Deformable Heating Element for Steering Wheel
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Solution Overview
Problem
Existing steering wheel heating elements face challenges in adapting to the cross-sectional shape of the steering wheel rim and are often damaged during production due to high thermal stress, with the heating conductor sometimes visible on the cover.
Innovation Solution
A deformable heating element with a dual-layer base material, where the front layer has lower compressive strength and bulk density than the back layer, allowing the heating conductor to be embedded and hidden from view, and using materials like needle felt or semi-wool wadding to ensure the conductor is not thermally stressed during manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If the heating element is embedded in thermoplastic material through fusion process, then the heating conductor is hidden from view and not felt, but the heating element is subjected to very high thermal stress during manufacturing
Solution Approach 1:
The base material is divided into two distinct layers: a front layer with lower compressive strength and bulk density for embedding the heating conductor, and a back layer with higher compressive strength and bulk density for structural support and adhesive bonding. This segmentation allows the heating conductor to be hidden in the softer front layer without exposing it to high thermal stress from the fusion process, as the bonding layer is applied separately to the back layer.
Solution Approach 2:
Different regions of the base material are given different properties: the front layer has lower compressive strength and bulk density to facilitate embedding and hiding of the heating conductor, while the back layer has higher compressive strength and bulk density to provide structural support and ensure reliable adhesive bonding to the steering wheel body. This local differentiation resolves the contradiction by allowing the heating conductor to be hidden without requiring high-temperature fusion that would damage it.
2Ease of manufacture
If the heating element is made with uniform base material, then the manufacturing process is simpler, but the heating conductor may be visible on the cover
Solution Approach 1:
The base material is differentiated into two layers with different properties: the front layer has lower compressive strength and bulk density to allow the heating conductor to be embedded and hidden, while the back layer has higher compressive strength for structural support. This local quality differentiation ensures the heating conductor is not visible through the cover while maintaining a manageable manufacturing process through separate layer application.
Solution Approach 2:
The base material is constructed as a composite of two layers with different physical properties. The front layer (lower density) and back layer (higher density) are bonded together to form a composite structure that combines the benefits of both materials: one layer hides the heating conductor while the other provides structural integrity and bonding capability.
3Strength
If the front layer has high compressive strength, then the structural support is better, but the heating conductor cannot be properly embedded and hidden
Solution Approach 1:
The base material is segmented into two layers with different compressive strengths. The front layer has lower compressive strength to allow the heating conductor to be embedded and hidden effectively, while the back layer has higher compressive strength to provide the necessary structural support. This segmentation resolves the contradiction by distributing the functional requirements to different layers.
Solution Approach 2:
Different compressive strength properties are assigned to different regions of the base material. The front layer has lower compressive strength optimized for embedding and hiding the heating conductor, while the back layer has higher compressive strength optimized for structural support. This local quality differentiation allows both requirements to be satisfied simultaneously.
4Productivity
If rapid heating to very high temperatures is applied during manufacturing, then the adhesive activation and manufacturing cycle time are improved, but the heating element is subjected to very high stress
Solution Approach 1:
The manufacturing process is segmented into separate steps: the heating conductor is first embedded in the front layer without high-temperature exposure, then the adhesive bonding layer is applied separately to the back layer. This segmentation allows the adhesive activation to occur without subjecting the heating conductor to high thermal stress, resolving the contradiction between fast manufacturing and element protection.
Solution Approach 2:
The base material structure acts as an intermediary that protects the heating conductor from thermal stress during adhesive activation. The two-layer construction with the heating conductor embedded in the front layer serves as a buffer, allowing the back layer to be bonded using rapid heating processes without transmitting excessive thermal stress to the heating conductor.
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 solution allows for a cost-effective, thermally stress-free production of heating elements that can be easily attached to curved surfaces like steering wheel rims without the heating conductor being visible, ensuring durability and adaptability.
Implementation Method 1
at least one heating conductor (10) which is laid and fastened on one side, referred to as a front layer, of the base material
Data Source
Figure 1~4
AI summary
The element (6) has a heating conductor (10) displaced and attached on a flat base material (7). One side of the base material is formed as a front-side layer (8). The front-side layer has a lower strain hardness and/or volume density than that in a region of an opposite rear-side-layer (9) in the base material. The base material has specific gravity, which ranges from 50 to 100 kilogram/meter cube. The rear-side layer of the base material is formed from knitted fabric. The base material is formed from a needle fleece on the front-side layer.