Planetary Gear Retainer Lubrication and Thrust Support
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Solution Overview
Problem
Planetary gear assemblies face challenges in robust design, lubrication, and packaging due to increasing power and torque requirements, high rotational speeds of planet gears, and the need for efficient lubrication to manage heat and ensure longevity in compact spaces.
Innovation Solution
The planetary gear set assembly includes a planet carrier with a backing and spider portion, thrust bearings, and a bearing plate with lubrication divots and passageways to facilitate pressurized hydraulic fluid distribution, ensuring adequate lubrication to the planet gears and minimizing the impact of high-speed rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If planetary gear assemblies are designed for higher power and torque requirements, then the power transmission capability is improved, but the packaging space required increases and the structural complexity increases
Solution Approach 1:
The bearing retainer plate is integrated into the planet carrier structure, with bearing bores formed directly in the carrier body. This nesting approach eliminates separate bearing housings and reduces the overall volume required for the planetary gear assembly while maintaining high power transmission capability through robust bearing support.
Solution Approach 2:
The patent combines the planet carrier and bearing retainer into a single integrated structure. The carrier body incorporates bearing bores, sealing surfaces, and lubrication passages directly, merging multiple functions into one component. This reduces the number of parts and packaging space while enhancing power transmission through optimized structural integrity.
2Speed
If planet gears rotate at high speeds, then the speed capability is improved, but sufficient lubrication becomes more difficult to maintain and heat generation increases
Solution Approach 1:
The bearing retainer plate serves as an intermediary structure that facilitates lubrication delivery to high-speed planet gears. It incorporates dedicated lubrication passages and bearing bores that ensure adequate lubricant flow to the gear-bearer interface even at high rotational speeds, maintaining reliability through improved lubrication architecture.
Solution Approach 2:
The patent incorporates hydraulic lubrication passages within the bearing retainer plate structure. Pressurized lubricant is delivered through these passages to the bearing interfaces, ensuring sufficient lubrication at high speeds where traditional splash or drip lubrication would be inadequate. This hydraulic approach controls lubricant delivery precisely to maintain reliability.
3Ease of manufacture
If the bearing retainer design is simplified, then the manufacturing ease is improved, but the robustness of the planetary gear assembly deteriorates
Solution Approach 1:
By merging the planet carrier and bearing retainer into a single cast or forged component, the patent achieves both manufacturing simplicity and structural robustness. The integrated structure eliminates multiple machining operations and assembly steps while creating a monolithic component with inherent structural strength to support high loads and speeds.
Solution Approach 2:
The bearing retainer plate is designed as a multi-functional component that provides bearing support, sealing surfaces, lubrication passages, and structural reinforcement. This universal design consolidates multiple functions into one component, simplifying manufacturing while enhancing overall assembly robustness through integrated functionality.
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 the robustness and longevity of planetary gear assemblies by providing effective lubrication pathways and thrust bearings, addressing the issues of high-speed rotation and compact packaging while maintaining efficient lubrication flow.
Implementation Method 1
a lubrication passageway for providing pressurized hydraulic fluid to lubricate the planet gears of the planet carrier assembly. The lubrication pathway includes an axial bore that intersects a radial bore in the second rotating member
Implementation Method 2
The first thrust bearing is disposed between the backing portion of the planet carrier assembly and the first axial end of the sun gear. The second thrust bearing is disposed between the bearing plate and the second axial end of the sun gear
Data Source
AI summary
A planetary gear set assembly for a transmission includes a planet carrier, a sun gear, a ring gear, a bearing plate, and a thrust bearing placed between the sun gear and the bearing plate. The bearing plate is retained by the planetary gear carrier and includes a plurality of lubrication features for providing a lubrication path from an input shaft through the thrust bearing and bearing plate to the pinion shafts.