Patent ID: 7802920

Claim:
A static-pressure gas bearing mechanism comprising: a rod driven in an axial direction inside a bearing housing, said rod performing an operation at a forward end thereof; and first and second static-pressure gas bearings disposed, respectively, at first and second positions in the axial direction of the rod, said first and second static-pressure gas bearings for supporting the rod in a non-contact manner by an air layer, wherein the first static-pressure gas bearing is fixedly supported by the bearing housing and the second static-pressure gas bearing is movably supported by a movable support mechanism of the bearing housing, the movable support mechanism comprises an actuator to displace a shaft center of the second static-pressure gas bearing relative to the first static-pressure gas bearing, in response to a load on the rod, and a control device for driving the actuator during said displacement in accordance with said load, said displacement of the shaft center of the second static-pressure gas bearing reducing contact between a part of the rod and the first and second static-pressure gas bearings caused by said load, the rod is a working rod arranged horizontally and having a working instrument at the forward end of the rod, and the load on the rod is a moment acting on the rod caused by both the weight of a portion of the rod protruding from the first static-pressure gas bearing of the rod and an external force acting on the working instrument is the load on the rod, and the load on the rod is calculated by the control device according to a driving program of the rod, and the actuator is driven based on the calculation result.