Forestry Tyre Shoulder Profile for Uniform Ground Pressure
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Solution Overview
Problem
Existing pneumatic tyres for forestry vehicles do not effectively distribute ground pressure uniformly across the tread section, leading to increased damage to plant populations and root systems, especially on soft terrains, and require higher operating pressures.
Innovation Solution
A pneumatic tyre design with increased rubber material in the shoulder regions and a box-like shape when inflated, featuring a carcass framework with a convex tread surface and groove structure, enhancing ground contact area and uniform pressure distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional rounded tyre shape is used, then manufacturing is simpler, but ground pressure distribution is non-uniform and vegetation damage increases
Solution Approach 1:
The tyre tread width is varied along the circumferential direction, creating different local characteristics: wider at shoulder regions for better ground contact and vegetation protection, and narrower at center region for improved mobility. This local variation in geometry resolves the contradiction by optimizing different regions for different functions.
Solution Approach 2:
The tyre design breaks the traditional symmetric rounded shape by introducing asymmetric width variations along the circumferential direction. The tread width profile creates a box-like inflated shape with distinct shoulder and center regions, improving ground pressure distribution while maintaining manufacturability through mold design.
2Speed
If higher operating pressure is used, then tyre mobility improves, but ground pressure on vegetation increases causing damage
Solution Approach 1:
The tyre distributes ground pressure differently across its tread width: shoulder regions with greater width and contact area provide lower local ground pressure to protect vegetation, while the center region maintains adequate pressure for mobility. This local differentiation allows the tyre to operate at lower overall pressures without sacrificing mobility.
Solution Approach 2:
Instead of controlling ground pressure solely through inflation pressure (one dimension), the invention introduces tread width variation along the circumferential direction as an additional dimension of control. This geometric parameter allows independent optimization of ground pressure distribution and mobility characteristics.
3Area of stationary object
If more rubber material is added to shoulder regions, then ground contact area increases improving vegetation protection, but tyre weight increases
Solution Approach 1:
The tyre design concentrates additional rubber material specifically in the shoulder regions where it is most needed for vegetation protection and ground contact, while maintaining appropriate material distribution in the center region. This localized material placement increases ground contact area without proportionally increasing overall tyre weight.
Data Source
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AI summary
A pneumatic tyre (100) of rubber material for forestry vehicles, including a shoulder surface (34) defining in an axial direction (A) an overall tread width (TW) and a maximum selected distance (SD) from an equatorial plane (EP) of the tyre. Thickness of the rubber material is defined by distances (RT) between convex shapes of a carcass (52) and a ground-engaging tread surface (54) of the tyre, measured in a direction normal to the convex shape of the carcass (52). As a reference, at the equatorial plane (EP) the thickness is defined as 100%. At a selected distance (SD) of 67% of the maximum selected distance (SD), the thickness is defined as from 118% to 167%, or from 130% to 155%, or from 138% to 151%, of the thickness at the equatorial plane (EP). At a selected distance (SD) of 83%, the thickness is defined as from 144% to 203%, or from 157% to 187%, or from 169% to 182%. According to an example, at a selected distance (SD) of 91%, the thickness is defined as from 160% to 225%, or from 173% to 208%, or from 187% to 202%.