Thermal tripping structure and surge protector

Abstract

The utility model provides a thermal tripping structure and a surge protector. The thermal tripping structure comprises an on-chip electrode arranged on an MOV chip; the extraction electrode is welded on the chip upper electrode; the chip upper electrode is provided with a welding boss embedded with the extraction electrode, and a welding convex strip protrudes from the welding boss; the front end plane of the extraction electrode is opened to form a welding opening which is embedded into the welding boss. An existing thermal tripping structure is improved, the front end plane of the extraction electrode is directly opened to form a welding opening, on one hand, a welding line of a welding boss is effectively lengthened, so that firmness is enhanced, and large pulse current is coped with; and on the other hand, the front end plane of the extraction electrode is directly pressed downwards, so that the welding opening and the welding boss are welded in an embedded manner, and the separation distance between the extraction electrode and the welding boss after thermal separation can be ensured and an arc discharge fault can be avoided by depending on the material characteristics of the extraction electrode, providing power for thermal separation and performing tripping through natural reset of the horizontal plate surface.

Description

Technical Field

[0001] The invention relates to the technical field of lightning protection equipment, and in particular to a thermal trip structure and a surge protector. Background Art

[0002] The alloy welding point of the existing SPD (surge protector) has a small welding area. Although it is equipped with a concave groove and a tin-through hole, it can be welded. However, due to the small contact area, under the impact of a large current pulse of tens or hundreds of KA, the electric field force will tear this point apart, losing the protection function, thus causing backup electrical accidents. See Figure 1 , including lead-out electrode A, tin-through hole B, welding groove C, groove upper fold D, chip electrode E, chip F, welding surface G, and welding boss H.

[0003] In order to form a welding groove, the front end of the lead-out electrode must be folded upward. Therefore, when the lead-out electrode is thermally detached, the insertion of the shielding plate raises the upper folding point and presses against the outer shell, resulting in insufficient detachment distance, which in turn poses a safety hazard of arcing accidents.

[0004] At the same time, thermal separation relies on the chip heat to soften or melt the alloy welding point, so that the lead electrode is separated from the chip under the action of the spring, and the welding area between the lead electrode and the electrode on the chip is small. Therefore, when a fault occurs, due to the slow heat conduction of the chip (large thermal resistance), it is easy to cause delayed separation or a breakdown short circuit accident. Summary of the invention

[0005] The invention provides a thermal trip structure and a surge protector, which solve the technical problems that the thermal trip structure in the existing surge protector has a short disengagement distance, a small lead-out electrode welding area, and potential safety hazards such as arcing, delayed disengagement or breakdown short circuit, and poor safety.

[0006] In order to solve the above technical problems, the present invention provides a thermal trip structure, comprising:

[0007] An on-chip electrode disposed on the MOV chip;

[0008] and, a lead-out electrode welded to the electrode on the chip;

[0009] The chip electrode is provided with a welding boss which is engaged with the lead-out electrode, and a welding convex strip arranged on the top of the welding boss;

[0010] The front end plane opening of the lead-out electrode forms a welding opening, and the welding opening is embedded in the welding convex strip;

[0011] The front end plane of the lead-out electrode is pressed downward, and after the welding opening and the welding convex strip are engaged, they are fixed by temperature alloy welding to form a release point;

[0012] When the temperature generated by the degradation of the MOV chip is too high, the lead-out electrode is disconnected from the welding connection with the electrode on the chip, so that the welding joint is released from the pressing and resets itself upward.

[0013] This basic solution is improved based on the existing thermal release structure. An opening is directly made on the front end plane of the lead-out electrode to form a fork-shaped welding joint. On the one hand, the length of the welding line with the welding boss is effectively increased to enhance the firmness and cope with large pulse currents. On the other hand, the front end plane of the lead-out electrode is pressed downward to make the welding joint and the welding boss welded together. Relying on the material properties of the lead-out electrode, the power for thermal release is provided, and the release is executed through the natural resetting of the plane. This can ensure the release distance between the lead-out electrode and the welding boss after thermal release occurs, avoid arcing failures, and thus improve the reliability and safety of the device.

[0014] In a further embodiment, the top surface of the welding boss is low in the front and high in the back to form an inclined surface, and the welding port is welded on the inclined surface;

[0015] The inclination angle of the inclined surface is the same as the welding angle formed when the lead-out electrode is pressed downward; after the welding opening on the front end plane of the lead-out electrode is pressed downward, it is attached to the inclined surface and fixed by temperature alloy welding;

[0016] When the temperature generated by the degradation of the MOV chip is too high, the temperature alloy melts, and the lead electrode naturally rises upward under the elastic potential energy generated by the plane downward pressure, disconnecting the welding connection with the electrode on the chip; so that the welding joint is free from the pressure and resets itself upward, causing the external circuit connected to the lead electrode to be in an open circuit state.

[0017] In a further embodiment, the welding convex strip is arranged in the middle of the inclined surface, the top plane of which is parallel to the electrode on the chip, and the welding ports are nested on both sides thereof;

[0018] The front end plane of the lead-out electrode is pressed downward so that the welding port is aligned with the welding convex strip and embedded, and the welding port is close to the inclined surface, and then fixed by temperature alloy welding to form a release point at the welding connection point.

[0019] This solution is based on the horizontal fork-shaped welding joint at the front end of the lead-out electrode and the serrated or wavy design of the outer edge of the fork-shaped welding joint. The top surface of the welding boss is set to an inclined inclined surface to conform to the natural downward bending inclination of the lead-out electrode during welding, and the fork-shaped welding joint is naturally embedded on both sides of the welding convex strip, thereby ensuring sufficient welding length and area. Since the contact area becomes larger, its thermal resistance becomes smaller. In the event of a fault, the heat of the MOV chip can reach the disengagement point faster, and the tripping is safer. In addition, due to the sufficient welding length and area, the tolerance to strong current pulses is also enhanced.

[0020] In a further embodiment, the lower portion of the extraction electrode is a vertical portion and the upper portion is a horizontal portion;

[0021] The vertical portion extends downward and protrudes out to connect with an external circuit;

[0022] The horizontal portion is a horizontal plate surface, the rear end of which is bent and connected to the vertical portion, and the front end of which is provided with the welding port; the welding port opens to the rear end to form a fork-shaped welding port;

[0023] The horizontal plate surface is pressed downward so that the fork-shaped welding opening is nested on the welding boss and fixed by temperature alloy welding, thereby forming a tripping point at the welding connection point.

[0024] In a further embodiment, the opening of the fork-shaped welding port is a rectangular fitting surface that fits the welding convex strip, and the inner diameter of the rectangular fitting surface is greater than the outer diameter of the welding convex strip.

[0025] In a further embodiment, the outer edges on both sides of the fork-shaped welding opening are recessed inward to form a sawtooth structure or a wavy structure; the starting and ending positions of the sawtooth structure or the wavy structure are flush with the starting and ending positions of the middle opening of the fork-shaped welding opening.

[0026] In this solution, a fork-shaped welding port is provided with an inward opening at the front end. On the one hand, the opening is nested and welded with the convex strip to expand the inclined surface; on the other hand, a sawtooth structure or a wavy structure is provided on the outer edge of the fork-shaped welding port to effectively increase the length of the welding line and enhance the welding firmness. The above two measures can improve the heat conduction rate of the MOV chip, resist large current shocks, and ensure the safety of the device.

[0027] In a further embodiment, the height of the side wall of the welding protrusion is equal to or greater than the plate thickness of the fork-shaped welding opening. Specifically, after the fork-shaped welding opening is welded on the welding protrusion, the welding protrusion protrudes from the welding plane or is flush with the welding plane.

[0028] This solution ensures the stability of welding by setting the height of the welding convex strip relative to the inclined surface so that its height is equal to or greater than the plane after welding of the fork-shaped welding joint, and by exceeding the welding plane (that is, the plane formed after welding of the fork-shaped welding joint).

[0029] The present invention also provides a surge protector, comprising the above-mentioned thermal trip structure, and also comprising a shell as a fixed structure, wherein an MOV chip is arranged in the shell; the thermal trip structure comprises an on-chip electrode arranged on the MOV chip, and a lead-out electrode welded on the on-chip electrode; a welding boss engaged with the lead-out electrode is provided on the on-chip electrode; a front end plane opening of the lead-out electrode forms a welding port, and the welding port is embedded in the welding boss.

[0030] The structural surge protector of the present invention applies a new thermal tripping structure, which makes the SPD product more reliable and safer while ensuring the original cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a diagram of the existing thermal tripping structure provided by an embodiment of the present invention;

[0032] Figure 2 is a welding schematic diagram of a thermal release structure provided by an embodiment of the present invention;

[0033] Figure 3 The embodiment of the present invention provides Figure 2 The three-dimensional structure diagram of the lead-out electrode;

[0034] Figure 4 is a three-dimensional structural diagram of electrodes on another chip provided by an embodiment of the present invention;

[0035] Figure 5 is a three-dimensional structural diagram of electrodes on another chip provided by an embodiment of the present invention;

[0036] Figure 6 It is a three-dimensional structural diagram of another electrode on a chip provided by an embodiment of the present invention.

[0037] Among them: MOV chip 1, chip upper electrode 2, lead electrode 3, welding boss 4; chip lower electrode 5; welding port 31, vertical part 32, horizontal part 33; inclined surface 41, welding convex strip 42. DETAILED DESCRIPTION

[0038] The following specifically illustrates the implementation mode of the present invention in conjunction with the accompanying drawings. The embodiments are provided for illustrative purposes only and are not to be construed as limitations of the present invention. The accompanying drawings are provided for reference and illustration only and do not constitute limitations on the scope of patent protection of the present invention, because many changes may be made to the present invention without departing from the spirit and scope of the present invention.

[0039] Example 1

[0040] An embodiment of the present invention provides a thermal trip structure, such as Figure 2~Figure 6 As shown, in this embodiment, it includes:

[0041] An on-chip electrode 2 disposed on the MOV chip 1;

[0042] and, an extraction electrode 3 welded on the electrode 2 on the chip;

[0043] The chip electrode 2 is provided with a welding boss 4 which is engaged with the lead-out electrode 3, and a welding convex strip 42 which is provided on the top of the welding boss 4;

[0044] The front end plane opening of the lead electrode 3 forms a welding opening 31, and the welding opening 31 is embedded in the welding convex strip 42;

[0045] The front end plane of the lead-out electrode 3 is pressed downward, and the welding opening 31 is engaged with the welding convex strip 42 and then fixed by temperature alloy welding to form a release point;

[0046] When the temperature generated by the degradation of the MOV chip 1 is too high, the lead-out electrode 3 is disconnected from the welding connection with the electrode 2 on the chip, so that the welding port 31 is released from the pressing and resets itself upward.

[0047] In this embodiment, the temperature alloy is designed as the heat-shedding structure, so that the heat-shedding structure can be formed with fixed support points and functional characteristics of overheating melting protection, so that the safety factor of the product is further improved.

[0048] In this embodiment, the top surface of the welding boss 4 is low in the front and high in the back to form an inclined surface, and the welding port 31 is welded on the inclined surface;

[0049] The inclination angle of the inclined surface is the same as the welding angle formed when the lead-out electrode 3 is pressed downward; after the welding opening 31 on the front end plane of the lead-out electrode 3 is pressed downward, it is attached to the inclined surface and fixed by temperature alloy welding;

[0050] When the temperature generated by the degradation of the MOV chip 1 is too high, the temperature alloy melts, and the lead electrode 3 naturally rises upward under the elastic potential energy generated by the plane downward pressure, disconnecting the welding connection with the electrode 2 on the chip; so that the welding port 31 is freed from the pressure and resets itself upward, causing the external circuit connected to the lead electrode 3 to be in an open circuit state.

[0051] In this embodiment, the welding convex strip 42 is arranged in the middle of the inclined surface 41, the top plane of which is parallel to the electrode 2 on the chip, and the fork-shaped welding openings 31 are embedded on both sides thereof;

[0052] The front end plane of the lead electrode 3 is pressed downward so that the welding port 31 is aligned with the welding convex strip 42 and embedded. At the same time, the welding port 31 is close to the inclined surface 41 and then fixed by temperature alloy welding to form a release point at the welding connection point.

[0053] In this embodiment, the height of the side wall of the welding protrusion 42 is equal to or greater than the plate thickness of the fork-shaped welding opening 31. Specifically, after the fork-shaped welding opening 31 is welded on the welding protrusion 42, the welding protrusion 42 protrudes from the welding plane or is flush with the welding plane.

[0054] In this embodiment, the top corner of the welding protrusion 42 can be set to a smooth curved surface structure according to needs, and the auxiliary welding opening 31 is aligned and embedded in the welding protrusion 42.

[0055] In this embodiment, the height of the welding protrusion 42 relative to the inclined surface is set to be equal to or greater than the plane of the fork-shaped welding joint 31 after welding, and the stability of the welding is ensured by exceeding the plane of the welding area (i.e., the plane of the fork-shaped welding joint 31 after welding).

[0056] In this embodiment, based on the horizontal fork-shaped welding opening 31 at the front end of the lead-out electrode 3 and the serrated or wavy outer edge design of the fork-shaped welding opening 31, the top surface of the welding boss 4 is set to be an inclined inclined surface 41, so that it conforms to the inclination of the natural downward bending of the lead-out electrode 3 during welding, and the fork-shaped welding opening 31 is naturally embedded on both sides of the welding protrusion 42, thereby ensuring sufficient welding length and area. Since the contact area becomes larger, its thermal resistance becomes smaller. In the event of a fault, the heat of the MOV chip 1 can reach the separation point faster, and the tripping is safer. In addition, due to the sufficient welding length and area, the tolerance to strong current pulses is also enhanced.

[0057] In this embodiment, the lower portion of the extraction electrode 3 is a vertical portion 32, and the upper portion is a horizontal portion 33;

[0058] The vertical portion 32 extends downward to connect with an external circuit;

[0059] The horizontal portion 33 is a horizontal plate surface, the rear end of which is bent and connected to the vertical portion 32, and the front end of which is provided with the welding opening 31; the welding opening 31 opens to the rear end to form a fork-shaped welding opening 31;

[0060] The horizontal plate surface is pressed downwards so that the fork-shaped welding opening 31 is nested on the welding boss 4 and fixed by temperature alloy welding, thereby forming a release point at the welding connection point.

[0061] In this embodiment, the opening of the fork-shaped welding opening 31 is a rectangular fitting surface that fits the welding protrusion 42 , and the inner diameter of the rectangular fitting surface is greater than the outer diameter of the welding protrusion 42 .

[0062] In this embodiment, the outer edges of both sides of the fork-shaped welding opening 31 are recessed inward to form a sawtooth structure or a wavy structure (such as Figure 3 The starting and ending positions of the sawtooth structure or the wavy structure are flush with the starting and ending positions of the middle opening of the fork-shaped welding opening 31.

[0063] In this embodiment, a fork-shaped welding opening 31 is provided with an inward opening at the front end. On the one hand, the opening is nested and welded with the convex strip to expand the inclined surface 41; on the other hand, the sawtooth structure or the wavy structure provided on the outer edge of the fork-shaped welding opening 31 effectively increases the length of the welding line and enhances the welding firmness. The above two measures can improve the heat conduction rate of the MOV chip 1, resist the impact of large current, and ensure the safety of the device.

[0064] The embodiment of the present invention is improved based on the existing thermal release structure. An opening is directly made on the front end plane of the lead-out electrode 3 to form a fork-shaped welding opening 31. On the one hand, the length of the welding line with the welding boss 4 is effectively increased to enhance the firmness and cope with large pulse currents. On the other hand, the front end plane of the lead-out electrode 3 is pressed downward to make the welding opening 31 and the welding boss 4 engage and weld. Relying on the material properties of the lead-out electrode 3, the power of thermal release is provided, and the release is performed by the natural resetting of the plane. The release distance between the lead-out electrode 3 and the welding boss 4 after thermal release can be guaranteed to avoid arcing failures, thereby improving the reliability and safety of the device.

[0065] Example 2

[0066] The present invention also provides a surge protector, see Figure 2 , including the thermal trip structure provided in the above-mentioned embodiment 1, and also including a shell as a fixed structure. The present invention also provides a surge protector, including the above-mentioned thermal trip structure, and also including a shell as a fixed structure, wherein an MOV chip 1 is arranged in the shell; the thermal trip structure includes an on-chip electrode 2 arranged on the MOV chip 1, and a lead-out electrode 3 welded on the on-chip electrode 2; a welding boss 4 embedded with the lead-out electrode 3 is provided on the on-chip electrode 2; the front end plane opening of the lead-out electrode 3 forms a welding port 31, and the welding port 31 is embedded in the welding boss 4.

[0067] In this embodiment, the present invention further comprises a chip bottom electrode 5 , the chip bottom electrode 5 is electrically connected to the MOV chip 1 , and the MOV chip 1 is connected to an external circuit via the chip bottom electrode 5 .

[0068] The on-chip electrodes 2 in this embodiment include but are not limited to Figure 4 , Attachment Figure 5 , Attachment Figure 6 As an example, the surge protector in this embodiment is compatible with a variety of different forms of on-chip electrodes, which is not limited in this embodiment.

[0069] The structural surge protector of the present invention applies a new thermal tripping structure, which makes the SPD product more reliable and safer while ensuring the original cost.

[0070] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A thermal trip structure, characterized in that: include: An on-chip electrode disposed on the MOV chip; and, a lead-out electrode welded to the electrode on the chip; The chip electrode is provided with a welding boss which is engaged with the lead-out electrode, and a welding convex strip arranged on the top of the welding boss; The front end plane opening of the lead-out electrode forms a welding opening, and the welding opening is embedded in the welding convex strip; The front end plane of the lead-out electrode is pressed downward, and after the welding port and the welding convex strip are engaged, they are fixed by temperature alloy welding to form a release point; When the temperature generated by the degradation of the MOV chip is too high, the lead-out electrode is disconnected from the welding connection with the electrode on the chip, so that the welding joint is released from the pressing and resets itself upward.

2. A thermal release structure according to claim 1, characterized in that: The top surface of the welding boss is low in the front and high in the back to form an inclined surface, and the welding port is welded on the inclined surface; The inclination angle of the inclined surface is the same as the welding angle formed when the lead-out electrode is pressed downward; after the welding opening on the front end plane of the lead-out electrode is pressed downward, it is attached to the inclined surface and fixed by temperature alloy welding; When the temperature generated by the degradation of the MOV chip is too high, the temperature alloy melts, and the lead electrode naturally rises upward under the elastic potential energy generated by the plane downward pressure, disconnecting the welding connection with the electrode on the chip; so that the welding joint is free from the pressure and resets itself upward, causing the external circuit connected to the lead electrode to be in an open circuit state.

3. A thermal release structure according to claim 2, characterized in that: The welding convex strip is arranged in the middle of the inclined surface, the top plane of the welding convex strip is parallel to the electrode on the chip, and the welding ports are embedded on both sides of the welding convex strip; The front end plane of the lead-out electrode is pressed downward so that the welding port is aligned with the welding convex strip and embedded, and the welding port is close to the inclined surface, and then fixed by temperature alloy welding to form a release point at the welding connection point.

4. A thermal release structure according to claim 3, characterized in that: The lower part of the extraction electrode is a vertical part, and the upper part is a horizontal part; The vertical portion extends downward and protrudes out to connect with an external circuit; The horizontal portion is a horizontal plate surface, the rear end of which is bent and connected to the vertical portion, and the front end of which is provided with the welding port; the welding port opens to the rear end to form a fork-shaped welding port; The horizontal plate surface is pressed downward so that the fork-shaped welding opening is nested on the welding boss and fixed by temperature alloy welding, thereby forming a tripping point at the welding connection point.

5. A thermal release structure according to claim 4, characterized in that: The opening of the fork-shaped welding port is a rectangular fitting surface that fits the welding convex strip, and the inner diameter of the rectangular fitting surface is greater than the outer diameter of the welding convex strip.

6. A thermal release structure according to claim 5, characterized in that: The outer edges on both sides of the fork-shaped welding opening are recessed inward to form a sawtooth structure or a wave-like structure; the starting and ending positions of the sawtooth structure or the wave-like structure are flush with the starting and ending positions of the middle opening of the fork-shaped welding opening.

7. A thermal release structure according to claim 5, characterized in that: The height of the side wall of the welding protrusion is greater than the plate surface thickness of the fork-shaped welding opening. After the fork-shaped welding opening is welded on the welding protrusion, the welding protrusion protrudes out of the welding plane or is flush with the welding plane.

8. A surge protector, characterized in that: It comprises a thermal trip structure as described in any one of claims 1 to 7, and also comprises a shell as a fixed structure, wherein an MOV chip is arranged in the shell; the thermal trip structure comprises an on-chip electrode arranged on the MOV chip, and an extraction electrode welded on the on-chip electrode; a welding boss engaged with the extraction electrode is arranged on the on-chip electrode, the top of the welding boss is low in front and high in the back to form an inclined surface, and a welding convex strip is arranged in the middle of the inclined surface; the front end plane opening of the extraction electrode forms a fork-shaped welding opening, and the fork-shaped welding opening is embedded in the welding convex strip.

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