Harmonic drives are the core components to enable movement in industrial robots. Unfortunately, the deformation of flexspline causes obvious partial axial load on gear engagement. This synthetic error leads to a series of additional problems, such as the deterioration of transmission quality, and the reduction of both precision and fatigue life. This study focuses on a harmonic drive with a double circular-arc tooth profile. A coordinate transformation is carried out based on the kinematics of harmonic drives. On this basis, the conjugate tooth profile of a circular spline is derived. A simulation model is developed based on the motion relationship for harmonic transmission. The effect of inhomogeneity of the load distribution on the surface of the gear teeth was investigated using the partial axial-load index. The effect of different factors on the partial axial load is analyzed. To reduce the effect of partial axial load of flexspline, we select a suitable material and wall thickness. For a certain practical range, both tooth width and chamfering of the flexspline teeth help reduce the partial axial load and increase the flexspline length. These conclusions enable improvements of future designs of reliable flexspline.

谐波驱动器是实现工业机器人运动的核心组件。不幸的是，柔性花键的变形会在齿轮啮合时引起明显的部分轴向载荷。这种综合误差会导致一系列其他问题，例如传输质量的下降以及精度和疲劳寿命的降低。这项研究的重点是具有双圆弧齿轮廓的谐波传动。基于谐波驱动器的运动学进行坐标变换。在此基础上，得出了圆形花键的共轭齿形。基于运动关系建立了谐波传递仿真模型。使用部分轴向载荷指数研究了载荷分布不均匀对齿轮齿表面的影响。分析了不同因素对部分轴向载荷的影响。为了减少柔性花键的局部轴向载荷的影响，我们选择合适的材料和壁厚。在一定的实用范围内，柔性花键齿的齿宽和倒角都有助于减小部分轴向载荷并增加柔性花键的长度。这些结论使可靠的柔性花键的未来设计得以改进。