I believe many friends first saw the middle axle trailer, the first reaction was: "this is full trailer originally!"
In fact, the whole trailer is mainly composed of cars, bridges, bogies and traction devices. The front axle, bogie and traction device are combined as a whole, which can be turned with the driving direction of the tractor; in addition, the traction device can move up and down, and that is precisely because of this, the tractor only plays the role of traction. Bear the weight of trailers, so trailers can be stably "standing" on the road without relying on tractors.
Of course, the disadvantages are obvious. Reversing is very troublesome. The driver's driving skills are extremely demanding, even more difficult than the semi-trailer reversing several orders of magnitude.
However, the number of all trailers is very rare now, after the 90s of last century, with the improvement of the road facilities and the development of the highway, the problem of the poor stability of the whole trailer is becoming more and more obvious.
The middle axle trailer is more stable and simple to reverse the vehicle
The middle axis is very similar the full trailer , but it is totally different. First of all, its axle is concentrated in the middle of the car. Secondly, it does not have bogies, and the traction device can not move up and down. Because of this, a part of the weight of the middle axle trailer must be borne by the tractor. Once the tractor is left, the trailer will lose its center of gravity and "fall down" on the road.
On the whole, the middle axle trailer is more like a semi-trailer, so it will be much easier than reversing.
Characteristics of a middle axle trailer
1, the traction device can not have the ability to move up and down like the whole traction device.
2. The position of the axle is close to the center of gravity of the trailer
3, the weight of the traction device delivered to the tractor is not more than 10% of the total weight of the trailer or 10000N.
Then compare the features of the full trailer:
1, the axle is distributed at the front and rear ends of the car body, and the parking is stable.
2, front axle with bogie, with the steering of the tractor.
3. The vertical direction of the traction device can be moved.
4, bear the whole weight of the whole vehicle.