Arc-Shaped Recess Slippage Prevention for Timing Chain
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Solution Overview
Problem
The existing slippage prevention rail in internal combustion engines interferes with auxiliary sprockets and signal plates when the chain case is fitted or removed, causing operational and maintenance issues.
Innovation Solution
A slippage prevention mechanism with an arc-shaped recess is integrated into the cylinder block, allowing for a predetermined clearance between the timing chain and drive sprocket, preventing lubricant scattering while avoiding interference with other components by offsetting the chain tensioner and slippage prevention rail.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a slippage prevention rail is provided to prevent timing chain slippage, then timing chain slippage is prevented, but interference with auxiliary sprockets and signal plates occurs during installation and maintenance
Solution Approach 1:
The slippage prevention function is extracted from a traditional rail structure and reimplemented through a groove formed directly in the cylinder block. This removes the interfering rail component while preserving the slippage prevention capability through the groove's geometric constraint on the timing chain.
Solution Approach 2:
The slippage prevention function is merged with the cylinder block structure itself by forming a groove directly in the block. This integration eliminates the need for a separate rail component that would interfere with auxiliary sprockets and signal plates during installation and maintenance.
2Reliability
If a slippage prevention rail projects from the chain case, then lubricant supply to the tension rail is ensured, but interference with auxiliary sprockets and signal plates occurs
Solution Approach 1:
The slippage prevention groove is merged with the cylinder block structure, eliminating the need for a separate projecting rail from the chain case. This integration maintains the lubricant supply function while simplifying the overall chain case structure and removing interference issues.
Solution Approach 2:
The slippage prevention function is extracted from the chain case structure and relocated to the cylinder block. This removes the interfering projecting rail while preserving the essential functions of lubricant supply and wear prevention through the groove geometry.
3Reliability
If the chain case is fitted tightly to prevent slippage, then timing chain containment is improved, but accessibility for maintenance is reduced
Solution Approach 1:
The slippage prevention function is extracted from a chain case projecting rail and relocated to a groove in the cylinder block. This allows the chain case to be fitted tightly for maintenance while the groove continues to prevent timing chain slippage independently.
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 ensures effective slippage prevention without interfering with auxiliary sprockets or signal plates, maintaining proper lubrication and reducing wear on components, while facilitating easier maintenance and installation.
Implementation Method 1
preventing lubricant scattering while avoiding interference with other components
Data Source
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AI summary
A sprocket (3A, 3B) is fixed onto a crank shaft (2) projecting outward from a cylinder block (1) of an internal combustion engine (100). A timing chain (7A, 7B) is looped around the sprocket (3A, 3B). A slippage prevention mechanism (10) which prevents slippage of the timing chain (7A, 7B) with respect to the sprocket (3A, 3B) comprises an arm (10C) extending from a base portion (10A) fixed to the cylinder block. A slippage prevention rail (10B) in the form of an arc-shaped recess is formed on the arm (10C) so as to face the engaging part between the sprocket (3A, 3B) and the timing chain (7A, 7B) with a clearance smaller than the height of a tooth of the sprocket (3A, 3B) therebetween. The slippage prevention rail (10B) thus constructed does not interfere with other members fixed onto the crank shaft (2).