CN211201769U - A down-the-hole hammer reverse circulation follower drill bit suitable for large-diameter drilling - Google Patents

Abstract

The utility model discloses a down-the-hole hammer reverse circulation follower drill bit suitable for large-diameter drilling, which comprises an upper drill bit body and a lower drill bit body, wherein the lower drill bit body is hung on the lower part of the upper drill bit body, and the upper drill bit body and the The middle part of the lower bit body is provided with a central channel, the lower part of the upper bit body is provided with a groove, the top of the lower bit body is provided with a convex shaft, the groove is corresponding to the shape of the convex shaft, and the convex shaft is inserted in the groove, The hole diameter of the groove is larger than the outer diameter of the convex shaft, and the convex shaft can slide in the groove. When the convex shaft slides and abuts against one end of the groove, the bottom of the lower bit body moves out of the outer edge of the drilling tool to realize reaming drilling. . Beneficial effects: double slag suction channels are set at the bottom of the hole, and the involute slag discharge guide groove on the bottom of the drill bit is matched with high reverse circulation efficiency, high impact energy efficiency of the DTH hammer, and good slag discharge effect. The arrangement, combined with good slag discharge conditions, effectively increases the service life of the drill bit.

Description

A down-the-hole hammer reverse circulation follower drill bit suitable for large-diameter drilling

technical field

The utility model relates to a down-the-hole hammer reverse-circulation follow-pipe drill bit, in particular to a down-the-hole hammer reverse-circulation follow-pipe drill bit suitable for large-diameter drilling.

Background technique

At present, in the geotechnical drilling and excavation engineering, complex formations such as broken, loose, lost, and gravel are often encountered. Under such conditions, the construction of pile holes, especially large-diameter pile holes, is difficult to drill and the construction period is long. , The hole forming efficiency is low, and the accident in the hole occurs frequently. DTH hammer and tube drilling technology is a kind of drilling method that combines with air down-the-hole hammer to expand bottom drilling and synchronously follow the casing. When the pipe diameter is slightly larger, the down-the-hole hammer simultaneously hammers the casing shoe to make the casing follow up synchronously, so as to protect the wall of the drilling hole and prevent the hole from collapsing and collapsing. When the casing follows the complete formation, the bottom-reaming bit is retracted and pulled out of the casing, so as to smoothly pass through the broken and complex formation. DTH hammer and tube drilling technology is widely used in the construction of engineering pile holes due to its excellent performance, high drilling efficiency and hole quality. At present, DTH hammer and tube bit can be divided into double bit type with casing bit and reaming bit type without casing bit according to the type of bit. The dual bit type drills with the tube, which has high formation adaptability and drilling quality. Well, drilling is stable, but because the casing bit cannot be replaced, the drilling depth is limited, and once the casing bit is severely worn, it cannot be drilled. The reaming and tube drill bit can realize reaming drilling through the expansion mechanism during drilling. After drilling, the drill bit can be retracted and can be freely pulled out of the hole, but whether it is an eccentric type, a valve type or a reaming wing type The diameter-reducing mechanism of the reaming drill is that under the action of drilling pressure and friction, the drilling tool is rotated or pulled to realize the diameter change. Under complex formation conditions, it is very easy to cause rock dust and debris to be blocked, the variable diameter mechanism is stuck, or the rotation angle is large, which leads to the withdrawal of the drilling tool and the drill pipe. Once the failure of the reducing mechanism occurs, it will cause a major accident in the hole, and it will be difficult to handle, which will seriously affect the project progress and economic cost. In addition, for large-diameter DTH hammers, from the perspective of its circulation mode, the positive circulation form has problems such as incomplete slag discharge, unclean hole bottom, large air volume and high cost. Therefore, a DTH hammer reverse circulation follower drill bit for large-diameter drilling is designed, which adopts the form of a reaming bit to improve its structure, increase the reliability and safety of the reducing mechanism under complex working conditions, and improve the slag discharge effect. Bit life and drilling efficiency.

SUMMARY OF THE INVENTION

The purpose of this utility model is to solve the existing problems such as large construction difficulty, long construction period, low efficiency and frequent accidents in the construction of large-diameter engineering piles in complex strata, and provides a kind of large-diameter drilling hole. DTH hammer reverse circulation with tube bit.

The down-the-hole hammer reverse circulation follower drill bit provided by the utility model for large-diameter drilling comprises an upper bit body and a lower bit body, wherein the lower bit body is hung on the lower part of the upper bit body, and the upper bit body and the lower bit body are suspended. The middle part of the drill bit body is provided with a central channel, the lower part of the upper bit body is provided with a groove, the top of the lower bit body is provided with a convex shaft, the groove is corresponding to the shape of the convex shaft, the convex shaft is inserted in the groove, and the groove is The hole diameter is larger than the outer diameter of the protruding shaft, and the protruding shaft can slide in the groove. When the protruding shaft slides and abuts one end of the groove, the bottom of the lower bit body moves out of the outer edge of the drilling tool to realize reaming drilling.

The upper part of the upper bit body is provided with splines, and the upper bit body is connected with the pneumatic down-the-hole hammer impactor through the splines. In the groove of the splines, there are several transparent injection holes on the side wall of the upper bit body. The holes are all communicated with the central channel in the middle part of the upper bit body, the upper bit body is also covered with a casing shoe, the inner side wall of the lower part of the casing shoe is provided with an inner step, and the side wall of the upper bit body corresponding to the inner step is provided. A suspension boss is arranged on the upper part, the upper bit body and the casing shoe are clamped with the suspension boss through an inner step, a fixing pin is inserted on the side wall of the lower part of the upper bit body, and the lower bit body is suspended by the fixing pin. on the upper drill body.

The side wall of the upper bit body is also provided with a slag suction channel, the inlet of the slag suction channel is located at the bottom of the upper bit body, and the outlet of the slag suction channel is communicated with the central channel in the middle part of the upper bit body.

The lower bit body is provided with a shoulder, the bottom of the upper bit body abuts on the shoulder, the lower bit body and the upper bit body are provided with an arc-shaped groove at the corresponding position where the fixing pin is arranged, and the fixing pin on the upper bit body is inserted In the arc-shaped groove, the lower bit body can slide in the track of the arc-shaped groove, the lower part of the lower bit body is provided with a cutting surface, the bottom of the lower bit body is embedded with carbide ball teeth, and the bottom of the lower bit body is The bottom is also provided with several slag discharge guide grooves, and the outlets of the several slag discharge guide grooves are all connected with the inlet of the middle channel at the bottom of the lower bit body.

Several slag discharge guide grooves are arranged in the form of involutes around the inlet of the central channel at the bottom of the lower bit body.

The groove on the lower part of the upper drill body is an oblong groove with the arc line as the symmetrical axis, and the shape of the convex shaft on the upper part of the lower drill body corresponds to the shape of the oblong groove.

The carbide ball teeth at the bottom of the lower bit body are fully covered and cross-inlaid along the rotary cutting path. At the same time, the side edges of the bottom edge of the lower bit body are also embedded with cemented carbide ball teeth, and the rotating protrusions at the bottom of the lower bit body are densely embedded with hard alloy balls. Alloy ball teeth.

The top of the casing shoe is connected with the casing through a thread.

The working principle of the present utility model:

When the down-the-hole hammer reverse circulation follower drill bit provided by the utility model is suitable for large-diameter drilling, the rotary action generated by the drilling rig drives the upper bit body to rotate through the spline, and drives the lower bit body to rotate synchronously, while compressing the air The pneumatic down-the-hole hammer is driven to move, and the impact action is transmitted to the lower bit body through the upper bit body. Under the combined action of impact and rotation, the carbide ball teeth start to grind the rock for drilling. Under the action of cutting resistance and friction, the convex shaft on the upper part of the lower bit body rotates along the arc-shaped groove track in the groove on the lower part of the upper bit body, and gradually rotates out of the outer edge of the drilling tool. Constrained by the size of the convex shaft and the groove, After the convex shaft rotates a small angle, it fits with one end of the groove and reaches the displacement limit. At this time, the maximum turning diameter is larger than the diameter of the casing, and the reaming drilling is realized. The size of the reaming hole can be controlled by changing the size of the boss and groove. The reaming bit drives the casing to move down together through the casing shoe. When the drill bit is fully opened, the central channel of the upper bit body and the central channel of the lower bit body are coaxially connected, the slag suction channel on the side wall of the upper bit body is opened, and the compressed gas generates high-speed and high-pressure jet through the jetting hole and forms a jet suction effect, which is driven by the high-speed jet. At the same time, the gas in the gap between the hole wall carries the rock powder and cuttings into the central channel along the slag suction channel and the bottom surface slag discharge guide channel, and discharges the rock powder and cuttings to the surface, forming a reverse circulation. After drilling, lift the drilling tool lightly to remove the drilling pressure, the drilling rig reversely rotates a small angle, the convex shaft rotates in the reverse direction along the arc groove trajectory, the lower bit body is retracted to the initial closed state, and the lower bit body and the drilling tool are coaxial. , the drill bit can be directly extracted from the casing at this time. If the lower bit body is blocked from retracting, the drill can be slowly rotated and lifted. Under the action of the cutting surface of the outer edge of the lower bit body, the lower bit body can be forced to slide into the casing, and then the drilling tool can be lifted out of the hole.

The fixed pin on the upper bit body only plays the role of suspension. When drilling, the impact effect of the DTH hammer is directly transmitted to the shoulder of the lower bit body through the bottom surface of the upper bit body, and then acts on the carbide ball teeth, impacting and cutting the rock. . The cemented carbide ball tooth arrangement adopts the principle that the outer edge of the bottom edge of the lower bit body is densified, the inside is evenly distributed, and the bottom surface of the bit is fully covered and crossed along the rotary cutting path.

The beneficial effects of the present utility model:

The down-the-hole hammer reverse circulation and tube drill bit suitable for large-diameter drilling provided by the utility model adopts a curved groove structure shaft to cooperate to form a diameter-reducing mechanism of the reaming drill bit, and the diameter-reducing effect can be achieved only by forwardly rotating a small angle. . After stopping drilling, the reaming bit can be retracted by reversing a small angle. This configuration reduces the chance of the drill bit getting stuck when retracting. In addition, a cutting surface is arranged on the lower bit body rotating out of the outer edge. When the recovery fails, the lower bit body can be forcibly restrained from sliding into the casing, and the drilling tool can be lifted out of the hole. At the same time, the bottom surface of the drill bit is a whole, with high structural strength, which can better meet the requirements of the impact effect of large-diameter drill bits. The impact action of the down-the-hole hammer is directly transmitted to the top surface of the lower bit body through the bottom surface of the upper bit body, and then acts on the hard alloy ball teeth, impacting and cutting the rock, and the energy transfer efficiency is high. In addition, the current large-diameter DTH hammer mostly adopts the positive circulation mode, which has the problems of large gas volume required, poor slag discharge effect, and high energy consumption. With the involute slag discharge guide groove on the bottom surface of the drill bit, the reverse circulation efficiency is high, the impact energy efficiency of the DTH hammer is high, and the slag discharge effect is good. the life of the drill bit.

Description of drawings

FIG. 1 is a schematic diagram of the overall structure of the reverse circulation follower drill bit according to the present invention.

FIG. 2 is a schematic cross-sectional structural diagram of the reverse circulation follower drill bit according to the present invention.

3 is a front view of the combined structure of the upper drill bit body and the lower drill bit body according to the present invention.

FIG. 4 is a schematic structural diagram of the upper drill bit body according to the present invention.

FIG. 5 is a schematic structural diagram of the lower drill bit body according to the present invention.

FIG. 6 is a schematic diagram of the working state of the reverse circulation follower drill bit according to the present invention.

The annotations in the figure above are as follows:

1. Upper drill body 2. Lower drill body 3. Center channel 4. Groove 5. Convex shaft

6. Spline 7. Injection hole 8. Casing shoe 9. Inner step 10. Suspension boss

11. Slag suction channel 12. Fixed pin 13. Shoulder 14. Arc groove 15. Cutting surface

16. Carbide ball teeth 17. Slag discharge guide groove.

Detailed ways

Please refer to Figures 1 to 6 as shown:

The down-the-hole hammer reverse circulation follower drill bit provided by the utility model for large-diameter drilling includes an upper drill bit body 1 and a lower drill bit body 2, wherein the lower drill bit body 2 is hung on the lower part of the upper drill bit body 1, and the upper drill bit body 1 and the middle part of the lower bit body 2 are provided with a central channel 3, the lower part of the upper bit body 1 is provided with a groove 4, the top of the lower bit body 2 is provided with a convex shaft 5, and the shape of the groove 4 is corresponding to the convex shaft 5 , the convex shaft 5 is inserted in the groove 4, the hole diameter of the groove 4 is larger than the outer diameter of the convex shaft 5, the convex shaft 5 can slide in the groove 4, when the convex shaft 5 slides and abuts against the groove 4 At one end, the bottom of the lower bit body 2 moves out of the outer edge of the drilling tool to realize reaming drilling.

The upper part of the upper bit body 1 is provided with a spline 6, and the upper bit body 1 is connected with the pneumatic down-the-hole hammer impactor through the spline 6. In the groove of the spline 6, there are several transparent holes on the side wall of the upper bit body 1. The injection holes 7, several injection holes 7 are all communicated with the central channel 3 in the middle part of the upper bit body 1, the upper bit body 1 is also covered with a casing shoe 8, and the inner side wall of the lower part of the casing shoe 8 is provided with an inner wall. Step 9, a suspension boss 10 is provided on the side wall of the upper bit body 1 at the position corresponding to the inner step 9, and the upper bit body 1 and the casing shoe 8 are clamped with the suspension boss 10 through the inner step 9, and the upper bit A fixing pin 12 is inserted into the side wall of the lower part of the body 1 , and the lower bit body 2 is hung on the upper bit body 1 through the fixing pin 12 .

The side wall of the upper bit body 1 is also provided with a slag suction channel 11 , the inlet of the slag suction channel 11 is located at the bottom of the upper bit body 1 , and the outlet of the slag suction channel 11 communicates with the central channel 3 in the middle of the upper bit body 1 .

The lower bit body 2 is provided with a shoulder 13, the bottom of the upper bit body 1 abuts on the shoulder 13, the lower bit body 2 and the upper bit body 1 are provided with an arc groove 14 at the corresponding position of the fixing pin 12, and the upper bit body 1 is provided with an arc groove 14. The fixing pin 12 on the drill body 1 is inserted into the arc groove 14, the lower drill body 2 can slide in the track of the arc groove 14, the lower part of the lower drill body 2 is provided with a cutting surface 15, and the lower drill body 2 is provided with a cutting surface 15. The bottom of 2 is embedded with cemented carbide ball teeth 16, and the bottom of the lower bit body 2 is also provided with several slag discharge guide grooves 17. The import is connected.

Several slag discharge guide grooves 17 are arranged in the form of involutes around the inlet of the central channel 3 at the bottom of the lower bit body 2 .

The groove 4 in the lower part of the upper drill body 1 is an oval groove with the arc line as the symmetry axis, and the shape of the convex shaft 5 on the upper part of the lower drill body 2 corresponds to the shape of the oval groove.

The carbide ball teeth 16 at the bottom of the lower bit body 2 are fully covered and cross-inlaid along the rotary cutting path. At the same time, the side edges of the bottom edge of the lower bit body 2 are also embedded with cemented carbide ball teeth, and the protruding part is rotated at the bottom of the lower bit body 2. Cemented carbide ball teeth 16 are encrypted and embedded.

The top end of the casing shoe 8 is connected with the casing through a thread.

The working principle of the present utility model:

When the down-the-hole hammer reverse circulation follower drill bit provided by the utility model is suitable for large-diameter drilling, the rotary action generated by the drilling rig drives the upper bit body 1 to rotate through the splines 6, and drives the lower bit body 2 to rotate synchronously. At the same time, the compressed air drives the pneumatic down-the-hole hammer to move, and the impact action is transmitted to the lower bit body 2 through the upper bit body 1. Under the combined action of impact and rotation, the carbide ball teeth 16 start to grind the rock for drilling. Under the action of cutting resistance and friction, the convex shaft 5 on the upper part of the lower bit body 2 rotates along the trajectory of the arc-shaped groove 14 in the groove 4 at the lower part of the upper bit body 1, and gradually rotates out of the outer edge of the drilling tool, and is affected by the convex shaft 5. Constrained by the size of the groove 4, the convex shaft 5 rotates a small angle and then fits with one end of the groove 4 to reach the displacement limit. At this time, the maximum turning diameter is larger than the casing diameter to realize reaming drilling. The size of the reaming hole can be controlled by changing the size of the protruding shaft 5 and the groove 4 . The reaming bit drives the casing to move downward together through the casing shoe 8 . When the drill bit is fully opened, the central channel 3 in the middle part of the upper bit body 1 and the central channel 3 in the middle part of the lower bit body 2 are coaxially connected, the slag suction channel 11 on the side wall of the upper bit body 1 is opened, and the compressed gas passes through the injection hole 7 A high-speed and high-pressure jet is generated and a jet-suction effect is formed. Driven by the high-speed jet, the rock powder and cuttings are carried by the gas in the gap of the hole wall and enter the central channel 3 along the slag suction channel 11 and the bottom surface slag discharge guide groove 17, and the rock powder and cuttings are discharged into the center channel 3. surface, forming a reverse cycle. After the drilling is completed, lightly lift the drilling tool to remove the drilling pressure, the drilling rig reversely rotates a small angle, the convex shaft 5 rotates in the reverse direction along the trajectory of the arc groove 14, the lower bit body 2 is retracted to the initial closed state, and the lower bit body 2 and the drill With a coaxial line, the drill bit can be directly extracted from the casing at this time. If the lower bit body 2 is blocked from retracting, the drill can be slowly rotated and lifted. Under the action of the cutting surface 15 of the outer edge of the lower bit body 2, the lower bit body 2 can be forcibly restrained from sliding into the casing, and then the drilling tool can be lifted out of the hole.

The fixed pin 12 on the upper drill body 1 only plays a role of suspension. When drilling, the impact of the DTH hammer is directly transmitted to the shoulder 13 of the lower drill body 2 through the bottom surface of the upper drill body 1, and then acts on the carbide ball teeth 16. , impact cutting to break the rock. The arrangement of the cemented carbide ball teeth 16 adopts the principle that the outer edge of the bottom edge of the lower bit body 2 is densified, and the interior is evenly distributed, and the bottom surface of the lower bit body 2 is fully covered and crossed along the rotary cutting path.

Claims (7)

1. The utility model provides a down-the-hole hammer reverse circulation is with pipe drill bit suitable for major diameter drilling which characterized in that: the drilling tool comprises an upper drill bit body and a lower drill bit body, wherein the lower drill bit body is hung on the lower portion of the upper drill bit body, a central channel is formed in the middle of the upper drill bit body and the middle of the lower drill bit body, a groove is formed in the lower portion of the upper drill bit body, a protruding shaft is arranged at the top end of the lower drill bit body, the groove corresponds to the protruding shaft in shape, the protruding shaft is inserted into the groove, the aperture of the groove is larger than the outer diameter of the protruding shaft, the protruding shaft can slide in the groove, and when the protruding shaft slides and abuts against one end of the groove, the bottom of the lower drill bit body.

2. A down-the-hole hammer reverse circulation casing bit suitable for large diameter drilling according to claim 1, wherein: the upper portion of going up the drill bit body be provided with the spline, it is connected with pneumatic down-the-hole hammer impacter through the spline to go up the drill bit body, set up several penetrating injection pore on the lateral wall of the drill bit body on the inslot of spline, several injection pore all are linked together with the central channel of last drill bit body middle part, it still covers and is equipped with the casing shoe on the drill bit body to go up, be provided with interior step on the inside wall of casing shoe lower part, be provided with on the last drill bit body lateral wall of the position that corresponds with interior step and hang the boss, go up between drill bit body and the casing shoe through interior step and hang the boss looks joint, it is equipped with the fixed pin to insert on the lateral wall of upper.

3. A down-the-hole hammer reverse circulation casing bit suitable for large diameter drilling according to claim 1, wherein: the side wall of the upper drill bit body is also provided with a slag suction channel, the inlet of the slag suction channel is positioned at the bottom of the upper drill bit body, and the outlet of the slag suction channel is communicated with the central channel in the middle of the upper drill bit body.

4. A down-the-hole hammer reverse circulation casing bit suitable for large diameter drilling according to claim 1 or 2, wherein: the lower drill bit body on be provided with the circular bead, the bottom of going up the drill bit body supports and leans on the circular bead, lower drill bit body and last drill bit body set up the corresponding position department of fixed pin and are provided with the arc wall, the fixed pin on the last drill bit body is inserted and is established in the arc wall, lower drill bit body can slide in the orbit of arc wall, one side of lower drill bit body lower part is provided with the cutting surface, the bottom of lower drill bit body inlays and is equipped with carbide button, the bottom of lower drill bit body still is provided with several sediment guide slots, the export of several sediment guide slots all is linked together with the centre channel import of lower drill bit body bottom.

5. A down-the-hole hammer reverse circulation casing bit suitable for large diameter drilling according to claim 4, wherein: the plurality of slag discharge guide grooves are arranged around the inlet of the central channel at the bottom of the lower drill bit body in an involute form.

6. A down-the-hole hammer reverse circulation casing bit suitable for large diameter drilling according to claim 1, wherein: the groove at the lower part of the upper drill bit body is a long circular groove taking an arc line as a symmetrical axis, and the shape of the convex shaft at the upper part of the lower drill bit body corresponds to that of the long circular groove.

7. A down-the-hole hammer reverse circulation casing bit suitable for large diameter drilling according to claim 4, wherein: the hard alloy spherical teeth at the bottom of the lower drill bit body are embedded in a full-covering and crossed mode along a rotary cutting path, meanwhile, the hard alloy spherical teeth are embedded in the side edge of the bottom edge of the lower drill bit body, and the hard alloy spherical teeth are embedded in the rotary extending part at the bottom of the lower drill bit body in a dense mode.

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