Silent Chain Curved Back Face Reduces Friction Loss
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Solution Overview
Problem
Conventional silent chains experience increased friction loss and destabilization due to full slidable contact with chain guides, leading to vibrations, noise, and reduced transmission efficiency.
Innovation Solution
The silent chain design features a curved back face on inner link plates and a low-rigid guide link plate with a crotch portion and ear portions, reducing contact area with the chain guide, and employing a preload operation to stabilize the chain and improve pitch accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the whole back face of the inner link plate is in slidable contact with the chain guide, then the chain is guided stably, but friction loss increases
Solution Approach 1:
The invention applies local quality by providing a curved surface portion on the back face of the inner link plate that contacts the chain guide, while other portions have different configurations. This localized curvature concentrates contact to a specific area, reducing overall friction loss while maintaining stable guidance where needed.
Solution Approach 2:
The invention uses a curved surface portion instead of a flat back face on the inner link plate. This curvature reduces the contact area with the chain guide, thereby reducing friction loss while still providing adequate guidance stability through the curved contact interface.
2Reliability
If guide link plates have a crotch portion configuration, then edge-like abrasion is prevented, but contact area with chain guide is reduced causing vibrations
Solution Approach 1:
The invention differentiates between inner link plates and guide link plates in their contact configurations. Inner link plates have curved surfaces for reduced friction, while guide link plates have crotch portions for durability. This localized differentiation allows each component to optimize its function without compromising overall chain stability.
3Stability of the object's composition
If lengths from pin hole centers to back faces are equalized, then chain guidance is improved, but friction loss increases due to full contact
Solution Approach 1:
The invention modifies the back face configuration of inner link plates by adding a curved surface portion, deviating from the conventional equalized flat surface design. This curvature reduces the contact area with the chain guide, thereby reducing friction loss while maintaining adequate guidance through the curved contact interface.
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 reduces friction loss by approximately 25% and stabilizes the chain, preventing vibrations and improving engagement accuracy and durability, thereby enhancing transmission efficiency and reducing noise.
Implementation Method 1
This configuration reduces friction loss by approximately 25%
Implementation Method 2
employing a preload operation to stabilize the chain and improve pitch accuracy
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3
AI summary
A back face of each inner link plate (3) of the chain is curved convexly. Heights from a pitch line (L-L) connecting centers of pin holes of inner and guide link plates to the convex apex portion (12) of the inner link plate (3) and to an apex portion of the guide link plate (5) are equalized. The convex apex portions (12) are brought into contact with a guide face (30a) of the chain guide (30) per every pitch and the ear apex portions (20) are brought into contact with the chain guide (30) per every pitch while being shifted by a half pitch from the convex apex portions (12).