Patent ID: 8347619

Claim:
A system for controlling torque of plural variable displacement hydraulic pumps in construction equipment, comprising: an engine; at least two variable displacement hydraulic pumps associated with the engine; hydraulic actuators associated with the hydraulic pumps, respectively, to drive working devices; control levers generating manipulation signals corresponding to manipulation amounts to drive the hydraulic actuators, respectively; control lever sensing means detecting the manipulation amounts of the control levers and generating detection signals; hydraulic pump pressure sensing means detecting load pressures of the hydraulic pumps and generating detection signals; maximum torque setting means setting the total torque inputted from the engine to the hydraulic pumps; desired flow rate computing means computing flow rates of the hydraulic pumps corresponding to the detection signals inputted from the control lever sensing means; expected torque computing means computing expected torque values of the hydraulic pumps in accordance with input signals from the hydraulic pump pressure sensing means and the desired flow rate computing means; torque distributing means distributing torque values of the hydraulic pumps by proportionally reducing allowable torque values of the hydraulic pumps so that the sum of the torque values generated by the hydraulic pumps is limited to the torque value by the maximum torque setting means in accordance with input signals from the expected torque computing means and the maximum torque setting means; limited flow rate computing means receiving the torque values of the hydraulic pumps distributed by the torque distributing means and the load pressures of the hydraulic pumps from the hydraulic pump pressure sensing means, and computing the flow rates of the hydraulic pumps so that the torque values reset in accordance with the load pressures generated by the hydraulic pumps are generated in the hydraulic pumps; and output means outputting control signals to regulators so that the hydraulic pumps are operated in accordance with the flow rates computed by the limited flow rate computing means.