Noise Reduction Device with Dynamic Outputter Height
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Solution Overview
Problem
Current noise reduction technologies in hermetically sealed structures like aircraft and railroad vehicles are inadequate in effectively mitigating noise from multiple sources, particularly low-frequency and random noise, due to limitations in noise source identification and control sound positioning.
Innovation Solution
A noise reduction device comprising a noise detector, noise controller, and control sound outputter, where the control sound outputter is strategically positioned at a height of L×sin θ+8 cm above a reference plane, with θ between -4 and 12 degrees, to optimize noise cancellation by generating a control sound signal opposite in phase to the detected noise, effectively reducing noise levels in a space surrounded by a shell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional noise reduction methods are used in hermetically sealed structures, then some noise mitigation is achieved, but the effectiveness is insufficient particularly for low-frequency and random noise from multiple sources
Solution Approach 1:
The patent divides the noise control space into multiple control points (first control point near the head position, second control point near the ear position) and uses multiple independent control sound outputters (first and second outputters) to address different noise sources and frequency ranges. This segmentation allows the system to independently optimize noise reduction at different locations and for different noise types, thereby improving overall effectiveness for complex multi-source noise environments.
Solution Approach 2:
The patent extends the traditional single-point noise control approach by introducing a vertical dimension through the specific height positioning formula (L×sin θ+8 cm). This dimensional adjustment optimizes the spatial relationship between the control sound outputter and the control points, enabling effective noise reduction across a broader frequency spectrum including low-frequency components that were previously difficult to control in sealed structures.
2Object-affected harmful factors
If the control sound outputter is positioned at the conventional height, then the device structure is simple, but the noise cancellation effectiveness is reduced
Solution Approach 1:
The patent transforms the fixed positioning parameter into a dynamic calculation based on the recliner angle θ and length L. By using the formula height = L×sin θ+8 cm, the system adapts the outputter position to match the actual spatial relationship between the seat and control points. This parameter-based positioning optimizes noise cancellation effectiveness while maintaining implementation simplicity through a straightforward mathematical relationship.
3Object-affected harmful factors
If multiple control points are monitored, then noise reduction coverage is improved, but the system complexity increases
Solution Approach 1:
The patent combines multiple noise detection and control functions into an integrated system where the first and second noise detectors work together with the first and second control sound outputters. The noise controller coordinates all components to generate control sounds that simultaneously address noise at both the first control point (head position) and second control point (ear position), achieving broad noise reduction coverage without requiring separate independent systems for each control point.
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 device achieves significant noise reduction across a wide frequency range by optimizing the positioning of noise detectors and control sound outputters, enhancing noise cancellation even in complex noise environments with multiple sources, thereby improving passenger comfort and reducing noise-related disturbances.
Implementation Method 1
generates a control sound signal for reducing the noise detected by the noise detector... generating a control sound signal opposite in phase to the detected noise
Data Source
AI summary
A noise reduction device includes: a noise detector that detects noise in a space at least partially surrounded by a shell; a noise controller that generates a control sound signal for reducing the noise detected by the noise detector; and a control sound outputter that outputs control sound to the space based on the generated control sound signal. A seat that is reclinable including a recliner having a seat surface at a variable angle with respect to a reference plane is provided in the space. When L (cm) represents the length of the recliner in the front-to-back direction, the control sound outputter is provided at a height of L.times.sin .theta.+8 (cm) above the reference plane where .theta. is between two degrees and eight degrees, inclusive.