Curved Tyre Stud Geometry for Stronger Tread Retention

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Solution Overview

Problem

Studs in vehicle tires tend to detach from the tread band over time, especially in heavy vehicles, due to powerful stresses and tangential movements, leading to reduced performance and durability.

Innovation Solution

Designing studs with a lateral surface featuring gentle curves and uniform pressure distribution to enhance bonding with the tread band, ensuring a substantial increase in retention and gripping capacity on icy roads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional studs with straight or angular lateral surfaces are used, then manufacturing is simple, but the studs detach from the tread band over time due to powerful stresses and tangential movements

Engineering Contradiction:
Improveretention of stud in tread bandVSAvoidstud geometry complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The stud body is designed with a curved lateral surface instead of straight or angular surfaces. The curvature radius varies along the axial direction, creating a smooth transitional profile that enhances bonding with the tread band material and prevents stress concentration, thereby improving retention under powerful stresses and tangential movements.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention changes the geometric parameters of the stud body by introducing a variable curvature radius along the axial direction. This parameter variation optimizes the stress distribution and bonding interface between the stud and tread band, resolving the contradiction between simple manufacturing and reliable retention.

Inventive Principle:
Principle #35Parameter changes

2Force

If studs are used in heavy vehicles, then gripping capacity on icy roads is sufficient, but powerful stresses cause detachment over time

Engineering Contradiction:
Improvegripping force on icy surfaceVSAvoidstud retention under stress
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The curved lateral surface of the stud body distributes the powerful stresses and tangential movements more uniformly along the bonding interface with the tread band. This prevents stress concentration and localized wear that would otherwise lead to detachment under the high forces experienced in heavy vehicle applications.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Ease of manufacture

If studs with abrupt profile changes are used, then manufacturing is easier, but localized wear occurs leading to detachment

Engineering Contradiction:
Improvestud fabrication simplicityVSAvoidresistance to localized wear
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The continuous curved profile eliminates abrupt changes and sharp edges in the stud geometry. This smooth transitional profile prevents stress concentration and localized wear during operation, while still being manufacturable using standard processes, thus resolving the contradiction between manufacturing ease and wear resistance.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The new stud design improves retention in the tread band, enhancing both gripping action and durability, with uniform pressure distribution preventing localized wear and detachment.

Implementation Method 1

at least 80% of the extent of said first lateral surface is curved... allowing the elastomer material of the tread band to bond in a uniform manner to the lateral surface of the stud... uniform pressure distribution preventing localized wear

Methodology Applied
Scientific EffectPressure distribution: Pressure Gradient

Data Source

PatentEP4436795B1Stud and studded tyre for vehicle wheels
Publication Date: 2026.01.28 PIRELLI TYRE SPA
  • EP4436795B1 patent drawingFigure 1~4
  • EP4436795B1 patent drawingFigure 5~9

AI summary

A stud (10; 110; 210; 310) for vehicle tyres comprises a body (11) which extends along a longitudinal axis (Z) of the stud, a gripping pin (12) which extends longitudinally from the body, and a base (13) which extends from the body at the opposite side to the gripping pin. The body (11) comprises a head (20) which is laterally delimited by a first lateral surface (21) and which has an end (17) from which the gripping pin extends, and a shank (30) which extends between the base and the head. The first lateral surface (21) comprises a first portion (23) having a convex profile and a second portion (24) which has a concave profile and which extends between the first portion and the end (17) of the head. The profile of the first portion (23) is connected to the profile of the second portion (24) by means of a first inflection zone.