HST DRIVE CIRCUIT

摘要

An HST drive circuit containing an HST pump and an HST motor individually in a pump case and a motor case, wherein the HST drive circuit can be cooled efficiently. A cooling line is formed to discharge relief oil from a charging circuit (9) for replenishing an HST closed circuit (5) with pressure oil into the pump case (3) and to feed the discharged oil to an oil tank (7) through the pump case (3), communicating piping (14), the motor case (4), and an oil cooler (16), and working oil circulating through the HST pump (1), the HST motor (2), and the HST closed circuit (5) is cooled by the oil flowing through the cooling line.