Pneumatic Tire Tread Sipes With Widened Bottoms for Wear-Stage Drainage

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Solution Overview

Problem

Existing pneumatic tire designs face decreased drainage performance and pattern noise issues due to wear, as groove volume diminishes and widthwise sipes can contribute to noise.

Innovation Solution

A pneumatic tire design featuring circumferential main grooves, widthwise grooves, and widthwise sipes with a widened portion that inclines at specific angles to maintain drainage efficiency and reduce noise, where the sipes' width increases at the bottom and extend along the tire width direction to connect with circumferential main grooves.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If widthwise grooves are provided in the widthwise outermost land portion to improve drainage performance, then drainage performance is improved, but groove volume decreases when wear progresses

Engineering Contradiction:
Improvedrainage performanceVSAvoidgroove volume
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The widthwise sipe is designed with a widened portion located deeper in the tread than the opening portion, creating different functional zones within the same sipe structure. The opening portion maintains a smaller width to reduce pattern noise at the surface level, while the widened portion located deeper provides enhanced water evacuation capacity. This local differentiation allows the sipe to simultaneously achieve noise suppression and effective drainage throughout the tire's service life.

Inventive Principle:
Principle #3Local quality

2Reliability

If widthwise sipes are provided in the widthwise outermost land portion to remove water film and improve drainage performance, then drainage performance is improved, but pattern noise increases

Engineering Contradiction:
Improvedrainage performanceVSAvoidpattern noise
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The widthwise sipe is designed with a widened portion located deeper in the tread than the opening portion, creating different functional zones within the same sipe structure. The opening portion maintains a smaller width to reduce pattern noise at the surface level, while the widened portion located deeper provides enhanced water evacuation capacity. This local differentiation allows the sipe to simultaneously achieve noise suppression and effective drainage throughout the tire's service life.

Inventive Principle:
Principle #3Local quality

3Reliability

If groove volume is maintained to improve drainage performance when wear progresses, then drainage performance is maintained, but widthwise sipes become a source of pattern noise

Engineering Contradiction:
Improvedrainage performanceVSAvoidpattern noise
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The widthwise sipe is designed with a widened portion located deeper in the tread than the opening portion, creating different functional zones within the same sipe structure. The opening portion maintains a smaller width to reduce pattern noise at the surface level, while the widened portion located deeper provides enhanced water evacuation capacity. This local differentiation allows the sipe to simultaneously achieve noise suppression and effective drainage throughout the tire's service life.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4046826B1Pneumatic tire
Publication Date: 2024.06.05 BRIDGESTONE CORP
  • EP4046826B1 patent drawingFigure 1
  • EP4046826B1 patent drawingFigure 2
  • EP4046826B1 patent drawingFigure 3A~3B

AI summary

A pneumatic tire includes circumferential main grooves extending in the tire circumferential direction on the tread surface, and in widthwise outermost land portions, widthwise grooves extending from the tread edges inward in the tire width direction and widthwise sipes extending from the tire widthwise inner edge of the widthwise grooves inward in the tire width direction and connecting to the circumferential main groove. Each widthwise sipe includes a widened portion, by the sipe bottom, with a larger sipe width than at the tread surface. A rectangle ratio is less than 0.8. In a tire radial region containing the widened portion, the widened portion includes a portion extending at a first angle relative to the tire width direction. In plan view of the tread surface, each widthwise sipe extends along the tire width direction or at a second angle smaller than the first angle relative to the tire width direction.