GB942842A - Gas turbine engine - Google Patents

Abstract

942,842. Lubricating. ROLLS-ROYCE Ltd. May 4, 1962 [May 10, 1961], No. 17100/61. Heading F2A. [Also in Division F1] A gas turbine engine has a shaft which carries the compressor and the turbine of the engine, a bearing in which the shaft is rotatably mounted, and means for supplying lubricant to the bearing. A bearing housing chamber in which the bearing is housed is provided also a sump chamber to which may drain lubricant which has passed through the bearing, there being also at least one ejector pump for pumping lubricant out of the sump chamber and for maintaining a low pressure within the bearing housing chamber. By the term "ejector pump " is meant a known kind of pump which has no moving parts but which aspirates the " pumped " medium at the throat of a Venturi through which a fluid such as compressed air flows. The invention is described with reference to a gas turbine engine of the vertical lift type comprising an air compressor 13 and a turbine 15 mounted on a common shaft 17, the upstream end of which is supported in a bearing 19. The upstream end of the shaft 17 is formed with an extension 18 on which the inner race 21 of the bearing 19 is mounted, the outer race 20 of the bearing being in splined engagement with an inner housing member 22 which is secured within an outer housing member 23, the member 23 being supported from the outer casing 11 by the inlet guide vanes 12. The upper face of the outer race 20 is engaged by a ring member 24 which is also in splined engagement with the housing member 22 and is acted on by springs 25. The action of the springs 25 tends to counteract the thrust exerted on the shaft 17 by the compressor. An annular member 27 is secured to the shaft extension 18 adjacent the lower face of the inner race 21 of the bearing, the member 27 having an axial portion 30 and a radially-extending flange 31. A flange member 32 secured to the outer housing member 23 has an axially-extending flange 34 to form a seal with the axially-extending portion 30. The flange 31 forms with adjacent parts a sump chamber 35 and a chamber 36. The chambers 35, 36 are connected respectively by lines 37, 38 which extend through a hollow guide vane 12 to ejector pumps 39 disposed externally of the casing 11, the pumps acting to pump oil from the sump chamber 35 and air from the chamber 36, thereby maintaining the pressure within the chamber 36 lower than the pressure within the working fluid duct of the engine. A line 40 also passes through the hollow guide vane 12 and provides a means by which a single shot of oil may be introduced to the upstream side of the member 24, the oil passing through orifices 41 to the bearing 19 and thence to the sump chamber 35. A sleeve 42 is splined internally within the shaft extension 18 and the flange 44 of a quill shaft 43 is splined within the sleeve, the quill shaft in turn being splined to the drive shaft 47 of a fuel pump 46. A sump 51 is formed in the wall member 52 which is secured to the shaft extension 18, lubricating oil supplied to the fuel pump draining back to the sump 51 and being centrifuged through ports 50 to the sump chamber 35.