| Crankshaft complex turning lathe（National invention patent has been open）processed crankshaft main journal and new crankshaft connecting rod neck newmachine. It is like linkage to make the tool following link neck for cutting cylindricalsynchronous, to achieve a clamping and complete the main journal and the neck ofthe cylindrical turning processing. The design and research of it will effectivelyimprove the processing technology of crankshaft, reduce costs and improve themachining quality and efficiency of the crankshaft. According to the workingprinciple of the machine, the tool do cylindrical synchronous cutting movementwhich follow the link neck, so the crankshaft and the crankshaft (tool installed on thetool) must have high precision of synchronization. Also according to the processingtechnology of the machine, the crankshaft is cutted by three cutting tools, in order toachieve "one clamping, finishing all over", it is very necessary to design a tool changedevice. This paper completed the following research work:(1) Complete the analysis of synchronization error between the crankshaft andtool carrier. Through coordinate system transformation, it is completed thetheoretically prove that the synchronization of the crankshaft and the tool carrier isprecise and sensitive to processed crankshaft. According to the requirement ofroundness tolerance of the crankshaft which is semi-finishing, deduce thesynchronization error range of the crankshaft and the tool carrier.(2) Calculate the transmission error of the existing main transmission systemwhich has the gear pair clearance, it is concluded that the transmission error is morethan the required roundness error. Points out that the gear and spline transmissionerror can lead to the crankshaft and the tool carrier unsynchronized because of theaction of gravity and cutting force.(3) Completed the optimization design of main drive system. Based on the abovetheoretical analysis and the influence factors, proposed two kinds of schemes forincreasing accuracy of crankshaft and tool carrier synchronization. One is to shortenmain drive chain, meanwhile To deduce the variable distance of the hanging wheel transmission and the relationship between the gear size and stretching angle. Putforward the design of main drive chain transmission of zero tolerance, adopted doublegears transmission, give the parameters of the relationship between the transmissionmethod and the calculation formula. Another method is to improve the design of toolcarrer at the power input. With the method of friction force to offset the affection ofgravity and cutting counterforce. By eliminating the acceleration of tool carrier madeby gravity and cutting force, Reduced the machining out of sync error.(4) Designed a set of tool change device which fit for the crankshaft compositeturning machine, maped out the overall design of the tool change device and parts. Inorder to reduce as much as possible the quality of the device, the paper completed thetopology optimization for the device. On the premise of meet the stiffness,reduction in the quality of the tool device body, finally design a set of high repeatpositioning accuracy, high precision indexing and light quality tool change device. |
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