Surge protection element

Abstract

To provide a surge protective element capable of suppressing damage to a trigger portion due to heat from an arc discharge.SOLUTION: A surge protective element includes an insulating member 2, a pair of inner electrode members 3 arranged opposing each other with their end parts in contact on both sides in the axial direction of the insulating member, and an insulating tube 5 to both ends of which a base end portion 3b or a sealing electrode 4 in contact with the base end portion of a pair of inner electrode members is bonded and that seals the insulating member with a discharge control gas inside. The insulating member is provided with a discharge auxiliary portion 6 formed of a conductive material. A tip end portion of the pair of inner electrode members has at least a pair of protruding portions 3a protruding in opposite directions to each other. A discharge auxiliary portion is provided in a position outside of an area R connecting the pair of protrusions.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a surge protection element used to protect various devices from surges generated by lightning strikes or the like and prevent failures and accidents in advance.

Background Art

[0002] In parts where electronic devices for communication devices such as telephones, facsimiles, and modems are connected to communication lines, power lines, antennas, or CRT drive circuits, etc., which are susceptible to electric shock by abnormal voltages (surge voltages) such as lightning surges and static electricity, surge protection elements are connected to prevent destruction due to thermal damage or ignition of the electronic devices or the printed circuit boards on which these devices are mounted by the abnormal voltages.

[0003] Conventionally, as surge protection elements, those in which a metal cap is press-fitted into an element forming a discharge gap and inserted into an insulating tube such as a glass tube, or those in which discharge electrodes are sandwiched in parallel between plate-shaped insulating members forming a discharge assisting part such as a carbon trigger are known. For example, as shown in Patent Document 1, a micro-gap element in which a conductive film is divided and formed on the surface of an insulating member via a discharge gap, a pair of main discharge electrodes arranged opposite each other via the micro-gap element and electrically connected to the conductive film, and an insulating tube such as a glass tube that seals the micro-gap element together with a sealing gas inside with the main discharge electrodes arranged at both ends are provided. A surge absorber is described. The pair of main discharge electrodes are each composed of a cap electrode and a columnar terminal electrode.

[0004] Also, Patent Document 2 describes a surge protection element including an insulating tube such as a glass tube, a pair of sealing electrodes that close the both ends of the insulating tube and seal a discharge control gas inside, a plate-shaped insulating member housed inside the insulating tube and having both ends in contact with the pair of sealing electrodes, and a discharge assisting part formed of a conductive material at the center of the plate-shaped insulating member.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] The following problems remain in the above conventional technology. In a conventional surge protection element, when a surge enters and an arc discharge is formed, since the trigger portion is very close to the path of the arc discharge, there is a disadvantage that the trigger portion is easily damaged by heat or the like emitted from the discharge electrode. In addition, in the encapsulation process during manufacturing, after combining each member other than the insulating tube, it has to be poured into the insulating tube, which is costly.

[0007] The present invention has been made in view of the above problems, and an object thereof is to provide a surge protection element capable of suppressing damage to a trigger portion due to heat of arc discharge.

Means for Solving the Problems

[0008] The present invention adopts the following configuration to solve the above problems. That is, the surge protection element of the first invention includes an insulating member, a pair of internal electrode members whose tip portions are in contact with each other and arranged opposite to each other on both axial sides of the insulating member, and a sealing electrode that is joined to both ends of the base end portion of the pair of internal electrode members or in contact with the base end portion, and an insulating tube that seals the insulating member together with a discharge control gas inside. A discharge assisting portion formed of a conductive material is provided on the insulating member. The tip portions of the pair of internal electrode members have at least a pair of protruding portions protruding in a direction opposite to each other, and the discharge assisting portion is provided at a position deviated from a region connecting the pair of protruding portions.

[0009] In this surge protection element, since the discharge assisting portion is provided at a position deviated from the region connecting the pair of protrusions, arc discharge occurs between the pair of protrusions, and the discharge assisting portion serving as the trigger portion is displaced from the path of this arc discharge, thereby suppressing damage to the discharge assisting portion caused by the arc discharge, heat released from the protrusions, or the like.

[0010] The surge protection element of the second invention is characterized in that, in the first invention, the discharge assisting portion is arranged on both sides of the region connecting the pair of protrusions. That is, in this surge protection element, since the discharge assisting portion is arranged on both sides of the region connecting the pair of protrusions, stable trigger discharge becomes possible as compared with the case where it is provided only on one side of the region connecting the pair of protrusions. Further, even if one of the discharge assisting portions on both sides is damaged, trigger discharge can be performed by the other discharge assisting portion.

[0011] The surge protection element of the third invention is characterized in that, in the first or second invention, the pair of protrusions are spaced apart radially outward from the insulating member toward the outer side of the insulating tube. That is, in this surge protection element, since the pair of protrusions are spaced apart radially outward from the insulating member toward the outer side of the insulating tube, the arc discharge occurring between the pair of protrusions occurs at a distance from the insulating member, and damage to the discharge assisting portion can be further suppressed.

[0012] The surge protection element of the fourth invention is characterized in that, in any one of the first to third inventions, in the surge protection element according to claim 4, the insulating member is plate-shaped, the pair of protrusions are spaced apart from the insulating member on both the front surface side and the back surface side of the insulating member, and the discharge assisting portions are respectively provided on the front and back surfaces of the insulating member. That is, in this surge protection element, a pair of protrusions are arranged on both the front surface side and the back surface side of the insulating member, and the discharge assisting portions are provided on the front and back surfaces of the insulating member respectively. Therefore, stable trigger discharge becomes possible as compared with the case where it is provided only on one of the front and back surfaces of the insulating member. Further, even if one of the discharge assisting portions on the front and back surfaces is damaged, trigger discharge can be performed by the other discharge assisting portion.

[0013] The surge protection element of the fifth invention is characterized in that, in any one of the first to fourth inventions, the internal electrode member and the insulating member are each plate-shaped, and both side portions of the internal electrode member and the insulating member are set to a width close to the inner peripheral surface of the insulating tube. That is, in this surge protection element, both side portions of the internal electrode member and the insulating member are set to a width close to the inner peripheral surface of the insulating tube. Therefore, it is possible to prevent the internal electrode member and the insulating member from falling down inside the insulating tube. In particular, when the internal electrode member and the insulating member are poured and inserted into the insulating tube during manufacturing, it is possible to prevent them from falling down inside the insulating tube, and the internal electrode member and the insulating member can be easily combined. Further, since the internal electrode member and the insulating member are each plate-shaped, a large amount of space can be obtained between them and the inner peripheral surface of the insulating tube, and the surge withstand voltage can be improved.

[0014] The surge protection element of the sixth invention is characterized in that, in any one of the first to fifth inventions, the pair of internal electrode members are plate-shaped with a V-shaped electrode-side concave portion at the center of the tip portion, the insulating member is plate-shaped with V-shaped insulator-side concave portions that can be locked to the electrode-side concave portion formed at both ends, and the pair of internal electrode members and the insulating member are combined in a cross shape when viewed in the axial direction. That is, in this surge protection element, the pair of internal electrode members and the insulating member are combined in a cross shape when viewed in the axial direction. Therefore, a three-dimensional structure is obtained by combining them while being plate-shaped, and they can be stably poured into the insulating tube. In addition, since the insulating member is formed with V-shaped insulator-side concave portions at both ends that can be locked to the V-shaped electrode-side concave portions of the internal electrode member, they can be easily combined in a cross shape when viewed in the axial direction.

Advantages of the Invention

[0015] According to the present invention, the following effects can be achieved. That is, according to the surge protection element of the present invention, since the discharge assisting portion is provided at a position deviated from the region connecting the pair of protrusions, arc discharge occurs between the pair of protrusions, and the discharge assisting portion serving as the trigger portion is displaced from the path of this arc discharge, it is possible to suppress damage to the discharge assisting portion caused by arc discharge or heat released from the protrusions.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0017] Hereinafter, an embodiment of a surge protection element according to the present invention will be described with reference to FIGS. 1 to 3. In each of the drawings used in the following description, the scale is appropriately changed in order to make each member recognizable or easily recognizable.

[0018] As shown in FIGS. 1 to 3, the surge protection element 1 of this embodiment includes an insulating member 2, a pair of internal electrode members 3 whose tip portions are in contact with and opposed to each other on both sides in the axial direction of the insulating member 2, and a sealing electrode 4 in contact with the base end portions 3b of the pair of internal electrode members 3 is joined to both ends and an insulating tube 5 that seals the insulating member 2 together with a discharge control gas inside.

[0019] The insulating member 2 is provided with a discharge assisting portion 6 formed of a conductive material. The tip portions of the pair of internal electrode members 3 each have at least a pair of protruding portions 3a protruding in a direction facing each other. In this embodiment, two pairs of protruding portions 3a are provided at the tip portions of the respective internal electrode members 3.

[0020] The discharge assisting portion 6 is provided at a position deviated from the region R connecting the pair of protruding portions 3a. In FIG. 1, the region R is hatched. Further, the discharge assisting portion 6 is arranged on both sides of the region R connecting the pair of protruding portions 3a. Furthermore, the discharge assisting portions 6 are respectively provided on the front and back surfaces of the insulating member 2. These discharge assisting portions 6 extend along the axial direction of the insulating tube 5.

[0021] The protruding portion 3a is spaced apart from the insulating member 2 toward the outer side in the radial direction of the insulating tube 5. The internal electrode member 3 and the insulating member 2 are each plate-shaped, and the pair of protruding portions 3a are spaced apart from the insulating member 2 on both the front surface side and the back surface side of the insulating member 2. Both side portions of the internal electrode member 3 and the insulating member 2 are set to a width close to the inner peripheral surface of the insulating tube 5. As the proximity width, it is preferable that the internal electrode member 3 and the insulating member 2 can be inserted into the insulating tube 5 and are substantially the same size as or slightly smaller than the inner peripheral surface of the insulating tube 5.

[0022] The pair of internal electrode members 3 are plate-shaped and have a V-shaped electrode-side recess 3c at the center of the tip portion. The base end portion 3b of the internal electrode member 3 is a wide portion formed wider than the outer diameter of the sealing electrode 4. As described above, the width of the base end portion 3b is set to be substantially the same size as or slightly smaller than the inner peripheral surface of the insulating tube 5. The insulating member 2 is a plate-shaped member having V-shaped insulator-side recesses 2a that can be locked to the electrode-side recesses 3c at both ends. In addition, as shown in FIG. 1, the insulating member 2 of the present embodiment is formed in a substantially X shape when viewed from the front. Then, as shown in FIG. 3, the pair of internal electrode members 3 and the insulating member 2 are combined in a cross shape when viewed in the axial direction.

[0023] The insulating tube 5 is a glass tube, which is made of a soft glass such as lead glass or soda lime glass, and has a cylindrical shape. In addition, the surge protection element 1 of the present embodiment includes a pair of bonding glass members 7 that are interposed between the pair of sealing electrodes 4 and both ends of the insulating tube 5 and are joined to them. The bonding glass member 7 is a so-called annularly formed bead glass, and constitutes a glass layer for welding the sealing electrode 4 and the insulating tube 5.

[0024] The sealing electrode 4 is an electrode formed of a metal in which the surface of, for example, an Fe (iron)-Ni (nickel) alloy is coated with copper oxide, and has a cylindrical shape. In addition, the sealing electrode 4 is a so-called slag lead in which a lead wire (not shown) is welded to the outer end.

[0025] The discharge control gas is a sealing gas whose composition and the like are adjusted so that electrical characteristics such as the discharge start voltage become desired values, and is an inert gas such as He, Ar, Ne, Xe, SF6, CO2, C3F8, C2F6, CF4, H2, and a mixed gas thereof. In the present embodiment, Ar, N2, and a mixed gas thereof are employed as the discharge control gas.

[0026] Next, a method for manufacturing the surge protection element 1 of the present embodiment will be described. First, one of the pair of sealing electrodes 4 and the bonding glass member 7 are introduced into the erected insulating tube 5 through the upper opening. Further, one of the pair of internal electrode members 3 is introduced into the upper opening of the insulating tube 5 from the base end portion 3b side. Next, the insulating member 2 is inserted, and the other of the pair of internal electrode members 3 is inserted from the tip side through the upper opening of the insulating tube 5.

[0027] Then, the bonding glass member 7 is inserted through the upper opening of the insulating tube 5. At this time, the bonding glass member 7 is locked to the wide base end portion 3b, so that the bonding glass member 7 stays at the upper part of the insulating tube 5 and does not fall downward. Further, the sealing electrode 4 is inserted into the bonding glass member 7. In this state, after replacing the air in the insulating tube 5 with a predetermined discharge control gas, both ends of the insulating tube 5 are heated and melted in the atmosphere of the discharge control gas, so that the pair of sealing electrodes 4 and the insulating tube 5 are brought into close contact and welded to perform sealing, and the surge protection element 1 is manufactured.

[0028] Thus, in the surge protection element 1 of the present embodiment, since the discharge assisting portion 6 is provided at a position deviated from the region R connecting the pair of protrusions 3a, arc discharge occurs between the pair of protrusions 3a, and the discharge assisting portion 6 is displaced from the path of this arc discharge, it is possible to suppress damage to the discharge assisting portion 6 due to arc discharge or heat released from the protrusions 3a.

[0029] Further, since the discharge assisting portion 6 is arranged on both sides of the region R connecting the pair of protrusions 3a, stable trigger discharge becomes possible as compared with the case where it is provided only on one side of the region R connecting the pair of protrusions 3a. Further, even if one of the discharge assisting portions 6 on both sides is damaged, trigger discharge can be performed by the other discharge assisting portion 6. Furthermore, since the pair of protrusions 3a are separated from the insulating member 2 outward in the radial direction of the insulating tube 5, the arc discharge generated between the pair of protrusions 3a occurs away from the insulating member 2, and damage to the discharge assisting portion 6 can be further suppressed.

[0030] In addition, a pair of protrusions 3a are arranged spaced apart from the insulating member 2 on both the front surface side and the back surface side of the insulating member 2, and the discharge assisting portions 6 are provided on the front and back surfaces of the insulating member 2, respectively. Therefore, stable trigger discharge becomes possible as compared with the case where they are provided only on one of the front and back surfaces of the insulating member 2. Further, even if one of the discharge assisting portions 6 on the front and back surfaces is damaged, trigger discharge can be performed by the other discharge assisting portion 6.

[0031] In addition, both side portions of the internal electrode member 3 and the insulating member 2 are set to a width close to the inner peripheral surface of the insulating tube 5, so that it is possible to prevent the internal electrode member 3 and the insulating member 2 from falling down inside the insulating tube 5. In particular, when the internal electrode member 3 and the insulating member 2 are poured and inserted into the insulating tube 5 during manufacturing, it is possible to prevent them from falling down inside the insulating tube 5, and the internal electrode member 3 and the insulating member 2 can be easily combined. Further, since the internal electrode member 3 and the insulating member 2 are plate-shaped with respect to each other, a large amount of space is obtained between them and the inner peripheral surface of the insulating tube 5, and the surge withstand voltage can be improved.

[0032] Furthermore, since the pair of internal electrode members 3 and the insulating member 2 are combined in a cross shape when viewed in the axial direction, a three-dimensional structure is obtained by combining them while being plate-shaped with respect to each other, and they can be stably poured into the insulating tube 5. In addition, since the insulating member 2 is formed with V-shaped insulator-side concave portions 2a at both ends that can be locked to the V-shaped electrode-side concave portions 3c of the internal electrode member 3, they can be easily combined in a cross shape when viewed in the axial direction.

[0033] Note that the technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

Explanation of Reference Numerals

[0034] 1... Surge protection element, 2... Insulating member, 2a... Insulator-side concave portion, 3... Internal electrode member, 3a... Protrusion, 3b... Base end portion of internal electrode member, 3c... Electrode-side concave portion, 5... Insulating tube, 6... Discharge assisting portion, R... Region connecting a pair of protrusions

Claims

1. An insulating member, A pair of internal electrode members whose tip portions are in contact with and opposed to each other on both axial sides of the insulating member, An insulating tube in which a sealing electrode in contact with the base end portions of the pair of internal electrode members or the base end portions is joined to both ends, and the insulating member is sealed together with a discharge control gas inside, A discharge assisting portion formed of a conductive material is provided on the insulating member, The tip portions of the pair of internal electrode members have at least a pair of protruding portions protruding in directions opposite to each other, The surge protection element is characterized in that the discharge assisting portion is provided at a position deviated from a region connecting the pair of protruding portions.

2. In the surge protection element according to claim 1, The surge protection element is characterized in that the discharge assisting portion is arranged on both sides of a region connecting the pair of protruding portions.

3. In the surge protection element according to claim 1 or 2, The surge protection element is characterized in that the pair of protruding portions are spaced apart from the insulating member radially outward in the radius direction of the insulating tube.

4. In the surge protection element according to claim 3, The insulating member is plate-shaped, The pair of protruding portions are arranged spaced apart from the insulating member on both the front surface side and the back surface side of the insulating member, The surge protection element is characterized in that the discharge assisting portions are provided on the front and back surfaces of the insulating member, respectively.

5. In the surge protection element according to any one of claims 1 to 4, The internal electrode member and the insulating member are each plate-shaped, The surge protection element is characterized in that both side portions of the internal electrode member and the insulating member are set to a width close to the inner peripheral surface of the insulating tube.

6. In the surge protection element according to any one of claims 1 to 5, The pair of internal electrode members are plate-shaped and have a V-shaped electrode-side recess at the center of the tip portion, The insulating member is plate-shaped and has V-shaped insulator-side recesses formed at both ends that can be locked to the electrode-side recesses, The surge protection element is characterized in that the pair of internal electrode members and the insulating member are combined in a cross shape when viewed in the axial direction.

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