GB1341414A - Variable displacement vane-type rotary pumps or motors - Google Patents

Abstract

1341414 Rotary positive-displacement pumps and motors CHANDLER EVANS Inc 19 April 1971 [14 April 1970] 26924/71 Heading F1F A pump or motor, e.g. a variable output fuelpump, comprises a rotor 18 carrying outwardlysliding vanes 22 that engage with a cam track defined by a pair of elements 26, 28, which can be moved radially relative to each other by partial rotation of a ring 32 in response to pressure applied to pistons 34, 36. The elements have mutually engaging tongues and grooves, Figs.3 and 4 (not shown), and are prevented from rotating by a frame 30 and pistons 43, 45. An inlet conduit 16 communicates with a pair of inlet ports in each element, Figs.3 and 5 (not shown), by way of a cavity 14. A pair of outlet ports in each element is connected to a discharge conduit 14b by way of a passage 26f, or 28f, and the interior of a wash-flow filter 148. A pressureloaded piston 52 urges an end plate 48 and the rotor towards a further end plate 46. Each of the end plates has lugs 136, 138 engaging with holes in the frame 30 to prevent rotation. Pressure is communicated to the inner ends of the vanes from the passages 26f, 28f through apertures 122, 124 in register with said passages, and recesses 126, 128 in each end plate. Recesses 132, 134 facilitate escape of leakage fluid and limit the outward thrust on each plate. The profile of the cam track is described in detail with reference to Fig.1A (not shown). To actuate the pistons 34, 36 a pressure differential is applied through conduits 226, 228 to bellows 216 and thereby moves a value spool 188, 190, 192, 194 accordingly to apply inlet and discharge pressures to opposite sides of the pistons, the discharge pressure being transmitted through the filter. The piston 52 is subjected to discharge pressure through conduits 158, 160 and an orifice 163 adjacent a pressure-relief valve 144. Bearings for the rotor may be lubricated through a conduit 230.