Fuse with recessed end cap

Abstract

A fuse includes: a tubular fuse body; a fusible element extending through the fuse body; a first end cap disposed on a first longitudinal end of the fuse body in electrical communication with the fusible element, the first end cap having a first recess defining a first recessed surface extending into the fuse body; and a second end cap disposed on a second longitudinal end of the fuse body in electrical communication with the fusible element, the second end cap having a second recess defining a second recessed surface extending into the fuse body.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to the field of circuit protection devices, and more particularly to a surface mount fuse having an end cap adapted to improve the solder connection between the end cap and the fusible element of the fuse. BACKGROUND

[0002] Fuses are commonly used as overcurrent protection devices and are typically installed between a power source and a component in an electrical circuit to be protected. A cross-sectional view of a conventional prior art tubular fuse 10 (hereinafter "fuse 10") is shown in FIG. 1. The fuse 10 includes a hollow, electrically insulating fuse body 12 and a fusible element 14 extending diagonally through the interior of the fuse body 12 and curving or surrounding around the longitudinal end faces of the fuse body 12. Electrically conductive first and second end caps 16, 18 cover opposite longitudinal ends of the fuse body 12 and are engaged with the fusible element 14, with a quantity of solder ("solder domes") 20, 22 being disposed on the interior surfaces of the first and second end caps to provide an electrical connection with the fusible element 14. Upon the occurrence of a fault condition, such as an overcurrent condition in which the current flowing through the fusible element 14 exceeds a predefined threshold, the fusible element 14 melts or otherwise separates to interrupt the flow of current through the fuse 10, thereby protecting the connected electrical component.

[0003] A drawback associated with conventional tubular fuses of the type described above is that the electrical connection between the first and second end caps 16, 18 and the fusible element 14 can be unreliable. For example, if the solder domes 20, 22 are not properly formed (e.g., if the amount of solder used is insufficient and / or if the solder domes are malformed), the electrical contact between the first and second end caps 16, 18 and the fusible element 14 can not be robust enough to support the rated current of the fuse 10.

[0004] The present improvements can be useful for these and other considerations. SUMMARY

[0005] This Summary is provided to introduce a selection of concepts in a simplified form 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 it intended to be used to determine the scope of the claimed subject matter.

[0006] A fuse according to an embodiment of the present disclosure can include: a tubular fuse body; a fusible element extending through the fuse body; a first end cap disposed on a first longitudinal end of the fuse body in electrical communication with the fusible element, the first end cap having a first indentation defining a first indented surface extending into the fuse body; and a second end cap disposed on a second longitudinal end of the fuse body in electrical communication with the fusible element, the second end cap having a second indentation defining a second indented surface extending into the fuse body.

[0007] A fuse according to another embodiment of the present disclosure can include: a tubular fuse body having first and second end faces at opposite first and second longitudinal ends thereof; a fusible element extending through the fuse body, the fusible element having a first end bent over the first end face and a second end bent over the second end face; a first end cap disposed on the first longitudinal end of the fuse body in electrical communication with the fusible element, the first end cap defining a first indented surface extending into the fuse body; and a second end cap disposed on the second longitudinal end of the fuse body, the second end cap defining a second indented surface extending into the fuse body.

[0008] A fuse according to another embodiment of the present disclosure can include: a tubular fuse body; a first end cap disposed on a first longitudinal end of the fuse body; a second end cap disposed on a second longitudinal end of the fuse body; a fusible element extending axially through the fuse body, the fusible element being fixed to an inner surface of the first end cap at a first end and fixed to an inner surface of the second end cap at the first end, wherein the first end cap has a first indentation defining a first indented surface extending into the fuse body, the first indented surface having an annular shape and radially surrounding the first end of the fusible element, and wherein the second end cap has a second indentation defining a second indented surface extending into the fuse body, the second indented surface having an annular shape and radially surrounding the second end of the fusible element. BRIEF DESCRIPTION OF DRAWINGS

[0009] FIG. 1 is a cross-sectional view illustrating a fuse according to the prior art;

[0010] Figure 2 is a cross-sectional view illustrating a fuse according to an embodiment of the present disclosure;

[0011] Figure 3 is a cross-sectional view illustrating an end portion of a fuse according to another embodiment of the present disclosure;

[0012] Figure 4 is a cross-sectional view illustrating an end portion of a fuse according to another embodiment of the present disclosure;

[0013] Figure 5AThis is a cross-sectional view showing the end of a fuse according to another embodiment of the present disclosure;

[0014] Figure 5B It is shown Figure 5A The bottom view of the end cap of the fuse shown. Detailed Implementation

[0015] Embodiments of the fuse and its manufacturing method according to the present disclosure will now be described more fully with reference to the accompanying drawings, in which preferred embodiments of the disclosure are presented. However, the fuse and the appended method of the present disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that the disclosure will be thorough and complete, and will fully convey to those skilled in the art the scope of the fuse and the appended method. In the drawings, unless otherwise stated, the same numerals refer to the same elements throughout.

[0016] refer to Figure 2 This illustration shows a cross-sectional view of a fuse 100 (hereinafter referred to as "fuse 100") according to an exemplary embodiment of the present disclosure. For convenience and clarity, terms such as "top," "bottom," "above," "below," "lateral," "longitudinal," and "radial" may be used herein to describe the relative placement and orientation of the various components of the fuse 100, each term relating to... Figure 2 The geometry and orientation of the fuse 100 appearing in the document. The terminology will include specifically mentioned words, their derivatives, and words with similar meanings.

[0017] The fuse 100 may include an elongated tubular fuse body formed of an electrically insulating and preferably heat-resistant material (including but not limited to ceramic or glass). The fuse body 112 may have a square tube shape, but this is not critical. Alternative embodiments of the fuse 100 may have a fuse body 112 with a circular tube, an elliptical tube, a triangular tube, or the like.

[0018] Fuse 100 may include a fusible element 126, which extends from one side of fuse body 112 (e.g., as shown in the image). Figure 2 The left side of the fuse body 112 (oriented in the middle) extends diagonally through the hollow interior of the fuse body 112 to the opposite side of the fuse body 112 (e.g., as shown in the image). Figure 2The first end 128 and the second end 130 of the fusible element 126 can be bent or wrapped over the first end face 122 and the second end face 124 of the fuse body 112 onto an outer surface 131 of the fuse body 112. The fusible element 126 can be formed of an electrically conductive material, including but not limited to tin or copper, and can be configured to melt and separate upon a predetermined fault condition occurring in the fuse 100, such as an overcurrent condition in which an amount of current exceeding a predefined maximum current flows through the fusible element 126. The fusible element 126 can be any type of fusible element suitable for the desired application, including but not limited to a fuse link, a ribbon, a fuse wire wound on an insulating core, or the like.

[0019] The fuse 100 can also include electrically conductive first and second end caps 134 and 136 disposed on the first and second longitudinal ends of the fuse body 112, respectively, in electrical communication with the fusible element 126. The first and second end caps 134 and 136 can include respective first and second end walls 138 and 140 disposed in flat abutment with and parallel orientation to the first and second end faces 122 and 124 of the fuse body 112, respectively. The first and second end caps 134 and 136 can also include respective first and second side walls 142 and 144 extending perpendicularly from the first and second end walls 138 and 140, respectively, and laterally surrounding the first and second ends of the fuse body 112, respectively. The first end 128 of the fusible element 126 can be sandwiched between the first end cap 134 and the fuse body 112, and the second end 130 of the fusible element 126 can be sandwiched between the second end cap 136 and the fuse body 112. The first and second end caps 134 and 136 can be formed of an electrically conductive material, including but not limited to copper or one of its alloys, and can be plated with a nickel or other electrically conductive, corrosion-resistant coating. The first and second end caps 134 and 136 can thus facilitate electrical connection of the fuse 100 within a circuit. For example, the first and second end caps 134 and 136 can be soldered to respective terminals on a printed circuit board (not shown).

[0020] Still referring to Figure 2solder fillet 150 and second solder fillet 152 can be provided on the inner surfaces of the first end wall 138 of the first end cap 134 and the second end wall 140 of the second end cap 136, respectively, to provide a secure, robust electrical connection between the first and second end caps 134, 136 and the fusible element 126. The first end wall 138 of the first end cap 134 and the second end wall 140 of the second end cap 136 can include respective first and second recesses 154, 156 formed therein that provide the first and second end caps 134, 136 with respective first and second embossed or domed inner surfaces 158, 160 (hereinafter referred to as “first and second recessed surfaces 158, 160”) that extend to the longitudinal ends of the hollow interior of the fuse body 112. The first and second recessed surfaces 158, 160 cause the first and second solder fillets 150, 152 to pool or collect between the first and second recessed surfaces 158, 160 and the inner surface 162 of the fuse body 112, thereby concentrating a majority of the first and second solder fillets 150, 152 in the areas through which the first and second ends 128, 130 of the fusible element 126 pass. This increases the volume of solder connecting the first and second end caps 134, 136 to the fusible element 126 relative to conventional fuses in which a majority of the solder is concentrated in the center of the end cap, away from the fusible element (see, e.g., FIG. 1), thereby providing a more robust electrical connection between the first and second end caps 134, 136 and the fusible element 126 relative to conventional fuses.

[0021] As Figure 2 depicted, the first and second recessed surfaces 158, 160 are generally V-shaped. This is not intended to be limiting, and various alternative embodiments of the fuse 100 are contemplated in which the first and second recessed surfaces 158, 160 can be provided with different shapes. For example, with reference to Figure 3 , a cross-sectional view of an end of another fuse 200 is shown in accordance with embodiments of the present disclosure in which the end cap 234 of the fuse 200 has recessed surfaces 260 that have an arcuate or semi-circular shape. In Figure 4 , another example is provided showing a cross-sectional view of an end of a fuse 300 in accordance with embodiments of the present disclosure in which the end cap 334 of the fuse 300 has recessed surfaces 360 that have a plateau or flat embossed shape. In Figure 5AIn another example shown, a cross-sectional view is provided showing an end of a fuse 400 according to an embodiment of the present disclosure, where the fuse 400 has a fusible element 426 formed of a fuse wire 470 that is wrapped around an insulating core 472 and is secured to a center of an end cap 434, the insulating core 472 extending axially through the fuse body 412 (i.e., extending in a direction parallel to a longitudinal axis of the fuse body 412). In this embodiment, the end cap 434 has a recessed surface 460 having an annular shape radially surrounding the fusible element 426 (see also Figure 5B A bottom view of the end cap 434 is shown, showing the annular recess 456 corresponding to the annular recessed surface 458), which facilitates the accumulation of solder around the centrally located fusible element 426 (i.e., in the groove formed between the fusible element 426 and the recessed surface 460). Figure 5A A bottom view of the end cap 434 is shown, showing the annular recess 456 corresponding to the annular recessed surface 458), which facilitates the accumulation of solder around the centrally located fusible element 426 (i.e., in the groove formed between the fusible element 426 and the recessed surface 460).

[0022] As used herein, an element or step recited in the singular and preceded with "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 those features.

[0023] While the present disclosure has referred 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 by the one or more appended claims. Accordingly, the present disclosure is not restricted to the described embodiments, but rather has the entire scope defined by the language of the following claims and their equivalents.

Claims

1. A fuse, the fuse comprising: a tubular fuse body; a fusible element extending through the fuse body; a first end cap disposed on a first longitudinal end of the fuse body in electrical communication with the fusible element, the first end cap having a first recess defining a first recessed surface extending into the fuse body; and a second end cap disposed on a second longitudinal end of the fuse body in electrical communication with the fusible element, the second end cap having a second recess defining a second recessed surface extending into the fuse body. the fusible element extends through the fuse body in a diagonal manner, wherein a first end of the fusible element is bent over a first end face of the fuse body, and wherein a second end of the fusible element is bent over a second end face of the fuse body.

2. The fuse of claim 1, wherein, 3. The fuse of claim 1, further comprising: a first solder fillet disposed between the first recessed surface and an inner surface of the fuse body, the first solder fillet facilitating an electrical connection between the first end cap and the fusible element; and a second solder fillet disposed between the second recessed surface and an inner surface of the fuse body, the second solder fillet facilitating an electrical connection between the second end cap and the fusible element.

4. The fuse of claim 1, wherein: the first end cap comprises: a first end wall disposed in flat abutment and parallel orientation with the first end face of the fuse body; and a first side wall extending perpendicularly from the first end wall and around the first longitudinal end of the fuse body; the first recess is formed in the first end wall; and the second end cap comprises: a second end wall disposed in flat abutment and parallel orientation with the second end face of the fuse body; and a second side wall extending perpendicularly from the second end wall and around the second longitudinal end of the fuse body; the second recess is formed in the second end wall. at least one of the first recessed surface and the second recessed surface is V-shaped. at least one of the first recessed surface and the second recessed surface is semi-circular.

5. The fuse of claim 1, wherein, at least one of the first recessed surface and the second recessed surface has a plateau shape.

6. The fuse of claim 1, wherein, the fusible element extends axially through the fuse body and has a first end connected to an inner surface of the first end cap and a second end connected to an inner surface of the second end cap, wherein the first recessed surface is annular and radially surrounds the first end of the fusible element, and wherein the second recessed surface is annular and radially surrounds the second end of the fusible element.

7. The fuse of claim 1, wherein, the fusible element comprises a fuse wire wound around an electrically insulating core.

8. The fuse of claim 1, wherein, 10. A fuse, the fuse comprising:

9. The fuse of claim 1, wherein, a tubular fuse body having a first end face and a second end face at its opposite first longitudinal end and second longitudinal end; a fusible element extending through the fuse body; ​ a fusible element extending through the fuse body, the fusible element having a first end bent over the first end face and a second end bent over the second end face; a first end cap disposed on a first longitudinal end of the fuse body in electrical communication with the fusible element, the first end cap defining a first recessed surface extending into the fuse body; and a second end cap disposed on a second longitudinal end of the fuse body, the second end cap defining a second recessed surface extending into the fuse body.

11. The fuse of claim 10, wherein, The fusible element extends through the fuse body in a diagonal manner.

12. The fuse of claim 10, further comprising: a first solder fillet disposed between the first recessed surface and an inner surface of the fuse body, the first solder fillet facilitating an electrical connection between the first end cap and the fusible element; and a second solder fillet disposed between the second recessed surface and an inner surface of the fuse body, the second solder fillet facilitating an electrical connection between the second end cap and the fusible element.

13. The fuse of claim 10, wherein: the first end cap comprises: a first end wall disposed in flat abutment and parallel orientation with the first end face of the fuse body; and a first side wall extending perpendicularly from the first end wall and around the first longitudinal end of the fuse body; the first recess is formed in the first end wall; and the second end cap comprises: a second end wall disposed in flat abutment and parallel orientation with the second end face of the fuse body; and a second side wall extending perpendicularly from the second end wall and around the second longitudinal end of the fuse body; the second recess is formed in the second end wall.

14. The fuse of claim 10, wherein, At least one of the first recessed surface and the second recessed surface is V-shaped.

15. The fuse of claim 10, wherein, At least one of the first recessed surface and the second recessed surface is semi-circular.

16. The fuse of claim 10, wherein, At least one of the first recessed surface and the second recessed surface has a plateau shape.

17. A fuse, comprising: a tubular fuse body; a first end cap disposed on a first longitudinal end of the fuse body; a second end cap disposed on a second longitudinal end of the fuse body; a fusible element extending axially through the fuse body, the fusible element being fixed to an inner surface of the first end cap at a first end and to an inner surface of the second end cap at a first end; wherein the first end cap has a first recess defining a first recessed surface extending into the fuse body, the first recessed surface having an annular shape and radially surrounding the first end of the fusible element; and the second end cap has a second recess defining a second recessed surface extending into the fuse body, the second recessed surface having an annular shape and radially surrounding the first end of the fusible element. wherein the second end cap has a second recess defining a second recessed surface extending into the fuse body, the second recessed surface having an annular shape and radially surrounding the second end of the fusible element.

18. The fuse of claim 17, further comprising: a first solder fillet disposed between the first recessed surface and the fusible element; and a second solder fillet disposed between the second recessed surface and the fusible element.

19. The fuse of claim 17, wherein: the first end cap comprises: a first end wall disposed in flat abutment and parallel orientation with a first end face of the fuse body; and a first side wall extending perpendicularly from the first end wall and surrounding a first longitudinal end of the fuse body; the first recess is formed in the first end wall; and the second end cap comprises: a second end wall disposed in flat abutment and parallel orientation with a second end face of the fuse body; and a second side wall extending perpendicularly from the second end wall and surrounding a second longitudinal end of the fuse body; the second recess is formed in the second end wall. the fusible element comprises a fuse wire wound around an electrically insulating core.

20. The fuse of claim 17, wherein, ​

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