Elastically sprung thermal compensating piezoresistor

Abstract

The utility model relates to electronic component technical field especially a kind of elastic wire elastic opening heat preservation type piezoresistor, overcome the problem that existing fuse fuse form resistance overheating cannot be quickly and completely disconnected pin and electrode, with piezoresistor chip, first electrode and second electrode respectively arranged in the two side surfaces of piezoresistor chip and the first pin and the second pin respectively electrically connected first electrode and second electrode, piezoresistor further has elastic wire, elastic wire has elastic part and first elastic foot and second elastic foot from elastic part stretch, first elastic foot is electrically connected with first electrode through first low-temperature solder joint and is electrically connected with first pin through second low-temperature solder joint, elastic wire second elastic foot is positioned after exerting external force to make elastic part of elastic wire produce elastic deformation, and preset force is formed to first elastic foot by elastic deformation of elastic part and elastic opening;When first low-temperature solder joint and second low-temperature solder joint are melted by heat, first elastic foot is elastic and thus disconnects the electrical connection of first pin and first electrode.

Description

Technical Field

[0001] This utility model relates to the field of electronic component technology, and in particular to a heat-resistant varistor with a spring-loaded flexible conductor. Background Technology

[0002] Varistors are commonly used electronic components in electronic circuits to prevent overvoltage from damaging other components. When electronic circuits are frequently subjected to overvoltage, varistors may malfunction and their performance may degrade. In severe cases, varistors may break down or burn, thereby damaging other surrounding components.

[0003] Current technology includes a type of varistor with overheat protection. A thermal fuse is connected to one pin of the varistor. One end of the thermal fuse is soldered to an electrode, and the other end is soldered to the pin. The part of the thermal fuse, except for the soldered end to the electrode, is insulated and heated by the varistor body. When the current in the circuit is too large, causing the varistor body to generate high temperature, the thermal fuse melts and disconnects the pin, achieving circuit break protection. However, this thermal fuse melting structure has a relatively short melting distance of only 1-2mm. The melting point is prone to arcing, which prevents the circuit from being quickly and completely disconnected, thus not meeting the application requirements of some customers. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide a thermally insulating varistor with a spring-loaded flexible conductor, which overcomes the problem that existing thermally insulating varistors with fuse-blown fuses cannot quickly and completely disconnect the pins from the electrodes when overheating.

[0005] The technical solution adopted by this utility model to solve its technical problem is: a thermally insulating varistor with an elastic conductor that springs open, comprising a varistor chip, a first electrode and a second electrode respectively disposed on both sides of the varistor chip, a first pin electrically connected to the first electrode and a second pin electrically connected to the second electrode, the varistor having an insulating layer wrapped around the outside, the varistor also having an elastic conductor, the elastic conductor having an elastic part and a first spring-loaded leg and a second spring-loaded leg extending from the elastic part, the first spring-loaded leg being electrically connected to the first electrode via a first low-temperature solder joint and to the first pin via a second low-temperature solder joint, the second spring-loaded leg of the elastic conductor being positioned after an external force is applied so that the elastic part of the elastic conductor undergoes elastic deformation, and the elastic deformation of the elastic part forms a preset force to spring open the first spring-loaded leg;

[0006] When the first low-temperature solder joint and the second low-temperature solder joint melt due to heat, the first spring-loaded pin pops open, thereby disconnecting the electrical connection between the first pin and the first electrode.

[0007] Specifically, the varistor also has an inner mounting base disposed on the first electrode, and the second spring leg of the elastic wire is positioned on the stop block or positioning groove of the inner mounting base after an external force is applied.

[0008] Specifically, the elastic part of the elastic conductor is in the shape of a helical torsion spring, and the inner mounting base is provided with a torsion spring post, with the elastic part sleeved on the torsion spring post.

[0009] Specifically, before being heated and melted, the second low-temperature solder joint is located at the end of the first spring and the end of the first pin.

[0010] Specifically, the inner mounting base is provided with a first pin slot for accommodating a portion of the first pin.

[0011] Specifically, the outer opening of the inner mounting base has a stepped stop, and the varistor also has a cover plate that seals the stop.

[0012] Specifically, the insulating layer is encapsulated outside the inner mounting base and the cover plate.

[0013] Depending on the different application requirements of some circuits for thermally insulating varistors, the varistor also has a third pin. The inner end of the third pin is soldered to the first electrode and the first spring pin via the first low-temperature solder joint. The first pin, the second pin, and the third pin have portions that expose the insulating layer.

[0014] Furthermore, the inner mounting base is provided with a third pin slot for accommodating a portion of the third pin.

[0015] The beneficial effects of this utility model are as follows: This utility model sets two low-temperature solder joints, generally low-temperature solder joints, on the conductive connector connected to the first electrode and the first pin, and makes the conductive connector the first spring of the elastic wire. The elastic force of the elastic wire causes the conductive connector to quickly displace after the solder joint overheats and melts. This displacement is roughly a swing-side shift, which enables the first electrode and the first pin to be quickly and completely disconnected. Specifically, this is manifested as follows:

[0016] 1. When the product is subjected to the same limiting current and load ratio overload, this utility model shortens the fusing time by more than 50%;

[0017] II. Improved reliability of AC overload protection;

[0018] Third, DC overload can realize the mechanical arc extinguishing function.

[0019] Fourth, a small deformation of the elastic part of the elastic conductor can achieve a large swing of the first spring (conductive connector), thus achieving a longer melting distance with a small elastic deformation. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] Figure 1 This is the front view of Embodiment 1;

[0022] Figure 2 yes Figure 1 View from direction A;

[0023] Figure 3 This is a perspective view of Example 1 with part of the insulation layer and part of the cover plate removed;

[0024] Figure 4 This is a perspective view of the exposed elastic conductor in Example 1;

[0025] Figure 5 This is a perspective view of Embodiment 1 with the elastic wire exposed and the first spring-loaded foot in the spring-loaded state;

[0026] Figure 6 This is a front view of Example 2 with part of the insulation layer and part of the cover plate removed;

[0027] Figure 7 This is a front view of Embodiment 2 with part of the insulation layer and part of the cover plate removed and the first spring-loaded foot in the spring-loaded state.

[0028] In the diagram: 1. Pressure-sensitive chip; 2. First electrode; 3. First pin; 4. Second pin; 5. Insulating layer;

[0029] 6. Inner mounting base; 6-1. Base plate; 6-2. Welding hole; 6-3. Stop block; 6-4. Positioning groove; 6-5. Torsion spring column; 6-6. First pin groove; 6-7. Stop; 6-8. Third pin groove.

[0030] 7. Elastic conductor; 7-1. Elastic part; 7-2. First spring foot; 7-3. Second spring foot;

[0031] 8. Cover plate; 9. First low-temperature solder joint; 10. Second low-temperature solder joint; 11. Third pin. Detailed Implementation

[0032] The present invention will now be described in further detail with reference to the accompanying drawings and preferred embodiments. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.

[0033] Example 1:

[0034] A type of heat-resistant varistor with a spring-loaded flexible conductor, as shown in the attached figure. Figure 1 and attached Figure 2 It has two pins, and its internal structure in normal operation is shown in the attached figure. Figure 3 and attached Figure 4The varistor has a varistor chip 1, a first electrode 2 and a second electrode respectively disposed on both sides of the varistor chip 1, a first pin 3 electrically connected to the first electrode 2 and a second pin 4 electrically connected to the second electrode. The varistor has an insulating layer 5 wrapped around the outside. The first pin 3 and the second pin 4 have portions that expose the insulating layer 5. The varistor also has an inner mounting base 6 disposed on the first electrode 2, an elastic wire 7 mounted on the inner mounting base 6 and a cover plate 8 covering the outer opening of the inner mounting base 6. The inner mounting base 6 has a base plate 6-1 that contacts the first electrode 2.

[0035] The elastic wire 7 is located in the cavity formed by the inner mounting base 6 and the cover plate 8. The elastic wire 7 has an elastic part 7-1 and a first spring foot 7-2 and a second spring foot 7-3 extending from the elastic part 7-1. The first spring foot 7-2 is a conductive connector between the first electrode 2 and the first pin 3. The first spring foot 7-2 is electrically connected to the first electrode 2 via a first low-temperature solder joint 9 and to the first pin 3 via a second low-temperature solder joint 10. The bottom plate 6-1 of the inner mounting base 6 has a soldering hole 6-2 to accommodate the first low-temperature solder joint 9. After an external force is applied, the second spring foot 7-3 of the elastic wire 7 is positioned on the stop block 6-3 of the inner mounting base 6 so that the elastic part 7-1 of the elastic wire 7 undergoes elastic deformation. The elastic deformation of the elastic part 7-1 forms a preset force to spring open the first spring foot 7-2.

[0036] When the first low-temperature solder joint 9 and the second low-temperature solder joint 10 melt and break due to heat, the first spring pin 7-2 springs open, thereby disconnecting the electrical connection between the first pin 3 and the first electrode 2. The state after melting is shown in the attached figure. Figure 5 .

[0037] The specific structure is further characterized by the following: the elastic part 7-1 of the elastic conductor 7 is in the shape of a helical torsion spring; the inner mounting base 6 is provided with a torsion spring post 6-5, and the elastic part 7-1 is sleeved on the torsion spring post 6-5; the second low-temperature solder joint 10 is located at the end of the first spring foot 7-2 and the end of the first pin 3; the inner mounting base 6 is provided with a first pin groove 6-6 for accommodating part of the first pin 3; the outer opening of the inner mounting base 6 has a stepped stop 6-7, and the cover plate 8 is sealed on the stop 6-7; the insulating layer 5 is enclosed on the inner mounting base 6 and the cover plate 8.

[0038] Example 2:

[0039] Example 2 has one more pin than Example 1 in appearance, and its internal structure is as follows. Figure 6 An outward-leading pin is added at the first low-temperature solder joint 9. That is, the varistor also has a third pin 11. The inner end of the third pin 11 is soldered to the first electrode 2 and the first spring pin 7-2 via the first low-temperature solder joint 9. The third pin 11 has a portion that exposes the insulating layer 5. The inner mounting base 6 is provided with a third pin groove 6-8 for accommodating part of the third pin 11.

[0040] The first spring foot 7-2 is made into a curved shape to save space, and the second spring foot 7-3 of the elastic wire 7 is positioned in the positioning groove 6-4.

[0041] Due to the design requirements of the pin position, the positions of the first low-temperature solder joint 9 and the second low-temperature solder joint 10 on the first spring pin 7-2 in Embodiment 2 are different from those in Embodiment 1. The second low-temperature solder joint 10 in Embodiment 2 is closer to the elastic part 7-1, while the first low-temperature solder joint 9 in Embodiment 1 is closer to the elastic part 7-1.

[0042] In addition, the first low-temperature solder joint 9 and the second low-temperature solder joint 10 of this invention are solder joints with a temperature of 120 to 200°C, while conventional solder joints have a temperature of around 140°C.

[0043] The above description is only a specific embodiment of the present utility model. Various examples and illustrations do not constitute a limitation on the substantive content of the present utility model. Those skilled in the art can make modifications or variations to the above-described specific embodiments after reading the description without departing from the essence and scope of the utility model.

Claims

1. A heat-resistant varistor with a spring-loaded flexible conductor, comprising a varistor chip (1), a first electrode (2) and a second electrode respectively disposed on both sides of the varistor chip (1), a first pin (3) electrically connected to the first electrode (2) and a second pin (4) electrically connected to the second electrode, the varistor having an insulating layer (5) wrapped around the outside, characterized in that: The varistor also has an elastic wire (7), which has an elastic part (7-1) and a first spring-loaded foot (7-2) and a second spring-loaded foot (7-3) extending from the elastic part (7-1). The first spring-loaded foot (7-2) is electrically connected to the first electrode (2) via a first low-temperature solder joint (9) and electrically connected to the first pin (3) via a second low-temperature solder joint (10). The second spring-loaded foot (7-3) of the elastic wire (7) is positioned after an external force is applied so that the elastic part (7-1) of the elastic wire (7) undergoes elastic deformation. The elastic deformation of the elastic part (7-1) forms a preset force to spring open the first spring-loaded foot (7-2). When the first low-temperature solder joint (9) and the second low-temperature solder joint (10) are heated and melted, the first spring pin (7-2) springs open, thereby disconnecting the electrical connection between the first pin (3) and the first electrode (2).

2. The heat-resistant varistor with elastic conductor spring-back as described in claim 1, characterized in that: The varistor also has an inner mounting base (6) disposed on the first electrode (2), and the second spring foot (7-3) of the elastic wire (7) is positioned on the stop (6-3) or in the positioning groove (6-4) of the inner mounting base (6) after an external force is applied.

3. The heat-resistant varistor with elastic conductor spring-back as described in claim 2, characterized in that: The elastic part (7-1) of the elastic conductor (7) is in the shape of a helical torsion spring, and the inner mounting base (6) is provided with a torsion spring post (6-5), and the elastic part (7-1) is sleeved on the torsion spring post (6-5).

4. The heat-resistant varistor with elastic conductor spring-back as described in claim 2, characterized in that: The inner mounting base (6) is provided with a first pin slot (6-6) for accommodating a portion of the first pin (3).

5. The heat-resistant varistor with elastic conductor spring-back as described in claim 2, characterized in that: The inner mounting base (6) has a stepped stop (6-7) at its outer opening, and the varistor also has a cover plate (8) that is sealed on the stop (6-7).

6. The heat-resistant varistor with elastic conductor spring-back as described in claim 5, characterized in that: The insulating layer (5) is enclosed outside the inner mounting base (6) and the cover plate (8).

7. The heat-resistant varistor with elastic conductor spring-back as described in claim 1, characterized in that: Before being heated and melted, the second low-temperature solder joint (10) is located at the end of the first spring (7-2) and the end of the first pin (3).

8. The heat-resistant varistor with elastic conductor spring-back as described in claim 2, characterized in that: The first pin (3) and the second pin (4) have portions that expose the insulating layer (5). The varistor also has a third pin (11). The inner end of the third pin (11) is soldered to the first electrode (2) and the first spring pin (7-2) via the first low-temperature solder joint (9). The third pin (11) has portions that expose the insulating layer (5).

9. The heat-resistant varistor with elastic conductor spring-back as described in claim 8, characterized in that: The inner mounting base (6) is provided with a third pin slot (6-8) for accommodating a portion of the third pin (11).

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