Double-Walled Planetary Gear Lubrication for Leak Control
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Solution Overview
Problem
Planetary gears in wind turbines face challenges in efficient lubricant supply and leakage, leading to reduced performance and increased maintenance costs due to lubricant loss and wear, especially under increased operating loads.
Innovation Solution
A planetary gear design featuring a double-walled tube with an inner and outer tube forming an annular channel, a bushing for leak-free lubricant transfer, and a guide bearing to adjust the gap between the bushing and transmission components, minimizing lubricant loss and allowing increased load capacity, along with a bearing bushing for cost-effective and precise lubricant delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single-walled tube is used for lubricant supply, then the structure is simple, but lubricant leakage increases and delivery reliability deteriorates
Solution Approach 1:
The single-walled tube is segmented into a double-walled tube structure with an inner tube and an outer tube. The inner tube delivers lubricant while the outer tube provides structural support and sealing. This segmentation improves lubricant delivery reliability by creating a more robust system with distributed functions, while the modular nature keeps manufacturing complexity manageable.
Solution Approach 2:
The inner tube is nested within the outer tube, forming a concentric double-walled structure. The annular space between the tubes can be used for sealing or structural purposes. This nesting arrangement improves reliability by providing redundant pathways and enhanced sealing capability, while adding only moderate structural complexity.
2Reliability
If PTFE seals are used at the outlet point, then sealing is provided, but manufacturing complexity increases and durability decreases
Solution Approach 1:
The PTFE seal is extracted from the outlet point and replaced with a bushing that provides sealing through its structural design and gap control mechanism. This eliminates the need for separate sealing components, simplifying manufacturing while maintaining or improving sealing performance through the controlled gap between the bushing and transmission component.
Solution Approach 2:
The bushing acts as an intermediary element between the double-walled tube and the transmission component. It provides a controlled gap that allows lubricant passage while preventing excessive leakage, and its friction material enables durable, leak-inhibiting transfer of lubricant without requiring complex sealing arrangements.
3Quantity of substance
If the gap at the bushing is large, then lubricant flow is easy, but lubricant loss increases
Solution Approach 1:
The gap dimensions at the bushing are precisely controlled within specific ranges (e.g., 0.05-0.5mm radially) to optimize the balance between lubricant throughput and leakage. This parameter optimization ensures sufficient lubricant delivery to all planetary stages while minimizing loss, achieving both high quantity of substance delivery and low substance loss.
4Power
If the planetary gear is subjected to increased operating loads, then power transmission capacity improves, but lubricant supply efficiency deteriorates due to bending stresses disrupting the gap
Solution Approach 1:
The system is designed to dynamically adapt to increased operating loads. The double-walled tube structure provides enhanced mechanical strength to resist bending stresses, while the guide bearing maintains the bushing gap within acceptable ranges even under high loads. This dynamic capability allows the planetary gear to handle increased power while maintaining lubricant supply efficiency.
Solution Approach 2:
The bushing is made from friction materials or non-friction materials with high load-bearing capacity (such as bronze, steel alloys, cast iron, aluminum alloys, or fiber composite materials). These composite or specialized materials enable the bushing to maintain its gap and sealing function under increased operating loads, preventing disruption of lubricant supply while withstanding higher mechanical stresses.
5Ease of operation
If the guide bearing is positioned far from the bushing, then assembly is easier, but alignment precision and gap stability deteriorate
Solution Approach 1:
The guide bearing is preliminarily positioned in close proximity to the bushing during assembly design. This preliminary positioning ensures that the bushing gap is established with high precision from the outset, maintaining stable alignment even under operational loads. The close positioning may require slightly more complex assembly procedures, but ensures superior gap stability and alignment precision.
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 provides improved lubrication and cooling for transmission components, enhances the load capacity of planetary gears, and reduces maintenance costs by minimizing lubricant loss and wear, while allowing for efficient lubricant supply to multiple planetary stages.
Implementation Method 1
The inner and outer pipes form an annular channel for lubricating oil
Implementation Method 2
The bushing enables a low-leakage, almost leak-free, transfer of the lubricant to the transmission component
Implementation Method 3
the guide bearing...is designed to adjust a gap on the bushing
Implementation Method 4
improved lubrication and/or cooling can be achieved for transmission components
Data Source
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AI summary
The invention relates to a planetary transmission (10) comprising a first and a second planetary stage (20, 30), at least one transmission component (11) and a double-walled pipe (60). An outlet point (63) for dispensing lubricant (35) into the transmission component (11) is formed thereon in a central section (50). The double-walled pipe (60) is received in a guide bearing (45), a bushing (66) being arranged in the region of the outlet point (63), wherein a gap (80) is formed between the bushing (66) and the transmission component (11). The invention also relates to a drive train (81) having a generator (86) which is connected to a transmission (84) which is designed as the planetary transmission (10) according to the invention. The invention further relates to a wind turbine (90) which is provided with such a drive train (81). Furthermore, the invention relates to a computer program product (70), by way of which the operating behavior of such a planetary transmission (10) can be simulated.