抄録
Vane pumps come in two basic forms: pressure balanced, fixed displacement and pressureunbalanced, variable displacement. In an unbalanced variable displacement vane pump, vanessweep against an adjustable cam ring. Moving the ring against a spring changes the radial travel ofthe vanes, varying pump displacement. This design imposes side loads on the bearings and bendingmoments on the shaft, limiting the pump operating pressure range and its possible applications.
We introduce a New Concept of a Pressure Balanced Variable Displacement Vane Pump. In thenew concept the vane pump has a thin ring installed concentric with the rotor. To vary pumpdisplacement, two equal opposed forces are applied to the ring (vertical), in effect “squeezing” it toan elliptical shape. The displacement is controlled by the amount of out-of-round ring deflection, the greater the squeeze, the greater the ellipse, the greater the flow output.
The stresses in the ring is kept well within the elastic range of the ring material, so when the deflecting forces are removed, the ring returns to its circular shape and displacement returns to zero.Now, applying the forces along the (horizontal) diameter will exchange suction-pressure portstasks, in effect, making the pump bi-directional. The new pump has a fast response, andincorporating such a pump in servo systems, would make the basis for a fully hydrostatic low costvane type hydraulic pump system.
