Run-Flat Tire Emergency Layer Wax Grease Friction
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Solution Overview
Problem
Pneumatic vehicle tires face destruction during emergency operation due to excessive friction and heat generation when running with low or no overpressure, leading to reduced mileage and potential vehicle immobilization, especially in critical situations like breakdowns.
Innovation Solution
The emergency running layer is made of elastomeric material with a higher proportion of wax and/or grease than the carcass rubber, which reduces friction between the tire and support device, and is designed to absorb load, with specific thermal conductivity and profiling to enhance heat dissipation and friction reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a support device is mounted to enable run-flat operation, then the tire can continue to bear load with low or no pressure, but excessive friction and heat generation occur between the tire and support device
Solution Approach 1:
The patent modifies the material composition parameters of the emergency running layer by incorporating elastomeric material with higher wax and/or grease content compared to the carcass rubber. This parameter change in material composition reduces the friction coefficient between the tire and support device, thereby reducing heat generation during run-flat operation while maintaining load-bearing capability
Solution Approach 2:
The patent creates a composite material structure by combining elastomeric material with wax and/or grease additives in the emergency running layer. This composite formulation provides both the structural integrity needed for run-flat support and the lubricating properties to reduce friction-induced heating at the contact interface with the support device
2Temperature
If grease is added to the wheel system during tire mounting to reduce friction, then friction during run-flat operation is reduced, but the mounting process becomes more complex and grease is distributed throughout the wheel system rather than concentrated at the friction point
Solution Approach 1:
The patent merges the lubricating function with the structural emergency running layer by incorporating elastomeric material containing wax and/or grease directly into the tire structure. This integration eliminates the need for separate grease application during mounting, simplifying the mounting process while ensuring the lubricant is precisely positioned at the friction contact point between the emergency running layer and support device
Solution Approach 2:
The emergency running layer is designed to be self-lubricating through the inclusion of elastomeric material with embedded wax and/or grease. This self-service approach eliminates the need for external grease application during mounting, as the lubricating components are already integrated into the tire structure and will automatically function at the friction interface during run-flat operation
3Length of moving object
If the radial inner circumference of the tire is larger than the radial outer circumference of the support device, then the tire can be mounted on the rim, but continuous run-flat operation causes mechanical wear and destruction through friction
Solution Approach 1:
The patent changes the material parameters of the emergency running layer by using elastomeric material with higher elastomer content and embedded wax/grease compared to conventional tire materials. This parameter change reduces the friction coefficient at the contact interface with the support device, thereby reducing wear rate and extending the duration of run-flat operation before tire or support device destruction occurs
Solution Approach 2:
The patent employs composite material formulation in the emergency running layer, combining elastomeric base material with lubricating additives (wax and/or grease). This composite structure provides both the mechanical properties needed for structural integrity during run-flat support and the low-friction surface properties that reduce wear, thereby extending the operational mileage of the wheel system in run-flat mode
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 design significantly increases the mileage of the wheel system in emergency operations by reducing mechanical stress and heat generation, delaying tire and support device destruction, and simplifies tire mounting by eliminating the need for additional lubrication.
Implementation Method 1
the elastomeric material contains at least one wax and/or at least one grease, wherein the elastomeric material has a higher weight percentage (wt%) of wax and/or grease than the carcass rubber lining
Implementation Method 2
specific thermal conductivity and profiling to enhance heat dissipation
Data Source
Figure 1~2
Figure 3~6
AI summary
A vehicle pneumatic tire (4) for a wheel system (1) comprising a rim (2), the vehicle pneumatic tire (4) mounted on the rim (2), and a support device (5) mounted axially inside the vehicle pneumatic tire (4) on the rim (2), which bears the load in run-flat conditions, wherein the vehicle pneumatic tire (4) has an inner layer (12). The objective is to provide a vehicle pneumatic tire (4) for a wheel system (1) with a support device (5) that is characterized by increased mileage of the wheel system (1) in run-flat conditions and simpler mounting. This objective is achieved by providing the vehicle pneumatic tire (4) with a run-flat layer (13) made of elastomeric material radially inside the inner layer (12), wherein the elastomeric material contains at least a wax and/or at least a grease, and wherein the elastomeric material has a higher weight fraction (wt.-%) has more wax and/or grease than the carcass rubber coating and wherein the emergency running layer (13) is arranged such that in emergency running the emergency running layer (13) and the support device (5) contact and that the load absorption by the support device (5) takes place at least partially in the area of the contact surface between the emergency running layer (13) and the support device (5).