Parameswaran R.,PMG Indiana Corporation |
Nigarura S.,PMG Indiana Corporation |
Bird M.,PMG Indiana Corporation |
Scott M.T.,PMG Indiana Corporation |
Gates J.D.,PMG Indiana Corporation
International Journal of Powder Metallurgy (Princeton, New Jersey) | Year: 2012
A study was conducted to establish the correlation of wrought steel axial fatigue to Stroker durability of surface-densified powder metallurgy (PM) races. The roller OWC (one way clutch) was selected based on PMG's experience in the production of < 5 × 10 6 surface-densified outer race cams. The sintered cams were subjected to surface densification on the inner surface. A layer of fully dense material at depths up to 0.5 mm enhanced the fatigue properties of the material in the area subjected to the highest levels of stress. The OWCs with the outer race cams were tested to different levels of torque in order to establish an S-N curve. A stress-based fatigue model was chosen with the maximum principal stress in the material as the stress measure. Given the process conditions for these outer races, minimal plastic deformation was anticipated, justifying the choice of this stress measure. The result shows that areas of high tensile stress exist in the cam hook, at the edge of roller loading, and in the roots of the external spline teeth.