Research On Basic Applied Technology Of Follow Finishing Crankshaft Journals With Abrasive Belt

The crankshaft is the key part of the internal combustion engines and diesel engines, the journal of the roundness errors, surface quality and surface support ratio have a directly impact on the fit accuracy, rotation accuracy, friction, vibration and noise, and at the same time impact on the life of the crankshaft. As the surface of the journals would appear deep grooves, create higher peaks and valleys after wheel grinding, and then lead to friction and wear between crankshaft journals and gearing in work, after working for some time, the theory size would smaller than the actual size, and then the vibration and noise were increased, thus the application of engine performance was seriously affected. In order to improving the surface quality, support rate and the surface finish of the crankshaft journals, achieving the high flexibility, high efficiency and high precision of crankshaft machining, so the follow finishing technology with abrasive belt was used for solving the eccentric movement of crankshaft journals.This article mainly on achieving the technical requirements of finishing with constant pressure, and research on the key technologies, which including the impact on the finishing accuracy for the follow movement of belt mechanism and the relationship between the vibration of follow mechanism and surface waviness. The main research work as follows:Firstly, the process of finishing crankshaft main journals by using the existing grinder, the surface quality of the crankshaft main journals and the abrasive belt life were discussed as the condition of different finishing block in different cycle-time and different vibration frequencies, and then the experiment basis was supplied for the design of the grinder for follow finishing crankshaft journals with abrasive belt.Secondly, the kinetic characteristic of the follow finishing crankshaft journals was analyzed, and the movement model of the constant linear speed finishing was proposed, obtained that change the crankshaft rotation speed is necessary. And the errors were analyzed which caused by the movement model of follow finishing crankshaft journals with abrasive belt, and the variation of errors were established between dimensional accuracy and shape precision, and at last the error compensation mathematical model was obtained.And then, considering the characteristics of follow finishing, it was divided into two stages, grinding and finishing, and at the same time the force of grinding were analyzed, at last, the formula of forces which applied to follow finishing was established. While the 6-degree of freedom dynamic model for the follow finishing crankshaft journals with abrasive belt is established, after decoupling dynamics equations by modal analysis, the effects of forced vibration is calculated.Finally, detailed design on the all key components of Folfina crankshaft was introduced based on the theory of follow finishing, combined with advanced design of Folfina crankshaft at abroad and the technology requirements of constant pressure in finishing. The technical requirements and the key components of the Folfina crankshaft are described in details for the four-cylinder diesel engine crankshaft finishing, at the same time, the performance and the problems of the grinder were summarized.