渐开线花键具有良好的导向性、定心性及大的扭矩传输能力，被广泛应用于航空减速器、航空发动机涡轮泵等动力传输系统中。航空花键副在飞机起飞、巡航、着陆过程中承受变扭矩、轴向力以及弯矩形式的波动载荷，因此航空花键副使用过程中的稳定性和安全性显得尤为重要。本文研究的高硬度细长空心双头花键轴是一种特殊结构的渐开线花键， 是发动机附件传动系统中重要零件之一，属于轴类零件，特点是长径比大（大于27），两端都有需要氰化处理的渐开线花键，在实际工作中，靠花键与功率输入输出轴连接，具体地，发动机各个附件的动力都是涡轮的动力，经过双头花键轴的渐开线花键副从涡轮的主轴传递到附件机匣的各个运动中去的。由于双头花键轴它所传递的功率十分庞大，且转速较高， 因而要求渐开线花键副传动非常平稳。鉴于此，以高硬度细长空心双头花键轴为研究对象，基于其结构特点及加工工艺难点，拟定多条工艺路线并进行验证，以达到提高该类零件批量加工的稳定性。
Involute spline has good guiding, centring and large torque transmission capacity, and is widely used in power transmission systems such as aeronautical gearboxes, aero-engine turbopumps and other power transmission systems. Aero spline vice is subjected to variable torque, axial force and fluctuating load in the form of bending moment during the take-off, cruise and landing of the aircraft, so the stability and safety of the aero spline vice in the process of use is particularly important. The high hardness slender hollow double spline shaft studied in this paper is a special structure of involute spline, is one of the important parts in the engine accessory drive system, belongs to the shaft parts, is characterised by a large length to diameter ratio (more than 27), there are both ends need to be cyanide treatment of the involute spline, in practice, by the spline and the power input and output shaft connection, specifically, the power of the engine accessory power is the power of the turbine, the power of the turbine, the power of the turbine, the power of the turbine, the power of the turbine, the power of the turbine, the power of the turbine, the power of the turbine, the power of the turbine. Through the double-ended spline shaft involute spline vice from the turbine's main shaft to the accessory magazine in the various movements. Due to the double spline shaft it transmits a very large amount of power and a high speed, thus requiring a very smooth involute spline pair transmission. In view of this, the high hardness elongated hollow double spline shaft as the object of study, based on its structural characteristics and machining process difficulties, the formulation of a number of process routes and validation, in order to improve the stability of the batch processing of this type of parts.