Compact Power Transmission Device Using Nested Planetary Gears

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Solution Overview

Problem

Conventional power transmission devices have a high installation height, require complex peripheral accessories, and necessitate frequent maintenance and cleaning, making them unsuitable for compact equipment and prone to process delays.

Innovation Solution

A power transmission device with a simple structure featuring a planetary gear train, ring gear, and rollers that reduce installation height, eliminate the need for complex accessories, and minimize maintenance and cleaning requirements, utilizing a lubrication system to prevent contamination and facilitate smooth operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If a conventional power transmission device with a protruding shaft and coupled pinion is used, then the pinion can be engaged with the rack to enable linear motion, but the installation height increases making it difficult to apply to compact equipment

Engineering Contradiction:
Improveinstallation heightVSAvoidengagement with rack
Core Design Contradiction:
Length of moving objectVSEase of operation

Solution Approach 1:

The pinion is integrated directly into the rotary actuator body, merging the motor housing and pinion into a single compact unit. This eliminates the need for a separate protruding shaft and external pinion coupling, thereby reducing installation height while maintaining the engagement function with the rack.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The pinion is nested within the rotary actuator housing rather than extending outward. This nested configuration allows the pinion to be housed inside the actuator body, significantly reducing the overall installation height while preserving the mechanical engagement capability with the rack.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Device complexity

If a conventional power transmission device with external pinion and shaft is used, then the structure can transmit power, but complicated peripheral accessories such as gear box or shrink fitting coupling are needed

Engineering Contradiction:
Improveperipheral accessoriesVSAvoidpower transmission capability
Core Design Contradiction:
Device complexityVSPower

Solution Approach 1:

The gear box function is merged into the rotary actuator by directly integrating the pinion with the motor shaft inside the actuator housing. This eliminates the need for external gear boxes or shrink fitting couplings, reducing device complexity while maintaining full power transmission capability through the integrated drive mechanism.

Inventive Principle:
Principle #5Merging (Combining)

3Object-affected harmful factors

If a conventional power transmission device with exposed pinion is used, then the pinion can be engaged with the rack, but lubrication oil is coated on the outer surface causing contamination of the vicinity

Engineering Contradiction:
ImprovecontaminationVSAvoidengagement with rack
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The pinion is nested within the rotary actuator housing, which encloses the lubrication oil and prevents it from coating the outer surface. This nested configuration maintains the engagement function with the rack through the housing interface while preventing lubrication oil leakage and contamination of the surrounding environment.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The rotary actuator housing acts as an enclosing shell that contains the lubrication oil within the pinion assembly. This shell structure prevents the lubrication oil from escaping to the outer surface, thereby preventing contamination of the vicinity while allowing the pinion to engage with the rack through the housing.

Inventive Principle:
Principle #30Flexible shells and thin films

4Productivity

If a conventional power transmission device with exposed shaft and pinion is used, then the structure can transmit motion, but maintenance work and cleaning work are frequently needed causing process delay

Engineering Contradiction:
Improveprocess continuityVSAvoidmaintenance requirements
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The pinion and shaft are nested within the rotary actuator housing, creating a sealed maintenance-free configuration. This nested structure protects the internal components from contamination and reduces the frequency of maintenance and cleaning operations, thereby improving process continuity and reducing downtime.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The sealed rotary actuator housing with integrated pinion creates a self-contained system that requires minimal external maintenance. The design allows the unit to operate for extended periods without intervention, reducing the frequency of maintenance work and cleaning operations needed to maintain process continuity.

Inventive Principle:
Principle #25Self-service

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 solution reduces installation height, minimizes the use of complex accessories, and significantly decreases maintenance and cleaning frequencies, thereby preventing process delays and enabling easier application to compact equipment.

Implementation Method 1

a planetary gear train circumscribing the input gear around the input gear and rotating in association with a rotation of the input gear

Methodology Applied
Scientific EffectGear: Gear

Implementation Method 2

a main frame to which a plurality of rollers that interact with a rack and relatively rotate are coupled

Methodology Applied
Scientific EffectRolling friction: Roller

Data Source

PatentEP2634456B1Power transmission device
Publication Date: 2018.01.17 SEJIN IGB CO LTD
  • EP2634456B1 patent drawingFigure 1~2
  • EP2634456B1 patent drawingFigure 3
  • EP2634456B1 patent drawingFigure 4

AI summary

Disclosed is a power transmission device. A power transmission device according to one embodiment of the present invention includes: an input gear connected to a motor so that the input gear may rotate by the motor in a forward and backward direction; a planetary gear train circumscribing the input gear with respect to the input gear and rotating in association with the rotation of the input gear; a ring gear inscribing the planetary gear train and rotating relative to the planetary gear train; a main frame having a plurality of rollers coupled along the circumferential direction and interacting with a rack, and coupled with the ring gear on the outside of the ring gear; an irrotational rear side fixture disposed on an area where the input gear is positioned; and an irrotational front side fixture disposed at the opposite side of the irrotational rear side fixture via the ring gear and the main frame therebetween and coupled with the irrotational rear side fixture.