iso r281 bearings l10 calculation
TRANSCRIPT
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Determining the Main Bearing
Presented by Brian KhalighiVice President, Engineering
The Robbins Company
Standard Indication of Load Cases for Calculation
of Rating Life (L10) of TBM Main Bearings
Life on a TBM
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Introduction
Outline
OUTLINE
e n on o a ng ys em Rating Life Equation Cutterhead Speed Equation Summary of Main Bearing Loads Definition of TBM Main Bearing
Safety Factor Typical Bearing Load Assumptions
by TBM Type Conclusions
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Standardized method of indicating main
bearing load assumptions
Introduction
INTRODUCTION
ear ng ves o ere y var ousmanufacturers
Provides guidance for evaluation TBM types discussed:
Gripper Single shield and double shield (SS, DS) Earth pressure balance (EPB) Slurry (STBM)
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About Rating Life (L 10)
About Rating Life (L 10)
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DEFINITION
Definition of Rating Life ( L10 )
Defined in ISO recommendation R281:
The rating life of a sufficiently large number of identical bearings is expressed by the number of revolutions (or number of hours at constant speed) reached or exceeded by 90% of this
bearing group before the first signs of material fatigue appear.
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The Rating Life ( L10 ) Equation
EQUATION
THE RATING LIFE (L10 ) EQUATION
L10 = (C/P) k
L10: rating life in [10 6 revolutions] C: dynamic load bearing capacity
of the bearing in [kN] P: applied load in [kN] K: for roller bearings = 10/3
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Cutterhead SpeedCUTTERHEAD SPEED
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TBM Main Bearing Safety Factor
SAFETY FACTORS
The safety factor of a TBM mainbearing is defined as the relationbetween calculated bearing L 10lifetime in hours, and the
anticipated cutterhead operationtime for the project
For used bearings, the remaininglifetime should be considered
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TYPICAL BEARING LOAD ASSUMPTIONS
Typical Bearing LoadAssumptions as Used in the
Industry
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Hard Rock TBM (Gripper, SS, DS)
TYPICAL BEARING LOAD ASSUMPTIONS
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Remarks
TYPICAL BEARING LOAD ASSUMPTIONS
CH: e cu er ea rus s e ne as o a o sc cu ers x sccutter load capacity
Fr: the operational radial load F r (resulting from steering loads) is definedas 2 x disc cutter load capacity
The anticipated cutterhead torque T c is only required in case a gearcalculation should be performed
In load cases LC I and LC II, the dynamic roller pressure allowable must notbe exceeded
In load cases LC III, the static roller pressure allowable may not beexceeded
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QUESTIONS
QUESTIONS?