Each unit is tempered by induction process to improve ductility and toughness, and increasing impact resistance.
Each forged hub bearing assembly is heat by means of a medium frequency electromagnetic field. The heated part is then quickly quenched to produce a hardened structure.
A grinding stone is used to grind the surfaces of parts to the required dimensional accuracy and precision.
Dimensions such as the outer and inner diameters and the width are ground to micrometer (one-thousandth of amillimeter) precision, as is the groove, a key internal structure formed between the inner and outer rings in
which balls/roller run.
The groove between the outer and inner rings in which the balls run is honed to nanometer (one-thousandth of a micrometer) precision.
Runout Tolerances measurements in the flange
The hub is directly affected by the condition of the bearing. The driver may first notice a noise coming from the wheel of the vehicle when the steering wheel is turned. There will be noticeable end play when the wheel is unloaded. A check using a dial indicator will show an end play greater than 0.100mm. Bearing end play can also affect a wheel speed sensor and cause an intermittent ABS trouble code. If the bearing flange has a runout, that runout will be magnified at the rotor friction surface. A runout of 0.00254mm at the bearing flange could result in a 0.0025mm runout at the rotor friction surface.
A wheel bearing is the most critical component of a braking system. It positions the wheel and rotor to the caliper, the wheel and drum to the backing plate, and controls the input to the wheel speed sensor. As Electronic Stability Control (ESC) braking systems become more complex, the wheel bearing will still be the central component to the system’s operation. With the introduction of the Electronic Wedge Brake (EWB) just around the corner the caliper, wheel speed sensor and chassis controller will become the ABS system. These changes will require greater care in the servicing of the total suspension system.