Planetary Gear Lubrication Passage for Balanced Bearing Flow
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Solution Overview
Problem
The existing lubrication systems for planetary gears in powertrains face imbalances in lubricant distribution between the sun gear and planet gear bearings due to varying rotational speeds, leading to inadequate lubrication and a pumping effect, which can cause inefficiencies and wear.
Innovation Solution
A lubrication system with a flow restrictor is introduced, featuring a first passage part with a second outlet opening closer to the sun gear's rotation axis, allowing a predetermined proportion of lubricant to be directed to the sun gear and the remaining to the planet gear bearings, reducing the pumping effect and ensuring balanced lubricant flow across different operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single lubrication passage is used, then the structure is simple, but a pumping effect occurs causing imbalance in lubricant distribution
Solution Approach 1:
The lubrication passage is divided into multiple passage parts (first passage part extending from inlet to first outlet, second passage part with second outlet, third passage part to engagement area) rather than using a single continuous passage. This segmentation eliminates the pumping effect by creating independent flow paths that can be optimized for different destinations, ensuring balanced lubricant distribution to both the sun gear and planet gear bearings.
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 ensures consistent and balanced lubricant distribution to both the sun gear and planet gear bearings, reducing wear and improving operational efficiency across varying rotational speeds.
Implementation Method 1
The flow restrictor delimits a gap, having a third cross-sectional area, between an interior surface of the first passage part and the restrictor
Implementation Method 2
the lubricant is forced radially outwardly through the lubrication passage by means of the rotation of the planet gear carrier
Data Source
Figure 1~2
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AI summary
A lubrication system for a planetary gear (7) comprising a sun gear (9) rotationally fixedly arranged on a first shaft (14), a number of planet gears (11) rotatably supported by planet gear bearings (21) and a planet gear carrier (12) rotationally fixedly arranged on a second shaft (15). The lubrication system comprises a lubrication passage (35) adapted to direct lubricant from one of the shafts (14,15) to the planet gear bearings (21). The lubrication passage (35) comprises a first passage part (38) extending through the planet gear carrier (12) from an inlet opening (39) to a first outlet opening (40). The first passage part (38) further comprises a second outlet opening (41) adapted to direct lubricant to an engagement area (25) between the sun gear (9) and the planet gears (11). The second outlet opening (41) is located at a shorter radial distance from a rotation axis (18) of the sun gear (9) than the first outlet opening (40) and a flow restrictor (60) is arranged in the first passage part (38)between the first opening (40) and the second opening (41).