JP2005094924A - DC motor - Google Patents

Abstract

【Task】
The noise canceling element is disposed outside the motor body, and there is a risk of interference with other components and components of the driven part driven by the DC motor. Furthermore, there has been a problem that the effective size of the motor body is increased by disposing the noise canceling element outside. [Solution]
Disposing the noise canceling element between the stators of the DC motor is the first solution, and disposing the noise canceling element between the DC motor housing and the brush holder is the second solution. . That is, by accommodating the noise canceling element in the housing, interference with other components and the effective size of the DC motor are reduced.
[Selection] Figure 1

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 electrically connected to the brush and disposed in a space defined by a plurality of stators and a wall surface of the housing. It is that.

  In order to solve the above-mentioned problems, the technical means taken in the present invention includes a housing having an opening, a plurality of stators fixed at intervals in the housing, and a fixing unit. A brush that holds a brush that is slidable on the armature commutator, disposed in the opening of the housing, and an armature that is rotatable in the housing in a radial direction facing the child, a shaft that outputs the rotation of the armature The DC motor is provided with a noise canceling element which is electrically connected to the holder and the brush and is disposed between the brush holder and the housing.

   According to the first and second aspects of the present invention, since the noise canceling element can be accommodated in the housing of the DC motor, it has no influence on the interference with other components (components) and the structure of the driven part. It has become possible to increase the degree of freedom of design without affecting 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 to 4 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. In this embodiment, an example in which ball bearings are used as the bearings 5 and 7 has been described. However, the present invention is not limited to ball bearings, and any bearing structure having an inner race and an outer race may be used.

  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 fix 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 7 c 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. A pair of brushes 12 is disposed in the recess 8 of the armature 8, and both the brushes 12 are pressed and urged in the direction toward the commutator 11 described with reference to FIG. One end of the terminal TM constituting the power feeding unit is electrically connected to the brushes 12, and the other end of the terminal TM is connected to an external power source. In this embodiment, each terminal TM extends from the brush 12 toward the space S between the two magnets 6 and has a fixed portion TMF to the housing 2 of the terminal TM. It 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. The capacitor C can be fixed to the peripheral wall surface 2d to prevent the peeling from the terminal TM due to the vibration received by the DC brush motor 1.

(Second Embodiment)
FIG. 2 shows a second embodiment of the present invention, and the same parts as those in the first embodiment will be described with the same reference numerals 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 center 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. Further, a spring holder 53 that fixes the 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 for fixing the spring holder 53 to the housing 2 is fitted to the outer peripheral end of the housing 2, and the cover case 54 holds the spring holder 53 and the brush holder 3 in the housing. It functions to fix to 2.

 The spring holder 3 has a flange 3a so as to close the opening 2b of the housing 2, and a concave groove 3b is formed in a part of the surface of the flange 3a facing the cover case 54. 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 brush 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 in which the brush holder 3, the bearing 7, the end plate 50, and the spring holder 53 are removed from the DC motor 1 of FIG. 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, the first and second embodiments have been described, but it is needless to say that the structure can be appropriately changed as long as the gist of the invention described in the claims of the present invention is not changed.

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 sectional drawing which shows 2nd Example of the DC motor of this invention. It is a top view which shows the internal structure by 2nd Example of the direct-current motor of this invention.

Explanation of symbols

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

Claims (2)

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 direct current 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 a wall surface of the housing. A housing having an opening;
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 between the brush holder and a housing.

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