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In an electromagnet switch, a stationary iron core is composed mainly of a base part and a disk part. The base part is faced to a plunger and the disk part is forcedly inserted and fixed to a boss part formed in the base part. The disk part is composed of a metal plate of ferromagnetic substance (ir

In an electromagnet switch, a stationary iron core is composed mainly of a base part and a disk part. The base part is faced to a plunger and the disk part is forcedly inserted and fixed to a boss part formed in the base part. The disk part is composed of a metal plate of ferromagnetic substance (iron plate) and another substance plate (made of resin or rubber and the like, for example,) of a smaller spring constant or a larger damping coefficient than that of the metal plate. The metal plate and another substance plate are laminated. Another substance plate absorbs or reduces the impact force when the plunger is electromagnetically attracted toward and collides with the base part. The propagation of a large impact noise or crashing sound is thereby suppressed, and as a result the impact noise can be reduced.

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What is claimed is: 1. An electromagnetic switch configured to control open/close of an electric contact, comprising: a magnet coil; a movable iron core movably contacted with the electric contact; and a stationary iron core configured to attract the movable iron core when magnetized by supplying a

What is claimed is: 1. An electromagnetic switch configured to control open/close of an electric contact, comprising: a magnet coil; a movable iron core movably contacted with the electric contact; and a stationary iron core configured to attract the movable iron core when magnetized by supplying a current to the magnet coil, the stationary iron core comprising: a base part faced in arrangement to the movable iron core; and a disk part of a cylindrical shape plate assembled to the base part, placed at one side of the magnet coil, and the disk part comprising: a metal plate of ferromagnetic substance; and another substance plate having one of (a) and (b): (a) a spring constant which is smaller than that of the metal plate; and (b) a damping coefficient which is larger than that of the metal plate; and wherein the metal plate and another substance plate are laminated. 2. An electromagnetic switch configured to control open/close of an electric contact, comprising: a magnet coil; a movable iron core movably contacted with the electric contact; and a stationary iron core configured to attract the movable iron core when magnetized by supplying a current to the magnet coil, the stationary iron core comprising: a base part faced in arrangement to the movable iron core; and a disk part of a cylindrical shape plate assembled to the base part and placed at one side of the magnet coil, and the disk part comprising a plurality of metal plates of ferromagnetic substance which are laminated, and at least one, but not all, of the metal plates having one of (a), (b), and (c): (a) a spring constant, which is smaller than that of the other metal plates; (b) a damping coefficient which is larger than that of the other metal plates; and (c) a coefficient of friction which is smaller than that of the other metal plates. 3. The electromagnetic switch according to claim 2, wherein at least a slit or a hole is formed in at least one of a plurality of the metal plates in order to reduce a spring constant or a damping coefficient of the disk part. 4. The electromagnetic switch according to claim 3, wherein one end of the slit or of the hole does not reach the outer periphery of the disk plate and formed within an outer diameter of the metal plate. 5. The electromagnetic switch according to claim 3, wherein the slit or the hole is formed in each metal plate, and the slit or the hole formed in all of the metal plates laminated make a penetrating hole in its lamination direction, and end terminals of the magnet coil are elongated toward an opposition direction to the disk part through the penetrating hole. 6. The electromagnetic switch according to claim 3, wherein the slit or the hole is formed in each metal plate, and the slit or the hole formed in all of the metal plates laminated make two penetrating holes in a lamination direction of the metal plates, and end terminals of the magnet coil are elongated toward an opposition direction to the disk part through the penetrating holes, and the two penetrating holes are formed in symmetry of the diameter of the disk part. 7. The electromagnetic switch according to claim 5, wherein a plurality of the metal plates in the disk part are laminated to each other regardless of a front surface and a back surface of each metal plate. 8. The electromagnetic switch according to claim 2, wherein the disk part is composed of a plurality of metal plates of ferromagnetic substance laminated, and a surface treatment or a lubrication treatment is performed on the surface of at least one metal plate in order to have a smaller coefficient of friction rather than the other metal plates. 9. An electromagnetic switch configured to control open/close of an electric contact, comprising: a magnet coil; a movable iron core movably contacted with the electric contact; and a stationary iron core configured to attract the movable iron core when magnetized by supplying a current to the magnet coil, the stationary iron core comprising: a base part faced in arrangement to the movable iron core, and comprising a plurality of metal plates of ferromagnetic substance which are laminated; and a disk part of a cylindrical shape plate assembled to the base part and placed at one side of the magnet coil wherein the base part is composed of the metal plate of ferromagnetic substance and another substance plate which are laminated, and the another substance is a material having one of (a) and (b): (a) a spring constant which is smaller than that of the metal plate; (b) a damping coefficient which is larger than that of the metal plate. 10. The electromagnetic switch according to claim 9, wherein a slit or a hole which penetrates toward the lamination direction is formed in at least one metal plate in order to reduce its spring constant or to increase its damping coefficient rather than that of the other metal plates. 11. The electromagnetic switch according to claim 9, wherein the surface of at least one metal plate is treated by either a surface treatment or a lubrication treatment in order to reduce its coefficient of friction. 12. The electromagnetic switch according to claim 1, wherein the base part comprises a plurality of metal plates of ferromagnetic substance which are laminated. 13. The electromagnetic switch according to claim 1, wherein the metal plates forming the disk part are fixed to each other. 14. The electromagnetic switch according to claim 9, wherein the metal plates forming the disk part are fixed to each other. 15. The electromagnetic switch according to claim 9, wherein the metal plates forming the base part are fixed to each other. 16. The electromagnetic switch according to claim 12, wherein the metal plates forming the base part are fixed to each other.