A constant torsion damper

Abstract

This invention provides a constant torsion damper, belonging to the field of drilling technology. It includes an outer cylinder with an inner cavity, comprising an upper connector, an upper sleeve, a splined sleeve, an intermediate cylinder, a connecting body, a lower sleeve, a lower connecting body, and a lower connector connected in sequence; an inner mandrel with a central flow channel, installed within the outer cylinder, comprising an upper mandrel, an intermediate mandrel, a mandrel connecting body, a lower mandrel, and an extension mandrel connected in sequence; and a damping assembly, including a line contact rolling assembly mounted on the upper mandrel, a small disc spring mounted on the intermediate mandrel, and a large disc spring mounted on the lower mandrel. This invention can suppress harmful torsional vibrations during drilling operations, thereby protecting the drill string, increasing drilling speed, and reducing costs.

Description

Technical Field

[0001] This invention relates to the field of drilling technology, and more specifically, to a constant torsion damper. Background Technology

[0002] During drilling, the drill bit is affected by complex geological conditions, generating significant and irregular resistance that causes drill string vibration. Vibration dampers can absorb and convert harmful downhole vibration energy, thereby reducing the impact of vibration on the drill string. Drill string vibration includes axial vibration, lateral vibration, torsional vibration, and the coupling of these three types. Existing vibration dampers have limited overall effectiveness in reducing vibration under complex downhole conditions. Their constant torque function is not significant, making it difficult to stably maintain the preset torque value during drilling. Due to limitations in their structural principles and performance, they cannot effectively suppress severe torsional vibrations generated in the downhole drill string system. Especially when facing strong stick-slip effects, their buffering and energy dissipation capabilities are significantly insufficient, causing the drill string to continuously bear alternating torque and increasing the risk of tool string breakage, thus affecting drilling efficiency and downhole safety. Summary of the Invention

[0003] In order to solve the technical problems existing in the background art, the present invention provides a constant torsion damper that can suppress harmful torsional vibrations in drilling operations, so as to achieve the purpose of protecting the drill string, increasing drilling speed and reducing costs.

[0004] This invention provides a constant torsion damper, comprising:

[0005] The outer cylinder with an inner cavity includes an upper connector, an upper sleeve, a splined sleeve, an intermediate cylinder, a connecting body, a lower sleeve, a lower connecting body, and a lower connector connected in sequence.

[0006] An inner mandrel with a central flow channel is installed inside the outer cylinder and includes an upper mandrel, an intermediate mandrel, a mandrel connector, a lower mandrel, and an extension mandrel connected in sequence.

[0007] The damping assembly includes a line contact rolling assembly mounted on the upper spindle, a small disc spring mounted on the middle spindle, and a large disc spring mounted on the lower spindle.

[0008] The outer periphery of the upper mandrel has a discrete internal spiral structure.

[0009] Furthermore, the upper end of the upper mandrel mates with the inner end of the upper connector, and the inner cavity of the lower connector is provided with a limiting structure adapted to the extension mandrel.

[0010] Furthermore, the line contact rolling assembly includes a rolling nut, a rolling sleeve, and a rolling screw.

[0011] Furthermore, the upper mandrel is installed in the inner cavity of the upper sleeve, spline sleeve, and intermediate cylinder; the intermediate mandrel is installed in the inner cavity of the intermediate cylinder, connecting body, and lower sleeve; the mandrel connecting body is installed in the inner cavity of the lower sleeve; the lower mandrel is installed in the inner cavity of the lower sleeve, lower connecting body, and lower connector; and the extension mandrel is installed in the inner cavity of the lower connector.

[0012] Furthermore, the line contact rolling assembly is disposed in the inner cavity of the upper sleeve, the small disc spring is disposed in the inner cavity of the middle sleeve, and the large disc spring is disposed in the inner cavity of the lower sleeve.

[0013] Furthermore, an adjusting ring is provided between the mandrel connector and the lower sleeve.

[0014] Furthermore, the lower mandrel is provided with a balance piston, an anti-drop ring, a first sealing assembly, and a second sealing assembly from top to bottom on its outer periphery. The balance piston, the anti-drop ring, and the first sealing assembly are disposed in the inner cavity of the lower connector, and the second sealing assembly is disposed in the inner cavity of the lower connector.

[0015] Furthermore, a third sealing assembly is provided at both the upper and lower ends of the outer periphery of the extended mandrel, and the third sealing assembly is located in the inner cavity of the lower connector.

[0016] The beneficial effects of this invention are as follows:

[0017] This invention provides a constant torque damper with innovative structure, wide application, good performance, and suitability for complex downhole conditions. It employs a disc spring zoning structure, where low-amplitude high-frequency vibrations act on the smaller disc springs, while high-amplitude low-frequency vibrations act on the larger disc springs. This efficiently absorbs vibration energy, ensuring effective damping. Using silicone oil as a medium, the compressed silicone oil absorbs energy, further enhancing the damping effect. This gives the constant torque damper a multi-stiffness gradient damping effect, enabling it to cope with complex well conditions and further ensuring the stability of the constant torque damping function. The discrete internal spiral structure with 16 contact points ensures smoother and more stable vibration transmission, improving the tool's durability and impact resistance under harsh well conditions, thus contributing to the constant torque function. The rolling friction coefficient is lower, and the line contact bearing capacity is stronger, further ensuring smoother and more constant torque transmission. Furthermore, the uniform wear of the line contact structure avoids stress concentration at certain points during torque transmission, preventing a reduction in damping effect. The inertial effect of the pump start-up pressure on the constant torque damper is eliminated, preventing the damper from stretching and affecting its damping effect. Furthermore, the disc spring can store the energy of the pump start-up force, which can assist in subsequent damping. When the end face of the constant torque damper spindle is in contact with the shaft, a structure on the spindle allows hydraulic oil to flow, forming a stable lubricating oil film, further assisting in damping and buffering. This achieves a coordinated function of damping protection and shock release during tool string operation. Protected by the limiting structure, the disc spring is not affected by the shock absorber, preventing damage to the disc spring. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the present invention;

[0019] Figure 2 This is a schematic diagram of the compression stroke of the constant torsion damper of the present invention;

[0020] Figure 3 This is a schematic diagram of the torque values ​​of the constant torsion damper of the present invention;

[0021] Figure 4 This is a schematic diagram of the torque fluctuation and torsional structure of the constant torsion damper of the present invention;

[0022] Figure 5 This is a schematic diagram of the line contact rolling assembly of the present invention;

[0023] Figure 6 This is a schematic diagram of the lower connector and extension mandrel structure and an oil circuit diagram of the present invention;

[0024] Figure 7 This is a schematic diagram of the intermediate spindle and small disc spring structure and a schematic diagram of the oil circuit of the present invention;

[0025] Figure 8 This is a schematic diagram of the downward pressing structure of the constant torsion damper of the present invention and an enlarged view of the position of the spline sleeve;

[0026] Figure 9 This is a schematic diagram of the lifting structure of the constant torsion damper of the present invention and an enlarged view of the position of the spline sleeve;

[0027] In the diagram: 1-Upper connector, 2-Upper sleeve, 3-Upper mandrel, 4-Line contact rolling assembly, 5-Spline sleeve, 6-Intermediate cylinder, 7-Intermediate mandrel, 8-Small disc spring, 9-Connector, 10-Mandrel connector, 11-Adjusting ring, 12-Lower sleeve, 13-Lower mandrel, 14-Large disc spring, 15-Lower connector, 16-Balance piston, 17-Anti-drop ring, 18-First sealing assembly, 19-Second sealing assembly, 20-Lower connector, 21-Extension mandrel, 22-Third sealing assembly, 401-Rolling nut, 402-Rolling sleeve, 403-Rolling screw. Detailed Implementation

[0028] The exemplary embodiments of this disclosure are described below with reference to the accompanying drawings, including various details of the embodiments to aid understanding, and should be considered merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this disclosure. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

[0029] Please see Figure 1This invention discloses a constant torsion damper, comprising: an outer cylinder, an inner core shaft, and a damping assembly.

[0030] Specifically, the outer cylinder includes an upper connector 1, an upper sleeve 2, a spline sleeve 5, an intermediate cylinder 6, a connecting body 9, a lower sleeve 12, a lower connecting body 15, and a lower connector 20 connected in sequence; the inner mandrel is installed inside the outer cylinder and includes an upper mandrel 3, an intermediate mandrel 7, a mandrel connecting body 10, a lower mandrel 13, and an extension mandrel 21 connected in sequence; the shock absorption assembly includes a line contact rolling assembly 4 installed on the upper mandrel 3, a small disc spring 8 installed on the intermediate mandrel 7, and a large disc spring 14 installed on the lower mandrel 13;

[0031] Among them, the outer periphery of the upper mandrel 3 has a discrete inner spiral structure.

[0032] In this embodiment, the upper end of the upper mandrel 3 mates with the inner end of the upper connector 1, and the inner cavity of the lower connector 20 is provided with a limiting structure adapted to the extension mandrel 21. The line contact rolling assembly 4 includes a rolling nut, a rolling sleeve, and a rolling screw. The upper mandrel 3 is installed in the inner cavities of the upper sleeve 2, the spline sleeve 5, and the intermediate cylinder 6; the intermediate mandrel 7 is installed in the inner cavities of the intermediate cylinder 6, the connecting body 9, and the lower sleeve 12; the mandrel connecting body 10 is installed in the inner cavity of the lower sleeve 12; the lower mandrel 13 is installed in the inner cavities of the lower sleeve 12, the lower connecting body 15, and the lower connector 20; and the extension mandrel 21 is installed in the inner cavity of the lower connector 20. The line contact rolling assembly 4 is disposed in the inner cavity of the upper sleeve 2; the small disc spring 8 is disposed in the inner cavity of the intermediate cylinder 6; and the large disc spring 14 is disposed in the inner cavity of the lower sleeve 12. An adjusting ring 11 is provided between the mandrel connecting body 10 and the lower sleeve 12.

[0033] The lower spindle 13 has a balance piston 16, an anti-drop ring 17, a first sealing assembly 18, and a second sealing assembly 19 arranged from top to bottom on its outer periphery. The balance piston 16, the anti-drop ring 17, and the first sealing assembly 18 are located in the inner cavity of the lower connector 15, and the second sealing assembly 19 is located in the inner cavity of the lower connector 20. The extension spindle 21 has a third sealing assembly 22 arranged at both the upper and lower ends on its outer periphery. The third sealing assembly 22 is located in the inner cavity of the lower connector 20.

[0034] When the tool string is working, the lower connector 20 of the constant torsion damper connected to the drill bit will drive the lower connector 15, lower sleeve 12, connector 9, intermediate cylinder 6 and spline sleeve 5 to move. A large disc spring 14 is installed between the lower sleeve 12 and the lower mandrel 13, and a small disc spring 8 is installed between the intermediate cylinder 6 and the intermediate mandrel 7. The two disc spring areas are isolated by the mandrel connector 10, and they do not affect each other when they are in operation.

[0035] As the outer cylinder moves, the lower connector 20 and the lower connecting body 15 transmit low-frequency, high-amplitude vibrations to the large disc spring 14, which absorbs energy and dampens vibrations. The lower connector 20, the lower connecting body 15, the lower sleeve 12, and the connecting body 9 transmit high-frequency, low-amplitude vibrations to the small disc spring 8, which absorbs energy and dampens vibrations. At the same time, the radial vibrations on the outer cylinder can also drive the line contact rolling assembly 4 to make it helical displacement through the spline sleeve 5. Since the upper connector 1 and the upper spindle 3 are connected, the force converted by the helical displacement of the line contact rolling assembly 4 on the upper spindle 3 finally acts on the small disc spring 8, which then absorbs energy and dampens vibrations.

[0036] Constant torsion dampers use silicone oil as a medium. When silicone oil is compressed, it absorbs energy and dampens vibrations.

[0037] like Figure 2 As shown, when the constant torque damper is not affected by torque, the upper sleeve 2 and the spline sleeve 5 have an initial stroke L; when the constant torque damper is compressed, and the stroke of the upper sleeve 2 and the spline sleeve 5 reaches 1 / 2L, the balance piston 16 will reach the limit with the anti-drop ring 17, at which point the adjustment function of the balance piston 16 will fail.

[0038] like Figure 3 As shown, the silicone oil begins to be compressed. At this time, the silicone oil and the disc spring work together to form a new damping stiffness, which can play a damping protection role when the torque of the constant torsion damper stops or when the torque of the drill impactor is above 30,000 N.m.

[0039] like Figure 1 , Figure 4 and Figure 5 As shown, when the tool string is subjected to vibration and torque fluctuations, the lower connector 20 connecting the drill bit will cause the lower connector 15, lower sleeve 12, connector 9, intermediate cylinder 6, and spline sleeve 5 to shift or twist together. The discrete internal helical structure of the upper mandrel 3 can absorb and buffer a portion of the radial vibration energy, converting it into the elastic potential energy of the helical structure, thereby reducing the impact of vibration. Figure 4 As shown in the structure, it can also transmit torque, adapting to torque fluctuations through the adjustment of the helical structure itself, allowing the drill bit to maintain relatively stable torque under different drilling conditions. Torque fluctuations are as follows: Figure 4 The torque fluctuation is shown. Simultaneously, a line contact rolling assembly 4 is added to the upper mandrel 3, spline sleeve 5, and upper sleeve 2 to assist in vibration damping and torque transmission. The line contact rolling assembly 4 consists of a rolling nut 401, a rolling sleeve 402, and a rolling screw 403. When the line contact rolling assembly 4 is displaced, relative rolling also occurs inside it. Its lower coefficient of friction allows for smoother tool movement and reduces energy loss. The smooth rolling line contact between the line contact rolling assembly 4 and the raceway also makes torque transmission more stable.

[0040] like Figure 6As shown, when the pump-starting force is transmitted to the inside of the constant torsion damper, it can be transmitted to the chamber formed by the lower spindle 13, the anti-drop ring 17, and the lower connector 20. The chamber formed by the lower connector 20 and the extended spindle 21 is connected to the downhole annulus. Since the annulus pressure is lower than the pump-starting pressure, the pump-starting pressure acts on the extended spindle 21, causing the extended spindle 21 to move downwards. The pressure difference is converted into potential energy, causing the constant torsion damper to compress as a whole. The disc spring can absorb the pump-starting force. This avoids the constant torsion damper from stretching under inertia due to the pump-starting pressure, which would affect the damping effect.

[0041] like Figure 7 As shown in the figure, the enlarged part is the oil passage hole at the location of the small disc spring. The entire constant torsion damper has a circulating oil passage structure inside. When the constant torsion damper is lifted or pressed down, the end face of the internal spindle is in contact, and the hydraulic oil can flow with low resistance and without obstruction from the flow channel designed for the spindle, ensuring that the entire constant torsion damper can obtain sufficient oil film protection during the working stroke; and the damping effect generated when the hydraulic oil flows under pressure can also convert some of the impact energy into the heat energy of the hydraulic oil and dissipate it.

[0042] like Figure 8 , Figure 9 As shown in the diagram, the enlarged portions are schematic diagrams of the spline sleeve positions. A limiting structure allows the constant torque damper to be connected to the shock absorber. During the initial downward and upward movements of the constant torque damper, the relative movement between the outer cylinder and the spindle compresses the disc spring. This compression stops when the limiting end faces engage, reaching the limit position. At this point, activating the shock absorber prevents the constant torque damper from operating due to its vibration. For tool strings, this provides both prevention and unblocking protection. Early damping creates favorable working conditions for the shock absorber, optimizing the shock effect and improving drilling efficiency and safety.

[0043] The specific embodiments described above do not constitute a limitation on the scope of protection of this disclosure. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A constant-torque shock absorber characterized by, include: The outer cylinder with an inner cavity includes an upper connector, an upper sleeve, a splined sleeve, an intermediate cylinder, a connecting body, a lower sleeve, a lower connecting body, and a lower connector connected in sequence. An inner mandrel with a central flow channel is installed inside the outer cylinder and includes an upper mandrel, an intermediate mandrel, a mandrel connector, a lower mandrel, and an extension mandrel connected in sequence. The damping assembly includes a line contact rolling assembly mounted on the upper spindle, a small disc spring mounted on the middle spindle, and a large disc spring mounted on the lower spindle. The outer periphery of the upper mandrel has a discrete internal spiral structure, and the line contact rolling assembly is set in the inner cavity of the upper sleeve. The line contact rolling assembly includes a rolling nut, a rolling sleeve, and a rolling screw; As the outer cylinder moves, the lower joint and lower connecting body transmit low-frequency, high-amplitude vibrations to the large disc spring, which absorbs energy and dampens the vibrations. The lower joint, lower connecting body, lower sleeve, and connecting body transmit high-frequency, low-amplitude vibrations to the small disc spring, which absorbs energy and dampens the vibrations. At the same time, the radial vibrations on the outer cylinder drive the line contact rolling assembly to make it helical displacement through the spline sleeve. The force converted by the helical displacement of the line contact rolling assembly on the upper spindle finally acts on the small disc spring, which then performs the final energy absorption and damping. When the tool string is subjected to vibration and torque fluctuations, the lower connector of the drill bit causes the lower connector, lower sleeve, connector, intermediate cylinder and spline sleeve to move or twist together. The discrete inner helical structure of the upper mandrel absorbs and buffers part of the radial vibration energy and converts it into the elastic potential energy of the helical structure, thereby reducing the impact of vibration. It transmits torque by adjusting the spiral structure itself to adapt to torque fluctuations. An adjusting ring is provided between the mandrel connector and the lower sleeve. A balance piston, an anti-drop ring, a first sealing assembly, and a second sealing assembly are provided from top to bottom on the outer circumference of the lower mandrel. The balance piston, the anti-drop ring, and the first sealing assembly are located in the inner cavity of the lower connector, and the second sealing assembly is located in the inner cavity of the lower connector.

2. A constant-torque shock absorber according to claim 1, characterized in that: The upper end of the upper mandrel mates with the inner end of the upper connector, and the inner cavity of the lower connector is provided with a limiting structure adapted to the extension mandrel.

3. A constant-torque shock absorber according to claim 1, wherein: The upper mandrel is installed in the inner cavity of the upper sleeve, spline sleeve and intermediate cylinder; the intermediate mandrel is installed in the inner cavity of the intermediate cylinder, connecting body and lower sleeve; the mandrel connecting body is installed in the inner cavity of the lower sleeve; the lower mandrel is installed in the inner cavity of the lower sleeve, lower connecting body and lower connector; and the extension mandrel is installed in the inner cavity of the lower connector.

4. A constant-torque shock absorber according to claim 1, wherein: The small disc spring is located in the inner cavity of the middle cylinder, and the large disc spring is located in the inner cavity of the lower sleeve.

5. A constant-torque shock absorber according to claim 1, wherein: The upper and lower ends of the outer periphery of the extension mandrel are respectively provided with a third sealing component, which is located in the inner cavity of the lower connector.

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