Planetary Gear Housing Isolation With Raised Contact Ridges

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Solution Overview

Problem

Planetary gear devices experience noise and vibration issues due to the transmission of vibrations from the inner gear to the housing, despite previous attempts to mitigate these through separate structural units, as the contact area between the inner gear and housing remains significant, leading to continued noise production.

Innovation Solution

The implementation of separate structural units for the inner gear and housing, featuring raised portions on both components that create a gap and limit movement through linear contact, reducing the contact area and thereby minimizing vibration transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the inner gear and housing are formed with fitting shapes that enable contact, then the inner gear is constrained in position, but the contact area becomes significant causing vibration transmission and noise

Engineering Contradiction:
ImprovePosition stability of inner gearVSAvoidVibration transmission and noise
Core Design Contradiction:
Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The patent applies segmentation by dividing the contact interface into multiple discrete contact points through raised portions on both the inner gear and housing. Instead of continuous surface contact, the contact is segmented into specific localized areas where raised portions meet, reducing the overall contact area while maintaining positional constraint. This segmentation principle directly addresses the contradiction by allowing position stability through discrete contacts while minimizing vibration transmission through reduced contact surface.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements local quality by creating non-uniform contact distribution through strategically positioned raised portions. The contact properties are made local rather than uniform across the entire interface - specific localized areas have contact while other areas maintain gaps. This allows the system to achieve position stability at critical locations while minimizing overall contact area to reduce vibration and noise transmission.

Inventive Principle:
Principle #3Local quality

2Object-generated harmful factors

If the inner gear and housing are separated with a gap, then vibration transmission is reduced, but the inner gear movement becomes uncontrolled

Engineering Contradiction:
ImproveVibration transmissionVSAvoidPosition stability of inner gear
Core Design Contradiction:
Object-generated harmful factorsVSStability of the object's composition

Solution Approach 1:

The patent resolves this contradiction by segmenting the gap structure - instead of a complete continuous gap, there are localized contact points formed by raised portions that provide positional constraint. The majority of the interface maintains separation with gaps to reduce vibration transmission, while specific segmented contact areas prevent uncontrolled movement of the inner gear.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The raised portions act as intermediary elements that mediate between the need for separation and the need for constraint. These protruding features serve as intermediate contact points that provide positional stability without requiring full surface contact, thus maintaining vibration reduction benefits while preventing uncontrolled gear movement.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If continuous surface contact is provided between inner gear and housing, then position constraint is achieved, but noise production increases due to significant contact area

Engineering Contradiction:
ImprovePosition constraint of inner gearVSAvoidNoise production
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent applies segmentation by replacing continuous surface contact with discrete localized contact points formed by raised portions. This segmentation reduces the total contact area significantly while still providing adequate position constraint for the inner gear. The broken-up contact pattern minimizes the transmission path for vibrations and noise while maintaining functional constraint.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts the essential constraint function from continuous contact and concentrates it into discrete raised portions. By taking out only the necessary contact elements needed for position constraint and removing the rest of the continuous contact surface, the design achieves position control with minimal contact area, thereby reducing noise production.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentUS11927260B2Gear housing for a planetary gear device that structurally isolates an inner gear
Publication Date: 2024.03.12 ENPLAS CORP
  • US11927260B2 patent drawing
  • US11927260B2 patent drawing
  • US11927260B2 patent drawing

AI summary

Separate structural units for an inner gear and a housing of a planetary gear device include an inner gear with a first raised portion formed on the outer peripheral surface of the inner gear, where the first raised portion extends towards in a direction that is inclined with respect to the axial direction of the inner gear. A housing includes a second raised portion formed on an inner peripheral surface, where the second raised portion extends in a direction that is inclined in respect to the axial direction. The housing contains the inner gear such that there is a gap formed between the inner peripheral surface of the housing and the outer peripheral surface of the inner gear. Movement of the inner gear within the interior of the housing is limited through linear contact of the first raised portion and the second raised portion.