PSI - Issue 57

6

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

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

204

Fig. 5. Back-to-back gear test rig 91.5 mm

The test operating conditions are shown in the tables hereafter. For each test, we perform a running-in phase for 2 hours with a torque of 94.1 Nm (25% of nominal load) and a speed of 2250 rpm before applying the nominal torque.

Table 3. Operating conditions

Loading

Pinion torque (Nm)

Pinion speed (rpm)

Time (hours)

Contact stress (MPa) Pinion/wheel

Running-in

94.1

2250 2250

2

977.5/913.4 1945/1817.6

Nominal loading

372.6

Table 4. Lubrication conditions

Lubrication type

Oil injection lubrication Mobilgear 600 XP 150

Designation

Viscosity at 40°C Viscosity at 100°C Lubricant temperature

150 cSt 14.7 cSt

80°C

SKS number (Load stage micropitting test)

10

The test cycle includes stop phases to follow the initiation of micropitting and its evolution on the active flanks. At each stop, photos of the flanks are taken. The criterion for stopping the test is the transformation of the micropitting into widespread macropitting/spalling of the active flanks.

3.2. Initiation and propagation of micropitting All teeth of pinion and gear wheel are numbered to allow clear identification of micropitting locations. Photographs of the gear tooth flanks are taken, showing the initial state and after different loading cycles, enabling observation of the evolution of the flanks damage. This procedure was applied to all the tests performed. An example of test results is shown in Fig. 6.