WO2019065237A1

WO2019065237A1 - Motor

Info

Publication number: WO2019065237A1
Application number: PCT/JP2018/033787
Authority: WO
Inventors: 隆宏檜皮
Original assignee: 日本電産株式会社
Priority date: 2017-09-29
Filing date: 2018-09-12
Publication date: 2019-04-04
Also published as: CN111066229A

Abstract

A brushed motor has: a rotor comprising a commutator, the rotor being supported so as to be capable of rotating about a center axis that extends horizontally in a forward/rearward direction; a casing that accommodates at least a portion of the rotor; a brush card disposed inside the casing, the brush card having a discoid portion having a discoid shape that expands in a direction orthogonal to the center axis; and a brush positioned forward of the brush card, the brush being supported by the brush card and being in contact with the commutator. The casing comprises: a cup-shaped housing having a cylindrical portion; and a cup-shaped back cover disposed rearward of the housing, the back cover constituting the casing together with the housing. The housing and/or the back cover has a flange part that expands radially outward from an opening. The axial-direction position of the outer peripheral surface of the brush card overlaps the flange part. The outer peripheral surface of the brush card and the housing and back cover face each other with a gap interposed therebetween.

Description

motor

The present invention relates to a motor.

Conventionally, a motor having a brush is known. The structure of a motor having a brush is described, for example, in Japanese Patent Publication No. 3971349. The motor of the publication has a rotatable armature and a brush in sliding contact with the armature's commutator (paragraphs 0018 to 0019). In addition, the brush of the publication is connected to an external power supply, and supplies power to the armature through the commutator (paragraph 0019).
Japanese Patent Publication: Japanese Patent No. 3971349

A motor having a brush may be used in an environment susceptible to droplets, such as, for example, the interior of a car. In that case, it is preferable to suppress at least the adhesion of droplets to the conductive brush. For this reason, it is required that the droplet which has invaded the inside of the motor does not reach the brush.

An object of the present invention is to provide a structure capable of suppressing the adhesion of droplets to a brush without increasing the number of parts in a motor having the brush.

According to an exemplary first aspect of the present invention, there is provided a rotating unit having a commutator, supported rotatably around a central axis extending horizontally in the back and forth direction, a housing accommodating at least a part of the rotating unit, and A brush card having a disc-like disc portion disposed inside and extending in a direction orthogonal to the central axis, and a brush located on the front side of the brush card, held by the brush card, and contacting the commutator And the housing includes a cup-shaped housing having a cylindrical portion, and a cup-shaped back cover disposed on the rear side of the housing and forming a housing together with the housing, the housing And at least one of the back cover has a flange portion extending radially outward from the opening, and an outer peripheral surface of the brush card is in axial direction with the flange portion. It is a motor with a brush which a position overlaps and the outer peripheral surface of the said brush card | curd, and the said housing and the said back cover oppose through the clearance gap.

According to the first exemplary invention of the present application, a droplet which has invaded the inside of the housing is held in the gap. Therefore, the adhesion of droplets to the brush can be suppressed without increasing the number of parts.

FIG. 1 is a longitudinal sectional view of a motor according to a first embodiment. FIG. 2 is a front view of the back cover, the brush card, and the connector member according to the first embodiment. FIG. 3 is an enlarged view of an essential part of a longitudinal sectional view of the motor according to the first embodiment.

Hereinafter, exemplary embodiments of the present invention will be described. In the present application, a direction parallel to the central axis of the motor is "axial direction", a direction perpendicular to the central axis of the motor is "radial direction", and a direction along an arc centered on the central axis of the motor is "circumferential direction" , Respectively. Further, in the present application, the shape and the positional relationship of each part will be described with the axial direction as the front-rear direction and the housing side front to the back cover. Further, in the present application, the “parallel direction” also includes a substantially parallel direction. Further, in the present application, the “orthogonal direction” also includes a substantially orthogonal direction.

<1. Overall configuration of motor>
A first embodiment of the present invention will be described. FIG. 1 is a longitudinal sectional view of a motor 1 according to the first embodiment. The motor of the present embodiment is mounted, for example, on a car and used as a drive source of an engine cooling fan. As shown in FIG. 1, the motor 1 has a stationary unit 2 and a rotating unit 3. The stationary unit 2 is fixed to a frame of a device to be driven. The rotating unit 3 is rotatably supported with respect to the stationary unit 2.

The stationary unit 2 of the present embodiment includes a housing 21, a plurality of magnets 22, a back cover 23, a brush card 24, a plurality of brushes 25, a connector member 26, a front bearing 27, and a rear bearing 28. FIG. 2 is a front view of the back cover 23, the brush card 24, and the connector member 26. As shown in FIG.

The housing 21 is a substantially cup-shaped member opened rearward. At least a portion of the rotating portion 3 is accommodated inside the housing 21. The housing 21 is formed of, for example, a metal such as a galvanized steel sheet. However, other materials such as resin may be used as the material of the housing 21.

As shown in FIG. 1, the housing 21 has a front wall portion 211, a front peripheral wall portion 212 and a housing flange portion 214. The front wall portion 211 extends in a substantially disc shape in the direction orthogonal to the central axis 9 in front of an armature 32 described later. The front wall portion 211 is a bottom portion. At the center of the front wall portion 211, a front bearing holding portion 213 for holding the front bearing portion 27 is provided. The front wall portion 211 is provided with a plurality of vent holes 215 which are holes penetrating in the axial direction. The front peripheral wall portion 212 extends in a substantially cylindrical shape from the outer peripheral portion of the front wall portion 211 toward the rear side. The front peripheral wall portion 212 is a cylindrical portion.

The housing flange portion 214 is an annular portion extending radially outward from the rear end portion of the front peripheral wall portion 212. The rear end portion of the front peripheral wall portion 212 is an opening. The housing flange portion 214 is provided over the entire circumference. The housing flange portion 214 is a flange portion.

The radially inner surface connecting the front peripheral wall portion 212 and the housing flange portion 214 is a curved surface 2121. In other words, the housing 21 has a curved surface 2121 at the base of the flange portion.

The plurality of magnets 22 are fixed to the inner peripheral surface of the front peripheral wall portion 212. The radially inner surface of the plurality of magnets 22 is a magnetic pole surface radially opposed to an armature 32 described later. The plurality of magnets 22 are arranged at substantially equal intervals in the circumferential direction so that the magnetic pole surfaces of the N pole and the magnetic pole surfaces of the S pole are alternately arranged. In place of the plurality of magnets 22, one annular magnet may be used in which the N pole and the S pole are alternately magnetized in the circumferential direction.

The back cover 23 is a substantially cup-shaped member opened toward the front side. The back cover 23 is disposed on the rear side of the housing 21. The back cover 23 is formed of, for example, a metal such as a galvanized steel sheet. However, other materials such as resin may be used as the material of the back cover 23. The plurality of magnets 22, the brush card 24, the plurality of brushes 25, an armature 32 to be described later, and a commutator 33 to be described later are accommodated in a housing formed of a housing 21 and a back cover 23.

The back cover 23 has a first rear wall portion 231, a first peripheral wall portion 232, and a back cover flange portion 237. The first rear wall portion 231 extends in a substantially disc shape in the direction orthogonal to the central axis 9 on the rear side of the brush card 24. The first back wall portion 231 is a bottom portion. At the center of the first rear wall portion 231, a rear bearing holding portion 233 for holding the rear bearing portion 28 is provided. The first rear wall portion 231 is provided with a plurality of vents 239 which are holes penetrating in the axial direction. The first peripheral wall portion 232 extends in a substantially cylindrical shape from the outer peripheral portion of the first rear wall portion 231 toward the front side. The inner circumferential surface of the first circumferential wall portion 232 and the inner circumferential surface of the front circumferential wall portion 212 have different inner diameters. In the present embodiment, the inner diameter of the first peripheral wall portion 232 is larger than the inner diameter of the front peripheral wall portion 212.

The first peripheral wall portion 232 has a through hole 234 and a notch 235. As shown in FIG. 2, the through hole 234 vertically penetrates the first peripheral wall portion 232 in the vicinity of the lower end portion of the first peripheral wall portion 232. The through hole 234 is a drainage port located on the lower side in the direction of gravity. Further, as shown in FIG. 2, the notch 235 penetrates the first peripheral wall portion 232 in the radial direction on the upper side of the through hole 234. In the present embodiment, the notch 235 is disposed at a height position substantially equal to the central axis 9, that is, a position approximately 90 ° away from the through hole 234 with respect to the central axis 9.

The back cover flange portion 237 is an annular portion extending radially outward from the front end portion of the first peripheral wall portion 232. The back cover flange portion 237 is provided over the entire circumference. The back cover flange portion 237 is a flange portion.

The radially inner surface connecting the first peripheral wall portion 232 and the back cover flange portion 237 is a curved surface 2321. In other words, the back cover 23 has a curved surface 2321 at the base of the flange portion.

The housing flange portion 214 and the back cover flange portion 237 face each other in the axial direction. Either one of the housing flange portion 214 and the back cover flange portion 237 is provided with a crimped portion projecting in the axial direction toward the other side. In the present embodiment, the caulking portion is a caulking portion 238 provided on the back cover 23. When the caulking portion 238 is caulked and contacts the housing flange portion 214 (not shown), the housing 21 and the back cover 23 are fixed to form a housing.

The brush card 24 is disposed on the front side of the first rear wall portion 231 and radially inward of the first peripheral wall portion 232. For the material of the brush card 24, for example, a resin which is an insulator is used. As shown in FIGS. 1 and 2, the brush card 24 has a second back wall portion 241 and a second peripheral wall portion 242. The second rear wall portion 241 extends in a substantially disc shape in the direction orthogonal to the central axis 9 on the front side of the first rear wall portion 231. The second back wall portion 241 is a disc portion. In the center of the second rear wall portion 241, a circular hole 243 for disposing the rear bearing holding portion 233 or the commutator 33 described later is provided. The second peripheral wall portion 242 extends in a substantially cylindrical shape from the outer peripheral portion of the second rear wall portion 241 toward the front side. The outer peripheral surface of the second rear wall portion 241 and the outer peripheral surface of the second peripheral wall portion 242 are outer peripheral surfaces of the brush card 24. The outer peripheral surface of the brush card 24, the inner peripheral surface of the housing 21, and the inner peripheral surface of the back cover 23 face each other via a gap 29. Further, the axial position of the outer peripheral surface of the brush card 24 and the axial position of the housing flange portion 214 overlap. The axial position of the outer peripheral surface of the brush card 24 and the axial position of the back cover flange portion 237 overlap. That is, the outer peripheral surface of the brush card 24 overlaps with the position in the axial direction with the flange portion. In the present embodiment, the brush card 24 faces the flange portion via the gap 29 at the second peripheral wall portion 242.

The plurality of brushes 25 are held by the brush card 24. Each brush 25 is a conductor in contact with a commutator 33 described later. As shown in FIG. 1, in the present embodiment, the plurality of brushes 25 are disposed on the front side of the second rear wall portion 241 and radially inward of the second peripheral wall portion 242. Thereby, the adhesion of the droplets to the brush 25 is suppressed. Each brush 25 has a contact surface 251 that contacts the segment 331 of the commutator 33. Each brush 25 is urged radially inward by a spring 252 interposed between the brush 25 and the second peripheral wall portion 242. The contact surface 251 is thereby pressed against the segment 331. As a result, the brush 25 and the segment 331 are electrically conducted.

The connector member 26 is a member for supporting a lead connecting the brush 25 and an external power supply. As a material of the connector member 26, for example, a resin which is an insulator is used. The connector member 26 is disposed radially outward of the brush card 24. Further, the connector member 26 is fixed to the back cover 23 in a state of being fitted in the notch 235 of the back cover 23.

Also, the connector member 26 has one or more communication holes 261. The communication hole 261 penetrates the connector member 26 in the radial direction. The lead wire extending from the external power supply is connected to the brush 25 through the communication hole 261 of the connector member 26 and the unshown bus bar.

The bus bar is fixed to the brush card 24. Also, there are bus bars for grounding as well as those interposed between lead wires and brushes. The ground bus bar protrudes radially outward from the brush card 24, and its tip end is located between the housing flange portion 214 and the back cover flange portion 237. When the caulking portion 238 is caulked and the housing 21 and the back cover 23 are fixed, the ground bus bar is also fixed. In addition, the brush card 24 is supported by the housing by fixing the ground bus bar to the housing.

The front bearing portion 27 and the rear bearing portion 28 are mechanisms for rotatably supporting the shaft 31 on the rotating portion 3 side. For the front bearing portion 27 and the rear bearing portion 28 of the present embodiment, for example, a ball bearing that relatively rotates an outer ring and an inner ring via a ball is used. The outer ring of the front bearing portion 27 is fixed to the front bearing holding portion 213 of the housing 21. The outer ring of the rear bearing portion 28 is fixed to the rear bearing holding portion 233 of the back cover 23. Further, inner rings of the front bearing portion 27 and the rear bearing portion 28 are fixed to the shaft 31. However, instead of the ball bearings, other types of bearings such as slide bearings and fluid bearings may be used.

The rotary unit 3 of the present embodiment has a shaft 31, an armature 32 and a commutator 33.

The shaft 31 is disposed along a central axis 9 extending substantially horizontally forward and backward. The shaft 31 is supported by the front bearing portion 27 and the rear bearing portion 28 and rotates about the central axis 9. In addition, the shaft 31 has a head portion 311 projecting forward from the front wall portion 211 of the housing 21. The head 311 is attached with a component to be driven, for example, an impeller.

The armature 32 is disposed radially inward of the plurality of magnets 22. The armature 32 has an armature core 41 and a coil 42. The armature core 41 is formed of, for example, a laminated steel plate. The armature core 41 has an annular core back 411 and a plurality of teeth 412 protruding radially outward from the core back 411. The shaft 31 is press-fit into the core back 411 in the radial direction. The plurality of teeth 412 are arranged at equal intervals in the circumferential direction. The coil 42 is constituted by a conductive wire wound around the teeth 412.

The commutator 33 is fixed to the shaft 31 on the rear side of the armature 32. A plurality of conductive segments 331 are provided on the outer peripheral surface of the commutator 33 at equal intervals in the circumferential direction. Moreover, the lead wire drawn from the coil 42 is electrically connected to each segment 331.

The drive current supplied from the external power supply flows to the coil 42 through the lead wire, the brush 25 and the segment 331. When a drive current is supplied to the coil 42, a magnetic flux is generated in the teeth 412. Then, a torque in the circumferential direction is generated by the magnetic attraction or repulsion between the teeth 412 and the magnet 22. As a result, the rotating unit 3 rotates around the central axis 9 with respect to the stationary unit 2. In addition, when the commutator 33 rotates, the contact surface 251 of each brush 25 sequentially contacts the plurality of segments 331. Thereby, the drive current is supplied to the plurality of coils 42 sequentially. As a result, the rotating unit 3 rotates continuously.

<2. About drainage structure>
Subsequently, the drainage structure of the motor 1 according to the present embodiment will be described.

FIG. 3 is an enlarged view of an essential part of a longitudinal sectional view of the motor according to the present embodiment. With reference to FIGS. 1 and 3, in the present embodiment, the outer peripheral surface of the second circumferential wall 242 and the front circumferential wall 212 and the first circumferential wall 232 face each other with a gap 29 interposed therebetween. That is, the outer peripheral surface of the brush card and the flange portion face each other via the gap 29. In the gap 29, the droplet 291 which has invaded into the housing can be held by surface tension. Specifically, the width w of the narrowest portion of the gap 29 is between 0.1 mm and 0.7 mm. With this width, when a droplet infiltrates the gap 29, surface tension is caused by surface tension. The droplet 291 is held. If the width w of the narrowest portion of the gap 29 is larger than 0.7 mm, the droplet passes through the gap. In addition, if the width w of the narrowest portion of the gap 29 is smaller than 0.1 mm, the air that has entered the casing from the vent becomes difficult to flow. Therefore, the width w of the narrowest portion of the gap 29 is preferably 0.1 mm to 0.7 mm.

The gap 29 is formed on the entire circumference radially inward of the flange portion. Thereby, the droplet 291 can be held in the gap 29. The droplets 291 held in the gap 29 move downward by gravity. When the droplets accumulate on the lower side of the gap 29, a part thereof is discharged from the gap 29 through the through hole 234 to the outside of the housing. Here, the diameter of the first circumferential wall portion 232 is larger than that of the front circumferential wall portion 212. That is, on the lower side in the gravity direction, the first peripheral wall portion 232 is positioned lower than the front peripheral wall portion 212 in the gravity direction. Since the through holes 234 are provided in the first peripheral wall portion 232, droplets accumulated in the gap 29 are easily moved to the through holes 234.

Further, a radially inner surface connecting the front peripheral wall portion 212 and the housing flange portion 214 is a curved surface 2121, and a radial inner surface connecting the first peripheral wall portion 232 and the back cover flange portion 237 is a curved surface 2321. When these curved surfaces and the outer peripheral surface of the brush card 24 face each other, a so-called tapered surface which is inclined in the axial direction is formed. This makes it easier to hold the droplets 291 in the gap 29. Furthermore, when the curved surface 2121 of the housing 21 and the curved surface 2321 of the back cover 23 axially face each other, a tapered surface is formed outward in the radial direction. Thereby, the droplet 291 can be more easily held in the gap 29.

As a path through which droplets are transmitted to the brush 25, it is conceivable that a droplet infiltrates from a vent or the like and adheres to the inner circumferential surface of the housing and passes from the inner circumferential surface of the housing 21 to the brush 25 through the brush card 24. . However, according to the configuration of the present embodiment, the droplets transmitted from the inner circumferential surface of the housing 21 move to the gap 29 by surface tension and are held in the gap 29, and move downward in the direction of gravity in the gap 29. And is discharged from the through hole 234. Therefore, it is possible to suppress the adhesion of droplets to the brush 25 along the brush card 24 from the inner peripheral surface of the housing 21.

<3. Modified example>
Although the exemplary embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments.

The motor of the present invention may be a motor for rotating an on-vehicle fan, or may be a motor used for another application. For example, the motor of the present invention may be used as a driving source of power steering of a car. Further, the motor of the present invention may be mounted on a home appliance, an OA device, a medical device or the like to generate various driving forces.

However, the present invention is particularly useful for motors used in an environment susceptible to droplets. Therefore, the present invention is particularly useful for a motor mounted on transportation equipment such as a car, and a fan motor for cooling a server installed outdoors, a router, a communication base, a switch device and the like.

The number of through holes provided in the back cover may be one as in the above embodiment, or may be two or more. Also, the position of the connector member may not necessarily be about 90 ° away from the through hole with respect to the central axis 9. Further, the shape of the detail of each member may be different from the shape shown in each drawing of the present application. In addition, the drainage structure of the present invention and a seal member such as an O-ring or a gasket may be used in combination.

Although both the housing and the back cover had a curved surface at the base of the flange portion, they may have a curved surface at the base of the flange portion of only the housing or the back cover alone.

In addition, each element appearing in the above-described embodiment and modification may be combined appropriately as long as no contradiction occurs.

The present invention is applicable to motors.

Reference Signs List 1 motor, 2 stationary portion, 3 rotating portion, 9 central shaft, 21 housing, 22 magnet, 23 back cover, 24 brush card, 25 brush, 26 connector member, 27 front bearing portion, 28 rear bearing portion, 29 gap, 31 Shaft, 32 armature, 33 commutator, 41 armature core, 42 coil, 211 front wall, 212 front peripheral wall, 214 housing flange, 231 first rear wall, 232 first peripheral wall, 234 through hole, 235 notch , 237 back cover flange portion, 241 second rear wall portion, 242 second peripheral wall portion, 2121, 2321 curved surface

Claims

A rotary unit rotatably supported about a central axis extending horizontally in the longitudinal direction and having a commutator;
A housing that accommodates at least a portion of the rotating portion;
A brush card disposed inside the housing and having a disc-like disc portion extending in a direction orthogonal to the central axis;
A brush located on the front side of the brush card, held by the brush card, and in contact with the commutator;
Have
The housing is
A cup-shaped housing having a cylindrical portion;
A cup-shaped back cover disposed on the rear side of the housing and forming a housing together with the housing;
At least one of the housing and the back cover has a flange portion extending radially outward from the opening,
The outer peripheral surface of the brush card has an axial position overlapping the flange portion,
The motor with a brush which the outer peripheral surface of the said brush card, the said housing, and the said back cover oppose via the clearance gap.
The brushed motor according to claim 1, wherein the gap is capable of holding a droplet that has entered the housing by surface tension.
A brushed motor according to claim 1 or 2, wherein the width of the narrowest part of the gap is between 0.1 mm and 0.7 mm.
The housing and the back cover are formed of metal,
The brushed motor according to claim 3, wherein a material of the brush card is a resin.
The brushed motor according to claim 4, wherein the housing and the back cover are formed of galvanized steel sheets.
The brushed motor according to any one of claims 1 to 5, wherein both the housing and the back cover have a flange portion.
The brushed motor according to any one of claims 1 to 6, wherein at least one of the housing and the back cover has a curved surface at a base of a flange portion.
The brushed motor according to any one of claims 1 to 7, wherein both the housing and the back cover have curved surfaces at the base of a flange portion.
The brushed motor according to any one of claims 1 to 8, wherein the inner circumferential surface of the housing and the inner circumferential surface of the back cover have different inner diameters.
The brushed motor according to any one of claims 1 to 9, wherein at least one of the housing and the back cover has a vent that is an axially open hole at the bottom.
The brush card has a second peripheral wall extending forward from the disc portion,
The brushed motor according to any one of claims 1 to 10, wherein the second peripheral wall portion faces the flange portion with a gap.
The brushed motor according to any one of claims 1 to 11, wherein the housing has a drainage port on the lower side in the direction of gravity.