The code of non-standard size bearing is composed of basic code, pre code and post code. The basic code consists of two parts: type code and dimension expression; The codes of front and rear bearings are the same as those of common bearings.


(1) Type code


Same as common bearings, see table 2-1.


(2) Dimension representation


1) There are two ways to express the size series code.


① The non-standard outer diameter or width (height) dimension shall be taken as the closest diameter series or width (height) series by comparing the standard dimension or according to the rules of external dimension extension specified in GB / t273.2 and GB / t273.3, and the letter shall be added after the basic code, as shown in table 2-19.


Table 2-19 representation of dimension series


letter


meaning


X1


X2


X3


Non standard outer diameter


Width (height) non standard


Outside diameter, width (height) non standard (standard inside diameter)


② When the non-standard inner diameter, outer diameter and width (height) dimension can not be compared with the standard dimension or according to the external dimension extension rules specified in GB / T 273.2 and GB / T 273.3, it shall be represented by indefinite series, as shown in table 2-20.


Table 2-20 representation of dimension series of indefinite series


Bearing type


Indefinite series


keep on record


Width (height) series code


Diameter series code


Radial bearing


0（4）


six


1. The indefinite series of double row angular contact ball bearing is 46


2. "O" is omitted when indefinite series 06 is combined with type code (except tapered roller bearing and double row deep groove ball bearing)


thrust bearing


one


two


seven


One way thrust bearing, indefinite series 17


Two way thrust bearing, indefinite series 27


2) The inner diameter is expressed according to table 2-21.


Table 2-21 inner diameter representation


internal diameter


Representation


Standard size


According to table 2-5


Non standard size


The integer below 500mm which can be divided by 5 is expressed by quotient divided by 5. Other dimensions are directly expressed by actual inner diameter mm, but shall be separated from dimension series code by "/"


Example: 66 / 6.4 - deep groove ball bearing, indefinite series, inner diameter 6.4mm;


61700 X1 - a deep groove ball bearing, non-standard outer diameter, close to diameter series 7;


62 / 14.5 - deep groove ball bearing, size series 02, inner diameter 14.5mm;


52706 - bidirectional thrust ball bearing, indefinite series, inner diameter 30mm


3) The dimension of the bearing is expressed as:


"/ inner diameter × external diameter × "Mm of actual width"


Example: K / 13 × seventeen × 13 -- needle roller and cage assembly, FW = 13mm, EW = 17mm, be = 13mm;


HK/12 × seventeen × 15 -- needle roller bearing with punched outer ring, FW = 12mm, d = 17mm, B = 15mm.


4) When the codes of several non-standard bearings of the same type with little difference in external dimensions are the same, the basic codes shall be distinguished by adding the symbol "-" followed by the serial numbers 1, 2, 3.


Example: 61700x1 - 1


61700X1 -2


52706- 152706-2