A composite impact screw

Abstract

A composite impact screw rod is composed of a bypass valve assembly, a motor assembly, a universal shaft assembly, a torsional impact assembly, an axial impact assembly and a transmission shaft assembly; the bypass valve assembly is used to control the flow direction of the drilling fluid; the motor assembly converts the liquid pressure energy of the drilling fluid into mechanical energy; the universal shaft assembly is used to convert the eccentric rotational motion generated by the motor assembly into a fixed-axis rotational motion; the torsional impact assembly converts the fixed-axis rotational motion into a periodic circumferential swing through an inner cam and an outer cam; the axial impact assembly converts the fixed-axis rotational motion into a periodic up and down impact motion through an upper cam and a lower cam; the transmission shaft assembly is used to transmit the fixed-axis rotational motion to a drill bit for rotating and breaking rocks; the present invention solves the problems of shallow drill bit penetration depth and serious stick-slip vibration of the drill bit in deep well drilling in the prior art, and reduces the problems of insufficient drill bit penetration depth and serious stick-slip vibration of the drill bit through the combined action of periodic circumferential swing and axial impact, thereby improving the drilling efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of oil drilling, in particular to a composite impact screw. Background Art

[0002] As oil and gas production gradually develops towards complex wells such as deep wells and ultra-deep wells, the problems of insufficient rock-breaking torque of drill bits in deep hard rock formations, shallow penetration depth of drill bits and severe stick-slip vibration are becoming more and more prominent. Increasing drilling pressure can increase the penetration depth of drill bits, but it will aggravate the stick-slip vibration phenomenon of drill bits; reducing drilling pressure can slow down the stick-slip vibration phenomenon to a certain extent, but it will cause problems such as insufficient penetration depth of drill bits and low overall drilling efficiency; the application of axial impactors increases the penetration depth of drill bits and improves drilling efficiency to a certain extent, but it cannot alleviate the insufficient rock-breaking torque and stick-slip vibration phenomenon of drill bits in deep drilling; the application of torsional impactors slows down the stick-slip vibration phenomenon of drill bits in deep drilling to a certain extent, but it cannot effectively solve the problem of insufficient penetration depth of drill bits. Solving the problems of insufficient penetration depth of drill bits, insufficient rock-breaking torque and slowing down the stick-slip vibration phenomenon of drill bits in deep drilling is of great significance to improving the overall drilling efficiency of drilling machinery.

[0003] In view of the above problems, a composite impact screw is proposed. The tool uses a motor assembly to convert the drilling fluid pressure energy into mechanical energy rotating around a fixed axis, drives the torsional impact assembly to produce periodic torsional impact and drives the axial impact assembly to produce periodic axial impact. Under the combined effect of periodic torsional impact and axial impact, it can effectively alleviate the problems of insufficient drill bit penetration depth, insufficient rock breaking torque near the drill bit, and obvious stick-slip vibration of the drill bit. Summary of the invention

[0004] The purpose of the present invention is to provide a composite impact screw to solve the problems existing in the existing drilling technology, such as insufficient penetration depth of the drill bit, severe stick-slip vibration of the drill bit causing increased wear of the drill tool, and low drilling efficiency. The tool converts part of the liquid pressure energy of the drilling fluid into periodic torsional impact and axial impact, thereby effectively improving the drilling efficiency of the drilling machinery.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is:

[0006] A composite impact screw rod is composed of a bypass valve assembly, a motor assembly, a universal shaft assembly, a torsional impact assembly, an axial impact assembly and a transmission shaft assembly; the bypass valve assembly is used to control the flow direction of the drilling fluid; the motor assembly is placed below the bypass valve assembly and is used to convert the liquid pressure energy of the drilling fluid into the rotational mechanical energy of the motor assembly; the universal shaft assembly is placed below the motor assembly and is used to convert the eccentric rotational motion generated by the motor assembly into a fixed-axis rotational motion; the torsional impact assembly is placed below the universal shaft assembly and converts the fixed-axis rotational motion into the periodic circumferential swing of the outer cam through the joint action of the inner cam and the outer cam; the axial impact assembly is placed below the torsional impact assembly and converts the fixed-axis rotational motion into the periodic up and down impact of the upper cam through the joint action of the upper cam and the lower cam; the torsional impact assembly and the axial impact assembly are placed in the middle of the transmission shaft assembly and the transmission shaft assembly is used to transmit the fixed-axis rotational motion to the drill bit for rotating and breaking rocks.

[0007] The bypass valve assembly consists of a bypass valve housing, an upper valve core, a second spring and a lower valve core. The bypass valve housing is connected to the upper housing of the motor assembly through threads.

[0008] The motor assembly consists of a motor assembly upper shell, an anti-drop cap, an anti-drop rod, an anti-drop retaining ring, a motor assembly lower shell, a screw stator and a screw rotor; when the drilling fluid passes through the bypass valve assembly and flows through the motor assembly, the liquid pressure energy of the drilling fluid is converted into the rotational mechanical energy of the screw rotor.

[0009] The universal joint shaft assembly is composed of a universal joint shaft housing and a ball universal joint shaft assembly; the upper part of the universal joint shaft housing is connected to the lower part of the motor assembly lower shell by threads; the upper part of the ball universal joint shaft assembly is connected to the lower part of the screw rotor by threads; the eccentric rotational motion of the screw rotor is converted into fixed axis rotational motion.

[0010] The torsion impact assembly consists of a torsion impact shell, an inner cam, an outer cam, a slider, a pin and a roller; the torsion impact shell is connected to the lower part of the transmission upper shell by threads; the torsion impact shell is provided with a first impact block and a first slide groove; the number of the first impact blocks is 2 to 4; the number of the first slide grooves is consistent with the number of the first impact blocks; the inner cam is connected to the transmission shaft by threads; the inner cam is provided with a first step surface and a first cam groove; the first cam groove is provided with a push section and a return section; the number of the push section and the return section is consistent with the number of the first impact block; the outer cam is installed outside the inner cam and is coaxial with the inner cam; the outer cam is provided with a second impact block and a second cam groove; the number of the second impact blocks is consistent with the first impact block; the second The cam groove is a discontinuous inclined groove, and the number is the same as that of the first impact block; the slider is placed in the first slide groove, and the roller is connected to the slider through the pin; the roller is installed in the first cam groove; the pin passes through the second cam groove; when the drilling flow passes through the motor assembly, the drilling fluid liquid pressure energy is converted into the rotational mechanical energy of the motor assembly and transmitted to the transmission shaft to drive the transmission shaft to rotate, the inner cam is connected to the transmission shaft through a thread, and rotates with the transmission shaft. When the inner cam rotates, the slider, the pin, and the roller are pushed to perform periodic up and down movements as a whole under the joint action of the first cam groove and the slide groove; under the joint action of the pin and the second cam groove, the outer cam is pushed to perform periodic circumferential swings, so that the second impact block periodically impacts the first impact block to achieve periodic torsional impact;

[0011] The axial impact assembly is mainly composed of an axial impact shell, a first retaining ring, a first compression spring, a positioning screw, an upper cam, a lower cam and a flat key; the axial impact shell is provided with a first abutment and an annular array of threaded holes; the number of the annular array of threaded holes is 3 to 6; the upper cam is provided with an annular array of upper cam teeth and a first groove; the number of the upper cam teeth is 3 to 6; the number of the first grooves is consistent with the number of the annular array of threaded holes; one end of the first compression spring abuts against the first abutment, and the other end abuts against the top of the upper cam; the upper cam is circumferentially fixed in the axial impact shell by a positioning screw, and can slide axially along the positioning screw, with a sliding stroke of 20 to 50 mm; the lower cam is provided with lower cam teeth, a first keyway and a second step surface; the number of the lower cam teeth is the same as the number of the upper cam teeth The number of the first keyways is 1 to 3; the lower cam is circumferentially fixed to the transmission shaft by a flat key and rotates with the transmission shaft; the upper end of the first retaining ring abuts against the bottom of the inner cam, and the lower end abuts against the second step surface of the lower cam; when the drilling fluid flows through the motor assembly to convert the drilling fluid liquid pressure energy into rotational mechanical energy and transmit it to the transmission shaft assembly to drive the transmission shaft to rotate, the lower cam rotates with the transmission shaft, and under the joint action of the lower cam teeth and the upper cam teeth, the upper cam is periodically pushed to reciprocate up and down. When the upper cam moves upward, the first compression spring is compressed to convert the rotational mechanical energy of the transmission shaft into the elastic potential energy of the first compression spring for storage; when the upper cam moves downward, under the joint action of the upper cam's own weight and the first compression spring, the upper cam is pushed to accelerate downward to impact the lower cam to achieve periodic reciprocating up and down impacts.

[0012] The transmission shaft assembly consists of an upper stabilizing bearing group, an upper thrust ball bearing group, a transmission upper housing, a second retaining ring, a lower stabilizing bearing group, a transmission lower housing and a transmission shaft; the upper part of the transmission upper housing is threadedly connected to the lower part of the universal joint housing, and the lower part of the transmission upper housing is threadedly connected to the upper part of the torsional impact housing; the upper part of the transmission lower housing is threadedly connected to the lower part of the axial impact housing; the upper part of the transmission shaft is threadedly connected to the lower part of the ball universal joint shaft assembly.

[0013] Beneficial effects of the present invention:

[0014] The present invention provides a composite impact screw, which utilizes a motor assembly to convert drilling fluid liquid pressure energy into rotational mechanical energy, a portion of which is transmitted to a torsional impact assembly to drive an outer cam to periodically reciprocate and swing to generate a torsional impact; a portion of which is transmitted to an axial impact assembly to drive an upper cam to periodically compress a first compression spring to generate a periodic reciprocating up and down impact. Under the combined action of periodic torsional impact and axial impact, the drill bit penetration depth is increased, the stick-slip vibration phenomenon of the drill bit is slowed down, and the drilling efficiency of the drilling machinery is effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of the device of the present invention;

[0016] Figure 2 It is a cross-sectional schematic diagram of the torsional impact assembly of the device of the present invention;

[0017] Figure 3 It is a schematic diagram of the structure of the axial impact assembly of the device of the present invention;

[0018] Figure 4 It is a structural schematic diagram of the upper cam of the device of the present invention;

[0019] Figure 5 It is a structural schematic diagram of the lower cam of the device of the present invention;

[0020] Figure 6 It is a schematic diagram of the mechanism of the inner cam of the device of the present invention;

[0021] Figure 7 It is a structural schematic diagram of the outer cam of the device of the present invention;

[0022] Figure 8 It is a schematic structural diagram of the torsion punch shell of the device of the present invention.

[0023] In the figure: 1. bypass valve assembly; 11. bypass valve housing; 12. upper valve core; 13. second spring; 14. lower valve core; 2. motor assembly; 21. upper housing of motor assembly; 22. anti-drop cap; 23. anti-drop retaining ring; 24. anti-drop rod; 25. lower housing of motor assembly; 26. screw stator; 27. screw rotor; 3. universal shaft assembly; 31. universal shaft housing; 32. ball universal shaft assembly; 4. torsional impact assembly; 41. torsional impact housing; 411. first impact block; 412. first slide groove; 42. inner cam; 421. first step surface; 422. first cam groove; 43. outer cam; 431. first Second impact block; 432, second cam groove; 44, slider; 45, pin; 46, roller; 5, axial impact assembly; 51, axial impact housing; 52, first retaining ring; 53, first compression spring; 54, positioning screw; 55, upper cam; 551, upper cam tooth; 552, first groove; 56, lower cam; 561, lower cam tooth; 562, first keyway; 563, second step surface; 57, flat key; 6, transmission shaft assembly; 61, upper centering bearing group; 62, upper thrust ball bearing group; 63, transmission upper housing; 64, second retaining ring; 65, transmission lower housing; 66, lower centering bearing group; 67, transmission shaft.

[0024] Specific implementation method

[0025] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention is further described below in conjunction with the accompanying drawings. In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", "end face" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0026] like Figures 1 to 8 As shown, this embodiment provides a composite impact screw, which is mainly composed of a bypass valve assembly 1, a motor assembly 2, a universal shaft assembly 3, a torsional impact assembly 4, an axial impact assembly 5 and a transmission shaft assembly 6; the bypass valve assembly 1 is used to control the flow direction of the drilling fluid; the motor assembly 2 is placed below the bypass valve assembly 1, and is used to convert the liquid pressure energy of the drilling fluid into the rotational mechanical energy of the motor assembly 2; the universal shaft assembly 3 is placed below the motor assembly 2, and is used to convert the eccentric rotational motion generated by the motor assembly 2 into a fixed axis rotational motion ; The torsional impact assembly 4 is placed below the universal shaft assembly 3, and the fixed-axis rotational motion is converted into the periodic circumferential swing of the outer cam 43 through the joint action of the inner cam 42 and the outer cam 43; the axial impact assembly 5 is placed below the torsional impact assembly 4, and the fixed-axis rotational motion is converted into the periodic up and down impact of the upper cam 55 through the joint action of the upper cam 55 and the lower cam 56; the torsional impact assembly 4 and the axial impact assembly 5 are placed in the middle of the transmission shaft assembly 6, and the transmission shaft assembly 6 is used to transmit the fixed-axis rotational motion to the drill bit for rotating and breaking rocks.

[0027] As a preferred solution, the bypass valve assembly 1 is composed of a bypass valve housing 11, an upper valve core 12, a second spring 13 and a lower valve core 14. The bypass valve housing 11 is connected to the upper housing 21 of the motor assembly through threads.

[0028] As a preferred solution, the motor assembly 2 is composed of a motor assembly upper shell 21, an anti-drop cap 22, an anti-drop rod 23, an anti-drop retaining ring 24, a motor assembly lower shell 25, a screw stator 26 and a screw rotor 27; when the drilling fluid passes through the bypass valve assembly 1 and flows through the motor assembly 2, the liquid pressure energy of the drilling fluid is converted into the rotational mechanical energy of the screw rotor 27.

[0029] As a preferred solution, the universal joint assembly 3 is composed of a universal joint housing 31 and a ball universal joint assembly 32; the upper part of the universal joint housing 31 is threadedly connected to the lower part of the motor assembly lower housing 25; the upper part of the ball universal joint assembly 32 is threadedly connected to the lower part of the screw rotor 27; the eccentric rotational motion of the screw rotor 27 is converted into fixed-axis rotational motion.

[0030] As a preferred solution, the torsion impact assembly 4 is composed of a torsion impact shell 41, an inner cam 42, an outer cam 43, a slider 44, a pin 45 and a roller 46; the torsion impact shell 41 is connected to the lower part of the transmission upper shell 61 by threads; the torsion impact shell 41 is provided with a first impact block 411 and a first slide groove 412; the number of the first impact blocks 411 is 2 to 4; the number of the first slide grooves 412 is consistent with the number of the first impact blocks 411; the inner cam 42 is connected to the transmission shaft 67 by threads; the inner cam 42 is provided with a first step surface 421 and a first cam groove 422; the first cam groove 422 is provided with a push section and a return section; the number of the push section and the return section is consistent with the first impact block 411; the outer cam 43 is installed outside the inner cam 42 and is coaxial with the inner cam 42; the outer cam 43 is provided with a second impact block 431 and a second cam groove 432; the number of the second impact block 431 is consistent with the number of the first impact block 411 The second cam groove 432 is a discontinuous inclined groove, and the number is consistent with the first impact block 411; the slider 44 is placed in the first slide groove 412, and the roller 46 is connected to the slider 44 through the pin 45; the roller 46 is installed in the first cam groove 422; the pin 45 passes through the second cam groove 432; when the drilling flow passes through the motor assembly 2, the drilling fluid liquid pressure energy is converted into the rotational mechanical energy of the motor assembly 2 and transmitted to the transmission shaft 67 to drive the transmission shaft 67 to rotate, and the inner cam 42 is connected to the transmission shaft 67 through a thread and rotates with the transmission shaft 67. When the inner cam 42 rotates, the slider 44, the pin 45, and the roller 46 are pushed to perform periodic up and down movements as a whole under the joint action of the first cam groove 422 and the first slide groove 412; under the joint action of the pin 45 and the second cam groove 532, the outer cam 43 is pushed to perform periodic circumferential swing, so that the second impact block 431 periodically impacts the first impact block 411 to achieve periodic torsional impact;

[0031] As a preferred solution, the axial impact assembly 5 is mainly composed of an axial impact shell 51, a first retaining ring 52, a first compression spring 53, a positioning screw 54, an upper cam 55, a lower cam 56 and a flat key 57; the axial impact shell 51 is provided with a first abutment 501 and an annular array of threaded holes 512; the number of the annular array of threaded holes 512 is 3 to 6; the upper cam 55 is provided with an annular array of upper cam teeth 551 and a first groove 552; the number of the upper cam teeth 551 is 3 to 6; the number of the first grooves 552 is consistent with the number of the annular array of threaded holes 512; one end of the first compression spring 53 abuts against the first abutment 501, and the other end abuts against the top of the upper cam 55; the upper cam 55 is circumferentially fixed in the axial impact shell 51 by the positioning screw 54, and can slide axially along the positioning screw 54, and the sliding stroke is 20 to 50 mm; the lower cam 56 is provided with a lower cam tooth 561, a first keyway 562 and a second step surface 563; the lower cam tooth The number of the first key grooves 562 is the same as that of the upper cam teeth 551; the number of the first key grooves 562 is 1 to 3; the lower cam 56 is circumferentially fixed to the transmission shaft 67 by the flat key 57 and rotates with the transmission shaft 67; the upper end of the first retaining ring 52 abuts against the lower side of the inner cam 42, and the lower end abuts against the second step surface 563 of the lower cam 56; when the drilling fluid flows through the motor assembly 2 to convert the drilling fluid liquid pressure energy into rotational mechanical energy and transmit it to the transmission assembly 6 to drive the transmission shaft 67 to rotate, the lower cam 56 follows It rotates together with the transmission shaft 67, and under the joint action of the lower cam teeth 561 and the upper cam teeth 551, the upper cam 55 is periodically pushed to reciprocate up and down. When the upper cam 55 moves upward, the first compression spring 53 is compressed to convert the rotational mechanical energy of the transmission shaft 67 into elastic potential energy for storage in the first compression spring 53; when the upper cam 55 moves downward, under the joint action of its own weight and the first compression spring 53, the upper cam 55 is pushed to accelerate downward to impact the lower cam 56 to achieve periodic reciprocating up and down impact.

[0032] As a preferred solution, the transmission shaft assembly 6 is composed of an upper straightening bearing group 61, an upper thrust ball bearing group 62, a transmission upper shell 63, a second retaining ring 64, a lower straightening bearing group 65, a transmission lower shell 66 and a transmission shaft 67; the upper part of the transmission upper shell 62 is threadedly connected to the lower part of the universal joint housing 31, and the lower part of the transmission upper shell 63 is threadedly connected to the upper part of the torsional impact housing 41; the upper part of the transmission lower shell 66 is threadedly connected to the lower part of the axial impact housing 51; the upper part of the transmission shaft 67 is threadedly connected to the lower part of the ball universal joint shaft assembly 32.

[0033] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A composite impact screw, comprising a bypass valve assembly (1), a motor assembly (2), a universal shaft assembly (3), a torsional impact assembly (4), an axial impact assembly (5) and a transmission shaft assembly (6); the bypass valve assembly (1) is used to control the flow direction of drilling fluid; the motor assembly (2) is arranged below the bypass valve assembly (1) and is used to convert the liquid pressure energy of the drilling fluid into the rotational mechanical energy of the motor assembly (2); the universal shaft assembly (3) is arranged below the motor assembly (2) and is used to convert the eccentric rotational motion generated by the motor assembly (2) into the fixed axis rotational motion; the torsional impact assembly (4) is used to control the flow direction of the drilling fluid; the motor assembly (2) is used to convert the eccentric rotational motion generated by the motor assembly (2) into the fixed axis rotational motion; the The impact assembly (4) is arranged below the universal shaft assembly (3), and the fixed-axis rotational motion is converted into the periodic circumferential swing of the outer cam (43) through the joint action of the inner cam (42) and the outer cam (43); the axial impact assembly (5) is arranged below the torsion impact assembly (4), and the fixed-axis rotational motion is converted into the periodic up and down impact of the upper cam (55) through the joint action of the upper cam (55) and the lower cam (56); the torsion impact assembly (4) and the axial impact assembly (5) are arranged in the middle of the transmission shaft assembly (6), and the transmission shaft assembly (6) is used to transmit the fixed-axis rotational motion to the drill bit for rotating and breaking rocks; The torsion impact assembly (4) is composed of a torsion impact housing (41), an inner cam (42), an outer cam (43), a slider (44), a pin (45) and a roller (46); the torsion impact housing (41) is connected to the lower part of the transmission upper housing (63) by means of threads; the torsion impact housing (41) is provided with a first impact block (411) and a first slide groove (412); the inner cam (42) is connected to the transmission shaft (67) by means of threads; the inner cam (42) is provided with a first step surface (421) and a first cam groove (422); the first cam groove (422) is provided with a push section and a return section; the outer cam (43) is installed outside the inner cam (42) and is coaxial with the inner cam (42); the outer cam (43) is provided with a second impact block (431) and a second cam groove (432); the slider (44) is placed in the first slide groove (412), and the roller (46) is provided with a first impact block (431) and a second cam groove (432); (45) is connected to the slider (44); the roller (46) is installed in the first cam groove (422); the pin (45) is installed in the second cam groove (432); when the drilling fluid passes through the motor assembly (2), the drilling fluid pressure energy is converted into the rotational mechanical energy of the motor assembly (2) and transmitted to the transmission shaft (67) to drive the transmission shaft (67) to rotate, and the inner cam (42) is connected to the transmission shaft (67) through a thread and rotates with the transmission shaft (67). When the inner cam (42) rotates, under the joint action of the first cam groove (422) and the slide groove (412), the slider (44), the pin (45), and the roller (46) are pushed to perform periodic up and down movements as a whole; under the joint action of the pin (45) and the second cam groove (432), the outer cam (43) is pushed to perform periodic circumferential swing, and the second impact block (431) periodically impacts the first impact block (411) to achieve periodic torsional impact; The axial impact assembly (5) is mainly composed of an axial impact housing (51), a first retaining ring (52), a first compression spring (53), a positioning screw (54), an upper cam (55), a lower cam (56) and a flat key (57); the axial impact housing (51) is provided with a first stop (501) and an annular array of threaded holes (502); the upper cam (55) is provided with an annular array of upper cam teeth (551) and a first groove (552); the first compression spring One end of the upper cam (53) abuts against the first abutment (501), and the other end abuts against the upper part of the upper cam (55); the upper cam (55) is circumferentially fixed in the axial impact housing (51) by a positioning screw (54), and can slide axially along the positioning screw (54); the lower cam (56) is provided with a lower cam tooth (561), a first keyway (562) and a second step surface (563); the lower cam (56) is circumferentially fixed to the transmission shaft (67) by a flat key (57), and moves along with the transmission shaft The first retaining ring (52) has an upper end abutting against the lower side of the inner cam (42), and one end abutting against the second step surface (563) of the inner cam (42); when the drilling fluid flows through the motor assembly (2), the drilling fluid liquid pressure energy is converted into rotational mechanical energy and transmitted to the transmission shaft assembly (6) to drive the transmission shaft (67) to rotate, and the lower cam (56) rotates along with the transmission shaft (67). When the lower cam teeth (561) and the upper cam teeth (551) are connected, the lower cam teeth (561) and the upper cam teeth (551) rotate. ) periodically push the upper cam (55) to reciprocate up and down. When the upper cam (55) moves upward, the first compression spring (53) is compressed to convert the rotational mechanical energy of the transmission shaft (67) into elastic potential energy storage of the first compression spring (53); when the upper cam (55) moves downward, under the joint action of the upper cam (55)'s own weight and the first compression spring (53), the upper cam (55) is pushed to accelerate downward to impact the lower cam (56) to achieve periodic reciprocating up and down impact.

2. A composite impact screw according to claim 1, characterized in that: The torsional impact housing (41) is provided with a first impact block (411) and a first slide groove (412); the number of the first impact blocks (411) is 2 to 4; the number of the first slide grooves (412) is the same as that of the first impact blocks (411).

3. A composite impact screw according to claim 1, characterized in that: The inner cam (42) is provided with a first cam groove (422); the first cam groove (422) is provided with a push section and a return section; the number of the push sections and the return sections is consistent with the number of the first impact blocks (411).

4. A composite impact screw according to claim 1, characterized in that: The outer cam (43) is provided with a second cam groove (432); the second cam groove (432) is a discontinuous oblique groove, and the number of the second cam groove (432) is the same as that of the first impact block (411).

5. The composite impact screw according to claim 1, characterized in that: The axial impact shell (51) is provided with an annular array of threaded holes (502), and the number of the annular array of threaded holes (502) is 3 to 6.

6. The composite impact screw according to claim 1, characterized in that: The upper cam (55) is provided with upper cam teeth (551) and first grooves (552), the number of the upper cam teeth (551) is 3 to 6, and the number of the first grooves (552) is consistent with the number of the annular array threaded holes (502); one end of the positioning screw (54) is connected to the annular array threaded holes (502) through a thread, and the other end is connected to the first groove (552), and the upper cam (55) can slide along the axial direction of the positioning screw (54), and the sliding stroke is 10 to 40 mm.

7. The composite impact screw according to claim 1, characterized in that: The lower cam (56) is provided with lower cam teeth (561), a first keyway (562) and a second step surface (563); the shape, size and number of the lower cam teeth (561) are consistent with those of the upper cam teeth (551); the number of the first keyway (562) is 1-3.

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