Reamer

Abstract

The reamer comprises a reamer body, and the reamer body is provided with a movable cavity, a reaming opening, an inlet end and an outlet end. A blade; a piston; the piston is provided with a first end, a second end, a first runner and a first through hole; the first end is connected with the blade, the outer wall of the second end and the inner wall of the movable cavity are spaced and form a first guide runner, and a pushing part is arranged at the end part of the second end; the guide assembly comprises a guide sleeve, a movable rod and an actuator, the guide sleeve is provided with a first section and a second section, the first section and the inner wall of the movable cavity are arranged in a spaced mode, and a second guide flow channel is formed; the first section is provided with a first guide hole, and the outer wall of the second section is in sealing fit with the inner wall of the movable cavity; the movable rod is provided with a second flow channel and a second through hole, and the second flow channel is communicated with the first flow channel; the first guide hole corresponds to the second through hole. The actuator can guide the piston connected with the blade to move according to the flow change, so that the blade is in different use states.

Description

Technical Field

[0001] This invention relates to the field of drilling equipment technology, and more particularly to a borehole reamer. Background Technology

[0002] Currently, the reamer, also known as an enlarging reaming bit, is a tool used to enlarge the wellbore during drilling in oil wells. Unlike reaming bits, which are mounted at the bottom of the drill string, the reamer is mounted in the middle of the drill string and has a diameter slightly smaller than that of the drill bit. As the drill bit below drills, the reamer simultaneously enlarges the wellbore and trims the borehole wall.

[0003] Since the reamer is usually located inside the formation after the drill bit enters, when the drilling depth is relatively deep, it is not necessary to observe the operating status of the reamer. However, when the flow rate and pressure inside the reamer change, the operating status of the reamer cannot be switched in time according to the flow rate and pressure. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the present invention aims to provide an eye expander, wherein the actuator is provided to guide the movement of the piston connected to the blade according to the flow rate change, so that the blade can be in different usage states.

[0005] The objective of this invention is achieved through the following technical solution: An eye expander, comprising, The eye expander body has a movable cavity, an eye expander opening, an inlet end, and an outlet end. The eye expander opening is located on the outer surface of the eye expander body and communicates with the movable cavity along the radial direction of the eye expander body. The inlet end and the outlet end are respectively located at the two ends of the axial direction of the movable cavity. Blade wing, which is movably mounted on the eyelet opening and can move closer to or further away from the eyelet opening; A piston is installed within the movable cavity and moves axially towards or away from the outlet end. The piston has a first end, a second end, a first flow channel, and a first through hole. The first end is connected to the blade and guides the blade's movement when moving axially within the movable cavity. The outer wall of the second end is spaced from the inner wall of the movable cavity to form a first guide flow channel. A pushing portion is provided at the end of the second end, and this pushing portion is in a sealing sliding fit with the inner wall of the movable cavity. The first through hole and the pushing portion are axially spaced within the movable cavity and guide fluid into the first guide flow channel. A guiding assembly includes a guide sleeve, a movable rod, and an actuator. The guide sleeve has a first through-section, a first section, a second section, and a second through-section. The outer wall of the first through-section is sealed to the inner wall of the movable cavity. The first section and the second section are spaced apart from the inner wall of the movable cavity to form a second guiding flow channel. The first section has a first guiding hole, and the second section has a second guiding hole. The second through-section passes through the piston and slides with the piston. The movable rod has a second flow channel and a second through hole. The second flow channel communicates with the first flow channel. The first guiding hole communicates with the second through hole to guide fluid into the second guiding channel. The second guiding hole corresponds to the first through hole and guides fluid into the first guiding flow channel. The actuator guides the movable rod to move according to the flow rate change of the second flow channel. Further, the actuator includes... The housing includes an inlet channel, an outlet channel, and a cavity. The inlet channel is connected to one end of the cavity, and the outlet channel is connected to the other end of the cavity. The inner peripheral wall of the cavity has a sealing portion. The housing is movably connected to the movable cavity and to the movable rod. The inlet channel is connected to the second flow channel. A second elastic member is clamped between the housing and the end wall of the outlet end. A valve body assembly, installed in the cavity, includes a spindle, a start valve, and a first elastic component. The spindle has a third end and a fourth end, the third end abutting against the end wall of the cavity. The outer peripheral wall of the third end is spaced from the inner peripheral wall of the cavity to form a first flow-guiding interval. The outer peripheral wall of the third end has a first through hole, and the third end has a through cavity, the first through hole communicating with the through cavity. The through cavity communicating with the outlet channel. The start valve is slidably installed on the fourth end and spaced from the inner peripheral wall of the cavity to form a second flow-guiding interval. The start valve is used to move closer to the closure under external force to block the second flow-guiding interval. The first elastic component provides an elastic stress that drives the start valve away from the closure. The start valve has a second through hole for connecting the inlet channel and the first flow-guiding interval.

[0006] Furthermore, the outer peripheral wall of the housing is provided with a first guide groove, a second guide groove, and a third guide groove. The first guide groove, the second guide groove, and the third guide groove all extend along the axial direction of the housing and are spaced apart in the circumferential direction of the housing. The first guide groove and the second guide groove are connected and communicate with each other through an inclined guide groove section, and the second guide groove and the third guide groove are connected and communicate with each other through an inclined guide groove section. The first guide groove and the third guide groove are spaced apart from the second guide groove in the axial direction. The outer casing is rotatably fitted with a limiting sleeve, which is provided with a limiting post. The limiting post slides in conjunction with the first guide groove, the second guide groove, the third guide groove, and the inclined guide groove.

[0007] Furthermore, the starting valve has an installation cavity, the fourth end passes through the installation cavity and is slidably engaged; the first elastic member is disposed in the installation cavity and abuts against the end wall of the installation cavity; the fourth end has an abutment step, and the first elastic member is clamped between the abutment step and the end wall of the installation cavity.

[0008] Furthermore, the first end is provided with a third through hole; the eye expander body is provided with a spray channel; a nozzle is provided in the spray channel, and the third through hole is used to communicate with the spray channel; the end of the movable rod away from the actuator is movably connected to the first flow channel and is used to close or open the third through hole.

[0009] Furthermore, the outer wall of the first end is provided with a plurality of first limiting tooth grooves; the blade is provided with a connecting block, the inner wall of the connecting block is provided with a plurality of second limiting tooth grooves, and the connecting block is connected to the first end so that the second limiting tooth grooves mesh with the first limiting tooth grooves.

[0010] Furthermore, the second through hole is provided in three rows, and the three rows of the second through hole are distributed at intervals along the axial direction of the movable rod.

[0011] Furthermore, the inner wall of the movable cavity is provided with a first protruding step, which is located on the inner wall of the movable cavity near the inlet end. The first protruding step is sealed to the end face of the first through section of the guide sleeve facing the outlet end. The end face of the first through section facing the inlet end is provided with a second protruding step, which forms the second guide flow channel between the push-up portion and the first protruding step.

[0012] Furthermore, the pushing portion includes a pushing inclined surface circumferentially disposed around the outer periphery of the second end of the piston.

[0013] Furthermore, a limiting shaft passes through the movable cavity, and the limiting shaft is used to abut against the blade after the blade moves close to the inner side of the reamer; the piston rod is mounted on the end of the limiting shaft; the limiting shaft is provided with a guiding channel, and the guiding channel is connected to the first channel.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: The operating state of the expander can be switched according to the fluid pressure inside the expander in conjunction with the actuator. The actuator only needs to adjust the flow rate and pressure of the first and second flow channels to make the piston connected to the blade move in different directions axially, thereby switching the operating state and making it easy to use. Attached Figure Description

[0015] Figure 1 This is a cross-sectional view of the present invention; Figure 2 This is a cross-sectional view of the actuator of the present invention; Figure 3 This is a schematic diagram of the structure of the housing of the present invention; Figure 4 This is a schematic diagram of the assembly structure of the starting valve and the spindle of the present invention; Figure 5 This is a schematic diagram of the structure of the starting valve of the present invention; Figure 6 This is a schematic diagram of the mandrel structure of the present invention; Figure 7 This is a schematic diagram of the piston structure of the present invention; Figure 8 This is a schematic diagram of the guide sleeve of the present invention; Figure 9 This is a schematic diagram of the structure of the movable rod of the present invention.

[0016] In the diagram: 1. Eye expander body; 101. Inlet end; 102. Outlet end; 103. Movable cavity; 104. First guide channel; 105. First protruding step; 106. Limiting shaft; 107. Spray channel; 108. Nozzle; 109. Second guide channel; 10. Housing; 11. Cavity; 111. Sealing part; 12. Outlet channel; 13. Inlet channel; 14. First guide interval; 15. Second guide interval; 20. Mandrel; 21. Third end; 211. Guide cavity; 212. First through hole; 22. Fourth end; 30. Start valve; 31. Second through hole; 32. Mounting cavity; 40. First elastic component; 50. Second elastic component; 60. Blade; 61. Connecting block; 70. Piston; 71. First flow channel; 711. Pushing part; 72. First through hole; 73. Third through hole; 74. First limiting tooth groove; 80. Guide sleeve; 81. First section; 82. Second section; 83. First guide hole; 84. Second guide hole; 85. First through section; 86. Second through section; 90. Movable rod; 91. Second flow channel; 92. Second through hole. Detailed Implementation

[0017] The present invention will now be further described with reference to the accompanying drawings and specific embodiments: In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not 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 invention.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0019] like Figure 1-9 The illustrated expander includes an expander body 1, blades 60, a piston 70, and a guide assembly. The expander body 1 has a movable cavity 103, an expanding opening, an inlet end, and an outlet end 102. The expanding opening is located on the outer surface of the expander body 1 and extends radially into the movable cavity 103. The inlet end and outlet end 102 are located at opposite ends of the movable cavity 103 along its axial direction. The inlet end guides fluid into the movable cavity 103, while the outlet end 102 guides fluid out of the movable cavity 103. The blades 60 are movably mounted to the expanding opening and can move closer to or further away from the opening, allowing them to be retracted into or extended from the opening.

[0020] Specifically, the piston 70 is installed in the movable cavity 103, and the piston 70 can move closer to or away from the outlet end 102 along the axial direction of the movable cavity 103. The piston 70 is provided with a first end, a second end, a first flow channel 71, and a first through hole 72. The first end is connected to the blade 60 and guides the blade 60 to move when it moves along the axial direction of the movable cavity 103. The outer wall of the second end is spaced apart from the inner wall of the movable cavity 103 and forms a first guide flow channel 104. The end of the second end is provided with a push part 711, which is in a sealing sliding fit with the inner wall of the movable cavity 103. The first through hole 72 and the push part 711 are distributed axially in the movable cavity 103 and guide the fluid into the first guide flow channel 104.

[0021] It should be noted that the aforementioned pusher 711 can be formed by a stepped structure surrounding the second end of the piston 70, or an annular rib structure, or an inclined structure surrounding the second end of the piston 70. In short, any structure that can provide pressure to push the fluid is acceptable. When the pusher 711 is subjected to fluid pressure, it can drive the piston 70 to move toward the inlet end 101 or outlet end 102 of the movable cavity 103, thereby guiding the blade 60 connected to the first end of the piston 70 to move.

[0022] In addition, the guiding assembly includes a guide sleeve 80, a movable rod 90, and an actuator. The guide sleeve 80 is fitted onto the outside of the movable rod 90. The guide sleeve 80 is provided with a first through section 85, a second through section 86, a first section 81, and a second section 82. Specifically, the first through section 85 is sealed to the inner wall of the movable cavity 103. The second through section 86 passes through the piston 70 and slides with the piston. The first section 81 and the second section 82 are connected and spaced apart from the inner wall of the movable cavity 103, forming a second guiding channel 109. The first section 81 is provided with a first guiding hole 83, and the second section 82 is provided with a second guiding hole 84. The outer diameter of the second section can be smaller than the outer diameter of the first section. When the piston 70 moves, the second through section 86 moves relative to the piston 70.

[0023] The movable rod 90 is provided with a second flow channel 91 and a second through hole 92. The second flow channel 91 is connected to the first flow channel 71. When the guide sleeve 80 moves, the first guide hole 83 or the second guide hole 84 corresponds to the second through hole 92 and guides fluid into the second guide flow channel 109 or the first guide flow channel 104 to drive the movable rod 90 and the piston 70 to move. The actuator can guide the movable rod 90 to move according to the flow rate change of the second flow channel 91. The piston 70 slides relative to the second section 82 of the guide sleeve, so that at this time, the second through hole 92 of the movable rod 90 corresponds to the second guide hole 84 of the second section 82 and the first through hole 72 of the movable piston, guiding the fluid into the first guide channel 104.

[0024] When the movable rod moves relative to the guide sleeve until the first through hole 72 of the piston corresponds to the first guide hole 83 of the first section 81 of the guide sleeve 80, the second guide hole 84 of the second section 82 of the guide sleeve is misaligned with the first through hole 72, and the first guide hole 83 of the first section 81 is connected to the second through hole 92. After the guide fluid enters the second guide channel 109, the fluid pressure pushes the piston 70 and the blade to move closer to the inlet end 101.

[0025] Based on this structure, when using the eye expander of the present invention, When the blade 60 is not extended, the second end of the piston 70 corresponds to the second section of the guide sleeve, and the first through hole 72 of the piston is misaligned with the second guide hole 84 of the second section 82 of the guide sleeve 80. At this time, fluid can be guided into the active chamber 103 through the inlet end of the active chamber 103, and guided to the second flow channel 91 of the guide rod 90 through the first flow channel 71. At this time, the water flow in the second flow channel 91 flows to the actuator, applying fluid pressure to the actuator. The actuator is in a non-starting state under the action of the fluid pressure.

[0026] After the fluid pump is turned on, the fluid pressure entering the second flow channel 91 through the first flow channel 71 increases. The fluid in the second flow channel 91 passes through the actuator and pushes the actuator to move towards the outlet end 102. At this time, the movable rod 90 connected to the actuator can move towards the outlet end 102. When the second through hole 92 on the movable rod 90 corresponds to the first guide hole 83 of the first section 81 of the guide sleeve 80, part of the fluid in the second flow channel 91 can pass through the second through hole 92 on the movable rod 90 and the first guide hole 83. 83 is guided to the second guide channel 109. The fluid pressure in the second guide channel 109 can be applied to the end face of the piston 70's push part 711 facing the outlet end. At this time, the end face of the push part 711 facing the outlet end is pressurized. The fluid pressure comes from the second guide channel 109, which can push the piston 70 to move towards the inlet end 101. In this way, the first end of the piston 70 can drive the cutter 60 to move towards the inlet end 101, pushing the cutter 60 to extend through the reaming orifice. At this time, the drill bit performs the reaming action.

[0027] After the blade is enlarged, the piston 70 moves toward the inlet end 101, allowing it to slide relative to the second through section 86 of the guide sleeve 80. During this sliding process, the piston 70 slides relative to the guide sleeve 80 until it corresponds to the second section 82 of the guide sleeve, and the first through hole 72 of the piston slides until it corresponds to and connects with the second guide hole 84 of the second section 82. In this state, water flows in along the center of the inlet end of the movable cavity 103, through the first flow channel 71 and the second flow channel 91. The fluid in the second flow channel 91 can enter the first guide flow channel 104 through the second through hole 92, the second guide hole 84, and the first through hole 72. The fluid pressure in the first guide flow channel 104 can then act on the piston's pusher 711 facing the inlet end, pushing the piston away from the inlet end and causing the blade to retract.

[0028] After the blade 60 extends, in order to ensure that the blade 60 operates safely in the expanded eye state, the inlet flow rate of the fluid pump can be reduced, or the pump can be turned off and restarted to a low discharge rate. The flow channel remains unchanged, the pressure decreases, and the actuator does not start.

[0029] Of course, after restarting the pump, once the cutter wing 60 extends and operates in the expanded-eye state for a period of time, if it is necessary to retract the cutter wing, the fluid pump can be stopped. At this time, the fluid pressure in the first flow channel 71 entering the second flow channel 91 decreases. After receiving the fluid change, the actuator can begin the reset action, driving the connected movable rod 90 to move away from the outlet end 102. The fluid pressure in the second guide flow channel 109 drives the second end of the piston 70 to move towards the inlet end 101, so that the first through hole 72 on the piston 70 is connected to the second guide hole 84. In this way, the fluid in the first flow channel 71 can partially enter the first guide flow channel 104, pushing the inclined surface of the piston 70 towards the outlet end 102, which can push the piston 70 towards the outlet end 102, starting the cutter wing 60 retraction action. At this time, it can return to the state before drilling.

[0030] Specifically, in this embodiment, the actuator includes a housing 10 and a valve body assembly. The housing 10 is provided with an inlet channel 13, an outlet channel 12, and a cavity 11. The inlet channel 13 is connected to one end of the cavity 11; the outlet channel 12 is connected to the other end of the cavity 11; and the inner peripheral wall of the cavity 11 is provided with a sealing portion 111. The housing 10 of the actuator is movably connected to the movable cavity 103 and connected to the movable rod 90. Based on this structure, the inlet channel 13 of the housing 10 is connected to the second flow channel 91 of the movable rod 90, and a second elastic member 50 is clamped between the housing 10 and the end wall of the outlet end 102. The valve body assembly is installed in the cavity 11. The valve body assembly includes a spindle 20, an actuating valve 30, and a first elastic component 40. The spindle 20 has a third end 21 and a fourth end 22. The third end 21 abuts against the end wall of the cavity 11. The outer peripheral wall of the third end 21 and the inner peripheral wall of the cavity 11 are spaced apart to form a first flow guiding interval 14. The outer peripheral wall of the third end 21 is provided with a first through hole 212, and a through cavity is provided inside the third end 21. The first through hole 212 communicates with the through cavity. The through cavity communicates with... The outlet channel 12 is connected; the start valve 30 is slidably mounted on the fourth end and forms a second flow guide interval 15 with the inner peripheral wall of the cavity 11; the start valve 30 is used to move close to the closure part 111 under the action of external force to block the second flow guide interval 15; the first elastic member 40 is used to provide an elastic stress that drives the start valve 30 away from the closure part 111; the start valve 30 has a second through hole 31, which is used to connect the inlet channel 13 and the first flow guide interval 14.

[0031] Based on this structure, when the eye-expanding action begins, the fluid will enter the inlet channel 13 of the housing 10 through the first flow channel 71 and the second flow channel 91, and then enter the cavity 11. At this time, the second elastic component 50 is in a normal pre-compression state, and the start valve 30 is kept away from the closed part 111 under the action of the first elastic stress, that is, the cavity 11 is in a non-blocking state. At this time, the second conduction interval is connected to the first conduction interval. The fluid introduced by the inlet channel 13 enters the cavity 11 and flows to the first conduction interval through the second conduction interval around the start valve 30. At the same time, the fluid entering the cavity 11 can also flow to the first conduction interval through the second conduction hole 31 on the start valve 30. At this time, the fluid can enter the first conduction interval through two channels at the same time, and then enter the conduction cavity through the first conduction hole 212 to exit through the outlet channel 12. At this time, the interception area is relatively large, and the pressure difference between the pressure at the end of the inlet channel 13 and the pressure at the end of the outlet channel 12 is in a normal pressure difference state. The actuator remains in a non-starting state under this pressure difference.

[0032] When the fluid pump is started, the fluid flow rate in the first flow channel 71 and the second flow channel 91 increases. With the increase in fluid flow rate, the fluid introduced through the inlet channel 13 will pressurize the start valve 30. Under the action of fluid pressure, the start valve 30 moves toward the position close to the closed part 111. The pressure generated breaks through the pre-tightening force applied to the start valve by the second elastic component, pushing the second elastic component to compress again. As the flow rate continues to increase, the start valve 30 will continue to advance toward the closed part 111 until it comes into contact with the closed part 111. The cavity 11 is in a blocked state. At this time, the second conduction interval and the first conduction interval are in a non-conducting state. The fluid entering the cavity 11 through the inlet channel 13 can only enter the first conduction interval through the second conduction hole 31. That is, the pressure of the fluid entering the first conduction interval will change instantaneously when the interception area decreases rapidly. After the instantaneous pressure change, the entire housing 10 moves toward the outlet end 102, which at the same time drives the movable rod 90 to move toward the outlet end 102, starting the eye-opening action.

[0033] After the actuator housing 10 moves toward the outlet end 102, the second elastic component 50 is compressed, facilitating subsequent reset. Using such an actuator, the expansion and retraction states of the blade 60 can be switched directly based on changes in internal fluid flow, making operation convenient.

[0034] It should be noted that the aforementioned enclosed part 111 can be formed by a stepped surface structure set on the inner wall of the wall.

[0035] Furthermore, the outer peripheral wall of the housing 10 is provided with a first guide groove, a second guide groove, and a third guide groove. The first guide groove, the second guide groove, and the third guide groove all extend along the axial direction of the housing 10 and are distributed at intervals in the circumferential direction of the housing 10. The first guide groove and the second guide groove are connected and communicate with each other through an inclined guide groove section. The second guide groove and the third guide groove are connected and communicate with each other through an inclined guide groove section. The first guide groove and the third guide groove are spaced apart from the second guide groove in the axial direction. The housing 10 is rotatably fitted with a limiting sleeve. The limiting sleeve is provided with a limiting post, which slides in conjunction with the first guide groove, the second guide groove, the third guide groove, and the inclined guide groove.

[0036] Thus, as the fluid pressure inside the housing 10 continuously changes, the housing 10 moves axially along the movable cavity 103. Since the limiting sleeve is equipped with a limiting post, and the limiting sleeve rotates relative to the movable cavity 103 while maintaining its axial position, the limiting post can slide within the first, second, and third guide grooves during the axial movement of the housing 10. When the limiting post engages with different guide grooves, the axial position of the actuator's housing 10 can be limited by the limiting post. Furthermore, when the housing 10 moves axially, the limiting post can be guided by the inclined guide groove, allowing it to slide from the first guide groove to the second guide groove, or vice versa.

[0037] The first guide groove, the second guide groove, and the third guide groove extend in the axial direction of the housing 10 and are located at different positions in the axial direction of the housing 10. Therefore, they can cooperate with the limiting post to limit the position of the housing 10 in different states.

[0038] Furthermore, the start valve 30 is provided with an installation cavity 32, and the fourth end 22 passes through the installation cavity 32 and slides into it; the first elastic member 40 is provided in the installation cavity 32 and abuts against the end wall of the installation cavity 32; the fourth end 22 is provided with an abutment step, and the first elastic member 40 is clamped between the abutment step and the end wall of the installation cavity 32.

[0039] To facilitate the installation of the first elastic component 40, an installation cavity 32 can be provided inside the starting valve 30. The fourth end 22 of the spindle 20 can pass through the installation cavity 32 and slide to fit it. The first elastic component 40 is placed in the installation cavity 32 and abuts against the end wall of the installation cavity 32. In this way, the first elastic component 40 is installed in the installation cavity 32 of the starting valve 30. The first elastic component 40 can stably extend and retract within the installation cavity 32, and the elastic stress of the first elastic component 40 can also directly act on the starting valve 30. With stable elastic stress, the movement of the starting valve 30 is more stable, which facilitates better control of pressure changes.

[0040] Furthermore, a third through hole 73 can be provided at the first end, and a spray channel 107 can be provided in the body 1 of the expander. A nozzle is provided in the spray channel 107, and the third through hole 73 can communicate with the spray channel 107. The end of the movable rod away from the actuator is movably connected to the first flow channel and is used to close or open the third through hole.

[0041] When the blade is not extended and the actuator is not activated, the end of the movable rod 90 away from the brake is inserted into the first flow channel of the piston and closes the third through hole. At this time, the injection channel 107 is also in a non-conductive state.

[0042] As the actuator starts and drives the movable rod to move gradually toward the outlet end, the end of the movable rod that is connected to the piston will slide relative to the piston. After the blade 60 extends, in order to make the blade 60 work in the expanded state, the flow rate of the fluid pump can be increased. In this way, the pressure of the fluid introduced into the first flow channel 71 and the second flow channel 91 continues to increase, and the movable rod slides under the action of the actuator until it is misaligned with the third through hole.

[0043] During the eye-expanding state, as the fluid pressure in the first and second flow channels gradually increases, the fluid pressure in these channels continuously flows into the second guide flow channel 109 through the second through hole 92 and the first guide hole 83, pushing the piston's pusher towards the inlet end, thus maintaining the eye-expanding working state of the blade. Simultaneously, the fluid pressure in the first and second flow channels continuously acts on the actuator housing 10, pushing it to continue moving the movable rod 90 towards the outlet end. The second elastic component 50 is continuously compressed. When the second elastic component 50 is compressed to its limit, the portion of the movable rod 90 that passes through the piston can be misaligned with the third through hole 73. At this point, the fluid in the first flow channel 71 can flow through the third through hole 73 to the spray channel 107. The nozzle of the spray channel 107 guides the fluid to perform a mud-washing action on the eye-expanding blade, reducing mud residue on the blade 60 during the eye-expanding process and making the eye-expanding blade 60 operate more smoothly.

[0044] Furthermore, multiple first limiting grooves 74 can be provided on the outer wall of the first end, and a connecting block 61 can be provided on the blade 60 accordingly. When the blade 60 is assembled with the piston 70, the connecting block 61 can be assembled on the first end of the piston 70 by means of screws or bolts. The inner wall of the connecting block 61 is provided with multiple second limiting grooves. The connecting block 61 is connected to the first end so that the second limiting grooves mesh with the first limiting grooves 74. In this way, the meshing of the first limiting grooves 74 and the second limiting grooves limits the movement and prevents axial movement between the blade 60 and the piston 70. Thus, the connection structure between the piston 70 and the blade 60 is stable.

[0045] Furthermore, in this embodiment, the second through hole 92 is provided in three rows. The three rows of second through holes 92 are distributed at intervals in the axial direction of the movable rod 90. Since the second through hole 92 is provided in three rows, when the movable rod 90 moves relative to the guide sleeve 80 under different fluid pressures, the fluid flow direction can be switched by the second through hole 92 at different positions in the axial direction corresponding to the first guide hole 83 on the guide sleeve 80.

[0046] Of course, the second through hole 92 can also be set to a large diameter along the axial direction, so that when the movable rod 90 moves along the axial direction, the fluid flow direction can be switched through the second through hole 92 part connecting with the first guide hole 83.

[0047] Furthermore, the inner wall of the movable cavity 103 is provided with a first protruding step 105. The first protruding step 105 is provided on the inner wall of the movable cavity 103 near the inlet end 101. When the guide sleeve 80 is assembled into the movable cavity 103, a sealing structure can be provided on the end face of the first through section 85 of the guide sleeve 80 facing the outlet end. The sealing structure can seal and cooperate when the end face of the first through section abuts against the first protruding step.

[0048] In addition, a second protruding step is provided on the end face of the first connecting section facing the inlet end. The second protruding step and the push part are spaced to form the second guide flow channel. This facilitates the entry of fluid to form a certain fluid pressure in the second guide flow channel. The movement of the guide sleeve towards the outlet end is restricted by the first protruding step. The pressure in the second guide flow channel gradually increases. The fluid pressure acts on the second protruding step and is transmitted to the first protruding step. Under the action of fluid pressure, the sealing effect is better.

[0049] Furthermore, a limiting shaft 106 is inserted into the movable cavity 103. The limiting shaft 106 is used to abut against the blade 60 after the blade 60 moves close to the inner side of the reamer's opening. In this way, when an abnormal situation occurs during blade wing retrieval, a ball can be thrown to move the limiting shaft 106, along with the piston and blade, away from the inlet end 101, thus realizing the retrieval operation under abnormal blade wing conditions. The piston 70's movable rod 90 is mounted at the end of the limiting shaft 106, which can guide the axial movement of the piston 70. A guiding flow channel is provided in the limiting shaft 106, which is connected to the first flow channel 71. During fluid introduction, the fluid can be guided through the guiding flow channel, the first flow channel 71, and the second flow channel 91.

[0050] For those skilled in the art, various other corresponding changes and modifications can be made based on the technical solutions and concepts described above, and all such changes and modifications should fall within the protection scope of the claims of this invention.

Claims

1. An underreamer characterized by, The expansion reamer comprises an expansion reamer body, a blade, a piston, a guide assembly and an actuator. The expansion reamer body is provided with a movable cavity, an expansion opening, an inlet end and an outlet end. The blade is movably mounted on the expansion opening and can move towards or away from the expansion opening. The piston is mounted in the movable cavity and moves towards or away from the outlet end along the axial direction of the movable cavity. The piston is provided with a first end, a second end, a first flow channel and a first through hole. The first end is connected with the blade and guides the movement of the blade when moving along the axial direction of the movable cavity.

2. The reamer of claim 1, wherein, The outer wall of the second end is spaced from the inner wall of the movable cavity and forms a first guide flow channel. The end of the second end is provided with a pushing part which is in sealing sliding fit with the inner wall of the movable cavity. The first through hole is spaced from the pushing part along the axial direction of the movable cavity and guides the fluid into the first guide flow channel. The guide assembly comprises a guide sleeve, a movable rod and an actuator. The guide sleeve is provided with a first penetrating section, a first section, a second section and a second penetrating section. The outer wall of the first penetrating section is in sealing fit with the inner wall of the movable cavity. The first section and the second section are spaced from the inner wall of the movable cavity to form a second guide flow channel. The first section is provided with a first guide hole and the second section is provided with a second guide hole. The second penetrating section penetrates into the piston and is in sliding fit with the piston. The movable rod is provided with a second flow channel and a second through hole. The second flow channel is in communication with the first flow channel. The first guide hole is used to correspond to the second through hole to guide the fluid into the second guide channel. The second guide hole is used to correspond to the first through hole to guide the fluid into the first guide flow channel. The actuator is used to guide the movement of the movable rod according to the flow change of the second flow channel. The actuator comprises a housing, a first elastic member, a second elastic member and a driving part. The housing is provided with an inlet channel, an outlet channel and a cavity. The inlet channel is in communication with one end of the cavity. The outlet channel is in communication with the other end of the cavity. The inner peripheral wall of the cavity is provided with a closed part. The housing movably penetrates into the movable cavity and is connected with the movable rod. The inlet channel is in communication with the second flow channel. The second elastic member is clamped between the housing and the end wall of the outlet end. A valve body assembly, installed in the cavity, includes a spindle, a start valve, and a first elastic component. The spindle has a third end and a fourth end, the third end abutting against the end wall of the cavity. The outer peripheral wall of the third end is spaced from the inner peripheral wall of the cavity to form a first flow-guiding interval. The outer peripheral wall of the third end has a first through hole, and the third end has a through cavity, the first through hole communicating with the through cavity. The through cavity communicating with the outlet channel. The start valve is slidably installed on the fourth end and spaced from the inner peripheral wall of the cavity to form a second flow-guiding interval. The start valve is used to move closer to the closure under external force to block the second flow-guiding interval. The first elastic component provides an elastic stress that drives the start valve away from the closure. The start valve has a second through hole for connecting the inlet channel and the first flow-guiding interval.

3. The reamer of claim 2, wherein, The outer peripheral wall of the housing is provided with a first guide groove, a second guide groove, and a third guide groove. The first guide groove, the second guide groove, and the third guide groove all extend along the axial direction of the housing and are spaced apart in the circumferential direction of the housing. The first guide groove and the second guide groove are connected and communicate with each other through an inclined guide groove section. The second guide groove and the third guide groove are connected and communicate with each other through an inclined guide groove section. The first guide groove and the third guide groove are spaced apart from the second guide groove in the axial direction. The outer casing is rotatably fitted with a limiting sleeve, which is provided with a limiting post. The limiting post slides in conjunction with the first guide groove, the second guide groove, the third guide groove, and the inclined guide groove.

4. The reamer of claim 2, wherein, The start valve has an installation cavity, the fourth end passes through the installation cavity and slides into it; the first elastic member is located in the installation cavity and abuts against the end wall of the installation cavity; the fourth end has an abutment step, and the first elastic member is clamped between the abutment step and the end wall of the installation cavity.

5. The reamer of claim 2, wherein, The first end is provided with a third through hole; the eye expander body is provided with a spray channel; a nozzle is provided in the spray channel, and the third through hole is used to communicate with the spray channel; the end of the movable rod away from the actuator is movably connected to the first flow channel and is used to close or open the third through hole.

6. The reamer of any one of claims 1-5, wherein, The outer wall of the first end is provided with a plurality of first limiting tooth grooves; the blade is provided with a connecting block, the inner wall of the connecting block is provided with a plurality of second limiting tooth grooves, the connecting block is connected to the first end so that the second limiting tooth grooves mesh with the first limiting tooth grooves.

7. The reamer of any one of claims 1-5, wherein, The second through hole is provided in three rows, and the three rows of the second through hole are distributed at intervals along the axial direction of the movable rod.

8. The reamer of any one of claims 1-5, wherein, The inner wall of the movable cavity is provided with a first protruding step, which is located on the inner wall of the movable cavity near the inlet end. The first protruding step is sealed to the end face of the first through section of the guide sleeve facing the outlet end. The end face of the first through section facing the inlet end is provided with a second protruding step, which is spaced between the push-up parts to form the second guide flow channel.

9. The reamer of any of claims 1-5, wherein, The pushing part includes a pushing inclined surface that is arranged around the outer periphery of the second end of the piston.

10. The reamer of any one of claims 1-5, wherein, A limiting shaft passes through the movable cavity, and the limiting shaft is used to abut against the blade after the blade moves close to the inner side of the reamer. The piston rod is mounted on the end of the limiting shaft. The limiting shaft is provided with a flow channel, and the flow channel is connected to the first flow channel.

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