| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a torque control device for a variable displacement type hydraulic pump capable of maintaining a suitable relationship between an engine output torque and a pump absorption torque upon operation of construction machinery on highland. <P>SOLUTION: A torque change control means equipped to a hydraulic shovel for changing the pump absorption torque according to a signal outputted from a selector switch 13 which is a manual selecting device includes a means for controlling to reduce the pump absorption torque of a first hydraulic pump 2 to, for example, 78% according to a predetermined altitude, when the altitude of the operation site of the hydraulic shovel is at, for example, the predetermined altitude of about 5,000m above sea level. The means is equipped with an electormagnetic selector valve 11 for controlling a first regulator 5 of the first hydraulic pump 2, and a controller 12 for controlling the drive of the electromagnetic selector valve 11 according to a signal outputted from a selector switch 13. <P>COPYRIGHT: (C)2004,JPO |
