Coaxial Motor Reducer Sealing to Prevent Gear Dislocation

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Solution Overview

Problem

Conventional motor reducers used in weighing machines often experience gear train dislocation and lubricant leakage due to their axial protrusion and vibration during use, which complicates maintenance and increases the risk of fretting.

Innovation Solution

A motor reducer design featuring a reduction gear train with a coaxial planetary gear and a separate input cover that seals the motor-side end face, along with a labyrinth groove structure to prevent lubricant leakage, reduces the axial length and weight, and enhances rigidity and sealing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the electric motor and motor reducer are coupled in series with conventional sealing, then the structure is simple, but the reduction gear train may fall off from the motor-side end face when separated, and the axial length becomes large

Engineering Contradiction:

Improvesealing structureVSAvoidgear train position stability

Core Design Contradiction:

Device complexityVSStability of the object's composition

Solution Approach 1:

The motor reducer is divided into separate components: the reducer casing containing the gear train, and a separate input cover that seals the motor-side end face. This segmentation allows the gear train to remain securely contained within the reducer casing while enabling separate assembly and maintenance of the motor and reducer components.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The input cover is pre-installed on the reducer casing before motor assembly, creating a sealed enclosure that prevents gear train dislocation. This preliminary sealing action ensures the gear train is secured in place before the motor is coupled to the reducer, eliminating the risk of gear train fall-off during separation.

Inventive Principle:

Principle #10Preliminary action

2Device complexity

If the axial protrusion dimension is large, then the sealing is simpler, but stress acts on the connection portion due to vibration, requiring increased coupling face rigidity

Engineering Contradiction:

Improvesealing structureVSAvoidconnection portion strength

Core Design Contradiction:

Device complexityVSStrength

Solution Approach 1:

By separating the sealing function into an independent input cover component rather than relying on axial protrusion, the connection portion between motor and reducer is freed from bearing excessive stress. The segmented design allows each component to be optimized independently for its specific function.

Inventive Principle:

Principle #1Segmentation

3Device complexity

If conventional sealing without labyrinth groove is used, then the structure is simpler, but lubricant leaks to the outside

Engineering Contradiction:

Improvesealing structureVSAvoidlubricant leakage

Core Design Contradiction:

Device complexityVSLoss of substance

Solution Approach 1:

The input cover acts as a flexible sealing barrier between the internal gear train environment and the external motor environment. This sealed cover prevents lubricant from escaping while allowing for thermal expansion and contraction of the internal components.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The input cover serves as an intermediary sealing element between the motor shaft and the external environment. It creates a barrier that prevents direct contact between the lubricant and the outside, thereby preventing leakage while maintaining the functional connection between motor and reducer.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Stability of the object's composition

If multiple bearings are used in the reduction gear train, then the gear train is more stable, but the axial length and weight increase, and manufacturing cost increases

Engineering Contradiction:

Improvegear train stabilityVSAvoidaxial length

Core Design Contradiction:

Stability of the object's compositionVSLength of moving object

Solution Approach 1:

The planetary gear and motor shaft are merged into a coaxial configuration, eliminating the need for separate bearing supports for the planetary gear carrier. This integration reduces the number of bearings required while maintaining gear train stability through the rigid coaxial connection.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The motor shaft serves multiple functions: it acts as both the driving element and the support structure for the planetary gear. This multi-functionality eliminates the need for additional dedicated support components, reducing axial length and weight while maintaining structural stability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 design prevents gear train dislocation and lubricant leakage, facilitating maintenance and reducing the risk of fretting, while also reducing manufacturing costs and improving the overall structural integrity of the motor reducer.

Implementation Method 1

a labyrinth groove may be provided between an inner peripheral face of the penetration hole and an outer peripheral face of the cylindrical body

Methodology Applied

Scientific EffectLabyrinth groove sealing:

Data Source

PatentUS11746880B2Motor reducer

Publication Date: 2023.09.05 KANZAKI KOKYUKOKI MFG

AI summary

A motor reducer of the at least an embodiment of the present invention includes a reduction gear train that decelerates rotation input from a motor, and a reducer casing that accommodates the reduction gear train. An input cover that seals a motor-side end face of the reducer casing is provided, and the input cover is provided separately from the motor casing.