초록 ▼

A drive system for construction machinery in which hydraulic circuit is provided with a plurality of variable-displacement hydraulic pumps and a plurality of hydraulic actuators, each pump being connected in closed circuit to one or a plurality of the actuators via a solenoid-operated valve or valve

A drive system for construction machinery in which hydraulic circuit is provided with a plurality of variable-displacement hydraulic pumps and a plurality of hydraulic actuators, each pump being connected in closed circuit to one or a plurality of the actuators via a solenoid-operated valve or valves to drive a movable member or members connected to the actuator or respective actuators when pressurized fluid is supplied to the actuator or actuators from the pump. At least one of the selected hydraulic actuators is further connected in closed circuit through a solenoid-operated valve to at least one of the hydraulic pumps other than the hydraulic pump which is connected in closed circuit to the hydraulic actuator. The hydraulic circuit means is controlled such that timing for switching the solenoid-operated valves is controlled in conjunction with the operation of the pump so as to absorb the shock which would otherwise be produced when each actuator is rendered operative and inoperative. The hydraulic circuit means is further controlled such that, when the operation speed of each hydraulic actuator is increased or reduced including the time at which the actuator is rendered operative and inoperative, the speed is adjusted in conformity with the inertia and operation characteristics of a movable member connected to the actuator.

대표청구항 ▼

A method of controlling hydraulic circuit means of a drive system for construction machinery in which said hydraulic circuit means includes a plurality of variable-displacement hydraulic pumps and a plurality of hydraulic actuators, each said pump being connected in closed circuit to one or a plural

A method of controlling hydraulic circuit means of a drive system for construction machinery in which said hydraulic circuit means includes a plurality of variable-displacement hydraulic pumps and a plurality of hydraulic actuators, each said pump being connected in closed circuit to one or a plurality of said actuators through a solenoid-operated valve or valves to drive a movable member or members connected to the actuator or respective actuators when pressurized fluid is supplied to the actuator or actuators from the pump, at least one of the selected hydraulic actuators being further connected in closed circuit through a solenoid-operated valve to at least one of the hydraulic pumps other than the hydraulic pump which is connected in closed circuit to the selected hydraulic actuator, characterized in that said method comprises the steps of: setting a preprogrammed priority order of hydraulic communication between each hydraulic pump and the hydraulic actuators to which said hydraulic pump is connected in closed circuit through the respective solenoid-operated valves generating command signals by an operator; closing all of said solenoid-operated valves when no command signals for driving said actuators are produced; when a command signal for driving at least one actuator is produced, opening the solenoid-operated valve associated with said one actuator or the actuator higher in the priority order of hydraulic communication with said hydraulic pump while controlling the delivery of the pump by the command signal for driving the actuator with which said opened valve is associated; when at least one of command signals which have been produced to drive at least one actuator is removed, closing the solenoid-operated valve associated with the actuator which have been driven by the removed command signal and/or opening or keeping open the solenoid-operated valve associated with the other actuator or actuator higher in the priority order of hydraulic communication with said hydraulic pump among the other actuators while controlling the delivery of the pump by the command signal for driving the actuator with which said opened or opening-kept valve is associated; and conducting any switching of each said solenoid-operated valve only when the delivery of said pump is zero or has been reduced substantially to zero.