A flap-tooth type universal shaft sealing structure

Abstract

The present application relates to a flap-tooth universal joint sealing structure, which belongs to the technical field of screw drill tools for oil and natural gas drilling. The universal joint includes an intermediate shaft and a universal joint sleeved on the end of the intermediate shaft. A sealing sleeve and a split ring are provided between the intermediate shaft and the universal joint. A sealing sleeve is provided. The sealing sleeve is located on the outside of the sealing sleeve. The sealing sleeve radially clamps the sealing sleeve so that the sealing sleeve and the split ring are sealed. Therefore, in the process of transmitting torque and speed of the universal joint, the motor rotor performs eccentric rotation and generates axial tension on the universal joint, which ultimately acts directly on the sealing sleeve. Due to the axial load-bearing effect of the sealing sleeve, the axial pressure transmitted to the sealing sleeve is significantly reduced, avoiding fatigue damage of the sealing sleeve caused by periodic axial tension, thereby extending the durability of the sealing sleeve and improving the service life of the flap-tooth universal joint.

Description

Technical Field

[0001] The present application relates to the technical field of screw drill tools for oil and natural gas drilling, and in particular to a flap-tooth type universal shaft sealing structure. Background Art

[0002] Screw drills are increasingly used in oil and gas production. These tools consist of a bypass valve assembly, a motor assembly, a universal joint, and a drive shaft assembly. These components are connected sequentially from top to bottom. The upper end of the universal joint is connected to the motor rotor, while the lower end is connected to the drive shaft. The universal joint converts the motor rotor's planetary motion into fixed-axis motion for the drive shaft, smoothly transmitting the motor's torque and speed to the drill bit.

[0003] In the related art, the universal joint of the screw drill is mostly a petal-tooth sealing structure. For example, in the Chinese invention patent CN114562221A published on May 31, 2022, a split ring, a sealing sleeve and a locking nut are provided between the universal joint and the intermediate shaft. One end of the sealing sleeve is clamped between the split ring and the locking nut, and the other end of the sealing sleeve is fitted with the outer wall of the intermediate shaft. A throat clamp is provided on the sealing sleeve to lock the sealing sleeve on the intermediate shaft, thereby realizing the sealing of the universal shaft.

[0004] During drilling, the motor rotor of the screw drill tool rotates eccentrically, exerting axial tension on the upper joint. The upper joint is connected to the motor rotor via a threaded connection, and the upper joint and the lock nut are also threaded, so the lock nut also experiences a certain amount of axial tension.

[0005] As described above, the stepped surfaces of the small end of the lock nut, the large end of the rubber sealing sleeve, and the small end of the split ring achieve axial locking and positioning. The force is transmitted to the stepped surface of the rubber sealing sleeve and manifests as a tensile force, locking the small end of the rubber sealing sleeve by the throat clamp. Therefore, the stress state of the rubber sealing sleeve is that the small end is completely fixed and the large end is subjected to periodic tensile force, which can easily lead to fatigue damage to the rubber sealing sleeve, thereby causing the flap-tooth universal shaft seal structure to fail, further easily causing flap wear, and ultimately reducing the life of the flap-tooth universal shaft. Summary of the Invention

[0006] An embodiment of the present application provides a flap-tooth type universal shaft sealing structure to solve the problem in the related art that the stress state of the sealing sleeve in the universal shaft sealing structure is that the small end is completely fixed and the large end is subjected to periodic tension, which easily causes fatigue damage to the sealing sleeve, resulting in failure of the sealing structure and a reduction in the life of the universal shaft.

[0007] The embodiment of the present application provides a flap-tooth type universal shaft sealing structure, comprising:

[0008] A universal joint, comprising an intermediate shaft and a universal joint sleeved on the end of the intermediate shaft, with a sealing sleeve and a split ring provided between the intermediate shaft and the universal joint;

[0009] A sealing sleeve is located outside the sealing sleeve and radially clamps the sealing sleeve to ensure a sealing connection between the sealing sleeve and the split ring.

[0010] In some embodiments, the sealing sleeve extends axially away from one end of the split ring and wraps around the sealing sleeve, and an expansion space is preset between the sealing sleeve and the sealing sleeve for the sealing sleeve to expand and contract.

[0011] In some embodiments, the diameter of the expansion space in the sealing sleeve gradually decreases in a direction away from the split ring.

[0012] In some embodiments, one end of the sealing sleeve away from the split ring extends axially to the end of the sealing sleeve, and the one end of the sealing sleeve away from the split ring is provided with a positioning surface for axially positioning the sealing sleeve.

[0013] In some embodiments, the outer wall of the sealing sleeve and the inner wall of the universal joint are interference fit, and a sealing ring is provided between the end of the sealing sleeve away from the split ring and the intermediate shaft.

[0014] In some embodiments, one end of the sealing sleeve away from the split ring is fixed to the intermediate shaft via a throat clamp.

[0015] In some embodiments, a pressing surface for radially pressing the throat clamp is provided on the sealing sleeve.

[0016] In some embodiments, an annular groove is provided on the connecting surface of the split ring and the sealing sleeve, and an anti-slip flange that cooperates with the annular groove is provided on the connecting surface of the sealing sleeve and the split ring.

[0017] In some embodiments, a locking nut threadedly connected to the universal joint is further included, and the locking nut is used to axially position the sealing sleeve and the split ring.

[0018] In some embodiments, a first gasket is provided between the locking nut and the universal joint, and a second gasket is provided between the locking nut and the sealing sleeve.

[0019] The beneficial effects of the technical solution provided by this application include:

[0020] An embodiment of the present application provides a petal-toothed universal shaft sealing structure. Since the universal shaft includes an intermediate shaft and a universal joint sleeved on the end of the intermediate shaft, a sealing sleeve and a split ring are arranged between the intermediate shaft and the universal joint; a sealing sleeve, the sealing sleeve is located on the outside of the sealing sleeve, and the sealing sleeve radially clamps the sealing sleeve to ensure a sealing connection between the sealing sleeve and the split ring.

[0021] Therefore, in the process of transmitting torque and speed of the universal joint, the motor rotor performs eccentric rotation and generates axial tension on the universal joint, which ultimately acts directly on the sealing sleeve. Due to the axial load-bearing effect of the sealing sleeve, the axial pressure ultimately transmitted to the sealing sleeve is significantly reduced, avoiding fatigue damage of the sealing sleeve caused by periodic axial tension, thereby extending the durability of the sealing sleeve and improving the service life of the petal-toothed universal joint. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0023] Figure 1 This is a schematic structural diagram of an embodiment of the present application;

[0024] Figure 2 This is a schematic structural diagram of a sealing sleeve according to an embodiment of the present application;

[0025] Figure 3 for Figure 1 Cross-sectional view along the AA direction.

[0026] In the accompanying drawings, the components represented by the reference numerals are as follows:

[0027] 1. Intermediate shaft; 2. Universal joint; 3. Sealing sleeve; 31. Anti-slip flange; 4. Split ring; 41. Annular groove; 5. Sealing sleeve; 51. Expansion space; 52. Positioning surface; 53. Pressing surface; 6. Sealing ring; 7. Hose clamp; 8. Locking nut; 9. First gasket; 10. Second gasket. DETAILED DESCRIPTION

[0028] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0029] The embodiment of the present application provides a flap-tooth type universal shaft sealing structure, which can solve the problem that the stress state of the sealing sleeve in the universal shaft sealing structure in the related technology is that the small end is completely fixed and the large end is subjected to periodic tension, which can easily cause fatigue damage to the sealing sleeve, resulting in failure of the sealing structure and reduced service life of the universal shaft.

[0030] See also Figures 1 to 3 As shown, the embodiment of the present application provides a flap-toothed universal shaft sealing structure, comprising:

[0031] A universal joint comprises an intermediate shaft 1 and a universal joint 2 sleeved on the end of the intermediate shaft 1, with a sealing sleeve 3 and a split ring 4 provided between the intermediate shaft 1 and the universal joint 2;

[0032] The sealing sleeve 5 is located outside the sealing sleeve 3 and radially clamps the sealing sleeve 3 to ensure a sealing connection between the sealing sleeve 3 and the split ring 4 .

[0033] The universal shaft of the petal-tooth universal shaft sealing structure of the embodiment of the present application is provided with an intermediate shaft 1 and a universal joint 2 sleeved on the end of the intermediate shaft 1. A sealing sleeve 3, a split ring 4 and a sealing sleeve 5 are provided between the intermediate shaft 1 and the universal joint 2. The sealing sleeve 5 is located on the outside of the sealing sleeve 3, which facilitates the installation of the split ring 4, the sealing sleeve 3 and the sealing sleeve 5 in sequence. After the sealing sleeve 5 is installed, its inner side radially clamps the end of the sealing sleeve 3 to form a seal between the sealing sleeve 3 and the split ring 4.

[0034] During the drilling process, the motor rotor of the screw drill tool performs eccentric rotation and generates axial tension on the universal joint 2, which ultimately acts directly on the sealing sleeve 5. Due to the axial load-bearing effect of the sealing sleeve 5, the axial pressure ultimately transmitted to the sealing sleeve 3 is significantly reduced, avoiding fatigue damage to the sealing sleeve 3 caused by periodic axial tension, thereby extending the durability of the sealing sleeve 3 and improving the service life of the petal-toothed universal joint.

[0035] It should be noted that the sealing sleeve 5 can be configured as an integral sleeve or a split sleeve according to the actual installation situation. The sealing sleeve can be a rubber tube. An oil filling hole for injecting grease into the universal joint 2 is formed on the side wall of the universal joint 2, and an oil plug is threadedly connected to the oil filling hole.

[0036] In some alternative embodiments: See Figure 2 As shown, an embodiment of the present application provides a flap-tooth type universal shaft sealing structure, in which the sealing sleeve 5 of the flap-tooth type universal shaft sealing structure extends axially away from one end of the split ring 4 and wraps around the sealing sleeve 3, and an expansion space 51 is preset between the sealing sleeve 5 and the sealing sleeve 3 for the sealing sleeve 3 to expand and contract.

[0037] The sealing sleeve 5 of the flap-tooth universal shaft sealing structure of the embodiment of the present application extends axially at one end away from the split ring 4 and wraps around the sealing sleeve 3. An expansion space 51 is preset between the sealing sleeve 5 and the sealing sleeve 3 for the sealing sleeve 3 to expand and contract.

[0038] Because the grease in the inner cavity of the sealing structure is sheared by the high-speed rotating petals at high temperatures, the grease becomes thinner and more fluid, causing it to rotate at high speed within the sealing cavity. This generates a certain amount of hydraulic pressure on the inner cavity of the sealing sleeve 3, causing the sealing sleeve 3 to swell and deform. Therefore, when the sealing sleeve 3 deforms under the action of hydraulic pressure, the radial load-bearing protection of the sealing sleeve 5 prevents excessive swelling and deformation of the sealing sleeve 3, thereby extending its durability and further improving the service life of the petal-toothed universal joint.

[0039] In some alternative embodiments: See Figure 2 As shown, an embodiment of the present application provides a flap-tooth type universal shaft sealing structure, in which the diameter of the expansion space 51 in the sealing sleeve 5 of the flap-tooth type universal shaft sealing structure gradually decreases in the direction away from the split ring 4.

[0040] The diameter of the expansion space 51 in the sealing sleeve 5 of the flap-tooth type universal shaft sealing structure of the embodiment of the present application gradually decreases in the direction away from the split ring 4.

[0041] Because the small end of the sealing sleeve 3 is radially locked, the annular space between this area and the intermediate shaft 1 is smaller, resulting in a higher hydraulic pressure from the grease. This expansion and deformation of this area can more easily lead to excessive stretching and damage of the sealing sleeve 3. By designing the diameter of the expansion space 51 within the sealing sleeve 5 to gradually decrease as it moves away from the split ring 4, the clearance available for expansion of the small end of the sealing sleeve 3 is reduced, thereby preventing damage caused by excessive expansion and stretching.

[0042] In some alternative embodiments: See Figure 2 As shown, an embodiment of the present application provides a flap-tooth type universal shaft sealing structure, in which the sealing sleeve 5 of the flap-tooth type universal shaft sealing structure extends axially to the end of the sealing sleeve 3 at one end away from the split ring 4, and the sealing sleeve 5 is provided with a positioning surface 52 for axially positioning the sealing sleeve 3 at the end away from the split ring 4.

[0043] The sealing sleeve 5 of the flap-tooth universal shaft sealing structure of the embodiment of the present application extends axially to the end of the sealing sleeve 3 at one end away from the split ring 4, and is provided with a positioning surface 52 for axially positioning the sealing sleeve 3 at the other end away from the split ring 4.

[0044] During specific use, the positioning surface 52 of the sealing sleeve 5 can axially limit the position of the small end of the sealing sleeve 3, thereby preventing the small end of the sealing sleeve 3 from being excessively stretched and deformed due to hydraulic displacement.

[0045] In some alternative embodiments: See Figure 2 As shown, an embodiment of the present application provides a flap-tooth type universal shaft sealing structure, in which the outer wall of the sealing sleeve 5 and the inner wall of the universal joint 2 are interference fit, and a sealing ring 6 is arranged between the end of the sealing sleeve 5 away from the split ring 4 and the intermediate shaft 1.

[0046] The outer wall of the sealing sleeve 5 of the flap-tooth type universal shaft sealing structure of the embodiment of the present application is interference fit with the inner wall of the universal joint 2, and a sealing ring 6 is provided between the end of the sealing sleeve 5 away from the split ring 4 and the intermediate shaft 1.

[0047] During specific use, the sealing ring 6, the sealing sleeve 5, the universal joint 2 and the split ring 4 form a sealing structure to protect the sealing sleeve 3, thereby preventing foreign matter such as mud from contacting the sealing sleeve 3 during drilling, thereby ensuring the service life of the sealing sleeve 3.

[0048] It should be noted that those skilled in the art can set the gap between the end of the sealing sleeve 5 away from the split ring 4 and the intermediate shaft 1 according to the actual use of the universal joint, and select a sealing ring 6 of appropriate specifications for installation, so as to meet the requirements of the swing amplitude of the intermediate shaft 1 relative to the universal joint 2 during use.

[0049] In some alternative embodiments: See Figure 2 As shown, an embodiment of the present application provides a flap-tooth type universal shaft sealing structure, in which the end of the sealing sleeve 3 away from the split ring 4 is fixed to the intermediate shaft 1 through a throat clamp 7.

[0050] The end of the sealing sleeve 3 of the flap-tooth universal shaft sealing structure in the embodiment of the present application, which is away from the split ring 4, is in contact with the outer wall of the intermediate shaft 1 and is radially pressed against the intermediate shaft 1 through the throat clamp 7.

[0051] During specific use, the throat clamp 7, the sealing sleeve 3, and the split ring 4 form a sealing structure to prevent the grease in the sealing sleeve 3 from leaking, thereby ensuring good lubricity.

[0052] It should be noted that the sealing structure of the embodiment of the present application is combined with the above-mentioned sealing ring 6, sealing sleeve 5, universal joint 2 and split ring 4 to form a sealing structure, which can achieve a double sealing function and better improve the service life of the petal-toothed universal joint.

[0053] In some alternative embodiments: See Figure 2 As shown, an embodiment of the present application provides a flap-tooth type universal shaft sealing structure, and a pressing surface 53 for radially pressing the throat clamp 7 is provided on the sealing sleeve 5 of the flap-tooth type universal shaft sealing structure.

[0054] The sealing sleeve 5 of the flap-tooth type universal shaft sealing structure of the embodiment of the present application is provided with a pressing surface 53 for radially pressing the throat hoop 7 .

[0055] During specific use, the pressing surface 53 and the outer surface of the throat clamp 7 are rigidly contacted, fitted and pressed together, so that the small end of the sealing sleeve 3 is better fixed.

[0056] In some alternative embodiments: See Figure 2 As shown, an embodiment of the present application provides a flap-tooth type universal shaft sealing structure, in which an annular groove 41 is provided on the connecting surface of the split ring 4 and the sealing sleeve 3 of the flap-tooth type universal shaft sealing structure, and an anti-slip flange 31 cooperating with the annular groove 41 is provided on the connecting surface of the sealing sleeve 3 and the split ring 4.

[0057] An annular groove 41 is provided on the connecting surface of the split ring 4 and the sealing sleeve 3 of the petal-toothed universal shaft sealing structure of the embodiment of the present application, and an anti-slip flange 31 cooperating with the annular groove 41 is provided on the connecting surface of the sealing sleeve 3 and the split ring 4.

[0058] Since the sealing sleeve 3 is usually made of rubber, which is an elastomer, the swinging and up and down movement of the universal joint during use may cause the sealing sleeve 3 to slip. Therefore, an anti-slip flange 31 is provided on the sealing sleeve 3, and the anti-slip flange 31 is extended into the annular groove 41 on the split ring 4, which can prevent the large end of the sealing sleeve 3 from slipping and ensure the stable use of the sealing sleeve 3.

[0059] In some alternative embodiments: See Figure 1 and 2 As shown, an embodiment of the present application provides a flap-tooth type universal shaft sealing structure, which also includes a locking nut 8 threadedly connected to the universal joint 2, and the locking nut 8 is used to axially position the sealing sleeve 5 and the split ring 4.

[0060] The flap-toothed universal shaft sealing structure of the embodiment of the present application further includes a locking nut 8 threadedly connected to the universal joint 2 , and the locking nut 8 is used for axial positioning of the sealing sleeve 5 and the split ring 4 .

[0061] During specific use, the locking nut 8 is installed on the universal joint 2 , the locking nut 8 presses against the sealing sleeve 5 , and the sealing sleeve 5 presses against the split ring 4 , thereby axially fixing the sealing sleeve 5 and the split ring 4 .

[0062] It should be noted that the sealing sleeve 5 can be composed of two completely symmetrical semi-annular structures, and the split ring 4 can also be composed of two completely symmetrical semi-annular structures, thereby achieving convenient installation.

[0063] In some alternative embodiments: See Figure 2As shown, an embodiment of the present application provides a flap-tooth type universal shaft sealing structure, in which a first gasket 9 is arranged between the locking nut 8 and the universal joint 2, and a second gasket 10 is arranged between the locking nut 8 and the sealing sleeve 5.

[0064] A first gasket 9 is provided between the locking nut 8 and the universal joint 2 of the flap-tooth type universal shaft sealing structure of the embodiment of the present application, and a second gasket 10 is provided between the locking nut 8 and the sealing sleeve 5.

[0065] During specific use, the first gasket 9 fills the gap between the locking nut 8 and the universal joint 2, and the second gasket 10 fills the gap between the locking nut 8 and the sealing sleeve 5, which can ensure the stability of the locking nut 8 after installation and prevent the sealing sleeve 5 from loosening.

[0066] In the description of this application, it should be noted that the terms "upper" and "lower" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0067] It should be noted that, in this application, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0068] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. A flap-tooth type universal shaft sealing structure, characterized in that: include: A universal joint, comprising an intermediate shaft (1) and a universal joint (2) sleeved on an end of the intermediate shaft (1), a sealing sleeve (3) and a split ring (4) being provided between the intermediate shaft (1) and the universal joint (2); A sealing sleeve (5), the sealing sleeve (5) being located outside the sealing sleeve (3), the sealing sleeve (5) radially clamping the sealing sleeve (3) so as to seal the sealing sleeve (3) and the split ring (4); One end of the sealing sleeve (5) away from the split ring (4) extends axially and wraps around the sealing sleeve (3); an expansion space (51) for the sealing sleeve (3) to expand and contract is preset between the sealing sleeve (5) and the sealing sleeve (3); The diameter of the expansion space (51) in the sealing sleeve (5) gradually decreases in a direction away from the split ring (4); One end of the sealing sleeve (5) away from the split ring (4) extends axially to the end of the sealing sleeve (3), and one end of the sealing sleeve (5) away from the split ring (4) is provided with a positioning surface (52) for axially positioning the sealing sleeve (3).

2. The flap-tooth type universal shaft seal structure according to claim 1, characterized in that: The outer wall of the sealing sleeve (5) and the inner wall of the universal joint (2) are interference-fitted, and a sealing ring (6) is provided between the end of the sealing sleeve (5) away from the split ring (4) and the intermediate shaft (1).

3. The flap-tooth type universal shaft seal structure according to claim 1, characterized in that: One end of the sealing sleeve (3) away from the split ring (4) is fixed to the intermediate shaft (1) via a throat hoop (7).

4. The flap-tooth type universal shaft seal structure according to claim 3, characterized in that: The sealing sleeve (5) is provided with a pressing surface (53) for radially pressing the throat clamp (7).

5. The flap-tooth type universal shaft seal structure according to claim 1, characterized in that: An annular groove (41) is provided on the connection surface between the split ring (4) and the sealing sleeve (3), and an anti-slip flange (31) that cooperates with the annular groove (41) is provided on the connection surface between the sealing sleeve (3) and the split ring (4).

6. The flap-tooth type universal shaft seal structure according to claim 1, characterized in that: It also includes a locking nut (8) threadedly connected to the universal joint (2), and the locking nut (8) is used to axially position the sealing sleeve (5) and the split ring (4).

7. The flap-tooth type universal shaft seal structure according to claim 6, characterized in that: A first gasket (9) is provided between the locking nut (8) and the universal joint (2), and a second gasket (10) is provided between the locking nut (8) and the sealing sleeve (5).

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