CN111799957B

CN111799957B - Brush motor

Info

Publication number: CN111799957B
Application number: CN202010239988.2A
Authority: CN
Inventors: 胜田喜宣
Original assignee: Mabuchi Motor Co Ltd
Current assignee: Mabuchi Motor Co Ltd
Priority date: 2019-04-05
Filing date: 2020-03-30
Publication date: 2022-11-01
Anticipated expiration: 2040-03-30
Also published as: JP2020171177A; DE102020109238A1; JP7333190B2; CN111799957A

Abstract

The invention provides a brush motor which realizes the miniaturization of the brush motor. The brush motor is provided with: a rotor having a commutator; a brush holder (15) that holds a brush (16) in contact with the commutator; and a terminal connected to a power supply and supplying power to the brush (16), wherein the brush holder (15) is provided with: a brush arm (48) for urging the brush (16) toward the commutator; and a conductor (47) connecting the terminal and the brush arm (48), the conductor (47) comprising: a choke coil (63) extending in the direction of the rotation axis (O1) of the rotor; and a first plate member (62) that connects the brush arm (48) and the choke coil (63), wherein the choke coil (63) is disposed closer to the first plate member (62) than the brush (16) when the brush holder (15) is viewed from the direction of the rotation axis (O1) in a plan view.

Description

Brush motor

Technical Field

The invention relates to a brush motor.

Background

Conventionally, for example, a brush motor described in patent document 1 is known.

Documents of the prior art

Patent document 1: japanese patent laid-open publication No. 2017-70175

Problems to be solved by the invention

However, the conventional brush motor has room for improvement in downsizing.

Disclosure of Invention

The present invention has been made in view of the above circumstances, and an object thereof is to achieve downsizing of a brush motor.

Means for solving the problems

In order to solve the above problems, the present invention proposes the following means.

The brush motor according to the present invention includes: a rotor having a commutator; a brush holder holding a brush in contact with the commutator; and a terminal connected to a power supply and supplying power to the brush, the brush holder including: a fixed brush arm that applies a force to the brush toward the commutator; and a conductor connecting the terminal and the brush arm, the conductor including: a choke coil extending in a direction of a rotation axis of the rotor; and a first plate member connecting the brush arm and the choke coil, wherein the choke coil is disposed closer to the first plate member than the brush when viewed from a top view of the brush holder viewed from the direction of the rotation axis.

The choke extends in the direction of the rotation axis. Therefore, for example, the area exclusive for the choke coil in a plan view of the brush holder viewed from the direction of the rotation axis can be suppressed to be smaller than that in a case where the choke coil extends in the direction orthogonal to the rotation axis. Thus, the motor can be miniaturized.

The choke coil is disposed closer to the first plate member than the brush in the plan view. In other words, in the plan view, the shortest distance from the choke coil to the first plate member is shorter than the shortest distance from the choke coil to the brush. Therefore, the choke coil can be made less likely to interfere with the brush arm when the brush arm is deformed or displaced. As a result, the motor can be further miniaturized.

The choke coil extends in the direction of the rotation axis, and includes not only a case where the axis of the choke coil is parallel to the rotation axis but also a case where the axis is inclined by 30 degrees or less with respect to the rotation axis. The inclination angle of the axis line with respect to the rotation axis is preferably 15 degrees or less, more preferably 10 degrees or less, and further preferably 5 degrees or less.

In the above-described plan view, the brush arm may extend from near the first end portion of the first plate member in a direction intersecting the first plate member, at least a part of the choke coil may be disposed in a region formed between a virtual line connecting a tip end portion of the brush arm and the second end portion of the first plate member, the brush arm, and the first plate member.

At least a part of the choke coil is disposed in the region in the plan view. Therefore, the motor can be further downsized compared to the case where the choke coil is disposed outside the region as a whole.

The brush holder may include: a tubular member in which the brush, the brush arm, and the conductor are disposed; and a wall member that divides the inside of the tube member into a first space in which the brush is disposed and a second space in which the conductor is disposed.

The wall member divides the inside of the barrel member into a first space and a second space. Therefore, abrasion powder of the brush generated in the first space can be left in the first space. Thus, the abrasion powder can be made less likely to intrude into the second space. When the abrasion powder enters the second space, there is a fear that an unintended short circuit between the devices constituting the conductor occurs, but the short circuit between the devices can be suppressed by suppressing the entry thereof.

The conductor may include: a pair of second plate members; and a thermistor sandwiched by the pair of second plate members.

The thermistor is sandwiched between the pair of second plate members, and when the wear powder enters the second space, there is a possibility that the thermistor does not function because the pair of second plate members are short-circuited. However, such a fear can be suppressed by the wall member.

The choke coil may be disposed in the second space.

If the abrasion powder reaches the choke coil, there is a fear that the windings are short-circuited. However, by disposing the choke coil in the second space, the choke coil is disposed on the side opposite to the brush with the wall member interposed therebetween, and this can be suppressed.

Effects of the invention

According to the present invention, the brush motor can be miniaturized.

Drawings

Fig. 1 is a perspective view of a motor according to an embodiment of the present invention.

Fig. 2 is an exploded perspective view of a housing, a stator, and a rotor constituting the motor shown in fig. 1.

Fig. 3 is an exploded perspective view of a brush holder and a terminal block constituting the motor shown in fig. 1.

Fig. 4 is a perspective view of a brush holder constituting the motor shown in fig. 1.

Fig. 5 is an exploded perspective view of the brush holder shown in fig. 4.

Fig. 6 is a plan view of the brush holder shown in fig. 4.

Description of the reference numerals:

10. electric machine

11. Rotor

15. Brush holder

16. Electric brush

23. Commutator

45. Barrel component

46. Wall component

47. Conductor for electric device

48. Brush arm

48a tip end portion

50. The first space

51. Second space

62. First plate member

62a first end

62b second end

63. Choke coil

64. Second plate component

65. Thermal resistor

L virtual line

O1 rotating shaft

And an R region.

Detailed Description

Next, a brush motor according to an embodiment of the present invention will be described with reference to fig. 1 to 6.

As shown in fig. 1 to 3, a brush motor 10 (hereinafter, simply referred to as "motor 10") includes a rotor 11, a stator 12, a housing 13, a terminal block 14, and a brush holder 15. As shown in fig. 2, the motor 10 is of a so-called inner rotor type, and a rotor 11 is disposed in a cylindrical stator 12. The rotor 11 includes a rotating shaft 21 and rotates about a rotating shaft O1 which is a central axis of the rotating shaft 21. Hereinafter, a direction perpendicular to the rotation axis O1 is referred to as a radial direction, and a direction around the rotation axis O1 is referred to as a circumferential direction.

The rotor 11 includes a core 22 and a commutator 23 in addition to the rotating shaft 21. The core 22 and the commutator 23 are mounted to the rotary shaft 21. The core 22 and the commutator 23 are offset from each other in the direction of the rotation axis O1. Spacers 24 are attached to the shaft 21 from both sides in the direction of the rotation axis O1.

Hereinafter, the side of the commutator 23 along the direction of the rotation axis O1 where the core 22 is present is referred to as a first side D1. The side where the commutator 23 exists with respect to the core 22 along the direction of the rotation axis O1 is referred to as a second side D2.

The stator 12 includes a magnet 25 and a magnet pin 26. A plurality of magnets 25 (two magnets in the illustrated example) are provided at intervals in the circumferential direction. The magnet pins 26 are disposed between circumferentially adjacent magnets 25. The stator 12 is formed in a cylindrical shape by these magnets 25 and magnet pins 26.

The housing 13 (large housing) accommodates the rotor 11 and the stator 12. The housing 13 is formed in a top cylindrical shape. In other words, the housing 13 is formed in a cylindrical shape that closes the end of the first side D1. A through hole through which the rotating shaft 21 passes is formed in the top wall portion 30 of the housing 13 (a wall portion that closes the end portion of the first side D1 of the housing 13). An oilless bearing 31 (oilless metal) for the rotating shaft 21 is also disposed on the top wall portion 30. The stator 12 is fixed to an inner peripheral surface of the housing 13.

As shown in fig. 3, the terminal block 14 is disposed on the second side D2 with respect to the housing 13. The terminal block 14 includes a cylindrical portion 35, a terminal port 36, and a terminal 37.

The cylindrical portion 35 and the terminal port 36 are integrally formed. The cylindrical portion 35 is formed in a bottomed cylindrical shape. In other words, the cylindrical portion 35 is formed in a cylindrical shape that closes the end portion of the second side D2 of the cylindrical portion 35. A hole into which the rotating shaft 21 is fitted is formed in a bottom wall portion 38 of the cylindrical portion 35 (a wall portion that closes the end portion of the second side D2 of the cylindrical portion 35). In the illustrated example, a Printed Circuit Board (PCB) 39, a sensor magnet 40, and a mounting PTC41 are accommodated in the cylindrical portion 35.

The terminal port 36 is formed in a cylindrical shape extending from the cylindrical portion 35 to the second side D2. A power supply (a power supply external to the motor 10) is installed in the terminal port 36.

The terminal 37 is embedded in the cylindrical portion 35 and the terminal port 36. A part of the terminal 37 is exposed into the terminal port 36. When a power supply is attached to the terminal port 36, the terminal 37 is connected to the power supply. A pair of terminals 37 are provided. The terminal 37 supplies power to the brush 16.

The brush holder 15 is disposed between the housing 13 and the terminal block 14 along the direction of the rotation axis O1. The brush holder 15 is mounted to the housing 13 from the second side D2. The brush holder 15 is attached to the terminal block 14 from the first side D1. As shown in fig. 4 to 6, the brush holder 15 includes a cylindrical member 45, a wall member 46, a conductor 47, and a brush arm 48. The wall member 46, the conductor 47, and the brush arm 48 are provided in a pair, respectively.

As shown in fig. 3, the cylindrical member 45 is formed in a bottomed cylindrical shape. The cylindrical member 45 is fitted into the cylindrical portion 35 of the terminal block 14. Between the cylindrical member 45 and the cylindrical portion 35, the above-described mounting PCB39, sensor magnet 40, and mounting PTC41 are arranged. The mounting PCB39, the sensor magnet 40, and the mounting PTC41 are disposed on the second side D2 with respect to the bottom wall portion 49 of the tubular member 45. The wall member 46, the conductor 47, and the brush arm 48 are disposed on the first side D1 with respect to the bottom wall portion 49 of the tubular member 45. Further, an oilless bearing 57 (oilless metal) for the rotation shaft 21 is disposed on the bottom wall portion 49.

As shown in fig. 5, the wall member 46 divides the inside of the barrel member 45 into a first space 50 and a pair of second spaces 51. The brush 16, the shaft 21, the brush arm 48, and the oilless bearing 57 are disposed in the first space 50. The conductor 47 (including a choke coil 63 described later) and the ground terminal 59 are disposed in the second space 51.

The pair of wall members 46 are opposed to each other in the radial direction with the rotation shaft 21 interposed therebetween. The pair of wall members 46 extend from the bottom wall portion 49 of the cylindrical member 45 toward the first side D1. The end portions of the second sides D2 of the pair of wall members 46 are connected to the bottom wall portion 49.

The wall member 46 includes a first wall portion 52, a first bent portion 53, a second wall portion 54, a second bent portion 55, and a third wall portion 56. In the counterclockwise direction when the brush holder 15 is viewed from the first side D1, the first wall portion 52, the first curved portion 53, the second wall portion 54, the second curved portion 55, and the third wall portion 56 are arranged in this order. Hereinafter, the counterclockwise direction when viewing the brush holder 15 from the first side D1 will be simply referred to as the counterclockwise direction CCW, and the clockwise direction when viewing the brush holder 15 from the first side D1 will be simply referred to as the clockwise direction CW.

The first wall portion 52 extends from the inner peripheral surface of the tubular member 45 into the tubular member 45. The first wall portion 52 and the second wall portion 54 are connected via the first bent portion 53. In other words, the second wall portion 54 extends from the first wall portion 52 in a direction intersecting the first wall portion 52. The first curved portion 53 projects radially outward. The second wall portion 54 and the third wall portion 56 are connected via a second bent portion 55. In other words, the third wall portion 56 extends from the second wall portion 54 in a direction intersecting the second wall portion 54. The second curved portion 55 protrudes in the circumferential direction. The third wall portion 56 is parallel to the first wall portion 52. The third wall portion 56 forms a gap 58 with the inner peripheral surface of the cylindrical member 45. A part of the brush arm 48 (a fixing portion 70 described later) is disposed in the gap 58.

As shown in fig. 6, the pair of second spaces 51 is disposed on the outer peripheral portion of the space in the tubular member 45 when the brush holder 15 is viewed in a plan view from the direction of the rotation axis O1. The pair of second spaces 51 are provided at intervals in the circumferential direction. The pair of second spaces 51 has the same size in the plan view. A second space 51 is narrower than the first space 50. The pair of second spaces 51 are arranged substantially in point symmetry about the rotation shaft 21.

Conductors 47 connect the terminals 37 to the brush arms 48. The pair of conductors 47 are disposed in the second spaces 51, respectively. The pair of conductors 47 are opposed to each other across the rotating shaft 21 in the radial direction. The pair of conductors 47 are arranged substantially in point symmetry about the rotation shaft 21. The pair of conductors 47 includes a first conductor 60 and a second conductor 61. The first conductor 60 and the second conductor 61 are disposed in different second spaces 51, respectively.

As shown in fig. 4 to 6, the first conductor 60 includes a laminated body 66, a choke coil 63, and a first plate member 62. The laminated body 66, the choke coil 63, and the first plate member 62 are arranged in this order from the terminal 37 toward the brush arm 48.

The laminated body 66 includes the thermistor 65 and the pair of second plate members 64.

One of the pair of second plate members 64 (hereinafter, referred to as "terminal-side second plate member 64 a") is connected to the terminal 37, and the other second plate member 64 (hereinafter, referred to as "coil-side second plate member 64 b") is connected to the choke coil 63. The terminal-side second plate member 64a includes a bent portion protruding radially outward.

The thermistor 65 is formed of, for example, a metal foil of NiCu alloy. The thermistor 65 is sandwiched by the pair of second plate members 64. The thermistor 65 is sandwiched by the pair of second plate members 64 in the radial direction. At least a part of the thermistor 65 protrudes toward the first side D1 than the pair of second plate members 64. In the illustrated example, the pair of second plate members 64 and the thermistor 65 are arranged in the order of the terminal-side second plate member 64a, the thermistor 65, and the coil-side second plate member 64b from the radially outer side to the radially inner side.

As shown in fig. 5, the choke coil 63 includes a main body portion 67 and a pair of terminal portions 68. The body portion 67 has a spiral shape. The axis of the main body 67 is the axis O2 of the entire choke coil 63. A ferrite core 69 (core, magnetic core) is disposed in the main body portion 67. The pair of terminal portions 68 extend from the end portions of the main body portion 67, respectively. One of the pair of terminal portions 68 is fixed to the second plate member 64 (the second plate member 64b on the coil side), and the other is fixed to the first plate member 62. The pair of terminal portions 68 are fixed to the end portion of the first side D1 of the second plate member 64 and the end portion of the first side D1 of the first plate member 62, respectively.

The choke coil 63 extends in the direction of the rotation axis O1. In the illustrated example, the axis O2 of the choke coil 63 is parallel to the rotation axis O1. Here, the choke coil 63 extends in the direction of the rotation axis O1, and includes not only a case where the axis O2 of the choke coil 63 is parallel to the rotation axis O1 but also a case where the axis O2 is inclined by 30 degrees or less with respect to the rotation axis O1. The inclination angle of the axis O2 with respect to the rotation axis O1 is preferably 15 degrees or less, more preferably 10 degrees or less, and further preferably 5 degrees or less.

The first plate member 62 connects the choke coil 63 with the brush arm 48.

In the first conductor 60, the laminated body 66 and the first plate member 62 are arranged in this order in the counterclockwise direction CCW. The body portion 67 of the choke coil 63 is disposed radially inward of the first plate member 62.

The general structure of the second conductor 61 corresponds to the general structure of the first conductor 60. The second conductor 61 is different from the first conductor 60 in a point where one second plate member 64 is provided instead of the laminated body 66. In other words, the second conductor 61 does not include the thermistor 65, and includes only one second plate member 64. In the second conductor 61, the terminal 37 and the choke coil 63 are connected to one second plate member 64. The second plate member 64 of the second conductor 61 is provided with a bent portion in the same manner as the terminal-side second plate member 64a of the first conductor 60. In the second conductor 61, the second plate member 64 and the first plate member 62 are arranged in this order in the counterclockwise direction CCW.

As shown in fig. 6, the first conductor 60 and the second conductor 61 are arranged such that corresponding devices are opposed to each other in the radial direction with the rotation shaft 21 interposed therebetween. Specifically, the laminated body 66 in the first conductor 60 is opposed to the second plate member 64 in the second conductor 61. The choke coil 63 and the first plate member 62 in the first conductor 60 face the choke coil 63 and the first plate member 62 in the second conductor 61.

The brush arm 48 urges the brush 16 toward the commutator 23. The brush 16 is in contact with the commutator 23. The brushes 16 are provided in a pair with the rotating shaft 21 (commutator 23) interposed therebetween in the radial direction. The brush 16 is urged radially inward by an elastic force. The brush 16 is, for example, a carbon brush.

The pair of brush arms 48 radially sandwich the rotating shaft 21. When the brush holder 15 is viewed in plan from the direction of the rotation axis O1, the pair of brush arms 48 extend from the first end 62a of the first plate member 62 (from the vicinity of the first end 62 a) in a direction intersecting the first plate member 62. Each brush arm 48 is formed from 1 sheet of material. As shown in fig. 5 and 6, each brush arm 48 includes a fixing portion 70, a holding portion 71, and a deforming portion 72.

The fixing portion 70 is fixed to the first end portion 62a of the first plate member 62. A part of the fixing portion 70 protrudes in the circumferential direction from the first end portion 62a, and is disposed in the gap 58. The holding portion 71 holds the brush 16. An opening is formed in the holding portion 71, and the brush 16 is fitted in the opening. The deformation portion 72 connects the fixing portion 70 and the holding portion 71. The deforming portion 72 is more easily deformed than the holding portion 71. In the illustrated example, the rib 71a is formed in the holding portion 71, but the rib is not formed in the deforming portion 72, and therefore the deforming portion 72 is more easily deformed than the holding portion 71. The deformation portion 72 deforms, thereby deforming the entire brush arm 48.

In a state where the rotor 11 is attached to the brush holder 15, the brush 16 is pushed from the inside to the outside in the radial direction by the commutator 23, and the brush arm 48 is elastically deformed. At this time, the brush 16 is pressed toward the commutator 23 due to the elastic restoring force of the brush arm 48. When the rotor 11 is disengaged from the brush holder 15, the brush arm 48 is not pressed by the commutator 23, and the brush arm 48 is not elastically deformed.

Although the rotor 11 is not shown in fig. 6, the shape of the brush arm 48 shown in fig. 6 shows the shape when the rotor 11 is attached to the brush holder 15. In other words, the brush arm 48 shown in fig. 6 has a shape of the brush arm 48 that is elastically deformed outward in the radial direction by the commutator 23.

In the state where the rotor 11 is attached to the brush holder 15, the choke coil 63 (main body portion 67) is disposed closer to the first plate member 62 than the brush 16 is in the plan view. That is, in the plan view, the shortest distance from the choke coil 63 (the main body portion 67) to the first plate member 62 is shorter than the shortest distance from the choke coil 63 (the main body portion 67) to the brushes 16.

In the state where the rotor 11 is attached to the brush holder 15, the region R is formed between the virtual line L connecting the distal end portion 48a of the brush arm 48 and the second end portion 62b of the first plate member 62, the brush arm 48, and the first plate member 62 in the plan view. At least a part of the choke coil 63 (main body portion 67) is disposed in the region R. In the present embodiment, at least a part of the axis O2 of the choke coil 63 (in the illustrated example, the entire axis O2) is arranged in the region R. In the illustrated example, the axis O2 is located on the virtual line L.

In the present embodiment, the above positional relationship is also established in a state where the rotor 11 is detached from the brush holder 15. That is, even in a state not shown in the figure where the rotor 11 is separated from the brush holder 15, the choke coil 63 (the main body portion 67) is disposed closer to the first plate member 62 than the brush 16 is in the plan view. Even in this state, in the plan view, the region R between the virtual line L that connects the distal end portion 48a of the brush arm 48 and the second end portion 62b of the first plate member 62, the brush arm 48, and the first plate member 62 is formed, and at least a part of the choke coil 63 (main body portion 67) is disposed in the region R. However, the shapes of the virtual line L and the region R are different between the state where the rotor 11 is attached to the brush holder 15 and the state where it is not attached.

As described above, according to the motor 10 of the present embodiment, the choke coil 63 extends in the direction of the rotation axis O1. Therefore, for example, the area occupied by the choke coil 63 in the plan view can be reduced as compared with the case where the choke coil 63 extends in the direction orthogonal to the rotation axis O1. This can reduce the size of the motor 10.

The choke coil 63 is disposed closer to the first plate member 62 than the brush 16 is in the plan view. In other words, in the plan view, the shortest distance from the choke coil 63 to the first plate member 62 is shorter than the shortest distance from the choke coil 63 to the brush 16. Therefore, when the brush arm 48 is deformed or displaced, the choke coil 63 can be made less likely to interfere with the brush arm 48. As a result, the motor 10 can be further downsized.

At least a part of the choke coil 63 is disposed in the region R in the plan view. Therefore, the motor 10 can be further downsized as compared with the case where the entire choke coil 63 is disposed outside the region R.

The wall member 46 divides the inside of the barrel member 45 into a first space 50 and a second space 51. Therefore, abrasion powder of the brush 16 generated in the first space 50 can be left in the first space 50. This makes it possible to prevent the wear powder from entering the second space 51. In the case where abrasion powder intrudes into the second space 51, there is a fear that an unintended short circuit between the devices constituting the conductor 47 occurs, but by suppressing the intrusion thereof, the short circuit between the devices can be suppressed.

The thermistor 65 is sandwiched between the pair of second plate members 64, and when the wear debris intrudes into the second space 51, there is a possibility that the thermistor 65 does not function due to a short circuit of the pair of second plate members 64. Therefore, the wall member 46 can suppress such a fear.

If the abrasion powder reaches the choke coil 63, there is a fear that the windings are short-circuited. However, by disposing the choke coil 63 in the second space 51 and disposing the choke coil 63 on the side opposite to the brush 16 with the wall member 46 interposed therebetween, such a fear can be suppressed.

The technical scope of the present invention is not limited to the embodiments, and various changes can be made without departing from the scope of the present invention.

For example, the wall member 46 may be absent.

The choke coil 63 may be disposed entirely outside the region R.

The motor 10 may be an outer rotor instead of an inner rotor.

In addition, the components in the above embodiments may be replaced with known components as appropriate within a range not departing from the gist of the present invention, and the above modifications may be combined as appropriate.

Claims

1. A brush motor is provided with:

a rotor having a commutator;

a brush holder holding a brush in contact with the commutator; and

a terminal connected to a power source for supplying power to the brush,

the brush holder is provided with: a brush arm that applies a force to the brush toward the commutator; and a conductor connecting the terminal with the brush arm,

the conductor is provided with: a choke coil extending in a direction of a rotation axis of the rotor; and a first plate member connecting the brush arm with the choke coil,

the choke coil is disposed closer to the first plate member than the brush in a plan view of the brush holder as viewed from the direction of the rotation axis,

the brush arm extends from a first end of the first plate member in a direction intersecting the first plate member in the plan view, and at least a part of the choke coil is disposed in a region formed between a virtual line connecting another end of the brush arm different from the end connected to the conductor and a second end of the first plate member, the brush arm, and the first plate member.

2. The brushed electric motor of claim 1,

the brush holder is provided with: a tubular member in which the brush, the brush arm, and the conductor are disposed; and a wall member that divides the inside of the tube member into a first space in which the brush is disposed and a second space in which the conductor is disposed.

3. The brushed electric motor of claim 2,

the conductor is provided with: a pair of second plate members; and a thermistor sandwiched by the pair of second plate members.

4. The brushed electric motor of claim 2 or 3,

the choke coil is disposed in the second space.