| 摘要 |
PURPOSE:To absorb an impact by utilizing the viscosity of a magnetic fluid by a method wherein the fluid is pressed against a pressure receiving plate by a pressure plate. CONSTITUTION:When a coil 2 is not energized, a plunger 3 is pulled to the right by a wire 12 and a pressure plate 6 and a pressure receiving plate 10 is separated from each other by a distance equal to the stroke of a plunger 3. In this case, as magnetic poles exist at both side corners of the outer periphery of the pressure plate 6, the inside corners of the outer periphery of the pressure receiving plate 10 and the inside corners of the central hole, the magnetic fluid 11 adheres to these corners in the form of a ring. When the coil 2 is energized, the plunger 3 is attracted to a core 1 and moves rapidly until it comes near its final attracted position. At the same time, the pressure plate 6 fits into a concave section 7a in a pressure adjusting chamber 7. Further, the magnetic fluid 11 adhered to the opposing inner surfaces of the pressure plate 6 and the pressure receiving plate 10 is strongly pressed until the plunger 3 reaches its final attracted position and flows into escape passages 7b, 7c and 7d. In this case, air is discharged from pressure relief valves 7b', 7c' and 7d' provided at the upper ends of the escape passages, respectively, so that the magnetic fluid flows, smoothly into the escape passages and the impact generating as a result of the plunger 3 running against the core 1 is absorbed completely due to the viscosity of the magnetic fluid 11. |
