Asymmetric Gear Surface Patterns for Lubrication Retention
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Solution Overview
Problem
Gear devices in robots, such as wave gear devices, face issues with insufficient lubrication leading to early burning and wear due to the deceleration mechanism, which affects the longevity of the gear components.
Innovation Solution
A gear device configuration featuring a first surface with a tubular shape and a second surface also in a tubular shape, both disposed inside and outside each other, with alternating recessed and projection portions forming distinct uneven patterns to reduce lubricant spillage and maintain effective lubricity over time, thereby extending the gear device's lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solid lubricant is fixed to the inner circumferential surface of the external gear, then lubrication of the friction-contact portion is improved, but lubricant spillage occurs when projections enter recessed portions, reducing long-term lubricity
Solution Approach 1:
The invention applies asymmetry by creating non-symmetric uneven patterns on the contact surfaces. The first surface has a first uneven pattern and the second surface has a second uneven pattern that is different from the first pattern. This asymmetric configuration prevents projections from one surface from entering recessed portions of the other surface, thereby preventing lubricant spillage while maintaining effective lubrication contact.
2Productivity
If the gear device operates with repeated contact and separation of surfaces, then driving force transmission is achieved, but lubrication deteriorates due to lubricant spillage from recessed portions
Solution Approach 1:
By configuring the first uneven pattern and second uneven pattern to be different from each other, the invention prevents the cyclic entry of projections into recessed portions during repeated contact and separation operations. This maintains lubricant retention in the recessed portions throughout the operational cycle, ensuring long-term lubrication durability while maintaining driving force transmission capability.
3Ease of manufacture
If smooth contact surfaces are used, then manufacturing is easier, but lubricant retention is poor leading to early burning and wear
Solution Approach 1:
The invention applies local quality by creating localized uneven patterns (recessed portions and projection portions) on specific areas of the contact surfaces. These localized structures serve to retain lubricant at the friction-contact portions, providing excellent lubrication and preventing burning and wear, while the overall manufacturing process remains relatively simple through conventional surface treatment methods.
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 configuration effectively reduces lubricant spillage and maintains good lubricity between the surfaces, leading to a longer lifespan of the gear device by minimizing the entry of projections into recessed portions and facilitating lubricant retention, thus preventing premature damage.
Implementation Method 1
In order to lubricate a friction-contact portion of the external gear and the wave generator, a solid lubricant is fixed to a portion of an inner circumferential surface of the external gear, which is in the vicinity of the contact portion.
Data Source
AI summary
A robot includes a gear device that has a first surface and a second surface which are in a tubular shape around an axis, are disposed inside and outside of each other, and repeatedly come into contact with and separate away from each other with operation of the gear device. The first surface has a first recessed portion and a first projection portion, which extend in a direction having a circumferential direction component around the axis and configure a first uneven pattern, by being alternately arranged in a direction along the axis. The second surface has a second recessed portion and a second projection portion, which extend in the direction having the circumferential direction component around the axis and configure a second uneven pattern that is different from the first uneven pattern, by being alternately arranged in the direction along the axis.