Pneumatic Tire Inner Lateral Grooves for Wear and Noise
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Solution Overview
Problem
Pneumatic tires face challenges in achieving improved uneven wear resistance without compromising drainage performance and noise reduction, as existing designs either enhance wear resistance at the expense of drainage or vice versa.
Innovation Solution
The tire design incorporates three or more circumferential main grooves with inclined inner lateral grooves, featuring first and second inner lateral grooves of varying widths and depths, along with acute and obtuse-angle corner parts, to distribute sound pressure and enhance rigidity, while ensuring effective drainage through widened parts of the second inner lateral grooves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the groove width of the inner lateral grooves is reduced to enhance rigidity of the inner blocks, then uneven wear resistance is improved, but drainage performance deteriorates and wet performance deteriorates
Solution Approach 1:
The inner lateral grooves are designed with non-uniform width characteristics: the first inner lateral grooves have a narrow-width part on the axially inner side and a wide-width part on the axially outer side, while the second inner lateral grooves have constricted and widened parts. This local variation in groove width provides different functions in different regions, improving uneven wear resistance while maintaining drainage capability.
Solution Approach 2:
The inner lateral grooves are segmented into two types (first and second inner lateral grooves) that are alternately arranged in the circumferential direction. Each type has distinct width characteristics, creating a segmented structure that simultaneously addresses wear resistance and drainage requirements through the combined effect of different groove configurations.
2Reliability
If the groove width of the inner lateral grooves is reduced to improve rigidity of the inner blocks, then uneven wear resistance is improved, but wet performance deteriorates
Solution Approach 1:
The alternating pattern of narrow and wide groove sections, combined with two types of inner lateral grooves having different width characteristics, creates local variations that maintain water evacuation capability in wet conditions while providing sufficient rigidity to the inner blocks for improved uneven wear resistance.
Solution Approach 2:
The segmentation into first and second inner lateral grooves with alternating width characteristics ensures that some groove sections maintain width for drainage and wet performance, while other sections provide rigidity enhancement, thereby resolving the contradiction between wear resistance and wet performance.
3Object-generated harmful factors
If inner lateral grooves are inclined at a larger angle to reduce pitch sound, then noise performance is improved, but rigidity of inner blocks decreases leading to increased uneven wear
Solution Approach 1:
The groove width is varied locally along the axial direction with narrow-width and wide-width parts, and the alternating first and second inner lateral grooves create local rigidity enhancements at specific positions. This allows the use of larger inclination angles for noise reduction while compensating for rigidity losses through localized structural reinforcement.
Solution Approach 2:
The segmentation into alternating first and second inner lateral grooves with different width characteristics creates a segmented rigidity distribution that counteracts the rigidity reduction caused by larger groove inclination angles, thereby maintaining uneven wear resistance while achieving noise reduction.
Data Source
AI summary
A tread portion of a pneumatic tire includes inner land portions between outer circumferential main grooves disposed most on tread ground-contact end sides and at least one inner circumferential main groove on the inner side thereof. The inner land portions are divided into inner blocks by inner lateral grooves inclined at an angle α of 10 to 40°. The inner lateral grooves consist of first inner lateral grooves and second inner lateral grooves which are alternately arranged in a circumferential direction. The first inner lateral grooves include a wide-width part connecting to the outer circumferential main groove and a narrow-width part connecting to the inner circumferential main groove.