GB572222A - Improvements in thrust bearing - Google Patents

Abstract

572,222. Thrust bearings. SVENSKA TURBINFABRIKS AKTIEBOLAGET LJUNGSTROM. April 11, 1944, No. 6666. Convention date, April 30, 1943. [Class 12 (i)] A thrust bearing for a rotary machine part, such as a turbine shaft required to be accurately located, comprises a thrust disc 2 on the machine part (shaft 1) which engages between bearing blocks 4, 5 axially slidable with a play b in an inner casing 6 which is itself axially slidable with a play a in the main casing or housing 8, the inner casing being provided with ports 19, 20 in its end walls, whereby pressure fluid admitted to spaces 15, 16 outside the ends of the inner casing has its escape through such ports throttled by the bearing blocks 4, 5 thereby to set up pressure conditions such that the inner casing is forced in the direction reverse to the shaft thrust to a location such that the shaft is displaced by an amount a - b. If a=b, the shaft has an invariable location ; or a - b may be such as to compensate for thermal expansion. The end faces of the inner casing have projections 13, 14 to limit the movement and so to provide the spaces 15, 16 for the pressure fluid admitted by a pipe 18 and passageway 17. With the shaft 1 subject to a thrust to the left, as shown by arrow 30, the bearing blocks will be moved to the left, thereby to throttle the escape of pressure fluid through port 19 so setting up pressure in the space 15 which forces the inner casing 6 to the right. The pressure of the fluid may be derived from the centrifugal action arising in a radial entry conduit in the shaft and thrust disc, Fig. 2 (not shown), or from the bearing-block film-pressure, Fig. 3 (not shown), in which latter case the bearing blocks move axially with respect to the thrust disc.