Rotor and motor

Abstract

To provide a rotor that, regardless of the curvature deformation of a leading end of a salient pole part of a core plate, can easily and stably assemble the rotor core and a load receiving block inside a magnet cover, and a motor.SOLUTION: A rotor comprises a rotor core 32, permanent magnets 33, a magnet cover 71, and a load receiving block 70. The rotor core has a core main body part and a plurality of salient poles. The permanent magnets are arranged between the salient poles 32B. The magnet cover covers the outside of the rotor core and the permanent magnets, and has flange parts at the axial outside ends. The load receiving block is arranged between an axial end of the rotor core and the flange part. The rotor core is formed by laminating a plurality of core plates. A spacer part is arranged at the axial end of the rotor core. The spacer part forms a gap spaced in the axial direction between axial outside ends of the salient poles and an opposing surface of the load receiving block.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a rotor and a motor. [Background technology]

[0002] Some motors used in vehicle wiper devices and the like have permanent magnets provided on the rotor side. A known arrangement of the permanent magnets on the rotor used in this type of motor is a surface permanent magnet (SPM) arrangement in which the permanent magnets are arranged on the outer periphery of the rotor core.

[0003] In rotors that use this method, multiple permanent magnets are assembled to the outer periphery of a rotor core, and the outside of the rotor core and permanent magnets are covered in a roughly cylindrical magnet cover. After the rotor core and permanent magnets are placed inside the roughly cylindrical peripheral wall, the axial end of the magnet cover (the direction along the rotation axis) is fixed to the end of the rotor core by crimping.

[0004] However, in a rotor in which the magnet cover is fixed to the rotor core by crimping, a large crimping load is easily transmitted to the permanent magnet when the edge of the magnet cover is crimped. If a large crimping load is transmitted to the permanent magnet through the crimped portion of the magnet cover during the crimping operation, there is a concern that the permanent magnet may be damaged or deteriorated.

[0005] As a countermeasure to this, a rotor structure has been proposed in which a separate load-receiving block is disposed between the flange portion for locking the magnet cover and the axially outer end of the rotor core (see, for example, Patent Document 1). According to this rotor, the clamping load acting on the flange portion is received by the load-receiving block, so that a large clamping load is unlikely to be transmitted to the permanent magnets arranged on the outer periphery of the rotor core. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2020 / 105479 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in many of the above-mentioned types of rotors, the rotor core is formed by stacking multiple core plates in the axial direction. The rotor core has a substantially cylindrical core body and multiple salient poles protruding in the radial direction from the outer periphery of the core body, with permanent magnets disposed between each of the salient poles adjacent in the circumferential direction. When manufacturing a rotor core, multiple plate materials for the core plate are prepared by stacking them, and the multiple plate materials are pressed to punch out the core plates at once. At this time, since the salient poles of the core plate protrude radially from the core body with a narrow width, a large bending load acts on the tip end of the salient poles. Therefore, the press-formed core plate is prone to warping deformation toward the tip end of the salient poles in the punching direction.

[0008] When the multiple core plates formed as described above are used as a rotor core in a stacked state, and the rotor core is housed in a magnet cover together with multiple permanent magnets and a load-receiving block, the tip portion (the tip portion of the warp) of the salient pole portion of the core plate located at the axially outer end abuts against the load-receiving block. At this time, the tip portion of the salient pole portion of the core plate pushes back the load-receiving block in a direction against the crimping load (axially outward), making the crimping work difficult and making the fixation of the rotor core by crimping unstable.

[0009] Therefore, the present invention aims to provide a rotor and motor in which the rotor core and load-receiving block can be easily and stably assembled within the magnet cover regardless of warping deformation of the tips of the salient pole portions of the core plate. [Means for solving the problem]

[0010] In order to solve the above problems, the rotor according to the present invention employs the following configuration. That is, the rotor of the present invention comprises a rotor core having a substantially cylindrical core body portion and a plurality of salient poles protruding radially from the outer periphery of the core body portion, a plurality of permanent magnets arranged between adjacent salient poles in the circumferential direction of the rotor core, an approximately cylindrical magnet cover covering the outside of the rotor core and the plurality of permanent magnets and having a flange portion bent radially inward at its axially outer end, and a load-receiving block arranged between the axially outer end of the rotor core and the flange portion and capable of transmitting axial loads between the flange portion and the rotor core, wherein the rotor core is constructed by stacking a plurality of core plates made of a magnetic material in the axial direction, and a spacer portion is arranged on at least one axially outer end side of the rotor core to form a gap in the axial direction between the axially outer end face of the salient pole and the opposing face of the load-receiving block that faces the end face. Effect of the Invention

[0011] According to the rotor of the present invention, a gap is formed between the axial end faces of the salient poles of the rotor core and the opposing face of the load-receiving block to accommodate the warping of the tips of the salient poles. Therefore, when the rotor of the present invention is used, the rotor core and the load-receiving block can be easily and stably assembled inside the magnet cover, regardless of the warping deformation of the tips of the salient poles of the core plate. [Brief description of the drawings]

[0012] [Figure 1] FIG. 2 is a perspective view of a motor unit according to the embodiment. [Diagram 2] 2 is a cross-sectional view of the motor unit according to the embodiment taken along line II-II in FIG. [Diagram 3] FIG. 2 is an exploded perspective view of the rotor according to the embodiment. [Figure 4] 1 is a cross-sectional view taken along an axial direction of a rotor according to an embodiment of the present invention; [Diagram 5]FIG. 2 is a perspective view of a rotor core according to the embodiment. [Figure 6] FIG. 2 is a perspective view of a first core plate of the embodiment. [Figure 7] FIG. 4 is a perspective view of a second core plate of the embodiment. [Figure 8] FIG. 4 is a plan view of a first core plate of the embodiment. [Figure 9] FIG. 4 is a plan view of a second core plate of the embodiment. [Figure 10] 5 is a cross-sectional view similar to FIG. 4 of the rotor according to the embodiment before a crimping step. [Figure 11] 11 is an enlarged view of a portion XI in FIG. 10 according to the embodiment. [Figure 12] FIG. 11 is a plan view of the first core plate and the second core plate of the first alternative embodiment overlapping each other. [Figure 13] FIG. 11 is a side view of a rotor core according to another embodiment 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the embodiments described below, the same parts are denoted by the same reference numerals, and duplicated descriptions will be omitted.

[0014] (Motor unit) Fig. 1 is a perspective view of a motor unit 1 used in a vehicle. Fig. 2 is a cross-sectional view of the motor unit 1 taken along line II-II in Fig. 1. The motor unit 1 is used, for example, as a drive source for a wiper device of a vehicle. As shown in Figures 1 and 2, the motor unit 1 includes a motor 2, a speed reducer 3 that reduces the rotation speed of the motor 2 and outputs the reduced speed, and a controller 4 that controls the drive of the motor 2. In the following description, the term "axial direction" refers to the direction along the rotation axis of the rotating shaft 31 of the motor 2, and the term "circumferential direction" refers to the circumferential direction of the rotating shaft 31. Additionally, the term "radial direction" refers to the radial direction of the rotating shaft 31.

[0015] (Motor) The motor 2 includes a motor case 5, a substantially cylindrical stator 8 housed in the motor case 5, and a rotor 9 disposed radially inside the stator 8 and rotatable relative to the stator 8. The motor 2 of this embodiment is a so-called brushless motor that does not require brushes to supply power to the stator 8.

[0016] (Motor case) The motor case 5 is made of a material with excellent heat dissipation properties, such as an aluminum alloy. The motor case 5 is made up of 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 cylindrical shape with a bottom. The first motor case 6 is molded integrally with the gear case 40 so that the bottom 10 is connected to the gear case 40 of the reduction unit 3. A through hole through which the rotating shaft 31 of the motor 2 can be inserted is formed in approximately the center in the radial direction of the bottom 10.

[0017] Further, outer flange portions 16, 17 that protrude radially outward are formed at the openings 6a, 7a of the first motor case 6 and the second motor case 7, respectively. In the motor case 5, the outer flange portions 16, 17 are butted against each other to form an internal space. A stator 8 and a rotor 9 are disposed in the internal space of the motor case 5. The stator 8 is fixed to the inner peripheral surface of the motor case 5.

[0018] (Stator) The stator 8 includes a stator core 20 made of laminated electromagnetic steel sheets or the like, and a plurality of coils 24 wound around the stator core 20. The stator core 20 includes an annular core body 21 and a plurality of (e.g., six) teeth 22 protruding radially inward from an inner periphery of the core body 21. The inner periphery of the core body 21 and each of the teeth 22 are covered with a resin insulator 23. The coils 24 are wound around corresponding predetermined teeth 22 from above the insulator 23. Each coil 24 generates a magnetic field for rotating the rotor 9 when power is supplied from the controller 4.

[0019] The rotor 9 is rotatably disposed on the radial inside of the stator 8 via a small gap. The rotor 9 includes a substantially cylindrical rotor core 32, into whose inner periphery the rotating shaft 31 is press-fitted, and four permanent magnets 33 (see FIG. 3) assembled to the outer periphery of the rotor core 32. In this embodiment, the rotating shaft 31 is integrally formed with a worm shaft 44 constituting the reduction unit 3. The rotating shaft 31 and the worm shaft 44 are rotatably supported by the motor case 5 and the gear case 40. The rotating shaft 31 and the worm shaft 44 rotate around the rotation axis (axis center C). For example, a ferrite magnet is used as the permanent magnet 33. However, the permanent magnet 33 is not limited thereto, and neodymium bonded magnets, neodymium sintered magnets, etc. may also be used. The detailed structure of the rotor 9 will be described later.

[0020] (Deceleration part) The reduction unit 3 includes a gear case 40 integrated with the motor case 5, and a worm reduction mechanism 41 housed in the gear case 40. The gear case 40 is made of a metal material with excellent heat dissipation properties, such as an aluminum alloy. The gear case 40 is formed in a box shape with an opening 40a on one side. The gear case 40 has a gear housing section 42 that houses the worm reduction mechanism 41 therein. In addition, an opening 43 that communicates with the through hole of the first motor case 6 and the gear housing section 42 is formed in the side wall 40b of the gear case 40 at a location where the first motor case 6 is integrally formed.

[0021] A generally cylindrical bearing boss 49 protrudes from the bottom wall 40c of the gear case 40. The bearing boss 49 rotatably supports the output shaft 48 of the worm reduction mechanism 41, and a plain bearing (not shown) is disposed on the inner periphery of the bearing boss 49. An O-ring (not shown) is attached to the inside of the tip of the bearing boss 49. In addition, a plurality of ribs 52 protrude from the outer periphery of the bearing boss 49 to ensure rigidity.

[0022] The worm reduction mechanism 41 housed in the gear housing 42 is composed of a worm shaft 44 and a worm wheel 45 meshed with the worm shaft 44. The worm shaft 44 is rotatably supported at both axial ends by the gear case 40 via bearings 46 and 47. The worm wheel 45 is coaxially and integrally provided with an output shaft 48 of the motor 2. The worm wheel 45 and the output shaft 48 are arranged such that their rotation axes are substantially perpendicular to the rotation axis (axis center C) of the worm shaft 44 (rotation shaft 31 of the motor 2). The output shaft 48 protrudes to the outside through a bearing boss 49 of the gear case 40. A spline 48a that can be connected to an object to be driven by the motor is formed at the protruding tip of the output shaft 48.

[0023] In addition, a sensor magnet (not shown) is provided on the worm wheel 45. The position of this sensor magnet is detected by a magnetic detection element 61 provided in the controller 4 (described later). In other words, the rotational position of the worm wheel 45 is detected by the magnetic detection element 61 of the controller 4.

[0024] (controller) The controller 4 has a controller board 62 on which a magnetic detection element 61 is mounted. The controller board 62 is disposed 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 a cover 63.

[0025] Terminal portions of the multiple coils 24 drawn out from the stator core 20 are connected to the controller board 62. In addition, a terminal of a connector 11 (see FIG. 1) provided on a cover 63 is electrically connected to the controller board 62. In addition to the magnetic detection element 61, the controller board 62 also has mounted thereon a power module (not shown) made up of switching elements such as FETs (Field Effect Transistors) that control the drive voltage supplied to the coils 24, a capacitor (not shown) that smoothes the voltage, and the like.

[0026] (Detailed structure of rotor) Fig. 3 is an exploded perspective view of rotor 9 of this embodiment, and Fig. 4 is a cross-sectional view along the axial direction of rotor 9 (along axis C). In Fig. 4, rotor 9 is cross-sectionally taken along two salient poles 32B arranged at opposite positions around axis C of rotor core 32, which will be described later. In this specification, the term "axial direction" in relation to rotor 9 means a direction along the rotation axis (axis C), and the term "radial direction" means a direction perpendicular to the rotation axis. As shown in Figures 3 and 4, the rotor 9 includes a rotor core 32 that can rotate around the rotation axis (axis center C) together with the rotation shaft 31 (see Figure 2), four permanent magnets 33 arranged on the outer periphery of the rotor core 32, a pair of load-receiving blocks 70 arranged on one end side and the other end side of the axial direction of the rotor core 32, and a metal magnet cover 71 that covers the rotor core 32 and the permanent magnets 33 together with the pair of load-receiving blocks 70 from the axial and radial outside.

[0027] The rotor core 32 has a substantially cylindrical core body 32A and four salient poles 32B protruding in the radial direction from the outer circumferential surface of the core body 32A. In this embodiment, the radial protruding length of each salient pole 32B is longer than the radial width (maximum radial width) of the core body 32A. The rotor core 32 is configured by stacking multiple core plates made of magnetic material such as electromagnetic steel sheets in the axial direction. The core plates are made of multiple first core plates 80 of the same shape and one second core plate 81 of a slightly different shape from the first core plate 80. The second core plate 81 is overlaid on one axial end face of the first core plates 80 which are stacked in the axial direction. The detailed structures of the first core plate 80 and the second core plate 81 will be described later.

[0028] The four salient poles 32B of the rotor core 32 protrude at equal intervals in the radial direction from the outer periphery of the core body 32A, and the protruding portions extend along the axial direction. In this embodiment, the outer periphery of the core body 32A is formed in a substantially circular shape centered on the axis C (axis of rotation) of the rotor 9. Of the salient poles 32B, the side surfaces facing the circumferential direction of the rotor core 32 are formed by flat surfaces. Permanent magnets 33 are arranged between the salient poles 32B adjacent to each other in the circumferential direction of the rotor core 32.

[0029] In this embodiment, the permanent magnet 33 is formed in a substantially arc shape when viewed in the axial direction. The distance from the axis C of the rotor 9 to the radially outer end of each salient pole 32B of the rotor core 32 is set to be substantially the same as the distance from the axis C of the rotor 9 to the maximum bulge of the outer circumferential surface of the permanent magnet 33.

[0030] The axial length of each permanent magnet 33 is formed to be longer than the axial length of the salient pole 32B of the rotor core 32. In the present embodiment, each permanent magnet 33, when assembled to the rotor core 32, is set to protrude by approximately the same length on one end side and the other end side in the axial direction from the salient pole 32B.

[0031] The inner peripheral surface of the rotor core 32 is formed with four arcuate surfaces centered on the axis C of the rotor 9, and escape grooves 73 extending radially outward from between adjacent arcuate surfaces. Each escape groove 73 extends radially outward by the same length, and the end in the extending direction is an arcuate engaging portion 73a. A locking claw 74 of a load-receiving block 70, which will be described later, is fitted into the engaging portion 73a of each escape groove 73. The rotating shaft 31 of the motor 2 (see FIG. 2) is press-fitted and fixed into the four arcuate surfaces on the inner peripheral surface of the rotor core 32.

[0032] The magnet cover 71 has a cylindrical peripheral wall 71a and a pair of flanges 71b, 71c that bend and extend radially inward from one end and the other end of the peripheral wall 71a in the axial direction. The rotor core 32 and the permanent magnets 33 are arranged inside the peripheral wall 71a together with a pair of load receiving blocks 70. At least one of the pair of flanges 71b, 71c is a crimped flange that is plastically deformed by crimping in a state in which the rotor core 32 and the permanent magnets 33 are arranged inside the peripheral wall 71a together with the pair of load receiving blocks 70. In the following description, it is assumed that one flange 71b is bent and formed in advance, and the other flange 71c is formed by crimping after the rotor core 32 and the like are loaded.

[0033] The load receiving blocks 70 arranged on one and the other axial ends of the rotor core 32 have the same shape. The two load receiving blocks 70 are assembled to the rotor core 32 in an inverted upside down state. The load receiving blocks 70 are formed from, for example, a hard resin. The load receiving blocks 70 are formed in a shape that substantially overlaps with the rotor core 32 and the permanent magnets 33 when viewed in the axial direction.

[0034] The load-receiving block 70 has an annular portion 70A arranged overlapping the axial end face of the core body portion 32A of the rotor core 32, four leg portions 70B protruding radially from the outer circumferential surface of the annular portion 70A and arranged to face the axial end faces of each salient pole 32B of the rotor core 32, and a perforated, disc-shaped end wall 70C integrally formed axially outside the annular portion 70A and the leg portions 70B and extending radially outward from the annular portion 70A.

[0035] The four legs 70B are formed so as to overlap with the respective salient poles 32B of the rotor core 32 when viewed in the axial direction of the rotor 9. The circumferential width of each leg 70B is set to be substantially the same as the circumferential width of the salient pole 32B. The axial end face of each leg 70B facing the rotor core 32 is defined as an opposing surface 70Ba that faces the end face (axially outer end face) of the salient pole 32B on the rotor core 32 side. The opposing surface 70Ba of each leg 70B of one load receiving block 70 (the lower load receiving block in Figs. 3 and 4) is overlapped with the end face of the salient pole 32B at one end of the rotor core 32 in the axial direction. In contrast, the opposing surface 70Ba of each leg 70B of the other load receiving block 70 (the upper load receiving block in Figs. 3 and 4) faces the end face of the salient pole 32B at the other end of the rotor core 32 in the axial direction with a gap therebetween without abutting against it.

[0036] The end wall 70C is formed in a disk shape (a disk shape with a hole) with an outer diameter substantially equal to the length from the axis C of the rotor core 32 to the tip of the leg portion 270B. The end wall 70C closes the space between the circumferentially adjacent leg portions 70B at an axially outer position of the leg portions 70B.

[0037] When the flange portion 71c of the magnet cover 71 is crimped while being housed in the magnet cover 71 together with the rotor core 32, each load-receiving block 70 receives a crimping load in the axial direction from the flange portions 71b, 71c. At this time, each load-receiving block 70 abuts against the flange portions 71b, 71c and the rotor core 32, and transmits the axial load (crimping load) between the flange portions 71b, 71c and the rotor core 32.

[0038] The axial thickness of each leg 70B of the load receiving block 70 is set to be thicker than the protruding length of the permanent magnet 33 from the salient pole 32B of the rotor core 32. Therefore, when the load receiving block 70 is assembled to the axial end of the rotor core 32, the end of the permanent magnet 33 protruding from the axial end of the rotor core 32 is received between the adjacent legs 70B of the load receiving block 70. In addition, in this embodiment, each leg 70B extends radially to a position equal to the radial end of the corresponding salient pole 32B of the rotor core 32. When the load receiving block 70 is assembled at one axial end of the rotor core 32 (the lower end in FIGS. 3 and 4), the annular portion 70A and each leg portion 70B of the load receiving block 70 come into contact with the end faces of the core body portion 32A and each salient pole 32B of the rotor core 32. When the load receiving block 70 is assembled at the other axial end of the rotor core 32 (the upper end in FIGS. 3 and 4), the annular portion 70A of the load receiving block 70 comes into contact with the end face of the core body portion 32A of the rotor core 32.

[0039] A locking claw 74 that protrudes approximately along the axial direction toward the rotor core 32 is formed integrally with the inner peripheral edge of the annular portion 70A of each load receiving block 70 at a position extending radially inward from each leg portion 70B. The locking claw 74 has a substantially semicircular cross section and is adapted to fit into an escape 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 face of the rotor core 32. The load receiving block 70 is positioned radially and circumferentially with respect to the rotor core 32 by fitting each locking claw 74 into the corresponding escape groove 73 (engagement portion 73a).

[0040] (Detailed structure of the core plate) Fig. 5 is a perspective view of rotor core 32 in which first core plate 80 and second core plate 81 are laminated. Figs. 6 and 7 are perspective views of each of first core plate 80 and second core plate 81, and Figs. 8 and 9 are plan views of each of first core plate 80 and second core plate 81. As shown in FIG. 6 and FIG. 8, the first core plate 80 has an annular base portion 80a constituting the core body portion 32A of the rotor core 32, and a plurality of salient pole pieces 80b (salient pole portions) constituting the salient poles 32B of the rotor core 32. The salient pole pieces 80b extend radially outward from the outer periphery of the base portion 80a. The above-mentioned plurality of escape grooves 73 are formed on the inner periphery side of the base portion 80a. A boss portion 53 is provided between each of the escape grooves 73 adjacent to each other in the circumferential direction of the base portion 80a. The boss portion 53 is formed into a cylindrical shape with a bottom by press molding or the like so as to bulge in one axial direction of the first core plate 80. The first core plates 80 are fixed to each other by fitting the convex side of the boss portion 53 of the first core plate 80 of the lower layer into the concave side of the boss portion 53 of the first core plate 80 of the upper layer.

[0041] When forming the first core plate 80, bosses 53 are formed in advance on a plurality of plate materials. From this state, the bosses 53 of the upper and lower plate materials are fitted together, and the plurality of plate materials are stacked. After this, the stacked plurality of plate materials are punched by a press, and the contours of the plurality of first core plates 80 are formed simultaneously. At this time, since the salient pole piece 80b of the first core plate 80 formed by punching with a press is narrow in width and extends long in the radial direction, warping deformation (see Figure 11) along the punching direction is likely to occur at the tip side of the salient pole piece 80b.

[0042] If a boss similar to the boss 53 of the base 80a is formed in advance on each salient pole piece 80b and the salient pole pieces 80b of the stacked first core plates 80 are fixed to each other by the projection-recess fit of the boss, the warpage of the salient pole pieces 80b can be suppressed to some extent. However, in reality, if a boss is formed on a narrow salient pole piece 80b, the magnetic resistance of the salient pole 32B of the rotor core 32 increases. For this reason, it may not be possible to form a boss on the salient pole piece 80b, and it is difficult to eliminate the warpage that occurs at the tip of the salient pole piece 80b during punching by a press.

[0043] The second core plate 81 is formed in an annular shape as shown in Figs. 7 and 9. The second core plate 81 is formed in approximately the same shape and size as the base portion 80a of the first core plate 80. The second core plate 81 is made of a plate material having the same thickness as the first core plate 80. The second core plate 81 constitutes a part of the core body portion 32A of the rotor core 32. The second core plate 81 is disposed overlapping one of the axial ends of the laminate of the first core plate 80, the end on which the tip of the salient pole piece 80b is warped and deformed when punched out by a press.

[0044] A plurality of clearance grooves 73 are formed on the inner circumferential side of the second core plate, similar to the base portion 80a of the first core plate 80. Circular through holes 54 are formed between adjacent clearance grooves 73 in the circumferential direction of the second core plate. The through holes 54 are formed at positions corresponding to the boss portions 53 of the first core plate 80. The inner diameter of the through holes 54 is formed to be substantially the same as the outer diameter of the boss portions 53. The boss portions 53 of the first core plate 80 at the end portions are fitted into the through holes 54. As a result, the second core plate 81 is fixed to the first core plate 80 at the end portions, and the assembly of the rotor core 32 is completed.

[0045] (Rotor assembly) Fig. 10 is a cross-sectional view showing a state in which load receiving blocks 70 are assembled to both axial ends of rotor core 32, and rotor core 32 and load receiving blocks 70 are housed inside magnet cover 71. In Fig. 10, flange portion 71b is bent only at one end (lower end in the figure) of magnet cover 71, but flange portion 71c on the other end side of magnet cover 71 is not bent. Flange portion 71 on the other end side will be bent in a later crimping process. Fig. 11 is an enlarged view of portion XI in Fig. 10. As shown in Figs. 10 and 11, when the load receiving block 70 is assembled to the end of the rotor core 32 on the side where the second core plate 81 is arranged, the axial end face of the annular portion 70A of the load receiving block 70 abuts against the end face of the second core plate 81. At this time, the opposing faces 70Ba (end faces) of the legs 70B of the load receiving block 70 face the salient pole pieces 80b of the first core plate 80 at the end with an axial gap d therebetween. The warped portion of the tip of the salient pole piece 80b is received in the gap d between the salient pole piece 80b and the opposing face 70Ba. The gap d between the salient pole piece 80b and the opposing face 70Ba is dimensioned so that the warped portion of the tip of the salient pole piece 80b does not abut against the opposing face 70Ba. When the warped portion of the tip of the salient pole piece 80b abuts against the opposing face 70Ba, a plurality of second core plates 81 may be used in a stacked manner. In this embodiment, the second core plate 81 arranged at the end of the rotor core 32 constitutes a spacer portion that forms an axial gap d between the axial end face of the salient pole 32B and the opposing surface 70Ba of the load-receiving block 70.

[0046] (Magnetic cover 71 crimping) 10 and 11, when the flange portion 71c on the other end side of the magnet cover 71 is crimped, the flange portion 71c is bent radially inward and the crimping load is transmitted from the flange portion 71c to the rotor core 32 via the load receiving blocks 70. As a result, the rotor core 32 is fixed inside the magnet cover 71 together with the two load receiving blocks 70. At this time, because the load receiving blocks 70 are interposed between the two flange portions 71b, 71c and each end face of the rotor core 32, the crimping load does not act on the permanent magnets 33 arranged on the outer periphery of the rotor core 32. As a result, damage and deterioration of the permanent magnets 33 are prevented in advance.

[0047] (Effects of the embodiment) As described above, in the rotor 9 of this embodiment, the second core plate 81, which is a spacer, is arranged at the axial end of the rotor core 32 so as to form a gap d between the end face of the salient pole 32B (salient pole piece 80b) and the opposing surface 70Ba of the load receiving block 70. Therefore, even if warpage deformation occurs in the tip of the salient pole piece 80b (salient pole portion) of the first core plate 80 along the punching direction when the first core plate 80 is punched, the above-mentioned gap d created by the second core plate 81 can accommodate the warpage of the tip of the salient pole piece 80b. Therefore, when the rotor core 32 and the load receiving block 70 are assembled in the magnet cover 71, it is possible to prevent the warpage of the salient pole piece 80b at the end of the rotor core 32 from coming into contact with the load receiving block 70 and pushing back the load receiving block 70.

[0048] Therefore, when the rotor 9 of this embodiment is adopted, the rotor core 32 and the load-receiving block 70 can be easily and stably assembled within the magnet cover 71, regardless of warping deformation of the tip of the salient pole piece 80b (salient pole portion) of the first core plate 80. As a result, the rotor 9 can be manufactured more easily and the product quality of the rotor 9 can be improved. This reduces the energy consumption when manufacturing the rotor 9 and improves the performance of the motor 2 that uses the rotor 9. This makes it possible to contribute to Goal 7 of the Sustainable Development Goals (SDGs) led by the United Nations, which is to "Ensure access to affordable, reliable, sustainable and modern energy for all."

[0049] In addition, in the rotor 9 of this embodiment, the second core plate 81, which is a spacer portion, is formed in a disk shape having approximately the same diameter as the base portion 80a (core body portion) of the first core plate 80. This makes it easier to manufacture the second core plate 81, and also improves the yield. Furthermore, since the second core plate 81 of this configuration does not have a salient pole piece (salient pole portion) that protrudes radially outward, it is easier to handle during assembly.

[0050] Furthermore, the rotor 9 of this embodiment employs the second core plate 81 made of a magnetic material as a spacer portion for creating an axial gap d between the salient pole piece 80b on the rotor core 32 side and the opposing surface 70Ba of the load-receiving block 70, thereby increasing the effective magnetic flux flowing through the rotor core 32. Therefore, when this configuration is employed, the rotation performance of the motor 2 can be improved. Furthermore, in the rotor 9 of this embodiment, the second core plate 81 does not have any salient pole pieces that protrude radially outward, which reduces the weight of the rotor core 32 and therefore the weight of the entire rotor 9. Therefore, when this configuration is adopted, the inertia force of the rotor 9 can be reduced and the controllability of the motor 2 can be improved.

[0051] Furthermore, in the rotor 9 of this embodiment, the second core plate 81, which is the spacer portion, is made of a plate material having the same thickness as the other core plate (first core plate 80) of the rotor core 32. Therefore, when this configuration is adopted, the first core plate 80 and the second core plate 81 can be efficiently punched out from the same plate material, and production costs can be reduced.

[0052] Furthermore, in the rotor 9 of this embodiment, adjacent core plates in the stacking direction (adjacent first core plates 80, and adjacent first core plates 80 and second core plates 81) are fixed in portions (such as the base portions 80a) other than the salient poles 32B by recess-projection fitting using the boss portions 53 and through holes 54. In this type of rotor 9, warping deformation usually occurs inevitably on the tip side of the salient poles 32B (salient pole pieces 80b) where the core plates are not fixed to each other when punching out the core plates. For this reason, the configuration of this embodiment, in which the gap d formed between the salient poles 32B of the rotor core 32 and the opposing surface 70Ba of the load-receiving block 70 accommodates the warping of the tip of the salient poles 32B (salient pole pieces 80b), is particularly effective.

[0053] Furthermore, in the rotor 9 of this embodiment, the radial protruding length of the salient pole 32B of the rotor core 32 is longer than the radial width (width in the radial direction) of the core body 32A. In the case of this type of rotor 9, the protruding length of the salient pole piece 80b of the first core plate 80 becomes long, and warping deformation is likely to occur on the tip side of the salient pole piece 80b when the first core plate 80 is punched out. For this reason, the configuration of this embodiment, in which the gap d formed between the salient pole 32B of the rotor core 32 and the opposing surface 70Ba of the load-receiving block 70 accommodates the warping of the tip of the salient pole 32B (salient pole piece 80b), is particularly effective.

[0054] (Another embodiment 1) FIG. 12 is a plan view showing a first core plate 80 and a second core plate 181 of a rotor core 132 according to the first alternative embodiment superimposed on each other. The rotor of this embodiment has a basic configuration similar to that of the above embodiment, but the shape of the second core plate 181 is slightly different from that of the above embodiment.

[0055] That is, the second core plate 181 has an annular portion 181a having substantially the same outer diameter as the base (core body) of the first core plate 80, and a plurality of claw portions 181b projecting radially from the annular portion 181a and overlapping with the roots of the salient pole pieces 80b (salient poles 32B) of the first core plate 80. Each of the claw portions 181b of the second core plate 181 is disposed at a position corresponding to each of the salient poles 32B of the rotor core 132, and is formed to have substantially the same width as each of the salient poles 32B. The protruding length (protruding length in the radial direction) of each of the claw portions 181b is set to be shorter than 1 / 2 the protruding length of the salient poles 32B of the rotor core 132. This makes it possible to suppress warping and deformation of each of the claw portions 181b when the second core plate 181 is press-molded.

[0056] In the second core plate 181 of this embodiment, the claw portion 181b that overlaps with the root portion of the salient pole piece 80b of the first core plate 80 protrudes from the annular portion 181a, but the claw portion 181b is long enough not to overlap with the tip side of the salient pole piece 80b. Therefore, when the rotor core 132 is assembled into the magnet cover together with the load receiving block, even if the tip of the salient pole piece 80b of the first core plate 80 at the end is warped, the warped portion is accommodated by an axial gap (a gap between the opposing surfaces of the salient pole and the load receiving block) that is formed radially outward of the claw portion 181b of the second core plate 181. Therefore, in the rotor of this embodiment as well, regardless of warpage and deformation of the tips of the salient pole pieces 80b of the first core plate 80, the rotor core 132 and the load receiving blocks can be easily and stably assembled inside the magnet cover.

[0057] Furthermore, in the rotor of this embodiment, when a crimping load is input from the load receiving block to the second core plate 181 during assembly, the crimping load acts to suppress warpage deformation of the salient pole piece 80b of the first core plate 80 through the claw portion 181b of the second core plate 181. Therefore, when this configuration is adopted, it becomes possible to more easily and stably assemble the rotor core 132 and the load receiving block inside the magnet cover.

[0058] (Another embodiment 2) FIG. 13 is a side view of a rotor core 232 according to the second alternative embodiment. The rotor of this embodiment has a basic configuration similar to that of the above-described embodiment shown in Figures 1 to 11, but differs from the above-described embodiment in that second core plates 81 are disposed on both axial sides of stacked first core plates 80. In order to distinguish between the two second core plates 81, in Figure 13, one second core plate is labeled with reference numeral 81A and the other second core plate is labeled with reference numeral 81B.

[0059] The second core plate 81A arranged at one axial end of the stacked first core plates 80 has a plurality of through holes (not shown) into which the convex portions of the bosses of the first core plates 80 are fitted, as in the embodiment shown in Figs. 1 to 11. In contrast, the second core plate 81B arranged at the other axial end has a boss portion that is fitted into the concave portion of the boss of the first core plate 80 adjacent in the stacking direction. One second core plate 81A is fixed to one axial end of the stacked first core plates 80, and the other second core plate 81B is fixed to the other axial end.

[0060] When the two load receiving plates are assembled to the rotor core 232 configured in this manner, each of the second core plates 81A, 81B of the rotor core 232 abuts against the annular portion (the radially inner edge) of the corresponding load receiving block. This forms an axial gap between the opposing surface of each load receiving block and the end of the salient pole 32B (salient pole piece 80b) of the rotor core 232. The warped portion formed on the tip side of the salient pole piece 80b of the first core plate 80 is received in the gap formed between the opposing surface of one of the load receiving blocks and the salient pole.

[0061] The rotor of this embodiment has the same basic configuration as the above-described embodiment, and therefore can obtain the same basic effects as the above-described embodiment. However, in the rotor of this embodiment, the second core plates 81A, 81B without salient pole pieces protruding radially outward are arranged on both axial sides of the stacked first core plates 80 of the rotor core 232, thereby making it possible to further reduce the weight of the rotor core 232. This makes it possible to further reduce the weight of the entire rotor and further improve the controllability of the motor.

[0062] In addition, in the rotor of this embodiment, second core plates 81A, 81B of approximately the same shape are arranged on both axial sides of the stacked first core plate 80 of the rotor core 232, so there is no need for directionality when assembling the rotor core 232 into the magnet cover (it can be assembled in the same way from either axial direction), which has the advantage of making it easier to manufacture the rotor.

[0063] The present invention is not limited to the above-described embodiment, and various design modifications are possible without departing from the spirit and scope of the present invention. In each of the above embodiments, the spacer portion is configured by a second core plate disposed at the end of the rotor core, but the spacer portion is not limited to this configuration as long as it is configured to form an axial gap between the end face of the salient pole and the opposing face of the load receiving block. For example, the spacer portion may be configured by a non-magnetic plate material interposed between the rotor core and the load receiving block. Furthermore, the spacer portion is not limited to a plate material, and may be a block-shaped one, and the number of spacer blocks interposed between the rotor core and the load receiving block may be two or more. For example, three spacer blocks may be evenly arranged in the circumferential direction between the rotor core and the inner peripheral edge of the load receiving block. Furthermore, the spacer portion may be formed integrally with the load-receiving block so as to protrude from the annular portion of the load-receiving block toward the rotor core. In this case, the spacer portion formed on the load-receiving block abuts against the end face of the core body of the rotor core, thereby forming an axial gap between the opposing surface of the load-receiving block and the salient pole of the rotor core. The spacer portion may be formed of a boss portion formed on the axial end of the core body portion of the rotor core so as to protrude axially outward. In this case, the boss portion abuts against the load-receiving block, thereby forming an axial gap between the opposing surface of the load-receiving block and the salient pole of the rotor core. [Explanation of symbols]

[0064] 1...motor unit, 2...motor, 3...reduction section, 4...controller, 5...motor case, 6...first motor case, 6a...opening, 7...second motor case, 7a...opening, 8...stator, 9...rotor, 10...bottom, 11...connector, 13...rotor core, 16...outer flange section, 17...outer flange section, 20...stator core, 21...core main body section, 22...teeth, 23...insulator, 24...coil, 31...rotating shaft, 32...rotor core, 32A...core main body section, 32B...salient pole, 33...permanent magnet, 40...gear case, 40a...opening, 40b...side wall, 40c...bottom wall, 41...worm reduction mechanism, 42...gear accommodating section, 43...opening, 44...worm shaft, 45...worm wheel, 46...bearing, 47...bearing, 48...output shaft, 48a...spring Line, 49...bearing boss, 49...bearing boss, 50...first core plate, 50b...salient pole piece, 52...rib, 53...boss portion, 54...through hole, 61...magnetic detection element, 62...controller board, 63...cover, 70...weight support block, 70A...annular portion, 70B...leg portion, 70Ba...facing surface, 70C...end wall, 71...magnet cover, 71a...peripheral wall, 71A...annular portion, 71b ...flange portion, 71c...flange portion, 73...relief groove, 73a...engagement portion, 74...locking claw, 80...first core plate, 80a...base portion, 80b...salient pole piece, 81...second core plate, 81A...second core plate, 81B...second core plate, 132...rotor core, 181...second core plate, 181a...annular portion, 181b...claw portion, 232...rotor core, C...shaft center, d...gap

Claims

1. a rotor core having a substantially cylindrical core body and a plurality of salient poles protruding in a radial direction from an outer periphery of the core body; a plurality of permanent magnets arranged between adjacent salient poles in the circumferential direction of the rotor core; a substantially cylindrical magnet cover that covers the rotor core and the outer sides of the permanent magnets and has a flange portion bent radially inward at an axially outer end thereof; a load-receiving block disposed between an axially outer end of the rotor core and the flange portion, the load-receiving block being capable of transmitting an axial load between the flange portion and the rotor core; The rotor core is configured by stacking a plurality of core plates made of a magnetic material in the axial direction, A rotor characterized in that a spacer portion is arranged on at least one axial end side of the rotor core, the spacer portion forming an axial gap between the axially outer end face of the salient pole and an opposing surface of the load-receiving block that faces the axially outer end face.

2. 2. The rotor according to claim 1, wherein the spacer portion is formed of an annular plate material having approximately the same outer diameter as the core body portion.

3. The spacer portion is made of a plate material having a circular ring portion having approximately the same outer diameter as the core body portion, and a plurality of claw portions protruding radially from the circular ring portion and overlapping with the root portions of the salient poles.

2. The rotor according to claim 1, wherein a protruding length of the claw portion is set shorter than a protruding length of the salient pole.

4. 4. The rotor according to claim 2, wherein the spacer portion is made of a magnetic material and constitutes the core plate.

5. 5. The rotor according to claim 4, wherein the spacer portion is made of a plate material having the same thickness as the other core plates.

6. 6. The rotor according to claim 1, wherein the core plates adjacent in the lamination direction are fitted together by projections and recesses at portions other than the salient poles.

7. A rotor according to any one of claims 1 to 6; a stator disposed on an outer periphery of the rotor and configured to generate a magnetic field.

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