Steering Wheel Airbag Mount With Adjustable Spacers for Gap Alignment

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Solution Overview

Problem

Current vehicle assembly methods face challenges in achieving precise and cost-effective alignment of components, such as airbag modules, relative to carriers like steering wheels, due to manufacturing tolerances, which require additional manufacturing efforts and costs.

Innovation Solution

A bearing unit with adjustable spacer elements and threaded fastening mechanisms allows for precise positional alignment of components, enabling adjustment in three translational and three rotational degrees of freedom, using threads and detent springs for easy assembly and re-adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If manufacturing tolerances of components are reduced to achieve uniform and narrow gaps, then gap uniformity is improved, but manufacturing effort and costs increase significantly

Engineering Contradiction:
Improvegap uniformityVSAvoidmanufacturing effort
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent introduces an intermediate component (adjustable spacer element) between the support and the component to be fastened. This spacer element compensates for manufacturing tolerances and enables uniform gaps without requiring high-precision manufacturing of the main components. The spacer acts as a mediator that absorbs dimensional variations.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The spacer element features an adjustable length parameter that can be modified to compensate for manufacturing tolerances. By changing the length parameter of the spacer, uniform gaps can be achieved without requiring high-precision manufacturing of the support or component, thus reducing manufacturing effort and costs.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If intermediate components such as spacers are used to compensate for manufacturing tolerances, then gap uniformity is improved, but device complexity and costs increase due to additional elements

Engineering Contradiction:
Improvegap uniformityVSAvoidnumber of components
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The spacer element is designed with adjustable length through threaded connections, allowing it to adapt to different manufacturing tolerances. This dynamic adjustability enables a single spacer design to compensate for various dimensional variations, reducing the need for multiple different spacer types or additional components.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The adjustable spacer element serves multiple functions: it compensates for manufacturing tolerances, enables gap adjustment, and provides a mounting interface for the component. This multi-functionality reduces the need for additional specialized components, thereby limiting the increase in device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Manufacturing precision

If post-processing steps are used to adjust support surfaces to current tolerances, then gap uniformity is improved, but manufacturing effort increases and requires precise determination of component dimensions

Engineering Contradiction:
Improvegap uniformityVSAvoidmanufacturing effort
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The adjustable spacer element allows for preliminary positioning and alignment before final fastening. The component can be positioned on the spacer, and the spacer length can be adjusted to achieve the desired gap uniformity before the component is permanently fixed, simplifying the overall manufacturing process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The spacer element serves as an intermediary that absorbs the need for post-processing adjustments. By adjusting the spacer length, the desired gap uniformity is achieved without requiring post-processing steps on the support or component surfaces, thereby reducing manufacturing effort.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Ease of operation

If eccentrics are used for adjustment purposes, then limited positional adjustment is achieved, but adjustment range is very limited in a predetermined direction and cannot fully compensate for statistically distributed tolerances

Engineering Contradiction:
Improvepositional adjustmentVSAvoidadjustment range
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The spacer element features an adjustable length parameter that can be modified continuously, providing a broader adjustment range compared to eccentrics. This allows compensation for statistically distributed tolerances in multiple directions, not just in a predetermined direction as with eccentrics.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The adjustable spacer enables dynamic adaptation to different tolerance distributions through length adjustment. Unlike fixed eccentrics that only provide adjustment in a predetermined direction, the adjustable spacer can be modified to compensate for tolerances in various directions, enhancing adaptability.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3580098B1Bearing unit, steering-wheel subassembly and method for producing a vehicle subassembly
Publication Date: 2024.03.13 ZF AUTOMOTIVE SAFETY GERMANY GMBH
  • EP3580098B1 patent drawingFigure 1~2
  • EP3580098B1 patent drawingFigure 3~4
  • EP3580098B1 patent drawingFigure 5~6

AI summary

A description is given of a bearing unit of a vehicle subassembly, wherein the vehicle subassembly has a vehicle-mounted support, in particular a vehicle-steering wheel (10), and a component which is to be fastened on the support, in particular an airbag module. The bearing unit comprises at least one adjustable spacer element (14a, 14b, 14c) for orienting the position of the component on the support. Also provided are a bearing unit having a plurality of spacer elements (14a), which can be adjusted independently of one another, and a steering-wheel subassembly having a vehicle-steering wheel (10) and an airbag module, wherein the vehicle-steering wheel (10) and the airbag module are connected to one another by the bearing unit. The invention additionally relates to a method for producing a vehicle subassembly having a vehicle-mounted support, having a component which is to be fastened on the support, and having at least one bearing unit.