Chain Tensioner With Sub-Arm Linkage
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Solution Overview
Problem
Existing chain tensioner devices face challenges in maintaining stable tension and power transmission performance due to limited extension and contraction response of the plunger, which struggles to follow rapid changes in chain tension, leading to reduced durability and increased plunger stroke.
Innovation Solution
A chain tensioner device with a main arm and sub-arm configuration, where the first and second slide surfaces on the main and sub-arms respectively, enhance the stroke of the tensioner lifter, allowing for increased transfer of biasing force to the main arm, thereby maintaining stable chain tension and reducing the load on the tensioner lifter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the stroke of the plunger is increased to ensure the stroke of the tensioner arm, then the tensioner arm can maintain stable tension, but the extension and contraction response of the plunger decreases
Solution Approach 1:
The patent introduces a sub-arm that converts the linear motion of the plunger into a rotational motion about a fulcrum, and then into the linear motion of the main arm. This dimensional transformation allows the plunger to have a short stroke while the main arm achieves a larger effective stroke through the lever action of the sub-arm.
Solution Approach 2:
The sub-arm acts as an intermediary mechanism between the plunger and the main arm. It transfers and transforms the motion from the plunger to the main arm, enabling the decoupling of the plunger stroke length from the main arm stroke length while maintaining responsive motion transmission.
2Speed
If the stroke of the plunger is reduced to increase extension and contraction response, then the response speed improves, but the stroke of the tensioner arm becomes insufficient
Solution Approach 1:
By introducing the rotational dimension through the sub-arm's rotation about its fulcrum, the system amplifies the effective stroke of the main arm without increasing the plunger stroke. The rotational motion of the sub-arm converts small linear displacements of the plunger into larger linear displacements at the main arm.
Solution Approach 2:
The sub-arm serves as a motion-amplifying intermediary that receives motion from the plunger and delivers amplified motion to the main arm, allowing the plunger to maintain short stroke for fast response while the main arm achieves sufficient stroke for stable tensioning.
3Device complexity
If a direct connection between the plunger and main arm is used, then the structure is simple, but the plunger must have large stroke which reduces response and increases size
Solution Approach 1:
The patent segments the direct connection between plunger and main arm into two separate linkage paths: one through the sub-arm (for motion transformation) and another through the main arm (for force transmission). This segmentation allows each component to be optimized for its specific function while maintaining overall structural efficiency.
Solution Approach 2:
The sub-arm is introduced as an intermediary linkage that enables the plunger to have reduced stroke while still providing sufficient motion to the main arm, thereby improving response speed without requiring a completely complex multi-component system.
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 configuration enhances the extension and contraction response of the plunger, improving power transmission performance and durability by allowing the tensioner lifter to maintain stable chain tension even with significant changes in chain tension, while reducing the size and load on the tensioner lifter.
Implementation Method 1
a first slide surface provided on the main arm and a second slide surface provided on the sub-arm slidably abut against each other
Data Source
AI summary
A chain tensioner device having a first slide surface of a main arm pivotably supported at an upper end thereof, and a second slide surface of a sub-arm pivotably supported at a lower end thereof. The first and second slide surfaces slidably abut against each other. When the main arm is biased toward a timing chain via the sub-arm by a biasing force of a plunger of a tensioner lifter, a stroke of the main arm is increased with respect to a stroke of the plunger.