Simulation of dynamic phenomena in a high pressure variable displacement axial piston hydraulic pump
Substituting a valve plate-based commutation unit with a hydrostatic-load-free commutation bushing controllable with a signal of negligible power, that could be applied in constant and variable displacement pumps introduced a different approach to the design of commutation units in multi-piston axial hydraulic pumps.
Conducted research showed that valve plate-based commutator is responsible for over 50% energy loss. The new idea assumed a stationary cylinder block and the replacement of the valve plate with a camdriven commutation unit that would be totally unloaded hydrostatically. That eliminated main source of mechanical losses as well as a flow resistance loss. Additionally, the dead volume was significantly reduced, which helped to reduce the pump noise level and resulted in a great decrease in power needed to control the pump displacement. That allowed to eliminate a servomechanism and the direct control of the pump displacement with a low power element. However, the new design presented a challenge in the form of pressure peaks occurring in the working chamber, which were difficult to eliminate. This article presents attempts to solve problems connected with those dynamic phenomena.
Keywordshydrostatic machine, axial multi-piston pump, dynamic phenomena,
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