Method of spin forming a catalytic converter
A method is provided of manufacturing a catalytic converter using a spin forming operation. At least one catalytic element is inserted in a tubular member. At least one spin forming wheel is provided for forming the tubular member. A force is applied to a first end section of the tubular member by the at least one spin forming wheel for forming a first conical-shaped end. A force is applied to a second end section of the tubular member by the at least one spin forming wheel for forming a second conical-shaped end. A force is applied by the at least one spin forming wheel to the outer surface of the tubular member between the first conical-shaped end and the second conical-shaped end for forming an indentation therebetween and preventing axial movement of the at least one catalytic element.
Not Applicable
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENTNot Applicable
REFERENCE TO A SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISC APPENDIXNot Applicable
BACKGROUND OF THE INVENTION1. Field of the Invention
This invention relates in general to catalytic converters, and in particular to a method of forming a catalytic converter.
2. Description of the Related Art
Catalytic converters typically include a catalytic element housed in a metallic housing. The housing includes a conical-shaped first end and a conical-shaped second end. The catalytic converters are typically manufactured by cutting a metallic tubular member to a desired length. In a known spin-form manufacturing method, the catalytic element is inserted within the housing and secured therein. The tubular member is loaded in a first spin forming machine to form the conical-shaped first end. After the first spin forming operation is completed, the partially formed tubular member is unloaded from the first spin forming machine and loaded onto a second spin forming machine to form the second conical-shaped end. A disadvantage to spin forming is that it is a time consuming process since the part is unloaded, re-orientated and loaded into a same machine for forming both ends. A second spin forming machine may be used to alleviate the bottle neck of having to unload and re-load the component at a same machine; however, this requires added cost of a second machine, tooling, and maintenance. In addition, if other processes such as swaging is used to secure the catalytic elements within the catalytic converter, then added cycle time, tooling, and component handling are required for these added operations.
BRIEF SUMMARY OF THE INVENTIONThe present invention has the advantage of forming a catalytic converter assembly utilizing only one spin forming operation per assembly which provides cost savings, tooling wear, and scrap reduction. By utilizing only a single spin forming operation, time of manufacture is reduced by the elimination of a second spin forming operation. In addition, cost of tooling is reduced by the elimination of a spin forming machine.
In one aspect of the present invention, a method is provided of manufacturing a catalytic converter using a spin forming operation. A metallic tubular member includes a substantially cylindrical outer surface and an inner surface. At least one catalytic element is inserted in the tubular member. An end of the metallic tubular member is loaded into a spin forming machine. At least one spin forming wheel is provided for forming the tubular member. A force is applied to a first end section of the tubular member by the at least one spin forming wheel for forming a first conical-shaped end. A force is applied to a second end section of the tubular member by the at least one spin forming wheel for forming a second conical-shaped end. A force is applied by the at least one spin forming wheel to the outer surface of the tubular member between the first conical shaped end and the second conical shaped end for forming an indentation therebetween and preventing axial movement of the at least one catalytic element.
In yet another aspect of the present invention, a method is provided for manufacturing a catalytic converter using a spin forming operation. A metallic tubular member is provided having a substantially cylindrical outer surface and an inner surface. At least one catalytic element is inserted in the tubular member. An end of the metallic tubular member is inserted into a spin forming machine. At least two spin forming wheels are spaced equally around the tubular member. A force is applied to the outer surface of the tubular member by the at least two spin forming wheels for securing the at least one catalytic element within the tubular member. A force is applied by the at least two spin forming wheels to the outer surface of the tubular member at a first end section and at a second end section for forming a first conical-shaped end and a second conical-shaped end.
In yet another aspect of the present invention, a method is provided of manufacturing a plurality of catalytic converters using a spin forming operation. A metallic tubular member is provided having a substantially cylindrical outer surface and an inner surface. The tubular member is separated into individual tubular sections. At least one catalytic element is inserted in a respective tubular section. An end of the respective tubular section is mounted to a spin forming machine. At least two spin forming wheels are equally spaced around the respective tubular section. A force is applied to the outer surface of the respective tubular section axially aligned with the at least one catalytic element by the at least two spin forming wheels for securing the at least one catalytic element within the respective tubular section. A force is applied to the outer surface of a first end and the outer surface of the second end of the respective tubular section by the at least two spin forming wheels for forming a first conical-shaped end and a second conical-shaped end. A force is applied to the outer surface of the respective tubular section between the first conical-shaped end and the second conical-shaped end for forming an indentation therebetween. Repeating the above assembly process of inserting catalytic elements in the respective tubular sections and spin forming each respective tubular section.
In yet another aspect of the present invention, a method is provided for manufacturing a plurality of catalytic converters using a spin forming operation. A plurality of catalytic elements are inserted in a metallic tubular member. A plurality of axially spaced neck portions are formed by at least two forming wheels. The plurality of neck portions each have a diameter less than an initial diameter of the metallic tubular member. A substantial midpoint of each neck portions is cut.
Various objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings.
Referring now to the drawings, there is illustrated in
The catalytic converter assembly 10 further includes a first catalytic element 14 and a second catalytic element 15 each comprising a substrate and a support material secured within an interior of the housing 12. Alternatively, the catalytic converter assembly 10 may include only one catalytic element or more than two catalytic elements. An inner surface 16 of the housing 12 is pressed against the first catalytic element 14 and the second catalytic element 15 for securing the first catalytic element 14 and second catalytic element from radial movement therein. An indentation 17 is formed between the first catalytic element 14 and the second catalytic element 15 for preventing axial movement of the first catalytic element 14 and the second catalytic element 15 within the housing 12.
The catalytic converter assembly 10 includes a first conical-shaped end 18 having a first port 20. The first port 20 is coupled to an exhaust pipe of a vehicle (not shown) extending from an internal combustion engine of the vehicle(not shown). The catalytic converter assembly 10 further includes a second conical-shaped end 22 having a second port 24. The second port 24 is coupled to a next portion of the exhaust system (not shown).
The first port 20 functions as an inlet port for receiving exhaust gases from the internal combustion engine such has hydrocarbons, carbon monoxide, and nitrogen oxides and converts the exhaust gases into carbon dioxide, water, nitrogen, and oxygen. The second port 24 functions as an exhaust port for discharging the converted gases to the discharging portion of the exhaust system (not shown).
A plurality of catalytic elements 31 are assembled into the interior of the tubular member 26. Preferably, the plurality of catalytic elements 31 are assembled in pairs such that each of the catalytic elements comprising a respective pair (e.g., first catalytic element 14 and second catalytic element 15) are spaced in close relation to one another. Each respective pair of catalytic elements are spaced at a predetermined distance from an adjacent pair of catalytic elements to allow respective conical-shaped ends to be formed on each side of a respective pair of catalytic elements. Alternatively, the catalytic elements may be equally spaced from one another so that a respective catalytic converter only includes a single catalytic element.
To prevent radial movement of the first catalytic element 14 and the second catalytic element 15 within the catalytic converter 10, the first and second spin forming wheels 42 and 44 apply a force to the outer surface 30 that is axially aligned (i.e., radially overlapping) with the first catalytic element 14 and the second catalytic element 15 for securing the inner wall 16 against the respective catalytic elements. This may include an indentation (similar to the indentation 17 used to prevent axial movement) to secure the first catalytic element 14 and the second catalytic element to prevent radial movement. This may be performed prior to or after the formation of the indentation 17. Alternatively, forming the indentation 17 and securing the catalytic elements to the inner surface 16 may be performed either before the tubular member 26 is separated into various catalytic converter assemblies or after the tubular member is separated into the respective catalytic converter assemblies; however, forming afterwards requires each respective catalytic converter assembly be reloaded into a spin forming machine.
In functional block 61, at least one catalytic element is inserted in the tubular member.
In functional block 62, an end of the tubular member is mounted in the spin forming machine having at least two spin forming wheels for forming the tubular member.
In functional block 63, a force is applied to a first end section of the tubular member by the at least two spin forming wheels for forming the first conical-shaped end. The at least two spin forming wheels are spaced equally around the tubular member for evenly supporting the tubular member and to apply an equal distribution of force when shaping the tubular member.
In functional block 64, a force is applied to a second end section of the tubular member by the at least two spin forming wheels for forming the second conical-shaped end. Since the at least two spin forming wheels are spaced equidistant around the tubular member for applying the equal distribution of force, the tubular member does not require additional support for the second end of the tubular member despite its overall length since support is provided by the at least two spin forming wheels.
In functional block 65, a force is applied by the at least two spin forming wheels to the outer surface of the tubular member between the conical-shaped ends to prevent axial movement of the at least one catalytic element within the catalytic converter.
In functional block 66, a force is applied to the outer surface of the tubular member of a region overlapping the at least one catalytic element for securing the at least one catalytic element within the catalytic converter and preventing radial movement of the catalytic elements. This force applied to the outer surface may produce an indentation to a portion of the overlapping region or the entire region overlapping the at least one catalytic element may be deformed for securing preventing radial movement.
In functional block 71, a plurality of catalytic elements are inserted in the tubular member. The plurality of catalytic elements are grouped in pairs so that the axial spacing between a designated pair of catalytic elements is less that the axial spacing between adjacent pairs of catalytic elements. This allows for a sufficient amount of material to be provided between the adjacent pairs of catalytic elements for forming the neck portions.
In functional block 72, an end of the tubular member is mounted in the spin forming machine having at least two spin forming wheels for forming the tubular member. The at least two spin forming wheels are spaced equally around the tubular member for applying an equal distribution of force at each contacting location and for evenly supporting the tubular member.
In functional block 73, a force is applied by the at least two spin forming wheels to respective sections on the outer surface of the tubular member that overlap the catalytic elements for securing the catalytic elements within the catalytic converter and preventing radial movement of the catalytic elements.
In functional block 74, a force is applied by the at least two spin forming wheels to respective sections of the outer surface located between adjacent pairs of catalytic elements for forming a plurality of neck portions.
In functional block 75, a force is applied by the at least two spin forming wheels to respective regions of the outer surface located between a respective pair of catalytic elements for forming an indentation therebetween for preventing axial movement of the catalytic elements within the catalytic converter.
In functional block 76, separating the tubular member at substantially the axial midpoint of each neck portion for forming a plurality of catalytic converters.
In accordance with the provisions of the patent statutes, the principle and mode of operation of this invention have been explained and illustrated in its preferred embodiment. However, it must be understood that this invention may be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope. For example, the steps of shaping each of the respective regions of the catalytic converter may interchanged such that one region may be formed before other regions. In addition, the tubular member may be separated prior to inserting the catalytic elements and spin forming each respective tubular section for shaping each catalytic converter.
Claims
1. A method of manufacturing a catalytic converter using a spin forming operation, said method comprising the steps of:
- providing a metallic tubular member having a substantially cylindrical outer surface and an inner surface;
- inserting at least one catalytic element in said tubular member;
- loading an end of said metallic tubular member into a spin forming machine;
- providing at least one spin forming wheel for forming said tubular member;
- applying a force to a first end region of said tubular member by said at least one spin forming wheel for forming a first conical-shaped end;
- applying a force to a second end region of said tubular member by said at least one spin forming wheel for forming a second conical-shaped end; and
- applying a force by said at least one spin forming wheel to said outer surface of said tubular member between said first conical-shaped end and said second conical-shaped end for forming an indentation therebetween and preventing axial movement of said at least one catalytic element.
2. The method of claim 1 further comprising the steps of:
- applying a force by said at least one spin forming wheel to said outer surface of said tubular member that is axially aligned with said first catalytic element for securing said at least one catalytic element.
3. A method of manufacturing a catalytic converter using a spin forming operation, said method comprising the steps of:
- providing a metallic tubular member having a substantially cylindrical outer surface and an inner surface;
- inserting at least one catalytic element in said tubular member;
- loading an end of said metallic tubular member into a spin forming machine;
- positioning at least two spin forming wheels equally spaced around the tubular member;
- applying a force to said outer surface of said tubular member by said at least two spin forming wheels for securing said at least one catalytic element within said tubular member; and
- applying a force by said at least two spin forming wheels to said outer surface of said tubular member at a first end region and at a second end region for forming a first conical-shaped end and a second conical-shaped end.
4. The method of claim 3 wherein said step of applying a force to said outer surface includes applying an equally distributed force by said at least two spin forming wheels to said outer surface that is axially aligned with said at least one catalytic element for securing said at least one catalytic element within said tubular member.
5. The method of claim 4 wherein said step of applying a force to said outer surface further includes applying an equally distributed force by said at least two spin forming wheels to said outer surface of said tubular member between said first conical-shaped end and said second conical-shaped end for forming an indentation therebetween and preventing axial movement of said at least one catalytic element.
6. The method of claim 5 wherein said first conical shaped-end, said second conical-shaped end, said midsection, and said outer surface co-axially aligned with said catalytic elements are formed by a continuous spin-forming operation.
7. The method of claim 6 wherein said first conical shaped-end, said second conical-shaped end, said midsection, and said outer surface co-axially aligned with said catalytic elements are formed by discrete spin forming operations.
8. The method of claim 3 wherein said force applied to said first end region and said second end region to form said first conical-shaped end and said second conical-shaped end is substantially equally distributed by said at least two spin forming wheels.
9. The method of claim 3 wherein only said tubular member is rotated during said spin forming operation.
10. The method of claim 3 wherein only said at least two forming wheels are rotated during said spin forming operation.
11. The method of claim 3 wherein said tubular member is rotated during said spin forming operation and said at least two forming wheels are rotated about said tubular member during said spin forming operation.
12. A method of manufacturing a plurality of catalytic converters using a spin forming operation, said method comprising the steps of:
- (a) providing a metallic tubular member having a substantially cylindrical outer surface and an inner surface;
- (b) separating said tubular member into individual tubular sections;
- (c) inserting at least one catalytic element in a respective tubular section;
- (d) mounting an end of said respective tubular section to a spin forming machine;
- (e) positioning at least two spin forming wheels equally spaced around the respective tubular section;
- (f) applying a force to said outer surface axially aligned with said at least one catalytic element by said at least two spin forming wheels for securing said first catalytic element and said second catalytic element within said respective tubular section;
- (g) applying a force to said outer surface of a first end and said outer surface of said second end of said respective tubular section by said at least two spin forming wheels for forming a first conical-shaped end and a second conical-shaped end;
- (h) applying a force to said outer surface region of said respective tubular section between said first conical-shaped end and said second conical-shaped end for forming an indentation therebetween; and
- (i) repeating steps (c)-(h) for each respective tubular section.
13. The method of claim 12 wherein a respective internal cone is inserted in each end of said tubular section prior to step (d).
14. The method of claim 12 wherein during step (g) after said first conical-shaped end is formed, said respective tubular section is un-mounted from said spin forming machine and mounted at an opposite end of said respective tubular section for forming said second conical-shaped end.
15. The method of claim 12 wherein said first conical shaped-end, said second conical-shaped end, said indentation, and said respective tubular section axially aligned with said catalytic elements are formed by a continuous spin-forming operation.
16. The method of claim 12 wherein said first conical shaped-end, said second conical-shaped end, said indentation, and said respective tubular section axially aligned with said catalytic elements are formed by discrete spin forming operations.
17. The method of claim 12 further comprising the step of removing a desired length of material from at least one of said conical-shaped ends.
18. The method of claims 12 wherein said forces applied to said tubular section to form said first conical-shaped end, said second conical-shaped end, said indentation, and said respective tubular section axially aligned with said catalytic elements are equally distributed by said at least two spin forming wheels.
19. The method of claim 12 wherein said metallic tubular member is formed from wrapped sheet metal strip having a welded seam.
20. The method of claim 12 wherein said metallic tubular member is formed from an extrusion process.
21. A method of manufacturing a plurality of catalytic converters using a spin forming operation, said method comprising the steps of:
- (a) inserting a plurality of catalytic elements in a metallic tubular member;
- (b) forming a plurality of axially spaced neck portions by at least two spin forming wheels, said plurality of neck portions each having a diameter less than an initial diameter of said metallic tubular member; and
- (c) cutting substantially a midpoint of said neck portions.
22. The method of claim 21 wherein during step (b) a force is applied by said at least two spin forming wheels to an outer surface region of said tubular member that is axially aligned with said plurality of catalytic elements for securing said plurality of catalytic elements within said tubular member.
23. The method of claim 22 wherein during step (b) a force is applied said at least two forming wheels to said outer surface of said respective tubular region between said plurality of axially spaced neck portions for forming respective indentations therebetween for preventing axial movement of said catalytic elements.
24-28. (canceled)
Type: Application
Filed: Jun 23, 2006
Publication Date: Jan 3, 2008
Inventors: Haimian Cai (Ann Arbor, MI), William Koivula (Milford, MI)
Application Number: 11/474,189
International Classification: B21D 51/16 (20060101);