Muffler Shell Collar Forming for Curved Exhaust Openings
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for forming collars in transverse mufflers with highly curved muffler shells are prone to material rupture, deformation, and crenation, leading to unreliable and costly processes with potential for leaks and increased noise due to metal burrs.
Innovation Solution
A method using a collar forming head with movable expanders that rotates and expands to form a collar in one step, allowing for efficient and reliable collar formation without incremental steps, reducing the risk of cracks and deformations, and enabling a smooth, planar collar mouth for durable connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional stamping and drawing methods with multiple dies are used to form collars in highly curved muffler shells, then the collar can be formed incrementally, but the material cannot flow sufficiently causing extreme thinning and rupture, leading to cracks and requiring multiple process steps
Solution Approach 1:
The patent employs a dynamic expander tool that can change its diameter during the forming process. The expander starts with a small diameter to enter the exhaust gas opening, then gradually increases its diameter to form the collar in a controlled manner. This dynamic adjustment allows material to flow progressively without sudden stress concentration, preventing rupture and cracks while maintaining collar integrity.
Solution Approach 2:
The invention changes the geometric parameter of the expander tool (its diameter) during the forming process. By continuously varying the expander diameter from small to large, the method enables controlled material flow and gradual collar formation. This parameter change approach avoids the material thinning and rupture issues associated with traditional fixed-diameter stamping and drawing methods.
2Ease of manufacture
If multiple dies with increasing diameters are used in a step-by-step process, then collar formation can be incremental, but the process requires multiple steps and the muffler housing is not supported by baffles causing deformation
Solution Approach 1:
The patent implements a continuous collar forming process using a single expander tool that performs all forming operations in one continuous motion. The expander enters the exhaust gas opening, expands to form the collar, and completes the entire process without interruption or reversal. This eliminates the need for multiple discrete steps, reducing manufacturing cycle time while maintaining processability.
Solution Approach 2:
The method performs preliminary support preparation by ensuring the muffler housing is properly supported before the expander enters. The support structure is prepared in advance to prevent deformation during the collar forming process, eliminating the need for multiple steps to check and adjust support between operations.
3Device complexity
If traditional stamping methods are used to form collars, then the process can be simple, but the end circumference of the collar becomes crenated due to large deformations causing roughness and initiating cracks
Solution Approach 1:
The dynamic expander tool gradually increases its diameter during the forming process, allowing controlled material flow and progressive deformation. This gradual expansion prevents sudden large deformations that cause crenation, resulting in a smooth collar surface without initiating cracks, while the device itself remains relatively simple in design.
4Quantity of substance
If the collar diameter needs to fit large exhaust pipe diameters for high mass flow rates, then the collar diameter must be large, but in flat transverse mufflers the collar hole must be made on the side where the radius of curvature is very small making the process extremely difficult
Solution Approach 1:
The dynamic expander tool adapts to the curved surface by continuously adjusting its diameter during insertion and expansion. The expander enters with a small diameter to navigate the curved surface, then gradually expands to the required large diameter for high flow capacity. This dynamic adjustment makes collar formation feasible even in areas with very small radius of curvature.
Solution Approach 2:
The invention approaches the collar formation problem from the interior dimension by inserting the expander through the exhaust gas opening from inside the muffler. This internal approach allows the expander to work from the inside out, accommodating the external curvature constraints while achieving the required collar diameter for high exhaust gas flow capacity.
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 ensures reliable, leak-tight collar formation with reduced risk of cracks and deformations, eliminating the need for additional machining and minimizing noise from metal burrs, resulting in a more efficient and cost-effective manufacturing process.
Implementation Method 1
forming an outwardly projecting collar around the exhaust gas opening by flaring the edge of the metal sheet surrounding the exhaust gas opening outwardly and increasing the size of the exhaust gas opening
Data Source
AI summary
Method for forming a collar in a muffler shell including:providing a muffler shell made of a metal sheet and forming a muffler housing, the muffler shell having an exhaust gas opening,providing a collar forming head having a rotational axis and at least two movable expanders,introducing a collar forming head into a muffler housing,moving the expanders of the collar forming head introduced into the muffler shell radially away from the rotational axis of the collar forming head from a retracted position to an expanded positionrotating the collar forming head around the of the collar forming head,bringing the rotating expanded collar forming head in contact with the metal sheetforming an outwardly projecting collar around the exhaust gas opening by flaring the edge of the metal sheet.