초록 ▼

Actuators and corresponding methods and systems for controlling such actuators offer efficient, fast, flexible control with large forces. In an exemplary embodiment, an fluid actuator includes a housing having first and second fluid ports, an actuation cylinder in the housing defining a longitudinal

Actuators and corresponding methods and systems for controlling such actuators offer efficient, fast, flexible control with large forces. In an exemplary embodiment, an fluid actuator includes a housing having first and second fluid ports, an actuation cylinder in the housing defining a longitudinal axis and having first and second ends in first and second directions, an actuation piston in the cylinder with first and second surfaces moveable along the longitudinal axis, a spring subsystem biasing the actuation piston to a neutral position, a first fluid space defined by the first end of the actuation cylinder and the first surface of the actuation piston, and a second fluid space defined by the second end of the actuation cylinder and the second surface of the actuation piston. A first flow mechanism controls fluid communication between the first fluid space and the first port, whereas a second flow mechanism controls fluid communication between the second fluid space and the second port. The first and second flow mechanisms are substantially restricted through two integrated snubbing mechanisms when the actuation piston approaches the first and second direction ends of its travel, respectively. In addition to a differential fluid force on the actuation piston, there is a centering or returning spring force available to help open the engine valve against the high cross-over passage pressure, without the need for the fluid actuation system to be bulky and consume too much energy.

대표청구항 ▼

I claim: 1. A fluid actuator, comprising a housing having first and second fluid ports; an actuation cylinder in the housing defining a longitudinal axis and having first and second ends in first and second directions; an actuation piston in the cylinder with first and second surfaces moveable alon

I claim: 1. A fluid actuator, comprising a housing having first and second fluid ports; an actuation cylinder in the housing defining a longitudinal axis and having first and second ends in first and second directions; an actuation piston in the cylinder with first and second surfaces moveable along the longitudinal axis; a spring subsystem biasing the actuation piston to a neutral position; a second piston rod operably connected with the actuation piston and the spring subsystem; a first fluid space defined by the first end of the actuation cylinder and the first surface of the actuation piston; a second fluid space defined by the second end of the actuation cylinder and the second surface of the actuation piston, and separated, within the actuation cylinder, from the first fluid space by the actuation piston in the entire travel range of the actuation piston; a first flow mechanism controlling fluid communication between the first fluid space and the first port; and a second flow mechanism controlling fluid communication between the second fluid space and the second port. 2. The fluid actuator of claim 1, further comprising a first piston rod, operably connected with the first surface of the actuation piston. 3. The actuator of claim 2, wherein the first and second piston rods having two different predefined diameters, whereby resulting in appreciably different pressure areas on two actuation piston surfaces and thus appreciably different net fluid forces in the first and second directions under an identical pressure differential. 4. The fluid actuator of claim 1, further comprising at least one snubbing mechanism, whereby reducing the travel velocity of the actuation piston as it approaches at least one of its end positions. 5. The fluid actuator of claim 4, further comprising at least one check valve providing a one-way flow bypass around the at-least-one snubbing mechanism. 6. The fluid actuator of claim 5, wherein the at-least-one check valve is of the reed valve type. 7. The actuator of claim 1, wherein the spring subsystem further comprising at least one first actuation spring and at least one second actuation spring. 8. The actuator of claim 1, wherein the first and second ports being supplied by a first actuation 3-way valve and a second actuation 3-way valve, respectively. 9. The actuator of claim 1, wherein both the first and second ports being supplied by an actuation switch valve. 10. The actuator of claim 1, wherein both the first and second ports being supplied by an actuation proportional valve. 11. The actuator of claim 1, further comprising an engine valve operably connected with the second piston rod. 12. The actuator of claim 1, further comprising a spring controller, whereby controlling the state of compression of the spring subsystem. 13. The actuator of claim 1, wherein at least one of the first and second flow mechanisms including an annular space between a bore and a piston rod neck. 14. The actuator of claim 1, wherein at least one of the first and second flow mechanisms including an annular space between a bore undercut and a piston rod. 15. The actuator of claim 1, wherein at least one of the first and second flow mechanisms including an actuation-cylinder undercut.