Case Study: Transmission Planetary Assembly

Processes: Conventional powder metallurgy & powder forging

Density: 7.83 g/cm³

Tensile Strength: 1, 310 MPa (190,000 psi) core
1,932 MPa (280,200 psi) carburized

Yield Strength: 1,070 MPa (155,200 psi) core
1,725 MPa (250,200 psi) carburized

Hardness: 38 HRC core
60 HRC carburized

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End Use and Function

The 32-part planetary assembly connects to the input shaft from the engine and supports the planetary pinion gears. This carrier assembly is used in the HF 35 Hybrid Transmission, which is assemble into the hybrid cars—Lincoln MKZ, C-MAX, and Fusion Hybrid vehicles. The carrier assembly must be extra quiet in operation as poor geometry creates a noisy gear which can easily be heard in a hybrid transmission.