Temperature dependent switch

Abstract

The temperature-dependent switch includes: a switch housing having a lower part and a cover part; a temperature-dependent switching mechanism arranged in the switch housing and comprising a movable contact part, a bimetallic element and a spring element, the switching mechanism being configured to switch between a low temperature state in which the switching mechanism presses the contact part against a contact surface arranged inside the switch housing, and a high temperature state in which the switching mechanism presses the contact part against the contact surface arranged inside the switch housing, a switching mechanism disposed between the contact member and the contact surface to establish an electrical connection between the first and second electrical terminals of the switch, the switching mechanism maintaining the contact member spaced apart from the contact surface to interrupt the electrical connection between the first and second electrical terminals; and a spacing element arranged between the lower part and the cover part; at least one portion of the spring element is arranged between the spacer element and the switch housing, and at least one portion of the bimetallic element is arranged between the spring element and the spacer element and is supported on the spacer element in a high-temperature state of the switching mechanism.

Description

Technical Field

[0001] The present invention relates to temperature dependent switches. Background Art

[0002] A large number of temperature-dependent switches are known in principle. Exemplary temperature-dependent switches are disclosed in DE 10 2013 109 291 A1 and DE 10 2011 119 637 B4.

[0003] Such temperature-dependent switches are used in a manner known in principle to monitor the temperature of a device. For this purpose, the switch is in 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 a switching mechanism arranged inside the switch.

[0004] The switch is usually electrically connected in series to the power circuit of the device to be protected via a connecting cable so that the power current of the device to be protected flows through the switch when the response temperature of the switch is lowered.

[0005] In the switch disclosed in DE 10 2013 109 291 A1, the switching mechanism is arranged inside the switch housing. The switch housing is a closed housing in which the switching mechanism is sealed relative to the outside. The switch housing is formed by two parts. It comprises a lower part which is closed by a cover part. The cover part is fixed to the lower part. For this purpose, the lower part comprises a raised circumferential edge, the free upper edge of which is bent or flanged to the cover part.

[0006] The temperature-dependent switching mechanism arranged in the switch housing comprises a spring element, to which the movable contact part is fixed, and a bimetallic element, which interacts with the movable contact part. The spring element presses the movable contact part against a fixed mating contact part arranged on the cover part inside the switch housing. The outer edge of the spring element, which is configured as a flip spring disk, is supported in the lower part of the switch housing, so that the current flows from the lower part through the flip spring disk and the movable contact part into the fixed mating contact part, and from the fixed mating contact part into the cover part.

[0007] The temperature-dependent bimetallic elements in the switches disclosed in DE 10 2013 109 291 A1 and DE 10 2011 119 637 B4 have a disk-shaped design and are generally referred to as bimetallic flip disks, which are essentially responsible for the temperature-dependent switching behavior of the switching mechanism. Such bimetallic elements are generally constructed as multilayer, active, sheet-like devices consisting of two, three or four interconnected components with different thermal expansion coefficients. The connection of the individual metal or metal alloy layers in a bimetallic element of this type is generally a material-locked or positively locked connection and is achieved, for example, by rolling.

[0008] This bimetallic element has a first stable geometric configuration (low temperature configuration) at a low temperature below the response temperature of the bimetallic element, and has a second stable geometric configuration (high temperature configuration) at a high temperature above the response temperature of the bimetallic element. The bimetallic element flips from its low temperature configuration to its high temperature configuration in a hysteresis-dependent manner.

[0009] Thus, if the temperature of the bimetallic element rises above its response temperature due to a temperature rise in the device to be protected, the bimetallic element flips from its low temperature configuration to its high temperature configuration. The bimetallic element thus works against the spring element in such a way that it lifts the movable contact part from the fixed mating contact, so that the switch opens and the device to be protected is turned off and can no longer be heated.

[0010] Unless a reset lock is provided, as the device to be protected cools down, the bimetallic element will flip back to its low temperature configuration as soon as its temperature drops below its so-called reset temperature, causing the switch to close again.

[0011] In its low temperature configuration, the bimetallic element is preferably mounted in a mechanically stress-free manner in the switch housing, wherein the bimetallic element is also not used to carry current. This has the advantage that the bimetallic element has a longer service life and the switching point (i.e. the response temperature or switching temperature of the bimetallic element) does not change even after many switching cycles.

[0012] In the switches disclosed in DE 10 2013 109 291 A1 and DE 10 2011 119 637 B4, the spring element, which is designed as a flip spring disk, is in permanent contact with the lower part in the region of its outer edge. In the switch disclosed in DE 10 2011 119 637 B4, a part of the outer edge of the flip spring disk is connected to the lower part of the switch housing in a material-locked manner. In the switch disclosed in DE 10 2013 109 291 A1, the flip spring disk rests on a circumferential shoulder provided on the lower part and is clamped between the shoulder and the spacing element, which is designed as a spacing ring, and is thus mechanically fixed. Therefore, in both cases, the flip spring disk is permanently electrically connected to the current-carrying switch housing both in the low-temperature state of the switching mechanism and in the high-temperature state of the switching mechanism.

[0013] The permanent electrical connection of the flip spring disk to the current-carrying lower part of the switch housing ensures that the contact resistance between the flip spring disk and the lower part of the switch housing is very low. In this way, a possible source of error that could occur during the final continuity test of the fully assembled temperature-dependent switch is eliminated. Due to manufacturing tolerances, the contact resistance between the lower part of the housing and the flip spring disk can be so high that the finished temperature-dependent switch has to be discarded as scrap.

[0014] In contrast, most switches known from the prior art are provided with a spring element, the edge of which rests loosely (i.e., freely movable) on an inner base of the lower part of the switch housing or on a shoulder extending circumferentially inside the lower part. Such a switch is disclosed, for example, in DE 43 45 350 A1. It is understood that such a loosely supported spring element has significantly greater mechanical freedom, so that the spring element can move more freely within the switch housing when the switching mechanism is flipped from a low temperature state to a high temperature state (and vice versa). This has a fundamental positive effect on the service life of the switching mechanism and the long-term consistency of its switching temperature. However, the permanent electrical connection between the spring element and the current-carrying switch housing, which is not provided here, leads to the above-mentioned disadvantages, namely, in particular, increased scrap and increased contact resistance. Summary of the invention

[0015] The object of the present invention is therefore to provide a temperature-dependent switch in which the above-mentioned disadvantages are prevented or at least minimized in a structurally simple manner. In this respect, a particular object is to provide a switch consisting of as few components as possible, which is easy to install and whose service life and / or switching capacity can be increased compared to the temperature-dependent switches known hitherto.

[0016] According to the invention, this object is solved by a temperature-dependent switch according to claim 1, comprising the following means: - a switch housing having a lower part and a cover part closing the lower part; - a temperature-dependent switching mechanism, which is arranged in the switch housing and comprises a movable contact part, a bimetallic element and a spring element interacting with the movable contact part, wherein the switching mechanism is configured to switch in a temperature-dependent manner between a low-temperature state and a high-temperature state, in which the switching mechanism presses the movable contact part against a contact surface arranged inside the switch housing to establish an electrical connection between a first electrical terminal of the switch and a second electrical terminal of the switch, and in which the switching mechanism keeps the movable contact part spaced apart from the contact surface to interrupt the electrical connection between the first electrical terminal and the second electrical terminal; and - a spacing element, which is 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 spacing element and the switch housing and is fixed in place by the interaction of the spacing element with the switch housing, and Therein, at least a portion of the bimetallic element is arranged between the spring element and the spacing element, and is supported on the spacing element in the high temperature state of the switching mechanism.

[0017] Similar to the switch disclosed in 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 spacing element arranged inside the switch housing. More precisely, the spring element is fixed in its position by the interaction of the spacing element with the switch housing. This means that both the spacing element and the switch housing contribute to fixing the position of the spring element. Both the spacing element and the switch housing exert a force on the spring element, thereby fixing the spring element in place. On the one hand, there can be, but not necessarily, direct contact between the spacing element and the spring element, and on the other hand, there can also be, but not necessarily, direct contact between the switch housing and the spring element. The switch housing and the spacing element can also be indirectly connected to the spring element.

[0018] However, unlike the switch disclosed in DE 10 2013 109 291 A1, the spacing element in the switch according to the invention simultaneously fulfills several functions. It fulfills two known functions, namely it is configured to keep the lower part and the cover part spaced apart from each other, and it is configured to fix the spring element in its position. According to the invention, the spring element additionally fulfills a third function, namely it serves as an abutment against which the bimetallic element can be supported in the high-temperature state of the switching mechanism.

[0019] Thus, with the aid of a single component in the form of a spacer element, several functions can be fulfilled simultaneously. This not only simplifies the structural design of the switch, but also simplifies the assembly of the switch. The latter additional function of the switch as an abutment for the bimetallic element also has a positive effect on the service life of the switch.

[0020] In the above-mentioned switches, the bimetallic element in its hot state is usually supported on the spring element itself or on the cover part of the switch housing. Supporting the bimetallic element on the spring element has the disadvantage that it is subjected to high mechanical stresses and can be damaged, in particular after many switching cycles. Supporting on the cover part of the switch housing is less problematic by comparison, but it requires, on the one hand, that the switching mechanism be adapted very precisely to the manufacturing tolerances of the housing assembly and, on the other hand, that the bimetallic element in its hot configuration usually has to bend very strongly until it reaches the cover part with its outer edge and presses down the movable contact part with its center.

[0021] However, by using an abutment provided on the spacing 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 has to bend slightly, since the spacing element can be arranged very close to the bimetallic element and the spring element. Mechanical wear on the spacing element is also harmless, since, for example, the spacing element can be constructed to be more stable than the spring element.

[0022] The above-mentioned advantages resulting from the permanent electrical connection between the spring element and the current-carrying switch housing can also be achieved by means of the spacer element in the switch according to the invention.

[0023] Therefore, the above mentioned objects are fully achieved.

[0024] The spring element is supported on the spacing element in the high temperature state of the switching mechanism, and the spring element is preferably spaced apart from the spacing element in the low temperature state of the switching mechanism. Therefore, in the low temperature state of the switch, the spring element does not contact the spacing element.

[0025] In a refinement, the at least one portion of the spring element comprises an outer edge of the spring element, the at least one portion being arranged between the spacing element and the switch housing and being held in place by the interaction of the spacing element with the switch housing.

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

[0027] In another refinement, the at least one portion of the bimetallic element comprises an outer edge of the bimetallic element, the at least one portion being arranged between the spring element and the spacing element and being supported on the spacing element in a high temperature state of the switching mechanism.

[0028] In other words, in the high temperature state of the switching mechanism, the outer edge of the bimetallic element rests on the spacing element. In the low temperature state of the switching mechanism, the outer edge is preferably spaced apart from the spacing element. This also makes it possible to arrange the switching mechanism in a way that saves as much space as possible. In addition, the spacing element can be placed on the radial outer edge of the switching mechanism to save space without interfering with other components of the switching mechanism.

[0029] In another refinement, the at least one portion of the spring element arranged between the spacing element and the switch housing is: (i) clamped indirectly or directly between the spacing element and the lower part; or (ii) clamped indirectly or directly between the spacing element and the cover part.

[0030] Such a clamping arrangement between the spacing element and the lower part or between the spacing element and the cover part is particularly easy to achieve for fixing the position of the spring element. Thus, during assembly of the switch, the spring element can simply be inserted into the interior of the switch housing at the desired position, the spacing element can be placed on top or underneath, and the switch housing can then be closed by fixing the cover part to the lower part (or vice versa). As long as the cover part is fixed to the lower part, the position of the spring element is then automatically fixed. This does not require any additional effort during the assembly process.

[0031] By "indirectly clamped", the term means that the spring element is clamped by the spacing element and the lower part, or by the spacing element and the cover part, but the spring element does not necessarily have to be in direct contact with both components. Furthermore, housing components or elements may be arranged between them. In particular, for example, an insulating film or other intermediate layer may be arranged between the above-mentioned components.

[0032] In another refinement, the spacing element comprises a spacing ring.

[0033] The spacer element is preferably designed as a spacer ring. Thus, the spacer element can be designed as a standard device. Providing the spacer element does not incur additional costs, or if it does, only insignificant additional costs. The spacer element itself can be made of an electrically conductive material (e.g. metal) or a non-conductive material (e.g. plastic).

[0034] In another refinement, the spacing element has a generally L-shaped cross-section.

[0035] By "substantially L-shaped cross-section" the term means that the cross-sectional area of ​​the spacing element comprises a shape at least similar to an L-shape. Preferably, the shape of the cross-sectional area corresponds to an L-shape.

[0036] In another refinement, a first side of the spring element facing the bimetallic element faces the contact surface.

[0037] Therefore, the bimetallic element is arranged on the same side of the spring element as the contact surface of the fixed mating contact part is arranged on it. If the contact surface of the fixed mating contact part is arranged above the spring element, the bimetallic element is also arranged above the spring element. On the other hand, if the contact surface of the fixed mating contact part 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 bent in the same direction both in the low temperature state of the switching mechanism and in the high temperature state of the switching mechanism. In the high temperature state of the switching mechanism, the center of the bimetallic element can, for example, be pressed directly against the center area of ​​the spring element in order to lift the movable contact part away from the contact surface of the fixed mating contact part.

[0038] In another refinement, the spacer element protrudes from the first side of the spring element in a first direction, and the spacer element includes a support surface, and the at least one portion of the bimetallic element is supported on the support surface in the high temperature state of the switching mechanism, wherein the support surface is oriented transversely to the first direction, preferably orthogonal to the first direction.

[0039] In the present case, the term "transverse" does not necessarily mean an orthogonal or perpendicular orientation. Instead, it is understood to refer to any type of non-parallel orientation. Thus, an inclined orientation with an angle not equal to 0° also falls under the term "transverse".

[0040] In a low temperature state of the switching mechanism, the at least one portion of the bimetallic element is preferably spaced apart from the support surface.

[0041] Due to the described substantially L-shaped cross-sectional shape of the spacing element, it can easily serve as a kind of retaining claw, against which the bimetallic element can be supported on the edge in the hot state of the switching mechanism. At the same time, the spacing element preferably lies flat on the spring element and serves as a retaining device for the spring element, by which the spring element is fixed in its position in the switch housing.

[0042] In a further development, the spacing element is clamped in the switch housing by the interaction of the lower part with the cover part.

[0043] This has the advantage that the spacing element is automatically fixed in its position after the switch housing is closed. This also automatically fixes the at least one part of the spring element in its position after the switch housing is closed. The spacing element can be clamped directly or indirectly between the lower part and the cover part. If the lower part and the cover part as well as the spacing 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 spacing element and the lower part or between the spacing element and the cover part.

[0044] In a further development, the spring element comprises at least one compensating portion between the outer edge and the inner region, the at least one compensating portion being configured to be elastic in the radial direction and enabling a mechanical deformation of the spring element.

[0045] The at least one compensating portion has the advantage that it compensates or at least reduces internal deformations that may occur due to the clamping of the spring element on the edge side when the switching mechanism is displaced. Otherwise, such internal deformations and the resulting internal forces would lead to mechanical stresses and aging of the spring element, which would limit the service life of a switch equipped with this spring element.

[0046] Such a "compensation portion" is therefore to be understood in the present case as a region of the spring element which is constructed to yield or be flexible in the radial direction and which enables a radial evasive or expansion movement within the spring element, although the outer edge of the spring element is firmly clamped and thus cannot move in the radial direction, or at least only very slightly. The compensating portion can therefore also be referred to as an expansion structure.

[0047] In a further development, the movable contact part is fixed to the spring element in a material-locking manner.

[0048] For example, the movable contact part is soldered or welded to the spring element. This makes the assembly of the switching mechanism simple and inexpensive, since the contact part does not slide during assembly. Preferably, the movable contact part is arranged in a central, middle area of ​​the spring element.

[0049] In another development, the bimetallic element is held captively on the movable contact part (and the spring element), but with play.

[0050] This means that the spring element, the bimetallic element and the movable contact part form a unit, so that the switching mechanism can be assembled and temporarily stored as a separate semi-finished component. The switching mechanism can also be checked separately, because the bimetallic element is held captive on the movable contact part, but with play, i.e., is correspondingly loose or loose, and can therefore deform unhindered between its low temperature configuration and its high temperature configuration.

[0051] In a further development, the bimetallic element and the spring element are each substantially disc-shaped, and the movable contact part is fixed centrally on the spring part.In a particularly preferred embodiment, both the spring element and the bimetallic element are each disc-shaped.

[0052] In a further development, a first electrical terminal of the switch is arranged outside the cover part and a second electrical terminal of the switch is arranged outside the lower part.

[0053] This ensures that the temperature-dependent switch can be easily electrically connected.

[0054] In a further development, the lower part comprises a free upper edge which is flange-connected or bent onto the cover part.

[0055] This results in the simplest and most stable possible 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 to be understood that the features mentioned above and those yet to be explained below can be used not only in the combination indicated in each case but also in other combinations or on their own, without departing from the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Embodiments of the invention are shown in the drawings and are explained in more detail in the following description. The drawings show: Figure 1 is a schematic cross-sectional view of a temperature dependent switch according to a first embodiment, wherein the switch is in its low temperature state; Figure 2 yes Figure 1 A schematic cross-sectional view of a temperature dependent switch is shown with the switch in its high temperature state; Figure 3 is a schematic cross-sectional view of a temperature dependent switch according to a second embodiment, wherein the switch is in its low temperature state; Figure 4 is a schematic cross-sectional view of a temperature dependent switch according to a third embodiment, wherein the switch is in its low temperature state; Figure 5 is a schematic cross-sectional view of a temperature dependent switch according to a fourth embodiment, wherein the switch is in its low temperature state; and Figure 6 is a schematic cross-sectional view of a temperature dependent switch according to a fifth embodiment, wherein the switch is in its low temperature state. DETAILED DESCRIPTION

[0058] Figures 1 to 6 Five different embodiments of a switch according to the invention are shown, each in a schematic sectional view. In each case, the switch is denoted in its entirety by the reference numeral 10 .

[0059] The switch 10 is constructed to be rotationally symmetrical and has a circular shape when viewed from above. The switch 10 comprises 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 closed by a cover part 18. The lower part 16 comprises a raised edge 20, which is bent inwards or flanged in the region of its free upper end and thereby clamps or fixes the cover part 18 to the lower part 16, with an insulating foil 22 interposed between the cover part 18 and the lower part 16.

[0060] 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 relatively high pressure resistance. An 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 encloses the lower part 16. In addition to electrical insulation, the insulating film 22 also ensures sufficient mechanical sealing between the lower part 16 and the cover part 18, thereby sealing the interior of the switch housing 12 from the outside. This prevents liquids or impurities from entering the interior of the housing from the outside.

[0062] The switching mechanism 14 arranged 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 disk-shaped snap-action spring disc.

[0063] The temperature-dependent bimetallic element 26 is preferably designed as a bimetallic disk, which comprises two temperature-dependent configurations, a low-temperature geometry (see Figure 1 ) and high temperature geometries (see Figure 2 ). In the central region 28 of the spring element 24, a contact part 30 is fixed to the spring element 24. The contact part 30 is connected to the spring element 24 in a material-locked manner. For example, the contact part 30 is welded or brazed to the spring element 24. Since the contact part 30 moves together with the spring element 24 relative to the switch housing 12 during the switching operation, the contact part 30 is also referred to as a “moving contact part”.

[0064] The bimetallic element 26 is held captive on the movable contact part 30, but with a gap. The through hole 32 centrally arranged in the bimetallic element 26 has an inner diameter slightly larger than the outer diameter of the movable contact part 30 arranged in the lower area. However, since the outer diameter of the movable contact part 30 in its upper area is larger than the 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 will not accidentally fall off from the switching mechanism 14 despite the freedom of movement of the bimetallic element 26. Therefore, the spring element 24, the bimetallic element 26 and the movable contact part 30 illustrate a captive unit of the switching mechanism 14, which can be pre-produced as a semi-finished product and inserted into the switch housing 12 as a whole during the assembly of the switch 10.

[0065] exist Figure 1 In the cold state 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 the fixed contact part 36. Figure 1 In the exemplary embodiment shown, the fixed contact element 36 is arranged on an underside 38 of the cover element 18 facing the lower element 16 .

[0066] In the region of the radial outer edge 40 of the spring element 24, the spring element 24 is fixed in the switch housing 12. More precisely, in Figure 1 In the embodiment shown, a radially outer portion 42 forming an outer edge 40 of the spring element 24 is clamped between a spacing element 44 and the lower part 16 of the switch housing 12. The spacing element 44 itself is also clamped between the lower part 16 and the cover part 18 in the switch housing 12. The spacing 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] In assembly Figure 1When the switch 10 shown is used, the switching mechanism 14 is first inserted into the lower part 16. The spacing element 44 is then placed on the outer edge portion 42 of the spring element 24, and the cover part is then placed on the spacing element 44, with the insulating film 22 between the cover part and the spacing element 44. Finally, the upper upright edge 20 of the lower part is bent inwards or flanged, whereby the cover part 18 is pressed from above onto the spacing element 44, wherein the spacing element 44 in turn presses onto the spring element 24, whereby the spring element 24 is fixed in place in the switch housing 12. It should be understood that the positional fixation only affects the outer edge portion 42 of the spring element 24, but the central area 28 of the spring element 24 together with the movable contact part 30 can still be moved in the switch housing 12.

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

[0069] The spacing element 44 further comprises a support surface 50 oriented transversely to the first direction 46 and facing the bimetallic element 26 .

[0070] An outer portion 52 of the bimetallic element 26 including an outer edge 54 is arranged between the spring element 24 and the spacer element 44. More specifically, this portion 52 of the bimetallic element 26 is arranged between the support surface 50 and the spring element 24. By means of this outer portion 52, the bimetallic element 26 is supported on the spacer element 44 or on the support surface 50 arranged on the spacer element 44 in the high temperature state of the switching mechanism 14 (see Figure 2 ).

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

[0072] In the low temperature state of the switch 10, the current can therefore flow from the first terminal 56 through the cover part 18 into the fixed contact part 36 and from there via the movable contact part 30, the spring element 24 into the lower part 16 and thence finally to the second terminal 58 (or vice versa). In this low temperature state of the switch 10, the bimetallic element 26 is stored in a more or less stress-free manner.

[0073] If from Figure 1 Starting from the situation shown, the temperature of the device to be monitored by the switch 10 and therefore also the temperature of the switch 10 and the switching mechanism 14 used therein rises above the response temperature of the bimetallic element 26, which then changes from Figure 1 Its low temperature configuration shown in flipped to Figure 2 . As a result, the upper side of the bimetallic element 26 flips from a convex curvature to a concave curvature. The bimetallic element 26 is then supported from below with its outer edge portion 52 on the support surface 50 of the spacing element 44. At the same time, the bimetallic element 26 presses the movable contact part 30 downward with its center and lifts the movable contact part 30 off the contact surface 34. During this switching movement, the bimetallic element 26 exerts a force that resists the force exerted by the spring element 24 on the contact part 30 in the low temperature state. As a result, the spring element 24 also Figure 1 The first convex shape of the upper side is shown flipped to Figure 2 Its concave shape is shown on the upper side.

[0074] This interrupts the current flow through the switch 10. Thus, the switch is opened.

[0075] Although the spring element 24 has edge clamping, in order to allow the spring element 24 to Figure 1 The situation shown is flipped to Figure 2In the case shown, the spring element 24 can be mechanically expanded, preferably with several compensating portions 60. These compensating portions 60 enable the spring element 24 to be expanded and compressed in the radial direction, which in particular prevents internal tensions or deformations of the spring element 24. The compensating portions 60 can have a design similar to that disclosed in DE 10 2013 109 291 A1.

[0076] Another advantage of the fixed clamping of the outer edge 40 of the spring element 24 is that the permanent mechanical and electrical connection between the spring element 24 and the switch housing 12 means that no sparks and / or arcs occur during the switching operation, which is often the case in switching mechanisms in which the edge of the spring element lifts away from the switch housing during the switching operation. This can effectively prevent the contacts from burning out.

[0077] Figure 3 A second embodiment of a switch 10 is shown in a schematic sectional view. Here, the switch 10 is shown again in the low temperature state, wherein the switching mechanism 14 establishes an electrically conductive connection between the first terminal 56 and the second terminal 58. The switching mechanism 14 has the same basic structure as in the first embodiment. However, it is inserted into the switch housing 12, rotated by 180°, that is to say "upside down".

[0078] The spring element 24 is clamped with its edge section 42 between the cover part 18 and the spacing element 44. The spacing element 44 is again arranged in the switch housing 12 in a clamped manner between the lower part 16 and the cover part 18, wherein according to this second embodiment, the spacing element 44 is now clamped between the spring element 24 and the lower part 16, between which the insulating film 22 is inserted.

[0079] The spacing element 44 again has a substantially L-shaped cross section and comprises a support surface 50 against which the bimetallic element 26 in its high temperature configuration can be supported with its outer edge portion 52. The first side 48 of the spring element 24 also 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 embodiment, the fixed contact part 36, on which the contact surface 34 is arranged, is no longer arranged on the cover part 18, but is now arranged on the lower part 16.

[0080] However, the general switching behavior of the switching mechanism 14 is not changed, which is why for simplicity Figure 3 The high temperature state of the switch 10 is not shown again in the second exemplary embodiment shown.

[0081] Figure 4 A third embodiment of the switch 10 according to the present invention is shown, wherein the switch 10 here is in the form of a Figure 1 and Figure 2 The first embodiment shown is constructed in a substantially similar manner. The spring element 24 is clamped again with its outer edge portion 42 between the spacing element 44 and the lower part 16 of the switch housing 12. However, the switching mechanism 14 is constructed slightly differently. Here, the first side 48 of the spring element 24 also faces the bimetallic element 26 and the contact surface 34. However, here, the bimetallic element 26 rests upward on a circumferential snap ring 62 arranged on the movable contact part 30. The spring element 24 abuts against the snap ring 62 from the opposite lower side. The movable contact part 30 is not necessarily connected to the spring element 24 in a material-locked manner. On the contrary, the spring element 24 includes a central through-opening 64 here, and the part of the movable contact part 30 located below the snap ring 62 is inserted into the central through-opening 64 in a shape-locked manner.

[0082] and Figure 1 and Figure 2 Another difference to the first embodiment shown is that the fixed contact element 36 is not arranged on the bottom side 38 of the cover element 18. Figure 4 In the third embodiment shown, a contact-carrying element 66 is arranged in the switch housing 12, to which the fixed contact part 36 is fixed. The contact-carrying element 66 serves as a kind of sub-cover, which is clamped between the lower part 16 and the cover part 18. More precisely, the edge 68 of the contact-carrying element 66 is clamped between the cover part 18 and the spacing element 44, between which the insulating film 22 is inserted.

[0083] 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 the contact carrier element 66 .

[0084] The main advantage of the additional contact support element 66 provided here is that it can be used in a simple design manner to compensate for manufacturing tolerances on the switch housing 12 and the switching mechanism 14. Depending on customer requirements, the contact support element 66 configured as a sub-cover can be pre-formed so that the desired contact pressure is achieved in the low temperature state of the switching mechanism 14. For example, if a high contact pressure is desired between the fixed contact part 36 and the movable contact part 30 when the switch 10 requires a high performance level than when the switch requires a lower performance level, a contact support element 66 of a different shape can be inserted into the switch housing 12. In other words, the contact pressure between the switching mechanism 14 and the fixed contact part 36 can be adjusted very easily by means of the contact support element 66, without having to change the switch housing 12 itself for this purpose. It should be understood that by setting the corresponding contact pressure, the contact resistance between the switching mechanism 14 and the fixed contact part 36 is also automatically set accordingly. The fact that this setting can be more or less determined only by the shape of the contact-carrying element 66 provides a huge cost advantage, since the switch can be adapted to a wide range of specifications without having to change anything on the switching mechanism 14 or the switch housing 12 .

[0085] Figure 5 The fourth embodiment of the switch 10 according to the present invention shown also follows this principle. Figure 4 The illustrated embodiment differs in that here only the contact surface 34 is arranged directly on the underside of the contact-carrying element 66. The additional fixed contact part 36 is omitted.

[0086] Figure 6 The fifth embodiment shown also follows the above-mentioned principle. However, here, the contact portion carrier element 66 is constructed as a second spring element 70, to which the contact part 36 is fixed together with the contact surface 34 arranged on the contact part 36. With the help of the second spring element 70, the contact pressure between the movable contact part 30 and the contact surface 34 can be further increased, so that the contact resistance between the two devices can be further reduced. The second spring element 70 exerts a force on the contact part 36, which is opposite to the force exerted by the first spring element 24 on the movable contact part 30.

[0087] Finally, about Figures 4 to 6 In the embodiment shown, it should also be mentioned that the second terminal 58 of the switch is designed to be connected to Figures 1 to 3 The embodiment shown is slightly different. This is because the terminal 58 is designed here as a recess provided in the lower part 16, into which a circumferential connecting ring 72 can be inserted, which circumferential connecting ring 72 is preferably welded to the lower part 16. This connecting ring 58 can not only serve as an electrical connection, but can also be connected to a conveyor belt during the production of the switch 10.

Claims

1. A temperature-dependent switch (10), comprising: - a switch housing (12), the switch housing (12) having a lower part (16) and a cover part (18) closing the lower part (16); - a temperature-dependent switching mechanism (14), the temperature-dependent switching mechanism (14) being arranged in the switch housing (12) and comprising a movable contact part (30), a bimetallic element (26) and a spring element (24) interacting with the movable contact part (30), wherein the switching mechanism (14) is configured to switch between a low temperature state and a high temperature state in a temperature-dependent manner, 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 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 spacing element (44), which is arranged inside the switch housing (12) between the lower part (16) and the cover part (18); wherein at least one portion (42) of the spring element (24) is arranged between the spacing element (44) and the switch housing (12) and is fixed in place by the interaction of the spacing element (44) and the switch housing (12), and At least one portion (52) of the bimetallic element (26) is arranged between the spring element (24) and the spacing element (44), and is supported on the spacing 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 portion (42) of the spring element (24) arranged between the spacing element (44) and the switch housing (12) comprises an outer edge (40) of the spring element (24).

3. The temperature dependent switch of claim 1 , wherein: The at least one portion (52) of the bimetallic element (26) disposed between the spring element (24) and the spacing element (44) comprises an outer edge (54) of the bimetallic element (26).

4. The temperature dependent switch of claim 1, wherein: The at least one portion (42) of the spring element (24) arranged between the spacing element (44) and the switch housing (12) is: (i) clamped indirectly or directly between the spacing element (44) and the lower part (16); or (ii) clamped indirectly or directly between the spacing element (44) and the cover part (18).

5. The temperature dependent switch of claim 1, wherein: The spacing element (44) comprises a spacing ring.

6. The temperature dependent switch of claim 1, wherein: The spacer element (44) has an L-shaped cross section.

7. The temperature dependent switch of claim 1, wherein: A first side (48) of the spring element (24) facing the bimetallic element (26) faces the contact surface (34).

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

9. The temperature dependent switch of claim 1, wherein: The spacer element (44) is clamped in the switch housing (12) by the interaction of the lower part (16) and the cover part (18).

10. The temperature dependent switch of claim 1, wherein: The spring element (24) comprises at least one compensating portion (60) between an outer edge (54) and an inner region (28), the at least one compensating portion (60) being configured to be elastic in the radial direction and capable of mechanically deforming the spring element (24).

11. The temperature dependent switch of claim 1 , wherein: The movable contact part (30) is fixed to the spring element (24) in a material-locked manner.

12. The temperature dependent switch of claim 1, wherein: The bimetallic element (26) is held captively on the movable contact part (30) but with a gap.

13. The temperature dependent switch of claim 1, wherein: The bimetallic element (26) and the spring element (24) are each substantially disc-shaped, and the movable contact member (30) is centrally mounted on the spring member (24).

14. The temperature dependent switch of claim 1, wherein: The first electrical terminal (56) is arranged outside the cover part (18), and the second electrical terminal (58) is arranged outside the lower part (16).

15. The temperature dependent switch of claim 1, wherein: The lower part (16) comprises a free upper edge (20) which is flanged or bent onto the cover part (18).

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