Temperature-dependent switch

Abstract

A temperature-dependent switch (10) comprises a housing (24) and a temperature-dependent switching mechanism (12) arranged therein. The temperature-dependent switching mechanism (12) is configured 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 terminal (14) and a second external terminal (16), and an open position, in which the temperature-dependent switching mechanism (12) breaks the electrically conductive connection. The two external terminals (14, 16) extend parallel to each other from the housing (24) such that a top surface (28) of the first external terminal (14) lies in a common terminal plane (E) with a top surface (30) of the second external terminal (16). An electrical heating element (32) is arranged inside the housing (24) and is electrically connected in parallel to the switching mechanism (12).On one connection side (42) the heating resistance component (32) has a first contact surface (44) which electrically contacts the top (28) of the first external connection (14) and a second contact surface (46) which electrically contacts the top (30) of the second external connection (16).

Description

[0001] The present invention relates to a temperature-dependent switch.

[0002] Temperature-dependent switches are already known in principle in numerous forms. A temperature-dependent switch, which forms the basis for the preamble of claim 1, is disclosed in EP 0 951 041 A2. Further exemplary temperature-dependent switches are disclosed in DE 197 52 581 A1, DE 198 07 288 A1, and DE 197 27 197 A1.

[0003] Such temperature-dependent switches are used in a conventional manner to monitor the temperature of a device. For this purpose, the switch is brought into thermal contact with the device to be protected, for example, via one of its outer surfaces, so that the temperature of the device to be protected influences the temperature of the switching mechanism located inside the switch.

[0004] 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.

[0005] A temperature-dependent switching mechanism built into the switch ensures temperature-dependent switching behavior of the switch. This temperature-dependent switching mechanism is typically arranged between two electrodes, which in turn are each electrically connected to one of the two external terminals. The temperature-dependent switching mechanism is designed such 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 establishes an electrically conductive connection between the two electrical external terminals of the switch. 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 terminals of the switch is separated or interrupted.

[0006] In this way, the temperature-dependent switch ensures that, in its closed position, where it is below the switch's response temperature, it closes the supply circuit of the device to be protected, and in its open position, where it is above the switch's response temperature, it interrupts the supply circuit of the device to be protected. Thus, using such a temperature-dependent switch, it can be ensured that an electrical device is automatically de-energized and thus switched off by the switch in the event of undesirable overheating.

[0007] Such temperature-dependent switches therefore provide protection against overtemperature in all types of electrical devices.

[0008] The temperature-dependent switching behavior of the switch's switching mechanism is usually due in particular to a temperature-dependent switching element, which is designed to change its geometric shape depending on its temperature. When the switch's response temperature is reached and / or exceeded, this temperature-dependent switching element changes its geometric shape in such a way that it moves the switching mechanism from its closed position to its open position.

[0009] Typically, this temperature-dependent switching element is a bi- or tri-metallic element, which is designed as a multi-layer, active, sheet-metal component consisting of two, three, or more interconnected components with different thermal expansion coefficients. The connection between the individual layers of metals or metal alloys in such bi- or tri-metallic elements is usually materially bonded or positively bonded and is achieved, for example, by rolling.

[0010] Such a bimetallic or trimetallic switching element exhibits 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 bimetallic or trimetallic switching element. The temperature-dependent switching element thus switches from its low-temperature configuration to its high-temperature configuration depending on the temperature, in a hysteresis manner.

[0011] 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 contributes to the mechanical closing pressure of the switching mechanism in the closed position. The spring element is a temperature-independent spring element, 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 switching element then has to exert less or no force to generate the mechanical closing pressure.

[0012] The switching behavior of the switching mechanism is largely determined by the temperature-dependent switching element, regardless of whether such an additional spring element is provided or not, as follows: If the temperature of the temperature-dependent switching element rises above the response temperature of the switching element as a result of a temperature increase in the device to be protected, the element snaps from its low-temperature configuration to its high-temperature configuration, thereby moving the switching mechanism from its closed position to its open position, interrupting the current flow through the switch. If the temperature of the switch and thus also of the temperature-dependent switching element subsequently drops below a so-calledIf the return temperature of the switching element drops, the switching element changes its geometric shape from its high-temperature configuration to its low-temperature configuration, so that the switching mechanism is brought back into its closed position and current can then flow through the switch again.

[0013] Depending on the application, however, such a reversing action may be undesirable. For safety reasons, for example, it may be necessary for the switch to be designed so that it does not automatically reclose after a temperature-related opening if the protected device subsequently cools down. For example, the switch should only be able to be reclosed after the protected device has not only cooled down but has also been completely disconnected from the power supply.

[0014] For such cases, a so-called self-holding function was developed. In the switch known from DE 197 52 581 A1, this self-holding function is achieved by placing a resistor made of PTC material (Positive Temperature Coefficient Thermistor) between the two electrodes of the switch, which is electrically connected in parallel with the switching mechanism.

[0015] 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, heating it up and ensuring that the switch remains at a temperature above the response temperature of the bimetallic switching element. The self-holding current is so low that the electrical device to be protected suffers no further damage, allowing it to cool down. However, the self-holding resistance caused by the PTC element prevents the switch from cooling down again and switching from its high-temperature or open position back to its low-temperature or closed position. Without the parallel resistor, this could lead to the electrical device to be protected being switched on and off repeatedly.

[0016] The PTC element thus acts as a heating resistor, heating the switch even after a temperature-related opening of the switch, as long as the electrical device to be protected is connected to the power supply, thus keeping the switch open. This self-holding function is also implemented in a very similar way in the switch known from DE 198 07 288 A1.

[0017] The two switches known from the documents mentioned at the beginning (DE 197 52 581 A1 and DE 198 07 288 A1) differ essentially in the type of functional and structural design of the switching mechanism.

[0018] In the switch known from DE 197 52 581 A1, the spring element and the temperature-dependent switching element are electrically and mechanically connected in parallel. In this switching mechanism design, the spring element and the temperature-dependent switching element are usually disc-shaped and coupled to each other via a movable contact part. The spring element is designed as a spring washer, which is centrally attached to the movable contact part. The temperature-dependent switching element is usually designed as a bimetallic snap-action disc, which is placed over the movable contact part with a central opening.In the closed position of the switching mechanism, the spring washer presses the movable contact part against a stationary counter-contact which is arranged on a first electrode of the switch or forms a first electrode of the switch and is electrically connected to an external terminal of the switch, and is supported with its outer edge on a second electrode of the switch, which is electrically connected to a second external terminal of the switch. In this way, in the closed position of the switch, the electrical current flows between the two electrodes via the spring washer, which simultaneously generates the contact pressure with which the movable contact part is pressed against the stationary contact part. In the closed position of the switching mechanism, the bimetallic snap-action disc can be mounted mechanically force-free and is preferably not subject to current, which has a positive effect on its service life.

[0019] In the switch known from DE 198 07 288 A1, the spring element is not electrically and mechanically connected in parallel with the temperature-dependent switching element, but in series. In this switch design, 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 electrically connected to the first external terminal of the switch. An opposite second end of the spring element is fixedly 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 attached to the spring element, carries a movable contact part.This movable contact part interacts with a stationary contact part located on a second electrode of the switch that is electrically connected to the second external terminal. With 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.

[0020] Despite the different design of the switching mechanism, in both switches known from the above-mentioned publications (DE 197 52 581 A1 and DE 198 07 288 A1), the electrodes are arranged at a height offset from one another, with the temperature-dependent switching mechanism being located in a space provided in the switch housing between the two electrodes. The PTC element, which ensures 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.

[0021] This type of PTC element arrangement requires a precise design, as the height of the PTC element must be precisely adjusted to the distance between the two electrodes. The PTC element must also be mounted with great precision to ensure electrical contact with the two electrodes of the switch.

[0022] In both of the aforementioned switch designs, not only the electrodes but also the external terminals of the switch connected to them are usually offset in height and each lead out horizontally from the switch housing. To simplify the electrical connection of the switch as much as possible, it is desirable for the two external terminals to be in a common plane. To ensure this, with conventional switches it is usually necessary to bend the external terminals, which are usually designed as elongated, plate-shaped metal sheets, outside the switch housing in order to bring the terminals into a common plane. This is cumbersome and, in the worst case, can lead to damage or even breakage of the external terminals.

[0023] It is therefore an object of the present invention to provide a temperature-dependent switch that can overcome the aforementioned disadvantages. 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.

[0024] 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 terminal and a second external terminal, and an open position in which the temperature-dependent switching mechanism breaks the electrically conductive connection. The two external terminals are led out of the housing in parallel next to one another in such a way that an upper side of the first external terminal lies in a common connection plane with an upper side of the second external terminal. An electrical heating resistor component is arranged inside the housing and is electrically connected in parallel to the switching mechanism.This heating resistor 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 housing has an insulating material carrier that supports 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 spaced apart from one another along a vertical direction. The temperature-dependent switching mechanism is arranged inside the housing in a recess in the insulating material carrier between the first and second electrodes.The first electrode is electrically connected to the first external terminal via a line connecting element arranged in the housing and aligned transversely to the two electrodes, and the first and second external terminals are passed through the insulating material carrier at the same height with respect to the height direction.

[0025] The heating resistor component, which is electrically connected in parallel to the temperature-dependent switching mechanism, enables the self-holding function explained above in the switch according to the invention, which prevents unwanted re-switching of the switch until the device to be protected is actually de-energized, for example by disconnecting it from the mains. If the switching mechanism switches from its closed position to its open position due to an increase in temperature, the electrically conductive connection established via the switching mechanism between the two external terminals is interrupted. However, due to the parallel connection of the heating resistor component, a current still flows from one external terminal through the heating resistor component to the other external terminal. This self-holding current ensures heating, and the self-holding current ensures heating of the heating resistor component.As a result, the temperature of the switch and thus also the temperature of the switching mechanism is kept above its response temperature, preventing the switching mechanism from switching back to the closed position due to the heating resistor component or the heat generated by it. Only when the device to be protected is completely switched off or de-energized in some other way does the heating resistor component cool down, allowing the temperature of the switching mechanism to drop below the response temperature. This automatically causes it to switch back to the closed position, in which the electrically conductive connection between the two external terminals is re-established via the switching mechanism.

[0026] Unlike the switches mentioned above, the top surfaces of the two external terminals of the switch are located inside the housing on a common connection level. This simplifies the electrical connection of the switch. It also simplifies the installation and electrical connection of the heating resistor component.

[0027] Unlike the switches mentioned above, the two contact surfaces of the heating resistor component are arranged on the same connection side. Due to the additional, previously mentioned arrangement of the two top sides of the external terminals on the same connection level, the electrical contact between the heating resistor component and the two external terminals can be made on the same side of the heating resistor component. For example, the heating resistor component can rest on the two external terminals from above. In this case, gravity alone ensures that sufficient contact pressure is established between the heating resistor component and the two external terminals for most applications.

[0028] The arrangement according to the invention also eliminates the need to adjust the size of the heating resistor component to the exact distance between the electrodes of the switch, as was necessary in the prior art.

[0029] The cable connection element provided inside the housing, which electrically connects the first electrode inside the switch to the first external terminal, allows the two external terminals to be routed through the insulating material carrier at the same height, rather than at different heights as before. The seal between the external terminals and the insulating material carrier can thus be created at the same height, which significantly simplifies and improves the general mechanical sealing of the switch interior.

[0030] Furthermore, the external terminals do not need to be bent to bring them to the same height or level. This advantageously allows for the switch's electrical connection in a simple manner without reworking the external terminals.

[0031] The line connection element is preferably a separate component which acts as an electrical line carrier between the first electrode and the first external terminal and is electrically connected to the first electrode inside the switch on the one hand and to the first external terminal on the other hand.

[0032] 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.

[0033] This offers the advantage of a flat surface contact. The heating resistor component can, for example, be mounted as a surface-mounted component in an SMD (surface-mounted device) design on the two top surfaces of the external terminals, which lie in a common plane. This ensures good electrical contact and simultaneously enables a space-saving arrangement of the heating resistor component within the switch housing.

[0034] According to a further embodiment, the first contact surface and the second contact surface of the heating resistor component are separated from each other by a gap or a contact interruption element.

[0035] The contact breaker component can, for example, be an insulator arranged in the connection plane between the two contact surfaces of the heating resistor component. However, it is generally sufficient to provide the heating resistor component with two contact surfaces on its connection side, separated by a gap and applied directly to the heating resistor material.

[0036] The heating resistor component can therefore be manufactured cost-effectively despite the relatively simple assembly and electrical contacting it offers. Accordingly, the special arrangement and electrical contacting of the heating resistor component does not increase the overall cost of the switch compared to the previously mentioned, state-of-the-art switches with a self-locking function.

[0037] According to a further embodiment, the heating resistor component rests with its first contact surface directly on the top side of the first external connection or is firmly bonded thereto by surface mounting. Likewise, according to this embodiment, the heating resistor component rests with its second contact surface directly on the top side of the second external connection or is firmly bonded thereto by surface mounting.

[0038] The electrical contact between the heating resistor component and the two external terminals of the switch can therefore be established either by 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 surfaces of the two external terminals are located.

[0039] To improve the electrical contact and mechanical attachment of the heating resistor component, the contact surfaces of the heating resistor component can alternatively be integrally connected to the respective external terminal of the switch. For example, the contact surfaces of the heating resistor component can be soldered or welded to the upper surfaces of the respective external terminal.

[0040] According to a further embodiment, the heating resistance component is pressed with its connection side against the first and second external connection by means of a compression spring.

[0041] A single compression spring thus provides the contact pressure between the heating resistor component on the one hand and both external terminals on the other. This further improves the contact between the heating resistor component and the two external terminals of the switch, while the spring force of the compression spring simultaneously prevents excessive mechanical stress from being exerted on the heating resistor component.

[0042] Unlike the switches known from DE 197 52 581 A1 and DE 198 07 288 A1, the compression spring itself does not have to act as a current-carrying component, since the current flows from one external terminal to the other external terminal immediately and directly via the heating resistor component when the switch mechanism is in the open position. 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, such as plastic. This offers further cost savings. Furthermore, the fact that as few switch components as possible are de-energized when the switch mechanism is in the open position offers another safety advantage.

[0043] Preferably, the compression spring engages the heating resistor component on an upper side of the heating resistor component opposite the connection side.

[0044] 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 thus further increases the contact pressure, whereby the force of the compression spring can act directly on the top side of the heating resistor component.

[0045] In principle, the upper side of the heating resistor component, to which the compression spring engages, 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.

[0046] 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.

[0047] This ensures, on the one hand, that the heating resistor component is electrically insulated from the switchgear. On the other hand, it also ensures that even in the event of vibration, mechanical collisions between the switchgear and the heating resistor component cannot occur. The heating resistor component is preferably arranged in a form-fitting manner in a separate chamber inside the switch housing.

[0048] Preferably, the heating resistor component comprises a PTC material.

[0049] Particularly preferably, the heating resistor component comprises a solid cuboid block made of PTC material, on one side of which, referred to herein as the "connection side", two metal contact elements are arranged at a distance from one another, on which the two contact surfaces of the heating resistor component are located.

[0050] Similar to the switching mechanism, the heating resistor component is preferably arranged in the insulating material carrier. Particularly preferably, the heating resistor component is arranged in a separate recess in the insulating material carrier, separated from the switching mechanism by at least one wall.

[0051] According to a further embodiment, the first and second external terminals are arranged parallel to one another inside and outside the insulating material carrier.

[0052] According to this design, the two external terminals are preferably routed parallel to one another at the same height through the insulating material carrier. This greatly simplifies the electrical connection of the switch, as the two external terminals run parallel to one another at the same height, similar to a plug.

[0053] According to a further embodiment, the insulating material carrier forms a lower part of the housing, which is closed by a cover part.

[0054] The cover part is preferably designed as a separate 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.

[0055] In a first alternative embodiment, the cover part is made of metal, with the cover part forming the first electrode. According to this embodiment, the cover part thus has two basic functions. Firstly, as part of the switch housing, it serves to shield the interior of the housing, which houses the switching mechanism and the insulating material carrier, 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.

[0056] 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 connecting element. Compared to the previously mentioned embodiment, in which the cover part is made of metal and forms one electrode of the switching mechanism, an additional component forming the first electrode is required. On the other hand, the housing, which has the cover part in addition to the base or insulating material support, can be made entirely of plastic, which, in particular, enables cost-effective production of the switch.

[0057] The connection plane is preferably oriented orthogonally to the vertical direction. The vertical direction is the direction along which the two electrodes of the switch are spaced from each other. The switching mechanism is arranged between the first electrode and the second electrode in the vertical direction.

[0058] 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 opposite in the vertical direction.

[0059] The first electrode is preferably arranged vertically above the switchgear, while the two external terminals, together with the second electrode, are arranged on the opposite vertical underside of the switchgear. This has the advantage that the two external terminals are routed out of the insulating material carrier as low as possible, close to the underside of the switch housing.

[0060] 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.

[0061] This allows for a very compact and vertically flat design of the switch. Furthermore, the second electrode can be integrally connected to the second external terminal, as it is located on the same connection plane. For example, the same metal sheet can be used as the second electrode and the second external terminal. This further keeps the number of switch components to a minimum and simplifies the installation of the second electrode or the second external terminal.

[0062] 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.

[0063] The temperature-dependent switching element is preferably a bimetallic or trimetallic component.

[0064] 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 terminal 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 terminal.

[0065] The provision of a spring element in addition to a temperature-dependent switching element within the switching mechanism has the advantage of electrically and mechanically relieving the temperature-dependent switching element. Furthermore, this can increase the contact pressure in the closed position of the switching mechanism, which in particular improves the switch's resistance 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 be connected mechanically and electrically in series or in parallel, as mentioned above.

[0066] 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.

[0067] Embodiments of the present invention are illustrated in the drawings and explained in more detail in the following description. They show: Fig. 1 is 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 is 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 view of an embodiment of a heating resistor component used in the switch according to the invention; Fig. 3B a plan view from below of the Fig. 3A shown heating resistor component; 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 in 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 is 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 is 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.

[0068] Fig. 1 and 2Each shows 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 reference numeral 10.

[0069] Fig. 1 shows the closed position of switch 10. Fig. 2 shows the open position of switch 10.

[0070] 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.

[0071] 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 terminal 14 and the second external terminal 16.

[0072] The first external terminal 14 is electrically connected to a first electrode 18. This first electrode 18 forms 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.

[0073] The second external terminal 16 is electrically connected to a second electrode 20. In the presently shown embodiment, the second electrode 20 is integrally connected to the second external terminal 16. In other words, one and the same metal sheet forms the second electrode 20 and the second external terminal 16.

[0074] 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.

[0075] The two electrodes 18, 20 are held apart by an insulating support 22, which forms part of the housing 24 of the switch 10. The insulating support 22 supports the two electrodes 18, 20 and fixes them in their arrangement. The two electrodes 18, 20 are therefore immobile, stationary electrodes.

[0076] The two electrodes 18, 20 are held at a distance from each other by the insulating material carrier 22 along a height direction. This height direction, which is Fig. 1 and 2 indicated by an arrow h, runs transversely, preferably orthogonally to the two electrodes 18, 20.

[0077] The first electrode 18 is arranged on an upper side (here referred to 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 (here referred to as "second side") of the switching mechanism 12.

[0078] 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 potting such that the second electrode 20 is an integral part of the housing lower part 23.

[0079] 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 by the insulating material carrier 22 along its entire circumference and is held captively to the insulating material carrier 22 or the lower part 23 by a hot-stamped upper edge.

[0080] Furthermore, a line connecting element 26 made of electrically conductive material is integrated into the insulating material carrier 22. This line connecting element 26 can be, for example, a conductive sheet or another electrical conductor that is integrated into the insulating material carrier 22 and is thus 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 connecting element 26 has an L-shaped cross-section.

[0081] The line connecting element 26 connects the first electrode 18 to the first external terminal 14. In this way, it is possible to guide the two external terminals 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 terminal 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.

[0082] The two external connections 14, 16 run as shown in Fig. 4 shown, outside the insulating material carrier 22 parallel to each other and can be arranged in a common connection plane E due to the line connecting element 16, which is in Fig. 1 and 2 indicated by a dashed line. More precisely, 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.

[0083] While the top side 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 orthogonally to the height direction h.

[0084] An electrical heating resistor component 32 rests on top of the two external terminals 14, 16. This heating resistor component 32 is electrically connected in parallel with the switching mechanism 12 and is also arranged inside the housing 24 in a separately provided recess 34 of the insulating material carrier 22, laterally adjacent to the switching mechanism 12, but spatially separated from it.

[0085] The heating resistance component 32 essentially serves the function of self-holding, with which the switch 10 is kept open after being opened by the switching mechanism 12 until the device to be protected by the switch 10 is de-energized independently of the switch 10.

[0086] The heating resistor component 32 comprises a roughly 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 formed, 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 herein as the "connection side" of the heating resistor component 32.

[0087] 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 with 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 with the second external connection 16.

[0088] The heating resistor component 32 thus rests flatly from above on the two external terminals 14, 16 of the switch 10, with the first contact surface 44 resting on the upper side 28 of the first external terminal 14 and the second contact surface 46 resting on the upper side 30 of the second external terminal 16.

[0089] To increase the contact pressure between the two contact surfaces 44, 46 and the upper sides 28, 30, the heating resistor component 32 is pressed with its connection side 42 against the two external connections 14, 16 by means of a compression spring 48. This compression spring 48 engages the heating resistor component 32 on an upper side 50 opposite the connection side 42. The heating resistor component 32 can be covered on the upper side 50 by an insulating layer 52 to electrically insulate the PTC block 36 from the compression spring 48.

[0090] To isolate the two contact elements 38, 40 from each other, a contact interruption element 54 can be arranged between them (see Fig. 3A und 3B ). Alternatively, the two contact elements 38, 40 of the heating resistor component 32 are separated from each other by a gap (air gap).

[0091] 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 is Fig. 4 is indicated by dashed lines, runs obliquely or angled to the second external connection 16, but, as already mentioned, lies together with the second external connection 16 in the connection plane E. However, the second electrode 20 does not necessarily have to run at an angle or obliquely to the second external connection 16, as is the case in Fig. 4 is shown. The second electrode 20 can in principle also be aligned with the first external terminal 16. In such a case, it is preferred that the second external terminal 16 runs together with the second electrode 20 in the radial direction of the switch housing 24. If the second external terminal 16 is centrally located, 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.

[0092] Even in Fig. 5-8 In the exemplary 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 to implement 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 basically in Fig. 3A und 3B The outlined structure of the heating resistor component 32 is therefore also applicable to the Fig. 5-8 The two shown in Fig. 5-8 The embodiments shown differ from the one in 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.

[0093] 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 bimetallic element in the form of an elongated spring tongue. The spring element 58 is made of metal and is also designed as an elongated spring tongue.

[0094] 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 in the interior of 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.

[0095] 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.

[0096] If, based on this, the temperature of the switching element 56 increases due to an increased current flow through the switch 10 or due to an increased external temperature, the creeping phase of the switching element 56 begins, in which its spring force, acting 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 by the spring element 58, so that the movable contact part 68 continues to be pressed against the stationary contact part 70.

[0097] 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.

[0098] In the Fig. 2 In the open position of the switch 10 shown, no 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 automatically heats up the heating resistor component 32. 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 effects the so-called self-holding of the switch 10, by which the switch 10 is kept permanently open until there is no longer any external voltage between the two external connections 14, 16. This is usually only the case when the device to be monitored by the switch 10 is de-energized, for example by being disconnected from the power grid.

[0099] 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 switch to the closed position shown as soon as the temperature of the device to be monitored by switch 10 and thus also the temperature of switch 10 drops again.

[0100] In the Fig. 5 and 6 In the second embodiment shown, the temperature-dependent switching behavior of the switch 10 is achieved by a structurally and functionally different switching mechanism 12. However, the previously explained principle of self-holding, which is achieved 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 also Fig. 5 and 6shown embodiment of the temperature-dependent switch according to the invention.

[0101] The rear derailleur 12 comprises Fig. 5 and 6 The switch 10 shown comprises a temperature-dependent switching element 56 and a temperature-dependent spring element 58. The switching element 56 is designed here as a disc-shaped bimetallic element, which is why it is also referred to as a bimetallic disc. The spring element 58 is also disc-shaped and preferably designed as a spring snap-action disc, which has two temperature-independent stable configurations, between which it snaps back and forth under the application of force.

[0102] The switching element 56 and the spring element 58 are in the Fig. 5 and 6The two contact elements 68 and 69 are electrically and mechanically connected in parallel to one another in the second embodiment shown. The movable contact part 68 is firmly attached to the spring element 58. The switching element 56, designed as a bimetallic disc, is placed over the movable contact part 68 with a hole 72 provided centrally therein.

[0103] The cover part 19, which, as in the first embodiment, is preferably made of metal, functions as the first electrode 18. As before, the first electrode 18 is electrically connected to the first external terminal 14 via the line connection element 26, which is embedded in the insulating material carrier 22.

[0104] 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.

[0105] 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.

[0106] In the Fig. 5 In the closed position of the switch 10 shown, the disc-shaped spring element 58 rests 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. Thus, unlike in the first embodiment, no current flows through the switching element 56 in the closed position of the switch 10.

[0107] In the closed position of the switch 10, the current flows from the first external terminal 14 via the line connecting 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 terminal 16.

[0108] 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 effected solely by the spring element 58.

[0109] 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 into 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 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.

[0110] 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 resistor component 32, which, as previously mentioned, heats up and holds the switch 10 in the open position until the power supply is completely interrupted.

[0111] In the Fig. 7 and 8In 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 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 8 shown third embodiment is designed in a disc-shaped or circular disc-shaped manner and is connected with its respective center to the movable contact part 68.

[0112] 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.

[0113] 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 8 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 house the switching mechanism 12 or the switching mechanism unit formed by the switching element 56, the spring element 58, and the movable contact part 68.

[0114] The derailleur housing 80 is designed as a partially open housing and is preferably made of metal. The derailleur unit, formed by the switching element 56, the spring element 58, and the movable contact part 68, is held captive in the derailleur housing 80 but with some play.

[0115] 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 material and then to insert it as a whole into the switch housing 24.

[0116] In the Fig. 7 In the closed position of the switch shown, the spring element 58 is supported with its outer edge 74 on the inside of the switching mechanism housing 80 and presses the movable contact part 68 against the stationary contact part 70. In this embodiment of the switching mechanism 12, the switching element 56 is also mechanically mounted without force in the closed position of the switch 10 and no current flows through it.

[0117] In the Fig. 7 and 8 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, for example of a similar or even the same material as the insulating material carrier 22, which forms the lower part 23 of the housing 24.

[0118] If the cover part 19 is made of plastic, the heating resistor component 32 does not need to be electrically insulated from the compression spring 48, which is why the insulation layer 52 can be omitted. Here, too, the heating resistor component 32, with its contact surfaces 44, 46 provided on the bottom or connection side 42, lies directly against the top sides 28, 30 of the external connections 14, 16.

[0119] 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 internally in the switch establishes the electrical contact between the first electrode 18 and the first external terminal 14 and enables the two external terminals 14, 16 to be attached at the same height or the external terminals 14, 16 to be led out of the insulating material carrier 22 at the same height.

[0120] The current flow in the Fig. 7 The closed position of the switch shown is from the first external terminal 14 via the line connecting 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.

[0121] 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 switchgear housing 80 and pushes the movable contact part 68 upwards, whereby the movable contact part 68 is lifted from the stationary contact part 70 and the current flow through the switchgear 12 is interrupted. As a result, the spring element 58 also snaps from its Fig. 7 shown concave position in its Fig. 8 shown convex position.

[0122] 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 terminals 14, 16.

[0123] 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 switch interior are implemented in a fundamentally similar manner in all three exemplary embodiments.

Claims

1. A temperature-dependent switch (10), having a housing (24) and a temperature-dependent switching mechanism (12) arranged therein, which is configured 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 terminal (14) and a second external terminal (16), and an open position, in which the temperature-dependent switching mechanism (12) disconnects the electrically conductive connection, wherein the two external terminals (14, 16) are led parallel alongside each other out of the housing (24) in such a way that an upper side (28) of the first external terminal (14) lies with an upper side (30) of the second external terminal (16) in a common connection plane (E), and wherein arranged inside the housing (24) is an electrical heating resistor component (32), which is electrically connected in parallel with the switching mechanism (12) and has on a connection side (42) a first contact area (44), which electrically contacts the upper side (28) of the first external terminal (14), and a second contact area (46), which electrically contacts the upper side (30) of the second external terminal (16), wherein the housing (24) comprises an insulating material carrier (22), which carries a first stationary electrode (18) electrically connected to the first external terminal (14) and a second stationary electrode (20) electrically connected to the second external terminal (16), 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), characterized in that the insulating material carrier (22) keeps the first stationary electrode (18) and the second stationary electrode (20) at a distance from each other along a vertical direction (h), in that the first electrode (18) is electrically connected to the first external terminal (14) by way of a line connecting element (26) aligned transversely in relation to the two electrodes (18, 20) and arranged in the housing (24), and in that the first and the second external terminal (14, 16) are led through the insulating material carrier (22) at the same height with respect to the vertical direction (h).

2. The temperature-dependent switch according to claim 1, wherein the first contact area (44) and the second contact area (46) lie in a common contact plane (K) which is aligned parallel to the connection plane (E) or coincides with the connection plane (E).

3. The temperature-dependent switch according to claim 1 or 2, wherein the first contact area (44) and the second contact area (46) are separated from each other by a gap or a contact interruption element (54).

4. The temperature-dependent switch according to one of claims 1-3, wherein the heating resistor component (32) lies with its first contact area (44) directly on the upper side (28) of the first external terminal (14) or is fastened to it with a material bond by means of surface mounting, and wherein the heating resistor component (32) lies with its second contact area (46) directly on the upper side (30) of the second external terminal (16) or is fastened to it with a material bond by means of surface mounting.

5. The temperature-dependent switch according to one of claims 1-4, wherein the heating resistor component (32) is pressed with its connection side (42) against the first and the second external terminal (14, 16) with the aid of a compression spring (48).

6. The 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 from the connection side (32).

7. The temperature-dependent switch according to one of claims 1-6, wherein the heating resistor component (32) is spatially separated from the switching mechanism (12) by at least one wall (65) inside the housing (24).

8. The temperature-dependent switch according to one of claims 1-7, wherein the heating resistor component (32) comprises a PTC material.

9. The temperature-dependent switch according to one of claims 1-8, wherein the first and the second external terminal (14, 16) are arranged parallel alongside each other inside and outside the insulating material carrier (22).

10. The temperature-dependent switch according to one of claims 1-9, 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.

11. The temperature-dependent switch according to one of claims 1-10, wherein the connection plane (E) is aligned orthogonally in relation to the vertical direction (h).

12. The temperature-dependent switch according to one of claims 1-11, 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) lying opposite in the vertical direction (h).

13. The temperature-dependent switch according to one of claims 1-12, wherein the temperature-dependent switching mechanism (12) has a temperature-dependent switching element (56), which is configured to change its geometric shape depending its temperature in order to switch the switching mechanism (12) between the closed position and the open position.

14. The temperature-dependent switch according to one of claims 1-13, wherein the temperature-dependent switching mechanism (12) has a spring element (58), which is configured to produce the electrically conductive connection in the closed position of the switching mechanism (12), by being electrically conductively connected to the first external terminal (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) electrically conductively connected to the second external terminal (16).

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