Planetary Gearbox Assembly with Axial Fixing and Helical Gears

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Solution Overview

Problem

Existing gearbox assemblies face challenges in easy assembly, noise reduction, and reliability in high vibration environments, particularly due to interference during assembly and potential dislodging of radial pins under vibration.

Innovation Solution

A gearbox assembly design featuring inner gear rings and gear groups with planetary and solar gears, where fixing members are inserted from the input end to attach the connector component before assembly, reducing interference and enhancing reliability, and using helical gears with specific tooth angles to minimize noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the connection to the output shaft is installed first during assembly, then the bearings are protected from damage, but the installation of fasteners is interfered with

Engineering Contradiction:

Improvebearing protectionVSAvoidfastener installation

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The fastening system is segmented into two independent parts: fixing members (screws) that attach inner gear rings to the mounting plate, and a separate connector component that couples the output shaft to the application. This segmentation allows the connector to be pre-assembled on the output shaft without blocking the path of fixing members during gearbox assembly.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The connector component is preliminarily assembled to the output shaft before the gearbox assembly process. This preliminary action enables the output shaft connection to be established in advance, protecting the bearings during subsequent assembly operations, while the fixing members can still be freely inserted from the output end through the cover and inner gear rings without interference.

Inventive Principle:

Principle #10Preliminary action

2Ease of operation

If radial pins are used to attach gear rings and the gearbox to the motor, then assembly is simplified, but the pins may come out in high vibration environments

Engineering Contradiction:

Improveassembly simplicityVSAvoidconnection stability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

Instead of using radial pins that protrude outward from the gear rings (which can dislodge under vibration), the design inverts the approach by using fixing members that insert axially through the inner gear rings from the output end. This axial insertion method provides superior vibration resistance while maintaining assembly simplicity.

Inventive Principle:

Principle #13The other way round (Inversion)

3Ease of manufacture

If standard gears are used, then manufacturing is easier, but noise is increased

Engineering Contradiction:

Improvegear manufacturingVSAvoidnoise

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The gear design changes the tooth profile parameter from standard involute to helical teeth with a specific helix angle. This parameter change transforms the engagement from line contact to gradual contact along the tooth width, significantly reducing noise and vibration while remaining manufacturable using standard helical gear cutting processes.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9303729B2Planetary gearbox and process for assembling the same

Publication Date: 2016.04.05 JOHNSON ELECTRIC INTERNATIONAL AG

AI summary

A gearbox assembly (10) configured for easy to assembling comprises a plurality of gears (30) configured to spin within a plurality of inner gear rings (20, 22). Fixing mechanisms (40) are axially inserted from the input side (12) of the gearbox, thereby allowing for a connector (90) to be attached to the output shaft (62) of the gearbox prior to gearbox assembling.