A tilting-pad radial load bias bearing for an ultra-supercritical steam turbine unit

Abstract

A kind of tilting-pad radial partial load bearing for ultra-supercritical steam turbine unit.It relates to the field of steam turbine unit sliding bearing.When existing actual load is inconsistent with design load, it leads to uneven temperature of left and right pads, insufficient oil film thickness, and easily causes wear and vibration problems.The tilting-pad radial sliding bearing includes bearing shell, upper supporting pad, lower supporting pad, stop pin, gasket set, cylindrical gasket, adjusting gasket, supporting pin, spring, oil seal ring, check valve, oil baffle, oil injection port.The supporting part adopts four-pad tilting-pad structure, and the relative position of fulcrum of pad is LC / L=0.6 (LC is the arc length of fulcrum position of pad, and L is the arc length of pad).Eccentric support is realized by the angle of deflection pad and bearing center line, and the deflection angle A is 7.5°.The utility model is applied to tilting-pad radial partial load bearing for ultra-supercritical steam turbine unit.

Description

Technical Field

[0001] This utility model relates to the field of sliding bearings for steam turbine units, specifically to a tilting pad radial off-center bearing for ultra-supercritical steam turbine units. Background Technology

[0002] Over the past 20 years, with the development of thermal power turbine technology and changes in the economic environment, my country's thermal power turbines have gradually evolved into high-parameter units of the ultra-supercritical 1000MW class, with increasingly stringent requirements for unit operational stability. To address the shaft system stability issues in the ultra-high-pressure sections of some 1000MW units and improve the bearing's anti-interference capability, a radial sliding bearing with eccentric support and tilting pads needs to be designed.

[0003] Most 1000MW-class thermal power turbine units currently use center-supported tilting pad sliding bearings for their No. 1 bearings. During actual operation, the bearings are affected by lateral loads, resulting in discrepancies between the bearing load and the design load. This can easily lead to large temperature differences between the left and right pads, abnormal bearing wear, and other problems that compromise the safe and stable operation of the unit. Utility Model Content

[0004] To address the problem that uneven temperature and insufficient oil film thickness on the left and right bearings, which easily lead to wear and vibration, when the lateral load is inconsistent with the design load, this invention provides a tilting bearing radial off-center load bearing for ultra-supercritical steam turbine units.

[0005] The technical solution of this utility model is:

[0006] A tilting pad radial off-center bearing for ultra-supercritical steam turbine units comprises a bearing housing, and the tilting pad radial off-center bearing for ultra-supercritical steam turbine units further comprises a set of support pads, support pins and adjusting pads;

[0007] A set of support pads forms a support part. The set of support pads is connected to the bearing housing through support pins and adjusting pads to achieve point support. The set of support pads is arranged end to end on the inner side of the bearing housing.

[0008] A set of support pads consists of four pads, which are composed of two upper support pads and two lower support pads. The support points of the two upper support pads and the two lower support pads are located at 45° from the midpoint of the upper and lower halves of the bearing housing, respectively.

[0009] Furthermore, an oil supply port is provided between the upper support pad and the lower support pad, and the included angle between the oil supply port and the center line of the bearing housing is A, and the included angle A is 7.5°.

[0010] Furthermore, the relative positions of the fulcrums of the two upper supporting tiles and the two lower supporting tiles are Lc and L, respectively, where Lc / L = 0.6;

[0011] Where Lc is the arc length of the fulcrum position of the tile, and L is the arc length of the tile.

[0012] Furthermore, a spring is provided between the upper support pad and the bearing housing, and the upper support pad is connected to the bearing housing through the spring, so that the upper support pad is in contact with the rotor.

[0013] Furthermore, the oil wedge of the upper support pad is arc-shaped, and the oil wedge of the upper support pad is not concentric with the bearing centerline of the bearing housing.

[0014] Furthermore, the tilting pad radial eccentric bearing for ultra-supercritical steam turbine units also includes cylindrical pads and a set of shims;

[0015] The tilting pad radial off-center load bearing of the ultra-supercritical steam turbine unit is supported on the bearing housing bearing seat by cylindrical pads and shim sets;

[0016] The shim set is set in the outer groove of the bearing housing, and the cylindrical pad presses the shim set into the groove of the bearing housing. The shim set adjusts the vertical and horizontal position of the tilting pad radial off-center bearing for ultra-supercritical steam turbine units.

[0017] Furthermore, the diameter of the cylindrical pad is larger than the diameter of the bearing housing, and the upper surface of the cylindrical pad has a groove. The groove on the cylindrical pad restricts the axial degree of freedom of the tilting pad radially offset bearing for ultra-supercritical steam turbine units.

[0018] Furthermore, the tilting pad radial eccentric bearing for ultra-supercritical steam turbine units also includes a retaining pin;

[0019] The stop pin is connected to the bearing housing. The stop pin is lower than the horizontal split surface of the bearing housing. The side of the stop pin away from the bearing housing extends into a groove in the bearing housing bearing seat, thus constraining the axial rotational freedom of the bearing.

[0020] Furthermore, the tilting pad radial off-center bearing for ultra-supercritical steam turbine units also includes a first oil seal ring, a second oil seal ring, and a check valve;

[0021] The first and second oil seal rings are fastened to both sides of the bearing housing by screws, and the check valve is integrated in the top shaft connector and located at the inlet of the top shaft oil line.

[0022] Furthermore, the first oil seal ring, the second oil seal ring, and the check valve constitute the auxiliary part of the tilting pad radial off-center bearing for ultra-supercritical steam turbine units.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] Compared to traditional bearing supports, which use symmetrical support with Lc / L=0.5 (where Lc is the arc length of the bearing pad's fulcrum and L is the arc length of the bearing pad with the fulcrum at the center and symmetrical force distribution), this new bearing pad uses eccentric support with Lc / L=0.6, offset towards the tail by 60% of the arc length. This 0.6 fulcrum position shifts the peak oil film pressure towards the tail of the bearing pad, increasing load-bearing capacity by 15%-20%. It also enhances resistance to eccentric loads. Furthermore, this new design increases the oil film thickness by 20%-30%, with the upper bearing pad's arc-shaped oil wedge eccentric to the centerline, optimizing the lubricant flow path. Compared to traditional bearing lateral load adaptability, which requires additional adjustment, this design automatically adapts to rotor eccentric loads.

[0025] This invention features a spring between the bearing housing and the upper support pad. The spring is fitted with the upper support pad and applies a preload to ensure rotor contact and avoid dry friction. The spring provides auxiliary contact to ensure that the rotor contacts the pad at low speeds or during startup, preventing direct metal-to-metal contact caused by insufficient oil film formation at low speeds.

[0026] This invention optimizes the structure of a four-pad tilting radial sliding bearing, improving its load-bearing capacity, increasing oil film thickness, and reducing pad metal temperature. It ensures that bearing pad temperature and unit vibration are within design requirements, meeting the actual needs of the bearing to withstand some of the unit's lateral loads, improving the problem of abnormal bearing pad wear, and enhancing the stability of unit operation.

[0027] This invention overcomes the inherent defects of traditional symmetrical supports through the synergistic design of eccentric fulcrum, asymmetrical oil wedge, and spring preload, significantly improving anti-eccentric load capacity and operational stability, making it suitable for high-load conditions in ultra-supercritical steam turbines. It optimizes load distribution and oil film dynamics, solving the temperature difference and wear problems of traditional symmetrical bearings, and is applicable to high-load conditions in ultra-supercritical units. Attached Figure Description

[0028] Figure 1 This is a cross-sectional view of the bearing of this utility model;

[0029] Figure 2 It is an oil wedge diagram supporting the upper bearing block;

[0030] Figure 3 This is a longitudinal sectional view of the bearing of this utility model;

[0031] Figure 4 This is a schematic diagram of the bearing housing structure;

[0032] Figure 5 This is a schematic diagram of the structure supporting the upper tile;

[0033] Figure 6 yes Figure 1A magnified view of part B in the image;

[0034] In the diagram: 1. Bearing housing, 2. Upper support pad, 3. Lower support pad, 4. Stop pin, 5. Shim set, 6. Cylindrical pad, 7. Adjusting pad, 8. Support pin, 9. Spring, 10. First oil seal ring, 11. Check valve, 12. Second oil seal ring, 13. Oil supply port. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate this utility model, but are not intended to limit the scope of this utility model. Specific implementation method one:

[0037] Combination Figure 1 — Figure 6 This embodiment describes a tilting pad radial off-center bearing for an ultra-supercritical steam turbine unit, comprising a bearing housing 1, and further comprising a set of support pads, support pins 8, and adjusting pads 7.

[0038] A set of support pads forms a support part. The set of support pads is connected to the bearing housing 1 through support pins 8 and adjusting pads 7 to achieve point support. The set of support pads is arranged end to end on the inner side of the bearing housing 1.

[0039] A set of support pads consists of four pads, which are composed of two upper support pads 2 and two lower support pads 3. The support points of the two upper support pads 2 and the two lower support pads 3 are located at 45° from the midpoint of the upper and lower halves of the bearing housing 1, respectively.

[0040] The tilting pad radial off-center load bearing for ultra-supercritical steam turbine units consists of two parts: support and auxiliary. The support part adopts a four-pad tilting pad structure with two upper support pads 2 and two lower support pads 3.

[0041] The support points of the upper support pad 2 and the two lower support pads 3 are located at 45° from the midpoint of the upper and lower halves of the bearing housing 1, respectively. The upper support pad 2 and the two lower support pads 3 are supported by support pins 8 and adjusting pads 7 to ensure that the pads automatically adjust with the rotor center during unit operation.

[0042] The relative position of the bearing pad support is Lc / L=0.6 (Lc is the arc length of the bearing pad support position, and L is the arc length of the bearing pad), which allows the bearing to bear part of the lateral load; an oil supply port 13 is provided between the bearing pads, which can effectively ensure that the bearing is fully lubricated, and the angle A between the oil supply port 13 and the bearing centerline is 7.5°. Specific Implementation Method Two:

[0044] Combination Figure 1 — Figure 6 This embodiment describes a tilting pad radial off-center bearing for an ultra-supercritical steam turbine unit. An oil supply port 13 is provided between the upper support pad 2 and the lower support pad 3. The angle between the oil supply port 13 and the centerline of the bearing housing 1 is A, and the angle A is 7.5°.

[0045] The upper support pad 2 and the lower support pad 3 are connected to the bearing housing 1 via support pins 8, which are rigidly fixed to the bearing housing 1. Adjusting shims 7 are installed between the support pins 8 and the pads to adjust the pad clearance. The pads can freely swing around the support pins 8 at a small angle to adapt to changes in rotor load. Specific implementation method three:

[0047] Combination Figure 1 — Figure 6 This embodiment describes a tilting pad radial eccentric bearing for an ultra-supercritical steam turbine unit. The relative positions of the fulcrums of the two upper support pads 2 and the two lower support pads 3 are Lc and L, respectively, where Lc / L = 0.6.

[0048] Where Lc is the arc length of the fulcrum position of the tile, and L is the arc length of the tile.

[0049] The fulcrum positions of the upper support tile 2 and the two lower support tiles 3 are offset by Lc / L=0.6 to enhance the resistance to eccentric loads.

[0050] The bearing housing 1 is an outer shell structure, mainly used to fix the bearing pads and provide an installation reference. The upper support pad 2 and two lower support pads 3 can swing around a fulcrum to adapt to load changes. The support pin 8 is used to connect the bearing pads to the bearing housing 1, serving as a swing fulcrum. The adjusting shim 7 is used to fine-tune the position of the bearing pads to ensure alignment accuracy. Specific implementation method four:

[0052] Combination Figure 1 — Figure 6 This embodiment describes a tilting radial off-center bearing for an ultra-supercritical steam turbine unit. A spring 9 is provided between the upper support pad 2 and the bearing housing 1. The upper support pad 2 is connected to the bearing housing 1 through the spring 9, and the spring 9 is provided to make the upper support pad 2 contact the rotor.

[0053] Spring 9 is only equipped on the upper support pad, and applies preload to ensure rotor contact. One end of spring 9 is fixed to bearing housing 1, and the other end abuts against the upper support pad 2. By setting spring 9 to provide preload, the rotor is ensured to contact the pad at low speed or during startup, avoiding dry friction. Specific implementation method five:

[0055] Combination Figure 1 — Figure 6 This embodiment describes a tilting pad radial off-center bearing for an ultra-supercritical steam turbine unit. The oil wedge of the upper support pad 2 is arc-shaped, and the oil wedge of the upper support pad 2 is not concentric with the bearing centerline of the bearing housing 1. Specific implementation method six:

[0057] Combination Figure 1 — Figure 6 This embodiment describes a tilting pad radial eccentric bearing for an ultra-supercritical steam turbine unit. The tilting pad radial eccentric bearing for an ultra-supercritical steam turbine unit further includes cylindrical pads 6 and shim sets 5.

[0058] The tilting pad radial off-center load bearing of the ultra-supercritical steam turbine unit is supported on the bearing housing bearing seat by cylindrical pad 6 and shim group 5.

[0059] The gasket set 5 is set in the outer groove of the bearing housing 1, and the cylindrical pad 6 presses the gasket set 5 into the groove of the bearing housing 1. The gasket set 5 adjusts the vertical and horizontal position of the tilting pad radial off-center bearing for ultra-supercritical steam turbine units.

[0060] The cylindrical pad 6 and the shim set 5 are used together to adjust the position of the bearing in the bearing housing. The stop pin 4 restricts the axial rotational freedom of the bearing.

[0061] The outer cylindrical surface of the cylindrical pad 6 has a slightly smaller clearance fit diameter with the inner hole of the bearing housing. The bearing alignment position is adjusted by the shim set 5. Specific implementation method seven:

[0063] Combination Figure 1 — Figure 6 This embodiment describes a tilting pad radial off-center bearing for an ultra-supercritical steam turbine unit. The diameter of the cylindrical pad 6 is larger than the diameter of the bearing housing 1. The upper surface of the cylindrical pad 6 has a groove, and the groove on the cylindrical pad 6 restricts the axial degree of freedom of the tilting pad radial off-center bearing for the ultra-supercritical steam turbine unit. Detailed implementation method eight:

[0065] Combination Figure 1 — Figure 6 This embodiment describes a tilting pad radial eccentric bearing for an ultra-supercritical steam turbine unit, which further includes a stop pin 4.

[0066] The stop pin 4 is connected to the bearing housing 1. The stop pin 4 is lower than the horizontal split surface of the bearing housing 1. The side of the stop pin 4 away from the bearing housing 1 extends into a groove in the bearing housing bearing seat, thereby constraining the axial rotational freedom of the bearing.

[0067] The stop pin 4 extends from the bearing housing 1 and is inserted into the bearing seat groove. Its functions are: the cylindrical pad 6 allows radial floating to accommodate thermal expansion; and the stop pin 4 restricts the rotation of the bearing. Specific implementation method nine:

[0069] Combination Figure 1 — Figure 6 This embodiment describes a tilting pad radial eccentric bearing for an ultra-supercritical steam turbine unit. The tilting pad radial eccentric bearing for an ultra-supercritical steam turbine unit further includes a first oil seal ring 10, a second oil seal ring 12, and a check valve 11.

[0070] The first oil seal ring 10 and the second oil seal ring 12 are fastened to both sides of the bearing housing 1 by screws. The check valve 11 is integrated in the top shaft connector and is located at the inlet of the top shaft oil line.

[0071] The check valve 11 can improve the bearing wear phenomenon caused by the destruction of the oil film due to the lubricating oil being forced into the top shaft oil line during bearing operation.

[0072] The first oil seal ring 10 and the second oil seal ring 12 prevent lubricating oil leakage. The check valve 11 prevents lubricating oil from flowing back into the top shaft oil circuit and protects the oil film. Specific Implementation Method Ten:

[0074] Combination Figure 1 — Figure 6 This embodiment describes a tilting pad radial eccentric bearing for an ultra-supercritical steam turbine unit. The first oil seal ring 10, the second oil seal ring 12, and the check valve 11 constitute the auxiliary part of the tilting pad radial eccentric bearing for an ultra-supercritical steam turbine unit.

[0075] Working principle

[0076] (1) Oil film formation and lubrication

[0077] Oil supply system: Lubricating oil is injected into the gap between the bearing and the rotor from the oil supply port at an angle A=7.5° to form a dynamic oil film.

[0078] The eccentric fulcrum Lc / L=0.6 lengthens the oil wedge convergence zone. Figure 2 The increased oil film thickness reduces friction and temperature rise.

[0079] Non-concentric circular arc oil wedge: The oil wedge of the upper support pad 2 is offset from the bearing centerline, which enhances the uniformity of oil film pressure distribution.

[0080] (2) Load distribution and adaptive adjustment:

[0081] Handling lateral loads:

[0082] When the rotor is subjected to lateral forces such as steam force or vibration, the bearing pads automatically tilt around the fulcrum to adjust the oil film pressure distribution. The 0.6 arc length offset of the fulcrum makes the bearing tail of the bearing pad stronger and avoids the local overload problem of traditional symmetrical support of 0.5.

[0083] Spring preload: The spring 9 supporting the upper bearing 2 ensures that the rotor is always in contact with the bearing and prevents the oil film from being interrupted.

[0084] (3) Vibration-resistant design:

[0085] The tilting pad structure absorbs rotor vibration, and the pivot offset suppresses oil film oscillation. Check valve 11 prevents lubricating oil backflow and avoids sudden oil film rupture.

[0086] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to a preferred embodiment, it is not intended to limit the present utility model. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present utility model's technical solution. Any simple modifications, equivalent substitutions, and improvements made to the above embodiments without departing from the scope of the present utility model's technical solution, based on the technical essence of the present utility model and within the spirit and principles of the present utility model, shall still fall within the protection scope of the present utility model's technical solution.

Claims

1. A tilting pad radial eccentric bearing for ultra-supercritical steam turbine units, comprising a bearing housing (1), characterized in that, The tilting pad radial off-center bearing for ultra-supercritical steam turbine units also includes a set of support pads, support pins (8) and adjusting pads (7). A set of support pads forms a support part. The set of support pads is connected to the bearing housing (1) by support pins (8) and adjusting pads (7) to achieve point support. The set of support pads is arranged end to end on the inner side of the bearing housing (1). The number of support pads in a set is four, and the four support pads consist of two upper support pads (2) and two lower support pads (3). The support points of the two upper support pads (2) and the two lower support pads (3) are located at 45° from the midpoint of the upper and lower halves of the bearing housing (1).

2. The tilting pad radial eccentric bearing for ultra-supercritical steam turbine units according to claim 1, characterized in that, An oil supply port (13) is provided between the upper support pad (2) and the lower support pad (3). The angle between the oil supply port (13) and the center line of the bearing housing (1) is A, and the angle A is 7.5°.

3. The tilting pad radial eccentric bearing for ultra-supercritical steam turbine units according to claim 2, characterized in that, The relative positions of the fulcrums of the two upper supporting tiles (2) and the two lower supporting tiles (3) are Lc and L, respectively, and Lc / L = 0.6; Where Lc is the arc length of the fulcrum position of the tile, and L is the arc length of the tile.

4. The tilting pad radial eccentric bearing for ultra-supercritical steam turbine units according to claim 2, characterized in that, A spring (9) is provided between the upper support pad (2) and the bearing housing (1). The upper support pad (2) is connected to the bearing housing (1) through the spring (9). The spring (9) is provided to make the upper support pad (2) contact the rotor.

5. The tilting pad radial eccentric bearing for ultra-supercritical steam turbine units according to claim 3 or 4, characterized in that, The oil wedge of the upper support pad (2) is arc-shaped, and the oil wedge of the upper support pad (2) is not concentric with the bearing center line of the bearing housing (1).

6. The tilting pad radial eccentric bearing for ultra-supercritical steam turbine units according to claim 1, characterized in that, The tilting pad radial eccentric bearing for ultra-supercritical steam turbine units also includes cylindrical pads (6) and a set of shims (5). The tilting pad radial eccentric bearing of the ultra-supercritical steam turbine unit is supported on the bearing housing bearing seat by cylindrical pads (6) and shim group (5); The gasket group (5) is set in the outer groove of the bearing housing (1), and the cylindrical pad (6) presses the gasket group (5) into the groove of the bearing housing (1). The gasket group (5) adjusts the vertical and horizontal position of the tilting pad radial off-center bearing for ultra-supercritical steam turbine units.

7. The tilting pad radial eccentric bearing for ultra-supercritical steam turbine units according to claim 6, characterized in that, The diameter of the cylindrical pad (6) is larger than the diameter of the bearing housing (1). The upper surface of the cylindrical pad (6) has a groove, and the groove on the cylindrical pad (6) restricts the axial degree of freedom of the tilting pad radial off-center bearing for ultra-supercritical steam turbine units.

8. The tilting pad radial eccentric bearing for ultra-supercritical steam turbine units according to claim 6, characterized in that, The tilting pad radial eccentric bearing for ultra-supercritical steam turbine units also includes a stop pin (4). The stop pin (4) is connected to the bearing housing (1). The stop pin (4) is lower than the horizontal split surface of the bearing housing (1). The side of the stop pin (4) away from the bearing housing (1) extends into a groove in the bearing seat of the bearing box, thereby constraining the axial rotational freedom of the bearing.

9. The tilting pad radial eccentric bearing for ultra-supercritical steam turbine units according to claim 1, characterized in that, The tilting pad radial off-center bearing for ultra-supercritical steam turbine units also includes a first oil seal ring (10), a second oil seal ring (12), and a check valve (11). The first oil seal ring (10) and the second oil seal ring (12) are fastened to both sides of the bearing housing (1) by screws. The check valve (11) is integrated in the top shaft connector and is located at the inlet of the top shaft oil line.

10. The tilting pad radial eccentric bearing for ultra-supercritical steam turbine units according to claim 9, characterized in that, The first oil seal ring (10), the second oil seal ring (12), and the check valve (11) constitute the auxiliary part of the tilting pad radial off-center bearing for ultra-supercritical steam turbine units.

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