Analysis of Loads Applied to Wheels of Heavy Vehicles and Study on Loosening of Hub Bolts and Nuts

Heavy vehicles such as construction machinery generally require a large traction force. For this reason, axle components are equipped with a final reduction gear to provide a structure that can generate a large traction force. Basic analysis of vertical load, horizontal load (traction force), centrifugal force, and torsional torque applied to the wheels of heavy vehicles such as construction machinery and industrial vehicles, as well as actual working load analysis during actual operations, were conducted and compiled into a load analysis diagram. The loosening tendency of wheel bolts and nuts that fasten the wheel under actual working load was measured, and the loosening analysis method was presented. The causes of wheel fall-off accidents in heavy trucks, which have recently become a problem, were examined. Wheel bolts are generally tightened by the calibrated wrench method using a torque wrench. The method is susceptible to variations in friction coefficient and tightening torque, and human error affects the tightening torque. Even if the tightening torque (initial clamping force) is insufficient, effective loosening prevention is considered necessary to prevent serious accidents such as wheels falling off. In forklifts, the number of hub bolts is limited due to space limitations, so hub nuts have a spherical or conical alignment structure that allows each nut and bolt to absorb the drive torque and slippage of the bearing surface. In wheel loaders, for example, there is space to install hub bolts, and the clamping force of the bolt sustained slippage of the bearing surface to prevent loosening and fatigue”