Laser Welded Flow Sensor Housing for Fuel Injector Sealing
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Solution Overview
Problem
Conventional flow sensors in electronically controlled fuel injectors face challenges with productivity, quality, and cost due to the use of thermosetting adhesives for sealing, which require long curing times, result in increased production costs, and are prone to adhesive exudation and surface area limitations, while laser welding methods often lead to burrs and equipment cost issues.
Innovation Solution
A laser-welded structure between the housing and cover of flow sensors, with a first welded section surrounding the circuit chamber and a second welded section for reinforcement, featuring a step design with a larger gap between the second target weld portions, and projections or concave portions for enhanced bonding, allowing precise laser radiation to join the components without damaging electronic parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermosetting adhesives are used for sealing the housing and cover, then air-tightness is achieved, but productivity deteriorates due to long curing times
Solution Approach 1:
The patent replaces the chemical bonding mechanism of thermosetting adhesives with a mechanical-thermal bonding mechanism using laser welding. The laser beam melts and fuses the thermoplastic resin housing and cover directly, eliminating the need for adhesive curing time while achieving equivalent or superior sealing reliability.
Solution Approach 2:
The patent changes the material parameter from thermosetting adhesive to thermoplastic resin, which enables laser welding. This parameter change allows the sealing process to transition from a time-consuming chemical curing process to a rapid thermal fusion process, significantly improving productivity while maintaining air-tightness.
2Reliability
If multiple adhesives are used for sealing, then air-tightness is improved, but production cost increases
Solution Approach 1:
The patent merges the sealing function that previously required multiple adhesive applications into a single laser welding process. The laser welding method accomplishes what multiple adhesives attempted to achieve, reducing material costs and simplifying the manufacturing process while maintaining or improving seal quality.
Solution Approach 2:
The patent extracts the sealing function from the adhesive application process and transfers it to the laser welding process. This extraction eliminates the need for multiple adhesive materials and their associated costs, while the laser welding process provides a more reliable and cost-effective sealing solution.
3Reliability
If adhesives are used for sealing, then air-tightness is achieved, but surface area requirements increase due to adhesive exudation
Solution Approach 1:
The patent replaces the adhesive-based sealing system with a laser welding-based sealing system. This substitution eliminates adhesive exudation entirely, as laser welding fuses materials through melting and solidification without requiring excess material to fill gaps, thereby reducing the required surface area for sealing operations.
4Productivity
If laser welding is used to join housing and cover, then productivity is improved, but burrs are generated
Solution Approach 1:
The patent applies local quality control by focusing the laser beam precisely on the weld line between housing and cover. This localized energy application melts only the necessary material at the joint interface, minimizing molten material spillage and burr generation while maintaining high welding speed and productivity.
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 enhances the quality and reliability of flow sensors by preventing leakage, eliminating the need for a press member, and reducing production costs while maintaining air-tightness and improving welding strength.
Implementation Method 1
applying laser radiation from above the cover to the second welded section to make an interval between the second target weld portions welded to each other and then applying laser radiation from above the cover to the first welded section to make an interval between the first target weld portions welded to each other
Data Source
AI summary
A flow sensor includes an auxiliary channel having an opening into which a fluid to be measured is taken; a sensor element that measures the flow of the fluid to be measured; a housing that accommodates electronic parts; and a resin cover. The flow sensor is configured such that junctions of the housing and the cover are formed in locations where first target weld portions, which are formed so that the circuit chamber is surrounded, face each other and second target weld portions, which are disposed for additional reinforcement of the joints, face each other on a bonding face of the housing and a bonding face of the cover with a step being provided. The positioning of the housing and the cover is determined, and the first target weld portions are welded to each other and second target weld portions are welded to each other by way of laser radiation.