Abstract:
A linear actuator system includes a linear actuator and at least one proportional control valve and at least one pump connected to the linear actuator to provide fluid to operate the linear actuator. The at least one pump includes at least one fluid driver having a prime mover and a fluid displacement assembly to be driven by the prime mover such that fluid is transferred from the pump inlet to the pump outlet. The linear actuator system also includes a controller that establishes at least one of a speed and a torque of the at least one prime mover and concurrently establishes an opening of the at least one proportional control valve to adjust at least one of a flow and a pressure in the linear actuator system to an operational set point.
Abstract:
An intermittent air discharge apparatus has a main valve and a pilot valve, the main valve being switched between a discharge state and a discharge stop state. The pilot valve is switched between an air-supply state to supply air to a pilot chamber for air-discharge, and an air-supply stop state. When the pilot valve is switched to the air-supply state, an exhaust passage communicates with the pilot chamber for air-discharge. When the pilot valve is switched to the air-supply state, a supply or exhaust passage allows an air supply passage to communicate with the pilot chamber for air-discharge and a pilot chamber for stopping air-supply; when the pilot valve is switched to the air-supply stop state, communication with the air supply passage is blocked. A flow rate of air from the pilot chamber for air-discharge is set by the exhaust passage, and a flow rate of air from the pilot chamber for stopping air-supply is set by the supply or exhaust passage.
Abstract:
To provide a work machine capable of efficiently regenerating the energy owned by hydraulic fluid during a swing deceleration. In the present invention, when a swing deceleration detection section 57a detects the state of a revolving upperstructure 102 being decelerated, when an operation judgment section 57c judges the state that a double-tilting pump/motor 14 is not supplying hydraulic fluid to any of a boom cylinder 1 and an arm cylinder 3, and when the number of double-tilting pumps/motors 14, 18 having supplied hydraulic fluid to a swing hydraulic motor 7 in the state before the swing deceleration detection section 57a detects the state of the revolving upperstructure 102 being decelerated is equal to one or more, a pump valve control section 57d controls changeover valves 43a, 45b, 45d, 49d to open and increases the displacements of the double-tilting pumps/motors 14, 18 to the side to make suction pressures become higher than discharge pressures of the double-tilting pumps/motors 14, 18 so that the double-tilting pumps/motors 14, 18 operate as motors.
Abstract:
A hydraulic system control unit, a hydraulic system and a working machine for controlling a hydraulic system adapted to perform at least one hydraulic work function in a working machine are provided. The hydraulic system performs the hydraulic control function in accordance with an operation signal determined by a hydraulic system control unit. In a first step the control unit receives an operator control input associated to the work function. In a second step the control unit receives a load input indicative of a load associated to the work function. Moreover, in a third step the control unit determines the operation signal in response to the operator control input and the load input.
Abstract:
The hybrid excavator includes: a first detection sensor for detecting an RCV-manipulated quantity; a second detection sensor for detecting the rotational speed of an electric motor; a hydraulic pump-motor connected to the electric motor; a hydraulic cylinder connected to the hydraulic pump-motor; first and second hydraulic valves installed in first and second passages, respectively, between the hydraulic pump-motor and the hydraulic cylinder; a third hydraulic valve for compensating for or bypassing a flow rate and a controller for receiving an RCV-manipulation signal from the first detection sensor and the rotational speed of the electric motor from the second detection sensor to compare the received values to data of previously stored working conditions, to output a control signal for switching the first and second hydraulic valves, and to block a working fluid from returning into the hydraulic cylinder, so as to thereby quickly stop the working device.
Abstract:
A hydraulic system is disclosed. The hydraulic system may have a first circuit fluidly connecting a first pump to a swing motor and to a first travel motor in a parallel closed-loop manner. The hydraulic system may also have a second circuit fluidly connecting a second pump to a second travel motor and to a first linear tool actuator in a parallel closed-loop manner.
Abstract:
A system that is usable with a well may include a piston, a primary control subsystem and an override subsystem. The piston actuates the downhole tool, and the primary control subsystem may be connected to at least one hydraulic line in order to move the piston in response to pressure that is communicated to the tool via the hydraulic line(s). The override subsystem may be connected to the hydraulic line(s) to override the primary control subsystem and move the piston in response to pressure communicated to the tool via the hydraulic line(s).
Abstract:
A system that is usable with a well may include a piston, a primary control subsystem and an override subsystem. The piston actuates the downhole tool, and the primary control subsystem may be connected to at least one hydraulic line in order to move the piston in response to pressure that is communicated to the tool via the hydraulic line(s). The override subsystem may be connected to the hydraulic line(s) to override the primary control subsystem and move the piston in response to pressure communicated to the tool via the hydraulic line(s).
Abstract:
In a hydraulic driving device for an operating machine, when an output value of an operating device is in a first predetermined range, a pump is stopped and each of an open and closed valve and a hydraulic control valve is closed. When the output value goes beyond the first predetermined range, the pump is started and the open and closed valve is opened. When the output value goes beyond a second range greater than the first predetermined range, the hydraulic control valve is opened to supply a hydraulic fluid to an actuator.
Abstract:
A drive for a movable part, such as a mold closure platen, includes two hydraulic cylinder-and-piston units defining first and third pressure chambers in a first of the hydraulic units and defining fourth and fifth pressure chambers in a second of the hydraulic units, and wherein the piston of one of the hydraulic units is a stepped piston defining a second pressure chamber, thereby providing five pressure chambers. An arrangement of valves provides for selective coupling of hydraulic fluid among the pressure chambers whereby pressure medium is forced from one of the hydraulic units, during an advance of its piton, to the other of the hydraulic units.