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Roller Bearing WearEA 101 Training
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Roller Bearing Wear
� Every bearing wears differently
� Thousands of different types and sizes
� Key elements to analyzing bearings
� Must be trended
© D
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Commitment to Excellence
Snap ring groove
Inner race
Inner ring
Seal/shieldgroove & notch
Ball
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Inner race
Cage
Outer race
Outer ring
Bore
Inner ringface
Outer ring
face
Outsidediameter
Rolling Element Bearings
For each shaft revolution:
4.6 balls will pass an outer race defect
The ball will make 2.02 revolutions
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Commitment to Excellence
The ball will make 2.02 revolutions
7.4 balls will pass an inner race defect
The cage will make 0.38 revolutions
Bearing Tones in Spectrum
Non-Synchronous Frequencies
100
110
120
VdB
1X
3.1X
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0 1 2 3 4 5 6
60
70
80
90
ORDERS
4X3X
2X 6.2X
Bearing Tone Sidebands
110
120
VdB Bearing Tone
Sidebands spaced at FTF
140
130
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0 1 2 3 4 5 6
60
70
80
100
ORDERS
90
The 9 Stages of Bearing Wear©
DL
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Commitment to Excellence
100
110
120VdB
Machine Without Bearing Problems
Progression of Bearing Faults
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Commitment to Excellence
0 2 4 6
60
70
80
90
1 3 5
Orders
100
110
120VdB
Machine Without Bearing Problems
Progression of Bearing Faults
Stage 1 – Ultrasonic
No indication in Low Frequency
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Commitment to Excellence
0 2 4 6
60
70
80
90
100
1 3 5
Orders
100
110
120VdB
Machine Without Bearing Problems
Progression of Bearing Faults
Stage 2 – High Frequency
No indication in Low Frequency
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Commitment to Excellence
0 2 4 6
60
70
80
90
100
1 3 5
Orders
100
110
120VdB
Slight Bearing Tone at 3.1X
Progression of Bearing Faults
Stage 3 – 1st indication in Low Frequency
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0 2 4 6
60
70
80
90
100
1 3 5
Orders
100
110
120VdB
Bearing Defect Getting Worse
Progression of Bearing Faults
Stage 3
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0 2 4 6
60
70
80
90
1 3 5
Orders
100
110
120VdB
As Bearing Worsens, 2nd Harmonic Rises
Progression of Bearing Faults
Stage 4
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0 2 4 6
60
70
80
90
100
1 3 5
Orders
100
110
120VdB
Looseness also Brings Up 1X Harmonics
Progression of Bearing Faults
Stage 5
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Commitment to Excellence
0 2 4 6
60
70
80
90
100
1 3 5
Orders
100
110
120VdB
1X Sidebands Around the Bearing Tone
-1X
Progression of Bearing Faults
Stage 6
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0 2 4 6
60
70
80
90
100
1 3 5
Orders
+1X
+2X
-1X
-2X
100
110
120VdB
Haystack in Noise Floor as Wear Progresses
Progression of Bearing Faults
Stage 7
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0 2 4 6
60
70
80
90
1 3 5
Orders
100
110
120VdB
Entire Noise Floor Rises in Advanced Stages
Progression of Bearing Faults
Stage 8
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Commitment to Excellence
0 2 4 6
60
70
80
90
1 3 5
Orders
100
110
120VdB
Machine Failure
Progression of Bearing Faults
Stage 9 – Too late
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Commitment to Excellence
0 2 4 6
60
70
80
90
1 3 5
Orders
