2022 October the First Week KYOCM Technical Knowledge: Improvement on Assembly Process of Special Double row Cylindrical Roller Bearing 782726

Abstract: By printing the roller size deviation instead of printing the number, the sleeve closing rate and the utilization rate of surplus products of the 782726 double row cylindrical roller bearing have been improved, and the cost has been reduced, and considerable economic benefits have been achieved.

Keywords: cylindrical roller bearing; Double row bearing; Sheathing; assembling



782726 special double row cylindrical roller bearing has high price and strict process requirements. When assembling the sleeve, the dimensions of the two roller groups in the bearing must be the same. This requirement is guaranteed by printing the sequence number, that is, the number of rows of this batch of bearings shall be printed on the side of the cage for each batch of products. However, during the inspection of finished products, the appearance of a group of cages or struts in the bearing is unqualified, and another group of rollers with the same serial number can not be used, resulting in cost losses.



1 Original assembly process

Install rollers → print sequence number → install prop → electric rivet prop → surface grinding → electric rivet head → demagnetization cleaning → pick two groups of rollers with the same serial number → group inner and outer rings → sleeve fitting → acid pen number → appearance and finished product inspection.


Disadvantages of printing sequence number:

(1) The labor intensity is high, and it is easy to lose or duplicate numbers. For example, for 800 sets of 782726 bearings in a batch, the number 1~800 must be printed twice (two rows of rollers in a set of bearings are printed with the same sequence number). During the printing process, the number is broken or the energy is not concentrated, and the number is forgotten or the wrong number is inevitable, so the number is lost or repeated. The larger the batch is, the more such errors are, which affects the fitting rate.


(2) Before assembling, the roller group with the same serial number shall be selected to rewrite the steel grade with a red pencil, so as to enhance the marking and facilitate assembling. Selecting in pairs is a waste of time, and it is not suitable to find the number.


(3) The specific size of roller group with printed serial number is unknown during sleeve fitting, and the sleeve fitting efficiency is low due to the roller deviation range recorded during roller fitting.


(4) The remaining roller group can not be used, and one group with the same bearing serial number is not qualified in appearance, and the other group can not be used. The cost loss of the frame and the support is caused by the rack lifting, and the weight and size of the roller are reused, resulting in large cost loss.


2 Improved process

Roller installation → roller size deviation printing → pillar installation → electric rivet pillar → plane grinding electric rivet head → demagnetization cleaning → size selection of inner and outer rings → sleeve fitting → acid pen numbering → appearance and finished product inspection.


Advantages of changing printing roller size deviation:

(1) It can reduce the labor intensity of assembly workers and avoid the phenomenon of missing or wrong numbers. The size deviation of roller group is generally - 8~+8 μ Even numbers between m and "+" sign of positive deviation are not printed, so only negative deviation is printed in two digits, which is easy to operate and greatly reduces labor intensity.


(2) It can improve production efficiency and shorten production cycle. The cleaned roller group does not need to repeatedly select the same group of serial numbers, as long as the deviation is the same, it can be sleeved, and the compression is a time-consuming process.


(3) The efficiency and rate of closing have been greatly improved. The theoretical clearance value can be directly calculated by roller deviation and internal and external raceway size deviation during sleeve fitting. The nesting rate increased from about 90% to 99%, without multiple trials.

(4) The remaining roller group can be reused to reduce the cost loss.


More about KYOCM Cylindrical Roller Bearing:

KYOCM cylindrical roller bearings can meet the challenges of applications faced with heavy radial loads and high speeds. Accommodating axial displacement (except for bearings with flanges on both the inner and outer rings), they offer high stiffness, low friction and long service life. KYOCM cylindrical roller bearings include single row cylindrical roller bearings, double row cylindrical roller bearings and four row cylindrical roller bearings.


Cylindrical roller bearings are also available in sealed or split designs. In sealed bearings, the rollers are protected from contaminants, water and dust, while providing lubricant retention and contaminant exclusion. This provides lower friction and longer service life. Split bearings are intended primarily for bearing arrangements which are difficult to access, such as crank shafts, where they simplify maintenance and replacements. 

Cylindrical Roller Bearing