Non-pneumatic Tire Spoke Pre-compression Fixture
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Solution Overview
Problem
Existing methods for constructing non-pneumatic tires lack the ability to apply forces other than pre-tensioning to the spokes during assembly, which can lead to fatigue and suboptimal stress-strain performance.
Innovation Solution
A fixture with mechanical elements that apply compression to the spokes before attaching them to the shear band, using a radial movement member and bladders to push the spokes into a compressed configuration, followed by adhesive attachment to maintain pre-compression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spokes are pre-tensioned during assembly, then spoke fatigue is reduced and stress-strain performance is optimized, but the ability to apply other types of forces (such as pre-compression) is limited
Solution Approach 1:
Instead of pre-tensioning the spokes (pulling them outward), the invention applies pre-compression (pushing them inward) by moving mechanical elements radially inward. This inverted approach to pre-stressing spokes opens new possibilities for force application and performance optimization.
Solution Approach 2:
The fixture employs a radial movement member that can dynamically adjust the radial position of mechanical elements, enabling transition between different force application states (compression and tension) and allowing versatile control over spoke pre-stressing.
2Force
If mechanical elements are moved radially inward to compress spokes, then pre-compression is achieved, but the spokes must be subsequently attached to the shear band which requires precise positioning
Solution Approach 1:
The mechanical elements are moved radially inward to compress and position the spokes precisely before the spokes are attached to the shear band. This preliminary positioning action ensures that spokes are correctly aligned and compressed before final attachment, maintaining manufacturing precision.
3Force
If a fixture with movable mechanical elements is used to apply pre-compression, then spoke pre-compression is achieved, but the device complexity increases
Solution Approach 1:
The radial movement member serves multiple functions: it moves mechanical elements radially to apply compression, positions spokes during assembly, and maintains pre-compression forces. This multi-functionality reduces the need for separate mechanisms, thereby limiting the increase in device complexity.
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 solution ensures that the spokes are pre-compressed within the shear band, reducing fatigue and optimizing the stress-strain curve of the tire, allowing for improved performance and extended lifespan.
Implementation Method 1
a first and second bladder are positioned onto the fixture and are expanded radially outwardly
Implementation Method 2
adhesive is applied to the outer radial ends of the spokes, and the retaining elements are released and the spokes are pushed against the shear band and pressed thereon until the adhesive is cured
Data Source
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AI summary
An apparatus for assembling a non-pneumatic tire is provided that includes a plurality of spokes attached to a hub, a frame, and a plurality of mechanical elements disposed between and engaging successive spokes. The spokes extend to locations radially inward and radially outward of the locations of engagement with the mechanical elements. A radial movement member moves the mechanical elements in a radial direction. The spokes are compressed by the mechanical elements, and retaining elements engage the mechanical elements to hold them and the spokes in this position. Release by the retaining elements and outward radial movement of the mechanical elements urge the spokes toward a shear band that is outward in the radial direction. Adhesive located between the spokes and the shear band is pressed there between through this urging to result in the spokes being attached to the shear band in a state of pre-compression.