This disclosure relates generally to the field of circuit protection devices and relates more particularly to an active/passive fuse module that includes both passive and active circuit protection elements.
Fuses are commonly implemented in electrical systems for providing overcurrent protection. Most fuses are “passive” devices that include fuse elements that are configured to carry a rated amount of electrical current during normal operation. If current flowing through a fuse element exceeds the fuse element's rated current, the fuse element will melt, disintegrate, or otherwise separate, thereby arresting the current to prevent or mitigate damage to connected electrical components.
In some cases, such as in automobile applications, it may be desirable to “actively” create a physical opening in an electrical circuit regardless of an amount of electrical current flowing through the circuit. For example, if an automobile is involved in a collision, it may be desirable to physically open an electrical circuit in the automobile to ensure that connected electrical components are deenergized to mitigate the risk of fire and/or electrocution in the aftermath of the collision. To that end, so-called pyrotechnic interrupters (PIs) have been developed which can be selectively actuated upon the occurrence of specified events to interrupt the flow of current in a circuit. For example, in the case of an automobile collision, a controller (e.g., an airbag control unit, battery management system, etc.) may send an initiation signal to a PI, causing a pyrotechnic ignitor within the PI to be detonated. A resultant increase in pressure within the PI rapidly forces a piston or blade through a conductor (e.g., a bus bar) that extends through the PI. Electrical current flowing through the PI is thereby interrupted, and the piston, which is formed of a dielectric material, provides an electrically insulating barrier between separated portions of the conductor to prevent electrical arcing therebetween.
In certain applications it may be desirable to implement both passive and active circuit protection elements. It may further be desirable to implement such elements in a compact, space-saving form factor that facilitates convenient installation.
It is with respect to these and other considerations that the present improvements may be useful
This Summary is provided to introduce a selection of concepts in a simplified form 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 the summary intended as an aid in determining the scope of the claimed subject matter.
An active/passive fuse module in accordance with a non-limiting embodiment of the present disclosure may include a fuse having an electrically insulating fuse body, first and second endcaps disposed on opposing ends of the fuse body, a fusible element extending through the fuse body between the first endcap and the second endcap, and an arc quenching material disposed within the fuse body and surrounding the fusible element. The fuse module may further include a pyrotechnic interrupter (PI) coupled to the fuse body, the PI having 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 adjacent 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, whereby the piston and the drive pin are forcibly driven through the shaft causing the cutter to separate the fusible element.
Another active/passive fuse module in accordance with a non-limiting embodiment of the present disclosure may include a fuse having an electrically insulating fuse body, first and second endcaps disposed on opposing ends of the fuse body, and a plurality of fusible elements extending through the fuse body between the first endcap and the second endcap. The fuse module may further include a pyrotechnic interrupter (PI) coupled to the fuse body, the PI having 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, wherein at least one of the plurality of fusible elements extends through a respective through hole in the cutter and wherein a bottom edge of the cutter is disposed above at least another one of the plurality of fusible elements, and a pyrotechnic ignitor disposed within the shaft above the piston configured to detonate upon receiving an initiation signal from a controller, whereby the piston and the drive pin are forcibly driven through the shaft causing the cutter to separate the plurality of fusible elements.
An active/passive fuse module in accordance with the present disclosure will now be described more fully with reference to the accompanying drawings, in which preferred embodiments of the active/passive fuse module are presented. It will be understood, however, that the active/passive fuse module may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will convey certain exemplary aspects of the active/passive fuse module to those skilled in the art.
Referring to
The fuse module 10 may generally include a fuse 12 and a pyrotechnic interrupter (PI) 13 coupled to one another as further described below. In various embodiments, the fuse 12 may 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 may be a surface mount fuse or other type of fuse having a fusible element extending through a generally hollow fuse body. The fuse body 14 may be formed of an electrically insulating and preferably heat resistant material. Examples of such materials include, but are not limited to, ceramic and glass.
First and second endcaps 18, 20 may be disposed on opposing ends of the fuse body 14. A fusible element 24 may extend through the hollow interior of the fuse body 14 between the first and second endcaps 18, 20. In various embodiments, the endcaps 18, 20 may be formed of an electrically conductive material (e.g., copper, tin, various alloys, etc.), and the fusible element 24 may be connected to the endcaps 18, 20, such as by solder. The first and second endcaps may thus facilitate electrical connection of the fuse module 10 within a circuit. Alternatively, the first and second endcaps 18 may be formed of a dielectric material (e.g., plastic), and the fusible element 24 may extend through, and protrude from, the first and second endcaps 18, 20 (as shown in
The fusible element 24 may be any type of fusible element suitable for a desired application, including, but not limited to, a wire, a strip, a wire wound about an insulating core, etc. In various embodiments, a central portion of the fusible element 24, hereinafter referred to as “the bridge portion 25,” may be thinned, narrowed, perforated, or otherwise weakened relative to other portions of the fusible element 24 to ensure that the fusible element 24 separates at the bridge portion 25 when the fuse rating is exceeded. The present disclosure is not limited in this regard.
The interior of the fuse body 14 may be partially or entirely filled with an arc-quenching material or “fuse filler” 26 that may surround the fusible element 24. The arc-quenching material 26 may be provided for mitigating electrical arcing across separated portions of the fusible elements 24 after the fusible element 24 separates (e.g., upon the occurrence of an overcurrent condition in the fuse 12) and may thereby further enhance the breaking capacity of the fuse 12. The arc-quenching material 26 may additionally provide the fusible element 24 with mechanical support as further described below. Arc-quenching materials that be used in the fuse 12 include, but are not limited to, sand, silica, etc.
The PI 13 may include a housing 30 formed of an electrically insulating material, such as plastic, polymer, ceramic, etc. The housing 30 may have a top portion 32 that houses an interrupter assembly 34 and a bottom portion 36 that is clamped onto the fuse body 14 of the fuse 12. For example, as best shown in
The interrupter assembly 34 may include a movable piston 42 disposed within a vertically extending, hollow shaft 44 located above the fuse body 14. The interrupter assembly 34 may further include a pyrotechnic ignitor 46 disposed within the shaft 44 above the piston 42, and a drive pin 48 extending from a bottom of the piston 42. The drive pin 48 may extend into the fuse body 14 via a through hole 49 and may terminate in a cutter 50 located directly above the fusible element 24. The drive pin 48 may be formed or steel or other similarly rigid, durable material. In various embodiments, the cutter 50 may be formed of ceramic or other similarly rigid, durable, dielectric material with low arc tracking. Alternatively, the cutter 50 may be formed of an electrically 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
The pyrotechnic ignitor 46 may be coupled to a controller 52 (e.g., an airbag control unit, battery management system, etc. of an automobile). Upon the occurrence of a predefined event, such as an automobile collision (i.e., if the fuse module 10 is implemented in an automobile), the controller 52 may send an initiation signal to the pyrotechnic ignitor 46, causing the pyrotechnic ignitor 46 to be detonated. A resultant increase in pressure within the shaft 44 above the piston 42 rapidly forces the piston 42 and the drive pin 48 downwardly through the shaft 44, causing the cutter 50 to sever the fusible element 24 as shown in
Advantageously, the arc-quenching material 26 (e.g., sand) surrounding the fusible element 24 may provide the fusible element 24 with mechanical support and may hold the fusible element 24 securely in place when it is engaged by the cutter 50. This may facilitate a clean and complete cut through the fusible element 24, whereas if the fusible element 24 were merely surrounded by air the fusible element 24 would be prone to being pushed aside, partially cut, or merely bent by the cutter 50. This obviates the need for special structural features extending from the fuse body 14 for supporting the fusible element 24 as sometimes found in traditional pyrofuse modules.
In view of the above description, it will be appreciated that the fuse module of the present disclosure facilitates both “active” triggering (i.e., via the controller 52 sending an initiation signal to the pyrotechnic ignitor 46 upon the occurrence of a collision, etc.) as well as “passive” triggering (i.e., via the fusible element 24 melting/separating when subjected to currents exceeding the current rating of the fuse 12). This provides numerous advantages. For example, owing to the arc-quenching material 26 surrounding the fusible element 24, the fuse module 10 can passively interrupt very high currents (e.g., greater than 20 kA) without being destroyed or causing an electric arc of 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, even if the current in the fuse module 10 is zero, the pyrotechnic ignitor 46 can be actuated to disconnect an automobile battery from an automobile's electrical system if, for example, the vehicle experiences a collision while parked. Additionally, when operating at medium to high currents where the fuse 12 may passively clear a circuit too slowly, the pyrotechnic ignitor 46 can be actuated to clear the circuit much faster. Still further, even after the fusible element 24 is melted/separated upon the occurrence of an overcurrent condition (i.e., after passive triggering of the fuse module 10), the pyrotechnic ignitor 46 can be actuated to improve/ensure complete separation and galvanic isolation in the fusible element 24, thereby increasing open state resistance and reducing or eliminating leakage current.
While the fuse module 10 has been shown and described above as having a cutter 50 that is configured to cut directly through a bridge portion 25 of the fusible element 24, alternative embodiments of the fuse module 10 are contemplated in which the cutter 50 is adapted to indirectly separate the fusible element 24 at multiple bridge portions. For example, referring to
Referring to
Referring to
The fuse module 100 may include a multilevel cutter 150 having a through hole 151 formed therein. The first fusible element 124a may extend through the through hole 151. A top edge of the through hole 151 may define a first blade 153a disposed above the first fusible element 124a, and the bottom edge of the cutter 150 may define a second blade 153b disposed above the second fusible element 124b. Thus, when the pyrotechnic ignitor 146 is actuated, the cutter 150 may simultaneously cut and separate the first fusible element 124a and the second fusible element 124b. While not shown in
Referring to
As used herein, an element or step recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural elements or steps, unless such exclusion is explicitly recited. Furthermore, references to “one embodiment” of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features.
While the present disclosure makes reference to certain embodiments, numerous modifications, alterations and changes to the described embodiments are possible without departing from the sphere and scope of the present disclosure, as defined in the appended claim(s). Accordingly, it is intended that the present disclosure not be limited to the described embodiments, but that it has the full scope defined by the language of the following claims, and equivalents thereof.
This application claims the benefit of U.S. Provisional Patent Application No. 63/389,154, filed Jul. 14, 2022, which is incorporated by reference herein in its entirety.
Number | Date | Country | |
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63389154 | Jul 2022 | US |