Metal Bushing Welding With Elastic Collar for Gas-Tight Joints
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Solution Overview
Problem
Resistance projection welding of metal bushings to exhaust system components often results in suboptimal welded joints due to uneven wall thickness and non-planar configurations, leading to reduced durability and potential gas leaks.
Innovation Solution
A method where a spring-elastic collar is formed around the component opening, allowing it to yield and compensate for manufacturing tolerances and deviations, ensuring a homogeneous weld connection by contacting a circumferential surface during resistance welding, eliminating the need for a weld boss on the bushing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If resistance projection welding is used to fasten the bushing to the component, then the bushing can be securely attached to the component, but the welded joint quality deteriorates due to uneven wall thickness and non-planar configurations in formed components
Solution Approach 1:
Instead of requiring the component to provide a perfectly planar and uniform contact surface, the invention inverts the approach by providing a planar contact surface on the bushing (through the planarized contact surface 5) that contacts the collar 7. This transfers the requirement for planarity from the component to the bushing assembly, resolving the contradiction between achieving reliable welding and dealing with formed component irregularities
Solution Approach 2:
The invention changes the physical state and geometry parameters of the contact interface by planarizing the contact surface 5 on the bushing and creating a collar 7 with specific geometric parameters. This allows the contact interface to maintain uniformity despite variations in the underlying component geometry, thereby improving welded joint quality while accommodating formed component characteristics
2Ease of manufacture
If a weld boss is provided on the bushing to facilitate welding, then the welding process can be simplified, but the device complexity increases and the spring-elastic compensation capability is reduced
Solution Approach 1:
The collar 7 acts as an intermediary element between the bushing 3 and the component 2. It provides the necessary contact surface for welding while allowing the bushing structure to remain relatively simple. The collar mediates the connection by providing both the welding interface and the spring-elastic compensation mechanism, eliminating the need for a complex weld boss structure on the bushing itself
Solution Approach 2:
The collar 7 serves multiple functions simultaneously: it provides a planar contact surface for welding, acts as an anvil for the welding process, and provides spring-elastic compensation for manufacturing tolerances. This multi-functionality eliminates the need for separate weld boss structures and other compensating mechanisms, thereby reducing overall device complexity while maintaining ease of manufacture
3Manufacturing precision
If the collar is made rigid to maintain precise geometric relationships, then the positioning accuracy is improved, but the ability to compensate for manufacturing tolerances is reduced
Solution Approach 1:
The collar 7 is designed with dynamic characteristics, being spring-elastic rather than completely rigid. This allows it to adapt its geometry within certain limits to accommodate manufacturing tolerances while maintaining sufficient positioning accuracy. The dynamic nature of the collar enables it to provide both tolerance compensation and adequate positioning, resolving the contradiction between rigidity and adaptability
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 method improves the quality and durability of the welded connection, reduces rework effort, and ensures a gas-tight seal, enhancing the reliability of exhaust system components under mechanical and thermal loads.
Implementation Method 1
the collar can yield in a resilient manner and thereby compensate for inequalities in the wall thickness and/or deviations from a plane in the circumferential direction along the collar
Implementation Method 2
heating is carried out in the contact area with the aid of an electric current, which is used to weld the bushing to leads to the component
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The present invention relates to a method for attaching a metallic bushing (3) to a metallic component (2), in which: - an annular contact surface (5) is formed on the bushing (3), - an opening (6) is formed on the component (2), - a collar (7) is formed on the component (2) extending around the opening (6) and projecting onto a mounting side (8) of the component (2) that is provided for attaching the bushing (3), - the bushing (3) is pressed against the mounting side (8) of the component (2) in the region of the opening (6) such that the contact surface (5) touches the collar (7), - the bushing (3) is pressed against the component (2) so that the contact surface (5) rests against the collar (7) under preload, - resistance welding is carried out while the contact surface (5) rests against the collar (7) under preload.so that the bushing (3) and component (2) are welded together in the area of contact between the contact surface (5) and the collar (7).