Abstract: In the Standard of P.R.C《GB/T 4459.7-1998 Mechanical drawings— Representation of rolling bearings》, there is a convention in characteristic drawing of cone roller bearings. By contrasting the width of the drawing to the fact, the article points out two problems: to some cone Roller Bearings, the drawing can’t express the principle of a mechanical system in the assembly drawing; and is contradictory to the words in this standard. The paper provides some suggestions to solve the problem.

Key words: mechanical drawings, cone roller bearing, characteristic-drawing, assembly drawing, principle of a mechanical system