JP5692010B2 - Terminal fitting - Google Patents

Description

  The present invention relates to a terminal fitting having an overcurrent protection function.

  As this type of terminal fitting, for example, the one described in Patent Document 1 below is known. The terminal fitting has a fuse cylinder in which an element is accommodated, and arc-extinguishing sand is filled in the fuse cylinder. When a current exceeding the allowable current flows through the element, the power supply circuit is interrupted by the element generating heat and fusing. At the time of this interruption, although arc discharge occurs between the remaining elements, the metal vapor of the vaporized element condenses on the surface of the arc-extinguishing sand, thereby cooling the arc and interrupting the arc discharge. Yes.

JP-A-2005-294103

  In order to condense the metal vapor of the element on the arc-extinguishing sand as described above, the element and the arc-extinguishing sand need to be in contact with each other. However, when the element is melted and vaporized, a gap is formed where the element is vaporized and disappears, and arc discharge occurs in the gap. Therefore, it is necessary to fill the arc-extinguishing sand by pouring arc-extinguishing sand into the generated gap at the same time as the gap is generated. For this purpose, a method of optimizing the particle size and shape of the arc-extinguishing sand and applying vibration to increase the filling rate of the arc-extinguishing sand is carried out, which hinders cost reduction of the fuse. Further, in order to prevent breakage due to arc heat, glass or ceramic having excellent heat resistance is often used as the material of the fuse cylinder, which is one factor in increasing the size of the terminal fitting.

  The present invention has been completed based on the above circumstances, and an object thereof is to realize cost reduction and size reduction in a terminal fitting having an overcurrent protection function.

  The present invention is a terminal fitting having an overcurrent protection function, comprising a terminal main body provided with a fusing part, arc-extinguishing sand in contact with the fusing part, and heat-resistant fibers, and containing the arc-extinguishing sand therein. It is characterized in that it comprises a housing member to be pressed and a pressurizing member that pressurizes the housing member so that the arc-extinguishing sand and the fusing part are brought into contact with each other by elastically covering the housing member.

  According to such a configuration, the arc-extinguishing sand and the melted portion are held in contact with each other by the pressure member, so that the particle size and shape of the arc-extinguishing sand are optimized, or vibration is applied to increase the filling rate of the arc-extinguishing sand. There is no need to add, and the cost can be reduced. In addition, since the arc-extinguishing sand is accommodated inside the accommodating member by the accommodating member made of heat-resistant glass fiber, the terminal fitting can be made smaller than when the accommodating member is made of glass or ceramic.

The following configuration is preferable as an embodiment of the present invention.
The terminal body may have a pair of conductive plates, and the fusing part may be formed integrally with each conductive plate in such a manner that these conductive plates are connected to each other so as to be conductive.
According to such a configuration, for example, a pair of conductive plates and a fusing part can be formed by punching a metal flat plate constituting the terminal body into a predetermined shape by pressing or the like. That is, each conductive plate and the fusing part can be formed integrally in advance, and the work of welding the fusing part to each conductive plate is not necessary.

The housing member is a glass cloth made of glass fiber formed into a cylindrical shape, and the gap between the glass fibers is smaller than the particle diameter of the arc-extinguishing sand. It is good also as a structure filled with the inside of an accommodating member.
According to such a configuration, the work of filling the arc-extinguishing sand becomes easy.

The pressurizing member may be a heat-shrinkable tube, and may be configured to have a hole having a smaller hole diameter than that of the arc-extinguishing sand.
According to such a configuration, it is possible to prevent the arc-extinguishing sand from flowing out and to prevent an increase in internal pressure when fusing the fusing part.

  According to the present invention, cost reduction and size reduction can be realized in a terminal fitting having an overcurrent protection function.

Plan view of terminal fitting AA line sectional view in FIG. BB sectional view in FIG. Plan view of terminal fitting before mounting heat shrink tube Top view of terminal body

<Embodiment>
An embodiment of the present invention will be described with reference to the drawings of FIGS. The terminal fitting 10 of this embodiment is a terminal fitting that is housed in a joint connector with an overcurrent protection function and has an overcurrent protection function. As shown in FIG. 1, the terminal fitting 10 includes a terminal connection portion 20 having a long hole 21, a wire connection portion 30 having a barrel 31 that is crimped to a core wire of an electric wire (not shown), and a terminal connection portion. 20 and a current interrupting part 40 arranged from the electric wire connecting part 30. The terminal connection part 20 is connected by, for example, tightening with a nut through a long hole 21 to a battery post erected on a battery (not shown). On the other hand, the electric wire connection part 30 is connected by caulking the barrel 31 to the core wire exposed by peeling off the insulation coating at the end of the electric wire.

  The terminal connection portion 20 is configured to include the first conductive plate 42 illustrated in FIG. 5, and the electric wire connection portion 30 is configured to include the second conductive plate 43 illustrated in FIG. 5. The first conductive plate 42 and the second conductive plate 43 are connected to each other by an element 41 formed narrower than these. The element 41, the first conductive plate 42, and the second conductive plate 43 constitute a terminal body TB. The terminal body TB is formed by punching a metal flat plate as a base material into a predetermined shape and then bending the second conductive plate 43.

  The element 41 has a crank shape and is bent at a right angle from the first connection piece 41A connected to the terminal connection portion 20, the second connection piece 41B connected to the wire connection portion 30, and the tip of the second connection piece 41B. And the third connection piece 41C connected to the tip of the first connection piece 41A. The connecting portion of the first connection piece 41A and the third connection piece 41C is circular. The third connection piece 41C is formed narrower than the first connection piece 41A and the second connection piece 41B, and has the smallest cross-sectional area and the highest resistance value among the elements 41. Therefore, when a current exceeding the allowable current flows through the element 41, the third connection piece 41C generates heat and is cut off, thereby cutting off the power supply circuit. When stress is applied to the element 41, the stress is relieved by elastically deforming the element 41.

  As shown in FIG. 3, the current interrupting unit 40 includes an element 41, arc-extinguishing sand 44 disposed around the element 41, a glass sleeve 45 covering the arc-extinguishing sand 44, and elastically covering the glass sleeve 45. The heat shrinkable tube 46 is provided. The glass sleeve 45 is a glass cloth made of glass fiber formed in a cylindrical shape, and the gap between the glass fibers is smaller than the particle diameter of the arc-extinguishing sand 44. As a result, the arc-extinguishing sand 44 is filled inside the glass sleeve 45 without flowing out. The heat shrinkable tube 46 pressurizes the glass sleeve 45 so that the arc extinguishing sand 44 and the element 41 are brought into contact with each other. For this reason, the arc-extinguishing sand 44 and the element 41 are always kept in contact. The heat-shrinkable tube 46 includes a hole (not shown) having a hole diameter smaller than the particle diameter of the arc-extinguishing sand 44.

  The present embodiment is configured as described above, and its operation will be described subsequently. First, a method for manufacturing the terminal fitting 10 will be briefly described. A glass sleeve 45 is externally fitted to the element 41, and the glass sleeve 45 is pierced while widening the gap between the glass fibers using a syringe or the like, and arc-extinguishing sand 44 is injected into the glass sleeve 45 from the tip of the syringe. Next, after the heat-shrinkable tube 46 is fitted on the glass sleeve 45, the heat-shrinkable tube 46 is contracted by heating. Then, the glass sleeve 45 condenses the arc-extinguishing sand 44 by receiving the pressing force of the heat shrinkable tube 46, the arc-extinguishing sand 44 is filled in the glass sleeve 45, and the arc-extinguishing sand 44 is in contact with the element 41. Held in a state. Thus, the terminal fitting 10 having an overcurrent protection function is manufactured.

  Next, the terminal connection part 20 of the terminal fitting 10 is connected to a battery post or the like, and the barrel 31 of the electric wire connection part 30 is crimped and connected to the core wire of the electric wire to constitute a power supply circuit. When the power supply circuit is energized and a current exceeding the allowable current flows through the terminal fitting 10, the third connection portion 41C having the highest resistance value generates heat and blows. At this time, although the internal pressure of the heat-shrinkable tube 46 is going to rise, the internal air escapes to the outside through the hole of the heat-shrinkable tube 46, so that the rise of the internal pressure can be prevented. In addition, although a gap is formed where the third connection portion 41C disappears, arc-extinguishing sand 44 flows into the gap due to the pressing force of the heat shrinkable tube 46 at the same time as the gap is formed. Can be filled with arc-extinguishing sand 44. Therefore, arc discharge can be interrupted.

  As described above, in the present embodiment, the terminal body TB provided with the element 41, the arc-extinguishing sand 44 in contact with the element 41, the glass sleeve 45 made of glass fiber and containing the arc-extinguishing sand 44, and the glass Since the structure includes the arc-extinguishing sand 44 and the heat-shrinkable tube 46 that pressurizes the glass sleeve 45 so as to contact the element 41 by elastically covering the sleeve 45, The element 41 is kept in contact, and it is not necessary to optimize the particle size and shape of the arc-extinguishing sand 44 or to increase the filling rate of the arc-extinguishing sand 44, thereby reducing the cost. Further, since the arc-extinguishing sand 44 is accommodated inside the glass sleeve 45 by the glass sleeve 45 made of heat-resistant glass fiber, the terminal fitting 10 is made more than accommodating the arc-extinguishing sand 44 using glass or ceramic. Easy to miniaturize.

  The terminal body TB has a pair of conductive plates 42 and 43, and the element 41 is integrally formed with each of the conductive plates 42 and 43 in such a manner that the conductive plates 42 and 43 are connected to each other so as to be conductive. Therefore, for example, the pair of conductive plates 42 and 43 and the element 41 can be formed by punching a metal flat plate constituting the terminal body TB into a predetermined shape by pressing or the like. That is, the conductive plates 42 and 43 and the element 41 can be integrally formed in advance, and the work of welding the element 41 to the conductive plates 42 and 43 becomes unnecessary.

  The gap between the glass fibers of the glass sleeve 45 is smaller than the particle diameter of the arc-extinguishing sand 44, and the arc-extinguishing sand 44 is filled into the glass sleeve 45 by widening the gap. Therefore, the work of filling the arc-extinguishing sand 44 becomes easy. In addition, since the heat shrinkable tube 46 has a hole having a hole diameter smaller than the particle diameter of the arc-extinguishing sand 44, the arc-extinguishing sand 44 is prevented from flowing out and an increase in internal pressure when the element 41 is melted is prevented. Can be prevented.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) Although the glass sleeve 45 is used as the housing member in the above embodiment, according to the present invention, any material may be used as long as it is a housing member made of heat-resistant fibers.

  (2) Although the heat-shrinkable tube 46 is used as the pressure member in the above embodiment, the pressure may be applied by tape winding according to the present invention.

  (3) Although the crank-shaped element 41 is illustrated in the above embodiment, according to the present invention, a straight-shaped element may be used.

10 ... Terminal fittings 41 ... Element (fused part)
42 ... 1st conductive plate 43 ... 2nd conductive plate 44 ... Arc-extinguishing sand 45 ... Glass sleeve (accommodating member)
46 ... Heat shrinkable tube (pressurizing member)
TB ... Terminal body

Claims (4)

A terminal fitting with an overcurrent protection function,
A terminal body provided with a fusing part;
Arc-extinguishing sand in contact with the fusing part,
A housing member made of heat-resistant fiber, housing the arc-extinguishing sand inside,
A terminal fitting comprising: a pressure member that pressurizes the housing member so as to bring the arc-extinguishing sand and the fusing part into contact with each other by elastically covering the housing member.   The terminal fitting according to claim 1, wherein the terminal body has a pair of conductive plates, and the fusing part is formed integrally with each conductive plate in such a manner that the conductive plates are connected to each other so as to be conductive.   The housing member is formed by forming a glass cloth made of glass fiber into a cylindrical shape, and the gap between the glass fibers is smaller than the particle diameter of the arc-extinguishing sand, and widens the gap. The terminal fitting according to claim 1 or 2, wherein the arc-extinguishing sand is filled in the housing member.   The terminal fitting according to any one of claims 1 to 3, wherein the pressurizing member is a heat-shrinkable tube and has a hole having a hole diameter smaller than a particle diameter of the arc-extinguishing sand.

Images