Study on characteristics of a novel water-hydraulic pump with electro-hydrostatic actuator

In order to resolve the issues of wear, limited lifespan, and excessive noise commonly associated with traditional swashplate axial piston pumps in aqueous environments,while meeting the reliability requirements for hydraulic pumps in demanding conditions such as underground coal mines,a novel water hydraulic pump has been developed that integrates an electro-hydrostatic actuator. This pump features two parallel cylinders driven by an innovative two-dimensional piston pump electro- hydrostatic actuator, resulting in a high power-to-weight ratio for the entire system. The structure and operational principles of the hydraulic pump driven by the electro-hydrostatic actuator are first presented. Following this, a mathematical model for the electro- hydrostatic actuator system is established and subjected to simulation analysis. Subsequently, a prototype testing platform is constructed to perform operational tests, no-load characteristics assessments, and load performance evaluations on the prototype. The experimental results facilitate a comprehensive analysis of the fundamental characteristics of this novel pump design. Finally, the findings from these experiments are utilized to infer the output performance parameters of the pump when powered by motors of various power ratings. Experimental results indicate that the prototype hydraulic pump exhibits minimal output flow pulsation, low noise levels, and a volumetric efficiency exceeding 84%. Moreover, the volumetric efficiency increases with rising motor speeds and decreases with elevated load pressures. The rate of pressure pulsation within the pump chamber diminishes as both speed and load pressure increase, while the intensity of pressure fluctuations remains relatively stable irrespective of load pressure variations. Under varying loading pressures, the pressure pulsation within the water hydraulic pump chamber is approximately 0.5 MPa. While the pump output exhibits pulsation, the large cross-sectional area of the water piston minimizes velocity fluctuations. The water piston operates at a constant speed, resulting in reduced flow and pressure pulsations in the water hydraulic pump output. This enhances the overall system performance and reliability. Furthermore, the force acting on the water piston aligns with its direction of motion, eliminating additional friction caused by overturning moments in conventional pumps. Minimal wear occurs between the water piston and cylinder body, enabling sustained high volumetric efficiency throughout the entire service life.