Inner Spline Tooth Geometry for Clean Lubricant Drainage

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing spline coupling lubrication systems face issues with drainage holes having minimum diameters that are too great, leading to sharp edges or oval-shaped apertures due to drilling constraints, which can result in inefficient lubricant evacuation and operational issues.

Innovation Solution

The design incorporates female spline teeth with varying tooth heights, where one or more teeth have a reduced height to accommodate drainage holes that terminate at a wider top land surface, ensuring efficient lubricant evacuation without sharp edges or partial drilling into the tooth flanks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If drainage holes are drilled through female spline teeth, then lubricant evacuation is enabled, but the minimum hole diameter creates sharp edges or oval-shaped apertures

Engineering Contradiction:

Improvelubricant evacuation efficiencyVSAvoidaperture shape accuracy

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by creating a specific structural feature (reduced tooth height at selected locations) to provide a localized platform for drainage hole placement. This allows the drainage holes to be positioned on wider top land surfaces rather than through the full tooth structure, enabling proper hole geometry without compromising the overall spline tooth integrity.

Inventive Principle:

Principle #3Local quality

2Reliability

If drainage holes are drilled through female spline teeth, then lubricant evacuation is enabled, but drilling constraints prevent proper hole formation

Engineering Contradiction:

Improvelubricant evacuation efficiencyVSAvoiddrilling operation feasibility

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by pre-forming reduced height sections in the female spline teeth before the drainage hole drilling operation. This preparatory step creates favorable conditions for subsequent drilling by providing adequate top land surface area, thereby eliminating drilling constraints and enabling proper hole formation without manufacturing difficulties.

Inventive Principle:

Principle #10Preliminary action

3Ease of manufacture

If all female spline teeth have uniform height, then manufacturing is simplified, but drainage holes cannot be properly accommodated on top land surface

Engineering Contradiction:

Improvetooth uniformityVSAvoiddrainage hole placement

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies local quality by creating specific reduced height features at selected female spline tooth locations while maintaining uniform height at other locations. This allows drainage holes to be properly accommodated on the wider top land surfaces of the reduced height teeth, while the majority of teeth retain their standard dimensions for normal engagement.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent applies asymmetry by intentionally creating non-uniform tooth heights at specific locations within the otherwise symmetric spline structure. This asymmetric modification provides dedicated spaces for drainage hole placement without affecting the symmetric engagement characteristics of the majority of spline teeth.

Inventive Principle:

Principle #4Asymmetry

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 approach allows for effective lubricant drainage through drainage holes that are fully accommodated on the top land surface, preventing sharp edges and ensuring consistent, efficient lubricant circulation and evacuation within the spline coupling.

Implementation Method 1

evacuating the lubricating fluid through at least one or more drainage holes in a top land surface and through at least one or more of the plurality of female spline teeth

Methodology Applied

Scientific EffectFluid flow through drilled hole:

Data Source

PatentUS11739795B2Inner spline with top land drainage hole

Publication Date: 2023.08.29 PRATT & WHITNEY CANADA CORP

AI summary

A spline coupling comprises a male spline member having male spline teeth and a female spline member having female spline teeth complementary to and engaged with the male spline teeth. One or more of the female spline teeth has a tooth height lesser than a tooth height of another one or more of the female spline teeth. The tooth height of the one or more of the female spline teeth is defined by a top land surface of the one or more of the female spline teeth. The tooth height of the other one or more of the female spline teeth is defined by a top land surface of the other one or more of the female spline teeth. A drainage hole in the top land surface of the one or more of the female spline teeth passes through the one or more of the female spline teeth.