respect to the stator 6 between the magnets 72 adjacent to each other in the circumferential direction. Therefore, the cogging torque can be reduced.

(First modification)
In the above-described embodiment, the configuration in which four engaging holes 79 of the rotor core 71 are formed has been described, but the configuration is not limited to this configuration. For example, as shown in FIG. 10, the number of engaging holes 79 may be other than four (for example, six). As a result, the force applied to the engaging claw 95 is dispersed, so that the strength of the magnet cover 73 can be increased.

(Second modification)
In the above-described embodiment, the configuration in which the engagement hole 79 is formed in a substantially trapezoidal shape in which the inner side in the radial direction is shorter than the outer side in the radial direction in a plan view perpendicular to the axial direction has been described. Not limited to just. For example, as shown in FIG. 11, the engagement hole 79 may be formed in a circular shape in a plan view perpendicular to the axial direction. As a result, the engagement hole 79 can be easily machined, so that workability can be improved.

(Second Embodiment)
Next, a second embodiment according to the present invention will be described with reference to FIG.
FIG. 12 is an enlarged partial cross-sectional view of the corner portion of the magnet 72 according to the second embodiment. In the following description, the same configurations as those in the first embodiment described above will be designated by the same reference numerals and description thereof will be omitted as appropriate (the same applies to the following embodiments).
As shown in FIG. 12, the difference between the second embodiment and the above-mentioned first embodiment is described above in that in the second embodiment, the avoidance portion is provided on the magnet cover 73 instead of the magnet 72. It is different from the first embodiment.
Specifically, the first bent portion 92 of the magnet cover 73 has an overhanging portion 99 overhanging over the entire circumference on the outer side in the axial direction, and the overhanging portion 99 is used as an avoiding portion. With such a configuration, the distance between the corner portion of the magnet 72 and the magnet cover 73 becomes long, and the contact between the corner portion of the magnet 72 and the magnet cover 73 can be easily avoided. The overhanging portion 99 may be similarly provided on the second bent portion 97 side.

Further, the avoidance portion (overhanging portion 99) of the second embodiment and the avoidance portion (inclined surface 85) of the first embodiment may be used in combination. In this case, the distance between the corner portion of the magnet 72 and the magnet cover 73 becomes further longer, and the contact between the corner portion of the magnet 72 and the magnet cover 73 is more likely to be avoided. Therefore, the cracking of the magnet 72 can be further reduced.

(Third Embodiment)
Next, a third embodiment according to the present invention will be described with reference to FIG.
FIG. 13 is a perspective view of the rotor core according to the third embodiment. As shown in FIG. 13, the difference between the third embodiment and the above-mentioned first embodiment is that in the third embodiment, the engaging hole 79 of the rotor core 71 is integrated with the shaft holding hole 78. In that respect, it differs from the above-described embodiment.
The engagement hole 79 provided in the rotor core 71 communicates with the shaft holding hole 78 in the radial direction. With such a configuration, the weight of the rotor core 71 can be reduced and the inertia can be improved, and a high-performance rotor 7 can be obtained. Further, since the contact area with the rotor core 71 is reduced when the shaft 31 is press-fitted, the press-fitting load of the shaft 31 can be reduced and workability can be improved. Further, since the stroke in the radial direction is extended with respect to the engaging hole 79, it becomes easy to chuck the engaging hole 79 when assembling the rotor 7. Therefore, workability can be improved.

Although preferable examples of the present invention have been described above, the present invention is not limited to these examples. It is possible to add, omit, replace, and make other changes to the configuration without departing from the spirit of the present invention. The present invention is not limited by the above description, but only by the scope of the accompanying claims.
For example, in the above-described embodiment, the case where the engaging portion (engaging hole 79 and engaging claw 95) is provided only on the first side in the axial direction of the rotor 7 has been described, but the present invention is not limited to this configuration. Similar engaging portions 79 and 95 may be provided on the second side in the axial direction of the rotor 7.

In addition, it is possible to replace the constituent elements in the above-described embodiment with well-known constituent elements as appropriate without departing from the spirit of the present invention, and the above-mentioned modifications may be appropriately combined.

1 ... Brushless wiper motor (motor)
6 ... stator 7 ... rotor 31 ... shaft 61 ... stator core 64 ... teeth 71 ... rotor core 72 ... magnet 73 ... magnet cover 76 ... salient pole 76b ... corner 78 ... shaft holding hole 79 ... engagement hole (engagement part)
85 ... Inclined surface (avoidance part)
91 ... First end face cover (end face cover)
92 ... First bent portion (bent portion)
93 ... Outer peripheral surface cover 94 ... Shaft through hole 95 ... Engagement claw (engagement part)
97 ... Second bent part (bent part)
98 ... Second end face cover (end face cover)
99 ... Overhanging part C ... Rotating axis (axis core)

Claims (9)

A shaft that rotates around the axis of rotation and
A rotor core that rotates around the axis of rotation in the radial direction,
A magnet arranged on the outer peripheral surface of the rotor core and
A magnet cover for covering the rotor core and the magnet is provided.
The rotor core is
A cylindrical portion having a shaft holding hole for holding the shaft,
A salient pole formed so as to project outward in the radial direction between the magnets adjacent to each other in the circumferential direction of the outer peripheral surface of the cylindrical portion.
Equipped with
The magnet cover is
The magnet, the rotor core, and the end face cover covering the one end face side in the rotation axis direction of the salient pole,
It extends from the outer peripheral edge of the end face cover along the rotation axis direction through a bent portion formed at a position corresponding to the corner portion of the magnet and the corner portion of the salient pole, and extends from the outer peripheral edge of the magnet and the salient pole. With an outer peripheral cover that covers
Equipped with
The rotor core's one end surface in the direction of the rotation axis and the end surface cover are provided with an engaging portion that engages the rotor core and the magnet cover so as not to rotate relative to each other.
At least one of the corner portion and the bent portion of the magnet is provided with an avoidance portion for avoiding contact with the other .
The engaging portion is
An engaging hole formed on one end surface of the cylindrical portion in the direction of the rotation axis,
It consists of an engaging claw formed on the end face cover and capable of engaging with the engaging hole.
A rotor characterized by that. An inclined surface is formed in the corner portion corresponding to the bent portion of the magnet so that the thickness in the radial direction becomes thinner toward one end side in the rotation axis direction, and the inclined surface is referred to as the avoidance portion. The rotor according to claim 1, wherein the rotor is characterized in that. The rotor according to claim 2, wherein the angle of the inclined surface is 20 ° to 30 ° with respect to the rotation axis. Any of claims 1 to 3, wherein the bent portion has an overhanging portion extending over the entire circumference on the outside in the direction of the rotation axis, and the overhanging portion is used as the avoiding portion. Or the rotor according to item 1. The one according to any one of claims 1 to 4, wherein the magnet has a radial thickness at the circumferential end portion smaller than a radial thickness at the circumferential intermediate portion. Rotor. The one according to any one of claims 1 to 5, wherein the engaging hole is formed in the circumferential intermediate portion of the salient poles adjacent to each other in the circumferential direction in the cylindrical portion. Rotor. The rotor according to any one of claims 1 to 6, wherein the engaging hole communicates with the shaft holding hole in the radial direction. It comprises an annular stator core and a stator having a plurality of teeth protruding radially inward from the inner peripheral surface of the stator core.
A motor according to any one of claims 1 to 7, wherein a rotor according to any one of claims 1 is provided inside the teeth in the radial direction. A brushless wiper motor comprising the motor according to claim 8 for a wiper device of a vehicle.

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