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There are several types of brakes, but our goal here is not to present their features. We will only take you through a slow, slow journey to the beginning of the braking systems. As for who came up with the idea of a braking system, no individual person can be credited for it. As the saying goes, what goes up must come down, or to paraphrase it, what goes fast, must stop. It was only obvious that whoever made a moving object, devised a stopping system as well. So it's rather a matter of who brought what to the idea, than who actually invented it.
Disk Brake
Introduction
The
meaning of a break means interrupt
(continuity, sequence, or course). In Automobile we use the term break as the interruption
of speed. In a little over a hundred years since the
automobile took hold of people's imagination, technologies designed to make
them accelerate faster and reach higher speeds have evolved with a fury the
likes of which we can only see in the aeronautics industry. Still, despite
chargers, turbochargers, twin turbochargers or NOX, there are limits which
cannot be surpassed by a land based vehicle in terms of speed, be it because of
technological limitations or the laws of physics.
Not the same can be said about the rather unseen part of the automotive evolution: brakes. The only limitations imposed to them are in connection with the human body's ability to withstand rapid decelerations. Otherwise, it would be a lot easier stopping a car than making it go insanely fast.
Whether they come in the form of drum brakes, as was the case in the dawn of the automobile, or as discs, the brakes have been the horsepower's companion throughout the decades, each pulling the evolution of the car in different directions.
Not the same can be said about the rather unseen part of the automotive evolution: brakes. The only limitations imposed to them are in connection with the human body's ability to withstand rapid decelerations. Otherwise, it would be a lot easier stopping a car than making it go insanely fast.
Whether they come in the form of drum brakes, as was the case in the dawn of the automobile, or as discs, the brakes have been the horsepower's companion throughout the decades, each pulling the evolution of the car in different directions.
Types of Brake
There are several types of brakes, but our goal here is not to present their features. We will only take you through a slow, slow journey to the beginning of the braking systems. As for who came up with the idea of a braking system, no individual person can be credited for it. As the saying goes, what goes up must come down, or to paraphrase it, what goes fast, must stop. It was only obvious that whoever made a moving object, devised a stopping system as well. So it's rather a matter of who brought what to the idea, than who actually invented it.
·
Wooden Block
The early braking systems to be used in
vehicles with steel rimmed wheels consisted of nothing more than a block of wood and a lever system. When he
wanted to stop, the driver had to pull the lever located next to him and make
the wooden block bear against the wheel.
The method proved effective in both horse drawn or steam powered vehicles. It started becoming obsolete towards the end of the 1890s, when the Michelin brothers began replacing steel rimmed wheels with the rubber tire. The wood block method, needless to say, was useless in conjunction with rubber.
The method proved effective in both horse drawn or steam powered vehicles. It started becoming obsolete towards the end of the 1890s, when the Michelin brothers began replacing steel rimmed wheels with the rubber tire. The wood block method, needless to say, was useless in conjunction with rubber.
·
Slowly Grinding to a Halt
The drum based
braking system can be considered the forefather of the modern day break. A
forefather who is still alive, as drum brakes are still in use today.
The man largely credited with the development of the modern day drum brake is French manufacturer Louis Renault, in 1902. Still, crude concepts of the drum existed before that. Wilhelm Maybach had used a similar, yet simpler design a year earlier. Even prior to that, in 1899, Gottlieb Daimler came up with the idea to wrap a cable around a drum and anchor it to the vehicles chassis. The forward motion of the car tightened the cable, making it easier for the driver to pull the lever and get the wood block to do its work. What Daimler came up with is called servo assistance and is still in use today, with the required enhancements, obviously.
These types of braking systems were all external, a feature which soon turned into a problem. Dust, heat and even water rendered them less effective. It was time for the internal expanding shoe brake. By placing the shoes inside the drum brake, dust and water were kept out, allowing the braking process to remain effective
The man largely credited with the development of the modern day drum brake is French manufacturer Louis Renault, in 1902. Still, crude concepts of the drum existed before that. Wilhelm Maybach had used a similar, yet simpler design a year earlier. Even prior to that, in 1899, Gottlieb Daimler came up with the idea to wrap a cable around a drum and anchor it to the vehicles chassis. The forward motion of the car tightened the cable, making it easier for the driver to pull the lever and get the wood block to do its work. What Daimler came up with is called servo assistance and is still in use today, with the required enhancements, obviously.
These types of braking systems were all external, a feature which soon turned into a problem. Dust, heat and even water rendered them less effective. It was time for the internal expanding shoe brake. By placing the shoes inside the drum brake, dust and water were kept out, allowing the braking process to remain effective
·
Hydraulic Power
The end of
the mechanically-activated brakes came in 1918, when Malcolm Loughead, one of
the founders of what later was to become Lockheed Aircraft Corporation, came up
with the idea. Loughead put together a four-wheel hydraulic-brake system for
cars. This system used fluids to transfer the force on the pressed pedal to the
pistons and then to the brake shoes.
The four-wheel hydraulic system was first used on the 1918 Duesenberg and quickly caught on, mostly thanks to the fact that it made braking much easier than in a mechanical system. By late 1920s, this system was fitted on most high-priced vehicles and soon after it expanded to most of the automotive world.
The four-wheel hydraulic system was first used on the 1918 Duesenberg and quickly caught on, mostly thanks to the fact that it made braking much easier than in a mechanical system. By late 1920s, this system was fitted on most high-priced vehicles and soon after it expanded to most of the automotive world.
·
The Disc
As the vehicles spilled out the assembly plants,
they started becoming both faster and heavier. Hydraulic drum based brakes were
effective, but they had a tendency to ineffectively distribute heat. This
feature made room for the creation of the disc braking
system.
Even if it came to be, basically, at around the
same time with the drum brake system, the disc had to go a long way before
getting a place in the spotlight. First patented in 1902 by William Lanchester,
the disc became popular in the 1950s.
Using the disc brake in conjunction with Loughead hydraulics, Chrysler became the first manufacturer to implement the system on its vehicles (Imperial). In Europe, the system was adopted by Jaguar (C-Type) and Citroen (DS).
Still, the system was dropped for a few years in the US, as it still required some significant effort from the driver to operate it. It was only in 1964 when it made its final comeback, featured on the Studebacker Avanti. This time it succeeded.
The difference was made by the development of the power braking system. By assisting the movement of the piston in the master cylinder, the driver no longer had to apply as much pressure to get the car to stop effectively.
Using the disc brake in conjunction with Loughead hydraulics, Chrysler became the first manufacturer to implement the system on its vehicles (Imperial). In Europe, the system was adopted by Jaguar (C-Type) and Citroen (DS).
Still, the system was dropped for a few years in the US, as it still required some significant effort from the driver to operate it. It was only in 1964 when it made its final comeback, featured on the Studebacker Avanti. This time it succeeded.
The difference was made by the development of the power braking system. By assisting the movement of the piston in the master cylinder, the driver no longer had to apply as much pressure to get the car to stop effectively.
·
ABS (Anti blockier system),
The evolution of the brakes themselves has since slowed down.
Additional systems though took off. ABS (Anti blockier system), electronic
brake-force distribution (EBD), brake assist and many other systems have come
to help braking become as effective and as safe as it can be. Still, the
foundations first set in the early 1900s remain the basis for modern day
brakes.
Disk Brake
A disc brake is a type of brake that uses calipers to squeeze pairs of pads against
a disc in order to create friction that retards the rotation of a shaft,
such as a vehicle axle, either to reduce its rotational
speed or to hold it stationary. The energy of motion is converted into waste heat which must be dispersed. Hydraulic disc brakes are the most commonly used
form of brake for motor vehicles but the principles of a disc brake are
applicable to almost any rotating shaft.
Compared
to drum brakes, disc brakes offer
better stopping performance because the disc is more readily cooled. As a
consequence discs are less prone to the brake
fade caused when brake components
overheat. Disc brakes also recover more quickly from immersion (wet brakes are
less effective than dry ones).
Most
drum brake designs have at least one leading shoe, which gives a servo-effect. By contrast, a disc
brake has no self-servo effect and its braking force is always proportional to
the pressure placed on the brake pad by the braking system via any brake servo,
braking pedal, or lever. This tends to give the driver better "feel"
and helps to avoid impending lockup. Drums are also prone to "bell
mouthing" and trap worn lining material within the assembly, both causes
of various braking problems.
The
brake disc (or rotor in American English) is usually made
of cast iron, but may in some
cases be made of composites such as reinforced
carbon–carbon or ceramic matrix composites. This is
connected to the wheel and/or the axle. To retard the wheel,
friction material in the form of brake
pads, mounted on the brake
caliper, is forced mechanically, hydraulically, pneumatically, or electromagnetically against both sides of the disc. Friction causes the disc and attached wheel to
slow or stop.
The development of disc-type brakes began
in England in the 1890s, but they were not practical or widely available for
another 60 years. Successful application required technological progress, which
began to arrive in the 1950s, leading to a critical demonstration of
superiority at the
Le Mans auto race in 1953. The Jaguar racing team won, using disc brake equipped cars, with
much of the credit being given to the brakes' superior performance over rivals
from firms like Ferrari, equipped with drum
brakes. Mass production quickly followed with the
1955 Citroën DS.
History
of Disk Brake
Development of disc brakes began in England in the 1890s. The
first caliper-type automobile disc brake was patented by Frederick William Lanchester in his Birmingham factory in 1902 and
used successfully on Lanchester
cars. However, the limited choice of metals in this period meant that he had to
use copper as the braking medium acting on the disc. The poor state of the
roads at this time, no more than dusty, rough tracks, meant the copper wore
quickly making the system impractical.
The
American Crosley Hot Shot is often given credit for the
first production disc brakes. For six months in 1950, Crosley built a car with
these brakes, and then returned to drum brakes. Lack of sufficient research
caused reliability problems, such as sticking and corrosion, especially in
regions using salt on winter roads. Drum
brake conversions for Hot Shots were quite popular. The Crosley disc was a Goodyear development, a caliper type with
ventilated disc, originally designed for aircraft applications.
Chrysler developed a unique braking system,
offered from 1949 to 1953. Instead of the disc with caliper squeezing on it,
this system used twin expanding discs that rubbed against the inner surface of
a cast-iron brake drum, which doubled as the brake housing. The discs spread
apart to create friction against the inner drum surface through the action of
standard wheel cylinders. Because
of the expense, the brakes were only standard on the Chrysler Crown and the Town and Country Newport in 1950. They were optional, however,
on other Chryslers, priced around $400, at a time when an entire Crosley Hot
Shot retailed for $935. This
four-wheel disc brake system was built by Auto Specialties Manufacturing
Company (Ausco) of St. Joseph,
Michigan, under patents of inventor H.L. Lambert, and was first tested on a
1939 Plymouth. Chrysler discs were "self-energizing,"
in that some of the braking energy itself contributed to the braking effort. This was accomplished by small balls
set into oval holes leading to the brake surface. When the disc made initial
contact with the friction surface, the balls would be forced up the holes
forcing the discs further apart and augmenting the braking energy. This made for lighter braking pressure
than with calipers, avoided brake fade, promoted cooler running, and provided
one-third more friction surface than standard Chrysler twelve-inch drums. Today's owners consider the
Ausco-Lambert very reliable and powerful, but admit its grubbiness and
sensitivity.
Types of Disk Brake
Instead of traditional expanding breaks that press outward
against a circular drum. Disk break utilize a cast iron rotor (disk) with brake
pads positioned on either side of it. Breaking effect is achieved in a manner
similar to the way squeeze a spinning disk between fingers.
There are three types of disk brakes:
·
A Fixed caliper
·
A Floating Caliper
·
A Sliding Caliper
A Fixed caliper
It is used one or two pistons mounted on each side of the
rotor (in each side of the caliper). The caliper mounted rigidly and does not
move. The following Image shows in detailed,
A Floating Caliper
Floating caliber use threaded guide pins and bushing, or a
sleeve to allow the caliper to side and apply the brake pads.
The working of disk Breaks
Let's take a
look at the basic disc brake system and how it works...
The
components:
- Master
Cylinder
- Steel
brake lines
- Proportioning
valve
- Brake
calipers
- Brake
rotors or discs
- Brake
pads, anti-rattle hardware, and siding mechanisms (IE: pins)
1. The master cylinder is mechanically connected to the brake
pedal through a system of steel rods called linkage. These rods operate at
different angles using bushings that are usually made of nylon, rubber, or
Teflon. When you step on the brake pedal, the linkage pushes on a steel rod
that pushes into the back of the master cylinder. The master cylinder is
nothing more than an elaborate pump that forces break fluid through the braking
system to energize the various components that stop your car.
2. The steel brake lines are the infrastructure that provides
a pathway for the brake fluid to travel through to do its job.
3. The Proportioning valve measures and adjusts the amount of
fluid that goes to the front Vs. back brakes, because each set of brakes
require different volumes and pressures to equally brake and stop the car.
4. The brake calipers are nothing more than powerful
"C" clamps that are actuated by hydraulic pressure which occurs when
the driver depresses the brake pedal, creating hydraulic pressure within the
system. The calipers have large pistons inside of them that, when brake fluid
pushes behind them, are forced outward ... creating a clamping action on the
pads, which are in contact with the rotors.
5. Brake rotors or discs are flat round steel discs that are
attached to the car's wheels. The calipers straddle over them and, when the
brake pedal is depressed, the calipers clamp down on them, causing the brake
pads to make contact with the rotors, creating friction and thus stopping the
car.
6. Attached to the calipers are brake pads. They are the
friction material that is needed to stop the forward motion of the wheels.
Specifically, these pads are made of steel backing with friction material
affixed to it, either by the use of industrial grade glue or steel rivets.
Anti-rattle hardware consists of spring-steel clips that are affixed to the
brake pads to keep them in place on the brake caliper. Without this hardware,
the pads would rattle, causing clicking and squealing noises when the wheels
are in motion. The sliding mechanisms are usually pins upon which the calipers
slide. They are attached to the steering knuckle in such a way as to position
the brake calipers so that they straddle the disc with the pads attached to
them. When the brake pedal is depressed, the hydraulic pressure generated
within the system forces the piston within the caliper outward; this causes the
brake pads to clamp onto the discs, creating the friction necessary to stop the
forward motion of the wheels. The sliding mechanisms must be clean, lubricated,
and moveable for the calipers to apply and release the brake pads on the discs.
References.
·
http://arrc.ebscohost.com/ebsco_static/repairips/8852.htm#8852CH26_Disc_Brakes.htm
·
https://en.wikipedia.org/wiki/Disc_brake#Early_experiments
