Many drivers, faced with the need to transport bulky cargo, wonder what exactly is called a trailer of a car and how it differs from other types of towed vehicles. In a broad sense, this term is understood to non-mechanicalintended for movement in a composition with a tractor. The main difference is that the trailer does not have its own engine, and its movement is completely dependent on the traction car.
The design of this device is developed taking into account high loads and road safety requirements. Understanding how a trailer is built is essential not only for its proper maintenance but also for safe operation on public roads. Traffic rules The technical requirements for such vehicles are clearly regulated and their violation may result in serious fines or emergencies.
In this article we will analyze in detail the main components and assemblies, from which the device of a modern car trailer is formed. You will learn about the role of the frame, the features of the chassis and the principles of the coupling mechanism that connects the tractor and the trailer device.
Classification and appointment of trailer devices
Before you delve into the technical device, it is worth determining what types of trailers exist, as their design can vary significantly. Classification It is usually made by the load capacity, number of axles and type of coupling. Car trailers, which are most often used with conventional cars, are divided into single-axle and biaxial models.
Uniaxial variants are more maneuverable and easier to control on the road, but have restrictions on the weight of the cargo transported. Dual-axle structures allow for the transport of heavier objects such as snowmobiles, quad bikes or building materials, but require more careful attention to load distribution. There are also specialized platform-trailerRefrigerators and onboard models.
The choice of a particular type depends on the tasks you plan to solve. It is important to understand that the device of the frame and suspension directly depends on the declared manufacturer of the load capacity. Using a trailer in violation of weight restrictions can lead to the destruction of key structural elements.
Frame and load-bearing elements design
The basis of any trailer is its frame. It is this element that perceives all the main loads that arise during movement, braking and maneuvering. The frame is a welded structure made of profiled-pipe or the channelers. The quality of welds and the thickness of the metal directly affect the durability of the entire product.
On the frame is installed body or platform, and all other components are attached. Modern models often use a tubular profile, which provides high strength at relatively low weight. The tubular frame is less susceptible to corrosion in the welded joints compared to the structures of an open channel.
After each heavy load trip, check the welded seams on the frame - microcracks can appear unnoticed, but lead to breakage on the way.
An important element of the carrier system are spars - longitudinal beams running along the entire length of the trailer. They provide the rigidity of the design. If the spangers deform, this can lead to a violation of the geometry of the wheels and rapid wear of the tires. Therefore, the condition of the frame requires regular visual monitoring.
Chassis: axles, suspension and wheels
The chassis is a complex mechanism that ensures smooth running and stability of the trailer on the road. The main element here is an axis (or bridge), which can be equipped with a spring or torsion suspension. Spring suspension It is considered more reliable and maintainable in conditions of bad roads, while the torsion one provides better smoothness.
The wheels of the trailer must meet the requirements of the traction vehicle manufacturer. Often the same tire size is used for the car and trailer, which makes it easier to replace the spare wheel in transit. The hubs of the wheels are equipped with bearings that require regular lubrication and maintenance.
☑️ Check of the running gear
Particular attention should be paid to the condition of shock absorbers (if they are provided by the design) and Silentblocks. Wear of rubber metal hinges can lead to the appearance of a characteristic knock and deterioration of handling. The table below shows the main types of suspensions and their characteristics.
| Type of suspension | Load capacity | Smoothness of course | Repairability |
|---|---|---|---|
| Resorbed | Tall. | Medium | Tall. |
| Torsion | Medium | Tall. | Low. |
| springy | Low. | Tall. | Medium |
Couple and breathing.
The breather is the forward-protruding part of the frame intended to attach the coupling device (trailer farcop). It is through this node that the traction force from the car is transmitted. The design of the breathed should be rigid to exclude yawing of the trailer when driving.
At the end of the breath is located coupling-headIt is worn on the car’s header ball. Inside the head is a locking mechanism that fixes the ball. There are different types of heads, but the most common models under the ball with a diameter of 50 mm. The reliability of the fixation is checked by a special indicator or visual control.
⚠️ Warning: Before starting the movement, always check if the coupling head lock is completely latched. Insufficient fixation can lead to uncoupling at high speed.
For safety, the coupling device is often equipped with a safety cable or chain. This element shall prevent the complete loss of the trailer in the event of a breakdown of the main coupling mechanism. The cable should be fixed on the frame of the car in a special way, excluding its sagging to the ground.
Electrical and lighting equipment
Safety of movement in the dark and in poor visibility conditions is ensured by the electric equipment of the trailer. I agree. Traffic rulesthe trailer shall be equipped with position lamps, stop lamps, direction indicators and retro-reflectors.
The connection of the electric circuit between the car and the trailer is carried out through the socket and plug. A 7-pin or 13-pin connection scheme is standard. Violation of contacts or oxidation of connectors leads to failure of lighting devices, which is a common cause of fines.
Electrical problems
If only the turns flash and the stop lights do not burn, check the mass on the trailer body. Often oxidized contact area fixing the lamp to the metal.
The wiring should be protected by corrugated tubes and securely fixed to the frame to prevent rubbing and breakage. The use of poor quality insulation materials can lead to short circuits and fire. Regular inspection of the integrity of the insulation is a mandatory part of maintenance.
Brake system and stabilization systems
For trailers with a gross mass of more than 750 kg, the presence of its own braking system is a mandatory requirement. Most often, inertial brakes are used, which are activated when pressing the brake pedal of the car. When the tractor slows down, the trailer rolls on it by inertia, and a special mechanism through the cables dilutes the brake pads.
Inertial run-in It requires the right setup. If the brakes are too sensitive, the trailer can block the wheels of the car. If too weak, the stopping distance will increase significantly. Adjustment is made by changing the tension of the cables.
Inertial brakes do not work when reversing without unlocking, so manoeuvres often require you to manually disconnect the brake system.
Modern systems may also include wear sensors for brake linings and mechanisms for automatic clearance adjustment. Servicing the brake system includes replacement of brake fluid (in hydraulic systems), checking the condition of drums and pads, as well as lubrication of moving elements.
⚠️ Note: The operation of a trailer with defective brakes is strictly prohibited. This poses a direct threat to the life of the driver and other road users.
Maintenance and care
For the trailer to serve long and reliably, it needs regular maintenance. It includes not only washing, but also checking the condition of all nodes. Particular attention should be paid to corrosion protection, as the frame is constantly exposed to moisture, dirt and reagents.
Wheel hub bearings require periodic lubrication or replacement. Depending on the design, lubrication can be made through oils or require removal of the hub. Ignoring this point leads to a jamming of the wheel and a possible fire.
- 🔧 Regularly lubricate the hinges of the coupling mechanism and cables.
- 💡 Check all lighting devices before each trip.
- 🔩 Control the tightening of the wheel nuts after the first 50 km of run.
- 🛡️ Treat the frame with anti-corrosion compositions at least once a year.
Timely detection of minor malfunctions avoids expensive repairs in the future. Careful attitude to the condition of tires, mounts and electricians guarantees the safety of your trips.
Can I use a trailer with a damaged frame?
The operation of trailers with cracks or severe corrosion of the frame is prohibited. This can lead to the destruction of the structure and loss of cargo on the road, which will entail an emergency situation.
How often should the bearings of the hubs be lubricated?
It is recommended to lubricate the bearings every 10-15 thousand kilometers of run or once a year, whichever comes first. If water enters the hub, the lubricant should be replaced immediately.
Do I need to register a homemade trailer?
Yes, any trailer, regardless of whether it is factory or homemade, must undergo the registration procedure with the traffic police and have the relevant documents and license plate.
What to do if the trailer starts to wag on the track?
Vibration or wagging is often caused by improper loading. The cargo should be shifted closer to the drawer so that the coupling ball accounts for about 5-10% of the weight of the cargo. Check the tire pressure as well.