Electric motor/generator with easily replaceable brush holder and brushes

1. An electrical machine ( 1 ) comprising a machine housing ( 5 ) receiving an electrically excited rotor ( 2 ) and a stator ( 10 ), wherein the rotor ( 2 ) is arranged on a rotor shaft ( 4 ) for rotation about an axis of rotation ( 19 ), and an electronics unit ( 18 ) having a housing ( 28 ) fastened to the machine housing ( 5 ) on a first end of the machine housing ( 5 ), wherein the machine housing ( 5 ) is at least partially made up of first and second bearing plates ( 6 , 7 ), in which are respectively fastened, first and second bearings ( 8 , 9 ) for bearing the rotor shaft ( 4 ), wherein the electronics unit ( 18 ) is electrically connected to an exciter winding ( 3 ) of the rotor ( 2 ) via at least one sliding contact ( 11 , 12 ), the sliding contact including at least one slip ring ( 13 , 14 ) assigned to the rotor ( 2 ) and at least two brushes ( 15 , 16 ) assigned to the electronics unit ( 18 ), the at least two brushes ( 15 , 16 ) being arranged displaceably in a brush holder ( 20 ) and spaced apart axially relative to the axis of rotation ( 19 ), wherein the brush holder ( 20 ) is fastened exchangeably in a guiding recess ( 27 ) formed in the housing ( 28 ) of the electronics unit ( 18 ) to facilitate removal of the brush holder ( 20 ) and exchange of the at least two brushes ( 15 , 16 ) without disassembly of the electronics unit ( 18 ) and without separation of the electronics unit housing ( 28 ) from the machine housing ( 5 ), wherein the brush holder ( 20 ) further comprises contacts ( 37 , 38 ), each contact ( 37 , 38 ) formed as a contact bar and having an internally-threaded nut ( 45 , 46 ) aligned with a respective cavity, the respective cavities being spaced apart in a circumferential direction of the housing ( 28 ) of the electronics unit ( 18 ), the nuts ( 45 , 46 ) being axially spaced from the at least two brushes ( 15 , 16 ), and a groove being located between the contacts ( 37 , 38 ), and wherein the electronics unit ( 18 ) is fastened to the first bearing plate ( 6 ) of the machine housing ( 5 ).

2. The electrical machine according to claim 1 , characterized in that the fastening of the brush holder ( 20 ) in the guiding recess ( 27 ) is with non-positive or positive engagement.

3. The electrical machine according claim 2 , characterized in that a positively engaging connection is established by a latching connection ( 29 ) having a latching element ( 30 ) and a latching counter-element ( 31 ).

4. The electrical machine according to claim 1 , characterized in that an electrical connection between the electronics unit ( 18 ) and the brush holder ( 20 ) is established via a screw connection ( 32 ).

5. The electrical machine according to claim 4 , characterized in that the screw connection ( 20 ) comprises at least one screw ( 33 , 34 ), which is arranged in an axial direction or a radial direction.

6. The electrical machine according to claim 1 , characterized in that an electrical connection between the electronics unit ( 18 ) and the brush holder ( 20 ) is established by means of a positively engaging connection.

7. The electrical machine according to claim 1 , characterized in that there are a number of guiding recesses ( 27 ), which are arranged offset in a circumferential direction and respectively receive at least one brush holder ( 20 ).

8. The electrical machine according to claim 1 , characterized in that the electronics unit ( 18 ) is fastened to the first bearing plate ( 6 ) of the machine housing ( 5 ) on a side of the first bearing plate ( 6 ) facing away from the second bearing ( 9 ) so that the at least two brushes ( 15 , 16 ) are not located axially between the first and second bearings ( 8 , 9 ).