Pivoting Chain Guide Structure for Vibration and Noise Isolation
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Solution Overview
Problem
Conventional chain guides transmit noise and vibration from the running chain to the engine due to high-rigidity components that facilitate vibration transmission from the chain running surface to the engine block via the pivot shaft.
Innovation Solution
A chain guide configuration with a guide shoe and pivotable guide body, featuring a support wall with a curved base part and a connecting portion that reduces cross-sectional area towards the boss part, eliminating direct contact between the running surface-side rib and the boss part, and incorporating rib plates to enhance rigidity without forming high-rigidity vibration transmission paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a high-rigidity structure is provided in the portion extending from the chain running surface to the boss part, then the strength and rigidity of the guide body is improved, but vibration and noise are easily transmitted to the engine block
Solution Approach 1:
The patent applies local quality by providing different structural characteristics in different regions of the guide body. The base part has a curved upper surface that forms a space with the boss part, creating a local low-rigidity zone for vibration absorption, while the support wall and other regions maintain adequate rigidity for structural support. This localized differentiation allows the structure to simultaneously achieve strength and vibration reduction.
Solution Approach 2:
The curved base part acts as an intermediary element between the chain running surface and the boss part. By forming a space between these components, the curved base part serves as a vibration-absorbing mediator that interrupts the direct transmission path of vibrations to the engine block, while still maintaining the structural integrity needed for strength.
2Stability of the object's composition
If connecting parts with larger width than support wall thickness are provided, then the rigidity against pivoting force is improved, but vibration transmission paths are created
Solution Approach 1:
The patent avoids providing connecting parts with larger width than support wall thickness in the critical region between the running surface-side rib and the boss part. Instead, the connecting portion maintains a width equal to or less than the support wall thickness, creating a local low-rigidity zone that prevents vibration transmission while still providing sufficient structural connection for stability.
3Strength
If the running surface-side rib is directly connected to the boss part, then structural strength is improved, but vibration from chain entrance is transmitted to the engine block
Solution Approach 1:
The curved base part serves as an intermediary element that prevents direct connection between the running surface-side rib and the boss part. This intermediary structure absorbs vibrations from chain entrance before they can be transmitted to the boss part and engine block, while still maintaining adequate structural strength through its curved geometry and integration with the support wall.
Solution Approach 2:
The patent converts the potential harm of direct rigid connection (vibration transmission) into a benefit by using the curved base part to absorb and dissipate vibration energy. The space formed by the curved base part transforms what would be a vibration transmission path into a vibration-absorbing zone, turning the structural connection into a vibration-dampening feature.
Data Source
AI summary
An object of the present invention is to provide a chain guide that can reduce vibration and noise while maintaining necessary strength, rigidity, and durability. The chain guide has a support wall extending forward from a boss part, which constitutes a circumferential wall of a pivot shaft, along a plane perpendicular to a pivot axis line. The support wall includes a base part that is provided with a running surface-side rib, and a connecting portion with a cross-sectional area thereof reducing toward the boss part. The running surface-side rib is not in contact with the boss part. The chain guide does not include a connecting portion that has a larger width than the thickness of the support wall and extends in a pivoting direction on a back side of the running surface-side rib in a region at a pivot shaft side end thereof.