Study On Compensating For The Synchronization Precision Of Mainshaft And Tool Holder Of The Crankshaft Machining Complex Lathe

Crankshaft is an important component of automotive and marine engines, which is responsible for turning the up-down motion of the piston into the rotation of the output shaft of the engine. In the part of the crankshaft machining, the processing of the Crankshaft connecting rod neck is a difficult, because the axis of the connecting rod neck has a eccentric relative to the spindle axis of the crankshaft.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 countries, which greatly increase the costs of the crankshaft machining. To address this issue, a new kind of the crankshaft machining tool has been designed.The processing method of this new type of lathe is special, which has a high demand for the rotary movement synchronization of the headstock mainshaft and tool holder. This article makes the transmission chain from the headstock mainshaft to tool holder input as an object and studies the synchronization accuracy and the compensation control of the transmission chain. The main contents of this article are as follows:1. According to three-dimensional model of headstock-tool holder transmission chain, the object model of the transmission chain is established. We have analyzed the sources of rotation error. In particular, for the composite error of the meshing teeth, we give a calculation method based on probability statistics, and with which the rotation error of the transmission chain has been calculated initially.2. Studying the dynamic model of the transmission chain of headstock-tool holder. The stiffness-damping model of the transmission chain has been established, based on the gear pair torsion model and gear-rotor system model. The analysis model of the composite error of the meshing teeth also has been built, which is based on the theory of the composite error of the meshing teeth. We have used the corresponding knowledge of theoretical mechanics to establish the simultaneous differential equation, according to the analysis model. Using the Laplace to solve the simultaneous differential equation, we get the corresponding rotation transfer functions, and finally obtain the total rotation transfer function. With the help of MATLAB, we can analyze the response of the total rotation transfer function. What's more, the response of rotation transfer function of the model with different load torques can be compared.3. Studying the dynamic model of the transmission chain between the output of the servo motor and the input of the tool holder. Though building the analysis model and mathematical model, we can obtain the total rotation transfer function between the output rotation of the servo motor and the rotation error of the headstock mainshaft and the tool holder.4. We have established the control model of the synchronization precision compensation for the mainshaft and tool holder of the machine. Using MATLAB software, we make a correlation analysis on the static characteristics and dynamic characteristics of the control model. The control precision of compensation control has been verified.