Down-hole hammer drilling tool gas circuit structure

Abstract

A central vent hole and a piston outer wall are formed in a piston, the lower end portion of a gas transmission needle is connected into the central vent hole in a matched and sliding mode, a gas transmission hole is formed in the lower end portion of the gas transmission needle, and a return stroke air inlet hole is formed in the upper portion of the piston. The upper end of the return air inlet is communicated with the central vent hole, the lower end of the return air inlet penetrates through the outer wall of the piston, a stroke air inlet is formed in the upper portion of the piston, the axis of the stroke air inlet and the axis of the central vent hole form an acute angle, and the lower end of the stroke air inlet is communicated with the central vent hole. The upper end of the stroke air inlet penetrates through the outer wall of the piston; a sealing sleeve is arranged in the sleeve in a matched mode, and the inserting end of the piston can be connected into the upper portion of the sealing sleeve in a matched and sliding mode. The gas circuit structure of the down-the-hole hammer drilling tool is favorable for improving the durability of the down-the-hole hammer drilling tool and is favorable for enabling the piston to move back and forth flexibly.

Description

TECHNICAL FIELD

[0001] The utility model relates to a down -the -hole impactor drilling tool field, concretely relates to a down -the -hole impactor drilling tool gas circuit structure. BACKGROUND

[0002] At present, the down -the -hole impactor drilling tool is a kind of engineering pneumatic mechanical drill that utilizes compressed air as power to push piston to impact drill bit to implement stone breaking and hole forming, in addition, the compressed air input to the down -the -hole impactor drilling tool is sprayed from the lower end of the drill bit of the down -the -hole impactor drilling tool to play the role of slag blowing, in the piston return movement process, return air cavity needs to be disconnected with the jet hole of drill bit, otherwise compressed air will directly flow through the jet hole of drill bit and lead to piston unable to return, such as " the excavating down -the -hole impactor with reverse flow structure " of Chinese utility model patent publication No. CN221856616U and " the edge locking structure applied to down -the -hole drill bit " of CN215256043U, piston and drill bit are connected by " rubber pin " gas circuit, when drill bit and piston are connected by rubber pin, the compressed air of return air cavity in the lower side of piston will not enter the jet hole of drill bit, but due to piston relative rubber pin axial (up and down) reciprocating movement, rubber pin is frequently inserted into the lower end exhaust hole of piston, since drill bit also moves up and down, rubber pin moves along with drill bit, so rubber pin and the exhaust hole in the lower end of piston cannot guarantee better coaxiality, although rubber pin has certain elasticity, but it is easy to lead to the upper end of rubber pin rapid wear or rupture in the process of mutual insertion, so that the down -the -hole impactor drilling tool has poor durability, so it is necessary to improve the gas circuit structure of down -the -hole impactor drilling tool. SUMMARY

[0003] The utility model aims at overcoming the insufficient prior art, provide a down -the -hole impactor drilling tool gas circuit structure, it is favorable to improve the durability of down -the -hole impactor drilling tool.

[0004] The utility model relates to a down -the -hole impactor drilling tool field, concretely relates to a down -the -hole impactor drilling tool gas circuit structure.

[0005] The utility model discloses a pneumatic path structure of down-the-hole hammer drill, including gas delivery needle, drill bit and sleeve, the gas delivery needle sets up in the upper portion of sleeve, the upper portion of drill bit is located in the lower end portion of sleeve and slides, be equipped with the piston in the sleeve, wherein, the piston forms the central air hole and the piston outer wall for the inner wall of sleeve of abutting connection, the lower end portion of gas delivery needle is adapted to slide connection in the upper portion of central air hole, the lower end portion of gas delivery needle forms the gas hole of circumferential distribution arrangement, the upper portion of piston forms the return admission hole, the axis of return admission hole and the axis of central air hole form acute angle, the upper end of return admission hole communicates central air hole, the lower end of return admission hole penetrates the piston outer wall, the upper portion of piston forms the admission hole of stroke, the axis of admission hole of stroke and the axis of central air hole form acute angle, the lower end of admission hole of stroke communicates central air hole, the upper end of admission hole of stroke penetrates the piston outer wall, return admission hole and admission hole of stroke circumferential dislocation arrangement, the inner end of return admission hole is located the inner end of admission hole of stroke above, the sleeve is equipped with the sealing sleeve in adaptation, the lower end of piston forms the spigot end, the spigot end can be adapted to slide connection in the upper portion of sealing sleeve, the drill bit forms drill bit gas jet hole, the upper end of drill bit gas jet hole is in line with the lower end of central air hole, the piston outer wall and the upper end between sealing sleeve form return gas cavity, the piston outer wall and the upper portion between gas delivery needle form the admission cavity of stroke, the piston has upper position and lower position relative to the sleeve, in the upper position, the gas hole is connected through the admission hole of stroke, and the spigot end is located the upper portion of sealing sleeve, in the lower position, the gas hole is connected through return admission hole, and the admission cavity of stroke is connected through the admission hole of stroke.

[0006] Preferably, the upper end of the drill bit is located in the lower portion of the sealing sleeve, a sealing ring is arranged between the drill bit and the inner wall of the sleeve, and the sealing sleeve is connected to the upper side of the sealing ring.

[0007] Preferably, a sealing ring is arranged between the sealing sleeve and the inner wall of the sleeve.

[0008] Preferably, the upper end of the sleeve is provided with a top joint, an air inlet hole is formed in the upper part of the top joint, an air inlet cavity is formed in the lower part of the top joint, the lower end of the air inlet hole communicates with the top of the air inlet cavity, a one-way valve assembly is arranged in the top joint, the one-way valve assembly comprises a valve seat and a valve core for closing the lower end of the air inlet hole, the lower part of the valve core is slidingly connected in the valve seat, the valve seat is provided with valve seat air holes arranged in a circle, the valve seat air holes are arranged gradually close to the axis of the valve seat from top to bottom, and the air inlet cavity communicates with the upper end of the air feeding needle through the valve seat air holes.

[0009] Preferably, a labyrinth sealing groove is formed on the outer wall of the piston.

[0010] Compared with the prior art, the utility model has the beneficial effects that: the sealing sleeve is arranged in the sleeve, the lower end of the piston is formed with a plug-in end, the plug-in end is slidingly connected in the upper part of the sealing sleeve, the drill bit is formed with a drill bit air jet hole, the upper end of the drill bit air jet hole is aligned with the lower end of the central air hole, so that the glue pin structure is eliminated, and the sealing sleeve is positioned in the radial direction through the sleeve, thereby improving the durability of the down-the-hole hammer drill. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 It is a sectional view of the down-the-hole hammer drill with the air path structure of the utility model.

[0012] Figure 2 It is a sectional view of the down-the-hole hammer drill with the air path structure of the utility model. Figure 1

[0013] Figure 3 It is a sectional view of the down-the-hole hammer drill with the air path structure of the utility model. Figure 1

[0014] Figure 4 It is a sectional view of the down-the-hole hammer drill with the air path structure of the utility model.

[0015] Figure 5 It is a sectional view of the down-the-hole hammer drill with the air path structure of the utility model.

[0016] Figure 6 It is a sectional view of the down-the-hole hammer drill with the air path structure of the utility model. ​​

[0017] Figure 7 It is a schematic diagram of the three-dimensional structure of the valve seat of the utility model.

[0018] Label explanation: top joint 1; air inlet cavity 10; air inlet hole 101; one-way valve assembly 2; valve core 21; valve seat 22; valve seat air hole 2201; gas delivery needle 3; gas delivery hole 301; piston 4; piston outer wall 40; return air inlet hole 401; return air inlet groove 4010; stroke air inlet hole 402; stroke air inlet groove 4020; labyrinth seal groove 403; central air hole 400; plug end 41; sealing sleeve 5; drill bit 6; drill bit air jet hole 601; sleeve 7; cylinder inner wall part 701; return inner wall part 702; stroke air chamber 710; return air chamber 720; sealing ring 8; sealing ring 9. DETAILED DESCRIPTION

[0019] The utility model will be further described below in combination with the drawings.

[0020] The gas path structure of the down-the-hole hammer drilling tool of the utility model, as shown in Figure 1 and Figure 2 , comprises a gas delivery needle 3, a drill bit 6 and a sleeve 7, the gas delivery needle 3 is arranged in the upper part of the sleeve 7, the upper part of the drill bit 6 is arranged in the lower end part of the sleeve 7 in a sliding manner (along the axis direction of the sleeve 7), and it should be noted that Figure 1 and Figure 3 only the upper part of the drill bit 6 is drawn, and the structure of the drill bit 6 can refer to the "lock edge structure applied to a down-the-hole drill bit" of the Chinese utility model patent with the publication number CN215256043U. As shown in Figure 1 , the sleeve 7 is provided with a piston 4, as shown in Figure 1 and Figure 6 , the piston 4 is formed with a central air hole 400 and a piston outer wall 40 used for abutting against the inner wall of the sleeve 7, the central air hole 400 penetrates the piston 4 along the central axis of the piston 4, as shown in Figure 5 , the sleeve 7 is formed with a cylinder inner wall part 701, as shown in Figure 4 , actually, the piston outer wall 40 is adaptively connected to the cylinder inner wall part 701 in a sliding manner to realize the function of the cylinder. As shown in Figure 1 , the lower end part of the gas delivery needle 3 is adaptively connected to the upper part of the central air hole 400 in a sliding manner, the lower end part of the gas delivery needle 3 is formed with gas delivery holes 301 arranged in a circumferential direction, that is to say, the gas delivery holes 301 are arranged in a circumferential direction around the central axis of the gas delivery needle 3. As shown in Figure 1 and Figure 6As shown in FIG. 1, the upper portion of the piston 4 is formed with a return intake hole 401, the axis of the return intake hole 401 forms an acute angle (for example, 45°) with the axis of the central vent hole 400, the upper end of the return intake hole 401 communicates with the central vent hole 400, and the lower end of the return intake hole 401 penetrates the outer wall 40 of the piston, so that the central vent hole 400 communicates with the outside of the piston 4 through the return intake hole 401, and the return intake hole 401 is arranged to extend obliquely downward from inside to outside. Figure 1 As shown in FIG. 1, the upper portion of the piston 4 is formed with a return intake hole 401, the axis of the return intake hole 401 forms an acute angle (for example, 45°) with the axis of the central vent hole 400, the upper end of the return intake hole 401 communicates with the central vent hole 400, and the lower end of the return intake hole 401 penetrates the outer wall 40 of the piston, so that the central vent hole 400 communicates with the outside of the piston 4 through the return intake hole 401, and the return intake hole 401 is arranged to extend obliquely downward from inside to outside. Figure 6 As shown in FIG. 1, the upper portion of the piston 4 is formed with a return intake hole 401, the axis of the return intake hole 401 forms an acute angle (for example, 45°) with the axis of the central vent hole 400, the upper end of the return intake hole 401 communicates with the central vent hole 400, and the lower end of the return intake hole 401 penetrates the outer wall 40 of the piston, so that the central vent hole 400 communicates with the outside of the piston 4 through the return intake hole 401, and the return intake hole 401 is arranged to extend obliquely downward from inside to outside. Figure 4 As shown in FIG. 1, the upper portion of the piston 4 is formed with a return intake hole 401, the axis of the return intake hole 401 forms an acute angle (for example, 45°) with the axis of the central vent hole 400, the upper end of the return intake hole 401 communicates with the central vent hole 400, and the lower end of the return intake hole 401 penetrates the outer wall 40 of the piston, so that the central vent hole 400 communicates with the outside of the piston 4 through the return intake hole 401, and the return intake hole 401 is arranged to extend obliquely downward from inside to outside. Figure 1 As shown in FIG. 1, the upper portion of the piston 4 is formed with a return intake hole 401, the axis of the return intake hole 401 forms an acute angle (for example, 45°) with the axis of the central vent hole 400, the upper end of the return intake hole 401 communicates with the central vent hole 400, and the lower end of the return intake hole 401 penetrates the outer wall 40 of the piston, so that the central vent hole 400 communicates with the outside of the piston 4 through the return intake hole 401, and the return intake hole 401 is arranged to extend obliquely downward from inside to outside. Figure 6 As shown in FIG. 1, the upper portion of the piston 4 is formed with a return intake hole 401, the axis of the return intake hole 401 forms an acute angle (for example, 45°) with the axis of the central vent hole 400, the upper end of the return intake hole 401 communicates with the central vent hole 400, and the lower end of the return intake hole 401 penetrates the outer wall 40 of the piston, so that the central vent hole 400 communicates with the outside of the piston 4 through the return intake hole 401, and the return intake hole 401 is arranged to extend obliquely downward from inside to outside. Figure 1 As shown in FIG. 1, the upper portion of the piston 4 is formed with a return intake hole 401, the axis of the return intake hole 401 forms an acute angle (for example, 45°) with the axis of the central vent hole 400, the upper end of the return intake hole 401 communicates with the central vent hole 400, and the lower end of the return intake hole 401 penetrates the outer wall 40 of the piston, so that the central vent hole 400 communicates with the outside of the piston 4 through the return intake hole 401, and the return intake hole 401 is arranged to extend obliquely downward from inside to outside. Figure 2 As shown in FIG. 1, the upper portion of the piston 4 is formed with a return intake hole 401, the axis of the return intake hole 401 forms an acute angle (for example, 45°) with the axis of the central vent hole 400, the upper end of the return intake hole 401 communicates with the central vent hole 400, and the lower end of the return intake hole 401 penetrates the outer wall 40 of the piston, so that the central vent hole 400 communicates with the outside of the piston 4 through the return intake hole 401, and the return intake hole 401 is arranged to extend obliquely downward from inside to outside. Figure 6 As shown in FIG. 1, the upper portion of the piston 4 is formed with a return intake hole 401, the axis of the return intake hole 401 forms an acute angle (for example, 45°) with the axis of the central vent hole 400, the upper end of the return intake hole 401 communicates with the central vent hole 400, and the lower end of the return intake hole 401 penetrates the outer wall 40 of the piston, so that the central vent hole 400 communicates with the outside of the piston 4 through the return intake hole 401, and the return intake hole 401 is arranged to extend obliquely downward from inside to outside. Figure 1 As shown in FIG. 1, the upper portion of the piston 4 is formed with a return intake hole 401, the axis of the return intake hole 401 forms an acute angle (for example, 45°) with the axis of the central vent hole 400, the upper end of the return intake hole 401 communicates with the central vent hole 400, and the lower end of the return intake hole 401 penetrates the outer wall 40 of the piston, so that the central vent hole 400 communicates with the outside of the piston 4 through the return intake hole 401, and the return intake hole 401 is arranged to extend obliquely downward from inside to outside. Figure 6 As shown in FIG. 1, the upper portion of the piston 4 is formed with a return intake hole 401, the axis of the return intake hole 401 forms an acute angle (for example, 45°) with the axis of the central vent hole 400, the upper end of the return intake hole 401 communicates with the central vent hole 400, and the lower end of the return intake hole 401 penetrates the outer wall 40 of the piston, so that the central vent hole 400 communicates with the outside of the piston 4 through the return intake hole 401, and the return intake hole 401 is arranged to extend obliquely downward from inside to outside. Figure 5 As shown in FIG. 1, the upper portion of the piston 4 is formed with a return intake hole 401, the axis of the return intake hole 401 forms an acute angle (for example, 45°) with the axis of the central vent hole 400, the upper end of the return intake hole 401 communicates with the central vent hole 400, and the lower end of the return intake hole 401 penetrates the outer wall 40 of the piston, so that the central vent hole 400 communicates with the outside of the piston 4 through the return intake hole 401, and the return intake hole 401 is arranged to extend obliquely downward from inside to outside. Figure 1As shown, the outer wall of the plug-in end 41 and the return air cavity 720 between the return inner wall part 702 are formed, and the (up-down direction) piston outer wall 40 and the upper part of the air delivery needle 3 form the stroke air cavity 710, specifically, the upper part of the air delivery needle 3 forms a cap part, the cap part is connected with the inner wall of the sleeve 7 (radially), and the cap part is clamped between the inner step of the sleeve 7 and the lower end of the top joint 1, and the lower part of the top joint 1 is screwed into the upper end of the sleeve 7. The piston 4 has an upper position and a lower position relative to the sleeve 7; in the upper position, as shown, Figure 3 As shown, the air delivery hole 301 is connected with the stroke air cavity 710 through the stroke air inlet hole 402, as described above, because the stroke air inlet hole 402 is obliquely upwardly arranged from inside to outside, and, as shown, Figure 4 As shown, the stroke air inlet groove 4020 is formed on the piston outer wall 40, the stroke air inlet groove 4020 penetrates the piston 4 upwardly, and the outer end of the stroke air inlet hole 402 is connected with the stroke air inlet groove 4020, so that the air delivery hole 301 can be connected with the stroke air cavity 710 through the stroke air inlet hole 402, as shown, Figure 3 As shown, the plug-in end 41 is located above the sealing sleeve 5, that is, the plug-in end 41 has been moved upwardly away from the sealing sleeve 5, at this time, the upper part of the air delivery needle 3 closes the upper end of the return air inlet hole 401, and the lower end of the air delivery needle 3 is located below the inner end of the stroke air inlet hole 402, so that the compressed air cannot be discharged downwardly through the central air hole 400. In the lower position, as shown, Figure 1 As shown, the air delivery hole 301 is connected with the return air cavity 720 through the return air inlet hole 401, specifically, because the piston outer wall 40 has been moved downwardly out of the range of the air cylinder inner wall part 701, and, as shown, Figure 4 As shown, the return air inlet groove 4010 is formed on the piston outer wall 40, the outer end of the return air inlet hole 401 is connected with the return air inlet groove 4010, so that the compressed air can flow to the piston outer wall 40 and the return inner wall part 702 through the return air inlet groove 4010, and then the compressed air reaches between the return inner wall part 702 and the plug-in end 41; as shown, Figure 1 As shown, because the air delivery needle 3 is moved upwardly relative to the piston 4, the lower end of the air delivery needle 3 opens the inner end of the stroke air inlet hole 402, so that the stroke air cavity 710 is connected with the central air hole 400 through the stroke air inlet hole 402.

[0021] The working principle of the down-the-hole hammer drill tool with the air path structure of the utility model is briefly described as follows: as shown, Figure 1As shown, compressed air is input into the air inlet hole 101 of the top sub 1, the compressed air pushes the spool 21 of the one-way valve assembly 2 downward to overcome the elastic force of the reset spring of the one-way valve assembly 2, so that the compressed air enters into the air inlet cavity 10, then the compressed air enters into the air delivery needle 3, the compressed air flows downward through the air delivery needle 3 to the air delivery hole 301, the compressed air enters into the return air cavity 720 through the return air inlet hole 401, since the plug-in end 41 is adapted to be inserted into the sealing sleeve 5, thus the compressed air cannot flow into the central air hole 400 (almost), but the air in the stroke air cavity 710 can be discharged to the drill bit air jet hole 601 through the central air hole 400, the drill bit air jet hole 601 jets air outward to play a role of slag blowing, that is, during the upward movement (return stroke) of the piston 4, the sealing sleeve 5 separates the air inlet path from the air outlet path, so that the compressed air can push the piston 4 upward to return stroke. As shown, Figure 3 As shown, when the piston 4 moves upward to a certain amplitude, the piston outer wall 40 resets to the range of the inner wall part 701 of the cylinder, the compressed air flowing through the air delivery needle 3 enters into the stroke air cavity 710 through the stroke air inlet hole 402, thus the compressed air in the stroke air cavity 710 starts to push the piston 4 downward, since the plug-in end 41 has moved upward to move away from the sealing sleeve 5, at this time the air in the return air cavity 720 directly flows into the sealing sleeve 5, then the air in the return air cavity 720 is discharged to the drill bit air jet hole 601, again playing a role of slag blowing, as the piston 4 descends, then the plug-in end 41 is inserted into the sealing sleeve 5 again, and the piston 4 moves downward by inertia after acceleration to impact the upper end face of the drill bit 6 (specifically, the plug-in end 41 impacts the upper end face of the drill bit 6), so that the drill bit 6 plays a role of impacting the hole bottom, then the compressed air drives the piston 4 to return stroke, so on and so forth, during which the drilling machine drives the sleeve 7 to rotate through the top sub 1, and the sleeve 7 drives the drill bit 6 to rotate through the spline structure.

[0022] As can be seen from the above, since the sealing sleeve 5 is adapted to be arranged in the sleeve 7, thus the sleeve 7 radially positions the sealing sleeve 5, thus the upper end part of the drill bit 6 cannot move to drive the sealing sleeve 5 to move radially, so as to improve the coaxiality of the sealing sleeve 5 and the plug-in end 41, when the sealing sleeve 5 and the plug-in end 41 relatively reciprocate, it is beneficial to reduce the mutual collision and scraping of the sealing sleeve 5 and the plug-in end 41, so as to avoid the sealing sleeve 5 from being easily damaged, and since the scraping of the sealing sleeve 5 and the plug-in end 41 is reduced, the requirement for the elastic deformation ability of the sealing sleeve 5 is also greatly reduced, so that the sealing sleeve 5 can be made of steel, brass or ductile cast iron, further improving the durability of the sealing sleeve 5, so as to be beneficial to improve the durability of the impactor drill. The upper end of the sealing sleeve 5 can be chamfered to guide the plug-in end 41. Figure 1As shown, the air path structure of the utility model is provided with the structure of the gas delivery needle 3 for centralized air supply from inside to outside, so that the stroke air path and the return air path are switched directly, and the inclined directions of the return air inlet hole 401 and the stroke air inlet hole 402 are matched with the flow direction of the compressed air, which is beneficial to reduce the air flow resistance, facilitate the smoothness of the stroke air path and the return air path, and facilitate the flexible reciprocating movement of the piston.

[0023] Further, as shown in Figure 1 and Figure 2 , the upper end of the drill bit 6 is arranged in the lower part of the sealing sleeve 5, and the sealing ring 9 is arranged between the drill bit 6 and the inner wall of the sleeve 7, that is, the sealing ring 9 is arranged on the outer side of the drill bit 6, and the sealing sleeve 5 is attached to the upper side of the sealing ring 9, so that the compressed air leaked between the upper end of the drill bit 6 and the inner wall of the sleeve 7 is intercepted by the sealing ring 9, which is beneficial to the concentrated discharge of air through the drill bit air jet hole 601. As shown in Figure 2 , the lower part of the sleeve 7 is formed with a reverse step, and in the up-down direction, the sealing sleeve 5 is arranged between the reverse step and the sealing ring 9, and the lower end of the sleeve 7 is screwed with a compression sleeve, and the upper end of the compression sleeve is attached to the lower end of the sealing ring 9.

[0024] Further, as shown in Figure 2 and Figure 4 , the sealing ring 8 is arranged between the sealing sleeve 5 and the inner wall of the sleeve 7, and the number of the sealing ring 8 can be three, and the sealing ring 8 is arranged in the up-down direction, and by arranging the sealing ring 8, the leakage of compressed air between the sealing sleeve 5 and the inner wall of the sleeve 7 can be avoided when the piston 4 returns.

[0025] Further, as shown in Figure 1 , the upper end of the sleeve 7 is screwed with the top joint 1, the upper part of the top joint 1 is formed with the air inlet hole 101, the lower part of the top joint 1 is formed with the air inlet cavity 10, the lower end of the air inlet hole 101 is communicated with the top of the air inlet cavity 10, the one-way valve assembly 2 is arranged in the top joint 1, the one-way valve assembly 2 includes the valve core 21 for closing the lower end of the air inlet hole 101 and the valve seat 22, specifically, the lower end of the air inlet hole 101 is formed with a conical port, the upper end of the valve core 21 is pressed and attached to the conical port by the elastic force of the reset spring, the reset spring is coaxially arranged in the valve seat 22, the lower part of the valve core 21 is slidably connected in the valve seat 22, the lower end of the valve seat 22 is adaptively inserted into the cap part of the gas delivery needle 3, and the gas delivery needle 3 is formed with an air passage, as shown in Figure 1 and Figure 7As shown, the valve seat 22 is formed with valve seat air holes 2201 arranged in a circumferential direction, the number of the valve seat air holes 2201 can be four, the valve seat air holes 2201 are arranged gradually close to the axis of the valve seat 22 from top to bottom, that is, the valve seat air holes 2201 form an acute angle with the axis of the valve seat 22, the air inlet cavity 10 is communicated with the upper end of the gas delivery needle 3 through the valve seat air holes 2201, specifically, the upper end of the valve seat air holes 2201 is communicated with the air inlet cavity 10, the lower end of the valve seat air holes 2201 is communicated with the upper end of the air passage, and the gas delivery hole 301 is communicated with the lower end of the air passage. As shown in Figure 1 When compressed air is input into the air inlet hole 101, the compressed air overcomes the elastic force of the reset spring to open the conical port, so that the compressed air fills the air inlet cavity 10, and then the compressed air converges to the air passage through the valve seat air holes 2201, and the inclined direction of the valve seat air holes 2201 matches the airflow direction, which is beneficial to make the air flow smooth and reduce air resistance.

[0026] Further, as shown in Figure 4 The outer wall 40 of the piston is formed with a labyrinth seal groove 403, in other words, the labyrinth seal groove 403 is an annular groove, and the labyrinth seal groove 403 is arranged in parallel to the axis direction of the piston 4, as shown in Figure 3 The labyrinth seal groove 403 and the flat inner wall part 701 of the cylinder are combined to form a labyrinth seal structure, which can reduce the mutual leakage of the stroke gas cavity 710 and the return stroke gas cavity 720.

Claims

1. A pneumatic circuit structure for a down-the-hole impact drill bit, comprising an air supply needle (3), a drill bit (6), and a sleeve (7), wherein the air supply needle (3) is disposed in the upper part of the sleeve (7), the upper part of the drill bit (6) is slidably disposed in the lower end of the sleeve (7), and a piston (4) is provided inside the sleeve (7), characterized in that: The piston (4) has a central vent hole (400) and an outer piston wall (40) for abutting against the inner wall of the sleeve (7). The lower end of the air supply needle (3) is adapted to slide within the upper part of the central vent hole (400). The lower end of the air supply needle (3) has circumferentially distributed air supply holes (301). The upper part of the piston (4) has a return air inlet (401). The axis of the return air inlet (401) forms an acute angle with the axis of the central vent hole (400). The upper end of the return air inlet (401) communicates with the central vent hole (400). The lower end of the vent (401) penetrates the outer wall (40) of the piston. A stroke inlet (402) is formed on the upper part of the piston (4). The axis of the stroke inlet (402) forms an acute angle with the axis of the central vent (400). The lower end of the stroke inlet (402) is connected to the central vent (400). The upper end of the stroke inlet (402) penetrates the outer wall (40) of the piston. The return inlet (401) and the stroke inlet (402) are circumferentially offset. The inner end of the return inlet (401) is located above the inner end of the stroke inlet (402). A sealing sleeve (5) is fitted inside the sleeve (7). A plug-in end (41) is formed at the lower end of the piston (4). The plug-in end (41) can be slidably connected to the upper part of the sealing sleeve (5). The drill bit (6) has a drill bit air vent (601). The upper end of the drill bit air vent (601) is aligned with the lower end of the central vent (400). A return air chamber (720) is formed between the piston outer wall (40) and the upper end of the sealing sleeve (5). A return air chamber (720) is formed between the piston outer wall (40) and the upper part of the air needle (3). There is a stroke air chamber (710), and the piston (4) has an upper position and a lower position relative to the sleeve (7); in the upper position, the air supply port (301) is connected to the stroke air chamber (710) through the stroke air inlet port (402), and the plug end (41) is located above the sealing sleeve (5); in the lower position, the air supply port (301) is connected to the return air chamber (720) through the return air inlet port (401), and the stroke air chamber (710) is connected to the central vent (400) through the stroke air inlet port (402).

2. The air circuit structure of a down-the-hole impact drill bit according to claim 1, characterized in that: The upper end of the drill bit (6) is located inside the lower part of the sealing sleeve (5), and a sealing ring (9) is provided between the drill bit (6) and the inner wall of the sleeve (7). The sealing sleeve (5) is attached to the upper side of the sealing ring (9).

3. The air passage structure of a down-the-hole impact drill bit according to claim 2, characterized in that: A sealing ring (8) is provided between the sealing sleeve (5) and the inner wall of the sleeve (7).

4. The air circuit structure of a down-the-hole impact drill bit according to claim 1, characterized in that: The upper end of the sleeve (7) is equipped with a top connector (1), an air inlet (101) is formed in the upper part of the top connector (1), and an air inlet chamber (10) is formed in the lower part of the top connector (1). The lower end of the air inlet (101) is connected to the top of the air inlet chamber (10). A one-way valve assembly (2) is provided in the top connector (1). The one-way valve assembly (2) includes a valve seat (22) and a valve core (21) for closing the lower end of the air inlet (101). The lower part of the valve core (21) is slidably connected to the valve seat (22). The valve seat (22) is formed with circumferentially distributed valve seat vent holes (2201). The valve seat vent holes (2201) are arranged from top to bottom and gradually approach the axis of the valve seat (22). The air inlet chamber (10) is connected to the upper end of the air supply needle (3) through the valve seat vent holes (2201).

5. The air circuit structure of a down-the-hole impact drill bit according to claim 1, characterized in that: A labyrinth sealing groove (403) is formed on the outer wall (40) of the piston.

Images