An experimental investigation was performed in this study to quantify the influence of gear position errors and misalignments on the loaded static transmission error of a hypoid gear pair. A test machine was designed and procured for this purpose to allow operation of a hypoid gear pair under a given constant torque and at a very low rotational speed. The test set-up incorporated a capability to induce any type of misalignment at any user defined magnitude, including pinion (H), gear (G), shaft off-set (V) and shaft angle (γ) errors, independent of each other in a tightly controlled manner. An encoder-based transmission error measurement system incorporated with the test machine consisted of two high-precision angular optical encoders and a special-purpose analyzer to obtain the transmission error in both time and frequency domains.
The test matrix considered in this study included all four types of misalignments at various magnitudes, drive and coast side conditions as well as a typical range of input torque. A 4.1 ratio hypoid gear pair from an automotive axle application was used as the example system. The test results were presented in the form of the variation of the first three harmonic amplitudes of the transmission error as a function of torque and error magnitudes. It was shown the each misalignment impacts the transmission error in different levels. The drive and coast side transmission error measurements were shown to differ as well. A nearly “V-shaped” dependence of the first harmonic amplitude of the transmission error to the torque transmitted was also documented regardless of the error type and magnitude applied to the gear pair.