Study on Load Bearing Capacity of Gears in Special Environment

研究了不同渗层深度的渗层齿轮在低温(-60ﾟC)下的冲击疲劳强度和弯曲疲劳强度。试验采用齿轮冲击试验机和带冷却室的液压加载式齿轮弯曲疲劳试验机。较好地阐明了渗层淬火齿轮在室温和低温下的冲击疲劳强度和弯曲疲劳强度，以及渗层深度对其强度的影响，并研究了真空条件下齿轮的摩擦磨损特性。研制了一种带真空室的动力循环式齿轮试验机，可测量不同运行条件下接触齿面间的摩擦系数以及轮齿和轮轴的温度。利用齿轮试验机对S45C、MoS2涂层的SUS440C、杜拉肯和尼龙四种齿轮在空气和真空环境下进行了运转试验，并测定了…与S45C、MoS2涂层齿轮之间的摩擦系数在接触齿面上，测量了轮齿的磨损和轮齿、轴等部位的温度变化。在此基础上，在很大程度上阐明了齿轮在真空中的摩擦磨损特性。硬齿面齿轮在低温(-60ﾟC)下的弯曲疲劳强度大于室温下的弯曲疲劳强度，但在低温下的冲击强度较小。渗层硬化齿轮在低温和室温下的弯曲疲劳强度存在最佳渗层深度。冲击强度随着壳层深度的增加而降低。S45C齿轮在真空中的摩擦系数大于空气中的摩擦系数，而MoS_2涂层的SUS440C、DURACON和尼龙齿轮在真空中的摩擦系数与空气中的摩擦系数相当，从而阐明了齿轮在低温和真空中的承载能力，为特殊环境下的齿轮设计提供了有用的数据。较少

The impact and bending fatigue strengths of case-hardened gears with various case depths at low temperature (-60ﾟC) were investigated. For this experiment were used gear impact testing equipment and a gear bending fatigue testing machine of hydraulic loading type with a cooling chamber. The impact and bending fatigue strength of case hardened gears at room and low temperature, and the effects of case depths on these strengths were clarified considerably.The friction and wear characteristics of gears in vacuum were also investigated. The gear testing machine of power circulating type with a vacuum chamber was developed, in which the coefficient of friction between the contacting tooth surfaces, and the temperatures of the gear teeth and the shaft can be measured under various running conditions. The running tests for S45C, MoS_2 coated SUS440C, Duracon and Nylon gears were carried out in air and vacuum environment by using the gear testing machine, and the coefficient of friction betwee … More n the contacting tooth surfaces, the wear of the gear teeth and temperature changes of the gear teeth, the shaft, etc. were measured. On the basis of these results, the friction and wear characteristics of gears in vacuum were clarified to a considerable extent.The main results obtained from this investigation are summarized as follows.1. The bending fatigue strength of case-hardened gears at low temperature (- 60ﾟC) is larger than that at room temperature, but the impact strength at low temperature is smaller.2. The optimum case depth exists for the bending fatigue strength of case-hardened gears at low and room temperatures. The impact strength decreased with an increasing case depth.3. The coefficient of friction of S45C gears in vacuum is larger that in air, but those of MoS_2 coated SUS440C, Duracon and Nylon gears in vacuum are almost equal to those in air.Thus the load bearing capacity of gears at low temperature and in vacuum was clarified, and the useful data for the design of gears in special environment were obtained from this investigation. Less