关键词: 精密钢球传动, 瞬时接触域, 生热率, 摩擦温升

Abstract: Based on the Hertz contact theory, a tooth surface contact model was established forward to analyze the instantaneous contact areas and thermal characteristics of reducing mechanisms for precision ball transmissions. The contact patches among the balls and tooth surfaces of cycloidal groove were analyzed, then the effects of the input shaft speeds and loads on the thermal characteristics of reducing mechanisms were investigated. Instantaneous heat generation rates and instantaneous frictional temperature rises among the balls and tooth surfaces were obtained. The results indicate that the instantaneous contact areas among the balls and tooth surfaces of cycloid groove is a time-varying contact ellipse. The input shaft speeds and loads have visible influences on instantaneous heat generation rates and frictional temperature rises, but the influences of speeds are greater. Instantaneous friction temperature rises are monotonically increasing with the increased speeds under the general speed conditions, but in the low speeds, temperature rises are monotonically decreased and then monotonically increased. The results of the study provide a good foundation for three dimensional thermal mechanical coupling analyses of precision ball transmissions.

Key words: precision ball transmission, instantaneous contact area, heat generation rate, friction temperature rise