A rotary joint and a drilling rig

Abstract

The application discloses a rotary joint and a drilling machine, and the rotary joint comprises a rotating shaft, a bearing, a limiting shell, a packing seal box assembly, a wear-resistant mandrel body, a flange assembly and a mud input joint; the rotating shaft is rotatably installed in the limiting shell through the bearing which is axially limited; the first end part of the wear-resistant mandrel body is located in the rotating shaft, and the outer ring of the first end part of the wear-resistant mandrel body and the inner ring of the rotating shaft are rotatably sealed through the packing seal box assembly, and the packing seal box assembly is axially and circumferentially limited relative to the rotating shaft; the second end part of the wear-resistant mandrel body is connected with the mud input joint through the packing assembly in a static sealing mode; the flange assembly comprises a first flange, a flange connecting part and a second flange which are sequentially connected, the first flange is fixedly connected with the limiting shell, the second flange is fixedly connected with the mud input joint, and the wear-resistant mandrel body is axially adjustably connected with the flange connecting part through a connecting piece. The sealing effect is guaranteed, and the service life of the rotary joint is improved.

Description

Technical Field

[0001] This invention belongs to the field of trenchless product technology, specifically relating to a rotary joint and drilling rig, and more specifically to a trenchless rotary joint and drilling rig based on oil tap flushing and sealing technology. Background Technology

[0002] In horizontal directional drilling rigs or inclined shaft drilling rigs used in related technologies, the fixing bolts of the pressure ring in ordinary rotary joints are not pre-tightened during installation. The bolts are tightened only to flatten the washer, without being fully tightened. This leads to the pressure ring bolts gradually loosening under vibration during rotation, while the right flange cover does not rotate. Consequently, the pressure ring bolts are gradually worn down by the right flange cover during rotation. Simultaneously, because the bolts are not properly secured, the pressure ring experiences uneven stress on the sealing ring, leading to unavoidable wear. This affects the overall structural sealing performance, reduces its service life, increases costs, and requires frequent maintenance, further increasing labor costs. Summary of the Invention

[0003] Objective: In view of at least one of the above technical problems, the present invention provides a rotary joint and drilling rig, which, based on the oil tap flushing sealing technology, ensures sealing effect, improves service life, and reduces operating costs.

[0004] Technical solution: To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0005] In a first aspect, the present invention provides a rotary joint, comprising a rotary shaft, a bearing, a limiting housing, a packing seal box assembly, a wear-resistant mandrel, a flange assembly, and a mud inlet joint;

[0006] The rotating shaft is rotatably mounted in the limiting housing via an axially limited bearing;

[0007] The first end of the wear-resistant mandrel is located inside the rotating shaft, and the outer ring of the first end of the wear-resistant mandrel and the inner ring of the rotating shaft are rotated and sealed by a packing seal box assembly, and the packing seal box assembly is limited in the axial and circumferential directions relative to the rotating shaft.

[0008] The second end of the wear-resistant mandrel is statically sealed to the mud input connector via a packing assembly.

[0009] The flange assembly includes a first flange, a flange connection part, and a second flange connected in sequence. The first flange is fixedly connected to the limiting housing, and the second flange is fixedly connected to the mud input joint. The wear-resistant mandrel is axially adjustable to the flange connection part through a connector.

[0010] In some embodiments, the packing seal box assembly includes a packing box, a packing seal assembly, a seal box spacer, and a sand-blocking device. The packing seal assembly is installed on the inner ring of the packing box. The packing seal assembly includes multiple sets of first packing seals, and adjacent first packing seals are separated by spacer rings. The seal box spacer is installed at the first end of the packing box. The end of the seal box spacer near the packing seal assembly presses against the packing seal assembly, and the axial position of the packing box relative to the seal box spacer is adjustable. A sand-blocking device is installed inside the seal box spacer for filtering coarse sand particles during construction.

[0011] In this embodiment, the sealing box spacer is provided with an elongated groove / elongated hole with its length along the axial direction. The sealing box spacer is connected to the packing box by screws passing through the screw holes on the packing box and the elongated groove / elongated hole on the sealing box spacer. The screws can move axially along the elongated groove / elongated hole, thereby making the axial position of the packing box relative to the sealing box spacer adjustable, and adjusting the sealing compression and pre-tightening of the packing seal in the packing sealing box assembly.

[0012] In some embodiments, the rotating shaft is provided with a rotating shaft oil cup, and a lubricating oil passage connected to the rotating shaft oil cup is arranged in the spacer ring of the rotating shaft and the packing seal box assembly. The oil entering through the rotating shaft oil cup can cool and lubricate the first packing seal in the packing box according to the direction of the lubricating oil passage, and at the same time, it can dislodge mud and sand particles from the lip of the first packing seal and the outer ring of the wear-resistant mandrel, thereby extending the service life of the first packing seal.

[0013] In some embodiments, the rotary joint further includes a limiting block for axially and circumferentially limiting the second end of the packing seal box assembly. The inner ring of the second end of the rotary shaft is provided with an anti-rotation groove for circumferentially limiting the installation of the limiting block. The first end of the packing seal box assembly is axially limited and installed in the rotary shaft through a first limiting slot. Under the axial and circumferential limiting action of the rotary shaft and the limiting block, the packing seal box assembly does not have axial or circumferential movement.

[0014] In this embodiment, the limiting block is stepped, and its circumferential width is the same as the anti-rotation groove width; the outer side of the second end of the packing seal box assembly is provided with a second limiting groove that matches the stepped shape of the limiting block. The second end of the packing seal box assembly is axially and circumferentially limited by the engagement of the limiting block and the second limiting groove.

[0015] Furthermore, a sealing ring is installed between the outer ring of the sealing box spacer and the inner ring of the rotating shaft.

[0016] In some embodiments, a bushing is provided at the second end of the packing seal box assembly, a trapezoidal thread is provided on the outer ring of the second end of the rotating shaft, and a matching trapezoidal thread is provided on the inner ring of the packing box cover and the round nut. The packing box cover and the round nut are threadedly connected to the rotating shaft, and the inner side of the packing box cover contacts the bushing. The compression amount and pre-tightening of the packing seal inside the packing seal box assembly can be adjusted by rotating the packing box cover and the round nut to press the bushing.

[0017] In some embodiments, the flange connection portion is provided with multiple sets of limiting holes for connecting to the wear-resistant mandrel at different axial positions. The wear-resistant mandrel is connected to the limiting holes of the flange connection portion through a connector, which can adjust the axial position of the wear-resistant mandrel, thereby changing the contact position between the wear-resistant mandrel and the first packing seal lip in the packing seal box assembly.

[0018] In some embodiments, the packing assembly includes a second packing seal and a packing clamping plate. The connection portion of the slurry input connector is provided with an installation groove for installing the second packing seal. The second packing seal is installed in the installation groove and is axially limited and pressed by the packing clamping plate.

[0019] In some embodiments, the limiting housing is provided with a limiting housing oil cup that communicates with the bearing located inside the limiting housing, for entering oil through the limiting housing oil cup to cool and lubricate the bearing.

[0020] In some embodiments, the first end of the bearing is axially limited by a flange cover, and the second end of the bearing is axially limited by a first flange of the flange assembly.

[0021] In some embodiments, a first groove is formed on the flange cover facing the bearing, and a dustproof ring 1 is installed in the first groove; a second groove is formed on the first flange facing the bearing, and a dustproof ring 2 is installed in the second groove. The inner rings of the dustproof ring 1 and the dustproof ring 2 are tightly attached to the outer surface of the rotating shaft to prevent dust and mud from entering the bearing and avoid causing the bearing to seize.

[0022] In a second aspect, the present invention provides a drilling rig including the rotary joint described in the first aspect.

[0023] Beneficial Effects: The rotary joint and drilling rig provided by this invention have the following advantages: Based on the oil tap flushing sealing technology, this invention adds lubricating oil channels and sand-blocking devices, and innovatively proposes a wear compensation mechanism for the wear-resistant mandrel. Simultaneously, it simplifies the wear-resistant mandrel limiting structure, reduces processing steps, and lowers processing complexity. This ensures a good sealing effect, while also extending the service life of the rotary joint and reducing failure feedback. It is currently in mass production, and in actual construction, its service life is 2.7-10 times that of the original. Attached Figure Description

[0024] Figure 1 This is a cross-sectional schematic diagram of the rotary joint in this embodiment;

[0025] Figure 2 This is a cross-sectional view of the packing box assembly in this embodiment;

[0026] Figure 3 This is a schematic diagram of the arrangement of the rotating shaft oil cup and lubrication oil passage in this embodiment;

[0027] Figure 4 This is a schematic diagram of the arrangement of the rotating shaft oil cup and lubrication oil passage in this embodiment;

[0028] Figure 5 This is a schematic diagram of the flange assembly structure in this embodiment;

[0029] Reference numerals: Rotating shaft 1: O-ring 101, anti-rotation groove 102, rotating shaft oil cup 103, lubrication oil passage 104; Flange cover 2, dustproof ring 1 201, bearing 3, limiting housing 4, limiting housing oil cup 401, packing seal box assembly 5: first packing seal 501, sealing ring 5A, packing box 5B, spacer ring 1 5C, spacer ring 2 5D, screw 5E, sand-blocking device 5F, sealing box spacer sleeve 5G; limiting block 6 Part 1 61, Part 1 62, Wear-resistant mandrel 7, Flange assembly 8: First flange 801, Dustproof ring 2 8011, Flange connection 802, Limiting hole 8021, Second flange 803, Mud input connector 9, Second packing seal 10, Packing pressure plate 11, Packing box cover 12, Bushing 13, Round nut 14, Retaining ring 15, Pressure ring 16, Sleeve 17, Retaining ring 18, Bolt 19, Nut 20. Detailed Implementation

[0030] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0031] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0032] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0033] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art will understand the specific meaning of the above terms in this application based on the specific circumstances.

[0034] Example 1: As Figures 1 to 5 As shown, this embodiment provides a rotary joint, including a rotary shaft 1, a bearing 3, a limiting housing 4, a packing seal box assembly 5, a wear-resistant mandrel 7, a flange assembly 8, and a mud input connector 9;

[0035] The first end of the rotating shaft 1 is used to connect with the main shaft of the power head. The rotating shaft 1 is rotatably installed in the limiting housing 4 through the axially limiting bearing 3.

[0036] The first end of the wear-resistant mandrel 7 is located inside the rotating shaft 1, and the outer ring of the first end of the wear-resistant mandrel 7 and the inner ring of the rotating shaft 1 are rotated and sealed by the packing seal box assembly 5, and the packing seal box assembly 5 is axially and circumferentially limited relative to the rotating shaft 1.

[0037] The second end of the wear-resistant mandrel 7 is statically sealed to the mud input joint 9 through a packing assembly (second packing seal 10 and packing pressure plate 11);

[0038] The flange assembly 8 includes a first flange 801, a flange connection part 802, and a second flange 803 connected in sequence. The first flange 801 is fixedly connected to the limiting housing 4 (at one end near the flange assembly), and the second flange 803 is fixedly connected to the mud input connector 9. The wear-resistant mandrel 7 is axially adjustable to the flange connection part 802 through a connector.

[0039] In this embodiment, an O-ring 101 is installed in the groove of the outer ring of the first end of the rotating shaft 1 to achieve a seal between the outer ring of the first end of the rotating shaft 1 and the inner ring of the power head spindle.

[0040] like Figure 2 As shown, the packing box assembly 5 includes a packing box 5B, a packing sealing component, a sealing box spacer 5G, and a sand-blocking device 5F. The packing box 5B has a packing sealing component installed on its inner ring. This component includes multiple sets of first packing seals 501, with adjacent first packing seals 501 separated by spacer rings. The sealing box spacer 5G is installed at the first end of the packing box 5B, pressing the packing sealing component against its end near the sealing box spacer 5G. The axial position of the packing box 5B relative to the sealing box spacer 5G is adjustable. A sand-blocking device 5F is installed inside the sealing box spacer 5G to filter coarse sand particles during construction. By using the sand-blocking device 5F, the filtered slurry containing fine sand particles passes through the packing sealing component. The lips of the three sets of first packing seals 501 contact the outer ring of the wear-resistant mandrel 7, forming a sealing area to prevent slurry leakage.

[0041] In this embodiment, the packing seal assembly includes three sets of first packing seals 501. The three sets of first packing seals 501 are separated by spacer ring 1 5C and spacer ring 2 5D, and then the leftmost first packing seal is pressed by the sealing box spacer sleeve 5G.

[0042] In some embodiments, the sealing box spacer 5G has an elongated groove / elongated hole with its length arranged along the axial direction. The sealing box spacer 5G is connected to the packing box 5B by a screw 5E passing through a screw hole on the packing box 5B and the elongated groove / elongated hole on the sealing box spacer 5G. Since the screw 5E can move axially along the elongated groove / elongated hole, the axial position of the packing box 5B relative to the sealing box spacer 5G can be adjusted, thereby adjusting the sealing compression and pre-tightening of the packing seal inside the packing sealing box assembly 5.

[0043] In some embodiments, a sealing ring 5A is installed in the groove of the outer ring of the sealing box spacer 5G to achieve a seal between the outer ring of the sealing box spacer 5G and the inner ring of the rotating shaft 1.

[0044] In some embodiments, the rotating shaft 1 is provided with a rotating shaft oil cup 103, and a lubricating oil passage 104 connected to the rotating shaft oil cup 103 is arranged in the spacer ring of the rotating shaft 1 and the packing seal box assembly 5. The oil entering through the rotating shaft oil cup 103 can cool and lubricate the first packing seal 501 in the packing box 5B according to the direction of the lubricating oil passage, and at the same time, it can knock out the mud and sand particles in the lip of the first packing seal 501 and the outer ring of the wear-resistant mandrel 7, thereby extending the service life of the first packing seal 501.

[0045] It should be noted that in this embodiment, the lubricating oil passages in the spacer ring are arranged radially, which facilitates the direct entry of oil through the lubricating oil passages into the contact position between the packing seal assembly 5 and the outer ring of the wear-resistant mandrel 7. In addition, at least one spacer ring is provided with a lubricating oil passage communicating with the rotating shaft oil cup 103, or all spacer rings may be provided with lubricating oil passages communicating with the rotating shaft oil cup 103.

[0046] In some embodiments, the rotary joint further includes a limiting block 6 for axially and circumferentially limiting the second end of the packing seal box assembly 5. The inner ring of the second end of the rotary shaft 1 is provided with an anti-rotation groove 102 for installing the limiting block 6. The first end of the packing seal box assembly 5 is axially limited and installed in the rotary shaft 1 through the first limiting slot of the seal box spacer 5G. Under the axial and circumferential limiting action of the rotary shaft 1 and the limiting block 6, the packing seal box assembly 5 does not have axial or circumferential movement.

[0047] In this embodiment, the limiting block 6 is stepped, with a circumferential width the same as the width of the anti-rotation groove 102. Further, the limiting block 6 includes a first part 61 and a first part 62 connected perpendicularly to each other, wherein the first part 61 is arranged axially and the first part 62 is arranged radially (e.g., ...). Figure 1 As shown), by matching the circumferential width of the first part 61 with the circumferential width of the anti-rotation groove 102, the limiting block 6 is circumferentially limited in the anti-rotation groove 102, so the packing seal box assembly 5 does not have circumferential movement relative to the rotating shaft 1.

[0048] The outer side of the second end of the packing seal box assembly 5 is provided with a second limiting groove that matches the stepped shape of the limiting block 6. The second end of the packing seal box assembly 5 is axially and circumferentially limited by the engagement of the limiting block 6 with the second limiting groove.

[0049] Furthermore, since the axial length of the anti-rotation groove 102 is greater than the axial length of the limiting block 6, the limiting block 6 can be used in conjunction with other axial pre-tightening components (such as bushing 13) to make axial adjustments within the anti-rotation groove 102.

[0050] In some embodiments, a bushing 13 is provided at the second end of the packing seal box assembly 5, and a trapezoidal thread is provided on the outer ring of the second end of the rotating shaft 1. The inner rings of the packing box cover 12 and the round nut 14 are provided with matching trapezoidal threads. The packing box cover 12 and the round nut 14 are threadedly connected to the rotating shaft 1, and the inner side of the packing box cover 12 contacts the bushing 13. The compression amount and pre-tightening of the packing seal inside the packing seal box assembly 5 can be adjusted by rotating the packing box cover 12 and the round nut 14 to press the bushing 13. Furthermore, the contact ends of the round nut 14 and the cover 12 achieve self-locking through mutual friction.

[0051] In some embodiments, the flange connection 802 is provided with multiple sets of limiting holes 8021 for connecting to the wear-resistant mandrel 7 at different axial positions. The wear-resistant mandrel 7 is connected to the limiting holes 8021 of the flange connection 802 through a connector, which can adjust the axial position of the wear-resistant mandrel 7, thereby changing the contact position between the wear-resistant mandrel 7 and the lip of the first packing seal 501 in the packing seal box assembly 5.

[0052] In this embodiment, as Figure 5 As shown, the flange connection part 802 of the flange assembly 8 has three sets of limiting holes. The wear-resistant mandrel 7 is connected to the flange connection part 802 of the flange assembly 8 through a set of bolts 19 and nuts 20. By default, the rightmost limiting hole is used first. According to the wear condition, the middle and leftmost limiting holes are used in turn to realize the movement of the wear-resistant mandrel in the direction of the rotating shaft 1, change the contact surface between the first packing seal 501 and the wear-resistant mandrel 7, and increase the life of the wear-resistant mandrel by 3 times. The three sets of limiting holes on the flange connection part 802 are diagonally 180°, and the wear-resistant mandrel is in contact with the lip of the first packing seal 501. It can float axially through the elastic packing seal to ensure uniform seal wear.

[0053] In some embodiments, the packing assembly includes a second packing seal 10 and a packing pressure plate 11. The connection portion of the mud input connector 9 is provided with an installation groove for installing the second packing seal 10. The second packing seal 10 is installed in the installation groove and is axially limited and pressed by the packing pressure plate 11.

[0054] In some embodiments, such as Figure 1 As shown, the limiting housing 4 is provided with a limiting housing oil cup 401 that communicates with the bearing located inside the limiting housing 4, and is used to enter the oil through the limiting housing oil cup 401 to cool and lubricate the bearing 3.

[0055] In some embodiments, such as Figure 1 As shown, the first end of the bearing 3 is axially limited by the flange cover 2, and the second end of the bearing 3 is axially limited by the first flange 801 of the flange assembly 8.

[0056] In this embodiment, a limiting component is further provided between the second end of the bearing 3 and the first flange 801 of the flange assembly 8. The limiting component includes a retaining ring 18, a pressure ring 16, a retaining ring 15, and a sleeve 17. The retaining ring 18 and the retaining ring 15 are respectively installed in corresponding mounting grooves on the outer ring of the rotating shaft 1. The retaining ring 18 is used to limit the inner side of the second end of the bearing 3. The pressure ring 16 is located between the retaining ring 18 and the retaining ring 15, and the pressure ring 16 presses against the retaining ring 18 through a stepped structure that cooperates with the retaining ring 18, preventing the pressure ring 16 from radially moving and falling off. The sleeve 17 is used to limit the outer side of the second end of the bearing 3. In this embodiment, the retaining ring 18 consists of two concentrically arranged arc rings for easy removal.

[0057] In some embodiments, a first groove is formed on the flange cover 2 facing the bearing 3, and a dustproof ring 201 is installed in the first groove; a second groove is formed on the first flange 801 facing the bearing 3, and a dustproof ring 8011 is installed in the second groove. The inner rings of the dustproof ring 201 and the dustproof ring 8011 are tightly attached to the outer surface of the rotating shaft 1 to prevent dust and mud from entering the bearing 3 and avoid causing the bearing to seize.

[0058] A rotary joint according to an embodiment of this application can be adjusted to ensure the rotational sealing performance of the packing seal box assembly 5 through three measures. The first measure: when the first packing seal 501 in the packing seal box assembly 5 becomes loose due to wear, the compression of the packing seal within the packing seal box assembly 5 can be adjusted by rotating the packing box cover 12 and the round nut 14 to tighten the bushing 13, thereby securing the first packing seal 501. The second measure: when the first packing seal 501 in the packing seal box assembly 5 is excessively worn, and adjusting by rotating the packing box cover 12 and the round nut 14 to tighten the bushing 13 still fails to achieve a sealing effect, the packing seal box assembly 5 can be disassembled, and the first packing seal 501 can be replaced. The third measure: If replacing the first packing seal 501 in the packing seal box assembly 5 still fails to achieve a sealing effect, it indicates that the surface of the wear-resistant mandrel 7 in contact with the lip of the first packing seal 501 is severely worn. In this case, by changing the limiting hole 8021 of the flange connection 802 connected to the wear-resistant mandrel 7, the axial position of the packing box 5B relative to the sealing box spacer 5G is adjusted, thereby adjusting the contact position between the lip of the first packing seal 501 and the wear-resistant mandrel 7. In this embodiment, the limiting hole 8021 is provided with three limiting holes based on the sealing contact area and size, which can adjust the axial position of the wear-resistant mandrel 7 three times, thereby increasing the lifespan of the individual mandrel by three times.

[0059] In summary, this application, based on the oil tap flushing sealing technology, innovatively proposes a wear compensation mechanism for the wear-resistant mandrel by adding lubrication channels and sand-blocking devices. Simultaneously, it simplifies the wear-resistant mandrel limiting structure, reduces processing steps, and lowers processing complexity. This ensures a good sealing effect, extends the service life of the rotary joint, and reduces rotary joint failure feedback. It is currently in mass production, and in actual construction, its service life is 2.7-10 times that of the original.

[0060] Example 2: This example provides a drilling rig, including the rotary joint described in any one of Examples 1.

[0061] Furthermore, the drilling rig can be a trenchless product such as a horizontal directional drilling rig or an inclined shaft drilling rig.

[0062] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used to explain the relative positional relationship and movement between components in a specific orientation. If the specific orientation changes, the directional indication will also change accordingly. These terms are used only for the convenience of describing this application and for simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0063] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A rotary joint, characterized in that, Includes a rotating shaft, bearings, limit housing, packing seal box assembly, wear-resistant mandrel, flange assembly, and mud inlet connector; The rotating shaft is rotatably mounted in the limiting housing via an axially limited bearing; The first end of the wear-resistant mandrel is located inside the rotating shaft, and the outer ring of the first end of the wear-resistant mandrel and the inner ring of the rotating shaft are rotated and sealed by a packing seal box assembly, and the packing seal box assembly is limited in the axial and circumferential directions relative to the rotating shaft. The second end of the wear-resistant mandrel is statically sealed to the mud input connector via a packing assembly. The flange assembly includes a first flange, a flange connection part, and a second flange connected in sequence. The first flange is fixedly connected to the limiting housing, and the second flange is fixedly connected to the mud input joint. The wear-resistant mandrel is axially adjustable to the flange connection part through a connector.

2. The rotary joint according to claim 1, characterized in that, The packing seal box assembly includes a packing box, a packing seal component, a seal box spacer, and a sand-blocking device. The packing seal component is installed on the inner ring of the packing box. The packing seal component includes multiple sets of first packing seals, and adjacent first packing seals are separated by spacer rings. The seal box spacer is installed at the first end of the packing box. The end of the seal box spacer near the packing seal component presses against the packing seal component, and the axial position of the packing box relative to the seal box spacer is adjustable. A sand-blocking device is installed inside the seal box spacer to filter coarse sand particles during construction.

3. The rotary joint according to claim 2, characterized in that, The rotating shaft is equipped with a rotating shaft oil cup, and a lubricating oil channel connected to the rotating shaft oil cup is arranged in the spacer ring of the rotating shaft and the packing seal box assembly. The oil entering through the rotating shaft oil cup can cool and lubricate the first packing seal in the packing box according to the direction of the lubricating oil channel, and at the same time, it can dislodge mud and sand particles from the lip of the first packing seal and the outer ring of the wear-resistant mandrel, thereby extending the service life of the first packing seal.

4. The rotary joint according to claim 2, characterized in that, It also includes a limiting block for axial and circumferentially limiting the second end of the packing seal box assembly. The inner ring of the second end of the rotating shaft is provided with an anti-rotation groove for circumferentially limiting the installation of the limiting block. The first end of the packing seal box assembly is axially limited and installed in the rotating shaft through the first limiting slot. Under the axial and circumferential limiting action of the rotating shaft and the limiting block, the packing seal box assembly does not have axial or circumferential movement.

5. The rotary joint according to claim 2, characterized in that, The second end of the packing seal box assembly is provided with a bushing, the outer ring of the second end of the rotating shaft is provided with a trapezoidal thread, the inner ring of the packing box cover and the round nut is provided with matching trapezoidal threads, the packing box cover and the round nut are threadedly connected to the rotating shaft, and the inner side of the packing box cover is in contact with the bushing, so that the sealing compression and pre-tightening of the packing seal in the packing seal box assembly can be adjusted by rotating the packing box cover and the round nut to press the bushing.

6. The rotary joint according to claim 2, characterized in that, The flange connection is provided with multiple sets of limiting holes with different axial positions for connecting with the wear-resistant mandrel. The wear-resistant mandrel is connected to the limiting holes of the flange connection through the connector, which can adjust the axial position of the wear-resistant mandrel, thereby changing the contact position between the wear-resistant mandrel and the first packing seal lip in the packing seal box assembly.

7. The rotary joint according to claim 1, characterized in that, The packing assembly includes a second packing seal and a packing pressure plate. The connection part of the mud input joint is provided with an installation groove for installing the second packing seal. The second packing seal is installed in the installation groove and is axially limited and pressed by the packing pressure plate.

8. The rotary joint according to claim 1, characterized in that, The limiting housing is provided with a limiting housing oil cup that communicates with the bearing located inside the limiting housing, and is used to enter the oil through the limiting housing oil cup to cool and lubricate the bearing.

9. The rotary joint according to claim 1, characterized in that, The first end of the bearing is axially limited by the flange cover, and the second end of the bearing is axially limited by the first flange of the flange assembly.

10. The rotary joint according to claim 9, characterized in that, A first groove is formed on the flange cover facing the bearing, and a dustproof ring 1 is installed in the first groove; a second groove is formed on the first flange facing the bearing, and a dustproof ring 2 is installed in the second groove. The inner rings of the dustproof ring 1 and the dustproof ring 2 are tightly attached to the outer surface of the rotating shaft to prevent dust and mud from entering the bearing and avoid causing the bearing to seize.

11. A drilling rig, characterized in that, Includes the rotary joint as described in any one of claims 1 to 10.

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