PTC Electric Heating Device with Pressure Element Stress Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electric heating devices with PTC heating elements face issues due to dimensional fluctuations and manufacturing tolerances, leading to stress peaks, inefficient heat extraction, and potential damage to ceramic insulating layers, as the wedge-shaped pressure elements may not fit properly or provide sufficient coverage.
Innovation Solution
The introduction of deformation projections or webs that act in a positive-fit and/or force-fit manner to securely hold the pressure element in place, absorbing stress peaks and ensuring consistent heat extraction by bridging gaps between the PTC element's heat extraction surfaces and the receiving pocket's inner surfaces, with the option of integrally forming the pressure element and webs for simplified assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a wedge-shaped pressure element is used to hold the PTC element in the receiving pocket, then heat extraction is improved, but stress peaks occur and the PTC element or insulating layer may break due to manufacturing tolerances and dimensional fluctuations
Solution Approach 1:
The pressure element's geometry is changed from a simple wedge shape to include a recess at its end facing the PTC element. This geometric parameter modification allows the pressure to be distributed over a larger area, reducing stress peaks while maintaining effective heat extraction pressure.
Solution Approach 2:
The recess in the pressure element acts as a cushioning feature that absorbs and distributes stress before it reaches the PTC element and insulating layer. This preemptive design prevents stress concentration that would otherwise lead to breakage during assembly or operation.
2Ease of manufacture
If the receiving pocket tapers towards its lower closed end for production reasons, then manufacturing ease is improved, but the pressure element may not provide sufficient coverage or may be too thick depending on tolerances
Solution Approach 1:
The pressure element features a locally modified geometry with a recess at its end surface. This local quality change allows the pressure element to adapt to the tapered receiving pocket while ensuring uniform pressure distribution and adequate coverage regardless of dimensional variations in the tapered structure.
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 solution ensures resilient and effective heat extraction by maintaining a planar preload force, preventing damage to the PTC element and insulating layers, and enhancing the overall efficiency and reliability of the heating device.
Implementation Method 1
PTC heating element with at least one PTC element and conductor tracks abutting thereagainst in an electrically conductive manner
Implementation Method 2
holds heat extraction surfaces of the PTC element abutted against oppositely disposed inner surfaces of the receiving pocket
Data Source
AI summary
An electric heating includes a housing having a partition wall which separates a connection chamber from a heating chamber for dissipating heat and from which at least one receiving pocket, protruding into the heating chamber as a heating rib, preferably tapering towards its lower and closed end, protrudes. A PTC heating element, including at least one PTC element and conductor tracks for energizing the PTC element with different polarities, is accommodated in the housing with the conductor tracks being electrically conductively connected to the PTC heating element and being are electrically connected in the connection chamber. A pressure element is received in the housing and holds heat extraction surfaces of the PTC element abutted against oppositely disposed inner surfaces of the receiving pocket. To reduce mechanical stress on the PTC element or an insulating layer and, while at the same time retaining the PTC heating element in the receiving pocket, at least one web acts in a positive-fit and/or force-fit manner on the pressure element.