Hydraulic pump

– Gear pumps:
– Simple and economical pumps
– Volumetric efficiency is around 90%
– Pressure is created through meshing of gear teeth
– Modern gear pumps are reliable and quieter
– Gear pumps gradually wear down, reducing volumetric efficiency

– Rotary vane pumps:
– Positive-displacement pumps
– Vanes mounted to a rotating rotor inside a cavity
– Various vane designs used for tight seal and minimal wear
– Spring-loaded or hydrodynamically loaded vanes
– Critical element is how vanes are pushed into contact with housing

– Screw pumps:
– Consist of two intermeshing Archimedes screws
– Used for high flows at low pressure
– Low sound level but efficiency is not high
– Hydraulic reaction force is axially opposed to flow direction
– Ways to overcome the problem include using thrust bearings or hydraulic balance

– Bent axis pumps:
– Exist in fixed or adjustable displacement designs
– Two basic designs: Thoma-principle and Wahlmark-principle
– Best efficiency among all pumps
– Can work with working pressure up to 350–420 bars
– Variable-displacement pumps allow for careful oil flow adjustment

– Inline axial piston pumps:
– Variable displacement pumps can alter fluid discharge and system pressure
– Can adjust based on load requirements, pressure settings, and even electrical signals
– Potentially power-saving compared to constant flow pumps
– Suitable for systems with non-constant fluid flow requirements
– Offer various compensation techniques for different applications