Abstract: A variable displacement hydraulic pump or motor includes: a swash plate; a lever supported by a housing and configured to rotate in conjunction of tilting of the swash plate; and a sensor configured to detect a displacement amount of the lever.

Abstract: A variable displacement hydraulic pump or motor (10) includes: a swash plate (13); a lever (22) supported by a housing (21) and configured to rotate in conjunction of tilting of the swash plate (13); and a sensor (23) configured to detect a displacement amount of the lever (22).

Abstract: A hydraulic pump/motor includes a rotational shaft rotatably attached inside a casing, a cylinder block configured to rotate together with the rotational shaft, a plurality of pistons, a swash plate, a valve plate, and a rotation detection mechanism. The rotation detection mechanism includes a detection target section having three or more recesses formed on an outer peripheral surface of the cylinder block in a unique arrangement pattern with different arc lengths between the three continuous recesses with respect to one rotational direction of the rotational shaft and being formed so as not to include the unique arrangement pattern with respect to the other rotational direction of the rotational shaft, each of the three or more recesses having a cross section having a same semicircular shape perpendicular to a direction of the rotational shaft; and a rotation sensor arranged in the casing in a state of facing the detection target section.