JP2022049106A - Brushless motor - Google Patents

Abstract

To provide a brushless motor capable of facilitating assembly to a shaft of a ring magnet.SOLUTION: A brushless motor comprises: a stator 15; a shaft 16 having a shaft part provided with a flange 51 and a rotor part 18 disposed inside the stator; and a ring magnet 31 that is fixed by an adhesive agent on an outer peripheral surface of a rotor core mounted to an outer peripheral surface 19 of the rotor part 18 or the outer side of the rotor part 18. A stopper part 56 to be abut against a radially inner side part of an end surface of the ring magnet 31 and a large diameter part 57 forming an adhesive agent reservoir groove 58 by facing an end surface 52 of the ring magnet 31 are provided at the flange 51. When the ring magnet 31 is moved toward the flange 51, an adhesive agent 26 leaking to the end surface 52 is received in the adhesive agent reservoir groove 58.SELECTED DRAWING: Figure 5

Description

The present invention relates to a brushless motor having a rotor with a ring magnet and a stator with a coil.

A brushless motor has a form having a stator mounted in a motor case and a rotor provided on a shaft rotatably supported by the motor case and provided with a ring magnet. Patent Document 1 discloses a brushless motor in which a ring magnet is attached to an outer peripheral surface of a magnet mounting portion provided on a rotor portion of a shaft. On the other hand, Patent Document 2 discloses a brushless motor in which a ring magnet is attached to an outer peripheral surface of a magnet mounting portion of a rotor core mounted on the outside of the rotor portion of the shaft.

As described above, the shaft of the brushless motor has a form in which a ring magnet is directly attached to the rotor portion of the shaft and a form in which the ring magnet is attached to the rotor portion of the shaft via a rotor core. In each form, the ring magnet is glued to the rotor portion of the shaft either directly or via a rotor core.

Japanese Unexamined Patent Publication No. 2020-10490 Japanese Unexamined Patent Publication No. 2019-140888

The shaft is provided with a flange to set the axial position of the ring magnet with respect to the shaft. To bond the ring magnet directly to the rotor of the shaft, apply an adhesive to the outer peripheral surface of the rotor, assemble the ring magnet axially from the tip of the shaft, and ring magnet until the end is abutted against the flange. Is shifted in the axial direction of the shaft.

When moving the ring magnet axially, the adhesive is partially scraped off the end face of the ring magnet, and when the end face of the ring magnet is abutted against the flange, the ring magnet and the flange are radially outward. Part of the adhesive will squeeze out. Therefore, after fitting the ring magnet to the rotor portion of the shaft, it is necessary to wipe off the adhesive that has squeezed out of the ring magnet. As described above, if it is necessary to wipe off the adhesive, there is a problem that the man-hours for assembling work increase and the workability for assembling the ring magnet to the shaft is poor.

The problem of poor workability is the same in a brushless motor in which a rotor core is attached to the rotor portion of the shaft and a ring magnet is attached to the shaft via the rotor core.

An object of the present invention is to provide a brushless motor capable of improving the workability of assembling a ring magnet to a shuff.

The brushless motor of the present invention includes a stator, a shaft portion provided with a flange, and a rotor portion integrally provided with the shaft portion and arranged inside the stator, and a shaft rotatably supported by the shaft, and the above. A stopper portion having a ring magnet fixed by an adhesive to the outer peripheral surface of the rotor portion or the outer peripheral surface of the rotor core mounted on the outer side of the rotor portion, and abutted against the radial inner portion of the end surface of the ring magnet. And a large-diameter portion that faces the end face of the ring magnet and forms an adhesive reservoir groove are provided on the flange, and when the ring magnet is moved toward the flange, the adhesive that protrudes from the end face is adhered. The agent is housed in the adhesive reservoir.

The brushless motor of the present invention includes a stator, a shaft portion provided with a flange, and a rotor portion integrally provided with the shaft portion and arranged inside the stator, and a shaft rotatably supported by the shaft, and the above. The ring magnet has a ring magnet fixed by an adhesive to the outer peripheral surface of the rotor portion or the outer peripheral surface of the rotor core mounted on the outer side of the rotor portion, and the ring magnet is provided with an end surface facing the flange. The magnet member 1 and the second magnet member provided with the facing surface facing the facing surface of the first magnet member are provided, and the first magnet member and the second magnet member face each other. An adhesive reservoir groove is formed on the outer peripheral surface corresponding to the surface, and when the second magnet member is moved toward the first magnet member, the adhesive protruding from the facing surface is adhered. It is housed in the agent reservoir.

The brushless motor of the present invention includes a stator, a shaft portion provided with a flange, and a rotor portion integrally provided with the shaft portion and arranged inside the stator, and a shaft rotatably supported by the shaft, and the above. A ring magnet fixed by an adhesive to the outer peripheral surface of the rotor portion or the outer peripheral surface of the stator core arranged outside the rotor portion, and the ring magnet is a first magnet member provided with an end surface facing the flange. And a second magnet member provided with a facing surface facing the facing surface of the first magnet member, the facing surface of the first magnet member and the facing surface of the second magnet member. It has a spacer ring which is positioned between the two magnet members and mounted on the outer peripheral surface to form an adhesive storage groove between the two facing surfaces, and the second magnet member is the first magnet member. The adhesive that has squeezed out from the facing surface when moved toward the magnet is accommodated in the adhesive reservoir.

With the adhesive applied to the outer peripheral surface of the rotor portion of the shaft or the outer peripheral surface of the rotor core mounted on the outside of the rotor portion, a ring magnet is fitted to the outer peripheral surface and moved in the axial direction of the shaft. As a result, when the ring magnet is attached to the shaft, even if the adhesive applied to the outer peripheral surface squeezes out of the ring magnet, the squeezed out adhesive is stored in the adhesive reservoir, so the adhesive is applied to the outside of the ring magnet. Is prevented from sticking out. This eliminates the need for wiping off the adhesive that has squeezed out, and can improve the workability of assembling the ring magnet to the shaft.

When the adhesive reservoir groove is formed between the flange of the shaft and the end face of the ring magnet, a step corresponding to the adhesive reservoir groove is formed between the ring magnet and the flange. By forming the step in this way, the magnetic flux density between the ring magnet and the stator core can be increased, and the induced voltage of the brushless motor can be increased.

It is a perspective view which shows the appearance of the brushless motor which is one Embodiment. It is a vertical sectional view of FIG. It is an enlarged cross-sectional view of FIG. It is a block diagram which shows the rotation control circuit of a motor. FIG. 2 is an enlarged cross-sectional view showing a rotor assembly including a shaft and a ring magnet shown in FIG. 2. (A) is an enlarged cross-sectional view of part A shown in FIG. 5, and (B) is a cross-sectional view of a portion similar to (A) in a brushless motor as a comparative example. (A) to (C) are process diagrams showing a process of assembling the ring magnet to the rotor portion of the shaft. It is sectional drawing which shows the rotor assembly which is another embodiment. It is sectional drawing which shows the rotor assembly which is still another embodiment. It is a process diagram which shows the process of assembling the ring magnet to the outer peripheral surface of the shaft shown in FIG. It is sectional drawing which shows the rotor assembly which is still another embodiment. It is a process diagram which shows the process of assembling the ring magnet to the outer peripheral surface of the shaft shown in FIG. 11. It is sectional drawing of the brushless motor which is another embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each drawing, the members having a commonality are designated by the same reference numerals.

The brushless motor 10 shown in FIGS. 1 and 2 includes a motor case 11. The motor case 11 is formed by pressing a metal plate by deep drawing or the like, and as shown in FIG. 2, has a bottomed cylindrical portion 11b provided with a bottom wall portion 11a, and the cylindrical portion 11b. A flange portion 11c is provided at the open end portion 12 of the above. A resin bracket 13 is attached to the flange portion 11c, and the bracket 13 is attached to the axial end portion of the motor case 11.

A plurality of collars 14a to 14c are attached to the bracket 13, and the brushless motor 10 is attached to a member (not shown) by a screw member penetrating each of the collars 14a to 14c. The brushless 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 collars 14a to 14c.

As shown in FIGS. 2 and 3, a cylindrical stator 15 is fixed to the cylindrical portion 11b of the motor case 11, and the shaft 16 of the motor having the center of the stator 15 as the rotation center axis rotates on the motor case 11. It is freely attached. The shaft 16 has shaft portions 17a and 17b at both ends and a rotor portion 18 integrated therein, and the rotor portion 18 is arranged inside the stator 15.

The shaft portion 17a on the proximal end side of the shaft 16 is rotatably supported by the motor case 11 by the bearing 21, and the shaft portion 17b on the distal end side is rotatably supported by the bracket 13 by the bearing 22. The bearing 21 is held by a tubular portion 23 provided on the bottom wall portion 11a of the motor case 11. On the other hand, the bearing 22 is held by the metal bearing holder 24 fixed to the bracket 13.

When the lower shaft portion 17a in FIG. 2 of the shaft 16 is the base end portion of the shaft 16 and the upper shaft portion 17b is the tip portion, the pinion gear 25 is attached to the output end which is the tip portion. When the brushless 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 lead screw shaft is screw-coupled to a reciprocating member mounted axially reciprocatingly on the caliper of the brake device. A pad pressed against the brake disc of the electric brake device of the automobile is provided on the reciprocating member and the claw portion of the caliper facing the reciprocating member, and a braking force is applied to the automobile by the brushless motor 10.

As shown in FIG. 2, the rotor portion 18 has a larger diameter than the shaft portions 17a and 17b at both ends, and the outer peripheral surface 19 is a fitting surface. The ring magnet 31 is fixed to the outer peripheral surface 19 by the adhesive 26, the rotor 20 is formed by the rotor portion 18 of the shaft 16 and the ring magnet 31, and the rotor assembly 30 is formed by the shaft 16 and the ring magnet 31. .. The ring magnet 31 is formed by alternately magnetizing a cylindrical member made of a magnetic material with N poles and S poles as magnetic poles shifted in the circumferential direction. Therefore, the magnetic poles are magnetized on the ring magnet 31 in a state where the different polarities are adjacent to each other in the circumferential direction. As shown in FIG. 3, the ring magnet 31 is magnetized with 10 magnetic poles in the circumferential direction, and the rotor 20 has 10 poles. In FIG. 3, the boundary portion of the magnetic pole of the ring magnet 31 is shown by a broken line. As described above, the brushless motor 10 is a ring magnet type, and unlike the surface magnet type and the embedded magnet type rotors, the magnetic poles can be evenly allocated in the circumferential direction, and the rotor 20 can be assembled with a small number of man-hours. Can be manufactured. In a motor equipped with a surface magnet type rotor, it is conceivable that the arc-shaped magnet attached to the outer peripheral surface of the cylindrical member will come off, but the ring magnet type motor can improve its durability. can.

The stator 15 has a substantially cylindrical stator core 32, and the inner peripheral surface of the stator core 32 faces the outer peripheral surface of the ring magnet 31 through a gap. As shown in FIG. 3, the stator core 32 is formed by combining nine tooth portions 33 in the circumferential direction. Each tooth portion 33 is formed by laminating a plurality of metal plates (electromagnetic steel sheets) punched by press working. Each metal plate is provided with a through hole (not shown) for positioning during stacking. An insulator 34 made of an insulating resin material is attached to each tooth portion 33, and a coil 35 is wound around the outside of the insulator 34. A coil 35 is wound around the nine teeth portions 33, and the stator 15 shown in FIGS. 1 to 3 has nine coils 35.

Each coil 35 constitutes three phases of U phase, V phase, and W phase in order in the circumferential direction, and each phase is formed by the three coils 35. As shown in FIG. 2, the bus bar unit 36 is arranged on the end surface of the stator 15 on the distal end side. The bus bar unit 36 is provided with coil terminals 37 for each phase, and the coil terminals 37 are connected to an external power supply source. In FIG. 2, one of the three coil terminals 37 for three phases is shown.

A sensor disk 38 is attached to the shaft 16 and a magnet is provided on the sensor disk 38 in order to detect the position of the rotor 20 in the rotational direction. The sensor board 39 is attached to the bracket 13 facing the sensor disk 38, and a Hall element that responds to the magnetic force of the magnet provided on the sensor disk 38 is provided on the sensor board 39.

FIG. 4 is a block diagram showing a rotation control circuit of the motor. The rotation control circuit has three Hall elements 41a to 41c corresponding to the three-phase coil, and each Hall element is attached to the sensor substrate 39 shown in FIG. 2 as described above. Each of the Hall elements 41a to 41c detects the magnetic flux of the magnet provided on the sensor disk 38, and outputs a detection signal when the polarity of the magnetic pole portion of the rotor 20 changes from the N pole to the neutral point of the S pole. It is a magnetic field detection element as a detection sensor that outputs. The position of the rotor 20 is detected based on the detection signal from the Hall element, and the energization switching operation for each coil 35 is performed. The sensor for detecting the rotation 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 rotation control circuit of the motor includes an inverter circuit 42 for controlling the drive current for each of the U-phase, V-phase, and W-phase coils 35. The inverter circuit 42 is a three-phase full-bridge inverter circuit, and has two switching elements T1 and T2 connected in series, two switching elements T3 and T4, and two switching elements T5 and T6, respectively. Each is connected to the output terminals of the positive electrode and the negative electrode of the DC power supply 43. One coil terminal of the U-phase coil 35 is connected between the two switching elements T1 and T2. One coil terminal of the V-phase coil 35 is connected between the two switching elements T3 and T4. One coil terminal of the W phase coil 35 is connected between the two switching elements T5 and T6. The other coil terminals of the U-phase, V-phase, and W-phase coils 35 are connected to each other, and each coil 35 has a star connection. The connection method may be a delta connection. By adjusting the timing of the control signal supplied to each switching element, electric power is applied to the coil 35 to control the commutation operation for each coil 35.

The rotation control circuit of the motor has a controller 44, and a control signal is sent from the controller 44 to the inverter circuit 42 via the control signal output circuit 45. The detection signals of the Hall elements 41a to 41c as the rotation position detection sensor are sent to the rotor position detection circuit 46, and the signal is sent from the rotor position detection circuit 46 to the controller 44. The controller 44 has a microprocessor that calculates a control signal and a memory that stores a control program, data, and the like.

The inverter circuit 42, the controller 44, the rotor position detection circuit 46, and the like are provided outside the motor, and power is supplied to the coils of each phase from the inverter circuit 42. Further, the detection signals from the plurality of Hall elements 41a to 41c are sent to the external rotor position detection circuit 46. Electric power is supplied to each of the Hall elements 41a to 41c from the outside. The bracket 13 is provided with a connector 47, and power is supplied to each coil 35 by a plug connected to the connector 47.

FIG. 5 is an enlarged cross-sectional view showing a rotor assembly 30 including the shaft 16 and the ring magnet 31 shown in FIG.

A flange portion, that is, a flange 51 is provided on the shaft portion 17b of the shaft 16, and a region of the shaft 16 between the flange 51 and the shaft portion 17a is a rotor portion 18. The ring magnet 31 is composed of two magnet members 31a and 31b, and the end surface 52 of the magnet member 31a is abutted against the flange 51. Assuming that the output end side of the shaft 16 is the tip end portion, the magnet member 31a is the first magnet member on the tip end side, and the magnet member 31b is the second magnet member on the base end side. The end surface on the opposite side of the end surface 52 of the magnet member 31a on the distal end side is the facing surface 53, and the facing surface 54 of the magnet member 31b on the proximal end side is abutted against the facing surface 53.

The flange 51 has a stopper portion 56, and the stopper portion 56 is abutted against the radial inner portion 55 of the end surface 52 of the ring magnet 31. The flange 51 has a large diameter portion 57 having a diameter larger than that of the stopper portion 56, and the large diameter portion 57 forms an adhesive storage groove 58 with the end face 52 on the radial outer side of the stopper portion 56. An adhesive storage recess 59 is provided on the outer peripheral surface 19 of the rotor portion 18 adjacent to the stopper portion 56, and the adhesive storage recess 59 is connected adjacent to the adhesive storage groove 58.

To attach the ring magnet 31 to the outer peripheral surface 19, the ring magnet 31 is moved toward the flange 51 with the adhesive 26 applied to the outer peripheral surface 19. At this time, the adhesive 26 is partially scraped off from the end surface 52 of the ring magnet 31, and the adhesive 26 partially protrudes from the end surface 52. When the end surface 52 is abutted against the stopper portion 56, the protruding adhesive 26 is accommodated in the adhesive storage groove 58 formed between the end surface 52 and the large diameter portion 57. This prevents the adhesive 26 from squeezing out of the ring magnet 31 in the radial direction.

7 (A) to 7 (C) are process diagrams showing a process of assembling the ring magnet 31 to the outer peripheral surface 19 of the shaft 16. In FIG. 5, the adhesive 26 is shown in the portion inserted between the outer peripheral surface 19 and the ring magnet 31, whereas in the process diagram, the adhesive 26 is applied to the entire outer peripheral surface 19 applied. It is shown.

As shown in FIG. 5, in order to attach the ring magnet 31 composed of the two magnet members 31a and 31b to the outer peripheral surface 19 of the rotor portion 18, as shown in FIG. 7A, the ring magnet 31 is attached to the tip of the outer peripheral surface 19. The adhesive 26 is applied in layers. Under this state, the magnet member 31a is fitted to the rotor portion 18 from the base end portion of the shaft 16 and is moved toward the flange 51. FIG. 7B shows the magnet member 31a in the middle of moving toward the flange 51, and the adhesive 26 enters between the inner peripheral surface of the magnet member 31a and the outer peripheral surface 19 of the rotor portion 18 and is partially formed. The adhesive squeezes out onto the end face 52. The protruding adhesive 26 first enters the adhesive reservoir recess 59, and is pushed toward the large diameter portion 57 by the subsequent movement of the magnet member 31a. At this time, the adhesive 26 in the adhesive reservoir recess 59 is pushed forward toward the radial outer peripheral portion side of the large diameter portion 57. As a result, when the radial inner portion 55 of the end surface 52 is abutted against the stopper portion 56 and the adhesive 26 is pushed into the adhesive reservoir 58 formed between the large diameter portion 57 and the end surface 52, The adhesive 26 is prevented from squeezing out of the end face 52 in the radial direction. The stopper portion 56 may be provided with a plurality of notches for communicating the adhesive reservoir recess 59 and the adhesive reservoir groove 58.

FIG. 7C shows a state in which the radial inner peripheral portion of the end surface 52 is abutted against the stopper portion 56. As shown in the figure, the adhesive 26 protruding from the end surface 52 is housed in the adhesive storage groove 58 formed between the end surface 52 and the large diameter portion 57 facing the end surface 52, so that the outside of the magnet member 31a The adhesive 26 is prevented from squeezing out toward the side. This eliminates the need to wipe off the adhesive that protrudes outward in the radial direction of the end face 52, and improves the workability of assembling the ring magnet 31 to the shaft 16.

After the magnet member 31a on the distal end side is attached to the outer peripheral surface 19, the magnet member 31b on the proximal end side is fitted to the proximal end portion of the shaft 16 and abutted against the magnet member 31a. In this way, as shown in FIG. 5, the ring magnet 31 composed of the two magnet members 31a and 31b is fitted to the outer peripheral surface 19 of the rotor portion 18 and fixed to the outer peripheral surface 19 by the adhesive 26.

FIG. 6A is an enlarged cross-sectional view of part A shown in FIG. FIG. 6B is a cross-sectional view of a portion of a brushless motor as a comparative example similar to that of FIG. 6A, and the adhesive reservoir 58 is not provided in the comparative example. In FIG. 6, the stator core 32 is shown by a two-dot chain line, and the magnetic flux generated between the ring magnet 31 and the stator core 32 is shown by a broken line.

As shown in FIG. 6A, when the adhesive reservoir groove 58 is provided between the end surface 52 of the ring magnet 31 and the large diameter portion 57, the adhesive at the step portion between the end surface 52 and the large diameter portion 57 is provided. The density of the magnetic flux generated in the reservoir 58 becomes high, and the flow of the magnetic flux returning from the flange portion, that is, the large diameter portion 57 to the stator core 32 becomes weak. As shown in the comparative example of FIG. 6B, when the end surface 52 of the ring magnet 31 is abutted against the flange 51, the step becomes zero. As a result, a magnetic flux flowing from the flange 51 to the stator core 32 is generated, and the magnetic flux density at the end of the stator core 32 becomes low. That is, when the adhesive storage groove 58 is provided, the magnetic flux, that is, the magnetic path guided there is generated. Therefore, as shown by the arrows in FIGS. 6A and 6B, when the stepped portion is provided as compared with the case where the flange 51 is abutted on the entire end surface 52, the large diameter portion 57 returns to the stator core 32. The magnetic flux becomes weak, and as a result, the density of the magnetic flux at the end of the stator core 32 does not decrease, and the density can be increased.

Further, as shown in FIG. 6A, when a step for the adhesive storage groove 58 is provided between the end surface 52 of the ring magnet 31 and the large diameter portion 57, the magnetic flux straight from the ring magnet 31 to the stator core 32. Flows. On the other hand, as shown in FIG. 6B, when the end surface 52 of the ring magnet 31 is abutted against the flange 51, magnetic flux flows diagonally from the ring magnet 31 toward the stator core 32. Therefore, if the adhesive reservoir 58 is provided and a step is provided between the flange 51 and the ring magnet 31, as a result, the decrease in the magnetic flux density at the end of the stator core 32 can be suppressed and the density can be increased.

It was confirmed by experiments that the induced voltage can be increased when a step is provided between the end face 52 and the large diameter portion 57 than when the step is set to zero.

FIG. 8 is a cross-sectional view showing a rotor assembly 30 according to another embodiment. The rotor assembly 30 of FIG. 8 is composed of a ring magnet 31 and a shaft 16 made of a single magnet member, and the rotor 20 is composed of a rotor portion 18 of the shaft 16 and a ring magnet 31. The shaft 16 is the same as that shown in FIGS. 5 and 6, and the flange 51 has a stopper portion 56 and a large diameter portion 57, and is adhered between the end surface 52 of the ring magnet 31 and the large diameter portion 57. The agent reservoir 58 is formed. Therefore, the rotor assembly 30 can be assembled by mounting the ring magnet 31 made of a single magnet member on the outer peripheral surface 19 of the shaft 16. Also in this form of the rotor assembly 30, it is possible to prevent the adhesive 26 from sticking out, improve the assembly workability, and suppress the decrease in the magnetic flux density.

FIG. 9 is a cross-sectional view showing a rotor assembly 30 according to still another embodiment, and FIG. 10 is a process diagram showing a process of assembling the ring magnet 31 to the outer peripheral surface 19 of the shaft 16 shown in FIG. ..

The rotor assembly 30 shown in FIG. 9 is composed of a ring magnet 31 composed of two magnet members 31a and 31b and a shaft 16, and the rotor 20 is composed of a rotor portion 18 of the shaft 16 and a ring magnet 31.

The shaft 16 has a flange 51, and the flange 51 faces the end surface 52 of the magnet member 31a on the distal end side and is abutted against the flange 51. The facing surface 54 of the magnet member 31b on the base end side faces and abuts against the facing surface 53 composed of the end faces on the opposite side of the end face 52. An adhesive reservoir groove 58 is formed on the outer peripheral surface 19 of the rotor portion 18 of the shaft 16 so as to correspond to both the facing surfaces 53 and 54. The adhesive storage groove 58 has a predetermined width dimension in the axial direction of the shaft 16 with the positions of the facing surfaces 53 and 54 as the center, and is formed by cutting a part of the outer peripheral surface 19.

FIG. 10A shows a state in which the magnet member 31a is attached to the outer peripheral surface 19 and the end surface 52 is abutted against the flange 51 under the state where the adhesive 26 is applied to the tip region of the outer peripheral surface 19. Is shown. The shaft 16 is formed with an adhesive storage recess 59 adjacent to the flange 51, and when the end face 52 is abutted against the flange 51, the adhesive 26 is housed in the adhesive storage recess 59.

FIG. 10B shows a state in which the adhesive 26 is applied to the base end side region of the outer peripheral surface 19. Under this state, the magnet member 31b on the proximal end side is fitted to the outer peripheral surface 19 of the rotor portion 18 and inserted toward the magnet member 31a. At this time, the adhesive 26 protruding from the facing surface 54 of the magnet member 31b is supplied to the adhesive storage groove 58 by the facing surface 54 as the magnet member 31b moves. As a result, as shown in FIG. 9, the adhesive 26 is prevented from protruding to the outside of the ring magnet 31, and the workability of assembling the ring magnet 31 to the shaft 16 can be improved.

FIG. 11 is a cross-sectional view showing a rotor assembly according to still another embodiment, and FIG. 12 is a process diagram showing a process of assembling the ring magnet 31 to the outer peripheral surface 19 of the shaft 16 shown in FIG. ..

The rotor assembly 30 shown in FIG. 11 is composed of a ring magnet 31 composed of two magnet members 31a and 31b and a shaft 16 in the same manner as the rotor assembly 30 shown in FIG.

The rotor assembly 30 has a spacer ring 61 mounted on the outer peripheral surface 19 of the rotor portion 18. As shown in FIG. 11, the spacer ring 61 has an inner surface 62 having a diameter slightly larger than that of the outer peripheral surface 19, and the outer diameter is larger than the inner diameter of the ring magnet 31. The shaft 16 is the same as that shown in FIG. 9, and has a flange 51 facing the end surface 52 of the magnet member 31a on the distal end side and contacting the end surface 52. When one end surface of the spacer ring 61 is abutted against the radial inner portion of the facing surface 53 of the magnet member 31a and the radial inner portion of the facing surface 54 of the magnet member 31b is abutted against the other end surface, the diameter of the spacer ring 61 is formed. An adhesive reservoir 58 is formed between the facing surfaces 53 and 54, which is outward in the direction. Since the adhesive 26 is accommodated in the adhesive reservoir 58, it is prevented that the adhesive 26 protrudes to the outside of the ring magnet 31.

FIG. 12A shows a state in which the magnet member 31a is attached to the outer peripheral surface 19 and the end surface 52 is abutted against the flange 51 under the state where the adhesive 26 is applied to the tip region of the outer peripheral surface 19. Is shown. The shaft 16 is formed with an adhesive storage recess 59 adjacent to the flange 51, and when the end face 52 is abutted against the flange 51, the adhesive 26 is housed in the adhesive storage recess 59. After the magnet member 31a is mounted, the spacer ring 61 is fitted to the outer peripheral surface 19 from the base end side of the shaft 16, is moved toward the facing surface 53 of the magnet member 31a, and is abutted against the facing surface 53.

Next, as shown in FIG. 12B, the adhesive 26 is applied to the base end side region of the outer peripheral surface 19. Under that state, the magnet member 31b on the proximal end side is fitted to the outer peripheral surface 19 of the rotor portion 18 and moved toward the spacer ring 61. At this time, the adhesive 26 protruding from the facing surface 54 of the magnet member 31b is moved toward the facing surface 53 of the magnet member 31a by the facing surface 54 as the magnet member 31b moves. When the facing surface 54 of the magnet member 31b is abutted against the spacer ring 61, an adhesive storage groove 58 is formed radially outward of the spacer ring 61 between the facing surfaces 53 and 54. Therefore, the adhesive 26 protruding from the facing surface 54 is housed in the adhesive storage groove 58. As a result, the adhesive 26 is prevented from protruding to the outside of the ring magnet 31, and the workability of assembling the ring magnet 31 to the shaft 16 can be improved.

The shaft 16 shown in FIGS. 9 and 11 may also be a shaft 16 in which a stopper portion 56 and a large diameter portion 57 are provided on the flange 51, as shown in FIGS. 5 and 8, in which case the above-mentioned shaft 16 may be used. As described above, the adhesive 26 is accommodated in the adhesive reservoir groove 58 and the adhesive reservoir recess 59.

FIG. 13 is a cross-sectional view of a brushless motor according to another embodiment, and shows a portion similar to that of FIG.

In the brushless motor 10, a cylindrical rotor core 27 is mounted on the outside of the rotor portion 18 of the shaft 16. The rotor core 27 is formed by laminating a plurality of metal plates, that is, electromagnetic steel sheets, which are punched out in a substantially annular shape by press working. Each electrical steel sheet is provided with a through hole 28 for weight reduction. As described above, in the brushless motor provided with the rotor core 27, the ring magnet 31 is fixed to the outer peripheral surface 19 of the rotor core 27 by the adhesive 26.

Also in the brushless motor 10 provided with the rotor core 27, as shown in FIG. 5, a stopper portion 56 and a large diameter portion 57 are provided on the flange 51, and an adhesive 26 is formed between the end face 52 and the large diameter portion 57. There is a form in which the adhesive is housed in the adhesive storage groove 58. Also in this form of the brushless motor, there are a form in which the ring magnet 31 is formed by a single member and a form in which the ring magnet 31 is formed by two magnet members.

In the brushless motor 10 shown in FIG. 13, as shown in FIG. 9, a ring magnet 31 is formed by a first magnet member 31a and a second magnet member 31b, and both magnet members 31a and 31b face each other. There is a form in which an adhesive storage groove 58 is formed on the outer peripheral surface 19 of the rotor core 27 so as to correspond to the surface, and the adhesive 26 is housed in the adhesive storage groove 58. Further, as shown in FIG. 11, a spacer ring 61 is arranged between both magnet members 31a and 31b, and is radially outward of the spacer ring 61 and adheres between both magnet members 31a and 31b. There is a form in which the agent reservoir 58 is formed.

As described above, in each of the brushless motors 10 in which the ring magnet 31 is fixed to the outer peripheral surface 19 of the rotor portion 18 of the shaft 16 or the outer peripheral surface 19 of the rotor core 27 by the adhesive 26, the ring magnet 31 is adhered to the outer peripheral surface 19. When the ring magnet 31 is assembled via the agent 26, the adhesive is prevented from squeezing out to the outside of the ring magnet 31. As a result, the work of wiping off the adhesive becomes unnecessary, and the workability of assembling the ring magnet 31 to the shaft 16 can be improved.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the gist thereof. For example, not only when the ring magnet 31 is formed by a brushless motor formed by a single magnet member as shown in FIG. 8 and by two magnet members as shown in FIG. 5, but also by two or more magnets. The present invention can also be applied to a brushless motor in which a ring magnet is formed by a member.

10: Brushless motor, 11: Motor case, 15: Stator, 16: Shaft, 17a, 17b: Shaft, 18: Rotor, 19: Outer surface, 20: Rotor, 26: Adhesive, 27: Rotor core, 30: Rotor assembly, 31: ring magnet, 31a, 31b: magnet member, 32: stator core, 33: teeth part, 34: insulator, 51: flange, 52: end face, 53, 54: facing surface, 55: radial inner part , 56: Stopper portion, 57: Large diameter portion, 58: Adhesive reservoir groove, 59: Adhesive reservoir recess, 61: Spacer ring.

Claims (6)

With the stator,
A shaft portion provided with a flange and a rotor portion provided integrally with the shaft portion and arranged inside the stator, and a shaft rotatably supported by the shaft.
It has a ring magnet fixed to the outer peripheral surface of the rotor portion or the outer peripheral surface of the rotor core mounted on the outside of the rotor portion by an adhesive.
The flange is provided with a stopper portion that is abutted against the radial inner portion of the end surface of the ring magnet and a large diameter portion that faces the end surface of the ring magnet and forms an adhesive reservoir groove.
A brushless motor that accommodates the adhesive protruding from the end face in the adhesive reservoir groove when the ring magnet is moved toward the flange. In the brushless motor according to claim 1,
The ring magnet is a brushless motor composed of a single magnet member or at least two magnet members. In the brushless motor according to claim 1 or 2.
The adhesive reservoir is a brushless motor that guides the magnetic flux between the ring magnet and the stator. With the stator,
A shaft portion provided with a flange and a rotor portion provided integrally with the shaft portion and arranged inside the stator, and a shaft rotatably supported by the shaft.
It has a ring magnet fixed to the outer peripheral surface of the rotor portion or the outer peripheral surface of the rotor core mounted on the outside of the rotor portion by an adhesive.
The ring magnet includes a first magnet member provided with an end surface facing the flange, and a second magnet member provided with an facing surface facing the facing surface of the first magnet member.
An adhesive reservoir groove is formed on the outer peripheral surface so as to correspond to the facing surface of the first magnet member and the second magnet member.
A brushless motor that accommodates the adhesive that has squeezed out from the facing surface into the adhesive reservoir when the second magnet member is moved toward the first magnet member. With the stator,
A shaft portion provided with a flange and a rotor portion provided integrally with the shaft portion and arranged inside the stator, and a shaft rotatably supported by the shaft.
A ring magnet fixed with an adhesive to the outer peripheral surface of the rotor portion or the outer peripheral surface of the stator core arranged outside the rotor portion.
The ring magnet includes a first magnet member provided with an end surface facing the flange, and a second magnet member provided with an facing surface facing the facing surface of the first magnet member.
It is positioned between the facing surface of the first magnet member and the facing surface of the second magnet member and mounted on the outer peripheral surface to form an adhesive reservoir groove between both facing surfaces. With a spacer ring,
A brushless motor that accommodates the adhesive that has squeezed out from the facing surface into the adhesive reservoir when the second magnet member is moved toward the first magnet member. In the brushless motor according to claim 4 or 5.
The flange is provided with a stopper portion that is abutted against the radial inner portion of the end surface of the ring magnet and a large diameter portion that faces the end surface of the ring magnet and forms an adhesive reservoir groove.
A brushless motor that accommodates the adhesive protruding from the end face in the adhesive reservoir groove when the ring magnet is moved toward the flange.

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