Harmonic Reducer Venting Structure to Prevent Pressure Buildup

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Solution Overview

Problem

Conventional harmonic reducers experience internal pressure buildup and lubricant leakage due to temperature increases, leading to contamination and reduced lubricating performance, especially in industrial robots, where manual gas release is hazardous and impractical during operation.

Innovation Solution

A harmonic reducer design featuring a shaft with a through hole allowing fluid communication between the internal cavity and external environment, equipped with a sealing mechanism that opens to release pressure when internal pressure exceeds a threshold, preventing lubricant leakage and maintaining low internal pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a gas release hole closed by a plug is provided on the harmonic reducer, then internal pressure buildup can be prevented, but manual operation is hazardous and impractical during operation

Engineering Contradiction:

Improveprevention of internal pressure buildupVSAvoidmanual gas release operation

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The sealing mechanism automatically releases gas when internal pressure exceeds the threshold, eliminating the need for manual operation. The mechanism serves itself by using the pressure differential to open the sealing element and release gas, then automatically closes when pressure normalizes.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The manual mechanical plug operation is replaced with an automatic sealing mechanism that uses elastic deformation of the sealing element and pressure differential to achieve gas release without human intervention.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Power

If the harmonic reducer operates at high temperature, then power transmission function is maintained, but lubricant vaporization causes pressure buildup and leakage

Engineering Contradiction:

Improvepower transmissionVSAvoidinternal temperature

Core Design Contradiction:

PowerVSTemperature

Solution Approach 1:

The harmful gas and vapor that cause pressure buildup are extracted from the internal cavity through the gas release hole, allowing the harmonic reducer to continue operating at high temperature without pressure accumulation or lubricant leakage.

Inventive Principle:

Principle #2Taking out (Extraction)

3Reliability

If the internal pressure is released, then gas buildup is prevented, but debris may enter through the opening

Engineering Contradiction:

Improvepressure controlVSAvoiddebris contamination

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The sealing element provides different properties at different times: it remains closed to prevent debris entry under normal conditions, and opens to allow gas release when pressure exceeds the threshold. The local quality of the sealing interface changes dynamically based on pressure conditions.

Inventive Principle:

Principle #3Local quality

4Object-affected harmful factors

If a sealing mechanism is added to prevent debris entry, then contamination is reduced, but device complexity increases

Engineering Contradiction:

Improvedebris contaminationVSAvoidsealing mechanism structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The sealing mechanism uses a flexible sealing element that can elastically deform to open and close the gas release hole. This thin-film approach provides effective sealing and automatic pressure release functionality with minimal structural complexity.

Inventive Principle:

Principle #30Flexible shells and thin films

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

Effectively prevents lubricant leakage and maintains low internal pressure in the harmonic reducer, ensuring reliable operation and safety by automatically releasing gas and preventing debris entry, thus enhancing the durability and performance of industrial robots.

Implementation Method 1

an elastic sealing element configured to block the communication between the cavity and the external environment through the first through hole when an internal pressure of the cavity is below a pressure threshold and configured to release gas from the cavity to the external environment through the first through hole when the internal pressure of the cavity is above the pressure threshold

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentUS12104687B2Harmonic reducer with structure to prevent pressure buildup and industrial robot

Publication Date: 2024.10.01 ABB (SCHWEIZ) AG

AI summary

A harmonic reducer includes a shaft having a first through hole extending from a first end to a second end of the shaft; a wave generator arranged on the shaft and being rotatable along with the shaft; a flexible spline arranged around the wave generator; a circular spline arranged around the flexible spline; a first flange coupled to the shaft via a first bearing and coupled to the flexible spline; and a second flange coupled to the shaft via a second bearing and coupled to the circular spline. One of the flanges is arranged near to the first end of the shaft. A cavity is provided between the one of the flanges and the first end of the shaft, such that it is in fluid communication with an external environment via the first through hole.