Dab tsi yog Qhov Load-Txoj Cai Ntawm Lub Taper-Tav Thrust Bearing?

ATaper-land Thrust Bearingyog ib hom hydrodynamic thrust bearing nrog tsau geometry. Nws tsis muaj qhov pivot, tsis muaj qhov hloov pauv tsis siv neeg thiab tsis muaj kev hloov kho tsis siv neeg. Lub bearing nqa axial load los ntawm kev siv ib tug wedge inlet cheeb tsam machined ncaj qha mus rau lub bearing nto.

Lub peev xwm ntawm cov kabmob muaj peev xwm los ntawm cov kab no. Thaum lub rotating nto txav lubricant mus rau hauv ib tug nqaim qhov sib txawv, cov ntaub ntawv siab nyob rau hauv cov roj zaj duab xis. Lub siab no txhawb nqa lub axial load thiab ua kom lub ntsej muag sib cais thaum lub sijhawm ua haujlwm.

Txij li thaum bearings nyob ntawm tag nrho nws cov machined geometry, qhov ntev ntawm cones yuav tsum tau ua tib zoo tswj. Cov kev hloov me me hauv lub kaum sab xis, zaj duab xis thickness lossis cov duab saum npoo tuaj yeem cuam tshuam rau lub zog tsim thiab kev ua haujlwm ntawm cov kabmob.

Yuav kom nkag siab txog yuav ua li cas conical thrust bearings ua haujlwm, nws yog ib qho tsim nyog yuav tau soj ntsuam cov hydrodynamics ntawm lub siab generated nyob rau hauv lub lubricating zaj duab xis, es tsis txhob tsuas saib bearings raws li cov khoom nrog aa teev load ntsuam xyuas.

Core Mechanism: Hydrodynamic Pressure los ntawm Converging Wedge

Txhua hydrodynamic kua zaj duab xis bearing, nrog rau cov phau ntawv journal bearings, tiltpad thrust bearing thiab tapered hauv av thrust bearing, muaj tib lub peev xwm bearing raws li lub cev los ntawm Osborne Reynolds nyob rau hauv 1886. Thaum cov kua nplaum yog dragged los ntawm ib tug nqaim qhov sib txawv los ntawm kev txav ntawm ob qhov chaw, siab nyob rau hauv cov kua membrane nce. Lub siab no, thaum kis mus rau thaj tsam ntawm cov kabmob, txhawb nqa lub nra uas tsis muaj hlau - mus rau - hlau sib cuag.

Hauv Taper-land Thrust Bearing, qhov sib txawv ntawm qhov nqaim no yog tsim los ntawm kev kho geometry es tsis txav los yog kho. Txhua gasket ntawm lub nplhaib bearing muaj ob qhov chaw tseem ceeb nyob rau hauv cov kev taw qhia ntawm kev sib hloov.

Taper cheeb tsam (inlet): Qhov saum npoo yog ntawm lub kaum me me rau txoj kev khiav. Qhov no tsim qhov sib txawv uas nqaim raws li cov roj yog rub sab hauv los ntawm kev sib hloov. Feem ntau ntawm hydrodynamic siab yog tsim nyob rau hauv cheeb tsam no.

Pav ca (qhov hluav taws xob): nto sib npaug mus rau qhov khiav. Qhov chaw no tuav lub siab tom qab nws tsim thiab cov roj tawm ntawm lub ncoo ntawm tus Tsov tus tw ntug rau hauv qhov dej ntws.

Qhov piv ntawm cov av tiaj tus ntev mus rau tag nrho cov ncoo ntev yog feem ntau 0.60-0.70. Yog tias cov av tiaj tus luv dhau, tsis muaj qhov chaw txaus los tiv thaiv qhov tshwm sim. Yog tias koj siv sijhawm ntev heev, thaj tsam taper yuav tsawg dhau thiab lub siab yuav tsis nce ntxiv.

Reynolds Equation Applied to Taper Geometry

Ib daim ntawv -dimensional form ntawm Reynolds equation rau ib qho incompressible, tas li-viscosity zaj duab xis nyob rau hauv khov kho yog:

d/dx (h³ dp/dx)=6 μ U dh/dx

Nyob rau hauv qhov sib npaug no, h yog lub zos zaj duab xis thickness, p yog siab, mu yog dynamic viscosity, U yog txheeb ze nto tshaj tawm, x yog coordinates ntawm kev taw qhia ntawm tsab ntawv tsa suab.

Rau linear conical inlets, h (x) txo qis ntawm tus nqi tas mus li los ntawm qhov tuab ntawm inlet membrane h1 mus rau qhov tsawg kawg nkaus daim nyias nyias h2 ntawm lub khob hliav qab - av junction. Lub siab gradient dp / dx nyob ntawm μU thiab dh / dx. Qhov no muaj qhov cuam tshuam ncaj qha hauv qab no:

• Kev kub ceev ua rau cov yeeb yaj kiab siab thiab ua kom muaj peev xwm thauj khoom thaum cov yeeb yaj kiab tuab yog tib yam.

• Cov viscosity siab dua ua rau cov nyhuv tib yam li qhov nrawm dua.

• Ib tug steeper taper tsis tas yuav txhim kho kev ua tau zoo. Yog tias lub kaum sab xis loj dhau lawm, lub siab ua kom ze ze rau qhov nkag thiab qhov kev faib tawm tag nrho yuav tsis sib xws. Qhov no txo ​​cov peev txheej tag nrho.

Qhov zoo tshaj plaws cone piv ntawm h1 / h2 ntawm qhov siab tshaj plaws bearing muaj peev xwm yog hais txog 2.2 nyob rau hauv laminar ntws thiab tas li - viscosity tej yam kev mob. Qhov no txhais tau hais tias qhov kev noj cov yeeb yaj kiab thickness yog li 2.2 npaug ntau dua li qhov tsawg kawg nkaus zaj duab xis. Tshwj xeeb, yog tias qhov tsawg kawg nkaus zaj duab xis thickness yog 15-25 μm, qhov siab nkag siab yog kwv yees li 33-55 microns. Qhov no yog ib qho kev ua haujlwm ruaj khov, tsis yog ib yam uas hloov pauv hauv kev ua haujlwm.

Geometry vs. Adaptive qaij: Yuav ua li cas Taper- av txawv ntawm Tilting -Pad

Lwm txoj hauv kev rau conical hauv av tsim yog tiltpad (Michell / Kingsbury) thrust bearing. Nyob rau hauv cov qauv no, txhua lub ncoo yog mounted rau ib tug pivot. Lub gasket tuaj yeem tilted thiab angled raws li kev ua haujlwm thiab kev khiav haujlwm.

Qhov no tus kheej - kho qhov txav tso cai rau lub gasket kom pom lub kaum sab xis zoo tshaj plaws thaum ua haujlwm. Nws pab bearings tsim cov roj yeeb yaj kiab ruaj khov thoob plaws ntau yam ntawm kev nrawm thiab thauj khoom.

Qhov sib txawv ntawm ob qho kev tsim qauv qhia txog qhov zoo thiab kev txwv ntawm conical hauv av bearings:

Taper taper yog hais txog qhov ua tau zoo tshaj plaws ntawm Taper-av Thrust Bearing ntawm qhov tsim ua haujlwm. Vim tias ceev qis dua li tsim, cov yeeb yaj kiab hydrodynamic thins thiab cov bearings yog lubricated ze rau ntawm ciam teb - sib tov - lubrication hloov tau piav qhia hauv qab no.

Load Capacity, Ceev, thiab Sommerfeld Number

Load peev ntawm taper - av thrust pad nplai nrog covbearing naj npawb(qee zaus hu ua Sommerfeld tooj rau thrust bearings), txhais tau tias:

S=μNP(Rc)2S=PμN​(cR​)2

qhov twgNyog rotational speed (rev/s),Pyog txhais tau tias bearing siab (load ÷ projected cheeb tsam),Ryog tus yam ntxwv radius, thiabcyog cov ntaub ntawv clearance ntsig txogh₂. Rau ib tug muab geometry, load peev xwm yog kwv yees proportional rauμNU- lub ntsiab lus bearing muaj peev xwm ntsuas linearly nrog ceev.

Cov peev txheej muaj peev xwm ua tau zoo rau taper- av thrust pads hauv kev pabcuam kev lag luam (Boyd thiab Rowe, 1982; Wilcock thiab Booser, 1957):

Yog tias koj tshaj qhov txwv tab sis tsis nce viscosity lossis ceev los ntawm tib tus nqi, ces zaj duab xis yuav vau thiab koj tau txais ciam teb lubrication. Yog tias koj mus qis dua qhov tsawg kawg nkaus ceev, cov kabmob loj dhau rau cov khoom thauj. Qhov no tsim ib qho teeb meem sib txawv: cov roj tsis txav mus rau hauv thiab cheb thaj tsam taper sib npaug txaus, yog li qhov ntsuas kub tsis sib npaug ntawm qhov dav ntawm lub ncoo.

Groove Geometry thiab Thermal Management

Txhua taper- av pad yog sib cais los ntawm qhov tom ntej los ntawm ib tug circumferential groove. Qhov zawj muaj ob txoj haujlwm: nws tshem tawm cov roj kub los ntawm sab nraub qaum ntawm ib lub ncoo, thiab nws muab cov roj txias rau hauv pem hauv ntej taper ntawm lub ncoo tom ntej. Qhov kev sib pauv roj no yog txoj hauv kev tseem ceeb los tswj cov cua sov hauv taper - av tsim. Vim tias taper- av bearings tsis muaj kev taw qhia lubrication zoo li tilting-pad bearings, yog li lawv nyob ntawm qhov zawj turbulence kom sib tov roj kub thiab txias ua ntej nws mus rau hauv taper tom ntej.

Groove dav feem ntau yog 15-25% ntawm tag nrho cov ncoo suab. Cov grooves me me ua rau qhov sib txawv ntawm cov ntaub qhwv me me, yog li lawv siv qhov chaw zoo dua. Tab sis lawv kuj ua rau cov roj sib tov thiab ua rau nqa - kub dua. Nqa- kub dhau yog qhov kub ntawm cov roj mus rau hauv lub taper piv rau qhov ntsuas kub. Ettles (1969) tau pom tias qhov nqa tau- dhau qhov feem ntau tuaj yeem ua rau 40-70% ntawm cov yeeb yaj kiab kub nce hauv taper{12}} qauv tsim av thaum khiav siab tshaj 50 m / s khiav nrawm nrawm. Yog li qhov no zoo heev txo qis cov viscosity thiab tom qab ntawd txo qis lub peev xwm.

Nyob rau hauv siab peripheral speeds siab tshaj 60 m / s, viscous cua sov ua lub ntsiab tsim txwv tsis pub load. Roj mov kub yuav tsum nyob twj ywm ntawm 40-49℃nrog ISO VG 32-46 turbine roj. Qhov no yog ua kom lub siab tshaj plaws zaj duab xis kub hauv qab 95-100 degree. Qhov kub ntawd yog qhov taw tes uas thermal puas rau cov roj ntxiv pob nrawm nrawm.

Tsawg-Speed ​​thiab Pib-Stop Failure Mechanism

Qhov loj tshaj kev txwv ntawm conical av tsim yog txoj kev nws ua hauj lwm thaum pib, kaw thiab khiav ntawm tsawg speeds. Vim tias cov yeeb yaj kiab hydrodynamic siab nyob ntawm qhov ceev, qhov nruab nrab ntawm cov kabmob siab ntawm 2.0 MPa tuaj yeem tsuas yog 20% ​​0.3-0.5 MPa ntawm qhov ceev. Yog hais tias cov ntaub ntawv thov thrust load loj dua qhov qis membrane muaj peev xwm, qhov tsawg kawg nkaus zaj duab xis thickness yog tsawg tshaj li qhov roughness ntawm nto - feem ntau 0.5 mus rau 1.5 μm Ra rau hauv av bearing log - thiab asperity hu tshwm sim.

Rov qab pib thiab nres lub voj voog nyob rau hauv load ua rau ruaj khov thiab tsim kua muag ntawm lub tiaj tiaj, uas yog irreparable. Tsis zoo li tiltpad bearings, qhov chaw me me ntawm kev hnav ntawm qhov pivot tseem tuaj yeem ua rau lub ncoo tsis ntev los no, hnav ntawm thaj chaw tiaj tus ntawm lub conical hauv pem teb ncaj qha txo qhov chaw siab thiab ua kom muaj kev puas tsuaj ntau dua. Lub ASTM D-4998 plaub- pob coj mus kuaj feem ntau yog siv los tshuaj xyuas qhov ua tau zoo ntawm cov roj tiv thaiv- hnav cov khoom ntxiv hauv qab sib xyaw lubrication pib thiab nres. Qhov no yog vim hais tias cov roj ntau-siab additives muab cov kev txhawb nqa nkaus xwb thaum cov yeeb yaj kiab hydrodynamic tseem tsis tau tsim.

Rau cov cav tov uas feem ntau pib nyob rau hauv load-xws li lub cev muaj zog tsav twj tso kua mis uas voj voog ntau zaus ib tug ua haujlwm - qhov kev xaiv ntawm qaij pads yuav tsum tau txiav txim siab. Xwb, lub conical hauv av specification yuav tsum muaj xws li ib tug hydrostatic nqa system los thawb cov roj externally rau hauv zaj duab xis ntawm tsawg speeds.

Cov ntsiab lus ntawm kev siv tswv yim

Lub tswv yim ntawm cov bearings ntawm terraced thrust bearings yog feem ntau embodied nyob rau hauv peb yam nram qab no:

1.Convergent wedge shape-Txiav rau hauv taper inlet ntawm h1/h2 arc 2.2, yog li nws tsim hydrodynamic siab los ntawm Reynolds mechanism.

2.Cov av tiaj tus -60-70 feem pua ​​​​ntawm qhov ntev ntawm lub gasket-muab qhov chaw siab rau cov kabmob axial.

3. Cov dej ntws tawm -Qhov no muab cov roj txias rau lub khob tom ntej thiab nres cov viscosity ntawm cov thermal breakdown membrane.

Tsis muaj ib qho ntawm peb qhov tsis tuaj yeem hloov pauv ib se, vim tias txhua qhov kev hloov pauv cuam tshuam rau tag nrho peb qhov kev ua tau zoo: lub peev xwm thauj khoom, qhov kub thiab txias ntawm zaj duab xis thiab cov yeeb yaj kiab tsawg kawg nkaus. Yog li ntawd, engineers yuav tsum pib nrog qhov nruab nrab bearing siab ntawm ib txwm ceev thaum xaiv ib tug conical av ntaus ntawv rau ib tug tshwj xeeb tshuab. Tom qab ntawd lawv yuav tsum xyuas kom meej tias tus lej Sommerfeld muab cov kabmob hauv lub xeev daim nyias nyias. Tom qab ntawd lawv yuav tsum paub meej tias qhov pib nres uas pib - nres zaus thiab lubrication system muab qhov kub thiab txias ua haujlwm tsis pub dhau qhov txwv geometric. Qhov no yog vim hais tias, tsis zoo li pivot pad tsim, conical hauv av bearings tsis tuaj yeem kho lawv tus kheej tsim kev ua haujlwm.

Cov ntaub ntawv

• Reynolds, O. (1886). Ntawm txoj kev xav ntawm lubrication thiab nws daim ntawv thov rau Mr. Beauchamp Tower qhov kev sim, suav nrog kev sim txiav txim siab ntawm viscosity ntawm txiv roj roj.Philosophical Transactions ntawm Royal Society of London, 177, 157–234.
• Boyd, J., & Rowe, WB (1982).Tribology: Cov Ntsiab Cai thiab Tsim Cov Ntawv Thov. Macmillan Xovxwm.
• Wilcock, DF, & Booser, ER (1957).Bearing Design thiab Application. McGraw-Hill.
• Ettles, CMM (1969). Cov roj kub nqa- dhau ntawm cov kabmob thrust.Kev Ua Haujlwm ntawm Lub Tsev Haujlwm ntawm Mechanical Engineers, 184(12), 75–81.
• Hamrock, BJ, Schmid, SR, & Jacobson, BO (2004).Lub hauv paus ntawm Fluid Film Lubrication(2nd ed.). Marcel Dekker.
• Frêne, J., Nicolas, D., Degueurce, B., Berthe, D., & Godet, M. (1997).Hydrodynamic Lubrication: Bearings thiab Thrust Bearings. Elsevier.
• Khonsari, MM, & Booser, ER (2008).Applied Tribology: Bearing Tsim thiab Lubrication(2nd ed.). Wiley.
• Szeri, AZ (2011).Fluid Film Lubrication(2nd ed.). Cambridge University Press.
• ASTM D4998-22.Standard Test Method rau Kev Ntsuam Xyuas Hnav Cov yam ntxwv ntawm Tractor Hydraulic Fluids. ASTM International.
• ISO 12168-1: 2001Plain bearings - Static load- nqa lub peev xwm ntawm hydrodynamic thrust dab tshos bearings yam tsis muaj tilting pads. ISO.
• Stachowiak, GW, & Batchelor, AW (2014).Engineering Tribology(4th ed.). Butterworth -Heinemann.