In modern machinery, sliding bearing is widely used in engineering machinery, metallurgical equipment, construction machinery, plastics processing equipment, hydraulic transmission systems, etc., because of its simple structure, high bearing capacity and excellent impact resistance. Unlike rolling bearings, sliding bearings rely on sliding friction and lubricating film between the shaft and the bearing surface to support movement; consequently, their performance is highly sensitive to lubrication conditions, fit accuracy and material properties.
In practice, sliding bearings are easy to wear, which is the main cause of equipment failure. From an engineering point of view, wear problems are rarely caused by a single factor, but by a combination of lubrication, load, material properties, installation and environmental conditions.
I. Lubrication Failure: the root cause of Plain Bearing Wear
The normal operation of ordinary bearings depends on the formation of a stable lubricating film to maintain fluid friction or boundary lubrication between the shaft and bearing surface. Once lubrication conditions is damaged, the direct contact betweenmetal and metal will accelerate the wear and tear.
Under actual operating conditions, lubrication failure usually manifests itself as insufficient oil supply, deterioration of lubricating oil (aging) or internal blockage of lubricating system. This is particularly common in equipment with high temperatures, heavy loads or prolonged continuous operation; in this case, lubricants are susceptible to oxidative degradation, which reduces the strength of the oil film, leading to localized dry friction and even bearings becoming stuck (commonly referred to as "burnt bearings").
Solving this problem requires a robust lubrication management system, including the selection of appropriate lubricants to ensure a continuous oil supply and regular maintenance of the lubrication system. For high-end equipment, automatic lubrication systems has become a key measure to minimize bearing wear.
II. Fatigue and structural failure of Overload Operation materials
Although sliding bearings have a high bearing capacity, they are designed to operate within a specific load range. When equipment is overload conditions for a long time, the bearing is subjected to constant high contact stresses, which leads to material fatigue.
This phenomenon is especially prevalent in heavy machinery such as mining crushers, metallurgical rolling mills and construction lifting equipment. Exposure to impact loads for a Prolonged time can lead to denting, plastic deformation and even surface peeling. From the engineering point of view, the key to solving the problem of overload lies not only in replacing bearings, but also in reanalyzing the load and optimizing the structure design according to actual operation. If necessary, choose material systems of higher strength,such as tin bronze or Babbitt alloy bearings, to improve overall bearing capacity.
III. Improper Clearance leads to rupture of oil film
The clearance design of sliding bearings directly influences the formation and stability of lubricating film. If the gap is too small, lubricating oil cannot enter the friction zone effectively, which leads the shaft system's operation local dry friction.
In practice, such problems often result from design errors or gap changes caused by prolonged wear. Once clearance exceeds the optimal limit, it will not only accelerate wear and tear, but also cause the vibration of the equipment to increase, operating noise to increase and accuracy to decrease.
Therefore, the design and maintenance of bearings must take into account thermal expansion, load fluctuations and wear compensation, and the actual operating clearances should be regularly monitored to ensure that they remain within the appropriate range.
IV. INTRODUCTION Abrasive Wear caused by Contaminant Ingress
In open or semi-open mechanical systems, the main cause of failure of sliding bearings is the entry of external pollutants into the lubrication system. Dust, metal debris and oxidation products form abrasive particles in lubricants; these hard particles interact repeatedly between the shaft and bearing, causing significant scratches and surface damage.
This wear usually takes the form of grooves or stripes and is accompanied by further deterioration in lubrication performance, forming a vicious circle. The problem is particularly acute in equipment operating in harsh industrial environments.
The key to solving this problem lies to improve system seal by adding filtration devices to the lubrication system and replacing the lubricating oil periodically to minimize the accumulation of impurities.
The selection of materials does not match the operating conditions.
The performance of sliding bearings depends to a large extent on the material systems used. Different materials exhibit obvious differences in abrasion resistance, bearing capacity, temperature resistance and self-lubrication.
If standard copper bushing materials are used under heavy load or high impact conditions, the rate of wear can be greatly accelerated, possibly leading to premature failure. In addition, in hot or corrosive environments, poor material selection can also lead to rapid performance degradation.
Therefore, in the course of engineering selection, material system should be selected according to actual operation. For example, tin bronze bearings are suitable for heavy loading applications, high-temperature alloys are suitable for high-temperature environments, and composite self-lubricating materials are suitable for poor lubrication.
VI. INTRODUCTION Local stress concentration due to Installation errors
Installation precision directly affects the service life of sliding bearings. Dislocation or deflection between shaft and bearing results in uneven load distribution and stress concentrations in local areas.
The problem may not be immediately apparent during the initial stage of operation of the equipment, but as operation continues, local wear and tear can accelerate rapidly, eventually leading to bearing failure.
Therefore, it is essential to ensure shaft alignment precision during installation --and to verify installation quality through airload testing to monitor vibration and temperature rise.
Conclusion:
In short, wear of sliding bearing is not caused by a single factor, but by the combination of lubrication conditions, load level, fitting precision, environmental pollution and material selection. In practical engineering application, in order to prolong the service life of sliding bearings and improve the operation stability of equipment, it is necessary to optimize the design, type selection, installation and maintenance.
For manufacturers, proper bearing selection and standardized maintenance management are often more important than simply upgrading material grades.
Frequently Asked Questions
Q 1: What are the main forms of failure of sliding bearings?
A: Adhesive wear due to lubrication failure is the most common, followed by abrasive wear and fatigue spalling.
Q2:Why are sliding bearings so dependent on lubrication?
A: Because they rely on oil film to prevent direct contact betweenmetal and metal, wear and tear can quickly increase once the film breaks.
Q3: How to tell if a sliding bearing has entered the failure stage?
A: Typical symptoms include abnormally high temperature, increased vibration, abnormal noise and significantly larger gaps.
Q4: What is the most suitable material for heavy-duty sliding bearings?
A: Tin bronze, Babbitt metal and some high-strength composites are ideal for heavy loading conditions.
Q5: How much impact does lubrication have on the service life of sliding bearings? A: Lubrication status is a key factor in determining service life. proper lubrication can greatly extend service life,often several times.
Q6: Do installation errors really affect bearing service life?
Answer: Yes. Deviations during installation can lead to local stress concentration, leading to premature failure due to wear and tear.