Wind Turbine Gearbox Lubrication with Gravity-Fed Dual Oil Levels
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Solution Overview
Problem
Wind turbine drive trains with two-stage gearboxes face challenges in lubrication, particularly when auxiliary power is not available, as the oil level in the gearbox sump is limited by the sealings, preventing adequate lubrication of all components.
Innovation Solution
A lubrication system with a two-stage gearbox design, where the second stage has a higher internal oil level than the first, utilizing a supply passage driven by gravity to distribute oil from the first stage to the second, and a backflow channel to manage excess oil, ensuring lubrication across all components, including a deflection device and overflow mechanism, and an oil reservoir with valves for off-grid operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the oil sump level is increased to provide adequate lubrication, then the lubrication coverage is improved, but the sealing effectiveness deteriorates due to oil leakage past the seals
Solution Approach 1:
The gearbox is divided into two separate stages with different oil levels. The first stage has a lower oil level limited by the seal, while the second stage has a higher oil level that provides adequate lubrication coverage. A separation wall with a controlled supply passage connects the two stages, allowing oil to flow from the first stage to the second stage without compromising the sealing at the input shaft.
2Reliability
If a two-stage gearbox design is implemented to provide different oil levels, then the lubrication effectiveness is improved, but the device complexity increases
Solution Approach 1:
The separation wall serves multiple functions simultaneously: it separates the two stages to maintain different oil levels, provides a controlled supply passage for oil flow from the first stage to the second stage, and acts as a structural support element. This merging of functions reduces the need for additional separate components and minimizes overall system complexity.
3Use of energy by moving object
If gravity-driven oil flow is used from first stage to second stage, then the energy consumption is reduced, but the oil flow control becomes more difficult
Solution Approach 1:
The supply passage acts as an intermediary element that controls oil flow from the first stage to the second stage. By designing the passage with specific dimensions, orientation, and flow resistance characteristics, the system achieves both energy-efficient gravity-driven flow and adequate flow control to ensure proper lubrication in the second stage without requiring additional active control mechanisms.
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
Ensures consistent and adequate lubrication of the drive train components during off-grid conditions, maintaining gearbox performance and extending maintenance intervals by utilizing gravity-driven oil distribution and a self-regulating fluid loop.
Implementation Method 1
The oil in the supply passage can be driven only by gravity from the first stage to the second stage of the gearbox
Data Source
AI summary
A lubrication system for a drive train of a wind turbine including a gearbox is provided. The gearbox has a first stage with a first internal oil level and a second stage with a second internal oil level. The second internal oil level is at a geodetic higher level than the first internal oil level. The gearbox further includes a supply passage for supplying oil from the first stage to the second stage of the gearbox.