Kabushiki Kaisha Fujikoshi

Kazuo Araki

Ikuo Tochizawa

An AC or DC solenoid for operating a hydraulic or air valve, or another machine comprises a means provided at one end of an armature for reducing the effective cross-sectional area of a magnetic path extending through the armature and a yoke when the armature and a stationary core have a distance therebetween which is smaller than a predetermined fraction of the full stroke of movement of the armature. The solenoid is further provided between the armature and the stationary core with a means permitting them to be brought into axially overlapping relation to form a section of leakage flux therebetween. According to another aspect of the invention, there is provided novel means for securing a solenoid of the armature in tube type to a valve body. The improved solenoid has a small size, a long life, and superior performance without causing any excessive attraction over a given small stroke and generating any large noise.

Solenoid

An improved solenoid apparatus for operating valves such as hydraulic/air valves or other mechanical devices including a pressure proof tube which is wholly or partially nonmagnetic and has one end connected sealingly to a stationary core, an armature slidably mounted in contact with the inner face of the pressure proof tube, and a coil assembly comprising substantially a yoke and a coil encompassing the pressure proof tube. A cylindrical magnetic ring enclosing a part of the stationary core and a part of the pressure proof tube in the vicinity of the end face at the attracting side of the stationary core is inserted between the stationary core and the coil assembly the one end of the magnetic ring protruding axially over to the armature side, whereby the solenoid can be used either with alternating or direct current merely by replacing the coil assembly. When the solenoid is connected to an AC power source, there is no need to install a shading coil and therefore, the apparatus is low in cost and reliably endures impact loads.

Growing community of inventors

Tateyama, Japan

Kazuo Araki