Abstract: A hydraulic pump unit includes a cylindrical member that is fit into an outer circumference of the main shaft and a hydraulic pump body arranged on an outer circumferential side of the cylindrical member. The hydraulic pump body includes a ring cam mounted on the outer circumference of the cylindrical member, a pump bearing, a pump housing, a plurality of pistons housed in the pump housing and actuated by the ring cam, and a plurality of cylinders which guide the plurality of pistons in a radial direction and are arranged in a circumferential direction. The hydraulic pump unit is configured such that the pump unit is insertably fixed to the main shaft by the cylindrical member.

Abstract: A power generating apparatus includes a rotating shaft, a hydraulic pump driven by the rotating shaft, a hydraulic motor driven by pressurized oil supplied from the hydraulic pump, and a generator coupled to the hydraulic motor. Each of the hydraulic pump and motor includes working chambers each defined by a cylinder and a piston, a high pressure manifold and a low pressure manifold. Each of the high and low pressure manifolds includes branch channels connected to the working chambers and a merging channel connected to a high or low pressure oil line. The branch channels are equipped with high or low pressures valves, joined together and merged into the merging channel.

Abstract: An object of the present invention is to provide a hydraulic pump structure which improves the ease of mounting the hydraulic pump on the main shaft, and a method of mounting the hydraulic pump which can be performed in a simplified manner. A hydraulic pump unit 10 is formed by unitizing a cylindrical member 46 fit into an outer circumference of the main shaft 12 and a hydraulic pump body 76 arranged on an outer circumferential side of the cylindrical member 46. The hydraulic pump body 76 comprises a ring cam 52 mounted on the outer circumference of the cylindrical member 46, a pump bearing 54, a pump housing 34, a plurality of piston 58 housed in the pump housing 34 and actuated by the ring cam, and a plurality of cylinders 60 which guide the plurality of pistons in a radial direction and are arranged in a circumferential direction, and the hydraulic pump unit 10 is configured such that the pump unit 10 is insertably fixed to the main shaft 12 by the cylindrical member 46.