Gearbox (front wheel drive - longitudinal)
Non co-axial straight-mounted with front-, mid- or rear engine |
Non co-axial gearboxes are used with all drive-train set-ups, except front engine with rear-wheel drive. In the above figure it is mounted as a front-wheel drive behind the straight mounted engine, clutch and the final
drive. Typical for the straight mounted engine, is the crown- and bevel wheel gearing in the final drive.
This gearbox is often found behind the straight front engine, clutch and the axel drive. More seldom it is rear mounted, either in front of the rear axle in the rear-engined vehicle (Porsche 911) or behind it in the case of a mid-motor (Porsche Boxster).
Engine torque from the left to the upper drive shaft |
The lower, center shift-collar (with reverse gear wheel) is shifted to the right. The smallest diagonally cut gearwheel on the axle drive shaft on top drives the largest diagonally cut gearwheel on the right beside the shift-
collar onto the drive shaft below.
The lower, center shift-collar is shifted to the left. The second-smallest diagonally cut gearwheel on the axle drive shaft above, drives the second largest diagonally cut gearwheel on the left next the shift-collar, onto the
drive shaft below.
The upper, left shift-collar is shifted to the right. Next to it, on the right, the diagonally cut gearwheel drives the gearwheel linked with it below, onto the drive shaft.
The upper left shift-collar is shifted to the left. Next to it, on the left, the diagonally cut gearwheel drives the gearwheel below it, onto the drive shaft
The upper, right shift-collar is shifted to the right. Next to it, on the right, the largest diagonally cut gearwheel on the axle drive shaft, drives the smallest diagonally cut gearwheel onto the drive shaft below.
The runback wheel on the left, next to the 1st gear, on an additional shaft, is shifted to the left. The torque is transferred by the only straight-cut gearwheel on the drive shaft, through the reverse gearing of the shift-collar
of the 1st/2nd gear, onto the drive shaft below
Drive torque to the left to the bevel-/crown gear. |
It can also be seen that the gearbox was developed from a four-speed transmission. The fifth gear (on the right) has been added afterwards. It still has an unsynchronised reverse gear, which can be recognised by
the straight-cut gearing. The vehicle must be stopped completely to be able to engage the reverse gear. 10/08
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