Control means for a hydraulic servomotor
AssigneeDanfoss A/S
InventorsFlemming Thomsen, Harry S. Nissen, Kjeld Ravn, Carl C. Dixen
Life of this patent
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Abstract
A control system for a two way acting hydraulic servomotor wherein the servomotor is connected in the diagonal of a bridge circuit that includes four magnetic valves with a pair of the valves being normally open in a non-energized condition being connected to the one end of the servomotor and to the container and a second pair of the valves being normally closed in a deenergized condition being connected to the opposite end of the servomotor and to a pressure source. Circuitry provides pulse trains that are modulatable to control the operation of the magnetic valves and thereby the application of pressurized fluid to the opposite ends of the servomotor.
Claims14
Control means for a hydraulic servomotor having a slide member and means resiliently retaining the slide member in a neutral position while permitting movement from the neutral position to a first operative position by application of fluid pressure to a first fluid chamber of the servomotor to extend into the servomotor second fluid chamber, comprising a source of pressurized fluid, a container, a first magnetic valve fluidly connected between the second chamber and container, a second magnetic valve fluidly connected between the source and the first chamber for controlling the application pressurized fluid from the source to the first chamber, the first valve being normally open in a de-energized condition, the second valve being normal closed in a de-energized condition, and energizing means for generating a first and a second train of control pulses and applying the pulses to the valves to open the valves for a timed overlap, the energizing means being connected to the first valve for applying the first train of pulses thereto to close the first valve and to the second valve for applying the second train of pulses thereto to control the opening of the second valve.
Dependencies are inferred from the claim text.