JP7149783B2 - ELECTRIC MOTOR AND ELECTRIC MOTOR MANUFACTURING METHOD - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric motor having a magnet attached directly or via a rotor core to a magnet attachment portion of a shaft, and a method of manufacturing the electric motor.

An electric motor includes a stator provided with an armature winding and housed in a motor case, a shaft rotatably supported by the motor case, and a magnet mounted on the shaft and arranged inside the stator. There is an inner rotor type consisting of permanent magnets. Inner rotor type electric motors include a form in which a magnet is directly attached to a magnet attachment portion of a shaft and a form in which a magnet is attached to a magnet attachment portion of a shaft via a rotor core.

Patent Documents 1 and 2 describe an electric motor in which a magnet is covered with a magnet cover to protect the magnet. The electric motor described in Patent Document 1 includes a cylindrical portion that covers the outer periphery of a magnet, a first holding portion that is bent from one end of the cylindrical portion, and a second holding portion that is bent from the other end of the cylindrical portion. It has a rotor cover or magnet cover with a portion. A rotor core unit consisting of a rotor core and a magnet is accommodated in a magnet cover having a first holding portion on the bottom side, and a second holding portion on the opening end side is pressed. Both clamps are tightly attached to the end face of the magnet.

The electric motor described in Patent Document 2 has two magnet covers each having a cup-shaped cross section, one magnet cover covering one side of the magnet in the axial direction, and the other magnet cover covering the other side of the magnet in the axial direction. cover the The bent pieces of the respective magnet covers are fitted into recessed portions formed on the rotor core to prevent the magnet covers from rotating with respect to the magnets.

JP 2017-28837 A JP 2008-295140 A

As described in Patent Document 1, the rotor core unit is arranged in the outer mold, and the open end of the magnet cover is sandwiched between the outer collet and the inner collet in order to press the second clamping portion on the open end side. is pulled radially inward. Since the second clamping portion is bent in a direction perpendicular to the cylindrical portion with the outer peripheral edge portion of the magnet as a base end, a bending force is applied to the magnet from the second clamping portion. Therefore, a large external force is applied from the magnet cover to the outer peripheral edge portion of the magnet, which may damage the magnet.

As described above, without using the outer collet and the inner collet, it is possible to press the open end of the magnet cover with a crimping punch to bend the holding portion in the radial direction. However, if the magnet is inserted into the cylindrical portion of the magnet cover so that the magnet cover does not come into close contact with the outer peripheral surface of the magnet, bending the opening end of the magnet cover with a caulking punch will cause the cylindrical portion of the magnet cover to move radially. It will swell outward.

On the other hand, when the magnet is press-fitted into the cylindrical portion of the magnet cover and the magnet cover is brought into close contact with the outer peripheral surface of the magnet, even if the opening end of the magnet cover is bent with a crimping punch, the cylindrical portion of the magnet cover does not move in the radial direction. Although it does not bulge outward, the press-fitting load and the stress generated during press-fitting are high, and there is a risk of damaging the magnet.

In this way, if the magnet is damaged when the magnet cover is attached to the magnet, such an electric motor cannot be commercialized, resulting in a decrease in the manufacturing yield of the electric motor.

SUMMARY OF THE INVENTION It is an object of the present invention to manufacture a high-quality electric motor with a high yield.

An electric motor according to the present invention includes a rotor including a stator housed in a motor case, a rotor body having a shaft rotatably supported by the motor case, and a magnet disposed inside the stator, An electric motor comprising: a magnet cover having a cylindrical portion that covers the outer peripheral surface of the magnet; a folded portion that is provided at one end of the cylindrical portion and contacts one end surface of the rotor main body; A flange provided on the shaft so as to cover the other end surface of the main body , and a gap provided between one end surface of the magnet and the folded portion, which is provided on the outer peripheral portion of the folded portion so as to protrude axially outward. and a fastening end provided at the other end of the magnet cover and crimped to the outer peripheral surface of the flange in the radial direction .

A method of manufacturing an electric motor according to the present invention includes a stator housed in a motor case, a rotor main body having a shaft rotatably supported by the motor case, and a magnet arranged inside the stator. A method of manufacturing an electric motor comprising: a cylindrical portion; a folded portion integrally provided at one end of the cylindrical portion and protruding radially inward ; a working step of press-working a magnet cover having a convex portion protruding in a direction ; an assembling step of assembling a rotor having a rotor main body portion having the magnet and the shaft; the other end of the magnet cover radially on the outer peripheral surface of the flange provided on the shaft so as to cover the other end surface of the rotor main body. a crimping step of crimping to form a fastening end portion at the other end portion, and contracting and deforming the convex portion so that the convex portion applies an axial elastic force to the cylindrical portion .

An elastic force in the axial direction, that is, a spring force is generated in the cylindrical portion of the magnet cover, and this elastic force presses the folded back of one end of the magnet cover against the one end of the rotor main body, and the other end of the magnet cover. The fastening end is pressed against the collar, and the magnet cover is securely fixed to the magnet. The magnet cover has a fastening end portion that is radially crimped to the outer peripheral surface of the flange provided on the shaft to generate an axial elastic force in the cylindrical portion, and the fastening end portion contacts the magnet. no. As a result, an electric motor having a high-quality rotor can be manufactured with high yield without damaging the magnet by the fastening end of the magnet cover.

A folded portion of one end of the magnet cover abuts on one end surface of the rotor main body, and a fastening end of the other end of the magnet cover is fastened to the edge, so that no external force is applied to the magnet in the axial direction. . As a result, damage to the magnet can be suppressed.

It is a perspective view showing an electric motor which is one embodiment. FIG. 2 is a longitudinal sectional view of FIG. 1; 3 is an enlarged cross-sectional view of FIG. 2; FIG. 3 is a block diagram showing a motor rotation control circuit; FIG. 3 is an enlarged cross-sectional view of the rotor shown in FIG. 2; FIG. FIG. 6 is a bottom view showing the lower end surface of the rotor shown in FIG. 5; 3 is an exploded perspective view of the rotor; FIG. 8A is a cross-sectional view showing the magnet cover as seen from the direction of line 8A-8A in FIG. 7; FIG. (A) to (E) are process diagrams showing a press working procedure for manufacturing the magnet cover. (A) to (C) are process diagrams showing a procedure for inserting a rotor into a magnet cover when manufacturing an electric motor. (A) and (B) are process diagrams showing a procedure for fastening the opening end of the magnet cover to the flange of the rotor main body. (A) and (B) are process diagrams showing a procedure for fastening the opening end of the magnet cover to the flange of the rotor main body. 13 is a cross-sectional view taken along line 13-13 in FIG. 12(A); FIG. FIG. 11 is a perspective view showing an electric motor according to another embodiment; FIG. 15 is a longitudinal sectional view of FIG. 14; 15 is an enlarged cross-sectional view of FIG. 14; FIG. 16 is an enlarged cross-sectional view of the rotor shown in FIG. 15; FIG. FIG. 18 is a bottom view showing the lower end surface of the rotor shown in FIG. 17; 3 is an exploded perspective view of the rotor; FIG. (A) to (C) are process diagrams showing a procedure for inserting a rotor into a magnet cover when manufacturing an electric motor.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. As shown in FIGS. 1 and 2, the electric motor 10 has a motor case 11 . The motor case 11 is formed by subjecting a metal plate to press work such as deep drawing, and as shown in FIG. 2, has a bottom wall portion 11a and a cylindrical portion 11b. is integrally provided with a flange portion 11c. A bracket 13 made of a resin material is attached to the flange portion 11 c by a plurality of screw members 14 .

A plurality of collars 15 are attached to the bracket 13, and the electric motor 10 is attached to a member (not shown) by a screw member penetrating each collar 15. As shown in FIG. This electric motor 10 can be applied to drive a brake device of an automobile, in which case the motor case 11 is attached to the speed reducer by a screw member penetrating the collar 15 .

As shown in FIG. 2 , the motor case 11 accommodates a stator 16 , and the stator 16 is fixed to the cylindrical portion 11 b of the motor case 11 . The electric motor 10 has a rotor 17. The rotor 17 includes a shaft 18 rotatably supported by the motor case 11, and a rotor main body 20 arranged inside the stator 16 with a gap 19 interposed therebetween. there is The shaft 18 has a magnet mounting portion 18a and shaft portions 18b and 18c integrated at both ends thereof, and the outer diameter of the magnet mounting portion 18a is larger than that of the shaft portions 18b and 18c. A shaft portion 18c on the base end side of the shaft 18 is rotatably supported by the motor case 11 through a bearing 21, and a shaft portion 18b on the tip end side is rotatably supported on the bracket 13 by a bearing 22. As shown in FIG. The bearing 21 is attached to a cylindrical portion 23 provided on the bottom wall portion 11 a of the motor case 11 , and the bearing 22 is attached to a holder 24 attached to the bracket 13 .

Assuming that the lower end of the shaft 18 in FIG. 2 is the base end of the shaft 18 and the upper end thereof is the tip, a pinion gear 25 is attached to the tip. When the electric motor 10 is applied to drive a brake device, the rotation of the pinion gear 25 is transmitted to the feed screw shaft via a reduction gear mechanism (not shown). The feed screw shaft is screwed to a reciprocating member that is axially reciprocally mounted on the caliper of the brake device. The reciprocating member and the pawl portion of the caliper opposed thereto are provided with pads that are pressed against the brake disc of the electric brake device of the automobile, and the electric motor 10 applies braking force to the automobile.

As shown in FIG. 3 , the rotor main body 20 has a cylindrical rotor core 26 , and a shaft 18 is inserted through an insertion hole 27 of the rotor core 26 . A ring magnet 29 is fixed to the outer circumference of the rotor core 26 with an adhesive 28 . In the electric motor 10 shown in FIGS. 1 to 3, a ring magnet 29 is attached to the magnet attachment portion 18a of the shaft 18 with the rotor core 26 interposed therebetween. The rotor core 26 is mounted between the magnet mounting portion 18 a and the ring magnet 29 . Thus, the rotor main body 20 includes the ring magnet 29, the rotor core 26, and the magnet mounting portion 18a of the shaft 18. As shown in FIG.

A plurality of grooves 31 are provided in the insertion hole 27 so as to extend in the axial direction. The rotor core 26 is formed by laminating a plurality of metal plates (electromagnetic steel plates) stamped into a substantially annular shape by press working. Each metal plate has a through hole 32 for positioning during lamination and an elongated hole 33 for reducing the weight of the rotor core 26 . As shown in FIG. 3, six elongated holes 33 are provided at regular intervals in the circumferential direction of the rotor core 26 . The long hole 33 has a major diameter in the circumferential direction of the rotor core 26 and extends in the axial direction of the rotor core 26 as shown in FIG.

The ring magnet 29 is formed by alternately magnetizing a cylindrical member made of a magnetic material so that N poles and S poles as magnetic poles are shifted in the circumferential direction. The ring magnet 29 shown in FIG. 3 is magnetized with 10 magnetic poles in the circumferential direction, and the rotor body 20 has 10 poles. In FIG. 3, the boundaries of the magnetic poles of the ring magnet 29 are indicated by dashed lines. Thus, when the magnet of the rotor main body 20 of the electric motor 10 is of a ring magnet type, the magnetic poles can be evenly allocated in the circumferential direction, unlike the magnets of the surface magnet type or the embedded magnet type. The rotor 17 can be manufactured with a small number of assembly man-hours. The magnet of the rotor main body 20 may be of the above-described surface magnet type, or may be of the embedded magnet type. With the surface magnet type magnet, the arc-shaped magnet attached to the outer peripheral surface of the cylindrical member may come off, but the ring magnet type can improve the durability of the electric motor 10. can.

The stator 16 has a substantially cylindrical stator core 34 . The stator core 34 is formed by combining nine teeth 35 in the circumferential direction, as shown in FIG. Each tooth portion 35 is formed by laminating a plurality of metal plates (electromagnetic steel plates) punched by press working. Each metal plate is provided with a through hole (not shown) for positioning during lamination. An insulator 36 made of an insulating resin material is attached to each tooth portion 35 , and a coil 37 is wound around the outside of the insulator 36 . Coils 37 are wound around nine teeth 35 , and the stator 16 shown in FIG. 3 has nine coils 37 .

Each coil 37 constitutes three phases, a U phase, a V phase, and a W phase, in order in the circumferential direction, and each phase is formed by three coils 37 . As shown in FIG. 2, a busbar unit 38 is arranged on the end face of the stator 16 on the tip side. A terminal of each coil 37 and an external power supply are electrically connected by the bus bar unit 38 . The electric motor 10 is a brushless motor, and a sensor disk 40 is attached to the shaft 18 to detect the rotational position of the rotor 17 . The sensor disk 40 is provided with a magnet (not shown). A sensor substrate 41 is attached to the bracket 13 so as to face the sensor disk 40 , and the sensor substrate 41 is provided with a Hall element 42 that senses the magnetic force of the magnet provided on the sensor disk 40 .

FIG. 4 is a block diagram showing a motor rotation control circuit. The rotation control circuit has three Hall elements 42a to 42c corresponding to the three-phase coils, and each Hall element is attached to the sensor substrate 41 shown in FIG. 2 as described above. Although one Hall element 42 is shown on the sensor substrate 41 in FIG. 2, three Hall elements 42a to 42c are provided on the sensor substrate 41 so as to be displaced in the circumferential direction. Each of the Hall elements 42a to 42c detects the magnetic flux of the magnet provided on the sensor disk 40, and outputs a detection signal when the polarity of the magnetic pole portion of the rotor 17 changes from the N pole to the S pole neutral point. It is a magnetic field detection element that outputs, detects the position of the rotor 17 based on the detection signal from the Hall element, and performs the energization switching operation for each coil 37 . The sensor for detecting the rotational position is not limited to the Hall element, and a Hall IC in which an electronic element having a comparator function and a Hall element are integrated into one chip may be used.

The motor rotation control circuit has an inverter circuit 43 for controlling drive currents for the U-phase, V-phase and W-phase coils 37 . The inverter circuit 43 is a three-phase full-bridge inverter circuit, and has two switching elements T1 and T2, two switching elements T3 and T4, and two switching elements T5 and T6 connected in series. They are connected to the positive and negative output terminals of the DC power supply 44, respectively. One connection terminal of the U-phase coil 37 is connected between the two switching elements T1 and T2. One connection terminal of the V-phase coil 37 is connected between the two switching elements T3 and T4. One connection terminal of the W-phase coil 37 is connected between the two switching elements T5 and T6. The other connection terminals of the U-phase, V-phase, and W-phase coils 37 are connected to each other, and the coils 37 are star-connected. Note that a delta connection may be used as the connection method. The commutation operation for each coil 37 is controlled by adjusting the timing of the control signal supplied to each switching element.

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 the control signal output circuit 46 . Detection signals from Hall elements 42 a to 42 c as rotational position detection sensors are sent to rotor position detection circuit 47 . A signal is sent from the rotor position detection circuit 47 to the controller 45 . The controller 45 has a microprocessor for calculating control signals and a memory for storing control programs and data.

The inverter circuit 43, controller 45, rotor position detection circuit 47, etc. are provided outside the motor. , the cable is guided to the outside through a cable guide 48 provided on the bracket 13. Lead wires connecting the three Hall elements 42 a to 42 c and the rotor position detection circuit 47 are guided outside through a cable guide 49 provided on the bracket 13 .

FIG. 5 is an enlarged cross-sectional view of rotor 17 shown in FIGS. 6 is a bottom view showing the lower end portion of the rotor in FIG. 5, FIG. 7 is an exploded perspective view of the rotor, and FIG. 8 is a cross-sectional view showing the magnet cover seen from the direction of line 8A-8A in FIG. .

The rotor main body 20 has upper and lower end faces in FIG. A collar portion 50 is provided on the shaft 18. The inner surface of the collar portion 50 has a portion that contacts the end surface of the rotor core 26 and a portion that contacts the end surface of the ring magnet 29. The collar portion 50 is formed on the rotor body. It abuts the second end face 52 of the portion 20 . The ring magnet 29 is covered with a magnet cover 53 . The magnet cover 53 is made of stainless steel SUS304 and SUS305, which are non-magnetic materials, and prevents deterioration of motor performance without affecting the magnetic path of the ring magnet 29 .

The magnet cover 53 has a cylindrical portion 54 covering the outer peripheral surface of the ring magnet 29 and a folded portion 55 annularly provided at one end of the cylindrical portion 54 . The folded portion 55 is bent radially inward from the end portion of the cylindrical portion 54 toward the radial center portion of the cylindrical portion and contacts the first end surface 51 of the rotor body portion 20 . A gap 56 is provided between the folded portion 55 and the end surface of the ring magnet 29 without contacting the end surface of the ring magnet 29 .

The folded portion 55 is provided with three engaging claw portions 57 at equal intervals in the circumferential direction. The engaging claw portion 57 is bent in a direction perpendicular to the folded portion 55 , extends from the folded portion 55 in the axial direction of the rotor main body 20 , and is substantially parallel to the cylindrical portion 54 . The engaging claw portion 57 corresponds to the position of the elongated hole 33 , and when the magnet cover 53 is inserted to the outside of the ring magnet 29 , the engaging claw portion 57 enters the elongated hole 33 and moves around the circumference of the elongated hole 33 . engages the inner surface of the direction; The inner diameter of the cylindrical portion 54 of the magnet cover 53 is slightly larger than the outer diameter of the ring magnet 29 . Therefore, the magnet cover 53 is inserted to the outside of the ring magnet 29 by gently sliding the cylindrical portion 54 without applying an external force to the ring magnet 29 and press-fitting it. As described above, the cylindrical portion 54 of the magnet cover 53 is not press-fitted into the ring magnet 29, but the engaging claw portions 57 are engaged with the elongated holes 33 serving as the engaging holes, so that the magnet cover 53 is removed from the ring magnet 29. is prevented from being displaced in the direction of rotation with respect to the

As shown in FIG. 8, the engaging claw portion 57 has a base end portion 58 on the side of the folded portion 55 and a tip end portion 59 . A press-fitting portion 61 is provided on the base end side of the engaging claw portion 57, and the width dimension L0 of the press-fitting portion 61 is set to be the same as or slightly larger than the major diameter of the long hole 33. is inserted into the ring magnet 29 , the press-fitting portion 61 is press-fitted in close contact with the inner peripheral surface of the elongated hole 33 . The distal end portion 59 is formed in a tapered shape in which the width dimension gradually decreases toward the distal end surface. As a result, when the magnet cover 53 is inserted into the ring magnet 29 , the distal end portion 59 enters the long hole 33 , the side surface of the distal end portion 59 serves as the guide portion 62 , and the engaging claw portion 57 guides the inner periphery of the long hole 33 . It is inserted into the long hole 33 while being guided by the surface. The axial length L1 of the guide portion 62 is set longer than the length L2 of the press-fitting portion 61 so that the engaging claw portion 57 can be easily inserted into the elongated hole 33. As shown in FIG. It is preferable that the length L1 of the guide portion 62 is at least twice the length L2 of the press-fitting portion 61. As shown in FIG.

Six long holes 33 are formed, and three engaging claw portions 57 are provided, and the engaging claw portions 57 are engaged with three of the six long holes 33 . However, if three or more, for example, six, engaging claw portions 57 are provided, the engaging claw portions 57 are engaged with all the elongated holes 33 . The number of long holes 33 as engaging holes is also not limited to six, and may be three or more. The engagement hole with which the engagement claw portion 57 is engaged is not limited to the long hole, and may be a perfect circular hole.

As shown in FIG. 8 , notch portions 63 for bending are provided on left and right side portions of the proximal end portion of the engaging claw portion 57 . In this way, when 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 is substantially perpendicular to the folded portion 55 . When bending in the direction, the bending of the engaging claw portion 57 can be easily performed with high accuracy. Bending workability can be improved even if the cutout portions 63 are not provided on both the left and right sides of the engaging claw portion 57, but only on one side.

A positioning hole 64 is provided in the widthwise central portion of the proximal end portion of the engaging claw portion 57 . The positioning holes 64 are used to attach the magnet cover 53 to the positioning pins of the jig when inserting the rotor body 20 into the magnet cover 53 . The positioning hole 64 is provided between the two cutouts 63 on the left and right sides, and has a function of facilitating bending workability of the engaging claw portion 57 in addition to the cutouts 63 .

9A to 9E are working process diagrams showing the press working procedure for manufacturing the magnet cover 53. FIG.

FIG. 9(A) shows a magnet cover material 53a in the process of being processed into a cup-shaped cross section by deep drawing the blank material of the non-magnetic material described above. The magnet cover material 53 a has a cylindrical portion 54 and a bottom wall portion 65 , and a convex portion 66 projecting axially outward from the bottom wall portion 65 is formed at one end of the cylindrical portion 54 . When the flange portion 67 generated during the deep drawing process of the magnet cover material 53a is cut, the magnet cover material 53b, which is in the process of being processed and consists of the cylindrical portion 54 and the bottom wall portion 65, is processed as shown in FIG. 9(B). be done. FIG. 9(C) is a vertical cross-sectional view showing the magnet cover material 53c in which the bottom wall portion 65 is punched out by a press, and FIG. 9(D) is a cross-sectional view taken along line 9D-9D in FIG. 9(C). be. As shown in FIG. 9D, the bottom wall portion 65 of the magnet cover material 53c has an annular folded portion 55 and three engaging claw portions 57 protruding radially inward from the folded portion 55. It is formed. Further, notch portions 63 are formed on both sides of the proximal end portion of the engaging claw portion 57, and a positioning hole 64 is formed in the central portion of the engaging claw portion 57 in the width direction.

In this magnet cover material 53c, as shown in FIG. 9(D), two cutouts 63 and a positioning hole 64 are arranged in a straight line as indicated by a chain double-dashed line. When the three engaging claw portions 57 are bent in a direction substantially perpendicular to the folded portion 55 as the bending center, the engaging claw portions 57 are bent with respect to the folded portion 55 as shown in FIG. 9(E). A magnet cover 53 is manufactured. As described above, since the notch portion 63 is provided at the bent portion, that is, the base end portion of the engaging claw portion 57, the bending process of the engaging claw portion 57 can be easily performed with high accuracy.

In this manner, the magnet cover 53 is manufactured by the pressing process shown in FIG. The magnet cover 53 at the time of manufacture has a cylindrical portion 54, a folded portion 55 provided at one end of the cylindrical portion 54, and an engaging claw portion 57. The cylindrical portion 54 extends straight toward the other end. ing. A convex portion 66 protruding axially outward is formed on the outer peripheral portion of the folded portion 55 .

10A to 10C are insertion process diagrams showing the procedure for inserting the rotor 17 into the magnet cover 53 when manufacturing the electric motor 10. FIG. The rotor 17 is assembled as shown in FIG. 7 in a rotor assembly process (not shown).

As shown in FIG. 10(A), the magnet cover 53 is positioned and fixed on the insertion jig 71 . The insertion jig 71 has a support hole for supporting the magnet cover 53 , and three positioning pins 72 are provided at the bottom of the insertion jig 71 . Each positioning pin 72 is fitted into the positioning hole 64 shown in FIG. 9(D). As a result, the magnet cover 53 is positioned and fixed to the insertion jig 71 . 10, only part of the insertion jig 71 is shown.

The rotor 17 is then inserted into the magnet cover 53 . At this time, the outer diameter of the rotor main body 20 is slightly smaller than the inner diameter of the magnet cover 53, so that it can be easily inserted. FIG. 10B shows a state in which the tip portion 59 of the engaging claw portion 57 has entered the long hole 33 as the engaging hole. The tip portion 59 has a tapered shape, and the width of the tip portion 59 is smaller than the major diameter of the elongated hole 33. Therefore, the rotor 17 can be easily engaged without positioning the rotor 17 with respect to the magnet cover 53 with high accuracy in the rotational direction. The claw portion 57 can be easily inserted into the elongated hole 33 .

FIG. 10C shows a state in which the rotor 17 is inserted into the magnet cover 53 until the end face of the folded portion 55 contacts the lower end face of the rotor main body 20, that is, the first end face 51. FIG. At this time, the press-fitting portion 61 provided on the proximal end side of the engaging claw portion 57 is press-fitted in close contact with the inner peripheral surface of the elongated hole 33 . As a result, 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 with respect to the rotor 17 . The ring magnet 29 is fixed to the rotor core 26 with an adhesive 28 in the process of assembling the rotor 17 . is assembled against the Therefore, when the rotor main body 20 is inserted into the magnet cover 53 , a gap 56 is formed between the ring magnet 29 and the folded portion 55 so that the folded portion 55 does not contact the end surface of the ring magnet 29 .

11 to 13 are crimping process diagrams showing the process of fastening the open end of the magnet cover 53 to the flange 50 of the rotor main body 20. FIG.

As shown in FIG. 11A, the rotor 17 inserted into the magnet cover 53 is attached to the work support jig 73. As shown in FIG. As shown in FIG. 11, the opening of the magnet cover 53 is provided with an enlarged diameter portion 68 whose diameter gradually increases toward the opening end face. By providing the enlarged diameter portion 68 in this manner, the rotor body portion 20 can be easily inserted into the magnet cover 53 . The enlarged diameter portion 68 may be processed after the magnet cover 53 is manufactured into the shape shown in FIG. 9(E), or may be processed in the deep drawing process as shown in FIG. 9(A). Also good. Alternatively, the enlarged diameter portion 68 may not be provided.

The work support jig 73 has a support hole 74 that contacts the outer peripheral surface of the cylindrical portion 54 of the magnet cover 53 . A face 75 is formed. When the rotor 17 is inserted into the support hole 74 , the center axis of the rotor 17 becomes concentric with the jig center axis Oj of the work support jig 73 . An elastic force applying 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 applying portion 75a. As shown in FIG. 11A, the abutment surface 75 includes an elastic force imparting portion 75a with which the tip of the convex portion 66 contacts when the rotor 17 is attached to the work support jig 73, and an elastic force imparting portion 75a. also has a radially inner tightening portion 75b.

As shown in FIG. 11A, when the rotor 17 is supported by the work supporting jig 73, the rotor 17 can move in the axial direction when an external force is applied to the rotor 17. supported by force.

A crimping roller 76 is arranged adjacent to the work support jig 73, and the crimping roller 76 is mounted on a support shaft 77 so as to be rotatable about the rotation center axis Or. The support shaft 77 is attached by an arm (not shown) so as to be rotatable around the jig center axis Oj of the rotor 17, that is, to be able to revolve radially outwardly of the rotor 17. The support shaft 77 is attached to the jig center axis Oj. is radially movable with respect to the FIG. 11A shows a state in which the crimping roller 76 is brought closer to the rotor 17 as indicated by an arrow R, and the crimping roller 76 is brought into contact with the enlarged diameter portion 68 of the magnet cover 53 .

As shown in FIG. 11B, while the rotor 17 is supported by the work support jig 73, the rotor 17 is moved from the work support jig 73 by the pressing member 78 as indicated by the arrow S. A pressing force is applied in the axial direction toward the abutment surface 75 . When a pressing force is applied to the rotor 17 in the direction toward the abutting surface 75, the projections 66 are contracted and deformed in the axial direction of the rotor 17 by the elastic force imparting portions 75a, as shown in FIG. 11B. Further, the folded portion 55 is tightened between the first end surface 51 of the rotor main body 20 and the tightening portion 75b of the work support jig 73. As shown in FIG. As a result, a pressing force is applied to the cylindrical portion 54 in the axial direction E, and an elastic force in the axial direction is applied to the convex portion 66 . The convex portion 66 is collapsed in the axial direction, and elastic force, that is, spring force is accumulated inside like a spring member.

Next, as indicated by arrow R in FIG. 12(A), the support shaft 77 is moved toward the jig central axis Oj, and as indicated by arrow T in FIG. Secondly, it is caused to revolve around the jig center axis Oj. As a result, the crimping roller 76 crimps the opening end of the magnet cover 53 to the outer peripheral surface of the collar portion 50 while rotating as indicated by an arrow Q, and the opening end of the magnet cover 53 has a fastening end. A portion 69 is formed. When the magnet cover 53 is crimped to the outer peripheral surface of the flange portion 50, it is pulled toward the fastening end portion 69 formed at the open end of the cylindrical portion 54, as indicated by arrow F in FIG. 12(A). A directional elastic force is applied. Therefore, when the rotor 17 is removed from the work support jig 73 after the fastening end portion 69 is machined, the fastening end portion 69 is attached to the cylindrical portion 54 as indicated by the arrow G in FIG. 12(B). A reaction force is generated to press the rotor 50 toward the end face 51 of the rotor main body 20 , that is, an elastic force.

Thus, the magnet cover 53 is pressed against the end surface 51 of the rotor main body 20 without the folded portion 55 at one end thereof contacting the one end surface of the ring magnet 29 . On the other hand, the flange 50 contacts the other end surface of the ring magnet 29 , and the fastening end 69 of the magnet cover 53 is pressed against the flange 50 , so no load is applied to the ring magnet 29 in the axial direction. This prevents the ring magnet 29 from being damaged. Moreover, as shown in FIG. 12B, the outer peripheral surface of the flange portion 50 has a straight surface 50a extending in the axial direction and a tapered surface 50b whose diameter gradually decreases toward the outer end surface of the flange portion 50. ing. If the outer diameter of the straight surface 50a is set slightly smaller than the outer diameter of the ring magnet 29, even if the fastening end portion 69 is formed on the magnet cover 53, the ring magnet 29 will not be subjected to an external force from the magnet cover 53. do not have.

As shown in FIGS. 11 and 12, the support shaft 77 is caused to revolve around the jig center axis Oj, and the work support jig 73 is caused to revolve around the rotation center axis Or of the crimping roller 76. The orbital motion of the rotation center axis Or and the jig center axis Oj may be relative.

As described above, the method for manufacturing the electric motor 10 includes the step of manufacturing the rotor 17 , and the electric motor 10 is assembled through the steps of assembling the rotor 17 to the stator 16 assembled to the motor case 11 . is manufactured. 7 and 8 show the magnet cover 53 with the fastening end 69 provided.

14 is a perspective view showing an electric motor 10a of another embodiment, FIG. 15 is a longitudinal sectional view of FIG. 14, and FIG. 16 is an enlarged horizontal sectional view of FIG. In these figures, the same reference numerals are given to the members having commonality with the members constituting the electric motor 10 described above.

Like the electric motor 10, the electric motor 10a can be applied to drive a brake device of an automobile. In that case, the motor case 11 is attached to a speed reducer gear mechanism (not shown) by means of a screw member penetrating the collar 15, and the electric motor 10a applies a braking force to the automobile in the same manner as the electric motor 10. FIG.

The diameter of the motor case 11 of the electric motor 10 a is smaller than that of the motor case 11 of the electric motor 10 . As shown in FIG. 16, a ring magnet 29 is directly fixed to the magnet mounting portion 18a of the shaft 18 with an adhesive 28, and the magnet mounting portion 18a and the ring magnet 29 form the rotor body portion 20. As shown in FIG. The ring magnet 29 has ten poles, like the electric motor 10 described above. The stator core 34 also has nine teeth portions 35 around which coils 37 are wound, and each coil 37 constitutes three phases of U-phase, V-phase and W-phase.

As shown in FIG. 15, a sensor disk 40 provided with a magnet is attached to the shaft 18 , and a sensor substrate 41 is attached to the bracket 13 so as to face the sensor disk 40 . Hall elements 42a to 42c sensitive to magnets are provided on the sensor substrate 41, and the commutation operation for each coil 37 is controlled by a rotation control circuit having an inverter circuit 43, similar to the rotation control circuit shown in FIG. be. One cable guide 48a is provided on the bracket 13, as shown in FIGS. The cable guide 48a includes power wiring connected to the coil 37, sensor wiring connected to the Hall elements 42a to 42c, power supply and ground wiring for supplying power to the elements provided on the sensor substrate 41, and the like. of wiring. FIG. 15 shows one power wiring terminal 39a, one sensor wiring terminal 39b, and a power supply wiring terminal.

17 is an enlarged cross-sectional view of the rotor shown in FIG. 15. FIG. 18 is a bottom view showing the lower end surface of the rotor shown in FIG. 17, and FIG. 19 is an exploded perspective view of the rotor.

Two ring magnets 29 are adhered to the magnet mounting portion 18a, and the rotor body portion 20 is formed by the two ring magnets 29 and the magnet mounting portion 18a. A collar portion 50 is provided integrally with the shaft 18 , and the end face of the ring magnet 29 abuts on the collar portion 50 . A first end surface 51 of the rotor main body 20 is formed by an end surface of the magnet mounting portion 18 a , and a second end surface 52 is formed by an end surface of the ring magnet 29 . One ring magnet 29 having a length of two ring magnets 29 may be fixed to the magnet mounting portion 18a. It may be a separate member.

As shown in FIG. 17 , the magnet cover 53 is fastened to the cylindrical portion 54 covering the outer peripheral surface of the ring magnet 29 , the folded portion 55 covering the first end face 51 of the rotor main body 20 , and the collar portion 50 . and a fastening end 69 . As shown in FIG. 18, the folded portion 55 is provided with two engaging claw portions 57a facing each other at positions 180 degrees apart in the circumferential direction. Each engaging claw portion 57 a extends radially inward from the folded portion 55 and engages with the outer peripheral surface of the shaft 18 that constitutes the rotor 17 . By engaging the engaging claw portion 57 a with the outer peripheral surface of the shaft 18 , the magnet cover 53 is prevented from rotating with respect to the ring magnet 29 in the circumferential direction.

Two flat surfaces 81 are formed on the outer peripheral surface of the shaft 18 so as to correspond to the engaging claw portions 57a. The two flat surfaces 81 are parallel to each other and are also called chamfered surfaces. As shown in FIGS. 17 and 19, the two flat surfaces 81 as chamfered surfaces are a guide surface 81a having a width dimension H on the end face side of the shaft 18 and a rotor having a width dimension larger than this. A stepped portion 82 is provided between the guide surface 81a and the engaging surface 81b. The guide surface 81a and the engaging surface 81b are connected in the axial direction with a stepped portion 82 interposed therebetween.

On the other hand, as shown in FIG. 18, the tip surface of the engaging claw portion 57a extends along the width direction of the flat surface 81, and cutout portions 83 are provided on both sides of the engaging claw portion 57a. there is By providing the notch portion 83, the distal end portion of the engaging claw portion 57a is elastically deformed in the axial direction. Three projections 84 are provided at the tip of the engaging claw portion 57a.

The distance between the protrusion 84 of one engaging claw portion 57a and the protrusion 84 of the other engaging claw portion 57a is set larger than the width dimension H of the guide surface 81a, that is, the thickness dimension, and the width of the engaging surface 81b It is set smaller than the size. As a result, when the magnet cover 53 is inserted to the outside of the ring magnet 29, the projection 84 of the engaging claw portion 57a is lightly brought into contact with the guide surface 81a to guide the insertion operation of the magnet cover 53. As shown in FIG. When the protrusion 84 of the engaging claw portion 57a is inserted to the position of the engaging surface 81b beyond the stepped portion 82 by the insertion operation, the protrusion 84 engages with the engaging surface 81b. The projection 84 is slightly elastically deformed in the axial direction by the engagement force. In this manner, the protrusion 84 at the tip of the engaging claw portion 57a is engaged with and pressed against the engaging surface 81b, so that the magnet cover 53 is reliably displaced from the ring magnet 29 in the rotational direction. is prevented.

20A to 20C are process diagrams showing the procedure for inserting the rotor 17 into the magnet cover 53 when manufacturing the electric motor 10a. The rotor 17 is assembled as shown in FIG. 19 in a rotor assembly process (not shown).

As shown in FIG. 20(A), the magnet cover 53 is arranged on the insertion jig 71 . Then, as shown in FIG. 20B, the rotor 17 is inserted through the open end of the magnet cover 53 . At this time, the outer diameter of the rotor main body 20 is slightly smaller than the inner diameter of the magnet cover 53, so that it can be easily inserted. FIG. 20(B) is
The rotor 17 is inserted into the magnet cover 53 until the protrusion 84 at the tip of the engaging claw portion 57a reaches the position of the guide surface 81a of the flat surface 81. FIG. 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 with the flat surface 81 positioned as the engaging claw portion 57a.

FIG. 20(C) shows a state in which the rotor 17 is inserted into the magnet cover 53 until the end surface 51 of the rotor main body 20 abuts the folded portion 55 . At this time, the projection 84 provided at the tip of the engaging claw portion 57a is pressed into the engaging surface 81b of the flat surface 81 in close contact therewith. As a result, the magnet cover 53 is fixed to the rotor 17 by the engagement surface 81 b and is prevented from rotating with respect to the rotor 17 .

The ring magnet 29 is fixed to the magnet mounting portion 18a with an adhesive 28 in the process of assembling the rotor 17. One end surface of the ring magnet 29 is displaced from the end surface 51 of the magnet mounting portion 18a, and the other end surface is the flange portion 50. is assembled against the Therefore, when the rotor main body 20 is inserted into the magnet cover 53 , a gap 56 is formed between the ring magnet 29 and the folded portion 55 so that the folded portion 55 does not contact the end surface of the ring magnet 29 .

The rotor 17 inserted into the magnet cover 53 in this manner is attached to the workpiece support jig 73 shown in FIG. It is transported to a work support jig similar to the 11 and 12, the opening end of the magnet cover 53 is fastened to the flange 50 of the rotor main body, and the fastening end is attached to the end of the magnet cover 53. 69 are processed.

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

11 Motor Case 13 Bracket 16 Stator 17 Rotor 18 Shaft 18a Magnet Mounting Part 20 Rotor Body 26 Rotor Core 29 Ring Magnet 33 Long Hole 34 Stator Core 37 Coil 40 Sensor Disk 41 Sensor Board 50 Flange 50a Straight Surface 50b Tapered Surface 51 First End surface 52 Second end surface 53 Magnet cover 54 Cylindrical portion 55 Folded portion 56 Gap 57, 57a Engagement claw portion 58 Base end portion 59 Tip portion 61 Press-fit portion 62 Guide portion 63 Notch portion 64 Positioning hole 66 Protruding portion 67 Flange portion 68 Expanded diameter portion 69 Fastened end portion 71 Insertion jig 72 Positioning pin 73 Work support jig 76 Crimping roller 77 Support shaft 78 Pressing member 81 Flat surface 81a Guide surface 81b Engagement surface 82 Stepped portion 83 Notch 84 Projection

Claims (9)

An electric motor comprising a stator housed in a motor case, a rotor having a shaft rotatably supported by the motor case, and a rotor main body having a magnet arranged inside the stator. ,
a magnet cover having a cylindrical portion that covers the outer peripheral surface of the magnet, and a folded portion that is provided at one end of the cylindrical portion and contacts one end surface of the rotor main body;
a flange provided on the shaft so as to cover the other end surface of the rotor main body;
a convex portion protruding axially outward from the outer peripheral portion of the folded portion and forming a gap between one end surface of the magnet and the folded portion;
a fastening end provided at the other end of the magnet cover and radially tightened to the outer peripheral surface of the flange . 2. The electric motor according to claim 1 , wherein said flange is a separate member from said shaft. 2. The electric motor according to claim 1 , wherein said flange is integral with said shaft. An electric motor according to any one of claims 1-3 , wherein the magnet is a ring magnet. 5. The electric motor according to any one of claims 1 to 4 , wherein the flange has an outer peripheral surface that continues to the outer peripheral surface of the magnet and a tapered surface that tapers outward in the axial direction from the outer peripheral surface. an electric motor. Electric motor according to any one of claims 1 to 5 , used for driving electric brakes of a motor vehicle. A method for manufacturing an electric motor comprising: a stator housed in a motor case; a rotor having a rotor body having a shaft rotatably supported by the motor case; and a magnet disposed inside the stator. and
A magnet cover having a cylindrical portion, a folded portion integrally provided at one end of the cylindrical portion and protruding radially inward, and a convex portion provided axially outwardly protruding from an outer peripheral portion of the folded portion. a processing step of pressing;
an assembling step of assembling a rotor including a rotor main body having the magnet and the shaft;
The magnet cover is attached to the outer peripheral surface of the flange provided on the shaft so as to cover the other end surface of the rotor main body while the folded portion is in contact with one end surface of the rotor main body. The other end is crimped in the radial direction to form a fastening end at the other end , and the convex portion is contracted and deformed so that the convex portion applies an elastic force in the axial direction to the cylindrical portion. process and
A method for manufacturing an electric motor, comprising: In the method for manufacturing an electric motor according to claim 7 ,
The rotor is mounted on a work support jig that has an abutment surface that abuts against the folded portion of the magnet cover of the rotor and an arcuate surface that contacts the outer peripheral surface of the cylindrical portion, and the other end portion of the magnet cover is mounted on the work support jig. While rotating the crimping roller that presses, the rotation center axis of the crimping roller is relatively revolved around the center axis of the rotor, thereby forming the fastening end in the crimping process. manufacturing method. In the method for manufacturing an electric motor according to claim 8,
A pressing member applies a pressing force in a direction toward the abutment surface to the rotor, and the projections provided on the outer peripheral portion of the folded portion and protruding axially outward are contracted and deformed by the abutment surface in the crimping step. A method for manufacturing an electric motor.

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