(19)
(11) EP 0 894 982 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
24.05.2000 Bulletin 2000/21

(43) Date of publication A2:
03.02.1999 Bulletin 1999/05

(21) Application number: 98114115.3

(22) Date of filing: 28.07.1998
(51) International Patent Classification (IPC)7: F15B 9/10, F15B 21/04, F15B 11/12
(84) Designated Contracting States:
AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE
Designated Extension States:
AL LT LV MK RO SI

(30) Priority: 29.07.1997 JP 21800397

(71) Applicant: EBARA CORPORATION
Ohta-ku, Tokyo (JP)

(72) Inventors:
  • Ogata, Hiroshi
    Yokohama-shi, Kanagawa-ken (JP)
  • Kimura, Katsumi
    Kawasaki-shi, Kanagawa-ken (JP)
  • Sugiyama, Kazuhiko
    Fujisawa-shi, Kanagawa-ken (JP)
  • Hattori, Kazuo
    Yokosuka-shi, Kanagawa-ken (JP)

(74) Representative: Wagner, Karl H., Dipl.-Ing. et al
WAGNER & GEYER Patentanwälte Gewürzmühlstrasse 5
80538 München
80538 München (DE)

   


(54) Hydraulic servo device


(57) A cylinder houses an angularly movable pilot shaft and a piston axially movably mounted on the pilot shaft. When the pilot shaft is angularly moved, a communication passage defined in an outer circumferential surface of the pilot shaft is brought into communication with an oil supply passage or an oil drain passage for axially moving the piston. The pilot shaft has a pair of communication passages defined in the outer circumferential surface thereof, and the piston has a pair of oil passages defined therein.






Search report