JP3682707B2 - High current packaging fuse with cable - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a large current packaging fuse with a low voltage cable mainly used for automobiles.
[0002]
[Prior art]
In order to protect electrical / electronic equipment and wiring and power supply from excessive fault current, and to prevent smoke, fire and fire, large-current fuses have been used mainly in passenger cars since the late 1975s. A large current fuse of 60 A or more is widely used in automobile main circuits. Up to now, for example, a cartridge type large current fuse (hereinafter referred to as a cartridge type large current fuse) having a screw terminal portion as shown in FIG. 6 has been widely used in domestic cars. That is, the structure includes a housing 10 formed of an insulator, a fuse element 6 having a screw terminal 9 and a cover 8, and the screw terminal 9 protrudes from the housing 10 when the fuse element 6 is incorporated in the housing 10. A large current fuse (see Japanese Patent Application Laid-Open Nos. 5-274959, 6-290699 and 59-41563). As shown in FIG. 7, a fuse having a structure in which a fuse element 6 having conical terminals 12 at both ends is wound around the surface of an insulator 13 (hereinafter referred to as an insulator-type high-current fuse) is also mainly used in German cars. Have been used (see DIN 72581). The cartridge type large current fuse and the insulator type large current fuse (hereinafter referred to as a conventional large current fuse) are housed and wired together with other fuses in a specially provided fuse box.
The fuse is required to have a time lag characteristic. In other words, when a failure occurs, it operates instantaneously to protect the circuit, while it does not operate as much as possible to a non-failure current flowing in a device having a large starting load such as a motor. In a conventional high current fuse, in order to provide a time lag characteristic, a low melting point metal chip is held on the fuse element, a part of the fuse element is brought into contact with an insulator such as ceramic, or a part of the fuse element is attached. A method such as embedding in an endothermic body made of an insulator is employed.
[0003]
[Problems to be solved by the invention]
More and more electric / electronic devices are installed in automobiles, increasing power consumption and reducing the weight of the car despite the increased cross-sectional area and length of the wires used for wiring There is a demand for minimizing the weight of electric wires used for wiring as the demand for vehicle performance has been increasing. For this reason, the conventional high-current fuse is taken out from the fuse box, the size of the fuse box is reduced as much as possible to reduce the weight, or the high-current fuse is directly or close to a specific part (for example, a cell motor) in the engine room. Therefore, it has become necessary to simplify the wiring of the main circuit to reduce the weight and to effectively use the volume of the engine room.
Installation of the conventional high-current fuse requires a fuse box, and it is structurally difficult to install directly or in close proximity to a specific part in the engine room, and a dedicated fuse box is provided to simplify the main circuit. Even so, the amount of Joule heat generated by the energizing current is large, and inconveniences such as deformation of the fuse hook due to temperature rise occur, so there is a limit to downsizing the fuse box, and it is not possible to install the fuse box in a narrow space That is, there is a problem that the light weight target cannot be achieved and the arrangement density cannot be increased by downsizing the fuse hook. In particular, the insulator-type high-current fuse has a structure in which a fusible element is exposed and a conical terminal is inserted into the holder, and since the contact resistance of the terminal part is large, the amount of heat generation is large and the size cannot be reduced. It is. In order to simplify the main circuit of an automobile, a large current fuse with a small time lag characteristic and a low calorific value is required. However, in the conventional large current fuse, the fuse element is usually plate-shaped and copper is used as the material. ing. For this reason, a metal or alloy having a low melting point necessary for making a fuse having a strong time lag characteristic and a small calorific value cannot be used as a fuse element, and the shape of the fuse element is limited to a plate shape. As described above, in the conventional high-current fuse, in order to have a time lag characteristic, a low melting point metal chip is held in the fuse element, a part of the fuse element is brought into contact with an insulator such as ceramic, or the fuse element A method such as embedding a part of this in an endothermic body made of an insulating material is employed. As a result, part of the Joule heat due to the energizing current moves to the low melting point metal or insulator that is in contact with the fuse element, and the amount of heat necessary for the fuse element to melt increases, resulting in a time lag characteristic. However, since the amount of heat transferred varies depending on the contact area and contact state between the fuse element and the low melting point metal or insulator, there is a large variation in fusing time between products, and overcurrent that exceeds the rated current There is a problem in that the fusing time changes when the gas flows for a long time. In particular, in a cartridge type high current fuse in which a low melting point metal chip is held in a fuse element, an alloy is formed by melting the low melting point metal due to overcurrent and diffusing into the fuse element, and the composition of the fuse element changes, Since the resistivity increases and the melting point decreases, the current carrying capacity decreases, and the reliability for long-term use is lacking.
The problem to be solved by the present invention is an in-line that can be mounted directly or close to a specific device or part in a narrow engine room of an automobile, and that reduces the amount of heat generated to simplify the main circuit of the automobile. It is an object of the present invention to provide a high-current fuse that can be used reliably for a long period of time with little change in the fuse element over time even under harsh atmosphere and vibration conditions.
[0004]
[Means for Solving the Problems]
The fuse according to the present invention solves the above-described problems and is as follows. First, the fuse according to the present invention is a packaging fuse. That is, the fuse element that melts when an overcurrent flows is confined in a sealed space formed by the insulating cylinder and the cap. In this specification, the “cap” is a cap-shaped metal that is integrated with a crimping portion or a screw terminal portion of a cable attached to both ends of an insulating cylinder, and forms a part of the fuse body together with the insulating cylinder. . Further, in this specification, “automobile main circuit” is a circuit connecting a battery, an alternator (alternator) and a starter. In the fuse according to the present invention, two types of caps are used. That is, a cable crimp terminal integrated cap in which the crimp terminal portion for connecting the cable is integrated and a screw clamp terminal cap in which the screw terminal portion for fastening the bolt / nut is integrated. There are two types. The cable crimp terminal integrated cap has a flat metal plate part between the cap and the cable crimp terminal part, and the metal plate of the flat metal plate part between the cap and the cable crimp terminal part has a side surface of the cap. The cable crimp terminal portion is provided integrally with the cap so that the cable and the side surface of the cap are perpendicular to each other when the cable is perpendicular and one end of the cable is fixed to the cable crimp terminal portion. When one end of the cable is fixed to the cable crimping terminal, the side of the cable crimping terminal and the cap are in the vertical direction. This means that the extended surfaces of the crossing at almost right angles. The screw terminal integrated cap has a cap on the metal plate at one end of the metal plate so that the side of the cap is perpendicular to the metal plate, and a through hole is provided on the other end of the metal plate as a screw terminal portion. In addition, the screw terminal portion is integrated with the cap. Two types of fuses are made depending on the cap used. A cable crimp terminal integrated cap is used at both ends of the fuse, a cable is connected to both ends of the fuse (as described in claim 1), and a cable crimp terminal integrated cap is screwed to the other end of the fuse There are two types, one that uses a cap integrated with a fastening terminal and that has a cable connected to only one end of the fuse (described in claim 2). Spiral grooves (male threads) are provided at both ends of an insulating cylinder made of an insulating material such as ceramic, plastic, glass, and the like, and spiral grooves (female threads) that fit together are provided on the cap. When the cap is attached to the insulating cylinder by this screw mechanism and one end of the cable is fixed to the cable crimping terminal portion, the cable and the axis of the insulating cylinder are in the vertical direction. Further, when a bolt is passed through the through hole of the screw tightening terminal and tightened with a nut, the axis of the bolt and the axis of the insulating cylinder are in parallel. When there are two stranded wires constituting the fuse element, a silver-plated copper wire is stretched in a straight line as a center wire, and a silver / zinc clad wire with silver as the outer sheath material and zinc as the core material around it as the upper wire It may be wound spirally.
[0005]
[Action]
In the fuse according to the present invention, a crimp terminal portion or a screw fastening terminal portion for connecting a cable is integrated with the cap, and the cap and the insulating cylinder are provided with screw mechanisms that fit into each other. Therefore, the connection between the screw terminal portion and the cable crimp terminal portion and the fuse body is extremely strong, and it is possible to insert the fuse into the main circuit of the automobile with a small contact resistance using the terminal integrated with the cap. it can. In addition, when the cap is attached to the insulation cylinder by a screw mechanism and one end of the cable is fixed to the cable crimp terminal, the cable and the axis of the insulation cylinder are perpendicular to each other. When the cable is fixed and pulled, the cap is not pulled in the axial direction of the insulating cylinder, so it is difficult to remove the cap from the insulating cylinder. For this reason, the strength against pulling and pushing in the axial direction of the cable is extremely high. Furthermore, as shown in Comparative Example 1, the mechanical strength against the vibration in the axial direction of the fuse body can be remarkably increased by the screw mechanism provided in the cap and the insulating cylinder. As a result, it is possible to realize a fuse that is very solid in structure and excellent in vibration resistance. Furthermore, the angle between the cable crimp terminal part and screw terminal part shown in FIG. 4 can be arbitrarily set by the way of cutting the groove of the male screw and the female screw, which satisfies the user's requirements such as the mounting location and mounting angle of the fuse. it can. Since the fuse element is soldered to the cap, the shape and material of the fuse element can be freely selected regardless of the material of the cap. By using a metal or alloy with a low melting point as the material of the fuse element, or by using an appropriate fuse element with a different material as a stranded wire, the time lag characteristics are strong, the resistance value is small, that is, the calorific value is small, and the comparison As shown in Example 2, it is known that a fuse with a small fusing time variation and a fusing time that does not change even when a large overcurrent flows for a long time can be realized. However, the fuse element according to the present invention is required for an automobile fuse. The present invention invents a material and structure that can satisfy various conditions (temperature cycle, vibration resistance, large current rating, etc.) and have the least effect of migration of fuse element components due to long-term energization at high temperatures. A silver / zinc clad wire or a silver / zinc clad wire or a silver / zinc clad wire or a silver / zinc alloy wire with a silver-plated copper wire as a center wire, and a silver wire as an outer shell material and a zinc or zinc-silver alloy core material By using the fuse element according to the present invention in which a zinc-silver alloy clad wire is spirally wound, the melting of silver is suppressed by zinc, and the brittle fracture at the crystal grain boundary of zinc is prevented by the diffusion of the silver. In addition, the desired resistance value and melting point can be obtained. Furthermore, since it is a package fuse, the fuse element is confined in a sealed space. The fuse element is not directly exposed to water vapor, dust, etc., and the change of the fuse element with time is small even in a harsh atmosphere, and the arc that occurs when the fuse element blows and fires has an adverse effect on the surroundings such as ignition, ignition, smoke, etc. I don't give it.
[0006]
[Comparative Example 1]
In order to show that the vibration resistance of the fuse body is significantly improved against the axial vibration of the fuse body by providing a screw mechanism on the cap and insulating cylinder, repeated energization tests and vibration durability in an atmosphere of 80 degrees Celsius An aging test combined with the test was conducted to inspect for looseness between the cap and the insulating cylinder, that is, whether there was any looseness in the connection between the cap and the insulating cylinder.
For bonding the screw-clamping terminal integrated cap and the cable crimping terminal integrated cap and the insulating cylinder, maleimide-based heat-resistant resin was used as an adhesive, and after bonding, it was left in a constant temperature bath at 120 degrees Celsius for 1 hour. Samples provided with a screw mechanism were assembled by applying an appropriate amount of adhesive to the spiral groove of the insulating cylinder. After taking out from the thermostat, a fuse element for a rated current of 120 amps is soldered, and a cable having a cross-sectional area of 20 square millimeters and a length of 50 centimeters is connected to the cable crimping terminal portion of the cap, as shown in FIG. The screw terminal portion of the cap was fixed to the vibration test apparatus, and one end of the cable was fixed to be the same height as the cable crimp terminal portion.
The vibration conditions are vibration acceleration of 44.1 meters per square second, vibration frequency of 20 to 200 Hz, sweep time of 3 minutes, that is, until the frequency continuously increases and decreases from 20 Hz to 200 Hz and back to 20 Hz again. Was set to be 3 minutes. The combined aging test was conducted in an atmosphere of 78 to 82 degrees Celsius with 300 cycles of 1 hour current cycle in which 60 amperes were energized for 45 minutes and the energization was stopped for 15 minutes while applying the vibration described above. The looseness between the cap and the insulating cylinder was confirmed.
Tests were performed on 24 samples each having a screw mechanism and not having a screw mechanism. As a result, no looseness occurred in the sample provided with the screw mechanism, but looseness occurred in six samples in the sample not provided with the screw mechanism.
[0007]
[Comparative Example 2]
In order to show that the variation in fusing time can be kept small by using a stranded wire fuse element, and the change in fusing characteristics due to a large overcurrent flow can be kept to a very small level. 1.6 times the rated current (96A) is passed through a fuse with a rated current of 60A and the fusing time is measured. Further, a fuse with a rated current of 60A without current history is 1.1 times the rated current (66A). Immediately after energizing the overcurrent for 4 hours, 1.6 times the rated current was passed and the fusing time was measured.
The samples used were three different types of fuses, a cartridge type high current fuse (sample A) having a structure shown in FIG. 6 in which a low melting point metal is held in the fuse element, and a part of the fuse element is an insulator. A type of cartridge type large current fuse (sample B) manufactured by Company B, which is embedded in an endothermic body made of the above, and a product of the present invention. A silver-plated copper wire is stretched linearly as a center wire and cut around it as an upper wire. High current packaging fuse with cable according to the present invention using a fuse element having a structure in which a silver / zinc silver alloy clad wire with a silver outer sheath and a zinc silver alloy core as a core is wound with an area ratio of 1: 1 (sample C) It is.
A cable having a cross-sectional area of 8 square millimeters and a length of 80 centimeters was used to connect the sample to the constant current power supply device and ammeter, and the cable was fixed with bolts / nuts. A current that is 1.6 times the rated current was passed through 10 samples each having no energization history, and the fusing time was measured. Further, 10 samples each having no energization history were energized with 1.1 times the rated current for 4 hours, and immediately after that, 1.6 times the rated current was passed to measure the fusing time.
Since the average value of the measured fusing time is different for each sample, the variation cannot be simply compared as it is. Accordingly, the ratio of the average fusing time of each sample to 100 seconds is obtained, and the fusing time converted so that the average fusing time of each sample is 100 seconds is obtained by multiplying each measured value by this ratio. The standard deviation of the fusing time (the square root of the difference between the mean value of the fusing time squared and the square value of the average fusing time) was obtained, and the variations were compared.
The variation when a current of 1.6 times the rated current is passed through a sample without current history and the fusing time is measured is 84 seconds for sample A, 32 seconds for sample B, and 21 seconds for sample C. It can be seen that the variation of the product of the present invention (Sample C) is smaller than that of the large current fuse. In addition, the current of 1.1 times the rated current was passed through the sample without energization history for 4 hours after passing the current of 1.6 times the rated current through the sample without current history for 4 hours. The ratios to the fusing time measured by passing 1.6 times the current were 0.77 for sample A, 0.76 for sample B, and 0.97 for sample C. In any sample, the fusing time is shortened by energizing the overcurrent for 4 hours, or in the case of the cartridge type high current fuse, the fusing time is reduced by 23% to 24% on average. In sample C), the average fusing time reduction is only 3%.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
[Example 1]
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view showing the first embodiment, and FIG. 2 is an exploded perspective view of a main portion of the high-current fuse with cable shown in FIG. 2 is a screw terminal integrated cap, 3 is an insulating cylinder, and 4 is a cable. Reference numeral 5 denotes a cable crimping terminal integrated cap, and 6 denotes a fuse element. The screw tightening terminal integrated cap 2 and the cable crimping terminal integrated cap 5 and the screw mechanism provided at both ends of the insulating tube 3 allow the screw tightening terminal integrated cap 2 and the cable crimping terminal integrated cap 5 to be connected to the insulating tube 3. Secure to both ends. At this time, an adhesive or the like may be used so as to ensure fixation. A hole for passing a fuse element is provided near the center of the cap portion of the screw terminal integrated cap 2 and the cable crimp terminal integrated cap 5, and a conical shape slightly protruding from the bottom surface of the cap around the hole. It has a structure that can fuse the fuse element. Normally, the fuse element is formed by fixing the screw terminal integrated cap 2 and the cable crimp terminal integrated cap 5 to both ends of the insulating cylinder 3 and crimping the conical protrusion of the hole through which the fuse element passes. Is fixed to the cap and soldered from the outside, and the cable 4 is further crimped and connected, and the entire fuse except for the screw terminal portion and the cable covering portion is covered with a heat-shrinkable insulating material (not shown). The structure and material of the fuse element is a straight line with a silver-plated copper wire as a center line, and an upper steel wire around it, with a cross-sectional area ratio of 1: 1, silver as a skin material, and zinc or zinc-silver alloy as a core material A silver / zinc clad wire or a silver / zinc silver alloy clad wire is wound spirally. The screw fastening terminal portion of the screw fastening terminal integrated cap 2 is attached to a specific device or part in the engine room. However, depending on the installation conditions, as shown in FIG. In addition, the cable may be connected to both ends of the fuse using the cable crimp terminal integrated cap 5.
[0009]
【The invention's effect】
When the high-current packaging fuse with a cable according to the present invention is used in an automobile, it can be directly attached to a specific device or part in the engine room, so that it can be wired without going through a fuse box. Therefore, the fuse box can be reduced in weight, the cable can be shortened, and the main circuit can be simplified. The improvement of the heat resistance and fusing characteristics due to the improvement of the fuse element has dramatically improved the reliability, and in addition Contributes to cost reduction of the automobile.
[Brief description of the drawings]
FIG. 1 is a perspective view showing Example 1. FIG.
FIG. 2 is an exploded perspective view showing the first embodiment.
FIG. 3 is a perspective view showing another type of the first embodiment.
FIG. 4 is a plan view seen from the ground, showing the angle between the cable crimp terminal and the screw terminal part.
FIG. 5 is a cross-sectional view showing the arrangement of samples and the like in a combined aging test.
FIG. 6 is an exploded perspective view of a conventional large current fuse (cartridge type large current fuse).
FIG. 7 is a perspective view of a conventional large current fuse (insulator type large current fuse).
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Large current packaging fuse with a cable 2 Screw terminal integrated cap 3 Insulation tube 4 Cable 5 Cable crimp terminal integrated cap 6 Fuse element 7 Cartridge type large current fuse 8 Cover 9 Screw terminal 10 Housing 11 Insulator type large current fuse 12 Conical terminal 13 Insulator

Claims (3)

 In a fuse composed of an insulating cylinder, two or more strand structure fuse elements, and a pair of metal caps fixed to both ends of the insulating cylinder, the cap is integrated with the cable crimp terminal portion, and the cap and the cable crimp terminal portion are When there is a flat metal plate between them, the metal plate of the flat metal plate between the cap and the cable crimp terminal and the side of the cap are vertical, and one end of the cable is fixed to the cable crimp terminal The cable crimping terminal part is provided with a cable crimping terminal part that is integral with the cap so that the cable and the side surface of the cap are in the vertical direction, spiral grooves (male threads) are provided on both ends of the insulating cylinder, and the groove of the insulating cylinder is provided on the cap. A high-current packaging fuse with a cable having a rated voltage of 32 V or less, which is provided with a spiral groove (female screw) that fits together.  2. The large current packaging fuse with a cable according to claim 1, wherein one of the pair of metal caps is provided on one end of the metal plate so that the side surface of the cap is perpendicular to the metal plate, and is insulated from the cap. A large cable with a cable that has a spiral groove (female thread) that fits into the groove of the cylinder, and is replaced with a cap that has a through hole on the other end of the metal plate as a screw-tightening terminal and a screw-tightening terminal. Current packaging fuse.  The fuse element is composed of two stranded wires, one is a silver-plated copper wire, and the other is a silver / zinc clad wire using zinc as a core material and silver as an outer shell material. The packaging fuse for large currents with a cable according to claim 1 or 2.

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