HYDRAULIC DRIVE TRAVELING SYSTEM

摘要

PCT No. PCT/JP90/00097 Sec. 371 Date Jun. 25, 1990 Sec. 102(e) Date Jun. 25, 1990 PCT Filed Jan. 26, 1990 PCT Pub. No. WO90/08910 PCT Pub. Date Sep. 8, 1990.A hydraulic drive traveling system has a pressure compensated low control valve connected between a hydraulic pump and a variable displacement type hydraulic motor for controlling a flow rate of the hydraulic fluid supplied to the motor. The flow rate is controlled in accordance with the delivery pressure of the pump and demanded traveling speed of the motor. When the delivery pressure of the pump is at a high level, the motor is shifted to a first capacity. When the delivery pressure of the pump is low, the motor is shifted to either the second capacity or the first capacity depending upon the demanded traveling speed.