Rotary machine

摘要

A rotary hydraulic machine (10) for incorporation in a drill string (92) of a well formation (86). The machine (10) is particularly adapted to act as a motor and includes an outer housing (11) of a generally cylindrical configuration having a radial inner surface (12). Rotatably mounted within the housing (11) is a shaft assembly (13) including a shaft (14) upon which a stator (15) is mounted. The stator (15) includes a plurality of lobes (16) which have a maximum radius approximately equal to the radius of the surface (12). A plurality of gates (35) are radially movably mounted in the housing (11) and engage the stator (15). The shaft (14) is hollow to provide for the delivery and the removal of hydraulic fluid to the working chambers (45 and 46) of the machine (10).