Cars and Tuning

The mission of the braking system is to create a force regulated to reduce speed or to stop a moving vehicle, and to have it parked…

This action braking is achieved through a friction that is, through the resistance to relative motion of two surfaces in contact, causing one of them, stationary, contact with another mobile, which will involve the reduction of speed of the latter, the system used to achieve the braking cars. The braking action is, therefore, absorb heat energy, when you flick a moving part solidarity to the wheels, (drums and discs) against a fixed part on the vehicle (shoes and pads). The thermal energy generated in the elements frenantes is transmitted to the atmosphere.
The engine brake is used to reduce speed, first, to take our foot off the accelerator, the engine being dragged by the rotation of the wheels and serves a little help to brake normally.
The brake system consists of:
System command.
Frenante or element.
Element frenante
We employ two braking systems as elements employees and how to operate the moving part:
System or drum brakes.
System or disc brakes.
• System drum brakes
Overview
In Figure 1 represents the components of a system of brake drum. These are:
– Bombín.
– Spring lower union shoes.
F – Retention jagged.
H – frenante Garrison.
J – Plato portazapatas.
L – Pier higher zapa-tion.
N – Traverse command shoes.
T – drum.
Z – Zapata.

Drum Brake
The brake drums are manufactured in cast iron perlítica centrifuged.
To achieve resistance, while power dissipation convenient, nerves are often added to the outside of the drums.
The friction surface of the drums must be fully mechanized, to get a precise finish, as well as a rigorous and focused a uniform surface.
Plato portazapatas
It is a dish or disk that supports the pads and the mechanisms of mechanical or hydraulic drive.
Shoes
The shoes are built forged or stamped steel or aluminium smelter, most used the steel stamping, since they can occur in large numbers and reduced prices.
To establish contact with the inner surface of the drum, the pads are coated with a lining riveted or glued.
The shoes must have the following characteristics:
O A hardness below the inner surface of the drum, to increase its duration.
Resistance or mechanical abrasion, high temperatures and undeformable.
O A high coefficient of friction.
For this purpose materials that meet these properties, such as synthetic resins and compounds minerals (based on carbon, sulfur, barium, magnesium and manganese).
The actuation of the brake drum can be by mechanical means, hydraulic or pneumatic.
Functioning

The drum is slowed down by the action of two pads, but for more clarity in the explanation has been drawn in only one.
The shoes presented in both hands in a hole which is inserted a pin on that tour, and the other end is supported by a cam (motorized drive) or pistons (hydraulic) bombín.
When activated brake pedal or the cam turns or moves the pistons of bombín, thus opening the pads, turning on pivots. This makes linings of the pads in contact with the brake drum, reducing the rotational speed of the same and thus the wheel.
When not activated brake pedal, the docks (L and C) joining the pads, make them return to their original position.
Bombín the wheel

The cylinders or bombines of the wheels are, in general, set on the decks portazapatas.
The fluid pressure enters the cylinder with a hole.
Each cylinder consists mainly of:
Two or opposing pistons.
Two or copelas sealing rubber.
A pier or intermediary that maintains the copelas applied on the face of the piston.
Pistons acting directly or through the intermediary of buttons on the pads.
Each cylinder end is protected by a rubber overall. At the bottom of each bombín will put a screw purge.
At the curb, the pressure acting on the two pistons, which in turn applied the brake pads against the drums. After braking, the brake pads recover their initial position by the action this spring and under the pistons back to their original position, expelling the liquid.

• System disc brakes
The current trend is to put on vehicles drum brakes at the rear and disk at the front, although there are vehicles that are equipped with disc brakes on all four wheels,
The advantages over drum brakes are as follows:
Best or cooling of the whole.
Or less slack in the pedal brake pads for being very close to the disk.
Greater efficiency or braking.
System maintenance easier.
Increased difficulty or to display the fading as it is more chilled.
Overview

The stirrup, or clamp jaws, consists of:
A fixed or fork to portamangueta.
O Two cylinders containing the pistons.
The Pistons will or the brake disc which joins the wheel through the disc clamping, all mounted on semieje or mangueta.
O The brake pads were interspersed between the pistons and brake disc.
The tightness of the piston is made by a board of rectangular section, which also ensures the recoil of the piston.
An overall subject with a ring prevents oxidation of the piston.
Functioning
Under the action of the pressure in the cylinder pistons applied against disc pads on both sides deteniéndolo.
By eliminating pressure in the cylinder is released on disc.
There are no springs or separation recovery piston.
O The disc is made of cast iron perlítica.
The jaws or with the pads reach approximately 1 / 5 of the disk surface.
Types of disc brake
The types of disc brakes is determined by the number of pistons and the system of holding the jaws.
Depending on the number of pistons
According to the system of holding the jaws

– Two pistons.
– Four Pistons.
– Mordaza fixed.
– Mordaza mobile or floating.
Depending on the number of pistons
Two or Pistons
In this brake, the most widely used, the jaw contains two pistons.
Four or Pistons
Employed in high-performance vehicles. Used four piston, which increases the capacity and effectiveness of the braking.
According to the system of holding the jaws
If the jaws are fixed, each pill is driven by a piston (9). If the jaws are mobile or floating, generally only takes a plunger to push on the one hand to the pad and on the other will be the jaws that clamp or pull, the pill also pushing against hard and getting the same action braking.

Brake control system
The brake control system is the set of elements used to create the force that will give you motion cam, pistons or to the membrane, according to the brake system used. Both disc brakes as the drum use the same command systems.
We distinguish the following types:

• System mechanic.
• Hydraulic system.
• System tire.
• System hidroneumático.

A. Command brake pedal.
B. Bombra command hidáulico circuit.
C. Steel cables.
D. Deposit expansion liquid filling circuit.
F. Correcting braking.
G. Pipe command rear brakes.
I. Switch command brake lights.
K. Zapata brake later.
L. Bar command.
N. Command piston rear brakes.
Q. Lever.
R. Device Regulatory parking brake control cable.
S. Servo command frenos.T drum brake.
U. Disc brake.
X. Zapata brake later.
Y. Racor three tracks.

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• System mechanic (parking brake)
Overview

It consists of a mechanical brake mechanism, called hand or parking brake, operated from inside the vehicle through the lever so that, once the command set, the wheels are blocked to prevent the movement of the vehicle. This mechanism applies generally to the rear wheels and when the vehicle is immobilised.
The lever activates the flexible steel cables.
Operation System brake drum
The displacement of the pads is obtained by means of a lever mechanism and a rod empujadora (fig.12).
The command is carried by cable and is usually performed in the following manner:
At the operating lever on the cable, it serves pushing left empujadora rod, which approximates the caliper to the drum.
The lever on his top approaching the caliper to the drum. Once approximate two shoes, as the action of the cable continues, the pressures of the pads on the brake drum makes it immobilize.

If the system is disk, the hand brake or parking drives as follows:
Lever turns in the direction of the arrow moving the cam, which drives the pusher, using the pad against the disc. The pill acts by the reaction being put on the jaws.
• Hydraulic system
The operation of the hydraulic systems are based on two principles:
Or liquids are almost incompressible. The same pressure that runs on the pump reaches full brakes to bombines.
When a liquid, totally enclosed in a container, it applies pressure on one point, that pressure is communicated throughout the mass of liquid with the same intensity.
The strength gained in each cylinder is proportional to the surface area of each piston being higher, therefore, pistons, which have more diameter.
The braking system with hydraulic control must therefore allow to spread the braking effort on 4 wheels. It is necessary to provide elements 4 receptors (bombines).
The system consists essentially of:

A tank or brake fluid.
A bomb or principal.
O A command or brake pedal.
Or cylinders receptors (bombines).
Or pipes linking the different elements.
Main Pump

It consists of a casting where inside a cylinder by a piston that moves.
The axis of the piston rod is placed solidarity at its other end, to pedal.
On the opposite side of the piston connecting with a hole in the pipe is closed by a valve double effect, held on to his seat by a rubber spring.
The other end of the piston (hand pedal) is a roadblock manned by rubber, ensuring tightness.
The top of the cylinder is linked to the depot for a liquid diet and a hole hole expansion, much smaller than the first.
Operation of the pump or to actuate the pedal
By operating the pedal, the tip of the push rod is going to build against the piston after having travelled a short trip (about 1mm.), Which provides free travel of the pedal.
By continuing treading, the piston moves slightly in the cylinder and closes the hole dilation isolate the camera tank feeding.
The dilation hole is closed, the progress of the piston increases the pressure when the pressure exceeds the action of the small valve spring, it will open and the liquid will be sent by pipeline to the wheel cylinders (bombines).
Pistons bombines of pressure against the pads drums.
Or Operation of the pump to release the pedal
When the pedal is released:
By the action of its spring shoes recover their rest position by dragging them to the pistons of bombines of the wheels, the liquid returns to the main pipe to the pump.
The piston pump for a spring primary recovers his starting position, creating a pressure drop in the circuit, which makes the liquid back.
The strength of the liquid circuit returns to the main cylinder, acting on the valve double effect and slightly compresses the spring, the liquid then passes through the periphery of it.
Pipes
The pipes can be:
Rigid or
They are formed by tubes of copper, brass or steel. They must be resistant to oxidation and corrosion. Put fixed to the frame or to the bodywork.
Flexible or
They are called patch cords. Connect the dots with movements during the march and is mounted between the frame and the wheels, axles and chassis and the front or rear.

Elements assistants
These are elements that apply to the main brake system, as explained, to improve their performance, increase security and make it more comfortable in their management. These are:

• braking limiter
Overview
For the braking of a vehicle is conducted in an effective way, it is necessary to implement the wheels on a couple resistant important without locking the wheels. The adhesion of the wheels to the ground state is a function of soil, tires and the applied load on the wheels.
When slows sharply a vehicle, the kinetic energy of the vehicle is transferred to the front wheels, while the rear is aligeradas load. We therefore applied a significant burden on the front axle relative to the load applied on the rear.
As the grip is a function of the load, it will increase by the front wheels and decrease in the rear.
For an effective and safe braking, it is necessary to vary in the same proportion the braking effort exerted on the rear wheels in relation to the front.
This device consists of a body. In his travels inside a valve to be supported on a spring git.
The brake fluid enters the limiter on his bottom and exits to address the bombines rear wheels of the two side holes (D and F).

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Functioning
When stepping on the brake pedal to get a slight braking, the brake fluid passes through the edge of the valve and the pressure that comes to bombines of the rear wheels, is identical to that of the front wheels.
You want to get rapid braking of the vehicle, the pressure of the liquid act on the bottom of the valve, and overcoming desplazándola action of the spring and obstruct the rear pipes. The pressure on the rear wheels is thus limited.
When the weight of the rear can vary considerably, limiters are used variables, which acted as a function of load. Its operation is more or less effective, depending on the height and position of the chassis and suspension.
• Compensator braking
It depends on your point of application. It is classified as:
Or Sobrepesores: system applied to the front brakes. They have the mission of amplifying the pressure supplied by the master cylinder.
Or Depresores: applied to the rear brake system. They are mandated to reduce pressure on the elements frenantes subsequent to prevent the wheels from locking.
• Brake relief or security
The hydraulic circuit with a main pump of a piston brakes, as described above, has the disadvantage that a leak of brake fluid disabled the entire system with the attendant danger that this implies.

Different manufacturers solve this problem by providing the vehicle for a dual brake system, with a double main pump with a piston primary and secondary, and two independent circuits. Some of these systems are as follows:
Or circuits, front and rear, are separated with a piston for each circuit.
Or separation of the circuits is made diagonally: front wheel left to right rear and right front to left rear wheel. This system is widely used today.
One or twice piston master cylinder frenantes acts on the elements of the four wheels and the other piston and circuit acting only on the front wheels.
O A dual master cylinder piston acts on the two front wheels and a rear, and the other piston acts on the two front wheels and a rear wheel. Each front disc brake is actuated by two pairs of pads.
• Serbo-brakes
It serves to reduce the effort that the driver must apply for operating elements frenantes. It installs servofreno necessarily between the brake pedal and the pump. It has an unshakeable position.
Whatever the type, servofrenos are always designed so that the effort of the driver may be exercised directly on the circuit brakes in the event of default assistance system (Servo).

Functioning
In resting phase
The valve is open. The valve is closed. The cameras, anterior and posterior receive depression engine (intake manifold) and the spring pushes the piston back.
In phase activated
The valve is closed. The valve is open. The camera is back to the atmospheric pressure in the anterior chamber, depression engine, therefore, there is an imbalance, the pressure compresses the spring and multiplies the effort exerted on the pedal.

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• Decelerador electrodinámico (electric brake) (figs. 23 and 24)
Also called retarder or retardant. This type of brake operates only when the engine is running and as a complement to the service brake.

Functioning
The retarder operates without friction or garrisons, thanks to the principle of eddy current.
Two discs of mild steel (rotors), operated directly by the transmission of the vehicle, rotating magnetic field created by electromagnets solidarity chassis (coils), and are powered by wiring the vehicle.
The retarder is operated from the driving position, a lever by uniting serving the battery of the vehicle with electromagnets.
Four independent circuits excitation allow the gradual establishment of the pair braking. They, above all, to stop on long pending, in order to download the service brake to avoid the phenomenon of fading. To produce a reduction in speed there is friction between the fixed and variable component. The brake is electric intercala in the transmission of the vehicle upon leaving the gearbox and differential or close to going under the chassis of the same. It is used in heavy vehicles, as a third brake assistant. There is therefore a brake stop, but could stop the vehicle.
• Decelerador hydrodynamic (hydraulic) (figs. 25)
It is a retardant to a projected flow of oil, the rotor on the stator.
Its mission is to transform the kinetic energy into thermal oil. The heat generated is largely absorbed in the heat exchanger, which is essential for the proper functioning of the retarder.
The control and maintenance of oil will be in accordance with the manufacturer’s instructions.
The retarder on the inside wearing a crankcase and two concave disks with blades faced. One of them, the stator, coupled staring at the rack and the other is attached to the rotor shaft.
The system is activated by a lever with several positions either through the brake pedal. There is no friction during operation mechanic.
By actuating the retarder is sent oil into the crankcase which contains the rotor and the stator. By rotating the rotor drives an oil pump to the stator where the energy absorption and the reaction produces the rotor braking in the transmission system.

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• Decelerador on the exhaust manifold (figs. 26 AND 27)
The mission of this system is to get the braking effect, to make the engine as a compressor, absorbing kinetic energy that takes the vehicle. Its use is equivalent to a reduction in the gearbox.
By operating the piston gradually, the air pressure cylinder circuit activated cutting injection and the cylinder valve command of strangulation, located at the outlet of the exhaust manifold, retaining exhaust gas and the ongoing effect compressor in the engine.

Braking System inertia
The mission of the braking system of inertia is to curb the trailer when it slows the tractor.
Its use has been reduced to light caravans or trailers.
At 8 represents the set of arms and lever system.
Functioning
The bar generally is the very spear hitch, and is mechanically connected to the trailer brake drums. When pulled the tractor trailer, the spear separates the drum pads, and when it slows, its own inertia of the trailer makes the bar moves forward, shortening the distance and pushing on the brake blocks forced into touch with the drum , as indicated by the arrows. The more abrupt deceleration of the vehicle is a tractor stronger the effect on the bar and consequently stronger braking on the trailer.

Anti-lock Brake System or ABS (9, 30 and 31)
The mission of the anti-lock system is to allow use maximum power braking in a position to bond very critical, automatically regulating the braking force with an acceptable degree of slippage between the tire and the road, giving preference to the stability and maneuverability directional connection the braking distance.
They prevent blockades of the wheels, even in icy slopes, shortens the braking distance, eliminates the uneven tire wear and avoid braking effect on the scissors between the vehicle and the trailer.
Overview
Basically, the ABS system, has the following elements:
– Electronic Control Unit.
– Group modulator (Solenoid).
– Cylinder command (hydraulic or pneumatic system).
E – Pedal (hydraulic or pneumatic system).
PS – catchers revolutions (Sensor-wheel polar).

Captador revolutions
What constitutes the sensor and wheel polar reporting to the control unit of the rotational speed of each wheel.
Modular Group
What are the solenoid mainly adapting the bombines pressures on the brakes, according to the orders received by the control unit.
The braking system is a group that unites hydraulic solenoid through the pump with cylinders of the brakes.
In pneumatic braking device is composed of independent solenoid.
The solenoid can get into the cylinders of brakes:
Reducing or pressure.
Maintaining or pressure.
Or communication with the circuit braking.
Electronic Control Unit
You must perform the following functions:
Or receives signals from sensors on the wheels (sensor, wheel-polar).
Or signals are analyzed.
Or are calculated slides wheels and accelerations or decelerations.
Send or the solenoid (modulation of the braking pressure).
Performs or checking system, leaving it totally or partially inoperative, in the event of failure, alerting the driver with witnesses.
Functioning
The ABS is an electronic system that automatically corrects the braking force of each wheel (or axis) depending on the level of adhesion it finds.
The electrical impulses generated by induction into the collector of the wheels (sensors) are transmitted to the electronic control unit, where they are constantly evaluated.
When the unit detects a tendency to lock the wheel, orders electrovalve begins modulation of pressure in the cylinders of the brakes.
This makes it possible to obtain a modulation wheel braking effective, with a minimum slippage.
The witness operating system stays on when the vehicle speed is less than 7 km / h. Or 15 km / h. If you carry a semi-trailer coupling, and will go off to overcome these speeds.
In case of a breakdown of the ABS system is cancelled it and the vehicle can continue to operate using the classic command system running.
When available vehicle and trailer or semitrailer, the ideal situation is that both have ABS.
System pneumatic brakes
The pneumatic brake systems used for operating the air pressure allows to obtain large braking forces. The compressed air is generated by a compressor, which is moved by a strap that transmits motion from the crankshaft. It is used in large trucks and buses carrying capacities, which for braking, to be fitted with the system that they can develop powerful braking.
The facility consists of systems and circuits which are described in 2:
Or feeding system:
? It supplies.
? Regula.
? Retains.
? Stores air pressure.

System Utilization
? Generates braking forces.
Or control system:
? Check pressure from certain circuits.
? Tip of the existence of a pressure drop at some point.
The installation of service and emergency brakes, it is composed of the following channels:
Circuit or food. .
Or circuit number 1 .- service brakes front of the vehicle and the trailer emergency.
Circuit or number 2 .- service brakes front of the tractor and trailer service.
Or circuit number 3 .- parking and emergency brakes on the rear axle of the tractor and auxiliary services.
Or circuit brake with remote control of the trailer.
• Description
Compressor mono
Purpose
The compressor is used for the production of high pressure air.
Functioning
Air absorbed by the bat through the intake valve is compressed by the piston on its way forward and sent the calderín through the exhaust valves.
Taking oil for lubrication compressor makes the circuit of the vehicle engine lubrication.

Valve automatic filter
Purpose
The pressure regulator, air filter and safety valve is a valve switching that works automatically. It regulates the pressure in the calderín air. Moreover, this valve is responsible for cleaning the air produced by the compressor (carbonized particles of oil, water, etc.).

Valve antifreeze
Purpose
Feeding with alcohol vapor to the circuit, avoiding, in this way, that could freeze the water on it.
It has two positions:
Position or summer.
Position or winter.

Drier air
Installed after the pressure regulator or in combination with it.
During phase connecting the regulator, the moist air passes through a granular formulation which absorbs moisture.

Valve triple protection circuit
Purpose
The valve triple protection circuit is designed especially for the protection of circuits doubles by compressed air brake, emergency brake and parking.
The valve triple protection circuit is placed before two tanks of compressed air dual circuit brake service, distributing compressed air from the pressure regulator.
In case of failure of one of the circuits brake blocks of compressed air at this circuit, only fueling the circuit intact.

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Automatic purge valve
Purpose
Purge automatically water from condensation in the tanks of compressed air.
In the brake circuit, the compression process leads to condensation of water vapor content in the air, which affects the safety and smooth operation of the facility (freezing water in the valves, cameras and acceleration of the processes of oxidation ).
This condensation, due to the cooling air from the compression is greater in areas furthest from the compressor, especially in deposits where cooling is greater due to the expansion of air.
In order to evacuate as quickly as possible such condensation, it uses an automatic purge valve, rather than the conventional manual pipe at the bottom of the reservoirs.

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Valve pedal double
Purpose
The valve is a double-pedal device whereby the driver simultaneously regulates the braking effort on the axles front and rear of a truck, and controls the brake system on a trailer or a trailer.
The dual brake valve consists of two concentric bodies, fed by two circuits and independent body mandated by a single push, which allows for a great progressive and removes the differences between the efforts and response times in the two circuits in use.

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Pressure Valve amplificadora
Purpose
The amplificadora pressure valve is installed on the trucks provided for coupling trailers and semi-trailers back by compressed air, in order to ensure that vehicles towed curb an instant before the tractor. This effect is achieved valve amplificadora pressure to send a signal pressure higher than that received by the truck brake cylinders.

0
Valve relay
Purpose
The relay valve allows rapid loading and unloading of air brake chambers and pipes, acortándose times responses in applications braking to avoid that the air has to make its journey from the valve pedal.

1
Valve manual parking brake
Purpose
Provides or evacuate the air to control the parking braking and auxiliary relief, in certain situations.

2
Cylinder membrane or plunger
Purpose
Beaming forces pressurized air to the brake pads for the actuation of the brakes.
They may be membrane cylinders or piston or cylinder combined.

3
Valve trailer brake
Es una válvula de paso de aire que, a voluntad del conductor, comunica los circuitos de freno de vehículo tractor y remolque.

4
Cabezales de acoplamiento
La unión del camión-remolque se realiza a través de dos cabezas de acoplamiento.
Están instaladas de modo que no pueda existir equivocación en su acoplamiento. Los acoplamientos en las instalaciones de doble conducto, no son intercambiables.
Los cabezales disponen de una válvula de forma que permite el paso del aire del vehículo tractor al remolque, y no a la inversa cuando están ambos vehículos desacoplados

Elementos de control
Para la lectura de las presiones en los circuitos, se indican mediante manómetros dobles, para los dos circuitos: de alimentación y freno de servicio.
El dispositivo de alarma avisa al conductor de una baja o pérdida de presión en determinados circuitos y puede ser: luminoso o acústico.

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Circuito de alimentación
Este circuito comprende: el compresor , la válvula automática con filtro (reguladora) , válvula anticongelante (opcional) y válvula triple de protección .

La alimentación del circuito se hace por un compresor monocilíndrico, que envía el aire a través de la válvula reguladora a los calderines de servicio, pasando por la válvula distribuidora (triple de protección).
Cuando se ha llegado a la presión máxima de servicio (7’5 Kg/cm.), la válvula reguladora descarga a la atmósfera el aire que produce el compresor y no se reconexiona hasta que la presión ha bajado de 6’5. Esta válvula incorpora un mecanismo de seguridad que abre entre los 9 y 11 Kg/cm. (presión excesiva).
Circuito número 1: freno de servicio delantero del vehículo tractor y emergencia del remolque
En este circuito se dispone de un calderín de servicio con capacidad de 40 litros, en el que va montada una válvula automática de purga, que cumple la misión de eliminar el agua condensada en el calderín .

Circuito número 2: freno de servicio trasero del vehículo tractor y freno de servicio del remolque
Hay una bifurcación de alimentación a la válvula relé , y salida de ésta a las cámaras de freno de servicio de los cilindros traseros.
En este circuito se dispone de otro calderín de servicio, en el que va montada una válvula automática de purga.

Circuito número 3: frenos de emergencia y estacionamiento en el eje trasero del vehículo tractor y servicios auxiliares
En este circuito todas las canalizaciones hasta la válvula de mando se encuentran constantemente bajo presión. Dispone de:
o Dos válvulas de rebose . Una para toma de servicios auxiliares y otra para toma de los accionamientos de caja de cambios.
La misión principal de estas válvulas es que, en caso de avería de los circuitos auxiliares, se conservaría en los calderines de servicio una presión máxima igual al tarado de las mismas, presión más que suficiente para varias frenadas normales del vehículo.
o Por lo tanto se comprende que son válvulas de seguridad en la instalación de frenos.
o Una válvula de mando (tipo todo o nada). Se monta en todos los vehículos que tengan frenos de cilindros por actuador con emergencia y estacionamiento.
Su misión es frenar o desfrenar el vehículo.
o Una válvula de retención (antirretorno). La misión principal de esta válvula es independizar los circuitos de la válvula de mando y de protección de los demás.
o Llave de paso , al cerrar ésta, se independiza el circuito de presión constante del vehículo tractor, con el calderín de servicio del remolque.

Circuito de freno con mando a distancia del remolque
o Válvula mando (freno remolque). Es del tipo progresivo; dependiendo del ángulo girado por la palanca transmite mayor o menor presión.
Sirve para dejar frenado el remolque (sin desenganchar del tractor) en estacionamiento o bien para, en marcha, frenar exclusivamente con el remolque, mejorando así la estabilidad direccional del conjunto tractor-remolque.

Sistema hidroneumático
Se emplea en vehículos ligeros industriales. Se instala en vehículos con circuito de aire a presión que se combina con un circuito hidráulico.
En este caso el aire comprimido sirve de asistencia o ayuda al conductor cuando acciona los frenos.
Se disponen de distintos circuitos:
o Mando neumático para instalación hidráulica de los frenos delanteros y traseros.
o Mando neumático para la instalación hidráulica de los frenos delanteros.
Al accionar el pedal de frenos, la válvula doble dosifica el aire a presión a la cámara o cámaras neumáticas (dependiendo del sistema), produciendo el accionamiento de los cilindros principales hidráulicos, que transmitirán su presión hidráulica hasta los cilindros de ruedas.
Mantenimiento
Como norma general se deben seguir las instrucciones dadas por el fabricante.
Se debe comprobar:
o El nivel de líquidos de frenos.
o El estado general de las canalizaciones.
o Fugas de líquido en la bomba principal, servo o bombines.
o La eficacia de la bomba principal.
o La eficacia del servo-freno.
o El estado de las pastillas y zapatas.
o Las superficies de los discos o tambores.
En los sistemas neumáticos:
o Fugas de aire.
o Agua en los calderines.
o Depósito anticongelante.
o Filtro de aire.
o Filtro de secado.
o Tensado de la correa y nivel de aceite en el compresor.
o Acoplamiento para el remolque.