Planetary Gear Lubrication Path Segmentation
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Solution Overview
Problem
In conventional planetary gear sets for automatic transmissions, lubrication oil supplied to the needle bearing is often heated by the thrust bearing before reaching it, resulting in inadequate lubrication support for both the thrust and needle bearings.
Innovation Solution
A planetary gear set design that includes a central shaft with a main lubrication path and penetration holes connecting to sun gear and pinion gear lubrication paths, with a sealing element to isolate these paths and prevent cross-contamination, ensuring efficient lubrication for each bearing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If lubrication oil is supplied through a common path to both thrust bearing and needle bearing, then the structure is simple, but the lubrication efficiency deteriorates because the oil is heated by the thrust bearing before reaching the needle bearing
Solution Approach 1:
The common lubrication path is segmented into separate paths: a first lubrication path supplies oil to the thrust bearing, while a second lubrication path supplies oil to the needle bearing. This segmentation prevents the lubrication oil from being heated by the thrust bearing before reaching the needle bearing, thereby maintaining lubrication efficiency while managing the complexity through structured division.
Solution Approach 2:
A sealing element is introduced as an intermediary component to prevent communication between the first and second lubrication paths. This sealing element ensures that lubrication oil flowing through the first path (heated by the thrust bearing) does not mix with or preheat the oil in the second path, thereby protecting the lubrication efficiency of the needle bearing.
2Ease of manufacture
If lubrication oil flows freely between thrust bearing and needle bearing paths, then the system is simple to manufacture, but the temperature control of lubrication oil deteriorates
Solution Approach 1:
The lubrication system is segmented into thermally isolated paths. The first lubrication path is dedicated to the thrust bearing and the second to the needle bearing, with thermal isolation achieved through the sealing element. This segmentation allows independent temperature management for each bearing, preventing heat transfer from the thrust bearing to the needle bearing lubrication oil.
Solution Approach 2:
The sealing element acts as a thermal intermediary that blocks heat transfer between the two lubrication paths. By preventing thermal communication between the first and second paths, the sealing element maintains appropriate temperature control for the needle bearing lubrication oil, preventing it from being overheated by the thrust bearing.
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 by maintaining the temperature and flow integrity of lubrication oil within each path, effectively supporting the rotation of both thrust and needle bearings.
Implementation Method 1
a sealing element disposed in a passageway connecting the pinion gear lubrication path and the sun gear lubrication path so as to close the passageway
Implementation Method 2
the lubrication oil for lubricating a needle bearing of a pinion gear is supplied to the needle bearing through a thrust bearing
Data Source
AI summary
A planetary gear set for an automatic transmission of a vehicle includes a central shaft having a main lubrication path and a penetration hole connected with the main lubrication path, a sun gear, a pinion gear, a ring gear, a planet carrier, a first bearing disposed between a side of the sun gear and the planet carrier, a second bearing disposed between the planet carrier and the pinion gear, a clutch hub shaft, a sun gear lubrication path that connects the main lubrication path to the first bearing through the penetration hole, a pinion gear lubrication path that connects the main lubrication path to the second bearing through the penetration hole, and a sealing element disposed in a passageway connecting the pinion gear lubrication path and the sun gear lubrication path so as to close the passageway.