TEMPERATURE-CONTROLLING SWITCH

Description

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

[0002] Temperature-dependent switches are already known in a large number of forms. Examples of temperature-dependent switches are disclosed in DE 10 2013 109 291 A1 and DE 10 2011 119 637 B4. EP 2 874 171 A1 discloses a temperature-dependent switch according to the preamble of claim 1.

[0003] Such temperature-dependent switches serve, in a manner known per se, 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 with the supply circuit of the device to be protected via connecting leads, so that below the switch's response temperature, 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 against the outside. The switch housing has a two-part construction. It comprises a lower part that 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 rim, the free upper edge of which is bent or crimped over onto the cover part.

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

[0007] The temperature-dependent switching behavior of the switching mechanism is primarily due to a temperature-dependent bimetallic element, which, in the switches known from DE 10 2013 109 291 A1 and DE 10 2011 119 637 B4, is designed in a disc-like form and is often also referred to as a bimetallic snap disc. This bimetallic element is usually designed as a multi-layered, active, sheet-like component consisting of two, three, or four interconnected components with different coefficients of thermal expansion. The connection between the individual layers of metals or metal alloys in such bimetallic elements is usually material-bonded or form-fitted 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. The bimetallic element switches from its low-temperature configuration to its high-temperature configuration depending on the temperature, following a hysteresis pattern.

[0009] If the temperature of the bimetallic element rises above its response temperature due to a temperature increase in the device being protected, the element switches from its low-temperature configuration to its high-temperature configuration. In this process, the bimetallic element works against the spring element, lifting the movable contact part away from the stationary contact, thus opening the switch and disconnecting the device being protected, preventing it from heating up further.

[0010] Unless a reset lock is provided, the bimetallic element snaps back into its low-temperature configuration, so that the switch closes again as soon as the temperature of the bimetallic element drops below the so-called reset temperature of the bimetallic 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 stress, and is 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, does not change 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 disc, is in permanent contact with the lower part in the region of its outer edge. In the switch from DE 10 2011 119 637 B4, part of the outer edge of the spring-loaded snap disc is metallurgically bonded to the lower part of the switch housing. In the switch from DE 10 2013 109 291 A1, the spring-loaded snap 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, and thus mechanically fixed. In both cases, the spring-loaded snap disc is therefore permanently galvanically connected to the current-carrying switch housing in both the low-temperature and high-temperature positions of the switching mechanism.

[0013] The permanent galvanic connection between the spring-loaded snap disc and the current-carrying lower part of the switch housing ensures that the contact resistance between the spring-loaded snap disc and the lower part of the switch housing is very low in the aforementioned switches. This eliminates a potential source of error that can occur during the final continuity test of a fully assembled temperature-dependent switch. It is possible that, due to manufacturing tolerances, the contact resistance between the lower part of the housing and the spring-loaded snap disc could be so high that the finished temperature-dependent switch would have to be rejected.

[0014] Conversely, most switches known from the prior art are equipped with spring elements whose edges rest loosely, i.e., freely, on the inner base of the lower part of the switch housing or on a shoulder encircling the inside of the lower part. Such a switch is known, for example, from DE 43 45 350 A1. It is understood that such a loosely resting spring element has significantly 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 generally has a positive effect on the service life of the switching mechanism and the long-term stability of its switching temperature. However, the lack of a permanent galvanic connection between the spring element and the current-carrying switch housing, which is not provided for here, results in the aforementioned disadvantages, i.e.,in particular an increased rejection rate and an increased transition resistance.

[0015] Against this background, the present invention aims to provide 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 objective 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 problem is solved by a temperature-dependent switch according to claim 1, which comprises the following components: a switch housing with a lower part and a cover part closing the lower part; a temperature-dependent switching mechanism arranged in the switch housing and comprising 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 between a low-temperature position, in which it presses the movable contact part against a contact surface arranged inside the switch housing and thereby 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 away from the contact surface and thereby interrupts the electrical connection between the first electrical external terminal and the second electrical external terminal;and a spacer element which is arranged inside the switch housing between the lower part and the cover part; ; wherein at least one section of the spring element 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, and wherein at least one section 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 an interaction between 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, is possible, but not necessarily required. The switch housing and the spacer element can each also be indirectly connected to the spring element.

[0018] Unlike the switch known from DE 10 2013 109 291 A1, 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 lower part and the cover part 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 counter bearing against which the bimetallic element can be supported in the high-temperature position of the switching mechanism.

[0019] Thus, a single component in the form of a spacer element can perform several functions simultaneously. This simplifies not only the switch's design but also its assembly. Furthermore, the switch's additional function as a support for the bimetallic element also positively impacts its lifespan.

[0020] In the switches mentioned 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. Support against the spring element has the disadvantage that it is subjected to significant mechanical stress, especially after many switching cycles, and can be damaged. Support against the cover of the switch housing, on the other hand, is less problematic, but requires, firstly, that the switching mechanism be very precisely matched to the manufacturing tolerances of the housing components, and secondly, that the bimetallic element in its high-temperature configuration usually has to deflect considerably until its outer edge reaches the cover and its center presses the movable contact downwards.

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

[0022] The advantages mentioned above, which result 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 has therefore been completely solved.

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

[0025] According to one embodiment, 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 its edge by the interaction of the spacer element and the switch housing. Particularly preferably, at least one section of the spring element has a radially outer edge. This has the advantage of providing the most space-saving, edge-mounted support for the spring element, while the central area of ​​the spring element remains freely accessible to the switching mechanism.

[0027] According to a further embodiment, 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 bimetallic element rests against the spacer element with its outer edge. In the low-temperature position of the switching mechanism, this outer edge is preferably spaced away from the spacer element. This also allows for a space-saving arrangement of the switching mechanism. Furthermore, the spacer element can be positioned in a space-saving manner at the radially outer edge of the switching mechanism without interfering with the other components of the switching mechanism.

[0029] According to a further embodiment, 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 and the base or between the spacer and the cover is particularly easy for securing the position of the spring element. During switch assembly, the spring element can simply be inserted at the desired location inside the switch housing, the spacer placed on or underneath it, and the switch housing then closed by attaching the cover to the base or vice versa. The spring element is automatically secured in position as soon as the cover is attached to the base. This eliminates any additional effort in the assembly process.

[0031] The term "indirectly clamped" in this context means that the spring element is clamped by the spacer and the lower part or the spacer and the cover part together, but it does not necessarily have to be in direct contact with these two components. Further housing components or elements can be arranged in between. In particular, for example, 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] The spacer element is preferably designed as a spacer ring. Therefore, the spacer element can be a standard component. Providing the spacer element incurs no additional costs, or if any, only minimal ones. 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 an essentially L-shaped cross-section.

[0035] In this context, 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 located on the same side of the spring element as the contact surface of the stationary mating contact. If the contact surface of the stationary mating contact is located above the spring element, then the bimetallic element is also located above the spring element. Conversely, if the contact surface of the stationary mating contact is located below the spring element, then the bimetallic element is also located below the spring element. This has the advantage that the bimetallic element and the spring element can be curved in the same direction in both the low-temperature and high-temperature positions of the switching mechanism.In the high-temperature position of the switching mechanism, the bimetallic element can, for example, press directly against a central area of ​​the spring element with its center 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 projects in a first direction from the first side of the spring element and has a support surface on which 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" in this context does not necessarily refer to an orthogonal or perpendicular orientation. Instead, it encompasses any orientation that is not parallel. Therefore, an oblique orientation 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 away from the support surface.

[0041] Due to the described, essentially L-shaped cross-sectional form of the spacer element, it can very easily function as a kind of retaining claw against which the bimetallic element can be supported at its edge in the high-temperature position of the switching mechanism. At the same time, the spacer element preferably lies flat on the spring element and acts as a retainer for the spring element, thereby fixing 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 position after the switch housing is closed. Likewise, at least one section of the spring element is also automatically fixed in 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 the lower part, the cover part, and the spacer element are all 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 area, which is resilient in the radial direction and allows mechanical deformation of the spring element.

[0045] The at least one compensating 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 mechanism. Such internal deformations, as well as the resulting internal forces, would otherwise lead to mechanical stress and aging of the spring element, thus limiting the service life of the switches equipped with it.

[0046] In this context, such a "compensating section" is understood to be a region of the spring element that is radially flexible or resilient and allows radial movement within the spring element, even though the outer edge of the spring element is rigidly 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 attached to the spring element by a material bond.

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

[0049] According to a further embodiment, the bimetallic element is captive, but held 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 stored as a separate semi-finished component. Separate testing of the switching mechanism is also possible, as the bimetallic element is captive but held with some play (i.e., loosely) on 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 essentially 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 designed in a circular disc shape.

[0052] According to a further embodiment, the first external electrical connection of the switch is arranged on the outside of the cover part and the second external electrical 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 that is folded or bent over onto the lid part.

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

[0056] Exemplary embodiments of the invention are shown in the drawings and are explained in more detail in the following description. They show: Fig. 1 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 a schematic sectional view of the in Fig. 1 Figure 1 shows a temperature-dependent switch in its high-temperature position; Figure 3 shows a schematic sectional view of the temperature-dependent switch according to a second embodiment, in its low-temperature position; Figure 4 shows a schematic sectional view of the temperature-dependent switch according to a third embodiment, in its low-temperature position; Figure 5 shows a schematic sectional view of the temperature-dependent switch according to a fourth embodiment, in its low-temperature position; and Figure 6 shows a schematic sectional view of the temperature-dependent switch according to a fifth embodiment, in its low-temperature position.

[0057] Fig. 1-6 Figure 1 shows five different embodiments of the switch according to the invention, each in a schematic sectional view. The switch is designated in its entirety by the reference numeral 10 in each figure.

[0058] The switch 10 is rotationally symmetrical and, viewed from above, has a circular shape. The switch 10 has a switch housing 12 in which a temperature-dependent switching mechanism 14 is arranged. The switch housing 12 comprises a cup-shaped lower part 16, which is closed by a cover part 18. The lower part 16 has a raised rim 20, which is bent or crimped inwards at its free upper end, thereby clamping or fixing the cover part 18 to the lower part 16 with an insulating film 22 in between.

[0059] The lower part 16 and the cover part 18 are made of an electrically conductive material, preferably metal. In the embodiment shown here, the lower part 16 is a deep-drawn steel housing, which results in a comparatively high pressure resistance. The insulating film 22 is arranged between the lower part 16 and the cover part 18, serving to electrically insulate the two switch housing components 16 and 18.

[0060] The cover part 18 completely seals the base part 16. In addition to electrical insulation, the insulating film 22 also provides sufficient mechanical insulation between the base part 16 and the cover part 18, thus sealing the interior of the switch housing 12 from the outside. This prevents liquids or contaminants from entering the housing interior.

[0061] The switching mechanism 14, located inside the switch housing, comprises a temperature-independent spring element 24 and a temperature-dependent bimetallic element 26. The spring element 24 is preferably designed as a circular spring snap disc.

[0062] The temperature-dependent bimetallic element 26 is preferably designed as a bimetallic disk which has two temperature-dependent configurations, a low-temperature geometric 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 metallurgically bonded 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 along 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".

[0063] The bimetallic element 26 is captive but held with some play on the movable contact part 30. A through-hole 32, centrally located in the bimetallic element 26, has an inner diameter that is slightly larger than the outer diameter of the movable contact part 30, which is pronounced in its lower region. However, since the outer diameter of the movable contact part 30 is larger in its upper region than this inner diameter of the through-hole 32, and since the spring element 24 is located below the bimetallic element 26 and is firmly connected to the movable contact part 30, the bimetallic element 26 cannot unintentionally 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 constitute a captive unit of the switching mechanism 14, which can be pre-produced as a semi-finished product and inserted as a whole into the switch housing 12 during assembly of the switch 10.

[0064] 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 located in the Fig. 1 in the illustrated embodiment on a lower surface 38 of the lid part 18 facing the lower part 16.

[0065] The spring element 24 is fixed in the switch housing 12 in the region of its radially outer edge 40. More precisely, a radially outer section 42, which forms the outer edge 40 of the spring element 24, is fixed in the switch housing 12. Fig. 1 In the illustrated embodiment, the spacer element 44 is clamped between the lower part 16 of the switch housing 12. The spacer element 44 is itself also clamped in the switch housing 12 between the lower part 16 and the cover part 18. The spacer element 44 is indirectly clamped between the lower part 16 and the cover part 18 and directly between the spring element 24 and the insulating film 22.

[0066] During the assembly of the in Fig. 1 In the switch 10 shown, the switching mechanism 14 is first inserted into the lower part 16. Next, 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, raised edge 20 of the lower part is bent or crimped inwards, causing the cover part 18 to press down onto the spacer element 44 from above. This, in turn, presses down on the spring element 24, thus fixing the spring element 24 in position within the switch housing 12. It should be understood that this fixing only affects the outer edge section 42 of the spring element 24; the central area 28 of the spring element 24, together with the movable contact part 30, remains movable within the switch housing 12.

[0067] The spacer element 44 is designed as a spacer ring having an essentially L-shaped cross-section. This spacer ring 44 is oriented in a first direction, which here corresponds to the vertical direction, and in Fig. 1 As schematically indicated by arrow 46, the first side 48 of the spring element 24 extends from a first side 48. This first side 48 of the spring element 24 is the (upper) side of the spring element 24 that faces the bimetallic element 26 and the contact surface 34.

[0068] The spacer element 44 also has a support surface 50, which is oriented transversely to the first direction 46 and faces the bimetallic element 26.

[0069] 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 against the spacer element 44, or rather against the support surface 50 arranged thereon, in the high-temperature position of the switching mechanism 14 (see figure). Fig. 2 ).

[0070] In the Fig. 1 In the closed switching position of the switch 10 shown, 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 is in permanent galvanic contact with the lower part 16 with its outer edge section 42, the switching mechanism 14 thus operates in the position shown. Fig. 1 In the low-temperature position shown, an electrically conductive connection is established between a first external connection 56 and a second external connection 58. The outer surface of the cover part 18 serves as the first external connection 56, for example. If the cover part 18 is not entirely made of metal, only a portion of it can be made of metal or an electrically conductive material, with this portion being connected to the stationary contact part 36 and extending 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 connection 58 in the Fig. 1 The switch 10 shown is preferably located on the outside of the lower part 16.

[0071] In the low-temperature position of the switch 10, an electric 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 lower 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 without force.

[0072] Starting from the point in Fig. 1 In the situation shown, if 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 inserted therein, exceeds a response temperature of the bimetallic element 26, the bimetallic element 26 snaps out of its position. Fig. 1 shown low-temperature configuration in its Fig. 2 The high-temperature configuration shown is transformed. The top surface of the bimetallic element 26 snaps from a convex curvature to a concave curvature. The bimetallic element 26 then rests against the support surface 50 of the spacer element 44 from below with its outer edge section 52. Simultaneously, the bimetallic element 26, with its center, pushes the movable contact part 30 downwards and lifts it from the contact surface 34. During this switching movement, the bimetallic element 26 exerts a force that acts opposite to the force exerted on the contact part 30 by the spring element 24 in the low-temperature position. This also causes the spring element 24 to snap from its position in Fig. 1 shown first convex shape on the upper side in its in Fig. 2 The concave shape shown on the top side is...

[0073] This interrupts the current flow through switch 10. The switch is now open.

[0074] To allow the spring element 24 to move out of the position at the moment of snapping, Fig. 1 the situation shown in Fig. 2 To enable the spring element 24 to expand mechanically despite its edge clamping, as shown, it preferably has several compensating sections 60. These compensating sections 60 allow the spring element 24 to expand and compress in the radial direction, thereby preventing 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.

[0075] 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 switching devices where the spring element lifts away from the switch housing at its edge during the switching operation. This effectively prevents contact erosion.

[0076] Fig. 3 Figure 1 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 the same as in the first embodiment. However, it is rotated by 180°, so to speak, "upside down," and inserted into the switch housing 12.

[0077] The spring element 24 is clamped with its edge section 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, wherein, 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.

[0078] The spacer element 44 has a substantially L-shaped cross-section and a support surface 50 against which the bimetallic element 26, in its high-temperature configuration, can rest with its outer edge section 52. The first side 48 of the spring element 24 again faces both the bimetallic element 26 and the contact surface 34. However, in this embodiment, the first side 48 of the spring element 24 points downwards. According to this embodiment, the stationary contact part 36 with the contact surface 34 attached to it is no longer located on the cover part 18, but rather on the lower part 16.

[0079] However, the general switching behavior of the switching mechanism 14 does not change, which is why the high-temperature position of the switch 10 corresponds to the one in Fig. 3 The second embodiment shown is not shown again separately for the sake of simplicity.

[0080] Fig. 4 Figure 1 shows a third embodiment of the switch 10 according to the invention, wherein the switch 10 is fundamentally constructed similarly to the one in Figure 1. Fig. 1 and 2In the first embodiment shown, 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. However, the switching mechanism 14 is constructed somewhat differently. While the first side 48 of the spring element 24 also faces the bimetallic element 26 and the contact surface 34, the bimetallic element 26 rests 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 bonded to the spring element 24. 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 engaged.

[0081] Another difference from the one in Fig. 1 and 2The difference in the first embodiment shown is that the stationary contact part 36 is not arranged on the underside 38 of the cover part 18. Instead, it is located in the 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 attached. The contact carrier element 66 acts as a kind of bottom cover, which is clamped between the bottom 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.

[0082] The contact carrier element 66 is preferably made of an electrically conductive material, for example, metal. Particularly preferably, the contact carrier element 66 has a thinner wall thickness than the cover part 18 of the switch housing 12 arranged above it.

[0083] The key advantage of the additional contact carrier element 66 provided here is that it allows manufacturing tolerances in the switch housing 12 and the switching mechanism 14 to be compensated for in a simple design manner. Depending on customer requirements, the contact carrier element 66, designed as a bottom cover, can be pre-formed to achieve the 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 required when high performance of the switch 10 is necessary, a differently shaped contact carrier element 66 can be inserted into the switch housing 12 than if lower performance of the switch is required.In other words, the contact pressure between the switching mechanism 14 and the stationary contact part 36 can be easily adjusted using the contact carrier element 66, without requiring any modification to the switch housing 12 itself. It follows that adjusting the contact pressure automatically 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 a significant cost advantage, as switches can thus be adapted to a wide variety of technical specifications without having to modify the switching mechanism 14 or the switch housing 12.

[0084] Even the one in Fig. 5 The fourth embodiment of the switch 10 according to the invention, as shown, follows this principle. Unlike the one in Fig. 4 In the illustrated embodiment, 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.

[0085] Even the one in Fig. 6 The fifth embodiment shown follows the principle mentioned above. 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, is attached. 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 reducing the contact resistance between these two components even more. The second spring element 70 exerts a force on the contact part 36 that opposes the force exerted by the first spring element 24 on the movable contact part 30.

[0086] Finally, regarding the in Fig. 4-6 In the illustrated embodiments, it should also be mentioned that the second external connection 58 of the switch is designed somewhat differently here than according to the one shown in Fig. 1-3 The embodiments shown. The external connection 58 is designed here as a recess provided in the lower part 16, into which a circumferential connecting ring 72 can be inserted, which is preferably welded to the lower part 16. This connecting 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. A temperature-dependent switch (10) comprising: - a switch housing (12) having 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 comprises a movable contact part (30), a bimetal element (26) and a spring element (24) interacting with the movable contact part (30), wherein the switching mechanism (14) is configured to switch in a temperature-dependent manner between a low-temperature state, in which the switching mechanism (14) presses the movable contact part (30) against a contact surface (34) arranged inside the switch housing (12) to establish an electrical connection between a first electrical terminal (56) of the switch (10) and a second electrical terminal (58) of the switch (10), and a high-temperature state, in which the switching mechanism (14) keeps the movable contact part (30) spaced apart from the contact surface (34) to interrupt the electrical connection between the first electrical terminal (56) and the second electrical terminal (58); and - a spacer element (44) 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 bimetal element (26) is arranged between the spring element (24) and the spacer element (44), characterized in that the section (52) of the bimetal element (26) is supported on the spacer element (44) in the high-temperature state of the switching mechanism (14).

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

3. The temperature-dependent switch according to claim 1 or 2, wherein the at least one section (52) of the bimetal element (26) arranged between the spring element (24) and the spacer element (44) comprises an outer edge (54) of the bimetal element (26).

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

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

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

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

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

9. The temperature-dependent switch according to any 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. The temperature-dependent switch according to any one of claims 1-9, wherein the spring element (24) comprises between an outer edge (54) and an inner area (28) at least one compensating section (60), which is configured to be resilient in the radial direction and enables mechanical deformation of the spring element (24).

11. The temperature-dependent switch according to any one of claims 1-10, wherein the movable contact part (30) is fixed to the spring element (24) in a material-locking manner.

12. The temperature-dependent switch according to any one of claims 1-11, wherein the bimetal element (26) is held captive but with play on the movable contact part (30).

13. The temperature-dependent switch according to any one of claims 1-12, wherein the bimetal element (26) and the spring element (24) are each substantially disc-shaped and the movable contact part (30) is mounted centrally on the spring element (24).

14. The temperature-dependent switch according to any one of claims 1-13, wherein the first electrical terminal (56) is arranged on an outside of the cover part (18) and the second electrical terminal (58) is arranged on an outside of the lower part (16).

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