JP4438362B2 - DC motor - Google Patents

Description

  The present invention relates to a DC brush motor driven by a DC current, and more specifically, is a small and thin DC motor mounted on a vehicle and suitable as a driving source for an anti-skid brake system or a traction system, and noise elimination. The present invention relates to a motor provided with an element.

  As a conventional DC motor of this type, one disclosed in Japanese Patent Application Laid-Open No. 2001-8414 (Patent Document 1) is known.

  Conventionally, a capacitor for erasing noise is provided in a DC motor, and a capacitor as a noise erasing element is directly connected to a terminal of the motor, or a motor terminal and a substrate on which a noise erasing element is arranged. It was the structure connected via a harness.

Patent Document 1 shows a configuration in which a noise canceling element is disposed on an outer peripheral surface on a brush holder disposed in an end frame.
Japanese Patent Laid-Open No. 2001-8414 (see FIG. 3)

  However, the conventional type or the configuration of the DC motor disclosed in Patent Document 1 has a structure in which the noise canceling element is disposed outside the motor body, and other components and driven parts that are driven by the DC motor. There was a risk of interference with other components. Further, there is a problem that the effective size of the motor body is increased by disposing the noise canceling element outside.

  It is a technical object of the present invention to provide a DC motor having a novel structure in which a noise canceling element does not interfere with other components and can be further reduced in size.

In order to solve the above-mentioned problems, the technical means taken in the present invention includes a bottomed housing having an opening at one end and a plurality of fixed members spaced at intervals in the housing. Stator, armature that is radially opposed to the stator and rotatable within the housing, a shaft that outputs the rotation of the armature, and an opening of the housing that is slidable on the commutator of the armature A direct current motor comprising a brush holder for holding a brush, and a noise canceling element that is electrically connected to the brush and disposed in a space defined by a plurality of stators and an inner wall surface of the housing. It is that.

According to the first aspect of the present invention, since the noise canceling element can be accommodated in the housing of the DC motor, it interferes with other components (components) and has no influence on the structure of the driven part. It is now possible to increase the degree of design freedom without any problems. In particular, the fact that the configuration on the DC motor side does not affect the structural configuration of the driven part has the effect of enhancing the versatility of the DC motor.

Hereinafter, the best mode for carrying out the present invention will be described with reference to FIGS. 1 and 2 by taking a DC motor as an example.

(First embodiment)
As shown in FIG. 1, the housing 2 of the DC motor 1 (DC brush motor) has an opening 2a at one end and the bottomed portion 2b (bottomed) at the other end. The housing 2 is formed by molding a metal plate material, and also functions as a yoke when configuring the magnetic circuit of the DC motor 1. A brush holder 3 serving as an end plate is disposed so as to cover the opening 2a. A bent portion 2c that rises toward the opening 2a is formed on the bottomed portion 2b by a press or the like, and a bearing 5 that rotatably supports a shaft 4 that is an output shaft of the DC motor 1 (forms a first bearing). Is arranged. The bent portion 2c is formed by press-molding the housing 2, but it is also possible to support the bearing 5 by directly fixing the bearing member to the housing 2.

  The brush holder 3 is made of resin and has the same outer shape as the opening of the housing 2. In the central part 3a of the brush holder 3, a bearing 7 (forming a second bearing) that supports the shaft 4 is disposed. The bearing 7 includes an inner race 7a, a ball bearing 7b, an outer race 7c, and a mechanical seal 7d. Although the example which used the ball bearing as the bearings 5 and 7 was demonstrated in the present Example, it is not limited to a ball bearing, A bearing structure will not ask | require if it is a bearing structure which has an inner and an outer race.

  A plurality of magnets 6 functioning as stators are fixed along the peripheral wall surface 2d in the internal space of the housing 2, and the axial length of the magnets 6 is substantially the same as the internal dimension of the housing 2 in the axial direction. Is set. In this embodiment, four magnets 6 are disposed in the housing 2, and a space S defined by the two stators and the peripheral wall surface 2 d of the housing 2 is formed. In the space S, a capacitor C that functions as a noise canceling element electrically connected to a brush 12 described later is disposed.

  The brush holder 3 is fitted in the housing 2 and defines an internal space 1 a of the DC motor 1. An armature 8 is supported by bearings 5 and 7 so as to rotate together with the shaft 4 in a space in the housing 2 surrounded by the magnet 6. The armature 8 includes a core 9 (movable element) and an armature coil 10. In this embodiment, the core 9 is formed of a laminated iron plate, but it can also be formed of a molded body of soft magnetic powder. A concave portion 8 a is formed on the surface of the armature 8 fixed to the shaft 4, facing the brush holder 3, and in the substantially central portion thereof, that is, around the axis of the armature 8. A commutator 11 electrically connected to the armature coil 10 is disposed on the inner wall surface of the recess 8a. A brush 12 is disposed in the recess 8a so as to face the commutator 11 and be slidable with respect to the commutator 11. Therefore, the commutator 11 and the brush 12 are located within the axial length of the magnet 6 and the armature 8.

  In this embodiment, the brush 12 is held by a flange 3c that extends into the recess 8a of the armature 8 of the brush holder 3. The brush 3 can hold and hold the brush 12 so as to face the commutator 11 on the flange 3c. A hole 3d is formed.

  The shaft 4 of the DC motor 1 is drivingly connected to a driven part, for example, a driving mechanism 20 of an anti-skid brake system or a traction system, and has a mounting flange 2e formed in an opening of the housing 2 and a brush. The holder 3 is fixed so as to be in direct contact with the housing body 21 of the driven part.

  A groove 7e is formed on the outer peripheral surface of the outer race 7c of the bearing 7 disposed on the flange 3c of the brush holder 3. After the bearing 7 is assembled to the brush holder 3, a fastener 13 is formed in the groove 7e. It is fitted and functions to fix the bearing 7. The fastener 13 is sandwiched between the brush holder 3 and the housing body 21 of the driven part. In this embodiment, a C-ring is used as the fastener 13, but other means can be used as appropriate as long as the outer race 7c of the bearing 7 is fixed.

FIG. 2 is a plan view in which the brush holder 3, the bearing 7, and the drive mechanism 20 are removed from the DC motor of FIG. The in the recess 8 a of the armature 8 a pair of brushes 12 is disposed, both the brush 12 is pressed and urged in the direction of the commutator 11 described in FIG. 1 by the spring SP. One end of a terminal TM constituting the power feeding unit is electrically connected to both brushes 12, and the other end of the terminal TM is connected to an external power source. For each terminal TM this embodiment, extends toward the space S between the brush 12 of the two magnets 6 has a fixed portion TMF to the housing 2 of the terminal TM, the capacitor C on both fixed part TMF Is connected. As described above, the capacitor C is disposed in the space S formed by the two magnets 6 and the peripheral wall surface 2 d of the housing 2. Note that the capacitor C can be fixed to the peripheral wall surface 2d to prevent the peeling from the terminal TM due to the vibration that the DC brush motor 1 receives.

FIG. 3 shows another embodiment, and the same parts as those in the first embodiment are described with the same numbers and symbols in principle.

  As shown in FIG. 3, the housing 2 of the DC motor 1 has an opening 2 a at one end and an opening 2 b at the other. The housing 2 is formed by molding a metal plate material, and also functions as a yoke when configuring the magnetic circuit of the DC motor 1. An end plate 50 made of metal (made of iron in this embodiment) serving as an end plate is disposed so as to cover the opening 2a. A resin brush holder 3 having a substantially concave shape is disposed in the opening 2b so as to cover the opening 2b.

  A plurality of magnets 6 functioning as stators are fixed along the peripheral wall surface 2d in the internal space of the housing 2, and the axial length of the magnets 6 is substantially the same as the internal dimension of the housing 2 in the axial direction. Is set. In this embodiment, four magnets 6 are arranged in the housing 2.

  An armature 8 (rotor) is supported by a bearing 7 so as to rotate together with the shaft 4 in a space in the housing 2 surrounded by the magnet 6. The armature 8 includes a core 9 (movable element) and an armature coil 10. The core 9 can be formed of a laminated iron plate or a soft magnetic powder compact. The core 9, the shaft 4, and the commutator 11 that is in sliding contact with the brush 12 described later are integrally molded with a resin. Serrations are formed on the surface of the shaft 4 so that the joint strength with the shaft 4 becomes a practical strength. A recess 51 is formed in the central portion of the armature 8, and the brush holder 3 is accommodated in the recess 51.

The brush 12 is disposed in the central portion of the brush holder 3, and the brush 12 is pressed and urged so as to be in sliding contact with the commutator 11 by a contracted coil spring 52. A spring holder 53 that fixes the coil spring 52 disposed in the brush holder 3 and closes the opening of the brush holder 3 is disposed. The spring holder 53 includes a flange 53 a for fixing the coil spring 52 that biases the brush 12. Further, a cover case 54 constituting a part of the housing 2 for fixing the spring holder 53 to the housing 2 is fitted to the outer peripheral end portion of the housing 2, and the cover case 54 connects the spring holder 53 and the brush holder 3. It functions to be fixed to the housing 2.

Brush holder 3 has a flange 3a so as to close the opening 2b of the housing 2, it is formed with a recessed groove 3b Some face you face the cover case 54 of the flange 3a. A capacitor C functioning for noise removal and electrically connected to the brush 12 is disposed in the concave groove 3b. The capacitor C is pressed against the brush holder 3 by the extended portion 53 b of the spring holder 53. Since the extended portion 53 b of the spring holder 53 is also positioned by the cover case 54 located at the outermost contour, the capacitor C is fixed in the concave groove 3 b formed in the brush holder 3.

4 shows a plan view of the DC motor 1 shown in FIG. 3 with the cover case 54 and the spring holder 53 removed. A capacitor C functioning as a noise canceling element is disposed in the concave groove 3b formed in the brush holder 3.

  The capacitor C is electrically joined to a part of the wire W that electrically connects the brush 12 and the terminal TM.

As described above, it has been described first embodiment and other forms, as long as they do not change the gist of the invention described in claims of the present invention, that the structure may be appropriately changed course.

It is sectional drawing which shows 1st Example of the DC motor of this invention. It is a top view which shows the internal structure by 1st Example of the direct-current motor of this invention. It is a cross-sectional view showing another embodiment of the dc motor. Is a plan view showing an internal structure according to another embodiment of the dc motor.

2 Housing 6 Stator 8 Armature
4 Shaft 3 Brush holder S space C Noise canceling element

Claims (1)

A bottomed housing having an opening at one end;
A plurality of stators fixed at intervals in the housing;
An armature rotatable in the housing opposite to the stator in a radial direction;
A shaft that outputs the rotation of the armature;
A brush holder that holds a brush that is arranged in the opening of the housing and is slidable on the commutator of the armature;
A DC motor comprising a noise canceling element that is electrically connected to the brush and disposed in a space defined between the plurality of stators and an inner wall surface of the housing.

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