Abstract: A hydraulic pump/motor includes: a cylinder block rotating about a rotation axis; a piston in a cylinder bore; and a valve plate facing a cylinder port. The valve plate includes: a high pressure port through which oil discharged from the cylinder port flows; a low pressure port through which the oil to be sucked into the cylinder port flows; a region disposed between the high and low pressure ports in a circumferential direction of the rotation axis and including a top dead center position facing the cylinder port of the cylinder bore in which the piston moved to a top dead center is disposed; and a residual pressure release port between the top dead center position and the low pressure port in the region. The residual pressure release port includes first and second ports disposed at positions different from each other in the radial direction of the rotation axis.

Abstract: The present invention provides a hat-type steel sheet pile whose economic efficiency, workability, and integrity are all optimized. In the hat-type steel sheet pile according to the present invention, web portions are continuously formed at both ends of an upper flange portion, and lower flange portions are formed at respective end portions of a pair of web portions. A relationship among geometrical moment of inertia I per 1 m of wall width (cm4/m) when forming a steel sheet pile wall, weight per unit wall area W (kg/m2), penetration resistance R, and web angle ? (°) is set to satisfy one of several expression groups.

Abstract: The present invention provides a hat-type steel sheet pile whose economic efficiency, workability, and integrity are all optimized. In the hat-type steel sheet pile according to the present invention, web portions are continuously formed at both ends of an upper flange portion, and lower flange portions are formed at respective end portions of a pair of web portions. A relationship among geometrical moment of inertia I per 1 m of wall width (cm4/m) when forming a steel sheet pile wall, weight per unit wall area W (kg/m2), penetration resistance R, and web angle ? (°) is set to satisfy one of several expression groups.