GB1249651A - Improvements in and relating to hydraulic vane pumps - Google Patents

Abstract

1,249,651. Rotary positive-displacement pumps. ABEX CORP. Oct.14, 1968 [Nov. 27, 1967], No.48630/68. Heading F1F. In a hydraulic-pump of the outwardly-sliding radial-vane type, to sustain contact between a fixed cam-ring 14, Fig. 3, and the vanes 32 of a rotor 28 pressure is exerted on a piston 76 associated with each vane and a portion of the radially-inner-most edge of the latter in register with a bore 77, Fig. 1, in said piston communicating with an annular chamber 71 to which a proportion of the working fluid e.g. oil, is admitted through said bore whenever the respective piston is retracted by the pressure in the end 48 of a slot for the corresponding vane exceeding that in the chamber as a consequence of a groove 67 in the vane coming into register with V-grooves 90, 91 in a checkplate 10 while the vane approaches either of two outlet, or pressure, ports 51, 52. The grooves 90, 91 restrict the flow of fluid therethrough and render the pressure in each space or pocket 40 between the vanes approaching the ports 51, 52 substantial by constant, the grooves 90 being preferably connected hydraulically to outlet passageways 54, 55, Fig. 2, between inlet passageways 47 by flow-restricting passageways 88. The pump shown can be reversed by rotation of the cam ring through 90 degrees relative to the checkplate 10 and a further check-plate 19 defining further inlet passageways 47. If the pump is rendered irreversible the grooves 90, 91 are furnished only on the leading side of each of the outlet ports, the grooves being otherwise provided on either side of each port, as shown. To effect pressure balancing dummy V-grooves (93), Fig. 11 (not shown), may be formed in the check-plate 19, which contains inlet, or suction, ports 45, 46 in axial alignment with similar ports 43. Additional inlet ports 50 are provided in each of the check-plates to permit fluid to enter the ends 48 of the slots when the vanes move outwardly. Recesses 59, 60 in the cam-ring overlap the outlet ports and facilitate reversal of the pump. The trailing side of each vane may contain a groove 82 to effect communication between the end 48 of the respective slot and the associated pocket when the vane projects farthest from the rotor, Fig. 5 (not shown). In a second embodiment, Fig. 14 (not shown), the pistons 76 are dispensed with, pressure being exerted on the radially-innermost edges of the vanes (101) by fluid in annular channels (104) at opposite ends of the rotor intersecting the aforementioned ends of the slots for the vanes. The channels (104) are connected to the grooves 90, 91 and the ports 51, 52 by passages (107) containing non-return valves (108) and orifices equivalent in effect to the passageways 88.