A METHOD FOR MANUFACTURING A ROLLING OR PLAIN BEARING RING

Abstract

A method for manufacturing a rolling or plain bearing ring includes providing a metallic ring member and applying a load carrying surface onto the metallic ring member by use of a steel wire Directed Energy Deposition (DED) operation and/or a steel metal powder DED operation. Preferably, the steel wire and/or the steel metal powder includes 0.10-0.50 wt % of carbon and 0.50-1.20 wt % of boron.

Claims

1. A method for manufacturing a rolling or plain bearing ring, the method comprising the steps of: providing a metallic ring member; and applying a load carrying surface onto the metallic ring member by use of a steel wire Directed Energy Deposition (DED) operation and/or a steel metal powder DED operation, wherein the steel wire and/or the steel metal powder comprises 0.10-0.50 wt % of carbon and 0.50-1.20 wt % of boron.

2. The method according to claim 1, wherein the steel wire and/or steel metal powder comprises carbon and boron as hardening mechanisms.

3. (canceled)

4. The method according to claim 1, wherein the steel wire is a stainless steel wire and/or the steel metal powder is a stainless steel metal powder.

5. The method according to claim 1, wherein the step of applying the load carrying surface includes applying more than one layer by use of DED.

6. The method according to claim 1, wherein during the step of applying a load carrying surface, an application speed is varied during application of the steel wire material and/or the steel metal powder on the metallic ring member.

7. The method according to claim 6, wherein the application speed is varied by decreasing the speed at least one time during the step of applying the load carrying surface.

8. The method according to a claim 1, wherein a final radial thickness of the applied load carrying surface is 0.25 mm-10 mm.

9. The method according to claim 1, further comprising a step of: prior to the step of applying the load carrying surface, removing an existing load carrying surface of the metallic ring member

10. A rolling or plain bearing ring for a rolling or plain bearing, wherein the rolling or plain bearing ring has been manufactured by the method according claim 1.

11. The method according to claim 5, wherein the step of applying the load carrying surface includes applying 2-20 layers by use of DED.

12. The method according to claim 9, wherein the step of removing an existing load carrying surface includes removing a radial thickness of a material of the metallic ring member, the radial thickness having a value of 0.25 mm-10 mm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention will hereinafter be further explained by means of non-limiting examples with reference to the appended schematic figures where;

[0031] FIG. 1 is a cross-sectional view of a rolling or plain bearing ring according to an example embodiment of the present invention;

[0032] FIG. 2 is a schematic side view of a rolling bearing according to the invention;

[0033] FIG. 3 is a cross-sectional view of a rolling or plain bearing ring according to an example embodiment of the present invention; and

[0034] FIG. 4 is a flowchart of a method according to an example embodiment of the present invention.

[0035] It should be noted that the drawings have not necessarily been drawn to scale and that the dimensions of certain features may have been exaggerated for the sake of clarity.

DETAILED DESCRIPTION OF EMBODIMENTS

[0036] FIG. 1 depicts a cross-sectional view of a rolling or plain bearing ring 1 according to an example embodiment of the present invention. The cross-sectional view is defined by a plane which extends along a rotational axis A of the rolling or plain bearing ring 1. The rolling or plain bearing ring 1 comprises a metallic ring member 1, which in the shown embodiment is a steel ring. It further comprises a load carrying surface 11 provided on the metallic ring member 1. The load carrying surface 11 has been applied onto the metallic ring member 1 by a DED operation according to an example embodiment of the method as disclosed herein.

[0037] The load carrying surface 11 is here a raceway surface, such as a raceway surface for rolling elements, i.e. balls and/or rollers. As shown, the raceway surface 11 may have a spherical shape. Thereby, the rolling or plain bearing ring 1 may be able to be misaligned relative an outer ring 2 (see FIG. 2). As such, a rolling or plain bearing 10, such as the rolling bearing shown in FIG. 2, which comprises the rolling or plain bearing ring 1, may be able to accommodate shaft deflections during use.

[0038] Accordingly, FIG. 2 depicts a side view of a rolling bearing 10 which comprises the rolling bearing ring 1 as e.g. shown in FIG. 1. The rolling bearing ring 1 is here an inner ring of the rolling bearing 10. The rolling bearing 10 further comprises the above-mentioned outer ring 2 and a plurality of rolling elements 3 which are provided in-between the outer ring 2 and the rolling bearing ring 1. It shall be understood that the outer ring 2 may alternatively or additionally be provided with a load carrying surface according to the invention.

[0039] FIG. 3 depicts a cross-sectional view of a portion of a rolling or plain bearing ring 1 according to an embodiment of the invention. It comprises a load carrying surface 11 and a metallic ring member 1, wherein the load carrying surface 11 has been applied by DED according to an example embodiment of the invention. The load carrying surface has a radial thickness h.sub.1, which may be 0.25-10 mm. The radial direction of the ring 1 is perpendicular to and intersects the rotational axis A of the rolling or plain bearing ring 1. The metallic ring member 1 has a radial thickness h.sub.2 which is substantially larger than the radial thickness h.sub.1, such as 10-500 mm.

[0040] In FIG. 4 a flowchart of a method according to an example embodiment of the invention is shown. The method is a method for manufacturing a rolling or plain bearing ring 1, such as the rings 1 shown in FIGS. 1-3.

[0041] The method comprises: [0042] S1: providing a metallic ring member 1; and [0043] S2: applying a load carrying surface 11 onto the metallic ring member 1 by use of a steel wire Directed Energy Deposition (DED) operation and/or a steel metal powder DED operation. For example, the DED operation may be a laser cladding operation.

[0044] The steel wire and/or steel metal powder which is applied onto the metallic ring member 1 preferably comprises C and B as hardening mechanisms, thereby forming carbides and borides in the applied steel material. For example, as mentioned in the above, the steel wire and/or steel metal powder may comprise 0.10-0.50 wt % of C and 0.50-1.20 wt % of B, such as 0.15-0.30 wt % of C and 0.60-0.90 wt % of B. It has been found that a larger wt % of C may increase the risk of cracking in the load carrying surface 11. As such, by having a lower amount of C and a higher amount of B, a sufficient surface hardness can be achieved, such as more than 55 HRC, with a reduced risk of inducing cracks in the load carrying surface 11.

[0045] The steel wire and/or steel metal powder which is used for forming the load carrying surface 11 may be a stainless steel wire and/or stainless steel metal powder, respectively, thereby providing a corrosion resistant surface 11. For example, a corrosion resistant load carrying surface may thereby be provided on a large rolling or plain bearing ring 1 in a cost-effective manner.

[0046] Preferably, applying the load carrying surface 11 comprises applying more than one layer by use of DED, such as 2-20 layers.

[0047] Still further, the application speed may be varied during application of the steel wire material and/or steel metal powder on the metallic ring member 1. For example, the speed may be varied by decreasing the speed at least one time during the application of the load carrying surface 11. Thereby, a thin layer may first be provided on the ring 1, followed by one or more thicker layers when the application speed is reduced, until e.g. a final radial thickness h.sub.1 of 0.25-10 mm is achieved.

[0048] The method may further comprise an optional step S12 (indicated by a box with a dashed line). The step S12 comprises: [0049] prior to applying the load carrying surface 11, removing an old load carrying surface of the metallic ring member 1, such as removing 0.25-10 mm of material from the metallic ring member 1, as seen in a radial direction of the metallic ring member 1. Accordingly, the present invention may be a method for remanufacturing an already used rolling or plain bearing ring 1.

[0050] The powder fraction of the steel metal powder may be 30-200 ?m.

[0051] Furthermore, step S2 may be followed by a subsequent step of machining the applied load carrying surface 11, such as grinding and/or honing.

[0052] The load carrying surface 11 of the rolling or plain bearing ring 1 as shown in e.g. FIG. 1 has a varying radius, as seen in the cross-sectional view. In this embodiment, the radius is varying such that a spherical outer profile is formed. According to an example embodiment, the rotational speed of the metallic ring member 1 during the DED step is varied such that a constant surface speed is achieved. Thereby a surface layer 11 with a uniform thickness can be obtained.

[0053] It is to be understood that the present invention is not limited to the embodiments described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the appended claims.