PTC Heating Element Wedge Clamping for Low-Resistance Contact
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing heat-generating elements with PTC heating elements and conductor tracks face issues with low contact resistance and poor thermal efficiency, particularly at high operating voltages, due to inadequate mechanical contact and inefficient heat dissipation, leading to sluggish response to thermal changes and safety concerns from leakage currents.
Innovation Solution
A heat-generating element design featuring a housing that forms a structural unit with a wedge element, ensuring precise positioning and secure clamping of the PTC heating element between heat-emitting surfaces, with a wedge element having parallel and oblique surfaces to maintain contact pressure and facilitate heat dissipation, while minimizing leakage currents through insulating layers and sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metallic sleeve with silicone rubber coating is used to encapsulate the conductor track and PTC element, then electrical insulation is improved, but mechanical contact pressure between the conductor track and PTC element is insufficient
Solution Approach 1:
A compression element made of elastic material (such as silicone rubber or foam) is introduced as an intermediary between the insulating housing and the conductor track/PTC element assembly. This compression element applies continuous mechanical pressure to ensure good electrical contact while the housing provides electrical insulation, thus resolving the contradiction between insulation and contact pressure.
2Reliability
If the entire layer structure is surrounded by a press plate to build sufficient contact pressure, then electrical contact between conductor track and PTC element is improved, but heat dissipation from the PTC element becomes poor
Solution Approach 1:
The housing is segmented into different functional zones: one region provides compression for electrical contact (with the compression element), while other regions are designed for heat dissipation. The PTC element is positioned such that its lateral surfaces are exposed or in contact with heat-dissipating structures, separating the contact function from the heat dissipation function.
Solution Approach 2:
Different regions of the housing have different properties: the region contacting the conductor track and PTC element provides compression and insulation, while other regions are designed with thermal conductivity or surface features optimized for heat dissipation. The compression is localized to where electrical contact is needed, not applied uniformly across the entire structure.
3Loss of energy
If radiator elements are spring-loaded against the heat-generating element to improve heat dissipation, then thermal efficiency is improved, but leakage currents through the radiator element and frame cannot be avoided
Solution Approach 1:
Electrically insulating layers or coatings are applied to the radiator elements and frame structures that come into contact with the PTC element. This intermediary insulating layer allows thermal contact for heat dissipation while preventing electrical leakage currents, thus resolving the contradiction between heat transfer and electrical isolation.
4Reliability
If conductor tracks are made freely movable between radiator element and PTC element to apply spring force for contact, then electrical contact is improved, but current-carrying parts are exposed on the outside creating safety concerns
Solution Approach 1:
The conductor tracks are merged with or enclosed by the insulating housing structure. The housing serves dual functions: providing electrical insulation for safety and maintaining mechanical contact pressure on the PTC element. The conductor tracks are not freely movable but are securely positioned within the insulating housing, eliminating exposed current-carrying parts while maintaining reliable electrical contact.
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 enhances electrical contact and thermal efficiency by maintaining consistent contact pressure and effective heat dissipation, reducing thermal inertia and ensuring safety by minimizing leakage currents, making it suitable for high-voltage applications.
Implementation Method 1
the wedge element having a first wedge surface extending parallel to the conductor track and an exposed, second wedge surface aligned obliquely to the first wedge surface
Implementation Method 2
a heat-generating element with at least one PTC element
Implementation Method 3
the housing forms a structural unit with at least one of the conductor tracks and a wedge element... for heat dissipation
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention relates to a heat-generating element (1) for an electric heating device comprising at least one PTC heating element (8), conductive traces (12, 40) lying flat against it on both sides, and a frame (4) which forms at least one frame opening (6) for receiving the at least one PTC heating element (8). The present invention addresses the problem of providing a heat-generating element (1) in which good contact between the conductive trace (12, 40) and the at least one PTC heating element (8) can be ensured.To solve the problem, the present invention proposes to design the frame (4) as part of a housing (2) which forms a structural unit with a wedge element (48), wherein the wedge element (48) comprises a first wedge surface (50) extending parallel to the conductor track (12, 40) and a second wedge surface (52) exposed on the outside of the housing (2) and oriented obliquely to the first wedge surface (50). The present invention further provides an electric heating device having a heater housing which includes at least one pocket (110) for inserting the heat-generating element. For precise positioning of the heat-generating element (1) in the pocket (110), the heat-generating element has spacer surfaces (60, 62) upstream and downstream of the at least one PTC heating element (8) in the longitudinal direction of the pocket, by which adjacent heat-generating elements (1) are spaced apart from one another.In the further proposed method according to the invention for manufacturing the electric heating device, the at least one heat-generating element (1) is inserted into the pocket (110) up to a stop formed on the housing (2) and the heat-generating element (1) fixed in the pocket (110) is clamped between the PTC heating element (8) and the pocket (110) by moving the wedge element (48) relative to the PTC heating element (8) and the pocket (110).