Automatic Transmission Drum Holes for Vibration and Noise Reduction
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Solution Overview
Problem
The existing automatic transmission power transmission devices face challenges in weight reduction and cost inhibition due to the weight and cost increase of the drum member coupled to the transmission path constituent member, while also generating vibration and noise in the vehicle interior.
Innovation Solution
Incorporating low-rigidity parts such as through holes or grooves on the drum member at various circumferential positions, which allows for vibration damping and natural frequency adjustment without the need for a damper, thereby reducing vibration and noise while maintaining weight reduction and cost efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a damper with mass part and elastic parts is attached to the drum member, then vibration of the drum member is damped, but weight and cost of the drum member increase
Solution Approach 1:
The invention applies local quality by creating low-rigidity regions at specific locations on the drum member through circumferential grooves or holes. These localized modifications alter the vibration characteristics of the drum member without requiring a complete structural redesign or attachment of additional damping components, thereby avoiding weight increase while achieving vibration damping at critical areas.
Solution Approach 2:
The invention changes the physical parameters of the drum member by introducing circumferential grooves or holes that modify its rigidity distribution and natural frequency. This parameter change allows the drum member itself to exhibit damping characteristics, eliminating the need for external dampers and reducing overall weight while maintaining vibration control.
2Object-affected harmful factors
If a damper with mass part and elastic parts is attached to the drum member, then vibration of the drum member is damped, but cost of the drum member increases
Solution Approach 1:
The invention merges the damping function into the drum member structure itself by incorporating circumferential grooves or holes directly during drum member manufacturing. This integration eliminates the need for separate damper components and their associated assembly processes, thereby reducing part count, simplifying manufacturing, and lowering costs while achieving vibration damping.
Solution Approach 2:
The drum member is designed to serve multiple functions: it maintains its primary function of transmitting torque while simultaneously providing vibration damping through its modified structure. The circumferential grooves or holes create low-rigidity regions that damp vibration, allowing the drum member to be both a structural component and a damping element, reducing the need for additional specialized parts.
3Reliability
If the drum member is positioned adjacent to the transmission case, then brake tightening can fix the transmission path constituent member, but vibration generates sound radiation that vibrates the transmission case through air
Solution Approach 1:
The invention applies local quality by creating low-rigidity regions at specific locations on the drum member through circumferential grooves or holes. These localized modifications alter the vibration characteristics of the drum member without requiring a complete structural redesign or attachment of additional damping components, thereby avoiding weight increase while achieving vibration damping at critical areas.
Solution Approach 2:
The invention converts the potentially harmful vibration and sound radiation into a beneficial effect by designing the drum member's low-rigidity regions to absorb and dissipate vibration energy. The circumferential grooves or holes create damping effects that reduce the amplitude of vibrations, thereby converting what would be harmful sound radiation into controlled, minimized vibrations that protect the transmission case and reduce noise.
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 configuration effectively reduces vibration and noise in the vehicle interior, achieves weight reduction, and inhibits cost increase by allowing the drum member to have a desired natural frequency, enhancing the overall performance of the automatic transmission power transmission device.
Implementation Method 1
the low-rigidity parts damp vibration generated at the transmission path constituent member so as to reduce vibration of the drum member
Implementation Method 2
The vibration of the drum member has a natural frequency that can be set to a desired value not by applying a damper but by adjusting the number of through holes or grooves provided circumferentially along the drum member
Data Source
AI summary
A power transmission device in an automatic transmission includes a friction tightening element (a second brake) having a drum member, and a transmission path constituent member (a third ring gear) coupled to the drum member via a coupling part extending circumferentially along the drum member, the drum member having low-rigidity parts (long holes) provided at a plurality of circumferential positions on the drum member in at least one of portions radially outside and inside the coupling part.