螺旋齿轮与正齿轮的表面致密化

Surface densification of helical and spur gears

过去几十年,用于汽车的粉末冶金零件不断增长,对零件性能的要求也越来越高。汽车用的变速器齿轮的形状复杂,按照齿轮质量要求(DIN,ISO,AGMA等)几何精度很高,按齿面与齿根的耐久性要求力学性能也很高。对于制造复杂形状零件,粉末冶金法对控制成本很有效。通过增加对齿的选择性致密化,在增加很少费用下就能满足精度与力学性能要求。由压制、烧结、碾压致密化及最后热处理组成的工艺路线,可评估用粉末冶金制造的变速器齿轮的可行性。在研究中所用的螺旋齿轮与正齿轮,对致密化及所得到的齿轮的质量与齿根疲劳都进行了试验。

The past decades have seen a continuous growth of the use of PM parts in automotive applications. However, the performance requirements the components must meet are more and more demanding. Transmission gears for automotive applications are complex in shape and require very high geometrical accuracy in terms of gear quality （DIN, ISO, AGMA, etc） and also very high mechanical performance in terms of durability of tooth flank and root. Powder metallurgy is very cost effective for complex shaped parts and by adding a selective densification of the teeth the accuracy and mechanical performance requirements can be met at a very low added cost.A process route consisting of compaction, sintering, surface densification by rolling and finally heat treatment was used to assess the feasibility of producing transmission gears by powder metallurgy. Helical and spur gears were used in the study where the densification as well as the resulting gear quality and tooth root fatigue was tested.