OPTIMIZATION OF GEARBOX EFFICIENCY

Premda mehanički zupčanički prijenosnici korišteni kao pretvornici brzine i okretnog momenta već posjeduju vrlo veliku učinkovitost, daljnje smanjenje gubitaka njihove snage osim u motornim vozilima zadatak je i u mnoštvu industrijskih primjena. Razmatrani su različiti postupci smanjenja gubitka snage u zupčaničkim prijenosnicima. Gubici nezavisni o opterećenju se mogu smanjiti, osobito pri niskim temperaturama i uvjetima djelomičnog opterećenja korištenjem ulja male viskoznosti s visokim indeksom viskoznosti i male dubine uranjanja dijelova u ulje. Međutim, to utječe na svojstva hlađenja dodirnih površina zupčanika i ležaja. Sustav ležaja se može optimirati uporabom učinkovitijih sustava od onih s obostranim uležištenjem uz veliko predopterećenje. Zupčanici s malim gubicima mogu značajno pridonijeti smanjenju gubitka snage ovisnom o opterećenju na dodirnim površinama zupčanika. Radi daljnjeg smanjenja gubitaka na dodirnim površinama zupčanika i pripadajućih ležaja, dostupna su ulja s karakteristikom niskog trenja. Ukratko, tehnički je izvedivo smanjenje gubitaka kod zupčaničkog prijenosnika za otprilike 50 %. Problem predstavlja smanjenje značajnog gubitka snage s neznatnim utjecajem na sposobnost nošenja opterećenja, veličinu i težinu komponenata i stvaranje buke. Stoga je potrebno predložiti odgovarajuća kompromisna rješenja.Although mechanical gearboxes used as torque and speed converters have already very high efficiency it is not only a task in automotive applications to further decrease gearbox power losses but also in many industrial applications. Different methods are discussed for power loss reduction in a gearbox. No load losses can be reduced, especially at low temperatures and part load conditions when using low viscosity oils with a high viscosity index and low oil immersion depth of the components. This in turn influences the cooling properties in the gear and bearing meshes. Bearing systems can be optimized when using more efficient systems than cross loading arrangements with high preload. Low loss gears can contribute substantially to load dependent power loss reduction in the gear mesh. Low friction oils are available for further reduction of gear and bearing mesh losses. All in all a reduction of the gearbox losses in average of 50 % is technically feasible. The challenge is substantial power loss reduction with only minor impact on load carrying capacity, component size and weight and noise generation. Adequate compromises have to be proposed

CFD Simulations of Splash Losses of a Gearbox

Efficiency is becoming a main concern in the design of power transmissions. It is therefore important, especially during the design phase, to have appropriate models to predict the power losses. For this reason, CFD (computational fluid dynamics) simulations were performed in order to understand the influence of geometrical and operating parameters on the losses in power transmissions. The results of the model were validated with experimental results

OPTIMIZATION OF GEARBOX EFFICIENCY

Premda mehanički zupčanički prijenosnici korišteni kao pretvornici brzine i okretnog momenta već posjeduju vrlo veliku učinkovitost, daljnje smanjenje gubitaka njihove snage osim u motornim vozilima zadatak je i u mnoštvu industrijskih primjena. Razmatrani su različiti postupci smanjenja gubitka snage u zupčaničkim prijenosnicima. Gubici nezavisni o opterećenju se mogu smanjiti, osobito pri niskim temperaturama i uvjetima djelomičnog opterećenja korištenjem ulja male viskoznosti s visokim indeksom viskoznosti i male dubine uranjanja dijelova u ulje. Međutim, to utječe na svojstva hlađenja dodirnih površina zupčanika i ležaja. Sustav ležaja se može optimirati uporabom učinkovitijih sustava od onih s obostranim uležištenjem uz veliko predopterećenje. Zupčanici s malim gubicima mogu značajno pridonijeti smanjenju gubitka snage ovisnom o opterećenju na dodirnim površinama zupčanika. Radi daljnjeg smanjenja gubitaka na dodirnim površinama zupčanika i pripadajućih ležaja, dostupna su ulja s karakteristikom niskog trenja. Ukratko, tehnički je izvedivo smanjenje gubitaka kod zupčaničkog prijenosnika za otprilike 50 %. Problem predstavlja smanjenje značajnog gubitka snage s neznatnim utjecajem na sposobnost nošenja opterećenja, veličinu i težinu komponenata i stvaranje buke. Stoga je potrebno predložiti odgovarajuća kompromisna rješenja.Although mechanical gearboxes used as torque and speed converters have already very high efficiency it is not only a task in automotive applications to further decrease gearbox power losses but also in many industrial applications. Different methods are discussed for power loss reduction in a gearbox. No load losses can be reduced, especially at low temperatures and part load conditions when using low viscosity oils with a high viscosity index and low oil immersion depth of the components. This in turn influences the cooling properties in the gear and bearing meshes. Bearing systems can be optimized when using more efficient systems than cross loading arrangements with high preload. Low loss gears can contribute substantially to load dependent power loss reduction in the gear mesh. Low friction oils are available for further reduction of gear and bearing mesh losses. All in all a reduction of the gearbox losses in average of 50 % is technically feasible. The challenge is substantial power loss reduction with only minor impact on load carrying capacity, component size and weight and noise generation. Adequate compromises have to be proposed