Chip fuse with floating lead

Abstract

The invention discloses a chip fuse with a floating lead. A chip fuse includes a fuse body having: an electrically insulating floating lead support layer; first and second floating leads of metal disposed atop the floating lead support layer in a spaced-apart arrangement so as to define a gap therebetween; an electrically insulating barrier layer disposed atop the first and second floating leads; an electrically insulating fuse support layer disposed atop the barrier layer; and an electrically conductive fuse layer disposed atop the fuse support layer, the fuse layer including first and second terminal portions connected by a fusible portion. The sheet fuse may also include conductive first and second end terminals disposed on opposite ends of the fuse body, where the first end terminal is electrically connected to the first terminal portion, and where the second end cap is electrically connected to the second terminal portion.

Description

Technical Field

[0001] The present disclosure relates generally to the field of circuit protection devices, and more particularly to blade fuses having embedded floating leads for heat dissipation and increased interrupting capability. Background Art

[0002] Blade fuses (also commonly referred to as "solid" fuses) typically include a fusible element sandwiched between two or more layers of dielectric material (e.g., ceramic) that form the fuse body. The fusible element extends between conductive terminals located at opposite ends of the fuse body. When the fusible element melts during an overcurrent condition, an arc may sometimes propagate between the separated portions of the fusible element. The arc may generate a large amount of heat, which in some cases may rupture the dielectric layer of the blade fuse, thereby creating a fire hazard and potentially damaging surrounding components. The likelihood of rupture is generally proportional to the severity of the overcurrent condition. The maximum current that a blade fuse can block without rupture is called the "breaking capacity" of the blade fuse. It is generally desirable to maximize the breaking capacity of a blade fuse without significantly increasing the size or form factor of the blade fuse.

[0003] It is with respect to these and other considerations that the present improvements may be useful. Summary of the invention

[0004] 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 as an aid in determining the scope of the claimed subject matter.

[0005] A blade fuse includes a fuse body, the fuse body including: an electrically insulating floating lead support layer; a metallic first floating lead and a second floating lead, the first floating lead and the second floating lead being arranged in a spaced-apart arrangement atop the floating lead support layer, thereby defining a gap therebetween; an electrically insulating barrier layer, the barrier layer being arranged atop the first floating lead and the second floating lead; an electrically insulating fuse support layer, the fuse support layer being arranged atop the barrier layer; and an electrically conductive fuse layer, the fuse layer being arranged atop the fuse support layer, the fuse layer including a first terminal portion and a second terminal portion connected by a fusible portion. The blade fuse also includes: an electrically conductive first end terminal and a second end terminal, the first end terminal and the second end terminal being arranged on opposite ends of the fuse body, wherein the first end terminal is electrically connected to the first terminal portion, and wherein the second end terminal is electrically connected to the second terminal portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] By way of example, various embodiments of the disclosed system will now be described with reference to the accompanying drawings, in which

[0007] In the figure:

[0008] Figure 1A is a perspective view showing a blade fuse according to an exemplary embodiment of the present disclosure;

[0009] Figure 1B It is shown Figure 1A An exploded view of a blade fuse is shown;

[0010] Figure 2 yes Figure 1B Non-limiting examples of alternative shapes for floating leads are shown;

[0011] Figure 3 yes Figure 1B Another non-limiting example of an alternative shape for a floating lead is shown. DETAILED DESCRIPTION

[0012] The blade fuse according to the present disclosure will now be described more fully with reference to the accompanying drawings, in which preferred embodiments of the blade fuse are presented. However, it will be understood that the blade fuse described below can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Instead, these embodiments are provided so that the present disclosure will be able to convey certain exemplary aspects of the blade fuse to those skilled in the art.

[0013] refer to Figure 1A and Figure 1B , shows a perspective view and an exploded view illustrating a blade fuse 10 (hereinafter referred to as "fuse 10") according to a non-limiting embodiment of the present disclosure. Fuse 10 may include a laminated fuse body 12 having a plurality of electrically insulating layers and conductive layers arranged in a stacked arrangement. The multiple layers may include a first floating lead support layer 18; a first floating lead 20a and a second floating lead 20b disposed in a spaced-apart arrangement on the first floating lead support layer 18 to define a gap therebetween; a second floating lead support layer 22 disposed on the first floating lead 20a and the second floating lead 20b; a third floating lead 24a and a fourth floating lead 24b disposed in a spaced-apart arrangement on the second floating lead support layer 22 to define a gap therebetween; a plurality of barrier layers 28, 30 disposed on the third floating lead 24a and the fourth floating lead 24b; a first fuse support layer 34 disposed on top of the uppermost barrier layer 30; a first fuse layer 36 disposed on top of the first fuse support layer 34; a second fuse support layer 38 disposed on top of the first fuse layer 36; and a second fuse layer 40 disposed on top of the second fuse support layer 38.

[0014] The first floating lead support layer 18, the second floating lead support layer 22, the barrier layers 28, 30, the first fuse support layer 34, and the second fuse support layer 38 may be formed of electrically insulating materials, including but not limited to FR-4, glass, ceramics (e.g., low temperature co-fired ceramics), etc. In various embodiments, the aforementioned electrically insulating layers may be formed of ceramic tape ("green tape"). The present disclosure is not limited in this regard. The first floating lead 20a, the second floating lead 20b, the third floating lead 24a, the fourth floating lead 24b, the first fuse layer 36, and the second fuse layer 40 may be formed of metals having good electrical and thermal conductivity, including but not limited to copper, tin, silver, various alloys, etc. In various embodiments, the aforementioned conductive layers may be formed of the same metal or different metals without limitation.

[0015] The first fuse layer 36 may include a first terminal portion 42a and a second terminal portion 42b connected by a fusible portion 44. Similarly, the second fuse layer 40 may include a first terminal portion 46a and a second terminal portion 46b connected by a fusible portion 48. In various embodiments, the fusible portions 44, 48 may be thinned, narrowed, or otherwise mechanically weakened relative to the respective first terminal portions 42a, 46a and second terminal portions 42b, 46b, and may be adapted to melt and separate when a predetermined fault condition occurs in the fuse 10, such as an overcurrent condition, in which an amount of current exceeding a predefined maximum current (i.e., the "rating" of the fuse 10) flows through the fusible portions 44, 48. As will be appreciated by one of ordinary skill in the art, the size, shape, construction, and material of the fusible portions 44, 48 may all have an impact on the rating of the fuse 10.

[0016] The fuse 10 may also include conductive first and second end terminals 50, 52 disposed on opposite longitudinal ends of the fuse body 12. The first end terminal 50 may be electrically connected to the first terminal portion 42a of the first fuse layer 36 and the first terminal portion 46a of the second fuse layer 40. Similarly, the second end terminal 52 may be electrically connected to the second terminal portion 42b of the first fuse layer 36 and the second terminal portion 46b of the second fuse layer 40. As will be appreciated by those skilled in the art, the first and second end terminals 50, 52 may be formed from multiple layers of conductive material that may be applied to the fuse body 12 using a continuous dipping and plating process. For example, the first and second end terminals 50, 52 may include respective first layers 50a, 52a that may be formed by dipping opposite ends of the fuse body 12 into a metal slurry (e.g., a silver slurry) that is thereafter dried and sintered. The first end terminal 50 and the second end terminal 52 may also include a respective second layer 50b, 52b applied over the first layer 50a, 52a, the second layer 50b, 52b being formed of another metal (e.g., nickel) and being applied using an electroplating process. The first end terminal 50 and the second end terminal 52 may also include a respective third layer 50c, 52c applied over the second layer 50b, 52b, the third layer 50c, 52c being formed of another metal (e.g., tin) and being applied using an electroplating process. The present disclosure is not limited in this regard.

[0017] The fuse 10 may further include a protective layer 56 formed of epoxy resin, glass or other insulating materials disposed on the second fuse layer 40. The protective layer 56 may shield the second fuse layer 40 from external contaminants and may prevent electrical short circuits between the second fuse layer 40 and surrounding electronic components.

[0018] During normal operation of the fuse 10, current may flow from the first end terminal 50 to the second end terminal 52 through the first fuse layer 36 and the second fuse layer 40, and vice versa. If the fuse 10 is operated at a high amperage (e.g., 20A or higher), the current may generate a large amount of heat in the fuse body 12. In addition, when an overcurrent condition occurs in the fuse 10, the fusible portions 44, 48 of the first fuse layer 36 and the second fuse layer 40 may melt and separate, and arcs may propagate between the separated portions of the fusible portions 44, 48. Even if the fuse 10 carries a relatively low amperage (e.g., less than 20A) during normal operation, these arcs may generate a large amount of heat in the fuse body 12. If the heat in the fuse 10 is not reduced, it may cause damage to the fuse body 12 and / or surrounding components. Advantageously, the first and second floating leads 20a, 20b and the third and fourth floating leads 24a, 24b can act as heat sinks that absorb heat in the fuse 10 and promote the dissipation of heat through the first and second end terminals 50, 52, thereby attenuating the surface temperature rise in the fuse body 12 during both normal operation and overcurrent conditions. Therefore, the risk of burning and / or rupture of the fuse body 12, as well as the risk of damage to surrounding components, is reduced. In addition, the first and second floating leads 20a, 20b and the third and fourth floating leads 24a, 24b formed of metal can provide structural reinforcement for the fuse body 12, thereby enhancing the strength of the fuse body 12 and further reducing the risk of rupture / breakage. Therefore, the fuse 10 can exhibit a lower operating temperature and better breaking capacity relative to a blade fuse having a similar form factor.

[0019] The first floating lead 20a and the second floating lead 20b and the third floating lead 24a and the fourth floating lead 24b are connected to the Figure 1B 2 and 3. This is not intended to be limiting, and it is contemplated that the first and second floating leads 20a, 20b and the third and fourth floating leads 24a, 24b may be implemented with a variety of alternative shapes without departing from the scope of the present disclosure. Figure 2 and Figure 3 Non-limiting examples of such alternative shapes are provided in .

[0020] As used herein, elements or operations described in the singular and beginning with the word "a" or "an" should be understood as not excluding elements or operations in the plural form, unless such exclusion is explicitly stated. In addition, reference to "one embodiment" of the present disclosure is not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the described features.

[0021] Although the present disclosure refers to certain embodiments, many modifications, changes and variations of the described embodiments are possible without departing from the field and scope of the present disclosure, as defined in the appended claims. Therefore, it is intended that the present disclosure not be limited to the described embodiments, but rather have the full scope defined by the following claims and their equivalents.

Claims

1. A sheet-type fuse, comprising: A fuse body, the fuse body comprising: an electrically insulating floating lead support layer; a metallic first floating lead and a second floating lead, the first floating lead and the second floating lead being disposed atop the floating lead support layer in a spaced-apart arrangement so as to define a gap therebetween; an electrically insulating barrier layer disposed atop the first floating lead and the second floating lead; an electrically insulating fuse support layer disposed atop the barrier layer; and A conductive fuse layer, which is arranged on the top of the fuse supporting layer, and the fuse layer includes a first terminal part and a second terminal part connected by a fusible part; and a conductive first end terminal and a second end terminal, the first end terminal and the second end terminal are arranged on opposite ends of the fuse body, wherein the first end terminal is electrically connected to the first terminal part, and wherein the second end terminal is electrically connected to the second terminal part.

2. The sheet-type fuse according to claim 1, wherein: An outer insulating layer, the floating lead support layer, the barrier layer, and the fuse support layer are formed of a ceramic tape.

3. The sheet-type fuse according to claim 1, further comprising: A first mask layer is disposed on the fuse layer and a second mask layer is disposed on a bottom of the outer insulating layer.

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