JPS6223061Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a magnetic pole for an electromagnetic device suitable for application to an electromagnetic device used for focusing a beam of ions, electrons, etc. or an electromagnet device that generates a traveling wave magnetic field at the center of the magnetic pole. .

The present inventor previously proposed an electromagnetic device for beam focusing or for generating a traveling wave magnetic field as shown in FIG. In the figure, reference numeral 1 indicates a magnetic pole made of soft magnetic material with a rectangular cross section, which has through holes 2 on both upper and lower surfaces.
is provided. Reference numeral 3 denotes a ring-shaped (including elongated) magnetic field generating coil, which is inserted between the magnetic poles 1 and generates a magnetic field between the upper and lower through-holes 2 by passing current through the coil 3. This electromagnetic device is easy to assemble, can be easily manufactured even in confined spaces, and can be provided at a relatively low cost.

However, if the magnetic pole is made of a highly conductive soft magnetic material such as a silicon steel plate, for example, as shown in FIG. . More fringing occurs as the distance to the through hole 2 increases, and in locations close to the through hole 2 on both the upper and lower surfaces, as shown in FIG. 1A, eddy currents occur and the magnetic pole 1 generates heat. When the heat generation increases, the magnetic permeability of the magnetic pole 1 decreases, making it impossible to stably generate a high magnetic field, and in the worst case, there is a risk of burnout of the coil 3, which is extremely problematic.

In view of this, the present invention has been developed to eliminate the drawbacks of the conventional magnetic pole by providing a plurality of cuts around the through hole to permanently suppress heat generation with almost no effect on the magnetic properties. The main purpose is to make suggestions.

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 3 is a perspective view of a magnetic pole showing an example of the present invention.
Components that are the same as those in the example in FIG. 1 are designated by the same reference numerals and their explanations will be omitted. Reference numeral 5 indicates a plurality of notches provided radially from the center of the through hole 2. The width of the cut may be accurate enough to be machined, and since it is formed radially from the center of the through hole 2, it has almost no effect on the magnetic properties. Eddy currents are then suppressed due to the formation of the notches 5. Note that the notch 5 can be formed symmetrically with respect to the center of the through hole 2.

The magnetic poles and coil (not shown) having such a configuration can be incorporated and used, for example, as an electromagnetic device for focusing an ion beam or the like. In addition, by stacking several layers of magnetic poles with such coils inserted between them and connecting an alternating current source to the coils, a traveling wave magnetic field is generated. It can also be used as a place to separate bodies.

As described above, according to the present invention, since the magnetic poles are provided with radial notches, it is possible to significantly suppress the heat generation of the magnetic poles, and there is no adverse effect on the magnetic properties. The practical effects are significant.

[Brief explanation of the drawing]

FIG. 1A is a plan view showing an example of a conventional magnetic pole, FIG. 1B is a side view thereof, and FIG. 2 is a diagram for explaining fringing that occurs in the magnetic pole. FIG. 3 is a perspective view of a magnetic pole showing an example of the present invention. 1...Magnetic pole, 2...Through hole, 5...Notch.

Claims (1)

[Scope of utility model registration request] In an electromagnet device, a magnetic field generating coil is inserted between a magnetic pole made of a soft magnetic material having a rectangular cross section and a through hole provided at the center of the plane of the upper and lower surfaces, and a magnetic field is concentrated at the end of the through hole, around the through hole. A magnetic pole for an electromagnet device, characterized in that a plurality of notches are provided radially from the center of the hole.