Oil seal structure capable of eliminating internal pressure influence
By designing an oil seal structure with an oil slinger, multi-stage labyrinth cavity, and inclined oil drain hole in the speed-increasing gearbox, the problem of oil mist leakage was solved, the sealing performance and stability were enhanced, and the cost was reduced.
Patent Information
- Application Number
- CN202520670173.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-09
- Publication Date
- 2026-02-24
- Estimated Expiration
- 2035-04-09
AI Technical Summary
In the existing technology, the labyrinth oil seal structure of the speed-increasing gearbox is prone to oil mist leakage under the combined influence of the internal pressure of the gearbox and the air extraction effect of the coupling, which is especially obvious in high-pressure blowers.
An oil seal structure to eliminate the influence of internal pressure was designed, including adding an oil slinger groove and a multi-stage labyrinth cavity structure on the input shaft, combined with an inclined oil drain hole and an oil guide pipe. The oil discharge effect is enhanced by centrifugal oil slinging and labyrinth effect, and the negative pressure effect during the operation of the coupling is counteracted by the balance cavity.
It effectively prevents oil mist leakage, improves sealing performance and stability, reduces costs, and achieves a highly efficient sealing effect.
Smart Images
Figure CN223938609U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of gearbox sealing technology, and in particular to an oil seal structure that eliminates the influence of internal pressure. Background Technology
[0002] In existing technologies, single-stage high-speed centrifugal fans employing speed-increasing gearboxes generally utilize labyrinth-type oil seal structures at their input ends. However, under the combined influence of internal gearbox pressure and coupling suction effect, oil mist leakage frequently occurs at the labyrinth seal, a problem particularly pronounced in high-pressure fans. Summary of the Invention
[0003] Therefore, the technical problem to be solved by this utility model is to overcome the problem of oil mist leakage inside the gearbox caused by the combined effects of pressure inside the gearbox and air extraction effect of the coupling through the labyrinth seal in the prior art.
[0004] To solve the above-mentioned technical problems, this utility model provides an oil seal structure that eliminates the influence of internal pressure, comprising:
[0005] A gearbox body and an end cover connected thereto, wherein a bearing is provided inside the gearbox body;
[0006] An input shaft supported by the bearing is provided with a gear. The input shaft includes a first shaft section and a second shaft section with different diameters. An oil slinger ring is provided on the second shaft section. The first shaft section is connected to a coupling.
[0007] A sealing element is connected to the end cap and sleeved on the second section of the shaft. The sealing element is provided with an oil return hole, an oil drain hole, a balance chamber, and a balance hole. The balance chamber is connected to the atmosphere through the balance hole.
[0008] An auxiliary cavity is formed between the gearbox body, the seal and the end cover, and an oil slinger gap is formed between the axial end face of the seal and the oil slinger ring, and the oil slinger gap is connected to the auxiliary cavity;
[0009] A multi-level labyrinth cavity structure is formed between the inner hole of the seal and the shaft section. The multi-level labyrinth cavity structure includes multiple labyrinth cavities. The oil return holes extend one-to-one into each of the labyrinth cavities. Each oil return hole communicates with the oil drain hole. The end of the oil drain hole away from the oil return hole is inclined towards the auxiliary cavity. The oil drain hole is connected to an oil guide pipe, which is connected to the oil tank.
[0010] In one embodiment of this utility model, the oil-throwing gap is a conical structure and gradually expands in the direction away from the multi-level labyrinth cavity structure.
[0011] In one embodiment of this utility model, a plurality of oil-throwing grooves are distributed along the axial direction of the second shaft section, and a plurality of sealing teeth extending toward the second shaft section are provided along the axial direction of the inner hole of the seal. Each oil-throwing groove and the two adjacent sealing teeth on both sides form the labyrinth cavity.
[0012] In one embodiment of this utility model, the width of the oil-throwing gap is 0.5~1mm.
[0013] In one embodiment of this utility model, the multi-level labyrinth cavity structure includes 4 to 7 labyrinth cavities.
[0014] In one embodiment of this utility model, the width of the labyrinth cavity is not less than 6 mm, and the depth is not less than 1.5 times the width.
[0015] In one embodiment of this utility model, the cross-sectional area of the balance cavity is not less than 1.5 times the area of a single labyrinth cavity.
[0016] In one embodiment of this utility model, a plurality of the balance holes extend radially into the balance cavity, and the total ventilation area of the plurality of balance holes is not less than 5 times the gap area between the sealing tooth and the input shaft.
[0017] The above-mentioned technical solution of this utility model has the following advantages compared with the prior art:
[0018] The oil seal structure described in this utility model for eliminating the influence of internal pressure is simple in structure and low in cost. By adding an oil slinger groove on the input shaft, the oil discharge effect is effectively enhanced. The oil discharge hole is set at an angle, so that the pressurized oil flows smoothly back to below the oil level in the oil tank, avoiding oil mist leakage from the gearbox through the oil discharge hole under the action of internal pressure.
[0019] This invention optimizes the structure and axial dimensions of the oil slinger ring and seal on the input shaft, enhancing the centrifugal oil slinger effect and improving sealing performance from the source of leakage.
[0020] This invention effectively counteracts the adverse effects of the coupling on the sealing area during operation by setting up a pressure balance chamber, thereby further improving the stability and reliability of the overall seal. Attached Figure Description
[0021] To make the content of this utility model easier to understand, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings.
[0022] Figure 1 This is a schematic diagram of the oil seal structure of this utility model for eliminating the influence of internal pressure.
[0023] Explanation of reference numerals on the accompanying drawings:
[0024] 1. Coupling; 2. Input shaft; 21. Shaft section 1; 22. Shaft section 2; 23. Oil slinger groove; 24. Oil slinger ring; 25. Gear; 3. Seal; 30. Balance chamber; 31. Sealing tooth; 32. Balance hole; 33. Labyrinth chamber; 34. Oil return hole; 35. Oil drain hole; 4. Second screw; 5. First screw; 6. End cover; 7. Bearing; 8. Gearbox body; 9. Auxiliary chamber; 10. Oil guide pipe; 130. Negative pressure zone; 230. Oil slinger gap. Detailed Implementation
[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments are not intended to limit the present invention.
[0026] In this utility model, when directions (up, down, left, right, front, and back) are described, it is only for the convenience of describing the technical solution of this utility model, and does not indicate or imply that the technical features referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this utility model.
[0027] In this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," "exceeding," etc. are understood to exclude the stated number; "above," "below," "within," etc. are understood to include the stated number. In the description of this utility model, if "first" or "second" is used, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the order of the indicated technical features.
[0028] In this utility model, unless otherwise explicitly defined, terms such as "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a direct connection or an indirect connection through an intermediate medium; a fixed connection, a detachable connection, or an integrally formed connection; a mechanical connection, an electrical connection, or a connection capable of mutual communication; or the internal connection of two components or the interaction between two components. Those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model based on the specific content of the technical solution.
[0029] Reference Figure 1 As shown, the present invention provides an oil seal structure for eliminating the influence of internal pressure, comprising:
[0030] The gearbox body 8 and the end cover 6 connected to it by the first screw 5, wherein the gearbox body 8 is provided with a bearing 7;
[0031] The input shaft 2 is supported by the bearing 7. The input shaft 2 is equipped with a gear 25. The input shaft 2 includes a first shaft section 21 and a second shaft section 22 with different diameters. An oil slinger ring 24 is provided on the second shaft section 22. The first shaft section 21 is connected to the coupling 1.
[0032] The sealing element 3 is connected to the end cap 6 by the second screw 4 and is sleeved on the second section 22 of the shaft. The sealing element 3 is provided with an oil return hole 34, an oil drain hole 35, a balance chamber 30 and a balance hole 32. The balance chamber 30 is connected to the atmosphere through the balance hole 32.
[0033] An auxiliary cavity 9 is formed between the gearbox body 8, the seal 3 and the end cover 6. An oil slinger gap 230 is formed between the axial end face of the seal 3 and the oil slinger ring 24. The oil slinger gap 230 is connected to the auxiliary cavity 9.
[0034] A multi-level labyrinth cavity structure is formed between the inner hole of the seal 3 and the shaft section 22. The multi-level labyrinth cavity structure includes multiple labyrinth cavities 33. The oil return holes 34 extend one-to-one into each of the labyrinth cavities 33. Each of the oil return holes 34 communicates with the oil drain hole 35. The end of the oil drain hole 35 away from the oil return hole 34 is inclined towards the auxiliary cavity 9. The oil drain hole 35 is connected to an oil guide pipe 10, which is connected to the oil tank (below the oil level).
[0035] By adding an oil slinger 23 to the input shaft 2, the oil discharge effect is effectively enhanced; the oil discharge hole 35 is set at an angle, so that the pressure oil flows smoothly back to below the oil level in the oil tank, and prevents oil mist from leaking outward through the oil discharge hole 35 under internal pressure.
[0036] In one embodiment, the oil-throwing gap 230 is a conical structure that gradually expands in a direction away from the multi-level labyrinth cavity structure.
[0037] In one embodiment, a plurality of oil-slinging grooves 23 are distributed along the axial direction of the second shaft section 22, and a plurality of sealing teeth 31 extending toward the second shaft section 22 are arranged along the axial direction of the inner hole of the seal 3. Each oil-slinging groove 23 and the two adjacent sealing teeth 31 on both sides form the labyrinth cavity 33.
[0038] In one embodiment, the width x of the oil-throwing gap 230 is between 0.5 and 1 mm.
[0039] In one embodiment, the multi-level labyrinth structure includes 4 to 7 labyrinth cavities 33. Each labyrinth cavity 33 has an oil return hole 34 at its bottom, which is connected to an oil drain hole 35.
[0040] In one embodiment, the width a of the labyrinth cavity 33 is not less than 6 mm, and the depth h is not less than 1.5 times the width.
[0041] In one embodiment, the cross-sectional area of the balance cavity 30 is not less than 1.5 times the area of a single labyrinth cavity 33; a plurality of balance holes 32 extend radially into the balance cavity 30, and the total ventilation area of the plurality of balance holes 32 is not less than 5 times the gap area between the sealing tooth 31 and the input shaft 2, so as to ensure that the balance cavity 30 does not generate negative pressure.
[0042] The sealing principle is as follows: Pressurized oil enters the auxiliary cavity 9 through the gap between the bearing 7 and the input shaft 2. Most of the oil returns to the inner cavity of the gearbox 8 through the bottom through hole. A small portion of the oil enters the oil-throwing gap 230 and attempts to enter the multi-stage labyrinth structure through the gap between the sealing teeth 31 and the input shaft 2. Due to centrifugal force, most of the oil entering the oil-throwing gap 230 is "thrown out" into the auxiliary cavity 9 and finally returns to the inner cavity of the gearbox 8. A very small amount of oil entering the first-stage labyrinth cavity 33 is mostly discharged into the oil drain hole 35 through the bottom oil return hole 34 under the action of the oil-throwing groove 23, and then discharged into the oil tank (below the oil level) through the oil guide pipe 10. As can be seen from the labyrinth sealing principle, when oil and gas pass through the sealing teeth 31, the kinetic energy increases and the pressure decreases. The heat energy of the oil entering the labyrinth cavity 33 increases, but the pressure hardly recovers. By analogy, the oil pressure in the labyrinth cavity 33 decreases step by step until the pressure of the last stage reaches equilibrium with the pressure (atmospheric pressure) of the balance cavity 30, thereby achieving the purpose of sealing.
[0043] Due to centrifugal force, a negative pressure zone 130 is generated when the distance between the coupling 1 and the seal 3 is small. The balance chamber 30 is designed to eliminate the adverse effects of negative pressure on the seal. When negative pressure is generated in the negative pressure zone 130, air from the balance chamber 30 enters the negative pressure zone 130, while atmospheric air is introduced into the balance chamber 30 through the balance hole 32, ensuring that the pressure inside the balance chamber 30 is always equal to atmospheric pressure. This ensures the reliability of the labyrinth seal.
[0044] In addition, the oil return hole 34 at the bottom of the labyrinth cavity 33 is connected to the inclined oil drain hole 35. The oil entering the oil drain hole 35 is discharged into the oil tank (below the oil level) through the oil guide pipe 10. This avoids the problem of oil mist in the gearbox 8 leaking outward through the oil drain hole 35 under the action of internal pressure.
[0045] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solution of this utility model and not to limit it. Although this utility model has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of this utility model without departing from the spirit and scope of the technical solution of this utility model, and all such modifications and substitutions should be covered within the scope of the claims of this utility model.
Claims
1. An oil seal structure for eliminating the influence of internal pressure, characterized in that, include: Gearbox body (8) and end cap (6) connected thereto, wherein a bearing (7) is provided inside the gearbox body (8); The input shaft (2) is supported by the bearing (7), and a gear (25) is provided on the input shaft (2). The input shaft (2) includes a shaft section (21) and a shaft section (22) with different diameters. An oil slinger ring (24) is provided on the shaft section (22). The shaft section (21) is connected to the coupling (1). A sealing element (3) is connected to the end cap (6) and sleeved on the second section (22) of the shaft. The sealing element (3) is provided with an oil return hole (34), an oil drain hole (35), a balance chamber (30) and a balance hole (32). The balance chamber (30) is connected to the atmosphere through the balance hole (32). An auxiliary cavity (9) is formed between the gearbox body (8), the seal (3) and the end cover (6). An oil slinger gap (230) is formed between the axial end face of the seal (3) and the oil slinger ring (24). The oil slinger gap (230) is connected to the auxiliary cavity (9). A multi-level labyrinth cavity structure is formed between the inner hole of the seal (3) and the shaft section (22). The multi-level labyrinth cavity structure includes multiple labyrinth cavities (33). The oil return holes (34) extend one-to-one into each of the labyrinth cavities (33). Each of the oil return holes (34) communicates with the oil drain hole (35). The end of the oil drain hole (35) away from the oil return hole (34) is inclined towards the auxiliary cavity (9). The oil drain hole (35) is connected to an oil guide pipe (10). The oil guide pipe (10) is connected to the oil tank.
2. The oil seal structure for eliminating the influence of internal pressure according to claim 1, characterized in that, The oil-throwing gap (230) has a conical structure and gradually expands in the direction away from the multi-level labyrinth cavity structure.
3. An oil seal structure for eliminating the influence of internal pressure according to claim 1 or 2, characterized in that, A plurality of oil-slinging grooves (23) are distributed along the axial direction of the second shaft section (22), and a plurality of sealing teeth (31) extending toward the second shaft section (22) are provided along the axial direction of the inner hole of the sealing element (3). Each oil-slinging groove (23) forms a labyrinth cavity (33) between itself and two adjacent sealing teeth (31) on both sides.
4. The oil seal structure for eliminating the influence of internal pressure according to claim 1, characterized in that, The width of the oil slinger gap (230) is 0.5~1mm.
5. The oil seal structure for eliminating the influence of internal pressure according to claim 1, characterized in that, The multi-level labyrinth structure includes 4 to 7 labyrinth cavities (33).
6. The oil seal structure for eliminating the influence of internal pressure according to claim 1, characterized in that, The width of the labyrinth cavity (33) is not less than 6 mm, and the depth is not less than 1.5 times the width.
7. The oil seal structure for eliminating the influence of internal pressure according to claim 1, characterized in that, The cross-sectional area of the balance cavity (30) is not less than 1.5 times the area of a single labyrinth cavity (33).
8. The oil seal structure for eliminating the influence of internal pressure according to claim 3, characterized in that, A plurality of the balance holes (32) extend radially into the balance cavity (30), and the total ventilation area of the plurality of balance holes (32) is not less than 5 times the gap area between the sealing tooth (31) and the input shaft (2).