BI-DIRECTIONAL DISC-VALVE MOTOR AND IMPROVED VALVE-SEATING MECHANISM THEREFOR
A rotary fluid pressure device (11 ) has a stationary valve member (17), a rotatable valve member (51 ), and a valve seating mechanism (73). The valve seating mechanism (73) defines an outer balance ring member (75) having a valve-confronting surface (79) in engagement with an opposite surface (81 ) of the rotatable valve member (51 ) and an inner balance ring member (77) having a valve-confronting surface (111 ) in engagement with the opposite surface (81 ) of the rotatable valve member (51 ), with the outer balance ring member (75) and the inner balance ring member (77) being structurally independent from the other. The outer balance ring member (75) and the inner balance ring member (77) define a balance ring passage (71 ) which provides continuous fluid communication between a fluid inlet (53) or a fluid outlet (53) and the valve passages (61 ) in the rotatable valve member (51 ).