Air seal structure for bearing chamber

Abstract

The utility model discloses an air seal structure for a bearing chamber, which comprises a main shaft, a bearing arranged on the main shaft, an inner side cover plate and a bearing seat arranged around the bearing, the inner side cover plate is fixedly connected with the bearing seat, and a first piston ring and a second piston ring are arranged between the inner side cover plate and the main shaft. The piston ring is characterized in that a main gas path is further arranged on the bearing seat, and an inner side branch gas path which is communicated with the main gas path and is guided between the first piston ring and the second piston ring is arranged on the inner side cover plate.

Description

Technical Field

[0001] The utility model belongs to the technical field of mechanical seals, and more specifically relates to a gas seal structure for a bearing chamber. Background Art

[0002] A bearing chamber usually has an oil inlet circuit and an oil return circuit, and is equipped with a seal at the same time. As is well known, when oil is introduced, a certain oil pressure must be applied, otherwise the lubricating oil may not be able to enter the bearing interior. In order to ensure that the rotation of the rotor is not interfered with by the stator, there must be a gap between the rotor and the stator, and various dynamic seals can be installed at this gap. Dynamic seals are divided into two types: contact type and non-contact type.

[0003] An oil seal is a typical contact type dynamic seal. The oil seal is installed on the stator, and a thin oil film will be formed between the flexible lip of the oil seal and the surface of the rotor. This oil film adheres to the lip of the oil seal, and there is no contact at all on both sides of the seal, thus forming an absolute seal. As long as the pressure difference on both sides is not particularly large, the lubricating oil will not leak. However, for high-speed rotating components, there will be a relatively large relative speed between the stator lip and the rotor surface, and the frictional force of the oil film is not zero. Therefore, during high-speed operation, this oil film will cause power loss. If the speed further increases, the frictional heat generation will cause the temperature to rise, and the oil film may not be able to withstand the too high temperature, resulting in the drying of the oil film. Once the oil film dries up, the lip of the oil seal will come into direct contact with the rotor, and the friction will immediately increase, which will not only cause a sharp increase in power loss, but also cause the lip of the oil seal to wear out and fail in a very short time. In addition, the oil film has a small amount of evaporation. Even if the rotation speed is not high, after a long time, the oil film will dry up and further cause damage to the oil seal. In fact, all contact type dynamic seals face the problems of low rotation speed and short service life.

[0004] For high-speed equipment, if long life and reliability are to be ensured, only non-contact seals can be selected. Whether it is a tooth seal or a labyrinth seal, the non-contact seal only forms a relatively small gap between the rotor and the stator, which can only slow down the leakage speed, but actually cannot ensure absolute sealing. As long as there is a pressure difference on both sides of the seal, there will definitely be a small amount of leakage. After a long time of leakage, lubricating oil must be added. And the leaked oil may accumulate in some places and cause problems after a certain period of time.

[0005] Contact type seals have a short service life and poor reliability; non-contact seals have poor sealing performance and a small amount of leakage. How to ensure long life, reliability, and at the same time ensure sealing performance has become an important issue in this technical field. Summary of the Utility Model

[0006] The technical problem to be solved by the present utility model is to provide an air seal structure for a bearing chamber. The technical solution it adopts is: an air seal structure for a bearing chamber, which includes a main shaft, a bearing and an inner cover plate installed on the main shaft, and a bearing housing surrounding the bearing. Among them, the inner cover plate is fixedly connected to the bearing housing, and a first piston ring and a second piston ring are arranged between the inner cover plate and the main shaft. The characteristic is that: a main air passage is also arranged on the bearing housing, and an inner branch air passage that is communicated with the main air passage and guides between the first piston ring and the second piston ring is arranged on the inner cover plate.

[0007] A further technical feature of the present utility model is:

[0008] The inner branch air passage includes an inner radial air passage and an inclined air passage, and the inclined air passage is communicated with the main air passage.

[0009] A plug is arranged on the inner radial air passage in the outer diameter direction.

[0010] Under the same inventive concept, the present utility model also provides another air seal structure for a bearing chamber. The technical solution it adopts is: an air seal structure for a bearing chamber, which includes a main shaft, a bearing, an outer cover plate, an inner cover plate installed on the main shaft, and a bearing housing surrounding the bearing. Among them, the outer cover plate and the inner cover plate are respectively fixedly connected to the bearing housing, a first piston ring and a second piston ring are arranged between the inner cover plate and the main shaft, a rotor auxiliary part is arranged on the main shaft outside the bearing, and a third piston ring and a fourth piston ring are arranged on the rotor auxiliary part. The characteristic is that: a main air passage is also arranged on the bearing housing, an inner branch air passage that is communicated with the main air passage and guides into the gap between the first piston ring and the second piston ring is arranged on the inner cover plate, and an outer branch air passage that is communicated with the main air passage and guides between the third piston ring and the fourth piston ring is arranged on the outer cover plate.

[0011] The outer branch air passage is an outer radial air passage, and the inner branch air passage includes an inner radial air passage and an inclined air passage, and the inclined air passage is communicated with the main air passage.

[0012] A plug is arranged on the inner radial air passage in the outer diameter direction.

[0013] The beneficial effects of the present utility model are:

[0014] Since the bearing housing is provided with a main air passage, high-pressure air can be input through the main air passage. The inner cover plate is provided with an inner branch air passage that is in communication with the main air passage and guides air between the first piston ring and the second piston ring. In this way, on the lubricant-free side of the non-contact seal of the first piston ring, air with a pressure higher than that on the lubricant side can be provided. When the lubricant attempts to leak through the tiny gap of the non-contact seal to the lubricant-free side, the high-pressure air will block the lubricant, preventing the lubricant from leaking. This ensures that the lubricant is completely leak-free. The application scenario of this solution is that the air pressure in the chamber inside the bearing housing is normal or low, and high-pressure lubricant may leak, so such a seal is required. The outside of the bearing housing does not need to be sealed. For example, if the outside of the bearing housing is a gearbox, gear meshing itself requires lubrication with lubricant, and at this time, we do not need to prevent the lubricant inside the bearing from leaking to the left through a seal. In this case, only the inner seal is needed.

[0015] With the same inventive concept, when the outside of the bearing housing also needs to prevent lubricant leakage, the bearing housing is provided with a main air passage. The inner cover plate is provided with an inner branch air passage that is in communication with the main air passage and guides air into the gap between the first piston ring and the second piston ring. The outer cover plate is also provided with an outer branch air passage that is in communication with the main air passage and guides air into the gap between the third piston ring and the fourth piston ring. In this way, on the lubricant-free sides of the non-contact seals of the first piston ring and the fourth piston ring, air with a pressure higher than that on the lubricant side can be provided. When the lubricant attempts to leak through the tiny gap of the non-contact seal to the lubricant-free side, the high-pressure air will block the lubricant, preventing the lubricant from leaking. This ensures that the lubricant inside and outside the bearing housing is completely leak-free, and the seal is more reliable. Description of the Drawings

[0016] Figure 1 is a structural cross-sectional view of the first embodiment of the present utility model;

[0017] Figure 2 is a structural cross-sectional view of the second embodiment of the present utility model;

[0018] Figure 3 is a structural cross-sectional view of the third embodiment of the present utility model;

[0019] Figure 4 is a structural cross-sectional view of the fourth embodiment of the present utility model. Detailed Description of the Embodiments

[0020] The present utility model will be further described in detail below with reference to the drawings. Embodiment 1

[0021] Refer to Figure 1, An air seal structure for a bearing chamber, which includes a main shaft 1, a bearing 2 mounted on the main shaft, an inner cover plate 3, and a bearing housing 4 arranged around the bearing. The inner cover plate 3 is fixedly connected to the bearing housing 4. A first piston ring 5 and a second piston ring 6 are arranged between the inner cover plate 3 and the main shaft 1. It is characterized in that: A main air passage 7 is also arranged on the bearing housing 4, and an inner branch air passage 8 that is communicated with the main air passage 7 and guides between the first piston ring 5 and the second piston ring 6 is arranged on the inner cover plate 3.

[0022] Since the main air passage 7 is arranged on the bearing housing, high-pressure air can be input through the main air passage 7. The inner cover plate 3 is provided with an inner branch air passage 8 that is communicated with the main air passage 7 and guides between the first piston ring 5 and the second piston ring 6. In this way, on the non-lubricating oil side of the non-contact seal of the first piston ring 5, air with a pressure higher than that on the lubricating oil side can be provided. When the lubricating oil tries to leak to the non-lubricating oil side through the tiny gap of the non-contact seal, the high-pressure air will block the lubricating oil, making the lubricating oil unable to leak. In this way, it is ensured that the lubricating oil is completely leak-free and the seal is more reliable; at the same time, due to the limitation of the first piston ring 5 and the second piston ring 6, the loss of the high-pressure air input through the main air passage 7 is very small. Embodiment Two

[0023] Refer to Figure 2 , The difference in its structure from Embodiment One is that the inner branch air passage 8 in Embodiment One is cast, while the inner branch air passage 8 in this embodiment is machined. In this embodiment, the inner branch air passage 8 includes an inner radial air passage 81 and an inclined air passage 9, and the inclined air passage 9 is communicated with the main air passage 7. A plug 15 is arranged in the outer diameter direction of the inner radial air passage, so that the inner branch air passage 8 is convenient for machining. Embodiment Three

[0024] Refer to Figure 3, A gas seal structure for a bearing chamber, which includes a main shaft 1, a bearing 2 mounted on the main shaft, an outer cover plate 10, an inner cover plate 3, and a bearing housing 4 arranged around the bearing. The outer cover plate 10 and the inner cover plate 3 are respectively fixedly connected to the bearing housing 4. A first piston ring 5 and a second piston ring 6 are arranged between the inner cover plate 3 and the main shaft 1. A rotor auxiliary part 11 is arranged on the main shaft 1 outside the bearing, and a third piston ring 12 and a fourth piston ring 13 are arranged on the rotor auxiliary part. It is characterized in that: a main gas path 7 is also arranged on the bearing housing 4, high-pressure air can be input through the main gas path 7, an inner branch gas path is arranged on the inner cover plate 3 and is communicated with the main gas path 7 and guides to the gap between the first piston ring 5 and the second piston ring 6, and an outer branch gas path is arranged on the outer cover plate 10 and is communicated with the main gas path 7 and guides to the gap between the third piston ring 12 and the fourth piston ring 13. In this embodiment, the outer branch gas path 14 is an outer radial gas path, and the inner branch gas path 8 includes an inner radial gas path 81 and an inclined gas path 9, and the inclined gas path 9 is communicated with the main gas path 7.

[0025] Since a main gas path 7 is arranged on the bearing housing, an inner branch gas path 8 is arranged on the inner cover plate 3 and is communicated with the main gas path 7 and guides to the gap between the first piston ring 5 and the second piston ring 6, and an outer branch gas path 14 is also arranged on the outer cover plate 10 and is communicated with the main gas path 7 and guides to the gap between the third piston ring 12 and the fourth piston ring 13. In this way, on the non-lubricating oil side of the non-contact seals of the first piston ring 5 and the fourth piston ring 13, air with a pressure higher than that on the lubricating oil side can be provided. When the lubricating oil tries to leak to the non-lubricating oil side through the tiny gap of the non-contact seal, the high-pressure air will block the lubricating oil, making the lubricating oil unable to leak. In this way, it is ensured that there is no leakage of lubricating oil on the outside and inside of the bearing chamber, and the seal is more reliable; at the same time, due to the limitation of the first piston ring 5, the second piston ring 6, the third piston ring 12 and the fourth piston ring 13, the loss of the high-pressure air input from the main gas path 7 is very small. Embodiment 4

[0026] Refer to Figure 4 , Its structure is different from that of Embodiment 3 in that the inner branch gas path 8 in Embodiment 3 is cast, while the inner branch gas path 8 in this embodiment is machined. In this embodiment, the inner branch gas path 8 includes an inner radial gas path 81 and an inclined gas path 9, and the inclined gas path 9 is communicated with the main gas path 7. A plug 15 is arranged on the inner radial gas path in the outer diameter direction, so that the inner branch gas path 8 is convenient for machining.

[0027] The technical content and features of the present utility model have been disclosed above. However, it can be understood that those skilled in the art can make various changes and improvements to the above structure under the spirit and creative idea of the present utility model, including combinations of the technical features separately disclosed or claimed here, as well as other combinations that obviously include these features. These variations and / or combinations all fall within the technical field involved in the present utility model and within the protection scope of the claims of the present utility model.

Claims

1. An air seal structure for a bearing chamber, which comprises a main shaft, a bearing and an inner cover plate mounted on the main shaft, and a bearing housing arranged around the bearing, wherein the inner cover plate is fixedly connected with the bearing housing, and a first piston ring and a second piston ring are arranged between the inner cover plate and the main shaft, and is characterized in that: A main air passage is further provided on the bearing housing, and an inner branch air passage that is communicated with the main air passage and guides between the first piston ring and the second piston ring is provided on the inner cover plate.

2. The gas seal structure for the bearing chamber according to claim 1, wherein: The inner branch air passage includes an inner radial air passage and an inclined air passage, wherein the inclined air passage is communicated with the main air passage.

3. The air seal structure for the bearing chamber according to claim 2, wherein: A plug is provided on the inner radial air passage in the outer diameter direction.

4. An air seal structure for a bearing chamber, which comprises a main shaft, a bearing mounted on the main shaft, an outer cover plate, an inner cover plate, and a bearing housing arranged around the bearing, wherein the outer cover plate and the inner cover plate are respectively fixedly connected to the bearing housing, a first piston ring and a second piston ring are arranged between the inner cover plate and the main shaft, a rotor auxiliary is arranged on the main shaft outside the bearing, and a third piston ring and a fourth piston ring are arranged on the rotor auxiliary, and it is characterized in that: A main air passage is further provided on the bearing housing, an inner branch air passage that is communicated with the main air passage and guides into the gap between the first piston ring and the second piston ring is provided on the inner cover plate, and an outer branch air passage that is communicated with the main air passage and guides between the third piston ring and the fourth piston ring is provided on the outer cover plate.

5. The air seal structure for the bearing chamber according to claim 4, characterized in that: The outer branch air passage is an outer radial air passage, and the inner branch air passage includes an inner radial air passage and an inclined air passage, wherein the inclined air passage is communicated with the main air passage.

6. The air seal structure for the bearing chamber according to claim 5, characterized in that: A plug is provided on the inner radial air passage in the outer diameter direction.

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