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The fourth digit of the basic code from right to left indicates the type and structure code of the bearing (the bearing model is 3 digits, and the fourth digit from right to left defaults to 0).
Class “0” indicates deep groove ball bearing
Category “1” refers to self-aligning ball bearings
Category “2” denotes short cylindrical roller bearings
Category “3” indicates self-aligning roller bearings
Category “4” refers to needle roller bearings (long cylindrical roller bearings)
Category “6” indicates angular contact ball bearings
“7” indicates tapered roller bearings
Category “8” refers to radial thrust ball bearing
Category “9” denotes thrust roller bearings
The basic model has two numbers or letters (or two numbers or letters) from left to right, indicating the type structure code:
“6” indicates deep groove ball bearing
“0” indicates self-aligning ball bearing (for example, 1204 bearing, the left number defaults to 0)
“2” indicates self-aligning roller bearing
“29” indicates thrust self-aligning roller bearing
“N” stands for cylindrical roller bearing (n, Nu, NJ, NF, NUP, NN stands for short cylindrical roller. Na, NK stands for needle roller bearing)
“7” indicates angular contact ball bearing
“3” indicates tapered roller bearing
“51” indicates radial thrust ball bearing