Proper control of distortion has become even more important onnew powertrain designs. To answer the demand for fuelefficientvehicles, modern transmissions are built much lighter, thereforethe components of the transmission exhibit less wall thicknesswhich makes them more sensitive to distortion. Distorted gearcomponents can create noise in the transmission, require post heattreat machining processes and may even create problems duringtransmission assembly. By applying the technology of Low PressureCarburizing (LPC) and High Pressure Gas Quenching (HPGQ), thedistortion caused by heat treatment can be significantly reduced.This technology has been successfully established in serialproduction for many different gear applications. With theintroduction of ‘One Piece Flow heat treatment’, the distortioncontrol can be further enhanced. This ‘One piece Flow – heattreatment’ allows for a rapid case hardening where the componentsare low pressure carburized at high temperatures (1050°C) followedby gas quenching. The components are not treated in conventionalbig batches with multiple layers, but they are treated in smallbatches consisting of one layer only. The quench intensity iscontrolled more precisely to allow for processes which arecustomized individually for each gearcomponent. The singlelayertreatment provides Shomogenous and rapid heating of the components,Shomogenous and rapid carburizing of the components, Shomogenousand precisely controlled gas quenching. All the variations fromlayer to layer are eliminated, which leads to reductions indistortionvariation within the load. In addition, this newtechnology allows strong costssavings for logistics. Themanufacturingline can be completely automated since the parts are1st taken one by one from the soft machining unit, then 2nd heattreated in time with the cycletime of soft machining(“Synchronized heat treatment”) and then 3rd passed down one by oneto the hard machining unit. The paper presents applications forenhanced distortion control when using ‘One Piece Flow heattreatment’.
- Edition:
- 12
- Published:
- 10/01/2012
- Number of Pages:
- 14
- File Size:
- 1 file , 930 KB
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