Naučne osnove razvoja transmisije poljoprivrednih traktora

The develolopment of technical systems is founded on scientific bases defining the purpose of the system itself. When agricultural tractors are concerned scientific cognitions are based on experiences acquired through operation, in various phases of technical and scientific achievements. Within the period of almost a hundred years of tradition, developmental concept of transmissions of agricultural tractors has gradually been brought into accord with engine power, tractor mass, velocity of movement and other requests, with the purpose of finding permanent improvements of pulling and dynamic characteristics, and all that with the view to optimizing agricultural and technical conditions and increasing the degree of rationalization of production. In the first phases of development of tractor transmissions shafting from engine was effected through gradual gearbox and main gearing to driving wheels. In further decades of development of transmission systems, more and more attention was paid to the development of gearbox gearings particularly in the increase of gear shift. In that way, optimal solution, i.e. the ideal pulling hyperbola, was nearer and nearer. In this work a short review is given of the analysis of agricultural tractors transmission from the aspect of improvement of pulling and dynamic characteristics, i.e. improvement of potential pulling characteristic of tractors.Razvoj tehničkih sistema bazira se na naučnim osnovama koje definišu namenu samog sistema. Kada su u pitanju poljoprivredni traktori, naučna saznanja baziraju se na stečenim iskustvima koja su sticana kroz eksploataciju u različitim fazama tehničkih i naučnih dostignuća. Koncept razvoja transmisije poljoprivrednih traktora kroz skoro stogodišnju tradiciju vremenom se usklađivao sa snagom motora, masom traktora, brzinom kretanja i drugim zahtevima, u cilju iznalaženja permanentnih poboljšanja vučno-dinamičkih karakteristika, a sve u cilju optimiranja agrotehničkih uslova i povećanja stepena racionalizacije proizvodnje. U prvim fazama razvoja traktorskih transmisija prenos snage od motora prenosio se preko stepenastog menjača i glavnog prenosnika do pogonskih točkova.U daljim decenijama razvoja transmisionih sistema, sve veća pažnja se posvećivala razvoju menjačkih prenosnika, pre svega u povećanju broja stepena prenosa. Na taj način sve više se prilazilo optimalnom rešenju,odnosno približenju idealnoj hiperboli vuče. U ovom radu dat je kratak osvrt analize poljoprivrednih traktora, sa aspekta poboljšanja vučno dinamičkih karakteristika, odnosno poboljšanja potencijalne vučne karakteristike traktora