PSI - Issue 57

5

Author name / Structural Integrity Procedia 00 (2019) 000 – 000

Dr.-Ing. D. Jbily et al. / Procedia Structural Integrity 57 (2024) 199–216

203

The surface roughness of the flanks of the test gears was measured before and after shot peening before testing. The measurements were made on 3 teeth of each gear and on the two flanks named A and B of each tooth. The roughness was characterized by white light interferometry using a non-contact 3D surface roughness machine. The measurement results show that Rsk and Rku have the same orders of magnitude while Ra, Rq, Pc and Rz have lower values on the shot peened gears (see Fig. 4).

Fig. 3. Measurement of tooth flank roughness

Fig. 4. Roughness measurement results

3. Gear contact fatigue tests

3.1. Test Rig and test Conditions In order to study the sensitivity of gear flanks to micropitting, contact fatigue tests were carried out on a back-to back gear test rig (91.5 mm) developed by Design Unit Fig. 5. This test rig is based on a recirculating power loop principle, which provides a high level of torque through the tested gears, only consuming a small amount of power to drive them. The test rig is able to test two identical gears with the same ratio and the same loading conditions simultaneously. A photo and schematic diagram of the gear test rig are shown in Fig. 5. Two gearboxes (called A and B) are connected back-to-back by two shafts. In the experiment, the test rig is controlled by software installed on the control computer, to monitor the lubricant temperature, torque, rotational speed and vibration levels. If any of these conditions exceeds or falls below the user defined limits, the system will shut down for safety reasons.