Bearing gas sealing structure based on double annular pressure stabilizing cavities
By designing a bearing gas sealing structure based on a double annular pressure stabilization chamber, the problem of uneven bearing sealing when the gas supply of its own gas source in underwater impeller machinery is solved, and uniform distribution of circumferential static pressure of the bearing and stable lubrication of lubricating oil are achieved.
Patent Information
- Application Number
- CN202510553798.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-29
- Publication Date
- 2025-08-01
AI Technical Summary
In underwater impeller machinery, when the gas is supplied with its own gas source, it is difficult to distribute the tight air evenly and stably along the entire circle of the bearing, resulting in poor oil leakage and tight sealing effect.
The bearing gas sealing structure based on the double annular pressure stabilization chamber is adopted, including an intake passage, a first annular pressure stabilization chamber, an intermediary slit flow passage, a second annular pressure stabilization chamber and annular sealing chamber. By designing a reasonable cross-sectional shape and connection method, a uniform static pressure distribution along the circumferential direction is formed.
Under the conditions of gas supply with its own gas source, the stable lubrication and uniform static pressure distribution of lubricants in various positions in the bearing circumference are achieved, which improves the tight sealing effect of the bearing.
Smart Images
Figure CN120402532A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of bearing sealing structures of impeller machinery, and in particular relates to a bearing gas sealing structure of underwater impeller machinery with its own air source for gas supply. Background Art
[0002] Bearings are essential components in turbomachinery. They withstand radial and axial loads from rotating parts, providing stable support for the rotating components. They also reduce friction between rotating and stationary components, maintaining the rotating components' rotational accuracy. Lubricating oil plays a key role in bearing operation. In addition to reducing friction between bearing components and reducing heat and wear due to friction, it also provides cooling and cleaning functions. During bearing operation, lubricating oil may leak, causing the bearing's operating temperature to rise and surface damage to occur, shortening the bearing's service life. In severe cases, this can lead to component damage and even accidents. Therefore, to effectively prevent bearing oil leakage, sealing measures must be implemented.
[0003] Bearing sealing technologies can be categorized as contact sealing or non-contact sealing. Contact sealing uses a sealing surface made of graphite or other materials, which deforms to create a certain sealing pressure to achieve a seal. However, when the impeller rotates at high speeds, the contact sealing structure will wear rapidly during rotation, affecting the sealing effect. Therefore, high-speed impellers often require non-contact sealing.
[0004] Gas sealing is a commonly used non-contact sealing structure. Existing gas sealing technology primarily involves introducing external air through the mechanical system's own air system, compressing it to increase the gas pressure, and then introducing it into the bearing sealing cavity to achieve a gas seal. However, when the impeller machine is operating underwater, without outside air, the bearing sealing gas can only be supplied from a built-in gas source, such as a gas cylinder. Limited by factors such as the gas storage capacity of the gas source and pressure loss in the gas supply pipeline, the air supplied to the sealing cavity by the built-in gas source is difficult to distribute evenly around the entire circumference of the bearing as when using external air. This can cause lubricating oil to leak in areas where the sealing gas distribution is insufficient. Furthermore, since the flow rate of the built-in gas source is typically high, the sealing gas enters the sealing cavity with high dynamic pressure and low and unstable static pressure. Since the use of a built-in gas source relies on the static pressure of the sealing gas to achieve a sealing effect on the lubricating oil level, the insufficient and unstable static pressure of the sealing gas can also affect the overall sealing effect of the bearing. Therefore, in order to seal the impeller machinery bearings under the condition of no external air underwater, there is an urgent need for a bearing gas sealing structure that can provide a uniform and stable sealing effect along the entire circumference of the bearing when using its own air source. Summary of the Invention
[0005] In view of this, in order to solve the problem of how to design a bearing gas sealing structure that can provide a uniform and stable sealing effect along the entire circumference of the bearing when using its own gas source for air supply, the present invention proposes a bearing gas sealing structure based on a dual-ring pressure stabilizing chamber.
[0006] To achieve the above object, the present invention adopts the following technical solutions: A bearing gas sealing structure based on a dual-ring pressure stabilizing chamber, comprising an air inlet flow channel, a first-ring pressure stabilizing chamber, an intermediate slit flow channel, a second-ring pressure stabilizing chamber, and an annular sealing chamber. The annular sealing chamber is connected to the outlet of the second-ring pressure stabilizing chamber. The inlet of the second-ring pressure stabilizing chamber is connected to the outlet of the intermediate slit flow channel. The inlet of the intermediate slit flow channel is connected to the outlet of the first-ring pressure stabilizing chamber. The inlet of the first-ring pressure stabilizing chamber is connected to the outlet of the air inlet flow channel 1, and the outlet of the air inlet flow channel is tangent to the first-ring pressure stabilizing chamber.
[0007] Furthermore, the inlet cross-section and the outlet cross-section of the air inlet flow channel are circular with the same diameter, and the inlet section and the outlet section are connected by a smooth curved surface. For the inlet section of the air inlet flow channel: when the gas source is connected to the flow channel inlet through a pipeline, the diameter d1 of the flow channel inlet cross-section is equal to the diameter of the outlet cross-section of the gas supply pipeline; when the gas source is connected to the air inlet flow channel inlet through a flow channel hole opened on the casing, the diameter d1 of the flow channel inlet cross-section is α1 times the diameter of the outlet cross-section of the casing flow channel hole, where 1 < α1 ≤ 1.3.
[0008] Furthermore, the cross-sectional shape of the first-ring pressure stabilizing chamber is circular, or a combination of a semi-circle and a rectangle that is smoothly tangent to it. The selection principle of the cross-sectional shape is: if the sealing gas supply pressure is not greater than times the estimated bearing lubricating oil leakage surface pressure, the cross-sectional shape is selected as circular or a combination of a circle and a rectangle that is smoothly tangent to it; conversely, if the supply pressure is greater than 3 times the estimated bearing lubricating oil leakage surface pressure, the cross-sectional shape is circular.
[0009] Furthermore, when the cross-section of the first-ring pressure stabilizing chamber is circular, the diameter d2 is α2 times the diameter d1 of the air inlet flow channel cross-section, where 1.0 ≤ α2 ≤ 1.2; when the cross-section of the first-ring pressure stabilizing chamber is a smooth tangent combination of a semi-circle and a rectangle, the circular diameter d2 remains unchanged, the width w1 of the rectangle is equal to d2, and the height h1 is α3 times w1, where 1.0 ≤ α3 ≤ 1.25.
[0010] Furthermore, the cross-section of the intermediate slit flow channel is rectangular, and the center line of the cross-section is coplanar with the center lines of the first and second-ring pressure stabilizing chambers. The height h2 of the rectangle is α4 times the semi-circle diameter d2 of the first-ring pressure stabilizing chamber cross-section, and the width w2 of the rectangle is α5 times d2, where 0.15 < α4 ≤ 0.3 and 0.15 < α5 < 0.8.
[0011] Furthermore, the cross-sectional shape of the second-ring pressure stabilizing chamber is circular or rectangular.
[0012] Further, the height h3 of the rectangular cross-section of the second annular constant-pressure chamber is α6 times the annular sealing height h4, where 4 < α6 ≤ 7.5, and the width w3 of the rectangle is α7 times the diameter d2 of the first annular constant-pressure chamber, where 0.7 < α7 ≤ 1.3.
[0013] Further, the cross-sectional shape of the annular sealing chamber is rectangular, and its width is determined by the actual installation structure of the sealing component and the bearing, and its height h4 ≤ 0.25 mm.
[0014] Compared with the prior art, the beneficial effects of the bearing gas sealing structure based on a double annular constant-pressure chamber of the present invention are as follows:
[0015] 1. For the first annular constant-pressure chamber of the present invention, its cross-sectional area is larger than that of the air inlet flow channel. According to the continuity equation and Bernoulli's equation, the axial velocity of the sealing gas in the first annular constant-pressure chamber decreases, resulting in a preliminary increase in static pressure; at the same time, the annular structure forces the sealing gas flowing out of the air inlet flow channel unidirectionally to redistribute its momentum circumferentially, forming a preliminary circumferential flow. The proposed intermediate slit flow channel further forces the sealing gas in the first annular constant-pressure chamber to redistribute its momentum radially, forming a radially circumferentially uniform flow.
[0016] 2. For the second annular constant-pressure chamber of the present invention, by expanding the cross-sectional area of the sealing gas flowing out of the intermediate slit flow channel, the radial flow velocity of the sealing gas decreases, and the static pressure is further increased; at the same time, since its height is greater than the sealing surface height, the residence time of the sealing gas in the chamber is extended, and the viscous dissipation effect further eliminates the residual velocity gradient, finally forming a circumferentially uniform static pressure distribution.
[0017] 3. Under the combined action of the first and second annular constant-pressure chambers of the present invention, the sealing gas entering the annular sealing chamber has sufficient and uniform static pressure circumferentially, and can achieve stable lubrication of the lubricating oil at each position in the circumferential direction of the bearing under the condition of single-strand air inlet of the gas source. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The accompanying drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:
[0019] Figure 1 is a schematic structural diagram of the bearing gas sealing structure based on a double annular constant-pressure chamber of the present invention, where a is a schematic diagram of the physical structure, and b is a schematic diagram of the fluid domain (the shape of the chamber) structure;
[0020] Figure 2 is the front view of the fluid domain;
[0021] Figure 3A sectional side view of the bearing gas sealing structure based on the double-ring constant-pressure cavity;
[0022] Figure 4 A usage case of the bearing gas sealing structure based on the double-ring constant-pressure cavity in bearing sealing;
[0023] Figure 5 For Figure 4 A partial enlarged view of the structure proposed in the case.
[0024] The structures or components shown in the figure are respectively: 1 - intake air flow channel, 2 - first-ring constant-pressure cavity, 3 - intermediate slit flow channel, 4 - second-ring constant-pressure cavity, 5 - annular sealing cavity, 6 - bearing lubricating oil leakage interface, 7 - bearing gland, 8 - shaft surface sealing fitting, 9 - gas source supply pipeline, 10 - engine lubricating oil supply pipeline, 11 - lubricating oil injector, 12 - engine lubricating oil return pipeline, 13 - bearing, 14 - the bearing gas sealing structure of the present invention. Specific implementation manner
[0025] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.
[0026] See Figures 1-5 Describing this embodiment, a bearing gas sealing structure based on a double-ring constant-pressure cavity includes an intake air flow channel 1, a first-ring constant-pressure cavity 2, an intermediate slit flow channel 3, a second-ring constant-pressure cavity 4, and an annular sealing cavity 5. The annular sealing cavity 5 is connected to the outlet of the second-ring constant-pressure cavity 4. The inlet of the second-ring constant-pressure cavity 4 is connected to the outlet of the intermediate slit flow channel 3. The inlet of the intermediate slit flow channel 3 is connected to the outlet of the first-ring constant-pressure cavity 2. The inlet of the first-ring constant-pressure cavity 2 is connected to the outlet of the intake air flow channel 1, and the outlet of the intake air flow channel 1 is tangent to the first-ring constant-pressure cavity 2.
[0027] The inlet section and the outlet section of the inlet air flow passage 1 are circular with the same diameter. The inlet section and the outlet section are connected by a smooth curved surface to reduce the pressure loss during the flow of the sealing air. For the inlet section of the flow passage: when the air source is connected to the inlet of the flow passage through a pipeline, the diameter d1 of the inlet section of the flow passage is equal to the diameter of the outlet section of the supply pipeline 9; when the air source is connected to the inlet of the inlet air flow passage 1 through a flow passage hole opened on the casing, the diameter d1 of the inlet section of the flow passage is α1 times the diameter of the outlet section of the casing flow passage hole, where 1 < α1 ≤ 1.3. If α1 is too large or too small, it will increase the pressure loss when the sealing air enters the flow passage. The axis of the middle section of the inlet air flow passage can be a straight line, an arc or a smooth spline curve, but non-smooth corners should be avoided. In order to reduce the pressure loss when the sealing air enters the first annular pressure stabilizing cavity, the outlet section of the inlet air flow passage is tangent to the first annular pressure stabilizing cavity.
[0028] The cross-sectional shape of the first annular pressure stabilizing cavity 2 is circular, or a combination of a semi-circle and a rectangle that is smoothly tangent to it. The selection principle of the cross-sectional shape is as follows: if the supply pressure of the sealing air is not greater than 3 times the estimated pressure of the bearing lubricating oil leakage surface, neither of the two cross-sectional shapes will cause a large pressure loss to the sealing air, that is, the cross-sectional shape can be selected as circular or a combination of a rectangle that is smoothly tangent to it; conversely, if the supply pressure is greater than 3 times the estimated pressure of the bearing lubricating oil leakage surface, the cross-sectional shape is circular to ensure that no excessive pressure loss of the sealing air occurs. The determination method of the cross-sectional geometric dimensions is as follows: if the cavity cross-section is circular, the diameter d2 is α2 times the diameter d1 of the inlet air flow passage cross-section, where 1.0 ≤ α2 ≤ 1.2; if the cavity cross-section is a smooth tangent combination of a semi-circle and a rectangle, the circular diameter d2 remains unchanged, the width w1 of the rectangle is equal to d2, and the height h1 is α3 times w1, where 1.0 ≤ α3 ≤ 1.25.
[0029] The intermediate slit flow passage 3 between the first and second pressure stabilizing cavities has a rectangular cross-section, and the center line of the cross-section is coplanar with the center lines of the cross-sections of the first and second annular pressure stabilizations. The height h2 of the rectangle is α4 times the semi-circle diameter d2 of the cross-section of the first pressure stabilizing cavity, and the width w2 of the rectangle is α5 times d2, where 0.15 < α4 ≤ 0.3 and 0.15 < α5 < 0.8.
[0030] For the cross-sectional shape of the second annular pressure stabilizing cavity 4, a circular cross-section or a rectangular cross-section can be selected. However, since the dynamic pressure of the sealing air has been reduced when it enters the second pressure stabilizing cavity, using a circular cross-section has no advantage in reducing the pressure loss. And a rectangular cross-section has a larger area under the same width, which can increase the mixing space of the sealing air in the cavity. Therefore, a rectangular cross-section is recommended. The determination method of the geometric dimensions of the rectangular cross-section is as follows: the height h3 of the rectangle is α6 times the annular sealing height h4, where 4 < α6 ≤ 7.5, and the width w3 of the rectangle is α7 times the diameter d2 of the first annular pressure stabilizing cavity, where 0.7 < α7 ≤ 1.3.
[0031] The annular seal cavity 5 is the cavity where the sealing effect is generated between the sealing gas and the seal. The cross-sectional shape of the annular seal cavity 5 is rectangular, and its width is determined by the actual installation structure of the sealing component and the bearing. However, its height h4 is recommended to be no more than 0.25 mm to ensure the sealing quality.
[0032] Embodiment 1:
[0033] In Figure 5 In the shown application example, the lubricating oil reaches the lubricating oil injector 11 through the engine lubricating oil supply pipeline 10, and the lubricating oil is transported to the cavity of the bearing 13 for bearing lubrication. The excess lubricating oil returns to the lubricating oil tank through the engine oil return pipeline 12.
[0034] A bearing gas sealing structure 14 based on a double annular pressure stabilizing cavity opened in the bearing gland is composed of an air inlet flow channel 1 in the gland 7, a first annular pressure stabilizing cavity 2, an intermediate slit flow channel 3 between the first and second pressure stabilizing cavities, a second annular pressure stabilizing cavity 4, and an annular seal cavity 5 formed by the inner surface of the gland 7 and the shaft and shaft surface sealing fittings 8, so as to generate uniform and sufficient static pressure on the bearing lubricating oil leakage surface 6. One side of the annular seal cavity 5 is connected to the second annular pressure stabilizing cavity 4, and the other side is connected to the bearing lubricating oil leakage point. That is to say, the bearing lubricating oil leakage surface 6 is the side surface of the annular seal cavity 5, and the bearing lubricating oil leakage surface 6 is coaxial with the annular seal cavity 5.
[0035] The sealing gas enters the air inlet flow channel 1 in the gland 7 through the gas source supply pipeline 9, and the supply pipeline 9 is connected to the gland 7 by welding.
[0036] The inlet cross-section and the outlet cross-section of the air inlet flow channel 1 are connected by a smooth curved surface, and the diameters d1 of the inlet and outlet cross-sections of the air inlet flow channel are the same as the diameter of the supply pipeline 8.
[0037] The cross-sectional shape of the first annular pressure stabilizing cavity 2 is a combination of a semi-circle and a rectangle tangent to the semi-circle. The diameter d2 of the semi-circle is 1.0 times of d1, and the width w1 and height h1 of the rectangle are both equal to d2.
[0038] The intermediate slit flow channel 3 between the first and second pressure stabilizing cavities has a rectangular cross-section, and the cavity axis is coplanar with the axis of the first annular pressure stabilizing cavity 2. The height h2 of the rectangle is 0.2 times of the semi-circle diameter d2 of the first pressure stabilizing cavity cross-section, and the width w2 of the rectangle is 0.2 times of d2.
[0039] The cross-sectional shape of the second annular pressure stabilizing cavity 4 is rectangular, and the cavity axis is coplanar with the axis of the intermediate slit flow channel 3. The height h3 of the rectangle is 5.0 times of the height h4 of the annular seal cavity, and the width w3 of the rectangle is equal to the diameter d2 of the first annular pressure stabilizing cavity.
[0040] The embodiments of the present invention disclosed above are only used to help illustrate the present invention. The embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. According to the content of this specification, many modifications and variations can be made. These embodiments are selected and specifically described in this specification to better explain the principles and practical applications of the present invention, so that those skilled in the art can well understand and utilize the present invention.
Claims
1. A bearing gas sealing structure based on a dual-ring voltage-stabilizing cavity, characterized in that: It includes an intake air flow passage (1), a first annular constant pressure chamber (2), an intermediate slit flow passage (3), a second annular constant pressure chamber (4), and an annular sealing chamber (5) arranged in sequence from the inner ring of the outer ring island. The annular sealing chamber (5) is connected to the outlet of the second annular constant pressure chamber (4), the inlet of the second annular constant pressure chamber (4) is connected to the outlet of the intermediate slit flow passage (3), the inlet of the intermediate slit flow passage (3) is connected to the outlet of the first annular constant pressure chamber (2), the inlet of the first annular constant pressure chamber (2) is connected to the outlet of the intake air flow passage (1), and the outlet of the intake air flow passage (1) is tangent to the first annular constant pressure chamber (2).
2. The bearing gas sealing structure based on a dual-ring voltage stabilizing cavity according to claim 1, wherein: The inlet cross-section and the outlet cross-section of the intake air flow passage (1) are circular with the same diameter, and the inlet section and the outlet section are connected by a smooth curved surface. For the inlet section of the intake air flow passage (1): when the gas source is connected to the flow passage inlet through a pipeline, the diameter d1 of the flow passage inlet cross-section is equal to the diameter of the outlet cross-section of the supply pipeline (9); when the gas source is connected to the inlet of the intake air flow passage (1) through a flow passage hole opened on the casing, the diameter d1 of the flow passage inlet cross-section is α1 times the diameter of the outlet cross-section of the casing flow passage hole, where 1 < α1 ≤ 1.
3.
3. The bearing gas sealing structure based on a dual-ring voltage stabilizing cavity according to claim 1, wherein: The cross-sectional shape of the first annular constant pressure chamber (2) is circular, or a combination of a semicircle and a rectangle that is smoothly tangent to it. The selection principle of the cross-sectional shape is: if the supply pressure of the sealing gas is not greater than 3 times the estimated bearing lubricating oil leakage surface pressure, the cross-sectional shape is selected as circular or a combination of a circle and a rectangle that is smoothly tangent to it; conversely, if the supply pressure is greater than 3 times the estimated bearing lubricating oil leakage surface pressure, the cross-sectional shape is circular.
4. The bearing gas sealing structure based on a dual-ring voltage stabilizing cavity according to claim 3, characterized in that: When the cross-section of the first annular constant pressure chamber (2) is circular, the diameter d2 is α2 times the diameter d1 of the intake air flow passage cross-section, where 1.0 ≤ α2 ≤ 1.2; when the cross-section of the first annular constant pressure chamber (2) is a smooth tangent combination of a semicircle and a rectangle, the diameter d2 of the circle remains unchanged, the width w1 of the rectangle is equal to d2, and the height h1 is α3 times w1, where 1.0 ≤ α3 ≤ 1.
25.
5. The bearing gas sealing structure based on a dual-ring voltage stabilizing cavity according to claim 1, characterized in that: The cross-section of the intermediate slit flow passage (3) is rectangular, and the center line of the cross-section is coplanar with the center lines of the first and second annular constant pressure chambers. The height h2 of the rectangle is α4 times the diameter d2 of the semicircle of the cross-section of the first constant pressure chamber, and the width w2 of the rectangle is α5 times d2, where 0.15 < α4 ≤ 0.3 and 0.15 < α5 < 0.
8.
6. The bearing gas sealing structure based on a dual-ring voltage-stabilizing cavity according to claim 1, wherein: The cross-sectional shape of the second annular constant pressure chamber (4) is circular or rectangular.
7. The bearing gas sealing structure based on a dual-ring voltage-stabilizing cavity according to claim 6, wherein: The height h3 of the rectangular cross-section of the second annular constant pressure chamber (4) is α6 times the annular sealing height h4, where 4 < α6 ≤ 7.5, and the width w3 of the rectangle is α7 times the diameter d2 of the first annular constant pressure chamber, where 0.7 < α7 ≤ 1.
3.
8. The bearing gas sealing structure based on a dual-ring voltage-stabilizing cavity according to claim 1, wherein: The cross-sectional shape of the annular sealing chamber (5) is rectangular, and its width is determined by the actual installation structure of the sealing component and the bearing, and its height h4 ≤ 0.25 mm.