How to predict ball screw life?

From its role,the life of ball screw is divided into three types:flaking life,lubrication life and wreck life.Flaking life is generally referred to as ball screw life.

When the ball screw works under axial load,the shaft,nut groove surface and ball surface bear repeated load.After that,the ball screw flak due to material fatigue.The total number of revolutions to the first flaking of the surface is called the ball screw flacking life.There are many deviations in the flaking life,so the ball screw life is defined as a statistical phenomenon below,called the basic rating life.

The basic rated life of the ball screw refers to the total number of revolutions of the ball screw,and 90% of the ball screws can withstand this number of revolutions.The failure is manifested as flaking caused by rolling fatigue of the groove or ball surface.These numbers are valid when a set of ball screws of the same type are run separately under the same conditions.

The basic dynamic load rating Ca is the axial load for which the basic rating life is1000,000 revolutions.Ball Screw's basic rating Life L10 can be estimated using basic bynamic load rating Ca in the following formula.

Ca:Basic dynamic load rating N {kgf}

Fa:Axial load N{kgf}

N:Revolution min-1{rpm}

0:Lead mm

f:Load factor

f=1.0~1.2 (for almost no vibration,no shock condition)

f=1.2~1.5(for slight vibration,shock condition)

f=1.5~3.0(for severe vibration,shock condition)

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