Electronic Horn Sound Directivity via Nested Acoustic Chambers
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Solution Overview
Problem
Existing electronic horns face challenges in efficiently outputting warning sounds with sufficient directivity due to the limitations of plate-shaped horn caps, which often result in soft and poorly directed sound emission.
Innovation Solution
The design incorporates a plate-shaped oscillator, a resonator with an opening forming a resonance space, a buffer chamber, and a series of sound amplifying chambers that utilize the megaphone effect to amplify and direct the warning sound forwardly, maintaining a compact shape by curving paths and providing coverage around the resonator's circumference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a plate-shaped horn cap is used to adjust sound directivity, then the horn structure becomes compact, but the warning sound cannot be efficiently output forwardly with sufficient directivity
Solution Approach 1:
The horn cap is divided into multiple functional chambers: a resonator for generating sound, a buffer chamber for acoustic pressure regulation, and multiple sound amplifying chambers (first and second) for directional sound guidance. This segmentation allows each chamber to perform its specific function optimally, achieving both compact shape and sufficient sound directivity.
Solution Approach 2:
The sound amplifying chambers utilize inverse curvature paths and three-dimensional spatial arrangement to guide sound waves. The first sound amplifying chamber guides sound along a path that inversely curves while gradually increasing in diameter, and the second sound amplifying chamber further reflects sound to the front, utilizing spatial dimensionality to achieve directional control without increasing overall footprint.
2Ease of operation
If sound amplifying chambers are added to improve sound directivity, then warning sound output efficiency improves, but the horn body protrudes in the forward-rearward direction
Solution Approach 1:
The sound amplifying chambers are designed with inverse curvature surfaces that gradually increase in diameter. This curved, spherical-like geometry allows sound waves to be guided and reflected efficiently while maintaining a compact radial profile, preventing the horn body from protruding significantly in the forward-rearward direction.
Solution Approach 2:
The multiple sound amplifying chambers are arranged concentrically around the resonator, with the first sound amplifying chamber surrounding the resonator and the second sound amplifying chamber surrounding the first. This nested arrangement allows multiple sound amplification functions to be packed into a compact radial space, minimizing forward-rearward protrusion.
3Shape
If the oscillator is positioned close to the horn body walls to maintain compact shape, then the horn becomes more compact, but thermal stress occurs on the oscillator causing amplitude changes
Solution Approach 1:
An intermediate element is introduced between the oscillator and the horn body walls. This intermediary component provides thermal isolation, preventing heat generated by the oscillator during operation from transferring to the horn body walls, thereby maintaining oscillator amplitude stability while allowing compact positioning.
Solution Approach 2:
The intermediate element acts as a sacrificial thermal barrier that can be easily replaced if needed, protecting the expensive and sensitive oscillator from thermal damage. This allows the oscillator to be positioned close to the walls for compactness without compromising long-term reliability.
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 enables efficient and directional output of warning sounds forwardly, enhancing sound directivity while maintaining a compact horn body shape, and prevents thermal stress on the oscillator by ensuring it does not contact the horn body walls.
Implementation Method 1
a piezoelectric element (52) that excites the oscillator (51)
Implementation Method 2
a resonator (7) provided with an opening (71) in a portion thereof and covering forward of the oscillator (51) such that a resonance space (S) is defined between the resonator (7) and the oscillator (51)
Implementation Method 3
one or more first sound amplifying chambers (MH1) that guide(s) a warning sound, which is output from (through 0 the buffer chamber (BR), to the front or to the rear of an outer circumference along a path that inversely curves while gradually increasing in diameter
Data Source
AI summary
An electronic horn for use, e.g., in a vehicle, includes a piezoelectric element (52) that excites a plate-shaped oscillator (51). A resonator (7) is provided with an opening (71) and covers forward of the oscillator such that a resonance space (S) is defined between the resonator and the oscillator. An inner cylinder (62) and an outer conical housing (63) are provided concentrically around the resonator. A circular cover (8) covers the inner cylinder (62) and the outer conical housing (63) from the front, such that a buffer chamber (BR), at least one first sound amplifying chamber (MH1), and a second sound amplifying chamber (MH2) are defined around an entire circumference of the opening of the resonator.