What Are Our Concerns About Bearings（28）

Q1: How to understand the structure code of rolling bearing in mechanical design?

A:Rolling bearing code consists of basic code, pre-code and post-code, represented by letters and numbers.  The code meanings are as follows:  

1. Basic code  

The basic code is used to indicate the inner diameter, diameter series, width series and type of bearings, generally five digits, first described as follows:  

• 1) Bearing inner diameter is represented by basic code number one from the right and H digit.  For the common inner diameter d=20 ~ 480mm bearing inner diameter is generally a multiple of 5, these two numbers represent the bearing inner diameter size divided by 5 quotient, such as 04 represents D = 20mm;  12 means d = 60mm and so on.  For bearings with inner diameters of 10mm, 12mm, 15mm and 17mm, the inner diameters are 00, 01, 02 and 03 respectively.  For bearings with inner diameter less than 10mm and greater than 500mm, the inner diameter expression method is otherwise stipulated, which can be referred to GB/T272-93.  
• 2) The diameter series of bearings (that is, the bearing with the same structure and the same inner diameter changes in the outer diameter and width series) are represented by the third digit from the right of the basic code.  For example, for centripetal bearings and centripetal thrust bearings, 0 and 1 represent extra-light series;  2 indicates light series;  3 indicates the medium series.  4 indicates the repeated series.  The thrust bearing is the same as the centripetal bearing except that 1 is used to represent the extra-light series.  
• 3) The width series of bearings (that is, the change series of bearing width with the same structure, inner diameter and diameter series) is represented by the fourth digit from the right of the basic code.  When the comparison of the width series diameter series is listed as 0 series (normal series), the width series code O can not be marked in the code for most bearings, but for self-aligning roller bearings and tapered roller bearings, the width series code 0 should be marked.  
• Diameter series code and width series code collectively referred to as size series code.  
• 4) Bearing type codes are represented by the fifth digit from the right of the basic code (for cylindrical roller bearings and needle roller bearings and other types of codes are letters).  

2. Postcode  

Bearing postcode is to use letters and numbers to express the bearing structure, tolerance and special requirements of materials, etc.  Postcode is a lot of content, here are a few commonly used code.  

• 1) The internal structure code refers to the different internal structure of the same type of bearing, which is represented by letters followed by the basic code.  For example, angular contact ball bearings with contact angles of 15°, 25° and 40° are denoted by C, AC and B respectively.  
• 2) The tolerance grade of bearings is divided into class 2, class 4, class 5, class 6, class 6X and class 0, a total of 6 grades, successively from high to low, and its codes are/PZ, / P4 ‘/ PS, / P6, / P6X and/PO respectively.  
• In the tolerance class, class 6X is only applicable to tapered roller bearings;  Grade 0 is general grade and is not marked in the wheel bearing code.  
• 3) The commonly used radial clearance series of bearings are divided into 6 groups, namely group 1, group 2, group 0, group 3, group 4 and group 5. The radial clearance is successively from small to large.  O group clearance is a commonly used clearance group, which is not marked in the bearing code, and the other clearance groups are respectively represented by/C1, / C2, / C3, / C4 and/C5 in the bearing code.  

3. Pre-code  

Bearing prefix code used to represent bearing parts with letters.  For example, L represents the separable ring of the separable bearing;  K represents the rolling body and cage components of bearings, etc.  

There are many types of rolling bearings in practical application, and the corresponding bearing codes are also more complex.  The code introduced above is the basic and common part of the bearing code. If you are familiar with this part of the code, you can identify and check the common bearings.  Detailed code method for rolling bearings can be referred to GBT272-93.  Note: the ordinal number from right to left of the base code is indicated by one to five.  

 It’s basically a number or a letter at the beginning  

• 1 self-aligning ball bearing 2 self-aligning roller bearing or thrust self-aligning roller bearing  
• Tapered roller bearing double row deep groove ball bearing  
• 5 thrust bearing 6 deep groove ball bearing  
• Angular contact ball bearing 8 thrust cylindrical roller bearing  
• N Cylindrical roller bearing U Outer spherical contact ball bearing  
• Q Four point contact ball bearing  

Q2: Flat thrust needle roller bearing outer diameter 75 inner diameter 55 thickness 5, what model is it?

A:No corresponding bearing was found, only 55 inner diameter, 78 outer diameter and 5 width. AXK5578 and 2 AS5578 are used together.

Q3: What type of plane thrust needle roller bearing 150*190*7 is?

A:AXK150190 with gasket

Q4: What is the size of needle roller bearing HK1217?

A:The inside diameter is 12, and the width is 17. Because this model is a non-standard model, the od may be 18.

Q5: When rolling bearings are lubricated by oil, what are the commonly used lubrication methods?  

A:oil bath lubrication, drop lubrication, splash lubrication, spray lubrication, oil mist lubrication, etc  

Q6: How to find the tapered roller bearing model?

A:For example, 32216,3 is taper series, 22 is width series, 16 inner diameter code, 16 times 5 that is, the bearing inner diameter is 80;  Difference with 32316: different width, different outside diameter, same inside diameter.

Q7: How to distinguish centripetal ball bearings from centripetal ball bearings how to distinguish thrust bearings?  

A:If they are ball bearings, they can be distinguished as follows: Centripetal spherical ball bearings are usually double rows, that is, two rows of centripetal ball bearings are also called deep groove ball bearings. Usually, there is only one row of steel balls and thrust ball bearings have one-way and two-way points. The size of two laps is about the same, but the outer diameter of the moving ring is smaller than that of the fixed ring.  Thrust bearing is angular contact bearing, its outer ring inside is slope surface, thickness is not the same as the upper and lower, and centripetal ball bearing is easy to distinguish, generally used in the thrust place.