EP2373920B1 - Compressed air tank for utility vehicles and method of manufacture - Google Patents

Description

The invention relates to a compressed air tank for commercial vehicles according to the preamble of claim 1.

The invention further relates to a method for producing compressed air tanks according to the preamble of claim 10 and to an apparatus for carrying out the method.

Compressed air containers for commercial vehicles are known from the general state of the art and are used for various functionalities, in particular for compressed air supply of air suspensions of commercial vehicles.

Compressed air tanks can be used in commercial vehicles to supply a variety of consumers. In addition to compressed-air brake systems and air suspensions, these may also be rescue systems (for example airbags) or systems that change the tire pressure of commercial vehicles. However, pressure vessels are not only used in commercial vehicles and passenger cars, but also in other vehicles, e.g. used in rail vehicles.

A pressure vessel for supplying vehicles, in particular commercial vehicles, with a pressurized gaseous medium is, for example, from the closest prior art DE 20 2005 018 579 U1 known.

Conventional pressure vessels have a tubular or cylindrical peripheral wall (shell), the open end faces with corresponding covers (outer bottoms) closed, in Normally welded, be. This creates a cavity for storing the intended gas. The cavity can be loaded and / or unloaded via connections (holes) in the jacket or the exterior floors.

The DE 20 2005 018 579 U1 describes an advantageous embodiment of a compressed air tank such that at least one outer bottom is formed integrally with the jacket. Optionally, both outer floors may be formed integrally with each part of the peripheral wall.

In general, compressed air cylinders must withstand mechanical stresses due to internal or external pressure as well as other mechanical, physical (temperature) and chemical loads. A common material for the production of appropriate pressure vessels is steel. Steel containers basically have the advantage of a high mechanical strength and thus a high pressure resistance and also a good temperature resistance. In contrast, the chemical resistance of steel to corrosive substances is rather poor. Steel containers are also relatively susceptible to external weather influences, so that as a rule an additional external and possibly inner coating or coating is provided. The inner coating of a compressed air tank is achieved in the prior art by a so-called. Wet coating, which, however, does not lead to satisfactory results and in particular can not be applied inexpensively. In addition, there is the problem in the known compressed air tanks that at the junction between the outer bottom and the peripheral wall (sheath) a so-called. Schmutzkante (also referred to as chemical edge) is formed. Adhere to this particle or general impurities, which then interfere with the application of an inner coating or make impossible. The dirt edge, which arises when the outer floor is connected to the jacket, can be, for example, the FIG. 6 of the DE 20 2005 018 579 U1 remove. The outer bottom generally has an inwardly tapering bead (Einführschräg), over which the shell or the peripheral wall is pushed. As a result, a contact region is created, which is then subsequently welded by MAG welding in such a way that the outer bottom is connected to the jacket.

In the known from the prior art compressed air tanks in which both outer floors are formed independently of the jacket, therefore, arise two such dirty edges. The embodiment according to the FIG. 1 of the DE 20 2005 018 579 U1 Although avoids such dirty edges, but requires a greater effort to produce the sleeves.

A disadvantage of the MAG welding method for connecting the outside ground to the shell is that the MAG welding process is relatively slow.

Another problem with the known from the prior art compressed air tanks is the attachment of sleeves on or around the holes in the outer floors or in the jacket. The holes serve various purposes, such as the connection of lines. Such degrees are, for example, the FIG. 1 of the DE 200 23 422 U1 to see which shows a compressed air tank made of plastic. In an embodiment of a pressure vessel made of metal, provision is generally made for welding sleeves onto the bores in the outer bottom or the jacket. The welding of the sleeves is in turn carried out via a MAG welding process. The disadvantage here is that the welding of the sleeve causes a lot of effort, especially because the MAG welding process is relatively slow and also welding material is necessary.

The present invention has for its object to solve the disadvantages of the prior art, in particular to provide a compressed air tank for commercial vehicles, which is inexpensive and easy to manufacture.

The present invention is also based on the object to provide an advantageous method for producing a compressed air tank and to provide an apparatus for performing the method.

This object is achieved with respect to a to be created compressed air tank by claim 1.

An advantageous method for producing a compressed air tank results from claim 10.

An advantageous device for carrying out the method results from claim. 13th

The fact that the contact surfaces between the shell and the outer floors are designed such that the contact surfaces abut against each other butt and a connection without welding material by laser welding, a compressed air tank without the usual dirt or chemical edge is created. That the previously existing, inwardly tapering supernatant or the bead on the outer floors over which the jacket is pushed in preparation for a welded connection, is eliminated. by the solution provided according to the invention.

The inventive solution results in the inside of the container, a surface which is optimally suitable for painting and coating, since projections and recesses (Sehmutzkanten or chemical edges) are avoided. This results in a high quality for the paint or the coating. In addition, will avoided that residues accumulate on the inner edges, which migrate through the lines during operation and possibly cause problems in brake lines or the like.

The outer floors can be quickly and reliably connected to the shell by an orbital circumferential weld produced by laser welding. In order to enable the use of a laser, the respective contact surfaces are processed in such a way that the contact surfaces to be connected can be set against one another in a flat or blunt or in a custom-made manner. The resulting between the contact surfaces gap should be as low as possible, i. the contact surfaces are machined so precisely that the resulting gap is small, i. suitable for laser welding is.

To produce an optimum weld seam, it may be advantageous to align the laser in such a way that the laser beam impinges on the gap between the two contact surfaces in a manner free of light gaps.

In an embodiment of the invention it can be provided that the mutually aligned contact surfaces have a skew of up to 45 °, preferably 15 ° +/- 5 °. The aligned contact surfaces may preferably have an identical skew. The skewing results in the self-centering of the two components when attaching the outer bottom to the front side of the shell. The bevel can be designed so that a kind of dovetail connection results between the two components to be connected.

The skewing can be designed both from the inside to the outside sloping and rising, in both cases results a self-centering of the components also a light gap is avoided.

The disadvantage of skewing is that it causes additional manufacturing effort. Therefore, it is preferably provided that the contact surfaces have no skew. Ie. the contact surfaces extend or lie in a radial plane of the compressed air tank or extend in a plane which is perpendicular to the axis of the pressure vessel.

It is advantageous if the laser is also used in addition to the welding of the outer floors with the end faces of the shell to provide the jacket (after bending) with a longitudinal weld.

It is advantageous if two laser heads are used to produce the orbital weld seam for connecting an outer floor to the jacket, which simultaneously weld the contact surface between the outer floor and the jacket. This results in a further speed advantage.

All welded joints for the manufacture of the compressed air tank, i. e.g. the longitudinal weld and the two orbital welds can be created by means of the laser without welding material. An advantage is that no oxide layer is formed in this case, because the component is only lukewarm.

According to the invention it is further provided that the sleeve is welded by laser welding or CD welding to the bore.

This allows a much faster welding of the sleeve than in the prior art. An addition of welding material is no longer necessary.

Another advantage of laser welding is that the regularly negative welding seam bulge resulting from MAG welding is avoided. In addition, a cleaning of the weld during laser welding is not required, so that this can be omitted in a MAG weld frequently necessary operation.

Compressed air tanks generally have a plurality of holes provided with sockets, which are arranged in one or both outer floors and / or on the jacket. It is advantageous if the inner diameter of the bore is slightly larger than the inner diameter of the sleeve. The sleeve may be formed in a known manner, preferably with an internal thread. The sleeve is preferably made of steel or stainless steel.

The holes or the holes in the outer bottom can be made, for example, by punch or by punching.

It is advantageous if the laser welded to the sleeve radially outward circumferentially with the compressed air tank.

In one embodiment, it may be provided that the sleeve has a recess, a bevel, a (preferably wedge-shaped) groove or the like, which is arranged such that between this and the compressed air tank remain a ridge formed by the sleeve, an annular projection or the like , It can be provided that the laser beam of a laser applied from the outside penetrates into the groove, the chamfer or the groove such that the burr or the annular projection of the sleeve is welded to the adjacent material of the compressed air tank, thus the sleeve can be particularly process reliable , fast and extremely strong welding with the compressed air tank. It is also advantageous if the welding of the sleeve with the compressed air tank radially outward and circumferentially takes place at the bottom of the sleeve. As a result, there is no gap between the sleeve and the compressed-air reservoir into which any impurities may penetrate.

The welding of the sleeve by an externally attached laser is suitable both for welding the sleeve to the outer floors and to the jacket.

Alternatively or additionally, it can also be provided that the laser, in particular in order to weld sleeves onto boreholes of the outer bottom, is applied from the inside. Preferably, the laser can weld as far as possible radially outward annular surface of the sleeve with the compressed air tank. This in turn avoids a radially circumferential gap between the sleeve and the compressed air tank.

The Verschmelzkante should preferably be radially as far outside as possible.

An advantage of welding the sleeve in that the laser is applied to the inside of an outer bottom, is that the sleeve merges particularly advantageous with the material of the compressed air tank. The welding process, as the inventor has found out, can be controlled in a particularly process-reliable manner. The method is particularly suitable for attaching sleeves on the outer floor, since in this case the laser can be particularly easily applied to the inside of the outer floor. The sleeves can preferably be welded to the outer bottom before the outer bottom is welded to the jacket, since the jacket can not be welded with the laser.

Another way to weld the sleeve on or around the bore of the compressed air tank is to use a so-called CD welding method. CD Welding means Capacitor Discharge or Capacitor Discharge Welding. CD welding is a special form of projection welding and, as the inventors have found, has particular advantages in connecting sleeves to compressed air tanks. By a corresponding grounding of the compressed air tank can take place after the attachment of the sleeve by a corresponding surge within a few milliseconds a permanent and reliable welding of the sleeve at the intended location of the compressed air tank. The sleeve can, for example, be attached to the intended location of the compressed air tank via a copper stamp. By a suitable surge then the welding of the sleeve takes place on the compressed air tank. A particular advantage is that several sleeves can be welded simultaneously in one operation by the use of a corresponding number of copper stamps.

In a particularly advantageous embodiment of the invention can be provided that the sleeve has at its adjacent to the compressed air tank bottom at least one melting edge, which is connected by the CD welding with the compressed air tank. The connection of the sleeve with the compressed air tank is thus not by a flat welding, but only by welding the (preferably annular) circumferential melt edge with the adjacent material of the compressed air tank. The inventor has recognized that a surface welding of the sleeve with respect to the formation of a melting edge on the underside of the sleeve is disadvantageous. It is advantageous if the molten edge extends radially (as far as possible) on the outside of the underside of the sleeve ring. As a result, a radially circumferential gap between the top of the compressed air tank and the underside of the sleeve is avoided. Possibly can be formed on the underside of the sleeve a plurality of circumferential melting edges or more melting points or melting lines may be present. As a result, the welding of the sleeve on the compressed air tank is further improved, however, the melt edges increase the manufacturing cost of the sleeve.

It is advantageous if two annular peripheral melting edges are formed. In this case, a melting edge may be formed radially on the outside circumferentially on the underside of the sleeve and the other radially inside. This avoids that dirt or impurities can penetrate below the sleeve. Optionally, it is also possible to provide a plurality of, for example, five circumferential melting edges.

It is advantageous if a device is provided for carrying out the CD welding process, which has punches which pry the sleeve against the compressed-air container in order to ensure that the sleeve is pressed against the compressed-air container when it is energized. This further improves the welding process. Preferably, the springs press the sleeve with a slight bias.

It when the sleeve has a shape which makes it possible to insert the sleeve at least with a portion in the bore is particularly advantageous. Preferably, the sleeve can be inserted so far into the bore in the shell or in one of the outer floors of the compressed air tank, that the underside of the sleeve is substantially in a plane with the adjacent inner side of the compressed air tank. This prevents dirt and chemical edges. The insertion of the sleeve into the bore can for example be made possible by the fact that the sleeve has an outer diameter which is slightly smaller than the inner diameter of the bore. Optionally, a press fit may be provided. Alternatively, you can also be provided that the sleeve has a Versprung, a nose, a taper or a step which is inserted into the bore. The sleeve can have an overall outer diameter which is greater than the inner diameter of the bore, so that the sleeve can be placed on the outside of the hole and protrudes only the taper or, the projection of the sleeve into the bore. The sleeve can thus lie substantially flat on the outside of the compressed air tank and welded from the outside to the container.

Regardless of whether the sleeve is welded by means of laser or CD welding, it has proven to be advantageous if the region surrounding the bore of the shell and / or the outer floors is flat or flattened. The coat, but also the outer floors usually have a curvature. So far, this has been tolerated and compensated accordingly by the application of welding wire. The inventor has recognized, however, that the welding of the sleeve can be significantly improved if the area to which the sleeve is to be welded has no curvature. A flattening can be produced particularly advantageously by a stamping tool.

According to the invention it is provided that the inner coating of the container is made by a powder coating. In the previously known pressure vessels, the coating was applied by a wet coating method (wet painting). This appeared necessary because of the projections and edges on the inside of the container, it was believed that only by a wet coating process could a complete interior coating be ensured. Now that according to the invention dirt edges and the like are avoided on the inside of the container, the advantages of a powder coating process can be used.

It is advantageous if the powder coating is applied electrostatically to the inside of the container, preferably by a tribo-charging. The inventor has recognized that although the use of a powder coating method is particularly suitable, it can cause problems in the realization. A powder coating of the shell and the outside before they are welded together, has proved to be less suitable. It is more advantageous the powder. only apply when the jacket and the outer floors are welded together. In this case, the problem arises that the powder must be introduced into the pressure vessel. It must also be ensured that the powder adheres to the inside of the container in such a way that a complete and reliable coating is achieved. The inventor has realized that this is best achieved by an electrostatic powder coating process, and more preferably by using a tribo-charge. Generally, an electrostatic powder coating process is understood to mean both corona charging and tribocharging. Corona charging is a high voltage process. In Tribo charging, the powder particles are driven along the surface at high speed, charging them. To insert the powder into the compressed air tank, a tribo lance can be used. Preferably can be used as access opening a sleeve opening or one of the holes in the compressed air tank, preferably one of the holes in the outer bottom of the compressed air tank. Through a nozzle or a spray head at the top of the Tribo lance, the powder charged by the friction can be injected into the interior of the pressure vessel. Due to the charge, the powder settles on the inside of the compressed air tank.

The process of electrostatic charging and the contact on the inner wall is basically known. The inventor has recognized that in the compressed air tank results in an optimal, reliable and uniform powder distribution in the interior of the compressed air tank. This particular, since the geometry was created in the interior of the compressed air tank according to the invention so that no projections and recesses are more present.

According to the invention, it may be provided that the tribo-lance is initially retracted into the compressed-air tank so far that the end of the compressed-air tank remote from the access opening can be provided with a powder layer. During the spraying of the powder, the tribo-lance can then be withdrawn, so that a uniform distribution of the powder is ensured.

The inner coating can then be dried at a temperature of 150 ° to 250 °, preferably 200 ° (+/- 10 °).

In the method according to the invention for producing a compressed air tank for commercial vehicles, it is initially provided that a cylindrical or tubular jacket is bent from a blank. Furthermore, it is provided that two outer floors are produced by drawing or embossing and welded to the end faces of the jacket. At least one outer bottom and / or the jacket are preferably provided prior to welding together with a bore, on which a sleeve is welded. The sleeve can also already be welded on before the jacket is assembled with the outer floors, but also afterwards. It is provided that at least the inside of the compressed air tank is provided with an inner coating. According to the invention, it is provided that the inner coating is produced by a powder coating becomes. Further, the invention provides that the contact surfaces between the shell and the outer floors are designed such that the contact surfaces are flat or blunt abutting each other, after which the contact surfaces are connected without welding material by laser welding. According to the invention it is further provided that the sleeve is applied to the holes by laser welding or by CD welding.

A particularly preferred apparatus for carrying out the method with regard to the production of a powder coating on the inside of the compressed air tank results from claim 13. The device should have a lance, preferably a tribo-lance with a spray head for introduction into the compressed air tank. Furthermore, the device should have a pin with an internal bore for insertion into a bore in the outer bottom for producing an access opening for the lance. Further, a support is to be provided to receive the compressed air tank so that the access opening is oriented downwards. Furthermore, a device should be provided to introduce the lance through the access opening and withdraw it again with the release of coating powder.

It has been found to be advantageous if the introduced into the bolt part of the lance and the spray head has a diameter of at most 20 mm, preferably of at most 15 mm, Thus, the lance can be particularly easy with the spray head through the inner bore of the bolt in the Insert compressed air tank.

It is advantageous if the device has a device for pretreatment of the inside of the compressed air tank. The pretreatment may be to clean the inside of the compressed air tank, for example, degrease, wash and get rid of chemicals. The subsequent coating process is thereby improved.

The tribo-lance can be formed, for example, from a plastic, preferably from polyamide or polyethylene. Preferably, the carrier is designed such that a plurality of compressed air tanks can be attached, for example. Twelve compressed air tanks. It may be advantageous if a corresponding number of tribo lances and bolts is provided.

It is advantageous if the compressed air tank is first fixed on the carrier. Subsequently, the bolt, which is provided with an internal bore, can be introduced into the access opening. The bolt can preferably have an insertion aid, for example a funnel, through which the lance can be inserted.

The apparatus may include means for drying the applied powder. Wherein the device is preferably designed such that the drying at a temperature of 150 ° to 250 ° C, preferably 200 ° C (+/- 10 ° C) takes place. This process is basically known from the prior art.

The tribo-lance can also be made of Teflon or have Teflon. The spray head is preferably designed to be movable in all directions, i. spraying both radially and forwards and backwards.

The claims 1 and 10 claim a particularly advantageous embodiment of the invention or a particularly advantageous method to produce a compressed air tank. The combination of the features 1.1 to 1.3 or the process steps 10.1 to 10.3 lead to a particularly advantageous compressed air tank, the benefits complement each other so that reinforce each other's effects. It should be noted, however, that the features 1.1., 1.2 and 1.3 of claim 1 and the method steps 10.1, 10.2 and 10.3 of claim 10 each taken alone represent an invention. That is, the features 1.1, 1.2 and 1.3 or, the feature.e 10.1, 10.2 and 10.3 need not be combined with each other to represent a solution according to the invention. According to this conviction, the feature 1.1, the feature 1.2 and the feature 1.3 in each case in combination with the preamble in itself constitutes an independent inventive solution to which any claims are still directed. The same applies analogously to the features 10.1, 10.2 and 10.3 of claim 10. The features can of course be advantageously combined with each other in two groups.

Furthermore, the present patent application also includes two independent inventive embodiments of the sleeve. Applicant reserves the right in this respect to make a claim to a sleeve having on its underside at least one circumferential melting edge, as claimed in claim 5. Furthermore, the applicant reserves independently of applying for a sleeve, which is designed according to claim 3.

The present patent application also includes a third inventive embodiment of the sleeve, as shown in claim 6 optionally in combination with claim 7. The Applicant also reserves the right in this regard to make a claim to a corresponding sleeve.

The compressed air tank according to the invention is suitable for any gases.

The compressed air tank may optionally have an integrally formed with the jacket outer bottom, as shown in the FIG. 6 of the DE 20 2005 018 579 U1 is shown.

Advantageous developments and refinements of the invention will become apparent from the further dependent claims. Embodiments of the invention are shown in principle with reference to the drawings.

Fig. 1

Eine perspektivische Darstellung eines Druckluftbehälters;

Fig. 2

einen Längsschnitt durch einen Druckluftbehälter;

Fig. 3

eine Draufsicht auf einen Außenboden eines Druckluftbehälters;

Fig. 4a

einen vergrößerten Längsschnitt durch einen Ausschnitt eines Druckluftbehälters gemäß der Einzelheit IV der Figur 2 im Bereich der Kontaktebene zwischen den Kontaktflächen eines Außenbodens und des Mantels mit schräg verlaufenden Kontaktflächen;

Fig. 4b

einen vergrößerten Längsschnitt durch einen Ausschnitt eines Druckluftbehälters gemäß der Einzelheit IV der Figur 2 im Bereich der Kontaktebene zwischen den Kontaktflächen eines Außenbodens und des Mantels mit gerade verlaufenden Kontaktflächen;

Fig. 5

eine Schnittdarstellung des Bereiches eines Außenbodens in dem eine Muffen auf eine Bohrung geschweißt ist;

Fig. 6

eine besonders geeignete Gestaltung einer Muffe um diese mittels eines außenseitig angesetzten Lasers auf den Druckluftbehälter aufzuschweißen;

Fig. 7a bis 7c

drei weitere geeignete Gestaltungen einer Muffe um diese mittels eines Lasers mit dem Druckluftbehälter zu verschweißen;

Fig. 8

eine Ansicht auf eine Innenseite eines Außenbodens auf welchen außenseitig eine Muffe aufgebracht ist, welche durch einen an der Innenseite angesetzten Laser mit dem Außenboden verschweißt ist;

Fig. 9

eine Ansicht einer Unterseite einer Muffe mit einer Schmelzkante für den Einsatz eines CD-Schweißverfahrens;

Fig. 10

einen Längsschnitt durch einen Druckluftbehälter mit einer prinzipmäßigen Darstellung einer in den Druckluftbehälter eingebrachten Tribo-Lanze; und

Fig. 11

eine vorteilhafte Vorrichtung zur Innenbeschichtung eines Druckbehälters in einer prinzipmäßigen Darstellung.

It shows:

Fig. 1

A perspective view of a compressed air tank;

Fig. 2

a longitudinal section through a compressed air tank;

Fig. 3

a plan view of an outer bottom of a compressed air tank;

Fig. 4a

an enlarged longitudinal section through a section of a compressed air tank according to the detail IV of Figure 2 in the region of the contact plane between the contact surfaces of an outer bottom and the shell with inclined contact surfaces;

Fig. 4b

an enlarged longitudinal section through a section of a compressed air tank according to the detail IV of Figure 2 in the region of the contact plane between the contact surfaces of an outer bottom and the shell with straight contact surfaces;

Fig. 5

a sectional view of the area of an outer bottom in which a sleeve is welded to a bore;

Fig. 6

a particularly suitable design of a sleeve to weld them by means of an externally attached laser on the compressed air tank;

Fig. 7a to 7c

three further suitable designs of a sleeve to weld them by means of a laser with the compressed air tank;

Fig. 8

a view of an inside of an outer bottom on which externally a sleeve is applied, which is welded by an attached on the inside of the laser with the outer bottom;

Fig. 9

a view of a bottom of a sleeve with a melting edge for the use of a CD welding process;

Fig. 10

a longitudinal section through a compressed air tank with a basic representation of an introduced into the compressed air tank Tribo lance; and

Fig. 11

an advantageous device for internal coating of a pressure vessel in a schematic representation.

Compressed air tanks for commercial vehicles are well known from the general state of the art, which is why their basic functioning and their integration into a commercial vehicle will not be discussed in detail below. Only, for example, is on the DE 20 2,005 018 579 U1 and the DE 200 23 422 U1 directed.

The compressed air tank 1 according to the invention is suitable for high pressures, for example, to absorb more than 70 bar.

The Figures 1 and 2 show a compressed air tank 1 for commercial vehicles which is formed from a tubular or cylindrical shell 2 and two outer floors 3. The jacket 2 can be made for example from a correspondingly large board by bending. The outer floors can be prepared in a basically known manner by drawing or by embossing.

The outer floors 3 are cup-shaped in the embodiment or have a recess.

As a material for the jacket 2 and the outer floors 3, various materials are suitable, in the embodiment it is provided that the jacket 2 and the outer floors 3 are made of metal, preferably steel or stainless steel or alloys thereof. Basically, compressed air tank 1 may also be formed of aluminum or aluminum alloys.

In the exemplary embodiment, the compressed air tank 1 has a length between 200 mm and 1400 mm. It has proven to be advantageous to form the shortest container with a length of 200 to 300 mm and the longest container with a length of 1300 to 1400 mm.

As is clear from the FIGS. 1 to 3 shows, the compressed air tank 1 in both the shell 2 and in one of the outer floors 3 holes 4, which can serve to connect different lines, eg. To the consumer or for draining condensation. The holes 4 are each provided with a sleeve 5, which may be provided in the execution area with an internal thread to allow easy connection of continuing lines. The inside 1a of the compressed air tank 1 is provided with an inner coating 6, whose application in the FIGS. 10 and 11 is shown in more detail.

As can be seen in particular from the FIGS. 1 to 4 shows, the shell 2 contact surfaces 2a and the outer floors 3 contact surfaces 3a, which are designed such that the contact surfaces 2a, 3a abutment (or butt, or area) adjacent. The jacket 2 and the outer floors 3 can be welded to each other at the contact surfaces 2a, 3a without welding material by laser welding. A laser 7 used for this purpose is in FIG. 4 shown in principle. In the exemplary embodiment, it is provided that the laser 7 has two laser heads which simultaneously weld the contact surfaces 2a, 3a between an outer bottom 3 and the shell 2. Alternatively, of course, two or more lasers can be used.

It has proved to be advantageous if the jacket 2 has a material thickness of 2.2 mm +/- 0.5 mm.

FIG. 4a shows contact surfaces 2a, 3a which are inclined relative to a radially extending plane of the compressed air tank 1 or have an angle to the radial. Characterized a skew 8 is formed, which may be up to 45 °, preferably 15 °. This results in a self-centering of the outer bottom 3 to the shell. 2

For the preparation of the skew 8 is provided in the embodiment, the edges of the shell 2 and the outer floors 3 to be embossed.

Fig. 4b shows one too Fig. 4a Alternative embodiment of the contact surfaces 2a, 3a, which are not inclined relative to a radially extending plane of the compressed air tank 1 or extend in the plane. The contact surfaces 2a 3a thus encounter straight or flat, ie without inclination against each other. This version is opposite to the one in Fig. 4a preferred embodiment shown.

The holes 4 in the shell 2 and the outer bottom 3 can preferably be introduced by punching. It is provided that the holes 4 and the holes are punched from the inside out. Subsequently, in a manner not shown by means of an embossing die, the area around the bore 4 can be provided with a flattening 9. The flattening 9 is in principle in the FIG. 3 shown. A flattening 9 is provided in the embodiment in all holes 4.

On the bore 4, the sleeve 5 is attached to the outside and welded to the adjacent material of the compressed air tank 1. In the embodiment according to the FIGS. 5 to 9 it is provided that the inner diameter of the bore is larger than the inner diameter of the sleeve. 5

The welding of the sleeves 5 to the compressed air tank 1 is carried out in the embodiment by laser welding or CD welding.

The sleeve 5 is formed in the embodiment of metal, preferably made of steel or stainless steel.

According to FIG. 5 it is provided that the sleeve 5 has a substantially uniform outer circumference. Optionally, it may be provided that the frontal edges are slightly bevelled. According to FIG. 5 is provided that the laser 7 from the outside, that is attached to the outside of the outer bottom or the shell 2. The laser 7 is to weld the sleeve 5 as far as possible radially outward and annularly circumferentially with the adjacent material of the compressed air tank 1. An advantageous positioning of a weld seam 10 produced by the laser 7 is shown in FIG FIG. 5 shown in principle. FIG. 6 shows a particularly suitable design of the sleeve 5 to that according to FIG. 5 perform described laser welding process. The sleeve 5 in this case has a recess 11 and a groove which is arranged in the peripheral wall of the sleeve 5, that between the groove 11 and the groove and the outside of the compressed air tank 1 formed by the sleeve 5 burr 12 or a annular projection remains. The laser beam from the externally applied laser 7 preferably engages in the groove 11 or the groove in order to fuse or weld the ridge 12 or the annular projection of the sleeve 5 to the adjacent material of the compressed-air container 1. A preferably provided positioning of the weld 10 formed thereby is in FIG. 6 shown in dashed lines. The recess may also have a wedge-shaped course, so that below the wedge-shaped groove remains a ridge or an annular projection for welding to the material arranged underneath the compressed air tank. Alternatively, the underside of the sleeve 5 may be circumferentially provided with a chamfer.

The FIGS. 7a to 7c show three particularly suitable designs of sleeves. The FIGS. 7a to 7c also show a particularly suitable solution to weld the sleeve 5 with the compressed air tank 1.

As is clear from the FIGS. 7a to 7c In the preferred embodiment, the sleeve 5 is provided so that it has an outer diameter which is smaller than the inner diameter of the bore 4. Thus, the sleeve 5 is inserted or inserted at least with a portion of its axial length in the bore 4 and there be welded.

The Fig. 7a shows an embodiment in which the sleeve 5 has a substantially constant over its axial length outer diameter having. The sleeve 5 is inserted with an end face into the bore 4 and welded there preferably, the sleeve 5 can be inserted so far into the bore 4, that introduced into the bore 4 underside of the sleeve 5 is substantially flush with the inside of the outer bottom 3 or coat 2 is.

The welding of the sleeve 5 according to Fig. 7a can be done by an externally and / or internally attached laser 7. In Fig. 7a an externally mounted weld 10 is shown.

The advantage of in Fig. 7a The solution shown is that the sleeve 5 is particularly inexpensive, preferably as a turned part, can be produced.

According to the in Fig. 7b and Fig. 7c illustrated embodiment, it is provided that the sleeve 5 has on its bore 4 facing the underside a taper 13 and / or an axial protruding projection and / or a nose. The taper 13 and / or the projection and / or the nose have at least at their end facing away from the sleeve 5 an outer diameter which is smaller than the inner diameter of the bore 4. The sleeve 5 can thus with their taper 13 and the Projection or the nose are inserted into the bore 4, as in the FIGS. 7b and 7c is shown.

According to the in Fig. 7b and Fig. 7c illustrated embodiment can be provided that the taper 13 and the projection or the nose with the sleeve 5 are integral. As further out Fig. 7b and Fig. 7c shows the course of the outer diameter of the taper 13 and the projection or the nose is preferably adapted to the course of the inner edge of the bore 4. As a result, the taper 13 is particularly easy in the Insert hole 4. It also ensures that there is no light gap during laser welding.

As is clear from the FIGS. 7b and 7c shows, the taper 13 or the projection or the nose on an outer diameter which fills the bore 4 at least approximately completely. The weld 10 can be mounted in both embodiments from the inside and / or from the outside. In the FIGS. 7b and 7c a weld 10 is attached from the outside by means of laser welding. This embodiment is preferable.

As it turned out Fig. 7b results, the sleeve in this embodiment, a taper 13 and a projection or a nose with an oblique course. The taper 13 or the projection or the nose have a beveled outer edge, so that the outer diameter of the taper 13 or, the projection or the nose tapers towards its free end. The angle α of the chamfer can be, for example, 30 ° to 70 °, preferably 60 °. The chamfer results in a self-centering.

Fig. 7c shows a particularly preferable embodiment of the sleeve 5. It is provided that the taper 13, the projection or the nose is formed as a stage with a substantially constant outer diameter. The sleeve 5 can be made as a turned part. It is therefore not necessary to produce the bore 4 in the outer bottom 3 or in the jacket 2 with a chamfer. Alternatively, however, a chamfer may additionally be provided in the outer bottom.

By eliminating the chamfer in the outer bottom 3 or in the jacket 2, the bore 4 can be produced in a particularly simple and cost-effective manner by punching.

According to the in Fig. 7b and the in Fig. 7c It can be provided that the underside of the taper 13 extends substantially in a plane with the inside of the outer bottom 3 or of the jacket 2 in the region of the bore 4.

The advantage of in the FIGS. 7a to 7c illustrated embodiments over the embodiments according to the FIGS. 5 and 6 is that no dirt edge formed within the compressed air tank 1, as are avoided by the design and arrangement of the sleeve 5 recesses on the inside of the compressed air tank 1.

Basically, the in the FIGS. 7a to 7c illustrated embodiments with the other features that have been presented with respect to the other embodiments or generally with respect to the invention.

FIG. 8 shows in principle an alternative welding of the sleeve 5 with the compressed air tank 1. It is provided that the laser 7 is attached to the inside of an outer bottom 3. The patch on the outside of the compressed air tank 1 sleeve 5 is thus welded to the bore 4 characterized in that the laser 7 acts on the inside of the outer bottom 3. Preferably, the laser 7 is set so that it welds a radially outer annular surface of the sleeve 5 with the adjacent material of the compressed air tank 1. The radially outer annular surface is in FIG. 8 shown in dashed lines. Since the inner diameter of the sleeve 5 is less than the inner diameter of the bore 4, the inner edge of the sleeve 5 overlaps the inner edge of the bore 4. According to the invention can also be provided that the laser not only an annular surface of the sleeve 5 welded to the adjacent material of the compressed air tank but two or more.

FIG. 9 shows another way to weld the sleeve 5 on the bore 4 and on the compressed air tank 1. For this purpose, a CD welding process is used. The sleeve 5 is attached to the intended location of the compressed air tank 1 and welded by a short surge or the application of the CD welding process with the adjacent material of the compressed air tank 1. As it turned out FIG. 9 results in the sleeve 5 on its underside 5 a on a circumferential edge of fusion 14. The melting edge 14 has an annular course. The melt edge 14 is connected or fused by the CD welding process with the compressed air tank. Preferably, the melt edge 14 has a wedge-shaped course, ie tapers from the bottom 5a of the sleeve 5 in the direction of the compressed air tank 1. If necessary, two or more melt edges 14 may be formed on the bottom 5a of the sleeve 5. It is advantageous if the melt edges 14 radially outwardly annular on the bottom 5a of the sleeve 5 rotates.

The compressed air tank 1 shown in the embodiment has an inner coating 6 on the inside 1a of the compressed air tank, which is manufactured by a powder coating method. In the exemplary embodiment, it is provided that the powder coating is electrostatically applied to the inside 1a of the compressed air tank and this is a Tribo charge is used. As it turned out FIG. 10 results in the embodiment provided that the powder coating is introduced by a tribo-lance 15 in the compressed air tank 1. The tribo-lance 15 in this case has a spray head 16, which emits both radially and forward and backward powder. This is in FIG. 10 shown accordingly.

A particularly suitable device for carrying out the powder coating is in FIG. 11 shown. Here, a carrier 17 is provided to receive a plurality of compressed air tank 1. For each compressed air tank 1, a tribo-lance 15 is provided with a spray head 16. Further, a bolt 18 is provided with an inner bore. The bolt 18 is introduced into a bore 4 in the outer bottom 3 so as to provide an access opening for the lance 15. The part of the tribo lance 15 to be inserted into the bolt 18 and the spray head 16 should preferably have at most an outside diameter of 20 mm, particularly preferably at most 15 mm. Furthermore, the in FIG. 11 The apparatus shown comprises means 19 for introducing the tribo-lances 15 through the access opening and retracting them with the release of coating powder. According to FIG. 11 Furthermore, a device 20 for pretreating the inside 1a of the compressed air tank 1 is provided. Furthermore, a device 21 for drying the applied powder at a temperature of 150 ° C to 250 ° C, preferably 200 ° C is provided. The carrier 17 may be movable by a corresponding suspension. The carrier 17 fixes the compressed air tank 1 both above and below. It is provided that several compressed air tanks 1 are treated simultaneously.

In the embodiment, it is provided that the outside of the compressed air tank 1 is provided with a powder coating.

Claims (15)

1. Compressed-air tank (1) for commercial vehicles, having a tubular or cylindrical casing (2), which is closed at both its ends by welded-on outer plates (3), at least one outer plate (3) and/or the casing (2) being provided with a bore (4), a sleeve (5) being welded on the bore (4) and at least the inner side (1a) of the compressed-air tank (1) being provided with an inner coating (6), characterized in that

   1.1. contact areas (2a, 3a) between the casing (2) and the outer plates (3) are designed in such a way that the contact areas (2a, 3a) adjoin one another in a flush or abutting manner and the contact areas (2a, 3a) are welded to one another without welding material by laser welding;

   1.2. the sleeve (5) is welded on the bore (4) by laser welding or by CD welding; and

   1.3. the inner coating (6) of the compressed-air tank (1) is produced by a powder coating applied electrostatically to the inner side (1a) of the compressed-air tank (1).
2. Compressed-air tank according to Claim 1, characterized in that the laser (7) has two laser heads, which weld the contact areas (2a, 3a) between an outer plate (3) and the casing (2) to one another simultaneously.
3. Compressed-air tank according to either of Claims 1 and 2, characterized in that the sleeve (5) has an indentation (11), a bevel or a groove, which is arranged in such a way that a burr (12), formed by the sleeve (5), or an annular projection remains between it and the compressed-air tank (1).
4. Compressed-air tank according to Claim 3, characterized in that a laser beam of an externally applied laser (7) penetrates into the indentation (11), the bevel or the groove (13) in such a way that the burr (12) or the annular projection of the sleeve (5) fuses with the adjoining material of the compressed-air tank (1).
5. Compressed-air tank according to one of Claims 1 to 4, characterized in that the sleeve (5) has on its underside (5a), adjoining the compressed-air tank (1), at least one at least approximately annularly peripheral fusion edge (14), which is connected or fused to the compressed-air tank (1) by CD welding, the fusion edge (14) preferably being formed as a ring and running around the underside of the sleeve (5) radially on the outside.
6. Compressed-air tank according to either of Claims 1 and 2, characterized in that the sleeve (5) has, on its underside facing the bore (4), a taper (13) and/or an axially prominent projection and/or a protruding nose, the taper (13) and/or the projection and/or the nose having, at least at their end remote from the sleeve (5), an outside diameter which is less than the inside diameter of the bore (4) and the taper (13), the projection or the nose having an outside diameter which at least almost completely fills the bore (4).
7. Compressed-air tank according to Claim 6, characterized in that the taper (13), the projection or the nose has a bevelled outer edge, so that the outside diameter of the taper (13), the projection or the nose tapers towards the free end thereof or the taper (13), the projection or the nose is formed as a step with a substantially constant outside diameter.
8. Compressed-air tank according to one of Claims 1 to 7, characterized in that the region of the casing (2) and/or of the outer plates (3) that is surrounding the bore (4) is flat or flattened.
9. Compressed-air tank according to one of Claims 1 to 8, characterized in that the powder coating is applied to the inner side (1a) of the compressed-air tank (1) electrostatically by a tribo charge.
10. Method for producing a compressed-air tank (1) for commercial vehicles, in particular for air suspensions of commercial vehicles, according to a tubular or cylindrical casing (2) which is bent from a sheet blank, after which two outer plates (3) are produced by drawing or stamping and are welded to the end faces of the casing (2), at least one outer plate (3) and/or the casing (2) being provided with a bore (4) onto which a sleeve (5) is welded, and after which at least the inner side (1a) of the compressed-air tank (1) is provided with an inner coating (6), characterized in that

    10.1. the contact areas (2a, 3a) between the casing (2) and the outer plates (3) are designed in such a way that the contact areas (2a, 3a) can be made to butt flat or flush against one another, after which the contact areas (2a, 3a) are welded to one another without welding material by laser welding;

    10.2. the sleeve (5) is applied to the bores (4) by laser welding or by CD welding; and

    10.3. the inner coating (6) is produced by a powder coating.
11. Method according to Claim 10, characterized in that the powder coating process is an electrostatic powder coating process, preferably using a tribo charge.
12. Method according to Claim 11, characterized in that a tribo lance (15) is used for applying the powder to the inner side (1a) of the compressed-air tank (1).
13. Apparatus for carrying out the method according to Claim 10, characterized by the following features

    13.1. a lance (15) with a spray head (16) for insertion into the compressed-air tank (1);

    13.2. a bolt (18) with an inner bore for insertion into a bore (4) in the outer plate (3), in order to provide an access opening for the lance (15);

    13.3. a support (17) for receiving the compressed-air tank (1) in such a way that the access opening is downwardly aligned; and

    13.4. a device (19) for inserting the lance (15) through the access opening and withdrawing it again while delivering coating powder.
14. Apparatus according to Claim 13, characterized in that a device (21) for drying the applied powder at a temperature of 150° to 250°C, preferably 200°C, is provided.
15. Apparatus according to Claim 13 or 14, characterized in that the part of the lance (15) that can be inserted in the bolt (18) and the spray head (16) have an outside diameter of at most 20 mm, preferably of at most 15 mm.

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