Is the general construction of a half-wheeled vehicle a sloppy one?

A semitrailer is a common freight vehicle with a unique design: the axle is mounted behind the vehicle's center of gravity and connected to the tractor via a specialized coupling device (the kingpin). This connection not only transmits the horizontal pulling force of the vehicle during travel, but also withstands vertical loads.

A semitrailer has no power system of its own; all its driving force comes from the tractor in front. When the tractor begins to move, the kingpin transmits power to the semitrailer, propelling it forward.

Classification of Semitrailers

Components of a semitrailer

What are the components of a semitrailer? Generally speaking, a semitrailer can be divided into the following structural parts: the frame, superstructure, kingpin, suspension system, running gear, electrical system, support system, protective devices, and trailer accessories.

1. The frame is the primary structure for loading cargo and consists of beams, welded I-beams, supporting crossbeams, connecting crossbeams, side beams, locks, kingpin connection devices, and panels.

2. The superstructure, including sidewalls and gantry, assists the frame in loading cargo. 

3. Kingpin: This is the critical component that connects the semitrailer to the tractor and bears the traction force that propels the trailer forward.

4. Suspension system: This is the device that connects the frame and axle. It primarily supports the load and mitigates the impact of dynamic loads on the vehicle and cargo. It can generally be categorized into four types: plate suspension, single-point suspension, air suspension, and rigid suspension. Each type of suspension differs in performance, and the appropriate suspension should be selected based on the vehicle's intended use.

5. Running gear: This primarily refers to the axle system, rims, and tires. Its primary function is to bear the load and maintain vehicle movement, supporting and distributing the load between the frame and wheels. Currently, leading domestic axles include BPW, Fuhua, Dayong, and York. Dayong axles offer the best value, offering reliable quality and a reasonable price, making them highly popular with customers.

6. Electrical system: This consists of cables, air lines, and lighting. Its primary functions are lighting, braking, and safety warnings.

7. Support system: This supports the trailer when the semitrailer is unhitched.

8. Protective devices: These are generally categorized as side and rear guards. 

9. Trailer accessories, such as toolboxes, spare tire racks, plug-ins, and other small accessories.