Bearings used in Extreme Operating Conditions

PIB offers bearings for use in special environments including corrosive, clean, vacuum,  and high-temperature situations. Many bearings are required to have special properties, such as non-magnetic, insulating or extreme high-speed.

Standard bearings made from 52100 chrome bearing steel using typical lubrication such as oil and grease cannot be used effectively in many of these environments.

PIB offers a variety of manufacturers products each offering unique solutions. Special bearing material types include Cronoduir, corrosion-resistant stainless steel, ceramic, high-speed M50 steel, as well as bearings using solid lubricants like high-molecular fluorine and molybdenum disulfide coatings and other exotic custom materials.

JTEKT’s EXSEV series offers a variety of solutions for challenging extreme operating conditions for both radial and linear applications.  One example is what they call the Clean Pro Bearing for use in Clean Vacuum applications.

Clean Pro Bearing Series Long-Service-Life Type.This bearing has a fluoropolymer gel coating on its rolling surfaces as the lubricant.

Applications：

Semiconductor manufacturing equipment, Transfer systems, Lithography equipment, Vacuum motors, Vacuum equipment

PIB Sales understands the uniqute challenges facing engineers and focuses on providing solutions that go beyond just components. PIB  offers advanced bearing solutions for you to consider to solve difficult environments.

Understanding Extreme Operating Conditions

Each Environment can  present  unique demands on bearing design and material selection. These challenges often present themselves independently, but just as often occur in complex combinations, amplifying their problem solving impact. The potential for finding solutions has been improved dramatically over the recent years. Available material and design options from various manufacturers have significantly expanded beyond what conventional bearings can offer. Let’s explore.

High-temperature environments

The impact of high temperatures on bearings is a major failure issue.. As temperatures rise, conventional bearing steels lose their inherent hardness and tensile strength. Above 150°C, for instance, standard steel begins to exhibit diminished load-bearing capabilities and thermal expansion can introduce significant alignment issues within the bearing assembly. Moreover, traditional grease lubricants tend to degrade, leading to viscosity reduction and ultimately to premature failure. Certain applications can expose bearings to temperatures over 300°C, or even 800°C in highly specialized cases. This necessitates the use of advanced materials and very specialized solid lubricants, or synthetic liquid lubricants with very high flash points. It’s critical to recognize that this is not merely a structural issue; it’s equally crucial to manage the effects on the lubricant itself, which, if not carefully chosen, would simply carbonize and fail.

Cryogenic and low-temperature environments

Conversely, at the opposite end of the spectrum, extremely low temperatures, often below -100°C and potentially reaching liquid helium temperatures (-269°C), significantly alter material properties. Standard metallic structures become brittle and prone to fracture, while conventional lubricants become excessively viscous or can even solidify completely. This essentially eliminates the smooth rolling action required for effective bearing operation. Specialized low-temperature lubricants and solid lubricants are often required, along with materials with exceptional low-temperature stability.

Corrosive environments

Corrosion poses a significant, and often hidden, threat to bearings. Contact with corrosive agents, such as strong acids, alkalis, and even the ever-present chloride ions in saltwater, causes material degradation through surface corrosion and pitting. This unchecked degradation diminishes bearing life and leads to failure. Saltwater environments can be particularly aggressive to standard steels, requiring very specific material choices. Furthermore, the rate of corrosion is often greatly accelerated at higher temperatures.

Vacuum environments

Operating in vacuum conditions presents a unique set of challenges, especially concerning lubrication and potential contamination. Traditional bearing greases and oils can outgas in a vacuum, which can create contamination problems. Standard greases contain volatile compounds that can vaporize under vacuum, quickly resulting in a loss of lubrication, increased friction, and increased wear on bearing components. In vacuum systems as low as 10^-7 Torr standard lubricants are generally avoided, and solid lubricants with low outgassing characteristics, such as fluoropolymers, are typically used to maintain system performance.

High-speed operation

High-speed bearing applications require special attention to a range of issues, including heat generation due to friction, degradation of the lubricants at higher speeds, and the ever-present possibility of excessive vibration. Conventional bearings can rapidly reach and surpass their operational limits as speeds rise from 15,000 RPM to over 20,000 RPM. Centrifugal forces, acting on the rolling elements, place significant stress on the bearing’s components. Choosing bearings designed specifically to withstand these demands, which usually include specialized cages, unique material choices, and advanced lubrication, is essential. Ceramic or hybrid bearings with much lighter ceramic rolling elements are often used not only to reduce the heat generated but also to allow much higher operational speeds due to the lower inertial forces.

Magnetic and electric fields

In some highly specialized environments, bearings may be subjected to intense magnetic or electric fields. Standard steel bearings will become magnetized, potentially interfering with the functionality of sensitive surrounding equipment. In these cases, bearings manufactured from non-magnetic materials including  ceramics and specialized non-magnetic stainless steels are available.. In higher voltage applications, the bearing’s insulation properties will need to be considered.

Bearing Solutions for Specialized Environments

With an understanding of the diverse challenges that extreme operating environments present, it’s essential to explore the specialized bearing technologies designed to meet these demands. JTEKT’s EXSEV series and other specialized bearings are a great example. These are not merely modifications of standard bearings; they are purpose-built solutions, often incorporating advanced materials, innovative lubrication, and unique design features.

Clean Pro Bearings for Vacuum and Cleanroom Applications

In the pursuit of ever-smaller, more precise electronics, environments with strict cleanliness requirements have become vital. This is where the Clean Pro series steps in, offering specialized solutions for vacuum and cleanroom applications. The Clean Pro Bearing-RZ, for example, is designed for a long service life and achieves this through an innovative approach. Instead of traditional grease, it employs a fluoropolymer gel coating directly on the rolling surfaces, effectively providing long-lasting performance and also minimizing any risk of contamination. These are crucial design considerations in sensitive systems such as those used in semiconductor manufacturing, transfer mechanisms, and lithography equipment. The Clean Pro Bearing-RB offers the same lubrication method, but with an added ability to withstand temperatures up to 260°C, an ideal solution for equipment that may need to operate in both high-cleanliness and moderately high-temperature environments, such as LCD manufacturing and sputtering equipment. Stepping up the game, the New Clean Pro Bearing-PR takes the idea even further by ensuring that all of its components are lubricated with a fluoropolymer coating. This comprehensive approach guarantees that every single part is compatible with demanding clean and vacuum environments.

The EXSEV® Series: Tailored Solutions for Diverse Extremes: The EXSEV® line showcases the wide diversity of solutions that demanding applications require. Each bearing within this series is purpose-built to overcome very specific challenges, demonstrating a highly targeted engineering approach:

The EXSEV®-EX bearing is engineered for use in the most demanding clean and vacuum applications. It uses a specially formulated fluorinated EXSEV®-EX grease that is PFOA-free and therefore completely compliant with all existing environmental regulations. This is a critical consideration for equipment used in semiconductor and LCD manufacturing, as well as for transfer robots and vacuum pumps.

The EXSEV®-FA variant offers superior lubrication performance within vacuum environments. It achieves this by employing a solid fluoropolymer lubricant, in addition to a low-particle-emission fluorocarbon resin cage. The solid lubricant has extremely low outgassing properties, which minimizes system contamination. Its superior lubrication qualities also ensure reduced wear on the components.

The EXSEV®-XT is designed specifically to withstand high-temperature environments when also used in a vacuum. It utilizes a unique fluorinated grease that allows it to reliably operate up to 350°C. This impressive level of heat resistance makes it the perfect fit for semiconductor and LCD manufacturing equipment, robotic systems, and demanding vacuum pumps.

The EXSEV®-WS variant is designed to handle high heat resistance and also has exceptional load-carrying capacity. This is achieved through the use of a specially formulated heat-resistant tungsten disulfide, which is integrated directly into the separator. This unique solution offers impressive load capacity, but it’s typically recommended for horizontal-axis operation.

The EXSEV®-MG takes high-temperature and vacuum capabilities a step further by using silver ion plating directly on the stainless steel balls. This plating ensures superior lubrication in demanding vacuum conditions and under elevated temperatures, making it ideal for semiconductor manufacturing, LCD equipment, vacuum evaporators, and even certain medical and motor applications.

The EXSEV®-PN is designed for superior heat resistance, reaching up to 300°C, by using a solid lubricant that has molybdenum disulfide incorporated into the cage itself. This innovative solution combines high-temperature performance with a long-lasting design.

Finally, the EXSEV®-MO uses molybdenum disulfide baked directly onto the stainless-steel cage as the lubricant, offering reliable performance in 300°C environments. It’s a valuable option for systems that operate in semiconductor manufacturing, LCD production, vacuum evaporators, and rotary furnaces.

Corrosion Guard Pro Bearings:
When chemical exposure becomes a major concern, the Corrosion Guard Pro series provides a robust level of protection. The Corrosion Guard Pro Bearing-SC utilizes a silicon carbide ceramic material for its rolling elements, offering exceptional resistance against a variety of strong acids and alkalis. This, in combination with a fluorocarbon resin cage, provides unparalleled performance in chemically aggressive environments. Such capabilities are often required in equipment used for aluminum electrolytic capacitor manufacturing and other similar chemical processes. The Corrosion Guard Pro Bearing-ZO uses ceramic (zirconia) components for superior corrosion resistance. The PEEK resin cage provides additional chemical stability, as well as improved impact resistance. This combination of advanced materials makes it an excellent fit for high-performance film manufacturing and various cleaning applications.

The Corrosion Guard Pro Bearing-MD variant is engineered to withstand the highly corrosive conditions of saltwater and similar chemical environments. It uses specialized stainless steel with excellent corrosion resistance in combination with a fluoropolymer lubricant, which also makes it suitable for underwater use in food processing equipment, chemical facilities, and various other submersible applications.

The EXSEV®-SK serves as the baseline standard for stainless steel bearings within the EXSEV line. It uses a stainless-steel construction with a lithium grease containing EXSEV®-KHD, which is applied in sufficient quantities at the factory and is suitable for use in moderately corrosive environments for chemical equipment and various transfer systems.

Specialized High-Temperature and Vacuum Bearings:

For extremely high-temperature applications, Full Complement Ceramic Ball Bearings are made entirely from ceramic (silicon nitride) and are designed to operate at up to 800°C. These do not use any cage and are normally used in pairs to act as angular contact ball bearings, and are often used in high-temperature baking furnaces and similar industrial equipment. Non-Magnetic Hybrid Ceramic Bearings use non-magnetic stainless steel rings with silicon nitride ceramic balls. Fluoropolymer lubrication makes it usable in vacuum environments and it is perfect for sensitive equipment in semiconductor manufacturing, inspection, and other applications requiring extremely low magnetic interference. The Hybrid Ceramic Bearings use high carbon chromium steel for the inner and outer rings with silicon nitride ceramic balls. Using either oil or grease lubrication these are designed for use in high-speed or high-voltage applications. K Series Full Complement Hybrid Ceramic Ball Bearings are incredibly thin bearings made with martensitic stainless steel rings and silicon nitride balls. Using fluorinated EXSEV®-EX grease, these bearings are suitable for clean and vacuum applications and are often found in transfer robots or LCD manufacturing equipment.

Linear Motion Solutions for Extreme Environments

For environments requiring linear motion, there are specific bearing options:

• Linear Motion Ball Bearings are precision-made units that house rolling balls within a hardened external cylinder. This design enables precise linear motion in space-constrained environments.

• Linear Way Bearing Units are complete motion systems that use a slide unit with recirculating balls and allow smooth, high-precision linear movement on a track rail.

• Cross Roller Way Bearing Units are designed with two V-shaped raceway bases and cylindrical rollers, also allowing precise linear motion, but in a more compact design.

Finally, JTEKT also supplies Ceramic Balls made of silicon nitride. These provide remarkable resistance to wear, seizure, and corrosion, and are also resistant to ultra-high vacuums and can tolerate temperatures up to 800°C. They also possess excellent non-magnetic and insulating properties, making them a suitable choice for various applications such as tools, gauges, valves, and even high-grade bicycle components.

Choosing the Right Bearing for Extreme Conditions

The first and foremost consideration is the operating temperature. As we have discussed, high-temperature environments can degrade conventional lubricants and reduce the strength of standard steels. For high-heat applications, it is necessary to select bearings with specialized lubricants and heat-resistant materials such as ceramics, or steels specifically designed for high-temperature use. For example, if temperatures reach above 200°C or even 300°C, options such as the EXSEV®-XT or Full Complement Ceramic Ball Bearings should be carefully considered. At the other end of the spectrum, extremely low temperatures can also cause issues with lubricant viscosity and material brittleness, so bearings designed for cryogenic and low-temperature operation are essential in such cases.

The chemical environment is also a critical factor in bearing selection. If the bearing is likely to be exposed to corrosive agents, such as acids, alkalis, or even salt water, it’s vital to choose materials resistant to chemical attack. The Corrosion Guard Pro series is specifically designed for these environments, providing a range of solutions from silicon carbide ceramic bearings for strong chemicals to special stainless steel bearings for saltwater environments. If the environment has a combination of both high temperatures and corrosive agents, even more specific and unique materials and designs are required.

The rotational speed is another key consideration. Standard bearings are often inadequate for higher speeds. The use of lighter materials such as ceramic balls, more stable cage materials, and specialized lubrication may be necessary in very high-speed applications, as in the case of Hybrid Ceramic Bearings and similar types. The selection of a bearing optimized for high speed will not only ensure reliable operation but also minimize friction and heat buildup.

If the application involves vacuum or cleanroom conditions, it is vital to choose bearings designed to prevent outgassing and particle contamination. The Clean Pro series is specifically designed for this with its fluoropolymer lubricants, and the EXSEV®-FA provides a similar approach by using a low-particle-emission cage and solid lubricant. Choosing the wrong type of lubricant or cage can result in contamination of the system and should be carefully avoided.

Finally, the load and speed demands, and the specific application itself, also need to be considered. Understanding all the parameters involved allows for the best and most reliable choice to be made. Choosing between linear bearings, ceramic bearings, and other specialized designs is a complex process, requiring that every parameter is properly considered.

The selection of bearings for extreme conditions requires the right expertise. PIB Sales provides access to a wide variety of specialized bearings from JTEKT and other trusted manufacturers, along with the technical expertise needed to help you select the perfect solution for your specific needs. We don’t just offer parts; we provide solutions.

Are you facing challenges with bearings in demanding environments? Contact PIB Sales today. Our experienced team will assist you in selecting the optimal bearings that will guarantee reliable and long-lasting performance for your critical applications. Let us help you navigate the complexities and ensure that you have the perfect bearing solution.