Air Maintenance Tire Valve Stem with Peristaltic Pumping
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Solution Overview
Problem
Tires naturally lose air pressure over time, leading to underinflation, which affects fuel economy, tire life, and vehicle performance, and existing Tire Pressure Monitoring Systems require driver intervention for re-inflation.
Innovation Solution
An air maintenance tire assembly with a peristaltic pumping system using soft tubing and compression fittings to maintain tire pressure, featuring a valve housing with a relief valve and check valve to automatically adjust air flow, ensuring the tire remains at a preset pressure without driver intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a Tire Pressure Monitoring System is used to warn drivers of low tire pressure, then drivers can be alerted to maintain proper pressure, but driver intervention is still required for re-inflation which reduces convenience
Solution Approach 1:
The system incorporates an automatic air maintenance feature that self-regulates tire pressure without driver intervention. The valve housing with pressure-sensitive diaphragm automatically opens to admit air when pressure drops and closes when pressure reaches the preset level, enabling the tire to maintain itself autonomously.
Solution Approach 2:
The system uses a pressure-sensitive diaphragm that responds to tire pressure changes and automatically controls the valve operation. When pressure drops below the preset level, the diaphragm moves to open the valve; when pressure reaches the preset level, the diaphragm moves to close the valve, creating a closed-loop feedback control system.
2Strength
If compression fittings are used to connect air pumping means to valve housing, then secure connection is achieved, but dynamic loading causes stress and potential failure
Solution Approach 1:
The system incorporates flexible hoses between the compression fittings to absorb and cushion the dynamic loading stresses generated during tire rotation. This flexible element protects the rigid compression fitting connection from stress concentration and potential failure under cyclic loading conditions.
Solution Approach 2:
The system uses flexible hoses to connect the air pumping means to the valve housing, allowing these thin-walled flexible elements to accommodate and dissipate dynamic stresses from tire rotation, preventing stress concentration at the rigid compression fitting connections.
3Reliability
If air pumping means is continuously operated to maintain tire pressure, then tire pressure is maintained at preset level, but energy is consumed continuously
Solution Approach 1:
The air pumping operation occurs periodically rather than continuously. The pressure-sensitive diaphragm automatically activates the air pump only when tire pressure drops below the preset level, and the pump operates only during the brief period needed to restore pressure, minimizing energy consumption while maintaining reliable pressure levels.
Solution Approach 2:
The pressure-sensitive diaphragm creates a feedback control system that activates air pumping only when needed (when pressure drops below preset level) and stops when pressure is restored, eliminating continuous operation and reducing energy consumption to only the minimum necessary periods.
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 system effectively maintains tire pressure by using a peristaltic pumping mechanism that automatically adjusts air flow, reducing the need for driver intervention and enhancing fuel efficiency, tire longevity, and vehicle handling.
Implementation Method 1
air pumping means for generating pressurized air for maintaining air pressure within the tire cavity at a preset pressure level, the air pumping means including a soft tubing and compression fittings
Implementation Method 2
the valve housing further includes a relief valve that opens and closes to place the air pumping means in 'open' and 'closed' conditions
Implementation Method 3
a check valve in the valve stem selectively opens and closing an air passage from the valve stem passageway into the tire cavity
Data Source
AI summary
An air maintenance tire assembly includes a tire having a tire cavity bounded by first and second sidewalls extending to a tire tread region, air pumping means for generating pressurized air for maintaining air pressure within the tire cavity at a preset pressure level, the air pumping means including a soft tubing and compression fittings for mitigating dynamic loading on the compression fittings, and a valve housing disposed adjacent an outward end of the valve stem and operative to selectively open and close pressurized air flow from the valve stem internal passageway into the tire cavity. The valve housing is connected to the air pumping means by the soft tubing and compression fittings for mitigating dynamic loading on the compression fittings.