JPH06311708A - Mounting structure for choke coil for suppressing noise of motor - Google Patents

Abstract

PURPOSE:To obtain a noise suppression circuit in small size with a large noise suppression effect by arranging a choke coil by opposing a magnetic field, generated when a current flows in the choke coil, relating to a magnetic field generated by a permanent magnet. CONSTITUTION:A choke coil 20 is arranged between a brush holder 18 and a permanent magnet which is a stator 13, and a magnetic field, which is a magnetic circuit not used for motor driving of the magnetic fields generated by the permanent magnet, is formed as shown by an arrow mark X. A magnetic field, generated when a current flows in the choke coil 20, is generated toward an opposite direction to the magnetic field X, as shown by an arrow mark Y, and the choke coil 20 is arranged so that directions of these magnetic fields X, Y are opposed to each other. As a result, in the magnetic field Y generated in the choke coil 20, a reverse field to the magnetic field X is applied, and even when a large current is generated by increasing a load of a motor 10, since the magnetic field in a core of the choke coil 20 is prevented from being easily saturated, a noise suppression circuit in small size with an excellent noise suppression effect can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a choke coil mounting structure for preventing noise of a motor using a permanent magnet.

[0002]

2. Description of the Related Art In conventional motors,
A technique is known in which a choke coil is used to prevent noise (see, for example, Japanese Utility Model Publication No. 58-21348). However, if the choke coil is simply provided, the core of the choke coil is saturated when a large current is passed, and the noise prevention effect is reduced.

An object of the present invention is to provide a noise prevention circuit structure which is small in size and has a large noise prevention effect.

[0004]

In the motor noise prevention choke coil mounting structure according to the present invention, in a motor having a permanent magnet as a stator, a magnet which is not used for driving the motor is generated by the permanent magnet. The choke coil is arranged such that a magnetic field generated when a current flows through the choke coil is opposed to a magnetic field which is a circuit.

[0005]

In the present invention, since the magnetic field generated when a current flows through the choke coil is opposed to the magnetic field generated by the permanent magnet, which is a magnetic circuit not used for driving the motor, the choke coil is arranged. The magnetic flux in the core of the choke coil is reduced, the load on the motor is increased, and even if a large current flows through the choke coil, the magnetic field in the core of the choke coil is less likely to be saturated. Therefore, even if a large current flows, the noise prevention effect is less likely to decrease. Also, if the same effect is obtained, the size of the coil can be made small.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The members, arrangements, and the like described below do not limit the present invention and can be variously modified within the scope of the gist of the present invention.

1 and 2 show an embodiment according to the present invention. FIG. 1 is an explanatory view of a motor using a mounting structure of a noise-preventing choke coil, and FIG. 2 is an enlarged view of a main part of FIG. It is a figure.

The motor 10 of this example, as shown in FIG.
The stator 13 disposed in the yoke 12 and the armature 1
4, a commutator C attached to the output shaft 11 side of the rotary shaft 16 of the armature 14, an insulator 15 provided with a brush holder 18, and a brush 19 held by the brush holder 18 and slidingly contacting the commutator C. I have it. A pigtail 19a is connected to the brush 19. In FIG. 1, the symbol H indicates a housing.

The armature 14 of this embodiment is formed by winding a coil 14b around an armature core 14a, and a rotating shaft 16
Both ends of the rotating shaft 16 are rotatably supported by bearings 17 (only the opposite output shaft side is shown).

A choke coil 20 is arranged between the brush holder 18 and the permanent magnet which is the stator 13. This choke coil 20 has two lead wires 21 and 21.
2 is formed, one lead wire 21 is connected to the pigtail 19a, and the other one lead wire 22 is connected to a lead wire (not shown). That is, the brush 19 is connected to the lead wire via the pigtail 19a, the lead wire 21, the choke coil 20, and the lead wire 22. The pigtail 19a and the lead wire 21 may be used in combination.

Of the magnetic field generated by the permanent magnet,
The magnetic field, which is a magnetic circuit not used to drive the motor, is shown in FIG.
The inside is formed as shown by an arrow X. The magnetic field generated when a current flows through the choke coil 20 is generated in the direction opposite to the magnetic field X as shown by the arrow Y, and the directions of these magnetic fields X and Y are opposed to each other. Then, the choke coil 20 is arranged.

By arranging the choke coil 20 in this way, a magnetic field Y generated in the choke coil 20 is generated.
Means that the magnetic field generated by the permanent magnet is always opposite to the magnetic field X, which is a magnetic circuit that is not used to drive the motor, and the choke coil is generated even if the load of the motor 10 increases and a large current flows. The magnetic field in the core of 20 becomes hard to be saturated. Therefore, even if a large current flows, the noise prevention effect is less likely to decrease. Further, since the capacitance of the choke coil 20 can be made smaller than in the conventional case, the choke coil 20 which can obtain the same noise prevention effect can be made smaller.

FIG. 3 is an enlarged view of an essential part showing another embodiment. In this embodiment, the same members as those in the above embodiment are designated by the same reference numerals, and the description thereof will be omitted. In this example, the choke coil 2
0 is mounted so as to be placed on the magnetic body 23, and the magnetic body 23 is placed at a lower position of the stator 13 (a position perpendicular to the rotor 14 with respect to the stator 13).
It is fixed by well-known means.

One lead wire 22 of the choke coil 20 is fixed to the insulator 15 by adhesion or the like, and the other lead wire 21 and the pigtail 19a are connected by a fixing member 24. The fixing member 24 is, for example, L-shaped, and one side 24a side is fixed to the insulator 15 by a fixing tool 25 such as a rivet, and the other side 24b side is swaged so as to wrap the lead wire 21 and the pigtail 19a,
Connected.

As in this example, the choke coil 20 is made of a magnetic material.
When attached, the magnetic force of the stator 13 easily flows toward the magnetic body 23 side, and can play a role of assisting the magnetic circuit for the so-called choke coil 20.

[0016]

As described above, according to the present invention, the magnetic field in the core of the choke coil is less likely to be saturated even when the load on the motor increases and the current becomes large, and therefore noise is prevented even when a large current flows. The decrease in the effect is small. Further, if the same effect is obtained, the size of the coil may be small, and it is possible to provide a small-sized noise prevention circuit structure having a large noise prevention effect.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a motor using a noise-preventing choke coil mounting structure according to the present invention.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is an enlarged view of an essential part showing another embodiment.

[Explanation of symbols]

 10 Motor 11 Output Shaft 12 Yoke 13 Stator 14 Armature 14a Armature Core 14b Coil 15 Insulator 16 Rotation Shaft 17 Bearing 18 Brush Holder 19 Brush 19a Pigtail 20 Choke Coil 21, 22 Lead Wire 23 Magnetic Material 24 Fixing Member 24a, 24b Side 25 Fixture C Commutator H Housing X Magnetic field that is a magnetic circuit not used for motor drive Y Magnetic field generated when current flows through the choke coil

Claims (1)

[Claims] 1. In a motor having a permanent magnet as a stator, a magnetic field generated when a current flows through a choke coil is opposed to a magnetic field generated by the permanent magnet, which is a magnetic circuit not used for driving a motor. A choke coil mounting structure for preventing noise of a motor, characterized in that the choke coil is arranged.