DE102010060652A1 - Device for the thermal coating of cylinder inner surfaces in crankcases - Google Patents

Abstract

The invention relates to a device for the thermal coating of cylinder inner surfaces (10) in crankcases (12), with a workpiece holder (16) adapted to the crankcase (12) and with a coating tool (39) that can be inserted into the area of at least one of the cylinder inner surfaces (10). , The device has a suction device (28), which is connected to a vacuum source and is arranged opposite the end face (11) of the cylinder inner surface (10), with a suction opening (30) directed towards the cylinder inner surface (10) and the suction opening (30) surrounds the coating tool (39) supporting tool shaft (38) ring-shaped.

Description

The invention relates to a device for the thermal coating of cylinder surfaces in crankcases, with a adapted to the crankcase workpiece holder and with an insertable into the region of at least one of the cylinder inner surfaces coating tool.

For applying coatings on casting surfaces, thermal spraying methods can be used. Especially the cylinder inner surfaces, d. H. Cylinder-crankcase piston liners are suitable for thermal spray coating. The relatively thin spray coatings offer advantages, especially in aluminum cylinder crankcases, compared to conventionally used cast iron liners, as residual stresses are reduced, overall weight is reduced, and lower friction between pistons and piston liners during engine operation.

For coating, high thermal and kinetic energy processes are used, e.g. As the plasma spraying, the arc wire spraying, laser spraying or flame spraying. In carrying out the coating process, additional reactive gases may be added to assist the process. The spraying materials used are introduced into the energy beam either as wire or as powder, and thrown onto or into the substrate. Suitable materials are pure substances, alloys or mixtures of different compositions. In the case of thermal coating of cylinder inner surfaces in crankcases, the material particles are sprayed with high kinetic energy onto the cylinder inner wall previously prepared with defined roughness, whereby the desired layer thickness of the coating is gradually achieved. A method for appropriate preparation of the cylinder inner wall before the coating is z. B. in the WO 2010/015229 A1 described. In the case of thermal coating, part of the particles bounces off the inner wall and settles on other component parts as an undesirable layer of dirt, or leaves the treatment system together with the exhaust gases. This contamination can negatively affect the process, the plant and the product.

The invention is therefore based on the object safely remove the resulting during thermal spraying of cylinder crankcases gases and dusts from the workpiece.

For this purpose, in a device for thermal coating with the features specified above, a vacuum source connected to the front side of the cylinder inner surface oppositely arranged suction device proposed with a directed towards the cylinder inner surface suction, wherein the suction opening a tool carrying the coating tool annularly surrounds.

With such a device, the gases and dusts accumulating during the thermal spraying of cylinder crankcases can be reliably removed from the workpiece, that is to say the cylinder inner surfaces of the crankcase.

According to one embodiment of the device, the tool shaft is guided sealed by the suction device. Preferably, the tool shaft is rotatably mounted, and sealed by a rotary seal against the suction device.

According to a further embodiment, a component of the suction device is a ring surrounding the suction opening, which, facing away from the crankcase, is designed to be flat, and turned away from the crankcase.

According to a further embodiment, the suction device comprises an at least two-part suction housing, wherein the parts are separable and the tool shank is arranged in the parting plane.

A further embodiment is characterized by a second suction device, wherein this second suction device is part of the workpiece holder. Preferably, the first and the second suction device with a common, d. H. connected to the same vacuum source.

According to a further embodiment, the second suction device has a plurality of suction openings, of which each suction opening is assigned to one of the cylinders of the crankcase.

According to a further embodiment, the suction opening of the second suction device is located at the free end of a projecting into the crankcase, tubular neck, wherein the outer contour of the neck is adapted to the inner contour of the crankcase.

According to a further embodiment, the workpiece holder is rotatable between a first and a second coating position such that in the first coating position one or more left-hand cylinder rows and in the second coating position one or more right-hand cylinder rows of a V-engine or a double V-engine are processed can be.

Further details and advantages of the invention will become apparent from the following description of embodiments, reference being made to the drawings. Show:

1 in a first embodiment, a vertical cross-section through the device, attached to the crankcase of a straight-line engine;

2 one compared to 1 rotated 90 °, second vertical cross section of the first embodiment;

3 a plan view of the first embodiment;

4 in a second embodiment, a vertical cross section through the device, set in a first coating position to the crankcase of a V-engine;

5 one of the 4 Comparable side view of the second embodiment, in a second coating position.

To solve certain technical problems, in particular tribological problems, it is often desirable to coat surfaces of a substrate with a material that has very specific, optimally adapted to the particular conditions of use properties. Such coatings have the advantage of an extremely compact design combined with a relatively large contact surface of the adjacent materials, as compared to solutions in which several components are joined together either mechanically or by adhesive or solder joints, resulting in such a connection technology, especially for thermally highly stressed components offering. The coating results in a very good adhesion, so that thermal energy can be dissipated particularly well.

In the field of metallic materials such coatings are often applied by so-called "thermal spraying", here in addition to the so-called flame spraying in recent times frequently the so-called plasma spraying or arc spraying is used. Here, powder and / or wire particles with high thermal and kinetic energy are thrown or sprayed onto the surface of the substrate to be coated and form there after the temperature dissipation of the desired application layer.

In addition to a precise compliance with the process parameters to avoid so-called build-up dorosities, d. H. the incorporation of no longer fillable cavities or of so-called "overspray", in which a part of the unfused particles does not adhere to the substrate but bounces off, it is crucial for a reliable use of this manufacturing process on the mechanical interlocking between the coating and substrate to to achieve a sufficiently high level of coating adhesion. In such a case, there is a need to form the substrate surface with a surface structure of predetermined geometry so that the layer uniformly mechanically interlocks over the entire surface to be coated. It has been found that in many cases it is not sufficient to roughen and / or activate the substrate surface, for example by sand blasting or water jets.

For example, when a cylinder crankcase is provided with suitable coatings applied by thermal spraying, a wear resistant and low friction tread is created.

In the 1 to 3 a first embodiment of the device for the thermal coating of cylinder inner surfaces is shown 10 in cylinder crankcases 12 made of cast iron or an aluminum or magnesium alloy, as well as the cylinder crankcase to be machined 12 , here the crankcase of a four-cylinder in-line engine.

The cylinder crankcase to be machined 12 rests on a workpiece holder 16 from. Integrated into this is a first suction device 18 , The suction device 18 has four lower cylinder openings for each of these 20 of the crankcase 12 a separate suction opening 22 on. To the inner contour of the crankcase 12 customized essays 24 the suction device protrude close to the cylinder inner surfaces to be coated 10 in the crankcase 12 in, and are at their upper end with to the cylinder inner surfaces 10 open suction openings 22 Mistake. In 2 is in a further side view of the device and the crankcase, the adaptation of the geometry of the essays 24 the lower suction device 18 to the inner contour of the crankcase 12 to recognize more precisely.

In the 1 and 2 are the essays 24 cylindrical and straight. Often, however, cylinder crankcases are provided with undercuts in which straight designed essays can not be driven sufficiently far. For this case, it may be beneficial to the essays 24 two or more parts run, so as to fully retract even under undercuts of the crankcase, and to be able to extend after completion of the process again.

The essays 24 are designed such that the surrounding contour of the crank space remains a certain gap. Through this gap, a secondary flow is possible, also in this way tolerances between the contour of the essay 24 and the surrounding contour of the crank chamber.

At the other end, here above the crankcase 12 and thus, where the cylinder head sits in the later combustion engine, there is one on a bracket 26 fixed second suction device 28 with only one suction opening here 30 that is, only one of the cylinder openings 36 is open.

Deviating from this embodiment, but also several cylinders of the cylinder crankcase 12 treated simultaneously, ie worked in it and sucked out of it.

Both suction devices 18 . 28 are connected to vacuum sources, not shown in the figures, wherein advantageously the same vacuum source both suction devices 18 . 28 supplied with negative pressure.

The suction opening of the suction device 28 is as a preferably circular ring opening 30 configured, whose diameter to the contour of the individual cylinder opening 36 of the crankcase 12 is adjusted. For better sealing of the transition between the upper suction device 28 and the cylinder opening 36 has the upper suction device 28 at the bottom of a suction housing 32 one the suction opening 30 surrounding ring 34 on, the opening of which from the suction housing 32 in the direction of the crankcase 12 having decreasing inner diameter. This can lead to improved flow guidance and an improved suction effect. Of additional advantage is when the ring 34 provided with a wreath placed thereon. This wreath prevents particles from getting back into the cylinder opening 36 fall behind.

By appropriate process control, the suction device 28 each aligned so that the suction opening 30 and the ring 34 exactly above a single cylinder opening 36 of the crankcase 12 are arranged. A a coating tool 39 for thermal spraying bearing tool shank 38 is so coaxial with the respective cylinder inner surface 10 through the suction housing 32 passed through the tool shank 38 exactly in the middle both through the upper suction device 28 and the ring 34 leads, as well as centric in the respective cylinder of the crankcase 12 leads.

Preferably, the tool shank 38 opposite the upper suction device 28 sealed, wherein it can be rotatable, as well as further vertically translationally displaceable. This is a maintenance of the negative pressure, even with a rotation of the tool shank 38 for uniform coating of the cylinder inner surfaces 10 or with a linear movement of the tool shank 38 for insertion and removal of the coating tool 39 in and out of a cylinder, guaranteed.

With the tool 39 For example, the cylindrical inner surface, ie, the custom-machined bore of the cylinder crankcase, is machined to apply a layer by thermal spraying. By this material application by so-called thermal spraying creates a socket z. As steel with traces of other elements, in the form of a matrix with embedded oxide and very fine pores. The finished oversize of this layer should then be about 0.1 to 0.2 mm, whereby after honing this layer a very smooth surface with very fine pores is formed.

The suction devices 18 . 28 are mounted relative to each other displaceable. This allows the coating tool 39 along a row of cylinders of a cylinder crankcase 12 to move to the next cylinder to be coated. In this case, either the upper suction device 28 including the coating tool 39 along the front side 11 of the crankcase 12 be moved or the lower suction 18 including the crankcase 12 below the coating tool 39 be moved.

In particular the 3 it can be seen that the suction housing 32 with an opening mechanism 40 is provided for cleaning. This is the suction housing 32 formed in two parts, with a vertical parting plane 42 exactly in the middle through the upper suction opening 30 , The ring 34 and the tool shank 38 leads. On the outer contour of the suction housing 32 is on one side of the two parts of the suction housing 32 connecting hinge 44 and on the other side a tension lock 46 for opening and closing the upper suction device 28 intended for cleaning purposes.

In the suction housing 32 there is a grid serving as a filter. This retains extracted particles so that they do not get into the area of the exhaust fan. The filter or grid can be opened after opening the upper suction device 28 to replace it or to clean it before reinstalling.

The essays 24 and the rings 34 consist of a material that largely prevents particle buildup. Suitable for this is z. As a copper-nickel alloy.

In 4 and 5 a second embodiment of the device for the thermal coating of cylinder inner surfaces is shown 10 in crankcases 12 in which the upper suction device 28 in the 1 to 3 shown first embodiment corresponds, however, the lower suction device 18 is configured such that the cylinder inner surfaces 10 of different cylinder rows 48 . 50 a V-engine can be coated. For this purpose, as in the first embodiment, the lower suction device 18 into the workpiece holder 16 integrated. The workpiece holder 16 is between a in 4 shown first coating position for coating the cylinder inner surfaces 10 the left cylinder bank 48 and a second coating position for coating the cylinder inner surfaces 10 the right cylinder bank 50 the V-motor rotatably and stored accordingly on a stationary frame. This has the advantage that the upper suction 28 with the elements and tools of the thermal coating system does not have to be rotated to all cylinder rows 48 . 50 to coat the V-engine. The device after the 4 and 5 is suitable not only for the machining of V-engines, but for all engines with multi-bank cylinder arrangement, such. B. also double V-engines.

Center integrated in the workpiece holder 16 and in the flow path of the lower suction device 18 is a passage valve 52 , which depending on the rotational position of the workpiece holder 16 the negative pressure in the corresponding cylinder bank 48 . 50 , so in the respective essays 24 passes. The passage valve remains 52 essentially unchanged in its position. The switching of the corresponding flow path through the lower suction device 18 takes place by rotation via an actuator from one to the other coating position.

The passage valve 52 is on the rotation axis 54 the workpiece holder 16 arranged so that the workpiece holder 16 around the flow axis of the gate valve 52 rotated, and no connections in the context of the rotation of the workpiece holder need to be changed or re-laid.

In the embodiments described above, only one coating tool is provided for each cylinder crankcase, and the suction takes place only in the region of the cylinder inner surface surrounding this tool. In the context of the invention, it is also possible to coat more than one cylinder of the crankcase at the same time and in this case to perform the suction described.

LIST OF REFERENCE NUMBERS

10

Cylinder inner surface

11

front

12

crankcase

16

Workpiece holder

18

lower suction device

20

lower cylinder opening

22

lower suction opening

24

Essays

26

bracket

28

upper suction device

30

Suction / ring opening

32

extraction housing

34

ring

36

cylinder opening

38

tool shank

39

coating tool

40

opening mechanism

42

parting plane

44

hinge

46

Lever Release

48

left cylinder bank

50

right cylinder bank

52

Gate valve

54

axis of rotation

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2010/015229 A1 [0003]

Claims (10)

Device for the thermal coating of cylinder surfaces ( 10 ) in crankcases ( 12 ), with one to the crankcase ( 12 ) adapted workpiece holder ( 16 ) and with one in the region of at least one of the cylinder inner surfaces ( 10 ) insertable coating tool ( 39 ), characterized by a connected to a vacuum source, the front side ( 11 ) of the cylinder inner surface ( 10 ) arranged opposite suction device ( 28 ) with one to the cylinder inner surface ( 10 ) directed towards the suction opening ( 30 ), wherein the suction opening ( 30 ) a the coating tool ( 39 ) carrying tool shank ( 38 ) surrounds annularly. Device according to claim 1, characterized in that the tool shank ( 38 ) through the suction device ( 28 ) is passed, preferably sealed by the suction device ( 28 ) is passed. Device according to claim 2, characterized in that the tool shank ( 38 ) rotatably mounted and via a rotary seal against the suction device ( 28 ) is sealed. Device according to one of the preceding claims, characterized in that part of the suction device ( 28 ) the suction opening ( 30 ) surrounding ring ( 34 ), which is the crankcase ( 12 ) facing flat, and the crankcase ( 12 ) facing away from the suction opening ( 30 ) is sloping. Device according to one of the preceding claims, characterized in that the suction device ( 28 ) an at least two-part suction housing ( 32 ), wherein the parts are separable and the tool shank ( 38 ) in the parting plane ( 42 ) is arranged. Device according to one of the preceding claims, characterized by a second suction device ( 18 ), wherein the second suction device ( 18 ) Part of the workpiece holder ( 16 ). Apparatus according to claim 6, characterized in that the second suction device ( 18 ) a plurality of suction openings ( 22 ), of which each suction opening ( 22 ) one of the cylinders ( 14 ) of the crankcase ( 12 ) assigned. Apparatus according to claim 6 or 7, characterized in that the suction opening ( 22 ) of the second suction device ( 18 ) at the free end of one in the crankcase ( 12 ) projecting, tubular essay ( 24 ), and that the outer contour of the attachment ( 24 ) to the inner contour of the crankcase ( 12 ) is adjusted. Device according to one of the preceding claims 6, 7 or 8, characterized in that the workpiece holder ( 16 ) is rotatable between a first and a second coating position such that in the first coating position a left-hand row of cylinders ( 48 ) and in the second coating position a right cylinder row ( 50 ) of a V-engine or double V-engine is workable. Device according to one of the preceding claims, characterized by a in the suction device ( 28 . 18 ), interchangeable filter.

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