Rolling bearing component, rolling bearing, and method and use

Abstract

The invention relates to a rolling bearing component (1), in particular in the form of a bearing ring (6, 6a, 6b) or a rolling element (7), comprising a metal substrate (2) and a layer system (3, 3') applied galvanically and / or chemically to the metal substrate (2) at least on a running surface (4) of the rolling bearing component (1), wherein the layer system (3, 3') optionally comprises a first layer (3a) arranged on the metal substrate (2) and at least one second layer (3b) arranged on the metal substrate (2) or, if applicable, on the first layer (3a), wherein the optional first layer (3a) is formed of nickel and the at least one second layer (3b) is formed of a tin-nickel alloy, wherein non-metal particles (5) are integrated in the tin-nickel alloy in the form of graphite and / or molybdenum disulphide and / or titanium carbide and / or tungsten carbide and / or diamond. The invention also relates to a rolling bearing (10) and to a method for producing the rolling bearing component (1), and to a use.

Description

[0001] Rolling bearing component, rolling bearing, as well as methods and uses

[0002] The invention relates to a rolling bearing component comprising a metal substrate and a layer system applied galvanically and / or chemically to the metal substrate at least on a running surface of the rolling bearing component, wherein the layer system optionally comprises a first layer arranged on the metal substrate and at least one second layer arranged on the metal substrate or, if present, on the first layer.

[0003] Such rolling bearing components are already disclosed in DE 10 2010 045 321 A1, where a galvanic coating in the form of a zinc-iron alloy is described.

[0004] DE 195 29 379 A1 also describes a rolling bearing component in the form of a rolling bearing cage made of an iron material, the surface of which is wholly or partially provided with a galvanically produced coating of nickel or a nickel alloy or copper or a copper alloy or silver.

[0005] DE 10 2015 213 335 A1 describes a rolling bearing with an inner ring and an outer ring coated with a zinc-nickel alloy.

[0006] WO 2016 131 916 A1 describes an electroplated tin-nickel layer tempered at at least 200°C with a high Vickers hardness of at least 750 HV.

[0007] DE 102 62 102 B4 describes a method for the cathodic pulsed current electrodeposition of a selected metallic material onto an electrically conductive substrate in nanocrystalline form. The method uses a drum deposition process for the continuous production of nanocrystalline films.

[0008] German patent application GB 2 535 997 A discloses a method for pulse electroplating a tin composite coating containing particles in a tin or tin alloy matrix for a sliding bearing component. Intermediate layers can be arranged between the sliding bearing component and the coating. German patent application DE 10 2007 028 215 A1 describes a method for producing a structured coated sliding element in which metal or a metal alloy is electrolytically deposited onto a sliding element.

[0009] The object of the invention is to provide a particularly wear-resistant coating for rolling bearing components and thus for rolling bearings. Furthermore, a suitable method for manufacturing such a rolling bearing component is to be provided.

[0010] The problem is solved for the rolling bearing component comprising a metal substrate and a layer system applied to the metal substrate galvanically and / or chemically at least on one running surface of the rolling bearing component, in that the layer system optionally comprises a first layer arranged on the metal substrate and at least one second layer arranged on the metal substrate or, if present, on the first layer, wherein the optional first layer is formed of nickel and the at least one second layer is formed of a tin-nickel alloy, wherein non-metallic particles in the form of graphite and / or molybdenum disulfide and / or titanium carbide and / or tungsten carbide and / or diamond are incorporated in the tin-nickel alloy.

[0011] The coating system is tribologically active and exhibits high wear resistance. If it contains particles of graphite and / or molybdenum disulfide, friction and thus adhesive wear are reduced. These particles provide lubrication and therefore delay bearing wear. If it contains particles of titanium carbide and / or tungsten carbide and / or diamond, abrasive wear can be reduced. Depending on the application, particles with lubricating properties (in this case, graphite and / or molybdenum disulfide) or particles against abrasive wear (in this case, titanium carbide and / or tungsten carbide and / or diamond) can be used independently or in combination. The use of graphite particles has proven particularly effective, as they interact optimally with the lubricants used in rolling bearings by promoting complete wetting of the coated running surfaces.In particular, the use of non-metallic particles in the form of graphite, in combination with one or more of the aforementioned non-metallic particles, has proven effective. Preferably, the particle size of the particles used is in the range of 1 nm to 10 pm. Diamond particles, in particular, have a particle size in the range of 1 to 10 nm. Graphite particles, in particular, have a particle size in the range of 1 to 10 pm. Molybdenum disulfide, titanium carbide, or tungsten carbide particles, in particular, have a particle size in the range of 1 to 100 nm.

[0012] In this context, rolling bearing components in the form of bearing rings or rolling elements are particularly preferred; however, cages or other components with a raceway can also constitute the rolling bearing component. Suitable rolling bearings include tapered roller bearings, cylindrical roller bearings, needle roller bearings, ball bearings, spherical roller bearings, and similar designs.

[0013] For the rolling bearing component, it has proven particularly effective if the tin-nickel alloy is formed with a nickel content in the range of 20 to 35 wt.%.

[0014] The metal substrate of the rolling bearing component is preferably made of steel, in particular stainless steel. Bearing steels such as 100Cr6 and the like are especially preferred for forming the metal substrate.

[0015] Furthermore, it has proven advantageous if the first layer has a thickness in the range of 1 to 5 pm, particularly in the range of 1 to 3 pm, and / or the at least one second layer has a thickness in the range of 1 to 12 pm, particularly in the range of 1 to 6 pm. Preferably, the entire layer system has a thickness in the range of 2 to 15 pm, particularly preferably in the range of 2 to 9 pm, particularly in the range of 2 to 3 pm.

[0016] Preferably, the at least one second layer has a micro- or nanocrystalline structure. The second layer is considered microcrystalline, in particular, if its grain sizes are in the range of a few micrometers. The second layer is considered nanocrystalline, in particular, if its grain sizes are in the range of less than 100 nm. In particular, the layer system is tempered such that it has a Vickers hardness of

[0017] > 1000 HV.

[0018] The problem is solved for a rolling bearing which comprises at least one rolling bearing component according to the invention.

[0019] In particular, the rolling bearing component is a bearing ring or a rolling element. Examples of rolling bearings include tapered roller bearings, cylindrical roller bearings, needle roller bearings, ball bearings, spherical roller bearings, and similar designs.

[0020] The problem is solved for the method of manufacturing a rolling bearing component according to the invention by the following steps:

[0021] - Providing the metal substrate,

[0022] - optional application of the first layer to the metal substrate in the area of ​​the running surface of the rolling bearing component, and

[0023] - Applying at least one second layer containing the non-metallic particles to the first layer, if present, or to the metal substrate in the area of ​​the running surface of the rolling bearing component, wherein at least one second layer is formed by means of pulsed electroplating.

[0024] Pulsed deposition of at least one second layer leads to a significant increase in the hardness of at least one second layer.

[0025] To achieve a fine-grained, nanoscale deposition, the surface to be coated must have as many nucleation sites for layer growth as possible. This requires a high rate of crystal nucleation and, conversely, a low rate of crystal growth. The resulting formation of as many crystal nuclei as possible in close proximity to one another, whose crystal growth stops as soon as they reach a neighboring nucleus or crystal, creates a coating with a defined micro- or nanocrystalline structure. In practice, this can be achieved through pulsed deposition of the coating. Either the electric current or the electric voltage is pulsed in the millisecond range. Each current or voltage pulse is always followed by a quiescent phase, also in the millisecond range.This pulse profile allows the deposition of a micro- or nanocrystalline structure as described above, since the current peaks generated by the electrical pulse massively increase the speed of crystal nucleation.

[0026] The following parameters have proven effective for separation:

[0027] The duration of the current pulses is in the range of 1 to 10 ms.

[0028] The duration of the resting phases ranges from 1 to 10 ms.

[0029] The duration of the current pulses and the duration of the rest phases can be selected differently. The chosen temperature, pH value, and current density generally depend on the base electrolyte used for the deposition of at least one second layer.

[0030] This makes the coating process particularly economical and also toxicologically safe.

[0031] The process is preferably carried out by applying the coating system in a drum process or a rack process. This further increases the efficiency of the process.

[0032] Preferably, the coating system is applied only to the running surfaces of the rolling bearing component, for which a rack method is particularly suitable.

[0033] A rack coating process is described, for example, in EP3178970 A1. In the equally suitable drum coating process, several rolling elements are moved and coated simultaneously in a coating bath located in a rotating drum. The drum coating process is particularly suitable for coating the entire surface of the metal substrate, but partial coating can also be achieved by applying covers to the metal substrate.

[0034] Furthermore, it has proven beneficial for the process to subsequently temper the layer system at a temperature in the range of 150 to 750°C, particularly in the range of 180 to 250°C, for a period of 20 to 70 minutes, especially in the range of 30 to 60 minutes. This significantly increases the hardness of at least one second layer.

[0035] The use of a layer system on a running surface of a rolling bearing component, in particular in the form of a bearing ring or a rolling element, wherein the layer system is formed galvanically and / or chemically on a metal substrate of the rolling bearing component, wherein the layer system optionally comprises a first layer arranged on the metal substrate and at least one second layer arranged on the metal substrate or, if present, on the first layer, wherein the optional first layer is formed from nickel and the at least one second layer is formed from a tin-nickel alloy, wherein non-metallic particles in the form of graphite and / or molybdenum disulfide and / or titanium carbide and / or tungsten carbide and / or diamond are incorporated into the tin-nickel alloy, has proven particularly successful.In particular, the use of non-metallic particles in the form of graphite, alone or in combination with one or more of the aforementioned non-metallic particles, has proven effective.

[0036] Figures 1 to 4 are intended to illustrate, by way of example, a rolling bearing component, a rolling bearing, and a method for manufacturing the rolling bearing component. Thus, they show:

[0037] Figure 1 shows a rolling bearing in a three-dimensional view.

[0038] Figure 2 shows the section ll-ll through the rolling bearing according to Figure 1 ,

[0039] Figure 3 shows an enlarged section of a rolling bearing component in cross-section, and

[0040] Figure 4 shows an enlarged section of another rolling bearing component in the

[0041] Cut.

[0042] Figure 1 shows a rolling bearing 10 in the form of a ball bearing (shown here only as an example) in a three-dimensional view. The rolling bearing 10 has several rolling bearing components 1, here the bearing rings 6, such as an inner bearing ring 6a and an outer bearing ring 6b. Rolling elements 7 and a cage 8 are also present.

[0043] Figure 2 shows a section 11-11 through the rolling bearing 10 according to Figure 1. Visible are the coating systems 3 applied to the respective running surfaces 4 of the bearing rings 6, 6a, 6b on the metal substrates 2. The rolling elements 7 and the cage 8 do not have a coating with a coating system 3 here, but could also have one.

[0044] Figure 3 shows an enlarged section of a rolling bearing component 1 in the form of the inner bearing ring 6a in the area of ​​the layer system 3 and the running surface 4 in the cross-sectional view of Figure 2. It can be seen that the layer system 3 here only has a second layer 3b made of the tin-nickel alloy, which contains particles, here of graphite. Several second layers 3b may be present.

[0045] The layer system 3 is formed on the metal substrate 2 by providing the metal substrate 2 and forming the second layer 3b, containing the non-metallic particles 5, here in the form of graphite, on the metal substrate 2 in the area of ​​the running surface 4 of the rolling bearing component 1, here the inner bearing ring 6a. The second layer 3b is formed by pulsed electroplating with a layer thickness in the range of 3 to 6 pm. Subsequently, the layer system 3 is annealed at a temperature of 200°C for a period of 30 min or at a temperature of 250°C for a period of 60 min.

[0046] Figure 4 shows a further enlarged section of a rolling bearing component 1 in the form of the inner bearing ring 6a in the area of ​​a layer system 3' and the running surface 4 according to a cross-sectional view in Figure 2. It can be seen that the layer system 3' here has a first layer 3a made of nickel and a second layer 3b made of the tin-nickel alloy, which contains particles, here of graphite. Several second layers 3b may be present.

[0047] The layer system 3' is formed on the metal substrate 2 by providing the metal substrate 2 and depositing the first layer 3a of nickel with a thickness of 1 pm onto the metal substrate 2 in the area of ​​the running surface 4 of the rolling bearing component 1, here the inner bearing ring 6a. Subsequently, the second layer 3b, containing the non-metallic particles 5, here in the form of graphite, is formed on the first layer 3a in the area of ​​the running surface 4 of the rolling bearing component 1, here the inner bearing ring 6a. The second layer 3b is formed by pulsed electroplating with a thickness in the range of 3 to 6 pm. The layer system 3' is then annealed at a temperature of 200°C for a period of 30 minutes.

[0048] List of reference signs

[0049] Rolling bearing component, metal substrate, 3-layer system: a first layer, b second layer, running surface, particles, bearing ring, a inner bearing ring, b outer bearing ring, rolling elements, cage, 0 rolling bearing

Claims

Patent claims 1. Rolling bearing component (1), in particular in the form of a bearing ring (6, 6a, 6b) or a rolling element (7), comprising a metal substrate (2) and a layer system (3, 3') applied electroplated and / or chemically to at least one running surface (4) of the rolling bearing component (1), wherein the layer system (3, 3') optionally comprises a first layer (3a) arranged on the metal substrate (2) and at least one second layer (3b) arranged on the metal substrate (2) or, if present, on the first layer (3a), wherein the optional first layer (3a) is formed of nickel and the at least one second layer (3b) is formed of a tin-nickel alloy, wherein the tin-nickel alloy contains non-metallic particles (5) in the form of graphite and / or molybdenum disulfide and / or titanium carbide and / or Tungsten carbide and / or diamond are present.

2. Rolling bearing component (1) according to claim 1, wherein the tin-nickel alloy is formed with a nickel content in the range of 20 to 35 wt.%.

3. Rolling bearing component (1 ) according to one of claims 1 or 2, wherein the metal substrate (2) is made of steel, in particular stainless steel.

4. Rolling bearing component (1 ) according to one of claims 1 to 3, wherein the first layer (3a) has a layer thickness in the range of 1 to 5 pm and / or wherein the at least one second layer (3b) has a layer thickness in the range of 1 to 12 pm.

5. Rolling bearing component (1 ) according to one of claims 1 to 4, wherein the second layer (3b) has a microscale or nanoscale structure.

6. Rolling bearing component (1 ) according to one of claims 1 to 5, wherein the layer system (3, 3') is tempered such that the layer system (3, 3') has a Vickers hardness of > 1000 HV.

7. Rolling bearing (10), comprising at least one rolling bearing component (1) according to one of claims 1 to 6, in particular in the form of a bearing ring (6, 6a, 6b) or a rolling element (7).

8. Use of a layer system (3, 3') on a running surface (4) of a rolling bearing component (1), in particular in the form of a bearing ring (6, 6a, 6b) or a rolling element (7), wherein the layer system (3, 3') is formed electroplated and / or chemically on a metal substrate (2) of the rolling bearing component (1), wherein the layer system (3, 3') optionally comprises a first layer (3a) arranged on the metal substrate (2) and at least one second layer (3b) arranged on the metal substrate (2) or, if present, on the first layer (3a), wherein the optional first layer (3a) is formed of nickel and the at least one second layer (3b) is formed of a tin-nickel alloy, wherein the tin-nickel alloy contains non-metallic particles (5) in the form of graphite and / or molybdenum disulfide and / or titanium carbide. and / or tungsten carbide and / or diamond are incorporated.

9. Method for manufacturing a rolling bearing component (1 ) according to any one of claims 1 to 6, comprising the following steps: - Providing the metal substrate (2), - optional application of the first layer (3a) to the metal substrate (2) in the area of ​​the running surface (4) of the rolling bearing component (1), and - Applying at least one second layer (3b) containing the non-metallic particles (5) to the first layer (3a), if present, or to the metal substrate (2) in the area of ​​the running surface (4) of the rolling bearing component (1), wherein at least one second layer (3b) is formed by means of pulsed electroplating.

10. Method according to claim 9, wherein the application of the layer system (3, 3) is carried out in a drum process or a rack process.

11. Method according to claim 9 or 10, wherein the layer system (3, 3') is subsequently tempered at a temperature in the range of 150 to 750°C, in particular in the range of 180 to 250°C, for a period of time in the range of 20 to 70 min, in particular in the range of 30 to 60 min.

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