Double-sealing structure for input dry well of speed reducer
By setting a double-seal structure and lubrication system on the input shaft of the reducer, the problems of easy wear and high-temperature vaporization of single-layer oil seals are solved, achieving a highly reliable and stable sealing effect and extending the service life of the reducer.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ZHEJIANG TONGLI HEAVY GEAR
- Filing Date
- 2025-06-03
- Publication Date
- 2026-04-17
AI Technical Summary
The existing single-layer skeleton oil seal of the reducer is prone to wear and aging, which leads to seal failure and lubricating oil leakage. In addition, the magnetic seal structure is complex and has high maintenance costs. Input shaft vibration causes changes in the sealing gap, which exacerbates the risk of leakage. At high temperatures, the lubricating oil vaporizes, increasing the air pressure and damaging the seal.
The system employs a double-sealed structure, including a bearing chamber and a cover on the inlet flange, with first and second skeleton oil seals installed respectively. The first and second tapered roller bearings are mounted back-to-back, and lubrication and venting are achieved through an oil injection hole and a vent hole. An oil retainer ring is used to prevent the lubricating oil from mixing with the grease.
It achieves double sealing protection, improves sealing reliability, reduces the risk of bearing movement, extends the service life of the reducer, ensures stable grease performance, and prevents leakage and high-temperature damage.
Smart Images
Figure CN224135143U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of speed reducers, specifically to a double-sealed structure for the input dry well of a speed reducer. Background Technology
[0002] A speed reducer is an independent component consisting of gears enclosed in a rigid housing. It is commonly used as a speed reduction transmission device between a prime mover and a driven machine. It plays a role in matching speeds and transmitting torque between the prime mover and the driven machine or actuator, and its applications are extremely widespread in modern machinery.
[0003] Chinese utility model patent publication number "CN219911693U" discloses a dry well sealing structure for a speed reducer, including an output shaft and an output gear, a dry well cover, a bearing seat, and a through cover arranged coaxially on the output shaft within the speed reducer housing. The output gear is fixedly connected to the output shaft circumferentially, and a bearing is coaxially provided between the bearing seat and the output shaft to form a rotatable connection. The through cover is detachably fixedly connected to the speed reducer housing and is sealed with an oil seal between it and the output shaft. An annular groove is provided on the side of the output gear near the dry well cover. The dry well cover is fitted onto the output shaft with a gap and one end is fixedly connected to the bearing seat, while the other end extends into the annular groove.
[0004] However, the aforementioned dry well sealing structure for the reducer still has the following drawbacks:
[0005] First, single-layer skeleton oil seals are prone to failure due to wear and aging after long-term operation, leading to lubricating oil leakage or intrusion of external dust and moisture, which affects the life of the reducer. At the same time, magnetic seals have a complex structure, high maintenance costs, and it is difficult to quickly detect the fault point when the seal fails, resulting in high maintenance costs.
[0006] Secondly, vibrations are likely to occur during operation of the input shaft and the equipment, which can lead to changes in the sealing gap and increase the risk of leakage. Furthermore, when the reducer is running outdoors or continuously, the temperature will rise, causing the internal lubricating oil to vaporize and expand, increasing the internal air pressure, which can damage the oil seal or connection of the reducer.
[0007] Therefore, it is necessary to improve upon the aforementioned shortcomings. Utility Model Content
[0008] The purpose of this utility model is to provide a simple and highly reliable double-seal structure for the input dry well of a reducer. This structure isolates the leaking medium through a dry well design, while simultaneously achieving double-seal protection and extending the service life of the reducer, thus solving the above-mentioned problems existing in the prior art.
[0009] To achieve the above objectives, the technical solution adopted by this utility model is as follows: a double-sealed structure for the input shaft of a reducer, comprising a housing, an input shaft, and an input gear. The input gear is located inside the housing and is connected to the input shaft via a key. An input flange is fitted onto the input shaft on the housing. The input flange has a bearing chamber. The input shaft has a first tapered roller bearing and a second tapered roller bearing arranged opposite each other inside the bearing chamber. An oil seal step is provided on the input shaft near one end of the housing. A first skeleton oil seal is provided on the oil seal step. The flange chamber of the input shaft is covered by a cover, and a second skeleton oil seal is fixed on the cover.
[0010] By adopting the above technical solution: the housing and input flange are connected by bolts, the input gear is installed in the housing via a flat key at the end of the input shaft, and the first skeleton oil seal on the oil seal step can isolate the bearing chamber and the inner cavity of the housing, preventing the grease in the bearing chamber and the lubricating oil in the inner cavity of the housing from interpenetrating. Simultaneously, a transparent cover is installed at the end of the bearing chamber of the input flange, and a second skeleton oil seal is added to the transparent cover. This allows observation of the lubricating grease in the bearing chamber and the condition of the first and second tapered roller bearings, while also achieving the function of isolating leaking media and providing dual protection, significantly improving the reliability of the seal. Furthermore, the first and second tapered roller bearings are mounted back-to-back on the input shaft, capable of simultaneously bearing the radial and axial loads of the input shaft, improving the load capacity and stability of the input shaft during operation.
[0011] The aforementioned double-seal structure of the input dry well of the reducer can be further configured as follows: a mounting convex ring is provided in the flange chamber; one end of the first tapered roller bearing abuts against the end face of the oil seal step and the other end abuts against the end face of the mounting convex ring; the second tapered roller bearing abuts against the end face of the mounting convex ring relative to one end face of the first tapered roller bearing; a round nut is provided at the second tapered roller bearing on the input rod to prevent axial movement of the second tapered roller bearing; and a locking washer is also provided between the round nut and the second tapered roller bearing.
[0012] By adopting the above technical solution: the first tapered roller bearing is first installed on the input rod and contacts the end face of the oil seal step. Then, the input shaft passes through the bearing housing, so that the other end face of the first tapered roller bearing abuts against the end face of the mounting cam, thereby axially fixing the first tapered roller bearing. Then, the second tapered roller bearing abuts against the other end face of the mounting cam. The round nut is fixed on the input shaft by threaded rotation, and the preload is used to press the second tapered roller bearing, effectively preventing the second tapered roller bearing from shifting axially. The retaining washer further improves the retaining ability of the round nut on the second tapered roller bearing. Furthermore, the first and second tapered roller bearings, in conjunction with the mounting cam, can withstand greater axial forces and are more adaptable to working conditions with frequent impacts or heavy loads.
[0013] The aforementioned dry well double-seal structure of the reducer can be further configured such that: a lubrication chamber is formed between the first tapered roller bearing, the second tapered roller bearing, and the mounting ring; an oil injection hole communicating with the lubrication chamber is provided on the side wall of the input flange; and a grease nipple is installed in the oil injection hole.
[0014] By adopting the above technical solution: the inner rings of the first and second tapered roller bearings contact the input shaft, and the outer rings contact the inner wall of the bearing chamber. A lubrication chamber is formed between the first and second tapered roller bearings and the mounting ring. Since the bearings need to move the grease in the bearing chamber when they rotate, the grease between the first and second tapered roller bearings will be rotated to the outside of the lubrication chamber, making it difficult to ensure that the first and second tapered roller bearings receive continuous lubrication. Therefore, by connecting the oil injection hole to the bearing chamber on the side of the input flange and setting a grease nipple at the end of the oil injection hole, the grease can easily enter the lubrication chamber through the oil injection hole, thereby effectively lubricating the first and second tapered roller bearings, delaying bearing fatigue damage and significantly increasing bearing service life.
[0015] The aforementioned reducer input dry well double sealing structure can be further configured such that: the input flange also has a vent hole penetrating the side wall, and the vent hole is equipped with a vent cap.
[0016] By adopting the above technical solution: when the reducer is running continuously at high temperature or high intensity, the internal temperature of the reducer will rise, causing the lubricating oil and grease inside the reducer and input flange to vaporize, and the internal air pressure will continue to increase, which can easily lead to damage to the oil seal or connection. Therefore, by opening a vent hole through the side wall of the input flange, the vent cap on the vent hole can open when the internal air pressure of the reducer reaches the threshold, thereby venting and depressurizing the reducer, preventing the internal air pressure from being too high, and thus protecting the sealing structure of the reducer.
[0017] The aforementioned reducer input dry well double sealing structure can be further configured as follows: the input shaft is provided with an oil baffle ring inside the housing, one end face of the oil baffle ring abuts against the inner wall of the housing, and the other end is snapped with an elastic retaining ring.
[0018] By adopting the above technical solution: the oil retainer ring is limited by the elastic retainer ring and the inner wall of the oil tank. Since the lubricants in the reducer cavity and the bearing chamber of the input flange are different, the reducer cavity usually uses lubricating oil, while the bearing chamber usually uses lubricating grease. The mixing of the two will lead to a decrease in the lubricating ability of the lubricating oil and the lubricating grease. The oil retainer ring can not only cover the gap between the first skeleton oil seal and the input shaft, but also throw the lubricating oil back into the oil sump in the housing or change the direction of the lubricating oil return when the input shaft rotates, thus preventing the lubricating oil from seeping into the bearing chamber through the gap and mixing with the lubricating grease. This ensures the stability of the lubricating grease performance and further improves the sealing ability of the first skeleton oil seal for the reducer cavity and the bearing chamber.
[0019] The beneficial effects of this utility model are as follows:
[0020] First, by setting a bearing chamber on the input flange and setting a first skeleton oil seal and a second skeleton oil seal at both ends of the bearing chamber, a double seal can be achieved between the inner cavity of the gearbox and the bearing chamber, and between the bearing chamber and the outside of the reducer. This can prevent the mixing of lubricating oil and grease, ensuring lubrication performance, and also prevent the leakage of lubricating oil or grease, thereby improving the sealing performance of the first skeleton oil seal and the second skeleton oil seal structure.
[0021] Secondly, the first and second tapered roller bearings are installed back-to-back in the bearing housing. The first tapered roller bearing is limited by an oil seal step and a mounting cam, while the second tapered roller bearing is limited by a mounting cam and a round nut. This significantly reduces the risk of axial movement of the input shaft, the first tapered roller bearing, and the second tapered roller bearing, improving the stability of the reducer during operation. Furthermore, a lubrication chamber is formed between the first and second tapered roller bearings, and the oil injection hole connects to the lubrication chamber. Grease can be quickly replenished to the lubrication chamber through the grease nipple at the end of the oil injection hole, ensuring smooth rotation of the first and second tapered roller bearings, reducing fatigue damage caused by friction, and increasing service life.
[0022] Third, an oil baffle ring is installed at the connection between the first skeleton oil seal and the oil tank. This baffle ring covers the gap between the first skeleton oil seal and the bearing housing, preventing lubricating oil from seeping into the gap and mixing with the grease. The oil baffle ring is snapped onto the input shaft by an elastic retainer ring and can rotate synchronously with the input shaft. The lubricating oil splashed by the rotation of the gears inside the housing is blocked by the rotating oil baffle ring and thrown back into the oil sump inside the housing by the centrifugal force generated by the rotation of the oil baffle ring. This prevents a large amount of lubricating oil from accumulating at the connection gap between the first skeleton oil seal and the bearing housing, ensuring the separation performance of the first skeleton oil seal between the inner cavity of the housing and the bearing housing.
[0023] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. Attached Figure Description
[0024] Figure 1 This is a schematic diagram of the structure of this utility model;
[0025] Figure 2 This is a partially enlarged schematic diagram of the present invention;
[0026] Labeling notes: 1. Housing; 2. Input shaft; 21. Oil seal step; 22. First skeleton oil seal; 23. Second skeleton oil seal; 24. Round nut; 25. Locking washer; 26. Oil retaining ring; 27. Elastic retaining ring; 3. Input gear; 4. Input flange; 41. Bearing chamber; 42. First tapered roller bearing; 43. Second tapered roller bearing; 44. Mounting convex ring; 45. Oil injection hole; 46. Grease nipple; 47. Vent hole; 48. Vent cap; 5. Through cover; 6. Lubrication chamber. Detailed Implementation
[0027] The technical solutions in the embodiments of this utility model will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model. Example 1:
[0028] like Figure 1 , Figure 2 The reducer input dry well double-seal structure shown includes a housing 1, an input shaft 2, and an input gear 3. The input gear 3 is located inside the housing 1 and is connected to the input shaft 2 via a key. An input flange 4 is fitted onto the input shaft 2 on the housing 1. The input flange 4 has a bearing chamber 41. The input shaft 2 has a first tapered roller bearing 42 and a second tapered roller bearing 43 arranged opposite each other inside the bearing chamber 41. The input shaft 2 has an oil seal step 21 near one end of the housing 1, and a first skeleton oil seal 22 is provided on the oil seal step 21. The input shaft 2 is covered by the flange chamber. The flange is covered with a transparent cover 5, on which a second skeleton oil seal 23 is fixed. A mounting convex ring 44 is provided in the flange chamber. One end of the first tapered roller bearing 42 abuts against the end face of the oil seal step 21, and the other end abuts against the end face of the mounting convex ring 44. The second tapered roller bearing 43 abuts against the end face of the mounting convex ring 44 relative to one end face of the first tapered roller bearing 42. The input shaft 2 is provided with a round nut 24 at the second tapered roller bearing 43 to prevent the second tapered roller bearing 43 from moving axially. A retaining washer 25 is also provided between the round nut 24 and the second tapered roller bearing 43.
[0029] The housing 1 is bolted to the input flange 4. The input gear 3 is mounted inside the housing 1 via a flat key at the end of the input shaft 2. The first skeleton oil seal 22 on the oil seal step 21 isolates the bearing chamber 41 from the inner cavity of the housing 1, preventing the grease in the bearing chamber 41 and the lubricating oil in the inner cavity of the housing 1 from interpenetrating. Simultaneously, a transparent cover 5 is provided at the end of the bearing chamber 41 of the input flange 4, and a second skeleton oil seal 23 is added to the transparent cover 5. This allows observation of the lubricating grease, the first tapered roller bearing 42, and the second tapered roller bearing 43 within the bearing chamber 41 through the transparent cover 5, while also achieving the function of isolating leaking media and providing dual protection, significantly improving the reliability of the seal. Furthermore, the first tapered roller bearing 42 and the second tapered roller bearing 43 are mounted back-to-back on the input shaft 2, capable of simultaneously bearing the radial and axial loads of the input shaft 2, improving the load capacity and stability of the input shaft 2 during operation.
[0030] The first tapered roller bearing 42 is first mounted on the input shaft 2 and contacts the end face of the oil seal step 21. Then, the input shaft 2 passes through the bearing housing 41, so that the other end face of the first tapered roller bearing 42 abuts against the end face of the mounting cam 44, thereby axially fixing the first tapered roller bearing 42. Then, the second tapered roller bearing 43 abuts against the other end face of the mounting cam 44. The round nut 24 is fixed on the input shaft 2 by threaded rotation, and the preload is used to press the second tapered roller bearing 43, effectively preventing the second tapered roller bearing 43 from shifting axially. The retaining washer 25 further improves the limiting ability of the round nut 24 for the second tapered roller bearing 43. Furthermore, the first tapered roller bearing 42 and the second tapered roller bearing 43, in cooperation with the mounting cam 44, can withstand greater axial force and are more adaptable to working conditions with frequent impacts or heavy loads. Example 2:
[0031] Based on Embodiment 1, Embodiment 2 differs in that the side wall of the input flange 4 is also provided with an oil injection hole 45 and a vent hole 47 that connect to the bearing chamber 41. The oil injection hole 45 is equipped with a grease nipple 46, and the vent hole 47 is equipped with a vent cap 48.
[0032] The inner rings of the first tapered roller bearing 42 and the second tapered roller bearing 43 are in contact with the input shaft 2, and the outer rings are in contact with the inner wall of the bearing housing 41. A lubrication chamber 6 is formed between the first tapered roller bearing 42, the second tapered roller bearing 43, and the mounting ring 44. Since the bearing needs to move the grease in the bearing housing 41 when it rotates, the grease between the first tapered roller bearing 42 and the second tapered roller bearing 43 will be rotated to the outside of the lubrication chamber 6, making it difficult to ensure that the first tapered roller bearing 42 and the second tapered roller bearing 43 are effectively lubricated. Therefore, by opening an oil injection hole 45 on the side of the input flange 4 to connect to the lubrication chamber 6, and setting a grease nipple 46 at the end of the oil injection hole 45, the grease can easily enter the lubrication chamber 6 through the oil injection hole 45, thereby effectively lubricating the first tapered roller bearing 42 and the second tapered roller bearing 43, delaying the fatigue damage of the bearing, and significantly increasing the service life of the bearing.
[0033] When the reducer is running continuously at high temperature or high intensity, the internal temperature of the reducer will rise, causing the lubricating oil and grease inside the reducer and input flange 4 to vaporize. The internal air pressure will continue to increase, which can easily lead to damage to the oil seal or connection. Therefore, by opening a vent hole 47 through the side wall of the input flange 4, the vent cap 48 on the vent hole 47 can open when the internal air pressure of the reducer reaches the threshold, thereby venting and depressurizing the reducer, preventing the internal air pressure from being too high, and thus protecting the sealing structure of the reducer.
[0034] An oil baffle ring 26 is provided inside the housing 1 for the input shaft 2. One end face of the oil baffle ring 26 abuts against the inner wall of the housing 1, and the other end is snapped with an elastic retaining ring 27. The oil baffle ring 26 is limited by the elastic retaining ring 27 and the inner wall of the oil tank 1. Since the lubricants in the reducer cavity and the bearing chamber 41 of the input flange 4 are different, the reducer usually uses lubricating oil, while the bearing chamber 41 usually uses lubricating grease. The mixing of the two will reduce the lubricating ability of the lubricating oil and the lubricating grease. The oil baffle ring 26 can not only cover the gap between the first skeleton oil seal 22 and the input shaft 2, but also throw the lubricating oil back into the oil pool in the housing 1 or change the direction of the lubricating oil return when the input shaft 2 rotates, thus preventing the lubricating oil from seeping into the bearing chamber 41 through the gap and mixing with the lubricating grease. This ensures the stability of the lubricating grease performance and further improves the sealing ability of the first skeleton oil seal 22 for the reducer cavity and the bearing chamber 41.
[0035] The embodiments described above are merely examples of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these modifications and improvements all fall within the protection scope of this utility model.
Claims
1. A double-sealed input shaft structure for a speed reducer, comprising a housing, an input shaft, and an input gear, wherein the input gear is disposed within the housing, the input gear is connected to the input shaft via a key, and an input flange is fitted onto the input shaft on the housing, characterized in that: The input flange is provided with a bearing chamber. The input shaft is provided with a first tapered roller bearing and a second tapered roller bearing arranged opposite to each other in the bearing chamber. The input shaft is provided with an oil seal step near one end of the housing. The oil seal step is provided with a first skeleton oil seal. The input shaft is covered by a transparent cover in the flange chamber. A second skeleton oil seal is fixed on the transparent cover.
2. The speed reducer input dry sump double seal structure of claim 1, wherein: The flange chamber is provided with a mounting convex ring. One end of the first tapered roller bearing abuts against the end face of the oil seal step, and the other end abuts against the end face of the mounting convex ring. The second tapered roller bearing abuts against the end face of the mounting convex ring relative to one end face of the first tapered roller bearing. The input shaft is provided with a round nut at the second tapered roller bearing to prevent axial movement of the second tapered roller bearing. A locking washer is also provided between the round nut and the second tapered roller bearing.
3. The speed reducer input dry sump double seal structure of claim 2, wherein: A lubrication chamber is formed between the first tapered roller bearing, the second tapered roller bearing, and the mounting ring. An oil injection hole communicating with the lubrication chamber is provided on the side wall of the input flange, and a grease nipple is engaged with the oil injection hole.
4. The speed reducer input dry sump double seal structure of claim 3, wherein: The input flange is also provided with a vent hole that penetrates the side wall, and a vent cap is installed in the vent hole.
5. The speed reducer input dry sump double seal structure of claim 4, wherein: The input shaft is provided with an oil baffle ring inside the housing. One end face of the oil baffle ring abuts against the inner wall of the housing, and the other end is engaged with an elastic retaining ring.