Anti-vibration traction section of underground tractor

Abstract

The utility model discloses an anti-vibration traction section of an underground tractor. The anti-vibration traction section solves the problems that a sealing ring on the periphery of a transmission shaft is abraded and fractured and dynamic sealing fails due to vibration of an existing traction section. According to the technical scheme, the traction device comprises a mechanical system, a traction wheel driving assembly and a power system which are sequentially connected, the power system is installed in a shell and comprises a traction motor, a speed reducer and a transmission shaft which are connected, and an output shaft of the speed reducer is connected with the traction wheel driving assembly outside the shell through the transmission shaft; bearings located at the opening of the shell are arranged at the two ends of the transmission shaft, the outer side bearing is a sealed bearing, and the inner side bearing is a linear bearing; and at least one sealing ring is arranged on the periphery of the transmission shaft between the two bearings. The utility model has the advantages of extremely simple structure, good sealing effect and good stability, effectively reduces the vibration of the transmission shaft, improves the heat exchange cooling rate in the shell, and prolongs the service life of equipment.

Description

Technical Field

[0001] This utility model relates to a traction device structure, specifically the vibration-damping traction section of a downhole traction device. Background Technology

[0002] In recent years, the number of high-temperature oil and gas wells in China has been increasing, and the requirements for traction device sealing technology have become increasingly stringent. They must not only withstand high pressure, high temperature, high linear velocity, and large dynamic loads of the medium, but also maintain a seal for extended periods.

[0003] The traction device consists of 2 to 4 traction sections connected in series. Each traction section comprises three parts: a mechanical system, a traction wheel drive system, and a power system. The power system is the key component of the actuator that powers the traction device. It is sealed and installed in a housing and filled with hydraulic oil containing a heat-conducting medium.

[0004] The traction motor inside the power system typically rotates at a high speed of 3000-5000 rpm, transmitting kinetic energy sequentially through a reducer and drive shaft to the traction wheel drive assembly. This causes the traction wheel on the drive assembly to rotate and move the instrument. For example, CN204002562U discloses a turbine-driven horizontal well casing traction device used to lower casing to a predetermined position in a horizontal well. Its structural feature is the use of a turbine as the drive mechanism, which consists of a stator and a rotor; the stator is pressed together with the housing, and the rotor is connected to the drive shaft via a key. In the prior art, the drive shaft is led out from the sealed housing and connected to the traction wheel drive assembly. Due to the relatively long length of the drive shaft, prolonged high-speed rotation can cause vibration that leads to wear and breakage of the seals on the outer periphery of the drive shaft, resulting in dynamic seal failure and inoperability. For example, CN215720295U discloses a self-lubricating drive shaft assembly, in which the upper drive shaft is located between the upper and lower housings, the upper TC stationary sleeve is disposed between the lower housing and the upper drive shaft, the lower TC stationary sleeve is disposed outside the lower drive shaft, and one end of the lower TC stationary sleeve is inserted into and mates with the lower housing, while one end of the lower drive shaft is inserted into and mates with the tail end of the upper drive shaft. This solution is mainly designed for drilling operations without lubrication and does not address the wear and sealing problems caused by vibration of long drive shafts. Summary of the Invention

[0005] The purpose of this utility model is to solve the above-mentioned technical problems and provide a vibration-damping traction section for a downhole traction device that has an extremely simple structure, good sealing effect, good stability, effectively reduces the vibration of the drive shaft, improves the heat exchange and cooling rate inside the housing, and improves the service life of the equipment.

[0006] The technical solution includes a mechanical system, a traction wheel drive assembly, and a power system connected in sequence. The power system is installed inside the housing and includes a traction motor, a reducer, and a drive shaft. The output shaft of the reducer is connected to the traction wheel drive assembly outside the housing via the drive shaft. Bearings located at the opening of the housing are fitted on both sides of the drive shaft, wherein the outer bearing is a sealed bearing and the inner bearing is a linear bearing. At least one sealing ring is provided at the housing opening on the outer periphery of the drive shaft between the two bearings.

[0007] The two ends of the drive shaft are respectively connected to the reducer and the traction wheel drive assembly via keys.

[0008] The two ends of the drive shaft are respectively connected to the reducer and the traction wheel drive assembly via splines or flat keys.

[0009] The distance between the bearings on both sides of the drive shaft is one-third of the total length of the drive shaft.

[0010] The outer diameter of the drive shaft and the inner diameter of the bearing inner ring are fitted with a transition fit.

[0011] To address the issues of long drive shafts and lack of effective support in existing systems, bearings are installed at both ends of the drive shaft. These bearings support the drive shaft, providing shock absorption and preventing wear and breakage of the outer seals caused by vibration, thus extending the service life of components. Two bearings are fixed one after the other at the opening of the housing. At least one seal is installed on the outer circumference of the drive shaft between the two bearings for sealing. Considering the needs of housing sealing and heat exchange, the outer bearing (closer to the traction wheel drive assembly) is a sealed bearing. This type of bearing has a sealing function, preventing impurities in the well from affecting the sealing effect of the seals, further improving sealing performance. The inner bearing is a linear bearing. This bearing is closer to the reducer and does not require a sealing function. In addition to supporting the drive shaft, the rotation of the inner ring of the linear bearing creates localized swirling flow due to the heat exchange medium filled in the housing. This drives the flow of liquid phase within the housing, allowing heat-generating components such as the traction motor to release heat quickly, improving heat exchange efficiency and further extending the equipment's service life—a multi-benefit approach.

[0012] This utility model has an extremely simple structure, good sealing effect, good stability, effectively reduces the vibration of the transmission shaft, improves the heat exchange and cooling rate inside the shell, and extends the service life of the equipment. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of this utility model.

[0014] Figure 2 This is a partial sectional view of the drive shaft.

[0015] Among them, 1. Traction motor, 2. Reducer, 3. Key, 4. Drive shaft, 5. Outer bearing, 6. Traction wheel drive assembly, 7. Sealing ring, 8. Mechanical system, 9. Power system, 10. Housing, 11. Inner bearing, 12. Keyway. Detailed Implementation

[0016] The present invention will be further explained below with reference to the accompanying drawings:

[0017] See Figure 1 The anti-vibration traction section of this utility model consists of a mechanical system 8, a traction wheel drive assembly 6, and a power system 9 connected in sequence. The power system 8 is installed inside the housing 10 and includes a traction motor 1, a reducer 2, and a drive shaft 4. The output shaft of the reducer 2 is provided with a key 3, and one end of the drive shaft 4 is provided with a corresponding keyway 12. The two are connected by a key (preferably a spline connection). The other end of the drive shaft 4 is also splined to the traction wheel drive assembly 6 outside the housing 10.

[0018] The drive shaft 4 has bearings at both ends located at the openings of the housing 10. At least one sealing ring 7 (two sealing rings in this embodiment) is provided on the outside of the drive shaft 4 between the two bearings, forming a seal at the opening of the housing 10 to prevent leakage and intrusion of fluid media. The bearings at both ends of the drive shaft 4 are symmetrically arranged with the midpoint of the drive shaft 4 as the center, and the distance between them is one-third of the total length of the drive shaft 4. If the distance is too short, the high-speed rotation of the drive shaft will cause significant vibration of the journal, and in severe cases, it may even cause key breakage. If the distance is too long, the center of mass of the high-speed rotating drive shaft will shift from the rotation center line, causing vibration in the middle, and over time, slight bending deformation will occur, causing an imbalance of force on the sealing ring, accelerating the damage of the sealing ring, and causing dynamic seal failure. It is best to use a transition fit between the outer diameter of the drive shaft 4 and the inner diameter of the bearing's inner ring; wherein, the outer bearing 5 is a sealed bearing, and the inner bearing 11 is a linear bearing.

[0019] Compared with the traditional bearingless traction section of the drive shaft, the structure of this utility model can effectively reduce the vibration of the drive shaft when rotating at high speed, protect the sealing ring, ensure good dynamic sealing effect over a long period of time, and improve the heat exchange efficiency between the heating device motor and the outside environment.

Claims

1. A vibration-damping traction section for a downhole traction device, comprising a mechanical system, a traction wheel drive assembly, and a power system connected in sequence, characterized in that, The power system is installed inside the housing and includes a connected traction motor, a reducer, and a drive shaft. The output shaft of the reducer is connected to the traction wheel drive assembly outside the housing via the drive shaft. Bearings located at the opening of the housing are fitted on both sides of the drive shaft, wherein the outer bearing is a sealed bearing and the inner bearing is a linear bearing. At least one sealing ring is provided at the housing opening on the outer periphery of the drive shaft between the two bearings.

2. The vibration-damping traction section of the traction device as described in claim 1, characterized in that, The two sides of the drive shaft are respectively connected to the reducer and the traction wheel drive assembly via keys.

3. The vibration-damping traction section of the traction device as described in claim 2, characterized in that, The two sides of the drive shaft are respectively connected to the reducer and the traction wheel drive assembly via splines or flat keys.

4. The vibration-damping traction section of the downhole traction device as described in any one of claims 1-3, characterized in that, The distance between the bearings on both sides of the drive shaft is one-third of the total length of the drive shaft.

5. The vibration-damping traction section of the downhole traction device as described in any one of claims 1-3, characterized in that, The outer diameter of the drive shaft and the inner diameter of the bearing inner ring are fitted with a transition fit.

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