JP2015211218A - Circuit protection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circuit protection device for reducing thermal loss due to thermal imbalance, by arranging a plurality of resistance heating elements in a case so as to affect each other.SOLUTION: A circuit protection device includes a case 10, a resistor 30, a pair of electrodes 32 arranged on the opposite sides of the resistor, and a NTC thermistor having a negative temperature coefficient and including an input line 33 and an output line 34 led out, respectively, from the pair of electrodes. In no-load state, a resistor having a small resistance value, out of the NTC thermistor and resistor, becomes a major flow path of current, and a NTC thermistor having a large resistance becomes a minor flow path of current. In load state, heat of the resistor is transmitted, and a NTC thermistor having a resistance value smaller than that of the resistor becomes a major flow path of current, and the resistor becomes a minor flow path of current.

Description

  The present invention relates to a circuit protection device, and more particularly, a plurality of resistance heating elements inserted into a case thermally affect each other and reduce a thermal imbalance between the plurality of resistance heating elements. It is related with the circuit protection apparatus arrange | positioned in this way.

  When a power source is applied to an electronic product, a large amount of current instantaneously flows, which is referred to as inrush current. When an inrush current repeatedly flows into a circuit board mounted on an electronic product, the damage and deterioration of electronic components and semiconductor elements mounted on the circuit board may lead to shortened lifetime and reduced functionality, so additional circuit protection The device is mounted on the circuit board.

  A thermistor is known as one of such circuit protection elements. The thermistor is a resistance element whose resistance value is sensitively changed thermally, and has a characteristic that an electrical resistance value changes with a change in its own temperature or ambient temperature. A thermistor having a negative temperature coefficient among thermistors is referred to as an NTC thermistor (Negative temperature coefficient thermistor). Such an NTC thermistor decreases in resistance as the temperature of itself or the ambient temperature increases.

  Due to the characteristics of such an NTC thermistor, the NTC thermistor is utilized as an inrush current suppressing protection element. When the inrush current is reduced, the larger the NTC thermistor having a larger resistance value, the greater the effect. When the NTC thermistor having such a large resistance value is used, a great effect is exhibited in reducing the inrush current, but power loss and heat loss are continuously generated after the inrush current is reduced. Therefore, when reducing the inrush current through the NTC thermistor, it is preferable to use an NTC thermistor having a small resistance value.

  Moreover, in order to reduce the electric power and heat loss after reducing the inrush current, it is preferable to use an NTC thermistor having a large surface area or good heat dissipation characteristics.

  Patent Document 1 discloses a circuit protection element with improved heat dissipation characteristics. In this circuit protection element, a heat release characteristic is improved by inserting a disk-type heating resistor inside the case and filling the case with a filler. Patent Document 2 discloses a heat generation reducing electronic component in which a heat-generating electronic element is housed in a case and the heat dissipation characteristics are improved by filling the inside of the case with resin-type cement.

  However, such circuit protection elements can individually have good heat dissipation characteristics. However, when a large number of such circuit protection elements are mounted on a circuit board, there is a thermal imbalance between the protection elements. Power and heat loss still occur. That is, when an inrush current flows into a circuit board on which a large number of circuit protection elements are mounted, the resistance value or thermal characteristic differs for each circuit protection element, and current flows intensively only to a specific circuit protection element. On the contrary, the problem that almost no current flows occurs. As a result, a specific circuit protection element may not perform a circuit protection function, and a thermal imbalance between the circuit protection elements occurs, resulting in power or heat loss. For example, when an inrush current is applied to a circuit board on which an NTC thermistor having a resistance value of 5Ω and an NTC thermistor having a resistance value of 5.1Ω are mounted, the resistance of the NTC thermistor having a resistance value of 5Ω is 0. The temperature rises to 130 ° C while decreasing to 2Ω, but the NTC thermistor whose resistance value is 5.1Ω rises to about 45 ° C while the resistance decreases slightly to 4Ω, and the difference in resistance value is small A significant thermal imbalance between the thermistors, which becomes more severe over time.

  Also, due to the increase in size of electronic products and the appearance of high-quality display devices such as OLED and UHD, a large amount of current flows through the electronic products. For this reason, it is required to employ circuit protection elements having a low resistance value. However, a circuit protection element using a conventional NTC thermistor has a limit in reducing the resistance value. That is, in order to reduce the resistance, the size of the NTC thermistor must be increased. However, as the size of the NTC thermistor increases, the manufacturing unit price increases geometrically, so the size of the NTC thermistor is simply increased. There is a limit to reducing resistance.

Korean Patent Publication 2012-9303 Japanese Patent Publication No. 2007-103687

  The present invention is for solving the above-described problems, and a plurality of resistance heating elements are arranged in a case so as to thermally influence each other, thereby reducing thermal loss due to thermal imbalance. The main object is to provide an obtained circuit protection device.

  Another object of the present invention is to arrange an NTC thermistor and a general resistor in the case so that the heat generated by the general resistor affects the NTC thermistor, thereby causing thermal loss due to thermal imbalance. It is an object of the present invention to provide a circuit protection device capable of reducing the above.

  Another object of the present invention is to connect an NTC thermistor and a general resistor in the case, and in the no-load state, the general resistor becomes the current main flow path, and in the load state, the NTC thermistor becomes the current main flow path. It is an object of the present invention to provide a circuit protection device having improved stability and extended life.

  Another object of the present invention is to provide a circuit protection device having a relatively small combined resistance value by efficiently connecting a plurality of resistance heating elements in a case.

  Another object of the present invention is to provide a circuit protection device that effectively implements connection and arrangement between a plurality of resistance heating elements in a case and can reduce the installation space on a circuit board.

  To achieve the above object, a circuit protection device of the present invention includes a case, a plate-like first resistance heating element, and a pair of electrodes installed on both sides of the first resistance heating element. And a thermistor including an input line and an output line respectively drawn from the pair of electrodes, a resistor including a current input line and an output line housed in the case, an input line of the thermistor, and the resistor An input connection part that connects the input line, an output connection part that connects the output line of the thermistor and the output line of the resistor, one end is coupled to the input connection part, and the other end is outside the case The extended first lead wire includes one end coupled to the output coupling portion, the other end coupled to the outside of the case, the thermistor including an NTC thermistor, and the resistor Body A winding resistor having a resistance value smaller than that of the NTC thermistor, the NTC thermistor and the winding resistor being arranged adjacent to each other so as to thermally influence each other, and in an unloaded state, the NTC thermistor and Among the winding resistors, the winding resistor having a small resistance value is a major flow path for current, and the NTC thermistor having a large resistance value is a minor flow path for current. In a load state, heat of the winding resistor is transmitted. The NTC thermistor having a resistance value smaller than the resistance value of the winding resistor is configured to be a major flow path for current, and the winding resistor is a minor flow path for current, and the winding resistor and the The thermal imbalance between the NTC thermistor and the NTC thermistor is eliminated.

  In addition, the winding resistor is configured in a rod shape and disposed at the center of the plate-shaped NTC thermistor, and the longitudinal center line of the winding resistor is disposed substantially parallel to the NTC thermistor. It is characterized by that.

  According to the circuit protection device of the present invention, the plurality of resistance heating elements are arranged in the case so as to thermally influence each other, and thermal loss due to thermal imbalance can be reduced.

  Further, according to the circuit protection device of the present invention, the NTC thermistor and the general resistor are connected and arranged in the case so that the heat generated by the general resistor affects the NTC thermistor, thereby causing a thermal imbalance. Thermal loss can be reduced.

  Further, according to the present invention, the NTC thermistor and the general resistor are connected in the case, and the general resistor becomes a main flow path for current in the no-load state, and the NTC thermistor becomes the main flow path for current in the load state. By configuring as described above, it is possible to realize a circuit protection device with improved stability and extended life.

  In addition, according to the present invention, it is possible to implement a circuit protection device having a relatively small combined resistance value by efficiently connecting a plurality of resistance heating elements in the case.

  In addition, according to the present invention, it is possible to provide a circuit protection device that can reduce the installation space in the circuit board by effectively realizing the connection and arrangement between the plurality of resistance heating elements in the case.

It is a perspective view of Example 1 of the circuit protection device concerning the present invention. It is sectional drawing which follows the AA line of FIG. It is sectional drawing which follows the BB line of FIG. It is a perspective view in the state where the circuit protection element was stored in the case in Example 1 of the circuit protection device concerning the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a circuit protection device according to a first embodiment of the present invention in a state in which a filler is filled after a circuit protection element is accommodated in a case. It is the figure which showed the flow of the electric current of the no-load state in Example 1 of this invention. It is the figure which showed the flow of the electric current of the load state in Example 1 of this invention. It is a perspective view of Example 2 of the circuit protection apparatus which concerns on this invention. It is sectional drawing which follows the AA line of FIG. It is sectional drawing which follows the BB line of FIG. It is a perspective view in the state where the circuit protection element was stored in the case in Example 2 of the circuit protection device concerning the present invention. In Example 2 of the circuit protection apparatus which concerns on this invention, after a circuit protection element is accommodated in a case, it is a perspective view of the state with which the filler was filled.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  The first embodiment of the present invention includes a case 10, a thermistor 20, and a resistor 30.

  Referring to FIG. 1, the case 10 includes both side walls 11, a rear wall 12, a front wall 13, and a bottom wall 14, and an accommodation groove 15 in which the thermistor 20 and the resistor 30 are accommodated is formed. Is released. The front wall 13 is formed with a guide groove 16 that guides a lead wire to be described later.

  2 and 3, the thermistor 20 includes a resistance heating element 21, a pair of electrodes 22 installed on both sides of the resistance heating element 21, and an input line 23 and an output line drawn from the pair of electrodes 22, respectively. 24, which are coated with a coating material 25.

  The resistor 30 includes a resistor 31, a pair of electrodes 32 installed on both sides of the resistor 31, and an input line 33 and an output line 34 drawn from the pair of electrodes 32, respectively. 35.

  As shown in FIGS. 1 to 3, the input line 23 of the thermistor 20 and the input line 33 of the resistor 30 are connected by an input connecting part 40. Such an input connecting part 40 can also be constituted by a clamping device or the like, and the input line 23 of the thermistor 20 and the input line 33 of the resistor 30 can be connected together.

  Similarly, the output line 24 of the thermistor 20 and the output line 34 of the resistor 30 are connected by an output connecting part 50. Such an output connecting part 50 can also be constituted by a clamping device or the like, and the output line 24 of the thermistor 20 and the output line 34 of the resistor 30 can be connected together.

  On the other hand, a first lead wire 60 for applying power to the thermistor 20 and the resistor 30 is provided. One end of the lead wire 60 is coupled to the input connecting portion 40 and the other end is connected to the case 10. It is extended outside through the guide groove 16. In addition, a second lead wire 70 is provided to guide the current flowing out from the thermistor 20 and the resistor 30, and one end of the second lead wire 70 is coupled to the output connecting portion 50, The other end is extended to the outside through the guide groove 16 of the case 10.

  The case 10 is filled with the filler 80 in a state where the thermistor 20 and the resistor 30 are accommodated. The filler 80 only supports the thermistor 20 and the resistor 30 inside the accommodation groove 15. Instead, heat dissipation from the thermistor 20 and the resistor 30 is effectively performed. Therefore, as the filler 80, it is preferable to use a material excellent in heat dissipation characteristics.

  4 and 5 are diagrams showing an assembling process of the first embodiment of the circuit protection device according to the present invention. First, the case 10, the thermistor 20, and the resistor 30 are provided. The thermistor 20 and the resistor 30 are connected by an input connecting portion 40 and an output connecting portion 50, and a first lead wire 60 and a second lead wire 70 are coupled to the connecting portions 40, 50, respectively.

  In this state, as shown in FIG. 4, the thermistor 20 and the resistor 30 are accommodated in the accommodation groove 15 of the case 10. At this time, the end portions of the first lead wire 60 and the second lead wire 70 are respectively extended to the outside through the guide grooves 16.

  Thereafter, the accommodating groove 15 of the case 10 is filled with the filler 80, and the circuit protection device is completed. The circuit protection device thus completed is mounted on the circuit board and serves to limit the inrush current.

  On the other hand, in this embodiment, the thermistor 20 is an NTC thermistor having a plate shape as a whole, and the resistor has a rod shape as a winding resistor. It is preferable that the NTC thermistor and the winding resistor have an arrangement relationship that can reduce the overall size while the heat transfer is performed well. More preferably, the area is wide. In particular, the winding resistor is disposed at the center of the NTC thermistor, and the longitudinal center line of the winding resistor is disposed substantially parallel to the NTC thermistor. This is because not only the size of the circuit protection device is reduced, but also the thermistor 20 and the resistor 30 thermally affect each other and reduce the thermal imbalance. That is, when a current flows through the thermistor 20 and the resistor 30, they will generate heat, but heat transfer is performed from the one that generates a large amount of heat to the one that generates a small amount of heat, thereby reducing the thermal imbalance between the two. Can be resolved.

  In addition, the thermistor 20 and the resistor 30 can have the same resistance value or different resistance values. Regardless of the resistance value, since the thermistor 20 and the resistor 30 have a parallel connection structure, the combined resistance value is smaller than the resistance value of the thermistor 20 and the resistance value of the resistor 30. Therefore, it is possible to implement a circuit protection device having a relatively small combined resistance value that is difficult to implement with the thermistor 20 and the resistor 30 alone. In general, the resistance value of an NTC thermistor decreases as the size thereof increases, while the unit price increases as the size increases. Therefore, as in this embodiment, the NTC thermistor can be connected in parallel with the winding resistance value to reduce the thermal imbalance between them, and the circuit protection having a relatively small combined resistance value at low cost. An apparatus can be implemented. Also, due to the increase in size of electronic products and the appearance of high-quality display devices such as OLED and UHD, a large amount of current flows through the electronic products. For this reason, it is required to employ circuit protection elements having a low resistance value. However, this requirement can be addressed by the present invention.

  In particular, when the thermistor 20 and the resistor 30 have different resistance values, the heat generated from the circuit protection element having a small resistance value out of the thermistor 20 and the resistor 30 is transferred to the circuit protection element having a large resistance value. The resistance change of the circuit protection element having a large value is promoted.

  For example, as shown in FIG. 6, when an inrush current is applied to a circuit board on which an NTC thermistor having a resistance value of 5Ω and a resistor having a resistance value of 1Ω are mounted, these combined resistance values are 0. In the initial state (in this specification, this state is referred to as a “non-load state”), the resistor 30 having a small resistance value is a major flow path, that is, a major current. An NTC thermistor having a large resistance value becomes a minor flow path, that is, a minor current path (thin arrow in FIG. 6). Thus, a temporary thermal imbalance occurs between the NTC thermistor and the resistor, but such thermal imbalance is reduced and eliminated over time. This is because the heat generated from the resistor is transferred to the NTC thermistor, and the resistance value of the NTC thermistor rapidly decreases, so the amount of current flowing through the NTC thermistor also increases. As a result, more heat is generated in the NTC thermistor. , The thermal imbalance between the NTC thermistor and the resistor is reduced and eliminated. In this specification, the thermal equilibration state in which the thermal imbalance is reduced or eliminated is referred to as a “load state”. Actually, the combined resistance in the load state (thermal equilibrium state) was 0.375Ω.

  As shown in FIG. 7, in the load state (thermal equilibrium state), the resistance value of the resistor is 1Ω, the resistance value of the NTC thermistor is as low as 0.6Ω, and the NTC thermistor having a small resistance value is a major flow path. That is, a resistor having a large resistance value in the major current path (thick arrow in FIG. 7) becomes a minor flow path, that is, a minor current path (thin arrow in FIG. 7), and current path transition occurs. Can be confirmed. In this way, the NTC thermistor and the general resistor are connected and arranged in the case, and the general resistor becomes the current main flow path in the no-load state, and the NTC thermistor becomes the current major flow path in the loaded state. As a result, it is possible to implement a circuit protection device with improved stability and extended life.

  Next, a second embodiment of the present invention will be described with reference to the drawings.

  Similarly to the first embodiment, the second embodiment also includes a case 10, the thermistor 20, and a resistor 30. Therefore, the same reference numerals are used for the same components, and detailed descriptions thereof are omitted. The difference between the first embodiment and the second embodiment is the connection structure between the thermistor 20 and the resistor 30.

8 to 12, the circuit protection device according to the second embodiment includes a connecting portion 40 ″ that connects the output line 34 of the resistor 30 and the input line 23 of the thermistor 20. Such a connecting portion. The circuit protection device according to the second embodiment is connected to the input line 33 of the resistor 30 and connected to the other through a separate clamping device or connection means. One end is connected to the first lead wire 60 ′ extending outside through the guide groove 16 of the case 10, one end is connected to the output line 24 of the thermistor 20, and the other end is connected to the outside via the guide groove 16 in the case 10. The second lead wire 70 'is extended to the resistor 30. Here again, the connection between the resistor 30 and the input line 33 and the connection between the thermistor 20 and the output line 24 are performed by a separate clamping device or connection means. Also to do through On the other hand, also in the second embodiment, the thermistor 20 is an NTC thermistor 20 having a large plate-like overall resistance value, and the resistor 30 has a small resistance value. Preferably, the longitudinal center line of the winding resistor is arranged substantially parallel to the NTC thermistor, so that the thermal imbalance between the NTC thermistor 20 and the resistor 30 is achieved. Can be eliminated.

  In addition, the thermistor and the resistor can have the same resistance value or different resistance values.

DESCRIPTION OF SYMBOLS 10 Case 20 Thermistor 30 Resistor 40 Input connection part 50 Output connection part 60, 60 '1st lead wire 70, 70' 2nd lead wire 80 Filler

Claims (2)

Case and
A plate-like first resistance heating element, a pair of electrodes installed on both sides of the first resistance heating element, and an input line and an output line respectively drawn from the pair of electrodes are accommodated in the case The thermistor,
A resistor housed in the case, comprising a current input line and an output line;
An input connecting part for connecting the input line of the thermistor and the input line of the resistor;
An output connecting portion for connecting the output line of the thermistor and the output line of the resistor;
A first lead wire having one end coupled to the input connecting portion and the other end extending outside the case;
One end coupled to the output connecting portion, and the other end includes a second lead wire extending outside the case;
The thermistor includes an NTC thermistor, and the resistor includes a winding resistor having a smaller resistance value than the NTC thermistor, and the NTC thermistor and the winding resistor are adjacent to each other so as to thermally influence each other. Arranged,
Of the NTC thermistor and the winding resistor, the winding resistor having a small resistance value is a major flow path for current, and the NTC thermistor having a large resistance value is a minor flow path for current. The NTC thermistor having a resistance value smaller than the resistance value of the winding resistor is transferred to the major resistance path of the current, and the winding resistor becomes the minor flow path of the current. The thermal imbalance between the winding resistor and the NTC thermistor is eliminated.
A circuit protection device. The winding resistor is configured in a rod shape and disposed in the center of the plate-shaped NTC thermistor, and the longitudinal center line of the winding resistor is disposed substantially parallel to the NTC thermistor. ,
The circuit protection device according to claim 1.

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