Disc Brakes

 This is part of my Brief Guide To Brakes series – a result of my research for Edinsolar, the University of Edinburgh’s solar vehicle team.

LabelledDiscBrakeMechanism

HOW IT WORKS

• Hydraulic piston pushes calipers together
• The calipers press the brake pads against the disc
• Friction from the pads slows the disc
• The wheel slows down

DiscBrakeMechanismStages

The piston has a seal called the square-cut seal that becomes twisted when dragging and stretching along while the piston moves in and out but returns to its original shape when the brakes are released.

VARIATIONS

The calipers can be forced together mechanically, hydraulically, pneumatically or electromagnetically.

The discs can be:
vented
– hollowed with fins and vanes to cool
cross-drilled
– holes drilled in the sides of the discs to cool and remove water
– can be the source of stress cracks under severe conditions
slotted
– shallow channels are machined into the disc to help remove gas, dust and water
– wears down the brake pads – removing material keeps them soft and prevents vitrification or glazing of the brake pads, especially in a racing environment

Often the discs are made from cast iron, particularly a type called Grey Iron, but in racing most cars use reinforced carbon and in some very niche vehicles, ceramic composites.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s