On-Wheel Gravity Pump for Tire Pressure Maintenance

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Solution Overview

Problem

Conventional automatic tire pumps face issues with contamination, wear, and inefficiency due to continuous operation and lack of directional independence, leading to suboptimal tire pressure maintenance and potential damage from leaks.

Innovation Solution

A multi-chamber on-wheel air maintenance tire pump system with serially connected pumps and an adjustable pressure control valve, featuring a cam-driven mechanism with low-friction bearings and a filter to prevent contamination, allowing for efficient and directional-independent tire pressure regulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the pump operates continuously to maintain tire pressure, then tire pressure maintenance is improved, but wear and service life are reduced

Engineering Contradiction:
Improvetire pressure maintenanceVSAvoidpump service life
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The pump is designed to operate intermittently rather than continuously, activating only when tire pressure falls below a threshold level. This periodic operation maintains reliable tire pressure while significantly reducing wear and extending pump service life.

Inventive Principle:
Principle #19Periodic action

2Device complexity

If the pump operates at low vehicle speed without an inlet filter, then operational simplicity is improved, but contamination and valve clogging increase

Engineering Contradiction:
Improvepump structureVSAvoidcontaminant ingress
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

An inlet filter is introduced as an intermediary component between the atmosphere and the pump interior. This filter captures contaminants before they can enter and clog the pump valves, protecting the internal mechanisms while maintaining operational simplicity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If the inlet filter is added to prevent contamination, then contaminant ingress is reduced, but filter clogging and pump inoperability increase

Engineering Contradiction:
Improvecontaminant protectionVSAvoidpump operability
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The inlet filter is designed as a disposable or easily replaceable component. When the filter becomes clogged with contaminants, it can be discarded and replaced with a new one, restoring full pump functionality without requiring complex maintenance procedures.

Inventive Principle:
Principle #34Discarding and recovering

4Speed

If the piston and spring are made small to reduce mass, then centrifugal force responsiveness is improved, but friction wear and service life reduction occur

Engineering Contradiction:
Improveresponse speedVSAvoidpump service life
Core Design Contradiction:
SpeedVSDuration of action of stationary object

Solution Approach 1:

The reduced-mass piston and spring assembly operates during periodic pump cycles rather than continuous operation. This intermittent use allows the smaller, more responsive components to achieve adequate service life by accumulating less total wear over time.

Inventive Principle:
Principle #19Periodic action

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 with reduced wear and contamination risk, providing a high compression ratio and efficient pumping capacity while minimizing operational torque and interference with tire mounting/dismounting.

Implementation Method 1

An unbalanced gravity mass and axially uniform cam are used to drive the pumps

Methodology Applied
Scientific EffectGravitation: Gravitation

Implementation Method 2

The air inlet may include a filter to prevent foreign items from being inlet to the pump system

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Implementation Method 3

The pumps may be two-stage pumps with a piston radially movable in a cylinder to draw air from the atmosphere into a primary chamber and pump air from a secondary chamber into the tire cavity

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 4

The piston may be moved outward by centrifugal force resulting from movement of the vehicle and rotation of the wheels

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP3012125B1Air maintenance tire assembly
Publication Date: 2020.12.16 THE GOODYEAR TIRE & RUBBER CO
  • EP3012125B1 patent drawingFigure 1
  • EP3012125B1 patent drawingFigure 2~3
  • EP3012125B1 patent drawingFigure 4

AI summary

A pumping assembly (100) is disclosed for use with a pneumatic tire mounted on a tire rim to keep the pneumatic tire from becoming underinflated. The pumping assembly (100) comprises an even number of pumps (150) attached to a tire rim; a gravity mass (130) for producing a pumping action; a cam (105) fixed to the gravity mass (130) for maintaining the cam (105) in a fixed position relative to the gravity mass (130); and rollers (160) for engaging the cam (105) and producing the pumping action as the tire rim rotates and the gravity mass (130) retards rotation of the cam (105) as the tire rim rotates.