CN210370499U

CN210370499U - Centrifugal pipe following drilling tool

Info

Publication number: CN210370499U
Application number: CN201920868296.7U
Authority: CN
Inventors: 马勇; 曾德明; 胡小龙
Original assignee: Guanghan Copry Technology Co ltd
Current assignee: Guanghan Copry Technology Co ltd
Priority date: 2019-06-11
Filing date: 2019-06-11
Publication date: 2020-04-21
Anticipated expiration: 2029-06-11

Abstract

The utility model discloses a drilling tool, in particular to a centrifugal pipe following drilling tool, belonging to the technical field of drilling devices; the device comprises a transmission shaft, a hole opener and hole enlarging blocks, wherein the number of the hole enlarging blocks is at least 2, an arc-shaped groove is formed in each hole enlarging block, an arc-shaped block is arranged at the top of the transmission shaft, so that the arc-shaped blocks are assembled on the arc-shaped grooves, the arc-shaped end of each arc-shaped block is located at the center of the transmission shaft, and the hole enlarging blocks realize expansion/contraction through the arc-shaped grooves and the arc-shaped blocks; the utility model provides a traditional pipe drilling tool if will change the problem that then need change this drilling tool in the use, the practicality that can effectual improvement drilling tool through the design of split type structure to can change the effect that the hole digger can according to the wearing and tearing condition of hole digger, thereby the effectual maintenance cost that reduces the drilling tool also can improve the maintenance efficiency of drilling tool.

Description

Centrifugal pipe following drilling tool

Technical Field

The utility model relates to a drilling tool, especially a centrifugal pipe drilling tool that follows belongs to drilling equipment technical field.

Background

The existing concentric or eccentric casing following drilling tools select different drilling tools according to different geological conditions, and meanwhile, the existing casing following drilling tools have overlarge torque force and easily broken reaming sheets in the drilling process, so that the reliability of the drilling tools is reduced; meanwhile, in the process of drilling in a sand flowing layer by using a common drilling tool, because the air hole of the drilling tool is communicated with the air hole of the impactor, when a drilling rod, a sleeve and air are added and closed, the flowing sand in the hole flows back into the impactor, so that the impactor does not work, and the construction progress is influenced.

Disclosure of Invention

The invention of the utility model aims to: to the problem that above-mentioned exists, provide a centrifugal pipe drilling tool, this centrifugal pipe drilling tool that follows possesses the practicality strong, can only need to change the hole digger, solves the problem of changing whole device because of wearing and tearing.

The utility model adopts the technical scheme as follows:

a centrifugal type pipe-following drilling tool comprises a transmission shaft, a hole digger and a hole enlarging block;

wherein, the reaming blocks have at least 2, the reaming block is provided with an arc-shaped groove, the top of the transmission shaft is provided with an arc-shaped block, so that the arc-shaped block is assembled on the arc-shaped groove, the arc-shaped end of the arc-shaped block is positioned at the center of the transmission shaft, and the reaming block realizes expansion/contraction through the arc-shaped groove and the arc-shaped block;

the side of the hole digger is also provided with an assembly hole for assembling the hole enlarging block, and the transmission shaft can be assembled in the shaft hole of the hole digger and can realize the sliding of the hole enlarging block in the assembly hole through the arc-shaped groove and the arc-shaped block.

The utility model discloses a centrifugal pipe-following drilling tool passes through split type structural design, makes axis of rotation and hole digger form two independent structural design, and in following the pipe well drilling technology, because long-term use, the hole digger can cause more serious wearing and tearing, only changes whole drilling tool under the condition that the wearing and tearing transition can not be used, and this problem of effectual having solved of this design, only need to change the change that the hole digger can accomplish the drilling tool, the effectual cost that reduces the drilling tool.

Furthermore, the lower part of transmission shaft is provided with a plurality of guide ways that are used for the assembly location, and the upper portion of hole digger inside wall is provided with the gib block that matches with the guide way. This mode can effectively assist the assembly between transmission shaft and the hole digger.

Furthermore, a limiting groove is further arranged above the guide groove, the width of the limiting groove is larger than that of the guide groove, and the transmission shaft is assembled in the hole digger and then enables the bottom edge of the guide groove to be matched with the bottom edge of the guide strip to realize limiting through rotation. The design mode can realize the limit of assembly and ensure the stability of the assembly.

Furthermore, the guide way side still is provided with the constant head tank, and the one end intercommunication guide way of this constant head tank, and the top side of this constant head tank is less than the base of spacing groove, and this spacing groove and constant head tank intercommunication, the guide way is interior to be assembled in the constant head tank and move to the position of guide way so that realize the positioning. The design of this mode can effectually solve the tradition and adopted the pin location problem that the lifting surface area is little, more possess stability.

Furthermore, the length of the arc key along the circumferential direction is longer than the width of the guide groove so as to realize the installation effect of the arc key, and a pin hole used for assembling the arc key in the positioning groove to move is arranged at the position corresponding to the side wall of the hole digger.

Furthermore, the positioning device also comprises a position occupying pin for avoiding the sliding of the arc key, wherein the position occupying pin is assembled in the positioning groove through a pin hole so as to realize the positioning of the arc key, and is assembled in the pin hole through an expansion pin. This mode can effectively guarantee the assembly positioning effect of arc key.

Further, this transmission shaft bottom is provided with the venthole, and the top of this transmission shaft still is provided with the inlet port, and this inlet port forms the air flue with the venthole intercommunication, and the bottom of hole digger still is provided with a plurality of fumaroles, and is opened/closed with control fumarole through the flexible of reaming piece to the gaseous high-pressure gas or the liquid that pass through fumarole blowout and restriction external environment of realization venthole flow backward. The design of this mode can effectual assurance admit air and prevent the palirrhea problem of gas or liquid.

Further, still be provided with on this transmission shaft and be used for with hole digger terminal surface complex assembly stopper, this assembly stopper and hole digger terminal surface are hard to be cooperated in order to realize that the assembly is spacing and realize sealed and transmit and assault.

Furthermore, the number of the reaming blocks is three, the bottom surfaces of the three reaming blocks form a complete plane in a closed state, the number of the arc-shaped blocks is three, and the other arc-shaped ends of the arc-shaped blocks extend to the side wall of the transmission shaft.

To sum up, owing to adopted above-mentioned technical scheme, the beneficial effects of the utility model are that:

1. the utility model discloses a centrifugal pipe following drilling tool solves the problem that if the traditional pipe following drilling tool needs to be replaced in the using process, the drilling tool needs to be replaced, the practicability of the drilling tool can be effectively improved through the design of a split type structure, and the effect that the hole digger can be replaced according to the abrasion condition of the hole digger, thereby effectively reducing the maintenance cost of the drilling tool and also improving the maintenance efficiency of the drilling tool;

2. this design combines the design of split type structure and the design of reaming piece can effectually solve deep hole, groundwater back pressure silt and get into drilling tool or impacter and cause the problem of downthehole accident, and when drilling tool reaming normally bored, as conventional drilling tool, the accessible drilling tool bottom gas pocket blows off the dregs, and the while is still effectual to have solved the interior dregs of drilling tool and has blown off the problem of arranging not to the utmost.

Drawings

Fig. 1 is a schematic structural diagram of the present invention;

FIG. 2 is a schematic view of the expanding structure of the assembled reamer blocks of the present invention;

FIG. 3 is a schematic view of the contracting structure of the assembled reamer blocks of the present invention;

FIG. 4 is a top view of the reamer block in an extended state fitted within the mounting hole of the hole cutter;

FIG. 5 is a top view of the reamer block shown in a retracted state as it is fitted within the mounting hole of the hole cutter;

FIG. 6 is a schematic structural diagram of a top view of the drive shaft;

FIG. 7 is a schematic structural view of a bottom view of the drive shaft;

FIG. 8 is a schematic diagram of a top view of the hole cutter;

fig. 9 is a schematic structural view of the hole cutter;

FIG. 10 is a schematic view of the underreamer;

fig. 11 is a schematic structural view of the present invention with the reaming block assembled on the transmission shaft;

fig. 12 is a top view of the application of the invention;

fig. 13 is a schematic cross-sectional view of the present invention;

fig. 14 is a schematic structural view of the impact pin for disassembly according to the present invention;

fig. 15 is a schematic cross-sectional structure of fig. 14.

The labels in the figure are: 1-transmission shaft, 11-arc block, 12-guide groove, 13-limit groove, 14-positioning groove, 15-limit block, 16-arc surface, 2-hole opener, 21-assembly hole, 22-guide strip, 23-pin hole, 3-hole expanding block, 31-arc groove, 4-arc key, 5-position occupying pin, 6-air inlet hole, 7-air outlet hole, 8-air jet hole, 9-expansion pin and 10-impact pin.

Detailed Description

The present invention will be described in detail with reference to the accompanying drawings.

In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Example 1

A centrifugal type pipe-following drilling tool, as shown in fig. 1 to 11, comprising a transmission shaft 1, a hole opener 2 and a hole-expanding block 3;

wherein, the reaming blocks 3 have at least 2, there are arc-shaped grooves 31 on the reaming block 3, the top of the drive shaft 1 has arc-shaped blocks 11, so that the arc-shaped blocks are assembled on the arc-shaped grooves, the arc-shaped end of the arc-shaped block is located in the center of the drive shaft, the reaming block 3 realizes expansion/contraction through the arc-shaped grooves 31 and the arc-shaped blocks 11;

the side surface of the hole digger is also provided with an assembling hole 21 for assembling the hole enlarging block 3, and the transmission shaft can be assembled in the shaft hole of the hole digger and can realize the sliding of the hole enlarging block in the assembling hole through the arc-shaped groove 31 and the arc-shaped block 11.

In this embodiment, can effectively realize the expansion/shrink of reaming piece through arc wall 31 and arc piece 11 and the design of arc wall 31, because the design of arc piece, arc wall 31 makes the reaming piece receive inside/outside power, makes the reaming piece can realize the arc motion along the arc piece on the arc piece, because the design of arc direction, makes the distance that reaming piece put relative transmission shaft central point and changes to the effectual opening and shutting that realizes the reaming piece. In addition, transmission shaft and hole digger are detachable structure's design to realize that these two structures are independent device, through this design can effectually realize the drilling tool wearing and tearing only need change the effect of hole digger under the great condition of realization drilling wearing and tearing.

In principle, in order to ensure that the transmission shaft is assembled with the hole cutter to enable better positioning, in another embodiment, the lower part of the transmission shaft 1 is provided with a plurality of guide grooves 12 for assembling and positioning, and the upper part of the inner side wall of the hole cutter 2 is provided with a guide strip 22 matched with the guide grooves. Design through this mode can be effectual make the more accurate assembly of transmission shaft to the hole digger in and cooperate with the reaming piece.

Based on the design of the assembly structure, in one specific embodiment, a limiting groove 13 is further arranged above the guide groove 12, the width of the limiting groove is larger than that of the guide groove, and the transmission shaft is assembled in the hole digger and then is rotated to enable the bottom edge of the guide groove to be matched with the bottom edge of the guide strip to realize limiting. In the specific operation, the guide strip and the guide groove are dislocated through the rotation of the transmission shaft, and the bottom of the limiting groove 13 is matched with the bottom of the guide strip to realize limiting assembly. Specifically, the distance between the bottom surface of the limiting groove 13 and the bottom surface of the guide strip is not more than 1.5 mm. In addition, in the specific design, the position of the circle center of the arc block relative to the arc and the position of the limiting groove 13 in the width extension direction relative to the guide groove are in the same direction, and the expanding block is opened in the rotating process of the transmission shaft through the design. More specifically, taking the figure as an example, when viewed from bottom to top, the extending direction of the limiting groove is counterclockwise, and the center of the arc block is located on one side of the counterclockwise direction of the arc. In this case, the bottom surface of the stopper groove 13 is flush with the top surface of the guide groove.

As a more specific design, in one specific embodiment, the side edge of the guide groove is further provided with a positioning groove 14, one end of the positioning groove is communicated with the guide groove, the top side edge of the positioning groove is lower than the bottom edge of the limiting groove, the limiting groove is communicated with the positioning groove, and the inside of the guide groove is assembled in the positioning groove by arranging an arc-shaped key 4 and moved to the position of the guide groove so as to realize the assembling positioning. As a more specific design, the depth of the positioning groove is deeper than the depth of the positioning groove. One side of the positioning groove with the guide groove extends to the other side of the guide groove along the circumferential direction.

In another embodiment, in combination with the design of the above embodiment, the length of the arced key 4 in the circumferential direction is longer than the width of the guide slot to achieve the arced key installation effect, and the corresponding position of the side wall of the hole cutter 2 is provided with a pin hole 23 for the arced key to move in the positioning slot. In this embodiment, in actual assembly, this arced key 4 assembles earlier in the constant head tank, assembles the back with the transmission shaft in the hole digger after the assembly, after the assembly targets in place, can have the removal of arced key in the constant head tank through the design of pinhole 23 to realize spacing effect, thereby perhaps realize removing the matching that thereby messenger gib block and guide way can be smooth and easy with the help of the design of this pinhole when needing to take out the transmission shaft.

Among the above-mentioned embodiment, on the design basis that does not have the arc key, the cooperation of the bottom terminal surface of lateral wall top terminal surface of guide way and gib block after this transmission shaft rotates keeps the wholeness of drilling tool, and can effectively guarantee the reaming piece and still keep the wholeness of whole pipe following drilling tool after retrieving as the design of arc key and constant head tank, can not appear promoting the condition that transmission shaft and hole digger drop.

In order to further ensure the stability of the arc key in the positioning groove and avoid the looseness, in another specific embodiment, the positioning groove further comprises a position occupying pin 5 for avoiding the sliding of the arc key, wherein the position occupying pin is assembled in the positioning groove through a pin hole so as to realize the positioning of the arc key, and is assembled in the pin hole through an expansion pin 9. And the number of the occupation pins 5 is generally two. Thereby can effectually make occupation of a position round pin and arced key fill in the constant head tank relatively, even have slight swing, do not influence the limiting displacement of arced key yet. The pin hole is well assembled in the occupying position, and in order to guarantee the assembling effect, the pin hole is sealed by adopting an expansion pin. In a specific design, the positioning groove and the limiting groove extend in opposite directions of the circumference by taking the guide groove as a reference. Specifically, the space occupying pin is 2 steel balls.

Based on above-mentioned embodiment's design principle, in one of them embodiment, this transmission shaft bottom is provided with venthole 7, and the top of this transmission shaft still is provided with inlet port 6, and this inlet port forms the air flue with the venthole intercommunication, and the bottom of hole digger still is provided with a plurality of fumaroles 8, and is opened/closed in order to control the fumarole through the flexible of reaming piece to realize that the gas of venthole passes through fumarole blowout and restriction external environment's high-pressure gas or liquid are palirrhea. In this design, because the design of reaming piece slidable, especially in the condition of shrink, this reaming piece can block the second venthole, can effectually avoid external environment's high-pressure gas or liquid palirrhea.

In the assembly, as a more specific design, in another specific embodiment, an assembly limiting block 15 for matching with the end surface of the hole cutter is further arranged on the transmission shaft 1, and the assembly limiting block is in hard matching with the end surface of the hole cutter to realize assembly limiting and realize sealing and impact transmission. As can be clearly seen from the drawings, the stopper 15 is a cylinder, and the bottom surface of the stopper is matched with the top surface of the hole opener. After the assembly, the bottom surface of the limiting block is contacted with the top surface of the hole digger, and the arc-shaped block below the transmission shaft is positioned in the arc-shaped groove of the hole enlarging block.

In the structural design of the reaming blocks, in one specific embodiment, the number of the reaming blocks is three, the bottom surfaces of the three reaming blocks form a complete plane in a closed state, the number of the arc-shaped blocks is three, and the arc-shaped other ends of the arc-shaped blocks extend to the side wall of the transmission shaft. As a more specific example, to further realize the operation, it is specifically described here that the 3 pieces of the reamer blocks are distributed in a circumferential array as shown in the drawing. Specifically, the major shape of this reaming piece is for having the top plane to and the transition face that the slope set up, the cambered surface in the outside, and the inboard of this reaming piece is provided with the arc wall, and the arc length of this arc wall is less than the arc length of arc piece in order to realize gliding effect. More specifically, the hole expanding block is further provided with an air hole penetrating through the hole expanding block, one end of the air hole is located in the arc-shaped groove, and the other end of the air hole is located on the bottom surface of the hole expanding block.

In a more specific design, the hard alloy blocks are arranged on the outer side of the hole expanding block and the bottom surface of the hole opener. As a more specific design, the transmission shaft is integrally formed, and the structure of the transmission shaft is formed by lathing.

More specifically, because the quantity design of reaming piece, consequently the design of arc piece is 3, and in addition, the quantity of venthole 7 also is 3, and every venthole is located respectively between two adjacent arc pieces and is close to the central point of transmission shaft and puts. Of course, the arc-shaped blocks may be 4, 5 or 6 as a design application. The specific design mode is circumferential array distribution. In a specific design, the hole expanding block is also provided with an arc-shaped surface 16 for improving the assembly effect.

In principle, the tapping device 2 is provided with a locking platform matching with the pipe body on the periphery as shown in fig. 12 and 13 for specific application. It can be seen from the figure that the structure of the tubular body matches the structural design of the drilling tool. The design mode is combined with the design scheme, and the design scheme can be smoothly opened and recovered in any stratum.

In addition, in order to facilitate the disassembly of the drill, as shown in fig. 14 and 15, the hole cutter 2 and the rotary shaft are provided with through holes coaxial with the pin holes to facilitate the assembly of the punch pin 10. When the hole expanding block is in a contraction state, the punching pin can penetrate through the drilling tool, so that the occupation pin can be taken out of the pin hole.

As a specific description, in particular, for the convenience of understanding, the positional relationship described in the above embodiments is described in the working form of the casing drilling tool, and the schematic structure and the description direction are inverted from each other in terms of the structure of the drawings.

Based on the design of the above-mentioned embodiments, in this embodiment, as the assembly and use thereof, the drive shaft manufactured and molded is assembled into the shaft hole of the hole cutter through the guide groove and the guide strip, the shaft hole is designed by taking the hole digger as a side wall and having a bottom side wall, the side wall of the hole digger is provided with an assembly hole, the reaming block is assembled in the assembly hole in advance and takes a contraction state as an initial state, the arc-shaped key is assembled in advance before the transmission shaft is assembled into the hole digger and assembled into the hole digger after transmission, the arc block is matched in the arc groove, the transmission shaft is rotated anticlockwise, the hole enlarging block is extended out of the assembling hole of the hole opener, the positions of the arc keys are adjusted through the pin holes, the occupied position pins are added for positioning, then the pin holes are sealed by the expansion pins, because the arc-shaped block and the arc-shaped groove are assembled to the limit position, the hole digger is driven to rotate. In the operation process, air is supplied through the air inlet holes and is discharged through the air outlet holes, and in the unfolding state, the air can be blown out through the air spraying holes, so that the drilling effect is effectively realized. And under certain circumstances, in order to avoid high-pressure gas or liquid to flow backward, clockwise rotation transmission shaft realizes the shrink of reaming piece, can close the fumarole after the shrink, and effectual high-pressure gas or liquid of having avoided flow backward. Simultaneously, can lift the transmission shaft, because the spacing of fit-up gap and arc key realizes that the trace promotes, can make the gas that comes out from the venthole upwards blow, effectively clear up the impurity in the pipe-following drilling tool. Of these, it must be noted that after the reamer blocks are expanded, the gas orifices are not blocked by the maximum expansion of the reamer blocks and are closed after contraction.

Example 2

A method of a centrifugal casing drilling tool, comprising the steps of:

a. the hole digger is used for processing a guide strip on the upper part of the inner side wall of the hole digger, and the bottom of the hole digger is provided with an assembling hole for assembling a hole enlarging block and a pin hole for moving an arc-shaped key;

b. the inner side of the reaming block is provided with an arc-shaped groove, and the reaming block is assembled in an assembling hole of the hole opener and is in a contracted state;

c. the outer side wall of the transmission shaft is provided with a guide groove, the bottom of the transmission shaft is provided with a plurality of arc-shaped blocks, the arc-shaped blocks extend outwards from the center position of the transmission shaft to realize the assembly of the arc-shaped blocks in the arc-shaped grooves to control the expansion/contraction of the reaming speed, the top of the guide groove is provided with a limiting groove along the circumferential direction to ensure the rotation of the transmission shaft, and meanwhile, the upper part of the guide groove is provided with a positioning groove along the circumferential direction for assembling an arc-shaped key and an air passage, and the air passage is formed by communicating and processing an air inlet hole in the middle of the top of;

d. the assembly, the hole of hole digger up, the reaming piece is put into from the hole of hole digger terminal surface respectively, slides to the pilot hole, and three reaming pieces pack into the reaming piece after, make it in recovery position (figure 5), then assemble the constant head tank of central axis with the arc piece on, later insert the hole of hole digger with it in, the epaxial arc piece of central axis is as for in the arc wall of reaming piece this moment.

Based on the foregoing specific embodiment, the step d further includes: the transmission shaft is assembled in the positioning groove of the transmission shaft and is placed on one side of the guide groove, the transmission shaft is assembled in the shaft hole of the hole opener assembled with the hole expanding block through the guide groove and the guide strip, the arc block is matched with the arc groove of the hole expanding block, the transmission shaft is rotated, the position of the arc key is adjusted through the pin hole and is moved to the guide groove, and the position occupying pin is added through the pin hole and is sealed by the expansion pin.

Based on the above specific embodiment, the method further comprises a step e of disassembling the drilling tool, and when the drilling tool is in a retracted state, after the occupied pin and the expansion pin are punched out by a punching pin with a diameter smaller than that of the disassembling hole, the arc-shaped key is slid to the other side, and then the central shaft is lifted out to remove the reaming block.

To sum up, the utility model discloses a centrifugal pipe following drilling tool has solved traditional pipe following drilling tool if will change the problem that then need change this drilling tool in the use, and the design through split type structure can effectual improvement drilling tool's practicality to can change the effect that the hole digger can according to the wearing and tearing condition of hole digger, thereby the effectual maintenance cost that reduces the drilling tool also can improve the maintenance efficiency of drilling tool.

The above description is only exemplary of the present invention and should not be taken as limiting the scope of the present invention, as any modifications, equivalents, improvements and the like made within the spirit and principles of the present invention are intended to be included within the scope of the present invention.

Claims

1. A centrifugal pipe-following drilling tool is characterized in that: comprises a transmission shaft (1), a hole opener (2) and a hole expanding block (3);

the number of the reaming blocks (3) is at least 2, arc-shaped grooves (31) are formed in the reaming blocks (3), arc-shaped blocks (11) are arranged at the top of the transmission shaft (1) so that the arc-shaped blocks can be assembled on the arc-shaped grooves, the arc-shaped ends of the arc-shaped blocks are located at the center of the transmission shaft, and the reaming blocks (3) are expanded/contracted through the arc-shaped grooves (31) and the arc-shaped blocks (11);

the side surface of the hole digger is also provided with an assembling hole (21) for assembling a hole enlarging block (3), the transmission shaft can be assembled in the shaft hole of the hole digger and can slide in the assembling hole through the arc-shaped groove (31) and the arc-shaped block (11).

2. A centrifugal casing-following drill as claimed in claim 1, wherein: the lower part of transmission shaft (1) is provided with a plurality of guide ways (12) that are used for the assembly location, and the upper portion of hole digger (2) inside wall is provided with guide strip (22) that match with the guide way.

3. A centrifugal casing-following drill as claimed in claim 2, wherein: a limit groove (13) is further arranged above the guide groove (12), the width of the limit groove is larger than that of the guide groove, and the transmission shaft is assembled in the hole digger and then enables the bottom edge of the guide groove to be matched with the bottom edge of the guide strip to realize limiting through rotation.

4. A centrifugal casing-following drill as claimed in claim 2, wherein: the side edge of the guide groove is also provided with a positioning groove (14), one end of the positioning groove is communicated with the guide groove, the side edge of the top of the positioning groove is lower than the bottom edge of the limiting groove, the limiting groove is communicated with the positioning groove, and an arc-shaped key (4) is arranged in the guide groove, assembled in the positioning groove and moved to the position of the guide groove so as to realize assembly positioning.

5. A centrifugal casing-following drill as claimed in claim 4, wherein: the length of the arc key (4) along the circumferential direction is longer than the width of the guide groove so as to realize the installation effect of the arc key, and a pin hole (23) used for assembling the arc key in the positioning groove is arranged at the position corresponding to the side wall of the hole digger (2).

6. A centrifugal casing-following drill as claimed in claim 4 or 5, wherein: still including being used for avoiding the gliding occupy-place round pin (5) of arc key, occupy-place round pin passes through the pinhole and assembles in the location of realization arc key in the constant head tank to realize sealed assembly in the pinhole through expansion pin (9).

7. A centrifugal casing-following drill as claimed in claim 1, wherein: this transmission shaft bottom is provided with venthole (7), and the top of this transmission shaft still is provided with inlet port (6), and this inlet port forms the air flue with the venthole intercommunication, and the bottom of hole digger still is provided with a plurality of fumaroles (8), and is opened/closed with the control fumarole through the flexible of reaming piece to the gaseous high-pressure gas or the liquid that pass through fumarole blowout and restriction external environment of realization venthole flow backward.

8. A centrifugal casing-following drill as claimed in claim 1, wherein: the transmission shaft (1) is further provided with an assembly limiting block (15) matched with the end face of the hole digger, and the assembly limiting block is matched with the end face of the hole digger in a hard mode to realize assembly limiting and realize sealing and transmission impact.

9. A centrifugal casing-following drill as claimed in claim 1, wherein: the reaming piece is three, and three reaming pieces constitute complete plane in closed state bottom surface, and the arc piece is three to the curved other end of arc piece extends to the lateral wall of transmission shaft.