Conical Torsion Spring Timing Belt Tensioner With Integrated Damping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing tensioners are often bulky and require manual assembly due to spring entanglement issues, lacking effective damping mechanisms, and have rapid spring rate changes that can lead to shock loading.
Innovation Solution
A compact tensioner design with a shaft-and-base unit, a tensioner arm, pulley, and a damping carrier that includes a conical torsion spring with inhibited entanglement, automated assembly features, and progressive locking, along with integrated damping to manage sudden belt tension changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a conventional tensioner design is used, then the tensioner can maintain belt tension, but the tensioner becomes bulky and requires manual assembly due to spring entanglement issues
Solution Approach 1:
The tensioner is divided into modular components including a shaft-and-base unit, tensioner arm assembly, pulley, and spring assembly. Each component can be manufactured and assembled separately, eliminating spring entanglement issues during assembly while reducing overall tensioner volume through compact integration of segmented parts.
2Reliability
If damping mechanisms are added to prevent shock loading, then the tensioner can resist sudden belt tension changes, but the device complexity increases
Solution Approach 1:
The damping mechanism is merged with the existing tensioner arm and shaft-and-base unit. The shaft-and-base unit serves dual functions as both a mounting structure and a damping element through its friction-based shock absorption capability. This integration provides shock resistance without adding separate damping components, thereby avoiding increased device complexity.
3Speed
If the spring rate changes rapidly under belt tension, then the spring can respond to tension changes, but shock loading occurs
Solution Approach 1:
The shaft-and-base unit incorporates friction-based damping that activates beforehand to cushion sudden tension changes. This friction damping mechanism is built into the shaft-and-base unit structure, providing progressive resistance that prevents shock loading while maintaining rapid spring response capability through controlled energy dissipation.
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
The design achieves a more compact tensioner with reduced manual labor, minimizes spring entanglement, and provides controlled damping to prevent shock loading, enhancing operational reliability and efficiency.
Implementation Method 1
a spring that acts between the base and the arm to drive the arm into the belt
Implementation Method 2
The direction into the belt (i.e. the direction in which the spring drives the arm) may be referred to as a direction towards a free arm position (i.e. towards a position that the tensioner arm would reach if no belt were present to stop it). This is a direction of lessening spring potential energy.
Implementation Method 3
it is desirable to provide damping on a tensioner in order to assist the tensioner arm in resisting being thrown off a belt (e.g. a timing belt) during sudden increases in belt tension
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A tensioner for an endless drive member, comprising: a shaft-and-base unit that is mountable to be stationary relative to an engine block; a tensioner arm that is pivotable relative to the shaft-and-base unit about a tensioner arm axis; a pulley that is rotatably mounted to the tensioner arm for rotation about a pulley axis that is offset from the tensioner arm axis, wherein the pulley is engageable with an endless drive member, wherein the pulley has a swept volume; and a tensioner spring that is positioned to urge the tensioner arm in a first direction about the tensioner arm axis, wherein the tensioner spring is a torsion spring having a first spring end and a second spring end and a plurality of coils between the first and second spring ends, wherein the plurality of coils decrease in diameter from one of the first and second spring ends to the other of the first and second spring ends, wherein one of the first and second spring ends is positioned to transfer torque into the shaft-and-base unit and the other of the first and second spring ends is positioned to transfer torque into the tensioner arm, wherein the tensioner spring is positioned substantially entirely within the swept volume of the pulley.