Abstract: Due to the small center distance, the dynamic performance of small modulus gear transmissions was very sensitive to the center distance errors. In addition, the intermediate gears were often designed to rotate at high speed on the fixed shaft, and there were clearances between the gear center hole and the shaft. Therefore, the calculation model of the gear mesh characteristic parameters and time-varying mesh stiffness under the influences of the center distance errors and the shaft hole fit clearances was established, and the influence laws of the two factors mentioned on the mesh stiffness were investigated. The results show that the center distance errors will change the contact degree and meshing stiffness of the gear pairs. The shaft hole clearance causes the actual center distance to fluctuate periodically around the theoretical center distance, which leads to the coexistence of the strengthening and weakening regions of the meshing stiffness in the whole cycle. The influences of center distance errors and shaft hole fit clearances both superimposed and weakened each other in different angle ranges, resulting in the difference in meshing stiffness of each gear tooth, and the risk of inducing greater vibration and different noise.

Key words: small module gear, time-varying meshing stiffness, center distance error, shaft hole fit clearance

摘要： 小模数齿轮传动中心距较小，其动态性能对中心距误差非常敏感，且中间级齿轮常被设计在固定轴上高速旋转，齿轮中心孔与轴之间存在间隙,考虑这些特征，建立了中心距误差与轴孔配合间隙影响下的齿轮啮合特性参数与时变啮合刚度计算模型，研究了二者对啮合刚度的影响规律。研究结果表明：中心距误差会改变齿轮副的重合度与啮合刚度；轴孔配合间隙使实际中心距围绕理论中心距上下周期性波动，导致整个周期内啮合刚度强化区域与弱化区域共存；中心距误差与轴孔配合间隙的影响在不同的转角范围内存在既有相互叠加又有相互削弱的现象，这一现象使得各轮齿的啮合刚度有差异，存在诱发更大振动与不同噪声的风险。

关键词: 小模数齿轮, 时变啮合刚度, 中心距误差, 轴孔配合间隙