Patent Description:
Fuses are commonly implemented in automobile electrical systems for providing overcurrent protection. Most automobile 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, 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 initiator within the PI to be detonated. A resultant increase in pressure within the PI rapidly forcibly drives a projectile through a conductor that extends through the PI. Electrical current flowing through the PI is thereby interrupted, and the projectile, 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 automobile 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 and that is well suited for high voltage applications.

The abstract of <CIT> states: 'The present invention relates to a cut-off device (<NUM>) intended to be connected to an electrical circuit comprising at least one pyrotechnic initiator (<NUM>) and a body (<NUM>) in which are present: - a pressurizing chamber (<NUM>) in communication with an output (S) of said pyrotechnic initiator (<NUM>), - at least one electrically conductive portion (<NUM>) intended to be connected to the electrical circuit, - at least one fuse element (<NUM>) connected in series to the portion conductive, the initiator being connected to the terminals of said fuse element and said fuse element being configured to trip when the intensity of the current flowing through it exceeds a predetermined value and thus to actuate the initiator, and - a movable cut-off element ( <NUM>), the pyrotechnic initiator being configured to cause the breaking device to pass from a first current flow configuration to a second current cutoff configuration, the movable cutoff element being placed in m or when switching from the first to the second configuration in order to disconnect said conductive portion.

<CIT> relates to an electrical fuse, in particular for use in motor vehicles, with at least two connections and a destructible conductor provided between the connections.

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.

The present invention of the active/passive automotive fuse module is defined in the appended claims.

An active/passive automotive 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 automotive fuse module are presented. It will be understood, however, that the active/passive automotive 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 automotive fuse module to those skilled in the art.

Referring to <FIG>, a perspective view and cross-sectional views illustrating a Active/Passive automotive fuse module <NUM> (hereinafter "the fuse module <NUM>") in accordance with the present disclosure is shown. For the sake of convenience and clarity, terms such as "front," "rear," "top," "bottom," "up," "down," "vertical," and "horizontal" may be used herein to describe the relative placement and orientation of various components of the fuse module <NUM>, each with respect to the geometry and orientation of the fuse module <NUM> as it appears in <FIG><NUM>. Said terminology will include the words specifically mentioned, derivatives thereof, and words of similar import.

The fuse module <NUM> may generally include a base <NUM>, a fuse plate <NUM>, a spacing cap <NUM>, and a pyrotechnic interrupter (PI) <NUM>. The base <NUM> may be a substantially rectangular member formed of an electrically insulating material (e.g., plastic, polymer, ceramic, etc.). As illustrated in the cross-sectional view of the fuse module <NUM> shown in <FIG>, the base <NUM> may include vertically-elongated first and second fuse cavities 18a, 18b formed in the top surface thereof. The first and second fuse cavities 18a, 18b may be substantially identical and may have lower termini (e.g., floors) located above the bottom surface of the base <NUM>. The base <NUM> may further include a projectile cavity <NUM> formed in the top surface thereof, horizontally intermediate the fuse cavities 18a, 18b. The projectile cavity <NUM> may be shorter than the fuse cavities 18a, 18b. The present disclosure is not limited in this regard.

The fuse plate <NUM> may be formed from a single piece of conductive material (e.g., stamped from a single sheet of copper) and may include a bus bar portion <NUM>, first and second fusible portions 24a, 24b, and first and second terminal portions 26a, 26b. The bus bar portion <NUM> may be disposed on the top surface of the base <NUM> in a horizontal orientation and may extend from a first end disposed above the first fuse cavity 18a, over the projectile cavity <NUM>, to a second end disposed above the second fuse cavity 18b. The first and second fusible portions 24a, 24b may extend perpendicularly downwardly from the first and second ends of the bus bar portion <NUM>, respectively, into the respective first and second fuse cavities 18a, 18b. Lower ends of the first and second fusible portions 24a, 24b may extend through respective slots formed in the floors of the first and second fuse cavities 18a, 18b and may be terminate below the bottom surface of the base <NUM>. The first and second terminal portions 26a, 26b may extend perpendicularly outwardly (i.e., away from the projectile cavity <NUM>) from the lower termini of the first and second fusible portions 24a, 24b, respectively, and may include respective mounting apertures 30a, 30b formed therethrough for connecting the fuse module <NUM> within a circuit (e.g., between a battery and one or more electrical loads in an automobile).

The first and second fusible portions 24a, 24b may be configured to melt, disintegrate, or otherwise open if current flowing through the fuse plate <NUM> exceeds a predetermined threshold, or "current rating," of the fuse module <NUM>. In various examples, the first and second fusible portions 24a, 24b may include perforations, slots, thinned or narrowed segments, and/or various other features for making the first and second fusible portions 24a, 24b more susceptible to melting or opening than other portions of the fuse plate <NUM>. In a non-limiting example, the first and second fusible portions 24a, 24b may be configured to have a current rating in a range between <NUM> amps and <NUM> amps. In various embodiments, an arc-quenching, fuse filler material, such as sand, silica, or the like (not shown), may partially or entirely fill the first and second fuse cavities 18a, 18b and may substantially surround the first and second fusible portions 24a, 24b for quenching electrical arcs that could otherwise propagate upon opening of the first and second fusible portions 24a, 24b during an overcurrent condition. The fuse module <NUM> may therefore be particularly well suited for high-voltage applications. While the fuse module <NUM> has been described and illustrated as having two fusible portions 24a, 24b, various alternative embodiments of the fuse module <NUM> are contemplated that may include only one fusible portion or more than two fusible portions.

The spacing cap <NUM>, which may be formed from an electrically insulting material that is the same as, or is similar to, that from which the base <NUM> is formed, may be disposed atop the base <NUM> and the bus bar portion <NUM> of the fuse plate <NUM>. The spacing cap <NUM> may define a projectile channel <NUM> that extends vertically therethrough. The projectile channel <NUM> may be disposed directly above the bus bar portion <NUM> and the projectile cavity <NUM> of the base <NUM>. While the spacing cap <NUM> is depicted as being separate from the base <NUM> it is contemplated that, in various alternative embodiments, the base <NUM> and the spacing cap <NUM> may be formed as a single, contiguous body. The present disclosure is not limited in this regard.

The PI <NUM>, which may be of a commercially available variety (e.g., sold under the trade name "PYROSWITCH" by AUTOLIV), may include a housing <NUM> having a mounting flange <NUM>. The housing <NUM> may be disposed atop the spacing cap <NUM>, with mechanical fasteners 40a, 40b extending through the mounting flange <NUM>, the spacing cap <NUM>, and the base <NUM> for fastening the aforementioned components together in a vertically stacked relationship as shown. The housing <NUM> may have a vertically oriented, hollow shaft <NUM> extending therethrough, the shaft <NUM> having a first, open end located directly above the projectile channel <NUM> of the spacing cap <NUM>. The shaft 41may contain a projectile <NUM> that extends into the projectile channel <NUM> and rests atop the bus bar portion <NUM> of the fuse plate <NUM>. In various embodiments, the projectile <NUM> may have a pointed or wedge-shaped tip disposed in a confronting relationship with the bus bar portion <NUM>. The present disclosure is not limited in this regard.

The housing <NUM> may further containin a pyrotechnic initiator <NUM> disposed adjacent to, and configured to discharge an explosive output into, a second, top end of the shaft <NUM>. In various embodiments, the pyrotechnic initiator <NUM> may be operatively connected to a controller <NUM> (e.g., an airbag control unit, battery management system, etc.) located within an automobile. Upon the occurrence of a specified event, such as an automobile collision, the controller <NUM> may send an initiation signal to the PI <NUM>, causing the pyrotechnic initiator <NUM> to be detonated. The explosive output of the detonation may result in an increase in pressure within shaft <NUM> rapidly forcing the projectile <NUM> downwardly, through the bus bar portion <NUM> of the fuse plate <NUM> as shown in <FIG>. The bus bar portion <NUM> is thereby severed, and electrical current flowing through the fuse plate <NUM> is interrupted. The projectile <NUM>, which may be formed of a dielectric material, may provide an electrically insulating barrier between the separated ends of the bus bar portion <NUM> to prevent electrical arcing therebetween.

Referring to <FIG>, a perspective view illustrating another active/passive automotive fuse module <NUM> (hereinafter "the fuse module <NUM>") in accordance with the present disclosure is shown. The fuse module <NUM> may be substantially identical to the fuse module <NUM> described above, with the exception of the first and second terminal portions 26a, 26b of the fuse plate <NUM> of the fuse module <NUM> being replaced by vertically extending first and second terminal prongs 126a, 126b. The first and second terminal prongs 126a, 126b may accommodate "plug in" applications of the fuse module <NUM> in which the first and second terminal prongs 126a, 126b may be mated to complementary receptacles for connecting the fuse module <NUM> within a circuit.

Claim 1:
An active/passive automotive fuse module (<NUM>) comprising:
an electrically insulating base (<NUM>);
a fuse plate (<NUM>) comprising:
a bus bar portion (<NUM>) disposed on a top surface of the base (<NUM>) and above a projectile cavity (<NUM>) formed in the base (<NUM>);
a fusible portion (24a, 24b) electrically connected to the bus bar portion (<NUM>) and adapted to open when an amount of current flowing through the fuse plate (<NUM>) exceeds a current rating of the active/passive automotive fuse module (<NUM>); and
a pyrotechnic interrupter (PI) (<NUM>) disposed atop the base (<NUM>) and including a projectile (<NUM>) positioned above the bus bar portion (<NUM>), the PI (<NUM>) configured to drive the projectile (<NUM>) through the bus bar portion (<NUM>) upon actuation by a controller (<NUM>) upon the occurrence of a predetermined event, of a pyrotechnic initiator (<NUM>), causing the pyrotechnic initiator (<NUM>)to be detonated and forcing the projectile (<NUM>) to sever the bus bar portion (<NUM>), characterised in that the fusible portion (24a, 24b) extends perpendicularly from the bus bar portion (<NUM>).