Patent ID: 7950672

Claim:
A magnetic fluid sealing device having a biaxial co-axial rotation structure, comprising: a case having a shaft bearing formed therein and an outer bearing provided on the inner peripheral surface of the bearing hole; a cylindrical outer rotational shaft supported freely rotatably by the outer bearing in the bearing hole; an inner bearing provided on the inner peripheral surface of a hollow portion of the outer rotational shaft; an inner rotational shaft supported freely rotatably by the inner bearing in the hollow portion of the outer rotational shaft, a groove formed in the outer rotational shaft extending radially into the outer rotational shaft; a magnet received in the groove extending below a surface of the outer rotational shaft and rotating with the outer rotational shaft; a first minute gap between the case and the outer rotational shaft, said first minute gap being filled with magnetic fluid; and a second minute gap between the outer rotational shaft and the inner rotational shaft, said second minute gap being filled with magnetic fluid, wherein an outer magnetic circuit passing through the case and an inner magnetic circuit passing through the inner rotational shaft are formed by magnetic force occurring from the magnet.