Bearing component for a bearing and method for manufacturing a bearing component

Abstract

A bearing component (1) for a bearing (10) is disclosed, comprising a base element (1') made of a metallic material and at least one load carrying layer (11), wherein the at least one load carrying layer (11) has a hardness of 55 HRC or more, characterized in that the metallic material of the base element (1') has a hardness of 50 HRC or less.

Description

Technical Field

[0001] This invention relates to a bearing component for a bearing and a method for manufacturing the bearing component. Background Technology

[0002] Rolling bearings and plain bearings (or bushing bearings) are well-known mechanical components used to carry loads while allowing relative rotation between their bearing rings. Rolling bearings carry loads via rolling elements (such as balls and rollers), while bushing bearings (also known as plain bearings) carry loads via sliding surfaces.

[0003] Bearing rings are typically manufactured from a single rolled / forged steel substrate through processes such as surface cutting, grinding, and honing until the final bearing ring assembly is provided. Bearing rings often also undergo heat treatment to increase their surface hardness, thereby achieving high fatigue resistance, especially on the load-bearing surfaces of the ring. This results in a long service life.

[0004] It is also known, for example, to provide bearing rings made of more expensive materials to offer improved performance. For example, bearing rings can be made of stainless steel, thus providing corrosion-resistant rings. Because stainless steel is relatively expensive, larger bearings (such as bearings with an outer diameter greater than 500 mm) may be very expensive to produce due to the high material cost, or even impossible to produce due to limitations in the reduction ratio.

[0005] Furthermore, it is known to remanufacture used bearing rings. This is typically done by removing the damaged raceway surface from the bearing ring through machining operations (e.g., grinding). Therefore, in order not to significantly alter the dimensions of the raceway surface, it is possible to remove only a small fraction of the radius. For example, it is known to remove no more than 0.025 mm of material, as seen in the radial direction of the bearing ring. Consequently, this limitation renders many bearing rings unsuitable for remanufacturing. Summary of the Invention

[0006] In view of the above, an object of the present invention is to provide an improved bearing component for a bearing, which can be manufactured cost-effectively and is suitable for remanufacturing. Another object of the present invention is to provide a method for manufacturing a bearing component. Yet another object is to provide an improved rolling bearing or sliding bearing. At least one of these objects is achieved by a bearing component including the features of technical solution 1.

[0007] Therefore, a bearing assembly for a bearing is provided. The bearing assembly includes a base element made of a metallic material and at least one load-carrying layer, wherein the at least one load-carrying layer has a hardness of 55 HRC or greater. The bearing assembly can be a bearing ring, such as the ring of any type of rolling bearing. For example, it can be a ball bearing or a roller bearing, including but not limited to spherical roller bearings, tapered roller bearings, toroidal roller bearings, cylindrical roller bearings, spherical ball bearings, deep groove ball bearings, and angular contact ball bearings. Furthermore, the bearing assembly can be a sliding bearing ring, such as the ring of any type of sliding bearing (e.g., a spherical sliding bearing). Additionally, the bearing assembly can be a rolling element, such as tapered rollers, cylindrical rollers, spherical rollers, needle rollers, etc.

[0008] To provide a bearing component that can be manufactured cost-effectively and is suitable for remanufacturing, the base element's metallic material has a hardness of 50 HRC or less, preferably 45 HRC or less. The advantage of having a base element made of a material with a hardness of 50 HRC or less is that the base element can be more ductile compared to materials typically used in bearing components. This has the additional advantage of making the base element less prone to cracking. Furthermore, even if cracking occurs, crack propagation is less. Moreover, a more ductile base element can have increased resistance to temperature differences. Due to these characteristics, the bearing component can also be remanufactured after reaching the end of its technical life.

[0009] By applying a load-bearing layer with a hardness of 55 HRC or greater to a base element with a hardness of 50 HRC or less, a low-cost substrate (such as low-carbon steel, surface-hardened steel, or cast iron) can be used as the base element, and a layer of harder material (such as martensitic stainless steel or other high-hardness steel) of desired thickness can be added to the outer surfaces of bearing components (such as raceways, rolling surfaces, mounting surfaces, etc.). Furthermore, because the added layer has a hardness of 55 or greater, heat treatment is not required after adding the load-bearing layer.

[0010] Preferably, at least one load-bearing layer is provided to the surface of the base element using a wire-based Directed Energy Deposition (DED) operation and / or a steel powder DED operation. Specifically, by providing the base element with at least one load-bearing layer or load-bearing surface applied by a wire-based and / or powder-based DED operation (such as laser cladding), an improved steel surface can be applied to the surface of the metallic base element, wherein the steel surface is preferably a high-performance steel surface. This allows for the cost-effective production of bearing components, such as rolling or sliding bearing rings and / or rolling elements, with increased service life. More particularly, compared to integral stainless steel products, the DED operation enables the manufacture of corrosion-resistant bearing components in a more cost-effective manner.

[0011] Furthermore, by using DED (Damaged Fiber Enamel), a thicker layer of steel can be applied to the base element, which means further improved performance and also increases the possibility of remanufacturing more types of bearing components. Because the material of the load-bearing surfaces is added to the base element, these surfaces can be machined and reclad repeatedly, bringing the bearing closer to new each time.

[0012] This invention also provides increased flexibility because it enables the customization of load-bearing surface materials for applications with specific requirements, such as those for pulp and paper, wind turbines, metal and mining industries, etc. Load-bearing surface, as defined herein, means a surface designed to withstand loads (typically alternating loads) during use.

[0013] Preferably, at least one load-bearing layer or load-bearing layer can be a raceway surface of a rolling bearing element or a sliding bearing element (such as a bearing ring, bushing, housing, shaft, etc.), and / or a rolling surface of a rolling element. However, the load-bearing surface can also be, for example, the inner circumferential surface of an inner bearing ring and / or the outer circumferential surface of an outer bearing ring. Furthermore, the load-bearing surface can be any surface of a bearing component designed to bear a load, wherein the main force component points substantially straight toward that surface.

[0014] As used herein, DED (such as laser cladding) refers to a surface welding operation that enables the bonding of wire material and / or steel powder metallurgy to a base element of metal, thereby providing a DED-bonded surface on the base element. Other examples of DED besides laser cladding are plasma transferred arc (PTA), electron beam melting (EBM), and wire arc additive manufacturing (WAAM).

[0015] Optionally, the steel wire and / or steel metal powder preferably contain carbon (C) and / or boron (B) as a hardening mechanism. That is, it has been recognized that DEDs (e.g., laser cladding) containing only C as a hardening mechanism may not provide a surface with sufficient surface hardness and no high risk of cracking. In particular, it has been found that raceway surfaces coated with steel wire and / or steel metal powder containing only C as a hardening mechanism may not provide sufficient surface hardness (especially for more demanding applications) and no high risk of cracking in the raceway surface. Therefore, by also providing B as a hardening mechanism, it has been recognized that high surface hardness of the load-bearing surface can be achieved, which is suitable for more demanding applications, while also reducing the risk of cracking.

[0016] This is accomplished by using a low-cost metal substrate (ring core) and adding layers of martensitic stainless steel or other high-hardness steel of the desired thickness to the raceways and mounting surfaces of the outer and inner rings in the rolling bearing. Since the added layers have a hardness of approximately 55 HRC to 58 HRC during cladding, no heat treatment is required after LMD (Low-Density Molding).

[0017] For example, it has been found that when steel metal powder and / or steel wire contain C and B as a hardening mechanism, a load-bearing surface with a surface hardness of at least 55 HRC (such as 55 HRC to 58 HRC) can be achieved. Alternatively, the steel wire and / or steel metal powder may contain 0.10 wt% (i.e., weight %) to 0.50 wt% of C and / or 0.50 wt% to 1.20 wt% of B. For example, it has been found that by using the aforementioned amounts of C and B, typically by using a higher amount of B compared to, for example, the amount of C in steel metal powder, a higher surface hardness can be achieved. According to one example embodiment, the total wt% of C and B is in the range of 0.6 wt% to 1.7 wt%, such as substantially 0.2 wt% of C and 0.9 wt% of B.

[0018] Optionally, the steel wire and / or steel metal powder can be stainless steel wire and / or stainless steel metal powder, respectively. This allows for the provision of corrosion-resistant surfaces through a DED operation, meaning a high-performance surface compared to, for example, the base material of the base element. For instance, inexpensive materials can be used for the base element, such as standard steels that are not stainless steel, for example, steels with a chromium (Cr) content of less than 12 wt%. More specifically, the use of a DED operation also allows for the provision of stainless steel bearing components not only for small and medium-sized bearings but also for large-sized bearings.

[0019] Preferably, the base element can be made of low-carbon steel. For example, 16MnCr5, 20MnCr5, 42CrMo4, 100Cr6, etc., can be used as the material for the base element. Alternatively, the base element can be made of casehardening steel or cast iron.

[0020] Optionally, the load-bearing surface may include more than one layer, such as 2 to 20 layers, applied using a DED. Providing more than one layer (such as 2 to 20 layers) has been shown to produce high-performance surfaces with satisfactory thicknesses for more demanding applications. This also reduces heat transfer to the metal base element, meaning a lower risk of cracking in the metal base element.

[0021] Optionally, the application speed can be varied during the application of the wire material and / or steel metal powder to the metal base element. This allows one or more layers with different radial thicknesses to be applied to the metal base element. For example, the metal base element can be rotated relative to its axis of rotation while the load-bearing layer is applied, wherein the rotation speed is varied during the application of the wire and / or steel metal powder to the metal base element. By varying the speed, less heat can be transferred to the metal base element during DED operation.

[0022] According to one example implementation, the speed is varied by reducing the speed at least once during the application of the load-bearing surface. Thus, a relatively high speed can be used when, for example, the first layer is applied directly to the base element of the metal, and a relatively low speed can be used when one or more additional layers are applied on top of the first layer. Consequently, the first layer will be thinner than the one or more additional layers. This results in less heat being transferred to the base element of the metal, thereby reducing the risk of cracking therein during DED (e.g., laser cladding) operations.

[0023] Furthermore, by varying the application speed, a load-bearing surface with a substantially uniform thickness can be provided for a surface with a varying radius. For example, a bearing component may have a spherical surface with a varying radius, thereby allowing the application speed to be varied to provide a load-bearing surface with a substantially uniform thickness thereon. Therefore, the application speed can be varied to achieve a constant surface velocity during DED operation. Optionally, the final thickness of the applied load-bearing surface can be from 0.25 mm to 10 mm, as seen in the radial direction of the bearing component.

[0024] According to another embodiment, at least one side of the base element is provided with at least one fixing opening for securing the bearing assembly during at least the application of the load-bearing layer. For example, the fixing opening can be used to secure the bearing assembly during wire-directed energy deposition (DED) operations and / or steel powder DED operations and / or machining operations of the bearing assembly. The fixing opening can be a hole, preferably a threaded hole. Providing at least one fixing opening on the side of the bearing assembly allows almost all manufacturing to be completed using a single setup. More specifically, at least one fixing opening on the side of the base element allows all pre-machining, surface treatment, and post-machining to be performed in the same setup or machine when manufacturing the product or bearing assembly. This allows for product recycling. More specifically, when a normal bearing reaches the end of its life, it is typically scrapped. When worn, the aforementioned bearing assembly can be disassembled at the customer's site and sent back to its manufacturer for recycling. It can then be pre-machined, surface-treated, and post-machined. This can be done in the same setup, and the bearing components can be sent back to the customer with new reinforced raceways ready for a second life. This process can be repeated several times, so the product will be truly cyclical.

[0025] According to another aspect, a method for manufacturing bearing components for bearings is provided. The method includes at least the following steps:

[0026] - Provide base elements made of a metallic material with a hardness of 50 HRC or less; and

[0027] - Apply a load-bearing layer to at least one surface of the base element, wherein at least one load-bearing layer has a hardness of 55 HRC or greater.

[0028] Optionally, the method may further include: - removing the old load-bearing surface of the bearing assembly before applying the load-bearing surface, such as removing 0.25 mm to 10 mm of material from the bearing assembly, as seen in the radial direction of the base element.

[0029] Preferably, the method further includes the step of providing at least one fixing opening at the side of the base element, the fixing opening being used to fix the bearing assembly during at least the application of the load-bearing layer. For example, the fixing opening may be used to fix the bearing assembly during wire-directed energy deposition (DED) operations and / or steel metal powder DED operations and / or machining operations of the bearing assembly.

[0030] Therefore, this method can be used for remanufacturing components of rolling or sliding bearings that are already in use. Thus, by first removing the old load-bearing surfaces, preferably the old raceway or rolling surfaces, a new high-performance layer can be applied to the metal base element by applying a new load-bearing surface (e.g., using a DED operation). Preferably, the thickness of the newly applied load-bearing surface is equal to or at least substantially equal to the thickness of the material removed from the metal base element. Here, substantially equal to means within the range of 100% to 150% of the original thickness, such as 100% to 130% or 100% to 110% of the original thickness, depending on the surface roughness after deposition. This allows the original dimensions of the bearing component to be maintained.

[0031] Optionally, the speed at which the load is applied to the bearing surface via DED (i.e., the DED speed, such as the laser cladding speed) can range from 0.5 m / min to 1000 m / min. According to one example embodiment, the DED speed is higher than 1 m / min, such as higher than 20 m / min, for example, 80 m / min to 120 m / min, which means a reduced risk of cracking in the base element. That is, it has been found that higher DED speeds (such as laser cladding speeds) can reduce the risk of cracking. Thus, by using, for example, higher laser cladding speeds, improved bearing components can be provided.

[0032] Optionally, when the DED operation is laser cladding, the laser power used when applying the load to the bearing surface can be from 1 kW to 15 kW, such as from 2 kW to 6 kW.

[0033] Therefore, the present invention also relates to a bearing comprising at least one bearing component according to the present invention.

[0034] Further preferred embodiments are defined in the dependent claims, as well as in the specification and drawings. Thus, elements described or shown in combination with other elements may exist alone or in combination with other elements without departing from the scope of protection. Attached Figure Description

[0035] Preferred embodiments of the invention are described below with reference to the accompanying drawings, which are merely illustrative and not intended to limit the scope of protection. The scope of protection is defined only by the appended claims.

[0036] The attached diagram shows:

[0037] Figure 1 Cross-sectional view of the bearing components according to the first embodiment.

[0038] Figure 2 : A schematic side view of a rolling bearing according to the second embodiment.

[0039] Figure 3 Cross-sectional view of the bearing components according to the third embodiment.

[0040] Figure 4 According to the cross-sectional view of the bearing components in the fourth embodiment, and

[0041] Figure 5 : A flowchart of the method according to the fifth embodiment. Detailed Implementation

[0042] In the following text, elements that are the same or have similar functions are indicated by the same reference numerals.

[0043] It should be noted that the accompanying drawings are not necessarily drawn to scale, and for clarity, the dimensions of some features may have been exaggerated.

[0044] Figure 1 A cross-sectional view of a bearing component 1 according to a first embodiment is depicted, wherein the bearing component 1 is a rolling bearing ring or a sliding bearing ring. The cross-sectional view is defined by a plane extending along the axis of rotation A of the bearing ring 1. The bearing component 1 includes a metallic base element 1', which, in the illustrated embodiment, is a steel ring. The metallic material of the base element 1' has a hardness of 50 HRC or less, preferably 45 HRC or less. This has the advantage that the base element 1' can be more ductile compared to other materials typically used for bearing components.

[0045] The bearing component 1 also includes a load-bearing surface 11 disposed on the base element 1'. The load-bearing layer or load-bearing surface 11 has a hardness of 55 HRC or greater. The load-bearing surface 11 can be applied to the metal base element 1' by DED operation.

[0046] The load-bearing surface 11 here is a raceway surface, such as the raceway surface used for rolling elements (i.e., balls and / or rollers). As shown, the raceway surface 11 can have a spherical shape. Thus, bearing component 1 can be misaligned relative to the outer ring 2 (see Figure 1). Figure 2 Thus, the rolling bearing or sliding bearing 10 (such as bearing component 1) includes the bearing assembly 1. Figure 2 The rolling bearing shown is able to adapt to shaft deflection during use.

[0047] Accordingly, Figure 2 The description includes a rolling bearing component 1 (e.g., such as...) Figure 1The image shows a side view of the rolling bearing 10. The bearing component 1 here is the inner ring of the rolling bearing 10. The rolling bearing 10 also includes the outer ring 2 mentioned above and a plurality of rolling elements 3 disposed between the outer ring 2 and the bearing ring 1. It should be understood that, alternatively or additionally, the outer ring 2 and / or the rolling elements 3 may also be provided with load-bearing surfaces 11.

[0048] Figure 3 A cross-sectional view of a portion of a bearing component 1 according to a third embodiment is depicted. It includes a load-bearing surface 11 and a metal base element 1', wherein the load-bearing surface 11 has been applied accordingly via a DED. The load-bearing surface 11 has a radial thickness h1, which can be from 0.25 mm to 10 mm. The radial direction of the bearing component 1 is perpendicular to and intersects the axis of rotation A of the bearing component 1. The metal base element 1' has a radial thickness h2 significantly greater than the radial thickness h1, such as from 10 mm to 500 mm.

[0049] Figure 4 A cross-sectional view of the bearing component 1 according to the fourth embodiment is shown after the load-bearing surface 11 has been applied and before the post-machining steps are performed to obtain the final bearing component 1. (See from...) Figure 4 As can be seen, the base element 1' of the bearing component 1 is provided with at least one fixing opening 5, and the at least one fixing opening 5 is provided on the side 6 of the bearing component 1. Figure 4 In the middle, the fixed opening 5 is a threaded hole.

[0050] The fixing opening 5 can be used to fix the bearing assembly 1 during wire-directed energy deposition (DED) operations and / or steel powder DED operations and / or machining operations of the bearing assembly 1. After the load-bearing surface 11 has been applied, the final contour of the bearing assembly 1 is achieved in a further machining step, which is formed by... Figure 4 The solid line 7 in the figure depicts this. Advantageously, the fixing opening 5 is used not only to fix the bearing assembly 1 during the application of the load-bearing layer 11, but also during the machining process. This allows the bearing assembly 1 to be cyclical.

[0051] exist Figure 5 The diagram shows a flowchart of a method according to an exemplary embodiment of the present invention. This method is for manufacturing bearing component 1. The method includes:

[0052] S1: Provides a base element 1' made of a material with a hardness of 50 HRC or less; and

[0053] S2: Apply at least one load-bearing layer 11 to the base element 1' of the metal, wherein at least one load-bearing layer 11 has a hardness of 55 HRC or greater.

[0054] At least one load-bearing layer 11 can be applied using wire-directed energy deposition (DED) operations and / or steel metal powder DED operations. For example, the DED operation can be a laser cladding operation.

[0055] The steel wire and / or steel metal powder applied to the base element 1' preferably contains C and B as a hardening mechanism, thereby forming carbides and borides in the applied steel material. For example, as mentioned above, the steel wire and / or steel metal powder may contain 0.10 wt% to 0.50 wt% C and 0.50 wt% to 1.20 wt% B, such as 0.15 wt% to 0.30 wt% C and 0.60 wt% to 0.90 wt% B. It has been found that a larger wt% C may increase the risk of cracking in the load-bearing surface 11. Thus, by having a lower amount of C and a higher amount of B, sufficient surface hardness, such as greater than 55 HRC, can be achieved while reducing the risk of initiating cracks in the load-bearing surface 11.

[0056] The steel wire and / or steel metal powder used to form the load-bearing surface 11 can be stainless steel wire and / or stainless steel metal powder, thereby providing a corrosion-resistant surface 11. For example, this allows for the cost-effective provision of a corrosion-resistant load-bearing surface on a large bearing component 1.

[0057] Preferably, applying the load-bearing surface 11 involves applying more than one layer, such as 2 to 20 layers, using a DED. Furthermore, the application speed can be varied during the application of the wire material and / or steel metal powder onto the base element 1'. For example, the speed can be varied by reducing the speed at least once during the application of the load-bearing surface 11. Thus, a thin layer can be initially provided on the base element 1', followed by one or more thicker layers as the application speed is reduced, until a final radial thickness hi of, for example, is achieved, is reached. The method may also include an optional step S12 (indicated by the dashed box). Step S12 includes:

[0058] - Before applying the load-bearing surface 11, the old load-bearing surface of the base element 1' is removed, such as by removing 0.25 mm to 10 mm of material from the base element 1', as seen in the radial direction of the base element 1'. Therefore, the present invention can be a method for remanufacturing a used bearing component 1. The powder fraction of the steel metal powder can be from 30 pm to 200 pm.

[0059] Furthermore, step S2 can be followed by machining steps on the applied load-bearing surface 11, such as grinding and / or honing. As seen in the cross-sectional view, for example in... Figure 1 The load-bearing surface 11 of the bearing component 1 shown has a varying radius. In this embodiment, the radius is varied, forming a spherical outer profile. According to an example embodiment, the rotational speed of the base element 1' is changed during the DED step to achieve a constant surface speed. This allows for the acquisition of a surface layer 11 with a uniform thickness.

[0060] Figure Labels

[0061] 1. Bearing components

[0062] 1' Base element

[0063] 2 Outer ring

[0064] 3 Rolling elements

[0065] 5. Fixed opening

[0066] 6. Side view

[0067] 7 solid lines

[0068] 10 Rolling bearings

[0069] 11 Load-bearing surface

[0070] A. Rotation axis

Claims

1. A bearing component (1) for a bearing (10), comprising a base element (1') made of a metallic material and at least one load-bearing layer (11), wherein, The at least one load-bearing layer (11) has a hardness of 55 HRC or greater, characterized in that the metal material of the base element (1') has a hardness of 50 HRC or less.

2. The bearing component (1) according to claim 1, characterized in that, The at least one load-bearing layer (11) is provided on the surface of the base element by means of wire-directed energy deposition (DED) operation and / or steel metal powder DED operation.

3. The bearing component (1) according to claim 1 or 2, characterized in that, The metal material of the base element (1') is selected from one of the following groups of materials: low carbon steel, surface hardened steel or cast iron.

4. The bearing component (1) according to any one of the preceding claims, characterized in that, The steel wire and / or steel metal powder contains carbon (C) and / or boron (B), wherein, preferably, the steel wire and / or steel metal powder contains 0.10 wt% to 0.50 wt% of C and / or 0.50 wt% to 1.20 wt% of B.

5. The bearing component (1) according to any one of the preceding claims, characterized in that, The steel wire and / or steel metal powder are stainless steel wire and / or stainless steel metal powder, and / or high-hardness steel powder and / or high-hardness steel wire, respectively.

6. The bearing component (1) according to any one of the preceding claims, characterized in that, As seen in the radial direction of the bearing component (1), the final thickness of the load-bearing layer (11) is 0.25 mm to 10 mm.

7. The bearing component (1) according to any one of the preceding claims, characterized in that, At least one side (6) of the base element (1') is provided with at least one fixing opening (5) for fixing the bearing component (1) during at least the application of the load-bearing layer (11).

8. A method for manufacturing a bearing component (1) for a bearing (10), comprising the following steps - Provides a base element (1') made of a metallic material with a hardness of 50 HRC or less; and - At least one load-bearing layer (11) is applied to at least one surface of the base element (1'), wherein, The at least one load-bearing layer (11) has a hardness of 55 HRC or greater.

9. The method according to claim 8, further comprising: - Before applying the at least one load-bearing layer (11), remove the old load-bearing layer (11) of the metal base element (1'), such as removing 0.25 mm to 10 mm of material from the metal base element (1'), as seen in the radial direction of the metal base element (1').

10. The method according to claim 8 or 9, further comprising: The step of providing at least one fixing opening (5) on the side (6) of the base element (1') for fixing the bearing component (1) during at least the application of the load-bearing layer (11).

Images