WO2011092222A1

WO2011092222A1 - Crankshaft

Info

Publication number: WO2011092222A1
Application number: PCT/EP2011/051092
Authority: WO
Inventors: Rainhard Laag; Jochen Schmidt; Martin Plew
Original assignee: Maschinenfabrik Alfing Kessler Gmbh
Priority date: 2010-01-27
Filing date: 2011-01-26
Publication date: 2011-08-04
Also published as: DE102010001283A1

Abstract

The invention relates to a crankshaft (1) having a main body made of a metal material having at least two primary bearing journals (2) and at least one connecting-rod journal (3) and a plurality of radii (7), wherein at least one of the primary journals and/or one of the connecting-rod journals and/or one of the radii has a coating (6) made of a material which has a higher elasticity module than the material of the main body of the crankshaft.

Description

crankshaft

The invention relates to a crankshaft with a base body made of a metallic material, which has at least two main ^¬ bearing pin and at least one connecting rod journal. Furthermore, the invention relates to a method for producing a crankshaft, wherein in a first step, a base body is made of a metallic material, which we ^¬ least two main journal and at least one connecting rod journal.

From the prior art, various designs of crankshafts are known. While the torsional strength and the fatigue strength of modern crankshafts are usually less problematical, the required bending stiffness of crankshafts often leads to problems in the dimensioning of the bearing points, which are particularly stressed in diesel engines with high torques. This usually results in relatively large bearing diameters, which are associated with a corresponding increase in the mass of the crankshaft.

In DE 10 2007 018 230 AI a method for producing a crankshaft from ADI casting is described in which after a ADI heat treatment, a thin coating is applied to the bearing surfaces to allow mechanical processing of the bearing surfaces, ie the coating should be better workable than the base material of the crankshaft. In the ^¬ se way, the dimensional accuracy of the bearing surfaces for connecting rods and shaft bearings should be ensured in a simple manner. From DE 10 2006 061 499 AI a crankshaft is known, the pins are coated with bearing material. In the bearing ^¬ material may be white metal to act a copper alloy or an aluminum alloy, wherein the bearing material is softer than the mating surface of the bearing, thus eliminating the need in the crankcase and in the connecting rod bearings. A sliding layer of plain bearings, especially for crankshafts ^¬ or connecting rod is known from DE 10 2004 045 110 B3. Accordingly, this sliding layer is not applied to the Kurbelwel ^¬ le, but on the counterpart, so for example on the Kur ^¬ belgehäuse.

It is an object of the present invention to provide a crankshaft and a method for the production thereof, which has a higher bending stiffness with at least not increased outer dimensions.

According to the invention this object is achieved by the ge in claim 1 ^¬ called features.

Due to the inventive coating of the material, which has a higher modulus of elasticity than the material of the base ^¬ body of the crankshaft, at least one of

Journal and / or on at least one of the radii advantageously results in an increase in the bending stiffness of Kur ^¬ belwelle in this area. A particular advantage is that the radius of received stiffness with the 4th power in the calculation of the bending, and therefore a coating of a Materi al ^¬ with a higher modulus of elasticity has a particularly high effect just at the outer periphery of the bearing. Especially It is part of this that this increase in bending stiffness does not increase the diameter of the bearing and thus, depending on the material used for the coating, no or only a small increase in the mass of the crankshaft result.

By increasing the flexural rigidity of the crankshaft also results in a greater smoothness of the same and thus the entire engine equipped with the crankshaft engine, so that may possibly be dispensed with hitherto installed balance shafts, which makes significant cost savings possible. Such a cost saving can cancel out any additional costs for the coating according to the invention by far. Depending on the material used for the coating, it may even be possible to dispense with an inductive or otherwise performed hardening of the crankshaft and the subsequent stress relief annealing and possibly also on a subsequent deep rolling, resulting in a considerable simplification of the production of Crankshaft has the consequence and thus can greatly reduce their production costs.

To achieve the possible need for the manufacturer increase in rigidity, it is also possible that only the radii and not also the running surfaces of the cure ^¬ belwelle are provided with the coating. Thus, the increase in mass and possibly expect ^¬ Tenden difficulties in the processing of coated crankshaft may optionally minimized or reduced, eliminated, at best, particularly when the coated radii do not have to be finished. With regard to increasing the bending stiffness of the crankshaft on the one hand and the procedural effort on the other hand, it has proven to be particularly advantageous if the coating has a thickness in a range of 0.5 to 5 mm, preferably 0.8 to 4.5 mm more preferably 0.9 to 4.0 mm, most preferably 1.0 to 3.5 mm. With these values, an optimum ratio between the increase of the elastic modulus, and thus the rigidity of a part, and the Mas can ^¬ senzunahme other hand reach.

Although in principle it is also possible to provide only one or a specific individual one of the bearing points of the crankshaft according to the invention with the coating, for example if it concerns individual, particularly heavily loaded bearing journals, it is with regard to increasing the flexural rigidity of crankshaft as well as in terms of ^Einfachfa tion of the method, however, particularly advantageous if a plurality of main journal and / or connecting rod journal, and / or radii have the coating.

Furthermore, it can be provided that the coating is provided on at least one of a main journal and / or connecting rod journal in a crank web passing radius and / or provided on a journal bearing journal and / or on a flange bearing pin and / or on a support bearing journal radius is. Since just the transition from the bearings in the crank arms, preferably designed as radii Ü- transition areas are exposed to a particularly high load, in this way an increase in the bending stiffness in said areas is possible. The maximum gain in stiffness as a result of the higher elastic modulus of the Beschich ^¬ processing can be achieved when a large as possible surface of the crankshaft having the coating. However, ever After loading the crankshaft in operation, even at individual provided on a journal bearing journal and / or on a flange bearing pin such loads occur that it may be advantageous to provide only certain radii with the coating. This can achieve a reduction in the mass increase possibly resulting from the coating.

It can be provided that the radius has a respect to the outer contour of the crankshaft recessed in the radial and / or axial direction depression, which is at least approximately filled with the Materi ^¬ al the coating. In this way, the desired amount of the coating material can be accommodated in the area of the highly loaded radius, without enlarging the contour and thus the volume of the crankshaft or its required installation space.

In order to avoid that possibly a higher hardness or a higher strength or a coating material having other reasons machinability after his

Insertion into the recess must be mechanically processed, can be provided in a very advantageous embodiment of the invention that the recess is filled with the material of the coating such that the coating receded relative to a peripheral surface of an adjacent journal and / or a plane surface of an adjacent crank arm is. As a result, there are almost no changes to the previous manufacturing process in the finishing, in the type of tools and in the preparation and implementation of the processes. A further advantage is that the coating material having a higher modulus of elasticity is completely retained in this way, which leads to an increase in the maximum rigidity. In order to be able to apply the coating in a particularly simple manner to the material of the base body, it can be provided in a further advantageous embodiment of the invention that the material of the coating is a metal which is selected from the group consisting of tungsten, cobalt, molybdenum , Beryllium, aluminum, titanium, iron or alloys comprising at least one of these materials. It is crucial that the modulus of elasticity of the material used is higher than the modulus of elasticity of the material of the main body.

Alternatively, it may be provided that the material of the coating is a ceramic material selected from the group consisting of aluminum nitride, aluminum oxide, silicon carbide, silicon nitride, tungsten carbide and boron carbide.

Such ceramic materials have a very good ratio of high elastic modulus to low density and therefore offer themselves to increase the flexural rigidity while reducing the mass of the crankshaft.

If the is further provided that the base body at least partially, preferably completely, of an iron or aluminum ^¬ miniumwerkstoff, it may be resorted to proven techniques for the manufacture ^¬ position of the base body.

In order to achieve a sufficiently large effect when using the coating Inventive ^¬ according to may in particular achieve an optimal increase in stiffness of the crankshaft, may be seen upstream, in a further advantageous embodiment of the invention is that the modulus of elasticity of the material of Be ^¬ coating at least 10 kN / mm ² , preferably 30 kN / mm ² , even more preferably ^¬ 50 kN / mm ² , is greater than the modulus of elasticity of Ma ^¬ material of the body. Preferably, the crankshaft is made by forging. Forged crankshafts meet high demands on dynamic strength and rigidity, especially when made of tempered steels. In principle, however, the crankshaft can also be produced by casting.

A method for producing a crankshaft is specified in claim 12.

By this method can be according to the invention cure ^¬ belwelle very easily prepared, being able to be in Depending ^¬ ness may be omitted from the one used for the coating material to one or more previously required method ^¬ steps, such as hardening, stress relief annealing and hard rolls , In this way, there is another potential for saving costs.

With regard to the application of the coating to the base body of the crankshaft, it can be provided in an advantageous development of the method that the coating is applied by means of thermal spraying, high-speed flame spraying, atomizing from the melt, plasma coating or laser remelting.

One possibility of realizing a known oil supply to the connecting rod bearings and possibly also to the main bearings can be that at least one oil hole is introduced into at least one of the main bearing pins and / or at least one of the connecting rod ^journal pins before the coating is applied , And that the oil hole is kept closed during the application of the coating so that the material of the coating does not penetrate into the oil hole. Alternatively, it can also be provided for the realization of an oil supply that after the application of the coating in at least one of the main journal and / or in at least one of the connecting rod journal an oil hole is introduced. As a result, it is possible to dispense with the closing of the oil bore and the closure elements required for this purpose.

Hereinafter, an embodiment of the invention with reference to the drawing is shown in principle.

It shows:

Fig. 1 is a side view of a crankshaft according to the invention;

2 is an enlarged view of a bearing point of the crankshaft according to the invention.

3 is a schematic representation of a step in the application of the coating according to the invention to a section of the crankshaft according to the invention;

4 is a schematic diagram for illustrating the advantages of the coating according to the invention;

5 shows a first possibility for applying the coating in the region of a radius;

6 shows a second possibility for applying the coating in the region of a radius; Fig. 7 is a schematic representation of a first location where a radius provided with a coating may be located;

Fig. 8 is a schematic representation of a second location where a radius provided with a coating may be located;

9 shows a first possibility for attaching an oil hole to a bearing journal of the crankshaft according to the invention; and

Fig. 10 shows a second way of attaching an oil hole on a journal of the crankshaft according to the invention.

Fig. 1 shows a very schematic view of a crankshaft 1, which in a conventional manner a plurality of bearing points, namely a plurality of main journals 2 and a plurality of connecting rod journals 3, has. Between the main journal 2 and the connecting rod journal 3 are respective crank webs 4. Here, the number of main journal 2 and the number of connecting rod journal 3 is not important, d. H. The crankshaft 1 could also have various other shapes or configurations than those illustrated.

In Fig. 2, one of the main journals 2 is enlarged and shown in section. Together with corresponding bearing shells or the like, which are associated with a crankcase of a Brennkraftma ^¬ machine, form the main bearing pin 2 respective bearings or bearings of the crankshaft 1. Similarly, this applies to the connecting rod bearing journal 3, which with corresponding bearings of a connecting rod, not shown, a connecting rod bearing form. It can be seen that the crankshaft 1 has a base ^¬ body 5, at least over part of its surface -lo ^¬

che is provided with a coating 6. The coating 6 is made of a material which has a higher elasticity modulus than the ^¬ material of the body 5 of the crankshaft 1 to ^¬. In this case, the modulus of elasticity of the material of the coating 6 is preferably at least 10 kN / mm ² greater than the elasticity modulus of the material of the base body 5, but the difference between the moduli of elasticity of the materials used is preferably considerably greater. The coating 6 has a thickness in a range of 0.5 to 5 mm, preferably 0.8 to 4.5 mm. Preferably, the coating 6 is applied to the entire circumference of the main journal 2 and the Pleuellagerzap ^¬ fens 3 in the same thickness.

In the embodiment shown in Fig. 2, only the main bearing pin 2 is shown with the coating 6, but it would of course also possible to provide only the connecting rod journal 3 or both the main bearing pin 2 and the connecting rod journal 3 with the coating 6. A coating 6 provided on the entire surface of the base body 5 or a coating of individual main bearing journals 2 and / or connecting rod journals 3 is also conceivable.

Furthermore, in the embodiment shown in FIG. 2, the coating 6 is provided on both radii 7 that merge into the respective crank arm 4 from the main journal 2. The

Coatings 6 in the region of the radii 7 contribute to the supporting effect and thus to increasing the flexural rigidity of the crankshaft 1. In this case, the coating 6 is preferably also provided on the respective crank web 4 up to a height of approximately 50%, ie a certain part of the crank web 4 is also provided with the coating 6. The material of the coating 6 may be a metal selected from the group consisting of tungsten, cobalt, molybdenum, beryllium, aluminum, titanium, iron or alloys comprising at least one of these materials. The use of a metallic material for the

Coating 6 enables driving of which later some are described particularly simple Herstellungsver ^¬. Alternatively, the material of the coating 6 may be a ceramic material selected from the group consisting of aluminum nitride, aluminum oxide, silicon carbide, silicon nitride ^¬, tungsten carbide and boron carbide. The base body 5 is in the present case at least partially ^¬ , preferably completely, made of an iron or aluminum ^¬ umwerkstoff.

FIG. 3 shows a step of a method for producing the crankshaft 1. In a first step, the main body 5 is made of a metallic material by means of a per se known method, such as casting or forging, wherein the use of a cast base body 5 for the crankshaft 1 causes an acoustic damping. Preferred casting materials may be EN-GJS-500-7, EN-GJS-600-3, ENGJS-700-2, EN-GJS-800-2, or even austempered ductile iron (ADI) castings such as GJS-800 -8, GJS-1000-5, GJS-1200-2 or GJS-1400-1. In contrast, a forged crankshaft has better fatigue properties and a higher modulus of elasticity. In the illustrated second step, the coating 6 is applied to the base body 5, in particular to at least one of the main bearing journals 2 and / or to at least one of the connecting rod journals 3. brought. For this purpose, an application device 8 is provided in the present case, which applies a designated by the reference numeral 9 beam on the base body 5, which forms the coating 6. The coating 6 can be applied, for example, by means of thermal spraying, high-speed flame spraying, melt thickening, plasma coating or laser remelting. By means of the arrow indicated a Rota ^¬ tion of the crankshaft 1 in Fig. 3, but it is also possible to pivot the coating jet or move around a device for outputting the coating 6 to the crankshaft 1.

One way of producing the coating 6 is to apply it by thermal spraying. Here, for example, a wire or powder coating material is melted in a gas flame, an arc or a plasma, atomized by a gas jet and thrown onto the base body 5 at high speed. By adhesive Se ^¬ kundärbindungen results in an adhesion of the material of the coating 6 on the base body 5, wherein, especially in a corresponding preheating of the main body 5, and primary binding interactions can be present. Not only the abovementioned metallic materials but also the above-mentioned ceramic materials can be applied to the base body 5 by means of thermal spraying. At the

Plasma spraying particularly good coating results and correspondingly high-quality surfaces of the coating 6 can be obtained when the base body 5 is heated and the coating process is carried out in a suitable chamber in an inert gas atmosphere. Such an approach results in a low oxide content and, ideally, to a complete oxide-free, egg ^¬ ner low porosity and a high adhesion of the coating. 6 In the case of the high velocity flame spraying, which is also suitable for applying the coating 6 and which is also a variant of normal flame spraying, powdery coating materials are applied to the base body 5 at very high speed. In this case, an unillustrated, a combustion chamber exhibiting burner is provided, which can leak a gaseous or liquid fuel gas-oxygen flame supersonic ^¬ speed and produces a tight-fitting, dense and equally low-pored coating 6, which also has low internal stresses and therefore in a very large ^¬ SEN thickness can be applied to the base body. 5 By the high velocity gas mixture leaving the powder particles are accelerated and meet with high kinetic energy but a relatively low temperature on the surface of the base body 5, whereby the particles are strongly abge ^¬ flattens. The relatively low temperature of the particles, the coating 6 is a predictable chemical together ^¬ mensetzung on, is changed only slightly metallurgically, is nearly homogeneous, and has a fine-grained structure. This

Process is characterized by its high efficiency in a special way.

In melt atomization, also known as the Osprey process, a liquid metal jet is atomized by an inert gas and the coating 6 is formed utilizing the kinetic energy and heat content of the particles. The hot particles compact when hitting the base body 5 of the crankshaft 1 and thus form the coating. 6

In the plasma coating process, the coating 6 is extracted from a plasma by the action of an electrical voltage, and the base body 5 is coated with the coating 6 overdrawn. For this purpose, the main body 5 is introduced into a vacuum chamber. After the evacuation of the chamber, a working gas, usually argon, is introduced into the same and by entry of energy, for example by electrical discharge, microwaves or high frequency, a low-pressure plasma is ignited. After the introduction of the working gas other gases, example ^¬ as methane, acetylene or nitrogen can be introduced into the chamber. In the chamber, the coating material, for example ^¬ a metal or a metal-containing compound, at temperatures in a range of preferably 200 - 500 ° C atomized and it is reflected as the coating 6 on the Ma ^¬ material of the main body 5 down.

The material of the coating 6 can also be treated with a laser, in particular with a CO 2 laser, during the course of the coating process. Here, the Be ^¬ coating 6 can be supplied, for example in powder or paste form in a single step process via a nozzle in the laser beam generated by the molten bath or applied in a two step process by plasma spraying and post-treated with the laser beam. For this purpose, especially ceramic materials are well suited. If the material of the coating 6 is applied in paste form and coated with the laser beam onto the main body 5 of the crankshaft 1, inhomogeneous material mixtures can also be processed. The power and the travel speed of the laser can vary depending on the material used for the coating 6 and the material of the main body 5 of the crankshaft 1. A particular advantage when using a laser beam for applying the coating 6 is the low heat load of the crankshaft 1 and the locally narrowly limited action of the laser beam. In order to ensure a sufficiently good adhesion of the coating 6 on the main body 5, cleaning of the surface of the main body 5 may be expedient before carrying out each of the coating methods explained above. Such cleaning can be carried out by procedures known from the general state of the art. In addition, determined the surface to be treated activating and / or pre-treatments haftverbesserende the surface of Grundkör ^¬ pers 5 can be made.

Fig. 4 shows the example of a cantilevered and acted upon by a force F shaft, which is representative of the crankshaft 1, the effectiveness of the coating 6. Here, the base body 5 has a radius r and is provided with the coating 6, the has a thickness d. Including the coating 6, the shaft thus has the radius R, which thus results from the sum r + d. In a non-coated ^¬ shaft results in the bending stiffness of B = E i · I g _it = E i · n / 4 · R ^4, wherein

Ei = modulus of elasticity of the material of the shaft

Ig _es = total area moment of inertia

R = outer radius

In the illustrated in Fig. 4, provided with the coating 6 shaft having the same radius R as the uncoated shaft, the flexural rigidity results

B = E i * I i + E ₂ * I ₂ = E i * n / 4 * r ⁴ + E ₂ * n / 4 * (R ⁴ -r ⁴ ), where Ei = modulus of elasticity of the material of the main body 5 Ii = area moment of inertia of the main body 5 E ₂ = modulus of elasticity of the material of the coating 6 ± 2 = area moment of inertia of the coating 6 r = radius of the main body 5

R = radius of the main body 5 + thickness of the coating 6

By way of example some ver for the coating 6 ^¬ reversible materials and their material properties modulus of elasticity and density as well as relevant for the choice of material Ver ^¬ ratios between modulus of elasticity and density are listed below:

Material Modulus of elasticity Density p in E / p E / p

E in kN / mm ² kg / m ³

Tungsten 411 19300 21.3 1.1

Cobalt 209 8900 23.5 2, 6

WC-10% Co 570 14500 39, 3 2,7

Molybdenum 330 10300 32, 0 3.1

Steel 210 7800 26, 9 3,5

Aluminum 70 2700 25, 9 9, 6

Silicon 150 2330 64, 4 27, 6

Aluminum nitride 300 3200 93, 8 29, 3

Silicon nitride 170 2400 70.8 29, 5

Alumina 400 3500 114.3 32, 7

Silicon carbide 400 3100 129, 0 41, 6

Boron carbide 450 2400 187.5 78.1 The following values result for the use of tungsten for the coating 6 of a crankshaft 1 comprising a main body 5 consisting of a steel material:

In this case, therefore, the main body 5 had a modulus of elasticity of 210 kN / mm ² and a density of 7800 kg / m ³ and the coating 6 a modulus of elasticity of 400 kN / mm ² and a density of 19000 kg / m ³ . It can be seen that while the use of tungsten for the coating 6, although the mass of the crankshaft 1 increases, the increase in the flexural rigidity is greater than that of ^¬ the mass. The following values result for the use of silicon carbide for the coating 6 of a crankshaft 1 comprising a main body 5 consisting of a steel material: Connecting rod journal: R = 27 mm

Layer thickness d flexural stiffness mass increase in%

increase in%

0.5 8.2 -2.2

1 16, 0 -4.3

2 30.3 -8.4

4 54, 1 -16, 2

Main journals: R = 33.5 mm

Layer thickness d flexural stiffness mass increase in%

increase in%

0.5 6.7 -1.7

1 13, 0 -3.5

2 24, 9 -6, 8

4 45, 6 -13.2

In this case, the main body 5 again had a modulus of elasticity of 210 kN / mm ² and a density of 7800 kg / m ³ , where ^¬ the coating 6 has a modulus of elasticity of 450 kN / mm ² and a density of 3200 kg / m ³ had. For the use of silicon carbide results in a very large increase in the bending stiffness even a decrease in mass, since silicon ^¬ carbide has a lower density than the steel material used in this case for the main body 5.

For the use of tungsten carbide (WC-10% Co) for loading ^¬ coating 6 of a group consisting of a steel material base body 5 having the crank shaft 1 results in the following values: Connecting rod journal: R = 27 mm

Layer thickness d flexural stiffness mass increase in%

increase in%

0.5 12, 3 3.2

1 24,0 6, 2

2 45.3 12, 3

4 80, 9 23, 6

Main journals: R = 33.5 mm

Layer thickness d flexural stiffness mass increase in%

increase in%

0.5 10.0 2.5

1 19, 5 5.1

2 37, 3 10.0

4 68, 2 19, 3

In this case, the main body 5 again had a modulus of elasticity of 210 kN / mm ² and a density of 7800 kg / m ³ , where ^¬ the coating 6 has a modulus of elasticity of 569 kN / mm ² and a density of 14,500 kg / m ³ had. It follows that WC-10% Co is very suitable as a material for coating Be ^¬ 6th

From the above tables it is also clear that the thickness d of the coating 6 has a significant influence on the increase in the flexural rigidity of the main journal 2, the Pleu ^¬ ellagerzapfens 3 and the radius 7 and thus the entire Kur ^¬ belwelle 1 has.

5 shows a possibility of applying the coating 6 to a radius 7 passing from one of the main bearing journals 2 into one of the crank webs 4. compared to the outer contour of the crankshaft 1 in this embodiment, only in the radial direction recessed Vertie ^¬ tion 10, which can be produced with known means, for example by machining or even during forging or casting of the crankshaft 1 can be produced. The recess 10 is also filled in the coating of the crankshaft 1 with the material of the coating 6 in order to provide the radius 7 with the coating 6. In the present case, the recess 10 is filled to such a height with the material of the coating 6, that the coating 6 is set back relative to the peripheral surface of the main journal 2 by a certain amount and thus are not processed in the mechanical Bear ^¬ processing of the main journal 2 what must be a significant cost savings.

In the embodiment of FIG. 6, the recess 10 of the radius 7 is set back in addition to the rearward offset in the radial direction in the axial direction relative to the outer contour of the crankshaft 1, so that there is an undercut not only in the radial direction but also in the axial direction what letztend ^¬ Lich performs the larger amount of the coating 6 to an additional increase in stiffness. The recess 10 is again filled with the material of the coating 6, wherein the coating both with respect to the circumferential surface 6 of the main bearing journal 2 and is also set back to a Planflä ^¬ surface of the crank arm. 4

In principle, it would also be possible to return the depression 10 only in the axial direction with respect to the outer contour of the crankshaft 1. Optionally, the ^{backsetting of} the coating 6 with respect to the main bearing journal 2 or the crank web 4 can also be dispensed with. In Figures 5 and 6 is the radius le ^¬ diglich 7 between the main bearing journals 2 and the Crank cheek 4 shown, it is obvious, however, that the described embodiments can be applied analogously for each of the provided between the connecting rod journal 3 and the crank arm 4 radius 7. In FIGS. 5 and 6, only the radius 7 is provided with the coating 6, ie the main bearing journals 2, the connecting-rod journals 3 and the crank cheeks 4 are not provided with the coating 6. Of course, it would also be possible, in the case of a likewise provided coating of the main bearing journal 2, the connecting rod journal 3 and / or the crank webs 4 to provide the radii 7 with the described and illustrated undercuts or recesses 10.

FIGS. 7 and 8 show further possible radii, which can be provided with the coating 6 with reference to FIGS. 5 and 6, but in principle also with reference to the types described in FIG. Thus, in FIG. 7, the so-called flange end of the crankshaft 1 is shown, which in a manner known per se has a flange 11 to which, for example, a flywheel, a vibration damper or the like can be attached. Between the one end of the crankshaft 1 forming flange 11 and the first or on this side outermost crank arm 4 is a subsequently referred to as Flanschla ^¬ gerzapfen 2a main journal 2 is provided. See intermediate the flange 11 and the Flanschlagerzapfen 2a and between the Flanschlagerzapfen 2a and the crank arm 4 respective radii 7 are provided on the with reference to the Figures 5 and 6 or with reference to FIG. 2-described ^¬ ne manner with the coating 6 can be provided, ie it can be deposited radii 7 according to FIGS. 5 and 6 or tangential radii 7 according to FIG. 2. Fig. 8 shows the so-called pin end of the crankshaft 1, wel ^¬ ches than the flange 11 opposite completion of the crankshaft 1 has a pin 12, the z. B. can be connected in a conventional manner with the valve train equipped with the crankshaft 1 th internal combustion engine. Between the pin 12 and the outermost on this side crank arm 4 is a hereinafter referred to as journal bearing 2b 2b Hauptlagerzap ^¬ fen 2 is provided, as well as the flange bearing pin 2a in the manner described above analogous to the other main bearing pin 2 in the crankcase of Internal combustion engine gela ^¬ Gert is. Furthermore closes 2b referred to as support bearing ^¬ tap 2c designated main bearing journal 2 to the pin 12 at the opposite side of the pivot bearing pin. At the transition of the pin 12 in the journal bearing journals 2b and at the transition of the journal bearing pin 2b in the crank arm 4 and also at the transition of the pin 12 in the support journals 2c respective radii 7 are provided which provided in the manner with the coating 6 can be as described in Figures 5 and 6 or as described in Fig. 2 is ben. On the support journals 2c may optionally be omitted. Depending on the type of load on the crankshaft 1, which can be influenced, inter alia, by the flywheel, the vibration damper and / or the valve train, it is in principle possible to apply only one of the plurality of wheels 7 of the crankshaft 1 to one of the crankshaft 1 Types described above to be provided with the coating 6. Of course, certain combinations of radii 7 can be provided with the coating 6. This is true depending on the expected during operation load of the crankshaft 1 in principle for all possible combinations of the possibilities described herein of the application of the coating 6 to stiffen the crankshaft 1 at the desired location or at the desired locations. In a manner not shown, the crankshaft 1 also have a toothing, in particular for connection to the valve train, which is located on the pin 12, on the

Flange journal 2a and / or may be located at another suitable location of the crankshaft 1. Furthermore, the crankshaft 1 can have more than one flange journal 2a, more than one journal journal 2b and / or more than the one

Support journal 2c have. In addition, these need not necessarily be cylindrical, but may also have a truncated cone shape or the like. For example, it may be sufficient if only the radii 7 in the region of the flange bearing journal 2a and / or radii 7 in the region of the journal bearing journal 2b and / or radii 7 in the area of Stützlagerzap ^¬ fens 2c provided with the coating 6 to the deformation of the respective End of the crankshaft 1 to reduce and thereby reduce a wobble occurring during operation of attachments of the crankshaft 1. This would also reduce the additional, introduced from the wobbling movement of the attachments on the crankshaft 1 stresses. Of course, the coating of these radii 7, also referred to as flange and journal radii, in the region of the flange bearing journal 2a and / or radii 7 in the area of the journal bearing journal 2b and / or radii 7 in the region of the support journal 2c can also be carried out by coating the other, if necessary Radii 7 and the running surfaces of the optionally to be coated main journal 2 and connecting rod trunnions 3 done.

Since, as explained above, the flange bearing journal 2a, the journal bearing journal 2b and the supporting journal 2c also constitute main bearing journals 2, these, if appropriate also exclusively these or one of these, can of course be provided with the coating 6. Therefore, everything applies to the main bearing journals 2 with regard to the coating 6 and the design of the radii 7 also stated for the Flanschlagerzap- 2a, the journal bearing journal 2b and the support journal 2c. Furthermore, it is also possible to provide the flange 11 and / or the pin 12 with the coating. It is also possible to provide a not shown toothing of the crankshaft 1 with the coating 6. Optionally, only the toothing can be provided with the coating 6. FIGS. 9 and 10 show ways of attaching one or more oil bores 13 to a main bearing journal 2 or a connecting rod journal 3 of the crankshaft 1. The Fi ^¬ gures 9 and 10 show the main bearing pin 2, the following, however, applies analogously to the connecting rod journal 3. The oil holes 13 in a conventional manner, the oil supply of the connecting rod bearings and possibly also the crankshaft bearing safely.

According to the embodiment shown in FIG. 9, the oil hole 13 is introduced into the main bearing journal 2 and / or into the connecting rod journal 3 before the coating is applied. This generating the oil hole 13 can be done in a conventional manner with a drill or the like. During the application of the coating 6, the oil bore 13 is held closed in such a way that the material of the coating 6 can not penetrate into the oil bore 13. In the present case, two closing elements 14 are provided for this purpose, which are inserted into both ends of the oil hole 13 and remain in the oil hole 13 during the application of the coating 6. After applying the coating 6, the two closing elements 14 can be removed to release the oil hole 13. Depending on the material of the coating 6, the material of the closing elements 14 and possibly other factors the closure elements 14 are removed in different ways, some of which are described below. The closing elements 14 are conical in the present case, so that they remain in the oil hole 13 during the application of the coating 6, whereby a cylindrical design of the closing elements 14 is possible. Furthermore, it can be seen that the closing elements 14 protrude beyond the thickness of the coating 6, so that they can be easily removed. Of course, however, the closing elements 14 can also have a smaller height than the thickness of the coating 6 so ^¬ that they are located wholly within the coating. 6

It may be possible to remove the closing elements 14 after solidification of the coating 6 by simply pulling them out of the bore 01, but it would also be conceivable to remove the closing elements 14 by drilling out. In the case of extraction of the closure members 14, they should be thicker than the coating 6 to protrude therefrom. In the case of boring, it may be advantageous to choose the height of the closure elements 14 so that they are completely covered by the coating 6, so that not the entire Be ^¬ coating 6 must be pierced. In the present case, the closing elements 14 are designed in the manner of plugs and may consist of an almost arbitrary material which is not destroyed by the high temperatures which may occur during the application of the coating 6. The closure elements 14 may be made of a suitable material, such as a plastic or rubber, which ensures that in the interface between the coating 6 and the respective closing element 14 no adhesive

Binding arises. However, existing closing elements 14 are also conceivable, for example from metal ^¬ metallic materials. If necessary, the closing elements 14 from a Produce material that can not be processed by drilling, or to avoid any occurring due to drilling damage to the coating 6, it is also conceivable to remove the closing elements 14 by eroding from the oil hole 13. Furthermore, the closing elements 14 could also consist of such a material which evaporates, burns or dissolves in a similar manner during the application of the coating 6 in order to be able to dispense with the step of removing the closing elements 14. For example, this could be a suitable foam. In this

However, it would have to be ensured that the closing ^elements 14 remain in the oil hole 13 until the coating 6 has solidified and can no longer change its state or can no longer expand. It is preferable if the locking elements 14 do not project beyond the thickness of the Be ^¬ coating. 6 Another possibility could be that in this case, made of a magnetic material, particularly a suitable metal Verschließele ^¬ elements 14 by means of a magnet, in particular Neten a electromagnets to hold in the oil hole 13 and immediately before the solidification of the material of Remove coating 6 from the oil hole 13. In this way, the dismantling can be done inexpensively under serial conditions, in particular automated. It is preferable if the closing elements 14 project beyond the thickness of the coating 6.

An alternative way of producing the oil hole 13 is shown in FIG. Here, the oil hole 13 is introduced after the application of the coating 6 in the main bearing journal 2 and / or in the connecting rod journal 3. This can be done with the drilling tools 15 shown in FIG. 10, wherein in the present case two drilling tools 15 are provided in order to prevent damage to the coating 6 by the Austre. th of the drilling tool 15 to prevent. It is also possible to introduce the oil bore 13 by means of die sinking, preferably CNC-controlled or automated, into the crankshaft 1, if this is necessary on account of the material, the coating 6, in particular the high hardness or strength thereof. Subsequent to the EDM can be drilled from one side "residual" oil hole 13 conventionally. When the Win ^¬ angle is pointed to for the EDM, the coating may be radially erodes or it may be a cranked electrode can be used.

In one embodiment, not shown, it would also be possible to introduce the oil hole 13 before applying the coating 6 in the crankshaft 1 and after applying the coating 6 only through the coating 6 to drill the existing oil hole 13 or the Remove coating 6 to the oil hole 13 in another way. A possibly in this process in the oil hole 13 Gera ^¬ tend material of the coating could also be removed in this course. If there are interfering contours, the one

Drilling under a certain angle complicate or prevent such a drilling process could also be at an angle of up to 90 ° tangentially and axially relative to the peripheral surface of the main bearing journal 2 and the connecting rod journal 3. Furthermore, if the angle for tapping is too acute, the coating 6 can be drilled in the radial direction. Following this, the "remaining" oil hole 13 can be conventionally drilled from the other side at the required angle.

Claims

P a n t a n s p r e c h e

Crankshaft having a base body of a metallic material, which has at least two main journal and wenigs ^¬ least one connecting rod journal and a plurality of radii, characterized in that

at least one of the main bearing journals (2, 2a, 2b, 2c) and / or one of the connecting rod journal (3) and / or one of the radii (7) has a coating (6) of a material, wel ^¬ ches a higher modulus of elasticity than the material of the main body (5) of the crankshaft (1).

Crankshaft according to claim 1,

d a d u r c h e c e n c i n e s that

the coating (6) has a thickness in a range of 0.5 to 5 mm, preferably 0,

8 to 4.5 mm, more preferably 0,

9 to 4.0 mm, most preferably 1.0 to 3.5 mm.

Crankshaft according to claim 1 or 2,

d a d u r c h e c e n c i n e s that

a plurality of main bearing journals (2, 2a, 2b, 2c) and / or connecting rod journal (3) and / or radii (7) have the coating (6).

Crankshaft according to claim 1, 2 or 3,

d a d u r c h e c e n c i n e s that

the coating (6) on at least one of one of

Main journal (2, 2a, 2b, 2c) and / or connecting rod journal (3) in a crank arm (4) passing radius (7) and / or on a journal bearing journal (2b) and / or on a flange bearing pin (2a) and / or on a support journal (2a) provided radius (7) is provided. Crankshaft according to claim 4,

d a d u r c h e c e n c i n e s that

the radius (7) has a recess (10) recessed in the radial and / or axial direction with respect to the outer contour of the crankshaft (1), which recess is at least approximately filled with the material of the coating (6).

Crankshaft according to claim 5,

d a d u r c h e c e n c i n e s that

the recess (10) in such a way with the material of the coating

(6) is filled, that the coating (6) with respect to a circumferential surface of an adjacent main journal

(2, 2a, 2b, 2c) or Pleuellagerzapfens (3) and / or a plane surface of an adjacent crank arm (4) is set back.

Crankshaft according to one of claims 1 to 6,

d a d u r c h e c e n c i n e s that

the material of the coating (6) is a metal selected from the group consisting of tungsten, cobalt, Molyb ^¬ dän, beryllium, aluminum, titanium, iron, or alloys having at least one of these materials.

Crankshaft according to one of claims 1 to 6,

d a d u r c h e c e n c i n e s that

the material of the coating (6) is a ceramic material selected from the group consisting of aluminum ^¬ nitride, alumina, silicon carbide, silicon nitride, boron carbide and Wolf ^¬ ramkarbid.

Crankshaft according to one of claims 1 to 8,

characterized in that the base body (5) consists at least partially, preferably fully ^¬ constantly, of an iron or aluminum material.

10. Crankshaft according to one of claims 1 to 9,

d a d u r c h e c e n c i n e s that

the modulus of elasticity of the material of the coating (6) is at least 10 kN / mm ^2, preferably 30 kN / mm ^2, more Favor ^¬ ter, is greater than 50 kN / mm ^{2 and} the modulus of elasticity Mate ^¬ rials of the base body (5).

11. Crankshaft according to one of claims 1 to 10,

d a d u r c h e c e n c i n e s that

the crankshaft (1) is made by forging.

12. A method for producing a crankshaft, wherein in a first step, a base body made of a metallic material which at least two main bearing ^¬ tap and at least one connecting rod journal and a plurality of radii,

d a d u r c h e c e n c i n e s that

on at least one of the main journal (2, 2a, 2b, 2c) and / or one of the connecting rod journal (3) and / or one of the radii (7) a coating (6) made of a material is applied, which has a higher modulus of elasticity than the base material of the main body (5).

13. The method according to claim 12,

d a d u r c h e c e n c i n e s that

the coating (6) by means of thermal spraying, high-speed flame spraying, atomizing from the melt,

Plasma coatings or laser remelting is applied.

14. The method according to claim 12 or 13, characterized in that prior to the application of the coating (6) at least one oil hole (13) in at least one of the main bearing journals

(2, 2a, 2b, 2c) and / or in at least one of the connecting rod journal (3) is introduced, and that the oil bore (13) during the application of the coating (6) is held such ^¬ closed, that the material of the coating

(6) does not penetrate into the oil hole (13).

Method according to claim 12 or 13,

d a d u r c h e c e n c i n e s that

after applying the coating (6) in at least one of the main bearing journals (2, 2a, 2b, 2c) and / or in at least one of the connecting rod journal (3) an oil hole (13) is introduced.