On-Line Diagnostics of Rear Axle Transmission Errors

This paper describes a methodology suitable for implementation on the production floor, to perform measurement of gear-induced vibrations in assembled axle carriers outside of a vehicle. A dynamic approach to computerized axle testing is described which has resulted in a machine capable of testing more than 100 axle carriers per hour, while exhibiting 95–98 percent correlation with laboratory measurements. The high resolution of measured conjugate gear error of 1 part in 10,000 in terms of angular velocity variations is achieved. The following three major tasks are addressed in the course of the paper: development of an angular sensor; synthesis of a dynamic drive train; configuration of a data processing system. The dynamic concept of the drive train is chosen to measure the conjugate gear error in the most direct possible manner, as torsional oscillations; to ensure adequate transmissibility for both frequency ranges of interest, mesh and boom; and to provide immunity from extraneous inputs. A real-time signal processing technique is developed, employing a peripheral array processor. Along with a decision of acceptability the machine furnishes, whenever needed, a set of supporting indicators to provide for diagnosis of the faults. An efficient method of modeling a drive train for torsional oscillations, and a computer algorithm for rapid and noise-free conjugate gear order analysis, both of general nature, are also described.