Sensor Valve Assembly Sealing Structure for High-Pressure Leakage Isolation
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Solution Overview
Problem
Existing sensor devices face challenges in maintaining tightness under high pressure environments, particularly in automotive air conditioning systems, where refrigerant pressures can reach 500 Psi, leading to potential leakage and damage to internal circuit components.
Innovation Solution
The sensor device incorporates a sleeve with a cylinder wall hermetically connected to the circuit substrate, sealed by a fitting portion, and uses welding or bonding connections to enhance sealing, ensuring the inner cavity is not in communication with the fluid channel, thereby preventing leakage and improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a sealing ring is used in a groove to seal the ceramic base, then the device can be assembled, but the sealing performance deteriorates under high pressure conditions
Solution Approach 1:
The invention extracts the sealing ring from the high-pressure fluid path by positioning it in a groove on the outer periphery of the ceramic base, away from the through-hole and internal cavities. This removes the sealing ring from the critical sealing zone where high pressure would cause failure, while still allowing it to perform its sealing function for the external interface.
Solution Approach 2:
The invention introduces a sealing structure formed by the shell and the ceramic base itself as an intermediary barrier between the internal cavities and the external environment. This intermediary sealing structure does not rely on the sealing ring for high-pressure containment, allowing the sealing ring to be positioned in a non-critical location.
2Reliability
If the inner cavity is separated from the channel, then the circuit substrate is protected from fluid leakage, but the device complexity increases
Solution Approach 1:
The invention segments the device into distinct functional zones: an inner cavity housing the circuit substrate isolated from fluid, and an outer fluid handling section with the through-hole and channel. The ceramic base acts as a separator between these zones, allowing the circuit substrate to be protected without requiring complex additional components.
Solution Approach 2:
The invention employs a nested structure where the inner cavity with the circuit substrate is positioned within the overall device housing, surrounded by the ceramic base and shell. The circuit substrate and its cavity are nested within the protective envelope formed by the ceramic base and shell, providing inherent protection without additional complex sealing mechanisms.
3Reliability
If the sealing ring is positioned to seal the through-hole, then fluid leakage is prevented, but the sealing ring suffers from fatigue failure under high pressure
Solution Approach 1:
The invention extracts the sealing ring from the high-pressure sealing function by positioning it in a groove on the outer periphery of the ceramic base, away from the through-hole. The shell and ceramic base structure itself provides the sealing for the through-hole, removing the sealing ring from the high-stress environment that caused fatigue failure.
Solution Approach 2:
The invention creates a redundant sealing system where the shell-ceramic base interface provides the primary sealing function for the through-hole, duplicating the sealing role previously performed solely by the sealing ring. This allows the sealing ring to be relocated to a non-critical position, eliminating its exposure to high-pressure fatigue.
Data Source
AI summary
A sensor device includes a housing, a circuit substrate, a sensing element, and a sleeve. The sensor device further includes an inner cavity and a channel located on different sides of the circuit substrate, respectively. The sleeve has a cylinder wall located on a periphery of the channel. A tail end of the cylinder wall in an axial direction of the channel is sealably connected to the circuit substrate. The housing is provided with a matching part including an accommodation part and a first peripheral wall part forming the accommodation part. The sleeve is at least partially accommodated in the accommodation part. The first peripheral wall part is sealably connected to the cylinder wall. The inner cavity is not communicated with the channel. The sealing performance between the inner cavity of the sensor device and the channel is good. Also provided is a valve assembly having the sensor device.