Introduction of Clutches and Brakes

Function of a clutch is to engage or disengage a machine (or machine component) without starting or stopping the driver. Different type of clutch serves different purposes. Such as;

• Slower, smoother engagement or disengagement under full speed.
• Quick engagement and disengagement.
• Overload protection by limiting the maximum torque loads.
• Prevent accidental machine reversal.

The sub assemblies of a clutch are pressure plate, friction disc and release bearing.

Brakes connects the driver to the wheel through the linkage and hydraulic circuits. The brake system on a vehicle is hydraulically activated by a mechanical linkage in the passenger compartment. The applied force is transmitted via hydraulics to the brakes at the front and rear axles. Mechanical devices apply the force to the braking components at the wheels.

Braking

As the driver presses downward on the brake pedal, the movement of the pedal is transmitted to the piston in the master cylinder. The piston pressurize the brake fluid and attempt to push it at the brakes line. Since this is a sealed system the pressurized fluid transmit the applied driver's force to the output piston at the wheels. The piston may be in a wheel cylinder or disc caliper. The pistons act against the drum brake shoes or disc brake pads respectively.

Releasing

When the brake pedal is released, return springs at the pedal, inside the master cylinder, and the drum brake shoes retract each of the brake components to the rest position.

Brake Fluids.

Brake fluid act as the transfer agent to transmit the driver's braking input to the mechanical force at the wheels' braking component. The different classification of brake fluids are generally based on the fluids boiling point.

Boiling fluid should have a minimum boiling point of 204°C. If the brake fluid were allowed to boil, then gases would form within the brake lines and hoses, reducing the braking effect at the wheels.

A second requirement of brake fluid is that it should be non corrosive or least corrosive-resistant.

Even the best brake fluids will deteriorate over a period of time or usage and this will affect the sealants and metal components of the brake system.