Belt Tensioning Arms With Variable Damping for Hybrid Drives
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Solution Overview
Problem
Belt tensioning devices in traction drives, particularly in hybrid vehicles with starter generators, face challenges in maintaining optimal belt tension and damping across varying operating conditions, leading to oscillations and vibrations due to differing belt forces during partial load, full load, starting, boost, and recuperation modes.
Innovation Solution
A belt tensioning device with a damping mechanism that generates varying damping torque based on the rotational position and direction of the tensioning arm relative to the base body, utilizing different coefficients of friction and spring arrangements to adapt damping to the operating state, ensuring minimal torque in normal operation and increased damping during starting and boost modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If constant damping is provided between the tensioning arms, then oscillations during normal operation are suppressed, but drag torque increases during starting and boost modes
Solution Approach 1:
The damping force is made variable rather than constant. The damping element's friction characteristic changes based on the operating state: low damping during normal operation to reduce drag torque, and high damping during starting/boost modes to suppress oscillations. This dynamic adaptation resolves the contradiction between stability and energy efficiency.
Solution Approach 2:
The damping parameter (friction force) is changed according to operating conditions. By varying the damping force between low and high states based on the belt tensioner's operational mode, the system achieves both low drag torque during normal operation and effective oscillation suppression during high-load modes.
2Reliability
If high damping force is provided to suppress oscillations, then belt tension stability improves, but fuel efficiency decreases due to increased drag torque
Solution Approach 1:
The damping force dynamically adapts to operating conditions rather than remaining constant. During normal operation, low damping minimizes energy loss and maintains fuel efficiency. During starting and boost modes, high damping ensures belt tension stability and prevents oscillations, resolving the contradiction between reliability and energy efficiency.
Solution Approach 2:
The damping parameter is varied based on operational requirements. The system switches between low-damping and high-damping states, optimizing the balance between belt tension stability and fuel efficiency for different operating modes.
3Use of energy by moving object
If low damping is used to minimize drag torque, then fuel efficiency improves, but oscillations and vibrations increase during starting and boost modes
Solution Approach 1:
The damping characteristic transitions from low to high based on operating mode. During normal operation, low damping maintains fuel efficiency. During starting and boost modes, the damping force increases to suppress oscillations and vibrations, resolving the contradiction between energy efficiency and vibration control.
Solution Approach 2:
The damping parameter is adjusted according to operational demands. The system employs variable damping that switches between low and high states, optimizing both fuel efficiency during normal operation and vibration control during high-load modes.
4Device complexity
If a single damping value is used for all operating conditions, then device complexity is reduced, but performance optimization across different modes becomes impossible
Solution Approach 1:
The damping mechanism automatically adapts to different operating modes through its inherent friction characteristic without requiring external control systems. The variable damping force is generated self-service by the damping element's interaction with the bearing surface, maintaining simplicity while achieving adaptability across different operating conditions.
Solution Approach 2:
The damping parameter changes based on operating conditions through the damping element's friction characteristic. This natural parameter variation enables the system to adapt to different modes without adding complex control mechanisms, resolving the contradiction between simplicity and adaptability.
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 solution effectively reduces oscillations and vibrations by providing adaptive damping, ensuring optimal belt tension and minimizing drag torques, thus improving fuel efficiency and operational stability across different operating conditions.
Implementation Method 1
A belt tensioning device with a damping mechanism that generates varying damping torque based on the rotational position and direction of the tensioning arm relative to the base body, utilizing different coefficients of friction
Implementation Method 2
a spring arrangement which is arranged between the first tensioning arm and the second tensioning arm, via which the first tensioning arm and the second tensioning arm are resiliently supported against one another in the circumferential direction
Data Source
AI summary
A belt tensioning device includes a first tensioning arm mounted on a base body pivotably about a first pivot axis and includes a rotatable first tensioning roller. A second tensioning arm is pivotably mounted relative to the base body about a second pivot axis and includes a rotatable second tensioning roller. Via a spring arrangement between the first tensioning arm and the second tensioning arm, the first and second tensioning arms are resiliently supported against one another in the circumferential direction. A damping mechanism is operatively arranged between the base body and the first tensioning arm for damping relative rotational movement between the first tensioning arm and the base body.The damping mechanism generates a varying damping torque dependent on the rotational position and/or rotational direction of the first tensioning arm relative to the base body upon pivoting of the first tensioning arm relative to the base body.