| Motor grader is widely used in infrastructure and national defense construction. It is one of the indispensable equipment in modern mechanized construction. Currently domestic motor grader is mainly based on hydraulic driving system. Hydraulic motor grader features strong load-adaptive capacity, but with the problem of narrow high-efficiency area. With the development of multi-gear transmission and automatic shifting technology, it becomes possible to realize automatic shifting in hydraulic motor graders, which has great practical significance for improving work productivity and reducing driver’s labor intensity.The automatic shifting key control technology of 215 hp hydraulic motor grader is studied in this paper. By investigating and summarizing automatic shifting technology of domestic and foreign motor graders, the objectives, the requirements and the technical characteristics of motor grader about automatic shifting are put forward. Based on characteristic analysis to the driving system of 215 hp hydraulic motor grader, the automatic shifting range, the mode, and the scheme are posed. Three-parameter automatic shifting schedule based on speed, throttle opening, and current gear is proposed. The shifting strategy is developed by discretizing the throttle. The shifting time under different throttle opening is especially analyzed and calculated, and the optimal shifting control curve is presented. The lock-up control methods of torque converter are studied, and the automatic lock-up and unlock-up conditions of lock-up clutch based on load status are put forward. The factors influencing automatic shifting quality are analyzed. The methods of improving shifting quality are given. According to the three-parameter shifting schedule, the automatic shifting control system based on special controller is designed. The hardware and software of the control system is proposed, and the flowcharts and time sequence diagrams of the key control algorithms are given. |
PDF Full Text Request