Vehicle transmission

A vehicle transmission comprising:

• a first input shaft having a plurality of first input gears;
• a second input shaft coaxially arranged with respect to the first input shaft and having a plurality of second input gears;
• a first clutch arranged to operatively transmit a driving torque of a power source to the first input shaft;
• a second clutch arranged to operatively transmit the driving torque of the power source to the second input shaft;
• a first output shaft having a plurality of first output gears engaged with selected ones of the first and second input gears to define a plurality of gear pairs that each selectively receives the driving torque from one of the first and second input shafts;
• a second output shaft having a plurality of second output gears engaged with selected ones of the first and second input gears to define a plurality of gear pairs that each selectively receives the driving torque from one of the first and second input shafts;
• a countershaft having a plurality of third output gears with the countershaft being disposed in parallel with the first and second output shafts such that the third output gears are engaged with selected ones of the first and second input gears to define a plurality of gear pairs that each selectively receives the driving torque from one of the first and second input shafts;
• and
• a plurality of gear selectors operatively disposed to selectively connect and disconnect the first output shaft to selected ones of the first output gears, the second output shaft to selected ones of the second output gears, and the countershaft to selected ones of the third output gears in order to selectively establish a plurality of forward driving speed ratios and at least one reverse driving speed ratio by selectively controlling the gear selectors and the first and second clutches,
• the first input gears, the second input gears, the first output gears, the second output gears and the third output gears being selectively connected such that
• only two sets of the gear pairs are used in establishing a torque transmitting path from one of the first and second input shafts to a final reduction gear output shaft when at least one of a forward gear is selected among the forward driving speed ratios that is other than a first forward gear,
• only four sets of the gear pairs are used in establishing a torque transmitting path from one of the first and second input shafts to the final reduction gear output shaft when the first forward gear is selected among the forward driving speed ratios, and
• only three sets of the gear pairs are used in establishing a torque transmitting path from one of the first and second input shafts to the final reduction gear output shaft when a reverse gear is selected.

A driving force transmission apparatus comprising:

• first input means for establishing a plurality of first input gears;
• second input means for establishing a plurality of second input gears;
• first clutch means for operatively connecting and disconnecting a driving torque of a power source to the first input means;
• second clutch means for operatively connecting and disconnecting the driving torque of the power source to the second input means;
• first output means for establishing a plurality of first output gears engaged with selected ones of the first and second input gears to define a plurality of gear pairs that each selectively receives the driving torque from one of the first and second input means;
• second output means for establishing a plurality of second output gears engaged with selected ones of the first and second input gears to define a plurality of gear pairs that each selectively receives the driving torque from one of the first and second input means;
• third output means for establishing a plurality of third output gears engaged with selected ones of the first and second input gears to define a plurality of gear pairs that each selectively receives the driving torque from one of the first and second input means;
• and
• gear engagement means for selectively connecting and disconnecting the first output means to selected ones of the first output gears, the second output means to selected ones of the second output gears, and the third output means to selected ones of the third output gears in order to selectively establish a plurality of forward driving speed ratios and at least one reverse driving speed ratio by selectively controlling the gear engagement means and the first and second clutch means,
• the first input gears, the second input gears, the first output gears, the second output gears and the third output gears being selectively connected such that no more than two sets of the gear pairs are used in establishing a torque transmitting path from one of the first and second input means to a final reduction gear output shaft when other than a first forward gear is selected among the forward driving speed ratios.