AGMA-90FTM2-1990.pdf
《AGMA-90FTM2-1990.pdf》由会员分享,可在线阅读,更多相关《AGMA-90FTM2-1990.pdf(10页珍藏版)》请在三一文库上搜索。
1、90 FTM 2 An IndustrialApproachfor Load Capacity Calculationof WormGears (Verifying and Design) by: Michel Octrue,CETIM AmericanGear ManufacturersAssociation TECHNICALPAPER Copyright American Gear Manufacturers Association Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, Use
2、r=Wing, Bernie Not for Resale, 04/18/2007 12:15:04 MDTNo reproduction or networking permitted without license from IHS -,-,- An IndustrialApproachfor LoadCapacityCalculationof Worm Gears(VerifyingandDesign) Michel Octrue,CETIM The Statementsand opinionscontainedhereinare thoseof the authorand should
3、not be construedas an officialactionor opinionof the AmericanGearManufacturersAssociation. ABSTRACT: Themethodproposedin this paperis basedon an analyticalratingmethodwhichhas beendeveloped some years ago by the author(see AGMApaper88 FTM6). Thecalculationis basedon thedeterminationof the maximumof
4、pressurebetweenthematingteeth which is madeby usinga specificcriteriafor wormgears.This methodcanbe usedto verify theload capabilityof a wormgear but also to design a new gear coveringseveraltypes of toothprofile. Calculationsare providedas examplesandcomparisonshavebeenmadewith resultsobtainedby th
5、e initialanalyticalmethod,and by standardizedmethods(AGMA,BS). At theendof the papera comparisonis madewith experimentalresults. Copyright 1990 AmericanGearManufacturersAssociation 1500 King Street,Suite201 Alexandria,Virginia,22314 October,1990 ISBN:1-55589-554-9 Copyright American Gear Manufacture
6、rs Association Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 04/18/2007 12:15:04 MDTNo reproduction or networking permitted without license from IHS -,-,- AN INDUSTRIALAPPROACHTO LOAD CAPACITYCALCULATIONOF WORMGEARS VERIFYINGAND DESIGN M
7、ichel OCTRUE Gear Department CETIMSenlis FRANCE 1 INTRODUCTIONWe have indicated in 2 that this type of calculationleads to expressing the admitted torque to the wormwheelCOn re.N) using a rather simple If the differentratingmethods usuallyused for designingworm gearsformula: (1,8h 10) considertheir
8、limited life becauseof TEETHBREA- ( ZN_ 2 c rfo KAGE and CONTACTPRESSURES,experienceshows that in most=_2._u,m Z-_r)Z_ eases, it isthe SURFACEDEGRADATIONSOF THE WORMWHEEL which limit the gearinglife. with: ThemaincauseforSURFACEDEGRADATIONis thefatiguer_a: operating pitch radius of the wormwheel(in
9、ram) phenomenonon the materiallayer submittedto CONTACTPRESSU- RES. This has broughtus to developa method of calculationallowingohm,: admissiblepressureof the material (in MPa) to evaluate the level and distributionof contact pressuresalong the flanksZ g life factor of the teeth.Z_: elasticityfactor
10、 (in MPa to powerI/2) As opposed to existing methods ofcalculations,the distributionofcontactZ R:pressuredistributionfactor of the worm gear pressuresis no longer supposedto be uniform.(in square nun) The developmentthat foUows presents the method basis used as well as“ZR is composedof the global st
11、iffness factor RDGp whichtakesinto a simplifiedmethod which can easily be applied industriallyeither foraccount the global stiffnessof the gear and the (K_. :_,) o factor which verifyingor design,combinesthe mean equivalentstiffness (RD _q,_)L.j and the equivalent curvature radius (/? _q)t. j calcul
12、atedat the maximumpressureamplitude 2 REMINDEROF ANALYTICMETHODcontact point(index i, j) for the relativeposition of the wormand the wormwheel(index p): For a worm gear, the cartographic calculationof contact pressuresisZ_ =RDGv.(K_ ,_e_) obtained from a detailed analysis of meshing of a cylindrical
13、 worm with“ the mating conjugate wormwheel.In fact for this type ofgearthe gearing(XR_Nq_) conditions evolve continuouslyand differ from one point to another in(K_,/,-_)p =R_q. the same contact line; thus the name of analytical method (2 to 4).t.j. p The analysis of the meshingis performedat 2 steps
14、:with: - STEP1: it aimed to determinefor a relative position of the:c_: directive cosine of the normal to plan of contact worm and the wormwheelthe instantaneousload distributionThe power dissipatedin the meshing underfriction form is calculated along the meshing teeth. This distribution depends on
15、the teethfrom the determinedload distributionand the slidingvelocitywhich geometry,the contact geometryand the materials making upallow to calculate the friction coefficient in all contact point: from which the teeth.It is thus possibleto calculatea pressurelevel forwe deduce instantaneous efficeney
16、rl. The torque transmitted by the gear each contact point,is then expressedby: - STEP 2: by varyingthe relative position of the worm andC_=rI.C the wormwheelit isthen possible to study the contact pressure fields on the wholecontact zone of the gear.In this type of calculationthe difficult point is
17、the determinationof the The principleon whichis based the analytical ratingmethod rests onpressuredistributionfactor of the gear Z Rfor this requiresimpoffant determiningthe contact point for which the contact pressurefield attainscalculationmeans. To obtain a calculationmethod much easierto use, it
18、s maximum.The maximumload capacity admissibleby the gear isa simulated analytic method has been undertakento establish a variation thuslimitedby thepressureallowedbythe mostweakermaterialrole fortheZRfaetorinfunetionofthebasiegeometricalparameteraof (generallythat of the wormwheel)for the numberof r
19、equest cycles,the wormgear. 1 Copyright American Gear Manufacturers Association Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 04/18/2007 12:15:04 MDTNo reproduction or networking permitted without license from IHS -,-,- 3 ELABORATIONOF T
20、HE SIMPLIFIEDMETHOD Passing from the analytic method to the simplified method is performedI in 2 phases: I Lb2maxi.l - PHASE1: We haveto determine the basicgeometrical_ parametersaffectingZ_.To do so a data base of 375 gearsI was created,bZl_tandaxl - PHASE2: We have to improvethe variationrule for
21、Z_ factor in functionof the only infiuent geometrical parameters. To this purpose a second data base of 1064 gears was created,f The fixed parameters for the 2 phases were asfo,lowS:rnxlAxial module1_“-_,- _1:,1 C_xThread thicknessdistributioneoef-0,45 ficient Cj_Worm clearancecoefficient0,15RG 1 h=
22、lAddendumand dedendumAccordingFIGURE1- Definitionof wormwheelface width and externaladden- to BS721dumcoefficient x zWormwheeladdendummodifica-0Z lNumberof threads in worm1-2-3 tion4-5-6 Cj2Wormwheelclearancecoefficient0,15q_Diameterfactor6 to 20 with a pitch of 1 PROFILEType of thread profileI PROF
23、ILEao_iNormal pressure angle20 (INVOLUTE) MATERIALZ 2Number of teeth in wormwheel25 to 90 with WORM0,4 % carbon STEELa pitch of 5 WHEELChilled cast phosphorBRONZEb zWormwheelface widthb z_s CHART 1Constantparameterschosen to generate the data basesCh_2Wormwheelexternaladdendum0,7 coefficient The var
24、iable_arameters were: CHART2bVariable parametersto generatethe data base of 1064 ZlNumber of threadsin worm1-2-3gears 4-5 -6 q jDiameterfactor6-8-103.1 INFLUENCEOF GEOMETRICALPARAMETERS 12-14-16 A previousstudy 4 has shown that the pressuredistributionfactor of a0,Normal pressureangle15-17,.5-20the
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- AGMA 90 FTM2 1990
链接地址:https://www.31doc.com/p-3730657.html