Three stage reduction gear with paired first and third stage gears

Osnovni zadatak ovog završnog rada je bio izvođenje proračuna i konstruiranje trostupanjskoga reduktora sa dvostruko uparenim zupčanicima prvog i trećeg stupnja. Proračun je započet proračunom zupčanika prema stupnjevima prijenosa, kod kontrolnog proračuna 3. stupnja, zupčanici nisu zadovoljavali postavljene uvijete te je bilo potrebno ponovo proračunati zupčanike 3. stupnja, te se pritom uzeo veći razmak osi i veće dimenzije zupčanika kako bi izbjegli daljnje greške. Nakon proračuna zupčanika proračunata su vratila, te kod njih nije dolazilo do većih problema, a potom su odabrani odgovarajući ležajevi za krajeve vratila koji su proračunati i usvojeni iz SKF kalkulatora. Po završetku odabira ležajeva, odabrana su pera za vratila kod kojih je dolazilo do problema da nisu zadovoljavala zadani uvjet pa je bilo potrebno usvojiti 2 standardna pera iz tablice [2] te njih postaviti razmaknute za 120° po osi vratila. Na krajevima vratila te na mjestima gdje je bilo potrebno osigurati zupčanike, postavljeni su uskočnici koje smo odabrali prema DIN standardu iz tablice [2]. Pri odabiru kućišta prvo je bilo potrebno pravilno rasporediti vratila, te zupčanike kako bi ostvarili najmanje moguće dimenzije reduktora, a samim time i smanjili troškove izrade. Nakon razrade kućišta proračunat je te konstruiran sustav hlađenja i podmazivanja zupčanika nakon čega je još samo bilo potrebno odabrati ostale dijelove reduktora, kao što su: uljokaz, vijci, poklopci vratila... Unatoč svim problemima, reduktor je uspješno proračunat i konstruiran tako da zadovoljava sve postavljene uvjete, te da je jednostavan i jeftin za izradu, a pritom su otklonjene sve moguće greške.The basic task of this final work was the calculation and the design of a three-stage reduction gear with paired first and third stage gears. The calculation was initiated with the gear ratios, at the 3rd stage control calculation, the gears did not meet the set conditions and it was necessary to recalculate the 3rd gear stage, thereby increasing the center distance and increasing the gear dimensions to avoid further flaws. After the gears were calculated, there were no major problems with them, and then the corresponding bearing shafts were calculated and the required rolling bearings were selected from the SKF calculator. Upon finishing the selection of bearings, shaft keys were selected, however they did not meet the required conditions, so it was necessary to adopt two standard keys from table [1] and set them spaced by 120° to the shaft axis. At the ends of the shaft and in the places where it was necessary to secure the gears, snap rings were chosen according to the DIN standard. When the casing was being designed, it was necessary to properly align the shafts and gears to achieve the least possible gear unit dimensions and thus reduce the cost of manufacturing. After the housing was designed, the cooling and lubrication of the gearbox were calculated, after which it was only necessary to select the other parts of the gear unit, e. g. oil sump, screws, shaft covers... Despite all the problems, the gearbox has been successfully calculated and designed to meet all the required conditions and that is easy and economical to manufacture while eliminating all possible design errors