JP7330011B2 - Rotors, motors and brushless wiper motors - Google Patents

Description

The present invention relates to rotors, motors and brushless wiper motors.

Conventionally, brushless wiper motors have been applied to drive wipers of vehicles.
As this type of motor, there is known a surface permanent magnet (SPM) motor in which permanent magnets are arranged on the outer peripheral surface of a rotor core. Various techniques have been proposed for surface permanent magnet motors to prevent permanent magnets from scattering due to centrifugal force when the rotor rotates.

For example, Patent Document 1 discloses a configuration of a motor including a rotor core, a plurality of permanent magnets arranged on the outer peripheral surface of the rotor core, and salient poles protruding radially outward between the permanent magnets adjacent in the circumferential direction. is disclosed. According to the technique described in Patent Document 1, the salient pole is provided with a convex portion that protrudes in the circumferential direction on the end face facing the permanent magnet. Radial movement of the magnet is restricted.

WO2019/017161

However, in the technique described in Patent Document 1, since it is necessary to form convex portions on the salient poles of the rotor core, the shape of the rotor core becomes complicated, which may increase the manufacturing cost.
On the other hand, as another method for preventing scattering of permanent magnets, a configuration in which a cylindrical cover is provided around the outer peripheral portion of the permanent magnets is generally known. However, when the cover is arranged on the outer periphery of the rotor in this way, the radial length of the salient poles is restricted by the cover, and the gap between the salient poles and the stator increases, which may reduce the motor torque.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a rotor that stably retains a permanent magnet with a low-cost, simple structure and improves motor torque, a motor using this rotor, and a brushless wiper motor.

In order to solve the above problems, a rotor according to the present invention rotates about an axis and includes a rotor core having a mounting hole formed in an end face in the axial direction; a permanent magnet having at least one axial end projecting outward from the rotor core in the axial direction; a cover member holding the end of the permanent magnet projecting axially from the rotor core; a fixing member for fixing the cover member to the rotor core, wherein the cover member includes a radial holding portion that contacts the outer peripheral surface of the permanent magnet; and a radially inner side of the rotor core from an end of the radial holding portion an axial holding portion provided in a part of the circumferential holding portion and in contact with the end face of the permanent magnet in the axial direction; and the radial direction of the circumferential holding portion. and an engaging portion disposed between the circumferential holding portions adjacent in the circumferential direction of the rotor core, wherein the fixing member is located outside the cover member in the axial direction. a main body portion that protrudes inward in the axial direction from the main body portion and is arranged outside the engaging portion of the cover member in the radial direction and is inserted into the mounting hole of the rotor core; or a protrusion to be press-fitted .

In the rotor according to the present invention, a plurality of the permanent magnets are arranged in the circumferential direction of the rotor core, and the rotor core is positioned radially outward of the rotor core and adjacent to the permanent magnets in the circumferential direction. A salient pole protruding therebetween is provided, and the fixing member restricts movement of the cover member in the axial direction.

In the rotor according to the present invention, the protrusion includes a first protrusion that abuts on the engaging portion of the cover member, and is provided outside the first protrusion in the radial direction. and a second protrusion having a short protrusion length along the axial direction.

In the rotor according to the present invention, the cover member is fixed to the rotor core by inserting or press-fitting the first protrusion into the mounting hole of the rotor core.

The rotor according to the present invention is characterized in that the cover member is an elastic member.

A motor according to the present invention includes the rotor described above, an annular stator having a plurality of teeth arranged at intervals on an outer peripheral portion of the rotor and formed radially inward of the rotor core; and coils wound around teeth, wherein the stator faces the rotor inside the cover member in the axial direction.

A brushless wiper motor according to the present invention is characterized by comprising the motor described above for use in a vehicle wiper device.

According to the present invention, it is possible to provide a rotor that stably holds permanent magnets and improves motor torque with a low-cost and simple configuration, and a motor and a brushless wiper motor that use this rotor.

Sectional drawing of the brushless wiper motor which concerns on 1st Embodiment. Sectional drawing which follows the II-II line of FIG. The perspective view of the rotor which concerns on 1st Embodiment. 3 is an exploded view of the rotor according to the first embodiment; FIG. FIG. 4 is a cross-sectional view taken along line VV of FIG. 3; The perspective view of the cover member which concerns on 1st Embodiment. FIG. 6 is a cross-sectional view taken along line VII-VII of FIG. 5; The perspective view of the fixing member which concerns on 1st Embodiment. The perspective view of the rotor which concerns on 2nd Embodiment. The exploded view of the rotor which concerns on 2nd Embodiment. FIG. 10 is a cross-sectional view taken along line XI-XI of FIG. 9; Sectional drawing along the XII-XII line of FIG.

Next, embodiments of the present invention will be described based on the drawings.

(First embodiment)
(Brushless wiper motor) (Motor)
FIG. 1 is a cross-sectional view of a brushless wiper motor 1 according to the first embodiment.
A brushless wiper motor 1 (hereinafter simply referred to as motor 1) serves as a drive source for electrical components mounted on a vehicle, for example. The electrical equipment is, for example, a wiper device (not shown). A wiper device is provided on a window glass (not shown) of a vehicle, and wipes off rain, dirt, etc. adhering to the window glass to ensure a driver's field of vision.
Note that the motor 1 may be used as a motor 1 other than a brushless wiper motor.

The motor 1 includes a motor section 2 , a deceleration section 3 that decelerates and outputs the rotation of the motor section 2 , and a controller section 4 that controls the driving of the motor section 2 .
In the following description, simply referring to the axial direction means the axial direction of the rotating shaft (shaft 31) of the motor section 2, and simply referring to the circumferential direction means the circumferential direction of the shaft 31. When simply referring to the radial direction, It shall mean the radial direction of the shaft 31 .

(Motor part)
The motor unit 2 includes a motor case 5, an annular stator 6 housed in the motor case 5, a rotor 7 provided radially inside the stator 6 and rotatable with respect to the stator 6, It has The motor unit 2 is a so-called brushless motor that does not require brushes when supplying power to the stator 6 .

The motor case 5 is made of a material having excellent heat dissipation properties, such as die-cast aluminum. The motor case 5 is composed of a first motor case 11 and a second motor case 12 which are axially separable. The first motor case 11 and the second motor case 12 are each formed in a cylindrical shape with a bottom.
The first motor case 11 covers the motor section 2 from one side in the axial direction. The first motor case 11 includes a circular first bottom portion 11a, a cylindrical first side portion 11b protruding in the other axial direction from the outer peripheral portion of the first bottom portion 11a, and a and a first edge 11c protruding radially outward from the other end over the entire circumferential direction. A bolt hole (not shown) is formed through the first edge portion 11c in the axial direction.

The second motor case 12 covers the motor section 2 from the other side in the axial direction. The second motor case 12 includes a second bottom portion 12a, a tubular second side portion 12b that protrudes in one axial direction from the outer peripheral portion of the second bottom portion 12a, and one end of the second side portion 12b in the axial direction. and a second edge portion 12c that protrudes radially outward from the portion along the entire circumferential direction. The second motor case 12 is formed integrally with the gear case 13 of the reduction section 3 so that the second bottom portion 12 a is joined to the gear case 13 . A bolt hole (not shown) is formed through the second edge portion 12c in the axial direction. A hole 14 through which the shaft 31 of the rotor 7 can be inserted is formed at substantially the center in the radial direction of the second bottom portion 12a.

The first edge portion 11c of the first motor case 11 and the second edge portion 12c of the second motor case 12 are in axial contact with each other. The bolt holes formed in the first edge portion 11c and the second edge portion 12c are formed so as to be coaxial when the first edge portion 11c and the second edge portion 12c are in contact with each other. A bolt 17 is inserted into the bolt hole. Thereby, the first edge portion 11c and the second edge portion 12c are fitted together to form the motor case 5 having an internal space. A stator 6 is arranged in the inner space of the motor case 5 so as to be fitted to the inner peripheral surfaces of the first motor case 11 and the second motor case 12 .

(stator)
FIG. 2 is a cross-sectional view along line II-II of FIG.
As shown in FIGS. 1 and 2, the stator 6 is integrally formed with an annular core portion 21 arranged coaxially with the shaft 31 and a plurality of teeth 22 protruding radially inward from the core portion 21. and coils 24 attached to the teeth 22 of the stator core 23 . The outer peripheral surface of the stator 6 is fixed to the inner peripheral surface of the motor case 5 and applies a rotating magnetic field to the rotor 7 .
The stator core 23 is configured by laminating electromagnetic steel plates in the axial direction. Note that the stator core 23 may be a so-called dust core.

As shown in FIG. 2 , each tooth 22 includes a tooth body 25 protruding radially inward from the inner peripheral surface of the core portion 21 and a collar portion 26 extending circumferentially from the radially inner end of the tooth body 25 . and are integrally molded. Slots 27 are formed between the flanges 26 adjacent in the circumferential direction.

As shown in FIG. 1, the inner peripheral surface of the core portion 21 and the teeth 22 are covered with an insulator 28 made of resin. A coil 24 is wound around each tooth 22 from above the insulator 28 . Each coil 24 generates a magnetic field for rotating the rotor 7 by power supply from the controller unit 4 .

(rotor)
FIG. 3 is a perspective view of the rotor 7 according to the first embodiment.
The rotor 7 is rotatably provided inside the stator 6 in the radial direction with a minute gap therebetween (see FIG. 1). The rotor 7 includes a shaft 31 (see FIG. 1) that rotates around the axis C, a cylindrical rotor core 32 that rotates integrally with the shaft 31 about the axis C in the radial direction, and a plurality of rotor cores 32 arranged on the outer peripheral surface of the rotor core 32 . It includes (in this embodiment, four) permanent magnets 33 , cover members 34 arranged at both ends of the rotor core 32 in the axial direction, and fixing members 35 fixing the cover members 34 to the rotor core 32 . The shaft 31 is formed integrally with a worm shaft 54 that constitutes the reduction section 3, which will be described later.

FIG. 4 is an exploded view of the rotor 7 according to the first embodiment.
The rotor core 32 is configured by laminating a plurality of metal plates in the axial direction. Note that the rotor core 32 may be a so-called dust core. The rotor core 32 is integrally formed with a cylindrical portion 36 having a shaft holding hole 38 in the center in the radial direction, and salient poles 37 protruding radially outward from the outer peripheral surface of the cylindrical portion 36 . A shaft 31 (see FIG. 1) is press-fitted into the shaft holding hole 38 . Alternatively, the shaft 31 may be inserted into the shaft holding hole 38 and the inner peripheral surface of the rotor core 32 may be fixed to the outer peripheral surface of the shaft 31 using an adhesive or the like.

A plurality of (four in this embodiment) mounting holes 39 are formed in the cylindrical portion 36 at regular intervals in the circumferential direction. The mounting hole 39 is for fixing the fixing member 35 to the rotor core 32 . The mounting hole 39 is formed in a circular shape when viewed from the axial direction. The mounting hole 39 axially penetrates the rotor core 32 in parallel with the axis C. As shown in FIG.

The salient poles 37 are provided at positions corresponding to the mounting holes 39 in the circumferential direction. A plurality of salient poles 37 (four in this embodiment) are formed at regular intervals in the circumferential direction. The axial length of each salient pole 37 is equal to the axial length of the cylindrical portion 36 . A U-shaped groove 40 is formed along the entire axial direction at the radially outer tip of the salient pole 37 .
On the outer peripheral surface of the cylindrical portion 36 formed in this manner, permanent magnets 33 are arranged between two salient poles 37 adjacent in the circumferential direction. In other words, the salient poles 37 are arranged between the permanent magnets 33 adjacent in the circumferential direction. The permanent magnets 33 are fixed to the rotor core 32 by, for example, an adhesive.

The permanent magnets 33 are arranged between the salient poles 37 of the rotor core 32 with their longitudinal direction along the axial direction. A plurality of permanent magnets 33 are arranged such that magnetic flux lines 80 (see FIG. 2) directed radially outward and magnetic flux lines directed radially inward are alternately arranged in the circumferential direction.

FIG. 5 is a cross-sectional view along line VV of FIG.
The axial length of the permanent magnets 33 is longer than the axial length of the rotor core 32 . Both ends of the permanent magnet 33 in the axial direction protrude outward in the axial direction from core end faces 32s (axial end faces of the rotor core in the claims) facing the axial direction of the rotor core 32 .

As shown in FIG. 2, the permanent magnet 33 is formed in a sector shape when viewed from the axial direction. When viewed from the axial direction, the radially outer outer surface 81 and the radially inner inner surface 82 of the permanent magnet 33 are formed in arcs having different arc centers. Specifically, the arc center of the inner surface 82 coincides with the axis C of the shaft 31 , and the arc center of the outer surface 81 is set closer to the outer peripheral surface of the corresponding rotor core 32 than the axis C of the shaft 31 . As a result, the permanent magnet 33 has a radial thickness smaller at the circumferential end portions than a radial thickness at the circumferential intermediate portion. That is, the gap between the outer surface 81 of the permanent magnet 33 and the inner peripheral surface of the tooth 22 is the smallest at the center of the permanent magnet 33 in the circumferential direction, and the gap gradually increases with increasing distance from the center in the circumferential direction. is configured to be
The inner surface 82 of the permanent magnet 33 formed in this manner is adhered to the outer peripheral surface of the cylindrical portion 36 of the rotor core 32 . The side surfaces 83, 83 positioned on both sides in the circumferential direction of the permanent magnet 33 when viewed in the axial direction are in contact with the salient poles 37 facing each other.

(Cover member)
FIG. 6 is a perspective view of the cover member 34 according to the first embodiment. FIG. 7 is a cross-sectional view taken along line VII--VII of FIG.
As shown in FIG. 6, the cover member 34 is made of an elastic member. Specifically, the cover member 34 is formed in a belt shape by bending an elastic sheet metal such as spring steel. As shown in FIG. 7 , the cover member 34 holds the end of the permanent magnet 33 protruding from the core end surface 32 s facing the axial direction of the rotor core 32 to the opposite side of the rotor core 32 in the axial direction. As shown in FIGS. 6 and 7 , the cover member 34 includes a radial holding portion 42 that contacts the outer peripheral surface (outer surface 81 ) of the permanent magnet 33 and a circumferential holding portion 43 that contacts the side surface 83 of the permanent magnet 33 . , the axial holding portion 44 abutting on the magnet end face 33s facing the axial direction of the permanent magnet 33 (the axial end face of the permanent magnet in claims) and the engagement provided between the permanent magnets 33 adjacent in the circumferential direction. a portion 45;

The radial holding portion 42 covers the outer surface 81 of the permanent magnet 33 from the radial outside. The radial holding portion 42 is adjacent to the radial holding portion 42a covering the outer surface 81 of one permanent magnet 33a, which is one of the plurality of permanent magnets 33, and the one permanent magnet 33a in the circumferential direction. and another radial holding portion 42b that covers a part of the outer surface 81 of another permanent magnet 33b.
The one radial holding portion 42 a covers the entire circumference of the outer surface 81 at the end of the one permanent magnet 33 a projecting axially from the rotor core 32 . One radial holding portion 42 a curves along the outer surface 81 of the permanent magnet 33 .
A pair of other radial holding portions 42b are provided on both sides in the circumferential direction of the one radial holding portion 42a with a gap therebetween. The other radial holding portion 42b is formed integrally with the one radial holding portion 42a via a circumferential holding portion 43 and an engaging portion 45, which will be described later in detail. Each of the other radial holding portions 42b covers a part of the outer surface 81 located on the one permanent magnet 33a side at the end of the other permanent magnet 33b protruding from the rotor core 32 in the axial direction. The other radial holding portion 42 b curves along the outer surface 81 of the permanent magnet 33 .

The circumferential holding portion 43 protrudes radially inward from the end portion of the radial holding portion 42 . Circumferential direction holding portion 43 includes one circumferential direction holding portion 43a arranged along the side surface 83 of one permanent magnet 33a from both ends of one radial direction holding portion 42a, and one end portion of another permanent magnet 33b. and another circumferential holding portion 43b arranged along the side surface 83 of another permanent magnet 33b.
A pair of circumferential holding portions 43a are provided at both ends of one radial holding portion 42a. One circumferential holding portion 43 a protrudes from both end portions of the radial holding portion 42 to a position corresponding to the mounting hole 39 of the rotor core 32 . The one circumferential holding portion 43a is formed linearly.
The other circumferential holding portion 43b faces the pair of circumferential holding portions 43a. The other circumferential holding portion 43b is formed linearly along a side surface 83 facing one permanent magnet 33a of the other permanent magnets 33b. Another radial holding portion 42b is formed integrally with the radially outer end portion of the other circumferential holding portion 43b.

As shown in FIG. 6 , the axial holding portion 44 is provided at a radial intermediate portion of the circumferential holding portion 43 . The axial holding portion 44 is integrally formed with the circumferential holding portion 43 . The axial holding portion 44 has one axial holding portion 44a connected to one circumferential holding portion 43a and another axial holding portion 44b connected to another circumferential holding portion 43b.
The one axial holding portion 44a protrudes from the one circumferential holding portion 43a toward the one permanent magnet 33a side in the circumferential direction. The one axial holding portion 44a is formed in a wavy shape when viewed from the axial direction. A magnet end face 33s of one permanent magnet 33a is in contact with one axial holding portion 44a.
The other axial holding portion 44b protrudes from the other circumferential holding portion 43b toward the other permanent magnet 33b side in the circumferential direction. The other axial holding portion 44b is formed in a wavy shape when viewed from the axial direction. A magnet end surface 33s of another permanent magnet 33b is in contact with the other axial holding portion 44b.

As shown in FIGS. 6 and 7 , the engaging portion 45 is provided at the radial inner end portion of the circumferential holding portion 43 . The engaging portion 45 is formed integrally with the circumferential holding portion 43 . When viewed from the axial direction, the engaging portion 45 is formed in a semicircular shape that opens radially outward. One end of the engaging portion 45 is connected to the radially inner end portion of the one circumferential holding portion 43a. The other end of the engaging portion 45 is connected to the radial inner end portion of the other circumferential holding portion 43b. The engaging portion 45 is arranged radially inside the mounting hole 39 of the rotor core 32 .
As a result, when viewed from the axial direction, the cover member 34 includes one radial holding portion 42a, one circumferential holding portion 43a connected to the one radial holding portion 42a and protruding radially inward, and one radial holding portion 43a. An engaging portion 45 connected to the circumferential holding portion 43a, another circumferential holding portion 43b connected to the engaging portion 45 and protruding radially outward, and another circumferential holding portion 43b connected to the other circumferential holding portion 43b. The radial holding portions 42b are connected to each other in this order.

The cover member 34 formed in this way is entirely disposed on the opposite side (outside in the axial direction) of the rotor core 32 from the core end surface 32s of the rotor core 32 . The cover members 34 are arranged symmetrically with respect to the axis C of the rotor core 32 and arranged on both sides of the rotor core 32 in the axial direction. That is, a total of four cover members 34 are provided for one rotor 7 .

Here, as shown in FIG. 4, the pair of cover members 34 arranged on one side in the axial direction of the rotor core 32 is arranged at an angle of 90° around the axis C with respect to the pair of cover members 34 arranged on the other side in the axial direction. placed in a rotated position. Specifically, the plurality of permanent magnets 33 are numbered from 1 to 4 in order in the circumferential direction, and the radial holding portions 42a, 42a of the pair of cover members 34, 34 arranged on one side in the axial direction. 42a covers the outer surface 81 of the number 1 and number 3 permanent magnets 33 . At this time, the one radial holding portions 42a, 42a of the pair of cover members 34, 34 arranged on the other side in the axial direction cover the outer surfaces 81 of the second and fourth permanent magnets 33, respectively.

(fixing member 35)
FIG. 8 is a perspective view of the fixing member 35 according to the first embodiment.
A fixing member 35 that fixes the cover member 34 to the rotor core 32 covers the cover member 34 from the opposite side of the rotor core 32 in the axial direction. The fixed member 35 has a main body portion 46 arranged on the opposite side of the rotor core 32 in the axial direction from the cover member 34 , and a projecting portion 47 protruding from the main body portion 46 toward the rotor core 32 side in the axial direction.

The body portion 46 is formed in an annular shape centered on an axis C with a shaft insertion hole 85 formed in the center in the radial direction. The shaft insertion hole 85 is formed in a circular shape coaxial with the axis C. As shown in FIG. As shown in FIG. 5 , the outer diameter of the main body portion 46 is approximately the same as the outer diameter of the rotor core 32 and smaller than the outer diameters of the permanent magnets 33 and the cover member 34 . An end surface of the body portion 46 facing the rotor core 32 side is in contact with the cover member 34 .
As shown in FIG. 8, the inner peripheral portion of the main body portion 46 is formed with an overhang portion 86 that protrudes radially inward. A plurality of (four in this embodiment) protrusions 86 are provided at intervals in the circumferential direction.

A relief portion 87 is formed between the outer peripheral portion of the body portion 46 and the shaft insertion hole 85 . The relief portion 87 is a hole axially penetrating the body portion 46 . The relief portion 87 is formed in a rectangular shape when viewed from the axial direction. The relief portion 87 is provided at a position corresponding to the axial holding portion 44 of the cover member 34 when the fixing member 35 axially covers the cover member 34 (see also FIG. 3). The escape portion 87 accommodates the axial holding portion 44 of the cover member 34 . A plurality of escape portions 87 (eight in this embodiment) are provided in the circumferential direction.

The projecting portion 47 has a first projecting portion 48 and a second projecting portion 49 provided radially outside the first projecting portion 48 .
The first projecting portion 48 is integrally formed with the body portion 46 . The first projecting portion 48 is provided on the projecting portion 86 of the main body portion 46 . As shown in FIG. 5 , the first projecting portion 48 protrudes from the main body portion 46 to the inside of the rotor core 32 from the core end surface 32 s of the rotor core 32 . The first protrusion 48 is press-fitted into the mounting hole 39 of the rotor core 32 . The fixing member 35 is fixed to the rotor core 32 by press-fitting the first protrusion 48 into the mounting hole 39 . A plurality (four in this embodiment) of the first protrusions 48 are provided in the circumferential direction. The first projecting portion 48 is arranged at a position corresponding to the engaging portion 45 of the cover member 34 and is in contact with the engaging portion 45 from the outside in the radial direction (see FIG. 7).

The second projecting portion 49 is integrally formed with the body portion 46 . The second protrusion 49 is provided at the same position as the first protrusion 48 in the circumferential direction. The second projecting portion 49 is arranged between adjacent relief portions 87 . The protrusion length of the second protrusion 49 is shorter than the protrusion length of the first protrusion 48 . Specifically, when the fixing member 35 is attached to the rotor core 32, the length of the second protrusion 49 does not reach the core end surface 32s. As shown in FIG. 7, the outer diameter of the second protrusion 49 is larger than the outer diameter of the first protrusion. The second projecting portion 49 is arranged between the one circumferential holding portion 43a and the other circumferential holding portion 43b of the cover member 34, and contacts the one circumferential holding portion 43a and the other circumferential holding portion 43b. in contact with

The rotor 7 formed in this way is arranged so that the rotor core 32 of the rotor 7 and the stator 6 face each other in the radial direction when they are arranged on the inner peripheral portion of the stator 6 with a gap therebetween. In other words, the stator 6 radially faces the rotor 7 axially inside the cover member 34 . As a result, the cover member 34 is not placed in the gap between the stator 6 and the rotor 7, and the gap is kept narrow.

(Reduction part)
Returning to FIG. 1 , the reduction section 3 includes a gear case 13 to which the motor case 5 is attached at one end in the axial direction, and a worm reduction mechanism 51 housed in the gear case 13 . The gear case 13 is made of a material having excellent heat dissipation properties, such as die-cast aluminum. The gear case 13 is formed in a box-like shape with one side open, and has a gear housing portion 52 for housing a worm speed reduction mechanism 51 therein. A second motor case 12 is integrally formed on one side of the gear case 13 in the axial direction. The side wall of the gear case 13 is formed with an opening 15 that communicates the hole 14 of the second motor case 12 with the gear housing portion 52 at a portion where the second motor case 12 is integrally formed. Thus, the motor case 5 is provided at one axial end of the gear case 13 .

A cylindrical bearing boss 53 protrudes from the side wall of the gear case 13 . The bearing boss 53 is for rotatably supporting the output shaft 60 of the worm speed reduction mechanism 51, and has a slide bearing (not shown) on its inner peripheral surface. Furthermore, an O-ring (not shown) is attached to the inner peripheral edge of the tip of the bearing boss 53 . This prevents dust and water from entering from the outside through the bearing boss 53 . A plurality of ribs are provided on the outer peripheral surface of the bearing boss 53 . This ensures the rigidity of the bearing boss 53 .

The worm speed reduction mechanism 51 housed in the gear housing portion 52 is composed of a worm shaft 54 and a worm wheel 55 meshed with the worm shaft 54 . The worm shaft 54 is arranged coaxially with the shaft 31 of the motor section 2 . Both ends of the worm shaft 54 are rotatably supported by bearings 56 and 57 provided in the gear case 13 . The axial end of the worm shaft 54 on the side of the motor unit 2 protrudes through the bearing 56 to the opening 15 of the gear case 13 . The protruding end of the worm shaft 54 and the end of the shaft 31 of the motor section 2 are joined together to integrate the worm shaft 54 and the shaft 31 . The worm shaft 54 and the shaft 31 may be integrally formed by molding the worm shaft 54 portion and the shaft 31 portion from one base material.

A worm wheel 55 that meshes with the worm shaft 54 is provided with an output shaft 60 at the radial center of the worm wheel 55 . The output shaft 60 is arranged coaxially with the rotation axis direction of the worm wheel 55 and protrudes outside the gear case 13 via the bearing boss 53 of the gear case 13 . A spline 61 that can be connected to an electrical component (not shown) is formed at the projecting tip of the output shaft 60 .

A sensor magnet (not shown) is provided at the radial center of the worm wheel 55 on the side opposite to the side where the output shaft 60 projects. This sensor magnet constitutes one of the rotational position detectors for detecting the rotational position of the worm wheel 55 . The magnetic detection element 70, which constitutes the other of the rotational position detection units, is provided in the controller unit 4, which is arranged to face the worm wheel 55 on the sensor magnet side of the worm wheel 55 (on the side of the opening 15 of the gear case 13). .

(controller part)
The controller section 4 that controls the driving of the motor section 2 has a controller board 71 on which the magnetic detection element 70 is mounted, and a cover 72 provided to close the opening 15 of the gear case 13 . The controller board 71 is arranged to face the sensor magnet side of the worm wheel 55 (the opening 15 side of the gear case 13).

The controller board 71 is a so-called epoxy board on which a plurality of conductive patterns (not shown) are formed. Terminals of the coils 24 drawn out from the stator core 23 of the motor section 2 are connected to the controller board 71, and terminals of a connector provided on the cover 72 (none of which are shown) are electrically connected. there is In addition to the magnetic detection element 70, the controller board 71 is mounted with a power module (not shown) composed of switching elements such as FETs (Field Effect Transistors) for controlling the current supplied to the coil 24. ing. Further, the controller board 71 is mounted with a capacitor (not shown) and the like for smoothing the voltage applied to the controller board 71 .

A cover 72 covering the controller board 71 configured in this way is made of resin. The cover 72 is formed to protrude slightly outward. The inner surface side of the cover 72 serves as a controller accommodating portion 73 that accommodates the controller board 71 and the like.
A connector (not shown) is integrally formed on the outer peripheral portion of the cover 72 . This connector is fitted with a connector extending from an external power source (not shown). The controller board 71 is electrically connected to terminals of a connector (not shown). As a result, power from the external power supply is supplied to the controller board 71 .

Furthermore, a fitting portion 74 that fits with the end portion of the side wall of the gear case 13 protrudes from the opening edge of the cover 72 . The fitting portion 74 is composed of two walls 74 a and 74 b along the opening edge of the cover 72 . Then, the ends of the side walls of the gear case 13 are inserted (fitted) between these two walls 74a and 74b. Thereby, a labyrinth portion 75 is formed between the gear case 13 and the cover 72 . The labyrinth portion 75 prevents dust and water from entering between the gear case 13 and the cover 72 . The gear case 13 and the cover 72 are fixed by fastening bolts (not shown).

(Motor manufacturing procedure)
Next, a procedure for manufacturing the motor 1 described above will be described.
First, the rotor 7 is manufactured. In the manufacturing procedure of the rotor 7, first, the permanent magnets 33 are adhered to the outer peripheral surface of the rotor core 32 using an adhesive. At this time, the permanent magnets 33 are arranged so that both ends of the permanent magnets 33 in the axial direction protrude outward in the axial direction from the core end faces 32 s of the rotor core 32 . Next, a cover member 34 is attached to the end of the permanent magnet 33 projecting from the rotor core 32 . Specifically, one radial holding portion 42a is brought into contact with the outer surface 81 of one permanent magnet 33a, and another radial holding portion is brought into contact with the outer surface 81 of another permanent magnet 33b adjacent to the one permanent magnet 33a. 42b are brought into contact. A circumferential holding portion 43 and an engaging portion 45 are arranged between the permanent magnets 33 adjacent in the circumferential direction. Also, the axial holding portion 44 is brought into contact with the magnet end surface 33 s of the permanent magnet 33 . Thus, the permanent magnet 33 is positioned with respect to the cover member 34 by the radial holding portion 42, the circumferential holding portion 43, and the axial holding portion 44, and the permanent magnet 33 and the cover member 34 are fixed.

Next, the fixing member 35 is attached to the rotor core 32 . Specifically, the fixing member 35 is fixed to the rotor core 32 by press-fitting the first protrusion 48 of the fixing member 35 into the mounting hole 39 of the rotor core 32 . At this time, the body portion 46 of the fixing member 35 covers the cover member 34 from the side opposite to the rotor core 32 in the axial direction, thereby restricting the movement of the cover member 34 in the axial direction. Further, the first projecting portion 48 of the fixing member 35 is arranged radially outside the engaging portion 45 of the cover member 34 . By engaging the engaging portion 45 with the first protrusion 48 , the first protrusion 48 restricts movement of the cover member 34 in the radial direction and the circumferential direction. By fixing the fixing member 35 to the rotor core 32 in this way, the cover member 34 is fixed to the rotor core 32 by the fixing member 35 .
After that, the permanent magnets 33 attached to the rotor core 32 are magnetized so that N poles and S poles are arranged alternately in the circumferential direction. Thereby, the rotor 7 is manufactured.

Next, the stator 6 is manufactured. In the manufacturing procedure of the stator 6 , the coils 24 are wound around the teeth 22 of the stator core 23 . As a result, the stator 6 to which the coils 24 are attached is manufactured. The order of manufacturing the stator 6 and the rotor 7 may be reversed.

Next, the manufactured stator 6 is fixed to the inner wall of the second motor case 12 . Next, the rotor 7 is arranged radially inside the stator 6 with a gap therebetween. At this time, the stator 6 and the rotor core 32 of the rotor 7 are arranged to face each other in the axial direction. Finally, the first motor case 11 is put on and the first motor case 11 and the second motor case 12 are fastened with bolts 17 . Thus, manufacturing of the motor 1 is completed.

(action, effect)
Next, the actions and effects of the rotor 7 and the motor 1 described above will be described.
The rotor 7 includes a cover member 34 and a fixing member 35 provided axially outside the rotor core 32 . The cover member 34 holds both ends of the permanent magnet 33 protruding axially outward from the rotor core 32 , and the fixing member 35 fixes the cover member 34 to the rotor core 32 . As a result, the permanent magnet 33 can be stably held on the rotor core 32 with a simple configuration using the cover member 34 and the fixing member 35 . In particular, when the cover member 34 is made of sheet metal and the cover member 34 is made of a resin material, the cover member 34 and the fixing member 35 are easily formed. Therefore, the cover member 34 and the fixing member 35 can be configured simply and at low cost. Moreover, since the cover member 34 holds the corners of the permanent magnets 33 where stress tends to concentrate, the permanent magnets 33 can be protected and cracking of the permanent magnets 33 can be suppressed.

The cover member 34 and the fixing member 35 are arranged axially outside the core end surface 32s of the rotor core 32 facing the axial direction. Therefore, when the stator 6 is arranged at a position facing the rotor core 32 in the axial direction on the outer circumference of the rotor 7 , the cover member 34 and the fixing member 35 are not interposed in the gap between the rotor 7 and the stator 6 . Thereby, the gap can be narrowed compared to the case where the cover member 34 and the fixing member 35 are interposed in the gap. Therefore, the motor torque can be improved, and the performance of the motor can be enhanced. Also, the effective magnetic flux of the permanent magnet 33 is not blocked by the cover member 34 and the fixing member 35, and the effective magnetic flux can be used efficiently.
Therefore, it is possible to stably hold the permanent magnet 33 and provide the rotor 7 with improved motor torque with a low-cost and simple configuration.

The rotor core 32 has salient poles 37, and permanent magnets 33 are arranged between the salient poles 37 adjacent in the circumferential direction. Since the cover member 34 is arranged between the salient poles 37 (rotor core 32) and the fixed member 35 in the axial direction, the axial movement of the cover member 34 is restricted by fixing the fixed member 35 to the rotor core 32. can. Therefore, by covering the cover member 34 with the fixing member 35 from the axial direction, the cover member 34 can be attached to the rotor core 32 with a simple configuration.

The cover member 34 has a radial holding portion 42 , a circumferential holding portion 43 , an axial holding portion 44 and an engaging portion 45 . The radial holding portion 42 abuts on the outer peripheral surface of the permanent magnet 33 and restricts the movement of the permanent magnet 33 in the radial direction. The circumferential holding portion 43 is in contact with the side surface 83 of the permanent magnet 33 . The axial holding portion 44 abuts on the magnet end surface 33s of the permanent magnet 33 facing the axial direction, and restricts the movement of the permanent magnet 33 in the axial direction. Thus, the permanent magnet 33 can be stably held by the radial holding portion 42 , the circumferential holding portion 43 , and the axial holding portion 44 . The engaging portion 45 is arranged between the adjacent circumferential holding portions 43 , and the projecting portion 47 of the fixing member 35 is arranged outside the engaging portion 45 in the radial direction. Therefore, the engagement of the engaging portion 45 with the projecting portion 47 restricts the radially outward movement and the circumferential movement of the cover member 34 . Further, the movement of the cover member 34 in the axial direction is restricted by the body portion 46 of the fixing member 35 . Thereby, the cover member 34 can be easily fixed to the rotor core 32 .
The fixed member 35 is fixed to the rotor core 32 by press-fitting the protrusion 47 into the mounting hole 39 of the rotor core 32 . Therefore, the fixing member 35 can be attached to the rotor core 32 by an easy method.

The projecting portion 47 has a first projecting portion 48 and a second projecting portion 49 , and the first projecting portion 48 contacts the engaging portion 45 of the cover member 34 . As described above, the fixing member 35 has the first projection 48 that abuts against the engaging portion 45 of the cover member 34 and is press-fitted into the mounting hole 39 of the rotor core 32 . , the cover member 34 and the permanent magnet 33 held by the cover member 34 can be fixed. Further, the second protrusion 49 is provided radially outside of the first protrusion 48 and is arranged between one circumferential holding portion 43a and the other circumferential holding portion 43b. Here, for example, when the rotor 7 rotates, the permanent magnets 33 tend to move radially outward due to centrifugal force and press the radial direction holding portions 42 radially outward. They may deform in the direction of approaching each other. When the circumferential holding portions 43 a and 43 b approach each other, the other radial holding portion 42 b connected to the other circumferential holding portion 43 b separates from the outer peripheral surface of the permanent magnet 33 , and the permanent magnet 33 is removed from the cover member 34 . There is a risk. On the other hand, the second projecting portion 49 is arranged between the adjacent circumferential direction holding portions 43a and 43b and suppresses deformation of the circumferential direction holding portions 43a and 43b in a direction toward each other. It is possible to suppress the holding portion 42 b from being separated from the permanent magnet 33 . Therefore, separation between the permanent magnet 33 and the cover member 34 is suppressed, and the permanent magnet 33 can be held stably.

The fixing member 35 and the cover member 34 are fixed to the rotor core 32 by press-fitting the first protrusion 48 of the fixing member 35 into the mounting hole 39 of the rotor core 32 . In this way, the first protrusion 48 abuts against the engaging portion 45 of the cover member 34 to restrict the movement of the cover member 34 in the radial direction. It has the function to Further, the fixing member 35 and the cover member 34 can be fixed simply by inserting the first protrusion 48 into the mounting hole 39 of the rotor core 32 . Therefore, the fixing member 35 and the cover member 34 can be attached to the rotor 7 with a single and simple structure, and workability in manufacturing the rotor 7 can be improved.

Since the cover member 34 is an elastic member, the cover member 34 can be easily attached to the permanent magnet 33 by elastically deforming the cover member 34 . Moreover, in a state where the cover member 34 is attached to the permanent magnet 33, the stress that the permanent magnet 33 receives from the cover member 34 can be reduced, and cracking of the permanent magnet 33 can be suppressed.

The pair of cover members 34 arranged on one side of the rotor core 32 in the axial direction is arranged in a state rotated by 90° with respect to the pair of cover members 34 arranged on the other side in the axial direction. As a result, the four permanent magnets 33 have at least one end in the axial direction covered entirely by the radial holding portion 42a. Therefore, the plurality of permanent magnets 33 can be held uniformly and stably.

The motor includes the above-described rotor 7 and stator 6 , and the stator 6 faces the rotor 7 axially inside the cover member 34 . Thereby, the gap between the stator 6 and the rotor 7 can be narrowed without interposing the cover member 34 in the gap between the stator 6 and the rotor 7 . Thereby, the motor torque can be improved, and the performance of the motor 1 can be enhanced. The fixing member 35 fixes the cover member 34 to the rotor core 32 by covering the cover member 34 from the axial direction. Therefore, the effective magnetic flux of the permanent magnet 33 is not blocked by the cover member 34 and the fixing member 35, and the effective magnetic flux can be used efficiently.
Therefore, it is possible to provide a high-performance motor 1 having a rotor 7 that stably holds the permanent magnet 33 and has improved motor torque with a low-cost and simple configuration.
In addition, since the brushless wiper motor 1 is used as a wiper device for a vehicle, the brushless wiper motor 1 is provided with a rotor 7 that stably holds the permanent magnet 33 and improves the motor torque with a low-cost and simple configuration. A motor 1 can be provided.

(Second embodiment)
Next, a second embodiment according to the present invention will be described with reference to FIGS. 9 to 12. FIG.
FIG. 9 is a perspective view of the rotor 207 according to the second embodiment. FIG. 10 is an exploded view of the rotor 207 according to the second embodiment. 11 is a cross-sectional view taken along line XI-XI in FIG. 9. FIG. 12 is a cross-sectional view taken along line XII-XII in FIG. 11. FIG. In the following description, the same reference numerals are given to the same configurations as in the first embodiment described above, and the description thereof will be omitted as appropriate.
The difference between the second embodiment and the above-described first embodiment is that, in the second embodiment, the configurations of the cover member 34 and the fixing member 35 are different from those of the above-described first embodiment.

In the second embodiment, the cover member 234 holds the end of the permanent magnet 33 protruding axially from the core end surface 32s of the rotor core 32 . As shown in FIGS. 9 and 10, the cover member 234 is formed by bending a plate-like member, for example. Specifically, the cover member 234 includes a base portion 231 that abuts against the core end face 32s facing the axial direction of the rotor core 32, an arm portion 232 that protrudes radially outward from the base portion 231, and a and a pawl portion 233 connected to the outer end.
Mounting holes 39 are formed in the cylindrical portion 36 of the rotor core 32 between adjacent salient poles 37 in the circumferential direction. The mounting holes 39 are formed at equal intervals in the circumferential direction and penetrate the rotor core 32 in the axial direction.

As shown in FIG. 10, the base 231 is formed in an annular shape centering on the axis C. As shown in FIG. A plurality of (four in this embodiment) through holes 236 are formed in the base 231 . The through hole 236 axially penetrates the base portion 231 . The through hole 236 is provided coaxially with the mounting hole 39 of the rotor core 32 .
As shown in FIG. 9, the arm portion 232 is connected to the outer peripheral portion of the base portion 231 . The arm portion 232 is integrally formed with the base portion 231 . A plurality of (four in this embodiment) arm portions 232 are provided in the circumferential direction. The arm portions 232 are provided between through holes 236 formed in the base portion 231 in the circumferential direction. The arm portion 232 includes a rising portion 237 rising from the base portion 231 on the side opposite to the rotor core 32 along the axial direction, and a rising portion 237 extending radially outward from the upper end of the rising portion 237 (the end on the side opposite to the rotor core 32 in the axial direction). and a pressing portion 238 protruding from the bottom. The pressing portion 238 is provided at a position overlapping the salient pole 37 of the rotor core 32 when viewed from the axial direction. Protrusions 239 protruding in the circumferential direction are integrally formed on both side portions of the pressing portion 238 in the circumferential direction. The projecting portion 239 abuts on the magnet end surface 33 s of the permanent magnet 33 .

The claw portion 233 protrudes from the radially outer end portion of the arm portion 232 toward the rotor core 32 along the axial direction. The claw portion 233 is in contact with the outer peripheral surface (outer surface 81 ) of the permanent magnet 33 . The circumferential length of the claw portion 233 is longer than the circumferential length of the arm portion 232 . The claw portion 233 curves along the outer surface 81 of the permanent magnet 33 . Here, as shown in FIG. 12, the inner diameter r1 dimension of the claw portion 233 is equal to or smaller than the outer diameter r2 dimension of the salient pole 37 of the rotor core 32 (r1≦r2). In other words, the radially outer end portion of the salient pole 37 is located radially outside the inner peripheral surface of the claw portion 233 when viewed in the axial direction. More specifically, when viewed from the axial direction, the radially outer end of the salient pole 37 is located between the inner peripheral surface and the outer peripheral surface of the claw portion 233 in the radial direction.

As shown in FIGS. 9 and 10 , the fixing member 235 fixes the cover member 234 to the rotor core 32 by being inserted into the through hole 236 of the base 231 and the mounting hole 39 of the rotor core 32 . As shown in FIG. 11 , the fixing member 235 has an insertion portion 241 that is inserted into the through hole 236 and the mounting hole 39 , and head portions 242 that are provided at both ends of the insertion portion 241 in the axial direction. The fixing member 235 is, for example, a rivet.
The head portion 242 is in contact with the base portion 231 of the cover member 234 . Thereby, the fixing member 235 restricts the movement of the cover member 234 in the axial direction.

According to this embodiment, the cover member 234 has a base portion 231 , arm portions 232 and claw portions 233 . The fixing member 235 has an insertion portion 241 and a head portion 242 . The cover member 234 is fixed to the rotor core 32 by abutting the base portion 231 of the cover member 234 against the axial core end surface 32 s of the rotor core 32 and inserting the fixing member 235 into the through hole 236 . The arm portion 232 restricts the axial movement of the permanent magnet 33 by contacting the magnet end surface 33 s of the permanent magnet 33 . The claw portion 233 restricts radially outward movement of the permanent magnet 33 by contacting the outer surface 81 of the permanent magnet 33 . Thus, the permanent magnet 33 can be stably held by the base portion 231 , the arm portion 232 and the claw portion 233 .

Since the cover member 234 holds the end of the permanent magnet 33 protruding from the core end surface 32s of the rotor core 32, when the stator 6 is arranged on the outer periphery of the rotor 7, the cover member 234 is not in the gap between the rotor 7 and the stator 6. The gap can be narrowed without intervening. Thereby, the motor torque can be improved, and the performance of the motor 1 can be enhanced. Also, the effective magnetic flux of the permanent magnets 33 is not blocked by the cover member 234, so that the effective magnetic flux can be used efficiently.
Therefore, it is possible to provide the rotor 207 that stably holds the permanent magnet 33 and improves the motor torque with a low-cost and simple configuration.
Moreover, especially when a rivet is used as the fixing member 235, the structure of the fixing member 235 can be simplified.

In addition, the inner diameter r1 dimension of the claw portion 233 is equal to or smaller than the outer diameter r2 dimension of the salient pole 37 of the rotor core 32 . As a result, the salient poles 37 are positioned radially outside the inner peripheral surface of the claw portion 233 when viewed in the axial direction. Therefore, when the stator 6 is arranged on the outer periphery of the rotor 207, the gap between the salient poles 37 of the rotor 207 and the stator 6 can be narrowed regardless of the inner diameter size and thickness of the cover member. Therefore, the rotor 207 with improved motor torque can be provided.

Although preferred embodiments of the invention have been described above, the invention is not limited to these embodiments. Configuration additions, omissions, substitutions, and other changes are possible without departing from the scope of the present invention. The present invention is not limited by the foregoing description, but only by the scope of the appended claims.

For example, in the above-described embodiment, the axial end portions of the permanent magnets 33 protrude outward from the rotor core 32 in the axial direction, but the present invention is not limited to this configuration. At least one axial end of the permanent magnet 33 needs to protrude axially outward from the rotor core 32, and the other axial end of the permanent magnet 33 is flush with the core end surface 32s of the rotor core 32 in the axial direction. may be arranged so as to be In this case, the cover member 34 and the fixing member 35 may be arranged only on one side where the end of the permanent magnet 33 protrudes from the rotor core 32 . Moreover, the protrusion height of the permanent magnet 33 with respect to the core end surface 32s of the rotor core 32 may differ between one end and the other end. However, the configuration of the present embodiment in which one end and the other end of the permanent magnet 33 protrude from the core end surface 32s by the same length, and the cover member 34 and the fixing member 35 are provided at both ends of the rotor 7, There is an advantage in that the weight balance of the rotor 7 and the holding force of the permanent magnet 33 can be stably maintained.

The number of protrusions 47 and the number of permanent magnets 33 in the first embodiment and the number of fixing members 235 in the second embodiment are not limited to those of the above embodiments.
In the first embodiment, the mounting hole 39 of the rotor core 32 may be a concave portion that does not penetrate in the axial direction.
The arc center of the inner surface 82 and the arc center of the outer surface 81 of the permanent magnet 33 may coincide. It may be formed in a coaxial circular arc shape.

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

1... Motor (brushless wiper motor)
6... Stator 7... Rotor 32... Rotor core 32s... Core end face (end face in the axial direction of the rotor core)
33... Permanent magnet 33s... Magnet end face (end face in the axial direction of the permanent magnet)
34... Cover member 35... Fixed member 37... Salient pole 39... Mounting hole 42... Radial direction holding part 43... Circumferential direction holding part 44... Axial direction holding part 45... Engagement part 46... Body part 47... Protrusion part 48... Third One protrusion 49 Second protrusion 231 Base 232 Arm 233 Claw 236 Through hole 241 Insertion portion 242 Head C Axis

Claims (7)

a rotor core that rotates about an axis and has a mounting hole formed in an end face of the axis in the axial direction ;
a permanent magnet arranged on the outer peripheral surface of the rotor core and having at least one axial end projecting outward from the rotor core in the axial direction;
a cover member that holds the ends of the permanent magnets that protrude from the rotor core in the axial direction;
a fixing member that fixes the cover member to the rotor core;
with
The cover member is
a radial holding portion that abuts on the outer peripheral surface of the permanent magnet;
a circumferential holding portion protruding radially inward of the rotor core from an end portion of the radial holding portion;
an axial holding portion provided in a part of the circumferential holding portion and in contact with the axial end surface of the permanent magnet;
an engaging portion provided at the radially inner end portion of the circumferential holding portion and disposed between the circumferential holding portions adjacent in the circumferential direction of the rotor core;
has
The fixing member is
a body portion arranged outside the cover member in the axial direction;
a protrusion that protrudes inward in the axial direction from the main body, is arranged outside the engaging portion of the cover member in the radial direction, and is inserted or press-fitted into the mounting hole of the rotor core;
A rotor characterized by having A plurality of permanent magnets are arranged in a circumferential direction of the rotor core,
the rotor core has salient poles projecting radially outward of the rotor core and passing between the permanent magnets adjacent in the circumferential direction;
2. The rotor according to claim 1, wherein the fixing member restricts movement of the cover member in the axial direction. The protrusion is
a first projecting portion that abuts against the engaging portion of the cover member;
a second protrusion provided outside the first protrusion in the radial direction and having a shorter protrusion length along the axial direction than the first protrusion;
2. The rotor of claim 1 , comprising: 4. The rotor according to claim 3 , wherein the cover member is fixed to the rotor core by inserting or press-fitting the first protrusion into the mounting hole of the rotor core. The rotor according to any one of claims 1 to 4, wherein the cover member is an elastic member. A rotor according to any one of claims 1 to 5 ;
an annular stator having a plurality of teeth spaced apart on the outer periphery of the rotor and formed radially inward of the rotor core;
a coil wound around the teeth;
with
The motor according to claim 1, wherein the stator faces the rotor on an inner side of the cover member in the axial direction. A brushless wiper motor comprising the motor according to claim 6 for a wiper device of a vehicle.

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