Nres pads yog qhov tseem ceeb tshaj plaws ntawm kev nyab xeeb hauv lub tshuab nres, uas ua lub luag haujlwm txiav txim siab ntawm qhov zoo ntawm cov nyhuv nres, thiab lub nres nres zoo yog tus tiv thaiv tib neeg thiab tsheb (aircraft).
Ua ntej, lub hauv paus chiv keeb ntawm cov pawm nres
Xyoo 1897, HerbertFrood tau tsim thawj lub tshuab nres tsheb (siv cov xov paj rwb ua cov fiber ntau ntxiv) thiab siv rau hauv cov tsheb thauj neeg caij nees thiab tsheb thaum ntxov, los ntawm lub tuam txhab nto moo Ferodo tau tsim. Tom qab ntawd xyoo 1909, lub tuam txhab tau tsim lub ntiaj teb thawj zaug ua kom muaj zog asbestos-raws li nres nres; Nyob rau hauv 1968, lub ntiaj teb thawj ib nrab-hlau-raws li brake pads tau tsim, thiab txij thaum ntawd los, cov ntaub ntawv sib txhuam tau pib tsim mus rau asbestos-dawb. Hauv tsev thiab txawv teb chaws pib kawm ntau yam asbestos hloov fibers xws li steel fiber, iav fiber, aramid fiber, carbon fiber thiab lwm yam kev siv hauv cov ntaub ntawv sib txhuam.
Thib ob, kev faib tawm ntawm cov pawm nres
Muaj ob txoj hauv kev los faib cov khoom siv nres. Ib qho yog muab faib los ntawm kev siv cov koom haum. Xws li tsheb nres cov ntaub ntawv, tsheb ciav hlau cov ntaub ntawv thiab aviation nres cov ntaub ntawv. Txoj kev faib yog yooj yim thiab yooj yim to taub. Ib qho yog muab faib raws li cov khoom siv. Qhov kev faib tawm no yog kev tshawb fawb ntau dua. Cov khoom siv nres niaj hnub no feem ntau suav nrog peb pawg hauv qab no: cov khoom siv nres tsheb (asbestos nres cov ntaub ntawv, cov ntaub ntawv tsis yog asbestos, cov ntaub ntawv nres tsheb), hmoov hlau metallurgy nres cov ntaub ntawv, carbon / carbon composite brake cov ntaub ntawv thiab ceramic raws li cov ntaub ntawv nres.
Thib peb, tsheb nres cov ntaub ntawv
1, hom tsheb nres cov ntaub ntawv raws li kev tsim khoom sib txawv. Nws tuaj yeem muab faib ua cov ntawv asbestos, cov ntawv ib nrab lossis cov ntawv hlau tsawg, NAO (asbestos dawb organic teeb meem) daim ntawv, cov ntawv carbon carbon thiab cov ntawv ceramic.
1.1.Asbestos ntawv
Txij li thaum pib, asbestos tau siv los ua cov khoom siv txhawb zog rau cov ntaub qhwv, vim tias cov asbestos fiber ntau muaj zog thiab kub tsis kam, yog li nws tuaj yeem ua tau raws li qhov yuav tsum tau muaj ntawm cov brakes thiab clutch discs thiab gaskets. Cov fiber ntau no muaj zog tensile muaj peev xwm, tuaj yeem sib tw qib high-qib steel, thiab tuaj yeem tiv taus qhov kub thiab txias ntawm 316 ° C. Dab tsi ntxiv, asbestos kuj pheej yig. Nws yog muab rho tawm los ntawm amphibole ore, uas muaj nyob rau hauv ntau ntau nyob rau hauv ntau lub teb chaws. Asbestos kev sib txhuam cov ntaub ntawv tsuas yog siv asbestos fiber ntau, uas yog hydrated magnesium silicate (3MgO·2SiO2·2H2O) ua fiber ntau. Ib tug muab tub lim rau kho cov khoom sib txhuam yog ntxiv. Ib qho organic matrix composite khoom yog tau los ntawm nias lub nplaum nyob rau hauv ib tug kub xovxwm pwm.
Ua ntej xyoo 1970. Asbestos hom kev sib txhuam yog siv dav hauv ntiaj teb. Thiab dominated rau lub sij hawm ntev. Txawm li cas los xij, vim qhov tsis zoo ntawm kev hloov pauv cua sov ntawm asbestos. Kev sib txhuam kub tsis tuaj yeem dissipated sai. Nws yuav ua rau lub thermal decay txheej ntawm kev sib txhuam nto kom thicken. Ua kom cov khoom hnav. Lub sijhawm no. Cov dej siv lead ua ntawm asbestos fiber ntau yog precipitated saum 400 ℃. Cov cuab yeej kev sib txhuam yog txo qis thiab qhov hnav tau nce siab thaum nws nce mus txog 550 ℃ lossis ntau dua. Cov dej siv lead ua tau poob ntau heev. Kev txhim kho yog ploj tag. Tseem ceeb dua. Nws yog kev kho mob pov thawj. Asbestos yog ib yam khoom uas muaj kev puas tsuaj loj rau tib neeg cov kab mob ua pa. Lub Xya Hli 1989. Lub Koom Haum Saib Xyuas Kev Tiv Thaiv Ib puag ncig hauv Teb Chaws Asmeskas (EPA) tshaj tawm tias nws yuav txwv tsis pub ntshuam, tsim khoom, thiab ua txhua yam khoom siv asbestos los ntawm 1997.
1.2, semi-hlau ntawv
Nws yog ib hom tshiab ntawm kev sib txhuam cov khoom tsim los ntawm cov khoom siv sib txhuam organic thiab cov khoom siv tshuaj txhuam cov hmoov metallurgy. Nws siv cov hlau fibers tsis yog asbestos fibers. Nws yog cov khoom siv tsis sib haum asbestos tsim los ntawm American Bendis Company thaum xyoo 1970s.
"Semi-hlau" hybrid nres pads (Semi-metal) yog tsim los ntawm cov ntaub plaub hlau ntxhib ua ib qho kev txhawb zog fiber ntau thiab ib qho tseem ceeb sib xyaw. Asbestos thiab non-asbestos organic brake pads (NAO) tuaj yeem paub qhov txawv ntawm qhov pom tau yooj yim (zoo fibers thiab hais), thiab lawv kuj muaj qee yam khoom sib nqus.
Semi-metallic sib txhuam cov ntaub ntawv muaj cov yam ntxwv tseem ceeb hauv qab no:
(l) ruaj khov heev hauv qab coefficient ntawm kev sib txhuam. Tsis tsim thermal decay. Zoo thermal stability;
(2) Zoo hnav tsis kam. Lub neej kev pab cuam yog 3-5 npaug ntawm cov ntaub ntawv sib txhuam asbestos;
(3) Kev sib txhuam zoo ua haujlwm nyob rau hauv siab load thiab ruaj khov kev sib txhuam coefficient;
(4) Zoo thermal conductivity. Qhov kub gradient me me. Tshwj xeeb tshaj yog tsim rau me me disc nres khoom;
(5) me me braking nrov.
Tebchaws Asmeskas, Europe, Nyiv thiab lwm lub tebchaws tau pib txhawb kev siv thaj chaw loj hauv xyoo 1960. Kev hnav tsis kam ntawm cov ntawv semi-hlau yog ntau dua 25% siab dua li ntawm cov ntawv asbestos. Tam sim no, nws tuav txoj haujlwm tseem ceeb hauv kev lag luam nres nres hauv Suav teb. Thiab feem ntau cov tsheb Asmeskas. Tshwj xeeb yog tsheb thiab cov neeg caij tsheb thiab cov tsheb thauj khoom. Semi-hlau nres hauv ob sab phlu tau suav txog ntau dua 80%.
Txawm li cas los xij, cov khoom tseem muaj cov nram qab no shortcomings:
(l) Hlau fiber ntau yog yooj yim rau xeb, yooj yim rau lo los yog ua puas lub khub tom qab xeb, thiab lub zog ntawm cov khoom yog txo tom qab xeb, thiab hnav yog nce;
(2) High thermal conductivity, uas yog ib qho yooj yim ua rau lub nres system tsim cov roj tsis kam ntawm qhov kub thiab txias, ua rau cov txheej txheem sib txhuam thiab cov hlau phaj detachment:
(3) Lub hardness siab yuav ua rau cov khoom siv dual puas, ua rau muaj kev sib tham thiab tsis tshua muaj suab nrov;
(4) High ceev.
Txawm hais tias "semi-hlau" tsis muaj qhov tsis zoo me me, tab sis vim nws cov khoom ruaj khov zoo, tus nqi qis, nws tseem yog cov khoom siv rau tsheb nres tsheb.
1.3. NAO film
Thaum xyoo 1980s, muaj ntau yam hybrid fiber reinforced asbestos-free brake linings nyob rau hauv lub ntiaj teb no, uas yog, peb tiam ntawm asbestos-dawb organic teeb meem NAO hom nres pads. Nws lub hom phiaj yog los tsim kom muaj qhov tsis xws luag ntawm cov hlau fiber ntau ib qho khoom siv hluav taws xob semi-metallic nres, cov fibers siv yog cog fiber ntau, aramong fiber, iav fiber ntau, ceramic fiber, carbon fiber, ntxhia fiber ntau thiab lwm yam. Vim hais tias ntawm daim ntawv thov ntawm ntau fibers, cov fibers nyob rau hauv lub brake hauv ob sab phlu complements ib leeg nyob rau hauv kev ua tau zoo, thiab nws yog ib qho yooj yim los tsim tus brake hauv ob sab phlu qauv nrog zoo heev kev ua tau zoo. Lub ntsiab kom zoo dua ntawm NAO daim ntawv yog tswj kom zoo braking nyhuv ntawm qis los yog siab kub, txo hnav, txo suab nrov, thiab ncua lub neej kev pab cuam ntawm lub nres disc, sawv cev rau tam sim no txoj kev loj hlob kev taw qhia ntawm kev sib txhuam cov ntaub ntawv. Cov khoom siv sib txhuam siv los ntawm tag nrho lub ntiaj teb nto moo hom ntawm Benz / Philodo brake pads yog lub thib peb-tiam NAO asbestos-dawb organic khoom, uas tuaj yeem nres dawb ntawm txhua qhov kub, tiv thaiv lub neej ntawm tus neeg tsav tsheb, thiab ua kom lub neej ntev ntawm lub nres. disc.
1.4, carbon daim ntawv
Cov pa roj carbon fiber ntau cov khoom sib txhuam yog ib yam khoom siv nrog carbon fiber reinforced carbon matrix. Nws cov khoom frictional zoo heev. Tsawg ceev (tsuas yog hlau); Qib siab muaj peev xwm. Nws muaj peev xwm ua kom sov ntau dua li cov khoom siv hmoov metallurgy thiab hlau; High kub siv; Tsis muaj deformation, adhesion tshwm sim. Ua haujlwm kub txog 200 ℃; Kev sib txhuam zoo thiab hnav ua haujlwm. Lub neej ua haujlwm ntev. Kev sib txhuam coefficient yog ruaj khov thiab nruab nrab thaum lub sijhawm braking. Carbon-carbon composite sheets yog thawj zaug siv hauv cov tub rog dav hlau. Tom qab ntawd nws tau txais kev pom zoo los ntawm Formula 1 cov tsheb sib tw, uas tsuas yog siv cov pa roj carbon cov ntaub ntawv hauv tsheb nres tsheb.
Cov pa roj carbon monoxide cov khoom sib txhuam yog cov khoom siv tshwj xeeb nrog thermal stability, hnav tsis kam, hluav taws xob conductivity, lub zog tshwj xeeb, elasticity thiab ntau lwm yam ntxwv. Txawm li cas los xij, cov khoom siv sib xyaw carbon-carbon sib xyaw kuj muaj qhov tsis zoo hauv qab no: kev sib txhuam coefficient tsis ruaj khov. Nws cuam tshuam zoo heev los ntawm cov av noo;
Tsis zoo oxidation tsis kam (hnyav oxidation tshwm sim saum 50 ° C hauv huab cua). Kev xav tau siab rau ib puag ncig (qhuav, huv si); Nws kim heev. Kev siv tsuas yog siv rau thaj chaw tshwj xeeb. Qhov no kuj yog vim li cas tseem ceeb vim li cas kev txwv cov khoom siv carbon yog qhov nyuaj rau kev nthuav dav.
1.5, ceramic pieces
Raws li cov khoom tshiab hauv cov ntaub ntawv sib txhuam. Ceramic brake pads muaj qhov zoo ntawm tsis muaj suab nrov, tsis muaj tshauv poob, tsis muaj corrosion ntawm lub log hub, kev pab lub neej ntev, kev tiv thaiv ib puag ncig thiab lwm yam. Ceramic brake pads yog thawj zaug tsim los ntawm cov tuam txhab Japanese nres tsheb hauv xyoo 1990. Maj mam dhau los ua tus tshiab darling ntawm lub lag luam nres nres.
Cov neeg sawv cev ntawm cov khoom siv sib txhuam ceramic yog C / C-sic composites, uas yog, carbon fiber reinforced silicon carbide matrix C / SiC composites. Cov kws tshawb fawb los ntawm University of Stuttgart thiab German Aerospace Research Institute tau kawm txog daim ntawv thov ntawm C / C-sic composites hauv kev sib txhuam, thiab tsim C / C-SIC brakes rau siv hauv Porsche tsheb. Oak Ridge National Laboratory nrog Honeywell Advnanced composites, HoneywellAireratf Lnading Systems, thiab Honeywell CommercialVehicle systems Lub tuam txhab tab tom ua hauj lwm ua ke los tsim cov nqi qis C/SiC composite brake pads los hloov cam khwb cia hlau thiab cam khwb cia hlau nres pads siv nyob rau hauv hnyav-duty tsheb.
2, carbon ceramic composite nres ncoo zoo:
1, piv nrog cov tsoos grey cam khwb cia hlau nres ncoo, qhov hnyav ntawm cov pa roj carbon ceramic nres yog txo los ntawm li 60%, thiab qhov hnyav tsis raug ncua yog txo los ntawm ze li ntawm 23 kilograms;
2, tus nres kev sib txhuam coefficient muaj qhov nce siab heev, tus nres nres ceev yog nce thiab nres attenuation txo;
3, tensile elongation ntawm cov khoom siv ceramic yog li ntawm 0.1% txog 0.3%, uas yog tus nqi siab heev rau cov khoom siv ceramic;
4, Ceramic disc pedal hnov zoo heev, tuaj yeem tsim lub zog siab tshaj plaws hauv lub sijhawm pib ntawm kev sib tsoo, yog li tsis tas yuav ua kom lub zog pab nres, thiab tag nrho braking yog sai dua thiab luv dua li cov tsoos braking system. ;
5, nyob rau hauv thiaj li yuav tiv thaiv kub kub, muaj ceramic tshav kub rwb thaiv tsev ntawm tus nres piston thiab lub nres liner;
6, ceramic nres disc muaj qhov ua tau zoo tshaj plaws, yog tias kev siv ib txwm muaj lub neej hloov pauv, thiab cov cam khwb cia hlau nres disc feem ntau yog siv rau ob peb xyoos los hloov.
Post lub sij hawm: Sep-08-2023