Chain Tensioner Pin-Hole Layout for Safer Lever Retention
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Solution Overview
Problem
Existing chain tensioners face issues with component deformation or breakage during transport and incorrect assembly due to the guide lever hitting the plunger, and the stopper pin used for retention experiences high friction and potential bending, making it difficult to remove and potentially scratching the plunger surface.
Innovation Solution
A chain tensioner design where the guide lever is integrated with the tensioner body, using a stopper pin that passes through body-side and lever-side fixing pin holes without extending through the plunger, ensuring both the plunger and guide lever are retained, preventing deformation and breakage, and allowing for easier assembly and increased design flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stopper pin is used to retain the plunger in a compressed state, then the plunger can be retained, but the stopper pin receives large bending stress and generates large friction resistance, making it difficult to pull out and potentially scratching the plunger surface
Solution Approach 1:
The retention function is segmented between two components: the stopper pin retains the plunger in the compressed state, while the retaining ring retains the stopper pin itself. This segmentation allows the stopper pin to be easily removable by simply withdrawing it from the retaining ring, without requiring forceful extraction that would cause bending stress or friction damage to the plunger.
Solution Approach 2:
The retaining ring acts as an intermediary component between the stopper pin and the plunger assembly. It provides a dedicated retention mechanism for the stopper pin, allowing the stopper pin to be easily installed and removed without directly interacting with the plunger during the retention/release process, thereby reducing friction resistance and bending stress.
2Ease of operation
If the guide lever is supported pivotably on the arm part using a through hole and shaft member structure, then the guide lever can pivot, but a large number of components and process steps are required for assembly
Solution Approach 1:
The arm part and guide lever are merged into a single integrated component, eliminating the need for separate shaft members and multiple fastening components. The pivotable connection is achieved through integrated structural features (such as pivot holes and pins formed as part of the monoblock structure), reducing the number of components and simplifying the assembly process while maintaining the guide lever's pivoting functionality.
Solution Approach 2:
The integrated arm part-guide lever structure performs multiple functions: it provides the pivotable connection for the guide lever, maintains the correct tension in the chain, and eliminates the need for separate retention components. This multi-functional design reduces overall device complexity while preserving all necessary operational capabilities.
3Reliability
If the stopper pin is used to retain both the plunger and guide lever, then both components can be retained, but the stopper pin experiences high bending stress and friction, making it difficult to remove
Solution Approach 1:
The retention function is divided between two separate components: the stopper pin retains the plunger, while the retaining ring retains both the stopper pin and guide lever. This segmentation distributes the mechanical stresses, preventing the stopper pin from experiencing excessive bending stress while maintaining reliable retention of all components.
Solution Approach 2:
The retaining ring serves as an intermediary structure that provides a dedicated retention mechanism for the stopper pin and guide lever assembly. It absorbs and distributes the retention forces, reducing the bending stress on the stopper pin and preventing direct conflict between the stopper pin's retention function and its removability requirement.
Data Source
AI summary
An object of the present invention is to provide a chain tensioner that can prevent breakage or deformation of its components during transport or storage, prevent wrong assembly, and increase the degree of design freedom. The chain tensioner includes a guide lever supported pivotably on an arm part that is provided to a tensioner body. The tensioner body has a body-side fixing pin hole positioned for a stopper pin to pass through without extending through the plunger. The guide lever has a lever-side fixing pin hole that comes to be coaxial with the body-side fixing pin hole in a predetermined pivoting position.