Combustion Pressure Sensor Internal Welding Alignment
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Solution Overview
Problem
Pressure sensors with tubular members inserted into a housing often experience axial misalignment due to the number of weld points outside the housing, leading to potential mounting issues when attached to pressure-sensing objects like vehicle engines.
Innovation Solution
The solution involves integrating the first and second tubular members within the housing such that the fixing portion is located inside, reducing axial misalignment by fixing the outer periphery of the second tubular member to the inner periphery of the housing, and using a displacement preventing section to secure the pressure transmission member, thereby minimizing rattling and enhancing fixation strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If multiple weld portions are used to connect tubular members to the housing, then the fixation strength is improved, but the axial misalignment increases
Solution Approach 1:
The patent extracts one of the two weld portions from the external connection to be performed inside the housing. Specifically, the first tubular member is welded to the housing at a first weld portion inside the housing, eliminating the need for an external weld portion. This reduces the number of external connection points that can cause axial misalignment, while maintaining fixation strength through the internal weld structure.
Solution Approach 2:
The patent inverts the conventional welding approach by performing the weld inside the housing rather than outside. The first tubular member extends through the housing with its end inside the housing, allowing the weld to be performed from the interior side. This reversal of the welding location eliminates the need for external weld portions that contribute to axial misalignment.
2Ease of manufacture
If the tubular members extend beyond the housing opening, then the assembly is easier to manufacture, but the axial misalignment increases affecting mountability
Solution Approach 1:
The patent applies local quality by providing a flange at a specific location on the first tubular member (at its intermediate position) that extends beyond the housing opening. This localized structural feature facilitates assembly by providing a mounting interface, while the weld portion inside the housing ensures proper alignment. The flange provides the necessary assembly ease without compromising mountability.
3Ease of manufacture
If the pressure transmission member is loosely fitted in the hollow space, then the assembly is easier to manufacture, but the displacement and rattling increase
Solution Approach 1:
The patent applies preliminary action by providing a fixation structure for the pressure transmission member before final assembly. The hollow space of the first tubular member is designed with a fixation structure that prevents displacement of the pressure transmission member in the radial direction. This preliminary fixation ensures the pressure transmission member remains properly positioned, eliminating rattling and ensuring operational reliability.
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 significantly reduces axial misalignment, ensuring proper mountability and increasing the fixation strength between the tubular members and the housing, while preventing displacement of the pressure transmission member, thus enhancing the sensor's operational reliability.
Implementation Method 1
the first and second tubular members 1, 2 are integrally connected to each other by laser welding at a weld portion K1
Implementation Method 2
The first tubular member 1 and the housing 10 are fixed to each other by laser welding at a weld portion K2
Data Source
AI summary
The pressure sensor includes a first tubular member including at one end portion thereof a sensing section outputting an electrical signal indicative of a pressure applied thereto, and an opening section formed at the other end portion thereof, a second tubular member including an opening section formed at one end portion thereof and a diaphragm located at one end portion thereof, a housing having an opening at one end portion thereof, and a pressure transmission member operating to transmit a pressure applied thereto to the sensing section. The first and second tubular members are integrally connected to each other at their the opening sections. A fixing portion between the first and the second tubular members is located inside the housing, an outer periphery of the second tubular member is fixed to an inner periphery of the opening section of the housing.