JP2004354186A - Insulated strut - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide insulated struts which can raise the reliability of junctions between insulated struts and electrode members and normally functioning for a long time by resolving discharge from screws. <P>SOLUTION: The insulated strut comprises two annular electrode members 2 made of metal which are arranged face to face and have a plurality of penetration holes formed to penetrate each of upper and lower surfaces, a plurality of columnar insulated struts 1 made of ceramics of which the both ends have recesses 4 and are contacted to a main surface facing the two electrode members 2 so that the recesses 4 become coaxial with the penetration holes, cylindrical screw stop members 3 made of metal inserted in the recesses 4 and brazed, and screws stopping the electrode members 2 and the insulated strut 1 by inserting in the penetration holes and the screw stop members 3. The recess 4 has a horizontal cross section shape of circle column and curved bottom with a dimple and a metallized layer 4a is formed on its whole inner surface. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an insulating column used for applying a voltage to accelerate a charged particle or the like in a vacuum vessel of a neutral particle heating device used for a nuclear fusion experiment device or the like to generate an acceleration beam. is there.
[0002]
[Prior art]
Conventionally, in a neutral particle heating device used for a nuclear fusion experiment device or the like, an insulating column is used as a part for applying a voltage for accelerating charged particles and generating an acceleration beam, that is, a supporting member such as an acceleration electrode. Have been. FIG. 3 is a perspective view showing the basic configuration of this insulating support column. FIG. 2 is an enlarged cross-sectional view of a joint between the insulating pillar and the electrode member in the insulating pillar. 2 and 3, reference numeral 11 denotes an insulating column, 12 denotes an electrode member connected to an accelerating electrode or the like, 17 denotes a screw hole, and 18 denotes a screw such as a bolt, and these mainly constitute an insulating column.
[0003]
In the insulating column shown in FIG. 2, the insulating column 11 is made of a ceramic such as an aluminum oxide (Al ₂ O ₃ ) sintered body, and one or a plurality of screw holes 17 are formed on each end surface thereof. The electrode member 12 and the screw 18 are made of metal such as SUS.
[0004]
For joining the insulating pillar 11 and the electrode member 12, a through hole is previously formed in the electrode member 12 at a position corresponding to the screw hole 17 of the insulating pillar 11, and the electrode member 12 is applied to both end surfaces of the insulating pillar 11. The screw 18 is inserted through the through hole of the electrode member 12 and screwed into the screw hole 17 of the insulating column 11 to be mechanically joined. (For example, see Patent Document 1 below).
[0005]
In the screw hole 17, a heli-sert having a cylindrical shape made of metal such as stainless steel (SUS) and having inner and outer surfaces thereof threaded may be inserted. In this case, the outer surface of the heli-sert may be inserted. Is screwed into the screw hole 17 of the insulating pillar 11 and the screw 18 is screwed into the threaded portion on the inner surface, so that the screw 18 can be tightened more firmly on the insulating pillar 11.
[0006]
[Patent Document 1]
JP-A-2002-343292 (page 8, FIG. 7)
[0007]
[Problems to be solved by the invention]
However, in the above-mentioned conventional insulating column, since the screw hole 17 is directly screwed into the insulating pillar 11 made of ceramic as shown in FIG. 2, a screw is screwed into the screw hole 17 of the insulating pillar 11 and tightened. As a result, when the electrode member 12 is mechanically joined, a stress such as a tensile stress or a shear stress is applied to the threaded portion of the screw hole 17 via the screw 18, and the threaded portion of the screw hole 17 is damaged such as a chip or a crack. Was easy to occur.
[0008]
If such a threaded portion of the screw hole 17 is damaged, the strength of the screw 18 to the insulating column 11 is reduced, and the insulating column 11 and the electrode member 12 cannot be firmly joined to each other. There was a problem that it disappeared.
[0009]
Particularly in recent years, the neutral particle heating device in the nuclear fusion experiment device has become larger, and accordingly, the stress such as tensile stress and shear stress applied to the threaded portion of the screw hole 17 via the screw 18 has increased, Breakage of the threaded portion of the insulating pillar 11 has come to be noticeable.
[0010]
When the electrode member 12 is connected to an accelerating electrode or the like and a high voltage is applied, a high voltage is also applied to the screws 18 screwed into both end surfaces of the insulating column 11, and the high voltage is applied from the corners of the screws 18 to the opposite screws 18. There is also a problem that discharge easily occurs.
[0011]
Therefore, the present invention has been completed in view of the above problems, and an object of the present invention is to prevent the insulating pillar from being damaged even if the electrode member is firmly screwed to the insulating pillar, and to allow the insulating pillar and the electrode member to be in contact with each other. An object of the present invention is to provide an insulating support column that can improve the reliability of bonding, eliminate discharge from a screw, and function normally for a long time.
[0012]
[Means for Solving the Problems]
The insulating support pillar of the present invention has two annular electrode members made of metal, in which a plurality of through-holes are formed facing each other and penetrate the upper and lower surfaces, and concave portions are formed on both end surfaces, A plurality of cylindrical insulating pillars made of ceramics, each of which has both ends joined to the opposite main surfaces of the two electrode members such that the recess is coaxial with the through-hole; A brazed cylindrical screw member made of metal, and a screw inserted into the through hole and screwed into the screw member to screw the electrode member and the insulating pillar. Wherein the concave portion has a circular cross section and a curved surface with a concave bottom surface, and a metallized layer is formed on the entire inner surface.
[0013]
According to the present invention, two annular electrode members made of metal, each of which has a plurality of through-holes penetrating through the upper and lower surfaces and being opposed to each other, are formed with concave portions on both end surfaces. A plurality of ceramic insulating pillars made of ceramics, both end faces of which are joined to opposing main surfaces of the two electrode members so as to be coaxial with the through hole, and a metal fitted into the recess and brazed. A cylindrical screwing member, and a screw inserted into the through hole and screwed into the screwing member, thereby screwing the electrode member and the insulating pillar. Screw processing that has a circular shape and a concave surface with a concave bottom surface, and a metallized layer is formed on the entire inner surface, so that ceramic insulating pillars are susceptible to breakage such as chipping Since it can be screwed without applying it, it is possible to effectively suppress the occurrence of breakage such as cracks and cracks in the insulating pillar when screwing when joining the insulating pillar to the opposite main surface of the electrode member. it can.
[0014]
Further, since the brazing material for joining the screw member and the insulating pillar can effectively reduce the stress caused by screwing, the effect of preventing damage to the insulating pillar can be further improved. As a result, it is possible to effectively suppress the occurrence of breakage such as chips and cracks in the insulating pillar even in a large insulating pillar used in a neutral particle heating device in a recent fusion experiment apparatus.
[0015]
Furthermore, the concave portions formed on both end surfaces of the insulating pillar have a circular cross-sectional shape and a curved surface with a concave bottom surface, and a metallized layer is formed on the entire inner surface thereof, so that the electrode member is not formed. When a high voltage is applied by connecting to an accelerating electrode or the like, the charge generated in the screw can be dispersed over the entire smooth curved metallization layer on the inner surface of the concave portion without concentrating on the corners, and the electric charge between the opposing screws can be reduced. Discharge can be effectively suppressed.
[0016]
Further, in the insulating pillar according to the present invention, preferably, the thickness of the screwing member is 0.5 to 2.5 mm.
[0017]
The insulating pillar of the present invention has a thickness of 0.5 to 2.5 mm for the screwing member, so that the stress due to the difference in thermal expansion generated when the screwing member is brazed to the insulating pillar can cause the insulating pillar to have cracks, It is possible to prevent the occurrence of damage such as cracks, and to prevent the screwing member from being deformed and unable to be screwed. As a result, it is possible to provide an insulating pillar that functions more normally over a long period of time.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
The insulating support of the present invention will be described in detail below. FIG. 1 is a sectional view of a joint between an insulating pillar and an electrode member in an insulating pillar according to the present invention. In FIG. 1, reference numeral 1 denotes an insulating pillar, 2 denotes an electrode member, 3 denotes a screw member, 4 denotes a concave portion, and 5 denotes a brazing material.
[0019]
The insulating support pillar of the present invention has two annular electrode members 2 made of metal, each of which has a plurality of through-holes penetrating through the upper and lower surfaces, and has concave portions 4 formed at both end surfaces. A plurality of cylindrical insulating pillars 1 made of ceramics, both ends of which are joined to opposing main surfaces of the two electrode members 2 such that the recess 4 is coaxial with the through hole; The electrode member 2 and the insulating column 1 are screwed by being inserted into the through hole and screwed into the screw member 3 by screwing the cylindrical screw member 3 made of metal fitted into the recess 4 and brazed. The concave portion 4 has a circular cross section and a curved surface with a concave bottom surface, and a metallized layer 4a is formed on the entire inner surface.
[0020]
The insulating pillar 1 of the present invention has a circular cross section or a polygonal shape such as a square or a hexagon, and is made of a ceramic such as an Al ₂ O ₃ sintered body. On both end surfaces of the insulating column 1, a concave surface 4 having a concave bottom surface, for example, a spherical or parabolic curved surface is formed, and molybdenum (Mo), manganese (Mn), tungsten (W) ) Etc. are formed.
[0021]
The metallized layer 4a functions as a base metal layer when the screwing member 3 is brazed, and when the electrode member 2 is connected to an accelerating electrode or the like and a high voltage is applied, the charge generated in the screw 8 is applied to the corners. It also acts to disperse without concentrating. Such a metallized layer 4a is preferably formed by applying a metal such as nickel (Ni) or gold (Au) having excellent wettability with the brazing material 5 to a thickness of about 1 to 10 μm by plating on the surface thereof. The screw member 3 can be firmly brazed to the metallized layer 4a. Further, the opening of the recess 4 may be chamfered, so that the meniscus of the brazing material 5 for joining the screwing member 3 and the recess 4 is good, and the screwing member 3 is attached to the recess 4. Can be brazed firmly.
[0022]
The concave portion 4 formed on both end surfaces of the insulating column 1 has a circular cross-sectional shape and a curved surface with a concave bottom surface. Since the metallized layer 4a is formed on the entire inner surface, the electrode member is formed. When a high voltage is applied by connecting 2 to an accelerating electrode or the like, the charge generated in the screw 8 can be dispersed over the entire smooth curved metallized layer 4a on the inner surface of the recess 4 without concentrating on the corners. The discharge between the screws 8 can be effectively suppressed.
[0023]
The electrode member 2 is an annular metal member in which a plurality of through-holes having a circular cross section penetrating the upper and lower surfaces at the annular portion are formed at equal intervals, and is made of SUS or the like. The electrode member 2 is joined to the insulating pillar 1 by inserting a screw 8 made of SUS or the like into the through hole and screwing the screw 8 into the screw fixing member 3.
[0024]
Preferably, the surface of the electrode member 2 has small irregularities. Specifically, the arithmetic average roughness (Ra) of the surface is preferably Ra ≦ 0.4 μm. In this case, when a voltage is applied to the electrode member 2 to accelerate charged particles such as electrons, generation of minute discharge between the electrode members 2 can be effectively suppressed, and a high voltage can be stably applied. The number of through holes formed in the electrode member 2 is about 4 to 6.
[0025]
The screwing member 3 is formed of a cylindrical metal member having an inner peripheral surface subjected to screw processing, and is fitted into the concave portion 4 of the insulating pillar 1 and is made of a brazing material such as silver (Ag) brazing or Ag-copper (Cu) brazing. It is brazed by the material 5. For example, the screw member 3 is preferably made of a material having a coefficient of thermal expansion close to that of the ceramics of the insulating column 1 such as an Fe—Ni—Co alloy. The occurrence of a difference in expansion is suppressed, and the occurrence of damage such as cracks in the insulating column 1 and the deformation of the screw member 3 are prevented.
[0026]
Further, the brazing material 5 for joining the screwing member 3 and the metallized layer 4a on the inner surface of the concave portion 4 is preferably applied to the entire surface of the metallized layer 4a. Thereby, the adhesion between the brazing material 5 and the metallized layer 4a can be further improved, and the occurrence of discharge in the brazing material 5 protruding between the lower end surface of the screwing member 3 and the metallized layer 4a can be further reduced. It can be suppressed effectively.
[0027]
Further, since the screwing member 3 is cylindrical, the screwing member 3 is brazed to the metallized layer 4a of the concave portion 4 with the brazing material 5 and then the brazing material 5 in the metalized layer 4a below the screwing member 3 is formed. The state of the flow can be confirmed, and it can be visually confirmed whether or not brazing has been completed over the entire joint surface between the screwing member 3 and the concave portion 4.
[0028]
Preferably, the thickness of the screw member 3 is 0.5 to 2.5 mm. With this configuration, the screw member 3 is insulated by a stress caused by a difference in thermal expansion generated when the screw member 3 is brazed to the insulating column 1. It is possible to prevent the column 1 from being damaged such as chips and cracks, and to prevent the screw member 3 from being deformed and the screw 8 from being unable to be screwed. When the thickness is smaller than 0.5 mm, the screw 8 is hardly screwed by being deformed due to a difference in thermal expansion when the screwing member 3 is brazed to the insulating pillar 1. On the other hand, if the thickness exceeds 2.5 mm, a large stress due to a difference in thermal expansion occurs between the screwing member 3 and the insulating pillar 1 during brazing, and the stress causes breakage such as cracks in the insulating pillar 1. Easier to do.
[0029]
Note that the thickness of the screw member 3 refers to the distance between the top of a screw thread formed on the inner peripheral surface of the screw member 3 and the outer side surface of the screw member 3.
[0030]
In addition, it is more preferable that the screw processing formed on the inner peripheral surface of the screwing member 3 does not reach the lower end. Accordingly, there is no sharp point around the lower end of the screwing member 3 where charges are easily concentrated, and it is possible to more effectively suppress the occurrence of discharge in the screwing member 3.
[0031]
The screw 8 has a flat bottom and is screwed into the screw member 3 and screwed so that the screw bottom of the screw 8 and the lower end of the screw member 3 are flush. Is good. As a result, it is possible to more effectively suppress the electric charge from being concentrated on the screw bottom of the screw 8 and the lower end of the screw member 3, and to more effectively suppress the occurrence of electric discharge in the screw 8 and the screw member 3. be able to.
[0032]
【Example】
An embodiment of the present invention will be described below.
[0033]
The structure shown in FIG. 1 was produced as follows.
[0034]
A cylindrical insulating pillar 1 having a diameter of 80 mm and a length of 290 mm made of an Al ₂ O ₃ sintered body having a purity of 99% by weight was prepared. Two concave portions 4 each having a diameter of 15 mm and a depth of 26 mm were provided on both end surfaces of the insulating column 1. The bottom corner of the concave portion 4 was an arc-shaped curved surface having a radius of 5 mm, and the opening was chamfered by 3 mm.
[0035]
Then, a metal paste containing Mo, Mn, and silica (SiO ₂ ) in a proportion of 89% by weight, 6% by weight, and 5% by weight, respectively, on the entire surfaces of both end surfaces of the insulating column 1, the inner surface of the concave portion 4, and the entire surface of the chamfered portion. Was printed and coated to a thickness of 10 μm, dried, and fired at 1400 ° C. in a humidified forming gas. In this manner, the metallized layer 4a made of the Mo-Mn alloy was applied to the entire surfaces of both ends of the insulating column 1, the inner surface of the concave portion 4, and the entire chamfered portion. Thereafter, a Ni plating layer was applied to a thickness of about 2 μm on the metallized layer 4a by an electrolytic plating method.
[0036]
Next, M10 (according to JIS B0123) threading is applied to the concave portion 4 of the insulating pillar 1 over the entire length of the inner diameter of 15 mm (the thickness of the screwing member 3 becomes 2.5 mm). A screwing member 3 made of a Fe—Ni—Co alloy having a cylindrical shape with a length of 21 mm and an outer surface Ra of 6.3 μm is fitted, and the outer surface of the screwing member 3 is brazed to the metallized layer 4 a with a brazing material 5. I fixed it. At this time, a brazing material 5 made of a wire-shaped Ag-Cu alloy having a diameter of 1 mm is provided between the chamfered portion of the concave portion 4 of the insulating pillar 1 and the screwing member 3 in a ring shape having a diameter of 15 mm, and is placed. It was heated to 820 ° C. and joined. Thus, the manufactured product was designated as Sample A1.
[0037]
Further, a sample A2 with the threaded portion M11 inside the screwing member 3 (thickness of the screwing member 3 is 2 mm) and a sample A3 with a threaded portion M12 (the thickness of the screwing member 3 is 1.5 mm) A sample A4 (thickness of the screw member 3 was 1 mm) having a threaded portion of M13 and a sample A5 (thickness of 0.5 mm of the screw member 3) having a threaded portion of M14 were produced.
[0038]
As a comparative example, a thread of M9 (according to JIS B0123) having an outside diameter of 15 mm and the entire inside length is applied to the concave portion 4 of the same insulating pillar 1 as the sample A1 (the thickness of the screw member 3 is 3 mm). A screw member 3 made of a Fe-Ni-Co alloy having a cylindrical shape with a length of 21 mm and an outer surface Ra of 6.3 μm is fitted, and the outer surface of the screw member 3 is brazed to the metallized layer 4a. 5 and fixed by brazing. The joining method was the same as that of Sample A1. The sample manufactured in this manner was designated as Sample B.
[0039]
Further, as a comparative example, M4 (according to JIS B0123) screw processing is applied to the concave portion 4 of the same insulating pillar 1 as the sample A1 with an outer diameter of 14.8 mm and the entire inner length (in this way, the screw fixing member 3 is formed). The screwing member 3 made of a Fe—Ni—Co alloy having a cylindrical shape with a length of 21 mm and an outer surface Ra of 6.3 μm was fitted into the metallizing layer 4a. The outside surface of 3 was brazed and fixed with a brazing material 5. The joining method was the same as that of Sample A1. The sample manufactured in this manner was designated as Sample C.
[0040]
For each of the samples A1 to A5, B, and C, a bolt 8 adapted to the threaded portion of the screwing member 3 was inserted, and a test was performed by applying a torque of 65 Nm.
[0041]
Samples A1 to A5 did not break even at 65 N · m torque.
[0042]
Sample B had a crack starting from the concave portion 4 of the insulating pillar 1 during brazing.
[0043]
In the sample C, the screw member 3 was too thin and the screw member 3 was deformed at the time of brazing with the metallization layer 4a, so that the bolt 8 could not be inserted.
[0044]
As a result, it was found that the thickness of the screwing member 3 is preferably 0.5 to 2.5 mm.
[0045]
It should be noted that the present invention is not limited to the examples and examples of the above-described embodiment, and changes and improvements can be made without departing from the scope of the present invention.
[0046]
【The invention's effect】
According to the present invention, two annular electrode members made of metal, each of which has a plurality of through-holes penetrating through the upper and lower surfaces and being opposed to each other, are formed with concave portions on both end surfaces. A plurality of ceramic insulating pillars made of ceramics, both end faces of which are joined to opposing main surfaces of the two electrode members so as to be coaxial with the through hole, and a metal fitted into the recess and brazed. A cylindrical screwing member, and a screw inserted into the through hole and screwed into the screwing member, thereby screwing the electrode member and the insulating pillar. Screw processing that has a circular surface shape and a concave surface with a concave bottom surface, and a metallized layer is formed on the entire inner surface, which is likely to cause breakage such as chipping of ceramic insulating pillars Since it can be screwed without applying it, it is possible to effectively suppress the occurrence of breakage such as cracks and cracks in the insulating pillar when screwing when joining the insulating pillar to the opposite main surface of the electrode member. it can.
[0047]
Further, since the brazing material for joining the screw member and the insulating pillar can effectively reduce the stress caused by screwing, the effect of preventing damage to the insulating pillar can be further improved. As a result, it is possible to effectively suppress the occurrence of breakage such as chips and cracks in the insulating pillar even in a large insulating pillar used in a neutral particle heating device in a recent fusion experiment apparatus.
[0048]
Furthermore, the concave portions formed on both end surfaces of the insulating pillar have a circular cross-sectional shape and a curved surface with a concave bottom surface, and a metallized layer is formed on the entire inner surface thereof, so that the electrode member is not formed. When a high voltage is applied by connecting to an accelerating electrode or the like, the charge generated in the screw can be dispersed over the entire smooth curved metallization layer on the inner surface of the concave portion without concentrating on the corners, and the electric charge between the opposing screws can be reduced. Discharge can be effectively suppressed.
[0049]
The insulating pillar of the present invention has a thickness of 0.5 to 2.5 mm for the screwing member, so that the stress due to the difference in thermal expansion generated when the screwing member is brazed to the insulating pillar can cause the insulating pillar to have cracks, It is possible to prevent the occurrence of damage such as cracks, and to prevent the screwing member from being deformed and unable to be screwed. As a result, it is possible to provide an insulating pillar that functions more normally over a long period of time.
[Brief description of the drawings]
FIG. 1 is a partially enlarged sectional view showing an example of an embodiment of a joint between an insulating pillar and an electrode member in an insulating pillar of the present invention.
FIG. 2 is a partially enlarged cross-sectional view showing a joint between an insulating pillar and an electrode member in a conventional insulating pillar.
FIG. 3 is a perspective view of a conventional insulating pillar.
[Explanation of symbols]
1: insulating column 2: electrode member 3: screw member 4: concave portion 4a: metallized layer 5: brazing material 8: screw

Claims (2)

Two annular electrode members made of metal, each of which has a plurality of through holes formed so as to face each other and penetrate the upper and lower surfaces, and concave portions are formed on both end surfaces, and the concave portions are formed with the through holes. A plurality of cylindrical insulating pillars made of ceramics, both end faces of which are joined to opposing main faces of the two electrode members so as to be coaxial, and a metal fitted into the recess and brazed. A cylindrical screwing member, and a screw that is inserted into the through hole and screwed into the screwing member, thereby screwing the electrode member and the insulating column. The insulating pillar according to claim 1, wherein the concave portion has a circular cross section and a curved surface with a concave bottom surface, and a metallized layer is formed on the entire inner surface. 2. The insulating pillar according to claim 1, wherein the thickness of the screw member is 0.5 to 2.5 mm.

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