Planetary Transmission Lubrication with Double-Walled Pipe and Bushing Gap
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Solution Overview
Problem
Existing planetary transmissions suffer from lubricant leakage and inefficiencies, which affect performance, reliability, and economy, particularly in applications like wind turbines.
Innovation Solution
A planetary transmission with a double-walled pipe and a bushing at the outlet point, combined with a pilot bearing, minimizes lubricant leakage through a controlled gap, allowing efficient lubrication and cooling of transmission components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single-walled pipe is used for lubricant supply, then the structure is simple, but lubricant leakage occurs and throughput is insufficient
Solution Approach 1:
The pipe is divided into two concentric walls (inner pipe and outer pipe) forming an annular duct, separating the lubricant flow path from the external environment. This segmentation prevents leakage while maintaining structural integrity and allows independent optimization of each wall's function.
Solution Approach 2:
The inner pipe is nested within the outer pipe, with the annular duct formed between them serving as the lubricant conduit. This nested configuration provides leakage prevention through dual-wall containment while minimizing space utilization and maintaining compact structure.
2Productivity
If lubricant throughput is increased to improve cooling and lubrication, then transmission performance improves, but lubricant loss increases
Solution Approach 1:
The outlet point is designed to intentionally allow controlled lubricant escape in the form of a spray pattern. This converts potential harmful leakage into a beneficial cooling and lubrication mechanism, where the sprayed lubricant directly contacts transmission components (planet gears, bearings) to enhance cooling efficiency and reduce friction.
Solution Approach 2:
The rotating motion of the planet gears periodically interrupts the lubricant flow from the outlet point, creating a pulsating spray pattern. This periodic action enhances lubricant distribution across the transmission components, improving both cooling and lubrication effectiveness while controlling overall consumption.
3Reliability
If seals made of PTFE are used at the outlet point, then lubricant containment is improved, but manufacturing complexity and cost increase
Solution Approach 1:
Instead of trying to completely seal the outlet point to prevent lubricant escape, the design inverts the approach by intentionally creating an open outlet that allows controlled spray. This inversion transforms the containment problem into a controlled distribution system, simplifying manufacturing while achieving effective lubrication and cooling.
4Loss of substance
If the bushing gap is minimized to reduce lubricant leakage, then containment improves, but manufacturing precision requirements increase
Solution Approach 1:
The design changes the operational parameters of the gap by utilizing the rotating motion of planet gears to create a dynamic spray pattern. Instead of minimizing the gap to eliminate leakage, the gap is optimized to allow controlled lubricant escape that becomes beneficial through rotation-induced atomization and distribution.
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 enhances lubricant throughput, reduces wear, and increases the operating load capacity of the transmission, enabling more powerful and cost-effective operation with reduced maintenance.
Implementation Method 1
In addition, the planetary transmission in the region of the outlet point, in the central portion, has a pilot bearing which is configured to set a gap on the bushing
Implementation Method 2
The bushing enables a low-leakage, almost leak-free transfer of the lubricant to the transmission component
Implementation Method 3
The inner pipe and the outer pipe form an annular duct for lubricating oil
Implementation Method 4
improved lubrication and/or cooling can thus be achieved for transmission components, for example for friction bearings of planet gears or spray lubrication of toothings
Data Source
AI summary
A planetary transmission includes first and second planetary stages. At least one of the first and second planetary stages includes a transmission component. The planetary transmission further includes a pilot bearing, and a double-walled pipe received in the pilot bearing and having a central portion designed to have an outlet point for dispensing lubricant into the transmission component. A bushing is disposed in a region of the outlet point such that a gap is formed between the bushing and the transmission component.