What are the causes of excavator carrier roller failure?
1. Wear and tear issues
Normal friction and wear
Reason analysis: During the working process, the excavator carrier roller always comes into contact with the track and undergoes relative motion. Due to the weight of the tracks and the friction generated during machine movement and operation, the surface of the rollers will gradually wear out. Especially when excavators frequently move, turn, or work on rough and uneven ground, the friction between the tracks and rollers will significantly increase. For example, in harsh working conditions such as mines, the rollers are subjected to high friction for a long time every day, and the wear rate will be faster.
Impact: After the surface of the roller wears down, it will change the contact state between it and the track. Excessive wear may result in a loose fit between the track and the idler, leading to a decrease in the stability of the track's operation, which can easily cause deviation, shaking, and other phenomena, thereby affecting the normal walking and operation of the excavator.
Wear and tear of foreign objects
Cause analysis: There are various foreign objects in the excavator operating environment, such as sand, metal fragments, wooden blocks, etc. These foreign objects may enter between the track and the idler, causing scratches and wear on the surface of the idler under the drive of the track. For example, at a building demolition site, broken bricks and concrete blocks are easily caught between tracks and rollers.
Impact: Foreign object wear not only accelerates the damage of the idler, but may also form pits or scratches on the surface of the idler, making the rotation of the idler less smooth. These pits and scratches will further exacerbate the wear of the track, forming a vicious cycle, and may lead to the failure of the rollers in a short period of time.
2. Bearing malfunction
Overload and fatigue damage
Reason analysis: Roller bearings need to withstand the weight of the roller itself, track pressure, and various forces generated during excavator walking and operation. If the excavator works under overweight loads for a long time or frequently performs high-intensity operations, the pressure borne by the bearings will exceed their design limit. For example, when lifting heavy materials or excavating hard rocks, bearings are subjected to significant axial and radial forces. Over time, the internal balls or raceways of the bearings may experience fatigue wear, deformation, or even rupture.
Impact: After the bearing is damaged, the roller will produce abnormal noises during rotation, such as "buzzing" or "creaking" sounds. At the same time, the rotational resistance of the rollers will increase, and in severe cases, it can cause the rollers to get stuck, making the tracks unable to operate normally and affecting the walking function of the excavator.
Poor lubrication
Reason analysis: Roller bearings require good lubrication to reduce friction and wear. If the lubricating grease is insufficient, deteriorated, or contaminated, the lubrication effect of the bearing will deteriorate. For example, excavators working in high temperature environments may experience loss or deterioration of lubricating grease due to excessive temperature; In environments with high levels of dust, dust can easily enter the interior of bearings and contaminate the lubricating grease.
Impact: Poor lubrication can lead to an increase in the friction coefficient inside the bearing, causing an increase in bearing temperature and accelerating bearing wear. Long term poor lubrication can significantly shorten the service life of bearings and may cause other failures, such as seal damage.
3. Sealing failure
Aging and damage of seals
Reason analysis: The sealing components of the roller are usually made of materials such as rubber or plastic, and over time and under the influence of the usage environment, the sealing components will gradually age. High temperature, chemical substances (such as oil stains, acidic and alkaline substances, etc.), ultraviolet radiation, and prolonged mechanical stress can accelerate the aging process of seals. In addition, seals may also be damaged due to external impact, excessive compression, or improper installation. For example, when an excavator crosses obstacles, the rollers may experience severe vibrations, causing the seals to tear.
Impact: After the seal fails, impurities such as dust and moisture from the outside can easily enter the interior of the roller, contaminate the bearings and other components, and also cause internal grease leakage. This not only leads to increased wear of bearings and other components, but may also affect the normal rotation of the rollers and reduce their service life.
4. Improper installation and adjustment
Installation accuracy issue
Reason analysis: If the roller is not installed according to the correct installation process, its installation accuracy cannot be guaranteed. For example, if the axis of the roller is not parallel to the running direction of the track, or if the spacing between the rollers does not meet the design requirements, it will result in uneven force distribution between the rollers and the track. This may be due to reasons such as unskilled installation personnel, inaccurate installation tools, or poor installation environment.
Impact: Insufficient installation accuracy can cause excessive pressure on the roller locally, accelerating wear. At the same time, uneven stress may also cause damage to the bearings of the rollers, seal failure, and affect the normal operation of the tracks, resulting in shaking, deviation, and other phenomena during the excavator's walking process.
Improper tension adjustment
Reason analysis: The tension of the track has a significant impact on the working state of the rollers. If the tension of the track is too high, the pressure borne by the rollers will increase, accelerating the wear of the rollers and bearing damage; If the tension of the track is too low, good contact between the track and the rollers may not be maintained, resulting in unstable track operation. The main reason for improper tension is not following the technical specifications of the excavator when adjusting the track tension.
Impact: Improper track tension can affect the service life of rollers and may cause safety issues such as track derailment, affecting the normal use of excavators.
How to improve the service life of excavator carrier rollers?
1. Optimize the working environment
Cleaning up debris on the work site: Before excavator operation, the site should be thoroughly cleaned to remove foreign objects that may enter between the tracks and rollers, such as stones, metal fragments, wooden blocks, etc. If any debris is found piled up near the tracks during the homework process, it should be cleaned up in a timely manner. For example, at the site of building demolition, assign a dedicated person to clean up broken bricks, concrete blocks, etc., which can reduce the wear and tear of the rollers caused by foreign objects.
Control dust and soil in the work environment: Dust and soil are common factors in the working environment of excavators. Excessive dust can easily enter the sealing area of the roller, affecting the sealing effect and causing internal component wear. After working in a dusty environment, the excavator should be cleaned promptly, especially in the area around the rollers. For soil that is prone to adhere in humid environments, it is also necessary to clean it in a timely manner to avoid increasing the rotational resistance of the rollers. For example, in dusty areas such as coal mining, measures such as spraying water to reduce dust can be taken, and excavators should be regularly washed.
2. Operate the excavator correctly
Avoid overload operation: The rollers of the excavator are designed according to a certain load capacity. Operators should strictly follow the rated load of the excavator to avoid subjecting the rollers to excessive loads for a long time. For example, when excavating hard foundations or transporting overweight materials, attention should be paid to arranging the weight of excavation and transportation reasonably to avoid exceeding the design load. Proper operation can reduce the burden on the rollers and extend their service life.
Smooth operation reduces impact: During the walking and operation of the excavator, efforts should be made to maintain a smooth motion. Avoid aggressive operations such as sudden acceleration, sudden braking, and sudden turns. Because these actions will cause the roller to experience a huge instantaneous impact force. For example, when an excavator makes a quick turn, one side of the idler roller will experience significant lateral force, which can easily lead to bearing damage and surface wear of the idler roller. The operator should operate the excavator slowly and steadily, allowing the rollers to evenly bear the load.
3. Strengthen maintenance and upkeep
Regular inspection and cleaning of rollers: Regularly (e.g. every 100 to 200 hours of operation) inspect and clean the rollers. Check the surface of the roller for wear, dents, scratches, etc., and promptly clean the roller surface and surrounding dust, dirt, and other impurities. For rollers with severe surface wear, they should be repaired or replaced in a timely manner.
Check and replace lubricating grease: Lubrication of roller bearings is crucial. Regularly (every 300 to 500 working hours) check the oil level and quality of the lubricating grease. If insufficient lubricating grease is found, it should be added in a timely manner; If the lubricating grease is contaminated or deteriorated, such as mixed with dust, water, or metal particles, it should be replaced in a timely manner. At the same time, high-quality lubricating grease that meets the equipment requirements should be used to ensure good lubrication effect.
Check and maintain seals: Seals are key components that prevent impurities from entering the interior of the rollers and grease leakage. Regularly (every 500 to 800 working hours) inspect the condition of the seals to see if there is any aging, hardening, cracking, or deformation. If damaged seals are found, they should be replaced promptly. When installing new seals, make sure they are installed correctly to avoid damaging the seals due to improper installation. In addition, an appropriate amount of lubricating grease can be applied around the seal to improve its sealing performance.
Check and adjust track tension: Regularly (every 200 to 300 hours of operation) check if the track tension is appropriate. Excessive or insufficient track tension can affect the service life of the rollers. Professional tools can be used to adjust the track tension according to the technical specifications of the excavator, ensuring good contact between the track and the idler roller, and enabling the idler roller to work normally.
4. Choose high-quality rollers and accessories
Choose high-quality branded products: When purchasing or replacing rollers, try to choose well-known brands with reliable quality. High quality brand rollers usually use high-quality materials and advanced manufacturing processes, and their wear resistance, internal component quality, and reliability are relatively high. For example, some high-end brand rollers have a special wear-resistant coating on their surface, which can effectively resist wear and corrosion.
Ensuring the quality of accessories: In addition to the roller itself, the quality of its accessories (such as bearings, seals, etc.) is also important. The use of high-quality accessories can ensure the overall performance of the rollers. When replacing accessories, choose products that match the roller model and meet the equipment requirements. For example, high-quality bearings can withstand greater loads and have good wear resistance and sealing properties; High quality seals can effectively prevent impurities from entering and grease leakage, thereby extending the service life of the rollers.
How much does it cost to replace the excavator carrier roller?
The cost of replacing excavator idlers mainly consists of two parts: the price of the idlers themselves and the labor cost of replacement. The following is a detailed introduction:
Roller price
Different brands and models: Excavators of different brands and models have significant differences in the prices of their rollers. Generally speaking, the prices of excavator carrier rollers from domestic brands are relatively low, with individual rollers of ordinary models priced between 100 and 300 yuan; However, excavators from internationally renowned brands such as Komatsu and Caterpillar have higher prices for their original rollers, typically ranging from 500 to 1000 yuan per roller. For example, the rollers of the Komatsu PC200 excavator are priced at approximately 800 yuan per genuine factory product
Different types: There are various types of rollers, such as flat rollers, groove rollers, self-aligning rollers, etc. The prices of different types of rollers also vary. Taking common flat rollers and groove rollers as examples, groove rollers are generally about 20% or 50% more expensive than flat rollers due to their relatively complex structure. The commonly used flat idlers in some small belt conveyors may cost between 50 and 150 yuan, while the corresponding groove idlers cost between 80 and 250 yuan
Labor cost
Regional differences: The economic development level and labor costs vary in different regions, resulting in significant differences in the labor costs for replacing excavator carrier rollers. In economically developed first tier cities such as Beijing, Shanghai, Guangzhou, etc., labor costs are relatively high, generally ranging from 200 to 300 yuan per hour; In some second - and third tier cities, labor costs are relatively low, around 100 to 200 yuan per hour. Taking Nanjing as an example, the labor cost for replacing excavator carrier rollers is generally between 150 yuan and 250 yuan
Repair shop type: The labor cost of 4S shops is usually higher than that of ordinary repair shops. Due to their professional equipment, technology, and relatively standardized service processes, 4S stores generally charge labor costs ranging from 200 to 300 yuan per hour; The hourly rate for regular repair shops is around 100 to 200 yuan.
