Roller Test Bench Noise Reduction via Insulating Layer
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Solution Overview
Problem
Roller dynamometers used in motor vehicle testing emit excessive noise due to structural vibrations and resonances, which are amplified by the interaction between the vehicle wheel and the test bench rollers, exceeding acceptable noise levels, especially during simulated driving scenarios.
Innovation Solution
The implementation of insulating layers made from viscoplastic materials on the outer and inner surfaces of the roller bases and shells, combined with counter-oscillators, to effectively dampen vibrations and reduce noise emissions by converting vibration energy into heat and optimizing damping of oscillating support walls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the vehicle wheel rotates on the test bench roller to simulate driving, then the roadway simulation and measurement capability are improved, but the test bench noise emissions increase due to structural vibrations and resonances
Solution Approach 1:
The patent introduces an insulating layer as an intermediary element between the roller base and the roller shell. This insulating layer acts as a mediator that decouples the vibrational transmission path, preventing resonance amplification while preserving the roller's driving and braking functions. The insulating layer absorbs and dampens vibrations generated during wheel rotation, thereby reducing noise emissions without compromising roadway simulation capability.
Solution Approach 2:
The patent employs composite material construction by combining the roller base, insulating layer, and roller shell into a multi-layer composite structure. Each layer serves a specific function: the roller base provides structural support, the insulating layer provides vibration damping, and the roller shell provides the rolling surface. This composite structure optimizes both noise reduction and roadway simulation performance.
2Strength
If the roller base and roller shell are designed to carry high loads and simulate various road surfaces, then the structural strength and simulation accuracy are improved, but the vibration and noise emissions are amplified due to resonance
Solution Approach 1:
The insulating layer serves as a vibrational intermediary that breaks the direct mechanical coupling between the strong roller base and the roller shell. This mediation allows the structure to maintain high strength for load-bearing and road surface simulation while preventing resonance amplification that would otherwise occur through the rigid connection.
Solution Approach 2:
The patent changes the physical parameters of the roller assembly by introducing the insulating layer with specific damping properties. This modifies the vibrational characteristics of the system, shifting resonance frequencies and reducing vibration amplitude, thereby lowering noise emissions while preserving the structural strength needed for high-load testing.
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 configuration significantly reduces noise emissions by minimizing structural vibrations and resonances, ensuring compliance with stringent NVH (Noise Vibration Harshness) requirements, such as maintaining noise levels below 40 dB at 50 km/h simulated driving speeds.
Implementation Method 1
The insulating layer can be formed from a viscoplastic material which can convert the vibration energy generated by the vibrating machine elements into heat and thereby dampen the vibration process.
Implementation Method 2
an insulating layer for sound and/or vibration damping can be provided on the roller base
Data Source
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AI summary
The rolling test station has a test station roller (1), which has a rolling base (4) and a rolling shell (6). The rolling base carries a rolling shell, where rolling shell has a shell outer surface (13) and a shell inner surface (14). The shell outer surface is formed for contact step with a vehicle wheel (3). An insulating layer (8,9) is provided for the sound or oscillation damping, which is arranged at a rolling base.