Understanding Free-rock
• Freerock is defined as the tilting of a pulley bearing assembly
under load in axial direction, while the inner ring of the bearing
is fixed to the bearing seat. The point of load (radius) and the
load itself are specified for each pulley bearing assembly
separately.
Why a bearing has Freerock?
• Radial clearance in the bearing
• Inner raceway radius is slightly larger than the ball radius
• Outer raceway radius is slightly larger than the ball radius
• Free rock can be limited to a degree, however this involves
reducing radial clearance and making the raceways conform
more to the ball. Both of which increase heat generation and
contact stresses.
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Parts affected 38545, 38579, 38599, 38617, 38635, 38636, 38639