Chain Guide Structure for Thermal Expansion and Sliding Engagement
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Solution Overview
Problem
Chain guides with integrally formed guide shoes and base members experience restricted movement and potential breakage due to thermal expansion and contraction differences, especially in large guides with significant temperature changes, leading to durability issues and deformation during molding.
Innovation Solution
A chain guide design with a guide shoe and base member united by two-material molding, featuring a fixed and movable engaging part, where the molding gate mark is positioned near the fixed engaging part to prevent welding and ensure movement, and a base groove with chamfered edges to dissipate heat and prevent melting, allowing for thermal expansion without restricting the guide shoe's movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the guide shoe and base member are integrally formed by two-material molding, then assembly complexity is reduced and manufacturing efficiency is improved, but thermal expansion differences cause the guide shoe to be restricted in movement and may lead to breakage
Solution Approach 1:
The engaging part is divided into a fixed engaging part and a movable engaging part. The fixed engaging part restricts movement in directions perpendicular to the longitudinal guiding direction, while the movable engaging part allows thermal expansion and contraction along the longitudinal guiding direction. This segmentation resolves the contradiction by providing both structural integration benefits and thermal movement freedom.
Solution Approach 2:
Different regions of the engaging part have different functional properties. The fixed engaging part provides rigid constraint for positional stability, while the movable engaging part provides flexibility for thermal expansion. This local differentiation of functional properties allows the integral structure to simultaneously achieve assembly simplicity and thermal movement freedom.
2Productivity
If the guide shoe and base member are integrally formed by two-material molding, then manufacturing efficiency is improved, but the guide shoe may break due to thermal stress from expansion and contraction differences
Solution Approach 1:
The engaging part is segmented into fixed and movable portions that differentially constrain thermal expansion. This allows the integral structure to accommodate thermal stress without breaking, maintaining durability while preserving manufacturing efficiency benefits.
Solution Approach 2:
The constraint parameters are changed by providing different degrees of freedom in different directions. The fixed engaging part maintains strict positional parameters perpendicular to the guiding direction, while the movable engaging part allows parameter variation along the longitudinal direction to accommodate thermal expansion, preventing breakage.
3Manufacturing precision
If the base groove width is reduced due to deformation during molding, then the guide shoe movement is restricted and may lead to breakage, but maintaining groove width requires additional molding controls
Solution Approach 1:
The engaging part is segmented into fixed and movable portions. The movable engaging part is specifically designed to accommodate variations in base groove width caused by molding deformation, allowing the guide shoe to maintain movement capability even when groove width varies, thus preventing breakage without requiring strict groove width control.
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
The design eliminates the need for assembly, enhances durability by preventing guide shoe breakage from thermal stress and deformation, and ensures reliable performance across varying temperatures, particularly in harsh environments with large temperature fluctuations.
Implementation Method 1
the guide shoe expands and contracts in a longitudinal guiding direction relative to the base member due to a difference in thermal expansion and contraction in the longitudinal guiding direction between the base member and the guide shoe, which depends on the temperature of the environment in which the chain guide is used
Implementation Method 2
the primary material that is to become the base member may melt due to the heat during the molding of the guide shoe from the secondary material, and the guide shoe and the base member may be welded to each other
Data Source
AI summary
An object of the present invention is to provide a chain guide that eliminates the burden of assembling a guide shoe and a base member together, and prevents the guide shoe from being limited in its movement in the longitudinal guiding direction relative to the base member to improve durability. The guide shoe and the base member of the chain guide according to the invention are united by being integrally molded. The chain guide includes a fixed engaging part where the guide shoe engages with the base member such that the guide shoe is restricted from moving in the longitudinal guiding direction relative to the base member, and a movable engaging part where the guide shoe engages with the base member such that the guide shoe is slidable relative to the base member. A molding gate mark is positioned at or near the fixed engaging part.