EP4411777A1 - Temperature-dependent switch - Google Patents

Abstract

Temperature-dependent switch (10) with a housing (24) and a temperature-dependent switching mechanism (12) arranged therein. The temperature-dependent switching mechanism (12) is designed to switch, depending on its temperature, between a closed position in which the switching mechanism (12) creates an electrically conductive connection between a first external connection (14) and a second external connection (16), and an open position in which the temperature-dependent switching mechanism (12) breaks the electrically conductive connection. The two external connections (14, 16) are led out of the housing (24) in parallel next to one another in such a way that an upper side (28) of the first external connection (14) lies with an upper side (30) of the second external connection (16) in a common connection plane (E). An electrical heating resistor component (32) is arranged inside the housing (24) and is electrically connected in parallel to the switching mechanism (12). On a connection side (42), the heating resistor component (32) has a first contact surface (44) which electrically contacts the upper side (28) of the first external connection (14) and a second contact surface (46) which electrically contacts the upper side (30) of the second external connection (16).

Description

The present invention relates to a temperature dependent switch.

Temperature-dependent switches are already known in many different forms. An example of a temperature-dependent switch is shown in the DE 197 52 581 A1 Another exemplary temperature-dependent switch is disclosed in DE 198 07 288 A1 disclosed.

Such temperature-dependent switches are used in a known manner to monitor the temperature of a device. To do this, the switch is brought into thermal contact with the device to be protected via one of its outer surfaces, for example, so that the temperature of the device to be protected influences the temperature of the switching mechanism arranged inside the switch.

The switch is connected electrically in series into the supply circuit of the device to be protected via connecting cables using its external electrical connections, so that below a response temperature of the switch, the supply current of the device to be protected flows through the switch.

A temperature-dependent switching mechanism built into the switch ensures that the switch switches in a temperature-dependent manner. This temperature-dependent switching mechanism is typically arranged between two electrodes, which in turn are each electrically connected to one of the two external connections. The temperature-dependent switching mechanism is designed in such a way that, below the response temperature of the switch or the response temperature of the switching mechanism, it is in a closed position in which the switching mechanism creates an electrically conductive connection between the two electrical external connections of the switch, and when the response temperature of the switch is exceeded, it changes to an open position in which the electrically conductive connection between the two electrical external connections of the switch is separated or interrupted.

In this way, the temperature-dependent switching mechanism ensures that in its closed position, in which it is below the response temperature of the switch, it closes the supply circuit of the device to be protected and in its open position, in which it is above the response temperature of the switch, it interrupts the supply circuit of the device to be protected. This means that with the help of such a temperature-dependent switch, it can be ensured that an electrical device is automatically de-energized by the switch and thus switched off in the event of unwanted overheating.

Such temperature-dependent switches therefore provide protection against overtemperature in electrical devices of all kinds.

The temperature-dependent switching behavior of the switch mechanism is usually due to a temperature-dependent switching element, which is designed to change its geometric shape depending on its temperature. This temperature-dependent switching element changes its geometric shape when the response temperature of the switch is reached and/or exceeded in such a way that it moves the switching mechanism from its closed position to its open position.

Typically, this temperature-dependent switching element is a bi- or tri-metal element, which is designed as a multi-layer, active, sheet-metal component made of two, three or more interconnected components with different thermal expansion coefficients. The connection of the individual layers of metals or metal alloys in such bi- or tri-metal elements is usually materially bonded or positively bonded and is achieved, for example, by rolling.

Such a bimetal or trimetal switching element has a first stable geometric configuration (low temperature configuration) at low temperatures, below the response temperature of the switch, which corresponds to the response temperature of this switching element, and a second stable geometric configuration (high temperature configuration) at high temperatures, above the response temperature of the bimetal or trimetal switching element. The temperature-dependent switching element thus switches from its low temperature configuration to its high temperature configuration depending on the temperature in the manner of a hysteresis.

In addition to the temperature-dependent switching element, an additional spring element is often used in the switching mechanisms of such temperature-dependent switches, which generates or at least helps generate the mechanical closing pressure of the switching mechanism in the closed position. The spring element is a temperature-independent spring element, which is preferably made of metal. This spring element relieves the load on the switching element, particularly in the closed position of the switching mechanism, since the latter then has to apply less or no force to generate the mechanical closing pressure in the closed position of the switching mechanism.

The switching behaviour of the rear derailleur is determined by the temperature-dependent switching element as follows, regardless of whether such an additional spring element is provided or not: If the temperature of the temperature-dependent If the temperature of the switching element rises above the response temperature of the switching element as a result of the temperature in the device to be protected, the switching element snaps from its low-temperature configuration to its high-temperature configuration and in the process moves the switching mechanism from its closed position to its open position, which interrupts the flow of current through the switch. If the temperature of the switch and thus also of the temperature-dependent switching element then drops as a result of the device to be protected cooling down to below a so-called return temperature of the switching element, the switching element changes its geometric shape again from its high-temperature configuration to its low-temperature configuration, so that the switching mechanism is brought back into its closed position so that current can then flow through the switch again.

Depending on the application, however, such a re-switching may be undesirable. For safety reasons, for example, it may be necessary for the switch to be designed in such a way that it does not automatically close again after opening due to temperature if the device to be protected subsequently cools down again. For example, the switch should only be able to be closed again after the device to be protected has not only cooled down but has also been completely disconnected from the power supply.

For such cases, a so-called self-holding function was developed. DE 197 52 581 A1 In known switches, this self-holding function is achieved by arranging a resistor made of PTC material (Positive Temperature Coefficient Thermistor) between the two electrodes of the switch, which is electrically connected in parallel to the switching mechanism.

As long as the switch is in its low temperature or closed position, no current flows through the PTC material connected as a parallel resistor. However, when the switch opens, a small self-holding current flows through the parallel resistor, which heats it up and ensures that the switch remains at a temperature above the response temperature of the bimetal switching element. The self-holding current is so low that the electrical device to be protected does not suffer any further damage, so that it can cool down. However, the self-holding resistance caused by the PTC element prevents the switch from closing itself again. cools down and switches accordingly from its high-temperature or open position back to its low-temperature or closed position, which without the parallel resistor could lead to an iterative switching on and off of the electrical device to be protected.

The PTC element thus functions as a heating resistor that heats up the switch even after the switch has been opened due to temperature, as long as the electrical device to be protected is connected to the power grid, and thus keeps the switch open. This self-holding function is also very similar to the DE 198 07 288 A1 known switch is realized.

The two publications mentioned above ( DE 197 52 581 A1 and DE 198 07 288 A1 ) known switches differ essentially in the type of functional and structural design of the switching mechanism.

In the DE 197 52 581 A1 In known switches, the spring element and the temperature-dependent switching element in the switch are electrically and mechanically connected in parallel. In this design of the switching mechanism, the spring element and the temperature-dependent switching element are usually each disk-shaped and coupled to one another in terms of movement via a movable contact part. The spring element is designed as a spring disk that is attached centrally to the movable contact part. The temperature-dependent switching element is usually designed as a bimetallic snap disk that is placed over the movable contact part with a central opening. In the closed position of the switching mechanism, the spring disk presses the movable contact part against a stationary counter-contact that is arranged on a first electrode of the switch or forms a first electrode of the switch and is electrically connected to an external connection of the switch, and is supported with its outer edge on a second electrode of the switch that is electrically connected to a second external connection of the switch. In this way, in the closed position of the switch, the electric current flows between the two electrodes via the spring disk, which at the same time also generates the contact pressure with which the movable contact part is pressed against the stationary contact part. The bimetal snap disk can be In the closed position of the switching mechanism, it must be mechanically supported without force and preferably no current flows through it, which has a positive effect on its service life.

In the DE 198 07 288 A1 In the known switch, the spring element is not electrically and mechanically connected in parallel with the temperature-dependent switching element, but in series. In this design of the switch, the spring element is typically designed as an elongated spring tongue made of metal and the temperature-dependent switching element as an elongated spring tongue made of bimetal or trimetal. One end of the spring element is attached to a first electrode that is electrically connected to the first external connection of the switch. An opposite second end of the spring element is firmly connected to the temperature-dependent switching element. The free end of the temperature-dependent switching element, which is opposite the end of the switching element that is attached to the spring element, carries a movable contact part. This movable contact part interacts with a stationary contact part that is arranged on a second electrode of the switch that is electrically connected to the second external connection. In this design of the switching mechanism, the movable contact part is pressed against the stationary contact part by both the spring element and the temperature-dependent switching element in the closed position of the switching mechanism. Due to their series connection and their attachment to one another, the spring element and the temperature-dependent switching element jointly generate the closing pressure in the closed position of the switching mechanism.

Despite the different design of the rear derailleur, the derailleurs from the above-mentioned publications ( DE 197 52 581 A1 and DE 198 07 288 A1 ) known switches, the electrodes are arranged at different heights in both cases, with the temperature-dependent switching mechanism being arranged in a space provided in the housing of the switch between the two electrodes. The PTC element provided to ensure the self-holding function is arranged in both switches inside the housing, spatially parallel to the switching mechanism, also between the two electrodes. An upper side of the PTC element is electrically connected to one electrode. An opposite lower side of the PTC element is electrically connected to the other electrode.

This type of arrangement of the PTC element requires a precise design in terms of size, since the height of the PTC element must be adapted very precisely to the distance between the two electrodes. The PTC element must also be mounted very precisely to ensure electrical contact with the two electrodes of the switch.

In both of the switch designs mentioned above, not only the electrodes but also the external connections of the switch connected to them are usually offset in height and each lead out horizontally from the switch housing. In order to make the electrical connection of the switch as simple as possible, it is desirable that the two external connections are in the same plane. To ensure this, with conventional switches it is usually necessary to bend the external connections, which are usually designed as elongated plate-shaped metal sheets, outside the switch housing in order to bring the connections into the same plane. This is cumbersome and in the worst case can also lead to damage or even breakage of the external connections.

It is therefore an object of the present invention to provide a temperature-dependent switch with which the above-mentioned disadvantages can be overcome. In particular, it is an object to provide a temperature-dependent switch with a self-holding function in which the heating resistor component provided for the self-holding function can be mounted more easily, and in particular its electrical connection should be easier.

This object is achieved according to the invention by a temperature-dependent switch according to claim 1. The temperature-dependent switch according to the invention has a housing and a temperature-dependent switching mechanism arranged therein, which is designed to switch, depending on its temperature, between a closed position in which the switching mechanism establishes an electrically conductive connection between a first external connection and a second external connection, and an open position in which the temperature-dependent switching mechanism separates the electrically conductive connection. The two external connections are led out of the housing in parallel next to one another in such a way that an upper side of the first external connection is in contact with an upper side of the second external connection is located in a common connection plane. An electrical heating resistance component is arranged inside the housing and is electrically connected in parallel to the switching mechanism. This heating resistance component has on one connection side a first contact surface that electrically contacts the top side of the first external connection and a second contact surface that electrically contacts the top side of the second external connection.

The heating resistance component, which is electrically connected in parallel to the temperature-dependent switching mechanism, enables the self-holding function explained at the beginning in the switch according to the invention, which prevents unwanted switching back of the switch until the device to be protected is actually de-energized, for example by disconnecting it from the voltage network. If the switching mechanism switches from its closed position to its open position due to an increase in temperature, the electrically conductive connection between the two external connections established via the switching mechanism is interrupted. However, due to the parallel connection of the heating resistance component, a current still flows from one external connection through the heating resistance component to the other external connection. This self-holding current ensures heating and the self-holding current ensures heating of the heating resistance component. As a result, the temperature of the switch and thus also the temperature of the switching mechanism is kept above its response temperature, so that switching back to the closed position of the switching mechanism by the heating resistance component or the heat development caused by it is avoided. Only when the device to be protected is completely switched off or de-energized in another way does the heating resistance component cool down so that the temperature of the switching mechanism can fall to a level below the response temperature, which automatically causes it to switch back to the closed position in which the electrically conductive connection between the two external connections is re-established via the switching mechanism.

Unlike the switches mentioned above, the tops of the two external connections of the switch are already located inside the housing in a common connection level. This simplifies the electrical connection of the switch. In addition, This also simplifies the assembly and electrical connection of the heating resistor component.

Unlike the switches mentioned at the beginning, the two contact surfaces of the heating resistor component are arranged on one and the same connection side. Due to the additional, already mentioned arrangement of the two top sides of the external connections in one and the same connection level, the electrical contact between the heating resistor component and the two external connections can be made on one and the same side of the heating resistor component. The heating resistor component can, for example, rest on the two external connections from above. In this case, gravity alone ensures that sufficient contact pressure is created between the heating resistor component and the two external connections for most applications.

A size adjustment of the heating resistance component to the exact distance between the electrodes of the switch, as was necessary in the prior art, can also be omitted by the type of arrangement according to the invention.

The above task is thus completely solved.

Preferably, the first contact surface and the second contact surface of the heating resistor component lie in a common contact plane which is aligned parallel to the connection plane or coincides with the connection plane.

This offers the advantage of a flat surface contact. The heating resistor component can, for example, be mounted in SMD (Surface Mounted Device) design as a surface-mounted component on the two top sides of the external connections, which lie in a common plane. This guarantees good electrical contact and at the same time enables a space-saving arrangement of the heating resistor component within the switch housing.

According to a further embodiment, the first contact surface and the second contact surface of the heating resistor component are separated from one another by a gap or a contact interruption element.

The contact interruption component can, for example, be an insulator that is arranged in the connection plane between the two contact surfaces of the heating resistor component. In principle, however, it is sufficient to provide the heating resistor component on its connection side with two contact surfaces each separated from one another by a gap, which are applied directly to the heating resistor material.

The heating resistor component can therefore be manufactured inexpensively despite the relatively simple type of assembly and electrical contacting that it offers. Accordingly, the special type of arrangement and electrical contacting of the heating resistor component does not increase the overall costs of the switch in comparison to the switches with self-holding function mentioned at the beginning and known from the state of the art.

According to a further embodiment, the heating resistor component rests with its first contact surface directly on the top of the first external connection or is firmly attached thereto by means of surface mounting. Likewise, according to this embodiment, the heating resistor component rests with its second contact surface directly on the top of the second external connection or is firmly attached thereto by means of surface mounting.

The electrical contact between the heating resistor component and the two external connections of the switch can therefore be made either by means of pure surface contact. In this case, the contact plane in which the two contact surfaces of the heating resistor component are located is in the same plane as the connection plane in which the top sides of the two external connections are located.

To improve the electrical contact and the mechanical fastening of the heating resistor component, the contact surfaces of the heating resistor component can alternatively be firmly connected to the respective external connection of the switch. For example, the contact surfaces of the heating resistor component can be soldered or welded to the top sides of the respective external connection.

According to a further embodiment, the heating resistance component is pressed with its connection side against the first and the second external connection by means of a compression spring.

One and the same compression spring thus ensures the contact pressure between the heating resistance component on the one hand and both external connections on the other. This also improves the contact between the heating resistance component and the two external connections of the switch, while the spring force of the compression spring simultaneously prevents excessive mechanical stress being exerted on the heating resistance component.

Unlike the ones from the DE 197 52 581 A1 and the DE 198 07 288 A1 In known switches, the compression spring itself does not have to act as a current-carrying component, since the current flows from one external connection immediately and directly via the heating resistor component to the other external connection in the open position of the switching mechanism. Accordingly, the compression spring does not have to be made of an electrically conductive material, but can also be made of an electrically insulating material, for example plastic. This offers further cost-saving opportunities. In addition, the fact that as few components of the switch as possible are de-energized in the open position of the switching mechanism has another safety advantage.

Preferably, the compression spring engages the heating resistor component on an upper side of the heating resistor component opposite the connection side.

In other words, the compression spring is preferably arranged on the side of the heating resistor component opposite the contact surfaces. In addition to the force of gravity, the compression spring therefore ensures a further increase in contact pressure, whereby the force of the compression spring can act directly on the top of the heating resistor component.

In principle, the upper side of the heating resistor component, to which the compression spring acts, can be covered with an insulating layer to prevent an electrical short circuit via the compression spring, unless it is itself made of an electrically insulating material.

According to a further embodiment, the heating resistance component is spatially separated from the switching mechanism by at least one wall in the interior of the housing.

On the one hand, this guarantees that the heating resistor component is electrically insulated from the switchgear. On the other hand, it guarantees that even in the event of vibrations, there can be no mechanical collisions between the switchgear and the heating resistor component. The heating resistor component is preferably arranged in a form-fitting manner in a separate chamber inside the switch housing.

Preferably, the heating resistor component comprises a PTC material.

Particularly preferably, the heating resistor component has a solid cuboid-shaped block made of PTC material, on one side of which, which is referred to here as the "connection side", two contact elements made of metal are arranged at a distance from one another, on which the two contact surfaces of the heating resistor component are located.

According to a further embodiment, the housing has an insulating material carrier which carries a first stationary electrode electrically connected to the first external connection and a second stationary electrode electrically connected to the second external connection and keeps them at a distance from each other along a height direction, wherein the temperature-dependent switching mechanism is arranged inside the housing in a recess of the Insulating material carrier is arranged between the first and the second electrode, wherein the first electrode is electrically connected to the first external connection via a line connection element arranged in the housing and aligned transversely to the two electrodes, and wherein the first and the second external connection are led through the insulating material carrier at the same height with respect to the height direction.

The cable connection element provided inside the housing, which electrically connects the first electrode inside the switch with the first external connection, makes it possible to lead the two external connections through the insulating material carrier at the same height rather than at different heights as before, and to seal them off. The sealing between the external connections and the insulating material carrier can therefore be carried out at the same height, which greatly simplifies and improves the general mechanical sealing of the inside of the switch.

In addition, the external connections do not have to be bent to bring them to the same height or level. This makes it easy to connect the switch electrically without having to rework the external connections.

The line connection element is preferably a separate component which acts as an electrical line carrier between the first electrode and the first external connection and is electrically connected to the first electrode on the one hand inside the switch and is electrically connected to the first external connection on the other hand.

Similar to the switching mechanism, the heating resistance component according to this embodiment is also preferably arranged in the insulating material carrier. The heating resistance component is particularly preferably arranged in a separate recess in the insulating material carrier, separated from the switching mechanism by at least one wall.

According to a further embodiment, the first and the second external connection are arranged parallel to one another inside and outside the insulating material carrier.

According to this design, the two external connections are preferably routed through the insulating material carrier parallel to one another at the same height. This makes the electrical connection of the switch much easier, since the two external connections run parallel to one another at the same height, like a plug.

According to a further embodiment, the insulating material carrier forms a lower part of the housing, which is closed by a cover part.

The cover part is preferably designed as an extra component that is attached to the insulating material carrier that forms the lower part of the housing, for example by stamping an upper edge of the lower part. Depending on the design, the cover part can be made of an electrically conductive material, for example metal, or an electrically insulating material, for example plastic.

In a first alternative embodiment, the cover part is made of metal, whereby the cover part forms the first electrode. According to this embodiment, the cover part has two basic functions. Firstly, as part of the switch housing, it serves to shield the interior of the housing, in which the switching mechanism and the insulating material carrier are located, from the outside world and to mechanically seal it. Secondly, it simultaneously serves as the first electrode for the temperature-dependent switching mechanism. This enables a space-saving design of the switch.

According to an alternative embodiment, the cover part is made of plastic, with the first electrode being clamped between the cover part and the line connection element. In comparison to the previously mentioned embodiment, in which the cover part is made of metal and forms an electrode of the switching mechanism, an extra component that forms the first electrode is therefore necessary here. On the other hand, the housing, which has the cover part in addition to the base part or the insulating material carrier, can be made entirely of plastic, which in particular enables the switch to be manufactured cost-effectively.

The connection plane is preferably aligned orthogonally to the height direction. The height direction is the direction along which the two electrodes of the switch are spaced apart from each other. The switching mechanism is arranged in the height direction between the first electrode and the second electrode.

It is further preferred that the first electrode is arranged on a first side of the switching mechanism and the second electrode, the first and the second external terminal are arranged on a second side of the switching mechanism which is opposite in the vertical direction.

The first electrode is preferably arranged vertically above the switchgear, while the two external connections are arranged together with the second electrode on the opposite underside of the switchgear in the vertical direction. This has the advantage that the two external connections are led out of the insulating material carrier as far down as possible, close to the underside of the switch housing.

According to a further embodiment, at least a part of the second electrode is arranged in the connection plane, wherein at least a part of the first electrode is arranged parallel to the connection plane and runs parallel to it.

On the one hand, this enables a very compact and vertically flat design of the switch. On the other hand, the second electrode can then be integrally connected to the second external connection, as it is located in the same connection plane. For example, one and the same metal sheet can be used as the second electrode and the second external connection. This keeps the number of components of the switch to a minimum and simplifies the installation of the second electrode or the second external connection.

According to a further embodiment, the temperature-dependent switching mechanism has a temperature-dependent switching element which is designed to change its geometric shape depending on its temperature in order to switch the switching mechanism between the closed position and the open position.

The temperature-dependent switching element is preferably a bimetal or trimetal component.

According to a further embodiment, the temperature-dependent switching mechanism has a spring element which is designed to establish the electrically conductive connection in the closed position of the switching mechanism by being electrically conductively connected to the first external connection and generating a mechanical contact pressure with which a movable contact part of the switching mechanism is pressed against a stationary contact part which is electrically conductively connected to the second external connection.

The provision of a spring element in addition to a temperature-dependent switching element within the switching mechanism has the advantage that the temperature-dependent switching element is electrically and mechanically relieved. In addition, the contact pressure in the closed position of the switching mechanism can be increased, which in particular improves the resistance of the switch to mechanical shock. Depending on the design of the switching mechanism, the temperature-dependent switching element and the temperature-independent spring element in the switching mechanism can, as mentioned at the beginning, be connected mechanically and electrically in series or in parallel to one another.

It is understood that the features mentioned above and those to be explained below can be used not only in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the present invention.

Fig. 1

eine schematische Schnittansicht eines ersten Ausführungsbeispiels des erfindungsgemäßen Schalters, wobei sich das temperaturabhängige Schaltwerk des Schalters in seiner Schließstellung befindet;

Fig. 2

eine schematische Schnittansicht des in Fig. 1 gezeigten Ausführungsbeispiels des erfindungsgemäßen Schalters, wobei sich das temperaturabhängige Schaltwerk des Schalters in seiner Öffnungsstellung befindet;

Fig. 3A

eine schematische perspektivische Darstellung eines Ausführungsbeispiels eines in dem erfindungsgemäßen Schalter eingesetzten Heizwiderstandbauteils;

Fig. 3B

eine Draufsicht von unten auf das in Fig. 3A gezeigte Heizwiderstandsbauteil;

Fig. 4

eine schematische Draufsicht auf das in Fig. 1 gezeigte Ausführungsbeispiel des erfindungsgemäßen Schalters;

Fig. 5

eine schematische Schnittansicht eines zweiten Ausführungsbeispiels des erfindungsgemäßen Schalters, wobei sich das temperaturabhängige Schaltwerk des Schalters in seiner Schließstellung befindet;

Fig. 6

eine schematische Schnittansicht des in Fig. 5 gezeigten Ausführungsbeispiels des erfindungsgemäßen Schalters, wobei sich das temperaturabhängige Schaltwerk des Schalters in seiner Öffnungsstellung befindet;

Fig. 7

eine schematische Schnittansicht eines dritten Ausführungsbeispiels des erfindungsgemäßen Schalters, wobei sich das temperaturabhängige Schaltwerk des Schalters in seiner Schließstellung befindet; und

Fig. 8

eine schematische Schnittansicht des in Fig. 7 gezeigten Ausführungsbeispiels des erfindungsgemäßen Schalters, wobei sich das temperaturabhängige Schaltwerk des Schalters in seiner Öffnungsstellung befindet.

Embodiments of the present invention are shown in the drawings and are explained in more detail in the following description. They show:

Fig.1

a schematic sectional view of a first embodiment of the switch according to the invention, wherein the temperature-dependent switching mechanism of the switch is in its closed position;

Fig. 2

a schematic sectional view of the Fig.1 shown embodiment of the switch according to the invention, wherein the temperature-dependent switching mechanism of the switch is in its open position;

Fig. 3A

a schematic perspective representation of an embodiment of a heating resistor component used in the switch according to the invention;

Fig. 3B

a view from below of the Fig. 3A heating resistor component shown;

Fig.4

a schematic plan view of the Fig.1 shown embodiment of the switch according to the invention;

Fig.5

a schematic sectional view of a second embodiment of the switch according to the invention, wherein the temperature-dependent switching mechanism of the switch is in its closed position;

Fig.6

a schematic sectional view of the Fig.5 shown embodiment of the switch according to the invention, wherein the temperature-dependent switching mechanism of the switch is in its open position;

Fig.7

a schematic sectional view of a third embodiment of the switch according to the invention, wherein the temperature-dependent switching mechanism of the switch is in its closed position; and

Fig.8

a schematic sectional view of the Fig.7 shown embodiment of the switch according to the invention, wherein the temperature-dependent switching mechanism of the switch is in its open position.

Fig.1 and 2 each show a schematic sectional view of a first embodiment of the temperature-dependent switch according to the invention. The switch is designated in its entirety by the reference number 10.

Fig.1 shows the closed position of switch 10. Fig.2 shows the open position of switch 10.

The switch 10 has a temperature-dependent switching mechanism 12 which is designed to switch the switch 10 from its closed position to its open position and vice versa depending on its temperature.

In the Fig.1 In the closed position of the switch shown, the switching mechanism 12 establishes an electrically conductive connection between the two external terminals 14, 16 of the switch 10. In the Fig.2 In the open position of the switch 10 shown, however, the switching mechanism 12 separates the electrically conductive connection between the first external connection 14 and the second external connection 16.

The first external connection 14 is electrically connected to a first electrode 18. This first electrode 18 forms the Fig.1 and 2 shown first embodiment simultaneously the cover of the switch 10. In other words, the first electrode 18 is formed by a cover part 19 made of metal.

The second external connection 16 is electrically connected to a second electrode 20. In the embodiment shown here, the second electrode 20 is integrally connected to the second external connection 16. In other words, one and the same metal sheet forms the second electrode 20 and the second external connection 16.

Both electrodes 18, 20 are designed as flat planar electrodes. The switching mechanism 12 is arranged inside the switch 10 in the space between the two electrodes 18, 20.

The two electrodes 18, 20 are kept at a distance from one another by an insulating material carrier 22, which forms part of the housing 24 of the switch 10. The insulating material carrier 22 carries the two electrodes 18, 20 and fixes them in their arrangement. The two electrodes 18, 20 are therefore immobile, stationary electrodes.

The two electrodes 18, 20 are kept at a distance from each other by the insulating material carrier 22 along a height direction. This height direction, which in Fig.1 and 2 indicated by an arrow h, runs transversely, preferably orthogonally to the two electrodes 18, 20.

The first electrode 18 is arranged on an upper side (referred to herein as "first side") of the switching mechanism 12, while the second electrode 20 is arranged on the opposite lower side in the height direction h (referred to herein as "second side") of the switching mechanism 12.

The insulating material carrier 22 is essentially pot-shaped. It forms the lower part 23 of the housing 24. The insulating material carrier 22 is formed around the second electrode 20 by overmolding or casting such that the second electrode 20 is an integral part of the housing lower part 23.

The lower part 23 of the housing is closed by the first electrode 18 designed as a cover part 19. The cover part 19 is surrounded all around, along its entire circumference, by the insulating material carrier 22 and is held captive by a hot-stamped upper edge of the insulating material carrier 22 or the lower part 23.

A line connection element 26 made of electrically conductive material is also integrated into the insulating material carrier 22. This line connection element 26 can be, for example, a line sheet or another electrical conductor that is integrated into the insulating material carrier 22 and is therefore electrically insulated from the switching mechanism 12, which is also arranged inside the housing 24, despite its arrangement inside the housing 24. In the exemplary embodiment shown here, the line connection element 26 is L-shaped in cross section.

The line connection element 26 connects the first electrode 18 to the first external connection 14. In this way, it is possible to lead the two external connections 14, 16 through the insulating material carrier 22 from the inside to the outside at the same height despite the offset arrangement of the two electrodes 18, 20 in the height direction h. The first external connection 14 is accordingly in the Fig.1 and 2 shown sectional views "behind" the second external connection 16, since the first external connection 14 is arranged at the same height as the second external connection 16 and runs parallel to the second external connection 16. The latter is particularly evident when viewed in conjunction with the Fig.4 shown top view.

The two external connections 14, 16 run as in Fig.4 shown, outside the insulating material carrier 22 parallel to each other and can, due to the line connection element 16, in a common connection plane E, which in Fig.1 and 2 indicated by a dashed line. More precisely, in particular the two upper sides 28, 30 of the two external connections 14, 16 lie in the common connection plane E. The two external connections 14, 16 are preferably designed as flat or plate-shaped connections.

While the top of the second electrode 20 in the Fig.1 and 2 shown first embodiment is also arranged in the connection plane E, the first electrode 18 is arranged offset in the height direction h parallel to the connection plane E. The connection plane E is preferably aligned orthogonal to the height direction h.

An electrical heating resistance component 32 rests on the two external connections 14, 16 from above. This heating resistance component 32 is electrically connected in parallel to the switching mechanism 12 and is also arranged inside the housing 24 in a separately provided recess 34 of the insulating material carrier 22 to the side of the switching mechanism 12, but spatially separated from it.

The heating resistance component 32 essentially serves the function of self-holding, with which the switch 10 remains in the closed position after being opened by the switching mechanism 12. is kept open until the device to be protected by switch 10 is de-energized independently of switch 10.

The heating resistance component 32 has an approximately cuboid-shaped component 36 made of PTC material. Two contact elements 38, 40 made of conductive material are arranged on this PTC block 36. These two contact elements 38, 40 are each designed, for example, as a metal sheet that is attached to the PTC block 36. The two contact elements 38, 40 are arranged on the same side 42 of the PTC block 36. This side 42 is referred to here as the "connection side" of the heating resistance component 32.

On the connection side 42, each of the two contact elements 38, 40 has a contact surface 44, 46. Both contact surfaces 44, 46 lie in one and the same contact plane K, which coincides with the connection plane E when the heating resistor component 32 is installed. The first contact surface 44 arranged on the first contact element 38 serves to electrically contact the heating resistor component 32 to the first external connection 14. The second contact surface 46 arranged on the second contact element 40 serves to electrically contact the heating resistor component 32 to the second external connection 16.

The heating resistance component 32 thus rests flat from above on the two external connections 14, 16 of the switch 10, with the first contact surface 44 resting on the upper side 28 of the first external connection 14 and the second contact surface 46 resting on the upper side 30 of the second external connection 16.

To increase the contact pressure between the two contact surfaces 44, 46 and the top sides 28, 30, the heating resistor component 32 is pressed with its connection side 42 against the two external connections 14, 16 with the aid of a compression spring 48. This compression spring 48 engages the heating resistor component 32 on a top side 50 opposite the connection side 42. The heating resistor component 32 can be covered on the top side 50 by an insulating layer 52 in order to electrically insulate the PTC block 36 from the compression spring 48.

To isolate the two contact elements 38, 40 from each other, a contact interruption element 54 can be arranged between them (see Fig. 3A and 3B ). Alternatively, the two contact elements 38, 40 of the heating resistor component 32 are separated from each other by a gap (air gap).

The basic arrangement of the two external connections 14, 16 and the heating resistance component 32 is also Fig.4 visible. Fig.4 shows a top view of the switch 10, with some components arranged inside the housing 24 (for example components 20 and 26) indicated by dashed lines. The second electrode 20, which in Fig.4 indicated by dashed lines, runs obliquely or at an angle to the second external connection 16, but, as already mentioned, lies together with the second external connection 16 in the connection plane E. The second electrode 20 does not necessarily have to run at an angle or at an angle to the second external connection 16, as is shown in Fig.4 is shown. The second electrode 20 can basically also be aligned with the first external connection 16. In such a case, it is preferred that the second external connection 16 runs together with the second electrode 20 in the radial direction of the switch housing 24. If the second external connection 16 is in the middle, i.e. opposite the Fig.4 shown position is arranged parallel downwards in the direction of the first external connection 14, a parallel alignment of the two external connections 14, 16 is also possible. With regard to Fig.4 the second external terminal 16 and the second electrode 20 would then be arranged in a line parallel to the first external terminal 14 in the center of the housing.

Even in the Fig. 5-8 In the embodiments of the switch 10 according to the invention shown, the two upper sides 28, 30 of the external connections 14, 16 are arranged in a common connection plane and a heating resistor component 32 is provided for implementing the self-holding function of the switch 10, wherein the heating resistor component 32 with its two contact surfaces 44, 46, which are also located in a common contact plane K, rests from above on the upper sides 28, 30 of the two external connections 14, 16. This basic arrangement and contacting principle of the heating resistor component 32 as well as the Fig. 3A and 3B The outlined structure of the heating resistor component 32 is therefore also applicable to the Fig. 5-8 The two embodiments shown in Fig. 5-8 The examples shown differ from the Fig. 1-2 shown first embodiment in the functional and structural nature of the design of the switching mechanism 12 as well as in some features of the housing 24 to be explained below.

In the Fig.1 and 2 In the first embodiment shown, the switching mechanism 12 has a temperature-dependent switching element 56 which is electrically and mechanically connected in series with a spring element 58. In the first embodiment, the temperature-dependent switching element 56 is designed as a bimetal element which has the shape of an elongated spring tongue. The spring element 58 is made of metal and is also designed as an elongated spring tongue.

A first end 60 of the spring element 58 is firmly attached to the first electrode 18. Starting from this first end 60, the spring element 58 projects like a cantilever beam into the cavity formed by the recess 61 inside the switch 10. The opposite second, free end 62 of the spring element 58 is firmly attached (e.g. by soldering or welding) to a first end 64 of the temperature-dependent switching element 56. At a second end 66 opposite the first end 64, the temperature-dependent switching element 56 carries a movable contact part 68 which interacts with a stationary contact part 70 arranged on the second electrode 20.

In the closed position, the movable contact part 68 is pressed against the stationary contact part 70 by the spring element 58 and the temperature-dependent switching element 56, whereby the switch 10 is closed and the electrically conductive connection between the two external terminals 14, 16 is established.

If, based on this, the temperature of the switching element 56 increases as a result of an increased current flow through the switch 10 or as a result of an increased outside temperature, the creeping phase of the switching element 56 begins, in which its spring force, which works against the force of the spring element 58, decreases. Due to the mechanical series connection of the switching element 56 with the spring element 58, this gradual decrease in the force of the switching element 56 is compensated for by the spring element 58. balanced so that the movable contact part 68 is still pressed against the stationary contact part 70.

If the temperature of the switching element 56 then increases further to or above the response temperature of the switching element 56, the switching element 56 snaps into its Fig. 2 shown high-temperature configuration, whereby the switching mechanism 12 is brought into its open position and the electrically conductive connection between the two external terminals 14, 16 is interrupted.

In the Fig.2 In the open position of the switch 10 shown, no more current flows from the first external connection 14 via the switching mechanism 12 to the second external connection 16. However, a small residual current still flows between the two external connections 14, 16 via the heating resistor component 32. This residual current causes the heating resistor component 32 to heat up automatically. The heat development caused by this is also transferred to the switching mechanism 12 and the associated temperature-dependent switching element 56. Accordingly, the heating resistor component 32 causes the so-called self-holding of the switch 10, by which the switch 10 is kept permanently open until there is no longer any voltage from the outside between the two external connections 14, 16. This is usually only the case when the device to be monitored by the switch 10 is switched off, for example by disconnecting it from the power grid.

Without the heating resistor component 32, which is electrically connected in parallel to the switching mechanism 12, the switching mechanism 12 would automatically return to its Fig.1 shown closed position as soon as the temperature of the device to be monitored by switch 10 and thus also the temperature of switch 10 drops again.

In the Fig.5 and 6 In the second embodiment shown, the temperature-dependent switching behavior of the switch 10 is effected by a structurally and functionally differently constructed switching mechanism 12. However, the previously explained principle of self-holding, which is effected by the heating resistor component 32, is also retained here. The above-mentioned type of arrangement of the heating resistor component 32 with its one-sided contact with the two external terminals 14, 16 is in the Fig.5 and 6 shown embodiment of the temperature-dependent switch according to the invention.

The rear derailleur 12 comprises Fig.5 and 6 The switch 10 shown has a temperature-dependent switching element 56 and a temperature-dependent spring element 58. The switching element 56 is designed here as a disc-shaped bimetal element, which is why it is also referred to as a bimetal disc. The spring element 58 is also disc-shaped and preferably designed as a spring snap disc, which has two temperature-independent stable configurations, between which it snaps back and forth under the influence of force.

The switching element 56 and the spring element 58 are in the Fig.5 and 6 shown second embodiment are electrically and mechanically connected in parallel to one another. The movable contact part 68 is firmly attached to the spring element 58. The switching element 56, which is designed as a bimetallic disk, is placed over the movable contact part 68 with a hole 72 provided in the middle.

The cover part 19, which is preferably made of metal as in the first embodiment, functions as the first electrode 18. The first electrode 18 is, as before, electrically connected to the first external connection 14 via the line connection element 26, which is embedded in the insulating material carrier 22.

The second electrode 20 is a metal sheet embedded in the insulating material carrier 22, which at least partially lies with the external connections 14, 16 in the connection plane E, in which the contact surfaces 44, 46 of the heating resistor component 32 are also arranged.

Unlike in the first embodiment, the stationary contact part 70 is not designed as a separate component that is integrally connected to the second electrode 20, but is formed by a raised central portion of the second electrode 20 itself.

In the Fig.5 In the closed position of the switch 10 shown, the disk-shaped spring element 58 is supported with its outer edge 74 on the inside of the cover part 19 and thus on the first electrode 18. The temperature-dependent switching element 56 can be mounted without force in this closed position of the switch 10 and can protrude freely with its outer edge 76 into the recess 61 formed in the interior of the switch 10. The switching element 56 is thus, unlike in the first embodiment, not subject to current in the closed position of the switch 10.

In the closed position of the switch 10, the current flows from the first external connection 14 via the line connection element 26 into the first electrode 18 and from there via the spring element 58, the movable contact part 68, the stationary contact part 70 and the second electrode 20 to the second external connection 16.

Likewise, the temperature-dependent switching element 56 in the Fig.5 shown closed position of the switch does not contribute to the contact pressure with which the movable contact part 68 is pressed against the stationary contact part 70. This closing pressure is Fig.5 and 6 shown structure of the rear derailleur 12 is only effected by the spring element 58.

If the temperature of the switch 10 and thus also of the switching mechanism 12 increases to the response temperature of the switching element 56 or above this, the switching element 56 snaps from its Fig.5 shown convex position in its Fig.6 shown concave position. The switching element 56 rests with its outer edge 76 on the insulating material carrier 22 and presses the spring element 58 out of its Fig.5 shown concave position in its in Fig.6 shown convex position, whereby the movable contact part 68 is lifted from the stationary contact part 70 and the electrically conductive connection established by the switching mechanism 12 is opened.

In the Fig.6 In the open position of the switching mechanism 12 shown, the current flows between the first external terminal 14 and the second external terminal 16 only through the heating resistance component 32, which heats up as previously mentioned and holds the switch 10 in the open position until the power supply is completely interrupted.

In the Fig.7 and 8th In the third embodiment of the switch 10 according to the invention shown, the switching mechanism 12 is functionally similar to the switching mechanism 12 according to the Fig.5 and 6 shown second embodiment of the switch 10 according to the invention. The switching element 56 and the spring element 58 are mechanically and electrically connected in parallel. In addition, the switching element 56 and the spring element 58 are also in the Fig.7 and 8th shown third embodiment are disk-shaped or circular disk-shaped and connected with their respective center to the movable contact part 68.

In this case, however, the switching element 56 and the spring element 58 rest from opposite sides on a circumferential collar 74 forming the outer edge of the movable contact part 68.

In addition to the switching element 56, the spring element 58 and the movable contact part 68, the switching mechanism 12 has, according to the Fig.7 and 8th The third embodiment of the switch 10 shown has a switching mechanism housing 80. This switching mechanism housing 80 is preferably made of metal. It serves to accommodate the switching mechanism 12 or the switching mechanism unit formed from the switching element 56, spring element 58, and movable contact part 68.

The derailleur housing 80 is designed as a partially open housing and is preferably made of metal. The derailleur unit formed from the switching element 56, spring element 58 and movable contact part 68 is held captive, but with play, in the derailleur housing 80.

With the aid of such a switchgear housing 76, it is possible to pre-produce the switchgear 12 as a semi-finished product, to keep it in stock as bulk goods and then to insert it as a whole into the switch housing 24.

In the Fig.7 In the closed position of the switch shown, the spring element 58 rests with its outer edge 74 on the inside of the switch housing 80 and presses the movable contact part 68 against the stationary contact part 70. The In this embodiment of the switching mechanism 12, the switching element 56 is also mounted mechanically force-free in the closed position of the switch 10 and no current flows through it.

In the Fig.7 and 8th In the switch 10 shown, the switching mechanism housing 80 functions as the first electrode 18 of the switching mechanism 12. Accordingly, the cover part 19 does not have to be made of electrically conductive material, but can be made of plastic, e.g. of a similar or even the same material as the insulating material carrier 22, which forms the lower part 23 of the housing 24.

If the cover part 19 is made of plastic, the heating resistance component 32 does not have to be electrically insulated from the compression spring 48, which is why the insulation layer 52 can be omitted. Here too, the heating resistance component 32 lies directly on the top sides 28, 30 of the external connections 14, 16 with its contact surfaces 44, 46 provided on the bottom or connection side 42.

The switchgear housing 80 acting as the first electrode 18 rests on the line connecting element 26, so that here too the line connecting element 26 provided inside the switch establishes the electrical contact between the first electrode 18 and the first external connection 14 and enables the two external connections 14, 16 to be attached at the same height or the external connections 14, 16 to be led out of the insulating material carrier 22 at the same height.

The current flow in the Fig.7 The closed position of the switch shown takes place from the first external terminal 14 via the line connection element 26, the switchgear housing 80 (the first electrode 18), the spring element 58, the movable contact part 68, the stationary contact part 70 and the second electrode 20 to the second external terminal 16.

In the Fig.8 In the open position of the switch 10 shown, the temperature-dependent switching element 56 rests with its outer edge 76 on the inside of the switch housing 80 and presses the movable contact part 68 upwards, whereby the movable contact part 68 is lifted off the stationary contact part 70 and the Current flow through the switching mechanism 12 is interrupted. This also causes the spring element 58 to snap from its Fig.7 shown concave position in its in Fig.8 shown convex position.

Here too, the opening position is kept open by the self-holding effect of the heating resistor component 32 until there is no longer any voltage between the two external connections 14, 16.

Accordingly, the three exemplary embodiments shown here differ essentially in the structure of the switching mechanism 12, while the principle of the self-holding effected by the heating resistance component 32 as well as the type of arrangement and electrical contacting of the heating resistance component 32 and the attachment of the two external connections 14, 16 in a common connection level E by providing a line connection element 26 arranged in the interior of the switch are implemented in a fundamentally similar manner in all three exemplary embodiments.

Claims (15)

Temperature-dependent switch (10), with a housing (24) and a temperature-dependent switching mechanism (12) arranged therein, which is designed to switch, depending on its temperature, between a closed position in which the switching mechanism (12) establishes an electrically conductive connection between a first external connection (14) and a second external connection (16), and an open position in which the temperature-dependent switching mechanism (12) separates the electrically conductive connection, wherein the two external connections (14, 16) are led out of the housing (24) in parallel next to one another in such a way that an upper side (28) of the first external connection (14) lies with an upper side (30) of the second external connection (16) in a common connection plane (E), and wherein an electrical heating resistor component (32) is arranged in the interior of the housing (24), which is electrically connected in parallel to the switching mechanism (12) and on a connection side (42) a first contact surface (44) which contacts the upper side (28) of the first external terminal (14) and a second contact surface (46) which electrically contacts the upper side (30) of the second external terminal (16). Temperature-dependent switch according to claim 1, wherein the first contact surface (44) and the second contact surface (46) lie in a common contact plane (K) which is aligned parallel to the connection plane (E) or coincides with the connection plane (E). Temperature-dependent switch according to claim 1 or 2, wherein the first contact surface (44) and the second contact surface (46) are separated from each other by a gap or a contact interruption element (54). Temperature-dependent switch according to one of claims 1-3, wherein the heating resistance component (32) with its first contact surface (44) lies directly on the upper side (28) of the first external connection (14) or is firmly attached thereto by means of surface mounting, and wherein the heating resistance component (32) with its second contact surface (46) directly on the upper side (30) of the second external connection (16) or is firmly attached thereto by means of surface mounting. Temperature-dependent switch according to one of claims 1-4, wherein the heating resistance component (32) is pressed with its connection side (42) against the first and the second external connection (14, 16) by means of a compression spring (48). Temperature-dependent switch according to claim 5, wherein the compression spring (48) acts on the heating resistor component (32) on an upper side (50) of the heating resistor component (32) opposite the connection side (42). Temperature-dependent switch according to one of claims 1-6, wherein the heating resistance component (32) is spatially separated from the switching mechanism (12) by at least one wall (65) in the interior of the housing (24). Temperature dependent switch according to one of claims 1-7, wherein the heating resistance component (32) comprises a PTC material. Temperature-dependent switch according to one of claims 1-8, wherein the housing (24) has an insulating material carrier (22) which carries a first stationary electrode (18) electrically connected to the first external connection (14) and a second stationary electrode (20) electrically connected to the second external connection (16) and keeps them at a distance from one another along a height direction (h), wherein the temperature-dependent switching mechanism (12) is arranged inside the housing (24) in a recess (61) of the insulating material carrier (22) between the first and the second electrode (18, 20), wherein the first electrode (18) is electrically connected to the first external connection (14) via a line connection element (26) arranged in the housing (24) and aligned transversely to the two electrodes (18, 20), and wherein the first and the second external connection (14, 16) are connected at the same height with respect to the height direction (h) by the insulating material carrier (22) are passed through. Temperature-dependent switch according to claim 9, wherein the first and the second external terminal (14, 16) are arranged parallel to one another inside and outside the insulating material carrier (22). Temperature-dependent switch according to claim 9 or 10, wherein the insulating material carrier (22) forms a lower part (23) of the housing (24) which is closed by a cover part (19). Cover part (19) made of plastic or metal. Temperature-dependent switch according to one of claims 9-11, wherein the connection plane (E) is aligned orthogonal to the height direction (h). Temperature-dependent switch according to one of claims 9-12, wherein the first electrode (18) is arranged on a first side of the switching mechanism (12), and wherein the second electrode (20), the first and the second external terminal (14, 16) are arranged on a second side of the switching mechanism (12) opposite in the height direction (h). Temperature-dependent switch according to one of claims 1-13, wherein the temperature-dependent switching mechanism (12) has a temperature-dependent switching element (56) which is designed to change its geometric shape depending on its temperature in order to switch the switching mechanism (12) between the closed position and the open position. Temperature-dependent switch according to one of claims 1-14, wherein the temperature-dependent switching mechanism (12) has a spring element (58) which is designed to establish the electrically conductive connection in the closed position of the switching mechanism (12) by being electrically conductively connected to the first external connection (14) and generating a mechanical contact pressure with which a movable contact part (68) of the switching mechanism (12) is pressed against a stationary contact part (70) which is electrically conductively connected to the second external connection (16).

Images