1. Track malfunction
The track is loose or too tight
Fault phenomenon: Loose tracks can easily cause them to derail during operation, affecting the normal movement of the excavator. Tight tracks will increase the load on the walking device, accelerating the wear of components such as tracks, support wheels, and guide wheels.
Cause analysis: After prolonged use, the pins and bushings between the chain links of the track will wear out, causing the track to elongate and resulting in looseness. If the track is not adjusted according to the specified tension when installing the track, or the adjustment is improper during use, the track will be too tight or too loose.
Track shoes damaged
Fault phenomenon: The track shoes have broken, severely worn, and other issues. A broken track shoe can deteriorate the overall integrity of the track, and may even cause the track to malfunction; Overly worn track shoes can affect the walking stability and grip of excavators.
Cause analysis: In harsh working environments, such as working in rocky areas, track shoes are easily damaged by the impact of rocks. In addition, working under heavy loads for a long time will also accelerate the wear rate of the track shoes. If the tension of the track is not appropriate, it can also cause excessive local stress on the track shoes, thereby accelerating wear or causing damage.
Track derailment
Fault phenomenon: The track deviates from the normal walking track of the guide wheel, support wheel, etc., causing the excavator to be unable to walk normally.
Cause analysis: In addition to track looseness being a common cause, excavators may derail due to excessive speed during turning, improper operation on uneven road surfaces (such as one side of the track getting stuck in potholes), or uneven force on the track caused by undercarriage components (such as guide wheels and support wheels) malfunctioning.
2. Malfunctions of supporting wheels, idler wheels, and guide wheels
Not flexible in rotation
Fault phenomenon: These wheels do not rotate smoothly during operation, resulting in jamming. This will cause an increase in resistance when the excavator is moving, reduce the walking speed, and cause abnormal vibrations in the undercarriage.
Cause analysis: One of the main reasons is the damage to the bearings inside the wheels. Bearings may be damaged due to long-term exposure to high loads, lack of lubrication, or entry of impurities. In addition, damaged seals on the wheels can cause mud, water, dust, and other debris to enter the interior, which can also affect the normal rotation of the wheels.
Severe wear and tear
Fault phenomenon: Excessive wear on the rim, hub, and other parts of the supporting wheel, sprocket wheel, and guide wheel can affect their service life and performance. The worn wheels may not be able to support the weight of the excavator properly, causing the undercarriage to sink and affecting the stability of the excavator.
Cause analysis: Long term operation under heavy load conditions, uneven load distribution of the undercarriage (such as excavators often carrying heavy loads on one side), poor lubrication, and poor component quality may all lead to increased wear of these wheels.
3. undercarriage frame malfunction
deformation
Fault phenomenon: The undercarriage frame shows deformation such as bending and twisting. This will cause changes in the installation positions of various components of the excavator, affecting the overall performance of the excavator, such as reducing the accuracy of the working devices (boom, boom, etc.) and causing deviation during walking.
Reason analysis: Excavators may experience deformation of the undercarriage frame when subjected to significant external impacts (such as encountering hard obstacles during excavation, accidents such as overturning) or when working under heavy or unbalanced loads for a long time.
crackle
Fault phenomenon: Cracks appear on the frame, which is a more serious fault. Cracks will gradually expand with the operation of the excavator, ultimately leading to frame fracture and causing serious safety accidents.
Cause analysis: Factors such as material quality issues, poor welding processes (such as defects in the welding of the frame during manufacturing), or long-term exposure to alternating stress (such as frequent heavy load excavation and walking) may all lead to cracks in the frame.
4. Malfunctions in the walking motor and gearbox
Walking motor malfunction
Fault symptoms: Insufficient power of the walking motor, inability to drive the tracks or tires properly, unstable walking speed, etc.
Reason analysis: Insufficient or contaminated hydraulic oil is one of the common reasons. Insufficient hydraulic oil can cause the walking motor to not receive sufficient power, and contaminated hydraulic oil can damage the internal components of the motor. In addition, damage to the internal seals of the motor can cause hydraulic oil leakage, or wear on the bearings, gears, and other components of the motor, which can also affect its normal operation.
Gearbox malfunction
Fault phenomenon: The gearbox has abnormal noise, severe heating, and the output shaft cannot transmit power normally.
Cause analysis: Gear wear and tooth breakage inside the reducer are the main causes of the malfunction. This may be due to long-term overload operation, poor lubrication, or quality issues with the gears themselves. In addition, damage to the seals of the gearbox can cause lubricant leakage, which can also affect its normal operation and may accelerate gear wear.
5. undercarriage abnormal noise fault
Fault phenomenon
The excavator undercarriage makes abnormal noises during operation, such as "creaking", "clanging" or "buzzing" sounds. These abnormal noises may be intermittent or persistent, affecting the operator's judgment of the machine status, and may be signals of serious faults in certain components of the undercarriage.
Cause analysis
Component wear: When components such as supporting wheels, sprocket wheels, and guide wheels are severely worn, the clearance between their internal parts increases, resulting in abnormal friction sounds during operation. For example, after the bearing of the supporting wheel wears out, it will make a buzzing sound when rotating.
Foreign objects entering: If small stones, metal fragments, or other foreign objects enter between undercarriage components, such as getting stuck between tracks and support wheels, or entering the interior of guide wheels, they will produce collision sounds during component operation.
Loosening problem: The bolts, nuts, and other connecting parts on the undercarriage are loose. When the excavator is walking or working, the loose parts will collide or vibrate with each other, resulting in a "clunking" sound. For example, if the connecting bolts of the track shoes become loose, it can cause the track to produce impact sounds from loose parts during operation.
Poor lubrication: Insufficient lubrication of undercarriage components can cause dry friction between them, resulting in sharp "creaking" sounds. Especially in cold weather, if suitable low-temperature lubricants are not used, this situation is more likely to occur.
6. undercarriage electrical system failure (for excavators with electrical control undercarriage function)
Fault phenomenon
A malfunction in the electrical control system of the undercarriage may result in partial or complete loss of the excavator's walking function, such as inability to move forward, backward, or turn. At the same time, there may be undercarriage related fault indicator lights on the dashboard, displaying fault codes of the undercarriage electrical system, and other situations.
Cause analysis
Line problems: Aging, damage, or poor contact of wires are common causes of electrical system failures. During the operation of excavators, the undercarriage wires may be affected by factors such as vibration, friction, and humid environments, resulting in damage to the insulation layer of the wires and leading to short circuits, open circuits, and other situations. For example, a damaged wire connecting the walking motor can cause the motor to be unable to receive control signals properly.
Sensor malfunction: There are various sensors installed on the undercarriage, such as speed sensors, position sensors, etc., to monitor the operating status of the undercarriage. If the sensor malfunctions, it will send incorrect signals to the controller, causing confusion in the undercarriage control. For example, a speed sensor malfunction may result in inaccurate walking speed displayed on the dashboard or cause the automatic speed control function to fail.
Controller malfunction: The core of the undercarriage electrical control system is the controller, such as PLC (Programmable Logic Controller) or ECU (Electronic Control Unit). If the controller malfunctions, such as chip damage, program errors, etc., it will affect the electrical control function of the entire undercarriage. This situation may be caused by electromagnetic interference, abnormal power supply (such as high or low voltage), or quality issues with the controller itself.
