Heavy truck gear refers to all kinds of gears in the gearbox of heavy truck. The automobile gearbox is located between the engine and the axle. The automobile relies on the gears in the automobile gearbox to transmit power and change the speed ratio, so that the automobile can move and move forward at different speeds. Due to the heavy load, usually from 8 tons to dozens of tons, the corresponding stress of the gear in the gearbox is large. Moreover, due to the different road conditions in China, the gearbox gear of heavy vehicles must be impacted frequently in order to adapt to various complex and changeable road conditions. Its strength, wear resistance, fatigue strength, impact toughness and other mechanical performance indexes are required to be higher than those of ordinary automobile gears.
Therefore, heavy truck gears are usually made of alloy carburized steel, and the heat treatment is also mainly carburized and quenched. The fatigue damage of gear is the same as that of heavy-duty automobile, which is the main form of gear failure under normal production conditions. The four main failure modes of gears are:
(1) Bending fatigue fracture of gear root;
(2) The tooth surface is seriously worn and the tooth thickness becomes smaller;
(3) Tooth surface peeling;
(4) Tooth impact, tooth breakage, etc.
Fatigue fracture accounts for more than one third of the total number of failed gears, ranking first; The second is surface damage. It can be seen that broken teeth are the main form of gear failure. The gear failure of heavy-duty vehicles produced by Hangzhou gear group is also mainly broken teeth, tooth surface wear and spalling.