Vane Segment Mechanical Connection for Axial-Flow Machines
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Solution Overview
Problem
Existing vane segments in axial-flow fluid machines face issues with deformation or cracking due to thermal stress and require multiple assembly steps, including welding, which increases rattling between vanes.
Innovation Solution
A vane segment design featuring an outer connection member, positioning jigs, and radial restriction sections that connect vanes without welding, using grooves and holes to stabilize the vanes and reduce assembly steps, with eccentric positioning jigs to prevent falling and enhance stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If welding is used to connect vanes to the coupling member, then rattling between vanes is reduced, but deformation or cracking of the vane may occur due to thermal stress
Solution Approach 1:
The patent replaces the welding connection (thermal/mechanical system) with a mechanical interference fit connection. The coupling member is inserted into grooves formed in the outer shrouds of the vanes, creating a secure mechanical connection without thermal stress. This substitution eliminates the harmful thermal effects while maintaining the reliability of the connection.
2Strength
If welding is used to connect each vane to the coupling member, then connection strength is improved, but the number of assembly steps increases
Solution Approach 1:
The grooves are pre-formed in the outer shrouds of the vanes during manufacturing. The coupling member is designed with a shape that complements these grooves, allowing for preliminary positioning and alignment. This preliminary action enables a simple insertion operation that secures multiple vanes simultaneously, reducing assembly steps while maintaining connection strength.
Solution Approach 2:
The patent merges the connection of multiple vanes into a single operation. The coupling member connects all vanes in the vane segment simultaneously through a single insertion motion, rather than requiring separate welding operations for each vane. This merging of operations reduces assembly complexity while maintaining overall connection strength.
3Device complexity
If a simple groove connection is used to reduce assembly steps, then assembly complexity is reduced, but rattling between vanes increases
Solution Approach 1:
The coupling member is nested within the grooves formed in the outer shrouds of the vanes. The groove geometry is designed to provide lateral support to the coupling member, preventing rattling motion. The nested configuration creates a tight fit that secures the vanes in position while allowing for simple assembly through direct insertion.
Data Source
AI summary
A vane segment according to the present invention includes: an outer connection member connecting a plurality of vanes; positioning jigs for positioning end vanes located at both ends, of the plurality of vanes; and radial restriction sections which restrict the outer connection member so as to be relatively immovable to an outer side in a radial direction of a vane ring, wherein: each of the plurality of vanes has a vane main body and an outer shroud; grooves are formed in the outer shrouds; openings into each of which the positioning jig is inserted are formed in portions of the outer connection member; holes into each of which the positioning jig inserted in the opening is inserted are formed in bottoms of the grooves of the two end vanes; and at least one of the positioning jigs is an eccentric positioning jig.