Fluid flow machine

摘要

931,904. Bearings. ROLLS-ROYCE Ltd. March 30, 1962 [April 5, 1961], No. 12253/61. Class 12 (1). [Also in Group XXVI] A fluid-flow machine such as a gas-turbine engine, comprises rotatable shafting, one or more bladed members being mounted on the shafting, the members being subject, in operation, to thrust from the working fluid flowing through the machine. A thrust bearing is provided for the shafting, the thrust bearing being arranged to be subjected to the thrust or net thrust from the bladed member or members, there being also provided resilient means for urging the thrust bearing in a direction to oppose the thrust or net thrust, also means for applying to the thrust bearing one or more fluid pressures whose effect or net effect is also to oppose the thrust or net thrust. The invention is described with reference to a gas-turbine engine which comprises an auxiliary compressor 18 which may supply air under pressure for operation of blown flaps on an aircraft in which the engine is installed. The engine comprises a main compressor 15 and a turbine 16 mounted on a shaft 12 which is supported in bearings 13, 14. The engine also comprises a separate power turbine 26 the shaft 22 of which is mounted in bearings 23, 24, the shaft 22 being in splined connection with a shaft 17 to which the rotor 18 of the auxiliary compressor is secured. The shaft 17 is supported in bearings 19, 21. The intakes 28, 29 of the two compressors are disposed adjacently, the air streams being guided from the annular opening 27 by a baffle 31. The bearing 23 is arranged in accordance with the invention and as shown in Fig. 2, comprises an outer race 231 which is supported within a resilient diaphragm 33. The outer periphery of the diaphragm is secured between a ring member 34 and an annular flange 35 of a radially flexible ring 36, the ring 36 being secured to the radially inner ends of stator blades 37. Annular casings 40, 41 are secured at either side of the diaphragm so as to afford chambers 43, 44 at the upstream and downstream sides respectively of the diaphragm, the diaphragm 33, ring 34, flange 35 and casings 40, 41 being secured together by bolts 42, Fig. 3. Holes 45 are formed at the periphery of the diaphragm 33 between the bolt-receiving holes and holes 46, 47 and 48 are formed in the casing 40, flange 35 and ring 34 respectively (see Fig. 4), so that pressure fluid at the upstream side of the diaphragm assembly may pass to the chamber 44 at the downstream side of the diaphragm. Similarly, holes 50, 51 and 52 are formed in the casing 41, ring 34 and flange 35 respectively (see Fig. 5), whereby pressure fluid. at the downstream side of the diaphragm assembly may pass to the chamber 43 at the upstream side of the diaphragm. Since the fluid pressure at the upstream side of the diaphragm assembly is greater than that at the downstream side, the resulting pressure difference on the diaphragm itself will act in the upstream direction and so tond to balance the downstream thrust on the turbine rotor 26.