JP2008061471A - Dc motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a DC motor capable of shortening the axial length and preventing generation of faulty current continuity of a portion that is in sliding contact with a brush. <P>SOLUTION: The rotating shaft 11 of a rotor 3, rotatably supported by a pair of bearings 12, 13 installed on a housing 1, is concentrically fixed to a turntable 14 and is provided with a plurality of segments 16 for commutating direct current to the turntable 14. Meanwhile, the housing 1 is fixed to a feed brush 17 in sliding contact with the segments 16. The segments 16 and the feed brush 17 constitute a commutator 4, and a recess 14b, that goes around concentrically with the rotating shaft 11, is formed on the surface side facing the housing 1 of the turntable 14 in the axial direction, and one of the bearings, the bearing 12, is accommodated inside the recess 14b. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a DC motor.

  In a conventional DC motor, for example, the rotary armature type disclosed in Patent Document 1, a pair of bearings, a commutator, and an armature core are arranged in series without axially overlapping the rotation shaft. It becomes the composition. Also in the case of a rotating field type DC motor, the basic arrangement order in the axial direction of the rotating shaft does not change only by arranging magnets instead of the armature core.

JP-A-2005-36650

  In the configuration of Patent Document 1, the required length of the rotating shaft 5 is the sum of at least the axial dimensions of the pair of bearings, commutator, and armature core (magnet in the case of a rotating field type). As a result, there is a problem that the axial dimension of the entire motor is increased.

  Further, since the bearing is disposed immediately above the sliding contact surface between each segment (commutator piece) for current commutation and the power supply brush, the lubricating oil impregnated in the bearing and the sliding between the rotating shaft and the bearing are arranged. There is a problem that the abrasion powder generated by the movement easily reaches the sliding contact portion and current conduction failure is likely to occur between them.

  The present invention has been made to solve the above-described problems, and can reduce the length in the axial direction as compared with the prior art and prevent occurrence of current conduction failure in the sliding contact portion of the brush. The object is to provide a possible DC motor.

  In order to achieve the above object, a DC motor of the present invention is of a rotary armature type, and a rotating shaft of a rotor is rotatably supported by a pair of bearings provided in a housing, and the rotating shaft is concentric with the rotating shaft. The rotating plate is fixed in a shape, and a plurality of segments for commutating a direct current to the armature winding of the rotor are provided along the circumferential direction on the surface of the rotating plate facing the housing in the axial direction. A brush for power supply that is in sliding contact with the segment is fixed to the housing, and a commutator is configured by the segment and the brush for power supply. A recess is formed concentrically with the rotating shaft, and one of the bearings is accommodated in the recess.

  The DC motor according to the present invention is of a rotating field type, and a rotor shaft is rotatably supported by a pair of bearings provided in the housing, and a rotating plate is concentrically fixed to the shaft. The rotating plate is provided with a plurality of segments that commutate DC current in the n-phase along the circumferential direction, and is electrically connected to the segments on the side facing the housing in the axial direction. While n annular slip rings are provided concentrically with the rotating shaft, the housing has a power supply brush that is in sliding contact with the segments, and a DC current after commutation that is in sliding contact with the slip ring. In a DC motor in which power receiving brushes to be supplied to the armature windings are fixed and a commutator is constituted by the segment and the power supply brush, the axial direction of the rotating plate is opposed to the housing On the side, it is formed a recess formed around the said rotary shaft concentrically, is characterized in that one of the bearings of the dual-bearing is accommodated in the recess.

  According to the present invention, since one bearing is housed in the recess formed in the rotating plate, the bearing enters below the sliding contact surface of the power supply or power receiving brush, and the motor is correspondingly increased. The axial length can be shortened. Further, since the exposed end face of the bearing is separated downward from the sliding contact surface of the brush, the lubricating oil impregnated in the bearing and the wear powder generated by sliding between the rotating shaft and the bearing may cause the sliding contact of the brush. Since it becomes difficult to reach the location, it is possible to reliably prevent a current conduction failure from occurring at the location where the brush slides.

Embodiment 1 FIG.
FIG. 1 is a sectional view of a DC motor according to Embodiment 1 of the present invention, and FIG. 2 is an enlarged perspective view showing a portion near a commutator.

  The direct current motor according to the first embodiment is of a so-called rotary armature type, and a stator 2, a rotor 3, and a commutator 4 described later are provided in a housing 1, and the stator 2 is a housing. A plurality of magnets 6 are attached to 1 along the circumferential direction. The rotor 3 is provided in accordance with the number of poles on an iron core 7 arranged with a predetermined space inside the stator 2, and armature windings 8 are wound around each tooth (not shown). In addition, the rotary shaft 11 is inserted into the iron core 7. Then, a rotational force is generated by the interaction between the magnetic flux generated by the armature winding 8 and the magnet 6.

  The rotating shaft 11 is rotatably supported by a pair of bearings 12 and 13 attached to the housing 1, and one end of the rotating shaft 11 protrudes outside the housing 1. In this case, one of the bearings 12 is attached to the inside of a cylindrical inward protruding portion 1 a that protrudes inward on one end side (the upper end side in the drawing) of the housing 1, and the other bearing 13. Is attached to the inside of a cylindrical outward projecting portion 1b formed to project outward on the other end side (lower end side in the figure) of the housing 1. The bearings 12 and 13 are preferably sliding bearings rather than rolling bearings from the viewpoint that the radial dimension can be reduced. Moreover, when the rotating shaft 11 needs to apply an axial load, a bearing capable of applying an axial load such as a deep groove ball bearing is preferable.

  In the housing 1, a rotating plate 14 is fixed concentrically to one end side (the upper end side in the drawing) of the rotating shaft 11. That is, the rotating plate 14 is made of resin, and an insertion hole 14a having the same diameter as the rotation shaft 11 is formed at the center thereof, and the rotation shaft 11 is inserted into the insertion hole 14a. Further, a concave portion 14b that circulates along the insertion hole 14a is formed on the surface of the rotating plate 14 facing the housing 1 in the axial direction. In this case, the diameter of the recess 14b is formed so as to be larger than the outer diameter of the inward protruding portion 1a, and one bearing 12 and a part of the inward protruding portion 1a are formed in the recessed portion 14b. It is stored inside. Further, a plurality of segments (commutator pieces) 16 for commutating a direct current to the armature windings 8 are provided along the circumferential direction at positions outside the concave portions 14b on the surface of the rotating plate 14 facing the housing 1. Are arranged sequentially. Each segment 16 is integrated with the rotating plate 14 by, for example, insert molding, and is electrically connected to the armature winding 8.

  On the other hand, two power supply brushes 17 that are urged by a compression spring 18 and slidably contact the segment 16 are provided at a position facing the rotating plate 14 on one end side of the housing 1. The commutator 4 is constituted by the brush 17.

  Thereby, when the rotating plate 14 is rotated integrally with the rotor 3, the direct current fed from the power supply brush 17 is commutated by each segment 16 and flows to the armature winding 8 of the rotor 3. Thus, a magnetic flux corresponding to the rotation angle is generated in each tooth of the iron core 7.

  In the DC motor according to the first embodiment having the above-described configuration, one of the bearings 12 enters below the surface where the power supply brush 17 is in sliding contact with the segment 16 by the recess 14b provided in the rotating plate 14. Accordingly, the axial length of the entire motor can be shortened.

  Moreover, for example, as shown in FIG. 1, when the DC motor is installed in a state where the rotary shaft 11 is in the vertical direction, it is generated by the lubricating oil impregnated in the bearing 12 or sliding between the rotary shaft 11 and the bearing 12. Even if the worn powder that has flowed out flows into the recesses 14b, they accumulate in the recesses 14b and are unlikely to reach the locations where the power supply brush 17 is in sliding contact with the segments 16. For this reason, it is possible to reliably prevent a current conduction failure from occurring at the sliding contact portion of the power supply brush 17 with the segment 16.

  In the first embodiment, the diameter of the recess 14b of the rotating plate 14 is formed so as to have the same diameter from the bottom side along the axial direction toward the opening side, but as shown in FIG. An inner flange portion 14c projecting radially inward can be formed on the opening end side of the recess 14b.

  According to such a configuration, for example, even when a DC motor is installed so that the rotating shaft 11 is substantially horizontal, it is generated by the lubricating oil impregnated in the bearing 12 or sliding between the rotating shaft 11 and the bearing. The worn powder is blocked by the inner flange portion 14c and hardly flows out of the recess 14b to the outside, so that it is more difficult to reach the portion where the power supply brush 17 is in sliding contact with the segment 16. For this reason, it is possible to more reliably prevent a current conduction failure from occurring at the sliding contact portion of the power supply brush 17 with the segment 16.

  In the first embodiment, the rotary shaft 11 is inserted into the insertion hole 14 a formed in the center of the rotating plate 14, and one end portion of the inserted rotary shaft 11 is supported by one bearing 12. For example, as shown in FIG. 4, a resin-made rotating plate 14 is integrally attached to one end of the rotating shaft 11, and a cylindrical convex portion that protrudes upward concentrically with the rotating shaft 11 at the center of the rotating plate 14. 14 d is formed, and a concave portion 14 b that goes around the convex portion 14 d is formed outside the convex portion 14 d, and the convex portion 14 d is rotatably supported by a bearing, and the bearing 12 and the inward projecting portion 1 a are disposed in the concave portion 14 b. It can also be set as the structure which accommodated.

  Alternatively, instead of integrally forming the convex portion 14d of the rotating plate 14 with resin, as shown in FIG. 5, a metal support shaft member 19 with a flange is integrally provided on the rotating plate 14 by insert molding. It is also possible to adopt a configuration in which a cylindrical convex portion 19 a that protrudes upward concentrically with the rotary shaft 11 at the center of the shaft member 19 is rotatably supported by the bearing 12.

  If the configuration shown in FIG. 4 or FIG. 5 is adopted, it is convenient because the convex portions 14d and 19a can be selected and used so as to be a material having good compatibility with the bearing 12 in terms of sliding performance.

Embodiment 2. FIG.
FIG. 6 is a cross-sectional view of a DC motor according to Embodiment 2 of the present invention, and FIG. 7 is an enlarged perspective view showing a portion near the commutator, which corresponds to Embodiment 1 shown in FIGS. 1 and 2. The same reference numerals are given to the components.

  The DC motor according to the second embodiment is of a so-called rotating field type, and is provided with a stator 2, a rotor 3, and a commutator 4 to be described later in a housing 1. The armature winding 8 is wound around the teeth of the iron core 7 fixed to 1. Further, the rotor 3 has a field magnet 6 attached to a cylindrical body 9 arranged concentrically with a predetermined space inside the stator 2, and a rotating shaft 11 is attached to the cylindrical body 9. Is inserted and configured. Then, a rotational force is generated by the interaction between the magnetic flux generated by the armature winding 8 and the magnet 6. Thus, when the iron core 7 and the armature winding 8 are provided on the stator 2 side, since the weight on the rotor 3 side is reduced, there is an advantage that inertia is reduced and eccentricity is hardly generated.

  The rotating shaft 11 is rotatably supported by a pair of bearings 12 and 13 attached to the housing 1, and one end of the rotating shaft 11 protrudes outside the housing 1. In this case, one of the bearings 12 is attached to the inside of a cylindrical inward protruding portion 1a that protrudes inward on one end side (upper side in the figure) of the housing 1, and the other bearing 13 is At the other end side (lower end side in the figure) of the housing 1, the housing 1 is attached to the inside of a cylindrical outward projecting portion 1 b that projects outward.

  In the housing 1, a rotating plate 14 is fixed concentrically to one end side (the upper end side in the drawing) of the rotating shaft 11. That is, the rotating plate 14 is made of resin, and an insertion hole 14a having the same diameter as the rotation shaft 11 is formed at the center thereof, and the rotation shaft 11 is inserted into the insertion hole 14a. Further, a concave portion 14b that circulates along the insertion hole 14a is formed on the surface of the rotating plate 14 facing the housing 1 in the axial direction. In this case, the diameter of the recess 14b is formed to be larger than the outer diameter of the inward protruding portion 1a, and one bearing 12 and a part of the inward protruding portion 1a enter into the recessed portion 14b for storage. Has been.

  Further, n (three in this example) annular slip rings 21 are provided concentrically with the rotary shaft 11 at positions outside the recess 14b on the surface of the rotary plate 14 facing the housing 1. Yes. Furthermore, a plurality of segments 16 (four pieces of commutators) for commutating a DC current to each armature winding 8 are sequentially arranged on the outer peripheral surface of the rotating plate 14 along the circumferential direction. The segments 16 and the slip rings 21 are integrated with the rotating plate 14 by, for example, insert molding, and each segment 16 has an n-phase (three phases in this example) inside the rotating plate 14. Are electrically connected individually.

  On the other hand, at a position facing the rotating plate 14 on one end side (upper end side in the figure) of the housing 1, three power receiving brushes 22 that are urged by the compression springs 23 and individually slidably contact the slip ring 21 are provided. In addition, two power supply brushes 17 that are urged by a compression spring 18 and slidably contact each segment 16 are provided at positions opposed to the housing 1 in the radial direction of the rotating plate 14. The segment 16 and the power supply brush 17 constitute the commutator 4. Each power receiving brush 22 is electrically connected to the armature winding 8 of the stator 2.

  As a result, when the rotating plate 14 is rotated integrally with the rotor 3, the DC current fed from the feeding brush 17 is commutated by each segment 16, and the commutated three-phase current is converted to each slip ring. By flowing through the armature winding 8 of the stator 2 via the power receiving brush 21 and the power receiving brush 22, a magnetic flux corresponding to the rotation angle is generated in each tooth of the iron core 7.

  In the DC motor according to the second embodiment having the above-described configuration, the bearing 12 has a recess 14b provided in the rotating plate 14 than the surface where the power receiving brush 22 is in sliding contact with the slip ring 21 due to the recess 14b. Since it has entered the lower side, the axial length of the entire motor can be reduced by that amount, and the lubricating oil impregnated in the bearing 12 and wear caused by sliding between the rotating shaft 11 and the bearing 12 can be reduced. Even if the powder flows out, they accumulate in the recesses 14b and do not reach the place where the power receiving brush 22 is in sliding contact with the slip ring 21. It can be surely prevented.

  Further, in the case of the second embodiment, since each segment 16 is provided along the circumferential direction of the outer peripheral surface of the rotating plate 14, the outer diameter of the rotating plate 14 is reduced even when the recess 14 b is provided in the rotating plate 14. The increase can be suppressed.

  That is, in the conventional DC motor of this type, the segments 16 are arranged concentrically outside the slip ring 21 on the same plane as the slip ring 21 forming surface. As a result, the diameter of the rotating plate 14 is also increased. As a result, the sliding speed when the power supply brush 17 is in sliding contact with the segment 16 is increased, and wear of both the members 16 and 17 is increased. On the other hand, in the present invention, since the segment 16 is provided on the outer peripheral surface of the rotating plate 14 and the power supply brush 17 is in sliding contact with the segment 16, even when the concave portion 14b is formed on the rotating plate 14, the slip is detected. Only the formation surface of the ring 21 needs to be secured, and there is no need to increase the outer diameter of the rotating plate 14 any more. For this reason, the outer diameter of the rotating plate 14 can be reduced, and an increase in the sliding speed when the power supply brush 17 is in sliding contact with the segment 16 can be suppressed. As a result, the wear of both 16 and 17 can be reduced, and the life can be extended.

  It should be noted that the configuration of FIGS. 3 to 5 shown as a modification of the first embodiment can be applied to the second embodiment as well.

It is sectional drawing of the DC motor in Embodiment 1 of this invention. It is a perspective view which expands and shows the part of the commutator vicinity in the DC motor. It is sectional drawing which shows the principal part of the modification of Embodiment 1 of this invention. It is sectional drawing which shows the principal part of the other modification of Embodiment 1 of this invention. It is sectional drawing which shows the principal part of the further another modification of Embodiment 1 of this invention. It is sectional drawing of the DC motor in Embodiment 2 of this invention. It is a perspective view which expands and shows the part of the commutator vicinity in the DC motor.

Explanation of symbols

1 housing, 2 stator, 3 rotor, 4 commutator, 8 armature winding,
11 Rotating shaft, 12, 13 Bearing, 14 Rotating plate, 14b Recessed part,
16 segments (commutator pieces), 17 power supply brushes, 21 slip rings,
22 Power receiving brush.

Claims (4)

A rotary armature type, wherein a rotary shaft of a rotor is rotatably supported by a pair of bearings provided in a housing, and a rotary plate is concentrically fixed to the rotary shaft. A plurality of segments for commutating direct current in the armature winding of the rotor are provided along the circumferential direction on the side facing the housing in the direction, and a power supply brush that is in sliding contact with the segments is fixed to the housing. In the DC motor in which a commutator is constituted by the segment and the power supply brush, a concave portion that concentrically rotates with the rotating shaft is provided on the surface facing the housing in the axial direction of the rotating plate. A direct current motor formed, wherein one of the two bearings is accommodated in the recess. The rotating shaft of the rotor is rotatably supported by a pair of bearings provided in the housing, and a rotating plate is concentrically fixed to the rotating shaft. A plurality of segments for commutating DC current in the n-phase are provided along the circumferential direction, and n annular slips electrically connected to the segments are provided on the side facing the axial housing. A ring is provided concentrically with the rotating shaft, while the housing is provided with a power supply brush that is in sliding contact with each segment, and a DC current after commutation is supplied to the stator armature winding by sliding contact with the slip ring. In the direct current motor in which the power receiving brush is fixed and the commutator is configured by the segment and the power supply brush, the rotating shaft is disposed on the surface facing the housing in the axial direction of the rotating plate. DC motor recess orbiting heart shape is formed, one of the bearings of the two bearing within this recess, characterized in that it is housed. The DC motor according to claim 2, wherein each of the segments is provided on an outer peripheral surface of the rotating plate. The DC motor according to any one of claims 1 to 3, wherein an inner flange portion projecting radially inward is formed on an opening end side of the concave portion.

Images