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In the construction of large excavators, the amount of earthwork is large and the walking is not frequent. When the excavators transfer the working place for a long distance, they usually use trailers for transportation. However, small excavators often need to move to the work place by themselves for a long distance because of the small amount of earthwork. Due to the frequent and long-distance walking of small excavators, the early wear of the roller axle is often caused.

1. Cause of damage

The roller of small crawler excavator is mainly composed of wheel body, wheel axle, copper sleeve, floating seal ring, O-ring and end cover. There are five reasons for the early wear of the roller axle: one is that the roller heats up during frequent and long-distance walking, diluting the lubricating oil and making the lubricating effect worse. The second is that the pressure on the friction surface of the floating seal ring is too high, when the lubricating oil is diluted, the friction surface of the floating seal ring is scratched, resulting in oil leakage of the floating seal ring. Third, high temperature accelerated the aging deformation and elasticity reduction of O-ring at floating seal ring, resulting in oil leakage of O-ring. Fourth, after the oil leakage of floating seal ring and O-ring, the wheel axle, copper sleeve and other parts are worn. Fifth, the lubricating oil cavity composed of the wheel body and the end cover is too small, and there are few lubricating oil hinges stored. When the lubricating oil deteriorates and leaks, the wheel axle and the copper sleeve cannot be fully lubricated.

2. Improvement measures

In order to solve the problem of oil leakage of the roller, it is necessary to solve the problems of high temperature heating and sealing at the two floating sealing rings. The improved roller is shown in the attached figure, and the specific improvement measures are as follows:

The first is to change the angle of the inner floating seal ring cavity of the end cover from 15 ° to 10 ° so as to increase the contact surface between the end cover and the O-ring and prevent the relative rotation between the O-ring and the cavity, so as to make the sealing between the O-ring and the end cover and the wheel body more reliable.

The other is to increase the size of the floating seal ring cavity formed by the wheel body and the end cover, so as to reduce the pressure and friction resistance of the contact surface of each pair of floating seal rings, so as to reduce the heat generated by the contact friction of the floating seal rings.

Third, increase the diameter of the supporting wheel waist to increase the volume of the oil cavity at the wheel waist, so as to ensure sufficient lubrication.

The fourth is to increase the distance between the seat and cavity, increase the oil storage space at the floating seal ring, so as to ensure that the lubricating oil can effectively cool the floating seal ring.

Fifth, the oil groove is made on the inner wall of the copper sleeve to make its contact surface with the wheel shaft fully lubricated; at the same time, the oil hole is drilled on the inner wall of the wheel body to ensure that the lubricating oil can circulate.

After the above improvements, the roller can be fully lubricated and the floating oil seal is well sealed, which can fully meet the requirements of frequent turning and long-distance driving of small excavators.

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