Locking Nut With Unidirectional Securing Element for Shaft Retention
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Solution Overview
Problem
Existing locking mechanisms for securing shaft attachments, such as caulking nuts and castle nuts, are complex, labor-intensive, prone to material weakening, and difficult to adjust, leading to potential damage and safety risks due to overtightening or loosening under alternating loads.
Innovation Solution
A locking nut with a unidirectionally rotatable securing element that engages with a recess in the shaft, allowing easy assembly and self-locking in the unscrewing direction, featuring elastically deformable locking teeth that prevent accidental loosening without special tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If plastic deformation is used to secure the caulking nut or locking element in the recess, then form-fitting and rotational fixation is achieved, but the process becomes complex and labor-intensive requiring special tools
Solution Approach 1:
The locking element is divided into separate functional components: a securing element (such as a retaining ring or clamping ring) that engages with the shaft recess, and a locking nut that secures the attachment element. This segmentation allows each component to perform its specific function independently, simplifying the overall fastening process while maintaining reliable fixation.
Solution Approach 2:
The securing element is pre-configured with engagement features (such as hooks, lugs, or deformable sections) that are designed to engage with the shaft recess in advance. This preliminary preparation eliminates the need for complex deformation processes during assembly, as the engagement structure is already optimized for automatic engagement when the locking nut is tightened.
2Reliability
If plastic deformation is used to secure the locking element, then form-fitting fixation is achieved, but material weakening occurs leading to corrosion problems
Solution Approach 1:
By separating the fixation function into a dedicated securing element that engages with the shaft recess, the main locking nut and attachment element retain their full material strength. The securing element is designed specifically for engagement without requiring plastic deformation of critical load-bearing components, thus preventing material weakening and corrosion issues.
Solution Approach 2:
The securing element acts as an intermediary component between the locking nut and the shaft recess. It provides the form-fitting engagement with the recess while the locking nut provides the clamping force, thereby eliminating the need for plastic deformation of the locking nut itself and preserving its material strength and corrosion resistance.
3Reliability
If a cotter pin or locking bolt is used to secure the castle nut, then form-fitting fixation is achieved, but installation becomes time-consuming and labor-intensive
Solution Approach 1:
The securing element is integrated with the locking nut as a combined assembly. The securing element is positioned within or on the locking nut such that both components are installed simultaneously in a single operation, eliminating the separate step of installing a cotter pin or locking bolt and significantly reducing installation time while maintaining reliable fixation.
Solution Approach 2:
The securing element is pre-positioned on or within the locking nut before installation. This preliminary arrangement ensures that when the locking nut is tightened onto the shaft, the securing element automatically engages with the shaft recess in the same motion, eliminating the need for separate installation steps and reducing overall installation time.
4Reliability
If the locking element secures the locking nut in both screwing and loosening directions, then rotational fixation is achieved, but the locking nut cannot be readjusted leading to increased axial play
Solution Approach 1:
The engagement features of the securing element are designed with asymmetric geometry that provides form-fitting fixation in the loosening direction while allowing controlled movement or adjustment in the screwing direction. This asymmetric design enables the locking nut to be securely locked against loosening while still permitting readjustment during installation or maintenance, thereby maintaining both rotational fixation and adaptability.
Solution Approach 2:
The securing element incorporates dynamic characteristics that allow it to adapt to different operational conditions. For example, the engagement features may include elastic or deformable sections that provide flexible engagement, enabling the locking mechanism to maintain secure fixation while accommodating adjustments and reducing axial play under varying loads.
5Reliability
If deformable tooth flanks are used in the retaining ring, then non-rotating locking is achieved, but manufacturing precision requirements increase and strength is reduced
Solution Approach 1:
The locking mechanism is segmented into the locking nut with external toothing and a separate securing element with internal toothing. The engagement between these two components provides the anti-rotation capability through their mutual toothing engagement, eliminating the need for deformable tooth flanks in a single-ring design and reducing manufacturing precision requirements while maintaining reliability.
Solution Approach 2:
The securing element with internal toothing acts as an intermediary that engages with the external toothing of the locking nut. This intermediate toothing interface provides the necessary anti-rotation capability through precise gear-like engagement, avoiding the need for deformable flanks and reducing manufacturing complexity and precision requirements compared to monolithic designs.
6Reliability
If deformable tooth flanks are used in the retaining ring, then non-rotating locking is achieved, but individual tooth flanks may break off under cyclical loading
Solution Approach 1:
The locking mechanism uses separate locking nut and securing element components with external and internal toothing respectively. This segmentation distributes the mechanical loads across multiple engagement points and prevents stress concentration in individual tooth flanks, eliminating the risk of tooth breakage under cyclical loading while maintaining effective anti-rotation capability.
Solution Approach 2:
The securing element with internal toothing serves as an intermediary that distributes and balances the loads between the locking nut and the shaft. This intermediate toothing structure prevents excessive stress on individual tooth flanks by spreading the contact forces across the entire toothing interface, thereby preventing tooth breakage under cyclical operational loads.
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
Ensures secure attachment without additional steps or tools, allowing manual assembly and disassembly with controlled torque, preventing unintentional loosening and damage, while maintaining operational reliability.
Implementation Method 1
the securing element is designed as a circumferentially open locking ring which is elastically deformable on one side along the screwing direction of rotation in such a way that the locking nut can be rotated, in particular slidingly, along the screwing direction of rotation relative to the securing element
Implementation Method 2
the engagement section, in the assembled state, engages in a recess (24) in the shaft (14) and holds the locking nut (10) along a loosening direction of rotation (D2), in particular in a form-fitting manner
Data Source
Figure 1a~1b
Figure 2a~3
Figure 4a~4d
AI summary
The invention relates to a locking nut (10) comprising a securing element (18) as an axial securing means for an attachment element (12) of a shaft (14), in particular a support of a gear shaft or a wheel bearing of a universal shaft, wherein the locking nut (10) can be screwed in a screwing direction (D1) onto a threaded shaft section (16), in particular at the end, of the shaft (14) in order to clamp the attachment element (12) axially and along a screw axis (S) on the shaft (14) when in the mounted state, wherein the securing element (18) has an engagement section (22) which engages in a cut-out (24) in the shaft (14) and holds the locking nut (10) in an unscrewing direction (D2) when in the mounted state. The locking nut (10) supports the securing element (18) along the screw axis (S), wherein the locking nut (10) can be rotated on one side in the screwing direction (D1) relative to the securing element (18).