Muffler Shell Cut-Off Portions for End Plate Insertion
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Solution Overview
Problem
Conventional mufflers face difficulties in smoothly inserting end plates into the shell main body due to interference caused by residual stress and twisted inner shell portions, leading to decreased productivity.
Innovation Solution
The muffler design includes cut-off portions at the inner end of the overlapped portion to prevent interference, allowing smooth insertion of end plates, with reduced diameter portions and specific axial and circumferential lengths to facilitate stable insertion and laser-welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the shell main body is formed by rolling a flat plate to create inner and outer shell portions with overlapped portions, then noise transmission is reduced, but the inner shell portion becomes twisted and projected inwardly due to residual stress, causing interference with end plate insertion
Solution Approach 1:
The invention extracts and removes the problematic inner shell portion at the opening side end by forming cut-off portions. This removes the twisted and projected inward portion that causes interference with end plate insertion, while preserving the noise-reducing double-layer structure in other areas of the shell main body
Solution Approach 2:
The invention segments the inner shell portion by forming cut-off portions that divide it into separate sections. This segmentation removes the interfering portion while maintaining the structural integrity and noise reduction functionality of the remaining shell structure
2Object-affected harmful factors
If the inner shell portion is twisted and projected inwardly due to residual stress, then the double-rolled structure maintains its noise reduction capability, but the end plates cannot be smoothly inserted into the openings
Solution Approach 1:
The invention extracts and removes the problematic twisted portion of the inner shell at the opening side by forming cut-off portions. This eliminates the interference that prevents smooth end plate insertion, thereby improving productivity without compromising the noise reduction capability of the double-rolled structure
3Shape
If the opening side end portion of the inner shell portion is clamped and rolled to form the shell main body, then the double-layer structure is created for noise reduction, but residual stress causes the inner shell portion to be projected inwardly
Solution Approach 1:
The invention removes the distorted inner shell portion at the opening side by forming cut-off portions, eliminating the visual and functional impact of residual stress distortion while preserving the stable double-layer structure in the main body of the shell
Solution Approach 2:
The invention applies local modification by forming cut-off portions only at the opening side end of the inner shell portion, where distortion occurs, while leaving the rest of the double-layer structure intact to maintain its noise reduction properties
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 design enables smooth and stable insertion of end plates, increasing productivity and allowing for consistent laser-welding along the entire circumference, enhancing the manufacturing efficiency of mufflers.
Implementation Method 1
The outer and inner shell portions 03 and 04 are partially overlapped to form overlapped portions 05, which are spot-welded together at several positions indicated by 06
Implementation Method 2
an outer peripheral portion of the end plates 02 and the end portions of the outer shell portion 03 are laser-welded or metal-insert-gas-welded along their outer circumferences 07
Implementation Method 3
an outer peripheral portion of the end plates 02 and the end portions of the outer shell portion 03 are laser-welded or metal-insert-gas-welded along their outer circumferences 07
Data Source
AI summary
A muffler includes a shell main that is formed in a cylinder with two openings opposite to each other being apart from each other in an axial direction of the shell main body by rolling a flat plate to have an overlapped portion overlapping an inner end portion and a shell portion, and a pair of end plates that are partially inserted in the openings of the shell main body and fixed to the shell main body. The inner end portion is formed with two cut-off portions at opening-side edges of the inner end portion, respectively, to avoid interference between the inner end portion and the end plates when the end plates are inserted into the openings of the shell main body.