An axle with an integrated input planetary stage has been simulated with ParticleWorks to predict the oil flow path in the planetary stage when the machine in which it is mounted faces the changes of slope of the ground. For this reason, a speed law that reproduces the slope variations has been imposed: a first step in which the axle is in an horizontal configuration is followed by the second step in which it is sloped to simulate the uphill configuration, then the downhill condition is the third step followed again by the horizontal position.
The first simulation has been run considering the current housing oil passages geometry and the current level of oil and it has shown that almost all the quantity of oil that arrives in the oil passages reaches the two bearings of the spiral pinion shaft and does not arrive to the planetary stage during the sloped conditions. Thus, a second simulation has been run modifying the oil passages geometry, maintaining the previous oil level: in this case there is a significant increase of oil quantity that reaches the planetary stage and also during the sloped configurations meaning that the optimizations are working properly. In the third and last simulation the oil level has been increased: this simulation has shown that there is a further increase of oil exchange between the oil passages and the planetary stage but the oil quantity that remains in the planetary stage doesn’t change significantly.
With those three simulations it has been possible to improve the lubrication of the planetary stage optimizing only the housing oil passages geometry without increasing the oil level that would have meant increase of temperature and loss of efficiency.