Rubber Plug Lip Seal for Power Conversion Housing
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Solution Overview
Problem
The existing rubber plugs for power conversion equipment face challenges in achieving simultaneous assemblability, downsizing, lightening, waterproofing, and salt water resistance due to issues with flange thickness, clearance, and axial misalignment, which are not effectively addressed by current designs.
Innovation Solution
A casing and rubber plug design featuring a cylindrical core with a disc-shaped flange, lip seal, coaxial recessed section, tapered tip, and ribbed casing surface, where the rib height is greater than or equal to the flange thickness, allowing for improved axial misalignment absorption and insertion properties, minimizing flange diameter, and enhancing salt water resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the flange section of the rubber plug is thickened to enable holding by the assembly jig, then the assemblability is improved, but the rubber plug may be detached during operation
Solution Approach 1:
The rubber plug is divided into functionally distinct sections: a thickened flange section for assembly jig holding and positioning, and a thinner cylindrical seal section for sealing. This segmentation allows each section to be optimized for its specific function without compromising the other.
Solution Approach 2:
The flange section extends radially outward from the cylindrical seal section, creating a dimensional transition from a simple cylinder to a flanged structure. This radial extension provides the necessary holding surface for the assembly jig while maintaining the sealing integrity of the cylindrical portion.
2Object-affected harmful factors
If the cylindrical seal section is axially extended to improve salt water resistance, then the sealing performance is improved, but the casing thickness increases, preventing downsizing and lightening
Solution Approach 1:
The cylindrical seal section utilizes the flexibility and elasticity of rubber material to achieve effective sealing with minimal axial thickness. The rubber plug deforms to conform to the service hole opening, creating a reliable seal without requiring excessive axial extension.
Solution Approach 2:
The rubber plug combines the sealing properties of rubber with the structural support of the flange section, creating a composite structure that achieves both sealing performance and mechanical strength without increasing overall thickness.
3Ease of operation
If the flange diameter is increased to handle axial misalignment during simultaneous attachment, then the insertion property is improved, but the interval between rubber plugs increases, preventing downsizing
Solution Approach 1:
The tapered surface on the tip of the rubber plug creates a conical insertion geometry that guides the plug into the service hole. This tapered shape provides self-alignment capabilities, allowing the plug to automatically correct minor axial misalignments during insertion without requiring excessive flange diameter.
Solution Approach 2:
The rubber plug utilizes material elasticity and compressibility to accommodate axial misalignment during insertion. The rubber material deforms elastically to absorb positioning variations, enabling successful insertion even with slight misalignments while maintaining compact dimensions.
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
It is structured that plural service holes (3), each of which electrically joins a circuit in a casing (1) of a power conversion equipment, are provided on a surface of the casing, that a flange (4) of a rubber plug (2) for sealing the service hole has a lip seal (6) that abuts against the casing of the power conversion equipment, that a cylindrical recessed section (8) which is coaxial with a cylindrical seal surface (7) is provided in a central section of the rubber plug on an opposite surface from the lip seal (6) of the flange, that a tip of the rubber plug on a side not provided with the flange has a tapered surface (9), an insertion opening for the rubber plug in the service hole (3) has another tapered surface (10), that the surface of the casing is provided with a rib (11) on an outer circumference side of the flange (4) of the rubber plug, that an end surface of the rib is orthogonal to an axis (12) of the service hole, and that a relationship of h1 ≤ h2 is established when a distance from an abutment surface of the lip seal (6) to an end surface of the rubber plug on a side with the recessed section (8) is set as h1 and a distance from the abutment surface of the lip seal to the end surface of the rib (11) is set as h2.