Tensioner Pin Support Wall Thickness Variation
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Solution Overview
Problem
Conventional tensioners experience stress concentration and durability degradation due to thickness differences in outer circumferential and pin support walls, leading to increased weight and required engine space, especially with protruding stopper levers.
Innovation Solution
The tensioner design features pin support walls with reduced thickness, where at least one outer side surface is formed on the inner side of the outer circumferential wall portions, dispersing stresses and reducing weight, and the stopper lever's protrusion is minimized to reduce necessary space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the pin support walls are made thick to support the ratchet pin and withstand stresses, then the strength and reliability are improved, but the weight of the tensioner body increases
Solution Approach 1:
The pin support walls are designed with non-uniform thickness, having greater thickness at the locations where they support the ratchet pin to withstand stresses, and reduced thickness in other areas. This local variation in thickness provides the necessary strength at critical locations while minimizing the overall weight of the tensioner body.
2Reliability
If the pin support walls are made thick to ensure durability, then the reliability is improved, but the manufacturing complexity increases due to varying wall thicknesses
Solution Approach 1:
The tensioner body incorporates pin support walls with locally varied thickness, where the walls are thicker at critical stress points to ensure durability and reliability, and thinner in non-critical areas. This design achieves high reliability while maintaining reasonable manufacturability by concentrating material only where structurally necessary.
3Ease of operation
If the stopper lever protrudes beyond the outer circumferential wall to function properly, then the ease of operation is improved, but the volume of the tensioner assembly increases
Solution Approach 1:
The stopper lever is designed to be positioned within or integrated with the outer circumferential wall structure of the tensioner body, rather than protruding significantly beyond it. This nesting approach allows the stopper lever to perform its function of restraining the plunger while minimizing the overall volume of the tensioner assembly and reducing interference with surrounding engine components.
Data Source
AI summary
Provided is a tensioner in which the durability of the tensioner body is increased, the tensioner body is reduced in weight, and the arrangement space is reduced. A tensioner 100 includes a tensioner body 110, a plunger 120, and a ratchet 130. The tensioner body 110 has a hole outer circumferential wall 112 and a pair of pin support walls 116, 117. The hole outer circumferential wall 112 has a pair of outer circumferential wall portions 113, 114 crossing a virtual line L extending in the pin longitudinal direction through the center of the plunger housing hole 111. At least one of the outer side surfaces of the pair of pin support walls 116, 117 is formed on the inner side, in the pin longitudinal direction, of the outer side surface of one of the outer circumferential wall portions 113, 114.