40 KB1506 KB35 KB199920252009Hlebanja, GorazdHlebanja, Jože12 straniletnik:55številka:7/8str. 472-483ISSN:0039-2480COBISSID:11043355URN:URN:NBN:SI:doc-53E2QYUPenAssociation of Mechanical Engineers and Technicians of Slovenia et al.Zveza strojnih inženirjev in tehnikov Slovenije et al.Strojniški vestnikdrsenjemazanjetrenjezobnikiUniform power transmission gears|A new type of lubricated gears is presented in this paper, referred to as Uniform Power Transmission Gears (UPTG), which have conformal shaped teeth flanks that enable a more uniform transmission of power and motion. The proposed teeth flanks comprise three arcs: an addendum arc, a dedendum arc, with both of these joined by a connecting arc. These UPT gears have been derived from Hawkinsć patented Zero Sliding Gears (YSG) 4. The name Uniform Power Transmission Gears derives from the fact that these gears operate during power transmission with an almost constant value of friction and a nearly constant value of power transmission. Thus, the power transmission of the UPT gears occurs simultaneously with the doublecontact teeth flanks of the driving and driven gears, which means the transmitted power is divided into two parts: the contact pressure in the contacts is lower, and the gear pair conjugates as helical gears. UPT gears can be produced on common gear cutting machines based on a rolling process where teeth shapes are formed by successive enveloping cuts of a cutter. However, the cutter teeth should be manufactured by the UPT rack profile. A comparison of the UPTGs with involute-type gears is presented. The radii of curvature are investigated in detail and the velocities in the teeth flank contacts were analyzed. Additionally, an investigation of oil-film thickness using the theory of Hamrock and Dowson is discussed. Owing to the decisive influence of heat caused by friction on gearsć scuffing resistance, and the heating of the teeth flanks based on Blokćs flash-temperature criterion, we have made a careful study and the results are presented. Because the power transmission with UPTGs occurs mostly by rolling, with only a minor amount by sliding, such gears are verz suitable for heavy-duty power transmission at relatively slow speed working conditionsV članku predstavljamo novo vrsto mazanih zobnikov, tako imenovane zobnike z enakomernim prenosom moči - EPM zobnike, ki se odlikujejo po konformni obliki bokov zob, ki omogoča bolj enakomeren prenos obremenitve in gibanja. Predlagani profil bokov zob je sestavljen iz treh lokov, in sicer iz temenskega in vznožnega loka, ki sta povezana z veznim lokom. Ti EPM zobniki so izpeljani iz Hawkinsovih patentiranih zobnikov brez drsenja (Zero Sliding Gears) 4. Poimenovanje "zobniki z enakomernim prenosom moči" temelji na dejstvu, da se pri teh zobnikih prenaša obremenitev od gonilnega na gnani enakomerno in sočasno prek dveh parov zob, katerih dotikališči Pa in Pd sta na drsnem krogu s središčem v kinematskem polu C. Med prenosom moči deluje v dotikališčih bokov zob od gonilnega zobnika na boke zob gnanega zobnika sila, pri tem se pa gonilni boki kotalijo po gnanih bokih zob vzporedno s kinematično osjo po celotni širini zob ter hkrati drsijo po drsnem krogu. Tako se moč pri EPM zobnikih prenaša po dveh kontaktih bokov zob od pogonskega na gnani zobnik bolj s kotaljenjem in manj s trenjem, kar pomeni, da se prenešena moč deli na dva dela. Zato je kontaktna obremenitev bokov zob manjša in vdržljivost zobnikov večja. EPM zobniki so poševni, lahko jih izdelamo z orodjem, ki ima obliko EPM zobnice z običajnimi stroji za zobčanje na kotalni način. V članku je diskutirana primerjava EPM zobnikov z evolventnimi. Opredeljeni so krivinski radiji in analizirane hitrostne razmerev kontaktih bokov zob. Raziskana je debelina oljnega sloja z uporabo teorije Hamrocka in Dowsona. Vpliv toplote zaradi trenja na segrevanje in zajedanje bokov zob je ocenjen na osnovi Blokovega kriterija bliskovne temperature, rezultati pa so v članku predstavljeni. Ker se prenos moči pri EPM zobnikih odvija pretežno s kotaljenjem, z le majhnim deleem drsenja, so taki zobniki primerni za prenos velikih moči pri težjih in velikih pogonih in z relativno majhnimi delovnimi hitrostmiTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaUniverza v Ljubljani, Fakulteta za strojništvo