Connection structure of spiral fuse base and fuse link

Abstract

The new spiral fuse base and fuse link have a new structure. The fuse base shell is changed from porcelain to metal, and a layer of engineering plastic with good insulation performance is added inside the shell. The anti-loosening module is changed to a spring type, which enhances the strength of the base, increases the creepage distance, and reduces the friction of the anti-loosening module on the fuse contact, which may cause damage to the electroplating layer. The fuse tube of the fuse link is also made of plastic. The fuse is set to a variable cross-section and has a certain angle bend along the length to stagger the arcing angle. The forming parts at both ends are changed to a retractable L-shape, which improves the vibration and impact resistance, makes the structure more stable, prolongs the service life, and improves the breaking capacity. It can be used to protect electrical equipment in non-stationary states such as road vehicles, civilian ships and military ships, machine tools / lathes, rail transportation, aviation / space launch devices and other fields.

Description

Technical Field

[0001] The present invention relates to the field of protection of power transmission lines and electrical equipment, and in particular to a spiral fuse base and a fuse element for protecting power transmission lines and electrical equipment. Background Art

[0002] A fuse is an electrical device that generates heat to melt its fuse element, disconnecting the circuit when the current exceeds a specified value. When used, the fuse is connected in series with the circuit being protected. When an overload or short-circuit current flows through the fuse element, it heats up and melts, thus protecting the power system, electrical equipment, and various electrical devices. It has an inverse time-delay characteristic: when the overload current is low, the fuse takes a long time to open; when the overload current is high, the fuse takes a short time to open. Therefore, within a certain overload current range, the fuse will not open until the current returns to normal, allowing continued use.

[0003] The spiral fuse is generally composed of a porcelain cap, a fuse tube, a porcelain sleeve, an upper terminal block, a lower terminal block and a porcelain base. It refers to a fuse with a fuse-carrying element that is fixed to the base by screwing it into the base. It has the characteristics of large breaking capacity, small size, display after the fuse is melted, easy replacement of the fuse, safety and reliability. It is widely used in distribution boxes, control boxes and occasions with large vibration in the electrical control systems of low-voltage power distribution equipment, ships, machine tools and other equipment as overload and short-circuit protection components.

[0004] The threads (threaded tubes) installed in the upper cap (upper end) and lower base (lower end) of the common spiral fuse base are used to fix the fuse link, allowing the installed fuse link to be tightly and reliably connected to the upper and lower terminals (load ends). The threaded tubes are made of pure metal (mostly copper and steel), so that they can communicate with the load end of the circuit, so that the circuit can be reliably and stably connected to the fuse link. In order to ensure that the conductive cloth (contact) of the fuse link installed in the base can better connect with the conductive terminal set on the base and reduce contact resistance, a certain elastic anti-loosening module is installed at the bottom of the base cap. The currently commonly used anti-loosening module is a one-piece V-shaped card. When the fuse link is pressed down, the V-shaped opening narrows, and when there is no fuse link pressed down, the V opening widens. The fuse tube used by the fuse link is the same as the exterior of the base, both are made of porcelain. After being used in many occasions, the disadvantages of spiral fuses with this material and structure have been found to be:

[0005] 1. The threaded connection between the upper cap and the lower base is made of pure metal and is in direct contact with the fuse tube of the fuse-link housed in the porcelain sleeve, affecting electrical specifications such as insulation resistance, electrical intermittent, and creepage distance. While this may be acceptable in environments with low voltage, low current, low interruption, and short-time withstand current requirements, it is not suitable for environments with high demands on these specifications. Simply increasing the current density flowing through the fuse element to improve the breaking capacity of the fuse-link cannot be relied upon without increasing the overall dimensions of the tube body and the size or number of the fuse elements within the fuse link. This will result in a series of defects such as difficulty in heat dissipation, temperature rise, and high power consumption, necessitating the use of alternative products or an increase in size.

[0006] 2. The outer materials of the fuse tube, upper cap and lower seat of the fuse link are all made of porcelain. Due to the inherent characteristics of this material, when used in occasions / environments with tilt, swing, bump, impact and vibration, the stability and reliability will be greatly reduced.

[0007] 3. The anti-loosening module adopts a card type. When installing the fuse link and entering the operation process, this type of module can easily damage the electroplating layer of the fuse contact (outer cover) because the protected system (equipment) is not in a static state, which will reduce the quality indicators such as temperature rise and current carrying capacity. Summary of the Invention

[0008] To address the above shortcomings, the present invention aims to provide a novel spiral fuse base and fuse link. In this structure, the fuse base housing is made of metal instead of porcelain, and a layer of engineering plastic with good insulating properties is added inside the housing. The anti-loosening module is spring-type, which enhances the strength of the base, increases the creepage distance, and reduces the friction of the anti-loosening module on the fuse contacts, which may damage the electroplating layer. The fuse tube of the fuse link is also made of plastic. The fuse element is configured with a variable cross-section and is bent at a certain angle along its length to stagger the arcing angle. The molded portions at both ends are retractable L-shaped, which improves vibration and impact resistance, makes the structure more stable, prolongs the service life, and improves the breaking capacity. The present invention can be applied to protecting electrical equipment in non-stationary states, such as road vehicles, civilian ships and military vessels, machine tools / lathes, rail transportation, and aviation / space launch vehicles.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] 1. The connection structure of the spiral fuse base and the fuse link, including a base ring, a base inner ring, an outer cap, an inner cap, a fuse link, an anti-loosening module, an anti-loosening module seat, a contact rod, a screw, a fixing plate, an upper cover and an O-ring. The base inner ring is inserted into the base ring, and the contact rod is installed in the anti-loosening block seat in a knob manner. The anti-loosening module is provided on the upper part of the anti-loosening block seat. The screw passes through the anti-loosening module and is installed in the anti-loosening block seat in a knob manner. After installation, the anti-loosening module is sunk to the bottom of the base inner ring through the contact rod passing through the through-hole provided on the base inner ring. The end of the contact rod passing through the base inner ring serves as one of the load ends for connection with the electrical equipment, and an O-ring made of elastic plastic is provided at the bottom of the contact rod passing through the outside of the base ring to facilitate the connection and compression fixation of the contact rod with the electrical equipment and increase the creepage distance between the fuse link and the wire line;

[0011] The fuse is installed in the inner ring of the base. A fixing plate is provided in the inner ring. The fixing plate is made of pure copper so that the fuse contact is in full contact with the conductive circuit and prevents the fuse from shaking due to excess space in the inner ring of the base. An upper cover is provided on the top of the outer cap of the fuse. The inner cap is inserted into the outer cap and is installed on the base ring in a knob manner through a threaded ring provided in the inner cap, thereby pressing and fixing the installed fuse inside.

[0012] The characteristic is that in order to increase the creepage distance between the fuse base and the fuse element, the base inner ring and inner cap in contact with the fuse tube of the fuse element are newly added and are made of plastic material with good insulation and high voltage resistance.

[0013] 2. The outer layer of the base ring is provided with a load terminal connected to the circuit.

[0014] 3. An observation window is provided on the upper cover portion of the outer cap.

[0015] 4. A concave ring is provided on the upper part of the anti-loosening module seat for installing the anti-loosening module, and an energy storage spring is provided between the anti-loosening module and the anti-loosening module seat.

[0016] 5. An auxiliary fuse is provided inside the fuse, and a fuse indicator is provided on the top of one end to display and observe the working status of the fuse.

[0017] 6. The fuse tube of the fuse link contains plastic or resin materials to improve the ability to resist impact, vibration and bumps.

[0018] 7. The inner cavity of the fuse is filled with arc extinguishing medium.

[0019] 8. The fuse element is designed with a variable cross-section and is bent at a certain angle along the length direction to stagger the arcing angles. The forming parts at both ends are retractable L-shaped to improve vibration and impact resistance.

[0020] 9. The gaps between the fuse tube and the interface contacts and the blown fuse indicator are filled with silica gel to prevent sand leakage and arc ejection during breaking, and to prevent moist air from entering the tube, causing melt oxidation and copper / silver ion migration.

[0021] 10. The base and circuit load connection materials as well as the inner and outer covers of the fuse body used for conductivity are all made of copper with silver plating to reduce temperature rise and improve current carrying capacity.

[0022] Compared with common fuses currently on the market, the most notable feature of the spiral fuse base and fuse-link connection structure of the present invention is the addition of a plastic inner ring at the contact point between the base and the fuse tube. Furthermore, the base housing in conventional solutions is changed from porcelain to metal or plastic, and the fuse tube is made of porcelain instead of plastic or resin. This not only increases the creepage distance between the base and the fuse, but also overcomes the inherent limitations of porcelain in terms of resistance to moisture, heat, vibration, and impact. As a result, spiral fuse bases and fuse links of the same dimensions and in the same environment can achieve improved breaking capacity and current carrying capacity while also improving stability, durability, reliability, and service life.

[0023] The fuse element installed in the fuse link is set to a variable cross-section and is bent at a certain angle along the length direction to stagger the arcing angles. The forming parts at both ends are retractable L-shaped, which not only shortens the arcing time but also improves the vibration and impact resistance.

[0024] The anti-loosening module is changed from a card type to a telescopic spring type. Although the manufacturing process and procedures are increased, it can not only reduce or lower the wear of the contact block on the fuse contact (outer cover) and protect the electroplating layer from being damaged, but also because this design uses a spring, the contact between the anti-loosening module and the fuse contact (outer cover) is closer, and the contact resistance is correspondingly reduced, which is conducive to reducing the temperature rise during operation.

[0025] Using silicone as the filler for the gaps between the fuse tube and the interface contacts and fuse indicator can effectively prevent sand leakage and arc ejection during disconnection, while preventing moist air from entering the tube, causing melt oxidation and copper / silver ion migration. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0027] Figure 2 Schematic diagram of the exploded structure of the finished product of an embodiment of the present invention.

[0028] Figure 3 It is a schematic diagram of the explosion of the finished product structure of the fuse link according to the embodiment of the present invention.

[0029] Figure 4 It is a schematic diagram of the three-dimensional structure of the anti-loosening module according to an embodiment of the present invention.

[0030] Figure 5 This is a schematic diagram of the overall structure of the lower end of the base according to an embodiment of the present invention.

[0031] Explanation of the accompanying reference numerals: 1. Base ring; 2. Outer cap; 3. Inner cap; 4. Inner ring of base; 5. Fuse link; 6. Anti-loosening module seat; 7. Screw; 8. Anti-loosening module; 9. Energy storage spring; 10. Contact rod; 11. Fixing plate; 12. Upper cover; 13. O-ring; 101. Threaded ring; 102. Load end connecting block; 501. Melting tube; 502. Melt; 503. Inner cover; 504. Contact; 505. Auxiliary melt; 506. Fuse indicator. DETAILED DESCRIPTION

[0032] The present invention will be further described below with reference to the accompanying drawings.

[0033] Examples, such as the attached Figure 1 、 2 As shown in the figure, the connection structure of the spiral fuse base and fuse link includes a base ring 1, an outer cap 2, an inner cap 3, a base inner ring 4, a fuse link 5, an anti-loosening module seat 6, a screw 7, an anti-loosening module 8, an energy storage spring 9, a contact rod 10, a fixing plate 11, an upper cover 12, and an O-ring 13. When the base is produced and installed, it can be divided into three modules and then assembled after they are manufactured separately:

[0034] The first module: the lower part of the base (the lower end of the base), there are 3 spare parts, the base ring 1 is made of metal, the base inner ring 2 is made of plastic, and the O-ring 13 is made of elastic plastic. The base inner ring 2 is physically pressed by special equipment and inserted into the inside of the base ring 1. Then, the O-ring 13 is placed on the concave part of the base inner ring 2 exposed outside the base ring 1. The production of the lower part of the base is basically completed. As shown in the attached figure Figure 5 As shown, an external thread ring 101 is provided on the base ring 1 for connecting with the internal thread ring provided in the inner ring 3 on the base cap, and the load end connection block 102 provided on the base ring 1 is used to connect to the other end of the circuit on the one hand, and on the other hand, the base can be connected to the fixed power line or protected equipment through the through-hole provided at this end, and together with the connecting rod 12, it plays the role of stabilizing and fixing the base.

[0035] The second module: the base cap (i.e. the upper part of the base), has 4 spare parts, the outer cap 2 is made of metal, the inner cap 3 is made of plastic, the fixing plate 11 is made of elastic pure copper and is processed into an O-shape with an opening, and the upper cover 12 is made of transparent glass or plastic; the same as the lower part of the base, the inner cap 3 is physically pressurized by special equipment to make it fit into the inner circle of the outer cap 2, and then the upper cover 12 is installed on the top of the outer cap 2, and then the fixing plate 11 is arranged in the inner cavity of the inner cap 3.

[0036] The third module: anti-loosening block, as attached Figure 4 As shown, there are 4 accessories, all of which are made of metal, namely, the contact rod 12, the energy storage spring 9, the anti-loosening module 8, the anti-loosening module seat 6 and the screw 7; first, place the energy storage spring 9 into the energy storage spring mounting hole set in the concave ring on the upper part of the anti-loosening module seat 6, then place the anti-loosening module 8 into the concave ring, and then insert the screw 7 through the screw through-hole set on the anti-loosening module 8, and pass through the energy storage spring 9 to screw into the threaded hole at the bottom of the concave ring on the upper part of the anti-loosening module seat 6, and finally install the contact rod 12 to the lower part of the anti-loosening module seat 6.

[0037] During installation and assembly, first pass the contact rod 12 of the anti-loosening block through the through-hole provided on the base inner ring 2 at the lower part of the base, so that the installed anti-loosening module 8 is sunk to the bottom of the base inner ring 2 through the contact rod 12, and the contact rod 12 passes through the base inner ring 2 as one end of the load end for connection with the electrical equipment;

[0038] Next, the fuse 5 is first inserted into the second module, that is, the inner cavity of the inner cap 3, with the conductive contact portion inserted into the fixing plate 11 and fully contacting the fixing plate. Then, the base cap portion is docked with the lower part of the base. The external thread ring 101 provided on the outside of the base ring 1 and the internal thread ring provided on the inside of the inner cap 3 (not shown in the figure) are rotated together to tighten the fuse 5 installed inside, press the anti-loosening module 8 and retract the energy storage spring 9, so that the contact portions at both ends are fully in contact with the copper conductive portions on the base inner ring 2 and the inner cap 3.

[0039] Regarding the manufacture and installation of fuse links, see the attached Figure 3As shown, the main components include: a fuse tube 501, a fuse element 502, an inner cover 503, a contact 504, an auxiliary fuse element 505, a fuse indicator 506, and an arc-quenching filler (not shown). First, the inner covers 503 are installed at both ends of the fuse tube 501. The fuse element 502 is then passed through the fuse tube 501 and its ends are welded to the inner covers 503 at both ends of the fuse tube 501. A fuse indicator 506 is then welded to one end of the auxiliary fuse element. The end without the fuse indicator 506 is passed through the contact 504 with a perforation at one end and then passed through the fuse tube 501. The contact with the fuse indicator 506 inserted is interference-fitted to the fuse tube 501 by press-riveting. The other end is welded to the inner cover 503. Arc-quenching filler is then filled into the inner cavity of the fuse tube 501 at this end. Finally, a contact is installed at this end, completing the installation of the fuse element.

[0040] In order to effectively prevent sand leakage and arc emission during disconnection, and to prevent moist air from entering the tube body, causing melt oxidation and copper / silver ion migration, the gaps between the fuse tube, the interface contact, and the fuse indicator are filled with silicone in the embodiment to improve the sealing performance.

Claims

1. The connection structure of the spiral fuse base and the fuse body includes a base ring, a base inner ring, an outer cap, an inner cap, a fuse body, an anti-loosening module, an anti-loosening module seat, a contact rod, a screw, a fixing plate, an upper cover and an O-ring. The base inner ring is inserted into the base ring, and the contact rod is installed in the anti-loosening block seat in a knob manner. The anti-loosening module is provided on the upper part of the anti-loosening block seat. The screw passes through the anti-loosening module and is installed in the anti-loosening block seat in a knob manner. After installation, the anti-loosening module is sunk to the bottom of the base inner ring through the contact rod passing through the through hole provided on the base inner ring. The contact rod passes through the base inner ring part as one end of the load end for connection with the electrical equipment, and An O-ring made of elastic plastic is provided at the bottom of the contact rod extending beyond the base ferrule to facilitate connection, compression, and fixation of the contact rod to the electrical equipment and increase the creepage distance between the fuse link and the conductor line. The fuse link is mounted within the inner ring of the base, within which a fixing plate made of pure copper is provided to ensure full contact between the fuse link contacts and the conductive line and prevent the fuse link from shaking due to excess space within the inner ring of the base. An upper cover is provided on the top of the outer cap of the fuse link, which is inserted into the inner cap and is mounted to the base ferrule in a knob-like manner via a threaded ring provided in the inner cap, thereby pressing and fixing the installed fuse link. The invention is characterized in that: In order to increase the creepage distance between the fuse base and the fuse link, the base inner ring and inner cap in contact with the fuse tube are newly added. They are made of plastic materials with good insulation and high voltage resistance. The fuse element is designed with a variable cross-section and a certain angle of bend along the length direction to stagger the arcing angle. The forming parts at both ends are retractable L-shaped to improve the vibration and impact resistance. The gaps between the fuse tube, the interface contact and the fuse indicator are filled with silica gel to prevent sand leakage and arc emission during disconnection, and to prevent moist air from entering the tube, causing melt oxidation and copper / silver ion migration.

2. The connection structure of the spiral fuse base and fuse link according to claim 1, characterized in that: The outer layer of the base ring is provided with a load end connected to the circuit.

3. The connection structure of the spiral fuse base and fuse link according to claim 1, characterized in that: An observation window is provided on the upper cover portion of the outer cap.

4. The connection structure of the spiral fuse base and fuse link according to claim 1, characterized in that: A concave ring is provided on the upper portion of the anti-loosening module seat for installing the anti-loosening module, and an energy storage spring is provided between the anti-loosening module and the anti-loosening module seat.

5. The connection structure of the spiral fuse base and fuse link according to claim 1, characterized in that: An auxiliary fuse is provided inside the fuse, and a fuse indicator is provided on the top of one end thereof so as to display and observe the working state of the fuse.

6. The connection structure of the spiral fuse base and fuse link according to claim 1, characterized in that The fuse tube of the fuse link contains plastic or resin materials to improve its resistance to impact, vibration and bumps.

7. The connection structure of the spiral fuse base and fuse link according to claim 1, characterized in that: The inner cavity of the fuse is filled with arc extinguishing medium.

8. The connection structure of the spiral fuse base and fuse link according to claim 1, characterized in that: The base and the circuit load connection material as well as the inner cover and outer cover of the fuse body used for conducting electricity are all made of copper plated with silver to reduce temperature rise and improve current carrying capacity.

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