Thermistor with thermal protection structure

Abstract

The utility model discloses a thermistor with thermal protection structure belongs to electronic component technical field. The utility model discloses a thermistor body, thermistor body has thermistor chip, is provided with protection mechanism on thermistor chip, and protection mechanism is composed of insulating spacer, bimetal and movable electrode, is provided with insulating spacer on thermistor chip, is provided with bimetal on insulating spacer, and the through -hole is seted up in bimetal, and the through -hole is cooperated with movable electrode. The utility model discloses through setting up insulating spacer, bimetal and movable electrode and the mechanical type thermal protection mechanism of composition, when thermistor overheats because of failure, heat is rapidly conducted to bimetal, and it produces instantaneous deformation when reaching predetermined critical temperature, drives movable electrode and electrode terminal mechanical separation, thereby permanently, physically cuts off the current passage, and the possibility of the deteriorated thermistor continuous energization is eliminated, and the accident is effectively avoided.

Description

Technical Field

[0001] This utility model relates to the field of electronic components technology, specifically to a thermistor with a thermal protection structure. Background Technology

[0002] A thermistor is a widely used overvoltage protection component in electronic circuits. Its core is a thermistor chip with nonlinear volt-ampere characteristics, typically made of metal oxides such as zinc oxide. When a surge voltage or overvoltage occurs in a circuit, the thermistor quickly conducts, dissipating excessive energy and protecting downstream precision electronic equipment. However, after repeated or severe overvoltage impacts, the performance of the thermistor may gradually deteriorate, manifested as a gradual increase in leakage current. At the operating voltage, this deterioration leads to increased power consumption, causing a sustained rise in temperature. If the generated heat cannot be dissipated in time, the thermistor's temperature may exceed safety limits, posing a risk of overheating, smoking, or even fire. Therefore, a compact, reliable thermal protection solution capable of permanently cutting off faulty circuits is needed, integrated within the thermistor, to fundamentally improve the component's safety and reliability. Utility Model Content

[0003] The purpose of this invention is to provide a thermistor with a thermal protection structure, which solves the problem of the inability to automatically and permanently cut off the circuit when overheating by setting an insulating pad, a bimetallic strip and a movable electrode.

[0004] This utility model is achieved through the following technical solution: This utility model relates to a thermistor with a thermal protection structure, comprising a thermistor body, a thermistor chip, a protection mechanism on the thermistor chip, the protection mechanism being composed of an insulating pad, a bimetallic strip, and a movable electrode. The thermistor chip is provided with an insulating pad, the insulating pad is provided with a bimetallic strip, the bimetallic strip has a through hole, and the movable electrode is fitted inside the through hole.

[0005] Furthermore, the bimetallic strip consists of a first metal strip and a second metal strip, with the second metal strip connected to the top of the first metal strip.

[0006] Furthermore, the thermistor body also has two electrode terminals, which are respectively located on both sides of the thermistor chip, with the bottom of the movable electrode in contact with the electrode terminals.

[0007] Furthermore, a moving contact is formed between the active electrode and the electrode terminal.

[0008] Furthermore, a second lead is electrically connected to the top of the active electrode, and conductive adhesive is coated between the second lead and the active electrode.

[0009] Furthermore, a conductive sheet is provided at the bottom of the electrode terminal, and the conductive sheet is electrically connected to the first lead through conductive adhesive.

[0010] Furthermore, a stationary contact is formed between the first lead and the electrode terminal.

[0011] Furthermore, the thermistor chip is coated with an epoxy resin encapsulation layer, and the protection mechanism is located within the epoxy resin encapsulation layer.

[0012] This utility model has the following beneficial effects: This utility model employs a mechanical thermal protection mechanism consisting of an insulating pad, a bimetallic strip, and a movable electrode. When the thermistor overheats due to a fault, the heat is rapidly conducted to the bimetallic strip, which deforms instantaneously when it reaches a predetermined critical temperature. This causes the movable electrode to mechanically separate from the electrode terminal, thereby permanently and physically cutting off the current path. This eliminates the possibility of a deteriorated thermistor continuing to be energized, effectively preventing accidents and greatly enhancing the overall safety and reliability of electrical equipment. This invention utilizes the inherent physical properties of bimetallic strips, eliminating the need for additional electronic control circuits or expensive materials. It features a simple and compact structure that is easy to automate. The active electrode passes through a through-hole in the bimetallic strip and is directly driven by the deformation of the bimetallic strip. The transmission path is direct, and the action response is rapid and definite, avoiding the risk of malfunction or failure.

[0013] Of course, any product implementing this utility model does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of a thermistor. Figure 2 This is a schematic diagram of the internal structure of the thermistor body. Figure 3 This is a schematic diagram of the structure of the insulating pad and the first metal sheet; Figure 4 This is a schematic diagram of the structure of a thermistor chip.

[0015] In the figure: 1. Thermistor body; 2. Thermistor chip; 3. First lead; 4. Second lead; 5. Epoxy resin encapsulation layer; 6. Insulating gasket; 7. First metal sheet; 701. Through hole; 8. Second metal sheet; 9. Movable electrode; 10. Conductive adhesive; 11. Electrode terminal; 12. Conductive sheet. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0017] Please see Figure 1-4 This utility model provides a technical solution: a thermistor with a thermal protection structure, including a thermistor body 1, a thermistor chip 2, and two electrode terminals 11 respectively disposed on opposite sides of the thermistor chip 2. The thermistor chip 2 has a protection mechanism consisting of an insulating pad 6, a bimetallic strip, and a movable electrode 9. The insulating pad 6 is made of high-temperature resistant and highly insulating ceramic, isolating the bimetallic strip from the thermistor chip 2, preventing short circuits, and effectively conducting heat to the bimetallic strip. The thermistor chip 2 has the insulating pad 6, and the bimetallic strip is disposed on the insulating pad 6. The bimetallic strip consists of a first metal strip 7 and a second metal strip 8, with the second metal strip 8 connected to the top of the first metal strip 7. The second metal strip 8 and the first metal strip 7 are welded together. The bimetallic strip has a through hole 701, and the movable electrode 9 is fitted inside the through hole 701. The movable electrode 9 is made of highly conductive copper. The bottom of the active electrode 9 contacts the electrode terminal 11, forming a moving contact between the active electrode 9 and the electrode terminal 11. At room temperature, the bottom of the active electrode 9 maintains physical contact with the electrode terminal 11 below, thus forming a closed circuit. The top of the active electrode 9 is electrically connected to the second lead 4, and conductive adhesive 10 is coated between the second lead 4 and the active electrode 9. The conductive adhesive 10 ensures the stability of the connection and low resistance. When the thermistor body 1 ages or deteriorates due to overvoltage impact, or when its power consumption increases sharply due to continuous abnormal voltage, its temperature will rise abnormally. This heat is quickly conducted to the bimetallic strip through the thermistor chip 2 and the insulating pad 6. When the temperature rises to the predetermined protection temperature, due to the difference in the thermal expansion coefficients of the first metal sheet 7 and the second metal sheet 8, the bimetallic strip will undergo instantaneous and significant deformation. The upward bending of the bimetallic strip will drive the active electrode 9, which passes through its through hole 701, to move upward together. The bottom of the active electrode 9 is thus mechanically separated from the electrode terminal 11 that was originally in contact, and the moving contact is forcibly disconnected.

[0018] A conductive sheet 12 is provided at the bottom of the electrode terminal 11. The conductive sheet 12 increases the conductivity. The conductive sheet 12 is electrically connected to the first lead 3 through the conductive adhesive 10. The first lead 3 and the electrode terminal 11 form a static contact. The thermistor chip 2 is coated with an epoxy resin encapsulation layer 5. The protection mechanism is located inside the epoxy resin encapsulation layer 5. The epoxy resin encapsulation layer 5 provides good mechanical strength, insulation and environmental protection, and can also effectively transfer the heat generated inside.

[0019] The preferred embodiments of this utility model disclosed above are merely illustrative of the present utility model. These preferred embodiments do not exhaustively describe all details, nor do they limit the utility model to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of this utility model, thereby enabling those skilled in the art to better understand and utilize it. This utility model is limited only by the claims and their full scope and equivalents.

Claims

1. A thermistor with a thermal protection structure, comprising a thermistor body (1), characterized in that: The thermistor body (1) has a thermistor chip (2), and a protection mechanism is provided on the thermistor chip (2). The protection mechanism consists of an insulating pad (6), a bimetallic strip and a movable electrode (9). The thermistor chip (2) is provided with an insulating pad (6), the insulating pad (6) is provided with a bimetallic strip, the bimetallic strip is provided with a through hole (701), and the movable electrode (9) is fitted inside the through hole (701).

2. A thermistor with a thermal protection structure according to claim 1, characterized in that, The bimetallic strip is composed of a first metal strip (7) and a second metal strip (8), with the second metal strip (8) connected to the top of the first metal strip (7).

3. A thermistor with a thermal protection structure according to claim 1, characterized in that, The thermistor body (1) also has electrode terminals (11), and there are two electrode terminals (11). The two electrode terminals (11) are respectively disposed on both sides of the thermistor chip (2), and the bottom of the active electrode (9) is in contact with the electrode terminals (11).

4. A thermistor with a thermal protection structure according to claim 3, characterized in that, A moving contact is formed between the active electrode (9) and the electrode terminal (11).

5. A thermistor with a thermal protection structure according to claim 1, characterized in that, The top of the active electrode (9) is electrically connected to a second lead (4), and conductive adhesive (10) is coated between the second lead (4) and the active electrode (9).

6. A thermistor with a thermal protection structure according to claim 3, characterized in that, A conductive sheet (12) is provided at the bottom of the electrode terminal (11), and the conductive sheet (12) is electrically connected to the first lead (3) through conductive adhesive (10).

7. A thermistor with a thermal protection structure according to claim 6, characterized in that, A stationary contact is formed between the first lead (3) and the electrode terminal (11).

8. A thermistor with a thermal protection structure according to claim 1, characterized in that, The thermistor chip (2) is coated with an epoxy resin encapsulation layer (5), and the protection mechanism is located inside the epoxy resin encapsulation layer (5).

Images