ROTOR FOR AN ELECTRIC MACHINE WITH A MECHANICAL FIXATION OF ROTOR MAGNETS
A rotor for an electric machine includes a rotor lamination stack having a cavity, and a rotor magnet with a substantially rectangular cross section being arranged in the cavity. At least some of the rotor laminations include a spring tongue, which is unbent and reaches into a space provided for the rotor magnet in the unmounted state of the rotor magnet and which is bent and imposes an oblique force on the same in the mounted state of the rotor magnet based on elastic deformation. The oblique force is directed in an angle (α) of 0°>α>90° to longitudinal sides of the rectangular cross section of the rotor magnet. The stator and rotor may be implemented in an electric machine or a vehicle with the electric machine.
1 . Rotor for an electric machine, comprising
a rotor lamination stack with a plurality of rotor laminations stacked over one another in an axial direction, wherein the rotor laminations form a cavity for a rotor magnet, and
a rotor magnet, which is arranged in said cavity and which has a substantially rectangular cross section,
wherein
at least some of the rotor laminations comprise a spring tongue, which is unbent and reaches into a space provided for the rotor magnet in the unmounted state of the rotor magnet and which is bent and which imposes an oblique force on the same in the mounted state of the rotor magnet based on elastic deformation of the spring tongue, wherein
the oblique force is directed in an angle of 0°>α>90° to longitudinal sides of the rectangular cross section of the rotor magnet.
2 . Rotor as claimed in claim 1 , wherein the spring tongue in the mounted state of the rotor magnet is bent
a) in axial direction or
b) transversal to the axial direction.
3 . Rotor as claimed in claim 2 , wherein the spring tongue in case a)
A) projects in a projecting direction at an angle (α) of 0°>α>90° to longitudinal sides of the rectangular cross section of the rotor magnet and has an end, which is oriented perpendicular to its projecting direction, or
B) projects in a projecting direction parallel to one of the longitudinal sides of the rectangular cross section of the rotor magnet and has an end, which is angled in view of the projecting direction, or
C) projects in a projecting direction at an angle α of 0°>α>90° to longitudinal sides of the rectangular cross section of the rotor magnet and has an end, which is angled in view of the projecting direction.
4 . Rotor as claimed in claim 1 , wherein a rotor lamination of the rotor laminations comprises
i) a single spring tongue imposing the oblique force on the rotor magnet or
ii) a plurality of spring tongues imposing forces on the rotor magnet including the oblique force.
5 . Rotor as claimed in claim 1 , wherein a rotor lamination of the rotor laminations comprises a leaf spring imposing an additional force on the rotor magnet which is directed in parallel with two of longitudinal sides of the rectangular cross section of the rotor magnet.
6 . Rotor as claimed in claim 1 , wherein the spring tongue in the unbent state has
I) a curved cross section or
II) a straight cross section.
7 . Rotor as claimed in claim 1 , wherein all rotor laminations of the rotor lamination stack comprise a spring tongue.
8 . Rotor as claimed in claim 1 , wherein all rotor laminations of the rotor lamination stack are identical.
9 . Rotor as claimed in claim 1 , wherein the oblique force points radially outwards or has a radial component pointing outwards.
10 . Rotor as claimed in claim 1 , wherein the rotor magnet is pressed into an outer corner of the cavity by the spring tongue.
11 . Rotor as claimed in claim 1 , wherein the spring tongue is formed by punching.
12 . Rotor as claimed in claim 1 , wherein a gap between the rotor lamination stack and the rotor magnet is filled with a potting compound.
13 . Rotor as claimed in claim 1 , wherein a plurality of cavities corresponding to said cavity for the rotor magnet, a plurality of rotor magnets corresponding to said rotor magnet and a plurality of spring tongues corresponding to said spring tongue, wherein one rotor magnet is arranged in one cavity each.
14 . Electric machine, comprising
a stator and
a rotor according to claim 1 , which is rotatably arranged relative to the stator.
15 . Vehicle with a drive train comprising an electric machine according to claim 14 , which is provided to propel the vehicle.
16 . Rotor as claimed in claim 2 , wherein a rotor lamination of the rotor laminations comprises
i) a single spring tongue imposing the oblique force on the rotor magnet or
ii) a plurality of spring tongues imposing forces on the rotor magnet including the oblique force.
17 . Rotor as claimed in claim 2 , wherein a rotor lamination of the rotor laminations comprises a leaf spring imposing an additional force on the rotor magnet which is directed in parallel with two of longitudinal sides of the rectangular cross section of the rotor magnet.
18 . Rotor as claimed in claim 2 , wherein the spring tongue in the unbent state has
I) a curved cross section or
II) a straight cross section.
19 . Rotor as claimed in claim 2 , wherein all rotor laminations of the rotor lamination stack comprise a spring tongue.
20 . Rotor as claimed in claim 2 , wherein all rotor laminations of the rotor lamination stack are identical.