Laser-Welded Sensor Housing With Stepped Peripheral Edge
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Solution Overview
Problem
The existing assembly structure for photoelectric sensors, which relies on precise management of body case and body cover parts and large laser beam spot diameters for welding, leads to increased production costs and potential thermal damage to internal components.
Innovation Solution
A sensor device design where the body cover is fixed to the body case using laser-welding at a portion distant from the end surface, with a step at the peripheral edge and a polygonal shape to facilitate easy positioning and reduce thermal effects, allowing for a smaller laser beam spot diameter and reduced production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the laser beam's spot diameter is made large to accommodate precision variations in body case and body cover, then the bonding reliability is improved, but the equipment cost increases and thermal damage to internal components occurs
Solution Approach 1:
The patent applies local quality by creating a stepped structure at the peripheral edge of the body case, where only the localized step region undergoes laser welding while the rest of the casing remains unaffected. This localized approach allows precise control of the laser beam spot diameter at the welding location, ensuring reliable bonding without subjecting the entire casing and internal components to high temperatures.
Solution Approach 2:
The patent segments the body case structure by adding a step portion that separates the welding zone from the internal component area. This segmentation allows the laser beam to be concentrated on the step peripheral edge, achieving reliable bonding at the joint while isolating internal components from thermal effects.
2Ease of manufacture
If the laser beam's spot diameter is made large to accommodate precision variations, then the ease of manufacture is improved, but the production cost increases due to larger equipment requirements
Solution Approach 1:
The stepped structure creates a localized welding zone with defined geometry, allowing the use of smaller, more cost-effective laser equipment. The step portion provides a precise target area for the laser beam, eliminating the need for large spot diameters and expensive high-power laser systems while maintaining tolerance to part precision variations.
3Strength
If the laser beam irradiation power is increased to ensure external melting of metallic material, then the bonding strength is improved, but the temperature increase of the casing becomes significant causing negative effects on assembled components
Solution Approach 1:
The patent concentrates laser irradiation power locally at the step peripheral edge where the welding is needed. The stepped structure acts as a heat sink and barrier, confining the high-temperature zone to the welding location only. This allows high power density for strong bonding without significant temperature increase in the overall casing, protecting resin and rubber components from thermal damage.
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 configuration reduces production costs and ensures reliable bonding of the body case and body cover while minimizing thermal impact on internal components, enhancing the aesthetic appearance and operational efficiency.
Implementation Method 1
the body cover is fixed to the body case by providing a welded portion surrounding the opening using laser-welding at a portion distant from an end surface of the body cover in a boundary of the overlapping region
Implementation Method 2
the end surface of the body cover and the end surface of the above step of the body case opposite thereto mutually melt together so that an externally molten metallic material fills a gap between these end surfaces and furthermore, the material is cooled and thus solidified to form a welded portion
Data Source
AI summary
A sensor device includes a body case provided with an opening, and a body cover assembled to the body case to cover the opening. The body cover has at an outer peripheral portion thereof an overlapping region overlapping a portion of the body case located at a peripheral edge of the opening. The body cover is fixed to the body case by providing a welded portion surrounding the opening using laser-welding at a portion distant from an end surface of the body cover in a boundary of the overlapping region of the body cover and a portion of the body case overlapping the overlapping region.