Harmonic Reducer Pressure-Relief Sealing for Lubricant Leakage
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Solution Overview
Problem
Harmonic reducers experience internal pressure buildup due to temperature increases and lubricant vaporization, leading to lubricant leakage through oil seals, which degrades performance and contaminates surrounding equipment.
Innovation Solution
A harmonic reducer design featuring a shaft with a through hole that allows the cavity inside the reducer to be in fluid communication with the external environment, equipped with a sealing mechanism that selectively opens to release pressure when it exceeds a threshold, preventing lubricant leakage.
Engineering Contradictions & Design Principles
Engineering 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 the operator cannot safely open the plug during operation and may be injured
Solution Approach 1:
The system automatically releases gas when internal pressure exceeds the spring pre-force, without requiring operator intervention. The valve opens when P_internal > F_spring/S_area, allowing the system to self-regulate pressure and eliminate the hazard of manual plug opening during operation
Solution Approach 2:
The manual mechanical plug system is replaced with an automatic spring-loaded valve mechanism that uses elastic force to control gas release, transforming a dangerous manual operation into an automated safety mechanism
2Reliability
If the cavity is opened to the external environment, then internal pressure is reduced, but debris from the external environment may enter the harmonic reducer
Solution Approach 1:
The valve provides localized controlled opening only when needed for pressure relief, rather than keeping the entire cavity open. The valve area is small and selective, allowing gas escape while blocking debris entry through its sealed design that only opens under pressure differential
Solution Approach 2:
The valve transitions from a closed static state to an open dynamic state only when internal pressure exceeds the spring pre-force, providing dynamic pressure regulation while maintaining protection against debris during normal operation
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 effectively maintains low internal pressure within the harmonic reducer, preventing lubricant leakage and ensuring reliable operation, while also preventing debris from entering the reducer.
Implementation Method 1
a second sealing element arranged between the first sealing element and the base element, and comprising an elastic sealing lip configured to contact the sealing surface of the first sealing element to block the communication between the cavity and the second through hole when the internal pressure of the cavity is below a pressure threshold and configured to be pushed away from the sealing surface of the first sealing element to communicate the cavity with the second through hole when the internal pressure of the cavity is above the pressure threshold
Data Source
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AI summary
A harmonic reducer (100) and an industrial robot. The harmonic reducer (100) comprises a shaft (4) comprising a first through hole (403) extending from a first end (401) to a second end (402) of the shaft (4) in an axial direction (X) of the shaft (4); a wave generator (13) arranged on the shaft (4) and being rotatable along with the shaft (4); a flexible spline (11) arranged around the wave generator (13); a circular spline (12) arranged around the flexible spline (11); a first flange (21) coupled to the shaft (4) via a first bearing (31) and coupled to the flexible spline (11); and a second flange (22) coupled to the shaft (4) via a second bearing (32) and coupled to the circular spline (12), wherein one of the first and second flanges (21,22) is arranged near to the first end (401) of the shaft (4), and wherein a cavity (5) is provided between one of the first and second flanges (21,22) and the first end (401) of the shaft (4), and is in fluid communication with an external environment via the first through hole (403). According to the present disclosure, the lubricant leakage via the oil seals of the harmonic reducer (100) could be prevented effectively.