Planet Gear Cooling Passage for Lubricant Agitation Heat
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Solution Overview
Problem
In planetary gear systems, residual lubricant agitation degrades power transmission efficiency and elevates lubricant temperature, making it difficult to cool and reuse the lubricant effectively as a heat transfer medium.
Innovation Solution
The implementation of a cooling passage within the planet gear with a coolant inlet and outlet, along with a coolant collection groove and distribution channel, allows for efficient coolant circulation and cooling, addressing lubricant agitation issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sufficient lubricant is supplied to reduce friction and provide wear protection, then lubrication effectiveness is improved, but lubricant temperature elevation occurs due to residual lubricant agitation
Solution Approach 1:
The patent extracts the cooling function from the lubrication system by introducing a separate coolant circulation system with cooling passages in the housing and planet gears. This allows the lubricant to perform its primary lubrication function while a dedicated cooling medium removes heat through the extraction of thermal energy via the coolant flow paths.
Solution Approach 2:
The patent introduces coolant as an intermediary substance that mediates heat transfer from the lubricant and gear components. The coolant circulates through cooling passages in the housing and planet gears, absorbing heat from the lubricant and gear surfaces, thereby indirectly cooling the lubricant without interfering with its lubrication function.
2Productivity
If residual lubricant is not removed completely, then continuous agitation occurs, but power transmission efficiency degrades and cooling becomes more difficult
Solution Approach 1:
The patent replaces the mechanical approach of removing residual lubricant through gear design modifications with a thermal approach using coolant circulation. Instead of attempting to eliminate residual lubricant mechanically, the system substitutes a cooling mechanism that manages the thermal consequences of residual lubricant agitation, thereby maintaining power transmission efficiency while addressing the cooling challenge.
Solution Approach 2:
The patent changes the thermal parameters of the system by introducing coolant flow that absorbs and removes heat generated by residual lubricant agitation. By controlling coolant flow rate and temperature, the system maintains optimal operating temperatures despite the continuous agitation of residual lubricant, thus preserving power transmission efficiency.
3Temperature
If cooling passages are added to the planet gear, then cooling efficiency is improved, but device complexity increases
Solution Approach 1:
The patent merges the cooling function with the existing planet gear structure by integrating cooling passages directly into the planet gear body. This consolidation combines the structural and thermal management functions into a single component, improving cooling efficiency while minimizing the increase in device complexity through functional integration.
Solution Approach 2:
The planet gear is designed with multi-functionality, serving both as a mechanical transmission element and as a heat dissipation component. The cooling passages integrated into the planet gear allow it to perform dual functions: power transmission through gear meshing and thermal management through coolant circulation, thereby improving cooling efficiency without proportionally increasing structural complexity.
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 and cooling efficiency, improving power transmission by effectively removing waste heat and maintaining lubricant effectiveness for repeated use.
Implementation Method 1
The planet gear has a cooling passage formed therein. The cooling passage may have a coolant inlet opened onto an inner surface of the planet gear and a coolant outlet opened onto a lateral surface of the planet gear.
Implementation Method 2
The lubricant is also a medium for conducting waste heat away from the planetary gear system.
Data Source
AI summary
A planetary gear system is disclosed. The planetary gear system includes a carrier, a planet gear defining a central planet axis, a pin coupling the planet gear to the carrier and a bearing disposed between the planet gear and the pin. The bearing includes a plurality of rolling elements. Each of the rolling elements is in contact with an inner race and an outer race. The planet gear has a formed therein cooling passage for allowing a coolant to pass therethrough to cool the planet gear.