TPMS Valve Stem Latching Mechanism for Tilting Moment Reduction
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Solution Overview
Problem
Existing tire pressure monitoring systems face challenges in mounting the unit on tire valves without causing excessive tilting moments, which can damage rubber seals at high speeds, and require a balance between mechanical load capacity and cost-effectiveness.
Innovation Solution
A tire pressure monitoring system with a plastic housing and integrally formed latching element that engages with multiple latching recesses on the valve stem, allowing for easy installation and low tilting moments by positioning the unit close to the rim through-bore, and a lever arm mechanism for tool-free attachment and detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tire pressure monitoring unit is mounted on the valve stem, then the monitoring function is achieved, but tilting moments occur at high speeds that can damage the rubber seal
Solution Approach 1:
A counterweight element is integrated into the valve assembly, positioned to generate a counterbalancing moment that offsets the tilting moment produced by the tire pressure monitoring unit. This counterweight creates an opposing rotational force that neutralizes the harmful tilting effect on the rubber seal during high-speed operation.
Solution Approach 2:
The solution moves from simply reducing mass to adjusting the spatial distribution of mass along the valve stem axis. By positioning the counterweight at a specific distance from the rim flange and the monitoring unit at another position, the system balances moments in the rotational dimension, transforming an unbalanced single-point mass problem into a distributed mass balance solution.
2Force
If the mass of the tire pressure monitoring unit is reduced, then tilting moments are reduced, but mechanical load capacity may be compromised
Solution Approach 1:
Instead of merely reducing the monitoring unit mass, a counterweight is added to balance the moment. This allows the monitoring unit to maintain its necessary structural integrity and sensor components while the counterweight compensates for the tilting effect, preserving mechanical load capacity without sacrificing balance.
Solution Approach 2:
The valve assembly incorporates multiple materials with different density and strength characteristics. The counterweight element and monitoring unit are designed using material selection that optimizes both mass distribution for moment balance and structural properties for mechanical strength, creating a composite structure that satisfies both requirements.
3Force
If the tire pressure monitoring unit is positioned closer to the rim through-bore, then tilting moments are reduced, but installation complexity increases
Solution Approach 1:
The valve assembly is segmented into distinct functional elements: the monitoring unit, the counterweight, and the latching mechanism. This segmentation allows each component to be independently positioned and adjusted, simplifying the installation process by enabling modular assembly rather than requiring complex integrated positioning.
Solution Approach 2:
The latching mechanism is designed to automatically engage and secure the monitoring unit and counterweight in their correct positions on the valve stem. This self-latching feature eliminates the need for complex alignment procedures or specialized installation tools, allowing the system to self-configure during installation while maintaining optimal positioning for minimal tilting moments.
Data Source
AI summary
A tire pressure monitoring system with a tire valve and a tire pressure monitoring unit includes a plastic housing, in which a pressure sensor for measuring the tire pressure and a transmitter for wirelessly transmitting tire pressure data are arranged. The tire pressure monitoring unit is attached to a stem of the tire valve and the stem comprises latching recesses, into which a latching element of the tire pressure monitoring unit engages. The latching element is realized integrally with a wall of the housing. A method for installing a tire pressure monitoring system on a rim is furthermore proposed.