PTC Heater Housing Assembly for Tolerance-Stable Heat Transfer
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Solution Overview
Problem
Existing electric heating devices with PTC elements face issues due to manufacturing tolerances and dimensional variations, leading to stress peaks, inefficient heat transfer, and overheating, which can break ceramic insulating layers and impair power current absorption.
Innovation Solution
The solution involves using a positioning frame with profile sections and tongue-and-groove joints to compensate for manufacturing tolerances, ensuring effective heat dissipation by connecting the PTC element to the receiving pocket through extruded aluminum profiles and elastic deformations, with adhesive filling for secure assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a wedge element is used to clamp the PTC element in the receiving pocket, then good thermal conductivity and heat dissipation are achieved, but stress peaks occur that can break the PTC element or ceramic insulating layer
Solution Approach 1:
The patent changes the geometric parameters of the receiving pocket by adding a counterbore (larger diameter section) at the insertion opening. This modifies the clamping mechanism from a pure wedge shape to a composite shape that distributes stress more evenly while maintaining thermal contact pressure, thus preventing breaks while ensuring heat dissipation.
Solution Approach 2:
The counterbore structure acts as a stress-distributing cushioning element that prepares the receiving pocket to accommodate dimensional variations and prevent stress concentration before the wedge element applies clamping force, thereby preventing breakage of fragile components.
2Ease of manufacture
If the receiving pocket has a downward-tapering cross-sectional shape to facilitate manufacturing, then production is simplified, but manufacturing tolerances cause misalignment between the pocket shape and PTC element dimensions leading to poor heat transfer
Solution Approach 1:
The receiving pocket is segmented into two functional zones: an upper counterbore section with larger diameter for accommodating dimensional variations and establishing initial contact, and a lower tapered section for precise positioning and clamping. This segmentation allows each zone to perform its specific function optimally despite manufacturing tolerances.
Solution Approach 2:
The receiving pocket combines two geometric forms (counterbore cylinder + tapered wedge) into a composite structure that leverages the advantages of both shapes: the counterbore provides tolerance compensation and the tapered section provides precise positioning and clamping force.
3Volume of moving object
If the clearance before inserting the wedge element is too small, then assembly is compact, but insufficient coverage of the heat dissipation surface causes overheating and reduced power current absorption
Solution Approach 1:
The patent extends the receiving pocket in the longitudinal dimension by adding a counterbore section, creating additional space for the PTC element's heat dissipation surface to be covered. This dimensional extension allows full thermal contact without increasing the transverse footprint excessively, maintaining compactness while improving energy absorption.
4Temperature
If the wedge element is made thicker to ensure coverage, then heat dissipation improves, but stress peaks increase that can cause breakage
Solution Approach 1:
The receiving pocket applies different geometric qualities to different regions: the counterbore section provides a larger contact area with distributed pressure for stress reduction, while the tapered section provides concentrated clamping force for effective heat transfer. This local differentiation optimizes both heat transfer and stress distribution.
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 approach maintains efficient heat transfer and power current absorption while compensating for manufacturing variations, preventing stress peaks and ensuring the PTC element's stability and longevity.
Implementation Method 1
PTC heating element with a positioning frame in which at least one PTC element is received
Implementation Method 2
ensuring effective heat dissipation by connecting the PTC element to the receiving pocket through extruded aluminum profiles
Data Source
Figure 1
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AI summary
The present invention relates to an electric heating device (2) with a housing (100) which forms a receiving pocket (102) in which at least one PTC heating device (2) with at least one PTC element (4) received in a positioning frame (10) and conductor tracks (6) electrically connected to the PTC element (4) with different polarity is received.The present invention aims to provide an electric heating device of the type mentioned above, which can compensate for manufacturing tolerances in an improved manner without significantly impairing the heat transfer from the PTC element and can be manufactured economically, and proposes to thermally connect at least one profile part (26) to the PTC element (4) on opposite main side surfaces, wherein the outer main side surfaces of the profile parts (26) opposite the PTC element (4) are thermally connected to an inner surface (136) of the receiving pocket (102) and wherein the profile parts (26) are connected to the positioning frame (10).