How to Analyze Gear Failures
Content
How to analyze gear failures
By ROBERT L. ERRICHELLO and JANE MULLER of Geartech | Mar 1, !!! 1 "!! #M By fo$$o%&n' a (te)*+y*(te) )roced,re, en'&neer( can d&a'no(e 'ear fa&$,re( and de-e$o) (o$,t&on(. Here.( ho% to cond,ct a fa&$,re ana$y(&(, %hat to $oo/ for, and ho% to reco'n&0e co11on fa&$,re(
Article Tools
• • • • •
E1a&$ 2a-e #r&nt Re)r&nt
Popular Articles
• • • • • •
L,+r&cat&on t&)( for )$a(t&c 'ear( and 1ore Ba$$(cre%( -(. $ead (cre%( #er1anent*1a'net AC 1otor( Mot&on 2y(te1 3e(&'n * 4or )$ant en'&neer(, OEM en'&neer(, &nte'rator(, and (t,dent(. L&near 1ot&on En'&neer&n' +a(&c(
To o)t&1&0e the )erfor1ance of any ()eed red,cer, the 'ear( 1,(t +e or&ented to each other (o that they r,n (1ooth$y %&tho,t +&nd&n' or &nterference. They 1,(t a$(o 1a&nta&n the correct a1o,nt of tooth c$earance 5+ac/$a(h6 at a$$ o)erat&n' cond&t&on(. 4or (),r and he$&ca$ 'ear(, the +e(t or&entat&on nor1a$$y re7,&re( on$y that the center d&(tance and (haft a$&'n1ent +e correct 8 no f,rther ad9,(t1ent &( needed. Th&( &( (e$do1 the ca(e %&th +e-e$ 'ear(, %here 1o,nt&n' arran'e1ent( a$$o% for %&de -ar&at&on( &n )o(&t&on. A$$ ty)e( of +e-e$ 'ear( 8 (tra&'ht, :ero$, ()&ra$, and hy)o&d 8 ha-e an o)t&1,1 )o(&t&on for +e(t )erfor1ance. The 1an,fact,rer deter1&ne( th&( o)t&1,1 )o(&t&on +y r,nn&n' te(t( of &nd&-&d,a$ 'ear(et(. B,t, the 'ear+o; de(&'ner and a((e1+$y techn&c&an (hare the re()on(&+&$&ty for &ncor)orat&n' th&( o)t&1,1 )o(&t&on&n' &n the 'ear+o;. The de(&'ner 1,(t )ro-&de for ea(e of 1ea(,re1ent, (h&11&n', and a((e1+$y. And the techn&c&an 1,(t )ro)er$y a((e1+$e the 'ear( &n the 'ear+o;.
Key assembly parameters
2e-era$ )ara1eter( contr&+,te to )ro)er a((e1+$y (o that the 'ear+o; o)erate( (1ooth$y and eff&c&ent$y. The 1o(t &1)ortant are" < Mo,nt&n' d&(tance. < Matched teeth. < Bac/$a(h. Be-e$ 'ear( of AGMA 7,a$&ty = or +etter are nor1a$$y 1an,fact,red and te(ted &n (et(. Then, the 1an,fact,re 1ar/( the )referred -a$,e( for each of the three )ara1eter( on &nd&-&d,a$ 'ear(. 4re7,ent$y, the 1an,fact,rer a$(o 1ar/( a 'ear(et n,1+er on each of the t%o 'ear( &n a (et. Gear( 1an,fact,red &n (et( (ho,$d only +e a((e1+$ed %&th the&r 1ate(. 2&1&$ar$y, &f one 'ear &n a (et fa&$(, the ent&re (et (ho,$d +e re)$aced. Mounting distance. The d&(tance fro1 a $ocat&n' (,rface on the +ac/ of one 'ear to the center$&ne of a 1at&n' 'ear &( ca$$ed the 1o,nt&n' d&(tance, Figure 1.
Th&( &( the 1o(t &1)ortant )ara1eter for en(,r&n' )ro)er o)erat&on. The 1an,fact,rer e(ta+$&(he( the o)t&1,1 -a$,e for th&( d&(tance +y r,nn&n' the 'ear(et and ad9,(t&n' &t( )o(&t&on to o+ta&n a tooth contact )attern that &( con(&(tent %&th (1ooth r,nn&n' and o)t&1,1 $oad d&(tr&+,t&on +et%een 1at&n' 'ear teeth. Beca,(e of d&1en(&ona$ -ar&at&on( +et%een )art(, each 'ear &n a (et ha( a ,n&7,e -a$,e for the 1o,nt&n' d&(tance and, &n 1o(t ca(e(, the 1an,fact,rer )er1anent$y 1ar/( th&( -a$,e on each 'ear, Figure 2.
It &( )o((&+$e to 1an,fact,re a$$ 'ear( to the no1&na$ 1o,nt&n' d&(tance ()ec&f&ed on the dra%&n'. B,t, the add&t&ona$ co(t to do (o &( ,(,a$$y not %arranted. In ca(e( %here 1o,nt&n' d&(tance( ha-e not +een 1ar/ed on the 'ear(, a((e1+$y techn&c&an( 1,(t re(ort to a co(t$y tr&a$ and error 1ethod of 1ar/&n' teeth %&th 'ear co1)o,nd and ad9,(t&n' the 'ear( to o+ta&n a (,&ta+$e tooth contact )attern. The $ac/ of 1ar/ed -a$,e( 1ay a$(o &nd&cate that the 'ear(et %a( not 1an,fact,red for h&'h ca)ac&ty or con(&(tency. Matched teeth. After o)t&1,1 tooth contact &( o+ta&ned &n the r,nn&n' te(t(, the 1an,fact,rer 1ar/( 1at&n' teeth &n en'a'e1ent for &dent&f&cat&on. The(e 1ar/( ,(,a$$y con(&(t of ;.( or dot(, Figure 2, on t%o ad9acent teeth of one 'ear and the 1at&n' tooth of the other 'ear. >hen a((e1+$&n' the 'ear(et, )o(&t&on the (&n'$e 1ar/ed tooth &n the ()ace +et%een the t%o ad9acent 1ar/ed teeth. Backlash. The th&rd 1o(t &1)ortant )ara1eter for a +e-e$ 'ear(et &( the ()ace +et%een 1at&n' 'ear teeth, ca$$ed +ac/$a(h. Un$e(( other%&(e ()ec&f&ed, +ac/$a(h &( 1ea(,red nor1a$ 5)er)end&c,$ar6 to the tooth (,rface, Figure 3,
and not &n the )$ane of rotat&on. In 1o(t ca(e(, the 1an,fact,rer 1ar/( the nor1a$ +ac/$a(h -a$,e on the 'ear, Figure 2. Mea(,re1ent( &n the )$ane of rotat&on, ca$$ed tran(-er(e +ac/$a(h, are a( 1,ch a( ?!@ $ar'er, and (ho,$d not +e ,(ed for a((e1+$y ),r)o(e(. >here 1o,nt&n' d&(tance( ha-e +een 1ar/ed on one or +oth 'ear(, ad9,(t the(e d&(tance( f&r(t. Then, ,(e the nor1a$ +ac/$a(h -a$,e to -er&fy )ro)er a((e1+$y. The backlash value should not be measured until after assembling at least one of the two gears, preferably the pinion, at its marked mounting distance. The rea(on &( (&1)$e. Beca,(e +e-e$ 'ear( are con&ca$ &n (ha)e, they can +e a((e1+$ed &n an a$1o(t &nf&n&te n,1+er of )o(&t&on( 51o(t of %h&ch ca,(e )oor )erfor1ance6 and (t&$$ o+ta&n the re7,&red +ac/$a(h.
4re7,ent$y, a ca(,a$ ,(er a((e1+$e( +e-e$ 'ear( to o+ta&n a ()ec&f&c a1o,nt of +ac/$a(h %&tho,t re'ard to the 1o,nt&n' d&(tance. Th&( &( e()ec&a$$y tr,e for $o% 7,a$&ty or $&'ht$y* $oaded +e-e$ 'ear(. A$tho,'h th&( 1ethod occa(&ona$$y %or/(, &t &( a r&(/y a))roach %here 'ear( are $oaded to 1a;&1,1 ca)ac&ty. It ,(,a$$y ca,(e( (horter $&fe and )oor )erfor1ance. On$y at the )ro)er 1o,nt&n' d&(tance %&$$ a 'ear(et r,n correct$y and (t&$$ ha-e the r&'ht a1o,nt of +ac/$a(h.
ear assembly
In 1o(t +e-e$ 'ear(et(, )art&c,$ar$y tho(e %&th rat&o( a+o-e "1, the )&n&on )o(&t&on 51o,nt&n' d&(tance6 effect( tooth contact 5the 1o(t &1)ortant )ara1eter for 'ood )erfor1ance6 to a $ar'er e;tent than the 'ear )o(&t&on. Con-er(e$y, the 'ear )o(&t&on ha( a $ar'er effect on +ac/$a(h. 4or th&( rea(on, the 1an,fact,rer 1ay ha-e 1ar/ed the 1o,nt&n' d&(tance on$y on the )&n&on. In (,ch ca(e(, +e (,re to acc,rate$y )o(&t&on the )&n&on accord&n' to &t( 1ar/ed 1o,nt&n' d&(tance +efore ad9,(t&n' +ac/$a(h. Th&( can +e acco1)$&(hed e&ther +y 'a'&n' or +y d&rect 1ea(,re1ent. Ga'e( are ,(ed 1o(t$y for $ar'e 'ear )rod,ct&on r,n(, and are +a(ed on the d&rect 1ea(,re1ent 1ethod. 4or th&( rea(on, on$y the 1ea(,re1ent 1ethod &( de(cr&+ed here. Note that %hen 1at&n' 'ear( are ad9,(ted to the&r o)t&1,1 )o(&t&on, the&r +ac/ an'$e(, Figure 1, %&$$ )ro+a+$y not +e f$,(h %&th each other. Do not attempt to position bevel gears by making the back angles flush.
Measurement method. A ty)&ca$ 'ear+o;, Figure ,
conta&n( +oth an o-erh,n' and a (tradd$e*1o,nted 'ear. The )roced,re for a((e1+$&n' the +e-e$ 'ear( &n th&( 'ear+o; +y the 1ea(,re1ent 1ethod &( (&1)$e" < On the ho,(&n', 1ea(,re the d&(tance fro1 $ocat&n' (,rface to +ore center$&ne &n +oth hor&0onta$ and -ert&ca$ d&rect&on( 5HM3 and AM36. < Record the 'ear and )&n&on 1o,nt&n' d&(tance( 5M3G and M3#6. < Mea(,re the 'ear and )&n&on th&c/ne((e( 5>G and >#6. < A((e1+$e the 'ear( &nto the&r (,+a((e1+$&e(. < Mea(,re the $en'th that contro$( 'ear )o(&t&on &n each (,+a((e1+$y 5MAG and MA#6. < Ca$c,$ate the d&(tance fro1 (h&1 1o,nt&n' (,rface to cro((&n' )o&nt for each (,+a((e1+$y 5M3A and M3H6. < Ca$c,$ate the re7,&red (h&1 th&c/ne((e( and a((e1+$e the 'ear+o; %&th (h&1( &n )$ace. To a&d the a((e1+$y techn&c&an, 1ar/ the ho,(&n' 1ea(,re1ent( on the ho,(&n' after &t &( 1ach&ned and &n()ected. Mea(,re1ent( &n-o$-&n' the )&n&on and 'ear are ta/en on the (,+a((e1+$&e(, %h&ch con(&(t of 'ear, (haft, +ear&n', and 'ear 1o,nt&n' co1)onent(. Th&( 1&n&1&0e( any -ar&at&on( d,e to f&t( +et%een the(e co1)onent( and 'reat$y red,ce( the n,1+er of 1ea(,re1ent( re7,&red. In th&( e;a1)$e, on$y the 'ear th&c/ne(( &( 1ea(,red +efore ),tt&n' to'ether the (,+a((e1+$y. 2,+tract&n' th&( d&(tance fro1 the 1o,nt&n' d&(tance $et( the techn&c&an 1ea(,re fro1 the front of the a((e1+$ed 'ear. !erifying proper assembly. U(e the 1ea(,re1ent 1ethod to a((e1+$e +oth 'ear(, 1a/&n' (,re that the 1atched teeth are )ro)er$y en'a'ed. On$y after )o(&t&on&n' +oth 'ear( at the&r 1o,nt&n' d&(tance( (ho,$d yo, 1ea(,re +ac/$a(h to -er&fy )ro)er a((e1+$y. In ca(e( %here on$y the )&n&on &( 1ar/ed %&th a 1o,nt&n' d&(tance, )o(&t&on the )&n&on at &t( 1o,nt&n' d&(tance f&r(t, then ad9,(t the 'ear )o(&t&on for the re7,&red +ac/$a(h.
To o+ta&n f,rther -er&f&cat&on, yo, can )erfor1 an o)t&ona$ contact )attern chec/. Th&( &n-o$-e( )a&nt&n' the tooth (,rface( on one 'ear %&th a th&n 1ar/&n' co1)o,nd and rotat&n' the a((e1+$ed 'ear( ,nder $&'ht $oad. The co1)o,nd tran(fer( fro1 one 'ear to the other and (ho%( ho% the teeth contact. N,1ero,( ),+$&cat&on( conta&n chart( %&th ty)&ca$ contact )attern( 5AN2IBAGMA !!=*BC! and AN2IBAGMA !!D*B==6. The )attern( (e$do1 $oo/ e;act$y $&/e the ),+$&(hed e;a1)$e( and fre7,ent$y re7,&re (o1e &nter)retat&on. Techn&c&an( fa1&$&ar %&th contact )attern chec/&n' 1ay +e$&e-e that th&( techn&7,e &( the )referred 1ethod of a((e1+$y. Ho%e-er, the 1an,fact,rer ha( a$ready )erfor1ed th&( chec/ a( )art of the te(t&n' 5to deter1&ne 1o,nt&n' d&1en(&on(6 and &nter)reted the contact )attern( (o yo, don.t ha-e to. Robert F. Wasilewski is the design engineering manager for !rrow "ear #o., Downers "rove, $ll.
By ROBERT L. ERRICHELLO and JANE MULLER of Geartech | Mar 1, !!! 1 "!! #M By fo$$o%&n' a (te)*+y*(te) )roced,re, en'&neer( can d&a'no(e 'ear fa&$,re( and de-e$o) (o$,t&on(. Here.( ho% to cond,ct a fa&$,re ana$y(&(, %hat to $oo/ for, and ho% to reco'n&0e co11on fa&$,re(
Article Tools
• • • • •
E1a&$ 2a-e #r&nt Re)r&nt
Popular Articles
• • • • • •
L,+r&cat&on t&)( for )$a(t&c 'ear( and 1ore Ba$$(cre%( -(. $ead (cre%( #er1anent*1a'net AC 1otor( Mot&on 2y(te1 3e(&'n * 4or )$ant en'&neer(, OEM en'&neer(, &nte'rator(, and (t,dent(. L&near 1ot&on En'&neer&n' +a(&c(
To o)t&1&0e the )erfor1ance of any ()eed red,cer, the 'ear( 1,(t +e or&ented to each other (o that they r,n (1ooth$y %&tho,t +&nd&n' or &nterference. They 1,(t a$(o 1a&nta&n the correct a1o,nt of tooth c$earance 5+ac/$a(h6 at a$$ o)erat&n' cond&t&on(. 4or (),r and he$&ca$ 'ear(, the +e(t or&entat&on nor1a$$y re7,&re( on$y that the center d&(tance and (haft a$&'n1ent +e correct 8 no f,rther ad9,(t1ent &( needed. Th&( &( (e$do1 the ca(e %&th +e-e$ 'ear(, %here 1o,nt&n' arran'e1ent( a$$o% for %&de -ar&at&on( &n )o(&t&on. A$$ ty)e( of +e-e$ 'ear( 8 (tra&'ht, :ero$, ()&ra$, and hy)o&d 8 ha-e an o)t&1,1 )o(&t&on for +e(t )erfor1ance. The 1an,fact,rer deter1&ne( th&( o)t&1,1 )o(&t&on +y r,nn&n' te(t( of &nd&-&d,a$ 'ear(et(. B,t, the 'ear+o; de(&'ner and a((e1+$y techn&c&an (hare the re()on(&+&$&ty for &ncor)orat&n' th&( o)t&1,1 )o(&t&on&n' &n the 'ear+o;. The de(&'ner 1,(t )ro-&de for ea(e of 1ea(,re1ent, (h&11&n', and a((e1+$y. And the techn&c&an 1,(t )ro)er$y a((e1+$e the 'ear( &n the 'ear+o;.
Key assembly parameters
2e-era$ )ara1eter( contr&+,te to )ro)er a((e1+$y (o that the 'ear+o; o)erate( (1ooth$y and eff&c&ent$y. The 1o(t &1)ortant are" < Mo,nt&n' d&(tance. < Matched teeth. < Bac/$a(h. Be-e$ 'ear( of AGMA 7,a$&ty = or +etter are nor1a$$y 1an,fact,red and te(ted &n (et(. Then, the 1an,fact,re 1ar/( the )referred -a$,e( for each of the three )ara1eter( on &nd&-&d,a$ 'ear(. 4re7,ent$y, the 1an,fact,rer a$(o 1ar/( a 'ear(et n,1+er on each of the t%o 'ear( &n a (et. Gear( 1an,fact,red &n (et( (ho,$d only +e a((e1+$ed %&th the&r 1ate(. 2&1&$ar$y, &f one 'ear &n a (et fa&$(, the ent&re (et (ho,$d +e re)$aced. Mounting distance. The d&(tance fro1 a $ocat&n' (,rface on the +ac/ of one 'ear to the center$&ne of a 1at&n' 'ear &( ca$$ed the 1o,nt&n' d&(tance, Figure 1.
Th&( &( the 1o(t &1)ortant )ara1eter for en(,r&n' )ro)er o)erat&on. The 1an,fact,rer e(ta+$&(he( the o)t&1,1 -a$,e for th&( d&(tance +y r,nn&n' the 'ear(et and ad9,(t&n' &t( )o(&t&on to o+ta&n a tooth contact )attern that &( con(&(tent %&th (1ooth r,nn&n' and o)t&1,1 $oad d&(tr&+,t&on +et%een 1at&n' 'ear teeth. Beca,(e of d&1en(&ona$ -ar&at&on( +et%een )art(, each 'ear &n a (et ha( a ,n&7,e -a$,e for the 1o,nt&n' d&(tance and, &n 1o(t ca(e(, the 1an,fact,rer )er1anent$y 1ar/( th&( -a$,e on each 'ear, Figure 2.
It &( )o((&+$e to 1an,fact,re a$$ 'ear( to the no1&na$ 1o,nt&n' d&(tance ()ec&f&ed on the dra%&n'. B,t, the add&t&ona$ co(t to do (o &( ,(,a$$y not %arranted. In ca(e( %here 1o,nt&n' d&(tance( ha-e not +een 1ar/ed on the 'ear(, a((e1+$y techn&c&an( 1,(t re(ort to a co(t$y tr&a$ and error 1ethod of 1ar/&n' teeth %&th 'ear co1)o,nd and ad9,(t&n' the 'ear( to o+ta&n a (,&ta+$e tooth contact )attern. The $ac/ of 1ar/ed -a$,e( 1ay a$(o &nd&cate that the 'ear(et %a( not 1an,fact,red for h&'h ca)ac&ty or con(&(tency. Matched teeth. After o)t&1,1 tooth contact &( o+ta&ned &n the r,nn&n' te(t(, the 1an,fact,rer 1ar/( 1at&n' teeth &n en'a'e1ent for &dent&f&cat&on. The(e 1ar/( ,(,a$$y con(&(t of ;.( or dot(, Figure 2, on t%o ad9acent teeth of one 'ear and the 1at&n' tooth of the other 'ear. >hen a((e1+$&n' the 'ear(et, )o(&t&on the (&n'$e 1ar/ed tooth &n the ()ace +et%een the t%o ad9acent 1ar/ed teeth. Backlash. The th&rd 1o(t &1)ortant )ara1eter for a +e-e$ 'ear(et &( the ()ace +et%een 1at&n' 'ear teeth, ca$$ed +ac/$a(h. Un$e(( other%&(e ()ec&f&ed, +ac/$a(h &( 1ea(,red nor1a$ 5)er)end&c,$ar6 to the tooth (,rface, Figure 3,
and not &n the )$ane of rotat&on. In 1o(t ca(e(, the 1an,fact,rer 1ar/( the nor1a$ +ac/$a(h -a$,e on the 'ear, Figure 2. Mea(,re1ent( &n the )$ane of rotat&on, ca$$ed tran(-er(e +ac/$a(h, are a( 1,ch a( ?!@ $ar'er, and (ho,$d not +e ,(ed for a((e1+$y ),r)o(e(. >here 1o,nt&n' d&(tance( ha-e +een 1ar/ed on one or +oth 'ear(, ad9,(t the(e d&(tance( f&r(t. Then, ,(e the nor1a$ +ac/$a(h -a$,e to -er&fy )ro)er a((e1+$y. The backlash value should not be measured until after assembling at least one of the two gears, preferably the pinion, at its marked mounting distance. The rea(on &( (&1)$e. Beca,(e +e-e$ 'ear( are con&ca$ &n (ha)e, they can +e a((e1+$ed &n an a$1o(t &nf&n&te n,1+er of )o(&t&on( 51o(t of %h&ch ca,(e )oor )erfor1ance6 and (t&$$ o+ta&n the re7,&red +ac/$a(h.
4re7,ent$y, a ca(,a$ ,(er a((e1+$e( +e-e$ 'ear( to o+ta&n a ()ec&f&c a1o,nt of +ac/$a(h %&tho,t re'ard to the 1o,nt&n' d&(tance. Th&( &( e()ec&a$$y tr,e for $o% 7,a$&ty or $&'ht$y* $oaded +e-e$ 'ear(. A$tho,'h th&( 1ethod occa(&ona$$y %or/(, &t &( a r&(/y a))roach %here 'ear( are $oaded to 1a;&1,1 ca)ac&ty. It ,(,a$$y ca,(e( (horter $&fe and )oor )erfor1ance. On$y at the )ro)er 1o,nt&n' d&(tance %&$$ a 'ear(et r,n correct$y and (t&$$ ha-e the r&'ht a1o,nt of +ac/$a(h.
ear assembly
In 1o(t +e-e$ 'ear(et(, )art&c,$ar$y tho(e %&th rat&o( a+o-e "1, the )&n&on )o(&t&on 51o,nt&n' d&(tance6 effect( tooth contact 5the 1o(t &1)ortant )ara1eter for 'ood )erfor1ance6 to a $ar'er e;tent than the 'ear )o(&t&on. Con-er(e$y, the 'ear )o(&t&on ha( a $ar'er effect on +ac/$a(h. 4or th&( rea(on, the 1an,fact,rer 1ay ha-e 1ar/ed the 1o,nt&n' d&(tance on$y on the )&n&on. In (,ch ca(e(, +e (,re to acc,rate$y )o(&t&on the )&n&on accord&n' to &t( 1ar/ed 1o,nt&n' d&(tance +efore ad9,(t&n' +ac/$a(h. Th&( can +e acco1)$&(hed e&ther +y 'a'&n' or +y d&rect 1ea(,re1ent. Ga'e( are ,(ed 1o(t$y for $ar'e 'ear )rod,ct&on r,n(, and are +a(ed on the d&rect 1ea(,re1ent 1ethod. 4or th&( rea(on, on$y the 1ea(,re1ent 1ethod &( de(cr&+ed here. Note that %hen 1at&n' 'ear( are ad9,(ted to the&r o)t&1,1 )o(&t&on, the&r +ac/ an'$e(, Figure 1, %&$$ )ro+a+$y not +e f$,(h %&th each other. Do not attempt to position bevel gears by making the back angles flush.
Measurement method. A ty)&ca$ 'ear+o;, Figure ,
conta&n( +oth an o-erh,n' and a (tradd$e*1o,nted 'ear. The )roced,re for a((e1+$&n' the +e-e$ 'ear( &n th&( 'ear+o; +y the 1ea(,re1ent 1ethod &( (&1)$e" < On the ho,(&n', 1ea(,re the d&(tance fro1 $ocat&n' (,rface to +ore center$&ne &n +oth hor&0onta$ and -ert&ca$ d&rect&on( 5HM3 and AM36. < Record the 'ear and )&n&on 1o,nt&n' d&(tance( 5M3G and M3#6. < Mea(,re the 'ear and )&n&on th&c/ne((e( 5>G and >#6. < A((e1+$e the 'ear( &nto the&r (,+a((e1+$&e(. < Mea(,re the $en'th that contro$( 'ear )o(&t&on &n each (,+a((e1+$y 5MAG and MA#6. < Ca$c,$ate the d&(tance fro1 (h&1 1o,nt&n' (,rface to cro((&n' )o&nt for each (,+a((e1+$y 5M3A and M3H6. < Ca$c,$ate the re7,&red (h&1 th&c/ne((e( and a((e1+$e the 'ear+o; %&th (h&1( &n )$ace. To a&d the a((e1+$y techn&c&an, 1ar/ the ho,(&n' 1ea(,re1ent( on the ho,(&n' after &t &( 1ach&ned and &n()ected. Mea(,re1ent( &n-o$-&n' the )&n&on and 'ear are ta/en on the (,+a((e1+$&e(, %h&ch con(&(t of 'ear, (haft, +ear&n', and 'ear 1o,nt&n' co1)onent(. Th&( 1&n&1&0e( any -ar&at&on( d,e to f&t( +et%een the(e co1)onent( and 'reat$y red,ce( the n,1+er of 1ea(,re1ent( re7,&red. In th&( e;a1)$e, on$y the 'ear th&c/ne(( &( 1ea(,red +efore ),tt&n' to'ether the (,+a((e1+$y. 2,+tract&n' th&( d&(tance fro1 the 1o,nt&n' d&(tance $et( the techn&c&an 1ea(,re fro1 the front of the a((e1+$ed 'ear. !erifying proper assembly. U(e the 1ea(,re1ent 1ethod to a((e1+$e +oth 'ear(, 1a/&n' (,re that the 1atched teeth are )ro)er$y en'a'ed. On$y after )o(&t&on&n' +oth 'ear( at the&r 1o,nt&n' d&(tance( (ho,$d yo, 1ea(,re +ac/$a(h to -er&fy )ro)er a((e1+$y. In ca(e( %here on$y the )&n&on &( 1ar/ed %&th a 1o,nt&n' d&(tance, )o(&t&on the )&n&on at &t( 1o,nt&n' d&(tance f&r(t, then ad9,(t the 'ear )o(&t&on for the re7,&red +ac/$a(h.
To o+ta&n f,rther -er&f&cat&on, yo, can )erfor1 an o)t&ona$ contact )attern chec/. Th&( &n-o$-e( )a&nt&n' the tooth (,rface( on one 'ear %&th a th&n 1ar/&n' co1)o,nd and rotat&n' the a((e1+$ed 'ear( ,nder $&'ht $oad. The co1)o,nd tran(fer( fro1 one 'ear to the other and (ho%( ho% the teeth contact. N,1ero,( ),+$&cat&on( conta&n chart( %&th ty)&ca$ contact )attern( 5AN2IBAGMA !!=*BC! and AN2IBAGMA !!D*B==6. The )attern( (e$do1 $oo/ e;act$y $&/e the ),+$&(hed e;a1)$e( and fre7,ent$y re7,&re (o1e &nter)retat&on. Techn&c&an( fa1&$&ar %&th contact )attern chec/&n' 1ay +e$&e-e that th&( techn&7,e &( the )referred 1ethod of a((e1+$y. Ho%e-er, the 1an,fact,rer ha( a$ready )erfor1ed th&( chec/ a( )art of the te(t&n' 5to deter1&ne 1o,nt&n' d&1en(&on(6 and &nter)reted the contact )attern( (o yo, don.t ha-e to. Robert F. Wasilewski is the design engineering manager for !rrow "ear #o., Downers "rove, $ll.
