Causes and solutions for Overheating of the drive axle reducer of Hydraulic excavators

1. Overheating phenomenon of the drive axle reducer: After the excavator has traveled a certain distance, the moving parts inside the drive axle undergo relative sliding friction, thus generating a certain temperature. It should not feel hot when touched by hand; otherwise, it is considered too hot.

2. Cause analysis

The main transmission components in the drive housing mainly include the main reducer, differential and wheel-side reducer, etc. The main reducer and the differential are connected together and centrally distributed in the middle of the drive axle. When this component is in operation, there is a sliding friction phenomenon.

Under normal circumstances, the surfaces of the relatively moving mating parts in the drive axle should have a layer of lubricating oil film as a medium to prevent direct contact and friction between the two parts. This not only delays the wear process of the machine parts, but also reduces the heat generated by friction. Through the flow of lubricating oil, the heat generated by the friction of the machine parts can also be carried away and dissipated, lowering the temperature of the main transmission part in the drive axle to maintain a normal temperature. Otherwise, the two mating parts inside the drive axle will experience semi-dry or dry friction when moving relatively due to the lack of lubricating oil, increasing the coefficient of friction and the corresponding frictional force, as well as raising the temperature. Due to the lack of lubricating oil, heat dissipation is poor, and the temperature of the machine parts cannot be dissipated and accumulates. The higher the speed and the longer the time of the machine parts' movement, the higher the temperature. It can be seen from this that the overheating of the main transmission part of the drive axle is caused by the direct friction between the working surfaces of the two relatively moving parts. The reason why direct friction can occur is that there is no lubricating oil or the lubricating oil is too little. Secondly, although there is sufficient lubricating oil, due to the too small fit clearance, when the gears mesh, the teeth are squeezed too tightly, preventing the formation of an oil film on the tooth surface and causing direct friction. Thirdly, when overloaded, the mating parts press against each other too much, breaking the oil film on the surface of the parts and causing direct friction, which leads to overheating. Fourth, due to the deterioration of the lubricating oil quality, it is difficult to form an oil film on the surface of the parts, and the two components will directly rub against each other and overheat.

3. Diagnosis and Exclusion

(1) If the drive axle overheats during use after maintenance, it is highly likely that the assembly is too tight. It should be inspected and adjusted.

(2) If overheating occurs due to prolonged uphill driving, it is mostly because of excessive driving under heavy load. One should stop and rest.

(3) If the inspection shows that overheating is caused by poor lubrication, the symptoms should be excluded accordingly. For instance, when lubricating oil is lacking, it should be replenished; when it deteriorates, it should be replaced.