Tap Changer Fixing Element with Strut Sections
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Solution Overview
Problem
Existing switching arrangements for tap changers face challenges in achieving high electrical insulation, flow permeability, and mechanical stability while being cost-effective, as they require numerous bores for flow permeability, which decreases mechanical stability and is time-consuming to manufacture.
Innovation Solution
A one-piece molded fixing element with an outer ring section and a central sleeve section connected via strut sections, providing high flow permeability and mechanical stability through strategically placed through-flow openings and a spider web-like structure, made from electrically insulating cast resin to ensure cost-effectiveness and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a large number of bores are drilled into the fixing element to achieve high flow permeability, then the flow permeability is improved, but the mechanical stability of the fixing element decreases
Solution Approach 1:
The fixing element is segmented into multiple functional zones: an outer ring section with contact rod bores, a central sleeve section for the switching shaft, and intermediate strut sections connecting them. This segmentation allows each zone to be optimized independently - the outer ring can have necessary bores for contact rods while the central and intermediate sections maintain structural integrity to support oil flow pathways without requiring excessive drilling.
Solution Approach 2:
The patent introduces radial strut sections that extend from the central sleeve to the outer ring, creating a three-dimensional structural framework. This adds a radial dimension to the design, allowing the fixing element to derive mechanical strength from the radial struts while maintaining axial flow pathways for oil circulation, thus resolving the contradiction between structural integrity and flow permeability.
2Quantity of substance
If a large number of bores are drilled into the fixing element to achieve high flow permeability, then the flow permeability is improved, but the manufacturing time increases
Solution Approach 1:
The patent merges multiple functional requirements into a single integrated fixing element design. The outer ring section, central sleeve section, and intermediate strut sections are combined into one component that simultaneously provides contact rod support, switching shaft accommodation, and oil flow pathways. This integration eliminates the need for separate drilling operations for multiple components and allows for more efficient manufacturing, likely through casting or similar processes.
3Quantity of substance
If the fixing element is designed with high flow permeability through multiple bores, then the oil flowability is improved, but the production cost increases
Solution Approach 1:
The patent changes the manufacturing approach from drilling multiple bores (subtractive manufacturing) to creating the fixing element through casting or molding (formative manufacturing). This parameter change in the manufacturing process allows the complex geometry with integrated flow pathways to be produced more efficiently, reducing labor costs and manufacturing time while maintaining the necessary flow permeability for oil circulation.
Data Source
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AI summary
The invention relates to a switching arrangement for a tap changer, comprising a plurality of contact rods (3), which are arranged parallel to each other, at a distance from each other, and in a circular shape around a central longitudinal axis (MLA) and which are supported by at least two fixing elements (2) that are spaced from each other, and a switching shaft (4), which extends along the central longitudinal axis (MLA) and which is rotatably supported in the fixing elements (2) about the central longitudinal axis (MLA) and which has a contact arrangement (5), wherein the fixing element (2) is a one-piece molded part, which comprises an outer ring section (6) having openings (7) for accommodating the contact rods (3) and a central first sleeve section (8) for rotatably accommodating the switching shaft (4), and wherein the central first sleeve section (8) is connected to the outer ring section (6) by means of brace sections (9).