The Simulation And Experimental Study On Heat Balance Of Truck Crane Hydraulic System

Hydraulic is a basic and vital transmission and control technology for truck crane. There are some inevitable losses, most of which convert to heat which will finally be released to the hydraulic system and result in the increase of oil temperature while energy transfers in the hydraulic system. High oil temperature plays a serious side effect on the work efficiency and operating performance, and even shortens the service life span of crane. Therefore, keeping the heat balance of hydraulic system in a reasonable range is meaningful for increasing the efficiency and reliability of crane, as well as market competitiveness of the crane manufacturing enterprises. Traditional design and calculation of heat balance involves in power loss, pressure loss and others of hydraulic system nodes, which is just regarded as the complement for functional design. Also the calculation, which is complicated and often results in large errors, cannot meet the precise requirements of heat balance design. Finding through research is that hoisting and rotating are the main heat conditions, so we determinate that these two work conditions form the crane work cycle and further we make a detailed analysis in reasons for heat production of hydraulic system. To simplify the heat balance calculation of hydraulic system and increase accuracy, we put forward a calculation method and make a derivation for it based on energy transferring rules in crane cycle conditions and the energy conservation law. Then we establish a mathematical model and we try to apply it to calculating the heat production of a particular hydraulic system. AMESim simulation software is used to build the thermal hydraulic model for the truck crane. Some of the parameters are optimized to research influences made by some key components on heat balance; meanwhile we indicate the different performances of various parameters on heat balance and put forward the recommendations for improvement after comparing the results of oil temperature rising. To verify the simulation results, we carry out a large number of experiments and find out the main heat and cooling components in hydraulic system, also we have assessed their heat and cooling efficiency. In the process of assessing the efficiency of triple pump, we put forward the thermodynamic method for pump and motor and also make a derivation for it. In the end, we make out a scheme plan to improve the crane and practice it in a real truck crane. By means of experiments, we test and verify that the scheme is effective.