Rotary-motion valve and power-assisted steering system incorporating the valve

A power-assisted steering system for an automotive vehicle, comprising, in combination, first and second members rotatable relative to each other about a common axis of rotation, a self-centering spring element for interconnecting the first and second rotatable members together and for biasing the two members into a predetermined relative angular relative to lack other about said common axis of rotation, a generally cylindrical valve element rotatable with said first rotatable member and having formed in its outer peripheral wall at least two concavities arranged in predetermined angular relationship to each other about said axis, a generally cylindrical valve body rotatable with said second rotatable member about said axis and circumferentially slidable on the outer peripheral surface of the valve element, the valve body having a circumferential groove formed in the inner peripheral wall of the valve body and circumferentially extending over said concavities at least two radial holes arranged in predetermined angular relationship to each other about axis of the rotation of the valve body, and at least two plug members closely fitting in said radial holes, respectively, and projecting into said circumferential groove for dividing the circumferential groove into arcuate groove portions separate from each other across the plug members, the plug members including a first plug member which is solid in its entirety and a second plug member formed with a bore open at one end to the outer peripheral wall of the valve element and at least partially communicable with one of said concavities depending upon the relative angular positions of the valve element and the valve body about the respective axes of rotation of the valve element and body, said concavities in the valve element being substantially in registry with said plug members, respectivey, in radial directions of the valve element and the valve body when the valve element and body are in said predetermined relative angular positions thereof.

A rotary motion fluid flow control valve comprising:

• a non-rotatable valve housing;
• a cylindrical valve body mounted for rotation about its longitudinal axis within said valve housing;
• a cylindrical valve element mounted for rotation about its longitudinal axis within said valve body, said rotational axes being substantially coincident;
• at least two concavities located in the outer surface of said valve element in a predetermined angular relationship relative to said coincident axes;
• a groove extending circumferentially around the inner surface of said valve body, said groove overlying and communicating with each of said concavities;
• at least two radial holes in said valve body in the same predetermined angular relationship relative to said coincident axes, said holes communicating with said groove;
• a first plug member received in and closing one of said holes, and a second plug member received in the other of said holes and having a bore extending therethrough, the innermost ends of said plugs subdividing said groove into groove segments,
• the relative dimensions and shapes of the innermost ends of said plugs and of said concavities being such that the groove segments on opposite sides of said plugs are in communication with each other when said plugs are in radial alignment with said concavities, and the groove segments on opposite sides of said plugs are separated from each other when said plugs are angularly offset relative to said concavities;
• fluid inlet means for connecting said bore to a source of pressurized fluid;
• and,
• fluid outlet means leading from said groove segments and from the concavity associated with said first plug member.