Servostatic bearing system with variable stiffness

Claim 1

A hydraulically sealed, variable stiffness servostatic bearing system comprising, in combination: a. a pair of oppositely acting bearing pads, each said pad being located between and fixed to one of two relatively movable surfaces and having sealed fluid retaining spaces facing said relatively movable surfaces; b. means including a conduit for supplying hydraulic fluid at a given pressure to said fluid retaining spaces, whereby the hydraulic fluid within said spaces supports a substantial part of an external load imposed upon said relatively movable surfaces; c. means for sensing the spacing between said relatively movable surfaces including: i. a valve connected to the fluid supply conduit in parallel with a first pad of a pair of oppositely acting pads, ii. an external fluid flow restrictor connected to the fluid supply conduit in parallel with the second pad of a pair of oppositely acting pads, iii. a plunger for sensing the bearing surface spacing across said first pad, iv. said plunger being supported within a valve housing attached to one of the relatively movable surfaces and in contact with a reference surface reflecting the position of the other movable surface, v. said plunger being adapted to control the position of the valve which in turn controls the hydraulic fluid supply to said pads according to the spacing between said surfaces, whereby when the sensed spacing is below a predetermined value the valve closes, directing more hydraulic fluid to the pad located between the inadequately spaced surfaces, and when the spacing exceeds said predetermined value the valve opens, decreasing the fluid supply to the pad located between the excessively spaced surfaces; d. fluid distribution valve means interposed in said supply conduit between the hydraulic fluid supply means and the pads and spacing sensing means, for distributing hydraulic fluid flow from the supply means to the respective pads and sensing means, including: i. a double acting diaphragm creating two flow restrictions within a valve housing, ii. said flow restrictions communicating with the fluid retaining spaces of each of an oppositely acting pair of bearing pads, iii. the diaphragm being adapted to cause increased flow to the fluid retaining spaces of the pad exhibiting the higher pressure of the oppositely acting pair of bearing pads, while simultaneously restricting flow to the fluid retaining spaces of the pad exhibiting the lower pressure; and e. pressure regulating means to control the pressure of the hydraulic fluid supply entering the fluid distribution valve means, whereby adjustments in said pressure cause changes in the stiffness of said bearing system.