PURPOSE: To reduce incurring of the power loss of a pump and to save fuel consumption by decreasing the inclination angle of a steering pump to a value lower than a usual value when at least either a pressure before a control valve for a work or that thereafter is below a given value.
CONSTITUTION: A working vehicle, such as a wheel loader, has a steering cylinder 4 driven by means of oil delivered from a steering pump 1, and a pressure oil amount is controlled by a steering valve 22 according to an operation amount of a steering wheel 21. The working vehicle also has an actuator 62 for a work driven by means of oil delivered from the pump 1, and pressure oil guided thereto is controlled by a control valve 61 for a work. In which case, pressure detecting means 36 and 37 to detect pressures before and after the control valve 61 for a work and a running speed detecting means 35 are provided. When the one of detecting pressures is below a given value, the inclination angle of the pump 1 is decreased, and a pump regulator 3 is controlled such that with the increase in a vehicle running speed, an inclination angle is further decreased.
KANAI TAKASHI
SUZUKI YOSHIKATSU
