TEMPERATURE DEPENDENT SWITCH

Abstract

Temperature-dependent switch (10) comprising: a switch housing (12) with a lower part (16) and a cover part (18) closing the lower part (16);a temperature-dependent switching mechanism (14) which is arranged in the switch housing (12) and has a movable contact part (30), a bimetallic element (26) and a spring element (24) cooperating with the movable contact part (30), wherein the switching mechanism (14) is configured to switch between a low-temperature position, in which it presses the movable contact part (30) against a contact surface (34) arranged inside the switch housing (12) and thereby establishes an electrical connection between a first electrical external terminal (56) of the switch (10) and a second electrical external terminal (58) of the switch (10), and a high-temperature position, in which it keeps the movable contact part (30) spaced away from the contact surface (34) and thereby interrupts the electrical connection between the first electrical external terminal (56) and the second electrical external terminal (58);and a spacer element (44) which is arranged inside the switch housing (12) between the lower part (16) and the cover part (18); wherein at least one section (42) of the spring element (24) is arranged between the spacer element (44) and the switch housing (12) and is fixed in position by an interaction of the spacer element (44) and the switch housing (12), and wherein at least one section (52) of the bimetallic element (26) is arranged between the spring element (24) and the spacer element (44) and is supported on the spacer element (44) in the high-temperature position of the switching mechanism (14).

Description

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

[0002] Temperature-dependent switches are already known in many different forms. Examples of temperature-dependent switches are known from DE 10 2013 109 291 A1 and DE 10 2011 119 637 B4.

[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 2013 109 291 A1, the switching mechanism is arranged inside a switch housing. The switch housing is a closed housing in which the switching mechanism is sealed from the outside. The switch housing is constructed in two parts. It has a lower part, which is closed by a cover part. The cover part is attached to the lower part. For this purpose, the lower part has a raised, circumferential edge, the free upper edge of which is bent or flanged onto the cover part.

[0006] The temperature-dependent switching mechanism located in the switch housing comprises a spring element to which a movable contact part is attached, as well as a bimetallic element that interacts with the movable contact part. The spring element presses the movable contact part against a stationary counter-contact located on the inside of the switch housing on the cover. The outer edge of the spring element, designed as a spring-loaded snap-action disc, rests against the lower part of the switch housing, allowing the electrical current to flow from the lower part through the spring-loaded snap-action disc and the movable contact part into the stationary counter-contact and from there into the cover part.

[0007] A temperature-dependent bimetallic element is essentially responsible for the temperature-dependent switching behavior of the switching mechanism. In the switches known from DE 10 2013 109 291 A1 and DE 10 2011 119 637 B4, this element is disc-shaped and often referred to as a bimetallic snap-action disc. This bimetallic element is usually designed as a multi-layer, active, sheet-metal component consisting of two, three, or four interconnected components with different thermal expansion coefficients. The connection between the individual layers of metals or metal alloys in such bimetallic elements is usually materially bonded or positively bonded and is achieved, for example, by rolling.

[0008] Such a bimetallic element exhibits a first stable geometric configuration (low-temperature configuration) at low temperatures, below the response temperature of the bimetallic element, and a second stable geometric configuration (high-temperature configuration) at high temperatures, above the response temperature of the bimetallic element. Depending on the temperature, the bimetallic element jumps from its low-temperature configuration to its high-temperature configuration in a hysteresis manner.

[0009] If the temperature of the bimetallic element rises above its response temperature due to a temperature increase in the device to be protected, the bimetallic element switches from its low-temperature configuration to its high-temperature configuration. The bimetallic element works against the spring element to lift the movable contact part from the stationary counter-contact, causing the switch to open and the device to be protected to be switched off and prevent it from heating up further.

[0010] If no return lock is provided, the bimetal element snaps back into its low-temperature configuration so that the switch is closed again as soon as the temperature of the bimetal element drops below the so-called return temperature of the bimetal element as a result of cooling of the device to be protected.

[0011] In its low-temperature configuration, the bimetallic element is preferably mounted in the switch housing without mechanical forces, whereby the bimetallic element is also not used to conduct the current. This has the advantage that the bimetallic element has a longer service life and that the switching point, i.e., the response or switching temperature of the bimetallic element, remains unchanged even after many switching cycles.

[0012] In the switches known from DE 10 2013 109 291 A1 and DE 10 2011 119 637 B4, the spring element, designed as a spring-loaded snap-action disc, is in permanent contact with the lower part in the area of ​​its outer edge. In the switch from DE 10 2011 119 637 B4, part of the outer edge of the spring-loaded snap-action disc is integrally bonded to the lower part of the switch housing. In the switch from DE 10 2013 109 291 A1, the spring-loaded snap-action disc rests on a circumferential shoulder provided in the lower part and is clamped between this shoulder and a spacer element designed as a spacer ring, thereby mechanically securing it. In both cases, the spring-loaded snap-action disc is permanently galvanically connected to the current-carrying switch housing, both in the low-temperature position of the switchgear and in the high-temperature position of the switchgear.

[0013] The permanent galvanic connection of the spring-loaded snap-action disc to the current-carrying lower part of the switch housing ensures that the contact resistance between the spring-loaded snap-action disc and the lower part of the switch housing is very low. This eliminates a potential source of error that can arise during the final continuity test of a fully assembled temperature-dependent switch. Due to manufacturing tolerances, the contact resistance between the lower part of the housing and the spring-loaded snap-action disc may be so high that the finished temperature-dependent switch must be rejected.

[0014] Conversely, most switches known from the prior art are provided with spring elements whose edges rest loosely, i.e. freely movable, on the inner floor of the lower part of the switch housing or on a shoulder running around the inside of the lower part. A switch of this type is known, for example, from DE 43 45 350 A1. It is understood that such a loosely mounted spring element has considerably more mechanical degrees of freedom, so that the spring element can move more freely within the switch housing when the switching mechanism snaps between the low-temperature position and the high-temperature position (and vice versa). This has a fundamentally positive effect on the service life of the switching mechanism and the long-term stability of its switching temperature. On the other hand, the lack of a permanent galvanic connection between the spring element and the current-carrying switch housing results in the aforementioned disadvantages, i.e.in particular an increased reject rate and an increased contact resistance.

[0015] Against this background, the present invention is based on the object of providing a temperature-dependent switch in which the aforementioned disadvantages are prevented or at least largely reduced in a structurally simple manner. In particular, it is an object to provide a switch composed of as few components as possible, which is easy to install, and whose service life and / or switching capacity can be increased compared to previously known temperature-dependent switches.

[0016] According to the invention, this object is achieved by a temperature-dependent switch according to claim 1, which has the following components: a switch housing with a lower part and a cover part closing the lower part; a temperature-dependent switching mechanism which is arranged in the switch housing and has a movable contact part, a bimetallic element and a spring element cooperating with the movable contact part, wherein the switching mechanism is configured to switch in a temperature-dependent manner between a low-temperature position, in which it presses the movable contact part against a contact surface arranged inside the switch housing and thus establishes an electrical connection between a first electrical external terminal of the switch and a second electrical external terminal of the switch, and a high-temperature position, in which it keeps the movable contact part spaced from the contact surface and thus interrupts the electrical connection between the first electrical external terminal and the second electrical external terminal;and a spacer element arranged inside the switch housing between the lower part and the cover part; wherein at least a portion of the spring element is arranged between the spacer element and the switch housing and is fixed in position by the interaction of the spacer element and the switch housing, and wherein at least a portion of the bimetallic element is arranged between the spring element and the spacer element and is supported on the spacer element in the high-temperature position of the switching mechanism.

[0017] Similar to the switch known from DE 10 2013 109 291 A1, the spring element of the temperature-dependent switching mechanism in the switch according to the invention is also fixed in its position by a spacer element arranged inside the switch housing. More precisely, the spring element is fixed in its position by the interaction of the spacer element and the switch housing. This means that both the spacer element and the switch housing contribute to fixing the position of the spring element. Both the spacer element and the switch housing each exert a force on the spring element, thereby fixing it in its position. Direct contact between the spacer element and the spring element on the one hand, and between the switch housing and the spring element on the other hand, can, but does not necessarily have to, occur. The switch housing and the spacer element can also be indirectly connected to the spring element.

[0018] Unlike the switch known from DE 10 2013 109 291 A1, however, the spacer element in the switch according to the invention fulfills several functions simultaneously. It fulfills the two already known functions, namely, that it is designed to keep the base and cover parts at a distance from each other, and that it is designed to fix the spring element in its position. In addition, according to the invention, the spring element fulfills a third function, namely, that it serves as a counterbearing against which the bimetallic element can be supported in the high-temperature position of the switching mechanism.

[0019] This allows several functions to be fulfilled simultaneously with the help of a single component in the form of a spacer element. This not only simplifies the design of the switch but also its assembly. Furthermore, the latter additional function of the switch as a support for the bimetallic element also has a positive effect on the service life of the switch.

[0020] In the switches cited above, the bimetallic element in its high-temperature position is typically supported either by the spring element itself or by the cover of the switch housing. Supporting it on the spring element has the disadvantage that it is subjected to significant mechanical stress, particularly after many switching cycles, and can become damaged. Supporting it on the cover of the switch housing is less problematic, but requires, on the one hand, that the switching mechanism is precisely matched to the manufacturing tolerances of the housing components, and, on the other hand, that the bimetallic element in its high-temperature configuration usually has to bend very significantly until its outer edge reaches the cover and its center presses the movable contact part downwards.

[0021] However, thanks to the abutment provided on the spacer element, the manufacturing tolerances of the switching mechanism are now largely independent of those of the switch housing. Furthermore, the bimetallic element only needs to bend slightly, as the spacer element can be positioned very close to it and the spring element. Mechanical wear on the spacer element is also harmless, as it can be designed to be significantly more stable than the spring element, for example.

[0022] The above-mentioned advantages resulting from the permanent galvanic connection between the spring element and the current-carrying switch housing can also be realized in the switch according to the invention with the help of the spacer element.

[0023] The above-mentioned task is thus completely solved.

[0024] While the spring element rests against the spacer element in the high-temperature position of the switching mechanism, the spring element is preferably spaced from the spacer element in the low-temperature position of the switching mechanism. Thus, the spring element does not touch the spacer element in the low-temperature position of the switch.

[0025] According to one embodiment, the at least one section of the spring element, which is arranged between the spacer element and the switch housing and is fixed in position by an interaction of the spacer element and the switch housing, has an outer edge of the spring element.

[0026] In other words, the spring element is preferably fixed in position at the edge by the interaction of the spacer element and the switch housing. Particularly preferably, the at least one section of the spring element has a radially outer edge of the spring element. This has the advantage of a space-saving, edge-mounted mounting of the spring element, while the central area of ​​the spring element remains freely accessible to the switching mechanism.

[0027] According to a further embodiment, the at least one section of the bimetallic element, which is arranged between the spring element and the spacer element and is supported on the spacer element in the high-temperature position of the switching mechanism, has an outer edge of the bimetallic element.

[0028] In other words, in the high-temperature position of the switching mechanism, the outer edge of the bimetallic element rests against the spacer element. This outer edge is preferably spaced from the spacer element in the low-temperature position of the switching mechanism. This also allows for the most space-saving arrangement of the switching mechanism. Furthermore, the spacer element can be placed on the radially outer edge of the switching mechanism to save space without impairing the other components of the switching mechanism.

[0029] According to a further embodiment, the at least one section of the spring element which is arranged between the spacer element and the switch housing is (i) clamped directly or indirectly between the spacer element and the lower part or (ii) clamped directly or indirectly between the spacer element and the cover part.

[0030] Such a clamping arrangement between the spacer element and the base or between the spacer element and the cover part is particularly easy to implement for securing the position of the spring element. The spring element can thus be simply inserted into the desired location inside the switch housing during assembly, the spacer element placed on top or underneath, and the switch housing then closed by attaching the cover part to the base or vice versa. The position of the spring element is then automatically secured as soon as the cover part is attached to the base. This does not require any additional effort during the assembly process.

[0031] In this case, "indirectly clamped" means that the spring element is clamped by the spacer element and the base part, or by the spacer element and the cover part together, but it does not necessarily have to be directly in contact with these two components. Additional housing components or elements can be arranged between them. In particular, an insulating film or other intermediate layer can be arranged between the aforementioned components.

[0032] According to a further embodiment, the spacer element has a spacer ring.

[0033] Particularly preferably, the spacer element is designed as a spacer ring. The spacer element can therefore be designed as a standard component. Additional costs are minimal, if any, resulting from the provision of the spacer element. The spacer element itself can be made of an electrically conductive material (e.g., metal) or an electrically non-conductive material (e.g., plastic).

[0034] According to a further embodiment, the spacer element has a substantially L-shaped cross-section.

[0035] A "substantially L-shaped cross-section" means that the cross-sectional area of ​​the spacer element has a shape that is at least similar to an L-shape. Preferably, the shape of the cross-sectional area corresponds to an L-shape.

[0036] According to a further embodiment, a first side of the spring element facing the bimetallic element faces the contact surface.

[0037] The bimetallic element is therefore arranged on the same side of the spring element as the contact surface of the stationary counter-contact. If the contact surface of the stationary counter-contact is arranged above the spring element, the bimetallic element is also arranged above the spring element. If, however, the contact surface of the stationary counter-contact is arranged below the spring element, the bimetallic element is also arranged below the spring element. This has the advantage that the bimetallic element and the spring element can be curved in the same direction both in the low-temperature position of the switching mechanism and in the high-temperature position of the switching mechanism.In the high-temperature position of the switching mechanism, the bimetallic element can, for example, press with its center directly against a central area of ​​the spring element in order to lift the movable contact part from the contact surface of the stationary counter contact.

[0038] According to a further embodiment, the spacer element protrudes in a first direction from the first side of the spring element and has a support surface on which the at least one section of the bimetallic element is supported in the high-temperature position of the switching mechanism, wherein the support surface is oriented transversely, preferably orthogonally, to the first direction.

[0039] The term "transverse" does not necessarily refer to an orthogonal or vertical alignment. Instead, it refers to any type of alignment that is not parallel. Thus, an oblique alignment at an angle other than 0° also falls under the term "transverse."

[0040] In the low-temperature position of the switching mechanism, at least one section of the bimetallic element is preferably spaced from the support surface.

[0041] Due to the described, essentially L-shaped cross-section of the spacer element, it can easily function as a kind of retaining claw, against which the bimetallic element can rest on the edge in the high-temperature position of the switchgear. At the same time, the spacer element preferably rests flat on the spring element and acts as a hold-down device for the spring element, securing the spring element in its position within the switch housing.

[0042] According to a further embodiment, the spacer element is clamped in the switch housing by an interaction of the lower part and the cover part.

[0043] This has the advantage that the spacer element is automatically fixed in its position after the switch housing is closed. Likewise, at least one section of the spring element is automatically fixed in its position after the switch housing is closed. The spacer element can be clamped directly or indirectly between the lower part and the cover part. If both the lower part and the cover part as well as the spacer element are made of an electrically conductive material, an insulating element, preferably in the form of an insulating film, is arranged at least between the spacer element and the lower part or between the spacer element and the cover part.

[0044] According to a further embodiment, the spring element has at least one compensating section between its outer edge and an inner region, which is resilient in the radial direction and enables a mechanical deformation of the spring element.

[0045] The at least one compensation section has the advantage of compensating for or at least reducing internal deformations that can occur due to the edge clamping of the spring element during switching of the switching mechanism. Such internal deformations and the resulting internal forces would otherwise lead to mechanical stress and aging of the spring element, which would limit the service life of the switches equipped with them.

[0046] In this context, such a "compensating section" is understood to be a region of the spring element that is designed to be yielding or resilient in the radial direction and allows for radial deflection or expansion within the spring element, even though the outer edge of the spring element is firmly clamped and therefore cannot move radially, or at least only very slightly. A compensating section can therefore also be referred to as an expansion structure.

[0047] According to a further embodiment, the movable contact part is firmly attached to the spring element.

[0048] For example, the movable contact part is soldered or welded to the spring element. This allows for simple and cost-effective assembly of the derailleur because the contact part cannot slip during assembly. Preferably, the movable contact part is located in a central, middle area of ​​the spring element.

[0049] According to a further embodiment, the bimetal element is held captive, but with play, on the movable contact part (and the spring element).

[0050] The spring element, the bimetallic element, and the movable contact part thus form a single unit, allowing the switching mechanism to be assembled and temporarily stored as a separate semi-finished part. Separate testing of the switching mechanism is also possible, as the bimetallic element is held captive, but with play, and thus loosely, to the movable contact part, allowing it to deform freely between its low-temperature and high-temperature configurations.

[0051] According to a further embodiment, the bimetallic element and the spring element are each substantially disc-shaped, and the movable contact part is centrally attached to the spring element. Particularly preferably, both the spring element and the bimetallic element are each circular disc-shaped.

[0052] According to a further embodiment, the first electrical external connection of the switch is arranged on the outside of the cover part and the second electrical external connection of the switch is arranged on the outside of the lower part.

[0053] This ensures easy electrical connection of the temperature-dependent switch.

[0054] According to a further embodiment, the lower part has a free upper edge which is flanged or bent over onto the cover part.

[0055] This results in the simplest and most stable type of fastening between the lower part and the cover part, as is known, for example, from DE 10 2013 109 291 A1.

[0056] It is understood that the features mentioned above and those to be explained below can be used not only in their respective specified combinations, but also in other combinations or on their own, without departing from the scope of the present invention.

[0057] 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 switch according to a first embodiment, wherein the switch is in its low-temperature position; Fig. 2 is a schematic sectional view of the Fig. 1 shown temperature-dependent switch, wherein the switch is in its high-temperature position; Fig. 3 is a schematic sectional view of the temperature-dependent switch according to a second exemplary embodiment, wherein the switch is in its low-temperature position; Fig. 4 is a schematic sectional view of the temperature-dependent switch according to a third exemplary embodiment, wherein the switch is in its low-temperature position; Fig. 5 is a schematic sectional view of the temperature-dependent switch according to a fourth exemplary embodiment, wherein the switch is in its low-temperature position; and Fig. 6 is a schematic sectional view of the temperature-dependent switch according to a fifth exemplary embodiment, wherein the switch is in its low-temperature position.

[0058] Fig. 1-6 show five different embodiments of the switch according to the invention, each in a schematic sectional view. The switch is designated in its entirety by reference numeral 10.

[0059] The switch 10 is rotationally symmetrical and has a circular shape when viewed from above. The switch 10 has a switch housing 12 in which a temperature-dependent switching mechanism 14 is arranged. The switch housing 12 comprises a pot-shaped lower part 16, which is closed by a cover part 18. The lower part 16 has an upstanding edge 20, which is bent or flanged inward in the region of its free upper end, thereby clamping or fixing the cover part 18 to the lower part 16 with an insulating film 22 interposed.

[0060] The lower part 16 and the cover part 18 are made of an electrically conductive material, preferably metal. In the presently shown embodiment, the lower part 16 is a deep-drawn steel housing, which results in comparatively high pressure resistance. The insulating film 22 is arranged between the lower part 16 and the cover part 18, which serves to electrically insulate the two switch housing components 16, 18.

[0061] The cover part 18 completely closes the lower part 16. In addition to providing electrical insulation, the insulating film 22 also provides a sufficient mechanical seal between the lower part 16 and the cover part 18, sealing the interior of the switch housing 12 from the outside. This prevents liquids or contaminants from entering the housing interior.

[0062] The switching mechanism 14, located inside the switch housing, has a temperature-independent spring element 24 and a temperature-dependent bimetallic element 26. The spring element 24 is preferably designed as a circular disk-shaped spring snap-action disc.

[0063] The temperature-dependent bimetallic element 26 is preferably designed as a bimetallic disc, which has two temperature-dependent configurations, a geometric low-temperature configuration (see Fig. 1 ) and a high-temperature geometric configuration (see Fig. 2 ). In the area of ​​the center 28 of the spring element 24, a contact part 30 is attached to the spring element 24. This contact part 30 is integrally connected to the spring element 24. For example, the contact part 30 is welded or soldered to the spring element 24. Since the contact part 30 moves together with the spring element 24 relative to the switch housing 12 during a switching operation, the contact part 30 is also referred to as a "movable contact part."

[0064] The bimetallic element 26 is held captive, but with some play, on the movable contact part 30. A through-hole 32 provided centrally in the bimetallic element 26 has an inner diameter that is slightly larger than an outer diameter of the movable contact part 30, which is pronounced in the lower region. However, since the outer diameter of the movable contact part 30 in its upper region is larger than this inner diameter of the through-hole 32 and the spring element 24 is arranged below the bimetallic element 26 and is firmly connected to the movable contact part 30, the bimetallic element 26 cannot accidentally detach from the switching mechanism 14 despite its freedom of movement. The spring element 24, the bimetallic element 26, and the movable contact part 30 thus represent a captive unit of the switching mechanism 14, which can be pre-produced as a semi-finished product and can be inserted as a whole into the switch housing 12 during assembly of the switch 10.

[0065] In the Fig. 1 In the low-temperature position of the switching mechanism 14 shown, the spring element 24 presses the movable contact part 30 against a contact surface 34 which is arranged on the underside of a stationary contact part 36. The stationary contact part 36 is in the Fig. 1 shown embodiment is arranged on an underside 38 of the cover part 18 facing the lower part 16.

[0066] In the area of ​​its radially outer outer edge 40, the spring element 24 is fixed in the switch housing 12. More precisely, a radially outer section 42, which forms the outer edge 40 of the spring element 24, is in the Fig. 1 In the embodiment shown, the spring element 24 is clamped between a spacer element 44 and the lower part 16 of the switch housing 12. The spacer element 44 is in turn also clamped in the switch housing 12 between the lower part 16 and the cover part 18. The spacer element 44 is clamped indirectly between the lower part 16 and the cover part 18 and is arranged directly between the spring element 24 and the insulating film 22.

[0067] When assembling the Fig. 1 In the switch 10 shown, the switching mechanism 14 is first inserted into the lower part 16. Subsequently, the spacer element 44 is placed on the outer edge section 42 of the spring element 24 and then the cover part is placed on the spacer element 44 with the insulating film 22 interposed. Finally, the upper, upstanding edge 20 of the lower part is bent or flanged inwards, whereby the cover part 18 is pressed from above onto the spacer element 44, which in turn presses onto the spring element 24, whereby the spring element 24 is fixed in position in the switch housing 12. It is understood that the positional fixation only affects the outer edge section 42 of the spring element 24, but the central region 28 of the spring element 24 together with the movable contact part 30 is still movable within the switch housing 12.

[0068] The spacer element 44 is designed as a spacer ring having a substantially L-shaped cross-section. This spacer ring 44 is in a first direction, which here corresponds to the vertical direction and in Fig. 1 schematically indicated by the arrow 46, from a first side 48 of the spring element 24. This first side 48 of the spring element 24 is the (top) side of the spring element 24, which faces the bimetallic element 26 and the contact surface 34.

[0069] The spacer element 44 further has a support surface 50 which is oriented transversely to the first direction 46 and faces the bimetal element 26.

[0070] An outer section 52, which has an outer edge 54 of the bimetallic element 26, is arranged between the spring element 24 and the spacer element 44. More precisely, this section 52 of the bimetallic element 26 is arranged between the support surface 50 and the spring element 24. With this outer section 52, the bimetallic element 26 is supported in the high-temperature position of the switching mechanism 14 on the spacer element 44 or on the support surface 50 arranged thereon (see Fig. 2 ).

[0071] In the Fig. 1 In the closed switching position of the switch 10 shown in FIG. 1, in which the switching mechanism 14 is in its low-temperature position, the spring element 26 presses the movable contact part 30 against the contact surface 34 arranged on the stationary contact part 36. Since the spring element 24 with its outer edge section 42 is in permanent galvanic contact with the lower part 16, the switching mechanism 14 is thus in the Fig. 1 shown low-temperature position, an electrically conductive connection is established between a first external terminal 56 and a second external terminal 58. The first external terminal 56 functions here, for example, the outside of the cover part 18. If the cover part 18 is not made entirely of metal, only a part of it can be made of metal or an electrically conductive material, wherein this part is connected to the stationary contact part 36 and is led to the outside. For example, a through-contact can be arranged in the cover part 18 above the stationary contact part 36, as is known, for example, from DE 103 01 803 B4. The second external terminal 58 functions in the case of the Fig. 1 shown switch 10 preferably an outer side of the lower part 16.

[0072] In the low-temperature position of the switch 10, an electrical current can thus flow from the first external terminal 56 through the cover part 18 into the stationary contact part 36 and from there via the movable contact part 30, the spring element 24 into the base part 16, and thus finally to the second external terminal 58 (or vice versa). In this low-temperature position of the switch 10, the bimetallic element 26 is mounted more or less force-free.

[0073] Now increases starting from the Fig. 1 If, in the situation shown, the temperature of the device to be monitored by the switch 10 and thus also the temperature of the switch 10 and the switching mechanism 14 used therein exceeds a response temperature of the bimetallic element 26, the bimetallic element 26 snaps out of its Fig. 1 shown low-temperature configuration into its Fig. 2 shown high-temperature configuration. The top side of the bimetallic element 26 snaps from a convex curvature into a concave curvature. The bimetallic element 26 then rests with its outer edge section 52 from below on the support surface 50 of the spacer element 44. At the same time, the bimetallic element 26 presses the movable contact part 30 downwards with its center and lifts it off the contact surface 34. During this switching movement, the bimetallic element 26 exerts a force that counteracts the force exerted by the spring element 24 on the contact part 30 in the low-temperature position. As a result, the spring element 24 also snaps from its Fig. 1 shown first convex shape on the top into its Fig. 2 shown concave shape on the top.

[0074] This interrupts the current flow through switch 10. The switch is then open.

[0075] In order to give the spring element 24 the opportunity to move out of the position in Fig. 1 shown situation in the Fig. 2 In order to be able to mechanically expand the spring element 24 despite its edge-side clamping in the situation shown, the spring element 24 preferably has a plurality of compensating sections 60. These compensating sections 60 enable expansion and compression of the spring element 24 in the radial direction, thereby avoiding, in particular, internal stresses or deformations of the spring element 24. The compensating sections 60 can be designed similarly to that disclosed in DE 10 2013 109 291 A1.

[0076] A further advantage of the fixed clamping of the outer edge 40 of the spring element 24 is that, due to the permanent mechanical and electrical connection between the spring element 24 and the switch housing 12, sparks and / or arcs cannot form during a switching operation, as is often the case with switchgear in which the spring element lifts away from the switch housing at the edge during the switching operation. This effectively prevents contact erosion.

[0077] Fig. 3 shows a second embodiment of the switch 10 in a schematic sectional view. Here, too, the low-temperature position of the switch 10 is shown, in which the switching mechanism 14 establishes the electrically conductive connection between the first external terminal 56 and the second external terminal 58. The switching mechanism 14 is fundamentally constructed in the same way as in the first embodiment. However, it is rotated by 180°, so to speak, inserted "upside down" into the switch housing 12.

[0078] The spring element 24 is clamped with its edge portion 42 between the cover part 18 and the spacer element 44. The spacer element 44 is in turn clamped in the switch housing 12 between the lower part 16 and the cover part 18, whereby according to this second embodiment, it is now clamped between the spring element 24 and the lower part 16 with the insulating film 22 interposed.

[0079] The spacer element 44, in turn, has a substantially L-shaped cross-section and has a support surface 50 against which the bimetallic element 26, in its high-temperature configuration, can be supported with its outer edge portion 52. Here, too, the first side 48 of the spring element 24 faces both the bimetallic element 26 and the contact surface 34. However, the first side 48 of the spring element 24 points downward here. However, according to this exemplary embodiment, the stationary contact part 36 with the contact surface 34 arranged thereon is no longer arranged on the cover part 18, but rather on the lower part 16.

[0080] However, the general switching behavior of the switching mechanism 14 does not change, which is why the high temperature position of the switch 10 leads to the Fig. 3 shown second embodiment is not shown again separately for the sake of simplicity.

[0081] Fig. 4 shows a third embodiment of the switch 10 according to the invention, wherein the switch 10 is basically constructed similarly to that in Fig. 1 and 2shown first embodiment. The spring element 24 is again clamped with its outer edge section 42 between the spacer element 44 and the lower part 16 of the switch housing 12. The switching mechanism 14, however, is constructed somewhat differently. Here too, the first side 48 of the spring element 24 faces the bimetallic element 26 as well as the contact surface 34. However, the bimetallic element 26 rests here from above on a circumferential collar 62 provided on the movable contact part 30. The spring element 24 rests against this collar 62 from the opposite lower side. The movable contact part 30 is not necessarily materially connected to the spring element 24 here. Instead, the spring element 24 has a central through-opening 64 into which the part of the movable contact part 30 located below the collar 62 is positively inserted.

[0082] Another difference to the Fig. 1 and 2The first embodiment shown is that the stationary contact part 36 is not arranged on the underside 38 of the cover part 18. Instead, in the embodiment shown in Fig. 4 In the third embodiment shown, a contact carrier element 66 is arranged in the switch housing 12, to which the stationary contact part 36 is fastened. The contact carrier element 66 functions as a type of lower cover, which is clamped between the lower part 16 and the cover part 18. More precisely, the edge 68 of this contact carrier element 66 is clamped between the cover part 18 and the spacer element 44 with the insulating film 22 interposed.

[0083] The contact carrier element 66 is preferably made of an electrically conductive material, for example, metal. The contact carrier element 66 particularly preferably has a thinner wall thickness than the cover part 18 of the switch housing 12 arranged above it.

[0084] The key advantage of the additional contact carrier element 66 provided here is that it allows manufacturing tolerances on the switch housing 12 and the switching mechanism 14 to be compensated for in a simple design. Depending on the customer's requirements, the contact carrier element 66, designed as a lower cover, can be preformed to achieve a desired contact pressure in the low-temperature position of the switching mechanism 14. For example, if a high contact pressure between the stationary contact part 36 and the movable contact part 30 is desired while a high performance capability of the switch 10 is required, a differently shaped contact carrier element 66 can be inserted into the switch housing 12 than if lower performance capabilities of the switch are required.In other words, the contact pressure between the switching mechanism 14 and the stationary contact part 36 can be very easily adjusted using the contact carrier element 66, without the switch housing 12 itself having to be modified. It goes without saying that adjusting the respective contact pressure automatically also results in a corresponding adjustment of the contact resistance between the switching mechanism 14 and the stationary contact part 36. The fact that this adjustment can be determined more or less solely by the shape of the contact carrier element 66 offers an enormous cost advantage, since switches can thus be adapted to a wide variety of technical specifications without having to change anything on the switching mechanism 14 or the switch housing 12.

[0085] Also in Fig. 5 The fourth embodiment of the switch 10 according to the invention shown follows this principle. Unlike in the Fig. 4 In the embodiment shown, only the contact surface 34 is arranged directly on the underside of the contact carrier element 66. An extra stationary contact part 36 is omitted.

[0086] Also in Fig. 6 The fifth embodiment shown follows the aforementioned principle. Here, however, the contact carrier element 66 is designed as a second spring element 70, to which the contact part 36, together with its contact surface 34 arranged thereon, is fastened. This second spring element 70 allows the contact pressure between the movable contact part 30 and the contact surface 34 to be increased even further, thereby further reducing the contact resistance between these two components. The second spring element 70 exerts a force on the contact part 36 that is opposite to the force exerted by the first spring element 24 on the movable contact part 30.

[0087] Finally, the Fig. 4-6 shown embodiments that the second external connection 58 of the switch is designed somewhat differently here than according to the embodiment shown in Fig. 1-3 shown embodiments. The external connection 58 is designed here as a recess provided in the lower part 16, into which a circumferential connection ring 72 can be inserted, which is preferably welded to the lower part 16. This connection ring 58 can not only function as an electrical connection, but can also be connected to the conveyor belt during the manufacture of the switch 10.

Claims

1. Temperature-dependent switch (10), comprising: - a switch housing (12) with a lower part (16) and a cover part (18) closing the lower part (16);- a temperature-dependent switching mechanism (14) which is arranged in the switch housing (12) and has a movable contact part (30), a bimetallic element (26) and a spring element (24) which interacts with the movable contact part (30), wherein the switching mechanism (14) is designed to switch in a temperature-dependent manner between a low-temperature position, in which it presses the movable contact part (30) against a contact surface (34) arranged in the interior of the switch housing (12) and thus establishes an electrical connection between a first electrical external terminal (56) of the switch (10) and a second electrical external terminal (58) of the switch (10), and a high-temperature position, in which it keeps the movable contact part (30) spaced from the contact surface (34) and thus interrupts the electrical connection between the first electrical external terminal (56) and the second electrical external terminal (58);and - a spacer element (44) which is arranged in the interior of the switch housing (12) between the lower part (16) and the cover part (18); wherein at least one section (42) of the spring element (24) is arranged between the spacer element (44) and the switch housing (12) and is fixed in position by an interaction of the spacer element (44) and the switch housing (12), and wherein at least one section (52) of the bimetallic element (26) is arranged between the spring element (24) and the spacer element (44) and is supported on the spacer element (44) in the high-temperature position of the switching mechanism (14).

2. Temperature-dependent switch according to claim 1, wherein the at least one portion (42) of the spring element (24) arranged between the spacer element (44) and the switch housing (12) has an outer edge (40) of the spring element (24).

3. Temperature-dependent switch according to claim 1 or 2, wherein the at least one portion (52) of the bimetallic element (26) arranged between the spring element (24) and the spacer element (44) has an outer edge (54) of the bimetallic element (26).

4. Temperature-dependent switch according to one of claims 1-3, wherein the at least one section (42) of the spring element (24) which is arranged between the spacer element (44) and the switch housing (12) is (i) clamped directly or indirectly between the spacer element (44) and the lower part (16) or (ii) clamped directly or indirectly between the spacer element (44) and the cover part (18).

5. Temperature-dependent switch according to one of claims 1-4, wherein the spacer element (44) comprises a spacer ring.

6. Temperature-dependent switch according to one of claims 1-5, wherein the spacer element (44) has a substantially L-shaped cross-section.

7. Temperature-dependent switch according to one of claims 1-6, wherein a first side (48) of the spring element (24) facing the bimetallic element (26) faces the contact surface (34).

8. Temperature-dependent switch according to claim 7, wherein the spacer element (44) protrudes in a first direction (46) from the first side (48) of the spring element (24) and has a support surface (50) on which the at least one section (52) of the bimetallic element (26) is supported in the high-temperature position of the switching mechanism (14), wherein the support surface (50) is oriented transversely, preferably orthogonally, to the first direction (46).

9. Temperature-dependent switch according to one of claims 1-8, wherein the spacer element (44) is clamped in the switch housing (12) by an interaction of the lower part (16) and the cover part (18).

10. Temperature-dependent switch according to one of claims 1-9, wherein the spring element (24) has at least one compensating section (60) between an outer edge (54) and an inner region (28), which is resilient in the radial direction and enables mechanical deformation of the spring element (24).

11. Temperature-dependent switch according to one of claims 1-10, wherein the movable contact part (30) is firmly attached to the spring element (24).

12. Temperature-dependent switch according to one of claims 1-11, wherein the bimetallic element (26) is held captively but with play on the movable contact part (30).

13. Temperature-dependent switch according to one of claims 1-12, wherein the bimetallic element (26) and the spring element (24) are each substantially disc-shaped and the movable contact part (30) is centrally attached to the spring element (24).

14. Temperature-dependent switch according to one of claims 1-13, wherein the first external electrical connection (56) is arranged on the outside of the cover part (18) and the second external electrical connection (58) is arranged on the outside of the base part (16).

15. Temperature-dependent switch according to one of claims 1-14, wherein the lower part (16) has a free, upper edge (20) which is flanged or bent over onto the cover part (18).