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0. [1400. 970. L,J s, [1200. 1170, LJ .Fig, 9 -I'red.iction s, [1500, 600. l..l 0. [1500,900, I.,I rig. to -Prediction 0.211 N.[l." 14001.N,IL •. 12001 8·10' 01 wear by DIN 3996 Cor ratiol 3131 in flJDCtiOD'Of ol!lllbe., of ,cycles. 0.03 ,..---------------, 0.02 0.01 1'10' 2'10' 3'10' N,ll. •• 1500] of wear by DIN 3996 for ratlo 5124- In flJDclion of number of cycles. fi~.U - Wonn geali' 1/40: n, '" 1600 FPm; C, = U74 Nrn after 2323 hours, Fig. 12- Wurm gear ~/40: II', ... 600 rpm; C, :: 1374 Nm aft!!r 4477 hOIlI'S. 34, GEAR TECHNOLOGY , ! teeth is produced becau e material is removed, but I l!he physical basi here i contact pressure. TIle intensity 0:1' this phenomenon is direclly linked to the radius curvature di tribution of the worm gear. If this distribution is regular, as in one-start worm gears, the equivalent wear phenomenon will propagate slowly, and the resulting level of wear will be low. When the pre ure di tribution is not regular, as in the case of 3- or 5-start wonn gears. the ,equivalent wear phenomenon grows quickly. and the resulting wear [eve] is high. This is ob erved in Figs. 5-7. In these cases, the heterogeneity of the worm wheel material, can produce a 11011,- homogeneity of tooth-to-tooth wear, !.hereby inducing pitch errors durmg working. These pitch error can create intemal dynamic effects caused by the bad load haring between teeth, increasing the propagation of the equivalent wear phenomenon and, sometimes, the production of chocks during meshing. A New Approach hi order to have abetter prediction of worm gear life, it is nece ary 'to have an approach based on the observed behavior of worm wheel flanks during working. Our observations, described above, have shown that pressure contact phenomena are the basis of this kind of prediction. This implies the need to have a good knowledge of how the worm wheel i. affected by contact pre sure fatigue. To answer to this first question, CETIM has developed experimental investigations to determine S-N curves for several bronzes on roller-di k machines (Ref. 6). In another way CETIM ha developed an analytical method to determine contact pressure distribution, taking into account geometry (radius of curvature),kinemalics (sliding velocity) and elasti.city (gear tooth tiffness). By coupling S-N curves with contactpre sure distribution calculations, i.t is possible to predict the zones of looth flanks on which scales will appear. Then the calculation of removed surfaces can be made, and a new contact pressure distribution can be established. Taking into account the cumulative damages with S-N curves, the Life of each point of flank surface can bepredicted as the quantity of removed material and the equivalent wear phenomena. This calculation has to be done iteratively: The contact pressure distribution is adjusted at each step, taking into account the leaving surface on worm wheel flanks. The urface strongly tressed i then removed. laking into account the contact
Fig. 13 - Wonn, gear 1/4.0:II', = 1600 rpm; e,,= 13'74Nm Ifig. 17 - Worm gearJlU: PI, '" 1.mo rpm; e, '" 7SO'Nm oner 686J hours, aller 40'32hours, fig. 14- Worm:gear 1140:", '" m600 rpm; C,= 1374 Nm ! !FIg. 1:8- Worm gear 3131: ", = 1400 rpm; e, = 750 Nm uftcr 7898 hours, I aner 5292 hnurs, lFig. IS - WOrn! gl!or JlJI: II, = 1400 rpm; C, = 750 Nm Fig. 19 - Worm gear 3131:n, '" 1400 rpm: e,'"750 Nm aner 735 heurs, afI.er 8OtJ3 hours. lFig.16 - Worm gear 3131: II, := 1400 rpm: ,e, :: 750 Nm ! fig. 20 - Worm ge r S/24: II, ., 11200rpm,; C, = 800 Nm LRu 330Z hours, II after U13 hears, FOR ALL LOADING CONDI11ONS. A PERIOD OF MESHING, CORRESPONDING TOTHEnMEIT TAKES SURFACES TO ADAPT. EXSISTS DURING WHICH NO WEAl APPEARS. THEN BACKlASH BEGINS AND EVOLVES CONnNUOUSLY. IIIAYIJUNIE 1991 35
Page 2 and 3: ..~.~.~=====~~ ~~ ~ ~~ -- . ~=~~ 1M
Page 5 and 6: FEATURES i The Journal ,ojaear Manu
Page 7 and 8: The most for YOUI money. PCoeasea H
Page 9 and 10: • PUB,IuI:SHER'S PAGE • BBTING
Page 11 and 12: ear If you make gears we'll make yo
Page 13 and 14: e inoid-bonded wheels may bea good
Page 15 and 16: CIRCLE1i14
Page 17 and 18: •••••••••••
Page 19 and 20: _------------TECHNICA1.FOCUS-------
Page 21 and 22: After awarding the contract. the pu
Page 23 and 24: AGMA and ISOI Accuracy Standards Ro
Page 25 and 26: Our family of gear machines shares
Page 27 and 28: ADIVERJISER INIDEX For .,. iIforwII
Page 29 and 30: 3500 Be - Man Invents the wheel and
Page 31 and 32: IGRS~2Double-Flank 'Gear Roner Syst
Page 33 and 34: Experim otal.Approach For the last
Page 35: as for the experimemal observations
Page 39: ____ I TECHNliC.AL ICAIlIE:NDIAR _
Page 42 and 43: Fig, 3,- 'Chips Irom dTl' cutting;
Page 44 and 45: ____ NEW TECHNOLOGY 1 _ I N!El:IlI\
Page 47 and 48: • .GiEARi~UNIDA!MENTALSI _ Hobs &
Page 49 and 50: _------------GiEARlfUNDA!MENTA!lS!-
Page 51 and 52: _------------IPRODUCfNEWS----------
Page 53 and 54: SUllVlrablBsiVie SC-y··s*ems tor
Page 55 and 56: HOW TO ESTAiUSH A PRESENCE ON THE G
Page 57 and 58: SERVICE HELP WANTED - --- GR \PIIU'
Page 59: KRPP Sales and Service Problem Solv

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