GB908687A - Improvements in and relating to hydraulic machines operable as rotary pumps or motors - Google Patents

Abstract

908,687. Gear pumps and motors. BOSCH G.mb.H., ROBERT. Feb. 28, 1961 [March 1, 1960]; No. 7282/61. Class 110 (2). A gear pump or motor comprises a housing 1, Fig. 1, having a figure " 8 " shaped cavity 2 closed by a cover-plate 3 and housing meshing gear-wheels 4, 5 carried on shafts 6, 7. The shafts are journalled in bearing members 8, 9, each of which is formed with slots 17, 18, Fig. 2, and grooves 21, 22 to provide resilient end sections 19, 20 enclosing the shafts. Recesses 13 bounded by sealing rings 12 formed on the outer end faces of the members 8, 9 communicate through a passage 14 with the pressure side of the motor or pump to hydraulically urge the members 8, 9 into sealing engagement with the adjacent side faces of the gear-wheels. Radially effective pressure zones 23, 24 bounded by seal rings 25, 26 located between each bearing member and the housing communicate with the passage 14 through respective ducts 29, 30, a chamber 28 closed by a piston 31 and a branch passage 27. The pressure zones 23, 24 also communicate with recesses 34, 35 in the bores of the bearing members through restricted ducts 32, 33. The pressure zones are large enough to ensure that the resilient end sections 19, 20 are pressed by hydraulic pressure against the shafts and the gear-wheels against the housing in the vicinity of the high pressure chamber to form an effective seal. Pressure oil entering the recesses 34, 35 hydraulically absorbs the bearing loads and lubricates the bushes. Each piston 31 urges its related bearing member towards the pressure chamber.