JPH0145247Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a noise prevention structure for a motor with a commutator such as an electric motor.

For automobile wiper drive motors, etc.
A structure in which a plurality of speed switching brushes are provided for speed switching is common. Therefore, in order to prevent spark noise between the brush and the commutator on the armature side from going outside, noise countermeasures are required for each brush.

FIG. 1 shows a conventional noise prevention structure of a motor with a commutator. In this figure, a motor 1 with a commutator has brushes 2A, 2B, 2 that contact the commutator on the armature side.
C, and the brush 2A is attached to the motor frame 3.
It is also connected to the negative electrode of the DC power supply 4. The brushes 2B and 2C are for speed switching, and are connected to the positive electrode of a DC power source 4 via a speed changeover switch 5. Here, in order to prevent noise, independent choke coils L1 and L2 are inserted into the connection lines between the brushes 2B and 2C and the DC power source 4, respectively, and capacitors C1 and C2 are connected between each of the brushes 2B and 2C and the motor frame 3. established in

By the way, in the above configuration, it is necessary to provide independent chain coils L1 and L2 corresponding to the speed switching brushes 2B and 2C, and these need to be placed inside the motor frame 3, which makes it difficult to downsize. This is a hindrance and is disadvantageous in terms of cost.

The present invention focuses on the fact that only one brush for speed switching is always selected and multiple brushes are not energized at the same time, and a single magnetic core has multiple windings corresponding to the number of brushes for speed switching. By inserting each winding between those brushes and the power supply,
The present invention aims to provide a noise prevention structure for a commutator-equipped motor that is compact and cost-reduced.

Embodiments of the noise prevention structure for a motor with a commutator according to the present invention will be described below with reference to the drawings.

In FIG. 2, a motor 1 with a commutator has brushes 2A, 2B, and 2C, and the brush 2A is connected to a motor frame 3 and a DC power source 4.
connected to the negative terminal of The brushes 2B and 2C are for speed switching, and are connected to the positive electrode of a DC power source 4 via a speed changeover switch 5. Here, the chiyoke coil L3 is connected to the ferrite core 1 as shown in FIG.
0, two windings N corresponding to brushes 2B and 2C
1 and N2 are wound independently. Winding N
Since current does not flow through 1 and N2 at the same time,
There is no problem with the winding direction. In order to prevent noise, independent windings N1 and N2 of a chiyoke coil L3 are inserted into the connection lines between the brushes 2B and 2C and the DC power supply 4, respectively, and capacitors C1 and C2 are connected to the lines connected to the brushes 2B and 2C. It is provided between the motor frame 3 and the motor frame 3. In addition, Chiyoke coil L
3 and capacitors C1 and C2 are motor frame 3
It is desirable to provide it as close to the brush as possible within the brush.

As described above, according to the noise prevention structure of the motor with a commutator of the present invention, a plurality of windings corresponding to the number of brushes for speed switching are provided in one magnetic core of the chiyoke coil, and each winding is switched between speeds. By inserting the brushes between the brushes and the power supply, it is possible to reduce the size and cost.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing a conventional noise prevention structure for a motor with a commutator, FIG. 2 is a circuit diagram showing an embodiment of the noise prevention structure for a motor with a commutator according to the present invention, and FIG.
The figure is a perspective view of a chiyoke coil used in the example. 1...Motor with commutator, 2A, 2B, 2C...
Brush, 3...Motor frame, 4...DC power supply, C1, C2...Capacitor, L1, L2, L
3...Chiyoke coil, N1, N2...Winding.

Claims (1)

[Scope of utility model registration request] In a commutator motor equipped with a first brush connected to one electrode of a power source and a plurality of brushes for speed switching connected to the other electrode of the power source, a plurality of windings are formed on one magnetic core. Inserting each winding of the wire-coated coil in series between the plurality of speed switching brushes and the power source,
A noise prevention structure for a motor with a commutator, characterized in that a capacitor is connected between a line connected to the plurality of brushes for speed switching and a line connected to the first brush.