Welded Bobbin EVAP Purge Solenoid Valve for Leak-Proof Sealing
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Solution Overview
Problem
Conventional solenoid valves suffer from internal leakage due to snap-fitted bobbins, leading to faulty EVAP systems and increased emissions, as the seals deteriorate over time and fail to provide a complete material bond.
Innovation Solution
A solenoid valve with a sealed bobbin is created by forming a permanent weld at the top and bottom of the bobbin and over molding housing, using methods like micro-melting or laser welding, to eliminate all potential leakage paths and ensure a complete material bond.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If snap-fitted bobbins are used in conventional solenoid valves, then the manufacturing process is simple and easy to assemble, but internal leakage occurs over time due to seal deterioration and loose fittings
Solution Approach 1:
The patent replaces the mechanical snap-fit attachment system with a welding system. The bobbin is permanently attached to the housing through welding, eliminating the mechanical connection that deteriorates over time. This substitution of mechanical attachment with thermal bonding resolves the contradiction by providing permanent, reliable sealing without requiring complex assembly mechanisms.
Solution Approach 2:
The patent merges the bobbin and housing into a single integrated structure through welding. By permanently joining these two components, the design eliminates the interface between separate parts where leakage could occur. This merging resolves the contradiction by creating a unified structure that maintains seal integrity over time while keeping the manufacturing process straightforward.
2Manufacturing precision
If snap-fitted bobbins are used in conventional solenoid valves, then the manufacturing process is simple, but misalignment between parts occurs leading to faulty operation
Solution Approach 1:
By welding the bobbin to the housing, the patent merges these components into a permanently aligned structure. The welding process itself ensures precise alignment as the components are joined in their final positions, eliminating misalignment issues. This resolves the contradiction by making alignment accuracy inherent to the manufacturing process rather than requiring separate alignment steps.
Solution Approach 2:
The patent applies preliminary action by performing the welding operation that permanently fixes the bobbin alignment before final assembly completion. The alignment is established and locked in during the welding process itself, preventing any subsequent misalignment. This preliminary fixation resolves the contradiction by ensuring precision is achieved early in the manufacturing sequence.
3Duration of action of stationary object
If snap-fitted seals are used in conventional solenoid valves, then the initial assembly is easy, but the seals become loose after prolonged usage and engine vibration
Solution Approach 1:
The patent replaces the mechanical snap-fit system with a welding system that creates permanent bonds. This substitution eliminates the problem of seals becoming loose under vibration and prolonged use, as the welded joint does not deteriorate over time. The manufacturing complexity increases slightly due to welding requirements, but this is offset by the elimination of future maintenance and replacement needs.
Solution Approach 2:
The welding process provides beforehand cushioning by creating a permanent, vibration-resistant bond between the bobbin and housing before the valve is subjected to engine vibrations. This pre-established strong connection prevents the seal deterioration that would otherwise occur during service. The slight increase in manufacturing complexity is justified by the significant extension of service life.
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
The solution effectively prevents internal and external leakage, enhancing the longevity and performance of the solenoid valve by ensuring a robust seal, thereby reducing emissions and evaporations.
Implementation Method 1
creating a permanent weld at the top of bobbin and over molding housing
Implementation Method 2
preferably but not limited to method such as Micro-Melting
Implementation Method 3
completely laser welded nozzle and housing
Data Source
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AI summary
A leak proof solenoid valve, comprising a housing (14) having a fluid flow path controlled via an electrically operated mechanism to control a flow; the mechanism comprises metallic coil (20) coiled around a bobbin (16) supported by a magnetic bracket (24) with terminal pins (18) connected to the bobbin (16) for receiving electrical input to facilitate an energized and de-energized state to control the movement of a poppet (34) shaft that obstructs the flow; wherein, the bobbin (16) comprises micro-melting fins, thereby housing over molding creates strong bond between two materials; a permanent weld is created between the bobbin (16) and the housing (14) to prevent internal leakage.