Friction-Welded Impeller Assembly for Strong Low-Heat Joining
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Solution Overview
Problem
Existing impeller manufacturing methods, such as brazing and friction stir welding, face limitations in material selection and require high-temperature heating, which can alter material characteristics and restrict the use of certain metals like stainless steel, and result in unreliable joining strength.
Innovation Solution
The method involves joining the first and second disc portions of the impeller segments using friction welding, where the drive shaft applies rotational force and friction pressure to create a joining layer, allowing for strong bonding without heating the entire impeller to high temperatures, thus enabling the use of stainless steel and minimizing material characteristic variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If brazing is used to join the first segment and the second segment, then the joining strength is improved, but the material selection is restricted and high-temperature heating alters material characteristics
Solution Approach 1:
The patent replaces the thermal joining process (brazing) with a mechanical joining process (friction welding). Instead of using heat to join the segments, the invention uses mechanical friction generated by rotating one segment against the other while applying axial pressure, thereby substituting a thermal system with a mechanical system that avoids material characteristic alterations
Solution Approach 2:
The patent changes the fundamental parameter of the joining process from thermal energy (temperature) to mechanical energy (friction and pressure). By controlling mechanical parameters such as rotation speed, axial pressure, and friction time, the joining process achieves strong bonds without the high-temperature heating that limits material selection in brazing
2Strength
If brazing is used to join the first segment and the second segment, then the joining strength is improved, but the heating of the whole members to high temperature varies material characteristics
Solution Approach 1:
The patent replaces the thermal joining process (brazing) with a mechanical joining process (friction welding). Instead of using heat to join the segments, the invention uses mechanical friction generated by rotating one segment against the other while applying axial pressure, thereby substituting a thermal system with a mechanical system that avoids material characteristic alterations
Solution Approach 2:
The friction welding process creates heat and bonding only at the local joining surface between the two segments, rather than heating the entire members. This localized action preserves the material characteristics of the bulk material while achieving strong joining at the interface
3Adaptability or versatility
If friction stir welding is used to join the first segment and the second segment, then the material selection is improved for light metals, but the joining strength is unreliable for iron-based metal materials
Solution Approach 1:
The friction welding process described in the patent is universally applicable to various metal materials including iron-based alloys, stainless steels, and other materials that are difficult to join by friction stir welding. The mechanical friction-based joining mechanism works effectively across different material types, providing reliable joining strength for iron-based materials while maintaining versatility
4Manufacturing precision
If the impeller is configured as a single piece, then the flow path shape quality is improved, but the attachment and detachment of the impeller with respect to the rotary shaft becomes difficult
Solution Approach 1:
The patent divides the impeller into multiple segments (first segment with disc portion and second segment with cover and blades) that can be joined together. This segmentation allows the impeller to be assembled from separate components, facilitating easy attachment and detachment from the rotary shaft while maintaining high flow path quality through precise joining surfaces and tight tolerances
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach provides sufficient joining strength and maintains the accuracy and dimension precision of the impeller, while reducing thermal influence and deformation, and allows for faster manufacturing compared to traditional brazing methods.
Implementation Method 1
joining, by friction welding, the first disc portion of the first segment and the second disc portion of the second segment while a part of the first disc portion and a part of the second disc portion each corresponding to the joining layer abut on each other
Implementation Method 2
the drive shaft is rotated while friction pressure is applied between the first disc portion and the second disc portion through the drive shaft
Data Source
AI summary
An impeller 1 according to the present invention includes a disc portion 30 fixed to a rotary shaft 101 that rotates around an axis line O, a cover portion 50 disposed to face the disc portion 30, and a plurality of blade portions 40 provided between the disc portion 30 and the cover portion 50. The impeller 1 includes a first segment SG1 configured of a first disc portion 31 that is a portion of the disc portion 30 on one side of the axis line O, a second segment SG2 in which a second disc portion 35 that is a portion of the disc portion 30 on another side of the axis line O, the cover portion 50, and the blade portions 40 are integrally configured, and a joining layer CL configured to join, by friction welding, the first segment SG1 and the second segment SG2.