JP2014068533A - Brush device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small size high-speed commutator motor using a torsion brush spring and a resin bound carbon brush capable of increasing the reliability of the carbon brush upon an occurrence of overload.SOLUTION: A torsion brush spring 23 includes: a cylindrical coil 23a having plural windings; a brush spring load bearing part 23b extending from one end of the coil 23a; and a pressure-contact part 23c extending from the other end of the coil 23a to pressurize the carbon brush 21. The pressure-contact part 23c for pressurizing the carbon brush 21 has a coil-like shape having plural contact points.

Description

  The present invention relates to a brush device used for a commutator motor mainly using a commutator and a carbon brush used for a blower such as a small household vacuum cleaner.

  In recent years, household vacuum cleaners have come to be favored by easy-to-use products, and the commutator motors mounted on them have been demanded for high-speed, high-efficiency commutator motors that are small and lightweight. It has been.

  Therefore, the conventional commutator motor generally has a configuration in which the carbon brush is pressed by a compression coil spring in which elastic wires are laminated in a coil shape. Therefore, a space for housing the coil spring is required, and as a result, the carbon brush is accommodated. There has been a problem that the brush cage assembly becomes longer in the radial direction (see, for example, Patent Document 1).

  In order to overcome the problem, a brush device using a torsion coil spring that does not require a compression coil storage space has been invented. However, since the contact point with the carbon brush is a point contact, the vibration of the carbon brush is likely to occur. An invention has been invented in which the rear end portion of the brush is inclined and the torsion brush spring contact portion is bent to form a line contact, or a brush device having a plurality of contact points by a leaf spring (see, for example, Patent Document 2). ).

JP 08-214507 A Japanese Patent Laid-Open No. 11-187625

  However, in the former conventional technique, it is necessary to form the rear end of the brush in an inclined (tapered) shape, which not only increases the cost of the carbon brush, but also has a linear contact portion that contacts the carbon brush. It has the subject that it will incline and the load variation of pressurization will generate | occur | produce.

  In the latter prior art, the use of a plate material for the brush spring increases the contact area with the carbon brush, ensuring stable pressurization, while the operating range for pressurizing the carbon brush is narrow and unreasonable operation. When used in a range, there is a problem that deformation and breakage are likely to occur, and cost is increased.

  Furthermore, when employed in a commutator motor having a high speed rotation of 30000 r / min or more, a resin-bonded system with a relatively soft hardness is used to improve the decrease in seating property due to vibration of the carbon brush during high speed rotation. Although brush devices using carbon brushes have been studied in the past, the carbon brush material is a resin-bonded carbon brush, so the hardness of the carbon brush is reduced when overloaded, and the carbon brush itself breaks due to the applied pressure. I had the problem of end up.

In order to solve the above problems, the torsion brush spring in the brush device of the present invention includes a cylindrical coil portion having a plurality of turns, a brush spring load support receiving portion extending from one end of the coil portion, and the other end of the coil portion. A torsion coil spring having a pressure contact portion that extends and pressurizes the carbon brush, and the action contact portion that pressurizes the carbon brush has a coil shape having a plurality of contact portions.

  According to the brush device of the present invention, the pressure load of the brush spring can be divided and dispersed by a coil shape in which a plurality of windings are wound, so that localized concentration of the pressure load can be prevented, and a decrease in strength occurs during overload. In the resin-bonded carbon brush, the brush breaking phenomenon can be prevented, and a stable and reliable brush device can be obtained.

The partial cross section figure of the commutator motor provided with the brush apparatus in embodiment of this invention The external view and detail drawing which show the shape of the brush apparatus in embodiment of this invention FIG. 3 is an external view of a torsion brush spring of the brush device according to the embodiment of the present invention.

  FIG. 1 is a partial cross-sectional side view of a commutator motor 10 provided with a brush device according to an embodiment of the present invention. FIGS. 2 and 3 are external views showing the brush device according to an embodiment of the present invention. It is.

  The commutator motor 10 is provided with two brackets, a steel plate bracket B12 having a shape substantially on a cup opened on one side, and a synthetic resin bracket A11 disposed in an opening of the bracket B12. A11 is fastened and fixed to the bracket B12 by a plurality of fixing screws.

  The bracket B has a field magnet 13 held and fixed therein, an electric machine having a commutator 16 disposed so as to penetrate the center of the field magnet 13 and rotatably held and fixed by a pair of bearings 15. It has a child 14. The pair of bearings 15 are held by brackets A11 and B12, respectively.

  The bracket A11 includes a pair of deformed tube holders 20 that hold a deformed tube 22 formed in a substantially rectangular shape from a steel plate containing a resin-bonded carbon brush 21, and a pressure for pressing the carbon brush 21 to the commutator 16. The brush device 30 includes a torsion brush spring 23.

  The torsion brush spring 23 includes a cylindrical coil portion 23a that has a plurality of turns and generates a brush spring load when twisted, a brush spring load support receiving portion 23b that extends from one end of the coil portion 23a and supports the brush spring load, and a coil The pressure contact portion 23c extends from the other end of the portion 23a and has a coil shape having a plurality of contact portions for pressing the carbon brush 21.

  The coil portion 23a is inserted and supported in a freely rotatable state on a support 11a provided on the bracket A11. The brush spring load support receiving portion 23b is held and fixed by the stopper portion 11b, and at the same time the pressure contact portion 23c is indicated by the arrow in FIG. After rotating to a predetermined angle and generating an appropriate brush spring load, as shown in Fig. 5, the rear end surface of the carbon brush 21 is pressed and pressed by a press contact portion 23c having a plurality of coil shapes.

  With the above configuration, the contact portion of the torsion brush spring that comes into contact with the carbon brush is dispersed into a plurality of coil shapes with a plurality of turns, and the load concentrated locally can be reduced.

  By reducing the brush spring load, even if the resin-bonded carbon brush loses its hardness during overload, it can prevent the carbon brush from rupturing due to stress (load) concentration, so resin-bonded carbon under high-speed rotation The seating and following ability of the brush can be secured.

  Further, since it is not necessary to process the rear end portion of the carbon brush into an inclined shape, a low-cost brush device can be obtained.

  Therefore, it is possible to obtain a highly reliable commutator motor that is small and inexpensive.

  The brush device of the present invention can improve the reliability of a carbon brush at the time of overload in a high-speed rotating commutator motor using a torsion brush spring and a resin-bonded carbon brush, and aims to reduce the size of the commutator motor. It is useful for the use.

DESCRIPTION OF SYMBOLS 10 Commutator motor 21 Carbon brush 23 Torsion brush spring 23a Coil part 23b Brush spring load support receiving part 23c Pressure contact part 30 Brush apparatus

Claims (2)

A cylindrical coil portion having a plurality of turns;
A brush spring load support receiving portion extending from one end of the coil portion;
A brush device provided with a torsion brush spring having a coil-like pressure contact portion that extends from the other end of the coil portion and presses the carbon brush with a plurality of contact portions. The brush device according to claim 1, wherein the carbon brush is a resin-bonded carbon brush.

Images