JPH09322483A - Detector of wear limit of brush in dynamo-electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the forward movement of the brush of a dynamo-electric machine whose front end is brought into slide contact elastically with a slide contact part which is provided on a rotary shaft which is supported by a housing so as to rotate freely and which is supported by a fixed brush holder so as to be able to move in the radial direction of the rotary shaft even after the wear limit of the brush is detected and maintain the contact between the slide contact part and the brush securely. SOLUTION: The base end 21a of a spring member 21 which has a movable electrical contactor 22 which can be brought into/separated from contact with a fixed electrical contactor 19 on its tip part and has a position detection part 23 which can be brought into slide contact with one side surface 15b of a brush 15 at its middle part is fixed to a brush holder 14. The movable electrical contactor 22 is brough into contact with the fixed electrical contactor 19 while the position detection part 23 is brought into slide contact with the one side surface 15b but the movable electrical contactor 22 is separated from contact with the fixed electrical contactor 19 when the rear end surface 15c of the brush 15 passes the position detection part 23.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brush having a front end face elastically slidably contacting a sliding contact portion provided on a rotating shaft rotatably supported by a housing, along a radial direction of the rotating shaft. The present invention relates to a device for detecting a brush wear limit in a rotating electric machine that is movable and supported by a fixed brush holder.

[0002]

2. Description of the Related Art Conventionally, such a device is used, for example, as an actual flat plate
It is already known from Japanese Patent Publication No. 48363/1989.

[0003]

SUMMARY OF THE INVENTION In the above conventional one,
The movable electrical contact protruding in a pin shape from the side surface of the brush comes into contact with the fixed electrical contact from the rear side in response to the forward movement accompanying the wear of the brush, and thereby the wear limit of the brush is detected. However, since the forward movement of the brush is blocked by the contact of the movable electric contact with the fixed electric contact, if the brush is not replaced promptly when the wear limit of the brush is detected, the brush to the slip ring as the sliding contact part must be replaced. Sliding contact becomes impossible, the contact pressure of the brush to the slip ring drops, and the power supply to the rotary electric machine is cut off, or the power supply to the rotary electric machine becomes unstable. .

The present invention has been made in view of the above circumstances, and a brush in a rotary electric machine that is capable of advancing the brush even after detection of the wear limit and reliably maintaining the contact of the brush with the sliding contact portion. An object is to provide a wear limit detection device.

[0005]

In order to achieve the above-mentioned object, the invention according to claim 1 is such that the front end face is resiliently attached to a sliding contact portion provided on a rotary shaft rotatably supported by a housing. In a rotating electric machine in which a brush to be slidably contacted is supported by a fixed brush holder so as to be movable in the radial direction of the rotating shaft, a fixed electric contact is fixedly arranged at a position separated from one side surface of the brush, and the fixed electric contact is fixed. A spring member having a movable electric contact arranged at one end of the brush and capable of being brought into contact with and separated from the contact and arranged between the fixed electric contact at a tip portion thereof, and having a position detecting portion at an intermediate portion capable of sliding contact with the one side surface of the brush. A base end portion of the brush of the position detection portion is fixed to the brush holder by exerting a spring force in a direction that elastically slides the position detection portion onto one side surface of the brush, and the spring member is attached to the brush holder of the position detection portion. With sliding contact to the side While contacting the movable electrical contact to the fixed electrical contact, characterized in that the rear end surface of the brush is formed so allowed to separate the movable electrical contact from the stationary electrical contacts in response to passing through the position detection unit.

According to a second aspect of the present invention, in addition to the structure of the first aspect of the invention, the rear end surface of the brush is formed in an inclined surface which becomes a forward position as it separates from one side surface of the brush. It is characterized in that the position detecting portion of the member is formed in a shape capable of engaging with and abutting the rear end surface of the brush.

Further, in addition to the structure of the invention according to claim 1 or 2, the invention according to claim 3 is such that the base end portion of the spring member made of a conductive material is brought into contact with the rear end surface of the brush. The brush urging portion that exerts a spring force in the direction of slidingly contacting the front end face with the sliding contact portion is integrally connected, and a conducting wire for electricity is connected to the spring member.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below based on one embodiment of the present invention shown in the accompanying drawings.

1 to 4 show an embodiment of the present invention. FIG. 1 is a vertical sectional side view of a DC motor, FIG. 2 is an exploded perspective view showing a structure of a brush wear limit detecting device, and FIG. A vertical cross-sectional view of the main part before the brush reaches the wear limit,
FIG. 4 is a cross-sectional view corresponding to FIG. 3 when the brush reaches the wear limit.

Referring first to FIG. 1, a housing 5 of a DC motor as a rotary electric machine has a bottomed cylindrical housing main body 8 in which a front bracket 7 is provided at one end of a cylindrical portion 6, and a pump (not shown). The housing main body 8 and the rear bracket 9 coupled to the other end of the housing main body 8, and magnets 10 ... Are arranged at a plurality of positions on the inner surface side of the housing main body 8 at intervals in the circumferential direction.

A rotor 11 having a rotating shaft 12 concentric with the cylindrical portion 6 is arranged in the cylindrical portion 6 of the housing main body 8, and both ends of the rotating shaft 12 are rotated by a front bracket 7 and a rear bracket 9. Freely supported. Thus, the rotary shaft 12 is connected to the hydraulic pump in the rear bracket 9.

A commutator 13 as a sliding contact portion is provided on the rotor 11 on the rear bracket 9 side of the rotary shaft 12. Further, on the inner surface side of the rear bracket 9, a pair of brush holders 14, 1 is provided on the side of the commutator 13.
4 is fixedly arranged, and the brushes 15 and 15 held by both brush holders 14 and 14 are the commutator 1
Slidingly contacted to 3.

2 and 3, the brush holder 1
4 is a rectangular tube portion 14 having a quadrangular cross section made of a non-conductive material.
a and an end plate portion 14b coupled to the rear end (right end in FIG. 3) of the square tube portion 14a.
It is fixed to the rear bracket 9 with the axis of a along the radial direction of the commutator 13. The square tube portion 14a and the end plate portion 14b may be integrally formed, and the opening 16 is provided between the rear end of the square tube portion 14a and the end plate portion 14b.
Is formed. The brush 15 has a front end surface 15 a slidably contacting the commutator 13 and a brush holder 14
Of the brush 15 is slidably fitted to the square tube portion 14a, and the front end surface 15a of the brush 15 is formed in an arc shape corresponding to the outer peripheral surface of the commutator 13.

A support member 17 formed of a non-conductive material in a gate shape is fixed to the rear bracket 9 so as to straddle the brush holder 14 at a position near the commutator 13. On the other hand, a slit 18 having a front end open to the commutator 13 side and a rear end closed is formed on a side portion of the square tubular portion 14a of the brush holder 14 opposite to the rear bracket 9.
Is provided, and the brush 15 is inserted through the slit 18.
Fixed electric contact 19 so as to face one side surface 15b
Is fixed to the support member 17, and a conducting wire 20 for energization is connected to the fixed electric contact 19.

The position detecting section 2 having a movable electric contact 22 at its tip and capable of sliding contact with one side surface 15b of the brush 15.
The base end portion 21a of the spring member 21 having the intermediate portion 3 is fixed to the end plate portion 14b of the brush holder 14 by the rivet 24 or the like so that the movable electric contact 22 and the position detection portion 23 are arranged in the slit 18. , Movable electrical contact 22
Is arranged between the one side surface 15b of the brush 15 and the fixed electric contact 19 so as to be able to come into contact with and separate from the fixed electric contact 19 located at a position separated from the one side surface 15b of the brush 15. The spring member 21 is made of a conductive material, and is fixed to the brush holder 14 so that the movable electrical contact 2
It is formed so as to exert a spring force in a direction in which 2 is separated from the fixed electrical contact 19 and brought close to the brush 15, that is, in a direction in which the position detecting portion 23 elastically slidably contacts one side surface 15b of the brush 15.

The rear end surface 15c of the brush 15 is
5 is formed on the inclined surface which is located at the front position as it moves away from the one side surface 15 b of the spring member 21.
Reference numeral 3 is formed in a substantially V-shape so that the rear end surface 15c of the brush 15 can be engaged with and abut the rear end surface 15c when the rear end surface 15c passes through the position detecting portion 23 and advances.

A brush urging portion 25 is integrally connected to the base end portion 21a of the spring member 21. This brush energizing part 25
Is a substantially J-shape in a natural state where no external force is applied, but the brush 15 having the front end surface 15a in contact with the commutator 13 is fitted into the brush holder 14 so that Always in contact with the end face 15c,
A spring force is exerted that elastically urges the brush 15 in a direction in which the front end surface 15 a of the brush 15 is in sliding contact with the commutator 13.

A conductive wire 26 is connected to the base end portion 21a of the spring member 21 by soldering or the like, and the conductive wire 26 is drawn out of the brush holder 14 through the opening 16. Further, in the rectangular tube portion 14a of the brush holder 14,
A stopper 27 is integrally provided to abut on the portion of the spring member 21 near the base end portion 21a from the outside while the position detection portion 23 is in sliding contact with the one side surface 15b of the brush 15.

Next, the operation of this embodiment will be described. Until the brush 15 reaches the wear limit, the position detector 23 elastically comes into sliding contact with one side surface 15b of the brush 15 as shown in FIG. In this state, the movable electrical contact 22
Securely contacts the fixed electrical contact 19.

When the front end surface 15a of the brush 15 wears due to the elastic sliding contact with the commutator 13, the rear end surface 15c of the brush 15 advances according to the wear of the front end surface 15a, and the rear end surface 15c When passing through the position detecting portion 23, as shown in FIG. 4, the elastic force of the spring member 21 causes the position detecting portion 23 to move toward the rear end surface 15c of the brush 15,
Accordingly, the movable electric contact 22 is separated from the fixed electric contact 19. By separating the movable electric contact 22 from the fixed electric contact 19, it is possible to detect that the wear amount of the brush 15 has reached the limit.

Moreover, when the rear end surface 15c of the brush 15 passes through the position detecting portion 23, the position detecting portion 23 abuts and engages with the rear end surface 15c of the brush 15. In this state, the rotary shaft of the commutator 13 is rotated. Even if the brush 15 slightly vibrates back and forth due to eccentricity with respect to 12, the movable electric contact 22 does not come into contact with the fixed electric contact 19.
That is, the rear end surface 15c of the brush 15 is formed as an inclined surface which is located at the front position as it moves away from the one side surface 15b of the brush 15, and the brush 15 has an arrow 2
When a rearward force as shown by 8 is applied, the position detector 23 causes the arrow 29 from the rear end surface 15c of the brush 15 to move.
As indicated by, a force acts in a direction to move the movable electrical contact 22 away from the fixed electrical contact 19, and the force is upward between the contact portion of the spring member 21 with the stopper 27 and the position detection portion 23. It is absorbed by bending.

The spring force for urging the brush 15 toward the commutator 13 is obtained by the brush urging portion 25 integrated with the spring member 21, and a spring dedicated to the elastic urging of the brush 15 is unnecessary. Therefore, the number of parts can be reduced, and the brush holder 14 can be easily assembled.
Further, since the brush energizing portion 25 is connected to the conducting wire 26 for energization and also fulfills the energizing function to the brush 15, it is not necessary to connect a dedicated part such as a pigtail for energizing to the brush 15. This also makes it possible to reduce the number of parts.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various design changes can be made without departing from the present invention described in the claims. It is possible to do.

For example, the present invention can be applied not only to a DC motor but also to a DC generator, and also to a rotary electric machine using a slip ring as a sliding contact portion.

[0025]

As described above, according to the first aspect of the invention, the fixed electric contact is fixedly arranged at a position separated from one side surface of the brush, and the fixed electric contact can be brought into contact with and separated from the fixed electric contact. A base end portion of a spring member having a movable electric contact disposed between a side surface and the fixed electric contact at a tip portion and having a position detection portion capable of sliding contact with one side surface of the brush at an intermediate portion is a position detection portion. The spring member is fixed to the brush holder by exerting a spring force in a direction of elastically sliding contact with one side surface of the brush, and when the spring member is in sliding contact with the one side surface of the brush, the movable electric contact is The movable electrical contact is formed so as to be separated from the fixed electrical contact in response to the rear end surface of the brush passing through the position sensing portion, so that the rear end of the brush passes through the position sensing portion. Movable electrical contacts according to Be detected apart from the wear limit from the fixed electrical contacts, not the movement of the brush is inhibited, it is possible to maintain secure contact to sliding contact of the brush.

According to the second aspect of the present invention, the rear end surface of the brush is formed as an inclined surface that is located at the front position as it moves away from one side surface of the brush, and the position detecting portion of the spring member is the rear end surface of the brush. Since it is formed in a shape that can be engaged with and abutted against, the movable electric contact can be reliably separated from the fixed electric contact even if the brush vibrates back and forth, and both contacts are frequently repeatedly separated and contacted. It is possible to improve the detection accuracy of the wear limit by preventing the above.

Further, according to the third aspect of the present invention, the spring member made of a conductive material has a base end portion which is in contact with the rear end surface of the brush so that the front end surface of the brush is slidably contacted with the sliding contact portion. Since the brush energizing portion that exerts spring force is integrally connected and the conducting wire is connected to the spring member, it is possible to reduce the number of parts and simplify the electric wiring structure to the brush. can do.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view of a DC motor.

FIG. 2 is an exploded perspective view showing a configuration of a brush wear limit detection device.

FIG. 3 is a longitudinal cross-sectional view of a main part in a state before the brush reaches the wear limit.

FIG. 4 is a sectional view corresponding to FIG. 3 in a state where the brush has reached the wear limit.

[Explanation of symbols]

 5 ... Housing 12 ... Rotating shaft 13 ... Commutator as sliding contact portion 14 ... Brush holder 15 ... Brush 15a ... Brush front end surface 15b ... Brush one side surface 15c. ..Brush rear end surface 19 ... Fixed electric contact 21 ... Spring member 21a ... Spring member base end 22 ... Movable electric contact 23 ... Position detection unit 25 ... Brush energizing Part 26 ... Conductor

Claims (3)

[Claims] 1. A brush (15) for elastically slidingly contacting a front end face (15a) with a sliding contact portion (13) provided on a rotating shaft (12) rotatably supported by a housing (5). , A rotary electric machine supported by a fixed brush holder (14) capable of moving in a radial direction of the rotary shaft (12), a fixed electric contact (a position) separated from one side surface (15b) of the brush (15). 19) is fixedly arranged and is movable between the fixed electric contact (19) and the movable electric contact (22) arranged between the fixed electric contact (19) and one side surface (15b) of the brush (15). The base end portion (21a) of the spring member (21) having the position detection portion (23) at the tip portion and having the position detection portion (23) capable of sliding contact with one side surface (15b) of the brush (15) is the position detection portion. (23) to one side (1 5b) is fixed to the brush holder (14) by exerting a spring force in the direction of elastically sliding contact with 5b),
When the spring member (21) is in sliding contact with the one side surface (15b) of the brush (15) of the position detection part (23), the movable electric contact (22) is brought into contact with the fixed electric contact (19). The rear end surface (15c) of the (15) is the position detecting section (2
3) A brush wear limit detecting device for a rotating electric machine, which is formed so as to separate the movable electric contact (22) from the fixed electric contact (19) as it passes through 3). 2. The rear end surface (15c) of the brush (15) is
The spring member (2) is formed on an inclined surface that is located at the front position as it separates from one side surface (15b) of the brush (15).
The brush wear limit detecting device for a rotating electric machine according to claim 1, wherein the position detecting portion (23) of (1) is formed in a shape capable of engaging with and abutting the rear end surface (15c) of the brush (15). . 3. A spring member (21) made of a conductive material is brought into contact with a rear end surface (15c) of a brush (15) and a front end surface (15a) of the brush (15) is slidably contacted with a rear end surface (15c) of the brush (15). (1
The brush urging portion (25) that exerts a spring force in a direction of sliding contact with the spring member (3) is integrally connected to the spring member (2).
The brush wear limit detecting device for a rotating electric machine according to claim 1 or 2, wherein a conducting wire (26) for energization is connected to 1).