forging new generations of engineers. brakes friction & braking friction: a force that opposes...
TRANSCRIPT
Forging new generations of engineers
Brakes
Friction & Braking
• Friction: A force that opposes motion, it prevents the sliding between two surfaces that are in contact.
• Amount of friction depends upon:– surface material– surface finish– force, acting upon the surfaces
• By using friction, brakes slow down or stop a rotating object.
Braking Action
• Brakes slow down a moving object by converting the kinetic energy of motion into another form.
• Most braking systems convert this kinetic energy into heat.
• The brake is cooled by moving air.
• If a brake becomes too hot, it will begin to lose its efficiency. This is called fade.
• Good brake design includes methods for adequate cooling of the brakes.
Brakes
• There are many different types of braking systems. Some of the more common types are:– Disc– Mechanical– Hydraulic– Pneumatic
Disc Brakes
• A friction pads is pressed against both sides of a rotating disc.
• This type of brake is commonly found on the front wheels of cars.
• They have good air flow around the brake which quickly dissipates heat.
Disc Brake
Mechanical Brakes
• Braking action is applied by physical force without the aid of hydraulics or pneumatics.
Hydraulics & Pneumatics
• Hydraulic and Pneumatic systems are closely related. Both use cylinders to produce a linear motion at varying speeds and forces.
• Hydraulics uses a fluid, hydraulic oil.• Pneumatics uses air.• Advantage of hydraulics is that oil can’t be
compressed.
Hydraulic - Pneumatic System
Hydraulic Brake