Strain Wave Gear Lubricant Sealing With Textured Groove Surfaces
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Solution Overview
Problem
Existing lubricant sealing structures in strain wave gearings and other mechanical devices face challenges in maintaining sealing properties due to wear and leakage of lubricants, which can degrade the seal's effectiveness and lead to lubricant penetration into the seal portion, causing wear and reduced sealing efficiency.
Innovation Solution
A lubricant sealing structure is implemented using surface texturing with fine grooves on the oil-repellent and oil film formation surfaces, where the oil-repellent surface prevents lubricant leakage by forming a spheroidal shape and the oil film formation surface maintains a suitable oil film thickness, enhancing the seal's wear resistance and sealing efficacy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lubricant such as gear oil enclosed in the interior of a device penetrates and comes into contact with the seal portion, then the seal-lip grease film thickness decreases and wear increases, but the sealing properties and wear resistance of the seal portion decrease
Solution Approach 1:
The invention applies different surface treatments to different regions of the rotating member. The oil-repellent surface is formed on the portion that comes into contact with the lubricant in the gap, while the oil film formation surface is formed on the seal lip contact portion. This local differentiation allows each surface to perform its specific function: repelling lubricant where needed and maintaining grease film where sealing is critical.
Solution Approach 2:
The oil-repellent surface acts as an intermediary barrier between the lubricant in the gap and the seal portion. By repelling the lubricant, it prevents the lubricant from reaching and degrading the seal-lip grease film, thus protecting the sealing properties without directly interfering with the seal's operation.
2Reliability
If surface texturing with fine grooves is applied to prevent lubricant leakage, then sealing efficacy is enhanced, but manufacturing complexity increases
Solution Approach 1:
The invention replaces conventional mechanical surface treatment methods with laser surface texturing. The laser processing method allows for precise formation of fine grooves with controlled depth and spacing, achieving the desired oil-repelling and oil film formation effects without complex mechanical machining operations.
Solution Approach 2:
The invention optimizes specific parameters of the surface texturing, including groove depth (0.1-10 μm), groove spacing (10-100 μm), and groove cross-sectional shape, to achieve the desired balance between sealing performance and manufacturability. These parameter optimizations make the laser texturing process more controllable and efficient.
3Strength
If the seal-lip grease film thickness is maintained to prevent wear, then sealing properties are preserved, but lubricant penetration into the seal portion increases wear
Solution Approach 1:
The invention converts the potentially harmful effect of lubricant contact into a beneficial outcome. The oil-repellent surface is designed to actively repel lubricant, preventing it from reaching and degrading the seal-lip grease film. This transforms the lubricant from a harmful substance that causes wear into a contained element that does not interfere with the sealing function.
Solution Approach 2:
The oil-repellent surface is formed in advance on the rotating member before the seal operates. This preliminary surface treatment creates a protective barrier that prevents lubricant from reaching the seal portion, thereby preemptively protecting the grease film from degradation and wear.
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 lubricant sealing structure effectively prevents lubricant leakage and maintains the sealing properties by repelling lubricants and forming a high-rigidity oil film, reducing wear and ensuring reliable sealing, thus enhancing the seal's effectiveness and preventing lubricant penetration into the seal portion.
Implementation Method 1
an oil-repellent surface that is formed on at least one of the first surface portion and the second surface portion, and that is positioned at a side of the interior of the device with respect to the oil seal... the oil-repellent surface being provided with a surface texture in which first fine grooves are formed in a prescribed pattern so as to achieve an oil-repelling effect with respect to the lubricant
Implementation Method 2
an oil film formation surface formed on at least one of a distal-end surface portion of the oil seal that comes into contact with the second surface portion and a site on the second surface portion with which the distal-end surface portion comes into contact... the oil film formation surface being provided with a surface texture in which second fine grooves are formed in a prescribed pattern so as to achieve an oil film formation effect
Data Source
AI summary
A strain wave gearing has a lubricant sealing structure that prevents a lubricant from leaking to the outside through a gap portion between a hollow input shaft and an end plate. The lubricant sealing structure includes an oil-repellent surface formed on the surface portion facing the gap portion, an oil seal that seals the gap portion, and an oil film forming surface formed at a lip tip surface of the oil seal. The oil-repellent surface has a surface texture in which first fine grooves are formed in a predetermined pattern so that an oil-repellent effect can be obtained with respect to the lubricant. The oil film forming surface has a surface texture in which second fine grooves are formed in a predetermined pattern so that an oil film forming effect of a seal lip grease can be obtained.