side of the controllable brake device bk 101 is fixed in a housing h 100 and the planetary gear set dg 101 is also fixed in the housing h 100 which mainly consists of planetary gear set dg 101 constituted by a sun wheel w 101 and an outer annular wheel w 102 and at least a planetary wheel w 103 including through gears engaging with each other or through friction wheels mutually performing friction transmissions to form the planetary gear set function and also constituted including the rotation shaft s 101 the rotation shaft s 102 the rocker arm of planetary wheel a 103 the rocker arm of planetary wheel as 103 u2032 the sleeve type rotation shaft of planetary wheel as 103 and the sleeve type rotation shaft of planetary wheel as 103 u2032 and a bearing for being installed in a shell of the planetary gear set dg 101 and the planetary gear set dg 101 is fixed in the housing h 100 rocker arm of planetary wheel a 103 having one end provided for allowing the planetary wheel w 103 to rotate and link and the other end being sleeved on the rotation shaft s 101 through the sleeve type rotation shaft of planetary wheel as 103 and the rocker arm of planetary wheel a 103 or the sleeve type rotation shaft of planetary wheel as 103 is connected to an action side of the controllable brake device bk 101 and.