大模数齿轮采用中频沿齿面淬火,淬火后其淬硬层仅仅分布在齿的接触表面上,而在齿的根部终断,如图-a所示。这样在淬火终断的根部,易形成拉伸残余应力。这些应力降低了齿根的弯曲疲劳强度,对齿轮的使用不利。采用中频沿齿沟淬火,淬火后其淬硬层是沿整个齿沟的轮廊均匀连续 Large modulus gear with medium frequency along the tooth surface quenching, hardened layer after quenching only distributed in the contact surface of the tooth, but in the tooth root termination, as shown in Figure-a. This quenching end of the root, easy to form tensile residual stress. These stresses reduce the bending fatigue strength of the tooth root, which is detrimental to the use of the gear. The use of IF along the tooth groove quenching, hardened layer after quenching is continuous along the entire gear groove vestibule continuous