Patent Publication Number: US-10325745-B2

Title: Multiple element fuse

Description:
FIELD OF THE DISCLOSURE 
     The disclosure relates generally to the field of protection device components and, more specifically, to multiple element fuses. 
     BACKGROUND OF THE DISCLOSURE 
     Fuses are overcurrent protection devices for electrical circuitry, and are widely used to protect electrical power systems and prevent damage to circuitry and associated components when specified circuit conditions occur. A fusible element or assembly is coupled between terminal elements of the fuse, and when specified current conditions occur, the fusible element or assembly, disintegrates, melts or otherwise structurally fails, and opens a current path between the fuse terminals. Line side circuitry may therefore be electrically isolated from load side circuitry through the fuse, preventing possible damage to load side circuitry from overcurrent conditions. 
     Fuses may be single or multiple-element, the later having performance advantages but being more complicated and costly to manufacture. This is due in part to having multiple parts, which requires complicated fixturing and increases the possibility for error. In view of these challenges, improvements in multiple element electrical fuses are desired. 
     SUMMARY 
     In one approach according to embodiments of the disclosure, a multiple element fuse comprising a first fuse element including a first pair of terminals joined by a first fusible link, and a second fuse element including a second pair of terminals joined by a second fusible link, wherein the first pair of terminals is directly physically coupled with the second pair of terminals. 
     In another approach according to embodiments of the disclosure, a method of forming a multiple element fuse includes providing a first fuse element including a first pair of terminals joined by a first fusible link, providing a second fuse element including a second pair of terminals joined by a second fusible link, and directly coupling the first pair of terminals to the second pair of terminals such that the first pair of terminals and the second pair of terminals are oriented parallel to one another along different planes. 
     In yet another approach according to embodiments of the disclosure, a multiple element fuse includes a first fuse element including a first pair of terminals joined by a first fusible link, and a second fuse element including a second pair of terminals joined by a second fusible link, wherein the first pair of terminals and second pair of terminals each include an inner surface and an outer surface, and wherein the inner surfaces of the first pair of terminals and the second pair of terminals are parallel and in directly physical contact with one another. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is perspective view of a multiple element fuse in accordance with embodiments of the present disclosure. 
         FIG. 2  is a side view of the multiple element fuse of  FIG. 1  in accordance with embodiments of the present disclosure. 
         FIG. 3  is a perspective view of a multiple element fuse at an initial processing stage in accordance with embodiments of the present disclosure. 
         FIG. 4  is a perspective view of the multiple element fuse of  FIG. 3  following a further processing step in accordance with embodiments of the present disclosure. 
         FIG. 5  is a perspective view of the multiple element fuse of  FIG. 3  following a further processing step in accordance with embodiments of the present disclosure. 
         FIG. 6  is perspective view of a  5 -fuse element array in accordance with embodiments of the present disclosure. 
         FIG. 7  is an exploded side view of the multiple element fuse of  FIG. 6  in accordance with embodiments of the present disclosure. 
         FIG. 8  is top view of a multiple element fuse in accordance with embodiments of the present disclosure. 
         FIG. 9  is side view of the multiple element fuse of  FIG. 8  following formation in accordance with embodiments of the present disclosure. 
         FIG. 10  is side view of the multiple element fuse of  FIG. 8  following formation in accordance with embodiments of the present disclosure. 
         FIG. 11  is top view of a multiple element fuse in accordance with embodiments of the present disclosure. 
         FIG. 12  is side view of the multiple element fuse of  FIG. 11  following formation in accordance with embodiments of the present disclosure. 
     
    
    
     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 be considered as limiting in scope. In the drawings, like numbering represents like elements. 
     DETAILED DESCRIPTION 
     Various approaches in accordance with the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, where embodiments of a device and method are shown. The device(s) and method(s) may be embodied in many different forms and are not be construed as being limited to the embodiments set forth herein. Instead, these embodiments are provided so this disclosure will be thorough and complete, and will fully convey the scope of the system and method to those skilled in the art. 
     For the sake of convenience and clarity, terms such as “top,” “bottom,” “upper,” “lower,” “vertical,” “horizontal,” “lateral,” and “longitudinal” will be used herein to describe the relative placement and orientation of these components and their constituent parts, with respect to the geometry and orientation of a component of a semiconductor manufacturing device as appearing in the figures. The terminology will include the words specifically mentioned, derivatives thereof, and words of similar import. 
     As used herein, an element or operation recited in the singular and proceeded with the word “a” or “an” are understood as potentially including plural elements or operations as well. Furthermore, references to “one embodiment” of the present disclosure are not intended to be interpreted as precluding the existence of additional embodiments also incorporating the recited features. 
     Furthermore, in the following description and/or claims, the terms “on,” “overlying,” “disposed on” and “over” may be used in the following description and claims. “On,” “overlying,” “disposed on” and “over” may be used to indicate that two or more elements are in direct physical contact with each other. However, “on,”, “overlying,” “disposed on,” and over, may also mean that two or more elements are not in direct contact with each other. For example, “over” may mean that one element is above another element but not contact each other and may have another element or elements in between the two elements. Furthermore, the term “and/or” may mean “and”, it may mean “or”, it may mean “exclusive-or”, it may mean “one”, it may mean “some, but not all”, it may mean “neither”, and/or it may mean “both”, although the scope of claimed subject matter is not limited in this respect. 
     As will be described in detail herein, embodiments of the present disclosure include multiple element fuses having a first fuse element including a first pair of terminals joined by a first fusible link, and a second fuse element including a second pair of terminals joined by a second fusible link. The first pair of terminals may be directly physically coupled with the second pair of terminals. In some embodiments, the first pair of terminals and the second pair of terminals are stacked relative to one another and joined by one or more linking elements, thus causing the first fusible link and the second fusible link to extend parallel to one another. In some embodiments, a first plurality of terminal pairs are integrally linked adjacent one another along a same plane, and then subsequently coupled to a second plurality of terminal pairs. 
     As described above, multiple-element fuses have performance advantages over single element fuses. To overcome deficiencies of the prior art, embodiments of the present disclosure simplify the design and manufacture of a dual element fuse into one part that is simpler to assemble and minimizes inventory. In some embodiments, the raw material used to manufacture the multiple-element fuse is first machined to the proper thickness, or starts out at the proper raw material thickness, and is then formed to the intended shape. The multiple-element fuse may then be prepared by adding a solder overlay before being formed into a final shape/structure. At least one technical benefit of this design process is that the fuse solder operation occurring before forming the multiple-element fuse into its final shape is simplified, and that multiple fuse elements are formed at the same time, thus eliminating length variation between each individual fuse elements. Having the terminal and element section as one part also advantageously minimizes handling of the fragile, formed element section. Although not limited to any particular implementation, many higher amperage hybrid electrical vehicles (HEV) may benefit from the multiple-element fuse of the present disclosure. 
     Referring now to  FIGS. 1-2 , a multiple-element fuse  100  (hereinafter “fuse”) according to some embodiments of the present disclosure will be described in greater detail. As shown, the fuse  100  includes a first fuse element  102  including a first pair of terminals  104 A-B joined by a first fusible link  108 , and a second fuse element  110  including a second pair of terminals  112 A-B joined by a second fusible link  116 . As shown, the first pair of terminals  104 A-B are directly physically coupled with the second pair of terminals  112 A-B, and joined together by one or more linking elements  118 , which are integrally formed with the first and second pairs of terminals  104 A-B and  112 A-B. In some embodiments, the first and second fuse elements  102 ,  110  may be copper or a copper alloy exhibiting good conductivity and malleability. 
     The first and second pairs of terminals  104 A-B and  112 A-B may include terminal bodies  120 A-B each having an opening  122  formed therein. The terminal bodies  120 A-B are generally flat and include respective inner surfaces  124 A-D and outer surfaces  128 A-D, wherein the inner surfaces  124 A-B of the first pair of terminals  104 A-B and the inner surfaces  124 C-D of the second pair of terminals  112 A-B are in parallel abutment and/or in direct physical contact with one another. As shown, the terminal bodies  120 A-D further including adjacent edges connecting inner surfaces  124 A-D and outer surfaces  128 A-D, wherein the linking element  118  is integrally formed with the edges. It will be appreciated that the terminal bodies  120 A-D are not limited to any particular type or shape. For example, various types of terminal sections may include blade-shaped terminal sections and box-shaped terminal sections (insertion types of terminal sections) structured to cover a connection terminal. 
     In some embodiments, the first fusible link  108  and the second fusible link  116  extend parallel, or substantially parallel, to one another. Each of the fusible links  108 ,  116  may include a plurality of solid sections  130  joined together by electrically conductive bridges  132 , which may be a result of multiple openings  134  being formed through the first and second fusible links  108 ,  116 . In various embodiments, the first and second fusible links  108 ,  116  may have a same or reduced thickness as compared to respective terminals  104 A-B and  112 A-B. As shown, each fusible link  108 ,  116  further includes respective shoulder regions  138  and  140  connected to terminals  104 A-B and  112 A-B. In various embodiments, the shoulder regions  138  may have a bent or curved shape, thus causing the first pair of terminals  104 A-B and the first fusible link  108  to extend parallel to one another along different x-y planes. Similarly, the shoulder regions  140  cause the second pair of terminals  112 A-B and the second fusible link  116  to extend parallel to one another along different x-y planes. It will be appreciated that the fusible links  108  and  116  of the present embodiment are not limited to any specific shape or type. For example, each fusible link  108 ,  116  may have a portion having a smaller cross-section, and/or an area having a lower melting point, such as tin, silver, lead, nickel, or an alloy thereof. 
     Turning now to  FIGS. 3-5 , a method for forming the fuse  100  according to embodiments of the disclosure will be described in greater detail. As shown in  FIG. 3 , the method may include providing the first fuse element  102  including the first pair of terminals  104 A-B joined by the first fusible link  108 , and providing the second fuse element  110  including the second pair of terminals  112 A-B joined by the second fusible link  116 . In some embodiments, the first fuse element  102  and the second fuse element  110  are initially arranged adjacent one another, along a same plane, after being machined/manufactured from a single piece of material. The first and second fuse elements  102 ,  110  may be coupled together by just the linking elements  118 , which may extend between interior edges of each of the first and second pairs of terminals  104 A-B,  112 A-B. 
     Next, as shown in  FIG. 4 , the shape of the first and second fuse elements  102 ,  110  may be modified by bending shoulder regions  138  and  140  connected to respective terminals  104 A-B and  112 A-B. In some embodiments, the shape of the first and second fuse elements  102 ,  110  depends on, for example, an application of the fuse  100 , a fuse element type, and a desired rated current. To obtain material formed into the developed shape of the fuse  100 , a stamping tool having a cutting blade conforming to this developed shape may be used. In some embodiments, the terminals and the fusible links may be individually obtained through different processes. 
     As shown, after bending shoulder regions  138  and  140 , the first and second pairs of terminals  104 A-B,  112 A-B extend adjacent one another along a first plane, while the first and second fusible links  108 ,  116  extend along a second plane. Solder holes  142  through each of the fusible links  108  and  116  may then be filled with a solder material (not shown), and the first and second fuse elements  102 ,  110  may be stacked by folding the linking elements  118 , as shown in  FIG. 5 . In exemplary embodiments, the inner surface  124 A of the first terminal  104 A is brought toward the inner surface  124 C of the second terminal  112 A, and the inner surface  124 B of the first terminal  104 B is brought towards the inner surface  124 D of the second terminal  112 B. Once the first and second fuse elements  102  and  110  are in place, for example as shown in  FIGS. 1-2 , the first pair of terminals  104 A-B are directly physically coupled to, and/or directly adjacent and in abutment with, the second pair of terminals  112 A-B. In some embodiments, the first and second pairs of terminals  104 A-B,  112 A-B are secured together, for example, by laser welding, spot welding, and/or ultrasonic welding. As shown, the first pair of terminals  104 A-B and the second pair of terminals  112 A-B are stacked and oriented parallel to one another, along different x-y planes. It will be appreciated that the length and thickness of the linking elements  118  is selected to permit the folding and stacking of the first and second fuse elements  102 ,  110 . 
     Turning now to  FIGS. 6-7 , a multiple-element fuse  200  (hereinafter “fuse”) according to some embodiments of the present disclosure will be described in greater detail. In this embodiment, the fuse  200  may be a 5-fuse element array, e.g., used for mass production. The fuse  200  allows assembly of 5 fuses at once on a fixture by removing square sections between each terminal once mounted to a fixture. One will appreciate, however, as few as two single fuse elements may be stacked atop each other to make one fuse, or may be greater than the 5 fuses per array shown in  FIG. 6 . Various other embodiments may stack 3, 4, 5, etc. fuse elements and terminals atop one another to make a multiple element fuse, wherein each may be formed differently to keep the fusing elements separated within the fuse body. 
     As shown, the fuse  200  is a dual element fuse with multiple fuses stacked atop one another. For example, the fuse  200  includes a first layer  250  attached to a second layer  255 , both of which may be copper or a copper alloy exhibiting good conductivity and bending and spreading performances. The first layer  250  may include a first plurality of pairs of terminals  201 A-B,  203 A-B,  205 A-B,  207 A-B, and  209 A-B integrally coupled together and extending along a same plane. Meanwhile, the second layer  250  may include a second plurality of pairs of terminals  211 A-B,  213 A-B,  215 A-B,  217 A-B, and  219 A-B integrally coupled together and extending along a same plane. 
     The first and second layers  250 ,  255  include a plurality of fusible links  221 - 230  extending between respective terminal pairs. In some embodiments, the fusible links  221 ,  223 ,  225 ,  227 , and  229  of the first layer  250  are parallel to one another, for example, along a length (i.e., the x-direction) of the fuse  200 . Similarly, the fusible links  222 ,  224 ,  226 , and  228  of the second layer  250  are spaced apart and parallel to one another along the length of the fuse  200 . Meanwhile, the fusible links  221  and  222 ,  223  and  224 , etc., are spaced apart and parallel to each other along the z-direction. 
     During manufacture/assembly of the fuse  200 , each of the first and second layers  250  and  255  may be provided as a separate piece of material. The terminals and fusible links of each of the first and second layers  250  and  255  may then be machined or formed. Initially, the terminals and the fusible links of the first layer  250  may be arranged along a same plane, and the terminals and the fusible links of the second layer  255  may be provided along another plane. The shape of the plurality of fusible links  221 - 230  may then be modified by bending one or more of the shoulder regions  238  and  240  of the plurality of fusible links  221 - 230 . Solder holes  242  through each of the fusible links  221 - 230  may then be filled with a solder material (not shown), and the first and second layers  250 ,  255  may be stacked. In exemplary embodiments, an inner surface  260  of the first layer  250  is secured to the inner surface  264  of the second layer  255 , for example, by laser welding, spot welding, and/or ultrasonic welding. 
     Turning now to  FIGS. 8-10 , a multiple-element fuse  300  (hereinafter “fuse”) according to some embodiments of the present disclosure will be described in greater detail. As shown, the fuse  300  includes a first fuse element  302  including a first pair of terminals  304 A-B joined by a first fusible link  308 , and a second fuse element  310  including a second pair of terminals  312 A-B joined by a second fusible link  316 . As shown, the first pair of terminals  304 A-B are directly physically coupled with the second pair of terminals  312 A-B, for example, by one or more linking elements  318 , which are integrally formed with the first and second pairs of terminals  304 A-B and  312 A-B. In other embodiments, no separate linking elements join the first pair of terminals  304 A-B with the second pair of terminals  312 A-B. The first and second pairs of terminals  304 A-B and  312 A-B may include respective terminal bodies  320 A-D each having an opening  322  formed therein. The terminal bodies  320 A-D are generally flat and include respective inner surfaces  324 A-D, wherein the inner surfaces  324 A-B of the first pair of terminals  304 A-B and the inner surfaces  324 C-D of the second pair of terminals  312 A-B may be parallel to one another once formed. As shown, the terminal bodies  320 A-D further include adjacent edges connecting inner surfaces  324 A-D via the linking elements  318 . 
     The fuse  300  may further include a third pair of terminals  370 A-B directly physically coupled with at least one of the first pair of terminals  304 A-B and the second pair of terminals  312 A-B. In the embodiment shown, the third pair of terminals  370 A-B is directly coupled to the second pair of terminals  312 A-B by a set of linking elements  335 . In other embodiments, no separate linking element(s) joins the third pair of terminals  370 A-B with the first pair of terminals  304 A-B and/or the second pair of terminals  312 A-B. In some embodiments, the third pair of terminals  370 A-B may not be joined together by a fusible link. Instead, during assembly, the third pair of terminals  370 A-B may be folded about the linking elements  335  and sandwiched between the first pair of terminals  304 A-B and the second pair of terminals  312 A-B, for example as demonstrated in  FIG. 9 . In yet other embodiments, the third pair of terminals  370 A-B may be in direct contact with an outer surface of either the first pair of terminals  304 A-B or the second pair of terminals  312 A-B, as demonstrated in  FIG. 10 . It will be appreciated that additional terminal layers may be provided to further increase the thickness and strength of this portion of the fuse  300 . For example, as many as four or more terminal layers may be stacked atop one another (e.g., in the z-direction) in other embodiments. Furthermore, it&#39;ll be appreciated that the third pair of terminals  370 A-B may be devoid of any linking elements (e.g., linking elements  335 ) and, instead, may be directly coupled with at least one of the first pair of terminals  304 A-B and the second pair of terminals  312 A-B. 
     Turning now to  FIGS. 11-12 , a multiple-element fuse  400  (hereinafter “fuse”) according to some embodiments of the present disclosure will be described in greater detail. As shown in  FIG. 11 , the fuse  400  includes a first fuse element  402  including a first pair of terminals  404 A-B joined by a first fusible link  408 , and a second fuse element  410  including a second pair of terminals  412 A-B joined by a second fusible link  416 . As shown, the first pair of terminals  404 A-B are directly physically coupled with the second pair of terminals  412 A-B, for example, by one or more linking elements  418 , which are integrally formed with the first and second pairs of terminals  404 A-B and  412 A-B. The first and second pairs of terminals  404 A-B and  412 A-B may include respective terminal bodies  420 A-D each having an opening  422  formed therein. The terminal bodies  420 A-D are generally flat and include respective inner surfaces  424 A-D, wherein the inner surfaces  424 A-B of the first pair of terminals  404 A-B and the inner surfaces  424 C-D of the second pair of terminals  412 A-B may be parallel to one another once the fuse  400  is formed. As shown, the terminal bodies  420 A-D further include adjacent edges connecting inner surfaces  424 A-D via the linking elements  418 . 
     The fuse  400  may further include a third fuse element  469  including a third pair of terminals  470 A-B directly physically coupled with at least one of the first pair of terminals  404 A-B and the second pair of terminals  412 A-B. In the embodiment shown, the third pair of terminals  470 A-B are directly coupled to the second pair of terminals  412 A-B by a set of linking elements  435 . The third pair of terminals  470 A-B may be further joined together by a third fusible link  472 , which may be the same or different from the fusible links  408  and  416 . In the embodiment shown, the third pair of terminals  470 A-B may be folded about the linking elements  435 , and sandwiched between the first pair of terminals  404 A-B and the second pair of terminals  412 A-B, as demonstrated in  FIG. 12 . The third fusible link  472  may be straight, or substantially straight, extend along a same x-y plane with the third pair of terminals  470 A-B after the fuse  400  is formed. Stated another way, the shoulder regions  438  of the third fusible link  472  may not be bent like that of the first and second fusible links  408  and  416 . However, the central regions of each of the first, second, and third fusible links  408 ,  416 , and  472  may be spaced apart and parallel to one another along the z-direction when the fuse  400  is formed. It will be appreciated that additional terminal pairs/fusible links may be added to further increase thickness and strength the fuse  400 . 
     In sum, the fuses of the present disclosure allow for simple fabricating processing, advantageously enhancing the productivity of fuse elements and fuses that contain them. Furthermore, the fuses may include multiple fusible links arranged in parallel, which advantageously splits a fusing current flow into multiple flows, thus reducing arc energy. 
     While certain embodiments of the disclosure have been described herein, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but 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.