Komatsu Corporation

Takeo Iida

Seiichi Hasegawa

Mitsuru Arai

Hideaki Usami

Tadashi Nakagawa

Tomohiro Sakai

An axial hydraulic pump-motor, in which a cylinder block having a plurality of cylinder bores on a valve plate having a high-pressure side port and a low-pressure side port for controlling an amount of reciprocation of a piston in each of the cylinder bores, the hydraulic pump-motor includes: a residual pressure release port provided on the valve plate and communicating until the cylinder bore on a top dead center side communicates with the low-pressure side port; a residual pressure acquisition portion obtaining a value of a residual pressure in the cylinder bore on the top dead center side; and a directional switching valve switching a flow path between the residual pressure release port and an hydraulic oil tank and a flow path between the residual pressure release port and the low-pressure side port.

Hydraulic pump-motor

An axial-type hydraulic pump/motor in which a cylinder block with a plurality of cylinder bores formed around a rotation axis slides with respect to a valve plate that has a valve plate discharge port and a valve plate suction port, and controls the amount of reciprocation of a piston in each cylinder bore depending on the inclination of a swash plate. Based on the rotational direction of the cylinder block, an opening shape of an end portion on the front side in the rotational direction of a cylinder port and an opening shape of an end portion on the rear side in the rotational direction of the valve plate suction port PBhave the same shape or partially have the same shape.

Hydraulic pump/motor

The present embodiments disclose an axial hydraulic pump including a residual pressure regenerating circuit () which is a pipe line communicating with a top dead center side communication port () and a bottom dead center side communication port (). Further, the axial hydraulic pump includes cylinder ports (-to-) which are provided in the respective cylinder bores of the cylinder block () and are operated with the rotation of the cylinder block (). Even further, the axial hydraulic pump includes communication holes (-to-) which communicate with the top dead center side communication port () and the bottom dead center side communication port ().

Hydraulic pump or motor

A pressure regulating restriction for allowing a cylinder bore and a valve plate discharge port to communicate with each other before the cylinder bore communicates with the valve plate discharge port, and an oil passage for allowing the valve plate discharge port and the cylinder bore to temporarily communicate with each other in a time period after the cylinder bore is freed from the communication with the valve plate suction port until the cylinder bore communicates with the pressure regulating restriction. The oil passage has length capable of transmitting high pressure in the oil passage on a side of the cylinder bore at the time of the communication and of restoring the pressure in the oil passage on the side of the cylinder bore to the pressure on a side of the valve plate discharge port before the communication with a next cylinder bore at the time of non-communication.

Growing community of inventors

Koga, Japan

Takeo Iida