Internal gearshift mechanism
Layout of the internal gearshift mechanism
| Item | Description |
|---|---|
| 1 | Electric shift motors integrated in the TCM |
| 2 | Gear selector drum B with spur gear Comments: Controls the selector forks for 2nd/6th gear and 4th/reverse gear |
| 3 | Double spur gear 1 |
| 4 | Double spur gear 2 |
| 5 | Gear selector drum A with spur gear Comments: Controls the selector forks for 1st/5th gear as well as 3rd gear |
The gears are shifted by means of two brushless DC motors, which each actuate a gear selector drum via a two-stage transmission ratio. The gear selector drums each have one shift slot for moving the selector forks. As a result of using the gear selector drum principle, no additional mechanical lock is required in order to prevent more than one gear being engaged at the same time in the same sub-transmission in the event of a fault.
Layout of the gearshift system (schematic diagram)
| Item | Description |
|---|---|
| 1 | Gear selector drum B with spur gear |
| 2 | Selector fork - reverse gear/4th gear |
| 3 | Selector fork - 3rd gear |
| 4 | Selector fork - 1st/5th gear |
| 5 | Gear selector drum A with spur gear |
| 6 | Selector fork - 2nd/6th gear |
Each gear selector drum actuates two selector forks. The total angle of rotation of the gear selector drums is limited by means of two stops which are cast as an integral part of the transmission housing.
The angle of rotation of the gear selector drum A is 200°. The angle of rotation of the gear selector drum B is greater and measures 290 deg, as this gear selector drum is used to shift four gears.
Overview of the gearshift system
| Item | Description |
|---|---|
| 1 | Gear selector drum with spur gear |
| 2 | Selector fork - reverse gear/4th gear |
| 3 | Selector fork - 3rd gear |
| 4 | Selector fork - 1st/5th gear |
| 5 | Gear selector drum with spur gear |
| 6 | Shift slot |
| 7 | Lower cam |
| 8 | Selector fork - 2nd/6th gear |
| 9 | Sliding block |
| 10 | Upper cam |
The shift slot in the gear selector drum has two counter-running cams on its circumference, which are offset by 180°. A slider which is connected to the selector fork is moved via the shift slot. If the slider moves up or down on the cam then the selector fork is moved accordingly in an axial direction, and as a result either a gear is engaged or the synchronizer assembly is moved to the neutral position.
Function of the gear selector drum
| Item | Description |
|---|---|
| 1 | Shift slot of gear selector drum A Comments: In the colored area the angle of rotation is 200°. |
| 2 | Lower cam |
| 3 | Selector fork for 3rd gear with slider |
| 4 | Upper cam |
| 5 | Selector fork for 1st/5th gear with slider |
| 6 | Lower end position (rotation angle 0°) |
| 7 | Rotation angle 10° Comments: The selector fork for 1st/5th gear is moved axially and 1st gear is engaged. |
| 8 | Rotation angle 55° Comments: Neutral position between 1st gear and 3rd gear |
| 9 | Rotation angle 100° Comments: The selector fork for 3rd gear is moved axially and 3rd gear is engaged. |
| 10 | Rotation angle 145° Comments: Neutral position between 3rd gear and 5th gear |
| 11 | Rotation angle 190° Comments: The selector fork for 1st/5th gear is moved axially and 5th gear is engaged. |
| 12 | Upper end position (rotation angle 200°) |
Function of the gear selector drum B
| Item | Description |
|---|---|
| 1 | Selector fork for 2nd/6th gear with slider |
| 2 | Shift slot of gear selector drum B Comments: In the colored area the angle of rotation is 290°. |
| 3 | Upper cam |
| 4 | Lower cam |
| 5 | Selector fork for reverse/4th Gear with slider |
| 6 | Lower end position (rotation angle 0°) |
| 7 | Rotation angle 10° Comments: Selector fork for reverse/4th gear is moved in an axial direction and reverse gear is engaged. |
| 8 | Rotation angle 55° Comments: Neutral position between reverse gear and 2nd gear |
| 9 | Rotation angle 100° Comments: The selector fork for 2nd/6th gear is moved axially and 2nd gear is engaged. |
| 10 | Rotation angle 145° Comments: Neutral position between 2nd gear and 4th gear |
| 11 | Rotation angle 190° Comments: Selector fork for reverse/4th gear is moved in an axial direction and 4th gear is engaged. |
| 12 | Rotation angle 235° Comments: Neutral position between 4th gear and 6th gear |
| 13 | Rotation angle 280° Comments: The selector fork for 2nd/6th gear is moved axially and 6th gear is engaged. |
| 14 | Upper end position (rotation angle 290°) |