Hydraulic control valves
OwnerWilliam H. S. Rampeninventor
Life of this patent
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Abstract
A hydraulic valve has a tapered plug rotatable in a complementary tapered bore in a stationary housing so that the axial position of the plug controls the magnitude of a leakage path between the two parts. The magnitude of the leakage path is sensed and used to control the axial position of the plug in a negative feedback arrangement so that the valve plug floats on a film of escaping hydraulic fluid and can be readily rotated by a low power actuator. Ports in the stationary member and passages in the plug are arranged so that both static and preferably also dynamic and hydraulic forces acting on the plugs are balanced. The valve is contained in a closed housing, preferably together with the actuator.
Claims16
In a balanced hydraulic valve structure of the type comprising a stationary member and a rotatable plug received in a bore defined in the stationary member, wherein valving is achieved by establishing selective communication between valve ports opening into the bore defined by the stationary member through cavities formed in the plug, the ports and cavities being arranged so that there is substantial cancellation of radially acting hydrostatic forces acting on the plug, and the plug and the bore being provided with complementary tapers;
- the improvement wherein a variable leakage path is defined between the plug and the bore of a magnitude determined by their relative axial position;
- linear actuator means is provided to sustain unbalanced axial hydrostatic forces acting on the tapered plug;
- and means are provided to sense movement of the plug and to establish a negative feedback loop to said linear actuator means whereby to cause the latter to oppose movements of the plug tending to alter the leakage path from a nominal value corresponding to an equilibrium position of the plug relative to the bore.
Dependencies are inferred from the claim text.