WO2018146971A1

WO2018146971A1 - Motor and fan

Info

Publication number: WO2018146971A1
Application number: PCT/JP2017/046868
Authority: WO
Inventors: 祥平大菅; 隆宏檜皮; 陽平宮田
Original assignee: 日本電産株式会社
Priority date: 2017-02-09
Filing date: 2017-12-27
Publication date: 2018-08-16
Also published as: JPWO2018146971A1

Abstract

Provided is a motor comprising a rotor, a permanent magnet, a brush card assembly, a back cover, and a housing. The rotor has a core fixed to a shaft, a coil for exciting the core, and a commutator electrically connected to the coil. The brush card assembly has a plurality of brushes, a brush card that supports the plurality of brushes, and an outer peripheral wall that is provided on the outer periphery of the brush card and has a wall shape that protrudes in the axial direction. In an X-axis perpendicular to the central axis and a Y-axis perpendicular to both the central axis and the X-axis, the center of gravity of the plurality of brushes is located on one side with respect to the Y-axis. The outer peripheral wall has, on the one side with respect to the Y-axis, a notch part in which at least a portion of the outer peripheral is discontinuous, and is continuous in the other side.

Description

Motor and fan

The present invention relates to a motor and a fan.

2. Description of the Related Art Conventionally, a DC machine having a brush holder that holds a brush and other components described in Patent Document 1 is known.

Special table 2011-504719

In the DC machine having the brush holder of the conventional configuration, the brush holder that holds the brush vibrates due to repeated contact between the brush and the commutator during rotation, and noise may occur.

An object of the present invention is to suppress the vibration of the brush card assembly that holds the brush when the motor rotates.

An exemplary first invention of the present invention provides a rotor having a shaft centered on a central axis extending in the axial direction, a permanent magnet positioned radially outside the rotor, and supplying power to the rotor. A motor comprising: a brush card assembly; a back cover that supports the brush card assembly; and a housing that houses the brush card assembly, the rotor, and the permanent magnet together with the back cover. The rotor includes a core fixed to the shaft, a coil that excites the core, and a commutator that is electrically connected to the coil. The brush card assembly includes a plurality of brushes, a brush card that supports the plurality of brushes, and a wall-shaped outer peripheral wall that is provided on the outer periphery of the brush card and protrudes in the axial direction. In the X axis orthogonal to the central axis, and the Y axis orthogonal to the central axis and the X axis, the center of gravity of the plurality of brushes is located on one side with respect to the Y axis, and the outer peripheral wall extends to the Y axis. On the other hand, at least one part has a notch part which becomes discontinuous on the one side and is continuous on the other side.

According to the exemplary rotor of the first invention of the present invention, the center of gravity of the plurality of brushes is located on one side where the centers of gravity of the plurality of brushes are located with respect to the Y axis. The rigidity on the side is lower than the rigidity on the opposite side. Thereby, the position of the center of gravity of the plurality of brushes and the antinode of vibration of the brush card assembly can be brought close to each other, and the configuration of suppressing the vibration of the brush card assembly can be achieved. As a result, the vibration at the time of rotation in the motor which has the said brush card assembly can be suppressed.

FIG. 1 is a cross-sectional view of a motor. FIG. 2 is a perspective view of the motor as viewed from the upper surface side of the housing. FIG. 3 is a perspective view of the motor viewed from the bottom side of the back cover. FIG. 4 is a diagram illustrating the motor with the housing and the permanent magnet removed. FIG. 5 is a view showing the back cover and the brush card assembly. FIG. 6 is a perspective view of the brush card assembly. FIG. 7 is a plan view of the brush card assembly. FIG. 8 is a plan view of the brush card assembly as seen from the bottom side. FIG. 9 is a conceptual diagram showing the positions of the objects O1 and O2 and the center of gravity G.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiment described below is merely an example of the present invention, and does not limit the technical scope of the present invention. In addition, in each drawing, the same code | symbol is attached | subjected to the same component and the description may be abbreviate | omitted.

In this specification, “upper side” or “front side”, and “lower side” or “rear side” are defined for convenience with respect to the central axis J of the rotation of the motor. In addition, the upper surface of each component such as the rotor unit may be referred to as an “upper surface” and the lower surface may be referred to as a “bottom surface”.

In this specification, a horizontal plane with respect to the direction in which the central axis J extends is referred to as an XY plane having an X axis and a Y axis. For convenience of description of the drawings, one side with respect to the X axis is referred to as the upper side, the other side is referred to as the lower side, one side with respect to the Y axis is referred to as the left side, and the other side is referred to as the right side.

In addition, in this specification, the term “extend in the axial direction” means that it extends in a direction tilted in a range of less than 45 degrees with respect to the axial direction, in addition to the case where it extends in the axial direction strictly parallel to the central axis J. Including cases. Similarly, extending in the radial direction means not only extending in a direction strictly perpendicular to the central axis J but also extending in a direction inclined by less than 45 degrees from the direction perpendicular to the central axis. including.

<1. Embodiment>
The motor 1 of the present embodiment is a motor that is used to rotate an engine cooling fan. As shown in FIG. 1, the motor 1 of the present embodiment is arranged such that the central axis J extends in a direction perpendicular to the direction of gravity, but is not limited to such an arrangement. That is, the central axis J has a predetermined angle with respect to the direction of gravity.

FIG. 1 is a cross-sectional view of the motor 1 of the present embodiment. As shown in FIG. 1, the motor 1 of this embodiment includes a housing 10, a rotor 20, a brush card assembly 30, a permanent magnet 40, a front side bearing 41, and a rear side bearing 42. An impeller (not shown) is attached to the shaft 21 of the rotor 20 of the motor 1 used as a fan. Note that the output end side of the shaft 21 on the right side in FIG. 1 to which the impeller is attached is referred to as a front side or an upper side, and the left side in FIG. 1 is referred to as a rear side or a lower side.

<Case 10>
2 and 3 are external perspective views of the motor 1. 2 is a view of the motor 1 as viewed from the upper surface side of the housing 11, and FIG. 3 is a view of the motor 1 as viewed from the bottom surface side of the back cover 12. As shown in FIGS. 1 to 3, the housing 10 includes a housing 11 and a back cover 12. The housing 10 houses the rotor 20, the brush card assembly 30, the permanent magnet 40, the front side bearing 41, and the rear side bearing 42. Note that “accommodating” includes both the case where the entire object to be stored is located inside the stored object and the case where a part of the object to be stored is positioned inside the stored object.

<Housing 11>
The housing 11 is located on the front side of the back cover 12. The housing 11 includes a housing cylindrical portion 13, a housing upper surface portion 14, and a flange portion 15. The housing 11 is a conductive member such as metal.

The housing cylindrical portion 13 has a cylindrical shape concentric with the central axis J. The housing cylindrical portion 13 has a cylindrical shape extending in the axial direction from the outer periphery of the housing upper surface portion 14 toward the rear side. The housing cylindrical portion 13 surrounds the outer side in the radial direction of the rotor 20 and the permanent magnet 40. A permanent magnet 40 is fixed to the inner surface of the housing cylindrical portion 13.

The housing upper surface portion 14 is coupled to the front end portion of the housing cylindrical portion 13. The housing upper surface portion 14 has a disk shape concentric with the central axis J. The housing upper surface portion 14 has a plurality of upper surface side hole portions 14a penetrating the housing upper surface portion 14 in the axial direction. The upper surface side hole portion 14a has, for example, a circular shape. The upper surface side hole portions 14a are arranged at equal intervals along the circumferential direction around the central axis J.

The flange portion 15 extends radially outward from the rear end portion of the housing cylindrical portion 13. The motor 1 is attached to the engine cooling fan device via the flange portion 15.

The housing cylindrical portion 13 of the housing 11 is connected to the back cover cylindrical portion 16 of the back cover 12 by caulking.

<Back cover 12>
The back cover 12 is located on the rear side of the housing 11. The back cover 12 includes a back cover cylindrical portion 16 and a back cover bottom surface portion 17. The back cover 12 is a conductive member such as metal.

The back cover cylindrical portion 16 has a cylindrical shape concentric with the central axis J. The back cover cylindrical portion 16 has a cylindrical shape extending in the axial direction from the outer periphery of the back cover bottom surface portion 17 toward the front side. The back cover cylindrical portion 16 surrounds the outer side in the radial direction of the rotor 20 and the brush card assembly 30. A brush card assembly 30 is disposed on the inner surface of the back cover cylindrical portion 16. As shown in FIG. 2, the back cover cylindrical portion 16 has a protruding portion 16 a that protrudes radially outward.

The back cover bottom surface portion 17 is connected to the rear end portion of the back cover cylindrical portion 16. The back cover bottom surface portion 17 has a disk shape concentric with the central axis J. The back cover bottom surface portion 17 has a plurality of bottom surface side hole portions 17a penetrating the back cover bottom surface portion 17 in the axial direction. The bottom surface side hole portion 17a has, for example, a long hole shape extending in the circumferential direction. The bottom surface side hole portion 17a is provided in an arbitrary number of 1 or more, but may be omitted. The back cover bottom surface portion 17 has a plurality of convex portions 17b extending radially in the radial direction. The convex portion 17b protrudes from the back cover bottom surface portion 17, and has a shape protruding from the rear side toward the front side.

<Rotor 20>
FIG. 4 is a view showing the motor 1 with the housing 11 and the permanent magnet 40 removed. As shown in FIGS. 1 and 4, the rotor 20 includes a shaft 21, a core 22, a coil 23, and a commutator 25.

The shaft 21 extends in a cylindrical shape in the axial direction around the central axis J. The front end portion of the shaft 21 is exposed to the outside on the front side of the housing 11. A fan is connected to the front end of the shaft 21.

The core 22 is fixed to the shaft 21. The core 22 is located on the radially inner side of the housing 11. The core 22 faces the permanent magnet 40 in the radial direction. The core 22 includes a core back and a plurality of tooth portions. The plurality of tooth portions are arranged at equal intervals along the circumferential direction.

The coil 23 excites the core 22 by energization. The coil 23 is wound around the tooth portion of the core 22 through an insulator having an insulating property. For example, the coil 23 is wound around the core 22 by concentrated winding.

The commutator 25 is located on the rear side of the core 22. The commutator 25 includes an insulating member 25a and a plurality of segments 25b.

The insulating member 25a is an insulating member. The insulating member 25a has, for example, a cylindrical shape that surrounds the radially outer side of the shaft 21. The insulating member 25 a is fitted on the outer peripheral surface of the shaft 21.

The plurality of segments 25b are fixed to the outer surface of the insulating member 25a. The plurality of segments 25b are arranged at equal intervals along the circumferential direction. Each of the plurality of segments 25b is a conductor that extends in the axial direction. The segment 25b is electrically connected to the coil 23. The radially outer surface of the segment 25b can contact brushes 51a to 51d described later. The segment 25b in contact with the brushes 51a to 51d changes as the rotor 20 rotates. That is, the commutator 25 is electrically connected to the coil 23.

<Permanent magnet 40>
The permanent magnet 40 is fixed inside the housing 11. The permanent magnet 40 is located on the radially outer side of the rotor 20 and is disposed so as to face the rotor 20. The permanent magnet 40 has, for example, an arc shape extending in the circumferential direction. For example, four permanent magnets 40 are provided along the circumferential direction. The permanent magnet 40 has two magnetic poles at one end and the other end in the circumferential direction. That is, the number of magnetic poles of the permanent magnet 40 is eight. However, the number of magnetic poles of the permanent magnet 40 can be arbitrarily changed.

<Front side bearing 41 and rear side bearing 42>
The front side bearing 41 and the rear side bearing 42 support the shaft 21. The front bearing 41 is located on the front side of the core 22. The front bearing 41 is held by the housing 11. The rear side bearing 42 supports the end of the shaft 21 on the rear side of the commutator 25. The rear side bearing 42 is held by the back cover 12.

<Brush card assembly 30>
The brush card assembly 30 is located on the rear side of the core 22 of the rotor 20. The brush card assembly 30 is disposed in the back cover 12. The brush card assembly 30 supplies current to the rotor 20 through the commutator 25.

FIG. 5 is a perspective view of the back cover 12 and the brush card assembly 30 as viewed from the front side. FIG. 6 is a perspective view of the brush card assembly 30 as viewed from the front side. FIG. 7 is a plan view of the brush card assembly 30 as viewed from the front side. 6 and 7 omit the electronic components and the like for convenience of explanation. 6 and 7 show an X axis and a Y axis perpendicular to the central axis J.

The brush card assembly 30 includes a brush card 31, brush units 50a to 50d, and choke

coils

61 and 62. The brush units 50a to 50d have brushes 51a to 51d, respectively.

<Brush card 31>
The brush card 31 has a plate part 70 and a resin part 32. The brush card 31 is formed by insert molding in which the plate portion 70 is inserted into a mold. The brush units 50a to 50d and the choke coils 61 and 62 are attached to the brush card 31. The brush card 31 can also be configured by fixing the plate portion 70 to the resin portion 32 by caulking.

<Plate part 70>
The plate portion 70 is formed of a conductive member such as brass or copper. The plate part 70 is electrically connected to components including the choke coils 61 and 62 to constitute a circuit. The plate unit 70 supplies current to the rotor 20. The plate portion 70 includes a positive electrode side connection terminal 71a, a negative electrode side connection terminal 71b, brush unit installation portions 72a to 72d, and clamping portions 75 to 77. In the plate part 70, parts connected to other components are exposed to the outside, and other parts are covered with resin.

The positive electrode side connection terminal 71 a is connected to the choke coil 61. The choke coil 61 is, for example, a choke coil with a fuse having a fuse 61a. With the configuration having the choke coil 61, noise included in the supplied power can be reduced. Further, when an overcurrent is about to flow due to a short circuit of a part of the electric circuit, it is possible to prevent the fuse 61a from operating and causing an abnormal current to circulate to the power supply side. The negative electrode side connection terminal 71 b is connected to the choke coil 62.

Brush units 50a to 50d are installed in the brush unit installation sections 72a to 72d, respectively. The brush unit installation parts 72a to 72d themselves do not constitute a circuit. Pigtails extending from the brushes 51a to 51d in the brush units 50a to 50d are electrically connected to the plate portions 70 constituting the circuit, respectively.

The sandwiching portions 75 to 77 are plate-like members extending radially outward from the outer peripheral position of the plate portion 70. The sandwiching portions 75 to 77 are grounded via capacitors. As shown in FIGS. 6 and 7, the three sandwiching portions 75 to 77 are located on the left side of the plate portion 70 opposite to the right side on which the connector portion 35 is disposed with respect to the Y axis.

The clamping portions 75 to 77 are located between the housing 11 and the back cover 12 in the axial direction. The sandwiching portions 75 to 77 are sandwiched in the axial direction by the housing 11 and the back cover 12. As a result, the brush card assembly 30 is held by holding the holding portions 75 to 77 between the housing 11 and the back cover 12. Further, the housing 11 and the back cover 12 are caulked while sandwiching the sandwiching portions 75 to 77. The sandwiching portions 75 to 77 are at the ground potential as described above, but are electrically connected by being sandwiched between the conductive housing 11 and the back cover 12 so that the ground potential can be stabilized. . Note that the ground potential is also referred to as a reference potential.

<Resin part 32>
The resin part 32 is a resin part that covers a predetermined part of the plate part 70. The resin part 32 includes a brush card cylinder part 33, a brush card bottom part 34, and a connector part 35.

<Brush card cylinder part 33>
The brush card cylinder portion 33 has a cylindrical shape partially cut away. The brush card cylinder portion 33 has a wall shape protruding in the axial direction from the outer periphery of the brush card bottom surface portion 34. The brush card cylinder part 33 has a connector outer peripheral wall 33a, a brush outer peripheral wall 33b,

notches

33d and 33e,

first ribs

33f and 33g, and a brush card concave part 33h. The connector outer peripheral wall 33a and the brush outer peripheral wall 33b are collectively referred to as an outer peripheral wall. The outer peripheral wall of the brush card cylinder part 33 opposes the inner peripheral wall of the back cover cylindrical part 16 via a gap. That is, a gap through which gas and liquid can flow is provided between the outer peripheral wall of the brush card cylinder 33 and the back cover cylinder 16. A gap between the outer peripheral wall of the brush card cylinder 33 and the back cover cylinder 16 communicates with the flow hole F. When the housing 11 and the back cover 12 are combined, the flow hole F is an opening part of the back cover 12 that is opened by the protrusion 16.

The connector outer peripheral wall 33 a is a part of the outer peripheral wall of the brush card cylinder portion 33 connected to the connector portion 35. The connector outer peripheral wall 33a is disposed on the right side with respect to the Y axis. The connector outer peripheral wall 33a is longer in the axial direction than the brush outer peripheral wall 33b.

The brush outer peripheral wall 33b is a part of the outer peripheral wall of the brush card cylinder portion 33 and is located on the radially outer side of the brush units 50a to 50d. The brush outer peripheral wall 33b has

notches

33d and 33e on the left side with respect to the Y axis. The

notches

33d and 33e are portions where the axial length is shorter than other portions of the brush outer peripheral wall 33b. In other words, the

notches

33d and 33e are portions that are notched in the axial direction with respect to other portions of the brush outer peripheral wall 33b. That is, the outer peripheral wall composed of the connector outer peripheral wall 33a and the brush outer peripheral wall 33b is discontinuous at the two positions on the left side of the Y axis and is continuous on the right side of the Y axis by the

notches

33d and 33e. Therefore, as for the outer peripheral wall of the brush card cylinder part 33, the right side part of the Y-axis has high rigidity compared with the left side part of the Y-axis. That is, the rigidity on the right side of the Y axis of the brush card assembly 30 is higher than the rigidity on the left side of the Y axis.

The

notches

33d and 33e communicate with the gap between the outer peripheral wall of the brush card cylinder 33 and the back cover cylinder 16. For this reason, the space inside the brush card assembly 30 extends from the through hole F to the outside of the motor 1 through the gaps between the

cutout portions

33d and 33e and the outer peripheral wall of the brush card tube portion 33 and the back cover cylinder portion 16. Communicate with space. As a result, the flowability of the gas inside and outside the brush card assembly 30 is improved, and the inside of the motor, in particular, the vicinity of the brush card assembly 30 is cooled.

The

first ribs

33f and 33g are located on the right side with respect to the Y axis. The

first ribs

33f and 33g are provided on the inner peripheral side of the brush outer peripheral wall 33b, and connect the inner peripheral surface of the brush outer peripheral wall 33b and the brush card bottom surface portion 34. The

first ribs

33f and 33g have the same height as the brush outer peripheral wall 33b and extend from the brush card bottom surface 34 in the axial direction. As for the

1st ribs

33f and 33g, the one end part which contact | connects the brush card bottom face part 34 is extended in the radial direction with respect to the other end part. The first rib 33f is disposed at a position closer to the connector part 35 than the brush unit installation part 72a in the circumferential direction. The first rib 33g is disposed at a position closer to the connector part 35 than the brush unit installation part 72d in the circumferential direction. The

first ribs

33f and 33g support the brush outer peripheral wall 33b against the stress that the brush outer peripheral wall 33b tends to fall. Thereby, the shape of the brush outer peripheral wall 33b is maintained, and the rigidity of the right portion of the brush card 31 with respect to the Y axis is increased. That is, the rigidity on the right side of the Y axis of the brush card assembly 30 is higher than the rigidity on the left side of the Y axis.

The brush outer peripheral wall 33b has a brush card recess 33h that is recessed radially inward. As shown in FIGS. 4 and 5, the brush card recess 33 h faces the protruding portion 16 a of the back cover 12 in the radial direction. Therefore, since the circulation hole F communicates with a larger gap by the brush card recess 33h and the protrusion 16a, the air circulation inside and outside the circulation hole F is good. Since the flow hole F is located not in the rotational axis direction of the motor 1 but in the radial position, when the central axis is configured to have a predetermined angle with respect to the gravity direction, it is on the lower side in the gravity direction. . Therefore, when liquid is present inside the brush card assembly 30, the liquid accumulates in the protruding portion 16 a by its own weight and is discharged from the circulation hole F to the outside of the motor 1.

<Brush card bottom 34>
The brush card bottom surface portion 34 holds the bottom surface portion of the plate portion 70. The brush card bottom surface portion 34 has an annular shape having a circular opening 36 centered on the central axis J. The brush card bottom surface portion 34 has a substantially annular shape centered on the central axis J. The commutator 25 is located inside the brush card bottom surface 34. The brush card bottom surface portion 34 faces the back cover bottom surface portion 17 through a gap.

The brush card bottom portion 34 holds brush units 50a to 50d including the brushes 51a to 51d and parts including the choke coils 61 and 62.

The brush card bottom part 34 has a plurality of through holes 34a. The plurality of through holes 34a penetrate the brush card bottom surface portion 34 in the axial direction. The through hole 34a allows air to flow in and out of the brush card bottom surface 34, and the brush card assembly 30 is cooled. The region of the through hole 34a viewed in the XY plane is wider on the left side than the Y axis and on the right side than the Y axis. Therefore, due to the through hole 34a, the rigidity on the right side of the Y axis of the brush card assembly 30 is higher than the rigidity on the left side of the Y axis.

As shown in FIGS. 6 and 7, the brush card bottom surface portion 34 has bottom surface ribs 34b to 34e at positions close to the connector portion 35 on the right side of the Y axis. The bottom ribs 34b to 34e extend in the axial direction from the brush card bottom portion 34 toward the front side.

The bottom rib 34d corresponds to the second rib of the present invention. The bottom rib 34c corresponds to the third rib of the present invention. The bottom rib 34b corresponds to the fourth rib of the present invention. The bottom ribs 34b to 34e are provided on the surface with the brush, but may be provided on the opposite surface.

In a plan view on the XY plane, the bottom rib 34b extends in the radial direction from the outer periphery of the opening 36 along the X axis. The bottom rib 34b increases the rigidity of the brush card 31 by acting so that the right side from the Y axis in the brush card bottom surface portion 34 acts against a stress to bend by bending a straight line parallel to the Y axis.

The bottom rib 34b is located between the positive electrode side connection terminal 71a and the negative electrode side connection terminal 71b. The bottom rib 34b is used as a member for increasing rigidity, and at the same time, since it is an insulator formed of a resin, the positive electrode side connection terminal 71a and the negative electrode side connection terminal 71b are prevented from contacting and short-circuiting. Can do. In particular, in the motor 1 of the present embodiment, metal powder generated from the brushes 51a to 51d due to friction with the commutator 25 may accumulate in the vicinity of the positive electrode side connection terminal 71a and the negative electrode side connection terminal 71b. However, even when the metal powder is deposited in this way, the bottom ribs 34b can improve the insulation between the positive electrode side connection terminal 71a and the negative electrode side connection terminal 71b.

The bottom rib 34 c extends obliquely with respect to the X axis from the middle position of the bottom rib 34 b and extends toward the connector outer peripheral wall 33 a of the brush card cylinder portion 33. The bottom rib 34c on the upper side of the X-axis is against the stress that the right side of the Y-axis and the upper side of the X-axis of the brush card bottom section 34 is opposed to the stress to bend by bending a straight line perpendicular to the direction in which the bottom rib 34c extends. By acting on, the rigidity of the brush card 31 is increased. Similarly, the bottom rib 34c on the lower side of the X axis tends to bend by bending a straight line perpendicular to the direction in which the bottom rib 34c extends on the right side of the Y axis in the brush card bottom portion 34 and below the X axis. By acting against the stress, the rigidity of the brush card 31 is increased. The bottom rib 34c is longer in the axial direction than the brush outer peripheral wall 33b, and comes into contact with the connector outer peripheral wall 33a having high rigidity because it is close to the connector portion 35, so that the rigidity of the installation portion can be more effectively increased. Can do.

The bottom rib 34d extends across the brush card cylinder 33 perpendicular to the X axis. That is, the bottom rib 34d extends in a direction horizontal to the Y axis. The bottom rib 34d acts so that the right side of the bottom surface portion 34 of the brush card 34 against the stress to bend by bending a straight line parallel to the X axis against the Y axis increases the rigidity of the brush card 31.

The bottom rib 34e extends in a direction horizontal to the X axis from the position where the

bottom ribs

34c and 34d intersect. The bottom rib 34e is disposed at a position near the end of the connector portion 35 in the Y-axis direction. The bottom rib 34e supports the connector outer peripheral wall 33a against the stress that the connector outer peripheral wall 33a tends to fall. Thereby, the shape of the connector outer peripheral wall 33a is maintained, and the rigidity of the brush card 31 near the connector portion 35 is increased.

These bottom ribs 34b to 34e are partially crossed, so that the falling of the intersecting bottom ribs 34b to 34e can be suppressed. As a result, the rigidity of the brush card 31 by the individual bottom ribs 34b to 34e can be further increased.

Also, the bottom ribs 34b to 34e are connected at one end to the connector outer peripheral wall 33a, the brush outer peripheral wall 33b, and the brush card inner peripheral wall 36b, thereby preventing the wall portions from collapsing. Thereby, the rigidity of the brush card 31 by these wall parts can be improved more.

These bottom ribs 34b to 34e make the rigidity on the right side of the Y axis of the brush card assembly 30 higher than the rigidity on the left side of the Y axis. Note that the rib for increasing the rigidity on the right side of the Y axis of the brush card assembly 30 does not necessarily include the bottom ribs 34b to 34e, and may include a part of the bottom ribs 34b to 34e. Since the bottom ribs 34b to 34e are disposed on the same surface as the surface on which the brushes 51a to 51d that cause the vibration of the brush card 31 are disposed, the vibration of the brush card 31 can be effectively suppressed.

<Brush card inner

peripheral wall

36a, 36b>
The brush card inner

peripheral walls

36 a and 36 b are located at a part of the outer periphery of the opening 36 of the brush card bottom surface 34. The brush card inner

peripheral walls

36 a and 36 b extend in the axial direction from the inner edge of the brush card bottom surface portion 34. Since the brush card inner peripheral wall 36b disposed on the right side with respect to the Y axis is connected to the bottom rib 34b, the rigidity on the right side of the Y axis can be increased.

<Connector part 35>
The connector part 35 is connected to the outer surface in the radial direction of the connector outer peripheral wall 33a on the right side of the Y axis. The connector part 35 is disposed between the

brushes

51a and 51d disposed on the right side of the Y axis. The connector part 35 extends radially outward along the X axis. Although illustration is omitted, the connector part 35 has a cylindrical shape opening outward in the radial direction. Inside the connector portion 35, the radially outer end of the positive electrode side connection terminal 71a and the radially outer end of the negative electrode side connection terminal 71b are exposed. The positive electrode side connection terminal 71 a and the negative electrode side connection terminal 71 b are electrically connected to an external power source through the inside of the connector portion 35. That is, the connector unit 35 receives power from the outside and supplies driving power to the motor 1 via the positive electrode side connection terminal 71a and the negative electrode side connection terminal 71b.

Since the connector part 35 is located on the right side of the Y axis, the rigidity of the outer peripheral wall of the brush card cylinder part 33 on the right side of the Y axis can be increased.

<Brush units 50a to 50d>
The brush unit 50a includes a brush 51a, a box-shaped brush case 50a2 that accommodates the brush 51a and extends in the radial direction, and a coil spring 50a3 accommodated in the brush case 50a2. The brush case 50a2 is formed by bending a metal plate, and a bottom surface and a radially inner side surface are opened. The coil spring 50a3 is interposed between the radially outer side surface of the brush case 50a2 and the radially outer side surface of the brush 51a, and elastically presses the brush 51a radially inward. The other brush units 50b to 50d have the same configuration. The brush units 50a to 50d are installed on the brush unit installation parts 72a to 72d. As a result, the brushes 51a to 51d are elastically pressed radially inward in the respective brush cases 50a2, and are accommodated so as to be movable in the radial direction. The brushes 51a to 51d come into contact with the commutator 25 that is radially inward while applying a radially inward biasing force. The brush 51a is connected to a pigtail 51a1 made of a mesh line for conducting the brush 51a. The pigtail 51a1 is pulled out through the slit on the top surface of the brush case 50a2, and is electrically connected to the plate portion 70 constituting the circuit.

Further, as shown in FIG. 7, the brush unit installation portion 72a and the brush unit 50a are arranged on the right side of the Y axis so as to form approximately 67.5 degrees with respect to the X axis (A). The brush unit installation part 72b and the brush unit 50b are arranged on the left side of the Y axis so as to form approximately 22.5 degrees with respect to the X axis (B). The brush unit installation part 72c and the brush unit 50c are arranged on the left side of the Y axis so as to form approximately 22.5 degrees with respect to the X axis in the direction opposite to the brush unit 50b (C). The brush unit installation part 72d and the brush unit 50d are arranged on the right side of the Y axis so as to form approximately 67.5 degrees with respect to the X axis in the direction opposite to the brush unit 50a (D).

<Lattice-like ribs 34f>
FIG. 8 is a plan view of the brush card assembly 30 as viewed from the bottom side. The brush card bottom surface portion 34 has a grid-like rib 34f on the bottom side, which has a grid shape extending in a plurality of directions in the horizontal direction to the X-axis and the horizontal direction to the Y-axis. Have. That is, on the bottom surface 34 of the brush card, lattice ribs 34f are disposed on the surface opposite to the surface on which the brushes 51a to 51d are disposed and facing the back cover bottom surface portion 17 in order to increase rigidity. The

Note that the lattice-like ribs 34f do not necessarily have to have a plurality of shapes extending in a direction horizontal to the X axis and a direction horizontal to the Y axis. For example, an arbitrary lattice shape may be employed in which the shape surrounded by the plurality of ribs is not a rectangle but a polygon or a circle, and the plurality of ribs are arranged in a stripe shape. Further, instead of arranging the grid-like ribs 34f, the thickness of the resin of the brush card bottom surface portion 34 on the right side with respect to the Y axis may be increased. However, if the thickness of a part of the brush card bottom surface portion 34 is increased, the cost may be increased, or deformation such as sink marks may occur in the resin. preferable. Further, the lattice-like ribs 34f may be provided on the surface on which the brushes 51a to 51d are disposed on the brush card bottom surface 34.

<The position of the center of gravity>
As will be described later, the positions of the centers of gravity of the brush units 50a to 50d are closely related to the vibration antinodes of the brush card 31, so the positions of the centers of gravity of the brush units 50a to 50d will be described here. Note that the positions of the centers of gravity of the brush units 50a to 50d are substantially the same as the positions of the centers of gravity of the brushes 51a to 51d.

First, the center of gravity G of the object O1 having the weight m1 and the object O2 having the weight m2 arranged on the straight line is determined by the following formula, where the distances from the reference point are x1 and x2, respectively. . Note that the distance of the center of gravity G from the reference point is XG.

FIG. 9 is a conceptual diagram showing the positions of the objects O1 and O2 and the center of gravity G. In the drawing, arrows extending from the objects O1 and O2 indicate vectors in the direction of gravity, and arrows extending from the center of gravity G indicate vectors given to the positions of the center of gravity supporting the objects O1 and O2. In the above formula, the gravity acceleration g is omitted. Thus, the centers of gravity of the objects O1 and O2 are G positions.

Next, when n objects having respective weights m1, m2,... Mn are arranged on the XY plane, the centroids of these n objects are determined by the following equation. The Each object is arranged at a position of (x1, y1), (x2, y2),... (Xm, ym) with respect to the reference point, and the position of the center of gravity G is (xG, yG).

The gravity center position E of the brushes 51a to 51d derived from the above mathematical formula is the position E shown in FIG.

The brushes 51a to 51d have a shape extending in the radial direction. Strictly speaking, the radially inner surface in contact with the commutator 25 has an inclination, but has a shape close to a rectangular parallelepiped. Therefore, the positions of the centers of gravity of the brush units 50a to 50d are substantially equal to the center positions of the central portions of the brush units 50a to 50d when viewed on the XY plane. That is, when viewed on the XY plane, the center position of the central portion of the brush units 50a to 50d is the intersection of the straight line connecting the central portions of the

brushes

51a and 51c and the straight line connecting the central portions of the

brushes

51b and 51d. Almost equal.

<Vibration belly position>
The brush card 31 holding the brush units 50a to 50d vibrates when the brushes 51a to 51d repeatedly contact the commutator 25 when the motor 1 rotates. At this time, the brush card 31 has a “vibration antinode” that becomes the center of vibration in the axial direction when the motor 1 rotates. According to the examination results of the inventors, it is found that the vibration of the brush card 31 during the rotation of the motor 1 can be effectively suppressed by making the center of gravity of the brushes 51a to 51d close to the vibration antinode. ing.

The vibration belly is mainly determined by the rigidity of each part of the brush card 31. As described above, in the brush card 31, the balance of the rigidity on the right and left sides of the Y-axis is adjusted by the configuration of the brush card cylinder portion 33 that is the outer peripheral wall and the brush card bottom surface portion 34 that is the flat portion. . Since the brush card 31 is configured to be substantially line symmetric with respect to the X axis, the positions of the centers of gravity of the brushes 51a to 51d and the positions of the vibration antinodes are all positions on the X axis.

In the brush card 31, since the brushes 51a to 51d are arranged on the left side of the Y axis, the centers of gravity of the brushes 51a to 51d are located on the left side of the Y axis. On the other hand, in the brush card 31 of the conventional configuration, the outer peripheral wall of the brush card cylinder portion 33 is continuous without considering the vibration antinode, so that the vibration antinode is substantially overlapped with the central axis J. It was. Therefore, the center of gravity of the brushes 51a to 51d is separated from the vibration belly of the brush card 31.

As described above, the brush card 31 according to the present embodiment employs a configuration in which the rigidity on the right side is increased while the rigidity on the left side is reduced with respect to the Y axis. On the left side. For example, on the left side with respect to the Y-axis, the outer peripheral wall of the brush card cylinder part 33 is not continuous due to the

notches

33d and 33e, so that the rigidity on the left side of the Y-axis of the brush card 31 is relatively low. It is low. On the other hand, since the outer peripheral wall of the brush card cylinder part 33 is continuous on the right side with respect to the Y axis, the rigidity on the left side of the Y axis of the brush card 31 is relatively high.

Further, on the right side with respect to the Y axis, the brush card 31 has the

first ribs

33f and 33g, the bottom ribs 34b to 34e, and the lattice ribs 34f, so that the rigidity is enhanced. Accordingly, the balance of rigidity in the brush card 31 is adjusted, and the vibration antinode of the brush card 31 is located on the left side with respect to the Y axis and overlaps or is close to the center of gravity of the brushes 51a to 51d. Therefore, the motor 1 having the brush card 31 can suppress vibration during rotation.

In the brush card 31, the amount of resin used is heavier on the right side with respect to the Y axis than on the left side with respect to the Y axis. It is close. It is to be noted that the same effect can be obtained even when the amount of resin used is equal and the weight of the plate portion 70 is heavier on the right side with respect to the Y axis.

In addition, the brush card 31 and the back cover 12 are opposed to each other with a gap therebetween, and the brush card 31 has the through holes 34a and the

notches

33d and 33e, so that air can easily flow inside and outside the brush card 31. is there. Thereby, in the motor 1 of this embodiment, a vibration can be suppressed, maintaining the cooling property of the brush card assembly 30. FIG.

In addition, the motor 1 of the present embodiment includes a configuration in which the rigidity of the brush card 31 is adjusted and the position of the vibration antinode is in the vicinity of the center of gravity in addition to the configuration summarized here.

<2. Modification>
The motor of the present invention is not limited to the above embodiment, and includes various forms that can be considered from the above embodiment. For example, the motor of the present invention may have the following modified configuration. In addition, about the structure similar to the above-mentioned embodiment, the same name or reference code may be attached | subjected and the description may be abbreviate | omitted.

In the embodiment, various configurations for reducing the rigidity on the left side of the brush card 31 and increasing the rigidity on the right side are adopted so that the vibration of the brush card 31 is on the left side of the Y axis. It is not always necessary to have a configuration that includes all of them at the same time. For example, the brush card 31 does not have the

first ribs

33f and 33g, the bottom ribs 34b to 34e, and the grid-like ribs 34f, and the outer peripheral wall of the brush card cylinder part 33 is notched to the left side with respect to the Y axis. You may employ | adopt the structure which has 33e.

Further, the vibration belly of the brush card 31 and the center of gravity of the brushes 51a to 51d do not necessarily have to coincide with each other, and may be arranged in the vicinity. Further, since the brushes 51a to 51d are worn by contact with the commutator 25, the centers of gravity of the brushes 51a to 51d change with use of the motor. As a result, the relationship between the antinode of vibration of the brush card 31 and the center of gravity of the brushes 51a to 51d changes, so that the case where the effect of suppressing vibration is reduced may be considered. However, when the brushes 51a to 51d are worn, as the brushes 51a to 51d are shortened, the coil spring 50a3 is extended and the elastic force is reduced. Therefore, in this case, the urging force of the brushes 51a to 51d against the commutator 25 is smaller than the urging force before the brushes 51a to 51d are worn or when the wear amount is small. The force is weakened and the vibration of the brush card assembly 30 is reduced. Therefore, even when the wear amount is increased from the time when the brushes 51a to 51d are worn or when the wear amount is small, the result is a motor with little vibration.

<3. Other>
Heretofore, specific descriptions have been given of the embodiments and modifications of the present invention. In the above description, the description is merely an embodiment, and the scope of the present invention is not limited to this embodiment, but is broadly interpreted to the extent that a person skilled in the art can grasp. For example, the above embodiment and each modified example can be implemented in combination with each other.

The motor of the present invention is mainly used as a motor for an engine cooling fan of an automobile. The motor of the present invention is used for, for example, a brake motor or an electric power steering motor. Moreover, it can utilize for various uses besides the object for motor vehicles. For example, it may be used for an electric assist bicycle, an electric motorcycle, a home appliance, an OA device, a medical device, and the like.

The motor of the present invention can also constitute a generator with a similar structure. The motor of the present invention can also be used as a generator used in automobiles, electrically assisted bicycles, wind power generation, and the like.

The present invention can be used as, for example, a motor for an engine cooling fan of an automobile.

DESCRIPTION OF SYMBOLS 1 ... Motor 10 ... Housing | casing 11 ... Housing 12 ... Back cover 13 ... Housing cylindrical part 13a ... Housing through-hole 14 ... Housing upper surface part 14a ... Upper surface side hole part 15 ... Flange part 16 ... Back cover cylindrical part 16a ... Projection part 17 ... back cover bottom surface portion 17a ... bottom surface side hole portion 17b ... convex portion 20 ... rotor 21 ... shaft 22 ... core 23 ... coil 25 ... commutator 25a ... insulating member 25b ... segment 30 ... brush card assembly 31 ... brush card 32 ... Resin portion 33 ... Brush card tube portion 33a ... Connector outer peripheral wall 33b ... Brush outer

peripheral wall

33d, 33e ...

Notch portion

33f, 33g ... First rib 33h ... Brush card concave portion 33m ... Contact portion 33n ... Projection portion 34 ... Brush card bottom surface portion 34a ... through holes 34b to 34e ... bottom ribs 35 Connector part 36 ... Opening

part

36a, 36b ... Brush card inner peripheral wall 40 ... Permanent magnet 41 ... Front side bearing 42 ... Rear side bearing 50a-50d ... Brush unit 50a2 ... Brush case 50a3 ... Coil springs 51a-51d ... Brush 51a1 ... Pigtail 61 62 ... Choke coil 61a ... Fuse 70 ... Plate part 71a ... Positive electrode side connection terminal 71b ... Negative electrode side connection terminal 72a-72d ... Brush unit installation part 75-77 ... Clamping part

Claims

A rotor having a shaft around a central axis extending in the axial direction;
A permanent magnet located radially outside the rotor;
A brush card assembly for supplying power to the rotor;
A back cover for supporting the brush card assembly;
A housing for housing the brush card assembly, the rotor, and the permanent magnet together with the back cover;
The rotor is
A core fixed to the shaft;
A coil for exciting the core;
A commutator electrically connected to the coil,
The brush card assembly is
Multiple brushes,
A brush card for supporting the plurality of brushes;
A wall-shaped outer peripheral wall projecting in the axial direction, provided on the outer periphery of the brush card;
Have
In the X axis orthogonal to the central axis, and the Y axis orthogonal to the central axis and the X axis,
The center of gravity of the plurality of brushes is located on one side with respect to the Y axis,
The outer peripheral wall has a cutout portion at least partially discontinuous on the one side with respect to the Y axis, and is continuous on the other side.
motor.
In a continuous part of the outer peripheral wall, it has a first rib connecting the inner peripheral surface of the outer peripheral wall and the flat surface of the brush card.
The motor according to claim 1.
The back cover is opposed to the outer peripheral wall via a gap,
The gap communicates with the notch,
The motor according to claim 1 or 2.
A rotor having a shaft around a central axis extending in the axial direction;
A brush card assembly for supplying power to the rotor;
A back cover for supporting the brush card assembly;
A permanent magnet located radially outside the rotor;
A housing for housing the brush card assembly, the rotor, and the permanent magnet together with the back cover;
The rotor is
A core fixed to the shaft;
A coil for exciting the core;
A commutator electrically connected to the coil,
The brush card assembly is
Multiple brushes,
A brush card for supporting the plurality of brushes;
Have
In the X axis orthogonal to the central axis, and the Y axis orthogonal to the central axis and the X axis,
The center of gravity of the plurality of brushes is located on one side with respect to the Y axis,
The brush card has, on the other side, a rib extending to the outer periphery while intersecting with the X axis.
motor.
The rib is
A second rib extending perpendicular to the X axis;
A third rib extending obliquely intersecting the X axis,
The motor according to claim 4.
The rib is disposed on the same surface of the brush card as the surface on which the first brush, the second brush, the third brush, and the fourth brush are disposed.
The motor according to claim 4 or 5.
A rotor having a shaft around a central axis extending in the axial direction;
A brush card assembly for supplying power to the rotor;
A back cover for supporting the brush card assembly;
A permanent magnet located radially outside the rotor;
A housing for housing the brush card assembly, the rotor, and the permanent magnet together with the back cover;
The rotor is
A core fixed to the shaft;
A coil for exciting the core;
A commutator electrically connected to the coil,
The brush card assembly is
Multiple brushes,
A brush card for supporting the plurality of brushes;
Have
In the X axis orthogonal to the central axis, and the Y axis orthogonal to the central axis and the X axis,
The center of gravity of the plurality of brushes is located on one side with respect to the Y axis,
The brush card has a grid-like rib on a plane on the other side with respect to the Y axis.
motor.
The grid ribs are disposed on a surface of the brush card opposite to a surface on which the first brush, the second brush, the third brush, and the fourth brush are disposed.
The motor according to claim 7.
A connector portion that receives power from outside at a position between the third brush and the fourth brush in the circumferential direction;
The motor according to any one of claims 1 to 8.
The connector portion includes a first electrode line that supplies power of the first electrode, and a second electrode line that supplies power of the second electrode;
The brush card has a fourth rib between the first electrode line and the second electrode line.
The motor according to any one of claims 1 to 9.
In the brush card, the other side with respect to the Y axis is heavier than the one side.
The motor according to any one of claims 1 to 10.
The plurality of brushes are
A first brush and a second brush which are arranged on the one side with respect to the Y axis and arranged to form an angle of approximately 22.5 degrees in different directions with respect to the X axis;
A third brush and a fourth brush arranged on the other side with respect to the Y axis and arranged to form approximately 67.5 degrees in different directions with respect to the X axis,
The motor according to any one of claims 1 to 11.
The motor according to any one of claims 1 to 12,
An impeller coupled to the shaft;
Fan with.