EP2373920A1

EP2373920A1 - Compressed air tank for utility vehicles and method of manufacture

Info

Publication number: EP2373920A1
Application number: EP09799332A
Authority: EP
Inventors: Wolfgang Petzendorfer; Alexander KÖGEL; Steffen Zanek
Original assignee: Erhard and Soehne GmbH
Current assignee: Erhard GmbH
Priority date: 2008-12-19
Filing date: 2009-12-17
Publication date: 2011-10-12
Anticipated expiration: 2029-12-17
Also published as: MX2011006569A; US20110253727A1; RU2011129823A; CA2759106A1; CA2759106C; BRPI0922432A2; CN102257310A; AU2009327055A1; KR20110113174A; RU2493475C2; DE202009017967U1; EP2373920B1; DE102009020385A1; JP2012512997A; BRPI0922432B1; JP5527746B2; US8978251B2; WO2010070044A1; CN102257310B; KR101690341B1

Abstract

The invention relates to a compressed air tank for utility vehicles, comprising a tubular or cylindrical jacket sealed at both ends by way of welded outer bases. At least one outer base and/or the jacket is provided with a hole. A sleeve is welded onto the hole. At least the inside of the compressed air tank is provided with an inner coating. The contact surfaces between the jacket and the outer bases are adapted such that the contact surfaces abut one another and such that the contact surfaces can be welded together without using any weld material through laser welding. The sleeve is welded onto the hole by way of laser welding or CD welding. The inner coating of the tank is manufactured by powder coating.

Description

Compressed air tank for commercial vehicles and method for its

manufacturing

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 22 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 gas under pressure shaped medium is known for example from DE 20 2005 018 579 Ul.

Conventional pressure vessels have a tubular or cylindrical peripheral wall (shell), the open end faces with corresponding lids (outer floors) closed, usually welded. 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.

DE 20 2005 018 579 Ul describes an advantageous embodiment of a compressed air tank such that at least one outer bottom is formed integrally with the shell. 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 in the prior art by a so-called. Wet coating achieved, but which 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 ümfangswandung (mantle) a so-called. Schmutzkante (also referred to as chemical edge) is formed. Particles or general impurities adhere to this, which then interfere or prevent the application of an inner coating there. The dirt edge, which arises when the outer bottom is connected to the jacket, can be taken, for example, from FIG. 6 of DE 20 2005 018 579 U1. The outer bottom generally has an inwardly tapering bead (insertion bevel) over which the shell or the outer 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. Although the embodiment according to FIG. 1 of DE 20 2005 018 579 U1 avoids such dirty edges, it requires a greater outlay for producing 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 Muffs 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 connections can be found, for example, in FIG. 1 of DE 200 23 422 U1, 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 regard to a compressed air tank to be created by claim 1.

An advantageous method for producing a compressed air tank results from claim 22. An advantageous device for carrying out the method results from claim 25.

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 hitherto 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 (dirt edges or chemical edges) are avoided. This results in a high quality for the paint or the coating. In addition, it is avoided that residues can 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 prepared in such a way that the contact surfaces to be connected can be set against each other in a flat or blunt or dimensioned manner. The case between the contact surface Chen resulting gap should be as low as possible, ie the contact surfaces are machined so precisely that the resulting gap is small, ie 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 skew can be designed both from the inside to the outside sloping and rising. In both cases, a self-centering of the components results in addition, 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 run or lie in a radial plane of the compressed air tank or running in a plane that 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 .Es, if two laser heads are used to weld the orbital weld to connect an outer floor with the shell, which simultaneously weld the contact surface between the outer bottom and the shell. 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 here is that in this case no oxide layer is formed, 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 optical negatively occurring during MAG welding tive weld bead 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 bevel 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. This allows the sleeve to be particularly 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 takes place radially outward and circumferentially on the underside 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 to the outer bottom, since in this case the laser can be attached particularly easily to the inside of the outside. 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. If appropriate, a plurality of circumferential melting edges may be formed on the underside of the sleeve or a plurality of 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. As a result, the welding process further improved. 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, it can also be provided that the sleeve has a projection, a nose, a taper or a step which is inserted into the bore. The sleeve can have a total of an 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 into the bore only the taper or the projection of the sleeve. 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 jacket and / or the outer floors is flat or flattened. Of 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 to apply the powder coating only when the shell and the outer floors welded together are. 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. Tribo charging drives the powder particles along the surface at high speed, charging them up. 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 contact with 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 in particular, since the geometry in the interior of the compressed air tank inventions According to the invention was created so that no projections and recesses are more present.

According to the invention, it may be provided that the tribo-lance is initially retracted so far into the compressed air tank 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, to 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. Furthermore, it is provided according to the invention 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 without welding material are joined together 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 25. 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 proved to be advantageous if the part of the lance to be introduced into the stud and the spray head have a diameter of at most 20 mm, preferably of at most 15 mm. This allows the lance with the spray head particularly easy to bring through the inner bore of the bolt in the compressed air tank. It is advantageous if the device has a device for pretreatment of the inside of the compressed air tank. The pretreatment can be to clean the inside of the compressed air tank, for example. To degrease, wash and free 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 ⁰ 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 such formed so that it sprays in all directions, ie both radially and forwards and backwards.

The claims 1 and 22 claim a particularly advantageous embodiment of the invention or a particularly advantageous method to produce a compressed air tank. The combination of features 1.1 to 1.3 and the process steps 22.1 to 22.3 lead to a particularly advantageous compressed air tank, with the benefits complement each other so that the effects reinforce each other. It should be noted, however, that the features 1.1., 1.2 and 1.3 of claim 1 and the method steps 22.1, 22.2 and 22.3 of claim 22 each individually constitute an invention. That the features 1.1, 1.2 and 1.3 or the features 22.1, 22.2 and 22.3 need not be combined 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 22.1, 22.2 and 22.3 of claim 22. 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. In this regard, the Applicant reserves the right to make a claim to a sleeve which has at least one circumferential melting edge on its underside, such as this is claimed in claim 9. Furthermore, the applicant reserves independently of applying for a sleeve, which is designed according to claim 5.

The present patent application also includes a third inventive embodiment of the sleeve, as shown in claim 13 optionally in combination with claims 14 to 17. 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 outer bottom formed integrally with the shell, as shown in Figure 6 of DE 20 2005 018 579 Ul.

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.

It shows:

Fig. 1 is a perspective view of a compressed air tank;

2 shows a longitudinal section through a compressed air tank. 3 is a plan view of an outer bottom of a compressed air tank.

4a shows 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 obliquely extending contact surfaces.

4b is 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 is a sectional view of the portion of an outside floor in which a sleeve is welded to a bore;

Fig. 6 shows a particularly suitable design of a sleeve to weld them by means of an externally mounted 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;

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

9 shows a view of an underside of a sleeve with a melting edge for the use of a CD welding method;

10 shows 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 shows 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, reference is made to DE 20 2005 018 579 Ul and DE 200 23 422 Ul.

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

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 outdoor floors can be lent known manner be prepared by drawing or by embossing.

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

As material for the shell 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 apparent from Figures 1 to 3, the compressed air tank 1 both in the shell 2 and in one of the outer floors 3 holes 4, which can serve for connection of different lines, eg. To the consumer or for draining condenser water. 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 Ia of the compressed air tank 1 is provided with an inner coating 6, the application of which is shown in greater detail in FIGS. 10 and 11. As can be seen in particular from FIGS. 1 to 4, the jacket 2 has contact surfaces 2 a and the outer bottoms 3 contact surfaces 3 a, which are designed in such a way that the contact surfaces 2 a, 3 a abut (or butt or respectively flat) against one another , 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 shown in principle in FIG. 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 with respect 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 an alternative embodiment of the contact surfaces 2a, 3a, which is an alternative to FIG extending plane of the compressed air tank 1 are not inclined or extend in the plane. The contact surfaces 2a, 3a thus encounter straight or flat, ie without inclination against each other. This embodiment is to be preferred over the embodiment shown in Fig. 4a.

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 of. be punched 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 shown in principle in FIG. 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 exemplary embodiment according to FIGS. 5 to 9, it is provided that the inner diameter of the bore is greater 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. Gegebenen- if it can be provided that the frontal edges are slightly bevelled. According to FIG. 5, it is provided that the laser 7 is applied from the outside, ie on the outside of the outer bottom or the jacket 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 principle in FIG.

FIG. 6 shows a particularly suitable design of the sleeve 5 in order to carry out the laser welding method described according to FIG. The sleeve 5 in this case has a groove 11 or a groove which is arranged in the circumferential 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 seam 10 formed thereby is shown in dashed lines in FIG. The recess may also have a wedge-shaped course, so that below the wedge-shaped groove, a ridge or an annular projection for welding to the underlying arranged

Material of the compressed air tank remains. Alternatively, the underside of the sleeve 5 may be circumferentially provided with a chamfer. Figures 7a to 7c show three particularly suitable designs of sleeves. Figures 7a to Ic also show a particularly suitable solution to weld the sleeve 5 with the compressed air tank 1.

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

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

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

The advantage of the solution shown in Fig. 7a is that the sleeve 5 is particularly inexpensive, preferably as a turned part, can be produced. According to the embodiment illustrated in FIGS. 7b and 1c, it is provided that the sleeve 5 has a taper 13 and / or an axial projecting projection and / or a nose on its underside facing the bore 4. 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 shown in Figures 7b and 7c.

According to the embodiment illustrated in FIGS. 7b and 7c, provision can be made for the taper 13 or the projection or the nose to be integral with the sleeve 5. As is also apparent from FIGS. 7b and 7c, the course of the outer diameter of the taper 13 or 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 can be used particularly easily in the bore 4. It also ensures that there is no light gap during laser welding.

As can be seen from FIGS. 7b and 7c, the taper 13 or the projection or the nose has an outer diameter which at least approximately completely fills the bore 4. The weld 10 can be mounted in both embodiments from the inside and / or from the outside. In FIGS. 7b and 7c, a weld 10 is attached from the outside by means of laser welding. This embodiment is preferable. As is apparent from Fig. 7b, the sleeve in this embodiment has a taper 13 or 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 of the projection or of 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 embodiment illustrated in FIG. 7b and in the embodiment shown in FIG. 7c, it can be provided that the underside of the taper 13 extends essentially in a plane with the inside of the outside bottom 3 or of the shell 2 in the region of the bore 4. The advantage of the embodiments shown in Figures 7a to 7c compared to the embodiments according to Figures 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 ,

In principle, the exemplary embodiments illustrated in FIGS. 7a to 7c can be combined with the further features which have been illustrated with respect to the other embodiments or with regard to the invention in general.

Figure 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 shown by dashed lines in Figure 8. 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 a further possibility for welding the sleeve 5 on the bore 4 or on the compressed-air reservoir 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 can be seen from FIG. 9, the sleeve 5 has a circumferential melting edge 14 on its underside 5 a. 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 starting from the bottom 5a of the sleeve 5 in the direction of the compressed air tank 1. If appropriate, two or more melt edges 14 may be formed on the bottom 5a of the sleeve 5. It is advantageous if the molten edge 14 rotates radially outward annularly on the underside 5 a of the sleeve 5.

The compressed air tank 1 shown in the exemplary embodiment has an inner coating 6 on the inner side 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 applied electrostatically to the inside of the compressed air tank Ia and this is a Tribo charge is used. As can be seen from FIG. 10, it is provided in the exemplary embodiment that the powder coating is introduced into the compressed air tank 1 by a tribo lance 15. The tribo-lance 15 in this case has a spray head 16, both radially as also gives off to the front and to the rear powder. This is shown correspondingly in FIG.

A particularly suitable apparatus for carrying out the powder coating is shown in FIG. Here, a carrier 17 is provided to receive a plurality of compressed air tank 1. For each compressed air tank 1, a tri-lance 15 with a spray head 16 is provided. 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 outer diameter of 20 mm, particularly preferably at most 15 mm. Further, the apparatus shown in Figure 11 comprises means 19 for inserting the tribo lances 15 through the access opening and retracting them while dispensing coating powder. According to FIG. 11, a device 20 for pretreating the inner side 1a of the compressed air tank 1 is also provided. Furthermore, a device 21 for drying the applied powder at a temperature of 150 ⁰ C to 250 ⁰ C, preferably 200 ⁰ 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

Patent claims

1. compressed air tank for commercial vehicles, with a tubular or cylindrical shell which is closed at both ends by welded outer floors, wherein at least one outer bottom and / or the jacket is provided with a bore, wherein on the bore a sleeve is welded and wherein at least the inside of the compressed air tank is provided with an inner coating, characterized in that

1.1. Contact surfaces (2 a, 3 a) between the casing (2) and the outer bottoms (3) are designed such that the contact surfaces (2 a, 3 a) adjoin one another in an abutting or butting manner and the contact surfaces (2 a, 3 a) without welding material by laser welding welded together;

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

1.3. the inner coating (6) of the compressed air tank

(1) is made by a powder coating.

2. Compressed air container according to claim 1 d a d u r c h e g e k e n e c e in that the contact surfaces (2 a, 3 a) extend in a radial plane of the compressed air tank (1).

3. Compressed air tank according to claim 1, characterized in that the contact surfaces (2a, 3a) have a skew (8) of up to 45 °, preferably of 15 ° +/- 5 °.

4. The compressed air tank according to claim 1, wherein the laser has two laser heads which at the same time weld the contact surfaces between an outer bottom and the jacket.

5. Compressed air tank according to one of claims 1 to 4, characterized in that the sleeve (5) has a recess (11), a chamfer or a groove which are arranged such that between these and the compressed air tank (1) through the sleeve (5) formed ridge (12) or an annular projection remains.

6. A compressed air tank according to claim 5, characterized in that a laser beam from an externally applied laser (7) in the groove (11), the chamfer or the groove (13) penetrates such that the ridge (12) or the annular projection of the sleeve (5) merges with the adjacent material of the compressed air tank (1).

7. A compressed air tank according to one of claims 1 to 4, characterized in that the sleeve (5) characterized on the outside of the bore (4) is welded, that the laser (7) on the inside (Ia) of the outer bottom (3) is recognized.

8. A compressed air tank according to claim 7, characterized in that the laser (7) a radially outer annular surface of the sleeve (5) with the adjacent material of the compressed air tank (1) welded.

9. Compressed air tank according to one of claims 1 to 4, characterized in that the sleeve (5) at its on the compressed air tank (1) adjacent underside (5 a) at least one at least approximately annular circumferential melting edge (14) which by CD welding with the compressed air tank (1) is connected or fused.

10. Compressed-air container according to claim 9, characterized in that the melting edge (14) is annular and rotates radially outward on the underside of the sleeve (5).

11. The compressed air tank according to claim 1, wherein the sleeve has an outer diameter that is smaller than the inner diameter of the bore 4.

12. Compressed air tank according to claim 11, characterized in that the sleeve (5) is inserted at least with a portion of its axial length in the bore (4) and welded there.

13. Compressed air tank according to one of claims 1 to 4, characterized in that the sleeve (5) on its bore (4) facing the underside a taper (13) and / or an axially projecting projection and / or a protruding nose, wherein the Rejuvenation (13) and / or the projection and / or the nose at least at its end facing away from the sleeve (5) have an outer diameter which is smaller than the inner diameter of the bore (4).

14. Compressed-air reservoir according to claim 13, characterized in that the course of the outer diameter of the taper (13), the projection or the nose is adapted to the course of the inner edge of the bore (4).

15. Compressed-air container according to claim 13 or 14, characterized in that the taper (13), the projection or the nose has an outer diameter which at least approximately completely fills the bore (4).

Compressed-air reservoir according to one of claims 13, 14 or 15, characterized in that the taper (13), the projection or the nose has a bevelled outer edge, so that the outer diameter of the taper (13), the projection or the nose to the rejuvenated at the free end.

17. The compressed air tank according to claim 13, 14 or 15, characterized in that the taper (13), the projection or the nose is formed as a step with a substantially constant outer diameter.

18. Compressed-air container according to one of claims 1 to 17, characterized in that the area of the jacket (2) and / or the outer floors (3) surrounding the bore (4) is flat or flattened.

19. Compressed-air container according to claim 18, characterized in that the flattening (9) is produced by an embossing tool.

20. Compressed-air container according to one of claims 1 to 19, characterized in that the powder coating is electrostatically applied to the inside (Ia) of the compressed air tank (1), preferably by a tribo-charging.

21. Compressed air tank according to claim 20, characterized in that the inner coating (6) at a temperature of 150 ° to 25O ⁰ C, preferably 200 ⁰ C is dried.

22. A method for producing a compressed air tank for commercial vehicles, in particular for air suspension of commercial vehicles, according to which a tube or a cylindrical jacket is bent from a board, which is followed by Pulling or embossing two outer floors are manufactured and welded to the front sides of the shell, wherein at least one outer bottom and / or the jacket is provided with a bore on which a sleeve is welded, and then at least the inside of the compressed air tank is provided with an inner coating is characterized characterized that

22.1. the contact surfaces (2a, 3a) between the shell (2) and the outer bottoms (3) are designed in such a way that the contact surfaces (2a, 3a) are abuttable against one another in a flat or blunt manner, whereupon the contact surfaces (2a, 3a) pass through without welding material Laser welding are welded together;

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

22.3. the inner coating (6) is produced by a powder coating.

23. The method of claim 22, wherein the powder coating process is an electrostatic powder coating process, preferably using a tribo-charge.

24. The method according to claim 23, wherein the powder is applied to the inside (Ia) of the powder for applying the powder

Compressed air tank (1) a Tribo lance (15) is used.

25. Apparatus for carrying out the method according to claim 22, characterized by the following features

25.1 a lance (15) with a spray head (16) for introduction into the compressed air tank (1);

25.2 a bolt (18) having an internal bore for insertion into a bore (4) in the outer bottom (3) to provide an access opening for the lance (15);

25.3 a support (17) for receiving the compressed air tank (1) so that the access opening is oriented downwards; and

25.4 a device (19) to introduce the lance (15) through the access opening and withdraw it again with the delivery of coating powder.

26. Device according to claim 25, characterized in that a device (20) is provided for the pretreatment of the inner side (Ia) of the compressed air tank (1).

27. The apparatus of claim 25 or 26, characterized in that means (21) for drying the applied powder at a temperature of 150 ° to 250 ⁰ C, preferably 200 ⁰ C is provided.

28. Device according to claim 25, 26 or 27, characterized in that the part of the lance (15) and the spray head (16) insertable in the bolt (18) have an outer diameter of at most 20 mm, preferably of at most 15 mm.