| 摘要 |
PURPOSE:To absorb the shock noise of a plunger generated when attracted to a main magnetic pole simultaneously augmenting the attractive holding force as a completely closed magnetic circuit by a method wherein a plunger is attracted by AC simultaneously adsorbing magnetic fluid material to a main magnetic pole and a sub-magnetic pole in DC magnetic field. CONSTITUTION:When a main pole 8 is supplied with AC, a plunger 3 attracted to the main coil 8 starts to fall while compressing a resetting spring 19. At thim time, the secondary AC voltage induced by a sub-coil 9 is rectified by a diode 17 while a main magnetic pole 5 becomes a magnetic field supplied with both AC and DC. At this time, a piston rod 15 is slidingly falls to push up magnetic fluid material 11 contained in a chamber 12 above the surface of the main magnetic pole 5 through a channel 13. The DC shunt magnetic flux density of a sub-magnetic pole 7 is the more increased the nearer the plunger 3 approaches to the main magnetic pole 5 while the magnetic fluid material 11 is more intensely adsorbed hitting the plunger 3 with the shock adsorbed by the viscosity thereof generating no noise at all. |
