Research On Calculation And Measurement Of Tooth Surface Contact Temperature Of Spur Gear

Gear is a mechanical transmission part which uses the friction of tooth surface to transmit motion and power.Most of the mechanical energy consumed by tooth friction is converted into internal energy,which causes the tooth surface contact temperature to rise.Higher contact temperature is the main cause of tooth surface scuffing,which affects the transmission performance of gear and even causes gear failure.The calculation and measurement of tooth surface contact temperature and the study of the factors affecting the tooth surface contact temperature can provide theoretical basis for the control of tooth surface contact temperature.In this paper,the single degree of freedom spur gear is taken as the research object,and the tooth surface contact temperature under four different lubrication conditions is calculated theoretically,and the correctness of the theoretical results is verified by experimental research.The specific research contents are as follows:Based on Blok flash temperature theory and Hertzian contact theory,the calculation formulas of tooth surface contact temperature under four states of elastohydrodynamic lubrication,mixed lubrication,boundary lubrication and dry friction are derived,and the variation laws of tooth surface friction coefficient along the meshing line under different working conditions are calculated and analyzed.Considering the two states of elastohydrodynamic lubrication and dry friction,the distribution laws of tooth surface contact temperature along the meshing line are calculated theoretically under different rotating speed,torque and backlash conditions.With the help of tooth surface contact temperature measurement experimental platform,experimental measurement research is carried out,and the theoretical calculation results and experimental results are compared and analyzed.It is found that the agreement between the two is good,which shows the correctness and effectiveness of the theoretical calculation method in this paper It is found that different working conditions of the system have an important influence on the change of the tooth surface contact temperature along the meshing line.Considering four lubrication states,the variation laws of tooth surface contact temperature along the meshing line are calculated and analyzed under the changes of rotating speed,torque,backlash and lubricant viscosity parameters.In order to obtain the influence of coupling characteristics of different parameters on the tooth surface contact temperature,the change cloud diagram of tooth surface contact temperature on the coupling plane of different parameters is calculated and studied.In order to obtain the influence law of gear load distribution on the tooth surface contact temperature,the cloud diagram of temperature variation on coupling plane with tooth backlash is calculated and studied.It is found that the tooth surface contact temperature in the coupled plane with backlash appears widely jumps when considers the load distribution.Because the load suddenly increases when the double tooth meshing enters the single tooth meshing,and suddenly decreases when the single tooth meshing enters the double tooth meshing,which causes the two gears to impact,resulting in jumps of the tooth surface contact temperature.Considering the influence of temperature on meshing stiffness and tooth deformation,the expressions of dynamic parameters are established.The change curves of each parameter and the contact temperature of tooth surface along the meshing line are obtained by numerical calculation,and influences of tooth surface contact temperature on time-varying meshing stiffness,gear tooth deformation,lubricant viscosity,backlash and minimum oil film thickness are analyzed.