● 5月 12日 14时 28分，我国四川发生里氏 8级地震
●在地震发生的这一周内,3.4万同胞遇难,22万余人受伤
●国务院已决定：
5月 19日 ~21日为全国哀悼日
5月 19日 14时 28分，全国人民为地震灾区遇难同胞默哀 3分钟
2008年 5月 19日 12时沉痛悼念汶川大地震遇难同胞
UNIT 9
AUTOMATIC TRANSMISSIONS
TEXT A
Automatic Transmission (AT)
PROFESSIONAL ENGLISH
UNIT 8
AUTOMATIC TRANSMISSIONS
TEXT A
Automatic Transmission (AT)
Torque Converter
Planetary Gear
Hydraulic System
Servos and Accumulators
Hydraulic Control System
Electronic Control System
本次课学习内容本次课学习目标
掌握自动变速器的有关英文专业词汇
能够较好地用已知翻译技巧进行课文翻译
训练快速阅读能力，较高的阅读速度
NEW WORDS
impeller [im'pel?] n.推进者，叶轮，泵轮
stator ['steit?] n.定子，导轮
pump [p?mp] n.泵，泵轮
standstill ['st? ndstil] n.停止，停顿
sphere [sfi?] n.球，球体，圈子，半球
flatten ['fl? tn] v.变平，变单调
torus ['t?:r?s] n.圆环面，环形，叶轮,[植 ]花托
sling [sli?] n.投掷，抛
impinge [im'pin?] v.撞击，打击
fashion ['f? ∫?n] n.样子，方式，流行，风尚
servo ['s?:v?u] n.伺服，伺服系统
accumulator [?'kju:mju
leit?]
n.蓄能器，蓄压器，集液器，
[英 ]蓄电池
solenoid ['s?ulin?id] n.[电 ]螺线管
PHRASES AND EXPRESSIONS
drive plate 传动板
planetary gear set 行星齿轮机构
one-way clutch 单向离合器
planetary gearbox
sun gear
行星齿轮变速器太阳轮
planet carrier 行星架
shift valve 换档阀
governor pressure 调速器压力
modulator pressure 调压阀压力
line pressure 主油路压力
Automatic Transmission (AT)
In today's automobile,the automatic transmission is by far
the most complicated mechanical component,It is a type of
transmission that shifts itself,Automatic transmission or
transaxle has four basic systems-a torque converter,a gear
system,a hydraulic system and an electronic system (Fig,9-1),
TORQUE CONVERTER
The torque converter replaces the conventional clutch,It
has three functions:
1,It allows the engine to idle with the vehicle at a standstill,
even with the transmission or transaxle in gear[1].
2,It allows the transmission or transaxle to shift from range-
to-range smoothly,without requiring that the driver close the
throttle during the shift.
3,It multiplies engine torque to an increasing extent as
vehicle speed drops and throttle opening is increased,This has
the effect of making the transmission or transaxle more
responsive and reduces the amount of shifting required.
1,Drive plate 2,Converter lockup clutch 3.Torque converter P,Impeller R,Stator
T,Turbine 4.Clutch A 5,Clutch B 6,Clutch C' 7,Clutch C 8,Clutch D 9,Planetary
gear set 10,Planetary gear set,fourth gear 11,Clutch E 12,Clutch F 13,Output
14-17,One-way clutch
Fig,9-1 Components of a typical automatic transmission
The torque converter is a metal case which is shaped like a
sphere that has been flattened on opposite sides,it is bolted to the
rear end of the engine's crankshaft,Generally,the entire metal case
rotates at engine speed and serves as the engine's flywheel.
The case contains three sets of blades (Fig.9-2),One set is
attached directly to the case,This set forms the torus or pump,
Another set is directly connected to the output shaft,and forms the
turbine,The third set is mounted on a hub which,in turn,is
mounted on a stationary shaft through a one-way clutch,This third
set is known as the stator.
A pump,which is driven by the converter hub at engine speed,
keeps the torque converter full of automatic transmission fluid at all
times,Fluid flows continuously through the unit to provide cooling.
Under low speed acceleration,the torque converter functions as
follows:
The torus is turning faster than the turbine,It picks up fluid at
the center of the converter and,through centrifugal force,slings it
outward,Since the outer edge of the converter moves faster than
the portions at the center,the fluid picks up speed.
Fig,9-2 The torque
converter housing is
rotated by the
engine's crankshaft,
and turns the impeller,
The impeller then
spins the turbine,
which gives motion to
the turbine shaft,
driving the gears
The fluid then enters the outer edge of the turbine blades; it
then travels back toward the center of the converter case
along the turbine blades,In impinging upon the turbine
blades,the fluid loses the energy picked up in the torus.
If the fluid was now returned directly into the torus,both
halves of the converter would have to turn at approximately the
same speed at all times,and torque input and output would both
be the same.
In flowing through the torus and turbine,the fluid picks up two
types of flow,or flow in two separate directions,It flows through
the turbine blades,and it spins with the engine,The stator,whose
blades are stationary when the vehicle is being accelerated at low
speeds,converts one type of flow into another [2],Instead of
allowing the fluid to flow straight back into the torus,the stator's
curved blades turn the fluid almost 90° toward the direction of
rotation of the engine,Thus the fluid does not flow as fast toward
the torus,but is already spinning when the torus picks it up,This
has the effect of allowing the torus to turn much faster than the
turbine,This difference in speed may be compared to the
difference in speed between the smaller and larger gears in any
gear train,The result is that engine power output is higher,and
engine torque is multiplied.
As the speed of the turbine increases,the fluid spins
faster and faster in the direction of engine rotation,As a
result,the ability of the stator to redirect the fluid flow is
reduced,Under cruising conditions,the stator is eventually
forced to rotate on its one-way clutch in the direction of
engine rotation,Under these conditions,the torque converter
begins to behave almost like a solid shaft,with the torus and
turbine speeds being almost equal.
PLANETARY GEAR
The ability of the torque converter to multiply engine
torque is limited,Also,the unit tends to be more efficient
when the turbine is rotating at relatively high speeds,
Therefore,a planetary gearbox is used to carry the power
output of the turbine to the driveshaft.
Planetary gears function very similarly to conventional
transmission gears,However,their construction is different
in that three elements make up one gear system,and,in
that all three elements are different from one another [3].
The three elements are,an outer gear that is shaped like a
hoop,with teeth cut into the inner surface; a sun gear,
mounted on a shaft and located at the very center of the outer
gear; and a set of four planet gears,held by pins in a ring-like
planet carrier,meshing with both the sun gear and the outer
gear （ Fig.9-3）,Either the outer gear or the sun gear may be
held stationary,providing more than one possible torque
multiplication factor for each set of gears,Also,if all three
gears are forced to rotate at the same speed,the gear set
forms,in effect,a solid shaft.
Most automatics use the planetary gears to provide various
reductions ratios,Bands and clutches are used to hold various
portions of the gear sets to the transmission case or transaxle
case or to the shaft on which they are mounted [4],Shifting is
accomplished,then,by changing the portion of each planetary
gear set which is held to the case or to the shaft.
Fig,9-3 Planetary gears work
in a similar fashion to manual
transmission gears,but are
composed of three parts
HYDRAULIC
SYSTEM
Servos and
Accumulators
The servos（ Fig.9-4）
are hydraulic pistons
and cylinders,They
resemble the hydraulic
actuators used on
many other machines,
such as bulldozers,
Hydraulic fluid enters
the cylinder,under
pressure,and forces
the piston to move to
engage the band or
clutches.
Fig.9-4 Servos,operated by
pressure,are used to apply
or release the bands,to
either hold the ring gear or
allow it to rotate
The accumulators are used to
cushion the engagement of
the servos,The automatic
transmission or transaxle fluid
(ATF) must pass through the
accumulator on the way to the
servo,The accumulator
housing contains a thin piston
which is sprung away from the
discharge passage of the
accumulator,When fluid
passes through the
accumulator on the way to the
servo,it must move the piston
against spring pressure,and
this action smoothes out the
action of the servo.
Hydraulic Control System
The hydraulic pressure used to operate the servos comes from
the main oil pump,This fluid is channeled to the various servos
through the shift valves,There is generally a manual shift valve
which is operated by the selector lever and an automatic shift
valve for each automatic upshift the transmission or transaxle
provides,
There are two pressures which affect the operation of these
valves,One is the governor pressure which is affected by vehicle
speed,The other is the modulator pressure which is affected by
intake manifold vacuum or throttle position,Governor pressure
rises with an increase in vehicle speed,and modulator pressure
rises as the throttle is opened wider,By responding to these two
pressures,the shift valves cause the upshift points to be delayed
with increased throttle opening to make the best use of the
engine's power output.
The modulator also governs the line pressure,used to actuate
the servos,In this way,the clutches and bands will be actuated
with a force matching the torque output of the engine.
Electronic Control System
Many new transmission or transaxles are electronically
controlled (Fig.9-5),On these units,electrical solenoids are
used to better control the hydraulic fluid,Usually,the solenoids
are regulated by an electronic control module.
On modern cars,the line pressure,converter lockup,shift
point and shift quality are all controlled by an electronic control
unit.
Fig,9-5 An electronic transmission control system
小结
Automatic Transmission (AT)
Torque Converter
Planetary Gear
Hydraulic System
Servos and Accumulators
Hydraulic Control System
Electronic Control System
作业熟记相关专业词汇
P211 EXERCIES Ⅰ &Ⅱ
●在地震发生的这一周内,3.4万同胞遇难,22万余人受伤
●国务院已决定：
5月 19日 ~21日为全国哀悼日
5月 19日 14时 28分，全国人民为地震灾区遇难同胞默哀 3分钟
2008年 5月 19日 12时沉痛悼念汶川大地震遇难同胞
UNIT 9
AUTOMATIC TRANSMISSIONS
TEXT A
Automatic Transmission (AT)
PROFESSIONAL ENGLISH
UNIT 8
AUTOMATIC TRANSMISSIONS
TEXT A
Automatic Transmission (AT)
Torque Converter
Planetary Gear
Hydraulic System
Servos and Accumulators
Hydraulic Control System
Electronic Control System
本次课学习内容本次课学习目标
掌握自动变速器的有关英文专业词汇
能够较好地用已知翻译技巧进行课文翻译
训练快速阅读能力，较高的阅读速度
NEW WORDS
impeller [im'pel?] n.推进者，叶轮，泵轮
stator ['steit?] n.定子，导轮
pump [p?mp] n.泵，泵轮
standstill ['st? ndstil] n.停止，停顿
sphere [sfi?] n.球，球体，圈子，半球
flatten ['fl? tn] v.变平，变单调
torus ['t?:r?s] n.圆环面，环形，叶轮,[植 ]花托
sling [sli?] n.投掷，抛
impinge [im'pin?] v.撞击，打击
fashion ['f? ∫?n] n.样子，方式，流行，风尚
servo ['s?:v?u] n.伺服，伺服系统
accumulator [?'kju:mju
leit?]
n.蓄能器，蓄压器，集液器，
[英 ]蓄电池
solenoid ['s?ulin?id] n.[电 ]螺线管
PHRASES AND EXPRESSIONS
drive plate 传动板
planetary gear set 行星齿轮机构
one-way clutch 单向离合器
planetary gearbox
sun gear
行星齿轮变速器太阳轮
planet carrier 行星架
shift valve 换档阀
governor pressure 调速器压力
modulator pressure 调压阀压力
line pressure 主油路压力
Automatic Transmission (AT)
In today's automobile,the automatic transmission is by far
the most complicated mechanical component,It is a type of
transmission that shifts itself,Automatic transmission or
transaxle has four basic systems-a torque converter,a gear
system,a hydraulic system and an electronic system (Fig,9-1),
TORQUE CONVERTER
The torque converter replaces the conventional clutch,It
has three functions:
1,It allows the engine to idle with the vehicle at a standstill,
even with the transmission or transaxle in gear[1].
2,It allows the transmission or transaxle to shift from range-
to-range smoothly,without requiring that the driver close the
throttle during the shift.
3,It multiplies engine torque to an increasing extent as
vehicle speed drops and throttle opening is increased,This has
the effect of making the transmission or transaxle more
responsive and reduces the amount of shifting required.
1,Drive plate 2,Converter lockup clutch 3.Torque converter P,Impeller R,Stator
T,Turbine 4.Clutch A 5,Clutch B 6,Clutch C' 7,Clutch C 8,Clutch D 9,Planetary
gear set 10,Planetary gear set,fourth gear 11,Clutch E 12,Clutch F 13,Output
14-17,One-way clutch
Fig,9-1 Components of a typical automatic transmission
The torque converter is a metal case which is shaped like a
sphere that has been flattened on opposite sides,it is bolted to the
rear end of the engine's crankshaft,Generally,the entire metal case
rotates at engine speed and serves as the engine's flywheel.
The case contains three sets of blades (Fig.9-2),One set is
attached directly to the case,This set forms the torus or pump,
Another set is directly connected to the output shaft,and forms the
turbine,The third set is mounted on a hub which,in turn,is
mounted on a stationary shaft through a one-way clutch,This third
set is known as the stator.
A pump,which is driven by the converter hub at engine speed,
keeps the torque converter full of automatic transmission fluid at all
times,Fluid flows continuously through the unit to provide cooling.
Under low speed acceleration,the torque converter functions as
follows:
The torus is turning faster than the turbine,It picks up fluid at
the center of the converter and,through centrifugal force,slings it
outward,Since the outer edge of the converter moves faster than
the portions at the center,the fluid picks up speed.
Fig,9-2 The torque
converter housing is
rotated by the
engine's crankshaft,
and turns the impeller,
The impeller then
spins the turbine,
which gives motion to
the turbine shaft,
driving the gears
The fluid then enters the outer edge of the turbine blades; it
then travels back toward the center of the converter case
along the turbine blades,In impinging upon the turbine
blades,the fluid loses the energy picked up in the torus.
If the fluid was now returned directly into the torus,both
halves of the converter would have to turn at approximately the
same speed at all times,and torque input and output would both
be the same.
In flowing through the torus and turbine,the fluid picks up two
types of flow,or flow in two separate directions,It flows through
the turbine blades,and it spins with the engine,The stator,whose
blades are stationary when the vehicle is being accelerated at low
speeds,converts one type of flow into another [2],Instead of
allowing the fluid to flow straight back into the torus,the stator's
curved blades turn the fluid almost 90° toward the direction of
rotation of the engine,Thus the fluid does not flow as fast toward
the torus,but is already spinning when the torus picks it up,This
has the effect of allowing the torus to turn much faster than the
turbine,This difference in speed may be compared to the
difference in speed between the smaller and larger gears in any
gear train,The result is that engine power output is higher,and
engine torque is multiplied.
As the speed of the turbine increases,the fluid spins
faster and faster in the direction of engine rotation,As a
result,the ability of the stator to redirect the fluid flow is
reduced,Under cruising conditions,the stator is eventually
forced to rotate on its one-way clutch in the direction of
engine rotation,Under these conditions,the torque converter
begins to behave almost like a solid shaft,with the torus and
turbine speeds being almost equal.
PLANETARY GEAR
The ability of the torque converter to multiply engine
torque is limited,Also,the unit tends to be more efficient
when the turbine is rotating at relatively high speeds,
Therefore,a planetary gearbox is used to carry the power
output of the turbine to the driveshaft.
Planetary gears function very similarly to conventional
transmission gears,However,their construction is different
in that three elements make up one gear system,and,in
that all three elements are different from one another [3].
The three elements are,an outer gear that is shaped like a
hoop,with teeth cut into the inner surface; a sun gear,
mounted on a shaft and located at the very center of the outer
gear; and a set of four planet gears,held by pins in a ring-like
planet carrier,meshing with both the sun gear and the outer
gear （ Fig.9-3）,Either the outer gear or the sun gear may be
held stationary,providing more than one possible torque
multiplication factor for each set of gears,Also,if all three
gears are forced to rotate at the same speed,the gear set
forms,in effect,a solid shaft.
Most automatics use the planetary gears to provide various
reductions ratios,Bands and clutches are used to hold various
portions of the gear sets to the transmission case or transaxle
case or to the shaft on which they are mounted [4],Shifting is
accomplished,then,by changing the portion of each planetary
gear set which is held to the case or to the shaft.
Fig,9-3 Planetary gears work
in a similar fashion to manual
transmission gears,but are
composed of three parts
HYDRAULIC
SYSTEM
Servos and
Accumulators
The servos（ Fig.9-4）
are hydraulic pistons
and cylinders,They
resemble the hydraulic
actuators used on
many other machines,
such as bulldozers,
Hydraulic fluid enters
the cylinder,under
pressure,and forces
the piston to move to
engage the band or
clutches.
Fig.9-4 Servos,operated by
pressure,are used to apply
or release the bands,to
either hold the ring gear or
allow it to rotate
The accumulators are used to
cushion the engagement of
the servos,The automatic
transmission or transaxle fluid
(ATF) must pass through the
accumulator on the way to the
servo,The accumulator
housing contains a thin piston
which is sprung away from the
discharge passage of the
accumulator,When fluid
passes through the
accumulator on the way to the
servo,it must move the piston
against spring pressure,and
this action smoothes out the
action of the servo.
Hydraulic Control System
The hydraulic pressure used to operate the servos comes from
the main oil pump,This fluid is channeled to the various servos
through the shift valves,There is generally a manual shift valve
which is operated by the selector lever and an automatic shift
valve for each automatic upshift the transmission or transaxle
provides,
There are two pressures which affect the operation of these
valves,One is the governor pressure which is affected by vehicle
speed,The other is the modulator pressure which is affected by
intake manifold vacuum or throttle position,Governor pressure
rises with an increase in vehicle speed,and modulator pressure
rises as the throttle is opened wider,By responding to these two
pressures,the shift valves cause the upshift points to be delayed
with increased throttle opening to make the best use of the
engine's power output.
The modulator also governs the line pressure,used to actuate
the servos,In this way,the clutches and bands will be actuated
with a force matching the torque output of the engine.
Electronic Control System
Many new transmission or transaxles are electronically
controlled (Fig.9-5),On these units,electrical solenoids are
used to better control the hydraulic fluid,Usually,the solenoids
are regulated by an electronic control module.
On modern cars,the line pressure,converter lockup,shift
point and shift quality are all controlled by an electronic control
unit.
Fig,9-5 An electronic transmission control system
小结
Automatic Transmission (AT)
Torque Converter
Planetary Gear
Hydraulic System
Servos and Accumulators
Hydraulic Control System
Electronic Control System
作业熟记相关专业词汇
P211 EXERCIES Ⅰ &Ⅱ
