EP2743954B1 - Temperature-dependent switch - Google Patents

Description

The present invention relates to a temperature-dependent switch with a housing having a cover part and a lower part with a circumferential wall and a bottom, with a temperature-dependent switching mechanism disposed in the housing, which, depending on its temperature, an electrically conductive connection between two on the housing provided external connections or opens, and with a Abschirmtopf of an electrically conductive, metallic material, in which the housing is inserted with its bottom first.

Such a switch is, for example, from the US 2003/034872 A1 known.

Furthermore, one serves from the DE 103 01 803 A1 known temperature-dependent switch 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 external terminals 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 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 flanged edge of the base firmly on this shoulder.

Since the cover part and lower part are made of electrically conductive material, an insulating film is provided between them, which extends parallel to the cover part and is pulled up laterally, so that the flanged edge presses with the interposition of the insulating film on the cover part.

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

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

The first external connection is a contact surface, which is arranged centrally on the cover part. As the second outer terminal provided on the flanged edge of the base contact surface. Both external connections are here on the top of the known switch. But it is also possible to arrange the second outer terminal not on the edge, but laterally on the current-carrying housing.

On the other hand it is from the DE 198 27 113 C2 known to attach to the spring snap-action disk, a so-called contact bridge, which is pressed by the spring snap-action disc against two provided on the cover part stationary contacts. The current then flows from the one stationary contact through the contact bridge in the other stationary contact, 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 bimetal disc is provided for the temperature-dependent switching function, which rests below its critical temperature without force in the switching mechanism, wherein it is arranged geometrically between the contact part or the contact bridge and the spring snap-action disc.

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 presses with its edge against an abutment, which is usually provided on the cover part. In this case, the bimetallic disc presses with its central region against the spring snap-action disc and thus lifts the movable contact part of the stationary contact or the current transfer member of the two stationary contacts, so that the switch opens and the device to be protected is turned off and not further can heat up.

In these constructions, the bimetallic disc is mounted mechanically free of forces below its transition temperature, the bimetallic disc is also used in any case 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 demands on the mechanical reliability or the stability of the transition temperature are tolerable, the bimetallic disc can also take over the function of the spring snap-action, so that the switching mechanism comprises only a bimetallic disc, which then carries the movable contact part or the current transfer member and in the closed State of the switch also conducts the current.

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.

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.

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.

From the DE 195 17 310 A1 is one to the from the above-mentioned DE 103 01 803 A1 Comparable constructed temperature-dependent switch known in which the cover part, however, is made of a PTC thermistor and rests without interposition of an insulating film on an inner circumferential shoulder of the lower part to which it is pressed by the flanged edge of the lower part.

The first external connection is an external head of a rivet sitting centrally in the cover part, the inside head of which serves as a fixed mating contact. As a second outer terminal also serves a provided on the flanged edge of the base contact surface.

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.

When from the above mentioned DE 198 27 113 C2 known temperature-dependent switch with contact bridge, the cover part is also made of PTC thermistor, 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 stationary contacts with the contact bridge.

In the known switches, the external connections and the electrically conductive parts of the housing must still be electrically insulated after the soldering of connection lines.

As insulation and pressure protection, the known switches are therefore often used in enclosing or protective caps that serve the mechanical and / or electrical protection and often the case should also protect against the entry of impurities. Examples of this can be found for example in the DE 91 02 841 U1 , the DE 92 14 543 U1 , the DE 37 33 693 A1 and the DE 197 54 158 ,

On the other hand, it is known to mount connection caps on the switches from above, ie from the connection side, in order to ensure a defined external connection and the sealing of the housing. Examples of this can be found for example in the DE 10 2005 001 371 B4 or the DE 10 2009 030 353 B3 ,

Furthermore, it is from the DE 41 43 671 A1 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.

From the DE 24 42 397 A1 is an insulating cap for a temperature-dependent switch is known, which is designed as a cup-like surrounding housing and is pushed from below onto the housing of the temperature-dependent switch so that lead up to the switch housing soldered leads up out of the cap. The opening of the cap is then closed by a cast resin cover. The cap is made of plastic and serves for the electrical insulation of the switch, whose lower part consists of metal.

However, the use of housings or connection caps is often perceived as too expensive to construct and with regard to the thermal connection to the device to be protected as unsatisfactory.

From the DE 10 2011 016 896 B3 is a temperature-dependent switch with a bimetallic disc, an insulator body and external connections and a housing known, in which the bimetallic disc and the insulator body are used. The housing can be made of ferromagnetic steel to mechanically shield the derailleur.

From the US 4,503,414 A is a temperature-dependent switch with a melting at a predetermined temperature and thus an electrical discharge interrupting melt material known. This fusion compound is arranged together with spacers in a shielding pot.

Although the switches described so far have proven themselves in everyday use and have many advantages in terms of functionality, is currently repeatedly reported on functional problems just loosely inserted bimetallic discs and unwanted arcs when opening the switch. These effects indicate problems with the electromagnetic shielding.

Corresponding investigations in Applicant's company can be interpreted as indicating that the effects are due to changes in the electromagnetic properties of the protected equipment, which today differ from the conditions for which existing switches were originally designed.

The electromagnetic environment to which the switches are exposed during use appears to have changed in particular as a result of changed compositions of the leads, windings, winding plates, etc.

In the temperature-dependent switch from the DE 87 13 929.4 U1 For example, a planter is a metallic receptacle for the temperature dependent switch that includes an enclosed metallic housing. The receptacle is formed on a fastening part, which is provided with an external thread. The switch is inserted with the interposition of an insulating film with its bottom first in the recording. On the protruding from the receptacle cylindrical wall of the switch, a made of plastic intermediate part is inserted, which is permanently connected by a flanged edge of the receptacle with this. On the intermediate part of a likewise existing plastic lid is snapped.

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.

According to the invention this object is achieved by a switch according to the present claim 1.

Due to the additional shielding pot, which is placed only from below onto a switch of any type, according to the inventor, a structurally simple and cost-effective manner for significantly improved protection of existing switches from electromagnetic fields is provided.

It requires, in the knowledge of the inventor, neither the exchange of the usual, usually made of brass housing by a better shielding housing, such as steel, nor a switch completely surrounding the shield to an existing switch so reliable from the effects of electromagnetic fields protect it from being able to be incorporated into the windings of motors or transformers where the electromagnetic environment has changed.

Even if the cover part of the housing consists of a PTC thermistor, no additional metal cover is required in the usual dimensions of temperature-dependent switches, the shielding pot surprisingly enough as additional protection, although he does not cover the top of the switch.

The inventor has therefore just not gone the way to modify the housing itself or to insert the switch in a surrounding this from all sides shielding.

Rather, the inventor of the present application has recognized that the effect of electromagnetic fields is completely prevented or at least reduced by a shielding pot which is placed on the housing from below.

The shielding pot can be mechanically held on the housing, for example by crimping, clamping or crimping a raised edge of the Abschirmtopfes on top of the switch inserted into the Abschirmtopf. The shielding pot can also be connected by suitable resins or silicone with the top of the switch.

It is particularly advantageous that existing temperature-dependent switches can continue to be used, they do not have to be redeveloped or redesigned. It is only necessary to use the known switch in the shielding pot provided according to the invention. The shielding pot only slightly increases the geometric dimensions of the switches, so that they can continue to be installed with the shielding pot attached in such a way as without the shielding pot.

According to the invention, a shielding pot is therefore understood to mean an upwardly open planter which, owing to the physical properties of the material from which it is made, ensures a shielding of the temperature-dependent switch contained therein against electromagnetic fields. Suitable materials are in particular electrically conductive metals and metal alloys in question.

Because the insertion depth is preferably at least 10% greater than the height of the housing, it is also advantageous that the mechanical protection not only acts against loads from the side but also against forces from the top or bottom. The supernatant of Abschirmtopfes thus gives even better mechanical protection. The shielding effect is also improved by this measure.

The problem underlying the invention is completely solved in this way.

It is particularly preferred if the shielding pot is made of steel.

In particular, hot-rolled or cold-rolled deep-drawing steels which are used without coating or with a surface finish are considered as steels. The shielding pots are shaped in particular from thin sheets of the type DC.

The electrically conductive lower part of the housing existing temperature-dependent switch is usually made of brass, because brass is a material that can be processed well due to its mechanical properties. These parts are structurally demanding, they have shoulders, etc. and must be made very dimensionally stable, so that the switching function of the temperature-dependent derailleur is guaranteed.

In addition, the lower parts are responsible for the thermal connection to the device to be protected, which is why brass is preferred because of its good electrical and thus thermal conductivity.

It should also be noted that temperature-dependent switches have very small dimensions, the lower parts of the housing, for example, have a diameter of 8 to 10 mm and a total height of 4 to 6 mm. Such small parts can be made of steel, a material that gives a very good electromagnetic shielding effect, only with much greater effort and therefore significantly higher costs than brass.

Although for reasons of stability and because of the good electromagnetic shield switch with steel housing also have advantages, they have the not to be underestimated disadvantage of high production costs, especially when small dimensions nevertheless a high dimensional stability is required.

A shielding pot made of steel, however, is very simple in construction, it preferably consists of a circumferential wall which defines an insertion opening at the top and is closed at the bottom by a bottom. This simple structure can also be produced very inexpensively from steel. In addition, according to the inventor, the thicknesses of the circumferential wall and bottom can be kept very low, without the shielding effect deteriorates.

The thicknesses of wall and floor are in the range of 0.1 to 03 mm. Such thin walls and floors also ensure good thermal connection of the equipped with the shielding switch to the device to be protected.

Although according to the invention an additional shielding pot made of steel is used, the cost of such a switch equipped only slightly increased compared to the cost of the switch alone and still lower than if the switch would have a steel housing. In addition, no new switches have to be developed, tested and approved, the existing switches can still be used

The shielding pot made of steel not only protects the switch inside from electromagnetic fields, it also provides mechanical protection that the brass housing can not guarantee.

Of course, the advantages of the shielding steel, even with temperature-dependent switches are realized, whose housing is made of a different material than brass, for example, made of an insulating material or a metal sheet. Here, the pressure stability mediated by the shielding pot has a particularly advantageous effect.

An inventively equipped with a shield pot made of steel temperaturabhänggier switch, thus combines the advantages of the usual, inexpensive and dimensionally stable to manufacture housing and the steel housing, without causing the high cost associated with a steel housing.

According to the invention, the shielding pot has a peripheral wall which delimits an insertion opening at the top and is closed at the bottom by a bottom, wherein the peripheral wall is bent over with its upper edge to the top of the housing.

Here it is advantageous that the housing is mechanically held by the bent edge in the shielding pot, wherein the edge additionally provides for a mechanical protection of the cover part, which is particularly advantageous if the cover part is made of insulating material or PTC thermistor.

According to the invention, the two outer terminals are provided with connecting leads leading out of the shielding pot at the top, contact angles being fastened with their short legs to the outer terminals, and the connecting leads being fastened to their long legs. Next, the long legs are bent over the short legs.

These measures are structurally advantageous because they allow easy installation of the housing in the Abschirmtopf. After the contact angles have been fastened to the connection surfaces with the legs still standing up and the connecting leads have been fastened to the long legs, the housing, which is naturally also fitted with the temperature-dependent switching mechanism, is inserted from above into the shielding pot.

Because the connecting leads are still pointing vertically upwards, the upper edge of the peripheral wall of the shielding pot can be bent inwards in a simple manner in order to mechanically fix the housing. Only now are the long legs bent over the short legs, so that the leads lead away from the side of the switch, as it is required for most applications.

It is preferred if an electrical insulating material, preferably a silicone adhesive, one-component thermoset or a resin, in particular a composition with an epoxy resin is applied to the top, wherein the Elektroisoliermaterial covers at least the two external connections and connects the shielding pot with the housing.

In this measure, it is advantageous that the shielding pot is not or not exclusively held purely mechanically, but also / only cohesively on the housing. It is set automatically, so to speak, during the curing of the electrical insulating material on the housing. The Elektroisoliermaterial, which is preferably a silicone adhesive, one-component thermosetting plastic or a cast resin such as epoxy resin, covers at least the outer terminals of the switch and the possibly still free stripped ends of the connecting cables.

The silicone adhesive or resin also provides strain relief for the leads soldered to the outer leads or the legs of the contact angles, although a silicone adhesive does not provide the degree of stability such as an epoxy resin. Nevertheless, the electrical insulation material ensures a further improved mechanical stability and pressure compatibility of the new switch as well as improved electrical and mechanical protection of the cover part. The switch can therefore also be wrapped in a winding of a coil when the cover part consists of a PTC thermistor material.

The provided with the Abschirmtopf switch can then be subsequently introduced into a cap made of a shrink tubing to isolate the switch to the outside, as it is, for example, from the DE 197 05 153 is known.

A shielding pot for the new switch is provided with a peripheral wall which defines an insertion opening at the top and is closed at the bottom by a bottom, wherein the shielding pot consists of an electrically conductive, metallic material, preferably of steel.

This shielding pot has the features described above in connection with the new switch, wherein it can be supplied as a separate marketable part of a manufacturer of the temperature-dependent switch via a third party.

Overall, the present invention further relates to a method for final assembly of a temperature-dependent switch according to the present claim 6.

With the new method, pre-assembled switches, in which the switching mechanism has been installed in the housing, can be provided with connection lines at any time and then equipped with a shielding pot, so that they can be wrapped, for example, in windings of transformers.

Because of the electrical insulating material on top of the housing, oils or outgassing fluids used in this wrapping can not diffuse or creep into the interior of the switch, so that the switch is not only mechanically stable but also highly sealed against the environment.

The new method and the new shielding can be used in switches of any design, with changes to the switches themselves are not required.

In the following examples, three types of switches are shown by way of example, each having a pot-like lower part with a wall, the edge of which is flanged inwardly to fix the lid part on a shoulder of the lower part.

At least one external connection for a connecting line is provided in the cover part, wherein the other external connection is also provided on the cover part, if the temperature-dependent switching mechanism carries a contact plate, or if the edge itself or the bottom or a wall of the electrically conductive lower part partially as further external connection can be formed.

Such switches are often distributed by the applicant's company, they can be equipped with a cover part of PTC thermistor or with a lid part made of insulating material or with a cover part of electrically conductive material, each corresponding insulation measures are provided so that no short circuit between electrically conductive parts that affects the operation of the switch.

According to the invention, a shielding pot adapted in its geometry to the respective switch type is now placed on these existing switches if necessary, effectively protecting the pickup switch against the action of electromagnetic fields.

According to the invention, in the method in step b) two contact angles are fastened in each case with their short legs to one of the two outer terminals, and one of the two connection lines is fastened to its respective long leg.

Next, in step c), the peripheral wall is bent with its upper edge on the top of the housing.

According to the invention, the long legs are bent over onto the short legs in step c).

These measures are associated with the advantages already mentioned above. The new switch can be protected in a structurally simple and inexpensive way from the effects of electromagnetic fields.

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

Fig. 1

eine schematische Schnittdarstellung in Seitenansicht eines aus dem Stand der Technik bekannten, temperaturabhängigen Schalters.

Fig. 2

in einer Darstellung wie Fig. 1 ein weiteres Beispiel eines aus dem Stand der Technik bekannten, temperaturabhängigen Schalters, der ein Deckelteil aus Kaltleitermaterial aufweist;

Fig. 3

eine schematische Draufsicht auf den Schalter aus Fig. 1 oder Fig. 2, mit angelöteten Anschlussleitungen;

Fig. 4

in einer Darstellung wie Fig. 1 ein weiteres Beispiel eines aus dem Stand der Technik bekannten, temperaturabhängigen Schalters, der eine Kontaktbrücke und ein Deckelteil aus Kaltleitermaterial aufweist;

Fig. 5

eine schematische Draufsicht auf den Schalter aus Fig. 4, mit angelöteten Anschlussleitungen;

Fig. 6

in einer schematischen Seitenansicht den Schalter aus Fig. 4, bei dem Anschlussleitungen an auf der Oberseite angeordnete Kontaktwinkel angelötet sind, wobei unter dem Schalter schematisch und in geschnittener Seitenansicht ein Abschirmtopf gezeigt ist,

Fig. 7

den in den Abschirmtopf eingesetzten Schalter aus Fig. 6 in gegenüber Fig. 6 um 90° gedrehter Ansicht;

Fig. 8

eine Draufsicht auf den Schalter aus Fig. 3, 5 oder 7, wobei Epoxidharz die Oberseite des Schalters bedeckt; und

Fig. 9

den Schalter aus Fig. 8 in Seitenansicht.

Examples of a temperature-dependent switch are shown in the drawing and are explained in more detail in the following description. Show it:

Fig. 1

a schematic sectional view in side view of a known from the prior art, temperature-dependent switch.

Fig. 2

in a presentation like Fig. 1 a further example of a known from the prior art, temperature-dependent switch having a cover part of PTC thermistor material;

Fig. 3

a schematic plan view of the switch Fig. 1 or Fig. 2 , with soldered connecting cables;

Fig. 4

in a presentation like Fig. 1 a further example of a known from the prior art, temperature-dependent switch having a contact bridge and a cover part of PTC thermistor material;

Fig. 5

a schematic plan view of the switch Fig. 4 , with soldered connecting cables;

Fig. 6

in a schematic side view of the switch Fig. 4 in which connecting leads are soldered to contact angles arranged on the upper side, a shielding pot being shown schematically below the switch and in sectional side view,

Fig. 7

the switch inserted into the shielding pot Fig. 6 in opposite Fig. 6 rotated by 90 ° view;

Fig. 8

a plan view of the switch off Fig. 3, 5 or 7 wherein epoxy covers the top of the switch; and

Fig. 9

the switch off Fig. 8 in side view.

In Fig. 1 is schematic, not to scale and shown in side section a temperature-dependent switch 1 having a housing 2, which has a cylindrical circumferential wall 10 here, which is formed on an electrically conductive pot-like lower part 11, of a plate-like, electrically conductive cover part 12th is closed. The lid part 12 is held with the interposition of an insulating film 13 by a flanged edge 14 of the wall 10 to the lower housing part 11.

In the housing formed by the lower part 11 and cover part 12 of the switch 1, a temperature-dependent switching mechanism 15 is arranged, which comprises a Federschnappscheibe 16, which centrally carries a movable contact member 17 on which a freely inserted bimetallic disc 18 is seated.

In the context of the present invention, a bimetallic disc is understood to mean 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.

The spring snap disc 16 is supported on a bottom 19 inside of the lower part 11, while the movable contact part 17 is in contact with a fixed contact part 20 which is provided on an inner side 21 of the cover part 12.

As external terminals 22 and 23 are used in the switch Fig. 1 On the one hand, a central region of the cover part 12 and, on the other hand, a region on the flanged edge 14.

The lower part 11 is provided with a flat underside 24, via which the switch 1 is thermally coupled to a device to be protected.

The two outer terminals 22, 23 are thus adjacent to one another at an upper side 25 of the housing.

In this way, the temperature-dependent switching mechanism 15 in the in Fig. 1 low-temperature position shown an electrically conductive connection between the two outer terminals 22, 23 forth, the operating current on the fixed contact part 20, the movable contact member 17, the spring snap disk 16 and the lower part 11 flows.

Increased at the switch 1 off Fig. 1 on the thermal contact of the bottom 24 to the device to be protected, the temperature of the bimetallic disc 18 on their response temperature out, so it snaps from the in Fig. 1 shown convex position in its concave position in which it lifts the movable contact member 17 against the force of the spring washer 16 of the fixed contact member 20 and thus opens the circuit.

Fig. 2 shows a temperature-dependent switch 1 ', which is constructed similar to the switch 1 off Fig. 1 , Same constructive features are denoted by the same reference numerals as in FIG Fig. 1 Provided.

In contrast to the switch 1, in the case of the switch 1 ', the cover part 12 is not made of electrically conductive material, but of a cold conductor material 26 which acts as a self-holding resistor, so that the switch 1' is held in the open state until the supply voltage is switched off ,

In the context of the present invention, a "PTC resistor material" is understood to mean an electrically conductive ceramic material which has a positive temperature coefficient, so that its electrical resistance increases as the temperature increases. The course of the electrical resistance value over the temperature is non-linear.

Such PTC thermistors are also referred to as PTC resistors. They are made, for example, from semiconductive, polycrystalline ceramics such as BaTiO3.

The stationary contact part 20 is formed by an inner head of a rivet 27, which passes through the lid part and forms the outer terminal 22 with its outer head.

Fig. 3 shows a schematic plan view of the switches 1 and 1 ', which do not differ significantly in this view.

To the outer terminals 22, 23 is in Fig. 3 each a connecting line 27, 28 soldered to their respective stripped end 29, 31.

While the switches 1 and 1 'from the Fig. 1 and 2 are provided with a switching mechanism 15, in which the current flows through the spring snap disk 16, shows Fig. 4 a switch 1 "', in which the current is passed through a contact plate, so that this switch 1" can switch higher currents.

In Fig. 4 the temperature-dependent switch 1 "comprises a temperature-dependent switching mechanism 111 housed in the housing 2, which again has the lower side 24 and the upper side 25.

The housing 2 comprises a circumferential, here cylindrical wall 113 exhibiting lower part 114 and a this closing lid member 115 of insulating material, which is held by a flanged edge 116 of the wall 113 of the lower part 114 at this. Between the lower part 114 and the lid part 115, a ring 117 is arranged, which is supported on a shoulder 118 of the lower part 114 and there leads a spring snap-action disc 121 of the rear derailleur 111 at its edge.

The rear derailleur 111 additionally comprises, in addition to the spring snap-action disc 121, a bimetallic disc 122 which, together with the spring snap-action disc 121, is centrally penetrated by a pin-like rivet 123, by which these are mechanically connected to a current transfer member in the form of a contact plate 124. The rivet 123 has a first shoulder 125 on which the bimetallic disc 122 sits with radial and axial play, with a second shoulder 126 is provided, on which the spring snap disc 121 also sits with radial and axial play.

The bimetal disc 122 is supported with its peripheral edge inside in the lower part 114.

The already mentioned contact plate 124 has, in the direction of the cover part 115, two electrically interconnected, large-area contact surfaces 127 which cooperate with two stationary contacts 131, 132 arranged on the inner side 129 of the cover part 115, which are inner heads of contact rivets 133, 134 pass through the lid member 115 and serve with their outer heads 135, 136 on the upper side 25 of the lid part 115 and thus of the housing 2 as Außenanschlüsse22 and 23.

In the in Fig. 4 shown switching position spring snap disk 121 and bimetal 122 push the contact plate 124 against the stationary contacts 131st and 132, which are thus connected to each other via the contact surfaces 127; the switch 1 "is thus closed.

Increases the temperature of the bimetallic disc 122 beyond its response temperature, it snaps from the convex shown in a concave shape and supports itself with its edge in the region of the ring 117 and pulls the contact plate 124 against the force of the spring snap disc 121st away from the stationary contacts 131, 132; Switch 1 "is now open.

The switch described so far is from the DE 198 27 113 C2 However, the lid part 115 is made of insulating material. Like the one from the DE 198 27 113 C2 Known switch, the lid member 115 may alternatively be made of a PTC resistor 26, so represent a PTC resistor, which is electrically connected between the stationary contacts 131, 132. The lid part 115 then acts as a self-holding resistor.

Fig. 5 shows a plan view of the switch 1 "in a representation like Fig. 3 , Here, too, a connection line 27, 28 with their respective stripped end 29, 31 soldered to the outer terminals 22, 23 each.

The switches 1 and 1 "are used in a schematically indicated shielding pot 41, which serves in a manner to be described, the electromagnetic shielding of the switches 1, 1 'and consists of an electrically conductive, metallic material, preferably as a turned part is made of steel.

Fig. 6 shows above a schematic side view of the switch 1 "', where there are attached to the outer heads 135, 136 of the contact rivets 133, 134, ie to the pads 22, 23 contact angle 137 and 138 with their short legs 139, 140, wherein at the upstanding long legs 141, 142 are each soldered to a connecting line 27, 28 with their respective stripped ends 29, 31. The housing 2 has an outer diameter designated 39 and between the lower side 24 and upper side 25 a height designated 40 on.

Under the switch 1 '"is in Fig. 6 in a sectional side view of the FIGS. 3 and 5 known shielding pot 41 is shown, which has a circumferential, here cylindrical wall 42 and is closed at the bottom by a flat bottom 43 having a support surface 44. Opposite the bottom 43, the shielding pot 41 has an insertion opening 45, through which the switch 1 '"with its underside 25 is first inserted, which thereby comes to lie on the support surface 44.

The shielding pot 41 has between bearing surface 44 and insertion opening 45 with a designated insertion depth, which is slightly, at least 10% greater than the height 40 of the housing 2. The shielding pot 41 has an inner diameter 47 which is slightly larger than the outer diameter 39 of the housing 2, so that the housing 2 can be inserted into the shielding pot 41 and the wall 42 thereafter tight against the wall 113 of the housing 2.

The bottom 43 has a thickness designated 48 and the wall 42 has a thickness designated 49. With 50, the outer diameter of the shielding pot 41 is designated.

The shielding pot 41 is made of an electrically conductive, metallic material such as steel, for example, a deep-drawn sheet steel grade DC. The insertion depth 46 is for example 5 mm, the outer diameter 50 is for example 10 mm, and the thicknesses 48 and 49 are, for example, about 0.5 mm in each case. The height 40 is then, for example, 4 mm, so that the wall 43 protrudes about 1 mm above the top 24 when the housing 2 is inserted into the shielding pot 41.

In Fig. 7 the switch 1 '"is shown in this state inserted into the shielding pot 41, wherein the shielding pot 41 is cut in. The switch 1'" in Fig. 7 is opposite to the representation of Fig. 6 rotated 90 ° counterclockwise, so that the contact angle 137 can be seen from the side. The soldered to the long legs 141, 142 connection lines 28, 27 protrude vertically upwards out of the shielding pot 41.

In the next manufacturing step, the peripheral wall 42 is bent at its upper edge 51, which is easy to do, because the connecting lines are facing upwards.

The housing 2 is now on the bottom surface 24 on the support surface 44 and is held captive in the shielding pot 41 about the after insertion of the housing slightly inward, so on the top 25 of the housing 2 to bent upper edge 51 of the wall 42.

The shielding pot 41 establishes the thermal contact with the device to be protected via its underside 52. Because the housing 2 is in thermal contact with the support surface 44 via its lower surface 24 and in thermal contact with the wall 42 via its wall 113, it is thermally connected to the device to be protected. The quality of the thermal connection is determined by the strength of the mechanical system between the housing 2 and shielding pot 4 and by the material from which the Abschirmtopf is made, which is also a good thermal conductor because of its electrical conductivity.

Because the peripheral wall 42 with the edge 51 projects beyond the upper side 25, the shielding pot 41 shields the housing 2 not only from electromagnetic fields, it also protects it mechanically against pressure loads from above and from the side. This is particularly advantageous for switches whose cover part 12 consists of PTC thermistor material or insulating material.

In the next production step, the two long legs 141, 142 are bent along the arrow 53 to the short legs 139, 140, so that the long legs 141, 142 extend approximately parallel to the top 245 and the connecting lines 28, 27 upwards and laterally lead out of the connection pot 41.

When final assembly of the new switch so prefabricated switches are 1,1 'and 1 "used as needed from above into a shielding pot 41 and held in this positive and / or non-positive.

When at the switches 1 and 1 'off Fig. 3 or 5 of the edge 51 is bent inwardly, namely they are held captive in the Abschirmtopf 41 through which their connecting lines 28, 27 protrude laterally.

For all examples according to Fig. 3, 5 and 7 (After bending over of the long legs 141, 142), the insertion opening 45 surrounded by the edge 51 is now closed with a cast resin cover or other suitable electrical insulating material. For this purpose, an electrical insulating material 54 is placed within the edge 51 on the top 25, which covers the entire top 25 and thus the stripped ends 29, 31 and extending on the top 25 portions of the connecting lines 27, 28, as shown in the plan view of Fig. 8 is shown.

After curing of the Elektroisoliermaterials 54 this provides not only for protection of the pads 22, 23, the stripped ends 29, 31 and the cover member 12 and 115 from mechanical damage and unwanted electrical contact, it protects the switch as a whole against the ingress of contaminants , Further, the cured electrical insulating material 54 holds the housing 2 immovably fixed in the shielding pot 41st

In Fig. 9 is the switch off Fig. 8 in side view with cut connecting lines 27, 28 shown. In Fig. 9 It can be seen that the Elektroisoliermaterial 54 projects beyond the shielding pot 4 upwards and is curved, so that the top of the housing 2 is mechanically and electrically protected.

By means of the shielding pot 41 made of steel, the switches 1, 1 ', 1 "are significantly better protected against the action of electromagnetic fields than if the relevant switch without shielding pot 41 were used, where the influences of the electromagnetic fields on the bimetallic disks and on opening resulting arcing can lead to malfunction or shorten the life.

Claims (6)

1. A temperature-dependent switch comprising a housing (2), which housing has a cover part (12; 115) and a lower part (11; 114), said lower part comprising a peripheral wall (10; 113) and a bottom side (24), a temperature-dependent switching mechanism (15; 111), which switching mechanism is arranged in the housing (2) and which, depending on its temperature, produces or opens an electrically conductive connection between two external connection terminals (22, 23) provided on an upper surface (25) of the housing (2), and a shielding cup (41) made of an electrically conductive, metal material, into which the housing (2) is inserted with its bottom side (24) first, and which shielding cup comprises a peripheral wall (42), which peripheral wall at the top delimits an insertion opening (45) and at the bottom is terminated by a base (43), both external connection terminals (22, 23) being provided with connection lines (27, 28) which lead out from the shielding cup (41) at the top,
   characterized in that the peripheral wall (42) is bent over at its upper rim (51) toward the upper surface (25) of the housing (2), contact angles (137, 138) are fastened via their short branches (139, 140) to the external connection terminals (22, 23), the connection lines (27, 28) being fastened to the long branches (141, 142) of said contact angles, and the long branches (141, 142) are bent over toward the short branches (139, 140).
2. The switch as claimed in claim 1, characterized in that the shielding cup (41) is manufactured from steel.
3. The switch as claimed in claim 1 or claim 2, characterized in that the shielding cup (41) has an insertion depth (46) which corresponds at least to the height (40) of the housing (2) between the upper surface (25) and bottom side (24).
4. The switch as claimed in claim 3, characterized in that the insertion depth (46) is at least 10 % greater than the height (40).
5. The switch as claimed in anyone of claims 1 to 4, characterized in that an electrically insulating material (54), preferably a silicone adhesive, one-component thermosetting plastic or a resin, is applied to the upper surface (25) and covers at least the two external connection terminals (22, 23) and connects the shielding cup (41) to the housing (2).
6. A method for the final assembly of a temperature-dependent switch as claimed in anyone of claims 1 to 5, comprising the following steps:

   a) providing a temperature-dependent switch (1; 1'; 1") comprising a housing (2), which housing has a cover part (12; 115) and a lower part (11; 114), and a temperature-dependent switching mechanism (15; 111), which switching mechanism is arranged in the housing (2) and which, in depending on its temperature, produces or opens an electrically conductive connection between two external connection terminals (22, 23) provided on the switch (1, 1', 1"),

   b) connecting each a connection line (27, 28) to each one of the external connection terminals (22, 23), in that two contact angles (137, 138) are fastened via their respective short branch (139, 140) to one of the two external connection terminals (22, 23), each one of the two connection lines (27, 28) being fastened to a long branch (141, 142) of said contact angles;

   c) inserting the switch (1; 1'; 1") with the bottom side (24) first into a shielding cup provided with a peripheral wall (42) which at the top delimits an insertion opening (45) and at the bottom is terminated by a base (43), the shielding cup (41) consisting of an electrically conductive, metal material, such that the connection lines (27, 28) lead out upwardly from the shielding cup (41), the peripheral wall (42) is being bent over at its upper rim (51) toward the upper surface (25) of the housing (2), and then the long branches (141, 142) are being bent over toward the short branches (139, 140); and

   d) applying an electrically insulating material (54) to the upper surface (25) of the housing (2), such that the electrically insulating material (54) covers at least the external connection terminals (22, 23) provided on the upper surface (25); and

   e) allowing the electrically insulating material (54) to cure.

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