Quill Shaft Oil Ejection for Spline Lubrication at High Speed

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Solution Overview

Problem

Conventional power transmission devices face issues with large misalignments at high speeds and warm temperatures, leading to imbalance loads and increased maintenance due to inefficient oil lubrication mechanisms, which require additional parts and frequent servicing.

Innovation Solution

A power transmission device with a quill shaft featuring an obliquely angled ejector orifice and raised bosses that control oil flowrate and volume, ensuring effective lubrication and cooling of splines and teeth, allowing for single-end oil capture and feed, reducing the need for additional components and frequent maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional grease-packed splines or separate oil injectors are used, then lubrication is provided, but device complexity and mass increase

Engineering Contradiction:
Improvelubrication effectivenessVSAvoidnumber of parts and accessories
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent integrates the oil delivery mechanism directly into the quill shaft by forming ejector orifices and raised bosses as integral features of the shaft itself, rather than using separate injectors or grease packs. This merging of functions reduces the number of discrete parts while maintaining effective lubrication of the spline teeth.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The quill shaft serves multiple functions: it transmits torque through spline engagement and simultaneously delivers lubrication through its integrated ejector orifices and raised bosses. This multi-functionality eliminates the need for dedicated lubrication components, reducing overall device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If additional parts and accessories are added for oil delivery, then lubrication is improved, but maintenance frequency and cost increase

Engineering Contradiction:
Improvelubrication controlVSAvoidservicing frequency
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

By combining the lubrication delivery function into the quill shaft structure itself through integrated ejector orifices and raised bosses, the patent reduces the number of serviceable components. Fewer discrete parts mean fewer potential failure points and reduced maintenance frequency.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The quill shaft's integrated design allows it to self-deliver lubrication through its own structure without requiring external injectors or grease packs that would need separate servicing. The system serves itself by incorporating the lubrication delivery mechanism within the rotating shaft.

Inventive Principle:
Principle #25Self-service

3Productivity

If traditional oil injection methods are used, then minimal lubrication is provided, but the system operates at high speeds with low mass

Engineering Contradiction:
Improveoperational speedVSAvoidlubrication sufficiency
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The ejector orifices are positioned on the raised bosses that rotate with the quill shaft, creating a dynamic lubrication delivery system. The rotation of the shaft naturally directs oil through the ejector orifices onto the spline teeth, providing effective lubrication at high speeds without requiring complex external injection systems.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The raised bosses with ejector orifices are strategically positioned to deliver oil precisely where needed on the spline teeth. This localized delivery ensures sufficient lubrication at high speeds by targeting the specific contact areas between mating splines, maintaining reliability without adding system mass.

Inventive Principle:
Principle #3Local quality

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

The solution provides reliable lubrication and cooling, extending the life of mechanically engaged components, reducing misalignment issues and maintenance frequency while operating efficiently at high speeds with reduced mass and handling large misalignments.

Implementation Method 1

A raised boss on an interior surface of the quill shaft has an aperture therein such that the raised boss is adapted to eject a fluid through the aperture to outside of the quill shaft

Methodology Applied
Scientific EffectFluid pressure: Pressure Gradient

Implementation Method 2

oil has been introduced into the power transmission device to lubricate the teeth on the quill shaft splines that are in engagement on both ends of the quill shaft

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP3456941B1Power transmission device
Publication Date: 2021.02.03 ROLLS ROYCE CORP
  • EP3456941B1 patent drawingFigure 1
  • EP3456941B1 patent drawingFigure 2
  • EP3456941B1 patent drawingFigure 3

AI summary

A power transmission device, comprising a quill shaft having a first end and a second end; a first shaft engaged with the first end of the quill shaft; a second shaft engaged with the second end of the quill shaft; and a raised boss on an interior surface of the quill shaft having an aperture therein, wherein the raised boss is adapted to eject a fluid through the aperture to outside of the quill shaft.