航空鼓形花键设计及其不对中接触特性

Design method and its misaligned contact characteristic of aviation crowned spline

针对鼓形花键设计方法不完善、修形量范围无法确定的问题,提出利用花键齿面许用应力与内外花键配合干涉确定鼓形花键鼓形量的范围。以某航空发动机中央传动杆花键为例,开展鼓形花键设计;进而对比研究对中与不对中状态下普通花键和鼓形花键的接触特性。结果表明:对中状态下,普通花键接触应力集中于齿向加载端,而鼓形花键则集中于齿向中部且接触应力增大;不对中状态下,普通花键接触齿对数目显著减小且接触应力显著提高,而鼓形花键的均载性显著且接触应力降低;随着不对中的增大,普通花键因干涉而存在断齿风险,而鼓形花键仍能够啮合但脱开齿对数目增加,接触应力也急剧提高。所确定的鼓形花键修形量范围合理,能够将齿侧间隙、不对中补偿能力、与修形量定量耦合起来,为航空鼓形花键设计、不对中控制、承载能力与寿命提升提供了重要理论参考。

In view of the imperfect design method of the crowned involute spline and the uncertainty of the range of the modification amount,a method of designing the crowned involute spline was proposed by using the allowable stress of the spline tooth surface and the interference of the inner and outer splines to determine the range of the crowned amount of the crowned spline.Taking the spline of a central transmission rod of an aero engine as an example,design of the crowned spline was carried out;and the contact characteristics of the ordinary spline were compared with those of the crowned spline under the alignment and misalignment state respectively.The research results showed that under the aligned condition,ordinary spline contact stress was concentrated on the tooth loading end,while the contact stress of the crowned spline was located in the axial tooth middle and the contact stress increased;in the misalignment state,the number of contact tooth pairs of the ordinary spline significantly reduced and the contact stress significantly increased,while the load-sharing effect of the crowned spline was significantly improved and the contact stress significantly reduced.As the misalignment increased,the ordinary spline had the risk of tooth breakage due to interference,while the crowned spline could still engage but the number of disconnected tooth pairs increased,and the contact stress also increased sharply.The determined range of the crowned spline modification amount was reasonable,and it can quantitatively couple the tooth backlash,misalignment compensation ability,and the modification amount.The research results provide an important theoretical basis for designing aero crowned splines,controlling the misalignment and improving the load-bearing capacity and the wear life.