Power Conversion Device Sealing for Assembly and Size
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Solution Overview
Problem
Existing power conversion devices face challenges in assembling workability and downsizing due to the complexity of waterproof sealing structures, which increase the surface area and require additional bolts for sealability, compromising the internal layout and size of the device.
Innovation Solution
The use of a combination of shaft seals and surface seals in contact with a casing lid that covers multiple opening portions, allowing for improved assembly workability and downsizing by simplifying the seal structure and reducing the number of necessary bolts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a surface seal structure is employed for openings in communication with one another, then waterproofness is achieved, but the surface area of the casing is increased and the layout of the internal structure is restricted
Solution Approach 1:
The seal structure is segmented into two distinct types: shaft seals for circular opening portions and surface seals for non-circular opening portions. This segmentation allows each seal type to be optimized for its specific opening shape, preventing the need to increase the casing surface area to accommodate a single universal seal design.
Solution Approach 2:
Different seal structures are applied to different opening portions based on their local characteristics. Circular openings use shaft seals while non-circular openings use surface seals, allowing each local area to have the most appropriate seal type for its geometry, thereby maintaining compact casing dimensions.
2Reliability
If a surface seal structure is employed, then waterproofness is achieved, but the number of bolts to be fastened is increased and workability of attaching the casing lid becomes poor
Solution Approach 1:
The sealing function is segmented between shaft seals and surface seals, with shaft seals providing both sealing and positioning functions for circular openings, reducing the need for additional bolts in those locations.
Solution Approach 2:
Shaft seals serve multiple functions: they provide waterproof sealing and simultaneously act as positioning elements for the casing lid, eliminating the need for separate positioning features and reducing the total number of fastening operations required.
3Ease of operation
If the plurality of openings are in communication with one another so as to be formed as one opening portion, then workability of attaching the casing lid is improved, but the shape of the seal becomes complicated and a surface seal needs to be used
Solution Approach 1:
Instead of creating one large complex surface seal to cover multiple openings, the patent segments the sealing approach by using individual shaft seals for each circular opening portion. This segmentation simplifies the seal shape while maintaining the benefit of covering multiple openings.
Solution Approach 2:
Rather than making all openings communicate to form one complex opening that requires a complex surface seal, the patent inverts the approach by maintaining separate opening portions that can be independently sealed with simpler shaft seals, achieving comparable workability without the complexity penalty.
Data Source
AI summary
Provided is a power conversion device that has improved assembling workability and that realizes downsizing thereof. The power conversion device includes: an electrical component; a casing enclosing the electrical component and terminals connected to the electrical component and an outside, the casing having a plurality of opening portions in which the terminals are disposed; and a casing lid covering the opening portions. A shaft seal provided so as to be in contact with a side surface contiguous with a rim of an opening portion among the opening portions, and a surface seal provided so as to be in contact with a surface contiguous with a rim of an opening portion among the opening portions, are disposed so as to be in contact with the casing lid.