Applications of Hybrid Bearings

Hybrid bearings extend performance and life, having more useful features than standard bearings. Hybrid bearings have steel rings typically made from AISI52100, 440C, or Cronodur. Hybrid bearings usually have a nonmetallic retainer such as polyamide and ceramic rolling elements. The combination of steel rings, polyamide retainers, and ceramic balls is free of maintenance, has reduced friction, and is lighter in weight than standard bearings. Hybrid bearings are available as ball bearings and cylindrical roller bearings. Many times, they can be customized for most applications, and as such are used in a wide range of applications.

Hybrid bearings are used as insulating bearings. As you may know, bearings operating in environments near stray electric currents can cause havoc with bearings. In applications like electric motors and generators, the use of hybrid bearings has proved to be an easy and reliable solution. When Hybrid bearings are used in applications like variable speed drive electric motors and wind turbine generators, the ceramic material insulates the bearing.

SKF’s new cage design for hybrid deep groove ball bearings combines innovative design features with a high-performance polymer material.

A key design feature of hybrid bearings using ceramic balls is to reduce friction. When friction is reduced in the bearing, less rolling resistance results in reduced electrical draw. Ceramic balls have smaller contact ellipses resulting in less energy losses.

Industry tests have shown that friction torque is up to 8% lower using hybrid bearings. When using hybrid bearings, little to no lubrication is used in helping to further reduce internal friction. 

It is possible to reduce friction by as much as 50% when applying all the features and optimizing the application.

Advanced Hybrid Bearings 

Advanced hybrid bearings are an innovative solution in bearing technology that combines the strengths of both steel and ceramic components to meet the demanding needs of various high-performance applications. Typically featuring steel rings and ceramic balls – often made of silicon nitride – these bearings offer several advantages over traditional all-steel bearings, making them ideal for environments that require superior performance.

One of the outstanding benefits of advanced hybrid bearings is their ability to operate at high speeds with reduced friction. The lighter ceramic balls generate less centrifugal force during rotation, which minimizes frictional heat and wear. This feature allows the bearings to maintain performance under extreme conditions, making them particularly suitable for high-speed machinery, electric motors, and precision instruments. In addition, their excellent wear and corrosion resistance make them ideal for harsh environments, as ceramic balls are less susceptible to damage from abrasive particles and chemical exposure.

Another significant benefit of advanced hybrid bearings is their inherent electrical insulation properties. The ceramic balls act as a barrier to prevent electrical currents from passing through the bearings, which is especially important in applications such as electric motors and generators where electrical discharge can cause premature bearing failure. This insulating capability not only extends the life of the bearings but also protects surrounding components, increasing overall system reliability.

Advanced hybrid bearings applications:

In electric motors and generators, their low friction and electrical insulation properties make them essential for improving efficiency and reducing wear, particularly in electric vehicles and wind turbines.

The aerospace industry relies on these bearings in aircraft engines and auxiliary power units for their ability to withstand extreme speeds, temperatures, and contaminants, while their lightweight design helps optimize performance.

Machine tools and precision equipment, such as CNC machines, benefit from the bearings’ low thermal expansion and high-speed capacity, ensuring precise and efficient operation.

Medical equipment, including MRI machines and dental drills, use advanced hybrid bearings for their non-magnetic properties and reliable high-speed performance, which are critical in sensitive medical environments.

Semiconductor manufacturing requires ultra-clean conditions and precise motion control, whereas hybrid bearings excel due to their resistance to corrosion, low particle generation, and high-speed operation.

Overall, advanced hybrid bearings provide a solution for applications that demand high performance, minimal maintenance, and adaptability to extreme conditions. Their unique combination of steel and ceramic components provides a balance of strength, and speed, making them an invaluable choice in a wide range of industries.

Ceramic Hybrid Bearings vs Steel Ball Bearings 

Ceramic hybrid bearings and steel ball bearings are two common types of bearings used across various industries. Each type offers distinct advantages and drawbacks, making them suitable for different applications based on specific performance criteria, environmental conditions, and operational requirements. This analysis provides a detailed comparison of these two types of bearings, focusing on aspects such as material properties, performance characteristics, durability, and suitability for different industrial applications.

Material composition 

Ceramic hybrid bearings consist of steel rings combined with ceramic balls, typically made from silicon nitride (Si3N4). The ceramic balls are significantly lighter, harder, and less dense compared to steel balls, which contributes to various performance enhancements. In contrast, steel ball bearings are entirely made from steel, including both the rings and the balls, which makes them heavier but generally less expensive.

Performance сharacteristics

Speed and friction:

Ceramic hybrid bearings offer superior high-speed performance due to the lighter ceramic balls, which generate lower centrifugal forces at high speeds. This results in reduced frictional heat and allows for operation at higher RPMs—typically up to 50% higher than steel ball bearings. For instance, ceramic hybrid bearings can operate at speeds exceeding 1.5 million DN (Diameter x RPM), while steel ball bearings are generally limited to around 1.0 million DN.

Load capacity:

Steel ball bearings generally have a higher static load capacity due to the homogeneous material composition, which uniformly distributes loads across the bearing. This makes them more suitable for applications involving heavy loads and low speeds. Conversely, the hybrid design may limit the static load capacity slightly due to differences in material properties between the balls and rings.

Wear and longevity:

Ceramic hybrid bearings exhibit lower wear rates due to the higher hardness of the ceramic balls (78-80 HRC compared to 58-65 HRC for steel). This results in a longer lifespan, particularly in conditions with inadequate lubrication or where contaminants are present. Ceramic bearings can last up to 5 times longer than steel bearings under certain conditions, especially in high-speed or corrosive environments.

Ceramic hybrid bearings are well-suited for high-speed, high-precision applications such as aerospace, electric motors, machine tools, and semiconductor manufacturing. Their ability to operate under extreme conditions with minimal maintenance makes them valuable in settings where reliability and long service life are critical. Steel ball bearings, while less specialized, are widely used in heavy machinery, automotive applications, and general-purpose machinery

Applications for Hybrid Bearings

Miniature hybrid ball bearings are commonly used at high speed in dental turbines, contra angle handpieces, and dental motors. These dental products reach speeds up to 500,000 rpm. Other ideal candidates for hybrid bearings are in Aviation, Aerospace, and Defense applications. The automotive industry, due to stricter emission directives, looks to increase motor efficiency. Turbochargers reach speeds of more than 250,000 rpm and can operate in temperatures from -40 to +320°C by applying hybrid bearings. In the machine tool industry, high-precision ABEC7 and ABEC9 hybrid angular contact bearings are being specified for high-speed machine tool spindles.

Ceramics was introduced in the 1960s by the aerospace industry. Ceramics having high heat resistance properties and being lightweight were a perfect solution. By the 1980s, ceramic was becoming widely used. Hybrid bearings are used in many other applications including railways, electric vehicles, traction motors, compressors, pumps, vacuum pumps, and fluid machinery.

Silicon Nitride (ceramic) has properties that are much higher than steel. Interestingly, silicon nitride has double the hardness of AISI 52100 steel. With its coefficient of thermal elongation far lower than steel, it makes silicon nitride more accurate when calculating internal clearance values in low temperatures.

Speed ratings for hybrid bearings increase by around 10% merely by changing materials to silicon nitride versus AISI steel. In some industry tests, the lifespan of the lubricant in a hybrid deep groove ball bearing was twice to five times that of standard steel and cylindrical bearings. The lubricant lasts longer because the heat generation in the hybrid bearing is so much lower than in standard steel bearings.

There are a multitude of benefits to using hybrid bearings, and each application can be improved significantly with proper design and consideration of the operating environment. If you would like more information on hybrid bearings or full ceramic bearings, please contact Pacific International Bearing Sales Inc.