What does a tractor-trailer mean? Does it mean a semi-trailer?

"Tractor-trailer" is a noun we often see, for example, in the driving test question bank, it is often seen that "the internship period of vehicles shall not be tractor-trailer", refers to the use of vehicles to drag the rear carriage of a behavior. In fact, in addition to the meaning of the verb, tractor-trailer also refers to a very widely used in the logistics and transportation industry.

Generally speaking, tractor-trailer refers to a type of vehicle with no driving capacity and mainly used to provide cargo loading space and bearing capacity. It relies on the traction power provided by the tractor in front of it to achieve driving. With the continuous development of the automobile industry, more and more traction models gradually emerged.

In terms of types, tractor-trailers can be mainly divided into the following categories:

1. Semi-trailer.

At present, the semi-trailer is the most widely used type of carriage in domestic road transportation. Its axle is installed in the rear of the carriage, so it cannot stand smoothly independently. It needs to take the front section of the carriage on the tractor-trailer, and keep upright by relying on the support force provided by the tractor-trailer. That is to say, the tractor requires a special traction saddle at the rear of the body, which is used to carry part of the weight of the semitrailer while providing traction power. After the semitrailer is detached from the tractor, special legs are needed for support.

Semi-trailer can be subdivided into flat plate type, gooseneck type, concave beam type, warehouse grid type, fence plate type, van type, container type, tank type, dump type, skeleton type and other types, its high speed stability is strong, the main hanging matching is simple, flexible application, strong bearing capacity, especially suitable for long-distance transportation, high-grade highway transportation, without steering device.

2. Full trailer.

Full trailer is the opposite of semi-trailer, the biggest difference is that full trailer can realize independent standing, its axle installation distribution can evenly bear the weight of the carriage, so even if not connected with the tractor can also be stable upright. The tractor in front only needs to provide traction power, so hook it up.

A typical full trailer is generally composed of frame, cargo platform (top), traction bar (frame), steering device, suspension, braking system, signal system, etc. Compared with the semi-trailer, the full trailer in the mountains or rugged road driving stability is stronger, this is mainly due to its traction bar or traction frame between the tractor can swing up and down. But relatively, the disadvantages are obvious, the stability is poor at high speed, easy to appear braking tail, traction frame fracture and other accidents, so it is mainly used for wharf, factory, port and other fields within the transport.

3. Middle axle trailer.

As the name suggests, the middle axle trailer refers to a kind of trailer whose axle is located in the center of gravity of the carriage. When it is separated from the tractor, it cannot support its own weight independently. It is mainly composed of the carriage, traction device and axle, and the connecting device with the tractor can swing left and right, but cannot move up and down.

Compared with other trailers, the middle axle trailer has the characteristics of low center of gravity, light weight, simple structure, etc., but because it is only suitable for use on high-grade highway, it is more suitable for fixed special line transportation. From the perspective of GB1589 standard, the middle axle trailer occupies certain advantages in the outer profile size, which may change the status quo of the dominance of semi-trailer with continuous development.

4, light traction trailer.

Different from other tractor-trailers, the main role of light tractor-trailer is not in the transport of goods, such as the trailer, that is, we often say RV, with passenger cars or light trucks can achieve traction, more extensive and convenient application.

Light tractive trailers can be subdivided into light tractive semi-trailers and light mid-axle tractive trailers. From the function point of view, the bearing capacity of light traction semi trailer is stronger, and the driving is more stable; The light tractor trailer with middle axle can stand independently and stably, but it is easy to offset when the carriage with middle axle carries a large load at high speed.

The above is the current domestic more common four types of tractor-trailer models. It is worth noting that no matter what kind of tractor-trailer, you must get the corresponding license qualification to drive, which requires A2 license for semi-trailer, full-trailer and mid-axle trailer, and C6 license for light tractor-trailer. Light tractor-trailers can be pulled with passenger cars, but currently only A2 drivers license is compatible with the C6 quasi-driving license. The rest of the drivers must apply for an additional license to drive tractor-trailers.

Although tractor-trailers vary, they all play a role in their areas of expertise. DARO Heavy Industry Group is the leader in the domestic trailer axle industry, with more than 20 years of axle research and development and production experience, has achieved good results in the "one-piece" trailer axle, lightweight axle, maintention-free trailer axle and other fields, reliable quality, affordable, to help owners improve transportation efficiency, reduce logistics costs, ensure safe operation.