Patent ID: 8829743

Claim:
A cooling structure of a generator motor including a coil of a stator, the coil being placed outside a rotor core in a radial direction, the cooling structure comprising: a rotor holder for rotating together with an input/output shaft of the generator motor and discharging, to outward in the radial direction by a centrifugal force, a coolant supplied from inward in the radial direction; a rotor core, supported outside the rotor holder in the radial direction, for rotating together with the rotor holder; a first blade, placed at an end in an axial direction of the rotor core, for holding one end of the rotor core; and a second blade, placed at an end in the axial direction of the rotor core, for holding the other end of the rotor core, wherein the second blade includes a recessed coolant holding portion, provided on an outer circumference of the second blade on an opposite side to the rotor core and opening inward in the radial direction, for collecting a coolant supplied from inward in the radial direction, a drain hole radially penetrating an outer circumference of the coolant holding portion for draining the coolant collected in the coolant holding portion outward in the radial direction of the second blade, and wherein the second blade has a plurality of protrusions extending in the axial direction, the protrusions being formed at the coolant holding portion at predetermined intervals in a circumference direction.