Tire-Wheel Assembly Groove Layout for Wireless Power Reception
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Solution Overview
Problem
Current tire and wheel assemblies using the electromagnetic induction method for power reception face inefficiencies in power transfer due to interference from tread rubber and other components, limiting the effectiveness of automatic power feeding in electric vehicles.
Innovation Solution
A tire and wheel assembly design featuring a tire with reinforcement layers and a power reception coil, where circumferential main grooves are optimized in depth and width to minimize interference with the magnetic flux, and the reinforcement layers' cord ends are positioned inward from the shoulder region to enhance durability and power reception efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the tread rubber is made thicker to improve durability, then the tire strength is improved, but the power reception efficiency deteriorates due to increased magnetic flux interference
Solution Approach 1:
The tire structure is segmented into distinct functional zones: the tread portion with circumferential grooves for power reception, and the reinforcement layers (belt layers) positioned strategically to provide structural strength. This segmentation allows the tread rubber to be optimized for magnetic flux transmission while reinforcement layers handle mechanical strength requirements.
Solution Approach 2:
Different regions of the tire are given different properties: the tread portion has optimized rubber thickness and groove depth for electromagnetic permeability, while the reinforcement layers are positioned at specific locations (with cord ends inward from shoulder regions) to provide localized strength where needed without interfering with power reception in the tread area.
2Reliability
If the circumferential main groove depth is increased to improve power reception efficiency, then the magnetic flux transmission is improved, but the tire strength deteriorates
Solution Approach 1:
The groove depth is optimized to a specific parameter range (0.5mm to 4.5mm from the groove bottom to the outermost reinforcement member) that balances two competing requirements: sufficient depth to allow magnetic flux transmission for power reception, while maintaining adequate rubber thickness to preserve tire structural strength.
3Strength
If the reinforcement layers are extended to the shoulder region to improve tire durability, then the tire strength is improved, but the power reception efficiency deteriorates due to increased interference with magnetic flux
Solution Approach 1:
The reinforcement layers are strategically positioned with their cord ends located inward from the shoulder regions, creating a local quality distribution where the tread portion maintains electromagnetic permeability for power reception while the reinforcement layers provide strength in the central and lateral areas without extending into the shoulder regions where they would interfere with magnetic flux.
4Reliability
If the groove depth is increased beyond optimal levels to improve power reception, then the magnetic flux transmission is improved, but the tire durability deteriorates
Solution Approach 1:
The groove depth parameter is optimized to a specific range (0.5mm to 4.5mm to the outermost reinforcement member) that balances power reception efficiency with tire durability. Excessive groove depth would compromise structural integrity, while insufficient depth would hinder magnetic flux transmission. The optimal parameter range ensures both functions are satisfied.
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 optimized design achieves higher power reception efficiency and improved durability by reducing magnetic flux interference and protecting the reinforcement layers from strain, ensuring effective automatic power feeding and extended tire life.
Implementation Method 1
Current is caused to flow through a power transmission coil (primary coil) installed on the road surface side to generate magnetic flux in, for example, a direction perpendicular to the road surface. As a result of this magnetic flux passing through a power reception coil (secondary coil) on the vehicle side, current flows through the power reception coil, thus supplying electric energy from the power transmission coil to the power reception coil.
Data Source
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AI summary
A tire and wheel assembly comprises: a tire including a tread portion; a wheel including a rim portion on which the tire is mounted; and a power reception coil, wherein one or more circumferential main grooves extend in a tire circumferential direction on a tread surface of the tread portion, and at least one circumferential main groove satisfies OTD ≥ SBG in a reference state.