Run-Flat Tire Inner Rubber Profile for Emergency Support
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Solution Overview
Problem
Existing run-flat tires face limitations in extending emergency running distance due to inadequate support and increased mechanical stress and heat development from the thin inner rubber layer during emergency operations.
Innovation Solution
The tire features an additional rubber profile with a thickness of 3.5 mm to 12 mm and a width matching the widest belt layer +/- 20 to 30 mm, allowing the emergency ring to rest on it, with a contour opposite to the ring's support surface for optimal power distribution and durability, and optionally omitting the inner layer for improved airtightness and heat balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the inner layer thickness is kept thin (1-2 mm) to maintain tire structure, then the tire flexibility and comfort are improved, but the mechanical stress and heat generation increase during run-flat operation
Solution Approach 1:
The invention divides the inner layer into two functional segments: the original thin inner layer (1-2 mm) for flexibility and comfort, and an additional rubber profile (3.5-12 mm) for mechanical support during run-flat operation. This segmentation allows each layer to optimize its specific function without compromising the other.
Solution Approach 2:
The additional rubber profile is applied locally at the contact area with the emergency running ring, while the rest of the inner layer remains thin. This local quality enhancement provides mechanical support exactly where needed during run-flat operation without affecting overall tire flexibility.
2Duration of action of stationary object
If the additional rubber profile thickness is increased to 3.5-12 mm to reduce mechanical stress, then the run-flat durability is improved, but the inner diameter and air volume are reduced
Solution Approach 1:
The additional rubber profile thickness (3.5-12 mm) exceeds the typical inner layer thickness (1-2 mm), providing sufficient mechanical support for extended run-flat operation. The excessive thickness ensures adequate protection against mechanical stress and heat generation during emergency running.
3Temperature
If the inner layer is omitted beneath the additional rubber profile to improve heat management, then the heat generation is reduced, but the airtightness may be compromised
Solution Approach 1:
The invention extracts (omits) the inner layer from the area beneath the additional rubber profile where it would generate excessive heat during run-flat operation. This removal eliminates the source of unfavorable heat generation while the additional rubber profile provides the necessary support function.
Solution Approach 2:
The additional rubber profile acts as an intermediary between the run-flat ring and the carcass, providing mechanical support and heat management functionality. It mediates the interaction between the rigid run-flat ring and the flexible carcass, distributing forces and reducing heat generation.
4Stability of the object's composition
If the additional rubber profile width is increased to match the widest belt layer +/- 20 to 30 mm to ensure run-flat ring support, then the run-flat stability is improved, but the manufacturing complexity increases
Solution Approach 1:
The additional rubber profile serves multiple functions: providing mechanical support for the run-flat ring, distributing contact forces, managing heat generation, and maintaining airtightness. This multi-functionality justifies the additional manufacturing steps by consolidating multiple requirements into a single component.
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
This configuration enhances the tire's durability and extends emergency running distance by reducing mechanical stress and heat development, ensuring airtightness, and improving power distribution.
Implementation Method 1
This reduces the inner diameter between the surface of the additional rubber profile and the contact surface of the run-flat ring, thereby reducing the relative movement between the rubber profile and the run-flat ring. This results in advantageously reduced heat generation and also advantageously lower mechanical stress.
Implementation Method 2
The thickness of the additional rubber profile is in a range of 3.5 mm to 12 mm, measured at the point of greatest thickness of the additional rubber profile in the radial direction. This results in advantageously reduced heat generation and also advantageously lower mechanical stress.
Implementation Method 3
Due to its sufficient thickness, the additional rubber profile exhibits low air permeability and can adequately replace the largely airtight inner layer. To ensure airtightness, the respective edges of the additional rubber profile, which may be thinner, overlap with the inner layer.
Data Source
Figure 1
AI summary
The invention relates to a vehicle pneumatic tire (1), which is mountable on a rim (2) with a supporting emercency ring (3) extending in the tire cavity (4), with a carcass (5), a tread (6) and at least two belt layers (8a, 8b) of the belt (8), where the vehicle pneumatic tire (1) on its inner surface below the tread (6) shows an additional rubber layer (9), which is arranged around the contour of the vehicle pneumatic tire and on which the emergency ring (3) holds in case of emergency. For a better stability during the emergency operations, the width (10) of the additional rubber layer (9) is in a range from 3,5 mm to 12 mm, measured in the position corresponding to the greatest width of the additional rubber layer in the radial direction.