Temperature-dependent switch

Abstract

A temperature-dependent switch having a housing that comprises a cover part and an electrically conductive lower part. The switch further comprises a first external contact surface arranged on the upper side of the cover part, and a second external contact surface provided externally on the housing. Still further, the switch comprises a temperature-dependent switching mechanism that is arranged in the housing and that, depending on its temperature, establishes or opens an electrically conductive connection between the first and the second external contact surfaces. A circumferential cutting burr acting as a sealing means is furthermore provided, that penetrates into the insulating foil or the cover part, wherein the cutting burr is arranged on a sealing ring that is connected to the lower part by means of a non-positive, positive and/or firmly bonded connection.

Claims

1. A temperature-dependent switch, comprising: a housing that comprises (i) a cover part having a lower side and an upper side, (ii) an electrically conductive lower part, and (iii) an insulating foil that is arranged between the lower side of the cover part and the electrically conductive lower part, wherein a first external contact surface is arranged on the upper side of the cover part, a second external contact surface is provided externally on the housing, and wherein the temperature-dependent switch further comprises a circumferential cutting burr that penetrates into the insulating foil, the circumferential cutting burr being arranged on a sealing ring that is connected to the electrically conductive lower part by means of a non-positive, positive and/or firmly bonded connection; and a temperature-dependent switching mechanism that is arranged in the housing and that, depending on its temperature, establishes or opens an electrically conductive connection between the first external contact surface and the second external contact surface.

2. The temperature-dependent switch according to claim 1, wherein the circumferential cutting burr is circumferentially closed in itself.

3. The temperature-dependent switch according to claim 1, wherein the circumferential cutting burr protrudes from an upper side of the sealing ring with a height that is between 10 μm and 50 μm.

4. The temperature-dependent switch according to claim 1, wherein the sealing ring is formed integrally with the circumferential cutting burr.

5. The temperature-dependent switch according to claim 4, wherein the sealing ring is a turned part or a punched part.

6. The temperature-dependent switch according to claim 1, wherein the connection between the sealing ring and the electrically conductive lower part is a glued connection, a soldered connection or a welded connection.

7. The temperature-dependent switch according to claim 1, wherein the electrically conductive lower part comprises an upper edge, and wherein the upper edge overlaps the cover part.

8. The temperature-dependent switch according to claim 7, wherein a circumferential shoulder is provided in the electrically conductive lower part, wherein the cover part is arranged directly or indirectly on the circumferential shoulder, and wherein the upper edge of the electrically conductive lower part presses the cover part onto the circumferential shoulder.

9. The temperature-dependent switch according to claim 8, wherein a circumferential recess is provided in the circumferential shoulder, and wherein the sealing ring is arranged in the circumferential shoulder.

10. The temperature-dependent switch according to claim 1, wherein the electrically conductive lower part comprises a first material, and wherein the sealing ring comprises a second material, the first material having a higher hardness than the second material.

11. The temperature-dependent switch according to claim 1, wherein a circumferential notch is provided in the electrically conductive lower part, and wherein the sealing ring comprises on a lower side of the sealing ring facing the circumferential notch an annular bead or feather key that is fitted, pressed or flanged into the circumferential notch.

12. The temperature-dependent switch according to claim 1, wherein the temperature-dependent switching mechanism carries a movable contact part that interacts with a stationary counter-contact that is arranged on the lower side of the cover part and that interacts with the first external contact surface.

13. The temperature-dependent switch according to claim 1, wherein the temperature-dependent switching mechanism comprises a bimetal part.

14. The temperature-dependent switch according to claim 1, wherein the temperature-dependent switching mechanism comprises a snap-action spring disc.

15. A temperature-dependent switch, comprising: a housing that comprises (i) a cover part having a lower side and an upper side, and (ii) an electrically conductive lower part, wherein at least a part of the cover part comprises an electrically insulating material, wherein a first external contact surface and a separate second external contact surface are arranged on the upper side of the cover part, and wherein the temperature-dependent switch further comprises a circumferential cutting burr that penetrates into the cover part, the circumferential cutting burr being arranged on a sealing ring that is connected to the electrically conductive lower part by means of a non-positive, positive and/or firmly bonded connection; and a temperature-dependent switching mechanism that is arranged in the housing and that, depending on its temperature, establishes or opens an electrically conductive connection between the first external contact surface and the second external contact surface.

16. The temperature-dependent switch according to claim 15, wherein the temperature-dependent switching mechanism carries a current transfer member that interacts with two stationary counter-contacts that are arranged on the lower side of the cover part and that interact with the first external contact surface and the second external contact surface.

17. The temperature-dependent switch according to claim 15, wherein the sealing ring is formed integrally with the circumferential cutting burr.

18. The temperature-dependent switch according to claim 15, wherein the connection between the sealing ring and the electrically conductive lower part is a glued connection, a soldered connection or a welded connection.

19. The temperature-dependent switch according to claim 15, wherein the electrically conductive lower part comprises an upper edge, wherein the upper edge overlaps the cover part, wherein a circumferential shoulder is provided in the electrically conductive lower part, wherein a circumferential recess is provided in the circumferential shoulder, wherein the sealing ring is arranged in the circumferential shoulder, and wherein the upper edge of the electrically conductive lower part presses the cover part onto the circumferential shoulder.

20. The temperature-dependent switch according to claim 15, wherein the temperature-dependent switching mechanism comprises a bimetal part and a snap-action spring disc.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a schematic sectional view of a first embodiment of the switch in a first switching position;

(2) FIG. 2 shows a schematic sectional view of the first embodiment of the switch shown in FIG. 1, in a second switching position;

(3) FIG. 3 shows a schematic sectional view in detail of a first connection variant of a sealing ring with a lower part of the switch;

(4) FIG. 4 shows a schematic sectional view in detail of a second connection variant of the sealing ring with the lower part of the switch;

(5) FIG. 5 shows a schematic sectional view in detail of a third connection variant of the sealing ring with the lower part of the switch;

(6) FIG. 6 shows a schematic sectional view of a second embodiment of the switch in a first switching position; and

(7) FIG. 7 shows a schematic sectional view of the second embodiment of the switch shown in FIG. 6, in a second switching position.

DESCRIPTION OF PREFERRED EMBODIMENTS

(8) FIG. 1 shows a schematic sectional side view of a switch 10, which is rotationally symmetrical in top view and preferably has a circular shape.

(9) The switch 10 comprises a housing 12, in which a temperature-dependent switching mechanism 14 is arranged. The housing 12 comprises a pot-like lower part 16 and a cover part 18, which is held on the lower part 16 by a bent or flanged rim 20.

(10) In the first embodiment shown in FIG. 1, both the lower part 16 and the cover part 18 are made of an electrically conductive material, preferably metal. The cover part 18 lies on a shoulder 24 inside the lower part 16 with an interposed insulating foil 22. The upper edge 20 of the lower part 16 is bent radially inwards in such a way that it presses the interposed insulating foil 22 and the cover part 18 onto the circumferential shoulder 24 if it is bent further towards the upper side of the cover part 18 compared to the situation shown schematically in FIG. 1.

(11) The insulating foil 22 provides an electrical insulation of the cover part 18 against the lower part 16. In addition, the insulating foil 22 also provides a mechanical seal that prevents liquids or impurities from entering the inside of the housing from the outside.

(12) The insulating foil 22 runs inside the housing 12 parallel to the cover part 18 along the lower side 25 of the cover part, from where it is led laterally between the cover part 18 and the circumferential shoulder 24 up to the upper side 23 of the cover part 18 and out of the housing 12. The bent or flanged upper edge 20 of the lower part 16 lies flat on the upper edge section of the insulating foil 22 and presses it towards the upper side 23 of the cover part 18.

(13) On the upper side 23 of the cover part 18, a further insulating cover 26 is provided, which extends radially outwards up to the insulating foil 22.

(14) The switching mechanism 14 comprises a temperature-independent spring part 28, which is designed as a spring disc, and a temperature-dependent snap-action part 30, which is designed as a bimetal snap-action disc.

(15) The spring part 28 is preferably designed as a bistable spring disc. Accordingly, the spring disc 28 has two temperature-independent stable geometric configurations. The first geometric configuration is shown in FIG. 1.

(16) The temperature-dependent bimetal snap-action disc 30 is preferably designed as a bistable snap-action disc. The snap-action disc 30 has two temperature-dependent configurations, a geometrical high temperature configuration and a geometrical low temperature configuration. In the first switching position of the switching mechanism 14 shown in FIG. 1, the snap-action disc 30 is in its low-temperature configuration.

(17) The spring disc 28 lies with its edge 32 on an inner bottom surface 34 of the lower part 16. The inner bottom surface 34 is substantially concave in shape and is slightly raised at the point where the edge 32 of the spring disc 28 rests in the first switching position shown in FIG. 1 compared to the central area of the inner bottom surface 34. The snap-action disc 30 lies with its edge 36 on the spring disc 28 in its low temperature configuration shown in FIG. 1.

(18) The spring disc 28 is fixed with its center 38 to a movable contact member 40 of the switching mechanism 14. The bimetal snap-action disc 30 is also fixed with its center 42 to this contact member 40. In this way, the temperature-dependent switching mechanism 14 is a captive unit comprising the contact member 40, the spring disc 28 and the bimetal snap-action disc 30. During the assembly of the switch 10, the switching mechanism 14 can thus be inserted as a unit directly into the lower part 16.

(19) On its upper side, the movable contact member 40 comprises a movable contact part 44. The movable contact part 44 interacts with a stationary counter-contact 46, which is arranged at the lower side 25 of the cover part 18. In this embodiment, the upper side 23 of the cover part 18, which is connected to the stationary counter-contact 46 in an electrically conductive manner, serves as first external contact surface 48. The outer side of the lower part 16 serves as second external contact surface 50. For example, the outer bottom surface or the outer side of the bent upper edge 20 of the lower part 16 can serve as second external contact surface 50.

(20) In the closed switching position of switch 10 shown in FIG. 1, the movable contact part 44 is pressed against the stationary counter-contact 46 by the spring disc 28. Since electrically conductive spring disc 28 is, with its edge 32, in contact with the lower part 16, an electrically conductive connection is established between the two external contact surfaces 48, 50.

(21) If the temperature inside the switch 10 now increases above the switching temperature of the bimetal snap-action disc 30, the latter snaps from its convex low temperature configuration shown in FIG. 1 to its concave high temperature configuration shown in FIG. 2.

(22) In the high-temperature configuration shown in FIG. 2, the bimetal snap-action disc 30 has its edge 36 supported on the lower side of the insulating foil 22 and pushes the movable contact member 40 downwards with its center 42. This lifts the movable contact member 44 off the stationary counter-contact 46. The spring disc 28 thereby snaps from its first geometrically stable configuration shown in FIG. 1 to its second geometrically stable configuration shown in FIG. 2.

(23) Since switch 10 is now open and the power supply to the device to be protected is interrupted, the device to be protected and therefore also switch 10 can cool down again. When the temperature inside the switch 10 then cools down to a temperature below the reset temperature of the bimetal snap-action disc 30, it snaps back from its high temperature configuration shown in FIG. 2 to its low temperature configuration shown in FIG. 1. The spring disc 28 also snaps back into its first geometrically stable configuration and brings the movable contact part 44 back into contact with the stationary counter-contact 46. The switch 10 or the electric circuit is then closed again.

(24) In order to improve the sealing of the inside of the housing, a sealing ring 52 is arranged in the area of the circumferential shoulder 24, wherein a cutting burr 54 is provided on the upper side of the sealing ring 52. The cutting burr 54 is preferably designed as a circumferentially closed cutting burr that is integrally connected to the sealing ring 52.

(25) Sealing ring 52 including the cutting burr 54 arranged thereon form a kind of inlay that is inserted into the lower part 16 in the area of the circumferential shoulder 24.

(26) The sealing ring 52 including the cutting burr arranged on it is preferably produced as a punched part. This punched part is connected to the lower part 16 by means of a positive, non-positive and/or firmly bonded connection in the area of the circumferential shoulder 24 (e.g. on, next to, below or in the circumferential shoulder 24).

(27) The lower part 16 and the sealing ring 52 can thus be produced as two separate components that are subsequently joined together. This enables a very easy production of both components, as both the lower part 16 and the sealing ring 52 including the cutting burr 54 arranged on it can be produced as low-cost punched parts.

(28) FIGS. 3-5 show three different embodiments of how the sealing ring 52 including the cutting burr 54 arranged on it can be attached on the lower part 16.

(29) According to the first embodiment shown in FIG. 3, the sealing ring 52 is attached to the lower part 16 by means of a firmly bonded connection. For example, the sealing ring 52 is glued, soldered, or welded to the lower part 16 in the area of the shoulder 24. In addition, the sealing ring 52 can be fitted into the base 16 in a kind of press fit. This additionally stabilizes the connection between sealing ring 52 and base 16. In this respect, it is particularly preferred that the circumferential shoulder 24 or the lower part 16 is made of a material that is harder than the material from which the sealing ring 52 is made.

(30) FIG. 4 shows another embodiment in which the sealing ring 52 is arranged in a circumferential recess 56, which is inserted into the shoulder 24 of the lower part 16. For example, the circumferential recess 56 can be a groove-shaped recess that is inserted into shoulder 24 from above and into which the sealing ring 52 can be pressed or flanged.

(31) In the third embodiment shown in FIG. 5, a circumferential notch 58 is provided in the lower part 16, into which notch a bead 62 located on the lower side 60 of the sealing ring is fitted, pressed or flanged. In the embodiment shown in FIG. 5, the notch 58 has an substantially V-shaped cross-section. The bead 62, on the other hand, has a substantially semicircular or U-shaped cross-section. However, it goes without saying that other cross-sectional shapes can also be provided for the notch 58 and the bead 62. The cross-sectional shapes of notch 58 and bead 62 can also be equivalent to each other. However, it is preferred that the bead 62 has an oversize compared to the notch 58.

(32) All three embodiments shown in FIGS. 3-5 have in common that the cutting burr 54 provided on the upper side of the sealing ring 52 cuts into the insulating foil 22. As a result, the cutting burr 54 forms a mechanical barrier that prevents liquids or other impurities from entering the interior of housing 12 between the lower side of the insulating foil 22 and the lower part 16.

(33) The cutting burr 54 preferably protrudes above shoulder 24 with a height h (see FIG. 3) that lies between 10 μm and 50 μm. The insulating foil 22 typically has a thickness in the range of 100 μm. Thus, the cutting burr 54 cuts into the insulating foil 22 to a maximum of 50% of the thickness. The electrically insulating properties of the insulating foil 22 are therefore maintained.

(34) FIGS. 6 and 7 show a second embodiment of the switch 10. FIG. 6 shows the closed switching position of the switch 10. FIG. 7 shows the open switching position of the switch 10.

(35) The switch 10 according to the second embodiment shown in FIGS. 6 and 7 differs from the first embodiment shown in FIGS. 1 and 2 mainly in the construction of the housing 12′ and the construction of the switching mechanism 14′.

(36) The lower part 16′ is again made of electrically conductive material. The flat cover part 18′ is made of electrically insulating material. Accordingly, no insulating foil 22, which must be inserted between the lower part 16′ and the cover part 18′, is necessary here. In principle, however, an insulating foil 22 as shown in FIGS. 1 and 2 can also be provided for the switch construction shown in FIGS. 6 and 7. In this case, however, it would only serve to mechanically seal the inside of the housing and not to electrically insulate the cover part 18′ from the lower part 16′.

(37) Between the cover part 18′ and the lower part 16′ there is also a sealing ring 52′, on the upper side of which a cutting burr 54′ is arranged. In this embodiment, the cutting burr 54′ penetrates directly into the lower side 25 of the cover part 18′. As before, it serves as a mechanical barrier to prevent impurities from penetrating into the inside of the housing of the switch 10. Accordingly, the cutting burr 54′ is also preferably designed as a circumferential, closed cutting burr.

(38) The sealing ring 52′ is inserted into the lower part 16′. Its lower side lies on a circumferential shoulder 64 running around the inside of the lower part 16′. The sealing ring 52′ thus also acts as a spacer ring that keeps the upper part 18′ at a distance from the lower part 16′.

(39) The sealing ring 52′ is, similar to the first embodiment of the switch 10 shown in FIGS. 1 and 2, connected to the lower part 16′ by means of a non-positive, positive and/or firmly bonded connection. As already mentioned above, the sealing ring 52′ can be glued, welded or soldered to the lower part 16′, for example. Likewise, the sealing ring 52′ can also be connected to the lower part 16′ by flanging it with a positive and/or non-positive fit. Furthermore, it is possible to clamp the sealing ring 52′ by means of a press fit in the lower part 16′. The fastening options shown in FIG. 3-5 therefore also apply equally to the fastening of the sealing ring 52′ to the lower part 16′.

(40) In the second embodiment of the switch 10 shown in FIGS. 6 and 7, the two external contact surfaces 48′, 50′ are arranged on the upper side 23 of cover part 18′. These two external contact surfaces 48′, 50′ are formed on the upper side of two rivets arranged at a distance from each other and extending through the cover part 18′. On the lower side of each rivet, there is a stationary contact 66, 68, which protrudes downward from the lower side 25 of the cover part 18′.

(41) The switching mechanism 14′ is also slightly different from the previous one. The movable contact member 40′ comprises a current transfer member 70, which is designed as a contact plate, the upper side of which is coated with an electrically conductive coating, so that it provides an electrically conductive connection between the two contacts 66, 68, as shown in FIG. 6.

(42) The current transfer member 70 is connected to the spring disc 28 and the bimetal snap-action disc 30 via a rivet 72, which is also to be regarded as part of the contact member 40′.

(43) Similarly as before, the bimetal snap-action disc 30 snaps over from the low temperature configuration shown in FIG. 6 to the high temperature configuration shown in FIG. 7 when its switching temperature is reached, which also causes the spring disc 28 to snap over from its first geometric position shown in FIG. 6 to its second geometric position shown in FIG. 7. The current transfer member 70 is lifted off the two stationary contacts 66, 68, so that the circuit is interrupted.

(44) An advantage of the switch design shown in FIGS. 6 and 7 is that, in contrast to the first embodiment of switch 10 shown in FIG. 1-2, no current flows through either the spring disc 28 or the bimetal snap-action disc 30 when switch 10 is closed. This current flows only from the first external contact surface 48′ via the first stationary contact 66, the current transfer member 70 and the second stationary contact 68 to the second external contact surface 50′.

(45) It is to be understood that the foregoing is a description of one or more preferred exemplary embodiments of the invention. The invention is not limited to the particular embodiment(s) disclosed herein, but rather is defined solely by the claims below. Furthermore, the statements contained in the foregoing description relate to particular embodiments and are not to be construed as limitations on the scope of the invention or on the definition of terms used in the claims, except where a term or phrase is expressly defined above. Various other embodiments and various changes and modifications to the disclosed embodiment(s) will become apparent to those skilled in the art. All such other embodiments, changes, and modifications are intended to come within the scope of the appended claims.

(46) As used in this specification and claims, the terms “for example,” “e.g.,” “for instance,” “such as,” and “like,” and the verbs “comprising,” “having,” “including,” and their other verb forms, when used in conjunction with a listing of one or more components or other items, are each to be construed as open-ended, meaning that the listing is not to be considered as excluding other, additional components or items. Other terms are to be construed using their broadest reasonable meaning unless they are used in a context that requires a different interpretation.