mechanical braking system
DESCRIPTION
MECHANICAL BRAKING SYSTEM.pptTRANSCRIPT
MECHANICAL BRAKING SYSTEM
Submitted by Regikumar.K
3rd year mechanical
Mechanical brakes are assemblies consisting of mechanical elements for the slowing or stopping of shafts in equipment drives.They use levers or linkages to transmit force from one point to another. Braking slows or stops the movement of the coupled shafts.
INTRODUCTION
Brake System Principles
Kinetic Energy Mass Weight Speed Inertia and
Momentum
Band brakesDrum brakesDisc breaks . Cone brakes
TYPES OF MECHANICAL BRAKE
Band brakes, the simplest brake configuration, have a metal band lined with heat and wear resistant friction material
Drum brakes, which are commonly used on automobile rear wheels, work when shoes press against a spinning surface called a drum
Disc brakes are constructed of brake pads, a caliper, and a rotor. During operation, the brake pads are squeezed against the rotor
Cone brakes are made with a cup and a cone, which is lined with heat and wear resistant material. During actuation,the cone is pressed against the mating cup surface.
MECHANICAL BRAKES
TYPICAL SYSTEM
Disk Brake It Consists of two Brake
pads
Works similar to Bicycle Brake where two rubber pads rub against the wheel rim.
Disc Brake Parts
Calipers (4) Brake Pads Rotors (3)
Disc Brake Operation A piston inside the caliper
pushes the brake pads toward each other
The rotor is located between the pads
The squeezing effect causes friction which slows the car
Rotor warp from over tightened wheels which causes pedal vibration
Calipers can stick causing the brake pads to drag
Rear wheel disc brake parking brake mechanism can become stuck
Disc Brake Problems
HYDRAULIC DISC BRAKES
Disc mech bike
Loosen the caps on the mater cylinder Use a large screwdriver or pry bar to force
the piston back into the caliper Remove the bolts or clips that hold the
caliper to the mounting Remove the caliper and remove the pads Check the condition of the rotor, a worn or
grooved rotor will need machining
Servicing Disc Brakes
Put anti-squeal compound on the back of the pads Put new pads into the caliper Install the caliper into the mounting bracket Install the clips or bolts Press on the brake pedal several times until it is
firm Check the master cylinder fluid level and tighten
caps
Installing New Disc Brakes
Disc Brake Caliper Assembly
There are 2 types of CalipersFixed
Calipers are disc brakes that use a caliper that is FIXED in position and does not slide. They have pistons on both sides of the disc. There may be 2 or 4 pistons per caliper
Floating Much more commonSingle PistonEasier to work withOn “inboard” side of caliper
Caliper Types
Fixed Caliper
Applies two pistons to opposite sides of rotor
Caliper stays stationary
Disc Brakes require higher hydraulic pressure
Sliding Caliper
Applies pressure to two pads on opposite sides of rotor
CaliperSliding Fixed
Friction Material exposed to air
Drum BrakesExpanding shoes
create force on the inner surface of the drum
Used on the rear of some trucks and SUV’s
Self-energizing design requires less activation force
Require periodic adjustment
Drum Brake System
Drum Brake Parts Brake Shoes (5, 12) Backing Plate (14) Return Springs (3,
13) Hold Down Springs
(11) Self Adjusting Parts
(4, 7, 8, 10) Wheel Cylinder Parking Brake (6, 9) Drums
The wheel cylinder forces the brake shoes apart
The shoes are forced against a drum The friction changes rotary energy into heat
energy which slows the car The harder the shoes are forced apart, the
faster the car stops
Drum Brake Operation
Overheating the drums can cause them to warp or over expand (brake fade)
Springs can stretch over time causing the brakes to drag
Wheel cylinders can leak ruining the shoes
Parking brake cables can seize
Drum Brake Problems
Using a brake tool, remove the return springs
Remove the hold down springs Remove the self adjuster rod Note where the longer brake shoe is
located Remove the parking brake cable Remove the brake shoes together
Servicing Drum Brakes
Transfer all the self adjusting parts to the new shoes
Install on the backing plate Install the parking brake cable and self
adjuster rod Install the hold down and return springs Install the drum and adjust till the
shoes just hit the drum
Reinstalling Drum Brakes