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AssigneesEbara Research Co., Ltd., Eizo Urata
InventorsEizo Urata, Shinpei Miyakawa
Life of this patent
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Abstract
An improved hydraulic servo-valve including a spool (10, 10R, 10L) adapted to slidably move in a valve body (1) to change the direction of flow of a working liquid and vary a flow rate of the working liquid, nozzle back-pressure chambers (18, 18R, 18L) to which a pilot pressure is applied for displacing the spool (10, 10R, 10L), and a flapper mechanism comprising nozzles (19, 19R, 19L) and flappers (20, 20R, 20L) is disclosed. Static pressure bearings (14R, 14L, 141R, 141L, 142R, 142L) are formed at opposite ends of the spool (10, 10R, 10L). In addition, the hydraulic servo-valve is formed with passages extend from a pump port (P) to the nozzle back-pressure chambers (18, 18R, 18L) via the static pressure bearings (14R, 14L, 141R, 141L, 142R, 142L).
Claims7
A hydraulic servo-valve comprising:
- a spool adapted to slidably move in a valve body to change a direction of flowing of a working liquid and vary a flow rate of said working liquid;
- nozzle back-pressure chambers to which a pilot pressure is applied to displace said spool;
- a flapper mechanism including a nozzle and a flapper;
- static pressure bearings formed at opposite ends of said spool, each of said static pressure bearings including a plurality of orifices and a pocket;
- and
- a passage is formed inside said spool and connected to said static pressure bearings and to a pump port so as to allow the working liquid to flow from said pump port through said orifices and pocket of said static pressure bearing to said nozzle back-pressure chamber.
Dependencies are inferred from the claim text.