JP2007300735A - Overcurrent limiter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an overcurrent limiter, performing overcurrent protection of a protector having first and second signal terminals and a ground terminal, and surely protecting an apparatus from overcurrent, as well as eliminating the need for replacement after operation. <P>SOLUTION: The overcurrent limiter attached to a protector having first and second signal terminal members and performing overcurrent protection comprises a switch element taking insulation state during overcurrent, a first terminal member having one end connected with one end of the switching element, a second terminal member having one end connected with the other end of the switch element, and a case member attached between the first and second terminal members to cover the switch element. The limiter is attached between the first signal terminal member and the second signal terminal member, such that the first terminal member touches the first signal terminal member and the second terminal member touches the second signal terminal member. The switching element takes substantial insulation state during overcurrent, to insulate the first and second signal terminal members and performs overcurrent protection. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an overcurrent limiter, and more particularly, to an overcurrent limiter that performs overcurrent protection for a lightning arrester having a first signal terminal, a second signal terminal, and a ground terminal.

  Conventionally, a protector is provided between a signal cable and a communication device in order to protect the communication device from an overcurrent or a surge (see, for example, Patent Document 1).

  FIG. 8 shows a configuration diagram of an example of a conventional protector.

  The protector 400 mainly includes a lightning arrester ammunition 411, an overcurrent limiter 412, and a surge absorber 413.

  The lightning arrester ammunition 411 includes a ground plate 421, a first signal terminal member 422, a second signal terminal member 423, a movable member 424, a ground terminal member 425, an insulating member 426, a bolt 427, and a nut 428.

  A ground terminal member 425 is held on the ground plate 421. The first signal terminal member 422 and the second signal terminal member 423 are fixed to the ground plate 421 with bolts 427 and nuts 428 with the insulating member 426 interposed therebetween. Further, the movable member 424 is held in a movable state by the second signal terminal member 423.

  The overcurrent limiter 412 is configured to be soldered to a mandrel fixed to the case with the heat coil protruding from the case. As shown in FIG. 8A, the overcurrent limiter 412 has a first signal terminal in a state where the case is engaged with the first signal terminal member 422 and the heat coil is engaged with the second signal terminal member 443. It is inserted between the terminal member 422 and the second signal terminal member 423.

  At this time, a current flows from the second signal member 423 to the first signal terminal member 442 via the heat coil.

  When the current flowing through the heat coil is in an overcurrent state, the heat coil generates heat, and the solder that fixes the mandrel and the heat coil melts. When the solder which fixes the heat coil and the mandrel melts, the heat coil can be displaced in the axial direction of the mandrel. When the heat coil becomes displaceable, it is pressed into the case by the elastic restoring force of the first signal terminal member 422.

  As a result, the mandrel protrudes from the second signal terminal member 422 toward the movable member 424. When the mandrel protrudes from the second signal terminal member 422 toward the movable member 424, the movable member 424 is pressed toward the ground terminal member 425 by the mandrel, and the movable member 424 is connected to the ground terminal as shown in FIG. Contact member 425. When the movable member 424 contacts the ground terminal member 425, the first signal terminal member 422 and the second signal terminal member 423 are connected to the ground terminal member 424. As a result, the current is released to the ground, and the overcurrent state is eliminated.

The surge absorber 413 is mounted between the second signal terminal member 422 and the ground terminal member 425, and short-circuits the second signal terminal member 422 and the ground terminal member 425 when a surge occurs. The current was released to ground and surge was absorbed.
JP 2001-2111544 A

  However, the overcurrent limiter attached to the conventional protector has a so-called heat coil, and has a movable part, and thus has a problem of slow operation. Further, the heat coil has problems such as a complicated structure and poor productivity. Further, once the heat coil is operated, it does not return to its original state even if the overcurrent state is eliminated. After the overcurrent protection is performed, the heat coil needs to be replaced, and the maintainability is poor.

  The present invention has been made in view of the above points, and provides an overcurrent limiter that can reliably protect a device from overcurrent at high speed and that does not require replacement even after an overcurrent protection operation. Objective.

The present invention provides an overcurrent limiter that is attached to a protector having a first signal terminal member and a second signal terminal member and performs overcurrent protection. A first terminal member connected to one end of the switch element, a second terminal member having one end connected to the other end of the switch element, and a switch between the first terminal member and the second terminal member A case member mounted so as to cover the element, the first terminal member is in contact with the first signal terminal, and the second terminal member is in contact with the second signal terminal member. Is mounted between the signal terminal member and the second signal terminal member, and the first signal terminal member and the second signal terminal member are insulated by the switch element being in a substantially insulated state at the time of overcurrent, It is characterized by performing overcurrent protection.
The switch element is composed of a thermistor element.
Further, the first terminal member is engaged with a connecting portion connected to the switch element, a flange portion that is in surface contact with the first signal terminal member, and a positioning hole formed in the first signal terminal member. And the second terminal member includes a connecting portion connected to the switch element, a flange portion in surface contact with the second signal terminal member, and a second signal terminal member. The engaging portion that engages with the positioning hole formed in the first member is integrally formed, and the first terminal member and the second terminal member have the same shape. .
Further, the engaging portion has a step portion that engages around a positioning hole formed in the second signal terminal member.

  According to the present invention, the overcurrent limiter includes a switch element that is in an insulated state when overcurrent, a first terminal member having one end connected to one end of the switch element, and one end connected to the other end of the switch element. The second terminal member, and a case member mounted so as to cover the switch element between the first terminal member and the second terminal member, wherein the first terminal member is the first terminal member. The switch element is mounted between the first signal terminal member and the second signal terminal member so that the second terminal member contacts the signal terminal and the second terminal member contacts the second signal terminal member. Since the first signal terminal member and the second signal terminal member are insulated from each other by being in an insulated state and overcurrent protection is performed, no moving parts are required. Faster overcurrent protection and improved reliability Kill.

  FIG. 1 is an exploded perspective view of an embodiment of the overcurrent limiter of the present invention, and FIG. 2 is a perspective view of the embodiment of the overcurrent limiter of the present invention during assembly.

  The overcurrent limiter 100 according to the present embodiment includes a switch element 111, a first terminal member 112, a second terminal member 113, and a case 114.

  The switch element 111 is a switch element that enters a substantially insulated state when an overcurrent state occurs, and is configured of, for example, a thermistor element. As the thermistor element, a polymer PCT thermistor element (Positive Temperature Coefficient) made of a lump of polymer resin molded in a substantially plate shape can be considered. A polymer-based PTC thermistor is a device that has a positive temperature coefficient, and when the temperature of the element exceeds a predetermined temperature, the resistance value increases abruptly and becomes substantially insulated. The resistance value change of the polymer-based PTC thermistor element is reversible. When the power supply is turned off, the element temperature decreases, the original resistance value is restored, and conduction becomes possible. For this reason, it is not necessary to replace like a fuse.

  FIG. 3 shows a side view of the first terminal member 112.

  The first terminal member 112 is made of a conductive material, and has a configuration in which the connecting portion 121, the groove portion 122, the flange portion 123, and the engaging portion 124 are integrally formed by cutting.

  The connecting portion 121 has a substantially truncated cone shape, and its upper surface is abutted against one surface of the switch element 111 and soldered. The upper surface of the connection part 121 is formed to be smaller than the size of one surface of the switch element 111, and when the upper surface of the connection part 121 is abutted against one surface of the switch element 111, A wedge-shaped groove is formed between them.

  When the connection portion 121 and the switch element 111 are soldered, solder accumulates in the wedge-shaped groove, and the connection portion 121 and the switch element 111 can be reliably fixed. Further, it is possible to prevent the solder from wrapping around the side surface of the switch element 111.

  The bottom surface of the connecting portion 121 is connected to the flange portion 123 via the groove portion 122. A groove portion 122 is formed between the connection portion 121 and the flange portion 123. The groove portion 122 engages with a convex portion 131 formed on the inner peripheral side of the case 114.

  The flange portion 123 is formed in a substantially disk shape, and one surface side is connected to the connection portion via the groove portion 122, and the first signal terminal of the protector is in surface contact with the other surface.

  The engaging portion 124 has a substantially columnar shape, and is formed to protrude outward from the substantially center of the flange portion 123 in the direction of arrow A. The engaging part 124 includes a first engaging part 124a and a second engaging part 124b. The first engagement portion 124 a engages with the engagement portion 142 formed on the first signal terminal member 141.

  The second engagement portion 124b has a smaller diameter than the first engagement portion 124a, and the engagement portion formed in the first signal terminal member passes therethrough. Further, the second engaging portion 124b penetrates the engaging portion 152 formed in the second signal terminal member 151, and abuts against the upper end surface of the first engaging portion 124a and the end surface in the arrow A direction.

  Furthermore, the upper end surface of the second engagement portion 124 b and the end surface in the direction of arrow A abut against the movable terminal member 161.

  The second terminal member 113 has the same structure as the first terminal member 112, and the connecting portion 121 is soldered to the surface opposite to the surface to which the first terminal member 112 of the switch element 111 is soldered. The

  The first terminal member 112 and the second terminal member 113 have exactly the same structure. Therefore, since the 1st terminal member 112 and the 2nd terminal member 113 can be shared, manufacturing cost can be reduced.

[Case 114]
The case 114 includes case halves 114a and 114b, and is configured to have a substantially cylindrical shape by combining the case halves 114a and the case halves 114b.

  The case halves 114a and 114b have convex portions 131 formed in the vicinity of both end portions on the inner peripheral side. The protrusion 131 engages with the groove 122 of the first terminal member 112 and the groove 122 of the second terminal member 112 as described above. The case 114 is soldered with the first terminal member 112 and the second terminal member 113 to the switch element 111, and both end surfaces thereof are the flange portion 123 of the first terminal member 112 and the flange portion of the second terminal member 113. 123, and the protrusion 131 is attached so as to engage with the groove 122 of the first terminal member 112 and the second terminal member 113.

  By attaching the case 114, the switch element 111, the first terminal member 112, and the connection portion 121 of the second terminal member 113 are accommodated in the case 114 as shown in FIG. 2.

  In contrast to the heat coil, the overcurrent limiter 100 according to the present embodiment is configured so that the first signal terminal member 141 and the second signal terminal member 151 are insulated from each other at the time of overcurrent. The terminal member 141 side is protected from overcurrent flowing from the second signal terminal member 151.

[Application example]
Next, a protector to which the overcurrent limiter 100 is applied will be described.

  FIG. 4 shows a configuration diagram of an application example of the overcurrent limiter 100.

  This application example shows an example in which the overcurrent limiter 100 is attached to the protector 200.

  The protector 200 is configured such that the overcurrent limiter 100 and the surge absorber 300 are attached to the lightning arrester ammunition 211.

  The lightning arrester ammunition 211 has a ground terminal member 222 attached to the ground plate 221, and the first signal terminal member 141 and the second signal terminal member 151 are fastened to the insulating member 223 by bolts 2234 and nuts 225. The structure is fixed to the ground plate 221. A movable member 161 is fixed to the second signal terminal member 151 so as to be elastically deformable in the directions of arrows C1 and C2. The first signal terminal member 141 and the second signal terminal member 151 are configured to be elastically deformable in the directions of arrows B1 and B2. The overcurrent limiter 100 is mounted between the first signal terminal member 141 and the second signal terminal member 151, connected between the first signal terminal member 141 and the second signal terminal member 151, The surge absorbing device 300 is attached to the end of the lightning arrester bullet 211 and is connected between the second signal terminal member 151 and the ground plate 211.

  Next, the surge absorber 300 will be described.

  FIG. 5 is an exploded perspective view of the surge absorber 300, and FIG. 6 is a perspective view of the surge absorber 300 during assembly.

  The surge absorber 300 includes a circuit board 311, terminal members 312, 313 and 314, and a case 315.

  A ceramic gas arrester 321, a thyristor 322, and a resistor 323 are mounted on the circuit board 311, and terminal members 312, 313, and 314 are soldered around the circuit board 311.

  The case 315 includes case halves 331 and 332. The circuit board 311 and the terminal members 312, 313, and 314 are sandwiched between the case halves 331 and 332, positioned at predetermined positions, and stored.

  The case 315 has a rectangular planar shape and is formed with a U-shaped groove 341. The terminal members 312 and 313 are exposed and positioned on the side surface of the case 315. Further, the terminal member 314 is exposed and positioned on the inner peripheral side of the groove portion 314.

  The surge absorber 300 is mounted across the both sides of the lightning arrester bullet 211 with the groove 341 engaged with the end of the lightning arrester bullet 211. When the surge absorber 300 is mounted on the lightning arrester bullet 211, the terminal members 312 and 313 are in contact with the first signal terminal member 141, and the terminal member 314 is in contact with the ground terminal member 222.

  When the surge absorber 300 is attached to the lightning arrester bullet 211, the second signal terminal member 151 is elastically deformed in the directions of arrows C1 and C2. When the second signal terminal member 151 is elastically deformed in the directions of the arrows C <b> 1 and C <b> 2, the movable member 161 fixed to the second signal terminal member 151 is separated from the ground terminal member 222.

  The overcurrent limiter 100 is mounted between the first signal terminal member 141 and the second signal terminal member 151 while elastically deforming the first signal terminal member 141 in the direction of the arrow B1, and a first signal The elastic member is pressed against the second signal terminal member 151 by the elastic restoring force of the terminal member 141 and is held between the first signal terminal member 141 and the second signal terminal member 151. At this time, the interval between the first signal terminal member 141 and the second signal terminal member 151 is always maintained at a predetermined interval by the overcurrent limiter 100. In addition, the second engaging portion 124b of the overcurrent limiter 100 has the movable terminal member 161 when the overcurrent limiter 100 is mounted between the first signal terminal member 141 and the second signal terminal member 151. The height is set so as not to contact the ground terminal member 222. Thereby, the movable terminal member 161 and the ground terminal member 222 are always maintained in a non-contact state.

  FIG. 7 shows an equivalent circuit diagram of the protector 200.

  In the protector 200, the surge absorbing device 300 is disposed between the second signal terminal member 151 and the ground terminal member 222, and the above-described protection device 200 is interposed between the first signal terminal member 141 and the second signal terminal member 151. By connecting the overcurrent limiter 100, a circuit as shown in FIG. 7 is configured.

  At the time of overcurrent, the first signal terminal member 141 and the second signal terminal member 151 are disconnected due to the overcurrent limiter 100 being in a substantially insulated state. For example, the first signal terminal member 151 side is connected to the first signal terminal member 151 side. The overcurrent can be prevented from flowing to the signal terminal member 141 side. Thereby, the communication apparatus connected to the first signal terminal member 141 side can be protected from overcurrent.

  Further, when a surge voltage is generated, first, the thyristor 322 of the surge absorber 300 is turned on, and a current is passed from the ground terminal member 322 to the ground to absorb the surge voltage. Further, when the surge voltage rises, the ceramic gas arrester 321 of the surge absorber 300 is turned on, and a current is passed from the ground terminal member 322 to the ground to absorb the surge voltage.

  At this time, the thyristor 322 is a semiconductor element and can respond to the surge voltage at high speed. Further, the ceramic gas arrester 321 has a high withstand voltage, and can reliably absorb a surge voltage.

  Therefore, by using the surge absorbing device 300 of this application example, it is possible to respond to the surge voltage at a high speed and to cope with the high surge voltage.

  The resistor 323 is connected in series to the thyristor 322, and limits the current flowing through the thyristor 322.

  According to this embodiment, by using a thermistor element as the switch element 111, it is possible to cope with overcurrent at high speed. Further, since the overcurrent protection can be performed without moving the movable member 161, the reliability of the overcurrent protection can be improved. Even when overcurrent protection is applied, when the overcurrent state is released, the state automatically returns to the conductive state, so that maintenance is easy. Furthermore, it can be used by being mounted on the existing lightning arrester ammunition 211.

It is a disassembled perspective view of one Example of the overcurrent limiter of this invention. It is a perspective view at the time of the assembly of one Example of the overcurrent limiter of this invention. 3 is a side view of a first terminal member 112. FIG. 2 is a configuration diagram of an application example of an overcurrent limiter 100. FIG. 2 is an exploded perspective view of a surge absorber 300. FIG. It is a perspective view at the time of the assembly of the surge absorber 300. FIG. 3 is an equivalent circuit diagram of the protector 200. FIG. It is a block diagram of an example of the conventional protector.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Overcurrent limiter 111 Switch element, 112 1st terminal member, 113 2nd terminal member 114 Case, 114a, 114b Case half body 121 Connection part, 122 Groove part, 123 collar part, 124 Engagement part 124a 1st connection Joint part, 124b Second engagement part 131 Convex part 141 First signal terminal member, 151 Second signal terminal member, 161 Movable member 200 Arrestor 211 Arrester arrester 221 Ground plate, 222 Ground terminal member, 223 Insulating member 224 Bolt 225 Nut 300 Surge absorber 311 Circuit board, 312 to 314 Terminal member, 315 Case 321 Ceramic gas arrester, 322 Thyristor, 323 Resistance 331, 332 Case half 341 Groove

Claims (4)

In an overcurrent limiter that is mounted on a lightning arrester ammunition having a first signal terminal member and a second signal terminal member and performs overcurrent protection,
A switch element that becomes insulative when overcurrent; and
A first terminal member having one end connected to one end of the switch element;
A second terminal member having one end connected to the other end of the switch element;
A case member mounted between the first terminal member and the second terminal member so as to cover the switch element;
The first signal terminal member and the second signal terminal such that the first terminal member contacts the first signal terminal and the second terminal member contacts the second signal terminal member. It is mounted between the members,
An overcurrent limiter that performs overcurrent protection by insulating the first signal terminal member and the second signal terminal member when the switch element is in a substantially insulated state during the overcurrent. . The overcurrent limiter according to claim 1, wherein the switch element is a thermistor element. The first terminal member includes a connection portion connected to the switch element;
A flange that is in surface contact with the first signal terminal member;
An engaging portion that engages with a positioning hole formed in the first signal terminal member is integrally formed,
The second terminal member includes a connection portion connected to the switch element;
A flange that is in surface contact with the second signal terminal member;
An engaging portion that engages with a positioning hole formed in the second signal terminal member is integrally formed,
The overcurrent limiter according to claim 1, wherein the first terminal member and the second terminal member have the same shape. The overcurrent limiter according to claim 3, wherein the engaging portion has a stepped portion that engages around a positioning hole formed in the second signal terminal member.

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