| Realization of excellent shift quality | Electronic pressure-adjusting control of line pressure by a liner type solenoid (pressure control solenoid A) adopted Electronic control (direct electric shift control) of clutch pressure by duty-cycle type solenoids (shift solenoid A, B, and C, pressure control solenoid B) adopted |
|---|---|
| Superior shift quality | Centrifugal balance clutch chamber adopted |
| High efficiency, compactness, lightweight | Miniature trochoid gear oil pump with torque converter direct drive adopted |
| Improved reliability | Variable resistor type TR switch has been adopted |
| Improved marketability | Sport AT adopted Sub-shifting mechanism has been adopted |
| Improved reliability, reduced noise and vibration | A double arranged gear with a single planetary gear unit is has been adopted as the main shifting mechanism A single planetary gear unit is has been adopted as the sub-shifting mechanism |
AUTOMATIC TRANSAXLE FEATURES
OUTLINE OF OPERATION
- The operation of the electronic automatic transaxle is classified into three systems: the electronic control mechanism, the hydraulic pressure control mechanism, and the powertrain mechanism (includes the torque converter mechanism). The operation of each system is as follows
- Electronic control mechanism According to the signals from the switches and sensors in the input system, the TCM outputs the signal which matches the present driving condition to the linear type solenoid, ON/OFF type solenoids and the duty-cycle type solenoids in the hydraulic pressure control mechanism.
- Hydraulic pressure control mechanism According to the signals from the TCM, each solenoid operates to switch the hydraulic passages in the control valve body and controls the clutch engagement pressure. The line pressure is adjusted by the linear type pressure control solenoid A and duty-cycle type pressure control solenoid B. The hydraulic passages are switched by the ON/OFF type solenoids (shift solenoid D and E.) And the clutch engagement pressure is controlled by the duty-cycle type solenoids (shift solenoid A, B, and C) and ON/OFF type solenoid (shift solenoid F).
- Powertrain mechanism The driving force from the engine is transmitted through the torque converter to the transaxle. Shift solenoid A, B, and C (duty-cycle type), pressure solenoid B (duty-cycle type), shift solenoid F (ON/ OFF type) or clutch engagement pressure control by the control valve enable the transmitted input driving force to be converted to optimum output driving force via the differential.
Scheme 509
Scheme 510
Scheme 511
Component description
| Component | Function |
|---|---|
| Forward clutch | Transmits the input torque from the turbine shaft to the front sun gear. Operates in the forward range of the first, second, or third gear position. |
| 3-4 clutch | Transmits the input torque from the turbine shaft to the rear planetary carrier. Operates in the forward range of the third, fourth or fifth gear position. |
| Reverse clutch | Transmits the input torque from the turbine shaft to the rear sun gear. Operates when the vehicle is backing up. |
| Direct clutch | Engage the secondary planetary carrier and the secondary sun gear. Operates in the fifth gear position. |
| 2-4 brake band | Locks rotation of the reverse drum and fixes the rear sun gear. Operates in the second or fourth gear position. |
| Low and reverse brake | Fixes the rotation of the front internal gear. Operates when the vehicle is backing up or in the first gear position (M range 1GR). |
| Reduction brake | Fixes the rotation of the secondary sun gear. Operates when the vehicle is backing up. Operates in the first, second, third or fourth gear position. |
| One-way clutch No.1 | Locks the counterclockwise rotation of the front internal gear in the first gear position. |
| One-way clutch No.2 | Operates in the first, second, third or fourth gear position. |
| Front planetary gear | The front planetary gear and rear planetary gear functions as a transmission due to the engagement/ disengagement of clutches and/or brakes, converts the transmitted driving force of the turbine shaft and transmits it to the primary gear. |
| Rear planetary gear | |
| Secondary planetary gear | The secondary planetary gear functions as a transmission due to the engagement/ disengagement of clutches and/or brakes, converts the transmitted driving force of the turbine shaft and transmits it to the output gear. |
POWER FLOW OPERATION
Note. All directions of rotation are viewed from the torque converter.
Scheme 512
Scheme 513
Scheme 514
Scheme 515
Scheme 516
Scheme 517
Scheme 518
Scheme 519
Scheme 520
Scheme 521
Scheme 522
Scheme 523
Scheme 524
Scheme 525
2-4 BRAKE BAND OPERATION
- When the hydraulic pressure acts between the servo retainer and the servo piston (2-4 brake band engagement side), the servo piston acts on the 2-4 brake band to lock the 2-4 brake drum. At the same time, the servo return spring also works as resistance to obtain the optimal 2-4 brake band engagement force. When the hydraulic pressure acts between the servo piston and the transaxle case (2-4 brake band release side), the servo piston is pushed to the servo retainer side. This causes the 2-4 brake band to extend by its own spring force and unlock the 2-4 brake drum. When the hydraulic pressure acts between the servo retainer and the servo piston and between the servo piston and the transaxle case simultaneously, the servo piston is pushed to the servo retainer side and the 2-4 brake drum is unlocked because of the difference in the two areas and spring force.
Scheme 526
One-Way Clutch No.1
- The one-way clutch No.1 locks the counterclockwise rotation (seen from the torque converter side) of the front internal gear. The one-way clutch No.1 operates in D, and M range of the 1GR.
One-Way Clutch No.2
- The one-way clutch No.2 locks the clockwise rotation (seen from the torque converter side) of the direct clutch drum. The one-way clutch No.2 operates in D, and M range of the 1GR, 2GR, 3GR and 4GR.
- The one-way clutch outer race is integrated with the front internal gear, and the one-way clutch inner race is fixed to the transaxle case.
- The one-way clutch outer race is integrated with the direct clutch drum, and the one-way clutch inner race is fixed to the transaxle case.
- The one-way clutch outer race (front internal gear) rotates clockwise (seen from the torque converter side) freely, but the springs rise to lock the rotation when the outer race tries to rotate counterclockwise.
- The one-way clutch No.1 locks the counterclockwise rotation of the front internal gear, and also locks the counterclockwise revolution of the rear planetary gear via the rear planetary carrier.
Note. All direction of rotation are viewed from the torque converter.
Scheme 527
- The one-way clutch outer race (direct clutch) rotates counterclockwise (view from torque converter) freely, however, the roller moves to the right (view from torque converter) and locks the rotation when it tries to rotate clockwise.
- One-way clutch No.2 locks the clockwise rotation of the direct clutch, and also locks the clockwise rotation of the secondary sun gear via the direct clutch.
Scheme 528
PARKING MECHANISM OPERATION
- When the selector lever is moved to P position, the manual shaft and the manual plate move in the direction of the arrow A to the position as shown in the figure below. Then the parking rod component moves in the direction of the arrow B, the parking rod component cam pushes up the parking pawl, and the parking pawl engages the parking gear. If the parking pawl hits the tooth of the parking gear, the parking pawl cannot be pushed up, so only the parking rod component is able to move. The cam presses the spring onto the parking pawl and the actuator. If the vehicle runs even a little under this condition, the wheels rotate and parking gear also rotates slightly. As a result, the parking pawl slides into the groove, and engages the parking gear. Thus, the parking mechanism prevents the vehicle from moving in P position.
Scheme 529
OIL PUMP OPERATION
- When the inner rotor in the oil pump rotates, the ATF is drawn to the oil pump and then discharged from the oil pump. The discharge amount is proportional to the rotating speed of the torque converter. The ATF discharge amount is controlled by the pressure regulator valve and the pressure control solenoid.
Scheme 530
SHIFT SOLENOID A, B AND C (DUTY-CYCLE TYPE) OPERATION
Open: When the electrical current does not flow, the supply port (line pressure) in the solenoid opens and is engaged with the output port (clutch pressure). As a result, hydraulic pressure is supplied to the hydraulic passage for the clutch pressure.
Close: When the electrical current flows, the supply port (line pressure) in the solenoid closes and the output port (clutch pressure) and the drain port are engaged to drain the clutch pressure.
Scheme 531
SHIFT SOLENOID D, E AND F (ON/OFF TYPE) OPERATION
On: When the electrical current flows, the output port and the supply port (solenoid reducing pressure or line pressure) are engaged in the solenoid, and the output pressure becomes equivalent to the solenoid reducing pressure.
Off: When the electrical current does not flow, the output port and the drain port are engaged in the solenoid, and the output pressure is drained.
Scheme 532
PRESSURE CONTROL SOLENOID A (LINEAR TYPE) OPERATION
- By changing the electrical current value (0 A-1 A) inside the solenoid, the pressure control solenoid A adjusts the hold power of the hold pressure valve, controlling the pressure control solenoid pressure to the prescribed hydraulic pressure.
Scheme 533
Scheme 534
PRESSURE CONTROL SOLENOID B (DUTY-CYCLE TYPE) OPERATION
1GR to 4 GR or 5GR (Open): When driving in 1GR to 4GR or 5GR, the supply port (line pressure) in the solenoid opens and is engaged with the output port (4-5 duty solenoid pressure). As a result, hydraulic pressure is supplied to the hydraulic passage for the 4-5 duty solenoid.
Shifted from 4GR to 5GR or from 5GR to 4GR (Close): When the gear is shifted from 4GR to 5GR or from 5GR to 4GR, the line pressure is regulated to the optimum hydraulic pressure for the driving condition by energizing for a specified time.
