Sensor Support Portion Geometry for Flow Measurement Alignment
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Solution Overview
Problem
Flow sensors in physical quantity measurement devices face accuracy issues due to potential deviations in the posture of the sensor assembly, which can lead to decreased measurement accuracy of fluid flow rates, as the relative posture of the sensor assembly with respect to the sensor body may deviate during manufacturing, affecting the position and alignment of the sensor chip in the bypass flow path.
Innovation Solution
The physical quantity measurement device is designed with a sensor support portion that includes a support tip end and a front fixed portion, where the separation distance between the front fixed base end and the exposed base end is smaller than the separation distance between the exposed base end and the support tip end, minimizing the radius of rotation and reducing misalignment of the physical quantity sensor, thus enhancing measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensor assembly is positioned in the bypass flow path, then the flow rate can be measured, but the measurement accuracy decreases due to potential deviations in the posture of the sensor assembly
Solution Approach 1:
The sensor support portion is divided into two functional segments: a front fixed portion for mounting to the housing and a support tip end portion for holding the sensor chip. This segmentation allows independent optimization of each part's function and reduces the cumulative error in sensor positioning.
Solution Approach 2:
The patent introduces a specific geometric dimensioning approach by defining the support front surface and establishing dimensional relationships between the front fixed portion, support tip end portion, and sensor chip. This dimensional control in the height direction ensures the sensor chip maintains proper orientation and position in the bypass flow path regardless of manufacturing variations.
2Measurement precision
If the sensor chip is exposed from the support front surface, then the sensor can detect the fluid flow, but misalignment occurs due to deviation in the relative posture of the sensor assembly
Solution Approach 1:
The sensor support portion is pre-configured with a specific geometric structure during manufacturing, including the support front surface and the dimensional relationship between the front fixed portion and support tip end portion. This preliminary structural preparation ensures that when the sensor chip is mounted, it automatically achieves the correct alignment and orientation in the bypass flow path, compensating for potential manufacturing variations.
3Length of moving object
If the support tip end portion is separated from the front fixed portion, then the sensor can be positioned in the flow path, but the radius of rotation increases leading to greater misalignment
Solution Approach 1:
The patent optimizes the geometric parameters of the sensor support portion, specifically the dimensional relationship between the front fixed portion and support tip end portion in the height direction. By carefully controlling these parameters, the design achieves the necessary positioning capability while minimizing the radius of rotation and reducing misalignment of the sensor chip in the bypass flow path.
Data Source
AI summary
A sensor support portion supports a physical quantity sensor. A flow path housing portion forms a measurement flow path, which accommodates a support tip end portion of the sensor support portion. The sensor support portion includes a support front surface, which includes a front fixed portion away from the support tip end portion and fixed to an inner surface of the flow path housing portion. The physical quantity sensor includes a sensor exposure surface exposed from the support front surface. A separation distance between an end portion of the front fixed portion and an end portion of the sensor exposure surface is smaller than a separation distance between the end portion of the sensor exposure surface and the support tip end portion.