JP2014241195A - Surge absorber - Google Patents

Abstract

The present invention provides a surge absorber that can be manufactured at a low cost, has high joint reliability, is hardly affected by a conductor in an external environment, is small, and can suppress a continuity. An inner stem member made of a cylindrical metal, a single lead wire that is insulated and sealed with a sealing glass in the inner stem member and hermetically held in a penetrating state, and an inner stem member A metal inner cap electrode 5A that is hermetically sealed to the leading end side of the lead wire and a discharge space between the inner cap electrode and the inner cap electrode inside the inner cap electrode, and is fixed to the lead wire and out of the lead wire. An inner electrode electrode 6 having a large diameter, a cylindrical metal outer stem member 2B fixed to the outer side of the inner stem member via a sealing glass, and an inner cap electrode with a discharge space from the inner cap electrode And an outer cap electrode 5B made of metal fixed on the outer stem member. [Selection] Figure 1

Description

  The present invention relates to a surge absorber used for protecting various devices from a surge caused by a lightning strike or the like and preventing an accident in advance.

Portions where electronic devices for communication equipment such as telephones, facsimiles, modems, etc. are connected to communication lines, power lines, antennas, CRT drive circuits, etc. A surge absorber is connected to prevent damage due to thermal damage or ignition of an electronic device or a printed circuit board on which the device is mounted due to an abnormal voltage.
For example, the surge absorber includes a lightning arrester (arrester) that holds opposed electrodes in a sealed space, seals various gases in the space, and flows an abnormal voltage to ground by discharge between the electrodes.

As a conventional surge absorber, for example, Patent Document 1 describes a surge absorbing element having a structure in which opposing electrodes are isolated and held by insulating ceramics or glass. In this surge absorbing element, a hollow prism or cylindrical ceramic body (case member) is subjected to a so-called metallizing treatment by Mo-Mn layer and Ni plating on both ends, and cold-forged with 42 alloy or copper (lid) Member) and brazing with a silver-copper alloy (Telefunken method) to form a sealed space.
Patent Document 2 proposes an arrester in which a plurality of discharge chambers are connected in series and the overall arc discharge voltage is increased to a voltage at which no continuity occurs to prevent the continuation.

JP 2003-31337 A JP 09-92431 A

The following problems remain in the conventional technology.
The surge absorber described in Patent Document 1 requires a step of applying a dense Mo-Mn layer and Ni plating on both ends of the ceramic body for the purpose of bonding the ceramic body and the lid member serving as an electrode with high sealing performance. There is a problem that minor metals such as Mo, Mn, and Ni are required and the manufacturing cost increases.
Further, the insulating ceramic body occupies most of the outer surface area, and when a conductor such as a metal is close in the external environment, there is a disadvantage that the discharge performance is affected. For example, when a back electrode such as a circuit pattern is formed on the back surface of the substrate to be mounted, if the housing is an insulator, the electric field in the discharge space varies from the intended situation due to capacitive coupling with the internal electrode. There was a problem.
Furthermore, the technique disclosed in Patent Document 2 has a disadvantage in that since a plurality of discharge chambers are connected in series, the overall length becomes long, and the occupied area and volume on the substrate to be mounted increase. It was.

  The present invention has been made in view of the above-described problems, and can be manufactured at a low cost, can obtain high joint reliability, is hardly affected by a conductor in the external environment, and is a small-sized surge that can suppress a follow-up flow. The purpose is to provide an absorber.

  The present invention employs the following configuration in order to solve the above problems. That is, the surge absorber according to the first invention includes a cylindrical metal inner stem member, and one lead wire that is insulated and sealed with sealing glass in the inner stem member and is airtightly held in a penetrating state. A metal inner cap electrode fixed on the inner stem member and hermetically sealing a tip end side of the lead wire, and a discharge space between the inner cap electrode and the inner cap electrode in the inner cap electrode. An inner electrode portion fixed to a lead wire and having a larger outer diameter than the lead wire; a cylindrical metal outer stem member fixed to an outer peripheral side of the inner stem member via a sealing glass; and the inner cap And a metal outer cap electrode fixed on the outer stem member so as to cover the inner cap electrode with a discharge space from the electrode.

The surge absorber includes a metal outer cap electrode fixed on the outer stem member so as to cover the inner cap electrode with a discharge space with respect to the inner cap electrode. Two discharge spaces are formed in a layered manner with a cylindrical shape centered on the internal electrode portion. Therefore, by connecting the plurality of discharge spaces in series in the radial direction, the arc discharge voltage can be increased to suppress the continuity, and the size can be reduced.
In addition, there is an internal electrode part that is fixed to the lead wire with a discharge space between it and the inner cap electrode, and has a larger outer diameter than the lead wire. Thus, the overall structure is simple and the size can be reduced. In addition, since the cap electrode and the stem member are made of metal, they can be easily joined by various known methods, and high joining reliability can be obtained. In addition, there is no step of plating the end face of the ceramic body, and the use of minor metals such as Mo, Mn, and Ni can be reduced.
Further, since the outer cap electrode itself can be used as a mounting terminal, the height can be reduced in the mounted state and high mounting strength can be obtained. Therefore, compared to the case of standing by two lead wires, it is difficult to incline and can prevent contact with other surrounding parts, and is also resistant to vibrations and high reliability can be obtained.
Further, in this surge absorber, since the outer cap electrode serving as the housing is made of metal, it is possible to shield the influence of the electric field fluctuation due to the interaction with the conductor in the external environment.

A surge absorber according to a second invention is the surge absorber according to the first invention, wherein the inner cap electrode and the outer cap electrode are formed in a cylindrical shape with the lead wire disposed on a central axis, and the internal electrode portion is The lead wire is arranged on a central axis and is formed in a cylindrical shape.
That is, in this surge absorber, the inner cap electrode and the outer cap electrode are formed in a cylindrical shape with the lead wire disposed on the central axis, and the internal electrode portion is formed in a cylindrical shape with the lead wire disposed on the central axis. Because it is formed, a counter electrode with a coaxial structure can be configured, and the distance between the electrodes is the same in the axial direction. Therefore, the electric field at the center surface of the internal electrode section becomes stronger, and the discharge voltage can be controlled with a smaller distance between the electrodes. Is possible. Thereby, further miniaturization becomes possible. In addition, the facing area of the electrodes can be increased in a smaller space, which can contribute to discharge stability. In addition, since the discharge space has the same interval on the entire circumference, stable discharge characteristics can be obtained.

According to a third aspect of the present invention, the surge absorber according to the first or second aspect is formed between the inner stem member and the outer stem member that are coaxially arranged with each other, and a cylindrical metallic intermediate that is coaxial with the inner stem member and the outer stem member. At least one stem member is provided via the sealing glass, and between the inner cap electrode and the outer cap electrode, which are arranged coaxially with each other, a discharge space is formed coaxially with the inside and outside to seal the inside. A metal intermediate cap electrode is fixed on the at least one intermediate stem member.
That is, in this surge absorber, between the inner cap electrode and the outer cap electrode, a metal intermediate cap electrode that seals the inner side with a discharge space inside and outside is fixed on at least one intermediate stem member. Therefore, the discharge space is divided into three or more layers, and the arc discharge voltage can be further increased.

The present invention has the following effects.
That is, according to the surge absorber according to the present invention, since the metal cap cap is fixed on the outer stem member so as to cover the inner cap electrode with a discharge space from the inner cap electrode, By connecting the discharge spaces in series in the radial direction, the arc discharge voltage can be increased to suppress the continuity, and the size can be reduced.
In addition, a discharge space is provided between the inner cap electrode and the inner electrode part, which is fixed to the lead wire and has an outer diameter larger than that of the lead wire. Further, it is possible to obtain higher bonding reliability and to shield the influence of electric field fluctuation due to the interaction with the conductor in the external environment.

It is sectional drawing which shows 1st Embodiment of the surge absorber which concerns on this invention. In 1st Embodiment, it is a bottom view which shows a surge absorber. In 1st Embodiment, it is explanatory drawing which shows three types of mounting forms of a surge absorber. It is sectional drawing which shows 2nd Embodiment of the surge absorber which concerns on this invention. In 2nd Embodiment, it is a bottom view which shows a surge absorber.

  Hereinafter, a first embodiment of a surge absorber according to the present invention will be described with reference to FIGS. 1 to 3. In each drawing used for the following description, the scale is appropriately changed in order to make each member recognizable or easily recognizable.

  As shown in FIGS. 1 and 2, the surge absorber 1 according to the present embodiment is a cylindrical metal inner stem member 2A, and the inner stem member 2A is hermetically sealed with a sealing glass 3 and is airtight in a penetrating state. A lead wire 4 held on the inner stem member 2A, a metal inner cap electrode 5A which is fixed on the inner stem member 2A and hermetically seals the distal end side of the lead wire 4, and an inner cap electrode in the inner cap electrode 5A. An internal electrode portion 6 which is fixed to the lead wire 4 with a discharge space between the lead wire 4 and a larger outer diameter than the lead wire 4, and a cylinder fixed to the outer peripheral side of the inner stem member 2A via the sealing glass 3 A metal outer stem member 2B, and a metal outer cap electrode 5B fixed on the outer stem member 2B, covering the inner cap electrode 5A with a discharge space from the inner cap electrode 5A. Yes.

The internal electrode portion 6 is made of, for example, stainless steel, nickel, or white.
Further, the internal electrode portion 6 has an insertion hole for inserting the lead wire 4 on the central axis thereof, and the lead wire 4 is welded in a state of being inserted into the insertion hole.
The inner cap electrode 5A and the outer cap electrode 5B are formed in a cylindrical shape in which the lead wire 4 is arranged on the central axis and the upper part is closed, and the internal electrode portion 6 is arranged on the central axis. It is formed in a cylindrical shape.

The inner cap electrode 5A and the outer cap electrode 5B are made of, for example, Western white, and the inner stem member 2A and the outer stem member 2B are formed of iron-nickel alloy or the like.
The inner cap electrode 5A is set to have a smaller outer diameter and a lower height than the outer cap electrode 5B so that the inner cap electrode 5A can be accommodated in the outer cap electrode 5B with a space therebetween.
The surface of the outer cap electrode 5B is plated with a silver alloy or the like for easy mounting with a solder material or the like.

The inner cap electrode 5A has its lower part joined to the inner stem member 2A by press fitting, brazing, cold welding (cold welding), electric welding, etc. after evacuation or gas replacement, and the inner stem member 2A has a low melting point glass. A hermetic seal structure is obtained by being electrically insulated from the lead wire 4 hermetically welded by the sealing glass 3.
In addition, the outer cap electrode 5B has a lower portion joined to the outer stem member 2B by press fitting, brazing, cold welding (cold welding), electric welding, or the like after evacuation or gas replacement. A hermetic seal structure is obtained by being electrically insulated from the inner stem member 2A hermetically welded by the sealing glass 3 having a melting point glass.

In this way, when the inner cap electrode 5A and the outer cap electrode 5B are fixed to the inner stem member 2A and the outer stem member 2B, a heating process is not required, and thus it is easy to increase the pressure of the discharge control gas to be sealed. It is easy to obtain a high response voltage, and high voltage (high Vs) is easy.
Moreover, since a heating process becomes unnecessary, it becomes difficult to denature and degas by the heat | fever of the member currently used, and it becomes difficult to occur the unexpected discharge phenomenon.
The inside cap electrode 5A and the outside cap electrode 5B are in a state in which a vacuum or a discharge control gas is sealed.
The discharge control gas is He, Ar, Ne, Xe, SF ₆ , CO ₂ , C ₃ F ₈ , C ₂ F ₆ , CF ₄ , H ₂ , N ₂ , air (air), and a mixed gas thereof. .

  Note that a carbon trigger portion may be formed on the outer peripheral surface of the internal electrode portion 6. The trigger portion is a carbon trigger formed of a carbon material, and is formed in a linear shape or an elliptical membrane shape.

  As shown in FIG. 3, the surge absorber 1 is mounted with the lead wire 4 and the outer cap electrode 5B as connection terminals. That is, as shown in FIG. 3A, the lead wire 4 is joined to a wiring or the like on the substrate 100 such as a circuit board with a solder material or the like, and the lead wire 4 is bent to connect the outer cap electrode 5B to the substrate 100. The surge absorber 1 is mounted by joining the outer cap electrode 5B to a wiring or the like on the substrate 100 with a conductive fusing material 101 such as a solder material in a state of being tilted upward.

  If the back electrode 102 such as a circuit pattern is formed on the back side of the substrate 100, the electric field in the discharge space fluctuates from the intended situation due to capacitive coupling with the internal electrode when the housing is an insulator. However, in the surge absorber 1 of the present embodiment, since the outer cap electrode 5B serving as the housing is made of metal, there is no fear of such fluctuation. That is, the outer cap electrode 5B can shield the influence of the electric field fluctuation due to the interaction with the conductor in the external environment.

  Further, as shown in FIG. 3B, the lead wire 4 is joined to the substrate 100 with a solder material, the lead wire 4 is bent and the outer cap electrode 5B is brought down on the substrate 100, and the outer cap is further removed. The surge absorber 1 is mounted by joining one end of another lead wire 4B to the tip of the electrode 5B with a solder material or the like and joining the other end of the lead wire 4 to a wiring or the like on the substrate 100 with a solder material or the like. Is done. In the mounting forms shown in FIGS. 3A and 3B, the surge absorber 1 is mounted in a state of being tilted on the substrate 100, so that the height can be reduced.

  Further, as shown in FIG. 3 (c), the front end portion of the outer cap electrode 5B is joined to the wiring on the substrate 100 with a conductive fusing material 101 such as a solder material, and the lead wire 4 is bent. The surge absorber 1 is mounted in an inverted state by bonding to a wiring or the like on the folded substrate 100 with a solder material or the like. In the mounting form shown in FIGS. 3A and 3C, the outer cap electrode 5B itself is bonded onto the substrate 100 as a connecting terminal for mounting, so that it is not necessary to connect the lead wire 4 separately and is high. Mounting strength can be obtained. Moreover, even when mounted as shown in FIG. 3C, the influence between the lead wire 4 arranged along the outer cap electrode 5B is eliminated by the metal outer cap electrode 5B.

  In this surge absorber 1, when an overvoltage or overcurrent enters, if a trigger portion is provided, trigger discharge is first performed between the inner cap electrode 5 </ b> A and the trigger portion, and further, the discharge progresses and the internal electrode portion 6 is discharged in two discharge spaces between the central portion 6 and the inner cap electrode 5A and between the inner cap electrode 5A and the outer cap electrode 5B (a region surrounded by a two-dot chain line in FIG. 1). The surge is absorbed.

  As described above, the surge absorber 1 of the present embodiment includes the metal outer cap electrode 5B that is fixed on the outer stem member 2B so as to cover the inner cap electrode 5A with a discharge space from the inner cap electrode 5A. Therefore, at least two discharge spaces are formed in the inner cap electrode 5 </ b> A inside and outside in a layered manner with a cylindrical shape centering on the inner electrode portion 6. Therefore, by connecting the plurality of discharge spaces in series in the radial direction, the arc discharge voltage can be increased to suppress the continuity, and the size can be reduced.

  In addition, since the inner electrode electrode 6 is provided with an internal electrode portion 6 which is fixed to the lead wire 4 and has a larger outer diameter than the lead wire 4 with a discharge space between the inner cap electrode 5A and the cap itself. By using the electrodes, the overall structure is simple and the size can be reduced. In addition, since the cap electrode and the stem member are made of metal, they can be easily joined by various known methods, and high joining reliability can be obtained. Moreover, since Mo, Mn, Ni, etc. are not used for joining, use of these minor metals can be reduced.

Further, since the outer cap electrode 5B itself can be used as a mounting terminal, the height can be reduced in the mounted state and high mounting strength can be obtained. Therefore, compared to the case of standing by two lead wires, it is difficult to incline and can prevent contact with other surrounding parts, and is also resistant to vibrations and high reliability can be obtained.
Furthermore, since the outer cap electrode 5b serving as the casing is made of metal, it is possible to shield the influence of the electric field fluctuation due to the interaction with the conductor in the external environment.

  Further, the inner cap electrode 5A and the outer cap electrode 5B are formed in a cylindrical shape with the lead wire 4 disposed on the central axis, and the internal electrode portion 6 is formed in a columnar shape with the lead wire 4 disposed on the central axis. Since it is formed, a counter electrode having a coaxial structure can be formed, and the distance between the electrodes is the same in the axial direction. Therefore, the electric field at the center surface of the internal electrode portion 6 becomes strong, and the discharge voltage can be reduced with a smaller distance between the electrodes. Control becomes possible. Thereby, further miniaturization becomes possible. In addition, the facing area of the electrodes can be increased in a smaller space, which can contribute to discharge stability. In addition, since the discharge space has the same interval on the entire circumference, stable discharge characteristics can be obtained.

  The gap between the inner cap electrode 5A and the inner electrode portion 6 and the distance between the inner cap electrode 5A and the outer cap electrode 5B are narrowed and brought close to each other, so that the metal vapor generated by the discharge can be caused by the peripheral surface of the cap electrode or the inner electrode. Since it adheres to the part 6, it is difficult to adhere to the surface of the lower sealing glass 3, and the characteristic deterioration can be suppressed. Therefore, even if the discharge voltage is increased by increasing the gas pressure of the discharge control gas, the influence of the scattered metal vapor can be reduced.

  Next, a second embodiment of the surge absorber according to the present invention will be described below with reference to FIGS. Note that, in the following description of the embodiment, the same components described in the above embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  The difference between the second embodiment and the first embodiment is that in the first embodiment, the inner cap electrode 5A and the outer cap electrode 5B form a cylindrical two-layer discharge space. In the surge absorber 21 of the second embodiment, as shown in FIGS. 4 and 5, a metal intermediate cap that seals the inside with a discharge space inside and outside between the inner cap electrode 5 </ b> A and the outer cap electrode 5 </ b> B. The electrode 5C is provided to form a cylindrical three-layer discharge space.

That is, in the second embodiment, between the inner stem member 2 </ b> A and the outer stem member 2 </ b> B arranged coaxially with each other, a cylindrical metal intermediate stem member 2 </ b> C coaxial with these is interposed via the sealing glass 3. Is provided. Further, between the inner cap electrode 5A and the outer cap electrode, which are arranged coaxially with each other, a metal intermediate cap electrode 5C that is coaxial with these and opens the discharge space inside and outside to seal the inside is provided on the intermediate stem member 2C. It is fixed to. Therefore, the inner stem member 2A, the intermediate stem member 2C, and the outer stem member 2B are electrically insulated from each other by the sealing glass 3, and the inner cap electrode 5A, the intermediate cap electrode 5C, and the outer cap electrode have a discharge space from each other. Is electrically insulated.
The intermediate stem member 2C is formed of the same metal material as the inner stem member 2A, and the intermediate cap electrode 5C is formed of the same metal material as the inner cap electrode 5A.

As described above, in the surge absorber 21 according to the second embodiment, the intermediate cap member 5C made of metal that seals the inner side with a discharge space between the inner cap electrode 5A and the outer cap electrode 5B is provided between the inner cap electrode 5A and the outer cap electrode 5B. Since it is fixed on 2C, the discharge space can be divided into three layers to further increase the arc discharge voltage.
Two or more intermediate stem members 2C and intermediate cap electrodes 5C having different outer diameters may be further provided coaxially to form discharge spaces in the radial direction in four or more stages.

  The technical scope of the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention.

  DESCRIPTION OF SYMBOLS 1,21 ... Surge absorber, 2A ... Inner stem member, 2B ... Outer stem member, 2C ... Intermediate stem member, 3 ... Sealing glass, 4 ... Lead wire, 5A ... Inner cap electrode, 5B ... Outer cap electrode, 5C ... Intermediate cap, 6 ... Internal electrode

Claims (3)

A cylindrical metal inner stem member;
One lead wire that is insulated and sealed with sealing glass in the inner stem member and is kept airtight in a penetrating state;
A metal inner cap electrode that is fixed on the inner stem member and hermetically seals the distal end side of the lead wire;
An internal electrode portion having a larger outer diameter than the lead wire, which is fixed to the lead wire with a discharge space between the inner cap electrode and the inner cap electrode;
A cylindrical metal outer stem member fixed to the outer peripheral side of the inner stem member via a sealing glass;
A surge absorber comprising: a metal outer cap electrode fixed on the outer stem member so as to cover the inner cap electrode with a discharge space from the inner cap electrode. The surge absorber according to claim 1,
The inner cap electrode and the outer cap electrode are formed in a cylindrical shape with the lead wires arranged on a central axis,
A surge absorber characterized in that the internal electrode portion is formed in a columnar shape with the lead wire disposed on a central axis. The surge absorber according to claim 1 or 2,
Between the inner stem member and the outer stem member arranged coaxially with each other, at least one cylindrical metal intermediate stem member coaxial with these is provided via a sealing glass,
Between the inner cap electrode and the outer cap electrode arranged coaxially with each other, there is at least one intermediate stem member made of metal that seals the inner side with a discharge space inside and outside coaxially with the inner cap electrode. Surge absorber characterized by being fixed on the top.

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