Most of them are hydraulic shafts in series. All hydraulic suspension devices are divided into three groups: front (or rear), left and right, and oil pipes are connected in series to form three closed circuits, each of which is connected to the valve of the control box. The load triangle of the trailer cargo platform formed by the fulcrums A, B and C of the three circuits is called "three-point support", which enables the cargo platform to be stably supported on a plane. By adjusting a certain circuit through the control box, heavy-duty vehicle trains can safely pass through large transverse or longitudinal slopes; by adjusting all circuits, the piston of the hydraulic suspension device can be raised and lowered, and the cargo platform can be raised and lowered within a certain height range, so as to facilitate the passage of certain circuits. Overpass or air obstacles, and can be leveled with the loading and unloading platform of large cargo, which is convenient for loading and unloading operations.
In addition, when a heavy-duty vehicle train equipped with a multi-axle tandem hydraulic suspension device passes through the uneven road surface, each wheel is subjected to different reaction forces due to the different positions of the ground, so that the piston of the hydraulic suspension device is lifted up and down, and the oil The fluid flows between the series circuits, while maintaining the load balance of each hydraulic suspension device unchanged. This way the tires on either axle are not overloaded.
