PUMP TORQUE CONTROL DEVICE FOR HYDRAULIC CONSTRUCTION MACHINE

摘要

A pump torque control device performing appropriate pump torque control by preventing hunting caused by interference between speed sensing control and engine speed control at low hydraulic oil temperature. A regulator (31) controls displacement volumes of hydraulic pumps (2, 3) so that absorption torque of the pumps (2, 3) does not exceed a preset maximum absorption torque. A rotation sensor (33), an oil temperature sensor (34), an electromagnetic proportional valve (35), and a controller (23) perform speed sensing control so that the maximum absorption torque of the pumps (2, 3) set at the regulator (31) is reduced corresponding to a difference between a target speed and an actual speed of the engine. A second correction coefficient calculation section (45) and control gain correction section (49) of the controller (23) change, based on a value detected by the oil temperature sensor (34), the control gain of the speed sensing control so that the gain decreases as the temperature of the hydraulic oil lowers.