JP2019079742A - Surge protection apparatus - Google Patents

Abstract

To provide a surge protection apparatus that can suitably protect an electronic device from a switching surge in a relay and a lightning surge.SOLUTION: A surge protection apparatus includes two input terminals connected to a power supply, two output terminals respectively connected to both ends of an electromagnetic coil of a relay, lightning surge protection means connected between the two input terminals and acting on a lightning surge intruding from the two input terminal sides, and switching surge protection means connected between the two output terminals on the two output terminals side of the lightning surge protection means and acting on a switching surge generated in the electromagnetic coil.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a surge protection device.

  Relays are incorporated in signal devices used for railways, roads, and traffic such as aviation. The relay includes an electromagnetic coil and a contact terminal, and opens and closes the contact terminal by supplying a current to the electromagnetic coil. When the contact terminals are opened and closed, a back electromotive force is generated in the electromagnetic coil, and a switching surge (also called back electromotive force surge) is generated. In addition, surges that can not be completely removed frequently occur due to contact junction noise, contact switching noise, chattering, and the like at each switching. In order to prevent such a surge from reaching the signal device and destroying the signal device or causing a malfunction of the signal device, the relay is usually provided with a surge protection element.

  On the other hand, in electronic devices such as communication devices, lightning surges or induced lightning surges (hereinafter referred to simply as lightning surges and induced lightning surges as lightning surges) caused by direct lightning or induced lightning invade the electronic devices. It may be destroyed or malfunction may occur. Therefore, a surge protection element is provided in the electronic device.

JP 2002-270331 A

  In recent years, it has been a problem that a lightning surge causes destruction or malfunction of a signal device due to an increase in occurrence of lightning. The surge protection element provided in the relay also has the effect of preventing a lightning surge from intruding into the signal device. However, the surge protection device may be deteriorated by the surge generated frequently in the relay. In this case, destruction of the signal apparatus or malfunction may occur without being able to prevent penetration of the lightning surge. Such a problem may occur not only in the signal device but also in the electronic device provided with the relay, but in particular, if the signal device used for traffic is destroyed or malfunctioned, it causes traffic confusion. Is a big social problem.

  The present invention has been made in view of the above, and an object of the present invention is to provide a surge protection device capable of suitably protecting an electronic device from a switching surge in a relay and a lightning surge.

  In order to solve the problems described above and to achieve the object, a surge protection device according to an aspect of the present invention includes two input terminals connected to a power supply and two connected to both ends of an electromagnetic coil of a relay. A lightning surge protection means connected between an output terminal and the two input terminals and acting on a lightning surge intruding from the two input terminal sides, and the two output terminal sides with respect to the lightning surge protection means And switching surge protection means connected between the two output terminals and acting on the switching surge generated by the electromagnetic coil.

In the surge protector according to one aspect of the present invention, the lightning surge protector includes a first surge protector, and the switching surge protector includes a second surge protector and the second surge protector on the anode side. A first diode connected in series, and a second diode in which the second surge protection device is connected in series on the anode side on the opposite side of the first diode with respect to the second surge protection device, Assuming that the operation start voltage of the first surge protection device is V1, the reverse breakdown voltage of the first and second diodes is Vd, and the operation start voltage of the second surge protection device is V2, the following equations (1), 2)
Vd + V2> V1 (1)
V2 <V1 (2)
It is characterized in that

  The surge protection device according to one aspect of the present invention is characterized in that the first surge protection element is a discharge element or a varistor.

  The surge protection device according to one aspect of the present invention is characterized in that the second surge protection element is a discharge element, a varistor or a zener diode.

  A surge protection device according to one aspect of the present invention is characterized by comprising a casing that is made of a resin having insulating properties and heat resistance, and that accommodates the lightning surge protection means and the switching surge protection means.

  The surge protection device according to one aspect of the present invention is characterized in that a resin having insulation and heat resistance is filled between the lightning surge protection means and the switching surge protection means and the casing.

  ADVANTAGE OF THE INVENTION According to this invention, it is effective in the ability to protect an electronic device suitably from the switching surge in a relay, and a lightning surge.

FIG. 1 is a circuit diagram of a surge protection device according to an embodiment. FIG. 2 is a schematic view of an example of a unitized surge protection device. FIG. 3 is an exploded view of the surge protection device shown in FIG. FIG. 4 is a view for explaining a method of incorporating the surge protection device shown in FIGS.

  Hereinafter, an embodiment of a surge protection device according to the present invention will be described in detail with reference to the drawings. The present invention is not limited by this embodiment. Further, in the drawings, the same or corresponding elements are appropriately denoted by the same reference numerals.

  FIG. 1 is a circuit diagram of a surge protection device according to an embodiment. The surge protection device 100 includes two input terminals 11a and 11b, two output terminals 12a and 12b, a first surge protection element 13 serving as a lightning surge protection means, and a second surge protection element that constitutes a switching surge protection means. 14 and at least a first diode 15 and a second diode 16.

  The input terminals 11a and 11b are connected to a power supply 10 which is a DC power supply. Specifically, the input terminal 11 a is connected to the positive electrode side of the power supply 10 via the switch 30, and the input terminal 11 b is connected to the negative electrode side of the power supply 10.

  The output terminals 12 a and 12 b are connected to both ends of the electromagnetic coil 41 of the relay 40 respectively. The output terminal 12a is connected to the input terminal 11a, and the output terminal 12b is connected to the input terminal 11b. The relay 40 has a contact terminal 42.

  The first surge protection element 13 is, for example, a discharge element such as an arrester or a varistor, but is an arrester in the present embodiment. The first surge protector 13 is connected between the input terminals 11a and 11b.

  The second surge protection element 14 is, for example, a discharge element, a varistor, or a zener diode, but in the present embodiment is a zinc oxide varistor. One end of the second surge protection element 14 is connected to the anode side of the first diode 15, and the second surge protection element 14 and the first diode 15 are connected in series to constitute a switching surge protection means. There is. The cathode of the first diode 15 is connected to the output terminal 12a, and the other one terminal of the second surge protector 14 is connected to the output terminal 12b. Thus, the switching surge protection means is connected between the output terminals 12a and 12b on the side of the output terminals 12a and 12b relative to the first surge protection element 13.

  The second diode 16 is connected to the anode side of the second diode 16 on the opposite side of the first diode 15 with respect to the second diode 14 and the cathode is connected to the input terminal 11b. That is, one terminal of the second surge protection element 14 is connected to the anode side of the first diode 15, and the other terminal is connected to the anode side of the second diode 16.

  Next, the operation of the relay 40 will be described. When the switch 30 is switched from the off state to the on state, current flows from the power supply 10 via the input terminal 11a, the output terminal 12a, the electromagnetic coil 41, the output terminal 12b, the second diode 16, and the input terminal 11b. Thereby, the electromagnetic coil 41 generates a magnetic force. The two arms of the contact terminal 42 are attracted to both ends of the electromagnetic coil 41 by the magnetic force, and the contact terminal 42 changes from the open state to the closed state. When the switch 30 is turned off, the contact terminal 42 is opened. Depending on the open / close state of the relay 40, the electronic device equipped with the relay 40 or connected to the relay 40 is controlled.

  Next, the operation of the first surge protector 13 which is an arrester will be described. The first surge protection element 13 exerts a surge protection function against the bipolar lightning surges S1 and S2 that have entered from the input terminals 11a and 11b. Specifically, no current flows in the state where the voltage of the normal power supply 10 is applied to the first surge protection element 13, but when lightning surges S1 and S2 having a voltage higher than the operation start voltage enter Start the discharge to bypass the lightning surges S1 and S2. As a result, the first surge protector 13 protects the relay 40 from the lightning surges S1 and S2.

  Next, the operation of the second surge protector 14 which is a zinc oxide varistor, and the first diode 15 will be described. The second surge protection element 14 and the first diode 15 exert a surge protection function on the switching surge S3 generated in the relay 40. Specifically, when the switch 30 is switched from the on state to the off state, a back electromotive force is generated by the self-induction function of the electromagnetic coil 41 of the relay 40, and the switching surge S3 is generated. A switching surge S3 of a voltage equal to or greater than the sum of the operation start voltage of the second surge protection element 14 and the forward voltage of the first diode 15 is formed by the second surge protection element 14, the first diode 15, and the electromagnetic coil 41. Energy is consumed and eventually absorbed by these resistance components as it flows through the loop.

  That is, even when the lightning surges S1 and S2 and the switching surge S3 are separately introduced or generated, the surge protection device 100 exerts a protective action against these surges.

  As described above, according to the surge protection device 100, the lightning surges S1 and S2 and the switching surge S3 can suitably protect the electronic device provided with the relay 40 or connected to the relay 40.

  Since the first surge protector 13, the second surge protector 14 and the first diode 15 are connected in parallel, the lightning surges S 1 and S 2 are used as the second surge protector 14 and the first diode 15. Flow and / or switching surge S3 may also flow to the first surge protector 13.

Therefore, assuming that the operation start voltage of the first surge protection element 13 is V1, the reverse withstand voltage of the first diode 15 and the second diode 16 is Vd, and the operation start voltage of the second surge protection element 14 is V2, the following formula ( 1), (2)
Vd + V2> V1 (1)
V2 <V1 (2)
It is preferable that By satisfying the equation (1), the lightning surges S1 and S2 easily flow only to the first surge protection element 13 side. Further, by satisfying the equation (2), the switching surge S3 easily flows only to the second surge protection element 14 and the first diode 15 side. As a result, the first surge protection device 13 can be easily designed optimally for the lightning surges S1 and S2, and the second surge protection device 14 and the first diode 15 can be easily designed optimally for the switching surge S3. That is, it becomes possible to optimize separately for each of the lightning surge and the switching surge, and it is more preferable for both the lightning surge and the switching surge regardless of the magnitude relationship between the lightning surge and the switching surge. An operable surge protector 100 can be provided. For example, by setting Vd = 90 V, V1 = 90 V, and V2 = 56 V, formulas (1) and (2) hold.

  By unitizing the surge protection device 100 as shown in FIG. 2, it is possible to improve the workability of assembly, prevent erroneous wiring when attached to the relay 40, and improve productivity.

  The unitized surge protection device 100 includes a rectangular parallelepiped shaped housing 20 configured by molding a resin having insulating properties and heat resistance. The resin constituting the housing 20 is exposed to the open air environment, so it is required to be flame retardant while taking into consideration deterioration over time. Therefore, for example, it is preferable that the vertical combustion test grade in the UL94 standard has a flame retardancy corresponding to V-0. For example, as the resin constituting the housing 20, a polypropylene resin having a heat resistance temperature of 100 ° C. to 140 ° C. and a melting point of 168 ° C., a polycarbonate resin, a urea resin, a polybutylene terephthalate resin, etc. is used. A technique such as adding a glass frit is used to increase the Input terminals 11a and 11b and output terminals 12a and 12b project from both end surfaces of the housing 20, respectively. Further, a U-shaped groove 21 is formed in a plane substantially orthogonal to the both end faces. The groove 21 has a shape along the side surface of the electromagnetic coil 41 of the relay 40, and has an effect of facilitating the arrangement of the surge protector 100 in the vicinity of the electromagnetic coil 41.

  FIG. 3 is an exploded view of the surge protection device 100 shown in FIG. The input terminals 11a and 11b, the output terminals 12a and 12b, the first surge protection device 13, the second surge protection device 14, the first diode 15, and the second diode 16 are mounted on the circuit board 17. The input terminals 11 a and 11 b and the output terminals 12 a and 12 b are attached to the side surfaces orthogonal to the opposing side surfaces 17 a and 17 b of the circuit board 17. The input terminals 11a and 11b are flat terminals, and the output terminals 12a and 12b are hollow round terminals. At the roots of the input terminals 11a and 11b, insulating resins 18a and 18b such as silicone resin are formed by application.

  Moreover, the housing | casing 20 is shown in figure in the state which removed the lid | cover. The housing 20 is open at the side to which the lid is attached, and has a bottom surface opposite to the opening side. In the bottom surface, rectangular terminal holes 22a and 22b for inserting the input terminals 11a and 11b are formed. Further, on the inner surface on the opening side of the housing 20, substrate guide portions 23a and 23b provided with two protrusions are respectively provided.

  When assembling the unitized surge protection apparatus 100, first, each component is mounted on the circuit board 17, and the resins 18a and 18b are applied and formed. Subsequently, the circuit board 17 is inserted into the housing 20. At this time, the circuit board 17 is guided by inserting the side surfaces 17a and 17b of the circuit board 17 so as to pass between the two protrusions of the board guide portions 23a and 23b, respectively, and the input terminals 11a and 11b are square terminals. The holes 22a, 22b are smoothly inserted. Thereby, the first surge protector 13, the second surge protector 14, the first diode 15 and the second diode 16 are accommodated in the housing 20.

  Subsequently, a resin having insulating properties and heat resistance is poured into the housing 20, and the housing 20, and the first surge protection element 13, the second surge protection element 14, the first diode 15, and the second diode 16 are used. Fill in between. The resin to be filled is, for example, a urethane resin, an epoxy resin, a silicone resin, or a phenol resin as a base material, and an appropriate amount of silica powder, calcium carbonate powder, alumina powder or the like is added. Or a resin consisting only of the above base material. At this time, the resin 18a, 18b coated and formed at the root of the input terminal 11a, 11b closes the gap between the input terminal 11a, 11b and the edge of the rectangular terminal hole 22a, 22b, and functions so as not to leak the filled resin. Do. Thereafter, the filled resin is cured at a high temperature such as 80 ° C. or 120 ° C. or at a normal temperature. The cured resin prevents each element mounted on the circuit board 17 from falling off due to damage or vibration, and acts to protect each element from external dust, dust and moisture, and the reliability of the surge protection device 100 Raise. Thereafter, the lid is fixed to the housing 20. Terminal holes are formed in the lid, and the output terminals 12a and 12b are inserted into the terminal holes. Thereby, unitization of the surge protection device 100 is completed.

  Thereafter, as shown in FIG. 4, the round terminals 43a and 43b attached to the ends 41a and 41b of the winding constituting the electromagnetic coil 41 are inserted into the output terminals 12a and 12b, respectively, and provided on the circuit board 50. The surge protector 100 can be connected to the power supply 10 and the relay 40 by inserting the input terminals 11a and 11b into the pressure contact terminals 51a and 51b electrically connected to the power supply 10.

  As described above, by sealing and protecting each element constituting the surge protection device 100 with a heat-resistant material, even when each element generates heat, the influence on the other elements can be reduced.

(Example)
The surge protector 100 having the configuration shown in FIGS. 2 to 4 was manufactured, and its characteristics were measured. A 24 V DC power supply was used as the power supply 10. In addition, a relay 40 having an electromagnetic coil 41 with an inductance of 270 μ Henry was used. A gas arrester with an operation start voltage of 100 V was used as the first surge protection element 13. A zinc oxide varistor with an operation start voltage of 85 V was used as the second surge protection element 14. As the first diode 15 and the second diode 16, diodes having a reverse breakdown voltage of 42 V were used.

  A lightning surge resistance test was conducted on the produced surge protection device 100 in accordance with the provisions of IEC 61000-4-5 3rd Edition. As a test level, a conmode is used, and a surge voltage of 1.2 μ × 50 is superimposed from the surge tester at 4 kV at level 4 with respect to a DC voltage of 24 V from the power supply 10 and applied to the surge protector 100 As a result, no abnormality was found in each element. Furthermore, while the lightning surge resistance test was performed with the level of the surge voltage (superimposed voltage) set to 1 kV, 2 kV, 3 kV, 4 kV and 5 kV, a load test was performed to perform the switching operation of the relay 40 ten times at one minute intervals. As a result, no abnormality was found in each element or circuit board. Furthermore, although each element was removed from the circuit board and the electric characteristic evaluation as an element single-piece was performed, all the elements maintained the characteristic close to the initial characteristic before a test. Table 1 shows the test results. In Table 1, the absorbed voltage indicates the voltage absorbed by the first surge protection device 13. Further, as shown in Table 1, when the back electromotive force in the switching surge was 600 V, the second surge protector 14 started absorbing at 63 V at any of the superimposed voltages. In addition, the surge protection device 100 operated normally at any of the superimposed voltages, and no abnormality such as damage to the appearance was observed. In addition, when a protection circuit life test was performed on the surge protection device 100 at a switching surge output of 600 V, no damage was observed even in 250,000 continuous test results, and it was proved that the device could operate normally thereafter. .

  The present invention is not limited by the above embodiment. The present invention also includes those configured by appropriately combining the above-described components. Further, further effects and modifications can be easily derived by those skilled in the art. Thus, the broader aspects of the present invention are not limited to the above embodiments, but various modifications are possible.

DESCRIPTION OF SYMBOLS 10 Power supply 11a, 11b Input terminal 12a, 12b Output terminal 13 1st surge protection element 14 2nd surge protection element 15 1st diode 16 2nd diode 17 Circuit board 17a, 17b Side surface 20 case 21 Groove part 22a, 22b Square terminal hole 23a, 23b Board guide part 30 Switch 40 Relay 41 Electromagnetic coil 41a, 41b End 42 Contact terminal 43a, 43b Round terminal 50 Circuit board 51a, 51b Press-fit terminal receiving 100 Surge protector S1, S2 Lightning surge S3 Switching surge

Claims (6)

Two input terminals connected to the power supply,
Two output terminals respectively connected to both ends of the relay's electromagnetic coil;
Lightning surge protection means connected between the two input terminals and acting on a lightning surge intruding from the two input terminal sides,
Switching surge protection means connected between the two output terminals on the two output terminal sides of the lightning surge protection means and acting on the switching surge generated by the electromagnetic coil;
A surge protection device comprising: The lightning surge protection means comprises a first surge protection element,
The switching surge protection means includes a second surge protection element, and a first diode in which the second surge protection element is connected in series on the anode side.
In the opposite side of the first diode with respect to the second surge protection device, the anode side includes a second diode in which the second surge protection device is connected in series;
Assuming that the operation start voltage of the first surge protection device is V1, the reverse breakdown voltage of the first and second diodes is Vd, and the operation start voltage of the second surge protection device is V2, the following equations (1), 2)
Vd + V2> V1 (1)
V2 <V1 (2)
The surge protection device according to claim 1, wherein   The surge protection device according to claim 2, wherein the first surge protection element is a discharge element or a varistor.   The surge protection device according to claim 2 or 3, wherein the second surge protection element is a discharge element, a varistor or a zener diode.   The surge protection according to any one of claims 1 to 4, further comprising: a casing which is made of a resin having insulating properties and heat resistance, and which accommodates the lightning surge protection means and the switching surge protection means. apparatus. 6. A surge protection device according to claim 5, wherein a resin having insulation and heat resistance is filled between the lightning surge protection means and the switching surge protection means and the casing.

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