JPH0621369U - Electric motor - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to provide an electric motor in which clogging between commutator pieces due to abrasion of a brush is eliminated to prevent rotation failure of the motor. . According to a first aspect of the invention, a plurality of commutator pieces 11 are provided.
In the electric motor in which the tips 27a and 27b of the brushes 27 slidably held in the brush holder 17 are brought into contact with the outer periphery of the drum type commutator 13 in which the The tip end side of the brush 27 is inclined in at least one direction of the central axis line direction of the commutator 13, and the invention of claim 2 is such that the tip end side of the brush 27 is branched in the central axis line direction of the commutator 13. It is formed into a Y shape.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to improvements in electric motors.

[0002]

[Prior art]

 2. Description of the Related Art Conventionally, an electric motor for driving a cooling fan for a vehicle radiator is a bearing made of sintered metal impregnated with oil at the upper and lower ends inside a casing 1, as shown in Japanese Utility Model Laid-Open No. 61-114968 or FIG. 3 is mounted, and the rotating shaft 5 is supported by the bearing 3. A magnet 9 is arranged on the inner peripheral surface of the casing 1 so as to face the rotor 7 attached to the rotary shaft 5.

A drum-type commutator 13 in which a plurality of commutator pieces 11 are arranged around the central axis L of the rotary shaft 5 is attached near the rotor 7, and the outer peripheral surface of the commutator 13 is attached. A pair of brushes 15 is in contact with the.

The brush 15 is slidably held in a brush holder 17 having a rectangular cross section fixed to the inner peripheral surface of the casing 1, and a spring 19 is provided in the brush holder 17. The tip end 15a of the brush 15 is brought into contact with the commutator 13 by the spring force of the spring 19 to supply power to the commutator 13.

In addition, in the figure, 21 is an oil-impregnated felt, 23 is a material for supporting the bearing 3, and 25 is a thrust washer.

[0006]

[Problems to be solved by the device]

 Thus, conventionally, the brush 15 mainly contains carbon or graphite, and the tip 15a of the brush 15 gradually wears as the commutator 13 rotates.

However, since the brush 15 is always in contact with the same portion of the outer periphery of the commutator 13, the abrasion powder of the brush 15 causes this contact surface, that is, the commutator piece 11 in the range indicated by the shaded portion A in the figure. There is a risk that clogging may occur and the motor may malfunction due to long-term use.

The present invention has been devised in view of the above circumstances, and an object thereof is to provide an electric motor in which clogging between commutator pieces due to abrasion of a brush is eliminated and rotation failure of the motor is prevented. To do.

[0009]

[Means for Solving the Problems]

 In order to achieve such an object, the invention according to claim 1 provides a tip of a brush slidably held in a brush holder on the outer periphery of a drum-type commutator in which a plurality of commutator pieces are arranged. In the abutting electric motor, the tip end side of the brush abutting the commutator is tilted in at least one direction of the central axis of the commutator.

According to a second aspect of the present invention, in the electric motor according to the first aspect, the brush is formed in a substantially Y-shaped cross section with its tip side branched in the direction of the central axis of the commutator. .

[0011]

[Action]

 According to the invention described in each claim, when the tip of the brush gradually wears as it is used, the brush is pushed out of the brush holder by the spring force of the spring. The contact surface of the brush tip with respect to the commutator will move in sequence as it is pushed out by force.

[0012]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same parts as those in the above-mentioned conventional example are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 1 is a sectional view of an essential part of an electric motor according to a first embodiment of the present invention, in which 27 is a brush slidably held in a brush holder 17, and the brush 27 is It is molded from the same material as the conventional brush 15.

Then, as shown in the figure, the brush 27 is formed in a substantially Y-shaped cross section, the tip end side of which is in contact with the commutator 13 and which is branched in the direction of the central axis L of the commutator 13 (rotating shaft 5). The tips 27a and 27b are in contact with both ends of the commutator 13 by the spring force of the springs 19 mounted in the brush holder 17, respectively.

Since this embodiment is constructed in this way, as shown in FIG. 2, the tips of the brushes 27 at the beginning of use are springs mounted in the brush holder 17, respectively. The spring force of 19 makes contact with the outer peripheries (hatched portions B and C in the drawing) of both ends of the commutator 13 to supply power to the commutator 13.

When the tips 27a and 27b of the brush 27 are gradually worn due to long-term use, the brush 27 is sequentially pushed out of the brush holder 17 by the spring force of the spring 19. As the brush 27 is sequentially pushed out by the spring force of the spring 19 due to the wear of the tip 19, the contact surfaces of the tips 27a and 27b with respect to the commutator 13 are, as shown in FIG. Further, the tip end 27b side is sequentially moved inward from the commutator 13 from the shaded portion C to the shaded portion E.

As described above, unlike the conventional example shown in FIG. 4, the electric motor according to the present embodiment does not have a structure in which the tips 27a and 27b of the brush 27 are always in contact with the same portion on the outer circumference of the commutator 13, Since the contact surface of the brush 27 with the commutator 13 changes as the tips 27a and 27b of the brush 27 wear, according to this embodiment, the combustor piece 11 of the commutator 13 is damaged by the abrasion powder of the brush 27. There is no partial clogging between them, and as a result, there is no longer a risk of the motor rotating poorly for long periods of use.

In the first embodiment described above, the brush 27 is formed into a substantially Y-shaped longitudinal section and the tips 27a and 27b thereof are branched. However, as in the second embodiment shown in FIG. The tip end side of the brush 29 that abuts against may be formed in a substantially V-shaped cross-section so as to be inclined in at least one direction of the central axis L direction of the commutator 13.

Therefore, according to this embodiment, at the beginning of use, the tip end 29a of the brush 29 comes into contact with the outer periphery of the commutator 13 on the one end side (hatched portion F in the figure), so that the commutator Power will be supplied to 13.

When the tip 29a of the brush 29 gradually wears with use, the brush 29 is similarly pushed out of the brush holder 17 by the spring force of the spring 19, but the brush 29 is worn by the abrasion of the tip 29a. When pushed out sequentially by the spring force of the spring 19, the contact surface of the tip end 29a with respect to the commutator 13 sequentially moves from the shaded portion F to the shaded portion G as shown in FIG.

Therefore, also in the present embodiment, as in the first embodiment, the abrasion powder of the brush 29 does not cause partial clogging between the commutator pieces 11 of the commutator 13. , The motor no longer has a risk of rotation failure after long-term use.

[0022]

[Effect of device]

 As described above, in the invention described in each claim, the contact surface of the brush with the commutator changes with the wear of the brush tip. The abrasion powder no longer partially clogs the commutator pieces of the commutator, and as a result, there is no risk that the motor will rotate improperly after long-term use.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of an essential part of an electric motor according to a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a main part of the electric motor shown in FIG. 1, showing a state in which wear of the brush has advanced.

FIG. 3 is an enlarged sectional view of an essential part of an electric motor according to a second embodiment of the present invention.

FIG. 4 is a sectional view of a main part of a conventional electric motor.

[Explanation of symbols]

 1 casing 3 bearing 5 rotating shaft 11 commutator piece 13 commutator 17 brush holder 19 spring 27, 29 brush

Claims (2)

[Scope of utility model registration request] 1. A brush (27) slidably held in a brush holder (17) on the outer periphery of a drum type commutator (13) having a plurality of commutator pieces (11) arranged therein.
In the electric motor having the tips (27a, 27b, 29a) of 29) abutting, the tip side of the brushes (27, 29) abutting the commutator (13) is moved in the central axis direction of the commutator (13). An electric motor characterized by being tilted in at least one direction. 2. The electric motor according to claim 1, wherein the brush (27) is formed so that its tip end side is branched in the direction of the central axis of the commutator (13) and has a substantially Y-shaped cross section.