JPH0627209A - Inspecting method for magnet - Google Patents

Abstract

PURPOSE:To provide an inspecting method for magnet in which center of magnetic field of a multi-pole magnet can be determined easily through measurement, shift from geometrical center can be measured, and defect of magnet material can be determined. CONSTITUTION:When magnetic fluid is encapsulated in a short tubular instrument 6 arranged substantially in parallel along the end face of a yoke 2 in a magnetic space 5 defined between the poles 3, 3' or a multi-pole magnet 1, the magnetic fluid is scattered by the magnetic field to the periphery of a vessel and a dark part 9 is formed in the center thus facilitating determination of the center of the field 5. Consequently, center of the field 5 of an actually operating magnet 1 can be measured easily and positively, assembling work of magnet can be carried out accurately, and reliability of all products can be enhanced by determining the center of the field of each magnet through simple inspection work at the time of mass production.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The disclosed technology belongs to the technical field of easily and accurately measuring whether or not a magnetic field formed by an electromagnet equipped in a precision machine or the like is in a designed state. .

[0002]

2. Description of the Related Art As is well known, modern society largely depends on highly developed science and technology, and in particular, various facility devices equipped with an electromagnetic system, as represented by so-called mechatronics technology, are widely used in various fields. Used in.

As a matter of course, in the high-tech technology equipped with the mechatronics function, it is indispensable that the assembly and installation state is accurate in order to exert the original function as designed, and especially, the nuclear power, semiconductor, These points are strictly required in advanced technologies such as medical treatment.

Thus, not only basic facilities for research and development, but also industrial facilities of companies, not to mention mm units, recently, devices having a definition of sub-micron units exceeding micron units. Facilities are indispensable, and various magnets, especially electromagnets are often used as seen in these various facilities, for example, high energy beam acceleration storage devices, and multipole magnets also improve the characteristics of the device to a high degree. It is used for all purposes.

Therefore, it is necessary to always maintain and maintain the high precision as originally designed regarding the behavior from various causes during the operation of manufacturing and assembling the electromagnet.

For this purpose, not only the initial manufacturing and assembling but also the material and performance of the yoke and pole piece of the magnet as well as the magnetic field from the assembled magnet can be formed as designed. For example, in a high energy beam acceleration storage device, many multipole magnets are used for handling a charged beam.
In order to increase the focusing efficiency of the charged beam and to effectively operate the charged beam, it is essential to specify the center of the magnetic field and match the magnetic field center with the theoretical orbit. Moreover, the technology that can be specified quickly has not been revealed.

For example, a means for performing a predetermined number of mappings in the space of the magnetic field is used, but basically it is necessary to make the magnetic field space into a mesh space of a predetermined number of divisions and measure the magnetic force at each mesh point. And, of course,
In order to improve the accuracy, it is necessary to take a large number of measurement points, that is, the number of mesh divisions, and there is a drawback that the work is extremely complicated, and it takes a long time and requires skill in measurement.

Even if the measurement is carried out, the active area of the element for measuring the magnetic field strength has a predetermined size, and even if the active area can be specified, the space with a large magnetic field gradient is measured. In this case, since the average value in the active area is shown, a problem occurs in the relationship between the measured value and the position of the indicated value.

In the case of a hall element, which is a typical measuring element, the temperature dependence of the indicated value is remarkable, so it is necessary to strictly control the temperature. It is essential to assemble and measure a probe with a large heat capacity.

The former cannot be carried out in one corner of the factory, and when the latter is selected, there is an upper limit of execution in order to reduce the size of the probe, and in the mode of a magnet with a small magnetic field space. The measurement itself can be performed only in a limited range, and the magnetic field center can be determined only with the accuracy of mm unit.

As a method for obtaining the center of the magnetic field of such a multipole magnet, an interpolation method by mapping the magnetic field distribution via the Hall element or the like is generally used, as described in, for example, Japanese Patent Laid-Open No. Hei 2
Although the technology of the magnetic field center measuring device as shown in the invention has been devised, it is not practical such as using a superconductor as a device, and the cost is high. It also has the disadvantage of not being practical in terms of maintenance and maintenance.

By the way, various techniques have been developed for measuring magnetic fields and using colloidal magnetic fluids in which magnetic particles of cobalt or the like are dispersed in silicon liquid or the like through a predetermined surfactant or the like. , For example, using the birefringence characteristic of a magnetic fluid, to obtain the magnetic flux density distribution by measuring the refractive index change due to the magnetic field strength change in the form of a phase difference,
JP-A-58-180963 JP Invention and JP-A-59-1
Although there is an invention etc., it is completely different from the technique of determining the magnetic field center in the magnetic field space, and can be diverted to the technique of determining the magnetic field center and determining the material and properties of the magnet that affect the magnetic field distribution. There is no defect.

Further, the spike-like pattern of the magnetic fluid in the magnetic field space is fixed by using a curing agent and taken out from the magnetic field space to observe the magnetic field distribution state, for example, the invention disclosed in JP-A-63-205586. Has also been developed, but there is a minus point that the magnetic field center cannot be easily and accurately measured as described above.

Further, a simple measuring instrument which is recently made of a thin and transparent magnetically permeable material, in which a magnetic fluid is enclosed in a short cylindrical container and the magnetized shape of a magnetic tape or the like can be directly visually observed. , Etc. have been developed, but there is no example used to detect singular points of the magnetic field in the magnetic field space or to judge the magnetic properties etc. from the magnetic field distribution pattern using such a measuring instrument. The method by interpolation of mapping of the magnetic field distribution via an element or the like is generally the only method.

Even if the theoretical magnetic field center can be calculated from the mechanical relative positional relationship in manufacturing and assembling multipole magnets, etc., due to various complex causes, the magnetic field center and the actual magnetic field center can be calculated. Does not always coincide with the above, and there is a problem that it hinders handling during operation.

[0016]

The object of the invention of this application is to define the center of the magnetic field of a multi-pole magnet, or the center of the magnet and the design center of the magnet, which is widely used in various precision mechanical equipments based on the above-mentioned prior art. Deviation, further, the technical problem to be solved in the determination of the material and alteration of the magnet that has an influence on the formation of the magnetic field is a technical issue to be solved, the determination of the center of the magnetic field by a rational method, although it is a very simple method, In addition, it is possible to reliably measure and judge the properties such as the deviation from the geometric center and the material defects that affect the magnetic field. It is intended to provide a method.

[0017]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the structure of the invention of the present application, which is based on the above-mentioned claims and has the above-mentioned object, is operated with extremely high accuracy.
When determining the center of the magnetic field of a multi-pole magnet installed in various equipment that requires operating conditions, basically a predetermined magnetic fluid is thin-walled transparent and magnetically permeable short cylindrical shape. Using a measuring instrument enclosed in a container such as, set in a magnetic field space in the multipole magnet along the end surface of the magnet in a substantially parallel posture,
Only the magnetic particles in the magnetic fluid in the measuring instrument, which are sensitive to the magnetic force of the magnet to be operated, are scattered around the container of the measuring instrument, and those that are not sensitive remain and are visually recognized. Since there is no, magnetic field particles near the magnetic field center remain and are made visible as dark spots, whereby the center of the magnetic field can be easily confirmed and the magnetic field center can be determined.
In addition, in order to record, take a picture of the measuring instrument having the dark point with a camera or the like, and measure the deviation from the geometric center via a three-dimensional shape measuring instrument or the like to determine the characteristics of the magnet. A part that can be inspected, and where the measuring device is set in a posture substantially parallel to a plane equidistant from the adjacent pole pieces, and the magnetic fluid does not change in the part where the magnetic force acts perpendicularly to the surface of the magnetic fluid. Even if it is slightly separated from the above, the attractive force acts on the pole and the electromagnetic particles move in the direction of the pole, a white line appears near the center, and the outline of the axial characteristics of the magnet can be determined, and the linearity of the white line is disturbed. The indirect and accurate identification of magnet materials and defects is made possible by means of the technical measures to ensure reliable inspection of magnets during manufacturing and assembly and for all mass-produced products. It is a thing.

[0018]

Embodiments of the invention of this application will be described below with reference to the drawings.

The embodiment shown in FIG. 1 is a mode in which the center of the magnetic field of a quadrupole electromagnet provided for focusing a charged beam in a high energy beam acceleration storage device such as an SR light generator is determined. The electromagnet 1 is integrally provided with four pole pieces 3, 3 ′ inside the ring-shaped yoke 2 so as to face each other, and the coils 4 and 4 are wound around each of them. A magnetic field space 5 is formed.

6 is a magnetic fluid type measuring instrument,
As shown in FIG. 3, a non-magnetic container 7 made of a thin transparent material such as an appropriate transparent resin is integrally attached to a thin aluminum plate on the back surface and a transparent resin panel on the front surface. Thus, a container is formed, and a magnetic fluid 8 in which, for example, magnetic colloid particles such as cobalt are dispersed in silicon liquid in a colloidal form is contained in a sealed state.

At the time of the filing of this application, the measuring instrument 6 is a commercially available instrument that allows the visual observation of the magnetized shape of the magnetic material as described above based on the density of the magnetic fluid.

Thus, although the center of the magnetic field 5 of the magnet 1 is roughly determined by the mapping interpolation method of the magnetic field distribution through the above-mentioned Hall element, it does not always coincide with the design position as mounting equipment. Not always, therefore,
When the high energy beam accelerating and accumulating device is operated, it is impossible to give a highly accurate effect to the convergence of the charged beam as designed. Therefore, as shown in FIG. 1, the measuring device 6 is used to determine the center of the magnetic field 5. , The pole pieces 3 and 3 ′ are set so that the centers of the yoke 2 and the measuring device 6 are substantially parallel to each other along the end surface of the yoke 2 via an appropriate magnetically permeable spacer or the like. The pole pieces 3, 3'are excited by energizing 4, 4, ... And a magnetic field 5 is formed.

Therefore, the magnetic lines of force pass through the container of the measuring device 6 and the magnetic particles in the magnetic fluid 8 are attracted by the magnetic force and concentrate around the container. However, as is well known, the magnetic force acts near the center of the magnetic field. In order not to do so, the magnetic particles are left as spots, and therefore, the periphery of the container becomes light-colored, the central portion becomes black, and it is determined that the black portion is the center of the magnetic field 5 in the cross section perpendicular to the axial direction. You can

Therefore, the center of the magnetic field 5 of the magnet 1 can be measured and determined by attaching an appropriate grid scale to the transparent resin plate on the surface side of the measuring instrument.

In this way, the center of the magnetic field 5 of the quadrupole magnet 1 can be accurately determined by the residual dark spot 9 of the magnetic fluid 8 of the measuring device 6.

Incidentally, the pole pieces 3, 3 '...
If there is a mistake in the connection of the coil 4 with respect to, the dark point will not appear because the polarity setting will be different,
Therefore, it is possible to promptly determine a connection mistake of the coil 4 or the like.

Further, as shown in FIG. 2, by setting a camera (including a television camera) 10 in a direction in which the measuring instrument 6 is viewed, recording and storage are enabled, and the magnetic field 5 of the magnet 1 is set.
The center of can also be obtained geometrically.

Then, the center of the obtained magnetic field 5 is compared with the center of the actually determined magnetic field by comparing the geometric center of the image captured by the camera 10 with the center of the actually determined magnetic field. It is possible to measure the deviation from the scientific center.

Incidentally, it goes without saying that the design change does not substantially change the working effect even when the body is laid down instead of standing.

Next, in the embodiment shown in FIGS. 4 and 5, the inspection is performed in the lateral direction of the multi-pole magnet 1, and the adjacent pole pieces 3, 3 or 3 ', 3'.
In a plane equidistant from (a plane passing through the central axis of the magnet 1 in FIG. 4 and a vertical plane), the magnetic force acts perpendicularly to the plane, so that the magnetic fluid 8 of the measuring instrument 6 does not change. , In a part slightly separated from these planes, magnetic force attracted in the pole direction is generated in the vicinity of the central axis, so that the magnetic particles move in the pole direction as the center of the position in the plane corresponding to the direction perpendicular to the central axis. , For that purpose, a light-colored (for example, white) line 9 ′ is provided near the center of the measuring device 6.
Appears as shown in FIG.

Therefore, it is possible to determine the approximate characteristics of the magnet 1 in the axial direction by observing (or photographing with a camera) the white line 9 '.

For example, if the white line 9'is not straight, it can be judged that the magnet material has some defects in the axial direction, and an emergency measure can be taken.

Of course, the embodiment of the invention of this application is not limited to the above-mentioned embodiments. For example, the magnet can be applied to not only the high energy beam acceleration storage device but also the semiconductor manufacturing device, medical device, etc. Various aspects such as applicability can be adopted.

Further, in terms of design modification, the multipole magnet can be applied to 6 poles, 8 poles, etc. in addition to 4 poles, and it goes without saying that the container of the measuring instrument is not limited to the short cylindrical shape.

[0035]

As described above, according to the invention of this application, in an electromagnet such as a multi-pole magnet which is basically frequently used in various precision machinery and equipment, the magnetic field formed by each pole piece has its center. It is extremely important to perform the operation of the equipment according to the theory and as designed, whether or not it has as designed, but the geometric center of mechanical equipment is not always the magnetic field of the magnet in actual operation. In many cases, the center of the magnetic field is not limited to the center of the magnetic field. Therefore, according to the invention of this application, the center of the magnetic field can be reliably determined by a simple method. The excellent effect of being able to accurately judge the property of and to make a good response is exhibited.

Since the center of the magnetic field is measured and determined, the action such as the convergence of the charged particles can be performed as designed in actual operation, and an excellent effect that high-performance operation can be expected is exhibited.

Further, by comparing and comparing the actual center of the magnetic field and the geometrical center and measuring the difference between them, there is an effect that it is possible to appropriately change the assembly and check the installation posture and the like. The characteristics of the magnet can be easily measured and inspected over time, and the original performance of the equipment can be brought out according to the initial design state.

In the conventional case where magnets of the same size are mass-produced, it is necessary to measure the magnetic field distributions individually, which requires an extremely large number of man-hours, and the work is complicated. According to the invention, it is possible to preliminarily inspect all the pieces and to grasp the outline thereof. Therefore, by measuring a predetermined number of magnetic fields in a sampling manner, accurate quality,
Further, there is an advantage that the reliability of the quality can be improved and mass production can be performed.

[Brief description of drawings]

FIG. 1 is a schematic front view of an embodiment of the invention of this application.

FIG. 2 is a sectional view of the same.

FIG. 3 is a perspective view of the measuring device.

FIG. 4 is a partial cutaway schematic perspective view of another embodiment.

FIG. 5 is a perspective view of the magnetic fluid of the measuring device.

[Explanation of symbols]

 8 Magnetic fluid 6 Measuring device 3, 3'pole 1 Multipole magnet 5 Magnetic field

Claims (4)

[Claims] 1. A magnet inspection method for measuring a magnetic field state by setting a measuring instrument in which a magnetic fluid is enclosed in a container made of a non-magnetic thin thin transparent material in a magnetic field of a multi-pole magnet. A method for inspecting a magnet, wherein the magnet is set in a magnetic field space in a substantially parallel posture along the end surface of the magnet to determine the center of the magnetic field. 2. The method for inspecting a magnet according to claim 1, wherein the measuring device is photographed by a camera. 3. A magnet inspection method for measuring a magnetic field state by setting a measuring instrument in which a magnetic fluid is enclosed in a container made of a non-magnetic thin thin transparent material in a magnetic field of a multi-pole magnet. It is characterized in that the magnet is set in a magnetic field space in a substantially parallel posture along the end face of the magnet, and the centers are geometrically determined, and the deviation between the two determined centers is measured. How to inspect magnets. 4. A magnet inspection method for measuring a magnetic field state by setting a measuring instrument in which a magnetic fluid is enclosed in a container made of a non-magnetic thin thin transparent material in a magnetic field of a multi-pole magnet. A magnet inspection method characterized in that the magnet is set in a magnetic field space in the vicinity of the central axis of the magnet in a posture parallel to a plane equidistant from adjacent pole pieces of the magnet and the magnet property is measured.