CN118538583A - Drop-out current limiting fuse - Google Patents

Abstract

The present application relates to a drop-type current-limiting fuse, and relates to the technical field of fuses, which comprises a fusion tube and an insulating porcelain bottle, wherein an upper conductive sleeve and a lower conductive sleeve are fixedly provided at both ends of the fusion tube, a connecting frame is hinged on the outer periphery of the lower conductive sleeve, and a fixed shaft is fixedly provided on the connecting frame; an upper bracket and a lower bracket are fixedly provided at both ends of the insulating porcelain bottle, a static contact piece abutting against the upper conductive sleeve is fixedly provided on the upper bracket, and a placement notch for inserting the fixed shaft is provided on the lower bracket; a locking piece for locking the fixed shaft is hinged on the outer periphery of the lower conductive sleeve, an insulating push rod and a fuse wound on the insulating push rod are provided inside the fusion tube, and the two ends of the fuse are respectively connected with the upper conductive sleeve and the lower conductive sleeve, a reset piece in a compressed state is provided between the insulating push rod and the upper conductive sleeve, and a locking through hole is provided on the lower conductive sleeve; since the fuse is installed inside the fusion tube, the influence of the external environment on the fuse is greatly reduced.

Description

A drop-out current-limiting fuse

Technical Field

The present application relates to the technical field of fuses, and in particular to a drop-out current-limiting fuse.

Background Art

A drop-out fuse is an electrical device that is mainly used to automatically disconnect the circuit to protect electrical equipment and personnel. This type of fuse was originally widely used in power systems, and with the development of technology, it has also been used in UPS (uninterruptible power supply) and cloud computing architecture. Through its unique principle and structure, the drop-out fuse can quickly disconnect the circuit when an overload or short circuit occurs in the circuit, thereby protecting the stability and safety of the system.

In the power system, the drop-out fuse is a vital protection device. It ensures the safe operation of the circuit through a unique structure, such as an insulating porcelain bottle, a fuse tube and an operating mechanism. Among them, the fuse installed inside the fuse tube is closely connected to the upper moving contact and the lower moving contact at both ends to form a closed circuit of the circuit. The upper and lower ends of the insulating porcelain bottle are respectively fixed with an upper wiring board and a lower wiring board. The upper wiring board is provided with a static contact piece that is in close contact with the upper moving contact at the upper end of the fuse tube, while the lower moving contact is rotatably connected to the upper hinged plate. When an abnormal situation such as overload or short circuit occurs in the circuit, the current will increase rapidly, exceeding the load limit of the fuse, causing the fuse to melt, thereby cutting off the circuit; after the fuse melts, the tension originally generated by it on the upper and lower moving contacts disappears, causing the upper moving contact to separate from the static contact piece.

Before using the drop-out fuse, a series of tedious manual operations are required to wind and fix the lower end of the fuse on the lower terminal board, and then adjust the lower moving contact and the fuse tube to a tensioned state; however, in actual operation, it is easily disturbed by external factors. In particular, when encountering external forces, vibrations or strong winds, the connection between the fuse and the lower terminal board may become loose, causing the tension state of the lower moving contact and the fuse tube to be destroyed, thereby affecting the normal operation and protection effect of the fuse, and there is room for improvement.

Summary of the invention

The purpose of the present application is to provide a drop-type current-limiting fuse to solve the problem that the harsh external environment has a significant impact on the connection between the fuse and the lower terminal board, which may cause the tension state of the lower moving contact and the fuse tube to be destroyed.

The present application provides a drop-out current-limiting fuse that adopts the following technical solution:

A drop-type current-limiting fuse comprises a melting tube and an insulating porcelain bottle, wherein an upper conductive sleeve and a lower conductive sleeve are fixedly provided at both ends of the melting tube, a connecting frame is hinged on the outer circumference of the lower conductive sleeve, and a fixed shaft is fixed on the connecting frame; an upper bracket and a lower bracket are fixedly provided at both ends of the insulating porcelain bottle, a static contact piece abutting against the upper conductive sleeve is fixedly provided on the upper bracket, and a placement notch for inserting the fixed shaft is provided on the lower bracket; a locking piece for locking the fixed shaft is hinged on the outer circumference of the lower conductive sleeve, an insulating push rod and a fuse wound on the insulating push rod are provided inside the melting tube, and the two ends of the fuse are respectively connected with the upper conductive sleeve and the lower conductive sleeve, a reset piece in a compressed state is provided between the insulating push rod and the upper conductive sleeve, and a locking through hole is provided on the lower conductive sleeve; after the fuse is broken, under the action of the reset piece, the lower end portion of the insulating push rod can pass through the locking through hole and release the locking of the fixed shaft by the locking piece.

By adopting the above technical solution, when the fuse is normally used under normal conditions, the fuse is placed at an angle. When the fuse breaks, the circuit connected to the fuse is disconnected, and the reset member in the compressed state is reset, thereby squeezing the insulating push rod, so that the lower end of the insulating push rod passes through the locking through hole and can release the locking of the fixed shaft by the locking member. At this time, the fuse tube falls rapidly because the locking member unlocks the fixed shaft, forming an obvious disconnection position; since the fuse is installed inside the fuse tube and does not extend to the outside to be connected and fixed to the lower bracket, the influence of the external environment on the fuse is greatly reduced.

Optionally, the locking member is a separation hook hinged on the outer periphery of the lower conductive sleeve through a rotating shaft, one end of the separation hook is fixed with an abutment plate located below the locking through hole, and the rotating shaft is sleeved with a torsion spring for making the separation hook buckle on the outer periphery of the fixed shaft.

By adopting the above technical solution, due to the setting of the separation hook, when the line connected to the fuse operates normally, the separation hook is tightly fastened on the outer periphery of the fixed shaft under the torsion force of the torsion spring; when a fault occurs in the line, the fuse breaks, the reset member in the compressed state resets and squeezes the insulating push rod, so that the lower end of the insulating push rod passes through the locking through hole and squeezes the abutment plate, thereby releasing the lock of the fixed shaft by the separation hook. At this time, the fuse tube quickly falls down because the locking member unlocks the fixed shaft, forming an obvious disconnection position, thereby realizing the rapid action of the fuse tube on the fuse, and improving the performance of the fuse in application.

Optionally, the reset member includes a reset spring located between the upper conductive sleeve and the insulating push rod, and one end of the reset spring is fixed on the inner wall of the upper conductive sleeve.

By adopting the above technical solution, due to the installation arrangement of the reset spring, after the fuse breaks, the insulating push rod releases the squeezing of the reset spring. At this time, the reset spring resets, causing the reset spring to squeeze the upper end of the insulating push rod, thereby causing the lower end of the insulating push rod to pass through the locking through hole and release the locking piece from locking the fixed shaft.

Optionally, the reset member also includes an arc-shaped conductive block located outside the upper conductive sleeve and a positioning rod fixed on the arc-shaped conductive block, the upper conductive sleeve is provided with a positioning through hole for the positioning rod to pass through, a retaining ring is fixed on the outer periphery of the end of the positioning rod inserted into the upper conductive sleeve, and the reset spring is sleeved on the outer periphery of the telescopic rod and abuts against one side of the retaining ring.

By adopting the above technical solution, the reset spring is limited and fixed, and the stability of the static contact piece and the arc-shaped conductive block when they are in contact is improved; when the fuse breaks, the reset spring is reset, and then the arc-shaped conductive block is pulled away from the static contact piece through the positioning rod, so that the arc-shaped conductive block and the static contact piece are separated, which is convenient for the subsequent downward flipping of the fuse tube.

Optionally, a compression spring is sleeved on the outer circumference of the positioning rod, and a positioning recessed groove for inserting the end of the compression spring is formed on the outer opening edge of the positioning through hole.

By adopting the above technical solution, when the fuse breaks, the reset spring resets, and then the arc-shaped conductive block is pulled to move away from the static contact piece through the positioning rod, so that the compression spring is completely compressed into the positioning groove, and then the arc-shaped conductive block and the static contact piece are separated, which is convenient for the subsequent downward flipping of the fuse tube, thereby improving the performance of the fuse during application; due to the setting of the positioning groove, the lower end of the compression spring is limited, which reduces the possibility of the compression spring being offset or misplaced during application, thereby improving the installation stability of the compression spring.

Optionally, the fuse is provided with a plurality of narrow necks.

By adopting the above technical solution, when the current connected to the fuse is too large, the multiple narrow-necked fuses use the excessive current to pass through the multiple narrow necks, thereby melting the fuses at the same time. The current limiting action is obviously much faster than that of traditional fuses, thereby improving the performance of the fuse.

Optionally, a connecting protrusion is fixedly provided on the outer periphery of the lower conductive sleeve, an elastic conductive sheet is fixedly provided on the connecting protrusion, and a conductive protrusion capable of pressing tightly against the elastic conductive sheet is fixedly provided on the connecting frame.

By adopting the above technical solution, when the circuit to which the fuse is connected operates normally, in addition to the separation hook being tightly fastened to the outer periphery of the fixed shaft under the torsion force of the torsion spring, the elastic conductive sheet on the lower conductive sleeve abuts against the conductive protrusion on the connecting frame and can provide current transmission, thereby improving the stability during current transmission.

Optionally, a compression spring in a compressed state is fixedly disposed on a side surface of the upper bracket, and the other end of the compression spring is pressed against a side surface of the static contact piece away from the upper conductive sleeve.

By adopting the above technical solution, due to the setting of the extrusion spring, when the fuse is normally used, the static contact piece is pressed by the extrusion spring and pressed against the upper side of the upper conductive sleeve, thereby improving the stability of current transmission.

Optionally, a protrusion is provided on the side of the static contact piece away from the upper conductive sleeve, and a limiting groove is provided on the side of the protrusion facing the upper conductive sleeve for the end of the upper conductive sleeve away from the melting tube to be inserted into, and the end of the extrusion spring away from the upper bracket is sleeved on the outside of the protrusion.

By adopting the above technical solution, due to the setting of the protrusion and the limiting groove, the extrusion spring is limited by the protrusion, and the upper side surface of the upper conductive sleeve is also limited by the limiting groove, thereby improving the stability of the fuse during use.

Optionally, a plurality of reinforcing ridges are provided on the side of the static contact piece facing the upper conductive sleeve.

By adopting the above technical solution, the structural strength of the stationary contact piece is enhanced.

In summary, the present application includes at least one of the following beneficial technical effects:

1. Since the fuse is installed inside the fuse tube and does not extend to the outside to be connected and fixed with the lower bracket, the influence of the external environment on the fuse is greatly reduced, and the possibility of the tension state of the lower moving contact and the fuse tube being damaged is reduced.

2. Due to the arrangement of several narrow necks on the fuse, when the current connected to the fuse is too large, the fuses with multiple narrow necks use the excessive current to pass through the multiple narrow necks, thereby melting the fuses at the same time. The current limiting action is obviously much faster than that of the traditional fuse, thereby improving the performance of the fuse.

3. Due to the coordinated arrangement of the elastic conductive sheet and the conductive protrusion, when the circuit to which the fuse is connected operates normally, in addition to the separation hook being tightly fastened to the outer periphery of the fixed shaft under the torsion force of the torsion spring, the elastic conductive sheet on the lower conductive sleeve abuts against the conductive protrusion on the connecting frame and can provide current transmission, thereby improving the stability during current transmission.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

FIG1 is a schematic diagram of the overall structure of Example 1 of the present application;

FIG2 is a cross-sectional structural diagram of the installation and coordination of the fusion tube in Example 1 of the present application;

FIG3 is a schematic structural diagram of the narrow neck distribution on the fuse in Embodiment 1 of the present application;

FIG4 is a partial cross-sectional structural schematic diagram of the installation and matching of the static contact piece and the upper conductive sleeve in Embodiment 1 of the present application;

FIG5 is a partial cross-sectional structural diagram of the separation hook installation and cooperation in Embodiment 1 of the present application;

FIG6 is a schematic diagram of a partial cross-sectional structure of the arc-shaped conductive block and the positioning rod installed in Embodiment 2 of the present application.

In the figure, 1, melting tube; 11, fuse; 111, narrow neck; 12, push rod; 13, reset member; 131, reset spring; 132, arc-shaped conductive block; 133, positioning rod; 1331, retaining ring; 134, compression spring; 2, insulating porcelain bottle; 21, upper bracket; 22, lower bracket; 221, placement gap; 23, static contact piece; 231, reinforcing convex strip; 232, protruding part; 2321, limiting groove; 24, extrusion spring; 3, upper conductive sleeve; 31, positioning through hole; 32, positioning sink groove; 4, lower conductive sleeve; 41, locking through hole; 42, connecting protrusion; 43, elastic conductive sheet; 5, connecting frame; 51, fixed shaft; 52, conductive protrusion; 6, locking member; 61, separation hook; 611, abutment plate; 612, rotating shaft; 62, torsion spring.

DETAILED DESCRIPTION

The present application is further described in detail below in conjunction with all the accompanying drawings.

Embodiment 1:

1 and 2, a drop-out current-limiting fuse includes a melting tube 1 and an insulating porcelain bottle 2, wherein an upper conductive sleeve 3 and a lower conductive sleeve 4 are fixedly provided at both ends of the melting tube 1, a connecting frame 5 is hinged on the outer periphery of the lower conductive sleeve 4, a fixed shaft 51 is fixedly provided on the connecting frame 5, an upper bracket 21 and a lower bracket 22 are fixedly provided at both ends of the insulating porcelain bottle 2, a static contact piece 23 abutting against the upper conductive sleeve 3 is fixedly provided on the upper bracket 21, and a placement notch 221 for inserting the fixed shaft 51 is opened on the lower bracket 22;

An insulating push rod 12 and a fuse 11 wound on the insulating push rod 12 are arranged inside the fusion tube 1. The two ends of the fuse 11 are respectively in contact with the upper conductive sleeve 3 and the lower conductive sleeve 4. A reset member 13 in a compressed state is arranged between the insulating push rod 12 and the upper conductive sleeve 3. A locking member 6 for locking the fixed shaft 51 is hinged on the outer periphery of the lower conductive sleeve 4. A locking through hole 41 for the insulating push rod 12 to pass through is opened on the lower conductive sleeve 4.

When in use, the fuse is placed at an angle. When the fuse 11 breaks, the circuit connected to the fuse is disconnected, and the reset member 13 in the compressed state is reset, thereby squeezing the insulating push rod 12, so that the lower end of the insulating push rod 12 passes through the locking through hole 41 and can release the lock of the locking member 6 on the fixed shaft 51. At this time, the fuse tube 1 falls rapidly because the locking member 6 unlocks the fixed shaft 51, forming an obvious disconnection position.

3 , a plurality of narrow necks 111 are provided on the fuse 11. When the current connected to the fuse is too large, the fuse 11 with multiple narrow necks 111 uses the excessive current to pass through the multiple narrow necks 111, thereby melting the fuses 11 at the same time, and its current limiting action is obviously much faster than that of the traditional fuse 11, thereby improving the performance of the fuse.

2 and 4, the upper conductive sleeve 3 and the lower conductive sleeve 4 are fixedly sleeved on the upper end and the lower end of the melting tube 1, respectively, and the connecting frame 5, the fixed shaft 51, the upper bracket 21 and the lower bracket 22 are all made of conductive metal. A plurality of reinforcing ridges 231 are provided on the side of the static contact piece 23 facing the upper conductive sleeve 3, and the reinforcing ridges 231 are stamped and formed by a stamping device to enhance the structural strength of the static contact piece 23.

Referring to Figure 4, a compression spring 24 in a compressed state is fixedly provided on the side of the upper bracket 21, and the other end of the compression spring 24 is pressed against the side of the static contact piece 23 away from the upper conductive sleeve 3; a protrusion 232 is provided on the side of the static contact piece 23 away from the upper conductive sleeve 3, wherein a limiting groove 2321 is provided on the side of the protrusion 232 facing the upper conductive sleeve 3 for the end of the upper conductive sleeve 3 away from the melting tube 1 to be clamped, and the end of the compression spring 24 away from the upper bracket 21 is sleeved on the outside of the protrusion 232.

2 and 4, the reset member 13 includes a reset spring 131 between the upper conductive sleeve 3 and the insulating push rod 12, wherein one end of the reset spring 131 is fixedly mounted on the inner wall of the upper conductive sleeve 3. When the circuit connected to the fuse operates normally, the reset spring 131 is in a compressed state; after the fuse 11 is broken, the compression of the reset spring 131 is released, and the reset spring 131 is reset, thereby compressing the insulating push rod 12, so that the lower end of the insulating push rod 12 passes through the locking through hole 41 and releases the locking member 6 from locking the fixed shaft 51.

5 , the locking member 6 is a separation hook 61 hinged on the outer periphery of the lower conductive sleeve 4 through a rotating shaft 612, and an abutment plate 611 located below the locking through hole 41 is integrally formed on the end of the separation hook 61 facing the melting tube 1, and a torsion spring 62 for making the separation hook 61 buckle on the outer periphery of the fixed shaft 51 is sleeved on the rotating shaft 612;

When the line to which the fuse is connected is operating normally, the release hook 61 is tightly fastened to the outer periphery of the fixed shaft 51 under the torsion force of the torsion spring 62; when a line fault occurs, the fuse 11 breaks, and the reset member 13 in the compressed state resets and squeezes the insulating push rod 12, so that the lower end of the insulating push rod 12 passes through the locking through hole 41 and squeezes the abutment plate 611, thereby releasing the lock of the release hook 61 on the fixed shaft 51.

5 , a connection protrusion 42 is fixed on the outer periphery of the lower conductive sleeve 4 , an elastic conductive sheet 43 is fixed on the connection protrusion 42 , and a conductive protrusion 52 that can be tightly pressed against the elastic conductive sheet 43 is fixed on the connecting frame 5 , thereby improving the stability of current transmission.

The implementation principle of the embodiment of the present application is:

When in use, the fuse is placed at an angle; when the circuit to which the fuse is connected operates normally, the reset spring 131 is in a compressed state, and the separation hook 61 is tightly fastened to the outer periphery of the fixed shaft 51 under the torsion force of the torsion spring 62. At the same time, the elastic conductive sheet 43 on the lower conductive sleeve 4 abuts against the conductive protrusion 52 on the connecting frame 5 and can provide current transmission, thereby improving the stability during current transmission.

When the fuse 11 breaks, the circuit connected to the fuse is disconnected, and the reset spring 131 in the compressed state is reset, and then the insulating push rod 12 is squeezed through the retaining ring 1331, so that the lower end of the insulating push rod 12 passes through the locking through hole 41 and squeezes the abutment plate 611, thereby releasing the lock of the separation hook 61 on the fixed shaft 51.

Embodiment 2:

6 , the difference between the embodiment of the present application and embodiment 1 is that the reset member 13 also includes an arc-shaped conductive block 132 located outside the upper conductive sleeve 3 and a positioning rod 133 fixed on the arc-shaped conductive block 132, wherein the arc-shaped conductive block 132 and the positioning rod 133 are both made of conductive metal, and a positioning through hole 31 for the positioning rod 133 to pass through is provided on the upper conductive sleeve 3, and the outer periphery of the positioning rod 133 abuts against the inner wall of the positioning through hole 31; a retaining ring 1331 is fixed on the outer periphery of the end of the positioning rod 133 inserted into the upper conductive sleeve 3, and the reset spring 131 is sleeved on the outer periphery of the telescopic rod, and the lower end of the reset spring 131 abuts against one side of the retaining ring 1331.

6 , a compression spring 134 is sleeved on the outer periphery of the positioning rod 133, and a positioning groove 32 is provided on the outer opening edge of the positioning through hole 31 for the lower end of the compression spring 134 to be placed, wherein the elastic force of the compression spring 134 is less than the elastic force of the reset spring 131; when the fuse 11 is broken, the reset spring 131 is reset, and then the arc-shaped conductive block 132 is pulled away from the static contact piece 23 through the positioning rod 133, so that the compression spring 134 is completely compressed into the positioning groove 32, and then the arc-shaped conductive block 132 and the static contact piece 23 are separated, so that the fuse tube 1 is subsequently flipped downward, thereby improving the performance of the fuse when it is used.

Unless otherwise defined, the terms or scientific terms used in this application should be understood by people with ordinary skills in the field to which this application belongs. The "first", "second", "third" and similar words used in this application do not indicate any order, quantity or importance, but are only used to distinguish different components. "One" or "one" and other similar words do not indicate a quantitative limit, but indicate that there is at least one. "Including" or "comprising" and other similar words mean that the elements or objects appearing in front of "including" or "comprising" cover the elements or objects listed after "including" or "comprising" and their equivalents, and do not exclude other elements or objects. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

The embodiments of this specific implementation are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. The same components are represented by the same figure marks. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims (10)

1. The drop-out current limiting fuse comprises a fusion tube (1) and an insulating porcelain bottle (2), wherein an upper conductive sleeve (3) and a lower conductive sleeve (4) are respectively and fixedly arranged at two ends of the fusion tube (1), a connecting frame (5) is hinged to the periphery of the lower conductive sleeve (4), and a fixing shaft (51) is fixedly arranged on the connecting frame (5); an upper bracket (21) and a lower bracket (22) are respectively and fixedly arranged at two ends of the insulating porcelain bottle (2), a static contact piece (23) which is abutted to the upper conductive sleeve (3) is fixedly arranged on the upper bracket (21), and a placement notch (221) for placing the fixed shaft (51) is formed in the lower bracket (22);

The fuse tube is characterized in that a locking piece (6) for locking a fixed shaft (51) is hinged to the periphery of the lower conductive sleeve (4), an insulating push rod (12) and a fuse wire (11) wound on the insulating push rod (12) are arranged in the fuse tube (1), two ends of the fuse wire (11) are respectively connected with the upper conductive sleeve (3) and the lower conductive sleeve (4), a resetting piece (13) in a compressed state is arranged between the insulating push rod (12) and the upper conductive sleeve (3), and a locking through hole (41) is formed in the lower conductive sleeve (4); after the fuse wire (11) is broken, under the action of the reset piece (13), the lower end part of the insulating push rod (12) can penetrate through the locking through hole (41) and unlock the fixed shaft (51) by the locking piece (6).

2. The drop-out current limiting fuse according to claim 1, wherein the locking member (6) is a separating hook (61) hinged on the periphery of the lower conductive sleeve (4) through a rotating shaft (612), one end of the separating hook (61) is fixedly provided with an abutting plate (611) located below the locking through hole (41), and the rotating shaft (612) is sleeved with a torsion spring (62) for enabling the separating hook (61) to be buckled on the periphery of the fixed shaft (51).

3. A drop-out current limiting fuse as claimed in claim 1, wherein the reset member (13) comprises a reset spring (131) between the upper conductive sleeve (3) and the insulating push rod (12), and one end of the reset spring (131) is fixedly arranged on the inner wall of the upper conductive sleeve (3).

4. A drop-out current limiting fuse according to claim 3, wherein the reset member (13) further comprises an arc-shaped conductive block (132) located outside the upper conductive sleeve (3) and a positioning rod (133) fixedly arranged on the arc-shaped conductive block (132), the upper conductive sleeve (3) is provided with a positioning through hole (31) for the positioning rod (133) to penetrate through, the positioning rod (133) is inserted into the outer periphery of the end part of the upper conductive sleeve (3) and fixedly provided with a retaining ring (1331), and the reset spring (131) is sleeved on the outer periphery of the telescopic rod and is in butt joint with one side of the retaining ring (1331).

5. The drop-out current limiting fuse of claim 4, wherein the positioning rod (133) is provided with a compression spring (134) on the outer periphery thereof, and a positioning sink (32) for placing the end of the compression spring (134) is provided at the edge of the outer opening of the positioning through hole (31).

6. A drop-out current limiting fuse as claimed in claim 1, wherein the fuse wire (11) is provided with a plurality of necks (111).

7. The drop-out current limiting fuse of claim 1, wherein a connection lug (42) is fixedly arranged on the periphery of the lower conductive sleeve (4), an elastic conductive sheet (43) is fixedly arranged on the connection lug (42), and a conductive lug (52) capable of being abutted against the elastic conductive sheet (43) is fixedly arranged on the connecting frame (5).

8. The drop-out current limiting fuse of claim 1, wherein a compression spring (24) in a compressed state is fixedly arranged on the side surface of the upper bracket (21), and the other end of the compression spring (24) is abutted against the side surface of the static contact piece (23) far away from the upper conductive sleeve (3).

9. The drop-out current limiting fuse of claim 8, wherein a protruding portion (232) is disposed on a side surface of the static contact piece (23) away from the upper conductive sleeve (3), a limit groove (2321) in which an end portion of the upper conductive sleeve (3) away from the fusion tube (1) is clamped is formed in a side surface of the protruding portion (232) facing the upper conductive sleeve (3), and an end portion of the extrusion spring (24) away from the upper bracket (21) is sleeved outside the protruding portion (232).

10. A drop-out current limiting fuse according to claim 1, wherein the side of the stationary contact (23) facing the upper conductive sleeve (3) is provided with reinforcing ribs (231).