﻿ Options for gyroscopic moment

# MESYS Calculation Software

 Options for gyroscopic moment

In case of different directions of forces on inner and outer ring contact, the gyroscopic moment on the ball will affect the load distribution. For high speed ball bearings often “outer race control” is assumed which means that spinning speed at outer race contact is zero. The available options are:

“Gyroscopic moment is not considered”:  This is the same behavior than older versions of the software. No gyroscopic moment is considered and spinning speeds are calculated by Coulomb friction.

“Gyroscopic moment based on outer race control”: The ball rotation vector is calculated assuming no spinning at outer race contact. The gyroscopic moment is only causing a friction force at outer race contact.

“Gyroscopic moment based on outer race control, distributed force”: The ball rotation vector is calculated assuming no spinning at outer race contact. The gyroscopic moment is causing a friction force at inner and outer race contact. The friction forces at each contact are proportional to normal force.

“Gyroscopic moment based on inner race control”: The ball rotation vector is calculated assuming no spinning at inner race contact. The gyroscopic moment is only causing a friction force at inner race contact.

“Gyroscopic moment based on inner race control, distributed force”: The ball rotation vector is calculated assuming no spinning at inner race contact. The gyroscopic moment is causing a friction force at inner and outer race contact. The friction forces at each contact are proportional to normal force.

"Gyroscopic moment based on mixed control": Dependent on the loading for each ball the rotation vector of the ball is calculated based on inner or outer race control assumption. The gyroscopic moment is causing a friction force at inner and outer race contact. The friction forces at each contact are proportional to normal force.

“Gyroscopic moment based on friction”: On each iteration for ball equilibrium the frictional forces based on Coulomb friction are calculated in the contact ellipses. The ball rotation vector is based on this calculation. The resulting gyroscopic moments is distributed on both contacts proportionally to the normal loads. This options leads to much longer calculation time and it can lead to convergence problems if not all balls are loaded.

For high speed ball bearing usually “outer race control” is assumed, this limits the selection to two options only. For low speed the gyroscopic has usually only very little influence and can be ignored.

For three-point bearings and four-point bearings the options based on outer ring, inner ring or mixed control can only be used on two point contact. In case of more contact points the gyroscopic moment is set to zero and a warning is shown.