What does a clutch do?

For manual transmission models, the clutch is an important part of the automotive power system, which is responsible for cutting off and connecting the power and the engine. When driving on urban roads or complex road sections, the clutch has become one of the most frequently used components, and the quality of the clutch directly reflects the level of driving and also plays a role in protecting the vehicle. How to use the clutch correctly and master the principle of the clutch to use the clutch to solve problems in special situations is what every driver of a manual transmission model should master.

The so-called clutch, as the name suggests, is to use "off" and "close" to transmit the right amount of power. The clutch is composed of friction plates, spring plates, pressure plates and power take-off shafts, which are located between the engine and the gearbox, and are used to transmit the torque stored on the engine flywheel to the gearbox to ensure that the vehicle transmits the appropriate amount of driving force and torque to the driving wheels under different driving conditions, which belongs to the category of powertrain. In the case of semi-linkage, the power input end of the clutch and the power output end are allowed to have a speed difference, that is, the appropriate amount of power is transmitted through its speed difference.

What are the uses of clutches in automobiles?

The engagement and disengagement of the clutch are controlled by the on/off power of the coil. Electromagnetic clutches can be divided into: dry single-plate electromagnetic clutch, dry multi-plate electromagnetic clutch, wet multi-plate electromagnetic clutch, magnetic particle clutch, differential electromagnetic clutch, etc.

The working mode of electromagnetic clutch can be divided into: energized combination and power-off combination. Dry monoplate electromagnetic clutch:

When the coil is energized, a magnetic force is generated to attract the "armature" plate, and the clutch is in an engaged state; When the coil is de-energized, the "armature" springs back and the clutch is in a disengaged state. Dry multi-plate, wet multi-plate electromagnetic clutch: the principle is the same as above, in addition to adding a few friction payments, the same volume torque is larger than the dry single-plate electromagnetic clutch, wet multi-plate electromagnetic clutch must be cooled by oil or other coolant when working.

Clutch magnetic powder clutch, between the active and driven parts placed magnetic, when not energized, the magnetic powder is in a loose state, when energized magnetic powder combined, the active parts and the driven parts rotate at the same time. Advantages: The torque can be adjusted by adjusting the current, allowing for large slippage.

Disadvantages: The temperature rise is larger when the slippage is larger, and it is relatively high. Differential electromagnetic clutch:

When the clutch is working, there must be a certain speed difference between the master and slave parts to have torque transmission. The magnitude of the torque depends on the strength of the magnetic field and the difference in rotational speed. The excitation current remains the same, and the speed decreases sharply with the increase of torque; The torque remains the same, the excitation current decreases, and the rotational speed decreases even more.

The clutch is an important part of the automotive power system, which is responsible for cutting off and connecting the power and the engine. The clutch needs to be pressed when the vehicle starts, shifts gears, and stops in neutral.

The role of the clutch:

1. Ensure a smooth start of the car.

This is the primary function of the clutch. Before the car starts, it is natural to start the engine first. Whereas, when the car starts, the car accelerates gradually from a completely stationary state.

If the drivetrain (which links the entire car) is rigidly connected to the engine, the car will suddenly move forward as soon as the transmission is engaged.

Rush, but not start. This is because the car has a lot of inertia when it goes from stationary to forward, which causes a lot of drag torque to the engine. Under the action of this inertial drag torque, the engine speed drops sharply to below the minimum stable speed (generally 300-500rpm) in an instantaneous time, and the engine stops and cannot work, and of course, the car cannot start.

Therefore, the help of the clutch is needed. After the engine starts, before the car starts, the driver first presses the clutch pedal, disengages the clutch, disengages the engine and the drive train, and then puts the transmission into gear, and then gradually releases the clutch pedal to make the clutch gradually engaged. In the process of engagement, the drag torque of the engine gradually increases, so the accelerator pedal should be gradually pressed at the same time, that is, the fuel supply to the engine should be gradually increased, so that the speed of the engine is always maintained at the lowest stable speed without stalling.

At the same time, as the engagement of the clutch gradually increases, the torque transmitted by the engine to the driving wheels through the drive train gradually increases, and when the traction force is sufficient to overcome the starting resistance, the car starts to move from a standstill and accelerates gradually.

2. Achieve smooth gear shifting.

In the process of driving, in order to adapt to the changing driving conditions, the drive train often has to change different gears to work. To realize the gear shift of the gear transmission, it is generally to toggle the gear or other gear mechanism, so that a gear pair of the original gear is pushed out of the transmission, and then the gear pair of another gear is put into the work. Before shifting gears, the clutch pedal must be stepped on, and the power transmission is interrupted, so that the meshing pair of the original gear can be disengaged, and the speed of the meshing part of the new gear meshing pair is gradually synchronized, so that the impact when entering the meshing can be greatly reduced, so as to achieve smooth gear shifting.

3. Prevent overload of the drive train.

When the car is braking urgently, if there is no clutch, the engine will be rigidly connected with the drive train and reduce the speed sharply, so all the moving parts will produce a large moment of inertia (its value may greatly exceed the maximum torque emitted by the engine when it is working normally), causing a load that exceeds its bearing capacity to the drive train, and causing damage to the parts. With a clutch, this danger can be eliminated by relying on the relative movement that may occur between the active and driven parts of the clutch. Therefore, we need a clutch to limit the maximum torque that the drivetrain can experience in order to be safe.

The clutch, as the name suggests, plays the role of separation and closing, that is, the separation of the engine and the wheel transmission.

That is to say, when you press the clutch, then the transmission of the engine is disconnected from the wheels, and the power of the engine is not transmitted to the wheels to drive the car.

The role of the clutch on the car:

1. It is conducive to the start of the car.

The car is stationary before starting, because the engine and the gearbox are rigidly connected, once the gear is hooked, the car will suddenly rush forward due to the sudden connection of power, which will not only cause damage to the parts, but also the driving force is not enough to overcome the huge inertia force generated by the car forward, so that the engine speed drops sharply and stalls.

If the clutch is used to temporarily separate the engine and the gearbox at the start, and then the clutch is gradually engaged, because there is a slip grinding phenomenon between the active part of the clutch and the driven part, the torque transmitted by the clutch can gradually increase from zero, and the driving force of the car also gradually increases, so that the car starts smoothly.

2. It is convenient for the car to shift gears.

In the process of driving the car, it often involves shifting gears to adapt to the needs of different driving environments, and when changing gears, the clutch will be used. The clutch can temporarily separate the engine from the gearbox, and the engine and the gearbox are temporarily separated by using the clutch to shift gears, then the original meshing of a pair of gears is removed due to the load, and the pressure between the meshing surfaces is greatly reduced, and it is easy to separate, if there is no clutch, the pressure between the meshing tooth surfaces is very large and difficult to separate, and it is easy to damage the parts.

3. Prevent damage caused by excessive pressure of the transmission system.

When the car brakes urgently, the wheels suddenly and sharply reduce speed, and the drive train connected to the engine still maintains the original speed due to the inertia of rotation, which often produces a moment of inertia in the transmission system that is much greater than the engine torque, making the parts of the drive train easy to damage.

4. Reduce torsional vibration impact.

The output torque of the automobile engine is usually unstable, the engine is running in the stroke, and the inertia of the rotation system of the engine itself can reduce the torsional vibration, but the remaining impact force still has an adverse effect on the subsequent gearbox and transmission shaft, and the damping spring in the clutch can significantly reduce the torsional vibration impact brought by the engine and prolong the life of the transmission gear.

The effect of the clutch is as follows: 1. Ensure that the car starts smoothly, the car is in a stationary state before starting, if the engine and the gearbox are rigidly connected, once the gear is hung, the car will suddenly rush forward due to the sudden connection of the power, which will not only cause damage to the parts, but also the driving force is not enough to overcome the huge inertia generated by the car forward rush, so that the engine speed drops sharply and stalls; 2. It is easy to shift gears, and during the driving of the car, different gearbox gears are often changed to adapt to changing driving conditions. If there is no clutch to temporarily separate the engine from the gearbox, the meshing force transmission gears in the gearbox will be difficult to separate because the load is not removed, and the pressure between the meshing tooth surfaces is very large; 3. To prevent the transmission system from being overloaded, when the car is braking urgently, the wheels suddenly and sharply reduce the speed, and the drive train connected to the engine still maintains the original speed due to the inertia of rotation, which often produces a moment of inertia far greater than the engine torque in the transmission system, so that the parts of the drive train are easily damaged.

Because the clutch relies on friction to transmit torque, when the load in the drive train exceeds the torque that can be transmitted by friction, the main and driven parts of the clutch will automatically slip, thus preventing the drive train from overloading; 4. To reduce the impact of torsional vibration, the working principle of the automobile engine determines the unstable output torque. In the power stroke, the combustion chamber gas** produces a great impact torque, while in other strokes, it is the inertial back-dragging engine.

The function of the clutch is to transmit and cut off the power transmission of the engine through the linkage mechanism according to the driver's wishes, and cooperate with the clutch plate to make the vehicle start smoothly, shift smoothly and prevent the engine from overloading.

The clutch is a component directly connected with the engine in the transmission system of the car, which is responsible for the cutting and combining of the power and transmission system, so it can ensure the smooth start of the car when it starts, and also ensure the smoothness of the gear shift, and also prevent the transmission system from overloading.

Clutch function and classification:

1. Function: The clutch is the same as the coupling, and the main thing is that it is used for the connection between the shaft and the shaft, so that they rotate together and transmit the torque.

2. Difference: It can be engaged or separated at any time during the operation or parking of the machine, and it is fast and reliable to achieve the intermittent control of the transmission system, so as to change speed and reversing; The clutch can also be used for overload protection, etc. The coupling must be disassembled after the machine stops running before the two shafts of the connection can be separated.

3. Application: start, stop, reversing and variable speed of mechanical transmission system.

4. Features: reliable work, rapid and stable combination and separation, accurate action, convenient adjustment and maintenance, convenient operation and labor-saving, simple structure, etc.

How to use the clutch correctly? The operation essentials of the clutch at the start are one fast, two slow, and three linkages, that is, when the pedal is lifted at the beginning; When the clutch is semi-linked, the pedal lifts slightly slower; While the clutch pedal is raised, gradually press the accelerator pedal according to the amount of engine resistance and start smoothly.

When shifting gears, the clutch pedal should be quickly pressed and lifted, and the phenomenon of semi-linkage should not occur, otherwise the wear of the clutch will be accelerated, and attention should be paid to the cooperation with the throttle during operation. In order to make the shift smoothly and reduce the wear and tear of the transmission shift mechanism and clutch, the two-foot clutch shift method is advocated, which is a good way to save money while driving.

The control method when braking is to press the brake pedal first, and then press the clutch pedal, so that the car can smoothly slow down and stop.

Do not step on the clutch when you have nothing to do, because the clutch on the car is in a tight engagement state when driving normally, and the clutch should not slip around.

Photo by Pacific Automobile Network Q&A).

The clutch is a transmission mechanism, it has an active part and a driven part, the two parts can be temporarily separated or slowly combined, and there may be relative rotation in the transmission process, so the clutch will rely on contact friction between the driving parts and the driven parts to transmit torque.

The clutch is located between the engine and the transmission, which is a component directly connected with the engine in the transmission system of the car, and can also be said to be the "switch" of the power transmission between the engine and the transmission, which is a transmission mechanism that can not only transmit power, but also cut off the power. The main function of the clutch is to ensure that the car can start smoothly, reduce the shock load of the transmission gear and prevent the drive train from overloading when changing gears.

The so-called clutch, as the name suggests, is to use "off" and "close" to transmit the right amount of power. The engine is always spinning, while the wheels are not. For a vehicle to stop without damaging the engine, the wheels need to be disconnected from the engine in some way.

The clutch controls the slip between the engine and the transmission, allowing us to easily connect a rotating engine to a transmission that is not spinning.

Clutch components

1) Active part: flywheel, pressure plate, clutch cover, etc.;

2) driven part: driven disc, driven shaft (i.e., the first shaft of the transmission);

3) Compression part: compression spring;

4) Control mechanism: release lever, release lever support column, swing pin, release sleeve, release bearing, clutch pedal, etc.

Clutch working state

The clutch is divided into three working states, namely full linkage without stepping on the clutch, semi-linkage when the clutch is partially pressed, and non-linkage when the clutch is pressed. When vehicle is in normal driving, pressure plate is tightly squeezed on the friction plate of flywheel, the friction force between pressure plate and friction plate is the greatest at this moment, and relative static friction is maintained between input shaft and output shaft, and both speed is the same. When the vehicle starts, the driver steps on the clutch, and the movement of the clutch pedal pulls the pressure plate to lean back, that is, the pressure plate is separated from the friction plate, and the pressure plate and the flywheel are not in contact at all at this time, and there is no relative friction.

The last one, which is the semi-linked state of the clutch. In this case, the friction between the pressure plate and the friction plate is less than that in the fully linked state. There is a sliding friction between the clutch pressure plate and the friction plate on the flywheel.

The speed of the flywheel is greater than the speed of the output shaft, and the part of the power transmitted from the flywheel is transmitted to the gearbox. At this point, the engine and the drive wheels are in a state of soft connection.

The most frequently asked questions about clutches

The friction material on the clutch disc is very similar to the friction material on disc brake pads or drum brake shoes and will wear out after a while. After the thinning, the clutch will start to slip and eventually it will not be able to transfer any power from the engine to the wheels.

Clutches wear out only when the clutch disc and flywheel rotate at different speeds. When they lock together, the friction material holds tightly against the flywheel and rotates in sync. Wear only occurs when the clutch disc slips against the flywheel.