JP2018137990A - motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent metal powder from entering into a motor interior part even if the metal powder is generated by components, such as screws, metal machine screws, or rivets, which are used when a motor is attached to a device body, rubbing against an attachment portion of the motor.SOLUTION: A motor 1 has: a shaft 31; a rotor magnet 33; an armature 29; and a casing. The casing has an opening 228 which is a hole penetrating through an axial end surface in an axial direction. The motor further has a cover member 71 disposed at a position facing the opening in between the casing and the armature. An upper surface of the cover member contacts with at least part of the armature.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an inner rotor type motor.

  In the inner rotor type motor, in recent years, a small and high output motor has been demanded.

  In order to increase the output of the motor, it is necessary to increase the stacking thickness of the armature or increase the thickness of the winding.

  In Patent Document 1, the lid bodies 5 and 6 and the annular stator 1 are fastened to each other by a fixing screw 7 that penetrates the annular stator 1 in the axial direction.

In Patent Document 2, a metal core 9 having high thermal conductivity, a rivet 10 and a burring 11 are passed through a hole 8 to attach a stator core 13 and a base 16. At that time, an insulator 14 that is an insulator, that is, a convex portion 17 is provided between the metal part and the winding 5 so as not to contact each other.
Patent 3862844 JP 2001-136699 A

  In the conventional motor, parts such as screws, metal screws and rivets are used when the motor is attached to the apparatus body. However, when such components are rubbed into the motor mounting portion, metal powder is generated, and there is a risk that metal components may enter the motor.

  The present invention provides an inner rotor type motor having a structure that solves the above-mentioned problems.

  The motor according to the first aspect of the present invention includes a shaft, a rotor magnet, an armature, and a casing. The shaft is supported rotatably by a bearing member around a central axis extending vertically. The rotor magnet rotates with the shaft. The armature is located on the radially outer side of the rotor magnet. The casing holds the upper bearing and the lower bearing that fix the armature and rotatably support the shaft in the center in the radial direction. The armature has a stator core, an insulator, and a coil. The stator core includes an annular core back and a plurality of magnetic pole teeth protruding radially inward from the core back, and the insulator covers at least an upper surface and a lower surface of the magnetic pole teeth of the stator core. The coil is configured by winding a conductive wire around the magnetic pole teeth via an insulator. The casing has an opening which is a hole penetrating in the axial direction on the axial end face. A cover member is further disposed between the casing and the armature at a position facing the opening. The upper surface of the cover member is in contact with at least a part of the armature.

  According to the present invention, foreign matter can be prevented from entering the motor. As a result, the reliability of the motor can be improved.

FIG. 1 is an external perspective view of a motor. FIG. 2 is an external perspective view of the motor. FIG. 3 is a cross-sectional view of the motor. FIG. 4 is a plan view of the motor with the upper bracket removed. FIG. 5 is a perspective view of the upper insulator. FIG. 6 is a plan view of the upper insulator. FIG. 7 is a perspective view of the lower insulator. FIG. 8 is a cross-sectional view of a motor according to a modification. FIG. 9 is a cross-sectional view of a motor according to a modification. FIG. 10 is a cross-sectional view of a motor according to a modification. FIG. 11 is a cross-sectional view of a motor according to a modification. FIG. 12 is a plan view of a cover member according to a modified example.

  Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings. Below, let the direction along the central axis of a motor be an up-down direction. The shape and positional relationship of each part will be described with the circuit board side facing up with respect to the stator core. However, this defines the vertical direction for the convenience of explanation, and does not limit the posture when the motor according to the present invention is used.

<1. Overall configuration of motor>
The motor of this embodiment is mounted on household appliances, such as an air conditioner, an air cleaner, and a refrigerator, and is used as a drive source of a fan or a pump, for example. It is also used as a drive source for industrial equipment such as sorters. However, the motor of the present invention may be a motor used for other purposes. For example, the motor of the present invention may be mounted on an OA (Office Automation) device, a medical device, an automobile, or the like and generate various driving forces. Hereinafter, a device on which the motor 1 is mounted is referred to as a “drive device”.

  1 and 2 are external perspective views of the motor 1 according to this embodiment. FIG. 3 is a cross-sectional view of the motor 1. As shown in FIGS. 1, 2, and 3, the motor 1 includes a stationary portion 2 and a rotating portion 3. The stationary part 2 is fixed to a frame of a driving device (not shown). The rotating unit 3 is supported so as to be rotatable with respect to the stationary unit 2.

  The stationary portion 2 of the present embodiment includes an upper bracket 21, a lower bracket 22, a stator core 23, a coil 24, an upper insulator 25, a lower insulator 26, a circuit board 27, and a bearing portion 28.

  The upper bracket 21 holds the stator core 23 and the bearing portion 28 (upper bearing 281). The upper bracket 21 has a substantially cylindrical shape with a lid. The upper bracket 21 is a metal member. The upper bracket 21 is obtained by a so-called pressing method in which a steel sheet is punched and molded. In addition, the manufacturing method may be processed by other processing methods such as a die casting method instead of the press method. The upper bracket 21 may be made of resin instead of metal.

  The lower bracket 22 holds the stator core 23 and the bearing portion 28 (lower bearing 282). The lower bracket 22 has a substantially cylindrical shape with a bottom. The lower bracket 22 is a metal member.

  The lower bracket 22 is obtained by a so-called pressing method in which a steel sheet is punched and molded. In addition, the manufacturing method may be processed by other processing methods such as a die casting method instead of the press method. The lower bracket 22 may be made of resin instead of metal. Moreover, in this embodiment, the stator core 23 and the bearing part 28 (lower bearing 282) are hold | maintained with the lower bracket 22 which is a single member. For this reason, the stator core 23 and the shaft 31 described later can be positioned with high accuracy.

  The stator core 23 and the coil 24 are parts that function as an armature of the motor 1. The stator core 23 is made of a laminated steel plate in which electromagnetic steel plates such as silicon steel plates are laminated in the axial direction (direction along the central axis J1, hereinafter the same). The stator core 23 has an annular core back 231 and a plurality of magnetic pole teeth 232 protruding from the core back 231 toward the inside in the radial direction. The core back 231 is held by being sandwiched between the upper bracket 21 and the lower bracket 22. The outer peripheral surface of the core back 231 becomes the outer peripheral surface of the motor 1 except for the upper part in the axial direction and the lower part in the axial direction. The circumferential width of the portion around which the coil 24 of each magnetic pole tooth 232 of the stator core 23 is wound is not more than twice the radial width of the core back 231. In the present embodiment, the number of magnetic pole teeth 232 is six.

  Here, the outer peripheral surface of the stator core 23 is not covered with the lower bracket 22 and the upper bracket 21 except for the vicinity of the upper end and the vicinity of the lower end, and is exposed from the lower bracket 22 and the upper bracket 21. That is, compared with the case where the entire outer peripheral surface of the stator core 23 is covered with the lower bracket 22 and the upper bracket 21, in the present embodiment, the radial facing area between the outer peripheral surface of the stator core 23 and the lower bracket 22 and the upper bracket 21 is smaller. small. For this reason, even if the lower bracket 22 and the upper bracket 21 are magnetic bodies, magnetic flux leakage from the outer peripheral surface of the stator core 23 to the lower bracket 22 and the upper bracket 21 hardly occurs. Therefore, iron loss due to the lower bracket 22 and the upper bracket 21 can be reduced, and the energy efficiency of the motor 1 can be improved.

  Through holes 233 are formed at the boundaries between several core backs 231 and magnetic pole teeth 232 of the stator core 23. In the present embodiment, the number of through holes 233 is three. The through holes 233 are desirably arranged at equal intervals in the circumferential direction around the central axis. In the present embodiment, the through holes 233 are arranged with an interval of 120 degrees when viewed from the central axis. The through hole 233 is not limited to this, and may be a groove recessed inward in the radial direction.

  A longitudinal groove extending in the axial direction is formed on the outer peripheral surface of the stator core 23. The protrusion of the upper bracket 21 and the protrusion of the lower bracket 22 are inserted or fitted into the vertical groove. As a result, the upper bracket 21 and the lower bracket 22 are positioned in the radial direction and the circumferential direction.

  The coil 24 is configured by a conductive wire wound around the magnetic pole teeth 232. The coil 24 is wound around the magnetic pole teeth 232 via an insulator. In this embodiment, the conducting wire is connected by so-called star connection. Therefore, four ends of the U phase, the V phase, the W phase, and the common are drawn out from the coil 24. Each drawn end is soldered to the circuit board 27. When a drive current is applied to the coil 24 via the circuit board 27, a magnetic flux in the radial direction is generated in the magnetic pole teeth 232 that are the magnetic core. Then, circumferential torque is generated by the action of the magnetic flux between the magnetic pole teeth 232 and the rotor magnet 33 on the rotating unit 3 side. As a result, the rotating unit 3 rotates about the central axis J1 with respect to the stationary unit 2.

  The insulator includes an upper insulator 25 and a lower insulator 26. The upper insulator 25 and the lower insulator 26 are resin members that electrically insulate the stator core 23 and the coil 24 from each other. The upper insulator 25 is disposed on the upper side of the stator core 23. The lower insulator 26 is disposed below the stator core 23. In other words, the stator core 23 is sandwiched between the upper insulator 25 and the lower insulator 26. The upper insulator 25 covers the upper surface of the magnetic pole teeth 232. The lower insulator 26 covers the lower surface of the magnetic pole teeth 232. The upper insulator 25 and the lower insulator 26 cover the side surfaces of the magnetic pole teeth 232. The upper insulator 25 and the lower insulator 26 constitute an insulator. In the present embodiment, the coil 24 is wound around the magnetic pole teeth 232 from above the upper insulator 25 and the lower insulator 26, so that the insulator is fixed to the stator core 23.

  The upper insulator 25 and the lower insulator 26 have a portion that is interposed between the magnetic pole teeth 232 and the coil 24 and electrically insulates the magnetic pole teeth 232 and the coil 24. Further, the upper insulator 25 has an annular core back insulating portion 252 that is continuous in the circumferential direction outside the coil 24 in the radial direction. The core back insulating part 252 is disposed on the radially outer side of the coil 24. The core back insulating part 252 is a part that insulates from other members when the coil 24 collapses. An assembly of the stator core 23, the coil 24, the upper insulator 25, and the lower insulator 26 is defined as an armature 29. Details of the upper insulator 25 and the lower insulator 26 will be described later.

  FIG. 4 is a plan view of the motor 1 according to this embodiment with the upper bracket 21 removed. Referring to FIG. 4, circuit board 27 is a board having wiring for supplying a drive current to coil 24 from an external power source. The circuit board 27 has a substantially disk shape in plan view. The outer shape of the circuit board 27 substantially matches the outer shape of the upper insulator 25 described later. The circuit board 27 is fixed on a seating surface that is an upper surface of the upper insulator 25. Further, a magnetic sensor 271 for detecting the number of rotations of the rotating unit 3 is provided on the lower surface of the circuit board 27. For the magnetic sensor 271, for example, a Hall element is used.

  With reference to FIG. 3, the bearing portion 28 is a member that rotatably supports the shaft 31 of the rotating portion 3. The bearing portion 28 includes an upper bearing 281 and a lower bearing 282. The upper bearing 281 is held on the inner peripheral surface 2121 of the holding portion 212 of the upper bracket 21. The lower bearing 282 is held by the lower bracket 22. For the bearing portion 28, for example, a ball bearing that relatively rotates an outer ring and an inner ring via a sphere is used. However, another type of bearing such as a slide bearing or a fluid bearing may be used for the bearing portion 28.

  The rotating unit 3 of this embodiment includes a shaft 31, a rotor holder 32, and a rotor magnet 33. The shaft 31 is a substantially cylindrical member extending in the vertical direction along the central axis J1. The shaft 31 rotates about the central axis J1 while being supported by the bearing portion 28 described above. The lower end portion of the shaft 31 protrudes downward from the lower bracket 22. Further, the upper end portion of the shaft 31 protrudes above the circuit board 27. A lower end portion or an upper end portion of the shaft 31 is connected to a drive unit of the drive device via a power transmission mechanism such as a gear. However, the drive unit of the drive device may be directly driven by the shaft 31.

  The rotor holder 32 is a member that rotates together with the shaft 31 on the radially inner side of the stator core 23 and the coil 24. The rotor holder 32 of this embodiment is configured by arranging a bottomed cylindrical upper rotor holder member 323 and a lower rotor holder member 324 back to back. That is, the bottom surface of the upper rotor holder member 323 and the bottom surface of the lower rotor holder member 324 are disposed to face each other with a minute gap. The upper rotor holder member 323 and the lower rotor holder member 324 are each obtained by a so-called pressing method in which a steel sheet is punched and molded.

  In the present embodiment, the rotor holder 32 is arranged with the upper rotor holder member 323 and the lower rotor holder member 324 back to back, but the present invention is not limited to this. The rotor holder 32 may be composed of a single member. Moreover, you may obtain by cutting free-cutting steel. Moreover, you may obtain the rotor holder 32 by laminating | stacking a magnetic steel plate. Further, the rotor holder 32 may be obtained by sintering. Alternatively, the rotor holder 32 may be obtained by combining a member obtained by laminating magnetic steel plates and a member obtained by press working with a substantially cylindrical shape with a lid. Further, the rotor holder 32 may be obtained by resin molding. In the present embodiment, the rotor is a so-called SPM type (Surface-permanent magnet), but is not limited to this. The rotor may be a so-called IPM type (Interior permanent-magnet, embedded magnet type). In the case of an IPM type rotor, the rotor holder 32 is preferably obtained by laminating magnetic steel plates.

  The rotor magnet 33 has a cylindrical shape and is fixed to the outer peripheral surface of the rotor holder 32. The radially outer surface of the rotor magnet 33 is a magnetic pole surface that faces the stator core 23 and the coil 24 in the radial direction. The rotor magnet 33 is magnetized so that the N-pole magnetic pole surface and the S-pole magnetic pole surface are alternately arranged in the circumferential direction. In addition, about the rotor magnet 33, it may replace with a cylindrical magnet and may arrange | position a several magnet so that a north-pole and a south pole may be located in a line by the circumferential direction. Further, as described above, an IPM type rotor may be used, and the rotor magnet 33 may be embedded in the rotor holder 32.

<2. About circuit boards>
FIG. 5 is an external perspective view of the upper insulator 25 according to the present embodiment. Referring to FIGS. 4 and 5, circuit board 27 has a substantially disk shape in plan view. The outer peripheral surface of the circuit board 27 is provided with a notch that is recessed radially inward from the outer periphery. This notch is a positioning portion 272. A positioning convex portion 254 of the upper insulator 25 described later is inserted into the positioning portion 272. Thereby, when the circuit board 27 tries to move relative to the upper insulator 25, the convex portion 254 contacts the positioning portion 272, and the movement is restricted. As a result, it is possible to accurately position the upper insulator 25 and the circuit board 27 in the circumferential direction and the radial direction.

  A connector 273 is provided on the upper surface of the circuit board 27. The motor 1 obtains a drive current via the connector 273.

  In addition, a cutout that is recessed radially outward from the outer periphery is provided on the outer peripheral surface of the circuit board 27. This notch is a buttock insertion portion 274. The collar insertion part 274 constitutes a part of the transmission part. A land is disposed in a region adjacent to the flange insertion portion 274 on the upper surface of the circuit board 27. A collar part 255 of the upper insulator 25 described later is inserted into the collar part insertion part 274. The buttock insertion portion 274 is located adjacent to the buttock insertion width narrow portion 2741 having a shorter notch radial width, and the radial direction than the buttock insertion width narrow portion 2741. And a wide flange insertion portion 2742 having a large width. More specifically, the collar part 255 is inserted into the collar part insertion width narrow part 2741.

  The outer peripheral surface of the circuit board 27 is provided with a notch that is recessed radially inward from the outer periphery. This notch is a winding lead portion 277. The winding lead part 277 constitutes a part of the transmission part. A land is disposed in a region adjacent to the winding lead portion 277 on the upper surface of the circuit board.

  A central opening 276 that opens in the axial direction is located in the center of the circuit board 27. A shaft 31 is located inside the central opening in the radial direction.

  It is necessary to dispose the wiring pattern at a certain distance from the edge of the circuit board 27. Therefore, the wiring area of the circuit board 27 can be increased as the number of holes and notches provided in the circuit board 27 is smaller. In the present embodiment, a portion for inserting a convex portion such as the collar insertion portion 274 (transmission portion) is enlarged to form a cutout for conducting wire. Thereby, the wiring area of the circuit board 27 can be increased.

  Especially when mounting large electronic components such as control ICs, AC-DC converters, encoders, connectors, etc. on the circuit board, or when increasing the width of the wiring pattern in order to pass a large current through the board, the area of the circuit board itself is reduced. This technique is useful when it is necessary to do so.

<3. About upper bracket and upper insulator ＞
First, the upper bracket 21 will be described in detail. The upper bracket 21 includes a lid portion 211, a holding portion 212, an upper protruding portion 213, a through hole 214, and an opening 215. The lid portion 211 has a flat plate shape and is positioned on the upper side in the axial direction of the circuit board 27. The holding part 212 is a concave part that is located on the inner side in the radial direction of the lid part 211 and opens toward the upper side in the axial direction. The holding part 212 has a cylindrical inner peripheral surface 2121 and an annular top surface 2122. The inner peripheral surface 2121 is in contact with the outer peripheral surface of the outer ring of the upper bearing 281. The top surface 2122 is in contact with the upper end surface of the outer ring of the upper bearing 281. Thereby, the holding part 212 holds the upper bearing 281. Further, the outer peripheral surface of the upper bearing 281 is smaller than the diameter of the central opening 276 of the circuit board 27. Thereby, interference of the upper bearing 281 with respect to the circuit board 27 can be prevented, and the motor 1 can be reduced in thickness.

  The upper protruding portion 213 protrudes from the outer side in the radial direction of the lid portion 211 toward the lower side in the axial direction. The protrusion 213 is substantially annular. Further, the upper protruding portion 213 has a substantially cylindrical shape. The inner peripheral surface of the upper protrusion 213 is in contact with the upper outer peripheral surface of the stator core 23. Thereby, the coaxial precision of center axis J1 and upper bearing 281 can be improved. Further, the rigidity of the upper bracket 21 can be improved. In the present embodiment, the stator core 23 is fixed to the upper bracket 21 by being press-fitted into the upper protruding portion 213. However, it is not limited to press-fitting and may be fixed by insertion bonding. When the upper bracket 21 and the stator core 23 are fixed by insertion bonding, the inner peripheral surface of the protruding portion 213 may be in contact with the outer peripheral surface of the circuit board 27 or the outer peripheral surface of the upper insulator 25. The rigidity of the upper bracket 21 can be improved by contacting the inner peripheral surface of the protruding portion 213 with the circuit board 27 and the upper insulator 25.

  A plurality of through holes 214 are arranged in the circumferential direction on the radially outer portion on the lid portion 211. In the present embodiment, the number of through holes 214 is six.

  Further, when an electronic component having a large calorific value is mounted on the circuit board 27, the electronic component is preferably disposed so as to face the electronic component. Thereby, the distance of an electronic component and the upper bracket 21 can be made close. As a result, heat generated from the electronic component can be radiated from the upper bracket 21. Further, a heat conducting material such as silicon may be interposed between the electronic component and the lid portion 211. This further promotes heat dissipation from the electronic component. An example of an electronic component that generates a large amount of heat is a field effect transistor (FET).

  The opening 215 is a through hole arranged in the lid portion 211. The connector 273 mounted on the circuit board 27 is exposed from the opening 215. Electric power is supplied to the motor 1 by being connected to the connector 273 through the opening 215.

  The shape of the upper insulator 25 will be described in detail with reference to FIG. The upper insulator 25 has a magnetic pole tooth insulating part 251 and a core back insulating part 252. The magnetic pole tooth insulating portion 251 covers the upper surface and the side surface of each magnetic pole tooth 232. The core back insulating part 252 is annular and connects the magnetic pole tooth insulating parts 251. A plate portion 2511 that protrudes upward in the axial direction is provided at the radially inner end of each magnetic pole tooth insulating portion 251. The core back insulating portion 252 extends axially upward on the radially outer side of the coil 24. The upper end surface of the core back insulating portion 252 is positioned on the upper side in the axial direction than the coil 24. Thereby, interference with the coil 24 and other members, such as the circuit board 27 and the upper bracket 21, can be prevented.

  The core back insulating part 252 has an annular wall part 253, a positioning convex part 254, and a flange part 255. The annular wall portion 253 is a substantially annular wall that protrudes in the axial direction from the radially outer end of the core back insulating portion 252. The upper surface of the annular wall portion 253 is a seat surface 2531, which is a plane substantially perpendicular to the central axis. The seating surface 2531 is in contact with the lower surface of the circuit board 27. More specifically, the seating surface 2531 is in contact with the lower surface near the outer edge of the circuit board 27. The outer end of the annular wall portion 253 is located radially inward from the outer end of the stator core 23. Therefore, the portion of the stator core 23 located on the radially outer side of the annular wall portion 253 is the upper core back exposed portion 41 exposed toward the upper side in the axial direction.

  The positioning convex portion 254 is located at substantially the same position in the radial direction as the annular wall portion 253, and protrudes toward the upper side in the axial direction from the seat surface 2531. Further, the positioning convex portion 254 is positioned on the lower side in the axial direction than the upper surface of the circuit board 27. Therefore, the positioning convex part 254 is accommodated in the positioning part 272 of the circuit board 27. As a result, the positioning convex portion 254 does not contact the upper bracket 21 even when the lower surface of the protruding portion 213 of the upper bracket 21 contacts the upper surface of the circuit board 27 as will be described later. Therefore, the circuit board 27 is firmly fixed.

  Moreover, in this embodiment, the positioning convex part 254 is provided in one place at intervals in the circumferential direction. In the present embodiment, the positioning convex portions 254 are provided at three places, but the present invention is not limited to this, and may be two or more places.

  The shape of the positioning convex portion 254 in plan view is substantially the same as that of the positioning portion 272, that is, the positioning convex portion 254 has a shape along the contour of the positioning portion 272. Thereby, the circuit board 27 can be accurately positioned with respect to the upper insulator 25.

  More preferably, the circumferential end surfaces of the positioning convex portion 254 are in contact with the circumferential end surface of the positioning portion 272. Further, the radial end surface of the positioning convex portion 254 is in contact with the radial end surface of the positioning portion 272. Thereby, the circuit board 27 can be accurately positioned with respect to the upper insulator 25. However, if a part of the end surface of the positioning convex portion 254 is in contact with the end surface of the positioning portion 272, the positioning can be accurately performed. If the circuit board 27 can be accurately positioned with respect to the upper insulator 25, the conductor can be soldered without being sandwiched between the upper insulator 25 and the circuit board 27 in the step of soldering the conductor to be described later. it can.

  A first window portion 2541 that is notched toward the lower side in the axial direction is located adjacent to the circumferential direction of the positioning convex portion 254. The axial position of the lower end of the first window portion 2541 is positioned below the upper end of the plate portion 2511 of the magnetic pole tooth insulating portion 251.

  The flange portion 255 is a portion that is located at a position overlapping the annular wall portion 253 in the radial direction and protrudes from the core back insulating portion 252 in the axial direction. The flange portion 255 is located at a position different from the magnetic pole tooth insulating portion 251 in the circumferential direction. The upper end in the axial direction of the flange portion 255 is located above the upper surface of the circuit board 27 and protrudes above the seating surface 2531 and the positioning convex portion 254 in the axial direction. The collar portion 255 has a collar-shaped portion 2551 on the upper side. The bowl-shaped part 2551 protrudes inward in the radial direction. The lower surface of the bowl-shaped portion 2551 is in contact with the upper surface of the circuit board 27 or opposed via a gap.

  A second window portion 2552 in which the flange portion 255 and the annular wall portion 253 are cut downward in the axial direction is located at a position adjacent to the flange portion 255 in the circumferential direction. The axial position of the lower end of the second window portion 2552 is located below the upper end of the plate portion 2511 of the magnetic pole tooth insulating portion 251.

  In addition, the positioning convex part 254 and the collar part 255 are convex parts.

  In addition, a third window portion 2531 that is cut downward in the axial direction is positioned on the annular wall portion 253 of the upper insulator 25. The axial position of the lower end of the third window portion 2531 is located below the upper end of the plate portion 2511 of the magnetic pole tooth insulating portion 251.

  In the present embodiment, the windows 2531 and 2552 are arranged at a total of five places, four places every 60 degrees and three places every 120 degrees (two of which overlap with those arranged every 60 degrees). ing. Thereby, it is possible to draw out the conductive wire in either case of connecting by star connection or connecting by delta connection. Therefore, even when the connection method is changed, the common upper insulator 25 can be used. However, if only the star connection is used, the windows 2531 and 2552 may be arranged at four locations in the circumferential direction.

<4. Lower bracket and lower insulator>
First, the lower bracket 22 will be described in detail. The lower bracket 22 includes a lower lid portion 221, a lower holding portion 222, and a lower protruding portion 223. The lower bracket 22 has a covered cylindrical shape. The lower lid portion 221 has a substantially annular flat plate shape. The lower holding part 222 is a recessed part that is located on the radially inner side of the lower lid part 221 and opens toward the lower side in the axial direction. The lower holding part 222 has a cylindrical inner peripheral surface 2221 and an annular top surface 2222. The inner peripheral surface 2221 is in contact with the outer peripheral surface of the outer ring of the lower bearing 282. The top surface 2222 contacts the lower end surface of the outer ring of the lower bearing 281 via a spring. As a result, the lower holding portion 222 holds the lower bearing 282.

  The lower protruding portion 223 protrudes from the radially outer side of the lower lid portion 221 toward the upper side in the axial direction. The lower protrusion 223 is substantially annular. Moreover, the lower protrusion part 223 is substantially cylindrical shape. The upper end of the lower protrusion 223 is in contact with the outer peripheral surface of the stator core 23. Thereby, the coaxial precision of the central axis J1 and the lower bearing 282 can be improved. Further, the lower bracket 22 and the stator core 23 can be firmly fixed. In the present embodiment, the stator core 23 is fixed to the lower bracket 22 by being press-fitted into the lower protrusion 223. However, it is not limited to press-fitting and may be fixed by insertion bonding. Moreover, the lower protrusion part 223 has the positioning step part 2231 in which an internal diameter becomes small. The upper surface of the positioning step 2231 is in direct contact with the core back 231 of the stator core 23. Thereby, a reduction in accuracy due to the axial positioning of the lower bracket 22 with respect to the stator core 23 is suppressed.

  The lower lid part 221 is provided with an opening 228. The openings 228 are a plurality of holes that penetrate the lower lid portion 221 in the axial direction. A screw groove is formed on the inner peripheral surface of the opening 228. When the motor is attached to the apparatus main body, it is fixed by screwing the screw into the opening 228.

  Here, an annular cover member 71 is disposed between the opening 228 and the armature 29. In the present embodiment, the cover member 71 is formed of an elastic body such as rubber, and the outer peripheral surface thereof is press-fitted into the inner peripheral surface of the lower protrusion 223 and fixed. However, the cover member 71 should just be arrange | positioned in the position facing the opening part 228 at least. Since the cover member 71 is interposed between the lower lid portion 221 and the armature 29, entry of foreign matter into the motor can be prevented. In particular, when the motor is attached to the apparatus main body, it is possible to prevent the metal powder from entering due to the screw and the opening 228 being rubbed. Therefore, the reliability of the motor can be improved. In the present embodiment, the upper surface of the cover member 71 is in contact with the coil 24 of the armature 29. The cover member 71 has elasticity. Therefore, the vibration and noise generated from the armature 29 can be reduced when the cover member 71 is in contact with the coil 24.

Further, in the present embodiment, the cover member 71 includes a collar portion 711 extending axially downward on the radially inner side of the opening 228 and a thick portion 712 having a thick axial thickness on the radially outer side of the opening 228. And a hem portion 713 that is located on the radially outer side of the thick portion 712 and that is thinner in the axial direction than the thick portion 712. The collar portion 711 contacts the lower lid portion 221 of the lower bracket 22. Thereby, it is possible to prevent dust from entering the lower bearing 282 and the rotor holder 32 side. A part of the inner peripheral surface of the collar portion 711 has an inclined portion whose axial height decreases as it goes radially inward. As a result, contact between the cover member 71 and the rotating portion 3 is avoided. Further, the cover member 71 is inserted into the inner peripheral surface of the lower protrusion 223 at the skirt 713. That is, the cover member 71 is inserted not in the thick wall portion 712 but in the thin skirt portion 713. Thereby, the insertion of the cover member 71 can be performed smoothly. Moreover, the thick part 712 is provided inside the skirt part 713, and the deformation | transformation of the cover member 71 whole can be suppressed. Therefore, it is possible to effectively prevent dust from entering the motor. The cover member 71 may be formed of plastic or other material instead of rubber. Further, the cover member 71 is inserted, but press fitting may be used. Further, the cover member 71 may be disposed not on the lower bracket 22 side but on the upper bracket 21 side, and may be disposed on both the upper bracket 21 side and the lower bracket 22 side.
As described above, in the conventional inner rotor type motor, when the upper bracket 21 and the lower bracket 22 are obtained by the pressing method, the opening 228 needs to be a through hole. As a result, there is a concern that dust may enter the motor. However, by using the above-described cover member 71, entry of foreign matter such as dust can be prevented.

  FIG. 6 is a plan view of the lower insulator 26. FIG. 7 is a perspective view of the lower insulator 26. The shape of the lower insulator 26 will be described in detail with reference to FIGS. 6 and 7. The lower insulator 26 includes a lower magnetic pole tooth insulating part 261 and a lower core back insulating part 262. The lower magnetic pole tooth insulating portion 261 covers the lower surface and the side surface of each magnetic pole tooth 232. The lower core back insulating part 262 is annular and connects the lower magnetic pole tooth insulating parts 261. The lower magnetic pole tooth insulating portion 261 has a plate portion 2611 that protrudes in the axial direction at the radially inner end thereof. The plate portion 2611 is a plate-like wall extending in the circumferential direction. The plate portion 2611 faces the inner end of the coil 24 in the radial direction. The lower core back insulating portion 262 includes a core back insulating protruding portion 2621 that protrudes in a direction away from the surface covering the core back 231 in the axial direction. The lower core back insulating protrusion 2621 is provided to be a wall in the circumferential direction.

  The lower core back insulating protrusion 2621 includes a notch 2622, a coil guide wall 2623, a crossover guide wall 2624, a continuous wall 2625, and a crossover holder 2626. The notch 2622 indicates a portion where the lower core back insulating protrusion 2621 is notched partially in the circumferential direction and becomes a wall. In the present embodiment, the portions where the lower core back insulating protrusion 2621 continuously forms a wall are a coil guide wall 2623, a crossover guide wall 2624, and a continuous wall 2625. The notch portion 2622 is provided in a portion of the lower core back insulating protrusion 2621 that faces the lower magnetic pole tooth insulating portion in the radial direction. Coil guide walls 2623 are disposed at both ends in the circumferential direction of the notch 2622. The circumferential width of the notch 2622 is narrower than the circumferential width of the magnetic pole teeth 232 around which the conducting wire is wound. In other words, the lower core back insulating protrusion 2621 is continuously formed at a place excluding the notch 2622. Thereby, the rigidity of the lower insulator 26 can be improved.

The coil guide wall 2623 is located on the radially outer side of the magnetic pole tooth insulating portion 261. The coil guide wall 2623 is located radially inward from the crossover guide wall 2624 described later. The inner surface in the radial direction of the coil guide wall 2623 is opposed to the outer side in the radial direction of the coil 24 configured by winding a conductive wire around the magnetic pole teeth 232. Preferably, the radially inner surface of the coil guide wall 2623 is in contact with the radially outer side of the coil 24. The coil 24 has multiple conductors wound around the magnetic pole teeth 232. That is, it is necessary to prevent the winding from being collapsed by an insulator or other member so that the multiple conducting wires are not collapsed. By providing the coil guide wall 2623, the coil 24 is prevented from collapsing radially outward.
The crossover guide wall 2624 is connected to the coil guide wall 2623 and provided integrally therewith. That is, the coil guide wall 2623 and the crossover guide wall 2624 are provided via the continuous wall 2625. By connecting the coil guide wall 2623 and the crossover guide wall 2624 by the continuous wall 2625, the rigidity of the coil guide wall 2623 is increased. As a result, even if the conductor is wound and tension is applied to the core back insulating protrusion 2621, the core back insulating protrusion 2621 can be prevented from falling. The coil guide wall 2623 is located radially inward from the crossover guide wall 2624. The radial thickness of the crossover guide wall 2624 is thinner than the radial thickness of the coil guide wall 2623.

  The crossover guide wall 2624 is a wall-shaped part that guides the crossover line led out from the coil 2623. The crossover guide wall 2624 protrudes in a direction away from the surface covering the core back in the axial direction. A crossover holding portion 2626 is provided inward in the radial direction of the crossover guide wall 2624. The connecting wire holding part 2626 supports the connecting wire on the outer surface in the radial direction. The inner wall of the crossover guide wall 2624 and the crossover holding part 2626 are opposed to each other in the radial direction. A conducting wire that is a connecting wire is arranged between the connecting wire guide wall 2624 and the connecting wire holding portion 2626 and guided. In the crossover holding part 2626, a slope is provided on the outer surface at the upper end in the axial direction. This is because when the conducting wire, which is a connecting wire, is inserted between the connecting wire guide wall 2624 and the connecting wire holding portion 2626, the conducting wire is guided by the inclined surface, and workability can be improved. In the present embodiment, the crossover lines are concentrated on the lower bracket 22 side. Therefore, no crossover is formed on the upper bracket 21 side where the circuit board 27 is disposed. As a result, there is no need to consider crossovers in the arrangement of the wiring pattern on the circuit board 27, and the degree of freedom in circuit design is improved.

  The crossover guide wall 2624 has an inclined portion 2628 whose height in the axial direction gradually decreases from both ends in the circumferential direction toward the center in the circumferential direction. The central portion 2629 located at the center in the circumferential direction of the crossover guide wall 2624 has a lower axial position than the inclined portion 2628. In other words, the upper end of the portion (central portion 2629) of the crossover guide wall 2624 facing the crossover holding portion 2626 in the radial direction is lower in the axial direction than the upper end of the crossover holding portion 2626. By comprising in this way, when winding a winding, the nozzle of a winding machine can be inserted to the back. As a result, the crossover wire can be reliably hooked on the crossover wire holding portion 2626. Moreover, since the axial height of the central portion 2629 of the crossover guide wall 2624 is kept low, the crosswise height of the crossover holding portion 2626 can be relatively reduced. Therefore, the moment load applied when the crossover wire is hooked on the winding holding portion 2626 can be kept small. As a result, the crossover holding part 2626 can be prevented from falling in the radial direction.

  The ratio of the width of the gap in the radial direction between the crossover guide wall 2624 and the crossover holder 2626 to the height of the crossover holder 2626 is preferably 1 to 3 or less. This is because in the present embodiment, the motor is a three-phase motor, and the three jumper wires overlap. More preferably, it is 1 to 4 or less. This is because there is a possibility that a jumper may be further provided for adjusting the inductance, adjusting the drawing position of the winding, and the like. By setting in this way, the crossover can be reliably held.

  Further, the height in the axial direction of the central portion 2629 of the crossover guide wall 2624 is lower than that of the coil guide wall 2623, the continuous wall 2625, and the crossover holding portion 2626. By comprising in this way, the axial thickness of the winding guide wall 2624 can be made thin. As a result, the lower insulator 26 can be made thinner, and the motor can be made thinner.

  Moreover, the height of the crossover holding part 2626 in the axial direction is lower than that of the coil guide wall 2623 and the continuous wall 2625. Further, the height of the crossover holding portion 2626 in the axial direction is lower than the height of the plate portion 2611 of the lower insulator 26 in the axial direction.

<5. Assembly of armature and circuit board>
Next, an assembly process of the armature 29, the circuit board 27, the upper bracket 21, and the lower bracket 22 will be described. The assembly of the stator core 23, the coil 24, the upper insulator 25, and the lower insulator 26 is defined as an armature 29.

  First, the ends of U, V, W, and common of the coil 24 are pulled out radially outward from the windows 2541 and 2552 of the upper insulator 25. Thereby, even if the circuit board 27 is placed on the armature 29, the conductive wire is not sandwiched between the upper insulator 25 and the circuit board 27.

  Next, the circuit board 27 is placed on the seat surface 2531 of the upper insulator 25 of the armature 29. At this time, the positioning convex portion 254 is inserted into the positioning portion 272 of the circuit board 27. Thereby, the circuit board 27 can be accurately positioned with respect to the armature 29. Thereby, the magnetic sensor 271 mounted on the circuit board 27 can be accurately arranged. Further, the flange portion 255 is inserted into the flange portion insertion portion 274 of the circuit board 27. The flange portion 255 is elastically deformed, and the portion 2551 comes into contact with the upper surface of the circuit board 27 or faces in the axial direction through a gap. Thereby, the movement of the circuit board 27 in the axial direction with respect to the armature 29 can be restricted, and the circuit board 27 can be temporarily fixed.

  At this time, the circumferential positions of the windows 2541 and 2552 and the flange insertion portion 274 coincide with each other. Preferably, the positions in the circumferential direction of the windows 2541 and 2552 and the flange insertion wide portion 2742 coincide with each other. Thereby, the workability | operativity of the soldering described below improves.

  Next, each drawn end is soldered to a land located on the upper surface of the circuit board 27. At this time, a part of the lands is arranged adjacent to the buttock insertion portion 274. Therefore, it can be easily soldered.

<3. Modification>
As mentioned above, although exemplary embodiment of this invention was described, this invention is not limited to said embodiment.

<3-1. Modification 1>
For example, FIG. 8 is a diagram showing another embodiment of the present application. In the following description, the points different from the exemplary embodiment of the present invention will be mainly described. Referring to FIG. 8, lower bracket 22 </ b> A covers the outer peripheral surface of armature 29. More specifically, the axial length of the lower bracket 22 </ b> A in the present embodiment is longer than the axial length of the stator core 23. The axial length of the lower bracket 22A is longer than the combined length of the upper insulator 25 and the lower insulator 26 in the axial direction. More specifically, the axial length of the lower protruding portion 223A of the lower bracket 22A is longer than the total length of the upper insulator 25 and the lower insulator 26 in the axial direction. On the upper side of the lower protruding portion 223A of the lower bracket 22A, a caulking portion 224A for fixing an upper bracket 21A described later is formed. The upper bracket 21A has a substantially disk shape and does not have the upper protruding portion 213A. The upper bracket 21A is fixed to the lower bracket by plastic deformation of the caulking portion 224A. In this way, a casing may be formed.

  Thus, by covering the entire outer side of the armature 29 with the casing, vibration and noise generated inside the motor can be suppressed. Further, dust can be prevented from entering the motor.

<3-2. Modification 2>
For example, FIG. 9 is a diagram showing another embodiment of the present application. Referring to FIG. 9, the lower holding portion 222B of the lower bracket 22B extends greatly upward in the axial direction. The lower holding portion 222B holds the upper bearing 281B in addition to the lower bearing 282B. Further, in this embodiment, there is no upper bracket, and the circuit board 27 is exposed. However, it is possible to arrange a member that covers the substrate in place of the upper bracket.

  As still another embodiment of the present application, as shown in FIG. 10, the lower bracket 22C may be provided with two members, an inner lower bracket 22C1 and an outer lower bracket 22C2.

<3-3. Modification 3>
For example, FIG. 11 is a diagram showing another embodiment of the present application. Referring to FIG. 11, in the present embodiment, upper bracket 21D and lower bracket 22D are fixed to armature 29D by fixing member 61D. First, the outer peripheral surface of the circuit board 27D is provided with a notch that is recessed radially outward from the outer periphery. This notch is a fixing member insertion portion 275D. The fixing member insertion portion 275D has a surface corresponding to the projected shape of the screw portion of the fixing member (screw 61D) in plan view. In the present embodiment, the upper bracket 21D and the lower bracket 22D are molded by a die casting method. Therefore, in this embodiment, the opening 228 does not need to be a through hole. Therefore, even if the cover member 71 is omitted, there is little risk of dust entering the motor.

  The upper bracket 21D has a through hole 214D. A plurality of through-holes 214D are arranged in the circumferential direction on the radially outer portion on the lid 211D. In the present embodiment, the number of through holes 214D is three. A screw 61D is inserted into each through hole 214D. A seat surface 2141D is disposed around the through hole 214D. The seat surface 2141D is located on the lower side in the axial direction than the lid portion 211D. The head of the screw 61D is in contact with the seating surface 2141D. In other words, the screw 61D has a lower surface that contacts the upper surface of the upper bracket 21D. Thereby, even when the screw 61D is inserted, the screw 61D can be prevented from protruding upward in the axial direction from the lid portion 211D. Thereby, the motor 1D can be thinned. The diameter of the screw portion of the screw 61D is the same as or slightly smaller than the diameter of the through hole 214D. Thereby, after the screw 61D is inserted, the movement of the upper bracket 21D in the circumferential direction with respect to the armature 29D is suppressed. Accordingly, the upper bracket 21D and the armature 29D can be firmly fixed. The fixing member 61D may be a rivet. Further, a ground pattern may be formed on the edge of the fixed portion insertion portion 275D of the circuit board 27D. Thereby, the ground can be taken between the ground pattern of the circuit board 27D and the upper bracket 21D by the screw 61D.

  The upper insulator 25D is provided with a fixing member insertion recess 256D. The fixing member insertion recess 256D is a recess that is recessed inward in the radial direction from the outer edge of the core back insulating portion 252D. A screw 61D is inserted into the fixing member insertion recess 256D. The fixing member insertion recess 256D may be a hole that opens upward in the axial direction, instead of a recess recessed inward in the radial direction.

  The lower bracket 22D has a lower fixing member accommodating portion 224D. A plurality of lower fixing member accommodating portions 224D are arranged in the circumferential direction on the radially outer portion on the lower lid portion 221D. In the present embodiment, the number of lower fixing member accommodating portions 224D is three. The arrangement of the lower fixing member accommodating portion 224D coincides with the circumferential position of the through hole 214D of the upper bracket. A screw 61D is inserted into each lower fixing member accommodating portion 224D. In the present embodiment, the lower fixing member accommodating portion 224D is a bag-like hole and does not penetrate, but may be a through-hole.

  The shape of the lower insulator 26 in the present embodiment is the same as that shown in FIGS. With reference to FIG. 6 and FIG. 7, the notch 2622 of the lower core back insulating protrusion 2621 in the present embodiment is located at a portion of the lower core back insulating protrusion 2621 that faces the lower magnetic pole tooth insulating portion in the radial direction. Provided. The fixing member disposing portion 44D and the screw 61D of the stator core 23 are located outward of the notch portion 2622 in the radial direction. That is, the notch 2622 faces the screw 61D in the radial direction. In other words, a portion of the lower core back insulating protrusion 2621 that faces the screw 61D in the radial direction has a notch 2622 that is notched.

  The coil guide wall 2623 is located on the radially outer side of the magnetic pole tooth insulating portion 261. The inner surface in the radial direction of the coil guide wall 2623 is in contact with the outer side in the radial direction of the coil 24D configured by winding a conductive wire around the magnetic pole teeth 232D. The coil 24D has multiple conductors wound around the magnetic pole teeth 232D. That is, it is necessary to prevent the winding from being collapsed by an insulator or other member so that the multiple conducting wires are not collapsed. In particular, in the present embodiment, the fixing member arranging portion 44D and the screw 61D are located on the outer side in the radial direction of the coil 24D. In the unlikely event that the coil 24D collapses, when assembling the motor, the fixing member arranging portion 44D and the coil 24D may overlap in plan view. That is, in that case, the screw 61D cannot be inserted into the fixing member arrangement portion 44D. In addition, after the screw 61D is inserted into the fixing member placement portion 44D, if the coil 24D collapses due to a change in fixing, there is a possibility that the screw 61D contacts the screw 61D. When the screw 61D is made of a conductor, the dielectric strength cannot be maintained. By providing the coil guide wall 2623, the coil 24 is prevented from collapsing radially outward.

  A screw 61D is inserted into the fixing member arranging portion 44D, and the upper bracket 21D, the armature 29D, and the lower bracket 22D are fixed. The radially inner end of the fixing member arranging portion 44D is located radially inward from the outer surface of the coil guide wall 2623D. The radially inner end of the fixing member placement portion 44D is located radially outside the inner surface of the coil guide wall 2623. The core back insulating portion 262D has a recess 2627. The recess 2627 is located on the periphery of the fixing member arrangement portion 44D and is recessed radially inward. In other words, the recessed portion 2627 is recessed inward in the radial direction along the periphery of the fixing member arranging portion 44D. Since the lower insulator 26D and the stator core 23D are mass-produced products, they are molded with a certain dimensional tolerance. Therefore, when combining both, by providing the concave portion 2627, it is possible to prevent the lower core back insulating portion 262D and the fixing member disposing portion 44D from overlapping each other in plan view. That is, when the screw 61D is inserted into the fixing member arranging portion 44D, the screw 61D can be prevented from contacting the lower insulator 26D. The radially inner end of the recess 2627 is located radially outside the inner surface of the coil guide wall 2623. As a result, the coil 24D is accommodated radially inward from the inner surface of the coil guide wall 2623, so that the coil 24D and the stator core 23D can be reliably insulated.

<3-4. Modification of cover member>
FIG. 12 is a view showing a modification of the cover member that can be applied to the embodiment. Referring to FIG. 12, cover member 71E has an annular portion 714E, an outer peripheral portion 715E, and accommodating portions 716E and 717E. The cover member 71E in this embodiment is made of resin. However, the cover member 71E may be made of rubber. The annular portion 714E has a donut-like disk shape, and connects the accommodating portions 716E and 717E. The outer peripheral portion 715E is located on the radially outer side of the annular portion 714E. The outer peripheral portion 715E has a cylindrical shape. The cover member 71E in the present embodiment is press-fitted and fixed to the protruding portion 223 of the lower bracket 22.

  The accommodating portions 716E and 717E each have a bottomed cylindrical shape. The circumferential positions of the storage portions 716E and 717E coincide with the circumferential positions of the openings 228 of the lower bracket 22. In the present embodiment, the accommodating portions 716E and 717E are arranged at three points in the circumferential direction and point-symmetrically. Further, the radial positions of the accommodating portions 716E and 717E coincide with the radial positions of the openings 228 of the lower bracket 22. Each accommodating part 716E, 717E is opened toward each opening part 228, respectively. Therefore, when the screw is inserted into the opening 228, each of the accommodating portions 716E and 717E can accommodate the screw. Accordingly, it is possible to prevent dust from entering the motor. Here, the circumferential positions of the accommodating portions 716E and 717E are located between the adjacent magnetic pole teeth 232 of the stator core 23, respectively. Further, the axial positions of the bottoms of the accommodating portions 716E and 717E are located closer to the stator core 23 than the axial positions of the annular portion 714E. By comprising in this way, the screw inserted in the opening part 228 can be lengthened.

<3-5. Other variations>
In this embodiment, the three-phase brushless motor is used, but the present invention is not limited to this. A single-phase or two-phase brushless motor may be used. Moreover, the motor with a brush which has a brush and a commutator may be sufficient. Moreover, you may use for other types of motors, such as a stepping motor.

  In the present embodiment, the protruding portion is annular, but is not limited thereto. Other shapes such as a flat plate shape may be used.

  In the present embodiment, the shape of the upper bracket 21 is such that the upper bearing is positioned radially inward of the central opening, but the present invention is not limited to this.

  Further, the object to be rotated may be fixed to either the upper side or the lower side of the shaft 31, or may be fixed to both. Further, the upper insulator 25 and the lower insulator 26 may be arranged in reverse.

  Moreover, you may combine suitably each element which appeared in said embodiment and modification in the range which does not produce inconsistency.

  The present invention can be used for an inner rotor type motor.

DESCRIPTION OF SYMBOLS 1 Motor 2 Rest part 21 Upper bracket 211 Cover part 212 Holding part 2121 Inner peripheral surface 2122 Top surface 213 Protrusion part 214 Through hole 2141 Seat surface 215 Opening 216 Protrusion part 228 Opening part 23 Stator core 231 Core back 232 Magnetic pole tooth 233 Through hole 234 Longitudinal groove 24 Coil 25 Upper insulator 251 Magnetic pole tooth insulating part 252 Core back insulating part 253 Annular wall part 2531 Seat surface 254 Positioning convex part 2541 (first) window part 255 flange part 2552 (second) window part 256 fixing member Insertion recess 26 Lower insulator 261 Lower magnetic pole tooth insulating part 2611 Plate part 262 Lower core back insulating part 2621 Lower core back insulating protruding part 2623 Coil guide wall 2624 Crossing line guide wall 2625 Continuous wall 2626 Crossing line holding part 2628 Inclining part 2629 Center part 27 Circuit board 271 Magnetic sensor Sa 272 positioning unit 273 Connector 274 hook insertion part 275 fixing member insertion portion 276 central opening 28 the bearing portion 281 above the bearing 282 lower bearing 29 armature 31 shaft 32 rotor holder 321 central 322 tubular portion 33 the rotor magnet 71 the cover member

Claims (9)

A shaft that is supported rotatably by a bearing member around a central axis extending vertically
A rotor magnet that rotates with the shaft;
An armature located radially outside the rotor magnet;
A casing for holding an upper bearing and a lower bearing for fixing the armature and rotatably supporting a shaft at a radial center;
Have
The armature is
A stator core including an annular core back and a plurality of magnetic pole teeth projecting radially inward from the core back;
An insulator covering at least an upper surface and a lower surface of the magnetic pole teeth of the stator core;
A coil configured by winding a conductive wire around the magnetic pole teeth via the insulator;
Have
The casing has an opening that is a hole penetrating in an axial direction on an axial end surface;
A cover member disposed between the casing and the armature at a position facing the opening;
The motor, wherein an upper surface of the cover member is in contact with at least a part of the armature. The upper surface of the cover member is in contact with the coil,
The motor according to claim 1, wherein the cover member is formed of an elastic body. The casing has an upper bracket that holds an upper bearing, and a lower bracket that holds a lower bearing,
The lower bracket is
A substantially circular flat plate-shaped lower lid,
A substantially cylindrical lower projecting portion projecting axially upward from the radially outer side of the lower lid portion;
Have
The motor according to claim 1, wherein an outer peripheral surface of the cover member is fixed to an inner peripheral surface of the lower projecting portion. The casing has an upper bracket that holds an upper bearing, and a lower bracket that holds a lower bearing,
The lower bracket is
A substantially circular flat plate-shaped lower lid,
A substantially cylindrical lower projecting portion projecting axially upward from the radially outer side of the lower lid portion;
Have
The cover member is
On the radially inner side of the opening, a collar extending downward in the axial direction;
On the radially outer side of the opening, a thick part having a thick axial thickness,
Located on the outside in the radial direction of the thick part, and a hem part having a thinner axial thickness than the thick part,
Have
The motor according to any one of claims 1 to 3, wherein the collar portion is in contact with the lower lid portion.   5. The motor according to claim 4, wherein a part of the inner peripheral surface of the collar portion has an inclined portion whose axial height decreases as it goes radially inward.   The motor according to claim 4 or 5, wherein the cover member is inserted into an inner peripheral surface of the lower protrusion at the skirt.   7. The cover member according to claim 1, wherein the cover member includes a plurality of accommodating portions having a bottomed cylindrical shape that coincides with radial and circumferential positions of the opening and opens toward the opening. The motor according to claim 1. The cover member has a disc shape, and further includes an annular portion that connects the plurality of the accommodating portions,
The circumferential position of the accommodating portion is located between the adjacent magnetic pole teeth of the stator core,
The motor according to claim 7, wherein a position in the axial direction of the bottom of the housing portion is located closer to the stator core than a position in the axial direction of the annular portion. The motor according to any one of claims 1 to 8, wherein a thread groove is formed on an inner peripheral surface of the opening.

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