Agricultural Wheel Rim Profile for Low-Pressure Tyre Retention
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Solution Overview
Problem
Existing wheel constructions for agricultural and off-road vehicles face challenges with tyres inflated at low pressures, which can lead to slipping and difficulty in fitting due to stiffness, offsetting the advantages of improved traction and reduced compaction.
Innovation Solution
A wheel construction with a rim design featuring extended portions on the flanges and side parts with specific concave and convex surfaces, reducing the likelihood of tyre slippage and facilitating easier mounting by minimizing stress and promoting axial movement of the tyre bead during inflation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tyres are inflated to low pressure to improve traction, then traction is improved, but tyre mounting becomes difficult due to stiffness
Solution Approach 1:
The side parts of the rim incorporate curved surfaces with specific radius values (e.g., 15mm, 25mm, 35mm) that create smooth transitions for the tyre bead during mounting. These curved geometries reduce stress concentration and facilitate easier tyre installation while maintaining the structural integrity needed for low pressure operation.
Solution Approach 2:
The rim profile parameters, including the curvature radii of side parts and the radial extension of flange portions, are specifically optimized to balance tyre mounting ease with low pressure performance. By adjusting these geometric parameters, the rim allows stiff tyres to be mounted more easily while maintaining the ability to operate at low pressures for improved traction.
2Reliability
If the rim profile is made stiffer to prevent tyre slippage, then tyre slippage is reduced, but tyre mounting becomes more difficult
Solution Approach 1:
The rim is designed with locally optimized properties: the flange extended portions provide stiffness to prevent slippage, while the side parts with specific curvature radii provide compliance to ease mounting. This spatial variation in structural properties allows the rim to simultaneously achieve both objectives.
Solution Approach 2:
The curved geometries in the side parts with multiple radius values create a profile that is both stiff enough to prevent slippage and compliant enough to facilitate mounting. The specific curvature radii (15mm, 25mm, 35mm) are chosen to optimize this balance between stiffness and mounting ease.
3Strength
If the flange is extended radially inwardly to provide structural support, then structural stiffness is increased, but the rim geometry becomes more complex
Solution Approach 1:
The extended flange portions serve multiple functions simultaneously: they provide structural stiffness to prevent tyre slippage, they create optimal geometric transitions for tyre bead engagement, and they maintain overall rim structural integrity. This multi-functionality reduces the need for additional separate structural elements.
Solution Approach 2:
The invention merges the structural support function with the geometric profile design. The extended flange portions are integrated into the overall rim profile rather than being separate additions, combining structural reinforcement with the functional geometry needed for tyre engagement in a unified structure.
Data Source
AI summary
A wheel includes a rim having inner and outer flanges. A first end of each flange is positioned axially outwardly relative to the second end. A pair of bead seats are positioned one adjacent each flange, and each has an axially outer end connected to a second end of its flange by a flange connecting portion, and an axially inner end connected to one of a pair of side parts. Each side part is positioned between a central well and one of the inner and outer flanges, and connected to the well by a well connecting portion. The outer end of each bead seat is positioned radially outwardly relative to bead seat inner end. At least one of the flanges includes an extended portion which extends radially inwardly, such that a free end of the extended portion is positioned radially inwardly relative to the first end of the respective flange.