Manufacturing method of sliding bearing

Abstract

The invention provides a manufacturing method of a sliding bearing, and belongs to the technical field of bearing manufacturing methods. When the sliding bearing is manufactured, firstly, a metal plate is rolled and welded to form the cylindrical base body layer, or a metal round pipe is directly blanked to form the base body layer, and then the working layer is applied to the inner surface or the outer surface of the base body layer through the additive manufacturing technology. Wherein the selectable range of the metal plate is wide, the needed size is easy to obtain, and by selecting the metal plate with machining allowance, after welding is completed, the ovality of the base body layer can be corrected in a machining mode. The working layer does not need to be rolled and welded after being applied, so that the surface of the working layer can be prevented from being crushed or indented, and the influence on the performance of the working layer is avoided.

Description

Technical Field

[0001] The invention relates to a method for manufacturing a sliding bearing, and belongs to the technical field of methods for manufacturing bearings. Background Art

[0002] Compared with rolling bearings, sliding bearings have the advantages of compact structure and high reliability. Using sliding bearings instead of rolling bearings under low-speed and heavy-load conditions of wind power generation equipment has obvious cost advantages. For example, the wind power gearbox planetary gear sliding bearing disclosed in the Chinese utility model patent with authorization announcement number CN217481930U includes a planetary gear carrier and a planetary shaft fixed on the planetary carrier. The planetary shaft and the planetary gear are matched through sliding bearings, wherein the sliding bearing has an interference fit with the planetary gear and has a radial clearance with the planetary shaft. In the prior art, there are also sliding bearings that have an interference fit with the planetary shaft and have a movable clearance with the planetary gear.

[0003] At present, the common sliding bearing structure used for the planetary gear of the gearbox of wind power generation equipment is a sliding bearing bushing formed by rolling a composite metal plate and pressed into the planetary gear hole or pressed on the planetary shaft. For example, the Chinese invention patent application with application publication number CN1712749A discloses a preparation method of a wear-resistant self-lubricating sliding bearing of a polytetrafluoroethylene composite material. The preparation method includes sintering a layer of bronze powder as an intermediate layer on the surface of a steel plate (i.e., a metal plate), rolling a polymer layer (i.e., a sliding layer) containing carbon fibers treated with a rare earth modifier on the intermediate layer, and then sintering, machining modification, and rolling welding under nitrogen protection conditions to make a composite sliding bearing.

[0004] The above-mentioned preparation method is to first obtain a three-layer composite plate including a metal plate, an intermediate layer and a sliding layer, and then perform rolling and welding, wherein the metal plate forms the base layer of the sliding bearing after forming. In order to ensure the use effect of the sliding bearing, the ovality of the sliding bearing must be controlled, and the use of rolling and welding processes can easily cause ovality to exceed the tolerance. Usually, the ovality is corrected by machining after rolling and welding, but machining will remove the sliding layer and the intermediate layer, which will destroy the original structure of the composite plate and affect the use performance of the sliding bearing. At the same time, the material of the intermediate layer and the sliding layer (collectively referred to as the working layer) is softer than the base layer, and it is easy to produce bruises or indentations during the rolling process, which will also affect the use performance of the sliding bearing. In addition, the welding process will affect the performance of the working layer (especially the sliding layer) at the joint position. Summary of the invention

[0005] The purpose of the present invention is to provide a method for manufacturing a sliding bearing to solve the problem that in the prior art, a composite plate is first prepared, and then rolled and welded to prepare the sliding bearing, which results in the surface of the softer working layer being easily crushed or indented during the rolling process and the performance of the working layer at the joint position being affected during the welding process.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions: A method for manufacturing a sliding bearing comprises the following steps: firstly, a metal plate is rolled and welded to form a cylindrical base layer, or a metal round tube is directly cut to form the base layer, and then a working layer is applied to the inner surface or outer surface of the base layer by an additive manufacturing process.

[0007] The beneficial effect of the above technical solution is that: the present invention is a pioneering invention. When manufacturing a sliding bearing, the present invention first rolls and welds a metal plate into a cylindrical base layer, or directly cuts a metal round tube to obtain the base layer, and then applies a working layer on the inner surface or outer surface of the base layer by an additive manufacturing process. Since the base layer already has a cylindrical shape through rolling welding or round tube cutting, the working layer subsequently applied on the inner surface or outer surface of the base layer by the additive manufacturing process forms a sliding bearing together with the base layer. If the working layer is applied to the inner surface of the base layer, the sliding bearing has an interference fit with the planetary gear, and there is a gap between the working layer and the planetary shaft, and the working layer has a sliding friction fit with the planetary shaft; if the working layer is applied to the outer surface of the base layer, the sliding bearing has an interference fit with the planetary shaft, and there is a gap between the working layer and the planetary gear, and the working layer has a sliding friction fit with the planetary gear. No matter how the base layer is formed, and no matter whether the working layer is applied to the inner surface or the outer surface of the base layer, the working layer does not need to be rolled again, which can avoid bruises or indentations on the surface of the working layer. At the same time, the working layer does not need to be welded again, which can avoid affecting the performance of the working layer.

[0008] Furthermore, the working layer includes a metal layer and a sliding layer. During manufacturing, the metal layer is first applied to the inner surface or outer surface of the base layer by an additive manufacturing process, and then the sliding layer is applied to the surface of the metal layer by an additive manufacturing process.

[0009] Furthermore, before applying the sliding layer, the surface of the metal layer is firstly trimmed to form a curved surface with a convex middle portion in the axial direction, and then when applying the sliding layer, the wall thickness of the sliding layer is ensured to be uniform to obtain a sliding layer with a convex surface.

[0010] Furthermore, the thickness of the metal layer is 1-3 mm, and the shaping amount is between 0.5-1 mm.

[0011] Furthermore, the base layer is made of a metal plate through rolling and welding, and after being made, the inner and outer surfaces and end faces of the base layer are machined to control the ovality of the base layer.

[0012] Furthermore, the base layer is made of a metal plate by rolling and welding, and the length of the metal plate is smaller than the circumference of the circle after rolling, so as to form a welding position between the two ends of the metal plate after rolling.

[0013] Furthermore, the metal layer is bonded to the surface of the base layer by surfacing or spraying.

[0014] Furthermore, the material of the sliding layer is a polymer, and the sliding layer is combined on the surface of the metal layer by spraying.

[0015] Furthermore, the material of the base layer is low carbon steel, and the material of the metal layer is copper-based alloy, aluminum-based alloy or tin-based alloy.

[0016] Furthermore, the thickness of the base layer is not less than 6 mm, and the thickness of the sliding layer is between 0.01-0.03 mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A front view of the sliding bearing prepared by the manufacturing method of the present invention in use; Figure 2 A structural diagram of a sliding bearing prepared by the manufacturing method of the present invention; Figure 3 It is a process diagram of rolling and welding of the substrate layer in the manufacturing method of the present invention; Figure 4 A surface convexity diagram of a sliding bearing prepared by the manufacturing method of the present invention; Figure 5 This is a side view of the sliding bearing prepared by the manufacturing method of the present invention in use.

[0018] In the figure: 100, sliding bearing; 101, first oil hole; 1, base layer; 11, metal plate; 12, weld; 2, metal layer; 3, sliding layer; 4, planetary shaft; 41, second oil hole; 5, planetary gear; 6, oil chamber. DETAILED DESCRIPTION

[0019] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0020] In response to the technical problems existing in the prior art, the basic technical concept of the present invention is to first roll and weld the metal plate into a cylindrical base layer, or to directly cut the metal round tube to obtain the base layer, and then apply the working layer on the inner surface or outer surface of the base layer through an additive manufacturing process. The working layer does not need to be rolled again, which can avoid bruises or indentations on the surface of the working layer. At the same time, the working layer does not need to be welded again, which can avoid affecting the performance of the working layer.

[0021] Embodiment 1 of the method for manufacturing a sliding bearing in the present invention: like Figure 1 and Figure 2 As shown, the sliding bearing 100 includes a base layer 1, a metal layer 2 and a sliding layer 3. The metal layer 2 in this embodiment is arranged on the outer surface of the base layer 1, and the sliding layer 3 is arranged on the outer surface of the metal layer 2. When in use, the inner hole of the base layer 1 is interference-fitted with the planetary shaft 4, and both ends of the planetary shaft 4 are fixed on the planetary carrier of the gearbox gear train. A planetary gear 5 is arranged on the outside of the sliding bearing 100, and an oil chamber 6 is formed between the outer surface of the sliding layer 3 and the planetary gear 5.

[0022] The manufacturing method of the sliding bearing 100 comprises the following steps: like Figure 3 As shown, firstly, a flat metal plate 11 is rolled and welded to form a cylindrical base layer 1, and then Figure 2 and Figure 4 As shown, the metal layer 2 is first applied to the outer surface of the base layer 1 by an additive manufacturing process, and then the sliding layer 3 is applied to the surface of the metal layer 2 by an additive manufacturing process. The metal layer 2 and the sliding layer 3 are collectively referred to as working layers.

[0023] The base layer 1 needs to have sufficient rigidity to support the overall operation of the sliding bearing, and economical hard metal is preferred, for example, the material of the metal plate 11 is low carbon steel. For the convenience of welding, the length of the metal plate 11 is made smaller than the circumference of the circle after rolling, so as to form a weld position between the two ends of the metal plate 11 after rolling, that is, the metal plate 11 is first rolled into an unclosed cylindrical structure, and then the two end faces of the metal plate 11 are connected by welding technology to form a weld 12. When rolling, it can be formed by a press mold or rolled by a plate rolling machine.

[0024] After the metal plate 11 is welded, the deformation of the heat-affected zone in the welding area causes the ovality of the sliding bearing to increase. Therefore, the ovality of the base layer 1 must be controlled by mold shaping or by selecting a steel plate with a large margin for rolling and welding and then lathing. However, the base layer 1 must have sufficient thickness to ensure the rigidity of the entire sliding bearing. In this embodiment, since the base layer is made of a metal plate 11, the metal plate 11 has a wide range of options, and the size and thickness are easy to control. Therefore, a steel plate with a large margin is selected for rolling and welding, and then the inner and outer surfaces and end faces of the base layer are machined. Rust and cracks are not allowed on the surface of the base layer, and the ovality of the base layer is controlled. Specifically, the inner and outer diameter ovality cannot exceed 0.2 mm, and the thickness of the base layer after processing is not less than 6 mm to ensure the rigidity of the sliding bearing. During the processing, the weld position needs to be marked to accurately locate the direction of the weld 12 during the later installation.

[0025] After the base layer 1 is processed and formed, the metal layer 2 is bonded to the outer surface of the base layer 1 by surfacing or spraying. Specifically, the metal layer 2 can be bonded to the surface of the base layer 1 by surfacing methods such as laser cladding, cold melting, and spraying to ensure reliable bonding force; of course, it can also be bonded to the surface of the base layer 1 by spraying (including hot spraying and cold spraying), which is highly efficient and has a wide range of coating thicknesses. In particular, cold spraying does not change the properties of special sliding metal materials. The raw material form of the metal layer 2 can be metal powder or metal welding wire, and the raw material is copper-based alloy, aluminum-based alloy or tin-based alloy.

[0026] After the metal layer 2 is surfacing or sprayed, the surface of the metal layer 2 is modified by grinding, and the modification method includes multiple directional modification and logarithmic modification. Figure 4 As shown, the surface of the metal layer 2 is trimmed into a curved surface with a convex middle portion in the axial direction, that is, only the two axial sides of the metal layer 2 are ground so that the middle portion is convex, and the trimming depth h cannot exceed the thickness s of the metal layer 2. Specifically, the surface roughness of the metal layer 2 is between 1.6-3.2 μm, the thickness of the metal layer 2 is 1-3 mm, and the trimming amount is between 0.5-1 mm, for example, when the thickness is 1 mm, the trimming amount is 0.5 mm, or when the thickness is 3 mm, the trimming amount is 1 mm.

[0027] Finally, the sliding layer 3 is combined with the surface of the metal layer 2 by spraying. The spraying material is a polymer solution. The surface roughness after spraying does not exceed 0.8 μm. The coating thickness (i.e., the thickness of the sliding layer 3) is between 0.01 and 0.03 mm, specifically 0.01 mm, 0.02 mm, or 0.03 mm. The coating material includes polyetheretherketone, polyimide, polyamideimide, and polytetrafluoroethylene. At the same time, during the spraying process, the wall thickness of the sliding layer 3 is ensured to be uniform, so as to obtain a sliding layer with a convex surface, which can reduce stress concentration during the operation of the sliding bearing.

[0028] When the sliding bearing is in use, Figure 5 As shown, it is also necessary to process the first oil hole 101 on the sliding bearing 100 to communicate with the second oil hole 41 on the planetary shaft 4, so that the lubricating oil can enter the oil chamber 6 through the second oil hole 41 and the first oil hole 101. Since the sliding bearing 100 is interference-fitted on the planetary shaft 4, during use, the sliding bearing 100 remains stationary, and the planetary gear 5 rotates relative to the sliding bearing 100. During assembly, it is necessary to ensure that the weld 12 is in the non-load area of ​​the sliding bearing 100 and the planetary gear 5 to avoid stress on the weld 12. The outer opening of the first oil hole 101 faces the non-load area. During use, the planetary gear 5 and the sliding bearing 100 rotate relative to each other, and the lubricating oil will enter the load area below the planetary gear 5 and the sliding bearing 100 along the rotation direction.

[0029] Compared with the existing composite metal plate rolling scheme, the manufacturing method of the present invention does not require complicated multi-layer metal plate rolling, does not need to bear the risk of insufficient performance of each metal layer of the raw material, the risk of rolling damaging the performance of the special metal layer, and the problem of many welding restrictions. It directly selects metal plates to roll and weld to form a cylindrical base layer, and then applies a metal layer on the surface of the base layer through an additive manufacturing process, and finally applies a sliding layer on the surface of the metal layer through an additive manufacturing process. The metal plate has a wide range of options, the required size is easy to obtain, the raw material can be an economical metal material, and the welding technology can meet the required performance by using common welding technology. By selecting a metal plate with a processing allowance, the ellipticity of the base layer can be corrected by machining after welding is completed. Since the metal layer and the sliding layer have not been applied at this time, they will not have any impact on them and will not damage the formed working layer structure. The welding process will also not affect the working layer that has not yet been applied, ensuring the performance of the sliding bearing.

[0030] Embodiment 2 of the manufacturing method of the sliding bearing in the present invention: Different from Embodiment 1, the base layer in this embodiment is made by directly cutting metal round tubes, which has the advantages of simple process, stable structure, and only needs to cut the required length size, and because there is no weld, there is no restriction on the load zone, so it can be fixed in the inner hole of the planetary gear during assembly, and can be interference-fitted with the planetary gear or on the planetary shaft. The disadvantage is that there are fewer choices of metal tube materials and thickness size segments with different requirements.

[0031] In other embodiments of the method for manufacturing a sliding bearing: the thickness of the base layer may also be less than 6 mm, for example, 5.5 mm; the thickness of the sliding layer may also be greater than 0.03 mm, for example, 0.04 mm.

[0032] In other embodiments of the method for manufacturing a sliding bearing: the material of the base layer may also be alloy steel; the metal layer may also be other alloy materials, such as magnesium-based alloys, and of course may not be alloy materials, such as pure copper or pure aluminum.

[0033] In other embodiments of the method for manufacturing a sliding bearing: the material of the sliding layer may also be a material with good lubrication properties such as graphite or ceramics; the sliding layer may also be combined with the metal layer by sintering.

[0034] In other embodiments of the method for manufacturing a sliding bearing: the metal layer may also be bonded to the surface of the base layer by sintering.

[0035] In other embodiments of the manufacturing method of the sliding bearing: when the base layer is formed by rolling and welding the metal plate, the length of the metal plate can be equal to the circumference of the circle after rolling. At this time, the two end surfaces of the metal plate are directly connected. At this time, in order to facilitate welding, grooves need to be processed at both ends of the metal plate in advance.

[0036] In other embodiments of the method for manufacturing a sliding bearing: when the base layer is formed by rolling and welding a metal plate, by designing the dimensions in advance, the base layer after welding may no longer be machined, but may be shaped using a mold to control the ovality.

[0037] In other embodiments of the method for manufacturing a sliding bearing: the thickness of the metal layer may also be greater than 3 mm, for example, 3.5 mm, and the shaping amount may be greater than 1 mm, for example, 1.5 mm.

[0038] In other embodiments of the manufacturing method of the sliding bearing: after the metal layer is formed, the surface of the metal layer may no longer be modified. At this time, the outer peripheral surface of the metal layer is a cylindrical surface. If the wall thickness of the sliding layer finally obtained is uniform, then its outer peripheral surface is also a cylindrical surface. Of course, the wall thickness of the sliding layer can also be controlled to be uneven, for example, thick in the middle and thin on both sides. At this time, a sliding layer with a convex surface can also be formed.

[0039] In other embodiments of the method for manufacturing a sliding bearing: the sliding bearing may not include a sliding layer, and the surface of the metal layer is the working surface, that is, the working layer has only one metal layer.

[0040] In other embodiments of the method for manufacturing a sliding bearing: the sliding bearing may not include a metal layer, and only a sliding layer is provided on the surface of the base layer, that is, the working layer has only one sliding layer.

[0041] In other embodiments of the method for manufacturing a sliding bearing: according to the specific design of the sliding bearing, the working layer may also have three layers, for example, two metal layers and one sliding layer.

[0042] In other embodiments of the method for manufacturing a sliding bearing: if the working layer is applied to the inner surface of the base layer, the sliding bearing is used for interference fit with the planetary gear, and the inner hole of the sliding bearing is used for mutual rotational cooperation with the planetary shaft.

[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. The patent protection scope of the present invention shall be based on the claims. All equivalent structural changes made using the contents of the description and drawings of the present invention should also be included in the protection scope of the present invention.

Claims

1. A method for manufacturing a sliding bearing, characterized in that: The method comprises the following steps: firstly, a metal plate is rolled and welded to form a cylindrical base layer, or a metal round tube is directly cut to form the base layer, and then a working layer is applied to the inner surface or outer surface of the base layer by an additive manufacturing process.

2. The method for manufacturing a sliding bearing according to claim 1, characterized in that: The working layer includes a metal layer and a sliding layer. During manufacturing, the metal layer is first applied to the inner surface or outer surface of the base layer by an additive manufacturing process, and then the sliding layer is applied to the surface of the metal layer by an additive manufacturing process.

3. The method for manufacturing a sliding bearing according to claim 2, characterized in that: Before applying the sliding layer, the surface of the metal layer is firstly trimmed to form a curved surface with a convex middle portion in the axial direction. Then, when applying the sliding layer, the wall thickness of the sliding layer is ensured to be uniform to obtain a sliding layer with a convex surface.

4. The method for manufacturing a sliding bearing according to claim 3, characterized in that: The thickness of the metal layer is 1-3 mm, and the shaping amount is between 0.5-1 mm.

5. The method for manufacturing a sliding bearing according to any one of claims 1 to 4, characterized in that: The base layer is made of a metal plate through rolling, pressing and welding. After being made, the inner and outer surfaces and the end surface of the base layer are machined to control the ovality of the base layer.

6. The method for manufacturing a sliding bearing according to any one of claims 1 to 4, characterized in that: The base layer is made of a metal plate through rolling and welding, and the length of the metal plate is smaller than the circumference of a circle after rolling, so as to form a welding position between two ends of the rolled metal plate.

7. The method for manufacturing a sliding bearing according to any one of claims 2 to 4, characterized in that: The metal layer is bonded to the surface of the base layer by surfacing or spraying.

8. The method for manufacturing a sliding bearing according to any one of claims 2 to 4, characterized in that: The material of the sliding layer is polymer, and the sliding layer is combined on the surface of the metal layer by spraying.

9. The method for manufacturing a sliding bearing according to any one of claims 2 to 4, characterized in that: The material of the substrate layer is low carbon steel, and the material of the metal layer is copper-based alloy, aluminum-based alloy or tin-based alloy.

10. The method for manufacturing a sliding bearing according to any one of claims 2 to 4, characterized in that: The thickness of the base layer is not less than 6 mm, and the thickness of the sliding layer is between 0.01-0.03 mm.

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