Extreme corrosion or wear in the ball grooves of either the ball nut or ballscrew shaft, or extreme corrosion of the bearing balls, or all of those.
One recent design consisted of a double-start ball thread with two circuits of bearing balls in each ball thread.
The ball groove geometry, deflector cross section, and material are all designed to maximize load capacity in the event that all bearing balls are lost and the deflectors engage the screw shaft in Acme fashion -- thread to thread.
19 bearing ball deep groove with shields on both sides :- skf 608-2z or fag 608-2z
24 bearing ball deep groove with shields on both sides and c3 clearance :- skf 6313-2z-c3 or fag 6313-2z-c3
Bearing Ball Thrust Single Row Flat Seating 40X60X13mm Nos 6
Bearing Ball Thrust 80x105x19mm width straiaht bore (SKF Or Equivalent) Nos 1
In the Four Ball Wear Test (ASTM D 4172), three steel bearing balls
are clamped together and covered with the test fluid, while a rotating fourth ball is pressed against them in sliding contact at various force levels.
To reduce sliding friction between the bearing balls
and planet carrier bolts the rolling or sliding bearings are applied.
Thomson invented and manufactures a complete family of Ball Bushing(R) bearings, 60 Case(R) LinearRace(R) shafts, Thomson Saginaw(R) and IBL ball screws; RoundRail(TM), Smart Rail(R) and ProfileRail(TM) linear guides, systems and controls; Micron True Planetary(R) gearheads; Nyliner(R) engineered polymer bearings and FluoroNyliner(R) bushing bearings; precision bearing balls
, and Thomson Airpax Mechatronics stepper motors, brushless DC motors, and digital linear actuators.
Thomson Precision Ball Company, LLC, Bristol and Unionville, Connecticut, a leading producer of precision bearing balls for Thomson bearing and ball screw products, and those of other manufacturers.
Thomson manufactures Super Smart Ball Bushing* bearings, 60 Case* LinearRace* (shafts), Thomson Saginaw* and IBL* ball screws, RoundRail*, SmartRail* and ProfileRail* linear guides, linear motion systems and controls, Micron True Planetary* gearheads, Nyliner* engineered polymer bearings and precision bearing balls.