Silent Chain Rolling Surface Design for Friction Reduction
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Solution Overview
Problem
Conventional silent chains experience durability issues due to frictional wear and increased costs from multiple pins and complex assembly processes, while miniaturization is hindered by large pin holes and increased chain pitch.
Innovation Solution
The silent chain features a pin hole with a plate rolling surface and a pin with a corresponding rolling surface, allowing the plate rolling surface to roll on the pin rolling surface during bending, reducing friction and enabling miniaturization by using a single pin, thus improving durability and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the pin hole is made larger to ensure inner plate rigidity, then the inner plates can maintain structural strength, but the chain pitch increases making miniaturization difficult
Solution Approach 1:
The pin hole is segmented into two functional zones: a rolling contact zone with a curved rolling surface for friction reduction, and a structural support zone that maintains rigidity. This segmentation allows the pin hole to provide both mechanical strength and enable miniaturization without compromising either requirement.
2Strength
If multiple pins are used to connect links, then the structural integrity is improved, but the number of pins and assembly steps increases leading to higher costs
Solution Approach 1:
The functions of multiple pins are merged into a single pin by introducing a rolling surface that reduces friction. The rolling surface allows the single pin to handle both connection and reduced-friction requirements that previously required multiple pins, thereby simplifying the structure and reducing assembly steps while maintaining structural integrity.
3Stability of the object's composition
If the outer peripheral surface of the pin and hole peripheral surface slide on entire contact areas, then the connection is stable, but frictional wear increases reducing durability
Solution Approach 1:
A curved rolling surface is introduced on the pin hole peripheral wall, transforming the sliding contact into rolling contact. This curvature allows the pin to roll within the pin hole during chain operation, significantly reducing frictional wear while maintaining connection stability through the controlled rolling motion.
4Ease of manufacture
If sliding contact is used between pin and inner plate, then the manufacturing process is simple, but frictional loss increases reducing efficiency
Solution Approach 1:
The rolling surface is formed as a curved surface on the pin hole peripheral wall that can be manufactured using standard machining processes. This curved surface enables rolling contact that reduces frictional loss while maintaining manufacturing simplicity, as the rolling surface can be created through conventional machining operations without requiring complex manufacturing steps.
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 enhances chain durability by minimizing friction, reduces the number of pins and assembly steps, and allows for miniaturization, improving applicability to rotary wheels with varying diameters.
Implementation Method 1
a plate rolling surface rolls on the pin rolling surface during chain bending in which the second link bends relative to the first link
Data Source
AI summary
An object of the present invention is to provide a chain reducing friction caused by sliding between the pin and the inner plate, whereby durability is improved, a frictional loss is reduced, and the reduction in size and cost can be implemented. In a silent chain, a guide row and a non-guide row, which are adjacent to each other in a longitudinal direction, are connected together in a bendable manner using a single pin movably inserted into a second pinhole of an inner plate. A hole peripheral wall surface forming the second pin hole has a plate rolling surface, and an outer peripheral surface of the pin has a pin rolling surface. During chain bending, the plate rolling surface rolls on the pin rolling surface.