Patent ID: 6927516

Claim:
A bearing lubricating structure of a two rotor single stator type electric motor, the motor including a fixed annular stator, a fixed rear disc that extends radially inward from a rear end portion of the stator, an annular inner rotor rotatably arranged in the stator, an annular outer rotor rotatably arranged around the stator, a hollow first rotation shaft concentrically and tightly received in the inner rotor to rotate together like a unit about a common axis, a second rotation shaft concentrically and rotatably received in the first rotation shaft, a rotor rear disc that extends radially to connect a rear end portion of the outer rotor to a rear end portion of the second rotation shaft so that the outer rotor, the rotor rear disc and the second rotation shaft rotate together like a unit about the common axis, a first bearing operatively arranged between a first portion of the rotor rear disc and the first rotation shaft and a second bearing operatively arranged between a second portion of the rotor rear disc and the stator rear disc, the bearing lubricating structure comprising: a first oil passage formed in the second rotation shaft, into which a lubrication oil is led; an annular oil space defined between the second rotation shaft and the first rotation shaft, the annular oil space being communicated with the first oil passage of the second rotation shaft; a second oil passage substantially defined by a rear end portion of the first rotation shaft, the stator rear disc and the rotor rear disc, the second oil passage having the first and second bearings received therein; a drain port provided by the rotor rear disc to connect the second oil passage with an outside of the rotor rear disc; a first oil distribution passage provided for permitting an oil flow from the second oil passage toward a space in which the stator and the inner rotor are arranged; and a second oil distribution passage provided for permitting an oil flow from the second oil passage toward a space in which the stator and the outer rotor are arranged.