JP2022081087A - Rotor, motor, and rotor assembly method - Google Patents

Abstract

To provide a rotor, a motor, and a rotor assembly method that can suppress deformation of a magnet cover.SOLUTION: A rotor includes a shaft that rotates around an axial center C, a shaft holding hole 72 to hold the shaft, a rotor core 32 rotating around the axial center C in the radial direction, a magnet 33 arranged on the outer peripheral surface of the rotor core 32, and a metal magnet cover 71 that covers the circumference of the magnet 33. The magnet cover 71 includes a cylindrical portion 71a covering the outer circumference of the magnet 33 in the radial direction, and an overhanging portion 71b provided from one end of the cylindrical portion 71a in the axial center C direction to be convex toward the outside in the axial center C direction and to be folded back toward the inside in the radial direction, and also provided over the entire circumference of the cylindrical portion 71a. The overhanging portion 71b is formed with a strength that is less likely to be deformed than the cylindrical portion 71a.SELECTED DRAWING: Figure 4

Description

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

In general, a 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 columnar rotor core fixed to the shaft, and a magnet provided on the rotor core. Then, when the coil is energized, a magnetic attraction force or a repulsive force is generated between the interlinkage magnetic flux formed in the stator and the magnet provided in 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 in order to prevent the magnet from being damaged by foreign matter or the like.

The magnet cover includes a cylindrical portion (outer peripheral surface cover) that covers the outer peripheral surface of the magnet in the radial direction, and an inner flange portion (end surface cover) that projects inward in the radial direction from one axial end of the tubular portion. Have. Further, in order to avoid contact with the corner portion of the magnet, an overhanging portion may be formed at the connecting portion between the tubular portion and the inner flange portion so as to project outward in the axial direction (for example, Patent Document 1). reference). The magnet is held on the outer peripheral surface of the rotor core by such a magnet cover. The magnet cover is fixed to the rotor core and the magnet by, for example, a press-fitting method.

Further, the wall thickness of the magnet cover is related to the size of the clearance between the magnet and the stator. That is, as the wall thickness of the magnet cover becomes thicker, the clearance between the magnet and the stator becomes larger as a result. Since the magnetic flux of the magnet contributes to the rotational force of the rotor, it is desirable that the clearance is as small as possible. That is, it is desirable that the wall thickness of the magnet cover is thin.

Japanese Unexamined Patent Publication No. 2019-187167

However, if the wall thickness of the magnet cover is reduced, the magnet cover is easily deformed by this amount. Under such a configuration, when the magnet cover is assembled by a press-fitting method, for example, when the overhanging portion is pressed with a jig or the like, the overhanging portion may be deformed so as to be crushed. Further, there is a possibility that the tubular portion may be expanded outward in the radial direction due to the deformation of the overhanging portion. In such a case, the magnet cover may not be able to hold the magnet properly.

Therefore, the present invention provides a rotor, a motor, and a method for assembling the rotor that can suppress the deformation of the magnet cover.

In order to solve the above problems, the rotor according to the present invention includes a shaft that rotates around a rotation axis, a rotor core that has a shaft holding hole for holding the shaft, and that rotates about the rotation axis as a radial center. The rotor core includes a magnet arranged on the outer peripheral surface and a metal magnet cover that covers the periphery of the magnet. The magnet cover includes a cylindrical portion that covers the outer peripheral surface of the magnet in the radial direction and the tubular portion. It is provided so as to be convex from one end of the cylindrical portion in the direction of the rotation axis toward the outside in the direction of the rotation axis and to be folded back inward in the radial direction, and to be provided over the entire circumference of the tubular portion. It has an overhanging portion, and the overhanging portion is characterized in that it is formed with a strength that is less likely to be deformed than the tubular portion.

According to the present invention, deformation of the thinned magnet cover can be suppressed.

The perspective view of the motor unit in embodiment of this invention. FIG. 2 is a cross-sectional view taken along the line II-II of FIG. The perspective view of the rotor in embodiment of this invention. FIG. 3 is a cross-sectional view taken along the line IV-IV of FIG. An exploded perspective view of the rotor according to the embodiment of the present invention. The perspective view of the rotor which removed the magnet cover in embodiment of this invention. The plan view which looked at the rotor which removed the magnet cover in embodiment of this invention from the axial direction. The plan view which saw the rotor core in embodiment of this invention from the axial direction. It is a perspective view of the load receiving block in embodiment of this invention, (A) shows the figure which looked at the load receiving block from one end side in the axial direction, (B) is the other end in the axial direction. The figure seen from the side is shown. It is explanatory drawing which shows the assembly method of the magnet cover in embodiment of this invention, and (A) to (C) show each process.

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

<Motor unit>
FIG. 1 is a perspective view of the motor unit 1. FIG. 2 is a cross-sectional view taken along the line II-II of FIG.
The motor unit 1 is used, for example, as a drive source for a wiper device of a vehicle.
As shown in FIGS. 1 and 2, the motor unit 1 includes a motor 2, a deceleration unit 3 that decelerates and outputs the rotation of the motor 2, and a controller 4 that controls drive of the motor 2.
In the following description, the term "axial direction" simply means the direction along the rotation axis direction of the shaft 31 of the motor 2, and the term "circumferential direction" means the circumferential direction of the shaft 31. And. Further, the term "diametrically" simply means the radial direction of the shaft 31.

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

<Motor case>
The motor case 5 is made of a material having excellent heat dissipation such as an aluminum alloy. The motor case 5 includes a first motor case 6 and a second motor case 7 which are configured to be separable in the axial direction. The first motor case 6 and the second motor case 7 are each formed in a bottomed cylindrical shape.
The bottom portion 10 of the first motor case 6 is integrally molded with the gear case 40 of the deceleration portion 3. A through hole 10a through which the shaft 31 of the motor 2 can be inserted is formed at substantially the center of the bottom portion 10 in the radial direction.

Outer flange portions 16 and 17 projecting outward in the radial direction are formed in the openings 6a and 7a of the first motor case 6 and the second motor case 7, respectively. The motor case 5 has an internal space formed by abutting the outer flange portions 16 and 17 against each other. A stator 8 and a rotor 9 are arranged in this internal space. The stator 8 is fixed to the inner peripheral surface of the motor case 5.

<Stator>
The stator 8 includes a stator core 20 made of laminated magnetic steel sheets and the like, and a plurality of coils 24 wound around the stator core 20. The stator core 20 has an annular core main body 21 and a plurality of (for example, six) teeth 22 protruding inward in the radial direction from the inner peripheral portion of the core main body 21. The inner peripheral surface of the core main body 21 and each tooth 22 are covered with a resin insulator 23. The coil 24 is wound around the corresponding predetermined teeth 22 from above the insulator 23. Each coil 24 forms an interlinkage magnetic flux that contributes to the rotation of the rotor 9 by feeding power from the controller 4.

<Deceleration part>
The deceleration unit 3 includes a gear case 40 integrated with the motor case 5 and a worm deceleration mechanism 41 housed in the gear case 40. The gear case 40 is made of a metal material having excellent heat dissipation such as an aluminum alloy. The gear case 40 is formed in a box shape having an opening 40a on one surface. The gear case 40 has a gear accommodating portion 42 that internally accommodates the worm deceleration mechanism 41. Further, on the side wall 40b of the gear case 40, an opening 43 for communicating the through hole 10a of the first motor case 6 and the gear accommodating portion 42 is formed at a position where the first motor case 6 is integrally formed. ..

A bearing boss 49 having a substantially cylindrical shape is formed so as to project from the bottom wall 40c of the gear case 40. The bearing boss 49 is for rotatably supporting the output shaft 48 of the worm reduction mechanism 41, and a slide bearing (not shown) is arranged on the inner peripheral side. An O-ring (not shown) is mounted on the inner peripheral surface of the tip of the bearing boss 49. Further, a plurality of ribs 52 for ensuring rigidity are provided on the outer peripheral surface of the bearing boss 49.

The worm reduction mechanism 41 housed in the gear accommodating portion 42 is composed of a worm shaft 44 integrally formed with the shaft 31 of the rotor 9 and a worm wheel 45 meshed with the worm shaft 44. Both ends of the worm shaft 44 in the axial direction are rotatably supported by the gear case 40 around the rotation axis (axis center C) via bearings 46 and 47. The output shaft 48 of the motor 2 is coaxially and integrally provided on the worm wheel 45. The worm wheel 45 and the output shaft 48 are arranged so that their rotation axes are substantially orthogonal to the rotation axis (axis center C) of the worm shaft 44 (shaft 31 of the motor 2). The output shaft 48 projects to the outside via the bearing boss 49 of the gear case 40. A spline 48a that can be connected to a motor-driven target article is formed at the protruding tip of the output shaft 48.

Further, the worm wheel 45 is provided with a sensor magnet (not shown). The position of this sensor magnet is detected by a magnetic detection element 61, which will be described later, provided in the controller 4. That is, the rotational position of the worm wheel 45 is detected by the magnetic detection element 61 of the controller 4.

<Controller>
The controller 4 has a controller board 62 on which the magnetic detection element 61 is mounted. The controller board 62 is arranged in the opening 40a of the gear case 40 so that the magnetic detection element 61 faces the sensor magnet of the worm wheel 45. The opening 40a of the gear case 40 is closed by the cover 63.

The terminal portions of the plurality of coils 24 drawn out from the stator core 20 are connected to the controller board 62. Further, the terminal of the connector 11 (see FIG. 1) provided on the cover 63 is electrically connected to the controller board 62. In addition to the magnetic detection element 61, the controller board 62 includes a power module (not shown) including a switching element such as a FET (Field Effect Transistor) that controls the drive voltage supplied to the coil 24, and a voltage. A capacitor (not shown) for smoothing is mounted.

<Rotor>
FIG. 3 is a perspective view of the rotor 9. FIG. 4 is a cross-sectional view taken along the line IV-IV of FIG. FIG. 5 is an exploded perspective view of the rotor 9. FIG. 6 is a perspective view of the rotor 9 with the magnet cover 71 removed. FIG. 7 is a plan view of the rotor 9 from which the magnet cover 71 has been removed as viewed from the axial direction. FIG. 8 is a plan view of the rotor core 32 as viewed from the axial direction. FIG. 8 also shows a part of the magnet 33.

As shown in FIGS. 2 to 8, the rotor 9 is rotatably arranged inside the stator 8 in the radial direction via a minute gap. The rotor 9 has a substantially cylindrical rotor core 32 in which a shaft 31 is press-fitted and fixed to the inner peripheral portion and rotates around a rotation axis (axis center C) together with the shaft 31, and four magnets attached to the outer peripheral portion of the rotor core 32. 33, a pair of load receiving blocks 70 arranged at both ends in the axial direction of the rotor core 32, and a metal magnet cover 71 that covers the rotor core 32 and the magnet 33 together with the pair of load receiving blocks 70 from the outside in the axial direction and the radial direction. , Is equipped. The shaft 31 is integrally formed with the worm shaft 44 of the speed reduction unit 3.

The rotor core 32 has a substantially cylindrical core main body portion 32A and four salient poles 32B protruding in the radial direction from the outer peripheral surface of the core main body portion 32A. The rotor core 32 is formed, for example, by pressure-molding soft magnetic powder or laminating a plurality of electrical steel sheets in the axial direction.
The rotor core 32 is formed with a shaft holding hole 72 centered on the axis C (rotational axis) of the rotor 9. The shaft 31 is press-fitted and fixed in the shaft holding hole 72 and held.

Four relief grooves 73 extending radially outward are formed on the inner peripheral surface of the shaft holding hole 72. The relief grooves 73 are arranged at equal intervals in the circumferential direction. Each relief groove 73 is formed so as to extend radially outward when viewed from the axial direction, and communicates with the radial inside of the shaft holding hole 72. Each relief groove 73 is formed over the entire axial direction of the rotor core 32. The radial outer end of each relief groove 73 is an arc-shaped engaging portion 73a. The locking claw 74 (core restricting portion) of the load receiving block 70, which will be described later, is fitted into the engaging portion 73a.

The four salient poles 32B project on the outer periphery of the core main body 32A at equal intervals and extend in the axial direction. The outer peripheral surface of the core main body 32A is formed in a substantially circular shape centered on the axis C (rotational axis) of the rotor 9. The side surface of each salient pole 32B in the circumferential direction is formed flat. A magnet 33 is assembled between the salient poles 32B adjacent to each other in the circumferential direction of the rotor core 32.

As the magnet 33, for example, a ferrite magnet is used. However, the magnet 33 is not limited to this, and a neodymium bond magnet, a neodymium sintered magnet, or the like can be applied.

The magnet 33 is formed in a substantially arc shape when viewed from the axial direction. The inner peripheral surface of the magnet 33 is formed in a substantially arc shape centered on the axis C (rotational axis) of the rotor 9 (a substantially arc shape that substantially matches the outer peripheral surface of the core main body 32A). On the other hand, the outer peripheral surface of the magnet 33 is formed in an arc shape having a radius of curvature smaller than that of the inner peripheral surface. The distance from the axis C (rotation axis) of the rotor 9 to the maximum bulging portion 33c (center in the circumferential direction of the magnet 33, see FIG. 5) on the outer peripheral surface of the magnet 33 and each from the axis C (rotation axis) of the rotor 9. The distance to the radial outer end of the salient pole 32B is approximately the same.

The axial length of each magnet 33 is formed to be longer than the axial length of the salient pole 32B of the rotor core 32. Each magnet 33 is arranged so as to project to one end side and the other end side in the axial direction by substantially the same length with respect to the salient pole 32B in a state of being assembled to the rotor core 32.
At both ends of the magnet 33 in the arc direction, the contact surface 33a that abuts on the flat side surface of the salient pole 32B and the abutting surface 33a are inclined in a direction away from the radial outer end of the contact surface 33a. An extending inclined surface 33b is provided.

The magnet cover 71 has a tubular portion 71a that covers the outer peripheral surfaces of the rotor core 32 and the magnet 33, an overhanging portion 71b integrally molded at one axial end (upper end in FIG. 4) of the tubular portion 71a, and a diameter of the overhanging portion 71b. It includes an inner flange portion 71c integrally molded at the inner end in the direction, and a caulking portion 71d integrally molded at the other end in the axial direction (lower end in FIG. 4) of the tubular portion 71a.

The overhanging portion 71b is formed so as to be convex outward in the axial direction from one end in the axial direction of the tubular portion 71a and to be folded back inward in the radial direction. The overhanging portion 71b is formed over the entire circumference of the tubular portion 71a.
The inner flange portion 71c extends from the folded radial inner end of the overhanging portion 71b. The extending direction of the inner flange portion 71c is along the radial direction.
The caulked portion 71d is formed by being plastically deformed by caulking with the rotor core 32 and the magnet 33 arranged inside the tubular portion 71a together with the pair of load receiving blocks 70. The details of the method of assembling the magnet cover 71 will be described later, and other than the description of this assembling method, the crimped portion 71d of the magnet cover 71 will be described as being crimped.

Here, the overhanging portion 71b is formed with a strength that is less likely to be deformed than the tubular portion 71a, the inner flange portion 71c, and the caulking portion 71d. Examples of the method of increasing the strength of the overhanging portion 71b include a method of hardening the overhanging portion 71b by subjecting it to induction hardening. By adopting such a method, it is possible to make only the overhanging portion 71b having a strength that is less likely to be deformed as compared with other portions.

The deformation means plastic deformation or elastic deformation. Further, it is desirable that the wall thickness of the magnet cover 71 is as thin as possible. This is because the wall thickness of the magnet cover 71 is proportional to the size of the clearance (gap) between the rotor 9 and the stator 8.

9A and 9B are perspective views of the load receiving block 70, FIG. 9A shows a view of the load receiving block 70 from one end side in the axial direction, and FIG. 9B shows the load receiving block 70 in the other direction in the axial direction. The figure seen from the end side is shown.
As shown in FIGS. 5, 6, 9 (A), and 9 (B), the pair of load receiving blocks 70 arranged at both ends in the axial direction of the rotor core 32 have the same configuration. Both are assembled to the rotor core 32 in a state of being turned upside down.

The load receiving block 70 has an annular portion 70A arranged so as to overlap the axial end surface of the core main body portion 32A of the rotor core 32, and an annular portion 70A protruding in the radial direction from the outer peripheral surface of the annular portion 70A in the axial direction of each salient pole 32B of the rotor core 32. A perforated disk-shaped end that is integrally connected to the axially outer sides of the annular portion 70A and the leg portion 70B and is vertically arranged so as to overlap the end faces of the annular portion 70A. It has a part wall 70C and.

The load receiving block 70 is made of, for example, a hard resin. The load receiving block 70 is formed in a shape that substantially overlaps with the rotor core 32 in the axial direction. Each load receiving block 70 is arranged so as to overlap the axial end surface of the rotor core 32, and a part of the radial outer region is arranged between the end surface of the rotor core 32 and the inner flange portion 71c and the caulking portion 71d of the magnet cover 71. Ru. The load receiving block 70 on the caulking portion 71d side receives the caulking load during the caulking operation of the caulking portion 71d.

Four locking claws 74 are integrally molded at equal intervals in the circumferential direction on the inner peripheral edge portion of the annular portion 70A. The locking claw 74 projects toward the rotor core 32 side along the axial direction. The locking claw 74 has a substantially semicircular cross section. The locking claw 74 is fitted into the relief groove 73 (engagement portion 73a) on the inner circumference of the rotor core 32 when the load receiving block 70 is assembled to the end surface of the rotor core 32. By fitting each locking claw 74 into the corresponding relief groove 73 (engaging portion 73a), the load receiving block 70 is restricted from being displaced relative to the rotor core 32 in the radial direction.

The four leg portions 70B are formed so as to project radially outward from the positions corresponding to the locking claws 74 on the outer periphery of the annular portion 70A. The axial thickness of each leg 70B is set to be thicker than the protrusion length of the magnet 33 from the salient pole 32B of the rotor core 32. Therefore, the contact portion of the load receiving block 70 with the inner flange portion 71c (caulking flange) is arranged at a position outside the axial end portion of the magnet 33 in the axial direction. Further, each leg 70B extends radially to the same radial position as the radial end of the corresponding salient pole 32B of the rotor core 32.

The leg portion 70B does not necessarily have to extend to a radial position equal to the radial end of the corresponding salient pole 32B of the rotor core 32. However, it is desirable that at least the salient pole 32B extends to an outer position in the radial direction from the contact region a1 with the magnet 33 (the region in contact with the contact surface 33a, see FIG. 8).
A pair of press-fitting protrusions 76 are formed on the side surface of each leg 70B near the base. Each press-fitting projection 76 extends along the axial direction and is formed so that the bulging height gradually decreases toward the side closer to the rotor core 32.

When the load receiving block 70 is assembled to the rotor core 32 in which the magnet 33 is arranged on the outer peripheral portion, the end portion of each magnet 33 is inserted and arranged between the adjacent leg portions 70B of the load receiving block 70. At this time, the contact surface 33a of the magnet 33 comes into contact with the press-fitting projection 76. As a result, the displacement of the magnet 33 in the circumferential direction is restricted.

The end wall 70C is formed in a disk shape (perforated disk shape) having a radius substantially the same as the length from the axis C of the rotor core 32 to the tip of the leg 70B. The end wall 70C closes the space between the adjacent legs 70B in the circumferential direction at the axially outer position of the legs 70B.
A circular confirmation hole 57 is formed at a position between the adjacent legs 70B on the end wall 70C. The confirmation hole 57 is formed at a position facing the end surface of each magnet 33 in the axial direction. As a result, when the load receiving block 70 is assembled in the magnet cover 71 together with the rotor core 32 holding the magnet 33, the position of each magnet 33 can be visually confirmed from the outside of the rotor core 32. Four confirmation holes 57 are provided so as to have a one-to-one correspondence with each magnet 33.

Further, the end wall 70C has a flat surface on the outer side in the axial direction. On the other hand, as shown in FIG. 9B, a plurality of reinforcing ribs 58 extending in the radial direction are projected on the inner surface of the end wall 70C in the axial direction. Two reinforcing ribs 58 are arranged between the adjacent legs 70B in the circumferential direction of the axially inner surface of the end wall 70C.

The reinforcing rib 58 has a function of suppressing deformation such as dents and waviness in the peripheral region of the end wall 70C when the load receiving block 70 is molded with resin, and the machine of the end wall 70C. It has a function to increase the target strength. Further, the reinforcing rib 58 faces the end face in the axial direction of the magnet 33 when the load receiving block 70 is assembled in the magnet cover 71 together with the rotor core 32 holding the magnet 33. When an excessive load is applied to the magnet 33 in the axial direction, the reinforcing rib 58 abuts on the end surface of the magnet 33 to regulate the axial displacement of the magnet 33.

Further, the annular portion 70A of the load receiving block 70 is formed with a plurality of recesses 59 having a low protrusion height from the end wall 70C. Each recess 59 is arranged between the base ends of the leg portions 70B adjacent to each other in the circumferential direction in the annular portion 70A.

Here, when the load receiving block 70 is assembled in the magnet cover 71, the recess 59 in the axially inner end surface of the portion (the annular portion 70A) shown by inserting dots in FIG. 29 (B) is formed. The area to be removed and the axially inner end face of each leg 70B) come into contact with the core main body 32A of the rotor core 32 and the axial end face of the salient pole 32B. That is, the region of the load receiving block 70 protruding inward in the axial direction is separated into four blocks in the circumferential direction with the recess 59 interposed therebetween. Therefore, it is possible to easily adjust the molding die so that the end face of each block is accurately brought into contact with the end face in the axial direction of the rotor core 32.

<How to assemble the magnet cover>
Next, a method of assembling the magnet cover 71 will be described with reference to FIG.
10A and 10B are explanatory views showing an assembling method of the magnet cover 71, and FIGS. 10A to 10C show each process.
First, before assembling the magnet cover 71, the magnet 33 is arranged in advance on the outer peripheral portion of the rotor core 32, and in this state, the load receiving block 70 is temporarily assembled on each end surface in the axial direction of the rotor core 32. In the following description, this temporarily assembled state will be referred to as a preliminary assembly 79.

In the state of the preliminary assembly 79, as shown in FIG. 10A, the magnet cover 71 is arranged on one end side in the axial direction of the rotor core 32, and the caulking portion 71d is arranged on the rotor core 32 side. At this time, the crimped portion 71d is not crimped, and is formed in a divergent shape so that the opening area increases toward the side opposite to the overhanging portion 71b (rotor core 32 side). The opening 77 of the magnet cover 71 thus formed is arranged toward the rotor core 32 side (cover arrangement step). In this state, the overhanging portion 71b is pressed by the jig 80 from above the overhanging portion 71b.

Then, as shown in FIG. 10B, while pressing the overhanging portion 71b with the jig 80, the magnet cover 71 is pushed into the spare assembly 79 so as to be fitted (cover pushing step). At this time, since the crimped portion 71d is formed in a divergent shape, the magnet cover 71 can be easily fitted to the spare assembly 79.

The magnet cover 71 is pushed until the inner flange portion 71c comes into contact with the end wall 70C of the load receiving block 70. Since the overhanging portion 71b is formed so as to be convex from one end in the axial direction of the tubular portion 71a toward the outward in the axial direction and folded back inward in the radial direction, the corner of the magnet cover 71 receives a load. It is possible to prevent interference with the outer peripheral edge of the block 70 (the outer peripheral edge of the end wall 70C, the radial outer corner portion of the leg portion 70B). Therefore, the inner flange portion 71c can be reliably brought into contact with the end wall 70C of the load receiving block 70.

Here, the overhanging portion 71b is formed with a strength that is less likely to be deformed than the tubular portion 71a, the inner flange portion 71c, and the caulking portion 71d. Therefore, even when the inner flange portion 71c is pushed by the jig 80 until the inner flange portion 71c is brought into contact with the end wall 70C of the load receiving block 70, the overhanging portion 71b is not crushed, whereby the overhanging portion 71b is not crushed. The tubular portion 71a is not pushed outward in the radial direction.

Since the jig 80 is pressed from above the upper end portion of the overhanging portion 71b, a pressing mark 78 formed by being pressed by the jig 80 is formed. The pressing marks 78 are formed over almost the entire circumference of the overhanging portion 71b, and are circular when viewed from the axial direction.
Further, the inner flange portion 71c extends from the folded radial inner end of the overhanging portion 71b. Therefore, when the magnet cover 71 is pushed in until it comes into contact with the end wall 70C of the load receiving block 70, for example, the edge of the radial inner end of the overhanging portion 71b abuts against the end wall 70C, and the end wall 70C is damaged. There is nothing to do.

After the magnet cover 71 is completely pushed into the spare assembly 79, the crimped portion 71d is crimped so as to be folded inward in the radial direction as shown in FIG. 10 (C) (see arrow Y in FIG. 10 (C)). By plastically deforming the caulked portion 71d, the rotor core 32 and the magnet 33 are fixed to the inside of the magnet cover 71 together with the load receiving block 70.

Here, the axially outer end of the load receiving block 70 is covered with a substantially disk-shaped end wall 70C. Therefore, when the load receiving block 70 is inserted into the magnet cover 71 together with the rotor core 32 holding the magnet 33 and the crimped portion 71d of the magnet cover 71 is crimped in that state, the end portion of the magnet cover 71 becomes the end wall 70C. It is caulked and fixed to the end wall 70C so as to cover the entire outer periphery of the magnet.

Further, since the end wall 70C of the load receiving block 70 has a flat surface on the outer side in the axial direction, when the caulking portion 71d is crimped, the caulking load is uniformly applied to the entire outer periphery of the end wall 70C. It works.
Further, the reinforcing rib 58 of the load receiving block 70 suppresses deformation of the outer peripheral edge portion of the end wall 70C of the load receiving block 70 due to the caulking load when the end portion of the magnet cover 71 is crimped.

As described above, the above-mentioned magnet cover 71 has a tubular portion 71a, an inner flange portion 71c, and an overhanging portion 71b formed with a strength that is less likely to be deformed than the caulking portion 71d. By pressing the overhanging portion 71b with the jig 80, the magnet cover 71 is attached to the spare assembly 79. Therefore, even when the magnet cover 71 is formed as thin as possible, the deformation of the magnet cover 71 by the jig 80 can be suppressed when the magnet cover 71 is assembled.

Since the overhanging portion 71b is formed so as to be convex from one end in the axial direction of the tubular portion 71a toward the outward in the axial direction and folded back inward in the radial direction, the corner of the magnet cover 71 receives a load. It is possible to prevent interference with the outer peripheral edge of the block 70 (the outer peripheral edge of the end wall 70C, the radial outer corner portion of the leg portion 70B). Therefore, the inner flange portion 71c can be reliably brought into contact with the end wall 70C of the load receiving block 70.

In order to increase the mechanical strength of the overhanging portion 71b, the overhanging portion 71b is, for example, induction hardened. With this configuration, only a part of the magnet cover 71 (for example, the overhanging portion 71b) can be easily compared with other parts (for example, the tubular portion 71a, the inner flange portion 71c, and the caulking portion 71d). The mechanical strength can be increased.

The inner flange portion 71c extends from the folded radial inner end of the overhanging portion 71b. Therefore, when the magnet cover 71 is pushed in until it comes into contact with the end wall 70C of the load receiving block 70, for example, the edge of the radial inner end of the overhanging portion 71b abuts against the end wall 70C, and the end wall 70C is damaged. It is possible to prevent it from happening.

Further, a pair of load receiving blocks 70 are provided at both ends of the rotor core 32 in the axial direction. The load receiving block 70 has a shape provided between the rotor core 32 and the overhanging portion 71b. With such a configuration, for example, the load applied when crimping the crimped portion 71d is less likely to directly act on the rotor core 32 and the magnet 33. Since the load receiving block 70 receives the load applied when, for example, the caulking portion 71d is crimped, it is possible to prevent the rotor core 32 and the magnet 33 from being damaged by the load due to the caulking.

When assembling the magnet cover 71, the opening 77 of the magnet cover 71 is arranged toward one end side in the axial direction of the rotor core 32 (cover arrangement step). In this state, by pressing the overhanging portion 71b from above the overhanging portion 71b with the jig 80, the magnet cover 71 is pushed into the spare assembly 79 so as to be fitted (cover pushing step). By adopting such a rotor assembly method, deformation of the magnet cover 71 can be reliably suppressed.

The present invention is not limited to the above-described embodiment, and includes various modifications to the above-mentioned embodiment without departing from the spirit of the present invention.

For example, in the above-described embodiment, the case where only the overhanging portion 71b of the magnet cover 71 is formed with a strength that is less likely to be deformed than the tubular portion 71a, the inner flange portion 71c, and the caulking portion 71d has been described. However, the present invention is not limited to this, and the inner flange portion 71c may be formed in addition to the overhanging portion 71b with a strength that is less likely to be deformed than the tubular portion 71a and the caulking portion 71d. In this case, when assembling the magnet cover 71 to the spare assembly 79, either the overhanging portion 71b or the inner flange portion 71c may be pressed by the jig 80. With such a configuration, the same effect as that of the above-described embodiment can be obtained.

In the above-described embodiment, the case where the overhanging portion 71b is subjected to induction hardening, for example, has been described in order to increase the mechanical strength of the overhanging portion 71b. However, the present invention is not limited to this, and various methods can be adopted as long as the overhanging portion 71b can be formed with a strength that is less likely to be deformed than the tubular portion 71a and the caulking portion 71d. For example, the overhanging portion 71b may be formed by using a material having a strength higher than that of the tubular portion 71a, and the overhanging portion 71b may be joined to the tubular portion 71a by welding or the like.

1 ... motor unit, 2 ... motor, 3 ... deceleration unit, 4 ... controller, 5 ... motor case, 6 ... first motor case, 6a, 7a ... opening, 7 ... second motor case, 8 ... stator, 9 ... Rotor, 10 ... bottom, 10a ... through hole, 11 ... connector, 16, 17 ... outer flange, 20 ... stator core, 21 ... core body, 22 ... teeth, 23 ... insulator, 24 ... coil, 31 ... shaft, 32 ... rotor core, 32A ... core body, 32B ... salient pole, 33 ... magnet, 33a ... contact surface, 33b ... inclined surface, 33c ... maximum bulging part, 40 ... gear case, 40a ... opening, 40b ... side wall, 40c ... bottom wall, 41 ... worm reduction mechanism, 42 ... gear housing, 43 ... opening, 44 ... worm shaft, 45 ... worm wheel, 46, 47 ... bearing, 48 ... output shaft, 48a ... spline, 49 ... bearing Boss, 52 ... rib, 57 ... confirmation hole, 58 ... reinforcing rib, 59 ... recess, 61 ... magnetic detection element, 62 ... controller board, 63 ... cover, 70 ... load receiving block, 70A ... annular part, 70B ... leg , 70C ... end wall, 71 ... magnet cover, 71a ... tubular part, 71b ... overhanging part, 71c ... inner flange part, 71d ... caulking part, 72 ... shaft holding hole, 73 ... groove, 73a ... engaging part, 74 ... locking claws, 76 ... press-fitting protrusions, 77 ... openings, 78 ... pressing marks, 79 ... preliminary assembly, 80 ... jigs

Claims (10)

A shaft that rotates around the axis of rotation and
A rotor core having a shaft holding hole for holding the shaft and rotating around the rotation axis in the radial direction.
A magnet arranged on the outer peripheral surface of the rotor core and
A metal magnet cover that covers the circumference of the magnet,
Equipped with
The magnet cover is
A cylindrical portion that covers the outer peripheral surface of the magnet in the radial direction and
It is provided so as to be convex from one end of the tubular portion in the direction of the rotation axis toward the outside in the direction of the rotation axis and to be folded back inward in the radial direction, and to cover the entire circumference of the tubular portion. With the overhanging part provided
Have,
The rotor is characterized in that the overhanging portion is formed with a strength that is less likely to be deformed than the tubular portion. The rotor according to claim 1, wherein the overhanging portion is hardened. The rotor according to claim 1 or 2, wherein the rotor has an inner flange portion extending radially inward from the radial inner end of the overhanging portion. In the rotor according to any one of claims 1 to 3.
A rotor provided between one end of the rotation axis of the rotor core and the overhanging portion, and provided with a load receiving block that abuts on the rotor core and the overhanging portion. The rotor according to any one of claims 1 to 4, wherein the overhanging portion has a jig pressing mark formed by being pressed by a jig from the outside in the direction of the rotation axis. The rotor according to any one of claims 1 to 5,
A stator provided on the radial outer side of the rotor and forming an interlinkage magnetic flux that contributes to the rotation of the rotor.
A motor characterized by being equipped with. A shaft that rotates around the axis of rotation and
A rotor core having a shaft holding hole for holding the shaft and rotating around the rotation axis in the radial direction.
A magnet arranged on the outer peripheral surface of the rotor core and
A metal magnet cover that covers the circumference of the magnet,
Equipped with
The magnet cover is
A cylindrical portion that covers the outer peripheral surface of the magnet in the radial direction and
It is provided so as to be convex from one end of the tubular portion in the direction of the rotation axis toward the outside in the direction of the rotation axis and to be folded back inward in the radial direction, and to cover the entire circumference of the tubular portion. With the overhanging part provided
An inner flange portion extending inward in the radial direction from the radial inner end of the overhanging portion, and an inner flange portion.
Have,
At least the overhanging portion is a method for assembling a rotor which is formed with a strength that is less likely to be deformed than the tubular portion.
A cover arranging step of arranging the magnet cover on the outside of the rotor core in the direction of the rotation axis with the opening on the side opposite to the overhanging portion facing.
A cover pushing step of inserting the tubular portion into the outer peripheral surface of the magnet while pressing the overhanging portion with a jig.
A method of assembling a rotor, which comprises. The method for assembling a rotor according to claim 7, wherein the overhanging portion is quenched. A shaft that rotates around the axis of rotation and
A rotor core having a shaft holding hole for holding the shaft and rotating around the rotation axis in the radial direction.
A magnet arranged on the outer peripheral surface of the rotor core and
A metal magnet cover that covers the circumference of the magnet,
Equipped with
The magnet cover is
A cylindrical portion that covers the outer peripheral surface of the magnet in the radial direction and
It is provided so as to be convex from one end of the tubular portion in the direction of the rotation axis toward the outside in the direction of the rotation axis and to be folded back inward in the radial direction, and to cover the entire circumference of the tubular portion. With the overhanging part provided
An inner flange portion extending inward in the radial direction from the radial inner end of the overhanging portion, and an inner flange portion.
Have,
The overhanging portion and the inner flange portion are a method for assembling a rotor, which is formed with a strength that is less likely to be deformed than the tubular portion.
A cover arranging step of arranging the magnet cover on the outside of the rotor core in the direction of the rotation axis with the opening on the side opposite to the overhanging portion facing.
A cover pushing step of inserting the cylindrical portion into the outer peripheral surface of the magnet while pressing either the overhanging portion or the inner flange portion with a jig.
A method of assembling a rotor, which comprises. The method for assembling a rotor according to claim 9, wherein the overhanging portion and the inner flange portion are quenched.

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