The truck-mounted crane is a type of cargo truck that incorporates lifting capabilities, offering the advantage of fulfilling both lifting and transportation tasks within a single vehicle. Its key components encompass the special vehicle chassis, the upper-mounted crane, the cargo box, the hydraulic system, and more. Today, let’s delve into the slewing bearing, a significant component of the crane.
In reality, this component known as the slewing bearing is not only applicable to truck-mounted cranes but also finds usage in various construction machinery models such as flatbed trucks. It represents a novel type of slewing product, primarily constituted by elements like worm gears, shells, and motors.
The slewing bearing serves as the principal component within the hydraulic system of the truck-mounted crane. Its rotation is facilitated by a full slewing mechanism driven by the gears of the slewing box, enabling unrestricted and arbitrary rotation. The slewing bearing is disc-shaped and lacks any angle limitations, allowing for rotation in any direction. Commonly, we refer to this as a ±360-degree rotation, representing a highly practical and convenient slewing structure. Generally, cranes with a capacity of 5 tons or above adopt a full slewing structure, while those within the 2-4 ton range mostly employ a rack and cylinder slewing structure.
When it comes to the utilization of the slewing bearing in truck-mounted cranes, several issues warrant attention:
Select the lubrication interval based on the conditions of the slewing bearing. Typically, for ball bearings, lubrication should be carried out once every 100 hours of operation. For column bearings, it is recommended to lubricate once every 500 hours of operation. For cranes that operate continuously in high-temperature and dusty environments, the lubrication interval should be appropriately shortened in accordance with the severity of the environmental conditions.
Let’s elaborate on this point. The operating environment has a significant impact on the performance and lifespan of the slewing bearing. High temperatures can cause the lubricant to degrade more rapidly, while dust can introduce abrasive particles that increase friction and wear. By adjusting the lubrication interval based on the specific conditions, the bearing can be better protected and its reliability maintained.
Grease serves multiple functions such as sealing, reducing friction or minimizing it to the greatest extent possible, and providing anti-corrosion protection. When replenishing the lubricating oil, it is essential to add an adequate amount of grease. In the case of a labyrinth seal, an excess of grease should overflow from the labyrinth structure.
Adequate greasing ensures that the sealing effect is maintained, preventing the ingress of contaminants and moisture. The anti-corrosion property of the grease helps protect the bearing from rust and other forms of corrosion, especially in harsh operating conditions.
Grease must be evenly distributed. When replenishing the lubricating grease, it is necessary to allow the slewing mechanism of the truck-mounted crane to rotate slowly.
This slow rotation ensures that the grease spreads uniformly across the contact surfaces, providing consistent lubrication and reducing the risk of localized wear or overheating. Uneven grease distribution can lead to imbalanced loading and premature failure of the bearing.
When cleaning the crane, take precautions to prevent steam or other liquids from entering the slideway.
Moisture or other fluids can cause corrosion and damage to the internal components of the slewing bearing, compromising its performance and longevity. Special care should be taken during the cleaning process to ensure that these areas remain dry and protected.
If the truck-mounted crane is going to be out of use for an extended period, it is crucial to lubricate the slewing bearing in advance.
This pre-lubrication helps prevent rust and oxidation during the period of inactivity, ensuring that the bearing remains in good condition and ready for immediate use when the crane is needed again.
After the truck-mounted crane has been in operation for a certain period, it is imperative to timely tighten the bolts of the slewing bearing. Generally, the inspection interval is set at 2-3 months. However, if the crane typically operates under heavy loads, the inspection cycle should be appropriately shortened.
Regular bolt tightening ensures the stability and integrity of the connection, preventing loosening that could lead to misalignment or excessive wear. The frequency of inspection needs to be adjusted based on the actual working conditions to address potential issues promptly.
There are numerous components within the truck-mounted crane. During the maintenance process, it is essential to give meticulous attention to each component to achieve truly comprehensive and effective maintenance.
By adhering to proper maintenance practices and paying close attention to the specific requirements of the slewing bearing, the performance, reliability, and lifespan of the truck-mounted crane can be significantly enhanced, reducing the likelihood of breakdowns and ensuring safe and efficient operation.
In conclusion, understanding the role and maintenance requirements of the slewing bearing is a vital aspect of maintaining the overall functionality and longevity of the truck-mounted crane. Through diligent care and attention to detail, the crane can continue to perform its duties reliably and contribute to successful lifting and transportation operations.
