Temperature-dependent switch

Abstract

A temperature-dependent switch (100) comprises a temperature-dependent switching mechanism (10) with a switching mechanism unit (14) having a movable contact portion (22) coupled to a bimetallic pressure disc (18), and a switching mechanism housing (16) in which the switching mechanism unit (14) is arranged and housed. The switch (100) further comprises a switch housing (12) in which the switching mechanism housing (16) is arranged and housed, and the switch housing (12) has a fixed contact portion (32) acting as a coupling contact with the movable contact portion (22).The switching mechanism housing (16) has a first conductive base body (36), and the switching mechanism (10) is configured to hold the switch (100) in a low-temperature position below the response temperature of the bimetallic disc (18). The switching mechanism (10) establishes a first electrical connection between the first base body (36) and the fixed contact portion (32) via the moving contact portion (22). When the response temperature is exceeded, the switching mechanism (10) moves the switch (100) to a high-temperature position, at which point it breaks the first electrical connection. The switch (100) also has a PTC component (46) that is electrically connected in parallel to the first electrical connection.

Description

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

[0002] Temperature-dependent switches are already known in many forms. An example of a temperature-dependent switch is disclosed in DE 10 2013 102 006 A1.

[0003] Such temperature-dependent switches serve, in a manner known per se, 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 typically connected electrically in series in the supply circuit of the device to be protected via connecting leads, so that below the switch's response temperature the supply current of the device to be protected flows through the switch.

[0005] The switch known from DE 10 2013 102 006 A1 has a switch housing in which a switching mechanism is hermetically sealed. The switch housing is constructed in two parts. It comprises a lower part made of electrically conductive material and a cover part made of an insulating material or a PTC thermistor. The cover part is inserted into the lower part and held in place by an upper, folded edge of the lower part. The switching mechanism is clamped between the cover part and the lower part. During the manufacturing process, the switching mechanism is first loosely inserted into the lower part. The cover part is then placed on top and firmly connected to the lower part.

[0006] The temperature-dependent switching mechanism housed within the switch casing features a bimetallic snap disc attached to a movable contact element. This bimetallic snap disc is responsible for the switch's temperature-dependent switching behavior. At low temperatures, it ensures that the switching mechanism establishes an electrically conductive connection between the movable contact element and a stationary contact element located on the cover, which acts as the mating contact to the movable contact element. At higher temperatures, however, the bimetallic snap disc interrupts this electrical contact by lifting the movable contact element away from the stationary contact element.

[0007] The bimetallic snap disc is usually designed as a multi-layered, active, sheet-like component consisting of two, three, or four interconnected components with different coefficients of thermal expansion. The connections between the individual layers of metals and metal alloys in such bimetallic snap discs are usually material-bonded or form-fitted and are achieved, for example, by rolling.

[0008] Such a bimetallic snap disc exhibits a first stable geometric configuration (low-temperature configuration) at low temperatures, below the response temperature of the bimetallic snap disc, and a second stable geometric configuration (high-temperature configuration) at high temperatures, above the response temperature of the bimetallic snap disc. The bimetallic snap disc switches from its low-temperature configuration to its high-temperature configuration depending on the temperature, following a hysteresis-like process. This process is often referred to as "snapping," which also explains the name "snap disc."

[0009] Unless a reset lock is provided, the bimetallic snap disc snaps back into its low-temperature configuration, so that the switch closes again when the temperature of the bimetallic snap disc drops below the so-called return temperature of the bimetallic snap disc as a result of the cooling of the device to be protected.

[0010] Depending on the application, such a reset may be undesirable. For safety reasons, for example, it may be necessary for the switch to be designed so that it does not automatically close again after opening due to temperature changes, once the protected device has cooled down. For instance, the switch should only close again after the protected device has not only cooled down but has also been completely disconnected from the power supply.

[0011] For such cases, a so-called self-holding function was developed. In the switch known from DE 10 2013 102 006 A1, this self-holding function is achieved by the fact that the cover part of the switch is made of a PTC material (Positive Temperature Coefficient Thermistor).

[0012] As long as the switch is in its low-temperature position and closed, no current flows through the PTC element connected in parallel as a resistor. However, when the switch opens, a small holding current flows through the parallel resistor, heating it and ensuring that the switch remains at a temperature above the response temperature of the bimetallic snap disc. This holding current is so low that the protected electrical device suffers no further damage and can cool down. The holding resistance created by the PTC element prevents the switch itself from cooling down and re-engaging, which, without the parallel resistor, would result in the protected electrical device cycling on and off repeatedly.

[0013] The switch known from DE 10 2013 102 006 A1 has a manufacturing disadvantage. This disadvantage stems from the fact that the bimetallic snap disc, together with the movable contact element, is inserted into the switch housing as a loose component. Only when the switch housing is closed is the bimetallic snap disc fixed in its position and its position relative to the other components of the switching mechanism determined. However, the positioning of such a switch, in which the bimetallic snap disc is inserted separately, has proven to be relatively cumbersome, as several steps are necessary to insert the switching mechanism into the switch housing.

[0014] Furthermore, storing the switching mechanism or its individual components is cumbersome. Bulk storage of the switching mechanism components is hardly feasible, for example, as these components, especially the bimetallic snap disc, are relatively susceptible to damage. If such damage occurs during storage, the resulting malfunction of the switching mechanism is usually only detected once the switch is assembled, since a functional test of the switching mechanism beforehand is virtually impossible.

[0015] DE 195 27 253 A1 discloses a modular temperature monitor comprising a bimetallic switching mechanism that protects a load from excessive temperature. Furthermore, a first electrical component associated with the bimetallic switching mechanism is provided, which, when the bimetallic switching mechanism is open, is connected in series between the terminals of the temperature monitor. A second electrical component associated with the bimetallic switching mechanism is connected in series with it, at least when the bimetallic switching mechanism is closed, between the terminals of the temperature monitor. The first component is designed as a heating resistor or an insulator, with a comparable mechanical structure.The second component, with a comparable mechanical design, is configured as a series resistor or a short-circuiting element, so that, with the same mechanical design, temperature monitors with pure over-temperature protection, with over-temperature protection and self-holding function, with over-temperature protection and current sensitivity, or with over-temperature protection, self-holding function and current sensitivity are provided.

[0016] DE 10 2013 017 232 A1 discloses a temperature-dependent switching mechanism with a bimetallic snap disc and a spring-loaded snap disc, the latter carrying a movable contact element. The bimetallic snap disc and the spring-loaded snap disc are captive and held in place by an annular frame.

[0017] It is therefore an object of the present invention to provide a temperature-dependent switch with a self-holding function that is easier to manufacture overall. Among other things, it would be desirable if the switching mechanism could be pre-produced as a semi-finished product without being susceptible to damage. Furthermore, it would be desirable if a functional test of the switching mechanism could be performed before its final installation in the switch. In addition, the switch should be relatively easy to mount, have a low profile, and be pressure-resistant.

[0018] This problem is solved according to the invention by a temperature-dependent switch which comprises the following components: a temperature-dependent switching mechanism with a switching unit comprising a movable contact part coupled to a bimetallic snap disc, and with a switching unit housing in which the switching unit is arranged and captive therein; and a switch housing in which the switching unit housing is arranged and captive therein, wherein the switch housing has a stationary contact part that acts as a mating contact to the movable contact part; wherein the switching mechanism housing surrounds the switching mechanism unit from a first housing side, a second housing side opposite the first housing side, and a housing circumferential side extending between and transversely to the first and second housing sides, and having an opening on the first housing side through which the movable contact part interacts with the stationary contact part, wherein the switching mechanism housing has an electrically conductive first base body, and wherein the switching mechanism is configured to hold the switch in a low-temperature position below a response temperature of the bimetallic snap disc, in which the switching mechanism establishes a first electrical connection between the first base body and the stationary contact part via the movable contact part, and upon exceeding the response temperature, to move the switch into a high-temperature position in which the switching mechanism breaks the first electrical connection.wherein the switch further comprises a PTC component which is electrically connected in parallel to the first electrical connection, and wherein the switching mechanism housing is designed as a single piece and / or the electrically conductive first body of the switching mechanism housing forms at least a part of the second housing side of the switching mechanism housing, wherein this part of the second housing side forms a freely accessible outer surface of the switch.

[0019] Similar to the switch known from DE 10 2013 102 006 A1, the switch according to the invention also has a PTC component (positive temperature coefficient thermistor) that is electrically connected in parallel to the switching mechanism. More precisely, the PTC component is electrically connected in parallel to the first electrical connection, which is made by the switching mechanism in the low-temperature position of the switch. The PTC component thus performs a self-holding function of the switch, which, after an initial temperature-related opening, keeps the switch in its high-temperature position, in which the switching mechanism interrupts the first electrical connection, even when the device to be protected by the switching mechanism cools down again. In the high-temperature position of the switch, current flows through the PTC component, which is consequently heated.The heat generated in this process, as with the switch known from DE 10 2013 102 006 A1, causes the switching mechanism to not cool down and consequently not to close the switch again or return it to its low-temperature position.

[0020] In contrast to the switch known from DE 10 2013 102 006 A1, the switch according to the invention has a significantly simpler design. In particular, its assembly can therefore be carried out more easily, in fewer steps.

[0021] The switch according to the invention comprises a switching mechanism which has an additional switching mechanism housing in which the switching mechanism unit, comprising the bimetallic snap disc and the movable contact element, is captive. The switching mechanism housing surrounds the switching mechanism unit from a first housing side, from a second housing side opposite the first housing side, and from a circumferential housing side extending between and transversely to the first and second housing sides. The switching mechanism housing thus surrounds the switching mechanism unit at least partially from all six spatial directions, so that the switching mechanism cannot fall out of the switching mechanism housing.

[0022] The switching mechanism, including the switching unit and the housing surrounding it, can therefore be pre-produced as a semi-finished product before being installed in the switch housing. This pre-produced switching mechanism can be stored in bulk. During this bulk storage, the various components of the switching unit, especially the bimetallic snap disc and the movable contact element, are protected by the switching unit housing. Damage to these components during bulk storage is largely prevented because the various components of the switching unit are securely encapsulated within the housing.

[0023] The switching mechanism housing not only offers the advantage of securely containing the switching unit, but also enables a significantly simpler manufacturing process for the temperature-dependent switch. Unlike a conventional switch housing, the newly provided switching mechanism housing is not a completely closed enclosure in which the switching mechanism is hermetically sealed, but rather a partially open housing with an opening on the front side through which the moving contact element is accessible from outside the housing. The switching mechanism, along with the switching mechanism housing, can thus be inserted as a single unit into a simplified outer switch housing, which forms the final switch housing.

[0024] In the manufacture of the temperature-dependent switch, the switching mechanism according to the invention, including its switching mechanism housing, can first be pre-produced as a semi-finished product and then inserted as a whole into the switch housing. This significantly simplifies not only the warehousing of the switching mechanism but also the manufacturing of the temperature-dependent switch.

[0025] As already mentioned, the derailleur housing is a partially open housing. While the second housing side and the outer side of the derailleur housing are preferably closed housing sides, the first housing side, due to the aforementioned opening, is only partially closed or partially open.

[0026] The partially open first side of the switch housing is concealed by the switch housing, which serves as the switch base. The movable contact element interacts directly with the stationary contact element, located on the switch housing, through the opening in the switch housing. In the low-temperature position of the switch, the movable contact element touches the stationary contact element through the opening in the switch housing.

[0027] The result is a simple switch constructed from relatively few components, which can be manufactured in comparatively few steps. The switching mechanism used in the switch can be pre-produced together with the switching mechanism housing and stored in bulk. The switch housing, consisting of the switch housing and switching mechanism housing, is relatively pressure-resistant and can still be relatively compact and space-saving. The PTC component enables a latching function of the switch, preventing it from switching back to the low-temperature position after an initial switch to the high-temperature position, as long as a voltage is applied to the switch or the device it is protecting.

[0028] The aforementioned part of the first base body, which forms part of the second housing side of the switchgear housing, is not enclosed by the switch housing when the switch is fully assembled. Therefore, this part of the switchgear housing can serve as the direct external electrical connection surface of the switch.

[0029] According to the second alternative, the switchgear housing is remarkably simple, consisting of only one part. It is preferably made of metal. This metal forms the electrically conductive first base body, which at least partially surrounds the switchgear unit on all sides and has the aforementioned opening on the first side of the housing.

[0030] According to one embodiment, the PTC component is arranged in the switch housing.

[0031] This not only has the advantage of a compact switch design, but also the advantage that the PTC component is ideally protected inside the switch.

[0032] According to a further embodiment, the switch housing has an electrically conductive second base body which is connected to the first base body via the PTC component, wherein the second base body surrounds the first housing side and the housing circumference side of the switch housing.

[0033] The switchgear housing is preferably made of an electrically conductive material. In other words, the first basic body preferably forms the switchgear housing.

[0034] The switch housing is preferably made of an electrically conductive material. In other words, the second basic body preferably forms the switch housing.

[0035] Both the switch housing and the switching mechanism housing can thus function as the external electrical terminals of the switch. As long as the switch is in its low-temperature position, the current flows from the switch housing via the switching mechanism to the switching mechanism housing, or vice versa, from the switching mechanism housing via the switching mechanism to the switch housing.

[0036] When the switch is open, i.e., in the high-temperature position of the switch, the first electrical connection through the switching mechanism is interrupted, so that the electrical current between the switch housing and the switching mechanism housing can only flow via the PTC component.

[0037] Since the PTC component is already heated in this case, it exhibits a relatively high resistance, so only a very small holding current can flow through the PTC component and thus through the switch. At the same time, this causes the PTC component to heat up further, keeping the switch in its high-temperature position.

[0038] According to a further embodiment, the switchgear housing rests against the PTC component with its first housing side.

[0039] Preferably, the switch housing rests on the PTC component with its first side facing upwards. The PTC component forms an intermediate layer positioned between the switch housing and the switch housing. This results in a very compact and extremely pressure-resistant switch design.

[0040] The aforementioned part of the first base body of the switch housing, which forms a freely accessible outer surface of the switch, preferably has an outwardly convex, dome- or cup-shaped section. This dome- or cup-shaped section of the switch housing preferably projects at least partially out of the switch housing. "Outwardly convex" in this context means that the dome- or cup-shaped section is convex from the perspective of the switch housing, i.e., protruding from the interior of the switch housing. The outer surface of the switch is convex at this point.

[0041] This design of the switch housing makes the switch extremely pressure-resistant. Furthermore, the dome- or cup-shaped section can be very easily used as the external connection surface of the switch.

[0042] According to a further embodiment, the temperature-dependent switch also has an insulator that is arranged between the first base body and the second base body and is in contact with both the first base body and the second base body.

[0043] This insulator electrically isolates the two base bodies from each other. The insulator ensures that an electrically conductive connection is established between the two base bodies via the switching unit in the low-temperature position of the switch. In the high-temperature position of the switch, the two electrically conductive base bodies are only connected to each other via the PTC component; otherwise, they are electrically isolated from each other.

[0044] According to a further embodiment, the insulator has a ring body which, with its inner side, rests against the housing circumference side of the switchgear housing and with its outer side rests against an inner circumferential surface of the switch housing.

[0045] Preferably, the insulator is designed as a ring body. Viewed from above, this ring body can be circular. However, viewed from above, the ring body can also have a polygonal outer contour.

[0046] The term "ring body" is therefore to be understood generally. It refers to any body that has a closed circumferential contour. Thus, the outer contour viewed from above can, for example, be elliptical or have any freeform shape. The ring body does not necessarily have to be hollow cylindrical or torus-shaped, although this is preferred.

[0047] Designing the insulator as a ring body has the advantage that the insulator electrically isolates the switching mechanism housing from the switch housing all around its circumference. Furthermore, such a ring body can be arranged in the switch housing in a space-saving manner. The ring body is also preferably solid, so that the insulator forms a mechanically stable component of the switch, which can also serve to support other components of the switch and is easy to handle during switch assembly. The ring body of the insulator thus automatically ensures correct alignment of the switching mechanism, in particular the associated movable contact part, with respect to the stationary contact part located on the switch housing.

[0048] The ring body of the insulator preferably rests with its underside against the PTC component. During switch assembly, the ring body of the insulator is preferably placed on the PTC component before the switching mechanism housing is inserted into the switch housing. As already mentioned, it ensures correct alignment of the switching mechanism housing relative to the switch housing during assembly.

[0049] According to a further embodiment, the diameter of the opening is smaller than the diameter of the bimetallic snap disc measured parallel to it.

[0050] The bimetallic snap disc is therefore securely held in the derailleur housing and cannot come loose even under significant vibration.

[0051] According to a further embodiment, the bimetallic snap disc is designed to snap from a geometrically stable low-temperature configuration to a geometrically stable high-temperature configuration when the response temperature is exceeded, wherein the bimetallic snap disc in its high-temperature configuration is supported on a support surface arranged on the first housing side of the switchgear housing, which is formed on the first base body, and thereby keeps the movable contact part at a distance from the stationary contact.

[0052] Since the switching mechanism unit according to the present invention is encapsulated in the switching mechanism housing and the bimetallic snap disc, in its high-temperature configuration, is supported on the aforementioned support surface inside the switching mechanism housing, a functional test of the switching mechanism can be performed even on the semi-finished switching mechanism, i.e., before the switching mechanism is installed in the switch housing and the switch is completely assembled. This is because the bimetallic snap disc can already assume its two temperature-dependent configurations inside the switching mechanism housing at this stage.

[0053] This is not possible with conventional switches, as the bimetallic snap disc, due to the absence of the now extra switch housing, rests against the switch housing in its high-temperature configuration, meaning that a functional check is only possible when the switch is fully assembled.

[0054] According to a further embodiment, the switching unit also has a spring-loaded snap disc coupled to the movable contact part, which, in the low-temperature position of the switch, is supported on an inner surface located on the second side of the housing inside the switching unit housing. This inner surface is preferably an inner surface of the electrically conductive first base body of the switching unit housing.

[0055] The additional provision of such a spring-loaded snap disc has the particular advantage of relieving the stress on the bimetallic snap disc. In the low-temperature position of the switch, i.e., when the circuit above the switch is closed, the spring-loaded snap disc, according to this design, serves as a current-carrying component. The bimetallic snap disc, on the other hand, is then not a current-carrying component.

[0056] Furthermore, in the low-temperature position of the switch, the spring-loaded snap disc generates the closing pressure that presses the moving contact part against the stationary contact part. In contrast, the bimetallic snap disc can be mounted with virtually no force in the low-temperature position of the switch. This has a positive effect on the service life of the bimetallic snap disc and ensures that the switching point, i.e., the response temperature of the bimetallic snap disc, does not change even after many switching cycles.

[0057] According to a further embodiment, a circumferential gap between the switchgear housing and the switch housing is filled with insulating compound. Preferably, the insulating compound is a lacquer with which the gap between the switchgear housing and the switch housing is poured.

[0058] This provides an extremely good seal for the switch interior, where the switching mechanism is located. Furthermore, the insulating and sealing compound ensures a mechanically stable mounting of the switching mechanism housing within the switch housing.

[0059] It is understood that the features mentioned above and those to be explained below can be used not only in the combinations specified, but also in other combinations or on their own, without leaving the scope of the present invention.

[0060] An embodiment of the invention is shown in the drawings and is explained in more detail in the following description. The drawings show: Fig. 1 is a schematic sectional view of the temperature-dependent switch according to an embodiment of the present invention, wherein the switch is shown in its low-temperature position; and Fig. 2 is a schematic sectional view of the Fig. 1 shown switch, with the switch shown in its high-temperature position.

[0061] Fig. 1-2 Figure 1 shows an embodiment of the switch according to the invention in a schematic sectional view. The switch as a whole is marked with the reference numeral 100.

[0062] The switch 100 has a temperature-dependent switching mechanism 10, which is arranged in an electrically conductive switch housing 12.

[0063] The switching mechanism 10 comprises a functional switching unit 14 and a switching unit housing 16 surrounding this switching unit 14. The switching unit housing 16 surrounds the switching unit 14 at least partially in all six spatial directions.

[0064] As explained in detail below, the switching mechanism housing 16 is designed as a partially open housing, so that the switching mechanism unit 14 is accessible from outside the switching mechanism housing 16 from at least one spatial direction, preferably from only one spatial direction.

[0065] Because the switching mechanism housing 16 at least partially surrounds the switching mechanism unit 14 on all six spatial dimensions, the switching mechanism unit 14 is held securely in the switching mechanism housing 16. Therefore, the switching mechanism unit 14 cannot detach from the switching mechanism housing 16.

[0066] As long as the switching mechanism 10 is not installed in the switch 100 or its switch housing 12, there is preferably a certain amount of play between the switching mechanism unit 14 and the switching mechanism housing 16. In the Fig. 1 In the installed state of switch 100 shown, the switching unit 14 is firmly clamped. In the Fig. 1 In the low-temperature position of switch 100 shown, the switching unit 14 is clamped between the switch housing 12 and the switching unit housing 16.

[0067] The switching unit 14, according to the present embodiment, is composed of three parts. The switching unit 14 comprises a temperature-dependent bimetallic snap disc 18, a temperature-independent spring-loaded snap disc 20, and a movable contact element 22. The bimetallic snap disc 18 and the spring-loaded snap disc 20 are captive and held in place on the contact element 22. The switching unit 14 can therefore be prefabricated as a semi-finished product and then inserted as a complete unit into the switching unit housing 16.

[0068] The switching mechanism 10, together with the switching unit 14 and the switching unit housing 16, also constitutes a semi-finished product for the temperature-dependent switch 100 that will later be produced from it. Since both the three components 18, 20, 22 of the switching unit 14 are captive connected to each other, and the switching unit 14 is also captive held in the switching unit housing 16, the switching mechanism 10 can be stored as bulk material until it is installed in the temperature-dependent switch 100.

[0069] The derailleur housing 16 surrounds the derailleur unit 14 with a first housing side 24, a second housing side 26 opposite the first housing side 24 and a housing circumferential side 28 running between and transversely to the first and the second housing side 24, 26.

[0070] Preferably, the derailleur housing 16 completely surrounds the derailleur unit 14 on both the second housing side 26 and the housing circumferential side 28. The second housing side 26 and the housing circumferential side 28 thus preferably form closed housing sides of the derailleur housing 16. Only the first housing side 24 is a partially open housing side of the derailleur housing 16.

[0071] In other words, the housing circumference 28 surrounds the switching unit 14 along its entire circumference, i.e., from a total of four mutually orthogonal spatial directions. Furthermore, the switching unit housing 16 completely surrounds the switching unit 14 from another spatial direction, namely from a spatial direction orthogonal to the second housing side 26. Only from the sixth spatial direction, which is orthogonal to the first housing side 24, does the switching unit housing 16 only partially surround the switching unit 14.

[0072] On the first housing side 24, the switching mechanism housing 16 has an opening 30 through which the movable contact part 22 is accessible from outside the switching mechanism housing 16. Through this opening 30 in the switching mechanism housing 16, the movable contact part 22 of the switching mechanism 10 interacts with a stationary contact part 32. The stationary contact part 32 is arranged on an inner surface 34 of the switch housing 12.

[0073] In the Fig. 1 In the illustrated embodiment, the stationary contact part 32 is formed integrally with the switch housing 12. However, it would also be possible to provide the stationary contact part 32 as a type of rivet, which is connected to the switch housing 12 as a separate component. The only important thing is that an electrically conductive connection is established between the switch housing 12 and the stationary contact part 32.

[0074] The diameter D1 of the opening 30 is smaller than the parallel diameter D2 of the bimetallic snap disc 18 and / or the spring snap disc 20. Thus, although the movable contact part 22 is accessible from outside the switchgear housing 16 through the opening 30, the bimetallic snap disc 18 and the spring snap disc 20 cannot detach from or emerge from the switchgear housing 16.

[0075] The switchgear housing 16 has a base body 36 made of an electrically conductive material, for example, metal. This base body 36 is referred to here as the "first base body". In the embodiment shown here, the electrically conductive first base body 36 forms the entire switchgear housing 16. In this embodiment, the switchgear housing 16 is therefore made in one piece from an electrically conductive material.

[0076] An upper part of the first base body 36, which forms the second housing side 26, simultaneously forms a freely accessible outer surface of the switch 100. The first housing side 24 and the housing perimeter side 28 are arranged completely inside the switch housing 12 and are therefore not accessible from outside the switch 100.

[0077] The switch housing 12 consists of an electrically conductive second base body 38. The second base body 38 is preferably also made of metal. The second base body 38 forms the lower part of the switch 100, in which the other components of the switch 100 are arranged.

[0078] The second base body 38 is preferably cup-shaped. An upper edge 40 of the raised, circumferential wall 42 of the second base body 38 of the switch housing 12 is folded or crimped towards the center of the switch 100 so that the switching mechanism 10 is captive within the switch housing 12. The circumferential gap between the switching mechanism housing 16 and the switch housing 12 is filled with an insulating compound 44. The insulating compound 44 is preferably an impregnating lacquer, which is poured into the gap between the switch housing 12 and the switching mechanism housing 16 at the end of the assembly of the switch 100.

[0079] The insulating compound 44 ensures, on the one hand, that the switching mechanism housing 16 is fixed within the switch housing 12. On the other hand, the insulating compound 44 provides a mechanical seal that prevents liquids or contaminants from entering the interior of the switch 100 from the outside. In this way, a sealed switch housing 12 is created in which the switching mechanism housing 16 is held securely.

[0080] A PTC component 46 is also arranged in the switch housing 12. This PTC component 46 is a thermistor material whose electrical resistance increases with increasing temperature. The PTC component 46 is designed in the shape of a plate or disc. The PTC component 46 is inserted into the switch housing 12 and surrounds the stationary contact part 32.

[0081] The switching mechanism housing 16 rests with its first housing side 24 flush against the PTC component 46. The electrically conductive first base body 36 of the switching mechanism housing 16 is thus connected via the PTC component 46 to the electrically conductive second base body 38 of the switch housing 12.

[0082] An insulator 48 rests on the PTC component 46. This insulator 48 is designed as a ring body 50, which is arranged between the first base body 36 of the switching mechanism housing 16 and the second base body 38 of the switch housing 12 and rests against both base bodies 36 and 38. More precisely, the inner surface 52 of the ring body 50 of the insulator 48 rests against the circumferential side 28 of the switching mechanism housing 16, and its outer surface 54 rests against an inner circumferential surface 56 of the switch housing 12.

[0083] The insulator 48 is preferably designed as a plastic insulator. Besides its function of insulating the outer surface 28 of the switching mechanism housing 16 from the inner surface 56 of the switch housing 12, the insulator 48 also ensures correct alignment of the switching mechanism 10 relative to the switch housing 12 and / or of the switching mechanism 10 relative to the stationary contact part 32. The shape of the ring body 50 of the insulator 48 is preferably adapted to the shape of the switch housing 12. The ring body 50 is therefore preferably designed as a circular ring.

[0084] Since the second base body 38 of the switch housing 12 and the first base body 36 of the switchgear housing 16 are each made of electrically conductive material, thermal contact can be established via their outer surfaces with a device to be protected.

[0085] The outer surfaces of the two base bodies 36, 38 also serve as the electrical connection for the switch 100. For example, the outer surface 58 of the second base body 38 of the switch housing 12 can function as the first electrical connection, and the outer surface 60 of the first base body 48 of the switch housing 16 can function as the second electrical connection. More precisely, the outer surface 60 of the part of the base body 38 of the switch housing 16 that protrudes from the switch housing 12 can function as the second electrical connection.

[0086] This part of the switchgear housing 16, which forms a freely accessible outer surface of the switch 100, has a dome-shaped section 62 in the embodiment shown here. This dome-shaped section 62, whose upper surface is convex, ensures an extremely pressure-resistant design of the switch 100. Instead of a dome-shaped section 62, this section of the switchgear housing 16 can also be cup-shaped.

[0087] In the Fig. 1 In the low-temperature position of the switch 100 shown, the temperature-independent spring-loaded snap disc 20 is in its first configuration and the temperature-dependent bimetallic snap disc 18 is in its low-temperature configuration. The spring-loaded snap disc 20 presses the movable contact part 22 against the stationary contact part 32, which acts as the mating contact. The switch 100 is thus in its closed position, in which an electrically conductive connection is established between the outer surface 60 of the switch housing 16 and the outer surface 58 of the switch housing 12 via the spring-loaded snap disc 20, the movable contact part 22, and the stationary contact part 32.

[0088] The contact pressure between the movable contact part 22 and the stationary contact part 32 is generated by the spring-loaded snap disc 20. In the low-temperature position of the switch 100, the spring-loaded snap disc 20 is supported against an inner surface 64 located on the second housing side 26 inside the switch housing 16. In this state, the bimetallic snap disc 18 is mounted in the switch housing 16 with virtually no force acting upon it.

[0089] If the temperature of the device to be protected, and thus the temperature of the switch 100 and the bimetallic snap disc 18 located therein, rises to the switching temperature of the bimetallic snap disc 18 or above this switching temperature, the bimetallic snap disc 18 snaps from its position in Fig. 1 shown concave low-temperature configuration in their Fig. 2 The convex high-temperature configuration shown is transformed. During this snapping action, the bimetallic snap disc 18 rests with its outer edge 66 against one of the first housing sides 24 of the switchgear housing 16. This simultaneously bends the spring snap disc 20 upwards at its center, so that the spring snap disc 20 is released from its position in Fig. 1 shown, first stable geometric configuration in their in Fig. 2 The second geometrically stable configuration shown flips over.

[0090] Fig. 2 Figure 1 shows the high-temperature position of switch 100, in which it is open. The electrically conductive connection between the switch housing 12 and the switchgear housing 16, which in the low-temperature position of switch 100 is made via the switchgear unit 14, is shown in Figure 1. Fig. 2 The high-temperature position of switch 100 shown is interrupted. The switch housing 12 is then "only" connected to the switchgear housing 16 via the PTC component 46.

[0091] In the high-temperature position of switch 100, the PTC component 46 already has a relatively high electrical resistance due to the high temperature. Therefore, only a small residual current can flow from the electrically conductive switch housing 12, through the PTC component 46, into the electrically conductive switch housing 16. This residual current is harmless to the device being protected. However, the residual current heats up the PTC component 46, which in turn heats up the entire switch 100. This also keeps the bimetallic snap disc 18 at a temperature above its switching temperature, so that switch 100 is no longer closed via the switch unit 14.

[0092] Only when the device to be protected is de-energized, i.e., when no current flows through switch 100, does the PTC component 46, and thus the entire switch 100, cool down. As soon as the switching unit 14 reaches a temperature below the response temperature of the bimetallic snap disc 18, the bimetallic snap disc 18 then snaps back out of its position. Fig. 2 high-temperature configuration shown in its Fig. 1 The low-temperature configuration shown is changed, which closes switch 100 again.

[0093] Finally, it should be noted that the spring-loaded snap disc 20 is not strictly necessary. The switching unit 14 can also be implemented without the spring-loaded snap disc 20. In such a case, the switching unit 14 then "only" has the bimetallic snap disc 18 and the movable contact part 22. The bimetallic snap disc 18 then not only ensures the switching behavior of the switch 100, but also simultaneously generates contact pressure between the movable contact part 22 and the stationary contact part 32 in the low-temperature position of the switch 100. The bimetallic snap disc 18 is thus used as a current-carrying component of the switching mechanism 10.

Claims

1. A temperature-dependent switch (100), comprising: a temperature-dependent switching mechanism (10) having a switching mechanism unit (14), which comprises a movable contact part (22) coupled to a bimetallic snap-action disc (18), and having a switching mechanism housing (16), in which the switching mechanism unit (14) is arranged and held captively therein; and a switch housing (12), in which the switching mechanism housing (16) is arranged and held captively therein, wherein the switch housing (12) comprises a stationary contact part (32), which acts as a mating contact to the movable contact part (22); wherein the switching mechanism housing (16) surrounds the switching mechanism unit (14) from a first housing side (24), a second housing side (26) opposite the first housing side (24), and a housing circumferential side (28) extending between and transversely to the first and the second housing sides (24, 26), and on the first housing side (24) comprises an opening (30) through which the movable contact part (22) interacts with the stationary contact part (32), wherein the switching mechanism housing (16) comprises an electrically conductive first base body (36) and the switching mechanism (10) is configured so as, below a response temperature of the bimetallic snap-action disc (18), to keep the switch (100) in a low-temperature position in which the switching mechanism (10) establishes a first electrical connection via the movable contact part (22) between the first base body (36) and the stationary contact part (32), and, if the response temperature is exceeded, to move the switch (100) into a high-temperature position in which the switching mechanism (10) interrupts the first electrical connection, and wherein the switch (100) further comprises a PTC component (46), which is electrically connected in parallel to the first electrical connection, characterized in that the switching mechanism housing (16) is integrally formed in one piece and / or the first base body (36) forms at least part of the second housing side (26) of the switching mechanism housing (16), wherein said part of the second housing side (26) forms a freely accessible outside (60) of the switch (100).

2. The temperature-dependent switch according to claim 1, wherein the PTC component (46) is arranged in the switch housing (12).

3. The temperature-dependent switch according to claim 1 or 2, wherein the switch housing (12) comprises an electrically conductive second base body (38), which is connected to the first base body (36) via the PTC component (46), wherein the second base body (38) surrounds the first housing side (24) and the housing circumferential side (28) of the switching mechanism housing (16).

4. The temperature-dependent switch according to any one of the preceding claims, wherein the switching mechanism housing (16) lies with its first housing side (24) on the PTC component (46).

5. The temperature-dependent switch according to any one of the preceding claims, wherein said part of the second housing side (26) of the switching mechanism housing (16) which forms the freely accessible outside (60) of the switch (100) comprises an outwardly arched, domed or pot-shaped portion (62).

6. The temperature-dependent switch according to claim 3, comprising an insulator (48), which is arranged between the first base body (36) and the second base body (38) and abuts the first base body (36) and the second base body (38).

7. The temperature-dependent switch according to claim 6, wherein the insulator (48) comprises an annular body (50), which lies with its inside (52) on the housing circumferential side (28) of the switching mechanism housing (16) and lies with its outside (54) on an inner circumferential surface of the switch housing (12).

8. The temperature-dependent switch according to claim 7, wherein the annular body (50) lies with its underside on the PTC component (46).

9. The temperature-dependent switch according to any one of the preceding claims, wherein a diameter of the opening (30) is smaller than a diameter, measured parallel thereto, of the bimetallic snap-action disc (18).

10. The temperature-dependent switch according to any one of the preceding claims, wherein the bimetallic snap-action disc (18) is configured to snap over from a geometrically stable low-temperature configuration into a geometrically stable high-temperature configuration when the response temperature is exceeded, and wherein the bimetallic snap-action disc (18) is supported in its high-temperature configuration on a supporting surface (68), which is arranged on the first housing side (24) of the switching mechanism housing (16) and is formed on the first base body (36), and, in the process, keeps the movable contact part (22) at a distance from the stationary contact (32).

11. The temperature-dependent switch according to any one of the preceding claims, wherein the switching mechanism unit (14) further comprises a spring snap-action disc (20) which is coupled to the movable contact part (22) and is supported in the low-temperature position of the switch (100) on an internal surface (64) arranged on the second housing side (26) in the interior of the switching mechanism housing (16).

12. The temperature-dependent switch according to any one of the preceding claims, wherein an intermediate space extending circumferentially between the switching mechanism housing (16) and the switch housing (12) is filled with insulating compound (44).

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