Research On Effect Of Thermal Deformation On Vibration Characteristics Of Gears

Involute is the most commonly used gear flank curve, and itsfeature incurs relativegear pair sliding at the meshing points. The frictionheat generated will cause temperature rise and thermal deformation of thegear flank, thus affecting the transmission performance of the gear pair. Asthe demand for gear transmission accuracy becomes higher, this problem hascaused much concern. Up to now, researches were typically concerned onlyabout the calculation of the temperature field or gear thermal deformation,whereas researches on the interaction between gear thermal deformation andgear pair vibration characteristics were seldom seen. To solve this problem,this thesis combined the two approaches, i.e. calculated the error of toothprofile deformation, and on this basis analyzed the variation rules ofvibration characteristics of gear under the condition of tooth profile thermaldeformation. Specific study content is as follows:Firstly, this paper built up the parameterized analysis model of the gears, andstudied the steady-state temperature field distribution of the gears by finite elementmethod. Some characteristics of the steady-state temperature field were found: thehighest temperature is distributed on the center region of meshing surface, andlocated in shallow surface layer, whereas the rest parts’ temperature is distributedmore evenly. External factors such as rotating speed have great impact on highesttemperature, but little to the whole temperature field.Secondly, profile thermal deformation of involute tooth was calculated by theeven temperature field model based on the mean node temperature and geartemperature field distribution situation. The formula to calculate total profiledeviation, profile form deviation and profile slope deviation were given according tothe national standard, and verified through experiment. As a result the profiledeformation characteristics of involute tooth in the case of isothermal deformationare obtained: the gear shows slope positive error pointing to outside of the body fromaddendum to dedendum.Finally, the formula of nonlinear vibration of gear pairs was established using the lumped parameter method, in which the tooth profile deviation due to thermaldeformation was introduced into a non-linear model in the form of error stimulus.Then the conclusion of the effect of tooth profile thermal deformation on thevibration characteristics of gear pair was obtained after calculating: as the deviationincreases, the response will change from simple harmonic response to subharmonicresponse, but still not to the extent of chaotic movement.This study integrated the gear thermal deformation and vibration characteristicsof gear pair, and will play a positive role on the researches of gear vibration controland correction of the flank shape.