JP6344413B2 - Commutator motor - Google Patents

Description

  The present invention relates to a commutator motor that is used in an electric device such as a vacuum cleaner, and includes a commutator and a brush.

  Generally, in a commutator motor, a configuration is adopted in which a brush attached to the casing side and a commutator attached to the rotor side are brought into contact with each other in order to supply current to the rotating body (rotor) from the outside. Yes. Here, in order for the electric motor to operate stably, it is required to maintain a state where the brush is pressed against the commutator with an appropriate load (pressing force). When this pressing force is insufficient, the contact state between the brush and the commutator becomes unstable when the rotor rotates, and the wear of the brush is likely to proceed due to the occurrence of sparks. On the other hand, when the pressing force is excessive, the brush not only wears but also the rotational efficiency of the rotor decreases. Therefore, it is ideal that the pressing force of the brush is maintained at an appropriate value (specified value at the time of design) until the life of the electric motor.

  However, the brush is often pressed against the commutator using a linear spring such as a compression coil spring or a torsion coil spring. In this configuration, when the amount of bending of the spring decreases due to wear of the brush, the pressing force decreases in proportion to the decrease in the amount of bending. In order to solve this problem, the prior art described in Patent Document 1 realizes a nonlinear characteristic for generating an appropriate pressing force by distorting the shape of a linear spring (compression coil spring). ing.

JP 2004-120890 A

  However, in the above-described prior art, the strain shape of the linear spring is likely to vary depending on the assembly state of the linear spring, material variations, usage state of the electric motor, and the like. For this reason, in the prior art, there is a problem that it is not always possible to reproduce a certain distortion shape, and it is difficult to obtain a desired nonlinear characteristic.

  The present invention has been made to solve the above-described problems. Even when the shape of the spring fluctuates, the state in which an appropriate pressing force is applied to the brush is stably obtained by utilizing the non-linear characteristic of the spring. An object of the present invention is to provide a commutator motor that can be held at a distance.

The commutator motor according to the present invention includes a frame, a stator fixed to the inner peripheral side of the frame, a rotating shaft rotatably supported in the frame, and a radial direction of the stator and the rotating shaft. in opposite to the rotor, a commutator fixed to the rotary shaft, fixed to the frame, possess protrude in the radial direction of the rotary shaft toward the tip commutator, a notch on one side of the distal tip portion A brush holder that has no notch on the other side , a brush that is held by the brush holder so as to be displaceable in the radial direction of the rotating shaft, and a load that contacts the commutator, and a load-deflection that represents the relationship between the spring load and the amount of deflection A non-linear softening spring that is formed by a spring whose amount characteristic is a non-linear characteristic, and that pushes the brush toward the commutator by pulling the brush from the notch on one side of the brush holder at the tip of the spring attached to the brush; It is equipped with.

  According to the present invention, even if the amount of deflection of the nonlinear softening spring changes due to various factors, the pressing force applied to the brush can be stably maintained in an appropriate range by utilizing the nonlinear characteristics. As a result, it is possible to achieve the desired pressing force from the beginning of use of the electric motor to the end of its life, to suppress the wear of the brush and the like, and it is possible to extend the life of the electric motor.

It is sectional drawing which shows the commutator motor by Embodiment 1 of this invention. It is sectional drawing which expands and shows the brush mechanism etc. in FIG. It is a characteristic diagram which shows the load-deflection amount characteristic of a nonlinear softening spring and a linear spring. It is sectional drawing which expands and shows the brush mechanism etc. of the commutator motor by Embodiment 2 of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. In each drawing, common elements are denoted by the same reference numerals, and redundant description is omitted. Further, the present invention is not limited to the following embodiments, and can be variously modified without departing from the gist of the present invention. Further, the present invention includes all combinations of configurations that can be combined among the configurations shown in the following embodiments.

Embodiment 1 FIG.
FIG. 1 is a cross-sectional view showing a commutator motor according to Embodiment 1 of the present invention. In this figure, the commutator motor mounted on the electric blower is illustrated. The commutator motor includes a casing 1, a stator 2, a rotating shaft 3, a rotor 6, a commutator 8, a brush mechanism 10, and the like. The casing 1 constitutes an outer shell and a frame of the commutator motor, and is formed in a stepped cylindrical shape. An air inlet 1 </ b> A is opened on one end side of the casing 1, and an air outlet (not shown) is opened on the other end side of the casing 1. A plurality of stators 2 are fixed side by side in the circumferential direction on the inner peripheral side of the casing 1.

  The rotating shaft 3 is disposed on the central axis within the casing 1 and extends in the axial direction. Both end sides of the rotating shaft 3 are rotatably supported by bearings 4 respectively. The bearing 4 on one end side is attached to a disk-shaped fixed guide vane 5 fixed in the casing 1. Further, the bearing 4 on the other end side is fitted in a recess in the casing 1. A rotor 6 is fixed to the outer peripheral side of the rotating shaft 3. The rotor 6 faces each stator 2 in the radial direction of the rotating shaft 3. A disk-shaped fan 7 is fixed to one end side of the rotating shaft 3. The fan 7 faces the fixed guide blade 5 in the axial direction of the rotating shaft 3.

  An annular commutator 8 formed of a conductive material such as metal is fixed to the outer peripheral side of the rotating shaft 3. The brush 12 of the brush mechanism 10 described later is in contact with the outer peripheral surface of the commutator 8 at a plurality of locations in the circumferential direction. The brush mechanism 10 is a mechanism for energizing the rotating rotor 6 via the brush 12 and the commutator 8 that are in contact with each other.

  When the commutator motor configured as described above is operated, when a current is applied from the outside, a magnetic rotational force is generated between the stator 2 and the rotor 6 so that the rotating shaft 3 rotates. Thereby, when the fan 7 rotates with the rotating shaft 3, air is sucked from the suction port 1 </ b> A of the casing 1. This air is guided by the fan 7 and the fixed guide vane 5 and is blown out from the outlet of the casing 1 to the outside.

  Next, with reference to FIG. 2, the several brush mechanism 10 arrange | positioned so that the commutator 8 may be enclosed in the casing 1 is demonstrated. In addition, since each brush mechanism 10 has the same structure, in the following description, one brush mechanism 10 will be described as an example. FIG. 2 is an enlarged cross-sectional view of the brush mechanism and the like in FIG. As shown in FIG. 2, the brush mechanism 10 includes a brush holder 11, a brush 12, and a mainspring spring 13.

  The brush holder 11 is formed of a material such as metal or resin, for example, and has a bottomed cylindrical shape with an open end. The bottom of the brush holder 11 is fixed to the inner peripheral side of the casing 1. The tip of the brush holder 11 protrudes in the radial direction of the rotary shaft 3 toward the commutator 8. The brush holder 11 is configured to allow the brush 12 to be displaced with respect to the radial direction of the rotary shaft 3 while holding the brush 12 in a constant posture with the tip portion facing the commutator 8.

  The brush 12 is the same as a conventional brush, and is formed in a cylindrical shape using a conductive material such as metal. The brush 12 is configured to approach and separate from the commutator 8 while being held by the brush holder 11. The tip of the brush 12 is pressed against the outer peripheral surface of the commutator 8 by the spring force of the mainspring spring 13 and is held in contact with the commutator 8.

  The mainspring spring 13 is formed, for example, by winding a steel plate having spring properties in a spiral shape. A main body portion wound in a spiral shape in the mainspring spring 13 is attached to the casing 1 side, for example. Further, the front end portion of the mainspring spring 13 is attached to the bottom side of the brush 12. As a result, the mainspring spring 13 supports the brush 12 and presses the brush 12 against the commutator 8 by a spring force in a direction in which the tip of the mainspring spring 13 is rewound onto the spiral main body portion. The pressing force (spring load) when the mainspring spring 13 presses the brush 12 against the commutator 8 is maintained in an appropriate range as described later.

  The mainspring spring 13 is constituted by a spring in which the load-deflection amount characteristic representing the relationship between the spring load and the amount of deflection becomes a nonlinear characteristic, that is, a nonlinear softening spring. FIG. 3 is a characteristic diagram showing load-deflection characteristics of the nonlinear softening spring and the linear spring. As shown by a dotted line in this figure, a general linear spring such as a coil spring or the like increases the amount of deflection in proportion to the load as the spring load increases. Therefore, the load-deflection amount characteristic is linear. It becomes a characteristic. On the other hand, the non-linear softening spring such as the mainspring spring 13 has non-linear characteristics as indicated by a solid line in FIG. In this nonlinear characteristic, the amount of deflection increases with the load of the spring, but when the load increases to some extent, the amount of increase in the amount of deflection decreases.

  In the present embodiment, the spring 12 is used in the load stabilization region (a) in FIG. 3 after the brush 12 is pressed against the commutator 8 by the mainspring 13 by utilizing this non-linear characteristic. That is, the amount of deflection of the mainspring spring 13 when the brush 12 is pressed against the commutator 8 is set to be, for example, the value A within the load stabilization region (a). Here, the load stable region (a) is defined as a region in which the change of the load with respect to the change of the deflection amount falls within the allowable range on the characteristic line of the load-deflection amount characteristic of the mainspring spring 13. The allowable load range is a load range appropriate as a pressing force applied to the brush 12, and is determined in advance at the time of design, for example.

  According to the above configuration, even if the amount of deflection of the mainspring spring 13 changes due to, for example, the assembly state of the spring, material variations, use state of the electric motor, etc., the load of the mainspring spring 13 is within the load stable region (a). Can be kept within a certain range. In other words, by utilizing the non-linear characteristic of the mainspring spring 13, fluctuations in the pressing force applied by the mainspring spring 13 to the brush 12 can be suppressed, and the pressing force can be stably held in an appropriate range. As a result, the desired pressing force can be realized from the start of use of the electric motor to the end of its life, and wear of the brush 12 can be suppressed. Further, the energized state of the brush mechanism 10 can be stabilized. Therefore, it is possible to extend the life of the electric motor while using the low cost spring spring 13.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference to FIG. The feature of this embodiment is that an air spring is used as the nonlinear softening spring. FIG. 4 is an enlarged sectional view showing a brush mechanism and the like of the commutator motor according to the second embodiment of the present invention. As shown in this figure, the commutator motor of this embodiment includes a brush mechanism 20. The brush mechanism 20 includes a brush holder 21 and a brush 22 as in the first embodiment, but further includes an air spring 23 as a non-linear softening spring.

  The air spring 23 is a spring that uses the elasticity of the air enclosed in the sealed space, and the load-deflection amount characteristic of the air spring 23 is set to a non-linear characteristic (FIG. 3) similar to that of the mainspring spring 13. Yes. And in this Embodiment, the air spring 23 is used in the load stable area | region (a) in FIG. In the present embodiment configured as described above, the same effect as in the first embodiment can be obtained.

  In the first and second embodiments, the case where the commutator motor is mounted on the electric blower is illustrated. However, the present invention is not limited to this, and is also applicable to a single commutator motor and a commutator motor mounted on various devices other than the electric blower.

1 Casing (frame)
2 Stator 3 Rotating shaft 4 Bearing 5 Fixed guide vane 6 Rotor 7 Fan 8 Commutators 10 and 20 Brush mechanisms 11 and 21 Brush holders 12 and 22 Brush 13 Mainspring spring (non-linear softening spring)
23 Air spring (non-linear softening spring)

Claims (3)

Frame,
A stator fixed to the inner peripheral side of the frame;
A rotating shaft rotatably supported in the frame;
A rotor fixed to the rotating shaft and facing the stator in the radial direction of the rotating shaft;
A commutator fixed to the rotating shaft;
Fixed to said frame, projecting in the radial direction of the rotating shaft tip toward the commutator, brush holder no-out the other side cutouts have a notch on one side of the front end portion and the distal portion When,
A brush that is held by the brush holder so as to be displaceable in the radial direction of the rotary shaft,
The load-deflection amount characteristic representing the relationship between the spring load and the amount of deflection is formed by a spring having a nonlinear characteristic, and the brush is cut at one end of the brush holder at the tip of the spring attached to the brush. A non-linear softening spring that presses against the commutator by pulling in the direction of the commutator from a notch,
Commutator motor equipped with.   The commutator motor according to claim 1, wherein the nonlinear softening spring is a mainspring spring.   The amount of deflection of the non-linear softening spring in a state where the brush is pressed against the commutator is a value within a region where the change in the load with respect to the change in the amount of deflection falls within an allowable range on the characteristic line of the load-deflection amount characteristic. The commutator motor according to claim 1 or 2, wherein the commutator motor is set.

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