At present, road transportation has become the main mode of transportation in our country. As the main equipment of road transportation, semi-trailer trucks are composed of semi-trailer tractors and semi-trailers. They are widely used due to their advantages of strong specialization, large loading capacity and fast transportation.
Below we will start with the most basic classification of trailers and take you step by step to learn more about all aspects of trailers.
▎Tractor and trailer
A tractor is a general large truck or semi-trailer that is towed by tools between the front and the box, that is, the front of the vehicle can be separated from the original box and tow other boxes, and the box can also be separated from the original box and be towed by other vehicles. .
The front of the vehicle with driving capability is called a tractor, and the vehicle with no driving capability behind it is called a trailer, and the trailer is towed away by the tractor.
Classification of tractors
The tractor is the power source in the car-train combination, used to tow the trailer to realize the transportation operation of the car-train.
1. According to the trailer mode
Full trailer tractor: a tractor towing a full trailer. The rear beam of the frame is equipped with a towing hook, which is connected with the hanging ring on the trailer, and drives the trailer to travel, as shown in the figure (a) below.
Semi-trailer tractor: a tractor dedicated to towing semi-trailers. This kind of tractor generally does not have a cargo box, and is equipped with a tractor seat on its chassis. The traction seat bears the load of the front part of the semi-trailer, and locks the traction pin on it to drive the semi-trailer to drive, as shown in the figure (b) below.
Special trailer tractor: used to tow special trailers. This kind of tractor is usually connected to the cargo with a rotating pillow seat,
2. According to the drive type
The 4×2 tractor has a small traction force and is mostly used in high-speed trains.
The 6×4 tractor can increase the carrying capacity of the tractor seat
The 6×6 tractor has large carrying capacity, large traction and large gradeability, and is generally used for larger military vehicles
The 8×8 tractor is generally used on heavy-duty trains.
3. According to purpose
According to the purpose, tractors can be divided into cargo tractors, semi-trailer tractors and on-site tractors.
Cargo tractor: It can be used for both traction and cargo, and is used for full-trailer trains or special trailer trains.
Semi-trailer tractor: It is only used for traction and is used for semi-trailer trains. A tractor seat is installed on its frame to support and tow the semi-trailer.
Tractor used in the field: used in airports, railway platforms and ports and docks, and can tow semi-trailers or full trailers.
▎Classification of trailers
1. Classified by traction connection method
Full trailer: refers to a trailer with at least two axles. The hook on the tow bar is connected to the towing hook of the tractor. The tow bar has both traction and steering functions, and the trailer's load is fully borne by itself. According to the number of axles, full trailers can be divided into single axle, double axle and multi axle full trailers.
Semi-trailer: refers to a towed vehicle that has its axle (single axle or multiple axles) placed behind the center of mass of the vehicle (at uniform load) and has a traction connection device that can transmit horizontal and vertical forces to the tractor.
The traction connecting device on the semi-trailer usually adopts a traction pin, and the traction pin is usually connected with the traction seat of the tractor, and part of the load of the trailer is borne by the tractor through the traction seat. The support device is used to maintain the balance of the semi-trailer when unhooking.
