| There are two types of cab overturning mechanisms: mechanical and hydraulic.The mechanical overturning mechanism has a small turning torque and is suitable for light and medium truck cabs.The hydraulic overturning mechanism has a large overturning torque and is suitable for heavy truck cabs.Generally,the hydraulic overturning mechanism system is designed for insufficient consideration of the working condition characteristics in the suspended state,some failures will occur in the hydraulic overturning cylinder,among which the excessively mounted resistance will cause the vehicle to pass through the bumpy road surface.The smoothness and comfort of the ride may even be damaged due to excessive resistance,and the connection between the hydraulic overturning cylinder and the cab may be damaged.Aiming at the current problems of the hydraulic overturning cylinder,the simulation analysis and optimization design of the hydraulic overturning mechanism of a heavy truck cab are carried out in this paper,and the improvement of the optimized hydraulic overturning system is verified by experiments.Firstly,in response to the problem that the expansion orifices are noncircular orifices with unclear flow characteristics,etc.In order to analyze the flow characteristics of the noncircular orifices in the overturning cylinder of the hydraulic overturning mechanism of the heavy truck cab,the flow field finite element analysis method was used to analyze the flow through the expansion orifices at different temperatures.Numerical analysis was performed,and function fitting was performed on the numerical results of multiple sets of flow field analysis to obtain the orifice flow characteristic equation of the expansion orifice at different temperatures,and the mathematical relationship between the temperature and the orifice shape coefficient.Secondly,the hydraulic overturning cylinder is placed in the heavy truck cab suspension system,and the AMESim heavy truck cab hydraulic overturning mechanism suspension state simulation model is built,including the AMESim hydraulic overturning cylinder model and the heavy truck cab suspension system model,and the heavy truck cab suspension system model is analyzed.The performance and influencing factors of the cab hydraulic overturning mechanism in the suspended state.Thirdly,through the Fluent simulation analysis,the flow capacity of the expansion orifices of the two orifices and the expansion orifices of the four orifices was compared and analyzed.On the basis of the simulation model of the suspension state of the hydraulic overturning mechanism of the cab,the reasons for the high resistance in the suspension state were analysed,the internal diameter of the return line L1 of the hydraulic overturning mechanism was optimised,and the internal diameter of the return line L1 that meets the flow through the suspension state of the hydraulic overturning mechanism of the cab was derived.At the same time,in order to ensure the cab overturning performance,the hydraulic overturning cylinder structure is optimized and improved,the designed reverse check valve is installed,the optimized simulation model of the suspension state of the hydraulic cab hydraulic overturning mechanism is built,and the rationality of the optimized simulation results is verified.Finally,according to the test conditions,the AMESim software is used to simulate and analyze the hydraulic overturning cylinder,and the hydraulic overturning cylinder is tested and verified.The rationality of the simulation model of the hydraulic inversion cylinder is verified by comparing the hydraulic inversion cylinder test and the simulated hanging state resistance curve.Comparing the hydraulic inversion cylinder before and after optimization,it can be seen that the optimized hydraulic inversion cylinder’s suspension state resistance is significantly reduced.There are many which in turn reflects the rationality of the optimization analysis,and provides a certain reference value for the research of other models. |
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