Silent Chain and Chainring With Variable Pitch for Low-Noise Rigidity
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Solution Overview
Problem
Conventional chains are limited in design flexibility due to the need for inner and outer links with the same pitch, leading to limitations in chain plate design, and conventional chainrings lack integration of belt drive transmission's low noise and high rigidity benefits.
Innovation Solution
A silent chain with inner and outer links of varying pitches and a chainring design featuring sloping sewage discharge grooves and tooth crown portions that enhance stability and reduce noise, combining the advantages of chain and belt drive transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional chains use inner links and outer links with the same pitch to engage the chainring, then the chain structure is simple and easy to manufacture, but the design flexibility of chain plates is limited
Solution Approach 1:
The chain is divided into inner links and outer links with different pitch values. The inner links have a first pitch while the outer links have a second pitch different from the first pitch, allowing independent design optimization for each link type while maintaining overall chain functionality
Solution Approach 2:
Different parts of the chain (inner links vs outer links) are given different local properties by assigning different pitch values to each. This allows the inner links to be optimized for one function while outer links are optimized for another, increasing overall design flexibility without compromising manufacturing simplicity
2Object-affected harmful factors
If belt drive transmission is used, then vibration noise is reduced and maintenance is minimized, but rigidity is lower and assembly is more complex
Solution Approach 1:
The patent merges the advantages of belt drive transmission (low noise, low vibration) with chain drive transmission (high rigidity, simple assembly) by creating a silent chain that combines features of both systems. The silent chain structure eliminates the noise and vibration of conventional chains while maintaining their rigidity and assembly simplicity
3Ease of operation
If conventional chain design is used, then assembly is simple and rigidity is high, but noise and vibration are higher compared to belt drive
Solution Approach 1:
The silent chain combines the quiet operation of belt drives with the easy assembly and high rigidity of chain drives. The toothed structure engages with the chainring similarly to conventional chains for easy assembly, while the silent chain plates reduce noise and vibration during operation
Data Source
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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 plate unit (51), and an inner chain body (52) that is fixedly disposed on an outer side of the inner plate unit (51) and that has an engagement protrusion (522). 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)