Strain Wave Gear Lubrication Using Hydrophobized Powder Films
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Solution Overview
Problem
Strain wave gearing efficiency decreases due to moisture-induced cohesion and particle aggregation of fine powders with layered crystal structures, leading to increased friction and torque loss, especially at high speeds.
Innovation Solution
Using a non-hydrophobized powder of an ionic crystalline compound with a layered crystal structure to form a strong lubricating film on contact surfaces initially, followed by enclosing a hydrophobized powder in the gearing's internal space to maintain lubrication and reduce cohesion, thereby minimizing efficiency drops and maintaining stable high-efficiency operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-hydrophobized powder of ionic crystalline compound is used as solid lubricant, then lubricating film formation is improved, but moisture absorption causes particle aggregation and efficiency decrease
Solution Approach 1:
The patent applies preliminary action by pre-treating the powder with hydrophobization before introducing it into the strain wave gearing. This surface modification is performed in advance to prevent moisture absorption and particle aggregation during operation, thereby maintaining both lubricating film formation capability and operational efficiency over time
Solution Approach 2:
The patent changes the surface property parameter of the powder from hydrophilic to hydrophobic through chemical treatment. This parameter change prevents moisture interaction, eliminating the cause of particle aggregation and efficiency degradation while preserving the lubricating film formation ability of the ionic crystalline compound
2Reliability
If fine powder is crushed and rolled between contact surfaces, then lubrication is improved, but torque loss increases during the process
Solution Approach 1:
The patent prepares the powder in advance by hydrophobizing the surface and controlling particle size distribution before introduction. This preliminary preparation ensures that the powder can be efficiently crushed and rolled into lubricating films without excessive torque loss, as the pre-treated powder requires less energy for deformation and positioning
3Stability of the object's composition
If hydrophobized powder is enclosed in internal space, then particle aggregation is reduced, but initial lubricating film strength is insufficient
Solution Approach 1:
The patent applies local quality by creating a dual-characteristic powder system where the surface is hydrophobic (for stability and dispersion) while the core maintains the ionic crystalline structure (for strong lubricating film formation). This localized differentiation of properties allows the powder to simultaneously resist aggregation and form strong lubricating 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
The method reduces efficiency losses and maintains stable high-efficiency operation over time with reduced heat generation by minimizing torque loss and particle aggregation, ensuring smooth rotation even at high speeds.
Implementation Method 1
the fine powder is crushed between contact surfaces to be lubricated, transferred to both contact surfaces to form a thin lubricating film
Implementation Method 2
a hydrophobized powder of the ionic crystalline compound having a layered crystal structure is then enclosed or packed in an internal space of the strain wave gearing
Implementation Method 3
an ionic crystalline compound having a layered crystal structure is used, moisture in the atmosphere forms in rows on the surfaces of the layered crystals due to hydrogen bonding
Data Source
Figure 1
Figure 2
AI summary
A strain wave gearing (1) is lubricated by a non-hydrophobized powder (10A) enclosed in an internal space (9) until the strain wave gearing is fully broken in, and the non-hydrophobized powder (10A) is transferred to contact surfaces of contact parts (B, C) to form a lubricating film. During operation under load, the strain wave gearing (1) is lubricated by a hydrophobized powder (10B) enclosed in the internal space (9) instead of the non-hydrophobized powder (10A). Each of the powders (10A, 10B) used is a powder of an ionic crystalline compound (MoS2, WS2, etc.) having a layered crystal structure. By lubricating the strain wave gearing (1) with the hydrophobized powder (10B) during operation under load, any temporary decrease in efficiency at the start of operation is minimized and stable operation of the strain wave gearing (1) can be maintained.