Study On The Tooth Root Bending Stress Of The 42CrMo Quenching And Tempering Gear And Surface Hardening Gear

Gear transmission is widely used in mechanical transmission for the advantage of efficient,compact,reliable. Gear using life plays an important role in the gear transmission. Gear Life and the whole production process were direct affected by the failure of gear tooth, such as tooth fracture,tooth surface abrasion,tooth surface pitting,tooth surface scuffing,and plastic deformation. Tooth fracture is one of the most important factors. The common form of tooth fracture is bending fatigue broken and overload broken. And with the more typical damage is bending fatigue damage. Therefore, gear design calculation process was according to bending fatigue. This paper mainly studies the materials for 42CrMo quenching and Tempering Gear and surface hardening gear bending fatigue properties, and get bending fatigue limit. The main work is that was done in this paper includes:1. The bending fatigue test of 42CrMo quenching and tempering gear and surface hardening gear was down. In this case,QBG-300 microcomputer controlled high-frequency fatigue test machine and double tooth pulse bleaching loading method are adopted. Every level stress cycling life failure was records. Different gear specimens of bend fatigue strength of R-S-N curve obtain from different heat treatment. Gear bending fatigue limit get under the cycle radix 3×106, and the logarithmic fatigue life of test gear was calculation, and examine for experiment data of normal distribution was down.2. Use Visual Basic to write the gear's involute and the transition curve part program. Gear tooth profile could be changed by inputting different tooth number, modulus and gear root fillet radius.3. Use the program written in SolidWorks2008 to create different gear root fillet radius of the involute spur gear.4. Using finite element analysis software—ANSYS9.0, For the root fillet radius is 0.38 of involute spur gear loading with experiment of the same load make use of finite element method. And use GB/T14230-1993 calculation method of stress,when YST=1.0 calculation results and finite element analysis results for the comparative analysis.5. After analyzing the bending Stress for the 0.38 transition curve of involute spur gear stress, further comparison and analysis transition curve fillet radius for 0.30,0.42,0.14and0.472 of the involute spur gear are taken.