Rotor for an electric machine having a retaining device for the end winding

1. A rotor for an electric machine comprising:

a rotor yoke having a plurality of axial winding slots distributed on an outer periphery of the rotor yoke;

a winding bar disposed in one of the plurality of axial winding slots, the winding bar having at least one winding end emerging axially from the rotor yoke so as to form an end winding;

a retaining device including a plurality of radial bolts, each of the plurality of radial bolts having a head fixedly connected to a shank, the retaining device including a retaining strip extending in an axial direction against the end winding and the plurality of radial bolts being arranged in series in the axial direction and configured to press the retaining strip against the end winding, wherein the retaining device retains the end winding against a centrifugal force acting on the end winding;

at least one hammer-shaped recess configured to receive at least one counter strip having a threaded hole configured to receive one of the plurality of radial bolts so as to fasten the respective bolt on an outer periphery of an axial extension of the rotor yoke, wherein the axial extension is disposed inside the end winding, and wherein each of the plurality of radial bolts associated with each retaining strip is screwed into a common counter strip; and

a locking strip configured to lock the plurality of radial bolts against rotation, wherein each of the plurality of radial bolts include a recess with a rectangular locating face disposed on an inner end of each of the plurality of radial bolts, the locking strip being axially inserted into the recess and disposed against the rectangular locating face.

2. The rotor as recited in claim 1 , wherein each head of the plurality of radial bolts is materially bonded to the shank.

3. The rotor as recited in claim 2 , wherein each head of the plurality of radial bolts is welded to the shank.

4. The rotor as recited in claim 1 , wherein each head of the plurality of radial bolts has an aerodynamic shape.

5. The rotor as recited in claim 4 , wherein each head of the plurality of radial bolts has a rounded upper side and two straight flanks on opposite sides for drawing up the respective radial bolt.

6. The rotor as recited in claim 1 , wherein the retaining strip includes at least one rounded longitudinal edge so as to improve aerodynamics.

7. A rotor for an electric machine comprising:

a rotor yoke having a plurality of axial winding slots distributed on an outer periphery of the rotor yoke;

a winding bar disposed in one of the plurality of axial winding slots, the winding bar having at least one winding end emerging axially from the rotor yoke so as to form an end winding; and

a retaining device including a plurality of radial bolts, each of the plurality of radial bolts having a head fixedly connected to a shank, the retaining device including a locking strip configured to lock the plurality of bolts against rotation, wherein the retaining device retains the end winding against a centrifugal force acting on the end winding, and wherein each of the plurality of radial bolts include a recess with a rectangular locating face disposed on an inner end of each of the plurality of radial bolts, the locking strip being axially inserted into the recess and disposed against the rectangular locating face.

8. The rotor as recited in claim 7 , wherein the retaining device includes a retaining strip extending in an axial direction against the end winding, the plurality of radial bolts being arranged in series in the axial direction and configured to press the retaining strip against the end winding.