| 摘要 |
<p>PURPOSE:To obtain a solenoid dust cover which has a tough structure and less volume change, by shaping the end face of a sealed dust cover into a crimped polygon, and shifting the trough of the crimp in the direction of outer diameter at the time of shifting from set to operation, thereby causing the volume change to occur only in the outer diameter direction. CONSTITUTION:When an electromagnetic coil 6 is excited, a plunger 8 is attracted in the direction F, whereby a dust cover 9 having one end thereof fixed to the plunger 8 is axially compressed. Hereupon, since the ridge 9C and the trough 9D constituting a hinge are universal, the end face becomes flat while the height l becomes zero, so that the virtual angle between each ridge 9C and trough 9d becomes zero. At this time, the length L2 of the trough 9D, or the outer diameter is apparently extended from the point P to the point PL as seen from the top, thereby increasing the volume. With this, the volumes of the dust cover 9 at the expansion and contraction times readily become equal, except that the end face of the dust cover varies in shape in response to expansion and contraction of the plunger 8.</p> |
