Vibration problems associated with clutch drums and solutions

In the process of driving a car, we may encounter a vibration problem related to the clutch, which is called "Crowd". This kind of vibration generally occurs when the accelerator pedal is depressed. If it occurs at low speed, it is called "Lugging". In the high gear of 30~40 km/h, Crowd jitter is the most serious.

So, how to solve this vibration problem? Mainly from the following two aspects.

First, the cycling torque of the engine is an important factor in the severity of Crowd jitter. Generally speaking, the more cylinders the engine has, the less disturbance it will cause to the transmission system and the body. For example, for a 4-cylinder engine, the severity of Crowd jitter has a lot to do with the engine output torque. Therefore, Crowd jitter can be effectively controlled by improving engine design to reduce internal imbalance forces and pulses generated by combustion.

Secondly, the natural frequency of the transmission system is also one of the factors that affect Crowd jitter. According to NVH experience, Crowd jitter usually occurs in the range of 900-1200rpm, corresponding to the transmission system frequency between 30 and 40Hz. If the torsional resonance response of the transmission system can be reduced below the engine excitation frequency, the severity of the Crowd will be greatly reduced. In order to achieve this goal, it can be achieved by adjusting the spring coefficient in the clutch, the torque damper and increasing the inertia of the flywheel. By reducing the spring coefficient and improving the timeliness of gear shifting, the Crowd jitter of 3 gears at 900rpm can be reduced.