JP2005051962A - Dc motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new structure that makes it possible to thin the length in axial direction, i.e. the thickness, of a DC motor, and that makes it possible to reliably support the shaft of the DC motor rotatably on the motor. <P>SOLUTION: This DC motor is made up of a housing 2; a stator 6 fixed inside the housing 2; an armature 8 that rotates freely inside the housing 2; the shaft 4 that outputs rotations of the armature 8; a first bearing 5 that supports the shaft rotatably; a brush holder 3 that holds a brush 12 slidably on the commutator 11 of the armature 8 arranged at an opening 2a of the housing 2; and a second bearing 7 that supports the shaft rotatably. A fastener that fixes the outer race of the second bearing to its inner race is provided on the outer race. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a direct current brush motor driven by direct current, and more particularly to a small and thin direct current motor mounted on a vehicle and suitable as a drive source for an anti-skid brake system or a traction system.

  As a conventional DC motor of this type, the one described in Patent Document 1 described below is known.

  In this conventional DC motor, the case 2 of the DC brush motor 1 is composed of a case body 2a that also serves as a yoke, and an end plate 2b that covers the open side of the case body 2a. The case body 2a is formed in a bottomed cylindrical shape, and a cylindrical bent portion 3 is formed in the center so as to extend inward in the axial direction. A stepped portion 3 a and a small diameter portion 3 b are formed at the tip of the bent portion 3. Of the two bearings 6a and 6b that support the shaft 5 of the armature 4, one bearing 6a disposed on the side close to the brush described later is fitted and fixed to the small diameter portion 3b. The end plate 2b has a structure in which a cylindrical bearing support portion 7 that supports the bearing 6b is bent at the center so as to be bent toward the inside of the case 2, and the bearing 6b is fitted and fixed to the bearing support portion 7.

However, in this conventional DC motor configuration, the end plate 2b is configured to cover the release side of the case body 2a, and the axial length of the DC motor, that is, the thickness of the DC motor is equal to the end plate 2b. It had the problem of becoming thick only. Further, a process is required in which a bearing support portion 7 serving as a receiving side of the bearing 6b that supports the shaft 5 output from the end plate 2b must be formed on the end plate by pressing or the like. It was an influence.
JP 2001-86719 A (see FIG. 1)

  The present invention provides a novel structure in which the axial length of a DC motor, that is, the thickness of the DC motor can be reduced, and the shaft of the DC motor can be securely supported by the motor. Technical issue.

  The technical means taken in the present invention to solve the above-mentioned problems are as described in claim 1 and include a bottomed housing having an opening at one end, a stator fixed in the housing, An armature that is rotatable in the housing in a radial direction facing the stator, a shaft that outputs rotation of the armature, a first bearing that pivotally supports the shaft with respect to a bottom of the housing, and A brush holder that is disposed in an opening of the housing and holds a brush slidable on the commutator of the armature; a second bearing disposed on the brush holder that rotatably supports the shaft; The second bearing has at least an inner race and an outer race, and is a DC motor characterized in that a fastener for fixing the outer race to the inner race is disposed on the outer race.

  Preferably, as described in claim 2, the fastener is a C-ring.

 Preferably, as described in claim 3, the brush holder disposed in the opening of the housing is made of resin, and is fitted into the housing so as to close the opening.

  Preferably, as described in claim 4, it is preferable that a circular concave portion is formed around an axis on one side surface of the armature, and the brush is disposed in the concave portion.

  Preferably, as described in claim 5, the brush holder has a flange portion extending outward from the opening, and a protrusion that can contact the fastener is formed on the flange portion. Le is good.

  Preferably, as described in claim 6, the protrusion is formed on the entire flange portion.

According to the first aspect of the present invention, since the brush holder is a part of the housing of the DC motor by arranging the brush holder in the opening of the DC motor, the thickness of the DC motor can be reduced. There is an effect. Further, by providing the fastener for fixing the outer race of the second bearing to the inner race, the second shaft can be reliably fixed to the brush holder constituting the outer shell of the DC motor main body by the fastener. That is, there is an effect that the DC motor can be established as a single component regardless of the structure of the structure with the driven part to which the DC motor is attached.
According to the second aspect of the present invention, since the bearing can be fixed by the C ring which is a general-purpose part, a reliable fastener structure of the bearing can be obtained without causing a significant cost increase.

 According to the invention of claim 3, since the brush holder is made of a resin material, the entire structure for holding the second bearing can be easily manufactured by resin molding, and the structure change can be flexibly dealt with. is there.

 According to the fourth aspect of the present invention, since the brush holder can be disposed in the recess of the armature (the recess inward in the axial direction), the thickness of the DC motor can be reduced.

 According to the fifth aspect of the present invention, the brush holder has a flange portion extending outward from the opening, and the flange portion has a protrusion capable of contacting the fastener, so that the DC motor is driven. When attached to the part, there is an effect that the contact part between the protrusion and the fastener is deformed to fill the clearance (backlash) between the DC motor and the driven part.

 According to the sixth aspect of the present invention, since the protrusion formed on the flange portion of the brush holder is formed on the entire circumference, the clearance (backlash) between the DC motor and the driven portion can be filled uniformly. There is an effect that the inclination of the shaft is suppressed and the driving force to the driven part does not cause a loss.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  (First Embodiment) As shown in FIG. 1, the housing 2 of the DC brush motor 1 has an opening 2a at one end and the bottomed portion 2b (bottomed) at the other end. The housing 2 is made of metal and functions as a yoke when the magnetic circuit of the DC motor 1 is configured. A brush holder 3 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 (forming a first bearing) that supports the shaft 4 that serves as the output shaft of the DC motor 1 is disposed. Has been. The bent portion 2c is formed by press-molding the housing 2, but it is also possible to support the bearing 5 by fixing a 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. A flange 3b extending in the axial direction of the DC motor 1 is formed in the central portion 3a of the brush holder 3, and a bearing 7 (forming a second bearing) that supports the shaft 4 is disposed on the flange 3b. 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 a ball bearing is used as a bearing has been described. However, the present invention is not limited to a ball bearing, and any bearing structure may be used as long as it has an inner race and an outer race.

  A magnet 6 is fixed in the internal space of the housing 2 along the peripheral wall surface 2d, and the axial length of the magnet 6 is set to be substantially the same as the internal dimension of the housing 2 in the axial direction. The inner space 1 a of the DC motor 1 is defined by fitting with the housing 2. An armature 8 is disposed together with the shaft 4 so as to be integrally rotatable in a space in the housing 2 surrounded by the magnet 6. The armature 8 includes a core 9 (stator) 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 on 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 has a flange 3c having a diameter extending in the recess 8a in the shaft 4 in the direction of the armature 8 of the brush holder 3, and the commutator 11 is disposed on the circumference thereof. A brush holding hole 3d capable of accommodating and fixing the brush 12 is formed.

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

  A concave groove 7e is formed on the outer peripheral surface of the outer race 7c of the bearing 7 disposed on the flange 3b of the brush holder 3. After the bearing 7 is assembled to the brush holder 3, a fastener 13 is formed in the concave groove 7e. It is fitted and functions to fix the bearing 7. The fastener 13 is disposed so as to be sandwiched between the flange 3b of the brush holder 3 and the housing 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.

  (Second Embodiment) FIG. 2 shows a second embodiment of the present invention, in which the same reference numerals are assigned to the same parts. Since the configuration different from the first embodiment is only the configuration of the flange portion 3b of the brush holder 3, only the different portions will be described below.

  The flange 3 b of the brush holder 3 is formed with a protrusion 3 e that protrudes toward the fastener 13 fitted to the outer race 7 c of the bearing 7. When the fastener 13 is fitted to the outer race 7c, the protrusion 3e comes into contact with the fastener 13, and when the DC motor 1 is attached to the housing 21 of the driven portion, the tip of the protrusion 3e is deformed. Thus, it functions to absorb the mounting play between the DC motor 1 and the driven part. In FIG. 2, it is shown that the cross-sectional shape of the protrusion 3 e is a triangle, but it may be a shape having a curvature (so-called circle or ellipse), and the DC motor 1 is attached to the driven portion, The shape is not limited as long as it can be deformed. Further, the protrusion 3e may be formed over the entire circumference on the flange 3b of the brush holder 3, or may be formed on the flange 3b at an appropriate interval. In addition, by forming the protrusion 3e over the entire circumference, when the DC motor 1 is attached to the driven part, there is an effect that the mounting play generated between the two can be absorbed over the entire circumference.

  In addition, although it is a matter common to 1st, 2nd Example, the length between the bottom face of 3e of the brush holder 3 in which the bearing 7 is accommodated, and the flange 3b is from the left end part of the outer race 7c to the left end surface of the fastener 13. Less than the length of. In addition, the DC motor 1 is attached to the non-driving portion by making the distance between the end of the non-driving portion housing 21 abutting against the fastener 13 and the housing 21 abutting against the brush holder 3 smaller than the thickness of the fastener 13. It is possible to fix both firmly.

  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 sectional drawing which shows 2nd Example of the DC motor of this invention.

Explanation of symbols

2a Opening 2 Housing 6 Stator 8 Armature 4 Shaft 5 Bearing (first bearing)
11 Commutator 12 Brush 3 Brush holder 7 Bearing (second bearing)
7a Inner race 7c Outer race 13 Fastener 8a Recess 3e Projection

Claims (6)

A bottomed housing having an opening at one end;
A stator fixed 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 first bearing that pivotally supports the shaft with respect to the bottom of the housing;
A brush holder for holding a brush that is arranged in the opening of the housing and is slidable on the commutator of the armature;
A second bearing disposed on the brush holder that rotatably supports the shaft;
The DC motor according to claim 1, wherein the second bearing has at least an inner race and an outer race, and a fastener for fixing the outer race to the inner race is disposed on the outer race.   The DC motor according to claim 1, wherein the fastener is a C-ring.   The DC motor according to claim 1, wherein the brush holder disposed in the opening of the housing is made of resin and is fitted into the housing so as to close the opening.   The DC motor according to claim 1, wherein a circular recess is formed around an axis on one side of the armature, and the brush is disposed in the recess.   3. The DC motor according to claim 2, wherein the brush holder has a flange portion extending outward from the opening, and a protrusion capable of contacting the fastener is formed on the flange portion.   The DC motor according to claim 5, wherein the protrusion is formed on the entire flange portion.

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