Transmission Drum Low-Rigidity Structure for Vibration Damping

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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 configuration of the drum member attached to the transmission path constituent member, which also leads to vibration and noise issues within the vehicle interior.

Innovation Solution

Incorporating low-rigidity parts such as through holes or grooves in the drum member allows for vibration damping and weight reduction, with the ability to set the natural frequency of the drum member, thereby reducing vibration and noise transmitted to the vehicle interior.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a damper is attached to the drum member to damp vibration, then vibration reduction is achieved, but weight and cost increase

Engineering Contradiction:
ImprovevibrationVSAvoiddrum member weight
Core Design Contradiction:
Object-affected harmful factorsVSWeight of moving object

Solution Approach 1:

The patent applies local quality by creating low-rigidity parts (through holes or grooves) at specific locations on the drum member rather than uniformly modifying the entire structure. This localized modification damps vibration at critical areas while preserving the overall structural integrity and minimizing weight addition compared to attaching a separate damper component.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent merges the vibration damping function directly into the drum member structure by forming low-rigidity parts as integral features of the drum member itself. This eliminates the need for a separate damper component, thereby avoiding the weight and cost penalties associated with attaching an additional vibration damping device.

Inventive Principle:
Principle #5Merging (Combining)

2Object-affected harmful factors

If a damper is attached to the drum member to damp vibration, then vibration reduction is achieved, but manufacturing cost increases

Engineering Contradiction:
ImprovevibrationVSAvoidmanufacturing cost
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent combines the vibration damping function with the drum member structure itself, eliminating the need for a separate damper component. This integration reduces part count, simplifies assembly, and lowers manufacturing costs while achieving the desired vibration damping effect through the low-rigidity parts.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

By creating localized low-rigidity features (through holes or grooves) rather than modifying the entire drum member or adding a separate damper, the patent achieves vibration damping with minimal material removal or added complexity, thereby controlling manufacturing costs effectively.

Inventive Principle:
Principle #3Local quality

3Volume of moving object

If the drum member is positioned adjacent to the transmission case, then space utilization is improved, but sound radiation increases

Engineering Contradiction:
Improvespace utilizationVSAvoidsound radiation
Core Design Contradiction:
Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by creating low-rigidity parts at specific locations on the drum member to damp vibration and reduce sound radiation. This localized modification allows the drum member to remain positioned adjacent to the transmission case for efficient space utilization while mitigating sound radiation through targeted vibration damping at critical areas.

Inventive Principle:
Principle #3Local quality

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

This configuration achieves weight reduction and cost inhibition while effectively damping vibrations and noise in the vehicle interior by adjusting the number, size, and placement of low-rigidity features in the drum member.

Implementation Method 1

Incorporating low-rigidity parts such as through holes or grooves in the drum member allows for vibration damping and weight reduction

Methodology Applied
Scientific EffectVibration damping: Damping

Data Source

PatentEP3708859B1Automatic transmission power transmission device
Publication Date: 2022.12.21 MAZDA MOTOR CORP
  • EP3708859B1 patent drawingFigure 1
  • EP3708859B1 patent drawingFigure 2
  • EP3708859B1 patent drawingFigure 3

AI summary

A power transmission device in an automatic transmission (10) includes a friction tightening element (a second brake (24)) having a drum member (31), and a transmission path constituent member (a third ring gear (R3)) coupled to the drum member (31) via a coupling part (41) extending circumferentially along the drum member (31), the drum member (31) having low-rigidity parts (long holes (31c)) provided at a plurality of circumferential positions on the drum member (31) in at least one of portions radially outside and inside the coupling part (41).