| The curve-face gear compound transmission is a new form of gear transmission.It has both the movement characteristics of the face cam-roller mechanism and the curve-face gear pair,can transmit the compound motion of variable transmission ratio movement and axial movement between the intersecting axes.And it can replace the traditional complex combination mechanism and has the characteristics of simple structure and high reliability,which has potential widely application prospects in engineering machinery,car manufacturer and other fields.This subject is funded by the National Natural Science Foundation-funded project "Design Theory and Experimental Research on Intersecting Shaft Variable Transmission Ratio Composite Transmission Gear Pairs"(No.51675060).This paper mainly explores the contact fatigue life calculation method applicable to the compound transmission of curve-face gear,and establishes an experimental bench to verify it.So the following research has been carried out in this article:Based on the gear meshing principle,the motion model of curve-face gear composite transmission was established.The meshing principle on composite transmission of curve-face gear was explained.The pitch curve equation of curve-face gear pair was obtained.The tooth surface equation and tooth surface contact equation of curve-face gear pair were derived.The fatigue pitting mechanism of curve-face gear was analyzed,and the influencing factors of pitting fatigue of the tooth surface were discussed.According to the gear fatigue test methods with different materials and the material properties of curve-face gear,the material S-N curves of curve-face gear under different experimental conditions were discussed.The several theories such as linear damage Miner’s law,bilinear damage Miner’s law which can be applicable to the fatigue life of curve-face gear were analyzed comparatively.The strain-life curve of curve-face gear was established,and the formula for calculating the crack initiation life of curve-face gear was obtained.Using the finite element analysis software and stress intensity factor theory,the contact stress at the crack tip of curve-face gear and the stress intensity factors under different influencing factors were calculated.The calculation formula of the crack growth life of curve-face gear was deduced.According to the mechanical principle and knowledge of gear geometry,the meshing process of curve-face gear compound transmission was analyzed.The dangerous position of gear contact fatigue was determined.The derivation of calculation formula of the external load on curve-face gear was completed,and the influence of the gear pair basic structural parameters on the external load was discussed.Using Hertz contact theory,the contact stress calculation formula of curve-face gear compound transmission was derived.The contact stress changing law of different teeth in the half-cycle and the position of maximum tooth surface contact stress of curve-face gear were obtained.The contact fatigue life of curve-face gear was analyzed and calculated.Combining ADAMS,ANSYS Workbench and n Code simulation analysis software,the contact force load spectrum of curve-face gear compound transmission was obtained.The surface contact stress of five teeth on half-cycle of curve-face gear was calculated.The contact fatigue life simulation of curve-face gear five teeth was completed.The most dangerous tooth and fatigue life value of curve-face gear was determined.Combining with the modern gear fatigue test method,the fatigue test method and process of curve-face gear compound transmission are designed.A dynamic operation experimental bench for curve-face gear compound transmission was built.The curve-face gear pair counter-roll test was conducted.The dynamic input torque and axial displacement of gear pairs with different structural parameters was measured.The post-processing data about the most dangerous tooth fatigue life of curve-face gear with different loads and parameters was obtained.The simulation,experimental and theoretical values were compared to verify the correctness of the contact fatigue prediction method for the compound transmission of curve-face gear. |
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