Semi trailer structure knowledge to be understood when purchasing semi trailer

Semi trailer structure knowledge to be understood when purchasing semi trailer

1.Frame and carriage

The frame of the semi trailer is a frame structure, and the longitudinal beam is high quality shaped I-steel or welded I-steel. The structure is made into a stepped shape to reduce the center of gravity;

The crossbeam is made of high quality steel plate or channel steel, and the connection between the crossbeam and the longitudinal beam is made of beam piercing structure, which increases the torsional strength of the frame.

The whole frame is assembled and welded on a special positioning platform, with reasonable structure, high strength and good performance.

The carriage is all metal structure, open on three sides, and the height of the rail board is 600mm, which can also be increased or decreased according to user requirements. The left and right rail board can be divided into front, middle and rear sections according to the length of the carriage, which is convenient for cargo handling.

2.Supporting device

The semi trailer adopts mechanical supporting device, whose role is to support the ground and bear the front load of the semi-trailer when the traction device is detached from the trailer.

The supporting device has two kinds of single action type and linkage type, mainly composed of the supporting disc, screw transmission mechanism, reducer and control handle, the commonly used model hanjiang, Baohua, Fuhua and other several.

Users can also choose other models.

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3.The suspension

3-1.Single axle semi trailer suspension

Single axle semi-trailer suspension adopts single axle spring suspension device.

The front and rear supports are made of high quality steel plate, and welded into one with the longitudinal beam, firm and reliable.

The leaf spring assembly is composed of main and auxiliary leaf springs. The main leaf spring is of thickened, heavy-duty type, with sufficient bearing strength.

3-2.Two-axle semi trailer suspension

The semi – trailer suspension adopts double – axle balanced spring suspension device.

The front and rear leaf spring suspension is equipped with a mass balance device in the middle, the trailer in any uneven road driving, can make the front and rear leaf spring deflection equal changes, to ensure the smooth trailer exercise.

3-3.Three axle (heavy duty) semi suspension

Three-axle (heavy duty) semi-trailer suspension adopts three-axle balanced spring suspension device.

There is a mass balance device in the middle of the front and rear leaf spring suspension, and the trailer is exercised on the uneven road, which can also make the deflection of the front and rear leaf spring change equally so that the car is buffered.

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4.The axle assembly

Axles are mainly composed of tires, axles, brakes and hubs.

FUWA, BPW, YORK, ZS10180 axles with excellent performance can be selected according to user requirements, or assembled by purchased assembly parts or parts. The axle head and axle body are made of high quality steel, and the axle body is integral or welded rectangular hollow section.

Tires often choose double money steel wire (nylon) tires, yellow Sea steel wire (nylon) tires.

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5.The braking system

Domestic brake device and imported brake device can be selected, and the trailer anti-lock braking system can also be installed according to customer demand.

Ordinary semitrailers are fitted with pneumatic brakes that act on all wheels.

When a car runs, the foot brakes are used.

Cars park with the driver’s brake.

At the same time, double pipe pneumatic braking system is adopted.

The semi-trailer is equipped with emergency relay valve and trailer storage cylinder, the right is a brake pipeline, through the connected valve to the tractor wet storage cylinder, regardless of whether the semi-trailer brake, it has been to the trailer storage cylinder inflation;

The left one is the control line, through the valve to tractor double cavity brake valve, control line airless at ordinary times, when braking, before the tractor brake valve will double cavity compressed air as a signal of circuit air storage tank, trailer emergency relay valve control and emergency relay valve will be due to the compressed air of the trailer air storage tank, sent to the trailer brake chamber.

6.Performance and features

The semi trailer equipped with double pipe pneumatic brake can be charged to the trailer air storage cylinder when braking continuously on long slope.

When the semi-trailer and tractor are off the hook accidentally or the gas pipe of the trailer leaks, that is, when the gas pressure is lower than the specified pressure, the trailer can brake by itself, and the rear brake circuit of the main car does not lose the braking effect.

Due to the high sensitivity of the emergency relay valve (10 Kpa), the pipeline layout is as close as possible to the trailer air storage cylinder and hanging axle, and a thicker air supply pipe is used.

This braking system has fast reaction time and good braking effect, which is beneficial to improve the power and fuel economy of the train. Especially, it can improve the braking strength of the trailer under the condition of long slope and frequent braking. It is an ideal braking system.

7.Structure and working condition of emergency relay valve

Emergency relay valve has the functions of inflating, safety braking (feedback braking), working braking and emergency braking, etc. It can replace the brake valve, distribution valve, gas brake acceleration valve and quick-release valve in the trailer braking system.

Emergency relay valve can shorten the trailer braking lag time, and can quickly release the brake, when the main and trailer inflatable pipeline damage (sudden accident) or artificially cut off air intake (driver operation), emergency relay valve can also make the trailer to achieve emergency braking.

8.Electrical system

Strictly in accordance with international 3C standard configuration.

This series dump semi trailer is equipped with international general circuit system suitable for tractor.

There is an electrical connection socket on the front beam of the frame, and a brake light, turn signal, parking light, reverse light, license plate light and triangle reflector are arranged at the rear of the frame, and a profile light, side light and turn signal are provided in front and on both sides.

All kinds of lamps and lanterns use voltage of dc 24V.

9.Trailer spray paint

After various treatments, the surface of the frame and carriage is sprayed with two layers of polyurethane topcoat, the coating is uniform, the adhesion is firm, and the luster is longer.

Pigment with advanced technology, variety, users can choose their own color.

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