Design of A New Hydraulic Accumulator for Transient Large Flow Compensation

Hydraulic accumulators are widely used in industry due to their ability to store energy and absorb fluid shock. Researchers have designed kinds of novel accumulators with better performance in these specific areas. However, the pressure in these accumulators decreases significantly when the fluid oil is continuously supplied from the accumulator to the hydraulic system. This limitation leads to a transient large pressure drop, especially in a small hydraulic system with varied working frequency. In this research, a combined piston type accumulator is proposed with a relatively steady pressure property. The gas chamber and the fluid chamber are separated by a cam mechanism. By using the nonlinear property of the cam mechanism, the nonlinear relationship between the pressure and the volume of the gas can be offset. Hence, the fluid pressure can be maintained in a relatively steady range. The defect of the traditional accumulator in the frequency varied system is analyzed in detail. Then, the structure of the new accumulator is proposed and modeled based on the traditional piston type accumulator. The mathematical equation of the cam mechanism is built under the assumption that the nitrogen gas works in an adiabatic process. A simulation system based on the Amesim platform is constructed, and mathematic equations of the system are given. Preliminary experiments are conducted to evaluate the performance of the new accumulator. The comparison results show that the adaptability of the new accumulator is obviously larger than that of the traditional accumulator in a frequency varied system.