Chain Guide Reinforcing Rib Segmentation for Stress Reduction
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Solution Overview
Problem
Conventional chain guides face challenges in achieving weight reduction and cost efficiency while maintaining durability and rigidity, and they can cause internal stress concentration and production defects due to reinforcing ribs.
Innovation Solution
A chain guide design featuring a body part with a support wall and laterally protruding reinforcing ribs, including an independent zone that is not connected to other parts over a significant length, which reduces stress concentration and allows for smoother resin flow during production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the thickness of the support wall or reinforcing ribs is increased, then the rigidity and durability of the chain guide is improved, but the weight and material cost increase
Solution Approach 1:
The reinforcing rib is divided into multiple ribs (first, second, third, and fourth reinforcing ribs) positioned at different locations around the support wall. This segmentation allows the structure to achieve the required rigidity through distributed reinforcement rather than increasing the thickness of individual ribs or the support wall, thereby avoiding unnecessary weight increase.
2Strength
If reinforcing ribs are added to enhance strength, then the overall rigidity is improved, but internal stress concentration occurs at the lower end portions of the ribs
Solution Approach 1:
The reinforcing ribs are positioned at specific locations (first and second ribs at one end, third and fourth ribs at the other end) rather than uniformly distributed. This local quality approach concentrates reinforcement where needed while avoiding stress concentration at rib lower ends, as the ribs are strategically placed to distribute loads more evenly across the support wall.
3Strength
If the number or thickness of reinforcing ribs is increased, then the structural strength is improved, but resin flow during injection molding is obstructed, causing defects and dimensional errors
Solution Approach 1:
Instead of using fewer thick ribs, the design employs multiple thinner ribs (four reinforcing ribs total) distributed around the support wall. This segmentation allows resin to flow more easily during injection molding compared to having fewer, thicker ribs, while still achieving the required structural strength through the combined effect of multiple reinforcement elements.
Data Source
AI summary
A chain guide is provided which has a simple structure and improved durability, and which enables reduction in weight and in material cost, and moreover which does not inhibit smooth flow of resin inside a metal mold, and with which dimension errors, contour errors, internal distortion, defects and the like are reduced and concentration of internal stresses or repeatedly applied bending stresses can be prevented. A reinforcing rib of a body part includes a lateral rib that has an independent zone not connected to other parts of the reinforcing rib over a length of 20% or more of a distance between support portions at two locations of the rib. The independent zone is provided on a side further away from a guide surface than a midpoint of the height of the support wall.