Ring-Shaped Gear With Vibration System For Noise Reduction
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Solution Overview
Problem
Existing meshed gear structures in vehicle power transmission paths face a trade-off in reducing both booming and rattling noises, which occur at lower frequencies, and gear noise, which occurs at higher frequencies, as increasing gear inertia reduces one type of noise while increasing another.
Innovation Solution
A meshed gear design featuring a ring-shaped gear with an additional vibration system, comprising a ring-shaped mass member and an elastic member, such as metal springs, that increases moment of inertia at lower frequencies to reduce booming and rattling noises while allowing the additional vibration system to increase compliance and reduce gear noise at higher frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If gear inertia is increased to reduce booming and rattling noises, then booming and rattling noises are reduced, but gear noise increases
Solution Approach 1:
The gear structure is segmented into multiple functional components: the gear body, flange, and additional vibration system with mass member and elastic member. This segmentation allows different parts to address different noise issues independently - the gear body and flange provide baseline inertia for booming/rattling reduction, while the additional vibration system specifically targets gear noise through compliance adjustment.
Solution Approach 2:
The additional vibration system introduces dynamic elements (mass member connected by elastic member) that can adapt to varying operating conditions. The system dynamically adjusts compliance characteristics based on frequency - providing stiffness at low frequencies for booming/rattling reduction while increasing compliance at high frequencies for gear noise reduction.
2Object-generated harmful factors
If compliance is increased to reduce gear noise, then gear noise is reduced, but booming and rattling noises increase
Solution Approach 1:
The additional vibration system utilizes mechanical vibration principles where the mass member and elastic member form a vibration system that generates counter-vibrations to reduce gear noise. The system is designed to vibrate at frequencies that counteract the mesh transmission error vibrations, thereby reducing gear noise without compromising low-frequency noise performance.
Solution Approach 2:
The system changes compliance parameters dynamically based on frequency. The elastic member and mass member are designed with specific stiffness and mass characteristics that provide high compliance at high frequencies (reducing gear noise) while maintaining appropriate stiffness at low frequencies (preventing booming and rattling noise increase).
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 effectively reduces both booming and rattling noises by increasing moment of inertia at lower frequencies and reduces gear noise by increasing compliance at higher frequencies, achieving simultaneous noise reduction across different frequency ranges.
Implementation Method 1
an elastic member, such as metal springs, that increases moment of inertia at lower frequencies to reduce booming and rattling noises while allowing the additional vibration system to increase compliance and reduce gear noise at higher frequencies
Implementation Method 2
at least one gear making up the meshed gear has a ring shape, and wherein the one gear has an outer circumferential portion disposed with an additional vibration system
Data Source
AI summary
It is provided a meshed gear for a vehicle disposed in a power transmission path between an engine and drive wheels and made up of a pair of gears meshed with each other, at least one gear making up the meshed gear having a ring shape, and the one gear having an outer circumferential portion disposed with an additional vibration system.