Planetary Gearset Lubrication Cup Layout for Low-Speed Oil Control
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Solution Overview
Problem
Conventional epicyclic gear trains face challenges in lubricating the meshing zones and axes of satellite pinions, particularly at low rotational speeds, leading to oil buildup and excessive heating, which complicates maintenance and reliability due to the use of dynamic or rotating seals and complex oil routing networks.
Innovation Solution
An epicyclic gear train design with a divided annular cup having circumferentially separated troughs for distinct oil circuits, featuring openings in the annular wall to evacuate excess oil and notches for crenellated edges, allowing for efficient lubrication of contact zones and shafts without dynamic seals, and integrated oil projection means for radial oil supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single annular cup is used for both lubrication circuits, then the structure is simple, but oil flow cannot be properly managed leading to accumulation and overheating
Solution Approach 1:
The single annular cup is divided into two separate circumferential zones: a first zone for the first lubrication circuit and a second zone for the second lubrication circuit. This segmentation allows independent oil flow management for each circuit, preventing oil accumulation and overheating while maintaining a relatively simple overall structure.
2Reliability
If dynamic seals are used in oil passages, then lubrication can be provided, but maintenance complexity increases due to seal wear
Solution Approach 1:
The invention eliminates dynamic seals and rotating seals from the oil passage system by using a stationary annular cup with separate circumferential zones. Oil is distributed to the two lubrication circuits through this stationary structure, removing the wear-prone sealing components and significantly reducing maintenance complexity.
3Ease of operation
If oil flow rate is high at low rotational speeds, then lubrication coverage is improved, but oil accumulates in the cup causing overheating
Solution Approach 1:
By dividing the annular cup into two separate circumferential zones for different lubrication circuits, the invention enables independent oil flow management. Excess oil in each zone can be separately controlled and drained, preventing accumulation and overheating even when high oil flow rates are supplied at low rotational speeds.
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 design enhances lubrication efficiency, reduces maintenance complexity, and prevents oil splatter and overheating by effectively managing oil flow and pressure, improving the reliability and simplicity of gearbox lubrication systems.
Implementation Method 1
The oil is then collected by centrifugal force and subsequently directed to lubrication means for the gears
Implementation Method 2
the openings made in the portions of the wall laterally delimiting the second basins allow excess oil to drain through the openings
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to a planetary gearset (10) comprising 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 said planet fears being freely rotatably mounted on a planet carrier (32), the gearset (10) comprising an annular cup (56) rigidly connected to the planet carrier (36) and opening radially inwards. According to the invention, the cup (56) is divided into a circumferential series of first recesses (60) belonging to the first oil circuit and of second recesses (62) belonging to the second oil circuit, the first recesses (60) not being in fluid communication with the second recesses (62), and the cup (56) has two axially facing annular walls (56a, 56b), with the annular wall (56b) farthest from a median transverse plane (74) of the gearset (10) comprising apertures (76) opening out into the second recesses (62).