Planetary Gear Oil Supply Layout for Pinion Lubrication
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Solution Overview
Problem
There is a need to increase the amount of lubricating oil introduced to specific locations within power transmission devices, particularly in the context of a power transmission device for an electric automobile with a bevel gear type differential mechanism and planetary gear mechanism.
Innovation Solution
The power transmission device incorporates a pinion gear with a large and small pinion gear, a carrier, a ring gear that engages with the small pinion gear, an oil supply unit positioned above the horizontal line passing through the revolution center of the pinion gear, and a downstream side wall part facing the gear surface of the large pinion gear, where the downstream side wall part is arranged adjacent to the oil supply unit in the revolution direction. This configuration allows for the efficient scooping and introduction of lubricating oil to the oil catch unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the oil supply unit is positioned above the horizontal line passing through the revolution center of the pinion gear, then the amount of lubricating oil introduced to the oil catch unit increases, but the structural complexity of the power transmission device increases
Solution Approach 1:
The patent utilizes the dynamic revolution motion of the pinion gear around its center to generate centrifugal force, which naturally directs the lubricating oil from the oil supply unit toward the oil catch unit. This dynamic approach eliminates the need for additional pumping mechanisms or complex delivery systems, thereby increasing oil quantity while avoiding excessive structural complexity
Solution Approach 2:
The downstream side wall part acts as an intermediary structure that guides and channels the lubricating oil from the oil supply unit to the oil catch unit. By positioning this wall part adjacent to the oil supply unit in the revolution direction, it facilitates oil flow without requiring complex delivery mechanisms, thus resolving the contradiction between oil quantity and structural complexity
2Reliability
If the downstream side wall part is arranged adjacent to the oil supply unit in the revolution direction of the pinion gear, then the lubricating oil flow to the gear surface is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent optimizes the positioning parameters of the downstream side wall part and oil supply unit based on the pinion gear's revolution characteristics. By carefully selecting the angular position and radial distance of these components relative to the revolution center, the design ensures reliable oil flow while maintaining manufacturable tolerance levels
Solution Approach 2:
The oil supply unit is positioned and configured in advance to take advantage of the pinion gear's upcoming revolution position. This preliminary arrangement ensures that when the pinion gear reaches the optimal position in its revolution cycle, the oil is already in position to be effectively delivered to the gear surface, improving reliability without requiring ultra-precise manufacturing
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 effectively increases the amount of lubricating oil introduced to the oil catch unit, ensuring adequate lubrication of the gear components and enhancing the operational efficiency and longevity of the power transmission device.
Implementation Method 1
the downstream side wall part is arranged to be adjacent to the oil supply unit further downstream in the revolution direction of the pinion gear than the oil supply unit when viewed from the axial direction
Data Source
AI summary
A power transmission device includes a pinion gear having a large pinion gear and a small pinion gear, a carrier that supports the pinion gear, a ring gear that engages with the small pinion gear, an oil supply unit positioned above a horizontal line that passes through a revolution center of the pinion gear, and a downstream side wall part facing a gear surface of the large pinion gear. The downstream side wall part is arranged to be adjacent to the oil supply unit further downstream in a revolution direction of the pinion gear than the oil supply unit when viewed from an axial direction.