Strain Wave Gear Shielding to Prevent Grease Dry-Out
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Solution Overview
Problem
The service life of tension shaft transmissions is limited due to lubricating grease drying out from contact with the shaping means, leading to reduced lubrication effectiveness and potential barriers preventing grease flow, which results in frictional heat and dehydration of the grease.
Innovation Solution
A contact prevention means, such as a shield, is implemented to prevent direct contact between the lubricating grease in the reservoir and the shaping means and bearing inner ring, ensuring continuous lubrication by maintaining the grease within the reservoir and preventing dehydration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the shaping means is placed in direct contact with the lubricating grease in the reservoir, then the grease can be easily supplied to the bearing, but the grease dries out due to frictional heat and contact with the high-speed rotating shaping means
Solution Approach 1:
A shield is introduced as an intermediary component between the shaping means and the lubricating grease. The shield prevents direct contact between the high-speed rotating shaping means and the grease, eliminating the drying out effect while still allowing grease to be supplied to the bearing through controlled pathways in the shield structure.
2Speed
If the shaping means rotates at high speed relative to the lubricating grease, then the transmission can operate, but frictional heat causes dehydration of the grease
Solution Approach 1:
The shield acts as a physical barrier that separates the high-speed rotating shaping means from the lubricating grease. This intermediary structure allows the shaping means to rotate at high speed without directly contacting the grease, thereby preventing frictional heating and the subsequent loss of base oil through evaporation.
Solution Approach 2:
The shield functions as a thin film or barrier structure that isolates the grease from the rotating shaping means. This thin barrier prevents the harmful thermal effects while maintaining the operational speed requirements of the transmission.
3Quantity of substance
If dried-out portions of lubricating grease remain in the reservoir, then space is occupied, but these portions act as barriers preventing grease flow to lubrication points
Solution Approach 1:
The shield prevents the formation of dried-out grease portions by eliminating direct contact between the grease and the high-speed rotating shaping means. By maintaining a separation, the shield ensures that the grease remains in its functional state and can freely flow to all lubrication points without being blocked by dried residues.
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
This solution extends the service life of tension shaft transmissions by maintaining an uninterrupted and sufficient lubrication supply, preventing grease dehydration and ensuring reliable operation by avoiding direct contact that causes frictional heat and lubrication failures.
Implementation Method 1
parts of the lubricating grease stored in the reservoir dry out over the service life of the transmission... it is disadvantageous in several respects if parts of the lubricating grease stored in the reservoir dry out... these heavily dried portions impede the flow of the not yet dried portion of lubricating grease... dried-up parts act like a barrier... permanent contact of a layer of lubricating grease with the shaping agent, which moves at high rotational speed relative to the lubricating grease arranged in the reservoir. Due to this constant contact and the resulting frictional heat, the aforementioned dehydration occurs
Data Source
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AI summary
The invention relates to a stress wave drive comprising a circular spline, a flex spline, and a wave generator, which includes a bearing and a forming element rotatably mounted relative to the flex spline by means of the bearing and which forms the bearing and/or the flex spline into a shape other than a circle, and a reservoir containing lubricating grease located directly adjacent to the bearing. The stress wave drive is characterized by the presence of a contact-prevention device, in particular a shield, which prevents direct contact between the lubricating grease in the reservoir and the forming element.