Abstract:
A hydraulic circuit device for construction machines wherein a first pressure regulator (130) for controlling the downstream pressure of first variable throttles (107, 107a) to a value corresponding to a first signal pressure is disposed between the first variable throttles of a directional control valve (47) for leftward running and a first running motor (57), and wherein a second pressure regulator (133) for controlling the downstream pressure of second variable throttles (108, 108a) to a value corresponding to a second signal pressure is disposed between the second variable throttles of a directional control valve (49) for rightward running and a second running motor (57). A negative pressure of either the first or second running motor, whichever is higher, is detected by a shuttle valve (136) as a maximum negative pressure, and signal switching valves (131, 135, 170) are caused to operate during combination operation in which the first and second running motors and at least one of a plurality of work machine actuators (53 to 56) are simultaneously driven, whereby themaximum negative pressure is imparted to the first and second pressure regulators as first and second signal pressures. Even when this enables a communication circuit (110) to be put into operation as the work machine actuators are put into operation during combination operation in which running and the operation of the work machine are simultaneously effected to thereby allow a pressure oil supply circuit (104) of the second directional control valve for rightward running and a pressure oil supply circuit (103) of the first directional control valve for leftward running to communicate with each other, differences in pressure across the first and second throttles become substantially equal to each other, thereby making it possible to secure a straight running capability.
Abstract:
Simultaneous operation efficiency in a case where a plurality of actuators are operated by one or a plurality of hydraulic pumps is improved. A delivery pressure passage (1a) of one hydraulic pump (1) and that (1a) of the other hydraulic pump (1) communicate with each other through a first short-circuit passage (39) via a pair of check valves (38, 38), and an unload valve (40) is provided in this first short circuit passage (39). The load pressure introduction passages (6, 6) on the left and right hydraulic pumps (1, 1) side communicate with each other through a second short circuit passage (36) via a pair of check valves (35, 35), and a relief valve (37) is provided in this short circuit passage (36). The unload valve (40) is unloaded by the differential pressure between the pump delivery pressure in the first short circuit passage (39) and the load pressure in the second short circuit passage (36), whereby a single relief valve (37) carries out a relieving operation both in the flow merging time and current branching time to equalize the maximum pump delivery pressures. The set pressure of the relief valve (37) can be a high level so as to relieve the valve (37) under a predetermined high load pressure and so as not to relieve the same, whereby the relieving operation can be arbitrarily controlled.
Abstract:
A fluidic logic and actuator system for outputting a displacement having a fluidic logic circuitry layer including a fluidic control input and a plurality of fluidic latching memory units. At least some of the plurality of fluidic latching memory units are configured to perform combinatorial and sequential logic functions and output a fluid response. A fluid actuator layer is provided having a plurality of fluid actuators, wherein each of the plurality of fluid actuators being movable in response to the fluid response of a corresponding one of the plurality of fluidic latching memory units.
Abstract:
본 명세서의 일 실시예는 동작 모드 변경에 대한 굴삭기의 유압펌프 제어방법에 관한 것으로, 작업자의 조작에 따라 동작신호를 발생시키며 조이스틱 또는 패달을 포함하는 조작부와, 상기 동작신호에 대응하는 복수의 액추에이터를 구동시키기 위해 상기 액추에이터에 유량을 공급하고, 복수의 펌프와 복수의 로직밸브를 포함하는 유량 공급부 및 상기 동작신호에 따라 정해진 동작 모드의 변경에 대하여 액추에이터의 사용 빈도와 부하를 고려한 동작별 우선순위 알고리즘을 이용하여 상기 유량 공급부를 제어하는 제어부를 포함하는 것을 특징으로 한다.
Abstract:
An online method for reconfiguring pressure and position sensors in a hydraulic system is disclosed. In one step, a sensor drift condition, a recalibration request, or an unisolated fault condition is detected. In another step, a system pressure sensor or another sensor, such as a load-sense pressure sensor, is verified as a trusted master reference sensor. Another step includes measuring and recording a first pressure reading at the master reference sensor and first voltage readings associated with first, second, third, and fourth pressure slave sensors at a first pump pressure set point. Another step includes, repeating the previous step at a second pump pressure set point. A new gain and offset for each of the first, second, third, and fourth pressure sensors can be calculated based on a comparison of the recoded first and second pressure readings and the recorded first and second voltage readings.
Abstract:
There is disclosed an actuator (5) having an actuator chamber (6) and actuator piston (9) therein defining an extend chamber (10) and a retract chamber (7) separated from the extend chamber by the actuator piston. A first fluid pump (A) is in fluid communication with the extend chamber and the retract chamber and is arranged to transfer therebetween volumes of fluid substantially equal in magnitude to changes in the volume of the retract chamber resulting from movement of the actuator piston within the actuator chamber. A second pump B connected to the extend chamber and to an accumulator (17) allows the differential volume between the extend and retract chambers to be displaced into the accumulator at a pressure. Stored accumulator fluid pressure enables pump B to be back-driven so that it behaves as a motor whenever the pressure in conduit 15 is less than in conduit 16. A pre-charge (20) unit pressurises the system until full mass counterbalance of the suspended load is achieved. In this state little or no input power from the servo motor (via pumps A & B) will be needed and significant energy savings can be made.