Patent ID: 8205719

Claim:
A hybrid working machine comprising: a generator-motor adapted to be operated by an engine; a hydraulic pump having a rotating shaft coupled directly to a rotating shaft of said generator-motor by spline coupling; and a shaft lubricating device for lubricating a spline coupling portion coupled by said spline coupling, wherein said shaft lubricating device comprises an oil passage allowing working oil present within said hydraulic pump to circulate through a route including said spline coupling portion, said oil passage being formed within a casing for covering said spline coupling portion, said oil passage comprising: a lubricating oil chamber formed within a motor casing of said motor-generator, said lubricating oil chamber communicating with said spline coupling portion, an oil chamber in a pump casing of said hydraulic pump, said oil chamber of said hydraulic pump extending radially outward of the outer periphery of said rotating shaft of said hydraulic pump, and an oil passing hole formed in the pump casing of said hydraulic pump, the oil passing hole communicating between said lubricating oil chamber formed within the motor casing of said motor-generator and said oil chamber of said hydraulic pump, the oil passing hole extending along a portion radially external of the outer periphery of said rotating shaft of said hydraulic pump.