Securing the Supply Chain for Gear Noise – Developing Tolerances for Roll Testing
Dr. Christof Gorgels
Summary
Particularly in vehicles with an electric drivetrain, the noise behavior of the overall transmission and thus also that of the individual gears has become significantly more important. This makes the noise behavior of each individual gear an important quality criterion. At the same time, all gearboxes are undergoing a 100% functional and noise test after assembly on the end-of-line test bench. Noisy gearboxes will be rejected and scrapped, resulting in high scrap costs.
The single flank rolling test is a way of determining the noise behavior of each individual gear directly after production. In contrast to the geometric characteristics, however, there are often no tolerances on the drawings - these must first be developed. It is important to achieve a good correlation with the tolerance limits of the end-of-line test bench. In this article, a procedure is developed and presented on how a good correlation to the end-of-line test bench can be established. Based on this, a method is shown how tolerances for the single flank rolling test of each individual gear can be derived.
The first aim is to identify the noisy gears and thus ensure that they do not enter the value chain as good parts. In addition, production problems can be detected quickly and rectified promptly without realizing high reject rates. The second goal is to assemble only good gear boxes and thus significantly reduce the reject rate in final assembly.