Planetary Gear Carrier Oil Channels for Sun Gear Cooling
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Solution Overview
Problem
Planetary gear systems in vehicle transmissions generate significant heat due to friction between the sun gear and pinion gears, which can reduce the system's lifetime and efficiency.
Innovation Solution
The planetary gear system incorporates a carrier with oil passageways that direct oil onto the pinion gears, which then lubricate the sun gear, providing continuous oil cooling and reducing friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If pinion gears are engaged with the sun gear to transmit torque, then torque transmission capability is improved, but friction and heat generation increase, reducing system lifetime
Solution Approach 1:
The patent applies preliminary action by delivering oil to the pinion gear teeth before they engage with the sun gear teeth. The oil delivery channels are positioned to supply lubricant to the pinion gears in advance, ensuring that the gear surfaces are already lubricated when contact occurs, thereby reducing friction and heat generation from the start of engagement
Solution Approach 2:
The patent uses oil as an intermediary substance between the pinion gears and sun gear. The lubricating oil acts as a mediator that reduces direct metal-to-metal contact, minimizing friction and heat generation while allowing torque transmission to continue. This intermediary layer protects the gear surfaces and extends system lifetime
2Device complexity
If conventional lubrication methods are used, then device complexity is kept low, but insufficient cooling and lubrication occur at high speeds, limiting torque capacity
Solution Approach 1:
The patent segments the lubrication system by providing multiple separate oil delivery channels (first, second, third, and fourth channels) that target different regions of the pinion gears. This segmentation allows oil to be delivered to specific areas where friction occurs, improving lubrication effectiveness without requiring a completely complex new system architecture
Solution Approach 2:
The patent delivers oil in the radial direction toward the pinion gear teeth, which is perpendicular to the rotational axis. This dimensional approach allows lubricant to be delivered directly to the contact surfaces from a different orientation, improving cooling and lubrication effectiveness at high speeds while maintaining relatively simple device structure
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 solution enables increased torque at higher speeds compared to conventional planetary gear systems, while also extending the system's lifetime by reducing heat generation and friction.
Implementation Method 1
The carrier includes an oil delivery channel that delivers oil to the pinion gear
Implementation Method 2
The plurality of pinion gears may generate friction when engaged with the sun gear, thereby generating heat... the sun gear is lubricated with the oil
Implementation Method 3
when the pinion gear meshes with the sun gear, the sun gear is lubricated with the oil to provide continuous oil cooling of the sun gear
Data Source
Figure 1
Figure 1A
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AI summary
A planetary system, which may be found in an automotive transmission, is provided. The planetary system may include a sun gear, a plurality of pinion gears that are operably coupled to the sun gear and carried by a carrier, and a ring gear operably coupled to the plurality of pinion gears. The carrier may include a plurality of spaced apart side walls and a plurality of circumferentially spaced apart posts that interconnect the side walls. The plurality of posts and side walls may be unitary with one another. Further, at least one of the posts may include an oil delivery channel and an oil exit channel in fluid communication with one another.