Low-wear toothing arrangement for load transmission

Abstract

The invention relates to a toothing arrangement for load transmission, having a first tooth (22) for introducing a load and a second tooth, which can be supported on a support surface (24) on the first tooth (22), for discharging the load, wherein the first tooth (22) and / or the second tooth is / are produced from an oil-free, self-lubricating sintered material (26), wherein the sintered material (26) has an open-pore metal matrix in which solid lubricant particles and carbon particles are dispersed. By means of the solid lubricant particles in the hard sintered metal matrix of the sintered material (26) that remain unused during sintering thanks to the carbon, oil-free, self-lubricating solid lubrication can be achieved which can withstand heavy loads, thus enabling a toothing arrangement lubricated with low wear.

Description

[0001] FLENDER GMBH Düsseldorf, November 12, 2025 Our reference: FD 45856 / GR 2024P04760EP

[0002] Flender GmbH

[0003] Alfred-Flender-Str. 77, 46395 Bocholt, Germany

[0004] Low-wear gear arrangement for load transmission

[0005] Description

[0006] The invention relates to a gear arrangement by means of which static and / or dynamic load transmission can be effected, as well as to such a transmission, such a gear coupling, and such uses. The invention further relates to a method for manufacturing such a gear arrangement and to a data agglomerate for the virtual representation of such a gear arrangement for the purpose of additive manufacturing and / or simulation.

[0007] WO 2015 / 135832 Al shows a tooth coupling with load-transmitting teeth, in which the respective toothing has an internal toothing and an external toothing meshed with the internal toothing to transmit the load.

[0008] It is known to lubricate gear couplings with lubricating oil or grease.

[0009] It is known to add particulate solid lubricants, such as graphite or M0S2, to liquid lubricants, for example lubricating oil, in order to improve the lubricating properties and reduce the friction between the lubricated friction partners.

[0010] From Sprogies, N.; Löhner, T.; Stahl, K. “Improved Operating Behavior of Self-Lubricating Rolling-Sliding Contacts under High Load with Oil-Impregnated Porous Sinter Material” Lubricants 2024, 12, 259. https: / / doi.org / 10.3390 / lubricatorsl2070259 it is known that discs made of a case-hardened P-FL-05M1 sintered material impregnated with lubricating oil, which has an addition of 2% molybdenum disulfide (M0S2) and tungsten sulfide (WS2) as solid lubricant additives in the powder mixture, rolling against each other at a relative speed of 8 m / s, exhibit a Hertzian contact pressure of 1043 N / mm². 2 and 1,200 N / mm 2 Achieve low coefficients of friction.

[0011] From De Lima, GA; Klein, AN; Furlan, KP “Controlling the Solid-State Reaction in Fe-MoS2 Self-Lubricating Composites for Optimized Tribological Properties” Lubricants 2022, 10, 142. https: / / doi.org / 10.3390 / lubricantsl0070142, a self-lubricating, iron-based composite material containing Fe-MoS2 and graphite, produced by powder metallurgy and low-temperature sintering, is known, achieving a low coefficient of friction and a low wear rate.

[0012] There is a constant need to reduce wear in a gear assembly.

[0013] The object of the invention is to demonstrate measures that enable a low-wear gear arrangement.

[0014] The problem is solved by a gear arrangement with the features of claim 1, a use with the features of claim 8, a method with the features of claim 11, a transmission with the features of claim 12, a gear coupling with the features of claim 14, and a data agglomerate with the features of claim 15. Preferred embodiments are specified in the dependent claims and the following description, each of which, individually or in combination, may represent an aspect of the invention, the scope of protection being determined by the claims. When a feature is presented in combination with another feature, this serves only to simplify the presentation of the invention and is in no way intended to imply that this feature cannot also constitute a further development of the invention without the other feature.

[0015] One aspect of the invention relates to a gear arrangement for load transmission, comprising a first tooth for introducing a load and a second tooth, which can be supported on a bearing surface against the first tooth, for discharging the load, wherein the first tooth and / or the second tooth is made of an oil-free, self-lubricating sintered material. The sintered material has an open-pore metal matrix. Solid lubricant particles and carbon particles are dispersed in the metal matrix. In particular, the first tooth is made of the sintered material and the second tooth of a steel, or the second tooth is made of the sintered material and the first tooth of a steel.

[0016] It was recognized that in a gear arrangement, it is possible to provide solid lubrication instead of oil or grease lubrication by using a sintered material with an open-pore metal matrix for at least one of the gear teeth, in which solid lubricant particles and carbon particles are dispersed. It is actually expected that at a typical sintering temperature of 1150°C, the solid lubricant particles dispersed in the metal matrix of the sintered material would decompose and / or bond with the metal particles of the matrix, resulting in the solid lubricant particles being so strongly bound in the metal matrix that they can no longer perform their friction-reducing function.With the solid lubricant molybdenum disulfide (M0S2), FeS would form in an iron (Fe) metal matrix at temperatures as low as 775°C, meaning that no M0S2 would remain as a solid lubricant after sintering. However, it was discovered that the carbon in the green body allows the carbon to interact with the metal matrix more quickly during sintering than the solid lubricant M0S2. Therefore, the presence of carbon prevents or at least reduces the consumption of M0S2 during sintering. This allows for an open-pored metal matrix after sintering, through which the solid lubricant remaining in the metal matrix can rise to the surface to provide friction-reducing lubrication. If the carbon contained in an open pore burns off during sintering, this allows the solid lubricant intended to be present below the burned-off carbon to rise to the surface.If unburned carbon, particularly graphite, remains in the pore between the solid lubricant and the surface, it can be forced out of the pore during operation and also act as a solid lubricant, thus reducing friction. Furthermore, the chemical behavior of the carbon within the metal matrix can be influenced by the sintering temperature. This ensures sufficient strength and hardness for the sintered material and, through the sufficiently mobile carbon within the metal matrix and the solid lubricant not consumed during sintering, achieves adequate self-lubrication without the need for additional lubricating oil or grease.Surprisingly, the sintering temperature can be in a temperature range significantly below the usual sintering temperatures of 1150°C, in which, without the carbon, consumption of the solid lubricant would occur, but by adding sufficient carbon over the sintering time, consumption of the solid lubricant in the metal matrix can be kept sufficiently low to produce a solid, self-lubricating sintered material.

[0017] It was also recognized that in a gear arrangement, there are typically applications where the strength achieved by the sintered material for one gear tooth, when supported by a load-bearing component (e.g., made of steel), results in a low-wear material pairing even under dynamic loads. It is assumed that the tooth made of the sintered material can withstand very high loads and, due to its self-lubricating effect with the help of solid lubricant particles and, if applicable, carbon particles, provides maintenance-free lubrication, but exhibits a rather brittle material behavior. In contrast, the tooth of the other gear tooth, particularly one made of steel and interacting via the bearing surface, can exhibit a significantly more ductile material behavior.This allows the steel tooth to absorb torque shocks to a particularly high degree through elastic deformation, while the sintered tooth ensures oil-free and grease-free lubrication between the teeth. The surface pressure occurring in the Ab support surface allows the solid lubricant to be pressed against the surface of the sintered material. The surface pressures expected in a gear arrangement should be high enough for the solid lubricant to grip and / or clamp onto the irregularities of the existing surface roughness. This allows relative movement of the pressed Ab support surfaces of the teeth, caused, for example, by elastic deformation, to occur more easily and with less wear, thanks to a lower coefficient of friction.If a solid lubricant particle should detach from the metal matrix of the sintered material, it is possible to press this solid lubricant particle back onto the sintered material in the area of ​​the bearing surface. However, it is also possible that the solid lubricant particle detached from the sintered material is pressed onto the bearing surface of the other tooth, thereby gradually coating the tooth not made of the sintered material, so that the other tooth can also acquire a friction-reducing surface, at least in some areas. Abrasion of the sintered material can even lead to an additional friction-reducing lubricating effect due to the pressed-on solid lubricant. Furthermore, cold welding in the area of ​​the bearing surfaces of the pressed teeth is not expected under the anticipated operating conditions of the gear arrangement.The unused solid lubricant particles in the hard sintered metal matrix of the sintered material, achieved with the help of carbon during sintering, allow for a high-load-resistant, oil-free and self-lubricating solid lubrication, thus enabling a low-wear lubricated gear arrangement.

[0018] The gear arrangement establishes a meshing connection between two separately designed gear teeth by having at least one first tooth of the first gear tooth press against the tooth flank of at least one second tooth of the second gear tooth via a tooth flank to transmit or support a load. In this gear arrangement, for example, two gears can form a spur gear, an internal gear can mesh with an external gear, or a pinion can interact with a rack. The first and second gear teeth can perform a relative motion with each other, in which the first tooth rolls on the second tooth, and a subsequent first tooth rolls on the subsequent second tooth, and so on.However, it is also possible that in the gear arrangement the gear partners are stationary relative to each other and primarily only support static loads, whereby the static loads can change in magnitude, which can result in slight relative movements of the pressed Ab support surfaces of the teeth due to elastic deformations of the teeth under the applied load.

[0019] The first and second teeth can be based on an involute gear tooth, possibly with a flank correction to modify the involute gear tooth pattern. However, other gear tooth designs are also possible.

[0020] The bearing surface is a surface area of ​​the first tooth and / or the second tooth where the teeth are pressed against each other during load transmission. Typically, the bearing surface is located exclusively on the tooth flanks. If the gear arrangement is designed for only one load direction, it is even possible for only one tooth flank to be used as the bearing surface. Preferably, either only the first tooth (at least one) or only the second tooth (at least one) is made of the sintered material, thus making it possible to apply the sintered material to only one of the gear teeth in the gear arrangement, thereby minimizing the manufacturing effort for the gear arrangement.

[0021] The solid lubricant particles result in a lower coefficient of friction between the first and second teeth in the bearing surface area compared to the coefficient of friction at the same location without the solid lubricant. Typically, the solid lubricant has a layered structure similar to graphite and / or a plate-like structure similar to PTFE. The solid lubricant can be formed using molybdenum, particularly as M0S2, MoO2, or MoOs, although other solid lubricants are also possible.

[0022] The carbon, added primarily as graphite, has a positive effect on delaying the reaction of M0S2 with the metal matrix, particularly the iron-based matrix. The addition of carbon increases the temperature at which all the M0S2 is consumed to form Fe or Fe-Mo sulfides, which are not solid lubricants. Furthermore, the carbon addition increases the hardness of the metal matrix, which also contributes to the good tribological properties.

[0023] The sintered material can be produced from a sintered green body consisting of a powder mixture containing metal particles, solid lubricant particles, and carbon particles. For optimal results with the sintered material, the powder mixture depends not only on the mixing ratios (e.g., in volume percent) but also on the particle size. In particular, when carbon is added as graphite, an interaction between the graphite type, the graphite content, and the sintering temperature is assumed.

[0024] Good results for the sintering material can be achieved, for example, with a powder mixture containing 9 volume% M0S2 and 2.5 volume% graphite with an initial graphite particle size of 32 pm, sintered at 825°C, as well as with a powder mixture containing 9 volume% M0S2 and 2.5 volume% graphite with an initial graphite particle size of 5.9 pm, sintered at 850°C. M0S2 is preferably present in the sintering material at more than 5 volume%, typically less than 9 volume%. More than 7 volume% or even more than 7.5 volume% M0S2 can also be used. The remainder of the powder mixture can consist of iron, with impurities in the powder mixture generally being less than 1 volume%. For example, copper is typically present at less than 1 volume%. In some cases, nickel is present at less than 1 volume%. It is preferred that the sintering material is copper-free.The sintered materials produced in this way can have an average coefficient of friction of approximately 0.07 and an average wear rate of approximately 7 x 10. 6 mm 3 N 1 m 1 or approximately 5 x 10 6 mm 3 N 1 m 1 These sintered materials exhibit excellent tribological behavior in both nitrogen and atmospheric environments.

[0025] The operating conditions in the gear arrangement lead in particular to a maximum surface pressure p, which occurs, for example, during torque surges. ma x in the support area of ​​400 N / mm 2 < p ma x < 900 N / mm 2 , in particular

[0026] 500 N / mm 2 < p max < 700 N / mm 2 , while preferably in regular normal operation a surface pressure p of 150 N / mm² 2 < p < 400 N / mm 2 , in particular

[0027] p = 300 N / mm 2 ± 50 N / mm 2 prevails. Due to heat generation in the area of ​​the gear arrangement, under the operating conditions, a temperature T in the area of ​​the support surface of 20°C < T < 80°C, preferably 23°C < T < 50°C and particularly preferably 25°C < T < 30°C is assumed.

[0028] In particular, it is provided that in a powder mixture for the production of a green body for the sintered material, the solid lubricant particles have a volume fraction VF of 7.5% < VF < 10.5%, in particular VF = 9% ± 0.2%, and / or the carbon particles have a volume fraction Vc of 1.5% < Vc < 7.5%, in particular

[0029] The solid lubricant particles should have a concentration of 2.0% < Vc < 5.0% and preferably Vc = 2.5% ± 0.1%. With such a proportion of solid lubricant particles, a sufficient self-lubricating effect can be achieved, while with such a proportion of carbon particles, especially graphite particles, consumption of the solid lubricant particles during sintering can be avoided and a high strength of the metal matrix, especially the Fe matrix, can be achieved.

[0030] Preferably, the carbon particles, particularly graphite particles, in a powder mixture for producing a green body for the sintering material have a mean particle size x of 4.5 pm < x < 40 pm and particularly 5.5 pm < x < 35 pm. With such a particle size, a sufficiently large contact area with the metal matrix can be achieved to prevent the consumption of the solid lubricant particles during sintering through a chemical reaction with the metal matrix, while simultaneously avoiding excessive carburizing and embrittlement of the metal matrix.

[0031] The sintering material is particularly preferred at a sintering temperature T of

[0032] 775°C < T < 1000°C, in particular 800°C < T < 900°C and preferably

[0033] 825°C < T < 850°C. The sintering temperature can be adjusted, particularly depending on the volume fraction of carbon and the carbon particle size, to achieve a low coefficient of friction and sufficient strength for the application after sintering. In particular, a comparatively low sintering temperature of less than 1000°C can be used, which is generally higher than the temperature at which the solid lubricant particles would be consumed during sintering without a carbon environment, for example, greater than 775°C for M0S2 as the solid lubricant.

[0034] Specifically, the solid lubricant particles are intended to contain or consist exclusively of M0S2. Alternatively, MoO2 or MoOs can also be used. The suitability of M0S2 as a solid lubricant particle in the sintered material has already been demonstrated.

[0035] Preferably, the metal matrix comprises iron and / or iron compounds and / or iron alloys, or consists exclusively of iron and / or iron compounds and / or iron alloys. The suitability of iron as a metal matrix in the sintered material has already been demonstrated. The metal particles for the metal matrix can, in particular, comprise Fe, C45, C60, 16MnCr5, 42CrMo5, and / or 34CrNiMo6. Particularly preferably, the dispersed carbon particles are in the form of graphite. Carbon not tightly bound in the metal matrix can thus also act as a solid lubricant in the form of graphite, providing a friction-reducing effect, at least in addition to the solid lubricant particles.

[0036] Another aspect of the invention relates to the use of a gear arrangement, which can be designed and further developed as described above, at a maximum surface pressure p max in the support area of ​​400 N / mm 2 < p ma x < 900 N / mm 2 , in particular 500 N / mm 2 < p max < 700 N / mm 2 It is expected that such maximum surface pressures will not be exceeded in a gear arrangement, and that the rather brittle sintered material can withstand such loads for short periods without failing. The solid lubricant particles, which remain unused during sintering thanks to the carbon, in the hard sintered metal matrix of the sintered material enable a high-load-resistant, oil-free, and self-lubricating solid lubrication, thus allowing for a low-wear lubricated gear arrangement.

[0037] A surface pressure p of 150 N / mm² is particularly preferred in regular normal operation on the support surface. 2 < p < 400 N / mm 2 , in particular

[0038] p = 300 N / mm 2 ± 50 N / mm 2It is expected that the rather brittle sintered material will be able to withstand such stresses over a longer period of time without failing.

[0039] In particular, during normal operation, the temperature T in the area of ​​the support surface is 20°C < T < 80°C, preferably 23°C < T < 50°C, and most preferably 25°C < T < 30°C. It is expected that such an operating temperature will not cause thermal damage to the sintered material and / or significantly promote thermally driven creep effects.

[0040] A further aspect of the invention relates to a method for producing a gear arrangement, which can be designed and further developed as described above, in which a powder mixture is provided for producing a green body, wherein the powder mixture comprises metal particles, solid lubricant particles and carbon particles, the green body is formed to form a gear partner having the first tooth or the second tooth, and the green body is sintered at a sintering temperature T of 775°C < T < 1000°C, in particular 800°C < T < 900°C and preferably 825°C < T < 850°C, in order to form the sintered material with the open-pore metal matrix in which the solid lubricant particles and the carbon particles are dispersed, wherein in particular the gear partner is subsequently brought into gear engagement with another gear partner in an oil-free manner.The other gear component is preferably made of a material different from the sintered material, in particular steel, which is more ductile than the sintered material. The method can be further developed and refined, in particular as described above, with reference to the gear arrangement and its use. The unused solid lubricant particles in the hard-sintered metal matrix of the sintered material, produced by the carbon during sintering, provide a high-load-resistant, oil-free, and self-lubricating solid lubrication, thus enabling a low-wear lubricated gear arrangement.

[0041] The sintering process is applied to only one of the gear teeth in the gear assembly. The gear teeth are sintered directly in their final shape. Additional hardening rolling can then increase the load-bearing capacity, whereby the pores of the metal matrix containing the solid lubricant particles should not be sealed or kept open. Furthermore, the gear teeth can also be manufactured as round sintered steel and machined.

[0042] Another aspect concerns a transmission, particularly for a rail vehicle, with a gear arrangement that can be designed and further developed as described above for transmitting transmission power. Preferably, the gear arrangement is part of a spur gear. Particularly preferably, the gear arrangement is part of a planetary gear, wherein the planetary gear is a planet gear of a planetary transmission and a ring gear meshed with the planet gear. The unused solid lubricant particles in the hard-sintered metal matrix of the sintered material, produced by the carbon during sintering, enable a high-load-resistant, oil-free, and self-lubricating solid lubrication, thus allowing for a low-wear lubricated gear arrangement of the transmission.Another aspect concerns a gear coupling for connecting an input shaft to an output shaft, comprising an internal gear and an external gear supported on the internal gear, wherein a gear arrangement, which can be designed and further developed as described above, is formed between the internal and external gears. The gear coupling can be provided in an industrial wind turbine. The associated wind turbine can be designed for industrial power generation and is generally dimensioned for a rated output of at least 2 MW, preferably at least 5 MW, and particularly preferably at least 15 MW, and is specifically designed for offshore operation, which implies a corresponding power density in the gearbox and corresponding dimensions for the components of the wind turbine, in particular the gear arrangement as part of the gearbox.Preferably, the gear coupling is provided in the drive train of a rail vehicle, for example in the direction of power flow between a drive motor and / or gearbox on the one hand and a drive wheel on the other, in particular to provide a rotatable and preferably also tiltable torque-transmitting connection of the drive wheel resting on a rail to a height-adjustable wagon. Compared to a relatively movable gear in a gearbox, the gear coupling exhibits particularly low relative movements in the area of...

[0043] Starting from the support surfaces. The unused solid lubricant particles in the hard-sintered metal matrix of the sintered material, achieved with the help of carbon during sintering, allow for a high-load-resistant, oil-free, and self-lubricating solid lubrication, thus enabling a low-wear lubricated gear arrangement of the gear coupling.

[0044] One further aspect concerns a data agglomerate with data packages summarized in a common file or distributed across different files for representing the three-dimensional shape design and / or the interactions of all components provided in the gear arrangement, which can be designed and further developed as described above, wherein the data packages are prepared, when processed by a data processing device for operating a machine tool for the additive manufacturing of devices, to carry out the additive manufacturing of the components of the gear arrangement, in particular by 3D printing, and / or, when processed by a data processing device for carrying out a technical simulation, to carry out a simulation of the functioning of the gear arrangement and to output the simulation results generated in this way for further use.In particular, for the purpose of providing proof of fatigue strength as a function of variable loads and / or variable temperature stresses and, if necessary, comparing it with measurement data obtained on an actual manufactured device according to the invention and / or on a prototype of the device according to the invention. The data packets of the data agglomerate are specifically adapted to the inventive design of the respective device described above in order to adequately represent the interaction of the components of the device according to the invention during processing in the data processing unit. The data packets can, in particular, be stored in a spatially distributed manner, but adapted to each other in such a way that, in the event that all data packets are combined in a common data processing unit,The data agglomerate thus assembled provides all the necessary data for additive manufacturing and / or technical simulation with the aid of the data processing device for the device according to the invention.

[0045] For example, the data packages are each separate parts of a data library ("Library"), which are combined to form the data agglomerate and are adapted to each other with respect to their relative dimensions and / or absolute dimensions and / or material properties corresponding to the respective device according to the invention. The data agglomerate can represent a virtual embodiment of the respective device according to the invention in the form of a so-called "digital twin," enabling a virtual investigation in the form of a simulation or a physical realization using an additive manufacturing process. Such a digital twin is, for example, presented in US 2017 / 286572 A1, the disclosure of which is hereby incorporated by reference as part of the invention.

[0046] When the machine tool's data processing unit processes the data agglomerate, the device according to the invention is produced, so that after processing the data agglomerate in the data processing unit, the device according to the invention is obtained, at least in the form of a prototype. In particular, each data package can represent a separately executed component of the respective associated device according to the invention, so that the individual components can be easily assembled in their relative position and / or relative mobility, both physically and / or virtually, in order to realize the interactions essential to the invention. In particular, it is possible to use the respective data packages to produce the various components of the respective device separately and, if necessary, from different materials by additive manufacturing and subsequently assemble them into a prototype of the respective device.The division of the data of the data agglomerate into different data packages thus enables in a simple way a sequential additive manufacturing of components of the respective device that can be moved relative to each other in the form of a kit of parts, which is prepared for the interaction of the components of the prototype according to the invention to solve the problem underlying the invention and can then only be meaningfully assembled.

[0047] Additionally or alternatively, it is possible to use the data packages of the data agglomerate in a virtual environment during a technical simulation to calculate and / or predict the individual components of the respective device, their interactions, the physical state, and / or the changes in physical parameters depending on various boundary conditions and / or over time of the associated device according to the invention. This also allows for further use in verifying whether the device according to the invention, based on the assumed configuration and taking into account the assumed simulated influences, is sufficiently suitable for its intended purpose. If the data agglomerate is processed by a data processing device that models the simulation environment, it is possible to investigate the behavior of the device according to the invention, taking into account boundary conditions, particularly changing ones.This makes it possible, for example, to investigate centrifugal force effects on individual components of the device according to the invention as a function of various static and / or dynamic loads and / or different operating temperatures, whereby such simulation results can be incorporated into the creation of a fatigue strength analysis. Preferably, the simulation results obtained after processing the data agglomerate in the data processing unit for the simulation environment are stored in order to compare them with measurement data obtained from a real, manufactured device according to the invention and / or from a prototype of the device according to the invention. This makes it possible to assess the quality of the simulation results obtained using the data agglomerate and / or, particularly in the case of large deviations, to identify measurement errors and / or faulty measurements.This simplifies and improves non-destructive quality control of the device according to the invention.

[0048] The data agglomerate enables the cost-effective production of prototypes and / or computer-based simulations to study the functionality of the device under consideration, identify problems in the specific application, and find improvements. The solution to the problem underlying the invention can be easily and cost-effectively verified using the data agglomerate.

[0049] The invention is explained below by way of example with reference to the accompanying drawings and preferred embodiments, wherein the features shown below can represent an aspect of the invention, either individually or in combination, the scope of protection being defined by the claims. If a feature is shown in combination with another feature in the exemplary drawings and the accompanying description, this serves only to simplify the presentation of the invention and is not intended to imply that this feature cannot also be a further development of the invention without the other feature. The drawings show:

[0050] Fig. 1: a schematic sectional view of a double-jointed coupling for a rail vehicle, Fig. 2: a schematic perspective view of a tooth of a toothed coupling of the double-jointed coupling from Fig. 1 and

[0051] Fig. 3: a diagram showing test results for differently designed sintered materials.

[0052] The double-jointed coupling 10 for a rail vehicle shown in Fig. 1 can couple a wheel hub 12 rolling on a rail to a height-adjustable wagon. A gearbox and / or a drive motor can be provided in the height-adjustable wagon, with drive power being introduced via a spur gear into an external gear 14 of a housing 16 of the double-jointed coupling 10. The drive power can be transmitted via a first gear coupling 18, designed as a curved gear, to a tiltable shaft 19, in particular designed as a continuous hollow shaft, which transmits the drive power to the wheel hub 12 via a second gear coupling 20, in particular also designed as a curved gear and / or splined coupling. The spur gear with the external gear 14, the first gear coupling 18, and / or the second gear coupling 20 can be designed with a solid lubricant.

[0053] A first tooth 22, shown by way of example in Fig. 2, can be part of a first gearing partner of the solid-lubricated timbrel gearing with the external gear 14, the first gear coupling 18, and / or the second gear coupling 20, and interact with a second tooth (not shown) of a second gearing partner. The second tooth 22 has a sintered material 26 at least in a support surface 24 where the teeth are pressed together. Preferably, the entire first tooth 22 and / or the entire first gearing partner is made of the sintered material 26, while the second tooth and the second gearing partner are made of a more ductile material, in particular steel, or vice versa. Preferably, at least the entire cylindrical surface 28 enclosing the corresponding tooth, and in particular additionally the axial sides of the corresponding gearing partner, are formed by the sintered material 26.

[0054] In Fig. 3, a wear rate 30 in 10 is shown in a diagram for various sintered materials 26. 6 mm 3 N 1 m 1 The coefficient of friction 32 was entered. In the test examples, a powder mixture for the production of a green body, from which the sintered material 26 is produced by sintering, was used consisting of 9 volume% M0S2, 2.5 volume% graphite, and the remainder Fe. For the respective test examples, only the particle size of the graphite (between 32 pm, 5.9 pm, and 0.8 pm) and the sintering temperature (between 825°C and 850°C) were varied. The test examples with a sintering temperature of 850°C show comparatively equally good results with a coefficient of friction 32 of approximately 0.10 and a wear rate 30 of approximately 4 x IO. 6 mm 3 N 1 m 1 up to 9 x 10 6 mm 3 N 1m '. A similarly good result is achieved with the test sample using a sintering temperature of 825°C and a particle size of 5.9 pm, whereas the test samples using a sintering temperature of 825°C and a particle size of 0.8 pm and 32 pm show poorer values ​​and greater scatter with respect to the coefficient of friction 32 and the wear rate 30. An optimal sintering temperature for the investigated powder mixture is therefore likely to be closer to 850°C than to 825°C.

Claims

Patent claims 1. Gear arrangement for load transmission, with a first tooth (22) to introduce a load and a second tooth which can be supported on the first tooth (22) on a support surface (24) for transferring the load, wherein the first tooth (22) and / or the second tooth is made of an oil-free, copper-free and self-lubricating sintered material (26), wherein the sintered material (26) has less than 9 volume % M0S2 and wherein the sintered material (26) has an open-pore metal matrix and solid lubricant particles and carbon particles are dispersed in the metal matrix.

2. Gear arrangement according to claim 1, wherein the first tooth (22) is made of the sintered material (26) and the second tooth is made of steel or the second tooth is made of the sintered material (26) and the first tooth (22) is made of steel.

3. Gear arrangement according to claim 1 or 2, wherein in a powder mixture for producing a green body for the sintered material (26) the solid lubricant particles have a volume fraction VF of the total volume. 7.5% < VF < 10.5%, in particular VF = 9% ± 0.2% and / or the carbon particles have a volume fraction Vc of 1.5% < Vc < 7.5%, in particular 2.0% < Vc < 5.0% and preferably Vc = 2.5% ± 0.1%.

4. Gear arrangement according to one of claims 1 to 3, wherein in a powder mixture for producing a green body for the sintered material (26) the carbon particles have a mean particle size x of 4.5 pm < x < 40 pm and in particular 5.5 pm < x < 35 pm.

5. Gear arrangement according to one of claims 1 to 4, wherein the sintered material (26) is sintered at a sintering temperature T of 775°C < T < 1000°C, in particular 800°C < T < 900°C and preferably 825°C < T < 850°C.

6. Gear arrangement according to any one of claims 1 to 5, wherein the solid lubricant particles comprise M0S2 or consist exclusively of M0S2.

7. Gear arrangement according to any one of claims 1 to 6, wherein the metal matrix comprises iron and / or iron compounds and / or iron alloys or consists exclusively of iron and / or iron compounds and / or iron alloys.

8. Gear arrangement according to one of claims 1 to 7, wherein the sintered material (26) has more than 7 volume-% M0S2, in particular more than 7.5 volume-% M0S2.

9. Use of a gear arrangement according to one of claims 1 to 8 at a maximum surface pressure p ma x in the support surface (24) of 400 N / mm 2 < pmax < 900 N / mm 2 , in particular 500 N / mm 2 pmax < 700 N / mm 2 .

10. Use according to claim 9, wherein in regular normal operation a surface pressure p of 150 N / mm² is exerted in the support surface (24).2 < p < 400 N / mm 2 , in particular p = 300 N / mm 2 ± 50 N / mm 2 prevails.

11. Use according to claim 9 or 10, wherein in regular normal operation a temperature T in the area of ​​the support surface (24) of 20°C < T < 80°C is present.

12. Use according to one of claims 9 to 11, wherein in regular normal operation a temperature T in the area of ​​the support surface (24) of 23°C < T < 50°C, preferably of 25°C < T < 30°C, is present.

13. Method for manufacturing a gear arrangement according to any one of claims 1 to 8, wherein a powder mixture is provided for the production of a green body, wherein the powder mixture comprises metal particles, solid lubricant particles and carbon particles, the green body is shaped to form an interlocking partner having the first tooth (22) or the second tooth, and The green body is sintered at a sintering temperature T of 775°C < T < 1000°C, in particular 800°C < T < 900°C and preferably 825°C < T < 850°C, in order to form the sintered material (26) with the open-pore metal matrix in which the solid lubricant particles and the carbon particles are dispersed.

14. Gearbox, in particular for a rail vehicle, with a gear arrangement according to one of claims 1 to 8 for transmitting a gearbox power.

15. Gearbox according to claim 14, wherein the gear arrangement is part of a spur gear and / or the gear arrangement is part of a planetary gear, wherein the planetary gear is a planet gear of a planetary gearbox and a ring gear meshed with the planet gear.

16. Tooth coupling (18, 20) for coupling an input shaft with an output shaft, comprising an internal toothing and an external toothing supported on the internal toothing, wherein a toothing arrangement according to one of claims 1 to 8 is formed between the internal toothing and the external toothing.

17. Data agglomerate comprising data packages combined in a common file or distributed across different files for representing the three-dimensional shape design and / or the interactions of all components provided in the gear arrangement according to any one of claims 1 to 8, wherein the data packages are prepared for this purpose. to carry out additive manufacturing of the components of the gear arrangement, in particular by 3D printing, during processing by a data processing device for the operation of a machine tool for the additive manufacturing of devices. and / or During processing by a data processing device to carry out a technical simulation, a simulation of the functioning of the gear arrangement is to be performed and the simulation results generated are to be output for further use, in particular for the purpose of providing proof of fatigue strength depending on variable loads and / or variable temperature loads.

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