21-10-2016, 12:02 PM
1460347455-PneumaticbrakingsysytemR.doc (Size: 1.18 MB / Downloads: 5)
INTRODUCTION
Ever since the invention of the wheel, it there has been “go” there has been a need for “whoa”. As the level of technology of human transportation has increased, the mechanical devices used to slow down and stop vehicles has also become more complex. In this report I will discuss the history of vehicular braking technology and possible future developments. Before there was a “horse-less carriage,” wagons, and other animal drawn vehicles relied on the animal’s power to bath accelerate and decelerate the vehicle. Eventually there was the development of supplemental braking system consisting of a hand level to push a wooden friction and pad directly against the metal tread of the wheels. In wet conditions these crude brakes would lose any effectiveness.
In this era is the first record of the disk brake. Dr. F.W. Lanchester patented a design for a disk brake in 1902 in England. It was incorporated into the Lanchester car produced between 1906 through 1914. These early disk brakes were not as effective at stopping as the contemporary drum brakes of that time and were soon forgotten. Another important development occurred in the 1920’s when drum brakes were used at all four wheels instead of a single brake to halt only the back axle and wheels such as on the ford model. The disk brake was again utilized during World War II in the landing gear of aircraft. The aircraft disk brake system was adapted for use in automotive applications, first in racing in 1952, then in production automobiles in 1956. United States auto manufactures did not start to incorate disk brakes in lower priced non-high-performance vehicles until the late 1960’s.
Nowadays, brake system is probably the most important system for vehicle. Most vehicles have disc brakes on the rear wheels, and some have disc brakes on all wheels. This is the part of the brake system that does the actual work of stopping the vehicle. The main thing in the braking system is caliper, master cylinder, disc brake or rotor and the hose or piping. Research and comparison are done to make sure the flow of the project run smoothly. To design the suitable breaking system for any disk brake of vehicles must depend on the speed the vehicle, maximum weight of baggage and weight driver and body. From the research that we get from the design before, for suitable these disk breaking system to use is motorcycle etc. There are designed a pneumatic based disk braking system.
AIM OF THE PROJECT
The Aim of this project is to design a pneumatic disk braking system by using air compressor and valve. If we don’t have diesel, petrol, etc. then we can design braking system through this project technology in our future.
Hardware requirements:
1) Pneumatic Cylinder
2) Air compressor
3) Pneumatic valve
4) Relay
5) Disk
6) Battery
7) Motor
8) Switch
WORKING OF THE PROJECT
Firstly we connect the supply from compressor and relay. When the air from compressor, this air goes to pneumatic valve and it will be taking a decision to move the brake through pneumatic cylinder. When we press the switch continuously then pneumatic cylinder applies the brake on disk and disk rotation will be stopped. If we don’t press the switch then pneumatic cylinder release the brake and disk rotation will be started again continuously.
AIR COMPRESSOR:
An air compressor is a device that converts power (using an electric motor, diesel or gasoline engine, etc.) into potential energy stored in pressurized air (i.e., compressed air). By one of several methods, an air compressor forces more and more air into a storage tank, increasing the pressure. When tank pressure reaches its upper limit the air compressor shuts off. The compressed air, then, is held in the tank until called into use. The energy contained in the compressed air can be used for a variety of applications, utilizing the kinetic energy of the air as it is released and the tank depressurizes. When tank pressure reaches its lower limit, the air compressor turns on again and re-pressurizes the tank.
Pneumatic cylinder
Pneumatic cylinder(s) (sometimes known as air cylinders) are mechanical devices which use the power of compressed gas to produce a force in a reciprocating linear motion.
Like hydraulic cylinders, something forces a piston to move in the desired direction. The piston is a disc or cylinder, and the piston rod transfers the force it develops to the object to be moved. Engineers sometimes prefer to use pneumatics because they are quieter, cleaner, and do not require large amounts of space for fluid storage.
General
Once actuated, compressed air enters into the tube at one end of the piston and, hence, imparts force on the piston. Consequently, the piston becomes displaced.
COMMON TYPE OF CYLINDER:
There are many different cylinder types. The most common are listed below: Single acting cylinder - a cylinder in which air pressure is applied to the movable element (piston) in only one direction.
Spring return cylinder - a cylinder in which a spring returns the piston assembly.
Ram cylinder - a cylinder in which the movable element is the piston rod.
Double acting cylinder - a cylinder in which air pressure may be alternately applied to the piston to drive it in either direction.
Double acting – double rod cylinder - Double acting cylinder with a piston rod extending form each end. The piston rods are connected to the same piston. Double rod cylinders provide equal force and speed in both directions.
Cylinder size:
To determine the size cylinder that is needed for a particular system, certain parameters must be known. First of all, a total evaluation of the load must be made. This total load is not only the basic load that must be moved, but also includes any friction and the force needed to accelerate the load. Also included must be the force needed to exhaust the air from the other end of the cylinder through the attached lines, control valves, etc. Any other force that must be overcome must also be considered as part of the total load. Once the load and required force characteristics are determined, a working pressure should be assumed. This working pressure that is selected MUST be the pressure seen at the cylinder's piston when motion is taking place. It is obvious that cylinder's working pressure is less than the actual system pressure due to the flow losses in lines and valves. With the total load (including friction) and working pressure determined, the cylinder size may be calculated using Pascal's Law. Force is equal to pressure being applied to a particular area. The formula describing this action is:
Force = Pressure * Area
Force is proportional to pressure and area. When a cylinder is used to clamp or press, its output force can be computed as follows:
F = P * A
P = pressure (PSI (Bar) (Pascal's))
F = force (pounds (Newtons))
A = area (square inches (square meters))
These pressure, force and area relationships are sometimes illustrated as shown below to aid in remembering the equations.
F = P * A
P =F/A
A =F/ P
PNEUMATIC VALVES:
Control valves are fundamental components of any pneumatic system. Selecting the right air valves to control system and pressure, direction of flow and rate of flow is crucial when designing fluid power circuitry. If the pneumatic valve is too big for your application, you will be wasting air and money. If its too small, the actuator will not function properly.
The Pneumatic Advantage:
• Variety of porting options for plumbing convenience.
• Numerous configurations for added versatility.
• Flow rate range from 2.90 to 57 scfm at 125 psi.
• Proppet or spool designs.
• Operating pressures from 26” Hg to 150 psi.
• Miniature size is ideal for limited space applications.
• Long product life.