Classifications

• • 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
  • H01R39/383—Brush holders characterised by the electrical connection to the brush holder
• • 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
  • H01R39/381—Brush holders characterised by the application of pressure to brush
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K5/00—Casings; Enclosures; Supports
  • H02K5/04—Casings or enclosures characterised by the shape, form or construction thereof
  • H02K5/14—Means for supporting or protecting brushes or brush holders
  • H02K5/143—Means for supporting or protecting brushes or brush holders for cooperation with commutators
  • H02K5/148—Slidably supported brushes

Definitions

• the present invention relates to a brush holder assembly for an electric motor.
• the present invention relates to a brush holder assembly
• a brush holder assembly comprising an annular mounting plate positioned on the same axis as a commutator of an electric motor; a plurality of tubular brush holders mounted radially on the mounting plate are distributed around the commutator, each being approximately as long as the mounting plate is wide.
• each brush holder is made from a substantially flat metal sheet obtained by blanking, has a substantially square shaped cross section and has two side faces that are substantially parallel to each other and to the mounting plate, and another two side faces that are substantially parallel to each other and perpendicular to the mounting plate, the side faces being substantially rectangular in shape.
• Each brush holder is slidably engaged by a brush which is held in contact with the commutator by a spring and which is equipped with an electric connecting cable that normally extends from one end of it and is folded around the brush holder and hooked to the mounting plate.
• a brush holder with a constant force spring is described in document DE-30 10 036 Al .
• One aim of the present invention is to provide an improved brush holder assembly that enables the brushes to wipe the commutator without causing excessive friction and without the risk of damaging the electrical connecting cable.
• Another aim of the invention is to provide a brush holder assembly in which the brushes wear at a regular rate.
• the present invention provides an electric motor brush holder assembly as defined in claim 1.
• Figure 1 is a schematic front view of a preferred embodiment of the brush holder assembly according to the invention.
• Figure 2 is a schematic perspective view of a detail from Figure 1;
• Figure 3 is a side view of the detail of Figure 2; and
• FIG 4 is a schematic perspective view of another embodiment of the detail from Figure 1.
• the numeral 1 denotes in its entirety a brush holder assembly for an electric motor (not illustrated) comprising an annular mounting plate 2 which, in this instance, is substantially flat and extends coaxially with a longitudinal axis 3 of a rotating commutator 4 of the electric motor (not illustrated) .
• the mounting plate 2 may differ from the substantially flat shape illustrated in Figure 1.
• the unit 1 also comprises a plurality of tubular brush holders 5 (in this instance, four holders 5), mounted on the plate
• each holder 5 is made from a substantially flat metal sheet (not illustrated) which is slightly shorter in length, measured in a direction parallel to the direction 6, than the width of the mounting plate 2, also measured in a direction parallel to the direction 6.
• Each holder 5 has a substantially square shaped cross section and has two side faces 7 that are substantially parallel to each other and to the mounting plate 2, and two side faces 8 that are substantially parallel to each other and perpendicular to the faces 7.
• Each holder 5 is slidably engaged by a contact brush 9 a first end 10 of which, under the action of a flat spring 11, is normally in contact with the commutator 4.
• the spring 11 has a central portion 12 which extends between the holder 5 and the brush 9 and which is designed to engage a second end 13 of the brush 9, opposite the first end 10, and two rolled up end portions 14, each of which engages a tab 15 protruding outwards from the holder 5.
• the tab 15 accommodates the end portion 14 of the spring 11 and is shaped in such a way as to allow the portion 14 to turn with the minimum of friction.
• the tab 15 comprises a first portion 15a that is substantially perpendicular to the direction 6, and a second portion 15b that is inclined by an angle such that one end of it allows the spring portion 14 to be stably accommodated and the other end allows it to turn freely with the minimum of friction.
• the holder 5 For guiding the central portion 12 of the spring 11 and allowing it to slide easily, the holder 5 also comprises a groove 8a on each of the side faces 8.
• the portions 14 roll themselves up in such a way that the spring 11 applies a constant force on the brush 9, causing the brush 9 to move along the holder 5 in the direction 6.
• the brush 9 also has an electric connecting cable 16 that protrudes from the end 13, is folded over the mounting plate 2, and, during the movement of the brush 9 along the holder 5 towards the commutator 4, slidably engages an undercut 17, which is made in one of the faces 8, extends in the direction 6 and which is substantially V-shaped with a rounded stop end 18 whose radius of curvature is substantially the same as the radius of the cable 16.
• the undercut 17 enables the cable 16 to move freely in the direction 6 along the holder 5 as the brush 9 is used up, thus preventing the cable 16 from being damaged by the holder 5.
• Figure 4 illustrates an alternative embodiment of the holder 5.
• the holder 5 has a slot 7a made in its top face 7 for the passage of the cable 16.
• the slot extends in substantially the same direction as the direction 6 of the holder 5.
• the brush 9 has a recessed portion 9a for accommodating the cable 16 when it passes through the part of the holder 5 that is not slotted.
• the operation of the brush holder unit 1 may be easily inferred from the foregoing and does not require further explanation.

Landscapes

• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Motor Or Generator Current Collectors (AREA)
• Motor Or Generator Frames (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (2)

Family

ID=32088989

Family Applications (1)

Country Status (3)

Cited By (1)

Citations (4)

• 2002
  • 2002-10-11 IT ITBO20020100 patent/ITBO20020100U1/it unknown
• 2003
  • 2003-10-10 AU AU2003267739A patent/AU2003267739A1/en not_active Abandoned
  • 2003-10-10 WO PCT/IB2003/004478 patent/WO2004034517A2/en not_active Application Discontinuation

Patent Citations (4)

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