Oil seal structure of input end of step-up gear box
By designing a multi-stage labyrinth cavity structure, an oil slinger, and a pressure balance chamber at the input end of the speed-increasing gearbox, the problem of oil mist leakage was solved, achieving efficient sealing and reducing costs.
Patent Information
- Application Number
- CN202520655569.5
- 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 seal structure at the input end of the speed-increasing gearbox cannot effectively isolate the problem of oil mist leakage from the inside of the gearbox, which is especially serious under the operating conditions of high-pressure blowers.
An oil seal structure for the input end of a speed-increasing gearbox was designed, including a multi-stage labyrinth cavity structure, an oil slinger groove, an oil slinger ring, and a pressure balance cavity. The sealing effect is achieved by combining the oil slinger groove and the labyrinth cavity with negative pressure and atmospheric balance.
It improves sealing reliability, reduces oil mist leakage, has a simple structure and low cost, and enhances the sealing effect.
Smart Images
Figure CN223938608U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of gear sealing technology, and in particular to an oil seal structure at the input end of a speed-increasing gearbox. Background Technology
[0002] In existing technologies, single-stage high-speed centrifugal fans driven by speed-increasing gearboxes typically employ a labyrinth oil seal structure at the input end. However, due to the pressure inside the gearbox and the suction effect that easily occurs during coupling operation, the labyrinth seal structure often fails to achieve effective isolation under these dual effects. This leads to frequent leakage of oil mist from inside the gearbox through the labyrinth seal gaps, a problem that is particularly severe under high-pressure fan operating conditions. Summary of the Invention
[0003] Therefore, the technical problem to be solved by this utility model is to overcome the problem in the prior art that oil mist inside the gearbox is prone to leakage to the outside through the labyrinth seal gap.
[0004] To solve the above-mentioned technical problems, this utility model provides an oil seal structure for the input end of a speed-increasing gearbox, including a connected gearbox body and an end cover, wherein a bearing is disposed inside the gearbox body; and further includes:
[0005] The drive assembly includes an input shaft supported by the bearing and a gear and coupling connected to the input shaft. 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 the coupling, and a plurality of oil slinger grooves are distributed along the axial direction of the second shaft section.
[0006] A sealing element, connected to the end cap and sleeved on the second section of the shaft, forms an auxiliary cavity between the gearbox body, the sealing element, and the end cap. Several sealing teeth extending towards the second section of the shaft are arranged axially along the inner hole of the sealing element. Each oil slinger groove forms a labyrinth cavity between itself and two adjacent sealing teeth on its sides. All the labyrinth cavities constitute a multi-level labyrinth cavity structure. The sealing element also has an oil return hole, an oil drain hole, a balance cavity, and a balance hole. The oil return hole extends one-to-one into each of the labyrinth cavities. Each oil drain hole communicates with one or more of the oil return holes. The balance cavity is connected to the atmosphere through the balance hole.
[0007] Wherein, an oil-throwing gap is formed between the axial end face of the seal and the oil-throwing ring, and both the oil-throwing gap and the oil drain hole are connected to the auxiliary cavity;
[0008] The pressurized oil can enter the multi-stage labyrinth cavity structure through the oil slinger gap; the negative pressure can introduce air from the balance cavity into the negative pressure zone, and at the same time, the atmospheric pressure can be introduced into the balance cavity through the balance hole, so that the pressure in the balance cavity is equal to the atmospheric pressure.
[0009] In one embodiment of this utility model, the multi-level labyrinth cavity structure includes 4 to 7 labyrinth cavities.
[0010] 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.
[0011] In one embodiment of this utility model, the oil return hole extends radially and communicates with the oil drain hole, and the end of the oil drain hole away from the oil return hole is inclined toward the auxiliary cavity.
[0012] In one embodiment of this utility model, at least four of the oil drain holes are respectively connected to a different oil return hole.
[0013] 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.
[0014] 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.
[0015] In one embodiment of this utility model, the width of the oil-throwing gap is 0.5~1mm.
[0016] The above-mentioned technical solution of this utility model has the following advantages compared with the prior art:
[0017] The oil seal structure at the input end of the speed-increasing gearbox described in this utility model is simple and reasonable in structure, with almost no increase in cost and improved sealing reliability.
[0018] This invention increases the size of the labyrinth and adds an oil-slinging groove on the shaft. The oil drain hole is designed as an inclined hole to facilitate oil drainage, and the oil drain hole of each labyrinth cavity is set separately so that they do not interfere with each other.
[0019] This invention enhances the oil-throwing effect by rationally designing the axial dimension between the oil-throwing ring and the seal on the input shaft, thereby improving the sealing effect from the point of leakage initiation.
[0020] This invention eliminates the adverse effects of the coupling on the seal by setting up a pressure balance chamber. 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 at the input end of the speed-increasing gearbox of this utility model.
[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 teeth; 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; 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 discloses an oil seal structure for the input end of a speed-increasing gearbox, comprising a gearbox body 8 and an end cover 6 connected (by a first screw 5), wherein a bearing 7 is disposed inside the gearbox body 8; and further comprising:
[0030] The drive assembly includes an input shaft 2 supported by the bearing 7, a gear 25 connected to the input shaft 2, and a coupling 1. 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, and a plurality of oil slinger grooves 23 are distributed along the axial direction of the second shaft section 22.
[0031] A sealing element 3 is connected to the end cap 6 (via a second screw 4) and sleeved on the second shaft section 22. An auxiliary cavity 9 is formed between the gearbox body 8, the sealing element 3, and the end cap 6. Several sealing teeth 31 extending towards the second shaft section 22 are arranged along the axial direction of the inner hole of the sealing element 3. Each oil slinger groove 23 forms a labyrinth cavity 33 between itself and two adjacent sealing teeth 31 on both sides. All the labyrinth cavities 33 constitute a multi-level labyrinth cavity structure. The sealing element 3 is also provided with an oil return hole 34, an oil drain hole 35, a balance cavity 30, and a balance hole 32. The oil return holes 34 extend one-to-one into each of the labyrinth cavities 33. Each oil drain hole 35 communicates with one or more of the oil return holes 34. The balance cavity 30 is connected to the atmosphere through the balance hole 32.
[0032] Wherein, an oil-throwing gap 230 is formed between the axial end face of the sealing member 3 and the oil-throwing ring 24, and the oil-throwing gap 230 and the oil drain hole 35 are both connected to the auxiliary cavity 9;
[0033] The pressurized oil can enter the multi-stage labyrinth cavity structure through the oil slinger gap 230; the negative pressure can introduce the air in the balance cavity 30 into the negative pressure zone 130, and at the same time, the atmospheric air can be introduced into the balance cavity 30 through the balance hole 32, so that the pressure in the balance cavity 30 is equal to the atmospheric pressure.
[0034] In one embodiment, the multi-level labyrinth structure includes 4 to 7 labyrinth cavities 33. Each labyrinth cavity 33 has a width a ≥ 6 mm and a depth h ≥ 1.5a mm.
[0035] In one embodiment, the oil return hole 34 extends radially and communicates with the oil drain hole 35, and the end of the oil drain hole 35 away from the oil return hole 34 is inclined toward the auxiliary cavity 9, thereby facilitating oil drainage.
[0036] In one embodiment, at least four of the oil drain holes 35 are respectively connected to a different oil return hole 34, which significantly improves the oil discharge efficiency.
[0037] In one embodiment, the cross-sectional area of the balancing cavity 30 is not less than 1.5 times the area of a single labyrinth cavity 33, to ensure that the balancing cavity 30 does not generate negative pressure.
[0038] In one embodiment, 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.
[0039] In one embodiment, the width x of the oil-throwing gap 230 is 0.5~1mm. By reasonably setting the axial dimension between the oil-throwing ring 24 and the seal 3, the oil-throwing effect is enhanced, and the sealing effect is improved from the leakage initiation point.
[0040] The sealing principle of this invention 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 through hole at the bottom of the auxiliary cavity 9. At the same time, 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. However, under the action of centrifugal force, most of the oil entering the oil-throwing gap 230 is "thrown out" and enters the auxiliary cavity 9, eventually returning to the inner cavity of the gearbox 8. The very small amount of oil entering the first-stage labyrinth cavity 33 is mostly discharged from the labyrinth cavity 33 through the bottom oil return hole 34 and the oil drain hole 35 under the action of the oil-throwing groove 23. 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 thermal 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.
[0041] Furthermore, 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.
[0042] Furthermore, since at least four of the drain holes 35 are connected to a different return hole 34, the drain speed can be accelerated, and the leakage can be reduced step by step along the labyrinth seal. When the pressure of the last stage is balanced with the atmospheric pressure, the leakage rate is close to zero.
[0043] 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 the input end of a speed-increasing gearbox, comprising a connected gearbox body (8) and an end cover (6), wherein a bearing (7) is disposed within the gearbox body (8); characterized in that, Also includes: The drive assembly includes an input shaft (2) supported by the bearing (7) and a gear (25) and a coupling (1) connected to the input shaft (2). 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), and a plurality of oil slinger grooves (23) are distributed along the axial direction of the second shaft section (22). A sealing element (3) is connected to the end cover (6) and sleeved on the second section of the shaft (22). An auxiliary cavity (9) is formed between the gearbox body (8), the sealing element (3), and the end cover (6). Several sealing teeth (31) extending towards the second section of the shaft (22) are arranged along the axial direction of the inner hole of the sealing element (3). Each oil slinger groove (23) forms a labyrinth cavity (33) between itself and two adjacent sealing teeth (31) on both sides. All the labyrinth cavities (33) constitute a multi-level labyrinth cavity structure. The sealing element (3) is also provided with an oil return hole (34), an oil drain hole (35), a balance cavity (30), and a balance hole (32). The oil return hole (34) extends one-to-one into each of the labyrinth cavities (33). Each oil drain hole (35) is connected to one or more of the oil return holes (34). The balance cavity (30) is connected to the atmosphere through the balance hole (32). Wherein, an oil-throwing gap (230) is formed between the axial end face of the sealing element (3) and the oil-throwing ring (24), and the oil-throwing gap (230) and the oil drain hole (35) are both connected to the auxiliary cavity (9); The pressurized oil can enter the multi-level labyrinth cavity structure through the oil slinger gap (230); the air in the balance cavity (30) can be introduced into the negative pressure zone (130) through the negative pressure action, and the atmosphere can be introduced into the balance cavity (30) through the balance hole (32) so that the pressure in the balance cavity (30) is equal to the atmospheric pressure.
2. The oil seal structure at the input end of a speed-increasing gearbox according to claim 1, characterized in that, The multi-level labyrinth structure includes 4 to 7 labyrinth cavities (33).
3. The oil seal structure at the input end of a speed-increasing gearbox 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.
4. The oil seal structure at the input end of a speed-increasing gearbox according to claim 1, characterized in that, The return oil hole (34) extends radially and is connected to the drain oil hole (35). The end of the drain oil hole (35) away from the return oil hole (34) is inclined toward the auxiliary cavity (9).
5. The oil seal structure at the input end of a speed-increasing gearbox according to claim 1, characterized in that, At least four of the oil drain holes (35) are connected to a different oil return hole (34).
6. The oil seal structure at the input end of a speed-increasing gearbox 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).
7. The oil seal structure at the input end of a speed-increasing gearbox according to claim 1, 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).
8. The oil seal structure at the input end of a speed-increasing gearbox according to claim 1, characterized in that, The width of the oil slinger gap (230) is 0.5~1mm.