Self-centering rotary blowout preventer for tunnel surrounding rock drilling construction

Abstract

The application discloses a self-centering rotary blowout preventer for tunnel surrounding rock drilling construction and relates to the technical field of tunnel drilling construction. The self-centering rotary blowout preventer comprises a fixing assembly and a rotating assembly. The fixing assembly comprises a fixing pipe, a discharge pipe and a sleeve. One end of the sleeve is rotatably arranged in one end of the fixing pipe. The rotating assembly comprises a coaxially arranged connecting disc and a rubber sleeve. The large-diameter end of the rubber sleeve is fixedly connected with one end of the connecting disc. One end of a drill rod is connected with a drill bit after sequentially penetrating through the connecting disc and the rubber sleeve. The connecting disc is threadedly connected with the sleeve. The first sealing ring is arranged between the sleeve and the fixing pipe. The second sealing ring is arranged between the rubber sleeve and the sleeve. The sliding sealing effect between the rubber sleeve and the drill rod can effectively prevent underground water from being sprayed outwards along the axial direction of the drill hole during the whole drilling process. The fixing assembly further comprises a centering mechanism which constitutes a closed hydraulic system. The centering mechanism can realize the self-centering of the front end of the drill rod when the fixing assembly and the rotating assembly are connected, thereby ensuring the drilling quality.

Description

Technical Field

[0001] This invention relates to the field of tunnel drilling construction technology, specifically to a self-centering rotating blowout preventer for tunnel surrounding rock drilling construction. Background Technology

[0002] In tunnel engineering, anchor bolts are often used to stabilize and reinforce the surrounding rock. Before installing anchor bolts, drilling must be carried out at the locations where the anchor bolts will be installed within the surrounding rock. During tunnel anchoring construction, a large number of anchor bolt holes need to be drilled, and these holes are quite deep. However, the geological environment within the tunnel surrounding rock is complex, and groundwater seepage often occurs during drilling. This groundwater can spray out of the borehole opening, causing a significant impact on the construction environment and even forcing a work stoppage until the water is drained before construction can continue. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a self-centering rotating blowout preventer for drilling in tunnel surrounding rock. It is installed at the position corresponding to the borehole on the surrounding rock. If groundwater seepage is encountered during drilling, it can effectively prevent groundwater from spraying out, avoid affecting the construction environment, ensure the smooth progress of the drilling process, and provide centering support for the drill rod during drilling to ensure construction quality.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] A self-centering rotating blowout preventer for tunnel surrounding rock drilling includes a fixed component and a rotating component.

[0006] The fixing assembly includes a fixing pipe, a discharge pipe, a sleeve, and a centering mechanism. One end of the discharge pipe is fixedly connected to the side wall of the fixing pipe, and the discharge pipe communicates with the interior of the fixing pipe. One end of the sleeve is rotatably inserted into one end of the fixing pipe.

[0007] The centering mechanism includes an oil tank and several centering devices, which are evenly distributed circumferentially. Each centering device includes a centering cylinder closed at one end, which is arranged radially along the fixed tube. The open end of the centering cylinder passes through the outer wall of the fixed tube and is fixedly connected to it. A piston is slidably disposed inside the centering cylinder. A piston rod is fixedly connected to one end of the piston facing the fixed tube. A rodless cavity is formed between the other end of the piston and the closed end of the centering cylinder. A steel ball A is rotatably disposed on the piston rod facing the fixed tube. An installation device is located at the center of the oil tank. A rigid, closed box structure with holes is provided. The oil storage tank is fixedly sleeved on the fixed tube. The oil storage tank is located on the side of the centering device facing the sleeve. The rodless cavities of several centering tubes are all connected to the interior of the oil storage tank. Several plunger rods are evenly distributed in a circle on the side of the oil storage tank away from the centering device. The plunger rods are arranged along the axis parallel to the fixed tube. One end of the plunger rod is slidably disposed in the oil storage tank. A steel ball B is rotatably disposed on the other end of the plunger rod. A spring is sleeved on the plunger rod. The two ends of the spring are respectively connected to the outer wall of the oil storage tank and the plunger rod.

[0008] The rotating assembly includes a coaxially arranged connecting disc, a rubber sleeve, and an internally threaded sleeve. The connecting disc is annular, and the rubber sleeve is a hollow conical column. The large-diameter end of the rubber sleeve and one end of the internally threaded sleeve are both fixedly connected to the connecting disc. The internally threaded sleeve is threadedly connected to the end of the sleeve away from the fixed tube. The rubber sleeve is disposed inside the sleeve, and the end face of the connecting disc abuts against several of the steel balls B.

[0009] A first sealing ring is provided between the sleeve and the fixed tube, and a second sealing ring is provided between the rubber sleeve and the sleeve.

[0010] Preferably, it also includes a damping rubber sleeve, which is detachably connected to the fixing tube. The damping rubber sleeve has a friction hole at its center, and the damping rubber sleeve is fitted onto the sleeve through the friction hole, which is adapted to the sleeve.

[0011] Preferably, it also includes an electromagnetic coil, which is adapted to be mounted on the sleeve and is fixedly connected to the fixed tube.

[0012] Specifically, one end of the fixed tube is detachably connected to a bearing seat, the sleeve passes through the bearing seat, the sleeve and the bearing seat are connected by a bearing, and the first sealing ring is disposed between the sleeve and the bearing seat.

[0013] Specifically, the rotating assembly further includes a rigid connecting cylinder and a guide cylinder. The connecting cylinder is coaxially sleeved outside the guide cylinder. One end of the connecting cylinder and one end of the guide cylinder are fixedly connected to the connecting disc. The large-diameter end of the rubber sleeve is fixedly disposed between the connecting cylinder and the guide cylinder. The second sealing ring is disposed between the connecting cylinder and the sleeve.

[0014] Specifically, a flange is fixedly fitted onto the end of the fixed tube away from the sleeve.

[0015] Specifically, the oil storage tank is equipped with an oil injection pipe, and a valve is installed inside the oil injection pipe.

[0016] The beneficial effects of this invention are:

[0017] This self-centering rotating blowout preventer for tunnel surrounding rock drilling includes a fixed assembly and a rotating assembly. The fixed assembly includes a fixed pipe, a discharge pipe, and a sleeve. One end of the fixed pipe is fixed to the wall of the tunnel surrounding rock. The discharge pipe is connected to the side wall of the fixed pipe and can guide the discharge of slag and water. One end of the sleeve is rotatably inserted into the other end of the fixed pipe. The rotating assembly includes a coaxially arranged connecting disc, a rubber sleeve, and an internally threaded sleeve. The large-diameter end of the rubber sleeve and one end of the internally threaded sleeve are both fixedly connected to one end of the connecting disc. One end of the drill rod can pass through the connecting disc and the rubber sleeve in sequence and then connect to the drill bit. In use, the drilling equipment moves the drill rod to a position aligned with the axis of the fixed pipe, inserts the drill bit into the fixed pipe, and rotates the drill rod. This rotation drives the connecting disc to rotate along with the drill rod. During this rotation, the internally threaded sleeve can be threadedly connected to the end of the sleeve furthest from the fixed pipe. Subsequently, during the drilling process, the sleeve, rubber sleeve, and drill rod rotate together. A first sealing ring is installed between the sleeve and the fixed pipe, and a second sealing ring is installed between the rubber sleeve and the sleeve. Combined with the sliding sealing effect between the rubber sleeve and the drill rod, this effectively prevents groundwater from spraying outwards from the borehole opening along the borehole axis during the entire drilling process, avoiding its impact on the construction environment and ensuring the smooth progress of the drilling process. After drilling one hole, reversing the drill rod can separate the rotating component from the fixed component. The drilling equipment can then move the drill rod and the rotating component together to the next hole for drilling, making the operation relatively convenient.

[0018] The aforementioned fixing assembly also includes a centering mechanism, which comprises an oil reservoir and several centering devices evenly distributed circumferentially. Each centering device includes a centering cylinder, a piston, a piston rod, and steel ball A, with a structure similar to that of a hydraulic cylinder. Several plunger rods are evenly distributed circumferentially and slidably mounted on the oil reservoir. Springs are fitted onto the plunger rods to provide a restoring force. Steel ball B is located at the end of each plunger rod and abuts against a connecting disc. This centering mechanism constitutes a closed-loop hydraulic system. When the fixed and rotating components are connected during drilling, the drill rod tip can be self-centered to ensure drilling quality. When the drill bit needs to be removed after drilling, the fixed and rotating components are disengaged, allowing steel ball A and the piston rod to retract and avoid each other. The entire operation can be completed independently by the drilling equipment operator, making it relatively convenient. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the external structure of a self-centering rotating blowout preventer for tunnel surrounding rock drilling construction according to the present invention;

[0020] Figure 2 This is a cross-sectional structural schematic diagram of a self-centering rotating blowout preventer for tunnel surrounding rock drilling construction according to the present invention;

[0021] Figure 3 This is a schematic diagram of the exploded structure of a self-centering rotating blowout preventer for tunnel surrounding rock drilling construction according to the present invention;

[0022] In the diagram, 10-fixed component, 11-fixed pipe, 12-discharge pipe, 13-sleeve, 14-first sealing ring, 15-second sealing ring, 16-flange, 17-damping rubber sleeve, 18-bearing seat, 19-bearing, 20-rotating component, 21-connecting disc, 22-rubber sleeve, 23-internal threaded sleeve, 24-connecting cylinder, 25-guide cylinder, 30-centering mechanism, 31-oil reservoir, 32-centering cylinder, 33-piston, 34-piston rod, 35-steel ball A, 36-plunger rod, 37-spring, 38-steel ball B, 39-oil injection pipe. Detailed Implementation

[0023] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the following description.

[0024] like Figures 1 to 3As shown, a self-centering rotating blowout preventer for tunnel surrounding rock drilling includes a fixed assembly 10 and a rotating assembly 20. The fixed assembly 10 includes a fixed pipe 11, a discharge pipe 12, and a sleeve 13. One end of the discharge pipe 12 is fixedly connected to the side wall of the fixed pipe 11, and the discharge pipe 12 communicates internally with the fixed pipe 11. One end of the sleeve 13 is rotatably inserted into one end of the fixed pipe 11. The rotating assembly 20 includes a coaxially arranged connecting disc 21, a rubber sleeve 22, and an internally threaded sleeve 23. The connecting disc 21 is annular, and the rubber sleeve 22 is a hollow conical column. The large-diameter end of the rubber sleeve 22 and one end of the internally threaded sleeve 23 are both fixedly connected to the connecting disc 21. The internally threaded sleeve 23 is threadedly connected to the end of the sleeve 13 away from the fixed pipe 11, and the rubber sleeve 22 is disposed inside the sleeve 13. A first sealing ring 14 is provided between the sleeve 13 and the fixed pipe 11, and a second sealing ring 15 is provided between the rubber sleeve 22 and the sleeve 13.

[0025] During use, the fixed component 10 and the rotating component 20 are in a separate state for construction preparation:

[0026] Regarding the fixing component 10, the end of the fixing pipe 11 furthest from the sleeve 13 is fixedly installed on the surrounding rock wall of the tunnel (in specific implementation, a flange 16 is fixedly fitted onto this end of the fixing pipe and installed on the surrounding rock wall by bolts). During installation, the fixing pipe 11 is aligned with the axis of the borehole to be drilled. During drilling, the fixing component 10 can be installed at each borehole location where there is a risk of groundwater leakage.

[0027] The rotating assembly 20 is mounted on the drilling equipment. This equipment includes a carrier, a feed beam, a rock drill, drill rods, and a drill bit. The feed beam is mounted on the carrier and can be transported to any position and have its feed direction adjusted. The rock drill is slidably mounted on the feed beam. One end of the drill rod is connected to the output end of the rock drill, and the other end is connected to the drill bit. In the rotating assembly 20, the small-diameter end of the rubber sleeve 22 is matched to the diameter of the drill rod (the small-diameter end of the rubber sleeve 22 is chosen such that it can hold the drill rod to a certain extent, allowing them to slide relative to each other but making relative rotation difficult). Since its size is smaller than the drill bit diameter, one end of the drill rod needs to be inserted through the large-diameter end of the rubber sleeve 22 and then through the small-diameter end before connecting to the drill bit.

[0028] After completing the above construction preparations, drilling can be carried out. During construction, first operate the drilling equipment to align the drill bit with the axis of the fixed pipe 11, insert the drill bit into the fixed pipe 11 and rotate the drill rod. During this rotation, the connecting plate 21 and the internal threaded sleeve 23 will rotate under the drive of the rubber sleeve 22 until the threads of the internal threaded sleeve 23 and the sleeve 13 are tightened (if necessary, manual intervention is required during the tightening process, and the sleeve 13 is clamped and fixed using a clamping tool). After that, the drill rod, rubber sleeve 22, and sleeve 13 can rotate together to carry out drilling. Due to the first sealing ring 14, the second sealing ring 15, and the tight sealing effect between the flexible rubber sleeve 22 and the drill rod, even if groundwater is encountered during construction, it can be effectively prevented from spraying out from the end of the borehole. Instead, the groundwater and the drilling slag are discharged together under the guidance of the discharge pipe 12, thereby avoiding the impact on the construction environment and ensuring the smooth progress of the construction process. After drilling is completed, pull out the drill rod and reverse the drill rod so that the fixed component 10 and the rotating component 20 can be separated (manual intervention is required if necessary, and the sleeve 13 is clamped and slightly fixed using a clamping tool). Driven by the drilling equipment, the rotating component 20, along with the drill rod, drill bit, etc., moves to another construction hole position where the fixed component 10 is installed for drilling.

[0029] In the above design, the drill rod, sleeve 13, rubber sleeve 22 and connecting plate 21 rotate together during drilling. The second sealing ring 15 provides a static sealing environment, while the drill rod and rubber sleeve 22 only provide a sliding sealing environment when the drill rod is pushed forward. This design has low requirements for the sealing components, is easy to implement, and provides a reliable sealing effect.

[0030] The above methods effectively prevent groundwater from gushing outwards, avoiding impact on the construction environment and ensuring the smooth progress of drilling. However, because a fixed pipe 11 of a certain length is installed on the tunnel surrounding rock wall, the drilling equipment cannot be directly pressed against the tunnel surrounding rock wall to constrain and position the front end of the drill rod (the drill rod is only positioned by the connection of the rear rock drill, and its front rubber sleeve 22 is a flexible structure that cannot effectively position it). This makes it prone to axial displacement during drilling, affecting construction quality. Therefore, in addition to the above, a centering mechanism 30 is also provided.

[0031] The centering mechanism 30 includes an oil tank 31 and several centering devices. The centering devices are evenly distributed circumferentially. Each centering device includes a centering cylinder 32 with one end closed, positioned radially along the fixed pipe 11. The open end of the centering cylinder 32 passes through the outer wall of the fixed pipe 11 and is fixedly connected to it. A piston 33 is slidably disposed inside the centering cylinder 32. A piston rod 34 is fixedly connected to one end of the piston 33 facing the fixed pipe 11. A rodless cavity is formed between the other end of the piston 33 and the closed end of the centering cylinder 32. A steel ball A35 is rotatably disposed on the end of the piston rod 34 facing the fixed pipe 11. The oil tank 31 is a rigid, closed box structure with a central mounting hole. The oil tank 31 is fixedly sleeved on the fixed pipe 11 and positioned on the side of the centering device facing the sleeve 13. The rodless cavities of the several centering cylinders 32 are all connected to the interior of the oil tank 31. On the side of the oil reservoir 31 away from the centering device, several plunger rods 36 are evenly distributed in a circular pattern. The plunger rods 36 are arranged along the axis parallel to the fixed tube 11. One end of the plunger rod 36 is slidably disposed in the oil reservoir 31, and the other end of the plunger rod 36 is rotatably provided with a steel ball B38. A spring 37 is sleeved on the plunger rod 36. The two ends of the spring 37 are respectively connected to the outer wall of the oil reservoir 31 and the plunger rod 36. The end face of the connecting plate 21 abuts against the several steel balls B38.

[0032] The centering mechanism 30 forms a closed hydraulic system, with the oil reservoir 31 and the rodless chamber of the centering cylinder 32 filled with hydraulic oil. During the tightening of the threads of the aforementioned internal threaded sleeve 23 and sleeve 13, the connecting disc 21 rotates and moves towards the oil reservoir 31. The steel ball B38 pushes the plunger rod 36 into the oil reservoir 31. Since the oil reservoir 31 is a rigid closed structure with a constant internal volume, the plunger rod 36 occupies a certain volume after insertion, which squeezes the hydraulic oil to push each piston rod 34 out until the steel ball A35 at the end of the piston rod 34 presses against the drill rod. Since the rodless chamber of each centering cylinder 33 is connected to the inside of the oil reservoir 31, the pressing pressure of each piston rod 34 against the drill rod is consistent. In addition, the fixed tube 11 is fixedly installed, thus achieving centering and clamping of the front end of the drill rod. The rolling arrangement of the steel ball A35 will not hinder the rotation and sliding forward movement of the drill rod. When the drill bit needs to be removed, the internal threaded sleeve 23 is reversed and loosened from the sleeve 13. The connecting plate 21 moves away from the oil reservoir 31. Under the action of the spring 37, the plunger rod 36 is pushed outward, causing the piston rod 34 to retract within the centering cylinder 32, thus creating the space required to remove the drill bit. Therefore, through the above-mentioned design, when the fixed assembly 10 and the rotating assembly 20 are connected during drilling operations, the front end of the drill rod can be self-centered to ensure drilling quality. When the drill bit needs to be removed after drilling is completed, the steel ball A35 and the piston rod 34 can retract and avoid each other as the fixed assembly 10 and the rotating assembly 20 disengage. The entire operation is quite convenient.

[0033] In practical implementation, an oil filling pipe 39 is installed on the oil reservoir 31, and a valve is installed inside the oil filling pipe 39. When constructing the closed hydraulic system, first open the valve to press each plunger rod 36 to retract it to its maximum stroke within the oil reservoir 31; then inject hydraulic oil at a certain pressure into the oil reservoir through the oil filling pipe 39. When the reservoir is full, the pressurized oil will push the piston rod 34 to extend to its maximum stroke towards the center of the fixed pipe 11; then close the valve to release the pressure on each plunger rod 36. The plunger rod 36 will reset under the action of the spring 37, which will drive the piston rod 34 to retract, thus completing the construction of the closed hydraulic system.

[0034] During the aforementioned construction process, the tightening or loosening of the threads of the internal threaded sleeve 23 and the sleeve 13 often requires manual intervention to clamp and fix the sleeve 13. This makes it difficult for drilling equipment operators to complete the entire drilling process independently. Two solutions are proposed to address this issue:

[0035] One approach involves using a damping sleeve 17, which is detachably connected to the fixed tube 11. The damping sleeve 17 has a friction hole at its center, and it is fitted onto the sleeve 13 through this hole. The friction hole and sleeve 13 are compatible, providing a certain frictional resistance. This frictional resistance must be overcome for the sleeve 13 to rotate within the fixed tube 11. This frictional resistance provides a certain fixing force on the sleeve 13 during the aforementioned tightening or loosening of the threads, allowing the drilling equipment operator to operate independently. However, due to the significant relative rotation between the sleeve 13 and the fixed tube 11 during drilling, the damping sleeve 17 is prone to wear and has a short service life, generally requiring replacement only after a single use.

[0036] Another method is to set up an electromagnetic coil, which is adapted to be installed on the sleeve 13. The electromagnetic coil 13 is fixedly connected to the fixed pipe 11. The operator of the drilling equipment can remotely control the on and off of the electromagnetic coil to connect or disconnect the sleeve 13 from the fixed pipe 11.

[0037] In practical implementation, one end of the fixed pipe 11 is detachably connected to a bearing seat 18 via bolts. A sleeve 13 passes through the bearing seat 18, and the sleeve 13 and the bearing seat 18 are connected by a bearing 19. A first sealing ring 14 is disposed between the sleeve 13 and the bearing seat 18. The fixed pipe 11 and the bearing seat 18 are designed as a detachable structure. During drilling, only the fixed pipe 11 can be installed on the inner wall of the tunnel surrounding rock corresponding to each hole position, allowing the bearing seat 18 to be used alternately. In addition, the first sealing ring 14 is a dynamic seal. This split structure design also facilitates the inspection, replacement, and repair of the first sealing ring 14.

[0038] In specific implementation, the rotating assembly 20 also includes a rigid connecting cylinder 24 and a guide cylinder 25. The connecting cylinder 24 is coaxially sleeved outside the guide cylinder 25. One end of the connecting cylinder 24 and one end of the guide cylinder 25 are fixedly connected to the connecting plate 21. The large-diameter end of the rubber sleeve 22 is fixedly disposed between the connecting cylinder 24 and the guide cylinder 25 to achieve a fixed connection between the large-diameter end of the rubber sleeve 22 and the connecting plate 21, thereby increasing the overall rigidity of the large-diameter end of the rubber sleeve 22. The second sealing ring 15 is disposed between the connecting cylinder 24 and the sleeve 13, which are also rigid structures, thereby ensuring the sealing performance of the second sealing ring 15. The guide cylinder 25 passes through the large-diameter end of the rubber sleeve 22 and can guide the drill rod when it is inserted into the rubber sleeve 22, avoiding direct frictional contact between the drill rod and the flexible large-diameter end of the rubber sleeve 22.

[0039] The above description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the concept described herein through the above teachings or related technologies or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A self-centering rotary blowout preventer for tunnel surrounding rock drilling construction, characterized by, The fixed assembly and the rotating assembly are included, The fixed assembly includes a fixed tube, a discharge tube, a sleeve and a centering mechanism, one end of the discharge tube is fixedly connected with the side wall of the fixed tube, the discharge tube is in communication with the inside of the fixed tube, one end of the sleeve is rotatably arranged in one end of the fixed tube, The centering mechanism includes an oil storage tank and a plurality of centering devices, The plurality of centering devices are arranged in a circle, the centering device includes a centering cylinder with one end closed, the centering cylinder is arranged along the radial direction of the fixed tube, the open end of the centering cylinder penetrates the outer wall of the fixed tube and is fixedly connected with the fixed tube, a piston is slidably arranged in the centering cylinder, the piston is fixedly connected with a piston rod at one end thereof toward the fixed tube, a rodless cavity is formed between the other end of the piston and the closed end of the centering cylinder, the piston rod is rotatably provided with a steel ball A at one end thereof toward the fixed tube, The oil storage tank is a rigid closed box structure with a mounting hole in the center, the oil storage tank is fixedly sleeved on the fixed tube, the oil storage tank is arranged on the side of the centering device toward the sleeve, the rodless cavities of the plurality of centering cylinders are in communication with the inside of the oil storage tank, a plurality of plunger rods are arranged in a circle on the side of the oil storage tank away from the centering device, the plunger rods are arranged along the axis direction parallel to the fixed tube, one end of the plunger rod is slidably arranged in the oil storage tank, the other end of the plunger rod is rotatably provided with a steel ball B, a spring is sleeved on the plunger rod, and the two ends of the spring are connected with the outer wall of the oil storage tank and the plunger rod, respectively; The rotating assembly includes a coaxially arranged connecting disc, a rubber sleeve and an internally threaded sleeve, the connecting disc is in the shape of a ring, the rubber sleeve is in the shape of a hollow conical column, the large diameter end of the rubber sleeve and one end of the internally threaded sleeve are fixedly connected with the connecting disc, the internally threaded sleeve is threadedly connected with the end of the sleeve away from the fixed tube, the rubber sleeve is arranged in the sleeve, and the end face of the connecting disc abuts against the plurality of steel balls B; A first sealing ring is arranged between the sleeve and the fixed tube, and a second sealing ring is arranged between the rubber sleeve and the sleeve.

2. The self-centering swivel blowout preventer for tunnel surrounding rock drilling construction according to claim 1, characterized in that, A damping rubber sleeve is further included, the damping rubber sleeve is detachably connected with the fixed tube, a friction hole is arranged in the center of the damping rubber sleeve, the damping rubber sleeve is sleeved on the sleeve through the friction hole, and the friction hole is matched with the sleeve.

3. The self-centering swivel blowout preventer for tunnel surrounding rock drilling construction according to claim 1, characterized in that, An electromagnetic coil is further included, the electromagnetic coil is matched and sleeved on the sleeve, and the electromagnetic coil is fixedly connected with the fixed tube.

4. The self-centering swivel blowout preventer for tunnel surrounding rock drilling construction according to claim 1, characterized in that, One end of the fixed tube is detachably connected with a bearing seat, the sleeve is arranged in the bearing seat, the sleeve and the bearing seat are connected through a bearing, and the first sealing ring is arranged between the sleeve and the bearing seat.

5. The self-centering swivel blowout preventer for drilling construction of tunnel surrounding rock according to claim 1, characterized in that, The rotating assembly also includes a rigid connecting cylinder and a guide cylinder. The connecting cylinder is coaxially sleeved outside the guide cylinder. One end of the connecting cylinder and one end of the guide cylinder are fixedly connected to the connecting disc. The large-diameter end of the rubber sleeve is fixedly disposed between the connecting cylinder and the guide cylinder. The second sealing ring is disposed between the connecting cylinder and the sleeve.

6. The self-centering swivel blowout preventer for tunnel surrounding rock drilling construction according to claim 1, characterized in that, A flange is fixedly fitted onto the end of the fixed tube away from the sleeve.

7. The self-centering swivel blowout preventer for drilling construction of tunnel surrounding rock according to claim 1, characterized in that, The oil storage tank is equipped with an oil injection pipe, and a valve is installed inside the oil injection pipe.

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