Retaining Ring Lug Anchoring Against Centrifugal Expansion

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Solution Overview

Problem

Retaining rings on spinning shafts subjected to centrifugal force can expand radially and dislocate from the retaining groove, especially when operating speeds exceed the manufacturer-recommended limits.

Innovation Solution

A retaining ring system with radially extending lug portions and a retention lip configuration that allows the retaining ring to be securely snap-fit into a groove on a rotatable shaft, with the lugs positioned to prevent centrifugal force from dislodging the ring by rotating them into an installed position where the retention lip circumscribes the lugs, preventing expansion of the central opening.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the shaft operates at high speeds beyond manufacturer-recommended limits, then productivity increases, but the retaining ring expands radially and dislocates from the groove due to centrifugal force

Engineering Contradiction:
Improveshaft operating speedVSAvoidretaining ring retention
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The retaining ring is segmented into a body portion and lug portions. The lug portions are selectively positioned within the groove at different angular locations to provide distributed anchoring points that resist centrifugal expansion forces more effectively than a continuous ring structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The retaining ring is pre-formed with lugs that can be positioned in different angular locations within the groove before operation. This preliminary configuration allows the lugs to be optimally positioned to counteract centrifugal forces before the shaft begins rotating at high speeds.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the retaining ring is made more robust to prevent dislocation, then reliability improves, but the device complexity increases

Engineering Contradiction:
Improveretaining ring retentionVSAvoidretaining ring structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Instead of making the entire retaining ring more robust, only the lug portions are designed as separate elements that can be selectively positioned. This segmentation provides enhanced retention reliability through distributed anchoring while maintaining simplicity in the overall ring body structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The lug portions are designed with specific local properties (ability to be positioned at different angular locations) while the main body of the retaining ring maintains its simple continuous structure. This local differentiation provides enhanced retention only where needed without complicating the overall design.

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 system effectively secures the retaining ring on the shaft, preventing dislocation due to centrifugal force, ensuring reliable retention even at high speeds beyond manufacturer-recommended limits.

Implementation Method 1

The retaining ring is expanded and snap fit within a groove formed in the end of the shaft

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

In situations where retaining rings are located on a spinning shaft and subjected to centrifugal force, sufficient centrifugal force can cause the retaining ring to expand radially and dislocate from the retaining groove

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP2932107B1Retaining ring retention system and method
Publication Date: 2019.03.06 MACK TRUCKS INC
  • EP2932107B1 patent drawingFigure 1
  • EP2932107B1 patent drawingFigure 2
  • EP2932107B1 patent drawingFigure 3

AI summary

The present invention relates to a retained member configured to prevent centrifugal force from disassociating a retaining ring provided with lugs from a groove located on a rotatable shaft when securing the retained member to the rotatable shaft and rotating with the shaft. The retained member includes a substantially annular portion and a retention lip provided with a cutout portion. The substantially annular portion defines an opening sized to receive the rotatable shaft so that the retained member is rotatable with the shaft. The cutout portion is configured to accommodate the lugs when in an installing position as the retained member is snap fit into the groove.