690055
Ne
Cr Un
Euro Europe pean an Rese Resear arch ch an re
Engi Engine neer erin ing, g,
epri eprint nted ed arch arch 1971 1971 from from 1969 1969 SA _Tra _Trans nsac acti tion ons,V s,Vol ol 78 by
690055
o r S e l L oo o o se se n n g
New Cr of Fa
ne
U n d e V ib ib r
on
er ar urop uropea ea
IQUE IQUETE
etho etho
an appa appara ratu tu no
to repr reprod oduc uc cond condit itio ions ns of vibr vibrat atio io to loos loosen en bolt bolted ed join joints ts bu cond condit itio ions ns
It ca
rs lo
that that ar no only only cert certai ai
hich hich also also clos closel el
si ulat ulat
be show show that that prop proper erly ly prel preloa oade de
resu result lt
rota rotati ti
occu occurs rs betw betwee ee th
atin atin
In addit addition ion to fati fatigu gu
on
thre thread ad an
.sur .surfa face ce of th fast fasten ener er an
th
clam clampe pe
offe offere re
fast fasten en ti
lo
th bear bearin in
for.t for.the he
lu in
lite litera ratu ture re
to mach machin in
that that ther ther have have been been th
an vehi vehicl cl
th
tain tain
in
tt
pt to
lain lain th se
rt nate nately ly to
to th icie icient nt
practi practica ca
th th tt
re
tate tate no
ar la
nd la
lo
form formul ulat ated ed an
in
or
pa re
r,
lf-l lf-l
in
),
ever everth thel eles ess, s,
(t
is th
extr extr
ia im
In
ti
ti
ta ro join joints ts
th
te ts
ai ly
here here
ig ll
el -l th
ne
in ch
reco record rdin in
paper.
tr in
pl tely tely
el as so
so-c so-cal alle le
affi affirm rmed ed that that tran transv sver erse se vibr vibrat atio io te ti
le
self self-l -l
il
de ri
ic
th
lo
te
ra
enin enin
in
le to
po
to
rf rm
is
io here here
this this ri
eval evalua uati tion on
is
gengen-
phen phenom omen en of self self-l -loo oose seni ning ng
ta
ts
is an
in
answ answer er to th
ua tita titati tive ve
pera perati ti
of
rrie rrie
if ic lt
os seve severe re cond condit itio ions ns fo self self-l -loo oose seni ning ng
give give prac practi tica ca
In
is
faste fastener ners. s.
ew test tests, s, whic whic
on
from from anot anothe he
th
Optim Optimal al Lock Locking ing of Bolte Bolte Conn Connec ectio tions" ns"
te
selfself-loc lockin kin
tr ly
Refe Refere renc nces es at en
affi affirm rmed ed
exac exac proo proof. f.
rota rotati ting ng loos loos nonl nonloc ocki king ng fast fasten ener er as ee
el as auer auer Le
*Num *Numbe bersin rsin pare parent nthe hese se desi design gnat at
ti
th thre thre
auth author or appr approa oach ched ed th prob proble le
ti
er ly lo
an Lynn(2) Lynn(2) have have test tested ed only only axia axia dyna dyna ical ically ly load loaded ed bolted bolted connec connections tions
nn
la
tota tota
in
SelfSelf-Lo Loos osen ening ing an
ro
-r acti acti
of la
erat erates es th
ween weeney ey (1), (1), as
lt
tw th
ro
In 1966 1966 th tr
answe answers. rs.
oodi oodier er an
does does
loading.
impr impres essi sion on
ti e, th re
xplo xplora rati tion on to de
rf
ould ould
tota tota Io it
with withou ou find findin in
ited ited
ti
prio prio theo theory ry an also also pres presen ente te
(4-6 (4-6), ), in
ta
it
corr correc ec solu soluti tion on to ta
is
th rela relati tive ve
asse assemb mbli lies es
ho ever ever give give th
an appr approa oach ches es trie trie
ti
In 1966 1966 Pala Paland nd (3 prec precis isel el
th
sign signed ed to prev preven en self self-l -loo oose seni ning ng of thre thread aded ed fast fasten ener ers, s, os of th exis existi ting ng lite litera ratu ture re
fo part partia ia loos loosen enin ing, g, whic whic
parts.
operation operation and effeCtiv effeCtiveries eriess6f s6fself self"loc "locking kingelem elements entsdederesu result ltan an seve severe re da ag
an expl explan anat atio io lt
os
of dyna dyna ical ically ly load loaded ed bolt bolted ed join joints ts
th re
ngin nginee eeri ring ng
self self-l -loo oose seni ning ng of thre thread aded ed fast fasten ener ers, s, they they have have
nd th
ater ateria ial. l.
an
the mech mechani anism sm of selfself-loo loose sennin
rela relati tive ve
betw betwee ee
co plet plet
actu actual al
fail failur ure, e, self self-l -loo oose seni ning ng is th
freq freque uent nt caus caus offa offail ilur ur is
ak it poss possib ible le
Rese Rese rc
n ke ke r
in
it
os ibil ibilit itie ie
il be show show an disc discus usse sed, d, with with
ABSTRACT----------------------------------------------------~-----------------he theo theory ry of self self-l -loo oose seni ning ng of prel preloa oade de tion tion
he subj subjec ecte te
an
ig
lf-I lf-Ioo oo test test
ui
etho ethods ds ar
to vibr vibrat atio io in to
desc descri ribe be
bolt bolted ed conn connec ec
is disc discus usse sed. d.
us
ilur ilur in
is
ne ly desi design gned ed test testin in
he sign signif ifii-
ta
pl in
id
lf-l lf-l
an
disc discus usse se in conn connec ecti tion on
ev lu ting ting lo
be appl applie ie
is iv
li ie it
posed. 314
in
ro
rtie rties. s.
th
in
to
th
achi achine ne that that yiel yields ds quan quanti tita tati tive ve
ro
le te ti
ll in
tion tion is pr
th ai
of proposin scientific im ifie
in
nd sophisti ated test
io
ethods yg
st•
It is
per-
form
se f-lo
in
se
thread is th sl
s.
se
seri
self-locking perfor
nc
te
se
lu in contact.
fina answer on th
ir ly
in
ss re
th
li
dditiona friction forces origin te from the'
of variou 3).
tistic
is
te
su ta le
lyin
Similar
st
fi
sl
se f-lo
in
been reached rise betw en th HE
CH NISM
th ll-k
is
la
lf-l ic
tw soli
external forc
in on directio
orki
th
ss ll
odie
le
an ad itiona
th
forceQ is
iv
ll
tan(-cp
le
he bolt coul
th friction
ta
P)
tan( -c
P)
(tan -c
1.15 fl)
fl
DH fl
lo se by itself (without th
ff-t
ly
To
applicatio
re
it
(1)
th sl
th so id
lo io
f-
ti
r,
th
in
th horizontal pl ne re resent th
th
'"
tw
ri
"F
forc
show weights, whichcanberegardedasasim
pr sent th thread an
contac surf ce of
foll
ove-
ri io
is smalle th
angle. Fig.
rts.
rc
is
ll illu tr
thread fl nk an th
la
fe ts
ti ly sm le th
in
in
se in
friction forc betwee
rc
la
F- OOSE IN
to th
fe
th
re tl
fr
st tr
ro
L·tan
ly Fig.
QJ
(~IP)=
im if
-L·tanlp lt
in
ibra io
OJ
tan
(-Ip
tan
conditions
te 315
in
st ic
ti
316
G ER HA R ro
ti
lu
id
ll
lu ri
te
re
th
ri
diameter (equivalen
ro
th
th
is,
if th
m.), he specifie values feirthe relative
3/
ro
SjF
io faces, ha been very
idel
owever if relative /o
th
in
rt
ic
is it
il
ta
ti
rf
th
la
tern
rc
th
ra ial. th
ri ti
th
in
ir
ll
ts
th
of heav
oc ur betwee
ta
re
(Fig 4)
eneralized
otio
(4)
preloa ry
rf
ts in th
ti
to
to,
U NK ER .
10 proximatel
la
tr
thread friction angl will
co ditions, th down to
rf
H.
ra ia
is la
ld'ex lain
la
(3). in
it
lo
in
in
impact loadin
threaded letely lo ir
ti
lt ir
(1
:th
ti
re ti
ie
re
ti
luti
ro im tely
/4 in
This
t-
lt
everthel ss
to
ti
te
this loosenin
ha
il
alread
te ti
in
caused
preloa
ro r,
.th circumferentia
friction forc
resistin
th existing internal
off-torque is.
(6 lo
ti
in
in
(3)
re te
late
rotati
lo
in
relo
le
iu
/1
te ti
th
SIP/a
lo
-<
ti
ts
t-
maximum
le
in
ir lo
le
rt
lt
rkin lo
rd
,0
lt
in
in
it
in
rv
le equal
ti tw
is
th
thre
la
la
la or axiall
lr
lo de
rt joints
th
connection create rf
lati
th
in
inte
ri
th
ta
ti
rf
S:8
th this re
r? oodier an
ls ti
te
radial slidin re
ti
la
otions betwee this re th
ti
lt th
tr
tw
ti
ll
ri
th
ta
ti
th thre
la
th
relative
ta
rf to th
tr
ti
rs
lo
in
icti
rt rith
420/0.
thread
ri rule
relo
or dyna ically transverse loaded joints th
eene have
io
th
ic
th
lF,t
to
ri ti
ri ti
rc
rc in
tr
itte
tw
li
re
axi-
th th
la la
in
tr in la
rt
thus betwee
rc th
th
lt to
lu
thread flanks
litu
tr
rs
li
in
li
th
lt
tr
rs
is
rt
th
thre
th
the internal off-torque forc
re ti
tr th
joints Toff i~Y'T'
tan (-¥):-
is usuall
rs
lt
join
tr
re
re
in
ra
xperie ce show that thes
os frequently fail by self-loosening le
lf-l
in
is th
te in
th
y'
driv shaf transmit ig
li
ac epted.
beco es sufficient
rs
ibrati
th
omen
to th
crow
heel
ro
317
S E L F- LO O S E N" IN " G O F F A S TE N FR S th
iffere ti
be
th thes
ea
it ofte
ro
nd
tw te h.
ur
ch re
sv rs
slippa
ro nd
re
by themselves.
ua ly in contact, becaus
adjacent bolt connection is
th
th tr
re
av ly
ad
th
th r. It onslst ested.
deformatio
la
ic
la
turn
tr
by he fast
sv rs ly lo
yn
transverse slippage takes
on th crow wheel.
in the
de ring th rotation
th
the
ro
~e
on bolt
te
th relati
emen
plates (cause by th
tw
th
tw
pe
transverse loading) wa recorded by
the he tightened. both bolt torque
high spee recorder
the join is axiall ca
cu be ti
or coaxiall
se su
th
loaded transverse slippage
oa in
la
us
rt (for
pl
lastic
for-
.be ri
co
ul be ight ne r)
prop rl ti in th
in
nism
determined
tr
sv rs ll
Schoellham er
lo
joints
of th
aboratorie of Daimler-
Benz AG., Stuttgart. ha determined th of severa fasteners. includin nami
transverse loading.
transv rs
pa
ff torque oose
re se
thou th
hese test
self-locking type unde dy es
st th fr
to th
of
ibra io
in
nc
ha th
ter-
fina ly rotate
tern
off-torq
ac in
ua ed im
in
te ro
relo d. join
ibrate
ss th bolt
loos
external off-torque wa
induce
transverse force. th
it
wa no determined.' frequenc
ther increase of induce
external off-torque de
vibratio
values indicating clearl lope
Fo
by he
roof fo th inte na
th relative
re
Whena certai
it increas-
Toff
th th fast
rs indu
torque
dur-
th
easured.
corded
This
that ther
dg
fe
ua impuls
is
an internal off-torque
th
li inatio
ff-torqu
resulted in negative torque iall
of self-l
easure
lo de
king
of -Q.58m gf (50.
thre iv
en
inv-lb) wa re
internal off-torque wasapproxt
ff re ti lrte
he
external off-torque
th fast
ssit
se ir
In
nc as
br io
necessar
si
to he
(5)
(-cp)
relo
it increasing
as reached, th external off-torque fo loosenin center of
torsiona vibration.
TO PREVENTSELFLOOSENING
r----
rt
-
re
it
lock
washer
BYMEANS OF DESIGN
--
it
1 ) 1 )
rdin su
re ious esea
at tota se f-lo se in
rk it as to do
sjoints ha
~.
~.
thread islargely diminished by th
\~
of an alternatin
workin
load
rtia lo se in
."""
th
intern
he loss
off-torq he
relo
ca se he tota
co pression amplitud
ot ti
le
to
is roportiona to th in re se nt
he
lt rnatin
furthe loss prel ad ti
hi failur
orking load (a ial)
is
ig
oose in torq
fo
relo
fast
rs
tr ns
th
tota
ro ti
in transversely loaded connection
lo sening ca
oc
as soon as th clamping
G ER HA R in tran vers
slippage
twee
th
la
part is
it is
used
ot
nd to
ip ri io
ly by tr
curs
rans
ai tain su icie
deal with th is
te
sv rs load or tran vers
th
lo d.
U NK E
this paper
in
"self-loosening" branchof th failur
esig rule or
of pr lo
om
la pi
H.
partia
oi in
self-rot ti
ech-
lf-loo enin is
ll
lo .De ig in th
la joints th
re lo de
centricall
The proposed concep of th self-rot ti
of
eari
th
icture
by introducin
th
"self-rotating
ti ue ailure ic
betwee
ca s)
lete
se re
ch
unde
re ains
ol
an
ni
th
atte pt is
ad to illu trat
dy amic ll !; lo de
ig
th failur
bolted conn ctio
(7).
hhi
il re
(i re
illustration showstha th atig
br
eddi
of preloa
en
values afte tightening
na (S tz n) du to pl ti th
la pe
rt
de
is ta
basic.rul
(transvers load/frictio
T/Jl
ci nt
to
ke
od rn rule ar
therefor
re th
or
on th
de re
pr lo
tr nsvers
lc lation of olte
base
ti at
of th
th
necessar
of
bt in
ddin by ti
lipp ge an oc ur conn ctio
(8
residual clamping force, (S tz n)
te in
coeffi
nd th
catter
as re re nt
in th
following equation:
f-l ithe
scatte
were prob
th it
he th
fastener co ponents.
sufficient residual clamping forc
rm ti ns of th fa te er
bvio sl
ably caused by partial self-rotating. ig
thread flanks of th
is
ld
deformations or even by insufficient tightening In
th
to
This requires that
echanism of self-loosening
st ners
failures unde vibratio ro es ."
ri
ll
fo avoiding bolt failure,
kage or by self-l osenin
is to
pply
6F
max
(6)
where:
(7)
th
if re
rs re
sitwas previously shown,usingth exampl only if th
join fastener
ar
uneconornicall
th lt
onne ti ns
re th
relati
re
ende
eyon
ovements
te
to resi
of fastener th
crow
overdt en
ic ll ex ct anno
lc lation
lway
In thes
co
ofth
th re
cl de
by
cases, us is re-
with self-locking elements that
intern
ff-torqu
hi
occurs
he
inherent self-locking is lost PROPOSEDNEWTEST METHODS
AND
M A CH IN ER Y ince relati
ve
nt
tw en cl
ed part
fastener cannot be avoided by only an ti
jo
self-locking fastener have to ro
effectivenes
of such self-locking fasteners. Severa test re in
cert in
pe ifie
condition ra
lu
ig
so att
type of lockin
ta
ta
lo
ondition
ta (s
npreload
in
re aste
ti rs
th
th
in
co diti
).
reload It is bvio
re ther sp ci ic ti
iv
al es
319
SELF-LOOSENlliGOF FASTENERS fo installation torque breakawa
torque an
prevailing
torque.
th
it
this pa er an entirely differ nt approa
is prop se
Since transversel loaded joints·tend moretoself-Ioosentng, th
test ro edur firs
sugg sted imitates th se actu
tt
re
ts la
th
th
an
displa emen
an
displacemen •.
th
pick
ll
ib
it
lu
th
-s
si
fi
external thread
it
ay be used te st
is se
sure
ts
it
ro
le
le
tric
th
.fl
tw
stri
to
specia li ea diff rentia
tightening an loos ning angles ter.
ic
flexible shaft. increase
sp
itte
to
te ti
tr ns erse forc
st
ee le bearings to void galling.
type offatigue test th
th
hell testin
is is
iv
ld io
se fo th
re
re
le ents
lt th
ld
bolts.
relo d.
displa ement.
It
is in
bushin
sw se rg
in fo testin
sh
The"force is tr
transverse lo d.
ti
lo
sh
th
differen fo th variou lo king
ro
s. this
isti sp
to re or
he prod ct transv rs forc ca tl
onditi ns
si
internal thre ds is lace
is mea-
transfor ers.
re
tt
asur th
ch ng able thread
he
it
linear
sp im us in
nd insert
in re sing fr qu nc 5/8
st
init
tartin ff
xi
nerg
fo
(a
lockin
as ne essary fo rotation loos ning
Th
elements. machin
is
which is signed fo thes tests.
an differen pulley
allo
testin
frequencie
of 1500 3000
4500 cpm. in chin
generate
resultin tiff
ss
stri tl
tr ns erse forc spri fu ctio
Fig.
transv rs
st
slidin
otio
et ee
is in ep nd nt of fr qu nc lo
ra sm ttin
th ec entric adjust
nt
sh
thre
diff re
nd rts)
rrange U-shaped shee
nt is used fo test
fo th
achine
la
th
s.
th co ne ting plat
th '....
is
transverse
fati ue strength of bolt
interest if th fast
teners with serrated bearin is
pure transv rs lo d-
Uvshaped
it
sp
it
etal specimen that transmit th
forc it this rran emen
C ON N EC T N G P LA T CE FO R AN S VE RS E ORCE
pplication
tw
surface.
in
shee
rf in
In th bottom pictur
32
G ER HA R
any combinatio
ing the xi
H.
U NK ER .
of transverse recordin
methods, th
testspecimens were restricted
in
.. in X-
ns
hookup
om
cpm), the
-Y FT
dl
of of elf- ocking
he
fa teners is in
multipkled
....._____
.: -c
';;:
.:
$P1;
....
O lS Pl AC E ME N T
ADJUSTASLE EXCEIITER
RECORDER
L OA D C E FO I'RHOAD
S HE n
M ET A
S PE CI ME N
B RI DG E
A HP L F. FOR
PRELOAD
B RI D E · A MP LI F FOR
F.
POTENTIOMETER RECORDING
COMPR. LOAD FO
vibratio
machin
TRANSVERSE
DISPLACEMENT
to
SE F- OO JmIN
321
OF FAST NE
type an th
echanica
lo
size MIO test result
om
it
lain
sh rs
urin
that thei
of scre
ti th
ha in
ness of 771\ (HBSO:::13 kgf/
).
ck
ll
rs
re
itio
al test th specimen
kgf
re
rs
fast
rd":
it
stre
pt thos
IS IWl
er run
Teste
Specimen
------~~~~--------
Dimensional Specification
Scre
';I! a3 ,c:~ ,: ;.s~
30
Thread ton Bolt 6g Nu 6H ominal
ax thread
ll
0. 0.01355 in
screws
tc
.5
196 Series, ominal ll
ax thread nc
0, 0.01142 in
oc
scre s,
1960 Series.
.586
Threadtole
lt
in ll
thread nc
0. 93 '0.00759 in
Spring
ashers IN 33 (AI) lu spring
ashe
IN 12
Free Spinning Lockin Screws
tols Bolt 6g
Thread screws, MI it
1.5
30. ominal
triangular teeth,
ro ve
ri
lat-
ax thread
ll
0. 44 0.01355 in t6
screws, M1 it
lo
1.5
30,
ra ia te th
and circumferential
curve
on
ll
nc
0.34 0.01355 in
ri formin
nwash rs
continuous
originally.preloaded lass 8.8(si il it
to
sp
pm,
PLOTOF TRANSvERsEFORCE AND DISPLACEMENT
io
Socket head ca
test
750/0
th ie
ll test
drive (1 cp
er
This
5500 lb
Grade 5).
X-Y
he free spinning
onlockin
ll
of higher hardness (R
properties in Table 2. Screws of th
.s
in
GE HA
322 ,(HYSTERESISCURVES)- Th placement
in
schemati
drawin
slipping bolted'connectlo
force/displace en
diagra
subjecte
twoplates
U NK E
in to
dy
tted line represents th
amic transverse forces
H.
hich ar clam ed
is larger
in
th
therefore th
threads
lo
in
soli li
er
li
is lace en
in th
absorbed friction energy is larger too. ia am re esents
join
.i ha
th
,T
in
ef re thread slip in slip in
an
th
sc ew thread is
rted
th
site
ca
pr ceed to
(f
narrow thread
tolerance) or to
is
is being transformed into
ly th scre
ea
li
re te
is
last
force/ is acemen
fricti
rg
th
en
tan
CP),
ef ecti
ia ra
te its
fo
arin surf
ic
e.
th
th
ea
ar ad
here slip in curs
distance
ec
ca
ro
as ener rotati
becaus
rt es
in
only ther
ca is th
ta
lace
scre
re
lyonth se ri ti
ecimen
HV
Proportional Limit.
UTS,
kgf/mm
kgf/mm
(Dia on
e H
yr 30 load
e H
Remarks
Al 11
117
156.400
166,400
156,400
166.400
360
270 .96,600
Mech, properttes
6f--
116,600 275
119,500
133.700 (0.00197 in.) from surface
85 120.900
139,400
Ai.
F- OOSENING
OF FAST NE
323
fo thread
it
ex-
0:: III III
cc rdin
to
ig 11.
III
5! 0:: 0:: LII LII
(F
-e
f1
LII
0IL
FT
co S PL I
AG
HR AD
O NL Y
.C
is OOjo
unde transverse vibratio Fv%
60 40 20 O,
.0
0,2
.0 500 400 300 200 100
rs
forc
FT er
is la
200 300
spinning lockin
scre SPECIMEN
500 [K f]
SPECiMEN
C2
G E H AR D H .
324
U NK E
starts to fully
with er
force/ isplacemen
hy eresis
urve
It
with the
lt 4 0 0 / 0 of the
represent the load/deflectio
curv
0.36
prel ad an during 10
machine. Fig. 13 shows the
unct on
angleofrotatton
isplacemen ll free pi ning
of
X-Y erie de ribe late Fig. 15 shows the first 50
10
)IJfo
10
cp
frequenc
200 cycles,
Fig. 14 adju tmen (z ro load amplit de
do
±0.8
0an
14.40/0 respectively
the angle
3000 3000
cpm,
intoconsidera-;
and is approximatel 20 in several tests independen of frequency.
30
It the fo ce
of th frequency. In luence th loosenin
Fig. nonl ckin
the
au ng he
oc-
cycles. the
ta in
crew AI freq ency 10 cpm
tops an
deg
fur-
he os of prel ad is due to surface.
relative
50.
by the
roce
FV
roce
0.6
FT
14
AI frequenc
3000
cpm
S EL F L OO SE N N G
OF
A S TE NE R
325
ex-
als show clearly te es
the hys-
ac eriz st re is
rv
li
co
(10)
thread slip-
ts th
recorder
11, which show
imitin
lu
the exceedin is
ri
il
ited fo
lu ti
ta in
used.especiatly th
-Y
ited
lo
st
io
lockin
te ti
re
ci
ar
sp ce en
ll ·Fig 16 sh
cill scope. ac in
to
an
actual
T-
VlBRA TION
rg lute
axim
re re
re
tp
of th
st
ctio
transverse forc te
ia am stif
fr
sVi rati
tr
th
ll
rb fo
th
absorb exactl in lu
that
ar
in th ex re
rictio
re
ce th pr
ct
ti
rtance
if
tota se aratio it
so ed
smal
re
transverse forc
rc ro
ti es
ll
se to in
is lace en
rg
en su jected to transverse displace ents ,.,rillbe called "vibrati
in
rm
is lace en
/4 cycle:
in
roduct
he pr
"d an
sico th
tw
th th
re
lt
fr
ay
rst.
Twere recorded on
transverse forc
er
ct
V. tain
fo "d
relo isic
er
lti-
(8)
electrically trem ,,'_'
in co
emen s,
and
/4.c cle,
of eq al im
ep fr
ib ti
se
d·F
_A
th al es ar
will
steresis curves
slips under alternatin te si
ra
to rotate
transverse forces in connection with relatively smal
as larg er si
elements
i. Slipping joint
since
ie at
ca se thepre loaded scre
ro
esti
'be
co er
ar
in ll
ll
transverse force.
is la em
ic
th
re
fric io ),
ul absorb
ltiplyin
is lace en circui
as
an
il fr
ulti lyin
th
si
al
th
tw am lifier
transverse force. co
"d
ercially
ltiplicati availabl
an FT electrically
co
onents
it was possible
(9) _.
·I
.,
asin
. . , I : ,: ,: ,' ' - ; ,, ' .' :~ :" .
th
¢: 0n case th
ener
fo
full cycl
ld
ti
te in
lo
re
an rotati
im ta
lo se in
an le
sl
as re istere
as
zero ..
QQ_
Fv%
Kgf
lOO
0,8 0.6
lO
SO 10 SO 40tf 300 200
100
100 200
vers
300
forc FT versus displace
1,00
le
SO
in
cz
ib atio
self-l ckin frequenc
-.
fo fr scre
10 cp
v. _-
_ _. . _ -
and
326
G ER HA R a)
tan ••
,"
91
rd
~=~
,8T·
H. lo
st
ti
(s
01
t)
angl
Kgf/
fi
(1
re
the
it
potentio eter an th
scre
subsequently
to 1000/0 preload. 17 sh
recordings obtained
loosening settings
fu er
ti
th
djustmen
frequency (pro
so
tota
as descri ed
bo e,
re
as follows: ccentric
ma 00
lb
th scre
recordin
tightene
U NK E
to roduce
3000 cpm,
in
).
fo
ig
sh
afte on tighte ing. test
'" 210
the screw retain b)
M2
T02 . . F l IE
02
lo
500/0
M1
th
2d "0
te
00
s.
rotation lo sening an th
re
angl
corr sponds to the
£t:t!.d0!2.2~ -w.•• unserrat
scre
of th
sa
di
nsions is
If
loses 120/0 pr load
partia
rotation loos ning
nd 3fP/o by
in.), whic
re th
(C)
se rate
02
0. 06
.)
ig
scre rese
sa
si th
s.
ff r-
th
ture sh
th lo
unde th sa
r----
corre
ti
in
conditions
ss xcep
is
te
it
l02
so ti
sm le
te
ti
rm
non is
ic
d)
M2
M1
m•
ma•1
CM~d
ff re
hard washers.
is se rotate
In this
ic
-~.d
sh
th
lo
lo se
in
nl
st
'fi. Fra2
"y
'FlO!
fasteners reported in fere
rg
le
ls
it
eccentri
positions) re ording preload.
an vibr tion product. th latter co pute
produc
ei
displa em nt an
st ngle of rotation th
el ctroni ally
transverse forc to descrlbe th
test procedure. actual hysteresis curves
th
erformance
f.
lockin
le
nt
isadvant ge
eing
SELF-LOOSEl:'lINGF FASTENER
327 va
SOF
WASlfliR
X-
CYCLES
-
'5
00
rs to
l;?'
pr 7D
ANG\-E
III
in th
ia
it
nd
le tr ni
ly or la
ui
t.
ltipli
ti
ratori
testin
ll
re
ires
-Y -Y
recorder
an
li
ot
tiom te
tronic re or in
ic
is ne
circ it
on elec
le
.
si il
if
tu
el
ib
ro
ed
io ts
<[
-_._-
....100
'"
it
'"
ma._ '1210m",
ic ll
'" '"
.
'"
4S ·~-- -~ ;':::_':':"::::~:.:!...-+-71" -----t
ltipli
ar tely an
:t
IlO~--..:t:'_-+--1~---t'---r--,1D
le valu
then
tr ns
rs
ulti li
or
ispl
uall
he
il
:::;
pr
ss
re point (suc
-'
II:
0..
re
ri ge am li iers
ic
interr ptio
to
an
ut itte
tr
reatin
ro
dure
thre
60
....
cy les. th re
40D+----t---+---r------:>:""""-;--+----t
re
III
.
lS
----t----!----:7'?r---;;H---+----t'O
,.
3001+----t-"7'~---1--7"-_ ---,-----t6
in
it th
ib
th re
ibrate
loos
toti
ll
in
pl tely ibration pr
th
rv
re
uc valu
es
ic
ea ro
'"'"
rv
It:
xi
'" 100
S OF T
III
'".,.,
2S
th
;;
'"
ubje
lockin
to transverse vibrations
te th
ry of th
Infl
ce-o
thre
it on
nl
ki
crew with national coarse thread 3/8
'"
el
ry
th
0;1
I"'"'
th
-N
In
'" ::>
th te
tr
,_
le ro
10
AHG~
W AS HE R
re
ibrati
cr hav-
'"
.
11111
'"
'"
>r.;
ig
ra is even
'"
~,
:ilOO
ta
-,
80
c.z..
,...
en
cr
(tol ranc
/3
....
difference
re
(t l-
120
In the
60
ANGLE
HIoRO WIoSHER
20
100
et
cles the ighe
.J
rv
ic
ibrati
rodu
re
th
in
lu
ru pr
ably
ue to th ir larg it
15()
-:
10
im washer (B
F.
ig an
ibrati loosenin
angl
pr
uc (tra
versus preloa
vers
10/.
or
it -N
120
20
ractic ll ispl
t)
rt
in ri
tal; this ig
ra
are ns th ro
th
scre rg
it
328
10
" ", MI I. r . .
l W , . . - L : < - . - , - - ., ~.,lL~1 _II.
to
··-+--t--t+t-tttt 'i
'"
Numller
re
II
45
"'1lt
t._.u I:
10
100
1000
Nl; i t ! .
Cycles
.~t.~-
10
i\!UI
'~II
t-'-1·!t·;
1111 ; j
.. ~!::
-1,11\'1 "'"-
I:
,
'\-1
~
:
~
"l~!.~;~
-·n~~f'Jt I\.
Numhr
of Cycl..
A'J.'
,B
.S F-LOOSENrn
329
FASTENERS lots
rf
ll he
te
rd
isad antage
ints
th
te ti
rs 2cp/o
retain
tain
-N
rv
it
ig us be
that the maximum is
produc
lw
ecce tric te
lo
to th
pp ar
adjust
th
le els.
ra
re lt
il
re
ig
ible
th
(z ro lo
litude
t;4is vibration
it
the designer
iin
ants to
he will
applicatio
-FY-N urve at ig
8rJ1/o
er
al
s.
If
to
in
rotate fore
lo
vi-
the machine is
io ),
te ti
FY
th
rr sp ndin
during it proces
or severa
thre te
th
in
S-
bratio
relo
te this is on
proc dure just de crib
-N
curves
le
to be
dvantage us to
th
2r:P/o
E-FV-N
just described. this testin
method
.can
fastener curve.
Beside th
C: d~
(11)
re
ir
in tr
rg
le
it
th
ac in
re
to th
djuste
to
ir
ro uc
te in
le
ly entati
spring inni
advantag ri
li ie
It is
tory
th
tota re
rdin
th
nstant
this
pe ific l,
40
"'.
Jt ....
.. iIO_
~~
_fl.
:>-~
Emax, soft washer a r w as he r
20
0---"9--<;
mmKgfi_J
~l~l:-~tll II
0: 0..
_._--
10
rii~ ~ - - T
0:
10 Numhr
10
of
10
Number
1DOO
10
~-i~
f C
1000
100
Number of Cycles
T
T
.-,c.'_'.-,r.'.'
• • • • • _ ', ~ • • • , •• •N
G ER HA R
330
H.
U NK E
81
Ia.I
6~--+-~++HH--~~HH~~~>~ -0
£"'r---
r-
I---+--I--I+l-+Iifl-
----+-t-+t+H-lF-='"t-I--t-
_...
10
80%
t+t++H
1000
laO
10
100
1000
20"1.
50%
-,
:00:
10
1&
r-, r---
1'0: . . . . .
1---.
"""x
45
10
,..:.: 80",
~.!.UlL...
t----tI" ~x-
-to%. It
....... r - - -
c I -
-
+t
1000
---••
20%
•• ••
~T~_
II
.-
r-.. .
.
.
.
.
.
.
_,
,~
50
100
GoA-.!>
21
Ia.I
-'i44
lEIl
f-----.
f-_.
;;:_-
... ..
10
100
4Jl..
1000
Bl
SELF LOOSENINGOF PASTENERS ir
rg
le
rdin
.331
to th
ti
ro
rP\,
ju
\J
(12)
re
ig us be
achine
re
lt
in
ra le
th lo
tr
itti
th
tr
rs
rt
ro
if th
ib ti
th
differen
th
1:2
ri
ig
(d
th
forc /defle tion/displac
en
re
ridg
ir
rg
force/
ld
proc sses
plifier. ibrati
ro
responding to bridg
ts
ir
750/0
load of
processes. If
ta ts
th
tric
(13)
rg
in co parabl
:2
th th
leveb
ry
cycles.
re
rs
le
r-
2rP/o
amplifier. ro
in
ta
is as follows
rv
litu
achine to
of th vibratio
ri
deflection/displacemen
lo
-F-N
ta ts
te ts
constants in
rate
if re ri
re in th rati
re to
lo
8rP/o
te
re
term
Run
se is possible.
ft
. .
Fy.•
. -
. . ~ -
50%
80'4
10%
~x-x
'".:
......
-~
'\. t'---
-r II!
1.!.1
10
--
2011
0"':
21
r - - - . . ....
"',
1000
100
lOaD
II
1000
GE HA
332
H,
U NK E
EIN lOcp/o preloa
parts. despit
machin
ta da
their
components
prio to
pushpull fati ue te ts
The
difference
in
.in.)
(C lOcp/o pre-
this
FT
is
S;ELF-LOOSENIN
OF FASTENER
333
IO
methods.
ST PR GR
8fJI/Q.
in
5 C f 1 /o , 2 C f 1 o ) , In
(f).
this amplifier E- -N
is
is
establis
8 r F / o . 5 C f 1 / o . or 2 C f 1 / o
specified. It
be
is
tlu;ea:~~JfrlsertS or studs.
SUMMARY
is,
lo ct st
to rest rd te wash rs Infl ce f.th ea
to eran
Re sa iUty
in
fatigu
failur
If it
is
F V- N FT-
terial
movements
in
an structures
in
external thread). fo ce re la er
ments in
The
GE HA
334
H.
KE
ri ally, th be ev luated whic is lockin elementcauses parts.
:: Fricti.O ·diamete
the clamped
rg or transversel
on to nonlocking an
king
he
..bolt of bolt in ur ng
loaded joint
:: Energy absorbed by friction in
slidin
.mm kg Or in.r-l
the serr tion of
of
of
in. -lb
of nonlock-
he influenc
U'
:Sp
di
ng screws re
f"t.;
nc
ou
max
of
br on
or
or in.-lb :A
'F
um
max br on
the
ne
od
oa
8(J1/o
ur bl
fo
(E -N
ng pe fo
re
fa
:: es du clamping forc necessar fo main tainin gr friction of lamped compo-
be
ou
fo
:Tr as in
nc
d0 ments.
:Pr :::Workin
ACKNOWLEDGMENT
load in
:L
G. Meyer, Lab-Manage of SPS-UNBRAKO' European ED ro pe vi ng vo ou this paper,
gh
kg or
in. -lb
br on
SYMBOLSAND ABBREVIATIONS
pl FT
pl
on nt
pl
od
U- ha
nd
pe fo
nc
ng
pa
oefftcient of friction in thre ds
j.I::::
tan
.l
::::Amount of mbedding (Brine ing, "Setzen, pl on gh
E-F-
curves cycles.
ue
FT-
fr
ni components
pl
connections ra
FV-
gr
of
pe
335
SELF-LOOSENINGO FASTENERS REFERENCES
an Ho
to Preven it). mdustrie-Anzetger
7. di br tion
hreade
stenin s,
(Decembe
1945), 798-802.
echa ical
unke an
Haltbarkei
ngineering ic ll
Their
to Prevent
oosening."
achine
esig
vo
"Untersuchun en iibe di
Schraubenverbindunge
lastung" (I vestigatio amically
ad
Hannover
1966
olte
th
ic erungs i-
tion of
be dyna ischer
ocking
eature
on ections)
(N
of
is ertation
olte
9.
Sicherun th
chraubenverbindungen
is
olte
un di
lf-L
ri ci le
in
Connections)
DRAHT-
r. di
tu
zweckm~iBige Sicherun
(Aspects
elf- ooseni
onnections). 6.
ra
nd
as hinenm rkt,
unker, "Warum lose
zweckmii ig ti
),
Schraube
lb tati
rkt,
(1
ti
12
-N-5
ts
ocking of
IL
16
IL-F-1 24
lted
r. ·7
sich schraubenverbindunge
17
onne tions)
lf-l
in
°F. 250° ."
ibrati
-25027
lf-l
1200°F." IG."
Quality,"
in
"Nut self-locki g. "S lf-l ckin
250°
elemen
45 °F
fo fastener
50!'F."
I- 00 "Pre ailing-Tor ue
pe
te
exag
Locknuts." 18 1FI-101 "Torque-Tensio ilin 19
Requtrements
te .I -S
as
-2
"Nut self-l cking.
(A
1965
hr ubenberech un
olte
"N ts self-l cking.
15
Rules fo Calcula
de
r.
IL-N-78731
externally thre de
vo schraubenverbmdungen" 72 (1 66).
h-
-4
Usseldorf: Triltsch
rinzipie
ts
(1 ib
achb ilag r.
(Moder
lcul tion fo
in
elt. Fachbeilag
m: un
of
(Investigation of
in
io
raht-welt,
Connections)
-N-I
de selbsmitigen.Losen vo
oi ts),
iibe
Schraubenverbfrr
ig
rmte
nker "Neu
11 echani
th
atischen scbraubenberechnung"
land
genschafte
olte
tt rn
etrachtung
(Augus
1950), 133~139. 3.
ts
aded
"N uere
dyna isch belasteten
(N ra
Ho
vo
~Meyer
61(19'67).19-22:
-1312, "Fasteners
fo Pre-
ts es
th ds."
