EP3055869B1 - Compact overvoltage device which can be pre-assembled - Google Patents

Description

The invention relates to a compact, ready-to-use overvoltage protection device based on varistor with thermal separation unit, consisting of a two-sided laminated circuit board with Durchkontaktierungsbereich, wherein the at least one varistor connected to a first side of the laminated circuit board, in particular soldered and continue on the second side of the laminated circuit board provided with the plated-through area in operative connection separating slide, according to claim 1.

From the WO 2012/027255 A2 an overvoltage protection device with varistor unit and thermal separation device is previously known.

The local varistor unit is disconnected from the external circuit by a disconnect contact along a linear displacement axis by means of springs arranged in parallel under corresponding overload conditions. The production of the thermal separation point by soldering is possible in this solution of the prior art only in the built-in module. In addition, the mass of the overvoltage limiting component must be uniformly heated to provide safe and instantaneous isolation.

From the WO 2012/027193 A1 Another surge protection device with varistor unit, printed circuit board and separating device is shown. There, the varistor unit is mounted on a circuit board by soldering. The circuit board also has a via.

On the back of the circuit board, a special connection plate is firmly bonded to the plated-through holes with low-temperature solder. The connection plate has an M-shape and can be two separation modes realize. By provided in the connection plate tapers of the cross section should occur in the event of a short circuit, a melting. In addition, a pure thermal separation is possible when the melting temperature of the low-temperature solder is exceeded. However, the M-shaped configuration of the connection plate leads to very long conduction paths with corresponding inductances and a resulting disadvantageous influence on surge current events. In the region of the plated-through holes, mixing of the solder, which serves to fix the varistor, and the solder of the separating device, which has negative consequences for the separation properties.

Finally, from the above-described prior art of WO 2012/027193 A1 or belonging to the same patent family US 2012/0050936 A1 the need exists that the local separate shut-off valve must detach and move a portion of the short-circuit element. This assumes that the spring preload forces are sufficiently high. However, the same has the disadvantage that, in the usual operating case, considerable forces already act on the solder connection, which are problematic for the long-term behavior of a corresponding overvoltage protection device.

Furthermore, from the EP 1 077 452 A2 an overvoltage protection device with thermal cutting device is known in which a metal oxide varistor is provided on both sides with contact plates. On a first side is located on the contact plate, a connection bracket, which is materially connected there by means of low-temperature solder. In the case of reaching the melting temperature of the low-temperature solder, an insulating plate, which is biased by springs, pushes between the contact point and connecting bracket, so that a separation can be realized. The design of the local connection parts is very expensive. In addition, the realized overvoltage protection device has only a low surge current capability. Also in this solution, the execution of the solder connection of the thermal separation point is possible only in the built-in module. An inexpensive prefabrication with speaking electrical functional test is therefore not possible or very difficult.

From the foregoing, it is therefore an object of the invention to provide a further developed compact, prefabricatable overvoltage protection device on varistor with thermal separation unit, which manages with fewer parts, which is inexpensive manufacturable and the possibility exists to prefabricate all the essential functional elements including a known separation slide and mechanically and electrically connect in a soldering process.

The overvoltage protection device to be created should moreover ensure that the shock-current-resistant connection, which forms the separation point in the event of an overload, does not act on permanent forces during the normal operating time, which can lead to a deteriorated long-term behavior.

The object of the invention is achieved by the combination of features according to claim 1, wherein the dependent claims represent at least advantageous embodiments and developments.

Accordingly, the invention is based on a compact varistor-based overvoltage protection device with thermal cut-off unit which can be prefabricated in accordance with the task. The overvoltage protection device consists of a two-sided laminated printed circuit board with Durchkontaktierungsbereich. These may be conventional copper clad circuit boards on an insulating substrate, e.g. Epoxy material act.

The at least one varistor is preferably connected to a first side of the laminated printed circuit board by large-area soldering. Furthermore, on the second side of the laminated printed circuit board, a separating slide operatively connected to the plated-through area is provided. The plated-through holes are realized as known from the prior art, so-called VIAs. According to the invention, a first contact area, which is connected to the plated-through area, and a second contact area, which is remote therefrom via a separation distance, are formed on the second side of the laminated printed circuit board.

The shut-off valve bridges both contact surfaces and releases the separation distance in case of overload, i. the bridging of the contact surfaces is canceled by movement of the Abtrennschiebers.

According to the invention, the Abtrennschieber of a laminated printed circuit board material, wherein the contact surface bridging the conductive region of the printed circuit board material of the Abtrennschiebers has a first and a second soldering portion with befindlichem therebetween Stromengstelle.

The Stromengstelle can be formed by the fact that the surface of the printed circuit board Kupferkaschierung is reduced with the result that in case of overload, the remaining surface area is destroyed by appropriate heat development.

The separation slide can be formed in a preferred embodiment as a pan or rotary valve. The movement of the pivot or rotary slide takes place here in the plane of the circuit board, which receives the at least one varistor element.

In a preferred embodiment, the second contact surface is connected to a surface section for fastening, in particular soldering, an electrical connection element. This element can e.g. be a conductive contact angle, which leads to corresponding external terminals of a surge protection plug-in part.

In a preferred embodiment of the invention, the first side of the laminated circuit board has a substantially corresponding to the varistor surface laminated portion for the desired full-surface connection and for optimum heat transfer. The via region is integrated in this laminated portion. For the attachment of the varistor on the first side of the laminated circuit board together with the filling of the plated-through holes, conventional solder can be used.

In the case of the first contact surface located on the second side of the laminated printed circuit board, the through-contacting region hangs therewith, as already mentioned, together, but covered in the operating case, the corresponding contact surface of the Abtrennschieber preferably only the actual contact surface, but not the Durchkontaktierungsbereich. The contact area and the via area are preferably separated by solder resist, which prevents mixing of different solder types. It is therefore readily possible here to connect the contact surface area with the separation slide via a solder which has a correspondingly optimized melting temperature tailored to the separation case. This melting temperature is usually lower than the melting temperature of the solder connecting the varistor to the first side of the circuit board. Thus, after the varistor has been connected to the first side of the printed circuit board by soldering, in the next step the soldering of the separating slide with the corresponding contact surfaces can be carried out with a solder which has a lower melting temperature.

The base material of the circuit board and the Abtrennschiebers may consist of a plastic, hard paper, but also of a ceramic. A printed circuit board material based on epoxy resin is preferably used.

In addition, a soldering pad surface is preferably provided on the second side of the laminated printed circuit board outside the range of movement of the Abtrennschiebers, which serves to secure a releasing when heating lock button or a blocking pill.

The lock button or the blocking pill may also consist of a copper-clad circuit board material and is firmly bonded to the soldering pad.

In this case, the melting temperature of the bonding solder is chosen to be lower than the melting temperature of the solder, which serves to connect the Abtrennschiebers with the corresponding contact surfaces on the second side of the circuit board in this case.

Preferably, the compact surge protection device summarized above can be inserted into a housing of a plug-in part of the overvoltage protection device and is electrically connected to terminal contacts located there, in particular terminal plug contacts.

In the housing of such a male part a spring-biased bracket is arranged, which is on the one hand with the Abtrennschieber and on the other hand with a status display in operative connection.

The status indicator may be formed, for example, as a sliding surface which moves within a viewing window of the housing and releases different color coding sections. In a proper state, for example, the recognition of a green section in the viewing window. In the case of prior damage, e.g. a yellow section is released. In the case of thermal overload, a red area becomes visible.

The spring-biased bracket has in a preferred embodiment of the invention, a stop which bears against the lock button. After thermally induced release of the lock button or the blocking pill from the Lötstützpunktfläche then the spring-loaded bracket is the power side connected to the Abtrennschieber.

The locking button or the blocking pill moves in accordance with thermally induced loosening in this regard provided in the interior of the housing receiving surface. As a result of this release of motion, the status indicator performs a motion that releases the aforementioned yellow portion, so that it can be seen during normal maintenance or inspection that the overvoltage protection device was subject to a thermal load or previous damage.

Only in the case of releasing the lock button or the blocking pill spring preload acts on the separating tab on the Abtrennschieber. This means that in the usual case of operation, the solder joint between Abtrennschieber and corresponding contact surfaces on the second side of the circuit board are not subjected to a permanent force in Abtrennrichtung, which increases the reliability of a correspondingly realized overvoltage protection device and its long-term stability.

Inside the housing, in an embodiment of the invention, a recess for the leading reception of a club-like end pointing away from the contact surfaces of the separating slide is provided educated. By this guide recess of the desired Verschwenkweg the Abtrennschieber is secured, which can be additionally supported by a further contour design of the Abtrennschieber itself in conjunction with a guide recess in the housing interior. Preferably, the blocking button or barrier pill is connected to the solder pad surface with a solder melting at a first temperature and the separator gate is connected to a solder melting at a second temperature with the contact surfaces, the first melting temperature being lower than the second temperature. As a result, possible pre-damage can be signaled in conjunction with the above-described display unit and it is only then the spring biasing force on the Abtrennschieber effective when the case of previous damage has occurred.

The described housing for receiving the prefabricated overvoltage protection device preferably has a conventional flat rectangular or square shape with a housing bottom, from the underside terminal contacts extending, which engage in corresponding recesses of a base part. On the underside of the housing or in the housing bottom can still be present a recess which is penetrated by a pin which is part of the spring-biased bracket. This pin is in a preferred embodiment with a remote display in conjunction and operates them.

The invention will be explained below with reference to exemplary embodiments and with the aid of figures.

• Fig. 1 Vorder- und Rückseite der kupferkaschierten Leiterplatte mit entsprechenden Kontakt- und Anschlussflächen;
• Fig. 2 Ober- und Unterseite bzw. Vorder- und Rückseite des ebenfalls aus einem Leiterplattenmaterial bestehenden Abtrennschiebers;
• Fig. 3 eine Darstellung des mit der ersten Seite der kupferkaschierten Leiterplatte durch Löten verbundenen Varistors;
• Fig. 4 eine Ansicht der zweiten Seite der kaschierten Leiterplatte mit dort durch Lötung angeordnetem Abtrennschieber;
• Fig. 5 eine Darstellung der Positionen des Abtrennschiebers im Normalfall (linksseitig) und Abtrennfall (rechtsseitig);
• Fig. 6 eine Darstellung einer Überspannungsschutzvorrichtung gemäß einer Ausführungsform der Erfindung innerhalb eines Gehäuses eines Steckteils in teilweggebrochener Form mit erkennbarer Position des Abtrennschiebers im Betriebsfall;
• Fig. 7 eine Darstellung gemäß derjenigen nach Fig. 6, jedoch mit einer Position des Abtrennschiebers im abgetrennten Zustand;
• Fig. 8 bis 10 Darstellungen der Überspannungsschutzvorrichtung im Gehäuse eines Steckteils mit erkennbarem federvorgespannten Bügel, und zwar im ordnungsgemäßen Betriebszustand (Fig. 8); im Zustand einer thermischen Vorschädigung mit entsprechend freigelegtem Feld der Anzeigeeinrichtung (Fig. 9) und im vollständig abgetrennten Zustand, d.h. im Fehlerfall und diesbezüglich ersichtlichem Feld der Anzeigefläche (Fig. 10).

Hereby show:

• Fig. 1 Front and back of the copper-clad circuit board with corresponding contact and pad surfaces;
• Fig. 2 Top and bottom or front and back of the existing also of a printed circuit board material Abtrennschiebers;
• Fig. 3 a representation of the connected to the first side of the copper-clad circuit board by soldering varistor;
• Fig. 4 a view of the second side of the laminated circuit board with there arranged by soldering Abtrennschieber;
• Fig. 5 a representation of the positions of the separation slide in the normal case (left side) and separation case (right side);
• Fig. 6 an illustration of an overvoltage protection device according to an embodiment of the invention within a housing of a male part in teilwegbrorochener form with recognizable position of the Abtrennschiebers during operation;
• Fig. 7 a representation according to those after Fig. 6 but with a position of the separation slide in the separated state;
• Fig. 8 to 10 Representations of the overvoltage protection device in the housing of a male part with a recognizable spring-biased bracket, in the proper operating condition ( Fig. 8 ); in the state of thermal damage with corresponding exposed field of the display device ( Fig. 9 ) and in the completely separated state, ie in the event of an error and in this regard apparent field of the display area ( Fig. 10 ).

Like in the Fig. 1 As a front and back side representation apparent embodiment has the first side of the circuit board 1 (back) has a large surface area 2 for soldering the active element of the overvoltage protection device, such as a varistor (see Fig. 3 ).

Within this area 2 there is a via area. This via region 3 connects to the second side of the laminated circuit board 1 (front side).

In addition, the second side of the laminated printed circuit board 1 has a first contact surface 4 connected to the plated-through region 3. About a separation distance 5, a second contact surface 6 is formed.

The Indian Fig. 2 shown separating slide 7 bridges the contact surfaces 4 and 6 and are in the overload case, the separation distance 5, which is free of a conductive surface, free.

The second contact surface 6 is very large area and thus current-carrying connected to the area 8, for soldering, for example, an electrical connection angle 9, such as in the Fig. 6 and 7 can be seen, this connection angle 9 is connected to a plug contact 10.

Like from the Fig. 2 is traceable, there is also the Abtrennschieber 7 of a laminated printed circuit board material. The conductive area of the circuit board material of the separation slide 7 bridging the contact areas comprises a first and a second soldering section 12 with a flow throat 13 therebetween. The separation slide has a cone-side end 14 with a shape compatible with a corresponding recess 15 in the interior of the housing 16 of the plug-in part is.

The Fig. 3 shows the first side of the copper-clad circuit board 1 soldered there varistor 16, on the recognizable surface of a contact plate 17 with terminal lug 18 is also arranged by soldering.

The plan view of the second side of the laminated circuit board 1 according to Fig. 4 shows the state of Abtrennschiebers 7 in the usual case of operation. The plated-through area 3 on this side of the printed circuit board 1 is free or separated by solder mask from the contact surface 4, ie not integrated into the soldering between the separating slide 7 and the corresponding contact surface on the printed circuit board 1.

The arrow representation symbolizes the direction in which a later explained bracket ( Fig. 8 to 10 ) Brings forces to act to move the Abtrennschieber 7 in case of overload on the separation point 6 in a corresponding Abtrennzustand.

The representation after Fig. 5 shows again in comparison the state of operation case (left) and separation case (right). The thermal separation can be realized, on the one hand, by the fact that the varistor heats up so much due to overload or due to aging that a corresponding low-temperature solder melts and the movement of the separating slide releases. Also, in the case of short circuit, the constriction 13 can heat up so far that a melting occurs and the separating device is triggered.

As already from the Fig. 1 . 4 and 5 is apparent, is located on the second side of the copper-clad circuit board 1, outside the range of movement of the Abtrennschiebers 7, a Lötstützpunktfläche 20, which attaches a releasing on heating lock button or a blocking pill 21 (see Fig. 6 ) serves.

The lock button or the blocking pill 21 likewise consists of a copper-clad printed circuit board material and is connected in a material-bonded manner to the soldering support 20.

The representations after the Fig. 6 and 7 now show how the compact overvoltage protection device is integrated in a housing 16 of a corresponding overvoltage protection plug-in part.

In the partially broken representation after the Fig. 6 and 7 can be seen how by a curved portion 22 of the housing 16, the desired movement of the Abtrennschiebers 7 can be maintained when the Abtrennfall, ie the thermal overload case is present. Also, the recess 15 in the housing interior 16 can be seen, which receives the relevant club-like end of the Abtrennschiebers leading and pivotable.

In addition, a receiving space 23 is provided inside the housing 16, which offers the possibility of receiving the blocking button or blocking pill 21 when the connecting solder melts.

Decisive for the movement of the Abtrennschiebers 7 is the spring-biased bracket 30, which is subject to a pivot point 31, which is present as a fixed point in the housing 16, a pivotable mounting. A leg-like extension 32 of the bracket 30 receives a spring 33 and is supported on the inner side of the housing bottom 34 from. The spring-biased bracket 30 is also still in operative connection with a status indicator 35th

The status display 35 may show a lateral movement in the illustrations of FIGS. 8 to 10 from left to right and release different fields, which may be different in color, release. As a result, it is always recognizable via an unillustrated viewing window of the housing whether the actual overvoltage protection device located inside the housing is functional, a case of previous damage has occurred or a failure has occurred.

Furthermore, the spring-biased bracket 30 has a stop 36 which rests against the locking button or the blocking pill 21.

After thermally induced release of the lock button 21 from the Lötstützpunktfläche the spring-biased bracket 30 occurs on a non-recognizable in the figures projection on the power side with the Abtrennschieber 7 in operative connection.

As the Fig. 9 makes clear, after releasing the lock button 21, the status display 35, a first signaling surface 40 free.

After the thermally induced release and movement of the separation slide 7, a second signaling surface 41 is released and the separation state (red field) is signaled.

After the prefabricated unit made of copper-clad circuit board with soldered varistor and applied by soldering Abtrennschieber was introduced into the housing of the male part, only the mounting side of the bracket and condition indicator is to be mounted. Significant soldering processes are no longer required for the effect of thermal separation.

The blocking button or blocking pill 21 is connected to the corresponding soldering pad surface 20 with solder melting at a first temperature and the separating slide 7 is connected to a solder melting at a second temperature with the corresponding contact surfaces, the first temperature being lower than the second temperature. This ensures that a prior damage of the varistor with the result of the release of the lock button or the blocking pill is recognizable. Only with reaching this state, a frictional connection between the bracket 30 and the Abtrennschieber 7 by resorting to the force of the spring 33 causes. The spring force can be selected to be high enough to overcome existing frictional forces between the opposing surfaces of the Abtrennschiebers 7 and the copper-clad circuit board 1 and quickly and safely bring about the separation state, without this higher force is permanently on the functionally essential solder joint effect.

How easy from the Fig. 3 can be traced, requires the entire overvoltage protection device with the technical means for thermal separation in case of overload only one such area, which corresponds essentially to the largest surface area of the varistor itself as a protective element. Thus, the varistor, the copper-clad circuit board, the Abtrennschieber together with spring-biased bracket form a small-sized sandwich assembly.

Claims (15)

1. A compact, varistor-based overvoltage protection device which can be preassembled, comprising a thermal separating unit, consisting of a circuit board (1) laminated on two sides and having a through-connection region (3), wherein at least one varistor (16) is connected, in particular soldered, to a first side of the laminated circuit board (1), and furthermore a separating slide (7) operatively connected to the through-connection region (3) is provided on the second side of the laminated circuit board (1),
   wherein a first contact surface (4) contiguous with the through-connection region (3) and a second contact surface (6) spaced therefrom by a separation distance (5) are formed on the second side of the laminated circuit board (1), the separating slide (7) bridging both contact surfaces (4; 6) and releasing the separation distance (5) in the event of overload,
   characterized in that
   the separating slide (7) consists of a laminated circuit board material, wherein the conducting region of the circuit board material of the separating slide (7) bridging the contact surfaces (4; 6) has a first (11) and a second (12) soldered section having a current constriction (13) located between them.
2. The overvoltage protection device according to claim 1,
   characterized in that
   the separating slide (7) is formed as a pivot slide or rotary slide.
3. The overvoltage protection device according to anyone of the preceding claims,
   characterized in that
   the second contact surface (6) is extensively connected to a surface section (8) which serves the purpose of fastening an electrical connection element (9) in particular by soldering, wherein a barrier zone is formed between the second contact surface (6) and the surface section (8) for preventing different solders from mixing.
4. The overvoltage protection device according to anyone of the preceding claims,
   characterized in that
   the first side of the laminated circuit board (1) comprises a laminated section (2) corresponding to the varistor surface for full-surface connection as well as optimum heat transfer, wherein the through-connection region (3) is integrated into this laminated section (2).
5. The overvoltage protection device according to anyone of the preceding claims,
   characterized in that
   the base material of the circuit board and the separating slide consists of plastics, laminated paper or ceramics.
6. The overvoltage protection device according to claim 5,
   characterized in that
   the base material of the circuit board is epoxy resin.
7. The overvoltage protection device according to anyone of the preceding claims,
   characterized in that
   on the second side of the laminated circuit board (1) and outside the movement range of the separating slide (7), a soldering terminal area (20) is provided which serves the purpose of fastening a locking button or locking pill (21) detaching upon heating.
8. The overvoltage protection device according to claim 7,
   characterized in that
   the locking button or locking pill (21) consists of a copper-laminated circuit board material and is connected to the soldering terminal area (20) in a material-bonded manner.
9. The overvoltage protection device according to anyone of the preceding claims,
   characterized in that
   the overvoltage protection device is inserted in a housing (16) of a plug-in part of an overvoltage protection device and is electrically connected to terminal contacts situated there.
10. The overvoltage protection device according to claim 9,
    characterized in that
    in the housing (16), a spring-biased bracket (30) is arranged which is in operative connection with the separating slide (7), on the one hand, and with a status display (35), on the other.
11. The overvoltage protection device according to claim 8 in conjunction with claim 10,
    characterized in that
    the spring-biased bracket (30) has a stop (36) resting against the locking button or locking pill (21).
12. The overvoltage protection device according to claim 11,
    characterized in that
    after a thermally caused detachment of the locking button or locking pill (21) from the soldering terminal area (20), the spring-biased bracket (30) is connected to the separating slide (7) on the force side.
13. The overvoltage protection device according to claim 12,
    characterized in that
    with the detaching of the locking button or locking pill (21), the status display (35) exposes a first signaling surface (40) and, after a thermally caused detachment and movement of the separating slide, exposes a second signaling surface (41).
14. The overvoltage protection device according to anyone of claims 9 to 13,
    characterized in that
    in the housing interior, a recess (15) for receiving a club-like end of the separating slide in a guiding manner is formed pointing away from the contact surface of the separating slide (7).
15. The overvoltage protection device according to claim 8, or according to claim 8 in conjunction with anyone of claims 9 to 14,
    characterized in that
    the locking button or locking pill (21) is connected to the soldering terminal area (20) by means of a solder melting at a first temperature, and the separating slide (7) is connected to the contact surfaces (4; 6) by means of a solder melting at a second temperature, with the first temperature being lower than the second temperature.

Images