Second, the planet gear bearings need to play an active part in torque transfer. Planetary systems split the torque insight from the sun gear amongst the planet gears, which in turn transfer torque to a world carrier linked to the gearbox output. The bearings that support the Helical Gearbox planets on the carrier have to bear the entire brunt of that torque transfer.
Or, in acute cases, they may select angular contact or tapered roller bearings, both of which are designed to withstand axial loads.
In planetary gearboxes, however, it’s a lot more difficult to create around these axial forces for two related reasons. 1st, there is typically hardly any room in a planetary gearbox to include the type of bulky bearings that may tolerate high axial forces.
The presence of axial forces makes things completely different for the bearings that support helical gears. But it is important to make a distinction between fixed-axis and planetary gearboxes. In fixed-axis gearboxes, the excess axial forces total little more than an inconvenience. Gearbox designers will often upsize the bearings to support the additional forces.
Since they don’t need to withstand any axial forces, spur gear bearings play just a supporting part in the functioning of the gearbox. The bearings should just support the rotating gear shafts, but they do not play an active role in torque transfer.
Helical Gears Place Greater Demand on Bearings