THERMAL CIRCUIT BREAKER

Abstract

A thermally activated safety switch for safeguarding a consumer of a power supply network of a vehicle, having a switch housing in a temperature-independent switching unit, which subject to the temperature thereof establishes an electrically conductive connection between two external terminals fed out of the switch housing, wherein the external terminals are fed out at opposite housing sides of the switch housing. On the one hand, the external terminals are provided for an electrical and mechanical terminal connection to the cable connection ends of a consumer to be protected, and on the other hand to a cable portion leading to an on-board power supply electronics, and are configured accordingly.

Claims

1. A thermally actuated circuit breaker for protecting a load, the circuit breaker comprising: a switch housing; a temperature-dependent switching mechanism arranged in the switch housing that subject to a temperature establishes an electrically conductive connection between two external terminals positioned on opposite sides of the housing and fed out of the switch housing; wherein the switch housing has a middle housing section surrounding the switching mechanism and an external housing section arranged on both sides for receiving the respective terminal connection, and wherein the two external terminals are arranged for electrical and mechanical connection with cable connection ends of a cable portion leading to a load of a vehicle power supply system to be protected and a cable portion leading to onboard electronics.

2. A thermally actuated circuit breaker according to claim 1, wherein the external terminals are fed out of the switch housing on housing narrow sides situated opposite each other in the housing longitudinal direction.

3. A thermally actuated circuit breaker according to claim 1, wherein the terminal connections are constructed as screwless connections with the cable connection ends.

4. A thermally actuated circuit breaker according to claim 1, wherein the external connections are constructed as crimp connections for the crimped connection of the cable ends.

5. A thermally actuated circuit breaker according to claim 1, wherein each terminal-side housing outer portion is formed of a housing lower part and a housing upper part closing the housing lower part.

6. A thermally actuated circuit breaker according to claim 5, wherein the upper housing part of the respective outer housing section is rotatably articulated in via a film hinge to the housing lower part.

7. A thermally actuated circuit breaker according to claim 1, wherein each terminal-side housing section provides a primary engagement of the respective terminal connection.

8. A thermally actuated circuit breaker according to claim 1, wherein each terminal-side housing section provides a secondary lock of the respective terminal connection for strain relief of the cable portion.

9. A thermally actuated circuit breaker according to claim 1, wherein the switching mechanism has a bimetal element supporting a movable contact on its free end and a switch contact point and a heating element in the form of a PTC resistor, which bears against the bimetal element and is supported by a spring element on a fixed contact arm, which supports a fixed contact that forms a switch contact point together with the movable contact.

10. A circuit breaker integrated in a vehicle power supply cable of a vehicle electrical system according to claim 1 for protecting a load of a vehicle power supply, wherein the external terminals are electrically and mechanically connected with a supply and electronics-side cable end and with a user or load-side cable end.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein:

[0025] FIG. 1 is a schematic longitudinal section of a thermally actuated circuit breaker with a thermally actuated switch mechanism and with external terminals diametrically extending in the switch longitudinal direction in their contact connection with cable connection ends (cable ends) from cable portions leading on the one side to onboard electronics and on the other, to a load,

[0026] FIG. 2 shows the thermal circuit breaker integratable into a cable according to FIG. 1, in a flat and miniature design with its diametrical external terminals in plan view,

[0027] FIG. 3 is a representation according to FIG. 2, the circuit breaker with a terminal connection of the cable ends designed as a crimp connection,

[0028] FIG. 4 is a partial perspective view of one of the external terminals of the circuit breaker in its configuration as a direct crimp connection,

[0029] FIG. 5 is a representation according to FIG. 4 of the connector configuration as a spring contact,

[0030] FIG. 6 shows the connector configuration as a cage clamp spring,

[0031] FIG. 7 shows the connector configuration as a spring-loaded terminal,

[0032] FIG. 8 shows the connector configuration as a double-edged insulation displacement contact,

[0033] FIG. 9 is a perspective view of the circuit breaker integrated in the cable with a switch housing formed by three housing sections,

[0034] FIG. 10 is a perspective view of the cable-integrated circuit breaker with open terminal-side housing sections and a closed middle housing section,

[0035] FIG. 11 shows the arrangement of FIG. 10 with closed terminal-side housing sections,

[0036] FIG. 12 shows an excerpt of one of the terminal-side housing sections according to a variant with a closed and an open housing section, and

[0037] FIG. 13 shows the terminal-side housing structure according to FIG. 12 in longitudinal section with primary engagement of the cable end and having a secondary lock for strain relief when the housing part is closed.

DETAILED DESCRIPTION

[0038] FIG. 1 schematically shows a cable-integratable, thermally actuated circuit breaker 1 in its electrically contacted and mechanical connection, with a (first) cable portion 3a leading to an onboard electronics 2 of a motor vehicle, and a second cable portion 3b of an onboard power supply cable or cable harness 3 leading to an electrical load or an electric load 4. The first cable portion 3a is hereinafter referred to as the control or supply-side cable portion and the second cable portion 3b is called the user or load-side cable portion.

[0039] The load 4 may be, for example, an electric motor driven actuator or other conventional electrical load of a vehicle (car, truck).

[0040] The thermal, i.e., thermally actuated circuit breaker 1 includes a switch housing 5 which is suitably designed in as flat a construction as possible. The thus miniaturized circuit breaker 1 is suitably designed to be self-resetting and for this purpose, within the housing includes a switching mechanism 6 with a, for example, strip-shaped bimetal element 7 and a switch contact point 8 and a heating element 9 in the form of a PTC resistor which rests on the bimetal element 7 and is supported by a spring element 10 on a fixed contact arm 11 that supports a fixed contact 8a on its free end. The bimetal 7 supports a movable contact 8b on its free end, which, together with the fixed contactor 8a, forms the contact point 8 of the circuit breaker 1 shown in the closed position. The bimetal element 7 is electrically and mechanically connected with a movable contact arm 13 by its bimetallic end 12 situated opposite the contact point 8.

[0041] The fixed contact arm 11 and the movable contact arm 13 are designed as flat contacts as well as suitably power rail-like, and for this purpose, expediently designed as a stamped bent part. The contact arms 11 and 13 are fed out from the switch housing 5 on the end side in the housing longitudinal direction 14 on opposite narrow housing sides 5a and 5b and there, form the external terminals 15a, 15b. These are provided and arranged for electrical and mechanical connections 16a and 16b, with cable ends 17a, 17b of the supply-side cable portion 3a and the load-side cable portion 3b. The connections 16a, 16b are suitably situated in terminal-side housing sections 51 and 52 of, for example, a middle housing section 53, in particular, as a plastic injection molded part.

[0042] The operation of the thermal circuit breaker 1 corresponds practically to that of a thermally actuated circuit breaker known per se from WO 2012/037991 A1, in which in case of an overcurrent, the breaker flows through the bimetal element 7 in the closed position of the contact point 8 and flexes the element as a result of its deflection in the tripping direction 18. Thereby, the movable contact 8b is lifted from the fixed contact 8a and thereby pivoted in the direction of the movable contact arm 13. The current interruption thus caused, that is, the interruption of the circuit closed via the contact point 8 in the closed state of the contacts 8a, 8b of the contact point, would result in a cooling of the bimetal element 7 and, consequently, lead to a reclosing of the contact point 8. To prevent this, the suitably high-impedance-designed heating element 9 is also electrically connected to the power rail-like contact arms 11, 13 when the contact point 8 is open and thus energized. Due to the resulting heat build-up, a cooling of the bimetal element 7 adequate for renewed closing of the contact point 8 is avoided. The spring element 10 serves substantially to apply a sufficient pressing force of the heating element 9 designed as a PTC resistor to the bimetal element 7.

[0043] FIG. 2 also shows the circuit breaker 1 in a plan view, with external terminals 15a and 15b diametrically extending in the longitudinal direction of the switch 14. The terminal connection 16a, 16b of the circuit breaker 1 with the cable portions 3a and 3b of the cable 3 or with its cable ends 17a, 17band in this respect with its cable or conductor coresis suitably carried out without screws. For this purpose, several variants of suitable terminal connections are exemplified in FIGS. 3 to 8.

[0044] In the embodiments according to FIGS. 3 and 4, the connections 16a, 16b between the external terminals 15a, 15b of the circuit breaker 1 and the cable connection ends 17a and 17b are designed as crimp connections. In the embodiment of FIG. 4, a corresponding crimp sleeve 19 is suitably already mounted directly contacting the respective external terminal 15a, 15b of the circuit breaker 1. Also, the respective external terminal 15a, 15b may already be designed as such a crimp sleeve 19.

[0045] In the embodiment of FIG. 5, the respective terminal connection 16a, 16b is designed as a double spring contact with a corresponding spring terminal 20, which is in turn suitably connected mechanically and electrically conductive by means of a crimp connection to the corresponding cable end 3a, 3b.

[0046] FIGS. 6 and 7 show terminal connections 16a, 16b designed as spring-loaded terminals, wherein in the embodiment of FIG. 6, a cage clamp spring 21a is provided, and in the embodiment of FIG. 7, a so-called push-in spring 21b is provided. Relatively clearly visible in FIGS. 6 and 7 are the stripped conductor cores of the cable ends 17a, 17b of the cable portions 3a and 3b.

[0047] FIG. 8 shows a connection variant of the connections 16a, 16b with a double-edged IDC 22. In this case, both blades 22a, 22b of the insulation displacement contact 22 for making electrical contact, or one of the two cutting edges 22a, 22b, can serve as a pure strain relief.

[0048] FIGS. 9 to 11 show embodiments of the switch housing 5 of the thermal circuit breaker 1 formed by the terminal-side housing sections 51 and 52 and the middle housing section 53. In the embodiment of FIG. 9, the terminal-side housing sections 51, 52 are designed as closed housing parts, in which the switch-side external terminals 15a, 15b are arranged and the connections 16a, 16b are made with the cable ends 17a and 17b, respectively.

[0049] The embodiments of FIGS. 10 and 11 show two-piece, terminal-side housing sections 51, 52 in the open or closed state with housing lower parts 51 a, 52a firmly attached to the middle housing section 53 of the switch housing 5 and with a housing upper part 51b and 52b hinged thereto via a film hinge 51c, 52c. In the embodiment shown, the connections 16a, 16b are constructed as double spring contacts according to the variant of FIG. 5.

[0050] Locking elements 23, 24 are molded at the housing upper parts 51b, 52b of the terminal-side housing sections 51, 52, which engage in corresponding latching elements 25 and 26 molded on each housing part 51a, 52a by forming undercuts.

[0051] In a perspective view and in a longitudinal section, FIGS. 12 and 13 show a terminal-side housing section 51, 52 divided in the adjacent region with a closed housing section 27 and a closable housing section 28, which in turn has a cover part 30 articulated via a film hinge 29. Cable-side locking elements 31a, 31b on the cover part 30 and on a bottom-side housing section area 32 in turn enable a reliable closing of the open housing section 28 by means of a locking connection in which the cover-side locking element 31 a undercuts the housing-side locking element 31b.

[0052] As can be relatively clearly seen in FIG. 13, in the embodiment, the terminal connection 16a, 16b is in turn designed as a double spring contact. When the cover part 30 is still open, the terminal connection 16a, 16b is produced by plugging on or plugging in a corresponding spring contact 33 on the respective external terminal 15a, 15b. The terminal connection 16a, 16b is thereby fixed by a primary engagement 34 in that spring tongues 36 of the spring contact 33 placed in the plug-in direction 35 engage behind housing-side locking contours 37. Additionally, a secondary lock 38 is provided for strain relief of the respective cable portion 3a, 3b. This is formed on the cover part (cover-side housing part) 30 by a corresponding locking contour 39 (FIG. 12) that is molded inwardly to the respective terminal connection 16a, 16b on the inside of the cover.

[0053] Due to the practically streamlined geometry and the relatively small mass of the thermal circuit breaker 1, it is possible to integrate the breaker without a separate attachment directly in the cable harness or in the onboard power supply cable 3 in an electrically contacting and mechanically reliable manner, firmly fastened, and thus integrate it in the cable 3 in a particularly space-saving manner.

[0054] The invention is not limited to the embodiments described above. Rather, other variations of the invention can be derived therefrom by those skilled in the art without departing from the scope of the invention. In particular, further, all single features described in connection with the embodiments can be combined in other ways without departing from the scope of the invention.

[0055] For example, the terminal connections 16a, 16b with the two external terminals 15a and 15b of the thermal circuit breaker 1 may be designed as different, screwless plug connections in accordance with the variations in FIGS. 3 to 8. Also, only one of the terminal-side housing sections 51, 52 of the switch housing 5 may be designed closable (FIG. 10) or partially closeable (FIG. 12) whereas the opposite terminal-side housing section 52 or 51 may be designed closed. Furthermore, the supply-side terminal connection 16a and/or the load-side terminal connection 16b may be designed as a welded connection.

[0056] The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.