Pneumatic Tire Sealant Layer Layout for Uniform Thickness
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Solution Overview
Problem
The conventional method of coating sealant material in a spiral shape on the inner surface of a tire leads to a large overlap area, resulting in variations in thickness and reduced adhesiveness of the sound absorbing layer to the sealant layer, causing defects and decreased performance.
Innovation Solution
A method of step pasting the sealant material in a tire, aligning circling parts parallel to the tire-circumferential direction, reducing the overlap area and ensuring the sound absorbing layer adheres effectively to the sealant layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sealant material is coated in a spiral shape along the tire inner surface, then the sealant layer provides puncture prevention function, but the overlap area at both ends in the tire-width direction increases, causing variation in thickness and decline in adhesiveness of the sound absorbing layer
Solution Approach 1:
The sealant layer is divided into multiple independent strip-shaped windings arranged in parallel along the tire circumferential direction, rather than being coated as a continuous spiral. Each strip is applied separately with minimal overlap, segmenting the coating process to eliminate the large overlap accumulation that occurs in spiral coating methods.
Solution Approach 2:
The coating method transitions from a spiral pattern (combining circumferential and width-directional movement) to parallel strip windings aligned primarily in the circumferential direction. This dimensional reorganization of the coating pattern reduces the overlap area at the width-directional ends by eliminating the spiral's inherent overlap accumulation.
2Ease of manufacture
If sealant material is coated in a spiral shape, then the sealant layer is formed continuously, but the large overlap area at initial and final circling portions causes defects and reduced adhesiveness
Solution Approach 1:
The continuous spiral coating is segmented into multiple discrete strip-shaped windings applied in parallel. Each strip can be applied continuously along the circumferential direction, maintaining ease of manufacture while eliminating the overlap problems at the width-directional ends that plague spiral coating methods.
Solution Approach 2:
The parallel strip winding method allows different regions of the sealant layer to have optimized local characteristics. The overlap area is minimized at critical locations (width-directional ends) while maintaining adequate coverage and adhesion in the circumferential direction, creating local quality variations that improve overall performance.
3Area of stationary object
If the overlap area of sealant material is large, then the sealant layer provides adequate coverage, but the thickness variation increases and leads to decline in adhesiveness
Solution Approach 1:
By segmenting the sealant layer into parallel strip windings, the coverage area is maintained through multiple strips working together, while each individual strip contributes minimally to overlap area. This segmentation allows adequate total coverage without the thickness variations caused by large overlap zones.
Solution Approach 2:
The coating parameters are changed from spiral geometry (with inherent overlap accumulation) to parallel strip geometry (with controlled minimal overlap). This parameter change in the coating pattern optimizes the balance between coverage area and thickness uniformity by redistributing how the sealant material is distributed across the tire inner surface.
Data Source
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AI summary
Provided is a pneumatic tire which makes it possible to suppress variation in thickness of a sealant layer by reducing overlapping regions of a sealant material, and achieve improvement in the adhesiveness of a sound absorption layer with respect to the sealant layer. The present invention is provided with: a sealant layer 60 disposed to the tire internal cavity side of an inner liner 50; and a sound absorption layer 70 disposed to the tire internal cavity side of the sealant layer 60. The sealant layer 60 is formed from a belt-shaped sealant material 61 that is stuck to an inner surface 501 of the inner liner 50 while being rotated. The sealant layer 60 has: a plurality of annular circulation parts 62 that are in parallel to the tire circumferential direction and that are disposed in parallel to each other in a state where the sealant material 61 is disposed adjacent to the same in the tire width direction; and a plurality of shift parts 63 which are each provided to a portion of a circulation part 62 in the tire circumferential direction and at each of which the sealant material 61 is shifted to a circulation part 62 located adjacent on one side in the tire width direction.