US Patent:
20090204343, Aug 13, 2009
Inventors:
Jose M. Lopez - Brighton MI, US
David C. Pomerville - Brighton MI, US
Scott R. Kloess - Rochester Hills MI, US
Robert S. Brines - White Lake MI, US
Marc J. Tahnoose - West Bloomfield MI, US
Darrin S. Mallard - Oxford MI, US
Assignee:
GM GLOBAL TECHNOLOGY OPERATIONS, INC. - Detroit MI
International Classification:
G06F 17/18
G01H 17/00
Abstract:
A method of determining steering rack rattle propensity of a rack and pinion steering assembly may comprise: simultaneously recording audio, and measuring acceleration of a rack, and right and left side tie-rod end loads; identifying rack rattle events from the audio recording; determining common characteristics of the measured rack acceleration and tie-rod end loads during the identified rack rattle events; creating a rack rattle index level; applying a predetermined force profile to a test rack and pinion steering assembly; measuring a test acceleration on the test rack and pinion steering assembly; calculating a test RMS level in a test frequency range using a test time constant; determining a rack rattle index value from the calculated test RMS level; and comparing the rack rattle index value to the rack rattle index level.