Planetary Gearbox Lubricant Tray With Variable Feed Nozzles

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Solution Overview

Problem

Existing planetary gear designs suffer from inhomogeneous lubricant distribution around the shaft circumference, leading to uneven lubrication of bearings and varying temperature behavior due to a single radial channel design, which is impractical to modify for uniform distribution.

Innovation Solution

The design incorporates feed nozzles with varying opening cross-sections based on their position relative to the shaft-side channel, ensuring equal lubricant distribution to each planetary pin and bearing by adjusting the flow cross-sections to compensate for inhomogeneous lubricant accumulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single radial channel is used on the shaft, then the shaft structure remains simple, but the lubricant distribution around the shaft circumference becomes inhomogeneous

Engineering Contradiction:
Improveshaft channel structureVSAvoidlubricant distribution uniformity
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by making each feed nozzle have a different opening cross-section according to its position around the shaft. Nozzles closer to the radial channel opening have smaller cross-sections, while those farther away have larger cross-sections. This local differentiation compensates for the inhomogeneous lubricant accumulation in the collecting chamber, ensuring uniform lubricant distribution to all planetary pins despite using a simple single radial channel structure.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If feed nozzles with different opening cross-sections are used, then homogeneous lubricant distribution is achieved, but the device complexity increases

Engineering Contradiction:
Improvelubricant distribution uniformityVSAvoidfeed nozzle structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent changes the geometric parameter of the feed nozzles by varying their opening cross-sections. Each nozzle's cross-section is specifically designed based on its angular position relative to the radial channel opening. This parameter variation allows the system to compensate for position-dependent lubricant accumulation differences, achieving homogeneous lubricant distribution to all planetary pins while maintaining a relatively simple overall structure.

Inventive Principle:
Principle #35Parameter changes

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

Achieves homogeneous lubrication of planetary pins and bearings despite inhomogeneous lubricant collection, maintaining consistent lubrication levels and reducing temperature variations.

Implementation Method 1

feed nozzles with varying opening cross-sections based on their position relative to the shaft-side channel, ensuring equal lubricant distribution to each planetary pin and bearing by adjusting the flow cross-sections to compensate for inhomogeneous lubricant accumulation

Methodology Applied
Scientific EffectFluid flow regulation through variable cross-section:

Implementation Method 2

a lubricant collecting tray having a collecting space for collecting the lubricant supplied via the shaft-side channel

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP4399421B1Planetary gearbox and lubricant-collecting tray for a planetary gearbox
Publication Date: 2025.07.09 SCHAEFFLER TECHNOLOGIES AG & CO KG
  • EP4399421B1 patent drawingFigure 1~2
  • EP4399421B1 patent drawingFigure 3

AI summary

The invention relates to a planetary gearbox comprising: a shaft (2) having a channel structure (3) which is provided for conducting lubricant and has a channel (5) opening into the outer face of the shaft (2); a planet carrier (6); at least two planetary pins (7) which are located on the planet carrier (6) and on which one planetary gear (9) each is mounted, wherein each planetary pin (7) has a channel structure (15) for conducting the lubricant to the bearing (8) of the planetary gear (9); a lubricant-collecting tray (12) which has a collection space (19), is provided for collecting the lubricant supplied via the shaft-side channel (5) and has at least two hollow feed nozzles (14) which each open into a planetary-pin-side channel structure (15) and are provided for conducting the lubricant into the relevant channel structure (15), wherein a feed nozzle (14) which is positioned, viewed in the circumferential direction, closer to the opening of the channel (5) has a smaller opening cross-section (Q1) than a feed nozzle (14) which is positioned further away.