HOW TO CALCULATE BEARING DIMENSION FROM BEARING NUMBER

 

HOW TO CALCULATE BEARING DIMENSION FROM  BEARING NUMBER

                          In today’s world, we are surrounded by machinery which make our work easy & provide comfort. In all these machinery we found one component common, it is a bearing. Therefore it becomes necessary to know more about bearings. Here we are going to discuss about finding bearing dimension from its number. It will help to finalize the bearing for particular application in machine.

 

                   The above picture illustrates the complete bearing internal parts.

The bearing is designated by number which has complete information about the bearing in coded form. Let’s decode these numbers.

 

For Example:- We take one bearing 6205 ZZ.

                    6                             2                              05                                     ZZ

   

        Bearing Type         Bearing Series    Bearing Inner dia              Shield type

First digit in the bearing defines bearing type in code as per table-1 given below.

 

                      

Bearing Codes	Types of Bearings
1	Self-aligning Ball Bearing
2	Spherical Roller Bearing
3	Double Row Angular Contact Ball Bearing
4	Double Row Ball Bearing
5	Thrust Ball Bearing
6	Single- Row Deep Groove Ball Bearing
32/T	Tapered Roller Bearing
R	Inch Bearing
N	Cylindrical Roller Bearing
NN	Double –Row Roller Bearing
NA	Needle Roller Bearing
BK	Needle Roller Bearing with Closed ends (Drawn Cups)

                          Table 1------bearing code with type of bearings

        For bearing 6205ZZ, the first digit defines that bearing is Single- Row Deep Groove Ball Bearing.

          The e second digit in the bearing defines the bearing series or application as per the table-2 given below. For bearing 6205, digit 2 defines it is for light application.

Series Codes	Series Description
0	Extra Light
1	Extra Light Thrust
2	Light
3	Medium
4	Heavy
8	Extra Thin Section
9	Very Thin Section

                                       Table 2------ Series code with series description

          The third and fourth digit define the inner diameter (Bore size) of the bearing in mm as per the table-3 given below. For bearing 6205ZZ, bore size is 25 mm.

 

Third & Fourth digit	Bore Size(in mm)
00	10
01	12
02	15
03	17
04	20 (04 x 5)
05	25 (05 x 5)
06	30 (06 x5)
07	35 (07 x 5)
08	40 (08 x 5)
09	45 (09 x 5)
10	50 (10 x 5)

                                Table 3------ Third & fourth digit with bore size

         The last alphabets or alphanumeric define the shield (sealing) type as per the               table -4 given below. For 6205ZZ, it is both side steel shielded.

Types of Shielding	Description
Z	One side steel shielded
ZZ	Both Side steel shielded
RS	One side rubber sealed
2RS	Both side rubber sealed
V	One side Non-Contact Seal
VV	Both Sides Non-Contact Seal
DDU	Both sides Contact Seals

                                      Table 4------ Type of shielding & its description

 

Some bearings are with clearance which is also mentioned in bearing number. Clearance is the total distance between the inner rings to the outer ring. Such as, when one among the rings is rotating and the other is fixed. Bearing clearance is of 5 types normal clearance, standard clearance, C2, C3, and C4.

Among them, normal clearance and C3 are the main clearance. The normal clearance shows no suffix. Standard clearance has no suffix as well as the prefix. C3 delivers faster running speed and higher temperature with no failure. C2 is less than standard clearance. At last, C4 shows an outcome faster than C3.

 

                        In such a way, we can find out bearing information from is number.