| 摘要 |
<p>A rotary fluid pressure device (11) is disclosed of the type including an internal gear set (17) defining expanding and contracting volume chambers (29). The device further includes a stationary valve member (19) and a rotary valve member (55) having engaging valve surfaces (71,73). A valve seating mechanism (75) includes an annular balancing ring member (77) having a valve-confronting surface (78) engaging an opposite surface (68) of the rotary valve. In accordance with the present invention, it has now been recognized that stalling of the device is normally caused by separation of the balancing ring from the rotary valve, rather than lift-off of the rotary valve from the stationary valve. There is disclosed several ways of modifying the valve seating mechanism to prevent substantial flow of leakage fluid through the balancing passages (107) which, in turn, causes a substantial pressure differential across the balancing ring, and separation of the balancing ring from the rotary valve. In one embodiment, the balancing ring includes an annular groove (105) which is sufficient to communicate substantially all leakage flow to a drain passage (66) defined by the rotary valve to prevent a build-up of pressure acting on the valve-confronting surface (78).</p> |
