CN216043608U

CN216043608U - Plugging mechanism of airtight core drill

Info

Publication number: CN216043608U
Application number: CN202122365071.XU
Authority: CN
Inventors: 陈晨; 王义红; 张坚
Original assignee: Shaanxi Taihe Intelligent Drilling Co ltd
Current assignee: Guizhou Taihe Intelligent Drilling Co ltd
Priority date: 2021-09-28
Filing date: 2021-09-28
Publication date: 2022-03-15
Anticipated expiration: 2031-09-28

Abstract

The utility model relates to the technical field of coal mine exploration, and discloses a plugging mechanism of a closed core drill, which comprises: drive mechanism and ball valve, drive mechanism sets up in the rock core pipe of drilling tool, the shell and the core pipe of ball valve link firmly, the rotation axis of ball valve is connected with driven gear, driven gear is connected with drive mechanism, thereby make driven gear drive the rotation axis produce the ball hole and the core pipe intercommunication that rotate messenger's ball valve, thereby realize when drilling state, the ball valve carries out the shutoff with the core pipe completely, make the intraductal sealed nothing miscellaneous state that reaches of core, drive ball valve through drive mechanism after reacing the sample position and rotate ball hole and core pipe intercommunication on messenger's ball valve, thereby it is intraductal to make the coal core get into the core from the trompil on the ball valve, it rotates realization core cutting and core pipe sealing function to drive the ball valve through drive mechanism once more.

Description

Plugging mechanism of airtight core drill

Technical Field

The utility model relates to the technical field of coal mine exploration, in particular to a plugging mechanism of a closed core drill.

Background

The determination of the content of the gas (coal bed gas) has great significance for mine ventilation, gas disaster control and coal bed gas resource development.

The prior gas content measuring method mainly comprises the steps of taking out a coal core through drilling, then loading the coal core into a cylinder for sealing, and then sending the coal core into a laboratory for measurement.

In order to solve the problem, a large amount of research work is carried out at home and abroad, and various pressure-relief closed coring devices special for coal mines are developed, and the pressure-relief closed coring devices comprise double-pipe pressure-relief coring drilling tools, triple-pipe pressure-relief coring drilling tools, coring drilling tools with closed liquid chambers and the like. Although the drilling tools consider plugging and sealing of the coal core in the coring process, the drilling tools have certain pertinence and practicability, but still have certain disadvantages: the plugging and cutting functions of the coal core are separated and completed by different mechanisms, and the sealing function is not realized in the sampling process; the sampled product is sealed by adopting a sealing liquid mode, so that the coring success is low and the cost is high.

SUMMERY OF THE UTILITY MODEL

The utility model provides a plugging mechanism of a closed core drill, which adopts a mechanical plugging mechanism to replace a closed liquid, solves the sealing problem in a drill hole and realizes the plugging and cutting functions of a coal core.

The utility model provides a plugging mechanism of a closed core drill, which comprises:

the transmission mechanism is arranged in a core tube of the drilling tool;

the shell of the ball valve is fixedly connected with the core tube, the rotating shaft of the ball valve is connected with a driven gear, and the driven gear is connected with a transmission mechanism, so that the driven gear drives the rotating shaft to rotate, and the ball hole of the ball valve is communicated with the core tube.

Optionally, the drill bit further comprises a stopper, the stopper is connected into the drill bit of the drilling tool through a shearing pin, the stopper extends out of the lower end face of the drill bit, the ball valve is located above the stopper, the outer diameter of the stopper is smaller than the aperture of the ball hole, and the stopper is aligned with the ball hole when the ball hole is communicated with the core barrel.

Optionally, a clamp spring seat is further fixed in the core tube, the clamp spring seat is fixedly connected with the shell of the ball valve, the lower portion of the clamp spring seat is provided with a taper, and a clamp spring is fixed in the clamp spring seat.

Optionally, the driven gear is located on the outer side of the housing, and a seal ring is connected between the end face of the driven gear and the outer milling plane of the housing.

Optionally, the transmission mechanism comprises:

the driving motor is arranged in the core tube;

the driving gear is connected with an output shaft of the driving motor;

and the rack is connected to the outer wall of the core tube in a sliding manner along the longitudinal direction of the core tube, is meshed with the driving gear, and is meshed with the driven gear.

Optionally, the outer wall of the core tube is fixed with a guide rib along the longitudinal direction of the core tube, the periphery of the core tube is sleeved with a sliding sleeve, the sliding sleeve is in sliding fit with the guide rib, and the rack is fixed on the sliding sleeve.

Optionally, the transmission mechanism further comprises:

the driving bevel gear is connected to an output shaft of the driving motor;

and the driven bevel gear is connected with the core tube through a gear shaft, the driven bevel gear is vertically meshed with the driving bevel gear, and the driving gear is connected to the part of the gear shaft extending out of the core tube.

Compared with the prior art, the utility model has the beneficial effects that: the utility model drives the ball valve to rotate through the transmission mechanism, thereby realizing that when in a drilling state, the core barrel is completely blocked by the ball body of the ball valve, the core barrel is in a sealed and impurity-free state, after reaching a sampling position, the ball valve is driven to rotate by 90 degrees through the transmission mechanism, so that the ball hole on the ball valve is communicated with the core barrel, thereby enabling a coal core to enter the core barrel through the sample inlet hole on the drill bit and the ball hole on the ball valve, and the mechanical sealing is used for driving the ball valve to rotate to realize the functions of cutting the core and blocking the core barrel.

Drawings

Fig. 1 is a schematic structural diagram of a plugging mechanism provided by an embodiment of the utility model when the plugging mechanism is used for a drilling tool;

FIG. 2 is an assembly view of a pinion and rack gear and a driven gear provided in accordance with an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a transmission mechanism according to an embodiment of the present invention;

fig. 4 is an enlarged view of a portion of the structure at G in fig. 1.

Description of reference numerals:

10-outer pipe, 11-drill bit, 12-baffle head, 13-upper joint, 14-flow channel, 15-diversion hole, 16-liquid outlet hole, 17-shear pin, 20-core pipe, 21-clamp spring seat, 22-clamp spring, 23-thimble valve, 24-through hole, 25-guide rib, 26-sliding sleeve, 30-transmission mechanism, 300-driving motor, 301-driving gear, 302-rack, 303-driving bevel gear, 304-driven bevel gear, 305-gear shaft, 306-gear box, 40-driven gear, 50-ball valve, 500-shell, 501-sealing ring group, 502-valve ball, 51-sealing ring, 52-centering bearing, 53-water tank, 60-electrical short joint, 600-short circuit shell, 601-connecting sleeve, 602-circuit sealing cover, 603-battery, 604-control board, 70-single-action mechanism, 700-thrust bearing, 701-bearing gland, 702-radial bearing and 703-locking nut.

Detailed Description

An embodiment of the present invention will be described in detail below with reference to the accompanying drawings, but it should be understood that the scope of the present invention is not limited to the embodiment.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of describing technical solutions of the present invention and simplifying the description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

Based on the above problems, the present invention provides a plugging mechanism for a closed core drill, which uses a mechanical closed core to replace a sealing fluid, and uses a mechanical seal to solve the sealing problem in a drill hole and simultaneously realize the plugging and cutting functions of a coal core, which is specifically described below with reference to the accompanying drawings, wherein fig. 1 is a schematic structural view when the plugging mechanism provided by the embodiment of the present invention is used in a drill, fig. 2 is an assembly view of a driving gear, a rack, and a driven gear provided by the embodiment of the present invention, fig. 3 is a schematic structural view of a transmission mechanism provided by the embodiment of the present invention, and fig. 4 is an enlarged schematic partial structure view at G in fig. 1.

As shown in fig. 1, a plugging mechanism for a closed core drill according to an embodiment of the present invention includes: the drill bit 11 is provided with a sample inlet hole which penetrates through the drill bit in the longitudinal direction, the transmission mechanism 30 is arranged in a core barrel 20 of the drilling tool, a shell 500 of the ball valve 50 is fixedly connected with the core barrel 20, a rotating shaft of the ball valve 50 is connected with a driven gear 40, and the driven gear 40 is connected with the transmission mechanism 30, so that the driven gear 40 drives the rotating shaft to rotate, and the ball hole of the ball valve 50 is communicated with the core barrel 20.

The utility model drives the ball valve to rotate through the transmission mechanism, thereby realizing that when in a drilling state, the core barrel is completely blocked by the ball body of the ball valve, the core barrel is in a sealed and impurity-free state, after reaching a sampling position, the ball valve is driven to rotate by 90 degrees through the transmission mechanism, so that the ball hole on the ball valve is communicated with the core barrel, thereby enabling a coal core to enter the core barrel through the sample inlet hole on the drill bit and the ball hole on the ball valve, and the mechanical sealing is used for driving the ball valve to rotate to realize the functions of cutting the core and blocking the core barrel.

Optionally, the drill bit further comprises a stopper 12, the stopper 12 is connected in the drill bit 11 of the drilling tool through a shear pin 17, the stopper 12 extends out of the lower end face of the drill bit 11, the ball valve 50 is located above the stopper 12, the outer diameter of the stopper 12 is smaller than the aperture of the ball hole, and the stopper 12 is aligned with the ball hole when the ball hole is communicated with the core barrel 20.

Optionally, a clamp spring seat 21 is further fixed in the core barrel 20, the clamp spring seat 21 is fixedly connected with the outer shell 500 of the ball valve 50, the lower portion of the clamp spring seat 21 has a taper, and a clamp spring 22 is fixed in the clamp spring seat 21.

Optionally, the driven gear 40 is located outside the housing 500, and a sealing ring 51 is connected between an end surface of the driven gear 40 and an outer milling plane of the housing 500.

Alternatively, the transmission mechanism 30 includes:

a driving motor 300 disposed in the core barrel 20;

a driving gear 301 connected to an output shaft of the driving motor 300;

and a rack 302 slidably coupled to an outer wall of the core barrel 20 in a longitudinal direction of the core barrel 20 and engaged with the pinion 301, and the driven gear 40 is engaged with the rack 302.

Optionally, a guide rib 25 is fixed on the outer wall of the core barrel 20 along the longitudinal direction thereof, a sliding sleeve 26 is sleeved on the periphery of the core barrel 20, the sliding sleeve 26 is in sliding fit with the guide rib 25, and the rack 302 is fixed on the sliding sleeve 26.

Optionally, the transmission mechanism 30 further includes:

a driving bevel gear 303 connected to an output shaft of the driving motor 300;

and a driven bevel gear 304 connected to the core barrel 20 through a gear shaft 305, the driven bevel gear 304 vertically engaged with the driving bevel gear 303, and the driving gear 301 connected to a portion of the gear shaft 305 extending out of the core barrel 20.

As shown in fig. 1 and 4, the plugging mechanism for a closed core drill according to an embodiment of the present invention is applied to a drill, including: the inner pipe assembly and the outer pipe assembly nested outside the inner pipe assembly, the outer pipe assembly is composed of an upper joint 13, an outer pipe 10 and a drill bit 11, the upper joint 13 is in a step shape with a larger upper diameter and a smaller lower diameter, the outer pipe 10 is in threaded connection with the upper part of the upper joint 13, the drill bit 11 is provided with a sample inlet hole penetrating through the drill bit 11 in the longitudinal direction, in the embodiment, the drill bit 11 adopts a step bottom spraying type structure form, the inner pipe assembly is composed of a single-acting mechanism 70, an electric short section 60, a core barrel 20 and a transmission mechanism 30, the transmission mechanism 30 is arranged in the core barrel 20, a shell 500 of the ball valve 50 is fixedly connected with the core barrel 20, a rotating shaft of the ball valve 50 is connected with a driven gear 40, the driven gear 40 is connected with the transmission mechanism 30, so that the driven gear 40 drives the rotating shaft to rotate, and the ball hole of the ball valve 50 is communicated with the core barrel 20, and the single-acting mechanism 70 is composed of a thrust bearing 701, a radial bearing 702 string, a bearing gland 701 and a bearing 701, The single-acting mechanism 70 is connected with a core tube 20 through a connecting sleeve 601, and is mainly characterized by large diameter and good rigidity, can bear the gravity of an inner tube when a horizontal hole is cored, and ensure concentricity, a thrust bearing 701 bears partial axial force caused by drilling pressure, a plurality of groups of radial bearings 702 can ensure concentricity, a gasket is added above a bearing gland 701 or between the locking nuts 703 to weakly adjust the axial gap between the front section of the inner tube assembly and a drill bit 11, an electric short section 60 comprises a control panel 604, a battery 603, a circuit sealing cover 602 and a short circuit shell 600, a transmission mechanism 30 is started through a control panel program to realize the rotation control of forward rotation or reverse rotation of a ball valve, the battery section comprises a plurality of groups of batteries, the short circuit has an explosion-proof function, the core tube 20 is connected with the lower part of an upper connector 13, a flow passage 14 is formed between the core tube 20 and an outer tube 10, a diversion hole 15 is arranged on the upper connector 13, the diversion hole 15 is communicated with the flow passage 14, so that flushing liquid flows into the flow passage 14, the drill bit 11 is provided with a liquid outlet hole 16, flushing liquid flows out through the liquid outlet hole 16, a bearing is arranged on a long guide column of the upper joint 13, the requirements on strength and concentricity are met, the outer pipe 10 bears torque and bit pressure, the drill bit 11 adopts a stepped bottom spraying type structural form, the coal core is prevented from being washed, the purpose of fast drilling is achieved, and the inner diameter of the drill bit 11 is smaller than the passing diameter of the ball valve 50.

Optionally, a stopper 12 is connected to the inside of the drill bit 11 through a shear pin 17, the stopper 12 extends out of the lower end surface of the drill bit 11, the ball valve 50 is located above the stopper 12, the outer diameter of the stopper 12 is smaller than the aperture of the ball hole, when the ball hole is communicated with the core barrel 20, the stopper 12 is aligned with the ball hole, because residue may exist in the horizontal bore, in order to prevent a large amount of residue from entering the core barrel 20 by running a drilling tool, the stopper 12 is designed, a seal ring and a shear small hole are arranged on the stopper 12, the pin hole on the stopper 12 and the pin hole on the drill bit 11 are connected through the shear pin 17 (wire pin), when the ball valve 50 is closed, the stopper 12 is ensured to be relatively stationary by virtue of the shear strength of the end surface of the ball valve 50 and the shear pin 17, when the ball valve 50 is opened and is subjected to the pressure of the drilling tool, the shear pin 17 is cut, the stopper 12 and the drill bit 11 move relatively, and enter the ball 502 and the core 20, and has the function of guiding the coal core.

Optionally, a clamp spring seat 21 is further fixed in the core barrel 20, the clamp spring seat 21 is fixedly connected with a housing 500 of the ball valve 50, the lower portion of the clamp spring seat 21 has a taper, a clamp spring 22 is fixed in the clamp spring seat 21, the ball valve 50 achieves a lower portion sealing function, the upper portion of the housing 500 of the ball valve 50 is connected with the core barrel 20 through an external thread, the lower portion of the housing 500 is connected with the clamp spring seat 21 through an internal thread, the diameter of the lower portion of the housing 500 is large, an upper seal ring, a ball body 502 and a lower seal ring of the ball body are sequentially arranged in the clamp spring seat 21 from the direction, the upper seal ring and the lower seal ring form a seal ring set 501, gaps between the ball body 502 and the seal ring set 501 are fixed and adjusted through screwing of the clamp spring seat 21, the seal rings are made of the same material, and achieve rotary sealing with the ball body 502. The trompil is gone up to the spheroid 502, inside the core coal got into core barrel 20 from the hole, spheroid 502 is connected on shell 500 by the rotation axis, one end is cylindrical rotation axis, the other end of spheroid 502 is interior, the welding rotation axis passes shell 500 and is connected with the outside driven gear 40 of spheroid 502 in the interior square, jump ring 22 is held on the one hand to jump ring seat 21, on the other hand is the compressing tightly mounting of subassembly in the ball valve 50, jump ring 21 lower part has 2 ~ 3 tapering, with the cooperation of jump ring 22, further supplementary ball valve 50 realizes the effect of card disconnected core coal.

In order to further ensure the air tightness, the driven gear 40 is positioned outside the shell 500, and a sealing ring 51 is connected between the end surface of the driven gear 40 and the outer milling plane of the shell 500.

It is optional, the bearing 52 of righting has been cup jointed between ball valve 50's shell 500 and drill bit 11, it has basin 53 to right to open on the bearing 52, basin 53 and circulation channel 14 intercommunication, because the drilling tool is mostly nearly horizontal coring, in order to ensure the concentricity and the single action nature of interior outer tube assembly, the bearing 52 of righting is equipped with to ball valve 50 anterior segment outside, this bearing outside has spline formula basin 53, be convenient for through the flush fluid, in order to ensure that the bearing rotates in a flexible way, the inside oily sliding pair (self-lubricating slide bearing inner frame promptly) that is of bearing.

Referring to fig. 2-3, the transmission mechanism 30 includes: the device comprises a driving motor 300, a gear box 306, a driving gear 301, a rack 302, a driving bevel gear 303 and a driven bevel gear 304, wherein the driving motor 300 is arranged and connected in a core barrel 20, the driving gear 301 is connected with an output shaft of the driving motor 300, the rack 302 is connected to the outer wall of the core barrel 20 in a sliding manner along the longitudinal direction of the core barrel 20 and is meshed with the driving gear 301, a driven gear 40 is meshed with the rack 302, the driving bevel gear 303 is connected to the output shaft of the driving motor 300, the driven bevel gear 304 is connected with the core barrel 20 through a gear shaft 305, the driven bevel gear 304 is vertically meshed with the driving bevel gear 303, the driving gear 301 is connected to a part of the gear shaft 305 extending out of the core barrel, a gear and rack mechanism is arranged outside the gear box 306, the gear box 306 is internally sealed and is not contacted with flushing liquid, the gear shaft 305 of the driven bevel gear 304 is connected with an external gear/rack, and the part is sealed with the outer end face of the gear box 306 through an end face sealing ring of the external gear, because the diameter is small, the rotating speed is low, and the sealing is easy to realize. Grease is filled in the gear box 306, the driving motor 300 is a low-voltage direct current motor or a stepping motor, rotation is started through a control board program, rotation control over the ball valve 50 can be achieved through forward rotation and overturning, and the circuit board program has the functions of timing, detecting rotation current, starting/stopping rotation and the like.

The transmission mechanism consists of an upper and a lower pair of gear rack structures and a sliding sleeve 26. The rack-and-pinion mechanism realizes the functions of changing rotation into linear motion and changing linear motion into rotation, the rotation of the driven gear 40 drives the lower ball valve 50 to rotate for 90 degrees for sealing and cutting a coal core, the sliding sleeve 26 slides outside the core tube 20, the core tube 20 is a sliding guide tube of the core tube, and meanwhile, the core tube 20 is provided with a guide rib 25, so that the sliding sleeve 26 can only slide up and down and can not rotate relatively, and the motion precision of the rack-and-pinion mechanism is guaranteed.

Optionally, the inner tube assembly further includes a needle ejection valve 23, a valve sleeve of the needle ejection valve 23 is fixedly connected with the upper end of the core tube 20, a through hole 24 is formed in the lower end of the needle ejection valve 23, the through hole 24 is communicated with the core tube 20, the core tube 20 mainly contains a coal core, the gear box 306 is connected with the electrical nipple 60 through a pin and a sealing ring in the upper portion of the core tube, a structure for vacuumizing and taking gas is designed on the upper portion of the core tube 20, the needle ejection valves with micro sealing rings are screwed in and out through the front portion and the rear portion of the needle ejection valve 23, and the core tube 20 is communicated with a vacuum machine or a gas sensor. When the drilling tool is ready for down-hole sampling, the ball valve 50 is closed, the through hole 24 is connected with the mechanical vacuum machine at the moment, air is extracted, the inside has a certain vacuum degree, the top needle valve 23 is closed, the vacuum machine is taken off, the influence of the external air of the drilling tool on the gas concentration pressure detection is overcome to the maximum extent, after the sampling is completed, the sampling is carried out, the gas detection sensor is connected, the inside is extracted in advance to be vacuum, the top needle valve 23 is opened again, and the gas in the core tube 20 enters the detection system to realize the detection of the gas parameter.

The use method and the working principle are as follows:

1. before the hole is drilled, firstly, a control program is written, the sealing opening time of the ball valve 50 is set, the inner pipe assembly is assembled, the ball valve 50 is closed, namely the ball hole is not communicated with the core pipe 20, the vacuum machine is connected with a tee joint (three through holes for vacuumizing and sampling), the needle-ejecting valve 23 is opened, vacuumizing treatment is carried out on the bin body, the needle-ejecting valve 23 is closed after a certain vacuum degree is reached, and at the moment, the interior of the core pipe 20 is vacuum.

2. The inner pipe assembly is assembled with the single action device 70, and the drill bit 11, the stopper 12 and other parts are assembled to wait for the sampling of the drilling tool.

3. A sealed drilling tool is put in through a drilling machine, the drilling tool is fed while water is introduced, the ball valve 50 is closed, meanwhile, the special double-ball-head retaining head 12 blocks the center hole of the drilling tool and blocks front coal cinder, the front part of the ball valve 50 of the drilling tool is in a cinder-free clean state at the moment, and flushing liquid washes a drilled hole from a bottom spray hole of the bottom spray drill bit 11 to finish hole cleaning operation.

4. And (3) when the drilling tool is lowered to the hole bottom drilling position, the driving motor 300 is started according to the set time, the ball valve 50 is opened, the drilling tool is pressurized, the bottom coal seam forces the shearing pin 17 to be sheared under pressure (the ball valve 50 loses the jacking force effect) under the feeding force, the core drilling is normally carried out, and the stopper 12 and the coal sample sequentially enter the core barrel 20.

5. After the coal sample is fully sampled, the drilling tool is slightly lifted away from the bottom of the hole, the coal core is blocked by the clamp spring 22, and the ball valve 50 is waited to be closed.

6. When the closing time of the ball valve 50 in the program is up, the ball valve 50 rotates, the ball valve 50 extrudes the coal core, the front coal core is cut by the cutting edge of the ball valve 50 through repeated twisting and rotation of the driving motor 300 until the ball valve 50 is completely closed (the closing of the ball valve is detected), and the closed sampling is completed.

7. And (3) lifting the drilling tool, connecting the gas pressure and concentration sensor to the tee joint (through hole 24), extracting air in the test pipeline, opening the thimble valve 23, and allowing gas to enter the sensing system to finish the test of the gas content and pressure.

The closed core drilling tool provided by the utility model has the following advantages:

(1) the thrust bearing is adopted to bear the axial force caused by partial drilling pressure, and the plurality of groups of radial bearings and the centralizing bearing are adopted to play a role in linkage, so that the coaxiality of the inner and outer pipe assemblies is ensured in the nearly horizontal hole, and the rock core can smoothly enter the rock core pipe.

(2) A top needle valve is reserved on the upper portion of the rock core pipe and used for vacuumizing and gas detection, whole-process closed gas detection is achieved, and external air interference is avoided to the maximum extent.

(3) Utilize electric nipple joint drive airtight ball valve to realize the cutting of rock core and the sealed function of rock core pipe, add the entry stop simultaneously, prevent that the residue from getting into the rock core pipe, both improved airtight coring's success rate, guaranteed the pure nature of rock core again.

The above disclosure is only for a few specific embodiments of the present invention, however, the present invention is not limited to the above embodiments, and any variations that can be made by those skilled in the art are intended to fall within the scope of the present invention.

Claims

1. The utility model provides a shutoff mechanism of airtight core drill, its characterized in that includes:

the transmission mechanism (30) is arranged in a core tube (20) of the drilling tool;

ball valve (50), shell (500) with core barrel (20) link firmly, the rotation axis of ball valve (50) is connected with driven gear (40), driven gear (40) with drive mechanism (30) are connected, thereby make driven gear (40) drive the rotation axis produces the rotation and makes the bulb hole of ball valve (50) with core barrel (20) intercommunication.

2. The plugging mechanism of a closed core drill as set forth in claim 1, further comprising a stopper (12), said stopper (12) being connected to the inside of the drill bit (11) of said drill by a shear pin (17), said stopper (12) extending out of the lower end surface of said drill bit (11), said ball valve (50) being located above said stopper (12), said stopper (12) having an outer diameter smaller than the diameter of said ball hole, said stopper (12) facing said ball hole when said ball hole is in communication with said core barrel (20).

3. The plugging mechanism of the closed core drill as recited in claim 1, wherein a clamp spring seat (21) is further fixed in the core barrel (20), the clamp spring seat (21) is fixedly connected with a shell (500) of the ball valve (50), the lower part of the clamp spring seat (21) has a taper, and a clamp spring (22) is fixed in the clamp spring seat (21).

4. The plugging mechanism of a closed core drill as set forth in claim 1, wherein said driven gear (40) is located outside said housing (500), and a seal ring (51) is connected between an end surface of said driven gear (40) and an outer milling surface of said housing (500).

5. The plugging mechanism of a closed core drill according to claim 1, wherein said transmission mechanism (30) comprises:

a drive motor (300) disposed within the core barrel (20);

a drive gear (301) connected to an output shaft of the drive motor (300);

and a rack (302) which is slidably connected to the outer wall of the core barrel (20) in the longitudinal direction of the core barrel (20) and is engaged with the driving gear (301), and the driven gear (40) is engaged with the rack (302).

6. The plugging mechanism of a closed core drill as set forth in claim 5, wherein a guide rib (25) is fixed to an outer wall of the core barrel (20) in a longitudinal direction thereof, a sliding sleeve (26) is fitted around an outer periphery of the core barrel (20), the sliding sleeve (26) is slidably fitted over the guide rib (25), and the rack (302) is fixed to the sliding sleeve (26).

7. The plugging mechanism of a closed core drill according to claim 6, wherein said transmission mechanism (30) further comprises:

a driving bevel gear (303) connected to an output shaft of the driving motor (300);

a driven bevel gear (304) connected to the core tube (20) through a gear shaft (305), the driven bevel gear (304) vertically engaged with the driving bevel gear (303), and the driving gear (301) connected to a portion of the gear shaft (305) extending out of the core tube (20).