End plate for an electric machine, electric machine and method for assembling an electric machine

1. An end plate ( 30 ) for an electric machine ( 1 ), the end plate comprising:

a magnetic bearing ( 80 ) configured to rotatably mount a rotor ( 20 ) of the electric machine ( 1 );

a bearing receptacle ( 40 ), configured to accommodate the magnetic bearing ( 80 ) therewithin; and

a radially outer circumferential contour ( 50 ), on which at least three support elements ( 60 , 70 ) are provided, each of which protrudes radially outside, with respect to the circumferential contour ( 50 ), by a protruding amount (M) so as to define a discontinuous outer circumferential contour of the end plate ( 30 ), the at least three support elements ( 60 , 70 ) being detachably fastened to the end plate ( 30 ) by fasteners ( 63 , 73 ), the fasteners ( 63 , 73 ) being arranged so as to be circumferentially orientated along the circumferential contour of the end plate ( 30 ),

wherein the respective protruding amounts (M) of the at least three support elements ( 60 , 70 ) are dimensioned so that the end plate ( 30 ) is fitted in by making a center of the magnetic bearing ( 80 ) coincide with at least one of a geometrical longitudinal axis (A 2 ) of the electric machine ( 1 ) and a magnetic longitudinal axis (A 4 ) of the electric machine ( 1 ),

wherein the electric machine ( 1 ) comprises a stator ( 10 ) having a stator housing ( 11 ) having an inner circumference ( 12 ), and wherein the support elements ( 60 , 70 ) are arranged in two groups of support elements distributed about the circumferential contour ( 50 ), wherein the support elements of a first group of the two groups are in engagement with the inner circumference ( 12 ) of the stator housing ( 11 ) so as to fit in the end plate ( 30 ) with respect to the stator housing ( 11 ), and wherein the support elements of a second group of the two groups are in engagement with an inner circumference ( 101 ) of a connecting housing ( 100 ) so as to fit in the connecting housing ( 100 ) with respect to the stator housing ( 11 ) independently of the end plate ( 30 ), and

wherein the support elements ( 60 , 70 ) each have a support surface ( 61 a , 71 a ) located radially at the outermost side of the respective support elements, which are formed stepped axially of the end plate ( 30 ), wherein the stepping of the first group with at least three support elements ( 60 ) radially rises in a first axial direction (AR 1 ), perpendicular to the circumferential orientation of the fasteners ( 63 ) for the first group, as far as to the respective protruding amount (M) and the stepping of the second group with at least three support elements ( 70 ) radially rises in a second axial direction (AR 2 ), perpendicular to the circumferential orientation of the fasteners ( 73 ) for the second group, as far as to the respective protruding amount (M), and wherein within each of the two groups the support elements ( 60 , 70 ) are arranged with a defined angular spacing from one another distributed about the circumferential contour ( 50 ).

2. The end plate ( 30 ) according to claim 1 , wherein the support elements ( 60 , 70 ) are each mounted radially adjustably on the circumferential contour ( 50 ) so that the respective protruding amounts (M) of the support elements ( 60 , 70 ) are adjustable.

3. The end plate ( 30 ) according to claim 1 , wherein each support element ( 60 , 70 ) comprises: a contact body ( 61 , 71 ) located radially to the outside and configured to contact an inner circumference ( 12 ) of the stator housing ( 11 ), and an individual number of shims ( 62 , 72 ) shimmed under the contact body ( 61 , 71 ) radially to the inside, each shim ( 62 , 72 ) having a specific radial thickness dimension.

4. The end plate ( 30 ) according to claim 1 , further comprising respective recesses ( 51 ), each of which extends from the circumferential contour ( 50 ) radially to the inside and circumferentially of the end plate ( 30 ), wherein the support elements ( 60 , 70 ) are arranged in the respective recesses ( 51 ).

5. The end plate ( 30 ) according to claim 1 , wherein within each of the two groups the support elements ( 60 , 70 ) are configured so as to be symmetrically distributed about the circumferential contour ( 50 ).

6. An electric machine ( 1 ) comprising:

a stator ( 10 ) having a stator housing ( 11 );

a rotor ( 20 ) arranged in an inner circumference ( 12 ) of the stator housing ( 11 ); and

an end plate ( 30 ) according to claim 1 ,

wherein for rotatably mounting the rotor ( 20 ), the magnetic bearing ( 80 ) is received in the bearing receptacle ( 40 ) of the end plate ( 30 ), and for radially supporting the end plate ( 30 ) the outer circumferential contour is fitted into the inner circumference ( 12 ) of the stator housing ( 11 ) such that the center of the magnetic bearing ( 80 ) is fitted in with at least one of a geometrical longitudinal axis (A 2 ) of the electric machine ( 1 ) and a magnetic longitudinal axis (A 4 ) of the electric machine ( 1 ).

7. The electric machine ( 1 ) according to claim 6 , wherein the rotor ( 20 ) comprises a rotor shaft ( 21 ), and wherein the magnetic bearing ( 80 ) has an active magnetic bearing with a catch bearing, having an inner ring, which encloses the rotor shaft ( 21 ) and which has an inner diameter that is greater by a predetermined dimension than an outer diameter of the rotor shaft ( 21 ), so that in the case of an energized magnetic bearing ( 80 ) an annular gap between the rotor shaft ( 21 ) and the inner ring of the catch bearing is formed and in the case of a non-energized magnetic bearing ( 80 ) the rotor shaft ( 21 ) rests on an inside of the inner ring.

8. The electric machine ( 1 ) according to claim 7 , further comprising a control device ( 90 ) configured to electrically activate the magnetic bearing ( 80 ), so that in the case of an energized magnetic bearing ( 80 ) an axis of rotation of the rotor shaft ( 21 ) coincides with the center (A 1 ) of the magnetic bearing.

9. A method for assembling an electric machine ( 1 ) according to claim 7 , the method comprising:

inserting the rotor ( 20 ) in the stator housing ( 11 );

fitting the outer circumferential contour of the end plate ( 30 ) into the inner circumference ( 12 ) of the stator housing ( 11 ), so that the magnetic bearing ( 80 ) and the inner ring of the catch bearing enclose the rotor shaft ( 21 );

operating the electric machine ( 1 ) so that its rotor ( 20 ) with an energized magnetic bearing ( 80 ) rotates;

determining a vibration behavior of the rotor ( 20 );

determining a correction offset from the vibration behavior; and

changing the respective protruding amounts (M) of the support elements ( 60 , 70 ) based on the correction offset.