PTC Heating Block Grid Structure for Tolerance-Tolerant Assembly

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Solution Overview

Problem

The existing electrical heating devices face challenges in simplifying the production process and reducing costs while ensuring accurate positioning and prestressing of heat-generating elements within the housing, particularly due to the complexity of assembly and the need for precise geometric tolerances between housing parts and heating block layers.

Innovation Solution

The electrical heating device incorporates a grid arrangement where struts extending at right angles to the layers are part of the housing, and additional struts formed by the heating block itself provide shielding and stiffening, allowing for a form-fitting connection that compensates for manufacturing tolerances and thermal expansion, enabling easier assembly and use of standardized components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the housing parts are designed with precise geometric tolerances to ensure accurate positioning of heating block layers, then the positioning accuracy is improved, but the manufacturing cost and complexity increase

Engineering Contradiction:
Improvepositioning accuracy of heating block layersVSAvoidgeometric tolerance requirements
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent introduces a grid arrangement consisting of struts as an intermediary element between the housing parts and the heating block layers. These struts provide a standardized mounting structure that simplifies positioning and reduces the need for complex geometric tolerances in the housing parts themselves, thereby resolving the contradiction between positioning accuracy and manufacturing complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The housing structure is segmented into modular components including the grid arrangement with struts, housing parts, and heating block layers. This segmentation allows each component to be manufactured with standard tolerances and assembled together, reducing the need for high-precision machining of individual parts while maintaining overall positioning accuracy

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If the assembly process requires precise positioning of each heating block layer, then the positioning accuracy is improved, but the assembly time and labor costs increase

Engineering Contradiction:
Improvepositioning accuracy during assemblyVSAvoidassembly time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The grid arrangement with struts is pre-assembled within the housing parts before the heating block layers are installed. This preliminary action creates ready-made positioning references and mounting points, allowing the heating block layers to be quickly and accurately positioned during final assembly without requiring time-consuming alignment procedures

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The struts serve as intermediary elements that facilitate quick and accurate assembly by providing standardized mounting points and positioning references. This intermediary structure eliminates the need for complex alignment procedures during assembly, thereby reducing assembly time while maintaining positioning accuracy

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If standardized components are used for housing parts, then the manufacturing cost is reduced, but the ability to accommodate specific heating block positioning requirements deteriorates

Engineering Contradiction:
Improvemanufacturing costVSAvoidadaptability to positioning requirements
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The positioning function is segmented from the housing parts and implemented through the modular grid arrangement with struts. This allows the housing parts to be manufactured as standardized components using cost-effective methods, while the grid arrangement provides the necessary adaptability and positioning precision through its modular structure that can be configured to accommodate different heating block layer arrangements

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The grid arrangement with struts serves multiple functions: it provides structural support, establishes positioning references, and enables adaptable mounting of heating block layers. This multi-functional design allows standardized housing parts to accommodate various positioning requirements without requiring custom-manufactured components, thereby maintaining both cost-effectiveness and adaptability

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

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 design simplifies the assembly process, reduces production costs, and ensures reliable positioning of heat-generating elements, allowing for the use of standardized components and improved mechanical interaction, while maintaining effective heat transfer and electrical conductivity.

Implementation Method 1

The heat-generating elements of the heating block usually include several PTC heating elements which are provided one above the other in one plane and are arranged between conductor tracks

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

The heat generated by the heat-generating elements is transferred to the medium to be heated, i.e. the air, via heat-emitting elements

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

This flows through the housing through the two frame openings

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP2017103B1Electric heating device
Publication Date: 2016.05.04 EBERSPACHER CATEM GMBH & CO KG
  • EP2017103B1 patent drawingFigure 1~2
  • EP2017103B1 patent drawingFigure 3
  • EP2017103B1 patent drawingFigure 4~5

AI summary

The present invention relates to an electric heating device with a heating block (8) which is held in a housing (2) forming opposing frame openings (16; 18) and comprises parallel layers of heat-emitting and heat-generating elements (10; 12) and a grid arrangement (20, 43) covering the respective frame openings (16; 18) and stiffening the housing (2). To simplify the manufacture of the electric heating device, and in particular with regard to larger tolerances that are to be permitted in the manufacture of the electric heating device, the present invention proposes that first struts (20) of the grid arrangement, extending perpendicular to the layers, are associated with the housing (2), and second struts (43), extending parallel to the layers, are formed by the heating block (8).Furthermore, the present invention provides a heat-generating element of an electric heating device comprising a positioning frame (28) made of an insulating material, which forms adjacent receptacles (32) for at least one PTC heating element (30) each, arranged between conductor tracks (34, 36) against which the PTC heating elements (30) are electrically conductive. A heat-generating element according to the present invention, which facilitates the assembly of the electric heating device, has a positioning frame comprising retaining webs surrounding and delimiting the conductor tracks, which overlap the conductor tracks on the outside.