UNIT 11
SUSPENSION
AND STEERING SYSTEMS
TEXT A
Basic Parts and Types of the Suspension
and Steering Systems
PROFESSIONAL ENGLISH
TEXT A
Basic Parts and Types of the Suspension
and Steering Systems
Basic Suspension System
Components? Types
Steering System
Steering Gear? Power Steering
本次课学习内容本次课学习目标
掌握转向与悬架系统的英文专业词汇
掌握转向与悬架系统主要类型
训练快速阅读能力，提高阅读速度
NEW WORDS
jarring ['d?ɑ:ri?] a.刺耳的
contour ['k?ntu?] n.轮廓，等高线
anchorage ['k?rid?] n.停泊地，抛锚地，固定 (支座 )
unibody ['ju:ni'b?di] n.整体式车身
obsolete ['?bs?li:t] a.荒废的，陈旧的
bump [b?mp] n.凸起，（曲线）拐点，肿块，
撞击
rebound [ri'baund] n,& v.回弹
descend [di'send] v.下来，下降
oscillation [si'lei∫?n] n.摆动，振动，振荡
deplete [di'pli:t] v.耗尽,减少，放空
strut [str?t] n.滑柱，支柱
impose [im'p?uz] v.强加，征税
rest [rest] n.静止，支持物，其余，其他；
v.搁在，保持 (状态 )
soften ['s?(:)fn] v.（使）变柔软,(使 )变柔和
knuckle ['n?kl] n.关节，转向节
pedestal ['pedistl] n.底座，基础
squeak [skwi:k] n.尖叫声，吱吱声； v.发出尖叫声
damper ['d? mp?] n.减振器，缓冲器
confine ['k?nfain] v.限制； n.界限，边界
transverse ['tr? nzv?:s] a.横向的，横断的
parallelogram [?p? r?'lel?gr
m]
n.平行四边形
late-model ['leit'm?dl] a.新型的
bolster ['b?ulst?] v.支持，加强； n.垫子
ease [i:z] n.安逸，不费力； v.使悠闲，减轻
pitman ['pitm?n] n.矿工；连接杆
PHRASES AND EXPRESSIONS
make turns 偏转
steel frame 钢梁车架
leaf spring 叶片弹簧
coil spring 螺旋弹簧
torsion bar 扭杆弹簧
air spring 空气弹簧
ride quality 乘坐舒适性
shock absorber 减振器
curb height 全装备高度
control arm 悬架摆臂
solid axle 整体式车桥
conventional front
suspension
传统式前悬架
Macpherson strut front
suspension
麦弗逊滑柱式前悬架
rubber bumper 橡胶缓冲垫
steering knuckle 转向节
dependent suspension 非独立悬架
dead axle 从动桥，非驱动桥
steering wheel 转向盘
steering gear 转向器
parallelogram linkage 平行四杆机构
rack-and-pinion steering system 齿轮齿条式转向系统
steering shaft 转向轴
manual steering 人力转向
power steering 动力转向
pitman arm 转向摇臂
Basic Parts and Types of the Suspension
and Steering Systems
Suspension System
If a vehicle's axles were bolted directly to its frame or body,
every rough spot in the road would transmit a jarring force
throughout the vehicle,Riding would be uncomfortable,and
handling at freeway speeds would be impossible,The fact that
the modern vehicle rides and handles well is a direct result of
a suspension system.
Even though the tires and wheels must follow the road
contour,the body should be influenced as little as possible [1],
The purpose of any suspension system is to allow the body of
the vehicle to travel forward with a minimum amount of up-
and-down movement,The suspension should also permit the
vehicle to make turns without excessive body roll or tire
skidding.
Suspension System Components
Vehicle Frame
A vehicle's frame or body must form a rigid structural foundation
and provide solid anchorage points for the suspension system,There
are two types of vehicle construction in common use today,body-
over-frame construction,which uses a separate steel frame to which
the body is bolted at various points and unibody construction,in
which the body sections serve as structural members,Unibody
construction is the most common,but body-over-frame construction
is still used on pickup trucks and large cars.
Springs
The springs are the most obvious part of the suspension system,
Every vehicle has a spring of some kind between the frame or body
and the axles,There are three types of springs in general use today,
leaf spring,coil spring,and torsion bar,Two different types of springs
can be used on one vehicle,Air springs were once used in place of
the other types of springs,but are now obsolete,Many modern
vehicles have air-operated suspensions,but they are used to
supplement the springs.
Shock Absorbers
When the vehicle is traveling forward on a level surface and
the wheels strike a bump,the spring is rapidly compressed (coil
springs) or twisted (leaf springs and torsion bars),The spring
will attempt to return to its normal loaded length,In so doing,
it will rebound,causing the body of the vehicle to be lifted,
Since the spring has stored energy,it will rebound past its
normal length,The upward movement of the vehicle also
assists in rebounding past the spring's normal length.
The weight of the vehicle then pushes the spring down after
the spring rebounds,The weight of the vehicle will push the
spring down,but since the vehicle is traveling downward,the
energy built up by the descending body will push the spring
below its normal loaded height,This causes the spring to
rebound again,This process,called spring oscillation,gradually
diminishes until the vehicle is finally still,Spring oscillation can
affect handling and ride quality and must be controlled.
Air Shock Absorbers
Some suspension systems incorporate two adjustable air
shock absorbers that are attached to the rear suspension and
connected to an air valve with flexible tubing.
Air operated shock absorbers have hydraulic dampening
systems which operate in the same manner as those on
conventional shocks,In addition,they contain a sealed air
chamber,which is acted on by pressure from a height control
sensor,Varying the pressure to the air chamber causes the air
shock to increase or decrease its length or operating range.
Air pressure is delivered to the air shocks through plastic
tubing,The tubing connects the shocks to an air valve,Air
pressure for raising the shocks is generally obtained from an
outside source,such as a service station compressor,and is
admitted through the air valve,To deplete the shocks of
unwanted air (lower vehicle curb height),the air valve core is
depressed,allowing air to escape.
Control Arms
All vehicles have either control arms or struts to keep the wheel
assembly in the proper position,The control arms and struts allow
the wheel to move up and down while preventing it from moving in
any other direction,The wheel will tend to move in undesirable
directions whenever the vehicle is accelerated,braked,or turned,
Vehicle suspensions may have control arms only or a combination of
control arms and struts,
Types of the Suspension
Front Suspension Systems
Almost all modern front suspension systems are independent,
With an independent suspension,each front wheel is free to move
up and down with a minimum effect on the other wheel,In an
independent suspension system,there is also far less twisting
motion imposed on the frame than in a system with a solid axle,
Nevertheless,a few off-road,four wheel drive vehicles and large
trucks continue to use a solid axle front suspension,The two major
types of independent front suspension are the conventional front
suspension and the MacPherson strut front suspension.
Conventional Front Suspension In the conventional front
suspension system,one or two control arms are used at each
wheel,In most systems,the coil springs are mounted between the
vehicle's frame and the lower control arm,In older systems,coil
springs are mounted between the upper control arm and vehicle
body,In a torsion bar front suspension system,the lower arm
moves upward,it twists the torsion bar,
Coil Spring Front Suspension Fig.11-1 shows a typical
independent front suspension that uses rubber bushing control
arm pivots,The top of the coil spring rests in a cup-like spot
against the frame (unshown),The bottom of the coil spring is
supported by a pad on the lower control arm,The top of each
shock absorber is fastened to the frame; the bottom is attached to
the lower control arm.
When the wheel strikes a bump,it is driven upward,This
causes arms to pivot upward,compressing the spring and shock,
Rubber bumpers limit control arm travel and soften the blow when
the limit is reached,For steering,the front wheel steering knuckle
pivots on ball joints.
Torsion Bar Front Suspension A torsion bar is located on each
side of the frame in the front of the vehicle,The lower control
arm is attached to the free end of the torsion bar,When the
wheel is driven upward,the lower control arm moves upward,
twisting the long spring steel bar.
Macpherson Strut Front Suspension Most modern vehicles,
especially those with front-wheel drive,use the MacPherson
strut front suspension systems,Fig.11-2,Note that the
MacPherson strut contains a coil spring,which is mounted on
top of the heavy strut-and-pedestal assembly,The entire
MacPherson strut assembly is attached to the steering knuckle
at the lower part of the pedestal,The bottom of the
MacPherson strut assembly is attached to the single control
arm through a ball joint.
Fig,11-1 A typical independent front suspension
Fig.11-2 A MacPherson strut front suspension system
The entire strut assembly turns when the wheel is turned,A
bearing or thrust plate at the top of the strut assembly allows
relative movement between the assembly and the vehicle body,
The ball joint allows the strut assembly to turn in relation to the
control arm,The strut contains a damper,which operates in the
same manner as a conventional shock absorber,Most damper
assemblies have a protective cover that keeps dirt and water
away from the damper piston rod.
The advantage of the MacPherson strut is its compact design,
which allows more room for service on small car bodies,
Solid Axle Front Suspension The use of the solid axle front
suspension (or dependent suspension) is generally confined to
trucks and off-road vehicles,This system uses a solid steel dead
axle (does not turn with wheels) with a leaf spring at each side,
Pivot arrangements between the axle and the wheel spindles
allow the wheels to swivel on each end,Any up or down
movement of either front wheel causes a vertical tipping effect
of both wheels because they share a common axle.
Rear Suspension Systems
Rear suspensions on vehicles with a solid rear axle housing
generally utilize coil springs or leaf springs,When the vehicle
has an independent rear suspension system,coil springs,
MacPherson struts,a single transverse leaf spring,or even
torsion bars can be used.
Steering System
The steering system is designed to allow the driver to move
the front wheels to the right or left with a minimum of effort
and without excessive movement of the steering wheel,
Although the driver can move the wheels easily,road shocks
are not transmitted to the driver,This absence of road shock
transfer is referred to as the nonreversible feature of steering
systems.
The basic steering system can be divided into three main
assemblies:
·The spindle and steering arm assemblies.
·The linkage assembly connecting the steering arms and
steering gear.
·The steering wheel,steering shaft,and steering gear assembly.
Steering Gear
The steering gear is designed to multiply the driver's turning
torque so the front wheels may be turned easily,When the
parallelogram linkage is used,the torque developed by the driver
is multiplied through gears and is then transmitted to the wheel
spindle assemblies through the linkage,On the rack-and-pinion
steering system,the steering shaft is connected directly to the
pinion shaft,Turning the pinion moves the rack section,witch
moves the linkage,Late-model vehicles use either manual steering
gears or power steering gears.
There are three types of the steering gears in use,recirculating
ball steering gear,worm-and-roller steering gear and rack-and-
pinion steering gear.
Power Steering
Power steering is designed to reduce the effort needed to turn
the steering wheel by utilizing hydraulic pressure to bolster
(strengthen) the normal torque developed by the steering gear,
Power steering systems should ease steering wheel
manipulation and,at the same time,offer enough resistance so
that the driver can retain some road feel,Power steering is
used with both conventional and rack-and-pinion systems
(Fig.11-3).
The self-contained steering gear contains the control valve
mechanism,the power piston,and the gears,Pressure
developed by the unit is applied to the pitman shaft.
Fig.11-3 Overall view of a power rack-and pinion
steering assembly
The power rack-and-pinion steering system also uses a
rotary control valve that directs the hydraulic fluid from the
pump to either side of the rack piston,An overall view of
this setup is shown in Figure 11-3,Steering wheel motion
is transferred to the pinion,From there,it is sent through
the pinion teeth,which are in mesh with the rack teeth,
The integral rack piston,which is connected to the rack,
changes hydraulic pressure to a linear force (back and
forth movement in a straight line),This,in turn,moves the
rack in a right or left direction,The force is transmitted by
the inner and outer tie rods to the steering knuckles,which,
in turn,move the wheels.
小结
Basic Braking System and ABS
Basic Suspension System
Suspension System Components
Types of the Suspension
Rear Suspension Systems
Steering System
Steering Gear
Power Steering
作业
熟记相关专业词汇
P247 EXERCIES Ⅰ &Ⅱ
SUSPENSION
AND STEERING SYSTEMS
TEXT A
Basic Parts and Types of the Suspension
and Steering Systems
PROFESSIONAL ENGLISH
TEXT A
Basic Parts and Types of the Suspension
and Steering Systems
Basic Suspension System
Components? Types
Steering System
Steering Gear? Power Steering
本次课学习内容本次课学习目标
掌握转向与悬架系统的英文专业词汇
掌握转向与悬架系统主要类型
训练快速阅读能力，提高阅读速度
NEW WORDS
jarring ['d?ɑ:ri?] a.刺耳的
contour ['k?ntu?] n.轮廓，等高线
anchorage ['k?rid?] n.停泊地，抛锚地，固定 (支座 )
unibody ['ju:ni'b?di] n.整体式车身
obsolete ['?bs?li:t] a.荒废的，陈旧的
bump [b?mp] n.凸起，（曲线）拐点，肿块，
撞击
rebound [ri'baund] n,& v.回弹
descend [di'send] v.下来，下降
oscillation [si'lei∫?n] n.摆动，振动，振荡
deplete [di'pli:t] v.耗尽,减少，放空
strut [str?t] n.滑柱，支柱
impose [im'p?uz] v.强加，征税
rest [rest] n.静止，支持物，其余，其他；
v.搁在，保持 (状态 )
soften ['s?(:)fn] v.（使）变柔软,(使 )变柔和
knuckle ['n?kl] n.关节，转向节
pedestal ['pedistl] n.底座，基础
squeak [skwi:k] n.尖叫声，吱吱声； v.发出尖叫声
damper ['d? mp?] n.减振器，缓冲器
confine ['k?nfain] v.限制； n.界限，边界
transverse ['tr? nzv?:s] a.横向的，横断的
parallelogram [?p? r?'lel?gr
m]
n.平行四边形
late-model ['leit'm?dl] a.新型的
bolster ['b?ulst?] v.支持，加强； n.垫子
ease [i:z] n.安逸，不费力； v.使悠闲，减轻
pitman ['pitm?n] n.矿工；连接杆
PHRASES AND EXPRESSIONS
make turns 偏转
steel frame 钢梁车架
leaf spring 叶片弹簧
coil spring 螺旋弹簧
torsion bar 扭杆弹簧
air spring 空气弹簧
ride quality 乘坐舒适性
shock absorber 减振器
curb height 全装备高度
control arm 悬架摆臂
solid axle 整体式车桥
conventional front
suspension
传统式前悬架
Macpherson strut front
suspension
麦弗逊滑柱式前悬架
rubber bumper 橡胶缓冲垫
steering knuckle 转向节
dependent suspension 非独立悬架
dead axle 从动桥，非驱动桥
steering wheel 转向盘
steering gear 转向器
parallelogram linkage 平行四杆机构
rack-and-pinion steering system 齿轮齿条式转向系统
steering shaft 转向轴
manual steering 人力转向
power steering 动力转向
pitman arm 转向摇臂
Basic Parts and Types of the Suspension
and Steering Systems
Suspension System
If a vehicle's axles were bolted directly to its frame or body,
every rough spot in the road would transmit a jarring force
throughout the vehicle,Riding would be uncomfortable,and
handling at freeway speeds would be impossible,The fact that
the modern vehicle rides and handles well is a direct result of
a suspension system.
Even though the tires and wheels must follow the road
contour,the body should be influenced as little as possible [1],
The purpose of any suspension system is to allow the body of
the vehicle to travel forward with a minimum amount of up-
and-down movement,The suspension should also permit the
vehicle to make turns without excessive body roll or tire
skidding.
Suspension System Components
Vehicle Frame
A vehicle's frame or body must form a rigid structural foundation
and provide solid anchorage points for the suspension system,There
are two types of vehicle construction in common use today,body-
over-frame construction,which uses a separate steel frame to which
the body is bolted at various points and unibody construction,in
which the body sections serve as structural members,Unibody
construction is the most common,but body-over-frame construction
is still used on pickup trucks and large cars.
Springs
The springs are the most obvious part of the suspension system,
Every vehicle has a spring of some kind between the frame or body
and the axles,There are three types of springs in general use today,
leaf spring,coil spring,and torsion bar,Two different types of springs
can be used on one vehicle,Air springs were once used in place of
the other types of springs,but are now obsolete,Many modern
vehicles have air-operated suspensions,but they are used to
supplement the springs.
Shock Absorbers
When the vehicle is traveling forward on a level surface and
the wheels strike a bump,the spring is rapidly compressed (coil
springs) or twisted (leaf springs and torsion bars),The spring
will attempt to return to its normal loaded length,In so doing,
it will rebound,causing the body of the vehicle to be lifted,
Since the spring has stored energy,it will rebound past its
normal length,The upward movement of the vehicle also
assists in rebounding past the spring's normal length.
The weight of the vehicle then pushes the spring down after
the spring rebounds,The weight of the vehicle will push the
spring down,but since the vehicle is traveling downward,the
energy built up by the descending body will push the spring
below its normal loaded height,This causes the spring to
rebound again,This process,called spring oscillation,gradually
diminishes until the vehicle is finally still,Spring oscillation can
affect handling and ride quality and must be controlled.
Air Shock Absorbers
Some suspension systems incorporate two adjustable air
shock absorbers that are attached to the rear suspension and
connected to an air valve with flexible tubing.
Air operated shock absorbers have hydraulic dampening
systems which operate in the same manner as those on
conventional shocks,In addition,they contain a sealed air
chamber,which is acted on by pressure from a height control
sensor,Varying the pressure to the air chamber causes the air
shock to increase or decrease its length or operating range.
Air pressure is delivered to the air shocks through plastic
tubing,The tubing connects the shocks to an air valve,Air
pressure for raising the shocks is generally obtained from an
outside source,such as a service station compressor,and is
admitted through the air valve,To deplete the shocks of
unwanted air (lower vehicle curb height),the air valve core is
depressed,allowing air to escape.
Control Arms
All vehicles have either control arms or struts to keep the wheel
assembly in the proper position,The control arms and struts allow
the wheel to move up and down while preventing it from moving in
any other direction,The wheel will tend to move in undesirable
directions whenever the vehicle is accelerated,braked,or turned,
Vehicle suspensions may have control arms only or a combination of
control arms and struts,
Types of the Suspension
Front Suspension Systems
Almost all modern front suspension systems are independent,
With an independent suspension,each front wheel is free to move
up and down with a minimum effect on the other wheel,In an
independent suspension system,there is also far less twisting
motion imposed on the frame than in a system with a solid axle,
Nevertheless,a few off-road,four wheel drive vehicles and large
trucks continue to use a solid axle front suspension,The two major
types of independent front suspension are the conventional front
suspension and the MacPherson strut front suspension.
Conventional Front Suspension In the conventional front
suspension system,one or two control arms are used at each
wheel,In most systems,the coil springs are mounted between the
vehicle's frame and the lower control arm,In older systems,coil
springs are mounted between the upper control arm and vehicle
body,In a torsion bar front suspension system,the lower arm
moves upward,it twists the torsion bar,
Coil Spring Front Suspension Fig.11-1 shows a typical
independent front suspension that uses rubber bushing control
arm pivots,The top of the coil spring rests in a cup-like spot
against the frame (unshown),The bottom of the coil spring is
supported by a pad on the lower control arm,The top of each
shock absorber is fastened to the frame; the bottom is attached to
the lower control arm.
When the wheel strikes a bump,it is driven upward,This
causes arms to pivot upward,compressing the spring and shock,
Rubber bumpers limit control arm travel and soften the blow when
the limit is reached,For steering,the front wheel steering knuckle
pivots on ball joints.
Torsion Bar Front Suspension A torsion bar is located on each
side of the frame in the front of the vehicle,The lower control
arm is attached to the free end of the torsion bar,When the
wheel is driven upward,the lower control arm moves upward,
twisting the long spring steel bar.
Macpherson Strut Front Suspension Most modern vehicles,
especially those with front-wheel drive,use the MacPherson
strut front suspension systems,Fig.11-2,Note that the
MacPherson strut contains a coil spring,which is mounted on
top of the heavy strut-and-pedestal assembly,The entire
MacPherson strut assembly is attached to the steering knuckle
at the lower part of the pedestal,The bottom of the
MacPherson strut assembly is attached to the single control
arm through a ball joint.
Fig,11-1 A typical independent front suspension
Fig.11-2 A MacPherson strut front suspension system
The entire strut assembly turns when the wheel is turned,A
bearing or thrust plate at the top of the strut assembly allows
relative movement between the assembly and the vehicle body,
The ball joint allows the strut assembly to turn in relation to the
control arm,The strut contains a damper,which operates in the
same manner as a conventional shock absorber,Most damper
assemblies have a protective cover that keeps dirt and water
away from the damper piston rod.
The advantage of the MacPherson strut is its compact design,
which allows more room for service on small car bodies,
Solid Axle Front Suspension The use of the solid axle front
suspension (or dependent suspension) is generally confined to
trucks and off-road vehicles,This system uses a solid steel dead
axle (does not turn with wheels) with a leaf spring at each side,
Pivot arrangements between the axle and the wheel spindles
allow the wheels to swivel on each end,Any up or down
movement of either front wheel causes a vertical tipping effect
of both wheels because they share a common axle.
Rear Suspension Systems
Rear suspensions on vehicles with a solid rear axle housing
generally utilize coil springs or leaf springs,When the vehicle
has an independent rear suspension system,coil springs,
MacPherson struts,a single transverse leaf spring,or even
torsion bars can be used.
Steering System
The steering system is designed to allow the driver to move
the front wheels to the right or left with a minimum of effort
and without excessive movement of the steering wheel,
Although the driver can move the wheels easily,road shocks
are not transmitted to the driver,This absence of road shock
transfer is referred to as the nonreversible feature of steering
systems.
The basic steering system can be divided into three main
assemblies:
·The spindle and steering arm assemblies.
·The linkage assembly connecting the steering arms and
steering gear.
·The steering wheel,steering shaft,and steering gear assembly.
Steering Gear
The steering gear is designed to multiply the driver's turning
torque so the front wheels may be turned easily,When the
parallelogram linkage is used,the torque developed by the driver
is multiplied through gears and is then transmitted to the wheel
spindle assemblies through the linkage,On the rack-and-pinion
steering system,the steering shaft is connected directly to the
pinion shaft,Turning the pinion moves the rack section,witch
moves the linkage,Late-model vehicles use either manual steering
gears or power steering gears.
There are three types of the steering gears in use,recirculating
ball steering gear,worm-and-roller steering gear and rack-and-
pinion steering gear.
Power Steering
Power steering is designed to reduce the effort needed to turn
the steering wheel by utilizing hydraulic pressure to bolster
(strengthen) the normal torque developed by the steering gear,
Power steering systems should ease steering wheel
manipulation and,at the same time,offer enough resistance so
that the driver can retain some road feel,Power steering is
used with both conventional and rack-and-pinion systems
(Fig.11-3).
The self-contained steering gear contains the control valve
mechanism,the power piston,and the gears,Pressure
developed by the unit is applied to the pitman shaft.
Fig.11-3 Overall view of a power rack-and pinion
steering assembly
The power rack-and-pinion steering system also uses a
rotary control valve that directs the hydraulic fluid from the
pump to either side of the rack piston,An overall view of
this setup is shown in Figure 11-3,Steering wheel motion
is transferred to the pinion,From there,it is sent through
the pinion teeth,which are in mesh with the rack teeth,
The integral rack piston,which is connected to the rack,
changes hydraulic pressure to a linear force (back and
forth movement in a straight line),This,in turn,moves the
rack in a right or left direction,The force is transmitted by
the inner and outer tie rods to the steering knuckles,which,
in turn,move the wheels.
小结
Basic Braking System and ABS
Basic Suspension System
Suspension System Components
Types of the Suspension
Rear Suspension Systems
Steering System
Steering Gear
Power Steering
作业
熟记相关专业词汇
P247 EXERCIES Ⅰ &Ⅱ
