Spline Locking Coupling With Compact Axial Retention

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Solution Overview

Problem

Existing mechanical couplings between shafts and hubs using splined interfaces often require additional components like retaining rings to prevent axial movement, increasing the overall length and complexity of the coupling, and requiring specialized tools for assembly and disassembly.

Innovation Solution

A coupling system comprising a shaft, a hub, a retainer, and a fastener, where the hub and retainer splines are meshed with the shaft splines, and the fastener connects the retainer to the hub, allowing for a compact, strong, and easily assembled configuration with reduced axial length, and enabling blind rotation for simplified assembly in confined spaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a retaining ring is used to prevent axial movement of the hub, then axial stability is improved, but the overall axial length and device complexity increase

Engineering Contradiction:

Improveaxial stabilityVSAvoidcoupling complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The retainer combines multiple functions into a single component: it prevents axial movement of the hub (like a retaining ring), provides rotational locking through splines, and eliminates the need for separate retaining rings and grooves. This merging reduces device complexity while maintaining axial stability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The retainer serves multiple purposes simultaneously: it acts as an axial stop for the hub, provides rotational locking through spline engagement, and serves as a mounting structure for fasteners. This multi-functionality reduces the number of separate components needed, thereby reducing device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Stability of the object's composition

If a retaining ring groove is added to the shaft, then axial retention is improved, but the axial length of the shaft increases

Engineering Contradiction:

Improveaxial retentionVSAvoidshaft axial length

Core Design Contradiction:

Stability of the object's compositionVSLength of moving object

Solution Approach 1:

The retainer combines the axial retention function (previously requiring a groove) with the rotational locking function in a single component that mounts on the shaft without requiring additional axial space for grooves.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

Instead of extending the shaft axially to create a groove for retaining ring placement, the solution moves the retention mechanism to a different dimensional approach by using a retainer that wraps around the shaft and hub assembly, providing retention without axial extension.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Manufacturing precision

If specialized tools are used for assembly, then assembly precision is improved, but ease of operation deteriorates

Engineering Contradiction:

Improveassembly precisionVSAvoidassembly ease

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The retainer and hub assembly is designed to be self-aligning through spline engagement, allowing workers to assemble the coupling using standard tools and basic hand operations without requiring specialized assembly equipment or tools.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The assembly process allows for dynamic adjustment and self-alignment of the hub and retainer on the shaft through the spline interface, enabling easy installation without rigid precision alignment requirements that would necessitate specialized tools.

Inventive Principle:

Principle #15Dynamics

4Stability of the object's composition

If the shaft is extended axially to accommodate a retaining ring groove, then axial retention is improved, but the volume of the shaft increases

Engineering Contradiction:

Improveaxial retentionVSAvoidshaft volume

Core Design Contradiction:

Stability of the object's compositionVSVolume of moving object

Solution Approach 1:

The solution transitions from axial extension of the shaft to a radial/circumferential retention mechanism using the retainer that wraps around the assembly, maintaining retention functionality without increasing shaft volume.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS11655855B2Locking coupling for rotating assembly

Publication Date: 2023.05.23 RAYTHEON CO

AI summary

A coupling is provided that includes a shaft, a hub, a retainer and a fastener. The shaft includes a plurality of shaft splines. The shaft splines are arranged circumferentially about an exterior of the shaft. The hub includes a plurality of hub splines, a hub bore and a hub fastener aperture. The hub splines are arranged circumferentially about the hub bore. The hub splines are mated with the shaft splines. The shaft is within the hub bore. The retainer includes a plurality of retainer splines, a retainer bore and a retainer fastener aperture. The retainer splines are arranged circumferentially about the retainer bore. A first of the retainer splines circumferentially overlaps and is axially next to a first of the shaft splines. The shaft is within the retainer bore. The fastener is within the hub fastener aperture and the retainer fastener aperture. The fastener connects the retainer to the hub.