A high-reliability dynamic seal structure for drive shafts

Abstract

This utility model discloses a high-reliability dynamic sealing structure for a drive shaft, including a mounting base, a motor outer tube, and a motor. The mounting base is connected to the motor outer tube, and the motor is disposed inside the motor outer tube. A drive shaft is disposed inside the mounting base and is connected to the output shaft of the motor via a coupling. A sealing assembly is installed in the space formed by the drive shaft and the mounting base. The sealing assembly includes a compression plug, a first dynamic seal, and a second dynamic seal. The compression plug is disposed at both ends of the drive shaft. The second dynamic seal is disposed inside the compression plug closer to the motor end, and the first dynamic seal is disposed inside the compression plug farther from the motor end. Silicone oil is filled between the first and second dynamic seals. The first and second dynamic seals form a redundant seal, improving the reliability of long-term sealing, and the silicone oil prevents micro-leakage of external high-pressure gas into the internal environment of the instrument during long-term sealing.

Description

Technical Field

[0001] This utility model relates to the field of oilfield downhole equipment, specifically to a highly reliable dynamic sealing structure for a drive shaft. Background Technology

[0002] Due to their design requirements, downhole instruments in oilfields often contain motors. These motors rotate to drive external movable mechanisms, enabling the designed functions. As precision electronic components, motors cannot withstand high pressure or immersion in external media and must be tightly protected within the instrument's casing during operation. Therefore, the design of dynamic seals at the motor's rotating shaft is frequently required in downhole instrument design.

[0003] Compared to static seals, dynamic seals in downhole environments require relative movement between sealing components. The seal must not only tightly seal against the sealing area to block external high-pressure media under high pressure, but also minimize the frictional resistance to the sealed moving parts caused by pre-tightening deformation, to avoid motor power loss or even motor failure. Therefore, dynamic seal design in downhole high-pressure environments is much more difficult than static seal design, and the reliability of dynamic seal structures for long-term downhole use is also low.

[0004] Furthermore, with the increasing application scenarios of downhole instruments in oilfields, the presence of gas in downhole media is also becoming more frequent. Sealing design in gaseous environments is far more challenging than in liquid environments, primarily due to the compressibility and greater fluidity of gases compared to liquids. Under the same sealing gap and surface finish conditions, gases are more prone to leakage. In addition, the small molecular size and low viscosity of gases result in significantly greater permeability than liquids, allowing them to seep through minute pores or cracks in materials.

[0005] For the reasons mentioned above, improving the long-term operational reliability of dynamic seals for downhole instruments, especially those that need to be placed downhole for extended periods, has become a pressing technical challenge for the industry, particularly when used in gas-bearing environments. Utility Model Content

[0006] To address the aforementioned issues, this invention provides a highly reliable dynamic sealing structure for drive shafts. By incorporating multiple dynamic sealing elements, the redundancy of the drive shaft seal is increased, improving the reliability of long-term sealing. Furthermore, the structure is filled with silicone oil to prevent micro-leakage of external high-pressure gas into the internal environment of the instrument during long-term sealing.

[0007] To achieve the above objectives, this utility model adopts the following technical solution: a high-reliability dynamic sealing structure for a drive shaft, comprising a mounting base, a motor outer tube, and a motor. The mounting base is connected to the motor outer tube, and the motor is disposed inside the motor outer tube. A drive shaft is disposed inside the mounting base, and the drive shaft is connected to the output shaft of the motor via a coupling. A sealing assembly is installed in the space formed by the drive shaft and the mounting base. The sealing assembly includes a compression plug, a first dynamic seal, and a second dynamic seal. The compression plug is disposed at both ends of the drive shaft. The second dynamic seal is disposed inside the compression plug at the end closer to the motor, and the first dynamic seal is disposed inside the compression plug at the end farther from the motor. Silicone oil is filled between the first dynamic seal and the second dynamic seal.

[0008] The first dynamic seal fitted on the end of the drive shaft away from the motor consists of at least two dynamic sealing rings, with a spacer ring between adjacent dynamic sealing rings.

[0009] The second dynamic seal, which is fitted onto the end of the drive shaft closest to the motor, is a dynamic sealing ring, with spacers on both sides of the dynamic sealing ring.

[0010] The second seal is provided with a sealing plug on the outside, and a first O-ring is provided between the sealing plug and the mounting base.

[0011] The drive shaft has a shoulder in the middle, and a thrust bearing and a deep groove ball bearing are respectively installed on both sides of the shoulder.

[0012] The compression plug is equipped with an anti-loosening screw.

[0013] The motor outer tube is threadedly connected to the mounting base, and a second O-ring is provided at the connection.

[0014] The beneficial effects of this utility model are as follows: Compared with the prior art, this utility model has a compact overall structure and high space utilization. By setting a first seal and a second seal at both ends of the transmission shaft, the redundancy of the seal is increased. When the first seal fails, the second seal continues to play a sealing role, preventing the leaked medium from entering the motor's internal installation space and damaging the motor. At the same time, for sealing conditions in a gas environment, silicone oil is filled between the first seal and the second seal to establish a physical barrier similar to a "liquid seal". When a gas seal fails at the first seal, the silicone oil can effectively block the penetration of the invading gas medium, improving the reliability of the seal in a gas environment. Attached Figure Description

[0015] The present invention will be further described below with reference to the accompanying drawings:

[0016] Figure 1 This is a schematic diagram of the structure of this utility model;

[0017] In the diagram: 1. Motor; 2. Motor outer tube; 3. Drive shaft; 4. Compression plug; 5. Sealing plug; 6. First O-ring; 7. Spacer ring; 8. Dynamic seal ring; 9. Second O-ring; 10. Thrust bearing; 11. Deep groove ball bearing; 12. Mounting base; 13. Anti-loosening screw; 14. Coupling. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments.

[0019] The technical solution of this utility model will be described in detail below with specific embodiments. The following specific embodiments can be selected to be combined or substituted with each other according to the actual situation, and the same or similar concepts or processes may not be described again in some embodiments.

[0020] Example 1

[0021] like Figure 1 As shown, this utility model provides a high-reliability dynamic sealing structure for a drive shaft, including a mounting base 12, a motor outer tube 2, and a motor 1. The mounting base 12 is connected to the motor outer tube 2, and the motor 1 is disposed inside the motor outer tube 2. A drive shaft 3 is disposed inside the mounting base 12, and the drive shaft 3 is connected to the output shaft of the motor 1 through a coupling 14. A sealing assembly is installed in the space formed by the drive shaft 3 and the mounting base 12. The sealing assembly includes a compression plug 4, a first dynamic seal, and a second dynamic seal. The compression plug 4 is disposed at both ends of the drive shaft 3. The second dynamic seal is disposed inside the compression plug 4 near the motor 1, and the first dynamic seal is disposed inside the compression plug 4 away from the motor 1. Silicone oil is filled between the first dynamic seal and the second dynamic seal.

[0022] By setting a first seal and a second seal at both ends of the drive shaft, the redundancy of the seal is increased. When the first seal fails, the second seal continues to seal, preventing leaked media from entering the motor's internal installation space and damaging the motor. At the same time, for sealing conditions in a gas environment, silicone oil is filled between the first and second seals to create a physical barrier similar to a "liquid seal." When a gas seal fails at the first seal, the silicone oil can effectively block the penetration of the invading gas medium, improving the reliability of the seal in a gas environment.

[0023] Specifically, the first dynamic seal fitted on the end of the drive shaft 3 away from the motor 1 consists of at least two dynamic sealing rings 8, with a spacer ring 7 between adjacent dynamic sealing rings 8. By setting multiple dynamic sealing rings 8 as the first layer of sealing protection, the sealing effect is enhanced, and the spacer ring 7 supports both sides of the dynamic sealing rings 8, reducing excessive axial pressure on the dynamic sealing rings 8 and effectively improving the stability of the seal.

[0024] Specifically, the second dynamic seal fitted on the end of the drive shaft 3 near the motor 1 is a dynamic sealing ring 8, with spacer rings 7 on both sides of the dynamic sealing ring 8. A sealing plug 5 is provided on the outer side of the second seal, and a first O-ring 6 is provided between the sealing plug 5 and the mounting base 12. The dynamic sealing ring 8 and the first O-ring 6, located near the motor 1, serve as a second layer of sealing protection, increasing the sealing redundancy of the structure. This ensures that even if the first layer of sealing protection fails, there is still a second sealing barrier to continue to provide a sealing effect.

[0025] Furthermore, the drive shaft 3 has a shoulder in the middle, and a thrust bearing 10 and a deep groove ball bearing 11 are respectively installed on both sides of the shoulder. The axial force generated by the drive shaft 3 under external pressure acts on the thrust bearing 10, which can reduce the rotational assistance of the drive shaft 3 under axial force. The deep groove ball bearing 11 is used to reduce the rotational friction of the drive shaft 3 and also plays a certain supporting role. This dual bearing installation ensures the smoothness and reliability of the rotation of the drive shaft 3 under the action of sealing force.

[0026] Furthermore, the compression plug 4 is equipped with an anti-loosening screw 13 to prevent the compression plug 4 from loosening during operation, which could lead to insufficient deformation of the dynamic seal and thus leakage.

[0027] Furthermore, the motor outer tube 2 is threadedly connected to the mounting base 12, and a second O-ring 9 is provided at the connection. By providing the second O-ring 9, the sealing of the connection between the motor outer tube 2 and the mounting base 12 is ensured, thereby improving the overall sealing performance of the structure.

[0028] In addition to the preferred embodiments described above, there are other embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection claimed by this utility model.

Claims

1. A high-reliability dynamic seal structure for a propeller shaft, characterized by, The device includes a mounting base (12), a motor outer tube (2), and a motor (1). The mounting base (12) is connected to the motor outer tube (2). The motor (1) is located inside the motor outer tube (2). A transmission shaft (3) is located inside the mounting base (12). The transmission shaft (3) is connected to the output shaft of the motor (1) via a coupling (14). A sealing assembly is installed in the space formed by the transmission shaft (3) and the mounting base (12). The sealing assembly includes a compression plug (4), a first dynamic seal, and a second dynamic seal. The compression plug (4) is located at both ends of the transmission shaft (3). The second dynamic seal is located inside the compression plug (4) near the motor (1), and the first dynamic seal is located inside the compression plug (4) away from the motor (1). Silicone oil is filled between the first dynamic seal and the second dynamic seal.

2. A high reliability dynamic seal for a propeller shaft as claimed in claim 1, wherein, The first dynamic seal of the drive shaft (3) away from the motor (1) consists of at least two dynamic seal rings (8), and a spacer (7) is provided between adjacent dynamic seal rings (8).

3. A high reliability dynamic seal for a propeller shaft as claimed in claim 1, wherein, The second dynamic seal of the drive shaft (3) near the motor (1) is a dynamic seal ring (8), and spacers (7) are provided on both sides of the dynamic seal ring (8).

4. A high reliability dynamic seal for a propeller shaft as claimed in claim 1, wherein, The second dynamic seal is provided with a sealing plug (5) on the outside, and a first O-ring (6) is provided between the sealing plug (5) and the mounting base (12).

5. A high reliability dynamic seal for a propeller shaft as claimed in claim 1, wherein, The drive shaft (3) has a shoulder in the middle, and a thrust bearing (10) and a deep groove ball bearing (11) are respectively provided on both sides of the shoulder.

6. A high reliability dynamic seal for a propeller shaft as claimed in claim 1, wherein, The compression plug (4) is equipped with an anti-loosening screw (13).

7. A high reliability dynamic seal for a propeller shaft as claimed in claim 1, wherein, The motor outer tube (2) is threadedly connected to the mounting base (12), and a second O-ring (9) is provided at the connection.

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