| 摘要 |
PURPOSE:To improve recovery speed of a plunger keeping the noise suppressed by a method wherein a means with which the inside and the outside of a bobbin are continuously connected when the plunger is projected out of the bobbin for a certain length. CONSTITUTION:A plunger 29 is projected out of and drawn back into a hole 22 provided to the center of a DC solenoid 21. The portion 29a of the plunger 29 toward the backside of the hole 22 has a smaller diameter. A scraper 28, whose cross section is approximately V-shape and whose lip part 28a at its tip faces the backside of the hole 22, is provided to an annular groove 27 formed by a front panel 26 and a bobbin 24. When the plunger 29 is attracted to Fb direction by the magnetomotive force of the coil 21, the tip part 28a is pressed against the circumference of the plunger 29 and the pressure in the hole is increased so that the speed of the plunger is reduced and the sound when it hits a fixed core becomes small. When the plunger is drawn out to Fa direction, air enters the hole 22 easily and if the plunger is projected over a certain length, because of the smaller diameter portion 29a, the scraper 28 does not work at all so that the plunger recovers quickly. |
