Abstract: Balls to be moved radially outward by a centrifugal force are held in a clutch hub, and projections extending around the outer circumferences of the balls are united with a synchronizer ring. Those portions of the projections, which radially confront the balls, are formed with slopes for establishing an axial force to push the synchronizer ring away from the spline piece on the basis of the centrifugal force of the balls. Thus, the axial force for disengaging the synchronizer ring from a rotating member to be synchronized can be increased to prevent the chatter at a low number of revolution and to effectively eliminate the drag torque at a high number of revolution.

Abstract: A gear speed change system includes an input shaft, an output shaft coaxial therewith, a first counter shaft disposed parallel to the input and output shafts, and a second counter shaft coaxial with the first counter shaft. The input shaft and the first counter shaft, and the second counter shaft and the output shaft are coupled at a fixed ratio, respectively. One of gear sets selectively couples the input shaft to the second counter shaft and the output shaft to the first counter shaft, respectively. A clutch is provided between the first and the second counter shafts. With this construction, speed changes by the first counter shaft, the second counter shaft, and the combination of the first and second counter shafts may be effected, thereby reducing the number of required gear sets as compared with that of the speed change steps. The first counter shaft and the second counter shaft may be replaced with each other.

Abstract: A power transfer device adapted for use in combination with a primary transmission for an automotive vehicle, including a housing, a first output shaft rotatably mounted on the housing and having an input end for drive connection to an output shaft of the power transmission and an output end for drive connection to a first set of road wheels, a second output shaft rotatably mounted within the housing in parallel with the first output shaft and having an output end for drive connection to a second set of road wheels, a drive member rotatably mounted on the first output shaft, a driven member mounted on the second output shaft for rotation therewith and being drivingly connected to the drive member, a center differential in the form of a planetary gear unit mounted on the first output shaft and having a first output element in drive connection to the first output shaft and a second output element for drive connection to the drive member, and a changeover mechanism arranged between the planetary gear unit and th