Solenoid valve in the cavity are confined in different locations are open through holes, each hole to have a different pipeline, is the valve chamber in the middle, the two sides is the electromagnet, which side of the magnet coil power body will be Which side to attract, through the control valve to the movement of files or live in a different row leakage of oil hole, and into the hole is often open, hydraulic oil will enter a different pipeline row, and then through the oil pressure to promote The Pistons just oil, piston rod drive again, the Pistons led pole mechanical action. This by controlling the current electro-magnet to control mechanical motion.