PROTECTION DEVICE INCLUDING MULTI-PLANE FUSIBLE ELEMENT
20230162939 · 2023-05-25
Assignee
Inventors
Cpc classification
H01H85/08
ELECTRICITY
International classification
Abstract
Disclosed are various protection devices and associated methods. In some embodiments, a protection device may include a substrate and a fusible element coupled to the substrate, wherein the fusible element may include a first end opposite a second end, and wherein the first and second ends wrap around the substrate. The fusible element may further include a central section comprising a plurality of segments connected end-to-end in a continuous arrangement between the first and second ends, wherein a first set of segments of the plurality of segments extends along a first plane, and wherein a second set of segments of the plurality of segments extends along a second plane, different than the first plane.
Claims
1. A protection device, comprising: a substrate; and a fusible element coupled to the substrate, the fusible element comprising: a first end opposite a second end, wherein the first and second ends wrap around the substrate; and a central section comprising a plurality of segments connected end-to-end in a continuous arrangement between the first and second ends, wherein a first set of segments of the plurality of segments extends along a first plane, and wherein a second set of segments of the plurality of segments extends along a second plane, different than the first plane.
2. The protection device of claim 1, wherein the first plane is a first distance, along a first direction, from an upper surface of the substrate, and wherein the second plane is a second distance, along the first direction, from the upper surface of the substrate.
3. The protection device of claim 2, wherein the second set of segments of the plurality of segments overlaps the first set of segments of the plurality of segments in a second direction.
4. The protection device of claim 3, wherein the second direction is orthogonal to the first direction.
5. The protection device of claim 3, wherein an interior angle formed between the first direction and the second direction is less than 90 degrees.
6. The protection device of claim 1, further comprising a third set of segments, wherein the third set of segments extends along a third plane, and wherein the third plane is different than the first plane and the second plane.
7. The protection device of claim 1, further comprising a filler material extending over a portion of the central section of the fusible element.
8. The protection device of claim 1, further comprising a first filler material and a second filler material formed over the central section of the fusible element, wherein a target fusing location of the central section of the fusible element remains uncovered by the first filler material and the second filler material.
9. The protection device of claim 1, the plurality of segments comprising a plurality of pairs of first and second segments connected at a third segment, wherein the first and second segments extend parallel to one another.
10. The protection device of claim 1, wherein each segment of the plurality of segments includes a first main side opposite a second main side, a first segment end opposite a second segment end, and a first side opposite a second side, wherein a plane defined by the first main side is parallel to a plane defined by the second main side.
11. A fusible element of a protection device, comprising: a first end opposite a second end, wherein the first and second ends are operable to wrap around a substrate; and a central section comprising a plurality of segments connected end-to-end in a serpentine pattern between the first and second ends, wherein a first set of segments of the plurality of segments extends along a first plane, wherein a second set of segments of the plurality of segments extends along a second plane, different than the first plane.
12. The fusible element of claim 11, wherein the first plane is a first distance, along a first direction, from an upper surface of the substrate, and wherein the second plane is a second distance, along the first direction, from the upper surface of the substrate.
13. The fusible element of claim 11, wherein the second set of segments of the plurality of segments overlaps the first set of segments of the plurality of segments in a second direction.
14. The fusible element of claim 11, wherein the first plane is orthogonal to the second plane.
15. The fusible element of claim 11, wherein the first plane and the second plane are oriented at an angle with respect to one another, and wherein the angle is less than 90°.
16. The fusible element of claim 11, further comprising a third set of segments, wherein the third set of segments extends along a third plane, and wherein the third plane is different than the first plane and the second plane.
17. The fusible element of claim 11, the plurality of segments comprising a plurality of pairs of first and second segments connected at a third segment, wherein the first and second segments extend parallel to one another, and wherein the first and second segments extend perpendicular to the third segment.
18. The fusible element of claim 11, wherein each segment of the plurality of segments includes a first main side opposite a second main side, a first segment end opposite a second segment end, and a first side opposite a second side, wherein a plane defined by the first main side is parallel to a plane defined by the second main side, wherein a plane defined by the first side is parallel to a plane defined by the second side.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The accompanying drawings illustrate exemplary approaches of the disclosed embodiments so far devised for the practical application of the principles thereof, and wherein:
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[0029] The drawings are not necessarily to scale. The drawings are merely representations, not intended to portray specific parameters of the disclosure. The drawings are intended to depict exemplary embodiments of the disclosure, and therefore are not to be considered as limiting in scope. In the drawings, like numbering represents like elements.
[0030] Furthermore, certain elements in some of the figures may be omitted, or illustrated not-to-scale, for illustrative clarity. The cross-sectional views may be in the form of “slices”, or “near-sighted” cross-sectional views, omitting certain background lines otherwise visible in a “true” cross-sectional view, for illustrative clarity. Furthermore, for clarity, some reference numbers may be omitted in certain drawings.
DETAILED DESCRIPTION
[0031] Protection devices, fuse assemblies, and methods in accordance with the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, where embodiments are shown. The protection devices, fuse assemblies, and methods may be embodied in many different forms and are not to be construed as being limited to the embodiments set forth herein. Instead, these embodiments are provided so the disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
[0032] As noted above, common slow-blow fuses use a wound wire design to meet the I2t requirements of the device. However, this option has known challenges on the solder-joint reliability. While a single element-termination with a stamped element design may resolve this issue, the length of element is limited. The present disclosure caters both to the need for longer elements and robust termination.
[0033] In some embodiments, a multi-plane serpentine series element is provided as the fusible element. The fusible element may start with a metal sheet, which is formed with a serpentine/spiral or any element pattern via etching or cutting, and intentionally designed to be longer and exceed the fuse body width dimension. Once configured, the fusible element may extend along multiple planes above a substrate of the body. In some embodiments, a selective molding of silicone filler may be applied on the fuse element, sparing the element weak-spot for arc quenching purposes and keeping the element in-place and the pattern intact.
[0034] It will be appreciated that at least the following technical and functional advantages are provided by the embodiments of the present disclosure. Firstly, the folded fusible element structure maximizes the length of the fusible element that can fit on a space constrained body. Secondly, a higher resistance capability may be provided for low current. Thirdly, the longer element length allows room for higher I2t values. Fourthly, selective molding of the silicone filler enhances fuse breaking capacity while maintaining the OL performance. Fifthly, higher reliability may be provided with a robust, solderless termination. Sixthly, placement of the fusible element is easier as compared to wire, therefore simplifying assembly and increasing throughput. The following will further detail these and other advantages of the present disclosure.
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[0036] As shown, the fusible element 120 may include a first end 121 opposite a second end 122, wherein the first and second ends 121, 122 operate as electrical terminals. The first end 121 and the second end 122 may be in direct contact with the shoulders 112 and the lower surface 107 of the substrate 104. Between the first end 121 and the second end 122 is a central section 124 comprising a plurality of segments 125 connected end-to-end in a continuous arrangement. As will be described in greater detail herein, the central section 124 may be arranged in a looping or serpentine pattern, which extends along multiple planes. For example, a first set of segments 125A of the plurality of segments 125 extends along a first plane, while a second set of segments 125B of the plurality of segments 125 extends along a second plane, different than the first plane. As used herein, each segment 125 may correspond to a length or portion of the central section having a bend at one or both ends. As shown and described herein as being straight, or substantially straight, the segments 125 also be curved, sloped, or bent. Embodiments herein are not limited in this context.
[0037] In accordance with known electrical fuses, the fusible element 120 is constructed to melt, vaporize, disintegrate or otherwise structurally fail when a predetermined magnitude of electrical current flows through the fuse for a duration of time, sometimes referred to as an overcurrent condition, that may damage sensitive electronic components. That is, the current path through the fuse assembly 102 is designed to fail and open the current path through the fusible element 120 to avoid damage to sensitive circuit components. The amount of current that the fusible element 120 may sustain before opening the current path may vary depending on its particular material properties and dimensional aspects. Various fuse link or fuse element constructions are known for such a purpose. Once the fusible element 120 is opened, the fuse assembly 102 may be replaced to restore the electrical circuitry to full operation.
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[0039] In the pre-formed, or flattened, configuration, the fusible element 220 may have an overall length extending in the x-direction, an overall width extending in the z-direction, and an overall height or thickness extending in the y-direction. In some examples, the overall width of the fusible element 220, e.g., in the central section 124, may be greater than the overall width of the substrate 104 (
[0040] As further shown, the plurality of segments 225 may include a plurality of pairs 238A-238C of first segments 225-1 and second segments 225-2 each connected at a bend, or third segment 225-3. The third segment 225-3 of pair 238B may correspond to a target fusing location of the fusible element 220. In some embodiments, the first and second segments 225-1, 225-2 are separated from one another by a gap and may extend parallel to one another. Although non-limiting, pairs 238A and 238C may have a width (e.g., along the z-direction) greater than a width of pair 238B. As further shown, a gap between first and second segments 225-1, 225-2 of pair 238B may be greater/larger (e.g., in the x-direction) than a gap between first and second segments 225-1, 225-2 of pairs 238A and 238C. Embodiments herein are not limited in this context.
[0041] Turning now to
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[0045] As shown in the device 200 of
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[0051] In this embodiment, the first and second ends 621, 622 may be asymmetrical. For example, a side segment 652 extending from a base segment 653 of the first end 621 may have a different height (e.g., along the y-direction) than a height of a second side segment 654 extending from a base segment 656 of the second end 622. Said another way, an upper segment 658 of the first end 621 and an upper segment 659 of the second end 622 may extend along a different planes.
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[0054] In the bent configuration of
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[0057] In sum, embodiments of the present disclosure provide a folded fusible element, which decreases an overall fuse footprint while enabling a higher I2t value for a same low-current rating of planar stamped fusible element. It has been found that the folded fusible element herein may provide approximately 68% longer element length with the same cross-sectional area.
[0058] As used herein, an element or step recited in the singular and proceeded with the word “a” or “an” is 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 also incorporating the recited features.
[0059] The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Accordingly, the terms “including,” “comprising,” or “having” and variations thereof are open-ended expressions and can be used interchangeably herein.
[0060] The phrases “at least one”, “one or more”, and “and/or”, as used herein, are open-ended expressions and are both conjunctive and disjunctive in operation. For example, expressions “at least one of A, B and C”, “at least one of A, B, or C”, “one or more of A, B, and C”, “one or more of A, B, or C” and “A, B, and/or C” means A alone, B alone, C alone, A and B together, A and C together, B and C together, or A, B and C together.
[0061] All directional references (e.g., proximal, distal, upper, lower, upward, downward, left, right, lateral, longitudinal, front, back, top, bottom, above, below, vertical, horizontal, radial, axial, clockwise, and counterclockwise) are just used for identification purposes to aid the reader's understanding of the present disclosure. The directional references do not create limitations, particularly as to the position, orientation, or use of the disclosure. Connection references (e.g., attached, coupled, connected, and joined) are to be construed broadly and may include intermediate members between a collection of elements and relative movement between elements unless otherwise indicated. As such, connection references do not necessarily infer two elements are directly connected and in fixed relation to each other.
[0062] Furthermore, identification references (e.g., primary, secondary, first, second, third, fourth, etc.) are not intended to connote importance or priority, and are used to distinguish one feature from another. The drawings are for purposes of illustration, and the dimensions, positions, order and relative sizes reflected in the drawings attached hereto may vary.
[0063] Furthermore, the terms “substantial” or “approximately,” as well as the terms “approximate” or “approximately,” can be used interchangeably in some embodiments, and can be described using any relative measures acceptable by one of ordinary skill in the art. For example, these terms can serve as a comparison to a reference parameter, to indicate a deviation capable of providing the intended function. Although non-limiting, the deviation from the reference parameter can be, for example, in an amount of less than 1%, less than 3%, less than 5%, less than 10%, less than 15%, less than 20%, and so on.
[0064] While certain embodiments of the disclosure have been described herein, the disclosure is not limited thereto, as the disclosure is as broad in scope as the art will allow and the specification may be read likewise. Therefore, the above description is not to be construed as limiting. Instead, the above description is merely as exemplifications of particular embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.