A spring design that achieves a low spring constant can be effectively created by incorporating an auxiliary air chamber. This allows for precise control of the spring’s stiffness, ensuring a consistent spring height in railway vehicles when used in conjunction with a height control valve. As a result, the platform height and the vehicle's hook height remain stable regardless of passenger load, maintaining a higher overall vehicle body height. Unlike traditional coil springs, which cannot easily reduce their spring constant, air springs offer greater flexibility. By controlling the air volume, the spring height can be maintained consistently, enabling the use of a low spring constant while still ensuring stability.
Air springs also demonstrate excellent performance in blocking high-frequency vibrations. Unlike coil springs, which can transmit high-frequency oscillations due to their mass, air springs support the vehicle body using compressed air, eliminating pulsation and reducing the natural frequency of vertical motion. This leads to improved ride comfort. Additionally, the spring constant of air springs increases with load, but the change in natural frequency is minimal compared to coil springs. Practical applications have shown that designing air springs with a low spring constant through auxiliary air chambers significantly reduces vibration levels, resulting in smoother vehicle operation.
The practical application of air spring bogies began in the United States, where the Budd Company introduced the first commercial air spring vehicle. This early model featured a two-layer airbag structure, utilizing lateral stiffness for enhanced performance. The auxiliary air chamber was integrated into the bogie bolster, influencing later developments in Japan. Following World War II, as rail transport recovered, there was a growing demand for faster and more comfortable trains. Air spring bogies were further developed with the help of rubber manufacturers, leading to significant improvements in ride quality.
This paper presents a bogie equipped with a lateral vibration linkage mechanism known as a "pillar boom," replacing the traditional metal coil spring. It features a three-layer airbag-shaped air spring that functions primarily in the vertical direction, with the auxiliary air chamber utilizing space within the upper bolster beam. Initially, air spring bogies relied on orifices between the air spring and the auxiliary chamber to provide damping through airflow resistance. However, the non-linear flow characteristics of the orifice made it difficult to predict damping effectiveness. To address this, hydraulic dampers were initially installed in parallel with the air spring, similar to conventional designs. Later, some systems, like those developed by Sumitomo Metal Co., Ltd., eliminated oil dampers entirely, relying instead on carefully calibrated orifice sizes determined through vibration testing.
Center Valve,Rotation Type Center Valve,Sanitary Center Valve,Beer Racking Arm Valve
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