A radial bearing combined surface oil-proof sealing structure for a bulb tubular unit

Abstract

The utility model discloses a kind of radial bearing combination surface anti-seepage oil seal structure for bulb tubular unit, it is related to bearing sealing technical field, and its technical scheme main point is: including radial bearing body, annular groove is opened in the end outer side of radial bearing combination surface body, section of radial bearing body is equipped with combination surface, combination surface is divided into first installation combination surface and second installation combination surface by bearing link end, bolt hole is opened in first installation combination surface and second installation combination surface, square sealing groove is equipped on first installation combination surface, effect is thoroughly eliminated radial bearing in static pressure start-stop operating condition lubricating oil is to the combination surface by annular groove, especially the leakage path of exposed section, to eradicate the risk of oil misting pollution generator winding, experiment proves that the structure not only makes combination surface oil seepage amount to be zero, more makes stator bar life be significantly improved.

Description

Technical Field

[0001] This utility model relates to the field of bearing sealing technology, and more specifically, it relates to an oil-proof sealing structure for the radial bearing assembly surface of a bulb turbine unit. Background Technology

[0002] In bulb turbine generator sets, radial bearings are key components, employing a split-structure design and relying on hydrostatic start-stop and hydrodynamic operation modes. However, existing technologies for such radial bearings generally suffer from the technical challenge of oil leakage at the assembly surface, especially in horizontal units (such as the 15MW unit of the Shangshipan Hydropower Station, commissioned in 2016), where the oil leakage problem is severe.

[0003] The root cause lies in the lack of a dedicated sealing groove designed for the assembly surface (approximately 300mm of which is exposed outside the oil tank), relying solely on flat pressing and bolt tightening. Actual operation shows that this structure cannot completely eliminate the gap in the assembly seam; the gap is typically ≥0.03mm. This causes lubricating oil to seep outward from the annular groove inside the radial bearing under oil pressure, especially the static pressure during unit start-up and shutdown. Under the forced ventilation cooling conditions of the unit, the seeping oil is atomized and diffused into the generator by the high-speed airflow, adhering to the surface of key insulating components such as stator bars and rotor magnetic pole coils over a long period and accumulating downwards, severely eroding their insulation performance, significantly reducing equipment lifespan, and posing a continuous safety hazard.

[0004] Therefore, in order to solve the above-mentioned technical problems, this application proposes an oil-proof sealing structure for the radial bearing assembly surface of a bulb-type air conditioning unit. Utility Model Content

[0005] In view of the shortcomings of the existing technology, the purpose of this utility model is to provide an oil-proof sealing structure for the radial bearing assembly surface of a bulb-type air handling unit.

[0006] To achieve the above objectives, this utility model provides the following technical solution: an oil-proof sealing structure for the radial bearing assembly surface of a bulb turbine unit, comprising a radial bearing body, an annular groove on the outer side of the end of the radial bearing body, a bearing connecting end on the radial bearing body, and an assembly surface at the cross-section of the radial bearing body, the assembly surface being divided into a first mounting assembly surface and a second mounting assembly surface by the bearing connecting end, bolt holes being provided on both the first and second mounting assembly surfaces, and a square sealing groove being provided on the first mounting assembly surface.

[0007] Preferably, the square sealing groove is square and covers the first mounting assembly surface, and in sequence from the installation direction are the first sealing groove, the second sealing groove, and the third sealing groove.

[0008] Preferably, the outer side of the radial bearing body is provided with a concave groove, and a sealing interface is provided at the connection between the third sealing groove and the concave groove, and the side of the sealing interface has an arc.

[0009] Preferably, the first sealing groove extends vertically from the bearing connection end surface near the radial bearing body cavity to the outside of the bearing connection end away from the radial bearing, the third sealing groove extends vertically from the first mounting assembly surface near the annular groove into the concave groove, and the second sealing groove connects the first sealing groove and the third sealing groove laterally.

[0010] Preferably, the connecting ends of the first sealing groove, the second sealing groove, and the third sealing groove are all provided with arcs to allow for filling gaps for the sealing strip.

[0011] Preferably, the width of the square sealing groove is 7mm and the depth of the sealing strip is 5mm.

[0012] Preferably, the square sealing groove is filled with a sealing strip, the sealing strip is made of oil-resistant material, the sealing strip is a circular sealing strip, and the diameter of the circular sealing strip is 6mm.

[0013] Compared with the prior art, the present invention has the following beneficial effects: In this invention, a continuous square sealing groove structure consisting of first, second, and third sealing grooves is designed on the first mounting surface. This structure, combined with a concave groove and an arc-shaped sealing interface, forms a labyrinthine oil-blocking channel. A 7mm wide and 5mm deep groove is fitted with a 6mm diameter oil-resistant rubber circular sealing strip. After 20% compression deformation to generate a 0.5mm radial preload, high-strength bolts are used for tightening to achieve zero clearance in the assembly joint. This eliminates the leakage path of lubricating oil from the radial bearing to the assembly surface, especially the exposed 300mm section, under static pressure start-stop conditions. This eliminates the risk of oil atomization contaminating the generator windings. Experiments have shown that this structure not only reduces oil leakage at the assembly surface to zero but also significantly improves the lifespan of the stator bars. At the same time, the arc-shaped transition angle design effectively compensates for the impact of the maximum ±0.2mm deflection deformation of the main shaft on the seal integrity. Attached Figure Description

[0014] The accompanying drawings, which are included to provide a further understanding of the present invention and form part of this application, illustrate exemplary embodiments of the present invention and, together with the description thereof, serve to explain the present invention and do not constitute an undue limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 for Figure 1 Enlarged view of point A in the middle; Figure 3This is a schematic diagram of the unmodified structure in this utility model.

[0015] 1. Radial bearing body; 2. Annular groove; 3. First mounting surface; 4. Second mounting surface; 5. Bolt hole; 6. Square sealing groove; 7. First sealing groove; 8. Second sealing groove; 9. Third sealing groove; 10. Concave groove; 11. Sealing interface; 12. Bearing connection end. Detailed Implementation

[0016] like Figures 1-3 As shown, this utility model provides an oil-proof sealing structure for the radial bearing assembly surface of a bulb turbine unit, including a radial bearing body 1, an annular groove 2 on the outer side of the end of the radial bearing body 1, a bearing connecting end 12 on the radial bearing body 1, and an assembly surface at the cross section of the radial bearing body 1. The assembly surface is divided into a first mounting assembly surface 3 and a second mounting assembly surface 4 by the bearing connecting end 12. Bolt holes 5 are provided on both the first mounting assembly surface 3 and the second mounting assembly surface 4. A square sealing groove 6 is provided on the first mounting assembly surface 3. The square sealing groove 6 has a width of 7mm and a depth of 5mm. The square sealing groove 6 is filled with a sealing strip made of oil-resistant material. The sealing strip is a round sealing strip with a diameter of 6mm. In this embodiment, a continuous square sealing groove 6 with a width of 7mm and a depth of 5mm is machined at the 300mm exposed assembly surface of the oil tank using a CNC milling machine. A Φ6mm nitrile rubber round sealing strip is embedded in the groove, so that its compression deformation reaches 20%, generating a radial preload of 0.5mm. The bolt holes 5 on the assembly surface are fastened with high-strength bolts (torque value 650N·m), so that the gap of the assembly joint is reduced to 0.

[0017] like Figure 3 As shown in the figure, this is the original radial bearing body 1 without improvement. This structure cannot completely eliminate the gap between the assembly seams (the gap between the assembly surfaces is usually ≥0.03mm). As a result, the lubricating oil seeps out from the annular groove 2 inside the radial bearing under the action of oil pressure, especially the static pressure during the start-up and shutdown of the unit. Under the forced ventilation cooling conditions of the unit, the seeping oil is atomized and diffused into the generator by the high-speed airflow. It adheres to the surface of key insulating components such as stator bars and rotor magnetic pole coils for a long time and collects downwards.

[0018] The square sealing groove 6 is square and wraps around the first mounting assembly surface 3. From the installation direction, the first sealing groove 7, the second sealing groove 8 and the third sealing groove 9 are arranged in sequence. The outer side of the radial bearing body 1 is provided with a concave groove 10. The connection between the third sealing groove 9 and the concave groove 10 is provided with a sealing interface 11. The side of the sealing interface 11 has an arc. The first sealing groove 7 extends vertically from the surface of the bearing connection end 12 near the cavity of the radial bearing body 1 to the outside of the bearing connection end 12 away from the radial bearing. The third sealing groove 9 extends vertically from the surface of the first mounting assembly surface 3 near the annular groove 2 to the concave groove 10. The second sealing groove 8 connects the first sealing groove 7 and the third sealing groove 9 laterally. The connecting ends of the first sealing groove 7, the second sealing groove 8 and the third sealing groove 9 are all provided with arcs to leave a filling gap for the sealing strip. It should be noted that the arc transition angle compensates for the spindle deflection deformation (maximum ±0.2mm), keeping the sealing strip continuously pressed. Since the oil leakage is mostly due to the static pressure during the start-up and shutdown phases of the unit, the three sealing grooves located between the annular groove 2 and the concave groove 10 form a labyrinthine oil blocking channel with the sealing interface 11 at the concave groove 10, achieving zero leakage and eliminating oil mist erosion. In this embodiment, the stator bar life is increased to 150,000 hours, which is 2.3 times that before the modification.

[0019] In summary, this utility model designs a continuous square sealing groove 6 structure composed of first, second, and third sealing grooves 9 on the first mounting surface 3. This, combined with a concave groove 10 and an arc-shaped sealing interface 11, forms a labyrinthine oil-blocking channel. A 7mm wide and 5mm deep groove is fitted with a 6mm diameter oil-resistant rubber circular sealing strip. After 20% compression deformation to generate a 0.5mm radial preload, high-strength bolts are used for tightening to achieve zero clearance in the assembly joint. This eliminates the leakage path of lubricating oil from the radial bearing to the assembly surface via the annular groove 2, especially in the exposed 300mm section, under static pressure start-stop conditions. This eliminates the risk of oil atomization contaminating the generator windings. Experiments have shown that this structure not only reduces oil leakage to zero at the assembly surface but also significantly improves the lifespan of the stator bars. Simultaneously, the arc-shaped transition angle design effectively compensates for the impact of the maximum ±0.2mm deflection deformation of the main shaft on the seal integrity.

[0020] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model in any way. Those skilled in the art can readily implement this utility model based on the accompanying drawings and the above description. However, any modifications, alterations, or equivalent variations made by those skilled in the art without departing from the scope of the utility model's technical solution, utilizing the disclosed technical content, are considered equivalent embodiments of this utility model. Furthermore, any equivalent changes, alterations, or variations made to the above embodiments based on the essential technology of this utility model are still within the protection scope of this utility model's technical solution.

Claims

1. An oil-proof sealing structure for the radial bearing assembly surface of a bulb-type turbine unit, comprising a radial bearing body (1), characterized in that: The radial bearing body (1) has an annular groove (2) on its outer side. The radial bearing body (1) has a bearing connection end (12). The cross section of the radial bearing body (1) has a combination surface. The combination surface is divided into a first mounting combination surface (3) and a second mounting combination surface (4) by the bearing connection end (12). Both the first mounting combination surface (3) and the second mounting combination surface (4) have bolt holes (5). The first mounting combination surface (3) has a square sealing groove (6).

2. The oil-proof sealing structure for the radial bearing assembly surface of a bulb-type turbine unit according to claim 1, characterized in that: The square sealing groove (6) is square and covers the first mounting assembly surface (3). From the installation direction, it consists of the first sealing groove (7), the second sealing groove (8), and the third sealing groove (9).

3. The oil-proof sealing structure for the radial bearing assembly surface of a bulb-type turbine unit according to claim 2, characterized in that: The radial bearing body (1) has a concave groove (10) on its outer side, and a sealing interface (11) is provided at the connection between the third sealing groove (9) and the concave groove (10). The side of the sealing interface (11) has an arc.

4. The oil-proof sealing structure for the radial bearing assembly surface of a bulb-type turbine unit according to claim 3, characterized in that: The first sealing groove (7) extends vertically from the surface of the bearing connection end (12) near the cavity of the radial bearing body (1) to the outside of the bearing connection end (12) away from the radial bearing. The third sealing groove (9) extends vertically from the surface of the first mounting assembly surface (3) near the annular groove (2) to the concave groove (10). The second sealing groove (8) connects the first sealing groove (7) and the third sealing groove (9) laterally.

5. The oil-proof sealing structure for the radial bearing assembly surface of a bulb-type turbine unit according to claim 4, characterized in that: The interconnecting ends of the first sealing groove (7), the second sealing groove (8) and the third sealing groove (9) are all provided with arcs to leave gaps for the sealing strip.

6. The oil-proof sealing structure for the radial bearing assembly surface of a bulb-type turbine unit according to claim 5, characterized in that: The width of the square sealing groove (6) is 7mm, and the depth of the sealing strip is 5mm.

7. The oil-proof sealing structure for the radial bearing assembly surface of a bulb-type turbine unit according to claim 6, characterized in that: The square sealing groove (6) is filled with a sealing strip. The sealing strip is made of oil-resistant material and is a circular sealing strip with a diameter of 6 mm.

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