Stud Pin Anisotropic Flange Rotation Suppression
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Solution Overview
Problem
Stud pins with non-arc shaped flanges can easily rotate within their mounting holes due to shear forces from icy road surfaces, leading to reduced fastening and increased likelihood of falling out, as they incline and lose resistance against the pin inserting hole.
Innovation Solution
A stud pin design featuring a lower flange with an anisotropic profile shape, including multiple protrusion and recess portions, which increases holding strength and suppresses rotation, preventing the stud pin from falling out by enhancing the contact area and grip within the pin inserting hole.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stud pin includes a lower flange with a non-arc shaped profile, then the stud pin can suppress falling out from the pin inserting hole, but the stud pin rotates easily within the hole due to shear force from icy road surfaces
Solution Approach 1:
The lower flange is designed with an asymmetric profile shape that is longer in the tire circumferential direction than in the tire lateral direction. This asymmetric geometry creates differential engagement with the pin inserting hole walls, generating resistance to rotational movement while maintaining prevention of complete extraction. The asymmetric shape ensures that when shear force acts on the stud pin, the flange engages more strongly against rotation rather than allowing the pin to incline and fall out.
2Strength
If the stud pin is embedded in the pin inserting hole, then the stud pin is firmly fastened, but the hole expands in diameter reducing fastening force
Solution Approach 1:
The lower flange is designed with a profile shape that anticipates and prevents hole expansion before it occurs. By providing a flange with specific geometric dimensions and shape characteristics, the design pre-establishes constraints that limit the expansion of the pin inserting hole during embedding. This preliminary geometric constraint ensures that the hole does not expand excessively, maintaining fastening force while allowing proper installation of the stud pin.
3Force
If the stud pin receives shear force from icy road surface, then the stud pin inclines to fall against the pin inserting hole, but this reduces fastening force and increases rotation
Solution Approach 1:
The asymmetric profile shape of the lower flange, being longer in the tire circumferential direction, creates unequal engagement surfaces when shear force acts on the stud pin. This asymmetric geometry ensures that the flange engages more strongly against the pin inserting hole walls in the direction that prevents inclination and rotation, rather than allowing the pin to fall against the hole. The asymmetric design transforms the shear force into beneficial engagement pressure that maintains fastening force.
Data Source
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AI summary
The stud pin includes a tip including an end surface that comes into contact with a road surface, a body portion that supports the tip; and a lower flange connected to the body portion at an end on an opposite side to the end surface. A profile shape of the lower flange is an anisotropic shape in which, of imaginary rectangles circumscribing the profile shape, a first smallest rectangle with the shortest side of its four sides being the shortest and/or a second smallest rectangle with the longest side of its four sides being the shortest includes short sides and long sides of different lengths. The profile shape includes four or more first protrusion portions that project in the longitudinal direction parallel with the long sides and two second protrusion portions that project in the lateral direction parallel with the short sides.