Transmission Synchronizer Damping Material for Noise Reduction
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Solution Overview
Problem
Transmission synchronizer assemblies experience noise due to functional clearances and backlashes between components, leading to rattling sounds as torque varies during engagement.
Innovation Solution
A synchronizer ring with radially extending tabs and an annular hub featuring recesses, where a damping material with greater compliance than the tab and hub materials is placed in the clearance, ensuring contact with the hub during movement, reducing noise through damping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If functional clearances are provided between components, then seamless shifts and prevention of driveline torque spikes are achieved, but rattling noise occurs as torque varies
Solution Approach 1:
A damping material is introduced as an intermediary element between the synchronizer ring tabs and the hub recesses. This damping material fills the functional clearances and absorbs vibrations, preventing the tabs from directly contacting the recesses during torque variations, thereby eliminating rattling noise while maintaining the necessary clearance for seamless engagement
Solution Approach 2:
The damping material changes the physical parameters of the clearance space by introducing a viscoelastic substance that can deform and absorb energy. This material has different mechanical properties (damping coefficient, compliance) compared to the rigid metal components, allowing it to absorb vibrations and reduce noise while maintaining the functional clearance
2Object-generated harmful factors
If damping material is added to reduce noise, then rattling sounds are reduced, but device complexity increases
Solution Approach 1:
The damping material is merged with the hub structure by positioning it within the existing recesses of the hub. This integration approach combines the noise-damping function with the existing structural features, avoiding the need for separate damping components or additional assembly steps, thereby minimizing the increase in device complexity
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 damping material effectively absorbs noise and vibrations, enhancing the smooth operation and reducing rattling sounds during gear engagement, thereby improving occupant comfort.
Implementation Method 1
A damping material is provided in the clearance such that the damping material contacts the annular hub when the synchronizer is moved about the axis of rotation relative to the annular hub
Implementation Method 2
The damping material is selected to have a compliance that is greater than the compliance of at least one of the tab and the hub
Data Source
AI summary
A transmission synchronizer assembly is provided that alleviates noise associated with functional clearances and backlashes. A synchronizer ring is provided that has a periphery with at least one tab extending at least partially radially at the periphery. An annular hub has at least one recess configured to receive the at least one tab to axially align the synchronizer ring with the hub. The recess and the tab define a clearance when the tab is received in the recess. A damping material is provided in the clearance such that the damping material contacts the annular hub when the synchronizer is moved about the axis of rotation relative to the annular hub. Such movement may occur during engagement of an annular sleeve with a gear whose speed is synchronized with the sleeve by the synchronizer ring.