JP2017005934A - DC motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable closed type motor in which much brush wear powder accumulates, that is able to inhibit insulation failure resulting from scattering of brush wear powder into the motor.SOLUTION: A DC motor 1 comprises: a yoke 2; a magnet holder 4 provided on the inner peripheral side of the yoke; a rotary armature having an armature coils 7, armature core 6 and a commutator 12; a brush device 9 that supplies power in slide contact with the commutator; and a brush holder mounting base 11, made of a resin, holding the brush device. The magnet holder fits on the brush holder mounting base. In the magnet holder, the end part on the side that fits on the brush holder mounting base has a projection part projecting radially outside via a step 14, the projecting part composing a brush wear powder pool in which brush wear powder accumulates.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a motor structure that suppresses an electrical short circuit due to a decrease in insulation resistance caused by brush wear powder in a DC motor.

  The following two prior art documents will be described as background art in this technical field.

  In Japanese Patent No. 5001699 (Patent Document 1), a step portion is provided in a resin brush holder, on the bearing side on the inner peripheral surface of the step portion, a small diameter portion close to the commutator, and adjacent to the brush side of the small diameter portion, It is composed of a large-diameter portion that is larger than the small-diameter portion and is separated from the commutator, and a receiving portion is formed from the difference in diameter between the small-diameter portion and the large-diameter portion. An inner wall portion extending to the side is provided, and the inner wall portion is connected to a side surface of the brush housing portion adjacent to the one end portion side and between the other end portion side to the brush housing portion adjacent thereto. It is provided so as to have an interval. By adopting this configuration, brush wear powder adherence to a conductive portion such as a motor housing is prevented to suppress a decrease in insulation resistance.

  Japanese Patent Application Laid-Open No. 2002-58196 (Patent Document 2) includes a cut portion at a portion of the housing opening end facing the brush holder, and has a length at which the tip of the brush holder reaches the housing cylindrical portion at the cut portion. It is configured in such a manner that a partition wall as an insulating member is provided at a circumferential edge opposite to the brush holder of the excision part, or further, there is an inlay part that forms an arc shape in the fitting part with the casing of the lid body The inlay portion is configured to have a taper portion having a gradient of at least 30 degrees on the outer peripheral surface fitted to the housing. By adopting this configuration, it is intended to suppress deterioration of insulation inside the motor due to accumulation of brush wear powder.

Japanese Patent No. 5001699 JP 2002-58196 A

  In recent years, motors used in automobile electrical components are required to be small and have high output in order to improve mountability. In addition, the motor operating time tends to increase significantly compared to the conventional case, and the brush wear powder staying in the motor machine also tends to increase. For this reason, countermeasures against defects (insulation deterioration, noise, etc.) due to brush abrasion powder accumulated inside the motor are urgently needed. Specifically, the brush wear powder of a DC motor contains a copper material in its components, and the wear powder accumulates inside the motor, particularly around the brush, thereby contacting a conductive member such as a motor yoke or an output shaft, This is an event in which noise is generated by an insulation failure such as a short circuit or a spark, and is a problem to be solved to ensure the reliability of the motor.

  Patent Document 1 describes a structure of a brush-around part in which an inner wall is provided in the vicinity of the brush housing portion and the accumulated brush wear powder does not come into contact with the conductive portion as a countermeasure against insulation deterioration of the motor.

  However, in the structure of Patent Document 1, once generated abrasion powder of the brush rises due to the wind pressure due to the rotation of the armature, there is a possibility that the abrasion powder enters the gaps in the inner wall and accumulates in the gaps. There are problems such as complicated surrounding structure, deterioration of workability, and physique.

  Patent Document 2 describes a structure that prevents an insulation deterioration by providing an opening in a housing and discharging brush wear powder therefrom.

  However, in the case of a hermetically sealed motor, there are concerns about the inability to provide an opening and the occurrence of problems due to the entry of foreign matter from the opening.

  Accordingly, an object of the present invention is to provide a highly reliable motor capable of suppressing insulation failure caused by scattering of brush wear powder into the motor in a sealed motor where much brush wear powder remains in the motor. To do.

  In order to solve the above problems, for example, the configuration described in the claims is adopted.

  The present application includes a plurality of means for solving the above-mentioned problems. For example, a rotary electric machine having a yoke, a magnet holder provided on the inner peripheral side of the yoke, an armature coil, an armature core, and a commutator. A DC motor comprising: a child; a brush device that supplies power while slidingly contacting the commutator; and a resin brush holder mounting base that holds the brush device, wherein the magnet holder is mounted on the brush holder The magnet holder has a protruding portion that protrudes radially outward through a step, and the protruding portion is a brush wear powder. It is characterized in that it constitutes a brush wear powder puddle in which water accumulates.

  According to the present invention, it is possible to provide a highly reliable motor that can suppress insulation failure caused by scattering of brush wear powder into the motor in a sealed motor where much brush wear powder remains in the motor.

  Problems, configurations, and effects other than those described above will become apparent from the description of the following examples.

DC motor configuration diagram Magnet holder external view Parts layout around brush

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a configuration diagram of a DC motor according to the present embodiment. The DC motor 1 has a field component including a yoke 2, a magnet 3, and a magnet holder 4, and an excitation component including an output shaft 5, an armature core 6, and an armature coil 7. Further, the power source terminal 8 for drawing in the external power source, the brush 9, the brush holder 10, the brush holder mounting base 11 for fixing the brush holder 10, the commutator 12, and the front plate 13 are used.

  The annular magnet holder 4 made by resin molding has a structure in which the end surface on the brush side is extended and fitted to a brush holder mounting base 11 also made by resin molding. Further, the extension part of the magnet holder 4 is provided with a step in the vicinity of the brush part, and is configured to be thicker by one step (in other words, the extension part protrudes radially outward through the step). The yoke 3 is also provided with a step corresponding to the step shape of the magnet holder 4, and these two parts are assembled in close contact.

  The direct current motor of this embodiment has a horizontal motor orientation and a horizontal mounting state. Therefore, the brush wear powder generated by the sliding contact of the brush is caused by the rotation of the armature core 6. It floats up inside the motor and floats. However, when the rotation of the armature core 6 stops, it accumulates on the lower part of the motor (particularly near the brush) due to its own weight drop.

  Here, particularly in the vicinity of the brush, it accumulates in the space (brush wear dust pool) created by the step provided in the yoke 2 and the magnet holder 4 described above, and therefore it is in contact with the conductive parts such as the brush 9 and the brush lead wire 17. Can keep the distance.

  Further, since the magnet holder 4 molded from the resin as the insulating material exists on the inner diameter side of the yoke 2 as the conductive material, the insulating distance is secured.

  FIG. 2 is an external view of the magnet holder 4. The magnet holder 4 has a structure in which a step 14 is provided in the middle of the axial direction and two pipes having different diameters are combined. In this embodiment, the magnet holder 4 is made by resin molding.

  On the narrower diameter side, magnet insert holes (grooves) 15 are provided by the number of magnets, and they are arranged in the circumferential direction. By setting the magnet 3 in the magnet insert hole (groove) 15, the magnet 3 can be positioned in the axial direction and the radial direction.

  On the end face with the larger diameter, a convex portion or a concave portion 16 for fitting with the brush holder mounting base 11 is provided. A brush holder 10 is set on the brush mounting base 11. By simply fitting the magnet holder 4 and the brush holder mounting base 11 together in a groove 19 (details will be described later) of the brush holder mounting base 11 so as to become an inlay with the convex portion or the concave portion 16 as a reference, these relative positions can be obtained. The position can be assembled with high accuracy. In the multi-pole motor, the deviation between the position of the brush 9 and the position of the magnet 3 greatly affects the performance, and this method has an effect of suppressing the performance variation. Further, since the brush holder mounting base 11 also uses an insulating material, the brush periphery is completely covered with the insulating material, so that it is electrically insulated from the yoke 2 made of a conductive material. As a result, even if brush wear powder accumulates, these insulating materials (the magnet holder 4 and the brush holder mounting base 11) are interposed between the yoke 2 which is a conductive portion, so that electrical defects such as a short circuit are prevented. It becomes possible to do.

  FIG. 3 is an external view of the brush holder mounting base as viewed from the brush holder mounting side (left side in FIG. 1).

  The brush holder mounting base 11 is a resin molded part, and a brush holder 10 integrally molded with a resin is disposed on the upper surface thereof, and a brush 9 is set inside the brush holder. The brush 9 is connected to a terminal 18 which is insert-molded on the brush holder mounting base 11 via a brush lead wire 17. The terminal 18 is connected to the + side and − side of the brush and a terminal for drawing in an external power source. It also has the role of wiring to the connector. Further, the outer peripheral portion of the brush holder mounting base 11 is provided with a groove 19 for fitting with the magnet holder 4 and a positioning projection or hole 20 so that the magnet 3 can be simply assembled by assembling the magnet holder 4 and the brush mounting base 11. Since the radial position of the brush 9 is determined, the positioning operation of the magnet 3 and the brush 9 is not necessary.

  A guide plate 21 for guiding the brush wear powder to the brush wear dust pool is provided below the brush holder mounting base 11 (pointing to the ground direction in the motor mounting direction).

  In order to efficiently collect the brush wear powder, the guide plate 21 has a different shape and size depending on the position of the guide plate 21. The guide plate 21a on the motor center line is formed in an inverted V shape. The brush wear powder falling from above first slides on the V-shaped part and falls on the left and right guide plates 21b. The guide plate 21b is formed obliquely from the motor center line toward the outer peripheral side, and the brush wear powder that has fallen from the guide plate 21a disposed on the guide plate 21b and the brush wear powder that has fallen directly on the guide plate 21b. Drop them all together. Next to the guide plate 21b, there is a guide plate 21c extending in an arc shape toward the outer peripheral side. A bent portion (return) directed upward in the mounting direction is provided at an end of the guide plate 21c on the lower side in the mounting direction of the motor, so that brush wear powder is reduced from being rolled up from the lower side in the mounting direction of the motor. It is supposed to be.

  Each guide plate 21 is arranged so that the end portion thereof overlaps with the adjacent guide plate 21, and a certain amount of gap is provided along the longitudinal direction of the guide plate 21 at the overlapped portion.

  The brush wear powder that has fallen on the guide plate 21 falls down through the gap and accumulates. The lower side is a space surrounded by a resin material formed by fitting the step 14 of the magnet holder 4 and the brush holder mounting base 11, and this space under the guide plate 21 is where “brush wear powder accumulates”. It will be a “trunk”. Once the brush wear powder that has entered the brush wear powder pool is rolled up by the rotation of the armature (rotor), most of the brush wear powder strikes the guide plate 21 at the upper part and is returned to the lower space. That is, since the end portions of the guide plates 21 are arranged so as to overlap each other in the radial direction, the brush wear powder easily passes from the top to the bottom but is difficult to pass from the bottom to the top.

  The brush wear powder is guided and accumulated in the “brush wear dust pool”, and it is made difficult to scatter from the inside of the motor, so that the brush wear powder can be applied to parts such as shafts and bearings where electrical shorting is a concern. The amount of adhesion can be reduced, and the risk of insulation failure can be reduced.

  As described above, according to the present invention, in a sealed motor in which a large amount of brush wear powder remains in the motor, a space (brush wear dust pool) in which brush wear powder accumulates without greatly changing the component structure around the brush device is provided. It is possible to provide a function of preventing the brush wear powder from scattering inside the motor. As a result, it is possible to reliably prevent insulation failure caused by brush wear powder and provide a highly reliable motor.

  Specifically, a step is provided at one end in the axial direction of an annular member (magnet holder) molded with resin for holding a magnet and extended to a resin mounting base to which the brush holder is fixed. As a result, assembly was made with simple fitting. In addition, the brush holder dust deposits on the stepped portion of the magnet holder prevents the brush wear powder from adhering to the brush lead wires and yokes. A dust-proof wall that prevents the motor (armature) from diffusing into the motor as the motor (armature) rotates is provided on the magnet holder or mounting base.

  That is, one end of the annular resin magnet holder is extended to be wrapped axially with the brush holder portion, and the extended portion is enlarged to the outer peripheral side, and a step portion is provided here. By constructing the stepped extension with the resin mounting base plate for mounting the brush holder by simple fitting, the motor yoke, which is a conductive member, and the brush mounting space can be isolated. As a result, an electrical short circuit that occurs between the brush casings via the brush wear powder can be prevented. Further, the brush wear powder generated by the sliding of the brush is deposited on the step portion of the magnet holder by a guide plate provided on the brush holder and the brush holder mounting base. Further, the wear powder accumulated there is prevented from diffusing into the motor by the armature rotation by the guide plate. In other words, the guide plate has two actions (functions) of dust prevention that induces brush wear powder to be accumulated in one place, and then rises again and is prevented from being accumulated in another place. This can reduce the risk of insulation failure due to the accumulation of brush wear powder.

  In addition, this invention is not limited to an above-described Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described.

DESCRIPTION OF SYMBOLS 1 DC motor 2 Yoke 3 Magnet 4 Magnet holder 5 Output shaft 6 Armature core 7 Armature coil 8 Power supply terminal 9 Brush 10 Brush holder 11 Brush holder mounting base 12 Commutator 13 Front plate 14 Step 15 Magnet insertion hole (groove)
16 Concave portion or convex portion 17 Lead wire for brush 18 Terminal 19 Groove 20 Protrusion or hole 21 Guide plate 21a Guide plate a
21b Guide plate b
21c Guide plate c

Claims (4)

York,
A magnet holder provided on the inner peripheral side of the yoke;
A rotary armature having an armature coil, an armature core, and a commutator;
A brush device for supplying power while slidingly contacting the commutator;
A resin brush holder mounting base for holding the brush device;
A direct current motor comprising:
The magnet holder is fitted with the brush holder mounting base,
The magnet holder has a projecting portion in which an end portion on the side to be fitted with the brush holder mounting base projects radially outward through a step,
The direct current motor in which the protruding portion constitutes a brush wear powder reservoir in which brush wear powder accumulates. The direct current motor according to claim 1,
The magnet holder has an uneven portion that fits with the uneven portion of the brush holder mounting base,
The brush holder mounting base is a direct current motor having a groove that becomes an inlay with the magnet holder. The DC motor according to claim 1 or 2,
A direct current motor in which the yoke has a step corresponding to the step of the magnet holder. A DC motor according to any one of claims 1 to 3,
The direct current motor, wherein the brush holder mounting base includes an induction plate that guides the brush wear powder to the brush wear powder reservoir.

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