JPH0650954Y2 - Surge absorber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention is a discharge type sanjinge absorption element that absorbs surge such as induced lightning applied to a telephone circuit or the like due to a discharge phenomenon of a discharge gap enclosed in an airtight container. The present invention relates to a surge absorber in which overcurrent interruption means is connected in series, and more particularly, to a surge absorber having improved safety by preventing continuation of arc discharge in a discharge type surge absorbing element.

[Prior Art] A type of discharge type surge absorbing element 2, which is widely known as a gas arrester, has lead wires 5, 5 connected to a pair of discharge electrodes 4, 4 as shown in FIG. The discharge gaps 4 are formed between the discharge electrodes 4 and 4 and are sealed together with the discharge gas in a hermetic container 7 made of glass, and the lead wires 5 and 5 are placed outside the hermetic container 7. It has the structure derived to.

The discharge type surge absorbing element is used by being connected to a telephone line or the like, and when a surge such as an induced lightning is applied to this, a discharge is generated in the discharge gap to absorb the surge,
It has a function of preventing surge from entering a telephone or the like. Since the surge absorption is due to the arc discharge in the discharge gap, it is possible to absorb a considerably large surge.

[Problems to be solved by the invention] By the way, telephones are overvoltage tested by safety standards such as CSA and UL.

This overvoltage test assumes a case where a power line comes into contact with a telephone line, and applies an AC voltage exceeding the rated voltage (DC discharge start voltage) of the discharge type surge absorbing element. Therefore, when the above-mentioned overvoltage test is performed, the applied AC voltage causes the arc discharge between the discharge electrodes to be in a continuous state, and the discharge electrodes are melted and short-circuited. Further, the heat also melts the airtight container and entangles with the discharge electrode, and eventually the circuit board on which the discharge type surge absorbing element is mounted is burned out. This causes the overvoltage test to fail. In addition, if the above-mentioned phenomenon occurs during use, a fire may occur.

The present invention has been devised in view of the above-mentioned point, and even when the arc discharge is in a continuous state at the time of an overvoltage test or a line accident according to the safety standard, the arc discharge occurs before the discharge electrode is melted and short-circuited. The purpose is to prevent a burnout accident by shutting off the power and to realize a highly safe surge absorber that complies with safety standards.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the surge absorber of the present invention comprises:
A strip heating resistor formed on the insulating substrate and a groove formed on the insulating substrate that is ruptured by thermal shock of the strip heating resistor generated by continuous overcurrent energization and that crosses the strip heating resistor. Discharge type surge absorption in which the discharge current electrodes, which are connected in series with the above-mentioned strip-shaped heating resistor and which are opposed to each other with a discharge gap, are hermetically sealed together with the discharge gas. It is characterized by comprising an element.

Further, the strip-shaped heating resistor is divided into a plurality of parts, and a good electrical conductor is interposed between adjacent strip-shaped heating resistors, and the strip-shaped heating resistor and the good electrical conductor are alternately arranged in series. It may be a structure. In addition, a structure in which the electrical good conductor, the strip heating resistor, and the electrical good conductor are laminated in this order at the joint between the strip heating resistor and the electrical good conductor may be used.

Further, the strip-shaped heating resistor attached to the insulating plate may be covered with lead-free glass.

[Operation] The surge absorber of the present invention comprises a strip-shaped heating resistor formed on the insulating substrate and the strip-shaped heating resistor formed on the insulating substrate and crushed by thermal shock of the strip-shaped heating resistor. Since an overcurrent interrupting means consisting of a groove-shaped thermally destructible portion traversing and a discharge type surge absorbing element in which discharge electrodes opposed to each other across a discharge gap are hermetically sealed together with discharge gas are connected in series, Arc discharge is generated in the surge absorption element, the amount of current increases, and if this overcurrent is sustained,
The band-shaped heating resistor rapidly generates heat, and thermal shock is applied to the insulating substrate. Then, the thermal shock to the insulating substrate breaks the insulating substrate at the thermally destructible portion and cuts the strip-shaped heating resistor that is a current path to interrupt the arc discharge.

Further, when the strip-shaped heating resistor of the overcurrent interrupting means is divided into a plurality of parts and electrically good conductors are interposed between the adjacent divided resistors, if they are connected in series alternately, High voltage such as surge applied to the resistor
The voltage is divided into lower voltages according to the number of divided resistors. As a result, when a high voltage such as a surge is applied to a single resistor, if an inhomogeneous portion exists in a part of the resistor, current concentrates only in a part of the resistor and the resistor burns out. The risk will be reduced.

Further, by laminating the joint portion between the strip heating resistor and the electrical good conductor with the electrical good conductor, the strip heating resistor, and the electrical good conductor, the contact area between the strip heating resistor and the electrical good conductor is increased, Contact resistance is reduced.

Then, by covering the strip-shaped heating resistor adhered to the insulating substrate with deleaded glass, it is possible to prevent the generation of creeping discharge on the surface of the resistor even when a high voltage such as a surge is applied. it can.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing a surge absorber according to an embodiment of the present invention, FIG. 2 is an equivalent circuit diagram showing a surge absorber of the present invention, and FIG. 3 is a schematic side view of an embodiment of the present invention. FIG. 4 is a schematic sectional view of a discharge type surge absorber used in an embodiment of the present invention, FIG. 5 is a schematic rear view of an embodiment of the present invention, and FIG.
FIG. 7 is a schematic rear view of another embodiment of the present invention, and FIG. 7 is a schematic cross-sectional view of an overcurrent interruption means of the present invention. In the figure, reference numeral 1 denotes a surge absorber, which is configured by connecting a discharge type surge absorbing element 2 on an overcurrent interruption means 3 in series.

As shown in FIG. 4, the discharge type surge absorbing element 2 has a surface made of nickel or the like having a good discharge characteristic of BaO or BaO.
.Connecting lead wires 5 and 5 made of Dumet wire to the base ends of the pair of rod-shaped discharge electrodes 4 and 4 formed by covering with an emitter material such as Al ₂ O ₃ and facing them in parallel with each other. To form a discharge gap 6 between the discharge electrodes 4 and 4, and further to dispose both ends of the glass tube together with a discharge gas mainly containing an inert gas such as a rare gas such as Ne, Ar or He or a nitrogen gas. The lead wires 5 and 5 are led out of the airtight container 7 by enclosing it in an airtight container 7 formed by sealing.

The overcurrent interruption means 3 is made of ceramics such as alumina, forsterite, steatite, etc. and has a thickness of 0.5.
A strip-shaped heating resistor 9 made of ruthenium-based paste or the like is adhered and formed on one surface of an insulating substrate 8 of up to 1.5 mm in a meandering shape having a bent portion.
When lead-out electrodes 10a and 10b made of a good electrical conductor such as Ag / Pd paste are adhered to both end portions of and the overcurrent is continuously applied to the substantially central portion of the other surface of the insulating substrate 8. Further, a thermal destructible portion 11 having a groove-like thin shape that crushes the insulating substrate 8 in the left-right direction by the thermal shock generated in the strip heating resistor 9 is formed across the strip heating resistor 9.

The strip heating resistor 9 is bent in a meandering manner on the insulating substrate 8 so that the resistance value between both ends of the strip heating resistor 9 is within the range of 1Ω to 300Ω in accordance with the test conditions in various safety standards. By doing so, the length is appropriately set. Also,
As shown in FIG. 5, when the strip-shaped heating resistor 9 is adhered and formed, the thickness of the strip-shaped heating resistor 9 is 10 μm to 25 μm.
It is preferable that the width is about 0.5 mm to 10 mm.

Then, the insulating substrate 8 is passed through the lead-out electrode 10a to fix the external terminal 12a by soldering or the like, and one of the lead wires 5 and 5 of the discharge type surge absorbing element 2 is connected to the insulating substrate 8. Similarly, the lead wires 5 and 5 are fixed to the lead-out electrode 10b by soldering, and the other of the lead wires 5 and 5 is fixed to the other surface of the insulating substrate 8 and the external terminal 12b is connected and led out. .

Further, the strip-shaped heating resistor 9 is divided into resistor elements 9a, 9b, 9 by dividing the entire length thereof into approximately six equal parts as in the other embodiment shown in FIG.
c, 9d, 9e, 9f, the resistor element 9a ~ 9f adjacent to each other electrically interposed good electrical conductor 13 made of Ag-Pd paste or the like, respectively arranged in series and arranged alternately It may be configured.

Further, as shown in FIG. 7, the junction between the strip heating resistor 9 and the extraction electrodes 10a and 10b, and the junction between the resistor elements 9a to 9f and the electrical conductor 13 are as shown in FIG.
Are divided into the lower layers 10a ₁ and 10d ₁ and the upper layers 10a ₂ and 10b ₂ , respectively, and the electrically good conductor 13 is divided into the lower layer 13 ₁ and the upper layer 13 _2, and these lower layers 10a ₁ , 10b ₁ and 13 ₁ The resistor 9 is interposed between the upper layers 10a ₂ , 10b ₂ and 13 ₂ . The thickness of the extraction electrodes 10a, 10b and the good electrical conductor 13 is 10 μm.
It is preferable to set the width to -25 μm and the width to 0.5 mm to 10 mm.

Further, a strip-shaped heating resistor 9 is formed by being adhered to the insulating substrate 8.
Lead-free glass such as borosilicate glass and bismuth glass
By coating 14 with a thickness of 10 μm to 100 μm, not only an insulating film is formed, but also generation of creeping discharge on the surface of the resistor 9 can be prevented.

However, if the surge absorber 1 of the present invention is connected to a telephone line or the like, when a surge such as inductive lightning is applied, a discharge is generated in the discharge gap 6 in the discharge type surge absorbing element 2 to generate the surge. Although absorbed, the overcurrent interrupting means 3 does not apply a thermal shock to the thermal destructible portion 11 because the surge applying time is short and the strip heating resistor 9 does not generate much heat. Further, the current is not concentrated on only a part of the strip heating resistor 9 and the strip heating resistor 9 is not burned, and the contact resistance of the joining portion between the strip heating resistor 9 and another member prevents the strip heating resistor 9 from joining. There is no fear of burning out. Furthermore, no creeping discharge is generated on the surface of the strip heating resistor 9,
Reliably absorbs surge.

In addition, when an AC voltage exceeding the rated voltage of the discharge type surge absorbing element 2 is applied to a telephone line for a long time, the arc discharge between the discharge electrodes 4 and 4 is maintained in the discharge type surge absorbing element 2. However, the strip-shaped heating resistor 9 of the overcurrent interruption means 3 suddenly generates heat to apply a thermal shock to the insulating substrate 8 to crush the thermally destructible portion 11 of the insulating substrate 8. As a result, the strip-shaped heating resistor 9 which is a current passage formed on the insulating substrate 8 is cut off, and the overcurrent cutoff means 3 cuts off the excessive voltage that sustains the arc discharge.

[Advantages of the Invention] As described in detail above, according to the surge absorber of the present invention, the strip heating resistor formed by being adhered to the insulating substrate and the strip heating resistor generated by continuous overcurrent conduction are provided. Overcurrent interrupting means consisting of a groove-like heat-destructible portion that crosses a strip-shaped heating resistor formed on the insulating substrate that is crushed by thermal shock, and a discharge electrode that is opposed to the discharge gas with a discharge gap. By connecting in series with the hermetically sealed discharge type surge absorbing element, even if the arc discharge of the discharge type surge absorbing element is in a continuous state during an overvoltage test or a line accident according to various safety standards, The thermal shock from the heating resistor is applied to the heat-destructible portion of the insulating substrate, and the heat-destructible portion is shredded. As a result, the strip-shaped heating resistor, which is the path of the current, is cut off, and the arc discharge in the discharge type surge absorbing element can be cut off, which in turn prevents burnout accidents and is a highly safe surge that conforms to safety standards. It becomes possible to realize an absorber.

Further, in the case where the strip-shaped heating resistor in the surge absorber of the present invention is divided into a plurality of parts, and electrically good conductors are interposed between the adjacent divided resistors, they are alternately arranged in series. A high voltage such as a surge applied to each resistor is divided into lower voltages according to the number of divided resistors. As a result, when a high voltage such as a surge is applied to a single resistor, if an inhomogeneous portion exists in a part of the resistor, current concentrates only in a part of the resistor and the resistor burns out. It is possible to realize a surge absorber with higher safety by eliminating the danger.

Furthermore, the contact area between the strip heating resistor and the electrical good conductor is increased by laminating the joint between the strip heating resistor and the electrical good conductor with the electrical good conductor, the strip heating resistor, and the electrical good conductor. Therefore, the contact resistance is reduced, and there is no fear that the above-mentioned joint will be burned out even by a high voltage such as surge.

Then, by coating the strip-shaped heating resistor adhered to the insulating substrate with deleaded glass, even when a high voltage such as a surge is applied, it is possible to prevent a creeping discharge from occurring on the surface of the resistor, and It is possible to provide a surge absorber with further improved safety.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention, FIG. 2 is an equivalent circuit diagram showing a surge absorber of the present invention, FIG. 3 is a schematic side view showing an embodiment of the present invention, and FIG. FIG. 5 is a schematic sectional view of a discharge type surge absorbing element used in one embodiment of the present invention, FIG. 5 is a schematic rear view showing one embodiment of the present invention, and FIG. 6 is another embodiment of the present invention. FIG. 7 is a schematic rear view, and FIG. 7 is a schematic cross-sectional view of an essential part of the overcurrent interruption means in the present invention. 1 ... Surge absorber, 2 ... Discharge type surge absorber, 3
...... Overcurrent interruption means 4 ...... Discharge electrode, 6 ...... Discharge gap, 8 ...... Insulation substrate, 9
...... Band-shaped heating resistor 11 ...... Thermal destructible part, 13 ...... Electrically good conductor, 14 …… Lead-free glass

Claims (4)

[Scope of utility model registration request] 1. A strip-shaped heating resistor formed on an insulating substrate, and the strip-shaped heating resistor formed on the insulating substrate, which is crushed by thermal shock of the strip-shaped heating resistor generated by continuous application of overcurrent. A discharge electrode, which is connected in series with the above-mentioned strip-shaped heating resistor and an overcurrent interrupting means composed of a groove-like thermally destructible portion that crosses the resistor, is hermetically sealed together with a discharge gas with a discharge electrode. A surge absorber characterized by comprising a discharge type surge absorbing element which is stopped. 2. The strip-shaped heating resistor in the overcurrent cutoff means is divided into a plurality of parts, and a good electrical conductor is interposed between adjacent strip-shaped heating resistors.
The surge absorber according to claim 1, wherein the strip-shaped heat generating resistors and the electrically good conductors are alternately connected in series. 3. The overcurrent interrupting means has a structure in which a plurality of divided strip-shaped heating resistors and a good electrical conductor are joined together in the order of a good electrical conductor, a good heating resistor and a good electrical conductor. The surge absorber according to claim 2, wherein 4. The surge absorber according to claim 1, wherein the strip-shaped heating resistor provided on the insulating substrate is covered with lead-free glass.