Steering Wheel Rim Cavity Sealing for Vibration Motor Overmolding

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Solution Overview

Problem

Existing steering wheel designs with integrated vibrating motors face efficiency issues due to the motor being located far from the rim, and overmolding processes risk blocking the motor with liquid polymer, leading to quality problems.

Innovation Solution

A steering wheel design with a cavity in the rim containing a motor, a cover to seal the cavity, and sealing means to prevent polymer ingress, ensuring a watertight connection to the vehicle's power supply without additional gaskets, and allowing for controlled device positioning and simplified manufacturing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the motor is integrated into a cavity in the rim, then the vibration efficiency is improved, but liquid polymer can enter the cavity and block the motor during overmolding

Engineering Contradiction:
Improvemotor functionalityVSAvoidpolymer ingress
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The steering wheel is divided into separate functional zones: a sealed cavity for the motor and an overmolded polymer section for the handrest. The cover creates a physical segmentation that prevents polymer from reaching the motor cavity while allowing the handrest to be overmolded separately.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cover acts as an intermediary barrier between the polymer injection process and the motor cavity. It provides a controlled interface that allows structural integration while blocking harmful polymer ingress to the sensitive motor components.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If the cavity is sealed with a cover, then polymer ingress is prevented, but the manufacturing complexity increases

Engineering Contradiction:
Improvepolymer ingress preventionVSAvoidassembly structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The cover performs multiple functions simultaneously: it seals the motor cavity, provides mounting positions for handrests, and creates sealing surfaces for polymer barrier. By merging these functions into a single component, the overall device complexity is reduced despite adding the sealing function.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cover is designed as a multi-functional element that combines structural support, sealing, and device mounting capabilities. This universal component approach reduces the need for separate parts and simplifies the overall manufacturing process.

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

3Ease of manufacture

If the motor is placed far from the rim, then the overmolding process is simpler, but the vibration efficiency decreases

Engineering Contradiction:
Improveovermolding processVSAvoidvibration transmission
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The steering wheel structure is segmented into a sealed motor cavity integrated into the rim and a separate overmolded handrest section. This segmentation allows the motor to be positioned optimally for vibration efficiency while the handrest can be independently overmolded without exposing the motor to polymer.

Inventive Principle:
Principle #1Segmentation

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

The design ensures efficient vibration transmission directly at the rim, reduces manufacturing complexity, and prevents polymer ingress, thereby maintaining motor functionality and improving production efficiency.

Implementation Method 1

sealing means arranged to prevent the polymer from entering the cavity during its injection

Methodology Applied
Scientific EffectPhysical barrier sealing: Physical Containment

Implementation Method 2

a motor driving an unbalanced weight to make the flywheel vibrate

Methodology Applied
Scientific EffectUnbalanced mass vibration: Vibration

Data Source

PatentEP3007956B2Vehicle steering wheel
Publication Date: 2026.03.04 AUTOLIV DEV AB
  • EP3007956B2 patent drawingFigure 1~2

AI summary

The invention relates to a vehicle steering wheel comprising: a rim (10) having a cavity (11); an appliance arranged in the cavity (11) of the rim (10); a cap (40) arranged so as to close the cavity (11); and a polymer injected around the rim (10) and the cap (40); characterised in that the steering wheel comprises sealing means (50) arranged so as to prevent the polymer from entering the cavity (11) during the injection thereof.