PLAIN BEARINGS, ESPECIALLY FOR A GEARBOX OF A WIND TURBINE

Abstract

A sliding bearing (22), in particular for a gearbox of a wind turbine, with a support body (27) which is designed as a bushing (35) rolled from a support body strip (32), wherein a first longitudinal end (33) and a second longitudinal end (34) of the support body strip (32) are joined together at a joint (23) by a material bond, in particular by a welded joint, and a sliding layer (30) applied to the support body (27), on which a sliding surface (17) is formed, wherein the sliding surface (17) is formed on an outer surface (16) of the sliding bearing (22), wherein a lubricant distribution groove (19) extending in an axial direction (31) of the sliding surface (17) is formed on the sliding surface (17), wherein the joint (23) is formed in the region of the lubricant distribution groove (19), characterized in that the lubricant distribution groove (19) is formed by a recess in the form of a flattening is formed,wherein the lubricant distribution groove (19) has a groove base (36) which extends into the outer surface (16) of the sliding bearing (22).

Description

[0001] The invention relates to a planetary gear unit and a wind turbine equipped with the planetary gear unit.

[0002] A planetary gear of this type is known, for example, from WO 2011127509 A1 of the same applicant.

[0003] Another planetary gear of this type is known from EP 2 383 480 B1. The planetary gear known from EP 2 383 480 B1 has the disadvantage that the plain bearings of the planetary gear are complex to manufacture.

[0004] EP 3 396 187 A1 discloses a method for manufacturing a sliding bearing bushing according to which a flat support metal layer is provided, a sliding layer is arranged on this support metal layer to produce a flat composite material, and then the flat composite material is rolled into the shape of the sliding bearing bushing in such a way that the support metal layer is arranged radially below the sliding layer in the sliding bearing bushing.

[0005] Other plain bearing bushings are known from JP 2002- 195 261 A, JP 2017- 48 849 A, US 2012 / 0 148 179 A1 and JP 2015- 178 865 A.

[0006] The object of the present invention was to overcome the disadvantages of the prior art and to provide a planetary gearbox for a wind turbine with increased reliability.

[0007] This problem is solved by a device and a method according to claims 1 and 7.

[0008] Plain bearing, in particular for a gearbox of a wind turbine, comprising a support body and a sliding layer applied to the support body, on which a sliding surface is formed, wherein a lubricant distribution groove extending in an axial direction of the sliding surface is formed on the sliding surface. The support body is designed as a bushing rolled from a support body strip, wherein a first longitudinal end and a second longitudinal end of the support body strip are materially bonded to each other at a joint, in particular by a welded joint, wherein the joint is formed in the area of ​​the lubricant distribution groove.

[0009] The plain bearing according to the invention offers the advantage that the lubricant distribution groove can, at least partially, serve to expose the joint. This measure increases the sliding surface area of ​​the plain bearing, thereby reducing wear. Furthermore, the surprising advantage arises that the plain bearing according to the invention exhibits particularly good sliding properties, since a uniform lubricating film can build up over the sliding surface. In contrast, in conventional plain bearings, the joint is often offset from the lubricant distribution groove in the circumferential direction, resulting in poorer lubrication of the bearing.

[0010] Furthermore, it can be advantageous for a lubricating oil bore to open into the lubricant distribution groove. The lubricant distribution groove can be supplied with lubricating oil via this lubricating oil bore.

[0011] Furthermore, the sliding surface is formed on an outer surface of the sliding bearing, with the lubricant distribution groove being formed by a recess in the form of a flattened area. Such a sliding bearing is easy to manufacture and also exhibits good sliding properties.

[0012] Furthermore, it can be provided that the joint has a clearance along the entire axial extent of the plain bearing, and that the lubricant distribution groove extends only over a portion of the axial extent of the plain bearing. These measures ensure that the lubricant distribution groove is centrally located with respect to the axial extent of the plain bearing, thus allowing the lubricating oil to collect within it. Particularly when a clearance is necessary in the joint area of ​​the plain bearing anyway, it is surprisingly advantageous for the sliding properties of the plain bearing if the clearance coincides with the lubricant distribution groove.

[0013] Another advantageous design allows the lubricant distribution groove to have a maximum depth and the sliding layer to have a layer thickness, where the maximum depth of the lubricant distribution groove is equal to or less than the layer thickness of the sliding layer. This allows the lubricant distribution groove to simultaneously serve as a clearance for the joining point of the support body.

[0014] According to further training, it is possible for the recess to have a maximum depth, whereby the maximum depth of the recess is less than the maximum depth of the lubricant distribution groove. This measure ensures that the lubricating oil collected in the lubricant distribution groove can escape axially through the recess in the smallest possible quantities.

[0015] According to the invention, a planetary gearbox for a wind turbine is provided, comprising at least one plain bearing, in particular a radial planetary gear bearing. The plain bearing is designed according to one of the preceding claims.

[0016] The invention also provides a method for manufacturing a plain bearing, in particular for a gearbox of a wind turbine. The plain bearing comprises a support body and a sliding layer applied to the support body, on which a sliding surface is formed, wherein a lubricant distribution groove extending in an axial direction is formed on the sliding surface. The method comprises the following process steps: - Providing a support body strip with a first longitudinal end and a second longitudinal end; - Rolling the support body strip into a bushing, which forms the support body; - Material-bonded joining of the first longitudinal end and the second longitudinal end of the support body strip at a joint; - Introducing the lubricant distribution groove into the sliding layer, wherein the lubricant distribution groove is arranged at a point on the sliding bearing where the joint is formed.

[0017] The inventive method offers the surprising advantage that a particularly advantageous sliding bearing can be produced by the inventive method steps.

[0018] Furthermore, it may be provided that the sliding layer or parts thereof are applied to the still flat support body strips, in particular that the sliding layer is applied to the support body strips by roller cladding.

[0019] According to a particular design, it is possible that the lubricant distribution groove and / or the clearance of the joint is produced by mechanical processing, in particular by milling.

[0020] Furthermore, it can be provided that the axial extent of the lubricant distribution groove is between 50% and 100%, in particular between 60% and 95%, preferably between 70% and 80% of the axial extent of the sliding bearing.

[0021] Furthermore, it can be provided that the maximum depth of the cutout is between 0.01 mm and 3 mm, in particular between 0.05 mm and 1 mm, preferably between 0.1 mm and 0.5 mm.

[0022] Furthermore, it can be provided that the maximum depth of the lubricant distribution groove is between 0.1 mm and 7 mm, in particular between 0.5 mm and 5 mm, preferably between 1 mm and 3 mm.

[0023] This document assumes lubricating oil as the lubricant. However, it is standard practice for those skilled in the art to use other lubricants, such as grease, in the present planetary gear or plain bearing design, and therefore the scope of protection is not limited to the use of a specific lubricant.

[0024] To better understand the invention, it is explained in more detail with reference to the following figures.

[0025] They each show, in a highly simplified, schematic representation: Fig. 1 a sectional view of a design variant of a planetary gear; Fig. 2 a perspective view of a first embodiment of a sliding bearing in a first view; Fig. 3 a perspective view of a first embodiment of a sliding bearing in a second view; Fig. 4 a section view according to the section line IV-IV from Fig. 2; Fig. 5 A schematic representation of the sequence of individual manufacturing steps for the production of the plain bearing.

[0026] It should be noted at the outset that in the differently described embodiments, identical parts are provided with the same reference numerals or component designations, and the disclosures contained in the entire description can be applied analogously to identical parts with the same reference numerals or component designations. Furthermore, the positional designations chosen in the description, such as top, bottom, side, etc., refer to the figure directly described and illustrated, and these positional designations must be applied analogously to the new position if the position changes.

[0027] Fig. Figure 1 shows an embodiment of a planetary gear 1 in a sectional view according to a cross-section along a centerline 2 of the planetary gear 1. The view according to Fig. Figure 1 is shown schematically and serves to explain the general structure of the planetary gear and to illustrate the parts used in a planetary gear.

[0028] As is well known, wind turbines comprise a tower at the top of which a nacelle is located, housing the rotor with its rotor blades. This rotor is operatively connected via planetary gear 1 to a generator, which is also located in the nacelle. The planetary gear 1 converts the low rotational speed of the rotor into a higher rotational speed of the generator rotor. Since such wind turbine designs represent the state of the art, the reader is referred to the relevant literature on this subject.

[0029] The planetary gear set 1 has a sun gear 3 which is motionally coupled to a shaft 4 leading to the generator rotor. The sun gear 3 is surrounded by several planet gears 5, for example two, preferably three. Both the sun gear 3 and the planet gears 5 have external spur gears which mesh with each other, wherein these spur gears are arranged in Fig. 1 are shown schematically.

[0030] The planet gears 5 are each mounted in a planet carrier 7 by means of a planet gear pin 6. Furthermore, the planet gear pin 6 may be fixed or received in a force-fit or form-fit manner in a first planet carrier web 8 and a second planet carrier web 9. In particular, the planet gear pin 6 may be secured against rotation by an arbitrary locking element (not explicitly shown). The two planet carrier webs 8 and 9 are part of the planet carrier 7.

[0031] Surrounding the planet gears 5 is a ring gear 10, which has internal teeth that mesh with the spur teeth of the planet gears 5. The ring gear 10 can be formed in, or coupled to, a one-piece or multi-piece planetary gear housing 11.

[0032] Furthermore, it may be provided that at least one planet carrier radial sliding bearing 12 is arranged in the planetary gear housing 11, which serves to support the planet carrier 7 in the planetary gear housing 11.

[0033] In particular, it may be provided that an oil distribution channel section 13 is formed in the first planet carrier cheek 8, by means of which the individual sliding surfaces 17 of the individual sliding bearings 12, 14, 21 can be supplied with lubricating oil.

[0034] Furthermore, it may be provided that at least one planet gear radial sliding bearing 14 is provided for each planet gear 5 to support the planet gears 5 on the planet gear bolts 6.

[0035] According to a first embodiment, the planetary gear radial bearing 14 is attached to the planetary gear bolt 6 on an inner surface 15. A sliding surface 17 is formed on an outer surface 16 of the planetary gear radial bearing 14. Furthermore, a lubricating oil bore 18 can be provided in the planetary gear radial bearing 14, which leads from the inner surface 15 of the planetary gear radial bearing 14 to the outer surface 16 of the planetary gear radial bearing 14.

[0036] Furthermore, it can be provided that at least one lubricant distribution groove 19 is formed on the outer surface 16 of the planetary gear radial bearing 14, which is fluid-coupled with the lubricating oil bore 18 in the planetary gear radial bearing 14. In particular, it can be provided that two lubricating oil bores 18 and two lubricant distribution grooves 19 are formed diametrically opposite each other on the planetary gear radial bearing 14. A detailed embodiment of the planetary gear radial bearing 14 will be described below. Fig. 2 described in more detail.

[0037] As also from Fig. As can be seen in Figure 1, it may be provided that oil distribution channel sections 20 are formed in the planet gear bolt 6, which open into the lubricating oil bores 18 of the planet gear radial sliding bearings 14.

[0038] What happens next? Fig. As can be seen in Figure 1, a sun gear radial bearing 21 may be provided, which serves to support the shaft 4 on which the sun gear 3 is mounted. In particular, it may be provided that the first sun gear radial bearing 21 is arranged between a cavity of the first planet carrier web 8 and the shaft 4.

[0039] In the Fig. 2 and Fig. Figure 3 shows a further and possibly independent embodiment of the sliding bearing 22, whereby the same reference numerals or component designations are used for identical parts as in the preceding figure. Fig. 1. To avoid unnecessary repetition, reference is made to the detailed description in the preceding section. Fig. 1. (Reference is made to the above.)

[0040] The Fig. Figure 2 shows a first embodiment of the sliding bearing 22 in a first perspective view from its front side.

[0041] The Fig. Figure 3 shows the first embodiment of the sliding bearing 22 in a second perspective view from its rear side.

[0042] In a gearbox for wind turbines, in particular in the planetary gearbox 1, the planet carrier radial bearing 12 and / or the planet gear radial bearing 14 and / or the sun gear radial bearing 21 can be used in Fig. 2 have the structure described. Of course, other plain bearings not installed in a wind turbine can also have the structure according to the invention. For the sake of simplicity, all plain bearings that can have the structure according to the invention will therefore be generally referred to as plain bearing 22 in this document. The one described in Fig. The described design of the plain bearing 22 can be used in particular for the planetary gear radial plain bearing 14. Therefore, the planetary gear radial plain bearing 14 is described in detail, although it should be noted that the design according to the invention can be implemented analogously for all plain bearings 22, in particular plain bearings 22 used in a gearbox for wind turbines.

[0043] As from the Fig. 2 and Fig. As can be seen in Figure 3, the plain bearing 22 may have two lubricant distribution grooves 19 diametrically opposed on its outer surface 16. Of course, there may be only one lubricant distribution groove 19 or a larger number of lubricant distribution grooves 19 on the plain bearing 22, which may be arranged evenly or unevenly distributed around the circumference.

[0044] Furthermore, it can be provided that the lubricating oil bores 18 each open into the lubricant distribution groove 19. The lubricating oil bores 18 serve to convey lubricating oil from the inner surface 15 of the sliding bearing 22 to the outer surface 16 of the sliding bearing 22.

[0045] As especially from Fig. As can be seen in Figure 2, the sliding bearing 22 can be designed as a rolled element which is connected at a joint 23 by means of a material-bonded connection and thus forms a bushing. The material-bonded connection of the joint 23 can be achieved, for example, by a welding process.

[0046] Laser welding, for example, can be used as a welding process. In particular, it can be provided that in one process step, the side of the joint 23 on which the support body 27 is formed is welded. The energy input from the laser beam can be selected such that only the material of the support body 27, especially steel, is melted, preventing any mixing of the melt with the material of the bearing metal layer 28. In a further process step, the side of the joint 23 on which the bearing metal layer 28 is formed can be welded, in order to weld it as well. Here, too, the energy input from the laser beam can be selected such that only the material of the bearing metal layer 28 is melted, preventing any mixing of the melt with the material of the support body 27. This results in a joint 23 with surprisingly high strength.The described procedure can of course be applied to both those plain bearings 22 in which the support body 27 forms the innermost layer and those plain bearings 22 in which the support body 27 forms the outermost layer.

[0047] In another design variant, electron beam welding can also be used as the welding process. Naturally, the methodology described above can also be used with this welding process.

[0048] Alternatively, it is also conceivable that the material-bonded connection at joint 23 is created by a soldering process.

[0049] As from Fig. 2 further shown, it can be provided that a clearance 24 is formed in the area of ​​the joining point 23, by which it can be ensured that any protrusions of the weld produced by the joining process do not extend into a cylinder of the sliding surface 17 and thus the sliding properties of the sliding bearing 22 are not impaired.

[0050] As from Fig. As can be seen in Figure 2, the lubricant distribution groove 19 is designed to be formed in the area of ​​the joint 23. This ensures that the necessary clearance 24 and the lubricant distribution groove 19 coincide, at least partially. This simplifies the manufacturing process of the plain bearing 22.

[0051] As from Fig. As further shown in Figure 2, the clearance 24 can extend over the entire axial extent 25 of the sliding bearing 22. The axial extent 26 of the lubricant distribution groove 19 can be less than the axial extent 25 of the sliding bearing 22. In particular, the lubricant distribution groove 19 can be arranged centrally on the sliding bearing 22 with respect to its axial extent 25. Furthermore, the lubricating oil bore 18 can also be arranged centrally on the sliding bearing 22 with respect to its axial extent 25. As shown in the exemplary embodiment according to Figure 2, the lubricating oil bore 18 can be arranged centrally on the sliding bearing 22 with respect to its axial extent 25. Fig. As can be seen in Figure 2, the lubricating oil bore 18 can be arranged centrally in the lubricant distribution groove 19, also when viewed circumferentially. Furthermore, the joining point 23 can be arranged centrally to the lubricant distribution groove 19 when viewed circumferentially.

[0052] In a further embodiment not shown, the lubricating oil bore 18 and / or the joining point 23 can also be arranged circumferentially centered on the outside of the lubricant distribution groove 19. This makes it possible, for example, to arrange the lubricating oil bore 18 not in the area of ​​the joining point 23, but next to it.

[0053] As from the Fig. 2 and Fig. As can be seen further in Figure 3, the lubricant distribution groove 19 extends in an axial direction 31. The joining point 23 also extends in an axial direction 31.

[0054] In the Fig. Figure 4 shows a detailed view of the sliding bearing 22 in section IV-IV, where the same reference numerals or component designations are used for identical parts as in the preceding figures. Fig. 1 to 3 are used. To avoid unnecessary repetition, reference is made to the detailed description in the preceding section. Fig. 1 to 3 were indicated or referenced.

[0055] As from Fig. As can be seen in Figure 4, the sliding bearing 22 can be provided to comprise a support body 27, a bearing metal layer 28, and a polymer layer 29. The sliding surface 17 can be formed on the polymer layer 29.

[0056] The support body 27 preferably consists of a metallic material, usually steel, but can also consist of a material that can perform the same or a similar function, namely providing the mechanical strength of the sliding bearing 22. For example, various copper alloys, such as brass or bronze, can also be used.

[0057] The bearing metal layer 28 is formed by a bearing metal alloy. Such bearing metal alloys are known from the prior art. For example, the bearing metal alloy can be formed by an alloy based on tin, bismuth, indium, lead or aluminum, as well as alloys based on, optionally high-lead, CuPb or on AlSn or AlBi.

[0058] Although in Fig. While the plain bearing 22 is shown as a three-layer bearing element in Figure 1, it can also have fewer or more than three layers. For example, the polymer layer 29 can be applied directly to the support body 27. Likewise, conventional intermediate layers, such as at least one bonding layer or at least one diffusion barrier layer, can be arranged as needed. This bonding layer can be arranged between the support body 27 and the bearing metal layer 28 and / or between the bearing metal layer 28 and the polymer layer 29. This diffusion barrier layer can be arranged between the support body 27 and the bearing metal layer 28 and / or between the bearing metal layer 28 and the polymer layer 29.

[0059] For the sake of simplicity, the layer structure applied to the support body 27, which may, for example, include the bearing metal layer 28 and the polymer layer 29, is referred to as the sliding layer 30.

[0060] The polymer layer 29 can contain solid lubricant particles and metal oxide particles and can consist exclusively of a polyimide polymer or a polyamide-imide polymer, or preferably of these components.

[0061] The polyimide polymer may, for example, be selected from a group comprising or consisting of polyimide (PI), polysuccinimide (PSI), polybismaleimide (PBMI), polybenzimidazole (PBI), polyoxadiazobenzimidazole (PBO) and polyimide sulfone (PISO), as well as mixtures thereof.

[0062] Preferably, the polymer is a polyamide imide. The polyamide imide may contain at least partially aromatic groups; preferably, it is a fully aromatic polyamide imide.

[0063] In Fig. Section 5 schematically illustrates the individual process steps for manufacturing the plain bearing 22. As shown from Fig. As can be seen in Figure 5, it can be provided that a support strip 32 is supplied, which has a first longitudinal end 33 and a second longitudinal end 34. In a first embodiment, the support strip 32 can already have the sliding layer 30 applied to it. The sliding layer 30 can, for example, be applied to the support strip 32 by roller plating.

[0064] In another embodiment variant, it can also be provided that the sliding layer 30 is applied only to the finished rolled support body 27.

[0065] As from Fig. As can be seen in Figure 5, it can be provided that the support strip 32 is rolled into a bushing 35 by means of a rolling process, whereby the first longitudinal end 33 and the second longitudinal end 34 of the support strip 32 are brought close together. In the finished rolled bushing 35, the first longitudinal end 33 and the second longitudinal end 34 can be in contact with each other or be a short distance apart, so that the two longitudinal ends 33, 34 can be joined together at the joint 23 in a material-locking manner.

[0066] In a variant embodiment where the sliding layer 30 is already applied to the support strip 32, it can be provided that the sliding layer 30 is removed in the area of ​​the longitudinal ends 33, 34 either on the flat support strip 32 or only when the bushing 35 is rolled in, so that the longitudinal ends 33, 34 of the support strip 32 are freely accessible for a material-bonded connection. This process step can optionally be omitted.

[0067] In a further process step, the first longitudinal end and the second longitudinal end 33, 34 of the support body strip 32 can then be welded together at the joint 23. In a subsequent process step, the recess 24 can be created by mechanical removal, in particular by milling. Specifically, the protruding material of the weld seam is removed in the recess 24.

[0068] If, as described above, the sliding layer 30 has already been sufficiently removed before welding the two longitudinal ends 33, 34 of the support body strip 32, this can optionally subsequently act as a clearance 24, meaning that no further processing step is necessary after the welding process.

[0069] In a further processing step, the lubricant distribution groove 19 can be created by mechanical removal, in particular by milling.

[0070] As from Fig. As can be seen in Figure 4, the lubricant distribution groove 19 is designed to have a groove base 36 which extends into the outer surface 16 of the sliding bearing 22. In such a design, a wedge gap 37 forms at the edge of the lubricant distribution groove 19 when viewed circumferentially.

[0071] In a non-inventive embodiment, it can of course also be provided that the groove base 36 of the lubricant distribution groove 19 does not extend into the outer surface 16, but that the lubricant distribution groove 19 is formed in the form of a recess and that the groove base 36 is thus limited in the circumferential direction by side walls. The lubricant distribution groove 19 has a maximum depth 38, which is measured from a cylindrical section of the outer surface 16. The maximum depth 38 of the lubricant distribution groove 19 can extend over a layer thickness 39 of the sliding layer 30. The width 40 of the lubricant distribution groove 19 is determined by the diameter of the outer surface 16 and the maximum depth 38 of the lubricant distribution groove 19.

[0072] The recess 24 has a maximum depth 41, which is also measured from the outer cylinder of the outer surface 16 to a groove base 42 of the recess 24. As shown Fig. As can be seen in Figure 4, it may be provided that, viewed in the circumferential direction, a first clearance groove wall 44 or a second clearance groove wall 45 are formed, which create a transition between the groove base 42 of the clearance 24 and the outer surface 16 of the sliding bearing 22. This is the case when the maximum depth 41 of the clearance 24 is chosen to be so large in relation to the width 43 of the clearance 24 that the groove base 42 of the clearance 24 cannot extend into the outer surface 16 of the sliding bearing 22.

[0073] As from Fig. As can be seen in Figure 4, it can be provided that the maximum depth 38 of the lubricant distribution groove 19 is greater than the maximum depth 41 of the clearance 24. The maximum depth 41 of the clearance 24 is chosen to be as small as possible so that during the use of the sliding bearing 22, as little as possible of the lubricant directed into the lubricant distribution groove 19 can escape axially via the clearances 24.

[0074] As from Fig. As can be further seen in section 4, it may be provided that the width 40 of the lubricant distribution groove 19 is larger than the width 43 of the clearance 24.

[0075] In another embodiment, not shown, it is of course also possible for the sliding surface 17 and thus also the lubricant distribution grooves 19 to be arranged on the inner surface 15 of the sliding bearing 22. It is within the skill of a person skilled in the art to modify the design of the sliding bearing accordingly, based on the described embodiment.

[0076] Finally, for the sake of clarity, it should be noted that, for a better understanding of the structure, some elements have been shown not to scale and / or enlarged and / or reduced in size.

Claims

[1] Plain bearing (22), in particular for a gearbox of a wind turbine, with a support body (27) which is designed as a bushing (35) rolled from a support body strip (32), wherein a first longitudinal end (33) and a second longitudinal end (34) of the support body strip (32) are joined together at a joint (23) by a material bond, in particular by a welded joint, and a sliding layer (30) applied to the support body (27), on which a sliding surface (17) is formed, wherein the sliding surface (17) is formed on an outer shell surface (16) of the plain bearing (22), wherein a lubricant distribution groove (19) extending in an axial direction (31) of the sliding surface (17) is formed on the sliding surface (17), wherein the joint (23) is formed in the region of the lubricant distribution groove (19), characterized by, that the lubricant distribution groove (19) is formed by a recess in the form of a flattening, wherein the lubricant distribution groove (19) has a groove base (36) which extends into the outer shell surface (16) of the sliding bearing (22). [2] Plain bearing (22) according to claim 1, characterized by , that a lubricating oil bore (18) opens into the lubricant distribution groove (19). [3] Plain bearing (22) according to one of the preceding claims, characterized by , that the joining point (23) has a clearance (24) over the entire axial extent (25) of the sliding bearing (22) and an axial extent (26) of the lubricant distribution groove (19) extends only over a partial section of the axial extent (25) of the sliding bearing (22). [4] Plain bearing (22) according to one of the preceding claims, characterized by, that the lubricant distribution groove (19) has a maximum depth (38) and the sliding layer (30) has a layer thickness (39), wherein the maximum depth (38) of the lubricant distribution groove (19) is equal to or less than the layer thickness (39) of the sliding layer (30). [5] Plain bearing (22) according to any one of the preceding claims, characterized by , that the clearance (24) has a maximum depth (41), wherein the maximum depth (41) of the clearance (24) is less than the maximum depth (38) of the lubricant distribution groove (19). [6] Planetary gear (1) for a wind turbine, comprising at least one plain bearing (22), in particular a planet gear radial plain bearing (14), characterized by that the sliding bearing (22) is designed according to one of the preceding claims. [7] Method for manufacturing a plain bearing (22), in particular for a gearbox of a wind turbine, wherein the plain bearing (22) comprises a support body (27) and a sliding layer (30) applied to the support body (27), on which a sliding surface (17) is formed, wherein the sliding surface (17) is formed on an outer shell surface (16) of the plain bearing (22), wherein a lubricant distribution groove (19) extending in an axial direction (31) is formed on the sliding surface (17), comprising the process steps: - Providing a support body strip (32) with a first longitudinal end (33) and a second longitudinal end (34); - Rolling of the support body strip (32) to a bushing (35) which forms the support body (27); - Material-bonded joining of the first longitudinal end (33) and the second longitudinal end (34) of the support body strip (32) at a joint (23); - Introducing the lubricant distribution groove (19) into the sliding layer (30), wherein the lubricant distribution groove (19) is arranged at a location on the sliding bearing (22) where the joining point (23) is formed, characterized by , that the lubricant distribution groove (19) is formed by a recess in the form of a flattening, wherein the lubricant distribution groove (19) has a groove base (36) which extends into the outer shell surface (16) of the sliding bearing (22). [8] Method for manufacturing a sliding bearing (22) according to claim 7, characterized by , that the sliding layer (30) or parts thereof is applied to the still flat support body strip (32), in particular that the sliding layer (30) is applied to the support body strip (32) by roller cladding. [9] Method for manufacturing a sliding bearing (22) according to claim 7 or 8, characterized by, that the lubricant distribution groove (19) and / or the clearance (24) of the joint (23) is produced by mechanical processing, in particular by milling.

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