Abstract
From the 19th century when the first gasoline tractor was designed and built we have seen incredible development in this field. Year to year the tractors becomes stronger, heavier and faster. In one decade we have seen 10 to 20 percent tractor power increase in each product line. Since the 1980's when the tractors reached the 300kW range brand new applications appeared in and outside of the agriculture for this heavy duty equipment. In the recent years transportation and in this respect the top speed of the tractors have become more important than before. Higher speed means less time spent on transportation task, more time left for the cultivation jobs. There are some extreme examples in the 200-300HP tractor class for 65-70 kph top speed but it these are not equipped with wet brakes because the state of the art the wet brake is applicable up to 50-55kph only. In the 300HP+ class the 35-40kph top speed became soon a minimum standard and there are already some examples for 50kph. So the top speed trends are easily predictable also at the heaviest end of the tractor load and performance range. And considering that the GVW of heavy tractors is far higher than 10t we san see that the tractor brakes will face higher challenges as ever before.
As usual in the automotive industry a new product must have higher performance data, weigh less, keep the previous dimensions at least and of course cost less. All these within the shortest possible lead time...
To meet all these challenging goals in this specific field the conventional design method does not seem to be efficient enough any more and therefore we need to found new ways and tools for the engineering. RÁBA Axle and the Széchenyi István University in Győr are working together to invent a new simulation method for the heavy duty wet brake systems in order to extend the current application limits especially the allowable maximum speed.
RÁBA as the designer and supplier of the axle pair of the Claas Xerion multifunction tractor (as well as some other agricultural and construction equipment) has over 10 years experience in this special field. This tractor has an engine performance of 380HP and its top speed is 50kph with a GCW over 20t.