Buffer device and rock drill

Abstract

The buffer device comprises a shell and a buffer piston, the shell is provided with a first-stage buffer cavity, a second-stage buffer cavity, a high-pressure oil way and a pressure relief oil way, and the high-pressure oil way is normally communicated with the first-stage buffer cavity; the buffer piston is coaxially arranged in the shell in a sliding manner and is provided with a pressure relief oil duct and a balance oil duct; the first-stage buffer cavity communicates with the pressure relief oil way through a pressure relief oil way so that pressure relief can be conducted on oil in the first-stage buffer cavity. And the first-stage buffer cavity is communicated with the second-stage buffer cavity through a balance oil duct so as to balance the oil pressure in the second-stage buffer cavity. The second aspect provides a rock drill which comprises a buffering device in the first aspect and further comprises an impact piston coaxially arranged in a buffering piston in a sliding mode. The bit shank is coaxially arranged on the front side of the impact piston; and the buffering spacer bush is sleeved on the impact piston and is positioned between the buffering piston and the bit shank. The buffering device adopts a graded buffering braking mode, different buffering requirements can be met, self-balancing regulation and control can be carried out, and the buffering effect is improved.

Description

Technical Field

[0001] This application relates to the field of rock drill technology, specifically to a buffer device and a rock drill. Background Technology

[0002] Rock drilling rigs are widely used in various working conditions such as rock mining and tunnel excavation. As a key core component of the rig, hydraulic rock drills have become the preferred choice for rock drilling equipment due to their high efficiency and environmental friendliness, which also places higher demands on the design of rock drills. During rock drilling operations, energy rebound is inevitable. This rebound force is transmitted to the inside of the rock drill in the form of waves through the drill bit, which can easily cause damage to the internal components of the rock drill and increase the consumption of drill bit components.

[0003] In the prior art, a buffer device is installed inside the rock drill to absorb rebound energy, thereby achieving a buffering effect. Specifically, in the prior art, a closed buffer chamber is set between the buffer piston and the cylinder liner for buffering. The hydraulic oil in the buffer chamber flows only through the movement of the buffer piston. It cannot achieve self-balancing regulation according to the operating conditions, cannot adapt to the changing buffering needs, has poor adaptability, and poor buffering effect.

[0004] Therefore, there is room for further improvement in the buffer devices of existing rock drills. Utility Model Content

[0005] In view of this, in response to the technical problem of poor self-balancing control force of the buffer structure of the rock drill in the prior art, which leads to poor buffering effect, this application provides a buffer device and a rock drill. The buffer device adopts a graded buffer braking method, which can adapt to different buffering needs, and is equipped with a balancing oil passage, which can improve the pressure fluctuation characteristics of the buffer chamber, realize self-balancing control, and improve the buffering effect.

[0006] First aspect

[0007] This application provides a buffer device for use in a rock drill, comprising:

[0008] The housing is provided with a primary buffer chamber, a secondary buffer chamber, a high-pressure oil circuit, and a pressure relief oil circuit, wherein the high-pressure oil circuit is normally connected to the primary buffer chamber;

[0009] The buffer piston is coaxially slidably disposed within the housing, and is provided with a pressure relief oil passage and a balance oil passage;

[0010] The primary buffer chamber is connected to the pressure relief oil circuit through a pressure relief oil passage for relieving pressure on the oil in the primary buffer chamber.

[0011] The primary buffer chamber and the secondary buffer chamber are connected by a balancing oil passage to balance the oil pressure in the secondary buffer chamber.

[0012] Compared with the prior art, in the buffer device of this application, the high-pressure oil circuit is always connected to the primary buffer chamber, and the high-pressure oil circuit can continuously supply high-pressure oil into the primary buffer chamber. During the axial displacement of the buffer piston, the connection between the primary buffer chamber and the pressure relief oil circuit can be changed, enabling pressure relief and pressurization of the primary buffer chamber, achieving effective buffering and playing a primary buffering role. Simultaneously, during the axial displacement of the buffer piston, the connection between the secondary buffer chamber and the primary buffer chamber can be changed. The secondary buffer chamber can store oil, playing a secondary buffering role on one hand, and balancing the oil pressure in the secondary buffer chamber on the other hand, ensuring... The system ensures rapid replenishment of oil in the secondary buffer chamber. Furthermore, the balancing oil passage, in conjunction with the primary and secondary buffer chambers, not only achieves self-balancing regulation but also improves the pressure fluctuation characteristics of the secondary buffer chamber, reduces the acceleration during the buffer piston reset process, avoids the impact force during piston reset, and reduces the duration of negative pressure in the secondary buffer chamber, thus lowering the risk of cavitation. This application, through the coordination of the pressure relief oil passage, balancing oil passage, pressure relief oil circuit, buffer chamber, and high-pressure oil circuit, achieves graded braking, improving the buffering effect and thus providing effective self-balancing regulation. This allows it to adapt to the buffering braking needs of more models under different operating conditions.

[0013] Preferably, the primary buffer chamber and the secondary buffer chamber are distributed along the axial direction, with the primary buffer chamber located in front of the secondary buffer chamber;

[0014] The buffer piston is provided with a first working surface and a second working surface. The first working surface overlaps with the projection of the primary buffer chamber on the central axis, and the second working surface overlaps with the projection of the secondary buffer chamber on the central axis.

[0015] In this embodiment, the first working surface and the second working surface are respectively disposed at the primary buffer chamber and the secondary buffer chamber, in order to enhance the graded buffering braking effect of the buffer piston.

[0016] Preferably, the projections of the first and second working surfaces on the same radial line do not overlap, and the working area of ​​the second working surface is greater than the working area of ​​the first working surface.

[0017] The first working surface is inclined to the central axis, and the second working surface is perpendicular to the central axis;

[0018] The distance between the primary buffer chamber and the central axis of the shell is greater than the distance between the secondary buffer chamber and the central axis of the shell.

[0019] The pressure relief oil passages are spaced in front of the balance oil passages, and the pressure relief oil circuits are spaced in front of the high pressure oil circuits.

[0020] In this embodiment, by rationally setting the positions of the two buffer chambers, the pressure relief oil passage, the balance oil passage, the pressure relief oil circuit, and the high-pressure oil circuit, it is possible to achieve graded buffer braking, and the secondary buffer braking effect can be greater, which can avoid the impact of the rear side of the buffer piston as much as possible and absorb the rebound force of the drill bit as much as possible.

[0021] Preferably, the pressure relief oil passage includes a first oil passage and a second oil passage, and the ends of the first oil passage and the second oil passage away from the housing are connected;

[0022] The first oil passage is located in front of the second oil passage, and there is an angle between the first oil passage and the second oil passage;

[0023] The angle between the first oil passage and the radial parallel line is θ1, and the angle between the second oil passage and the radial parallel line is θ2, where θ1>θ2.

[0024] In this embodiment, by reasonably setting the structure of the pressure relief oil passage, the slope of the second oil passage connected to the first-stage buffer chamber can be steeper, so that the oil in the first-stage buffer chamber can flow into the pressure relief oil passage more quickly, thereby accelerating the buffer response.

[0025] Preferably, the balancing oil passage includes a third oil passage and a fourth oil passage, and the ends of the third oil passage and the fourth oil passage that are away from the housing are connected;

[0026] The third oil passage is located in front of the fourth oil passage, and there is an angle between the third oil passage and the fourth oil passage;

[0027] The angle between the third oil passage and the radial parallel line is θ3, and the angle between the fourth oil passage and the radial parallel line is θ4, where θ4>θ3.

[0028] In this embodiment, by rationally setting the structure of the balance oil passage, the slope of the third oil passage connected to the first-stage buffer chamber can be made steeper, so that the oil in the first-stage buffer chamber can flow to the second-stage buffer chamber more quickly, thereby accelerating the buffer response and braking response.

[0029] Preferably, it further includes a rear braking chamber, which is located at the rear end of the buffer piston, and the braking stroke of the buffer piston in the rear braking chamber is less than the axial length X of the rear braking chamber;

[0030] When the buffer piston is at its front limit position:

[0031] The pressure relief oil passage is located between the first oil passage and the second oil passage, the high pressure oil passage is located between the second oil passage and the third oil passage, the third oil passage is connected to the primary buffer chamber, and the fourth oil passage is connected to the secondary buffer chamber.

[0032] The distance between the first oil passage and the pressure relief oil passage is less than X, and the distance between the third oil passage and the front end of the secondary buffer chamber is less than X.

[0033] In this embodiment, through the above-mentioned reasonable settings, the buffer piston can be moved to a certain node, which can ensure that the pressure relief oil passage and the balance oil passage are simultaneously connected to the first-stage buffer chamber, so as to achieve the effect of second-stage buffer braking.

[0034] Preferably, the movement of the buffer piston includes a stroke and a return stroke;

[0035] The return motion includes:

[0036] In the first stage, the buffer piston moves backward to connect with the primary buffer chamber and the pressure relief oil circuit;

[0037] In the second stage, the buffer piston moves backward until the primary buffer chamber and the secondary buffer chamber are disconnected;

[0038] In the third stage, the buffer piston moves backward until the primary buffer chamber is disconnected from the pressure relief oil circuit;

[0039] In the fourth stage, the buffer piston moves backward until its velocity reaches 0.

[0040] The stroke includes:

[0041] In the first stage, the buffer piston moves forward to connect with the primary buffer chamber and the pressure relief oil circuit.

[0042] In the second stage, the buffer piston moves forward until the primary buffer chamber and the secondary buffer chamber are connected.

[0043] In the third stage, the buffer piston moves forward until the primary buffer chamber is disconnected from the pressure relief oil circuit;

[0044] In the fourth stage, the buffer piston moves forward to its front limit position.

[0045] In this embodiment, the buffer piston can exhibit the effects of two-stage buffer braking and self-balancing regulation during both its stroke and return, greatly improving the buffering effect.

[0046] Preferably, the buffer piston is provided with a pressure equalization groove, the pressure equalization groove is arranged along the outer periphery of the buffer piston, and the pressure equalization groove is recessed toward the center of the buffer piston;

[0047] Multiple equalizing grooves are provided, and these grooves are distributed at intervals along the axial direction.

[0048] In this embodiment, by setting an equalizing groove, the eccentricity of the buffer piston caused by its own weight and other factors can be effectively reduced, thereby effectively preventing the buffer piston from dry grinding.

[0049] Preferably, the buffer piston is provided with an air inlet groove and a lubrication groove, and the air inlet groove and the lubrication groove are arranged on the end face of the buffer piston facing the shank.

[0050] The air intake groove is arranged radially, the lubrication groove is arranged circumferentially, and the air intake groove and the lubrication groove are connected.

[0051] In this embodiment, the air inlet groove and lubrication groove can ensure that the front side of the buffer piston receives sufficient lubricating air, reduce the probability of dry friction, and increase the service life of the buffer piston.

[0052] Secondly, this application provides a rock drill, including the buffer device described in any embodiment provided in the first aspect, and further comprising:

[0053] The impact piston is coaxially and slidingly disposed within the buffer piston.

[0054] The drill bit is coaxially positioned on the front side of the impact piston.

[0055] The buffer sleeve is fitted onto the impact piston and is located between the buffer piston and the drill bit.

[0056] In this embodiment, the rock drill's impact structure is equipped with a buffer device, which can buffer the rebound force in the rock drill's impact structure, reduce the impact on the internal components of the rock drill, and effectively improve the service life of the rock drill. Attached Figure Description

[0057] Figure 1 This is a partial cross-sectional structural schematic diagram of a rock drill provided in an embodiment of this application;

[0058] Figure 2 This is a cross-sectional structural schematic diagram of a buffer piston provided in an embodiment of this application;

[0059] Figure 3 This is a three-dimensional structural schematic diagram of a buffer piston provided in an embodiment of this application;

[0060] Figure 4 This is a cross-sectional schematic diagram of the motion state of a buffer piston provided in an embodiment of this application. Figure 1 ;

[0061] Figure 5 This is a cross-sectional schematic diagram of the motion state of a buffer piston provided in an embodiment of this application. Figure 2 ;

[0062] Figure 6 This is a cross-sectional schematic diagram of the motion state of a buffer piston provided in an embodiment of this application. Figure 3 ;

[0063] Figure 7 This is a cross-sectional schematic diagram of the motion state of a buffer piston provided in an embodiment of this application. Figure 4 ;

[0064] Figure 8 This is a cross-sectional schematic diagram of the motion state of a buffer piston provided in an embodiment of this application. Figure 5 ;

[0065] Figure 9 yes Figure 1 A magnified schematic diagram of part A.

[0066] Reference numerals: 1. Housing; 2. Buffer piston; 3. Impact piston; 4. Chisel tail; 5. Buffer septum; 11. Pressure relief oil passage; 12. High-pressure oil passage; 13. Primary buffer chamber; 14. Secondary buffer chamber; 15. Rear brake chamber;

[0067] 21. Pressure relief oil passage; 22. Balancing oil passage; 23. First working surface; 24. Second working surface; 25. Pressure equalizing groove; 26. Air inlet groove; 27. Lubrication groove;

[0068] 211. First oil passage; 212. Second oil passage;

[0069] 221. Third oil passage; 222. Fourth oil passage. Detailed Implementation

[0070] 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.

[0071] 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.

[0072] 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.

[0073] The present application will now be described in further detail with reference to the accompanying drawings, see below. Figures 1 to 9 illustrate.

[0074] First aspect

[0075] This application provides a buffer device applied within the impact structure of a rock drill to buffer the impact of the rock drill. This buffer effectively prevents damage to the internal components of the rock drill, thereby improving the service life of the rock drill.

[0076] Specifically, such as Figure 1 As shown, the buffer device includes a housing 1 and a buffer piston 2. The buffer piston 2 is sleeved on the outside of the impact piston 3. The buffer piston 2, the impact piston 3, and the housing 1 are coaxially arranged. The buffer piston 2 can be axially displaced relative to the housing 1. The inner side of the housing 1 is provided with two recesses that are recessed away from the buffer piston 2. The two recesses and the outer wall of the buffer piston 2 respectively form a primary buffer chamber 13 and a secondary buffer chamber 14. The housing 1 is provided with a pressure relief oil passage 11 and a high-pressure oil passage 12. The pressure relief oil passage 11 and the high-pressure oil passage 12 are distributed axially at intervals. The pressure relief oil passage 11 is located in front of the high-pressure oil passage 12, that is, the pressure relief oil passage 11 is closer to the drill bit 4. The pressure relief oil passage 11 and the high-pressure oil passage 12 are arranged radially and have openings on the inner and outer walls of the housing 1. The two are externally connected to an oil valve device. The inner wall opening of the high-pressure oil passage 12 is normally connected to the primary buffer chamber 13.

[0077] like Figures 1 to 3 As shown, the buffer piston 2 is provided with a pressure relief oil passage 21 and a balance oil passage 22, which are spaced apart along the axial direction, with the pressure relief oil passage 21 located in front of the balance oil passage 22. The end of the pressure relief oil passage 21 that connects to the primary buffer chamber 13 is always open, meaning that regardless of the displacement and direction of the buffer piston 2, the oil in the primary buffer chamber 13 can always enter the pressure relief oil passage 21. In this application, when the buffer piston 2 moves axially, the pressure relief oil passage 21 can release the oil from the primary buffer chamber 13. The oil in the chamber 13 is guided to the pressure relief oil passage 11. That is, during the displacement of the buffer piston 2, when it is displaced to the appropriate point, the other end of the pressure relief oil passage 21 can be connected to the pressure relief oil passage 11, so that the oil in the first-stage buffer chamber 13 can flow into the pressure relief oil passage 11 through the pressure relief oil passage 21, thereby realizing the pressure relief of the oil in the first-stage buffer chamber 13, and then realizing the first-stage buffer braking effect, effectively reducing the energy when the buffer piston 2 is subjected to a secondary impact, and reducing the damage to the buffer piston 2 and its mounting structure.

[0078] like Figure 9As shown, the balancing oil passage 22 is located behind the pressure relief oil passage 21, and the secondary buffer chamber 14 is located behind the primary buffer chamber 13. During the displacement of the buffer piston 2, when it reaches the appropriate point, the primary buffer chamber 13 and the secondary buffer chamber 14 can be connected through the balancing oil passage 22. The oil in the secondary buffer chamber 14 and the primary buffer chamber 13 can flow into or out of each other, allowing the secondary buffer chamber 14 to store oil. This serves as a secondary buffer and balances the oil pressure in the secondary buffer chamber 14, ensuring rapid replenishment of the oil in the secondary buffer chamber 14. In addition to self-balancing regulation, the balancing oil passage 22, in conjunction with the primary and secondary buffer chambers 13 and 14, can improve the pressure fluctuation characteristics of the secondary buffer chamber 14, reduce the acceleration during the reset process of the buffer piston 2, avoid the impact force during the reset of the buffer piston 2, and reduce the duration of negative pressure in the secondary buffer chamber 14, thus reducing the risk of cavitation. This ensures rapid replenishment of the oil in the buffer chamber, achieving a secondary buffer function while realizing self-balancing regulation.

[0079] Correspondingly, such as Figure 2 , Figure 9 As shown, the buffer piston 2 is provided with a first working surface 23 and a second working surface 24. On the projection of the central axis of the housing 1, the first-stage buffer chamber 13 overlaps with the first working surface 23, and the second-stage buffer chamber 14 overlaps with the second working surface 24. That is, the first working surface 23 is correspondingly located at the first-stage buffer chamber 13. The oil in the first-stage buffer chamber 13 acts on the first working surface 23, which can exert a forward force on the buffer piston 2, thereby assisting the buffer piston 2 to form a buffer braking. The second working surface 24 is correspondingly located at the second-stage buffer chamber 14. The oil in the second-stage buffer chamber 14 acts on the second working surface 24, which can exert a forward force on the buffer piston 2, thereby assisting the buffer piston 2 to form a buffer braking.

[0080] Furthermore, such as Figure 2 , Figure 9 As shown, the projections of the first acting surface 23 and the second acting surface 24 on the same radial line do not overlap, that is, the first acting surface 23 and the second acting surface 24 are distributed in the radial direction, thus better matching the structure of the primary buffer chamber 13 and the secondary buffer chamber 14, thereby generating force on the buffer piston 2 in two directions, presenting graded and layered braking. Furthermore, as... Figure 2 , Figure 9As shown, the distance between the front end of the first working surface 23 and the central axis is greater than the distance between the rear end and the central axis, so that the first working surface 23 is inclined to the axial parallel line. The angle between the first working surface 23 and the central axis is 8° to 12°. Setting the angle between the first working surface 23 and the central axis within this range can reduce the degree of bulging of the angle, thereby reducing the risk of local stress concentration and reducing oil energy loss. In this embodiment, the angle between the first working surface 23 and the central axis is preferably 10°.

[0081] like Figure 2 , Figure 9 As shown, in the radial direction, the distance between the primary buffer chamber 13 and the central axis of the housing 1 is greater than the distance between the secondary buffer chamber 14 and the central axis of the housing 1. The primary buffer chamber 13 and the secondary buffer chamber 14 are arranged adjacent to each other, and a step is formed between the rear side of the primary buffer chamber 13 and the front side of the secondary buffer chamber 14, so that the primary buffer chamber 13 and the secondary buffer chamber 14 form a stepped distribution. In this embodiment, the structure of the primary buffer chamber 13 and the secondary buffer chamber 14 can be well matched with the first working surface 23 and the second working surface 24, thereby realizing the layered braking effect of graded braking and improving the buffer braking effect.

[0082] like Figure 2 , Figure 9 As shown, the second working surface 24 is set perpendicular to the central axis direction. The bottom of the second working surface 24 is set as an arc-shaped structure at the connection with the buffer piston 2. The arc surface can make the stress evenly distributed along the arc surface, avoid stress concentration, improve the load-bearing capacity and durability of the second working surface 24, reduce the risk of local stress concentration when the oil in the secondary buffer chamber 14 interacts with the second working surface 24, and reduce the energy loss of the oil, so as to more effectively maintain the kinetic energy and pressure of the fluid.

[0083] like Figure 2 , Figure 9 As shown, the area of ​​the second action surface 24 is larger than that of the first action surface 23. Considering the angles of the first action surface 23 and the second action surface 24, as well as their distance from the centerline, it can be determined that the thrust generated by the oil in the first-stage buffer chamber 13 after interacting with the first action surface 23 is inclined towards the central axis, with a relatively large distance from the central axis of the buffer piston 2. Conversely, the thrust generated by the oil in the second-stage buffer chamber 14 after interacting with the second action surface 24 is almost parallel to the central axis, with a relatively small distance from the central axis of the buffer piston 2. Therefore, the braking forces of the first and second stages are different, with the second-stage braking being more effective than the first-stage braking. It can exert a greater forward force when the buffer piston 2 receives the rebound force of the drill bit 4, preventing impact at the rear end of the buffer piston 2 and thus minimizing the rebound force of the drill bit 4, preventing the rebound force from being transmitted to the internal parts of the rock drill.

[0084] In addition, in this application, since the first working surface 23 is inclined to the central axis and the second working surface 24 is provided with an arc-shaped structure, both the first-stage braking and the second-stage braking will generate a thrust on the buffer piston 2 in the direction of the central axis, thereby avoiding the buffer piston 2 from being too close to the housing 1, reducing the frictional loss between the buffer piston 2 and the housing 1, and improving the service life of the buffer piston 2 and the housing 1.

[0085] It should be noted that, as Figure 2 , Figure 9 As shown, due to the structure of the first working surface 23 and the second working surface 24, the outer diameter of the buffer piston 2 is not uniform, so that the buffer piston 2 can be roughly divided into at least five parts. The first part is located in front of the first working surface 23, the second part corresponds to the area where the first working surface 23 is located, the third part is located between the rear of the first working surface 23 and the front of the second working surface 24, the fourth part corresponds to the area where the second working surface 24 is located, and the fifth part is located behind the second working surface 24. Among them, the outer diameter of the second part and the fourth part corresponds to the structural changes of their corresponding working surfaces, that is, the outer diameter of the second part and the fourth part is not uniform. However, roughly speaking, the outer diameters of the five parts are arranged in descending order, namely the first part, the second part, the third part, the fourth part, and the fifth part.

[0086] Among them, the first oil port of the first oil passage 211 is located in the first part, the second oil port of the second oil passage 212 is located in the second part, the third oil port of the third oil passage 221 is located in the third part, and the fourth oil port of the fourth oil passage 222 is located in the fifth part; that is, each oil port is not at the same radial height.

[0087] Based on any of the above embodiments, the pressure relief oil passage 21 is further described; such as Figure 9 As shown, the pressure relief oil passage 21 includes a first oil passage 211 and a second oil passage 212. The first oil passage 211 is located in front of the second oil passage 212, and a V-shaped structure is formed between the first oil passage 211 and the second oil passage 212. The ends of the first oil passage 211 and the second oil passage 212 away from the housing 1 are connected. The end of the first oil passage 211 away from the second oil passage 212 opens on the outside of the buffer piston 2 to form a first oil port, which can communicate with the pressure relief oil passage 11. The end of the second oil passage 212 away from the first oil passage 211 opens on the outside of the buffer piston 2 to form a second oil port, which can communicate with the primary buffer chamber 13. The first oil port and the second oil port are distributed axially at intervals. There is an angle between the first oil passage 211 and the second oil passage 212, which is set between 70° and 110°. Preferably, in this embodiment, the angle between the first oil passage 211 and the second oil passage 212 is set to 78°.

[0088] In this embodiment, the first working surface 23 is located above the second oil port of the second oil passage 212. Both sides of the second oil port are the first working surface 23, but the first working surface 23 is basically located behind the second oil port.

[0089] Among them, such as Figure 2 , Figure 9 As shown, the angle between the first oil passage 211 and the radial parallel line is θ1, and the angle between the second oil passage 212 and the radial parallel line is θ2, where θ1>θ2. In this embodiment, the angle between the second oil passage 212 and the radial parallel line is smaller, that is, the inclination of the second oil passage 212 is greater. The primary buffer chamber 13 is located above the pressure relief oil passage 21. Therefore, the oil in the primary buffer chamber 13 can flow quickly into the second oil passage 212, thereby reducing the pressure in the primary buffer chamber 13 and reducing the impact when the buffer piston 2 resets.

[0090] Based on any of the above embodiments, the balance oil passage 22 will be further described; such as Figure 2 , Figure 9 As shown, the balancing oil passage 22 includes a third oil passage 221 and a fourth oil passage 222. The third oil passage 221 is located in front of the fourth oil passage 222, and a V-shaped structure is formed between the third oil passage 221 and the fourth oil passage 222. The ends of the third oil passage 221 and the fourth oil passage 222 away from the housing 1 are connected. The end of the third oil passage 221 away from the fourth oil passage 222 opens on the outside of the buffer piston 2 to form a third oil port, which can communicate with the primary buffer chamber 13. The end of the fourth oil passage 222 away from the third oil passage 221 opens on the outside of the buffer piston 2 to form a fourth oil port, which can communicate with the secondary buffer chamber 14. The third oil port and the fourth oil port are distributed axially at intervals. There is an angle between the third oil passage 221 and the fourth oil passage 222, which is set between 80° and 110°. Preferably, in this embodiment, the angle between the third oil passage 221 and the fourth oil passage 222 is set to 90°.

[0091] In this embodiment, the second working surface 24 is located between the third oil passage 221 and the fourth oil passage 222.

[0092] Among them, such as Figure 2 , Figure 9 As shown, the angle between the third oil passage 221 and the radial parallel line is θ3, and the angle between the fourth oil passage 222 and the radial parallel line is θ4, where θ4 > θ3. In this embodiment, the angle between the third oil passage 221 and the radial parallel line is smaller, that is, the inclination of the third oil passage 221 is greater. The primary buffer chamber 13 is located above the third oil passage 221. Therefore, the oil in the secondary buffer chamber 14 can flow into the third oil passage 221 quickly, thereby accelerating the connection speed between the primary buffer chamber 13 and the secondary buffer chamber 14, that is, reducing the pressure drop during the reset phase of the secondary buffer chamber 14.

[0093] Furthermore, such as Figure 1 , Figure 2 As shown, the rear end of the buffer piston 2 is provided with a braking rear chamber 15, which is formed by the housing 1 and the buffer piston 2. The braking stroke of the buffer piston 2 in the braking rear chamber 15 is less than the axial length dimension X of the braking rear chamber 15.

[0094] When the buffer piston 2 is at its front limit position: the pressure relief oil passage 11 is located between the first oil passage 211 and the second oil passage 212, the second oil passage 212 is located in the first-stage buffer chamber 13, the distance between the first oil passage 211 and the pressure relief oil passage 11 is less than X, and the distance between the second oil passage 212 and the rear end of the second-stage buffer chamber 14 is greater than X. As a result, when the buffer piston 2 moves backward, it can ensure that the first oil passage 211 will pass through the pressure relief oil passage 11, and the second oil passage 212 can always be located in the first-stage buffer chamber 13. As a result, the pressure relief oil passage 11 can be connected to the first-stage buffer chamber 13 through the pressure relief oil passage 21.

[0095] The distance between the first oil passage 211 and the front end of the first-stage buffer chamber 13 is greater than X, thereby ensuring that when the buffer piston 2 moves to the corresponding position during the backward movement, the first oil passage 211 can be disconnected from the pressure relief oil passage 11 and the first-stage buffer chamber 13.

[0096] The high-pressure oil circuit 12 is located between the second oil passage 212 and the third oil passage 221, and the high-pressure oil circuit 12 is always connected to the first-stage buffer chamber 13.

[0097] The third oil passage 221 is connected to the first-stage buffer chamber 13, and the fourth oil passage 222 is connected to the second-stage buffer chamber 14. The distance between the front end of the third oil passage 221 and the second-stage buffer chamber 14 is less than X, and the distance between the rear end of the fourth oil passage 222 and the second-stage buffer chamber 14 is less than X. This ensures that when the buffer piston 2 moves backward, the third oil passage 221 will move from the first-stage buffer oil passage to the second-stage buffer chamber 14, and the fourth oil passage 222 will move to the rear end of the second-stage buffer chamber 14, disengaging from the second-stage buffer chamber 14. This disconnects the first-stage buffer chamber 13 from the second-stage buffer chamber 14, thereby ensuring that the buffer piston 2 can achieve second-stage buffer braking.

[0098] Based on any of the above embodiments, the buffer piston 2 can be further extended; such as... Figures 2 to 3 As shown, the buffer piston 2 is provided with a pressure equalization groove 25. The pressure equalization groove 25 is a circular structure. The pressure equalization groove 25 is arranged along the outer periphery of the buffer piston 2. The pressure equalization groove 25 is recessed towards the center of the buffer piston 2. The surface of the pressure equalization groove 25 is an arc-shaped surface. There are multiple pressure equalization grooves 25, and the multiple pressure equalization grooves 25 are distributed at intervals along the axial direction.

[0099] In this embodiment, by setting up a pressure equalization groove 25, oil can enter the pressure equalization groove 25 and provide a certain support effect for the buffer piston 2, thereby effectively reducing the eccentricity of the buffer piston 2 caused by its own weight and other reasons; in addition, the oil in the pressure equalization groove 25 can act between the buffer piston 2 and the housing 1, thereby effectively preventing the buffer piston 2 from dry grinding.

[0100] Based on any of the above embodiments, the buffer piston 2 can be further extended; such as... Figures 2 to 3 As shown, the buffer piston 2 has an air inlet groove 26 and a lubrication groove 27 on the front wall facing the rod tip 4. The air inlet groove 26 is arranged radially and is recessed towards the rear end of the buffer piston 2. The air inlet groove 26 has openings on the outer and inner walls of the buffer piston 2 so that lubricating gas can be introduced from the outside.

[0101] The lubrication groove 27 is arranged circumferentially and has a circular structure. The lubrication groove 27 is recessed towards the rear end of the buffer piston 2. The inner diameter of the lubrication groove 27 is larger than the inner diameter of the buffer piston 2 and smaller than the outer diameter of the buffer piston 2, so that the air inlet groove 26 is connected to the lubrication groove 27. Then, the lubricating gas in the air inlet groove 26 can enter the lubrication groove 27, thereby increasing the lubrication area at the front end of the buffer piston 2. This ensures that the front side of the buffer piston 2 can receive sufficient lubricating gas, reduces the probability of dry friction between the front side of the buffer piston 2 and other components, and increases the service life of the buffer piston 2.

[0102] Based on any of the above embodiments, the movement process of the buffer piston 2 is further described; the movement process of the buffer piston 2 includes stroke movement and return movement;

[0103] During the return journey, such as Figures 4 to 8 As shown, the return motion, i.e., the backward movement under the action of the spring force of the buffer piston 2 and the rod tip 4, includes the following stages:

[0104] Buffer waiting phase, such as Figure 4 As shown, this stage is between the impact piston 3 striking the drill bit 4, and the buffer piston 2 is at the front limit. In this stage, the pressure relief oil passage 11 is located between the first oil passage 211 and the second oil passage 212. The first-stage buffer chamber 13 is disconnected from the pressure relief oil passage 11, and the second-stage buffer chamber 14 is connected to the first-stage buffer chamber 13.

[0105] Phase 1, such as Figure 5 As shown, in this stage, the buffer piston 2 is rebounded by the rod tail 4 and moves backward until the first oil passage 211 is connected to the pressure relief oil passage 11, that is, the first-stage buffer chamber 13 is connected to the pressure relief oil passage 11; in this stage, the first-stage buffer chamber 13 and the second-stage buffer chamber 14 are always connected, and the buffer piston 2 decelerates backward under the action of the first-stage buffer chamber 13 and the second-stage buffer chamber 14.

[0106] The second stage, such as Figure 6 As shown, based on the first stage, the buffer piston 2 continues to move backward until the primary buffer chamber 13 and the secondary buffer chamber 14 are disconnected. In this stage, since the primary buffer chamber 13 is connected to the pressure relief oil circuit 11, the pressure in the primary buffer chamber 13 and the secondary buffer chamber 14 decreases rapidly. The buffer piston 2 continues to move backward in a decelerating motion, but the absolute value of the acceleration is reduced compared to the previous stage.

[0107] The third stage, such as Figure 7 As shown, based on the second stage, the buffer piston 2 continues to move backward until the first-stage buffer chamber 13 is disconnected from the pressure relief oil circuit 11. In this stage, since the first-stage buffer chamber 13 is connected to the pressure relief oil circuit 11, the first-stage buffer chamber 13 and the second-stage buffer chamber 14 are disconnected. The pressure in the first-stage buffer chamber 13 is low, but the oil in the second-stage buffer chamber 14 is compressed due to the chamber being in a closed state, resulting in a better braking effect. This can effectively shorten the braking distance of the buffer piston 2, and the buffer piston 2 continues to move backward to decelerate.

[0108] The fourth stage, such as Figure 8 As shown, based on the third stage, the buffer piston 2 continues to move backward until the speed is 0. In this stage, the connection between the first-stage buffer chamber 13, the second-stage buffer chamber 14, and the pressure relief oil circuit 11 is completely broken. Compared with the previous stage, the pressure in the first-stage buffer chamber 13 increases rapidly. Under the action of the first-stage buffer chamber 13 and the second-stage buffer chamber 14, the buffer piston 2 decelerates backward until the speed is 0, and then begins to move forward.

[0109] In the stroke motion, such as Figures 4 to 8 As shown, the return motion, i.e., the energy absorption process of the buffer piston 2, includes the following stages:

[0110] Phase 1, such as Figure 8 , Figure 7 As shown, the buffer piston 2 moves forward until the primary buffer chamber 13 is connected to the pressure relief oil passage 11; during this stage, the buffer piston 2 moves from... Figure 8 The state moves forward to Figure 7 In this state, the connection between the primary buffer chamber 13, the secondary buffer chamber 14, and the pressure relief oil circuit 11 is completely disconnected. The buffer piston 2 accelerates forward under the action of the primary buffer chamber 13, while the secondary buffer chamber 14, being in a closed state, experiences a sudden drop in pressure, or even generates negative pressure, which hinders the buffer piston 2 from accelerating forward and reduces the forward acceleration of the buffer piston 2 to a certain extent.

[0111] The second stage, such as Figure 6As shown, based on the first stage, the buffer piston 2 continues to move forward until the primary buffer chamber 13 and the secondary buffer chamber 14 are connected. In this stage, since the primary buffer chamber 13 is connected to the pressure relief oil circuit 11, the pressure in the primary buffer chamber 13 is lower than in the previous stage. The primary buffer chamber 13 and the secondary buffer chamber 14 are still disconnected, and the secondary buffer chamber 14 is still sealed. Therefore, the forward acceleration of the buffer piston 2 is lower than in the previous stage.

[0112] The third stage, such as Figure 5 As shown, based on the second stage, the buffer piston 2 continues to move forward until the first-stage buffer chamber 13 is disconnected from the pressure relief oil passage 11. During this stage, the first-stage buffer chamber 13 and the second-stage buffer chamber 14 are always connected. The oil in the first-stage buffer chamber 13 enters the second-stage buffer chamber 14 through the balance oil passage 22, which balances the pressure in the second-stage buffer chamber 14. The resistance and acceleration effect of the oil in the second-stage buffer chamber 14 is reduced to disappear.

[0113] The fourth stage, such as Figure 4 As shown, based on the third stage, the buffer piston 2 continues to move forward until it reaches the front limit position, at which point the energy absorption motion ends and it waits for the next action.

[0114] Second aspect

[0115] This application provides a rock drill, which includes an impact piston 3, a drill bit 4, and a buffer sleeve 5, as well as a buffer device including any of the embodiments provided in the first aspect, such as... Figure 1 As shown, the impact piston 3 is coaxially slidably disposed inside the buffer piston 2; the drill bit 4 is coaxially disposed on the front side of the impact piston 3; the buffer sleeve 5 is disposed on the outside of the impact piston 3. The drill bit 4, the impact piston 3, the buffer sleeve 5 and the housing 1 are coaxially disposed. The buffer sleeve 5 is located between the buffer piston 2 and the drill bit 4. The buffer sleeve 5 plays a buffering role between the drill bit 4 and the buffer piston 2, avoiding direct dry friction between the drill bit 4 and the buffer piston 2.

[0116] The rock drill of this application has a buffer device in its impact structure, which can buffer the rebound force in the impact structure of the rock drill, reduce the impact on the internal parts of the rock drill, and effectively improve the service life of the rock drill.

[0117] 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.

[0118] 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. A damping device for use in a rock drill, characterized in that include: The housing (1) is provided with a primary buffer chamber (13), a secondary buffer chamber (14), a high-pressure oil circuit (12) and a pressure relief oil circuit (11), wherein the high-pressure oil circuit (12) is normally connected to the primary buffer chamber (13); The buffer piston (2) is coaxially slidably disposed in the housing (1), and is provided with a pressure relief oil passage (21) and a balance oil passage (22); The primary buffer chamber (13) is connected to the pressure relief oil circuit (11) through the pressure relief oil passage (21) to relieve pressure on the oil in the primary buffer chamber (13); The primary buffer chamber (13) and the secondary buffer chamber (14) are connected by a balancing oil passage (22) to balance the oil pressure in the secondary buffer chamber (14).

2. The buffer device according to claim 1, characterized in that, The primary buffer chamber (13) and the secondary buffer chamber (14) are distributed along the axial direction, with the primary buffer chamber (13) located in front of the secondary buffer chamber (14). The buffer piston (2) is provided with a first working surface (23) and a second working surface (24). The first working surface (23) overlaps with the projection of the primary buffer chamber (13) on the central axis, and the second working surface (24) overlaps with the projection of the secondary buffer chamber (14) on the central axis.

3. The buffer device according to claim 2, characterized in that, The projections of the first action surface (23) and the second action surface (24) on the same radial line do not overlap, and the action area of ​​the second action surface (24) is greater than the action area of ​​the first action surface (23). The first working surface (23) is inclined to the central axis, and the second working surface (24) is perpendicular to the central axis; The distance between the primary buffer chamber (13) and the central axis of the shell (1) is greater than the distance between the secondary buffer chamber (14) and the central axis of the shell (1); The pressure relief oil passage (21) is spaced in front of the balance oil passage (22), and the pressure relief oil passage (11) is spaced in front of the high pressure oil passage (12).

4. The buffer device according to any one of claims 1 to 3, characterized in that, The pressure relief oil passage (21) includes a first oil passage (211) and a second oil passage (212), and the first oil passage (211) and the second oil passage (212) are connected at the ends away from the housing (1); The first oil passage (211) is located in front of the second oil passage (212), and there is an angle between the first oil passage (211) and the second oil passage (212); The angle between the first oil passage (211) and the radial parallel line is θ1, and the angle between the second oil passage (212) and the radial parallel line is θ2, wherein θ1>θ2.

5. The buffer device according to claim 4, characterized in that, The balance oil passage (22) includes a third oil passage (221) and a fourth oil passage (222), and the third oil passage (221) and the fourth oil passage (222) are connected at the ends away from the housing (1); The third oil passage (221) is located in front of the fourth oil passage (222), and there is an angle between the third oil passage (221) and the fourth oil passage (222); The angle between the third oil passage (221) and the radial parallel line is θ3, and the angle between the fourth oil passage (222) and the radial parallel line is θ4, where θ4>θ3.

6. The buffer device according to claim 5, characterized in that, It also includes a rear braking chamber (15), which is located at the rear end of the buffer piston (2), and the braking stroke of the buffer piston (2) in the rear braking chamber (15) is less than the axial length X of the rear braking chamber (15); When the buffer piston (2) is at its front limit position: The pressure relief oil passage (11) is located between the first oil passage (211) and the second oil passage (212), the high pressure oil passage (12) is located between the second oil passage (212) and the third oil passage (221), the third oil passage (221) is connected to the first-stage buffer chamber (13), and the fourth oil passage (222) is connected to the second-stage buffer chamber (14). The distance between the first oil passage (211) and the pressure relief oil passage (11) is less than X, and the distance between the third oil passage (221) and the front end of the secondary buffer chamber (14) is less than X.

7. The buffer device according to claim 1, characterized in that, The movement of the buffer piston (2) includes a stroke and a return stroke. The return motion includes: In the first stage, the buffer piston (2) moves backward to the first-stage buffer chamber (13) and connects with the pressure relief oil passage (11); In the second stage, the buffer piston (2) moves backward until the primary buffer chamber (13) and the secondary buffer chamber (14) are disconnected; In the third stage, the buffer piston (2) moves backward to the first-stage buffer chamber (13) and disconnects from the pressure relief oil passage (11); In the fourth stage, the buffer piston (2) moves backward until its velocity is 0; The stroke includes: In the first stage, the buffer piston (2) moves forward to the first-stage buffer chamber (13) and connects with the pressure relief oil passage (11); In the second stage, the buffer piston (2) moves forward to connect the primary buffer chamber (13) and the secondary buffer chamber (14); In the third stage, the buffer piston (2) moves forward until the first-stage buffer chamber (13) is disconnected from the pressure relief oil circuit (11); In the fourth stage, the buffer piston (2) moves forward to the front limit position.

8. The buffer device according to claim 1, characterized in that, The buffer piston (2) is provided with a pressure equalization groove (25), which is arranged along the outer periphery of the buffer piston (2) and is recessed toward the center of the buffer piston (2); Multiple equalizing grooves (25) are provided, and the multiple equalizing grooves (25) are distributed at intervals along the axial direction.

9. The buffer device according to claim 1, characterized in that, The buffer piston (2) is provided with an air inlet groove (26) and a lubrication groove (27), and the air inlet groove (26) and the lubrication groove (27) are located on the end face of the buffer piston (2) facing the rod tip (4); The air intake groove (26) is arranged radially, the lubrication groove (27) is arranged circumferentially, and the air intake groove (26) and the lubrication groove (27) are connected.

10. A rock drill, characterized in that Including the buffer device as described in any one of claims 1 to 9, further comprising: The impact piston (3) is coaxially slidably disposed inside the buffer piston (2); The drill bit (4) is coaxially located on the front side of the impact piston (3); The buffer sleeve (5) is fitted on the impact piston (3) and located between the buffer piston (2) and the drill bit (4).

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