Hydraulic actuator and method for operating
AssigneeAirbus Operations GmbH
InventorTanno Zantz
Life of this patent
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Abstract
A hydraulic actuator comprising a housing, a piston, first to third pressure chambers, and a plurality of arrangements of piezoelectric elements arranged inside one of the plurality of chambers. A computer implemented internal brake for selectively switching between a braking mode and a non-braking mode of the piston comprises the third chamber, and fluid connections between the first to third chambers with flow control elements.
Claims17
A hydraulic actuator comprising:
- a housing surrounding a cavity,
- a piston arranged on a piston rod,
- a plurality of pressure chambers, and
- a plurality of arrangements of piezoelectric elements, each of the arrangements arranged adjacent a chamber from the plurality of chambers and configured to selectively contract or expand in order to change a volume of the chamber bordered by the piezoelectric elements of the arrangement;
- and
- a braking means configured for a selectively switching between a braking mode and a non-braking mode, wherein in the braking mode the braking means brakes movement of the piston and in the non-braking mode the braking means does not brake movement of the piston,
- wherein the plurality of pressure chambers includes a first chamber and a second chamber separated by the piston that is movable along an actuation direction,
- wherein the plurality of arrangements of piezoelectric elements includes a first arrangement of piezoelectric elements arranged adjacent the first chamber and configured to change a volume of the first chamber occupied by the piezoelectric elements of the first arrangement, and
- wherein the plurality of arrangements of piezoelectric elements includes a second arrangement of piezoelectric elements,
- wherein the plurality of pressure chambers includes a third chamber,
- wherein the braking means comprises the third chamber, a first fluid connection with a first flow control means and a second fluid connection with a second flow control means;
- wherein the first fluid connection connects the third chamber and the first chamber and the first flow control means is configured to selectively vary a flow of a hydraulic fluid through the first fluid connection, and
- wherein the second fluid connection connects the third chamber and the second chamber and the second flow control means is configured to selectively vary a flow of hydraulic fluid through the second fluid connection,
- wherein the second arrangement of piezoelectric elements is arranged adjacent the third chamber and is configured to change a volume of the third chamber.
A method for operating a hydraulic actuator comprising a housing surrounding a cavity, a piston arranged on a piston rod, a plurality of pressure chambers, and a plurality of arrangements of piezoelectric elements, each of the arrangements arranged adjacent a chamber from the plurality of chambers and configured to selectively contract or expand in order to change a volume of said chamber, and a braking means configured for a selectively switching between a braking mode and a non-braking mode, wherein in the braking mode the braking means brakes movement of the piston and in the non-braking mode does not brake movement of the piston, wherein the plurality of pressure chambers includes a first chamber and a second chamber separated by the piston that is movable along an actuation direction, wherein the plurality of arrangements of piezoelectric elements includes a first arrangement of piezoelectric elements arranged adjacent the first chamber and configured to change the volume of the first chamber, and wherein the plurality of arrangements of piezoelectric elements includes a second arrangement of piezoelectric elements, wherein the braking means comprises a third chamber, a first fluid connection with a first flow control means and a second fluid connection with a second flow control means, wherein the first fluid connection connects the third chamber and the first chamber and the first flow control means is configured to selectively vary a flow of a hydraulic fluid through the first fluid connection, and wherein the second fluid connection connects the third chamber and the second chamber and the second flow control means is configured to selectively vary the flow of hydraulic fluid through the second fluid connection, wherein the second arrangement of piezoelectric elements s arranged adjacent the third chamber and is configured to change the volume of the third chamber occu, the method comprising the following sequence of steps:
- a) while the first flow control means is closed, opening the second flow control means, expanding the first arrangement of piezoelectric elements and contracting the second arrangement of piezoelectric elements so that the piston moves in a direction towards the second chamber, the volume of the second chamber is decreased and hydraulic fluid flows from the second chamber via the second fluid connection to the third chamber;
- b) closing the second flow control means;
- c) opening the first flow control means, contracting the first arrangement of piezoelectric elements, and expanding the second arrangement of piezoelectric elements so that hydraulic fluid flows from the third chamber via the first fluid connection to the first chamber and the movement of the piston is braked;
- d) closing the first flow control means.
Dependencies are inferred from the claim text.