mechanical braking system

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