Static sealing structure for sealing top drive bearing lubricating oil, top drive and top drive system

Abstract

The application discloses a kind of static seal structure of sealing top drive bearing lubricating oil, top drive and top drive system, it is related to well drilling device structure field;Static seal structure, including the installation cavity formed by box and main shaft, the installation cavity is used to install bearing;The oil inlet and oil return port that are communicated with installation cavity are opened in the box;Further include isolation cylinder;Isolation cylinder is assembled in installation cavity with the attitude of being able to surround main shaft;Oil inlet and oil return port are all located the outside of isolation cylinder;The lower end of isolation cylinder is sealedly connected with the lower surface of installation cavity;The height of the upper end of isolation cylinder in space is higher than the highest height of oil return port;Top drive includes box, main shaft, bearing and the static seal structure described above;Top drive system includes lubricating oil power source and the top drive described above.The application effectively solves the problem of lubricating oil leakage by changing rotary oil seal into static seal.

Description

Technical Field

[0001] This invention relates to the field of drilling equipment structure, and in particular to a static sealing structure for sealing the lubricating oil of a top drive bearing, a top drive, and a top drive system. Background Technology

[0002] Top drive drilling rigs (referred to as "top drives") are one of the core equipment of modern oil drilling rigs. Their performance directly determines the drilling efficiency and safety of drilling operations, especially deep wells, ultra-deep wells, and wells with complex structures.

[0003] A top drive consists of a spindle and a housing. Since the housing is a stationary component and the spindle is a rotating component, there is relative rotational motion between the spindle and the housing. Because the top drive operates in a vertical position, bearings are usually placed between the spindle and the housing to ensure the spindle's rotational stability and to resist the spindle's gravity load. To ensure the normal operation and service life of the bearings, they need to be lubricated and cooled using lubricating oil (referred to as lubrication). Therefore, in a top drive, higher requirements are placed on the sealing reliability and sealing life of the lubricating oil.

[0004] Currently, most top drive lubrication systems use rotary oil seals for sealing. However, prolonged rotation and friction can shorten the seal life, weaken the sealing effect, and lead to oil leakage. Furthermore, maintenance is difficult, time-consuming, and costly. To address the leakage problem of rotary oil seals, additional leakage prevention structures are often added, such as using a series connection to add an auxiliary oil tank to reduce the risk of leakage. For example, Chinese patent CN115584925A discloses a drilling top drive system that adds a lower sealing component axially below the top drive gearbox. This increases the working height of the top drive and correspondingly reduces the safe operating space. This not only increases the working height of the top drive but also increases manufacturing costs and easily creates a siphon effect, resulting in poor performance and failing to completely solve the sealing leakage problem. Summary of the Invention

[0005] The purpose of this invention is to provide a static sealing structure for sealing the lubricating oil in a top drive bearing, a top drive, and a top drive system, thereby effectively solving the problem of lubricating oil leakage by converting a rotary oil seal into a static seal.

[0006] The technical solution adopted in this invention is as follows: a static sealing structure for sealing the lubricating oil of a top drive bearing, comprising a mounting cavity formed by a housing and a main shaft, the mounting cavity being used to mount the bearing; the housing having an oil inlet and an oil return port communicating with the mounting cavity; and further comprising an isolation cylinder; wherein: The isolation cylinder is assembled in the mounting cavity in a manner that surrounds the main shaft; both the oil inlet and the oil return port are located on the outside of the isolation cylinder; the lower end of the isolation cylinder is sealed to the bottom of the mounting cavity; the upper end of the isolation cylinder is higher than the maximum height of the oil return port in space.

[0007] Furthermore, the top of the mounting cavity is provided with an annular groove that can surround the main shaft; the upper end of the isolation cylinder extends into the groove and there is a gap between it and the inner wall of the groove.

[0008] Furthermore, a lubricating layer is sealed and fixed at the lower end of the isolation cylinder, and the lubricating layer is detachably connected to the mounting cavity; a sealing ring is provided between the lower surface of the lubricating layer and the lower surface of the mounting cavity.

[0009] Furthermore, a first limiting groove is provided at the bottom of the mounting cavity, and a limiting boss is provided on the lower surface of the lubrication layer, which is embedded in the first limiting groove.

[0010] A top drive includes a housing, a spindle, bearings, and the aforementioned static sealing structure; wherein: The isolation cylinder divides the mounting cavity into a first chamber and a second chamber, with the second chamber located between the inner wall of the isolation cylinder and the main shaft. The bearing is installed in the first chamber. The upper end face of the bearing mates with the surface on the main shaft that serves as the top of the mounting cavity. The lower end face of the bearing mates with the surface on the housing that serves as the bottom of the mounting cavity.

[0011] Furthermore, the spindle has a step, and the lower surface of the step serves as the top surface of the mounting cavity.

[0012] Furthermore, there are safety gaps between the outer wall of the isolation cylinder and the inner wall of the bearing, and between the inner wall of the isolation cylinder and the outer wall of the main shaft.

[0013] Furthermore, a rotary seal is provided in the second chamber, which is used to seal the safety gap between the inner wall of the isolation cylinder and the outer wall of the main shaft.

[0014] Furthermore, a second limiting groove is provided on the upper surface of the lubrication layer, and the lower end of the bearing is embedded in the second limiting groove.

[0015] A top drive system includes a lubricating oil power source and the top drive; wherein: The lubricating oil power source has an oil outlet and an oil return port; the oil outlet is connected to the oil inlet; and the oil return port is connected to the oil return port.

[0016] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. This invention achieves the sealing of lubricating oil by setting an isolation cylinder and ensuring that the upper end of the isolation cylinder is higher than the highest height of the oil return port in space, thereby confining the lubricating oil within the installation cavity. 2. Due to the sealed connection between the isolation cylinder and the lower surface of the mounting cavity, combined with the beneficial effect 1 and the safety clearance, the present invention achieves static sealing, eliminating concerns about seal damage caused by spindle rotation friction and ensuring long-life operation of the top drive; 3. Because the isolation cylinder is set inside the mounting cavity, the present invention does not increase the axial height of the seal, thus achieving no increase in the working height of the top drive; 4. This invention only adds an isolation cylinder to achieve sealing of the lubricating oil, which is simple in structure and low in manufacturing cost. Attached Figure Description

[0017] The present invention will be described by way of example and with reference to the accompanying drawings, wherein: Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 for Figure 1 Enlarged view of point A in the middle; The markings in the diagram are: 1-spindle; 11-groove; 12-step; 2-box; 21-oil inlet; 22-oil return port; 23-first limiting groove; 3-installation cavity; 4-isolation cylinder; 5-bearing; 6-lubricating layer; 61-second limiting groove; 7-sealing ring; 8-rotary seal. Detailed Implementation

[0018] In the description of this specification, it should be noted that if terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," or "outer" appear to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use, they are only for the convenience of describing this specification and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this specification.

[0019] In the description of this specification, it should also be noted that, unless otherwise expressly specified and limited, the terms “set up,” “install,” “connect,” and “link” should be interpreted broadly. For example, a link can be a fixed link, a detachable link, or an integral link; it can be a mechanical link or an electrical link; it can be a direct link or an indirect link through an intermediate medium; it can be a connection within two components.

[0020] Example 1 like Figures 1-2 As shown, a static sealing structure for sealing top drive bearing lubricating oil includes a mounting cavity 3 formed by a housing 2 and a main shaft 1. Specifically, the top surface and the surface near the main shaft 1 of the mounting cavity 3 are the surfaces of the main shaft 1; the bottom surface and the surface away from the main shaft 1 are the surfaces of the housing 2. This mounting cavity 3 is used to mount a bearing 5. The housing 2 has an oil inlet 21 and an oil return port 22 communicating with the mounting cavity 3. It also includes an isolation cylinder 4. Wherein: The isolation cylinder 4 is assembled in the mounting cavity 3 in a posture that can surround the main shaft 1; the oil inlet 21 and the oil return port 22 are both located on the outside of the isolation cylinder 4; the lower end of the isolation cylinder 4 is sealed to the bottom of the mounting cavity 3; the upper end of the isolation cylinder 4 is higher than the highest height of the oil return port 22 in space, that is, there is a height difference H1 between the upper end of the isolation cylinder 4 and the highest position of the oil return port 22 in space.

[0021] In this embodiment, when the lubricating oil enters the mounting cavity 3 from the oil inlet 21, since the upper end of the isolation cylinder 4 is higher than the highest height of the return oil port 22, the lubricating oil will preferentially flow back from the return oil port 22, and will not overflow the isolation cylinder 4 and leak from the assembly gap between the housing 2 and the spindle 1. This achieves the purpose of using the isolation cylinder 4 to confine the lubricating oil within the mounting cavity 3, thereby achieving the sealing of the lubricating oil.

[0022] Furthermore, in this embodiment, the isolation cylinder 4 is disposed within the mounting cavity 3, without increasing the axial height of the seal, thereby achieving no increase in the working height of the top drive; compared to the patent with publication number CN115584925A mentioned in the background art, this application does not have a lower sealing component, thus having the advantage of not increasing the working height of the top drive.

[0023] Compared to the patent with publication number CN115584925A mentioned in the background art, which uses an umbrella-like structure for the upper oil seal to prevent oil leakage because the lubricating oil flows directly downwards from the gearbox, this invention requires two additional sets of seals (first and second sealing rings) and additional positioning screws, resulting in a complex structure, difficult installation, and a risk of the positioning screws falling off, increasing the risk of oil leakage. In this embodiment, only an isolation cylinder 4 is added inside the mounting cavity 3 to achieve the sealing of the lubricating oil, resulting in a simple structure and low manufacturing cost.

[0024] In this embodiment, the isolation cylinder 4 can be directly installed in the mounting cavity 3 by welding or other means, thus achieving a sealed connection between the isolation cylinder 4 and the lower surface of the mounting cavity 3; of course, a detachable sealed connection can also be achieved by using the lubricating partition 6 in conjunction with the sealing ring 7, as described in Embodiment 2 below.

[0025] In this embodiment, at least one oil inlet 21 and one oil return port 22 can be provided according to the actual on-site production needs of the top drive. However, the position of the oil return port 22 needs to meet the premise of the minimum working fluid level height for lubrication of the bearing 5, and also needs to meet the requirement of this embodiment that it is lower than the upper end of the isolation cylinder 4 in space, so as to ensure that the bearing 5 can be effectively lubricated and cooled while confining the lubricating oil in the mounting cavity 3, and ensuring that the static sealing structure disclosed in this embodiment can effectively seal the lubricating oil.

[0026] In this embodiment, the shapes of the oil inlet 21 and the oil return port 22 can be set according to actual needs, including but not limited to circles, polygons, irregular shapes, etc.

[0027] Example 2 On the basis of Example 1, further specific implementable embodiments are proposed.

[0028] If the lubricating oil does not need to occupy the entire height of the installation cavity 3, the upper end of the isolation cylinder 4 can be close to the top of the installation cavity 3; however, in order to ensure effective lubrication and cooling of the bearing 5 by the lubricating oil, usually, based on the actual situation that "the surface on the main shaft 1 that serves as the upper surface of the installation cavity 3 needs to cooperate with the upper end of the bearing 5, and the surface on the box body 2 that serves as the lower surface of the installation cavity 3 needs to cooperate with the lower surface of the bearing 5", the lubricating oil needs to occupy the entire height of the installation cavity 3, that is, the lubricating oil needs to submerge the bearing 5; therefore, in a feasible implementation manner, an annular groove 11 is opened at the top of the installation cavity 3, and the groove 11 can surround the main shaft 1; the upper end of the isolation cylinder 4 extends into the groove 11 and there is a gap between the upper end of the isolation cylinder 4 and the inner wall of the groove 11; by providing the annular groove 11, a receiving space is provided for the upper end of the isolation cylinder 4; at the same time, by providing the gap, it can be avoided that the isolation cylinder 4 contacts the main shaft 1, ensuring that the isolation cylinder 4 will not be worn, and further ensuring that the isolation cylinder 4 can work for a long time.

[0029] For the top of the installation cavity 3 provided with the groove 11, there are the following several implementation manners.

[0030] The first implementation manner is that the main shaft 1 has a step 12, and the lower surface of the step 12 serves as the surface of the top of the installation cavity 3, and the groove 11 can be provided on the lower surface of the step 12.

[0031] The second implementation manner is that the surface that serves as the top of the installation cavity 3 is a structure on the box body 2. For example, the box body 2 has a groove with a "匚" - shaped cross - section, and the upper surface of the groove serves as the surface of the top of the installation cavity 3. Therefore, the groove 11 can be provided on the box body 2.

[0032] The third implementation manner is that the box body 2 and the main shaft 1 cooperate to form the groove 11.

[0033] In a feasible implementation manner, a lubricating isolation layer 6 is hermetically fixed to the lower end of the isolation cylinder 4. The lubricating isolation layer 6 and the isolation cylinder 4 can be integrally formed components or can be connected by welding; the lubricating isolation layer 6 is detachably connected to the installation cavity 3; a sealing ring 7 is provided between the lower surface of the lubricating isolation layer 6 and the lower surface of the installation cavity 3, and the sealing ring 7 is a static sealing ring; through the sealing ring 7, the sealing between the lubricating isolation layer 6 and the lower surface of the installation cavity 3 is achieved, and further the sealing between the isolation cylinder 4 and the lower surface of the installation cavity 3 is achieved.

[0034] Furthermore, the detachable connection between the lubrication partition 6 and the mounting cavity 3 facilitates later maintenance and replacement, and also meets the disassembly and maintenance requirements of the top drive. In a feasible implementation, a first limiting groove 23 is provided at the bottom of the mounting cavity 3, and the lower surface of the lubrication partition 6 has an annular limiting boss. The limiting boss is embedded in the first limiting groove 23. Through the cooperation between the first limiting groove 23 and the limiting boss, not only is the detachable connection between the lubrication partition 6 and the mounting cavity 3 realized, but the lubrication partition 6 is also limited to prevent the isolation cylinder 4 from shifting position and causing friction between it and the bearing 5 or the main shaft 1, resulting in unnecessary damage.

[0035] Example 3 like Figures 1-2 As shown, a top drive includes a housing 2, a spindle 1, a bearing 5, and the static sealing structure described in Examples 1-2; wherein: The isolation cylinder 4 divides the mounting cavity 3 into a first chamber and a second chamber. The second chamber is located between the inner wall of the isolation cylinder 4 and the main shaft 1. That is, the upper surface, distal surface, and lower surface of the mounting cavity 3 and the outer wall of the isolation cylinder 4 form the first chamber, and the second chamber is inside the isolation cylinder 4. The bearing 5 is installed in the first chamber. The upper end face of the bearing 5 mates with the surface on the main shaft 1 that serves as the top of the mounting cavity 3. The lower end face of the bearing 5 mates with the surface on the housing 2 that serves as the bottom of the mounting cavity 3. In this embodiment, the stationary component in the top drive is the housing 2, and the moving component is the main shaft 1. Therefore, the upper end of the bearing 5 will rotate with the main shaft 1. The lower end face of the bearing 5 is in contact with the surface on the housing 2 that serves as the bottom of the mounting cavity 3, so the lower end of the bearing 5 is a stationary component. The isolation cylinder 4 is installed on the lower surface of the mounting cavity 3, so the isolation cylinder 4 is a stationary component. Thus, the first chamber forms a statically sealed chamber that confines the lubricating oil. Based on the bearing 5 being installed in the first chamber, the lubrication and cooling of the bearing 5 are effectively achieved, while the lubricating oil is also sealed. Since the bearing 5 needs to support the spindle 1, the upper end of the bearing 5 needs to cooperate with the spindle 1. Further feasiblely, as stated in Embodiment 2, the spindle 1 has a step 12, and the lower surface of the step 12 serves as the top surface of the mounting cavity 3. That is, the bearing 5 supports the spindle 1 by supporting the step 12.

[0036] Of course, a limiting groove can be provided on the lower surface of step 12 so that the upper end of bearing 5 can be embedded in the limiting groove to avoid relative position slippage between spindle 1 and bearing 5.

[0037] In this embodiment, the isolation cylinder 4 is disposed in the mounting cavity 3, and the bearing 5 is also disposed in the mounting cavity 3. The bearing 5 and the isolation cylinder 4 are arranged radially, so the axial height of the seal is not increased, thereby achieving no increase in the working height of the top drive.

[0038] In this embodiment, the top drive only needs to be equipped with an isolation cylinder 4 to achieve the sealing of the lubricating oil, which is simple in structure and low in manufacturing cost.

[0039] Example 4 Based on Example 3, further feasible implementation methods are proposed.

[0040] In one feasible implementation, safety gaps S1 and S2 exist between the outer wall of the isolation cylinder 4 and the inner wall of the bearing 5, and between the inner wall of the isolation cylinder 4 and the outer wall of the main shaft 1. The existence of these safety gaps prevents the main shaft 1 from contacting the inner wall of the isolation cylinder 4 and the inner wall of the bearing 5 near the upper end with the outer wall of the isolation cylinder 4, ensuring that the isolation cylinder 4 will not wear out, thereby ensuring that the isolation cylinder 4 can work for a long time.

[0041] In one feasible implementation, a rotary seal 8 is provided in the second chamber. The rotary seal 8 is used to seal the safety gap between the inner wall of the isolation cylinder 4 and the outer wall of the main shaft 1. The rotary seal 8 is used to prevent lubricating oil from overflowing the upper end of the isolation cylinder 4 and entering the second chamber, causing lubricating oil leakage.

[0042] Meanwhile, since the lubricating oil is confined in the first chamber under normal circumstances, there will be no lubricating oil in the second chamber; therefore, the rotary seal 8 in the second chamber also has a dustproof function, preventing dust from entering the first chamber from the second chamber and contaminating the lubricating oil, thus ensuring the quality of the lubricating oil for long-term use.

[0043] In one feasible implementation, a second limiting groove 61 is provided on the upper surface of the lubrication partition 6, and the lower end of the bearing 5 is embedded in the second limiting groove 61. Based on the above-mentioned limitation of the lubrication partition 6 by the cooperation of the first limiting groove 23 and the limiting boss, the position of the lubrication partition 6 is stable. The bearing 5 is further limited by the second limiting groove 61, so that the position of the bearing 5 is stable and the bearing 5 is prevented from shifting during operation. With the limiting groove on the step 12 described in embodiment 3, the relative position of the spindle 1, the bearing 5, and the housing 2 will not slip.

[0044] Example 4 like Figures 1-2 As shown, a top drive system includes a lubricating oil power source and the top drive; wherein: The lubricating oil power source has an oil outlet and an oil return port; the oil outlet is connected to the oil inlet 21; and the oil return port is connected to the oil return port 22.

[0045] Based on the presence of the aforementioned isolation cylinder 4, when the top drive system is in operation, it is only necessary to control the flow rate so that the return port 22 can meet the return flow of lubricating oil, thereby enabling the isolation cylinder 4 to confine the lubricating oil in the first chamber and ensure effective sealing.

[0046] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A static sealing structure for sealing the lubricating oil of a top drive bearing, comprising a mounting cavity (3) formed by a housing (2) and a main shaft (1), the mounting cavity (3) being used to mount a bearing (5); the housing (2) having an oil inlet (21) and an oil return port (22) communicating with the mounting cavity (3); characterized in that: It also includes an isolation cylinder (4); wherein: The isolation cylinder (4) is assembled in the mounting cavity (3) in a posture that can surround the main shaft (1); the oil inlet (21) and the oil return port (22) are both located on the outside of the isolation cylinder (4); the lower end of the isolation cylinder (4) is sealed to the bottom of the mounting cavity (3); the upper end of the isolation cylinder (4) is higher than the maximum height of the oil return port (22) in space.

2. The static sealing structure according to claim 1, characterized in that: The top of the mounting cavity (3) is provided with an annular groove (11), which can surround the main shaft (1); the upper end of the isolation cylinder (4) extends into the groove (11) and there is a gap between it and the inner wall of the groove (11).

3. The static sealing structure according to claim 1, characterized in that: The lower end of the isolation cylinder (4) is sealed with a lubricating partition (6), which is detachably connected to the mounting cavity (3); a sealing ring (7) is provided between the lower surface of the lubricating partition (6) and the lower surface of the mounting cavity (3).

4. The static sealing structure according to claim 3, characterized in that: The bottom of the mounting cavity (3) is provided with a first limiting groove (23), and the lower surface of the lubrication layer (6) has a limiting boss, which is embedded in the first limiting groove (23).

5. A top drive, characterized in that: Includes a housing (2), a main shaft (1), a bearing (5), and a static sealing structure as described in any one of claims 1-4; wherein: The isolation cylinder (4) divides the mounting cavity (3) into a first chamber and a second chamber. The second chamber is located between the inner wall of the isolation cylinder (4) and the main shaft (1). The bearing (5) is installed in the first chamber. The upper end face of the bearing (5) is in contact with the surface on the main shaft (1) that serves as the top of the mounting cavity (3). The lower end face of the bearing (5) is in contact with the surface on the housing (2) that serves as the bottom of the mounting cavity (3).

6. The top drive according to claim 5, characterized in that: The main shaft (1) has a step (12), the lower surface of which serves as the top surface of the mounting cavity (3).

7. The top drive according to claim 5, characterized in that: There are safety gaps between the outer wall of the isolation cylinder (4) and the inner wall of the bearing (5), and between the inner wall of the isolation cylinder (4) and the outer wall of the main shaft (1).

8. The top drive according to claim 7, characterized in that: The second chamber is provided with a rotary seal (8), which is used to seal the safety gap between the inner wall of the isolation cylinder (4) and the outer wall of the main shaft (1).

9. The top drive according to claim 5, characterized in that: The upper surface of the lubrication layer (6) is provided with a second limiting groove (61), and the lower end of the bearing (5) is embedded in the second limiting groove (61).

10. A top drive system, characterized in that: Includes a lubricating oil power source and a top drive as described in any one of claims 5-9; wherein: The lubricating oil power source has an oil outlet and an oil return port; the oil outlet is connected to the oil inlet (21); the oil return port is connected to the oil return port (22).

Images