The method of determining the size of fitting ring in time of reaching assembly precision with fitting assembly method has been studied, two formulae for calculation of the size of fitting ring have been gotten.

On the basis of constructure character of universal_joint cross couping,This paper analyses assembly method of universal_joint and axial socket hole,designs a kind of assist technological equipment to improve assembly method and raise assembly precision.

This technique forecasts the products assembly precision and assistants designers to get corresponding optimum assembly process to pre-control the products quality before the actual assembly.

Base on the in-situ measurement and control of the assembling accuracy of chain -drawingoil machine, the measuring method of these physical parameters including relative plane, parallel of the plane, line, parallel of the line,and coplane of the line is studied, and a set of laser measuring system with high accuracy, wide-range application, easy operation is developed.

Meticulous process and improving assembly accuracy;

In the case of different methods for ensuring the assembly accuracy,some problems should be paid attention to when ascertaining composed link dimension tolerance by using assembly dimension chain.

Through calculating and analyzing the actual assembly accuracy, the paper establishes two ways to enlarge dimensional tolerance to reduce machining cost and raise economic efficiency.

208 centripetal ball bearing made by a ball bearing factory of Hunan as an example, the bearing quality loss caused by the assembly quality is analyzed quantitatively, and the theoretical basis for the quality control of assembling tolerance is provided.

208 centripetal ball-bearing made by a ball-bearing factory of Hunan as an example,the bearingquality loss caused by the assembly quality is analyzed quantitatively,and the theoretical basis forthe quality control of assembling tolerance is provided.