Physical Quantity Detection Device Adhesive Segmentation
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Solution Overview
Problem
Physical quantity detection devices for internal combustion engines face challenges in achieving both high rigidity and sealability, as reducing device thickness to minimize pressure loss leads to decreased rigidity and potential deformation during vibration, and the use of epoxy adhesives compromises sealability.
Innovation Solution
A physical quantity detection device design featuring a housing with a first adhesive groove for improved rigidity and a second adhesive groove for enhanced sealability, using adhesives with specific properties such as high Young's modulus and thixotropy, respectively, to maintain structural integrity and prevent fluid leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the thickness of the device body is reduced to minimize pressure loss in the intake passage, then pressure loss decreases, but the rigidity of the main body portion decreases and detection accuracy may be affected
Solution Approach 1:
The bonding structure is segmented into two distinct adhesive grooves: a first adhesive groove for structural bonding and a second adhesive groove for sealing. This segmentation allows each adhesive to perform its specialized function independently, resolving the contradiction between rigidity and sealability
Solution Approach 2:
Different adhesive properties are applied to different locations: high Young's modulus adhesive is used in the first adhesive groove where structural rigidity is needed, while high thixotropy adhesive is used in the second adhesive groove where sealability is critical. This local differentiation resolves the contradiction by optimizing each location for its specific requirement
2Strength
If epoxy adhesive is used to improve the rigidity of the main body portion, then rigidity increases, but sealability decreases due to low viscosity
Solution Approach 1:
The bonding system is divided into two separate adhesive grooves, each dedicated to a specific function: the first groove uses epoxy adhesive for rigidity, while the second groove uses a different adhesive for sealing. This eliminates the need to compromise either property in a single adhesive selection
Solution Approach 2:
The patent applies different adhesive materials with different properties to different locations based on functional requirements. The first adhesive groove receives adhesive optimized for structural strength, while the second adhesive groove receives adhesive optimized for sealing, resolving the contradiction between rigidity and sealability
3Strength
If the inner wall surface of the flange and the outer peripheral wall surface of the cover are bonded by epoxy adhesive, then rigidity should improve, but the amount of decrease in the cross-sectional coefficient at the bonded portion increases, rigidity decreases, deformation increases during vibration, and stress may concentrate on the root of the base body
Solution Approach 1:
The bonding interface is segmented into two distinct adhesive grooves positioned at different locations. This segmentation allows the first adhesive to provide structural bonding while the second adhesive provides sealing, preventing the cross-sectional coefficient decrease that would occur with a single adhesive layer and reducing stress concentration
Solution Approach 2:
Different adhesive properties are applied at different locations: the first adhesive groove is optimized for structural integrity and rigidity, while the second adhesive groove is optimized for sealing and preventing stress concentration. This local optimization prevents deformation during vibration
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 both the rigidity and sealability of the device, reducing deformation and pressure loss while maintaining accurate flow rate detection, thus improving the overall performance and reliability of the internal combustion engine's intake air measurement.
Implementation Method 1
The first adhesive has a Young's modulus higher than that of the second adhesive
Implementation Method 2
the second adhesive has a thixotropy higher than that of the first adhesive
Data Source
AI summary
Provided is a physical quantity detection device capable of achieving both rigidity improvement and sealability improvement. A physical quantity detection device (20) of the invention includes a housing (100), a cover (200), a chip package (310), and a flow rate sensor (311) supported by the chip package and arranged in a sub-passage. The housing includes: a first adhesive groove 160A which is an adhesive groove to which an adhesive for bonding the cover is applied, extends along a proximal end of the housing, extends in the protruding direction of the housing from the proximal end of the housing to a position on a more distal end side of the housing than the chip package, and is applied with the first adhesive 401; and a second adhesive groove 160B which extends along the sub-passage 134 and is applied with the second adhesive 402. The first adhesive has a higher Young's modulus, and the second adhesive has a higher thixotropy.