Welded Cooling Case Structure for Pressure-Stable Electrical Housings
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Solution Overview
Problem
The existing electrical devices with cases experience deformation and stress concentration at the joining portions due to the mechanical stress caused by the pressure of the cooling fluid in the flow path, which is elongated along the cover.
Innovation Solution
The case design includes a cover with extension portions that are divided into multiple parts, joined to the central and outer peripheral wall portions in an annular shape, and connected to the flow path, reducing stress concentration and preventing deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the flow path is elongated along the cover, then the cooling fluid can flow through the case, but the pressure of the cooling fluid creates mechanical stress on the joining portion causing deformation
Solution Approach 1:
The cover is divided into a main body and multiple extension portions that protrude into the flow path. This segmentation allows the extension portions to independently bear the pressure of the cooling fluid, distributing the mechanical stress away from the joining portion between the cover and main body, thereby preventing deformation while maintaining the cooling function.
Solution Approach 2:
The extension portions protrude from the cover in the arrangement direction (perpendicular to the cover surface) to define parts of the flow path. This dimensional change allows the flow path to be elongated without increasing the in-plane dimensions of the cover, while the extension portions bear the fluid pressure in the protruding direction, protecting the joining portion from stress.
2Reliability
If the cover is made to cover the recessed portion to form the flow path, then the cooling fluid can be contained, but the pressure applied to the cover causes deformation in the arrangement direction
Solution Approach 1:
The cover is segmented into a main body and multiple extension portions. The extension portions specifically bear the pressure of the cooling fluid in the arrangement direction, preventing the entire cover from deforming. Each extension portion acts as an independent pressure-bearing element that maintains the cover's overall shape stability.
Solution Approach 2:
The extension portions act as intermediary structures between the cooling fluid pressure and the main cover body. They absorb and distribute the fluid pressure, serving as a mediator that protects the joining portion and main cover from direct stress, thereby maintaining shape stability while containing the cooling fluid.
3Reliability
If the extension portion is continuous, then the flow path is smooth, but the stress concentration at the joining portion increases
Solution Approach 1:
The extension portion is divided into multiple separate extension portions arranged in the flow path direction. This segmentation creates multiple discrete pressure-bearing points along the flow path, distributing the stress from the cooling fluid across multiple locations rather than concentrating it at a single joining portion, while still maintaining flow path continuity.
Data Source
AI summary
An electrical device such as a power control apparatus comprises a case and at least one electrical component accommodated in the case. The case has a flow path for a cooling fluid. The flow path is formed between a bottom portion and a cover. The flow path is elongated generally along a U shape. The bottom portion and the cover are joined by welding. The cover is formed with protruding portions protruding into the flow path. The protruding portions have shapes to reduce stress concentration on welding portions. A stress caused by a pressure of the cooling fluid may acts on a distal end formed inside of the U shape in a concentration manner.