Cushioned Sprocket Teeth for Chain Noise and Vibration Reduction
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Solution Overview
Problem
Existing drive mechanisms with sprockets and chains face issues of noise and vibration due to tension fluctuations and periodic load torque changes, limiting load capacity and production methods, and requiring additional noise reduction measures.
Innovation Solution
A sprocket with a high-rigidity base body and a cushioning layer varying in thickness on its tooth portions, which absorbs shock and dynamically adjusts to mitigate tension fluctuations, allowing for weight reduction and increased productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a phase variation pattern is used to reduce tension fluctuations, then noise and vibration are suppressed, but order noises corresponding to the frequency are still generated due to periodic load torque changes
Solution Approach 1:
The cushioning layer thickness is varied to change the engagement characteristics between sprocket teeth and chain, dynamically adjusting the phase of tooth engagement to counteract periodic load torque changes and reduce order noises
Solution Approach 2:
The cushioning layer is designed with varying thickness to create dynamic engagement characteristics that adapt to periodic load variations, allowing the sprocket to dynamically cancel torque changes rather than using a static phase variation pattern
2Object-affected harmful factors
If plastic sprockets are used, then meshing noise is reduced, but load capacity becomes insufficient
Solution Approach 1:
The sprocket combines a metal base body (providing high strength and load capacity) with a cushioning layer (providing noise reduction and shock absorption), creating a composite structure that achieves both low noise and high load capacity
Solution Approach 2:
The cushioning layer is applied locally on the tooth faces where contact with the chain occurs, providing noise reduction only at the critical contact zones while maintaining the overall structural strength of the metal base body
3Productivity
If gear hobbing is used for production, then productivity is high, but it is not applicable because the pitch of the sprocket teeth is not constant
Solution Approach 1:
The sprocket is segmented into two independently manufacturable components: a standard pitch metal base body and a separate cushioning layer, allowing the base body to be produced using high-productivity gear hobbing while the cushioning layer is added subsequently to provide the non-constant pitch effect
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 solution effectively reduces noise and vibration by absorbing shock and adjusting to torque changes, enabling weight reduction and cost savings while maintaining high strength and flexibility in production methods.
Implementation Method 1
a cushioning layer provided at least on a tooth face of each of the plurality of tooth portions and forming the sprocket teeth together with the tooth portions, the sprocket teeth including the cushioning layer that varies in thickness
Data Source
AI summary
To provide a sprocket that reduces the influence of tension fluctuations concurrent with load torque changes to suppress noise and vibration and that allows for a weight reduction while retaining high strength as well as enables high productivity, and a drive mechanism that uses this sprocket. Sprocket teeth are configured by providing a cushioning layer on tooth faces of tooth portions of a sprocket base body made of a high-rigidity material. The sprocket teeth include the cushioning layer that varies in thickness.