WO2015158458A1

WO2015158458A1 - System and method for the metal coating of a bore wall

Info

Publication number: WO2015158458A1
Application number: PCT/EP2015/054243
Authority: WO
Inventors: Andreas Ebenbeck; Gerhard Aufschläger; Marc Kesting; Ralf VÖLLINGER
Original assignee: Sturm Maschinen- & Anlagenbau Gmbh
Priority date: 2014-04-17
Filing date: 2015-03-02
Publication date: 2015-10-22
Also published as: EP2933352A1; EP2933352B1; PL2933352T3; ES2710712T3; HUE043608T2

Abstract

The invention relates to a system and a method for the metal coating of a bore wall of a bore in a workpiece, in particular a running surface of a cylinder bore in a motor block. A coating lance is inserted into a bore to be coated, a metal plasma jet being produced by the coating lance, and the metal coating is applied onto the bore wall while the coating lance is rotated. The coating lance is moved into multiple bores of the workpiece while the workpiece is stationary using a portal device with at least two movement axes, and the bore walls of the multiple bores are provided with the metal coating by means of the coating lance.

Description

Plant and method for the metallic coating of a bore wall

The invention relates to a system for the metallic coating of a bore wall of a bore in a workpiece, in particular a running surface of a cylinder bore in an engine block, with at least one rotatable coating lance, through which a metal plasma jet for coating the bore wall can be generated, and a conveyor for conveying and Positioning of the workpiece to be coated in a processing position, according to the preamble of claim 1.

The invention further relates to a method for the metallic coating of a bore wall of a bore in a workpiece, in particular a running surface of a cylinder bore in an engine block, in which a coating lance is moved into a bore to be coated, a metal plasma jet is generated by the coating lance and the coating lance is rotated the metallic coating is applied to the bore wall, according to the preamble of claim 11.

In particular, in engine construction, it is necessary to provide the running surfaces of cylinder bores with a special metallic coating, so that adequate friction and lubrication conditions between the cylinder surface and a cylinder piston are ensured. This is especially true when both the engine housing and the cylinder piston are made of the same metal, such as aluminum.

For this purpose, it is known to insert into the motor housing for forming the cylinder surface liners, which are formed of a desired metal material. However, the insertion of such liners in a motor housing component, a so-called engine block, consuming and disadvantageous in terms of wear.

It is known to apply instead of such liners directly on a bore wall, a metal coating by a coating lance, with which a metal plasma jet is generated. In this way, very thin-walled and very stable metal coatings can be formed on bore walls.

A coating device provided for this purpose has a relatively complicated structure, which is due to the supply of the necessary gases and the metallic material. For coating, the motor housing with the respective bore is moved up to the coating lance, so that the motor housing is to be adjusted several times in accordance with the number of holes.

In addition, care must be taken in the coating of such cylinder surfaces that the metallic coating is applied exclusively to the treads. Undue coating on undesired locations can result in failure of such failures during operation of an engine and increased wear on the moving parts of the motor.

A generic system and a generic method are known from DE 199 34 991 A1. For coating cylinder running surfaces in a cylinder crankcase, a lance-like burner is provided, which is movable for coating a plurality of holes between them. During the procedure, the burner can remain switched on. To prevent unwanted coating of the cylinder crankcase during the process of the burner, a mask with a predetermined height is placed on the cylinder bores on the workpiece. The burner can be moved within the cover template. The cover template is provided with a gas supply and must be cleaned regularly by means of a milling device.

WO 2004/005575 A2 discloses a coating installation with a rotary table, on which a cylinder block is centered with respect to the bore to be coated and rotated. A burner with two cooling lances is moved by means of a robot arm into the bore of the rotating workpiece. The invention is based on the object of specifying a system and a method for the metallic coating of a bore wall with which a particularly efficient coating is made possible.

The object is achieved on the one hand with a system having the features of claim 1 and on the other hand with a method having the features of claim 11. Preferred embodiments of the invention are specified in the respective dependent claims.

A system according to the invention is characterized in that a gantry device with at least two travel axes is provided, with which the coating lance for coating a plurality of bores of a workpiece in the processing position can be moved into the bores.

A basic idea of the invention is not to reposition the workpiece with the respective bores for each coating, but rather to machine a plurality of bores in a machining position of the workpiece by moving the coating lance by means of a gantry device and retracting into the respective bores. This can achieve a significant reduction in processing time.

A further aspect of the invention is that the coating lance is adjustable between a retracted movement position and a coating position, that in the coating position, the coating lance is arranged in a bore to be coated in the workpiece, that in the movement position, the coating lance withdrawn from the bore and the Metal plasma jet is directed to a spray shield and that in the movement position, the coating lance is movable together with the spray shield to a coating of a bore in the workpiece. To avoid unwanted Fehlbeschich- tions a spray shield is provided, on which the metal plasma jet is always directed, if this is not arranged together with the coating lance within the bore of the workpiece to be coated. The spray shield can be arranged so that it directly adjacent to the workpiece when the coating lance retracted into the bore of the workpiece or pulled out of the hole. The spray shield is preferably sleeve-shaped.

According to a further embodiment, it is particularly advantageous that the metal plasma jet is generated continuously by the coating lance, regardless of whether the coating lance is in the coating position or the movement position. The metal plasma jet is thus kept in a continuous operation without interruption. As a result, a secure uniform coating on the bore walls is achieved. An otherwise usual switching on and off or raising and lowering of the metal plasma jet is avoided. In the travel position, ie on the way the coating lance between two holes to be coated, the continuously operated metal plasma jet is directed onto the spray shield, so that no unwanted workpiece coatings occur during the movement. As a result, the non-productive time during processing can be further reduced.

A further increase in efficiency is achieved according to a further variant of the invention in that the conveyor is designed as a circulating conveyor, in particular as a turntable, that a loading station and a processing station are provided, in which the coating takes place, and that the workpiece with the Conveyor between the charging station and the processing station is transportable. The circulation conveyor has two or more receiving spaces for workpieces. Thus, during the machining of a workpiece already unload a finished workpiece in the loading station and then loaded a new workpiece. At the conclusion of the processing can then be promoted by a corresponding transport movement, in particular a rotation of the turntable, the new workpiece in the processing station, while the finished workpiece is transported to the loading station for removal.

A further increase in efficiency is achieved according to a further embodiment in that the conveyor has a receptacle for receiving a pallet module, which is designed to hold a workpiece. A pallet module can in particular have the same base area, but the actual workpiece holder on the pallet module is in each case unobstructed. may be formed differently for receiving different workpieces. Thus, despite different workpieces and thus different pallet modules, these are uniformly absorbed by the conveyor.

A preferred embodiment according to the invention is that in the conveyor, the pallet module is adjustable, in particular pivotable. In this way, the cylinder bores can be adjusted in a machined engine block in a favorable working position. For example, an adjustment can be made in a 6-, 8- or 12-cylinder engine block, in which the cylinder bores are arranged in a V-shape. By a corresponding pivoting, the bores to be machined can preferably be aligned in the vertical.

A further improvement of the workflow is achieved according to another method variant of the invention in that an adjustable partition wall is arranged between the loading station and the processing station. Thus, the processing station can be sealed off from the charging station during the coating process.

According to a further embodiment of the invention, it is advantageous that a cleaning station for cleaning the coating lance and / or a measuring station for measuring the metal plasma jet are provided and that the coating lance can be moved with the portal device to the cleaning station or to the measuring station. It is thus possible during operation, a cleaning of the coating lance and also a measurement of the metal plasma jet, so that a reliable operation is ensured with an exact metal coating in a continuous operation. The process is carried out with the portal device. Also during this process the metal plasma jet can be continuously generated further.

A preferred embodiment for the production of the metal plasma jet is according to the invention in that the coating lance comprises a plasma generator, which has a cathode, a metallic anode, which is meltable by an arc between the cathode and the anode, and a nozzle device, through which a gas is conductive, which with metal particles in the Arc forms the metal plasma jet. The Düseneirichtung can generate a gas jet, with which the entrained metal particles are applied from the molten metallic anode in the arc at supersonic speed on the bore wall. The arc is continuously formed by a correspondingly high electrical voltage between the cathode and the anode. The metal plasma jet can also be produced in other ways, for example by injecting metal powder into a plasma jet.

In this case, a preferred embodiment is that the metallic anode is formed by a wire, which is continuously fed via a flexible feed to the movable coating lance. In accordance with the relatively large travel paths or the large traversing space of the coating lance, a flexible feed for the anode wire is provided. The anode wire can be stored as a winding with several 100 meters in length and be conveyed via the flexible feed continuously to the coating lance. Due to the continuous operation of the plasma generator and the coating lance, a uniform feed can be done relatively easily.

The inventive method for metallic coating is characterized in that the coating lance is moved with stationary workpiece with a portal device with at least two axes in several holes of the workpiece, the bore walls of the plurality of holes are provided with the coating lance with the metallic coating.

With this method according to the invention, the advantages described above in connection with the system can be achieved. The process is preferably carried out with one of the above-described plants according to the invention.

A particularly uniform coating with low non-productive times is achieved according to the invention in that, when the coating lance is withdrawn from the coated bore, the metal plasma jet is directed onto a spray shield and the coating lance is moved together with the spray shield. It is avoided as a metal to unwanted locations of the workpiece. In this case, it is preferred according to a further variant of the method that the metal plasma jet is generated continuously by the coating lance, regardless of whether the coating lance is in a processing position, in a bore of the workpiece or outside of the workpiece in a movement position. In this way, the control of the coating lance and the plasma generator for generating the metal plasma jet can be simplified. Also, travel times can be saved, which would otherwise be required for an interruption of the metal plasma jet.

A further increase in efficiency of the method is achieved in that the workpiece is conveyed by a circulation conveyor from a loading station to a processing station, wherein the workpiece is stationary in the processing station, while the plurality of holes are coated by the coating lance.

The invention will be further described below with reference to a preferred embodiment, which is shown schematically in the accompanying drawings. In the drawings show:

Fig. 1 is a schematic side view of an inventive

Investment;

Fig. 2 is a folded through 90 ° side view of the system of Figure 1 in a highly schematic form.

Fig. 3 is a plan view of the system according to Figures 1 and 2; and

4 shows a schematic perspective view of the system according to FIGS. 1 to 3.

An inventive system 10 for the metallic coating of holes 3 in a workpiece 1 is shown in Figures 1 to 4. The workpiece 1 is in the illustrated embodiment, an engine block, with 12 holes 3, which are arranged as cylinder bores in two rows of six in V-shape in the workpiece 1. For receiving a workpiece 1, a conveyor 20 is arranged on a base frame 16, which in the illustrated embodiment as a Turntable 20 is formed. The rotatable about a vertical axis of rotation driven horizontal turntable 20 has two opposite receptacles 23, in each of which a plate-shaped pallet module 24, each with a workpiece 1 is receivable. Via a pivoting device 26, the pallet module 24 can be pivoted with the workpiece 1 relative to the horizontal, so that the holes 3 in the workpiece 1 can be arranged vertically to carry out a metallic coating.

The workpiece 1 is received at a loading station 12 by a feed device (not shown). Subsequently, the turntable 22 is rotated by 180 °, wherein the workpiece 1 is conveyed from the loading station 12 to a processing station 14. In the processing station 14, the workpiece 1 is pivoted with the pivoting device 26 about a horizontal pivot axis, wherein in each case a row of holes 3 is aligned vertically, as shown in Figures 1 and 4 can be seen.

To carry out the metallic coating, a rod-shaped coating lance 30 is provided, which has at its lower end at least one outlet opening 32 for a metal plasma jet. The metal plasma jet is generated in a known manner by a plasma generator with a cathode and a metallic anode. By means of a correspondingly high electrical voltage, an arc is formed between the cathode and the anode, by means of which the metallic anode is melted. The metallic anode is designed as a continuously feedable wire, so that there is always sufficient material to form a metal plasma jet with the molten metal particles. Via a gas nozzle device, a gas stream is generated which emerges at supersonic speed from the outlet opening 32 at the lower end of the coating lane 30 approximately horizontally. In this case, the coating lance 30 with the outlet opening 32 is moved into the bore 3 to be coated in the workpiece 1.

To process the coating lance 30, a portal device 40 with two parallel first track axes 41 is provided. On the two first track axes 41, a frame-like first carriage 47 is mounted horizontally movable. The first traversing carriage 47 itself has two linear, horizontal second traversing axes 42, which are arranged parallel to each other and perpendicular to the first track axes 41.

Along the two second track axes 42, a beam-shaped second carriage 48 is arranged horizontally movable. The second carriage 48 itself has a single vertical third travel axis 43. Along this third travel axis 43, a receiving carriage 45 is mounted vertically movable. On the receiving carriage 45, the coating lance 30 is rotatably supported.

After a workpiece 1 is positioned in the processing station 14, the coating lance 30 is retracted into a first bore 3 to be coated in the workpiece 1. The continuously operated coating lance 30 generates a metal plasma jet which impinges on a bore wall of the bore 3 at supersonic speed. By rotating the coating lance 30 and the axial process in the vertical direction is a uniform defined metallic coating with a thickness of about 10 μιτι on the bore wall.

After moving out of the coating lance 30 from the first coated bore 3 of the metal plasma jet is directed directly at the exit from the bore 3 on a spray shield, not shown, which is supported together with the coating lance 30 on the receiving carriage 45. The spray shield picks up the metal plasma jet and is moved with the coating lance 30 to the next bore 3 to be coated. The metallic coating is then repeated at this second bore 3, with a corresponding coating of the further bore 3 being connected in a row of the workpiece 1. Subsequently, the workpiece 1 can be pivoted about the pivoting device 26 about a horizontal axis, so that the second row of the engine block is arranged for processing in the vertical position. Then, the coating can also connect these six holes 3 in the engine block-like workpiece 1.

After completion of the coating, the coating lance 30 is retracted with the gantry device 40, and the finished coated workpiece 1 can, with simultaneous feeding of a new workpiece to be machined 1 in the La- destation 12 be promoted. From there, a removal of the finished coated workpiece 1 from the receptacle 23 of the turntable 22 can take place.

With the portal device 40, the coating lance 30 can be moved at certain time intervals to a cleaning station, not shown, or to a measuring station, also not shown. In this case, a cleaning of the coating lance 30 or a measurement of the metal plasma jet can be carried out so as to ensure a reliable coating in a continuous operation.

Furthermore, a handling robot 50 may be provided on the turntable 22, which is schematically indicated in Figures 3 and 4. Via the handling robot 50, additional measuring or cleaning functions can be performed on the coating lance 30 or also on the workpiece 1.

Claims

claims

1 . Plant for the metallic coating of a bore wall of a bore (3) in a workpiece (1), in particular a running surface of a cylinder bore in an engine block, with

at least one rotatable coating lance (30), through which a metal plasma jet for coating the bore wall (5) can be generated, and

a conveying device (20) for conveying and positioning the workpiece to be coated (1) in a processing position, wherein the coating lance (30) for coating a plurality of bores (3) of a workpiece (1) in the machining position in the holes (3) is movable and the coating lance (30) is adjustable between a retracted movement position and a coating position, in which the coating lance (30) is arranged in a bore to be coated in the workpiece (1), characterized

in that a portal device (40) having at least two travel axes (41, 42, 43) is provided for moving the coating lance (30), that in the travel position the coating lance (30) is withdrawn from the bore (3) and the metal plasma jet is directed onto a spray shield is and

in that the coating lance (30) can be moved in the movement position together with the spray shield to a coating of a bore (3) in the workpiece (1).

2. Plant according to claim 1,

characterized,

the spray shield is sleeve-shaped.

3. Plant according to claim 1 or 2,

characterized,

the metal plasma jet is generated continuously by the coating lance (30), irrespective of whether the coating lance (32) is in the coating position or the movement position.

4. Plant according to one of claims 1 to 3,

characterized,

in that the conveying device (20) is designed as a circulating conveyor, in particular as a rotary table (22),

a loading station (12) and a processing station (14) are provided, in which the coating takes place, and

the workpiece (1) can be transported with the conveying device (20) between the loading station (12) and the processing station (14).

5. Plant according to one of claims 1 to 4,

characterized,

in that the conveying device (20) has a receptacle for receiving a pallet module (24) which is designed to hold a workpiece (1).

6. Plant according to claim 5,

characterized,

that in the conveyor (20) the pallet module (24) is adjustable, in particular pivotable.

7. Installation according to one of claims 4 to 6,

characterized,

in that an adjustable dividing wall is arranged between the loading station (12) and the processing station (14).

8. Installation according to one of claims 1 to 7,

characterized,

that a cleaning station for cleaning the coating lance (30) and / or a measuring station for measuring the metal plasma jet are provided, and

in that the coating lance (30) can be moved with the portal device (40) to the cleaning station and / or to the measuring station (52).

9. Plant according to one of claims 1 to 8,

characterized,

in that the coating lance (30) comprises a plasma generator which has a cathode, a metallic anode which can be fused by an arc between the cathode and the anode, and a nozzle device through which a gas can be conducted, which with metal particles in the arc forms the metal plasma jet forms.

10. Plant according to claim 9,

characterized,

the metallic anode is formed by a wire, which can be supplied continuously to the movable coating lance (30) via a flexible feed.

11. A method for the metallic coating of a bore wall of a bore (3) in a workpiece (1), in particular a running surface of a cylinder bore in an engine block, in which

a coating lance (30) is retracted into a bore (3) to be coated,

a metal plasma jet is generated by the coating lance (30), while the coating lance (30) is rotated, the metallic coating is applied to the bore wall, and

the coating lance (30) is moved into a plurality of bores (3) of the workpiece (1), wherein the bore walls of the plurality of bores (3) are provided with the coating lance (30) with the metallic coating, characterized,

in the case of a stationary workpiece (1), the coating lance (30) is moved with a gantry device (40) having at least two track axes (41, 42, 43),

in that, when the coating lance (30) is withdrawn from the coated bore (3), the metal plasma jet is directed onto a spray shield and the coating lance (30) is moved together with the spray shield.

12. The method according to claim 11,

characterized,

the metal plasma jet is generated continuously by the coating lance (30), irrespective of whether the coating lance (30) is in a processing position in a bore (3) of the workpiece (1) or outside the workpiece (1) in a movement position.

13. The method according to claim 11 or 12,

characterized,

in that the workpiece (1) is conveyed by a conveyor (20) from a loading station (12) to a processing station (14), wherein the workpiece (1) is stationary in the processing station (14) while the plurality of holes (3) pass through the Coating lance (30) are coated.