JP7700693B2 - Surge protection device - Google Patents

Description

The present invention relates to a surge protection element that is used to protect various devices from surges generated by lightning strikes and other events, and to prevent breakdowns and accidents.

In areas where electronic equipment for communication devices such as telephones, facsimiles, and modems are susceptible to electrical shock from abnormal voltages (surge voltages) such as lightning surges and static electricity, surge protection elements are connected to prevent destruction by thermal damage or fire of the electronic equipment or the printed circuit board on which it is mounted due to abnormal voltages.

Conventionally, known surge protection elements include an element having a discharge gap formed therein and a metal cap pressed into the element and inserted into an insulating tube such as a glass tube, and an element having a discharge electrode sandwiched in parallel between a plate-shaped insulating member having a discharge auxiliary portion such as a carbon trigger.
For example, Patent Document 1 discloses a surge absorber including a microgap element formed by dividing a conductive coating on the surface of an insulating member with a discharge gap interposed therebetween, a pair of main discharge electrodes arranged opposite each other via the microgap element and electrically connected to the conductive coating, and an insulating tube such as a glass tube in which the microgap element is sealed together with a sealing gas with the main discharge electrodes arranged at both ends.
Each of the pair of main discharge electrodes is composed of a cap electrode and a cylindrical terminal electrode.

Patent document 2 also describes a surge protection element that includes an insulating tube such as a glass tube, a pair of sealed electrodes that close the openings at both ends of the insulating tube to seal a discharge control gas inside, a plate-shaped insulating member that is housed inside the insulating tube and has both ends in contact with the pair of sealed electrodes, and a discharge auxiliary part formed of a conductive material in the center of the plate-shaped insulating member.

JP 2007-329040 A JP 2019-153477 A

The above conventional techniques still have the following problems.
Conventional surge protection elements had the disadvantage that when a surge occurs and an arc discharge is formed, the trigger part is located very close to the path of the arc discharge, making the trigger part susceptible to damage by heat emitted from the discharge electrode, etc.
Furthermore, in the sealing step during manufacturing, each component other than the insulating tube must be assembled and then inserted into the insulating tube, which is costly.

The present invention was made in consideration of the above-mentioned problems, and aims to provide a surge protection element that can suppress damage to the trigger part caused by the heat of arc discharge.

The present invention adopts the following configuration to solve the above problem. That is, the surge protection element of the first invention comprises an insulating member, a pair of internal electrode members arranged facing each other with their tip ends in contact with each other on both sides of the axial direction of the insulating member, and an insulating tube to which the base ends of the pair of internal electrode members or sealing electrodes in contact with the base ends are joined at both ends and which seals the insulating member together with a discharge control gas inside, and is characterized in that the insulating member is provided with a discharge auxiliary part made of a conductive material, the tip ends of the pair of internal electrode members have at least a pair of protrusions protruding in directions opposite to each other, and the discharge auxiliary part is provided at a position outside the area connecting the pair of protrusions.

In this surge protection element, the discharge auxiliary part is located outside the area connecting the pair of protrusions, so that an arc discharge occurs between the pair of protrusions, and the discharge auxiliary part, which acts as a trigger, is offset from the path of this arc discharge, which prevents the discharge auxiliary part from being damaged by the arc discharge or heat emitted from the protrusions.

The surge protection element of the second invention is the same as the first invention, and is characterized in that the discharge auxiliary portion is disposed on both sides of a region connecting the pair of projections.
That is, in this surge protection element, the discharge auxiliary parts are arranged on both sides of the region connecting the pair of protrusions, so a more stable trigger discharge is possible compared to a case in which they are arranged only on one side of the region connecting the pair of protrusions. Also, even if one of the discharge auxiliary parts on both sides is damaged, the other discharge auxiliary part can still perform a trigger discharge.

The surge protection element of a third invention is the surge protection element of the first or second invention, characterized in that the pair of protrusions are spaced apart from the insulating member radially outwardly of the insulating tube.
In other words, in this surge protection element, a pair of protrusions are spaced apart from the insulating member radially outward of the insulating tube, so that the arc discharge that occurs between the pair of protrusions occurs away from the insulating member, thereby further suppressing damage to the discharge auxiliary section.

The surge protection element of the fourth invention, in any of the first to third inventions, is characterized in that in the surge protection element described in claim 4, the insulating member is plate-shaped, the pair of protrusions are arranged on both the front and back sides of the insulating member at a distance from the insulating member, and the discharge auxiliary portion is provided on each of the front and back sides of the insulating member.
That is, in this surge protection element, a pair of protrusions is disposed on both the front and back sides of the insulating member, and discharge auxiliary parts are provided on both the front and back sides of the insulating member, so that a more stable trigger discharge can be achieved compared to a case in which the discharge auxiliary parts are provided on only one of the front and back sides of the insulating member. Also, even if one of the discharge auxiliary parts on the front or back side is damaged, trigger discharge can be achieved by the other discharge auxiliary part.

The surge protection element of the fifth invention is characterized in that, in any of the first to fourth inventions, the internal electrode member and the insulating member are each plate-shaped, and both side ends of the internal electrode member and the insulating member are set to a width close to the inner 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, so that the internal electrode member and the insulating member can be prevented from falling over inside the insulating tube. In particular, when the internal electrode member and the insulating member are transferred and inserted into the insulating tube during manufacturing, the internal electrode member and the insulating member can be prevented from falling over inside the insulating tube, so that the internal electrode member and the insulating member can be easily combined. In addition, since the internal electrode member and the insulating member are both plate-shaped, a large space is provided between them and the inner peripheral surface of the insulating tube, and the surge resistance can be improved.

The surge protection element of the sixth invention is characterized in that, in any of the first to fifth inventions, the pair of internal electrode members are plate-shaped having a V-shaped electrode side recess in the center of the tip, the insulating member is plate-shaped with V-shaped insulator side recesses formed at both ends that can engage with the electrode side recesses, and the pair of internal electrode members and the insulating member are combined with each other in a cross shape when viewed in the axial direction.
In other words, in this surge protection element, a pair of internal electrode members and an insulating member are combined with each other in a cross shape when viewed in the axial direction, so that although they are both plate-shaped, their combination results in a three-dimensional structure that allows them to be stably inserted into the insulating tube.
Furthermore, since the insulating member has V-shaped insulator-side recesses at both ends that can be engaged with the V-shaped electrode-side recesses of the internal electrode member, they can be easily combined together in a cross shape when viewed in the axial direction.

According to the present invention, the following effects are obtained.
In other words, in the surge protection element of the present invention, the discharge auxiliary part is provided at a position outside the area connecting the pair of protrusions, so that an arc discharge occurs between the pair of protrusions, and since the discharge auxiliary part, which serves as the trigger part, is offset from the path of this arc discharge, damage to the discharge auxiliary part due to the arc discharge or heat emitted from the protrusions, etc., can be suppressed.

1 is a front view showing an embodiment of a surge protection element according to the present invention; FIG. 2 is a side view showing the surge protection element in the present embodiment. FIG. 2 is a top view showing the surge protection element in the present embodiment.

Below, one embodiment of a surge protection element according to the present invention will be described with reference to Figures 1 to 3. Note that in each of the drawings used in the following description, the scale has been appropriately changed so that each component is recognizable or easily recognizable.

As shown in Figures 1 to 3, the surge protection element 1 of this embodiment includes an insulating member 2, a pair of internal electrode members 3 arranged opposite each other with their tips in contact with each other on both sides of the axial direction of the insulating member 2, and an insulating tube 5 to which sealing electrodes 4 in contact with the base ends 3b of the pair of internal electrode members 3 are joined at both ends and which seals the insulating member 2 together with the discharge control gas inside.

The insulating member 2 is provided with a discharge auxiliary portion 6 made of a conductive material.
The tip portions of the pair of internal electrode members 3 have at least a pair of projections 3a projecting in opposing directions.
In this embodiment, each internal electrode member 3 has two pairs of projections 3a at its tip.

The discharge auxiliary portion 6 is provided at a position outside the region R connecting the pair of projections 3a. In FIG.
Further, the discharge auxiliary portions 6 are disposed on both sides of a region R connecting the pair of projections 3a.
Further, the discharge auxiliary parts 6 are provided on both the front and back surfaces of the insulating member 2 .
These discharge auxiliary parts 6 extend along the axial direction of the insulating tube 5 .

The protrusion 3 a is spaced away from the insulating member 2 toward the outside in the radial direction of the insulating tube 5 .
The internal electrode member 3 and the insulating member 2 are each plate-shaped, and a pair of protrusions 3 a are disposed on both the front and back sides of the insulating member 2 at a distance from 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. The width close to the inner peripheral surface of the insulating tube 5 is preferably such that the internal electrode member 3 and the insulating member 2 can be inserted into the insulating tube 5 and is substantially the same size as the inner peripheral surface of the insulating tube 5 or slightly smaller than the inner peripheral surface.

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 end.
The base end 3b of the internal electrode member 3 is a wide portion formed to be wider than the outer diameter of the sealed electrode 4. As described above, the width of the base end 3b is set to be substantially the same size as the inner peripheral surface of the insulating tube 5 or slightly smaller than the inner peripheral surface.
The insulating member 2 is in the form of a plate having V-shaped insulator-side recesses 2a formed at both ends thereof, which can be engaged with the electrode-side recesses 3c. The insulating member 2 of this embodiment is formed in a substantially X-shape when viewed from the front, as shown in FIG.
As shown in FIG. 3, the pair of internal electrode members 3 and the insulating member 2 are combined with each other in a cross shape when viewed in the axial direction.

The insulating tube 5 is a glass tube, which is made of soft glass such as lead glass or soda-lime glass, and has a cylindrical shape.
The surge protection element 1 of this embodiment also includes a pair of joining glass members 7 that are interposed between the pair of sealing electrodes 4 and both ends of the insulating tube 5 and joined thereto.
The bonding glass member 7 is a so-called bead glass formed into an annular shape, and constitutes a glass layer for fusing the sealed electrode 4 and the insulating tube 5 together.

The sealing electrode 4 is a cylindrical electrode made of a metal, for example, an Fe (iron)-Ni (nickel) alloy, the surface of which is coated with copper oxide.
The sealed electrode 4 is a so-called slug lead, with a lead wire (not shown) welded to the outer end thereof.

The discharge control gas is a sealing gas whose composition is adjusted so that electrical characteristics such as the discharge start voltage are the desired values, and is an inert gas such as He, _Ar , Ne, _Xe , _SF6 , _CO2 , _C3F8 , _C2F6 , _CF4 , _H2 , and mixtures of these gases.
In this embodiment, Ar, _N2 and a mixture thereof are used as the discharge control gas.

Next, a method for manufacturing the surge protection device 1 of this embodiment will be described.
First, one of the pair of sealing electrodes 4 and the bonding glass member 7 are inserted from the upper opening into the upright insulating tube 5. Furthermore, one of the pair of internal electrode members 3 is inserted from the base end 3b side into the upper opening of the insulating tube 5.
Next, the insulating member 2 is inserted, and further the other of the pair of internal electrode members 3 is inserted from the tip end side into the upper opening of the insulating tube 5 .

Then, the bonding glass member 7 is inserted from the upper opening of the insulating tube 5. At this time, the bonding glass member 7 is engaged with the wide base end portion 3b, so that the bonding glass member 7 remains at the upper portion of the insulating tube 5 and does not fall downward. Furthermore, the sealing electrode 4 is inserted into the bonding glass member 7.
In this state, the air inside the insulating tube 5 is replaced with a predetermined discharge control gas, and then both ends of the insulating tube 5 are heated and melted in an atmosphere of discharge control gas, thereby tightly bonding and welding the pair of sealing electrodes 4 and the insulating tube 5 together to form a seal, thereby producing the surge protection element 1.

In this way, in the surge protection element 1 of this embodiment, the discharge auxiliary part 6 is provided at a position outside the region R that connects the pair of protrusions 3a. Therefore, an arc discharge occurs between the pair of protrusions 3a, and the discharge auxiliary part 6 is offset from the path of this arc discharge, which makes it possible to prevent the discharge auxiliary part 6 from being damaged by the arc discharge or heat emitted from the protrusions 3a.

In addition, since the discharge auxiliary parts 6 are arranged on both sides of the region R connecting the pair of projections 3a, a more stable trigger discharge is possible compared to a case in which the discharge auxiliary parts 6 are provided on only one side of the region R connecting the pair of projections 3a. Even if one of the discharge auxiliary parts 6 on both sides is damaged, trigger discharge can be performed by the other discharge auxiliary part 6.
Furthermore, since the pair of protrusions 3a are spaced apart from the insulating member 2 radially outward of the insulating tube 5, the arc discharge generated between the pair of protrusions 3a occurs away from the insulating member 2, thereby further suppressing damage to the discharge auxiliary part 6.

In addition, a pair of protrusions 3a are arranged on both the front and back sides of the insulating member 2 at a distance from the insulating member 2, and the discharge auxiliary parts 6 are provided on both the front and back sides of the insulating member 2, so that a more stable trigger discharge is possible compared to when they are provided on only one of the front and back sides of the insulating member 2. Furthermore, even if one of the discharge auxiliary parts 6 on the front or back side is damaged, the other discharge auxiliary part 6 can still cause a trigger discharge.

In addition, since both sides 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, the internal electrode member 3 and the insulating member 2 can be prevented from falling over inside the insulating tube 5. In particular, when the internal electrode member 3 and the insulating member 2 are transferred and inserted into the insulating tube 5 during manufacturing, the internal electrode member 3 and the insulating member 2 can be prevented from falling over inside the insulating tube 5, and the internal electrode member 3 and the insulating member 2 can be easily combined. In addition, since the internal electrode member 3 and the insulating member 2 are both plate-shaped, a large space is provided between them and the inner peripheral surface of the insulating tube 5, and the surge resistance can be improved.

Furthermore, since the pair of internal electrode members 3 and insulating members 2 are combined with each other in a cross shape when viewed in the axial direction, a three-dimensional structure is obtained by combining them, even though they are plate-shaped, and they can be stably inserted into the insulating tube 5.
In addition, since the insulating member 2 has V-shaped insulator side recesses 2a at both ends which can be engaged with the V-shaped electrode side recesses 3c of the internal electrode member 3, they can be easily combined with each other in a cross shape when viewed in the axial direction.

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.

1...surge protection element, 2...insulating member, 2a...insulating member side recess, 3...internal electrode member, 3a...projection, 3b...base end of internal electrode member, 3c...electrode side recess, 5...insulating tube, 6...discharge auxiliary portion, R...area connecting a pair of projections

Claims (6)

An insulating member;
a pair of internal electrode members disposed on both axial sides of the insulating member such that their tip ends are in contact with each other and opposed to each other;
an insulating tube to which base ends of the pair of internal electrode members or sealing electrodes in contact with the base ends are joined at both ends and which seals the insulating members together with a discharge control gas therein;
The insulating member is provided with a discharge auxiliary portion made of a conductive material,
the tip portions of the pair of internal electrode members have at least a pair of projections projecting in directions opposed to each other,
A surge protection element, characterized in that the discharge auxiliary portion is provided at a position outside a region connecting the pair of projections. 2. The surge protection device according to claim 1,
A surge protection element, characterized in that the discharge auxiliary portion is disposed on both sides of a region connecting the pair of projections. 3. The surge protection device according to claim 1,
A surge protection element, characterized in that the pair of protrusions are spaced apart from the insulating member radially outwardly of the insulating tube. 4. The surge protection device according to claim 3,
The insulating member is plate-shaped,
the pair of protrusions are disposed on both the front and back sides of the insulating member at a distance from the insulating member,
A surge protection element, characterized in that the discharge auxiliary portion is provided on each of the front and back surfaces of the insulating member. The surge protection device according to any one of claims 1 to 4,
The internal electrode member and the insulating member are each plate-shaped,
A surge protection element, characterized in that both side portions of the internal electrode member and the insulating member are set to a width close to an inner peripheral surface of the insulating tube. The surge protection device according to any one of claims 1 to 5,
The pair of internal electrode members are plate-shaped with a V-shaped electrode-side recess at the center of the tip portion,
the insulating member is in the form of a plate having V-shaped insulator-side recesses at both ends thereof that can be engaged with the electrode-side recesses,
A surge protection element, characterized in that the pair of internal electrode members and the insulating member are combined with each other in a cross shape when viewed in the axial direction.

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