Disk Spring Tensioner Arm for High Spring Rate in Compact Space
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Solution Overview
Problem
Dual hydraulic variable force tensioner systems face limitations in achieving high spring rates with minimal secondary piston extension, which affects the control and efficiency of chain drive systems, particularly under varying mechanical loads and wear conditions.
Innovation Solution
A stack of disk springs, specifically Belleville springs, is placed between the second piston and the hydraulic tensioner arm, allowing for adjustable spring rates by varying the number and orientation of springs, enabling higher stiffness and reduced package space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a coil spring is used in the tensioner arm, then the spring force can be adjusted, but the spring rate is significantly higher than desired and requires large secondary piston extension
Solution Approach 1:
The patent changes the physical parameters of the spring system by replacing a coil spring with disk springs (Belleville springs), which have different geometric and mechanical properties. This allows achieving the required spring force with a much higher spring rate while requiring minimal secondary piston extension, directly resolving the contradiction between force output and piston travel distance
2Force
If a high spring rate is achieved with a coil spring, then increased force is provided, but the package space increases due to required piston extension
Solution Approach 1:
The patent changes the spring type from coil spring to disk spring, fundamentally altering the space-force relationship. Disk springs achieve high spring rates in a compact configuration, reducing the package space required while maintaining or increasing the spring force output capability
Solution Approach 2:
The patent transitions from a linear coil spring geometry to a stacked disk spring configuration, utilizing the stacking dimension to achieve high spring rates. Multiple disk springs can be stacked in series or parallel to precisely control the spring rate while maintaining a compact overall package volume
3Force
If multiple coil springs are stacked to achieve desired spring rate, then the spring force can be optimized, but the device complexity and package space increase
Solution Approach 1:
The patent changes from using multiple coil springs to using disk springs, which inherently provide higher spring rates in a more compact and simpler configuration. The disk spring geometry naturally achieves the desired spring rate characteristics without requiring complex stacking arrangements of multiple coil springs
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 allows for higher spring rates and improved dynamic load sharing, maintaining optimal chain or belt tension with reduced noise and increased drive efficiency across different operational conditions.
Implementation Method 1
A stack of disk springs, specifically Belleville springs, is placed between the second piston and the hydraulic tensioner arm
Data Source
AI summary
A stack of disk springs are placed between a second piston of a dual hydraulic variable force tensioner system and a hydraulic tensioner arm to allow much higher spring rates if desired. The springs may be stacked in multiple configurations to provide different spring rates. Package space can be reduced depending on the number of springs and orientations of said springs within the tensioner arm.