GB937826A - Engine driven fan - Google Patents

Abstract

937,826. Lubricating. ROLLS-ROYCE Ltd. April 30, 1962 [May 2, 1961], No. 15926/61. Class 12(3). [Also in Groups XXIV and XXVI] An engine driven fan comprises a gas turbine engine having an engine casing, an outer casing mounted about the engine casing with an annular duct therebetween and fan blades rotatably mounted within the annular duct and arranged to be driven by the gas turbine engine. A lubricating system is provided for lubricating at least part of the gas turbine engine, the system comprising conduit means through which lubricant is circulated, and means for circulating lubricant, at least one portion of the lubricant conduit means comprising hollow guide vanes which extend across the annular duct whereby lubricant is cooled by air passing through the annular duct. The engine shown comprises a compressor 11, combustion equipment 12 and a twostage turbine 13, the turbine and compressor being mounted on a common shaft 14. The engine casing 10 is disposed within an outer casing 42, the two casings affording an annular passage 43 within which are disposed fan blades 44 also inlet guide blades 45 and outlet guide blades 46, the fan blades being secured to a rotary shaft 41 which is drivingly connected to a rotary shaft 40 which is driven from the compressor-turbine shaft 14 through reduction gearing 26. The outlet guide blades 46 are hollow and their outer ends are connected to a pair of semi-circular passages 47, 48 and their inner ends are connected to a pair of semicircular passages 55, 56, lubricating oil flowing, when the engine is operating, radially outwardly through some of the blades 46 from the passage 55 to the passage 47, and radially inwardly through the remaining blades 46 from the passage 56. The engine shown is arranged to be mounted vertically in an aircraft, and a lubricating oil tank 16 is disposed coaxially within the compressor-turbine shaft, an overflow pipe 105 extending through the tank 16. The lubricating oil tank comprises an outer wall having a frusto-conical portion 19, also an inner wall 20, and a bottom wall 101 having apertures 102, and an annular opening 104 between the inner and the bottom walls. A shaft 24 is secured to the radial flange 15 of the shaft 14, and provides an axial extension of the shaft 14. A further shaft 25 is disposed within the shaft 24 and is drivingly connected with the shaft 14, the shaft 25 carrying at its upstream end a pair of gears 29, 29<SP>1</SP> which are in engagement with pinions 33, 33<SP>1</SP> which are rotatably mounted on shafts 32 secured to a fixed carrier 31. The pinions 33, 33<SP>1</SP> engage with internally toothed gears 37, 37<SP>1</SP> which are secured to the shaft 40 by which the shaft 41 and fan blades 44 are driven. A shaft 61 carrying gears 63, 64 is rotatably mounted in the fixed pinion carrier 31 and is driven from the stub shaft 25 by a splined connection 62, the gears 63, 64 meshing with gears 65, 66, the gears 63, 65 forming a main lubricating oil pump, and the gears 64, 66 forming a scavenge oil pump. In operation of the engine, oil will pass from the tank 16 through the passage 21 to the chamber 71 and thence through the duct 70 to the suction side of the pump 63, 65. The oil will discharge through the duct 73 and through the filters 35 and so into the reduction gearing 26, the oil being discharged into the space 28 from which it is collected by scoops 76 of a non-rotating annular member 74. The oil will then pass into the chambers 75 from which it will discharge through apertures 77 into passage 78 and so to the suction side of the scavenge pump 64, 66. The oil will then be discharged into the compartment 86 and will then pass through aperture 90 to the inner semiannular passage 55, the oil then passing through some of the guide blades 46 to the outer semiannular passage 47. The oil in the passage 47 will pass through the passage 53 and a filter 54 to the passage 48, the passages 47 and 48 being separated from each other by walls 51, 52. The oil will pass from the passage 48 through the remaining guide blades 46 to the inner semiannular passage 56 and then through the apertures 81 to the compartments 80. The oil will then pass through the apertures 82 to the chamber 83 and thence via apertures 84, 85 to the interior of the extension shaft 24, and then into the chamber 100 and so back to the tank 16 for further circulation. Oil also passes from the tank 16 through a spring-controlled valve to the rear bearing 117. A normally open pressurizing valve 120 is provided in the flow path between the semi-annular passage 56 and the chamber 100. A non-return valve is disposed in the flow line between the scavenge pump and the semi-annular passage 55 and a pressure relief valve is also provided.