US Patent 7777378 Electric rotating machine

A shield member (90) is arranged on the rotor end face (18a) of an electric rotating machine (10). As the rotational velocity of a rotor (18) increases, the shield member (90) moves outward in the radial direction of a rotating shaft (12) to cover a part of the opening (86) of a slot (82). The shield member (90) controls inflow of lubricant from a portion in the axial-direction of the rotating shaft (12) on the outside of the rotor end face (18a) to the slot (82). Rotational resistance of the rotor (18) caused by stirring of lubricant can be reduced during high velocity rotation of the rotor (18).