Joint-Site Structure for Friction Welding Thin-Walled Hollow Shafts
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Solution Overview
Problem
Existing joint-site structures for friction welding are inadequate for connecting thin-walled hollow shafts without additional support elements and often require subsequent machining due to insufficient radial support and misalignment issues, leading to inefficiencies and increased complexity.
Innovation Solution
A joint-site structure with coaxial insertion regions and radial undercuts that act as heat throttles and support ridges, ensuring reliable friction-weld connections without external support, while allowing contaminants and gases to escape, and maintaining coaxiality during the welding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional joint-site structures (stair-like or single-step configurations) are used for friction welding, then thick-walled hollow shafts can be connected, but thin-walled hollow shafts cannot be reliably welded due to insufficient radial support
Solution Approach 1:
The joint site is segmented into multiple coaxial insertion regions with different diameters, creating a multi-level step structure. This segmentation allows the weld material to be distributed across multiple zones, providing adequate radial support even for thin-walled components without requiring additional external support elements.
Solution Approach 2:
The invention transitions from a single-step joint configuration to a multi-step coaxial insertion structure, adding dimensional complexity to the joint site geometry. This multi-dimensional approach creates multiple radial support zones that collectively provide sufficient support for thin-walled hollow shafts during friction welding.
2Manufacturing precision
If stair-like joint-site structures are used to accommodate weld material, then weld beads can be contained, but excessive friction-welding material can still escape and enter the hollow shaft interior, requiring subsequent machining
Solution Approach 1:
The joint site is pre-configured with multiple coaxial insertion regions and step structures that create predetermined containment zones for weld material. This preliminary geometric preparation ensures that friction-welding material is contained within the joint site during the welding process, preventing escape into the hollow shaft interior and eliminating the need for subsequent machining operations.
3Manufacturing precision
If radial steps are formed to create free spaces for weld material, then weld beads can be accommodated, but the diameters must be precisely coordinated, and misalignment can occur during welding
Solution Approach 1:
The multi-step coaxial insertion structure serves multiple functions simultaneously: it creates free spaces for weld material containment, provides radial support for thin-walled components, maintains coaxial alignment during welding, and distributes thermal stresses. This universal joint site design eliminates the need for precise diameter coordination of single steps while achieving all necessary functions.
Solution Approach 2:
The step structures create predetermined clearance zones and cushioning spaces within the joint site that accommodate variations in alignment and dimensional tolerances. These pre-designed geometric features absorb misalignment stresses and maintain proper fit during the friction welding process, reducing the need for extremely precise diameter coordination.
4Reliability
If additional support elements are used to enable thin-walled shaft welding, then radial support is sufficient, but device complexity and manufacturing cost increase
Solution Approach 1:
The joint site structure itself provides the necessary radial support for thin-walled hollow shafts through its multi-step coaxial insertion geometry. The step structures create inherent radial constraints and support zones that eliminate the need for additional external support elements. The system serves itself by using its own geometric features to provide the support function.
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
Enables high-quality friction welding of thin-walled hollow shafts without additional support elements, ensuring reliable connections and minimizing post-processing requirements by maintaining coaxial alignment and controlling heat distribution effectively.
Implementation Method 1
the joining regions of the components to be connected with one another are structured in such a manner that after friction welding has taken place, they overlap coaxially
Implementation Method 2
the at least one step of the at least one component on which the axially set-back ring-shaped joining surface is situated is provided with a radial undercut in its throat region, which undercut offers an accommodation volume for friction-weld material
Data Source
AI summary
A joint-site structure for components to be connected by overlap friction welding. At least one step of at least one component, on which an axially set-back ring-shaped joining surface is situated, is provided with a radial undercut, in such a manner that on the face side, a region of this step that is unchanged in diameter forms a radial support ridge, which is connected with the at least one component by way of a heat throttle that is reduced in cross-section. The length of each step is designed in such a manner that when the face surface of the one component makes contact with the ring-shaped joining surface of the other component, the other face surfaces of these components, which surfaces lie opposite one another in the same radial position, are still exposed until completion of the friction-welding process.