TEMPERATURE-DEPENDENT SWITCH

Abstract

A temperature-dependent switch, comprising a temperature-dependent switching mechanism having a switching mechanism unit and a switching mechanism housing, in which the switching mechanism unit is arranged and held captively therein. Furthermore, the switch comprises a switch housing, in which the switching mechanism housing is arranged and held captively therein. The switching mechanism housing surrounds the switching mechanism unit from a first housing side, a second housing side opposite the first housing side, and a housing circumferential side extending between and transversely to the first and the second housing sides, and on the first housing side comprises an opening through which a movable contact part of the switching mechanism interacts with a stationary contact part arranged on the switch housing. The switching mechanism housing comprises an electrically conductive base body, which forms at least part of the second housing side, said part of the second housing side forming a freely accessible outside of the switch. The switch further comprises an insulator, which electrically insulates the base body of the switching mechanism housing from the switch housing and is arranged inside the switch housing.

Claims

1. A temperature-dependent switch), comprising: a temperature-dependent switching mechanism having a switching mechanism unit, which comprises a movable contact part coupled to a bimetallic snap-action disc, and having a switching mechanism housing, in which the switching mechanism unit is arranged and held captively therein; a switch housing, in which the switching mechanism housing is arranged and held captively therein, wherein the switch housing comprises a stationary contact part, which acts as a mating contact to the movable contact part; and an insulator arranged inside the switch housing; wherein the switching mechanism housing surrounds the switching mechanism unit from a first housing side, a second housing side opposite the first housing side, and a housing circumferential side extending between and transversely to the first and the second housing sides, wherein the switching mechanism housing on the first housing side comprises an opening through which the movable contact part interacts with the stationary contact part, wherein the switching mechanism housing comprises an electrically conductive base body, which forms at least part of the second housing side, said part of the second housing side forming a freely accessible outside of the temperature-dependent switch, and wherein the insulator electrically insulates the base body of the switching mechanism housing from the switch housing.

2. The temperature-dependent switch according to claim 1, wherein the insulator comprises an annular body.

3. The temperature-dependent switch according to claim 1, wherein the insulator is fastened to the base body of the switching mechanism housing.

4. The temperature-dependent switch according to claim 3, wherein at least one holding element is formed on the base body of the switching mechanism housing, and wherein the insulator is fastened to the base body by means of the at least one holding element.

5. The temperature-dependent switch according to claim 1, wherein the base body of the switching mechanism housing is integrally formed in one piece.

6. The temperature-dependent switch according to claim 1, wherein an outer circumferential surface of the insulator abuts an inner circumferential surface of the switch housing.

7. The temperature-dependent switch according to claim 1, wherein the insulator forms at least a part of the housing circumferential side of the switching mechanism housing and/or at least a part of the first housing side of the switching mechanism housing.

8. The temperature-dependent switch according to claim 1, wherein an inner circumferential surface of the insulator radially delimits the opening.

9. The temperature-dependent switch according to claim 1, wherein a diameter of the opening is smaller than a diameter of the bimetallic snap-action disc that is measured parallel to the diameter of the opening.

10. The temperature-dependent switch according to claim 1, wherein the switching mechanism is configured so as, below a response temperature of the bimetallic snap-action disc, to keep the switch in a low-temperature position in which the switching mechanism establishes via the movable contact part an electrical connection between the base body of the switching mechanism housing and the stationary contact part arranged on the switch housing, and, upon exceeding the response temperature, to move the switch to a high-temperature position in which the switching mechanism interrupts the electrical connection.

11. The temperature-dependent switch according to claim 10, wherein the switching mechanism unit further comprises a snap-action spring disc which is coupled to the movable contact part and is supported in the low-temperature position of the switch on an internal surface arranged on the second housing side in an interior of the switching mechanism housing.

12. The temperature-dependent switch according to claim 10, wherein the bimetallic snap-action disc is configured to snap over from a geometrically stable low-temperature configuration to a geometrically stable high-temperature configuration upon exceeding the response temperature, and wherein the bimetallic snap-action disc is supported in its high-temperature configuration on a supporting surface, which is arranged on the first housing side of the switching mechanism housing and is formed on the base body or on the insulator, and thereby keeps the movable contact part at a distance from the stationary contact.

13. The temperature-dependent switch according to claim 11, wherein the switching mechanism unit further comprises a snap-action spring disc which is coupled to the movable contact part and is supported in the low-temperature position of the switch on an internal surface arranged on the second housing side in an interior of the switching mechanism housing.

14. The temperature-dependent switch according to claim 1, wherein the part of the second housing side of the switching mechanism housing, which forms the freely accessible outside of the temperature-dependent switch, comprises an outwardly arched, domed or pot-shaped portion.

15. The temperature-dependent switch according to claim 14, wherein the outwardly arched, domed or pot-shaped portion comprises a first contact surface, which lies in a common plane with a second contact surface arranged on the switch housing.

16. The temperature-dependent switch according to claim 1, wherein an intermediate space extending circumferentially between the switching mechanism housing and the switch housing is filled with insulating compound.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0071] FIG. 1 shows a schematic sectional view of the temperature-dependent switch according to a first exemplary embodiment, the switch being shown in its low-temperature position;

[0072] FIG. 2 shows a schematic sectional view of the switch shown in FIG. 1, the switch being shown in its high-temperature position;

[0073] FIG. 3 shows a schematic sectional view of the temperature-dependent switch according to a second exemplary embodiment, the switch being shown in its low-temperature position;

[0074] FIGS. 4A-4C show schematic sectional views illustrating individual processing steps during the manufacturing of the temperature-dependent switch according to the exemplary embodiment shown in FIG. 1; and

[0075] FIG. 5 shows a schematic top view from below of the switching mechanism used in the temperature-dependent switch according to the first exemplary embodiment shown in FIG. 1.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0076] FIGS. 1-2 show a first exemplary embodiment of the switch in each case in a schematic sectional view. The switch is identified therein in its entirety in each case by the reference number 100.

[0077] The switch 100 comprises a temperature-dependent switching mechanism 10, which is arranged in an electrically conductive switch housing 12.

[0078] The switching mechanism 10 comprises a functional switching mechanism unit 14 and a switching mechanism housing 16 surrounding said switching mechanism unit 14. The switching mechanism housing 16 surrounds the switching mechanism unit 14 at least partially from all six spatial directions. However, as explained in detail below, the switching mechanism housing 16 is designed as a partially open housing, and therefore the switching mechanism unit 14 is accessible from outside the switching mechanism housing 16 from at least one spatial direction, preferably from only one spatial direction.

[0079] Owing to the fact that the switching mechanism housing 16 at least partially surrounds the switching mechanism unit 14 from all six spatial directions, the switching mechanism unit 14 is held captively in the switching mechanism housing 16. The switching mechanism unit 14 therefore cannot be detached from the switching mechanism housing 16.

[0080] As long as the switching mechanism 10 is not installed in the switch 100 or its switch housing 12, there is preferably a certain clearance between the switching mechanism unit 14 and the switching mechanism housing 16. However, the switching mechanism unit 14 is firmly braced in the installed state of the switch 100 shown in FIG. 1. In the low-temperature position of the switch 100 shown in FIG. 1, the switching mechanism unit 14 is clamped between the switch housing 12 and the switching mechanism housing 16.

[0081] The switching mechanism unit 14 is constructed in three parts according to the present exemplary embodiment. The switching mechanism unit 14 comprises a temperature-dependent bimetallic snap-action disc 18, a temperature-independent snap-action spring disc 20 and a movable contact part 22. The bimetallic snap-action disc 18 and the snap-action spring disc 20 are held captively on the contact part 22. The switching mechanism unit 14 can thus be produced in advance as a semi-finished product and then inserted as a whole into the switching mechanism housing 16 (see FIG. 4A).

[0082] The switching mechanism 10 together with the switching mechanism unit 14 and the switching mechanism housing 16 also form a semi-finished product for the temperature-dependent switch 100 produced from it later on. Since the three components 18, 20, 22 of the switching mechanism unit 14 are connected captively to one another and the switching mechanism unit 14 is held captively in the switching mechanism housing 16, the switching mechanism 10 can be kept in stock as bulk material until it is installed in the temperature-dependent switch 100.

[0083] The switching mechanism housing 16 surrounds the switching mechanism unit 14 from a first housing side 24, from a second housing side 26 opposite the first housing side 24, and also from a housing circumferential side 28 extending between and transversely to the first and the second housing sides 24, 26.

[0084] Preferably, the switching mechanism housing 16 completely surrounds the switching mechanism unit 14 both from the second housing side 26 and from the housing circumferential side 28. The second housing side 26 and the housing circumferential side 28 thus preferably form closed housing sides of the switching mechanism housing 16. Only the first housing side 24 is a partially open housing side of the switching mechanism housing 16.

[0085] In other words, the housing circumferential side 28 surrounds the switching mechanism unit 14 along the entire circumference, i.e. from a total of four spatial directions oriented orthogonally with respect to one another. Furthermore, the switching mechanism housing 16 completely surrounds the switching mechanism unit 14 from a further spatial direction, namely from a spatial direction oriented orthogonally to the second housing side 26. Only from the sixth spatial direction, which is oriented orthogonally to the first housing side 24, does the switching mechanism housing 16 only partially surround the switching mechanism unit 14.

[0086] On the first housing side 24, the switching mechanism housing 14 comprises an opening 30 through which the movable contact part 22 is accessible from outside the switching mechanism housing 16. Through said opening 30 in the switching mechanism housing 16, the movable contact part 22 of the switching mechanism 10 cooperates with a stationary contact part 32, which is arranged on an inner side 34 of the switch housing 12.

[0087] A diameter D1 of the opening 30 is smaller than a diameter D2, measured parallel thereto, of the bimetallic snap-action disc 18 and/or of the snap-action spring disc 20. Thus, although the movable contact part 22 is accessible from outside the switching mechanism housing 16 through the opening 30, the bimetallic snap-action disc 18 and the snap-action spring disc 20 cannot, however, become detached from the switching mechanism housing 16 or emerge therefrom.

[0088] The switching mechanism housing 16 comprises a base body 36, which is formed from an electrically conductive material, for example, from metal. In the exemplary embodiment shown here, said electrically conductive base body 36 forms the second housing side 26 and the housing circumferential side 28 of the switching mechanism housing 16.

[0089] An upper part of the base body 36, which forms the second housing side 26, simultaneously forms a freely accessible outside of the switch 100. The first housing side 24 and the housing circumferential side 28 are arranged completely within the switch housing 12 and are therefore not accessible from outside the switch 100.

[0090] The first housing side 24 of the switching mechanism housing 16 is formed by an insulator 38 according to the exemplary embodiment shown in FIGS. 1 and 2. It may be a plastics insulator, for example. The insulator 38 is fastened to the base body 36 of the switching mechanism housing 16 on the underside of the switching mechanism housing 16. For this purpose, a plurality of holding claws 40 are provided, which are shown by dashed lines in FIGS. 1 and 2.

[0091] The base body 36 of the switching mechanism housing 16 is preferably integrally formed in one piece. The holding claws 40 are preferably integrally connected to the base body 36.

[0092] According to the exemplary embodiment shown in FIGS. 1 and 2, the switching mechanism housing 16 is thus constructed in two parts, with the base body 36 and the insulator 38 fastened thereto, Of course, other types of holding elements can be used instead of holding claws 40 to connect the insulator 38 to the base body 36. The base body 36 can equally also be adhesively bonded to the insulator 38.

[0093] The insulator 38 is designed as an annular body. Its shape is preferably adapted to the shape of the switching mechanism housing 12. The insulator 38 rests on the inside 34 of the base of the switch housing 12 with the interposition of an insulating film 42. Although the insulating film 42 improves the electrical insulation as well as the seal-tightness of the switch 100, it is not absolutely necessary.

[0094] The insulator 38 lies with its outer circumferential surface 44 on an inner circumferential surface 46 of the switch housing 12 (either directly or with the interposition of the insulating film 42). An inner circumferential surface 48 of the insulator 38 delimits the opening 30, which is provided on the first housing side 24 of the switching mechanism housing 16, in the radial direction.

[0095] During the manufacturing of the switch 100, the switching mechanism housing 16 is inserted together with the insulator 38 into the switch housing 12. The switch housing 12 is preferably formed in one piece from an electrically conductive material, preferably from metal. The switch housing 12 is pot-like. It comprises a base 50 and a side wall 52 encircling the latter transversely, in the circumferential direction, the upper edge 54 of which, after insertion of the switching mechanism housing, is bent over inwards in the direction of the central axis of the switching mechanism housing in order to fix the switching mechanism housing 16 in the switch housing 12.

[0096] The intermediate space 56 between the switching mechanism housing 16 and the switch housing 12 is filled with insulating compound 58. The insulating compound 58 provides a mechanical seal that prevents liquids or contaminants from entering the inside of the switch 100 from the outside. This results in a sealed switch housing 12, in which the switching mechanism housing 16 is held captively.

[0097] Since the switching mechanism housing 12 and the base body 36 of the switching mechanism housing 16 are each made of electrically conductive material, thermal contact can be made via their outer surfaces to an electrical device to be protected.

[0098] The outer surfaces also serve for the electrical connection of the switch 100 at the same time. For example, the outside 60 of the base 50 of the switch housing 12 can act as a first electrical connection and the outside 62 of that part of the base body 36 of the switching mechanism housing 16 which is freely accessible from the outside on the second housing side 26 can act as a second electrical connection.

[0099] In the assembled state of the switch 100, the switching mechanism 10 is clamped between the base body 36 of the switching mechanism housing 16 and the switch housing 12. The insulator 38 provides electrical insulation of the base body 36 of the switching mechanism housing 16 from the switch housing 12.

[0100] This ensures that an electrical contact produced by the switch 100 between the switch housing 12 and the switching mechanism housing 16 can be produced only via the switching mechanism 10. Said electrical contact between the switch housing 12 and the switching mechanism housing 16 that is produced via the switch 100 is produced by the switching mechanism 10 only in the low-temperature position of the switch 100 (see FIGS. 1 and 2).

[0101] In the low-temperature position of the switch 100 that is shown in FIG. 1, the temperature-independent snap-action spring disc 20 is in its first configuration and the temperature-dependent bimetallic snap-action disc 18 is in its low-temperature configuration. The snap-action spring disc 20 presses the movable contact part 22 against the stationary contact part 32, which acts as a mating contact. The switch 100 is thus in its closed position, in which an electrically conductive connection between the outside 62 of the switching mechanism housing 16, which acts as a first switch connection, and the outside 60 of the switch housing 12, which acts as a second switch connection, is produced via the snap-action spring disc 20, the movable contact part 22 and the stationary contact part 32.

[0102] The contact pressure between the movable contact part 22 and the stationary contact part 32 is produced by the snap-action spring disc 20. In this state, the bimetallic snap-action disc 18 is by contrast mounted virtually without any force in the switching mechanism housing 16.

[0103] If the temperature of the device to be protected and thus the temperature of the switch 100 and the bimetallic snap-action disc 18 arranged therein increases to the switching temperature of the bimetallic snap-action disc 18 or above the switching temperature, the bimetallic snap-action disc 18 snaps over from its concave low-temperature position shown in FIG. 1 into its convex high-temperature position shown in FIG. 2. During said snapping-over, the bimetallic snap-action disc 18 is supported with its outer edge 64 on a supporting surface arranged on the upper side of the insulator 38. This means that the snap-action spring disc 20 is simultaneously deflected upwards at its center such that the snap-action spring disc 20 snaps over from its first stable geometric configuration shown in FIG. 1 into its second geometrically stable configuration shown in FIG. 2.

[0104] FIG. 2 shows the high-temperature position of the switch 100, in which the latter is open. The current circuit is therefore interrupted.

[0105] When the device to be protected and thus the switch 100 together with the bimetallic snap-action disc 18 then cool again, the bimetallic snap-action disc 18 snaps over again into its low-temperature position when the switching-back temperature, which is also referred to as the return temperature, is reached, as is shown for example in FIG. 1. This allows a reversible switching behavior to be realized.

[0106] Of course, it is also possible for switching-back of the switch 100 after a snap-over into the high-temperature position has taken place to be prevented by a corresponding closing lock. Such closing locks are used in particular for single-use switches in which switching-back is intended to be prevented.

[0107] It is also possible to provide the switching mechanism unit 14 without a snap-action spring disc 20. In such a case, the switching mechanism unit 14 then only comprises the bimetallic snap-action disc 18 and the movable contact part 22. The bimetallic snap-action disc 18 then not only ensures the switching behavior, but also simultaneously generates the contact pressure between the movable contact part 22 and the stationary contact part 32 in the low-temperature position of the switch 100. The bimetallic snap-action disc 18 is then therefore used as a live component of the switching mechanism 10.

[0108] FIG. 3 shows a schematic sectional view of a second exemplary embodiment of the switch 100, In this regard, essentially the differences over the switch 100 according to the first exemplary embodiment shown in FIGS. 1 and 2 will be explained below. Since the general manner of operation of the switch 100 shown in FIG. 3 does not differ from the switch 100 shown in FIGS. 1 and 2, this is not explicitly addressed again.

[0109] One difference of the switch 100 shown in FIG. 3 according to the second exemplary embodiment resides in its even flatter design. In particular, the switching mechanism housing 16 is even flatter here. While that part of the second housing side 26 of the switching mechanism housing 16 which forms a freely accessible outside of the switch 10 comprises a domed portion 66 in FIG. 1, said part 68 of the switching mechanism housing 16 is pot-shaped according to the exemplary embodiment shown in FIG. 3. Said pot-shaped portion 68 comprises a flat contact surface 70 on its upper side, said contact surface being arranged in a plane E with a second contact surface 72 arranged on the switch housing 12. Said two contact surfaces 70, 72 are suitable for SMD mounting of the switch 100. The switch 100 can thus be mounted very easily upside down, as it were, on a flat printed circuit board.

[0110] The second contact surface 72, which is arranged on the surface of the switch housing 12, preferably completely surrounds the first contact surface 70 along the entire periphery of the switch 100. The first contact surface 70 is preferably circular. The second contact surface 72 is preferably configured in a circular ring shape.

[0111] Also in the switch interior, the switching mechanism housing 16 is flatter according to the second exemplary embodiment shown in FIG. 3. The base body 36 of the switching mechanism housing 16 is in turn integrally formed in one piece from an electrically conductive material, for example from metal. Also in this embodiment, the switching mechanism unit 14 is encapsulated in the switching mechanism housing 16. The switching mechanism housing 16 surrounds the switching mechanism unit 14 at least partially from all six spatial directions. The first housing side 24 of the switching mechanism housing 16 is in turn designed as a partially open housing side, which comprises a central opening 30 through which the movable contact part 22 directly interacts with the stationary contact part 32. In the low-temperature position of the switch 100 that is shown in FIGS. 1 and 3, the movable contact part 22 contacts the stationary contact part 32 through the opening 30.

[0112] The opening 30 is delimited in the radial direction by the base body 36 of the switching mechanism housing 16. On the first housing side 24, the base body 36 of the switching mechanism housing 16 comprises an inwardly folded-over, circumferential edge 74. Instead of such an edge 74, however, individual webs which protrude radially inwards from the housing circumferential side 28 may also be provided.

[0113] The edge 74 or the aforementioned webs serve as a counterholder for the bimetallic snap-action disc 18 according to the exemplary embodiment shown in FIG. 3. The edge 74 comprises a supporting surface 63, on which the bimetallic snap-action disc 18 can be supported in its high-temperature position.

[0114] In contrast to the first exemplary embodiment shown in FIGS. 1 and 2, the bimetallic snap-action disc 18 is no longer supported in its high-temperature position on the insulator 38, but rather on the base body 36 of the switching mechanism housing 16 itself, namely on the edge 74 or the aforementioned webs.

[0115] Another difference resides in the somewhat different design of the insulator 38. The insulator 38 is also configured here as an annular body, the outer circumferential surface of which abuts the inner circumferential surface of the switch housing 12. The insulator 38 is, however, approximately L-shaped in cross section here. The base body of the switching mechanism housing 16 rests on an inner circumferential shoulder 76 of the insulator 38.

[0116] Also according to this embodiment, it is preferred for the insulator 38, as part of the switching mechanism housing 16, to be inserted as a common unit into the switch housing 12 during the manufacturing of the switch 100. The insulator 38 is therefore also preferably connected here to the base body 36 of the switching mechanism housing 16. This connection can be made by means of one or more holding elements, for example at least one holding claw. Alternatively, the insulator 38 can be adhesively bonded, welded or soldered to the base body 36 of the switching mechanism housing 16.

[0117] FIGS. 4A-C schematically illustrate a plurality of working steps proceeding sequentially one after another in the installation of the switch 100 according to the first exemplary embodiment.

[0118] In a first installation step, the switching mechanism unit 14, which comprises the bimetallic snap-action disc 19, the snap-action spring disc 20 and the movable contact part 20, is inserted into the base body 36 of the switching mechanism housing 16 from below. The preformed base body 36 can be configured, for example, as a deep-drawn component. In FIG. 4A, the first housing side 25 is still completely open, and therefore the switching mechanism unit 14 can be easily inserted from below. A part of the housing circumferential side 28 as well as the second housing side 26 are designed as closed housing sides. From the housing circumferential side 28, a plurality of preformed holding claws 74 protrude perpendicularly downwards, approximately starting from the dashed line 78.

[0119] In a second assembly step, the insulator 38 is then pushed onto the holding claws 40. For this purpose, the insulator 38 preferably comprises a plurality of through bores 8 which are distributed over the circumference and through which the holding claws are inserted. The holding claws 40 are then folded over inwards, as indicated by the arrows 82, in order to fix the insulator 38 to the base body 36 of the switching mechanism housing 16. The switching mechanism 10 is therefore completed.

[0120] The completed switching mechanism 10, which can be stored as a semi-finished product in bulk material storage, is shown in the upper part of FIG. 4C. FIG. 5 shows a top view from below of the switching mechanism 10, as a result of which in particular the aforementioned manner of fastening the insulator 38 to the base body 36 of the switching mechanism housing 16 can be seen once again.

[0121] In the final installation step, which is shown in FIG. 4C, the switching mechanism 10, which is produced in advance as a semi-finished product, is inserted into the switch housing 12 and the switch housing 12 is closed by folding over of the upper edge 54 (see arrows 84).

[0122] As a final method step, not shown here, the insulating and sealing compound 58 is introduced into the intermediate space 56 between the switching mechanism housing 16 and the switch housing 12.