Modern rail vehicles have been developing constantly toward the direction of high-speed, lightweight and low noise.Because of their advantages,air suspension systems are widely applied. Not only do air springs improve the rolling forces of the vehicle,but also provide more comfortable riding condition and more quiet cabin environment. In addition,it has simplified the construction of the carriage.These advantages have helped the designers to fulfill the requirement to reduce the total vehicle weight on city rails and subway .Air spring is playing a critical part in the word.
Generally speaking,it takes three stages for rail vehicles to adopt air springs :
•Due to its vertical characteristics, the vertical moving stability is achieced for vehicle system;
• Air spring has the characteristics of vertical and horizontal moving,which makes it possible to abolish the two -suspension device, simplify the veer frame structure;
• Because of its 3D features of large shift(including torsion),low landscape orientation stiffness,we are allowed to cancele the bolster,and realize the lightweight of two-suspension system thoroughly.