Non-Rotating Hub Cap Assembly With Spacer-Based Bearing Fixing

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Solution Overview

Problem

Existing wheel cover arrangements for motor vehicles are complex and costly, often requiring multiple components like annular bearing seals and dust covers, which complicate assembly and increase costs.

Innovation Solution

A non-rotating wheel cover is attached to a steering knuckle via a spacer that is fixed to a pivot pin, eliminating the need for annular bearing seals and dust covers by using a labyrinthine gap and a labyrinth seal to prevent foreign matter ingress, while securing the wheel cover in a stationary position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a rotating hub cap is used on an axle limb, then the axle limb can be easily assembled and disassembled, but the hub cap cannot be securely detached once fixed due to centrifugal forces

Engineering Contradiction:
Improveease of assembly and disassemblyVSAvoidsecurity of attachment
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent inverts the traditional rotating hub cap design by making the hub cap non-rotating while allowing the axle limb to rotate independently. This is achieved by providing a non-circular opening in the hub cap that matches a non-circular portion of the axle limb, creating a positive mechanical interlock that prevents rotation and secure detachment while maintaining ease of assembly and disassembly.

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

2Reliability

If a non-rotating hub cap with positive engagement is used, then secure attachment is achieved, but the hub cap becomes difficult to detach

Engineering Contradiction:
Improvesecurity of attachmentVSAvoidease of detachment
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent incorporates a spring-loaded plunger that is preliminarily positioned to engage with a detent feature on the axle limb. This preliminary engagement provides secure attachment during operation, while the spring mechanism stores energy that facilitates easy detachment when needed, resolving the contradiction between security and ease of removal.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If a rotating hub cap design is used, then ease of assembly is achieved, but bacterial growth occurs in the gap between hub cap and wheel

Engineering Contradiction:
Improveease of assemblyVSAvoidbacterial growth
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

By inverting the design to use a non-rotating hub cap with a non-circular opening that positively engages with the axle limb, the patent eliminates the rotational movement that creates gaps between the hub cap and wheel. This positive engagement creates a tight fit that prevents gap formation and subsequent bacterial growth, while maintaining ease of assembly through the simple insertion and engagement mechanism.

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

Data Source

PatentEP4422882B1Assembly of a non-rotating hub cap on an axle limb
Publication Date: 2026.04.08 ZF FRIEDRICHSHAFEN AG
  • EP4422882B1 patent drawingFigure 1~2
  • EP4422882B1 patent drawingFigure 2a~3
  • EP4422882B1 patent drawingFigure 4~5

AI summary

The invention relates to an assembly (1) of a non-rotating hub cap on an axle limb for a motor vehicle. The assembly (1) comprises an axle limb, a spacer (4), a wheel hub (5), a wheel bearing (7), a wheel, and a non-rotating hub cap, wherein the axle limb comprises a non-rotating journal (10), and the journal (10) has an outer circumferential surface (11) on which the wheel hub (5) is rotatably mounted by means of the wheel bearing (7). The wheel hub (5) has an outer end face (17) to which the wheel is rotationally fixed, and the spacer (4) is secured to the axle limb (3) such that the spacer (4) does not rotate when the wheel hub (5) is rotating. The spacer (4) is guided through a central wheel hub opening (27) of the wheel hub (5), said central wheel hub opening (27) leading to the wheel bearing (7). The hub cap is directly secured to the spacer (4) in a rotationally fixed manner so that the hub cap does not rotate when the wheel hub (5) is rotating, wherein the hub cap covers at least one part of the exterior of the wheel. The spacer (4) forms a fixing element (39) which extends in an axial direction (x) and which rests against the wheel bearing (7), and the spacer (4) is secured to the journal (10) of the axle limb (3) so that the fixing element (39) of the spacer (4) fixes the wheel bearing (7) in the axial direction (x).