A method of repairing array substrate of display panel includes the following steps. Each driving wheel is provided with a respective hub motor having a stator mounted to the vehicle and a rotor directly connected to the driving wheel. This arrangement provides improved shielding efficiency. The guide has an exterior surface on which a plurality of retention members are configured. A silica-modified-Alumina catalyst support of the present invention maintains the desirable properties of alumina and exhibits higher resistance to acid than unmodified alumina. The spindle nut provides more contact surface area with the underlying wear washer, reducing cyclic wear, increasing product life, reliability and security.