Wheel Nut Assembly with Integrated Locking Cap

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Solution Overview

Problem

Existing wheel nut retention systems are complex, require multiple components, and lack a simple, cost-effective method to ensure tamper evidence and aesthetic appeal while preventing nut loosening.

Innovation Solution

A wheel nut assembly with a wheel nut and stud featuring internal and external splines and threads, along with a locking cap that securely engages the stud, allowing for easy assembly and tamper-proof operation using a custom allen key.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a compression collar or polygonal extension with separate cap and screw is used, then the nut can be prevented from loosening, but the number of components increases and the assembly becomes complex

Engineering Contradiction:
Improveprevention of nut looseningVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking cap integrates multiple functions into a single component: it has an externally threaded first portion that engages the internal thread of the nut body, and a second cap portion with internal splines that engage the external splines on the stud extension. This merging of functions reduces the number of separate components while maintaining the anti-loosening capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The locking cap is designed to be screwed onto the nut body, with the cap portion fitting over the stud extension. This nested arrangement allows the cap to be assembled onto the existing nut-stud assembly, creating a compact integrated structure that prevents nut loosening without adding excessive complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If multiple separate components (cap, screw, cover) are used to secure the nut, then tamper evidence can be achieved, but the ease of operation during wheel changes deteriorates

Engineering Contradiction:
Improvetamper evidenceVSAvoidease of wheel changes
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The locking cap combines the tamper-evident cover function with the locking mechanism into a single integrated component. The cap can be rotated to engage or disengage from the nut, providing both tamper evidence and a simple operation for wheel changes without requiring separate screws or covers.

Inventive Principle:
Principle #5Merging (Combining)

3Shape

If a custom wheel stud with polygonal extension and separate cap cover is used, then aesthetic appearance can be provided, but the manufacturing cost and complexity increase

Engineering Contradiction:
Improveaesthetic appearanceVSAvoidmanufacturing cost
Core Design Contradiction:
ShapeVSEase of manufacture

Solution Approach 1:

The locking cap serves dual purposes: it provides the aesthetic cover function while simultaneously acting as the locking mechanism through its threaded engagement with the nut and spline engagement with the stud. This eliminates the need for separate aesthetic caps and complex locking mechanisms, reducing manufacturing cost and complexity.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3224490B1Wheel nut assembly
Publication Date: 2020.10.07 FERMAN MICHAEL
  • EP3224490B1 patent drawingFigure 1~2
  • EP3224490B1 patent drawingFigure 3~5
  • EP3224490B1 patent drawingFigure 6~8

AI summary

A wheel nut assembly for fixing a wheel to a vehicle hub which includes a wheel nut with an internal thread and an axial body extension on said nut including a first section with an internal set of axial grooves or ribs and a second section containing a second internal screw thread. There is also a wheel stud having an external thread to co-operate with the internal thread of said wheel nut and having an end portion adapted to project beyond the wheel nut which end portion includes axial grooves or ribs on its external surface. An axial retaining cap consists of an upper externally screw threaded first portion which is adapted to engage the second internal screw thread of said body extension of said nut and attached to said first portion a second cap portion having internal grooves or ribs complementary to the external ribs or grooves on said wheel stud adapted to fit over said wheel stud and having external ribs or grooves adapted to engage the internal set of axial grooves or ribs on the first section of said body extension of said wheel nut. The first portion of said retaining cap is able to be rotated so that it moves axially down the internal screw thread of the second section of said body extension of said wheel nut so that the second portion of said cap is pushed down the end of said wheel stud and is held between the external ribs and grooves of the end of said wheel stud and the internal ribs and grooves of the first section of said body extension of said wheel nut.