JP2021058000A - Motor and transmission device - Google Patents

Abstract

To provide a motor which secures strength and achieves reduction of the weight.SOLUTION: A motor includes a stator, a rotor, a housing, a bus bar, a bus bar holder, and a cover 26. The housing is a member which houses the stator and the rotor and has a bottomed cylindrical shape. The bus bar is electrically connected to a conductive wire pulled out upward from the stator. The bus bar holder is disposed at an upper part of the housing and retains the bus bar. The cover is made of a resin and has ribs 80 protruding downward from a top plate part. The ribs include an annular ribs 81 and radial ribs 82 extending from the annular rib to the radial outer side.SELECTED DRAWING: Figure 6

Description

The present invention relates to motors and transmission devices.

Conventionally, various motors are mounted on transportation equipment such as automobiles. For example, Japanese Patent Application Laid-Open No. 2016-34203 describes a motor that outputs steering assist torque of an electric power steering device.
Japanese Unexamined Patent Publication No. 2016-34203

In this type of motor, the stator and rotor are often housed inside a housing consisting of a metal housing and a metal cover. However, the use of metal housings and covers increases the weight of the motor.

In order to reduce the weight of the motor, for example, it is conceivable to change the material of the cover from metal to resin. However, the resin cover has a problem that the strength against an external force is lower than that of the metal cover. In particular, in an in-vehicle motor, the cover is also required to have sufficient strength in preparation for contact with flying stones.

An object of the present invention is to provide a motor capable of reducing the weight of the motor and ensuring the strength of the cover.

The present invention is a motor, an annular stator centered on a vertically extending central axis, a rotor rotatably supported around the central axis inside the stator in the radial direction, the stator, and the above. A bottomed tubular housing that houses the rotor, a metal bus bar that is electrically connected to a wire drawn upward from the stator, and a bus bar that is located above the housing and holds the bus bar. A holder and a cover made of resin are provided, and the cover has a top plate portion that covers the upper portion of the bus bar holder, and a plurality of ribs that project downward from the top plate portion. Ribs include an annular rib in a bottom view and a plurality of radial ribs extending radially outward from the annular rib.

According to the present invention, the weight of the motor can be reduced by making the cover made of resin. In addition, the annular rib and the plurality of radial ribs improve the strength of the cover. That is, it is possible to achieve both the weight reduction of the motor and the securing of the strength of the cover.

FIG. 1 is a perspective view of the motor. FIG. 2 is a perspective view of the motor. FIG. 3 is a top view of the motor. FIG. 4 is a vertical cross-sectional view of the motor. FIG. 5 is a vertical cross-sectional view of the cover. FIG. 6 is a perspective view seen from the diagonally lower side of the cover. FIG. 7 is a bottom view of the cover. FIG. 8 is a vertical cross-sectional view of the cover according to the first modification. FIG. 9 is a side view of the cover according to the second modification. FIG. 10 is a side view of the cover according to the third modification.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings. In the present application, the direction parallel to the central axis of the motor is the "axial direction", the direction orthogonal to the central axis of the motor is the "radial direction", and the direction along the arc centered on the central axis of the motor is the "circumferential direction". , Each. Further, in the present application, the shape and positional relationship of each part will be described with the axial direction in the vertical direction and the cover side facing up with respect to the housing. However, this definition of the vertical direction does not intend to limit the orientation of the motor according to the present invention during manufacturing and use.

Further, the above-mentioned "parallel direction" also includes a substantially parallel direction. Further, the above-mentioned "orthogonal direction" includes a direction substantially orthogonal to each other.

<1. Overall configuration of motor>
1 and 2 are perspective views of the motor 1 according to the embodiment of the present invention. FIG. 3 is a top view of the motor 1. FIG. 4 is a vertical cross-sectional view of the motor 1. Note that FIG. 4 is a cross-sectional view taken along the line AA in FIG.

This motor 1 is mounted on an automobile, for example, and is used as a drive source for generating a driving force of a transmission device. In FIG. 1, the transmission device 100 on which the motor 1 is mounted is conceptually shown by a chain double-dashed line. As shown in FIG. 1, the motor 1 is attached to the side portion of the transmission device 100 in a posture in which the cover 26 described later is on the outside.

However, the motor of the present invention may be used for applications other than the transmission device. For example, the motor of the present invention may be used as a drive source for other parts of an automobile, such as an electric power steering device, a braking device, an engine cooling fan, or an oil pump. Further, the motor of the present invention may be mounted on home appliances, OA equipment, medical equipment and the like to generate various driving forces.

As shown in FIG. 4, the motor 1 has a stationary portion 2 and a rotating portion 3. The stationary portion 2 is fixed to the frame of the device to be driven. The rotating portion 3 is rotatably supported with respect to the stationary portion 2.

The stationary portion 2 of the present embodiment includes a stator 21, a housing 22, a plurality of bus bars 23, a bus bar holder 24, a circuit board 25, a cover 26, a lower bearing 27, an upper bearing 28, and an oil seal 29.

The stator 21 is an armature that generates a rotating magnetic field according to a driving current. The stator 21 has an annular outer shape centered on the central axis 9. The stator 21 has a stator core 41, a plurality of insulators 42, and a plurality of coils 43.

The stator core 41 is made of laminated steel plates in which electromagnetic steel plates are laminated in the axial direction. The stator core 41 has an annular core back 411 and a plurality of teeth 412 protruding inward in the radial direction from the core back 411. The core back 411 is arranged substantially coaxially with the central axis 9. The plurality of teeth 412 are arranged at substantially equal intervals in the circumferential direction.

The insulator 42 is made of a resin which is an insulator. At least a part of the surface of the stator core 41 is covered with the insulator 42. Specifically, of the surface of the stator core 41, at least the upper surface, the lower surface, and both end surfaces in the circumferential direction of each tooth 412 are covered with the insulator 42.

The coil 43 is composed of a wire wound around the insulator 42. That is, in the present embodiment, the lead wire is wound around the teeth 412, which is the magnetic core, via the insulator 42. The insulator 42 prevents the teeth 412 and the coil 43 from being electrically short-circuited by interposing between the teeth 412 and the coil 43.

The housing 22 is a bottomed tubular metal member. The housing 22 is obtained, for example, by pressing a metal plate such as aluminum or stainless steel. The stator 21 and the rotor 32, which will be described later, are housed inside the housing 22. As shown in FIG. 1, the housing 22 has a bottom plate portion 51, a stator holding portion 52, a flange portion 55, and a lower cylinder portion 58.

The bottom plate portion 51 extends substantially perpendicular to the central axis 9 below the stator 21 and the rotor 32. The stator holding portion 52 extends in a cylindrical shape from the radial outer end portion of the bottom plate portion 51 toward the upper side. The stator core 41 is fixed to the inner peripheral surface of the stator holding portion 52. The flange portion 55 extends radially outward from the upper end portion of the stator holding portion 52. The lower cylinder portion 58 extends in a cylindrical shape from the radially inner end portion of the bottom plate portion 51 toward the lower side.

The plurality of bus bars 23 are metal members that supply a driving current to the coil 43 of the stator 21. Each of the plurality of bus bars 23 is obtained by pressing a metal piece which is a conductor. The end of the lead wire drawn upward from the coil 43 is electrically connected to the end of the bus bar 23, for example by welding.

The bus bar holder 24 is a resin member that holds a plurality of bus bars 23. The bus bar holder 24 is arranged on top of the housing 22. At least a part of each bus bar 23 is covered with the resin constituting the bus bar holder 24. The plurality of bus bars 23 are held by the bus bar holder 24 and kept apart from each other. This prevents the plurality of bus bars 23 from conducting each other.

The bus bar holder 24 has an inner plate-shaped portion 71, a tubular portion 72, an outer plate-shaped portion 73, a connector portion 74, and a support protrusion 75. The inner plate-shaped portion 71 extends substantially perpendicular to the central axis 9 above the stator 21 and the rotor 32. The bus bar 23 is held by the inner plate-shaped portion 71. An upper bearing holding member 76 for holding the upper bearing 28, which will be described later, is fixed to the radial inner end of the inner plate-shaped portion 71. The tubular portion 72 extends upward from the peripheral edge portion of the inner plate-shaped portion 71 in a tubular shape. The outer plate-shaped portion 73 extends radially outward from the lower end portion of the tubular portion 72. The connector portion 74 projects outward in the radial direction from a part of the outer peripheral surface of the tubular portion 72. The end portion of a part of the bus bar 23 is exposed to the outside in the connector portion 74. The support protrusion 75 projects upward in a columnar shape from the inner plate-shaped portion 71.

At the time of manufacturing the bus bar holder 24, first, a plurality of bus bars 23 and the upper bearing holding member 76 are arranged inside the mold. Then, the molten resin is poured into the mold to cure the molten resin. As a result, the bus bar holder 24 is molded, and the plurality of bus bars 23 and the upper bearing holding member 76 are fixed to the bus bar holder 24.

That is, the bus bar holder 24 is a resin molded product having a plurality of bus bars 23 and the upper bearing holding member 76 as insert parts. By molding a part of the bus bar 23 with resin, the waterproof property of the bus bar 23 can be improved.

The bus bar holder 24 is fixed to the housing 22 by crimping a part of the housing 22. Specifically, the housing 22 has a caulking piece 56 that further protrudes outward in the radial direction from a part of the collar portion 55. As shown in FIGS. 2 and 3, the caulking piece 56 is bent toward the upper surface side of the outer plate-shaped portion 73 of the bus bar holder 24. As a result, the bus bar holder 24 is fixed to the housing 22.

Further, as shown in FIG. 4, this motor 1 has an O-ring 57. The O-ring 57 is an annular sealing member. Elastic rubber is used as the material of the O-ring 57. The O-ring 57 is interposed between the upper surface of the flange portion 55 of the housing 22 and the lower surface of the outer plate-shaped portion 73 of the bus bar holder 24, and is compressed in the axial direction. As a result, the gap between the flange portion 55 and the outer plate-shaped portion 73 is sealed. As a result, water droplets are prevented from entering the inside of the motor 1 from between the flange portion 55 and the outer plate-shaped portion 73.

The circuit board 25 is an electric circuit board for supplying a drive current to the bus bar 23. The circuit board 25 is located above the bus bar 23 and the bus bar holder 24, and below the top plate portion 261 of the cover 26 described later. The circuit board 25 is supported by the support protrusions 75 of the bus bar holder 24. The end of the bus bar 23 is electrically connected to the electrical circuit on the circuit board 25. The circuit board 25 generates a drive current by the electric power supplied from the external power source. The generated drive current flows from the circuit board 25 through the bus bar 23 to the coil 43.

The cover 26 is a resin member that covers the upper part of the bus bar holder 24. By making the cover 26 made of resin, the weight of the cover 26 can be reduced as compared with the case where a metal cover is used. As shown in FIG. 1, the cover 26 of the present embodiment has a top plate portion 261, a peripheral wall portion 262, and a flange portion 263. The top plate portion 261 is a flat plate-shaped portion that extends perpendicularly to the central axis 9. The peripheral wall portion 262 extends downward from the peripheral edge portion of the top plate portion 261 in a tubular shape. The flange portion 263 extends radially outward from the lower end portion of the peripheral wall portion 262.

When assembling the motor 1, the flange portion 263 of the cover 26 is laser welded to the upper end portion of the tubular portion 72 of the bus bar holder 24. As a result, the cover 26 is fixed to the bus bar holder 24. Further, laser welding forms an annular welded portion that is continuous in the circumferential direction. As a result, it is possible to prevent water droplets from entering the inside of the motor 1 from between the bus bar holder 24 and the cover 26.

As shown in FIGS. 3 and 4, the cover 26 has two cover protrusions 264. The two cover protrusions 264 project downward from the lower surface of the flange portion 263. Each cover protrusion 264 contacts the inner peripheral surface of the upper end portion of the tubular portion 72 of the bus bar holder 24. As a result, the cover 26 is positioned with respect to the bus bar holder 24. The cover protrusion 264 may come into contact with the outer peripheral surface of the upper end portion of the tubular portion 72.

The cover 26 also has a notch 265. The notch 265 is recessed inward in the radial direction from a part of the outer peripheral portion of the flange portion 263. On the other hand, the bus bar holder 24 has a holder protrusion 77. The holder protrusion 77 extends upward from the upper surface of the connector portion 74. Then, the holder protrusion 77 is inserted into the notch 265 described above. As a result, the cover 26 is positioned with respect to the bus bar holder 24.

The cover protrusion 264 may be provided at any position in the circumferential direction. Further, the cover protrusion 264 may be provided in an annular shape along the upper end portion of the tubular portion 72. Further, the cover protrusion 264 may be provided so as to come into contact with the outer peripheral surface of the upper end portion of the tubular portion 72. Further, the notch 265 and the holder protrusion 77 may be provided at a plurality of positions in the circumferential direction. Further, the structure may be such that a through hole is provided instead of the notch 265 and the holder protrusion 77 is inserted into the through hole. Further, either one of the cover protrusion 264, the notch 265 and the holder protrusion 77 may be omitted.

The lower bearing 27 and the upper bearing 28 are arranged between the housing 22 and the bus bar holder 24 and the shaft 31 on the rotating portion 3 side. The lower bearing 27 is located below the rotor 32, which will be described later. The upper bearing 28 is located above the rotor 32 described later.

For the lower bearing 27 and the upper bearing 28, for example, a ball bearing that relatively rotates the outer ring and the inner ring via a plurality of spheres is used. The outer ring of the lower bearing 27 is fixed to the lower cylinder portion 58 of the housing 22. The outer ring of the upper bearing 28 is fixed to the upper bearing holding member 76 held by the bus bar holder 24. Further, each inner ring of the lower bearing 27 and the upper bearing 28 is fixed to the shaft 31. As a result, the shaft 31 is rotatably supported with respect to the housing 22. However, instead of ball bearings, bearings of other types such as slide bearings and fluid bearings may be used.

The oil seal 29 is a member for preventing water droplets or oil droplets from entering the inside of the housing 22 from between the housing 22 and the shaft 31. The oil seal 29 is located below the lower bearing 27. The shape of the oil seal 29 is an annular shape centered on the central axis 9. The outer peripheral surface of the oil seal 29 is fixed to the lower cylinder portion 58 of the housing 22. The inner peripheral surface of the oil seal 29 comes into contact with the outer peripheral surface of the shaft 31.

The rotating portion 3 of the present embodiment has a shaft 31 and a rotor 32.

The shaft 31 is a columnar member extending along the central axis 9. As the material of the shaft 31, for example, a metal such as stainless steel is used. The shaft 31 rotates about the central axis 9 while being supported by the lower bearing 27 and the upper bearing 28 described above. Further, the lower end portion 311 of the shaft 31 projects downward from the bottom plate portion 51 of the housing 22. A device to be driven is connected to the lower end portion 311 of the shaft 31 via a power transmission mechanism such as a gear. The shaft 31 does not necessarily have to project downward from the housing 22. That is, the cover 26 may be provided with a through hole, and the upper end portion of the shaft 31 may protrude upward from the cover 26 through the through hole. Further, the shaft 31 may be a hollow member. When the shaft 31 is a hollow member, the lower end of the shaft 31 does not have to protrude downward from the housing 22, and the upper end of the shaft 31 does not have to protrude upward from the cover 26.

The rotor 32 is located inside the stator 21 in the radial direction, and rotates around the central axis 9 together with the shaft 31. The rotor 32 has a rotor core 61 and a plurality of magnets 62. The rotor core 61 is made of a laminated steel plate in which electromagnetic steel plates are laminated in the axial direction. The rotor core 61 has a through hole 60 extending in the axial direction in the center thereof. The shaft 31 is press-fitted into the through hole 60 of the rotor core 61. As a result, the rotor core 61 and the shaft 31 are fixed to each other.

The plurality of magnets 62 are fixed to the outer peripheral surface of the rotor core 61 with, for example, an adhesive. The radial outer surface of each magnet 62 is a magnetic pole surface facing the radial inner end surface of the teeth 412. The plurality of magnets 62 are arranged in the circumferential direction so that the north pole and the south pole are alternately arranged. Instead of the plurality of magnets 62, one annular magnet in which the north pole and the south pole are alternately magnetized in the circumferential direction may be used. Further, the plurality of magnets 62 may be embedded inside the rotor core 61.

When a drive current is supplied from the circuit board 25 to the coil 43 via the bus bar 23, a rotating magnetic field is generated in the plurality of teeth 412 of the stator core 41. Then, torque in the circumferential direction is generated by the magnetic attraction force and repulsion force between the teeth 412 and the magnet 62. As a result, the rotating portion 3 rotates about the central axis 9 with respect to the stationary portion 2.

<2. About the shape of the underside of the cover>
Subsequently, the shape of the lower surface of the cover 26 described above will be described. FIG. 5 is a vertical cross-sectional view of the cover 26. FIG. 6 is a perspective view seen from the diagonally lower side of the cover 26. FIG. 7 is a bottom view of the cover 26.

As shown in FIGS. 5 to 7, the cover 26 has a plurality of ribs 80. The plurality of ribs 80 project downward from the top plate portion 261. The axial thickness from the upper surface of the top plate portion 261 to the lower end portion of the rib 80 is larger than the axial thickness of the portion of the top plate portion 261 without the rib 80.

As shown in FIGS. 6 and 7, the plurality of ribs 80 include one annular rib 81 and a plurality of radial ribs 82. The shape of the annular rib 81 is annular in the bottom view. The center of the annular rib 81 is located on the central axis 9. As a result, the radial length of the top plate portion 261 around the annular rib 81 becomes non-uniform. As a result, the resonance of the top plate portion 261 is suppressed. The plurality of radial ribs 82 extend radially outward from the annular ribs 81. The width near the lower end of each of the ribs 81 and 82 gradually narrows toward the bottom. As a result, the cover 26 can be easily taken out from the mold after the cover 26 is molded.

In the present embodiment, the weight of the motor 1 is reduced by making the cover 26 made of resin. Further, by providing the annular rib 81 and the plurality of radial ribs 82, the strength of the cover 26 is improved as compared with the case where these ribs 81 and 82 are not provided. Therefore, even if the stepping stones come into contact with the cover 26, damage to the cover 26 due to an external force received from the stepping stones can be suppressed. That is, according to the structure of the present embodiment, it is possible to achieve both the weight reduction of the motor 1 and the securing of the strength of the cover 26.

In the present embodiment, a plurality of radial ribs 82 are provided at equal angular intervals in the circumferential direction. By doing so, it is easy to evenly flow the molten resin into the mold when the cover 26 is molded. Therefore, shape defects are unlikely to occur in the plurality of ribs 80. As a result, the reinforcing effect of the cover 26 by the rib 80 can be obtained more reliably.

Further, as shown in FIGS. 6 and 7, the lower surface of the cover 26 has a plurality of recesses 90. The plurality of recesses 90 include one central recess 91 and a plurality of outer recesses 92. The central recess 91 is a portion of the lower surface of the cover 26 surrounded by the annular rib 81. The outer recess 92 is a portion of the lower surface of the cover 26 located on the radial outer side of the annular rib 81 and between the adjacent radial ribs 82.

If the difference in area between the plurality of recesses 90 is large, the reinforcing effect of the rib 80 will be biased. Therefore, in the present embodiment, the radius of the annular rib 81 is set to an appropriate size that is larger than the radius of the shaft 31 and smaller than the radius of the rotor 32. As a result, the difference in area between the plurality of recesses 90 is reduced. In this way, the reinforcing effect of the cover 26 by the rib 80 can be further enhanced.

Further, in the present embodiment, in the bottom view, the area S0 of the central recess 91 is larger than the area S1 of the smallest outer recess 92 among the plurality of outer recesses 92, and is larger than the area S2 of the largest outer recess 92. Is also small. In this way, the difference in area between the central recess 91 and the outer recess 92 can be made smaller. As a result, the reinforcing effect of the cover 26 by the rib 80 can be further enhanced.

Further, in the present embodiment, the lower end portion of each rib 80 is located below the upper end portion of the support protrusion 75. That is, a part near the lower end of each rib 80 and a part near the upper end of the support protrusion 75 are located at the same height. In this way, the axial dimension of the entire motor 1 can be suppressed as compared with the case where the rib 80 and the support protrusion 75 are arranged at different positions in the axial direction.

Further, in the present embodiment, of the plurality of radiating ribs 82, the radiating rib 821 having the longest radial dimension and the radiating rib 822 having the shortest radial dimension are located on opposite sides of the annular rib 81. To do. By making the radial lengths of the radial ribs 82 arranged on a straight line different in this way, the resonance of the top plate portion 261 can be suppressed. Further, the motor 1 has a plurality of terminal portions 231 protruding inward in the radial direction from the bus bar holder 24. Then, as shown in FIG. 3, the radial rib 821 having the longest radial dimension is located between the two terminal portions 231 when viewed in the axial direction. In this way, the radial rib 821 and the terminal portion 231 having the longest radial dimension do not overlap in the axial direction. For this reason. The terminal portion 231 and the cover 26 can be arranged close to each other in the axial direction. As a result, the axial dimension of the entire motor 1 can be further suppressed.

Further, in the present embodiment, a cover protrusion 264 that projects downward is provided on the lower surface of the flange portion 263. As described above, the cover protrusion 264 not only serves to position the cover 26 with respect to the bus bar holder 24, but also plays a role of improving the strength of the flange portion 263. As a result, the strength of the cover 26 against flying stones can be further increased.

<3. Modification example>
Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. Hereinafter, various modifications will be described focusing on the differences from the above-described embodiment.

<3-1. First modification>
FIG. 8 is a vertical cross-sectional view of the cover 26A according to the first modification. In the example of FIG. 8, a plurality of grooves 83A are provided on the upper surface of the top plate portion 261A of the cover 26A. The plurality of grooves 83A are provided along the rib 80A. That is, the plurality of grooves 83A includes an annular groove provided along the annular rib and a plurality of radial grooves provided along the plurality of radial ribs. Even with such a structure, the strength of the top plate portion 261A can be improved as compared with the case where the rib 80A is not provided. Further, in the structure of this modified example, the thickness of the top plate portion 261A can be brought close to a constant value. Therefore, it is possible to suppress the occurrence of molding defects such as sink marks during the production of the cover 26A.

<3-2. Second modification>
FIG. 9 is a side view of the cover 26B according to the second modification. In the example of FIG. 9, the upper surface of the top plate portion 261B of the cover 26B is a curved surface 266B that bulges upward. Specifically, the height of the upper surface of the top plate portion 261B gradually increases from the upper end portion of the peripheral wall portion 262B toward the center of the top plate portion 261B. In this way, when an external force is applied to the upper surface of the top plate portion 261B, the top plate portion 261B is less likely to be dented downward. Therefore, the strength of the top plate portion 261B against stepping stones is further improved.

<3-3. Third variant>
FIG. 10 is a side view of the cover 26C according to the third modification. In the example of FIG. 10, the upper surface of the top plate portion 261C of the cover 26C has a plurality of curved surfaces 266C swelling upward. Further, the plurality of curved surfaces 266C have equal heights and are arranged in a direction perpendicular to the central axis. Even with such a structure, when an external force is applied to the upper surface of the top plate portion 261C, the top plate portion 261C is less likely to be dented downward. Therefore, the strength of the top plate portion 261C against stepping stones is further improved.

Further, in the structure of this modification, the upper surface of the top plate portion 261C is substantially flat as a whole. Therefore, when the cover 26C is laser welded to the bus bar holder, the top plate portion 261C can be easily pressed by the jig.

<3-4. Other variants>
In the above embodiment, the bus bar holder and the cover are fixed by laser welding. However, the bus bar holder and the cover may be welded by applying energy between the bus bar holder and the bar by a method other than the laser. For example, vibration welding or ultrasonic welding may be used instead of laser welding. Further, the method of fixing the cover to the bus bar holder may be another method such as adhesion.

Further, in the above embodiment, the stator is fixed to the inner peripheral surface of the metal housing. However, the housing may be manufactured by injection molding of resin. In that case, the stator may be embedded inside the housing. In this way, the weight of the housing can be reduced and the waterproofness of the stator can be further improved.

Further, the number of ribs provided on the cover, the thickness of the ribs, the shape of the ribs, and the like may be appropriately changed as long as the gist of the present invention is not deviated.

Further, the detailed shape of each member constituting the motor may be different from the shape shown in each figure of the present application. Further, the elements appearing in the above-described embodiments and modifications may be appropriately combined as long as there is no contradiction.

The present invention can be used for motors and transmission devices.

1 Motor 2 Stationary part 3 Rotating part 9 Central axis 21 Stator 22 Housing 23 Bus bar 24 Bus bar holder 25 Circuit board 26, 26A, 26B, 26C Cover 27 Lower bearing 28 Upper bearing 29 Oil seal 31 Shaft 32 Rotor 41 Stator core 42 Insulator 43 Coil 51 Bottom plate 52 Stator holding 55 Flange 56 Crimping piece 57 O-ring 58 Lower cylinder 60 Through hole 61 Rotor core 62 Magnet 71 Inner plate 72 Cylindrical 73 Outer plate 74 Connector 75 Support protrusion 76 Upper bearing Holding member 77 Holder protrusion 80, 80A Rib 81 Circular rib 82,821,822 Radiation rib 83A Groove 90 Recess 91 Central recess 92 Outer recess 100 Transmission device 231 Terminal part 261,261A Top plate part 261A, 261B, 261C Top plate part 262 , 262B Peripheral wall part 263 Flange part 264 Cover protrusion 265 Notch 266B, 266C Curved surface

Claims (16)

An annular stator centered on a vertically extending central axis,
A rotor that is rotatably supported around the central axis inside the stator in the radial direction.
A bottomed tubular housing that houses the stator and rotor inside,
A metal bus bar that is electrically connected to a wire drawn upward from the stator,
A busbar holder that is placed on top of the housing and holds the busbar,
With a resin cover
With
The cover is
A top plate covering the upper part of the bus bar holder and
A plurality of ribs protruding downward from the top plate,
Have,
The plurality of ribs
An annular rib and an annular rib in the bottom view,
A plurality of radial ribs extending radially outward from the annular rib,
Including the motor. The motor according to claim 1.
A motor in which the width of the rib becomes narrower toward the bottom. The motor according to claim 1 or 2.
The center of the annular rib is a motor located on the central axis. The motor according to claim 3.
Further provided with a shaft extending along the central axis
A motor in which the radius of the annular rib is larger than the radius of the shaft and smaller than the radius of the rotor. The motor according to claim 3 or 4.
A motor in which the plurality of radial ribs are provided at equal angular intervals in the circumferential direction. The motor according to any one of claims 1 to 5.
The lower surface of the cover is
The central recess surrounded by the annular rib and
A plurality of outer recesses located on the radial outer side of the annular rib and between the adjacent radial ribs,
Have,
A motor in which the area of the central recess is larger than the area of the smallest outer recess among the plurality of outer recesses and smaller than the area of the largest outer recess in the bottom view. The motor according to any one of claims 1 to 6.
A circuit board located above the bus bar and below the top plate is further provided.
The bus bar holder
A plate-shaped part that holds the bus bar and
A support protrusion that projects upward from the plate-shaped portion and supports the circuit board,
Have,
The lower end of the rib is a motor located below the upper end of the support protrusion. The motor according to any one of claims 1 to 7.
A motor in which the axial thickness from the upper surface of the top plate portion to the lower end portion of the rib is larger than the axial thickness of the top plate portion. The motor according to any one of claims 1 to 7.
A motor having a groove along the rib on the upper surface of the top plate portion. The motor according to any one of claims 1 to 9.
A motor in which, among the plurality of radiating ribs, the radiating rib having the longest radial dimension and the radiating rib having the shortest radial dimension are located on opposite sides of the annular rib. The motor according to any one of claims 1 to 10.
Further provided with a plurality of terminals protruding from the bus bar holder,
The radiant rib having the longest radial dimension among the plurality of radiant ribs is a motor located between the two terminal portions when viewed in the axial direction. The motor according to any one of claims 1 to 11.
A motor having a curved surface that bulges upward on the upper surface of the top plate portion. The motor according to claim 12.
The upper surface of the top plate portion has a plurality of the curved surfaces.
A motor in which the heights of the plurality of curved surfaces are equal. The motor according to any one of claims 1 to 13.
The cover is
A peripheral wall portion extending downward from the peripheral edge portion of the top plate portion,
A flange portion that extends radially outward from the lower end portion of the peripheral wall portion,
Have more
The lower surface of the flange portion is
A motor with a cover protrusion that projects downward. The motor according to claim 14.
The cover protrusion is a motor that comes into contact with the inner peripheral surface or the outer peripheral surface of the upper end portion of the bus bar holder. A transmission device comprising the motor according to any one of claims 1 to 15.

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