Patent ID: 8403644

Claim:
A power generating apparatus of renewable energy type, comprising: a tower; a nacelle which is installed on a tip end part of the tower; a main shaft which is housed in the nacelle and rotates with rotor blades; a hydraulic pump which is housed in the nacelle and installed to the main shaft; a hydraulic motor which is arranged near a base end part of the tower and is driven by pressurized oil supplied from the hydraulic pump; a generator which is connected to the hydraulic motor; a first double pipe which comprises a first inner pipe and a first outer pipe and is supported on a side of the nacelle and extends inside the tower toward the base end part of the tower, the first inner pipe and the first outer pipe being connected to the hydraulic pump; and a second double pipe which comprises a second inner pipe and a second outer pipe and is arranged farther from the nacelle than the first double pipe and fit in the first double pipe, the second inner pipe and the second outer pipe being connected to the hydraulic motor; an inner bearing which is provided between the first inner pipe and the second inner pipe and supports the first inner pipe rotatably to the second inner pipe; an outer bearing which is provided between the first outer pipe and the second outer pipe and supports the first outer pipe rotatably to the second outer pipe, wherein the first and second inner pipes communicate with each other to form an inner passage, the first and second outer pipes communicate with each other to form an outer passage, high-pressure oil discharged from the hydraulic pump flows in one of the inner passage and the outer passage and is supplied to the hydraulic motor, low-pressure oil discharged from the hydraulic motor flows in the other of the inner passage and the outer passage and returns to the hydraulic pump, and the first double pipe supported on the nacelle side is connected rotatably to the second double pipe, wherein the inner bearing is slidable relative to the first inner pipe in a longitudinal direction of the first inner pipe, and the outer bears in slidable relative to the first outer pipe in a longitudinal direction of the first outer pipe.