阅读说明：本技术 用于制造密封汽车电气保险丝盒的工艺 (Process for manufacturing sealed automotive electrical fuse box ) 是由 迈克尔·斯克日普扎克 基思·尤兹维克 于 2021-05-14 设计创作，主要内容包括：一种保险丝装配件,包括连接到两个母线的保险丝、注射成型的基座和注射成型的覆盖件。母线被粉末涂覆有粉末基粘合剂或粘合促进剂,然后在烘箱中固化。然后将母线放置在注射成型设备的模腔图像中。塑料被加热成液体形式,并被注射到模腔图像中。所得到的注射成型的基座既防尘又防水,从而保护内部的保险丝。(A fuse assembly includes a fuse connected to two bus bars, an injection molded base, and an injection molded cover. The bus bars are powder coated with a powder-based binder or adhesion promoter and then cured in an oven. The bus bars are then placed in a cavity image of the injection molding apparatus. The plastic is heated to a liquid form and injected into the mold cavity image. The resulting injection molded base is both dust and water proof, protecting the internal fuse.)

1. An injection molded base for producing a fuse assembly prepared by a process comprising the steps of:

covering a portion of the bus bar with a sealant;

inserting the bus bar into a cavity image of an injection molding apparatus, wherein the portion of the bus bar is inside the cavity image;

injecting molten plastic into the mold cavity image; and

removing the injection molded base from the mold cavity image.

2. The injection molded base of claim 1, the process further comprising the steps of:

powder coating the portion of the bus bar with the sealant, the sealant comprising a powder; and

curing the bus bar in an oven until the sealant is cured on the portion.

3. The injection molded base of claim 1, the process further comprising the step of cooling the mold cavity image prior to removing the injection molded base from the mold cavity image.

4. The injection molded base of claim 1, the process further comprising the steps of:

mixing the plastic pellets with a pigment; and

adding the plastic pellets to a hopper of the injection molding apparatus.

5. The injection molded base of claim 1, the process further comprising the steps of:

covering a second portion of a second bus bar with the sealant;

inserting the second busbar into the cavity image, wherein a second portion of the second busbar is inside the cavity image.

6. The injection molded base of claim 1, the process further comprising the steps of:

cleaning the bus bar with a cleaning agent; and

covering the bus bar except for the portion with a masking tape.

7. The injection molded base of claim 1, the process further comprising the steps of:

covering the portion of the bus bar with the sealant until the sealant forms a layer between 52 and 94 μm thick on the bus bar.

8. A method of manufacturing a fuse assembly, comprising:

coating a bus bar with a sealant, the sealant comprising a powder;

baking the bus bar in an oven until the sealant cures onto the bus bar;

inserting the bus bar into a cavity image of an injection molding apparatus, wherein a portion of the bus bar is inside the cavity image;

filling the mold cavity image with molten plastic at high pressure, wherein the molten plastic and the sealant form a bonded material such that the bonded material cannot be separated by a subsequent heating operation; and

removing the plastic base of the fuse assembly and the bus bar from the mold cavity image.

9. The method of making a fuse assembly of claim 8, further comprising powder coating said busbars with between 52 and 94 μ ι η of sealant, wherein said busbars are electrically grounded to a powder coating gun.

10. The method of manufacturing a fuse assembly according to claim 8, further comprising:

mixing the plastic pellets with a pigment to form colored plastic pellets; and

adding the colored plastic pellets to a hopper of the injection molding apparatus, wherein the colored plastic pellets become molten plastic upon application of heat.

11. The method of manufacturing a fuse assembly according to claim 8, further comprising:

coating a second bus bar with the sealant; and

inserting the second busbar into the cavity image after the second busbar and the sealant are cured.

12. The method of manufacturing a fuse assembly according to claim 11, further comprising:

inserting a fuse into the plastic base, the fuse including a first terminal and a second terminal; and

attaching the first terminal to the bus bar; and

attaching the second terminal to the second bus bar.

13. The method of making a fuse assembly according to claim 11, further comprising cleaning the busbar and the second busbar with a degreaser.

14. A fuse assembly comprising:

a fuse;

a first bus bar for establishing a first electrical connection between an electrical circuit and a first side of the fuse;

a second bus bar for establishing a second electrical connection between the circuit and a second side of the fuse; and

an injection molded base comprising a first opening through which the first busbar is disposed and a second opening through which the second busbar is disposed, wherein the injection molded base is manufactured by:

covering a first portion of the first bus bar with a sealant;

covering a second portion of the second bus bar with the sealant;

inserting the first and second bus bars into a cavity image of an injection molding apparatus, wherein the first and second portions are inside the cavity image; and

injecting hot molten plastic into the mold cavity image,

wherein the sealant fills the first opening and the second opening.

15. The fuse assembly of claim 14, wherein the injection molded base is further manufactured by:

covering the first bus bar except the first portion with a masking tape; and

covering the second bus bar except for the second part with a masking tape; wherein the sealant covers only the first portion and the second portion.

16. The fuse assembly of claim 14, wherein the injection molded base is further manufactured by:

allowing the injection molded base to cool while in the mold cavity image; and

removing the injection molded base, the first bus bar, and the second bus bar from the mold cavity image.

17. The fuse assembly of claim 14, wherein the injection molded base is further manufactured by powder coating the sealant on the first and second portions, wherein the sealant is in powder form.

18. The fuse assembly of claim 17, wherein the sealant is cured on the first and second portions by baking the first and second bus bars in an oven.

19. The fuse assembly of claim 18, wherein said oven temperature is between 180 to 200 ℃ and said bus bar is heated for 5 to 17 minutes.

20. The fuse assembly of claim 19, wherein the sealant when cured is between 52 and 94 μ ι η on the first and second busbars.

Technical Field

Embodiments of the present disclosure relate to the field of fuses, and more particularly, to a dust-proof and moisture-proof fuse housing (enclosure).

Background

Fuses are used in various circuits to protect electronic components from overcurrent events. Fuses come in a variety of shapes and sizes. For certain applications (such as circuit protection in extreme environments), the fuse may be contained in a closed structure, referred to as an electrical fuse box. Although fuses are contained therein, it is a continuing challenge to ensure that the fuses are not damaged in such extreme environments, such as by dust or moisture entering the electrical fuse box.

In view of these and other considerations, current improvements may be useful.

Disclosure of Invention

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

In various embodiments, an injection molded base for producing a fuse assembly (assembly) is prepared by a process comprising the steps of: covering a portion of the bus bar with a sealant; inserting a bus bar into a cavity image of an injection molding apparatus, wherein the portion of the bus bar is inside the cavity image; injecting molten plastic into the mold cavity image; and removing the injection molded base from the mold cavity image.

In one embodiment, a method of manufacturing a fuse assembly according to the present invention comprises: coating the bus bar with a sealant, the sealant comprising a powder; baking the bus bar in an oven until the sealant is cured on the bus bar; inserting a bus bar into a cavity image of an injection molding apparatus, wherein a portion of the bus bar is inside the cavity image; filling the mold cavity image with molten plastic at high pressure, wherein the molten plastic and sealant form an adhesive material that cannot be subsequently separated by heating; and removing the plastic base and the bus bar of the fuse assembly from the mold cavity image.

In another embodiment, a fuse assembly according to the present disclosure includes: a fuse; a first bus bar for establishing a first electrical connection between the circuit and a first side of the fuse; a second bus bar for establishing a second electrical connection between the circuit and a second side of the fuse; and an injection molded base including a first opening through which the first bus bar is disposed and a second opening through which the second bus bar is disposed, wherein the injection molded base is manufactured by: covering a first portion of the first busbar with a sealant; covering a second portion of the second bus bar with a sealant; inserting the first and second bus bars into a cavity image of an injection molding apparatus, wherein the first and second portions are inside the cavity image; hot molten plastic is injected into the mold cavity image, wherein the sealant fills the first and second openings.

Drawings

Fig. 1 is a diagram illustrating an electrical fuse block according to an exemplary embodiment of the present disclosure;

FIG. 2 is a diagram illustrating an injection molded base of the electrical fuse box of FIG. 1 according to an exemplary embodiment;

fig. 3A and 3B are diagrams illustrating fuses of the electrical fuse block of fig. 1 according to exemplary embodiments of the present disclosure;

fig. 4 is a diagram illustrating a bus bar of the electrical fuse box of fig. 1 according to an exemplary embodiment of the present disclosure;

fig. 5 is a flowchart illustrating process steps for manufacturing a base of the electrical fuse box of fig. 1 according to an exemplary embodiment of the present disclosure.

Detailed Description

A method of manufacturing a dust and moisture resistant fuse assembly in accordance with the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the disclosure are shown. The methods of the present disclosure may, however, 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 this disclosure will convey certain exemplary aspects of the method to those skilled in the art.

Referring to fig. 1, a representative diagram of an electrical fuse assembly 100 according to an exemplary embodiment is shown. The electrical fuse assembly 100 (hereinafter "fuse assembly 100") generally includes two bus bars 102A and 102B (collectively "bus bars 102"), a fuse housing 104, terminals 118A, 118B, a base 106, a sealant 108, and a cover 110. The base 106 and cover 110 form an outer shell of the fusible element of the fuse assembly 100. Bus bar 102 is surrounded by encapsulant 108, where encapsulant 108 is visible in opening 112B of base 106. Bus bar 102B occupies opening 112B. The bus bar 102A occupies a second opening 112A (a portion of which is shown) (collectively referred to as "openings 112"). In the exemplary embodiment, openings 112 are rectangular and respective bus bars 102 are disposed therethrough, although openings 112 may take on a variety of different shapes. As will be shown, the base 106 is an injection molded structure formed around the bus bar 102.

The bus bar 102 may be made of a variety of conductive materials, including but not limited to copper, tin, silver, zinc, aluminum, alloys comprising these materials, or combinations thereof. The bus bar 102 may be positioned at an end of the fuse assembly 100, for example, where a first bus bar 102A is disposed at a first end 114 of the base 106 and a second bus bar 102B is disposed at a second end 116 of the base 106. The bus bars 102A, 102B extend through the base 106 via respective openings 112A, 112B (collectively "openings 112"), and are electrically connected to respective terminals 118A, 118B (collectively "terminals 118"). For example, first bus bar 102A extends through opening 112A of base 106 and is connected to terminal 118A, while second bus bar 102B extends through opening 112B of base 106 and is connected to terminal 118B.

Fig. 2 is a representative view of an injection molded base 106 of the fuse assembly 100 of fig. 1 according to an exemplary embodiment. The base 106 includes a bottom portion 202 and a top portion 204, wherein the opening or void 112 forms a mold cavity within the bottom portion. Both the bottom portion 202 and the top portion 204 are rounded rectangular cubes, although they may be shaped differently without departing from the scope of the present disclosure. The bottom portion 202 is adapted to receive the bus bar 102. The skeletal lines indicate that the bus bar 102A occupies the left opening 112A of the bottom portion 202 of the base 106 from the left. Similarly, the bus bar 102B occupies the right opening 112B of the bottom portion 202 of the base 106 from the right. The top portion 204 is for receiving the fuse housing 104 including the terminals 118 and for attaching the fuse cover 110. The fuse housing 104 is inserted into the opening 206 of the base 106.

Fig. 3A and 3B are representative diagrams of the fuse assembly 100 of fig. 1, according to an example embodiment.

Fig. 3A shows another view 100A of the fuse housing 104 and the terminals 118 that have been introduced according to an exemplary embodiment, while fig. 3B shows a fusible element assembly 300 made of exposed fusible elements 310, terminals 118A and terminals 118B (which are part of the fuse assembly 100 of fig. 1).

Fig. 3A shows the fuse housing 104 and the terminals 118, while fig. 3B shows the exposed fusible element 310 disposed below the fuse housing 104. As described above, the fuse assembly 100 is an electrical safety device inserted into an electronic circuit for overcurrent protection. The fusible element 310 of the fuse assembly 100 is a breakable portion, such as a wire or a ribbon, adapted to melt or otherwise separate when an amount of current exceeding the current rating of the fuse assembly 100 flows through the fusible element 310. Thus, in the event of an overcurrent, current flow through the fuse assembly 100 is prevented, thus protecting the connected electrical components. In the illustration of fig. 3A, the fuse housing 104 hides the fusible element 310 of the fusible element assembly 300 from view.

As shown in fig. 3B, the fusible element assembly 300 also includes a left terminal 118A and a right terminal 118B. The fusible element 310 is disposed between the left terminal 118A and the right terminal 118B. Like the bus bar 102, the terminal 118 is made of a conductive material, such as metal, which enables the fusible element 310 to be electrically connected to the rest of the protected circuit. Thus, the left terminal 118A is connected to a left side portion of the fusible element 310, while the right terminal 118B is connected to a right side portion of the fusible element 310, which is hidden from view by the fuse housing 302 in fig. 3A, but is visible in fig. 3B.

The terminals 118 also include apertures for connecting the fusible element assembly 300 to the fuse housing 104. Terminal 118A includes apertures 312A and 312B, while terminal 118B includes apertures 314C and 314D (collectively, "apertures 312"). Similarly, as shown in FIG. 3A, the fuse housing 104 includes apertures 314A-D (collectively, "apertures 314"). The apertures 312 of the fusible element assembly 300 are aligned with corresponding apertures 314 of the fuse housing 104 so that the terminals 118 can be connected to the fuse housing 104, such as by placing screws or bolts through the apertures 312, 314. The fuse housing 104 may be comprised of a top portion and a bottom portion with the fusible element assembly 300 sandwiched between the fuse housing 104.

During normal operation of the fuse assembly 100, current flows from the bus bar 102A to the bus bar 102B (and vice versa) through the fuse element 310. During an abnormal condition (i.e., an overcurrent condition), the fusible element 310 may melt and separate, and an arc may propagate between the separated ends of the fusible element 310. The arc may vaporize a portion of the fusible element 310 within the fuse housing 104. The fusible element 310 may include multiple bends and curvatures, as shown. It should be understood that the shape of the fusible element 310 may be varied to suit the desired application such that during an arc discharge, the fusible element 310 quickly vaporizes and isolates protected circuit components to prevent or mitigate damage to these components.

In some embodiments, the terminals 118 have respective connecting holes or apertures 306A, 306B (collectively "apertures 306") for coupling to respective bus bars 102. The apertures 306 may be configured to physically and electrically connect the fuse assembly 100 to power and circuit components. For example, the apertures 306 may be configured to receive cylindrical protrusions, such as bolts or posts. The bus bars 102 each have a respective input stud 308A, 308B (collectively "input studs 308") for fitting through the respective apertures 306. As shown in fig. 3A, the aperture 306A of the left terminal 118A of the fuse assembly 100 is positioned over the input stud 308A of the left busbar 102A; similarly, the aperture 306B of the right terminal 118B is positioned above the input stud 308B of the right bus bar 102B. Although the aperture 306 is circular and the input stud 308 is cylindrical, the aperture 306 may be configured in any shape to receive any shape of bolt, post, or other retaining/connecting structure.

The terminals 118 are configured to electrically connect the fuse assembly 100 to a power source (not shown) and a circuit component (not shown) to be protected. The fusible element 310 bridges and electrically connects the terminals 118. In some embodiments, the fusible element 310 is made of the same conductive material as the terminals 118, including, for example, copper, tin, silver, zinc, aluminum. In other embodiments, the terminals 118 are made of a different material than the fuse element 310. The fuse element 310 may be shaped in any known configuration for providing circuit interruption, including but not limited to a wire, a metal link, and an element shaped as a plurality of bends and/or curves. Various techniques for forming the fusible element assembly 300 are known, including but not limited to stamping, cutting, and printing, and may include forming the fusible element 310 and the terminals 118 separately or as a single piece. If the fusible element 310 and the terminal 118 are separately formed (i.e., in separate pieces), the pieces may then be joined together using various techniques, including, for example, brazing, welding, and other known joining processes.

In the illustrations 300A, 300B, the terminals 118 are generally flat pieces of metal; similarly, the bus bar 102 is a generally flat piece of metal. Once the bus bar 102 is in place within the base 106 of the fuse assembly 100, the process of which will be described below, the fuse housing 104, including the left and right terminals 118, is placed such that the apertures 306 fit over the input studs 308. The fuse housing 104 is then pushed downward such that the terminals 118 and the bus bars 102 are coupled to each other with the input stud 308 of each bus bar 102 protruding from the respective aperture 306. In other words, one flat metal piece (terminal 304) is located on top of the second metal piece (bus bar 102) so that an electrical connection between the two metal pieces is possible.

In an exemplary embodiment, the base 106 and the cover 110 of the fuse assembly 100 are produced using an injection molding technique. Injection molding is a mechanism for mass producing plastic parts. Although the actual process is somewhat complicated, the heart of the injection molding technique is to heat the plastic pellets (pellets) until they melt and inject the molten material into the mold (this is the so-called cavity image). The cavity image is typically made of steel or other metallic material. Thus, both the injection molded base 106 and the injection molded cover 110 are made of a plastic material and are formed using injection molding techniques.

As described above, there are two bus bars 102, one on each side of the fuse housing 302 for connection to the fuse housing 104. As described above, these bus bars 102 are made of a metal material, such as copper or other materials. In addition to being connected to the fuse housing 302 as shown in fig. 3A and 3B, the bus bar 102 also connects the fuse housing 104 to other components of the protected circuit (not shown). Since the base 106 is manufactured using an injection molding technique, the metal busbar 102 is inserted into the mold cavity image forming the base 106 before the molten plastic material is injected therein. The injected plastic material forms the shape of the base 106 according to the mold cavity image. Cooling bars disposed around the mold cavity image will cool and eventually solidify the injected plastic material into the shape of the base 106, with the metal bus bar 102 embedded in the base 106.

Metals have a higher surface energy, while plastics have a lower surface energy. These characteristics make it difficult for metals to adhere to plastics. Additionally, factors such as crystallinity and polarity affect the ability of plastics to bond. Materials with higher surface energy wet and adhere more easily than materials with lower surface energy. The combination of the metal busbar 102 and the plastic material of the fuse base 106, if not more, does not generally promote a watertight bond between the different materials.

The International Electrotechnical Commission (IEC) promulgates an Ingress Protection code (IP code) that classifies the degree of Protection provided by the electrical enclosure against the Ingress of dust and water. Electrical fuse boxes suitable for extreme environments in the automotive industry (e.g., for use with off-road vehicles, construction equipment, trucks, and buses) may have IP code requirements. The first number of the IP code indicates the level of protection against solid particles, while the second number indicates that liquid enters the protection. For example, enclosures listed under the IP67 standard are considered "dust tight" and do not allow dust to enter the enclosure ("6" parts) while also being water tight, despite the enclosure being immersed in water up to 1 meter for 30 minutes ("7" parts).

In an exemplary embodiment, the metal bus bar 102 of the fuse assembly 100 is partially coated with the sealant material 108 shown in fig. 1 before being inserted into the mold cavity image of the injection molding machine. The sealant 108 enables a more effective bond to be formed between the busbar 102 and the base 106 of the fuse assembly 100. In the exemplary embodiment, sealant 108 is powder coated onto bus bar 102.

Powder coating is a process for applying material, typically in powder form, to metal parts. The powder coating operation uses a powder coating gun connected to an air compressor. The emitter rod in the gun charges the air in the front of the gun. The compressed air moves the powder out of the gun, the powder passes through the charged air, and a high voltage charge is charged. As these charged particles move through the air, they are attracted to the metal part being powder coated, which is grounded by a ground lead attached to the powder coating gun. The electrical attraction causes the powder particles to completely coat the surface of the metal. The metal part is then baked in an oven to cure the coating.

Powder coatings are considered to be superior to conventional coatings when used with metal parts. In an exemplary embodiment, the sealant 108 is a powder material and the metal busbar 102 of the fuse assembly 100 is powder coated with the sealant 108. The powder coating process ensures a tight bond between the metal of the busbar 102 and the sealant 108. Once the powder coated sealant 108 is cured on the bus bar 102, the sealant is considered to adhere to the bus bar 102. The bus bar 102 is then ready to be placed in the mold cavity image to form the pedestal 106. The subsequent injection molding operation fills the mold cavity image with the plastic material that makes up the base 106 of the fuse assembly 100.

The injection molding process involves injecting heated liquid plastic into the mold cavity image. First, the plastic pellets to be melted may be combined with a pigment or other material before being fed into the hopper of an injection molding machine. From the hopper, the plastic pellets enter a cylindrical chamber surrounded by heating elements which start to melt the plastic. Further, a reciprocating screw within the cylindrical chamber helps to uniformly heat and transport the pellets through the chamber toward the mold cavity image. At the end of the cavity, molten plastic is injected into the mold cavity image, which in this application includes the bus bar 102. The portion of the busbar 102 that has been coated with the cured sealant 108 is thus surrounded by molten plastic, which will eventually form the base 106 of the fuse assembly 100. The cooling chamber surrounds the mold cavity image to cool the plastic base 106. Finally, the cooled plastic base 106 (including the sealant-cured bus bar 102) is released from the mold cavity image.

During the curing step of the powder coating process, a tight bond is formed between the metal of the busbar 102 and the sealant 108. Further, once the plastic base 106 surrounding the bus bars cools in the injection molding operation, a tight bond is also formed between the sealant 108 and the plastic of the base 106. Further, in the exemplary embodiment, the heat and pressure of the injection molding process enhance the adhesive ability of encapsulant 108. In one embodiment, the combination of pressure and heat of the injection molding process creates an environment in which the plastic of the base 106 and the sealant 108 cross-link with each other, thereby forming a strong bond. The resulting bonded materials cannot be separated by a subsequent heating operation, since the materials have irreversibly hardened from each other and cannot be melted. The sealant 108 thus allows two different materials (metal and plastic) to form a tight bond within the fuse assembly 100. In an exemplary embodiment, the combination of metal (from the bus bar), sealant and plastic (of the base) is dust and moisture resistant. In one embodiment, the combination of metal, sealant and plastic forms a seal that makes the fuse assembly 100 compliant with IP 67.

Fig. 4 is a representative diagram of a left busbar 102A such as used in the fuse assembly 100 of fig. 1, according to an example embodiment. This figure shows that the bus bar 102A is a single piece of metal, which is generally an elongated rectangular cuboid having two cylindrical input studs 402 and 308A, the latter of which are connected to the terminals 118A (fig. 3A and 3B) of the fuse housing 104. The input studs 402 can be electrically connected to the circuit to be protected in a manner similar to how the bus bars 102 are connected to the respective terminals 118, as described above.

Outside of the fuse assembly 100, the bus bar 102A is an elongated metal piece with two input studs 402 and 308A at either end for connection to the circuit and fuse housing 104, respectively, as described above. A portion 406 (shaded) of the busbar 102A is the portion of the busbar that will be embedded in the plastic material of the base 106. To the left of the portion 406, the bus bar 102A is external to the base 106 of the fuse assembly 100 (see, e.g., fig. 1). To the right of the portion 406, the bus bar 102A is visible in the opening 206 of the base 106 in which the fuse housing 104 and the terminal 118 will be placed. In an exemplary embodiment, only a portion 406 of the bus bar 102A is powder coated with the sealant 108, such as to save cost. In another embodiment, the entire rectangular portion of the bus bar 102A is powder coated with the sealant 108, but the input studs 402 and 308A are not powder coated. The bus bar 102A may be freely coated with the sealant 108 as long as the sealant 108 does not interfere with the connection points so as to prevent metal-to-metal contact between the bus bar and the circuit (at one end) and its respective fuse terminal (at the other end). Powder coating of the bus bar 102A at the location where the bus bar 102A is surrounded by the plastic material results in a metal-sealant-plastic bond that makes the fuse assembly 100 both dust and water resistant.

In one embodiment, the sealant 108 used to make the fuse assembly 100 is a powder-based adhesive, in other words, an in-mold adhesive, that may be used with an injection molding operation. In another embodiment, encapsulant 108 is a heat activated epoxy that is available in powder form. In yet another embodiment, the sealant 108 is a spray adhesive that is pressure activated and heat activated. In another embodiment, sealant 108 is a crosslinkable adhesion promoter for metal-plastic hybrid parts, such as the commercially available product manufactured by EvonikHylink。

FIG. 5 is a flowchart of process steps for constructing the fuse assembly of FIG. 1, according to an exemplary embodiment. Bus 102 first needs to be cleaned, such as by using a degreaser, such as isopropyl alcohol or acetone (block 502). This provides bus bar 102 with a substantially chemically uniform surface, which promotes adhesion. Further, to avoid contact with skin oils, rubber gloves or treatment tools should be used in treating the bus bars. In the case where portions of the bus bar are not powder coated, these portions are first covered, such as by using masking tape (block 504). Selected (uncovered) portions of each of the bus bars 102 are then powder coated with the powder sealant 108 (block 506). In an exemplary embodiment, the coating thickness is between 52 and 94 μm. In an exemplary embodiment, the powder sealant 108 is applied to the portion of the bus bar 102 that will be covered in the plastic material comprising the injection mold base 106, such as the portion 406 shown in fig. 4. Once the powder coatings are applied to the bus bars 102, they are heated in an oven or other heating device (block 508). In an exemplary embodiment, the bus bar is heated at 180 to 200 ℃ for 5 to 17 minutes, and when the melting is completed, the color of the sealant should change from white to transparent. Due to the curing process, a tight bond will be formed between the sealant material 108 and the metal of the bus bar 102. Optimally, until the bus bar is transported to the injection molding apparatus, the bus bar is stored in a way that protects the coated part from particulates or any other form of contamination.

Once the cured sealant is part of the bus bars 102, they are inserted into a mold cavity image of an injection molding apparatus (block 510). Because each fuse assembly 100 includes two bus bars 102, two bus bars 102 will be inserted inside each mold cavity image. In the exemplary embodiment, only the portion of each bus bar 102 that is covered with the cured sealant (such as portion 406) is positioned inside the cavity image, while the remainder of the bus bar 102 is positioned outside the cavity image. The plastic pellets that become the base 106 of the fuse assembly 100 are then deposited into the hopper of the injection molding machine (block 512). The plastic pellets may be mixed with small amounts of pigments or other materials known as colorants. The injection molding apparatus heats the plastic pellets until they are in fluid form. The fluid plastic is then injected into the mold cavity image (block 514). The high pressure thermoplastic reacts with the sealant on the bus bar 102 to form an adhesive bond between the sealant 108 and the plastic (block 516). A cooling tube or other device surrounding the mold cavity image allows the pedestal 106 within the mold cavity image to cool (block 518). Finally, the base 106 is removed from the mold cavity image, including the embedded bus bar 102 with the powder coated sealant portion 108 (block 520). A tight bond between the powder coated sealant 108 forming the bus bar 102 and the plastic material forming the base 106. The method steps of fig. 5 may be applied to virtually any device in which a metal busbar is overmolded with a plastic material as described herein, in addition to the fuse assembly 100 of fig. 1.

Thus, a method of manufacturing a dust and moisture resistant fuse assembly is disclosed according to an exemplary embodiment. By performing a powder coating operation on a portion of the bus bar within the assembly, a sealant is deposited on the bus bar, thereby forming a tight bond or seal between the metal of the bus bar and the sealant. Further, by including the bus bar in the cavity image of the injection mold apparatus, the plastic forming the base of the fuse assembly surrounds the portion of the bus bar that has been cured by the sealant, thus forming a tight bond or seal between the sealant and the plastic material of the fuse assembly base. Finally, the tight bond or seal between the metal, sealant and plastic makes the fuse assembly both dust and moisture resistant and, in the exemplary embodiment, IP67 compliant.

As used herein, an element or step recited in the singular and proceeded with the word "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 the recited features.

Although the present disclosure makes reference to certain embodiments, many modifications, alterations, and changes to the described embodiments are possible without departing from the scope and ambit of the present disclosure as defined in the appended claim(s). Accordingly, it is intended that the disclosure not be limited to the described embodiments, but that it have the full scope defined by the language of the following claims, and equivalents thereof.