Tap trailer brake control: working principle, connection

Standard tap trailer brake control is used to control the brakes of the semitrailer when triggered, a similar system of the tractor. In addition, he is responsible for the automatic actuation of the brakes in case of critical pressure drop in the pipeline. Drive this node – combined type (one and two-wire). Consider the design features of the device and the connection device.

Brief description

Crane trailer brake control consists of the following elements:

• Pair control valve and the same single element.
• Two razoshelsya cranes.
• Couple connection heads.

Valve is responsible for managing the brakes of the semitrailer, directs compressed air from the input source to the subsequent customers, working either synchronously or separately. Two conclusions there is a command to increase the line pressure, and one counterpart goes the opposite effect, influencing the decrease in pressure when releasing air mixture by means of manual lever.

Check valve

Crane trailer brake control is equipped with a main valve, which consists of three sections, a large and a small piston with a spring. Average piston element has an inlet valve biasing spring to the housing socket.

The Other constituent parts of the considered details:

• Diaphragm.
• Discharge opening.
• Stock.
• Adjusting screw.

In the uninhibited position to the output parts is constantly supplied with compressed air. It acts on the diaphragm and the piston, holds it together with the stem in the lower position. This contributes to the increased area of the diaphragm. At the top of the piston group, located in the extreme upper position and the exhaust valve is separated from the seats. Inlet analog is in the closed position under the influence of the spring. One of the conclusions of the brake connects the control line with the atmospheric output with the help of unloading holes and stock.

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Operation of the valve when braking

Valve tap trailer brake control KAMAZ under braking delivers the compressed air from the sections of the device to the conclusions. From another output of the air reservoir the compressed mixture is fed to the control output then goes to the trunk part. There the air acts on the piston as long as it is below the upper pressure is balanced at the bottom. The upper piston operates under the force of air pressure and springs. It also needs to be balanced against the middle piston under the influence of identical factors. In principle, there is a General witness the action.

When you release the air compressed is discharged through the atmospheric hole faucet from the filled compartments. The pistons are under spring pressure and air mixture be in the upper position, while the stem piston moves down. The valve is detached from the mounts and connects the internal and external input.

Suitable for compressed air makes a separate move the rod with the piston up, and the large and small piston element down. Subsequent brake operation occurs on a similar principle.

When activated, a backup or auxiliary system of the truck compressed air is supplied through the atmospheric hole to manually return tap the action and goes out. The degree of pressure above the diaphragm decreases, reducing the force of the impact on work items. The saddle rests on the valve, separating the output pin with the atmosphere. Then the valve opens, informing between the output and the main highway.

Features

At the tap of the trailer brake control line pressure is injected to the moment when the force acting on the piston from the bottom, not on par with the influence applied to the aperture. This provides a servo valve work.

When the air compressed mixture is suitable to both the working conclusions, and the pressure in the compartment connected to the main system and the pressure value exceeds the value in the control output (20-100 kPa), is leading the action of the brakes. The magnitude of the required pressure set using the adjusting screw by screwing or unscrewing it.

Single protective flap

This element is used to maintain pressure in the air reservoir of the tractor in case of a critical decrease of this indicator in the supply line of the semitrailer. In addition, it prevents the leakage of compressed air from the system under emergency pressure reduction in the drive of the vehicle to prevent unauthorized braking of a hitch.

The Single valve adjusted to bypass air when the outlet pressure reaches 550 PA. The mixture enters through the conclusion in the working niche under the diaphragm, then – in the cavity before the valve. From there it goes to the output of the main highway. The amount of the required increased pressure is controlled by adjusting screw.

Razoshelsya crane

This item is involved in the crane operation the trailer brake control as follows:

• When necessary, blocks the pneumatic line, aggregating the tractor with towbar.
• If you set the handle of the fixture along the axis of the crane, pusher to the rod will be inthe lower position and the valve will be opened. The air is compressed through it and the appropriate output is sent from the vehicle to the semitrailer.
• When placing the handle across the skeleton of the displacement rod and diaphragm upwards under the air pressure and springs. The valve blocks the insights, sitting in the saddle. Air mixture comes from connecting the system to the atmosphere, which gives the opportunity to separate the connecting head.

The following is a schematic representation of the crane as well as basic symbols and components.

• A - device is not active;
• B — the open position of crane;
• 1 —output to the valve control air cylinder of the tractor via a single safety valve;
• II — the Main output of the trailer brake system;
• III — atmospheric output;
• 1 — spring mechanism;
• 2 — valve;
• 3 —aperture with a rod;
• 4 — a return spring;
• 5 — pusher with handle.

Head connection “palm”

These are the parts of the crane brake control trailer KAMAZ are also applied in systems of MAZ and «Ural». The elements of serve to consolidate the trunk dual circuit pneumatic drive vehicle truck and trailer. They represent the head of the valveless type, for sealing joints used rubber gasket. The unit also includes fasteners responsible for holding the parts in interlocked condition.

Single-wire system

In contrast to the two-wire tap trailer brake control, this structure consists of control valve, resubmitting analogue and connecting the L-shaped head.

Valve brake control with single-way drive runs through one line to be used as supply and control system. It should be noted that the valve operates on the pressure decrease in the main line, with the possibility of bringing the figure to atmospheric parameter. When the pressure drops, the braking coupling increases. To other parts of the crane are: the pusher with the diaphragm, the speed of piston type valves (inlet and outlet). Between themselves, they are aggregated by the connecting rod. Also there is a lower piston.

Work in a disinhibited state

In the inactive position, the air in compressed form is fed from a cylinder of the Parking brake system to the output, which is connected with the atmosphere by means of valve control. Under the influence of the power spring, diaphragm and the pushrod are located in a lower position. The exhaust valve remains closed, and the inlet analogue works open, letting the air out to a conclusion which aggregates to highway brake control with single-way drive.

Simultaneously, compressed air is supplied in a special cavity, pressure in which is equal. Given the fact that the area of the stepped piston, it moves up until it stops. When you reach the pressure in chamber brake line of the trailer in the order of 500-520 PA, the lower piston goes down and blocks the inlet valve. In disinhibited state, the system automatically maintained a pressure of 500 PA, which is slightly lower than the same parameter in the pneumatic drive of the truck.

How the system functions when braking?

When you activate the brakes of the tractor compressed air from the turbofan of the faucet goes to the valve single-tap trailer brake control MAZ. The mixture fills the plane under the diaphragm. After overcoming the spring force, the diaphragm is served up along with the pusher, the intake valve closes, the outlet member opens. The air goes into the atmosphere, bypassing the special conclusion, the pusher and the hole in the lid.

A Stepped piston performs a tracking action. If the pressure on the pin and in the cavity decreases, and decreases the force on the piston bottom. In the upper part of the element exposed to the pressure of the respective cavity, the identical effort in the second compartment. The hub, in turn, perceives the force from the first cavity. In the result, because of the pressure difference, the piston moves downwards, dragging the RAM, which is its seat and closes the outlet port. The subsequent pressure increase causes the full-release-air mixture from the main brake design trailer. The pusher is thus in its extreme lower position, the intake window is blocked, the exhaust element – opened.

Stateful mode

Connection tap trailer brake control imply the normal operation of all units of the device. One option when easing of the brakes of the tractor communicates with the atmosphere through the provided hole of the two-way drive valve. The pressure in the working chamber is reduced, and the aperture with the pusher is moved to its original position, blocking the outlet valve and opening the inlet element. The air in the compressed state enters the output and coupling system of the trailer, rastormazivate it.

L-shaped coupling head aggregates with line single-drive, automatically closing coupling system truck in the case of spontaneousseparation of heads, that can happen when raccept trailer. The head is equipped with a valve to block the action of the spring in a broken element, and operable connected to the head by means of a pin.

The valve of the trailer brake control Wabco

That such structures are equipped with trailers attached to cars “MAN”, “sale”, “Volvo”. There are several modifications of cranes. Consider the features of the node with the possibility of advancing.

Working brake the node is in the flow of air through the coupling head. Food passes through the output tap to the receiver of trailer. Simultaneously the piston under spring pressure goes down along with the valve. Opening the exhaust hole which connects with the working conclusions. After actuation of the brakes of the tractor compressed air mixture flows through the connection head into the chamber of the piston.

Crane trailer brake control “MAN” takes the after the closing of the outlet air from the receiver through the outlets to the cylinders. At the same time, the mixture goes into a special chamber forms a force on the valve. After the injection limit pressure valve opens against the compression spring. As a result, the air flows in the storage compartment, loading the lower part of the piston. After the summed up pressure in all chambers is reached, the piston is served up.

Automatic braking

Crane trailer brake control "Volvo" when you break the supply line receives a sharp decrease in pressure, causing the load is removed from the piston. Under the spring force, the piston moves up and the valve overlaps the exhaust hole. A piston part with a further displacement frees the intake window.

Using the findings of the pressure from the receivers fully supplied to the brake cylinders. When you open the trunk, tap the trailer brake control "DAF" works in a similar way as described above. This is due to the fact that the pressure in the supply design of the crane also decreases because of the leakage site after the start of braking of the tractor.

Fault

There are a number of issues that may reduce the effectiveness of the brakes. Kit for crane trailer brake control may be necessary in the following cases:

• After separation of the heads in the main line and the opening resubmitting crane air from it does not arrive to the vehicle.
• Open razorscale tap air mixture from the head to the trunk of the truck goes, but after connection of the elements of the tractor and spreader trailer feeding is terminated.
• When you activate the brakes the brakes on the car are working, and trailer no.
• In the case of when the head when braking, the air comes out.
• In the process of releasing the wheels of the tractor to respond, and on the coupling device remains in the locked state.