Automatic Transaxle System (F21)

Description

F21 Features
1. Easy-to-install FF 6-speed automatic transaxle
The F21 is a compact, lightweight, next-generation electronically controlled FF 6-speed automatic transaxle that employs a ravigne aux-type planetary gear. It employs a high-precision clutch hydraulic control system for smooth, highly responsive gear shift feel.
2. Adoption of centrifugal hydraulic pressure cancel clutch
When the rotation of the clutch increases, centrifugal force operations on the oil inside the clutch, hydraulic pressure increases, and the timing of clutch engagement becomes earlier. This cause, a difference in rotation between the input shaft and the output shaft, and shift shock may occur. To solve this, an additional chamber has been provided opposite the piston hydraulic pressure chamber. This causes centrifugal hydraulic pressure to operate in the opposite direction with the same force as the piston, counteracting the pressure of the piston hydraulic pressure chamber.
3. Adoption of integrated position sensor with TCU

The adoption of the integrated oil cooler has the following advantages:
(1) It allows the number of parts to be decreased (the wire harness can be simplified).
(2) Reliability is enhanced because there is no harness circuit between the TCU and shift position sensor.

Operation




List Of Operating Components






Operation Of Components





Procedure Of Operating Each Gear
1. "D" -1st gear
Power transmission pathway [Operating components: C1, F1]
Operating components:
C1, F1 (counterclockwise rotation is locked), B2 (ON when engine brake is operating)





(1) Input shaft (rotates clockwise) [same revolutions as the torque converter's turbine runner]
(2) Front planetary ring gear (rotates clockwise) [same revolutions as the input shaft]
(3) Front planetary pinion gear (rotates clockwise on its axis, orbits clockwise)
[because the front planetary sun gear is locked by the oil pump, it is pressed against the front planetary ring gear and orbits the sun gear while rotating on its axis (because the front planetary ring gear has internal gears, the rotational direction does not change)]
(4) Front planetary carrier (rotates clockwise)
[reduction: same revolution as the front planetary pinion gear orbit revolution]
(5) C1-CLUTCH (rotates clockwise) [connects the front planetary carrier and the rear planetary sun gear]
(6) Rear planetary sun gear (rotates clockwise) [same revolution as the front planetary carrier]
(7) Rear planetary short pinion gear (rotates counterclockwise on its axis)
[the rear planetary carrier tries to rotate counterclockwise, but the counterclockwise rotation is locked by one-way clutch F1.]
(8) Rear planetary long pinion gear (rotates clockwise on its axis)
[the rear planetary middle sun gear rotates counterclockwise (idling)]
(9) Rear planetary ring gear (rotates clockwise) [the rear planetary ring gear is rotated by the rear planetary long pinion gear (because the rear planetary ring gear has internal gears, the rotational direction does not change)]
(10) Counter drive gear (rotates clockwise) [because the rear planetary ring gear is installed on the counter drive gear, the rotational direction and the revolution are the same as the rear planetary ring gear]
(11) Counter driven gear (rotates counterclockwise)
(12) Differential ring gear (rotates clockwise)

Engine brake
When the engine brake is operating, driving force is transmitted from the tires.
2. "D" -2nd gear
Power transmission pathway [Operating components: C1, B1]





(1) Input shaft (rotates clockwise) [same revolutions as the torque converter's turbine runner]
(2) Front planetary ring gear (rotates clockwise) [same revolution as the input shaft]
(3) Front planetary pinion gear (rotates clockwise on its axis, orbits clockwise)
[because the front planetary sun gear is locked by the oil pump, it is pressed against the front planetary ring gear and orbits the sun gear while rotating on its axis (because the front planetary ring gear has internal gears, the rotational direction does not change)]
(4) Front planetary carrier (rotates clockwise)
[reduction: same revolution as the front planetary pinion gear orbit revolution]
(5) C1-CLUTCH (rotates clockwise) [connects the front planetary carrier and the rear planetary sun gear]
(6) Rear planetary sun gear (rotates clockwise) [same revolution as the front planetary carrier]
(7) Rear planetary middle sun gear is locked by B1-BRAKE
(8) Rear planetary short pinion gear (rotates counterclockwise on its axis, orbits clockwise)
(9) Rear planetary long pinion gear (rotates clockwise on its axis, orbits clockwise)
(10) Rear planetary ring gear (rotates clockwise)
[the rear planetary ring gear is rotated by the rear planetary long pinion gear (because the rear planetary ring gear has internal gears, the rotational direction does not change)]
(11) Counter drive gear (rotates clockwise)
[because the rear planetary ring gear is installed on the counter drive gear, the rotational direction and the revolution are the same as the rear planetary ring gear]
(12) Counter driven gear (rotates counterclockwise)
(13) Differential ring gear (rotates clockwise)
3. "D"-3rd gear
Power transmission pathway [Operating components: C1, C3]





(1) Input shaft (rotates clockwise) [same revolution as the torque converter's turbine runner]
(2) Front planetary ring gear (rotates clockwise) [same revolution as the input shaft]
(3) Front planetary pinion gear (rotates clockwise on its axis, orbits clockwise)
[because the front planetary sun gear is locked by the oil pump, it is pressed against the front planetary ring gear and orbits the sun gear while rotating on its axis (because the front planetary ring gear has internal gears, the rotational direction does not change)]
(4) Front planetary carrier (rotates clockwise)
[reduction: same revolution as the front planetary pinion gear orbit revolution]
(5) C1-CLUTCH (rotates clockwise) [connects the front planetary carrier and the rear planetary sun gear]
(6) C3-CLUTCH (rotates clockwise) [connects the front planetary carrier and the rear planetary middle sun gear]
(7) Rear planetary gear assembly (rotates clockwise)
[because the rear planetary short pinion gear and the rear planetary long pinion gear are engaged, both the pinion gears are locked due to the difference in the rotational directions, and kinematic energy of the rear planetary sun gear and rear planetary middle sun gear is transmitted to the rear planetary ring gear]
(8) Rear planetary ring gear (rotates clockwise) [same revolution as the rear planetary carrier]
(9) Counter drive gear (rotates clockwise)
[because the rear planetary ring gear is installed on the counter drive gear, the rotational direction and the revolution are same as the rear planetary ring gear]
(10) Counter driven gear (rotates counterclockwise)
(11) Differential ring gear (rotates clockwise)
4. "D"-4th gear
Power transmission pathway [Operating components: C1, C2]





(1) Input shaft (rotates clockwise) [same revolution as the torque converter's turbine runner]
(2) Front planetary ring gear(rotates clockwise) [same revolution as the input shaft]
(3) Front planetary pinion gear (rotates clockwise on its axis, orbits clockwise)
[because the front planetary sun gear is locked by the oil pump, it is pressed against the front planetary ring gear and orbits the sun gear while rotating on its axis (because the front planetary ring gear has internal gears, the rotational direction does not change)]
(4) Front planetary carrier (rotates clockwise)
[reduction: same revolution as the front planetary pinion gear orbit revolution]
(5) C1-CLUTCH (rotates clockwise) [connects the front planetary carrier and the rear planetary sun gear]
(6) Intermediate shaft (rotates clockwise) [same revolution as the input shaft]]
(7) C2-CLUTCH (rotates clockwise) [same revolution as the intermediate shaft]
(8) Rear planetary carrier (rotates clockwise) [same revolution as the intermediate shaft]
(9) Rear planetary short pinion gear (rotates clockwise on its axis, orbits clockwise) [because the rear planetary carrier rotates faster than the rear planetary sun gear]
(10) Rear planetary long pinion gear (rotates counterclockwise on its axis, orbits clockwise)
(11) Rear planetary ring gear (rotates clockwise)
[because the rear planetary long pinion gear's rotation is subtracted from the rear planetary carrier revolution, the rear planetary ring gear revolution is slower than those of the rear planetary carrier]
(12) Counter drive gear (rotates clockwise)
[because the rear planetary ring gear is installed on the counter drive gear, the rotational direction and the revolution is the same as the rear planetary ring gear]
(13) Counter driven gear (rotates counterclockwise)
(14) Differential ring gear (rotates clockwise)
5. "D"-5th gear
Power transmission pathway [Operating components: C2, C3]





(1) Input shaft (rotates clockwise) [same revolutions as torque converter's turbine runner]
(2) Front planetary ring gear (rotates clockwise) [same revolution as the input shaft]
(3) Front planetary pinion gear (rotates clockwise on its axis, orbits clockwise)
[because the front planetary sun gear is locked by the oil pump, it is pressed against the front planetary ring gear and orbits the sun gear while rotating on its axis (because the front planetary ring gear has internal gears, the rotational direction does not change)]
(4) Front planetary carrier (rotates clockwise)
[reduction: same revolution as the front planetary pinion gear orbit revolution]
(5) C3-CLUTCH (rotates clockwise) [connects the front planetary carrier and the rear planetary middle sun gear]
(6) Rear planetary middle sun gear (rotates clockwise)
[same revolution as C3-CLUTCH (decelerates by the front planetary gear, so the revolutions are slower than the input shaft)]
(7) Intermediate shaft (rotates clockwise) [same revolution as the input shaft]
(8) C2-CLUTCH (rotates clockwise) [same revolution as the intermediate shaft]
(9) Rear planetary carrier (rotates clockwise) [same revolutions as intermediate shaft]
(10) Rear planetary long pinion gear (rotates clockwise on its axis, orbits clockwise)
[because the rear planetary carrier rotates faster than the rear planetary middle sun gear, the rear planetary middle pinion gear is pushed out by the speed difference, and orbits clockwise while rotating clockwise on its axis.]
(11) Rear planetary ring gear (rotates clockwise)
[because the rear planetary long pinion gear's rotation is added to the rear planetary carrier revolutions, rear planetary ring gear revolution is faster than those of the rear planetary carrier]
(12) Counter drive gear (rotates clockwise)
[because the rear planetary ring gear is installed on the counter drive gear, the rotational direction and revolution is the same as the rear planetary ring gear]
(13) Counter driven gear (rotates counterclockwise)
(14) Differential ring gear (rotates clockwise)
6. "D"-6th gear
Power transmission pathway [Operating components: B1, C2]





(1) Input shaft (rotates clockwise) [same revolution as the torque converter's turbine runner]
(2) Intermediate shaft (rotates clockwise) [same revolution as the torque converter's turbine runner]
(3) B1-BRAKE [locks the rear planetary middle sun gear]
(4) C2-CLUTCH [connects the intermediate shaft and the rear planetary carrier]
(5) Rear planetary carrier (rotates clockwise) [same revolution as the intermediate shaft]
(6) Rear planetary long pinion gear (rotates clockwise on its axis, orbits clockwise)
[because the rear planetary middle sun gear is locked, it is always in a speed increasing condition]
(7) Rear planetary ring gear (rotates clockwise)
[because the rear planetary long pinion gear's rotation is added to the rear planetary carrier revolution, the rear planetary ring gear revolution is faster than those of the rear planetary carrier]
(8) Counter drive gear (rotates clockwise)
[because the rear planetary ring gear is installed on the counter drive gear, the rotational [because the rear planetary ring gear is installed on the counter drive gear, the rotational
(9) Counter driven gear (rotates counterclockwise)
(10) Differential ring gear (rotates clockwise)
7. "R"-Reverse gear
Power transmission pathway [Operating components: C3, B2]





(1) Input shaft (rotates clockwise) [same revolution as the torque converter's turbine runner]
(2) Front planetary ring gear (rotates clockwise) [same revolution as the input shaft]
(3) Front planetary pinion gear (rotates clockwise on its axis, orbits clockwise)
[because the front planetary sun gear is locked by the oil pump, it is pressed against the front planetary ring gear and orbits the sun gear while rotating on its axis (because the front planetary ring gear has internal gears, the rotational direction does not change)]
(4) Front planetary carrier (rotates clockwise)
[reduction: same revolution as the front planetary pinion gear orbit revolution]
(5) C3-CLUTCH (rotates clockwise) [connects the front planetary carrier and the rear planetary middle sun gear]
(6) Rear planetary middle sun gear (rotates clockwise)
[same revolutions as the C3-CLUTCH (rotates slower than the input shaft)]
(7) B2-BRAKE [locks the rear planetary carrier]
(8) Rear planetary long pinion gear (rotates counterclockwise)
(9) Rear planetary ring gear (rotates counterclockwise)
[the rear planetary ring gear is rotated by the rear planetary long pinion gear (because the rear planetary ring gear has internal gears, the rotational direction does not change)]
(10) Counter drive gear (rotates counterclockwise)
[because the rear planetary ring gear is installed on the counter drive gear, the rotational direction and revolution are the same as the rear planetary ring gear]
(11) Counter driven gear (rotates clockwise)
(12) Differential ring gear (rotates counterclockwise)