Rolling Bearing Designations – A Complete Guide

Rolling bearings are essential components in various machines, enabling smooth operation and minimizing friction. Bearing designations serve as detailed informational codes that specify the bearing's construction, materials, and technical parameters. This guide provides an in-depth explanation of prefixes, suffixes, and codes used by leading manufacturers. Learn how to interpret these symbols correctly to select the optimal bearing for your needs.

Prefixes – Identifying Structural Features

Prefixes appear before the basic number and indicate unique features of the bearings, such as material, additional functionalities, or specific dimensions. Although not commonly used, they play a crucial role in identifying special bearing models.

Examples of common prefixes:

• F – Outer ring with flange.
• SS/S – Stainless steel.
• EX, E, EC – Increased load capacity due to special construction.

Basic Number – Bearing Type and Dimensions

The basic number consists of two main parts:

1. The first digit specifies the bearing type:

   • 0 – Double-row angular contact bearing.
   • 6 – Single-row deep groove ball bearing.
   • N – Cylindrical roller bearing.
   • C – CARB toroidal roller bearing.

2. The second part provides dimensional information:

   • The first digit describes the width (for radial bearings) or height (for thrust bearings).
   • The second digit indicates the outer diameter – higher values mean larger dimensions.

Example: 6205

• A single-row deep groove ball bearing with a bore diameter of 25 mm (2 x 5).

Suffixes – Technical Parameters

Suffixes in bearing designations highlight additional features, such as materials, clearance, or precision:

1. Cage material:

   • J, W – Steel cage.
   • M, MA, MB – Machined brass cage.
   • TNG – Polyamide cage reinforced with glass fiber.

2. Internal clearance:

   • C3 – Greater than normal clearance.
   • C4 – Clearance greater than C3.

3. Precision class:

   • P0 – Normal class.
   • P4 – High precision.

Bore Diameter Designation

For bore diameters between 20 mm and 500 mm, the last two digits of the basic number are multiplied by five.
Example: 6205 = Bore diameter of 25 mm (5 x 5).

For diameters below 20 mm, a special code applies:

• 00 – 10 mm.
• 01 – 12 mm.
• 02 – 15 mm.

Sealing Options – Key to Longevity

Choosing the right sealing ensures protection against contamination and moisture:

• Z, ZZ – Metal shields.
• RS, RSR, 2RS – Contact rubber seals.
• RZ, 2RZ – Non-contact, low-friction seals.

Examples of Bearing Designations

1. 6004 ZZ NR NSK – Single-row deep groove ball bearing, 20 mm bore, metal shields, and snap ring groove.
2. RNU2206-E-XL-TVP2 – Cylindrical roller bearing without inner ring, plastic cage.

Why Understanding Bearing Designations Matters

Knowledge of bearing designations enables:

• Accurate selection for specific applications.
• Replacement with compatible models.
• Enhanced machine performance through proper component matching.

FAQ

1. What does C3 in a bearing designation mean?
   C3 indicates greater internal clearance, suitable for higher speeds and temperatures.

2. What do the letters ZZ signify?
   Metal shields on both sides of the bearing, protecting against small contaminants.

3. How do I determine the bore diameter of a bearing marked 6304?
   Multiply the last two digits (04) by five – the bore diameter is 20 mm.

4. Why is seal selection important?
   Proper seals protect against dirt, moisture, and increase bearing lifespan.

Conclusion

Understanding bearing designations is key to their effective selection and use. Explore our expert knowledge on simmering.pl, where you can find a wide range of bearings and professional technical advice.

Find the right bearing today and boost your machine's performance!