JP2012178963A - Motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a fastening structure of a cover member of a motor and a mounting plate.SOLUTION: A motor 1 includes: bearings 113; a shaft 21 rotatably supported by the bearings 113 around a vertical central shaft; a bush 31 holding the bearings 113 on the inner side; a stator 321 fixed to the outer peripheral face of the bush 31; an approximately cylindrical bottomed rotor holder 221 fixed to the upper side of the shaft 21; a rotor magnet 23 fixed to the inner peripheral face of a cylindrical part of the rotor holder 221 and located on the radial outer side of the stator 321; a mounting plate 13 having a plate shape expanding from a lower end of the bush 31 to the radial outer side and including a mounting part used for mounting to a mounting target; and a cover member 12 having an approximately cylindrical bottomed shape which covers the rotor holder 221 and in which a lower end of a cylindrical part is fixed to the mounting plate.

Description

  The present invention relates to an electric motor.

  Conventionally, in home appliances such as an air cleaner and a ventilation fan, an inner rotor type motor is used as a drive source. A motor mounted on a home appliance needs a simple dustproof structure. In order to prevent dust and the like from entering the motor, for example, in an AC (Alternating Current) motor, the entire motor is resin-molded, and in a DC (Direct Current) motor, a cover member that covers the motor is attached.

Japanese Patent Laying-Open No. 2010-098815 discloses an outer rotor type DC brushless motor which is an in-vehicle fan motor. The motor includes a rotor, a stator, a motor shaft, a bearing portion, a cup-shaped bracket, and a mounting base. The rotor includes a cup-shaped rotor yoke and a rotor magnet. A bearing portion is attached to the inside of the hollow cylindrical portion formed in the bracket, and the motor shaft is pivotally supported by the bearing portion. A rotor yoke is fixed to the motor shaft, and a rotor magnet is bonded to the inner peripheral surface of the rotor yoke. A stator is fixed to the outer peripheral surface of the hollow cylindrical portion. The stator is located inside the rotor magnet. The bracket and the mounting base are assembled together by screw fixing. Other members of the motor are housed in a closed space formed by the bracket and the mounting base.
JP 2010-098815 A

  By the way, in the inner rotor type motor, since the inertia is small, the rotation tends to be unstable due to the influence from the outside. Also, swell sounds are likely to occur. Therefore, in recent years, it has been proposed to use an outer rotor type motor with high efficiency and high output for home appliances. In the motor disclosed in Japanese Patent Application Laid-Open No. 2010-098815, since the bracket supports the bearing portion and the stator, it is necessary to firmly fix the bracket to the mounting base so as to withstand vibration and drop impact. As a result, the design of the fastening structure between the bracket and the mounting base becomes complicated.

  An object of the present invention is to simplify a fastening structure between a cover member and a mounting plate of a motor.

  A motor according to an exemplary aspect of the present invention includes a bearing, a shaft that is rotatably supported by the bearing about a central axis that faces the vertical direction, a bush that holds the bearing inside, and the bush. A stator fixed to the outer peripheral surface of the rotor, a lid-shaped substantially cylindrical rotor holder fixed to the upper part of the shaft, and a rotor magnet fixed to the inner peripheral surface of the cylindrical portion of the rotor holder and positioned on the radially outer side of the stator And a plate extending from the lower end of the bush radially outward, an attachment plate having an attachment portion used for attachment to an attachment target, and a lid-like substantially cylindrical shape covering the rotor holder, A cover member fixed at the lower end to the mounting plate.

  ADVANTAGE OF THE INVENTION According to this invention, the fastening structure of the cover member and attachment plate of a motor can be simplified.

FIG. 1 is a cross-sectional view showing a motor according to the first embodiment. FIG. 2 is an exploded perspective view of the motor. FIG. 3 is a perspective view of the motor. FIG. 4 is a diagram illustrating a hook portion and a mounting plate of the cover member. FIG. 5 is a diagram illustrating a hook portion and a mounting plate of the cover member. FIG. 6 is a front view of the motor according to the second embodiment. FIG. 7 is an exploded perspective view of the motor. FIG. 8 is a perspective view showing a part of a motor according to another example.

  In the present specification, the upper side of FIG. 1 in the direction of the central axis of the motor is simply referred to as “upper side”, and the lower side is simply referred to as “lower side”. Note that the vertical direction does not indicate the positional relationship or direction when incorporated in an actual device. A direction parallel to the central axis is referred to as an “axial direction”, a radial direction centered on the central axis is simply referred to as “radial direction”, and a circumferential direction centered on the central axis is simply referred to as “circumferential direction”.

(First embodiment)
FIG. 1 is a cross-sectional view of a motor 1 according to an exemplary first embodiment of the present invention. The motor 1 is an outer rotor type, and is used as a drive source for home appliances such as an air purifier and a ventilation fan. The motor 1 includes a motor unit 11, a cover member 12, and a mounting plate 13. The motor unit 11 includes a rotating unit 111, a stationary unit 112, and two bearing members 113 that are ball bearings. The rotating part 111 rotates around a central axis J1 that faces the stationary part 112 in the vertical direction.

  The rotating unit 111 includes a shaft 21, a rotor holder 22, and a rotor magnet 23. In FIG. 1, the output side end of the shaft 21 faces downward. The rotor holder 22 has a substantially cylindrical shape with a lid, and is formed by pressing a thin plate. The upper portion of the shaft 21 is fixed to the hole provided in the center of the lid portion 221 of the rotor holder 22. The rotor magnet 23 is fixed to the inner peripheral surface of the cylindrical portion 222 of the rotor holder 22. The rotor magnet 23 may be cylindrical, or a plurality of magnets arranged in the circumferential direction.

  The stationary part 112 includes a bush 31, a stator 32, and a circuit board 33. The bush 31 is substantially cylindrical with the central axis J1 as the center. Bearing members 113 are inserted into the upper and lower portions of the inner peripheral surface of the bush 31. The shaft 21 is press-fitted inside the bearing member 113. In the motor unit 11, the shaft 21 is supported by the two bearing members 113 held inside the bush 31 so as to be rotatable about the central axis J1. The stator 32 includes a stator core 321 and a coil 322. The stator core 321 has an annular shape centered on the central axis J1, and is formed by stacking a plurality of thin magnetic steel plates in the vertical direction. A radially inner portion of the stator core 321 is fixed to the outer peripheral surface of the bush 31. The stator core 321 may be indirectly fixed to the bush 31. The coil 322 is formed by winding a conducting wire around the stator core 321. The rotor magnet 23 is located outside the stator 32 in the radial direction, and torque is generated between the stator 32 and the rotor magnet 23.

  The cover member 12 has a substantially cylindrical shape with a lid and covers the rotor holder 22. The cover member 12 is molded from resin. The attachment plate 13 has a disk shape that extends radially outward from the lower end of the bush 31 and is attached to an attachment target in a device such as a home appliance. The mounting plate 13 is made of metal. In the motor 1, the lower end 121 a of the cylindrical portion 121 of the cover member 12 is fixed to the mounting plate 13, thereby preventing dust and the like from entering the motor 1.

  FIG. 2 is an exploded perspective view of the motor 1. In the cover member 12, the lower end part 121a of the cylindrical part 121 is provided with the flange part 4 which spreads radially outward. The flange portion 4 is provided with three concave portions 41 that are recessed upward. The three concave portions 41 are provided at equal intervals in the circumferential direction. A hook portion 42 that protrudes downward is provided on the bottom 411 of the recess 41.

  The cylindrical portion 121 is provided with a notched portion 43 (hereinafter referred to as a “notched portion 43”) that is recessed upward. In the axial direction, the notch 43 overlaps a portion 331 that protrudes radially outward of the circuit board 33 (hereinafter, referred to as “substrate protrusion 331”). In a state where the cover member 12 is attached to the motor unit 11, the board protruding part 331 protrudes radially outward from the notch part 43. The board protrusion 331 is provided with a connector (not shown) connected to an external power source. Actually, the notch 43 and the substrate protrusion 331 are covered with a cap (not shown).

  The mounting plate 13 includes a stepped portion 5, three mounting holes 131, and three bush fixing holes 132. The step portion 5 protrudes upward in a trapezoidal shape at the outer edge portion 13 a of the mounting plate 13. An opening 51 is provided in the approximate center of the stepped portion 5. The three attachment holes 131 are provided in three portions 133 that protrude outward in the radial direction, and are arranged in the circumferential direction. The attachment plate 13 is attached to the attachment object by inserting a screw into the attachment hole 131 and the screw hole provided in the attachment object of the device. Thus, the attachment hole 131 plays a role as an attachment part used for attachment to an attachment target. The central portion 134 of the mounting plate 13 protrudes stepwise upward, that is, the lower surface 134a of the central portion 134 is the bottom surface of a portion that is recessed upward. The bush fixing hole 132 is provided in the central portion 134. In the following description, a portion around the central portion 134 is referred to as a “peripheral portion 135”.

  When the motor 1 is assembled, first, the motor unit 11 is assembled. Next, the shaft 21 is passed through the hole in the central portion 134 of the mounting plate 13 and the screw hole 311 provided at the lower end of the bush 31 and the bush fixing hole 132 are overlapped in the direction of the central axis J1. By inserting the screw 14 into the screw hole 311 and the bush fixing hole 132, the mounting plate 13 and the bush 31 are fixed at the central portion 134. As described above, since the lower surface 134a of the central portion 134 is recessed upward, the head of the screw 14 is prevented from protruding downward from the lower surface 135a of the peripheral portion 135 as shown in FIG. Is done.

  When the mounting plate 13 and the bush 31 are fixed, the cover member 12 and the mounting plate 13 are fixed so that the stepped portion 5 fits into the concave portion 41 as shown in FIG. The step part 5 and the recessed part 41 contact | abut in the circumferential direction and an axial direction. In the process of fitting the stepped portion 5 into the concave portion 41, as shown in FIG. 4, in the hook portion 42, a portion 421 a protruding outward in the radial direction of the tip portion 421 contacts the edge 511 at the upper end of the opening 51. As a result, the tip portion 421 moves inward in the radial direction due to elastic deformation of the hook portion 42. As shown in FIG. 5, when the distal end portion 421 moves to the lower side of the opening 51, the hook portion 42 returns to its original shape, and the portion 421 a is engaged with the edge 512 at the lower end of the opening 51 and the lower surface 51 a of the step portion 5. Match. That is, the upper surface of the tip portion 412 is in contact with or close to the lower surface 51a. Hereinafter, the lower surface 51 a of the step portion 5, the surface of which the normal line faces downward, the lower surface 135 a of the peripheral portion 135, and the lower surface 134 a of the central portion 134 of FIG.

  As described above, in the motor 1, the cover member 12 and the mounting plate 13 are easily fixed by engaging the hook portion 42 with the lower surface of the mounting plate 13 using elastic deformation. In the hook portion 42, the position of the lower end of the distal end portion 421 is positioned at the same height as the lower surface 135 a of the peripheral portion 135, that is, the lower surface of the portion around the step portion 5. Thereby, it can prevent that the hook part 42 interferes with the attachment object of the motor 1 in an apparatus. The lower end of the distal end portion 421 may be located above the lower surface 135a of the peripheral portion 135.

  As shown in FIG. 3, in the motor 1, the boundary 6 between the flange portion 4 of the cylindrical portion 121 and the outer edge portion 13 a of the mounting plate 13 exists over substantially the entire circumference centering on the central axis J <b> 1. However, the position where the notch 43 of FIG. 2 is provided is excluded. At the boundary 6, the flange portion 4 and the mounting plate 13 are shaped along each other. That is, the flange portion 4 and the mounting plate 13 abut or approach each other over the entire circumference, and the undulation of the flange portion 4 coincides with the undulation of the outer edge portion 13 a of the mounting plate 13. As a result, almost no gap occurs at the boundary 6. As a result, entry of dust or the like from the boundary 6 can be prevented or suppressed.

  As described above, the structure of the motor 1 according to the first embodiment has been described. However, in the motor 1, the cover member 12 does not support other parts such as the stationary portion 112. Thus, no large force is applied to the cover member 12. Further, since the cover member 12 is not provided with an attachment portion that is attached to the device, high strength is not required. For this reason, it is not necessary to firmly fix the cover member 12 and the mounting plate 13, and the fastening structure between the cover member 12 and the mounting plate 13 can be simplified. Design of the cover member 12 is also facilitated.

  In particular, the cover member 12 and the mounting plate 13 are easily fixed by using a snap-fit structure in which the hook portion 42 engages with the lower surface of the mounting plate 13 using elastic deformation as such a fastening structure. be able to. In addition, a dedicated facility for fastening the cover member 12 and the mounting plate 13 is not required. As a result, the manufacturing cost of the motor 1 can be reduced. The cover member 12 and the mounting plate 13 can be disassembled, and the maintenance of the motor 1 becomes easy. Compared with the case where the cover member 12 and the mounting plate 13 are fixed by screws, the number of parts can be reduced. In the motor 1, since the cover member 12 can be made thin, the motor 1 can be reduced in weight.

  In the mounting plate 13, the strength of the fixed portion can be improved by setting the portion with which the hook portion 42 is engaged as the stepped portion 5. In the cover member 12, a recess 41 that fits into the stepped portion 5 is provided around the hook portion 42. Thus, when the cover member 12 and the mounting plate 13 are fixed, even if a force that rotates the cover member 12 acts on the cover member 12, the cover member 12 may shift in the circumferential direction with respect to the mounting plate 13. Is prevented. As a result, it is possible to prevent a force from being applied in the circumferential direction to the hook portion 42 and to prevent the hook portion 42 from being damaged. Note that a circumferential gap may exist between the step portion 5 and the recess 41 within a range in which no force is applied to the hook portion 42.

(Second Embodiment)
FIG. 6 is a front view of the motor 1a according to the second embodiment. The motor 1a includes a cover member 12a formed of metal. FIG. 7 is an exploded perspective view of the motor 1a. In the cover member 12a, the lower end portion 121a of the cylindrical portion 121 includes a flange portion 4a that extends radially outward. The flange portion 4a is provided with a plurality of cutout portions (hereinafter referred to as “flange cutout portions 44”). The flange notches 44 are provided at equal intervals in the circumferential direction. The mounting plate 13 includes a plurality of protrusions 52 extending upward on the outer edge portion 13a. Actually, in a state where the motor 1a is assembled, the protrusion 52 is bent radially inward as shown in FIG. In FIG. 6, the state before the protrusion 52 is bent is indicated by a two-dot chain line. The other structure of the motor 1a is the same as that of the motor 1 according to the first embodiment. In the following description, the same components are denoted by the same reference numerals.

  When the motor 1 a is assembled, as shown in FIG. 7, the bush 31 of the motor unit 11 and the mounting plate 13 are fixed by screws 14. Next, while the cover member 12a covers the motor portion 11, the flange portion 4a and the outer edge portion 13a of the mounting plate 13 contact each other in the direction of the central axis J1. At this time, as shown in FIG. 6, the protrusion 52 of the mounting plate 13 is positioned above the flange portion 4 a via the flange cutout portion 44. The protrusion 52 is bent onto the upper surface 45 of the flange portion 4 a, that is, is plastically deformed and contacts the upper surface 45.

  In the motor 1a, the cover member 12a and the mounting plate 13 are easily fixed by using a caulking structure constituted by the protruding portion 52 and the flange portion 4a as a fastening structure between the cover member 12a and the mounting plate 13. The At the boundary 6 between the flange portion 4a and the mounting plate 13, the flange portion 4a and the mounting plate 13 are shaped along each other. As a result, entry of dust or the like from the boundary 6 can be prevented or suppressed.

  In the second embodiment, as in the first embodiment, a large force is not applied to the cover member 12a due to the vibration of the motor 1a. Further, the cover member 12a is not required to have high strength. For this reason, it is not necessary to firmly fix the cover member 12a and the mounting plate 13, and the fastening structure between the cover member 12a and the mounting plate 13 can be simplified.

  FIG. 8 is a perspective view of a part of the motor 1a showing another example of the protrusion. The length in the axial direction of the protrusion 52a shown in FIG. 8 is shorter than the protrusion 52 shown in FIG. The width of the protrusion 52 a in the circumferential direction is wider than that of the protrusion 52. Further, the flange cutout portion 44 shown in FIG. 7 is omitted from the flange portion 4a.

  When the cover member 12a and the mounting plate 13 are fixed, the center portion 521 of the protruding portion 52a is pressed onto the upper surface of the flange portion 4a by pressing in a state where the flange portion 4a and the mounting plate 13 are in contact with each other in the axial direction. It is bent slightly as it is crushed to 45. Thereby, the cover member 12a and the attachment plate 13 are easily fixed. In the motor 1a, since the length of the protrusion 52a in the axial direction is slightly longer than the thickness of the flange 4a, the protrusion 52a can be brought into contact with the upper surface 45 of the flange 4a by one press working. . Moreover, since the width in the circumferential direction of the projection 52a is wide, the circumferential direction of the region in which the projection 52a is crushed even when the jig and the central portion 521 of the projection 52a are slightly displaced during pressing of the projection 52a. Is prevented from becoming smaller. As a result, a decrease in fastening strength between the cover member 12a and the mounting plate 13 is prevented.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, A various change is possible. In the first embodiment, a cutout may be provided in the outer edge portion 13 a of the mounting plate 13, and the hook portion 42 may be engaged with the lower surface of the mounting plate 13 through the cutout. Moreover, it replaces with the hook part 42 and the site | part which protrudes in a rod shape may be provided. In this case, the cover member 12 and the mounting plate 13 are fixed by inserting the portion into the opening 51 of the step portion 5 and welding the tip to the step portion 5. The mounting plate may be formed of resin, and a hook portion may be provided on the mounting plate, and the hook portion may engage with the flange portion 4.

  In the second embodiment, instead of the flange cutout portion 44, an opening penetrating the flange portion 4a may be provided. Similarly to the first embodiment, the mounting plate 13 may be provided with a step portion, and the flange portion 4a may be provided with a recess that fits into the step portion.

  A protruding portion that protrudes downward may be provided on the flange portion 4a, and a notch portion may be provided on the outer edge portion 13a of the mounting plate 13 to perform caulking and fixing between the protruding portion and the notch portion. In this case, as in the first embodiment, the strength around the fixing portion of the mounting plate 13 may be improved by projecting the portion around the notch portion in a stepwise manner upward. It is preferable that the position of the lower end of the protrusion is positioned above the lower surface of the portion around the notch or at the same height as the lower surface.

  In the above embodiment, when the increase in the number of parts is allowed, the cover members 12 and 12a and the mounting plate 13 may be screwed. Instead of the bearing member 113 that is a ball bearing, a sleeve impregnated with lubricating oil may be used as the bearing. Preferably, two sleeves are provided at the upper part and the lower part of the inner surface of the bush 31. The bush may be formed by burring the mounting plate. In the mounting plate 13, four or more mounting holes 131 may be arranged in the circumferential direction. As long as the cylindrical part 121 of the cover members 12 and 12a is a cylinder shape which can accommodate the motor part 11, shapes other than a cylinder may be sufficient as it.

  The method of fixing the cover members 12 and 12a to the attachment plate 13 may be applied to a large motor such as a heater or a washing machine or a motor other than a home appliance.

  The configurations in the above embodiment and each modification may be combined as appropriate as long as they do not contradict each other.

  The present invention can be used for motors for various purposes.

DESCRIPTION OF SYMBOLS 1,1a Motor 4,4a Flange part 5 Step part 6 Boundary 12,12a Cover member 13 Mounting plate 21 Shaft 23 Rotor magnet 31 Bush 32 Stator 41 Recess 42 Hook part 43 Upper surface 51a (Step part) Lower surface 113 Bearing member 121 Cylindrical part 121a Lower end part of cylindrical part 131 Mounting hole 135 Peripheral part 135a Lower surface of 221 Rotor holder 222 Cylindrical part 421 Tip of hook part J1 Central axis

Claims (10)

A bearing,
A shaft that is supported by the bearing so as to be rotatable around a central axis facing in the vertical direction;
A bush for holding the bearing inside;
A stator fixed to the outer peripheral surface of the bush;
A lid-shaped substantially cylindrical rotor holder fixed to the top of the shaft;
A rotor magnet fixed to the inner peripheral surface of the cylindrical portion of the rotor holder, and positioned on the radially outer side of the stator;
A mounting plate having a plate shape extending radially outward from the lower end of the bush and used for mounting to a mounting target;
A cover member that is substantially cylindrical with a lid covering the rotor holder, and a lower end portion of a cylindrical portion is fixed to the mounting plate;
Comprising a motor. The cover member is molded of resin;
The lower end portion of the cylindrical portion includes a hook portion protruding downward,
The motor according to claim 1, wherein the hook portion engages with a lower surface of the mounting plate. The mounting plate includes a stepped portion that protrudes upward in a trapezoidal shape;
The motor according to claim 2, wherein the hook portion engages with the stepped portion.   The motor according to claim 3, wherein a position of a lower end of the hook portion is located above a lower surface of a portion around the stepped portion, or is located at the same height as the lower surface.   5. The motor according to claim 3, wherein the lower end portion of the cylindrical portion includes a concave portion that is recessed upward around the hook portion and fits with the stepped portion. The mounting plate and the cover member are made of metal,
The lower end portion of the cylindrical portion includes a flange portion that extends radially outward,
The motor according to claim 1, wherein a part of the mounting plate is bent onto an upper surface of the flange portion and contacts the upper surface.   The boundary between the tube portion of the cover member and the mounting plate exists over the entire circumference centering on the central axis, and the tube portion and the mounting plate are shaped along each other at the boundary. The motor according to any one of claims 1 to 6.   The motor according to any one of claims 1 to 7, wherein the bearing includes two bearing members inserted into an upper portion and a lower portion of the bush.   The motor according to any one of claims 1 to 8, wherein the attachment portion is three or more attachment holes arranged in a circumferential direction.   The motor according to claim 1, wherein two bearing members are fixed to the upper and lower portions of the inner peripheral surface of the bush as the bearing.

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