Stud Pin Retention via Cross-Sectional Area Ratio
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Solution Overview
Problem
Conventional snow tires with stud pins tend to fall out when traveling on concrete or asphalt surfaces due to the higher forces exerted by these surfaces, leading to reduced performance on ice and increased stud pin loss.
Innovation Solution
A stud pin design featuring a buried base portion and a tip portion with a specific cross-sectional area ratio, inclined side surfaces, and a concave-polygonal tip end surface, which reduces the moment of forces acting on the stud pin and enhances its retention within the tire tread.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If stud pins are embedded in stud pin installation holes on concrete or asphalt surfaces, then the stud pins provide grip on icy road surfaces, but the high forces from hard road surfaces cause many stud pins to fall out during braking, accelerating, or cornering
Solution Approach 1:
The stud pin is divided into three distinct segments: a tip portion for ice contact, a connection portion for structural transition, and a buried base portion for secure embedding. This segmentation allows each part to be optimized for its specific function, with the connection portion acting as a stress buffer between the tip and base portions to reduce the moment of forces during embedding.
Solution Approach 2:
Different portions of the stud pin have different cross-sectional areas tailored to their specific functions. The tip portion has a smaller cross-sectional area for ice contact, while the buried base portion has a larger cross-sectional area for secure embedding. The connection portion features an intermediate cross-sectional area that transitions between the two, creating a stress distribution that reduces the moment of forces during embedding.
2Reliability
If stud pins are embedded firmly in expanded stud pin installation holes, then stud pins are prevented from falling out, but the number of stud pins falling out increases when traveling on concrete or asphalt surfaces
Solution Approach 1:
The stud pin is pre-configured with a specific geometric structure featuring a connection portion with a cross-sectional area larger than the tip portion's cross-sectional area. This preliminary structural design ensures that when the stud pin is embedded in the stud pin installation hole, the moment of forces acting on it is reduced, preventing ejection before the harmful effect of forceful road surface contact occurs.
3Force
If the stud pin tip portion has a larger cross-sectional area, then it provides better grip on ice, but the moment of forces acting on the stud pin during embedding increases causing more stud pins to fall out
Solution Approach 1:
The stud pin features locally optimized cross-sectional areas: the tip portion has a smaller cross-sectional area (S1) for reduced moment during embedding, while the connection portion has a larger cross-sectional area (S2) where S2/S1 is between 1.25 and 7.5. This local quality differentiation allows the tip to provide sufficient ice grip while the connection portion's larger area reduces the moment of forces, preventing stud pin ejection during embedding.
Data Source
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AI summary
Provided is a stud pin fitted into a pneumatic tire that maintains the performance on ice of the pneumatic tire and that does not easily fall out. Also provided is a pneumatic tire fitted with the stud pin. The stud pin fitted into a tread portion of a pneumatic tire comprises a buried base portion extending in a direction, the buried base portion securing the stud pin in the tread portion by being pressed by a side surface of the stud pin installation hole upon the stud pin being embedded in the stud pin installation hole, and a tip portion connected to an end portion of the buried base portion in the extending direction, the tip portion protruding past the tread portion and coming into contact with a road surface upon the buried base portion being embedded in the stud pin installation hole. The tip portion comprises a tip end surface perpendicular to the extending direction of the buried base portion, and a connection portion of the tip portion with the buried base portion has a cross-sectional area in a plane orthogonal to the extending direction of the buried base portion greater than an area of the tip end surface. The stud pin is fitted into the tread portion of the pneumatic tire.