EP3410457A1 - Temperature-dependent switch with a spacer ring - Google Patents

Abstract

A temperature-dependent switch (10 ') is provided with a housing having a cover part (44) with a bottom (23) and an upper side (21) and an electrically conductive lower part (14) with a peripheral shoulder (17) and a peripheral wall (19), whose upper portion (20) engages over the cover part (44). The switch (10 ') has at least one on the upper side (21) of the cover part (4) arranged first outer contact surface (45), at least one externally provided on the housing second outer contact surface (46), wherein the cover part (44) cross upper portion (20) of the peripheral wall (19) of the lower part (14), the cover part (44) on the circumferential shoulder (17) presses, and in the housing (12) arranged temperature-dependent switching mechanism, which in dependence on its temperature electrically conductive connection between the first and the second outer contact surface (45, 46) establishes or opens. Between the cover part (44) and the lower part (14) a sealing means is provided, which has a circumferential cutting ridge (41) which is arranged on the shoulder (17) in the lower part (14).

Description

The present invention relates to a temperature-dependent switch having a housing which comprises a cover part with a bottom and a top side and an electrically conductive bottom part with a peripheral shoulder and a peripheral wall, the upper portion of which engages over the cover part, with at least one on top of the cover part arranged first outer contact surface, at least one externally provided on the outside of the housing second outer contact surface, wherein the lid portion cross-upper portion of the circumferential wall of the lower part presses the lid part on the peripheral shoulder, and arranged in the housing with a temperature-dependent switching mechanism, in response to its temperature establishes or opens an electrically conductive connection between the first and the second outer contact surface, wherein a sealing means is provided between the cover part and the lower part.

Such a switch is from the DE 196 23 570 A1 known.

The known temperature-dependent switch is used in a conventional manner to monitor the temperature of a device. For this purpose, for example, it is brought into thermal contact with the device to be protected via one of its outer surfaces, so that the temperature of the device to be protected influences the temperature of the derailleur.

The switch is electrically connected via the soldered to its two outer contact pads leads in series in the supply circuit of the device to be protected, 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 deep-drawn or rotated lower part, in which an inner circumferential shoulder is provided, on which a lid part rests. The lid part is held by a raised and at its upper portion radially inwardly bent circumferential wall of the base firmly on this shoulder.

Since the cover part and lower part are made of electrically conductive material, an insulating film running around the cover part is provided between them, which extends inside the switch parallel to the cover part and is pulled up laterally, so that its edge region except for the top the lid part extends. The bent upper portion of the peripheral wall of the lower part rests on the edge region of the insulating film.

The temperature-dependent switching mechanism here comprises a spring snap-action disk, which carries a movable contact part, as well as a bimetallic disk which is put over the movable contact part. The spring snap-action disc presses the movable contact part against a stationary counter contact on the inside of the cover part.

With its edge, the spring snap-action disc is supported in the lower part of the housing, so that the electric current flows from the lower part through the spring snap-action disc and the movable contact part into the stationary counter-contact and from there into the cover part.

As the first outer terminal is a first outer contact surface, which is arranged centrally on the cover part. As a second outer terminal provided on the bent wall of the lower part second outer contact surface. But it is also possible to arrange the second outer terminal not at this edge but laterally on the current-carrying housing or on the underside of the lower part.

From the DE 198 27 113 C2 It is known to attach to the spring snap-action disc a current transfer member in the form of a contact bridge, which is pressed by the spring snap disc against two provided on the underside of the cover part stationary mating contacts. In this case, the second outer contact surface is arranged on the upper side of the lid part. The two mating contacts are connected through the lid part with the two outer contact surfaces. The current then flows from an outer contact surface via the associated mating contact through the contact bridge in the other stationary mating contact and from there to the other outer contact surface, so that the spring snap disk itself is not traversed by the operating current.

This design is particularly chosen when very high currents must be switched, which can not be easily passed through the spring washer itself.

In both design variants, a bimetallic disc is provided for the temperature-dependent switching function, which rests without forces in the derailleur below their critical temperature.

In the context of the present invention, a bimetal part is understood as meaning a multilayer active sheet-metal component made of two, three or four components which are inseparably connected to one another and have different coefficients of expansion. The connection of the individual layers of metals or metal alloys are cohesively or positively and are achieved for example by rolling.

In their low-temperature position, such bimetallic parts have a first and their high-temperature position have a second stable geometric conformation, between which they change over in a temperature-dependent manner in the manner of a hysteresis. When the temperature changes beyond its response temperature or below its return temperature, the bimetal parts snap over into the other conformation. The bimetal parts are therefore often referred to as snap disks, wherein they can have an elongated, oval or circular shape in plan view.

Increases now the temperature of the bimetallic disc due to a temperature increase in the device to be protected beyond the critical temperature addition, the bimetallic disc changes its configuration and works against the spring snap-action disc, that they are the movable contact part of the stationary mating contact and the current transfer member of the two stationary mating contacts lifts, so that the switch opens and the device to be protected is turned off and can not heat up.

In these constructions, the bimetallic disc is mounted mechanically free of forces below its transition temperature, wherein the bimetallic disc is not used to guide the flow.

It is advantageous that the bimetallic discs have a long mechanical life, and that the switching point, so the critical temperature of the bimetal disc, not changed even after many switching cycles.

If lower requirements are placed on the mechanical reliability or the stability of the transition temperature, the bimetallic snap disk can also take over the function of the spring snap-action disc and possibly even the current transfer member, so that the switching mechanism comprises only one bimetallic disc, which then the movable Contact part carries or instead of the power transmission member has two contact surfaces, so that the bimetallic disc not only ensures the closing pressure of the switch, but also leads the power in the closed state of the switch.

Moreover, it is known to provide such switches with a parallel resistor which is connected in parallel with the external terminals. When the switch is open, this parallel resistor takes over part of the operating current and keeps the switch at a temperature above the transition temperature, so that the switch does not automatically close again after cooling down. Such switches are called self-holding.

It is also known to provide such switches with a series resistor, which is traversed by the operating current flowing through the switch. In this way, an ohmic heat is generated in the series resistor, which is proportional to the square of the flowing current. If the current exceeds a permissible level, the heat of the series resistor causes the rear derailleur to open.

In this way, a device to be protected is already switched off from its supply circuit when too high current flow is recorded, which has not yet led to excessive heating of the device.

Instead of a generally round bimetallic disc and a cantilever clamped on one side can be used, which carries a movable contact part or a contact bridge.

But it can also be used temperature-dependent switch, which have no contact plate as a current transfer member but a spring member which carries the two mating contact or on which the two mating contacts are formed. The spring member may be a Bimetallteil, in particular a bimetallic snap disk, which not only provides the temperature-dependent switching function, but at the same time also provides the contact pressure and the current leads when the switch is closed.

All these different design variants can be realized with the switch according to the invention, in particular, the bimetallic disc can take over the function of the spring snap-action disc.

From the DE 195 17 310 A1 is one to the from the above-mentioned DE 196 23 570 A1 Comparable constructed temperature-dependent switch known in which the cover part, however, is made of a PTC thermistor and can rest without interposition of an insulating film on an inner peripheral shoulder of the lower part to which it is pressed by the radially inwardly bent upper portion of the peripheral wall of the lower part.

In this way, the PTC thermistor cover is electrically connected in parallel to the two outer terminals, so that it gives the switch a self-holding function.

Such PTC thermistors are also referred to as PTC resistors. They are made, for example, from semiconductive, polycrystalline ceramics such as BaTiO ₃ .

Also in the case of the above mentioned DE 198 27 113 C2 known, temperature-dependent switch with contact bridge, the cover part made of PTC thermistor material, so that it also has a self-holding function. At the lid part here two rivets are arranged, the outer heads form the two outer terminals, and interact their inner heads as a stationary mating contacts with the contact bridge.

The cover member may be made of insulating material or metal in a switch of this type also, in the latter case as from the DE 196 23 570 A1 Known switch is provided around the cover part extending around insulating sheet, which extends inside the switch in parallel to the cover part and is pulled up laterally, so that its edge region extends to the top of the cover part. The radially inwardly bent upper portion of the peripheral wall of the lower part presses with the interposition of the insulating film flat on the cover part.

In the known switches, the housing is typically protected from the entry of contaminants by a seal which is applied before or even after the connection of terminal lugs or connecting leads to the external terminals.

From the DE 41 43 671 A1 It is known to overmold the outer terminals with a one-component thermosetting plastic. From the DE 10 2009 039 948 It is known to cast terminal lugs with an epoxy resin. It is also known to provide the known switch after soldering of leads or terminal lugs often with a impregnating varnish or protective varnish.

In order to prevent paint from penetrating into the interior of the housing, in the case of the aforementioned DE 196 23 570 A1 Known switch, the cover part provided with a sealing means in the form of a circumferential bead which extends radially outward on the underside of the cover part and with which it constricting the insulating film when bending the upper portion of the peripheral wall of the lower part. Although this ensures a better seal, in many cases, however, penetrates paint into the interior of the housing.

In the from the above-mentioned DE 196 23 570 A1 known and comparable switches lying between the lower part and the lid part insulating film is pulled laterally between the wall of the lower part and the lid part and turned over with its edge region on top of the lid part. The rigid insulating film is wavy by turning and forms rosettes, which can not be securely sealed by the flat pressing on them upper portion of the peripheral wall of the base. Furthermore, there is a risk that coating lacquer penetrates through the rosettes into the interior of the switch. The DE 196 23 570 A1 tries to reduce this problem by the already mentioned bead.

The DE 10 2013 102 089 B4 describes a switch, as in principle from the above-mentioned DE 196 23 570 A1 is known. This switch has between the shoulder in the lower part and the cover part on a spacer ring, which allows a larger switching distance between the movable contact part and stationary counter contact. To that of the in the DE 196 23 570 A1 In this switch, the edge region of the insulating disk is cut from the outside in a V-shaped manner, whereby the waviness is greatly reduced, so that the tightness is improved.

The DE 10 2013 102 006 B4 also describes a switch, as in principle from the above-mentioned DE 196 23 570 A1 is known. This switch is like the one from the DE 195 17 310 A1 Known switch on a cover part of PTC thermistor material. Because of the lack of pressure stability of this PTC cover, can not be effected by the radially inwardly bent upper portion of the peripheral wall of the lower part of a sufficient seal of the known switch against the entry of impurities, so the bent upper portion of the peripheral wall in the from the DE 195 17 310 A1 known switch must be sealed against the top of the lid part with silicone, which often causes problems.

The DE 10 2013 102 006 B4 solves this problem in that a cover sheet is provided, which rests only on the top of the PTC lid, and in which the bent and flat on the cover sheet auffliegende upper portion of the peripheral wall of the base penetrates. The end face of the upper portion of the peripheral wall faces away from the cover sheet. However, the flat-lying upper portion of the peripheral wall of the base often does not provide the desired seal.

At a switch and a cover sheet and an insulating film may be provided, as for example, the DE 10 2013 102 089 B4 shows. On the upper side of the cover part of this switch, an insulating covering film, for example made of Nomex®, is arranged, which extends with its edge radially outwards up to the insulating film, which consists for example of Kapton®. Nomex® and Kapton® consist of aramid paper or aromatic polyimides.

In the known switches, despite the various sealing measures, there are always problems of tightness which are based, inter alia, on the fact that the relatively stiff insulating foils can not be achieved by bending over the upper portion of the peripheral edge of the lower part of a permanent seal. In addition, the design effort is high, which is required in the known switches to achieve a good seal.

Against this background, the present invention seeks to eliminate in the known switch in a structurally simple and inexpensive way, the above-mentioned problems, at least reduce.

This object is achieved according to the invention in the switch mentioned above in that the sealing means has a circumferentially closed circumferential cutting burr, which is arranged on the shoulder in the lower part, and that the cover part consists of electrically insulating material and with its underside directly rests on the shoulder, wherein the cutting ridge protrudes from the bottom into the lid part.

This preferably circumferentially self-contained Schneidgrat penetrates during the assembly of the new switch in the lid part and thus ensures a secure seal between the inside of the lower part circumferential shoulder and the lid part. Although the cutting burr may be formed bead-shaped, but is preferably formed triangular in cross-section, with its shape is adapted to the material in that it penetrates during assembly of the new switch.

The cutting burr is generated in the manufacture of the lower part, it is integrally formed with the shoulder. The cutting burr can be produced during deep drawing, stamping or turning of the lower part.

Thus, according to the invention, a seal is produced by the cutting burr acting between the shoulder and the cover part, which does not act on an insulating film or sealing film by pressure of the bent wall, but by penetration of the cutting burr into the cover part above it, so that the cutting burr produces a mechanical barrier represents. The sealing effect is thus achieved by a structural element, which is a mechanical obstacle to penetrating pollution, so safely restrains both particles and fluids.

The sealing effect is effected in contrast to the previously pursued in the prior art strategies not primarily between an insulating film and the lid part but between the lid part and arranged on the lower cutting burr.

Namely, the inventor of the present application has recognized that the problems with the tightness of the known switches are due to the fact that the insulating sheet curls or wrinkles when bent on the top of the lid part. This leads to creepage paths for liquids not only - as previously assumed - arise between insulating film and cover part but primarily between insulating and circumferential wall of the base, so that when impregnating the known switch with protective coatings on both sides of the insulating film in the interior of the switch can crawl.

Even with respect to other electrical insulation materials, the bent wall of the lower part does not seal the upper side so well that in any case it is ensured that no liquid can get into the interior of the switch when hardening.

Even when soldering connecting lines on the top or there provided contact surface is not completely ruled out that get solder or corresponding liquids into the interior of the switch.

The fact that the cutting burr penetrates into the cover part, now results in a mechanical barrier for contamination, which acts between the cover part and the peripheral wall of the base.

If the cutting burr is circumferentially closed in itself, there is an even better sealing effect, because during the assembly of the new switch, a self-contained seal in the form of an annular barrier is formed.

Since the cover part is made of electrically insulating material, an insulating film between the lower part and the cover part per se is not required, but they can still be provided to in the manner described above for a secure seal of the Switch to worry. The insulating film must then be provided only between the underside of the lid part and the shoulder of the lower part and do not extend to the top of the lid part. It can therefore be designed as an insulating ring, which rests on the shoulder in the lower part.

Since the cover part is made of electrically insulating material, but can be completely dispensed with the insulating film. The lid part is then located with its underside directly on the shoulder, wherein the cutting ridge protrudes from the bottom into the lid part.

In this way, a very simple switch with a few components is created, which is still sealed sealed. This construction is particularly suitable when the cover part consists of a plastic material that is sufficiently soft so that the cutting burr can penetrate into the material of the cover part.

It is advantageous if the cutting burr has a cutting edge which penetrates into the material of the cover part.

It is preferred if on the underside of the cover part, a further, preferably self-contained, circumferential cutting burr is arranged.

Here it is advantageous that a further mechanical barrier between insulating film and cover part is generated.

The cutting burr and the further cutting burr are preferably at a height above the shoulder or the underside which is between 10 μm and 50 μm, preferably 20 to 30 μm.

This height has been proven, because the insulating film used in the usual way have a thickness in the range of less than 100 microns, so that the cutting burrs penetrate a maximum of half of this thickness in the insulating, so that the electrical insulation effect of the insulating film is maintained.

At their base, the cutting burrs have a width that is between 70% and 120% of the height.

In general, it is preferred if the switch comprises a covering film which rests on the upper side of the cover part, the covering film preferably extending to below the edge region of the insulating film.

When the cover film is used alone, it is used in switches in which usually the cover part is not made of metal, but consists of electrically insulating plastic or PTC material. The cover then serves for a mechanical protection of the lid part, on the other hand, but also the seal between the bent wall and the top of the lid part. This seal complements the sealing produced by the cutting ridge according to the invention between the shoulder in the lower part and the cover part or the insulating film.

If the cover film is used in addition to the insulating film, this ensures a particularly good seal of the new switch.

All these measures mean that the new switch is very well protected against the entry of contaminants into the interior of the housing.

It is further preferred if the insulating film, if present, consists of polyimide, preferably of aromatic polyimide, and the cover sheet of aramid paper.

Such protective films are known from the prior art, they are sold, for example under the trade name Kapton® or Nomex®.

Insulating films made of these materials are characterized by the fact that they are "drawable", so slightly stretch when inserting the lid part in the lower part, and that they can still be folded well around the front side of the lid part on the top, and further the required Dielectric strength is achieved.

It is preferred that the second outer contact surface is arranged on the upper side of the cover part, wherein the switching mechanism carries a current transfer member which cooperates with two stationary mating contacts, which are arranged on the underside of the cover part, and one of which in each case with one of the two the upper side arranged outer contact surfaces cooperates.

The advantage here is that the new switch can also be designed for switching and carrying very high currents, what the two stationary mating contacts interact with a current transfer member in the form of a contact bridge or a contact plate, so that the operating current of the device to be protected not by the spring -Schnappscheibe or even the bimetallic snap disk but only flows through the power transmission element.

It is preferred if the switching mechanism has a bimetal part.

The bimetallic part may be a round, preferably circular bimetal snap-action disc, wherein it is also possible to use as bimetallic an elongated, cantilevered bimetallic spring. With simple switches, this bimetal can also be used to conduct electricity.

However, it is preferred if the rear derailleur additionally has a spring snap-action disc.

This spring snap-action disc can, for example, carry the movable contact part and carry the current through the closed switch and, in the closed state, provide for the contact pressure. In this way, the bimetal is relieved of both the current flow and the mechanical load when it is closed.

If the derailleur has a current transmitting member which cooperates with two stationary mating contacts, either only one bimetal part can be provided, which then provides the closing pressure and performs the opening function, or it In addition, a spring member may be provided, which expends 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 thus round, circular or oval in the plan view of the lower part or cover part, whereby other forms of housing can use the invention when a self-contained Schneidgrat on the shoulder in the Lower part can be realized, on which the lid part rests.

Other features and advantages will become apparent from the description and the accompanying drawings.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the respective combinations indicated, but also in other combinations or in isolation, without departing from the scope of the present invention.

Fig. 1

eine schematische Schnittdarstellung in Seitenansicht eines beispielhaften temperaturabhängigen Schalters;

Fig. 2

eine schematische, vergrößerte Darstellung des Details II aus Fig. 1; und

Fig. 3

eine schematische, teilweise geschnitte Teil-Darstellung in Seitenansicht eines Ausführungsbeispiels des erfindungsgemäßen temperaturabhängigen Schalter.

Embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description. Show it:

Fig. 1

a schematic sectional view in side view of an exemplary temperature-dependent switch;

Fig. 2

a schematic, enlarged view of the detail II Fig. 1 ; and

Fig. 3

a schematic, partially cut part representation in side view of an embodiment of the temperature-dependent switch according to the invention.

In Fig. 1 is schematic, not to scale and in the lateral section a circular in plan view of temperature-dependent switch 10 is shown.

The switch 10 has a temperature-dependent switching mechanism 11, which is arranged in a housing 12, in which an insulating film 13 is arranged, which extends between a pot-like, electrically conductive lower part 14 and an electrically conductive cover part 15 which closes the lower part 14.

In the lower part 14, a circumferential lower shoulder 16 and a peripheral upper shoulder 17 are provided, on which the lid part 15 rests under interim storage of the insulating film 13, the edge region 18 extends to the top 21 of the lid part 15.

The lower part 14 has a circumferential wall 19, whose upper portion 20 engages over the lid part 15. The upper portion 20 is bent radially inwardly so that it presses on the intermediate insulating film 13, the lid member 15 on the peripheral shoulder 17 when compared to the in Fig. 1 schematically shown situation is further bent to the top 21.

Lower part 14 and cover part 15 are made in the example shown from electrically conductive material, which is why the cover 15 extending around the insulating sheet 13 is provided, which extends inside the housing 12 parallel to the cover member 15, laterally between the wall 19 and the cover part 15 is guided upward and with its edge region 18 facing upward.

The upper portion 20 of the wall 19 lies flat on the edge region 18 of the insulating film 13, and pushes it toward the top 21 of the cover part 14th

On the upper side 21 of the cover part 15, a further insulating cover 22 is provided, which extends radially outwards to the edge region 18 of the insulating film 13.

On a lower side 23 of the cover part 15, a stationary mating contact 24 is arranged, with which a movable contact part 25 carried by the switching mechanism 11 cooperates.

The rear derailleur 11 comprises a snap spring 26, which is supported with its edge 27 on the lower shoulder 16 and produces an electrically conductive connection there.

Below the spring snap-action disc 26, that is on its side facing away from the stationary counter-contact 24 side, a bimetal snap-action disc 28 is provided, which has two geometric temperature positions, the in Fig. 1 shown low-temperature position and a high-temperature position, not shown.

The bimetallic snap disk 28 lies with its edge 29 freely above a wedge-shaped, circumferential shoulder 31, which is formed on an inner bottom 32 of the lower part 14.

The lower part 14 has an outer bottom 33, is made with the thermal contact with a device to be protected.

The bimetallic snap disk 28 is supported on a peripheral shoulder 34 of the contact part 25 with its center 35.

The spring snap-action disc 26 is connected to an inner region 36 in its center permanently connected to the movable contact part 25, to which on the pin 30 which projects through the two snap discs 26 and 28, a ring 37 is pressed, on which also the shoulder 34 is formed.

The stationary electrically connected to the top 21 of the cover part 15 stationary counter-contact 24 cooperates with the movable contact part 25 and via this with the inner portion 36 of the spring snap-action disc 26, which in the in Fig. 1 shown, closed state of the switch 10 electrically connected to the shoulder 16 and via this with the lower part 14.

The top 21 serves as a first outer contact surface 38, which is indicated by a longitudinally striped surface. The outer bottom 33 of the lower part 14 may be in the switch 10th serve as the second outer contact surface, wherein it is provided in the switch 10, as the second outer contact surface 39 to use the upper portion 20 of the wall 19.

In the in Fig. 1 shown, closed switching position of the switch 10, the movable contact member 25 is pressed by the spring snap-action disc 26 against the stationary counter-contact 24. Because the electrically conductive spring snap-action disc 26 with its edge 27 is in communication with the lower part 14, an electrically conductive connection between the two outer contact surfaces 38, 39 is made.

If now the temperature inside the switch 10 increases beyond the response temperature of the bimetallic snap disk 28, then it works from the in Fig. 1 shown convex configuration in a concave configuration in which its edge 29 in Fig. 1 moved upwards so that it comes from below into contact with the edge 27 of the spring snap-action disc 26.

The bimetallic snap disk 28 presses with its center 35 on the shoulder 34 and thus lifts the movable contact part 25 from the stationary counter contact 24.

The spring snap-action disc 26 may be a bistable spring washer, which is geometrically stable even in the open position of the switch, so that the movable contact member 25 does not come back into contact with the stationary counter contact 24 even if the edge 29 of the bimetallic snap disk 28 no longer presses against the edge 27 of the spring snap-action disc 26.

If now the temperature inside the switch 10 is lowered again, then moves the edge 29 of the bimetallic snap disk 26 down and comes into abutment with the wedge-shaped shoulder 31. With its center 35, the bimetallic snap disk 26 then presses from below against the spring snap-action disc 26 and pushes them back into their other geometrically stable position, in accordance with Fig. 1 the movable contact member 25 presses against the stationary mating contact 24.

In the present example, the rear derailleur 11 in addition to the bimetallic snap disk 28, the current-acting spring snap-action disc 26, wherein in the rear derailleur 11, only the bimetallic snap disk 28 may be provided, which then aufliengen with its edge 29 on the shoulder 16 and would lead the stream.

It is also possible to arrange the bimetal snap-action disc 28 above the spring snap-action disc 26.

In Fig. 2 is the detail II of the switch 10 off Fig. 1 shown enlarged.

In the Fig. 2 the area of the switch 10 is off Fig. 1 shown enlarged, where the lid member 15 rests with the interposition of the insulating film 13 on the shoulder 17.

Radially inwardly on the shoulder 17, a cutting ridge 41 is provided, which projects perpendicularly in the direction of the cover part 15 over the shoulder 17 and has penetrated approximately one third into the insulating film 13.

On the underside 23 of the cover part 15, a further cutting ridge 42 is provided radially on the outside, which extends perpendicularly over the underside 23 in the direction of the lower part 14 and likewise projects approximately one third into the insulating film 13.

The two cutting burrs 41 and 42 are provided with an upper cutting edge 43 and have approximately triangular shape in cross section.

The two cutting burrs 41 and 42 are self-contained and radially run around, so that they each form an annular cutting ridge 41 and 42, each having an upwardly facing annular cutting edge 43.

The cutting ridge 42 has a height indicated at 51 over the underside 43, which relates to approximately 30 μm. Likewise, the cutting burr 41 has a height 52 projecting beyond the shoulder 17, which likewise relates to approximately 30 μm. The insulating film 13 has an indicated at 53 thickness, which relates to about 100 microns.

At their base on which they are integrally formed with the shoulder 17 and the bottom 23, the cutting burrs 41 and 42 have a width indicated at 54 and 55, which corresponds approximately to the height 52 and 51, respectively.

The two cutting burrs 41 and 42 each form a mechanical barrier against the possible penetration of impurities, in particular fluids, which could penetrate between the insulating film 13 and the cover part 15 and the lower part 14 in the interior of the switch.

Because the two cutting burrs 41 and 42 are circumferentially self-contained, they form a complete mechanical barrier that can not be overcome by contaminants, especially fluids.

While in Fig. 2 Both the cover part 15 and the lower part 14 are made of electrically conductive material and thus have to be electrically insulated from each other by the insulating film 13 is in Fig. 3 cut and in principle as well as cut the upper portion of a switch 10 'shown, in which the lower part 14 is again made of metal, but now a plastic existing cover part 44 is provided.

The cover member 44 is located with its bottom 23 directly on the shoulder 17 in the lower part 14, wherein on the shoulder 17 again already out Fig. 2 known cutting ridge 41 is provided, which has been cut with its upper edge 43 in the material of the cover part 14.

The lid member 44 is held by the bent upper portion 20 of the peripheral wall on the shoulder 17. During assembly of the new switch 10 ', the cutting burr 41 penetrates into the material of the cover part 44 and forms a mechanical barrier against the ingress of fluids between the cover part 44 and the lower part 14.

Also in the embodiment according to Fig. 3 the cutting burr 41 is self-contained. While the cutting ridge 41 in Fig. 3 radially rests on the inside of the shoulder 17, it can also be arranged here centrally or radially outside.

It should be noted that the shape of the cutting burrs 41 and 42 is adapted to the material in which they are to penetrate.

While at the switch 10 off Fig. 1 an outer contact surface 38 is arranged on the upper side 21 of the lid, and the other outer contact surface 39 is formed on the wall 19, the switch 10 ', from Fig. 3 two outer contact surfaces 45, 46, which are both arranged side by side on the upper side 21 of the cover part 44.

The two outer contact surfaces 45 and 46 are each connected to stationary mating contacts 47 and 48, which are arranged on the underside 23 of the cover part 44 and cooperate with a current transfer member 49 which is pressed by a spring snap-action disc 26 against the stationary mating contacts 47, 48 ,

In the case of the switch 10 ', the operating current therefore does not flow through the spring snap-action disc 26, but through the current transfer member 49.

In the in Fig. 3 shown, closed state of the switch 10 ', the spring snap-action disc 26 is supported with its edge 27 on the lower shoulder 16 in the lower part 14 and pushes the current transfer member 49 against the two stationary mating contacts 47, 48th

Claims (14)

Temperature-dependent switch having a housing (11) which has a cover part (15, 44) with a lower side (23) and an upper side (21) and an electrically conductive lower part (14) with a peripheral shoulder (17) and a peripheral wall (19 ), the upper portion (20) of which engages over the cover part (15) with at least one first outer contact surface (45) arranged on the upper side (21) of the cover part (15), at least one second outer one provided on the outer housing (12) Contact surface (46), wherein the cover part (15) cross-section upper portion (20) of the peripheral wall (19) of the lower part (14) presses the lid part (15) on the circumferential shoulder (17), and with a in the housing ( 12) arranged temperature-dependent switching mechanism (11) which establishes or opens in dependence on its temperature an electrically conductive connection between the first and the second outer contact surface (45, 46), wherein between the cover part (15) and the lower part (14) is provided with a sealing means,
characterized in that the sealing means comprises a peripheral cutting burr (41) which is arranged on the shoulder (17) in the lower part (14), and that the cover part (44) consists of electrically insulating material and with its underside (23) directly rests on the shoulder (16), wherein the cutting burr (41) protrudes from the bottom (23) forth in the lid part (15). Switch according to claim 1, characterized in that the cutting burr (41) is formed integrally with the shoulder (17). Switch according to claim 1 or 2, characterized in that the electrically insulating material is a plastic. Switch according to one of claims 1 to 3, characterized in that the cutting burr has a cutting edge, which penetrates into the cover part. Switch according to one of claims 1 to 4, characterized in that on the underside (23) of the cover part (15, 44), a further, preferably self-contained, circumferential cutting burr (42) is arranged. Switch according to claim 5, characterized in that the further cutting ridge (42) protrudes at a height above the underside (23) which is between 10 μm and 50 μm, preferably 20 to 30 μm. Switch according to one of Claims 1 to 6, characterized in that the cutting burr (41) provided on the shoulder (17) protrudes above the shoulder (17) at a height of between 10 and 50 μm, preferably between 20 and 30 μm is. Switch according to one of claims 1 to 7, characterized in that it comprises a cover film (22) which rests on the upper side (21) of the cover part (15, 44). Switch according to claim 8, characterized in that the covering film (22) consists of aramid paper. Switch according to one of claims 1 to 9, characterized in that the second outer contact surface (46) on the upper side (21) of the cover part (44) is arranged. Switch according to claim 10, characterized in that the derailleur (11) carries a current transmitting member (49) cooperating with two stationary mating contacts (47, 48) disposed on the underside (23) of the lid member (44), and of each one with one of the two at the top (21) arranged outer contact surfaces (45, 46) cooperates. Switch according to one of claims 1 to 11, characterized in that the switching mechanism (11) has a bimetal part (28). Switch according to one of claims 1 to 12, characterized in that the switching mechanism (11) has a spring snap-action disc (26). Switch according to one of claims 1 to 13, characterized in that the cutting burr (41, 42) is formed circumferentially closed in itself.

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