KR20090040827A - Array magnet assembly method - Google Patents

Abstract

The present invention relates to a method of assembling an array magnet, and to a method of assembling an array magnet capable of arranging permanent magnet pieces in a cylindrical shape safely and simply using a jig and a substitution method. According to the present invention, first insert the center frame for the array magnet in the central axis of the jig and the outer frame in the center of the jig. Insert the non-magnetic substitution blocks between the two frames to form an array magnet once, and then to replace the pieces by replacing the pieces one by one to assemble the pieces magnets. The magnet inserted into the frame is fixed with a screw, and the magnet's attraction and repulsive force can be used to finely adjust the magnet's position while tightening or loosening the screw.

Description

Assembly Method for Assembling Magnet Array

The present invention relates to a method of assembling array magnets used in nuclear magnetic resonance spectroscopy and magnetic resonance imaging techniques. Specifically, a method of assembling permanent magnets into a cylindrical frame safely and simply using a jig and a substitution method. It is about.

It is known that the nuclei that make up a molecule have a so-called Nuclear Spin Angular Momentum and its accompanying magnetic moment. In other words, an atomic nucleus with spin angular momentum behaves like a small magnet. When a strong static magnetic field is applied to the nuclear magnet from outside, the nuclear magnetic energy level when the strength of the magnetic field is zero splits into several levels. These levels are called the Zeman level of nuclear spins.

If you apply a strong magnetic field to an assembly of several such nuclear spins, the nuclear spins will be distributed according to Boltzmann statistics at the Zeman level in thermal equilibrium. When a magnetic field oscillating in the direction perpendicular to the static magnetic field is applied to the collection of nuclear spins, a transition occurs between the nuclear spin levels, indicating a unique response to the nuclear spin system. Nuclear Magnetic Resonance (NMR) spectroscopy is to find out various information about the nuclear spin system by observing the response.

In nuclear magnetic resonance spectroscopy, when a superconducting magnet is used, a strong static magnetic field of 1T or more is applied. Superconducting magnets have the advantage of generating a strong magnetic field of the desired intensity, but they are relatively expensive compared to other magnets and require the use of expensive liquid helium for operation. In order to solve this problem, the use of permanent magnets is being devised. Permanent magnets are relatively inexpensive and do not require the use of liquid helium. However, it is difficult to create a uniform magnetic field whose magnetic field strength exceeds 1T with a bipolar permanent magnet.

However, Dr Halbach has found that arranging several permanent magnets in a special shape can generate a large magnetic field. According to Dr. Halbach's method, when several permanent magnets are placed in the form of a hollow cylinder, the strength of the magnetic field in the hollow space of the cylinder increases as the ratio of the outer radius to the inner radius increases. However, since the number of magnets actually constituting the cylinder is limited, usually by assembling an appropriate number of magnets to produce a cylindrical shape.

1 is a schematic diagram of a cylindrical array magnet consisting of eight permanent magnets. This is S.J. Lee, J.M. Kenkel, V.K. Pecharsky, and D.C. Jiles, J. Appl. Phys. vol. 91, pp. 8894-8897, (2002). In Fig. 1, the arrow indicates the magnetization direction.

However, the problem with the array magnet is that the assembly is not easy. Equal pieces of permanent magnets are basically magnets with strong individual magnetic forces and magnetized in different directions. Therefore, not only safety is a problem during the assembly process due to the strong force pushing and pulling or twisting each other, but also it is difficult to maintain the assembled cylindrical shape. In particular, with the development of magnetic materials in recent years, the strength of the magnetic field is increased, the problem is more serious. Therefore, the situation is required to assemble a safe and simple arrangement magnet.

Accordingly, an object of the present invention is to provide a method of assembling an array magnet which can safely and simply arrange the permanent magnet pieces in a cylindrical shape.

Another object of the present invention is to provide a method of assembling an array magnet that is easier to maintain the assembly shape of the array magnet.

Still another object of the present invention is to provide a method of assembling magnets which can adjust the homogeneity of magnetic fields by finely adjusting the positions of the permanent magnet pieces constituting the array magnets.

To this end, the present invention is a method of assembling the array magnet inserted between the center frame and the outer frame, each of the pieces having the same shape as the sculpture magnet, but without magnetic substitution blocks between the center frame and the outer frame Inserting in; Sequentially pushing the fragment magnet toward the substitution block to replace the substitution blocks between the center frame and the outline frame with the fragment magnets; It provides a method of assembling magnets comprising the step of fastening the screw to the screw hole formed in the outer mold to fix the piece magnets with the screw.

In addition, the present invention is a method of assembling the arrangement magnet inserted between the center frame and the outer frame, the magnets, the central portion corresponding to the outer frame, the upper surface is formed in the middle of the central portion, and the center portion Preparing a jig having a central axis; Fitting the center frame to the central axis and fitting the outer frame to the central portion; Inserting substitution blocks each having the same shape as the sculpture magnet but not having a magnet between the center frame and the outer frame; Separating the array magnet into which the substitution blocks are inserted in place of the fragment magnets from the jig; Sequentially pushing the fragment magnet toward the substitution block to replace the substitution blocks between the center frame and the outline frame with the fragment magnets; And fastening the outer surface of the engraving magnets by fastening screws to the screw holes formed in the outer mold to fix the engraving magnets with the screws.

In the arrangement magnet assembling method of the present invention, the piece magnets may each be a permanent magnet pieces as a trapezoidal cross-section or a trapezoidal shape of one side arc, the pieces magnets are the same in shape but different magnetization direction It is preferable.

In addition, in the arrangement magnet assembly method of the present invention, the center frame is a cylindrical shape, the outer frame may be a cylindrical shape of the inner surface of the polygonal or circular shape according to the shape of the magnets.

The arrangement magnet assembly method of the present invention may further comprise adjusting the position of the pieces of magnets by tightening or loosening the screw fastened to the outer frame.

On the other hand, in the arrangement magnet assembly method of the present invention, one side of the periphery of the jig can be formed in the discharge portion corresponding to the shape of the sculpture magnet, in this case the step of replacing the substitution blocks with the sculpture magnet And positioning the array magnet so that the one substitution block is on the outlet, and then pushing the fragment magnet toward the substitution block from the upper side so that the one substitution block is inserted into the outlet and the fragment magnet is inserted. It may be a step.

In addition, a separation groove may be formed at one side of the periphery of the jig, and the separating of the array magnet from the jig may include separating the array magnet using the separation groove as a support point of the lever. .

The method of assembling the arrangement magnet according to the present invention can assemble the arrangement magnet by arranging permanent magnet pieces in a cylindrical shape safely and simply without a special assembly machine using a simple jig, and it is easy to maintain the assembling shape of the arrangement magnet, and the arrangement magnet. The magnetic field can be controlled by finely adjusting the positions of the permanent magnet pieces.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, in describing the embodiments, descriptions of technical contents that are well known in the technical field to which the present invention belongs and are not directly related to the present invention are omitted. This is to more clearly communicate without obscure the core of the present invention by omitting unnecessary description.

On the other hand, in the accompanying drawings, some components may be exaggerated, omitted, or schematically illustrated, and the size of each component may not fully reflect the actual size. Like reference numerals refer to like or corresponding elements throughout the accompanying drawings.

2 is a plan view of an array magnet according to an embodiment of the present invention, Figure 3 is an exploded perspective view of the array magnet according to an embodiment of the present invention.

2 and 3, the array magnet 10 is an assembly in which a plurality of pieces of magnets 11 are assembled between the center frame 12 and the outline frame 13. The piece magnets 11 are pieces of permanent magnets, each of which is a cube having a trapezoidal cross section. However, the cross section of the carving magnet 11 is not necessarily limited to the trapezoidal shape, and may be changed into various shapes. For example, the side contacting the outer frame 13 may be a cube having a trapezoidal shape (not shown) made of an arc. Each piece of magnet 11 is the same shape, but the magnetization direction is different from each other as shown in FIG. The array magnet 10 may be composed of a suitable number of pieces of magnets 11, such as 8, 16, 32, 64.

The center frame 12 is a cylindrical shape having a predetermined diameter, the outer frame 13 is a cylindrical shape of the inner surface is a polygonal or circular shape according to the shape of the magnets 11, the outer surface is a circular shape. If the inner surface of the outer frame 13 is polygonal, the shape corresponds to the number of the magnets 11. That is, in the example of FIG. 2, since the trapezoidal shaped magnets 11 are all eight, the inner surface of the outer frame 13 forms an octagonal shape. In addition, when the inner surface of the outer frame 13 is circular, the number of pieces of magnet 11 is not limited. Although not shown, the inner side of the outer frame 13 forms a circular shape when the trapezoidal shaped magnets 11 are formed in an arc contacting the outer frame 13.

Therefore, when the engraved magnets 11 are sandwiched between the center frame 12 and the outer mold 13, each of the engraved magnets 11 forms a fixed point at least three points. Accordingly, the sculpture magnets 11 can maintain the assembled shape of the array magnet 10 while the translational and rotational movements by the strong attraction force and repulsive force between each other is suppressed.

On the other hand, several screw holes 14 are formed in the side surface of the outer mold 13, and the screws 15 are fastened into the holes 14. That is, the screw 15 is inserted into the screw hole 14 from the outer surface of the outer mold 13 to press the outer surface of the magnet magnets (11). Therefore, the magnets 11 may be tightened toward the center frame 12 to form a complete array magnet (10). It is preferable that at least two screws 15 are fastened to each piece magnet 11, for example, three screws in a horizontal direction and four screws in a vertical direction may be fastened.

In particular, the screw 15 not only functions to maintain the assembly shape of the array magnet 10 by fixing the pieces of magnets 11, but also to finely adjust the position of the pieces of magnets 11 to adjust the strength of the magnetic field. It also plays a role. That is, the fine movement toward the center is possible by tightening the screws 15, and the fine movement toward the outside is made by repulsive force between the pieces of magnets 11 by releasing the screws 15.

The arrangement magnet 10 has been described above. Hereinafter, the assembling method of the arrangement magnet 10 will be described. 4A to 4H are perspective views sequentially illustrating a method of assembling the arrangement magnets according to the exemplary embodiment of the present invention.

First, the jig 20 (jig) is prepared as shown in FIG. 4A. The jig 20 used for assembling the array magnet (10 in FIG. 3) is generally circular, and the upper surface of the center portion 21 is lower than the upper surface of the peripheral portion 22. The inner face of the central portion 21 corresponds to the outer face of the array magnet outline frame (13 in FIG. 3). Therefore, when assembling the array magnet 10, the outer mold 13 is fitted to the center portion 21 of the jig 20 fit. A central axis 23 is formed in the middle of the central portion 21, which is a portion into which the center magnet frame 12 (Fig. 3) is fitted. In addition, the discharge portion 24 corresponding to the shape of the magnet (11 in Fig. 3) is formed on one side of the peripheral portion 22 of the jig 20, and the separation groove 25 is formed on the other side.

When the jig 20 is prepared, the center frame 12 is inserted into the central axis 23 as shown in FIG. 4B, and the outer frame 13 is fitted into the center portion 21 as shown in FIG. 4C. Subsequently, the replacement block 30 is inserted into the center frame 12 and the outer frame 13 to assemble the same. The substitution block 30 is an object having the same shape as the sculpture magnet 11 but without magnetism. Substitution blocks 30 are assembled in the frame (12, 13) as a completed array magnet 10 in place of the piece magnet (11).

Subsequently, after separating the array magnet 10 having the replacement blocks 30 assembled therein from the jig 20 as shown in FIG. 4D, one replacement block 30 is discharged (FIG. 4E). Position the array magnet 10 above 24a of 4a. Then, when one of the pieces of magnet 11 is pushed toward the substitution block 30 from the top, one of the substitution blocks 30 is discharged toward the discharge part 24 while the magnets of magnets 11 are inserted into the molds 12 and 13. As another example, as shown in FIG. 4f, one replacement block 30 may be first removed, and then a piece magnet 11 may be inserted. When the array magnet 10 is separated from the jig 20, that is, when the central shaft 23 is pulled out from the center portion 21, when the separation groove 25 is used as a support point of the lever as shown in FIG. 4H, the array magnet ( 10) can be separated. Subsequently, as shown in FIG. 4G, the magnets 11 inserted into the molds 12 and 13 are fixed with the screws 15.

The method described above may be called a so-called substitution method. By using the substitution method to replace the substitution block 30 with a piece of magnet 11 one by one can be assembled safely and simply the array magnet (10). The order of substituting the magnet 11 is not significant, but when the position of the first magnet is 12 o'clock, the position of the second magnet is 6 o'clock, the third is 3 o'clock or 9 o'clock, yes The first one is preferably assembled at 9 o'clock or 3 o'clock. After replacing all of the substitution block 30 with the engraving magnet 11, it is possible to finely adjust the position of the engraving magnets 11 while adjusting the screw 15 as a whole.

So far, the method of assembling the arrangement magnet according to the present invention has been described. In the present specification and drawings, preferred embodiments of the present invention have been disclosed, and although specific terms have been used, these are merely used in a general sense to easily explain the technical contents of the present invention and to help the understanding of the present invention. It is not intended to limit the scope. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention can be carried out in addition to the embodiments disclosed herein.

For example, the discharge portion 24 of the jig 20 is not a position as illustrated in the figure, but corresponding to the position of the replacement block 30 in the form in which the array magnet 10 is fitted to the central axis 23. Can be formed. In this case, it is possible to replace the replacement block 30 with the engraver magnet 11 while keeping the rotational position at that position without having to separate the array magnet 10 from the jig 20.

The array magnet produced by the array magnet assembling method of the present invention can be used for nuclear magnetic resonance (NMR) spectroscopy, magnetic resonance imaging (MRI), etc., a sensor using nuclear magnetic resonance spectroscopy or magnetic resonance imaging, It can be applied to a sample inspection device.

1 is a schematic diagram of a cylindrical array magnet consisting of eight permanent magnets.

2 is a plan view of an array magnet according to an embodiment of the present invention.

3 is an exploded perspective view of an array magnet according to an embodiment of the present invention.

Figures 4a to 4h is a perspective view showing in order a method of assembling the arrangement magnet according to an embodiment of the present invention.

Claims (8)

In the assembling method of the array magnet in which the magnets are inserted between the center frame and the outer frame, Inserting substitution blocks each having the same shape as the sculpture magnet but not having a magnet between the center frame and the outer frame; Sequentially pushing the fragment magnet toward the substitution block to replace the substitution blocks between the center frame and the outline frame with the fragment magnets; Fastening a screw to a screw hole formed in the outer mold to fix the piece magnets with the screw; Array magnet assembly method comprising a. In the assembling method of the array magnet in which the magnets are inserted between the center frame and the outer frame, Preparing a jig including a central portion corresponding to the outer frame, a peripheral portion whose upper surface is higher than the central portion, and a central axis formed in the middle of the central portion; Fitting the center frame to the central axis and fitting the outer frame to the central portion; Inserting substitution blocks each having the same shape as the sculpture magnet but not having a magnet between the center frame and the outer frame; Separating the array magnet into which the substitution blocks are inserted in place of the fragment magnets from the jig; Sequentially pushing the fragment magnet toward the substitution block to replace the substitution blocks between the center frame and the outline frame with the fragment magnets; Fastening the screw to a screw hole formed in the outer mold to press the outer surface of the engraving magnets to fix the engraving magnets with the screw; Array magnet assembly method comprising a. The method according to claim 1 or 2, The piece magnets are permanent magnet pieces, each of which is a trapezoidal cross-section is a trapezoidal shape, characterized in that the trapezoidal shape is connected to the side of the outer frame is in contact with the outer frame. The method according to claim 1 or 2, The pieces of magnets are the same in shape, but the magnetization direction of the array magnet assembly method characterized in that different. The method according to claim 1 or 2, Wherein the center frame is a cylindrical, the outer frame is an array magnet assembly method, characterized in that the inner surface of the cylindrical to form a polygonal or circular shape according to the shape of the magnets. The method according to claim 1 or 2, Tightening or loosening the screw fastened to the outer frame to adjust the positions of the magnets; Array magnet assembly method comprising a further. The method of claim 2, One side of the peripheral portion of the jig is formed with a discharge portion corresponding to the shape of the sculpture magnet, In the step of replacing the substitution blocks with the fragment magnets, the arranging magnets are positioned such that one substitution block is on the discharge part, and then one of the fragment magnets is pushed toward the substitution block from the top, and the substitution block is one. Arrangement magnet assembly method characterized in that the step of allowing the piece magnet to be inserted while falling toward the discharge portion. The method of claim 2, Separation grooves are formed on one side of the periphery of the jig, Separating the array magnet from the jig, the array magnet assembly method characterized in that for separating the array magnet using the separation groove as a support point of the lever.

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