The invention discloses a method for recovering
potential energy of a movable arm of a hydraulic digging
machine and a device thereof. The method comprises the following steps: firstly, the
potential energy is stored through an energy accumulator in the retraction process of a
hydraulic cylinder; and secondly the
stored energy in the energy accumulator drives a generator to generate
electricity, thereby realizing the
recovery of the
potential energy of the movable arm of the hydraulic digging
machine. A mode for storing the potential energy is to convert the potential energy into pressure energy. The energy accumulator and the generator are connected through a
proportioning valve so as to control the rotational speed of the generator. The method realizes high-efficiency
recovery of the potential energy of the movable arm of the hydraulic digging
machine; the principle of the method is to skillfully change the working time of hydraulic oil for power generation through the function of
energy storage of the energy accumulator and provide effective buffering for recovering the potential energy; in addition, through the throttling control of the
proportioning valve, the method reduces pressure fluctuation of the hydraulic oil in the power
generation process, realizes the adjustment of the working rotational speed of the generator, improves the working efficiency of the generator and further improves the efficiency of
energy recovery.