Chifukwa Chake Mainjiniya Amasankha Sintered Bearings: The Powder Metallurgy Advantage

Sayansi Pambuyo pa Sintered Bronze Bearings

 

Sayansi yopangira zinthu zokhala ndi sintered bronze zimadalira kuwongolera kwachitsulo komwe kumasintha tinthu tating'onoting'ono tachitsulo kukhala zinthu zogwira ntchito ndi porosity yopangidwa. Njira yodabwitsayi imayamba ndi zida zopangira ndipo imatha ndi gawo lomwe limapereka mafuta osakanikirana nthawi yonse yomwe amagwira ntchito.

 

Powder Metallurgy: Kusintha Chitsulo kukhala Ufa ndi Kubwerera

Powder metallurgy amakhala ngati maziko a sintered kubala kupanga, kuyambira pakupanga zitsulo ufa. Opanga amagwiritsa ntchito atomized bronze ufa womwe uli ndi mkuwa wokhala ndi malata 9-11%. Ufawu umasakanizidwa ndi zowonjezera, kuphatikiza mafuta opangira phula omwe amathandizira pakuphatikizana. Kusakaniza kumadutsa pamakina amakina mu makina osindikizira pazovuta zoyambira 200 mpaka 1,500 MPa kutengera kuchuluka komwe kumafunikira.

Gawo "lobiriwira" limasunthira ku sintering pambuyo pophatikizana. Kutentha kumeneku kumatenthetsa chigawocho kufika pafupifupi 820 ° C mumlengalenga wolamulidwa wa nitrogen ndi haidrojeni (nthawi zambiri mu chiŵerengero cha 70:30). Kutentha kumakhala pansi pomwe chitsulo chimasungunuka koma chimafika pamtunda wokwanira kupangitsa kufalikira kwamphamvu. Tinthu tachitsulo timaphatikizana pamalo olumikizirana panthawi yofunikayi ndikupanga cholimba koma cholimba chomwe chimapangitsa kukhazikika kwake.

 

Microstructure of Sintered Materials: Porosity by Design

Sintered bronze bearings imakhala ndi porosity mwadala yomwe imakhala ndi cholinga, mosiyana ndi zitsulo zolimba. Ma bere awa amakhala ndi porosity pakati pa 15% ndi 25% ndi voliyumu. Izi zimasiyanitsa zida za sintered ndi zitsulo zotayidwa ndipo zimakhudza makina awo, matenthedwe, ndi magwiridwe antchito mochuluka.

The bearing's microstructure ilipores ogwirizanazomwe zimapanga network muzinthu zonse. Netiweki iyi imalola kuti mafuta aziyenda momasuka mkati mwazonyamula. Makhalidwe a ufa, kuthamanga kwa compaction, ndi mikhalidwe ya sintering zimatsimikizira kukula ndi kugawa kwa ma pores awa. Porosity imakhala "yotseguka" ikayendetsedwa bwino, zomwe zikutanthauza kuti pores amalumikizana m'malo mokhala ngati ma voids okha.

The porosity imachepetsa mphamvu zamakina poyerekeza ndi zitsulo zolimba koma zimapangitsa kuti ma berewa akhale ofunika popangitsa kudzipaka mafuta.^[2]. Mainjiniya amatha kusintha kuchuluka kwa porosity kutengera zomwe pulogalamuyo ikufuna, ndikupeza malire oyenera pakati pa mphamvu ndi mafuta ofunikira.

 

Njira Yopangira Mafuta: Kupanga Kudzipaka Wokha

Chovala chamkuwa cha porous chimadutsa m'miyendo yamafuta pambuyo pakuwotcha. Njira yofunikayi imasandulika kukhala gawo lodzipangira lokha. Kunyamula kumapita ku zipinda zotsekera momwe mpweya umachoka pamabowo asanamizidwe mumafuta apadera. Mafuta amadzaza pafupifupi 90% ya voliyumu ya pore yomwe ilipo kudzera mu capillary action.

Chovalacho chimagwira ntchito pogwiritsa ntchito njira yapadera yoperekera mafuta panthawi yogwira ntchito. Kutentha kochokera ku shaft kuzungulira pamalo otsetsereka kumapangitsa kuti mafuta atuluke kuchokera kumabowo kupita kumalo opangira shaft. Izi zimapanga filimu yopyapyala yopaka mafuta pakati pa magawo osuntha. Mafuta amabwerera ku pores kudzera mu capillary action pamene kubereka kumazizira panthawi yopanda ntchito, kusunga kayendedwe ka mafuta kosalekeza.^[2].

Kuzungulira kwamafuta kumapanga zomwe mainjiniya amachitcha "kupopa kanthu". Magawo odzaza amatulutsa mafuta panthawi yogwira ntchito pomwe malo osatulutsidwa amawatenganso. Izi zimapanga dongosolo losatha lopaka mafuta lomwe limagwira ntchito popanda kukonza. Ma bere odzipaka okha awa amatha kuyenda modalirika kwa maola 3,000-5,000 osafunikira mafuta ochulukirapo.

 

Zinthu Zakuthupi Zomwe Zimawonjezera Kugwira Ntchito

Sintered bearings amapeza ntchito yabwino kwambiri kuchokera kuzinthu zapadera zomwe zimachokera kuPowder metallurgy kupanga ndondomeko. Zinthu izi zimapereka ma sintered maubwino akulu kuposa zida zanthawi zonse kapena zomangika pamakina ambiri.

 

Kugawa kwa Mphamvu Zofananirako motsutsana ndi Zida Zoponya

Njira yopangira zitsulo za ufa imapanga phindu labwinoko kuposa njira zachikhalidwe zoponyera. Ziwalo zotayira nthawi zambiri zimakhala ndi zovuta chifukwa ma alloy osungunuka samazizira bwino. Izi zimapangitsa kusiyana kwa mphamvu, kachulukidwe, ndi kutentha kwazinthu zonse. Chomalizacho chitha kuipitsidwanso chitsulo chosungunuka chikakumana ndi zinthu zogulira panthawi yoponya.

Zigawo za sintered ndizosiyana. Amakhala ndi nyimbo zofananira pagawo lililonse lopanga. Zitsulo ufa particles kufalikira wogawana pamaso compaction ndi kukhala m'malo pa sintering. Izi zimapanga microstructure yosasinthika yomwe imakhala yamphamvu, yolimba, komanso yosamva kuvala mbali yonse.

Njira yopangira sintering imapereka kuwongolera kwapang'onopang'ono kwa zinthuzo kuposa kupanga kapena kuponyera. Kafukufuku wasonyeza kuti zokonzedwa bwino sintered zigawo zikuluzikulu akhoza kukhala 2-10 mphamvu kuposa zitsulo zotayidwa. Mphamvu imatha kukhala yotsika chifukwa cha porosity, koma imafalikira mozungulira gawo lonselo. Izi zimapangitsa kuti magwiridwe antchito omwe ali ndi katundu adziwike kwambiri.

 

Dimensional Kukhazikika Pansi pa Kusinthasintha kwa Kutentha

Sintered bearings imawala kwambiri ikafika posunga mawonekedwe awo pa kutentha kosiyana. Zigawozi zimasunga kulolerana kolimba komanso kupotoza kochepa chifukwa cha njira yawo yapadera yopanga.

Zinthu ziwiri zikuluzikulu zimapangitsa kukhazikika uku. Ma pores amapereka mpata wowonjezera pang'ono kutentha popanda kusintha miyeso yonse. Unifomu ya microstructure imakulanso ndikugwirizanitsa mofanana kuposa zipangizo zoponyedwa, zomwe zimalepheretsa kumenyana ndi kupsinjika maganizo.

Kukhazikika kumeneku kumathandiza kwambiri pamene kutentha kumasintha pakagwiritsidwa ntchito. Zitsanzo za aluminiyamu oxide zimachepa ndi 17.6% panthawi ya sintering pa 1600 ° C koma zimakhalabe ndi 98.3% yachibale ndi kusasinthasintha kwakukulu. Zida zachitsulo zimakhala zolondola ngakhale zitatenthedwa pamwamba pa 2500 ° F (1370 ° C) .

Kulondola kwabwinoko kumachokera pazowonjezera zoyendetsedwa. Silicon nitride yowonjezeredwa ku zitsanzo zosinthidwa za boron imathandizira kupewa kupotoza kwambiri panthawi ya sintering.

 

Valani Makhalidwe Otsutsana ndi Ma Common Alloys

Mutha kupeza ma sintered bearings mumitundu yosiyanasiyana ya aloyi, iliyonse ili ndi mawonekedwe ake okana kuvala:

Ma Alloys Opangidwa ndi Bronze: Wokhazikikasintered bronze(90% yamkuwa, 10% tin) imatsutsa kuvala bwino ndipo imakhala nthawi yayitali, ndikupangitsa kuti ikhale yabwino kwambiri pakugwiritsa ntchito. Kuonjezera ma graphite kumagulu opangidwa ndi mkuwa kumawathandiza kuti azigwira ntchito bwino popanda kukangana pang'ono komanso kukhala okhazikika pakutentha kosiyanasiyana.

Bronze Wotsogolera: Ma aloyiwa ali ndi lead 14-16% ndipo pafupifupi 20% yocheperako kuposa 90-10 bronze. Amapanga kukangana kochepa ndipo amakana kukwiya bwino mafuta akatsika. Mayesero amatsimikizira kuti zipangizozi zimatha nthawi 7-10 kuposa zitsulo zogubuduzika muzinthu zina (Pv=6-12 MPa·m/sec).

Zosakaniza za Copper-Iron: Ma alloys awa amaletsa liwiro la liwiro lamphamvu yopondereza. Amagwira ntchito kwambiri pakugwedezeka ndi katundu wolemetsa. Kuonjezera 1.5% ya carbon yaulere kumapangitsa kuti zipangizozi zitenthedwe kuti zifike kuuma kwa Rockwell C65, kuzipangitsa kuti zisagwire ntchito.

Ma Aloyi Opangidwa ndi Iron: Izi zimawononga ndalama zochepa koma zimakhalabe zabwino, zomwe zimawapangitsa kukhala otchuka m'magalimoto. Amakhala ndi mafuta ochulukirapo chifukwa cha porosity yapamwamba ndipo amakana kuvala bwino, ngakhale ali ndi malire otsika a PV.

Kutentha kwa sintering kumatenga gawo lalikulu pakuvala katundu. Ultra High-Temperature Sintering (UHTS) pamwamba pa 2500°F (1370°C) imapanga timabowo tating'ono, tofalikira muzinthu zonse. Izi zimapangitsa kuti ziwalozo zikhale zolimba, zolimba, komanso zosamva kuvala kuposa njira zanthawi zonse za sintering.

 

Self-Lubricating Sintered Bearings: Momwe Amagwirira Ntchito

 

Zodzitchinjiriza zodzitchinjiriza zimagwira ntchito kudzera munjira yodabwitsa yotsekera yomwe imayenda popanda thandizo lakunja. Zigawozi zimasamalira zodzoladzola zawo pogwiritsa ntchito njira zapadera zomwe zimagwirizana ndi momwe zimagwirira ntchito.

 

The Capillary Action Mechanism

Mphamvu ya mayendedwe odzipangira okha sintered amachokera ku mawonekedwe awo olumikizana a porous, omwe ali ndi 10% mpaka 35% ya voliyumu yonse yonyamula. Ma pores awa amapanga maukonde ovutirapo muzinthu zonse ndipo amagwira ntchito ngati nkhokwe zamafuta. Kudzaza koyambirira kwa ma voidswa kumachitika kudzera mu vacuum impregnation, pomwe mpweya umachoka m'mabowo mafuta asanalowe. Makoma a porous ndiye amakoka ndikugwira mafuta kudzera mu mphamvu ya capillary - njira yachilengedwe yomweyi yomwe imapangitsa madzi kukwera motsutsana ndi mphamvu yokoka mumipata yothina.

Mbali ya capillary iyi imapanga zomwe mainjiniya amachitcha kuti "running-in" pamwamba pa gawo lotsetsereka. Mudzawona kugunda kocheperako ngakhale chimbalangondo chisanagunde malo ake okoma. Kapangidwe ka microstructure kamakhala ngati siponji yomwe imasunga ndi kutulutsa mafuta odzola ngati pakufunika pa moyo wake wonse.

 

Kutulutsa Mafuta Panthawi Yogwira Ntchito

Chonyamulacho chimatulutsa mafuta pamwamba pake kudzera m'njira zingapo zikayamba kuyenda. Kutentha kochokera ku kukangana pakati pa shaft ndi kunyamula kumapangitsa mafuta kufutukuka. Kukula kumeneku kumakankhira mafuta ena kunja kwa pores kupita kumalo otsetsereka.

Kuzungulira kwa shaft kumapanga "kupopera zochita" nthawi yomweyo. Izi zimapanga madera oponderezedwa olakwika mufilimu yopaka mafuta ndipo imakoka mafuta ochulukirapo kuchokera pathupi kupita pamwamba. Pamodzi, mphamvu yopopera ndi kukulitsa kwamafuta kumapanga filimu yoteteza mafuta pakati pa tsinde ndi kunyamula kuteteza kukhudzana kwachitsulo ndi chitsulo.

Chovalacho chimafunika kusuntha kozungulira kuti chigwire ntchito bwino. Muyenera kuthamanga kwambiri komanso kusinthasintha kosalekeza kuti musunge filimu yonse yopaka mafuta pamtunda.

 

Rebsorption Panthawi Yozizira

Kudzipaka mafuta kumapitirira pamene kasinthasintha kaleka ndipo kuberekako kumazizira. Mafuta ochulukirapo amabwerera kumalo otsekemera kudzera mu capillary action pamene kutentha kumatsika. Kubwezeretsanso uku kumayimitsa mafuta aliwonse kuti asamangidwe kapena kudontha.

Chonyamula chimakokera mmbuyo mafuta omwe adakakamizika kuchoka m'malo odzaza panthawi yogwira ntchito. Kusinthana kosalekeza kumeneku - mafuta otuluka panthawi yogwira ntchito ndikubwereranso panthawi yopuma - kumapangitsa kuti mafuta aziyenda kosatha. Njirayi imapangitsa kuti mafuta azitha kufalikira mofanana pamtunda wotsetsereka, kotero kuti ntchitoyo imakhalabe yolimba ngakhale kuti sliding layer ikutha.

 

Magwiridwe Antchito: Zinthu za PV ndi Malire Olemetsa

 

Mainjiniya amayang'ana ma metric omwe amagwirira ntchito kuti asankhe ma sintered bearings omwe amafanana ndi zosowa zosiyanasiyana zogwirira ntchito. Izi zaukadaulo zimathandizira kudziwa malire ogwirira ntchito otetezeka ndikupewa kulephera koyambirira.

 

Kumvetsetsa Zinthu za PV Pakusankha Kubereka

PV factor imagwira ntchito yofunika kwambiri pakusankha ma sintered bearings. Mumawerengetsera pochulukitsa katundu wonyamula (P) mu mapaundi pa mainchesi sikweya ya dera loyerekezeredwa ndi liwiro la pamwamba (V) mu mapazi pamphindi. Izi zimatipatsa chilolezo cha kutentha kwapang'onopang'ono pamtunda womwe umakhudza mwachindunji kutalika kwake. Miyendo yodziwika bwino ya porous nthawi zambiri imakhala ndi mtengo wapamwamba wa PV wa 50,000. Opanga amalimbikitsa kuti azigwira ntchito mosalekeza pa 20,000 kuti awonjezere moyo wautumiki popanda mafuta owonjezera. Ma thrust bearings amafunikira kugwiridwa mosamala kwambiri ndi ma PV opitilira 10,000.

Kutalika kwa moyo wa chimbalangondo kumagwira ntchito mosiyana ndi mtengo wake wa PV - PV yapamwamba imatanthauza moyo wamfupi wautumiki. Ichi ndichifukwa chake mainjiniya nthawi zambiri amasankha ma PV otetezeka kwambiri pakapangidwe kuti zigawo zizikhala nthawi yayitali.

 

Static vs. Dynamic Load Capacity

Kuchulukira kosasunthika kumachitika pamene malo onyamula sakuyenda molumikizana. Mphamvu zakuthupi zimakhala zomwe zimalepheretsa pamilandu iyi. Ma static katundu malire amawonetsa mphamvu yomwe imasintha kukula kwa chimbalangondo ndi theka la kulekerera kololedwa.

Mphamvu yamphamvu imaphatikizapo kusuntha komwe kumachepetsa kunyamula. Ma sintered bearings nthawi zambiri amakhala ndi ma ratings osunthika pa gawo limodzi mwa magawo atatu a ma static katundu wawo. Kuchepetsa kwakukulu uku kukuwonetsa momwe kusuntha kosalekeza kumakhudzira malo okhala.

 

Kuthamanga Kwambiri kwa Zida Zosiyanasiyana za Sintered

Mtundu uliwonse wa sintered uli ndi malire ake othamanga. Zida zokhala ndi mkuwa zimakulolani kuthamanga kwambiri. Zolemba zopangidwa ndi chitsulo zimasinthanitsa liwiro kuti zikhale zolimba kwambiri. Ma fani a sintered okhazikika nthawi zambiri amathamanga pamtunda mpaka 1000 mapazi pamphindi.

 

Zotsatira za Kutentha pa Malire Ogwira Ntchito

Kutentha kumasintha kwambiri momwe ma sintered bearings amachitira. Mafuta ambiri opaka mafuta opangidwa ndi mchere amagwira ntchito bwino pakati pa 0-80°C. Kuchita kumatsika mofulumira kuposa 80 ° C, kugwera pafupifupi 60% yazinthu zabwinobwino.

Kutentha kumasinthanso momwe mafuta amayendera mkati mwa porous. Kutentha kotentha kumapangitsa kuti mafuta achuluke komanso aziyenda mosavuta kuchokera ku pores kupita kumalo onyamula. Kuzizira kumapangitsa kuti mafuta achuluke, zomwe zingachepetse kuyamwa koyenera mukayamba.

 

Kuyerekeza Sintered Bearings vs Ball Bearings

 

Mainjiniya amayenera kumvetsetsa kusiyana koyambira pakati pa sintered ndi mpira kuti akwaniritse magwiridwe antchito apamwamba. Mitundu yonyamula iyi imabwera ndi zabwino zake zomwe zimawapangitsa kukhala abwino kwa malo omwe amagwirira ntchito.

 

Kufananiza kwa Friction Coefficient

Ma fani a mpira ndi ma sintered amawonetsa mikangano yosiyana. Ma coefficients okangana a mayendedwe a mpira ndi otsika, kuyambira 0.0008 mpaka 0.0035 kutengera mtundu. Ma sintered bearings ali ndi mikangano yayikulu koma amakwaniritsa izi kudzera mwawomafuta-impregnated kapangidwezomwe zimawapangitsa kuti azipaka mafuta. Kukangana kokwanira mu mayendedwe a sintered kumakwera ngati mafuta akuchepa, zomwe zimawapangitsa kukhala osasankha bwino pamakina othamanga kwambiri popanda mafuta oyenera.

Mipira ndi kubetcha kwanu kwabwino kwambiri kuti muchepetse kutaya mphamvu chifukwa amagudubuzika m'malo moyenda ngati ma sintered bearings. Koma ma sintered bearings atha kukhala chisankho chabwinoko pakuyimitsa-ndi-kupita. Kudzitchinjiriza kwawoko kumalepheretsa zovuta za ndodo zomwe mumaziwona nthawi zambiri pama bere a mpira omwe sali opaka bwino.

 

Makhalidwe a Phokoso ndi Kugwedezeka

Sintered bearings imayenda mwakachetechete kuposa mayendedwe a mpira, makamaka pa liwiro lalikulu. Mipira imapanga phokoso chifukwa zinthu zomwe zimagubuduza zimalumikizana. Phokoso limakonda kuchulukirachulukira pamene mayendedwe a mpira amafika kumapeto kwa moyo wawo.

Zonyamula mpira zimatumiza kugwedezeka kochulukirapo kudzera pamakina amakina. Kafukufuku akuwonetsa kuti kugwedezeka kwambiri kumatha kuchepetsa moyo waufupi ndikupangitsa kuti ukhale waphokoso. Kuyenda kotsetsereka mu ma sintered bearings kumawathandiza kuti azitha kugwedezeka bwino. Izi zimawapangitsa kukhala chisankho chabwino pamapulogalamu omwe phokoso liyenera kuchepetsedwa.

 

Zofunikira Zosamalira: Zokonzedwa motsutsana ndi Kudzisamalira

Zofunikira zosamalira ma fani awa ndizosiyana kwambiri. Zonyamula mpira zimafunikira mafuta odzola pafupipafupi kuti azithamanga bwino ndikupewa kulephera msanga. Ma sintered bearings amasunga mafuta m'mabowo awo, omwe amapanga makina odzipaka okha omwe amafunikira chisamaliro chochepa.

Mufunika amisiri aluso kuti ayang'ane mayendedwe a mpira panthawi yantchito. Sintered bearings imagwirabe ntchito ngakhale ikuyamba kulephera. Kaŵirikaŵiri amapanga maphokoso m’malo mougwira kotheratu—mosiyana ndi maberelo a mpira amene angatsekedwe popanda chenjezo.

 

Utali wa Moyo Pansi pa Zochita Zosiyanasiyana

Mapiritsi a mpira amakhala nthawi yayitali m'malo othamanga kwambiri komanso olemetsa kwambiri. Malo ogwirira ntchito amathandizira kwambiri momwe mtundu uliwonse umagwirira ntchito. Sintered bearings imagwira bwino ntchito mosasunthika komanso mwachangu. Ma bere a mpira amathandizira kuyimitsidwa koyambira ndikusintha magwiridwe antchito bwino.

Kutentha kumakhudza kutalika kwa mitundu yonse iwiri yonyamula. Mipira imagwira ntchito bwino pamitundu yosiyanasiyana ya kutentha, yokwera komanso yotsika. Sintered bearings imagwira bwino ntchito mpaka pafupifupi 85°C. Pamwamba pa izo, amataya mphamvu zawo zopaka mafuta mofulumira.

 

Mapeto

Sintered bearings ikuyimira kupambana mu engineering yomwe imaphatikiza zitsulo za ufa ndi mphamvu zodzipaka mafuta. Mapangidwe awo a porous amapanga 10% mpaka 35% ya voliyumu yonse ndikupanga maukonde olumikizidwa omwe amaonetsetsa kuti mafuta azikhala opitilira.

Miyendo yatsopanoyi imakhalabe yokhazikika pa kutentha kosiyana ndikukhalabe ndi mphamvu mofanana mu kapangidwe kake. Ngakhale ma coefficients awo amakangana amaposa a mayendedwe a mpira, kudzipaka kwawo mafuta kumawapangitsa kukhala abwino kwa mapulogalamu omwe amafunikira kusamalidwa pang'ono komanso kuchita bwino.

Njira yopangira imadalira kulondola kwazitsulo ndi kutentha kwapadera kwa sintering pakati pa 800 ° C ndi 850 ° C. Izi zimapanga mayendedwe omwe amagwira ntchito modalirika pa zinthu za PV mpaka 50,000. Zolemba zamkuwa zokhazikika zokhala ndi 90% zamkuwa ndi malata 10% zimapereka chitetezo chabwino kwambiri pakuvala ndi dzimbiri. Zinthu izi zimawapangitsa kukhala ofunikira pamapangidwe apamwamba kwambiri.

Akatswiri amapeza kuti ma sintered bearings ndi ofunikira. Amagwira ntchito mwakachetechete, safuna kusamalidwa pang'ono, ndipo amagwira ntchito modalirika pothamanga komanso ponyamula katundu. Kuphatikizidwa ndi kudzipaka mafuta, izi zimawapangitsa kukhala chisankho chabwino kwambiri ngati ntchito yosasinthika, yopanda kukonza imakhala yofunika kwambiri kuposa liwiro lalikulu kapena kuchuluka kwa katundu.