Tag Archive for: Slewing Bearings

Slewing bearings is a crucial component of mechanical equipment, and its dynamic characteristics have a significant impact on the performance of the equipment. It consists of an inner ring, an outer ring, rolling elements, and a cage. It has been found that the force and vibration characteristics vary under different working conditions.

What is Slew Bearing in the Dynamics?

Slewing bearings are widely used in equipment such as cranes, excavators, and wind turbines. They are responsible for transmitting axial forces, radial forces, and overturning moments. Their dynamic characteristics are of great significance for the stability, reliability, and service life of the equipment. Under different working conditions, the stress and motion states of slewing bearings are complex and variable. In – depth research on their dynamic characteristics helps to accurately grasp the working performance, provides strong support for optimized design, and thus enhances the competitiveness of the equipment.

Working Principle and Structural Types of Slewing Bearings

A slewing bearing usually consists of an inner ring, an outer ring, rolling elements, and a cage. The inner ring is connected to the fixed part of the equipment, and the outer ring is connected to the slewing part. When the equipment is operating, relative slewing motion is achieved through the rolling of the rolling elements between the raceways of the inner and outer rings, while bearing loads in different directions.

Common slewing bearings include single – row four – point contact ball type, double – row non – uniform diameter ball type, and crossed roller type. The single – row four – point contact ball type has a simple structure and low cost, and can withstand large axial forces and overturning moments. The double – row non – uniform diameter ball type has a strong load – bearing capacity and is suitable for heavy – load working conditions. The crossed roller type has good rigidity and high precision and is often used in equipment with strict requirements for slewing accuracy.

Analysis of the Dynamic Characteristics of Slewing Bearings under Different Working Conditions

Static Working Conditions

Under static working conditions, slewing bearings mainly bear the self – weight of the equipment, the weight of fixed components, and external loads in a stationary state. At this time, the stress distribution at the contact points between the rolling elements and the raceways depends on the magnitude and direction of the load. Through the elastic contact theory, the contact stress and deformation can be calculated, providing a theoretical basis for determining the load – bearing capacity and fatigue life of the slewing bearing.

Dynamic Working Conditions

Uniform Rotation Working Conditions

During uniform rotation, in addition to static loads, slewing bearings are also subjected to centrifugal forces and frictional forces. The centrifugal force causes additional pressure on the raceways by the rolling elements, and the frictional force affects the smoothness of rotation. Using the multi – body dynamics theory, a dynamic model of the slewing bearing is established to analyze its motion parameters and stress changes during uniform rotation, such as the rotational speed, acceleration of the rolling elements, and contact force fluctuations.

Starting and Braking Working Conditions

During the starting and braking processes, slewing bearings will generate impact loads. When starting, the driving torque overcomes the static friction force to accelerate the rotation of the slewing part; when braking, the braking torque decelerates the slewing part until it stops. In these two processes, the impact load may cause an instantaneous increase in the contact stress between the rolling elements and the raceways, affecting the service life of the slewing bearing. By using a dynamic simulation software to simulate the starting and braking processes, the magnitude and action time of the impact load are analyzed, providing a reference for optimizing the braking and starting strategies.

Variable Load Working Conditions

In actual work, slewing bearings often bear variable loads. For example, when a crane hoists a heavy object, the magnitude and direction of the load change with the working state. Variable loads can cause vibrations in slewing bearings, and in severe cases, affect the normal operation of the equipment. Modal analysis and response spectrum analysis methods are used to study the vibration characteristics of slewing bearings under variable loads, determine their natural frequencies and vibration responses, and provide a direction for structural optimization.

Research Methods

Theories such as material mechanics, elasticity mechanics, and contact mechanics are used to derive the calculation formulas for the stress and deformation of slewing bearings under different working conditions. Combined with the basic equations of dynamics, a dynamic model of the slewing bearing is established to analyze its motion and stress characteristics. Theoretical analysis provides a basis and direction for subsequent research.

Professional software such as ANSYS and ADAMS is used to establish a virtual model of the slewing bearing. The working states under different working conditions are simulated to obtain detailed dynamic parameters such as stress, strain, displacement, velocity, and acceleration. By changing the model parameters, the influence of various factors on the dynamic characteristics is studied, providing data support for optimized design.

An experimental platform for slewing bearings is built to simulate actual working conditions for loading tests. Sensors are used to measure parameters such as the stress, vibration, and rotational speed of the slewing bearing. The experimental results can verify the accuracy of theoretical analysis and simulation, and provide a basis for improving the research model.

Optimization Design Strategies Based on Dynamic Characteristics

Structural Parameter Optimization

According to the research results of dynamic characteristics, the structural parameters of slewing bearings are optimized, such as the number and diameter of rolling elements, and the radius of curvature of the raceways. Through optimization, the contact stress can be reduced, the vibration can be decreased, and the load – bearing capacity and service life can be improved.

Material Selection Optimization

Appropriate materials are selected to improve the strength, hardness, and wear resistance of slewing bearings. The use of new materials or surface treatment of existing materials can improve their mechanical properties to meet the requirements of different working conditions.

Manufacturing Process Improvement

The manufacturing process is optimized to improve the machining accuracy and assembly quality of slewing bearings. High – precision machining and assembly can reduce the gaps and errors between components, reduce vibration and noise, and enhance the dynamic performance of slewing bearings.

The Price of Slewing Bearings

There are many factors affecting the price of slewing bearings. Firstly, the specifications and dimensions are key factors. Large – sized slewing bearings with high load – bearing capacity are expensive due to high material consumption and complex processes. Secondly, the accuracy grade is also important. High – precision products are often more expensive due to strict processing requirements. Moreover, the quality of materials has a significant impact. Slewing bearings made of high – quality materials have good performance and a correspondingly higher price. In addition, the reputation of brand manufacturers, market supply – and – demand relationships, and surface treatment and protection requirements can all cause fluctuations in the price of slewing bearings. Products with special surface treatments usually have a higher price.

Supplier of Slewing Bearings

Since its establishment in 1999, LDB bearing company has been shining in the bearing manufacturing field. It is located in Luoyang, Henan Province, which is a bearing production base in China. Taking advantage of favorable geographical location and gathering industry elites, its slewing bearings, slewing drives and other products, with precise design and high – quality material selection, have high performance and reliability. This is best proved by its ISO9001:2015 certification and German TUV certification. Its products are exported to 73 countries and regions, serving many fields such as industrial robots and solar power generation equipment. It has partnered with many well – known international enterprises. From pre – sales customization, in – sales strict control to after – sales worry – free service, LDB bearing company interprets the responsibility of an industry model with comprehensive services, and is worthy of being a dazzling star in the bearing industry.

To ensure the reliability of slewing bearings in medical equipment, multiple aspects need to be considered comprehensively. Quality control should be strict, and reliability can also be guaranteed through redundant design and life assessment.

What are Slewing Bearings in Medical Equipment?

Slewing bearing for medical equipment are key mechanical components used in medical devices. They mainly function to connect and support rotatable parts, enabling the equipment to achieve smooth and precise slewing motion. For example, in large – scale imaging diagnostic equipment such as CT scanners and magnetic resonance imaging (MRI) machines, the slewing support ensures the stable rotation of the scanning components, accurately obtaining images of different angles of the human body, which helps doctors make accurate diagnoses. It features high precision to guarantee the accuracy of equipment operation, high load – bearing capacity to support heavy components of the equipment, and excellent reliability and durability, reducing equipment failures and maintenance costs. It is of great significance for the normal operation of medical equipment and diagnostic accuracy.

Material Selection

Biocompatibility:For slew bearings in medical equipment that come into direct or indirect contact with the human body, the biocompatibility of the material is of utmost importance. Medical – grade stainless steel, for instance, has good strength and corrosion resistance, and it causes minimal irritation to human tissues. Titanium alloy has even more advantages. Not only does it have excellent biocompatibility, but it also has a low elastic modulus, which can better match human bones and reduce the stress – shielding effect. Ceramic materials such as alumina and zirconia ceramics, in addition to good biocompatibility, have extremely high hardness and wear resistance, which can effectively reduce the generation of wear particles and minimize potential harm to human tissues. In addition, some biocompatible polymer materials are also applied to specific medical bearings, as they possess good flexibility and chemical stability.

Corrosion Resistance:The medical environment contains various corrosive substances, such as hydrogen peroxide and chlorine – containing disinfectants used for disinfection. The bearing material must have excellent corrosion resistance to prevent surface corrosion. For example, nickel – based alloys are used in some medical equipment bearings with high corrosion – resistance requirements due to their good anti – corrosion properties. Even when in long – term contact with corrosive substances or in a humid environment, these materials can maintain the integrity and performance of the bearings, avoiding problems such as increased surface roughness and dimensional changes caused by corrosion, thus ensuring the reliability of the bearings.

Mechanical Properties:Different medical equipment has varying requirements for the mechanical properties of bearings. In high – load medical equipment such as large – scale radiotherapy equipment, the bearings need to withstand huge weights and dynamic loads. Therefore, the material is required to have high strength and toughness to prevent fracture or deformation during operation. For some high – precision diagnostic equipment, such as the fine – tuning mechanism bearings of optical microscopes, in addition to a certain strength requirement, more emphasis is placed on the hardness and wear resistance of the material to ensure that it can achieve precise micro – displacement adjustment and maintain accuracy during long – term use.

Precision Requirements

Dimensional Accuracy:The dimensional accuracy of bearings in medical equipment directly affects the overall performance of the equipment. For example, in the joint parts of surgical robots, the dimensional tolerances of the inner and outer diameters of the bearings usually need to be controlled within a few microns to ensure the motion accuracy of the robotic arm. If the dimensional accuracy is insufficient, it may lead to joint looseness or poor movement, affecting the accuracy of surgical operations. Similarly, in some precision medical testing instruments, the width accuracy of the bearings also needs to be strictly controlled to ensure their fit accuracy with other components, enabling stable operation and accurate measurement.

Rotational Accuracy:For medical equipment that relies on high – speed rotation to function, such as CT scanners and centrifuges, the rotational accuracy of the bearings is crucial. Take high – end CT scanners as an example. The bearings of their rotating parts need to ensure that the radial and axial run – outs during high – speed rotation are controlled within the micron level. This can ensure that the relative positions of the X – ray source and the detector remain precisely unchanged, thus obtaining high – quality scan images. If the rotational accuracy does not meet the standard, problems such as blurred and distorted images will occur, affecting doctors’ accurate judgment of the condition.

Lubrication and Sealing

Lubrication Method:Selecting the appropriate lubrication method and lubricant is one of the key factors in ensuring the reliability of bearings. For some low – speed and light – load medical equipment bearings, grease lubrication is a commonly used method. High – quality lubricating grease has good adhesion and lubrication performance, which can form a uniform oil film on the bearing surface, reducing friction and wear. For high – speed and heavy – load bearings, such as those in the transmission systems of some large – scale medical equipment, oil mist lubrication or circulating oil lubrication may be adopted to provide better heat dissipation and lubrication effects. At the same time, the lubricant must meet medical safety standards, be non – toxic, odorless, and have good chemical stability, and should not deteriorate or produce harmful substances during long – term use.

Sealing Design:A reliable sealing structure is crucial for preventing lubricant leakage and the entry of external contaminants into the bearings. In medical equipment, common sealing methods include mechanical seals and lip seals. For example, in some medical equipment that needs to operate in a sterile environment, a double – sealing structure is used. This can not only effectively prevent lubricant leakage from contaminating the environment but also prevent external bacteria, dust, etc. from entering the inside of the bearings, ensuring that the bearings operate in a clean environment. In addition, the selection of sealing materials is also crucial. They should have good aging resistance and chemical corrosion resistance to adapt to different medical environments and working conditions.

Cleaning and Sterilization

Cleanability:The structural design of the bearings should facilitate cleaning, avoiding complex shapes and hard – to – reach corners to prevent the accumulation of dirt and bacteria. For example, a smooth surface design can be adopted to reduce surface roughness, making it difficult for contaminants to adhere. At the same time, during the installation and maintenance of the bearings, strict cleaning procedures should be developed, and special cleaning tools and cleaning agents should be used to ensure the cleanliness of the bearing surface and interior. For some disassemblable bearings, they should be regularly disassembled and cleaned to remove internal impurities and wear particles.

Sterilization Compatibility:Medical equipment needs to be strictly sterilized before use, and the bearings must be able to withstand common sterilization methods. High – temperature and high – pressure steam sterilization is a common sterilization method. The bearing materials and structures need to maintain stable performance in a high – temperature and high – pressure environment and should not deform or crack. Although ethylene oxide sterilization causes less damage to the equipment, the bearing materials also need to have good tolerance to ethylene oxide and should not be affected in performance due to the absorption of ethylene oxide. Gamma – ray sterilization requires that the bearing materials have good radiation stability and should not change in performance under the action of radiation.

Quality Control and Inspection

Production Process Control:During the production process of bearings, strictly controlling various process parameters is the basis for ensuring product quality. From the melting and forging of raw materials to mechanical processing, heat treatment, and other links, parameters such as temperature, pressure, and processing speed need to be accurately controlled. For example, during the forging process, an appropriate forging ratio can make the internal structure of the material more compact, improving the strength and toughness of the bearings. In the heat treatment process, precisely controlling the heating temperature and cooling rate can enable the bearings to obtain the desired metallographic structure and hardness, thus ensuring the consistency and stability of their performance.

Stringent Inspection:Comprehensive inspection of bearings through various inspection methods is an important measure to ensure their reliability. Visual inspection can detect defects such as cracks and sand holes on the bearing surface. Dimensional accuracy measurement uses high – precision measuring tools, such as coordinate measuring machines, to accurately measure various dimensions of the bearings to ensure they meet the design requirements. Hardness testing can check whether the hardness of the bearing material is within the specified range to ensure its wear resistance and strength. Rotational performance testing uses special equipment to simulate the rotation of the bearings in actual operation and detect parameters such as rotational accuracy and friction torque. Only bearings that meet all the indicators can be used in medical equipment.

Reliability Design and Life Assessment

Redundancy Design:For some critical medical equipment, such as extracorporeal circulation equipment used in heart surgery, to ensure the safe operation of the equipment in case of bearing failure, a redundant bearing design can be adopted. That is, multiple bearings are installed to share the load. When one bearing fails, other bearings can temporarily replace it, buying time for equipment maintenance and replacement and avoiding endangering the patient’s life due to bearing failure and equipment shutdown.

Life Assessment:The service life of bearings in specific medical equipment is evaluated through theoretical calculations and actual simulation tests. Theoretical calculations are based on parameters such as the bearing load, rotation speed, and working temperature, and methods such as fatigue life theory are used to predict its life. The actual simulation test is to simulate the working environment of medical equipment in the laboratory and conduct long – term operation tests on the bearings, observing their wear, fatigue, and other conditions to more accurately evaluate their actual service life. According to the life assessment results, a reasonable maintenance and replacement plan is developed to ensure that the bearings always maintain reliable performance during the equipment operation.

The Price of Slewing Bearings for Medical Equipment

The price of slewing supports for medical equipment is affected by many factors. The material is the foundation. Slewing supports made of high – quality steel have high strength, good toughness, and excellent wear resistance, which can ensure the long – term stable operation of medical equipment, and their prices are relatively high. If ordinary materials are used, although the cost is reduced, the performance and durability may be compromised. The manufacturing process is also crucial. Advanced and precise processes can strictly control the dimensional accuracy and surface roughness. The slewing supports produced by such processes have better performance and naturally come at a higher price. While products produced by simple processes may have a price advantage, there may be potential problems in terms of quality and reliability.

Supplier of Slewing Bearings for Medical Equipment

LDB bearing is also outstanding in terms of service. The company has established a complete pre – sales, in – sales, and after – sales service system to provide customers with comprehensive and one – stop services. Before sales, a professional technical team will communicate in – depth with customers to understand their actual needs and provide customers with personalized product solutions. During sales, the production progress is strictly controlled in accordance with the production management system to ensure on – time product delivery, and the product quality is strictly inspected, with each processing step being tested.

The operating state of bearings affects the performance of equipment and production efficiency. It is crucial to select an appropriate fault diagnosis method, and the selection of the diagnosis method also needs to be considered comprehensively.

What is the feature of Slew bearings?

Slew bearings are key components in mechanical transmission and have many distinct characteristics. Structurally, rolling slew bearings generally consist of an inner ring, an outer ring, rolling elements, and a cage, with each part working in coordination; sliding slew bearings mainly include a slew bearing housing and a slew bearing bush. In terms of performance, they can effectively reduce the friction between moving parts and improve mechanical efficiency. They also have a high load – carrying capacity and can withstand radial and axial loads. Slew bearings are available in different accuracy grades to meet the diverse requirements of equipment, from common to high – precision ones. Moreover, slew bearings have good rotational stability, ensuring the stable operation of equipment, and are widely used in various mechanical fields such as automobiles, machine tools, and motors.

Determine Strategies Based on Equipment Characteristics

The fectures of the equipment itself are the fundamental basis for choosing a diagnosis method. Regarding speed and load, slew bearing failures in high – speed equipment can cause high – frequency vibrations. The vibration analysis method, with its ability to capture high – frequency signals, is an ideal choice for such equipment. For example, in a gas turbine, where the slew bearing rotates at an extremely high speed, high – sensitivity acceleration sensors installed at key positions can collect vibration signals in real – time. Through signal processing techniques such as the Fast Fourier Transform, the vibration spectrum can be analyzed to accurately identify slew bearing fault types, such as early wear of the balls and fatigue cracks in the raceways. For heavy – load equipment, like the hoist of a large – scale mining machine, which endures huge pressure for long periods, the slew bearings are prone to problems such as wear and plastic deformation due to overloading. In this case, the combined use of the temperature monitoring method and the oil analysis method can be very effective. Temperature monitoring can promptly detect slew bearing overheating caused by excessive load, while oil analysis can detect the concentration and composition of metal particles in the oil due to wear, enabling the determination of the wear degree and location of the slew bearing.

Make Choices According to the Working Environment

The working environment significantly affects the applicability of diagnosis methods. In high – temperature environments, such as the slew bearings of blast furnace fans in the metallurgical industry, the conventional oil analysis method may produce errors due to the impact of high temperature on the oil performance. In this case, the vibration analysis method and the temperature monitoring method based on infrared technology are more reliable. Infrared thermal imagers can measure the surface temperature of slew bearings from a distance and non – contact, quickly identifying areas with abnormal temperatures. In humid or corrosive environments, such as the slew bearings of chemical equipment, the slew bearings are prone to corrosion failures. Although the visual inspection method can directly observe surface corrosion signs, it is difficult to detect internal corrosion. However, the combination of the vibration analysis method and the ultrasonic testing method can effectively make up for this deficiency. Ultrasonic waves can penetrate the slew bearing material to detect internal micro – defects and the degree of corrosion.

Select Methods According to Fault Types

Different fault types require targeted diagnosis methods. For early – stage faults, the vibration analysis method and the acoustic detection method have unique advantages. Early – stage slew bearing wear, fatigue damage, and other faults can cause weak abnormal vibrations and sound signals during slew bearing operation. Through high – resolution vibration sensors and high – sensitivity acoustic sensors, combined with advanced signal processing algorithms, these subtle changes can be captured. For example, wavelet transform can be used to decompose the vibration signal to extract early – stage fault features and achieve early – warning of faults. The oil analysis method can also play a role in early – stage detection. By analyzing the number, shape, and composition of wear particles in the oil, the wear trend of the slew bearing can be detected in advance.

The diagnosis of sudden faults relies more on methods that can respond quickly. When sudden faults such as part breakage or jamming occur in a slew bearing, the vibration analysis method will detect a sharp increase in the vibration amplitude and a mutation in the frequency components. At the same time, the temperature monitoring method can also detect an instant increase in temperature. These abnormal signals can be quickly alerted through an automated monitoring system, enabling operators to take timely measures to prevent the accident from escalating.

Make Decisions by Weighing Cost – Benefit

Cost – benefit is an important factor that enterprises must consider when choosing a diagnosis method. From the perspective of initial investment, vibration analysis equipment, high – precision oil testing instruments, etc., are expensive. For small and medium – sized enterprises with limited funds or some application scenarios with low requirements for equipment accuracy, such as the ventilation equipment in small factories, it is more practical to use the cost – effective visual inspection method and simple temperature monitoring devices. Considering maintenance costs, the oil analysis method requires regular sampling, sending for inspection, and consuming chemical reagents, which can be costly in the long run; the sensors used in the vibration analysis method need to be calibrated and maintained regularly, also incurring certain costs. Therefore, enterprises need to comprehensively consider the importance of the equipment, the potential losses caused by faults, and the maintenance budget to weigh and choose a suitable diagnosis method.

Arrange Reasonably by Referring to Personnel Skills

The skill level of personnel is also a factor that cannot be ignored. Diagnosis methods such as vibration analysis and oil analysis require professional technicians to collect, analyze, and interpret data. For enterprises lacking professional talents, complex diagnosis methods may not be effectively utilized. In this case, it is more appropriate to choose simple – to – operate and easy – to – understand methods such as visual inspection and temperature monitoring. At the same time, enterprises can improve personnel skills through internal training and external further education to gradually introduce more advanced diagnosis methods.

Select Means by Matching Diagnosis Accuracy

The requirement for diagnosis accuracy determines the level of method selection. For equipment with extremely high accuracy requirements, such as aero – engines and lithography machines, a single diagnosis method is difficult to meet the needs. It is necessary to comprehensively use multiple high – precision methods. The vibration analysis method combined with the oil analysis method, supplemented by non – destructive testing techniques such as X – ray flaw detection and ultrasonic flaw detection, can comprehensively monitor the slew bearing status from multiple dimensions to ensure the safe and reliable operation of the equipment. For general industrial equipment, such as ordinary motors and reducers, under the premise of meeting basic production requirements, relatively simple diagnosis methods can be used to ensure the diagnosis effect while reducing costs.

Determine the Method by Combining Real – Time Monitoring

The need for real – time monitoring varies according to the operating characteristics of the equipment. For key equipment that operates continuously and does not allow downtime, such as the slew bearing of the reactor agitator in a large – scale petrochemical plant, real – time online monitoring methods must be adopted, such as the vibration monitoring system based on the Internet of Things and the real – time oil monitoring system, to ensure that potential fault hazards can be detected in a timely manner. For intermittent – operation equipment, such as tower cranes on construction sites, regular inspections and detections can be carried out. Visual inspections, vibration detections, and oil analyses can be performed during equipment downtime intervals to rationally allocate monitoring resources and improve monitoring efficiency.

The accessibility of the equipment also affects the implementation of the diagnosis method. For slew bearings that are easily accessible, such as the sliding slew bearings on machine tool guides, simple methods such as visual inspection and manually feeling the temperature can be directly used for daily inspections. For slew bearings installed in enclosed spaces, at heights, or in dangerous areas, such as the main pump slew bearings of nuclear power plants, non – contact and remote – operation diagnosis methods are required. For example, robots equipped with detection equipment can be used for vibration detection, and remote infrared monitoring systems can be used for temperature monitoring to ensure the safe and efficient progress of the diagnosis work.

Choosing a suitable slew bearing fault diagnosis method for a specific application is a process of comprehensively considering multiple factors. Enterprises need to weigh the pros and cons based on factors such as equipment characteristics, fault types, cost – benefit, personnel skills, diagnosis accuracy, real – time monitoring requirements, and equipment accessibility, and make scientific decisions. When necessary, a comprehensive diagnosis strategy combining multiple methods can be adopted to achieve accurate diagnosis and effective prevention of slew bearing faults, ensuring the stable operation of equipment and enhancing the production efficiency and competitiveness of enterprises.

The Price of Slew bearings

The price of slew bearings is affected by many factors. Firstly, it is the type. Deep – groove ball slew bearings have a simple structure and a large usage volume, so their prices are affordable; tapered roller slew bearings can withstand combined loads, and their manufacturing process is complex, resulting in relatively high prices. The size specification is also crucial. Large – sized slew bearings require more materials and are difficult to manufacture. For example, large – sized slew bearings used in wind power equipment are expensive; the opposite is true for small – sized slew bearings. In addition, the higher the accuracy grade, the more stringent the processing requirements, and the more expensive the price.

Supplier of Slew bearing

LDB bearing will continue to adhere to the corporate vision of “meticulous manufacturing, serving the world”, continuously increase investment in research and development, improve product quality and technical levels, expand market areas, strengthen international cooperation, and strive towards the goal of becoming a world – class slew bearing manufacturer. It is believed that with the joint efforts of all employees of LDB slew bearing, this enterprise, which carries numerous honors and dreams, will surely write an even more glorious chapter in the industrial slew bearing field and make greater contributions to the development of the global industry.