Variable damping tilting pad bearing

Abstract

The invention discloses a variable-damping tilting pad bearing, and relates to the technical field of sliding bearings. Comprising an upper half bearing shell, a lower half bearing shell, spherical supports, oil injection devices, tilting pads and bearing end covers, the upper half bearing shell and the lower half bearing shell form an annular bearing shell, the tilting pads are arranged on the inner side of the annular bearing shell and distributed at equal intervals in the circumferential direction, and the spherical supports are installed between the pad backs of the tilting pads and the annular bearing shell. The oil spraying devices are arranged between the adjacent tilting pads, the bearing end covers are installed on the two axial sides of the annular bearing shell, and through drainage holes are formed in the spherical supports and the tilting pads. Lubricating oil sprayed into the tile surfaces of the tilting tiles from an oil spraying device forms a high-pressure power oil film on the tile surfaces, part of the high-pressure lubricating oil enters the space between the spherical support and the annular bearing shell through the through drainage holes, high-pressure radial jacking force is formed, the spherical support is jacked up, and a static-pressure oil film is formed between the spherical support and the annular bearing shell. And the supporting damping of the tilting pad is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of sliding bearings, and particularly relates to a variable-damping tilting pad bearing. Background Art

[0002] The tilting pad bearing is a high-performance sliding bearing. Due to its excellent stability, it is widely used in high-speed, heavy-load, and high-precision rotating machinery. For example, the tilting pad bearing can be used for the support of the rotor of a heavy-duty gas turbine. However, the rotor supported by the tilting pad bearing often has a problem of excessive shaft vibration, which seriously threatens the safe operation of the equipment. The bearing provides the stiffness and damping boundaries for the operation of the rotor and is one of the main factors affecting the rotor vibration.

[0003] In the prior art, the back of the tilting pad of the tilting pad bearing is in rigid contact with the bearing housing. The support damping of the tilting pad mainly comes from the dynamic oil film on the pad surface, and the long-term operation of the bearing is also likely to cause wear at the contact points of the back of the pad. For the current rotor vibration problem, the prior art solutions mostly start from the bearing and suppress the vibration by means of adjusting the bearing clearance, reducing the width of the bearing bush, increasing the bearing load, etc. In essence, it is also to adjust the support stiffness and damping of the bearing. The main problems existing in the prior art solutions are as follows:

[0004] (1) The back of the tilting pad of the tilting pad bearing is in rigid contact with the bearing housing, and almost no damping can be provided at the back of the pad support, which cannot well suppress the rotor vibration;

[0005] (2) The back of the tilting pad of the tilting pad bearing is in rigid contact with the bearing housing, and the long-term operation of the bearing is also likely to cause wear at the contact points of the back of the pad, resulting in an increase in the bearing clearance and affecting the running stability of the rotor;

[0006] (3) If a rotor vibration problem occurs on site and it is desired to suppress the vibration starting from the bearing, it is necessary to stop the machine, disassemble the bearing housing, and disassemble the bearing before implementation. The workload is large, the working cycle is long, the investment in manpower and material resources is large, and the shutdown of the equipment will also cause relatively large economic losses. Especially for some gas turbines or scaled-down test pieces of gas turbines, the bearing housing cannot be separately opened without removing the upper cylinder. In this case, it is necessary to first lift the upper half of the cylinder to open the bearing housing, which further increases the difficulty of on-site construction;

[0007] (4) If on-site adjustment of the bearing is required, it often depends on the experience of the engineer, and sometimes multiple adjustments are required to achieve the desired effect;

[0008] (5) The means of adjusting the bearing parameters on site are after all limited. Sometimes, although the bearing parameters have been adjusted multiple times, the effect of suppressing vibration cannot be well achieved.

[0009] The existing patent CN112377522A discloses a self-aligning support bearing, which includes a tile body, a tile pillow, an oil inlet structure, a drainage hole, an oil pocket and an oil distribution structure. A spherical fit is formed between the tile body and the tile pillow. The oil inlet structure is used to introduce lubricating oil into the annular gap formed between the inner surface of the tile body and the rotor. The drainage hole is located in the lower half of the tile body and is distributed along the axial direction of the tile body. The drainage hole communicates with the annular gap. The oil pocket is arranged in the lower half of the tile pillow and is distributed along the axial direction of the tile pillow, and the oil pocket is located on the mating spherical surface between the tile pillow and the tile body. The oil distribution structure is used to connect the drainage hole and the oil pocket, so that the lubricating oil in the annular gap enters the oil pocket through the drainage hole.

[0010] The existing patent DE102018202529A1 discloses a radially tilting segment bearing for supporting a shaft, which includes a plurality of tilting segments distributed on the circumference of the radially tilting segment bearing and spaced apart from each other. An oil pocket is formed between the respective tilting segments, and the oil pocket can be acted on by the oil mass flow through the oil inlet. Each oil chamber has its own individually controllable oil supply, and through this oil source, the amount of oil supplied to each oil chamber can be set.

[0011] In summary, the above existing patents have not solved the problem of excessive shaft vibration of the rotor supported by the tilting pad bearing in the prior art. Summary of the Invention

[0012] Based on the above technical problems, the present invention proposes a variable-damping tilting pad bearing to solve the problem of excessive shaft vibration of the rotor supported by the tilting pad bearing in the prior art.

[0013] To achieve the above object, the present invention proposes a variable-damping tilting pad bearing. The specific technical solution is as follows:

[0014] A variable-damping tilting pad bearing includes an upper half of a bearing housing and a lower half of a bearing housing that form an annular bearing housing, tilting pad blocks arranged inside the annular bearing housing and equally spaced circumferentially, a spherical support installed on the back of the tilting pad blocks and forming a spherical fit with the inner side of the annular bearing housing, an oil injection device arranged between adjacent tilting pad blocks, and bearing end caps installed on both axial sides of the annular bearing housing. The oil injection device is used to provide lubricating oil, the bearing end caps are used to limit the tilting pad blocks, and a radially penetrating drainage hole is provided in the spherical support and the tilting pad blocks. The drainage hole is used to drain the high-pressure lubricating oil on the surface of the tilting pad blocks to between the spherical support and the annular bearing housing.

[0015] Further, a first drainage hole is radially provided at the center of the tilting pad block, and a second drainage hole is radially provided at the center of the spherical support. The apertures of the first drainage hole and the second drainage hole are the same and communicate with each other.

[0016] Further, the apertures of the first drainage hole and the second drainage hole are 4-6 mm.

[0017] Further, a first oil pocket is formed at the center of the bearing surface of the tilting pad, and the first drainage hole is formed at the center of the first oil pocket.

[0018] Further, the first oil pocket is oval, the depth of the first oil pocket is 0.2-0.3 mm, and the area of the first oil pocket is 1.0%-2.0% of the projected area of the bearing.

[0019] Further, a cylindrical hole is formed on the back of the tilting pad, and the spherical support is installed in the cylindrical hole.

[0020] Further, the spherical support includes a cylindrical end and a hemispherical end. The cylindrical end is installed in the cylindrical hole on the back of the tilting pad, and the hemispherical end is engaged with the spherical support mating hole on the inner side of the annular bearing housing.

[0021] Further, the distance between the bottom surface of the hemispherical end of each spherical support and the bearing surface of the corresponding tilting pad is the same.

[0022] Further, the bottom of the hemispherical end of the spherical support is a flat surface, and the gap between the spherical support and the annular bearing housing is a second oil pocket.

[0023] Further, it further includes a pad limit pin. First limit pin holes are formed on both axial sides of the tilting pad, second limit pin holes are formed on the inner side of the bearing end cover. One end of the pad limit pin is installed in the first limit pin hole, and the other end is installed in the second limit pin hole. The unilateral gap between the pad limit pin and the second limit pin hole is 1-1.5 mm.

[0024] Further, the inner side of the annular bearing housing is an annular boss. An oil injection device mounting table is arranged axially on the annular boss. The oil injection device mounting table is used for installing an oil injection device, and a spherical support mating hole is also arranged on the annular boss.

[0025] Further, both ends of the oil injection device mounting table are threaded mounting holes, and the middle is an oil inlet hole.

[0026] Further, a plurality of threaded mounting holes are formed circumferentially on both side surfaces of the annular boss, and the bearing end cover is fixedly installed on both sides of the annular boss through the threaded mounting holes.

[0027] Based on the above technical solutions, the present invention has at least the following beneficial effects:

[0028] 1. A variable-damping tilting pad bearing proposed by the present invention, both the tilting pad and the spherical support are processed with drainage holes, and the two drainage holes are communicated. The high-pressure lubricating oil on the surface of the tilting pad can enter the space between the spherical support and the bearing housing through the drainage holes to form a high-pressure jacking force to jack up the spherical support.

[0029] 2. A variable-damping tilting pad bearing proposed by the present invention forms a high-pressure oil film between the spherical support and the spherical mating hole of the bearing housing, which improves the damping of the tilting pad support, enhances the non-linear characteristics of the bearing, increases the stability margin of the bearing operation, and can effectively suppress rotor vibration.

[0030] 3. A variable-damping tilting pad bearing proposed by the present invention forms a high-pressure oil film between the spherical support and the spherical mating hole of the bearing housing, which can effectively avoid the wear of the fulcrum caused by the sliding friction between the spherical pairs.

[0031] 4. A variable-damping tilting pad bearing proposed by the present invention can form damping at the tilting pad support to resist vibration, avoiding the need to stop the machine for rectifying the bearing due to poor bearing stability, saving manpower and material resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0033] Figure 1 is a schematic structural diagram of a variable-damping tilting pad bearing proposed by the present invention;

[0034] Figure 2 is a cross-sectional schematic diagram of a variable-damping tilting pad bearing proposed by the present invention;

[0035] Figure 3 is a schematic structural diagram of the upper half of the bearing housing of a variable-damping tilting pad bearing proposed by the present invention;

[0036] Figure 4 is a schematic structural diagram of the lower half of the bearing housing of a variable-damping tilting pad bearing proposed by the present invention;

[0037] Figure 5 is a schematic structural diagram of the tilting pad of a variable-damping tilting pad bearing proposed by the present invention;

[0038] Figure 6 is a schematic structural diagram of the spherical support of a variable-damping tilting pad bearing proposed by the present invention.

[0039] Reference Numerals: 1 - upper half of bearing housing, 2 - spherical support, 3 - oil injection device, 4 - tilting pad, 5 - lower half of bearing housing, 6 - bearing end cover, 7 - pad position-limiting pin, 8 - bolt, 9 - oil injection device mounting table, 10 - oil inlet hole, 11 - spherical support mating hole, 12 - first oil pocket, 13 - first drainage hole, 14 - first position-limiting pin hole, 15 - second drainage hole, 16 - second oil pocket, 17 - second position-limiting pin hole. Detailed Embodiment

[0040] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other. The present invention will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0041] The following further describes the present invention in detail with specific embodiments, and these embodiments should not be construed as limiting the scope claimed by the present invention.

[0042] To solve the problem of excessive shaft vibration of the rotor supported by a tilting pad bearing in the prior art, the present invention proposes a variable-damping tilting pad bearing.

[0043] To achieve the above object, the present invention proposes a variable-damping tilting pad bearing. Refer to Figures 1 - 6 As shown, a specific example of a variable-damping tilting pad bearing is given.

[0044] Refer to Figure 1 As shown, the tilting pad bearing mainly includes the upper half 1 of the bearing housing, the lower half 5 of the bearing housing, the spherical support 2, the oil injection device 3 and the tilting pads 4. The upper half 1 of the bearing housing and the lower half 5 of the bearing housing form an annular bearing housing. The tilting pads 4 are circumferentially and equally spaced inside the annular bearing housing. The spherical support 2 is installed between the back of the tilting pads 4 and the inner side of the annular bearing housing. The oil injection device 3 is arranged between two adjacent tilting pads 4 and is fixed on the upper half 1 of the bearing housing or the lower half 5 of the bearing housing. The spherical support 2 and the tilting pads 4 are provided with through drainage holes. The high-pressure lubricating oil sprayed into the pad surface of the tilting pads 4 from the oil injection device 3 can enter between the spherical support 2 and the annular bearing housing through the through drainage holes to form a high-pressure radial jacking force. Under the action of the high-pressure jacking force, the spherical support 2 is jacked up, and a very thin static pressure oil film is formed between the spherical support 2 and the annular bearing housing. This static pressure oil film can increase the support damping of the tilting pads 4.

[0045] As a specific embodiment of the upper half 1 of the bearing housing and the lower half 5 of the bearing housing, refer to Figure 3 and Figure 4As shown, the upper half 1 of the bearing housing and the lower half 5 of the bearing housing are both semi-circular ring components. The mid-plane of the semi-circular ring component is provided with bolt holes. Through the bolt holes, the upper half 1 of the bearing housing and the lower half 5 of the bearing housing form a complete ring-shaped bearing housing for supporting and fixing the bearing. The inner side of the ring-shaped bearing housing is a ring-shaped boss. There are evenly spaced injection device mounting platforms 9 on the ring-shaped boss. The injection device mounting platform 9 is used to mount the injection device 3. The injection device mounting platform 9 is arranged along the axial direction of the ring-shaped bearing housing, and threaded mounting holes are opened at both ends and an oil inlet hole 10 is opened in the middle. There are also spherical support mating holes 11 on the ring-shaped boss between adjacent injection device mounting platforms 9. A plurality of threaded mounting holes are evenly spaced along the circumferential direction on the side surface of the ring-shaped boss.

[0046] Referring to Figure 2 As shown, the injection device 3 can be fixedly installed on the injection device mounting platform 9 through bolts 8. The tilting pad bearing further includes a bearing end cover 6. The bearing end cover 6 is installed on both sides of the ring-shaped boss through the threaded mounting holes on the side surface of the ring-shaped boss. A second limit pin hole 17 is opened circumferentially on one side of the bearing end cover 6 close to the ring-shaped boss for installing the pad limit pin 7.

[0047] As a specific embodiment of the tilting pad 4, referring to Figure 5 As shown, an elliptical first oil pocket 12 is opened on the pad surface of the tilting pad 4. A first drainage hole 13 is opened at the center of the first oil pocket 12. Limit pin holes 14 are opened at both axial ends of the tilting pad 4. The limit pin holes 14 are threaded mounting holes for installing the pad limit pin 7. Referring to Figure 1 As shown, a cylindrical hole is machined on the pad back of the tilting pad 4 for installing the spherical support 2. Referring to Figure 2 As described above, one end of the pad limit pin 7 is a threaded end and is fixedly installed in the limit pin hole 14 of the tilting pad 4. The other end of the pad limit pin 7 is installed in the second limit pin hole 17 of the bearing end cover 6. The unilateral clearance between the pad limit pin 7 and the second limit pin hole 17 is 1 - 1.5 mm, and the pad limit pin 7 can limit the circumferential displacement of the tilting pad 4.

[0048] Optionally, the depth of the first oil pocket 12 is 0.2 - 0.3 mm, and the area of the first oil pocket 12 is 1.0% - 2.0% of the bearing projection area.

[0049] Optionally, the diameter of the first drainage hole 13 is 4 - 6 mm.

[0050] As a specific embodiment of the spherical support 2, referring to Figure 1 and Figure 2As shown, the spherical support 2 consists of a cylindrical end and a hemispherical end. The cylindrical end is installed in the cylindrical hole on the back of the tilting pad 4, with an interference fit between the two. Four points are evenly riveted circumferentially for fixation. During installation, the thickness from the surface of all tilting pads 4 to the bottom of the hemispherical end of the corresponding spherical support 2 is controlled to be the same. The hemispherical end of the spherical support 2 mates with the spherical support mating hole 11 on the upper half 1 of the bearing housing or the lower half 5 of the bearing housing to form a spherical pair. The tilting pad 4 can swing freely in all directions around this spherical pair to form an optimal lubricating oil wedge according to the working conditions.

[0051] Refer to Figure 6 As shown, the bottom of the hemispherical end of the spherical support 2 is machined into a plane, and a second drainage hole 15 is machined at the center of the spherical support 2. Refer to Figure 2 As shown, the gap between the spherical support 2 and the annular bearing housing is the second oil pocket 16. The aperture of the second drainage hole 15 in the spherical support 2 is the same as that of the first drainage hole 13 in the tilting pad 4, and the two drainage holes are connected.

[0052] In the variable-damping tilting pad bearing proposed above, the oil injection device 3 injects high-pressure lubricating oil onto the surface of the tilting pad 4. The high-pressure lubricating oil enters the first oil pocket 12 on the surface of the tilting pad 4, passes through the first drainage hole 13 and the second drainage hole 15 to enter the second oil pocket 16. The high-pressure lubricating oil entering the second oil pocket 16 acts on the bottom surface of the hemispherical end of the spherical support 2 to form a radial jacking force. The higher the rotational speed of the tilting pad bearing, the greater the high-pressure jacking force formed. Under the action of the high-pressure jacking force, the spherical support 2 is jacked up, and a very thin static pressure oil film is formed between the spherical support 2 and the spherical support mating hole of the annular bearing housing. This static pressure oil film can increase the support damping of the tilting pad 4, enhance the non-linear characteristics of the tilting pad bearing, improve the stability margin of the tilting pad bearing during operation, and effectively suppress rotor vibration. If it is necessary to further increase the high-pressure jacking force, the area of the bottom surface of one end of the hemispherical surface of the spherical support 2 can be appropriately increased.

[0053] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

[0054] It should be noted that in this document, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variation thereof are intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0055] It should be noted that in the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

Claims

1. A variable damping tilting pad bearing, characterized in that: The invention comprises an upper half (1) of a bearing shell and a lower half (5) of a bearing shell constituting an annular bearing shell, tilting pads (4) arranged on the inner side of the annular bearing shell and distributed at equal intervals along the circumferential direction, a spherical support (2) installed on the back of the tilting pad (4) and forming a spherical fit with the inner side of the annular bearing shell, an oil spray device (3) arranged between adjacent tilting pads (4), and a bearing end cover (6) installed on both axial sides of the annular bearing shell, wherein the oil spray device (3) is used to provide lubricating oil, the bearing end cover (6) is used to limit the position of the tilting pad (4), and radially penetrating drainage holes are opened in the spherical support (2) and the tilting pad (4), and the drainage holes are used to drain the high-pressure lubricating oil on the pad surface of the tilting pad (4) to between the spherical support (2) and the annular bearing shell.

2. The variable damping tilting pad bearing according to claim 1, characterized in that: A first drainage hole (13) is radially opened at the center of the tilting pad (4), and a second drainage hole (15) is radially opened at the center of the spherical support (2); the first drainage hole (13) and the second drainage hole (15) have the same aperture and are connected.

3. The variable damping tilting pad bearing according to claim 2, characterized in that: The diameters of the first drainage hole (13) and the second drainage hole (15) are 4-6 mm.

4. The variable damping tilting pad bearing according to claim 2, characterized in that: A first oil bag (12) is provided at the center of the pad surface of the tilting pad (4), and the first drainage hole (13) is provided at the center of the first oil bag (12).

5. The variable damping tilting pad bearing according to claim 4, characterized in that: The first oil bag (12) is elliptical in shape, the depth of the first oil bag (12) is 0.2-0.3 mm, and the area of ​​the first oil bag (12) is 1.0%-2.0% of the projected area of ​​the bearing.

6. The variable damping tilting pad bearing according to claim 4, characterized in that: The back of the tilting pad (4) is provided with a cylindrical hole, and the cylindrical hole is used for installing the spherical support (2).

7. The variable damping tilting pad bearing according to claim 6, characterized in that: The spherical support (2) comprises a cylindrical end and a semi-spherical end, the cylindrical end is installed in the cylindrical hole of the back of the tilting pad (4), and the semi-spherical end cooperates with the spherical support matching hole on the inner side of the annular bearing housing.

8. The variable damping tilting pad bearing according to claim 7, characterized in that: The distance between the bottom surface of the hemispherical end of each spherical support (2) and the pad surface of the corresponding tilting pad (4) is the same.

9. The variable damping tilting pad bearing according to claim 7, characterized in that: The bottom of the semi-spherical end of the spherical support (2) is a plane, and the gap between the spherical support (2) and the annular bearing housing is a second oil bag (16).

10. The variable damping tilting pad bearing according to claim 1, characterized in that: It also includes a tile limit pin (7), wherein a first limit pin hole (14) is provided on both axial sides of the tilting tile (4), and a second limit pin hole (17) is provided on the inner side of the bearing end cover, one end of the tile limit pin (7) is installed in the first limit pin hole (14), and the other end is installed in the second limit pin hole (17), and the single-side clearance between the tile limit pin (7) and the second limit pin hole (17) is 1-1.5 mm.

11. The variable damping tilting pad bearing according to claim 10, characterized in that: The inner side of the annular bearing housing is an annular boss, on which an oil spray device mounting platform (9) is provided. The oil spray device mounting platform (9) is used to mount an oil spray device (3), and a spherical support fitting hole (11) is also provided on the annular boss.

12. The variable damping tilting pad bearing according to claim 11, characterized in that: The two ends of the oil spray device mounting platform (9) are threaded mounting holes, and the middle is an oil inlet hole (10).

13. The variable damping tilting pad bearing according to claim 11, characterized in that: A plurality of threaded mounting holes are provided on the two side surfaces of the annular boss along the circumferential direction, and the bearing end cover (6) is fixedly mounted on the two sides of the annular boss through the threaded mounting holes.

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