As the main load-bearing structure of the crawler rotary excavator, the design and manufacturing quality of the rollers are directly related to the overall safety of the machine, especially in the large-tonnage crawler rotary excavator. Heavy round. The working conditions of the crawler rotary excavator are complicated. In some special lifting conditions or boom lifting conditions, only a part of the rollers are stressed. Therefore, the arrangement of rollers is sparse middle and dense ends. In order to meet the gradually increased weight of the crawler rotary excavator, the number of rollers and structural parameters have also increased accordingly. The rollers are installed at the bottom of the track frame and roll together with the bottom surface of the track shoe when walking. Most of the installation forms are open at small tonnages and closed at large tonnages.
Defect analysis of roll products
1. Many steel types do not meet the standards, and the heat treatment process is not very good.
2. The vicious competition in the market has led to the cutting-off of several important structures of the product, such as the reduction of the round diameter of the wheel body, the thinning of the supporting shaft, and the shortening of the length of the copper sleeve. The reduction in the circular diameter of the wheel body leads to the acceleration of the wheel linear velocity and the greater the frictional force on the sleeve.
3. The same is true for the thinning of the support shaft. Similarly, if the impact strength is not enough, the shaft will deform or break.
4. The copper sleeve acts as a friction. The copper layer does not come off easily until it is rolled and strapped. The normal copper layer exceeds 0.35 mm to reach the standard. The meaning of reducing the length of the copper sleeve is lost. Reducing the length is equivalent to reducing the stress area.
Support wheels are prone to problems.
Wheel wear; the reason is that the steel used is unqualified, or the material has low hardness during heat treatment and insufficient wear resistance.
Oil leakage; the bearing shaft has been rotating through the sleeve, and oil should be added to lubricate the wheel body. However, if the sealing ring is not good, it is easy to cause oil leakage. Therefore, the shaft and the sleeve are easily worn without lubrication, resulting in the product not being used.