WO2009090012A1 - Arc wire burner - Google Patents

Abstract

The present invention relates to an arc wire burner (1), in particular an internal burner, for the arc wire spraying of workpieces, in particular in hollow bodies, comprising at least one wire (5) acting as melting electrode and comprising 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 spool (8), wherein the wire feed system (2) has a pull-off mechanism (9) for pulling the respective wire (5) off the respective spool (8). The burner (1) has improved flexibility with respect to the usability thereof if a wire magazine (10) is provided for a plurality of spools (8) and the pull-off mechanism (9) is configured such that at least two of the spools (8) can be actuated independently of one another to unwind the wire (5).

Description

 Arc wire burner

The invention relates to a wire arc torch, in particular an internal burner, for the arc wire spraying of workpieces, in particular in hollow bodies, having the features of the preamble of claim 1.

In arc wire spraying, two metallic wires are moved by means of controlled wire feed speed via respective sliding contacts through which electrical current is transferred to the wires in a torch, which may also be referred to as a spray gun. After switching on the wire feed the two spray wires run through the wire guide to each other until it comes to the formation of an arc between the free ends of the spray wires due to the voltage applied. In this arc, an intense heating takes place, whereby the coating material of the wires melts. A gas stream emerging from a nozzle which is expediently integrated in the burner, as a rule an inert gas such as nitrogen, atomizes the resulting melt, accelerates the particles and hurls them onto the surface to be coated. By means of arc wire spraying, for example, the running surfaces of cylinders are coated in piston engines, for example, to reduce the friction between the piston and the cylinder wall. Burners with which such Hollow body of workpieces can be quasi coated from the inside, are also referred to as internal burner.

From DE 102 04 251 Al an arc-wire burner is known, which operates with two serving as a respective melting electrode wires and for this purpose has a wire feed system for supplying the wires to an arc of the burner. The wires are stored on separate coils, wherein the wire feed system has a removal device for removing the wires from the coils. In the known arc wire burner, the two coils are mounted separately and the extraction device pulls the wires from the two coils simultaneously and uniformly.

Further arc wire burners are known, for example, from DE 10 2005 012 360 A1, from EP 1 238 715 A2, from WO 03/066233 A1 and from WO 04/028702 A1.

The present invention addresses the problem of providing an improved embodiment of an arc burner of the type mentioned, which is characterized in particular by the fact that with regard to the wire feed increased flexibility is ensured.

This problem is solved according to the invention 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 to equip the wire feed system with a wire magazine that accommodates a plurality of coils, wherein at the same time the removal device is configured so that at least two of the coils independently of each other for unwinding the wire are controllable. The wire magazine can accommodate two or more coils. It preferably takes on more than two coils, in particular it can be designed to accommodate ten coils. Likewise, a different number of coils is conceivable. As a result of the fact that at least two of the coils can be driven independently of one another for unwinding the wire with the aid of the proposed removal device, there is an increased variability with regard to the supply of the wire (s). For example, in a conventional indoor torch that operates with one arc and two wire electrodes, it may be provided to initially activate only two coils for feeding the wire electrodes while the other coils are deactivated. This means that the feeder pulls the wires only from the two active coils. Once the wires from the two active coils have been completely removed, two other coils can be activated to re-apply 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 realized automatically. Such a design has enormous advantages, since so the arc runner for a correspondingly extended operating time virtually without interruption fully automatic, so with reduced staff costs, can be operated. While in conventional arc wire burners, which have exactly two coils for the two wires, production must be interrupted several times during a shift production during a shift to replace the empty bobbins with full bobbins, which must be done manually, so with manpower the arc wire burner proposed here by a corresponding number of coils in the wire magazine are readily designed so that it throughout the entire Shift duration can work through automatically and almost interruption-free. Replacing the empty bobbins with full bobbins is then only necessary, for example, at or before the beginning of the shift.

Furthermore, there are additional possibilities for electric arc wire burners that work with at least two arcs to which the wires are fed independently. For example, a double burner or dual burner is conceivable in which a priming layer can be applied to the respective workpiece via 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 removal device, the coils assigned to the individual arc can be actuated or activated independently of one another for supplying the wires. That is, the feeder may supply the respective wires to the one arc and independently of the other arc at specific, individually matched wire feed rates. It is also possible first to supply the one wires only to the one arc and then other wires only to the other arc.

Furthermore, it may be necessary to supply the two arc fed wires at different speeds. In particular, the wire feed rates may vary, for example, to produce a coating with a thickness varying alloy on the respective workpiece. It is clear that the mentioned possibilities of variation as well as other possibilities of variation not mentioned here can be combined with each other almost arbitrarily. For example, a torch with two arc can be fed four different wires at individual speeds, and also an automatic change can be done as soon as one of the coils is empty.

Other important features and advantages of the invention will become apparent from the dependent claims, from the drawings and from the associated figure description with reference to the drawings.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination given, but also in other combinations or in isolation, without departing from the scope of the present invention.

Preferred embodiments of the invention are illustrated in the drawings and will be described in more detail in the following description, wherein like reference numerals refer to the same or similar or functionally identical components.

Show, in each case schematically,

Fig. 1 is a greatly simplified, principle view of a

Part of an arc wire burner, Fig. 2 is a representation as in Fig. 1 in the region of a

Burner head, but at another

Embodiment, Fig. 3 is an enlarged view as in Fig. 1 in

Area of a withdrawal facility. According to FIG. 1, a wire arc burner 1, which is preferably an internal burner, comprises a wire feed system 2 and a burner head 3. The arc wire burner 1 is used for arc wire spraying of workpieces, in particular in the case of hollow bodies. For this purpose, the burner 3 works with at least one arc 4, which is indicated in Fig. 1 by a lightning symbol. To produce the arc 4, the arc wire burner 1 uses at least one wire 5 serving as a melting electrode. Preferably, two wires 5 serving as a melting electrode are used to produce the arc 4. The wire feed system 2 now serves to feed the wires 5 to the respective arc 4. It is clear that the burner 3 has corresponding electrical contacts for applying an electrical voltage and for transmitting electrical current to the wires 5 so as to supply the respective arc 4 produce. The burner head 3 can be rotated about a rotation axis 7 in a preferred embodiment by means of a rotary drive 6. This is particularly advantageous when the arc wire burner 1 is designed as an internal burner to coat rotationally symmetric surfaces of hollow bodies. For example, so the treads of cylinders can be coated in piston engines.

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

Furthermore, the wire feed system 2 has a removal device 9, which is designed so that the respective wire 5 can be pulled off from the respective spool 8. The wire feed system 2 also includes a wire magazine 10, here identified by a curly bracket. The wire magazine 10 is used for simultaneous recording of multiple coils 8, so at least two coils 8. In the example takes the wire magazine

10 ten coils 8 on. Preferably, the wire magazine 10 receives more than two, so at least three coils 8.

In connection with this wire magazine 10, the removal device 9 is designed so that it can deduct the wire 5 at least from two of the coils 8 independently. Thus, the take-off device 9 allows for at least two of the coils 8 individual wire feed speeds. In particular, the take-off device 9 can start and end the wire withdrawal or the unwinding of the wire 5 independently of said coils 8. In other words, the extraction device 9 is designed such that it can drive at least two of the coils 8 independently of each other for unwinding the wire 5. Preferably, all coils 8 are independently controllable for unwinding of the wire 5. That is, the take-off device 9 can individually deduct the wires 5 in all the coils 8.

The coils 8 are suitably arranged on a common shaft 11, in such a way that a longitudinal central axis of the shaft

11 coaxial with the winding axes of the coil 8 extends.

The removal device 9 is suitably coupled together with the wire magazine 10 with the burner head 3 so that they can rotate with the burner head 3 about the axis of rotation 7. The removal device 9 comprises a draw gear 12, which can also be arranged on the shaft 11.

According to FIG. 3, a plurality of wires 5 can be threaded simultaneously on the draw gear 12. Preferably, the draw gear 12 may be configured so that in principle all wires 5 of all coils 8 can be threaded simultaneously. The draw gear 12 is designed so that it can produce an individual withdrawal speed for each threaded wire 5. Furthermore, it can be provided that each active coil 8, that is, each spool 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, such that a detachment point of the wire 5 from the winding of the spool 8 essentially retains the same angular position with respect to the draw gear 12. In contrast, the inactive coils 8, ie those from which no wire 5 is unwound, relative to the train gear 12 stationary or rotationally fixed. The draw gear 12 and the take-off device 9 can thus individually fix or drive the individual coils 8 relative to the draw gear 12.

In the event that not all the wires 5 are threaded at the same time on the draw gear 12, the wire feed system 2 can be additionally equipped with a threading device, not shown here, which allows automatic threading of the wires 5 on the train 12.

In order to spray the molten wire material at the respective arc 4 on the surface to be coated of the respective workpiece is, by the Burner head 3 passed through a direction indicated by an arrow gas flow 13, which is expedient radially oriented with respect to the axis of rotation 7. The gas flow 13 takes the melt with it and throws it against the workpiece surface.

While a conventional burner 1 operates with a single arc 4, a special burner 1 is presented in Fig. 2, which operates with two arc 4. In this case, each arc 4 are suitably fed per pair of wires 5 as consumable electrodes. It is clear that more than two arc 4 can be realized. In such an embodiment, the wire magazine 10 stores the coils 8 for all the wires 5, and the take-off device 9 is configured to supply the required wires 5 to all the arcs. In particular, the draw gear 12 or the draw-off device 9 can be configured such that individual wire feed speeds can be set for the individual electric arc 4. For example, it is conceivable to operate the burner 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. Subsequently, only the second arc 4 can then be active, for example, to apply a functional coating to the primer coating. Likewise, it is basically possible to operate the two arcs 4 at the same time in order to be able to apply more coating material in a shorter time. Likewise, alloyed coatings can be realized with different materials, with two arc 4 a total of four wires 5 are supplied from different wire material. The proposed extraction device 9 with the draw gear 12 and the wire magazine 10 allows a high flexibility with regard to the advantageous here individual wire feed.

In order to be able to individually set different wire feed speeds for individual wires 5, the draw gear 12 or the draw-off device 9 can be designed so that the relative rotational speed between the draw gear 12 and the respectively associated coil 8 can be set individually.

With the wire magazine 10 shown in FIG. 1, which is designed to store ten coils 8, it is possible, for example, for the burner 1 operating with only one arc 4 to activate only two coils 8, that is to say for feeding wire 5 to the arc 4 to operate. The removal device 9 thus unwinds only two of the coils 8. As soon as these two coils 8 are empty, the draw-off device 9 activates the two next coils 9. Depending on whether the wires 5 of all the coils 8 are threaded from the beginning on the draw gear 12 or not, can the above-mentioned Threading device are used. As soon as the next coils 8 are empty, a further change to full coils 8 takes place. The two wires 5 of the one arc 4 may require different feed rates, so that the change of the coils 8 can take place 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 supplying other wires 5 to the arc 4. In a burner 1, which operates with two or more arc 4, the magazine 10 may also have for each wire 5, an active coil 8 and at least one further coil 8 for automatically changing. The mentioned variations can be combined with each other as well as with other, not mentioned possibilities.

LIST OF REFERENCE NUMBERS

Wire arc torch Wire feed system Burner head Arc Wire Rotary drive Rotary axis Coil Take-off device Wire magazine Shaft Gear train Gas flow

Claims

claims 1. electric arc wire burner, in particular internal burner, for arc wire spraying of workpieces, in particular in the case of hollow bodies, with at least one wire serving as a melting electrode (5), with a wire feed system (2) for feeding the at least one wire (5) to at least one arc (4), - wherein the respective wire (5) is stored on a spool (8), - Wherein the wire feed system (2) a removal device (9) for withdrawing the respective wire (5) from the respective spool (8), characterized - That a wire magazine (10) is provided for a plurality of coils (8), - That the removal device (9) is designed so that at least two of the coils (8) independently of each other for unwinding of the wire (5) are controllable. 2. electric arc wire burner according to claim 1, characterized in that the coils (8) on a common shaft (11) are arranged. 3. electric arc wire burner according to claim 1 or 2, characterized in that the removal device (9) has a draw gear (12), which can be arranged in particular on the shaft (11). 4. electric arc wire burner according to claim 3, characterized in that all the wires (5) of the coils (8) are threaded on the draw gear (12). A wire arc torch according to claim 3 or 4, characterized in that each active coil (8) relative to the train gear (12) has a relative rotational speed which correlates with the wire feed speed of the respective wire (5) while each inactive spool (8) is relative to the train gear (12) stands. 6. electric arc wire burner according to one of claims 3 to 5, characterized in that a threading device for automatically threading the wires (5) on the draw gear (12) is provided. 7. electric arc wire burner according to one of claims 1 to 6, characterized - That a burner head (3) is provided, on which the at least one arc (4) is generated and from which the respective molten wire (5) with a gas flow (13) is thrown onto a workpiece surface, - That the burner head (3) is rotatable relative to the workpiece about a rotation axis (7), - That the shaft (11) is arranged coaxially with the axis of rotation (7) and is rotationally fixed relative to the burner head (3). 8. arc wire burner according to one of claims 1 to 7, characterized - That the burner (1) for generating at least two arcs (4) is configured, each of which at least one wire (5) can be fed, - that the wire magazine (10) holds in common for all arcs (4) the coils (8) for the wires (5), - That the removal device (9) for supplying the wires (5) to all the arc (4) is configured. 9. electric arc wire burner according to claim 8 and according to one of claims 4 to 6, characterized in that the draw gear (12) is designed so that it can adjust the wire feed speed for the individual arc (4) individually. 10. electric arc wire burner according to claim 9, characterized in that the relative rotational speed between the draw gear (12) and the respective coil (8) is individually adjustable. 11. electric arc wire burner according to one of claims 1 to 10, characterized in that at least two coils (8) for supplying the same arc (4) with wire (5) are provided by the discharge device (9) successively for unwinding and feeding the Wire (5) are controllable.