Dual Pivot Arm Tensioner for Alternator Starter Systems
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Solution Overview
Problem
Belt drive systems with alternator starter (BAS) systems require a unique tensioner arrangement due to the alternator acting as both a load and power provider, leading to extreme movement of traditional tensioners and necessitating a second tensioner, resulting in an expensive solution with excessively long belts.
Innovation Solution
A tensioner assembly with a first and second pivot arm mounted to a base, featuring a flexible member trained between them for coordinated movement, and a tensioner assembly on the base engaging the flexible member, allowing synchronized and coordinated rotation to maintain proper belt tension without the need for a second tensioner.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional tensioner is positioned on the slack side span of a belt drive in a BAS system, then the tensioner can maintain minimum belt tension during normal operation, but the alternator acting as a power provider during starting creates extreme movement of the tensioner and transforms the slack span location
Solution Approach 1:
The tensioner is divided into two separate pivot arms (first pivot arm and second pivot arm) that can move independently relative to each other. Each pivot arm is positioned to engage a different belt span, allowing them to respond independently to tension variations in their respective spans without interfering with each other's movement.
Solution Approach 2:
Two tensioner functions are merged into a single device by combining the first pivot arm with the second pivot arm through a common mounting base. The flexible member connects both pivot arms, allowing them to work together as an integrated system while maintaining independent functionality for different belt spans.
2Reliability
If a second tensioner is added to handle the new slack side span location during alternator starting, then proper belt tension can be maintained in all operational modes, but the solution becomes expensive and requires excessively long belts
Solution Approach 1:
The single tensioner device performs multiple functions by having two pivot arms that can each engage different belt spans depending on operational mode. During normal operation, one pivot arm maintains tension on the traditional slack side span. During alternator starting, the other pivot arm engages the new slack side span, allowing the device to adapt to different operational requirements without requiring separate tensioners.
Solution Approach 2:
The tensioner employs dynamic positioning capabilities where the first and second pivot arms can rotate independently to different positions based on operational conditions. This dynamic adjustment allows the tensioner to automatically adapt to changing belt tension requirements during alternator starting versus normal operation, eliminating the need for fixed secondary tensioners.
3Reliability
If two tensioners are used in a BAS system to accommodate the changing slack span location, then proper belt tension is maintained, but the belt length must be excessively long to accommodate the multiple tensioners
Solution Approach 1:
The tensioner device segments the belt engagement by having two separate pivot arms that can independently engage different portions of the belt span. This segmentation allows effective tension control on both the traditional slack side span and the new slack side span location during alternator starting, eliminating the need for a second separate tensioner and its associated belt length requirements.
4Device complexity
If a traditional tensioner design is used, then the structure is simple, but it cannot handle the extreme movement caused by alternator starting without additional components
Solution Approach 1:
The tensioner structure is segmented into two independent pivot arms that can respond to different operational conditions. This segmentation provides the adaptability needed to handle both normal operation and alternator starting modes, while keeping each individual pivot arm relatively simple in structure.
Solution Approach 2:
Multiple functional capabilities are merged into a single tensioner device by combining two pivot arms with different engagement positions. This merging achieves operational versatility across different modes while maintaining a unified, space-efficient structure that doesn't require additional separate tensioner assemblies.
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 solution effectively maintains proper belt tension across varying operational modes, reducing the need for a second tensioner and minimizing belt length, thereby reducing costs and improving system efficiency.
Implementation Method 1
a flexible member trained between the first pivot arm and the second pivot arm so the pivot arms move in a coordinated manner
Data Source
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AI summary
A tensioner comprising a base, a first pivot arm pivotally engaged to the base, a first pulley journalled to the first pivot arm, a second pivot arm pivotally engaged to the base, a second pulley journalled to the second pivot arm, a flexible tensile member having a toothed engagement with the first pivot arm and a toothed engagement with the second pivot arm whereby the first pivot arm and the second pivot arm move in a coordinated manner, and a tensioner assembly pivotally engaged to the base and engaged with the flexible tensile member.