Process for manufacturing sealed automotive electrical fuse box

Patent metadata

Field	Value
Publication number	US-11404234-B2
Application number	US-202015931761-A
Country	US
Kind code	B2
Filing date	May 14, 2020
Priority date	May 14, 2020
Publication date	Aug 2, 2022
Grant date	Aug 2, 2022

Abstract

A fuse assembly including a fuse connected to two busbars, an injection molded base and an injection molded cover. The busbars are powder-coating with a powder-based adhesive or adhesion promoter, then cured in an oven. The busbars are then placed in the cavity image of an injection molding apparatus. Plastic is heated to a liquid form and injected into the cavity image. The resulting injection molded base is resistant to both dust and water, protecting the fuse inside.

First claim

The invention claimed is:

1. An injection molded base for production of a fuse assembly, the injection molded base prepared by a process comprising the steps of:
covering a portion of a busbar with a sealant, wherein a first bond is formed between the busbar and the sealant;
inserting the busbar into a cavity image of an injection molding apparatus, wherein the portion of the busbar is inside the cavity image;
injecting melted plastic into the cavity image; and
removing the injection molded base from the cavity image, the injection molded base being formed from the melted plastic, wherein a second bond is formed between the injection molded base and the sealant;

wherein the first bond and the second bond form a seal that makes the fuse assembly IP 67-compliant.

2. The injection molded base of claim 1 , the process further comprising the steps of:
powder-coating the portion of a busbar with the sealant, the sealant comprising a powder; and
curing the busbar in an oven until the sealant is cured onto the portion.

3. The injection molded base of claim 1 , the process further comprising the steps of cooling the cavity image before removing the injection molded base from the cavity image.

4. The injection molded base of claim 1 , the process further comprising the steps of:
mixing plastic pellets with 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 busbar with the sealant;
inserting the second busbar into the cavity image, wherein the 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 busbar with a cleaning agent; and
covering the busbar except for the portion with masking tape.

7. The injection molded base of claim 1 , the process further comprising the steps of:
covering the portion of the busbar with the sealant until the sealant forms a layer of between 52 and 94 μm thick on the busbar.

8. A fuse assembly comprising:
a fuse;
a first busbar for establishing a first electrical connection between a circuit and a first side of the fuse;
a second busbar 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 busbar with a sealant;
covering a second portion of the second busbar with the sealant;
inserting the first busbar and the second busbar into a cavity image of an injection molding apparatus, wherein the first portion and the second portion are inside the cavity image; and
injecting hot melted plastic into the cavity image;

wherein the sealant fills the first and second openings.

9. The fuse assembly of claim 8 , wherein the injection molded base is further manufactured by:
covering the first busbar with masking tape except for the first portion; and
covering the second busbar with masking tape except for the second portion;

wherein the sealant only covers the first portion and the second portion.

10. The fuse assembly of claim 8 , wherein the injection molded base is further manufactured by:
allowing the injection molded base to cool while in the cavity image; and
removing the injection molded base, the first busbar, and the second busbar from the cavity image.

11. The fuse assembly of claim 8 , wherein the injection molded base is further manufactured by powder-coating the sealant over the first portion and the second portion, wherein the sealant is in powder form.

12. The fuse assembly of claim 11 , wherein the sealant is cured over the first portion and the second portion by baking the first busbar and the second busbar in an oven.

13. The fuse assembly of claim 12 , wherein the oven temperature is between 180-200° C. and the busbars are heated for 5-17 minutes.

14. The fuse assembly of claim 13 , wherein the sealant is between 52 and 94 μm on the first and second busbars when cured.

Assignees

• Littelfuse Inc

Inventors

• Skrzypczak Michael
• Jozwik Keith

Classifications

• H01H85/201 Primary

  for connecting a fuse in a lead and adapted to be supported by the lead alone · CPC title

• B29C45/14639 Primary

  for obtaining an insulating effect, e.g. for electrical components · CPC title

• B29C45/73

  of the mould {(B29C45/2642 and B29C45/2737 take precedence)} · CPC title

• B29C45/14008

  Inserting articles into the mould (B29C45/14827 takes precedence) · CPC title

• H01H2085/206

  being tappable, e.g. terminals on the fuse or base being arranged so as to permit an additional connector to be engaged therewith · CPC title