| 摘要 |
<p>Described herein is a hydraulic pump control circuit for travelling construction machine, the circuit being of the type including various hydraulic actuators divided into two groups to be driven by first and second pumps (11, 12), respectively, left and right vehicle drive motors provided in the respective groups, and a charge-over valve located on the discharge side of the first and second pumps (11, 12) and switchable to a position for supplying the oil pressure from the second pump (12) in parallel to the left and right vehicle drive motors. According to the invention, the control circuit is provided with a pilot proportioning valve (28) located between a discharge flow rate control regulator for the second pump (12) and a pilot pressure source, and means for applying the pilot pressures acting on left and right vehicle drive valves to pilot ports of the pilot proportioning valve (28), the proportioning valve (28) being operated by the sum of the pilot pressures applied to the pilot ports to produce a control pressure for the second pump regulator (14 min ).</p> |
