Bearings for continuous casting roller aprons

Claim 1

In a roller apron for supporting and guiding a metal strand formed in a continuous casting mold through a cooling system such as a water spray or the like, said roller apron having spaced apart rails with elongated rollers extending between the rails and with the rollers each formed of a center shaft and with means fixedly mounting the shaft upon the rails, and a surrounding cylindrically shaped roller sleeve rotatably fitted around the shaft and having its inner circular wall spaced from the outer surface of the shaft, an improved bearing construction comprising: a journal type bearing arranged between the shaft and roller sleeve and formed of an elongated, thin-wall, generally cylindrically shaped bearing sleeve surrounding the shaft and said bearing sleeve having an axial length, the entire outer surface along the axial length of said bearing sleeve being tightly in surface to surface contact with the inner wall of the roller sleeve so as to form a non-slip, frictional engagement with the roller sleeve and roughly one-half of the axial length of the inner surface of said bearing sleeve forming a rotatable contact with the shaft; an annular, cylindrically shaped recess of substantial width formed along roughly one-half of the axial length of said bearing sleeve in the inner surface of the bearing sleeve and a thin-wall, cylindrically shaped liner bushing being tightly and non-rotatably fitted within and along substantially the full width of the recess, and the inner surface wall of the bushing rotatably engaging the shaft and forming a part of the shaft engaging wall surface of the bearing; and said bearing sleeve being formed of a bronze-like bearing type material of relatively substantial compressive strength, and with the liner bushing being formed of a lower coefficient of friction, but lower compressive strength material; said sleeve and said liner bushing together providing a reduced friction surface for said roller shaft than would be provided by a bronze-like sleeve, and yet providing greater resistance to compression forces transmitted by said shaft, in response to the temperature and ferrostatic pressures of said strand and said cooling system, than would be provided by a lower compressive strength material bushing.