Electric Motor

Abstract

The present invention can manufacture high-quality electric motors with high yield. The electric motor (10) includes a stator (16) housed in a motor case (11), and a rotor (17) including a shaft (18) and a rotor body (20), wherein the shaft (18) is rotatably pivotally supported on the motor case (11), and the rotor body (20) has an annular magnet (29) arranged on the inner side of the stator (16). A magnet cover (53) for inserting into the rotor body (20) includes: a cylindrical portion (54) covering the outer peripheral surface of the annular magnet (29); a folded portion (55) abutting against the end face (51) of the rotor body (20); and a fastening end portion (69) fastened to a flange portion (50) provided on the shaft (18) in a manner covering the end face (52), and a snap-fit ​​claw portion (57) for snapping into the rotor (17) is provided on the folded portion (55).

Description

Technical Field

[0001] The present invention relates to an electric motor having a magnet mounted on a magnet mounting portion of a shaft directly or via a rotor core, and a method for manufacturing the electric motor. Background Art

[0002] Among electric motors, there are inner rotor type electric motors, which include: a stator provided with an armature winding and housed in a motor case; a shaft rotatably pivoted to support the motor case; and a magnet, i.e., a permanent magnet, mounted on the shaft and arranged inside the stator. Inner rotor type electric motors include a form in which the magnet is directly mounted on the magnet mounting portion of the shaft, and a form in which the magnet is mounted on the magnet mounting portion of the shaft via a rotor core.

[0003] Patent Documents 1 and 2 describe electric motors that protect magnets by covering them with magnet covers. The electric motor described in Patent Document 1 has a rotor cover, i.e., a magnet cover, which has: a cylindrical portion that covers the outer circumference of the magnet; a first clamping portion that is bent from one end of the cylindrical portion; and a second clamping portion that is bent from the other end of the cylindrical portion. In a state where a rotor core unit including a rotor core and a magnet is accommodated in the magnet cover having the first clamping portion on the bottom side, the second clamping portion on the open end side is extruded. The two clamping portions are in close contact with the end faces of the magnets.

[0004] The electric motor described in Patent Document 2 has two magnet covers each having a cup-shaped cross section, one of which covers one axial side of the magnet and the other covers the other axial side of the magnet. The bent piece of each magnet cover is engaged with a thinned portion formed on the rotor core to prevent the magnet cover from rotating relative to the magnet.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2017-28837

[0008] Patent Document 2: Japanese Patent Application Publication No. 2008-295140 Summary of the invention

[0009] Problems to be solved by the invention

[0010] If the magnet cover rotates relative to the magnet when the electric motor is used, the magnet cover will rub against the magnet to generate noise or damage the magnet, which will not improve the motor quality. Therefore, the magnet cover needs to be installed in a way that it does not rotate relative to the magnet.

[0011] However, if the magnet cover is pressed into or forcefully pressed against the outer circumference of the magnet so that the magnet cover does not rotate relative to the magnet, the magnet may be damaged during assembly of the rotor. If the second clamping portion is extruded while the rotor core unit is contained in the magnet cover as in the magnet cover described in Patent Document 1, the two clamping portions may be pressed against the end surface of the magnet and damage the magnet. Furthermore, if two magnet covers are mounted on the magnet as described in Patent Document 2, the cylindrical portion of the magnet cover needs to be firmly fastened to the outer circumference of the magnet in order to prevent the magnet cover from falling off the magnet, which may damage the magnet.

[0012] In this way, if the magnet is damaged when the magnet cover is attached to the magnet, the electric motor cannot be commercialized, and the manufacturing yield of the electric motor is reduced.

[0013] An object of the present invention is to manufacture high-quality electric motors at a high yield rate.

[0014] Technical means of solving problems

[0015] The electric motor of the present invention includes: a stator, which is accommodated in a motor box; and a rotor, including a shaft pivotally supported on the motor box for free rotation, and a rotor body having a magnet arranged on the inner side of the stator, and the electric motor has a magnet cover, and the magnet cover includes: a cylindrical portion, covering the outer peripheral surface of the magnet; a folded portion, which is provided at one end of the cylindrical portion and abuts against one of the end surfaces of the rotor body; and a fastening end, which is fastened to a flange portion provided on the shaft in a manner covering the other end surface of the rotor body, and a snap-fitting claw portion that snaps into the rotor is provided on the folded portion.

[0016] The manufacturing method of an electric motor of the present invention manufactures an electric motor, wherein the electric motor includes: a stator, which is accommodated in a motor box; and a rotor, including an axis pivotally supported on the motor box for free rotation, and a rotor body having a magnet arranged on the inner side of the stator, and the manufacturing method of the electric motor includes: a processing step of pressing a magnet cover, wherein the magnet cover has a cylindrical portion, a folded portion integrally provided at one end of the cylindrical portion and protruding radially inward, and a locking claw portion integrally provided at the folded portion; an assembly step of assembling the rotor, wherein the rotor includes a rotor body having the magnet and the axis; and an insertion step of inserting the rotor into the magnet cover so that the locking claw portion is engaged with the rotor to prevent the magnet cover from rotating relative to the rotor.

[0017] Effects of the Invention

[0018] The magnet cover has a folded portion that abuts against one of the end faces of the rotor body, and a fastening end portion that is fastened to a flange portion provided on the shaft in a manner that covers the other end face, and a snap-fitting claw portion that snaps into the rotor is provided on the folded portion. Since the snap-fitting claw portion snaps into the rotor, even if the cylindrical portion of the magnet cover is slowly inserted into the outer peripheral surface of the magnet, the magnet cover will not deviate in the rotation direction relative to the magnet. Therefore, there is no need to press the magnet into the magnet cover, and there is no need to strongly fasten the cylindrical portion of the magnet cover to the outer peripheral surface of the magnet, which can suppress damage to the magnet and enable the manufacture of electric motors with high-quality rotors at a high yield.

[0019] The folded portion of one end of the magnet cover abuts against one end surface of the rotor body, and the fastened end of the other end of the magnet cover is fastened to the edge, so that no axial external force is applied to the magnet, thereby preventing damage to the magnet. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a perspective view showing an electric motor according to an embodiment.

[0021] Figure 2 for Figure 1 Longitudinal section of .

[0022] Figure 3 for Figure 2 Enlarged cross-sectional view of .

[0023] Figure 4 A block diagram showing a rotation control circuit of a motor.

[0024] Figure 5 for Figure 2 An enlarged cross-sectional view of the rotor is shown.

[0025] Figure 6 To express Figure 5 A bottom view of the lower end surface of the rotor is shown.

[0026] Figure 7 This is an exploded perspective view of the rotor.

[0027] Figure 8 To indicate from Figure 7 A cross-sectional view of the magnet cover taken along line 8A-8A.

[0028] Fig. 9 (A)~ Fig. 9 (E) is a process diagram showing the pressing process sequence for manufacturing the magnet cover.

[0029] Fig.10 (A)~ Fig.10 (C) is a process diagram showing the sequence of inserting the rotor into the magnet cover when manufacturing the electric motor.

[0030] Fig.11 (A) Fig.11 (B) is a process diagram showing the procedure of fastening the opening end of the magnet cover to the flange portion of the rotor body.

[0031] Fig.12 (A) Fig.12 (B) is a process diagram showing the procedure of fastening the opening end of the magnet cover to the flange portion of the rotor body.

[0032] Fig.13 for Fig.12 (A) is a cross-sectional view along line 13-13.

[0033] Fig.14 It is a perspective view showing an electric motor according to another embodiment.

[0034] Fig.15 for Fig.14 Longitudinal section of .

[0035] Fig.16 for Fig.14 Enlarged cross-sectional view of .

[0036] Fig.17 for Fig.15 An enlarged cross-sectional view of the rotor is shown.

[0037] Fig.18 To express Fig.17 A bottom view of the lower end surface of the rotor is shown.

[0038] Fig.19 This is an exploded perspective view of the rotor.

[0039] Fig. 20 (A)~ Fig. 20 (C) is a process diagram showing the sequence of inserting the rotor into the magnet cover when manufacturing the electric motor.

[0040] [Explanation of Symbols]

[0041] 11: Motor box

[0042] 13: Bracket

[0043] 16: Stator

[0044] 17: Rotor

[0045] 18: Axis

[0046] 18a: Magnet mounting part

[0047] 20: Rotor body

[0048] 26: Rotor core

[0049] 29: Ring magnet

[0050] 33: Long hole

[0051] 34: stator core

[0052] 37: Coil

[0053] 40: Sensor disc

[0054] 41: Sensor substrate

[0055] 50: Flange

[0056] 50a: Confrontation

[0057] 50b: Conical

[0058] 51: First end face

[0059] 52: Second end face

[0060] 53: Magnetic cover

[0061] 54: Cylinder

[0062] 55: Retraction

[0063] 56: Gap

[0064] 57, 57a: Engaging claw portion

[0065] 58: Base end

[0066] 59: Front end

[0067] 61: Press-in section

[0068] 62: Guidance

[0069] 63: Notch

[0070] 64: Positioning hole

[0071] 66: convex part

[0072] 67: Flange

[0073] 68: Expansion section

[0074] 69: Fastening end

[0075] 71: Insert fixture

[0076] 72: Positioning pin

[0077] 73: Workpiece support fixture

[0078] 76: Reinforcement roller

[0079] 77: Support shaft

[0080] 78: Extruded components

[0081] 81: Flat surface

[0082] 81a: Guide surface

[0083] 81b: snap-fit ​​surface

[0084] 82: Step difference

[0085] 83: Notch

[0086] 84: Protrusion DETAILED DESCRIPTION

[0087] Hereinafter, embodiments of the present invention will be described in detail based on the accompanying drawings. Figure 1 and Figure 2 As shown in FIG. 1 , the electric motor 10 includes a motor case 11. The motor case 11 is formed by performing a pressing process such as deep drawing on a metal plate. Figure 2 As shown, the bottom wall portion 11a and the cylindrical portion 11b are provided, and a flange portion 11c is integrally provided at the opening end portion 12 of the cylindrical portion 11b. A bracket 13 made of a resin material is attached to the flange portion 11c via a plurality of screw members 14.

[0088] The bracket 13 is provided with a plurality of collars 15, and the electric motor 10 is mounted on a member (not shown) by means of screw members penetrating the collars 15. The electric motor 10 can be used for driving a brake device of an automobile, and in this case, the motor case 11 is mounted on a reducer by means of screw members penetrating the collars 15.

[0089] like Figure 2 As shown, the motor case 11 contains a stator 16, and the stator 16 is fixed to the cylindrical portion 11b of the motor case 11. The electric motor 10 has a rotor 17, and the rotor 17 includes a shaft 18 rotatably supported on the motor case 11, and a rotor body 20 arranged inside the stator 16 with a gap 19. The shaft 18 includes a magnet mounting portion 18a and a shaft portion 18b and a shaft portion 18c integrally formed at both ends thereof, and the outer diameter of the magnet mounting portion 18a is larger than that of the shaft portion 18b and the shaft portion 18c. The shaft portion 18c on the base end side of the shaft 18 is rotatably supported on the motor case 11 through a bearing 21, and the shaft portion 18b on the front end side is rotatably supported on the bracket 13 through a bearing 22. The bearing 21 is mounted on a cylinder 23 provided on the bottom wall 11 a of the motor case 11 , and the bearing 22 is mounted on a holder 24 mounted on the bracket 13 .

[0090] If the axis 18 Figure 2The lower end portion is the base end portion of the shaft 18, and the upper end portion is the front end portion, and a pinion gear 25 is installed at the front end portion. When the electric motor 10 is used for driving a brake device, the rotation of the pinion gear 25 is transmitted to the feed screw shaft via a reduction gear mechanism not shown in the figure. The feed screw shaft is screwed into a reciprocating member, and this reciprocating member is freely installed in the caliper of the brake device in the axial direction. The claws of the reciprocating member and the caliper facing it are respectively provided with pads that are squeezed by the brake disc of the electric brake device of the car, and the braking force is applied to the car by the electric motor 10.

[0091] like Figure 3 As shown, the rotor body 20 has a cylindrical rotor core 26, and the shaft 18 is inserted through an insertion hole 27 of the rotor core 26. An annular magnet 29 is fixed to the outer periphery of the rotor core 26 by an adhesive 28. Figure 1 to Figure 3 In the electric motor 10 shown, an annular magnet 29 is mounted on the magnet mounting portion 18a of the shaft 18 via the rotor core 26. The rotor core 26 is mounted between the magnet mounting portion 18a and the annular magnet 29. Thus, the rotor body 20 includes the annular magnet 29, the rotor core 26, and the magnet mounting portion 18a of the shaft 18.

[0092] The insertion hole 27 is provided with a plurality of grooves 31 extending in the axial direction. The rotor core 26 is formed by stacking a plurality of metal plates (electromagnetic steel plates) that are punched into a substantially annular shape by pressing. Each metal plate is provided with a through hole 32 for positioning when stacking, and a long hole 33 for achieving a lightweight rotor core 26. Figure 3 As shown in FIG. 1 , six long holes 33 are provided at equal intervals in the circumferential direction of the rotor core 26. For the long diameter of the long hole 33, the circumferential direction of the rotor core 26 is the long diameter. Figure 2 As shown, it extends in the axial direction of the rotor core 26 .

[0093] The ring magnet 29 is formed by alternately magnetizing a cylindrical member made of a magnetic material so that the magnetic poles are staggered in the circumferential direction and the N poles and the S poles are alternately magnetized. Figure 3 The annular magnet 29 shown is magnetized with ten magnetic poles in the circumferential direction, and the rotor body 20 has ten poles. Figure 3In the figure, the boundary portion of the magnetic pole of the annular magnet 29 is indicated by a dotted line. In this way, if the magnet of the rotor body 20 of the electric motor 10 is set to an annular magnet type, the magnetic poles can be evenly distributed in the circumferential direction, unlike the magnet of the surface magnet type or the embedded magnet type, and the rotor 17 can be manufactured with a small amount of assembly work. The magnet of the rotor body 20 can be set to the surface magnet type described above, or it can be set to the embedded magnet type. Regarding the surface magnet type magnet, it is thought that the arc-shaped magnet attached to the outer circumferential surface of the cylindrical member will fall off, and by setting it to an annular magnet type, the durability of the electric motor 10 can be improved.

[0094] The stator 16 has a stator core 34 that is substantially cylindrical in shape. Figure 3 As shown, the stator core 34 is formed by combining nine teeth 35 in the circumferential direction. Each tooth 35 is formed by stacking a plurality of metal plates (electromagnetic steel plates) punched by pressing. Each metal plate is provided with a through hole (not shown) for positioning during stacking. An insulator 36 made of insulating resin material is installed on each tooth 35, and a coil 37 is wound around the outside of the insulator 36. The coil 37 is wound around the six teeth 35. Figure 3 The stator 16 shown has nine coils 37 .

[0095] Each coil 37 sequentially forms three phases of U phase, V phase, and W phase in the circumferential direction, and each phase is formed by three coils 37. Figure 2 As shown, a busbar unit 38 is arranged on the end surface of the front end side of the stator 16. The terminals of each coil 37 are electrically connected to the external power supply through the busbar unit 38. The electric motor 10 is a brushless motor, and a sensor disc 40 is installed on the shaft 18 to detect the position of the rotation direction of the rotor 17. A magnet not shown in the figure is provided on the sensor disc 40. A sensor substrate 41 is installed on the bracket 13 facing the sensor disc 40, and a Hall element 42 is provided on the sensor substrate 41. This Hall element 42 senses the magnetic force of the magnet provided on the sensor disc 40.

[0096] Figure 4 The rotation control circuit has three Hall elements 42a to 42c corresponding to the three-phase coils. Each Hall element is installed on Figure 2 The sensor substrate 41 is shown. Figure 2Although one Hall element 42 is shown in the sensor substrate 41, three Hall elements 42a to 42c are provided on the sensor substrate 41 in a circumferentially staggered manner. Each Hall element 42a to 42c is a magnetic field detection element that detects the magnetic flux of a magnet provided on the sensor disk 40, thereby outputting a detection signal when the polarity of the magnetic pole portion of the rotor 17 becomes a neutral point from the N pole to the S pole. The position of the rotor 17 is detected based on the detection signal from the Hall element, and the energization switching action of each coil 37 is performed. As a sensor for detecting the rotational position, it is not limited to the Hall element, and a Hall integrated circuit (IC) can also be used. This Hall IC is formed by making an electronic element having a comparator function and a Hall element into a single chip.

[0097] The motor rotation control circuit has an inverter circuit 43, which is used to control the drive current of each coil 37 of the U phase, V phase and W phase. The inverter circuit 43 is a three-phase full-bridge inverter circuit, which has two switching elements T1 and T2, two switching elements T3 and T4, and two switching elements T5 and T6 connected in series, respectively, and are connected to the positive and negative output terminals of the DC power supply 44. One of the connection terminals of the coil 37 of the U phase is connected between the two switching elements T1 and T2. One of the connection terminals of the coil 37 of the V phase is connected between the two switching elements T3 and T4. One of the connection terminals of the coil 37 of the W phase is connected between the two switching elements T5 and T6. The other connection terminals of the coils 37 of the U phase, V phase and W phase are connected to each other, and each coil 37 is connected in a star connection. In addition, the connection method can also be a delta connection. By adjusting the timing of the control signal supplied to each switching element, the commutation action of each coil 37 is controlled.

[0098] The motor rotation control circuit has a controller 45, and a control signal is sent from the controller 45 to the inverter circuit 43 via a control signal output circuit 46. The detection signals of the Hall elements 42a to 42c as rotation position detection sensors are sent to the rotating body position detection circuit 47. The signal is sent from the rotating body position detection circuit 47 to the controller 45. The controller 45 has a microprocessor that calculates the control signal, and a memory that stores control programs and data.

[0099] The inverter circuit 43, the controller 45, the rotating body position detection circuit 47, etc. are arranged outside the motor, and the lead wire connecting one of the connection terminals of the coil of each phase to the inverter circuit 43 is as shown in FIG. Figure 1As shown, the lead wires connecting the three Hall elements 42a to 42c and the rotating body position detection circuit 47 pass through a cable guide 48 provided on the bracket 13 and are guided to the outside.

[0100] Figure 5 for Figure 2 and Figure 3 An enlarged cross-sectional view of the rotor 17 is shown. Figure 6 To express Figure 5 Bottom view of the lower end of the rotor, Figure 7 This is an exploded perspective view of the rotor. Figure 8 To indicate from Figure 7 A cross-sectional view of the magnet cover taken along line 8A-8A.

[0101] Figure 5 In the embodiment, the rotor body 20 has end faces at the top and bottom, one of which is set as the first end face 51, and the other end face is set as the second end face 52. The shaft 18 is provided with a flange 50, and the inner surface of the flange 50 has a portion that abuts against the end face of the rotor core 26 and a portion that abuts against the end face of the annular magnet 29, and the flange 50 abuts against the second end face 52 of the rotor body 20. The annular magnet 29 is covered by a magnet cover 53. The magnet cover 53 is made of stainless steel materials SUS304 and SUS305, which are non-magnetic materials, and does not affect the magnetic circuit of the annular magnet 29, thereby preventing the reduction of motor performance.

[0102] The magnet cover 53 includes a cylindrical portion 54 covering the outer peripheral surface of the annular magnet 29, and a folded portion 55 provided in an annular shape at one end of the cylindrical portion 54. The folded portion 55 is bent radially inward from the end of the cylindrical portion 54 toward the radial center of the cylindrical portion, and abuts against the first end surface 51 of the rotor body 20. The folded portion 55 does not abut against the end surface of the annular magnet 29, and a gap 56 is provided between the folded portion 55 and the end surface of the annular magnet 29.

[0103] The folded portion 55 is provided with three engaging claws 57 at equal intervals in the circumferential direction. The engaging claws 57 are bent in a right angle direction relative to the folded portion 55, extend from the folded portion 55 along the axial direction of the rotor body 20, and are substantially parallel to the cylindrical portion 54. The engaging claws 57 correspond to the position of the long hole 33. When the magnet cover 53 is inserted outside the annular magnet 29, the engaging claws 57 enter the inside of the long hole 33 and engage with the inner surface of the long hole 33 in the circumferential direction. The inner diameter of the cylindrical portion 54 of the magnet cover 53 is slightly larger than the outer diameter of the annular magnet 29. Therefore, the magnet cover 53 does not apply an external force to the annular magnet 29 to press the cylindrical portion 54 in, but rather inserts the cylindrical portion 54 outside the annular magnet 29 by slowly sliding. Thus, although the cylindrical portion 54 of the magnet cover 53 is not pressed into the annular magnet 29 , the engaging claws 57 engage with the long holes 33 as the engaging holes, thereby preventing the magnet cover 53 from deviating in the rotational direction relative to the annular magnet 29 .

[0104] like Figure 8 As shown, the engaging claw portion 57 has a base end portion 58 and a front end portion 59 on the side of the folded portion 55. A press-in portion 61 is provided on the base end side of the engaging claw portion 57. The width dimension L0 of the press-in portion 61 is set to be the same as or slightly larger than the long diameter of the long hole 33. When the annular magnet 29 is inserted into the magnet cover 53, the press-in portion 61 is pressed into the inner peripheral surface of the long hole 33 in close contact. The front end portion 59 is formed into a tapered shape whose width dimension gradually decreases toward the front end surface. Therefore, when the annular magnet 29 is inserted into the magnet cover 53, the front end portion 59 enters the long hole 33, and the side surface of the front end portion 59 becomes the guide portion 62. The engaging claw portion 57 is guided by the inner peripheral surface of the long hole 33 and inserted into the long hole 33. In order to make it easy for the engaging claw portion 57 to enter the long hole 33, the axial length L1 of the guide portion 62 is set to be longer than the length L2 of the press-in portion 61. The length L1 of the guide portion 62 is preferably set to be at least twice the length L2 of the press-fit portion 61 .

[0105] Six long holes 33 are formed, and three engaging claws 57 are provided. The engaging claws 57 engage with three of the six long holes 33. However, if more than three, for example, six engaging claws 57 are provided, the engaging claws 57 engage with all the long holes 33. The number of the long holes 33 as engaging holes is not limited to six, as long as three or more are provided. The engaging holes for the engaging claws 57 to engage are not limited to long holes, but may be perfectly circular holes.

[0106] like Figure 8As shown in the figure, notch portions 63 for bending are provided at the left and right side portions of the base end portion of the engaging claw portion 57. In this way, if the notch portion 63 is provided at the base end portion of the engaging claw portion 57, that is, at the boundary portion between the engaging claw portion 57 and the folded portion 55, the engaging claw portion 57 can be bent with high accuracy and easily when the engaging claw portion 57 is bent in a direction substantially at a right angle to the folded portion 55. It is also possible to improve the bending workability by using only the notch portion 63 on one side instead of providing the notch portion 63 on both sides of the engaging claw portion 57.

[0107] A positioning hole 64 is provided at the widthwise center of the base end of the engaging claw portion 57. The positioning hole 64 is used to attach the magnet cover 53 to the positioning pin of the jig when the rotor body 20 is inserted into the magnet cover 53. The positioning hole 64 is provided between the two notches 63 on the left and right sides, and in addition to the notches 63, it also has the function of facilitating the bending processability of the engaging claw portion 57.

[0108] Fig. 9 (A)~ Fig. 9 (E) is a process diagram showing a pressing process sequence for manufacturing the magnet cover 53 .

[0109] Fig. 9 (A) shows a magnet cover material 53a which is processed into a cup-shaped cross section by deep drawing the non-magnetic material blank. The magnet cover material 53a has a cylindrical portion 54 and a bottom wall portion 65. At one end of the cylindrical portion 54, a convex portion 66 is formed which protrudes axially outward from the bottom wall portion 65. If the flange portion 67 produced during the deep drawing of the magnet cover material 53a is cut, Fig. 9 As shown in (B), the magnet cover material 53b including the cylindrical portion 54 and the bottom wall portion 65 is processed and is in the process of being processed. Fig. 9 (C) is a longitudinal cross-sectional view showing a state where the bottom wall portion 65 has been punched by pressing. Fig. 9 (D) is Fig. 9 The 9D-9D line cross-sectional view of (C). In the bottom wall portion 65 of the magnet cover material 53c, as shown Fig. 9 As shown in (D), an annular folded portion 55 and three engaging claws 57 protruding radially inward from the folded portion 55 are formed. Furthermore, notches 63 are formed on both sides of the base end of the engaging claw 57, and a positioning hole 64 is formed in the width direction center of the engaging claw 57.

[0110] In the magnet cover material 53c, Fig. 9 As shown in (D), the two notches 63 and the positioning holes 64 are arranged in a straight line as shown by the double-dotted line. If this part is used as the bending center and the three engaging claws 57 are bent in a substantially right angle direction relative to the folded portion 55, as shown in Fig. 9 As shown in (E), the magnet cover 53 is manufactured in which the engaging claw portion 57 is bent relative to the folded portion 55. As described above, the notch portion 63 is provided at the base end portion of the bent portion of the engaging claw portion 57, so the bending process of the engaging claw portion 57 can be performed easily and with high accuracy.

[0111] In this way, through Fig. 9 (A)~ Fig. 9 The magnet cover 53 is manufactured by the pressing process shown in (E). The magnet cover 53 during manufacturing has a cylindrical portion 54, a folded portion 55 and an engaging claw portion 57 provided at one end of the cylindrical portion 54, and the cylindrical portion 54 extends straight to the other end. In addition, a convex portion 66 protruding axially outward is formed on the outer peripheral portion of the folded portion 55.

[0112] Fig.10 (A)~ Fig.10 (C) is an insertion process diagram showing the sequence of inserting the rotor 17 into the magnet cover 53 when manufacturing the electric motor 10. The rotor 17 is inserted into the magnet cover 53 in the rotor assembly process (not shown). Figure 7 Assemble as shown.

[0113] like Fig.10 As shown in (A), the magnet cover 53 is positioned and fixed on the insertion fixture 71. The insertion fixture 71 has a support hole for supporting the magnet cover 53, and three positioning pins 72 are provided at the bottom of the insertion fixture 71. Each positioning pin 72 is engaged with Fig. 9 The magnet cover 53 is thereby positioned and fixed to the insertion fixture 71. Fig.10 (A)~ Fig.10 (C) shows only a portion of the insertion jig 71.

[0114] Next, the rotor 17 is inserted into the magnet cover 53. At this time, the outer diameter of the rotor body 20 is slightly smaller than the inner diameter of the magnet cover 53, so the rotor can be easily inserted. Fig.10 (B) shows a state where the front end portion 59 of the engaging claw portion 57 enters the long hole 33 as the engaging hole. The front end portion 59 is tapered, and the width of the front end portion 59 is smaller than the long diameter of the long hole 33, so that the engaging claw portion 57 can be easily inserted into the long hole 33 without high-precision positioning of the rotor 17 relative to the magnet cover 53 in the rotation direction.

[0115] Fig.10(C) shows a state where the rotor 17 is inserted into the magnet cover 53 until the end surface of the folded portion 55 abuts against the first end surface 51, which is the lower end surface of the rotor body 20. At this time, the press-fit portion 61 provided on the base end side of the engaging claw portion 57 is pressed in close contact with the inner peripheral surface of the long hole 33. Thus, the magnet cover 53 is fixed to the rotor 17 by the press-fit portion 61, and the magnet cover 53 is prevented from rotating relative to the rotor 17. The annular magnet 29 is fixed to the rotor core 26 by the adhesive 28 during the assembly process of the rotor 17, and one end surface of the annular magnet 29 deviates from the end surface of the rotor core 26 and the magnet mounting portion 18a, and the other end surface abuts against the flange portion 50 for assembly. Therefore, when the rotor body 20 is inserted into the magnet cover 53, a gap 56 is formed between the annular magnet 29 and the folded portion 55, and the folded portion 55 does not abut against the end surface of the annular magnet 29.

[0116] Fig.11 (A) Fig.11 (B)~ Fig.13 It is a reinforcement process diagram showing a process of fastening the opening end of the magnet cover 53 to the flange portion 50 of the rotor body portion 20 .

[0117] like Fig.11 As shown in (A), the rotor 17 inserted into the magnet cover 53 is mounted on the workpiece support fixture 73. In addition, at the opening of the magnet cover 53, as shown in FIG. Fig.11 (A) Fig.11 As shown in (B), a diameter expansion portion 68 is provided whose diameter gradually increases toward the opening end surface. If the diameter expansion portion 68 is provided in this way, the rotor body 20 can be easily inserted into the magnet cover 53. Fig. 9 The expanded diameter portion 68 may be processed into the shape shown in (E) or as Fig. 9 As shown in (A), the enlarged diameter portion 68 is processed in the deep drawing process. In addition, the enlarged diameter portion 68 may not be provided.

[0118] The workpiece support fixture 73 has a support hole 74 that contacts the outer peripheral surface of the cylindrical portion 54 of the magnet cover 53, and a radial abutment surface 75 that faces the folded portion 55 is formed at the end portion on the bottom side of the support hole 74. When the rotor 17 is inserted into the support hole 74, the center axis of the rotor 17 becomes concentric with the fixture center axis Oj of the workpiece support fixture 73. An elastic force imparting portion 75a is provided on the radially outer portion of the abutment surface 75, and the convex portion 66 of the rotor 17 contacts the elastic force imparting portion 75a. Fig.11 As shown in (A), the abutment surface 75 includes an elastic force imparting portion 75a for contact with the front end of the projection 66 when the rotor 17 is mounted on the workpiece support fixture 73, and a close contact portion 75b which is radially inward of the elastic force imparting portion 75a.

[0119] like Fig.11As shown in (A), when an external force in the axial direction is applied to the rotor 17 in a state where the rotor 17 is supported by the workpiece supporting jig 73, the rotor 17 is supported by a force to such an extent that the rotor 17 can move in the axial direction.

[0120] A reinforcing roller 76 is disposed adjacent to the workpiece support fixture 73, and the reinforcing roller 76 is rotatably mounted on a support shaft 77 about the rotation center axis Or. The support shaft 77 is mounted by an arm (not shown) so as to be movable around the fixture center axis Oj of the rotor 17, that is, to be movable in a radial direction outside the rotor 17, and the support shaft 77 is movable in the radial direction relative to the fixture center axis Oj. Fig.11 (A) shows a state where the reinforcing roller 76 is brought close to the rotor 17 as indicated by arrow R and the reinforcing roller 76 contacts the enlarged diameter portion 68 of the magnet cover 53 .

[0121] like Fig.11 As shown in (B), when the rotor 17 is supported by the workpiece support fixture 73, as shown by the arrow S, the extrusion member 78 applies an axial extrusion force to the rotor 17 toward the contact surface 75 of the workpiece support fixture 73. If an extrusion force is applied to the rotor 17 in the direction toward the contact surface 75, as shown in Fig.11 As shown in (B), the convex portion 66 is contracted and deformed in the axial direction of the rotor 17 by the elastic force imparting portion 75a. Furthermore, the folded portion 55 is in close contact between the first end surface 51 of the rotor body 20 and the close contact portion 75b of the workpiece support fixture 73. As a result, a pressing force is applied to the cylindrical portion 54 in the axial direction E, and an axial elastic force is applied to the convex portion 66. The convex portion 66 is deformed in the axial direction, and an elastic force, that is, a spring force, is accumulated inside like a spring member.

[0122] Next, if Fig.12 As shown by the arrow R in (A), the support shaft 77 is moved toward the center axis Oj of the fixture, and as Fig.13 As shown, the support shaft 77 is made to perform a circumferential motion, i.e., a revolving motion, around the center axis Oj of the fixture as shown by the arrow T. As a result, the reinforcing roller 76 performs a rotational motion as shown by the arrow Q, while reinforcing the opening end of the magnet cover 53 to be closely attached to the outer peripheral surface of the flange portion 50, and a fastening end 69 is formed at the opening end of the magnet cover 53. When the magnet cover 53 is reinforced to be closely attached to the outer peripheral surface of the flange portion 50, as shown by the arrow Fig.12 As shown by arrow F in (A), an elastic force is applied to the cylindrical portion 54 in a direction of pulling toward the fastening end portion 69 formed at the open end. Therefore, if the rotor 17 is removed from the workpiece support fixture 73 after the fastening end portion 69 is processed, Fig.12 As shown by arrow G in (B), the cylindrical portion 54 generates a reaction force that presses the fastening end portion 69 toward the flange portion 50, and due to the reaction force, the folded portion 55 generates a force that presses in a direction toward the end surface 51 of the rotor body portion 20, that is, an elastic force.

[0123] In this way, the magnet cover 53 is pressed against the end face 51 of the rotor body 20 without the folded portion 55 at one end thereof contacting one end face of the annular magnet 29. On the other hand, the flange portion 50 contacts the other end face of the annular magnet 29, and the fastening end portion 69 of the magnet cover 53 is pressed against the flange portion 50, so that no axial load is applied to the annular magnet 29. Thus, the annular magnet 29 is prevented from being damaged. Furthermore, if Fig.12 As shown in (B), the outer peripheral surface of the flange portion 50 has an axial straight surface 50a and a tapered surface 50b whose diameter gradually decreases toward the outer end surface of the flange portion 50. If the outer diameter of the straight surface 50a is set to be slightly smaller than the outer diameter of the annular magnet 29, even if the fastening end 69 is formed on the magnet cover 53, no external force will be applied to the annular magnet 29 from the magnet cover 53.

[0124] like Fig.11 (A) Fig.11 (B) and Fig.12 (A) Fig.12 As shown in (B), the support shaft 77 is made to revolve around the center axis Oj of the fixture, but the workpiece support fixture 73 can also be made to revolve around the rotation center axis Or of the reinforcement roller 76, as long as the revolution motion of the rotation center axis Or and the revolving motion of the fixture center axis Oj are relative motions.

[0125] Thus, as described above, the method for manufacturing the electric motor 10 includes a step of manufacturing the rotor 17, and the electric motor 10 is manufactured through a step of assembling the rotor 17 to the stator 16 mounted on the motor case 11. Figure 7 and Figure 8 , the magnet cover 53 is shown in a state where the fastening end portion 69 is provided.

[0126] Fig.14 2 is a perspective view showing an electric motor 10a according to another embodiment. Fig.15 for Fig.14 A longitudinal cross-section of Fig.16 for Fig.14 In these figures, the same symbols are given to the components that are common to the components constituting the electric motor 10.

[0127] The electric motor 10a can be used for driving the brake device of the automobile, similarly to the electric motor 10. At this time, the motor box 11 is installed in a speed reducer gear mechanism (not shown) through a screw member penetrating the collar 15, and similarly to the electric motor 10, the electric motor 10a applies braking force to the automobile.

[0128] The diameter of the motor case 11 of the electric motor 10a is smaller than that of the motor case 11 of the electric motor 10. Fig.16As shown, an annular magnet 29 is directly fixed to the magnet mounting portion 18a of the shaft 18 by an adhesive 28, and the rotor body 20 is formed by the magnet mounting portion 18a and the annular magnet 29. The annular magnet 29 has ten poles, similarly to the electric motor 10. The stator core 34 also has nine teeth 35 around which coils 37 are wound, and each coil 37 constitutes three phases of U phase, V phase, and W phase.

[0129] like Fig.15 As shown in the figure, a sensor disk 40 provided with a magnet is mounted on the shaft 18, and a sensor substrate 41 is mounted on the bracket 13 facing the sensor disk 40. Hall elements 42a to 42c that sense magnets are provided on the sensor substrate 41. Figure 4 The rotation control circuit shown in the figure also has a rotation control circuit of an inverter circuit 43 to control the commutation operation of each coil 37. Fig.14 and Fig.15 As shown, a cable guide 48a is provided on the bracket 13. The cable guide 48a is provided with power wiring connected to the coil 37, sensor wiring connected to the Hall elements 42a to 42c, and power supply and ground wiring for supplying power to elements provided on the sensor substrate 41. Fig.15 In FIG. 1 , a terminal 39 a of a power wiring, a terminal 39 b of a sensor wiring, and a terminal of a wiring for a power source are shown.

[0130] Fig.17 for Fig.15 An enlarged cross-sectional view of the rotor is shown. Fig.18 To express Fig.17 The bottom view of the lower end surface of the rotor shown, Fig.19 This is an exploded perspective view of the rotor.

[0131] Two annular magnets 29 are glued to the magnet mounting portion 18a, and the rotor body 20 is formed by the two annular magnets 29 and the magnet mounting portion 18a. A flange portion 50 is integrally provided on the shaft 18, and the end surface of the annular magnet 29 abuts against the flange portion 50. The first end surface 51 of the rotor body 20 is formed by the end surface of the magnet mounting portion 18a, and the second end surface 52 is formed by the end surface of the annular magnet 29. In addition, one annular magnet 29 having the length of two annular magnets 29 may be fixed to the magnet mounting portion 18a, and the flange portion 50 and the shaft 18 may be provided as separate components, similar to the flange portion 50 of the electric motor 10 described above.

[0132] like Fig.17 As shown, the magnet cover 53 includes: a cylindrical portion 54 covering the outer peripheral surface of the annular magnet 29; a folded portion 55 covering the first end surface 51 of the rotor body 20; and a fastening end portion 69 fastened to the flange portion 50. Fig.18As shown in FIG. 1 , two engaging claws 57a are provided facing each other at positions offset by 180 degrees in the circumferential direction on the folded portion 55. Each engaging claw 57a extends radially inward from the folded portion 55 and engages with the outer circumferential surface of the shaft 18 constituting the rotor 17. The engaging claws 57a engage with the outer circumferential surface of the shaft 18, thereby preventing the magnet cover 53 from rotating in the circumferential direction relative to the annular magnet 29.

[0133] Two flat surfaces 81 are formed on the outer peripheral surface of the shaft 18 corresponding to the engaging claws 57a. The two flat surfaces 81 are parallel to each other and are also called two cut surfaces. Fig.17 and Fig.19 As shown in the figure, there is a guide surface 81a having a width dimension H on the end surface side of the shaft 18, and an engagement surface 81b on the rotor body 20 side having a larger width dimension than the guide surface 81a, and a step portion 82 is provided between the guide surface 81a and the engagement surface 81b. The guide surface 81a and the engagement surface 81b are connected in the axial direction via the step portion 82.

[0134] On the other hand, the front end surface of the engaging claw portion 57a ​​is as shown in FIG. Fig.18 As shown, notches 83 are provided on both sides of the engaging claw 57a extending in the width direction of the flat surface 81. The notches 83 allow the front end of the engaging claw 57a to elastically deform in the axial direction. Three protrusions 84 are provided at the front end of the engaging claw 57a.

[0135] The interval between the protrusion 84 of one engaging claw portion 57a ​​and the protrusion 84 of the other engaging claw portion 57a ​​is set to be larger than the width dimension H of the guide surface 81a, that is, the thickness dimension, and is set to be smaller than the width dimension of the engaging surface 81b. As a result, when the magnet cover 53 is inserted outside the annular magnet 29, the protrusion 84 of the engaging claw portion 57a ​​gently contacts the guide surface 81a, and the insertion action of the magnet cover 53 is guided. If the protrusion 84 of the engaging claw portion 57a ​​exceeds the step difference portion 82 through the insertion action and is inserted to the position of the engaging surface 81b, the protrusion 84 is engaged with the engaging surface 81b. The protrusion 84 is slightly elastically deformed in the axial direction due to the engaging force. In this way, the protrusion 84 at the front end of the engaging claw portion 57a ​​is engaged with the engaging surface 81b and is squeezed, thereby reliably preventing the magnet cover 53 from deviating from the annular magnet 29 in the rotation direction.

[0136] Fig. 20 (A)~ Fig. 20 (C) is a process diagram showing the sequence of inserting the rotor 17 into the magnet cover 53 when manufacturing the electric motor 10a. The rotor 17 is inserted into the magnet cover 53 in the rotor assembly process (not shown). Fig.19 Assemble as shown.

[0137] like Fig. 20As shown in (A), the magnet cover 53 is arranged on the insertion fixture 71. Next, as Fig. 20 As shown in (B), the rotor 17 is inserted from the open end of the magnet cover 53. At this time, the outer diameter of the rotor body 20 is slightly smaller than the inner diameter of the magnet cover 53, so the rotor body 20 can be easily inserted. Fig. 20 (B) shows a state where the rotor 17 is inserted into the magnet cover 53 until the protrusion 84 at the front end of the engaging claw portion 57a ​​reaches the position of the guide surface 81a of the flat surface 81. At this time, there is a gap between the protrusion 84 and the flat surface 81, and the rotor 17 can be easily inserted into the magnet cover 53 by using the flat surface 81 as the position of the engaging claw portion 57a.

[0138] Fig. 20 (C) shows a state where the rotor 17 is inserted into the magnet cover 53 until the end surface 51 of the rotor body 20 abuts against the folded portion 55. At this time, the protrusion 84 provided at the front end of the engaging claw portion 57a ​​is in close contact with the engaging surface 81b of the flat surface 81 and is pressed in. Thus, the magnet cover 53 is fixed to the rotor 17 via the engaging surface 81b, and the magnet cover 53 is prevented from rotating relative to the rotor 17.

[0139] The annular magnet 29 is fixed to the magnet mounting portion 18a by the adhesive 28 during the assembly process of the rotor 17, and one end face of the annular magnet 29 is offset from the end face 51 of the magnet mounting portion 18a, and the other end face is abutted against the flange portion 50. Therefore, when the rotor body 20 is inserted into the magnet cover 53, a gap 56 is formed between the annular magnet 29 and the folded portion 55, and the folded portion 55 does not abut against the end face of the annular magnet 29.

[0140] Thus, the rotor 17 inserted into the magnet cover 53 is made Figure 1 to Figure 3 The rotor 17 shown in the figure is similarly transported to the same place as the one used for reinforcement processing. Fig.11 (A) Fig.11 The workpiece support fixture 73 shown in (B) is the same as the workpiece support fixture 73. Fig.11 (A) Fig.11 (B) and Fig.12 (A) Fig.12 The same process as the reinforcing process shown in (B) is performed, and the open end of the magnet cover 53 is fastened to the flange portion 50 of the rotor body, and a fastening end portion 69 is processed at the end of the magnet cover 53.

[0141] The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the invention.

Claims

1. An electric motor, comprising: a stator housed in a motor box; and a rotor including a shaft rotatably pivotally supported on the motor box and a rotor body having a magnet disposed inside the stator, and The electric motor has a magnet cover, the magnet cover comprising: A cylindrical portion covering the outer circumference of the magnet; a folded portion provided at one end of the cylindrical portion and abutting against one end surface of the rotor body portion; and a fastening end portion fastened to a flange portion provided on the shaft in a manner covering the other end surface of the rotor body portion, The folded portion is provided with an engaging claw portion engaged with the rotor. The inner diameter of the cylindrical portion is larger than the outer diameter of the magnet, the electric motor comprises a rotor core, the rotor core is provided with an engagement hole extending in the axial direction, and is installed between the magnet mounting portion of the shaft and the magnet, the engagement claw portion extends in the axial direction from the folded portion and is engaged with the inner surface of the engagement hole in the circumferential direction, A press-in portion pressed into the inner circumferential surface of the engaging hole is provided at the base end of the engaging claw portion, and a guide portion is provided at the front end of the engaging claw portion. The guide portion has a smaller width in the circumferential direction than the press-in portion and guides the engaging claw portion when the engaging claw portion is inserted into the engaging hole.

2. The electric motor according to claim 1, wherein: The engagement holes and the engagement claws are provided at three or more locations at equal intervals in the circumferential direction.

3. The electric motor according to claim 1, wherein: The axial length of the guide portion is at least twice the length of the press-fit portion.

4. The electric motor according to claim 1 or 2, wherein: A notch portion for bending is provided on a side of a base end portion of the engaging claw portion.

5. The electric motor according to claim 1 or 2, wherein: A positioning hole is provided at a center portion in the width direction of the engaging claw portion.

6. The electric motor according to claim 1 or 2, wherein: A gap is provided between the folded portion and the magnet.

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