Intermediary Gear Biasing for Gear Rattle Attenuation
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Solution Overview
Problem
Gear trains transmit vibrational disturbances through meshing teeth, leading to objectionable acoustical issues and structural excitations due to manufacturing and mounting tolerances, which existing technologies fail to adequately address.
Innovation Solution
A control system with a biasing force mechanism, applied through a control module, adjusts the engagement of intermediary gears to improve gear mesh engagement, reducing or eliminating gear rattle by deflecting intermediary gears during unloaded conditions and allowing them to return to their design position under load, using various force application methods such as springs, fluid pressure, or magnetic fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If gear teeth are designed with looseness to accommodate tolerances, then manufacturing and assembly are easier, but vibrational disturbances and gear rattle increase
Solution Approach 1:
A control module is introduced as an intermediary component between the gear and housing. This control module includes a biasing mechanism that applies a controlled biasing force to deflect the gear, thereby pre-loading the gear mesh to eliminate looseness and reduce vibrations while maintaining ease of manufacture.
Solution Approach 2:
The system dynamically changes the mesh stiffness parameter by applying a biasing force that deflects the gear. This alters the contact conditions between gear teeth, transforming the system from a loose, vibration-prone state to a pre-loaded, stable mesh state that reduces vibrational disturbances.
2Object-affected harmful factors
If gear mesh engagement is increased to reduce vibrations, then vibrational attenuation improves, but the complexity of the control system increases
Solution Approach 1:
The patent offers alternative embodiments where complex mechanical biasing mechanisms are replaced with simpler field-based systems. Electromagnetic actuators or magnetic biasing mechanisms can provide the necessary biasing force without complex mechanical linkages, reducing overall system complexity while maintaining vibration attenuation effectiveness.
Solution Approach 2:
The control module is designed to automatically adjust and maintain optimal gear mesh engagement through its biasing mechanism. The system self-regulates the deflection to maintain proper pre-load, reducing the need for external control systems or manual adjustments, thereby minimizing added complexity.
3Object-affected harmful factors
If biasing force is applied to deflect intermediary gears during unloaded conditions, then gear rattle is reduced, but the force required may interfere with power transfer under load
Solution Approach 1:
The control module employs a dynamic biasing mechanism that can adjust the biasing force in real-time. During unloaded conditions, the biasing force is applied to eliminate gear rattle. During loaded conditions, the system dynamically modulates or reduces the biasing force to prevent interference with power transfer, maintaining optimal performance across varying operating conditions.
Solution Approach 2:
The biasing force is applied periodically or in a controlled manner rather than continuously. The system activates the biasing mechanism during unloaded or idle periods to reduce gear rattle, and deactivates or reduces it during power transfer phases, allowing the gear mesh to engage naturally under load without excessive pre-loading that would impede power transmission.
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 control system effectively attenuates gear vibrations, reducing noise and structural excitations by enhancing gear mesh engagement, thereby improving the operational stability and reducing gear rattle across varying load conditions.
Implementation Method 1
the control module includes a spring that is configured to apply the biasing force
Implementation Method 2
the control module includes a magnet that is configured to apply the biasing force
Implementation Method 3
the control module includes a pressurized fluid that is configured to apply the biasing force to the control element
Data Source
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AI summary
A power take off unit includes an input gear, an output gear and an intermediary gear that cooperate to transfer power from a rotational power source to an operating target. The power take off unit having a control module that biases the intermediary gear relative to the input gear and the output gear to reduce gear rattle vibrations associated with intermeshed tooth looseness.