SOLENOID

PROBLEM TO BE SOLVED: To provide a solenoid suppressing an influence of contamination and improving responsibility to actuation. SOLUTION: This solenoid 1 to drive a mother machine is provided with: a first bearing 7 and a second bearing 8 to slidably support a shaft 5 with a plunger 4 held between them; a plunger front chamber 74 defined between the first bearing 7 and the plunger 4; a plunger rear chamber 75 defined between the plunger 4 and the second bearing 8; a plunger peripheral passage 63 making the plunger front chamber 74 communicate with the plunger rear chamber 75; and a cylindrical cover 83 made of a non-magnetic material to surround the peripheral surface 41 of the plunger. The plunger peripheral passage 63 is defined around the cover 83 as a circular gap 55, and hydraulic oil of the mother machine is led to the plunger front chamber 74, the plunger peripheral passage 63, and the plunger rear chamber 75. COPYRIGHT: (C)2010,JPO&INPIT