For solving the problem of correct position in planetary gear mechanism

aiming at the interference problem of planetary mechanism for single planetary gear

the basic method of aligning the planes and confirming the assembly relationship is proposed.Aiming at the assembly problem of many planetary gears

the formula of planetary gear relative angles in installation stage is deduced

and a method of virtual assembly of planetary mechanism with many planetary gears is proposed.Finally

taking the RV250reducer as example

no inference assembly is accomplished

which is the foundation of mechanism motion and dynamics analysis.