Advanced Materials Research Vol. 619

Abstract: The paper gives an introduction of the structure and working principles of the new gap-type electro-hydraulic servo valve and advances the performance law of throttle by a comparative analysis of the performance of gap-type electro-hydraulic servo valve and the traditional rectangular orifice. In the meanwhile, combined with the introduction of the coordinate of working state, this paper aims to solve such complex problems as the design parameters of hydraulic components and provide a basis for the visual design of the performance of hydraulic components and cavity control parameters of servo valve and the main valve.

Abstract: The fire accident of heavy mineral self-dumping truck is one of the most serious disaster in mine safety production. Research on the reasons that cause fire accident is an important study for ensuring safety production. By analyzing three elements that constitute self-dumping truck fire accident, the characteristics and easy ignition points as well as major combustion parts of self-dumping truck fire accident, we confirm that the hydraulic system leakage is the major factor that causes fire. To find out the fault reason of hydraulic system oil leakage, we analyze the composition and working principle of self-dumping truck, establish leakage fault tree of hydraulic system. Based on logic relationships between each fault and fire, we get the following conclusion: hydraulic tubing damage is the highest probability event that causes oil leakage fault. In addition, we should pay attention to spare parts management factor, correct driving factor and equipment management factor. We also propose the prevention measures of leakage and fire

Abstract: Based on the analysis of the working mechanism of positive control system of excavator, a new type of positive control system with synthetic pilot pressure was designed. The hydraulic model based on AMESim was established. The dynamic simulation of this new type model was done, and was compared with conventional positive control system. The results of the simulation show that the precision of the matched flow and the power efficiency is higher in the positive control system with synthetic pilot pressure than in the conventional positive control system.

Abstract: This paper creates the model of the hydraulic control system and does simulation by using powerful function of modeling and simulation of MSC. Easy5. To help support the equipment of the hydraulic control system Vertical Shaft for example Firstly, creates the model of the Vertical Shaft hydraulic control system through the software MSC. Easy5. Secondly, input relevant simulation parameters and do simulation. Finally, analyze the results of simulation.

Abstract: For the purpose of optimizing the dynamic characteristics of large forging equipment multilevel cartridge valves, according to the structure and principle of the Rexroth’s LC series cartridge elements, using AMESim simulation software, the influence of forging equipment cartridge valves switching characteristics be discussed respectively from the damping R2, the damping R1, the load pressure. The results show that the damping R1, the damping R2, the system pressure, and the work load to cartridge valves switching characteristics have certain effect. The research gives a method for analyzing and adjusting the cartridge valve response characteristics.

Abstract: The simulation loading system with secondary regulation contains hydraulic coupling and mechanical coupling. This study analyzed the influence on the performance of the system caused by coupling disturbances. Control performance under coupling disturbances with PID control was simulated by MATLAB. With the increasing of the pressure fluctuations, fluctuations of torque control and speed control system all changed. The influence of torque control system is greater than speed control system. When the torque fluctuated, the drive speed appeared large fluctuation error and the error was direct ratio to the torque fluctuation. But the torque system is immune to the speed fluctuation. In order to eliminate the influences, a decoupling controller has been designed. Control performances under the disturbance of hydraulic and mechanical coupling with decoupling controller and without decoupling controller were simulated. The results showed that, when added decoupling components, the system was decoupled, the negative influence of the coupling interferences to the system was reduced or eliminated, the control property was improved.

Abstract: Hydraulic technology is widely applied in various fields of national economy, so the performance of hydraulic system directly influences all aspects of the economic benefits. The status of hydraulic oil is important for the working performance of hydraulic system.The pollution of hydraulic oil is a reason，which causes the fault of hydraulic system And it will cause the failure of system and loss of benefit. So it's very important that the fault of hydraulic system be diagnosed and treated. This paper introduces hydraulic oil pollution and the method of diagnosing and treating it.

Abstract: Along with the rapid development of China's economy, the CFD technology has become an indispensable new technology in industrial production, and it plays an important role in the development of industry. Using computational fluid dynamics software called FLUENT. The investigation was carried out in a mixer, which its internal flow of the 3-d numerical simulation. The unstructured tetrahedron grid and unsteady multiphase turbulent calculation model were used to analyze the mixer internal fluid concentration, speed and turbulent kinetic parameters e.g., which produce changes and distributions with the different stirring shaft speed, and reveal the law of internal flow. Through the simulation result, can conclude that the numerical simulation method can truly reflect the interior complicated flow state of mixing machine, and can provide theory basis for the design and improvement of the mixing equipment.

Abstract: A digital hydraulic valve is a new control theory and method, it is through the electronic control unit installed in a conventional valve, and integrated processing, the formation of a wide variety of digital valve，By the digital-to-analog conversion element is directly connected with the computer. Using the computer output pulse number and frequency to control electro hydraulic system pressure and measurement. The system proposed can make the hydraulic system has the advantages of high efficiency, high speed, high reliability. And used Matlab/Simulink software to control system performance simulation analysis, experiment and simulation results show that, this system has great application prospect and practical value.

Abstract: In order to optimize the dynamic characteristic of hydraulic system of large forging equipment. It based on the model of one company of a certain aero-engine hydraulic system of hydraulic hammer forging, analysis the composition and working principle of hydraulic systems. Using simulation software AMESim, simulate the model of hydraulic systems and by changing the system pressure, flow and effect of the hammer-head stroke to explore this kind of switching characteristics of forging equipment’s hydraulic system. The result shows that this kind of simulation models can reflect the working status of hydraulic hammer well, and provide a technical reference for analysis and tuning equipment that with similar to forging equipment.