Opening and closing structure for excitation fuse and excitation fuse with opening and closing structure

Abstract

The invention relates to an on-off structure for an excitation fuse and the excitation fuse with the on-off structure. The excitation fuse comprises an insulating shell internally provided with a mounting cavity, the breaking structure comprises a plurality of breaking electrodes, the breaking electrodes transversely penetrate through the insulating shell, the section, located in the mounting cavity, of each breaking electrode is provided with a thinned easily-broken part, and each easily-broken part is provided with a guide hole extending in the thickness direction; the plurality of cut-off grid sheets are movably mounted in the mounting cavity and are respectively arranged opposite to the easy-to-break parts, the end surface, adjacent to the corresponding easy-to-break part, of each cut-off grid sheet is provided with a guide part section extending towards the corresponding easy-to-break part, and the shape of the end surface of each cut-off grid sheet is matched with that of the corresponding easy-to-break part; and the shape of the end surface of each guide section is matched with the corresponding guide hole, so that when the plurality of cut-off grid sheets are forced to move to the corresponding cut-off electrodes, each guide section is guided to an expected orientation through the corresponding guide hole, and the end surfaces of the plurality of cut-off grid sheets synchronously cut off the corresponding easily-broken parts.

Description

Technical Field

[0001] The present invention relates to the technical field of switchgear, and in particular to a breaking structure for an excitation fuse and an excitation fuse having the same. Background Art

[0002] Excitation fuses or smart fuses are widely used as short-circuit current and overcurrent protectors in various types of power distribution systems and control system electrical equipment, especially for semiconductor rectifier elements or rectifier devices. The excitation fuse can be connected in series to the protected circuit and can include multiple breaking grids and multiple breaking electrodes opposite to the breaking grids. When any phase of the protected circuit fails, each breaking grid can be driven to cut off the corresponding breaking electrode, thereby disconnecting the circuit to achieve the purpose of protecting the circuit. However, due to the unavoidable machining errors and installation errors between the breaking grids and the corresponding breaking electrodes of each phase of the excitation fuse in the prior art, such as the two-phase excitation fuse or the three-phase excitation fuse, the breaking grids of each phase will unbalancedly cut off the corresponding breaking electrode during the breaking period, resulting in the problem that the breaking electrode of a certain phase will be cut off first and the remaining phases will be cut off later or even cannot be cut off, thereby causing the defect of low reliability of the excitation fuse.

[0003] Therefore, there is a demand in the art for a breaking structure with balanced force and high reliability and an excitation fuse having the breaking structure. Summary of the invention

[0004] The present invention aims to provide a disconnect structure which can at least solve some of the above problems.

[0005] The present invention also aims to provide an excitation fuse using the above improved breaking structure.

[0006] According to one aspect of the present invention, there is provided a breaking structure for an excitation fuse, the excitation fuse comprising an insulating shell with an installation cavity therein, the breaking structure comprising: a plurality of breaking electrodes, which cross the insulating shell and whose sections located in the installation cavity are all provided with thinned easy-to-break portions, each of which is provided with a guide hole extending in the thickness direction; a plurality of breaking grids, which are movably installed in the installation cavity and are respectively arranged opposite to each of the easy-to-break portions, each breaking grid is provided with a guide section extending toward the corresponding easy-to-break portion on the end face adjacent to the corresponding easy-to-break portion, the end face shape of each breaking grid is adapted to the corresponding easy-to-break portion, and the end face shape of each guide section is adapted to the corresponding guide hole, so that when the plurality of breaking grids are forced to move toward the corresponding breaking electrodes, each guide section is guided to a desired orientation through the corresponding guide hole, so that the end faces of the plurality of breaking grids synchronously cut off the corresponding easy-to-break portions.

[0007] Compared with the prior art, the breaking structure of the excitation fuse in the present invention can cut off the protected circuit when the protected circuit fails through the mutually coordinated breaking electrodes and breaking grids of each phase, thereby reliably protecting the protected circuit. In addition, the breaking structure can correct the breaking grids of each phase to the same desired orientation through the cooperation of the guiding sections and the guiding holes before the breaking grids cut off the breaking electrodes, so that the breaking grids of each phase can synchronously cut off the corresponding breaking grids in the desired orientation, with balanced force and reliable breaking, avoiding the asynchronous cutting of the corresponding breaking electrodes by the breaking grids of each phase due to installation and processing mechanical errors.

[0008] Preferably, the plurality of breaking grids are designed to be cylindrical, and the shape of each of the breakable portions is designed to be circular to fit the end surface of the corresponding breaking grid. In this way, the breaking structure of the present invention can greatly enhance strength in a limited space.

[0009] Preferably, each of the guide sections is designed to be cylindrical, and the shape of each of the guide holes is designed to be circular to fit the end surface of the corresponding guide section. In this way, the breaking structure of the present invention can guide the guide section and thus the breaking grid in all directions on the transverse plane, and can reduce the use of injection molding materials, thereby reducing costs.

[0010] Preferably, each of the breakable portions is formed by providing a groove on a side of the corresponding breaking electrode away from the corresponding breaking grid.

[0011] According to another aspect of the present invention, an excitation fuse is also provided, which includes an insulating shell and a breaking structure according to any one of claims 1 to 4, the insulating shell includes a first shell and a second shell that are butted against each other to cooperate to form the installation cavity, the multiple breaking electrodes extend from between the first shell and the second shell, and the multiple breaking grids are installed in the first shell.

[0012] Preferably, the excitation fuse further comprises a force-bearing portion attached to the end sides of the plurality of breaking grids away from the plurality of breaking electrodes.

[0013] Preferably, the excitation fuse also includes a first pressure plate clamped between the first shell and the breaking electrode, and a first limiting portion extending toward the force-bearing portion to abut against the peripheral side of the force-bearing portion is formed on the side of the first pressure plate facing the first shell.

[0014] Preferably, a first mounting portion protruding toward the first pressing plate is formed on an end side of the first shell facing the first pressing plate, and a first recess for accommodating the first mounting portion is provided on a side of the first pressing plate facing the first shell.

[0015] Preferably, the excitation fuse also includes a second pressure plate clamped between the multiple breaking electrodes and the second shell, and the second pressure plate is provided with a second limiting portion extending in contact with the inner side of the second shell on the side facing the second shell; and the first pressure plate is formed with a positioning portion extending through each breaking electrode and extending into the second pressure plate on the side facing the multiple breaking electrodes.

[0016] Preferably, a second mounting portion protruding toward the second shell is further provided on a side of the second pressure plate facing the second shell, and a second recess for accommodating the second mounting portion is provided on an end side of the second shell facing the second pressure plate.

[0017] Some of the other features and advantages of the present invention will be apparent to those skilled in the art after reading this application, and the other parts will be described in the following specific embodiments in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The embodiments of the present invention are described in detail below with reference to the accompanying drawings, wherein:

[0019] Figure 1 is a cross-sectional view of a fuse according to the present invention;

[0020] Figure 2 is a cross-sectional view of the breaking structure of the fuse according to the present invention.

[0021] Description of reference numerals:

[0022] 100-excitation fuse; 10-breaking structure; 11-breaking electrode; 111-easy-to-break part; 112-guide hole; 12-breaking grid; 121-guide section; 122-force-bearing part; 20-insulating shell; 21-first shell; 211-first mounting part; 22-second shell; 23-mounting cavity; 30-first pressure plate; 32-first limiting part; 33-positioning part; 40-second pressure plate; 41-second mounting part; 42-second limiting part; 50-upper chamber assembly; 51-gas generating device; 52-connector; 60-bushing; 70-lower chamber assembly. DETAILED DESCRIPTION

[0023] Now, with reference to the accompanying drawings, the schematic scheme of the excitation fuse and its breaking structure disclosed in the present invention is described in detail. Although the drawings are provided to present some embodiments of the present invention, the drawings do not have to be drawn according to the size of the specific implementation scheme, and certain features may be enlarged, removed or partially cut to better illustrate and explain the disclosure of the present invention. Some components in the drawings can be adjusted in position according to actual needs without affecting the technical effect. The phrase "in the drawings" or similar terms appearing in the specification do not necessarily refer to all drawings or examples.

[0024] Certain directional terms used to describe the drawings below, such as "inside", "outside", "above", "below" and other directional terms, will be understood to have their normal meanings and refer to those directions involved when the drawings are normally viewed. Unless otherwise specified, the directional terms described in this specification are basically in accordance with the conventional directions understood by those skilled in the art.

[0025] The terms "first", "first", "second", "second" and the like used in the present invention do not indicate any order, quantity or importance, but are used to distinguish one component from other components.

[0026] The terms "joining", "connection" and the like as used in the present invention include both that two components are indirectly connected together by means of an intermediate layer such as an adhesive, a welding agent, etc. or an intermediate piece such as a connector, a transition piece, etc., and that two components are directly connected together without the aid of any intermediate layer such as an adhesive, a welding agent, etc. or an intermediate piece such as a connector, a transition piece, etc.

[0027] Figure 1 to Figure 2 The excitation fuse 100 and its breaking structure 10 of the present invention are shown by way of example. The breaking structure 10 of the excitation fuse 100 in this example can simultaneously cut off each phase circuit when a fault occurs in the protected circuit, thereby greatly improving the reliability of the excitation fuse 100. As shown in the figure, the excitation fuse 100 may include an insulating housing 20 and a breaking structure 10.

[0028] Specifically, the insulating housing 20 is provided with a mounting cavity 23 inside and may include a first housing 21 and a second housing 22. The first housing 21 may be a cavity structure with openings at both ends, and the second housing 22 may be a cavity structure with an opening at the upper end and a closed lower end, so that the lower port of the first housing 21 may be aligned with the upper port of the second housing 22 and may be connected to the second housing 22 by connecting screws, so that the first housing 21 may cooperate with the cavity of the second housing 22 to form the mounting cavity 23. The partial connection between the first housing 21 and the second housing 22 may cooperate to form an opening that communicates with the internal mounting cavity 23, so that the breaking mechanism located in the mounting cavity 23 may pass through it.

[0029] The breaking structure 10 may include a plurality of breaking electrodes 11 and a plurality of breaking grids 12. Those skilled in the art should understand that, for a two-phase excitation fuse, the breaking structure 10 may include two breaking electrodes 11 and two breaking grids 12 opposite thereto, and for a three-phase excitation fuse, the breaking structure 10 may include three breaking electrodes 11 and three breaking grids 12 opposite thereto. Exemplarily, the breaking electrode 11 may be a straight copper bar, and the plurality of breaking electrodes 11 may be arranged in a transverse plane, i.e., perpendicular to the horizontal plane. Figure 1The plurality of disconnecting grids 12 are arranged spaced apart from each other on the plane of the page where the drawing is located, and correspondingly, the plurality of disconnecting grids 12 can be opposite to the plurality of disconnecting electrodes 11 in the mounting cavity 23 one by one. Figure 1 and Figure 2 The view is a longitudinal section, so Figure 1 and Figure 2 Only one interrupting electrode 11 and one interrupting grid 12 are shown.

[0030] A plurality of breaking electrodes 11 may be clamped between the first shell 21 and the second shell 22, and both ends of each breaking electrode may extend from between the first shell 21 and the second shell 22 to be connected to each phase circuit. An easy-to-break portion 111 may be provided at the end of the breaking electrode located in the mounting cavity 23. The easy-to-break portion 111 is thinner than other portions of the breaking electrode so that it can be broken under the impact of the corresponding breaking grid 12. The breaking electrode 11 is cut into two parts at the easy-to-break portion 111, thereby disconnecting the circuit of the corresponding phase. The breaking grid 12 may be slidably mounted in the mounting cavity 23 and located above the corresponding breaking electrode 11, so that when the breaking grid 12 is forced to move, it impacts the easy-to-break portion 111 with the help of gravity.

[0031] The easy-to-break portion 111 of the breaking electrode 11 may be provided with a guide hole 112 which penetrates the easy-to-break portion 111 along the thickness direction. Accordingly, a portion of the end surface of the breaking grid 12 adjacent to the easy-to-break portion 111, i.e., the lower end surface, such as a roughly central portion, may extend toward the easy-to-break portion 111, i.e., extend downward to form a guide section 121. The dimension of the guide section 121 in a direction transverse to its extension direction, i.e., the lateral dimension, may be smaller than that of the grid. Thus, when the multiple breaking grids 12 are forced to move toward the multiple breaking electrodes 11, the guide sections 121 of each breaking grid 12 first pass through the corresponding guide holes 112 of adapted shape, so that the multiple breaking grids 12 that are not in the desired same orientation due to mechanical errors, installation errors, and uneven forces, for example, a portion of the breaking grids 12 is tilted relative to other breaking grids 12, etc., can be corrected to the desired vertical state due to their respective guide sections 121 passing through the corresponding guide holes 112, and the corresponding breaking grids 12 adjacent to each guide section 121 can thereby synchronously act on the corresponding easy-to-break portion 111, so that the multiple breaking grids 12 can synchronously cut off the corresponding breaking grids 12.

[0032] Optionally, the plurality of breaking grids 12 and the guide sections 121 extending from each breaking grid 12 can be designed as a cylindrical shape, which has a higher strength than a rectangular sheet shape and can avoid occupying space. Thus, the shape of the easy-to-break portion 111 corresponding to each breaking grid 12 can be designed as an adaptive circle, and the shape of the guide hole 112 corresponding to each guide section 121 can also be designed as an adaptive circle. Exemplarily, the diameter of the breaking grid 12 and the diameter of the easy-to-break portion 111 can be 4 mm to 10 mm, the diameter of the guide section 121 and the diameter of the guide hole 112 can be 2 mm to 4 mm, and the thickness of the breaking electrode 11 can be 0.5 mm to 1 mm.

[0033] Optionally, the breaking electrode 11 may be provided with a groove on the upper surface or the lower surface of a substantially central section located in the mounting cavity 23 to form a thinned easy-to-break portion 111. Figure 1 and Figure 2 As shown, the fragile portion 111 is formed by providing a groove on the lower surface of the breaking electrode 11. Compared with providing a groove on the upper surface of the breaking electrode 11, the fragile portion 111 can be closer to the breaking grid 12 located above the fragile portion 111, so as to act on the breaking electrode 11 before the impact of the breaking grid 12 is further weakened. In addition to providing a groove with the same shape as the fragile portion 111 on the surface of the breaking electrode 11, a V-shaped groove or other conceivable shapes can also be provided in the area corresponding to the fragile portion 111 on the surface of the breaking electrode 11.

[0034] Optionally, the upper side of the plurality of breaking grids 12 is provided with a force-bearing portion 122 attached thereto, and the upper side of the force-bearing portion 122 is provided with an upper chamber assembly 50, such as a gas generating device 51 such as an explosive device that can be attached to the upper side of the force-bearing portion 122, and a connector 52 connected to the gas generating device 51 at the upper end of the first shell 21, i.e., above the gas generating device 51. Thus, the connector 52 can receive an external breaking signal and send the signal to the gas generating device 51, and the gas generating device 51 ejects gas according to the signal to push the force-bearing portion 122 and then push the plurality of breaking grids 12 to move downward. It can be understood that the ejected gas cannot act completely evenly on the force-bearing portion 122, so the breaking structure 10 in the present invention can make each breaking grid 12 in a desired orientation when the breaking electrode 11 is about to be cut off by means of the mutually cooperating guide sections 121 and guide holes 112.

[0035] Alternatively, if Figure 1As shown, the excitation fuse 100 may also include a first pressing plate 30 clamped between the first housing 21 and the breaking electrode 11 and a second pressing plate 40 clamped between the breaking electrode 11 and the second housing 22. With the help of the first pressing plate 30 and the second pressing plate 40, not only the breaking electrode 11 can be better clamped, but also the movement of the breaking grid 12 toward the breaking motor can be guided. The portion of the first pressing plate 30 corresponding to the fragile portion 111 may be provided with a through hole of a shape-matched shape to allow and guide the breaking grid 12 to pass therethrough. The portion of the second pressing plate 40 corresponding to the fragile portion 111 may be provided with a through hole with a diameter slightly larger than the diameter of the fragile portion 111, which is not only used for the breaking grid 12 to pass through after cutting off the breaking electrode 11, but also can accommodate the fragile portion 111 carried downward due to the breaking grid 12 cutting off the breaking electrode 11.

[0036] The excitation fuse 100 may also include a bushing 60, such as a stainless steel bushing 60, which surrounds the gas generating device 51 and the upper part of the peripheral side of the force-bearing part 122 on the inner side of the first shell 21. The upper side of the first pressure plate 30 may be provided with a first limiting portion 32 extending upward along the inner side of the first shell 21 to the lower part of the peripheral side of the force-bearing part 122 and abutting against the lower end of the bushing 60. The bushing 60 is in close contact with the first limiting portion 32, thereby forming a path to guide the gas flow and avoiding the weakening of the thrust on the force-bearing part 122 due to gas overflow.

[0037] A first recess may be provided on the upper side of the first pressure plate 30 in an area relative to the first shell body 21, and a first mounting portion 211 is correspondingly formed on the lower side of the first shell body 21. The shapes of the first mounting portion 211 and the first recess are adapted so that the first mounting portion 211 can be accommodated in the first recess, and the first mounting portion 211 extends downward relative to the first limiting portion 32 through the junction between the first mounting portion 211 and the first recess, thereby further extending the flow path of the gas that leaks undesirably from the junction between the bushing 60 and the first limiting portion 32 between the first limiting portion 32 and the first shell body 21, thereby further improving the sealing effect.

[0038] The lower side of the first pressing plate 30 may be provided with a positioning portion 33 extending downward through each breaking electrode 11 to the second pressing plate 40. The positioning portion 33 may be located on the first pressing plate 30 on both sides relative to the breaking grid 12. On the one hand, it can facilitate the positioning and installation between the first pressing plate 30, the breaking electrode 11 and the second pressing plate 40. On the other hand, the joints between the positioning portion 33 and the breaking electrode 11 and the second pressing plate 40 extend downward relative to the first pressing plate 30, which can further extend the flow path of the gas that leaks undesirably from the joints between the first pressing plate 30 and the breaking electrode 11 and the joints between the breaking electrode 11 and the second pressing plate 40, thereby further improving the sealing effect.

[0039] Similar to the cooperation between the first mounting portion 211 of the first shell 21 and the first recess of the first pressing plate 30, the lower side of the second pressing plate 40 may also form a downwardly protruding second mounting portion 41, and the upper end side of the second shell 22 may be provided with a second recess for accommodating the second mounting portion 41. The second mounting portion 41 and the second recess are tightly matched and extend downward relative to the second pressing plate 40, and can also be used to extend the flow path of the gas that is not expected to leak. The lower side of the second pressing plate 40 may also be provided with a second limiting portion 42 extending from the inner side of the second shell 22, and the downward extension length of the second limiting portion 42 is much greater than the second mounting portion 41, so as to extend the flow path of the gas that is not expected to leak from the junction between the second pressing plate 40 and the lower chamber assembly 70 located on the inner side of the second shell 22, so as to further improve the sealing effect.

[0040] It can be seen that the first mounting portion 211 of the first shell 21, the first recessed portion of the first pressure plate 30, the first limiting portion 32 of the first pressure plate 30, the positioning portion 33 of the first pressure plate 30, the second mounting portion 41 of the second pressure plate 40, the second limiting portion 42 of the second pressure plate 40 and the second recessed portion of the second shell 22 cooperate to form a labyrinth sealing structure similar to that to minimize the leakage of the gas ejected by the gas generating device 51, thereby ensuring the pushing effect on the multiple breaking grids 12.

[0041] Optionally, the lower chamber assembly 70 in the second housing 22 may include an extension hole relative to the fragile portion 111 to allow the breaking grid 12 to move further after cutting the fragile portion 111. The lower chamber assembly 70 may also include a structure such as a wire mesh in the extension hole to reduce the arc temperature.

[0042] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0043] The above description is only an illustrative embodiment of the present invention and is not intended to limit the scope of the present invention. Any equivalent changes, modifications and combinations made by any person skilled in the art without departing from the concept and principle of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A breaking structure (10) for an excitation fuse (100), the excitation fuse (100) comprising an insulating housing with a mounting cavity (23) therein, characterized in that: The breaking structure (10) comprises: A plurality of breaking electrodes (11), each of which crosses the insulating housing and is located in the mounting cavity (23) and is provided with a thinned breakable portion (111), and each of the breakable portions (111) is provided with a guide hole (112) extending in the thickness direction; A plurality of breaking grids (12) are movably mounted in the mounting cavity (23) and are respectively arranged opposite to the respective easy-to-break portions (111); the end surface of each breaking grid (12) adjacent to the corresponding easy-to-break portion (111) is provided with a guide section (121) extending toward the corresponding easy-to-break portion (111); the end surface shape of each breaking grid (12) is adapted to the corresponding easy-to-break portion (111); the end surface shape of each guiding section (121) is adapted to the corresponding guiding hole (112), so that when the plurality of breaking grids (12) are forced to move toward the corresponding breaking electrode (11), each guiding section (121) is guided to a desired orientation through the corresponding guiding hole (112), so that the end surfaces of the plurality of breaking grids (12) synchronously cut off the corresponding easy-to-break portion (111).

2. The breaking structure (10) for exciting a fuse (100) according to claim 1, characterized in that: The plurality of breaking grids (12) are all designed to be cylindrical in shape, and the shape of each of the easy-to-break portions (111) is designed to be circular and adapted to the end surface of the corresponding breaking grid (12).

3. The breaking structure (10) for exciting a fuse (100) according to claim 1 or 2, characterized in that: Each of the guide sections (121) is designed to be in a cylindrical shape, and the shape of each of the guide holes (112) is designed to be circular and adapted to the end surface of the corresponding guide section (121).

4. The breaking structure (10) for exciting a fuse (100) according to claim 1, characterized in that: Each of the easy-to-break portions (111) is formed by providing a groove on a side of the corresponding breaking electrode (11) that is away from the corresponding breaking grid (12).

5. An excitation fuse (100), characterized in that: The excitation fuse (100) comprises an insulating shell and a breaking structure (10) according to any one of claims 1 to 4, the insulating shell comprising a first shell (21) and a second shell (22) which are butted against each other to cooperate to form the installation cavity (23), the plurality of breaking electrodes (11) extend from between the first shell (21) and the second shell (22), and the plurality of breaking grids (12) are installed in the first shell (21).

6. The excitation fuse (100) according to claim 5, characterized in that: The energizing fuse (100) further comprises a force receiving portion (122) attached to the end sides of the plurality of breaking grids (12) away from the plurality of breaking electrodes (11).

7. The excitation fuse (100) according to claim 6, characterized in that: The excitation fuse (100) further comprises a first pressing plate (30) clamped between the first shell (21) and the breaking electrode (11), and a first limiting portion (32) extending toward the force-bearing portion (122) to abut against the peripheral side of the force-bearing portion (122) is formed on a side of the first pressing plate (30) facing the first shell (21).

8. The excitation fuse (100) according to claim 7, characterized in that: A first mounting portion (211) protruding toward the first pressing plate (30) is formed on the end side of the first shell (21) facing the first pressing plate (30), and a first recessed portion for accommodating the first mounting portion (211) is provided on one side of the first pressing plate (30) facing the first shell (21).

9. The excitation fuse (100) according to claim 8, characterized in that: The excitation fuse (100) further comprises a second pressing plate (40) clamped between the plurality of breaking electrodes (11) and the second shell (22); a second limiting portion (42) extending in contact with the inner side of the second shell (22) is provided on a side of the second pressing plate (40) facing the second shell (22); A positioning portion (33) is formed on one side of the first pressing plate (30) facing the plurality of breaking electrodes (11), the positioning portion extending through each breaking electrode (11) and extending into the second pressing plate (40).

10. The excitation fuse (100) according to claim 9, characterized in that: A second mounting portion (41) protruding toward the second shell (22) is also provided on the side of the second pressure plate (40) facing the second shell (22), and a second recessed portion for accommodating the second mounting portion (41) is provided on the end side of the second shell (22) facing the second pressure plate (40).

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