Pressure Sensor Pinching Member Welding for CO2 Durability
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Solution Overview
Problem
Pressure sensors used for detecting high-pressure refrigerants, such as CO2, are prone to crackage and breakage due to repeated high-pressure applications at the weld portion, leading to potential failure.
Innovation Solution
A pressure sensor design featuring a pinching member bonded by welding, which applies a load to press the base and receiving member together, preventing them from moving apart under high pressure, and utilizing a diaphragm and sealed liquid to transmit pressure, enhancing durability and preventing weld crackage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the pressure sensor uses a weld portion to connect the lid member to the pressure detection element, then the structure is simple and easy to manufacture, but the weld portion cracks and breaks under repeated high-pressure applications
Solution Approach 1:
The patent introduces a pinching member as an intermediary component between the lid member and the pressure detection element. This pinching member mechanically clamps the components together, replacing the direct weld connection that was prone to cracking. The pinching member distributes the clamping force across multiple contact points, preventing stress concentration and crack propagation at the weld portion while maintaining assembly simplicity.
Solution Approach 2:
The pinching member is designed with a resilient or elastic property that allows it to dynamically adapt to pressure variations. Under repeated high-pressure applications, the pinching member can elastically deform to accommodate pressure changes while maintaining continuous contact and clamping force, preventing the lid member from disengaging or cracking under cyclic loading conditions.
2Reliability
If the lid member is formed in an L-shaped form to reduce rotating force around the weld portion, then the weld portion durability is improved, but the structural complexity increases
Solution Approach 1:
Instead of modifying the lid member's geometry to an L-shaped form, the patent uses a pinching member as a mediator to provide the necessary mechanical constraint. The pinching member applies clamping force directly to the lid member and pressure detection element, eliminating the need for complex L-shaped geometry while achieving the same goal of preventing rotational movement and weld portion cracking.
Solution Approach 2:
The patent separates the functions of pressure containment and mechanical constraint into different components. The lid member maintains its simple pressure-containing geometry, while the pinching member independently provides the constraint function. This segmentation allows each component to be optimized for its specific function without requiring complex integrated geometry.
3Reliability
If the pinching member is welded to the base and receiving member under load, then the durability against repeated pressure is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The pinching member is pre-loaded onto the base and receiving member before the welding process. This preliminary positioning ensures that the weld portion is formed under the correct load condition, creating a pre-compressed joint that is optimized for durability. The pre-loading action establishes the proper clamping force and alignment before the permanent weld connection is made, ensuring the joint can withstand repeated pressure cycles.
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 design effectively prevents pressure sensor breakage under high-pressure conditions by improving durability through the pinching member's welding state and elastic force application, ensuring the sensor remains functional even with repeated high-pressure exposure.
Implementation Method 1
transmitting a pressure applied to a pressure detection chamber from an external portion via the liquid
Implementation Method 2
a pinching member which pinches the base and the receiving member in a state of pinching the diaphragm in such a manner as to prevent both of the base and the receiving member from moving away from each other
Data Source
Figure 1A
Figure 1B
AI summary
The invention provides a safety pressure sensor which can prevent the pressure sensor from being broken due to a high pressure even in the case that the pressure sensor is used for detecting the pressure of the flow path through which the high pressure refrigerant such as CO2 passes. In a pressure sensor (1) provided with a pressure detection element (2), a base (4) in which the pressure detection element is fixed to an inner surface, a receiving member (5) which is arranged so as to face to the base, a diaphragm (6) which is pinched by the base and the receiving member, a pinching member (22) which pinches the base and the receiving member in a state of pinching the diaphragm in such a manner as to prevent both of the base and the receiving member from moving away from each other, the pinching member being bonded by welding to any one thereof in a state in which a load is applied in a direction in which both are pressed from each other, and a liquid which is sealed in a space between the base and the diaphragm, the pressure in the space between the receiving member and the diaphragm is transmitted to the pressure detection element via the diaphragm and the liquid.