Accessory Drive Tensioner Layout for Reactive Belt Tension Control
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Solution Overview
Problem
Conventional accessory drive tensioners are not optimized for reactivity to sudden tension changes, particularly during transitions between different operating modes of reversible electric machines, and fail to compensate for belt elongation over time without losing reactivity.
Innovation Solution
A tensioner design featuring a support element, an intermediate rotating element, and a rigid tensioner element with pulleys, where the intermediate element rotates about a first axis and the tensioner element rotates about a second axis, allowing for high reactivity to tension variations and belt elongation compensation through a spring mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional tensioners are used in reversible electric machine drives, then the structure is simple, but the reactivity to sudden tension changes during mode transitions is insufficient
Solution Approach 1:
The tensioner is divided into two independent pulleys (first pulley and second pulley) that can move relative to each other, rather than a single rigid structure. This segmentation allows each pulley to independently respond to tension changes on different belt branches, improving reactivity while maintaining manageable structural complexity through modular design
Solution Approach 2:
The tensioner employs dynamic elements including a movable second pulley that can translate along a straight line relative to the first pulley, and a spring mechanism that dynamically adjusts tension. This dynamic configuration enables rapid response to sudden tension changes during electric machine mode transitions, significantly improving reactivity compared to static conventional tensioners
2Reliability
If the tensioner maintains high reactivity through rigid structures, then response to tension changes is fast, but compensation for belt elongation over time is lost
Solution Approach 1:
The spring mechanism allows the tensioner to adaptively change the positional parameters of the pulleys over time. As the belt elongates during operation, the spring gradually adjusts the pulley positions to maintain optimal belt tension, enabling long-term reliability without losing the inherent reactivity of the rigid pulley structures to sudden tension changes
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 ensures high reactivity to sudden tension changes and compensates for belt elongation over time, maintaining optimal belt tension across different operating modes of the electric machine.
Implementation Method 1
a spring acting between the support element and the intermediate element so as to push the pulleys into contact with the belt
Data Source
Figure 1~4
Figure 5~6
Figure 7~8
AI summary
Tensioner for an accessory drive (1) of a motor vehicle comprising a support element (11) adapted to be fixed on an electric machine (6), an intermediate element (12) carried by the support element (11) and rotating with respect thereto about a first fixed axis (A), a rigid tensioner element (13) rotating with respect to the intermediate element (12) about a second axis (B) parallel to the first axis (A), a pair of tensioner pulleys (14, 15) carried by the tensioner element (13) and adapted to cooperate with respective branches (9a, 9b) of an endless drive element (9) of the drive (1) positioned on opposite sides with respect to the electric machine (6), and a spring (16) acting between the support element (11) and the intermediate element (12) to push the tensioner pulleys (14, 15) into contact with the endless drive element (9).