Dynamic Pivot Dual Arm Tensioner for Belt Slip and Vibration
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Solution Overview
Problem
Existing dual arm tensioners face challenges in optimizing belt tension under varying engine modes, leading to issues such as non-optimal wrap angles, high vibration, belt slip, and varying hubload forces, which are typically addressed by compromising performance through suboptimal pivot placement.
Innovation Solution
A dual arm tensioner with a dynamic pivot and variable thickness bushing, featuring a stationary and dynamic pivot center, optimizes belt tension by dynamically adjusting the pivot position based on engine modes, minimizing belt slip and vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed pivot location is used in dual arm tensioners, then the structure is simple and easy to manufacture, but optimal belt tension cannot be maintained under varying engine modes
Solution Approach 1:
The patent applies the dynamics principle by replacing the fixed pivot with a dynamic pivot that moves along an arcuate path. This allows the tensioner arms to maintain optimal geometric relationships with the pulleys under varying engine modes (starter, generator, braking, etc.), dynamically adjusting the belt tension to maximize wrap angles and minimize slip without requiring complex active control systems
2Adaptability or versatility
If the pivot location is optimized for one engine mode, then belt tension is optimal for that mode, but performance is compromised for other modes
Solution Approach 1:
The dynamic pivot mechanism enables the tensioner to adapt to multiple engine modes by allowing the pivot point to traverse an arcuate path. This geometric flexibility ensures that optimal wrap angles and belt tensions are maintained across starter, generator, braking, and other operational modes, eliminating the need to compromise performance for a single mode
3Device complexity
If suboptimal pivot placement is used to accommodate all engine modes, then the structure remains simple, but issues such as small wrap angles, high vibration, and belt slip occur
Solution Approach 1:
The dynamic pivot eliminates harmful effects like vibration and belt slip by enabling the tensioner to maintain optimal geometric relationships with the pulleys under all engine modes. The arcuate movement of the pivot ensures maximum wrap angles are achieved, preventing belt slip and reducing vibrations without requiring additional damping components or complex active control systems
Solution Approach 2:
The patent changes the positional parameter of the pivot point from fixed to variable, allowing it to traverse an arcuate path. This parameter change enables the tensioner to optimize wrap angles and belt tension dynamically, eliminating harmful effects like vibration and slip while maintaining structural simplicity
Data Source
AI summary
To obtain maximum performance and belt longevity, it is important that the belt is properly tensioned. In some scenarios such as hybrid vehicles where the belt is going through large variations in drive torque due to varying Belt Starter Generator (BSG) parameters due to regeneration and the like, a dynamic pivot may optimize belt tension for a variety of engine modes. In some embodiments a dynamic pivot dual arm tensioner may include a center arm having a first tensioning pulley journaled to the center arm and engageable with a mounting surface, such as an engine block or accessory bracket, through a mounting axis; a side arm having a second tensioning pulley journaled to the side arm and coupled to the center arm; a dynamic pivot around which the tensioner dynamically rotates; and the dynamic pivot journaled to the center arm.