Patent GB-1142961-A (GB)
Title: Rotary fluid pump or motor of axially sliding vane type
IPC: F04C14/02
Filed: 1966-02-21
Abstract: 1,142,961. Hydrostatic transmissions. A. F. ECKFORD. 21 Feb., 1966, No. 7426/66. Heading F2C. [Also in Division F1] A torque converter to give stepless variation of speed, comprises a casing 1, Fig. 14, housing a pump and a motor of identical construction of the axially-sliding vane type (see Division F1). Pump and motor rotors 2, 3 closely fitting the casing are mounted for independent rotation in either direction on shafts 4, 5 and each have a plurality of radial slots 9 slidably mounting axially-movable vanes 10 whose ends abut endfaced fixed cams 11, 12, 13, with cam 12 being common to both rotors, and axially adjustable cams 17, 18, 19, with cam 18 being common to both rotors. Cams 17, 18, 19 are disposed diametrically opposite cams 11, 12, 13 respectively and are interconnected for sliding adjustment by means of a bar 20 and spigots 17e, 18e, 19e projecting through slots 17f, 18f, 19f in the casing 1. The bar 20 is conveniently broken at 23 to permit the insertion of shims and the relative adjustment of cam 19 with respect to cams 17, 18. The bar 20 may be slidably adjusted by means of hydraulic rams, pneumatic pistons, levers, magnetic devices, cams, screw threads or other convenient means. Helicoidal cam surfaces 17a, 18a, 18b, 19a are concentric with an overlap helicoidal cam surfaces to 11c, 12c, 12d, 13c respectively to leave part annular gaps 24, Fig. 15, constituting fluid passages between the pump and motor. On displacement of cam 18 so that surface 18a causes axial movement of the vanes rotating between flat sealing surfaces 12c, 18a, pumping is caused on rotation of rotor 2. The fluid passes into and out of the pumping chamber nearest to cams 18, 12, with the direction of flow being dependent upon direction of rotation of rotor 2 and the relative distance of cam surfaces 12c, 18a from the face of the rotor 2. The displaced fluid passes through the gaps 24 to exert pressure on the vanes 10 of rotor 3 with the speed of revolution depending upon axial displacement of vanes 10 of rotor 3 compared with the axial displacement of vanes 10 of rotor 2. If the displacements of the two sets of vanes are equal, speeds of the two rotors will be equal. If the displacement of the vanes of rotor 2 is nil, there will be no drive on rotor 3. If cam 18 is moved further towards rotor 2 flow to the rotor 3 may be reversed and hence the direction of rotation of the rotor 3 reversed. Pumping may take place equally on both sides of the rotor 2 with the fluid equally received on both sides of the rotor 3 to double the torque. To seal the spaces behind the cams 17, 19 to prevent circulation of fluid between the two sides of the pump or motor, fixed vanes 27, 28 engage slots in these cams. Equalization of pressure in the two pumping circuits is effected by ducts 29, 30, Fig. 15, which balance the pressure between the two pump outlets and the two pump return ducts. Conduits 25, 26 are connected to a reservoir (not shown) through non-return valves V 1 , V 2  to make up losses and a pressure relief valve V 3  relieves excess pressure in the system. In another application, for differential drive action between two motor units, e.g., differentially driving the driving wheels of a vehicle, a variable capacity, axially-sliding vane pump includes separate outlets (or inlets) 01, 04, Fig. 11, and separate inlets (or outlets) 03, 02 connected to motors M 1 , M 2 . The outlets are interconnected by a line BA fitted with a variable restrictor valve R and the inlets by a line CD. When the valve R is closed the two motors are supplied equally and independently and if of equal capacity will operate at the same speed irrespective of whether their loads are equal or not. With the valve R fully open differential drive action takes place between the motors if their loads are unequal, the more heavily loaded motor slows down and the less heavily loaded motor increases its speed so that the sum of the speeds of the two motors remains constant. At intermediate positions of the valve R any desired degree of differential action may be obtained. In another embodiment, a similar pump having two separate outputs includes in each output line a controllable valve operable to direct the output in that line to either motor or share it between the two motors. The outlets from the two motors are connected to two separate pump inlets by a line which includes a balance line connected through a non-return valve to a reservoir to make up any losses in the system.