你是否想过 当你踩下离合时
Have you, ever wondered what is happening inside a car,
车内部发生了什么
when you press the clutch pedal Or,
又是为什么
why, do you need,
手动挡的车换挡前 需要先踩离合
to press the clutch pedal before you shift gears in a manual transmission car. This
这段视频会向你解释此中逻辑
video gives you, logical answers to these questions
并且在视频最后
At the end of the video we will,
我们将了解在半坡起步时 离合器的重要作用
also understand the crucial role played, by the clutch in an uphill start.
要想理解离合器的作用
To understand the need
先让我们来了解内燃机车辆的构造
for a Clutch let’s first understand the anatomy of an internal combustion engine car
内燃机的扭矩范围有限
Internal combustion engines have a very limited torque band
因此
and due to this reason
为了有效扩大驱动轮的转速范围
in order to efficiently vary the speed of the drive wheels
内燃机车辆需要传动系统
internal combustion engine cars need a transmission system
传动系统的使用确保了发动机在最佳转速范围内工作
The use of this transmission makes sure that the engine is working
并且根据行驶条件的变化
within its optimum rpm range and by changing gear
操纵变速器
According to the driving conditions the
从而控制驱动轮转速
transmission helps to control the drive wheel speeds
手动挡车型换挡并非易事
In a manual transmission car making these gear changes is
为了顺利地手动换挡
not an easy task to have a smooth gear change with a
发动机对传动系统的动力传输必须暂停
Manual transmission the engine power flow to the transmission has to be discontinued
然而 为了换挡使发动机熄火是不实际的
However it is not practical to turn off the engine just for this gear change
这时就该离合器起作用了
The clutch is used for this purpose
简单说 离合器就是在不熄火的前提下
in short the clutch is a mechanism to disconnect the flow
用于断开动力传输的装置
of power to the transmission without turning the engine off
我们来看一下它的工作原理
Let’s understand how it works
离合器的主要部分是一个摩擦片
The main part of the clutch consists of a disc coated
其两面覆盖有高摩擦系数的材料
with high friction material on both sides.
这就是离合器片的简化模型
A simplified clutch disc is shown here.
离合器片装配在飞轮上
This disc sits on the flywheel if
当施加外力把离合器片压在飞轮上时
an external force presses against the clutch disc the clutch disc also will turn
由于摩擦力的作用 离合器片随飞轮转动
with the flywheel due to the frictional force
而传动系统的输入轴与离合器片连接
The input shaft of the transmission is connected to the disc.
所以当外力施加到离合器片上时
So that when an external force is applied to the
发动机动力将被输入到传动系统
disc the engine power will get transmitted to the transmission system
这个外力是由弹簧压盘系统施加的
This external force is provided by a Pressure plate spring system
系统外壳紧紧地固定在飞轮上
Cover of this system is attached firmly to the flywheel
所以压盘会压紧离合器片
So the pressure plate will firmly press
使发动机动力传输到传动系统
onto the friction clutch disc and the engine power will be transmitted to the transmission system
这是正常行驶时的情形
But this is the case
那么离合器是如何实现动力传输中断的呢
in normal driving so how is the power disengagement done with the clutch
为实现动力传输中断
For the disengagement purpose a special kind
压盘装配中用到了一种特殊的弹簧：
of spring is introduced in the pressure plate. Assembly,
膜片弹簧
this spring is known as a diaphragm spring
为了方便理解
To understand this diaphragm spring better,
假设膜片弹簧的固定点为这个圆
assume that the diaphragm spring motion is fixed around the circle.
当中央部分被压下时
In this case, if you press the center portion of the spring as shown
外圈会朝相反方向运动
the outer portion should move in the opposite direction.
膜片弹簧位于压盘和离合器壳之间
The diaphragm spring sits between the pressure plate and the cover
为了更好地理解这个结构 我们来看看装配的局部剖视
To understand this configuration better, let’s take a cross-section of the assembly
膜片弹簧外圈与压盘连接
the outer portion of the diaphragm spring is connected to the pressure disc
所以当中间部分被压下时
This means if you press the inner portion
压盘将远离离合器片
as shown the pressure disc will move away from the friction disk
动力传输因此中断
thus the power flow will discontinue to the transmission
这就是当你踩下离合时 触发的一切
This is exactly what happens when you press the clutch pedal
液压系统把离合器的动作
A hydraulic system transfers the clutch
传递到膜片弹簧中心
motion to the center of the diaphragm spring
膜片弹簧受压时 动力传输中断
When the diaphragm spring is pressed the power flow is discontinued.
此时可以换挡
During this time you can make a gear
挡位切换后 松开离合器踏板
change the clutch pedal is released after the
动力传输就恢复了
gear change and the power flow continues again
此即离合器的工作原理
This is how a clutch works
在离合器上还有一圈螺旋弹簧
In an actual clutch you can see a few coil springs
它们是做什么用的呢
on the clutch disc what’s the purpose of these springs
这些弹簧用于减弱
These are used to smooth out
发动机动力输出的波动和振动
the fluctuations and vibrations from the engine power output
显然
It is clear
轴与离合器片不是刚性连接
that the hub and disc are not directly connected
发动机动力传输至离合器片
The engine power first reaches the disk then
经过弹簧后才至输出轴
it transfers to the springs and finally to the output hub
这意味着
This means that the springs will
这些弹簧将很大程度上减弱发动机动力输出波动
dampen out most of the power flow fluctuations from the engine and the
车辆的驱动也将更平顺
motion transferred to the vehicle will be much smoother Now,
再讨论一下 手动挡车型半坡起步
let’s explore an extremely important and difficult task
这一极重要又具有难度的情形
in driving cars with manual transmission starting from uphill
即使不用手刹 你也可以通过以下踩离合的方式完成半坡起步
Even in a car without a handbrake, you can use this clutch technique to start while pointing uphill.
半坡起步最初 刹车与离合都踩到底
In an uphill start initially both the brake and clutch pedal are pressed,
此时发动机已起动（并挂一挡）
while the engine is running Now,
将离合踏板一点点抬起
release the clutch pedal partially
感觉到接合时定住踏板
until you feel the clutch bite
离合器的接合可以用脚感受
The clutch bite can be experienced at.
这种感受就像发动机在颤抖
Your foot it may feel like the engine is shivering at
此时即使松开刹车
This point even if you release the brake
车也不会后遛
pedal you can see the vehicle will not roll the
半抬起的离合仿佛起到刹车的作用
Partially released clutch acts
此时踩油门 车就会前进了
like a brake now You can press the gas pedal and the car will move forward
那么问题来了 半抬起的离合
The big question here is how
是怎样起到类似刹车的作用的呢
does the partially release clutch act like a break
这其实是个平衡游戏
This break phenomenon is nothing but a game
在完美的受力平衡条件下 车轮无法滚动
of force balanced in a perfectly forced balanced condition the vehicle
重力
Wheels will not be able to roll and the gravitational
将会和车轮的静态摩擦力一样
pull will be the same as static frictional force at the wheels
车轮因为受力平衡而不能滚动
The vehicle wheels are prevented from rolling by another force balance
发动机前进的力和
Force balance between the engine forward
相同的静摩擦力达成受力平衡
force and the same static frictional force
当你半抬离合器 使离合器接合平衡时
When you partially release the clutch and it balances
你在不知不觉中让这些受力平衡了
for the clutch bite you are unknowingly doing all these force balances
当这些受力完美的平衡住车轮
When these forces are in perfect balance the wheels the
传动系统和离合器盘就不可能转动
transmission system and the clutch disk will not be able to spin
这就是离合器然后起到
This is how the clutch bite acts
刹车的作用 但是要记住 接触面间的摩擦力
as a brake but remember the frictional force between the rubbing surfaces
会使发动机牵引力产生 这将会导致
Produces the engine forward force in this case this will result
离合器片上的高摩擦系数材料磨损
in wear and tear of the friction material on the clutch disc
我们希望这个视频可以帮助你们
We hope this video will enable you to
成为一个更好的工程师和更好的司机
be a better engineer and a better driver
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thank you