Patent Application
20200208562
This application is a U.S. non-provisional application claiming the benefit of French Application No. 18 74255, filed on Dec. 27, 2018, which is incorporated herein by its entirety.
The invention relates in general to the manufacture of exhaust components with thin walls.
More specifically, according to a first aspect, the invention relates to a machine for manufacturing an exhaust component having a body including a tubular enclosure, the tubular enclosure having an enclosure thickness of less than 0.9 mm. The exhaust component also includes a cover, having a cover thickness of less than 1.2 mm.
The fastening of the cover on the body is particularly delicate. The cover must be mounted on the body while guaranteeing an excellent alignment between the two parts. Furthermore, to allow the welding of these two parts to one another, it is necessary for the gap between the edge of the cover and the end of the tubular enclosure to be reduced, over the entire perimeter of the tubular enclosure.
In this context, the invention seeks to propose a manufacturing machine making it possible to meet the above requirements.
A machine for manufacturing an exhaust component comprising:
the machine comprising:
The manufacturing machine thus makes it possible to fit the first end of the tubular enclosure in the tubular edge of the cover. The converging passage of the fitting tool is particularly well suited to such an operation.
An assembly by fitting is particularly well suited due to the fact that the tubular enclosure and the cover have reduced wall thicknesses, which gives them great flexibility.
When the first end perimeter and the edge perimeter verify the criterion stated in claim 1, it is possible to obtain an extremely reduced gap between the first end and the tubular edge, after fitting of the first end in the tubular edge. In particular, the first end of the tubular enclosure deforms resiliently when it passes through the fitting tool, which contributes to obtaining the smaller gap.
The pre-positioning tool of the body, and the use of a fitting tool, make it possible to obtain an extremely precise alignment of the tool with the cover. Placing the cover in a receiving seat also contributes to obtaining this result.
The machine may also have one or more of the features below, considered individually or according to any technical possible combination(s):
According to a second aspect, the invention relates to a method for manufacturing an exhaust component, the method comprising the following steps:
The method further comprising the following steps:
Other features and advantages of the invention will emerge from the detailed description thereof provided below, for information and non-limitingly, in reference to the appended figures, in which:
The machine and the method according to the invention seek to manufacture an exhaust component that is, for example, of the type shown in
This exhaust component 1 is an exhaust gas purification device.
In a variant, the exhaust component is a muffler or any other element of a vehicle exhaust line.
This exhaust component is provided to be integrated into a vehicle exhaust line, in particular a vehicle with a heat engine.
This vehicle is typically a motor vehicle, for example a car, a bus, or a truck.
The component 1 includes a tubular segment 3, a cover 5, and typically another cover 6.
The tubular segment 3 includes a tubular enclosure 7.
The tubular enclosure 7 has a first end 9, having a first end perimeter, and a first central end axis X1.
The first central axis X1 is generally combined with the central axis X of the exhaust component, shown in
The cover 5 has a central wall 11, extending by a tubular edge 13. The cover 5, in particular the tubular edge 13, has a cover thickness smaller than 1.2 mm, typically in the order of 1 mm.
The tubular edge 13 has an edge perimeter comprised between the end perimeter and the end perimeter minus 2 mm. The tubular edge 13 has a central edge axis XB.
In the case where the volume 1 is a purification device, the tubular segment 3 includes an exhaust gas purification member 15, housed in the tubular enclosure 7. A maintaining web 17 is inserted radially between the purification member 15 and the tubular enclosure 7. The purification member is of any suitable type.
For example, it is a three-way catalyst, or an oxidation catalyst of the nitrogen oxides, or a particle filter, or any other type of exhaust gas purification member.
The tubular enclosure 7 has, perpendicular to the axis X, circular sections.
In a variant, these sections are oval, or any other suitable shape.
The tubular enclosure 7 has a central segment 19 extending axially by the first end 9 on one side and by a second end 21 on the other side. Perpendicular to the axis X, the first and second ends 9, 21 have sections relatively larger than the central segment 19.
The tubular enclosure 7 has an enclosure thickness smaller than 0.9 mm, preferably in the order of 0.8 mm.
In particular, the first end 9 and/or the second end 21 have an enclosure thickness smaller than 0.9 mm, preferably in the order of 0.8 mm.
The tubular edge 13 has a section with a shape corresponding to that of the first end 9. Thus, if the first end 9 is circular, the tubular edge 13 will also have a circular section perpendicular to the central edge axis XB.
The cover 5 has an orifice 23, formed in the central wall 11. The orifice 23 is, depending on the case, provided to constitute either an exhaust gas inlet into the component 1, or an exhaust gas outlet outside the exhaust component 1.
The manufacturing machine, in one example, is provided to assemble the body including at least the tubular segment 3 (
The manufacturing machine 25, shown in
The manufacturing machine 26, shown in
The manufacturing machine 25 will first be described.
The machine 25 comprises a seat 31 for receiving the cover 5 in a determined cover position in which the central edge axis XB is substantially aligned with a main axis XP of the machine.
The seat 31 in particular includes three cams, the positions of which are precisely controlled so as to position the cover 5 in the determined cover position.
In this position, the central wall 11 is typically turned downward, and the tubular edge 13 is typically turned upward.
In the cover position, the axis X0 passing through the center of the orifice 23 is located in a known and predetermined orientation. In particular, the axis X0 in this position forms a predetermined angle with the central axis XP of the machine, and occupies a predetermined circumferential position around the main axis XP.
The machine 25 further includes a tool 33 for pre-positioning of the body.
The tool 33 is configured to pre-position the body relative to the cover 5 in a starting position in which the first central end axis X1 forms, with the central edge axis XB, an angle smaller than 20°.
Preferably, this angle is smaller than 10°, and still more preferably, this angle is smaller than 5°.
The machine 25 further includes a fitting tool 35, inserted between the receiving seat 31 and the pre-positioning tool 33 along the main axis XP.
As shown in particular in
The large opening 39 has a larger section than the first end, and the small opening 41 has a smaller section than the tubular edge 13.
The machine 25 further includes an actuator device 42, configured to push the body along the main axis XP toward the cover 5 through the converging passage 37.
This method allows the first end 9 of the tubular enclosure to pass through the passage 37 and to be fitted in the tubular edge 13.
The converging passage 37 is configured to deform the first end 9 of the tubular enclosure 7 while the latter passes through the passage 37.
As shown in particular in
The sectors 43 typically move between their radially inner position and their radially outer position according to respective movements having a radial component with respect to the main axis of the machine.
This movement is symbolized by the arrows F in
In
The passage 37 has straight sections, perpendicular to the main axis XP, which become narrower from the large opening 39 to the small opening 41.
These sections have a shape corresponding to that of the first end 9. Typically, they are circular, the passage 37 therefore having a frustoconical shape, coaxial to the axis XP.
The pre-positioning tool 33 includes an inner passage 45 (
The inner passage 45 is provided to receive the first end 9 in the starting position, and cooperates with said first end so as to keep the tubular enclosure 7 in the starting position.
Thus, if the first end 9 has a circular section, the inner passage 45 will be substantially cylindrical, with a diameter slightly larger than the outer diameter of the first end 9.
The inner passage 45 is substantially coaxial to the central axis XP.
The inner passage 45 typically has a section identical to that of the large opening 39.
Advantageously, the sectors 43 in the radially inner position also define the pre-positioning tool 33.
Thus, as shown in
The free surfaces 49, in the radially inner position, also delimit a cylindrical passage 51, extending the converging passage 37 along the main axis XP toward the seat 31. This cylindrical passage 51 has an inner section substantially identical to that of the small opening 41. The cylindrical passage 51 makes it possible to reduce the pressure and wear of the surface of the converging passage 37.
Typically, the fitting tool 35 comprises a wider passage 53, extending the converging passage 37 toward the seat 31 along the main axis XP.
The wider passage 53 has a larger section than that of the small opening 41.
Typically, these are the sectors 43 which, in the radially inner position, form the wider passage 53. The wider passage has a cylindrical shape, coaxial to the main axis XP, for example with a circular section perpendicular to the main axis XP.
In the present case, the cylindrical passage 51 is interposed between the converging passage 37 and the wider passage 53.
The inner surface of the wider passage 53 connects to the inner surface of the intermediate passage 51 by a reentrant shoulder 55.
Advantageously, the free edge 57 of the tubular edge 13 is received in the wider passage 53 in the cover position.
As shown in
The tubular edge 13 is completely housed in the annular volume located in the extension of the shoulder. In other words, the free edge 57 does not, at any point of its periphery, protrude radially inward relative to the shoulder 55. It thus cannot create interferences when the first end 9 is pushed to the inside of the tubular edge 13, through the converging passage, then through the intermediate passage 51.
According to variants that are not shown, the pre-positioning tool and/or the wider passage are not formed by the sectors 43. The prepositioning tool and/or the wider passage in this case are formed by independent parts of the sectors 43, which may or may not be radially movable.
Advantageously, the machine 25 includes a reversible locking 59, configured to selectively block the cover 5 relative to the seat 31 in its cover position.
Such a locking makes it possible to keep the cover 5 in position in particular during the fitting of the first end 9.
Preferably, this reversible locking 59 is done by the sectors 43. For example, the sectors 43 move from their radially outer position to their radially inner position according to a movement that is both radial and parallel to the main axis XP. In their radially inner position, they exert a pressure on the cover 5, blocking the latter in position. For example, the free edge 57 bears axially on the shoulder 55, and radially against the inner surface of the wider passage 53.
In a variant, the reversible locking 59 is independent of the sectors 43.
Preferably, the machine 25 comprises at least one adjustable stop 61 of the actuator device 42. In the illustrated example, the machine 25 includes two adjustable stops 61. The at least one adjustable stop 61 is arranged so as to adjust the separation along the main axis XP between a reference point of the cover 5 and a reference point of the body.
In other words, the at least one stop 61 adjusts the height over which the first end 9 is inserted into the tubular edge 13, while stopping the movement of the body.
The actuator device 42 comprises a guide head 63 arranged to push the body, an actuator 65 configured to move the guide head 63 in its movement along the main axis XP, and a linear guide 67 guiding the guide head 63 along the main axis XP.
The guide head 63 is provided to bear on the second end 21 of the tubular enclosure 7.
Advantageously, it comprises a shape 69 provided to receive, inwardly, said second end 21.
This shape 69 guarantees the alignment of the tubular enclosure 7 with the cover 5.
Indeed, the shape 69 is provided to center the second end 21 of the tubular enclosure relative to the main axis XP, the first end 9 being centered by the pre-positioning tool 33.
One thus obtains a strict alignment of the central axis X of the tubular enclosure on the main axis XP. The cover 5 in turn is aligned with the main axis XP by the seat 31.
The shape 69 is a hollow shape, having a bottom 71 surrounded by a diverging edge 73 flaring from the bottom 71. The bottom 71 has a section substantially identical to that of the second edge 21.
The linear guiding 67 includes one or several columns 74, oriented along the main axis XP.
The guide head 63 includes a plate 75 having orifices in which the columns 74 are engaged freely sliding.
The shape 69 is fastened on the plate 75.
The manufacturing machine 26 of
As indicated above, it is provided to receive a body formed by the cover 5 disclosed above and the tubular segment 3, the first end 9 of the tubular enclosure 7 already being fitted in the tubular edge 13 of the cover 5. The fillet formed by the tubular enclosure 7 and the cover 5 is welded, which prevents the assembly from becoming unfitted. This body is shown in
The machine of
The second end 21 has a second end perimeter, and a second central end axis X2.
The other cover 6 is of the same type as that shown in
The other cover has another central wall 81 extending by another tubular edge 83. The other tubular edge 83 has another edge perimeter comprised between the second end perimeter and the second end perimeter minus 2 mm. It has another central edge axis XB′. It has another orifice 84, the latter typically being either the exhaust gas outlet outside the exhaust component or the exhaust gas inlet to the inside of the exhaust component.
Only the differences between the machine 26 of
Elements that are identical or perform the same function in both machines will be designated using the same references.
In the machine 26, shown in
The at least one cam member 85 is provided to cooperate with a cam follower 87 formed on the body to place said body along a predetermined orientation around the main axis XP relative to the other cover 6.
The cam member(s) 85 are, for example, orientation fingers along the main axis XP. The cam follower is for example a hollow relief 87, formed on the central wall 81 of the other cover.
The guide head 63 does not include the hollow shape 69 shown in
The cam member 85 and the cam follower(s) 87 in particular make it possible to orient the orifice 84 correctly relative to the orifice 23, in particular around the main direction XP.
The method for manufacturing the exhaust component 1 will now be described.
This manufacturing method is typically provided to be implemented by first using the manufacturing machine 25 illustrated in
The manufacturing method comprises the following steps:
The tubular segment 3 is of the type described above and illustrated in
The cover 5 is of the type described above and illustrated in
Before the pre-positioning and introduction steps, the cover 5 is preferably introduced into a seat 31 and placed in a determined cover position. In this position, the central edge axis XB is substantially aligned with the main axis XP.
Preferably, the cover 5 is locked in its cover position, by any suitable method, in particular those disclosed in reference to the machine 25.
As disclosed above, this can be done by the sectors 43, these sectors in the radially inner position reversibly locking the cover 5 in its cover position. In a variant, it is a specific mechanism that locks the cover in its cover position.
The pre-positioning of the tubular segment 3 is typically done with the pre-positioning tool 33 disclosed above.
The pre-positioning of the tubular segment 3 is done by introducing the first end 9 of the tubular enclosure 7 into the pre-positioning tool 33. More specifically, as illustrated in
The converging passage 37 is typically as described above.
The pre-positioning and the introduction are typically done by using the sectors 43 described above, these sectors making it possible, due to the presence of the wider passage 53 and the shoulder 55, to guarantee the absence of interference between the first end 9 of the tubular enclosure and the tubular edge 13 during the fitting of the first end 9.
The tubular segment 3 is moved toward the cover 5 as described above.
More specifically, an actuator device 42 belonging to the machine 25 pushes the tubular segment 3 along the main axis XP toward the cover 5. The guide head 63 of the actuator device 42 cooperates with the second end 21 of the tubular enclosure 7.
More specifically, this guide head 63 is configured to guarantee the alignment of the tubular enclosure 7 with the cover 5. In other words, it guides the tubular enclosure 7 such that the central axis X of the tubular enclosure 7 is aligned with the central edge axis XB.
This is obtained as described hereinabove, by the use of a hollow shape 69, inwardly receiving the second end 21 of the tubular enclosure 7. The shape 69 includes a flat bottom 71 and a diverging edge 73 surrounding the flat bottom 71. During the movement of the guide head 63 along the main direction toward the cover 5, the second end 21 of the tubular enclosure 7 engages in the shape 69. The diverging edge 73 guides the second end 21 in a plane perpendicular to the central axis XP, to shim this second end 21 against the bottom 71 and to center the second end 21 on the axis XP.
The actuator 65 pushes the guide head 63. The movement of the guide head is strictly along the main axis XP, due to the fact that the guide head 63 is guided in translation by the columns 74.
During the introduction step of the first end 9, this first end travels the converging passage 37. The section of the small opening 41 is slightly smaller than the section of the tubular edge 13. The first end 9 is therefore deformed during its passage through the converging passage 37, but this deformation remains in the elastic domain due to the fact that the tubular enclosure 7 has a reduced thickness, and due to the fact that the difference between the first end perimeter and the edge perimeter is reduced.
After the step for introducing the first end into the tubular edge, the subassembly 89 formed by the tubular segment 7 and the cover 5 fastened to this tubular segment is discharged from the machine 25.
To that end, the sectors 43 are brought back into their radially outer position. This eliminates the stress applied to the first end 9 of the tubular enclosure, which can relax and expand radially. This radial expansion allows the first end 9 to be pressed against the tubular edge 13, over its entire periphery, with a very small separation between the first end and the tubular edge, typically less than 0.2 mm over the entire periphery of the tubular edge 13.
Advantageously, the method comprises, after the discharge from the subassembly 89, a step during which the tubular edge 13 is welded on the first end 9 by a MAG method, and preferably by a MAG method with low energy.
In the MAG method, a wire is continuously added at the weld. In a low-energy MAG method, the wire is added discontinuously. The arc is suppressed when a drop is deposited with the aim of reducing projections.
Due to the very small separation between the tubular edge 13 and the first end 9, the welding of the tubular edge on the first end using the MAG or low-energy MAG method is done under excellent conditions.
The method further preferably includes the following steps:
These steps are done with the machine 26, shown in
The pre-positioning step is done by first introducing the other cover 6 into the seat 31 of the machine 26, and locking the latter in position relative to the seat 31 in its cover position. This is typically done like on the machine 25, and as described above relative to the cover 5.
For the pre-positioning, the second edge 21 is typically engaged inside the inner passage 45.
The introduction of the second end 21 into the other tubular edge 83 is done as described above by pushing the second end 21 through the converging passage 37.
In the same manner as before, due to the small thickness of the tubular enclosure 7, and due to the small difference between the second end perimeter and the other edge perimeter, the second end 21 experiences a resilient deformation during its passage through the converging passage 37.
Once the sectors 43 are brought back into their radially outer position, the second end 21 relaxes resiliently and places itself against the other tubular edge 83 over its entire periphery.
The method advantageously includes a step for welding the other tubular edge 83 on the second end 21, by a MAG or low-energy MAG method.
Because there is only a small gap between the second end and the other tubular edge, typically smaller than 0.2 mm over the entire perimeter of the other tubular edge, this welding is done under excellent conditions.
Typically, the method comprises a step for orienting the cover 5 relative to the other cover 6 around the main axis XP, before the step for introducing the second end 21.
This is typically done as described above. The cam member(s) 85 of the guide head 63 cooperate with the cam follower(s) 87 formed on the cover 5. This makes it possible to give the subassembly 89 a predetermined orientation relative to the other cover 6.
When the exhaust component 1 includes an exhaust gas purification member, it is particularly important to control the position well of the inlet face 91 of the purification member 15 relative to the inlet orifice of the exhaust gases to the inside of the exhaust component 1.
The method according to the invention makes it possible to control this parameter particularly precisely.
Two approaches are possible, respectively illustrated in
According to the first approach, illustrated in
In this case, the orifice 84 of the other cover 6 corresponds to the exhaust gas outlet outside the exhaust volume 1.
As indicated above, the cover 5 is first assembled to the tubular enclosure 7, the other cover 6 being assembled second.
During the assembly phase of the cover 5, the movement of the tubular segment 3 toward the cover 5 is stopped by a stop 61 arranged so that the second end 21 of the tubular enclosure 7 has a predetermined separation along the main axis XP relative to a reference point 93 of the cover when the stop 61 is reached.
The stop 61 is as described above relative to the machine 25. The movement of the tubular segment 3 is stopped when the plate 75 of the guide head 63 seeks to bear against the stops 61.
The reference point 93 of the cover 5 is, for example, a planar surface of the central wall 11.
Thus, the stops 61 of the machine 23 are adjusted such that the separation between the reference point 93 and the second end 21 corresponds to a predetermined value L1. Furthermore, during the method for manufacturing the tubular segment 3, the position of the inlet face 91 of the purification member 15 is adjusted such that it has a predetermined separation L2 relative to the second end 21 of the tubular enclosure 7, along the central axis X of said tubular enclosure 7.
The separation L3 along the central axis of the tubular enclosure 7 between the reference point 93 and the inlet face 91 is equal to L1−L2.
By adjusting the position of the stops 61 along the main axis of the machine, it is thus possible to adjust the value of L1, and therefore to control the value of L3.
The second approach is illustrated in
In this second approach, the orifice 23 of the cover 5 corresponds to an exhaust gas outlet outside the exhaust component 1. The orifice 84 of the other cover 6 is therefore an exhaust gas inlet to the inside of the exhaust component.
During the step for introducing the first end 9, the movement of the tubular segment 7 toward the cover 5 is stopped by a stop 61 arranged so that the second end 21 of the tubular enclosure 7 has a predetermined separation L4 along the main axis XP relative to a reference point 95 of the cover 5 when the stop 61 is reached.
This reference point 95 is preferably the same as the reference point 93.
During the step for introducing the second end 21, the movement of the subassembly 89 toward the other cover 6 is stopped by a stop 61 arranged so that the reference point 95 of the cover has a predetermined separation along the main axis relative to another reference point 97 of the other cover 6 when the stop 61 is reached.
During the manufacturing of the tubular segment 3, the inlet face 91 of the purification member 15 is shimmed with a predetermined separation L6 with respect to the second end 21 of the tubular enclosure, along the central axis X of this tubular enclosure 7.
In the machines 25 and 26, the central axis of the tubular enclosure is aligned with the main axis XP, XP′ of the machine.
The separation L7 between the inlet face 91 of the purification member 15 and the reference point 97 of the other cover 6, bearing the inlet of the exhaust component, is equal to L6+L5−L4.
The stops 61 of the machines 25 and 26 thus make it possible to shim the lengths L4 and L5 such that the separation L7 is in the predetermined desired range.
The method of the invention also allows precise control of other characteristics of the exhaust component.
According to one advantageous aspect of the invention, it makes it possible to ensure that the overlap length between the first end 9 of the tubular enclosure 7 and the tubular edge 13 is in a predetermined range.
The tubular enclosure 7 has, along the first central end axis, a length equal to a nominal length L0, plus an allowance comprised in an interval [−ΔL1+ΔL2].
For example, ΔL1 and ΔL2 are both equal to 3.3 mm.
The stop 61 is configured to stop the movement of the tubular segment 3 toward the cover 5 such that a tubular enclosure 7 of nominal length L0 has its first end engaged in the tubular edge 13 over a predetermined covering length R when the stop 61 is reached.
The predetermined covering length R is chosen such that R−ΔL1 is comprised in the interval [2 mm, 5 mm].
For example, the predetermined covering length R is 6.7 mm R−L1 corresponds to the minimum overlap, that is to say, the overlap obtained when the tubular enclosure has its minimum length in light of the allowances. In this numerical example, R−ΔL1 is equal to 6.7-3.3=3.4 mm.
Advantageously, the tubular edge 13 has a predetermined height H0 along the first determined central axis, chosen such that R+ΔL2<H0.
In other words, the predetermined height H0 is chosen to avoid any interference between the first end 9 and the central wall 11 of the cover 5 in the case where the tubular enclosure 7 is of maximum length in light of the allowance.
Additionally, as explained above, the tubular enclosure 7 has a step 99 between its central segment 19 of relatively smaller section and the first and second ends 9, 21, of relatively larger sections.
In order to avoid the formation of cracks at this step 99, during welding, a minimum distance between the weld bead and the step must be respected. Typically, this minimum separation is between 3 and 7 mm, and is for example equal to 5 mm.
This constraint is taken into account when choosing the length L of the first end 9 along the first central end axis X1 up to the step 99.
The length L of this first end is chosen in the interval R+ΔL2+3 mm, R+ΔL2+7 mm.
Above, it has been described how the method according to the invention makes it possible to satisfy geometric constraints relative to the first end 9 of the tubular enclosure 7 and the tubular edge 13 of the cover 5.
The method of the invention makes it possible to satisfy the same geometric constraints relative to the second end 21 and the other tubular edge 83 of the other cover 26. These constraints are satisfied by using the same approach.
It has been described here that the machine 25 makes it possible to fasten the cover 5 on the tubular segment 3 and the machine 26 fastens the other cover 6 on the tubular segment 3. In a variant, the machine 25 fastens the other cover 6 and the machine 26 fastens the cover 5.
Likewise, the machine 25 has been described as fastening the cover 5 on the first end 9 of the tubular enclosure 7. In a variant, the machine 25 fastens the cover 5 on the second end 21 of the tubular enclosure 7. In this case, the machine 26 fastens the other cover 6 on the first end 9 of the tubular enclosure 7.
Although an embodiment has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this disclosure. For that reason, the following claims should be studied to determine the true scope and content of this disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 18 74255 | Dec 2018 | FR | national |
