US3816783A - Compound spring arrangement for brush holders of rotary electric machines - Google Patents

Compound spring arrangement for brush holders of rotary electric machines Download PDF

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Publication number
US3816783A
US3816783A US00187279A US18727971A US3816783A US 3816783 A US3816783 A US 3816783A US 00187279 A US00187279 A US 00187279A US 18727971 A US18727971 A US 18727971A US 3816783 A US3816783 A US 3816783A
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United States
Prior art keywords
spring
brush
additional
spiral
radial extension
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00187279A
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English (en)
Inventor
T Nakamura
S Kawai
S Motegi
Y Sakuma
H Egawa
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Hitachi Ltd
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Hitachi Ltd
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Publication date
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Publication of US3816783A publication Critical patent/US3816783A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R39/00—Rotary current collectors, distributors or interrupters
    • H01R39/02—Details for dynamo electric machines
    • H01R39/38—Brush holders
    • H01R39/40—Brush holders enabling brush movement within holder during current collection

Definitions

  • the spring arrangement is made by combining two kinds of springs, that is, a conventional spiral spring and a V-shaped leaf spring, in such a manner that the deflection angle of the V-shaped leaf spring opposes the deflection angle of the spiral spring so that the horizontal component of the pressing force of the spiral spring on the brush is cancelled by the horizontal component of the pressing force of the V- shaped leaf spring on the brush for all positions of the brush.
  • This invention relates to brush holders for rotary electric machines which form part of the current collectors, i.e., along with the commutator and collecting ring, of the machine, and more particularly to the spring means for the brush holders thereof.
  • spiral springs are generally employed to press the brush firmly onto the surface of the commutator.
  • This mechanism which produces a pressing of the brush by the spiral springs is quite simple and light in weight.
  • the standard mechanism provides a good association between the commutator and the brush and also has good vibration proof characteristics. As a result, this mechanism is widely employed as a brush holder structure in electric motors for electric locomotives, wherein they usually are subjected to the most severe conditions.
  • FIG. 1 is a prior art brush pressing mechanism of the type described above.
  • Numeral l is a spiral spring made of thin leaf spring material, the inner end of the spiral spring being fixed to a fixed axial member 3.
  • a plate member 2 is attached, through which the stored pressing energy of the spring is exerted on a brush 4.
  • the plate member 2 is rotatable around the fixed axial member 3 and so the direction of the spring pressure exerted through the plate member on one end of the brush is tangential to the rotating route or locus of the plate member. Accordingly, at an early stage in the use of the brushthe tangential force F, is directed to the left, as seen in FIG. 1, with respect to the vertical direction of movement of the brush.
  • the tangential force F therefore comprises a horizontal component Ph so that the vertical component Pv actually urging the brush toward the rotating commutator is smaller than the tangential force P
  • the tangential direction of the pressure of the plate member 2 coincides with the longitudinal axial direction of the brush, that is, the vertical direction, so that the tangential force P itself is the same as that of the vertical force Pv, and all of the stored energy of the spring can be utilized for pressing upon the brushes.
  • FIG. 2 shows the relationship between the deflection angle from a standard point and the tangential force for explaining the pressing force of the spring in FIG. ll.
  • the tangential forces P P and P are proportional to the deflection angles 8 8 and 6 respectively, as shown by the straight line K
  • the vertical force component acting on the brush 4 is Pv, Pv and Pv when the deflection angles are 8 8 and 8 respectively, and the relationship between the deflection angle and the vertical component is represented by the curved line Kv.
  • the vertical force component acting on the brush changes to a large extent in accordance with the height of the brush. Consequently, it is necessary to set the vertical force during the early stage of use high so that it will not become extremely low at the final stage of use of the brush, that is when the limited wearing point of the brush is reached.
  • the vertical force on the brush becomes lower than a certain minimum level, it
  • one object of the present invention is to provide a spiral spring structure for the brush holder of a rotary electric machine which provides improved current collecting and commutating characteristics.
  • Another object of the invention is to provide a spiral spring structure for the brush holder of a rotary electric machine which is particularly suitable for use at high rotational speeds.
  • Another object of the invention is to provide a spiral spring for the brush holder of a rotary electric machine which prolongs the maintenance interval of the brush holder.
  • the present invention provides a second V-shaped leaf spring at the free end of the spiral spring of the brush holder in such a manner that the deflection angle of the V-shaped leaf spring complements that of the spiral spring.
  • the horizontal component of the spiral spring is eliminated; in other words, the pressing force exerted on the brush by the combined spring means consists of only a vertical component.
  • FIG. 1 is a fragmentary side view of a known brush holder construction
  • FIG. 2 is a graph showing the relationship between the deflection angle from a standard point and the tangential force of the spiral spring of FIG. 1;
  • FIG. 3 is a schematic diagram of a combination pressing spring for the brush holder of the present invention.
  • FIG. 4 is a fragmentary side view of the brush holder of the present invention with the brush shown under pressure;
  • FIG. 5 is a graph showing the relationship between the deflection angle from a standard point and the tangential force of the combination spring means of FIG. 3 and FIG. 4;
  • FIG. 6 is a side view of a modified combination spring means of the present invention.
  • FIG. 7 is a side view of another modified combination spring means of the present invention.
  • FIG. 8 is a perspective view of FIG. 7.
  • a spiral spring 10 is formed by coiling a long thin leaf spring.
  • the inner end of the spiral spring 10 is fixed to the fixed axial member 30, and on an outer or free end of the spiral spring 10, a V-shaped leaf spring 50 is attached in such a manner that the deflection angle 8a of the spiral spring 10 opposes the deflection angle 5b of the V-shaped second leaf spring.
  • the V-shaped leaf spring 50 is made of only one sheet-like spring; however, the V-shaped leaf spring can be made by laminating a plurality of sheet-like springs.
  • Numeral is a plate member which transfers the stored energy of the combination spring to the brush 40.
  • the plate member 20 is attached to the free end of the V-shaped leaf spring.
  • Numeral 50a depicts a stopper which extends perpendicularly from the fixed end of the V-shaped leaf spring 50, and the end of the stopper'50a is bent so as to engage an extending portion 50b of the other end portion or free end of the V- shaped leaf spring 50.
  • the combination spring means of the brush holder is constructed as described in connection with FIG. 4.
  • the tangential pressing force of the spiral spring 10 is directed downward to the left, as seen in the drawing, however the tangential pressing force of the V-shaped leaf spring 50 is directed downward to the right so that the horizontal components of the respective tangential forces cancel each other, and the pressing force acting on the brush 40 corresponds only to the vertical component.
  • K10 F o/81o 8a is the deflection angle of the spiral spring 10 during its original stage of use
  • 612 is the deflection angle of the V-shaped leaf spring 50 during its original state of use
  • 8 is a summation of 5a and 8b and represents the deflection angle of the combined spring formed by the spiral spring 10 and the leaf spring 50 in its original position
  • P represents the pressing force of the combined spring on the brush 40 in its original position.
  • the spring constant of the combined spring which is formed by connecting the two springs together, becomes smaller than the spiral spring alone, and the variation of the pressing force on the brush 40 is reduced, as seen by P P and P with respect to the deflection angle 6 8 and 6 respectively, in FIG. 5.
  • the pressing force of the combined spring on the brush decreases. In other words, a favorable pressing force characteristic responsive to the mass of the brush can be obtained. As a result, the wear on the brush caused by mechanical and electrical factors is limited to a minimum.
  • the brush can sit on the commutator firmly and also the association between the brush and the conductor is improved. Consequently, the current collecting and commutating characteristics of the rotary electric machine are improved.
  • the plate member 20 is kept substantially in a horizontal position at all times, the height of the brush can be increased; as the result, the exchanging interval of the brush can be prolonged.
  • the resonance frequency of the combined spring can be controlled by adjusting the frequency of either of the two individual springs.
  • resonance of the combined spring is effectively prevented even for high speed operation of the rotary electric machine in which the resonant frequency of the machine varies over a wide range.
  • edge shape of the brush need not be limited. Any edge shape can be chosen in accordance with the situation.
  • the stopper 50a and the engaging member 50b are arranged on respective end portions of the V-shaped leaf spring to limit the deflection angle thereof within a predetermined amount, the insertion and extraction of the brush 40 from the brush holding frame can be accomplished easily without any trouble and the plate member 20 can be disposed easily and conveniently on a predetermined end portion of the brush.
  • the second spring means can also be a combination of two coil springs 500, as shown in FIGS. 7 and 8, wherein plate member 200 is provided on which each one end portion of the both coil spring is attached.
  • the plate member 200 also serves as an engaging member 50Gb which engages with a stopper 500a extending from each of the other end portions of the coil springs.
  • a spring arrangement for the brush holders of a rotary electric machine comprising a brush disposed for sliding movement in a given direction
  • additional spring means secured to the radial extension of said spiral spring for providing an independent component of force at the radial extension of said spiral spring which is transverse to the path of movement of said brush and equal and opposite to the corresponding transverse force provided by said spiral spring so as to substantially cancel all forces on said brush which are transverse to the path of movement thereof for all positions of said brush, and
  • said additional spring means includes a V- shaped spring having one leg secured to said radial extension of said spiral spring and the other leg secured to said plate member.
  • a spring arrangement as defined in claim 2 wherein said additional spring means further includes stopper means extending from one end of said V- shaped spring for engaging with the other end of said V-shaped spring upon opening of said spring to a predetermined extent to restrict the degree of opening thereof.
  • a spring arrangement for the brush holders of a rotary electric machine comprising a brush disposed for sliding movement in a given direction
  • additional spring means secured to the radial extension of said spiral spring for providing an independent component of force substantially canceling all forces at said radial extension which are transverse to the path of movement of said brush for all positions thereof, and
  • said additional spring means includes an additional spring and stopper means for restricting the length of effective movement of said additional spring.
  • said additional spring means includes a combination spring formed by two coil springs, one end of each coil spring being attached to said radial extension of said spiral spring and the other end of each coil spring being attached to said plate member.
  • said additional spring means further includes stopper means for restricting the degree of opening of said two coil springs.

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  • Motor Or Generator Current Collectors (AREA)
US00187279A 1970-10-07 1971-10-07 Compound spring arrangement for brush holders of rotary electric machines Expired - Lifetime US3816783A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP45087553A JPS5116603B1 (de) 1970-10-07 1970-10-07

Publications (1)

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US3816783A true US3816783A (en) 1974-06-11

Family

ID=13918164

Family Applications (1)

Application Number Title Priority Date Filing Date
US00187279A Expired - Lifetime US3816783A (en) 1970-10-07 1971-10-07 Compound spring arrangement for brush holders of rotary electric machines

Country Status (5)

Country Link
US (1) US3816783A (de)
JP (1) JPS5116603B1 (de)
AU (1) AU431646B2 (de)
DE (1) DE2149909A1 (de)
ES (1) ES202548Y (de)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4625136A (en) * 1983-12-23 1986-11-25 Max Frost Kg Maschinen-Und Apparatebau Brush assembly for electrical machine
US5543675A (en) * 1992-11-25 1996-08-06 Johnson Electric S.A Brush leaf means
US5633550A (en) * 1995-01-23 1997-05-27 Westinghouse Electric Corporation Ground detector brush
US20070001538A1 (en) * 2004-06-03 2007-01-04 Schunk Kohlenstoff-Technik Gmbh Arrangement for holding a carbon brush
DE102005025807B4 (de) * 2004-06-03 2012-03-08 Schunk Kohlenstoff-Technik Gmbh Anordnung zum Halten einer Kohlebürste
US20130187495A1 (en) * 2010-10-13 2013-07-25 Heraeus Materials Technology Gmbh & Co. Kg Contact piece containing precious metal on a spring support having a rotationally symmetrical bending moment
WO2021072523A1 (pt) * 2019-10-18 2021-04-22 Mersen Do Brasil Ltda. Porta escovas para motores elétricos de tração para locomotivas

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5416707U (de) * 1977-07-07 1979-02-02

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1396451A (en) * 1921-04-11 1921-11-08 Lawrence A Merk Brush-holder
US2488788A (en) * 1948-08-30 1949-11-22 Allis Chalmers Mfg Co Brush holder providing resilient application of the brush against the brush holder wall
US2964663A (en) * 1958-02-11 1960-12-13 English Electric Co Ltd Brush holders for dynamo electric machines
US3025422A (en) * 1958-04-24 1962-03-13 Union Carbide Corp Shuntless brush
US3146365A (en) * 1960-11-14 1964-08-25 Gen Motors Corp Electrical machinery brush holder
US3590298A (en) * 1970-03-20 1971-06-29 Reliance Electric Co Brush holder assembly

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1396451A (en) * 1921-04-11 1921-11-08 Lawrence A Merk Brush-holder
US2488788A (en) * 1948-08-30 1949-11-22 Allis Chalmers Mfg Co Brush holder providing resilient application of the brush against the brush holder wall
US2964663A (en) * 1958-02-11 1960-12-13 English Electric Co Ltd Brush holders for dynamo electric machines
US3025422A (en) * 1958-04-24 1962-03-13 Union Carbide Corp Shuntless brush
US3146365A (en) * 1960-11-14 1964-08-25 Gen Motors Corp Electrical machinery brush holder
US3590298A (en) * 1970-03-20 1971-06-29 Reliance Electric Co Brush holder assembly

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4625136A (en) * 1983-12-23 1986-11-25 Max Frost Kg Maschinen-Und Apparatebau Brush assembly for electrical machine
US5543675A (en) * 1992-11-25 1996-08-06 Johnson Electric S.A Brush leaf means
US5633550A (en) * 1995-01-23 1997-05-27 Westinghouse Electric Corporation Ground detector brush
US20070001538A1 (en) * 2004-06-03 2007-01-04 Schunk Kohlenstoff-Technik Gmbh Arrangement for holding a carbon brush
US7265474B2 (en) 2004-06-03 2007-09-04 Schunk Kohlenstoff-Technik Gmbh Spiral and leaf spring arrangement for holding and applying power to a carbon brush
DE102005025807B4 (de) * 2004-06-03 2012-03-08 Schunk Kohlenstoff-Technik Gmbh Anordnung zum Halten einer Kohlebürste
US20130187495A1 (en) * 2010-10-13 2013-07-25 Heraeus Materials Technology Gmbh & Co. Kg Contact piece containing precious metal on a spring support having a rotationally symmetrical bending moment
WO2021072523A1 (pt) * 2019-10-18 2021-04-22 Mersen Do Brasil Ltda. Porta escovas para motores elétricos de tração para locomotivas

Also Published As

Publication number Publication date
ES202548U (es) 1975-11-16
AU3415571A (en) 1973-01-25
ES202548Y (es) 1976-03-01
JPS5116603B1 (de) 1976-05-26
DE2149909A1 (de) 1972-04-13
AU431646B2 (en) 1973-01-25

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