Optimization Of Working Cycle Time For Hydraulic Backhoe Excavator

Hydraulic excavator aims at high efficiency, high reliability and comfort of operation. However, there is still a wide gap between domestic and foreign excavators in technical level of these aspects. The efficiency of hydraulic excavator depends on its working cycle time which is also one of the primary performance indexes of the complete appliance. For this reason, the modeling and optimization analysis of working cycle time for excavator are carried out in this thesis. The full text is divided into the following five chapters:The first chapter elaborates the research background and significance of this subject. Furthermore, it summarizes the research situation of hydraulic excavator both here and abroad as well as the key technology involved in subject study, and points out the lack of research on working efficiency of excavator. Thus the main research contents of the project are made clear.The second chapter analyzes typical working cycle process for hydraulic excavator and rotary motion of revolving frame including the movement of every phase concretely, so as to find out mathematical modeling strategies of working cycle time and rotation time. In combination with working principle of hydraulic systems, calculation models of cycle time based on load-sensing system and full-power control variable system with double-pump and double-circuit are established respectively.In chapter three, an optimization model for hydraulic excavator is set up based on load-sensing hydraulic system, in which the largest flow areas of hydraulic multi-way valves are taken as main design variables for the first time and working cycle time is taken as the main objective while the other performance requirements are also taken into consideration. In addition, two product optimization models with different types of hydraulic system are present. The results indicate an obvious improvement in working efficiency while the other performance indexes are also mostly improved, fulfilling generalized optimization of entire system and overall performance for excavator. The forth chapter establishes virtual prototyping model for hydraulic excavator co-using Pro/E and ADAMS, which is taken as a platform for running visual simulation of working cycle process for excavator. What's more, the simulation model and calculation model of working cycle time verify each other in results.Chapter five concludes the whole paper, followed by some suggestions on further research.