CN117449754A - Axial impactor - Google Patents

Abstract

The invention provides an axial impactor, which comprises an upper joint; the driving turbine is rotationally connected to the upper joint; the driven cam is in transmission connection with the driving turbine, and the driving turbine is used for driving the driven cam to rotate; the impact hammer is connected with the driven cam through a transmission mechanism, and when the driven cam rotates, the impact hammer can be driven to reciprocate up and down in the vertical direction through the transmission mechanism; the lower connecting cylinder, the upper end of the lower connecting cylinder is connected with the upper joint, and the driving turbine, the driven cam and the impact hammer are all positioned in the lower connecting cylinder. The axial impact tool solves the problems of complex structure, poor stability and low service life of the axial impact tool in the prior art.

Description

Axial impactor

Technical Field

The invention relates to the technical field of deep well hard stratum drilling acceleration devices, in particular to an axial impactor.

Background

The current shallow oil and gas resources are increasingly exhausted, and oil and gas exploration and development progress to deep wells and ultra-deep wells. However, deep formations have been more geologic over time, with rock becoming harder as depth increases, resulting in reduced drilling efficiency, shorter bit life, longer drilling cycles, and higher drilling costs. In order to improve the mechanical drilling speed and reduce the drilling cost, an axial impactor accelerating tool is generally adopted to assist in breaking rock, namely, a impactor high-frequency hammering drilling tool is utilized to enter the rock, so that the aim of improving the drilling efficiency is fulfilled.

At present, the axial impact tool at the present stage has a complex structure and a lower service life, for example, the Chinese patent invention of a reciprocating hydraulic impactor with publication number of CN103291214A has the defect that the combined scheme of a turbine and a spring adopted by the impact principle and the common impact tools of the same type have complex structure, and the spring cannot keep continuous stability in use precision and belongs to a vulnerable part, so that the impact tool with the structure has poor stability of impact strength and service life of the tool when in use.

Disclosure of Invention

In view of the above-mentioned drawbacks of the prior art, an object of the present invention is to provide an axial impactor for solving the problems of complex structure, poor stability and low service life of the axial impact tool in the prior art.

To achieve the above and other related objects, the present invention provides an axial impactor comprising an upper joint; the driving turbine is rotationally connected to the upper joint; the driven cam is in transmission connection with the driving turbine, and the driving turbine is used for driving the driven cam to rotate; the impact hammer is connected with the driven cam through a transmission mechanism, and when the driven cam rotates, the impact hammer can be driven to reciprocate up and down in the vertical direction through the transmission mechanism; the lower connecting cylinder, the upper end of the lower connecting cylinder is connected with the upper joint, and the driving turbine, the driven cam and the impact hammer are all positioned in the lower connecting cylinder.

Preferably, a spline groove is formed in the top end of the driven cam, and a spline is formed in the lower end of the driving turbine and matched with the spline groove.

Preferably, the driven cam is cylindrical, the transmission mechanism comprises a wavy guide rail chute arranged on the circumferential surface of the driven cam, and a first connecting rod and a second connecting rod which are respectively arranged on the left side and the right side of the impact hammer, wherein two driven pulleys are embedded in the wavy guide rail chute and are respectively positioned on the left side and the right side of the driven cam, a first connecting screw rod and a second connecting screw rod are respectively arranged on the driven pulleys, the first connecting screw rod is connected with the first connecting rod, and the second connecting screw rod is connected with the second connecting rod.

Preferably, the upper joint is internally provided with a cross-shaped support, the middle part of the cross-shaped support is provided with a positioning hole, a positioning shaft is arranged in the positioning hole in a penetrating manner, the top end of the positioning shaft is provided with a positioning boss, the positioning boss is limited on the top surface of the cross-shaped support, and the driving turbine is rotationally arranged on the positioning shaft.

Preferably, the positioning boss is tapered.

Preferably, the driving turbine is rotatably arranged on the positioning shaft through a bearing.

Preferably, the lower connecting cylinder is internally provided with a limiting overcurrent plate and a sealing inner cylinder, wherein the limiting overcurrent plate comprises a middle current-limiting disc and an outer annular plate, the middle current-limiting disc is connected with the outer annular plate through a plurality of connecting rib plates, an annular launder is formed by a gap between the middle current-limiting disc and the outer annular plate, the middle current-limiting disc is rotatably arranged on the driving turbine, the diameter of the middle current-limiting disc is larger than that of the driven cam, and the outer annular plate is fixedly connected with the inner wall of the lower connecting cylinder; the top of sealed inner tube with the bottom of middle part current-limiting disc is connected, the bottom of sealed inner tube with connect the bottom plate of section of thick bamboo down to be connected, sealed inner tube middle part current-limiting disc reaches connect down and form a confined space between the bottom plate of section of thick bamboo, the driven cam with the jump bit all is located in the confined space.

Preferably, the bottom of the middle current-limiting disc is provided with a first embedded groove, the inner wall of the bottom plate of the lower connecting cylinder is provided with a second embedded groove, the top end of the sealing inner cylinder is embedded in the first embedded groove, and the bottom end of the sealing inner cylinder is embedded in the second embedded groove.

Preferably, a first internal thread is further arranged in the first embedded groove, a first external thread is arranged at the top end of the sealing inner cylinder, and the first external thread is matched with the first internal thread; the second embedded groove is internally provided with a second internal thread, the bottom end of the sealing inner cylinder is provided with a second external thread, and the second external thread is matched with the second internal thread.

Preferably, the inner wall of the bottom plate of the lower connecting cylinder is also provided with an arc-shaped groove matched with the hammer head of the impact hammer.

As described above, the axial impactor of the present invention has the following advantageous effects: when the drilling fluid is used, drilling fluid enters the impactor from the upper part of the upper joint, namely, fluid can impact the driving turbine to rotate, so that the driving turbine drives the driven cam to rotate, and the driven cam drives the impact hammer to reciprocate up and down in the vertical direction through the transmission mechanism during rotation, so that periodic axial impact force is provided through the up-down reciprocating motion of the impact hammer, and rock breaking of the drill bit is assisted. Compared with the prior art, the axial impactor disclosed by the invention has the advantages that the structure is simple, the impact hammer is driven to periodically reciprocate up and down through the cooperation of the driven cam and the transmission mechanism, and the use of a vulnerable part spring is reduced, so that stable axial impact can be continuously generated, and the service life of the axial impactor is longer; meanwhile, because the structure is simple, the number of parts in the impactor is small, the smoothness of the drilling fluid flowing in the impactor is good, and the fluid energy utilization rate is high; meanwhile, the impactor disclosed by the invention has no electronic element and fragile workpieces, so that the tripping times are greatly reduced, and the drilling efficiency can be further improved.

Drawings

Fig. 1 shows a schematic structural view of an axial impactor provided by the invention.

Fig. 2 shows an exploded view of an axial impactor provided by the present invention.

Fig. 3 shows a front view of an active turbine provided by the present invention.

Fig. 4 shows a front view of a follower cam provided by the present invention.

Fig. 5 is a top view of the lower socket according to the present invention.

Fig. 6 is a schematic structural diagram of a limiting flow-through plate according to the present invention.

Fig. 7 shows a perspective view of the interior of the lower barrel of the axial impactor provided by the invention.

Fig. 8 shows a perspective view of an axial impactor provided by the invention.

Description of the reference numerals

10. Upper joint 11 lower joint cylinder

101. Cross support 1011 locating hole

102. Positioning boss of positioning shaft 1021

111. The bottom plate 1110 is second embedded with a groove

1111. Arc groove 1112 connecting rib

20. Spline of driving turbine 21

30. Spline groove of driven cam 31

32. First connecting screw of wavy guide rail chute 331

332. Second connecting screw 40 impact hammer

41. First connecting rod 42 second connecting rod

12. Middle current limiting disc of limiting overcurrent plate 121

122. External annular plate 1211 annular launder

1210. First embedded groove of connecting rib 1212

13. Sealing the inner cylinder 130 enclosure

Detailed Description

Other advantages and effects of the present invention will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present invention with reference to specific examples. The invention may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present invention.

In the description of the present invention, unless specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly coupled, detachably coupled, integrally connected, mechanically coupled, electrically coupled, directly coupled, or coupled via an intermediate medium, or in communication between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

In the description of the present invention, it should be understood that the terms "center," "longitudinal," "transverse," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in the present invention as indicated by the orientation or positional relationship shown in the drawings, merely for convenience of description and to simplify the description, but do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be construed as limiting the invention. Furthermore, the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

Please refer to fig. 1 to 8. It should be noted that, the illustrations provided in the present embodiment merely illustrate the basic concept of the present invention by way of illustration, and only the components related to the present invention are shown in the drawings and are not drawn according to the number, shape and size of the components in actual implementation, and the form, number and proportion of the components in actual implementation may be arbitrarily changed, and the layout of the components may be more complex.

The invention provides an axial impactor, which is particularly shown in fig. 1-2, and comprises an upper joint 10, a driving turbine 20, a driven cam 30, an impact hammer 40 and a lower joint barrel 11, wherein the driving turbine 20 is rotationally connected to the upper joint 10, the driven cam 30 is in transmission connection with the driving turbine 20, namely the driving turbine 20 is used for driving the driven cam 30 to rotate, the impact hammer 40 is connected with the driven cam 30 through a transmission mechanism, and when the driven cam 30 rotates, the impact hammer 40 can be driven to reciprocate up and down in the vertical direction through the transmission mechanism; the upper end of the lower connecting cylinder 11 is connected with the upper joint 10, and the driving turbine 20, the driven cam 30 and the impact hammer 40 are all positioned inside the lower connecting cylinder 11.

When the axial impactor disclosed by the invention is used, the bottom of the lower connecting cylinder 11 can be directly connected with a drill bit, drilling fluid enters the interior of the impactor from the upper part of the upper joint 10, namely, fluid can impact the driving turbine 20 to rotate, so that the driving turbine 20 drives the driven cam 30 to rotate, the driven cam 30 drives the impact hammer 40 to reciprocate up and down in the vertical direction through the transmission mechanism during rotation, and periodic axial impact force is provided through the up and down reciprocation of the impact hammer 40 so as to assist the drill bit in rock breaking. Compared with the prior art, the axial impactor disclosed by the invention has the advantages that the structure is simple, the impact hammer is driven to periodically reciprocate up and down through the cooperation of the driven cam and the transmission mechanism, and the use of a vulnerable part spring is reduced, so that stable axial impact can be continuously generated, and the service life of the axial impactor is longer; meanwhile, because the structure is simple, the number of parts in the impactor is small, the smoothness of the drilling fluid flowing in the impactor is good, and the fluid energy utilization rate is high; meanwhile, the impactor disclosed by the invention has no electronic element and fragile workpieces, so that the tripping times are greatly reduced, and the drilling efficiency can be further improved.

Preferably, in the present embodiment, the driving turbine 20 and the driven cam 30 are driven by spline coupling, specifically, as shown in fig. 2 and 3, a spline groove 31 is provided in the top end of the driven cam 30, a spline 21 is provided at the lower end of the driving turbine 20, and the spline 21 on the driving turbine 20 is matched with the spline groove 31 on the driven cam 30. By spline driving, the driving stability is ensured, so that the up-and-down reciprocating motion stability of the impact hammer 40 is ensured, and more stable periodic impact motion can be provided, so that the probability of failure of the impactor is naturally reduced.

Further, as shown in fig. 1 to 4, in the present embodiment, the driven cam 30 is cylindrical, the transmission mechanism includes a wavy guide rail chute 32 disposed on the circumferential surface of the driven cam 30, and a first connecting rod 41 and a second connecting rod 42 disposed on the left and right sides of the impact hammer 40, that is, the first connecting rod 41 is disposed on the left side of the impact hammer 40, the second connecting rod 42 is disposed on the right side of the impact hammer 40, specifically, two driven pulleys (not shown) are embedded in the wavy guide rail chute 32, and are disposed on the left and right sides of the driven cam 30, that is, the two driven pulleys correspond to the positions of the first connecting rod 41 and the second connecting rod 42 on the impact hammer 40, and a first connecting screw 331 and a second connecting screw 332 are disposed on the two driven pulleys, respectively, wherein the first connecting screw 331 is connected with the first connecting rod 41 on the impact hammer 40, and the second connecting screw 332 is connected with the second connecting rod 42 on the impact hammer 40.

During operation, when the driven cam 30 is driven by the driving turbine 20 to rotate relative to the impact hammer 40, the driven pulley is driven to slide up and down relative to the driven cam 30 in the wavy guide rail chute 32 on the circumferential surface of the driven cam 30, so as to generate up-and-down linear motion, and the up-and-down linear motion of the driven pulley drives the impact hammer 40 to do the same up-and-down linear motion through the first connecting rod 41 and the second connecting rod 42, so that the axial reciprocating impact motion of the impact hammer 40 is realized, and the impact force is provided for the drill bit arranged at the bottom of the lower connecting barrel 11 to assist in rock breaking. Through the structural design, namely, a cam type transmission mechanism is formed by the wavy guide rail sliding groove 32 on the circumferential surface of the cylindrical driven cam 30 and the driven pulley embedded in the wavy guide rail sliding groove 32, the rotary motion of the driven cam 30 is converted into the reciprocating linear motion of the driven pulley, and the driven pulley drives the impact hammer 40 to realize periodical axial impact motion. The structure has great bearing capacity, so that the impactor is more stable in working, the service life is obviously prolonged, and the cam type transmission is more precise than other transmissions, so that the mechanical loss can be greatly reduced, and stable and efficient high-frequency impact can be realized.

Specifically, in the actual operation process, the height difference between the lowest point and the highest point of the wavy guide rail chute 32 on the circumferential surface of the driven cam 30 can be changed according to the drilling requirement, so as to change the impact frequency of the impactor, and the device has the advantages of wide application range, strong flexibility and low requirement on the weight on drilling.

Further, as shown in fig. 1 and 2, in the present embodiment, a cross-shaped support 101 is disposed in the upper joint 10, a positioning hole 1011 is disposed in the middle of the cross-shaped support 101, a positioning shaft 102 is disposed in the positioning hole 1011 in a penetrating manner, a positioning boss 1021 is disposed at the top end of the positioning shaft 102, the positioning boss 1021 is limited on the top surface of the cross-shaped support 101, i.e. the diameter of the positioning boss 1021 is larger than that of the positioning hole 1011, the bottom surface of the positioning boss 1021 is in contact with the top surface of the cross-shaped support 101, and the driving turbine 20 is rotatably disposed on the positioning shaft 102, i.e. in the present embodiment, the driving turbine 20 is rotatably connected to the upper joint 10 through the positioning shaft 102. Through this structural design, simple structure, and through setting up the cross support in the top connection 10 inside, when filling drilling fluid to the impactor inside from top connection 10 upper portion, this cross support 101 can better break up drilling fluid for drilling fluid is with annular scattering impact initiative turbine 20 uniformly. Specifically, in the present embodiment, the driving turbine 20 is rotatably disposed on the positioning shaft 102 through a bearing.

Further, in order to enable the drilling fluid to be dispersed evenly in a ring shape, it is preferable that, as shown in fig. 2, the positioning boss 1021 at the top end of the positioning shaft 102 is tapered, and in particular, the tapered positioning boss 1021 is screwed with the fixed end of the positioning shaft 102.

Further, in order to avoid the impact hammer 40 that reciprocates up and down from being affected by the downward flowing drilling fluid when the drilling fluid is filled into the impactor (the flow passage space formed inside the upper joint and the lower joint barrel), it is preferable that, as shown in fig. 7 and 8, in this embodiment, a limiting flow-through plate 12 and a sealing inner barrel 13 are further disposed inside the lower joint barrel 11, wherein the limiting flow-through plate 12 includes a middle flow-limiting disc 121 and an outer annular plate 122, specifically, the middle flow-limiting disc 121 is connected with the outer annular plate 122 through a plurality of connecting ribs 1210, specifically, as shown in fig. 6, four connecting ribs 1210 protruding radially outwards are uniformly disposed on the outer circumferential surface of the middle flow-limiting disc 121, the outer annular plate 122 is connected with the four connecting ribs 1210, so that the gap between the middle flow-limiting disc 121 and the outer annular plate 122 forms an annular flow groove 1211, specifically, the middle flow-limiting disc 121 is rotatably disposed on the driving turbine 20, the outer annular plate 122 is fixedly connected with the inner wall of the lower joint barrel 11, and the diameter of the middle flow-limiting disc 121 is larger than the diameter of the driven cam 30; the top end of the inner sealing cylinder 13 is connected with the bottom of the middle flow-limiting disc 121, and the bottom end of the inner sealing cylinder 13 is connected with the bottom plate 111 of the lower connecting cylinder 11, so that a closed space 130 is formed among the inner sealing cylinder 13, the middle flow-limiting disc 121 and the bottom plate 111 of the lower connecting cylinder 11, and the driven cam 30 and the impact hammer 40 are both positioned in the closed space 130.

In operation, since the limiting flow-limiting plate 12 is disposed in the lower connecting cylinder 11, that is, the diameter of the middle flow-limiting disc 121 on the limiting flow-limiting plate 12 is larger than that of the driven cam 30, the drilling fluid flowing down from the upper joint 10 is blocked by the middle flow-limiting disc 121 so that the drilling fluid flows down from the annular groove 1211 formed between the middle flow-limiting disc 121 and the outer annular plate 122, and the sealed inner cylinder 13 is disposed below the middle flow-limiting disc 121, and the driven cam 30 and the impact hammer 40 are enclosed in the enclosed space 130 by the sealed inner cylinder 13, so that the impact of the drilling fluid on the driven cam and the impact hammer is avoided, and the impact operation of the impactor is more stable.

Further, as shown in fig. 5 to 8, in the present embodiment, a first embedded groove 1212 is provided at the bottom of the middle flow-limiting disc 121, a second embedded groove 1110 is provided on the inner wall of the bottom plate 111 of the lower receiving cylinder 11, the top end of the inner sealing cylinder 13 is embedded in the first embedded groove 1212 of the middle flow-limiting disc 121, and the bottom end of the inner sealing cylinder 13 is embedded in the second embedded groove 1110 of the bottom plate 111 of the lower receiving cylinder 11. Through the connection of inlaying the mode of establishing, easy dismounting and also can improve the leakproofness of enclosure 130.

As a preferred way, in order to further improve the tightness of the enclosed space 130, in this embodiment, a first internal thread is further provided inside the first embedded groove 1212, the top end of the inner sealing cylinder 13 is provided with a first external thread, and the first external thread is matched with the first internal thread, that is, while the top end of the inner sealing cylinder 13 is embedded in the first embedded groove 1212, the top end of the inner sealing cylinder 13 is also in threaded connection with the first embedded groove, so as to further improve the tightness of the joint; similarly, the second embedded groove 1110 is internally provided with a second internal thread, the bottom end of the inner sealing cylinder 13 is provided with a second external thread, and the second external thread is matched with the second internal thread, so that the tightness of the joint at the bottom of the inner sealing cylinder 13 is further improved.

Further, in order to concentrate the impact force provided by the impact hammer 40, as shown in fig. 5 and 8, in this embodiment, an arc-shaped groove 1111 adapted to the hammer head of the impact hammer 40 is preferably further provided on the inner wall of the bottom plate 111 of the lower socket 11.

Specifically, as shown in fig. 5, the bottom of the lower connecting cylinder 11 is in an unsealed structure, that is, the diameter of the bottom plate 111 of the lower connecting cylinder 11 is smaller than that of the lower connecting cylinder 11, the bottom plate 111 is connected with the inner wall of the lower connecting cylinder 11 through a plurality of connecting ribs 1112 extending along radial direction, so that a flow passage is formed between the bottom plate 111 and the inner wall of the lower connecting cylinder 11, and the drilling fluid filled in the impactor from the upper joint 10 to the bottom of the lower connecting cylinder 11 finally flows out.

In summary, the axial impactor disclosed by the invention is suitable for an ultralow-pressure fluid driving occasion, and the use of a vulnerable part spring is reduced, so that stable axial impact can be continuously generated, and the service life of the axial impactor is longer; meanwhile, because the structure is simple, the number of parts in the impactor is small, the smoothness of the drilling fluid flowing in the impactor is good, and the fluid energy utilization rate is high; the impactor disclosed by the invention also has no electronic element and fragile workpieces, so that the tripping times are greatly reduced, and the drilling efficiency can be further improved. Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.

The above embodiments are merely illustrative of the principles of the present invention and its effectiveness, and are not intended to limit the invention. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is intended that all equivalent modifications and variations of the invention be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.

Claims (10)

1. An axial impactor, comprising:

an upper joint;

the driving turbine is rotationally connected to the upper joint;

the driven cam is in transmission connection with the driving turbine, and the driving turbine is used for driving the driven cam to rotate;

the impact hammer is connected with the driven cam through a transmission mechanism, and when the driven cam rotates, the impact hammer can be driven to reciprocate up and down in the vertical direction through the transmission mechanism;

the lower connecting cylinder, the upper end of the lower connecting cylinder is connected with the upper joint, and the driving turbine, the driven cam and the impact hammer are all positioned in the lower connecting cylinder.

2. An axial impactor according to claim 1, wherein said driven cam has a spline groove in the interior of the top end thereof, and said driving turbine has a spline at the lower end thereof, said spline being engaged with said spline groove.

3. The axial impactor of claim 1, wherein the driven cam is cylindrical, the transmission mechanism comprises a wavy guide rail chute arranged on the circumferential surface of the driven cam, and a first connecting rod and a second connecting rod respectively arranged on the left side and the right side of the impact hammer, wherein two driven pulleys are embedded in the wavy guide rail chute and are respectively arranged on the left side and the right side of the driven cam, a first connecting screw rod and a second connecting screw rod are respectively arranged on the two driven pulleys, the first connecting screw rod is connected with the first connecting rod, and the second connecting screw rod is connected with the second connecting rod.

4. The axial impactor of claim 1, wherein a cross-shaped support is arranged in the upper joint, a positioning hole is formed in the middle of the cross-shaped support, a positioning shaft is arranged in the positioning hole in a penetrating mode, a positioning boss is arranged at the top end of the positioning shaft and limited on the top surface of the cross-shaped support, and the driving turbine is rotatably arranged on the positioning shaft.

5. The axial impactor of claim 4, wherein said positioning boss is tapered.

6. The axial impactor of claim 4, wherein said drive turbine is rotatably mounted to said positioning shaft by bearings.

7. The axial impactor of claim 1, wherein a limiting overflow plate and a sealing inner cylinder are further arranged in the lower connecting cylinder, the limiting overflow plate comprises a middle current limiting disc and an outer annular plate, the middle current limiting disc is connected with the outer annular plate through a plurality of connecting ribs, an annular launder is formed by a gap between the middle current limiting disc and the outer annular plate, the middle current limiting disc is rotatably arranged on the driving turbine, the diameter of the middle current limiting disc is larger than that of the driven cam, and the outer annular plate is fixedly connected with the inner wall of the lower connecting cylinder; the top of sealed inner tube with the bottom of middle part current-limiting disc is connected, the bottom of sealed inner tube with connect the bottom plate of section of thick bamboo down to be connected, sealed inner tube middle part current-limiting disc reaches connect down and form a confined space between the bottom plate of section of thick bamboo, the driven cam with the jump bit all is located in the confined space.

8. The axial impactor of claim 7, wherein a first embedded groove is formed in the bottom of the middle flow limiting disc, a second embedded groove is formed in the inner wall of the bottom plate of the lower connecting cylinder, the top end of the inner sealing cylinder is embedded in the first embedded groove, and the bottom end of the inner sealing cylinder is embedded in the second embedded groove.

9. The axial impactor of claim 8, wherein a first internal thread is further provided in the first embedded groove, a first external thread is provided at the top end of the inner sealing cylinder, and the first external thread is matched with the first internal thread; the second embedded groove is internally provided with a second internal thread, the bottom end of the sealing inner cylinder is provided with a second external thread, and the second external thread is matched with the second internal thread.

10. The axial impactor of claim 1, wherein the inner wall of the bottom plate of the lower connecting cylinder is further provided with an arc-shaped groove matched with the hammer head of the impact hammer.