Method and apparatus for reducing vibrations transmitted to a vehicle from a wheel unit

Abstract

Vibrations generated by the wheel units of a vehicle are reduced by a low pulsating operation that optimally simulates actual vehicle operating conditions. For this purpose the mass moment of inertia of the wheel unit and of rotating components such as the hub and the brake disc are taken into account. The wheel unit is rotatably mounted on a balancing spindle ( 2 ) in a measuring apparatus to determine the mass and angular location of balancing weights ( 31 ). The vibrations are measured at a speed that corresponds to a typical travel speed of a vehicle. A loading mechanism including a roller shoe ( 20 ) applies a force to the tire tread surface through a spring damping ( 14, 15 ) to optimally simulate the conditions of a roadway. The roller shoe ( 20 ) has rollers ( 13 ) with sections of larger and smaller diameters so that neighboring rollers intermesh. The combined masses of the rollers, as reduced to the roller radius d w , corresponds to the rotational mass of the vehicle wheel as reduced to the tread radius (d R ). It is also possible to disengage the contact force from the tread surface for dynamically balancing the wheel unit under load-free conditions. Thus, wheel-balancing steps under loaded and load free conditions can be done on one machine.