The maintenance of excavator undercarriage is a key link to ensure the normal operation and prolong the service life of excavators. The following are some maintenance points:
Daily inspection
1. Appearance inspection
Before using the excavator every day, the undercarriage should be visually inspected. Check if there are obvious collision marks, deformations, or cracks on the undercarriage. For example, if there are cracks in the main beam of the undercarriage, it may affect the structural strength of the entire undercarriage. During inspection, a flashlight can be used to carefully examine the connection parts and easily damaged edges of each component of the undercarriage.
Check if the protective coating on the undercarriage is intact. Protective coatings can prevent rusting and corrosion of undercarriage metal components. If peeling or damage to the coating is found, it should be repaired in a timely manner to avoid exposing the metal to a humid environment.
2. Component inspection
Check the walking mechanism of the undercarriage, including the tracks and tires (if it is a wheeled excavator). For tracked excavators, it is necessary to check the tightness of the tracks. Loose tracks can cause derailment, while tight tracks can increase wear on the walking mechanism. Under normal circumstances, the track sag should be between 30 and 50 millimeters. It can be determined by parking the excavator on a flat surface and measuring the distance of the track sagging with a ruler.
Check if the pins and bushings of the track are worn. Severely worn pins and bushings may cause an increase in track pitch, thereby affecting the normal operation of the tracks. At the same time, it is necessary to check whether the track shoes are broken or excessively worn. For tire excavators, it is necessary to check whether the tire pressure is normal and whether there are any damages such as cuts or bulges on the tire surface.
Check the support wheels, sprocket wheels, and guide wheels of the undercarriage. The flexibility of the rotation of these wheels is crucial. If the wheels do not rotate flexibly, additional friction will be generated, accelerating the wear of components. You can manually rotate the wheels to check their flexibility and check if the seals on the wheels are intact to prevent lubricant leakage.
Cleaning work
1. Regularly clean up soil and debris
During the operation of excavators, the undercarriage is easily contaminated with soil, sand, and other debris. After each job, try to clean the undercarriage as much as possible. High pressure water guns can be used to flush the undercarriage, but care should be taken to avoid direct water entering electrical and hydraulic components. For stubborn soil that is difficult to wash away, tools such as shovels can be used to clean it first.
For excavators that work in humid environments or by the sea for a long time, it is even more important to pay attention to the cleanliness of the undercarriage. Because salt and humid air can accelerate the corrosion of the undercarriage. After cleaning, ensure that the undercarriage is completely dry and allow the excavator to be parked in a well ventilated area for a period of time.
2. Clean lubricating oil and stains
Some components of the undercarriage, such as support wheels and guide wheels, may have lubricating oil seeping out. If these lubricating oils mix with dirt and other debris, they can form sludge, which affects the normal heat dissipation and operation of the components. When oil sludge is found, it should be cleaned up in a timely manner. Special cleaning agents can be used to dissolve the sludge before rinsing.
Lubrication and maintenance
1. Choose the appropriate lubricant
Select appropriate lubricating oil and grease based on the working conditions and requirements of excavator undercarriage components. For example, for components such as supporting wheels and sprocket wheels, lubricating grease with good wear resistance and extreme pressure performance is generally used. Excavators working in high-temperature environments need to choose lubricants that are resistant to high temperatures.
2. Regular lubrication
According to the user manual of the excavator, regularly lubricate the undercarriage components. For tracked excavators, it is usually necessary to regularly lubricate the pins and bushings of the tracks. Special lubrication tools can be used to inject grease between the pin and the bushing. For supporting wheels, idler wheels, and guide wheels, it is also necessary to regularly check the content of their lubricating grease and replenish it in a timely manner. Generally speaking, a comprehensive undercarriage lubrication is required every certain number of working hours (such as 100 to 200 hours).
Tightening bolt inspection
There are many bolts on the undercarriage used to connect various components, such as the connecting bolts between the track shoes and the chain rail joints, and the connecting bolts between the supporting wheels and the undercarriage frame. These bolts may loosen due to vibration during the operation of the excavator.
Regularly use tools such as wrenches to check the tightness of bolts. When checking, tighten according to the specified torque value. Excessive torque may damage bolts or components, while insufficient torque cannot guarantee the reliability of the connection. It is generally recommended to check the tightening of undercarriage bolts every 50 to 100 hours of work.
While checking the tightness of the bolts, it is also necessary to check for any signs of damage to the bolts, such as thread wear, deformation of the bolt head, etc. If damaged bolts are found, they should be replaced in a timely manner, and the replaced bolts should meet the specifications of the excavator.
Rust prevention treatment
1. Maintenance and touch up of anti rust paint
Regularly check the condition of the undercarriage anti rust paint. If a small area of anti rust paint peeling is found, the rust on the surface of the undercarriage can be cleaned first. You can use sandpaper to polish the rusted area until a metallic luster is exposed, and then clean it with a cleaning agent to ensure that the surface is free of oil stains and impurities. Afterwards, apply the same type of paint as the original undercarriage anti rust paint for touch up. When repairing, pay attention to applying evenly to avoid uneven thickness or paint flow.
For cases of extensive damage to the anti rust paint, consider repainting the undercarriage. Before repainting, it is necessary to thoroughly clean and remove rust from the undercarriage. It is best to remove some detachable components of the undercarriage and paint them separately to ensure the painting effect. After painting, the undercarriage should be thoroughly dried and cured in a well ventilated and dry environment.
2. Use rust inhibitor
In addition to anti rust paint, rust inhibitors can also be used to enhance the anti rust ability of the undercarriage. Some rust inhibitors can be directly sprayed onto the surface of the undercarriage, forming a protective film on the metal surface to prevent oxygen and moisture from coming into contact with the metal. When using rust inhibitors, follow the requirements of the product manual to ensure even application, and pay attention to the expiration date of the rust inhibitor. Regularly reapply.
Regular in-depth inspection and maintenance (based on working hours or usage)
1. Component wear assessment
After the excavator has been working for a certain period of time (e.g. every 1000 to 2000 hours), conduct a deep inspection of the undercarriage components. Check the wear level of components such as supporting wheels, idler wheels, and guide wheels using professional measuring tools. For example, measuring the thickness of the rim of a supporting wheel, if the wear exceeds the specified limit value (usually specified in the manual), the supporting wheel needs to be replaced. For track shoes, their wear should also be checked, as severely worn track shoes can affect the walking stability of the excavator.
Check if there are fatigue cracks on the undercarriage frame. Non destructive testing techniques such as magnetic particle inspection or ultrasonic inspection can be used. These technologies can detect hidden cracks inside the frame and promptly identify potential safety hazards. If cracks are found on the frame, repair or replacement measures should be taken according to the severity of the cracks.
2. System inspection and adjustment
Conduct a comprehensive inspection of the undercarriage' walking system. Check the working condition of components such as the walking motor and gearbox. For example, check whether the output shaft of the walking motor is loose, whether the gears of the reducer are worn, etc. If any problems are found, they should be repaired or replaced in a timely manner.
Adjust parameters such as track tightness based on the wear of the undercarriage. If some components of the undercarriage are replaced, such as new support wheels or track shoes, it is also necessary to test and adjust the overall performance of the undercarriage to ensure that the excavator undercarriage can work properly.
