DAMPER AND VALVE

摘要

A valve regulates fluid displacement in a damper assembly. The valve is placed between a portion of fluid at one pressure and regulates the passage of fluid through an aperture or passage (20) to a portion of fluid at a lower pressure by a blocking member (26) which moves to obstruct the aperture in accordance with a desired level of damping. The blocking member is, or is driven by, an electroactive device, such as a bimorph actuator formed of ferroelectric material. In one embodiment, the blocking member is a bimorph which covers the aperture, and is flexibly displaced by passage of pressurized fluid through the aperture. A controller provides an electrical actuation signal to move the bimorph toward or away from the aperture, augmenting or decreasing its closing bias to affect both the threshold flow initiation pressure and the rate of flow once the passage opens. Preferably the blocking member is a flexible piezoelectric assembly, which moves across a gap to provide a varying obstruction in the near field of fluid flow as the fluid moves through the passage. Preferably, a position sensor connected to the controller senses piston position, and the controller operates to energize the bender and to obstruct the opening or to further restrict flow if the piston position or its velocity is determined to lie above a threshold. This extends the useful range of the damper and may allow optimal stroke of the damper during all conditions of use, enhancing comfort while preventing bottoming out.