A METHOD FOR MESUARING CREEP GROAN BASED ON BRAKE INERTIAL DINAMOMETER 2005-01-4126

Disc brake noise and vibration control in vehicle interiors has received significant attention in the last years. Creep Groan is a kind of brake system low frequency noise that usually appears in low velocity situation, where there is a transition from static to dynamic condition under brake disc low pressure. The usual method for measuring the creep groan is based on a subjective test pilot evaluation realized on different ramp inclinations. This method, which is realized in the final vehicle, is not very precise and can generate different results associated to breaking noise for different pilots. This work proposes a method for creep groan measuring, which can reduce subjective interpretation throughout the generation of graphics and tables results. To compare the results, final vehicle and laboratory, i.e. inertial brake dynamometer tests were realized. In the vehicle tests an association was proposed between creep groan vibration intensity and the grades established by the test pilot. An accelerometer was installed in the caliper brake system to capture the vibration intensity. For the laboratory tests, velocity and torque were carefully adjusted to create the creep groan effect. The results show that the method proposed can be applied as an useful mechanism to reduce the number of final vehicle tests, throughout the pre-selection of potential brake friction material. The work was developed in a Brazilian brake lining manufacturer.