Patent ID: 8030810

Claim:
An automotive electric machine including: a stator; a rotor that is rotationally mounted coaxially to the stator and inside the stator to rotate about a rotation axis; a shaft that is rotationally mounted about the rotation axis, supports the rotor, and is hollow inside so as to have a longitudinal, central cooling channel filled with a cooling fluid; at least a first pushing element that is arranged inside the cooling channel to rotate with the shaft about the rotation axis and to define at least one worm which extends within the cooling channel along the rotation axis to push the cooling fluid along the rotation axis and in a first direction due to its rotation; and at least a second pushing element that is concentrically arranged inside the first pushing element to rotate with the shaft about the rotation axis and to define at least one worm which extends within the cooling channel along the rotation axis to push the cooling fluid along the rotation axis and in a second direction opposite to the first direction.