1
5th gear synchronizer clutch
3
Synchronizer ring (5th gear)
4
C-washer abutment points
6
Direction of rotation - output shaft
8
Synchroniser ring seating point
The axial force of the selector rod moves the shift collar in the direction of 5th gear.
With the movement of the shift collar, the C-washer is pressed against the synchroniser ring (upper abutment point). At the same time, the C-washer is supported on the synchroniser clutch (lower abutment point).
Because of the pressure of the C-washer on the synchroniser ring, this is pressed against the conical friction surface of the gearwheel and thus the presynchronisation starts.
As long as the shift collar and gearwheel rotate at different speeds, a turning torque is generated. This twists the synchroniser ring until the synchroniser ring abutment point touches the C-washer abutment point (arrow). The presynchronisation is over.
After the complete synchronisation process is finished, the shift collar moves over the splines of the synchroniser ring into the splines of the gearwheel. In the process, the two C-washers are pushed away inwards against the spring effect of the spring washer.
4
C-washer abutment points
Because of the shift construction of the transaxle, the axial force of the selector rod moves the 5th gear shift collar in the opposite direction to the 5th gear gearwheel.
As a result of this, the C-washer is pressed against the synchroniser ring (lower abutment point). At the same time, the C-washer is supported on the synchroniser clutch (upper abutment point).
Because of the pressure of the C-washer on the synchroniser ring, this is pressed against the conical friction surface of the gearwheel. The synchroniser ring thereby presses against the conical friction surface of the gearwheel and in doing so slows down the input shaft.
This ensures that the speed of the transmission shafts is equal to zero while the reverse gear idler gear is inserted. The so-called 'crunch' during rapid engagement of reverse gear is thus prevented. The prerequirement however is that the vehicle is no longer moving while reverse gear is being engaged.
Neutral position
In the neutral position of the 5th gear synchroniser clutch, the C-washers are exactly perpendicular to the Y-axis. Consequently, there is also no pressure exerted on the synchroniser ring.
Slowing the input shaft as reverse gear is engaged
The 5th gear synchroniser is firmly connected to the output shaft. The vehicle is stationary during engagement of reverse gear, whereby the output shaft does not turn. On the other hand, the input shaft with the gear for 5th gear and the 5th gear gearwheel on the output shaft rotate at engine speed. During the shift operation into reverse gear, the 5th gear synchroniser ring is briefly pressed against the 5th gear gearwheel and slows it down, whereby in turn the input shaft is slowed down.
Component Description
1
Open cylinder roller bearing
2
Output shaft with differential drive gear
4
1st gear double synchronizer
5
1st/2nd gear synchronizer clutch with reverse gear
6
2nd gear double synchronizer
9
3rd gear double synchronizer
10
3rd/4th gear synchronizer clutch
11
4th gear single synchronizer
16
5th gear single synchronizer
17
5th gear synchronizer clutch
All the gears in the manual transaxle (iB5) are located on the output shaft.
The reverse gear is a component of the 1st/2nd gear synchronizer clutch.
The output shaft is a hollow shaft through which transmission fluid flows. Bores in the hollow shaft ensure lubrication of the needle bearings and the synchronizer clutches.
An oil thrower behind the cylinder roller bearing (transaxle housing side) ensures the necessary oil supply for the hollow shaft.
3
Reverse gear drive wheel
The reverse gear is permanently attached to the input shaft. The reverse gear wheel is located on the output shaft.
The reverse idler gear runs freely in a bearing seat on the reverse gear idler shaft.
If the reverse gear is engaged, the reverse idler gear is moved in the axial direction. It is moved until the reverse gear, the reverse gear wheel and the reverse idler gear engage. The direction of rotation of the output shaft is reversed when the three gears engage.
All three gears have straight-cut teeth.
The reverse gear switch is located at the side.
The differential assembly is built into the transaxle housing.
The drive torque is transmitted to the differential by the crown wheel which is bolted to it.
The differential assembly contains differential pinion gears mounted on a spindle and the axle halfshaft pinion gears which connect to the front wheel axle halfshafts through helical gearing.
The axle halfshaft pinion gears can revolve around the differential pinion gears when the road wheel speeds are different (e.g when cornering).
3
Return spring from reverse gear position
4
Reverse gear gearshift lever
6
Shift rod - 5th gear/reverse gear
The gearshift locking bush prevents two gears from being engaged at the same time.
The selector interlock maintains engagement of the selected gear.
Both the shift and the select process is performed through the selector shaft.
