摘要 |
<p>A dual volume air spring (5) for a truck suspension, which has an air bag chamber providing a variable volume (6) and a fixed volume chamber (7). The chambers are interconnected by a closable orifice (12). The air bag is provided with a post-like orifice closer (20) which is pushed into the orifice when the air bag (9) is sufficiently compressed ad withdrawn from the orifice when the air bag is not compressed. In normal operation the orifice is open and combined volumes of the chambers are available resulting in a low spring rate. The orifice closer (20) has an orifice closing portion (22) which is relatively pliant and a rigid or semi-rigid portion (21) which acts as a bump-stop when the pliant portion is substantially completely compressed. When the orifice is completely closed the spring has a high spring rate.</p> |