Steering Wheel Planar Heater with Sparse Outer Winding

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Solution Overview

Problem

Conventional planar heat generating elements for steering wheels result in uneven temperature distribution and sensation when heated, leading to discomfort and difficulty in gripping due to differences in heat conduction and dissipation across the wheel's surface.

Innovation Solution

The linear heaters are disposed along the circumferential direction of the ring portion with a sparse density at the outermost circumferential portion, allowing for adjustable heat generation to match the user's grip and enhancing the sensation of warmth, while also increasing curvature to improve the touching feeling and external appearance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the heating portion of the planar heat generating element is made uniform, then the manufacturing is simplified, but the temperature distribution does not match user sensation and causes uneven heating at different steering wheel positions

Engineering Contradiction:
Improveheating portion uniformityVSAvoidtemperature distribution uniformity
Core Design Contradiction:
Ease of manufactureVSTemperature

Solution Approach 1:

The patent applies local quality by varying the heating wire density across different regions of the planar heat generating element. Specifically, the heating wire density is made lower at the outermost circumferential portion where palms contact, and higher at inner portions where fingertips contact. This non-uniform local distribution compensates for differences in heat conduction and user sensation at different steering wheel positions, resolving the contradiction between manufacturing simplicity and temperature distribution uniformity.

Inventive Principle:
Principle #3Local quality

2Temperature

If the heating wire density is increased at the outermost circumferential portion, then the palms receive sufficient warmth, but the temperature becomes too high causing discomfort and gripping difficulty

Engineering Contradiction:
Improvepalms warmthVSAvoidgripping comfort
Core Design Contradiction:
TemperatureVSEase of operation

Solution Approach 1:

The patent reduces heating wire density at the outermost circumferential portion compared to conventional uniform designs. This local reduction prevents excessive heat generation at palm contact areas, maintaining warmth while avoiding discomfort and gripping difficulty. The principle of local quality allows different heating intensities in different regions to match user sensation and operational comfort requirements.

Inventive Principle:
Principle #3Local quality

3Power

If the linear heaters are disposed with high density throughout, then sufficient heat is generated, but the heaters stand out from the covering material surface degrading external appearance and touching feeling

Engineering Contradiction:
Improveheat generationVSAvoidsurface smoothness
Core Design Contradiction:
PowerVSShape

Solution Approach 1:

The patent applies local quality by concentrating heating wire density in specific regions rather than uniformly distributing it. The heating wires are arranged with lower density at the outermost circumferential portion and higher density toward the center. This local concentration achieves sufficient heat generation while reducing the overall prominence of heaters on the surface, thereby maintaining better external appearance and touching feeling.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent transforms the heater arrangement from a two-dimensional uniform grid to a three-dimensional curved path following the circumferential direction. By disposing linear heaters along curved paths with varying density, the solution achieves effective heat generation while the heaters remain less prominent on the surface, addressing both power output and surface smoothness requirements.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

This configuration ensures a more uniform and comfortable warmth sensation for the user by adjusting heat generation to match the grip pattern and preventing external appearance issues like wrinkles and uneven temperature distribution.

Implementation Method 1

a heating heater which generates heat by being connected to a power supply

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

since heat conduction or heat dissipation is not even and hence the heating state is not even depending on positions on the steering wheel

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2003934B1Planar heating element for steering wheel
Publication Date: 2014.08.20 PANASONIC HOLDINGS CORP
  • EP2003934B1 patent drawingFigure 1
  • EP2003934B1 patent drawingFigure 2
  • EP2003934B1 patent drawingFigure 3

AI summary

The invention relates to a planar heat generating element for use on steering wheels of automotive vehicles and motorboats, and a problem of the invention is to adjust a temperature portion of a planar heat generating element which is attached to a steering wheel, so as to enhance the sensation of using the steering wheel by the user when he or she grips thereon. In the invention, since linear heaters (17) of a planar heat generating element (14) are provided so as to be turned repeatedly along a circumferential direction and such that the density of turns of the liner heaters (17) at an outermost circumferential portion of a ring portion (12) becomes sparse, the temperature of the outermost circumferential portion of the ring portion (12) with which the palms of the user are brought into contact when he or she grips the ring portion (12) can be made to be adjusted, and the heat generation of the planar heat generating element (14) can be adjusted so as to match the user's way of gripping, thereby the sensation of using the steering wheel felt by the user when he or she grips thereon being able to be enhanced.