GB1109518A - Improvements in or relating to bearing assemblies - Google Patents

Abstract

1,109,518. Bearings; lubricating. WESTLAND AIRCRAFT Ltd. 1 Aug., 1966 [18 Aug., 1965], No. 35515/65. Heading F2A. [Also in Division F1] In a lubricated bearing assembly for a turbounit, a shaft 4, Fig. 1, is mounted in ball bearings 5, 5 which are contained in a carrier 6, supported by walls 7 and 8 of an outer shell 9. The latter contains a lubricant sump 11; a liner 10 which forms a jacket 18 for cooling- fluid; and labyrinth seals 16 and 22 for the carrier 6, the bearings being lubricated by a circulation of lubricant within the carrier 6 and the lubricant being retained therein by pressurized cooling-fluid acting on the outer surfaces of the seals 16 and 22. In operation, pressurized cooling-fluid is passed through an inlet 17 in the shell 9; through the jacket 18 and ports 37; into an annular-space 38 which is formed behind a restrictor-plate 14; through an annular-gap 15, formed between the plate 14 and a rotary-sleeve 32 of the seal 16; into a chamber 26; and out of the unit through ports 27. Some fluid from the inlet of a turbine 2 bleeds through an annular port 33 into a space 20 and then passes through passages 19, into the jacket 18. The pressure differential across the seals 16 and 22 is effected by means of the annular-gap 15 creating a back-pressure in the jacket 18, in the passages 19 and in the space 20, thus providing a pressure on the outer surfaces of the seals; and by means of the inside of the carrier 6 being connected to ambient, via passages 23, 24 and 25 in the shaft 4, the chamber 26 and the ports 27. The bearings 5, 5 are lubricated by mist which is drawn by impellers 36 from wick-loops 31 fed with lubricant by wicks 30 in the sump 11. The lubricant mist passes through the bearings into an annular-space 13, through ports 35, and back to the space between the wick-loops 31. In a modification, the jacket 18 is omitted and the carrier 6 is provided with radial fins 40, Fig. 3, enclosed in a sleeve 41. The fins 40 provide four alternate passages 42 for the cooling-fluid and four alternate passages 43 for the lubricant mist. An axial fan (44), Fig. 2 (not shown), is attached to the shaft 4 and drives cooling-fluid along the passages 42 to the annular-space 38 and then through the gap 15 to the chamber 26 and outlet-ports 27. The lubricant mist drawn from the wick-loops 31 through the bearings by the impellers 36, is delivered through opposite ends of the passages 43 to the radial ports 35 leading back to the interior of the carrier 6.