The invention discloses a power-interrupting-free shifting speed changing box of an
electric vehicle and a shifting control method of the power-interrupting-free shifting speed changing box. The speed changing box comprises a first gear pair mechanism, a second gear pair mechanism, a disc
clutch and a shifting control mechanism, in the shifting control mechanism, a first gear overrunning
clutch and a control overrunning
clutch are mounted in corresponding gears, a control friction plate is fixed on a roller
retainer and a roller shifting fork of the first gear overrunning clutch, a wave spring is mounted in an annular groove in an end surface of a second control gear, and a control pressure plate is axially pre-tightened through the wave spring, is clamped in the annular groove in the end surface of the second control gear and rotates along with the second control gear. By the shifting control method of the speed changing box, first gear engaging, second gear engaging and gear reversing actions can be realized and do not intervene. By the power-interrupting-free shifting speed changing box of the
electric vehicle, the problem of interrupting of shifting power of the traditional AMT is solved, and a smooth speed ratio switching process can be realized. In addition, by the structure, a shifting fork and a shifting fork shaft are further omitted, the
system structure is greatly simplified, and the total weight of a transmission is reduced.