JP2018201264A - motor - Google Patents

Abstract

To provide a motor that is capable of further suppressing noise generation.SOLUTION: A motor 1 is provided with: a rotary shaft 10; a stator 20; a yoke 30 that is provided to the stator 20; and a magnet 40 that is supported by the yoke 30. The yoke 30 is provided with a recess 36 that is opposed to the stator 20 in a rotational axis direction, and an annular flat plate 34 that surrounds the stator 20. The recess 36 is recessed toward the stator 20. The outer peripheral part of the recess 36 is located between the inner peripheral part of the stator 20 and the outer peripheral part of the stator 20 in a radial direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a motor, and more particularly to an outer rotor type motor.

  In the outer rotor type motor, a rotor magnet is attached to an inner peripheral surface of an outer peripheral cylindrical portion of a cup-shaped yoke attached to a rotating shaft, and the rotor magnet surrounds the stator from the outer peripheral side.

  When the rotational speed of the motor is increased, vibration is generated along with this rotation, and this vibration is transmitted to the base portion and the housing holding the bearing through the bearing, so that noise is generated from the motor or the device on which the motor is mounted. It is the cause that occurs.

  Some conventional outer rotor type motors are provided with a recess in the base portion in order to reduce such noise. In the base part, the base part is formed so that the flat part other than the concave part does not have a portion that is continuous in the radial direction from the center of the base part, and the transmission of vibration is dispersed in the base part, so that it is transmitted to the housing. The vibration is attenuated to reduce noise (see, for example, Patent Document 1).

JP 2012-184748 A

  However, in such a conventional outer rotor type motor, the vibration transmitted to the housing via the base portion is attenuated, but the rotating member of the motor still generates vibration due to its rotation. Noise is generated from the motor or the device equipped with the motor. For this reason, in the conventional outer rotor type motor, the structure which can suppress the noise which generate | occur | produces by the vibration of a rotating member was calculated | required.

  This invention makes the above an example of a subject, and it aims at providing the motor which can suppress generation | occurrence | production of noise more.

  In order to achieve the above object, a motor according to the present invention includes a rotating shaft, a stator, a yoke provided on the stator, and a magnet supported by the yoke, and the yoke is arranged in the rotating shaft direction. A recess facing the stator, and an annular flat plate surrounding the stator, the recess recessed toward the stator, and the outer periphery of the recess is radially inward of the inner periphery of the stator And the outer periphery of the stator.

  In the motor according to one aspect of the present invention, the length of the recess in the radial direction is larger than the length of the recess in the rotation axis direction.

  In the motor according to one aspect of the present invention, the stator includes a plurality of plates, a resin member that covers the plurality of plates, and a coil wound around the resin member, and in the rotation axis direction, The outer peripheral part faces the coil.

  In the motor according to one aspect of the present invention, the rotary shaft is connected to the yoke on one end side of the rotary shaft, and the rotary shaft is supported by a bearing on the other end side of the rotary shaft. It is supported.

  In the motor according to one aspect of the present invention, the concave portion includes a cylindrical portion that forms an inner peripheral portion of the stator, and an annular inclined surface that surrounds the cylindrical portion. The peripheral portion is inside the outer peripheral portion of the bearing.

  In the motor according to one aspect of the present invention, in the radial direction, the length of the recess is the same as the length from the outer periphery of the recess to the outer periphery of the yoke, or from the outer periphery of the recess to the outer periphery of the yoke. It is formed larger than the length.

  In the motor according to one aspect of the present invention, the concave portion includes the flat plate portion as a first flat plate portion, and includes an annular second flat plate portion between the cylindrical portion and the inclined surface. The ratio of the length from the cylindrical portion to the outer peripheral portion of the second flat plate portion to the length from the cylindrical portion to the outer peripheral portion of the inclined surface is about 0.18 or more.

  According to the motor of the present invention, it is possible to further suppress the generation of noise.

It is sectional drawing in the cross section in alignment with the axis line for showing schematic structure of the outer rotor type motor which concerns on embodiment of this invention. It is sectional drawing in the cross section in alignment with the axis for showing the schematic structure of the yoke in the outer rotor type | mold motor which concerns on embodiment of this invention. The radial length from the cylindrical portion to the outer peripheral side connecting portion of the yoke according to the embodiment of the present invention is d1, and the radial length from the cylindrical portion to the outer peripheral cylindrical portion is d2. It is a figure for showing a relation with a frequency, and is a figure showing change of a primary natural frequency of a shake mode at the time of changing d1 / d2. In the yoke which concerns on embodiment of this invention, it is a figure for showing the change of the sound pressure at the time of changing a natural frequency.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view taken along a line x for illustrating a schematic configuration of an outer rotor type motor 1 according to an embodiment of the present invention. Hereinafter, for convenience of explanation, the reference sign A side is the outside and the reference sign B side is the inside. As will be described later, the outer side is the side where the rotating member (yoke) is attached on the rotating shaft, and the inner side is the side where the bearing is attached on the rotating shaft. In a direction orthogonal to the axis x (hereinafter, also referred to as a radial direction), the direction toward the axis x is defined as the inner peripheral side (the direction of arrow a in FIG. 1), and the direction away from the axis x is defined as the outer peripheral side ( Direction of arrow b in FIG. 1). As will be described later, with regard to the vibration mode of the yoke generated by driving the motor 1, the vibration mode based on the force in the direction of swinging the yoke is referred to as the shake mode (V1 in FIG. 1). The vibration mode based on the force is called a thrust mode (V2 in FIG. 1), and the vibration mode based on the force in the radial direction of the yoke around the rotation axis is called an annular mode (not shown). In addition, the axial direction and the longitudinal direction of the rotating shaft may be described as the rotating shaft direction.

  As shown in FIG. 1, the motor 1 includes a rotating shaft 10 that extends in the direction of the axis x, a stator 20, a yoke 30 that surrounds the stator 20, and a magnet 40 that is supported by the yoke 30. The yoke 30 includes a concave portion 36 that faces the stator 20 in the rotation axis direction, and a hollow disk-shaped annular flat plate portion 34 that surrounds the concave portion 36 on the outer peripheral side (b direction) of the concave portion 36. The recess 36 is recessed toward the stator 20 in the rotation axis direction. The outer periphery of the recess 36 is between the inner periphery of the stator 20 and the outer periphery of the stator 20 in the radial direction. Further, the length of the recess 36 in the radial direction is larger than the length of the recess 36 in the rotation axis direction.

  Specifically, as shown in FIG. 1, in the motor 1 according to the embodiment of the present invention, the rotating shaft 10 is a rod-shaped member extending in the axis x direction, and the longitudinal direction of the rotating shaft 10 is the axis x direction. It has become. The stator 20 is an annular member around the axis x. The yoke 30 is provided on the stator 20. The yoke 30 is connected to the rotating shaft 10 on the outer side (A side) as one end portion side of the rotating shaft 10 and is formed of a cup-shaped member surrounding the stator 20. The yoke 30 is made of a magnetic material such as stainless steel or iron. The magnet 40 is an annular member around the axis line x attached to the yoke 30. In addition, the motor 1 includes two bearings 50 and 60 that rotatably support the rotary shaft 10 on the inner side (B side) as the other end side of the rotary shaft 10. In each of the bearings 50 and 60, the inner ring supports the rotating shaft 10, and the outer ring is fitted in the housing 70.

  The stator 20 includes a plurality of plates 21, a resin member 22 that covers the plurality of plates, and a coil 23 wound around the resin member 22. The plurality of plates 21 are formed of a magnetic material such as an electromagnetic steel plate. Each of the plurality of plates 21 includes teeth that form magnetic pole portions. The resin member 22 has an insulating property, and electrically insulates the coil 23 and the plate 21. The stator 20 is fixed to the housing 70. The stator 20 is on the inner peripheral side (a direction side) of the magnet 40, and is disposed with a predetermined gap in the radial direction with respect to the magnet 40. The coil 23 included in the stator 20 is formed by winding a conductive wire around a resin member. A conducting wire (not shown) drawn from the coil 23 is connected to an external power source via a circuit board (not shown), and current is supplied to the coil. The conducting wire is made of a metal material such as copper.

  FIG. 2 is a cross-sectional view taken along the axis for showing a schematic configuration of the yoke 30 in the outer rotor type motor 1 according to the embodiment of the present invention. The configuration of the yoke 30 will be described with reference to FIGS. 1 and 2.

  In the yoke 30, the recess 36 includes a cylindrical portion 31 that forms the inner peripheral portion of the stator 20, an annular inclined surface 33 that surrounds the cylindrical portion 31, and an annular flat plate portion 32 between the cylindrical portion 31 and the inclined surface 33. (The second flat plate portion) and the outer peripheral portion of the concave portion 36 is on the coil 23 so as to face the coil 23 in the rotation axis direction. Here, being on the coil 23 means facing the coil 23 on the outer side in the direction of the axis x, and in the projection region of the outer coil 23 by irradiation of the coil 23 from the inner side in the direction of the axis x. This means that there is an outer peripheral portion of the recess 36. Further, in the radial direction, the inner peripheral portion of the inclined surface 33 is inside the outer peripheral portions of the bearings 50 and 60.

  In the concave portion 36 of the yoke 30, the cylindrical portion 31 is fixed to the rotating shaft 10 by press fitting or the like. The cylindrical portion 31 has a cylindrical shape or a substantially cylindrical shape (outer shape) extending in the direction of the axis x. The flat plate portion 32 has a disk-like shape (outer shape) extending radially outward from the inner edge of the cylindrical portion 31. The inclined surface 33 has an annular shape (outer shape) that extends outward from the edge on the outer peripheral side (b direction) of the flat plate portion 32. The inclined surface 33 extends obliquely toward the inner peripheral edge of the flat plate portion 34 (first flat plate portion). In the rotation axis direction, the outer edge of the inclined surface 33 is on the inner side (B side) with respect to the inner peripheral edge of the flat plate portion 34.

  The annular flat plate portion 34 of the yoke 30 has a disk-like shape (outer shape) extending in the radial direction from the outer peripheral edge of the inclined surface 33 toward the outer peripheral side. Further, the yoke 30 includes a cylindrical portion 35, and the cylindrical portion 35 includes a cylindrical shape or a substantially cylindrical shape (outer shape) extending inward in the axis x direction from the outer peripheral edge of the annular flat plate portion 34. ing. The cylindrical portion 31 described above is an inner peripheral cylindrical portion of the yoke 30, and the cylindrical portion 35 is an outer peripheral cylindrical portion of the yoke 30.

  The annular flat plate portion 34 includes an outer surface 34a facing outward. The cylinder part 31 of the recessed part 36 is provided with the outer side end 31a which is an outer end. The outer end 31a is in the recess 36, and is on the inner side in the axis x direction than the outer surface 34a. The outer end 31a may be flush with the outer surface 34a in the axis x direction, or may be located outside the outer surface 34a.

  The flat plate portion 32 has an inner peripheral portion 32a that is an annular portion connected to the cylindrical portion 31, and an outer peripheral portion 32b that is connected to the inner peripheral portion 32a on the outer peripheral side. The outer peripheral portion 32b protrudes to the inner side (outer side) of the recess 36 in the axis x direction than the inner peripheral portion 32a, and an annular step 32c is formed between the inner peripheral portion 32a and the outer peripheral portion 32b. . The flat plate portion 32 does not have the stepped portion 32c, and may be formed as a flat plate portion having the same shape.

  The inclined surface 33 is formed so as to increase in diameter toward the outside in the axis x direction, and has, for example, a conical cylindrical shape. The yoke 30 includes an outer peripheral side connection portion 36 a that is a connection portion between the inclined surface 33 and the annular flat plate portion 34, an inner peripheral side connection portion 36 b that is a connection portion between the inclined surface 33 and the flat plate portion 32, and the cylindrical portion 31. And an inner cylinder connecting portion 36c which is a connecting portion between the flat plate portion 32 and the flat plate portion 32.

  The annular flat plate portion 34 is formed thicker than the thickness of the cylindrical portion 31, the flat plate portion 32, and the inclined surface 33, and the cylindrical portion 35 has the same or substantially the same thickness as the annular flat plate portion 34. ing. The annular flat plate portion 34 may be formed with the same or substantially the same thickness as the cylindrical portion 31, the flat plate portion 32, and the inclined surface 33.

  In a state where the yoke 30 is attached to the rotary shaft 10, the concave portion 36 is disposed to face the stator 20 in the axis line x direction. Specifically, in the recess 36, a part of the outer peripheral side of the inclined surface 33 is formed so as to cover a part of the stator 20 from the outside in the direction of the axis x. An outer peripheral side connection portion 36 a as an outer peripheral side portion (outer peripheral portion) of the recess 36 is connected to an inner peripheral side portion (inner peripheral portion) of the flat plate portion 34. Further, the outer peripheral side connecting portion 36 a is located between the inner peripheral portion 20 a that is a portion on the inner peripheral side of the stator 20 and the outer peripheral portion 20 b that is a portion on the outer peripheral side of the stator 20 in the radial direction.

  In the recess 36, the length (d 1) in the radial direction from the inner peripheral surface 31 b facing the rotation axis of the cylindrical portion 31 (inner peripheral cylindrical portion) to the outer peripheral portion (outer peripheral side connecting portion 36 a) is It is the same as the length (d2-d1) in the radial direction from the outer peripheral portion (outer peripheral side connecting portion 36a) to the cylindrical portion 35 (specifically, the inner peripheral surface 35a), or this length (d2-d1) It is formed so as to be larger. The length d1 may be smaller than the length (d2-d1). For example, d1 / (d2-d1) is 0.25 or more. Preferably, d1 / d2 is about 0.4 or more and about 0.6 or less. The length d2 is the length in the radial direction from the inner peripheral surface 31b of the cylindrical portion (inner peripheral cylindrical portion) 31 to the inner peripheral surface 35a of the cylindrical portion (outer peripheral cylindrical portion) 35, and the inner peripheral surface 35a is The surface facing the outer peripheral surface of the magnet 40.

  Further, in a state where the yoke 30 is attached to the rotary shaft 10, in the radial direction, the inner peripheral side connection portion 36b as the inner peripheral portion of the inclined surface 33 is a portion on the outer peripheral side of the bearing 50 and the bearing 60 (the outer peripheral portion 50a). , 60a) on the inner peripheral side. Specifically, the ratio of the length (d0) in the radial direction from the inner peripheral surface 31b of the cylindrical portion 31 to the inner peripheral side connection portion 36b of the concave portion 36 with respect to the length d1 is about 0.18 or more. It is formed as follows.

  In the motor 1 having the above-described configuration, when a current supplied from an external power source through a circuit board is supplied to the coil 23 through a conductive wire, a magnetic flux flow is generated in the plate 21. The rotary shaft 10 rotates by the interaction with the generated magnetic flux flow, and the yoke 30 rotates.

  FIG. 3 shows changes in the primary natural frequency of the shake mode when d1 / d2 is changed in the yoke 30 according to the embodiment of the present invention. In the relationship shown in FIG. 3, the value of d1 / d2 is changed by fixing the value of d2 and using the value of d1 as a parameter. As shown in FIG. 3, when the value of d1 / d2 is increased, that is, when the radial length d1 of the recess 36 is made larger than the radial length d2 of the yoke 30, 1 in the deflection mode of the yoke 30 is obtained. It can be seen that the second natural frequency can be shifted to the high frequency side. d1 / d2 is a parameter of the rigidity of the yoke 30 with respect to the force that causes the swing mode (see V1 in FIG. 1) of the yoke 30, and is a parameter of the moment of inertia with the outer peripheral side connection portion 36a as the center. That is, when d1 / d2 is increased in the yoke 30, the moment of inertia around the outer peripheral side connection portion 36a is reduced, and distortion or vibration in the outer peripheral side connection portion 36a can be reduced.

  FIG. 4 shows a change in sound pressure in the yoke 30 according to the embodiment of the present invention when the primary natural frequency in the vibration mode of the yoke 30 is changed using d1 / d2 as a parameter. As shown in FIG. 4, when the primary natural frequency in the vibration mode of the yoke 30 is shifted to the high frequency side using d1 / d2 as a parameter, the pressure of sound generated from the yoke 30 (hereinafter also referred to as sound pressure). ) Can be reduced.

  Thus, in the motor 1 according to the embodiment of the present invention, the outer peripheral side connecting portion 36a of the recess 36 is between the inner peripheral portion 20a and the outer peripheral portion 20b of the stator 20 in the radial direction, and d1 / d2 The value of can be increased. For this reason, the primary natural frequency in the vibration mode of the yoke 30 can be shifted to the high frequency side, the sound pressure emitted from the yoke 30 can be reduced, and the primary natural frequency in the vibration mode of the yoke 30 can be reduced. It is possible to remove the sound generated by the rotation of the sound from the audible range of the person and make it difficult for the person to hear.

  Furthermore, it has been found that by increasing the value of d1 / d2, the natural frequency in other vibration modes of the yoke 30 can also be shifted to the high frequency side. The other vibration modes include, for example, a secondary natural frequency in the shake mode, a primary natural frequency in the thrust mode, and a secondary natural frequency in the annular mode. For this reason, in the motor 1 according to the embodiment of the present invention, it is possible to make it difficult to hear the sound generated from the yoke 30 even when the yoke 30 rotates at the natural frequency of another vibration mode.

  Further, in the motor 1 according to the embodiment of the present invention, the value of d0 is set as small as possible, and the inner peripheral side connection portion 36b of the inclined surface 33 is more than the outer peripheral portions 50a and 60a of the bearings 50 and 60 in the radial direction. Is also on the inner circumference side. For this reason, it becomes possible to set the rigidity of the flat plate part 32 with respect to the force that causes the vibration mode (see V1 in FIG. 1) of the yoke 30 to be high, and the vibration (amplitude) of the flat plate part 32 can be reduced. Therefore, the sound pressure emitted from the yoke 30 can be reduced, and the sound produced when the yoke 30 rotates at the primary natural frequency in the shake mode can be made difficult to hear.

  Thus, according to the motor 1 which concerns on embodiment of this invention, generation | occurrence | production of noise can be suppressed more.

  Further, in the motor 1 according to the embodiment of the present invention, the outer peripheral side connection portion 36a is located above (outside) the coil 23 of the stator 20 in the axis line x direction. As a result, the stator 20 can be disposed in the yoke 30 while increasing the value of d1 / d2.

  Further, in the motor 1 according to the embodiment of the present invention, the yoke 30 has the step portion 32 c in the flat plate portion 32. For this reason, the rigidity of the flat plate part 32 in the rotation axis direction can be increased.

  In the motor 1 according to the embodiment of the present invention, the annular flat plate portion 34 is formed thicker than the thickness of the cylindrical portion 31, the flat plate portion 32, and the inclined surface 33. For this reason, the rigidity of the flat plate portion 34 can be increased.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the motor 1 which concerns on the said embodiment of this invention, All the aspects included in the concept and claim of this invention are included. Including. In addition, the configurations may be appropriately combined as appropriate so as to achieve at least part of the problems and effects described above. For example, the shape, material, arrangement, size, and the like of each component in the above embodiment can be appropriately changed depending on the specific usage mode of the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Motor, 10 ... Rotating shaft, 20 ... Stator, 20a ... Inner peripheral part, 20b ... Outer peripheral part, 21 ... Plate, 22 ... Resin member, 23 ... Coil, 30 ... Yoke, 31 ... Cylindrical part (inner peripheral cylindrical part) ), 31a ... outer end, 31b ... inner peripheral surface, 32 ... flat plate portion (second flat plate portion), 32a ... inner peripheral portion, 32b ... outer peripheral portion, 32c ... stepped portion, 33 ... inclined surface, 34 ... flat plate portion ( First flat plate part), 34a ... outer side surface, 35 ... cylinder part (outer peripheral cylinder part), 35a ... inner peripheral surface, 36 ... recessed part, 36a ... outer peripheral side connection part, 36b ... inner peripheral side connection part, 36c ... inner cylinder Connection part, 40 ... magnet, 50, 60 ... bearing, 70 ... housing, A ... outside, B ... inside, a ... inner circumference side, b ... outer circumference side, x ... axis.

Claims (7)

A rotation axis;
A stator,
A yoke provided on the stator;
A magnet supported by the yoke,
The yoke includes a recess facing the stator in the rotation axis direction, and an annular flat plate portion surrounding the stator,
The recess is recessed toward the stator;
The outer periphery of the recess is a motor between the inner periphery of the stator and the outer periphery of the stator in the radial direction.   The motor according to claim 1, wherein a length of the concave portion in the radial direction is larger than a length of the concave portion in the rotation axis direction. The stator includes a plurality of plates, a resin member that covers the plurality of plates, and a coil wound around the resin member,
The motor according to claim 1, wherein an outer peripheral portion of the concave portion faces the coil in a rotation axis direction. On one end side of the rotating shaft, the rotating shaft is connected to the yoke,
The motor according to any one of claims 1 to 3, wherein the rotary shaft is supported by a bearing on the other end side of the rotary shaft. The concave portion includes a cylindrical portion that forms an inner peripheral portion of the stator, and an annular inclined surface that surrounds the cylindrical portion,
5. The motor according to claim 4, wherein an inner peripheral portion of the inclined surface is on an inner side than an outer peripheral portion of the bearing in a radial direction.   In the radial direction, the length of the recess is the same as the length from the outer periphery of the recess to the outer periphery of the yoke, or greater than the length from the outer periphery of the recess to the outer periphery of the yoke. The motor according to any one of claims 1 to 5. The concave portion includes an annular second flat plate portion between the cylindrical portion and the inclined surface, with the flat plate portion serving as a first flat plate portion,
The ratio of the length from the cylindrical portion to the outer peripheral portion of the second flat plate portion with respect to the length from the cylindrical portion to the outer peripheral portion of the inclined surface in the radial direction is about 0.18 or more. 5. The motor according to 5.

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