Repeatable reflow soldering temperature fuse

Abstract

The utility model relates to the technical field of temperature fuses, and especially relates to a repeatable reflow soldering temperature fuse. A switching element is additionally arranged, the switching element is provided with an abutting portion used for abutting against the other end of a metal elastic piece, a first matching portion arranged corresponding to a first position and a second matching portion arranged corresponding to a second position, and the first matching portion and the second matching portion are both used for being matched with a matched portion. Meanwhile, due to the fact that the switching element is provided with the abutting portion used for abutting against the other end of the metal elastic piece, switching between abutting connection and non-abutting connection with the other end of the metal elastic piece is achieved. The utility model can be applied to printed circuits, household appliances, illumination, automobiles, heaters, reflow soldering, wave soldering and manual soldering, and can overcome and reduce the quality loss caused by soldering to the greatest extent.

Description

Technical Field

[0001] The utility model relates to the technical field of temperature fuses, in particular to a temperature fuse capable of repeated reflow soldering. Background Art

[0002] Whether it is now or in the future, the installation of electronic components in the printed circuit industry generally adopts an automated production mode of pre-covering the circuit board with solder - the robot automatically places the electronic components - reflow soldering. The conventional reflow soldering temperature range is 240℃ to 265℃, lasting 30 seconds to 60 seconds (JEDEC standard), and the reflow soldering temperature of some high-temperature solder products is 275℃ to 295℃, so when installing the temperature fuse, it will cause the temperature fuse to operate during this process. In addition, the conventional temperature fuse is a one-time protection product, which is a major obstacle to its application.

[0003] A thermal fuse that can be used for reflow soldering is known from patent CN108475601B. This fuse needs to put the activation component in a static state before soldering to prevent triggering during soldering, and put the activation component in an activated state after soldering. Since it is a disposable product, it can only be triggered once. During the reflow soldering process, there may be situations where the soldering quality is unqualified and secondary soldering is required, and the fuse needs to be replaced. Therefore, it has great limitations and is prone to cause great quality cost losses. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide a temperature fuse capable of repeated reflow soldering.

[0005] In order to solve the above technical problems, the technical solution adopted by the utility model is:

[0006] A repeatable reflow soldering temperature fuse comprises at least two electrodes and a metal elastic member for connecting the two electrodes, wherein one end of the metal elastic member is connected to one electrode, and the other end of the metal elastic member is connected to the other electrode via a temperature sensing element, and further comprises a switching element, wherein the switching element is provided with abutting portion for abutting against the other end of the metal elastic member, and a first matching portion respectively arranged corresponding to a first position and a second matching portion corresponding to a second position, wherein the first matching portion and the second matching portion both match with a matched portion.

[0007] Furthermore, the mated portion includes a first mated portion, and when the first mated portion is mated with the first mating portion, the abutting portion on the switching element does not abut against the other end of the metal elastic part; when the first mated portion is mated with the second mating portion, the abutting portion on the switching element abuts against the other end of the metal elastic part.

[0008] Furthermore, the switching element is also provided with a third matching portion corresponding to the third position, and the matched portion also includes a second matched portion; when the first matched portion is matched with the first matching portion, the abutting portion on the switching element does not abut against the other end of the metal elastic part, and the third matching portion is matched with the second matched portion so that the third matching portion does not abut against the metal elastic part; when the first matched portion is matched with the second matching portion, the abutting portion on the switching element abuts against the other end of the metal elastic part.

[0009] Furthermore, the mated portion includes a first mated portion and a second mated portion; when the first mated portion is mated with the first mating portion, the abutting portion on the switching element does not abut against the other end of the metal elastic part; when the second mated portion is mated with the second mating portion, the abutting portion on the switching element abuts against the other end of the metal elastic part.

[0010] Furthermore, the switching element is also provided with a third matching portion corresponding to the third position, and the matched portion also includes a third matched portion; when the first matched portion matches with the first matching portion, the abutting portion on the switching element does not abut against the other end of the metal elastic part, and the third matching portion matches with the third matched portion so that the third matching portion does not abut against the metal elastic part; when the second matched portion matches with the second matching portion, the abutting portion on the switching element abuts against the other end of the metal elastic part.

[0011] Furthermore, the first matching portion is a supporting portion.

[0012] Furthermore, it also includes a shell, the first matched portion is an inner side wall of the shell close to the abutting portion, and the abutting portion is interference-fitted with the inner side wall of the shell close to the abutting portion.

[0013] Furthermore, it also includes a shell, the shell is provided with a first mounting portion, the switching element is provided with a second mounting portion that matches the first mounting portion, and the matched portion is provided on the shell.

[0014] Furthermore, an extension portion is provided on the inner side wall of the shell, and the mated portion is provided at the free end of the extension portion.

[0015] Furthermore, the first mounting portion is a through hole provided on two opposite side walls of the housing, and the second mounting portion is a rotating shaft provided on two opposite side walls of the switching element, and the rotating shaft passes through the through hole so that the switching element can be rotatably provided on the housing.

[0016] Furthermore, a guide groove is provided on the inner side wall of the shell, and a guide step matched with the guide groove is provided on the outer side wall of the switching element.

[0017] Furthermore, the first mating portion and the second mating portion are both limiting grooves, and the mated portion is a limiting protrusion.

[0018] Furthermore, a protrusion is provided at the other end of the metal elastic member, and when the engaged portion is engaged with the second engaging portion, the abutting portion on the switching element abuts against the protrusion.

[0019] Furthermore, it also includes a base, which is arranged at one end of the shell away from the switching element, and the shell is provided with notches on both sides of the end away from the switching element. A first clamping portion is provided in the middle position of the end of the shell away from the switching element, and the opposite sides of the base are respectively provided with a step portion adapted to the notch, and the base is provided with a second clamping portion adapted to the first clamping portion.

[0020] The beneficial effects of the utility model are:

[0021] The utility model provides a repeatable reflow soldering temperature fuse, which adds a switching element, and is provided with a supporting portion for abutting against the other end of the metal elastic part, and a first matching portion and a second matching portion respectively corresponding to the first position and the second matching portion corresponding to the second position on the switching element, wherein the first matching portion and the second matching portion are both used to match with the matched portion to realize the switching function of the switching element, and at the same time, because the switching element is provided with a supporting portion for abutting against the other end of the metal elastic part, that is, the switching between abutting and non-abutting against the other end of the metal elastic part is realized, when the repeatable reflow soldering temperature fuse is installed on the printed circuit to be soldered, it needs to be set to a welding state to prevent the repeatable reflow soldering temperature fuse from activating the over-temperature protection function, so that the supporting portion abuts against the other end of the metal elastic part; after soldering is completed, it needs to be set to a working state so that the supporting portion does not abut against the other end of the metal elastic part to exert its thermal protection function. When it needs to be used again and soldering is required, it can be set to a soldering state again. The utility model can be applied to printed circuits, household appliances, lighting, automobiles, heaters, reflow soldering, wave soldering, and manual soldering to overcome and minimize the quality loss caused by soldering. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of a repetitive reflow soldering thermal fuse of the utility model from one perspective;

[0023] Figure 2 It is a structural schematic diagram of another perspective of a repeatable reflow soldering thermal fuse of the utility model;

[0024] Figure 3 This is a structural exploded view of a repeatable reflow soldering thermal fuse of the utility model;

[0025] Figure 4It is a cross-sectional view of a repetitive reflow soldering thermal fuse of the utility model during soldering;

[0026] Figure 5 It is a cross-sectional view of a re-flow soldering thermal fuse after soldering according to the utility model;

[0027] Figure 6 It is a cross-sectional view of a repeatable reflow soldering thermal fuse of the utility model when it is triggered;

[0028] Figure 7 It is a cross-sectional view of a reflow soldering thermal fuse of the utility model during re-soldering;

[0029] Description of labels:

[0030] 1. Shell; 11. First mounting portion; 12. First mating portion; 13. Extension portion; 14. Second mating portion; 15. Guide groove; 16. Notch; 2. Base; 21. Step portion; 22. Second clamping portion; 3. Switching element; 31. Second mounting portion; 32. Abutment portion; 33. First mating portion; 34. Second mating portion; 35. Third mating portion; 36. Guide step; 4. Metal elastic member; 41. Protrusion; 5. Electrode sheet a; 6. Electrode sheet b; 7. Temperature sensing element. DETAILED DESCRIPTION

[0031] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in conjunction with the implementation modes and the accompanying drawings.

[0032] Please refer to Figures 1 to 7 The utility model provides a repeatable reflow soldering temperature fuse, comprising at least two electrodes and a metal elastic member for connecting the two electrodes, wherein one end of the metal elastic member is connected to one electrode, and the other end of the metal elastic member is connected to the other electrode through a temperature sensing element, and further comprising a switching element, wherein the switching element is provided with a supporting portion for abutting against the other end of the metal elastic member, and a first matching portion respectively arranged at a first position and a second matching portion corresponding to a second position, wherein the first matching portion and the second matching portion both match with the matched portion.

[0033] From the above description, it can be seen that the beneficial effects of the utility model are:

[0034] The utility model provides a reflowable temperature fuse, which increases a switching element, and is provided with a supporting portion for abutting against the other end of a metal elastic member, and a first matching portion and a second matching portion respectively corresponding to the first position and the second matching portion corresponding to the second position, the first matching portion and the second matching portion are both used to match with the external first matched portion to realize the switching function of the switching element, and at the same time, because the switching element is provided with a supporting portion for abutting against the other end of the metal elastic member, that is, the switching between abutting against and not abutting against the other end of the metal elastic member is realized, when the reflowable temperature fuse is installed on the printed circuit to be welded, it needs to be set to a welding state to prevent the reflowable temperature fuse from activating the over-temperature protection function, so that the supporting portion abuts against the other end of the metal elastic member; after welding is completed, it needs to be set to a working state, so that the supporting portion does not abut against the other end of the metal elastic member, so as to exert its thermal protection function. When it needs to be used again and welding is required, it can be set to a welding state again. The utility model can be applied to printed circuits, household appliances, lighting, automobiles, heaters, reflow soldering, wave soldering, and manual soldering to overcome and minimize the quality loss caused by soldering.

[0035] Furthermore, the mated portion includes a first mated portion, and when the first mated portion is mated with the first mating portion, the abutting portion on the switching element does not abut against the other end of the metal elastic part; when the first mated portion is mated with the second mating portion, the abutting portion on the switching element abuts against the other end of the metal elastic part.

[0036] It can be seen from the above description that, through the above cooperation, only one first matched part is needed to realize the switching function, thereby simplifying the design.

[0037] Furthermore, the switching element is also provided with a third matching portion corresponding to the third position, and the matched portion also includes a third matched portion; when the first matched portion is matched with the first matching portion, the abutting portion on the switching element does not abut against the other end of the metal elastic part, and the third matching portion is matched with the third matched portion so that the third matching portion does not abut against the metal elastic part; when the first matched portion is matched with the second matching portion, the abutting portion on the switching element abuts against the other end of the metal elastic part.

[0038] From the above description, it can be seen that by further adding a third matching portion to cooperate with the third matched portion, a limiting effect can be exerted on the third matching portion, which is equivalent to a secondary limiting effect on the switching element, effectively preventing the metal elastic part from being affected.

[0039] Furthermore, the mated portion includes a first mated portion and a second mated portion; when the first mated portion is mated with the first mating portion, the abutting portion on the switching element does not abut against the other end of the metal elastic part; when the second mated portion is mated with the second mating portion, the abutting portion on the switching element abuts against the other end of the metal elastic part.

[0040] From the above description, it can be seen that through the above cooperation, the first matched part cooperates with the first matching part and the second matched part cooperates with the second matching part to realize the switching function, and the switching stroke can be shortened only through reasonable position design.

[0041] Furthermore, the switching element is also provided with a third matching portion corresponding to the third position, and the matched portion also includes a third matched portion; when the first matched portion matches with the first matching portion, the abutting portion on the switching element does not abut against the other end of the metal elastic part, and the third matching portion matches with the third matched portion so that the third matching portion does not abut against the metal elastic part; when the second matched portion matches with the second matching portion, the abutting portion on the switching element abuts against the other end of the metal elastic part.

[0042] From the above description, it can be seen that by further adding a third matching portion to cooperate with the third matched portion, a limiting effect can be exerted on the third matching portion, which is equivalent to a secondary limiting effect on the switching element, effectively preventing the metal elastic part from being affected.

[0043] Furthermore, the first matching portion is a supporting portion.

[0044] It can be seen from the above description that the first matching portion is used as a supporting portion, which not only has a supporting effect on the metal elastic member, but also has a matching effect with the matched portion, thereby achieving the effect of simplifying the structure.

[0045] Furthermore, it also includes a shell, the first matched portion is an inner side wall of the shell close to the abutting portion, and the abutting portion is interference-fitted with the inner side wall of the shell close to the abutting portion.

[0046] It can be seen from the above description that the limiting effect is achieved by the interference fit between the abutting portion and the first matched portion.

[0047] Furthermore, it also includes a shell, the shell is provided with a first mounting portion, the switching element is provided with a second mounting portion that matches the first mounting portion, and the matched portion is provided on the shell.

[0048] It can be seen from the above description that the matching relationship between the switching element and the matched part is realized through the housing.

[0049] Furthermore, an extension portion is provided on the inner side wall of the shell, and the mated portion is provided at the free end of the extension portion.

[0050] It can be seen from the above description that the mated portion is arranged at the free end of the extending portion, and the extending portion has a certain deformation characteristic, thereby facilitating the reciprocating switching of the switching element.

[0051] Furthermore, the first mounting portion is a through hole provided on two opposite side walls of the housing, and the second mounting portion is a rotating shaft provided on two opposite side walls of the switching element, and the rotating shaft passes through the through hole so that the switching element can be rotatably provided on the housing.

[0052] It can be seen from the above description that, through the above structure, the switching element can be rotatable on the housing, thereby realizing the switching function.

[0053] Furthermore, a guide groove is provided on the inner side wall of the shell, and a guide step matched with the guide groove is provided on the outer side wall of the switching element.

[0054] It can be seen from the above description that the cooperation between the guide groove and the guide step can play a role of limiting the position during the reciprocating motion of the switching element, and also has the function of preventing fooling and reverse installation.

[0055] Furthermore, the first mating portion and the second mating portion are both limiting grooves, and the mated portion is a limiting protrusion.

[0056] It can be seen from the above description that the limiting groove is used as the first matching part and the second matching part, and the limiting protrusion is used as the matched part. The concave-convex matching is adopted, which has stability and avoids misalignment.

[0057] Furthermore, a protrusion is provided at the other end of the metal elastic member, and when the engaged portion is engaged with the second engaging portion, the abutting portion on the switching element abuts against the protrusion.

[0058] From the above description, it can be seen that by setting the protrusion, the protruding part has a certain elasticity, which helps the first mating part and the second mating part of the switching element to engage with the mated part when the abutting part contacts the protruding part, and prevents it from being too rigid and unable to be engaged when there is a size difference.

[0059] Furthermore, it also includes a base, which is arranged at one end of the shell away from the switching element, and the shell is provided with notches on both sides of the end away from the switching element. A first clamping portion is provided in the middle position of the end of the shell away from the switching element, and the opposite sides of the base are respectively provided with a step portion adapted to the notch, and the base is provided with a second clamping portion adapted to the first clamping portion.

[0060] It can be seen from the above description that the cooperation between the notch and the step portion plays a limiting role, and the clamping is achieved through the cooperation between the first clamping portion and the second clamping portion.

[0061] Please refer to Figures 1 to 7 , Embodiment 1 of the present utility model is:

[0062] like Figures 1 to 3 The utility model provides a reflow soldering temperature fuse, which is installed on a circuit board to be soldered. When in use, it needs to be set to a soldering state to prevent the reflow soldering temperature fuse from activating an over-temperature protection function. After the reflow soldering temperature fuse is soldered, it needs to be set to a working state to exert its protection function. When it needs to be used again and soldering is required, it can be set to a soldering state again.

[0063] The specific structure of the above-mentioned repeatable reflow soldering temperature fuse includes a shell 1, a base 2, a switching element 3, two electrodes and a metal elastic member 4 for connecting the two electrodes; the shell 1 is provided with a first mounting portion 11, the switching element 3 is provided with a second mounting portion 31 matched with the first mounting portion 11, the first mounting portion 11 is a through hole provided on the opposite side walls of the shell, the second mounting portion 31 is a rotating shaft provided on the opposite side walls of the switching element, and the rotating shaft is penetrated in the through hole so that the switching element can be rotatably provided on the shell. In this embodiment, the rotating shaft can be integrally formed on the opposite side walls of the switching element, or it can be provided in the form of a latch, that is, a through hole is provided on the opposite side walls of the switching element, and a latch is provided through the through hole, and this method is convenient for assembly.

[0064] The two electrodes are electrode sheet a5 and electrode sheet b6, the metal elastic member 4 is a spring, and the switching element 3 is a button; one end of the spring is connected to the electrode sheet a5, and the other end of the spring is connected to the electrode sheet b6 through the temperature sensing element 7.

[0065] The switching element 3 is provided with abutting portion 32 for abutting against the other end of the metal elastic member, and a first matching portion 33 corresponding to the first position, a second matching portion 34 corresponding to the second position, and a third matching portion 35 corresponding to the third position, respectively. The first matching portion 33 and the second matching portion 34 are both used to match with an external matched portion.

[0066] Specifically, the mated part includes a first mated part 12. When the first mated part 12 is mated with the first mating part 33, the abutting part 32 on the switching element does not abut against the other end of the metal elastic part 4; when the first mated part 12 is mated with the second mating part 34, the abutting part 32 on the switching element abuts against the other end of the metal elastic part 4.

[0067] In this embodiment, an extension portion 13 is provided on the inner side wall of the housing 1, and the matched portion is provided at the free end of the extension portion 13. The first matching portion 33 and the second matching portion 34 are both limiting grooves, wherein the first matching portion is a working limiting groove, and the second matching portion is a welding limiting groove; the first matched portion 12 is a limiting protrusion, i.e., a limiting block. The limiting groove is used as the first matching portion and the second matching portion, and the limiting protrusion is used as the matched portion. The concave-convex matching is adopted, which has stability and avoids misalignment.

[0068] When the first matched portion 12 matches with the first matching portion 33, the third matching portion 35 matches with the second matched portion 14 so that the third matching portion 35 does not abut against the metal elastic member 4. By further adding a third matching portion to match with the external second matched portion, the third matching portion can be limited to prevent the metal elastic member from being affected.

[0069] The inner wall of the housing 1 is provided with a guide groove 15, and the outer wall of the switching element 3 is provided with a guide step 36 adapted to the guide groove 15. The cooperation between the guide groove and the guide step can play a role of limiting the switching element during the reciprocating motion, and also has the function of preventing fooling and reverse installation.

[0070] The other end of the metal elastic member 4 is provided with a protrusion 41, and when the first matched portion 12 is matched with the second matching portion 34, the abutting portion 32 on the switching element abuts against the protrusion 41. By providing the protrusion, the protruding portion has a certain elasticity, which helps the first matching portion and the second matching portion of the switching element to engage with the matched portion when the abutting portion contacts the protruding component, and prevents the switching element from being too rigid and not being able to engage in place when there is a size difference.

[0071] The base 2 is arranged at one end of the housing 1 away from the switching element, and the housing 1 is provided with notches 16 on both sides of the end away from the switching element, and a first clamping portion is provided in the middle of the end of the housing away from the switching element, and two opposite sides of the base 2 are respectively provided with a step portion 21 adapted to the notch, and a second clamping portion 22 adapted to the first clamping portion is provided on the base 2. The notch and the step portion cooperate to play a limiting role, and the clamping is achieved by the cooperation between the first clamping portion and the second clamping portion.

[0072] like Figures 4 to 7 , which is the cyclic working state of the utility model of a temperature fuse capable of repeated reflow soldering.

[0073] like Figure 4When the repeatable reflow soldering temperature fuse needs to be installed on the printed circuit board for the first time, the button is turned to the welding state, so that the welding limit groove and the limit block are engaged (that is, the second matching part and the first matched part are matched); at this time, the abutting part abuts against the spring leaf, that is, the spring leaf is in the prohibited state.

[0074] like Figure 5 After the welding is completed, the button is pushed until the working limit groove is engaged with the limit block (ie, the first matching portion is matched with the first matched portion). At this time, the abutting portion is separated from the reed, that is, the reed is in a working state.

[0075] like Figure 6 When the temperature sensing element reaches the preset protection temperature, the temperature sensing element melts, triggering the protection, and the reed separates from the electrode piece b.

[0076] like Figure 7 When it is necessary to repeat the welding again, the button is turned to the welding state again, so that the welding limit groove and the limit block are engaged again; at this time, the reed sheet contacts the electrode sheet b again, and after reflow welding, the reed sheet and the electrode sheet b are solidified and connected again through the temperature sensing element.

[0077] Please refer to Figures 1 to 7 , Embodiment 2 of the present utility model is:

[0078] The difference from the first embodiment is that the first matching portion is abutting portion, that is, the first matching portion is used as abutting portion, which not only has abutting effect on the metal elastic member, but also has a matching effect with the matched portion, thereby achieving a simplified structure.

[0079] Please refer to Figures 1 to 7 , Embodiment 3 of the present utility model is:

[0080] The difference from the first embodiment is that the first matched portion is the inner side wall of the housing close to the abutting portion, and the abutting portion is interference-fitted with the inner side wall of the housing close to the abutting portion. The limiting function is achieved by the abutting portion directly having an interference fit with the first matched portion.

[0081] Please refer to Figures 1 to 7 , the fourth embodiment of the utility model is:

[0082] The difference from the above-mentioned embodiment 1 is that: the matched part includes a first matched part, a second matched part and a third matched part; when the first matched part matches with the first matching part, the abutting part on the switching element does not abut against the other end of the metal elastic part, and the third matching part matches with the third matched part so that the third matching part does not abut against the metal elastic part; when the second matched part matches with the second matching part, the abutting part on the switching element abuts against the other end of the metal elastic part. By further adding the third matching part to match with the third matched part, the third matching part can be limited, which is equivalent to a secondary limiting effect on the switching element, effectively preventing the metal elastic part from being affected.

[0083] In summary, the utility model provides a repeatable reflow soldering temperature fuse, which increases a switching element, and is provided with a supporting portion for abutting against the other end of the metal elastic member, and a first matching portion and a second matching portion respectively corresponding to the first position and the second matching portion corresponding to the second position on the switching element, wherein the first matching portion and the second matching portion are both used to match with the matched portion to realize the switching function of the switching element, and at the same time, since the switching element is provided with a supporting portion for abutting against the other end of the metal elastic member, that is, the switching between abutting and non-abutting against the other end of the metal elastic member is realized, when the repeatable reflow soldering temperature fuse is installed on the printed circuit to be soldered, it needs to be set to a soldering state to prevent the repeatable reflow soldering temperature fuse from activating the over-temperature protection function, so that the supporting portion abuts against the other end of the metal elastic member; after soldering is completed, it needs to be set to a working state so that the supporting portion does not abut against the other end of the metal elastic member to exert its thermal protection function. When it needs to be used again and soldering is required, it can be set to a soldering state again. The utility model can be applied to printed circuits, household appliances, lighting, automobiles, heaters, reflow soldering, wave soldering, and manual soldering to overcome and minimize the quality loss caused by soldering.

[0084] The above description is only an embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent transformations made using the contents of the specification and drawings of the present invention, or directly or indirectly applied in the relevant technical field, are also included in the patent protection scope of the present invention.

Claims

1. A reflowable thermal fuse, comprising at least two electrodes and a metal elastic member for connecting the two electrodes, wherein one end of the metal elastic member is connected to one electrode, and the other end of the metal elastic member is connected to the other electrode through a temperature sensing element, characterized in that: It also includes a switching element, which is provided with a supporting portion for abutting against the other end of the metal elastic member, and a first matching portion corresponding to the first position and a second matching portion corresponding to the second position, and the first matching portion and the second matching portion both match with the matched portion.

2. A reflowable thermal fuse according to claim 1, characterized in that: The mated portion includes a first mated portion. When the first mated portion is mated with the first mating portion, the abutting portion on the switching element does not abut against the other end of the metal elastic part; when the first mated portion is mated with the second mating portion, the abutting portion on the switching element abuts against the other end of the metal elastic part.

3. A reflowable thermal fuse according to claim 2, characterized in that: The switching element is also provided with a third matching portion corresponding to the third position, and the matched portion also includes a third matched portion; when the first matched portion is matched with the first matching portion, the abutting portion on the switching element does not abut against the other end of the metal elastic part, and the third matching portion is matched with the third matched portion so that the third matching portion does not abut against the metal elastic part; when the first matched portion is matched with the second matching portion, the abutting portion on the switching element abuts against the other end of the metal elastic part.

4. The reflowable thermal fuse according to claim 1, characterized in that: The engaged portion includes a first engaged portion and a second engaged portion; when the first engaged portion is engaged with the first engaging portion, the abutting portion on the switching element does not abut against the other end of the metal elastic part; when the second engaged portion is engaged with the second engaging portion, the abutting portion on the switching element abuts against the other end of the metal elastic part.

5. A reflowable thermal fuse according to claim 4, characterized in that: The switching element is also provided with a third matching portion corresponding to the third position, and the matched portion also includes a third matched portion; when the first matched portion is matched with the first matching portion, the abutting portion on the switching element does not abut against the other end of the metal elastic part, and the third matching portion is matched with the third matched portion so that the third matching portion does not abut against the metal elastic part; when the second matched portion is matched with the second matching portion, the abutting portion on the switching element abuts against the other end of the metal elastic part.

6. A reflowable thermal fuse according to claim 2 or 4, characterized in that: The first matching portion is abutting portion.

7. A reflowable thermal fuse according to claim 2 or 4, characterized in that: It also includes a shell, the first matched portion is an inner side wall of the shell close to the abutting portion, and the abutting portion is interference-fitted with the inner side wall of the shell close to the abutting portion.

8. The reflowable thermal fuse according to claim 1, characterized in that: It also includes a shell, the shell is provided with a first mounting portion, the switching element is provided with a second mounting portion matched with the first mounting portion, and the matched portion is provided on the shell.

9. The reflowable thermal fuse according to claim 8, characterized in that: An extension portion is arranged on the inner side wall of the shell, and the matched portion is arranged at the free end of the extension portion.

10. The reflowable thermal fuse according to claim 8, characterized in that: The first mounting portion is a through hole provided on two opposite side walls of the housing, and the second mounting portion is a rotating shaft provided on two opposite side walls of the switching element. The rotating shaft passes through the through hole so that the switching element can be rotatably provided on the housing.

11. The reflowable thermal fuse according to claim 8, characterized in that: A guide groove is arranged on the inner side wall of the shell, and a guide step matched with the guide groove is arranged on the outer side wall of the switching element.

12. The reflowable thermal fuse according to claim 1, characterized in that: The first matching portion and the second matching portion are both limiting grooves, and the matched portion is a limiting protrusion.

13. The reflowable thermal fuse according to claim 1, characterized in that: A protruding portion is provided at the other end of the metal elastic member, and when the matched portion is matched with the second matching portion, the abutting portion on the switching element abuts against the protruding portion.

14. The reflowable thermal fuse according to claim 8, characterized in that: It also includes a base, which is arranged at one end of the shell away from the switching element, and notches are arranged on both sides of the end of the shell away from the switching element. A first clamping portion is arranged in the middle position of the end of the shell away from the switching element, and a step portion adapted to the notch is respectively arranged on opposite sides of the base, and a second clamping portion adapted to the first clamping portion is arranged on the base.

Images