Electric heating device and PTC heating element for same

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Solution Overview

Problem

Existing electrical heating devices with PTC heating elements are complex, space-consuming, and inefficient in heat dissipation, particularly in the motor vehicle industry where weight optimization and economical manufacturability are crucial, and there is a need for improved thermal extraction and sealing to handle high system pressures.

Innovation Solution

A PTC heating device with a plug-in connection between the PTC heating element and partition wall, utilizing a flexible elastomer sealing collar for fluid-tight sealing and frictional retention, and a lightweight, cross-linked elastomer housing that allows for efficient heat dissipation and reduced weight, with a design that minimizes the thickness of the sealing collar to accommodate multiple elements closely within the circulation chamber.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If traditional PTC heating elements with overmolded contact sheets and insulating layers are used, then electrical connection is achieved, but the structure becomes space-consuming and complex

Engineering Contradiction:
Improvestructural complexityVSAvoidspace consumption
Core Design Contradiction:
Device complexityVSVolume of moving object

Solution Approach 1:

The contact sheet and insulating layer are extracted from the overmolding process and implemented as separate components. The contact sheet is inserted into a recess in the heating element housing, and the insulating layer is placed over the contact sheet, eliminating the need for complex overmolding while achieving the same electrical connection and insulation functions

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The heating element housing is divided into segments with recesses that accommodate the contact sheet and insulating layer separately. This segmentation allows for simpler manufacturing and assembly while reducing overall structural complexity and space requirements compared to a monolithic overmolded design

Inventive Principle:
Principle #1Segmentation

2Loss of energy

If sufficient heat dissipation is not achieved, then PTC elements can be operated with poor efficiency, but improving heat dissipation increases device complexity

Engineering Contradiction:
Improveheat dissipation efficiencyVSAvoidthermal management complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The heating element housing is designed with localized thermal management features, including recesses that facilitate heat extraction from specific areas of the PTC element. The partition wall includes openings that allow heat to be conducted from the PTC element to the housing, providing targeted heat dissipation without requiring complex thermal management systems

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The housing material acts as an intermediary for heat transfer from the PTC element to the surrounding environment. The partition wall serves as a thermal conduit, conducting heat from the PTC element through the housing structure, enabling efficient heat dissipation through the housing itself rather than requiring separate cooling mechanisms

Inventive Principle:
Principle #24Intermediary (Mediator)

3Weight of stationary object

If a lightweight housing material is used, then weight is reduced, but sealing capability under high pressure may be compromised

Engineering Contradiction:
Improvehousing weightVSAvoidsealing capability
Core Design Contradiction:
Weight of stationary objectVSReliability

Solution Approach 1:

The heating element housing is made from a composite material consisting of a thermoplastic matrix reinforced with glass fibers. This composite provides both the lightweight property of thermoplastics and the enhanced mechanical strength and sealing capability provided by the glass fiber reinforcement, allowing the housing to withstand high system pressures while maintaining reduced weight

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The material properties of the housing are optimized by adjusting the glass fiber content and distribution within the thermoplastic matrix. This parameter change enables the housing to achieve the necessary pressure resistance for sealing while maintaining the weight advantages of lightweight materials, balancing both requirements simultaneously

Inventive Principle:
Principle #35Parameter changes

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 provides a cost-effective, lightweight, and efficient heat dissipation system that maintains fluid-tight sealing under high pressures, enabling reliable operation in motor vehicles with reduced material usage and improved thermal management.

Implementation Method 1

PTC heating elements arranged in a circulation chamber (14)... PTC elements (120)... contact plates (128) that energize the PTC element

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

flexible elastomer sealing collar (48) for fluid-tight sealing and frictional retention

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 3

flexible elastomer sealing collar (48) for fluid-tight sealing... cross-linked elastomer housing

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 4

efficient heat dissipation... improved thermal management... partition wall (54), which separates the circulation chamber from a connection chamber

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3334244B1Electric heating device and PTC heating element for same
Publication Date: 2019.12.11 EBERSPACHER CATEM GMBH & CO KG
  • EP3334244B1 patent drawingFigure 1
  • EP3334244B1 patent drawingFigure 2
  • EP3334244B1 patent drawingFigure 3

AI summary

The present invention relates to an electrical heating device with a plurality of PTC heating elements (40) arranged in a circulation chamber (62) with a heating element housing (134), which has at least one PTC element (120) and contact tongues (42) that energize the PTC element contact plates (128) forming an electrical plug connection as a structural unit, and with a partition (54) which separates the circulation chamber (62) from a connection chamber (56) in which the contact tongues (42) of the PTC projecting through the partition (54). -Heating element (40) are exposed and electrically connected and a PTC element and a housing of such an electrical heating device. For economical production, the invention proposes a plug-in connection formed between the partition (54) and the PTC heating element (40), via which the PTC heating element (40) is frictionally and/or positively held on the partition (54) in the plugging direction .