Silent Chain Structure With Variable Link Pitch and Low-Noise Engagement

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Solution Overview

Problem

Conventional chains lack flexibility in design specification due to inner and outer links having the same pitch, leading to limitations in chain plate design and performance, and existing power transmission technologies do not combine the benefits of belt drive's low noise and chain drive's high rigidity.

Innovation Solution

A silent chain with inner and outer links of varying pitches and a chainring design that incorporates sloping sewage discharge grooves to reduce noise and enhance rigidity, allowing for flexible pitch design and stable engagement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional chains use inner and outer links with the same pitch, then the chain structure is simple and easy to manufacture, but the design flexibility and performance optimization are limited

Engineering Contradiction:
Improvechain manufacturing simplicityVSAvoiddesign specification flexibility
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The chain is divided into inner links and outer links with different pitch specifications. The inner links have a first pitch while the outer links have a second pitch, allowing each segment to be optimized independently for specific functional requirements while maintaining overall chain integrity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different pitch values are assigned to different parts of the chain (inner vs outer links) based on their specific functional requirements. This allows local optimization where inner links can be designed for one performance characteristic while outer links are optimized for another, without compromising the entire chain design

Inventive Principle:
Principle #3Local quality

2Object-affected harmful factors

If belt drive transmission is used, then vibration noise is reduced and maintenance is minimized, but rigidity and assembly ease are compromised

Engineering Contradiction:
Improvevibration noiseVSAvoidtransmission rigidity
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The chain incorporates plastic components (inner links, outer links, or combinations) combined with metal elements to achieve a composite structure that reduces vibration and noise while maintaining the rigidity and strength necessary for effective power transmission

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention replaces traditional all-metal chain mechanisms with a hybrid plastic-metal system that combines the low-noise advantages of belt drives with the rigidity and structural integrity of chain drives, effectively substituting pure mechanical metal-on-metal engagement with a more sophisticated mixed-material engagement system

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP4692593A1Silent chain and transmission mechanism having the same
Publication Date: 2026.02.11 KMC CHAIN INDUSTRIAL CO LTD
  • EP4692593A1 patent drawingFigure 1
  • EP4692593A1 patent drawingFigure 2
  • EP4692593A1 patent drawingFigure 3

AI summary

A silent chain (4) includes a plurality of inner links (5), a plurality of outer links (6), and a plurality of rotation rods (7). The inner links (5) are arranged along a transmission direction (D). At least one of the inner links (5) includes an inner chain body (52) that has an engagement protrusion (522), and an inner plate unit (51) that is disposed on an outer side of the inner chain body (52). The outer links (6) are spaced apart from each other and are disposed on outer sides of the inner links (5). The outer links (6) and the inner links (5) are disposed in an alternating arrangement. The rotation rods (7) interconnect the inner links (5) and the outer links (6) in series so that each of the inner links (5) is rotatable relative to each of two adjacent ones of the outer links (6).