Temperature-dependent switching device and temperature-dependent switch with such a switching device

Description

[0001] The present invention relates to a temperature-dependent switching mechanism for a temperature-dependent switch. The present invention further relates to a temperature-dependent switch with such a temperature-dependent switching mechanism.

[0002] Temperature-dependent switches are already known in many different forms. An example of a temperature-dependent switch is disclosed in DE 10 2011 119 632 B3.

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

[0004] The switch is typically connected electrically in series via connecting cables into 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.

[0005] In the switch known from DE 10 2011 119 632 B3, the switching mechanism is arranged inside a switch housing. The switch housing is constructed in two parts. It has a lower part which is firmly connected to a cover part with an insulating film in between. The temperature-dependent switching mechanism arranged in the switch housing has a spring snap-action disc, to which a movable contact part is attached, and a bimetallic snap-action disc placed over the movable contact part. The spring snap-action disc presses the movable contact part against a stationary counter-contact arranged on the inside of the switch housing on the cover part. With its outer edge, the spring snap-action disc is supported in the lower part of the switch housing, so that the electrical 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.

[0006] The temperature-dependent bimetallic snap-action disc is primarily responsible for the switch's temperature-dependent switching behavior. This is usually a multi-layer, active, sheet-metal component made of two, three, or four interconnected components with different thermal expansion coefficients. The individual layers of metals or metal alloys in such bimetallic snap-action discs are usually bonded or positively connected, for example, by rolling.

[0007] Such a bimetallic snap-action disc exhibits a first stable geometric configuration (low-temperature configuration) at low temperatures, below the response temperature of the bimetallic snap-action disc, and a second stable geometric configuration (high-temperature configuration) at high temperatures, above the response temperature of the bimetallic snap-action disc. Depending on the temperature, the bimetallic snap-action disc jumps from its low-temperature configuration to its high-temperature configuration in a hysteresis-like manner.

[0008] If the temperature of the bimetallic snap-action disc rises above its operating temperature due to a temperature increase in the device to be protected, it switches from its low-temperature configuration to its high-temperature configuration. The bimetallic snap-action disc works against the spring-loaded snap-action disc, lifting the movable contact part from the stationary counter-contact, causing the switch to open and the device to be protected to be switched off, preventing it from heating up further.

[0009] If no return lock is provided, the bimetallic snap-action disc snaps back into its low-temperature configuration so that the switch is closed again as soon as the temperature of the bimetallic snap-action disc drops below the so-called return temperature of the bimetallic snap-action disc as a result of the cooling of the device to be protected.

[0010] In its low-temperature configuration, the bimetallic snap-action disc is preferably mounted in the switch housing in a mechanically force-free manner, whereby the bimetallic snap-action disc is also not used to conduct the current. This has the advantage that the bimetallic snap-action disc has a longer service life and that the switching point, i.e., the response temperature of the bimetallic snap-action disc, remains unchanged even after many switching cycles.

[0011] In many temperature-dependent switches, the bimetallic snap-action disc is therefore preferably inserted into the switch housing as a loose individual part during manufacture. The bimetallic snap-action disc, for example, is placed over the contact part attached to the spring-loaded snap-action disc using a central through-hole provided therein. Only when the switch housing is closed is the bimetallic snap-action disc then fixed in place and its position relative to the other components of the switching mechanism determined. However, the production of such a switch, in which the bimetallic snap-action disc is inserted individually, has proven to be relatively complicated, since several steps are necessary to insert the switch into the switch housing.

[0012] In the switch known from DE 10 2011 119 632 B3, the bimetallic snap-action disc is therefore already connected in advance (outside the switch housing) to the contact piece attached to the spring-loaded snap-action disc. To do this, the bimetallic snap-action disc is slipped over the contact piece, and then an upper collar of the contact piece is folded over. As a result, not only is the spring-loaded snap-action disc attached to the contact piece, but the bimetallic snap-action disc is also held captive to it.

[0013] The switch mechanism, consisting of the bimetallic snap-action disc, the spring-loaded snap-action disc, and the contact part, can thus be manufactured in advance as a semi-finished product, forming a captive unit that can be stored separately as bulk material. During switch manufacturing, the switch mechanism can then be installed into the switch housing as a captive unit in a single step. This simplifies switch production considerably.

[0014] The spring-loaded snap-action disc in the switch known from DE 10 211 119 632 B3 is welded or soldered to the contact part to ensure the best possible electrical contact between the two components. However, it has been shown that, particularly during bulk storage of the prefabricated switchgear as a semi-finished product, the welded or soldered connection between the contact part and the spring-loaded snap-action disc can break. Such defective switches can then, of course, no longer be used. A particular problem is that such a defect can only be detected after the switch has been assembled, since only then is a functional test of the switchgear possible.

[0015] DE 199 19 648 A1 also proposes a temperature-dependent switch whose switching mechanism can be produced in advance as a semi-finished product. In this switching mechanism, too, the bimetallic snap-action disc, the spring-loaded snap-action disc, and the contact part form a captive unit even before installation in the switch housing. This unit can be inserted into the switch housing as a whole during production of the switch and can be stored in advance as bulk material. In this switching mechanism, the contact part has a casing made of softer metal and a core made of electrically conductive, harder metal. The bimetallic snap-action disc and the spring-loaded snap-action disc are plugged onto the casing and molded into the softer metal of the casing. However, it has been found that this type of connection often leads to the bimetallic snap-action disc and / or the spring-loaded snap-action disc becoming accidentally detached from the contact part during storage of the switching mechanism.

[0016] Another option for pre-producing the switching mechanism as a semi-finished product is known from DE 29 17 482 A1 and DE 10 2007 014 237 A1. The captive unit of the switching mechanism is achieved by connecting the bimetallic snap-action disc and the spring-loaded snap-action disc with a rivet. Depending on the design of the switch, this rivet can also form the movable contact part of the switching mechanism. The rivet is constructed in two parts and comprises a rivet bolt that interacts with a hollow rivet or a rivet bolt with an attached counterholder.

[0017] While this type of riveted connection between the spring snap-action disc and the bimetallic snap-action disc has proven to be a mechanically durable connection, the riveted connection does have other disadvantages. For example, the bimetallic snap-action disc is usually clamped tightly to the rivet, which can lead to deformation and thus malfunction of the bimetallic snap-action disc. Overall, storage of the switchgear in bulk is therefore generally possible. However, damage to the switchgear during bulk storage cannot be ruled out.

[0018] DE 10 2013 017 232 A1, which forms the basis for the preamble of claim 1, discloses a temperature-dependent switching mechanism with a bimetallic snap-action disc, a movable contact member and a spring snap-action disc, wherein the switching mechanism has an annular frame in which the bimetallic snap-action disc and the spring snap-action disc are held captively.

[0019] Further exemplary temperature-dependent switches are disclosed in WO 2010 / 139781 A1 and DE 72 29 393 U.

[0020] It is therefore an object of the present invention to provide a temperature-dependent switching mechanism that can be pre-produced as a semi-finished product and stored in bulk without being susceptible to damage that could lead to a defect in the switching mechanism. The pre-produced switching mechanism as a semi-finished product should then be as easy to use as possible in a temperature-dependent switch and enable its production with as few work steps as possible. Furthermore, a functional test of the switching mechanism should be possible even before its installation in the switch.

[0021] This object is achieved according to the invention by a temperature-dependent switching mechanism according to claim 1, comprising: a temperature-dependent bimetallic snap-action disc; a temperature-independent spring snap-action disc; an electrically conductive contact part on which the bimetallic snap-action disc and the spring snap-action disc are held captively, so that the bimetallic snap-action disc, the spring snap-action disc, and the contact part form a switching unit held together captively; and a switching unit housing in which the switching unit is arranged and which holds the switching unit captively; wherein the switching mechanism housing at least partially surrounds the switching mechanism unit from a first housing side, a second housing side opposite the first housing side, and a housing peripheral side extending between and transversely to the first and second housing sides, wherein the switching mechanism housing is designed as an at least partially open housing and has an opening on the first housing side through which the contact part is accessible from outside the switching mechanism housing, wherein the switching mechanism housing has a side wall forming the housing peripheral side, the free, upper section of which is bent over and forms the first housing side, and wherein the bimetallic snap-action disk is configured to snap from a geometrically stable low-temperature configuration into a geometrically stable high-temperature configuration when a response temperature is exceeded,and wherein the bimetallic snap disc, in its low-temperature configuration, is spaced from an inner surface of the bent portion arranged inside the switchgear housing and, in its high-temperature configuration, is supported on the inner surface of the bent portion.

[0022] According to the invention, the switching mechanism comprises an additional switching mechanism housing in which the switching mechanism unit, which has the bimetallic snap-action disc, the spring snap-action disc and the contact part, is held captively but with play.

[0023] Similar to the prior art cited at the beginning, the bimetallic snap-action disc, the spring-loaded snap-action disc and the contact part form a captively held together switching unit, which can be pre-produced as a semi-finished product before being inserted into a temperature-dependent switch.

[0024] However, this derailleur unit is now additionally enclosed by a derailleur housing, so that the fragile components of the derailleur, especially the bimetallic snap-action disc and the spring-loaded snap-action disc, are protected by the derailleur housing during bulk storage. Damage to these fragile components during bulk storage is thus largely eliminated, as the fragile components of the derailleur are safely encapsulated in this derailleur housing.

[0025] However, the switchgear housing not only offers the advantage of safe storage of the fragile switchgear components during bulk storage, it also enables a much simpler way of manufacturing the temperature-dependent switch in which the switchgear is later used.

[0026] Unlike a conventional switch housing, the additional switch housing is not a closed housing in which the switch is hermetically sealed, but rather a partially open housing with an opening on the first side of the housing through which the contact part is accessible from outside the switch housing. The switch housing, together with the switch housing, can thus be inserted as a unit into a simplified switch housing, which forms the final switch housing. A counter contact can be arranged on this switch housing, which interacts with the externally accessible contact part of the switch. No modification or further processing of the switch housing is necessary.

[0027] During the production of the temperature-dependent switch, the switchgear according to the invention, including the switchgear housing, can initially be pre-produced as a semi-finished product and then inserted as a whole into a switch housing. This not only simplifies the storage of the switch but also the production of the temperature-dependent switch considerably.

[0028] Since all components of the switch are already arranged ready for use on the semi-finished switchgear, the switch housing surrounding the switchgear housing only needs to have two contacts that are electrically connected to one another via the switchgear. No further complex components need to be provided on the switch housing. It is therefore also possible to insert the switchgear according to the invention directly into an external switch housing that is designed integrally with the device to be monitored and is constructed significantly simpler than conventional switch housings that hermetically seal the switchgear. Of course, it is also possible to insert the switchgear together with its switchgear housing into a conventional switch housing, as is known, for example, from DE 10 2011 119 632 B3.

[0029] A further advantage of the switching mechanism according to the invention is that its functionality can be tested even before installation in the switch or switch housing. Due to the switch housing now provided, in which the switching mechanism unit is encapsulated, the snap-action behavior of the bimetallic snap disc can be tested in the switching mechanism housing.

[0030] The derailleur can be manufactured very easily by flanging the upper section of the side wall. This bent upper section of the side wall then at least partially surrounds the derailleur unit from the first housing side. However, as already mentioned, the first housing side is partially open because the bent upper section of the side wall does not cover the entire first housing side, but leaves an opening there through which the contact part is accessible from outside the derailleur housing. The opening preferably forms a central part in the middle of the first housing side. A free, circumferential edge of the bent section preferably delimits the opening radially.

[0031] The bent upper section of the side wall forming the first housing side of the derailleur housing not only serves to captively hold the derailleur unit in the derailleur housing, but also functions, according to the invention, as a support against which the bimetallic snap-action disc rests from the inside in its high-temperature configuration. This ensures that the derailleur, including its derailleur housing, can be used fully functionally even without a switch housing. In its high-temperature configuration, the bimetallic snap-action disc can rest against the derailleur housing itself, allowing the contact part connected to the bimetallic snap-action disc to move within the derailleur housing when the bimetallic snap-action disc snaps. A functional test of the derailleur can therefore easily be carried out even before the derailleur is installed in the switch.

[0032] The two configurations of the bimetallic snap-action disc mentioned above refer to different geometric positions of the bimetallic snap-action disc. In the low-temperature configuration or low-temperature position, the bimetallic snap-action disc is preferably convexly curved on its upper side. In the high-temperature configuration or high-temperature position, the bimetallic snap-action disc is preferably concavely curved on its upper side.

[0033] The above-mentioned task is thus completely solved.

[0034] Preferably, the second housing side and the housing peripheral side are each designed as closed housing sides and only the first housing side is designed as a partially open housing side (due to the opening provided thereon).

[0035] According to one embodiment, the contact part permanently projects outwards through the opening or is movable together with the bimetallic snap-action disc and the spring snap-action disc within the derailleur housing in such a way that the contact part projects outwards through the opening upon corresponding movement within the derailleur housing.

[0036] This ensures easy access to the contact part from outside the derailleur housing. This simplifies the electrical connection and contacting of the derailleur. The contact part is thus at least partially accessible from the outside, so that the switch housing of the final switch only needs to have a first contact, which is electrically connected to the derailleur housing, and a second contact, which acts as a counter contact to the contact part of the derailleur.

[0037] As already mentioned, the present invention relates not only to the temperature-dependent switching mechanism itself, but also to a temperature-dependent switch which, in addition to the temperature-dependent switching mechanism according to the invention, comprises a switch housing surrounding the switching mechanism, which has a first contact and a second contact, wherein the switching mechanism is designed to establish an electrical connection between the first and the second contact below a response temperature of the bimetallic snap-action disk and to interrupt the electrical connection when the response temperature is exceeded.

[0038] According to a further embodiment of the temperature-dependent switching mechanism, a diameter of the opening is smaller than a diameter of the bimetallic snap-action disc measured parallel thereto and / or smaller than a diameter of the spring snap-action disc measured parallel thereto.

[0039] The derailleur unit, which comprises the bimetallic snap-action disc, the spring-loaded snap-action disc, and the contact element, is thus held captive in the derailleur housing in a simple manner, but with some play. This ensures that the derailleur unit cannot accidentally detach from the derailleur housing, even during bulk storage.

[0040] According to a further embodiment, the switchgear housing is designed as a single piece. It preferably consists of a single piece from which all housing sides are integrally formed. This reduces the total number of parts and thus the costs. At the same time, it contributes to a highly pressure-resistant design of the switchgear. This is advantageous not only during storage of the switchgear as bulk material, but also in the final installed state, in which the switchgear is incorporated into the temperature-dependent switch.

[0041] According to a further embodiment, the derailleur housing comprises an electrically conductive material. The derailleur is preferably made of an electrically conductive material. This electrically conductive material is particularly preferably a metal.

[0042] This design allows the switchgear housing to be used as the current-carrying component of the temperature-dependent switch. In principle, it is also possible to use the switchgear housing itself as one of the two electrical contacts in the temperature-dependent switch. This simplifies the switch's design and enables very simple electrical connection.

[0043] According to a further embodiment, the derailleur housing has a dome- or cup-shaped section that forms at least part of the second housing side. This dome- or cup-shaped section preferably forms a centrally arranged part of the second housing side.

[0044] The dome-shaped or cup-shaped section ensures the freedom of movement of the derailleur unit located within the derailleur housing. This creates space for the contact part in a simple and space-saving manner as it moves from its low-temperature to its high-temperature configuration within the derailleur housing when the bimetallic snap disc snaps over.

[0045] According to a further embodiment, the derailleur housing is designed to be rotationally symmetrical around a central axis. This simplifies the installation of the derailleur, including its housing, into a switch housing of the temperature-dependent switch, since the derailleur can be inserted into the temperature-dependent switch in various positions rotated around the central axis. Furthermore, the rotationally symmetrical design of the derailleur housing enables even force distribution in all directions (radial directions).

[0046] According to a further embodiment, the bimetallic snap-action disc has a first through-hole and the spring snap-action disc has a second through-hole, wherein the contact part is guided through the first through-hole and the second through-hole, wherein the contact part further has a support shoulder protruding radially from the base body, a first locking element arranged on a first side of the support shoulder, and a second locking element arranged on a second side of the support shoulder opposite the first side. The bimetallic snap-action disc is arranged between the first locking element and the support shoulder and is held captively on the contact part by the first locking element and the support shoulder, but with play.The spring snap-action disc is arranged between the second locking element and the support shoulder and is held captive by the second locking element and the support shoulder, but with play, on the contact part.

[0047] The locking elements can each be one or more retaining claws that protrude radially from the base body of the contact part. Alternatively, the locking elements can each have a flanged collar that extends circumferentially around the base body of the contact part. Both the retaining claws and this bent collar can form individual circumferential sections of the base body or extend around the entire circumference of the base body. In this way, the two snap discs are held captive to the base body, but with some play.

[0048] The locking elements for holding and locking the bimetallic snap-action disc and the spring-action disc are preferably integrally connected to the base body of the contact part, whereby they can be produced by forming a respective part of the base body. The contact part is thus formed as a single piece, and the base body of the contact part is integrally connected to the support shoulder and the locking elements. Overall, the contact part, the bimetallic snap-action disc, and the spring-action disc can be combined to form a switching mechanism unit consisting of only three parts, which is implemented as a captive unit.

[0049] The three-part design of the derailleur unit has the advantage of requiring as few necessary components as possible, as well as the advantage of a mechanically stable and robust design of the derailleur.

[0050] According to a further embodiment, the first through-hole is arranged centrally in the bimetallic snap-action disc. Likewise, the second through-hole is preferably arranged centrally in the spring snap-action disc.

[0051] The bimetallic snap-action disc and the spring-action disc are preferably each circular disc-shaped. Furthermore, the bimetallic snap-action disc and the spring-action disc are preferably each bistable.

[0052] In this context, "bistable" means that both snap-action discs each have two different, stable geometric configurations / positions, with the two stable configurations / positions of the bimetallic snap-action disc being temperature-dependent, and the two stable configurations / positions of the spring-action disc being temperature-independent. This ensures that the two snap-action discs remain stable in their respective positions after snapping from one configuration to the other, without undesired snapping back. Snapping of the switching mechanism therefore only occurs when the response temperature of the bimetallic snap-action disc is exceeded and the return temperature of the bimetallic snap-action disc is undershot. The spring-action disc snaps into its other configuration / position together with the bimetallic snap-action disc.

[0053] It is understood that the features mentioned above and those to be explained below can be used not only in the respective configuration specified, but also in other combinations or on their own, without departing from the scope of the present invention.

[0054] Embodiments of the invention are illustrated in the drawings and explained in more detail in the following description. They show: Fig. 1 is a schematic sectional view of the temperature-dependent switching mechanism according to a first embodiment of the present invention; Fig. 2 is a schematic sectional view of the temperature-dependent switching mechanism according to a second embodiment of the present invention; Fig. 3 is a schematic sectional view of the temperature-dependent switch according to an embodiment of the present invention, wherein the switch is in its low-temperature position; Fig. 4 is a schematic sectional view of the Fig. 3 shown temperature-dependent switch, wherein the switch is in its high-temperature position; and Fig. 5 is a schematic sectional view of another embodiment of the temperature-dependent switch, wherein the switch is in its low-temperature position.

[0055] Fig. 1-2show two different embodiments of the switching mechanism according to the invention, each in a schematic sectional view. The switching mechanism is designated in its entirety by reference numeral 10.

[0056] The derailleur 10 is a temperature-dependent derailleur. It comprises a functional derailleur unit 12 and a derailleur housing 14 surrounding this derailleur unit 12. The derailleur housing 14 surrounds the derailleur unit 12 from all six spatial directions, at least partially in each case. As explained in detail below, however, the derailleur housing 14 is designed as a partially open housing, so that the derailleur unit 12 is accessible from at least one spatial direction, preferably from only one spatial direction, from outside the derailleur housing 14.

[0057] Due to the fact that the derailleur housing 14 at least partially surrounds the derailleur unit 12 from all six spatial directions, the derailleur unit 12 is held captively in the derailleur housing 14. As long as the derailleur 10 is not inserted into a temperature-dependent switch, a certain amount of play preferably exists between the derailleur unit 12 and the derailleur housing 14. The derailleur unit 12 is movable within the derailleur housing 14 in the low-temperature position of the derailleur 10.

[0058] The switching unit 12 is constructed in three parts. The switching unit 12 comprises a temperature-dependent bimetallic snap-action disc 16, a temperature-independent spring-action disc 18, and a contact part 20. The bimetallic snap-action disc 16 and the spring-action disc 18 are held captively on the contact part 20.

[0059] The switching unit 12 can thus be pre-produced as a semi-finished product and then inserted as a whole into the switching housing 14. The switching unit 10, together with the switching unit 12 and the switching housing 14, then also form a semi-finished product for a temperature-dependent switch that will later be produced from it.

[0060] Since both the three components 16, 18, 20 of the switching unit 12 are captively connected to one another and the switching unit 12 is captively held in the switching housing 14, the switching unit 10 can be stored as bulk material until it is installed in a temperature-dependent switch.

[0061] The switchgear housing 14 protects the fragile components of the switchgear unit 12, in particular the bimetallic snap-action disk 16 and the spring-loaded snap-action disk 18, from damage during bulk material storage. Installing the switchgear unit 12 in such a switchgear housing 14 also has the advantage that the switchgear 10 can be very easily integrated into a temperature-dependent switch being manufactured. Due to this very simple handling of the switchgear, the assembly process of the temperature-dependent switch can be easily automated.

[0062] The derailleur housing 14 surrounds the derailleur unit 12 from a first housing side 22, a second housing side 24 opposite the first housing side 22, and a housing peripheral side 26 running between and transversely to the first and second housing sides 22, 24, in each case at least partially. The derailleur housing 14 preferably completely surrounds the derailleur unit 12 from both the second housing side 24 and the housing peripheral side 26. The second housing side 24 and the housing peripheral side 26 therefore preferably form closed housing sides of the derailleur housing 14. Only the first housing side 22 is a partially open housing side of the derailleur housing 14. In other words, the housing peripheral side 26 surrounds the derailleur unit 12 along the entire circumference, i.e. from a total of four mutually orthogonal spatial directions.Furthermore, the derailleur housing 14 also completely surrounds the derailleur unit 12 from a further spatial direction, namely a spatial direction oriented orthogonally to the second housing side 24. Only from the sixth spatial direction, which is oriented orthogonally to the first housing side 22, does the derailleur housing 14 only partially surround the derailleur unit 12.

[0063] On the first housing side 22, the derailleur housing 14 has an opening 28 through which the contact part 20 is accessible from outside the derailleur housing 14.

[0064] According to the two Fig. 1 and 2In the illustrated embodiments of the derailleur 10, the contact part 20 permanently protrudes outward through the opening 28. Depending on the height of the derailleur housing 13, however, this need not necessarily be the case. In principle, it is sufficient if the contact part 20 is accessible from the outside through the opening 28 and the derailleur unit 12 is movable within the derailleur housing 14 such that the contact part 20 protrudes outward through the opening 28 upon a corresponding movement within the derailleur housing.

[0065] A diameter D 1 of the opening 28 is smaller than a diameter D 2 of the bimetallic snap-action disc 16 and / or the spring snap-action disc 18 measured parallel thereto. Thus, although the contact part 20 is accessible from the outside through the opening 28, the bimetallic snap-action disc 16 and the spring snap-action disc 18 cannot detach from the switching mechanism housing 14.

[0066] The derailleur housing 14 is constructed in one piece and is made of an electrically conductive material, for example, metal. It has a bottom wall 30 and a side wall 32 integrally connected to the bottom wall. The bottom wall 30 forms the second housing side 24 of the derailleur housing 14. The side wall 32 forms the peripheral side 26 of the derailleur housing 14. A free upper section 34 of the side wall 32 is bent toward a central axis 36, which forms the longitudinal axis of the contact part 20. A free, circumferential edge 38 of this bent upper section 34 delimits the opening 28 of the derailleur housing 14 in the radial direction.

[0067] In the Fig. 1 and 2In the low-temperature position of the switching mechanism 10 shown, the spring snap-action disc 18 rests with its outer edge against the switching mechanism housing 14. More precisely, the spring snap-action disc 18 rests with its outer edge on an inner side 40 of the base wall 30 facing the switching mechanism unit 12. In this position of the switching mechanism 10, the spring snap-action disc 18 supports the contact part 20. In this switching mechanism position, the bimetallic snap-action disc 16, on the other hand, is mounted in the switching mechanism housing 14 with more or less no force.

[0068] The two snap-action discs 16, 18 are preferably circular disk-shaped and each have a centrally located through-hole 42, 44. The through-hole 42 located centrally in the bimetallic snap-action disc 16 is referred to herein as the first through-hole. The through-hole 44 located in the spring snap-action disc 18 is referred to as the second through-hole.

[0069] The two snap-action discs 16, 18 are placed over the contact part 20 from opposite sides with their respective through holes 42, 44. Thus, the contact part 20 penetrates both snap-action discs 16, 18 at a central point.

[0070] The contact part 20 has a base body 46, which is preferably solid and made of an electrically conductive material. The base body 46 extends through the two through holes 42, 44.

[0071] Approximately in the middle, i.e. approximately halfway up, the contact part 20 has a support shoulder 48 projecting radially from the base body 46. The two snap discs 16, 18 rest against this support shoulder 48 from opposite sides. The bimetallic snap disc 16 is arranged on a first side of the support shoulder 48, which Fig. 1 and 2forms the upper side of the support shoulder 48. The spring snap-action disk 18 is arranged on a second side of the support shoulder 48 opposite the first side, which in Fig. 1 and 2 forms the underside of the support shoulder 48.

[0072] Furthermore, locking elements 50, 52 are formed on the contact part 20, by means of which the two snap discs 16, 18 are held on the contact part 20. The two locking elements 50, 52 protrude radially from the base body 46 of the contact part 20. The first locking element 50 is arranged on the first side of the support shoulder 48. The second locking element 52 is arranged on the opposite, second side of the support shoulder 48.

[0073] The bimetallic snap-action disk 16 is arranged between the first locking element 50 and the support shoulder 48 and is held captively on the contact part 20 due to the radial projection of the first locking element 50 and the support shoulder 48 between the first locking element 50 and the support shoulder 48.

[0074] The spring snap-action disk 18 is arranged between the second locking element 52 and the support shoulder 48 and is held captively on the contact part 20 due to the radial projection of the second locking element 52 and the support shoulder 48 between the second locking element 52 and the support shoulder 48.

[0075] The contact part 20, together with the support shoulder 48 and the two locking elements 50, 52, is formed as a single piece. The support shoulder 48 and the two locking elements 50, 52 are thus formed integrally with the base body 46 of the contact part 20.

[0076] In the Fig. 1 and 2In the illustrated embodiments, the two locking elements 50, 52 are each designed as a circumferentially extending collar. The circumferentially extending collar forming the first locking element 50 protrudes radially upwards from the base body 46 of the contact part 20. The collar forming the second locking element 52 protrudes radially downwards from the base body 46 of the contact part 20.

[0077] Both collars can be formed relatively easily by forming a circumferential cut notch into the contact part 20. The cut notches are formed into the contact part after the two snap discs 16, 18 with their through holes 40, 42 have been slipped over the contact part 20.

[0078] As an alternative to collars created by cutting notches, the two locking elements 50, 52 can also each have one or more retaining claws (not shown). Such retaining claws are also preferably formed integrally with the base body 46 of the contact part 20.

[0079] For the function of the switching mechanism 10, it is advantageous if the bimetallic snap-action disc 16 is held on the contact part 20 with greater play than the spring snap-action disc 18. This ensures sufficient freedom of movement of the bimetallic snap-action disc 16. At the same time, the slightly smaller play between the spring snap-action disc 18 and the contact part 20 enables the best possible electrical contact between these two components.

[0080] The two in Fig. 1 and 2 The embodiments of the rear derailleur 10 shown differ essentially in the shape of the rear derailleur housing 14. In the Fig. 1In the embodiment shown, the bottom wall 30, which forms the second housing side 24 of the switchgear housing 14, is essentially plate-shaped and has a pot-like bulge 54 in a central section. Fig. 2 In the embodiment shown, however, the bottom wall 30 is curved in cross-section. The bottom wall 30 of the derailleur housing 14 thus forms a kind of convex dome.

[0081] Of course, other shapes of the switch housing 14 are possible. However, it is important that the contact part 20 deviates from the position shown in the figure when the snap discs 16, 18 snap over. Fig. 1 and 2 shown low-temperature position to the high-temperature position within the switchgear housing 14. For this purpose, sufficient space must be available, in particular, for the contact part 20 so that it does not collide with the bottom wall 30 in the high-temperature position of the switchgear 10.

[0082] In Fig. 3 and 4 An embodiment of a temperature-dependent switch in which the switching mechanism 10 according to the invention can be used is shown in a schematic sectional view. The switch is designated in its entirety by the reference numeral 100.

[0083] Fig. 3 shows the low temperature position of switch 100. Fig. 4 shows the high temperature position of switch 100.

[0084] The switch 100 has, according to the Fig. 3 and 4 shown embodiment, a switch housing 56, which functions as a housing for the rear derailleur 10. The rear derailleur 10 is inserted into the switch housing 56 together with its rear derailleur housing 14. The rear derailleur 10 corresponds to the Fig. 1 shown embodiment.

[0085] The switch housing 56 comprises a pot-like lower part 58 and a cover part 60, which is held on the lower part 58 by a bent or flanged edge 62.

[0086] Both the lower part 58 and the cover part 60 are in the Fig. 3 and 4 In the embodiment shown, the housing is made of an electrically conductive material, preferably metal. An insulating film 64 is arranged between the lower part 58 and the cover part 60. The insulating film 64 provides electrical insulation between the lower part 58 and the cover part 60. Likewise, the insulating film 64 provides a mechanical seal that prevents liquids or contaminants from entering the housing interior from the outside.

[0087] Since the lower part 58 and the cover part 60 are each made of electrically conductive material, thermal contact with an electrical device to be protected can be established via their outer surfaces. The outer surfaces also serve as the external electrical connection of the switch 100. For example, the outer surface 61 of the cover part 60 can function as the first electrical connection, and the outer side 59 of the lower part 58 can function as the second electrical connection.

[0088] On the outside of the cover part 60, as shown in Fig. 3 and 4 shown, a further insulation layer 66 may be arranged.

[0089] The derailleur 10 is clamped between the lower part 58 and the cover part 60. A spacer ring 68, against which the derailleur housing 14 rests circumferentially, serves to position the derailleur 10. It is particularly important that the contact part 20 is aligned with a mating contact 70 located on the inside of the cover part 60. This mating contact 70 is also referred to herein as the first stationary contact. The inside 71 of the lower part 58 serves as the second stationary contact.

[0090] In the Fig. 3In the low-temperature position of the switch 100 shown, the temperature-independent spring snap-action disc 18 is in its first configuration and the temperature-dependent bimetallic snap-action disc 16 is in its low-temperature configuration. The spring snap-action disc 18 presses the contact part 20 against the mating contact 70. The switch 100 is thus in its closed position, in which an electrically conductive connection is established between the first stationary contact 70 and the second stationary contact 71 via the contact part 20 and the spring snap-action disc 18. The contact pressure between the contact part 20 and the first stationary contact 70 is generated by the spring snap-action disc 18. In this state, the bimetallic snap-action disc 16, however, is mounted in the switchgear housing 14 with virtually no force.

[0091] If the temperature of the device to be protected and thus the temperature of the switch 100 and the bimetal snap-action disc 16 arranged therein increases to the switching temperature of the bimetal snap-action disc 16 or above the switching temperature, the bimetal snap-action disc 16 snaps from its Fig. 3 shown convex low-temperature position into its concave high-temperature position, which is Fig. 4 is shown. During this snapping action, the bimetallic snap disc 16 rests with its outer edge on the first housing side 22 of the derailleur housing 14. More precisely, the bimetallic snap disc 16 rests on an inner surface 72 of the bent upper section 34 arranged inside the derailleur housing 14. As a result, the spring snap disc 18 simultaneously bends downwards at its center, so that the spring snap disc 18 is released from its Fig. 3 shown, first stable geometric configuration into its Fig. 4 shown, second geometrically stable configuration snaps over.

[0092] Fig. 4 shows the high-temperature position of switch 100, in which it is open. The circuit is thus interrupted.

[0093] When the device to be protected and thus the switch 100 including the bimetallic snap-action disc 16 cool down again, the bimetallic snap-action disc 16 snaps back into its low-temperature position when the reset temperature is reached, which is also referred to as the return temperature, as is the case, for example, in Fig. 3 This allows for reversible switching behavior.

[0094] Of course, it is also possible for a corresponding locking mechanism to prevent the switch 100 from switching back to the high-temperature position once it has snapped over. Such locking mechanisms, which are used particularly in one-shot switches where switching back is to be prevented, are already known in numerous prior art designs.

[0095] Fig. 5 shows a further embodiment of the switch 100 according to the invention. The switch housing 56 is in comparison to the one in Fig. 3 and 4The switch housing 56 shown here is designed much simpler. It has only one contact 70, which is connected to a first electrical terminal 61, and a second contact 71, which is connected to a second terminal 59. The two contacts 70, 71 are designed as simple metal sheets that are connected to one another via an insulator 76. The insulator 76 electrically separates the two contacts 70, 71 from one another and simultaneously provides a mechanical connection between the two contacts 70, 71.

[0096] The rear derailleur 10 is in the Fig. 5 shown embodiment is only inserted between the two contacts 70, 71. However, the switch housing 56 is partially open here and, unlike in the case of the Fig. 3 and 4 shown embodiment, not hermetically sealed.

[0097] The switch housing 56 of the switch 100 according to the Fig. 5The embodiment shown can, for example, be integrated directly into a device to be monitored by the switch 100. The simple structure of the Fig. 5 The switch housing 56 shown is intended to illustrate in principle that the switching mechanism 10 according to the invention, due to its structural design, can also be integrated into significantly simpler switch housings 56. The reason for this is, in particular, that the switching mechanism 10 is already fully functional in itself due to the switching mechanism housing 14, in which the switching mechanism unit 12 is captively mounted. If, for certain applications, hermetic sealing of the switch 100 is not necessary, only two contacts 70, 71 are required on the switch housing 56, between which the switching mechanism 10 is clamped. Other components are not required on the switch housing 56, apart from the electrical connections 59, 61 connected to the contacts 70, 71.

[0098] It is understood that the switching mechanism 10 according to the invention can be used in switch housings of completely different designs.

Claims

1. A temperature-dependent switching mechanism (10) for a temperature-dependent switch (100), having: - a temperature-dependent bimetal snap-action disc (16); - a temperature-independent snap-action spring disc (18); - an electrically conductive contact member (20) to which the bimetal snap-action disc (16) and the snap-action spring disc (18) are captively held, so that the bimetal snap-action disc (16), the snap-action spring disc (18), and the contact member (20) form a switching mechanism unit (12) captively held together; and - a switching mechanism housing (14) in which the switching mechanism unit (12) is arranged and which captively holds the switching mechanism unit (12); wherein the switching mechanism housing (14) surrounds the switching mechanism unit (12) from a first housing side (22), a second housing side (24) opposite the first housing side (22), and a housing peripheral side (26) extending between and transverse to the first and second housing sides (22, 24), and wherein the switching mechanism housing (14) is configured as an at least partially open housing and comprises an opening (28) on the first housing side (22) through which the contact member (20) is accessible from outside the switching mechanism housing (14), wherein the switching mechanism housing (14) comprises a side wall (32) forming the housing peripheral side (26), the free, upper portion (34) of which is bent over and forms the first housing side (22), and wherein the bimetal snap-action disc (16) is configured to snap from a geometrically stable low temperature configuration to a geometrically stable high temperature configuration upon exceeding a response temperature, characterized in that the bimetal snap-action disc (16) in its low temperature configuration is spaced from an inner surface (72) of the bent-over portion (34) arranged inside the switching mechanism housing (14) and in its high temperature configuration bears against the inner surface (72) of the bent-over portion (34).

2. The temperature-dependent switching mechanism of claim 1, wherein the contact member (20) permanently protrudes outwardly through the opening (28) or is movable together with the bimetal snap-action disc (16) and the snap-action spring disc (18) within the switching mechanism housing (14) such that the contact member (20) protrudes outwardly through the opening (28) upon a corresponding movement within the switching mechanism housing (14).

3. The temperature-dependent switching mechanism according to claim 1 or 2, wherein a diameter (D1) of the opening (28) is smaller than a diameter (D2) of the bimetal snap-action disc (16) measured parallel thereto and / or smaller than a diameter (D2) of the snap-action spring disc (18) measured parallel thereto.

4. The temperature-dependent switching mechanism according to one of the preceding claims, wherein the switching mechanism housing (14) is formed in one piece5. The temperature-dependent switching mechanism according to any one of the preceding claims, wherein the switching mechanism housing (14) comprises an electrically conductive material.

6. The temperature-dependent switching mechanism according to any one of the preceding claims, wherein the switching mechanism housing (14) comprises a dome-shaped or pot-shaped portion (54) forming at least a part of the second housing side (24).

7. The temperature-dependent switching mechanism according to any of the preceding claims, wherein the switching mechanism housing (14) is rotationally symmetrical about a central axis (36).

8. The temperature-dependent switching mechanism according to claims 6 and 7, wherein the dome- or pot-shaped portion (54) forms a centrally arranged part of the second housing side (24) and is rotationally symmetrical about the central axis (36).

9. The temperature-dependent switching mechanism according to claim 7 or 8, wherein the switching mechanism (10) is configured rotationally symmetrical about the central axis (36).

10. The temperature-dependent switching mechanism according to any one of the preceding claims, wherein the bimetal snap-action disc (16) comprises a first through hole (42) and the snap-action spring disc (18) comprises a second through hole (44), wherein the contact member (20) passes through the first through hole (42) and the second through hole (44), wherein the contact member (20) further comprises a radially projecting support shoulder (48), a first locking element (50) arranged on a first side of the support shoulder (48), and a second locking element (52) arranged on a second side of the support shoulder (48) opposite the first side, wherein the bimetal snap-action disc (16) is arranged between the first locking element (50) and the support shoulder (48) and is held captive on the contact member (20) by the first locking element (50) and the support shoulder (48), and wherein the snap-action spring disc (18) is arranged between the second locking element (52) and the support shoulder (48) and is held captive on the contact member (20) by the second locking element (52) and the support shoulder (48).

11. The temperature-dependent switching mechanism of claim 10, wherein the first through hole (42) is arranged centrally in the bimetal snap-action disc (16), and wherein the second through hole (44) is arranged centrally in the snap-action spring disc (18).

12. The temperature-dependent switching mechanism according to any one of the preceding claims, wherein the bimetal snap-action disc (16) and the snap-action spring disc (18) are each circular disc-shaped.

13. A temperature-dependent switch (100) comprising a temperature-dependent switching mechanism (10) according to any one of claims 1-12 and a switch housing (56) surrounding the switching mechanism (10) and having a first contact (70) and a second contact (71), wherein the switching mechanism (10) is configured to establish an electrical connection between the first and second contacts (70, 71) below a response temperature of the bimetal snap-action disc (16) and to interrupt the electrical connection upon exceeding the response temperature.