Abstract

A hydraulic device includes an internally toothed stator formed by a one-piece homogeneous body having a continuous inner wall defining a series of circumferentially spaced arcuate recesses each of which is dimensioned to receive a radially and circumferentially shiftable roller vane. The continuous inner wall further includes a series of radially oriented notches which are disposed between the arcuate recesses and which serve to make portions of the stator wall defining the arcuate recesses resiliently deflectable as a function of the forces applied to the rollers vanes. Further, the notches direct fluid flow to and from expanding and contracting fluid pockets defined between the roller vanes and the teeth of an externally toothed rotor located within the stator.