Floating Bushing Media Transfer in Planetary Transmissions
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Solution Overview
Problem
Current planetary transmissions face challenges in efficiently distributing lubricant and coolant due to limited installation space and high power density, making it difficult to achieve low-leakage distribution, especially with relative movements between rotating components.
Innovation Solution
A transfer device with an annular groove and peripheral bores on rotating transmission parts, utilizing a floating bush with sealing grooves and rings to facilitate low-leakage transfer of lubricant/coolant, allowing for radial and axial movements, and compatible with hybrid drives and multi-stage transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a compact planetary transmission with high power density is used, then the transmission size is reduced and power density is increased, but the installation space for supply media distribution is limited and leakage increases
Solution Approach 1:
The bushing is nested within the transmission structure, with sealing rings positioned within grooves on the bushing surface. This nested arrangement allows the supply media distribution system to be integrated within the compact transmission housing without requiring additional external space, thereby maintaining high power density while enabling reliable lubricant and coolant distribution.
Solution Approach 2:
The bushing acts as an intermediary component between the rotating and stationary parts of the transmission. It provides a controlled interface for supply media transfer, with sealing rings preventing leakage at the interface. This mediator structure enables reliable supply media distribution in the compact high power density transmission where direct connection between rotating and stationary parts would be insufficient.
2Ease of operation
If fixed and rotating components have relative movement, then the transmission can operate, but supply media distribution becomes impossible from a certain radial and axial relative movement
Solution Approach 1:
The bushing is designed with floating capability, allowing it to dynamically adjust its position radially and axially relative to the sealing grooves during transmission operation. This dynamic adaptation enables the bushing to maintain proper sealing contact despite the relative movements between rotating and stationary components, ensuring continuous supply media distribution while the transmission operates normally.
Solution Approach 2:
The sealing rings function as flexible sealing elements that can accommodate radial and axial movements between the bushing and sealing grooves. These flexible sealing components maintain their sealing effect despite relative displacement, allowing the transmission to operate with necessary component movement while preserving supply media distribution reliability.
3Reliability
If sealing rings are used to prevent leakage, then supply media distribution reliability is improved, but friction and wear increase
Solution Approach 1:
The supply media (lubricant and coolant) themselves are utilized to provide hydrodynamic lubrication between the sealing rings and the sealing grooves. This hydraulic film reduces direct metal-to-metal contact and minimizes friction and wear, while the sealing rings continue to prevent leakage effectively. The system uses the fluid being transported to protect the sealing components from wear.
Solution Approach 2:
The sealing system is self-lubricating through the supply media that flows through the transmission. The lubricant and coolant automatically lubricate the sealing ring interfaces without requiring external lubrication systems, reducing wear while maintaining sealing effectiveness. The system serves itself by using its own operational fluid to protect its sealing components.
4Reliability
If known distribution systems like double pitch tube system are used, then supply media can be distributed, but they cannot be used in planetary transmissions with hybrid drives and directly connected generators
Solution Approach 1:
The bushing-based supply media distribution system is designed as a universal solution that can be applied to various transmission configurations including conventional planetary transmissions, hybrid drives, and systems with directly connected generators. The floating bushing mechanism adapts to different operational conditions and mounting arrangements, providing versatile applicability across multiple transmission types without requiring system-specific design modifications.
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
Enables efficient, low-leakage transfer of lubricant/coolant across rotating and fixed systems, reducing leakage and wear, suitable for high-power density applications, including wind turbines, with a compact and cost-effective design.
Implementation Method 1
a respective sealing ring is arranged in the sealing grooves
Data Source
AI summary
A planetary transmission includes a transfer device for transferring a supply medium. First and second transmission parts rotate relative to one another, with the transfer device having an annular groove on a surface of the first transmission part or of the second transmission part. The transfer device has bores distributed over a periphery. The first transmission part includes a separate bush which points towards the second transmission part and has a sealing groove with a sealing ring axially on both sides of the annular groove. The bush is arranged rotationally fixed on a rest of the first transmission part and designed to float in an axial direction with sufficient play in order to tilt out of a coaxial relative position with respect to the first transmission part and/or to the second transmission part to the extent of a relative movability of the respective sealing ring within the associated sealing groove.