JP2008027630A - Hermetic seal with cementation prevention glass holding mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hermetic seal with cementation prevention glass holding mechanism devised to eliminate cementation of a metallic holding component by realizing hermetic seal without using a carbon jig. <P>SOLUTION: The hermetic seal in which a glass tube 12 is inserted into a hole 11d made penetrated into a holding component 11 made of a metal member and a connecting pin 13 is inserted into the glass tube and heated as it is erected on the jig 15 to melt the glass tube, and an inner periphery face of the hole of the holding component and an outer periphery face of the connecting pin are tightly adhered to each other to seal them is provided with a holding mechanism for holding the glass tube 12 in the hole 11d of the holding component as the holding component is erected on the jig. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a hermetic seal, and more particularly to a hermetic seal with a carburization-preventing glass holding mechanism.

  As is well known, hermetic seals are suitable for sealing sensors and other devices that need to maintain liquid tightness such as in places where high pressure is applied, or that require high airtightness such as vacuum vessels. It has a structure in which a holding part (shell or case) made of a metal member such as steel (hereinafter referred to as “SUS”) and a connection pin are baked and hardened with glass (glass). For this reason, it is applied to seals of connection terminals (connection pins) of sensors that have extremely high reliability and require high pressure resistance, high liquid tightness, high air tightness, high insulation, and the like.

  3 and 4 show a case where the connection pin is sealed to a metal holding part to which a conventional hermetic seal is applied. The holding component 1 has a cylindrical shape, and a plurality of, for example, four holes 1a are penetrated along the axial direction and at equal intervals in the circumferential direction. A glass tube 2 is inserted into each hole 1a. Each of the connection pins 3 is inserted and inserted.

  The jig 5 has a circular recess 5b in which the lower part of the holding component 1 is fitted to the upper surface 5a, and a cylindrical protrusion that protrudes from the bottom surface 5c of the recess 5b and fits in the lower end of each hole 1a of the holding component 1. (Boss) 5d and a positioning pin hole 5e for inserting the connection pin 3 into the center of the protrusion 5d and determining the protruding length of the connection pin 3 are formed. The jig 6 is attached to the upper end of the holding component 1 and has a positioning pin hole 6 a corresponding to each connection pin 3.

  The holding component 1 is held with its lower portion standing and fitted in the concave portion 5b of the jig 5, the entire lower surface 1b abuts against the bottom surface 5c of the concave portion 5b, and the lower outer peripheral surface extends over the entire circumferential surface of the concave portion 5b. The protrusion 5d is fitted to the lower end of the hole 1a in contact with the inner peripheral surface. The glass tube 2 is inserted into the hole 1a of the holding component 1 and dropped by its own weight, and the lower end surface is supported by being in contact with the upper surface of the protrusion 5d. The connecting pin 3 is inserted into the pin hole 5e of the glass tube 2 and the jig 5, is dropped by its own weight, and the lower end surface contacts the bottom surface of the hole 5e and is positioned.

  Then, the jig 6 is attached to the holding part 1 and the upper portion of the connection pin 3 is inserted into the pin hole 6a and positioned, and then carried into the electric furnace and heated to a predetermined high temperature. The glass tube 2 is melted by heating and is brought into close contact with the inner peripheral surface of the hole 1 a of the holding component 1 and the outer peripheral surface of the connection pin 3 to seal between the holding component 1 and the connection pin 3.

  By the way, environmental problems have been regarded as important in recent years, and lead glass having a low melting temperature has been avoided as a glass tube of a hermetic seal. For this reason, borosilicate glass or the like is used as the glass used for the hermetic seal, and a high sealing temperature (melting temperature) is required, which is often about 900 ° C. or higher.

  For this reason, the jig 5 that determines the positional relationship between the holding component 1 made of a metal member and the glass tube 2 is required to be made of a material that is excellent in heat resistance and does not adhere to the molten glass. A jig (hereinafter referred to as “carbon jig”) is used. Note that the jig 6 may be usually formed of a metal member such as SUS in order not to contact the molten glass.

For example, a method for manufacturing an airtight terminal has been proposed as an application of a hermetic seal (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 4-10372 (page 2, FIG. 4)

  However, when a carbon jig is used as the jig 5 for determining the positional relationship between the holding part 1 made of a metal member such as SUS and the glass tube 2, the bottom surface contacting the jig 5 of the holding part 1 as shown by a thick line in FIG. 1b and the lower part of the outer peripheral surface are often carburized. The carburized holding component 1 causes problems in oxide film removal and welding performed as a post-process of hermetic sealing. For example, there is a problem that the carburized portion of the holding part 1 is easily broken when the holding part 1 is welded to another part. Moreover, since the carbon jig is a consumable item, the cost increases.

  Further, the technique disclosed in Patent Document 1 relates to a method of manufacturing an airtight terminal whose glass sealing height is 2.5 times or more larger than the inner diameter of the metal outer ring. There is no description of carburization of the ring.

  It is an object of the present invention to provide a hermetic seal with a carburization-preventing glass holding mechanism that realizes a hermetic seal without using a carbon jig and eliminates carburization of metal holding parts.

  In order to solve the above-described problems, a hermetic seal with a carburization-preventing glass holding mechanism according to the present invention includes a glass tube inserted into a hole penetrating a holding part made of a metal member, and a connection pin inserted into the glass tube. A hermetic seal that heats up and melts the glass tube so that the inner peripheral surface of the hole of the holding component and the outer peripheral surface of the connection pin are in close contact with each other, and the holding component is attached to the jig. A glass holding mechanism for holding the glass tube is provided in the hole of the holding component when standing.

  When the glass tube inserted into the hole of the holding component is held in the hole by the glass holding mechanism and the holding component is erected on the jig, the glass tube is prevented from falling out of the hole. Thereby, when the glass tube at the time of hermetic sealing is melted, it does not come into contact with the jig, and it is completely prevented from coming into close contact with the jig. Thereby, a metal member can be used for a jig, and carburizing of holding parts can be completely eliminated when performing hermetic sealing.

  In addition, the hermetic seal with a carburization-preventing glass holding mechanism according to claim 2 of the present invention is the hermetic seal with a carburization-preventing glass holding mechanism according to claim 1, wherein the glass holding mechanism has a lower end of a hole of the holding part. The portion is formed concentrically with a diameter slightly smaller than the outer diameter of the glass tube and larger than the outer diameter of the connection pin, and supports the lower end surface of the glass tube.

  The lower end portion of the hole of the holding part is slightly reduced in diameter to form a stepped portion, and the lower end surface of the glass tube inserted into the hole is brought into contact with its own weight and locked. Thereby, it can hold | maintain, without dropping a glass tube in the hole of holding components.

  In addition, the hermetic seal with a carburization-preventing glass holding mechanism according to claim 3 of the present invention is the hermetic seal with a carburization-preventing glass holding mechanism according to claim 1, wherein the glass holding mechanism is located above the hole of the holding part. A hole having a diameter larger than that of the hole is formed in a concentric manner, and a large diameter portion that can be fitted in the upper hole of the holding part is formed in a concentric step on the upper end portion of the glass tube. It is formed and locked in the step of the hole, and is held in the hole.

  The upper part of the glass tube is formed at the upper step part of the hole by forming the step part with the upper part of the glass tube having a slightly larger diameter. Are brought into contact with each other by their own weight and locked. Thereby, it can hold | maintain, without dropping a glass tube in the hole of holding components.

  In addition, the hermetic seal with a carburization-preventing glass holding mechanism according to claim 4 of the present invention is the hermetic seal with a carburization-preventing glass holding mechanism according to any one of claims 1 to 3, wherein the jig is a metal member. It is characterized by being formed by.

  When the glass tube is melted and hermetic sealing is performed, the jig for standingly holding the holding component is formed of a metal member, so that the carburization of the holding component can be completely eliminated. Moreover, the carbon jig as a consumable can be reduced.

  According to the present invention, a hermetic seal between the holding part and the connection pin can be realized without using a carbon jig, and the carburization of the holding part can be completely eliminated and the carbon jig as a consumable can be reduced. Therefore, it is possible to reduce the equipment cost in combination with the cost reduction.

  Further, by preventing carburization of the holding parts, it is possible to prevent problems in oxide film removal, welding, and the like performed as a post-hermetic seal process. In addition, the glass tube can be held in the hole of the holding component with a simple configuration, and workability can be improved.

  Hereinafter, a first embodiment of a hermetic seal with a carburization-preventing glass holding mechanism according to the present invention will be described with reference to the drawings. As shown in FIG. 1, the holding component 11 has a cylindrical shape, and a large-diameter concave portion 11b is formed concentrically on the upper surface 11a. The bottom surface 11c of the concave portion 11b is equidistant along the axial direction and in the circumferential direction. A plurality of, for example, four holes 11d are formed. The hole 11 d has a predetermined inner diameter, and the lower end portion 11 e has a slightly smaller diameter and a larger diameter than the outer diameter of the connection pin 13. That is, the hole 11d is a stepped hole having a slightly lower diameter concentrically at the lower end 11e. A step portion 11 f between the hole 11 d and the lower end portion 11 e is a glass holding mechanism that holds the glass tube 12. The holding component 11 is formed of a metal member such as SUS having excellent heat resistance, pressure resistance, weather resistance, and the like.

  The glass tube 12 as the sealing glass can be inserted into the hole 11d of the holding part 11 with an extremely small outer diameter (clearance) and is slightly larger than the inner diameter of the lower end portion 11e of the hole 11d. The length is set slightly shorter than the depth from the upper end of the hole 11d to the step portion 11f. Thereby, when the glass tube 12 is inserted into the hole 11d, the lower end surface is locked and held by the step portion 11f with the lower end portion 11e so that the glass tube 12 does not fall out and does not protrude from the hole 11d when melted. Has been. The glass tube 12 is made of, for example, borosilicate glass.

  The connection pin 13 has a predetermined length longer than the length of the holding component 11 and is formed to have an outer diameter that can be inserted into the glass tube 12 with a very small gap (clearance). The connection pin 13 is formed of a metal member such as Kovar, for example. The connection pin 13 is further subjected to other metal plating such as gold plating according to the specification after the hermetic seal is finished.

  The jig (die) 15 has a disk shape larger in diameter than the holding component 11, and the recess 15 b and the recess 15 c are formed concentrically on the upper surface 15 a in sequence. The recess 15b has an inner diameter into which the lower end of the holding component 11 is fitted, and is formed shallow. The recess 15 c has a slightly smaller diameter than the recess 15 b and is formed to the same depth as the length of the connection pin 13 protruding from the lower surface of the holding component 11. Further, the width of the step portion 15d between the concave portion 15b and the concave portion 15c is formed narrow. Thereby, when the holding component 11 is mounted on the jig 15, the contact area between the lower peripheral portion of the outer peripheral surface and the lower surface 11g of the holding component 11 and the inner peripheral surface of the concave portion 15b of the jig 15 and the step portion 15d is reduced. Is possible.

  The jig 15 is made of a metal member such as nickel. When the holding part 11 is formed of a SUS member as described above, the jig 15 is formed of nickel other than SUS, so that the heat diffusion bonding between the holding part 11 and the jig 15 is performed when the glass tube 12 is heated to melt. Can be effectively prevented.

  Instead of forming the concave portion 15b of the jig 15 shallowly and narrowing the width of the step portion 15d between the concave portion 15b and the concave portion 15c, the inner peripheral surface of the concave portion 15b and the upper surface of the step portion 15d are respectively along the circumferential direction. Protrusions with small tips may be formed at a plurality of places, for example, three places at intervals, and these protrusions may support the lower portion of the outer peripheral surface of the holding component 11 and the peripheral portion of the lower surface 11g with substantially point contact. This is effective because the contact area between the jig 15 and the holding component 11 can be made extremely small.

  The jig (mold) 16 has a disk shape substantially the same diameter as the jig 15, and a circular concave portion 16 b and a concave portion 16 c are formed concentrically with a step on the lower surface 16 a. The recess 16b is formed shallow so that the upper end of the holding component 11 can be slightly fitted. The concave portion 16c has a slightly smaller diameter than the concave portion 16b, and a step portion 16d with the concave portion 16b is formed narrower. The bottom surface 16e of the recess 16c is formed with a positioning pin hole 16f for positioning by inserting them into positions corresponding to the connection pins 13 projecting upward from the holding component 11.

  Since the recess 16b is formed shallow, the width of the inner peripheral surface thereof is reduced, the contact area with the upper end of the outer peripheral surface of the holding component 11 can be reduced, and the inner diameter of the recess 16c is made larger than the inner diameter of the recess 16b. In addition, the contact area with the peripheral edge portion of the upper surface 11a of the holding component 11 can be reduced by slightly reducing the width of the annular stepped portion 16d.

  In addition, protrusions with small tips are formed at a plurality of, for example, three locations at equal intervals along the circumferential direction on the inner peripheral surface of the concave portion 16b and the lower surface of the stepped portion 16d, respectively, You may make it support the peripheral part of the upper surface 11a by a substantially point contact. Similar to the jig 15, the jig 16 is formed of a metal member such as nickel. In addition, the holding component 11 and the jigs 15 and 16 may have a structure having the same function even in a polygonal shape such as a square in a plan view as well as a circle in a plan view.

  Next, the hermetic seal having the above configuration will be described. As shown in FIG. 1, the lower end portion of the holding component 11 is fitted into the concave portion 15c of the jig 15, and the glass tube 12 is inserted into the hole 11d from above. The glass tube 12 is locked by its own weight with its lower end surface coming into contact with and engaging with the stepped portion 11f of the lower end portion 11e of the hole 11d. That is, the glass tube 12 is prevented from falling out of the hole 11 d by the holding mechanism formed in the holding component 11, and the lower end surface is held at a slightly inward (upper) position than the lower surface 11 g of the holding component 11. Moreover, the upper end of the glass tube 12 is located in the vicinity of the upper end of the hole 11d.

  Next, the connection pin 13 is inserted into the glass tube 12 from above. The connection pin 13 is positioned with its lower end surface coming into contact with the bottom surface 15e of the recess 15c of the jig 15 by its own weight. Alternatively, the connection pin 13 may be inserted into the glass tube 12 in advance, and the glass tube 12 and the connection pin 13 may be simultaneously inserted into the hole 11 d of the holding component 11.

  Then, the jig 16 is attached to the upper end of the holding component 11, and the upper portion of the connection pin 13 is inserted into the positioning hole 16f for positioning. Thus, in the state (initial state) in which the holding component 11 is attached to the jig 15, the glass tube 12 has the lower end surface positioned inside the lower surface 11g in the hole 11d of the holding component 11 and the bottom surface of the recess 15c of the jig 15. It is held at a large distance from 15e.

  Next, these are carried into an electric furnace (not shown) and heated to a predetermined temperature. When the glass tube 12 reaches a predetermined temperature, it melts and adheres closely to the inner peripheral surface of the hole 11 d and the outer peripheral surface of the connection pin 13. The molten glass flows slightly into the lower end portion 11e of the hole 11d, but has high viscosity and does not flow out of the lower end portion 11e due to the action of surface tension. Therefore, the glass does not protrude from the lower surface 11 g of the holding component 11.

  Furthermore, the holding component 11 has a peripheral surface of the lower surface 11g placed on a step portion 15d between the concave portions 15b and 15c of the jig 15, and the lower surface 11g is separated from the bottom surface 15e of the concave portion 15c by the protrusion of the connection pin 13. It is possible to completely prevent the glass melted in close contact with the bottom surface 15e of the jig 15.

  Further, the glass tube 12 is set to have a length shorter than the depth from the upper end of the hole 11d to the stepped portion 11f, so that it does not flow out from the upper end of the hole 11d. Thereby, the connection pin 13 can be hermetically sealed to the holding component 11 in a state as shown in FIG.

  After the hermetic sealing is completed as described above, the holding component 11 is taken out from the jigs 15 and 16. Since the jig 15 is formed of a metal member such as nickel, the carburizing of the holding part 11 is completely eliminated when performing hermetic sealing. Further, thermal diffusion bonding between the holding component 11 and the jig 15 is also prevented. Thus, according to the present invention, a hermetic seal can be realized without using a carbon jig, and carburization of the metal holding part 11 can be completely eliminated and the number of carbon jigs can be reduced.

  Further, the glass holding mechanism for holding the glass tube 12 only needs to form the lower end portion 11e of the hole 11d of the holding component 11 with a slightly small diameter, and the glass tube 12 cuts a long glass tube into a predetermined length. It is possible to cope only with this, and the configuration is extremely simple.

  FIG. 2 shows a second embodiment of a hermetic seal with a carburization-preventing glass holding mechanism according to the present invention. In FIG. 2, the same or corresponding members as those shown in FIG. 1 are denoted by the same or corresponding reference numerals, and detailed description thereof is omitted. As shown in FIG. 2, a hole 11h having a diameter slightly larger than that of the hole 11d and having a predetermined depth is formed concentrically above the hole 11d of the holding component 11, and the hole 11d and the hole 11h are formed concentrically. It is connected with a step. That is, the hole 11d is a stepped hole having a concentric upper part and a slightly large diameter hole 11h.

  On the other hand, the glass tube 22 has an outer diameter at which the upper end portion 22a can be inserted into the hole 11h with a slight clearance (clearance), and the tube portion 22b which is the lower portion, that is, the main portion from the upper end portion 22a is slightly formed in the hole 11d. It can be inserted in a gap (clearance). That is, the glass tube 22 has a stepped upper end 22a. In the glass tube 22, the length of the upper end portion 22a is slightly shorter than the depth of the hole 11h, and the length of the tube portion 22b is the depth from the step portion 11i of the hole 11d to the lower surface 11g of the holding component 11, that is, the hole 11d. It is formed slightly shorter than the depth. Such a glass tube 22 is obtained by, for example, compression-molding a mixture of glass powder and a small amount of a binder in a mold and then sintering in a furnace.

  The glass tube 22 is inserted into the hole 11c of the holding component 11 by the step portion 11i between the hole 11d and the upper hole 11h of the holding component 11 and the step portion 22c between the upper end portion 22a and the tube portion 22b of the glass tube 22. A glass holding mechanism for holding is configured.

  Then, the holding component 11 is erected on the jig 15, and the glass tube 22 is inserted into the hole 11h and the hole 11d from above. In the glass tube 22, the upper end portion 22a is inserted into the hole 11h, the tube portion 22b is inserted into the hole 11d, and the stepped portion 22c is brought into contact with the stepped portion 11i of the holding component 11 by its own weight and is held and held in that position. . That is, the glass tube 22 is locked and held in the hole 11 d of the holding component 11 to prevent it from falling off, and the lower end surface is held slightly inward from the lower surface 11 g of the holding component 11. Further, the upper end portion 22a of the glass tube 12 is located in the vicinity of the upper portion of the hole 11h.

  Next, the connection pin 13 is inserted into the glass tube 22 from above. The connection pin 13 is positioned with its lower end surface coming into contact with the bottom surface 15e of the recess 15c of the jig 15 by its own weight. Alternatively, the connection pin 13 may be inserted into the glass tube 22 in advance, and the glass tube 22 and the connection pin 13 may be simultaneously inserted into the hole 11 c of the holding component 11.

  Then, the jig 16 is attached to the upper end of the holding component 11, and the upper portion of the connection pin 13 is inserted into the positioning hole 16f for positioning. Thus, in a state (initial state) in which the holding component 11 is attached to the jig 15, the lower end surface of the glass tube 22 is positioned on the inner side of the lower surface 11g of the holding component 11 and is greatly separated from the bottom surface 15e of the recess 15c of the jig 15. Is held.

  Next, these are carried into an electric furnace (not shown) and heated to a predetermined temperature. When the glass tube 22 reaches a predetermined temperature, it melts and comes into close contact with the inner peripheral surfaces of the holes 11 d and 11 h and the outer peripheral surface of the connection pin 13. The length of the tube portion 22b of the glass tube 22 is formed slightly shorter than the depth of the hole 11d, and the molten glass flows out from the lower end of the hole 11d due to its high viscosity and the action of surface tension. There is nothing. Therefore, the molten glass does not protrude from the lower surface 11 g of the holding component 11. And it is completely prevented that the holding | maintenance component 11 and the jig 15 adhere | attach with the molten glass.

  The time required to hold the glass tube in the hole 11d of the holding component 11 is from the time when the glass tube 12 is inserted into the hole 11d until it is melted. Accordingly, as described above, as the glass holding mechanism for locking and holding the glass tube 12 in the hole 11d of the holding part 11, the step portion 11f is formed at the lower end portion 11e of the hole 11d, or the hole 11h above the hole 11d and the glass It is not restricted to the structure which each forms the step part 11i, 22c in the upper end part 22a of the pipe | tube 22, For example, it protrudes slightly toward the inner radial direction at the lower end opening end of the other hole 11d, for example, along the circumferential direction A plurality of, for example, caulking (indentations) may be formed at at least three locations at equal intervals to hold the lower end surface of the glass tube. Further, a metal O-ring or a washer having an inner diameter larger than the outer diameter of the connection pin 13 may be fitted to the lower end of the hole 11d. Alternatively, the diameter of the lower end of the hole 11d may be slightly tapered.

  Further, in the first and second embodiments, the step part 11f between the hole 11d and the lower end part 11e of the holding part 11 forming the glass holding mechanism, the step part 11i between the upper part of the hole 11d and the hole 11h, and the glass tube 22 Of course, the step portion 22c between the upper end portion 22a and the tube portion 22b is not limited to a flat surface but may be a tapered surface.

It is sectional drawing which shows 1st Embodiment of the hermetic seal with a carburization prevention glass holding mechanism concerning this invention. It is sectional drawing which shows 2nd Embodiment of the hermetic seal with a carburization prevention glass holding mechanism concerning this invention. It is a top view which shows an example of the holding components to which the conventional hermetic seal is applied. It is explanatory drawing in the case of carrying out a hermetic seal of the connection pin to the holding component shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Holding component 1a Hole 1b Lower surface 2 Glass tube 3 Connection pin 5 Jig 5a Upper surface 5b Recess 5c Bottom 5d Projection 5e Positioning pin hole 6 Jig 6a Positioning pin hole 11 Holding component 11a Upper surface 11b Recess 11c Bottom 11d Hole 11d Portion 11f Stepped portion 11g Lower surface 11h Hole 11i Stepped portion 12 Glass tube 13 Connection pin 15 Jig 15a Upper surface 15b, 15c Recessed portion 15d Stepped portion 15e Bottom surface 16 Jig 16a Lower surface 16b, 16c Recessed portion 16d Stepped portion 16e Bottom surface pin 16f Glass tube 22a Upper end portion 22b Tube portion 22c Stepped portion

Claims (4)

Insert a glass tube into a hole penetrating through a holding part made of a metal member, insert a connection pin into the glass tube, erect it on a jig and heat it to melt the glass tube, and the inner peripheral surface of the hole of the holding part And a hermetic seal that seals closely to the outer peripheral surface of the connection pin,
A hermetic seal with a carburization-preventing glass holding mechanism, comprising a glass holding mechanism for holding the glass tube in a hole of the holding part when the holding part is erected on the jig.   The glass holding mechanism is formed such that the lower end of the hole of the holding component is concentrically formed with a diameter slightly smaller than the outer diameter of the glass tube and larger than the outer diameter of the connection pin, and the lower end surface of the glass tube The hermetic seal with a carburization-preventing glass holding mechanism according to claim 1, wherein   The glass holding mechanism has a hole having a diameter larger than the hole formed concentrically at the upper part of the hole of the holding part, and is fitted to the upper hole of the holding part at the upper end of the glass tube. The hermetic seal with a carburization-preventing glass holding mechanism according to claim 1, wherein a possible large diameter portion is formed concentrically with a step, is locked to the step of the hole, and is held in the hole. The hermetic seal with a carburization-preventing glass holding mechanism according to any one of claims 1 to 3, wherein the jig is formed of a metal member.

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