| 摘要 |
The invention relates to a variable-speed transmission for motor cars, in particular a manual gear-box in the form of a synchronized lay-shaft transmission having several forward speeds and one reverse motion, in which the gears of the reverse motion (11, 12) are also constantly meshing and in which the pairs of gears are selectively shifted into the flux of forces by means of a shifting clutch (13). In order to permit low-noise shifting into the reverse motion, the latter (11, 12) is provided with a synchronizer unit (17, 23). Considering, however, that this creates the risk that the reverse gear may be put in while the car is moving forward, a stop (9, 23) can be moved into the path of transmission of motion between a shift lever to be actuated by the driver and the shifting clutch (13) for the reverse motion, which stop occupies the engaged position when a predetermined traveling speed is exceeded and acts in this engaged position to block the actuation of the shifting clutch (13) for the reverse motion (11, 12) (FIG. 1). The stop is incorporated into the shifting clutch for the reverse gear. |
