Impact structure for rock drill and rock drill

Abstract

The present application provides an impact structure for a rock drill and a rock drill, wherein the impact structure for the rock drill includes a piston, a cylinder sleeve assembly and an oil distribution valve, wherein a cavity for inserting the piston is provided in the cylinder sleeve assembly, and the piston can make axial reciprocating motion in the cavity; wherein the cavity includes a piston front cavity and a piston rear cavity, and an oil passage for connecting with the piston front cavity and the piston rear cavity is provided on the cylinder sleeve assembly, and the piston front cavity is always kept inflowing with oil; the oil distribution valve is sleeved on the piston, and the oil distribution valve can make reciprocating motion along the axial direction of the piston, so as to change the connection relationship between the piston rear cavity and the oil passage, thereby assisting the piston in reversing. The oil distribution valve of the impact structure is a sleeve valve type, which can effectively reduce the oil circuit and shorten the piston length; the working surface of the oil distribution valve is large, so that the reversing efficiency of the oil distribution valve is high, which is conducive to the auxiliary reversing effect on the piston; and the rock drill includes the above-mentioned impact structure, the piston of the rock drill is short, the overall structure of the rock drill is compact, the volume is small, and the impact efficiency is high.

Description

Technical Field

[0001] This application relates to the field of rock drill technology, specifically to an impact structure for a rock drill and a rock drill. Background Technology

[0002] A rock drill is a tool used for quarrying stone, mainly consisting of an impact mechanism and a rotary mechanism. The impact mechanism includes a cylinder and an impact piston that slides back and forth within the cylinder. The rotary mechanism includes a chisel. When the impact piston extends out of the cylinder to its limit position, it strikes the chisel, which transmits the impact force to the rock to create a hole.

[0003] In an impact structure, a cylinder liner, piston, and directional valve are typically included. The directional valve assists in piston reversal. In the prior art, refer to Chinese patent CN219035193U, which provides a graded braking impact device and a rock drill. The graded braking impact device includes a housing, cylinder liner, directional valve, and piston. The piston and directional valve are coaxially mounted within the cylinder liner. The inner wall of the cylinder liner has several pressure equalization grooves. The cylinder liner is installed within the housing, which has a main oil inlet and a main oil return path. The cylinder liner has a branch oil inlet path connected to the main oil inlet path and a branch oil return path connected to the main oil return path. Oil passes through the housing, cylinder liner, piston, and directional valve, contacting them. The side of the piston closer to the drill bit is called the front, and the side farther from the drill bit is called the rear. The front end of the piston is connected to the drill bit, and the rear end of the piston is intermittently or in contact with the directional valve.

[0004] Reference Appendix Figure 14 The diagram shown is a structural schematic of the graded braking impact device of this patent, in conjunction with the attached diagram. Figure 14 It is known that the reversing valve 3 is located at the rear end of the piston 4. This impact structure increases the length of the piston, making the overall volume of the rock drill larger and less compact. Furthermore, the interaction area between the reversing valve and the piston is limited to the rear end of the piston. The interaction area between the reversing valve and the piston is small, and the reversing valve's assist in the reversing of the piston is relatively small, resulting in low reversing efficiency of the piston, which is not conducive to the high-frequency motion development of the rock drill. Summary of the Invention

[0005] To address the aforementioned technical problems, this application provides, on the one hand, an impact structure for a rock drill, wherein the oil distribution valve is a sleeve valve type, which has a large action area on the piston and a good assisting effect on piston reversal, which can facilitate piston reversal and effectively shorten the piston length; on the other hand, this application also provides a rock drill whose impact structure has a relatively short piston length and a compact structure, which can reduce the overall size of the rock drill and is conducive to the development of high-frequency motion of the rock drill.

[0006] On the one hand, this application provides an impact structure for a rock drill, including a piston, a cylinder liner assembly and an oil distribution valve, wherein the cylinder liner assembly is provided with a cavity for the piston to be inserted, and the piston can perform axial reciprocating motion within the cavity;

[0007] The cavity includes a piston front chamber and a piston rear chamber. The cylinder liner assembly is provided with an oil passage for communicating with the piston front chamber and the piston rear chamber. The piston front chamber is always kept in oil supply.

[0008] The oil distribution valve is sleeved on the piston step of the piston. The oil distribution valve can reciprocate along the axial direction of the piston to change the connection between the piston rear chamber and the oil passage, thereby assisting the piston to reverse.

[0009] Compared with the prior art, the impact structure for a rock drill of this application has a sleeve valve for the oil distribution valve, which is sleeved on the piston. This can effectively reduce the oil passage and shorten the piston length. The working surface between the oil distribution valve and the piston is large, which makes the oil distribution valve have high commutation efficiency and is beneficial to the auxiliary commutation of the piston.

[0010] The oil distribution valve is located in the rear chamber of the piston. The valve moves axially within the rear chamber, altering the connection between the rear chamber and the oil passage. This changes the hydraulic force acting on the rear end of the piston, assisting in its reciprocating motion within the chamber. The front chamber of the piston is always supplied with oil, meaning the piston tip is always under force. The oil distribution valve changes the force acting on the rear end of the piston, comparing the forces acting on the front and rear ends to move the piston forward or backward. When the oil distribution valve moves to connect the rear chamber's oil passage with the oil inlet, the forward force on the rear end is greater than the backward force on the front end, causing the piston to move forward. Conversely, when the oil distribution valve moves to connect the rear chamber's oil passage with the oil inlet, the forward force on the rear end is less than the backward force on the front end, causing the piston to move backward. This design allows the oil distribution valve to act only on the oil passage of the rear chamber, effectively controlling piston reversal. It is a simple structure with high efficiency.

[0011] In some optional embodiments, the oil passage of the piston front chamber includes a front chamber oil inlet passage and a front chamber oil return passage, wherein the front chamber oil inlet passage is always connected;

[0012] The oil passage in the piston rear chamber includes an oil inlet passage and an oil return passage.

[0013] The front chamber oil inlet passage, the front chamber oil return passage, the rear chamber oil return passage, and the rear chamber oil inlet passage are arranged sequentially along the axial direction of the piston.

[0014] In some alternative embodiments, the piston front chamber is provided with a braking front chamber for braking the piston stroke;

[0015] The piston rear chamber is provided with a braking rear chamber for braking the piston return stroke.

[0016] In some optional embodiments, the cylinder liner assembly is further provided with a signal judgment oil circuit, which is divided into a piston judgment oil circuit and a distribution valve judgment oil circuit.

[0017] The piston judgment oil passage is located between the front chamber inlet oil passage and the front chamber return oil passage;

[0018] The oil distribution valve is positioned between the return oil circuit of the rear cavity and the inlet oil circuit of the rear cavity.

[0019] In some optional embodiments, the cylinder liner assembly is provided with a distribution valve chamber for mounting a distribution valve;

[0020] The oil distribution valve cavity is provided with a valve braking cavity, which is used to brake the oil distribution valve;

[0021] The oil distribution valve chamber is provided with a valve return oil passage, which is connected to the valve braking chamber.

[0022] The valve return oil circuit is located between the oil distribution valve judgment oil circuit and the rear chamber inlet oil circuit.

[0023] In some optional embodiments, the piston has a front working surface at its front end and a rear working surface at its rear end;

[0024] The area of ​​the front action surface is smaller than the area of ​​the rear action surface;

[0025] The ratio of the area of ​​action of the front action surface to the area of ​​action of the rear action surface is approximately 1:3.

[0026] In some optional embodiments, bushings are respectively fitted at the front and rear ends of the piston, and lubrication oil passages are provided at the front and rear ends of the piston to prevent the piston from dry friction with the bushings.

[0027] In some optional embodiments, the piston movement process includes a return motion, which includes a return acceleration phase and a return braking phase. The piston return acceleration phase has a stroke of L1, and the return braking distance is X, where L1 ≥ 2X.

[0028] The set stroke of the piston before entering the brake chamber is L2, where L2≥2L1;

[0029] The axial length of the brake cavity is L5, where X > L5.

[0030] In some optional embodiments, the piston movement process includes a stroke movement, and the piston is preset with a first safety distance L3 during the stroke movement. The first safety distance is the distance before the piston impacts and enters the braking front chamber, wherein L3 is greater than the normal drilling depth of the rock drill.

[0031] The piston has a preset second safety distance L4 during its stroke, which is the axial length of the brake front chamber, where L4 > L3.

[0032] The impact structure for a rock drill disclosed in this application has at least the following technical advantages:

[0033] The piston front chamber is set to a constant pressure state and is always connected to the oil inlet. The oil distribution valve is sleeved on the rear end of the piston. The oil distribution valve changes the connectivity of the oil passage in the rear chamber of the piston, that is, it changes the magnitude of the force on the rear end of the piston. This, in turn, works with the force on the front end of the piston to make the piston reciprocate in the axial direction within the chamber. This makes the impact structure of the rock drill relatively simple. The sleeve valve type oil distribution valve effectively shortens the piston length, resulting in fewer oil passages in the impact structure. Furthermore, the oil distribution valve has a large effective area, which improves the reversing effect on the piston.

[0034] By setting up a front brake chamber and a rear brake chamber, a safe braking effect can be achieved on the piston's stroke and return stroke, preventing the piston from impacting the cylinder and providing hydraulic protection for the piston.

[0035] By setting signals to determine the oil circuit, position information can be provided to the oil distribution valve, so that the oil distribution valve can better assist the piston's reciprocating motion in the cavity.

[0036] By rationally setting the area ratio of the piston's front working surface to its rear working surface, the impact mechanism can have greater impact energy, and the return braking time can be reduced, thereby increasing the impact frequency.

[0037] Secondly, this application also provides a rock drill, which includes an impact structure for rock drills as described in any of the above embodiments. The impact structure of the rock drill of this application has a shorter piston, resulting in a compact overall structure and smaller size; moreover, it has higher impact efficiency, greatly enhancing the working efficiency of the rock drill. Attached Figure Description

[0038] Figure 1 This is a cross-sectional schematic diagram of an anti-jamming structure for a rock drill according to an embodiment of this application;

[0039] Figure 2 This is a cross-sectional schematic diagram of the first movement stage of an impact structure for a rock drill according to an embodiment of this application;

[0040] Figure 3 This is a cross-sectional schematic diagram of the second movement stage of an impact structure for a rock drill according to an embodiment of this application;

[0041] Figure 4 This is a cross-sectional schematic diagram of the third movement stage of the impact structure for a rock drill according to an embodiment of this application;

[0042] Figure 5 This is a cross-sectional schematic diagram of the fourth movement stage of the impact structure for a rock drill according to an embodiment of this application;

[0043] Figure 6 This is a cross-sectional schematic diagram of the fifth movement stage of an impact structure for a rock drill according to an embodiment of this application;

[0044] Figure 7 yes Figure 1 A magnified schematic diagram of part A;

[0045] Figure 8 yes Figure 2 A magnified view of a portion of the image;

[0046] Figure 9 yes Figure 3 A magnified view of a portion of the image;

[0047] Figure 10 yes Figure 4 A magnified view of a portion of the image;

[0048] Figure 11 yes Figure 5 A magnified view of a portion of the image;

[0049] Figure 12 yes Figure 6 A magnified view of a portion of the image;

[0050] Figure 13 yes Figure 1 A magnified schematic diagram of part B;

[0051] Figure 14 This is a schematic diagram of the structure of a graded braking impact device in the prior art.

[0052] Figure label:

[0053] 1. Oil distribution valve; 2. Cylinder liner assembly; 3. Piston; 4. Bushing;

[0054] 11. Braking unit; 12. Oil float tank;

[0055] 21. Piston front chamber; 22. Piston rear chamber; 23. Signal judgment oil circuit; 24. Oil distribution valve chamber;

[0056] 211. Front chamber oil inlet passage; 212. Front chamber oil return passage; 213. Braking front chamber;

[0057] 221. Rear chamber oil inlet passage; 222. Rear chamber oil return passage; 223. Brake rear chamber;

[0058] 231. Piston determines the oil circuit; 232. Distributor valve determines the oil circuit;

[0059] 241. Valve braking chamber; 242. Valve return oil circuit; 243. Variable oil chamber;

[0060] 31. Front working surface; 32. Rear working surface; 33. Piston step;

[0061] 41. Lubrication circuit. Detailed Implementation

[0062] To enable those skilled in the art to better understand the technical solutions of this disclosure, the following detailed, clear, and complete description of this disclosure is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this disclosure and are not intended to limit it.

[0063] In the description of this application, the use of "first" and "second" is for the purpose of distinguishing technical features only, and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated or the order of the technical features indicated.

[0064] Those skilled in the art should understand that in the disclosure of this application, the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limitations on this application.

[0065] The present application will now be described in further detail with reference to the accompanying drawings, see below. Figures 1 to 14 illustrate.

[0066] Firstly, such as Figure 1 , Figure 7As shown, this application provides an impact structure for a rock drill. This impact structure is suitable for hydraulic rock drills. When working, it causes the piston 3 to perform high-frequency reciprocating motion, continuously impacting the drill bit. The drill bit then applies impact force to the rock, thereby shearing the rock. In this embodiment, the impact structure includes a piston 3, a cylinder liner assembly 2, and a distribution valve 1 (also called a reversing valve). The cylinder liner assembly 2 has a cavity for the piston 3 to be inserted into. Part of the piston 3 is located in the cavity, and the piston 3 can perform axial reciprocating motion within the cavity. The distribution valve 1 is coaxially arranged with the piston 3, and both the distribution valve 1 and the piston 3 can perform reciprocating motion along the same axis within the cavity.

[0067] The cavity includes a piston front cavity 21 and a piston rear cavity 22. The piston front cavity 21 corresponds to the front end of the piston 3, and the piston rear cavity 22 corresponds to the rear end of the piston 3. The cylinder liner assembly 2 is provided with an oil passage for connecting with the piston front cavity 21 and the piston rear cavity 22. The external oil supply device supplies high-pressure oil to or returns high-pressure oil to the piston rear cavity 22 or the piston front cavity 21 through the oil passage. Through the action of the hydraulic oil and the piston 3, a force is generated on the piston 3.

[0068] In this embodiment, the piston front chamber 21 is always kept in oil supply, meaning that the front end of the piston 3 is always subjected to force. The oil distribution valve 1 is sleeved on the piston step 33 of the piston 3 and is located in the piston rear chamber 22. The oil distribution valve 1 reciprocates along the axial direction of the piston 3 to change the connection between the piston rear chamber 22 and the oil passage, thereby assisting the piston 3 in reversing direction. When the oil distribution valve 1 moves to connect the oil passage of the piston rear chamber 22 with the oil inlet, the forward force on the rear end of the piston 3 is greater than the backward force on the front end of the piston 3, so the piston 3 moves forward. When the oil distribution valve 1 moves to connect the oil passage of the piston rear chamber 22 with the oil inlet, the forward force on the rear end of the piston 3 is less than the backward force on the front end of the piston 3, so the piston 3 moves backward.

[0069] That is, the oil distribution valve 1 only needs to change the connection between the oil passage in the rear chamber 22 of the piston and the piston 3 to achieve the assisted reversing of the piston 3. Therefore, for the overall impact structure, the number of oil passages in the piston 3 is relatively small, and the structure is relatively simple. Compared with the existing technology that places the oil distribution valve 1 on the rear end face of the piston 3, the sleeve valve structure of this embodiment makes the working surface between the oil distribution valve 1 and the piston 3 larger, resulting in high reversing efficiency of the oil distribution valve 1, which is beneficial to the assisted reversing of the piston 3. Figure 7 As shown, the oil distribution valve 1 is directly fitted onto the piston step 33, which can effectively shorten the length of the piston 3, making the impact structure more compact.

[0070] Furthermore, such as Figure 1 , Figure 7As shown, the oil passage of the piston front chamber 21 includes the front chamber oil inlet passage 211 and the front chamber oil return passage 212. The front chamber oil inlet passage 211 is always connected, that is, no matter where the piston 3 moves in the chamber, the front chamber oil inlet passage 211 always keeps oil in, that is, the front end of the piston 3 is always subjected to the force of the hydraulic oil in the front chamber oil inlet passage 211, so that the piston front chamber 21 is in a constant pressure state.

[0071] The oil passage of the piston rear chamber 22 includes a rear chamber inlet oil passage 221 and a rear chamber return oil passage 222. When the distribution valve 1 performs axial reciprocating motion, since the oil passage is located on the cylinder body and the distribution valve 1 is located between the cylinder body and the piston 3, the distribution valve 1 can block the oil passage to change the connection between the rear chamber inlet oil passage 221 or the rear chamber return oil passage 222 and the piston rear chamber 22. When the rear chamber inlet oil passage 221 is connected to the piston rear chamber 22, the hydraulic oil exerts a force on the rear end of the piston 3, and the force on the rear end of the piston 3 increases; when the rear chamber return oil passage 222 is connected to the piston rear chamber 22, the force on the rear end of the piston 3 decreases.

[0072] In this embodiment, as Figure 7 As shown, the front chamber oil inlet passage 211, the front chamber oil return passage 212, the rear chamber oil return passage 222, and the rear chamber oil inlet passage 221 are arranged sequentially along the axial direction of the piston 3. The advantage of this arrangement is that the pressure of the hydraulic oil on the piston 3 is concentrated at the front and rear ends of the piston 3, which can effectively enhance the effect of the piston 3 moving forward and backward, and improve the efficiency of the piston 3 in reciprocating motion.

[0073] Furthermore, such as Figure 7 As shown, the piston front chamber 21 is provided with a braking front chamber 213 for braking the piston 3 during its stroke, and the braking front chamber 213 is located at the relatively forward end of the piston 3; the piston rear chamber 22 is provided with a braking rear chamber 223 for braking the piston 3 during its return stroke, and the braking rear chamber 223 is located at the rear end of the piston 3. In this embodiment, the braking front chamber 213 and the braking rear chamber 223 are essentially braking dead chambers, which can provide a safe braking effect during the piston 3's stroke and return stroke, preventing the piston 3 from impacting the cylinder block and providing hydraulic protection for the piston 3. In this embodiment, the braking front chamber 213 is located in front of the front chamber oil inlet passage 211, and the braking rear chamber 223 is located behind the rear chamber oil inlet passage 221.

[0074] Furthermore, such as Figure 7As shown, the cylinder liner assembly 2 is also provided with a signal judgment oil circuit 23, which is divided into a piston judgment oil circuit 231 and a distribution valve judgment oil circuit 232. The piston judgment oil circuit 231 is located between the front chamber oil inlet oil circuit 211 and the front chamber oil return oil circuit 212, so the piston judgment oil circuit 231 can be connected to the front chamber oil return oil circuit 212 or the front chamber oil inlet oil circuit 211. The distribution valve judgment oil circuit 232 is located between the rear chamber oil return oil circuit 222 and the rear chamber oil inlet oil circuit 221. In this embodiment, the signal judgment oil circuit 23 can provide position information to the oil distribution valve 1. When the piston 3 moves to the designated position, the connection between the signal judgment oil circuit 23 and the oil circuit channel of the piston 3 will change. The piston judgment oil circuit 231 is connected to the oil distribution valve judgment oil circuit 232. When the piston judgment oil circuit 231 is connected to the front chamber inlet oil circuit 211 or the front chamber return oil circuit 212, it can act on the oil distribution valve 1. Therefore, the oil distribution valve 1 can obtain the position of the piston 3 through the signal judgment oil circuit 23, so that the oil distribution valve 1 can switch in time to assist the piston 3 in switching.

[0075] Furthermore, such as Figure 7 As shown, the cylinder liner assembly 2 is provided with a distribution valve chamber 24 for installing the distribution valve 1. The distribution valve chamber 24 is connected to the piston rear chamber 22, the rear chamber oil inlet passage 221, and the rear chamber oil return passage 222. By setting the distribution valve chamber 24, it is possible to ensure that the distribution valve 1 has an auxiliary reversing function for the piston 3, and at the same time, it can limit the axial and radial movement of the distribution valve 1 relative to the piston 3.

[0076] like Figure 7 As shown, the distribution valve chamber 24 is provided with a valve braking chamber 241, which is used to brake the distribution valve 1; the distribution valve chamber 24 is provided with a valve return oil passage 242, which is connected to the valve braking chamber 241; the valve return oil passage 242 is located between the distribution valve judgment oil passage 232 and the rear chamber inlet oil passage 221, thereby acting as a barrier between the distribution valve judgment oil passage 232 and the rear chamber inlet oil passage, so that the force on the distribution valve 1 is concentrated at both ends, which can effectively improve the switching sensitivity of the distribution valve 1.

[0077] Furthermore, such as Figure 7 As shown, the valve braking chamber 241 includes a valve braking front chamber and a valve braking rear chamber. The oil distribution valve 1 is provided with a braking part 11 that works in conjunction with the valve braking chamber 241. Through the cooperation between the braking part 11 of the oil distribution valve 1 and the valve braking chamber 241, the oil distribution valve 1 can smoothly decelerate to the limit position, reducing the damage caused by the impact of the oil distribution valve 1.

[0078] Furthermore, such as Figure 13As shown, the distribution valve chamber 24 is also provided with a variable oil chamber 243. The variable oil chamber 243 is located at the front end of the distribution valve 1. The variable oil chamber 243 is connected to the distribution valve judgment oil passage 232. The variable oil chamber 243 is located between the valve braking chamber 241 and the rear chamber return oil passage 222. After the variable oil chamber 243 is connected to the distribution valve judgment oil passage 232, the connection relationship of the oil passage between the piston rear chamber 22 and the piston front chamber 21 caused by the change of the piston 3's movement position is then applied to the front end of the distribution valve 1, causing the force on the front end of the distribution valve 1 to change, thereby assisting the distribution valve 1 in reversing.

[0079] Furthermore, such as Figure 13 As shown, the variable oil chamber 243 of the oil distribution valve 1 has an action part, and the action area of ​​the action part is larger than the action area of ​​the rear end of the oil distribution valve 1.

[0080] Furthermore, such as Figure 13 As shown, the piston step 33 is provided with a relief groove, which is recessed towards the center of the piston 3. By providing the relief groove, when the oil distribution valve 1 makes an axial displacement relative to the piston 3, there is oil lubrication between the oil distribution valve 1 and the piston 3, and dry friction will not occur.

[0081] Furthermore, such as Figure 13 As shown, at least one floating oil groove 12 is provided on the outer peripheral wall of the distribution valve 1. The floating oil groove 12 is recessed towards the central axis of the piston 3 and is annular. The floating oil groove 12 is evenly distributed on the distribution valve 1, so that the distribution valve 1 is subjected to a relatively even overall supporting force from the floating oil groove 12, and the distribution valve 1 is balanced by force. By providing the floating oil groove 12 on the distribution valve 1, the hydraulic oil can flow into the floating oil groove 12, thereby providing a supporting force to the distribution valve 1, thereby effectively reducing the eccentricity of the distribution valve 1 due to lateral force and the resulting hydraulic jamming force, thus preventing the distribution valve 1 from jamming.

[0082] In another optional embodiment of this application, such as Figure 7 As shown, the piston 3 has a front working surface 31 at its front end and a rear working surface 32 at its rear end. The front working surface 31 and the rear working surface 32 are arranged facing each other. When the front working surface 31 is subjected to hydraulic pressure, it generates a backward force on the piston 3. When the rear working surface 32 is subjected to hydraulic pressure, it generates a forward force on the piston 3. The working area of ​​the front working surface 31 is smaller than that of the rear working surface 32. This ensures that the rock drill has a large impact energy under a certain stroke and reduces the return braking time, thereby increasing the impact frequency of the rock drill.

[0083] Furthermore, the ratio of the area of ​​action of the front action surface 31 to the area of ​​action of the rear action surface 32 is basically 1:3; under this ratio, the impact energy of the impact structure is better, the return braking time is relatively small, and the impact frequency of the rock drill is better.

[0084] Furthermore, such as Figure 7 As shown, the rear action surface 32 is basically a plane, which is set along the radial direction of the piston 3 and is basically parallel to the radial plane. The advantage of this setting is that when the hydraulic pressure acts on the rear action surface 32, the thrust generated on the piston 3 is basically parallel to the axial direction of the piston 3, and the working efficiency of the hydraulic oil and the rear action surface 32 is greatly improved, which enables the piston 3 to have a greater forward impact force and a faster speed.

[0085] In another optional embodiment of this application, such as Figure 1 As shown, the piston 3 is fitted with bushings 4 at its front and rear ends, and lubrication oil passages 41 are provided at the front and rear ends of the piston 3. The lubrication oil passages 41 are always connected to the return oil. The lubrication oil passages 41 are used to prevent the piston 3 from dry friction with the bushings 4, thereby extending the service life of the piston 3 and the bushings 4, and improving the sensitivity of the piston 3.

[0086] In another optional embodiment of the impact structure for rock drills in this application, the piston 3 movement process includes a return motion to form a reciprocating motion of the piston 3 in the cavity; the return motion of the piston 3 includes a return acceleration phase and a return braking phase, the stroke of the piston 3 in the return acceleration phase is L1, and the return braking distance is X, wherein L1≥2X. The advantage of this setting is that it can speed up the return speed of the piston 3, reduce the return time of the piston 3, and thus improve the impact rate of the impact structure.

[0087] Furthermore, the set stroke of piston 3 before entering the brake rear chamber 223 is L2, where L2≥2L1; the advantage of this setting is that even if the pressure on piston 3 may be unstable, by setting the set stroke of piston 3 before entering the brake rear chamber 223 to be greater than the stroke during the return acceleration phase, piston 3 can enter the return braking phase more smoothly, thereby preventing piston 3 from being unable to decelerate due to excessive speed during the return acceleration phase and impacting the cylinder body, thus effectively protecting piston 3 during the return stroke.

[0088] Furthermore, the axial length of the braking cavity 223 is L5, where X > L5. The advantage of this setting is that when the drill bit of the rock drill goes too far forward, the piston 3 can further rely on the dead cavity to decelerate and brake the piston 3 during the return stroke, reducing the damage caused by the piston 3 hitting the cylinder.

[0089] Furthermore, the movement of piston 3 includes a stroke motion, in which piston 3 strikes the drill bit. During the stroke motion, piston 3 is pre-set with a first safety distance L3, which is the distance before piston 3 strikes and enters the braking front chamber 213. L3 is greater than the normal drilling depth of the rock drill. The advantage of this setting is that it can ensure that under normal rock drilling conditions, piston 3 will not enter the braking front chamber 213, thus preventing the loss of impact energy and the reduction of impact frequency, thereby improving the rock drill efficiency.

[0090] Furthermore, the piston 3 has a preset second safety distance L4 during its stroke, which is the axial length of the braking front chamber 213, where L4 > L3. The advantage of this is that when the drill bit of the rock drill goes too far forward, the piston 3 can be further decelerated and braked by the braking front chamber 213 after impact, reducing the impact on the cylinder and causing damage to the piston 3.

[0091] In this application, as Figure 1 As shown, the front chamber oil inlet line 211 and the rear chamber oil inlet line 221 are both connected to high-voltage accumulators, and the front chamber oil return line 212 and the rear chamber oil return line 222 are both connected to low-voltage accumulators. This is existing technology and will not be described in detail here.

[0092] The working process of the impact structure for the rock drill of this application includes five stages. The piston 3 of the impact structure moves in a return process and a stroke process. The piston 3 in the return process includes an initial stage of return acceleration, an intermediate stage of return acceleration, and a return braking stage. The piston 3 in the stroke process includes a stroke stage and an impact stage.

[0093] Specific combination Figures 2 to 12 As shown:

[0094] Phase one refers to the motion of piston 3 from its initial state to the initial stage of return acceleration; for example... Figure 2 , Figure 8 As shown, the initial position of piston 3 is that piston 3 is located at the impact point. In this stage, the normal oil inlet of the front chamber is connected, the piston front chamber 21 is in the oil inlet state, the signal judgment oil passage 23 is in the oil inlet state, the piston judgment oil passage 231 is connected to the normal oil inlet of the front chamber, that is, the oil distribution valve judgment oil passage 232 is connected to the oil distribution valve 1, the variable oil chamber 243 of the oil distribution valve 1 is in the oil inlet state, the front end of the oil distribution valve 1 is subjected to the force of high pressure oil, and the force-bearing area of ​​the front end of the oil distribution valve 1 is greater than the force-bearing area of ​​the rear end. Therefore, the oil distribution valve 1 moves to the rear end. The oil distribution valve 1 moves backward until it blocks the oil inlet of the piston rear chamber 22, and makes the oil return passage 222 of the piston rear chamber 3 connected to the piston rear chamber 22. The force at the front end of piston 3 is greater than that at the rear end, so piston 3 moves backward with acceleration.

[0095] Phase two refers to the motion of piston 3 from the initial stage of return acceleration to the intermediate stage of return acceleration; for example... Figure 3 , Figure 9 As shown, during the acceleration phase in the return stroke, the piston judgment oil passage 231 is disconnected from the front chamber oil inlet oil passage 211, and the oil distribution valve judgment oil passage 232 is also disconnected from the front chamber oil inlet oil passage 211. Furthermore, during this phase, the piston judgment oil passage 231 is not connected to the front chamber return oil passage 212, and the variable oil chamber 243 of the oil distribution valve 1 becomes a dead chamber. The pressure in the dead chamber remains unchanged, and the pressure at the front end of the oil distribution valve 1 is greater than that at the rear end, so it remains stationary. The signal judgment oil passage 23 does not receive or return oil. The rear chamber return oil passage 222 is connected to the piston rear chamber 22. Therefore, the force on the front end of the piston 3 is greater than that on the rear end, and the piston 3 continues to accelerate and move backward.

[0096] Phase three refers to the movement of piston 3 from the return acceleration phase to the return braking phase; for example... Figure 4 , Figure 10 As shown, the piston determines that the oil passage 231 is connected to the front chamber return oil passage 212. The signal determines that the oil passage 23 is in the return state. The variable oil chamber 243 of the distribution valve 1 returns oil. The oil pressure at the front end of the distribution valve 1 decreases. The distribution valve 1 moves forward to the frontmost position. The rear chamber inlet oil passage 221 is connected to the piston rear chamber 22. The working area of ​​the piston rear chamber 22 is larger than that of the front chamber. The piston 3 performs a return braking motion.

[0097] Phase four refers to the movement of piston 3 from the return braking phase to the stroke phase; for example... Figure 5 , Figure 11 As shown, the oil distribution valve 1 is located at the front end, the piston rear chamber 22 is connected to the rear chamber oil inlet passage 221, the signal determines that the oil passage 23 is in the oil return state, the working area of ​​the piston rear chamber 22 is larger than that of the front chamber, the piston 3 moves forward, this is the piston 3 making stroke motion.

[0098] Phase five is the motion process from the piston's third stroke to impact; such as Figure 6 , Figure 12 As shown, the piston determines that the oil passage 231 is connected to the front chamber oil inlet passage 211, and the signal determines that the oil passage 23 is in the oil inlet state, that is, the variable oil chamber 243 of the oil distribution valve 1 is inlet. The rear end of the oil distribution valve 1 is affected by the rear chamber oil inlet passage 221. The forces on both ends of the oil distribution valve 1 are opposite, but because the area of ​​the variable oil chamber 243 is larger, the force on the front end of the oil distribution valve 1 is greater than that on the rear end, and the oil distribution valve 1 moves backward.

[0099] After the oil distribution valve 1 completes the reversal, the piston 3 reaches the last side. The oil inlet passage 211 of the piston front chamber 21 is always inlet. The piston rear chamber 22 is about to be connected to the rear chamber return passage 222, and the piston 3 will collide.

[0100] When the oil distribution valve 1 moves backward, it blocks the oil inlet passage 221 of the rear chamber, and the oil return passage 222 of the rear chamber is connected to the piston 3, and the piston 3 enters the return stroke stage.

[0101] Secondly, this application also provides a rock drill, which includes the impact structure for rock drills in any of the above embodiments. The piston 3 of the impact structure of the rock drill of this application is shorter, making the overall structure of the rock drill compact and its size smaller; moreover, the impact efficiency of the rock drill is higher, greatly enhancing the working efficiency of the rock drill.

[0102] It should be noted that the various embodiments of this application can be arbitrarily combined into new embodiments, provided that the solutions do not conflict and the technical solutions can coexist.

[0103] The present application has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present application. The descriptions of the embodiments above are only for the purpose of helping to understand the present application and its core ideas. It should be noted that those skilled in the art can make several improvements and modifications to the present application without departing from the principles of the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.

Claims

1. An impact structure for a rock drill, characterized in that: It comprises a piston (3), a cylinder sleeve assembly (2) and an oil distribution valve (1); the cylinder sleeve assembly (2) is provided with a cavity for the piston (3) to be inserted into, and the piston (3) can perform axial reciprocating motion in the cavity; The cavity comprises a piston front cavity (21) and a piston rear cavity (22), and the cylinder sleeve assembly (2) is provided with an oil passage for connecting with the piston front cavity (21) and the piston rear cavity (22), and the piston front cavity (21) is always filled with oil; The oil distribution valve (1) is sleeved on the piston step (33) of the piston (3), and the oil distribution valve (1) can reciprocate along the axial direction of the piston (3) to change the communication relationship between the piston rear cavity (22) and the oil passage, thereby assisting the reversal of the piston (3); The piston rear chamber (22) is provided with a braking rear chamber (223) for braking the return stroke of the piston (3); The front end of the piston (3) is provided with a front action surface (31), and the rear end of the piston (3) is provided with a rear action surface (32); The action area of ​​the front action surface (31) is smaller than the action area of ​​the rear action surface (32); The ratio of the effective area of ​​the front effective surface (31) to the effective area of ​​the rear effective surface (32) is substantially 1:3; The movement process of the piston (3) includes a return movement, and the return movement includes a return acceleration stage and a return braking stage. The stroke of the piston (3) in the return acceleration stage is L1, and the return braking distance is X, wherein L1≥2X; The set stroke of the piston (3) before entering the rear braking chamber (223) is L2, wherein L2≥2L1; The axial length of the braking rear chamber (223) is L5, wherein X>L5; The movement process of the piston (3) includes a stroke movement, and the piston (3) is preset with a first safety distance L3 during the stroke movement, wherein the first safety distance is the distance before the piston (3) hits and enters the brake front chamber (213), wherein L3 is greater than the normal drilling amount of the rock drill; The piston (3) is preset with a second safety distance L4 during the stroke movement, wherein the second safety distance is the axial length of the brake front chamber (213), wherein L4>L3.

2. The impact structure for a rock drill according to claim 1, characterized in that: The oil passage of the piston front chamber (21) comprises a front chamber oil inlet passage (211) and a front chamber oil return passage (212), and the front chamber oil inlet passage (211) is always connected; The oil passage of the piston rear chamber (22) comprises a rear chamber oil inlet passage (221) and a rear chamber oil return passage (222); The front chamber oil inlet oil passage (211), the front chamber oil return oil passage (212), the rear chamber oil return oil passage (222), and the rear chamber oil inlet oil passage (221) are arranged in sequence along the axial direction of the piston (3).

3. The impact structure for a rock drill according to claim 2, characterized in that: The piston front chamber (21) is provided with a braking front chamber (213) for braking the stroke of the piston (3).

4. The impact structure for a rock drill according to claim 3, characterized in that: The cylinder sleeve assembly (2) is also provided with a signal judgment oil circuit (23), and the signal judgment oil circuit (23) is divided into a piston judgment oil circuit (231) and an oil distribution valve judgment oil circuit (232); The piston judgment oil circuit (231) is arranged between the front chamber oil inlet oil circuit (211) and the front chamber oil return oil circuit (212); The oil distribution valve determination oil circuit (232) is arranged between the rear chamber oil return oil circuit (222) and the rear chamber oil inlet oil circuit (221).

5. The impact structure for a rock drill according to claim 4, characterized in that: The cylinder sleeve assembly (2) is provided with an oil distribution valve cavity (24) for installing the oil distribution valve (1); A valve brake chamber (241) is provided in the oil distribution valve chamber (24), and the valve brake chamber (241) is used to brake the oil distribution valve (1); A valve oil return oil circuit (242) is provided in the oil distribution valve chamber (24), and the valve oil return oil circuit (242) is communicated with the valve brake chamber (241); The valve oil return oil circuit (242) is arranged between the oil distribution valve judgment oil circuit (232) and the rear chamber oil inlet oil circuit (221).

6. The impact structure for a rock drill according to claim 1, characterized in that: Bushings (4) are respectively sleeved on the front and rear ends of the piston (3). Lubricating oil passages (41) are provided on the front and rear ends of the piston (3). The lubricating oil passages (41) are used to prevent dry grinding between the piston (3) and the bushing (4).

7. A rock drill, characterized in that: The rock drill comprises the impact structure for the rock drill according to any one of claims 1 to 6.

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