Fuel Pump Plug Encapsulation Using Base Plate and Mold Cores
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for producing plugs with plastic injection-molded encapsulation for fuel pumps in motor vehicle fuel tanks often result in electrical components coming into contact with the injection mold cavity walls, leading to potential leakage, especially with aggressive fuels like methanol or ethanol, which can damage components. This issue is exacerbated by the need for thicker walls to prevent leakage, increasing weight and size.
Innovation Solution
A method involving a base plate with pre-mounted electrical components, inserted into an injection mold with protruding cores that maintain a distance from the cavity walls, allowing plastic to flow reliably and preventing contact during encapsulation, with cores being retracted as the plastic solidifies to ensure secure encapsulation and prevent leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the plastic injection-molded encapsulation is designed with thicker walls to prevent leakage, then the reliability against fuel leakage is improved, but the weight and physical size increase
Solution Approach 1:
The electrical components are fixed on the base plate before injection molding, establishing their positions in advance. This preliminary arrangement prevents components from moving during the injection process, eliminating the need for thicker encapsulation walls to prevent leakage, thus maintaining both reliability and lightweight design
Solution Approach 2:
The base plate serves as an intermediary component that provides a stable mounting surface for electrical components. By fixing components to the base plate first, the system ensures proper positioning and spacing from the injection mold cavity wall, preventing fuel leakage without requiring excessive encapsulation thickness
2Reliability
If the plastic injection-molded encapsulation is designed with thicker walls to prevent leakage, then the reliability against fuel leakage is improved, but the physical size increases
Solution Approach 1:
The electrical components are fixed on the base plate before injection molding, establishing their positions in advance. This preliminary arrangement prevents components from moving during the injection process, eliminating the need for thicker encapsulation walls to prevent leakage, thus maintaining both reliability and compact size
Solution Approach 2:
The base plate serves as an intermediary component that provides a stable mounting surface for electrical components. By fixing components to the base plate first, the system ensures proper positioning and spacing from the injection mold cavity wall, preventing fuel leakage without requiring excessive encapsulation thickness
3Ease of manufacture
If electrical components are allowed to move freely in the injection mold cavity, then the ease of manufacture is improved, but the reliability against leakage deteriorates
Solution Approach 1:
The electrical components are fixed on the base plate before injection molding, establishing their positions in advance. This preliminary arrangement prevents components from moving during the injection process, eliminating the need for thicker encapsulation walls to prevent leakage, thus maintaining both reliability and lightweight design
Solution Approach 2:
The base plate serves as an intermediary component that provides a stable mounting surface for electrical components. By fixing components to the base plate first, the system ensures proper positioning and spacing from the injection mold cavity wall, preventing fuel leakage without requiring excessive encapsulation thickness
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively prevents leakage to electrical components, allowing for a smaller and lighter plug design while ensuring reliable encapsulation of all components, including those on the base plate, such as capacitors and ground contacts, with simplified assembly and reduced component count.
Implementation Method 1
the cavity of the now-closed injection mold is then filled with a plastic
Implementation Method 2
the cores are pushed out of the cavity into the or along the openings during the process of filling the cavity with the plastic
Data Source
AI summary
A method is provided for producing a plug, having a plastic injection-molded encapsulation, for a fuel pump which arranged in a fuel tank of a motor vehicle. The plug has cables, stranded wires and a ground contact each protruding out of the encapsulation and each connected to encapsulated components. The plug elements and coils are inserted into a base plate. One core of a cable is soldered, welded or crimped to flat plug elements. The coils and stranded wires are each soldered, welded or crimped to a flat plug element. The base plate is inserted into a cavity of an injection mold, such that the cables and the stranded wires protrude out of the cavity through first passage openings and second passage openings, respectively, and cores are arranged in continuous openings of identical cross section in the wall of the injection mold. The cavity is then filled with a plastic.