| Due to its high degree of automation,fast forming speed,and better dimensional control accuracy,fast forging hydraulic presses are widely applied in shipbuilding,nuclear power,aerospace,metallurgy,and machinery manufacturing industries.However,it is aslo famous for its high installed power,high energy consumption,and low energy utilization.Therefore,research on the energy transmission and energy-saving technology of fast forging hydraulic presses can effectively promote its technical progress,improve competitiveness,and achieve energy-saving and emission-reduction goals in industrial manufacturing.Mismatch between the installed power of the hydraulic drive system and the load power and the low energy transmission efficiency are the main reasons for the high energy consumption of fast forging hydraulic presses.There still exists some questions unsolved by current researches.For example,why does the hydraulic system generate energy loss and how does the energy loss transform during service? The power unit is designed according to the maximum load power,but the movement of the fast forging hydraulic press has typical periodicity and timing.As it runs under low load and no load most of the time,the problem of excessively rudundant energy and serious waste due to the low-load rate is still unsolved? How to solve the energy transmission loss and low transmission efficiecny due to the numerous equipment and long pipelines? In view of the above problems,this paper established an energy dissipation model of a fast forging hydraulic press.On the basis of the energy loss mechanism,this paper proposes four high-efficiency transmission strategies for a fast forging hydraulic press from the perspectives of mechanical energy storage,hydraulic energy storage,energy transfer efficiency and energy recovery.The specific research work is as follows:On the basis of analyzing the composition and process of fast forging hydraulic press,the energy flow model of the forming process and the energy dissipation model of each energy transfer unit is established.The energy loss mechanism of the energy transfer process is studied,thereby solving how the energy consumption of the fast forging hydraulic press is generated and how the energy consumption is transformed,and laying a theoretical foundation for improving its energy efficiency level.Aiming at the mismatch between the installed power and the load power,from the perspective of the mechanical energy storage,a novel hydraulic power unit based on the flywheel energy storage system is proposed.The flywheel and the motor are rigidly connected,and the power unit adopts a variable frequency drive mode.The inverter-driven motor drives the flywheel to store the redundant hydraulic energy during the low-load stage and release it during the high-load stage,so as to realize the efficient reuse of the redundant energy of the hydraulic system and reduce the installed power of fast forging hydraulic presses.The experimental results show that the novel hydraulic power unit mentioned herein can reduce the installed power of 30%,and increase the energy utilization of 40%.From the perspective of hydraulic energy storage,a new type of hydraulic energy storage system based on an accumulator-two-way boosting system is proposed,and the operation strategy coordinating the boosting system is proposed according to the forming task.At noload stage,the main pump units fill the accumulator.At low-load stage,the main pump units and the accumulator supply energy to the main cylinder.At high-load stage,the supercharger supplies energy to the main cylinder.Through the cooperation of the accumulator and the boosting system,not only the pressure fluctuations generated during the boosting process are reduced,but also the working efficiency and the boosting stability of the boosting system are improved.Furthermore,the energy storage efficiency of the accumulator and the energy utilization of the hydraulic system rate are significantly improved,thereby reducing installed power of fast forging hydraulic presses.Aiming at the large energy loss and low transmission efficiency caused by long and circuitous hydraulic energy transmission pipelines and numerous valve blocks,a hydraulic machine structure optimization strategy is then proposed to change the traditional planar layout.The hydraulic equipment are arranged vertically and layered according to functional requirements,which could reduce the transmission distance of the hydraulic energy between the pump station and the actuator,and realize the shortest hydraulic transmission pipeline.Thereby,reducing the energy loss in the transmission process and improving the transmission efficiency and response speed of the hydraulic system are all realized.Compared with the traditional planar arrangement,the energy loss of the vertical press in a working cycle(3s)is reduced by 229.66 k J.During the unloading stage,the hydraulic cylinder,frame,and pipeline of the fast forging hydraulic press store a large amount of hydraulic energy and elastic potential energy.To achiever recovery and reuse of this part of enrgy,an energy recovery system is them proposed.By introducing a buffer device into the cooling system,the unloaded oil is buffered and decompressed,which could be as a source of circulating cooling oil,and then replaces the conventional cooling circulating motor,thereby reducing the installed power.Furthermore,it can also provide an oil source in the fast falling stage,thereby realizing the recovery of waste energy,and improve the energy utilization of the hydraulic system.In summary,this paper has conducted in-depth research on the high-efficiency transmission and energy-saving technologies of the fast forging hydraulic press for its high energy consumption characteristics.The research results are of great significance for reducing the energy loss of the fast forging hydraulic press,improving the energy efficiency of forming processing,and developing a low-carbon green economy. |
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