August 1, 2006

NTN Develops World's First "Tapered Hub Bearings
for Semi-Floating Suspension"

NTN Corporation (NTN) has developed an orbital-formed type tapered hub bearing that acts as a wheel bearing for semi-floating suspension. This has now been adopted for mass production for the rear wheel and is the world's first mass production of an orbital-formed type tapered hub bearing for semi-floating suspension.

The semi-floating suspension that has been adopted for the rear wheel (drive wheel) on many small trucks and commercial vehicles features the wheel hub and axle as a single unit. Either two single-row tapered roller bearings or double-row tapered roller bearings are located between the axle tube and the axle. Although the semi-floating suspension features a simple structure and is lightweight, latest demands have called for improved lightness, ease in installation and reliability.

In this newly developed product, a double-row tapered roller bearing with a flange is press fit in the wheel hub, followed by orbital forming in a structure in which the axle and hub wheel, which are usually a single unit, are separate. This achieves a weight reduction of approximately 6 kilograms per unit. This structure is one in which the outer ring of the bearing is bolted to the axle tube and the axle is fit into the spline of the hub wheel to simplify installation on the vehicle. Furthermore, orbital forming makes it possible to set the ideal preload on the inside of the bearing to achieve an improvement in reliability.

This newly developed product is appropriate for use on full-size vans and SUVs as well as pick-up trucks, with active market development. NTN has already begun mass producing this new product to be used in the DaimlerChrysler Sprinter.

[Features]

1. Lightweight:
   • A hollow axle for a weight reduction of 6 kg/unit (2 hub bearings/unit)
     (comparison with axle as a single unit)
2. Easier to install:
   • Bolting of axle tube and spline fitting of the axle for easier installation
3. Reliable:
   • Setting ideal preload thanks to orbital forming on inner ring of the bearing

[Photograph of external view of orbital formed type tapered hub bearing]

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