JP2005218241A - Small brush motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small brush motor capable of setting a pair of brushes well on a commutator by simply assembling an end lid and a rotor without causing impact deformation or damage on the pair of brushes. <P>SOLUTION: A rotor 50 has a conical brush guide 20 fitted over a motor shaft 5a on the side projecting from an oil return washer 6 and having an annular part 21 for passing the motor shaft 5a, and six sectoral resilient protrusions 22 protruding from the annular part 21 in the direction of a conical generator. When an end lid 7 is fixed to the end opening of a motor case 1, a pair of brushes 7A ride on the protrusion 22 as they are pushed in the thrust direction. After the pair brush 7A extended gradually in the receding direction, the pair of brushes 7A ride over the oil return washer 6 to clamp the circumferential surface of a commutator 5E. Furthermore, the guide 20 is flattened and its diameter is enlarged because an oil impregnation bearing 7e held by the end lid 7 pushes in the annular part 21. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a small motor with a brush, and more particularly to a technique for setting a brush pair to a commutator during motor assembly.

  Conventionally, assembling a small motor with a brush, as shown in FIG. 3, is a bottomed cylindrical motor case with an open end, an oil-impregnated bearing 2, a magnet 3, an adjusting washer (thrust washer) 4, a rotor 5, and an oil return. A washer 6 and an end cover (end bracket) 7 are prepared, the oil-impregnated bearing 2 is press-fitted into the end plate burring portion 1a of the motor case 1, the magnet 3 is attached to the inner peripheral surface of the motor case 1, and the motor shaft 5a is attached. After the adjustment washer 4 is fitted, the motor shaft 5a is inserted into the bearing 2, and after the oil return washer 6 is fitted to the motor shaft 5a, the end lid 7 is attached to the end opening of the motor case 1. Alternatively, the motor case 1 may be fitted after the oil return washer 6 is fitted to the motor shaft 5a and then assembled to the end lid 7.

  Here, as shown in FIG. 4, the rotor 5 is attached around a core 5b made of a laminated magnetic plate, insulating cores 5c and 5c covering both end surfaces of the core 5b, and a commutator holder 5d inserted into the motor shaft 5a. Three commutator pieces 5e, 5e, 5e (commutator 5E) in contact with each other, a fastening ring 5f for fastening these commutator pieces 5e, 5e, 5e (commutator 5E), and around the fastening ring 5f It consists of an attached ring-shaped varistor 5g, an insulating washer 5h, a rotor bush 5i, and a winding (not shown) wound around the core 5b. Further, as shown in FIG. 5, the end plate 7 supports a pair of brush pieces 7a and 7a (brush pair 7A) and is attached to a brush holder 7b for attaching the end plate 7c and a central hole of the end plate 7c. It consists of a thrust bearing 7d and an oil-impregnated bearing 7e.

  When the end cover 7 and the rotor 5 are assembled, as shown in FIG. 6, the brush pieces 7a and 7a (brush pairs 7A) supported by the end plate 7 and in a phase contact state are arranged along the motor shaft 5a. Since the brush pair 7A pushed in the direction of the arrow in FIG. 6 directly contacts the end face of the oil return washer 6 having a diameter larger than the shaft diameter, the end plate 7c is perforated. After inserting a pin tool or the like into the brush expansion adjustment holes A and A and pushing the end lid 7 in a state where the brush pair 7A is pushed and bent toward the brush holder 7b, the pin tool or the like is removed and the brush pair 7A is pulled out. Therefore, the operation of hitting the commutator 5E with the spring property is required.

  However, as the motor becomes smaller (smaller in diameter), it becomes very difficult to provide the end plate 7c with the brush expansion adjustment holes A and A themselves, and the adjustment work of the brush set with a pin tool or the like is complicated. It will be a thing.

  For example, in the end plate 7c that does not include the brush expansion adjusting holes A, A, the oil return washer is forcedly pushed by the operation of simply closing the end lid 7 to the end opening of the motor case 1. Since it is necessary to employ a forcible method of bringing the commutator 5E into contact with the end face side of the spring 6 using the spring reaction deformation, impact deformation or damage or the like occurs in the brush pair 7A. As the brush pair 7A becomes lighter and thinner due to the miniaturization of the motor, impact deformation and damage of the brush pair 7A cannot be ignored. For this reason, the yield of a small motor with a brush is reduced.

  In view of the above problems, the problem of the present invention is that the brush pair can be successfully set on the commutator without the impact deformation or damage of the brush pair only by assembling the end cover and the rotor. It is to provide a small motor with a motor.

  A small motor with a brush according to the present invention includes a rotor in which a commutator is insulatively attached to a motor shaft protruding from an armature, a motor case that incorporates the rotor and is rotatably supported, and an end of the motor case A pair of brushes that are supported by an end cover attached to the opening of the part and are in sliding contact with the commutator; and a bearing that is held by the end cover. According to the present invention, in the process of assembling the end cap and the rotor, there is provided brush guide means for expanding the brush pair in the direction away from each other in accordance with the relative pushing of the brush pair in the thrust direction. .

  In such a configuration, when the end lid and the rotor are mounted, in the mounting process, the brush guide means expands the brush pair in a direction away from each other in response to the pushing of the brush pair in the thrust direction. Gets over without slipping into the end face of the commutator and slides into the peripheral face of the commutator. For this reason, the collision of the brush pair with the end face of the commutator does not occur, and the brush pair can be set on the commutator without difficulty, so that impact deformation or damage of the brush pair can be avoided and the yield can be improved.

  Of course, an oil return washer may be fitted to the end of the commutator in order to perform the oil return carefully. Even in such a case, the brush pair rides over the end face of the commutator without contacting the end face of the oil return washer, so that the brush pair does not collide with the end face of the oil return washer. Therefore, the impact deformation and damage of the brush pair can be avoided, and the yield can be improved.

  The brush guide means may be a cone-shaped brush guide that is externally fitted on the side of the motor shaft protruding from the commutator and gradually increases as the outer diameter approaches the commutator side. In response to the brush pair being pushed in the thrust direction, the brush pair rides on the circumferential surface of the cone, so that the brush pair gradually expands away from each other, and then the restoring force of the brush pair causes the brush pair to Insert the circumference.

  However, since this cone-shaped brush guide is tapered and has a thickness in the axial direction, there is a disadvantage that the motor shaft length becomes slightly longer.

  Therefore, in the present invention, it is desirable that the cone-shaped brush guide body has a transformation property that is flattened and expanded in diameter by being pressed by the bearing in the process of attaching the end cover to the end opening of the motor case. . When the end cover is completely installed, the cone-shaped brush guide body is flattened in the axial direction, but the outer diameter is increased, so the axial length is not increased, and the cone-shaped brush guide body Since the outer diameter is larger than the outer diameter of the commutator and can be equal to or greater than the outer diameter of the oil return washer, the oil return function can be achieved only with the cone-shaped brush guide without the oil return washer. .

  This conical brush guide can be crowned in a free state. That is, the cone-shaped brush guide body includes an annulus through which the motor shaft passes and a plurality of elastic protrusions that protrude from the discrete points around the annulus in the direction of the cone bus. Since such a cone-shaped brush guide body can be configured as one part by press molding or resin molding, the labor of the assembling process does not increase, and the cost can be reduced.

  Since the present invention has the brush guide means, the brush pair can be successfully set on the commutator without any impact deformation or damage of the brush pair only by attaching the end cover to the end opening of the motor case. .

  Next, embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1A is a perspective view showing a configuration of a rotor in an embodiment of the present invention, and FIG. 1B is a perspective view showing a cone-shaped brush guide used in the embodiment.

  Since the small motor with a brush of this example also has the structure shown in FIG. 3 in general, its description is omitted, but the structure of the rotor is different. That is, as shown in FIG. 1A, the rotor 50 of this example has a cone-shaped brush guide body 20 that is externally fitted on the side of the motor shaft 5a that protrudes from the oil return washer 6. The cone-shaped brush guide body 20 is a crown-shaped resin molded product, and as shown in FIG. 1B, an annular portion 21 through which the motor shaft 5a passes and a surrounding 6-segment dividing point. It has six divergent elastic projecting pieces 22 projecting in the direction of the cone bus. In this example, the outer diameter of the end of the divergent elastic protruding piece 22 in the natural state is substantially equal to the oil return washer 6.

  When the end lid 7 and the rotor 50 are assembled, the brush pair 7A shifts from the state shown in FIG. 2A to the state shown in FIG. 2B, and the brush pair 7A corresponds to the pushing of the brush pair 7A in the thrust direction. 2A and 2B, after the brush pair 7A gradually expands in the direction away from each other, the resting force of the brush pair 7A is restored as shown in FIG. Thus, the brush pair 7A passes over the oil return washer 6 and sandwiches the circumferential surface of the commutator 5E. At the end of the transition of the brush pair 7A from the state of FIG. 2 (B) to FIG. 2 (C), the oil-impregnated bearing 7e held by the end lid 7 pushes the ring portion 21 of the cone-shaped brush guide body 20; The divergent elastic projecting piece 22 is bent from the root of the ring portion 21, and the cone composed of the divergent elastic projecting piece 22 is flattened and enlarged in diameter.

  For this reason, at the end of pushing in the end lid 7, the end of the divergent elastic protruding piece 22 protrudes to the outer peripheral side of the outer diameter of the oil return washer 6 and the umbrella is opened, so that the brush pair 7 </ b> A is placed on the end face of the oil return washer 6. After sufficiently getting over without contact, it comes into close contact with the commutator 5E. Accordingly, the brush pair 7A can be successfully set on the commutator 5E without causing impact deformation or damage of the brush pair 7A, and the axial thickness can be suppressed. In addition, the oil return effect is exhibited only with the cone-shaped brush guide body 20 without using the oil return washer 6.

(A) is a perspective view which shows the structure of the rotor in the Example of this invention, (B) is a perspective view which shows the substantially conical brush guide body used in the Example. (A) is a perspective view showing the relationship between a brush pair and a commutator when the end cover is mounted in the embodiment, and (B) is a perspective view showing a state in which the brush pair is guided by a substantially conical brush guide body. FIG. 4C is a perspective view showing a state where the brush pair is positioned on the commutator. It is an assembly perspective view which shows the conventional small motor with a brush. It is an assembly perspective view of the rotor in the conventional example. It is an assembly perspective view of the end lid in the conventional example. It is a perspective view which shows the relationship between the brush pair and commutator at the time of mounting | wearing with an end cover in the prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Motor case 1a ... End plate burring part 2, 7e ... Oil-impregnated bearing 3 ... Magnet 4 ... Adjustment washer (thrust washer)
5, 50 ... Rotor 5a ... Motor shaft 5b ... Core 5c ... Insulating core 5d ... Commutator holder 5e ... Commutator piece 5E ... Commutator 5f ... Ring ring varistor 5h ... Insulating washer 5i ... Rotor bush 6 ... Oil Return washer 7 ... end lid (end bracket)
7A ... Brush pair 7a ... Brush piece 7b ... Brush holder 7d ... Thrust bearing 20 ... Conical brush guide 21 ... Ring 22 ... Diverging elastic protrusion A ... Adjustment hole for brush expansion

Claims (6)

Supported by a rotor in which a commutator is insulatively attached to a motor shaft protruding from an armature, a motor case that incorporates the rotor and is rotatably supported, and an end lid that is attached to an end opening of the motor case. A brush-type small motor having a brush pair for sliding contact with the commutator and a bearing held by the end cover,
In the process of assembling the end lid and the rotor, the brush has a brush guide means for expanding the brush pair in a direction away from each other in accordance with the relative pressing of the brush pair in the thrust direction. With a small motor. A rotor in which a commutator is insulatively attached to a motor shaft protruding from an armature, and an oil return washer is inserted at an end of the commutator, a motor case that incorporates the rotor and is rotatably supported, and the motor case A brushed small motor having a brush pair that is supported by an end lid attached to an end opening of the brush and that is in sliding contact with the commutator, and a bearing held by the end lid,
In the process of assembling the end lid and the rotor, the brush has a brush guide means for expanding the brush pair in a direction away from each other in accordance with the relative pressing of the brush pair in the thrust direction. With a small motor. The brush guide means according to claim 1 or 2, wherein the brush guide means is a cone-shaped brush guide body that is externally fitted to a side of the motor shaft protruding from the commutator and gradually increases as the outer diameter approaches the commutator side. A small motor with a brush characterized by being. 4. The small motor with brush according to claim 3, wherein the cone-shaped brush guide body has a transformation property of being flattened and enlarged in diameter by being pressed by the bearing during the pushing-in process. 5. The small motor with a brush according to claim 4, wherein the cone-shaped brush guide body has a crown shape in a free state. 6. The cone-shaped brush guide body according to claim 5, wherein the cone-shaped brush guide body includes a ring portion through which the motor shaft passes, and a plurality of elastic protruding pieces each protruding in a direction of a cone bus line from discrete points around the ring portion. A small motor with a brush that makes up.

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