What are the disadvantages of sliding bearings?

Features and advantages of sliding bearings: 1) High load-bearing capacity； 2) Stable and reliable operation with low noise ； 3) Small radial dimension ； 4) High precision ； 5) During fluid lubrication, friction and wear are low ； 6) The oil film has a certain vibration-damping capacity. Disadvantages: 1) Non-fluid friction sliding bearings experience high friction and severe wear. 2) Fluid friction sliding bearings find it difficult to achieve fluid friction under conditions of startup, operation, high loads, and high rotational speeds ； 3) Fluid friction, as well as the design, manufacturing, and maintenance costs of sliding bearings, are relatively high.

Advantages of sliding bearings: 1. Simple structure, easy to install and remove； 　　2. High load-bearing capacity, suitable for heavy-duty applications ； 　　3. High operating precision, low play, balanced operation, and no noise ； 　　4. Capable of withstanding impact and vibration loads ； 　　5. Long lifespan, suitable for high speeds ； Disadvantages of sliding bearings: 1. They are unable to maintain an adequate supply of lubricating oil; once the lubricant level drops, severe wear occurs immediately, leading to failure ； 2. Non-liquid friction sliding bearings have high friction losses ； 3. Liquid friction sliding bearings require high standards in terms of design, manufacturing, lubrication, and maintenance, and are costly. 　　

Additional disadvantages of sliding bearings: Large sliding bearings require substantial cooling. Composite bearings wear out quickly and are prone to damage during installation and removal.

I would like to ask what the characteristics of rolling bearings are? What are the advantages and disadvantages of sliding bearings compared to rolling bearings?

Poor lubrication, high resistance, and rapid wear

Sliding bearings have high load-bearing capacity, but they require proper lubrication and are prone to wear. Rolling bearings (with point or line contact) are easier to maintain and have a longer service life; however, if of poor quality, they can generate noise. It is recommended to use SKF bearings from Sweden, as they are of high quality and offer higher precision compared to those produced domestically

Features of rolling bearings: Compared to sliding bearings, rolling bearings have the following advantages – 1. The friction coefficient of rolling bearings is lower than that of sliding bearings, resulting in higher transmission efficiency. The friction coefficient of conventional sliding bearings is 0.08–0.12, whereas that of rolling bearings is only 0.001–0.005; 2. Rolling bearings have been standardized, serialized, and generalized, making them suitable for mass production and supply, as well as easy to use and maintain ； 3. Rolling bearings are made of bearing steel and undergo heat treatment; as a result, they not only possess high mechanical properties and a long service life, but also help to save on the expensive non-ferrous metals used in manufacturing sliding bearings ； 4. The internal clearance of rolling bearings is very small, and the machining precision of the various components is high; therefore, their operating precision is also high. At the same time, the stiffness of the bearing can be increased by applying preload. This is very important for precision machinery ； 5. Certain rolling bearings can withstand both radial and axial loads; therefore, the structure of the bearing supports can be simplified ； 6. Due to the high efficiency of rolling bearing drives and low heat generation, oil consumption can be reduced, making lubrication and maintenance simpler ； 7. Rolling bearings can be easily applied to uranium in any orientation in space. However, everything has two sides; rolling bearings also have certain disadvantages. The main ones are: 1. Rolling bearings can bear loads to a much lesser extent than sliding bearings of the same volume, which is why rolling bearings have larger radial dimensions. Therefore, in applications subject to high loads and where compact structural dimensions are required (such as in internal combustion engine crankshaft bearings), sliding bearings are commonly used ； 2. Rolling bearings generate significant vibration and noise, especially toward the end of their service life; therefore, in applications that require high precision and where vibration is not acceptable, rolling bearings are not suitable – sliding bearings are generally a better choice in such cases. 3. Rolling bearings are particularly sensitive to foreign objects such as metal shavings; once such objects enter the bearing, it can result in intermittent heavy vibration and noise, as well as premature damage. Furthermore, rolling bearings are also prone to premature failure due to metal inclusions and other impurities. Even without early damage, the lifespan of rolling bearings is limited to a certain extent. In short, the service life of rolling bearings is shorter than that of sliding bearings. However, compared to sliding bearings, rolling bearings have their own advantages and disadvantages, and are suitable for certain applications; therefore, they cannot completely replace each other, and each continues to develop in its own direction to expand its scope of use. However, due to the outstanding advantages of rolling bearings, there is a trend of later entrants overtaking them. At present, rolling bearings have evolved into the primary type of support in machinery, with their use becoming increasingly widespread

For the slurry pumps of Factory 525, can a cracked DF2 pump casing be welded? Please, experts, give me some advice.

Although sliding bearings have their drawbacks, they are an essential component for most large-load equipment. The radial load-carrying capacity is certainly beyond that of ordinary rolling bearings, and wear issues can be addressed through well-designed babbitt linings and a sufficient lubrication film. Sliding bearings are divided into fixed pads and tilting pads; I have also encountered a type of sliding bearing called the flex pad type, whose price and performance lie somewhere between those of the two aforementioned types. When it comes to avoiding wear, companies with advanced technology abroad still use electromagnetic suspension bearing technology.

Disadvantages of sliding bearings: A proper clearance must exist between the bearing shells and the shaft in sliding bearings. Good oil retention conditions must be established for the bearing shells of sliding bearings. Prone to wear. When the lubrication is poor, it can easily cause the bearings to sinter (at constant rotational speed).