The Method Of Generating Multi-stages Drive-Train Load Spectrum And Using In Concrete Mixer Reducer

The question of determining the design loads of multi-stages and multi-loadcases drive-train according to measuring load spectrum which was discussed. According to researching the single lever design load method which was used to determine design load, the shortages of using single lever design load to determine the design loads of multi-stages and multi-loadcases drive-train were discussed. Based on the single lever design load method, a new multilevel design loads method, which takes the differences of materials, loads'circles and amplitudes of every gear in the drive chain into account, was proposed. The new method was verified by the design process of a reducer used for a cement mixer.In the verified process, a method of indirect torque measurement was studied. The primeval load datas were obtained from the new method and analysed. With the primeval load datas, all case load spectrum of the reducer gear of cement mixer was built. According to the drive-train project of drive-train system, the fatigue load spectrum of every gear was built. Based on all case load spectrums, the single lever design load method was used to calculate the bending equivalent torque and contacting equivalent torque of gears. Based on fatigue load spectrum, the multilever design load method was used to calculate the bending equivalent torque and contacting equivalent torque of gears. The different results from the two different methods were compared. The reson from the different results was analysed.Based on the bending equivalent torques and contacting equivalent torques of gears calculated with the multilever design load method, the gears of drive-train were designed. The safety factors were calculated with all case load spectrum and two equivalent torques. Software of MASTA was used to calculate the safety factors of gears. The deformation of system was considered, and standard of ISO 6336 was used in MASTA software. Based on all case load spectrums, the parameters of gears were optimized. Using all case load spectrums, the damage ratios of gears were calculated. Gears modification analysis was made on the load of maximum damage ratio. The method and value of modification was determined on this load. Based on the modification model, the safety factors of gears were calculated again. The safety factors got by single lever design load could not meet the requirements of design standards, and the safety factors got by all case load spectrum and multilevel design loads method do very well. Theoretical rationality of multilever design loads method was verified.Virtual simulation could not replace the fatigue testing. For proving the practical reasonable of the multilever design load method, the load and method of the accelerated fatigue test was studied.The accelerated fatigue test was made. The result of testing was met the requirements of design standards. Although the reducer worked very well in practice, the shortage of the single lever load design method was verified.The results suggest that the multilevel design loads method is reasonable.