MSc Manufacturing 1

Bearing defects

A low speed REB test-rig

MSc Manufacturing 2

Simulation of bearing defects

Spark erosion defects

MSc Manufacturing 3

Simulation of bearing defects

Line defects

MSc Manufacturing 4

Simulation of bearing defects

Outer Race Defect: W1 grease

Max amplitude Energy

0 5 10 15 20 25 30 35 400

0.1

0.2

0.3

0.4

0.5

0.6

0.7

SW signature

Peak A

mplit

ude,

Volts

Peak Amplitude: ORD and good bearing, W1 grease

ORD

Good

ORD=0.3344

Good=0.0873

0 5 10 15 20 25 30 35 4010

-8

10-7

10-6

10-5

10-4

SW Signature

Energ

y,

Joule

s

Energy: ORD and good bearing, W1 grease

ORD

Good

ORD=5.2537e-6

Good=3.0248e-7

MSc Manufacturing 5

Simulation of bearing defects

Inner Race Defect: W1 grease

Max amplitude Energy

0 5 10 15 20 25 30 35 400

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

SW signature

Peak A

mplit

ude,

Volts

Peak Amplitude: IRD and good bearing, W1 grease

IRD

Good

IRD=0.2308

Good=0.0873

0 5 10 15 20 25 30 35 4010

-8

10-7

10-6

10-5

SW Signature

Energ

y,

Joule

s

Energy: IRD and good bearing, W1 grease

IRD

Good

IRD=2.6732e-6

Good=3.0248e-7

MSc Manufacturing 6

Simulation of bearing defects

Roller Defect: W1 grease

Max amplitude Energy

0 5 10 15 20 25 30 35 400

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

SW signature

Peak A

mplit

ude,

Volts

Peak Amplitude: RD and good bearing, W1 grease

RD

Good

RD=0.2774

Good=0.0873

0 5 10 15 20 25 30 35 4010

-8

10-7

10-6

10-5

10-4

SW Signature

Energ

y,

Joule

s

Energy: RD and good bearing, W1 grease

RD

Good

RD=4.3742e-6

Good=3.0248e-7

MSc Manufacturing 7

Simulation of bearing defects

Debris: W1 grease

Max amplitude Energy

0 5 10 15 20 25 30 35 400

0.2

0.4

0.6

0.8

1

1.2

1.4

SW signature

Peak A

mplit

ude,

Volts

Peak Amplitude: Debris and good bearing, W1 grease

Debris

Good

Debris=0.5429

Good=0.0873

0 5 10 15 20 25 30 35 4010

-8

10-7

10-6

10-5

10-4

SW Signature

Energ

y,

Joule

s

Energy: Debris and good bearing, W1 grease

Good

Debris

Debris=1.4957e-5

Good=3.0248e-7

MSc Manufacturing 8

Simulation of bearing defects

Discussion: Mechanism of SW formation

• The interaction of mating components under

loading condition would break and deform the

surface asperities which generate SW

• The presence of the localised defects (ORD, IRD, RD

) with higher surface roughness and distortion

generated higher SW amplitude than b/g noise

• ORD: more than one SW signature for every ORD

passage. Each roller had to rub against the full

3mm width of the defect

MSc Manufacturing 9

Simulation of bearing defects

Discussion: Mechanism of SW formation

• IRD & RD: SW were only detected for a certain period of

time. SW generated when the IRD and RD were in the

loading zone

• Grease contamination: SW activities random in time. SW

generated by the crushing activities of the debris particles

at the working interfaces. Debris might slide and rub

against the REB components

MSc Manufacturing 10

Simulation of bearing defects

Discussion: Time domain analysis

• The maximum amplitude and energy of ORD, IRD , RD &

grease contamination fluctuated randomly. Attributed to

the breakage and deformation of the asperities were

inconsistent in nature

• ORD: different orientation the roller struck the ORD.

• IRD: the orientation of the roller struck the IRD and the

variation of the defect position in the loading zone.

• RD: the orientation the defective roller rubbed the outer

and inner race. Also movement of roller in the loading zone

• Grease contamination: could occur from any position and

with varying SW strength

MSc Manufacturing 11

Simulation of bearing defects

All types of defects and debris: W1 grease

Max amplitude Energy

0 5 10 15 20 25 30 35 400

0.2

0.4

0.6

0.8

1

1.2

1.4

SW signature

Peak A

mplit

ude,

Volts

Peak Amplitude: All defects and good bearing, W1 grease

ORD

IRD

RD

Good

Debris

Debris=0.5429

ORD=0.3344

RD=0.2774

IRD=0.2095

Good=0.0873

0 5 10 15 20 25 30 35 4010

-8

10-7

10-6

10-5

10-4

SW Signature

Energ

y,

Joule

s

Energy: Defects and good bearing, W1 grease

ORD

IRD

RD

Good

Debris

Debris=1.4957e-5

ORD=5.2537e-6

RD=4.3742e-6

IRD=2.6732e-6

Good=3.0248e-7

MSc Manufacturing 12

Simulation of bearing defects

Discussion: All types of defects and debris, Time domain

analysis

• Highest max amplitude and energy are associated with

grease contamination due to crushing activities

• ORD recorded the highest max amplitude and energy

among the bearing defects due to the closeness of the

defect to the sensor. Shorter transmission path

• Transmission path play an important role in attenuating

the SW signature