Automatic transmission-23
Figure 4.1 Power flow chart
Torque converter
The torque converter (refer to Figure 4.2) consists of the turbine, stator, impeller and a lock throttle brake and piston assembly.
Same as that of the traditional torque converter, the impeller is connected to the end cover of the torque converter. The turbine is
connected to the input shaft through the spline. The stator is installed on the pump housing through the one-way clutch .
Figure 4.2 Section of torque converter
The buffer and piston assembly can make the torque converter is locked in proper condition. The locking action only occurs
in the condition of specified throttle position opening and vehicle speed. When the hydraulic force makes the buffer and piston
assembly is coupled on the cover of torque converter, it can acquire the locking status. In this status, it can eliminate the
unnecessary sliding. It can increase the economical efficiency of fuel oil when the locking action is generated. When in locking
status, the torque buffer spring in the buffer and piston can absorb the torque fluctuation of engine
.
Clutch assembly
It has four types of clutch assembly (refer to Figure 4.3). All clutch assemblies are composed of several layers of steel plate and
friction disk.
Clutch C1 When it is engaged, the drive shaft drive the planet carrier. The condition occurs in 3
rd and 4th Gear.
Clutch C2 When it is engaged, the drive shaft drive the forward central gear through the 3-4 one-way clutch. The conditio
occurs in 1
st, 2nd and 3rd-Gear condition.
Clutch C3 When it is engaged, the drive shaft drive the backward central gear. The condition occurs in R-Gear position.
Clutch C4 It can provide the brake of engine during overspeed when is engaged, The condition occurs in manual 1
st, 2nd and 3rd
–Gear, also in automatic 2nd and 3rd-Gear to avoid the unfavorable inertia rotation of freewheel.
Automatic transmission-24
Front servo and brake belt Rear servo and brake belt
Figure 4.4 brake belt
One-way clutch
The transmission has two one-way clutches, 1-2 one-way clutch and 3-4 one-way clutch (notice that the third one-way clutch is
located on torque converter, also called as retainer)
1-2 one-way clutch is located between the planet carrier assembly and central shaft. The structure makes the planet carrier only
can rotate in single direction around the central shaft. The one-way clutch is only engaged in automatic 1
st-Gear.
3-4 one-way clutch is located between the clutch C4 and clutch C2.The structure makes the clutch C2 drive the front planetary
gear in 1
st, 2nd and 3rd –Gear, but is disengaged in 4th-Gear and overspeed.
Planetary gear assembly
The planetary gear block used in transmission is the traditional lavena gear block consisted of6 pinions.
Parking mechanism
When select the parking-Gear, the steering column will move the parking lever backwardly to engage with the parking ratch
(refer to Figure 4.5). The ratchet is engaged with the tooth of external gear ring fear to lock the output shaft axle in the
transmission. When it is not in parking-gear, the return spring will release the parking ratchet and unlock the output shaft to
prevent the occurrence of accident parking action.
Figure 4.3 Clutch assembly
Brake belt
The transmission has two brake belts, brake belt B1 (named as 2-4 brake belt sometimes ) and brake belt B2 (named as low-speed
– reverse gear brake belt ) refer to Figure 4.4.
The brake belt B1 is a flexible brake belt which is engaged with front servo piston. When it is in 2
nd and 4th –Gear, the brake belt
B1 starts to act. When the brake belt acts, it can prevent the rotation of reverse central gear by maintaining the clutch C3 assembly
is in static. In 2
nd –Gear, only the external surface of piston is used. In 4thGear, both sides are used to acquire more clamping force.
The brake belt B2 is a solid brake belt which is meshed with the rear servo piston. When the B2 acts, it prevents the rotation of
planet carrier assembly. When in manual 1
st-Gear, only the external surface of piston is used. In reverse-Gear, both sides are used
to acquire more clamping force.
Automatic transmission-26
Power transmission
Introduction
It has the following power transmission pointed to different Gear-position:
power transmission N-Gear and P-Gear
power transmission R-Gear
power transmission manual 1
power transmission Automatic 1st-Gear
power transmission Automatic 2nd -Gear
power transmission Automatic 3rd -Gear
power transmission Automatic 3rd-Gear locking
power transmission Automatic 4th -Gear (overspeed -gear)
power transmission Automatic 4th -Gear locking
For description of each kind of power transmission condition, refer to following parts.
Table 5.1 describe the on-off condition of each unit in all gear condition.
Name of participated unit
Position C1 C2 C3 C4 B1 B2 1-2
OWC 3-4
OWC LU
clutch
Parking and neutral position - - - - - X - - -
Reverse - - X - X - - -
Manual 1st -G ear - X - X - X - X
Automatic 1st- Gear - X - - - - X -
Auto 2nd-Gear and manual
2nd -G ear - X - X X - - X - Automatic 3rd –Gear and
manual 3rd-Gear X X - X - - - X - Automatic 3rd-Gear locking
and manual 3rd-Gear
locking X X - X - - - X X
Automatic 4th -Gear
(overspeed -gear) X X - - X - - - -
Automatic 4th -Gear locking
X X - - X - - - X
In P-Gear or N-Gear, the planetary gear assembly has not the drive. The rear brake belt is used to eliminate the voice generated in
engagement with reverse gear and increase the application of 4WD. It is without the engagement of clutch and brake belt.
In parking-Gear, the locking of mechanism is realized through the engagement of brake lever installed on housing and tooth of
output shaft gear ring.
Control
In stabl
e status, to maintain the arrangement, the status of solenoid valve and valve is shown as follows:
solenoid valve S1 and S2 is powered off.
The line (pump) pressure is applied on the primary regulating valve (PRV) and electromagnetic supply valve.
The torque converter, oil cooler and lubrication loop are filled up with the transmission fluid from the primary regulating
valve.
The line pressure 500 loop is filled up with the transmission fluid from the electromagnetic supply valve.
S5 will be filled up with the transmission fluid through the variable pressure
egulating valve (S5) .
The line pressure is prohibited form entering into the drive loop through the manual-operated valve .
B1 loop and all clutch loop are opened to drainage port.
Automatic transmission-29
In reverse-Gear position, the drive of transmission is sent to the clutch hub through the input shaft and rear clutch piston. In this
condition, the description of each function unit of transmission is shown as follows:
The clutch C3 is engaged and drive the reverse central gear to rotate in clockwise.
The engagement of B2 brake belt cause the rest of the planetary gear carrier, then make the long planetary gear rotates
around its shaft anticlockwise.
The long planetary gear drives the internal gear ring rotates anticlockwise .
Use the spline to connect the inner gear ring to the output shaft and drive the gear ring rotate anticlockwise or in reverse.
Control:
In stable status, to maintain the arrangement, the action of solenoid valve and valve is shown as follows:
A solenoid valve S1 or S2 is closed at least. (Refer to the part in section 3.3.11, related to condition when S1 and S2 is
closed.)
The line pressure reaches the internal surface and external surface of rear servo piston through the reverse lock valve
directly.
The line pressure urges the reverse-Gear loop oil pass through the manual-operated valve.
The reverse-Gear loop oil is circuited to clutch C3 through the manual-operated valve.
In the transmission whiteout HP pump shell, the reverse-Gear loop also can reaches the spring end of the primary
regulating valve to support the spring and push the line-pressure regulating valve.
The oil loop of execution line of all other clutches and brake belts is opened to leaking port.
Refer to Figure 5.2 and Table 5.3.
Table 5.3 The participating condition of each unit in reverse-Gear position
Gear-position
Reverse gear
Name of participated unit
Automatic transmission-31
Power transmission manual 1st-Gear
In manual 1st –Gear, the drive of transmission is send to the rear clutch cylinder through the input shaft. In this
condition, each function unit of transmission is shown as follows:
The clutch C2 is engaged through the 3-4 one-way clutch (OWC) to drive the front sun gear.
The engagement of B2 brake belt make the planetary gear carrier to stop.
The front sun gear drive the short planetary gear to rotate in anticlockwise.
The short planetary gear drive the long planetary gear to rotate in clockwise.
The long planetary gear rotate around its axial to drive the internal gear ring and output
shaft to rotate in clockwise to realize the movement in forward direction.
In overspeed, clutch C4 can provides certain brake force through 3-4 one-way clutch .
Control:
In stable status, the action of solenoid valve and valve is shown as follows:
The solenoid valve S1 and S2 is powered on.
In the action of pressure of line 500, the gear shift valve of 1-2, 2-3, 3-4 gear are kept in position of 1st-Gear.
The manual-operated valve transmission fluid (line pressure ) makes the clutch C2 to engagement.
LO-1st (line pressure) oil flows to the clutch C4 through the 1-2 Gear switching valve to engage the B2 brake belt.
Refer to Figure 5.3 and Table 5.4.
Table 5.4
The participating condition of each unit in manual 1st-Gear
Name of participated unit
X X
Automatic transmission-33
Power transmission automatic 1st-Gear
In automatic 1st -Gear, the drive of transmission reaches the reaches the front clutch cylinder through the input shaft.
In this condition, the operating principle of each function unit of transmission is shown as follows:
The engagement of clutch C2 drives the front sun gear
The front sun gear drive the short planetary gear to rotate in anticlockwise.
The short planetary gear drives the long planetary gear to rotates in clockwise.
1-2 one-way clutch (OWC) stops the rotation of planetary gear carrier in counteracting force. At the same time, the long
planetary gear rotates around its axial to drive the ring gear and output shaft to rotate in clockwise to realize the forward
movement.
Control:
In stable status, the status of solenoid valve and valve is shown as follows:
Solenoid valve S1and S2 is powered on
In the action of line 500 pressure, the gear shift valve of 1-2, 2-3, 3-4 Gear is maintained in 1st-gear position.
The transmission drive oil (line pressure) from the manual-operated valve makes the engagement of clutch C2.
Table 5.5—participating condition of each unit in automatic 1st-Gear
Name of participation unit
Gear position
Automatic 1st-Gear
Refer to Figure 5.4and Table 5.5.
Automatic transmission-35
Power transmission automatic 2nd-Gear and manual 2
In automatic 1st and manual 2nd-Gear, the drive of transmission reaches the front clutch cylinder through the input shaft. In this
condition, the operating principle of each functional unit of transmission is shown as follows:
The engagement of clutch C2 drives the forward central gear.
The forward central gear drives the short planetary gear to rotate in anticlockwise.
The short planetary gear drives the long planetary gear to rotate clockwise.
The engagement of brake belt B1 makes the stop of reverse central gear to make the long planetary gear rotates around the
reverse central gear, then make the internal gear and output shaft rotates in clockwise to make the vehicle moves forwardly.
The clutch C4 is engaged through the 3-4 one-way clutch (OWC) and provides the brake force of engine during overspeed.
Control:
In stable status, the status action of solenoid valve and valve is shown as follows:
The solenoid valve S1 is powered off ; The solenoid valve S2 is powered on.
The drive oil (line pressure) from the manual-operated valve makes the engagement of clutch C2.
When the solenoid valve S1 is powered off, the S1 oil pressure form line pressure 500 pushes the 3-4 Gear shifting valve
moves to left. At the same time, the S1 oil flows into the 1-2 Gear shifting valve to push the 1-2 Gear shifting valve to the
2
nd –Gear.
The line pressure oil from the 1-2 Gear shifting valve flows into the brake belt combination regulating valve, and 2-3 Gar
shifting valve.
The brake belt engagement regulator valve provides the 2nd-Gear oil (controlled by product of line pressure and valve rate)
to brake belt feed loop (BAF).
The brake belt engagement feed loop directly provides the oil to:
External engagement part of front servo piston.
1-2 Gear shifting valve can provide a oil drainage port when the transmission is shifted to 1st-Gear.
Use the 3-4 Gear shifting valve when the transmission is in 4
th-Gear position.
The drive force (line pressure) is sent to the clutch C4 through the 3-4 Gear shifting valve to realize the engagement of
clutch C4.
Refer to Figure 5.5 and table 5.6
Table 5.6The participating condition of each unit in automatic 2nd-Gear and manual 2nd-Gear
Automatic 2nd-Gear and manual
2
nd-Gear
Name of participation unit
Automatic transmission-36
Figure 5.5 Automatic 2
nd-Gear
manual 2
nd-Gear