JP2020005460A - motor - Google Patents

Abstract

To provide a motor which has a simple structure of a bearing holding member and achieves high rotation accuracy.SOLUTION: A motor includes: a rotor 1 having a shaft 11 extending along a center axis; a stator 2 facing the rotor in a radial direction; bearings Br1, Br2 rotatably supporting the shaft; an insulation member 3 covering a part of the stator; and a circuit board 5 which is disposed at a spacing from a lower part of the stator in an axial direction. The stator includes: a stator core including an annular core back 211 and teeth 212; and a coil 22. The insulation member includes: a core back cover part covering the core back 211; a teeth cover part 32 covering the teeth; and a holding part 33 which extends from an axial lower end part of the core back cover part to the center axis and holds the bearing Br1.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a motor.

  In the DC brushless motor described in Patent Document 1, the front side of the rotating shaft is rotatably supported via a front bearing, and the rear side is rotatably supported via a rear bearing. The front bearing is held by a bearing holding portion provided on a rear surface of an intermediate partition wall that partitions the inside of the main body case back and forth. The rear bearing is attached to a bearing holding member.

  The bearing holding member includes a bearing holding portion that holds the rear bearing, and three mounting edges that protrude outward in the radial direction from three equally spaced positions around the bearing holding member. The mounting edge is fixed to the electric insulating member with a screw.

JP 2012-257452 A

  However, the electric blower described in Patent Literature 1 requires a configuration for fixing screws and the like, and the number of parts increases. In addition, there is a possibility that the rotational axis may be misaligned, tilted, or the like due to the positioning accuracy at the time of fixing, which may cause a decrease in the rotational accuracy of the motor. Furthermore, the screw may be loosened due to vibration during rotation of the rotor, which also causes a reduction in the rotation accuracy of the motor.

  An object of the present invention is to provide a motor having a simple configuration and high rotation accuracy.

  An exemplary motor of the present invention includes a rotor, a stator, a bearing, an insulating member, and a circuit board. The rotor has a shaft extending along a central axis extending vertically. The stator is radially opposed to the rotor. The stator is formed of a stator core including an annular core back, a plurality of teeth extending radially inward from a radially inner peripheral portion of the core back, and a conductor, and an end of the conductor is connected to the circuit board. And a coil. The bearing rotatably supports the shaft. The insulating member covers a part of the stator. The insulating member covers the core back, covers the teeth, covers the teeth, and covers the teeth, and the coil is wound around the core back. And a holding unit for holding. The circuit board is disposed with a gap in the axial direction from the lower portion of the stator.

  According to the exemplary motor of the present invention, a motor having a simple configuration and high rotation accuracy can be provided.

FIG. 1 is a perspective view of a motor according to one embodiment. FIG. 2 is a perspective view of the motor shown in FIG. 1 as viewed from below. FIG. 3 is a cross-sectional view cut along a plane including the central axis of the motor shown in FIG. FIG. 4 is an exploded perspective view of the motor shown in FIG. FIG. 5 is a sectional perspective view of the stator core and the insulating member. FIG. 6 is a perspective view of the stator and the insulating member. FIG. 7 is a bottom view of the stator and the insulating member shown in FIG. FIG. 8 is a bottom view of another example of the stator and the insulating member. FIG. 9 is a bottom view of the motor. FIG. 10 is an enlarged perspective view of the projection. FIG. 11 is an enlarged view of a leg portion and an extension portion. FIG. 12 is a schematic cross-sectional view of a blower that is an external device using the motor according to the present embodiment.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. In this specification, in the motor A, a direction parallel to the central axis C of the motor A is referred to as an “axial direction”, a direction orthogonal to the central axis C of the motor A is referred to as a “radial direction”, and a central axis C of the motor A is referred to as a “radial direction”. The directions along the center arc are respectively referred to as “circumferential directions”. Further, in the present specification, in the motor A, the axial direction is defined as the up-down direction, and “up-down” is defined based on the up-down direction in FIG. Note that “up” and “down” are directions defined for ease of description, and do not limit the actual installation state of the motor A. It also includes cases where the vertical direction does not coincide with the direction of gravity.

(1st Embodiment)
<1. Overall Configuration of Motor>
FIG. 1 is a perspective view of a motor according to one embodiment. FIG. 2 is a perspective view of the motor shown in FIG. 1 as viewed from below. FIG. 3 is a cross-sectional view cut along a plane including the central axis of the motor shown in FIG. FIG. 4 is an exploded perspective view of the motor shown in FIG. FIG. 5 is a sectional perspective view of the stator core and the insulating member. FIG. 6 is a perspective view of the stator and the insulating member. FIG. 7 is a bottom view of the stator and the insulating member shown in FIG. FIG. 8 is a bottom view of another example of the stator and the insulating member. FIG. 9 is a bottom view of the motor. FIG. 10 is an enlarged perspective view of the projection. FIG. 11 is an enlarged view of a leg portion and an extension portion. FIG. 12 is a schematic cross-sectional view of a blower that is an external device using the motor according to the present embodiment.

  As shown in FIGS. 1 to 4, the motor A includes a rotor 1, a stator 2, an insulating member 3, an upper plate 4, and a circuit board 5. A part of the stator 2 is covered with the insulating member 3. A circuit board 5 is provided below the stator 2 in the axial direction. Electric power is supplied from the circuit board 5 to a coil 22 described later provided in the stator 2, and the rotor 1 rotates. In the motor A, the rotor 1 is arranged inside the stator 2 in the radial direction. That is, the motor A is an inner rotor type motor. Hereinafter, details of each part of the motor A will be described.

<1.1 About Rotor 1>
As shown in FIGS. 3 and 4, the rotor 1 includes a shaft 11, a rotor housing 12, a molded part 13, and a rotor magnet 14. The shaft 11 has a columnar shape extending along the central axis. The rotor housing 12 is a cylindrical body that extends in the axial direction along the central axis C. Then, the shaft 11 passes through the center of the rotor housing 12 (see FIG. 3).

  The mold part 13 is a resin molded body. The mold part 13 is provided between the shaft 11 and the rotor housing 12. The mold part 13 fixes the shaft 11 and the rotor housing 12. Further, the mold section 13 maintains a radial interval between the shaft 11 and the rotor housing 12.

  In the rotor magnet 14, N poles and S poles are alternately arranged in the circumferential direction. The rotor magnet 14 is cylindrical. The rotor magnet 14 is fixed radially outside the rotor housing 12. The rotor magnet 14 is a cylindrical body formed integrally with a resin containing a magnetic powder. The rotor magnet 14 has N and S poles alternately magnetized. The fixing of the rotor magnet 14 to the rotor housing 12 may be performed by press-fitting, bonding, or the like. Further, when molding the molded portion 13, the rotor magnet 14 may be fixed together with the rotor housing 12 by the molded portion 13. Although a single annular magnet is used as the rotor magnet 14, a plurality of magnets may be fixed to the outer surface of the rotor housing 12.

  The shaft 11 of the rotor 1 is attached to a lower bearing Br1 held by the insulating member 3 and an upper bearing Br2 held by the upper plate 4. Thereby, the shaft 11 and the rotor 1 including the shaft 11 are rotatably supported by the stator 2 and the insulating member 3.

<1.2 Stator 2>
As shown in FIGS. 5 to 7, a part of the stator 2 is covered with the insulating member 3. The stator 2 includes a stator core 21 and a coil 22.

<1.2.1 Stator core 21>
The stator core 21 may be a laminated body in which magnetic plates are laminated in the axial direction, or may be, for example, a molded body formed by sintering a powder to form the same member. Stator core 21 includes a core back 211 and a plurality of teeth 212. The core back 211 is annular.

  The plurality of teeth 212 extend radially inward from the radially inner peripheral portion of the core back 211. That is, the stator 2 includes a stator core 21 including an annular core back 211 and a plurality of teeth 212 extending radially inward from a radially inner peripheral portion of the core back 211. The plurality of teeth 212 are arranged at equal intervals in the circumferential direction. A flange 2121 that extends in the circumferential direction is provided on the radially inner side of the tooth 212. The flange portion 2121 has a radially inner surface 2122 having a curved surface centered on the central axis, and faces the rotor magnet 14 of the rotor 1 with a gap therebetween. Here, stator core 21 includes four teeth 212. That is, the stator core 21 has four slots. That is, the motor A of the present embodiment is an AC motor.

<1.2.2 About coil 22>
The coil 22 is formed by winding a conductive wire around a tooth 212 covered by a later-described tooth covering portion 32 of the insulating member 3. The coil 22 is formed on each of the four teeth 212. The four coils 22 are connected to each other. That is, the coil 22 is formed by a single connected conductor. Then, both ends of the conductor forming the coil 22 are connected to the circuit board 5. In the motor A of the present embodiment, an end of the coil 22 is connected to a conductive pin Bb disposed on a rod. The pin Bb is connected to the circuit board 5, and the end of the coil 22 is electrically connected to the circuit board 5. That is, the coil 22 is formed by a conductor, and the end of the conductor is connected to the circuit board 5.

<1.3 About insulating member 3>
The insulating member 3 covers a part of the stator 2. The insulating member 3 includes a core back covering part 31, a teeth covering part 32, a holding part 33, and a convex part 34. The insulating member 3 is made of, for example, a material having an insulating property such as a resin and easily formed. As shown in FIG. 5, the core back cover 31 covers the core back 211 of the stator 2.

<1.3.1 Regarding core back covering portion 31>
As shown in FIG. 5 and the like, the core back cover 31 covers the upper and lower portions of the core back 211 in the axial direction. The core back cover 31 also covers the radially inner peripheral portion of the core back 211 between the adjacent teeth 212. That is, the core back covering portion 31 covers the radially inner peripheral portion between the upper and lower portions in the axial direction of the core back 211 and the teeth 212. The radial outer surface 2111 of the core back 211 is exposed outside the insulating member 3. That is, at least a part of the radially outer surface of the core back 211 is exposed outside the insulating member 3.

  Thereby, heat generated in the stator core 21 and the coil 22 when the motor A is driven is easily released from the radial outer surface 2111 to the outside. Although details will be described later, the motor A rotates the impeller 6 for blowing air. The air flow (air flow) generated by the rotation of the impeller 6 flows in the axial direction along the radially outer surface 2111 of the core back 211. Since the radial outer surface 2111 is exposed from the insulating member 3, the radial outer surface 2111 is cooled by the airflow. Thereby, the temperature rise of the stator 2 and the motor A as a whole is suppressed.

<1.3.2 Regarding the teeth covering portion 32>
The teeth covering part 32 covers at least a part of the teeth 212. More specifically, the teeth covering portion 32 covers both ends of the teeth 212 in the axial direction and both ends in the circumferential direction. That is, the radial inner surface 2122 of the flange portion 2121 of the tooth 212 is not covered with the tooth covering portion 32. Thereby, the gap between the teeth 212 and the rotor magnet 14 can be reduced. Further, a radial inner surface 2122 of the flange portion 2121 is exposed outside the insulating member 3. As a result, the magnetic force acting between the teeth 32 and the rotor magnet 14 increases. From the above, it is possible to increase the rotation efficiency of the motor A.

  The teeth covering portion 32 is a molded body molded from the same member as the core back covering portion 31. This makes it possible to reduce the number of components.

<1.3.3 Regarding holding unit 33>
The holding portion 33 extends from the lower end in the axial direction of the core back covering portion 31 toward the central axis. The holding unit 33 holds the lower bearing Br1. That is, the holding portion 33 extends from the lower end in the axial direction of the core back covering portion 31 toward the central axis and holds the bearing Br1.

  The holding section 33 includes a tubular section 331 and a connecting section 332. The cylindrical portion 331 has a cylindrical shape extending parallel to the central axis. As shown in FIG. 3 and the like, the radially inner surface of the cylindrical portion 331 holds the radially outer surface of the outer ring of the lower bearing Br1. The lower bearing Br1 is a ball bearing, and a ball is disposed between the outer ring and the inner ring.

  The outer ring is held by the cylindrical portion 331, and the lower bearing Br1 is fixed to the holding portion 33. That is, the cylindrical portion 331 holds at least a part of the radially outer surface of the bearing Br1. As a result, the center of the lower bearing Br1 overlaps with the center axis C. The shaft 11 is fixed to the inner ring of the lower bearing Br1. Thus, the shaft 11 is rotatably supported by the lower bearing Br1.

  The outer ring of the lower bearing Br1 is fixed, for example, by press-fitting the cylindrical portion 331. However, it is not limited to this. The outer ring of the lower bearing Br1 may be fixed to the cylindrical portion 331 by welding, bonding, or the like, and a method capable of accurately fixing the center of the lower bearing Br1 to the center axis C by overlapping can be widely adopted. In the present embodiment, a ball bearing is adopted as the lower bearing Br1, but it is not limited to this. A bearing having a structure capable of rotatably supporting the shaft 11 can be widely used.

  The holding part 33 further includes a bottom part 333 and a protruding part 334. The bottom 333 extends from the lower end in the axial direction of the cylindrical portion 331 toward the central axis C. The bottom 333 has a flat plate shape orthogonal to the central axis C. The protruding portion 334 protrudes axially downward from the lower surface of the bottom portion 333. That is, the holding portion 33 includes a bottom portion 333 extending from the lower end portion in the axial direction toward the central axis C, and a projecting portion 334 projecting downward from the lower surface of the bottom portion 333 in the axial direction. As shown in FIGS. 2 and 3, the protrusion 334 has a cylindrical shape, and its center overlaps with the central axis C. That is, the protruding portion 334 extends axially downward from the radially central portion of the bottom portion 333. Although details will be described later, the circuit board 5 can be positioned in the radial direction.

  Further, the protruding portion 334 includes a rib 335 extending in the axial direction on the outer surface in the radial direction. As will be described in detail later, this allows the circuit board to be positioned in the circumferential direction.

  As shown in FIG. 7, in the insulating member 3, four connecting portions 332 are provided for connecting the core back cover 31 and the cylindrical portion 331. That is, a plurality of connecting portions 332 are provided. And the connection part 332 is arrange | positioned at equal intervals in the circumferential direction. Since the connecting portions 332 are arranged at equal intervals, vibration, blurring, and the like of the shaft 11 can be suppressed. Therefore, the rotation accuracy of the motor A can be improved. Further, in the present embodiment, the holding portion 33 has a configuration in which the thin plate-shaped connecting portion 332 is disposed as viewed from the axial direction, but is not limited thereto. For example, an annular shape that covers the axial lower portion of the stator 2 may be used.

  In the present embodiment, the number of the connection portions 332 is the same as the number of the teeth 212. If the number of the connecting portions 332 is equal to the number of the teeth 212, the cylindrical portion 331 can be firmly fixed by the connecting portion 332 while suppressing the insulating member 3 from having a complicated structure.

  The connecting part 332 includes a first connecting part 3321 and a second connecting part 3322. The first connecting portion 3321 extends in the axial direction from the lower end in the axial direction of the core back covering portion 31. The second connecting portion 3322 extends radially inward from an axial lower end of the first connecting portion 3321. That is, the connecting portion 332 includes a first connecting portion 3321 extending in the axial direction from the axial lower end of the core back covering portion 31 and a second connecting portion 3322 extending radially inward from the axial lower end of the first connecting portion 3321. And.

  Since the connecting portion 332 includes the first connecting portion 3321, the cylindrical portion 331 can be arranged to be spaced downward in the axial direction. Accordingly, the axial length of the lower bearing Br1 and the upper bearing Br2 can be increased, and the rotational accuracy of the shaft 11 can be increased. Further, the distance of the circuit board 5 from the stator 2 can be increased. Thereby, the circuit board 5 and the electronic components mounted on the circuit board 5 are hardly affected by the heat of the stator 2. Further, a space is provided around the teeth 212. Therefore, the heat of the stator 2 can be radiated from the space to the outside.

  The first connecting portion 3321 and the second connecting portion 3322, that is, the connecting portion 332 are arranged between the teeth 212 which are adjacent in the circumferential direction when viewed in the axial direction. Thereby, when winding a conductive wire around the teeth 212, a jig, a machine, or the like can be inserted. That is, it is easy to secure a space for winding the coil. Therefore, formation of the coil 22 becomes easy. Further, in each portion of the insulating member 3, there is no portion overlapping in the axial direction when viewed in the axial direction. Therefore, the insulating member 3 can be molded by using a die that is pulled upward in the axial direction and a die that is pulled downward in the axial direction. Thereby, the mold can be simplified, and the labor and time required for manufacturing the insulating member 3 can be reduced.

  Further, as shown in FIG. 7 and the like, the second connecting portion 3322 connects the lower end portion in the axial direction of the first connecting portion 3321 and the cylindrical portion 331. The first connecting portion 3321 and the second connecting portion 3322 have the same width in the circumferential direction. The circumferential width of the first connecting portion 3321 and the second connecting portion 3322 is smaller than the interval between the flange portions 2121 of the teeth 212 adjacent in the circumferential direction. That is, the circumferential width of the connecting portion 332 is smaller than the minimum distance between the teeth 212 adjacent in the circumferential direction. By reducing the width of the connecting portion 332, the circumferential length of the insulating member that covers the radially inner end of the teeth 212 extending in the circumferential direction can be increased. Thereby, more conductive wires can be wound around the teeth 212. Therefore, it is possible to suppress the deterioration of the characteristics of the motor A.

<1.3.4 Convex portion 34>
As shown in FIG. 5, FIG. 7, etc., the plurality of protrusions 34 extend radially outward from the core back cover 31. The protrusion 34 has a portion located radially outside the outer edge of the circuit board 5 when viewed from the axial direction. The convex portion 34 includes a mounting portion 35. That is, the insulating member 3 includes the mounting portion 35. Since the mounting portion 35 is formed of an insulating material, the weight of the motor A can be reduced. In the present embodiment, the insulating member 3 includes a pair of convex portions 34. The pair of projections 34 are axially symmetric with respect to the central axis C.

<1.3.5 Mounting part 35>
The attachment portion 35 is provided at a portion of the protrusion 34 located radially outside the outer edge of the circuit board 5. The mounting portion 35 is fixed to an external device F described later.

  As shown in FIG. 12, the fixing tool is, for example, a screw Sc. The mounting portion 35 includes a mounting through hole 351 through which the screw Sc passes. Then, as shown in FIG. 3, FIG. 7, etc., a hole 352 having a larger diameter than the mounting through hole 351 is provided on the upper surface of the projection 34 when viewed from the axial direction. Further, the mounting portion 35 includes a groove 353 extending from the radially outer surface of the projection 34 toward the hole 352.

  In addition, as shown in FIG. 8, the mounting portion 35 may include a notch 354 that is recessed radially inward from a radially outer edge. Note that the direction in which the notch 354 is recessed is not limited to the radial inside, and may be, for example, the circumferential direction.

<1.3.6 Regarding leg 36 and extension 37>
As shown in FIG. 10, the convex portion 34 includes a leg portion 36 protruding from the lower end portion in the axial direction toward the axial direction, and an extending portion 37. The leg 36 protrudes axially downward from the axial lower end of the projection 34. A board fixing portion 361 is provided at the lower end in the axial direction of the leg portion 36. The extending portion 37 extends axially downward from the lower end portion in the axial direction of the convex portion 34 toward the circuit board 5.

  The leg 36 has a flat plate shape extending in parallel with the axial direction, and is elastically deformable. The leg 36 has a circumferential width smaller than a radial width. That is, the leg 36 is elastically deformable in the circumferential direction. The board fixing portion 361 is disposed at the lower end in the axial direction of the leg 36. However, the direction in which the legs 36 are arranged is not limited to the direction shown in FIG.

  As shown in FIGS. 9 and 10, the board fixing portion 361 protrudes from the lower end in the axial direction of the leg 36 in a direction intersecting with the axial direction, that is, in the circumferential direction. The board fixing portion 361 protrudes along the direction in which the leg portion 36 is elastically deformed. The substrate fixing part 361 includes an inclined part 362 and a contact part 363. The contact portion 363 contacts the lower surface in the axial direction of the circuit board 5. That is, the insulating member 3 includes the leg portion 36 that protrudes downward in the axial direction, and the leg portion 36 includes a board fixing portion 361 that contacts the lower surface in the axial direction of the circuit board 5 at a lower portion. Thereby, the insulating member 3 has three functions of insulation between the stator core 21 and the coil 22, holding of the bearing Br1, and fixing of the circuit board 5. Therefore, there is no need to provide a separate member specialized for each function, and the number of components can be reduced.

  The inclined portion 362 has an inclined surface that expands in the circumferential direction from the lower part in the axial direction to the upper part. The contact portion 363 is arranged at the upper end in the axial direction of the inclined portion 362. The contact portion 363 has, for example, a plane orthogonal to the central axis C. The leg 36 penetrates a circuit board concave portion 51 described later provided on the circuit board 5. Then, the contact portion 363 of the board fixing portion 361 contacts the edge of the circuit board recess 51. Thereby, the insulating member 3 and the circuit board 5 are fixed. The details of fixing the insulating member 3 to the circuit board 5 will be described later. When the circuit board 5 is attached to the motor A by the board fixing section 361, the circuit board 5 comes into contact with the extending section 37. Therefore, the circuit board 5 is positioned in the axial direction. Further, the load on the substrate fixing portion 361 can be reduced. Thereby, workability of assembling the motor A is improved.

  The extension unit 37 includes a first extension unit 371 and a second extension unit 372. The first extending portion 371 is adjacent to the leg 36 in the circumferential direction. The second extension 372 is radially adjacent to the leg 36. By arranging the leg portion 36 and the extension portion 37 adjacent to each other, when the circuit board 5 and the insulating member 3 are fixed, the extension portion 37 bears a load (stress) concentrated on the leg portion 36. Therefore, the inclination of the circuit board 5 due to the load can be suppressed. The lower end surface of the first extension portion 371 and the lower end surface of the second extension portion 372 are in contact with the upper surface of the circuit board 5. Note that the lower end surface of the first extension portion 371 and the lower end surface of the second extension portion 372 may not be in contact with the circuit board 5, and a gap may be formed between the lower end surface and the circuit board 5. Since the convex portion 34 includes the two extending portions 371 and 372, the load on the substrate fixing portion 361 in the circumferential direction and the radial direction can be reduced. Thereby, the effect of holding the circuit board 5 by the board fixing portion 361 is enhanced.

  When the lower end surface of the extension 37 contacts the upper surface of the circuit board 5, the circuit board 5 is pushed in the axial direction by the extension 37 when the circuit board 5 and the insulating member 3 are fixed. Therefore, the insulating member 3 and the circuit board 5 can be fixed with high accuracy. Further, even when a gap is formed, the circuit board 5 is deformed when the circuit board 5 and the insulating member 3 are fixed, and the circuit board 5 comes into contact with the lower end surface of the extending portion 37, so that the circuit board 5 is Positioned in the axial direction. Thereby, workability in assembling the motor A is improved.

  The lower end portions in the axial direction of the first extending portion 371 and the leg portion 36 are adjacent to each other with the first concave portion 373 recessed in the axial direction interposed therebetween (see FIG. 10). The second extending portion 372 and the leg 36 are adjacent to each other with a second recess 374 recessed in the axial direction (see FIG. 10). Provision of the concave portion 373 (374) can suppress the propagation of stress between the leg portion 36 and the extending portion 37. Thus, it is possible to prevent the function from being insufficiently used due to the influence of the stress from the other side.

  As described above, when the leg portion 36 is bent by the leg portion 36 and the first extension portion 371 being adjacent to each other with the first recess portion 373 interposed therebetween, the displacement of the leg portion 36, that is, the stress is reduced by the first extension portion. 371. Therefore, when the leg portion 36 is elastically deformed, the first extending portion 371 is not easily deformed. Thereby, the axial position of the lower end surface of the first extension portion 371 is less likely to be shifted, and the positioning accuracy of the circuit board 5 in the axial direction can be increased. In addition, the elastic deformation of the leg 36 is less likely to be hindered by the first extension 371.

  Similarly, since the leg 36 and the second extension 372 are adjacent to each other with the second recess 374 interposed therebetween, when the leg 36 is bent, the displacement of the leg 36, that is, the stress is reduced by the second extension 372. It is difficult to be transmitted to. Therefore, when the leg portion 36 is elastically deformed, the second extending portion 372 is not easily deformed. Accordingly, the axial position of the lower end surface of the second extending portion 372 is less likely to be shifted, and the positioning accuracy of the circuit board 5 in the axial direction can be increased. In addition, the elastic deformation of the leg 36 is less likely to be hindered by the second extension 372.

  As described above, the two convex portions 34 are arranged at positions that are axially symmetric with respect to the center axis C. Further, the leg portions 36 and the extending portions 37 provided on the respective convex portions 34 are also axially symmetric with respect to the central axis C. With this arrangement, the circuit board 5 can be more stably fixed by the board fixing portion 361. Further, since the circuit board 5 is fixed at a position symmetrical with respect to the central axis C, the inclination of the circuit board 5 with respect to the axis can be suppressed.

<1.3.7 Guide unit 38>
As shown in FIGS. 1 and 4, the upper plate 4 is fixed to the upper surface 340 of the projection 34. The upper surface 340 of the projection 34 includes a pair of guides 38 arranged in the circumferential direction.

  As shown in FIG. 10, the pair of guide portions 38 has an inclined surface 381 at an upper portion in the axial direction. The inclined surface 381 of each of the pair of guide portions 38 has an inclination separated upward from the other. Note that the inclined surface 381 may be provided on both of the pair of guide portions 38 or may be provided on one of them. Thereby, the interval between the pair of guide portions 38 in the circumferential direction decreases toward the lower side in the axial direction. The first plate 431 described later of the upper plate 4 moves in the axial direction while being in contact with the inclined surface 381 of the guide portion 38, whereby the first plate 431 is positioned in the circumferential direction. Therefore, workability can be improved.

<1.4 About upper plate 4>
As shown in FIGS. 1 and 4, the upper plate 4 is attached to the upper surface 340 of the convex portion 34 of the insulating member 3. The upper plate 4 is made of metal. The upper plate 4 includes a beam portion 41, an upper bearing holding portion 42, and a support portion 43. The beam portion 41, the upper bearing holding portion 42, and the support portion 43 are integrally formed. However, the present invention is not limited to this, and may be an assembly formed by assembling each part formed as a separate member.

  The beam portion 41 has a plate shape extending in the radial direction of the central axis C. The beam portion 41 has a rectangular shape when viewed in the axial direction. The upper bearing holding portion 42 is arranged at a radially central portion of the beam portion 41. The upper bearing holding part 42 holds the upper bearing Br2. The upper bearing holding portion 42 has a bottomed cylindrical shape protruding upward in the axial direction. The upper bearing holding portion 42 has an upper shaft through hole 421 through which the shaft 11 passes at the center of the bottom.

  The upper bearing Br2 is a ball bearing, and a ball is arranged between the outer ring and the inner ring. Then, the outer race is fixed to the upper bearing holding portion 42, and the upper bearing Br2 is fixed to the upper bearing holding portion 42. Thus, the center of the upper bearing Br2 overlaps with the center axis C. The shaft 11 is fixed to the inner race of the upper bearing Br2. Thereby, the shaft 11 is rotatably supported by the upper bearing Br2. When the shaft 11 is rotatably supported by the upper bearing Br2, the shaft 11 passes through the upper shaft through-hole 421 of the upper bearing holding portion 42.

  The support 43 is connected to both ends of the beam 41 in the radial direction. The support portion 43 includes a first plate 431 and a second plate 432. The second plates 432 are arranged to face each other with the central axis C interposed therebetween. The first plate 431 is a flat plate extending radially outward from the lower end in the axial direction of the second plate 432.

  The first plate 431 is fixed to the upper surface 340 of the projection 34. The second plate 432 extends upward from a radially inner end of the first plate 431.

  The first plate 431 is provided with a plate through hole 433 penetrating in the axial direction at a central portion. The first plate 431 disposed on the upper surface 340 is guided by the inclined surface 381 and disposed on the upper surface 340. Then, the first plate 431 is fixed to the protrusion 34 by a screw Bt as a fastener.

  The upper plate 4 is fixed to the upper surface 340 of the projection 34 by passing a screw Bt through the plate through hole 433 of the first plate 431. Thereby, the upper plate 4 is fixed to the insulating member 3. At this time, the second plate 432 contacts a portion of the core back 211 exposed to the outside of the insulating member 3, that is, a radially outer surface of the core back 211. By bringing the upper plate 4 into contact with the fasteners Bt such as screws and the core back 211, the core back 211 and the fasteners Bt can be brought into electrical contact. Thereby, the stator core 21 can be easily grounded.

  The ground line GL is fastened to one of the first plates 431 of the upper plate 4 with a screw Bt. Thereby, the upper plate 4 is grounded. Further, the core back 211 that contacts the second plate 432 of the upper plate 4 is also grounded.

<1.4 About the circuit board 5>
The circuit board 5 is disposed below the insulating member 3 in the axial direction. That is, the circuit board 5 is disposed with a gap in the axial direction from the lower portion of the stator 2. The circuit board 5 is electrically connected to the plurality of coils 22. The circuit board 5 includes a drive circuit (not shown). That is, the coil 22 is formed by a conductor, and the end of the conductor is connected to the circuit board 5. The drive circuit supplies current to the plurality of coils 22 at appropriate timing.

  The circuit board 5 includes a through hole 50 and a circuit board recess 51. The circuit board 5 has a disk shape. The through hole 50 is formed at a radially central portion of the circuit board 5. That is, the circuit board 5 includes the through-hole 50 penetrating in the axial direction. The inner edge of the through hole 50 has a recess 501 that is recessed outward in the radial direction. That is, the circuit board 5 has the concave portion 501 that is recessed radially outward from the inner edge of the through hole 50.

  When the circuit board 5 is mounted below the insulating member 3 in the axial direction, the projecting portion 334 penetrates the through hole 50. The lower surface of the protrusion 334 is located axially below the lower surface of the circuit board 5. Note that the protrusion 334 does not have to penetrate the through-hole 50. For example, the lower surface of the protrusion 334 may be located between the upper surface and the lower surface of the circuit board 5 inside the through hole 50. That is, at least a part of the protrusion 334 is disposed inside the through-hole 50. Further, the rib 335 of the protruding portion 334 is arranged in the concave portion 501 of the through hole 50. That is, a part of the rib 335 is disposed in the recess 501. Thereby, the circuit board 5 is positioned in the circumferential direction.

  At this time, the leg 36 penetrates the circuit board recess 51 of the circuit board 5. Then, the upper surface of the contact portion 363 contacts the lower surface of the circuit board 5. Thereby, the movement of the circuit board 5 downward in the axial direction is restricted. At this time, the extending portions 37 (the first extending portion 371 and the second extending portion 372) come into contact with the upper surface of the circuit board 5. The circuit board 5 is held by the board fixing part 361 and the extension part 37.

<1.5 Manufacturing of Motor A>
In the present embodiment, the insulating member 3 is an integrally molded resin and covers the stator core 21. The resin molding of the insulating member 3 will be described. First, a stator core 21 prepared in advance is fixed inside a resin molding die. Then, a mold is filled with a molding resin. At this time, the outer surface of the core back 211 in the radial direction is brought into contact with the mold. Therefore, the radially outer surface of the core back 211 is not covered with the insulating member 3, that is, exposed to the outside. Similarly, the radial inner surface of the flange portion 2121 of the tooth 212 can also be exposed to the outside of the insulating member 3 by contacting the radial inner surface of the flange portion 2121 with the mold or the insert.

  After the resin is cured, the mold is removed, so that the insulating member 3 covers a part of the stator core 21. As described above, when viewed in the axial direction, the connecting portion 332 is disposed between the teeth 212 that are adjacent in the circumferential direction. Therefore, the mold includes a mold that is pulled upward in the axial direction and a mold that is pulled downward in the axial direction.

  Then, a conductive wire is wound around the teeth 212 covered by the teeth covering portion 32 of the insulating member 3 to form the coil 22. At this time, the circumferential width of the connecting portion 332 is smaller than the minimum distance between the teeth 212 adjacent in the circumferential direction. Thereby, when winding a conductive wire around the teeth 212, a jig, a machine, or the like can be inserted. That is, it is easy to secure a space for winding the coil. Therefore, formation of the coil 22 becomes easy.

  Then, after covering a part of the stator core 21 with the insulating member 3, the lower bearing Br1 is fixed to the cylindrical portion 331. The fixing method is not particularly limited, but here, press-fitting is performed. Further, the upper bearing Br2 is fixed to the upper bearing holding portion 42 of the upper plate 4. The fixing method is press-fitting as in the case of the lower bearing Br1. Then, the shaft 11 of the rotor 1 is held by the lower bearing Br1. Further, the shaft 11 is held by the upper bearing Br2 held by the upper plate 4. Then, the first plate 431 of the column portion 43 of the upper plate 4 is arranged on the upper surface 340 of the convex portion 34, and is fixed with a screw Bt as a fastener. At this time, the ground wire GL is jointly fastened to one screw Bt. Thus, the rotor 1 is rotatably supported by the stator 2.

  Then, the circuit board 5 is mounted axially from below the stator 2 on which the rotor 1 is supported. At this time, the circuit board 5 is positioned in the radial direction by inserting the protrusion 334 into the through hole 50 of the circuit board 5. At the same time, the circuit board 5 is positioned in the circumferential direction by inserting the rib 335 formed on the protrusion 334 into the recess 501. As a result, the circuit board recess 51 of the circuit board 5 overlaps the leg 36 in the axial direction. On the other hand, the board fixing portion 361 of the leg 36 axially overlaps with the edge of the circuit board recess 51.

  In this state, by moving the circuit board 5 upward in the axial direction, the inclined portion 362 of the board fixing portion 361 is pressed at the edge of the circuit board recess 51. Then, the leg portion 36 is elastically deformed by the force. When the board fixing portion 361 is lower than the lower surface of the circuit board 5, the contact between the inclined portion 362 and the edge of the circuit board concave portion 51 is released, and the elastically deformed leg portion 36 becomes Return to the original shape. Then, the contact portion 363 of the board fixing portion 361 contacts the lower surface of the circuit board 5. As a result, the circuit board 5 is restricted from moving downward in the axial direction. Further, the circuit board 5 comes into contact with the lower surface of the extending portion 37. This suppresses the circuit board 5 from approaching too close to the stator 2, maintains the position of the circuit board 5 in the axial direction, and suppresses the inclination with respect to the axis.

  In the motor A described above, the insulating member 3 that covers a part of the stator core 21 and the holding portion 33 that holds the lower bearing Br1 are integrally formed. Accordingly, a fixture such as a screw for fixing the insulating member 3 and the holding portion 33 can be omitted, and the number of components can be reduced. Further, since the screwing work is not required, the number of working steps can be reduced. Further, the weight of the holding portion can be reduced as compared with a case where the holding portion is formed of a metal plate such as a sheet metal. Thus, the weight of the motor A can be reduced.

  By holding the lower bearing Br1 with the cylindrical portion 331 of the holding portion 33, the center lines of the stator 2 and the lower bearing Br1 can be aligned with the same line, here, the center axis C. That is, in mounting the lower bearing Br1, the work of aligning the stator 2 and the lower bearing Br1, that is, the work of centering can be omitted, so that the man-hour required for manufacturing can be reduced.

<3. Attachment of Motor A to External Device F>
An external device F to which the motor A according to the present invention is attached will be described with reference to the drawings. FIG. 12 is a cross-sectional view showing a state where the motor according to the present invention is attached to an external device. In the present embodiment, the external device F to which the motor A is attached is a blower that generates an airflow inside the wind tunnel 7.

  As shown in FIG. 12, the external device F includes a motor A, an impeller 6, and a wind tunnel 7. In the external device F, the motor A is housed inside the wind tunnel 7. The wind tunnel 7 is a cylindrical body extending in the axial direction. And the wind tunnel part 7 is provided with the fixed protrusion 71 extended in the radial direction inside in the radial direction inner surface.

  The motor A is housed inside the wind tunnel 7. Then, with the convex portion 34 and the fixing protrusion 71 overlapping in the axial direction, the screw Sc is inserted into the mounting portion 35 and fixed. At this time, since the head of the screw Sc is housed inside the hole 352, the head of the screw Sc does not protrude in the axial direction. Then, by fixing the nut Nt to a portion of the screw Sc protruding downward from the lower surface of the projection 34 in the axial direction, the fixing projection and the projection 34 are fixed. That is, the motor A is fixed inside the wind tunnel portion 7.

  However, the method of fixing the motor A is not limited to this. For example, the screw Sc may be inserted from below in the axial direction, the nut Nt may be arranged inside the hole 352 of the mounting portion 35, and the screw Sc and the nut Nt may be fixed. Furthermore, the screw Sc may be screwed into the fixing projection 71 to fix the fixing projection 71.

  In addition, the fixing protrusion 71 is disposed below the protrusion 34 in the axial direction, but may be disposed above. In this case, the fixing protrusion 71 may be disposed in the hole 352 and the groove 353. With this arrangement, the motor A can be prevented from rotating (positioning) during assembly. Thereby, workability can be improved.

  Further, a motor A provided with a mounting portion 35 having a notch 354 shown in FIG. 8 may be mounted. With this configuration, the motor A can be moved in the direction in which the notch 354 is recessed. Thereby, the position of the motor A with respect to the wind tunnel 7 can be adjusted. The fixing between the projection 34 and the fixing projection 71 is performed using a screw Sc that penetrates both the projection 34 and the fixing projection 71, but is not limited thereto. For example, a fixing tool such as a rivet may be used, or a screw provided in advance on the fixing protrusion 71 may be passed through the mounting portion 35 and fixed with a nut.

  The impeller 6 is fixed to the upper end of the shaft 11. The impeller 6 includes an impeller cup 61 and a plurality of blades 62. The impeller cup 61 has a columnar shape. A cylindrical boss (not shown) extending in the axial direction is provided inside the impeller cup 61. The shaft 11 is inserted and fixed inside the boss. Thereby, the impeller 6 is fixed to the shaft 11. Then, the impeller 6 is disposed inside the wind tunnel portion 7. The impeller 6 rotates around the central axis C together with the shaft 11. Each of the plurality of blades 62 is inclined in the circumferential direction. The plurality of blades 62 extend radially outward from the radially outer surface of the impeller cup 61. The plurality of blades 62 are arranged at equal intervals in the circumferential direction.

  In the external device F, when the motor A is driven, the shaft 11 rotates. The rotation of the shaft 11 rotates the impeller 6 around the central axis C. Due to the rotation of the impeller 6, an air flow, that is, an air flow, is generated from above to below in the axial direction inside the wind tunnel portion 7. More specifically, in the wind tunnel 7, the opening at the upper end in the axial direction is the intake opening 70I, and the opening at the lower end is the exhaust opening 70X. In the wind tunnel section 7, the rotation of the impeller 6 sucks air from the intake side opening 70I and discharges air from the exhaust side opening 70X.

  In the external device F, the inner wall surface of the wind tunnel portion 7 and the radial outer surface of the motor A face each other with a gap in the radial direction. In the external device F, an air flow flows through a radial gap between the inner wall surface of the wind tunnel 7 and the motor A. That is, a radial gap between the inner wall surface of the wind tunnel portion 7 and the motor A forms an air path. As described above, in the motor A, the radial outer surface 2111 of the core back 211 is exposed outside the insulating member 3. Therefore, when the motor A is attached to the wind tunnel portion 7, the radially outer surface 2111 of the core back 211 is exposed in the air passage. The radial outer surface 2111 of the core back 211 is cooled by the airflow. Thereby, the whole stator core 21 is cooled and the coil 22 is also cooled. Therefore, in the motor A, a decrease in performance due to a rise in temperature is suppressed.

  Further, in the motor A according to the present invention, the holding portion 33 holding the lower bearing Br1 is formed integrally with the insulating member 3 covering a part of the stator 2. Therefore, as compared with a configuration in which the holding portion 33 is provided as a separate member, the number of components and the number of assembling steps can be reduced.

  Although the embodiment of the present invention has been described above, the embodiment can be variously modified within the scope of the gist of the present invention.

  The motor of the present invention can be used, for example, as a driving device for an external device such as a dryer, a blower fan, and a vacuum cleaner.

DESCRIPTION OF SYMBOLS 1 Rotor 2 Stator 3 Insulating member 4 Upper plate 5 Circuit board 6 Impeller 7 Wind tunnel part 11 Shaft 12 Rotor housing 13 Mold part 14 Rotor magnet 21 Stator core 22 Coil 31 Core back covering part 32 Teeth covering part 33 Holding part 34 Convex part 35 Mounting Part 36 leg part 37 extension part 38 guide part 41 beam part 42 upper bearing holding part 43 support part 50 through hole 51 circuit board concave part 61 impeller cup 62 blade 70I intake side opening 70X exhaust side opening 71 fixing projection 211 core back 212 teeth 331 Cylindrical part 332 Connecting part 340 Upper surface 351 Mounting through hole 352 Hole 353 Groove 354 Notch 361 Board fixing part 362 Inclined part 363 Contact part 371 First extended part 372 Second extended part 373 First concave part 374 First Recess 381 Inclined surface 421 Upper shaft through hole 431 First plate 432 Second plate 433 Plate through hole 501 Recess 2111 Radial outer surface 2121 Flange 2122 Radial inner surface 333 Bottom 334 Projection 335 Rib 3321 First connection 3322 Second connection Part A Motor Bb Pin Br1 Lower bearing Br2 Upper bearing Bt Fastener Br1 Lower bearing Br2 Upper bearing C Central axis F External equipment GL Ground wire

Claims (12)

A rotor having a shaft extending along a vertically extending central axis;
A stator radially opposed to the rotor;
A bearing rotatably supporting the shaft;
An insulating member that covers a part of the stator;
A circuit board disposed with a gap between the lower part of the stator and the axial direction,
The stator is
An annular core back, and a stator core including a plurality of teeth extending radially inward from a radially inner peripheral portion of the core back,
A coil formed by a conductive wire, an end of the conductive wire being connected to the circuit board,
The insulating member,
A core back covering portion that covers the core back,
A teeth covering portion that covers the teeth and around which the coil is wound,
A holding portion that extends from a lower end portion in the axial direction of the core back covering portion toward a central axis and holds the bearing.   The motor according to claim 1, wherein at least a part of a radially outer surface of the core back is exposed outside the insulating member. The holding unit,
A cylindrical portion that holds at least a part of a radially outer surface of the bearing;
3. The motor according to claim 1, further comprising: a connecting portion that connects the core back covering portion and the cylindrical portion. 4. The connecting portion,
A first connecting portion extending in an axial direction from an axial lower end of the core back covering portion;
The motor according to claim 3, further comprising: a second connecting portion extending radially inward from an axial lower end of the first connecting portion.   The motor according to claim 3, wherein the connecting portion is disposed between the teeth adjacent in the circumferential direction when viewed from the axial direction.   The motor according to claim 5, wherein a circumferential width of the connecting portion is smaller than a minimum distance between the teeth adjacent in the circumferential direction. The connection unit is provided with a plurality,
The motor according to claim 3, wherein the connecting portions are arranged at equal intervals in a circumferential direction.   The motor according to claim 7, wherein the number of the connection portions is equal to the number of the teeth. The holding unit,
A bottom portion extending from the lower end portion in the axial direction toward the central axis,
A projection that projects axially downward from the lower surface of the bottom,
The circuit board includes a through hole that penetrates in an axial direction,
9. The motor according to claim 3, wherein at least a part of the protrusion is disposed inside the through hole. 10. The protrusion has a rib extending in the axial direction on a radially outer surface,
The circuit board has a recess that is recessed radially outward from an inner edge of the through hole,
The motor according to claim 9, wherein a part of the rib is disposed in the recess.   The motor according to claim 9, wherein a lower surface of the projecting portion is positioned axially below a lower surface of the circuit board. The insulating member includes a leg protruding downward in the axial direction,
The motor according to any one of claims 1 to 11, wherein the leg includes a circuit board fixing portion at a lower portion thereof, which is in contact with an axial lower surface of the circuit board.

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