Effects of Low Temperature on Slewing Bearings
The effects of low temperature on slewing bearings involve multiple aspects. These effects can seriously threaten the normal operation of equipment. By choosing appropriate solutions, the performance and reliability of slewing bearings in low – temperature environments can be effectively improved.
What is Low – Temperature Slew Bearing?
As a key component for various mechanical equipments to achieve rotational motion between components, slewing bearings are widely used in equipment such as cranes, wind turbines, and tunnel boring machines. In low – temperature environments, the performance and reliability of slewing bearings face many challenges. In – depth understanding of these effects and taking effective solutions are crucial for ensuring the normal operation of equipment and extending its service life.
Effects of Low Temperature on Slewing Bearings
Changes in Material Properties
Low temperature can alter the properties of the metal materials used in slewing bearings. Most metal materials become brittle at low temperatures, with a significant reduction in impact toughness. Taking commonly used bearing steel as an example, in a low – temperature environment, the crystal structure inside the material changes, making it difficult for dislocations to move. This greatly reduces the material’s ability to resist impact loads. When the equipment starts at low temperatures or is impacted during operation, the raceways, rolling elements, and other components of the slewing bearing are more prone to cracks. In severe cases, fractures may even occur, greatly affecting the load – bearing capacity and service life of the slewing bearing.
Decrease in Lubrication Performance
Low temperature seriously affects the lubrication effect of slewing bearings. Lubricating oil increases in viscosity and becomes less fluid at low temperatures, making it difficult to form a good oil film between the raceways and rolling elements. This not only increases the frictional resistance, resulting in increased energy consumption during equipment operation, but also exacerbates the wear between components. Under extremely low – temperature conditions, the lubricating oil may even solidify, completely losing its lubricating function. This causes the wear of the slewing bearing to rise sharply, affecting the rotational accuracy of the equipment and leading to unstable equipment operation, which cannot meet the working requirements.
Deterioration of Sealing Performance
The sealing device of slewing bearings is also affected by low temperatures. Sealing materials usually have a certain elasticity to ensure good sealing performance. However, in a low – temperature environment, the sealing materials harden, become brittle, and their elasticity decreases, resulting in reduced sealing performance. External impurities such as moisture and dust can easily penetrate into the interior of the slewing bearing, contaminating the lubricating oil and accelerating the corrosion and wear of components. If the moisture freezes after entering, it may also damage the sealing structure, further deteriorating the working environment of the slewing bearing.
Changes in Fitting Accuracy Caused by Thermal Expansion and Contraction
Each component of the slewing bearing undergoes dimensional changes due to thermal expansion and contraction at low temperatures. Different materials have different thermal expansion coefficients, which may affect the fitting accuracy between components. For example, the clearance between the raceway and the rolling elements may become smaller, increasing friction and wear. If the clearance is too large, it will affect the rotational accuracy, causing vibration and noise during equipment operation. In addition, thermal expansion and contraction may also cause the connections between the slewing bearing and other equipment components to loosen, affecting the overall stability of the equipment.
Solutions to Cope with the Effects of Low Temperature
Selection of Appropriate Materials
To cope with the low – temperature environment, materials with good low – temperature performance should be selected for manufacturing slewing bearings. For raceways and rolling elements, alloy steels containing elements such as nickel and manganese can be used. These alloying elements can effectively improve the low – temperature toughness of the material and reduce the brittle transition temperature of the material. For slewing bearings used in some extremely cold regions, special low – temperature alloy materials such as nickel – based alloys can also be considered. These materials can still maintain good mechanical properties at low temperatures. For seals, low – temperature – resistant rubber or plastic materials such as fluororubber and silicone rubber should be selected. These materials can maintain good elasticity and sealing performance at low temperatures.
Optimization of the Lubrication System
In response to the problem of reduced lubrication performance at low temperatures, the lubrication system of the slewing bearing needs to be optimized. First, lubricating oil with excellent low – temperature performance should be selected. It has a low pour point and a high viscosity index and can still maintain good fluidity at low temperatures. For example, polyalphaolefin (PAO) lubricating oil in synthetic lubricating oils performs better than mineral lubricating oils in low – temperature environments. Second, heating or heat – preservation devices can be used to increase the temperature of the lubricating oil to ensure its normal flow at low temperatures. In some large – scale equipment, a lubricating oil heating system can be installed to preheat the lubricating oil before the equipment starts. For small – scale equipment, heat – preservation materials can be used to wrap the lubricated parts to reduce heat loss.
Improvement of the Sealing Structure
To improve the sealing performance of slewing bearings at low temperatures, the sealing structure can be improved. A multi – layer sealing design can be adopted to increase the reliability of the seal. For example, multiple sealing lips can be set between the inner and outer rings of the slewing bearing, and sealant can be filled between the sealing lips to prevent the intrusion of external impurities. In addition, the seals should be regularly inspected and replaced to ensure their good performance. In a low – temperature environment, the aging rate of seals accelerates, so more attention needs to be paid to the maintenance of seals.
Compensation for the Effects of Thermal Expansion and Contraction
To compensate for the impact of thermal expansion and contraction on the fitting accuracy of slewing bearings, the thermal expansion coefficients of materials should be fully considered in the design stage, and the fitting clearances between components should be reasonably designed. Methods such as reserving clearances or adjusting shims can be used to ensure the normal fitting between components in a low – temperature environment. During the equipment installation and commissioning process, the fitting clearance of the slewing bearing should be adjusted according to the actual ambient temperature. The fitting accuracy of the slewing bearing can also be regularly detected to timely discover and solve problems caused by thermal expansion and contraction.
Price of Low – Temperature Slew Bearings
The prices of Low – Temperature Slew Bearings are affected by multiple factors. Material is one of the important factors. Special steels that can maintain their performance in low – temperature environments are required, and the high cost leads to an increase in price. The manufacturing process is also crucial. High – precision processing technology and strict quality control ensure the stability and reliability of the bearings at low temperatures, which increases the production cost and leads to a relatively high price. In terms of specifications and dimensions, special – specification or large – size Low – Temperature Slew Bearings are difficult to produce, and their prices will also increase accordingly.
Supplier of Low – Temperature Slew Bearings
Since its establishment, Ldb bearing Company has always shone with a unique luster. Rooted in Luoyang, Henan Province, a fertile ground for the bearing industry, the company has created many high – quality products with its professional design and R & D capabilities. The company’s product specifications are rich and diverse. Whether they are standard products or non – standard products, they all demonstrate exquisite craftsmanship. From the entry of raw materials into the factory to the output of finished products, strict process control and quality management are implemented at every step.