Laser-Welded Flow Sensor Housing With Burr-Controlling Protrusions
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Solution Overview
Problem
Conventional flow sensors face challenges in achieving high precision and reliability due to the use of thermally curable adhesives, which require extended curing times, increase production costs, and limit design latitude, while laser welding methods struggle with burr control and air-tightness in the bonding process.
Innovation Solution
A laser welding structure and method are employed for the flow sensor, where protrusions on the housing and cover are designed to control burr formation, ensuring enhanced bonding reliability and precision by aligning the protrusions to prevent burrs from protruding into the auxiliary channel, thereby stabilizing flow rate measurement precision and reducing production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermally curable adhesives are used to seal the housing and cover, then sealing reliability is improved, but productivity deteriorates due to curing time exceeding ten minutes and production cost increases
Solution Approach 1:
The patent replaces the chemical bonding mechanism of thermally curable adhesives with a mechanical bonding mechanism using laser welding. The housing and cover are bonded through direct laser welding without adhesives, eliminating the curing time constraint while maintaining sealing reliability. This substitution of bonding mechanism resolves the contradiction between reliability and productivity.
2Reliability
If thermally curable adhesives are used for sealing, then sealing reliability is improved, but production cost becomes bulky due to large adhesive consumption
Solution Approach 1:
The patent eliminates adhesive consumption entirely by replacing chemical bonding with laser welding. The housing and cover are bonded through direct fusion without any adhesive material, thereby resolving the contradiction between sealing reliability and adhesive consumption.
3Productivity
If laser welding is used to bond housing and cover, then productivity is improved and adhesive consumption is reduced, but burrs are generated during welding
Solution Approach 1:
The patent extracts and removes the harmful burrs generated during laser welding through a dedicated burr removal step. After laser welding bonds the housing and cover, the protruding burrs are removed to prevent interference with the auxiliary channel, thereby resolving the contradiction between productivity improvement and burr generation.
4Object-generated harmful factors
If a closure space is provided to receive burrs during laser welding, then burr control is improved, but design latitude is limited due to extra space requirement
Solution Approach 1:
Instead of providing a closure space to contain burrs, the patent extracts and removes the burrs through a burr removal step. This approach controls burrs without requiring additional design space, thereby resolving the contradiction between burr control and design latitude.
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 enhances the reliability and stability of flow rate measurement precision, reduces production costs, and improves the bonding process by controlling burr formation, resulting in a more efficient and precise flow sensor.
Implementation Method 1
a laser beam is irradiated onto a flow sensor, thereby welding the bonding section (331) of the cover (303, 304) to the protrusion section (307) of the housing (302)
Data Source
AI summary
Provided are a laser-welded structure and a laser welding method for a cover and a housing ensuring high reliability and suppressing changes in characteristics due to burrs protruding into a subpassage of the flow sensor. To this end, this flow sensor is provided with a housing, a cover, a circuit chamber sealed between these and housing electronic components or wiring, and a subpassage through which the fluid flows that is to be sensed, and is characterized in that there are projections provided on both ends of the joining section of the cover where the housing and the cover are laser-welded, and the height of the projection on the subpassage side is greater than the height of the projection on the side opposite of the subpassage.