What Is Semi Trailer Suspension
Semi trailer suspension is a general term for all force-transmitting connection devices between the semi-trailer frame and the axle, which is used to transmit the force and torque acting between the wheels and the frame, buffer the impact force from the road to the frame or to the body, and reduce the vibration caused thereby to ensure that the vehicle can run smoothly.
Different Types of Semi Trailer Suspension
What are the types of semi-trailer suspension? Where is the air suspension?
In general, the suspension of semi-trailers can be mainly divided into four types:
1. Rigid Suspension.
The body chassis of the rigid suspension acts directly on the axle between the wheels, without springs as a buffer. It completely relies on the swing of the balance beam to maintain the relative balance of the front and rear axles when the road surface is uneven.
This kind of suspension is relatively rare at present because its shock absorption effect is very poor, and it is mainly used on lowbed semi trailers that carry goods at low speeds.
2. Steel Plate Suspension.
Also known as tandem leaf spring balance suspension, which is the commonly used leaf spring suspension. It is mainly composed of leaf springs, suspension supports, connecting rods, U-bolts, etc.
The biggest advantages of this kind of trailer suspension are low cost, high reliability, and easy maintenance. Because of this, steel plate suspension is currently used in the largest proportion of domestic semi-trailers with about 70-80%.
3. Single-point suspension.
That is, the common front and rear brackets of the leaf spring are reduced to a single bracket and connected to the car body, which can divide the force point into different axles so the bearing capacity is higher. It is generally used on heavy-duty trailers.
4. Air Suspension.
Also known as airbag suspension, its most notable feature is the airbag-type air spring. Compared with other suspensions, the air suspension has better cushioning force, which can effectively protect the cargo and improve driving comfort. In the transportation of precision instruments, hazardous chemicals, etc.
According to the technical conditions for motor vehicle operation safety, the 3-axle fence type and side wall type semi trailers must be equipped with disc brakes and airbag suspension to be successfully licensed or driven on the road.
Technology of Semi Trailer Suspension
A semi-trailer suspension assembly belongs to the technical field of semi-trailer suspension. It includes a front bracket, a leaf spring, a balance arm, a middle bracket, a rear bracket, a first leaf spring seat, and a second leaf spring seat. One of its characteristics is that the first leaf spring seat and the second leaf spring seat are respectively connected with the middle bracket and the rear bracket through the shock absorption device.
The upper part of the middle bracket is provided with a balance arm, which is connected with a leaf spring. The end of the leaf spring is provided with a clamping hook and limit blocks are installed on the inner wall of the upper part of both ends of the balance arm. A groove is designed in the middle of the lower end of the limit block. One end of the inner side of the groove is in contact with the clamping hook, and the outer end of the groove is clamped with the clamping hook.
The effect is that the suspension assembly has the advantages of good vibration damping effect, which prevents the end of the suspension from falling off and improves its service life and driving safety.
Disadvantages of Semi Trailer Suspension
At present, the suspension of semi-trailer adopts leaf spring balance suspension. Due to the influence of road roughness and the influence of alternating load generated in vehicle starting and braking conditions, the suspension bracket of semi-trailer will also be influenced by the action of alternating load. Under the repeated action of this alternating load, crack initiation, expansion, and sudden rupture may occur, which is a potential safety hazard.
Since the vibration of the vehicle during transportation will affect the quality and service life of the vehicle, in order to solve the impact of vibration, in the frame structure of the semi-trailer, the balance arm swings under different road conditions to reduce the impact from the wheels and suspension. Therefore, during the swinging process of the balance arm, the end of the suspension easily crosses the highest point of the arc surface and escapes from the balance arm. This can cause vehicle failures and accidents.
In summary, in order to improve the safety and service life of semi-trailer cargo transportation, it is necessary to have the most ideal structure of the existing semi-trailer suspension to achieve the effect of reducing vibration and solve the problem of the suspension end snapping out of the balance arm.