Light weight design, manufacture and test results of powder metal gear transmissions - (PPT)

摘要

Findings from redesign, building and testing of powder metal (PM) gears in prototype transmissions will be presented. Several transmission rebuild projects have been undertaken during the past 8 years and there has been a lot of knowledge built up in the different aspects of PM gearing. Topics that will be dealt with in this paper is light weight macro design through the unique manufacturing process that PM offers. There are also differences in micro design between steel and PM gears due to the difference in Young's modulus, which will be explained and exemplified. PM gear manufacturing technology will be discussed. There are several manufacturing steps that can be combined that will lead to different performance levels of the PM gears, this will be touched upon and solid fatigue data presented. NVH is increasingly important with electrification of vehicles and PM offers some material inherent advantages due to the porosity and test results from a 6 speed manual transmission will be shown. PM gear wear has also been studied and will be quantified from duty cycle testing in rig as well as from topographic measurements before and after running.