fzg - testmethods for lubricant related influences on the gear load capacity
TRANSCRIPT
G. SteinbergerTU MünchenB.-R. Höhn
FZG-Test Procedures with the standard FZG back to back test rig
Lubricants Russia 2006, 2nd international conference
Testmethods for Lubricant Related Influences on the Gear Load Capacity
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G. SteinbergerTU MünchenB.-R. Höhn standard FZG back-to-back test rig
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G. SteinbergerTU MünchenB.-R. Höhn
micropitting pitting
scuffing wear
lubricant related gear failure modes2/144.21.36
G. SteinbergerTU MünchenB.-R. Höhn load and speed distribution of test gears type A
test gears type A for scuffing test
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G. SteinbergerTU MünchenB.-R. Höhn load and speed distribution of test gears type C
test gears type C for wear, micro-pitting and pitting test
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G. SteinbergerTU MünchenB.-R. Höhn scuffing
scuffing: local welding of flanks due to breakaway of lubricating film
- no fatigue damage
- scoring/ scuffing already after short-time overload possible
consequences:
- increase of temperature, power loss and abrasion
- increase of additional dynamic forces up to tooth breakage
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G. SteinbergerTU MünchenB.-R. Höhn wear
wear: continuous removal of material from the surface with each mesh
desired:
- smoothing of flanks
- improvement of contact pattern (running-in)
undesired:
- change of tooth form
- removal of hardened layer
cosequences:
- increase of additional dynamic forces
- in advanced stages: tooth breakage
profile deviation removal of hardened layer
minimum thicknessat tooth tip
risk of tooth breakage
Rht
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G. SteinbergerTU MünchenB.-R. Höhn mircro-pitting
increase of dynamical additional forces + gear noiseinfluence on occurrence of pitting
5 µm
5 m
m
new
E
D
C
B
Adedendum flank
consequential damages: - change of involute profile due to profile deviations
load cycles
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G. SteinbergerTU MünchenB.-R. Höhn pitting
fatigue damage, caused by rolling contact stress
increasing of the internal dynamicsprogressive damaging until tooth breakage
result:
shell-shaped spallings on the gear flank surface
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G. SteinbergerTU MünchenB.-R. Höhn FZG scuffing test
Standard FZG scuffing test A/8.3/90 according to ISO 14635
Test parametersGear type APitch line velocity vt = 8.3 m/sDip lubrication with starting oil temperature of 90 °C in each load stage –No coolingDriving pinionLoad stepwise increased until scuffing occurs
Failure criterionVisual method: more than one pinion face width scuffedGravimetric method: wear more than 10 mg above average wear rate
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G. SteinbergerTU MünchenB.-R. Höhn FZG scuffing test procedure
0
400
800
1200
1600
2000
Time
weight loss measurement
Her
tzia
n st
ress
pc
[N/m
m ]
visual inspection
Load stage 1 2 3 4 5 6 7 8 9 10 11 12
Pini
on to
rque
T 1 [N
m]
0
10
50
100
150200
300
400450
550
15min.
2
gear type Av =8,3m/s
=90°Cϑtoil start
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G. SteinbergerTU MünchenB.-R. Höhn FZG scuffing test evaluation
Σ
Δ
0
20
40
60
80
100
mg
5 6 7 8 9 10 11 121-4
load stage
30 60 90 120 150 kWhtransmitted work A
wei
ght c
hang
e m
average wear
beginninghigh wear rate
failure load stage
low wear rate
high wear rate (scuffing) Scuffing line
Scuffing lines
Scuffing
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G. SteinbergerTU MünchenB.-R. Höhn FZG scuffing test results
Test resultsFailure load stage of tested oilCalculation of scuffing temperature according to DIN 3990
Typical scuffing performance
typical scuffing load stage
> 12––150 – 220axle oil> 12––100 – 220transmission oil> 128 – 125 – 7100 – 320industrial gear oil
9 – 116 – 83 – 532 – 68turbine oil9 – 115 – 8 2 – 432 – 46ATFEP oilmild EPnon EP
typicalISO VG
lubricant type
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G. SteinbergerTU MünchenB.-R. Höhn
modifications of the standard FZG scuffing test A/8,3/90 13/144.21.36
G. SteinbergerTU MünchenB.-R. Höhn comparison of different scuffing test methods
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G. SteinbergerTU MünchenB.-R. Höhn results of industrial and transmission gear oils
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100
200
300
400
500
600
700
800
2
14
13
121110
98764
C1 C2 C3 G1A G3 G4
GL3 GL4 GL4+
A/8.3/90 A10/16.6R/90 S-A10/16.6R/90
G6 G7
GL5
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G. SteinbergerTU MünchenB.-R. Höhn
scuffing integral temperaturefor different test methods
0
100
200
300
400
500
600
700
800
900
1000
3 4 5 6 7 8 9 10 11 12 13 14load stage
scuf
fing
tem
pera
ture
ϑin
t S in
°C
S-A10/16,6R/90
A10/16,6R/90
A/8,3/90
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G. SteinbergerTU MünchenB.-R. Höhn FZG wear test
Standard DGMK slow speed wear test C/0.05/90:120/12
Test parametersGear type CDip lubricationDriving pinion
weight loss of pinion and wheeltest result1 x 40 h2 x 20 h2 x 20 hrunning time
378.2 Nm378.2 Nm378.2 Nmpinion torque(load stage 12)
90 °C120 °C90 °Coil temperature100 rpm8.7 rpm8.7 rpmwheel speed150 rpm13 rpm13 rpmpinion speed0.57 m/s0.05 m/s0.05 m/spitch line velocity
C/0.57/90/12C/0.05/120/12C/0.05/90/12test conditions
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G. SteinbergerTU MünchenB.-R. Höhn modified FZG test rig for wear test
Test gear
Torque measuring coupling
Test wheel
Test pinion
Variable-speed motor
Speed reducer
Slave gear
Temperature sensor Load coupling Load lever with weights
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G. SteinbergerTU MünchenB.-R. Höhn FZG wear test procedure
0
0,1
0,2
0,3
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0,6
0 20 40 60 80 100 120Time [h]
0
20
40
60
80
100
120
140
160
Pin
ion
spee
d n 1 [r
pm]
weight loss measurement
profile deviation measurement
90°C 90°C120°C
0,05m/s (13rpm)
0,57m/s (150rpm)
Pitc
h lin
e ve
loci
ty v
[m
/s]
t
gear type Cp =1853N/mmT =378.2Nm
C2
Pinion
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G. SteinbergerTU MünchenB.-R. Höhn FZG wear test evaluation
High wear
Medium wear
Low wear
wea
r sum
running time0
100
200
mg
20 40 60 80 h
300
400
500
700= 90 °Cϑoil = 120 °Cϑoil
low wear
120100
= 90 °Cϑoil
medium wear
high wear
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G. SteinbergerTU MünchenB.-R. Höhn FZG wear test results
Test resultsWear category of tested oilSpecific wear rate of tested oilIntroduction of specific wear rate into wear calculationaccording to Plewe
Wear category
> 500 mgvery high< 500 mghigh< 200 mgmedium< 50 mglow
Sum wear per each test periodWear category
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G. SteinbergerTU MünchenB.-R. Höhn FZG micropitting test methods
1 week (2 runs),screening test method
6...8 weekstotal test time
GF-class (GFKT)failure load stage,GF-class (GFT), information on longtime behaviour
test results
KS 7, KS 9KS 5...10 + endurance test
test course
1.5 l in the test gearbox
total amount 25 l, about 2 l/min
amount of lubricant
dip lubricationspray lubricationlubrication
type FZG-C-GF, Ra = 0.5 ± 0.1 µmtest gears
FZG test gear rig, a = 91.5 mmtest rig
short test GFKT(DGMK 575)
standard test GT(FVA 54/I-IV)
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G. SteinbergerTU MünchenB.-R. Höhn FZG micropitting test procedure
running time
load
sta
ge
stage test endurance test
runn
ing-
in, 1
h
3
5
8
6
10
7
10
89
10 10 10 10
running time per load stage16 h
running time per load stage16 h
running time per sequence80 h
running time per sequence80 h
failure criterion: ffm > 7.5 µm
failure criterion: ffm > 20 µm or pitting
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G. SteinbergerTU MünchenB.-R. Höhn FZG micropitting test evaluation and results
failure limit,load stage
test
0
2
4
6
8
10
12
14
16
[µm]20
load stage testrunning time 16 h / load stage check every 80 h
endurance test
5795 945 1094 1245 1395 1547 1245 1547
6 7 8 9 10 8 10 10 10 10 10 load stagepC [N/mm2]
lubricants:ISO VG 32
FZGmicropitting test
C / 8,3 / 90
micropitting load capacity:
mea
npr
ofile
devi
atio
nf fm
test terminatedbecause of pitting GFT - medium
GFT - high
GFT - low
failure limit,endurance
test
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G. SteinbergerTU MünchenB.-R. Höhn FZG-micropitting short test
aim:
• valid for lubricants with different viscosity
optimisedconcerning:
• duration• costs
• lower amount of lubricant
• good correlation to FZG-micropitting test
short test method, screening testto evaluate the GFT of lubricants
FZG-micropitting
short test
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G. SteinbergerTU MünchenB.-R. Höhn FZG-micropitting short test procedure
running time
load
sta
ge9
3 ru
nnin
g-in
, 1h
7
running time per load stage16 h
running time per load stage16 h
failure criterion: ffm > 7.5 µm
max. running time: 33 hmax. running time: 33 h
max. duration: 3 dayswith repetition: 1 week
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G. SteinbergerTU MünchenB.-R. Höhn FZG-micropitting short test evaluation and results
DGMK-FZG Micro-Pitting Short Test
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2
4
6
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16
18
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5 5 6 6 7 7 8 8 9 9 10 10 11 11 12Load stage
ffm
av.
max
. pro
file
devi
atio
n [µ
m]
GFKT-lowGFKT-mediumGFKT-high
Running time 16 h / load stage
Steinberger01.06.2002
7
Test conditions:
GFKT - C / 8.3 / 90
Roughness of thooth flanks in all tests:Ra = approx. 0.50 µm
Candidate lubricants:
Ra = (Ra1+Ra2)/2
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G. SteinbergerTU MünchenB.-R. Höhn FZG-micropitting short test examples
lubricant GFKT-medium
lubricant GFKT-high
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G. SteinbergerTU MünchenB.-R. Höhn pitting test methods
• PT C/9/90
• PT C/10/90
• PTX C/10/90
• PTX C/SNC/90
• PT C/LLS/90
• PT C/HLS/90
• PITS C i80 TS
• PITS C i95 TS
standard pitting test (single stage test)
practice relevant pitting test (single stage orapplication test)
pitting test with load collective
pitting test with oil ageing
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G. SteinbergerTU MünchenB.-R. Höhn comparison of FZG pitting test methods
standard pitting test PT (FVA-information sheet no. 2/IV)
practice relevant pitting test PTX(FVA-information sheet no. 371)
FZG back-to-back test rig, dip lubrication with constant oiltemperature (90 °C), pitch line velocity 8,3 m/s
single stage testload stage MS9 (T1 = 302 Nm) orMS10 (T1 = 372 Nm), depending on viscosity
single stage testload stage MS10 (T1 = 372 Nm), independent from viscosity
extension to application test possibleload stage MS9 (T1 = 302 Nm) orMS11 (T1 = 450 Nm), dependingon result of single stage test
gear type C-PTXpractice relevant flank modificationssuperfinished - Ra = 0.1 ± 0.05 µm
gear type C-PTno flank modificationsgrinded - Ra = 0.3 ± 0.1 µmmicropitting less or no micropitting
failure criterion: 4 % pitting on one pinion flank or 15 µm profile deviationresult: load cycles for 50 % failure probability LC50
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G. SteinbergerTU MünchenB.-R. Höhn FZG pitting test result
NPi
Failu
rePr
obab
ility
in %
80
60
40
20
10
2 442 6 8106 107
LC50
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G. SteinbergerTU MünchenB.-R. Höhn FZG pitting test results
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G. SteinbergerTU MünchenB.-R. Höhn modified SN-curve concerning pitting test result
106 107 108 109
load cycles at pinion
1100
1800
2000
2200
2500
1200
1300
1400
1500
16001700
105
hertz
ian
stre
ss p
C [N
/mm
2 ]
SN curve (straight lubricant)acc. to DIN 3990
ZLp50T = σHP50T,50%
σHPdauer,50%
„new“ SN curve fortested lubricant
MS 9
5•107
σHP50T,50%
σHPdauer,50%
N
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G. SteinbergerTU MünchenB.-R. Höhn Summary
FZG micropitting test
FZG pitting test
FZG scuffing test
FZG wear test
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