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AssigneesHitachi, Ltd., Hitachi Engineering & Services Co., Ltd.
InventorsAyumu Morita, Yasuaki Suzuki, Masato Yabu, Tooru Tanimizu, Yozo Shibata, Takashi Kadowaki
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An electromagnet composed of a coil, a movable iron core adapted to move on the center axis of the coil, and a stationary iron core provided so as to cover the upper and lower surfaces and the outer peripheral surface of the coil, characterized by a permanent magnet arranged in a gap surrounded by the movable iron core and the stationary core, wherein the movable iron core is attracted by the stationary iron core by a magnetic field created by the permanent magnet, thereby it is possible to solve a problem inherent to a conventional electromagnet such that a permanent magnet is directly energized in a reverse direction during release operation so as to cause demagnetization of the permanent magnet. That is, since the permanent magnet is arranged in the gap surrounded by the movable iron core and the stationary iron core, the magnetic filed can be prevented from affecting upon the permanent magnet, thereby it is possible to provide an electromagnet having a long use like and a high degree of reliability with no demagnetization of a permanent magnet.
An electromagnet composed of a coil, a movable iron core adapted to move on the center axis of the coil, and a stationary iron core provided so as to cover the upper and lower surfaces and the outer peripheral surface of the coil, characterized by a permanent magnet arranged in a gap surrounded by the movable iron core and the stationary core, wherein the movable iron core is attracted by the stationary iron core by a magnetic field created by the permanent magnet.
An electromagnet composed of a coil, a movable iron core adapted to move on the center axis of the coil, and a stationary iron core provided so as to cover the upper and lower surfaces and the outer peripheral surface of the coil, characterized in that a nonmagnetic protrusion is provided to the stationary iron core on a side where the movable iron core is inserted, the movable iron core is composed of a plunger and a steel plate fixed to one end part of the plunger, an end face of the plunger and the stationary iron core, and the steel plate and the protrusion are opposed in the same direction, and a permanent magnet is arranged in a zone surrounded by the plunger, the protrusion, the steel plate and the stationary iron core.
An electromagnet composed of a coil, a movable iron core adapted to move on the center axis of the coil, a stationary iron core provided at opposite end surfaces and the outer peripheral surface of the coil, a power source for applying current to the coil in forward and reverse directions, wherein the movable iron core is moved toward the stationary core when the current is applied to the coil in the forward direction, characterized in that:
Dependencies are inferred from the claim text.