milan soukup, skg railway: making heavy haul heavier: exploring technical advancements towards...

Making heavy haul heavier Exploring technical advancements towards increased wheel bearing reliability

Presented to: ARA Heavy Haul Rail 2013 Conference

Presented by Milan Soukup

August 1, 2013

© SKF Group 2 August 2013 Slide 2

Agenda

1. SKF introduction

2. Drivers for higher reliability in heavy haul

3. Reliability approach in passenger versus freight

4. Technical advancements extending wheel bearing service life

5. Principles of Condition Monitoring in Heavy Haul Rail

6. Summary

SKF Group

1

© SKF Group 2 August 2013 Slide 4 2 August, 2013 Slide 4

SKF – a truly global company

• Established 1907

• Sales 2012 AUD 10 345 million

• Employees 46,775

• Production sites around 140 in 28 countries

• SKF presence in over 130 countries

• Distributors/dealers 15,000 locations

• Global certificates ISO 14001

OHSAS 18001 certification


SKF in Rail

• Axleboxes

• Axle bearings

• Axletronic

• AMPEP – High performance

plain bearing

• Axletronic systems

• Sensors

• IMxR monitoring system

• Multilog

• Gearbox bearings

• Motor bearings

• Bearing design & consultancy

• Training

• Bearing refurbishing

• Bearing investigation

• Bearing exchange

• Bearing re-lubrication

• Bearing Condition Monitoring

OTHER RAILWAY SERVICES

• Axlebox overhaul

• Suspension Tubes overhaul

• Drive system bearings

overhaul BOGIE

• Slewing bearings

• Suspension tubes

DRIVE SYSTEMS

• Wheel flange lubrication

systems

CONDITION MONITORING

OTHER APPLICATIONS

• Articulation

joints

SERVICES PRODUCTS

OTHER APPLICATIONS

2 Drivers for higher reliability in heavy haul


Drivers for higher reliability in heavy haul

Main issues:

Unplanned stops – profit loss in operation

Accidents, damaged asset or even human health and life – cost of

repair and other related cost

Maintenance cost

COST OF OWNERSHIP


Specific heavy haul conditions in Australia

The most extreme conditions in the bearing world

Iron ore cars in Western Australia currently run the highest axle

loads of anywhere in the world, 40 tonnes.

Each failure causes extreme profit losses due to single line

arrangement

Class K, Class G & Short Class G operated with axle loads certainly

more than what they were designed for

Industry has expressed desire to move to even higher axle loads, in

line with plans of shipping higher tonnages.

Industry has expressed desire for higher reliability and longer service

intervals


Operation conditions in Heavy Haul – application example

CTBU BT2-8609

Iron ore wagons, with 3 piece AAR style

bogies

170,000km/yr in ambient temperatures

of 0-50deg C in Western Australia

• Axle load 38 tonnes

• Speed 75 km/hr

• CTBU units in

service

7,000 (60,000

total)



CTBU BT2-8606C

Iron ore wagons, with 3 piece AAR

style bogies

190,000km/yr in ambient

temperatures of 0-50deg C in

Western Australia


• Speed 80 km/hr

• CTBU units in

service

40,000 (74,000

total)



CTBU BT2-8609

Iron ore wagons, with 3 piece AAR

style bogies

170,000km/yr in ambient

temperatures of 0-50deg C in

Western Australia


• Speed 80 km/hr

• CTBU units in

service

1,500 (26,000

total)


Overloading

E-c

lass 2

5 to

nnes

F-c

lass 3

2.5

tonne

s

G-c

lass 3

5.5

ton

nes

G, S

ho

rt G-c

lass 4

0 to

nn

es

45 to

nnes?

K-c

lass 3

2.5

tonne

s

AAR limits

K-c

lass 3

6 to

nnes


Western Australia – SKF bearing damage modes investigation

Sample size > 5,000 pcs

Since 94% of the failures are

due to spalling, we can see

that it is predominantly load

related. Hence, this relates to

the issue of reliability.

Example - SKF bearing damage modes

investigation - 2010

0

500

1000

1500

2000

2500

Sp

allin

g -

OR

Sp

allin

g -

IR

Bri

ne

llin

g

Co

rro

sio

n

Fra

ctu

re

Oth

er

Damage Mode

Qu

an

tity


Result of overloading

Spalling (Fatigue) ~90%

cause of failure in some

Western Australia operators


Technical possibilities prolonging bearing service life

Higher capacity bearing without increasing axle dimensions

Lower friction and better functioning seals reducing friction

and minimizing bearing contamination

Optimised bearing design minimizing fretting (p-spacer) and

increasing safety (polymer cage)

Improved monitoring of bearing conditions allowing operating

conditions to be altered, or maintenance to be scheduled

Reliability approach in passenger versus freight

3


Reliability approach in passenger versus freight

Traditional model: the railway vehicle producer sells the

vehicle to the operator, who takes care of service.

This concept is used by most freight operators

New model: the railway vehicle producer sells the vehicle

including service to the operator

The railway vehicle producer focuses more on component

reliability

This concept is increasingly used in passenger operation

RAMS was developed to meet these requirements


RAMS (EN 50126)

RAMS = Reliability, Availability, Maintainability, Safety

Within RAMS there are for each component values called

„Lambda*T“ calculated and compared with RAMS standards:

The complete system (coach, train) has to fulfil the value of 10-9,

because it is a safety relevant item. This value must be reached

with or without barriers. Very effective barrier is for example

Condition Monitoring.

Severity of the event Consequences of the event „Lambda*T“

Catastrophic Death 10-9

Hazard/Critical Injuries 10-7

Major Stress to driver/workload 10-5

Minor N.C. 10-3


Example of RAMS fault tree for axlebox bearing in passenger application


Reliability approach in freight

Calculation example:

Load leading to calculated L10 life of 1.6Mkm. (L10 = 1.6Mkm)

Maintenance interval is 0.8Mkm.

Probability a single bearing will survive until the maintenance interval is 0.96

(using formula ).

Probability a wagon pair (16 bearings) will survive until the maintenance interval 0.96^16= 0.52

.

Implication:

48% of paired wagons will need to be brought in ahead of time. Unplanned maintenance impacting availability of wagons. Considering >10,000 wagons in service considerable maintenance and labour costs.

Alternative with higher capacity bearing:

Higher capacity, same load leading to calculated L10 = 3.2Mkm.

R (0.8Mkm) = 0.99, and two-wagon reliability over the maintenance interval is now 0.99^16= 0.85.

15% unplanned maintenance instead of 48%


Calculation example: freight car, lower capacity bearing

Single bearing:

reliability is 96% @ 0,8 Mkm

Pair wagons:

reliability = (96%)16

= 52% @ 0,8 Mkm


Calculation example: freight car, higher capacity bearing

Single bearing:

reliability is 99% @ 0,8 Mkm

Pair wagons:

reliability = (99%)16

= 85% @ 0,8 Mkm


1. Basic rating life – still the standard in railway industry

2. More advanced - SKF life modification factor aSKF

3. Very advanced calculation - SKF Bearing Beacon

Bearing life calculation approach

lubrication, contamination,

clearance, bearing internal geometry,

temperature, flexibility of components, …

Technical advancements extending wheel bearing service life

4


Typical bearing designs for freight

SRB (open bearing) CRB (open bearing) TBU CTBU

•Robust design

•Common outer ring

•Polymer cage

•Integrated contact seals

•Factory greased and sealed

•Polymer spacer

•Ready to mount unit

•Cold mounted

•Phosphated

•Robust design

•Common outer ring

•Polymer cage

•Integrated contact seals

•Factory greased and sealed

•Ready to mount unit

•Cold mounted

•Phosphated

•Robust design

•Polymer cage

•Robust design


Compact TBU (CTBU) advantages

Compact design->Shorter

axle length, reducing axle

bending

Polyamide cage improves

performance & safety

Polymer spacer to avoid

fretting corrosion

Excellent contamination

protection by contact seal

High reliability and long service life under high axle loads

In operation in Australia since 2000 (Class K, Class G variants)


Fretting in wheel set bearings

Due to axle bending, relative micro movements occur between bearing

components and between bearing and adjacent parts

Most affected interfaces are:

Inner rings – spacer

Inner ring inboard side – backing ring


The polymer spacer design

No contamination from fretting corrosion particles

Longer grease life and extended maintenance intervals

No inner ring rejection at reconditioning due to “side face wear”

No increase in bearing internal clearance -> longer life

Polymer spacer

Backing ring

Inner ring

Without polymer

spacer

With polymer

spacer


Long lip seal design for lower friction

Contact pressure = 1.4 bar

von Mises Stress

Mi (104N/m

2)

Contact pressure = 0.34 bar

von Mises Stress

Mi (104N/m

2)

Seal friction = µ x contact pressure

New design Present design


Bearing Energy Savings ratio 13%

Energy Saving 1 bearing [MJ]

27.556

24.000 3.556

0 5.000 10.000 15.000 20.000 25.000 30.000

Energy spent

(standard) [MJ]

Energy spent

(E2) [MJ]

Application example: Energy savings - standard seal versus low friction seal


Application example: Energy savings - standard seal versus low friction seal

Based on 200,000 freight

cars in operation at an

average speed of 80 km/h

the total Power Saving is

160 MW.

This leads to energy

savings of 1.6 TWh for

the fleet over the life of

the seals.

The total energy saving

for the complete train is

approximately 1%.

Energy Saving 1 train [kWh/km]

10,00

9,92 0,08

0 2 4 6 8 10

Energy spent

(standard)

[kWh/km]

Energy spent (E2)

[kWh/km]


Technical advancements in cage materials

02/08/2013 ©SKF

SKF Railway Business Unit

Resilient polymer material

Channelled roller pocket

design

Lower friction coefficient,

less roller slip and wear,

lower temperature

Self-lubricating material,

improved safety

Slide 13


"Oil - off" : temperature development in dry running

P- cage

Distance

220

°C

Steel cage

200

0 70 500 km

Temperature

°C

Polymer cage "oil-off" test


Through hardened rollers - proposal for heavy haul

SKF has good experience with through hardened rollers

Cleaner steel and lower risk of crack propagation

Case carburisation calls for a low carbon content before

carburisation (0.2%)

This gives a higher oxygen content than through hardened

rollers that uses a steel with higher carbon content (1%)

Oxygen drives oxides and slag formation which gives

inclusions and drives crack propagation

Higher hardness and wear resistance

Through hardened rollers gives 3-5% carbides

Case carburisation does not produce carbides

Carbides contribute to hardness and wear resistance


Next generation of CTBU – 45t for heavy haul freight

Design goal – 45t/axle

Higher dynamic load rating in order to get 2x longer fatigue life

that of TBU Class G for the same load

Same journal diameter and length

Same design features as existing CTBUs already proven in

West Australia. (P-spacer, low friction seals, polyamide cage,

long life grease)

Greater outer ring OD


Next generation of CTBU 45t – testing

SKF RTC test just finished, 200 Tkm.

Good temperature development through the test.


Next generation of CTBU 45t – testing


Adaptor design – outer ring creep

The adaptor design must allow the bearing outer ring to creep,

thus avoiding a fixed point load

There are adaptor designs that do not enable the outer ring to

creep. Either due to more than 180° contact or due to other

design features

Adaptors must be modified to accommodate

the larger 45t bearing

Principles of Condition Monitoring in Heavy Haul Rail

5


Increasing wheel bearing reliability

Two basic approaches:

1. Technical advancements

prolonging the service life of the

wheel bearing

2. More accurate prediction of

failures using modern condition

monitoring technology


Condition Monitoring in rail

Different systems and technologies are available to detect bearing or

other mechanical (electrical) component failure before it develops into

heavy damage or accidents.

Two basic approaches:

Along the track (bearing surface temperature detection via infrared beams

or Acoustic Waves Emission based devices)

Integration of sensors in the bearing or in the bogie

SKF approach is the integration of sensors in the bearing

The immediate contact with the bearing enables reliable extraction of high

quality bearing condition info, allowing early detection of bearing

degradation

Newly developed wireless communication further enables this approach in

heavy haul


Along the track hot box detection - infrared

Trenitalia DB SBB SNCB

Absolute alarm

Relative alarm – Delta T

Relative alarm – threshold for the hottest bearing

Single alarm (T linear dependent, value at

20°C ambient T)


Along the track hot box detection - acoustic

Railway trackside acoustic detector (photo Saferail)


Under track bogie testing

Wheel bearing condition

monitoring system integrated

into bogie testing machines to

evaluate the total bogie

condition.

The system allows workshop to

investigate rotating bogie

components without

dismounting for:

Certifying maintenance works

Enabling condition based

maintenance

Technical advancements in the application of condition monitoring in heavy haul rail


Coming from a research & development program

R&D focused on combining SKF’s bearing life and condition monitoring

knowledge

Factor aSKF

for radial roller bearings

hc Pu/P

0.005 0.02 0.05 0.2 0.5 2 50.01 0.1 1

aSKF

0.05

0.2

0.5

2

5

20

50

0.1

1

10

k =

4

2

10.

80.

60.

5

0.4

0.3

0.2

0.15

0.1

0.005 0.02 0.05 0.2 0.5 20.01 0.1 1c

Explorer


SKF InsightTM – embedding self powered CoMo sensors within railway bearing units

Power harvesting from application environment

Embedded sensors for measurement of

Load

Lubrication

Speed

Vibration

Temperature

Intelligent wireless communication packaged inside the bearing

SKF InsightTM embedded sensors allows operators to alter operating conditions to avoid bearing damage

SKF InsightTM is currently tested in heavy haul rail


Application of embedded wireless CoMo sensors

Wireless

communication from

bearing to gateway

Information relating to actual

operating condition is sent to

Cloud servers for remote

diagnostics

Smart Components are integrated into the bearing or housing.

Monitor lubrication, speed, temperature and vibration

Self powered

Understand how the bearing’s

service life is being consumed

and the risks of failure


Advantages of this breakthrough innovation

Eliminate damaging operating

conditions

Avoid expensive and disruptive failures

Optimise major overhaul schedules

based on equipment health

Improve process control

Reduced maintenance costs

Extended bearing life through

optimised operation

Reduce cost of ownership

Summary

6


Technical advancements increasing Heavy haul wheel bearing reliability

New technologies increasing wheel bearing service life

- Higher capacity bearings without increasing axle dimensions

- Lower friction and better functioning seals reducing energy

consumption and minimizing bearing contamination

- Optimised bearing design minimizing fretting (p-spacer) and

increasing safety (polymer cage)

Embedding self-powered sensors for accurate online condition

data, allowing operating conditions to be altered, or

maintenance to be scheduled.

Thank you for your

attention

milan soukup, skg railway: making heavy haul heavier: exploring technical advancements towards...

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