The Voith FlexPad Roll End Hub (REH) design greatly increases hub body operational life through a significant reduction in wear.
In steel mills work rolls are changed regularly. This requires some clearance between roll end hubs (REH) and work roll ends. The clearance leads to wear and continuously growing play, and finally to expensive downtime and re-machining of roll end hub bodies. Voith has solved this problem by eliminating all metal to metal contact in REH-bodies. With selective load application and load, distribution wear is evenly transferred into the FlexPad wear plates that are replaced according to scheduled maintenance cycles. FlexPad wear plate attachment bolts are located in a low-stress area of the hub. Compared to conventional REHs FlexPad prevents unscheduled downtime due to bolt breakages.
Functional principle
With conventional REHs clearance between REHs and work roll ends leads to line contact and thus (load concentration) on the REH body via wear plates, and resultingly causes heavy wear of the hub contact surface.
FlexPad REHs provide for area contact with roll necks via elastic flexibility of the FlexPads. The line contact is transformed into area contact and at a reduced force level. Thereby, the stress level on localized hot spots is significantly decreased. This prevents overloading of the hub and reduces wear.
Benefits
Lifetime of REH several times longer compared to conventional design
Failure-free operation due to avoidance of highly loaded bolt connections
No expensive rework on REH body
Reduction of dynamic effects in the whole driveline due to the damping character of the Flex–layer
Constant low operating clearance
Reduction of the operating cost
Voith
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