Planetary Gearset Lubrication Through a Rotating Oil Cup
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Solution Overview
Problem
In small-diameter turbomachines, the radial space between the inner periphery of the cup and the shaft is insufficient to accommodate conventional lubrication systems, leading to challenges in lubricating the meshing zones and axes of satellite pinions, which results in wear and maintenance issues with dynamic joints.
Innovation Solution
An epicyclic gear train assembly with a central pinion integral to a shaft, featuring fixed oil projection means that direct oil towards deflection means attached to the shaft, allowing initial centrifugation and increased pressure, enabling effective lubrication despite limited radial space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lubrication systems with dynamic joints are used, then the meshing zones and axes can be lubricated, but the system becomes complex and requires regular maintenance due to wear of dynamic joints
Solution Approach 1:
The invention extracts and eliminates the dynamic joints from the lubrication system by using a fixed nozzle mounted on the stator structure that projects oil directly into the rotating cup. This removes the wear-prone dynamic sealing components while maintaining effective lubrication delivery to the satellite pinions.
Solution Approach 2:
The rotating cup acts as an intermediary component between the fixed nozzle and the lubrication points. It receives oil from the fixed nozzle and distributes it to the meshing zones and axes of the satellite pinions through centrifugal force, eliminating the need for dynamic joints while ensuring proper lubrication.
2Volume of moving object
If the radial space between the cup and shaft is reduced for compact design, then the turbomachine size is reduced, but conventional lubrication systems cannot be accommodated
Solution Approach 1:
The invention changes the spatial arrangement by mounting the nozzle on the stator structure (fixed dimension) rather than on the rotating shaft, and using the rotating cup to bridge the radial gap. This dimensional reconfiguration allows effective lubrication in reduced radial spaces without requiring complex dynamic joints.
Solution Approach 2:
The cup is designed to rotate with the shaft and replicate its rotational motion, allowing it to be positioned in the limited radial space between the shaft and the outer structure while still receiving oil from the fixed nozzle and distributing it effectively through centrifugal force.
3Reliability
If fixed nozzle configuration is used, then dynamic joints are eliminated, but sufficient radial space is required to project oil directly to the cup
Solution Approach 1:
The invention makes the cup dynamic by mounting it on the rotating shaft, allowing it to rotate with the shaft and use centrifugal force to receive and distribute oil. This dynamic configuration allows the cup to be positioned in limited radial space while maintaining effective oil projection from the fixed nozzle without requiring dynamic joints.
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 configuration enhances oil circulation and lubrication efficiency within the planet carrier, reducing wear and maintenance needs by increasing oil pressure and ensuring reliable lubrication in tight spaces.
Implementation Method 1
When the shaft is an input shaft such as a turbine shaft, its speed is greater than that of the planet carrier which forms an output of the gear train. The projection of oil towards the deflection means allows an initial centrifugation of the oil on the shaft, which increases its pressure compared to the prior art.
Data Source
Figure 1A
Figure 1B
AI summary
The invention relates to an assembly comprising a planetary gearset (10) having a sun gear (26), an outer gear (28) and planet gears (32) meshing with the sun gear (26) and with the outer gear (28), each of the planet gears being freely rotatably mounted on a planet carrier (32), wherein the sun gear (26) surrounds a shaft (24) to which it is connected such that it rotates therewith, and the gearset has means for lubricating the toothing and pins (34) of the planet gears (32), which means comprise an annular cup (56) rigidly connected to the planet carrier (36) and opening radially inwards. According to the invention, the assembly comprises stationary oil-spraying means (64) configured to spray oil towards means (70) for deflecting the oil into the annular cup (56).