22318CA Self-Aligning Roller Bearing With Brass Cage For Heavy Machinery
In the intricate landscape of mechanical engineering, the 22318CA bearing stands as a testament to precision engineering and robust performance. Engineered to meet the exacting demands of a diverse array of industrial applications, this comprehensive product introduction will delve into the design intricacies, performance capabilities, material composition, application scenarios, and maintenance requisites of the 22318CA bearing, providing a holistic understanding of its pivotal role in modern machinery.
I. Design and Structure
Inner Ring and Outer Ring
The inner ring of the 22318CA bearing features a precisely machined double-row raceway, meticulously crafted to interface seamlessly with a shaft diameter of 90mm. This exacting fit not only ensures efficient force transfer post-installation but also minimizes the risk of slippage, optimizing mechanical performance. The outer ring, distinguished by its spherical raceway, confers upon the bearing its self-aligning prowess. This unique design element enables the bearing to adeptly accommodate misalignments between the shaft and the bearing housing, typically within an angular range of 1° - 2.5°. By mitigating misalignment-induced stresses, the bearing's operational lifespan and reliability are significantly enhanced.
With an outer diameter of 190mm and a width of 64mm, the 22318CA bearing strikes a harmonious balance between load-bearing capacity and spatial constraints. The outer ring's wall thickness has been strategically augmented, bolstering its resistance to impact forces and providing a more stable foundation for the raceway. This design choice renders the 22318CA bearing particularly well-suited for applications involving extended exposure to cyclic loading.
Rolling Elements and Cage
At the heart of the 22318CA bearing lies a double-row array of barrel-shaped rollers. These rollers, characterized by their curved profile, interact synergistically with the outer ring's spherical raceway, enabling the bearing to deftly handle both radial and bidirectional axial loads. Constructed from high-grade bearing steel, the rollers undergo a rigorous precision grinding process, culminating in a surface roughness of less than Ra0.1μm. This ultra-smooth finish is instrumental in reducing friction during rolling, thereby enhancing the bearing's energy efficiency and operational smoothness.
The "CA" suffix in the bearing designation denotes a brass cage with ribs. This cage design plays a pivotal role in maintaining the orderly arrangement of the rollers. Employing a segmented design, the cage ensures that the rollers are evenly spaced, providing each with ample room for unrestricted rotation. During high-speed operation, the cage also functions as a guiding mechanism, steering the rollers along their intended paths and preventing collisions that could otherwise precipitate premature wear. The brass material of the cage offers excellent thermal conductivity and mechanical strength, making it well-suited for medium to high-speed applications with heavy loads. It can effectively dissipate heat generated during operation and maintain structural integrity up to temperatures of 150°C.
Sealing Structure (Optional)
Certain variants of the 22318CA bearing are equipped with either contact or non-contact seals. The contact seal, fashioned from nitrile rubber, forms a tight seal with the inner ring, effectively repelling dust and moisture. This makes it an ideal choice for applications in dusty or humid environments, where protection against contaminants is of paramount importance. In contrast, the non-contact seal, featuring a labyrinth design, minimizes friction, rendering it more suitable for high-speed applications. This seal can accommodate rotational speeds of up to 3000rpm, ensuring smooth operation even under demanding conditions.
II. Key Parameters
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Parameter
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Value
|
|
Inner Diameter (d)
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90mm
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|
Outer Diameter (D)
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190mm
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Width (B)
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64mm
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III. Performance Advantages
Exceptional Load-Carrying Capacity
The 22318CA bearing's double-row roller design, combined with an optimized contact angle, endows it with an impressive basic dynamic load rating of 450kN and a static load rating of 610kN. This robust load-bearing capacity enables the bearing to effortlessly shoulder the substantial loads encountered in heavy machinery applications. Whether it's the intense impact forces in mining crushers or the high-pressure rolls in metallurgical mills, the 22318CA bearing demonstrates remarkable resilience, withstanding continuous heavy loading without succumbing to fatigue failure.
Superior Self-Aligning Capability
The seamless interaction between the outer ring's spherical raceway and the barrel-shaped rollers equips the 22318CA bearing with an outstanding self-aligning ability. This feature is particularly valuable in long-shaft applications, such as those found in paper machine press rolls and wind turbine main shafts. By automatically compensating for shaft deflection or installation misalignments, the bearing effectively reduces edge stresses, resulting in a service life extension of over 30%. This not only enhances the reliability of the equipment but also minimizes maintenance requirements and associated costs.
Robust Wear Resistance and Temperature Stability
Constructed from high-carbon chromium bearing steel (SUJ2), the bearing rings and rollers are heat-treated to achieve a hardness of HRC60 - 65. Additionally, the surface is phosphated to further enhance wear resistance. The bearing exhibits excellent dimensional stability and mechanical integrity within the temperature range of -40°C to 120°C. For applications necessitating operation at higher temperatures, specially heat-treated variants are available, capable of withstanding temperatures exceeding 200°C. This renders the 22318CA bearing suitable for a wide gamut of industrial applications, including those in high-temperature environments such as foundries and power plants.
Low Friction and Vibration Damping
The precision-machined raceways and rollers of the 22318CA bearing contribute to a remarkably low friction coefficient, as low as 0.0015. This not only reduces energy consumption but also enhances the bearing's overall efficiency. Moreover, the double-row symmetrical design ensures uniform load distribution, resulting in a vibration velocity level that can be effectively controlled below 65dB during operation. This makes the bearing an ideal choice for applications where precision and smooth operation are critical, such as in machine tool spindles and high-precision manufacturing equipment.
IV. Material Quality
Material of Rings and Rollers
The core material of the 22318CA bearing is high-purity bearing steel (GCr15SiMn), processed using a vacuum degassing technique to eliminate internal pores and inclusions. This results in a material with exceptional density and mechanical properties. The rollers undergo a series of manufacturing processes, including cold heading forming and high-temperature tempering, which contribute to a uniform internal structure. The impact toughness of the material exceeds 12J/cm², significantly enhancing the bearing's resistance to fatigue and ensuring long-term reliability under demanding operating conditions.
Cage Material
As mentioned earlier, the "CA" suffix indicates a brass cage with ribs. Brass (H62) is renowned for its excellent thermal conductivity and mechanical strength. It can effectively dissipate heat generated during the bearing's operation, which is crucial for maintaining stable performance, especially in applications where high speeds and heavy loads generate substantial heat. The mechanical strength of the brass cage allows it to withstand the forces exerted on it during the bearing's operation, ensuring the proper alignment and movement of the rollers. This makes the brass cage a reliable choice for medium to high-speed applications with heavy loads.
V. Application Fields
Heavy Industrial Machinery
In the mining sector, the 22318CA bearing is deployed in the eccentric shafts of jaw crushers, where it must endure the massive crushing forces and frequent impact loads associated with the rock-breaking process. In the metallurgical industry, it provides essential support for the work rolls in rolling mills, withstanding the combined challenges of high temperatures and intense rolling pressures.
Construction Machinery
The output shafts of gearboxes and slewing bearing components in loaders and excavators often rely on the 22318CA bearing. Its ability to resist eccentric loads ensures stable power transmission, even when the machinery is operating on uneven terrain. In crane winches, the bearing's high load-carrying capacity is crucial for ensuring the safe and reliable lifting of heavy loads.
Energy Equipment
Wind turbine main shaft systems benefit significantly from the self-aligning capabilities of the 22318CA bearing. As the blades rotate, they generate forces that can cause shaft deflection, which the bearing can effectively compensate for while simultaneously bearing the radial and axial loads converted from wind energy. In hydropower stations, the bearing's wear resistance makes it suitable for use in water turbine main shafts, where it must operate in submerged or humid conditions for extended periods.
Papermaking and Textile Machinery
In large paper machines, the 22318CA bearing is employed in calender rolls and drying roll groups. Its low vibration characteristics are essential for ensuring uniform paper pressing and drying, thereby maintaining product quality. In the textile industry, dyeing and finishing equipment utilize the bearing's high-temperature and corrosion resistance to operate smoothly in humid and hot environments, ensuring continuous and reliable production.
VI. Installation and Maintenance
During installation, it is imperative to use specialized tools, such as hydraulic nuts, to ensure that the inner ring is subjected to uniform force. This precautionary measure helps prevent deformation caused by improper installation methods, such as hammering. For models with tapered inner rings, the clearance can be precisely adjusted using a lock nut, with the recommended working clearance range typically falling between 0.12 - 0.25mm.
In terms of lubrication, for grease-lubricated applications, extreme pressure lithium-based grease (NLGI Grade 2) is recommended. The filling amount should be carefully controlled, typically ranging from 1/3 to 1/2 of the bearing's internal space. For high-speed applications, oil lubrication is more suitable, with ISO VG 46 or 68 lubricating oil being commonly used. When employing forced lubrication, the oil pressure should be maintained within the range of 0.1 - 0.3MPa.
Regular maintenance is crucial for ensuring the bearing's optimal performance and longevity. This includes monitoring the bearing temperature, which should generally remain below 70°C, as well as checking for abnormal vibration and noise. Any signs of abnormality should be promptly addressed, often necessitating the replacement of the bearing. During disassembly, a puller should be used to avoid causing damage to the journal and bearing housing hole, ensuring that the surrounding components remain in good condition for future use.
VII. Conclusion
The 22318CA bearing represents a paragon of engineering design, offering a harmonious blend of high-strength construction, exceptional self-aligning capabilities, and broad adaptability to diverse operating conditions. Whether confronted with extreme loads, shaft misalignments, or challenging environmental factors, this bearing consistently delivers stable performance. Its pivotal role in enabling the efficient operation of industrial machinery underscores its importance as an indispensable component in modern mechanical engineering, driving progress across a wide spectrum of industries.
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