Rotary hydraulic machine

A rotary fluid machine comprising an operating part (49, 57) housed within a casing (11), and a hermetically sealed lubrication chamber (102) defined within the casing (11), the operating part (49, 57) converting into mechanical energy the thermal energy and the pressure energy of a working medium introduced into an operating chamber (82, 84) sealed by a seal (47, 48, 78, 79), and oil for lubricating at least the operating part (49, 57) residing in the lubrication chamber (102);

• wherein a breather chamber (101, 103) is provided in an upper part of the lubrication chamber (102), a working medium discharge chamber (90) into which the working medium is discharged from the operating chamber (82, 84) is made to communicate with the breather chamber (101, 103) via a breather passage (B1 to B4), a mixture of oil and the working medium that has leaked from the operating chamber (82, 84) into the lubrication chamber (102) through the seal (47, 48, 78, 79) is separated in the breather chamber (101, 103), the separated oil is returned from the breather chamber (101, 103) to the lubrication chamber (102), and the separated working medium is returned from the breather chamber (101, 103) to the working medium discharge chamber (90) via the breather passage (B1 to B4) corresponding to the amount of working medium that has leaked.