(19)
(11) EP 0 263 558 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
03.01.1990 Bulletin 1990/01

(43) Date of publication A2:
13.04.1988 Bulletin 1988/15

(21) Application number: 87201880.9

(22) Date of filing: 01.10.1987
(51) International Patent Classification (IPC)4: F04B 49/10
(84) Designated Contracting States:
AT BE CH DE ES FR GB IT LI NL

(30) Priority: 09.10.1986 IT 2195186

(71) Applicant: RIVA CALZONI S.p.A.
I-20144 Milano (IT)

(72) Inventor:
  • De Vietro, Ivano
    S. Lazzaro Di Savena Bologna (IT)

(74) Representative: Raimondi, Alfredo, Dott. Ing. Prof. et al
Studio Tecnico Consulenza Brevetti Piazzale Cadorna 15
20123 Milano
20123 Milano (IT)


(56) References cited: : 
   
       


    (54) Hydraulic piston motor having means for measuring the speed of rotation


    (57) The hydraulic piston motor comprising means for measuring the speed of rotation according to the invention comprises a rotating hydraulic distributor adapted to supply hydraulic pressure fluid in cycles to the pistons driving the motor, and having a revolving internal member (15) rotating integrally with the drive shaft (16) and comprising ducts (17) for distributing hydraulic fluid, a sensor (8) being present in a fixed position on the hydraulic distributor and facing the revolving member (15), the outer surface of which is formed with discontinuities (12) detectable by the sensor (8) which, corresponding to the periodic detection of the aforementioned discontinuties during the rotation of the revolving member (15), generates a signal at a frequency proportional to the speed of rotation of the member (15), means being present for protecting the sensors from the pressure of the hydraulic fluid in the fixed outer casing of the distributor.







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