Active / Passive Fuse Module

Abstract

To provide a fuse module equipped with both passive and active circuit protection elements for specific applications such as automobile applications.SOLUTION: An active / passive fuse module includes a fuse having an arc quenching material disposed within a fuse body and surrounding a fusible element. The fuse module further includes a pyrotechnic interrupter (PI) coupled to the fuse body. The PI has: a housing defining a shaft; a piston disposed within the shaft; a drive pin extending from the piston into the fuse body, the drive pin terminating in a cutter disposed adjacently to the fusible element; and a pyrotechnic ignitor disposed within the shaft above the piston configured to detonate upon receiving an initiation signal from a controller, so that the piston and the drive pin are forcibly driven through the shaft causing the cutter to separate the fusible element.SELECTED DRAWING: Figure 1A

Description

Technical Field

[0001] [Cross - Reference to Related Applications] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 389,154, filed on July 14, 2022, which is hereby incorporated by reference in its entirety.

[0002] The present disclosure generally relates to the field of circuit protection devices, and more specifically, to an active / passive fuse module that includes both passive and active circuit protection elements.

Background Art

[0003] Fuses are typically implemented in electrical systems to provide over - current protection. Most fuses are "passive" devices that include a fuse element configured to carry a rated current amount in normal operation. When the current flowing through the fuse element exceeds the rated current value of the fuse element, the fuse element melts, decomposes, or separates in some other way, thereby blocking the current and preventing or reducing damage to the connected electrical components.

[0004] In some cases, such as for automotive applications, it may be desirable to "actively" create a physical open state in an electrical circuit regardless of the amount of current flowing through the circuit. For example, when a vehicle is involved in a collision, it may be desirable to physically open the vehicle's electrical circuit to cut off the power to the connected electrical components and ensure that the risk of fire and / or electric shock that may occur following the collision is reduced. For this purpose, so-called pyrotechnic current interrupters (PIs) have been developed, which can selectively operate when a specific event occurs to cut off the current flowing through the circuit. For example, when a vehicle collides, a controller (e.g., an airbag control unit, a battery management system, etc.) may send an activation signal to the PI to detonate the pyrotechnic igniter within the PI. As a result, when the pressure within the PI increases, a conductor (e.g., a bus bar) extending through the PI is immediately cut off by a piston or a blade. Thereby, the current flowing through the PI is interrupted, and the piston formed of a dielectric material provides an electrically insulating barrier between the separated portions of the conductor to prevent an electric arc from occurring between them.

[0005] In certain applications, it may be desirable to implement both passive and active circuit protection elements. Further, it may be desirable to implement such elements in a small, space-saving form factor that facilitates easy installation.

[0006] This improvement may be useful in connection with these and other considerations. SUMMARY OF THE INVENTION

[0007] This summary is provided to introduce, in a simplified form, a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is this summary intended to be used as an aid in determining the scope of the claimed subject matter.

[0008] An active / passive fuse module according to a non-limiting embodiment of the present disclosure can include a fuse having an electrically insulating fuse body, a first end cap and a second end cap disposed at both ends of the fuse body, a soluble element extending through the fuse body between the first end cap and the second end cap, and an arc extinguishing material disposed inside the fuse body and surrounding the soluble element. The fuse module can further include a pyrotechnic current interrupter (PI) coupled to the fuse body, where the PI includes a housing defining a shaft, a piston disposed inside the shaft, a drive pin extending from the piston to the fuse body, where the drive pin terminates at a cutter disposed adjacent to the soluble element, and a pyrotechnic igniter disposed inside the shaft above the piston configured to detonate when receiving an activation signal from a controller, whereby the piston and the drive pin are forced to drive through the shaft to separate the soluble element from the cutter.

[0009] Another active / passive fuse module according to a non-limiting embodiment of the present disclosure can include a fuse having an electrically insulating fuse body, a first end cap and a second end cap disposed at both ends of the fuse body, and a plurality of soluble elements extending through the fuse body between the first end cap and the second end cap. The fuse module can further include a pyrotechnic current interrupter (PI) coupled to the fuse body, where the PI includes a housing defining a shaft, a piston disposed inside the shaft, a drive pin extending from the piston to the fuse body, where the drive pin terminates at a cutter, where at least one of the plurality of soluble elements extends through each through hole in the cutter, where the lower edge of the cutter is disposed above at least another one of the plurality of soluble elements, and a pyrotechnic igniter disposed inside the shaft above the piston configured to detonate when receiving an activation signal from a controller, whereby the piston and the drive pin are forced to drive through the shaft to separate the plurality of soluble elements from the cutter.

Brief Description of the Drawings

[0010]

Figure 1A

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Figure 1B

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Figure 2

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Figure 3A

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Figure 3B

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Figure 4A

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Figure 4B

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Figure 5A

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Figure 5B

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Figure 6

[0020] The active / passive fuse module according to the present disclosure will now be described in more detail with reference to the accompanying drawings. The accompanying drawings show preferred embodiments of the active / passive fuse module. However, it will be understood that the active / passive fuse module may be embodied in many different forms and should not be construed as limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will convey to those skilled in the art a particular exemplary aspect of the active / passive fuse module.

[0021] Referring to FIGS. 1A and 1B, a cutaway side view and a cross-sectional view with the end facing forward are shown, respectively, showing an active / passive fuse module 10 (hereinafter "fuse module 10") according to an exemplary and non-limiting embodiment of the present disclosure. For convenience and clarity, terms such as "front", "rear", "upper", "lower", "above", "below", "vertical", "horizontal", "lateral", and "longitudinal" may be used herein to describe the relative placement and orientation of the various components of the fuse module 10, each of which relates to the geometry and orientation of the fuse module 10 as seen in FIGS. 1A and 1B. The above terms will be understood to include the specifically recited words, their derivatives, and synonyms.

[0022] As will be further described below, the fuse module 10 can generally include a fuse 12 and a pyrotechnic current interrupter (PI) 13 coupled to each other. In various embodiments, the fuse 12 can be a cartridge fuse having a tubular fuse body 14. The present disclosure is not limited in this regard. In various alternative embodiments, the fuse 12 can be a surface mount fuse or other type of fuse having a soluble element extending through a generally hollow fuse body. The fuse body 14 can be formed of an electrically insulating and preferably heat-resistant material. Examples of such materials include, but are not limited to, ceramics and glass.

[0023] A first end cap 18 and a second end cap 20 can be disposed at both ends of the fuse body 14. The soluble element 24 can extend through the hollow interior of the fuse body 14 between the first end cap 18 and the second end cap 20. In various embodiments, the end caps 18, 20 can be formed of a conductive material (such as copper, tin, various alloys, etc.), and the soluble element 24 can be connected to the end caps 18, 20 by solder or the like. Thus, the first end cap and the second end cap can facilitate the electrical connection of the fuse module 10 in the circuit. Alternatively, the first end cap 18 and the second end cap 20 can be formed of a dielectric material (such as plastic), and the soluble element 24 can extend through and protrude from the first end cap 18 and the second end cap 20 (as shown in FIG. 1A), and the protruding ends of the soluble element 24 can facilitate the electrical connection of the fuse module 10 in the circuit. The soluble element 24 can be formed of a conductive material including, but not limited to, tin or copper, and can be configured to melt and separate when a predetermined fault condition occurs, such as an overcurrent condition where a current amount exceeding a predetermined maximum value flows through the soluble element 24. This maximum value is usually referred to as the "rated current" of the fuse 12. In various embodiments, the soluble element 24 can be configured to facilitate a rated current in the range between 30 amperes and 1000 amperes. The present disclosure is not limited in this regard.

[0024] The soluble element 24 can be any type of soluble element suitable for the desired application, including but not limited to wires, strips, wires wound around an insulating core, etc. In various embodiments, the central portion of the soluble element 24, hereinafter referred to as the "bridge portion 25", may be made thinner, narrower, perforated, or otherwise weakened compared to other portions of the soluble element 24 to ensure that the soluble element 24 separates at the bridge portion 25 when the fuse rating is exceeded. The present disclosure is not limited in this regard.

[0025] The interior of the fuse body 14 can be partially or entirely filled with an arc extinguishing material or "fuse filler" 26 that can surround the soluble element 24. The arc extinguishing material 26 may be provided to reduce the electrical arc that spans the separated portions of the soluble element 24 after the soluble element 24 has separated (e.g., upon the occurrence of an overcurrent condition in the fuse 12), thereby further increasing the interrupting capacity of the fuse 12. As will be further described below, the arc extinguishing material 26 can additionally provide mechanical support to the soluble element 24. Arc extinguishing materials that can be used in the fuse 12 include, but are not limited to, sand, silica, etc.

[0026] PI13 can include a housing 30 formed of an electrically insulating material such as plastic, polymer, ceramic, etc. The housing 30 can have an upper portion 32 that houses the circuit breaker assembly 34 and a lower portion 36 that is clamped to the fuse body 14 of the fuse 12. For example, as best shown in FIG. 1B, the lower portion 36 of the housing 30 can generally include a semi-circular upper half 38 and a generally semi-circular lower half 40. The semi-circular upper half 38 and the generally semi-circular lower half 40 can be fastened to each other by mechanical fasteners (such as screws) by extending through flanges extending from the upper half 38 and the lower half 40 of the lower portion 36, as shown. The present disclosure is not limited in this regard. When fastened in this way, the lower portion 36, which can have an inner diameter that is approximately equal to but slightly larger than the outer diameter of the fuse body 14, can clamp the fuse body 14 in a relationship with little radial clearance with the fuse body 14 and can surround the fuse body 14.

[0027] The circuit breaker assembly 34 can include a movable piston 42 disposed within a vertically extending hollow shaft 44 positioned over the fuse body 14. The circuit breaker assembly 34 can further include a pyrotechnic igniter 46 disposed within the shaft 44 above the piston 42, and a drive pin 48 extending from the lower portion of the piston 42. The drive pin 48 can extend through a through hole 49 into the fuse body 14 and can terminate at a cutter 50 positioned directly above the soluble element 24. The drive pin 48 can be formed of steel or other similarly hard and rugged material. In various embodiments, the cutter 50 can be formed of ceramic or other similarly hard and rugged dielectric material with low arc tracking. Alternatively, the cutter 50 can be formed of a conductive material such as metal. The present disclosure is not limited in this regard. The tip of the cutter 50 may be pointed as shown in FIG. 1A, but this is not essential. In various embodiments, the tip of the cutter 50 may be attached or fixed to the soluble element 24 (e.g., by an adhesive, press fit, detent, etc.) to fix the position of the cutter 50 relative to the soluble element 24. The present disclosure is not limited in this regard. The lower edge of the piston 42 may be concave and may have a radius of curvature substantially equal to the radius of curvature of the exterior of the fuse body 14 as shown in FIG. 1B, but this is also not essential.

[0028] The pyrotechnic igniter 46 may be coupled to a controller 52 (e.g., an airbag control unit of a motor vehicle, a battery management system, etc.). When a predetermined event such as a collision of a motor vehicle occurs (i.e., when the fuse module 10 is implemented in a motor vehicle), the controller 52 can send an activation signal to the pyrotechnic igniter 46 to detonate the pyrotechnic igniter 46. As shown in FIG. 2, as a result, when the pressure increases within the shaft 44 above the piston 42, the piston 42 and the drive pin 48 are immediately pushed downward through the shaft 44 to cause the cutter 50 to cut the soluble element 24. Thereby, the current flowing through the soluble element 24 is interrupted. When the cutter is formed of a dielectric material, the cutter 50 can provide an electrical insulating barrier between the separated portions of the soluble element 24 to prevent an electric arc therebetween. Also, when the soluble element 24 is cut by the cutter 50, an arc that has already started but has not yet self-extinguished can be extended, thereby increasing the arc voltage to facilitate a more rapid interruption. Alternatively, when the cutter 50 is formed of a conductive material, the cutter 50 functions to split an arc that has already started, thereby increasing the overall arc voltage and contributing to a more rapid interruption of the arc.

[0029] The arc extinguishing material 26 (e.g., sand) surrounding the soluble element 24 can provide mechanical support to the soluble element 24, which is advantageous because it can firmly hold the soluble element 24 in place when it engages the cutter 50. This facilitates cleanly and completely cutting the soluble element 24, whereas if the soluble element 24 were simply surrounded by air, the soluble element 24 would tend to be pushed aside by the cutter 50, be partially cut, or simply bent. This eliminates the need for special structural features extending from the fuse body 14 to support the soluble element 24, which can sometimes be seen in conventional pyro fuse modules.

[0030] In view of the above description, it will be appreciated that the fuse module of the present disclosure facilitates both "active" (i.e., by the controller 52 sending an activation signal to the pyrotechnic igniter 46 when a collision occurs, etc.) triggering and "passive" (i.e., by the soluble element 24 melting / separating when exposed to a current exceeding the rated current of the fuse 12) triggering. This provides a number of advantages. For example, the arc extinguishing material 26 surrounding the soluble element 24 allows the fuse module 10 to passively interrupt very large currents (e.g., greater than 20 kA) without being destroyed or causing an electrical arc of an unacceptable duration. Additionally, the PI 13 can be actuated to interrupt the circuit at any time regardless of the amount of current flowing through the fuse module 10. For example, if the vehicle experiences a collision while parked, the pyrotechnic igniter 46 may be actuated to disconnect the vehicle battery from the vehicle's electrical system, even if the current through the fuse module 10 is zero. Additionally, when operating at medium to high currents where the fuse 12 may open the circuit too slowly passively, the pyrotechnic igniter 46 may be actuated to open the circuit much more quickly. Further, even after the soluble element 24 has melted / separated upon the occurrence of an overcurrent condition (i.e., after passive triggering of the fuse module 10), the pyrotechnic igniter 46 is actuated to improve / ensure complete separation and galvanic insulation at the soluble element 24, thereby increasing the resistance in the open state and reducing or eliminating leakage current.

[0031] The fuse module 10 has been shown and described above as having a cutter 50 configured to directly sever the bridge portion 25 of the soluble element 24. On the other hand, an alternative embodiment of the fuse module 10 is contemplated in which the cutter 50 is adapted to indirectly separate the soluble element 24 at a plurality of bridge portions. For example, referring to FIG. 3A, the soluble element 24 can include a first bridge portion 25a and a second bridge portion 25b separated by an intermediate portion 27 spanning therebetween. The first bridge portion 25a and the second bridge portion 25b may be thinner, thinner, or otherwise mechanically weaker than the intermediate portion 27. The intermediate portion may be aligned with the cutter 50 (e.g., positioned directly below the cutter 50), and the first bridge portion 25a and the second bridge portion 25b may be offset from the cutter 50 (e.g., positioned on both sides of the cutter 50). When the pyrotechnic igniter 46 is detonated as shown in FIG. 3B, the cutter 50 is driven into the intermediate portion 27 and presses the intermediate portion 27 downward, and such force can tear, break, or otherwise separate the soluble element 24 at the mechanically weaker bridge portions 25a, 25b. That is, the intermediate portion 27 that directly engages the cutter 50 remains undamaged (although it may deform as shown). On the other hand, the bridge portions 25a, 25b are torn, broken, or otherwise separated. As explained above, the current flowing through the soluble element 24 is thereby interrupted. In the embodiments of FIGS. 3A and 3B, since it is not necessary or desirable for the cutter 50 to cut or separate the intermediate portion 27, it may be desirable for the tip of the cutter 50 to be rounded, squared, or otherwise blunted.

[0032] Referring to FIG. 4A, yet another embodiment of the fuse module 10 described above is shown. The embodiment of FIG. 4A may be substantially the same as the embodiments of FIGS. 1A and 1B, but may further include a crush rib 54. The crush rib 54 may be a post or strut formed of a relatively low density material (such as silicone foam or a similar material) that is aligned with the cutter 50 and extends from the lower portion of the soluble element 24 to or near the inner surface of the fuse body 14. The purpose of the crush rib 54 is to partially or entirely fill the space directly below the cutter 50 and the soluble element 24 and prevent the arc extinguishing material 26 from fitting into this space. Thus, the crush rib 54 provides a medium having a lower mechanical resistance than the arc extinguishing material and through which the cutter 50 can pass when the pyrotechnic igniter 46 detonates as shown in FIG. 4B. Thus, it is ensured that the cutter 50 can cleanly and immediately separate the soluble element 24 without significant interference.

[0033] Referring to FIGS. 5A and 5B, a cutaway side view and a cross-sectional view with the end facing forward are shown, respectively, depicting another active / passive fuse module 100 (hereinafter "fuse module 100") according to an exemplary and non-limiting embodiment of the present disclosure. Fuse module 100 may be substantially similar to fuse module 10 described above, but may include a plurality of soluble elements 124a, 124b spaced apart in the vertical direction. Two soluble elements 124a, 124b (hereinafter "first soluble element 124a" and "second soluble element 124b") are depicted, but a greater number of soluble elements may be implemented without departing from the scope of the present disclosure. A greater number of soluble elements can provide greater current handling performance by fuse module 100. Also, soluble elements 124a, 124b are shown as being oriented parallel to each other. However, this is not essential. As shown in FIG. 5B, each of the first soluble element 124a and the second soluble element 124b can include a plurality of bridge sections 127, 129 separated by gaps. Bridge sections 127, 129 may be relatively thinner than other portions of the first soluble element 124a and the second soluble element 124b, and thus may be adapted to melt and separate upon the occurrence of an overcurrent condition in fuse module 100. Each of the first soluble element 124a and the second soluble element 124b is depicted as having four bridge sections 127, 129, but this is not intended to be limiting. Without departing from the present disclosure, soluble elements having a greater or lesser number of bridge sections may be implemented.

[0034] The fuse module 100 can include a multi-level cutter 150 having a through hole 151 formed therein. The first soluble element 124a can extend through the through hole 151. The upper edge of the through hole 151 can define a first blade 153a disposed on the first soluble element 124a. The lower edge of the cutter 150 can define a second blade 153b disposed on the second soluble element 124b. Thus, when the pyrotechnic igniter 146 is actuated, the cutter 150 can simultaneously cut and separate the first soluble element 124a and the second soluble element 124b. Although not shown in FIGS. 5A and 5B, it will be appreciated that the fuse module 100 may additionally include a crush rib (similar to the crush rib 54 described above) disposed under the second soluble element 124b and aligned with the cutter 150. The present disclosure is not limited in this regard.

[0035] Referring to FIG. 6, a cut-away side view is shown of another active / passive fuse module 200 (hereinafter fuse module 200) according to an exemplary and non-limiting embodiment of the present disclosure. The fuse module 200 may be substantially similar to the fuse module 100 described above, but can include a plurality of parallel, horizontally spaced cutters 250a, 250b, 250c. The cutters 250a, 250b, 250c may be substantially identical to the cutter 150 described above and can be adapted to simultaneously cut the soluble elements 224a, 224b at a number of locations along their lengths. Although three cutters 250a, 250b, 250c are depicted, more or fewer parallel cutters may be implemented without departing from the scope of the present disclosure. A greater number of cutters can provide a greater interrupting capacity for the fuse module 200.

[0036] As used herein, an element or step recited in the singular and preceded by the word "a" or "an" should be understood as not excluding a plurality of elements or steps, unless such exclusion is explicitly recited. Further, reference to "one embodiment" of the present disclosure is not intended to be construed as excluding the existence of additional embodiments that also incorporate the recited features.

[0037] The present disclosure refers to specific embodiments. On the other hand, numerous modifications, alterations, and changes can be made to the described embodiments without departing from the scope and range of the present disclosure as defined in the appended claims. Accordingly, the present disclosure is not intended to be limited to the described embodiments, but rather is intended to have the full scope defined by the language of the following claims and their equivalents.

Claims

1. A fuse, comprising: an electrically insulating fuse body; a first end cap and a second end cap disposed at both ends of the fuse body; a soluble element extending through the fuse body between the first end cap and the second end cap; an arc extinguishing material disposed inside the fuse body surrounding the soluble element to provide mechanical support for the soluble element and hold the soluble element in a fixed position; and a pyrotechnic current interrupter (PI) coupled to the fuse body, the PI comprising: a housing defining a shaft; a piston disposed inside the shaft; a drive pin extending from the piston to the fuse body and terminating at a cutter disposed adjacent to the soluble element; a pyrotechnic igniter disposed above the piston inside the shaft, the pyrotechnic igniter configured to detonate when receiving an activation signal from a controller, thereby driving the piston and the drive pin forcefully through the shaft to separate the soluble element from the cutter; and a crash rib disposed below the soluble element and aligned with the cutter, the crash rib at least partially filling a space directly below the cutter and the soluble element to prevent the arc extinguishing material from fitting into the space, the crash rib being a medium having a lower mechanical resistance than the arc extinguishing material and allowing the cutter to pass through when the PI detonates, an active / passive fuse module.

2. The active / passive fuse module according to claim 1, wherein the soluble element includes a bridge portion that is mechanically weaker than a portion surrounding the soluble element, and the cutter is configured to be aligned with the bridge portion and directly pass through the bridge portion upon detonation of the PI.

3. The active / passive fuse module according to claim 2, wherein a tip of the cutter is sharp.

4. The soluble element includes an intermediate portion spanning between a first bridge portion and a second bridge portion, the first bridge portion and the second bridge portion being mechanically weaker than the intermediate portion, the cutter being aligned with the intermediate portion and configured to directly engage the intermediate portion upon detonation of the PI to separate the soluble element at the first bridge portion and the second bridge portion. The active / passive fuse module according to claim 1.

5. The tip of the cutter is blunt. The active / passive fuse module according to claim 4.

6. The cutter is formed of a dielectric material. The active / passive fuse module according to claim 1.

7. The cutter is formed of a conductive material. The active / passive fuse module according to claim 1.

8. The housing of the PI is clamped to the fuse body of the fuse. The active / passive fuse module according to claim 1.

9. The tip of the cutter is fastened to the soluble element to fix the position of the cutter relative to the soluble element. The active / passive fuse module according to claim 1.

10. The crush rib is formed of a silicone foam. The active / passive fuse module according to claim 1.

11. A fuse, comprising an electrically insulating fuse body, a first end cap and a second end cap disposed at both ends of the fuse body, a plurality of soluble elements extending through the fuse body between the first end cap and the second end cap, and a pyrotechnic current interrupter (PI) coupled to the fuse body, the PI comprising a housing defining a shaft, a piston disposed inside the shaft, a drive pin extending from the piston to the fuse body and terminating in a cutter, at least one of the plurality of soluble elements extending through each through hole in the cutter, and a lower edge of the cutter being disposed above at least another one of the plurality of soluble elements. A drive pin. An active / passive fuse module having a pyrotechnic igniter disposed above the piston inside the shaft, the pyrotechnic igniter being configured to detonate upon receiving an activation signal from a controller, thereby driving the piston and the drive pin forcefully through the shaft to separate the plurality of soluble elements at the cutter.

12. The active / passive fuse module according to claim 11, wherein each of the plurality of soluble elements has a plurality of bridge sections that are parallel to each other and mechanically weaker than portions surrounding the plurality of soluble elements, and the cutter is aligned with the plurality of bridge sections and configured to directly pass through the plurality of bridge sections upon detonation of the PI.

13. The active / passive fuse module according to claim 11, wherein the cutter is formed of a dielectric material.

14. The active / passive fuse module according to claim 11, wherein the cutter is formed of a conductive material.

15. The active / passive fuse module according to claim 11, wherein the cutter is fastened to at least one of the plurality of soluble elements to fix the position of the cutter relative to the plurality of soluble elements.

16. The active / passive fuse module according to claim 11, further comprising an arc extinguishing material disposed inside the fuse body and surrounding the plurality of soluble elements.

17. The active / passive fuse module according to claim 16, further comprising a crush rib disposed below the plurality of soluble elements and aligned with the cutter, the crush rib at least partially filling a space directly below the cutter and the plurality of soluble elements to prevent the arc extinguishing material from fitting into the space, the crush rib being a medium having a lower mechanical resistance than the arc extinguishing material and providing the medium through which the cutter can pass when the PI detonates.

18. The active / passive fuse module according to claim 17, wherein the crush rib is formed of a silicone foam.

19. The cutter includes a plurality of cutters spaced apart from each other along the length of the plurality of soluble elements, and the plurality of cutters are configured to separate the plurality of soluble elements at various points along the length of the plurality of soluble elements when the PI detonates. The active / passive fuse module according to any one of claims 11 to 18.

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