Method of forming a catalytic converter from a radially deformed pre-form member
A method is provided for manufacturing a catalytic converter. A metallic tubular member is provided. A section of the metallic tubular member is deformed radially inward to form a neck portion. The neck portion has a diameter less than an initial diameter of the metallic tubular member. The tubular member is separated at substantially an axial midpoint of the neck portion for obtaining a first pre-form member having a first conical-shaped end. At least one catalytic element is inserted in the first pre-form member. An outer surface of the first pre-form member is deformed radially inward for securing the catalytic element within the first pre-form member. The first pre-form member is spin-formed for forming a second conical-shaped end opposite the first conical-shaped end.
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 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. 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 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 must be loaded and unloaded in separate machines and have spin forming operations performed on both ends. In addition, if an imperfection exists in the metallic tubular member prior to the spin-form operation, this operation will enlarge the existing imperfection, thereby producing a defective component which must be scrapped due to the fracture in the component.
BRIEF SUMMARY OF THE INVENTIONThe present invention has the advantage of forming a catalytic converter assembly utilizing only one spin forming operation which provides cycle time reduction, cost savings, tooling wear, and scrap reduction. By utilizing only a single spin forming operation, time of manufacture is reduced. In addition, cost of tooling is reduced by the elimination of a spin forming machine. Furthermore, scrap is reduced as a result of the elimination of one of the two spin-forming operations which could otherwise enlarge existing fractures in the housing making the part unusable.
In one aspect of the present invention, a metallic tubular member is provided. A section of the metallic tubular member is deformed radially inward to form a neck portion by other than spin-forming. The neck portion has a diameter less than an initial diameter of the metallic tubular member. The tubular member is separated at substantially an axial midpoint of the neck portion for obtaining a first pre-form member having a first conical-shaped end. A catalytic element is inserted in the first pre-form member. An outer surface of the first pre-form member is radially deformed inward for securing the catalytic element within the first pre-form member. The first pre-form member is spin-formed for forming a second conical-shaped end opposite the first conical-shaped end.
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
At least one catalytic element 14 comprising a substrate and a support material is secured within an interior of the housing 12. An inner surface 16 of the housing 12 is pressed against the catalytic element 14 for securing the catalytic element 14 therein. Alternatively, the at least one catalytic element 14 may be stuffed into 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 the 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 as 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).
Each of the pre-forms include one conical-shaped end having a narrowed opening 46 and an opposing end 48 having a diameter substantially equal to the initial diameter of the tubular member 26.
The second pre-form member 44 and any additional pre-form members formed from the tubular member 26 are mounted to the spin forming machine 50 to form a respective second conical-shaped end of each additional pre-form member.
Radially deforming a first end of a respective housing section and spin forming a second end of the respective housing section reduces cost of tooling, time to manufacture, and scrap in comparison to spin-forming both ends of the respective housing section. Typically, a first dedicated machine is utilized to form the first conical-shaped end while a second dedicated machine is utilized to form the second conical-shaped end of the housing member. Elimination of the second spin forming operation eliminates the second dedicated machine which reduces tooling cost. Eliminating the second dedicated spin forming operation reduces time to manufacture which increases production output. Another advantage is the reduction of scrap and improved quality. Imperfections existing in the component end that is to be formed by spin forming will be enlarged by the spin form operation due to the rotation of the pre-form and spreading of the material during the spin-forming operation. Eliminating a spin form operation reduces the imperfections formed in the manufactured catalytic converter assembly enlarged by the spin forming operation. Lastly, since the neck portions are formed prior to cutting the tubular member, less material is required to be cut in the narrowed neck portion, and as a result, the tubular members may be cut faster and less (cutting) tooling wear is achieved.
In functional block 61, a section of the tubular member is deformed radially inward to form a neck portion.
In functional block 62, the deformed tubular member is separated at substantially the midpoint of the neck portion for obtaining a first pre-form member and a second pre-form member. Each pre-form member includes a first end that is conical-shaped with a collar portion having a narrowed opening and a second end having an opening where the opening includes a diameter substantially equal to the initial diameter of the tubular member.
In functional block 63, a catalytic element is inserted within the first pre-form member.
In functional block 64, the outer surface of the first pre-form member is deformed radially inward for securing the catalytic element within the first pre-form member.
In functional block 65, the first pre-form member with the catalytic element secured therein is mounted in a spin-forming machine for forming a second conical-shaped end.
In functional block 66, the catalytic converter assembly is removed from the spin-forming machine. The same steps may be repeated for manufacturing a second catalytic converter formed from the second pre-form member that are obtained in functional block 62.
In functional block 71, a plurality of neck portions are formed by deforming sections of the tubular member axially spaced from one another. The spacing between each of the neck portions are a predetermined length so that a sufficient amount of material is provided between the neck portions to allow each pre-form produced to be substantially the same size and length. This eliminates additional operations of having to remove additional material from the ends of the catalytic converter for forming same size housings.
In functional block 72, a plurality of tubular sections is obtained by cutting at substantially the midpoint of each neck portion. Each of the plurality of pre-form members includes a first end that is conical-shaped having a collar portion with a narrowed opening.
In functional block 73, the plurality of pre-form members is obtained by cutting at substantially the midpoint between each neck portion. Each of the pre-form members includes a second end having an opening where the diameter of the opening is substantially equal to the initial diameter of the tubular member.
Alternatively, step 73, may be performed before step 72.
In functional block 74, a catalytic element is inserted within a respective pre-form member.
In functional block 75, the outer surface of the respective pre-form member is radially deformed inward for securing the catalytic element within the respective pre-form member.
In functional block 76, the respective pre-form member having the catalytic element secured therein is mounted in a spin-forming machine and a second conical-shaped end is formed opposite the first conical-shaped end.
In functional block 77, the catalytic converter assembly is removed from the spin-forming machine.
In decision block 78, a determination is made whether any pre-form members formed earlier are available for manufacture and assembly into catalytic converter assemblies. If the determination made in decision block 74 is that an additional pre-form member requires manufacturing and assembly for forming a catalytic converter assembly, then a return is made to step 74 to assemble and manufacture a next catalytic converter assembly. If the decision in step 78 is made that no additional pre-forms are available, then a return is made to step 70 to form additional pre-form members.
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.
Claims
1. A method of manufacturing a catalytic converter comprising the steps of:
- providing a metallic tubular member;
- deforming a section of said metallic tubular member radially inward to form a neck portion, said neck portion having a diameter less than an initial diameter of said metallic tubular member;
- separating said tubular member at substantially an axial midpoint of said neck portion for obtaining a first pre-form member having a first conical-shaped end;
- inserting a catalytic element in said first pre-form member;
- deforming radially inward an outer surface of said first pre-form member for securing said catalytic element within said first pre-form member; and
- spin-forming said first pre-form member for forming a second conical-shaped end opposite said first conical-shaped end.
2. The method of claim 1 further comprising the steps of:
- providing a second pre-form member having a first conical-shaped end formed from said separation of said tubular member at said midpoint of said neck portion;
- inserting a respective catalytic element in said second pre-form member;
- deforming radially inward an outer surface of said second pre-form member that is radially aligned with said respective catalytic element for securing said respective catalytic element within said second pre-form member; and
- spin-forming said second pre-form member for forming a second conical-shaped end at an opposing end from said first conical-shaped end of said second pre-form member.
3. The method of claim 2 wherein said step of deforming a section of said metallic tubular member is performed by a swage operation.
4. The method of claim 2 wherein said swage operation includes a rotary swage operation.
5. The method of claim 2 wherein said step of deforming a section of said metallic tubular member is performed by a roll forming operation.
6. The method of claim 1 wherein said step of separating said tubular member at an axial midpoint is pre-formed by a laser cut operation.
7. The method of claim 1 wherein said step of separating said tubular member at an axial midpoint is pre-formed by a milling operation.
8. The method of claim 1 wherein said step of separating said tubular member at an axial midpoint is pre-formed by a cutting operation.
9. The method of claim 1 wherein metallic tubular is formed from wrapped sheep metal strip having a welded seam.
10. A method of manufacturing a plurality of catalytic converters from a metallic tubular member, said method comprising the steps of:
- (a) forming a plurality of axially spaced neck portions by deforming a section of said metallic tubular member, said plurality of axially spaced neck portions each having a diameter less than an initial diameter of said metallic tubular member;
- (b) cutting substantially a midpoint of said neck portions;
- (c) cutting substantially a midpoint between said neck portions;
- (d) inserting at least one respective catalytic element in a respective pre-form member;
- (e) deforming radially inward an outer surface of said respective pre-form member for securing said respective catalytic element within said respective pre-form member; and
- (f) spin-forming said respective pre-form member for forming a second conical-shaped end opposite said first conical-shaped end.
- repeating steps (d)-(f) for each respective pre-form member formed from said metallic tubular member.
11. The method of claim 10 wherein said step of forming said neck portions is performed by a swage operation.
12. The method of claim 11 wherein said swage operation includes a rotary swage operation.
13. The method of claim 12 wherein said step of forming said neck portions is performed by a roll forming operation.
14. The method of claim 10 wherein said step of separating said tubular member at an axial midpoint is pre-formed by a laser cut operation.
15. The method of claim 10 wherein said step of separating said tubular member at an axial midpoint is pre-formed by a milling operation.
16. The method of claim 10 wherein said step of separating said tubular member at an axial midpoint is pre-formed by a cutting operation.
17. The method of claim 10 wherein metallic tubular is formed from wrapped sheep metal strip having a welded seam.
Type: Application
Filed: Jun 23, 2006
Publication Date: Dec 27, 2007
Inventors: Haimian Cai (Ann Arbor, MI), Xiaojun Zhang (Canton, MI), Peng Xiao (Novi, MI)
Application Number: 11/474,200
International Classification: B21D 51/16 (20060101);