The main function of the gear shaft is to support rotating parts, achieve rotary motion and transfer torque and  power. Gear shaft has a series of advantages, such as high transmission efficiency, compact structure, long service life and so on. It is one of the important parts in the general machinery, particularly the engineering machinery transmission. The optimization of the gear shaft’s machining materials, thermal treatm -ent method and machining process will have great significance on the machiningqual -ity of the gear shaft and the service life. This paper discussed the machinery manufa- cturing process planning and fixture design of milling key of a “gear shaft” provided  by a enterprise. As for process planning and fixture design, there were two different plans for selecting the better one. The paper firstly analyzed the function of the gear s -haft and its mechanical properties, and then planned the machining process, finally, the fixture design. As gear shaft requires the higher machinery comprehensive properties, we usually select the forgings as the forging blank. It is very important for ensuring the processing quality of the gear shaft to arrange the  process route reasonably anddivide the processing stage. Using Fixture can reduce the auxiliary time, increase productivity, ensure machining accuracy, stabilize the processing quality, reduce the technical requirements for workers and expand the technology range of machine tool.  The subject is designed to gear design and gear machining process design. First, to design the gear according to conditions, then the gear design process, and to determine the overall layout design, then, for hobbing fixture design.

As a new transmission technology,the development speed of harmonic gear drive is very fast in recent decades. Harmonic gear drive mainly relies on the elasticdeformation to transmit motion and loads. With progress and development of the society, after several decades in harmonic gear drive appeared, not only scientific powers research it, also some industrial comparative developed countries put a lot of human and financial resources to develop this new transmission technology, scholars from different count…