| 摘要 |
PURPOSE:To prevent reduction in suction force at a great stroke by sealing magnetic fluid into the spaceing formed between an electromagnet and a plunger. CONSTITUTION:When a coil 13 is energized, a magnetic loop is formed and a plunger 15 is shifted to the left, and as a result, the volumn of a spacing 17 is reduced. Since a magnetic fluid 18 is not compressive, air 16c is compressed to generate pressur P, which is shifted to the left until the P is equal to F/S; where S is a crosssectioned area and F is a suction force of the plunger end face. When the conduction is suspended, the plunger is driven to the right by a force PS and performs a reciprocating motion by excitation or nonexcitation of the electromagnet 1. The following equation can be written in this case; F=1/2XU<2>XmuS/delta<2> where U is a magnet motive force across between end faces 11c and 15a, mu is a magnetic permeability and delta is a spacing in the end face. According to the above constitution, since the spacing is sealed with the magnetic substance having a great mu, a great force can be generated at a stroke greater than for the air when the spacing is measured constant. |
