Power Take-Off Gear Axis Offset for Neutral Rattle Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Power take-offs in vehicles often transmit torsional vibrations from the source of rotational energy to rotatably driven accessories, resulting in undesirable neutral rattle noise due to the inherent tooth clearance in meshing gears, which is not effectively mitigated by current designs.
Innovation Solution
The power take-off design features a housing with an input mechanism and output mechanism where the rotational axes of the input gear and driving or driven gears are misaligned, minimizing the transmission of torque transients and vibrations, thereby reducing or eliminating neutral rattle noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rotational axes of meshing gears are aligned, then efficient power transmission is achieved, but torsional vibrations and neutral rattle noise are transmitted to the driven accessory
Solution Approach 1:
The patent introduces an intermediary element - the offset coupling mechanism with misaligned rotational axes - that decouples the vibration transmission path from the power transmission path. This allows power to be transmitted efficiently while vibrations are isolated and damped by the offset configuration
Solution Approach 2:
The patent applies asymmetry by deliberately misaligning the rotational axes of the input gear and output gear. This asymmetric configuration creates an offset coupling that naturally dampens torsional vibrations and eliminates neutral rattle noise while maintaining power transmission functionality
2Object-generated harmful factors
If tooth clearance in meshing gears is reduced, then vibration transmission is minimized, but manufacturing precision requirements increase and gear wear increases
Solution Approach 1:
The offset coupling acts as an intermediary that eliminates the need for tight tooth clearance control. By misaligning the rotational axes, the system achieves vibration reduction without requiring precision manufacturing of gear tooth clearances
Solution Approach 2:
The patent changes the geometric parameter of gear axis alignment from zero offset to a deliberate non-zero offset. This parameter change transforms the vibration transmission characteristics without affecting gear tooth clearance specifications
Data Source
AI summary
A power take-off includes a housing including a mounting surface that is adapted to be secured to a source of rotational energy. The mounting surface has an opening therethrough. An input mechanism includes an input gear that has a portion that extends outwardly from the housing through the opening provided through the mounting surface and is adapted to extend within and be rotatably driven about an input gear rotational axis by a driving gear contained within the source of rotational energy. An output mechanism is disposed within the housing and includes a driven gear that is rotatably driven about an output gear rotational axis by the input gear of the input mechanism. The rotational axis of the input gear and the rotational axis of the driven gear are movable relative to one another so as to minimize the transmission of torque transients and other vibrations therethrough during operation.