Research On The Torsional Deformation Of A Crankshaft's Compound Follow-up Turning

Crankshaft is one of the most important parts in the engine, it changes the pistion's linear motion to the crankshaft's rotary motion. In the part of crankshaft machining, due to the axis of the connecting rod neck has a eccentric relative to the spindle axis of the crankshaft, it is difficult to cutting the connecting rod.Currently, the crankshaft production line is mainly made up of common machine tools and special machine tools, with relatively low production efficiency and automation. In China, the crankshaft machining equipment mainly rely on being imported from foreign country, which greatly increase the costs of the crankshaft machining. To address this issue, a new kind of the crankshaft connecting rod neck machining tool has been designed, it is called the composite lathe. The composite lathe can cut all the necks in one setup.The crankshaft must have a high precision, and so does the composite lathe. This article studies the machining accuracy of the composite lathe. The main contents of this article are as follows:1,Introducing the operating principle of the composite lathe, studying the factors that affect the cutting force, and computing the cutting force from the empirical equation. And also introducing the mechanical characteristics of the crankshaft in the cutting process, at last get the torsion's regulation.2,Demonstrating the importance of the error compensation, which has to get the error regulation first. Studying the sources of error from two aspects, that are operation error and workpiece error. Analyzing the phase error of the rod neck caused by the relative phase error. At last, determining the relative error and the cutting force are the main factors of the machining error.3,Studying the model of the composite cutting, under this model, analyzing the regulation of the cutting force. Then, computing the stiffness coefficient by ANSYS. With the cutting force and stiffness coefficient, the regulation of the deformation could be calculated. And so the regulation of the phase error can be calculated too.4,The experimental study is also important for the study of the composite lathe.Based on the structure of the composite lathe and the regulation of the torsion, a test system is designed to test the torsion of crankshaft when it's working.The contents of this thesis has a practical value to the crankshaft machining technology and the automotive industry, it has broad application prospect.