JP2018038260A - motor - Google Patents

Abstract

A motor capable of preventing the displacement of a bearing is provided. A motor is an outer rotor type motor including a stator including a coil and a rotor including a magnet facing the coil on the outer diameter side of the coil. The rotor 10 includes a shaft 13 that rotates about a rotation axis R. The stator 20 includes a housing portion 23a that houses the lower end portion 13a of the shaft 13, and an annular retaining washer 41 that protrudes from the inner peripheral surface of the housing portion 23a toward the inner diameter side. The motor 100 further includes a bearing 31 that is fixed to the inner peripheral surface of the housing portion 23a and supports the shaft 13 rotatably. The retaining washer 41 is provided at a position farther from the lower end portion 13a than the bearing 31 in the rotation axis R direction. [Selection] Figure 1

Description

  The present invention relates to a motor, and more particularly to an outer rotor type motor including a stator including a coil and a rotor including a magnet facing the coil on the outer diameter side of the coil.

  In general, an outer rotor type brushless motor includes a bearing housing, an annular stator core fixed to the outer peripheral surface of the bearing housing, and a rotor disposed so as to surround the stator core. The stator core includes a stator yoke formed with a plurality of pole teeth, and a coil is wound around each of the plurality of pole teeth. The rotor includes a magnet in which magnetic poles having different polarities are alternately arranged along the periphery, and a shaft on which the magnet is fixed. The shaft is rotatably supported by a bearing fixed to the inner peripheral surface of the bearing housing.

  Patent Document 1 below discloses a bearing support structure that prevents a bearing fixed to the inner peripheral surface of a bearing housing from being displaced. The bearing support structure of the following Patent Document 1 includes a housing having an opening and a receiving space, a bearing that supports a part of the rotating shaft, and a bearing installed in the receiving space, and a second restriction that limits the axial movement of the bearing. And an assembly. The second restriction assembly includes an elastic body fitted into the outer wall of the rotating shaft, and a cover that covers the opening and stops the elastic material. The cover is fixed to the rotating shaft.

JP 2008-185209 A

  The conventional motor has a problem that when the shaft rotates, the force with which the bearing housing holds the bearing is weakened due to the expansion of the bearing housing, and the bearing fixed to the bearing housing is displaced (raised) in the axial direction. When the bearing is an oil-impregnated bearing, the coefficient of static friction between the bearing and the bearing housing is lowered by the oil, and the force with which the bearing housing holds the bearing is weakened. As a result, when the bearing is an oil-impregnated bearing, the bearing is easily displaced in the axial direction when the shaft rotates. Further, the bearing is difficult to adhere to the bearing housing due to the oil contained in the bearing itself.

  In the technique of Patent Document 1, a second limiting assembly that limits the axial movement of the bearing is fixed to the shaft. Since the shaft could move in the axial direction, the effect of the second limiting assembly limiting the axial movement of the bearing was not sufficient.

  The present invention is for solving the above-described problems, and an object of the present invention is to provide a motor capable of preventing a bearing from being displaced.

A motor according to one aspect of the present invention has a rotor including a stator including a coil, a magnet facing the coil on the outer diameter side of the coil, and a shaft, and an end in the longitudinal direction of the shaft. A bearing housing, a bearing provided inside the bearing housing, and a retaining portion fixed to an inner peripheral surface of the bearing housing, the bearing supporting the shaft, and an end of the bearing housing The entire portion protrudes toward the shaft in the radial direction, and the retaining portion is disposed between the end of the bearing housing and the bearing in the longitudinal direction of the shaft. In the longitudinal direction, the end of the bearing housing contacts the retaining portion, and in the longitudinal direction of the shaft, the retaining portion contacts the bearing. In the radial direction, the inner peripheral surface of the end portion of the inner peripheral surface and the bearing housing of the retaining portion is spaced from said shaft, said bearing is a rolling bearing, a motor.
Further, a motor according to another aspect of the present invention includes a rotor including a stator including a coil, a magnet facing the coil on the outer diameter side of the coil, and a shaft, and an end portion in a longitudinal direction of the shaft. A bearing housing, a bearing provided inside the bearing housing, and a retaining portion fixed to an inner peripheral surface of the bearing housing, the bearing supporting the shaft, and the bearing housing The entire end of the projection protrudes toward the shaft in the radial direction, and the retaining portion is disposed between the end of the bearing housing and the bearing in the longitudinal direction of the shaft, In the longitudinal direction of the shaft, the end portion of the bearing housing is in contact with the retaining portion, and in a position facing the bearing in the longitudinal direction of the shaft. That, in contact with the retaining portion of the surface across said bearing in the radial direction, the inner peripheral surface of the inner peripheral surface and an end portion of the bearing housing of said retaining portion is separated from said shaft, a motor.
Preferably, in the motor, a surface of the retaining portion that is at a position facing the bearing in the longitudinal direction of the shaft is flat.
Preferably, in the motor, the bearing is fixed by press-fitting inside the bearing housing.
Preferably, in the motor, the bearing is fixed to the inner peripheral surface of the bearing housing by press fitting.
Preferably, in the motor, the retaining portion is a separate body from the bearing housing.
Preferably, in the motor, the housing portion included in the bearing housing and the retaining portion have the same material.

  ADVANTAGE OF THE INVENTION According to this invention, the motor which can prevent the shift | offset | difference of a bearing can be provided.

It is sectional drawing which shows the structure of the motor in one embodiment of this invention. FIG. 2 is an enlarged view of the vicinity of a housing portion 23a in FIG. 4 is a perspective view showing an example of a configuration of a retaining washer 41. FIG. It is a perspective view which shows the other example of a structure of the retaining washer 41. FIG. It is sectional drawing which shows the structure of the motor in the 1st modification of this invention. FIG. 6 is an enlarged view of the vicinity of the accommodating portion 23a in FIG. It is sectional drawing which shows the structure of the motor in the 2nd modification of this invention. FIG. 8 is an enlarged view of the vicinity of a housing portion 23a in FIG.

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

  FIG. 1 is a cross-sectional view showing a configuration of a motor according to an embodiment of the present invention.

  Referring to FIG. 1, motor 100 in the present embodiment is an outer rotor type including stator 20 including coil 22 and rotor 10 including magnet 12 facing coil 22 on the outer diameter side of coil 22. It is a brushless motor. The rotor 10 is rotatable with respect to the stator 20.

  The rotor 10 includes a rotor yoke 11, a magnet 12, a shaft 13, and a washer 14.

  The rotor yoke 11 prevents leakage of a magnetic field from the inside of the rotor yoke 11, and is made of, for example, a magnetic material. The rotor yoke 11 includes a rotor yoke ceiling portion 11a, a rotor yoke side wall portion 11b, and a rotor yoke fixing portion 11c. The rotor yoke ceiling portion 11a extends, for example, in a direction perpendicular to the rotation axis R of the shaft 13 (lateral direction in FIG. 1). The rotor yoke ceiling portion 11a has a circular shape when seen in a plan view. The rotor yoke side wall portion 11b extends downward in FIG. 1 from the outer diameter side end portion of the rotor yoke ceiling portion 11a. The rotor yoke side wall part 11b has a cylindrical shape. The rotor yoke fixing portion 11c extends downward from the inner diameter side end portion of the rotor yoke ceiling portion 11a in FIG. The rotor yoke fixing part 11c has a cylindrical shape. A hole 61 through which the shaft 13 is passed is provided on the inner diameter side of the rotor yoke fixing portion 11 c, and the rotor yoke 11 is fixed to the shaft 13 in the hole 61.

  The magnet 12 is attached to the inner peripheral surface of the rotor yoke side wall 11b. The magnet 12 has an annular shape, and regions magnetized in the N pole and regions magnetized in the S pole are alternately provided at regular intervals along the circumferential direction. The magnet 12 is attached to the rotor yoke 11 so as to face the stator 20. The magnet 12 is fixed to the shaft 13 via the rotor yoke 11.

  The shaft 13 extends in the direction of the rotation axis R so as to penetrate the central portion of the rotor yoke 11. The shaft 13 and the rotor yoke 11 rotate integrally around the rotation axis R.

  The washer 14 is fixed to the outer peripheral surface of the shaft 13. The lower surface of the washer 14 is in contact with the upper surface of the rotor yoke ceiling portion 11a. The washer 14 restricts the upward movement of the rotor yoke 11 in FIG. 1 (the removal of the rotor yoke 11).

  The stator 20 includes a stator core 21, a coil 22, a bearing housing 23, an electronic substrate 24, and a thrust plate 25.

  The stator core 21 is made of a laminate of silicon steel plates or the like, and is fixed to the housing portion 23 a of the bearing housing 23. Stator core 21 includes a plurality of teeth 21a formed to extend radially from the inner diameter side toward the outer diameter side.

  The coil 22 is wound around each of the plurality of tooth portions 21a. The stator core 21 and the coil 22 are insulated by an insulator 22a made of an insulator.

  The bearing housing 23 is formed by die casting, for example, and includes a housing portion 23a and an outer edge portion 23b. The accommodating portion 23a constitutes a space SP, and the lower end portion 13a of the shaft 13 and the vicinity thereof are accommodated in the space SP. The accommodating portion 23a extends in the direction of the rotation axis R so as to surround a side surface near the lower end portion 13a of the shaft 13. Moreover, the accommodating part 23a is extended in the horizontal direction in FIG. 1 in the center part of a motor so that the lower end part 13a of the shaft 13 may be covered. A stator core 21 is fixed to the outer peripheral surface of the accommodating portion 23a. The outer edge portion 23b extends in the outer diameter direction from the lower end portion of the outer peripheral surface of the accommodating portion 23a.

  The electronic substrate 24 is fixed on the outer edge portion 23b. Conductive wires are formed of copper foil or the like on the electronic substrate 24, and the electronic component 24a is attached by soldering.

  The thrust plate 25 is provided on the bottom surface of the space SP formed by the accommodating portion 23a. The thrust plate 25 is in contact with the lower end portion 13 a of the shaft 13 and receives the thrust load of the shaft 13.

  The motor 100 further includes a motor case 30 and bearings (metals) 31 and 32. The stator 20 further includes a retaining washer (metal presser) 41 (an example of a retaining portion).

  The motor case 30 includes a motor case ceiling part 30a, a motor case side wall part 30b, and a motor case fixing part 30c. The motor case ceiling portion 30a extends, for example, in a direction perpendicular to the rotation axis R of the shaft 13 (lateral direction in FIG. 1). The motor case ceiling 30a has a circular shape when seen in a plan view. The motor case side wall 30b extends downward in FIG. 1 from the outer diameter side end of the motor case ceiling 30a. The motor case side wall 30b has a cylindrical shape. The motor case fixing portion 30c extends upward in FIG. 1 from the inner diameter side end portion of the motor case ceiling portion 30a. The motor case fixing part 30c has a cylindrical shape. A hole 62 through which the shaft 13 is passed is provided on the inner diameter side of the motor case fixing portion 30c.

  The bearing 31 is fixed to the inner peripheral surface of the accommodating portion 23a. The bearing 31 supports the shaft 13 rotatably with respect to the bearing housing 23. The bearing 32 is fixed to the inner peripheral surface of the motor case fixing portion 30c. The bearing 32 rotatably supports the shaft 13 with respect to the motor case 30 in the hole 62. There is a minute gap (for example, several μm) between the shaft 13 and each of the bearings 31 and 32. Each of the bearings 31 and 32 may be a rolling bearing or a sliding bearing, but is preferably an oil-impregnated bearing from the viewpoint of simplifying the configuration. An oil-impregnated bearing is a bearing in which oil is infiltrated into a main body made of a porous material (for example, metal), and is a kind of a sliding bearing.

  The retaining washer 41 is annular and protrudes in the inner diameter direction (shaft 13 direction) from the inner peripheral surface of the housing portion 23a. The retaining washer 41 is provided at a position farther from the lower end portion 13a of the shaft 13 than the bearing 31 in the direction of the rotation axis R (that is, a position above the bearing 31 in FIG. 1).

  FIG. 2 is an enlarged view of the vicinity of the accommodating portion 23a in FIG.

  Referring to FIG. 2, the accommodating portion 23 a includes a first portion 71 that accommodates the lower end portion 13 a of the shaft 13 and the vicinity thereof, and a second portion that is adjacent to the first portion 71 on the upper side of the first portion 71. Part 72. The first portion 71 has a diameter D1. The second portion 72 has a diameter D2. The diameter D2 is larger than the diameter D1.

  The bearing 31 is in contact with a stepped portion 73 formed at the boundary between the first portion 71 and the second portion 72. The retaining washer 41 is a separate body from the housing portion 23a. Each of the bearing 31 and the retaining washer 41 is fixed to the inner peripheral surface of the second portion 72 of the accommodating portion 23a by press-fitting. The lower surface of the retaining washer 41 is in contact with the upper surface of the bearing 31. The retaining washer 41 is disposed at a distance from the shaft 13 in the radial direction. When each of the bearing 31 and the retaining washer 41 is press-fit, the outer peripheral surface of each of the bearing 31 and the retaining washer 41 and the upper surface or the lower surface (previously in the housing portion 23a) for the purpose of smooth press-fitting. The corner of the boundary with the surface to be inserted is preferably chamfered.

  FIG. 3 is a perspective view showing an example of the configuration of the retaining washer 41. FIG. 4 is a perspective view showing another example of the configuration of the retaining washer 41.

  Referring to FIGS. 3 and 4, retaining cap 41 may be a flat washer as shown in FIG. 3 or a toothed washer as shown in FIG. 4. The flat washer is composed of a single cylindrical surface on the entire outer periphery. The toothed washer is provided with a plurality of protrusions 41a at equal angles on its outer peripheral surface. When the retaining washer 41 is a toothed washer 41, pressure input to the bearing housing 23 can be reduced, and the effect of retaining the bearing 31 can be increased.

  The retaining washer 41 is preferably made of the same material as the bearing housing 23 (base material). Thereby, when the bearing housing 23 is thermally expanded by the heat generated by the rotation of the motor 100, it is possible to prevent the retaining washer 41 from being loosened. In addition, the retaining washer 41 preferably has a flat bottom surface (having a normal line in the direction of the rotation axis R) in view of uniformly pressing the bearing 31.

  Note that the fixing method of the retaining washer 41 to the bearing housing 23 may be a method other than press fitting such as adhesion.

  [Modification]

  FIG. 5 is a cross-sectional view showing the configuration of the motor in the first modification of the present invention. FIG. 6 is an enlarged view of the vicinity of the accommodating portion 23a in FIG.

  With reference to FIGS. 5 and 6, the retaining washer 41 may be integrated with the bearing housing 23 in addition to the case where it is separate from the bearing housing 23 as described above. In this modification, the retaining washer 41 is replaced with a protrusion 42 protruding in the inner diameter direction from the inner peripheral surface of the housing portion 23a. The bearing housing 23 has a two-body structure divided into two in the direction of the rotation axis R. Here, in the accommodating portion 23a, the first portion 71 and the second portion 72 are configured separately. When the motor 100 is manufactured, the bearing 31 is press-fitted into the second portion 72 from the lower side in FIG. 6 so as to be in contact with the lower surface of the protrusion 42 without the first portion 71. Thereafter, the first portion 71 is brought into contact with the lower surfaces of the bearing 31 and the second portion 72 from the lower side in FIG. 6, and is fitted to the second portion 72 and the fitting portion 74. Thereby, the structure by which the bearing 31 is arrange | positioned in the accommodating part 23a is realizable.

  FIG. 7 is a cross-sectional view showing the configuration of the motor in the second modification of the present invention. FIG. 8 is an enlarged view of the vicinity of the accommodating portion 23a in FIG.

  With reference to FIGS. 7 and 8, the present modification is obtained by applying the configuration of the accommodating portion 23a of the first modification to the motor shown in FIG. That is, the bearing housing 23 has a two-body structure divided into two in the direction of the rotation axis R. The retaining washer 41 is separate from the housing portion 23a and is fixed to the inner peripheral surface of the second portion 72 of the housing portion 23a by press-fitting. A washer stopper 75 projects from the inner peripheral surface of the storage portion 23 a at the top of the retaining washer 71. The washer stopper 75 prevents the retaining washer 41 from moving upward. When the motor 100 is manufactured, each of the bearing 31 and the retaining washer 41 is press-fitted into the second portion 72 from the lower side in FIG. 8 without the first portion 71. The upper surface of the retaining washer 41 contacts the lower surface of the washer stopper 75. Thereafter, the first portion 71 is brought into contact with the lower surfaces of the bearing 31 and the second portion 72 from the lower side in FIG. 8 and is fitted to the second portion 72 and the fitting portion 74. Thereby, the structure by which the bearing 31 is arrange | positioned in the accommodating part 23a is realizable.

  Since the configuration other than the above in each of the first and second modifications is the same as the configuration of the motor shown in FIG. 1, the same reference numerals are given to the same members, and the description thereof will not be repeated.

  [Effect of the embodiment]

  According to the present embodiment, the retaining washer 41 or the protrusion 42 serves as a bearing retainer, and applies a force in the direction of the lower end portion 13a (downward in FIG. 1) to the bearing 31. Thereby, it is possible to prevent the bearing 31 from shifting upward in FIG. 1 (lifting in the direction of the rotation axis R) when the shaft 13 rotates, and to prevent the bearing 31 from falling off the housing portion 23a. it can.

  Further, by making the retaining washer 41 separate from the bearing housing 23, the retaining washer 41 does not become an obstacle when the bearing 31 is press-fitted into the housing portion 23a. Furthermore, by fixing the retaining washer 41 to the inner peripheral surface of the storage portion 23a by press-fitting, the bearing 31 and the retaining washer 41 can be fixed to the inner peripheral surface of the storage portion 23a by a simple method.

  [Others]

  The motor may be a brush motor such as a DC (Direct-current) motor, or may be a brushless motor such as a stepping motor.

  The above-described embodiment is to be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 10 Rotor 11 Rotor yoke 11a Rotor yoke ceiling part 11b Rotor yoke side wall part 11c Rotor yoke fixed part 12 Magnet 13 Shaft 13a Shaft lower end part 14 Washer 20 Stator 21 Stator core 21a Teeth part 22 Coil 22a Insulator 23 Bearing housing 23b Bearing housing housing part 23b Outer edge portion 24 Electronic board 24a Electronic component 25 Thrust plate 30 Motor case 30a Motor case ceiling portion 30b Motor case side wall portion 30c Motor case fixing portion 31, 32 Bearing 41 Retaining washer 41a Retaining washer protrusion 42 Protrusion 61, 62 Hole 71 First portion of housing portion 72 Second portion of housing portion 73 Step portion of housing portion 74 Fitting portion 75 Washer stopper 100 Mo D1, D2 space for accommodating the lower portion of the diameter R rotating shaft SP shaft

A motor according to an aspect of the present invention includes a rotor having a shaft, a bearing housing having an end in the longitudinal direction of the shaft, and a bearing provided inside the bearing housing. A protrusion protruding toward the shaft is provided on the inner peripheral surface, the bearing supports the shaft, and the protrusion is formed between the end of the bearing housing and the bearing in the longitudinal direction of the shaft. In the longitudinal direction of the shaft, the surface of the protrusion that extends toward the bearing contacts the bearing, and in the radial direction, the inner peripheral surface of the protrusion and the end of the bearing housing. The inner peripheral surface of the motor is separated from the shaft, and the bearing is a motor that is a rolling bearing.
A motor according to another aspect of the present invention includes a rotor having a shaft, a bearing housing having an end in the longitudinal direction of the shaft, a bearing provided inside the bearing housing, and an inner peripheral surface of the bearing housing. Has a protrusion protruding toward the shaft, the bearing supports the shaft, and the protrusion is disposed between the end of the bearing housing and the bearing in the longitudinal direction of the shaft. And the end of the protrusion extending toward the bearing in the longitudinal direction of the shaft is in contact with the bearing, and is in a position facing the bearing in the longitudinal direction of the shaft. The entire end portion contacts the bearing, and in the radial direction, the inner peripheral surface of the protrusion and the inner peripheral surface of the end portion of the bearing housing are separated from the shaft. It is a motor.
Preferably, in the motor, a part of the protrusion projects toward the bearing in the longitudinal direction of the shaft.
Preferably, in the motor, the protrusion is separate from the bearing housing.
A motor according to another aspect of the present invention includes a rotor having a shaft , a bearing housing having an end in the longitudinal direction of the shaft, a bearing provided inside the bearing housing, and an inner peripheral surface of the bearing housing. And the bearing supports the shaft, and the entire end portion of the bearing housing protrudes toward the shaft in the radial direction. In the longitudinal direction of the shaft, the bearing housing is disposed between the end of the bearing housing and the bearing. In the longitudinal direction of the shaft, the end of the bearing housing contacts the retaining portion, and the longitudinal direction of the shaft The retaining portion contacts the bearing, and in the radial direction, the inner peripheral surface of the retaining portion and the inner peripheral surface of the end portion of the bearing housing are Is away from the shift, the bearing is a rolling bearing, a motor.
A motor according to another aspect of the present invention includes a rotor having a shaft, in the longitudinal direction of the shaft, a bearing housing having an end, a bearing provided inside the bearing housing, of the bearing housing A retaining portion fixed to a peripheral surface, and the bearing supports the shaft, and an entire end portion of the bearing housing protrudes toward the shaft in a radial direction, and the retaining portion is The shaft is disposed between the end of the bearing housing and the bearing in the longitudinal direction of the shaft, and the end of the bearing housing is in contact with the retaining portion in the longitudinal direction of the shaft. The entire surface of the retaining portion at a position facing the bearing in the longitudinal direction is in contact with the bearing, and in the radial direction, the inner peripheral surface of the retaining portion and The inner peripheral surface of the end portion of the serial bearing housing is separated from said shaft, a motor.
Preferably, in the motor, a surface of the retaining portion that is at a position facing the bearing in the longitudinal direction of the shaft is flat.
Preferably, in the motor, the bearing is fixed by press-fitting inside the bearing housing.
Preferably, in the motor, the bearing is fixed to the inner peripheral surface of the bearing housing by press fitting.
Preferably, in the motor, the retaining portion is a separate body from the bearing housing.
Preferably, in the motor, the housing portion included in the bearing housing and the retaining portion have the same material.

Claims (7)

A rotor including a stator including a coil, a magnet facing the coil on the outer diameter side of the coil, and a shaft;
A bearing housing having an end in the longitudinal direction of the shaft;
A bearing provided inside the bearing housing;
A retaining portion fixed to the inner peripheral surface of the bearing housing;
With
The bearing supports the shaft;
The entire end of the bearing housing projects in the radial direction toward the shaft,
The retaining portion is disposed between the end of the bearing housing and the bearing in the longitudinal direction of the shaft,
In the longitudinal direction of the shaft, the end of the bearing housing contacts the retaining portion,
In the longitudinal direction of the shaft, the retaining portion contacts the bearing,
In the radial direction, the inner peripheral surface of the retaining portion and the inner peripheral surface of the end portion of the bearing housing are separated from the shaft,
The motor is a rolling bearing. A rotor including a stator including a coil, a magnet facing the coil on the outer diameter side of the coil, and a shaft;
A bearing housing having an end in the longitudinal direction of the shaft;
A bearing provided inside the bearing housing;
A retaining portion fixed to the inner peripheral surface of the bearing housing;
With
The bearing supports the shaft;
The entire end of the bearing housing projects in the radial direction toward the shaft,
The retaining portion is disposed between the end of the bearing housing and the bearing in the longitudinal direction of the shaft,
In the longitudinal direction of the shaft, the end of the bearing housing contacts the retaining portion,
The entire surface of the retaining portion at a position facing the bearing in the longitudinal direction of the shaft is in contact with the bearing;
In the radial direction, the inner peripheral surface of the retaining portion and the inner peripheral surface of the end portion of the bearing housing are separated from the shaft.   The motor according to claim 1, wherein a surface of the retaining portion located at a position facing the bearing in the longitudinal direction of the shaft is flat.   The motor according to claim 1, wherein the bearing is fixed by press fitting inside the bearing housing.   The motor according to claim 1, wherein the bearing is fixed to the inner peripheral surface of the bearing housing by press-fitting.   The motor according to claim 1, wherein the retaining portion is separate from the bearing housing.   The motor according to claim 1, wherein the housing portion included in the bearing housing and the retaining portion have the same material.

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