Method and apparatus for manufacturing a muffler for automotive exhaust systems
A method of manufacturing a muffler for an automotive vehicle includes providing an interior subassembly including spaced apart end plates and flow tubes extending generally perpendicular to the end plates. A leading edge of a metal sheet is clamped against the interior subassembly and the sheet is welded proximal the leading edge, to the interior subassembly. The interior subassembly is rotated while maintaining tension on the sheet, thereby causing the sheet to wrap around the interior subassembly as the interior subassembly rotates and the sheet is welded at an intermediate location to the interior subassembly. The rotating of the interior subassembly is repeated and the sheet is welded proximal a trailing edge thereof to one of the interior subassembly and an underlayer of the sheet. The subassembly is then rotated and the sheet is continuous seem welded to the end plates.
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The present invention relates to the manufacture of muffler or silencer devices for use in automotive exhaust systems.
BACKGROUND OF THE INVENTIONMufflers are employed in automotive exhaust systems for reducing the sound from an automotive exhaust. These mufflers commonly include an inner space defined by an outer shell and end plates. The inner space is divided into chambers by interior baffles that are generally parallel with the end plates and flow tubes join the chambers and exhaust the gas. The manufacture of these mufflers involves a number of steps in a manufacturing line that requires significant floor space.
An outer shell is created by wrapping a sheet of metal around a mandrel to provide the desired size and shape and the ends of the sheet of metal are locked together in a lock seam by folding one side over the other and then folding the seam along the surface of the outer shell. Outer flanges are then formed at either end of the outer shell by bending the outer edges outwardly.
The flow tubes are inserted into apertures of the baffles and the flow tubes and baffles are fixed together such that the flow tubes run generally perpendicularly to the baffles. The baffles and flow tubes are inserted into the outer shell such that the baffles are generally parallel to each other and the outer shell spot welded to the baffles to fix the interior components in place. For a muffler with more than two baffles, the first two baffles and flow tubes are first inserted and the spot welded into place. Additional baffles are then inserted and spot welded to the outer shell.
End plates are then placed at each end of the outer shell and the edge of each end plate is folded over along the surface of the outer shell to form a mechanical lock joint. Each end plate includes an aperture through which respective flow tubes extend from the interior of the muffler.
While such manufacturing methods produce a generally acceptable product, the manufacturing line includes several steps requiring extensive floor space. Further, each muffler shape and size requires a different mandrel for forming the shell and different tooling for each step of the process.
SUMMARY OF THE INVENTIONAccording to one aspect of an embodiment, there is provided a method of manufacturing a muffler for an automotive exhaust, including providing an interior subassembly including spaced apart end plates, at least two baffles generally parallel with the end plates and located therebetween, and flow tubes extending generally perpendicular to the baffles and end plates. A leading edge of a metal sheet is clamped against the interior subassembly and the sheet is welded proximal the leading edge, to the interior subassembly. The interior subassembly is rotated while maintaining tension on the sheet, thereby causing the sheet to wrap around the interior subassembly as the interior subassembly rotates and the sheet is welded at an intermediate location to the interior subassembly. The rotating of the interior subassembly is repeated and the sheet is welded proximal a trailing edge thereof to one of the interior subassembly and an underlayer of the sheet.
According to another aspect, there is provided an apparatus for manufacturing a muffler for an automotive exhaust. The apparatus includes a housing, a mounting mechanism including a turning device coupled to the housing for holding an interior subassembly of the muffler and for rotating the interior subassembly. A sheet feeder is connected to the housing for feeding a sheet of metal in alignment with and adjacent the interior subassembly and a clamping apparatus cooperates with the sheet feeder for clamping a leading edge of a sheet against the interior subassembly when the sheet is fed to the subassembly. A welding apparatus is used for welding the sheet to the interior subassembly and control equipment controls rotation of the interior subassembly while the sheet feeder maintains tension on the sheet, thereby causing the sheet to wrap around the interior subassembly as the interior subassembly rotates, and for controlling welding of the sheet.
Thus, an interior subassembly is first manufactured. The remaining steps of the process are carried out in the apparatus, therefore requiring fewer stops along a manufacturing line and less floor space. Advantageously, the chucks can be interchanged using, for example, a collet arrangement, to allow for the manufacture of a different muffler size or shape using the apparatus. Similarly, the control equipment can be programmed to carry out each step for different muffler types.
In one particular embodiment, the apparatus includes a lateral translation mechanism for laterally translating the chuck during rotation thereof. Thus, the interior subassembly is moved laterally during rotation to allow for the manufacture of muffler shapes that are not round in cross-section. The lateral translation is controlled to ensure that the laser welder is at the same angle to the sheet as the sheet is wrapped around the interior subassembly. In another aspect, the leading edge of the metal sheet is clamped against the interior subassembly with a clamp bar and a roller clamp is used to force a trailing portion of the sheet against the interior subassembly. The sheet is welded proximal the leading edge, between the clamp bar and the roller clamp, to the interior subassembly. The interior subassembly is rotated while maintaining tension on the sheet to cause the sheet to wrap in a tight fit around the interior subassembly.
The present invention will be better understood with reference to the drawings and to the following description, in which:
Reference is first made to
Continued reference is made to
A feeder mechanism 40 is fixed to the frame structure 36 for feeding an interior subassembly into the mounting mechanism 24. The feeder mechanism includes a feeder nest 42 for receiving the interior subassembly and for loading the interior subassembly into the mounting mechanism 24. The feeder nest 42 includes a carriage 44 with a clamp bar 46 on an upper portion thereof. The carriage 44 is driven vertically between machine loading, chuck loading and bottom clamping positions, and supported by bearings. The clamp bar 46 provides support to an undersurface of the interior subassembly when the carriage 44 is in the bottom clamping position during manufacturing.
The feeder nest 42 includes two brackets 47 for receiving opposing tooling plates 48, each with a cutout profiled to snuggly fit the bottom portion of each end plate of the interior subassembly. Each tooling plate 48 includes a lip interior to the subassembly at the face of the respective end plate that faces the baffles, for supporting the respective end plate when the interior subassembly is loaded onto the tooling chucks 26, 27. The brackets 48 are connected together by a lead screw 45 that is connected to a motor for adjusting the pitch between the tooling plates 48 such that the lip on each tooling plate closely contacts the interior side of each end plate of the interior subassembly during feeding. The brackets 48 are also fixed to a horizontal drive 49 for pulling the interior subassembly onto the fixed-side tooling chuck 26. Adjustment and operation of the feeder mechanism 40 is controlled by the control equipment 34.
The mounting mechanism 24 is fixed within the frame structure 36 and cooperates with the feeder mechanism 40 for receiving the interior subassembly of the muffler. The mounting mechanism 24 includes a turning device 50 for rotation of the interior subassembly when loaded into the mounting mechanism 24. The turning device 50 includes a pair of rotatable chucks 26, 27, both powered by respective motors connected to the control equipment 34 to control rotation of the chucks 26, 27 and to thereby control the rotation of the interior subassembly when loaded into the mounting mechanism 24. Rotation of the rotatable chucks 26, 27 is synchronized by the control equipment 34. The rotatable chucks 26, 27 include one fixed-side tooling chuck 26 and a moving-side tooling chuck 27. The fixed-side tooling chuck 26 is fixed with respect to movement along the axis of rotation of the tooling chucks 26, 27 while the moving-side tooling chuck 27 is movable longitudinally along the axis of rotation of the tooling chucks 26, 27. A rack and pinion driven by a motor, are responsible for longitudinal movement and positioning of the moving-side tooling chuck. Movement along the axis of rotation of the tooling chucks 26, 27 permits advancement of the moving-side tooling chuck 27 toward the fixed-side tooling chuck 26 when the interior subassembly is loaded into place, in order to clamp the interior subassembly in the tooling chucks 26, 27. The tooling chucks 26, 27 include a collet arrangement for replacement of the tooling chucks 26, 27 within the turning device 50. Thus, alternative tooling chucks 26, 27 can be used for alternative muffler shapes and sizes.
The mounting mechanism 24 also includes a lateral translation mechanism 54 for lateral translation of the turning device 50, perpendicular to the axis of rotation of the turning device 50 during manufacturing of the muffler. The turning mechanism 50 is fixed to the lateral translation mechanism 54, which in turn is fixed to the support frame structure 36. The lateral translation mechanism 54 includes a servomotor coupled to a ball screw assembly at each side (fixed side and moving side) of the turning device 50 while linear bearings guide the lateral translation. The control equipment 34 is responsible for synchronizing the servomotors at each side of the turning device 50. Lateral translation provides for the manufacture of muffler devices that are not round in cross-section as the lateral translation is controlled to ensure that the beam from the laser welding apparatus 32 is at a consistent angle with respect to the interior subassembly during certain manufacturing steps of the muffler.
Referring still to
A clamping apparatus 30 is fixed to the support frame structure 36 and cooperates with the sheet feeder 28 for clamping the sheet of metal against the interior subassembly during manufacturing of the muffler. The clamping apparatus 30 includes a vertical drive controlled by the control equipment 34 for advancing a clamp bar 64 to clamp a leading edge of the sheet of metal against the interior subassembly when the leading edge is fed to the interior subassembly by the sheet feeder 28.
A second clamping apparatus 68 is also fixed to the support frame structure 36 for clamping the sheet of metal against the interior subassembly during manufacture. The second clamping apparatus 68 also includes a vertical drive controlled by the control equipment 34 for advancing a roller 72 to clamp a trailing portion of the sheet metal against the interior subassembly. The roller 72 contacts the sheet of metal on the trailing side of the clamp bar 64, between the sheet feeder 28 and the clamp bar 64. The vertical drive of the second clamping apparatus 68 is separately operable from the vertical drive of clamping apparatus 30. Thus, the roller 72 is separately engageable with the sheet of metal during manufacture. The roller 72 and clamp bar 64 are spaced apart to permit welding of the sheet to the interior subassembly at points located between the roller 72 and the clamp bar 64.
The welding apparatus 32 is located on the upper platform 38 of the housing 22 for accessibility from the upper platform 38, and is controlled by the control equipment 34. As will be understood by those skilled in the art, the welding apparatus 32 is a remote laser welder including a laser resonator 76 and a scanner 78 for directing a laser welding beam (non-visible, far infrared) to desired locations along the sheet of metal on the interior subassembly. It will be appreciated that the laser resonator 76 produces the laser beam while the scanner 78, which includes lens and mirror actuators, focuses and directs the beam to the desired location. Simple trigonometric relationships control the lens and mirror actuators according to the effective radius of the muffler at the point of weld, and the location of the weld along the longitudinal axis of the muffler.
The control equipment 34 is connected to each of the feeder mechanism 40, the mounting mechanism 24, the sheet feeder 28, the two clamping apparatus 30, 68, and the welding apparatus 32 for control and timing of operation of each. In the present embodiment, the control equipment 34 includes programmable devices, the coding of software for which is well within the scope of a person of ordinary skill in the art.
In use, an interior subassembly for a muffler is loaded into the feeder mechanism 40 by loading into the feeder nest 42 from preassembly, as shown in
Referring now to
Next, the moving-side tooling chuck 27 is moved toward the fixed-side tooling chuck 26, to clamp the interior subassembly 100 between the tooling chucks 26, 27, as shown in
After loading the interior subassembly 100, the tooling chucks 26, 27 are rotated and translated to thereby rotate and translate the interior subassembly 100 into a first welding position.
Next, a metal sheet 110 that is precut to a specified size and length to form an exterior shell of the muffler is fed by the sheet feeder 28 to a start position as shown in
Referring to
The roller 72 is then advanced by the vertical drive to pinch a trailing portion of the metal sheet 110 between the roller and the interior subassembly 100, as shown in
Referring now to
Referring now to
The interior subassembly 100 is rotated by the turning device 50 to a next weld position, as depicted in
After spot welding at the intermediate positions, the metal sheet 110, which is now wrapped around the interior subassembly 100, is continuous-seam welded to the recessed portions of each of the end plates 104, as depicted in
Next, the trailing edge of the metal sheet 110 is continuous seam welded to an underlayer of the same metal sheet 110, as shown in
After welding of the trailing edge of the metal sheet 110, the roller 72 is removed from contact with the muffler and the muffler is rotated and translated to an unload position (
While the embodiment described herein is directed to a particular implementation of the method and apparatus for manufacturing a muffler for an automotive exhaust, it will be understood that modifications and variations to this embodiment are within the sphere and scope of the present application. For example, rather than continuous seam welding the trailing edge to an underlayer of the metal sheet as described above, the metal sheet can be wrapped around the interior subassembly more than one time and the trailing edge of the metal sheet can be laser spot welded to the underlayer of the metal sheet. Thus, rather than a continuous weld seal, a labyrinth seal is formed by wrapping the interior subassembly with the metal sheet more than one time. Also, the size and shape of many of the features can vary. Further, many of the features can be replaced by other features for carrying out similar functions.
Many other modifications and variations may occur to those skilled in the art. All such modifications and variations are believed to be within the sphere and scope of the present application.
Claims
1. A method of manufacturing a muffler for an automotive exhaust, comprising:
- providing an interior subassembly comprising spaced apart end plates, and flow tubes extending generally perpendicularly to the end plates;
- clamping a leading edge of a sheet against the interior subassembly;
- welding said sheet proximal said leading edge, to said interior subassembly;
- rotating the interior subassembly while maintaining tension on the sheet, thereby causing the sheet to wrap around the interior subassembly as the interior subassembly rotates;
- welding the sheet at an intermediate location to said interior subassembly;
- repeating said rotating the interior subassembly;
- welding said sheet proximal a trailing edge thereof to an underlayer of said sheet.
2. The method according to claim 1, comprising repeating said rotating the interior subassembly and welding the sheet at said intermediate location at least once.
3. The method according to claim 1, wherein clamping said leading edge comprises pinching a portion of said sheet proximal said leading edge between a clamp bar and said interior subassembly.
4. The method according to claim 1, comprising forcing a trailing portion of said sheet against said interior subassembly, prior to welding said sheet proximal said leading edge.
5. The method according to claim 3, comprising applying said force against said sheet, on a trailing side of said clamp bar by pinching a trailing portion of said sheet between a roller clamp and said interior subassembly, prior to welding said sheet proximal said leading edge.
6. The method according to claim 5, wherein said welding said sheet proximal said leading edge comprises laser spot welding said sheet to said end plates and to baffles located between said end plates, between said clamp bar and said roller clamp.
7. The method according to claim 1, wherein rotating the interior subassembly includes laterally translating said interior subassembly.
8. The method according to claim 1, comprising continuous seam welding said sheet to each of said end plates.
9. The method according to claim 1, wherein welding said sheet proximal a trailing edge thereof comprises continuous seam welding said sheet proximal said trailing edge.
10. The method according to claim 1, comprising continually applying a force against a trailing portion of said sheet to pinch said trailing portion against said interior subassembly during welding said sheet proximal said leading edge, rotating the interior subassembly, and welding said sheet at said intermediate location.
11. An apparatus for manufacturing a muffler for an automotive exhaust:
- a housing
- a turning device coupled to said housing for holding an interior subassembly of said muffler and for rotating said interior subassembly;
- a sheet feeder connected to said housing for feeding a sheet of metal in alignment with and adjacent said interior subassembly;
- a clamping apparatus cooperating with said sheet feeder for clamping a leading edge of a sheet against the interior subassembly when said sheet is fed to said subassembly;
- a welding apparatus for welding said sheet to said interior subassembly; and
- control equipment for controlling rotation of the interior subassembly while the sheet feeder maintains tension on the sheet, thereby causing the sheet to wrap around the interior subassembly as the interior subassembly rotates, and for controlling welding of the sheet.
12. The apparatus according to claim 11, wherein said clamping apparatus comprises a clamp bar for clamping said leading edge of said sheet against said interior subassembly.
13. The apparatus according to claim 11, comprising a second clamping apparatus for forcing a trailing portion of said sheet against the interior subassembly.
14. The apparatus according to claim 13, wherein said second clamping apparatus comprises a roller clamp.
15. The apparatus according to claim 11, wherein said welding apparatus comprises a laser welding apparatus.
16. The apparatus according to claim 13, wherein said welding apparatus comprises a laser welding apparatus and said laser welding apparatus is located for directing a laser weld beam between said clamping apparatus and said second clamping apparatus.
17. The apparatus according to claim 11, wherein said rotation device includes a pair of chucks for clamping said interior subassembly.
18. The apparatus according to claim 17, wherein said mounting mechanism includes a lateral translation mechanism for laterally translating the chucks during rotation thereof, thereby laterally translating the interior subassembly during rotation.
19. The apparatus according to claim 11, comprising a feeder mechanism for feeding said interior subassembly into said mounting mechanism.
Type: Application
Filed: May 26, 2006
Publication Date: Nov 29, 2007
Applicant:
Inventors: Andrew Karl Tsekrekos (Hamilton), John Esposito (Burford), Stanislaw John Pasek (Brantford), Douglas DeVouge (Brantford)
Application Number: 11/441,853
International Classification: B21D 51/16 (20060101);