GB758297A - Improvements in or relating to pump control - Google Patents

Abstract

758,297. Fluid-pressure servomotor-control systems. SUNDSTRAND MACHINE TOOL CO. July 28, 1954 [Aug. 10, 1953], No. 22041/54. Class 135. A control mechanism for a variable displacement pump 15 comprises displacement varying means, e.g., the swash plate 80 and means connecting it to an actuating device, e.g., the compound piston 60, having a first element 83 bearing on one side, and a second element 87 bearing on the opposite side, of the displacement varying means, and means, e.g. the two parts 70, 76 of the piston, urging the elements to move in opposite directions to clamp the displacement varying means between them. In the hydraulic transmission from the variable displacement multiplunger pump 15 rotated by gear 25, through multi-plunger motor 16, swash-plate 23 and shaft 24 to gear 26 the pump swash-plate 80 is adjusted by piston 60 under the control of a governor 33 responsive to the speed of gear 26. Aircraft engine lubricating pumps 35, 36 supply oil via passages 39, 42, 43 to a valve chamber located between the pump and motor for maintaining the plungers against the wobblers. The oil then passes to lubricating points 51 via passages 44, 46, 48 and reducing valve 49. Oil is also taken via pipes 53 to supply the governor 33 and provide the control pressure in pipes 31, 32. This pressure forces the two parts 70, 76 towards one another. The part 70 thus pushes the rod 83 into a socket on the wobbler 80 and the rod 87 which is pivoted to the skirt 78 of the part 76 is pulled by that part into a socket on the other side of the wobbler. The space between the elements is open to exhaust via passage 91.