NACHI bearings for demanding industrial applications

Bearings are among the key machine elements in industrial drives, electric motors, pumps, fans, conveyor systems, gearboxes and other equipment where rotation must be reliable, quiet and dimensionally stable. When selecting a bearing, the basic bearing dimension is not the only important factor. Internal design, material, lubricant, sealing, load capacity, permissible rotational speed and resistance under load are also essential.

NACHI EXQ spherical roller bearings

 

Spherical roller bearings are used where the bearing position carries higher radial loads and must also accommodate axial forces and minor angular misalignment between the shaft and housing. Such conditions are typical of industrial gearboxes, conveyor equipment, heavy-duty drives, vibrating equipment, fans, crushers and other process equipment.

The NACHI EXQ series is developed for higher load capacity, lower temperature rise during rotation and longer service life. The special feature of this series is its optimized internal design, which affects roller guidance, load distribution and thermal conditions inside the bearing.

 

Number 1 in the world!

--> With the largest roller diameter, length and number of rollers, together with an optimized roller and raceway profile, NACHI achieves the highest load ratings in the world.
--> NACHI also offers a vibration-resistant version with a reinforced cage and improved corrosion protection.

What does the EXQ design provide?

In the EXQ design, the raceway profile and roller contact surface are optimized. This improves the transmission of axial loads and helps the bearing operate more effectively in conditions where an axial component is present in addition to the radial force.

A floating guide ring ensures controlled roller movement during rotation. This reduces internal losses, limits heat generation and contributes to a higher permissible rotational speed.

The bearings are made from high-purity steel, which reduces the risk of material damage and extends service life when the bearing is correctly selected, installed and lubricated.

Standard heat stabilization enables operation at temperatures up to 200 °C, which is important in industrial drives where elevated temperatures occur due to load, speed or the surrounding environment.

 

Performance comparison tables for the EX and EXQ series

EXQ-V for vibrating applications

For equipment exposed to shock and vibration loads, the EXQ-V version is available. This version has a special surface heat treatment on the steel cage, which improves cage resistance under impact loads.

EXQ-V also has special requirements regarding dimensional accuracy and radial internal clearance, so it is used in vibrating applications where the standard bearing design is not always the appropriate choice.

Typical areas of use for the EXQ-V design include:

• vibrating screens
• screening machines
• crushers
• industrial equipment with impact loads
• machines with uneven loads during operation

Main advantages of NACHI EXQ

• higher axial load capacity due to the optimized internal design
• lower temperature rise under load and at higher rotational speeds
• higher permissible rotational speed compared with the classic EX design
• longer service life thanks to high-purity steel
• standard heat stabilization for use up to 200 °C
• EXQ-V design for vibration and impact loads
• versions with cylindrical or tapered bore
• versions with lubrication holes and W33 groove for lubricant supply

When to choose EXQ spherical roller bearings?

The EXQ design is suitable for bearing positions where higher radial loads, additional axial forces, higher rotational speeds or increased bearing heat are present. It is particularly useful in industrial drives where a combination of load capacity, durability and resistance to demanding operating conditions is important.

In applications with pronounced vibration or impact loads, the use of the EXQ-V design should be checked, as it has a structural adaptation for such conditions.

 

NACHI EXQ OFFER

 

NACHI Quest deep groove ball bearings

Deep groove ball bearings are among the most commonly used bearings in industry. They are used in electric motors, pumps, fans, smaller gearboxes, conveyor rollers, tools, household appliances and many other rotating assemblies.

The NACHI Quest design is developed for applications where higher speeds, quiet operation, lower rotational resistance, and the temperature resistance of seals and grease are important. Special emphasis is placed on steel cleanliness, improved grease and seals with higher temperature resistance.

 

Better seals for higher temperatures

With conventional rubber seals, elevated temperature can cause the sealing lip to harden. This results in poorer sealing and a higher risk of dust, moisture or other contaminants entering the inside of the bearing.

NACHI Quest uses more heat-resistant nitrile rubber seals. These seals retain their sealing function better at elevated temperatures, so contamination ingress after temperature exposure is lower than with a conventional seal design.

Different closure designs are available:

• NSE9 – contact rubber seal for better protection against contaminants
• NKE9 – non-contact rubber seal for lower rotational resistance
• ZZE – metal shield for applications where protection is important while maintaining high rotational speed

 

Display of test results on 6206-2NSE and 6206-2NSE9 bearings. The bearings were exposed to muddy water spray at a rotational speed of 1000 min⁻¹ in an intermittent test lasting 20 hours. The amount of dust in bearings with rubber seals was checked after prior exposure to a high temperature of 140 °C for 70 hours.

Main advantages of NACHI Quest

• high-purity steel for longer service life
• improved grease with longer durability at elevated temperatures
• more heat-resistant nitrile rubber seals
• reduced dust ingress after thermal exposure of the seal
• quiet operation and low rotational resistance
• versions with contact seals, non-contact seals or metal shields
• compliance with ELV and RoHS requirements
• free of hazardous substances such as hexavalent chromium

When to choose Quest ball bearings?

The Quest design is the right choice for applications where rotational speed, quieter operation, longer grease durability and more reliable protection of the bearing interior are important. It is especially effective in electric motors, fans, pumps and other devices where the bearing operates for long periods, often at elevated temperature.

The NSE9 contact seal is a good choice where there is more dust, moisture or contamination. The NKE9 non-contact seal is used at higher speeds and where lower rotational resistance is required. The ZZE metal shield is a common solution in applications that require protection against larger particles while a higher permissible speed is also important.

 

NACHI QUEST INQUIRY

 

EXQ or Quest – which type should you choose?

If the application requires high load capacity, the transmission of higher radial and axial forces, and resistance under demanding industrial conditions, the EXQ spherical roller bearing is a sensible choice. For vibration and impact loads, the EXQ-V design should also be checked.
If the focus is on rotational speed, quiet operation, low resistance and a sealed design with improved grease or sealing, the Quest deep groove ball bearing is the more suitable choice.
Both bearing types are developed for different tasks, so a direct comparison is not a question of a better or worse design, but of the correct choice according to load, speed, temperature, environment and the design of the bearing position.

Most common mistakes when selecting bearings

When selecting a bearing, problems often arise not because of bearing quality, but because of the wrong design choice or unsuitable operating conditions. The most common causes of premature damage are:

• wrong bearing type selected for the load
• unsuitable internal clearance
• too little or too much lubricant
• sealing unsuitable for the environment
• incorrect installation
• poor alignment of shaft and housing
• excessive temperature at the bearing position
• rotation without sufficient radial load in roller bearings

Related content

• NACHI EXQ PDF leaflet
• NACHI QUEST PDF leaflet
• Bosch Rexroth ball transfer units – a small element with a big role in moving loads
• Bearing failure: 4 most common causes and how to prevent them
• Schaeffler presents innovative solutions for the food and packaging industry
• NACHI bearing technology product range