Non-Pneumatic Tire Beam Reinforcement Layout for Reduced Rut Wander
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Solution Overview
Problem
Non-pneumatic tires (NPTs) used in off-road vehicles experience significant rut wander, a phenomenon where vehicles tend to follow pre-existing ruts, requiring excessive steering input, and there is a lack of understanding and improvement in camber thrust, lateral stiffness, and cornering stiffness in these tires.
Innovation Solution
The design of a tension-based non-pneumatic tire with specific camber thrust stiffness, annular beam configurations, and reinforcement elements, including a flat central tread section and optimized contact patch geometry, to enhance directional stability and reduce rut wander.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If tension-based non-pneumatic tires are used for high speed and high load off-road operation, then load carrying capability and speed capability are improved, but rut wander performance deteriorates
Solution Approach 1:
The patent applies local quality by positioning reinforcement elements at specific locations within the annular beam structure. The reinforcement elements are spaced inboard from the axial extent of the tread, creating zones of differentiated stiffness: higher stiffness at the bead regions for structural support, and lower stiffness in the tread region for improved rut wander performance. This localized variation in mechanical properties allows the tire to simultaneously achieve high load capability and reduced rut wander.
Solution Approach 2:
The patent employs parameter changes by modifying the camber thrust stiffness to a specific range (no more than +0.1 kg/degree per kg at 75% maximum rated load). This parameter adjustment optimizes the tire's response to camber angles, reducing the tendency to follow ruts while maintaining the structural integrity needed for high speed and high load operation.
2Strength
If reinforcement elements are added to the annular beam, then structural strength is improved, but lateral stiffness increases causing worse rut wander
Solution Approach 1:
The patent applies segmentation by dividing the reinforcement strategy into distinct zones. Reinforcement elements are placed inboard from the axial extent of the tread, segmenting the annular beam into reinforced bead regions and less-reinforced tread regions. This segmentation allows the bead areas to provide structural strength while the tread areas maintain compliance for better rut wander performance.
Solution Approach 2:
The reinforcement elements are positioned at specific locations rather than uniformly distributed. By placing them inboard from the axial extent of the tread, the patent creates local quality differences: high reinforcement density near the beads for strength, and lower reinforcement density at the tread for reduced lateral stiffness and improved rut wander.
3Ease of operation
If camber thrust stiffness is reduced to improve rut wander, then directional stability is improved, but load carrying capability may deteriorate
Solution Approach 1:
The patent segments the load-bearing function between the reinforcement elements and the annular beam structure. The reinforcement elements positioned inboard provide structural support for load carrying, while the overall camber thrust stiffness is reduced through the spacing and positioning of these elements, allowing improved rut wander performance without sacrificing load capability.
Solution Approach 2:
The patent changes the camber thrust stiffness parameter to a specific range (no more than +0.1 kg/degree per kg at 75% maximum rated load) while maintaining the structural integrity needed for load carrying. This parameter optimization allows the tire to exhibit reduced rut wander while still supporting high loads through the reinforcement element architecture.
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 tire exhibits improved rut wander performance, reduced camber stiffness, and enhanced endurance by minimizing lateral forces and steering input requirements, while maintaining high-speed and load capabilities.
Implementation Method 1
tension based NPTs have shown merit in off-road usage requiring high speed and high load
Implementation Method 2
a tire with a positive camber thrust will tend to move down the camber incline, whereas a tire with a negative camber thrust will tend to move up the camber incline
Data Source
AI summary
A non-pneumatic tire (100) is provided that has a rim (104) with an axis extending therethrough. An annular support (103) extends outward from the rim in a radial direction. A tread (101) is present that has a surface, and a farthest outer axial extent (804) located at a terminal end of the tread in the lateral direction. An annular beam (200) is located between the annular support (103) and the tread (101) in the radial direction. The annular beam (200) has a reinforcement portion (300) that has a plurality of reinforcing elements. The reinforcing element closest to the farthest outer axial extent in the lateral direction is at a width W1 to the farthest outer axial extent in the lateral direction. W1 is at least 8 millimeters.