Trapezoidal Support Wind Tunnel Belt Unit
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Solution Overview
Problem
Existing belt test stands for motor vehicles in wind tunnels have a large wind-exposed area, leading to increased error forces and reduced measurement accuracy due to excessive exposure of the belt unit to air currents.
Innovation Solution
A trapezoidal support is positioned below the endless belt between the drums, raised above the normal zero position, with the test stand cover extending over the drums to minimize the wind-exposed area, and a porous material with air application is used to reduce friction and turbulence, ensuring the belt runs symmetrically and minimizing the area exposed to air currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the belt test stand uses a conventional support position at normal zero level, then the structure is simple and easy to manufacture, but the wind-exposed area is large causing increased error forces
Solution Approach 1:
The support is positioned at a height above the normal zero level, transitioning from a two-dimensional planar arrangement to a three-dimensional configuration. This vertical positioning allows the test stand cover to extend further over the drums, reducing the wind-exposed area of the belt unit while maintaining structural simplicity.
2Measurement precision
If the test stand cover extends further over the drums to reduce wind-exposed area, then measurement accuracy improves, but the device complexity increases
Solution Approach 1:
The support structure and test stand cover are merged into an integrated assembly. The support at the elevated position serves dual purposes: it maintains the belt unit structure while simultaneously enabling the test stand cover to extend over the drums, reducing wind exposure without adding separate complex components.
3Measurement precision
If the belt contact area is reduced to match tire shuffle, then error forces are minimized, but the stability of the vehicle on the belt decreases
Solution Approach 1:
The elevated support acts as an intermediary element that allows the test stand cover to extend over the drums, creating a protected area that reduces wind exposure. This intermediary structure enables the belt contact area to be minimized while maintaining vehicle stability through the support's positioning and the cover's protective extension.
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 reduces error forces and enhances measurement accuracy by minimizing the wind-exposed area to match the tire contact area, improving the precision of force and moment measurements in wind tunnel tests.
Implementation Method 1
a porous material with air application is used to reduce friction and turbulence
Data Source
AI summary
The invention relates to a belt unit in a wind tunnel balance for motor vehicles, in particular for determining forces and moments acting on a motor vehicle in a wind tunnel, wherein an area exposed to wind is minimized by means of a trapezoidal support, which is raised with respect to a normal zero position, and appropriately adapted test stand covers. The wind-exposed area of the endless belt of the belt test stand can be reduced here to a value which is only slightly above the necessary wheel contact area (tire shuffle). As a result, error forces can be reduced further, so that the result is highly increased measurement accuracy.