ABSTRACT This paper shows the disc-adapter-integrated hub to which the avoidance of braking heat and thermal radiation is applied. Also, it shows that the weight reduction by the integration with the disc adapter as well as the capacity increase on the front axle is achieved in comparison with the conventional wheel end module. This new designed integrated hub has been evaluated by the temperature measurement on the rig and actual vehicle test. In addition, computational analysis with regard to the static strength and fatigue life and the fatigue acceleration test has been performed according to SAE J 1095. INTRODUCTION The disc brake system has been applied on the heavy vehicle for both the purpose of weight reduction and enhancing the brake performance. The conventional disc brake applied to the wheel end module is simply assembled with hub and rotor. It can be easy for this type to be manufactured. However, there are some durability problems with the heat crack because of the difference of temperatures on each side of the rotor caused by the brake heating. ( Fig.1) The splined disc brake system is one of solutions for this thermal damage. This system has the separated rotor and the adapter, the separated rotor which is the friction part of the disc brake, and the adapter which is the mounting part of the wheel hub and disc rotor. The separated rotor and the adapter are assembled with elastic fasteners in order to absorb the distortion of the rotor by the brake heating. ( Fig. 2) Fig.1. Conventional disc rotor and hub(ex.65.4Kg) Fig.2. Splined type disc rotor and hub (ex.62.8kg) Recently truck manufacturers have tried the integration of the hub and the adapter to reduce the weight of rotation parts. The concept of the integrated hub is designed to add the splined rotor mounting parts on the conventional hub that is made up of wheel mounting part and hub bearing part. Therefore the integrated hub reduces the weight of the adapter and lightens the wheel end module which is one of the unsprung mass. ( Fig.3) Design and Validation of the Integrated Wheel Hub2011-01-2170 Published 09/13/2011 EunHo Lee and YongSoo Lee Hyundai-Kia Motors Copyright © 2011 SAE International doi:10.4271/2011-01-2170Downloaded from SAE International by University of Minnesota, Wednesday, August 01, 2018Fig.3. Splined rotor with integrated hub (ex.54.1kg) However, the integrated hub must be designed to avoid the heat damage with regard to the lifetime of hub bearing. This is because the direct mounted rotor on the hub is a heat source when braking, since it produces friction with lining. When the hub unit bearing is exposed to much higher temperature than the heat resisting temperature, the heat will change the properties of the grease that is inside the hub unit bearing. Therefore, the lifetime of the hub unit bearing will be shortened because the lubricating performance will decrease remarkably. The burning and breaking of the hub bearing happened despite the comparatively short mileage on the first designed-integrated hub, because it focused only on the weight reduction and was designed without considering the possible influence of the braking heat. This paper shows the unique integrated hub that the avoidance of braking heat and thermal radiation is applied. Also, it shows that 17% of the weight reduction as well as the 5% capacity increase on the front axle is achieved in comparison with the current system. This designed integrated hub has been evaluated by the temperature measurement test and the fatigue acceleration test according to SAE J 1095 and SAE J 2562.1) 2) BODY 1. THE AVOIDANCE OF BRAKING HEAT 1.1. Design Concept The integrated hub must be designed to avoid the heat damage caused by braking with regard to the durability of hub bearing. 1). Penetrated Radiation Holes The penetrated radiation holes are formed with the same circular interval from the each rotor mounting tooth part to wheel mounting flange. The holes radiate the heate