Manufacturing method for dynamic pressure sliding bearing and dynamic pressure sliding bearing

Abstract

The invention relates to a manufacturing method for a dynamic pressure sliding bearing and the dynamic pressure sliding bearing. The dynamic pressure sliding bearing is of a cylindrical structure with an axial through center hole and is used for supporting a rotating part on the radial outer side face in a sliding mode, the manufacturing method comprises the steps that the dynamic pressure sliding bearing is formed through a casting technology, and the center hole, an oil channel and other structures are directly formed in the casting technology process. The manufacturing method and the dynamic pressure sliding bearing have improved processes.

Description

Technical Field

[0001] The present invention relates to the technical field of bearings. Specifically, the present invention relates to a manufacturing method for a hydrodynamic journal bearing and a hydrodynamic journal bearing. Background Art

[0002] With the development of the offshore wind power industry, large megawatt-class wind turbines have been increasingly applied. At the same time, the reduction of the unit power generation cost has imposed more stringent requirements on the cost and operating reliability of the gearbox. However, the steel shaft needs to be forged and heat-treated, and then the lubricating oil path is formed by machining. In addition, the hollow shaft also needs to be machined to form a central hole. The entire manufacturing process requires a large amount of time for installation, adjustment, and tool replacement. The axial deep hole also has higher requirements for the tool, increasing the tool cost, and the machining process itself also takes a lot of time, increasing the time cost. In addition, machining also increases the risk of manufacturing defects, such as burrs at the intersection of the axial hole and the radial hole. If not completely removed, it may enter the area of the functional surface, resulting in bearing failure. The bearing is a key component in the gearbox, and bearing failure will lead to the failure of the wind turbine gearbox, which requires a large amount of time and effort for maintenance, making the gearbox system lack obvious advantages in terms of cost-effectiveness. Summary of the Invention

[0003] Therefore, the technical problem to be solved by the present invention is to provide an improved manufacturing method for a hydrodynamic journal bearing and a hydrodynamic journal bearing.

[0004] The above technical problem is solved by a manufacturing method for a hydrodynamic journal bearing according to the present invention. The hydrodynamic journal bearing is a cylindrical structure with an axially penetrating central hole and is used to slidably support a rotating component on the radially outer surface. Wherein, the manufacturing method includes forming the hydrodynamic journal bearing by a casting process, and directly forming the central hole during the casting process. Since the central hole is directly formed in the casting process, the process of machining the central hole can be eliminated, thereby reducing the production cost and the risk of defects such as burrs on the surface of the central hole. At the same time, due to the use of the casting process, the shape and structure of the central hole are not restricted, and a more reasonable central hole structure (for example, a through hole, a stepped hole, an irregular hole, etc.) can be cast according to the specific application conditions and combined with simulation technology.

[0005] According to a preferred embodiment of the present invention, the hydrodynamic journal bearing may include one or more oil channels formed in the side wall, and the manufacturing method may include directly forming the one or more oil channels during the casting process. Directly forming the oil channels during the process of casting the entire hydrodynamic journal bearing can eliminate the process of machining the oil channels, thereby reducing the production cost.

[0006] According to another preferred embodiment of the present invention, each oil passage may include an axial section and a corresponding plurality of radial sections. Each radial section communicates with the corresponding axial section and extends radially to penetrate the radial outer surface of the hydrodynamic sliding bearing. The manufacturing method may include forming the axial section of each oil passage as a through hole axially penetrating the side wall during the casting process, and installing oil seals at both axial ends of the axial section of each oil passage after the casting process. Thereby, the casting difficulty of the axial section of the oil passage is reduced.

[0007] According to another preferred embodiment of the present invention, each oil passage may include an axial section and a corresponding plurality of radial sections. Each radial section communicates with the corresponding axial section and extends radially to penetrate the radial outer surface of the hydrodynamic sliding bearing. The manufacturing method may include forming the axial section of each oil passage as a hole closed at both axial ends during the casting process. Thereby, the manufacturing process is reduced.

[0008] According to another preferred embodiment of the present invention, the hydrodynamic sliding bearing may include one or more oil passages formed in the side wall. The manufacturing method may include presetting one or more oil pipes in the molding die during the casting process, such that the one or more oil pipes are embedded into the hydrodynamic sliding bearing through the casting process to provide one or more oil passages. Thereby, the casting difficulty of the oil passage is reduced and the manufacturing process is reduced.

[0009] According to another preferred embodiment of the present invention, the hydrodynamic sliding bearing may include an axial oil groove and a circumferential oil groove formed on the radial outer surface. The manufacturing method may include directly forming the axial oil groove and the circumferential oil groove during the casting process. Thereby, the machining process is further reduced.

[0010] According to another preferred embodiment of the present invention, the manufacturing method may include adding trace elements for increasing mechanical strength and / or toughness to the base material for forming the hydrodynamic sliding bearing during the casting process. Thereby, the mechanical properties of the casting product can be improved.

[0011] According to another preferred embodiment of the present invention, the manufacturing method may include performing heat treatment on the base material of the hydrodynamic sliding bearing after the casting process. Thereby, the mechanical properties of the hydrodynamic sliding bearing are further improved.

[0012] According to another preferred embodiment of the present invention, the manufacturing method may include performing surface treatment on the functional surface area of the hydrodynamic sliding bearing after the casting process. Thereby, the mechanical properties of the functional surface area are improved.

[0013] The above technical problem is also solved by a hydrodynamic sliding bearing according to the present invention. The hydrodynamic sliding bearing is used to slidably support a rotating component on the radial outer surface. Wherein, the hydrodynamic sliding bearing is manufactured by the above manufacturing method. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention will be further described below in conjunction with the drawings. The same reference numerals in the drawings represent elements with the same functions. Among them:

[0015] Figures 1a to 1c A longitudinal sectional view of a hydrodynamic sliding bearing manufactured by the manufacturing method according to an embodiment of the present invention; and

[0016] Figures 2a to 2b A perspective view of a hydrodynamic sliding bearing manufactured by the manufacturing method according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] The following will describe the manufacturing method for a hydrodynamic sliding bearing and the specific embodiments of the hydrodynamic sliding bearing according to the present invention in conjunction with the drawings. The following detailed description and drawings are used to exemplarily illustrate the principle of the present invention. The present invention is not limited to the described preferred embodiments, and the protection scope of the present invention is defined by the claims.

[0018] According to an embodiment of the present invention, a manufacturing method for a hydrodynamic sliding bearing is provided. The hydrodynamic sliding bearing is generally used to fixedly support a planet carrier and rotationally support planet gears in a planetary gear set of a wind turbine.

[0019] Figures 1a to 1c Longitudinal sectional views of different hydrodynamic sliding bearings 10 manufactured by the manufacturing method according to an embodiment of the present invention are respectively shown. As shown in the figure, the hydrodynamic sliding bearing 10 has a substantially cylindrical structure formed around a central axis, and has a central hole 11 that penetrates axially. The central hole 11 is arranged substantially coaxially with the side wall of the hydrodynamic sliding bearing 10. The planet gears 20 and the planet carrier 30 are respectively supported on the radially outer side surface of the hydrodynamic sliding bearing 10. Among them, the planet carrier 30 is fixedly connected to the hydrodynamic sliding bearing 10 (for example, by interference fit or welding, etc.). The planet gear 20 as a rotating component is axially located between two side portions of the planet carrier 30 and can rotate relative to the hydrodynamic sliding bearing 10 around the central axis by sliding along the radially outer side surface of the hydrodynamic sliding bearing 10. A thrust bearing 40 can be provided between the planet gear 20 and the adjacent planet carrier 30 to provide axial support.

[0020] In the manufacturing method according to the present invention, the hydrodynamic sliding bearing 10 is formed by a casting process, and the central hole 11 is directly formed during the casting process. The hydrodynamic sliding bearing 10 is generally cast into a hollow shaft in a molding die using cast iron material, so as to directly obtain the hydrodynamic sliding bearing 10 with the central hole 11. Different from the central hole obtained by machining a steel material in the prior art, the cast central hole 11 does not need to remove burrs, thus saving processes.

[0021] As Figure 1aAs shown, the cast central hole 11 can be formed as a straight cylindrical hole. Such a hole has a simple structure and is easy to manufacture. Alternatively, as Figure 1b and Figure 1c shown, the cast central hole 11 can also be formed as a stepped hole, that is, the central hole 11 has different hole diameters in different axial regions. In this case, in order to facilitate demolding, the hole diameter of the central hole 11 should gradually increase from the middle axial region to both sides or from one axial region at one end to the other axial region. Preferably, the region with a smaller hole diameter size can correspond to the load-bearing region of the hydrodynamic sliding bearing 10, that is, the axial middle region of the planetary gear 20, thereby increasing the side wall thickness and structural strength of the load-bearing region. On the premise of meeting the strength requirements, the larger the inner diameter of the central hole 11, the better, because the large-sized central hole 11 can not only save materials and reduce weight, but also improve the casting quality. In addition, based on the cast central hole 11, machining can be further performed to obtain the required shape, which can greatly reduce the machining allowance, shorten the machining time, improve production efficiency, and reduce manufacturing costs.

[0022] As Figures 1a to 1c shown, the hydrodynamic sliding bearing 10 further includes one or more oil channels formed in the side wall. In the manufacturing method according to some embodiments of the present invention, these oil channels are preferably also directly formed during the casting process.

[0023] Specifically, as shown in the figure, each oil channel can include an axial section 12 and a corresponding plurality of radial sections 13. The axial section 12 of each oil channel extends substantially axially in the side wall of the hydrodynamic sliding bearing 10, and each radial section 13 communicates with the corresponding axial section 12 and extends substantially radially from the axial section 12 until it penetrates the outer radial surface of the hydrodynamic sliding bearing 10. The plurality of radial sections 13 of each oil channel includes a radial section 13 for introducing lubricating oil, and the remaining radial sections 13 are used to supply lubricating oil to the outer radial surface. The radial section 13 for introducing lubricating oil is located at the outermost axial side of all the radial sections 13 and corresponds to the axial position of the planet carrier 30. The remaining radial sections 13 correspond to the axial positions of the planetary gears 20. The radial section 13 for introducing lubricating oil is aligned and communicated with the oil supply hole 31 in the planet carrier 30, so that lubricating oil can be introduced from the planet carrier 30 into the oil channel of the hydrodynamic sliding bearing 10. The introduced lubricating oil will flow through the axial section 12 to the remaining radial sections 13 and be supplied between the contact surfaces of the hydrodynamic sliding bearing 10 and the planetary gears 20 to provide hydrodynamic support and lubrication.

[0024] As Figure 1a and Figure 1bAs shown, in the manufacturing method according to some embodiments, the axial section 12 of each oil passage is first formed as a through hole axially penetrating the side wall during the casting process. After the casting process, oil seals 50 are respectively installed at the axial two ends of the axial section 12 formed as a through hole to seal the axial two ends of the axial section 12. Thus, the oil passage can only communicate with the outside through the radial section 13. Preferably, threads can be machined at both ends of the through hole for installing the oil seals 50. The axial section 12 formed as a through hole is convenient to realize during the casting process, especially for demolding. Moreover, such a through hole is also convenient for cleaning.

[0025] As Figure 1a and Figure 1b shown in the embodiment, as an alternative, as Figure 1c shown, in the manufacturing method according to some other embodiments, the axial section 12 of each oil passage is directly formed as a hole with both axial ends closed during the casting process. Such a casting process can be realized, for example, by the investment casting method. The advantage of such a closed hole is that subsequent machining and / or the process of installing oil seals can be omitted.

[0026] In the manufacturing method according to some other embodiments of the present invention, the oil passage in the hydrodynamic sliding bearing 10 can also be provided by a preset oil pipe. Specifically, in the manufacturing method, one or more oil pipes can be preset in the molding die during the casting process, and then these oil pipes are embedded into the hydrodynamic sliding bearing 10 through the casting process to provide the required oil passage. The oil passage formed by embedding the oil pipe here has basically the same structure as the oil passage in the Figures 1a to 1c shown embodiment, and will not be elaborated here.

[0027] Figure 2a and Figure 2b Figs. and respectively show different hydrodynamic sliding bearings 10 manufactured by the manufacturing method according to the present invention. As shown, the hydrodynamic sliding bearing 10 can also include an axial oil groove 14 and a circumferential oil groove 15 formed on the radial outer surface. The axial oil groove 14 extends substantially axially on the radial outer surface of the hydrodynamic sliding bearing 10, and its axial extension range is within the axial projection area of the planetary gear 20. The circumferential oil groove 15 extends substantially radially on the radial outer surface of the hydrodynamic sliding bearing 10 and communicates with the axial oil groove 14, and it is also located within the axial projection area of the planetary gear 20 and can be located at approximately the axial middle of the hydrodynamic sliding bearing 10. As Figure 2a shown, the circumferential oil groove 15 can only extend partially around the radial outer surface of the hydrodynamic sliding bearing 10 and only communicate with the circumferential side of the axial oil groove 14, or, as Figure 2bAs shown, the circumferential oil groove 15 can also form an annular groove around the hydrodynamic sliding bearing 10 and communicate with both circumferential sides of the axial oil groove 14. Preferably, in the manufacturing method according to the present invention, the axial oil groove 14 and the circumferential oil groove 15 can be directly formed during the casting process. This further reduces subsequent machining operations.

[0028] According to FEA (finite element) analysis, the mechanical properties of such a hydrodynamic sliding bearing 10 formed by the casting process can meet the requirements of various working conditions. In addition, the mechanical properties of this hydrodynamic sliding bearing 10 can be further improved by other processing techniques.

[0029] For example, according to some preferred embodiments, in this manufacturing method, trace elements for increasing mechanical strength and / or toughness can be added to the base material for forming the hydrodynamic sliding bearing 10 during the casting process, so that the base material reaches a higher spheroidization grade. According to some preferred embodiments, after the casting process, the base material of the hydrodynamic sliding bearing 10 can also be heat-treated, such as isothermal quenching, so that the graphite balls are more evenly distributed on the surface of the base material to prepare for subsequent processes. In addition, according to some other preferred embodiments, after the casting process, the functional surface area of the hydrodynamic sliding bearing 10 (i.e., the area of the radially outer surface for slidingly supporting the planetary gear 20) can also be surface-treated, and such surface treatment can be laser cladding, special heat treatment (such as soft nitriding), applying a special coating (such as DLC), etc.

[0030] According to another embodiment of the present invention, a hydrodynamic sliding bearing 10 is also provided. This hydrodynamic sliding bearing 10 is manufactured by the manufacturing method according to any of the above embodiments, and thus correspondingly has the various features and advantages in the above embodiments.

[0031] The manufacturing method according to the present invention uses a cast iron material to cast the hydrodynamic sliding bearing, so that material and processing costs can be saved, and there is an obvious cost advantage. In the casting process, structures such as the central hole and oil passage of the hydrodynamic sliding bearing can be formed simultaneously, which can not only reduce weight and save materials, but also reduce machining operations, thereby simplifying the manufacturing process and reducing process defects caused by machining.

[0032] Although possible embodiments have been described by way of example in the foregoing description, it should be understood that there are numerous variations of the embodiments through all known and additionally those that are readily conceivable by a person skilled in the art in combination with technical features and implementation manners. Furthermore, it should also be understood that the exemplary implementation manners are merely an example, and such embodiments in no way limit the protection scope, application, and construction of the present invention. Through the foregoing description, more is to provide a technical guidance for a person skilled in the art to transform at least one exemplary implementation manner, wherein various changes can be made as long as the protection scope of the claims is not departed from, especially changes regarding the functions and structures of the components.

[0033] List of Reference Numerals

[0034] 10 Hydrodynamic sliding bearing

[0035] 11 Central hole

[0036] 12 Axial section

[0037] 13 Radial section

[0038] 14 Axial oil groove

[0039] 15 Circumferential oil groove

[0040] 20 Planet gear

[0041] 30 Planet carrier

[0042] 31 Oil supply hole

[0043] 40 Thrust bearing

[0044] 50 Oil seal

Claims

1. A manufacturing method for a hydrodynamic sliding bearing (10), the hydrodynamic sliding bearing (10) being a cylindrical structure with an axially penetrating central hole (11) and being used for slidingly supporting a rotating component on a radially outer side surface, characterized in that, the manufacturing method includes forming the hydrodynamic sliding bearing (10) by a casting process, and directly forming the central hole (11) during the casting process.

2. The manufacturing method according to claim 1, characterized in that, the hydrodynamic sliding bearing (10) includes one or more oil channels formed in a side wall, and the manufacturing method includes directly forming the one or more oil channels during the casting process.

3. The manufacturing method according to claim 2, characterized in that, each oil channel includes an axial section (12) and a corresponding plurality of radial sections (13), each radial section (13) communicating with the corresponding axial section (12) and extending radially to penetrate the radially outer side surface of the hydrodynamic sliding bearing (10), and the manufacturing method includes forming the axial section (12) of each oil channel as a through hole axially penetrating the side wall during the casting process, and installing oil seals (50) at both axial ends of the axial section (12) of each oil channel after the casting process.

4. The manufacturing method according to claim 2, characterized in that, each oil channel includes an axial section (12) and a corresponding plurality of radial sections (13), each radial section (13) communicating with the corresponding axial section (12) and extending radially to penetrate the radially outer side surface of the hydrodynamic sliding bearing (10), and the manufacturing method includes forming the axial section (12) of each oil channel as a hole with both axial ends closed during the casting process.

5. The manufacturing method according to claim 1, characterized in that, the hydrodynamic sliding bearing (10) includes one or more oil channels formed in a side wall, and the manufacturing method includes presetting one or more oil pipes in a molding die during the casting process, so that the one or more oil pipes are embedded in the hydrodynamic sliding bearing (10) through the casting process to provide the one or more oil channels.

6. The manufacturing method according to claim 1, characterized in that, the hydrodynamic sliding bearing (10) includes an axial oil groove (14) and a circumferential oil groove (15) formed on a radially outer side surface, and the manufacturing method includes directly forming the axial oil groove (14) and the circumferential oil groove (15) during the casting process.

7. The manufacturing method according to claim 1, characterized in that, the manufacturing method includes adding trace elements for increasing mechanical strength and / or toughness to a base material for forming the hydrodynamic sliding bearing (10) during the casting process.

8. The manufacturing method according to claim 1, characterized in that, the manufacturing method includes performing heat treatment (isothermal quenching) on the base material of the hydrodynamic sliding bearing (10) after the casting process.

9. The manufacturing method according to any one of claims 1 to 8, characterized in that, The manufacturing method includes surface treatment (laser cladding, soft nitriding, coating application) of the functional surface area of the hydrodynamic sliding bearing (10) after the casting process.

10. A hydrodynamic sliding bearing (10) for slidingly supporting a rotating component on a radially outer side surface, characterized in that the hydrodynamic sliding bearing (10) is manufactured by the manufacturing method according to any one of claims 1 to 9.

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