Combined large-aperture down-the-hole drill bit

Abstract

A combined large-aperture down-the-hole drill bit comprises a drill bit body, a movable sub hammer and a locking system, wherein a transmission spline is arranged at the tail end of the drill bit body; an inner ring mounting position group and an outer ring mounting position group are sequentially arranged on the drilling surface of the drill bit body from the center to the outside, the inner ring mounting position group comprises a plurality of mounting positions which are uniformly distributed around the central axis of the drill bit body to form inner ring mounting positions, and the outer ring mounting position group comprises a plurality of mounting positions which are uniformly distributed around the central axis of the drill bit body to form outer ring mounting positions; according to the utility model, the movable sub-hammers can be replaced only by disassembling the locking system, so that the replacement time and the manpower consumption are reduced, and the utilization rate of the drill bit body can be improved at the same time.

Description

Technical Field

[0001] The utility model relates to a combined large-aperture down-the-hole bit. Background Art

[0002] With the development of down-the-hole drilling technology, while applying the large-aperture down-the-hole drilling technology to the pile foundation field, deficiencies of the existing down-the-hole bits have also been found:

[0003] 1. When the bit reaches the scrapping standard, the bit body and the transmission spline of the bit are often not severely worn, resulting in the discard of the bit body and the transmission spline that could still be utilized, and the utilization rate of the bit is not high;

[0004] 2. When the alloy teeth of the bit are severely worn and reach the scrapping standard, it is necessary to remove the front joint of the drill tool for replacement. Since the outer diameter of the down-the-hole hammer is large and heavy, it takes longer time and more labor to replace the bit;

[0005] 3. Most of the geological conditions where large-aperture down-the-hole bits are used are backfill layers. The instability of the rock formation easily causes the fracture of the bit alloy, resulting in the premature failure of the bit;

[0006] 4. With the engineering requirements, the construction aperture is getting larger and larger, and the difficulty and cost of bit replacement also increase accordingly. Content of the Utility Model

[0007] The utility model solves the deficiencies of the existing technology and provides a combined large-aperture down-the-hole bit that facilitates the replacement of the movable sub-hammer and improves the service life of the bit.

[0008] To achieve the above object, the utility model first proposes a combined large-aperture down-the-hole bit, which includes a bit body with a transmission spline at the tail end, a movable sub-hammer, and a locking system; on the drilling surface of the bit body, an inner ring installation position group and an outer ring installation position group are sequentially arranged from the center to the outside. The inner ring installation position group includes multiple installation positions evenly arranged around the central axis of the bit body to form an inner ring installation position, and the outer ring installation position group includes multiple installation positions evenly arranged around the central axis of the bit body to form an outer ring installation position. A movable sub-hammer is installed in each installation position through a connecting piece, and the movable sub-hammer realizes axial limit and rotational assembly with the connecting piece through the locking system.

[0009] In this embodiment, the total drilling area covered by the movable sub-hammers installed in the movable inner ring installation positions and the movable sub-hammers installed in the outer ring installation positions during rotation covers the entire drilling surface.

[0010] In this embodiment, an opening is provided on the outer circle of the bit body and communicates with the outer ring installation position, and the outer circle of the movable sub-hammer installed in the outer ring installation position protrudes from the outer circle of the bit body through the opening.

[0011] In this embodiment, a plurality of first slag discharge grooves arranged axially are provided on the outer circumference of the drill bit body. The plurality of first slag discharge grooves are evenly arranged around the central axis of the drill bit body, and the first slag discharge grooves are arranged between adjacent outer ring installation positions. On the first slag discharge groove, a chamfer is provided on the side wall on the windward side during drilling to form a helical surface, and alloy teeth are fixed on the helical surface.

[0012] In this embodiment, first air grooves arranged radially and matching the number of the first slag discharge grooves on the outer circumference are provided on the drilling surface of the drill bit body. One end of the first air groove is communicated with the first slag discharge groove, and the other end of the first air groove is communicated with the main air hole or the inner ring installation position. The main air hole and the inner ring installation position are arranged at intervals.

[0013] As an embodiment of the connecting member, the connecting member includes a flange shaft. The flange shaft includes a positioning shaft, a mounting shaft and a flange plate which are coaxially connected. The positioning shaft and the mounting shaft are respectively fixed on both sides of the flange plate. A first mounting inner hole matching the size of the mounting shaft is coaxially arranged on the bottom surface of the movable sub-hammer. A second mounting inner hole matching the positioning shaft is provided in the mounting position of the drill bit body. A flange mounting platform matching the flange plate is formed on the outer circumference at the top of the second mounting inner hole in the mounting position. A screw hole matching the counterbore on the flange plate is provided on the flange mounting platform. The flange plate is fixed in the flange mounting platform of the drill bit body through bolts to realize the connection between the flange shaft and the drill bit body. The mounting shaft is inserted into the first mounting inner hole of the movable sub-hammer, and the inner wall of the mounting shaft and the first mounting inner hole are rotationally assembled. The movable sub-hammer is axially limited on the mounting shaft through a locking system.

[0014] In this embodiment, a mounting position air hole is arranged at the center of the bottom of the second mounting inner hole. The mounting position air hole is communicated with the air passage hole in the drill bit body. An axial center air hole communicated with the mounting position air hole is provided in the center of the flange shaft. A secondary air hole communicated with the axial center air hole is provided in the center of the movable sub-hammer.

[0015] In this embodiment, the locking system includes a cross pin, a buffer pin and a hole retaining ring. A locking annular groove matching the size of the cross pin is provided on the outer circumference of the mounting shaft. A pin hole matching the locking annular groove is provided on the side surface of the movable sub-hammer. The pin hole is communicated with the mounting inner hole. After the movable sub-hammer is sleeved on the mounting shaft, the pin hole is communicated with the locking annular groove. The cross pin is inserted into the pin hole and placed in the locking annular groove. The buffer pin and the hole retaining ring are inserted into the pin hole to limit the cross pin in the pin hole.

[0016] In this embodiment, second slag discharge grooves symmetrically arranged around the central axis of the movable sub-hammer are provided on the outer circumference of the movable sub-hammer. Second air grooves arranged radially and matching the number of the second slag discharge grooves are provided on the tooth surface of the movable sub-hammer. One end of the second air groove is communicated with the second slag discharge groove, and the other end is communicated with the secondary air hole at the center of the movable sub-hammer.

[0017] As another embodiment of the connecting member, the connecting member includes a mounting shaft fixed in the mounting position, and the mounting shaft and the drill bit body are integrally formed; a first mounting inner hole matching the size of the mounting shaft is coaxially arranged on the bottom surface of the movable sub-hammer, the mounting shaft is inserted into the first mounting inner hole of the movable sub-hammer, the mounting shaft and the inner wall of the first mounting inner hole are rotationally assembled, the movable sub-hammer is axially limited on the mounting shaft through a locking system, and the mounting position air hole in the drill bit body penetrates through the mounting shaft and communicates with the auxiliary air hole on the movable sub-hammer.

[0018] Due to the above structure, the drill bit body rotates around the rotation center as the axis, and each movable sub-hammer rotates around its own axis, forming a rock drilling method of a planetary gear train, which can effectively solve the fracture of the drill bit alloy caused by the instability of the rock formation, resulting in the premature failure of the drill bit; at the same time, the scattered air holes can ensure that the rock debris is effectively discharged through each channel as soon as possible, reducing the repeated grinding of the rock debris on the drill bit and the alloy teeth, thereby improving the service life of the drill bit; when the movable sub-hammer reaches the scrapping standard, there is no need to disassemble the front joint of the impactor like the existing drill bit for replacement, and only the locking system needs to be disassembled to replace the movable sub-hammer, thereby reducing the replacement time and labor consumption, and also improving the utilization rate of the drill bit body. Brief Description of the Drawings

[0019] Figure 1 It is a schematic structural diagram of Embodiment 1 of the present invention;

[0020] Figure 2 It is a schematic structural diagram of the drilling surface of Embodiment 1 of the present invention;

[0021] Figure 3 It is a schematic structural diagram of the outer ring mounting position of Embodiment 1 of the present invention;

[0022] Figure 4 It is a sectional view of Embodiment 1 of the present invention.

[0023] Figure 5 For Figure 4 The structural schematic diagram of the connection between the middle flange shaft and the drill bit body.

[0024] Figure 6 It is a schematic structural diagram of the locking system of the present invention.

[0025] Figure 7 It is a schematic structural diagram of Embodiment 2 of the present invention.

[0026] Figure 8 It is a schematic structural diagram of the outer ring mounting position of Embodiment 2 of the present invention.

[0027] Figure 9 It is a sectional view of Embodiment 2 of the present invention.

[0028] In the figure: 1. Drill bit body; 11. Air passage hole; 111. Machining hole; 112. Plug; 12. Main water hole; 13. Installation position air hole; 14. Installation position; 15. Flange installation platform; 16. Second installation inner hole; 17. First slag discharge groove; 171. Helical surface; 172. Alloy tooth; 18. First air groove; 19. Main air hole 19; 2. Movable sub-hammer; 21. Auxiliary air hole; 22. Second air groove; 23. Second slag discharge groove; 24. First installation inner hole; 25. Pin hole; 3. Locking system; 31. Transverse pin; 32. Buffer pin; 33. Hole retaining ring; 4. Bolt; 5. Flange shaft; 51. Positioning shaft; 52. Installation shaft; 53. Flange plate. Detailed implementation manners

[0029] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0030] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0031] Embodiment 1:

[0032] As Figures 1 to 5 shown, a combined large-aperture down-the-hole drill bit includes a drill bit body 1 with a transmission spline at the tail end, a movable sub-hammer 2, and a locking system 3.

[0033] A main water hole 12 is provided in the drill bit body 1 along the central axis direction. The drill bit body 1 is machined with air passage holes 11 arranged radially and communicated with the main water hole 12 at the drilling end. When the air passage holes 11 are machined, machining holes 111 are formed on the outer circle of the drill bit body 1. The machining holes 111 are sealed by plugs 112 or sealed by metal plugs and welding (so that the air passage holes 11 are blind holes to prevent air flow from flowing outwards from the machining holes 111). On the drilling surface of the drill bit body 1, an inner ring installation position group and an outer ring installation position group matching the movable sub-hammer 2 are arranged from the center outwards. Both the inner ring installation position group and the outer ring installation position group include a plurality of installation positions evenly arranged around the central axis of the drill bit body 1 to form an inner ring installation position and an outer ring installation position respectively. The movable sub-hammer 2 is installed in the installation positions through connectors, and the movable sub-hammer 2 is axially limited on the connectors by a locking system 3. While preventing the movable sub-hammer 2 from detaching from the connectors, the locking system 3 enables the movable sub-hammer 2 to rotate around its own central axis on the connectors (in this way, when working in unstable rock formations, the rotation of the movable sub-hammer 2 can prevent the alloy teeth on the movable sub-hammer 2 from breaking due to the sudden increase in resistance and resulting in premature failure). When the drill bit body 1 rotates, the rotation drilling area of the movable sub-hammer 2 covers the entire drilling surface, ensuring that the drill bit can better complete the rock drilling work; further, an opening is provided on the outer circle of the drill bit body and communicated with the outer ring installation position. The side surface of the movable sub-hammer 2 installed in the outer ring installation position protrudes from the outer circle of the drill bit body through the opening, thereby facilitating the discharge of rock debris.

[0034] A plurality of first slag discharge grooves 17 communicated with the drilling surface are provided on the outer circle of the drill bit body 1. The plurality of first slag discharge grooves 17 are evenly arranged around the central axis of the drill bit body 1, and the first slag discharge grooves 17 are arranged between adjacent outer ring installation positions. On the first slag discharge grooves 17, chamfers are provided on the side walls on the windward side during drilling to form helical surfaces 172. Alloy teeth 173 are fixed on the helical surfaces 172. The helical surfaces 172 and the alloy teeth 173 thereon can protect the drill bit body and increase its wear resistance. The alloy teeth 173 are used to realize the side hole cleaning and hole diameter maintaining functions.

[0035] On the drilling surface of the drill bit body 1, first air grooves arranged radially and matching the number of the first slag discharge grooves on the outer circle are provided. One end of the first air grooves is communicated with the first slag discharge grooves, and the other end of the first air grooves is communicated with the main air holes 19 or the inner ring installation positions. The main air holes 19 and the inner ring installation positions are arranged at intervals. The main air holes 19 are communicated with the main water hole 12. The main air holes 19 cooperate with the first air grooves and the first slag discharge grooves to prevent the air holes from being blocked and facilitate the discharge of rock debris.

[0036] In this embodiment, the connecting member includes a flange shaft 5. The flange shaft 5 includes a positioning shaft 51, a mounting shaft 52, and a flange plate 53 that are coaxially connected. The positioning shaft 51 and the mounting shaft 52 are respectively fixed on both sides of the flange plate 53. A first mounting inner hole matching the size of the mounting shaft 52 is coaxially provided on the bottom surface of the movable sub-hammer 2. A second mounting inner hole matching the positioning shaft 51 is provided in the mounting position of the drill bit body 1. A flange mounting platform 15 matching the flange plate 53 is formed on the outer periphery at the top of the second mounting inner hole in the mounting position. A screw hole matching the counterbore on the flange plate 53 is provided on the flange mounting platform 15. The positioning shaft 51 is inserted into the inner hole. After being inserted in place, the flange plate 53 is fixed on the flange mounting platform of the drill bit body 1 through bolts 4, thereby realizing the connection between the flange shaft 5 and the drill bit body 1. The mounting shaft 52 is inserted into the mounting inner hole of the movable sub-hammer 2. The mounting shaft 52 and the inner wall of the mounting inner hole are rotationally assembled. The movable sub-hammer 2 is axially limited on the mounting shaft 52 through a locking system 3. After the flange shaft 5 is installed, the flange plate 53 protrudes axially from the flange mounting platform 15. When the movable sub-hammer 2 is installed on the mounting shaft 52, the movable sub-hammer 2 always contacts the flange plate 53 during operation, so that the impact force is borne by the flange plate 53. When the flange plate 53 is deformed, it can be solved by replacing the flange shaft 5, with low cost and improved service life of the drill bit body 1.

[0037] A mounting position air hole 13 is provided at the center of the bottom of the second mounting inner hole 16. The mounting position air hole 13 is communicated with the air passage hole 11 in the drill bit body 1. An axial center air hole is provided in the center of the flange shaft 5 and is communicated with the mounting position air hole. A secondary air hole is provided in the center of the movable sub-hammer 2 and is communicated with the axial center air hole.

[0038] The locking system 3 includes a cross pin 31, a buffer pin 32, and a hole retaining ring 33. A locking annular groove matching the size of the cross pin 31 is provided on the outer circumference of the mounting shaft 52. A pin hole matching the locking annular groove is provided on the side surface of the movable sub-hammer 2. The pin hole 25 is communicated with the mounting inner hole. After the movable sub-hammer 2 is sleeved on the mounting shaft 52, the pin hole 25 is communicated with the locking annular groove. The cross pin 31 is inserted into the pin hole 25 and placed in the locking annular groove. The buffer pin 32 and the hole retaining ring 33 are inserted into the pin hole to limit the cross pin 31 in the pin hole, thereby realizing the axial limit of the movable sub-hammer 2 on the mounting shaft 52.

[0039] In this structure, the flange shaft 5 is a detachable part. The flange shaft 5 can be made of materials and carburizing and quenching processes superior to those of the drill bit body and the movable sub-hammer, increasing the strength and wear resistance of the flange shaft. After wear, it can be replaced according to the wear situation, improving the overall service life of the drill bit body 1.

[0040] Embodiment 2:

[0041] As Figures 7 to 9As shown in the figure, the difference between this embodiment and Embodiment 1 is that the mounting shaft 52 and the drill bit body 1 are integrally formed; the connecting member includes the mounting shaft 52 fixed in the mounting position, and the movable sub-hammer 2 is still installed on the mounting shaft 52 through the locking system 3. The air holes in the mounting position in the drill bit body 1 directly penetrate through the mounting shaft 52 and communicate with the secondary air holes on the movable sub-hammer 2;

[0042] In the above two embodiments, the outer circle of the movable sub-hammer 2 is provided with a second slag discharge groove symmetrically arranged with the central axis of the movable sub-hammer as the center. The tooth surface of the movable sub-hammer 2 is radially provided with a second air groove matching the number of the first slag discharge grooves. One end of the second air groove communicates with the second slag discharge groove, and the other end communicates with the secondary air hole 21 at the center of the movable sub-hammer 2. The secondary air hole 21 on the movable sub-hammer 2 cooperates with the second air groove 22 and the second slag discharge groove 23 to form an exhaust passage, which helps to discharge the rock slag.

[0043] During use, the drill bit body 1 rotates around the rotation center as the axis, and each movable sub-hammer 2 rotates around its own axis, forming a rock drilling method of a planetary gear system, which can effectively solve the fracture of the drill bit alloy caused by the instability of the rock formation and cause the premature failure of the drill bit; at the same time, the main and secondary air holes arranged dispersedly can ensure that the rock slag is discharged effectively and quickly through each channel, reducing the repeated grinding of the rock slag on the drill bit and the alloy teeth, thereby improving the service life of the drill bit; when the movable sub-hammer 2 reaches the scrapping standard, there is no need to disassemble the front joint of the impactor for replacement like the existing drill bit. Only by disassembling the locking system can the movable sub-hammer be replaced, thereby reducing the replacement time and labor consumption, and at the same time improving the utilization rate of the drill bit body.

[0044] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural transformation made under the concept of the present invention by using the content of the specification and drawings of the present invention, or directly / indirectly applied in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A combined large-aperture down-the-hole drill bit, characterized in that: It includes a drill bit body (1) with a driving spline at the tail end, a movable sub-hammer (2) and a locking system (3); on the drilling surface of the drill bit body (1), an inner ring installation position group and an outer ring installation position group are sequentially arranged from the center outwards. The inner ring installation position group includes a plurality of installation positions (14) evenly arranged around the central axis of the drill bit body (1) to form an inner ring installation position, and the outer ring installation position group includes a plurality of installation positions (14) evenly arranged around the central axis of the drill bit body (1) to form an outer ring installation position. A movable sub-hammer (2) is installed in each installation position (14) through a connecting piece, and the movable sub-hammer (2) realizes axial limit and rotational assembly with the connecting piece through the locking system (3).

2. The combined large-aperture down-the-hole bit according to claim 1, wherein: The total drilling area covered by the movable sub-hammers (2) installed in the inner ring installation positions during rotation is the entire drilling surface, which is the same as that of the movable sub-hammers (2) installed in the outer ring installation positions.

3. The combined large-aperture down-the-hole drill bit according to claim 1, wherein: An opening is provided on the outer circumference of the drill bit body (1) and is communicated with the outer ring installation position. The outer circumference of the movable sub-hammer (2) installed in the outer ring installation position protrudes from the outer circumference of the drill bit body (1) through the opening.

4. The combined large-aperture down-the-hole bit according to claim 1, wherein: A plurality of first slag discharge grooves (17) are arranged on the outer circumference of the drill bit body (1) along the axial direction. The plurality of first slag discharge grooves (17) are evenly arranged around the central axis of the drill bit body (1), and the first slag discharge grooves (17) are arranged between adjacent outer ring installation positions. On the first slag discharge grooves (17), a chamfer is provided on the side wall on the windward side during drilling to form a helical surface (172), and alloy teeth (173) are fixed on the helical surface (172).

5. The combined large-aperture down-the-hole drill bit according to claim 4, characterized in that: On the drilling surface of the drill bit body (1), first air grooves (18) are arranged along the radial direction and are matched with the number of the first slag discharge grooves (17) on the outer circumference. One end of the first air groove (18) is communicated with the first slag discharge groove (17), and the other end of the first air groove (18) is communicated with the main air hole (19) or with the inner ring installation position. The main air hole (19) and the inner ring installation position are arranged at intervals.

6. A combined large-aperture down-the-hole drill bit according to any one of claims 1 to 5, characterized in that: The connecting piece includes a flange shaft (5). The flange shaft (5) includes a positioning shaft (51), an installation shaft (52) and a flange plate (53) which are coaxially connected. The positioning shaft (51) and the installation shaft (52) are respectively fixed on both sides of the flange plate (53). A first installation inner hole (24) which is matched with the size of the installation shaft (52) is coaxially arranged on the bottom surface of the movable sub-hammer (2). A second installation inner hole (16) which is matched with the positioning shaft (51) is provided in the installation position (14) of the drill bit body (1). A flange installation platform (15) which is matched with the flange plate (53) is formed on the outer circumference at the top of the second installation inner hole (16) in the installation position (14). After the positioning shaft (51) is installed in the second installation inner hole (16), the flange plate (53) is detachably installed on the flange installation platform (15); the installation shaft (52) is inserted into the first installation inner hole (24) of the movable sub-hammer (2), and the inner wall of the installation shaft (52) and the first installation inner hole (24) are rotationally assembled, and the movable sub-hammer (2) is axially limited on the installation shaft (52) through the locking system (3).

7. The combined large-aperture down-the-hole drill bit according to claim 6, wherein: At the center of the bottom of the second installation inner hole (16), there is an installation position air hole (13), which is communicated with the air passage hole (11) in the drill bit body (1). The center of the flange shaft (5) is provided with an axial center air hole communicated with the installation position air hole (13), and the center of the movable sub-hammer (2) is provided with a secondary air hole (21) communicated with the axial center air hole.

8. The combined large-aperture down-the-hole bit according to claim 7, wherein: The locking system (3) includes a cross pin (31), a buffer pin (32) and a hole retaining ring (33). A locking annular groove matching the size of the cross pin (31) is arranged on the outer circumference of the installation shaft (52). A pin hole (25) matching the locking annular groove is arranged on the side surface of the movable sub-hammer (2). The pin hole (25) is communicated with the installation inner hole. After the movable sub-hammer (2) is sleeved on the installation shaft (52), the pin hole (25) is communicated with the locking annular groove. The cross pin (31) is inserted into the pin hole (25) and placed in the locking annular groove. The buffer pin (32) and the hole retaining ring (33) are inserted into the pin hole (25) to limit the cross pin (31) in the pin hole (25).

9. The combined large-aperture down-the-hole drill bit according to claim 8, characterized in that: On the outer circle of the movable sub-hammer (2), there is a second slag discharge groove (23) symmetrically arranged with the central axis of the movable sub-hammer (2) as the center. On the tooth surface of the movable sub-hammer (2), second air grooves (22) matching the number of the second slag discharge grooves (23) are arranged radially. One end of the second air groove (22) is communicated with the second slag discharge groove (23), and the other end is communicated with the secondary air hole (21) at the center of the movable sub-hammer (2).

10. A combined large-aperture down-the-hole drill bit according to any one of claims 1 to 5, characterized in that: The connecting piece includes an installation shaft (52) fixed in the installation position (14). The installation shaft (52) and the drill bit body (1) are integrally formed. The bottom surface of the movable sub-hammer (2) is coaxially provided with a first installation inner hole (24) matching the size of the installation shaft (52). The installation shaft (52) is inserted into the first installation inner hole (24) of the movable sub-hammer (2). The inner wall of the installation shaft (52) and the first installation inner hole (24) are rotationally assembled. The movable sub-hammer (2) is axially limited on the installation shaft (52) through the locking system (3). The installation position air hole (13) in the drill bit body (1) penetrates through the installation shaft (52) and is communicated with the secondary air hole (21) on the movable sub-hammer (2).

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