Gearbox with gear synchronizing device

A change-speed gearbox, in which an input shaft continuously connected to an engageable and disengageable main friction clutch can be brought into driving connection with an output shaft by means of gear wheel stages, each associated with one gear ratio, or by means of a central synchronizing gear mechanism, and in which the loose wheels of the gear wheel stages associated with the gear ratios can each be coupled to their shaft by means of an associated gear wheel clutch without synchronizing elements, and in which, in the event of a gear change to a higher gear, the synchronizing gear mechanism can be brought into an “upshift” synchronization state by engagement of an associated frictional connection, in which state the speed of the input shaft can be adjusted to the lower synchronous speed corresponding to the higher gear to be selected, and in which, in the event of a gear change to a lower gear, the synchronizing gear mechanism can be brought into a “downshift” synchronization state by engaging an associated frictional connection, in which state the speed of the input shaft can be adjusted to the higher synchronous speed corresponding to the lower gear to be selected, a gear wheel stage having a transmission ratio greater than 1, the said gear wheel stage belonging to the synchronizing gear mechanism, being connected into the drive connection between the input and the output shaft in the “downshift” synchronization state, characterized in that the main clutch is held in the engaged state during each gear change, and a gear wheel stage having a transmission ratio less than 1 in the synchronizing gear mechanism being connected into the drive connection between the input and the output shaft in the “upshift” synchronization state.