Planetary Gear Lubrication Passages for Mode-Switching Transmissions
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Solution Overview
Problem
The existing gear systems used in vehicles face challenges in smoothly lubricating the planetary gear assembly when the operation mode is changed between driving, neutral, and parking modes, leading to potential friction, wear, and noise due to interrupted lubrication passages between the carrier and output shaft.
Innovation Solution
A gear system design incorporating a sun gear, ring gear, planetary gear, and output shaft with strategically positioned lubrication passages, including a third circumferential passage that connects radial passages on the carrier and output shaft, ensuring continuous oil flow and lubrication regardless of the operation mode, thereby maintaining engagement and reducing friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the carrier and output shaft are selectively engaged to change operation modes, then the gear system can achieve driving mode, neutral mode, and parking mode, but the lubrication passage between carrier and output shaft may be interrupted, causing friction and wear
Solution Approach 1:
The lubrication passage is divided into multiple segments: a first lubrication passage in the carrier, a second lubrication passage in the output shaft, and a third lubrication passage in the circumferential groove. This segmentation allows each part to maintain lubrication independently, ensuring continuous lubrication even when engagement states change between different operation modes.
Solution Approach 2:
The third lubrication passage is formed within the circumferential groove that is part of the output shaft structure, creating a nested arrangement where the lubrication passage is embedded within the structural feature of the output shaft. This allows the lubrication system to be integrated into the existing engagement mechanism without adding separate components.
2Reliability
If a circumferential lubrication passage is added to connect radial passages, then continuous lubrication is ensured across all operation modes, but the device complexity increases
Solution Approach 1:
The circumferential groove on the output shaft serves dual purposes: it provides the structural feature for forming the third lubrication passage, and it acts as part of the engagement mechanism between the carrier and output shaft. This multi-functionality reduces the need for additional dedicated lubrication components, thereby limiting the increase in device complexity.
Solution Approach 2:
The lubrication passage structure is merged with the engagement structure by forming the third lubrication passage within the circumferential groove. This integration combines the lubrication function with the mechanical engagement feature, reducing the overall complexity compared to having separate independent lubrication systems.
Data Source
AI summary
A gear system is provided to secure lubrication passages when the gear system is changed between driving, neutral, and parking modes. The gear system includes a planetary gear assembly, a hollow portion output shaft selectively engaged with a carrier such that the output shaft is configured to rotate with the carrier when the output shaft is engaged with the carrier. The gear system further includes a first lubrication passage formed radially at a first point on the carrier, a second lubrication passage formed radially at a second point on the output shaft, and a third lubrication passage formed between the outer surface of the output shaft and the inner surface of the carrier and configured to connect the first lubrication passage and the second lubrication passage.