Patent ID: 8622719

Claim:
A hydraulic pump structure for a wind turbine generator or a tidal current generator which comprises a hub equipped with a plurality of blades, a main shaft connected to the hub and a hydraulic pump mounted on the main shaft, the hydraulic pump structure comprising: a hydraulic pump unit including a cylindrical member, which is fit onto an outer circumference of the main shaft, and a hydraulic pump body, which is arranged on an outer circumferential side of the cylindrical member to be attached to the main shaft via the cylindrical member, the hydraulic pump body being unitized with the cylindrical member to form the hydraulic pump unit, wherein the hydraulic pump body comprises: a ring cam is mounted on the outer circumference of the cylindrical member; a pump bearing mounted on the outer circumference of the cylindrical member; a pump housing supported by the cylindrical member rotatably with respect to the cylindrical member via the pump bearing; a plurality of pistons, which is housed in the pump housing and is configured to be actuated by the ring cam that is rotatable with the main shaft; and a plurality of cylinders, which guides the plurality of pistons in a radial direction and is arranged in a circumferential direction, wherein the hydraulic pump unit is configured such that the cylindrical member unitized with the hydraulic pump body is insertably fixed to the main shaft, wherein the cylindrical member has a large diameter section and small diameter sections disposed on both ends of the large diameter section, the ring cam is arranged on an outer circumferential side of the large diameter section, and the pump bearing is mounted on stepped portions between the large diameter section and the small diameter sections.