Nested Torsion Spring Tensioner for Low-Height Belt Drives
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Solution Overview
Problem
Existing tensioners are constrained in size due to the axial arrangement of components, limiting the minimum height and affecting engine and belt system design, particularly in applications where synchronization between the camshaft and crankshaft is critical and oil presence is a factor.
Innovation Solution
A tensioner design featuring a torsion spring disposed within a radially inward receiving portion of a base cylindrical portion, allowing for a concentric and nested arrangement of components that minimizes height while maintaining effective belt tensioning in oil environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a torsion spring is stacked axially with a pulley bearing, then the tensioner can provide belt tensioning force, but the minimum height of the device increases
Solution Approach 1:
The torsion spring is nested within the base cylindrical portion, specifically utilizing the radially inward receiving portion. This nesting arrangement allows the spring to be contained within the existing base structure rather than requiring additional axial space, thereby reducing the overall height of the tensioner while maintaining the necessary tensioning force.
Solution Approach 2:
The invention transitions from an axial arrangement (stacking components along the axis) to a radial arrangement (positioning the torsion spring within the radially inward receiving portion of the base). This dimensional change allows the spring to provide tensioning force without increasing the axial height of the device.
2Length of stationary object
If the tensioner height is reduced for compact design, then the device can be used in cramped applications, but the belt tensioning effectiveness may be compromised
Solution Approach 1:
By nesting the torsion spring within the base cylindrical portion's radially inward receiving portion, the design achieves compact dimensions suitable for cramped applications while preserving the spring's mechanical properties and tensioning effectiveness.
Solution Approach 2:
The torsion spring is pre-loaded within the base structure to provide initial tensioning force. This preliminary action ensures that the belt maintains proper tension without requiring additional axial space, thereby maintaining reliability in a compact configuration.
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 design enables compact tensioner construction that maintains synchronization between the camshaft and crankshaft, preventing catastrophic engine damage by ensuring proper belt tensioning, even in oil environments, and allows for use in cramped applications.
Implementation Method 1
a torsion spring disposed within the radially inward receiving portion, the torsion spring applying a biasing force to the eccentric arm
Data Source
AI summary
A tensioner comprising a base having a cylindrical portion extending axially, the cylindrical portion comprising a radially outer surface and a receiving portion that is radially inward of the radially outer surface, an eccentric arm pivotally engaged with the radially outer surface, a torsion spring disposed within the radially inward receiving portion, the torsion spring applying a biasing force to the eccentric arm, and a pulley journalled to the eccentric arm.