DE102008004602B4 - Indoor wire arc torch - Google Patents

Abstract

Internal arc wire torch for arc wire spraying of hollow bodies, - with at least one wire (5) serving as a melting electrode, - with a wire feed system (2) for feeding the at least one wire (5) to at least one arc (4), - the respective Wire (5) is stored on a coil (8), - wherein the wire feed system (2) has a withdrawal device (9) for withdrawing the respective wire (5) from the respective coil (8), - wherein a wire magazine (10) for several spools (8) are present, - the take-off device (9) being designed in such a way that at least two of the spools (8) can be controlled independently of one another for unwinding the wire (5), - a torch head (3) being present which at least one arc (4) is generated and from which the respective molten wire (5) is thrown onto a workpiece surface with a gas flow (13),- the torch head (3) rotating about an axis of rotation (7 ) is rotatable, characterized in that the coils (8) are arranged on a common shaft (11), that the torch (1) is designed to generate at least two arcs (4) simultaneously, each of which has at least one wire (5 ) can be fed, - that the wire magazine (10) stores the coils (8) for the wires (5) together for all arcs (4), - that the withdrawal device (9) for feeding the wires (5) to all arcs (4 ) is designed, - that the extraction device (9) has a traction gear (12) which is arranged on the shaft (11), - that all wires (5) of the coils (8) are threaded on the traction gear (12), and that the traction mechanism (12) is designed in such a way that it can adjust the wire feed speed individually for the individual arcs (4).

Description

The invention relates to an internal arc wire torch for arc wire spraying of hollow bodies.

In the case of arc wire spraying, two metallic wires are moved in a torch, which can also be referred to as a spray gun, by means of a regulated wire feed speed via corresponding sliding contacts, through which electrical current is transmitted to the wires. After switching on the wire feed, the two spray wires run towards each other through the wire guide until an arc is formed between the free ends of the spray wires due to the voltage applied. Intensive heating takes place in this arc, which melts the coating material on the wires. A gas stream emerging from a nozzle expediently integrated into the burner, usually an inert gas such as nitrogen, atomizes the resulting melted material, accelerates the particles and hurls them onto the surface to be coated. With the help of wire arc spraying, for example, the running surfaces of cylinders in piston engines are coated, for example to reduce the friction between the piston and the cylinder wall. Burners, with which such hollow bodies of workpieces can be coated from the inside, are also referred to as internal burners.

From the DE 102 04 251 A1 an arc wire torch is known which works with two wires each serving as a melting electrode and for this purpose has a wire feed system for feeding the wires to an arc of the torch. The wires are stored on separate reels, the wire feed system having a pull-off device for pulling the wires from the reels. In the known wire arc torch, the two coils are stored separately and the pull-off device pulls the wires from the two coils simultaneously and uniformly.

Further arc wire torches are, for example, from DE 10 2005 012 360 A1 , from the EP 1 238 715 A2 , from the WO 2003/066 233 A1 the WO 97/14527 A1 and from the WO 2003/066 233 A1 known.

the DD 2 49 644 A1 describes, quite similar to that DD 2 43 871 A1 a wire arc torch to which several wires are fed to produce 2 arcs at the same time. These can be generated alternately or in parallel. However, the additional wire can be supplied as cold wire.

The present invention deals with the problem of specifying an improved embodiment for an internal arc burner of the type mentioned at the beginning, which is characterized in particular by the fact that increased flexibility is ensured with regard to the wire feed.

According to the invention, this problem is solved by the subject matter of the independent claim. Advantageous embodiments are the subject of the dependent claims.

The invention is based on the general idea of equipping the wire feed system with a wire magazine that accommodates several reels, the withdrawal device being designed so that at least two of the reels can be controlled independently of one another to unwind the wire. The wire magazine can hold two or more reels. It preferably accommodates more than two coils, in particular it can be designed to accommodate ten coils. A different number of coils is also conceivable. The fact that at least two of the coils can be controlled independently of one another for unwinding the wire with the aid of the proposed take-off device results in increased variability with regard to the supply of the wire or wires. For example, in a conventional internal torch that works with an arc and two wire electrodes, it can be provided that only two coils are initially activated for feeding the wire electrodes, while the other coils are deactivated. This means that the pull-off device only pulls the wires from the two active coils. As soon as the wires are completely withdrawn from the two active coils, two other coils can be activated to re-feed the wire electrodes to the arc. The change from the two empty bobbins to the next two bobbins can be carried out in a comparatively short time. In particular, this change can be implemented automatically. Such a design has enormous advantages, since the arc wire torch can thus be operated fully automatically, so to speak, without interruption, for a correspondingly longer operating time, that is to say with reduced personnel expenditure. While with conventional wire arc torches, which have exactly two coils for the two wires, production has to be interrupted several times during a shift in the context of large-scale production in order to replace the empty coils with full coils, which can be done manually, i.e. with personnel expenditure the wire arc torch proposed here can easily be designed by a corresponding number of coils in the wire magazine so that it can work automatically and almost without interruption for the entire duration of the shift. Exchanging the empty bobbins for full bobbins are then only required, for example, at or before the start of the shift.

The wire arc torch according to the invention works with at least two arcs at the same time, to which the wires can be fed independently of one another. Thus, a double burner or double burner is conceivable in which a primer layer can be applied to the respective workpiece using a first arc, for example by means of two wires, while a functional coating can be sprayed onto the primer with a second arc and two other wires. With the proposed wire magazine, for example, four coils can be provided, two each for the two arcs. With the aid of the pull-off device, the coils assigned to the individual arcs can be actuated or controlled independently of one another in order to feed the wires. This means that the extraction device can feed the respective wires to one arc and independently of this to the other arc at special, individually adjusted wire feed speeds. It is also possible to initially feed one wire only to one arc and then only feed other wires to the other arc.

Furthermore, it may be necessary to feed the two wires fed into an arc at different speeds. In particular, the wire feed speeds can vary, for example in order to produce a coating on the respective workpiece with an alloy that varies over the thickness.

It is clear that the mentioned variation options and other variation options not mentioned here can be combined with one another as it were. For example, with a torch with two arcs, four different wires can be fed in at individual speeds, and an automatic change can also take place as soon as one of the coils is empty.

Further important features and advantages of the invention emerge from the subclaims, from the drawings and from the associated description of the figures on the basis of the drawings.

It goes without saying that the features mentioned above and those yet to be explained below can be used not only in the respectively specified combination, but also in other combinations or on their own, without departing from the scope of the present invention.

Preferred exemplary embodiments of the invention are shown in the drawings and are explained in more detail in the following description, with the same reference symbols referring to the same or similar or functionally identical components.

• 1 eine stark vereinfachte, prinzipielle Ansicht eines Teils eines Lichtbogendrahtbrenners,
• 2 eine Darstellung wie in 1 im Bereich eines Brennerkopfs, jedoch bei einer anderen Ausführungsform,
• 3 eine vergrößerte Darstellung wie in 1 im Bereich einer Abzugeinrichtung.

They show, each schematically,

• 1 a greatly simplified, basic view of part of an arc wire torch,
• 2 a representation as in 1 in the area of a burner head, but in a different embodiment,
• 3 an enlarged representation as in 1 in the area of a fume cupboard.

Accordingly 1 comprises an arc wire torch 1, which is an internal torch, a wire feed system 2 and a torch head 3. The arc wire torch 1 is used for arc wire spraying of hollow bodies as workpieces. For this purpose, the torch 3 works with at least one arc 4, which is shown in FIG 1 is indicated by a lightning bolt. To generate the arc 4, the wire arc torch 1 uses at least one wire 5 serving as a melting electrode. Preferably, two wires 5 serving as a melting electrode are used to generate the arc 4. The wire feed system 2 is now used to feed the wires 5 to the respective arc 4. It is clear that the torch 3 has corresponding electrical contacts for applying an electrical voltage and for transmitting electrical current to the wires 5 in order to thus close the respective arc 4 produce. The burner head 3 can be rotated about an axis of rotation 7 by means of a rotary drive 6. This is advantageous because the wire arc torch 1 is designed as an internal torch in order to coat rotationally symmetrical surfaces of hollow bodies. For example, the running surfaces of cylinders in piston engines can be coated in this way.

The wire feed system 2 has a coil 8 for each wire 5. The associated wire 5 is wound onto the respective coil 8. The respective coil 8 thus serves to store the wire 5.

Furthermore, the wire feed system 2 has a withdrawal device 9 which is designed such that the respective wire 5 can be withdrawn from the respective reel 8.

The wire feed system 2 also has a wire magazine 10, which is identified here by a curly bracket. The wire magazine 10 is used to hold a plurality of reels 8 at the same time, that is to say at least two Coils 8. In the example, the wire magazine 10 takes ten coils 8. The wire magazine 10 preferably holds more than two, that is to say at least three, spools 8.

In connection with this wire magazine 10, the withdrawal device 9 is designed such that it can withdraw the wire 5 from at least two of the reels 8 independently of one another. The withdrawal device 9 thus enables individual wire feed speeds for at least two of the reels 8. The withdrawal device 9 can start and end the wire withdrawal or the unwinding of the wire 5 from the said reels 8 independently. In other words, the withdrawal device 9 is designed in such a way that it can control at least two of the coils 8 independently of one another in order to unwind the wire 5. Preferably, all of the coils 8 can be controlled independently of one another in order to unwind the wire 5. That is to say, the withdrawal device 9 can withdraw the wires 5 from all of the coils 8 individually.

The coils 8 are expediently arranged on a common shaft 11 in such a way that a longitudinal center axis of the shaft 11 runs coaxially to the winding axes of the coils 8.

The withdrawal device 9, together with the wire magazine 10, is expediently coupled to the torch head 3 in such a way that it can rotate with the torch head 3 about the axis of rotation 7.

The pull-off device 9 comprises a pulling gear 12, which is also arranged on the shaft 11.

According to 3 several wires 5 can be threaded onto the traction gear 12 at the same time. The traction gear 12 is designed in such a way that all wires 5 of all coils 8 can be threaded in at the same time. The pulling gear 12 is designed in such a way that it can generate an individual withdrawal speed for each threaded wire 5. Furthermore, it can be provided that each active coil 8, that is to say each coil 8 from which the wire 5 is unwound, has a relative rotational speed relative to the traction gear 12. This rotational speed correlates with the wire feed speed of the respective wire 5 in such a way that a separation point of the wire 5 from the winding of the coil 8 essentially retains the same angular position with respect to the traction gear 12. In contrast to this, the inactive coils 8, that is to say those from which no wire 5 is unwound, are stationary or non-rotatable relative to the traction gear 12. The pulling gear 12 or the withdrawal device 9 can thus fix or drive the individual bobbins 8 individually relative to the pulling gear 12.

In the event that not all of the wires 5 are threaded into the traction gear 12 at the same time, the wire feed system 2 can additionally be equipped with a threading device, not shown here, which enables the wires 5 to be automatically threaded into the traction gear 12.

In order to be able to spray the wire material melted on the respective arc 4 onto the surface of the respective workpiece to be coated, a gas flow 13, indicated by an arrow, is guided through the torch head 3, which is expediently oriented radially with respect to the axis of rotation 7. The gas flow 13 takes the melt with it and hurls it against the workpiece surface.

While a conventional torch 1 operates with a single arc 4, in 2 a burner 1 according to the invention is presented, which works with two arcs 4. In this case, each arc 4 is expediently supplied with two wires 5 as melting electrodes. It is clear that more than two arcs 4 can also be implemented. In such an embodiment, the wire magazine 10 stores the coils 8 for all wires 5, and the withdrawal device 9 is designed so that it can feed the required wires 5 to all arcs. The pulling gear 12 or the pull-off device 9 is designed in such a way that individual wire feed speeds can be set for the individual arcs 4. For example, it is conceivable to operate the torch 1 in such a way that initially only the one arc 4 is ignited, for example in order to apply a primer coating to the workpiece surface. Then only the second arc 4 can then be active, for example in order to apply a functional coating to the primer coating. It is also fundamentally possible to operate the two arcs 4 simultaneously in order to be able to apply more coating material in a shorter time. Alloyed coatings with different materials can also be implemented, with a total of four wires 5 made of different wire materials being able to be fed with two arcs 4. The proposed pull-off device 9 with the pulling gear 12 and the wire magazine 10 enables a high degree of flexibility with regard to the individual wire feed which is advantageous here.

In order to be able to individually set different wire feed speeds for individual wires 5, the pulling gear 12 or the pull-off device 9 can be designed such that the relative rotational speed between the pulling gear 12 and the respective associated reel 8 can be set individually.

With the in 1 The wire magazine 10 shown, which is designed to store ten coils 8, can be provided, for example, for the torch 1 operating with only one arc 4, to activate only two coils 8, i.e. to operate them to feed wire 5 to the arc 4. The take-off device 9 thus only unwinds two of the bobbins 8. As soon as these two reels 8 are empty, the take-off device 9 activates the next two coils 9. Depending on whether the wires 5 of all the coils 8 are threaded from the beginning on the pulling gear 12 or not, the aforementioned can be used when changing between the coils 8 Threading device are used. As soon as the next bobbins 8 are empty, there is another change to full bobbins 8. The two wires 5 of the one arc 4 can require different feed speeds so that the bobbins 8 can be changed independently of one another.

Furthermore, it is basically possible to provide the individual coils 8 with different wires 5. This makes it possible to change the coating material fully automatically by feeding other wires 5 to the arc 4.

In the case of a torch 1 that works with two or more arcs 4, the magazine 10 can also have an active coil 8 and at least one further coil 8 for each wire 5 for automatic changing. The possible variations mentioned can be combined as desired with one another and with other options not mentioned here.

List of reference symbols

1

Arc wire torch

2

Wire feeding system

3

Burner head

4th

Electric arc

5

wire

6th

Rotary drive

7th

Axis of rotation

8th

Kitchen sink

9

Deduction device

10

Wire magazine

11th

wave

12th

Traction gear

13th

Gas flow

Claims (6)

Internal arc wire torch, for arc wire spraying of hollow bodies, - with at least one wire (5) serving as a melting electrode, - with a wire feed system (2) for feeding the at least one wire (5) to at least one arc (4), - with the respective Wire (5) is stored on a spool (8), - wherein the wire feed system (2) has a pull-off device (9) for pulling the respective wire (5) from the respective spool (8), - wherein a wire magazine (10) for several coils (8) are present, - the withdrawal device (9) being designed in such a way that at least two of the coils (8) can be controlled independently of one another for unwinding the wire (5), - with a torch head (3) being present which the at least one arc (4) is generated and from which the respective melted wire (5) is thrown with a gas flow (13) onto a workpiece surface, - the torch head (3) rotating relative to the workpiece Axis (7) is rotatable, characterized in that the coils (8) are arranged on a common shaft (11), that the torch (1) is designed to generate at least two arcs (4) simultaneously, each of which has at least one Wire (5) can be fed, - that the wire magazine (10) stores the coils (8) for the wires (5) together for all arcs (4), - that the pull-off device (9) for feeding the wires (5) to all Arc (4) is designed, - that the extraction device (9) has a traction gear (12) which is arranged on the shaft (11), - that all wires (5) of the coils (8) are threaded on the traction gear (12) and - that the traction gear (12) is designed in such a way that it can set the wire feed speed individually for the individual arcs (4). Indoor wire arc torch after Claim 1 , characterized in that each active coil (8) has a relative rotational speed relative to the traction gear (12) which correlates with the wire feed speed of the respective wire (5), while each inactive coil (8) is relative to the traction gear (12). Indoor wire arc torch according to one of the Claims 1 or 2 , characterized in that a threading device is provided for automatically threading the wires (5) on the traction gear (12). Indoor wire arc torch according to one of the Claims 1 until 3 , characterized in that the shaft (11) is arranged coaxially to the axis of rotation (7) and is rotationally fixed relative to the burner head (3). Indoor wire arc torch according to one of the Claims 1 until 4th , characterized in that the relative speed of rotation between the traction gear (12) and the respective coil (8) can be set individually. Indoor wire arc torch according to one of the Claims 1 until 5 , characterized in that at least two coils (8) are provided for supplying the same arc (4) with wire (5), which can be controlled one after the other by the pull-off device (9) for unwinding and feeding the wire (5).

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