Locknut Assembly With Lockwasher Anti-Rotation for Continuous Threads

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Solution Overview

Problem

Existing locknut assemblies are not effective in high vibration/rotational environments and can cause cracking or damage to shaft threads due to their inability to securely engage components without disrupting the continuity of the external threads.

Innovation Solution

A locknut assembly featuring a locknut with internal splines and a lockwasher with a protrusion that engages a corresponding anti-rotation feature on the shaft, allowing for secure engagement without interrupting the external threads, and an optional lockring for securement, ensuring continuous thread integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a traditional locknut assembly with key and keyway is used to prevent rotation, then anti-rotation capability is provided, but the external threads on the shaft are interrupted and can be damaged

Engineering Contradiction:
Improveanti-rotation capabilityVSAvoidthread damage
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The anti-rotation function is extracted from the locknut itself and transferred to a separate lockwasher component. The lockwasher contains the key feature that engages with the keyway in the shaft, while the locknut maintains continuous contact with the shaft threads through its closed design, preventing thread damage while providing anti-rotation capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The locknut assembly is segmented into two distinct components: a locknut for securing and a lockwasher for anti-rotation. This segmentation allows each component to perform its specific function optimally without compromising the shaft threads, as the lockwasher bears the anti-rotation engagement rather than the locknut.

Inventive Principle:
Principle #1Segmentation

2Reliability

If a locknut assembly is used in high vibration environments, then component retention is provided, but the assembly becomes ineffective due to vibration-induced loosening

Engineering Contradiction:
Improvecomponent retentionVSAvoidassembly stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The locknut and lockwasher are merged into a integrated assembly where the lockwasher's key engages the keyway to prevent rotation, while the locknut provides securing force. This combination creates a dual-function assembly that resists both vibration-induced loosening and rotational movement, maintaining reliability in high vibration environments.

Inventive Principle:
Principle #5Merging (Combining)

3Stability of the object's composition

If a locknut with key engagement is used to secure components, then anti-rotation is achieved, but the complexity of the assembly increases

Engineering Contradiction:
Improveanti-rotationVSAvoidassembly complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

Instead of incorporating the anti-rotation key directly into the locknut (which would increase complexity), the design inverts the approach by placing the key feature on the lockwasher that sits outside the locknut. This inversion simplifies the locknut design while maintaining anti-rotation capability through the lockwasher's engagement with the shaft keyway.

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentEP3362695B1Locknut assembly
Publication Date: 2021.03.24 SPS TECHNOLOGIES LLC
  • EP3362695B1 patent drawingFigure 1~6
  • EP3362695B1 patent drawingFigure 7
  • EP3362695B1 patent drawingFigure 8

AI summary

A locknut assembly (20) for securing a component to a shaft is provided that includes, in one form, a locknut (22) defining an internal cavity (32) and an aperture (34) having internal threads (36), the internal cavity (32) defining an internal wall (37) comprising at least one location feature (38). A lockwasher (24) defines an internal cavity (42), an external wall (44) comprising at least one mating location feature (40), and an anti-rotation feature (46) disposed within the internal cavity (42) and adapted for engagement with a corresponding anti-rotation feature (48) located at an end portion (49) of the shaft (30). The internal threads (36) of the locknut aperture (34) engage continuous external threads (31) of the shaft (30), the mating location feature (40) of the lockwasher (24) engages the location feature (38) of the locknut (22), and the anti-rotation feature (46) of the lockwasher (24) engages the corresponding anti-rotation feature (46) of the shaft (30) to limit rotation of the locknut (22).