Bearings play a crucial role in reducing friction between moving parts in a wide range of mechanical systems. By supporting and locating rotating shafts, bearings enable the smooth and efficient operation of machinery in industries such as manufacturing, agriculture, aerospace, and more. One common type of bearing used in industrial applications is the mounted ball bearing. In this article, we will examine what sets mounted ball bearings apart from other bearing types, their design and construction, key advantages, applications, selection considerations, and proper maintenance procedures. The aim is to provide readers with a comprehensive understanding of mounted ball bearings and how their unique characteristics make them suitable for supporting rotating shafts across various demanding mechanical systems.
Mounted ball bearings, sometimes referred to as flanged housed units, are a type of rolling element bearing that use balls as the rolling and load carrying elements. They consist of an inner and outer race which contain the balls, with the bearing assembled into a housing or mounting unit for easier installation and removal. The main components include the inner ring, outer ring, ball complement, cage or retainer, seals, mounting unit, and lubricant. Mounted ball bearings are versatile, compact, and can support both radial and moderate axial loads. They are ideal for applications that require frequent maintenance, as the housing allows the entire bearing assembly to be removed and installed as a singular unit. Compared to other bearings, mounted ball bearings offer high stiffness and speed capability combined with low-friction operation.
There are several major categories of bearings, including ball bearings, roller bearings, plain bearings, magnetic bearings, and air bearings. Within these broader categories exist different types suited to specific applications.
Roller bearings use cylindrical rollers between the inner and outer races to handle heavy radial loads and some axial loads. Variants include tapered, spherical, cylindrical, and needle roller bearings. Ball bearings like mounted units use spherical balls as the rolling elements and are optimal for applications with high speeds or that require low friction. Plain bearings involve sliding contact between the bearing and journal surface with a lubricant like oil or grease between them. They are simple in design but have higher friction than rolling element bearings. Magnetic bearings utilize magnetic levitation and require no lubrication, while air bearings use compressed air for low friction load support.
While sharing some similarities, mounted ball bearings differ from these other types primarily in their compact, self-contained design with a built-in housing and ease of maintenance. The ball complement provides low-friction operation not achievable with plain bearings, and the split-housing design enables quick installation compared to loose ball bearings.
The design of mounted ball bearings focuses on optimal internal geometry to ensure smooth rolling motion, strength under load, and long service life. Important design elements include the ball complement, ball size, contact angle, raceway curvatures, and cage design. Constructing the rings, balls, and other components from hardened or heat-treated steel alloys enhances durability.
Mounted ball bearings consist of two matched steel rings forming the inner and outer raceway, spherical balls that roll between the raceways, and a ball cage or retainer that maintains the ball spacing. Seals on each side help retain lubricant and exclude contaminants. The bearing assembly fits inside a solid housing, usually of cast iron or steel, which has attachment points for mounting onto a machine shaft or component. Common types of mounted housings include flanged units, take-up units, and cartridge units. The housing style depends on the application and how the bearing needs to be positioned and fastened.
Proper internal design paired with sturdy housing constructions enables mounted ball bearings to support demanding mechanical loads over thousands of hours of reliable operation. Careful material selection, manufacturing precision, and quality control testing also contribute to consistent performance.
There are several notable advantages that mounted ball bearings offer over plain bearings and other rolling element bearings:
- Handle moderate radial and axial loads due to ball contact angles.
- High limits on maximum speed capabilities, up to DN values of 500,000 in some cases.
- Lower friction compared to sliding contact bearings, saving energy.
- Compact, space-saving design with self-contained housing.
- Convenient to install, service, and replace as a single intact unit.
- Versatile housing designs to accommodate different positioning and attachment methods.
- Withstand misalignment and shock loading better than other sensitive bearings.
- Generate minimal noise during operation.
- Offer long service life with proper lubrication and maintenance.
- Readily available in a wide range of sizes, materials, load capacities, and accuracy grades.
The combination of smooth rolling motion, compact size, shaft misalignment tolerance, and convenient maintenance afforded by the split housing makes mounted ball bearings suitable for many demanding industrial applications.
Mounted ball bearings serve critical load support functions across a diverse range of machinery. Some common applications include:
- Electric motors - Support rotor shafts up to high speeds with low friction.
- Gearboxes - Handle input, output, and intermediate shafts under radial and axial loads.
- Conveyor systems - Enable rollers to spin freely in manufacturing and materials handling systems.
- Pumps & compressors - Withstand high speeds and radial/axial loads from impellers and rotors.
- Machine tools - Provide precision support for spindle shafts in lathes, mills, grinders etc.
- Robotics - Enable joint rotation and arm movements in production automation.
- Fans & blowers - Support fan shafts up to high speeds with low power loss.
- Agriculture equipment - Withstand shock loads and contaminants in harsh operating environments.
- Automotive drivelines - Support transmission shafts and differentials.
- Household appliances - Provide quiet, low-friction operation of motors and shafts.
In these and many other industrial and commercial applications, mounted ball bearings play a pivotal role in keeping the machines running reliably and efficiently. The bearings smoothly support the transmitting shafts and high-speed spindles that drive modern production.
Selecting the optimal bearing for an application depends on assessing operating conditions and load requirements. Important factors to consider include:
- Load capacity - Calculate radial, axial, and moment loads to choose appropriate load rating.
- Shaft size - Ensure proper fit between inner ring bore and shaft dimensions.
- Speeds and speeds - Select suitable dynamic and static load ratings for operating rpm.
- Operating temperatures - Check max and min temperatures fall within bearing capability.
- Alignment and positioning - Consider housing design and attachment method.
- Lubricant compatibility - Ensure seals and lubricant suit operating environment.
- Environmental conditions - Assess moisture, contaminants, vibration etc.
- Cost factors - Weigh initial cost vs. service life, maintenance, replacements.
- Industry standards - Review specifications and compliance requirements.
Consulting bearing manufacturer catalogs, online tools, and industry experts can help optimize mounted ball bearing selection for specific requirements, and avoid under or over-engineering.
To achieve their designed service life, mounted ball bearings require proper maintenance and re-lubrication at recommended intervals. Typical maintenance tasks include:
- Visual inspections - Check for external damage, wear, corrosion, leaks.
- Cleaning - Remove contaminants and old lubricant from races, balls, cage.
- Lubricating - Re-grease with sufficient amounts of fresh, compatible lubricant.
- Checking clearances - Inspect for proper internal clearances during maintenance.
- Testing and replacing seals - Ensure seals are intact to keep lubricant in and contaminants out.
- Adhering to service schedules - Maintain as per Original Equipment Manufacturer guidelines.
Storing spare mounted ball bearings in a clean, temperature controlled environment helps prevent deterioration. Partnering with bearing specialists and using condition monitoring tools can also optimize maintenance practices. With proper installation, lubrication, and care, mounted ball bearings provide reliable service for many years before needing replacement.
Mounted ball bearings are an invaluable component enabling rotating parts to operate smoothly across a vast range of industrial machinery. Their compact, versatile design with integrated housing provides convenient installation and maintenance compared to loose ball bearings. Mounted ball bearings support both radial and axial loads due to the spherical ball contact angle. They provide low-friction operation at high speeds, while tolerating misalignment and shock loading well. With careful selection and proper maintenance, mounted ball bearings serve reliably for thousands of hours in demanding conditions. Their unique advantages make mounted ball bearings a popular choice for supporting shafts and spindles in electric motors, gearboxes, conveyors, machine tools, and many other rotating machinery applications.
At Deyuan Smart Technology, we take great pride in the recognition our product quality and services have garnered from customers in the industry. We strive to provide exceptional products and services that meet and exceed customer expectations. You can trust us as your reliable partner in the pillow blocks industry. For further inquiries or to discuss your specific requirements, please contact kzhang@ldk-bearings.com or call +86-592-580 7618. We look forward to the opportunity to work with you.
References
Hamrock, B.J., Schmid, S.R., Jacobson, B. (2004). Fundamentals of Machine Elements. New York: McGraw-Hill.
Bhattacharya, A. (2014). Theory of Machines and Mechanisms. Oxford University Press.
SKF Group. (2021). Rolling Bearings.
