Solder joint fatigue life predictions for CSP package under power cycling;

The paper uses the theory of lever specific property of planet gear mechanism in analysing power circulation of the reduction of earth reamer auger of double spiral for 1st time and in making sure whether the reduction has power circle quickly and accurately.

So in this paper,based on the characteristic that of the three basic links in a differential gear train two must be either the driving or the driven,three new efficiency formulas are obtained;the power flow analysis,the determination of circulation power and the efficiency calculation are organically combined for research;meanwhile,the relationship between the power flow .

When a closed 3K planetary gear drive is designed,in order to forbid it to produce circulatory power flow,for a new method deciding its original/circulatory mechanism has been given in this paper.

The positive sign mechanism has circulating power load.

In some of them there will exist the circulating power load and so the transmission efficiency will be lower and sometimes self-locking may arise while in others there will not exist circulating power load.