CN117432324A

CN117432324A - Air down-the-hole hammer

Info

Publication number: CN117432324A
Application number: CN202311658570.5A
Authority: CN
Inventors: 岳永东; 谭春亮; 朱文鉴; 冉灵杰; 渠洪杰; 卢倩; 祝强; 苏兴涛; 冯跃文; 林广利; 卢猛; 宋殿兰
Original assignee: Beijing Institute of Exploration Engineering
Current assignee: Beijing Institute of Exploration Engineering
Priority date: 2023-12-06
Filing date: 2023-12-06
Publication date: 2024-01-23

Abstract

The invention relates to the technical field of geological drilling construction, in particular to an air down-the-hole hammer which can drive a drill bit to rotate unidirectionally by utilizing axial reciprocating motion of a down-the-hole hammer piston. In the drilling process, the drill rod and the drilling tool are not required to rotate while the advantage of high-efficiency impact of the air down-the-hole hammer on crushed rock is maintained, so that the stress condition of the drill rod under the gas drilling working condition can be improved, the service life of the drill rod is prolonged, the application of the air down-the-hole hammer drilling process in directional drilling can be further expanded, and the drilling efficiency of directional drilling, particularly hard rock and strong abrasive stratum is improved. Compared with the prior art, the invention has the advantages of reliable structure, small rotation resistance, large output torque and good practicability.

Description

Air down-the-hole hammer

Technical Field

The invention relates to the technical field of geological drilling construction, in particular to an air down-the-hole hammer.

Background

The air down-the-hole hammer drilling process breaks rock in an impact rotation mode, is beneficial to volume breaking of rock, improves mechanical drilling speed, is particularly suitable for hard rock, gravel layers, broken strata and the like, has the advantages of being suitable for construction in water-deficient areas, green and environment-friendly, capable of protecting beneficial reservoirs and the like, and is one of the best methods for improving drilling construction efficiency and reducing construction cost.

However, when the conventional air down-the-hole hammer drills, the drill rod is required to drive the air down-the-hole hammer to rotate, which has certain limitation in the application process, and the specific expression is as follows: and (1) the stress condition of the drill string is bad. Under the condition of gas drilling, due to lack of lubrication and viscous damping of slurry, the eccentric wear of the drill rod and the well wall is more severe in the rotating process of the drill rod, and the fatigue life of the drill rod can be greatly reduced; (2) is not suitable for directional drilling. If the conventional air down-the-hole hammer drilling is required to realize the adjustment of the borehole track, the drilling tool can only be used for deflecting by adjusting the position of a centralizer or a stabilizer in a drilling tool assembly or adopting a drill bit with an inclined plane, so that higher requirements are put forward on the slewing capability of the drilling machine, the eccentric wear of a drill string is further aggravated, and meanwhile, the accurate control of the drilling track cannot be realized.

In order to improve the stress condition of the drill string, more importantly, the application of the air down-the-hole hammer drilling technology in directional drilling is expanded, and an air down-the-hole hammer with a drill bit capable of rotating automatically is required to be designed. Researchers at home and abroad explore the problems that a turning device is additionally arranged in a down-the-hole hammer body, a drill bit is driven to rotate by utilizing the linear reciprocating motion of a piston, so that the drill bit is prevented from repeatedly impacting the same position to form a groove to damage drill bit teeth, rock breaking is still mainly carried out by impact, the drill bit turns to intermittent motion, but the whole is still in a scheme research stage at present, no practical application exists, and the problems of small output torque, large resistance of the turning device, complex structure, large processing difficulty, poor reliability and the like exist.

Disclosure of Invention

One of the technical problems to be solved by the invention is as follows: the existing scheme has at least one of the problems of small output torque, large resistance of the slewing device, complex structure, large processing difficulty, poor reliability and the like.

(II) technical scheme

In order to solve the above technical problems, the present invention provides an air down-the-hole hammer, comprising: the air down-the-hole hammer includes: the device comprises an upper connector, a shell, a gas distribution valve seat, an inner cylinder, a piston, a spiral sleeve and a transmission sleeve which are arranged in the shell, a lower connector connected with the shell, and a drill bit connected with the lower connector; wherein,

the upper joint is fixedly connected to the upper end of the shell;

the upper end of the air distribution valve seat is used for being elastically connected with a check valve, the check valve is connected with the lower end of the upper joint, and the air distribution valve seat is provided with a plurality of vent holes;

the inner cylinder is fixedly sleeved at the upper end of the air distribution valve seat, a channel is formed between the inner cylinder and the shell, and a rear air hole communicated with the air hole and the channel is formed in the inner cylinder;

the outer wall of the piston is also provided with a piston surface air passage, the inner cylinder is also provided with a front air hole communicated with the piston surface air passage, and the lower end of the air distribution valve seat is arranged in the inner cylinder and the piston in a penetrating way;

the spiral sleeve is sleeved outside the lower end of the piston;

the transmission sleeve is sleeved outside the spiral sleeve and connected with the drill bit, and the transmission sleeve and the spiral sleeve can be combined or separated;

the piston reciprocates up and down along the axial direction of the shell to drive the spiral sleeve to rotate so as to drive the drill bit to rotate unidirectionally.

According to one embodiment of the invention, the air down-the-hole hammer further comprises: the clamping block is provided with a notch, the clamping block is rotationally arranged at the notch, outer teeth are arranged on the outer side of the spiral sleeve, and the clamping block stretches out of the notch to be in contact with or separated from the outer teeth under the action of the clamping block spring, so that the transmission sleeve is combined with or separated from the spiral sleeve.

According to one embodiment of the invention, the inner cylinder is further provided with a strong blowing hole, the strong blowing hole is located between the rear air hole and the front air hole, and the piston moves up and down to enable the strong blowing hole to be communicated with the center hole of the piston.

According to one embodiment of the invention, the piston sequentially comprises a large end, a middle section and a small end from top to bottom, a central hole at the large end is matched with a gas distribution rod of the gas distribution valve seat, and a gas channel on the outer surface of the piston is axially arranged and can be communicated with the large end and the middle section;

the outer surface of the piston is also provided with at least two piston limiting grooves which are axially symmetrical, and the piston limiting grooves are used for being matched with a positioning pin penetrating through the shell.

According to one embodiment of the invention, a spiral key groove is formed in the spiral sleeve, piston spiral keys matched with the spiral key groove are symmetrically formed on the lower end of the small end, and the spiral keys are always kept in the spiral key groove when the piston moves axially.

According to one embodiment of the invention, the air distribution valve seat is in transition fit with the inner cylinder, two ends of the air distribution valve seat are positioned through the lower end of the upper joint and a boss in the inner cylinder, a stepped through hole is formed in the center of the air distribution valve seat along the axial direction, a check valve and a spring connected with the check valve are arranged at the large diameter of the through hole, and an air passage of an air distribution rod is arranged at the small diameter of the through hole.

According to one embodiment of the invention, the outer surface of the transmission sleeve is provided with two grooves for placing balls; the balls are used for reducing friction resistance between the transmission sleeve and the shell in the rotating process of the transmission sleeve.

According to one embodiment of the invention, the air down-the-hole hammer further comprises a retaining ring, wherein the retaining ring is limited by a step arranged in the shell and the upper end face of the lower joint respectively, and the retaining ring clamps the drill bit.

According to one embodiment of the invention, the air down-the-hole hammer further comprises a bearing sleeve and a bearing, wherein the outer diameter of the upper end of the bearing is in interference fit with the lower joint, the outer diameter of the lower end of the bearing is in clearance fit with the lower joint, the inner diameter of the lower end of the bearing is in interference fit with the bearing sleeve, and the outer diameter of the upper end of the bearing is in clearance fit with the bearing sleeve.

According to one embodiment of the invention, the end surfaces of the spiral sleeve and the transmission sleeve are provided with gaskets.

The invention has the beneficial effects that: the drill bit can be driven to rotate unidirectionally by utilizing the axial reciprocating motion of the down-the-hole hammer piston. In the drilling process, the drill rod and the drilling tool are not required to rotate while the advantage of high-efficiency impact of the air down-the-hole hammer on crushed rock is maintained, so that the stress condition of the drill rod under the gas drilling working condition can be improved, the service life of the drill rod is prolonged, the application of the air down-the-hole hammer drilling process in directional drilling can be further expanded, and the drilling efficiency of directional drilling, particularly hard rock and strong abrasive stratum is improved. Compared with the prior art, the invention has the advantages of reliable structure, small rotation resistance, large output torque and good practicability.

Drawings

The advantages of the foregoing and/or additional aspects of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic diagram of an air down-the-hole hammer of the present invention as a whole that may be used in directional drilling.

Fig. 2 is a schematic cross-sectional view of A-A of the air down-the-hole hammer of fig. 1.

Fig. 3 is a schematic cross-sectional view of a B-B section of the air down-the-hole hammer of fig. 1.

Fig. 4 is a schematic view of the inner cylinder structure of the air down-the-hole hammer of the present invention.

Fig. 5 is a schematic diagram of a piston structure of the air down-the-hole hammer of the present invention.

Fig. 6 is a schematic diagram of a spiral sleeve structure of the air down-the-hole hammer of the present invention.

Fig. 7 is a schematic diagram of a driving sleeve structure of the air down-the-hole hammer of the present invention.

Fig. 8 is a schematic diagram of a piston return start stage of the air down-the-hole hammer of the present invention.

Fig. 9 is a schematic diagram of the piston stroke initiation stage of the air down-the-hole hammer of the present invention.

Fig. 10 is a schematic diagram of the forced-air deslagging stage of the air down-the-hole hammer of the present invention.

The reference numerals are as follows:

1-upper joint, 2-outer tube, 3-inner cylinder, 4-gas distribution valve seat, 5-check valve, 6-spring, 7-piston, 8-locating pin, 9-spiral sleeve, 10-upper copper sleeve, 11-transmission sleeve, 12-ball, 13-ring, 14-lower copper sleeve, 15-lower joint, 16-thrust ball bearing, 17-bearing sleeve, 18-drill bit, 19-fixture block, 20-fixture block spring piece, 21-fixture block pin, I-back air chamber, II-front air chamber,

301-a rear air hole, 302-a strong blowing hole, 303-a front air hole, 701-a piston surface air passage, 702-a piston limit groove and 703-a piston spiral key; 901-spiral grooves, 902-outer teeth, 903-spiral sleeve air holes, 1101-openings, 1102-spline grooves and 1103-grooves.

Detailed Description

In order that the above-recited objects, features and advantages of the present invention will be more clearly understood, a more particular description of the invention will be rendered by reference to the appended drawings and appended detailed description. It should be noted that, in the case of no conflict, the embodiments of the present application and the features in the embodiments may be combined with each other.

As shown in fig. 1 to 10, the present invention provides an air down-the-hole hammer comprising: the air down-the-hole hammer includes: the device comprises an upper joint 1, a shell 2, a distributing valve seat 4, an inner cylinder 3, a piston 7, a spiral sleeve 9 and a transmission sleeve 11 which are arranged in the shell 2, a lower joint 15 connected with the shell 2, and a drill bit 18 connected with the lower joint 15; wherein,

the upper joint 1 is fixedly connected to the upper end of the shell 2;

the upper end of the air distributing valve seat 4 is used for being elastically connected with a check valve 5, the check valve 5 is connected with the lower end of the upper joint 1, and the air distributing valve seat 4 is provided with a plurality of vent holes;

the inner cylinder 3 is fixedly sleeved at the upper end of the distributing valve seat 4, a channel is formed between the inner cylinder 3 and the shell 2, and a rear air hole 301 communicated with the air hole and the channel is formed in the inner cylinder 3;

the outer wall of the piston 7 is also provided with a piston surface air passage 701, the inner cylinder 3 is also provided with a front air hole 303 communicated with the piston surface air passage 701, and the lower end of the distributing valve seat 4 is penetrated in the inner cylinder 3 and the piston 7;

the spiral sleeve 9 is sleeved outside the lower end of the piston 7;

the transmission sleeve 11 is sleeved outside the spiral sleeve 9 and is connected with the drill bit 18, and the transmission sleeve 11 and the spiral sleeve 9 can be combined or separated;

wherein, the piston 7 reciprocates up and down along the axial direction of the shell 2 to drive the spiral sleeve 9 to rotate so as to drive the drill bit 18 to rotate unidirectionally.

In the invention, the center of the upper joint 1 is a through hole, the upper end of the upper joint 1 is connected with an upper drill rod, and the lower end of the upper joint 1 is connected with the shell 2 through threads. The high-pressure gas enters the air down-the-hole hammer through the central hole of the upper joint 1.

The two ends of the shell 2 are internally threaded holes, the upper joint 1 and the lower joint 15 are respectively connected, a plurality of sections of unthreaded holes with different lengths and different inner diameters are formed in the shell 2 along the axial direction of the shell, and the limiting or the effect of producing different air paths by matching with the inner cylinder 3, the piston 7 and the like is achieved.

The inner cylinder 3 is arranged in the shell 2 and is a cylindrical cylinder sleeve with stepped inner and outer parts, steps at the upper end and the lower end of the inner cylinder 3 are in transition fit with the shell 2, an annular channel is formed between the middle section and the shell 2, the upper end face is in contact with the lower end face of the upper joint 1, and the lower end face is positioned through the steps arranged in the shell 2.

4 notches 1101 are uniformly distributed on the upper side of the air distribution valve seat 4 along the circumference, and high-pressure air is guided to enter an annular channel between the inner cylinder 3 and the outer shell 2 through the rear air holes 301 of the inner cylinder 3 after passing through the notches 1101 of the air distribution valve seat 4 through the cooperation of the air distribution valve seat 4 and the inner cylinder 3.

According to one embodiment of the invention, the air down-the-hole hammer further comprises: the clamping block 19 and the clamping block 19 spring 6 are arranged on the transmission sleeve 11, a notch 1101 is formed in the transmission sleeve 11 in a rotating mode, the clamping block 19 is arranged at the position of the notch 1101, outer teeth 902 are arranged on the outer side of the spiral sleeve 9, the clamping block 19 stretches out of the notch 1101 to be in contact with or separate from the outer teeth 902 under the action of the clamping block 19 spring 6, and the transmission sleeve 11 is combined with or separated from the spiral sleeve 9.

The transmission sleeve 11 is arranged between the outer shell 2 and the spiral sleeve 9. The upper end of the transmission sleeve 11 is uniformly provided with a set number of rectangular openings 1101 along the circumference, the lower end of the spiral sleeve 9 is inserted into the transmission sleeve 11, and the outer teeth 902 of the spiral sleeve 9 are axially aligned with the openings 1101.

The clamping block 19 is arranged in a notch 1101 at the upper end of the transmission sleeve 11 through a clamping block pin shaft 21, one end of the clamping block spring piece 20 is connected with the clamping block 19, and the other end is a free end. The latch 19 is biased inward in a free state by the elastic force of the latch spring 20, and protrudes out of the notch 1101 to contact with the outer teeth 902 of the screw sleeve 9.

The spiral sleeve 9, the transmission sleeve 11, the clamping block 19, the clamping block pin shaft 21 and the clamping block spring piece 20 form a clutch transmission mechanism, and the clutch transmission mechanism is a key mechanism for driving the drill bit 18 to rotate unidirectionally by utilizing the reciprocating linear motion of the piston 7. Taking the structure shown in fig. 3 as an example, the working principle is that when the piston 7 drives the screw sleeve 9 to rotate clockwise, the clamping block 19 props against the outer teeth 902 of the screw sleeve 9, and the screw sleeve 9 drives the transmission sleeve 11 to rotate, so that the drill bit 18 is driven to rotate clockwise; when the piston 7 drives the screw sleeve 9 to rotate anticlockwise, the outer teeth 902 of the screw sleeve 9 push the clamping block 19 to move upwards, the transmission sleeve 11 does not rotate, and the drill bit 18 does not rotate. The clutch transmission mechanism can allow the combination and separation state of the clamping block 19 and the outer side teeth 902 of the spiral sleeve 9 to be switched reliably with high response frequency so as to meet the reciprocating movement frequency of the down-the-hole hammer piston 7 of about 20 Hz.

The number of the outer teeth 902 of the screw sleeve 9 depends on the rotation angle of the screw sleeve 9 driven by the piston 7, and the resolution, that is, the angle obtained by dividing 360 degrees by the number of the outer teeth 902, is slightly smaller than the rotation angle of the screw sleeve 9 driven by the piston 7.

The number of the teeth 902 on the outer side of the spiral sleeve 9 can be 2 times that of the notches 1101, so that all the tooth blocks are engaged with the teeth 902 on the outer side of the spiral sleeve 9 in the process that the spiral sleeve 9 drives the transmission sleeve 11 to rotate each time, the structural strength is improved, and large torque is transmitted.

The transmission sleeve 11 is in clearance fit with the shell 2 and the spiral sleeve 9, so that friction resistance in the rotating process is reduced. The lower end of the transmission sleeve 11 is provided with a spline groove 1102 which is matched with a bit shank spline of the drill bit 18 to drive the drill bit 18 to rotate.

According to an embodiment of the present invention, the inner cylinder 3 is further provided with a strong blowing hole 302, the strong blowing hole 302 is located between the rear air hole 301 and the front air hole 303, and the piston 7 moves up and down to enable the strong blowing hole 302 to be communicated with the central hole of the piston 7.

The inner cylinder 3 is provided with three exhaust holes from left to right, namely a rear air hole 301, a strong blowing hole 302 and a front air hole 303, and annular channels between the rear air hole 301 and the front air hole 303 and the inner cylinder 3 and the shell 2 form a high-pressure air inlet passage for driving the piston 7 to impact in a reciprocating manner.

According to one embodiment of the invention, the piston 7 sequentially comprises a large end, a middle section and a small end from top to bottom, a central hole at the large end is matched with a gas distribution rod of the gas distribution valve seat 4, and a gas channel on the outer surface of the piston 7 is axially arranged and can be communicated with the large end and the middle section;

the outer surface of the piston 7 is also provided with at least two axially symmetrical piston limit grooves 702, and the piston limit grooves 702 are used for being matched with positioning pins 8 penetrating through the shell 2.

The piston 7 is of a stepped shaft type structure with a central through hole and consists of a large end, a middle section and a small end. The annular space between the piston 7, the inner cylinder 3 and the distributing valve seat 4 forms a rear air chamber I, and the annular space between the piston 7, the shell 2, the spiral sleeve 9 and the transmission sleeve 11 forms a front air chamber II. The large end of the piston 7 is matched with the inner cylinder 3, the middle section is matched with the shell 2, the small end is matched with the spiral sleeve 9, the central hole of the large end is matched with the air distribution rod of the air distribution valve seat 4, the air passage which is used for communicating the large end and the middle section of the piston 7 is axially arranged on the outer surface of the piston 7, two limiting grooves matched with the positioning pin 8 are axially symmetrically arranged on the outer surface of the middle section, and two spiral keys are symmetrically arranged on the lower end of the small end. The piston 7 can axially reciprocate, and when the piston 7 moves to different positions, the air inlet and outlet channels of the front and rear air chambers can be alternately opened and closed.

The positioning pin 8 is installed through the opening of the shell 2 and is matched with the groove on the piston 7, so as to limit the rotation of the piston 7.

According to one embodiment of the invention, a spiral key groove is arranged inside the spiral sleeve 9, a piston spiral key 703 matched with the spiral key groove is symmetrically arranged on the lower end of the small end, and the spiral key is always kept in the spiral key groove when the piston 7 moves axially.

The spiral sleeve 9 is internally provided with a spiral key groove which is matched with a spiral key at the small end of the piston 7, and the spiral key is always kept in the spiral groove 901 in the axial movement process of the piston 7. The spiral key and the spiral groove 901 form a spiral kinematic pair, so that the spiral sleeve 9 is driven to rotate by the linear motion of the piston 7. The outside of the spiral sleeve 9 is provided with a plurality of outside teeth 902 with set angles and a plurality of outside teeth, and the spiral sleeve 9 is radially provided with a spiral sleeve air hole 903 serving as an exhaust channel of the front air chamber.

The upper copper sleeve 10 is located between the screw sleeve 9 and the outer shell 2, and is used for reducing the friction resistance of the screw sleeve 9 in rotation and limiting the axial movement of the screw sleeve 9. The upper copper sleeve 10 is uniformly distributed with air holes along the axial circumference, and the overflow area of the upper copper sleeve is matched with the area of the spiral sleeve air holes 903 as an exhaust passage of the front air chamber.

According to one embodiment of the invention, the distributing valve seat 4 is in transition fit with the inner cylinder 3, two ends of the distributing valve seat 4 are positioned through the lower end of the upper joint 1 and a boss inside the inner cylinder 3, a stepped through hole is axially formed in the center of the distributing valve seat 4, a large diameter part of the through hole is used for installing a check valve 5 and a spring 6 connected with the check valve 5, and a small diameter part of the through hole is an air passage of a distributing rod.

The lower side of the air distribution valve seat 4 is an air distribution rod, a stepped through hole is axially formed in the center of the air distribution valve seat 4, the upper side large-diameter through hole is used for installing a check valve 5 and a spring 6, and the lower side small-diameter through hole is an air passage of the air distribution rod.

The check valve 5 and the spring 6 are arranged in a large-diameter through hole at the upper end of the air distribution valve seat 4, and the upper end part of the check valve 5 is matched with the through hole of the upper joint 1. The function of the non-return valve 5 is to allow only high pressure gas to enter the down-the-hole hammer via the central passage of the upper sub 1, preventing reverse flow of gas.

According to one embodiment of the present invention, the outer surface of the driving sleeve 11 is provided with two grooves 1103 for placing the balls 12; the balls 12 serve to reduce frictional resistance with the housing 2 during rotation of the driving sleeve 11.

The balls 12 serve to reduce frictional resistance with the housing 2 during rotation of the transmission sleeve 11, while limiting axial movement of the transmission sleeve 11. When the air down-the-hole hammer is assembled, the balls 12 are sequentially put into corresponding holes on the shell 2, uniformly distributed with grooves of the transmission sleeve 11, and then the holes on the shell 2 are plugged by plugs and the like.

According to one embodiment of the present invention, the air down-the-hole hammer further comprises a retaining ring 13, wherein the retaining ring 13 is limited by a step arranged in the housing 2 and the upper end face of the lower joint 15, and the retaining ring 13 is used for clamping the drill bit 18.

The retaining ring 13 is a pair of semicircular rings, the drill bit 18 is prevented from falling by clamping the small diameter part of the middle section of the drill bit shank of the drill bit 18, and the upper end and the lower end of the retaining ring are limited by a step arranged in the shell 2 and the upper end face of the lower joint 15 respectively. A gap is left between the transmission sleeve 11 and the retaining ring 13 in the axial direction.

The lower copper sleeves 14 are arranged between the lower joint 15 and the shank of the drill bit 18 in pairs, and the lower copper sleeves 14 play roles in reducing rotational friction resistance and guaranteeing the coaxiality of the shank of the drill bit 18.

According to one embodiment of the invention, the air down-the-hole hammer further comprises a bearing sleeve 17 and a bearing 16, wherein the outer diameter of the upper end of the bearing 16 is in interference fit with the lower joint 15, the outer diameter of the lower end of the bearing 16 is in clearance fit with the lower joint 15, the inner diameter of the lower end of the bearing 16 is in interference fit with the bearing sleeve 17, and the outer diameter of the upper end of the bearing 16 is in clearance fit with the bearing sleeve 17.

The lower joint 15 is of a stepped through hole structure and is connected with the shell 2 through threads.

The thrust ball bearing 16 is installed in a lower end hole of the lower joint 15, the outer diameter of the upper end of the thrust ball bearing is in interference fit with the lower joint 15, the outer diameter of the lower end of the thrust ball bearing is in clearance fit with the lower joint 15, the inner diameter of the lower end of the thrust ball bearing is in interference fit with the bearing sleeve 17, and the outer diameter of the upper end of the thrust ball bearing is in clearance fit with the bearing sleeve 17.

The cross section of the bearing sleeve 17 is of an inverted L-shaped structure, and the lower end face of the bearing sleeve contacts with the upper end face of the head of the drill bit 18. The bearing sleeve 17 is in clearance fit with the shank of the lower joint 15 and the drill bit 18.

The weight of the drill bit and the weight of the drill string are transferred to the drill bit 18 through the housing 2, the lower joint 15, the thrust ball bearing 16, the bearing housing 17.

The bit 18 includes a head portion and a shank portion, a central through bore, with the shank portion being splined to mate with a spline groove 1102 in the drive sleeve. The head of the drill bit 18 is spaced from the end face of the lower end of the lower joint 15. To reduce frictional resistance of the contact face as the bit 18 rotates.

The upper copper sleeve 10, the lower copper sleeve 14, the bearing sleeve 17 and the like can be axially limited by adopting hole check rings and the like.

According to one embodiment of the invention, the end surfaces of the screw sleeve 9 and the driving sleeve 11 are provided with gaskets.

Wear-resistant and lubrication gaskets can be added to the end surfaces of the spiral sleeve 9 and the transmission sleeve 11 so as to reduce friction resistance when the spiral sleeve 9 rotates.

The pitch of the helical groove 901 of the helical sleeve 9 and the effective movement travel of the piston 7 determine the angle at which each movement of the piston 7 drives the drill bit 18 to rotate.

The direction of rotation of the piston screw key 703, the screw groove 901 of the screw sleeve 9, and the direction of inclination of the teeth 902 and the latch 19 on the outside of the screw sleeve 9 depend on whether the drill bit 18 is driven to rotate and the direction of rotation of the drill bit 18 during the stroke or return stroke of the piston 7. Taking the structure shown in fig. 1-7 as an example, the drill bit 18 is driven to rotate clockwise (from left to right) when the piston 7 is returned.

Taking the structure shown in fig. 8-10 as an example, the specific working principle of the air down-the-hole hammer is as follows:

as shown in fig. 8, in the piston return stage, high-pressure air pushes the check valve 5 open through the center hole of the upper joint 1, and enters the piston surface air passage 701 of the piston through the air distribution valve seat 4, the rear air hole 301 of the inner cylinder 3, the annular passages of the inner cylinder 3 and the housing 2, and the inner cylinder front air hole 303. The piston 7 seals the air inlet channel of the rear air chamber I, the small end of the piston plugs the spiral sleeve air hole 903 to seal the front air chamber exhaust channel, high-pressure air enters the front air chamber II of the down-the-hole hammer, the gas of the rear air chamber I is discharged through the central through hole of the piston 7, and the piston 7 accelerates the return stroke under the action of pressure difference; when the piston 7 moves to a certain degree, the air inlet channel of the front air chamber II and the air outlet channel of the rear air chamber I are sequentially closed, the pressure of the front air chamber II is continuously reduced, and the air in the rear air chamber I is compressed to prevent the piston 7 from continuously ascending, so that the piston 7 is decelerated and returned; as the piston 7 continues to decelerate and return, the spiral sleeve air hole 903 is opened, the exhaust passage of the front air chamber ii is opened, the exhaust gas is discharged to the bottom of the hole through the center hole of the piston 7, the intake passage of the rear air chamber i is opened, the rear air chamber starts to intake air, and the piston further decelerates and returns until moving to the top dead center. In the piston return stage, the piston 7 drives the spiral sleeve 9 to rotate clockwise, and the spiral sleeve 9 drives the transmission sleeve 11 to rotate clockwise through the clamping block 19, so that the drill bit 18 is driven to rotate clockwise by a certain angle.

As shown in fig. 9, the piston stroke stage is the reverse process of the piston return stage, and the high-pressure air distribution process is not described again. In the piston stroke stage, the piston 7 drives the spiral sleeve 9 to rotate anticlockwise, the spiral sleeve pushes the clamping block 19 to ascend, the transmission sleeve 11 does not rotate, and the drill bit 18 does not rotate.

As shown in fig. 10, when the high-pressure air is required to be blown strongly to the bottom of the hole for deslagging, the down-the-hole hammer is lifted away from the bottom of the hole for a small distance, the drill bit 18 is separated from contact with the bottom of the hole, the drill bit 18 slides downwards due to self weight, the piston 7 slides downwards along with the drill bit, the piston 7 seals the air inlet channel of the front air chamber II, the strong blowing hole 302 of the inner cylinder 3 is opened after the piston 7 slides downwards, the high-pressure air directly enters the bottom of the hole through the central hole after entering the rear air chamber I, the piston 7 is not driven to reciprocate, and all high-pressure air is directly used for blowing strongly to deslagg, so that the purpose of cleaning the bottom of the hole is realized. To resume the impact, the drill is simply fed to the drill bit 18 against the rock.

In summary, the drill bit can be driven to rotate unidirectionally by the axial reciprocating motion of the piston of the down-the-hole hammer. In the drilling process, the drill rod and the drilling tool are not required to rotate while the advantage of high-efficiency impact of the air down-the-hole hammer on crushed rock is maintained, so that the stress condition of the drill rod under the gas drilling working condition can be improved, the service life of the drill rod is prolonged, the application of the air down-the-hole hammer drilling process in directional drilling can be further expanded, and the drilling efficiency of directional drilling, particularly hard rock and strong abrasive stratum is improved. Compared with the prior art, the invention has the advantages of reliable structure, small rotation resistance, large output torque and good practicability.

In the description of the present invention, it should be noted that the azimuth or positional relationship indicated by the terms "upper", "lower", etc. are based on the azimuth or positional relationship shown in the drawings, and are merely for convenience of describing the present invention and simplifying the description, and are not indicative or implying that the apparatus or element in question must have a specific azimuth, be constructed and operated in a specific azimuth, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; the communication may be direct or indirect through an intermediate medium, or may be internal to two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art. Furthermore, in the description of the present invention, unless otherwise indicated, the meaning of "a plurality" is two or more.

The foregoing description of the preferred embodiments of the invention is not intended to limit the invention to the precise form disclosed, and any such modifications, equivalents, and alternatives falling within the spirit and scope of the invention are intended to be included within the scope of the invention.

Claims

1. An air down-the-hole hammer, characterized in that the air down-the-hole hammer comprises: the device comprises an upper connector, a shell, a gas distribution valve seat, an inner cylinder, a piston, a spiral sleeve and a transmission sleeve which are arranged in the shell, a lower connector connected with the shell, and a drill bit connected with the lower connector; wherein,

the upper joint is fixedly connected to the upper end of the shell;

the spiral sleeve is sleeved outside the lower end of the piston;

2. An air down-the-hole hammer as set forth in claim 1, wherein: the air down-the-hole hammer further comprises: the clamping block is provided with a notch, the clamping block is rotationally arranged at the notch, outer teeth are arranged on the outer side of the spiral sleeve, and the clamping block stretches out of the notch to be in contact with or separated from the outer teeth under the action of the clamping block spring, so that the transmission sleeve is combined with or separated from the spiral sleeve.

3. An air down-the-hole hammer as set forth in claim 1, wherein: the inner cylinder is also provided with a strong blowing hole, the strong blowing hole is positioned between the rear air hole and the front air hole, and the piston moves up and down to enable the strong blowing hole to be communicated with the central hole of the piston.

4. An air down-the-hole hammer as set forth in claim 1, wherein: the piston sequentially comprises a large end, a middle section and a small end from top to bottom, a central hole at the large end is matched with a gas distribution rod of the gas distribution valve seat, and a gas channel on the outer surface of the piston is axially arranged and can be communicated with the large end and the middle section;

5. An air down-the-hole hammer as set forth in claim 4, wherein: the inside spiral keyway that is provided with of spiral shell, the symmetry be provided with on the lower extreme of tip with the piston spiral key that the spiral keyway matches, when the piston axial displacement, the spiral key remains in the spiral keyway all the time.

6. An air down-the-hole hammer as set forth in claim 1, wherein: the air distribution valve seat is in transition fit with the inner cylinder, two ends of the air distribution valve seat are positioned through the lower end of the upper joint and a boss inside the inner cylinder, a stepped through hole is formed in the center of the air distribution valve seat along the axial direction, a check valve and a spring connected with the check valve are arranged at the large diameter of the through hole, and an air passage of an air distribution rod is arranged at the small diameter of the through hole.

7. An air down-the-hole hammer as set forth in claim 1, wherein: the outer surface of the transmission sleeve is provided with two grooves for placing balls; the balls are used for reducing friction resistance between the transmission sleeve and the shell in the rotating process of the transmission sleeve.

8. An air down-the-hole hammer as set forth in claim 1, wherein: the air down-the-hole hammer further comprises a retaining ring, wherein the retaining ring is limited through a step arranged in the shell and the end face of the upper end of the lower connector respectively, and the retaining ring clamps the drill bit.

9. An air down-the-hole hammer as set forth in claim 1, wherein: the air down-the-hole hammer further comprises a bearing sleeve and a bearing, wherein the outer diameter of the upper end of the bearing is in interference fit with the lower joint, the outer diameter of the lower end of the bearing is in clearance fit with the lower joint, the inner diameter of the lower end of the bearing is in interference fit with the bearing sleeve, and the outer diameter of the upper end of the bearing is in clearance fit with the bearing sleeve.

10. An air down-the-hole hammer as set forth in claim 1, wherein: and gaskets are arranged on the end surfaces of the spiral sleeve and the transmission sleeve.