Method for manufacturing an exhaust system and exhaust system

Abstract

An exhaust system is manufactured in the following manner. Initially, a plurality of pipe sections are put into each other with a clearance fit, so that connecting points are formed, at which two pipe sections overlap each other. The pipe sections then are calibrated at the connecting points, so that a narrow gap is obtained. Subsequently, the connecting points are soldered. The exhaust system thus includes a plurality of pipe sections which are put into each other and soldered to each other. Outer pipe sections of the plurality of pipe sections are calibrated.

Claims

1. A method for manufacturing an exhaust system including a plurality of pipe sections, comprising the following steps: selecting more than ten different pipe sections from a given construction set of pre-produced pipe sections as the plurality of pipe sections; putting the entire exhaust system together by putting each of the plurality of pipe sections into another respective pipe section with a clearance fit, so that connecting points are formed at which two pipe sections overlap each other; calibrating the pipe sections at all connecting points at the same time by applying a pressure onto an outer pipe of the two pipe sections in a radial inward direction so that at least the outer pipe of each connecting point is deformed plastically and a narrow gap is obtained between the overlapping pipes; and soldering all of the connecting points of the entire exhaust system at the same time.

2. The method according to claim 1, wherein the exhaust system is soldered in a horizontal orientation.

3. The method according to claim 1, wherein before putting the pipe sections together, a solder material has been applied at one end of a pipe section.

4. The method according to claim 1, including associating a holding device with each connecting point, wherein the holding device suitably fixes the pipe sections.

5. The method according to claim 4, including using pressing jaws associated with the holding device to apply the pressure in a radially inward direction about the outer circumference of the outer pipe of the two pipe sections.

6. The method according to claim 5, wherein the pressing jaws are integrated into the holding device.

7. The method according to claim 5, including arranging solder material in a region of each connecting point, and simultaneously heating each connecting point such that the solder material melts and after cooling reliably connects the two pipe sections with each other.

8. The method according to claim 7, including using an induction device to heat the solder, wherein the induction device is integrated into the holding device.

9. The method according to claim 7, including using an induction device to heat the solder, wherein the induction device and pressing jaws are integrated into the holding device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be described below with reference to the attached drawings, in which:

(2) FIG. 1 schematically shows an exhaust system during the manufacture;

(3) FIG. 2 schematically shows a section through the exhaust system at a connecting point which is accommodated in a holding device;

(4) FIG. 3 schematically shows the detail III of FIG. 1;

(5) FIG. 4 schematically shows a section through a connecting point during calibrating; and

(6) FIG. 5 schematically shows a section through a connecting point during soldering.

DETAILED DESCRIPTION

(7) FIG. 1 schematically shows an exhaust system 10, which contains a connecting flange 12, several pipe elbows 14, several pipe sections 16, several coupling sleeves 18 as well as a catalyst housing 20, and a muffler 22. The pipe sections 16, as well as the pipe elbows 14 and the coupling sleeves 18, which here also are regarded as pipe sections, are prefabricated parts of a modular system from which those parts are selected for the respective type of vehicle, with which the desired pipe route, the desired dimensions, etc. can be obtained. All pipe sections are made of sheet metal, wherein wall thicknesses in the range down to 0.6 mm are possible.

(8) The pipe sections are put into each other, so that a multitude of connecting points 30 is formed (see also FIGS. 2 and 3). All pipe sections are dimensioned such that they can be put into each other with a clearance fit. This provides for premounting the entire exhaust system with little effort on an assembling table 40, wherein a holding device 42 is associated with each connecting point. In the first step, the function of the holding device 42 includes suitably fixing the pipe sections.

(9) As shown in FIG. 4, a comparatively large clearance S exists in the region of a connecting point 30 (shown here by way of example for a connecting point between a coupling sleeve 18 and a pipe section 16), when the exhaust system is loosely put together, i.e. in the premounted condition. This clearance S provides for easily putting the pipe sections into each other, without the individual components getting jammed or larger forces having to be applied.

(10) To fasten the individual pipe sections to each other in the region of the corresponding connecting points 30, the corresponding connecting point 30 initially is calibrated. This is shown schematically in FIG. 4, in which several pressing jaws 44 are shown, which exert a pressure acting radially to the inside on the outer pipe section, here the coupling sleeve 18, and hence indirectly also on the inner pipe section. The applied force is so high that at least the outer pipe section is plastically deformed, i.e. has a smaller inside diameter after calibrating than before. This ensures that after calibrating a comparatively narrow gap (see the smaller gap S in FIG. 5) is present, which provides for reliably soldering the pipe sections to each other.

(11) The pressing jaws 44 can be mounted at the holding device or be integrated into the same. For example, a pair of calibration tongs can be associated to each holding device, which closes around the connecting point 30 and there applies the necessary pressure.

(12) For the purpose of soldering, a solder ring of a solder material, in particular high-temperature solder material, can be arranged in the region of the connecting point. Alternatively or preferably, it is provided that in the region of the connecting point at least one of the pipe sections is coated with a solder material, in particular with a printed or similarly applied solder paste (see the solder material 28 schematically indicated in FIGS. 2 and 3). For soldering the pipe sections it then is provided that after calibrating, the connecting point 30 is heated, in particular by an induction device 46 (see FIG. 5) with which the connecting point 30 can be heated such that the solder material melts and after cooling reliably connects the two pipe sections with each other.

(13) The induction device 46 also is preferably integrated into the holding device 42, so that after clamping the exhaust system on the assembling table 40, first the calibrating step and then the soldering step can be performed automatically, while the exhaust system remains fixed on the assembling table.

(14) With regard to the productivity it is particularly advantageous that the entire exhaust system can be premounted horizontally, and in addition all connecting points can be soldered at the same time. It has no influence that depending on the concrete type of the exhaust system a very high number of connecting points 30 is present, in particular ten or more connecting points.

(15) Although an embodiment of this invention 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.