The Research Of Crankshaft Gear Interference Fit Technology

The paper is aimed at the engineering problem that the crankshaft gear of a model diesel engine often fight tooth. Based on the finite element analysis, through traditional theoretical calculation analysis, we can conclude that excessive interference fit is the major factor of tooth fight of the crankshaft gear. But, traditional theoretical calculation analysis has some limitations. Therefore, the finite element method was used in this article to systematically study the Interference technology of the crankshaft gear. The relation between the related structural dimensions of interference fit, the contact state, the running state and the crankshaft gear stress was mainly investigated. The study showed that the structural dimensions played an important role the crankshaft gear stress. Based on these, on analyze the impact law of the structural dimensions affect to the interference fit was mainly focused. The results provided a reference to the crankshaft gear interference design.Based on thick-walled cylinder theories, though analyzing, we can identified that the magnitude of interference range which meeting the transfer torque as lower limit, no plastic deformation occurred as upper limit is 0.015mm to 0.26mm. On Theory of thick cylinders, assuming that the contact surface pressure is asymmetrical ,under this circumstance, the speed, temperature, friction and other factors cannot be considered, but the actual contact state and operation state are more complex, so it is necessary to use the finite element method to analyze and calculate.In this paper, a crank gear interference model of finite element analysis was built by ANSYS, then the distribution law of crankshaft gear stress and contact pressure of different interference was studied. Compared the analysis result to theory of thick cylinders, the effectiveness of the interference fit finite element analysis was verified. Based on this, the relationship between diameter of the gear, crankshaft diameter, surface contact length, tooth fillet, friction coefficient, temperature, speed and the stress of the crankshaft gear was discussed by ANSYS, and the main factors which affect interference fit, such as gear diameter, crankshaft diameter, surface contact length was mainly analyzed.