JP2008084709A - Airtight terminal and electric device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an airtight terminal capable of holding airtightness without hindering the connection to external equipment, or the like, due to the solder material creeping up on the center conductor. <P>SOLUTION: This airtight terminal is constituted of a columnar center conductor 2, having a first part 2a and a second part 2b having a thinner thickness than that of the first part 2a; a cylindrical ceramic insulator 1 which has a through-hole 1a, into which the center conductor 2 is inserted and penetrated at the center part thereof and in which a metallized layer 4 is formed around an opening of the through-hole 1a; and a fixing bracket 3 in which the inner cylinder 3b is arranged inside the outer cylinder 3a, in which one end of the outer cylinder 3a and the inner cylinder 3b is closed between the outer cylinder 3a and the inner cylinder 3b, and which has an annular part 3d projecting toward the inside of the inner cylinder 3b at the other end of the inner cylinder 3b; the other end of the outer cylinder 3a and the metallized layer 4 are brazed, and a stepped part 2c between the first part 2a and the second part 2b of the center conductor 2 is brazed to the annular part 3d; and the solder material can be prevented from creeping up on a screw part 2a, and brazing reliability can be enhanced. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an airtight terminal for conducting an electric signal inside and outside an airtight container, and more particularly to an airtight terminal having an improved brazing structure between a central conductor and a fixing bracket.

  2. Description of the Related Art Conventionally, an airtight terminal is a fixing bracket in which, for example, a ceramic insulator having a cylindrical through hole and a central conductor inserted through the through hole are made of a metal such as iron (Fe) -nickel (Ni) -cobalt (Co) alloy. (See, for example, Patent Document 1 and Patent Document 2). An example of such an airtight terminal is shown in FIGS.

  FIG. 3 is a cross-sectional view showing an example of a conventional hermetic terminal. The conventional hermetic terminal has a center conductor 22, a cylindrical ceramic insulator 21 having a through hole 21a through which the center conductor 22 is inserted, and an annular portion 23b in which one end of the cylinder 23a protrudes toward the inside of the cylinder. It consists of a fixture 23. The inner peripheral side of the annular portion 23b in the fixing bracket 23 is a diaphragm that is bent obliquely toward the inside of the cylinder. Then, by brazing between the inner peripheral surface of the cylinder 23a of the fixing bracket 23, the outer peripheral surface 21b of the ceramic insulator 21, the inner peripheral side of the annular portion 23b of the fixing bracket 23, and the outer peripheral surface 22b of the center conductor 22, A central conductor 22 is fixed to the ceramic insulator 21.

FIG. 4 is a cross-sectional view showing another example of a conventional hermetic terminal. The hermetic terminal shown in FIG. 4 includes a center conductor 22, a cylindrical ceramic insulator 21 having a through hole 21 a through which the center conductor 22 is inserted, and a fixing bracket 23 that fixes the center conductor 22 to the ceramic insulator 21. Become. The ceramic insulator 21 has a metallized layer 24 such as molybdenum (Mo) -manganese (Mn) formed on one end surface. The central conductor 22 is made of copper (Cu), iron (Fe), Fe—Ni—Co alloy, Fe—Ni alloy, or the like. The fixture 23 is made of an Fe-Ni-Co alloy or the like, and has an annular portion 23b that protrudes toward the inside of the cylinder at one end of the cylinder 23a, and protrudes toward the outside of the cylinder 23a at the other end of the cylinder 23a. Has an annular flange 23c. The metallized layer 24 of the ceramic insulator 21 and the flange 23c of the fixing bracket 23, and the outer peripheral surface 22b of the center conductor 22 and the inner peripheral side of the annular portion 23b of the fixing bracket 23 are each made of silver (Ag) solder or the like. The brazing material 25 is brazed and joined. With this configuration, the ceramic insulator 21 and the center conductor 22 can be hermetically brazed and joined without causing a large stress due to a difference in thermal expansion between the ceramic insulator 21 and the center conductor 22.
Japanese Patent No. 2903976 JP 2006-210172 A

  However, in the above-described conventional hermetic terminal shown in FIGS. 3 and 4, after brazing the fixing bracket 23 and the central conductor 22, the brazing material 25 crawls up to the outer peripheral surface 22 b of the central conductor 22, and the central conductor 22 is screwed. When the portion 22a and the like are provided, the screw groove is filled with the brazing material 25, and thus, there is a problem that the screw cannot be tightened to the root when the external connection line or the like is fixed to the airtight terminal by screwing.

  Accordingly, the present invention has been completed in view of the above problems, and its purpose is to achieve a hermeticity that can maintain airtightness without causing a brazing material to crawl up on the central conductor and without hindering connection with external devices. To provide a terminal.

  The hermetic terminal of the present invention has a columnar center conductor having a first portion and a second portion whose thickness is smaller than that of the first portion, and a through hole through which the center conductor is inserted into the inside and outside. A cylindrical ceramic insulator in which a metallized layer is formed around the opening of the through-hole, and an inner cylinder disposed inside the outer cylinder, and one end of the outer cylinder and the inner cylinder is the outer cylinder And a fixing bracket having an annular portion protruding toward the inside of the inner cylinder at the other end of the inner cylinder, and viewed from above the axial extension line of the through hole. Then, the other end of the outer cylinder and the metallized layer are brazed so that the inner side opening of the annular portion is located within the opening range of the through hole, and the central conductor is connected to the inner cylinder and the through hole. And the step between the first part and the second part is inserted Characterized in that it is brazed to Jo unit.

  In the hermetic terminal of the present invention, preferably, a cylindrical protrusion is provided at the opening of the through hole so as to be continuous with the through hole, and an inner peripheral surface of the outer cylinder is the protrusion. It is joined to the outer peripheral surface of this and the end surface of the said ceramic insulator.

  The hermetic terminal of the present invention is preferably characterized in that the central conductor is made of stainless steel.

  In addition, an electrical device of the present invention includes an airtight container and the airtight terminal according to any one of claims 1 to 3 attached to an outer wall of the airtight container.

  The hermetic terminal of the present invention has a columnar center conductor having a first portion and a second portion whose thickness is smaller than that of the first portion, and a through hole through which the center conductor is inserted into the inside and outside at the center portion. A cylindrical ceramic insulator in which a metallized layer is formed around the opening of the through hole, an inner cylinder is disposed inside the outer cylinder, and one end of the outer cylinder and the inner cylinder is between the outer cylinder and the inner cylinder. And the other end of the inner cylinder has a fixing bracket having an annular part protruding toward the inner side of the inner cylinder, and the inner opening of the annular part is the through hole when viewed from the axial extension line of the through hole. The other end of the outer cylinder and the metallized layer are brazed so as to be located within the opening range of the center, the center conductor is inserted through the inner cylinder and the through hole, and between the first part and the second part. Since the stepped part is brazed to the annular part, the molten brazing material is connected between the inner cylinder of the fixing bracket and the central conductor. Flows into and brazed by flowing through the gap between the annular portion and the stepped portion by the capillary phenomenon. Excess brazing material collects between the inner cylinder and the central conductor, and the brazing material does not crawl up on the upper side of the fixing bracket, so that an external connection line or the like can be reliably attached to the central conductor.

  In the hermetic terminal of the present invention, preferably, the opening of the through hole is provided with a cylindrical protrusion so as to be continuous with the through hole, and the inner peripheral surface of the outer cylinder is the outer peripheral surface of the protrusion and Since it is joined to the end face of the ceramic insulator, the fixing bracket is joined to both the outer peripheral surface and the end face of the protruding portion of the ceramic insulator, so that the center conductor and the ceramic insulator can be joined with a strong joint strength.

  In addition, the hermetic terminal of the present invention is preferably made of stainless steel as the center conductor, so that it has oxidation resistance and corrosion resistance to the temperature and atmosphere inside the apparatus to which the hermetic terminal is attached, and the threaded portion is polished. Excellent wear.

  In addition, since the electrical device of the present invention includes the hermetic container and the hermetic terminal of the present invention attached to the outer wall of the hermetic container, the reliability of the external connection line and the like can be reliably connected. Can with high airtight device.

  The airtight terminal of the present invention will be described in detail below. FIG. 1 is a cross-sectional view showing an example of an embodiment of an airtight terminal of the present invention, and FIG. 2 is an enlarged cross-sectional view of a main part showing an enlarged brazed portion in the airtight terminal of FIG. The hermetic terminal of the present invention is formed substantially line-symmetric with respect to the central axis. That is, for example, the cross-sectional view of the cross section indicated by the vertical center line of the cross-sectional view of FIG. 1 has the same cross-sectional shape as FIG.

  In these drawings, reference numeral 1 denotes a ceramic insulator having a through hole 1a in the center, 1b denotes a cylindrical protrusion provided on the end surface 1c of the ceramic insulator 1 so as to be continuous with the through hole 1a, and 1c denotes a ceramic insulator. 1 is an end surface, 2 is a columnar center conductor, 2a is a first portion of the center conductor 2, 2b is a second portion of the center conductor 2 having a thickness W2 smaller than the thickness W1 of the first portion 2a, 2a 'is a screw part provided in the first part 2a of the central conductor 2, 2c is a step part formed between the first part 2a and the second part 2b, 3 is a fixture, and 3a is fixed An outer cylinder of the metal fitting 3, an inner cylinder 3 b of the fixing metal fitting 3, a closed portion of the fixing metal fitting 3 c closed between the outer cylinder 3 a and the inner cylinder 3 b at one end of the outer cylinder 3 a and the inner cylinder 3 b, 3d is provided in an annular shape so as to protrude toward the inside of the inner cylinder 3b at the other end of the inner cylinder 3b. Annular portions, 4 is a metallized layer formed around the opening of the through hole 1a. 5 is a brazing material, 5a is a brazing material for joining the metallized layer 4 of the ceramic insulator 1 and the fixing metal 3, and 5b is a brazing material for joining the fixing metal 3 and the central conductor 2.

  As shown in FIGS. 1 and 2, the hermetic terminal of the present invention has a first part (head) 2a and a second part (trunk) that is thinner than the thickness W1 of the first part 2a. A center conductor 2 having a cylindrical shape or a polygonal column shape having 2b and a through hole 1a having a cylindrical shape or a polygonal column shape through which the center conductor 2 is inserted in and out at the center, and an end surface 1c around the opening of the through hole 1a Alternatively, the cylindrical ceramic insulator 1 having the metallized layer 4 formed on the outer peripheral surface of the protruding portion 1b, and the inner cylinder 3b is disposed inside the outer cylinder 3a, and one end of the outer cylinder 3a and the inner cylinder 3b ( A center conductor having an annular portion 3d whose upper end is closed by a closing portion 3c between the outer tube 3a and the inner tube 3b and which projects toward the inside of the inner tube 3b at the other end (lower end) of the inner tube 3b. 2 and a fixing metal 3 for joining the metallized layer 4 of the ceramic insulator 1 to each other.The fixing fitting 3 is arranged so that the inner opening through which the central conductor 2 of the annular portion 3d is inserted is located within the opening range of the through hole 1a when viewed from the axial extension line on the upper side of the through hole 1a. The other end (lower end) of the outer cylinder 2a and the metallized layer 4 are brazed with a brazing material 5a, and the central conductor 2 is inserted through the inner cylinder 2b and the through hole 1a of the fixing bracket 3 and the stepped portion 2c and the annular portion. 3d is brazed with a brazing material 5b.

  Moreover, in the airtight terminal of this invention, as shown in FIG.1, FIG.2, the cylindrical protrusion part 1b is provided so that it may continue with the through-hole 1a, and the inner peripheral surface of the outer cylinder 3a of the fixing metal 3 is provided. It is preferable to be joined to the metallized layer 4 formed over the outer peripheral surface of the protruding portion 1b and the end surface 1c of the ceramic insulator 1. However, the protrusion 1b is not provided, and is bonded to the metallized layer 4 formed on the end surface 1c of the ceramic insulator 1 by, for example, an annular flange provided so as to protrude outward at the lower end of the outer cylinder 3a. It may be.

  When the protruding portion 1b is provided and the outer cylinder 3a of the fixing bracket 3 is joined to the protruding portion 1b and the end face 1c, the bonding area between the fixing bracket 3 and the ceramic insulator 1 is increased, and the bonding strength is increased. In addition, the external force applied to the center conductor 2 is transmitted to the fixing metal 3, and the shearing force applied to the ceramic insulator 1 from the fixing metal 3 to the ceramic insulator 1 is applied to the end surface 1c of the ceramic insulator 1. The ceramic insulator 1 can be made difficult to crack because it is dispersed in two directions, the surface direction and the vertical direction perpendicular thereto.

  In the hermetic terminal of the present invention, it is preferable that the center conductor 2 is made of stainless steel.

  As an example of the hermetic terminal having the above configuration, in FIGS. 1 and 2, a side metallized layer 6 is formed on the outer peripheral surface of the ceramic insulator 1 as an attachment part for attaching the hermetic terminal to an electric device, and Fe—Ni A structure in which a sleeve 7 made of a Co alloy or the like is brazed is shown. And a through-hole is made in the wall part which comprises the airtight container part of electrical apparatuses, such as a semiconductor manufacturing apparatus, an electronic device, and a semiconductor device, The metal member and airtight terminal around the inner peripheral surface of this through-hole, or opening of a through-hole By joining the sleeve 7 by welding, brazing or the like, the electrical device can be sealed and an electrical signal can be conducted to the inside and outside of the hermetic container by the center conductor 2.

  Hereinafter, the airtight terminal of the present invention will be described with reference to FIGS.

The ceramic insulator 1 is an insulating material made of alumina (Al ₂ O ₃ ) ceramics or the like, for example, and has a function of holding the central conductor 2 while maintaining electric insulation with an electric device. When the ceramic insulator 1 is made of, for example, Al ₂ O ₃ ceramics, a binder such as polyvinyl alcohol is added to and mixed with raw material powders such as alumina, silicon oxide (SiO ₂ ), magnesium oxide (MgO), and calcium oxide (CaO). At the same time, this is filled into a press mold having a predetermined shape and pressed at a predetermined pressure to obtain a press-molded body provided with the through hole 1a. Thereafter, the press-molded body is fired at a temperature of about 1600 ° C.

  It is desirable to provide a thin portion at the lower portion of the outer peripheral surface of the ceramic insulator 1 and to provide the metallized layer 6 in this thin portion. The position of the sleeve 6 can be reliably fixed by the step formed between the thin portion.

  The metallized layer 4 and the metallized layer 6 are made of a metal paste mainly composed of a metal powder such as tungsten (W), molybdenum (Mo), manganese (Mn), or the like, and the end surface 1c of the ceramic insulator 1, the end surface of the stepped portion, It is formed by applying to a predetermined site such as the outer periphery and baking at a temperature of about 1300 ° C. in a hydrogen atmosphere. In order to improve the wettability with the brazing material 5, the surface of the metallized layers 4 and 6 is preferably plated with Ni with a thickness of about 3 μm.

  The center conductor 2 is a component that functions as a terminal through which the second portion 2b is inserted into the through hole 1a of the ceramic insulator 1 and electrically connects the inside and outside of the electric device. A threaded portion 2a is formed on the outer peripheral surface of the part 1a for connection with an external device. A step portion 2c is formed between the first portion 2a and the second portion 2b because the thicknesses W1 and W2 are different. The step portion 2c is brought into contact with the upper surface of the annular portion 3d of the fixing metal 3 and has a function of positioning the center conductor 2 and a function of being brazed by the brazing material 5b. By providing the stepped portion 2c on the central conductor 2, the bonding area with the fixing bracket 3 is increased, so that the bonding strength is increased.

  The center conductor 2 is made of Cu, Fe—Ni—Co alloy, stainless steel, or the like, but from the viewpoint of oxidation resistance and corrosion resistance to the temperature and atmosphere inside the electric device, and further from the viewpoint of wear resistance of the screw portion 2a ′. It is desirable to use stainless steel.

  The fixing bracket 3 includes an outer cylinder 3a to be brazed to the ceramic insulator 1, an inner cylinder 3b through which the central conductor 2 is inserted, an outer cylinder 3a therebetween, a blocking portion 3c connecting one end of the inner cylinder 3b, and an inner cylinder The other end of the portion 3c is composed of an annular portion 3d protruding toward the inner peripheral side, and an Fe—Ni—Co alloy is formed into a predetermined shape by drawing or the like. The outer cylinder 3a in plan view is similar to the outer peripheral surface of the projecting portion 1b, and the through opening provided in the center of the inner cylinder 3b and the annular portion 3d is similar to the cross section of the central conductor 2.

  And the clearance gap formed between the inner peripheral surface of the inner cylinder 3b and the 1st site | part 2a outer peripheral surface of the center conductor 2 is between the annular part 3d and the 2nd site | part 2b outer peripheral surface of the center conductor 2. FIG. It should be larger than the gap that is formed. Then, when the preform that becomes the brazing material 5b is disposed between the first portion 2a and the inner cylinder 3b and heated, the brazing material 5 melts and flows between the first portion 2a and the inner cylinder 3b, Furthermore, it spreads wet between the annular portion 3d and the stepped portion 2c and between the annular portion 3d and the outer peripheral surface of the second portion 2b. By narrowing the gap between the outer peripheral surface of the second portion 2b and the annular portion 3d, the brazing material is interposed between the annular portion 3d and the outer peripheral surface of the second portion 2b by the surface tension of the brazing material 5. 5 does not flow down, and excess brazing material 5 accumulates in a large gap between the inner cylinder 3b and the first portion 2a.

  In addition, because the fixing bracket 3 is composed of an outer cylinder 3a, a closing part 3c, an inner cylinder 3b, and an annular part 3d, and the respective parts are joined via corners, it has a curved shape as a whole. Even if a strong impact is applied to the center conductor 2, the impact force can be absorbed by the corners between the portions of the fixture 3, and the ceramic insulator 1 is not easily destroyed.

  The sleeve 6 is formed of a Fe—Ni—Co alloy or the like into a cylindrical shape by grinding or extrusion molding. The surfaces of the fixing metal 3 and the sleeve 6 are preferably subjected to Ni plating of about 2 μm in order to improve the wettability with the brazing material 5.

  Thereafter, the ceramic insulator 1 and the center conductor 2 are connected to each other by a brazing material 5b such as Ag-Cu brazing through the fixing fitting 3, and the ceramic insulator 1 and the sleeve 6 are brazed to a brazing material 5a such as Ag-Cu brazing. By brazing at about 800 ° C., the hermetic terminal of the present invention is obtained.

  Here, the height of the stepped portion 2c of the center conductor 2 (the length that is ½ of the difference between W1 and W2) is preferably 0.05 mm to 2 mm. If it is less than 0.05 mm, the step portion 2 c of the center conductor 2 may not be caught by the annular portion 3 d of the fixing bracket 3 due to the accuracy of brazing. On the other hand, if it exceeds 2 mm, the bonding area becomes too large, the wetting of the brazing material 5 becomes worse, and an airtight defect may occur.

  The protruding length of the annular portion 3d of the fixing bracket 3 from the inner peripheral surface of the inner cylinder 3b is such that the gap between the outer peripheral surface of the first portion 2a of the central conductor 2 and the inner peripheral surface of the inner cylinder 3b of the fixing metal 3 is first. It is desirable to design so as to be larger by about 0.05 mm than the gap between the outer peripheral surface of the second portion 2b and the annular portion 3d of the fixture 3. By doing so, the melted brazing material 5 flows into the gap between the annular portion 3d and the stepped portion 2c by capillary action, and the upper surface of the brazing material 5b is between the first portion 2a of the central conductor 2 and the fixing bracket 3. A meniscus can be formed in the gap so that the brazing material 5b does not creep up on the screw portion 2a 'above the blocking portion 3c.

  The position of the step portion 2 c formed on the center conductor 2 is preferably formed so that the lower end of the screw portion 2 a of the center conductor 2 is flush with the upper surface of the flat closing portion 3 cb of the fixing bracket 3. By doing so, when screwing with an external device, the end face of the mating female screw and the upper surface of the flat portion 3b can be brought into contact, and when the screw is loosened, it can be easily detected visually, Problems such as dropout can be prevented in advance.

  The hermetic terminal obtained in this way can be securely attached to an external device without the brazing material 5 creeping up on the threaded portion 2a ′, and has a strong bonding strength and durability against mechanical external forces. Excellent in properties.

  In addition, this invention is not limited to the example of the above embodiment, A various change is possible if it is the range which does not deviate from the summary of this invention. For example, a plurality of through holes 1 a may be formed in the ceramic insulator 1, and an airtight terminal in which the center conductor 2 is fixed to each through hole 1 a via the fixing fitting 3 may be used. The step portion 2c is formed perpendicular to the outer peripheral surface of the central conductor 2, but has an inclined tapered shape, and the annular portion 3d corresponds to the inner peripheral surface of the inner cylinder 3b. And may be inclined.

  In the description of the above embodiment, the terms “upper, lower, left and right” are merely used to describe the positional relationship in the drawings, and do not mean the positional relationship in actual use.

It is sectional drawing which shows an example of embodiment of the airtight terminal of this invention. It is a principal part expanded sectional view which expands and shows the brazing part in the airtight terminal of FIG. It is sectional drawing which shows the example of the conventional airtight terminal. It is sectional drawing which shows the other example of the conventional airtight terminal.

Explanation of symbols

1: Ceramic insulator 1a: Through hole 2: Central conductor 2a: First part 2b: Second part 2a ': Screw part
2c: Step part 3: Fixing metal fitting 3a: Outer cylinder 3b: Inner cylinder 3c: Closure part 3d: Annular part 4: Metallized layer
5: Brazing material

Claims (4)

A columnar center conductor having a first portion and a second portion whose thickness is thinner than the first portion, and a through hole through which the center conductor is inserted at the center, and around the opening of the through hole A cylindrical ceramic insulator on which a metallized layer is formed, and an inner cylinder is disposed inside the outer cylinder, and one end of the outer cylinder and the inner cylinder is closed between the outer cylinder and the inner cylinder. And the other end of the inner cylinder and a fixing bracket having an annular portion protruding toward the inner side of the inner cylinder, and the inner opening of the annular portion is seen from the axial extension line of the through hole. The other end of the outer cylinder and the metallized layer are brazed so as to be positioned within the opening range of the through hole, the central conductor passes through the inner cylinder and the through hole, and the first portion and the The step between the second part is brazed to the annular part Airtight terminal to be characterized. A cylindrical protrusion is provided at the opening of the through hole so as to be continuous with the through hole, and the inner peripheral surface of the outer cylinder is joined to the outer peripheral surface of the protrusion and the end surface of the ceramic insulator. The airtight terminal according to claim 1, wherein the airtight terminal is provided. 3. The airtight terminal according to claim 1, wherein the central conductor is made of stainless steel. An electric device comprising: an airtight container; and the airtight terminal according to any one of claims 1 to 3 attached to an outer wall of the airtight container.

Images