Flanged Dome Pressure Switch Hysteresis Reduction
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Solution Overview
Problem
Existing pressure switches often suffer from hysteresis issues due to the snap action of dome switches, leading to inefficiencies and reduced operational cycles, and are either complex and costly or simple and less reliable.
Innovation Solution
A pressure switch design featuring a flanged dome with a preload force anchored to a substrate, ensuring an airtight seal and elastic movement, reducing hysteresis and increasing operational cycles, while being cost-effective and compact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dome switch is used in a pressure switch, then the device can detect pressure changes, but hysteresis occurs due to snap action reducing operational cycles
Solution Approach 1:
The patent changes the physical parameters of the dome by adding a flange and anchoring it to the substrate. This constraint modifies the dome's deformation characteristics, preventing snap action and eliminating hysteresis while maintaining pressure detection capability. The anchored flange ensures the dome deforms in a controlled manner throughout its operational cycles.
2Reliability
If a flange is added to the dome and anchored to the substrate, then hysteresis is eliminated and elastic movement is achieved, but the device complexity increases
Solution Approach 1:
The flange is integrated directly into the dome structure, merging the sealing function and the constraint function into a single component. This eliminates the need for separate sealing elements or constraint mechanisms, reducing overall device complexity while achieving the desired elastic movement and hysteresis reduction.
Solution Approach 2:
The flange serves multiple functions simultaneously: it provides an airtight seal between the dome and substrate, anchors the dome to prevent lateral movement, and constrains the dome to deform only in the vertical direction. This multi-functionality reduces the need for additional components.
3Reliability
If the dome is preloaded against the contact pad, then electrical connection is established, but the force required to actuate the switch increases
Solution Approach 1:
The contact pad is designed with a specific shape that matches the dome's contact surface, concentrating the preload force on a small area. This localized contact ensures reliable electrical connection while minimizing the total force required for actuation, as the force is efficiently transmitted through the optimized contact interface.
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 achieves reliable, low-hysteresis operation with increased durability and operational cycles, making it suitable for applications like tire pressure monitoring, with adjustable threshold settings and integration into printed circuit boards for manufacturing efficiency.
Implementation Method 1
causes the dome to move substantially elastically during deflection of the dome
Implementation Method 2
allows a pressurized medium on the second side of the substrate to flow through the substrate to the first side of the substrate which causes the dome to depress
Data Source
AI summary
Disclosed is a pressure switch that utilizes a dome switch having a flange surrounding the dome. The flange is anchored to a substrate such that the dome portion is in contact with a contact pad on the substrate. A pressure medium applied through passageways in the substrate flexes the dome in an elastic manner so that the dome does not contact the contact pad. When the pressure medium falls below a predetermined threshold level, the dome expands and contacts the contact pad to complete a circuit that indicates that the pressure of the pressure medium has fallen below the threshold level. Preloading force can be created between the dome and the contact pad to ensure a solid electrical connection. The preloading force can also be adjusted.