The clutch disc, also known as the driven disc, is a core component in a vehicle's clutch system. Its function is to transmit and disconnect engine power through its interaction with the pressure plate and flywheel. Here's a detailed explanation:

I. Structural Components
A clutch disc typically consists of the following components:

Driven disc body: A splined hub is located in the center of the driven disc, connecting to the splines of the transmission input shaft (driven shaft) to ensure synchronized power transmission.

Friction plate: Double-sidedly coated with a high-friction material (such as asbestos or silicon carbide), it contacts the flywheel and pressure plate, transmitting torque through friction.

Torsional vibration damper: Built-in damping springs and damping elements absorb engine speed fluctuations and reduce transmission vibration and noise.

Steel disc and driven disc hub: The steel disc is connected to the driven disc hub via rivets. Radial grooves prevent thermal deformation and ensure structural stability.

II. Working Principle
A clutch disc operates in three stages:

Engaged:
When the clutch pedal is not depressed, the pressure plate, acting as a spring, presses the clutch disc firmly against the flywheel. Engine power is transmitted through the flywheel, pressure plate, clutch plate, and transmission input shaft, allowing the vehicle to travel normally.

Disengaged State:
When the clutch pedal is depressed, the pressure plate moves backward, separating the clutch plate from the flywheel and interrupting power transmission.

Gear shifting can now be performed, preventing gear shock.

Partially Engaged State:
When the pedal is slowly released, the pressure plate and clutch plate partially contact, generating sliding friction.

This is used for starting the vehicle or slow-speed creeping to prevent engine stalling or vehicle jerking.

III. Core Functions

Power Transmission:
Transmits the rotational power of the engine crankshaft to the transmission through friction, driving the vehicle forward.

Shift Assist:
During disengagement, power is cut off, allowing the gears to engage under no-load conditions, reducing wear and shock.

Vibration Cushioning:
The torsional vibration damper absorbs engine torque fluctuations, protecting transmission components.

Overload Protection:
During sudden braking, the clutch plate slips to prevent overload damage to the transmission. IV. Types and Classifications
Based on structural differences, clutch plates can be divided into the following categories:

Single-plate clutch plates:
For ordinary passenger cars, they transmit power through a single friction surface and have a simple structure.

Dual-plate clutch plates:
An additional friction surface doubles torque transmission capacity and are primarily used in heavy-duty vehicles.

Diaphragm spring clutch plates:
Use a diaphragm spring instead of a traditional coil spring, combining both clamping and release functions with a compact structure.

V. Maintenance and Failures
Common Failures:
Slipping: Friction plate wear or insufficient pressure on the pressure plate leads to power transmission failure.

Noise: Friction plate burnout or exposed rivets produce metallic grinding sounds.

Jitter: Clutch plate deformation or damping spring failure causes transmission system vibration.

Maintenance Recommendations:
Check friction plate thickness regularly and replace when wear reaches its limit.

Avoid prolonged operation in partial clutch mode to reduce the risk of friction plate overheating.

When replacing the plate, simultaneously check the pressure plate and flywheel to ensure smooth contact surfaces.