GB764860A - Bearing assemblies and the lubrication thereof - Google Patents

Abstract

764,860. Stuffing-box substitutes. NAPIER & SON, Ltd., D. Oct. 13, 1954 [Oct. 26, 1953], No. 29590/53. Class 122 (5). [Also in Group XXXIV] A bearing assembly comprises at least one bearing of the ball or roller type, sealing means of the labyrinth type between the inner and outer members on each side of the bearing forming an annular chamber, means comprising a metering orifice for delivering lubricating oil at a controlled rate through a nozzle on to the bearing, and means for continuously withdrawing fluid from the chamber at a volumetric rate higher than that at which oil is delivered to the chamber, and an interconnecting passage or the equivalent between the spaces on the sides of the sealing means remote from the bearing, so as to tend to equalize the pressures in these two spaces, thereby tending to maintain a continuous flow of fluid inwards past both sealing means towards the bearing. The invention is described as applied to a bearing supporting a common turbine and compressor shaft in an aircraft gas turbine propulsion unit. A sealing disc 15 mounted on the compressor shaft 11 is provided with flanges 16, 18 which cooperate with parts of the casing 20 to constitute labyrinth type seals preventing compressed air from passing inwardly towards a housing 21 for a roller bearing 36. A cylindrical liner 22 secured within the housing is provided at one end with a flange 23 and at the other end with a clamping ring 24 for holding in place labyrinth sealing members which comprise a sealing member 26 co-operating with a sealing member 28 on the shaft 11, sealing members 29, 31, co-operating with a sealing member 30 on the shaft 11, and a sealing member 33 co-operating with a sealing member 34 on the shaft 11. Chambers 47, 48 are interconnected to be at the same pressure. Oil is supplied to the bearing from a tank by a displacement pump 65 in parallel with a pressure relief valve 66, the oil passing through passages 64, 63, 62, 60 and through inclined nozzles of small cross-sectional area. The oil is withdrawn through passages 51, 52, 53 by a positive displacement vane type pump 54 associated with an air separation chamber. The volumetric rate of withdrawal of fluid by the pump 54 is considerably in excess of the volumetric rate at which oil is supplied through the nozzle passages 60, so that there is a continuous flow of air inwards past the labyrinth sealing means towards the bearing to prevent loss of oil.