EP3796360B1 - Temperature-dependent switch - Google Patents

Description

The present invention relates to a temperature-dependent switch with a housing which has a cover part with an underside and an upper side and an electrically conductive lower part, with a first outer contact surface arranged on the upper side of the cover part and a second outer contact surface provided on the outside of the housing, and with a temperature-dependent switching mechanism arranged in the housing which, depending on its temperature, establishes or opens an electrically conductive connection between the first and the second outer contact surface, with a circumferential cutting burr acting as a sealing means being provided on the lower part, which is either in an between the underside of the cover part and the lower part arranged insulating film or penetrates directly into the cover part.

The latter essentially depends on the design of the temperature-dependent switch. In this case, it can either be provided that the cover part is made of an electrically conductive material or of an electrically insulating material. If the cover part is made of an electrically conductive material, an insulating film, into which the cutting burr penetrates, is arranged between the cover part and the lower part. If, on the other hand, the cover part is made of an electrically insulating material, it preferably rests directly on the lower part (without the interposition of an insulating film) and the cutting burr penetrates directly into the cover part.

A generic switch according to these two fundamentally possible designs is already from the DE 10 2015 114 248 B4 known.

The known temperature-dependent switch is used in a manner known per se to monitor the temperature of a device. For this purpose, it 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.

The switch is typically connected electrically in series to the supply circuit of the protective device switched so that below the response temperature of the switch, the supply current of the device to be protected flows through the switch.

The known switch has a lower part in which an inner circumferential shoulder is provided on which the cover part rests either directly or with an insulating film in between. The cover part is held firmly on this circumferential shoulder by a raised circumferential wall of the lower part that is bent radially inward at its upper section.

The temperature-dependent switching mechanism of the DE 10 2015 114 248 B4 known switch has a spring snap-action disk which carries a movable contact part, and a bimetallic snap-action disk slipped over the movable contact part. The spring snap disk presses the movable contact part against a stationary mating contact on the inside of the cover part. With its edge, the spring snap disk is supported in the lower part of the housing, so that the electrical current flows from the lower part through the spring snap disk and the movable contact part into the stationary mating contact and from there into the cover part.

The attachment of the two external connections differs depending on the design of the temperature-dependent switch. If the cover part is made of an electrically conductive material, a first external contact surface which is arranged centrally on the cover part typically serves as the first external connection. A second external contact surface provided on the bent wall of the lower part then serves as the second external connection. However, it is also possible in this design of the switch not to arrange the second external connection on the bent edge, but instead on the side of the lower part or on the underside of the lower part.

If, on the other hand, the cover part is made of an electrically insulating material, a current transmission element in the form of a contact bridge is preferably attached to the spring snap-action disk, which is pressed by the spring snap-action disk against two stationary mating contacts provided on the underside of the cover part. In this case, not only the first but also the second outer contact surface is on the top of the Cover part arranged. The two mating contacts are connected to the two outer contact surfaces through the cover part. The current then flows from an outer contact surface via the associated counter-contact through the contact bridge into the other stationary counter-contact and from there to the other outer contact surface, so that the operating current does not flow through the spring snap-action disk itself.

This construction is chosen in particular when very high currents have to be switched that can no longer be passed through the spring snap-action disc itself without any problems.

In the two from the DE 10 2015 114 248 B4 known design variants of the switch, a bimetallic disk is provided for the temperature-dependent switching function, which rests force-free in the switching mechanism below its switching temperature.

In the context of the present invention, a bimetal part is understood to mean a multilayer, active, sheet-metal component made up of two, three or four interconnected components with different coefficients of thermal expansion. The connection of the individual layers made of metals or metal alloys are cohesive or form-fitting and are achieved, for example, by rolling.

A bimetal part of this type has a first stable geometric configuration in its low-temperature position and a second stable geometric configuration in its high-temperature position, between which it changes depending on the temperature in the manner of a hysteresis. If the temperature changes above its response temperature or below its return temperature, the bimetal part snaps into the other geometric configuration. The bimetallic part is therefore often referred to as a snap disk, with it typically having an elongated, oval or circular shape when viewed from above.

If the temperature of the bimetal part, which is typically designed as a bimetal disk, increases above the response temperature as a result of a temperature increase in the device to be protected, the bimetal disk snaps from its low-temperature configuration to its high-temperature configuration. The bimetal disc works here against the spring snap-action disk in such a way that it lifts the movable contact part from the stationary mating contact or the current transmission element from the two stationary mating contacts, so that the switch opens and the device to be protected is switched off and cannot heat up any further.

In these constructions, the bimetal disk is preferably mounted mechanically free of forces below its critical temperature, the bimetal disk also not being used to guide the current. This has the advantage that the bimetal disc has a longer mechanical service life and that the switching point, that is to say the transition temperature of the bimetal disc, does not change even after many switching cycles.

If the mechanical reliability or the stability of the critical temperature are low, the bimetallic disk can also take over the function of the spring snap disk and possibly even the current transmission element, so that the switching mechanism comprises only one bimetal disk, which then carries the movable contact part or has two contact surfaces instead of the current transmission member. In this case, the bimetal disc not only ensures the closing pressure of the switch, but also carries the current when the switch is closed.

With most temperature-dependent switches, the housing is usually protected from the entry of contaminants by a seal that is attached before or after connecting lugs or connecting cables to the external connections.

From the DE 41 39 091 A1 it is known to encapsulate the external connections with a one-component thermoset. From the DE 10 2009 039 948 A1 It is also known to encapsulate terminal lugs with an epoxy resin. It is also known to provide the switches with an impregnating varnish or protective varnish after connection lines or connection lugs have been soldered on.

In order to prevent paint, resin or other liquids from penetrating the interior of the housing, the DE 196 23 570 A1 known switch that Cover part is provided with a sealing means in the form of a circumferential bead which runs radially on the outside on the underside of the cover part. When the upper section of the circumferential wall of the lower part is bent, this circumferential bead constricts the insulating film. Although this ensures a better seal, in many cases paint still penetrates into the interior of the housing. The insulating film lying between the lower part and the cover part is pulled up laterally between the wall of the lower part and the cover part and its edge area is turned over to the top of the cover part. The stiff insulating film becomes wavy as a result of being folded over and forms rosettes which cannot be securely sealed by the upper section of the circumferential wall of the lower part pressing flat on it. There is a risk that coating varnish will penetrate the inside of the switch through the rosettes. the DE 196 23 570 A1 tries to reduce this problem with the already mentioned bead.

the DE 10 2013 102 089 B4 describes a switch as it is basically from the DE 196 23 570 A1 is known. This switch has a spacer ring between the shoulder in the lower part and the cover part, which allows a greater switching distance between the movable contact part and the stationary mating contact. To get that from the one in the DE 196 23 570 A1 In order to remedy the known leakage problem described above, in this switch the edge region of the insulating film is cut in a V-shape from the outside, whereby the waviness is greatly reduced, so that the tightness is improved.

the DE 10 2013 102 006 B4 also describes a switch of similar design. This switch has a cover part made of PTC material. Because of the lack of pressure stability of this PTC cover, the radially inwardly bent upper section of the circumferential wall of the lower part cannot adequately seal the known switch against the entry of contaminants, which is why the bent upper section of the circumferential wall opposite the top of the cover part must be sealed with silicone, which often causes problems. the DE 10 2013 102 006 B4 solves this problem in that a cover film is provided which rests only on the upper side of the PTC cover and into which the bent upper section of the circumferential wall of the lower part, lying flat on the cover film, penetrates. The face of the upper section of the circumferential Wall faces away from the cover sheet. However, the flat, upper section of the circumferential wall of the lower part often does not provide the desired seal.

A cover film and an insulating film can also be provided on a switch, such as, for example, the DE 10 2013 102 089 B4 shows. On the top of the cover part of this switch there is an insulating cover film, for example made of Nomex®, which extends with its edge radially outward as far as the insulating film, which for example consists of Kapton®. Nomex® and Kapton® are made of aramid paper or aromatic polyimides.

In the known switches, despite the various sealing measures, tightness problems occur again and again, among other things due to the fact that no permanent seal can be achieved with the relatively stiff insulating film by bending the upper section of the circumferential edge of the lower part.

In the case of the one mentioned at the beginning DE 10 2015 114 248 B4 known switch, this sealing problem is solved in that a circumferentially self-contained cutting burr is formed in one piece with the shoulder in the lower part, this cutting burr penetrating from below into the insulating film (if present) or from below directly into the cover part. The penetration of this self-contained cutting ridge into the insulating film or the cover part results in a secure seal between the lower part and the cover part.

The cutting burr is created when the lower part is manufactured. It is formed in one piece with the shoulder in the lower part. In this case, the lower part is mostly produced as a turned part, so that the cutting burr is a turning groove that is also produced when the lower part is turned.

In order to ensure sufficient tightness, however, this turning groove must be made very precisely. A production of the lower part including this precisely to be produced turning grooves is very complex and thus increases the production costs.

Against this background, the present invention is based on the object of eliminating or at least reducing the sealing problems mentioned above in the known switch in a structurally simple and inexpensive manner.

Based on the switch mentioned at the outset, this object is achieved according to the invention in that the cutting burr is arranged on a sealing ring, which is connected to the lower part in a non-positive, positive and / or cohesive manner.

As with the one from the DE 10 2015 114 248 B4 Known switch, the cutting burr penetrates from below either into the insulating film, if such is present between the lower part and the cover part, or it penetrates directly into the cover part, which is then made of insulating material. The cutting burr serves as a mechanical barrier that creates a type of seal that acts by penetrating the cutting burr into the insulating film or the cover part lying above it. The sealing effect is thus achieved by a construction element that represents a mechanical obstacle to the ingress of contamination, that is, it reliably retains both particles and fluids. Creeping paths for liquids, which could otherwise arise between the cover part and the lower part, are almost completely avoided, so that when the switch is soaked with protective varnish, this protective varnish or other impurities cannot crawl into the interior of the switch.

The cutting burr also ensures that no liquid can get into the interior of the switch when it becomes resinous. Even when soldering connection lines to the switch, the penetration of the cutting burr into the insulating film or the cover part prevents solder or corresponding liquids from getting into the interior of the switch.

The main advantage of the embodiment according to the invention over that from the DE 10 2015 144 248 B4 known switch consists in that the cutting burr is arranged according to the invention on a sealing ring which is connected to the lower part in a non-positive, positive and / or cohesive manner. According to the invention, the cutting burr is therefore not integrally connected to the lower part of the switch, as shown in the DE 10 2015 114 248 B4 is known, but arranged on an extra sealing ring.

This sealing ring together with the cutting burr formed thereon can be easily inserted into the lower part during manufacture of the switch and connected to it, for example, by clamping, welding, soldering or crimping.

The cutting burr itself can be formed on the sealing ring much more easily in terms of manufacturing than on the lower part of the switch, since the sealing ring already has a very simple geometric shape on which a cutting burr can be attached without any problems.

Since the cutting burr is not formed in one piece on the lower part, the lower part can also be produced in a significantly simpler and more cost-effective manner. The lower part can be produced, for example, as a stamped part. In principle, the sealing ring together with the cutting burr arranged on it can also be produced as a stamped part.

This results in a significant reduction in the production costs of the switch, although it still has the same sealing properties as that from FIG DE 10 2015 114 248 B4 known switches.

The object of the invention is therefore completely achieved.

The cutting burr is preferably designed to be closed on the circumference. This results in an even better sealing effect, because a self-contained seal in the form of an annular barrier is created when the new switch is installed.

If an insulating film is arranged between the lower part and the cover part, the cover part can be made of electrically conductive material. The insulating film then runs inside the switch between the lower part and the cover part and laterally between the circumferential wall of the lower part and the cover part and is with its edge area turned over on the top of the lid part. In this way, the cover part and the lower part are electrically isolated from one another.

If the cover part consists of an electrically insulating material, the insulating film per se is not required, but it can nevertheless be provided in order to ensure a reliable sealing of the switch in the manner described above. The insulating film then only has to be provided between the underside of the cover part and the lower part and does not have to extend onto the upper side of the cover part. It can therefore be designed like an insulating ring that rests on the lower part. In principle, however, the insulating film can then also be dispensed with entirely. The cover part made of electrically insulating material can also rest with its underside directly on the lower part, so that in this case the cutting burr protrudes directly into the cover part from the underside.

According to one embodiment, the cutting burr provided on the sealing ring protrudes from an upper side of the sealing ring with a height which is between 10 μm and 50 μm, preferably 20 μm to 30 μm.

This height has proven itself, because the insulating film usually used has a thickness in the range of less than 100 µm, so that the cutting burr penetrates into the insulating film up to a maximum of half this thickness, whereby the electrical insulating effect of the insulating film is maintained.

At its base, the cutting burr preferably has a width which is between 70% and 120% of the height of the cutting burr. In general, it is preferred that the cutting burr essentially has the shape of a triangle, particularly preferably the shape of an isosceles triangle, in cross section.

According to a further embodiment, the sealing ring on which the cutting burr is formed is glued, soldered or welded to the lower part of the switch.

In this case, the sealing ring, together with the cutting burr arranged thereon, is inserted into the lower part and subsequently connected to it in a materially bonded manner by gluing, soldering or welding. This ensures a stable and tight connection between the sealing ring and the lower part of the housing. The production is therefore very easy.

Furthermore, it is preferred that the lower part has a circumferential wall, the upper section of which overlaps the cover part, and that a circumferential shoulder is provided in the lower part on which the cover part rests directly or indirectly, the upper section of the lower part on the cover part the circumferential shoulder presses.

This design variant is already from the DE 10 2015 144 248 B4 known. It has the advantage that no further components are required for fastening the cover part to the lower part. The cover part is simply attached to the lower part by the upper part of the lower part which is bent over onto the cover part. The bent upper edge of the lower part presses the cover part onto the circumferential shoulder provided in the lower part, on which the cover part rests either directly or indirectly (for example with the interposition of the insulating film).

The sealing ring with the cutting burr arranged thereon is preferably arranged in the area of the circumferential shoulder provided in the lower part. It can for example be arranged on, next to or in this shoulder.

According to one embodiment, it is provided that a circumferential recess is provided in the circumferential shoulder, into which the sealing ring is crimped or pressed.

This depression is preferably designed as a groove-shaped depression in the circumferential shoulder. The sealing ring together with the cutting burr arranged on it is inserted into this recess and fastened in it by flanging. It is also possible to provide a press fit so that the sealing ring is pressed into the recess. It arises a form-fitting and / or force-fitting connection by means of which the sealing ring including the cutting burr is held captive on the lower part of the switch housing.

Of course, it is also possible not only to connect the sealing ring to the circumferential shoulder in a form-fitting or non-positive manner, but also to provide an integral connection between the two components, for example by means of gluing, soldering or welding.

The sealing ring is preferably designed as an inlay or insert that is inserted into the lower part and connected to it in a form-fitting, force-fitting and / or material fit.

According to a further embodiment, the lower part, in particular the circumferential shoulder of the lower part, is made of a material that has a higher hardness than a material from which the sealing ring is made.

This has the advantage that the sealing ring together with the cutting burr arranged on it can be attached more easily to the lower part by means of a form-fitting connection. In particular, the crimping or pressing of the sealing ring into the lower part of the switch is simplified as a result.

According to a further embodiment, it is provided that a circumferential notch is provided in the lower part, and that the sealing ring has an annular bead or feather key on its underside facing the circumferential notch, which is fitted, pressed or crimped into the circumferential notch.

Such a positive connection is similar to a tongue and groove connection. This guarantees stable retention of the sealing ring on the lower part. In addition to this type of groove and feather key connection, the sealing ring can be connected to the lower part in a materially bonded manner in order to further increase the mechanical stability of the connection.

The circumferential notch is preferably made in the circumferential shoulder in the lower part.

It is also preferred if the insulating film is made of polyimide, preferably of an aromatic polyimide. Such protective films are known from the prior art. They are sold, for example, under the trade name Kapton®. An insulating film made of this material is characterized by the fact that it is "pullable", that is to say that it stretches a little when the cover part is inserted into the lower part, and that it can nevertheless be easily folded around the face of the cover part on its upper side required dielectric strength is achieved.

It is preferred that the second outer contact surface is arranged on the upper section of the circumferential wall, in which case the switching mechanism preferably carries a movable contact part that interacts with a stationary mating contact that is arranged on the underside of the cover part and with one on the top arranged first outer contact surface cooperates.

Alternatively, it is preferred if the second outer contact surface is arranged on the top of the cover part, the switching mechanism then preferably carrying a current transmission element which interacts with two stationary counter-contacts that are arranged on the underside of the cover part and with the two arranged on the top cooperate outer contact surfaces. The advantage here is that the switch can also be designed to switch and conduct very high currents, for which purpose the two stationary mating contacts interact with a current transmission element in the form of a contact bridge or a contact plate, so that the operating current of the device to be protected does not flow through the spring Snap disk or even the bimetal snap disk, but only flows through the current transmission element.

Regardless of the design variant of the switch, it is preferred that the switching mechanism has a bimetal part. The bimetal part can be a round, preferably circular, bimetal snap disk, it also being possible to use an elongated bimetal spring clamped on one side as the bimetal part. With simple switches, the bimetal part can also be used to conduct electricity.

Furthermore, it is preferred that the switching mechanism additionally has a spring snap-action disk. This spring snap disk can, for example, carry the movable contact part and lead the current through the closed switch and the closed state ensure the contact pressure. In this way, the bimetallic part is relieved of both current conduction and mechanical stress when it is closed.

If the switching mechanism has a current transmission element that interacts with two stationary mating contacts, either only a bimetal part can also be provided, which then provides the closing pressure and takes over the opening function, or a spring part can also be provided which applies the closing force so that the bimetal part is only mechanically loaded when it opens the switch.

The present invention is particularly suitable for at least approximately round temperature-dependent switches, which are round, circular or oval when viewed from above on the lower part or cover part Lower part can be realized on which the cover part rests. The sealing ring is preferably adapted to the shape of the switch. It is therefore preferably round, circular or oval when viewed from above.

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

Fig. 1

eine schematische Schnittansicht eines ersten Ausführungsbeispiels des erfindungsgemäßen Schalters in einer ersten Schaltstellung;

Fig. 2

eine schematische Schnittansicht des in Fig. 1 gezeigten ersten Ausführungsbeispiels des erfindungsgemäßen Schalters in einer zweiten Schaltstellung;

Fig. 3

eine schematische Schnittansicht im Detail einer ersten Verbindungsvariante eines Dichtrings mit einem Unterteil des Schalters;

Fig. 4

eine schematische Schnittansicht im Detail einer zweiten Verbindungsvariante des Dichtrings mit dem Unterteil des Schalters;

Fig. 5

eine schematische Schnittansicht im Detail einer dritten Verbindungsvariante des Dichtrings mit dem Unterteil des Schalters;

Fig. 6

eine schematische Schnittansicht eines zweiten Ausführungsbeispiels des erfindungsgemäßen Schalters in einer ersten Schaltstellung; und

Fig. 7

eine schematische Schnittansicht des in Fig. 6 gezeigten zweiten Ausführungsbeispiels des erfindungsgemäßen Schalters in einer zweiten Schaltstellung.

Exemplary embodiments of the invention are shown in the drawing and are explained in more detail in the description below. Show it:

Fig. 1

a schematic sectional view of a first embodiment of the switch according to the invention in a first switch position;

Fig. 2

a schematic sectional view of the in Fig. 1 shown first embodiment of the switch according to the invention in a second switch position;

Fig. 3

a schematic sectional view in detail of a first connection variant of a sealing ring with a lower part of the switch;

Fig. 4

a schematic sectional view in detail of a second connection variant of the sealing ring with the lower part of the switch;

Fig. 5

a schematic sectional view in detail of a third connection variant of the sealing ring with the lower part of the switch;

Fig. 6

a schematic sectional view of a second embodiment of the switch according to the invention in a first switch position; and

Fig. 7

a schematic sectional view of the in Fig. 6 shown second embodiment of the switch according to the invention in a second switch position.

In Fig. 1 is shown in a schematic, sectional side view of a switch 10, which is rotationally symmetrical in plan view and preferably has a circular shape.

The switch 10 has a housing 12 in which a temperature-dependent switching mechanism 14 is arranged. The housing 12 comprises a pot-like lower part 16 and a cover part 18 which is held on the lower part 16 by a bent or flanged edge 20.

In the in Fig. 1 The first embodiment shown is both the lower part 16 and the cover part 18 made of an electrically conductive material, preferably made of metal. The cover part 18 rests on a shoulder 24 encircling the interior of the lower part 16 with an insulating film 22 in between. The upper edge 20 of the lower part 16 is bent radially inward in such a way that it has the insulating film 22 lying between the cover part 18 presses on the circumferential shoulder 24 when it is opposite the in Fig. 1 The situation shown schematically is bent even further towards the top of the cover part 18.

The insulating film 22 ensures electrical insulation of the cover part 18 from the lower part 16. In addition, the insulating film 22 also provides a mechanical seal that prevents liquids or contaminants from entering the interior of the housing from the outside.

The insulating film 22 runs inside the housing 12 parallel to the cover part 18 along the underside 25 thereof. From there, it extends laterally between the cover part 18 and the circumferential shoulder 24 up to over the top 23 of the cover part 18 out of the housing 12 . The bent or beaded upper edge 20 of the lower part 16 lies flat on the upper edge region of the insulating film 22 and presses it in the direction of the upper side 23 of the cover part 18.

A further insulating cover 26 is provided on the upper side 23 of the cover part 18 and extends radially outward as far as the insulating film 22.

The switching mechanism 14 has a temperature-independent spring part 28 designed as a spring washer and a temperature-dependent snap part 30 designed as a bimetal snap disk.

The spring part 28 is preferably designed as a bistable spring washer. The spring washer 28 accordingly has two temperature-independent stable geometric configurations. In Fig. 1 its first geometric configuration is shown.

The temperature-dependent bimetal snap disk 30 is preferably designed as a bistable snap disk. The snap disk 30 has two temperature-dependent configurations, a high-temperature geometrical configuration and a low-temperature geometrical configuration. In the in Fig. 1 The first switching position of the switching mechanism 14 shown is the snap disk 30 in its low-temperature configuration.

The spring washer 28 rests with its edge 32 on an inner bottom surface 34 of the lower part 16. The inner bottom surface 34 is essentially concave and at the point where the edge 32 of the spring washer 28 in the FIG Fig. 1 first switching position shown rests, slightly increased compared to the central area of the inner bottom surface 34. The snap disk 30 lies with its edge 36 in its in Fig. 1 shown low-temperature configuration on the spring washer 28.

With its center 38, the spring washer 28 is fixed to a movable contact member 40 of the switching mechanism 14. The center 42 of the bimetallic snap disk 30 is also fixed on this contact member 40. In this way, the temperature-dependent switching mechanism 14 is a captive unit of contact element 40, spring washer 28 and bimetallic snap disk 30.

The movable contact member 40 has a movable contact part 44 on its upper side. The movable contact part 44 works together with a stationary mating contact 46, which is arranged on the underside 25 of the cover part 18. The top 23 of the cover part 18, which is electrically conductively connected to the stationary mating contact 46, serves as the first outer contact surface 48 in this exemplary embodiment. The outside of the lower part 16 serves as a second outer contact surface 50 16 serve as a second outer contact surface 50.

In the in Fig. 1 The closed switching position of the switch 10 shown in the figure, the movable contact part 44 is pressed by the spring washer 28 against the stationary mating contact 46. Because the edge 32 of the electrically conductive spring washer 28 is in connection with the lower part 16, an electrically conductive connection between the two outer contact surfaces 48, 50 is established.

If the temperature inside the switch 10 now increases above the switching temperature of the bimetal snap disk 30, it snaps from its in Fig. 1 convex low-temperature configuration shown in their in Fig. 2 Concave high temperature configuration shown around.

In the in Fig. 2 The high-temperature configuration shown, the bimetal snap disk 30 is supported with its edge 36 on the underside of the insulating film 22 and presses the movable contact member 40 with its center 42 downwards. As a result, the movable contact part 44 is lifted off the stationary mating contact 46. The spring washer 28 snaps from its in Fig. 1 shown, first geometrically stable configuration in its in Fig. 2 shown, second geometrically stable configuration.

Since the switch 10 is thus now open and the power supply to the device to be protected is interrupted, the device to be protected and thus also the switch 10 can cool down again. When the temperature inside the switch 10 then cools down again to a temperature below the switch-back temperature of the bimetal snap-action disk 30, it snaps out of its position again Fig. 2 high temperature configuration shown back in its in Fig. 1 Low temperature configuration shown. The spring washer 28 also snaps back into its first geometrically stable configuration and brings the movable contact part 44 back into contact with the stationary mating contact 46. The switch 10 or the circuit is then closed again.

In order to improve the sealing of the interior of the housing, a sealing ring 52 is arranged in the area of the circumferential shoulder 24, on the upper side of which a cutting burr 54 is formed. The cutting burr 54 is preferably designed as a circumferentially closed cutting burr which is integrally connected to the sealing ring 52.

Sealing ring 52 together with the cutting ridge 54 arranged thereon form a type of inlay which is inserted into the lower part 16 in the area of the circumferential shoulder 24.

The sealing ring 52 together with the cutting burr arranged thereon is preferably produced as a stamped part. This stamped part is non-positive, positive and / or cohesive in the area the circumferential shoulder 24 (for example on, next to, below or in the circumferential shoulder 24) is connected to the lower part 16.

The lower part 16 and the sealing ring 52 can thus be produced as two separate components which are subsequently connected to one another. This enables a very simple production of both components, since both the lower part 16 and the sealing ring 52 with the cutting burr 54 arranged thereon can be produced as inexpensive stamped parts.

In Fig. 3-5 three different exemplary embodiments are shown of how the sealing ring 52 with the cutting burr 54 arranged thereon attaches to the lower part. 16 can be attached.

According to the in Fig. 3 The first exemplary embodiment shown, the sealing ring 52 is firmly bonded to the lower part 16. For example, the sealing ring 52 is glued, soldered or welded to the lower part 16 in the area of the shoulder 24. In addition, the sealing ring 52 can be fitted into the lower part 16 in a type of press fit. This additionally stabilizes the connection between the sealing ring 52 and the lower part 16. In this regard, it is particularly preferred that the circumferential shoulder 24 or the lower part 16 is made of a material that has a higher hardness than the material from which the sealing ring 52 is made.

Fig. 4 shows a further embodiment in which the sealing ring 52 is arranged in a circumferential recess 56 which is introduced into the shoulder 24 of the lower part 16. For example, the circumferential recess 56 can be a groove-shaped recess which is introduced into the shoulder 24 from above and into which the sealing ring 52 can be pressed or crimped.

In the in Fig. 5 In the third embodiment shown, a circumferential notch 58 is provided in the lower part 16, into which a bead 62 arranged on the underside 60 of the sealing ring is fitted, pressed or crimped. The notch 58 has in the Fig. 5 embodiment shown has a substantially V-shaped cross section. The bead 62, however, has a substantially semicircular or U-shaped Cross-section. It goes without saying, however, that other cross-sectional shapes can also be provided for the notch 58 and the bead 62. The cross-sectional shapes of the notch 58 and the bead 62 can also be configured to be equivalent to one another. In this case, however, it is preferred that the bead 62 is oversized with respect to the notch 58.

All three in Fig. 3-5 The exemplary embodiments shown have in common that the cutting burr 54 provided on the upper side of the sealing ring 52 cuts into the insulating film 22. As a result, the cutting burr 54 forms a mechanical barrier which prevents liquids or other contaminants from getting between the underside of the insulating film 22 and the lower part 16 into the interior of the housing 12.

The cutting ridge 54 is preferably at a height h (see Fig. 3 ) above the shoulder 24, which is between 10 µm and 50 µm. The insulating film 22 typically has a thickness in the region of 100 μm. The cutting burr 54 thus cuts into the insulating film 22 to a maximum of 50% of its thickness. The electrically insulating properties of the insulating film 22 are therefore retained.

Fig. 6 and 7th show a second exemplary embodiment of the switch 10 according to the invention. Fig. 6 shows the closed switch position of switch 10. Fig. 7 shows the open switch position of switch 10.

The switch 10 according to the in Fig. 6 and 7th The second embodiment shown differs from that in FIG Fig. 1 and 2 The first exemplary embodiment shown essentially by the structure of the housing 12 'and by the structure of the switching mechanism 14'.

The lower part 16 'is in turn made of electrically conductive material. In contrast, the flat cover part 18 'is made of an electrically insulating material here. Accordingly, no insulating film 22 is necessary here, which has to be inserted between the lower part 16 'and the cover part 18'. In principle, however, the in Fig. 6 and 7th an insulating film 22 may be provided as shown in FIG Fig. 1 and 2 is shown. However, this would then only serve to mechanically seal the interior of the housing and not to electrically isolate the cover part 18 'from the lower part 16'.

Here, too, a sealing ring 52 'is arranged between the cover part 18' and the lower part 16 ', on the upper side of which a cutting burr 54' is arranged. In this exemplary embodiment, the cutting burr 54 'penetrates directly into the underside 25 of the cover part 18'. As before, it serves as a mechanical barrier that is intended to prevent contaminants from penetrating into the interior of the switch 10. The cutting burr 54 'is accordingly preferably designed here as a circumferential, closed cutting burr.

The sealing ring 52 'is inserted into the lower part 16'. It rests with its underside on a shoulder 64 encircling the interior of the lower part 16 ′. The sealing ring 52 'thus also acts at the same time as a spacer ring which keeps the upper part 18' at a distance from the lower part 16 '.

The sealing ring 52 'is similar to that in FIG Fig. 1 and 2 shown first embodiment of the switch 10 according to the invention, non-positively, positively and / or cohesively connected to the lower part 16 '. As already mentioned above, the sealing ring 52 'can be glued, welded or soldered to the lower part 16', for example. The sealing ring 52 'can also be connected to the lower part 16' in a form-fitting and / or force-fitting manner by crimping. Furthermore, it is possible to clamp the sealing ring 52 'by means of a press fit in the lower part 16'. In the Fig. 3-5 The fastening variants shown also apply equivalently to the fastening of the sealing ring 52 'to the lower part 16'.

The in Fig. 6 and 7th The second embodiment of the switch 10 shown, the two outer contact surfaces 48 ', 50' are arranged on the top 23 of the cover part 18 '. These two outer contact surfaces 48 ', 50' are formed on the upper side of two rivets which are arranged at a distance from one another and which extend through the cover part 18 '. On the underside of each rivet there is a respective stationary contact 66, 68 which protrudes downward from the underside 25 of the cover part 18 '.

The switching mechanism 14 'is also designed somewhat differently here than before. The movable contact member 40 'comprises a current transmission member 70, which is designed as a contact plate, the upper side of which is coated in an electrically conductive manner, so that in the case of FIG Fig. 6 system shown on the stationary contacts 66, 68 ensures an electrically conductive connection between the two contacts 66, 68.

The current transmission element 70 is connected to the spring washer 28 and the bimetallic snap disk 30 via a rivet 72, which is also to be regarded as part of the contact element 40 ′.

Similar to before, the bimetal snap disk 30 snaps out of the in Fig. 6 low-temperature configuration shown in their in Fig. 7 The high-temperature configuration shown in FIG Fig. 6 first geometrical position shown in its in Fig. 7 second geometric position shown snaps. The current transmission member 70 is lifted from the two stationary contacts 66, 68 so that the circuit is interrupted.

The main advantage of the in Fig. 6 and 7th The switch structure shown in the figure can be seen in the fact that, in contrast to the one in Fig. 1-2 shown first embodiment of the switch 10 neither through the spring washer 28 nor through the bimetal snap disk 30 in the closed state of the switch 10, a current flows. This only flows from the first outer contact surface 48 'via the first stationary contact 66, the current transmission member 70 and the second stationary contact 68 to the second outer contact surface 50'.

Claims (15)

1. Temperature-dependent switch (10) having a housing (12) which comprises a cover part (18) with a lower side (25) and an upper side (23) as well as an electrically conductive lower part (16), wherein an insulating foil (22) is arranged between the lower side (25) of the cover part (18) and the lower part (16), having a first external contact surface (48) arranged on the upper side (23) of the cover part (18), a second external contact surface (50) provided externally on the housing (12), and having a temperature-dependent switching mechanism (14) which is arranged in the housing (12) and which, depending on its temperature, establishes or opens an electrically conductive connection between the first and the second external contact surfaces (48, 50), wherein a circumferential cutting burr (54) acting as a sealing means is provided, which penetrates into the insulating foil (22),
   characterized in that the cutting burr (54) is arranged on a sealing ring (52) which is connected to the lower part (16) in a non-positive, positive and/or firmly bonded manner.
2. Temperature-dependent switch (10') having a housing (12'), which comprises a cover part (18') made of an electrically insulating material with an lower side (25) and an upper side (23) as well as an electrically conductive lower part (16'), having a first external contact surface (48') arranged on the upper side (23) of the cover part (18') and a second external contact surface (50') spaced therefrom, which is also arranged on the upper side (23) of the cover part (18'), and having a temperature-dependent switching mechanism (14') which is arranged in the housing (12') and which, depending on its temperature, establishes or opens an electrically conductive connection between the first and the second external contact surfaces (48'; 50'), wherein a circumferential cutting burr (54') acting as a sealing means is provided, which penetrates into the cover part (18'), characterized in that the cutting burr (54') is arranged on a sealing ring (52') which is connected to the lower part (16') in a non-positive, positive and/or firmly bonded manner.
3. The switch according to claim 1 or 2, characterized in that the cutting burr (54, 54') is circumferentially closed in itself.
4. The switch according to one of claims 1 to 3, characterized in that the cutting burr (54, 54') provided on the sealing ring (52, 52') protrudes from an upper side of the sealing ring (52, 52') with a height that lies between 10 µm and 50 µm, preferably between 20 µm and 30 µm.
5. The switch according to one of claims 1 to 4, characterized in that the sealing ring (52, 52') including the cutting burr (54, 54') is manufactured as a turned part or as a punched part.
6. The switch according to one of claims 1 to 5, characterized in that the sealing ring (52, 52') is glued, soldered or welded to the lower part (16, 16').
7. The switch according to one of claims 1 to 6, characterized in that the lower part (16, 16') comprises a circumferential wall, the upper section (20) of which overlaps the cover part (18, 18').
8. The switch according to claim 7, characterized in that a circumferential shoulder (24, 64) is provided in the lower part (16, 16'), wherein the cover part (18, 18') rests directly or indirectly on the circumferential shoulder (24, 64), wherein the upper section (20) of the lower part (16, 16') presses the cover part (18, 18') onto the circumferential shoulder (24, 64).
9. The switch according to claim 8, characterized in that a circumferential recess (56) is provided in the circumferential shoulder (24, 64), into which circumferential recess (56) the sealing ring (52, 52') is flanged or pressed.
10. The switch according to one of claims 1 to 9, characterized in that the lower part (16, 16') consists of a material which has a higher hardness than a material of which the sealing ring (52, 52') consists.
11. The switch according to one of claims 1 to 10, characterized in that a circumferential notch (58) is provided in the lower part (16, 16'), and in that the sealing ring (52, 52') comprises on its lower side facing the circumferential notch (58) an annular bead or feather key (62) which is fitted, pressed or flanged into the circumferential notch (58).
12. The switch according to one of claims 1 to 11, characterized in that the switching mechanism (14, 14') carries a movable contact part (44, 44') that interacts with a stationary counter-contact (46, 66, 68) arranged on the lower side (25) of the cover part (18, 18') and interacting with the first external contact surface (48, 48', 50') arranged on the upper side (23).
13. The switch according to claim 2, characterized in that the switching mechanism (14) carries a current transfer member (70) which interacts with two stationary counter-contacts (66, 68) arranged on the lower side (25) of the cover part (18') and interacting with the two external contact surfaces (48', 50') arranged on the upper side (23).
14. The switch according to one of claims 1 to 13, characterized in that the switching mechanism (14, 14') comprises a bimetal part (30).
15. The switch according to one of claims 1 to 14, characterized in that the switching mechanism (14, 14') comprises a snap-action spring disc (28).

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