JP2017225318A - motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor that has a simple configuration and rotates highly accurately.SOLUTION: A motor comprises: a motor housing 1; a rotor 3 including a shaft 31; and a first bearing 41 and second bearing 42 supporting the shaft 31 such that the shaft is rotatable. The motor housing 1 has: a cylindrical external wall part 11 extending axially; a flange part 13 extending radially inside from an outside edge part of the external wall part; and a cylindrical internal wall part 12 extending axially from an inside edge part of the flange part 13. A cylindrical bearing housing 5 extending axially is fixed to an internal wall part. Inner wheels 412, 422 of the first bearing 41 and the second bearing 42, respectively, are fixed to the shaft 31. An outer ring 411 of the first bearing 41 is fixed to an internal surface of the internal wall part 12, and an outer ring 421 of the second bearing 42 is fixed to an internal surface of the bearing housing 5.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a motor.

  A conventional inner rotor type brushless motor is described in Patent Document 1, for example. In Patent Document 1, an inner rotor brushless motor includes a substantially bottomed cylindrical motor housing, a stator disposed on the inner peripheral surface of the motor housing, and a rotor disposed on the inner periphery of the stator. The rotor has a rotor shaft that is rotatably supported by a pair of bearings. The pair of bearings are held by a bearing holder. The bearing holder has bearing mounting holes for mounting the pair of bearings at both ends in the axial direction. By mounting the bearing in the bearing mounting hole, the pair of bearings are held at a constant interval in the axial direction.

JP 2015-216707 A

  When bearings are attached to both ends in the axial direction of the bearing holder, it is necessary to provide bearing attachment holes, which complicates the structure. For example, in Patent Document 1, the bearing holder is a molded product made of zinc alloy die casting or the like, which is expensive to manufacture.

  Therefore, 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 motor housing in which at least a part of a stator is accommodated, a rotor including a shaft that is a rotating shaft, and a first bearing and a second bearing that rotatably support the shaft. The motor housing has an outer wall portion that is disposed radially outside the stator and extends in the axial direction, and a flange that extends radially inward from an outer edge portion on one axial side of the outer wall portion. And a cylindrical inner wall portion extending in the axial direction from at least a part of the radially inner inner edge of the flange portion, and a cylindrical bearing extending in the axial direction on the inner wall portion A housing is fixed, inner rings of the first bearing and the second bearing are fixed to the shaft, an outer ring of the first bearing is fixed to an inner surface of the inner wall, and an outer ring of the second bearing Before Characterized in that it is fixed to the inner surface of the bearing housing.

  According to the exemplary motor of the present invention, it is possible to maintain high rotation accuracy with a simple configuration.

FIG. 1 is a longitudinal end view of the motor according to the first embodiment of the present invention cut along a plane parallel to the axial direction. FIG. 2 is a diagram illustrating the rotor, the first bearing, and the second bearing. FIG. 3 is an end view around a bearing housing of another example of the motor according to the first embodiment of the present invention. It is. FIG. 4 is an end view around a bearing housing of an example of a motor according to a second embodiment of the present invention. FIG. 5 is an end view around a bearing housing of an example of a motor according to a third embodiment of the present invention. FIG. 6 is an end view around a bearing housing of an example of a motor according to a fourth embodiment of the present invention. FIG. 7 is an end view around a bearing housing of an example of a motor according to a fifth embodiment of the present invention. It is the vertical end elevation which cut | disconnected the motor concerning 5th Embodiment of this invention by the surface parallel to an axial direction.

  Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings. In the following description, the direction in which the rotation shaft of the motor extends is referred to as “axial direction”. A direction perpendicular to the rotation axis centering on the rotation axis of the motor is defined as a “radial direction”. Furthermore, the direction along the arc centered on the rotation axis of the motor is defined as “circumferential direction”. Further, on the basis of the state of FIG. 1, that is, the axial direction is “left-right direction”, the clockwise direction is “clockwise direction”, and the counterclockwise direction is “counterclockwise direction”. In the following description, the shape and positional relationship of each part will be described using each direction described above. The definition of the left-right direction is defined for convenience of description, and does not limit the direction and position when the motor is used.

  In the following description, an end view parallel to the axial direction is referred to as a “longitudinal sectional view”. Furthermore, in the following description, “parallel” and “vertical” not only indicate parallel and vertical in a strict sense, but also include substantially parallel and substantially vertical.

<1. First Embodiment>
<1.1 Outline of motor configuration>
A schematic configuration of a motor according to a first exemplary embodiment of the present invention will be described. FIG. 1 is a longitudinal end view of the motor according to the first embodiment of the present invention cut along a plane parallel to the axial direction. As shown in FIG. 1, the motor A according to this embodiment includes a motor housing 1, a stator 2, a rotor 3, a first bearing 41, a second bearing 42, a bearing housing 5, and a motor cover 6. And a drive substrate 7. A part of the stator 2 is disposed inside the motor housing 1. That is, at least a part of the stator 2 is accommodated in the motor housing 1.

  The rotor 3 includes a shaft 31 that is a rotating shaft. The shaft 31 is rotatably supported by the motor housing 1 and the bearing housing 5 via the first bearing 41 and the second bearing 42. That is, the first bearing 41 and the second bearing 42 support the shaft 31 in a rotatable manner. The rotor 3 of the motor A is disposed inside the stator 2 in the radial direction. That is, the motor A according to the present embodiment is an inner rotor type DC brushless motor.

<1.2 Motor housing configuration>
The motor housing 1 has an outer wall portion 11, an inner wall portion 12, and a flange portion 13. In the present embodiment, the outer wall portion 11 has a hollow cylindrical shape centering on the shaft 31 and extending in the axial direction. That is, the outer wall portion 11 is a cylindrical shape that is disposed on the radially outer side of the stator 2 and extends in the axial direction. The outer wall portion 11 may have a shape in which a part of the outer wall portion 11 is cut out in the circumferential direction. The flange portion 13 has a disk shape and has a through hole in the center. The outer peripheral edge portion of the flange portion 13 is connected to the left end portion of the outer wall portion 11 in FIG. That is, the flange portion 13 extends radially inward from the outer edge portion of the outer wall portion 11 on the one axial direction side.

  The inner wall portion 12 has a hollow cylindrical shape centering on the shaft 31 and extending in the axial direction. The edge portion of the through hole of the flange portion 13 is connected to the left end portion of the inner wall portion 12 in FIG. That is, the inner wall portion 12 has a cylindrical shape extending in the axial direction from the inner edge portion on the radially inner side of the flange portion. The inner wall portion 12 may have a shape in which a part of the inner wall portion 12 is cut out in the circumferential direction. The outer wall portion 11 and the inner wall portion 12 are arranged coaxially. The inner wall portion 12 is disposed so as to overlap the outer wall portion 11 in the radial direction. That is, at least a part of the inner wall portion 12 overlaps the outer wall portion 11 in the radial direction. The flange portion 13 connects the left end portions of the outer wall portion 11 and the inner wall portion 12 in the axial direction. That is, it arrange | positions on the same side of an axial direction on the basis of the flange part 13. As shown in FIG. However, it is not limited to this configuration. The motor housing 1 is formed by pressing a metal plate such as a sheet metal. However, it is not limited to this. For example, it may be formed by cutting.

  A first bearing 41 is fixed to the inner surface of the inner wall portion 12 of the motor housing 1. The 1st bearing 41 supports the shaft 31 rotatably. Therefore, the inner peripheral surface of the inner wall portion 12 has high dimensional accuracy, that is, the inner peripheral surface of the inner wall portion 12 has at least a high roundness and a smooth surface. In addition, a fixing portion 51, which will be described later, of the bearing housing 5 is fixed inside the inner wall portion 12 along with the first bearing 41 in the axial direction. That is, the cylindrical bearing housing 5 extending in the axial direction is fixed to the inner wall portion 12.

<1.3 Stator configuration>
The stator 2 is disposed between the outer wall portion 11 and the inner wall portion 12 of the motor housing 1 in the radial direction. The stator 2 includes a stator core 21, an insulator 22, and a coil 23. The stator core 21 is a laminated body in which a plurality of magnetic steel plates are laminated and fixed in the axial direction (FIG. 1, left-right direction). The stator core 21 has an annular yoke (not shown) and a plurality of teeth (not shown) extending radially inward from the yoke. The insulator 22 is disposed between the stator core 21 and the coil 23 and is formed of, for example, an electrically insulating member using a synthetic resin. The insulator 22 is made of an electrically insulating material such as enamel or rubber in addition to the synthetic resin. The coil 23 is formed by winding an electric wire around the outer periphery of the insulator 22 that covers the outer surface of the stator core 21. The stator 2 has an annular shape.

<1.4 Rotor configuration>
The rotor 3 is arranged on the radially inner side of the stator 2 with a predetermined gap. The rotor 3 includes a shaft 31, a rotor cylinder portion 32, a boss portion 33, a top surface portion 34, and a magnet 35. The rotor cylinder portion 32, the boss portion 33, and the top surface portion 34 are formed, for example, by pressing a metal plate such as a sheet metal. In addition, it is not limited to press work, Cutting etc. may be sufficient.

  The shaft 31 is a rotating shaft of the motor A. The shaft 31 has a cylindrical shape extending in the axial direction (left-right direction in FIG. 1). The shaft 31 protrudes to the left in FIG. 1 of the motor A, and a driven member (not shown) is attached to the tip thereof. Examples of the driven member include, but are not limited to, an impeller and a gear that generate an air flow by rotation. The shaft 31 is rotatably supported by the motor housing 1 and the bearing housing 5 fixed to the motor housing 1 via the first bearing 41 and the second bearing 42.

  The rotor cylinder portion 32 has a hollow cylindrical shape centering on the shaft 31 and extending along the axial direction. The top surface portion 34 has a disc shape with the shaft 31 as the center, and includes a through hole in the center. The top surface portion 34 extends radially inward from the right end portion of the rotor cylinder portion 32. That is, the shaft 31 is disposed in the through hole provided in the center of the top surface portion 34. The edge of the through hole is close to the outer peripheral surface of the shaft 31. The boss portion 33 has a cylindrical shape extending leftward in the axial direction from the edge of the through hole of the top surface portion 34. The shaft 31 is fixed to the inner peripheral surface of the boss portion 33. In addition, although press-fit is employ | adopted as fixation of the boss | hub part 33 and the shaft 31, other than this, adhesion | attachment, welding, screwing etc. can be mentioned, for example.

  The magnet 35 has a cylindrical shape with the shaft 31 as the center and extending in the axial direction. The inner peripheral surface of the magnet 35 is in contact with the outer peripheral surface of the rotor cylinder portion 32. The magnet 35 is fixed to the outer peripheral surface of the rotor cylinder portion 32. The magnet 35 is a surface magnet type (SPM: Surface Permanent Magnet), and different N poles and S poles are alternately arranged in the circumferential direction. In the present embodiment, the magnet 35 is inserted into the rotor cylinder portion 32 and fixed with an adhesive.

  However, the fixing method of the magnet 35 is not limited to the above-described fixing method, and for example, press-fitting, light press-fitting, welding, or the like can be employed. When the magnet 35 and the rotor cylinder part 32 are separate bodies, it is easy to change the specifications of the magnet 35, for example, the number of magnetic poles and magnetic force. Further, after the rotor cylinder portion 32 and the boss portion 33 are formed, the rotor 3 may be manufactured by outsert molding in which a magnet 35 is formed by injection molding outside the rotor cylinder portion 32 using a separate mold. Good. When the rotor cylinder portion 32 and the magnet 35 are manufactured as a molded body, it is possible to suppress the denaturation of the magnet 35 due to a force in press-fitting or heat in welding.

  As described above, in the rotor 3, the shaft 31 and the magnet 35 are fixed via the rotor cylinder portion 32, the boss portion 33, and the top surface portion 34. That is, the shaft 31 and the magnet 35 do not move relative to each other. Thereby, since the shaft 31 is rotatably supported by the first bearing 41 and the second bearing 42, the magnet 35 rotates together with the rotation of the shaft 31.

<1.5 Bearing configuration>
In the motor A, the shaft 31 is attached to the first bearing 41 and the second bearing 42. The first bearing 41 and the second bearing 42 rotatably support the shaft 31 at different positions in the axial direction. The first bearing 41 includes an outer ring 411, an inner ring 412, and a ball 413. The outer ring 411 and the inner ring 412 are arranged coaxially, and a plurality of balls 413 are arranged in the circumferential direction at a portion between the outer ring 411 and the inner ring 412. The first bearing 41 is a so-called rolling bearing (ball bearing). The first bearing 41 may be an oil-impregnated bearing. Instead of the ball, a configuration using a roller that is a cylindrical rotating body may be used. Further, the first bearing 41 may be a bearing different from the second bearing 42. For example, the first bearing 41 may be an oil-impregnated bearing and the second bearing may be a ball bearing.

  The outer ring 411 of the first bearing 41 is in contact with the inner peripheral surface of the inner wall portion 12 of the motor housing 1. The outer ring 411 is fixed to the inner peripheral surface of the inner cylinder 12. The inner ring 412 of the first bearing 41 is provided with the shaft 31 at the center. The inner ring 412 is fixed to the outer peripheral surface of the shaft 31. The shaft 31 is fixed to the inner ring 412 by press fitting, and the outer ring 411 is fixed to the inner wall portion 12 by light press fitting. That is, the outer ring 411 of the first bearing 41 is fixed to the inner surface of the inner wall portion 12.

  The fixing between the shaft 31 and the inner ring 412 is not limited to press-fitting, and for example, insertion, light press-fitting, adhesion, welding, screwing, or the like can be employed. Further, the fixing between the outer ring 411 and the inner wall portion 12 is not limited to light press fitting, and for example, press fitting, insertion, adhesion, welding, screwing, or the like can be employed. In the first bearing 41, it is possible to widely adopt a fixing method in which the frictional force due to fixing between the inner ring 412 and the outer peripheral surface of the shaft 31 is larger than the frictional force due to fixing between the outer ring 411 and the inner peripheral surface of the inner wall portion 12. it can.

  A part of the first bearing 41 protrudes leftward from the left end in the axial direction of the inner wall portion 12 of the motor housing 1. The portion of the first bearing 41 protruding in the axial direction from the motor housing 1 is used for connecting the motor A and another member to the spigot joint. In addition, when there is no member couple | bonded with the motor A, or when attaching by methods other than a spigot joint, the 1st bearing 41 may be arrange | positioned and stored in the inner wall part 12 in the axial direction.

  The second bearing 42 includes an outer ring 421, an inner ring 422, and a ball 423. The second bearing 42 is a so-called ball bearing having the same configuration as the first bearing 41. As for the 2nd bearing 42, the outer ring | wheel 421 contacts the internal peripheral surface of the bearing holding part 52 which the bearing housing 5 mentions later. The outer ring 421 is fixed to the inner peripheral surface of the bearing holding portion 52. That is, the outer ring 421 of the second bearing 42 is fixed to the inner surface of the bearing housing 5.

  The inner ring 422 is fixed to the outer peripheral surface of the shaft 31. The inner ring 422 is fixed to the shaft 31 by press fitting. The outer ring 421 is fixed to the bearing holding portion 52 by light press fitting. In the second bearing 42 as well, as with the first bearing 41, the outer ring 421 and the inner ring 422 are fixed to the bearing holding portion 52 and the shaft 31, respectively, by press fitting, light press fitting, adhesion, welding, screwing, or the like. Can do. In the second bearing 42, a fixing method in which the frictional force due to the fixation between the inner ring 422 and the outer peripheral surface of the shaft 31 is larger than the frictional force due to the fixation between the outer ring 421 and the inner peripheral surface of the bearing holding portion 52 is widely adopted. can do. That is, the inner rings 412 and 422 of the first bearing 41 and the second bearing 42 are fixed to the shaft 31.

<1.6 Bearing housing configuration>
The bearing housing 5 has a cylindrical shape with the shaft 31 as the center and extending in the axial direction. Note that the bearing housing 5 may have a shape in which a part is notched in the circumferential direction. The bearing housing 5 is coaxial with the outer wall portion 11 and the inner wall portion 12 of the motor housing 1. The bearing housing 5 has a fixed portion 51 at the left end in FIG. 1 and a bearing holding portion 52 at the right end. That is, the bearing housing 5 includes a fixed portion 51 fixed to the inner wall portion 12 at one end portion in the axial direction, and a bearing holding portion 52 holding the second bearing 42 at the other end portion.

  The fixed portion 51 has a cylindrical shape with a smaller outer diameter on the outer peripheral surface as compared with other portions of the bearing housing 5. That is, the outer diameter of the outer peripheral surface of the fixed portion 51 is smaller than the outer diameter of the other part of the bearing housing 5. The fixing portion 51 is fixed to the inner peripheral surface of the inner wall portion 12 of the motor housing 1. That is, the fixed portion 51 is disposed inside the inner wall portion 12. In addition, although the fixing | fixed part 51 is fixed to the inner wall part 12 by press injection, it is not limited to this. For example, fixing methods such as light press-fitting, adhesion, welding, and screwing may be employed. Alternatively, a configuration may be adopted in which a female screw is formed on the inner peripheral surface of the inner wall portion 12, a male screw is formed on the outer peripheral surface of the fixing portion 51, and the fixing portion 51 is screwed and fixed to the inner wall portion 12.

  An outer ring 411 of the first bearing 41 is fixed to the inner peripheral surface of the inner wall portion 12. Therefore, the inner peripheral surface of the inner wall portion 12 has high dimensional accuracy. By increasing the dimensional accuracy of the fixed portion 51 of the bearing housing 5, it is possible to press-fit the bearing housing 5 into the inner peripheral surface of the inner wall portion 12.

  By fixing the fixing portion 51 to the inner wall portion 12, the bearing housing 5 overlaps the outer wall portion 11 in the radial direction. That is, the bearing housing 5 is disposed inside the motor housing 1. In the motor A shown in FIG. 1, the bearing housing 5 is accommodated in the motor housing 1 in the radial direction and the axial direction, but is not limited thereto. For example, the bearing housing 5 may protrude from the motor housing 1 on the right side, that is, the bearing holding portion 52 side in the axial direction.

The distal end side of the fixing portion 51, that is, the left end side in FIG. 1 has an end surface portion 511 extending inward. In other words, the fixing portion 51 has an end surface portion 511 that includes a through hole that extends radially inward from the axial tip of the fixing portion 51 and penetrates in the axial direction around the rotation axis.
The end surface portion 511 has a disk shape and has a through hole at the center. The shaft 31 penetrates the through hole. The shaft 31 penetrating the through hole does not come into contact with the end surface portion 511, that is, a gap is formed between the edge of the through hole and the shaft 31. Moreover, the strength of the fixing portion 51 is increased by providing the end surface portion 511. Therefore, when the fixing portion 51 is press-fitted into the inner wall portion 12, it is possible to suppress the fixing portion 51 from being deformed and not being fixed or the frictional force being weakened.

  In the bearing housing 5, the fixed portion 51 has a smaller outer diameter than portions other than the fixed portion 51. The outer peripheral surface of the bearing housing 5 has a step in which the end of the fixed portion 51 on the bearing holding portion 52 side, that is, the right end is bent radially outward. The step of the fixing portion 51 comes into contact with the right end of the inner wall portion 12 in the axial direction when the fixing portion 51 is press-fitted into the inner wall portion 12. Then, when the right end portion of the inner wall portion 12 and the step contact each other, the fixing portion 51 stops moving in the axial direction to the inner peripheral surface of the inner wall portion 12. That is, the fixing portion 51 having a step can prevent the fixing portion 51 of the bearing housing 5 from entering the inside of the inner wall portion 12 too much.

  The fixing portion 51 is press-fitted from a through hole on the right side of the inner peripheral surface of the inner wall portion 12 of the motor housing 1. Then, the first bearing 41 is lightly press-fitted from the left through hole on the inner peripheral surface of the inner wall portion 12. The first bearing 41 is fixed to the left of the inner peripheral surface of the inner wall portion 12. In addition, the fixing portion 51 of the bearing housing 5 is fixed to the right side of the inner peripheral surface of the inner wall portion 12. The first bearing 41 and the end surface portion 511 are fixed with a gap inside the inner wall portion 12. A first elastic member 14 is disposed in the gap between the inner wall portions 12. The first elastic member 14 is an annular member. The first elastic member 14 is a so-called wave washer having a shape that undulates along the circumferential direction. In addition, the 1st elastic member 14 is not limited to a wave washer, For example, a coil spring, a disc spring, etc. may be sufficient. Further, the first elastic member 14 is not limited to an annular shape. For example, an irregular elastic body such as rubber or an elastic body using a fluid such as air or oil may be used.

  A part of the end surface portion 411 may be cut and raised to form the first elastic member 14. As the 1st elastic member 14, the structure which can make axial force act on the outer ring | wheel 411 of the 1st bearing 41 is employable widely.

  The first elastic member 14 comes into contact with the outer ring 411 of the first bearing 41 and the end surface portion 511 of the fixed portion 51 in a state where it is elastically deformed in the axial direction in advance. That is, the first elastic member 14 is disposed between the first bearing 41 and the fixed portion 51. The first elastic member 14 is in contact with the end surface portion 511 and the outer ring 411 of the first bearing 41. The first elastic member 14 is elastically deformed in advance and is in contact with the outer ring 411 and the end surface portion 511. Therefore, a force that attempts to return the first elastic member 14 in the axial direction acts on the outer ring 411 and the end surface portion 511.

  The frictional force due to the fixation between the inner wall portion 12 and the outer ring 411 of the first bearing 41 is smaller than the frictional force due to the fixation between the inner wall portion 12 and the outer peripheral surface of the fixing portion 51. Therefore, the outer ring 411 moves in a direction away from the end surface portion 511, that is, leftward by the elastic force of the first elastic member 14. Thereby, it is possible to suppress rattling due to the gap between the outer ring 411 and the ball 413 and rattling due to the gap between the ball 413 and the inner ring 412. By suppressing the rattling of the first bearing 41, the rotation of the first bearing 41 is stabilized, and the life of the first bearing 41 can be extended. Further, by suppressing the rattling of the first bearing 41, it is possible to suppress vibration and vibration of the shaft 31 when the motor A is driven.

  The bearing holding portion 52 has a cylindrical shape with a larger inner diameter on the inner peripheral surface than other portions of the bearing housing 5. That is, the inner diameter of the inner peripheral surface of the bearing holding portion 52 is larger than the inner diameter of the other part of the bearing housing 5. The bearing holding part 52 is in contact with the outer ring 421 of the second bearing 42 on the inner peripheral surface. The outer ring 421 of the second bearing 42 is fixed to the inner peripheral surface of the bearing holding portion 52. At the front end of the bearing holding portion 52, that is, the right end in FIG. 1, the bearing holding portion 52 is provided with an annular portion 521 extending outward. That is, the front end in the axial direction of the bearing holding portion 52 includes an annular portion 521 that extends radially outward from the front end in the axial direction. The strength of the bearing holding portion 52 is increased by the annular portion 521, and the bearing holding portion 52 is not easily deformed.

  In the bearing housing 5, the portion other than the fixed portion 51 of the bearing housing 5 has a larger diameter than the fixed portion 51. Therefore, the section modulus and the pole section coefficient can be increased, and deformation such as bending and twisting of the bearing housing 5 can be suppressed.

  By using the bearing housing 5 shown in the present embodiment, the second bearing 42 can have the same configuration as the first bearing 41. Thereby, the kind of structural member can be reduced and it becomes possible to reduce manufacturing cost.

  The support of the shaft 31 by the first bearing 41 and the second bearing 42 will be described. FIG. 2 is a diagram illustrating the rotor, the first bearing, and the second bearing. In FIG. 2, the directions of the load W due to the weight of the rotor 3, the load F <b> 1 that acts on the shaft 31 from the first bearing 41, and the load F <b> 2 that acts on the shaft 31 from the second bearing 42 are indicated by arrows.

  In FIG. 2, the axial position of the center of gravity of the rotor 3 is C1. The first bearing 41 and the second bearing 42 are arranged in the axial direction on the same side with respect to the center of gravity position C1 of the rotor 3 and on the left side in FIG. In other words, the shaft 31 is supported by the first bearing 41 and the second bearing 42 in a cantilever state. In FIG. 2, the center of gravity position C <b> 1 of the rotor 3 is on the right side of the second bearing 42. Therefore, a moment M acting in the direction in which the center of gravity is lowered around the second bearing 42, that is, in the clockwise direction in FIG.

  The shaft 31 is maintained horizontally by the first bearing 41 and the second bearing 42. Therefore, the moment M generated in the shaft 31 is supported by the first bearing 41 disposed on the opposite side of the center of gravity position C1 with the second bearing 42 interposed therebetween. That is, when the shaft 31 is supported in a cantilever state, the load F <b> 1 due to the moment M acts on the first bearing 41. A clockwise moment M is acting, and the load F1 acting on the first bearing 41 is an upward load.

Here, the load F1 acting on the first bearing 41 from the shaft 31 and the load F2 acting on the second bearing 42 from the shaft 31 will be described. The axial distance between the first bearing 41 and the second bearing 42 is L0, the axial distance from the second bearing 42 to the center of gravity C1 is L1, and the load due to the weight of the rotor 3 is W. The moment M acting on the shaft 31 around the second bearing 42 is expressed by the following equation.
M = W × L1
And the load F1 which acts on the shaft 31 from the 1st bearing 41 when this moment M is acting is represented by the following formula | equation.
F1 = M / L0 = W × L1 / L0
Since the moment M is clockwise, the load acting on the first bearing 41 is upward. A load F1 acting on the shaft 31 from the first bearing 41 is downward. Further, the load F2 acting on the shaft 31 from the second bearing is upward. A load W due to the weight of the rotor 3 acts downward on the shaft 31. When the load acting on the shaft 31 is arranged, the load F2 acting on the second bearing 42 is expressed by the following equation.
F2 = W (1 + L1 / L0)

  According to the law of action and reaction, the load F1 acting on the shaft 31 from the first bearing 41 and the load acting on the first bearing 41 from the shaft 31 are the same. Similarly, the load F2 acting on the shaft 31 from the second bearing 42 and the load acting on the second bearing 42 from the shaft 31 are the same. Therefore, in the description, for the sake of convenience, the load F1 acting on the first bearing 41 and the load F2 acting on the second bearing 42 will be described.

  From the above equation, the load F1 acting on the first bearing 41 increases as the axial distance L1 from the second bearing 42 to the center of gravity C1 increases, and the distance between the first bearing 41 and the second bearing 42 decreases. It gets bigger. Similarly, the load F2 acting on the second bearing 42 also increases as the axial distance L1 from the second bearing 42 to the center of gravity C1 increases, and as the distance between the first bearing 41 and the second bearing 42 decreases. .

  In the motor A, when the shapes of the stator 2 and the rotor 3 are the same, the distance (L0 + L1) between the first bearing 41 and the gravity center position C1 of the rotor 31 can be constant or substantially constant regardless of the position of the second bearing 42. . At this time, when the axial distance L0 between the first bearing 41 and the second bearing 42 becomes longer, the axial distance L1 between the second bearing 42 and the center of gravity position C1 of the rotor 3 becomes shorter.

  In the case of the motor A shown in this embodiment, the fixed portion 51 of the bearing housing 5 is fixed to the inner wall portion 12, and the second bearing 42 is fixed by the bearing holding portion 52 at the end opposite to the fixed portion 51. . As a result, the axial distance L0 between the first bearing 41 and the second bearing 42 is increased, and the axial distance L1 from the second bearing 42 to the center of gravity position C1 is decreased. It can be seen that the load F1 acting on the first bearing 41 and the load F2 acting on the second bearing 42 are reduced.

  That is, like the motor A shown in the present embodiment, the load acting on the first bearing 41 and the second bearing 42 can be reduced by fixing the second bearing 42 to the bearing housing 5. Thereby, the frictional force acting between the outer ring 411 and the inner ring 412 of the first bearing 41 and the ball 413 can be reduced. Further, the frictional force acting between the outer ring 421 and the inner ring 422 of the second bearing 42 and the ball 423 can be reduced. By reducing the frictional force of the first bearing 41 and the second bearing 42, the life of the first bearing 41 and the second bearing 42 can be extended. Further, since the moment M is also reduced, it is possible to suppress the vibration and vibration of the rotation of the shaft 31 when the motor A is driven.

  The axial position of the center of gravity of the rotor 3 can be set between the first bearing 41 and the second bearing 42 by adjusting the length of the bearing housing 5. In this case, although the axial length of the motor A is increased, the support of the shaft 31 by the first bearing 41 and the second bearing is not in a cantilever state. As a result, the loads F1 and F2 acting on the first bearing 41 and the second bearing 42 from the shaft 31 can be further reduced. That is, the lifetime of the first bearing 41 and the second bearing 42 can be further extended. In addition, since the support of the shaft 31 is not in a cantilever state, it is possible to further enhance the effect of reducing rotational vibration and vibration when the motor A is driven.

  Here, a configuration in which the axial distance between the first bearing 41 and the second bearing 42 is increased and a configuration using the bearing housing 5 of the present embodiment are compared. In the motor housing 1 shown in FIG. 1, for example, the length of the first bearing 41 and the second bearing 42 can be increased by increasing the length of the inner wall portion 12. However, when the motor housing 1 is manufactured by press working, if the length of the inner wall portion 12 in the axial direction is increased, the inner wall portion 12 is thinned. When the inner wall portion 12 is thinned, the strength of the portion that holds the bearing is reduced, and vibration or rotational vibration occurs.

  On the other hand, in the motor A shown in the present embodiment, by using the bearing housing 5, it is not necessary to reduce the thickness of the inner wall portion 12 and lengthen it in the axial direction, and the strength can be maintained. In addition, the axial distance between the first bearing 41 and the second bearing 42 can be increased. Thereby, the load to the 1st bearing 41 and the 2nd bearing 42 can be reduced, and the vibration of the shaft 31 at the time of the drive of the motor A and the run-out of rotation can be reduced. Further, since both the motor housing 1 and the bearing housing 5 are manufactured by press working, it is possible to keep the cost required for manufacturing low. In the motor A of the present embodiment, the bearing housing 5 holds the second bearing 42. Since the bearing housing 5 is fixed to the inner wall portion 12, the axial length of the outer wall portion 11 is longer than the length of the inner wall portion 12 in the bearing direction. That is, the axial length of the outer wall portion 11 is longer than the axial length of the portion of the inner wall portion 12 that overlaps the outer wall portion 11 in the radial direction.

<1.7 Motor Cover and Drive Board Configuration>
The motor cover 6 is an exterior member that covers the right side of the motor A. The motor cover 6 has a cylindrical shape extending in the axial direction, and a right end in the axial direction is closed. That is, the motor cover 6 has a bottomed cylindrical shape. The motor cover 6 has a through hole on the left side of the motor cover 6. The through hole on the left side of the motor cover 6 is in contact with the insulator 22 covering the stator core 21. The stator core 21 is fixed to the insulator 22. The motor cover 6 prevents foreign matters such as dust, dust and moisture from entering the motor A and also serves as an electromagnetic wave shield.

  The drive substrate 7 is disposed on the right side of the stator core 21. The drive board 7 is fixed to the insulator 22. The drive board 7 is mounted with an inverter circuit, a control circuit, etc. (all not shown). The drive substrate 7 supplies a current to each of the plurality of coils 23 wound around the teeth of the stator core 21. As described above, the magnet 35 has alternately different magnetic poles arranged in the circumferential direction. By supplying current to the coil 23, magnetic force is generated according to the circumferential position of the magnetic pole of the magnet 35, and the rotor 3 rotates. That is, the rotor 3 rotates by switching the coil 23 that supplies current at a predetermined timing. In order to rotate the rotor 3 accurately, an accurate position in the circumferential direction of the magnet 35 is required.

  Therefore, a rotation detector 71 is mounted on the drive board 7 on the right side of the magnet 35. The rotation detector 71 has a detection surface 711 for detecting the magnetic flux density on the upper surface. The rotation detection unit 71 includes a Hall element that converts the magnetic flux density passing through the detection surface 711 into a voltage. The rotation detection surface 711 faces the right end of the magnet 35 with a space in the axial direction. As described above, the magnet 35 has different magnetic poles arranged in the circumferential direction. When the magnet 35 rotates, the magnetic flux density passing through the detection surface 711 changes. Thereby, the voltage converted by the Hall element also changes. The rotation detection unit 71 transmits a voltage change to the control circuit. The control circuit detects the position of the magnet 35, that is, the circumferential direction of the rotor 3 based on the change in voltage.

<1.8 Modification 1 of First Embodiment>
A modification of the motor according to the first exemplary embodiment of the present invention will be described with reference to the drawings. FIG. 3 is an end view around a bearing housing of another example of the motor according to the first embodiment of the present invention. The motor A <b> 1 shown in FIG. 3 is configured to further include the second elastic member 15 in the bearing holding portion 52. Other than that, it is the same structure as the motor A shown in FIG.

  As shown in FIG. 3, a stepped portion 522 that bends in the direction of the shaft 31 is provided at the left end portion inside the bearing holding portion 52. That is, the bearing holding portion 52 includes a step portion 522 that is bent radially inward at the end portion on the fixed portion 51 side. The second elastic member 15 is disposed on the left side of the second bearing 42 disposed inside the bearing holding portion 52. That is, the second elastic member 15 is disposed between the second bearing 42 and the step portion 522.

  The second elastic member 15 has an annular shape and is a wave washer. The second elastic member 15 can also employ a configuration other than the wave washer, such as a coil spring or a disc spring. Further, the second elastic member 15 is not limited to an annular shape. For example, an irregular elastic body such as rubber or an elastic body using a fluid such as air or oil may be used.

  The second elastic member 15 contacts the outer ring 421 of the second bearing 42 and the stepped portion 522 of the bearing holding portion 52. That is, the second elastic member 15 is in contact with the step portion 522 and the outer ring 421 of the second bearing 42. The second elastic member 15 is elastically deformed in advance and contacts the outer ring 421 and the stepped portion 522. As a result, a force to return the second elastic member 15 to the original axial direction acts on the outer ring 421 and the step portion 522.

  The second elastic member 15 pushes the outer ring 421 in the direction away from the step portion 522 along the axial direction. Thereby, it is possible to eliminate rattling caused by the gap between the outer ring 421 and the ball 423 and rattling caused by the gap between the ball 423 and the inner ring 422. The second elastic member 15 has the same configuration as that of the first elastic member 14, and since the stepped portion 522 is provided in the bearing holding portion 52, the second elastic member 15 may be disposed. Easy.

  In addition, although motor A1 shown in this modification has the 1st elastic member 14 and the 2nd elastic member 15, it is not limited to this. Only the second elastic member 15 may be provided. Moreover, when there is little shakiness of the 1st bearing 41 and the 2nd bearing 42, you may abbreviate | omit the 1st elastic member 14 and the 2nd elastic member 15. FIG.

<2. Second Embodiment>
A motor according to a second exemplary embodiment of the present invention will be described with reference to the drawings. FIG. 4 is an end view around a bearing housing of an example of a motor according to a second embodiment of the present invention. The motor B shown in FIG. 4 has a bearing housing 5b and a second bearing 42b. Other than that, it is the same structure as the motor A shown in FIG. Therefore, substantially the same parts are denoted by the same reference numerals and detailed description of the same parts is omitted.

  In the bearing housing 5 b shown in FIG. 4, the inner diameter of the inner peripheral surface of the bearing holding portion 52 b is larger than the inner diameter of the inner peripheral surface of the inner wall portion 12. By using the bearing housing 5b having such a configuration, the second bearing 42b including the outer ring 421b larger than the outer diameter of the outer ring 411 of the first bearing 41 can be used. The inner ring 412 of the first bearing 41 and the inner ring 422b of the second bearing 42b both pass through the shaft 31 and are fixed to the outer peripheral surface of the shaft 31. Therefore, the inner diameters of the inner ring 412 and the inner ring 422b are the same. The outer diameter of the outer ring 421b is larger than the outer diameter of the outer ring 411. Therefore, the second bearing 42b has a ball 423b having a larger diameter than the ball 413 of the first bearing 41. By making the outer diameter of the ball 423 b larger than the outer diameter of the ball 413 of the first bearing 41, the load resistance in the radial direction of the second bearing 42 b can be made larger than that of the first bearing 41.

  For example, it is assumed that the shaft 31 is cantilevered by the first bearing 41 and the second bearing 42b. In this case, as described above, a larger load than the first bearing 41 acts on the second bearing 42b. Therefore, the second bearing 42b that can support a larger load than the first bearing 41 is employed as the second bearing 42b in which the load from the shaft 31 is increased. Thereby, the life of the second bearing 42b is extended.

  Further, by increasing the inner diameter of the inner peripheral surface of the bearing holding portion 52b, the difference (step) in the inner diameter of the step portion 522 can be increased. Thereby, when attaching the 2nd elastic member 15, it is possible to enlarge a contact area with the 2nd elastic member 15. FIG. Therefore, the second elastic member 15 can be easily attached.

  In this embodiment, an example is given in which the ball diameter increases as the outer ring of the bearing increases, but the present invention is not limited to this. For example, there is a bearing in which the number of balls increases as the outer ring becomes larger. In the bearing, when the number of balls increases, rattling is less likely to occur and the accuracy of rotation increases. That is, by adopting a bearing with an increased number of balls, the effect of suppressing the vibration of the shaft 31 and the vibration of the rotation is enhanced.

<2.1 Modification of Second Embodiment>
In the example of the second embodiment illustrated in FIG. 4, the bearing housing 5 b includes a bearing holding portion 52 b in which a second bearing 42 b having an outer ring 421 b having a larger diameter than the first bearing 41 can be disposed. However, the present invention is not limited to this, and the bearing housing 5b may include a bearing holding portion 52b in which a second bearing having an outer ring having a smaller diameter than the first bearing 41 can be disposed. In this case, the inner peripheral surface of the second bearing 52b is formed to have a smaller diameter than the inner peripheral surface of the portion of the bearing housing 5b excluding the fixed portion 51.

<3. Third Embodiment>
An example of a motor according to a third exemplary embodiment of the present invention will be described with reference to the drawings. FIG. 5 is an end view around a bearing housing of an example of a motor according to a third embodiment of the present invention. The motor C shown in FIG. 5 has a bearing housing 5c. Other than that, it is the same structure as the motor A shown in FIG. Therefore, substantially the same parts are denoted by the same reference numerals and detailed description of the same parts is omitted.

  The bearing housing 5c has a cylindrical shape extending in the axial direction. And the bearing housing 5c is provided with the fixing | fixed part 51 by which the outer peripheral surface was formed in the diameter smaller than the other part at the left end. In the bearing housing 5c, the part other than the fixed part 51 is a cylinder having the same inner diameter and outer diameter in any part in the axial direction. And the bearing housing 5c is provided with the bearing holding | maintenance part 52c by which the 2nd bearing 42 is hold | maintained at the right end. The outer diameter and inner diameter of the bearing holding portion 52c are the same as the outer diameter and inner diameter of the intermediate portion in the axial direction of the bearing housing 5c.

  Since the bearing housing 5c has a cylindrical shape other than the fixed portion 51, it is possible to save labor for manufacturing. Further, since the inner diameter of the bearing holding portion 52c is the same as that of the intermediate portion, the position where the second bearing 42 is held can be adjusted.

  In the bearing housing 5 c of this embodiment, the inner diameter of the inner peripheral surface of the bearing holding portion 52 c is the same as the inner diameter of the inner peripheral surface of the inner wall portion 12. Therefore, the same second bearing 42 as the first bearing 41 can be used. However, it is not limited to this. When the second bearing uses a bearing having an outer diameter different from that of the first bearing 41, the inner diameter of the inner seed surface of the bearing holding portion 52c may be smaller or larger than the inner diameter of the inner peripheral surface of the inner wall portion 12. Also good. The bearing housing 5 c is configured to fix the fixing portion 51 to the inner peripheral surface of the inner wall portion 12. The bearing housing 5 c of this embodiment can be used for a motor that uses a second bearing whose outer diameter is larger than the inner diameter of the inner peripheral surface of the fixed portion 51.

<4. Fourth Embodiment>
An example of the motor according to the fourth exemplary embodiment of the present invention will be described with reference to the drawings. FIG. 6 is an end view around a bearing housing of an example of a motor according to a fourth embodiment of the present invention. The motor D shown in FIG. 6 employs a bearing housing 5d and a second bearing 42d. Other than that, it is the same structure as the motor A shown in FIG. Therefore, substantially the same parts are denoted by the same reference numerals and detailed description of the same parts is omitted.

  The bearing housing 5d shown in FIG. 6 has a cylindrical shape extending in the axial direction. The bearing housing 5d is a cylinder having the same inner diameter and outer diameter at any part in the axial direction. In the bearing housing 5 d, the left end fixing portion 51 c is fixed to the inner peripheral surface of the inner wall portion 12. Therefore, the outer diameter of the bearing housing 5d is the same as or substantially the same as the inner diameter of the inner peripheral surface of the inner wall portion 12. The inner diameter of the inner peripheral surface of the bearing housing 5d is smaller than the inner diameter of the inner peripheral surface of the inner wall portion 12.

  The bearing housing 5d has a bearing holding portion 52d that holds the second bearing 42d at the right end. The first bearing 41 is held on the inner peripheral surface of the inner wall portion 12, and the second bearing 42 is held on the inner peripheral surface of the bearing holding portion 52d. Therefore, the outer diameter of the outer ring 421d of the second bearing 42d is smaller than the outer diameter of the outer ring 411 of the first bearing 41. Since the inner rings 412 and 422d of the first bearing 41 and the second bearing 42d are both fixed to the shaft 31, they have the same inner diameter. Therefore, the ball 423d of the second bearing 42d has a smaller diameter than the ball 413 of the first bearing 41. In the bearing, the smaller the ball diameter, the harder the shafts of the inner ring and outer ring are displaced during rotation. That is, the rotation accuracy is high. By adopting the second bearing 42d, it is possible to suppress vibration of the shaft 31 and vibration of rotation.

  In addition, since the bearing housing 5d in the present embodiment has a cylindrical shape, it is possible to reduce the manufacturing cost required for processing the bearing housing 5c. Note that the bearing housing 5d of this embodiment can be used for a motor that uses a second bearing having an outer diameter smaller than the inner diameter of the inner peripheral surface of the fixed portion 51.

<5. Fifth Embodiment>
An example of a motor according to a fifth exemplary embodiment of the present invention will be described with reference to the drawings. FIG. 7 is an end view around a bearing housing of an example of a motor according to a fifth embodiment of the present invention. The motor E shown in FIG. 7 employs a bearing housing 5e and a second bearing 42e. Other than that, it is the same structure as the motor A shown in FIG. Therefore, substantially the same parts are denoted by the same reference numerals and detailed description of the same parts is omitted.

  The bearing housing 5e shown in FIG. 7 is a cylinder alarm. In other words, the outer peripheral surface of the bearing housing 5e has the same outer diameter at all portions in the axial direction. In addition, the inner peripheral surface of the bearing housing 5e has the same outer diameter in all axial portions. In the bearing housing 5 e, the left end fixing portion 51 e is fixed to the outer peripheral surface of the inner wall portion 12. The inner wall portion 12 is press-fitted into the inner peripheral surface of the fixed portion 51e. The fixing of the inner wall portion 12 and the fixing portion 51e is not limited to press-fitting. For example, adhesion, welding, screwing, or the like may be used.

  The bearing housing 5e has a bearing holding portion 52e at the right end. The bearing holding portion 52e is fixed with an outer ring 421e of the second bearing 42e disposed on the inner peripheral surface. Since the inner wall portion 12 is press-fitted into the bearing housing 5e, the outer ring 421e of the second bearing 42e is larger than the outer ring 411 of the first bearing 41. That is, the bearing housing 5 e of this embodiment can be used for a motor that uses a second bearing whose outer ring is larger than the outer ring 411 of the first bearing 41.

  Further, the bearing housing 5e of the present embodiment has an outer diameter of the outer peripheral surface and an inner diameter of the inner peripheral surface larger than those of the bearing housing press-fitted into the inner peripheral surface of the inner wall portion 12. Thereby, the section modulus and the pole section coefficient of the bearing housing 5e are large. Accordingly, deformation such as bending and twisting of the bearing housing 5e can be suppressed.

  In the motor E of the present embodiment, the fixing portion 51e of the bearing housing 5e is fixed to the outer peripheral surface of the inner wall portion 12, and the first bearing 41 is fixed to the inner peripheral surface. Therefore, the fixing portion 51 e can be fixed to the inner wall portion 12 by overlapping the first bearing 41 in the axial direction. Thereby, it is possible to shorten the length of the inner wall part 12 in the axial direction.

<5.1 Modification of Fifth Embodiment>
As the bearing housing 5e of the present embodiment, the inner diameter of the inner peripheral surface of the fixed portion 51e may be larger than the inner diameter of the inner peripheral surface of the other part of the bearing housing 5e. The inner diameter of the inner peripheral surface of the bearing holding portion 52e may be smaller than the inner diameter of the inner peripheral surface of the other part of the bearing housing 5e. Note that the outer diameter of the outer ring of the second bearing is the same as the outer diameter of the outer ring of the first bearing by making the inner diameter of the inner peripheral surface of the bearing holding portion 52e the same as the inner diameter of the inner peripheral surface of the inner wall portion 12. can do.

<6. Sixth Embodiment>
An example of a motor according to a fifth exemplary embodiment of the present invention will be described with reference to the drawings. FIG. 8 is a longitudinal end view of the motor according to the fifth embodiment of the present invention, cut along a plane parallel to the axial direction. The motor F shown in FIG. 8 employs a motor housing 1f. Other than that, it is the same structure as the motor A shown in FIG. Therefore, substantially the same parts are denoted by the same reference numerals and detailed description of the same parts is omitted.

  As shown in FIG. 8, in the motor housing 1 f of the motor F, the inner wall portion 12 f has a cylindrical shape extending from the radially inner edge of the flange portion 13 to the left side in the axial direction. In other words, the inner wall portion 12f extends in the axial direction on the opposite side of the outer wall portion 11 with the flange portion 13 interposed therebetween.

  A first bearing 41 is fixed to the inner peripheral surface of the inner wall portion 12 f on the left side, that is, on the tip end side in the axial direction when viewed from the flange portion 13. Further, a fixing portion 51 of the bearing housing 5 is fixed on the right side of the inner peripheral surface of the inner wall portion 12f, that is, on the side close to the flange portion 13.

  In the motor housing 1f, the inner wall portion 12f protrudes to the outside. The first bearing 41 and the fixing portion 51 of the bearing flange 5 are fixed on the inner peripheral surface of the inner wall portion 12f protruding in the axial direction. Thereby, the distance between the first bearing 41 and the second bearing 42 can be increased. Further, the inner wall portion is not disposed between the flange portion 13 and the rotor cylinder portion 32. For this reason, it is possible to make the flange part 13 close to the rotor cylinder part 32 as compared with the configuration in which the inner wall part extends inside the motor housing.

  From the above, the motor F of the present embodiment can be reduced in size because the length of the outer wall portion 11 can be shortened compared to a motor having a motor housing with an inner wall portion extending inward. It is. In addition, you may use the outer peripheral surface of the inner wall part 12f for the spigot connection with an external apparatus.

  Moreover, in this embodiment, although the bearing housing 5 is employ | adopted, it is not limited to this. For example, even if the bearing housing 5b shown in the second embodiment is employed, the same configuration can be obtained. In the present embodiment, a bearing housing having a configuration in which the motor housing and the bearing housing are fixed by fixing the fixing portion to the inner peripheral surface of the inner wall portion can be widely used.

  In the motors shown in the above embodiments, the distance between the first bearing and the second bearing can be adjusted by the bearing housing. Further, by combining the motor housing and the bearing housing, it is possible to attach a second bearing having different configurations, for example, the outer diameter of the outer ring and the diameter of the ball.

  As mentioned above, although embodiment of this invention was described, if it is in the range of the meaning of this invention, embodiment may be variously deformed.

  The present invention can be used in, for example, a motor.

  A ... motor, A1 ... motor, B ... motor, C ... motor, D ... motor, E ... motor, F ... motor, 1 ... motor housing, 1f ... Motor housing, 11 ... Outer wall part, 12 ... Inner wall part, 13 ... Flange part, 14 ... First elastic member, 15 ... Second elastic member, 2 ... Stator , 21 ... Stator core, 22 ... Insulator, 23 ... Coil, 3 ... Rotor, 31 ... Shaft, 32 ... Rotor holder, 33 ... Boss part, 34 ... Top surface part , 35, magnet, 41, first bearing, 411, outer ring, 412, inner ring, 413, ball, 42, second bearing, 421, outer ring, 422,. -Inner ring, 423 ... Ball, 42b ... Second bearing, 421b ... Ring, 422b ... Inner ring, 423b ... Ball, 42d ... Second bearing, 421d ... Outer ring, 422d ... Inner ring, 423d ... Ball, 42e ... Second bearing, 421e .... Outer ring, 422e ... Inner ring, 423e ... Ball, 5 ... Bearing housing, 51 ... Fixed part, 511 ... End face part, 52 ... Bearing holding part, 521 ... Circle Ring part, 522 ... Stepped part, 5b ... Bearing housing, 52b ... Bearing holding part, 5c ... Bearing housing, 52c ... Bearing holding part, 5d ... Bearing housing, 51d・ Fixed part, 52d ... Bearing holding part, 5e ... Bearing housing, 51e ... Fixing part, 52e ... Bearing holding part

An exemplary motor of the present invention includes a motor housing in which at least a part of a stator is accommodated, a rotor including a shaft that is a rotating shaft, and a first bearing and a second bearing that rotatably support the shaft. The motor housing has an outer wall portion that is disposed radially outside the stator and extends in the axial direction, and a flange that extends radially inward from an outer edge portion on one axial side of the outer wall portion. and parts, has, an inner wall portion Ru extending axially from at least a portion of the inner edge of the radially inner side of the flange portion, said inner wall portion, Ru extends at least partially in the axial direction and bearings housing is fixed, an inner ring of said first bearing and said second bearing, said being secured to the shaft, the outer ring of the first bearing is fixed to the inner surface of the inner wall portion, the second bearing Outer ring Characterized in that it is fixed to the inner surface of the bearing housing.

The bearing housing 5e shown in FIG. 7 has a cylindrical shape . In other words, the outer peripheral surface of the bearing housing 5e has the same outer diameter at all portions in the axial direction. In addition, the inner peripheral surface of the bearing housing 5e has the same outer diameter in all axial portions. In the bearing housing 5 e, the left end fixing portion 51 e is fixed to the outer peripheral surface of the inner wall portion 12. The inner wall portion 12 is press-fitted into the inner peripheral surface of the fixed portion 51e. The fixing of the inner wall portion 12 and the fixing portion 51e is not limited to press-fitting. For example, adhesion, welding, screwing, or the like may be used.

Claims (11)

A motor housing containing at least a part of the stator;
A rotor including a shaft that is a rotating shaft;
A motor having a first bearing and a second bearing for rotatably supporting the shaft,
The motor housing is
A cylindrical outer wall portion that is disposed radially outside the stator and extends in the axial direction;
A flange portion extending radially inward from an outer edge portion on one axial side of the outer wall portion;
A cylindrical inner wall extending in the axial direction from at least a portion of the radially inner inner edge of the flange,
A cylindrical bearing housing extending in the axial direction is fixed to the inner wall portion,
Inner rings of the first bearing and the second bearing are fixed to the shaft,
The motor according to claim 1, wherein an outer ring of the first bearing is fixed to an inner surface of the inner wall portion, and an outer ring of the second bearing is fixed to an inner surface of the bearing housing.   The motor according to claim 1, wherein at least a part of the inner wall portion overlaps the outer wall portion in a radial direction.   The motor according to claim 2, wherein an axial length of the outer wall portion is longer than an axial length of a portion of the inner wall portion that overlaps the outer wall portion in a radial direction.   The bearing housing includes: a fixed portion fixed to the inner wall portion at one end portion in the axial direction; and a bearing holding portion holding the second bearing at the other end portion. Item 4. The motor according to any one of Items 3 to 3.   The motor according to claim 4, wherein the fixing portion is disposed inside the inner wall portion.   The motor according to claim 5, wherein an outer diameter of an outer peripheral surface of the fixed portion is smaller than an outer diameter of another portion of the bearing housing. The fixed portion has an end surface portion that includes a through hole that extends radially inward from the axial tip of the fixed portion and penetrates in the axial direction around the rotation axis.
The motor according to claim 5, wherein the shaft passes through the through hole.   The motor according to claim 7, further comprising a first elastic member that contacts the end surface portion and an outer ring of the first bearing between the first bearing and the fixed portion.   The motor according to any one of claims 4 to 8, wherein an inner diameter of an inner peripheral surface of the bearing holding portion is larger than an inner diameter of another portion of the bearing housing. The bearing holding portion includes a stepped portion that is bent radially inward at an end portion on the fixed portion side,
10. The motor according to claim 9, further comprising a second elastic member between the second bearing and the stepped portion that contacts the stepped portion and the outer ring of the second bearing.   11. The motor according to claim 9, wherein an end of the bearing holding portion in the axial direction includes an annular portion that extends radially outward from the end of the axial direction.

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