Drill bit buffer device and hydraulic rock drill

Abstract

The present invention discloses a drill bit buffer device, comprising a coaxially arranged buffer piston, a piston sleeve and a lower cylinder body, wherein the piston sleeve is sleeved on the front end of the buffer piston, and the lower cylinder body is sleeved on the rear end of the buffer piston, and a distribution housing is sleeved on the outer periphery of the piston sleeve and the lower cylinder body, and the impact piston passes through the lower cylinder body and the piston sleeve in sequence along the axial direction and is connected to the drill tail, and the drill tail can be abutted against the buffer piston, and an annular buffer groove is provided on the inner peripheral side of the lower cylinder body, and the buffer groove is connected to the high-pressure channel, and a throttling section is provided at the rear end of the buffer piston, and the diameter of the throttling section gradually decreases from front to back along the axial direction. A variable cross-section throttling design is adopted to achieve a smooth buffering braking effect, avoid premature damage to the connecting screws, and improve the overall reliability of the rock drill. The present invention also discloses a hydraulic rock drill including the above-mentioned drill bit buffer device.

Description

Technical Field

[0001] The present invention relates to the field of rock drilling equipment, in particular to a drill bit buffer device. In addition, the present invention also relates to a hydraulic rock drill comprising the drill bit buffer device. Background Art

[0002] The hydraulic rock drill is an important hydraulic basic component in modern tunnel excavation and mining. It uses a reversing valve and an impact piston to form a stroke feedback system, which produces oil channel switching, so that the hydraulic oil drives the impact piston to continuously impact the drill tail, generating impact stress, which is transmitted to the interface between the drill bit and the rock to produce a rock breaking effect.

[0003] To cushion the energy and force of the drill bit's rebound, most existing hydraulic rock drills are designed with a buffer system. High-power hydraulic rock drills with high rebound energy utilize a hydraulic buffer system. The vast majority of hydraulic rock drills are designed with a secondary buffer. Typically, the secondary buffer chamber and the second buffer portion of the buffer piston form a closed chamber, creating a high pressure peak and exerting a significant braking force on the piston. When the buffer piston completes braking and moves toward the drill bit, the secondary buffer chamber and the second buffer portion of the buffer piston form a closed chamber. If sufficient hydraulic oil is not supplied in a timely manner, a vacuum forms within the closed chamber, causing cavitation within the closed chamber. The hydraulic shock force generated by the instantaneous pressure fluctuations in the secondary buffer ultimately acts on the rock drill's connecting screws, causing them to loosen and deform, impacting the rock drill's reliability.

[0004] Therefore, how to provide a drill bit buffer device with stable buffering is a technical problem that those skilled in the art currently need to solve. Summary of the Invention

[0005] The present invention aims to provide a drill bit buffer device that utilizes a variable cross-section throttling design to achieve a smooth, buffered braking effect, prevent premature damage to the connecting screws, and improve the overall reliability of the rock drill. Another object of the present invention is to provide a hydraulic rock drill that includes the aforementioned drill bit buffer device.

[0006] In order to solve the above technical problems, the present invention provides a drill bit buffer device, comprising a coaxially arranged buffer piston, a piston sleeve and a lower cylinder body, wherein the piston sleeve is sleeved on the front end of the buffer piston, and the lower cylinder body is sleeved on the rear end of the buffer piston. A distribution housing is sleeved on the outer periphery of the piston sleeve and the lower cylinder body, and the impact piston passes through the lower cylinder body and the piston sleeve in sequence along the axial direction and is connected to a drill tail, and the drill tail can abut against the buffer piston. An annular buffer groove is provided on the inner peripheral side of the lower cylinder body, and the buffer groove is connected to a high-pressure channel. A throttling section is provided at the rear end of the buffer piston, and the diameter of the throttling section gradually decreases from front to back along the axial direction.

[0007] When the impact piston moves in a stroke, the rear edge of the buffer groove and the outer peripheral surface of the throttling section form an annular channel, the annular channel connects the buffer groove and the rear end cavity of the lower cylinder body, and the high-pressure oil enters the rear end cavity of the lower cylinder body to push the buffer piston forward;

[0008] When the impact piston moves back, the width of the annular channel gradually decreases until the outer peripheral side of the buffer piston completely blocks the buffer groove, isolating and sealing the rear end cavity of the lower cylinder body to brake the buffer piston by holding pressure.

[0009] Preferably, an annular fluid exchange groove is provided on the inner peripheral side of the piston sleeve, the fluid exchange groove is connected to the low-pressure channel, and a fluid exchange channel is provided in the buffer piston, the front end opening of the fluid exchange channel is located on the outer peripheral side of the buffer piston, and the rear end opening of the fluid exchange channel is connected to the rear end cavity of the lower cylinder body;

[0010] When the impact piston moves in a stroke, the front end opening of the fluid exchange channel is connected to the fluid exchange tank. When the impact piston moves back to the end point, the inner peripheral side surface of the buffer piston completely blocks the front end opening of the fluid exchange channel.

[0011] Preferably, a throttling groove is provided on the throttling section.

[0012] Preferably, the high-pressure channel and the low-pressure channel are arranged on the side of the distribution housing, and the inner side of the distribution housing is provided with two annular grooves respectively communicating with the high-pressure channel and the low-pressure channel.

[0013] Preferably, a back-stop sleeve is sleeved on the outer periphery of the front end of the impact piston, and the back-stop sleeve is respectively abutted against the rear end of the shank tail and the front end of the buffer piston.

[0014] Preferably, an annular boss is provided in the middle of the outer peripheral side surface of the buffer piston, the annular boss separates the front end cavity and the rear end cavity of the piston sleeve, the front end cavity of the piston sleeve is connected to the low-pressure channel, and the rear end cavity of the piston sleeve is connected to the high-pressure channel. A drag reduction channel is provided in the buffer piston, the front end opening of the drag reduction channel is connected to the front end cavity of the piston sleeve, and the rear end opening of the drag reduction channel is located on the outer peripheral side surface of the buffer piston and behind the annular boss;

[0015] During the return movement of the impact piston, the rear end opening of the drag reduction channel is connected to the rear end cavity of the piston sleeve. When the impact piston returns to the end point, the inner peripheral side surface of the lower cylinder body completely blocks the rear end opening of the drag reduction channel.

[0016] Preferably, the front end face of the annular boss is a conical surface, the rear end face of the annular boss is a plane, and the diameter of the buffer piston at the front end part of the annular boss is smaller than the diameter of the buffer piston at the rear end part of the annular boss.

[0017] Preferably, the rear end of the fluid exchange channel extends axially, the front end of the fluid exchange channel is bent outward and tilted, the rear end of the drag reduction channel extends radially, and the front end of the drag reduction channel is bent outward and tilted.

[0018] Preferably, the fluid exchange channel and the drag reduction channel are specifically damping holes, including a plurality of the fluid exchange channels and a plurality of the drag reduction channels uniformly arranged in the circumferential direction.

[0019] The present invention provides a hydraulic rock drill comprising a drill bit buffer device as described in any one of the above.

[0020] The present invention provides a drill bit buffer device, comprising a coaxially arranged buffer piston, a piston sleeve and a lower cylinder body, wherein the piston sleeve is sleeved on the front end of the buffer piston, and the lower cylinder body is sleeved on the rear end of the buffer piston, and a distribution housing is sleeved on the outer periphery of the piston sleeve and the lower cylinder body, and the impact piston sequentially passes through the lower cylinder body and the piston sleeve in the axial direction and is connected to the drill tail, and the drill tail can abut against the buffer piston, and an annular buffer groove is provided on the inner periphery side of the lower cylinder body, and the buffer groove is connected to the high-pressure channel, and a throttling section is provided on the rear end of the buffer piston, and the diameter of the throttling section gradually decreases from front to rear along the axial direction;

[0021] When the impact piston moves during the stroke, the rear edge of the buffer groove and the outer peripheral surface of the throttling section form an annular channel, which connects the buffer groove and the rear end cavity of the lower cylinder body. The high-pressure oil enters the rear end cavity of the lower cylinder body to push the buffer piston forward; when the impact piston moves during the return stroke, the width of the annular channel gradually decreases until the outer peripheral side of the buffer piston completely blocks the buffer groove, isolating and closing the rear end cavity of the lower cylinder body, thereby holding the pressure to brake the buffer piston.

[0022] The variable cross-section throttling design is adopted. When the impact piston moves back, the throttling surface gradually decreases without sudden changes, effectively avoiding impact. Until the buffer piston moves to a specific position, the rear end cavity of the closed lower cylinder is isolated and closed, and the buffer piston is braked by holding pressure, thereby achieving a smooth buffering and braking effect, avoiding premature damage to the connecting screws, and improving the overall reliability of the rock drill.

[0023] The present invention also provides a hydraulic rock drill including the above-mentioned drill bit buffer device. Since the above-mentioned drill bit buffer device has the above-mentioned technical effects, the above-mentioned hydraulic rock drill should also have the same technical effects, which will not be introduced in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A cross-sectional schematic diagram of a specific embodiment of the drill bit buffer device provided by the present invention;

[0025] Figure 2 A cross-sectional schematic diagram of a buffer piston in a specific embodiment of the drill bit buffer device provided by the present invention;

[0026] Figure 3 This is a structural schematic diagram of the buffer piston in a specific embodiment of the drill bit buffer device provided by the present invention. DETAILED DESCRIPTION

[0027] The core of the present invention is to provide a drill bit buffer device that adopts a variable cross-section throttling design to achieve a smooth buffering and braking effect, prevent premature damage to the connecting screws, and improve the overall reliability of the rock drill. Another core of the present invention is to provide a hydraulic rock drill including the drill bit buffer device.

[0028] In order to enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0029] Please refer to Figures 1 to 3 , Figure 1 A cross-sectional schematic diagram of a specific embodiment of the drill bit buffer device provided by the present invention; Figure 2 A cross-sectional schematic diagram of a buffer piston in a specific embodiment of the drill bit buffer device provided by the present invention; Figure 3 This is a structural schematic diagram of the buffer piston in a specific embodiment of the drill bit buffer device provided by the present invention.

[0030] The specific embodiment of the present invention provides a drill bit buffer device, including a coaxially arranged buffer piston 1, a piston sleeve 2 and a lower cylinder body 3. At the same time, the drill bit assembly includes a drill bit, a drill tail 6 and an impact piston 5 arranged in sequence from front to back, and the front and rear ends of each component are defined according to the above direction. The piston sleeve 2 is sleeved on the front end of the buffer piston 1, and the lower cylinder body 3 is sleeved on the rear end of the buffer piston 1, that is, the piston sleeve 2 and the lower cylinder body 3 jointly form a cavity with an open front end and a closed rear end. The buffer piston 1 is arranged in this cavity, the front end of the buffer piston 1 extends out, and the rear end of the buffer piston 1 is located in the cavity, and a distribution shell 4 is sleeved on the outer periphery of the piston sleeve 2 and the lower cylinder body 3. An axially penetrating through hole is provided in the middle of the buffer piston 1, and a coaxial through hole is provided at the rear end of the lower cylinder body 3. The impact piston 5 passes through the lower cylinder body 3 and the piston sleeve 2 in sequence along the axial direction and is connected to the drill tail 6, and the drill tail 6 can be abutted against the buffer piston 1. Specifically, a back-off sleeve 7 can be sleeved on the outer periphery of the front end of the impact piston 5, and the back-off sleeve 7 abuts against the rear end of the drill tail 6 and the front end of the buffer piston 1 respectively.

[0031] Among them, an annular buffer groove 31 is provided on the inner peripheral side of the lower cylinder body 3, the buffer groove 31 is connected to the high-pressure channel 41 of the system, and a throttling section 11 is provided at the rear end of the buffer piston 1. The diameter of the throttling section 11 gradually decreases from front to back along the axial direction, and the diameter of the throttling section 11 is reasonably designed so that the diameter of the thickest position at the front end can completely fit the inner wall of the lower cylinder body 3 to achieve a sealing effect.

[0032] During operation, the system pushes the impact piston 5 to move forward and perform a stroke motion. The impact piston 5 pushes the drill tail 6 forward, and the high-pressure oil in the high-pressure channel 41 pushes the buffer piston 1 forward, so that the thinner position of the throttling section 11 is aligned with the buffer groove 31. The buffer groove 31 is in an open state, and the rear edge of the buffer groove 31 and the outer peripheral surface of the throttling section 11 form an annular channel. The annular channel connects the buffer groove 31 and the rear end cavity of the lower cylinder body 3. The high-pressure oil enters the rear end cavity of the lower cylinder body 3 and pushes the rear end of the buffer piston 1, causing the buffer piston 1 to move forward.

[0033] When the rebound force transmitted by the drill bit causes the drill tail 6 to push the stop sleeve 7 to press on the buffer piston 1, it also pushes the impact piston 5 to make a return motion backward. During the backward movement of the buffer piston 1, the width of the annular channel gradually decreases until the thickest position at the front end of the throttling section 11 is aligned with the buffer groove 31, so that the outer peripheral side of the buffer piston 1 completely blocks the buffer groove 31, isolating and closing the rear end cavity of the lower cylinder body 3, forming a pressure-holding braking buffer piston 1.

[0034] When the impact piston 5 moves in a stroke, the rear edge of the buffer groove 31 and the outer peripheral surface of the throttling section 11 form an annular channel, and the annular channel connects the buffer groove 31 and the rear end cavity of the lower cylinder body 3. The high-pressure oil enters the rear end cavity of the lower cylinder body 3 to push the buffer piston 1 to move forward; when the impact piston 5 moves in a return stroke, the width of the annular channel gradually decreases until the outer peripheral side of the buffer piston 1 completely blocks the buffer groove 31, isolating and closing the rear end cavity of the lower cylinder body 3, that is, the pressure in the rear end cavity of the lower cylinder body 3 gradually increases until a closed cavity is formed and the pressure reaches the maximum value, thereby holding the pressure to brake the buffer piston 1.

[0035] The variable cross-section throttling design is adopted. When the impact piston 5 moves back, the throttling surface gradually decreases without sudden changes, effectively avoiding impact, until the buffer piston 1 moves to a specific position, isolating and closing the rear end cavity of the lower cylinder 3, and braking the buffer piston 1 with pressure, thereby achieving a smooth buffering braking effect, avoiding premature damage to the connecting screws, and improving the overall reliability of the rock drill.

[0036] Furthermore, an annular fluid exchange groove 21 is provided on the inner peripheral side of the piston sleeve 2, and the fluid exchange groove 21 is connected to the low-pressure channel 42. A fluid exchange channel 12 is provided in the buffer piston 1, and the front end opening of the fluid exchange channel 12 is located on the outer peripheral side of the buffer piston 1, and the rear end opening of the fluid exchange channel 12 is connected to the rear end cavity of the lower cylinder body 3.

[0037] When the impact piston 5 moves back to the end point, that is, when the brake buffer piston 1 is under pressure, the fluid exchange tank 21 is completely offset from the front end opening of the fluid exchange channel 12, so that the front end opening of the fluid exchange channel 12 is located on the outer peripheral side of the buffer piston 1, and the entire fluid exchange channel 12 is closed to ensure that the hydraulic oil in the rear end cavity of the lower cylinder body 3 will not flow out.

[0038] When the impact piston 5 moves in a stroke, the buffer piston 1 aligns the front end opening of the fluid exchange channel 12 with and connects to the fluid exchange tank 21, that is, the high-pressure channel 41, the buffer tank 31, the rear end cavity of the lower cylinder body 3, the fluid exchange channel 12, the fluid exchange tank 21 and the low-pressure channel 42 form a complete circuit, and the rear end cavity of the lower cylinder body 3 is discharged from the low-pressure channel 42. The hydraulic oil will be replaced once in each buffer braking cycle action, thereby playing a cooling role, ensuring that the oil will not deteriorate due to excessive temperature generated by frequent compression, nor will it increase the probability of cavitation due to the reduction of oil viscosity due to excessive temperature, thereby effectively avoiding the occurrence of cavitation.

[0039] In the drill bit buffer device provided in the specific embodiment of the present invention, a throttling groove is provided on the throttling section 11, thereby realizing a design of variable throttling as the buffer piston 1 moves axially, or a throttling groove with a conical chamfer or a variable flow area can be designed.

[0040] Among them, the high-pressure channel 41 and the low-pressure channel 42 are arranged on the side of the distribution shell 4, and the inner side of the distribution shell 4 is provided with two annular grooves respectively connecting the high-pressure channel 41 and the low-pressure channel 42, which are respectively connected to the buffer tank 31 and the liquid exchange tank 21.

[0041] On the basis of the drill bit buffer device provided in each of the above-mentioned specific embodiments, an annular boss 13 is provided in the middle of the outer peripheral side of the buffer piston 1. The annular boss 13 separates the front end cavity and the rear end cavity of the piston sleeve 2. The front end cavity of the piston sleeve 2 is connected to the low-pressure channel 42, and the rear end cavity of the piston sleeve 2 is connected to the high-pressure channel. A drag reduction channel 14 is provided in the buffer piston 1. The front end opening of the drag reduction channel 14 is connected to the front end cavity of the piston sleeve 2. The rear end opening of the drag reduction channel 14 is located on the outer peripheral side of the buffer piston 1 and behind the annular boss 13.

[0042] During the return stroke of the impact piston 5, the rear opening of the drag reduction channel 14 connects to the rear cavity of the piston sleeve 2, forming a complete hydraulic circuit consisting of the high-pressure channel 41, the rear cavity of the piston sleeve 2, the drag reduction channel 14, the front cavity of the piston sleeve 2, and the low-pressure channel 42. Some of the high-pressure oil that propels the buffer piston 1 forward is released through the drag reduction channel 14, minimizing the resistance to the balanced rebound motion of the buffer piston 1. When the impact piston 5 reaches the end of its return stroke, the inner circumferential side surface of the lower cylinder body 3 completely blocks the rear opening of the drag reduction channel 14, isolating the rear and front cavities of the piston sleeve 2. This instantly generates a forward force acting on the buffer piston 1, which keeps the drill bit pressed against the rock wall, ensuring the efficient transmission of impact power and the reliability of the rock drill.

[0043] Specifically, the front end face of the annular boss 13 is a conical surface, the rear end face of the annular boss 13 is a plane, the diameter of the buffer piston 1 at the front end part of the annular boss 13 is smaller than the diameter of the buffer piston 1 at the rear end part of the annular boss 13, or the structure and size of each component are adjusted according to the situation, which is within the scope of protection of the present invention.

[0044] Furthermore, the rear end of the fluid exchange channel 12 extends axially, the front end of the fluid exchange channel 12 is bent outward and tilted, the rear end of the drag reduction channel 14 extends radially, and the front end of the drag reduction channel 14 is bent outward and tilted, so as to ensure that the opening positions of each channel are correct and do not interfere with each other.

[0045] The fluid exchange channel 12 and the drag reduction channel 14 are specifically damping holes, and a plurality of fluid exchange channels 12 and a plurality of drag reduction channels 14 may be evenly arranged circumferentially.

[0046] In addition to the above-mentioned drill bit buffer device, a specific embodiment of the present invention further provides a hydraulic rock drill including the above-mentioned drill bit buffer device. For the structures of other parts of the hydraulic rock drill, please refer to the prior art and will not be described in detail herein.

[0047] The drill bit buffer device and hydraulic rock drill provided by the present invention have been described in detail above. This article uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above examples is intended only to facilitate understanding of the method and core concept of the present invention. It should be noted that those skilled in the art may make various improvements and modifications to the present invention without departing from the principles of the present invention, and such improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A drill bit buffer device, characterized in that: The invention comprises a coaxially arranged buffer piston (1), a piston sleeve (2) and a lower cylinder body (3), wherein the piston sleeve (2) is sleeved on the front end of the buffer piston (1), and the lower cylinder body (3) is sleeved on the rear end of the buffer piston (1); a distribution shell (4) is sleeved on the outer periphery of the piston sleeve (2) and the lower cylinder body (3); an impact piston (5) passes through the lower cylinder body (3) and the piston sleeve (2) in sequence along the axial direction and is connected to a shank (6), and the shank (6) can abut against the buffer piston (1); an annular buffer groove (31) is provided on the inner peripheral side surface of the lower cylinder body (3), and the buffer groove (31) is connected to a high-pressure channel (41); a throttling section (11) is provided at the rear end of the buffer piston (1), and the diameter of the throttling section (11) gradually decreases from front to back along the axial direction; When the impact piston (5) moves in a stroke, the rear edge of the buffer groove (31) and the outer peripheral surface of the throttling section (11) form an annular channel, and the annular channel communicates with the buffer groove (31) and the rear end cavity of the lower cylinder (3). High-pressure oil enters the rear end cavity of the lower cylinder (3) to push the buffer piston (1) forward; When the impact piston (5) moves back, the width of the annular channel gradually decreases until the outer peripheral side of the buffer piston (1) completely blocks the buffer groove (31), isolating and sealing the rear end cavity of the lower cylinder (3), thereby holding down the pressure and braking the buffer piston (1); An annular liquid exchange groove (21) is provided on the inner peripheral side of the piston sleeve (2), and the liquid exchange groove (21) is connected to the low-pressure channel (42). A liquid exchange channel (12) is provided in the buffer piston (1), and the front end opening of the liquid exchange channel (12) is located on the outer peripheral side of the buffer piston (1), and the rear end opening of the liquid exchange channel (12) is connected to the rear end cavity of the lower cylinder body (3); When the impact piston (5) moves in a stroke, the front end opening of the fluid exchange channel (12) is connected to the fluid exchange tank (21); when the impact piston (5) moves back to the end point, the inner peripheral side surface of the buffer piston (1) completely blocks the front end opening of the fluid exchange channel (12); An annular boss (13) is provided in the middle of the outer peripheral side surface of the buffer piston (1), and the annular boss (13) separates the front end cavity and the rear end cavity of the piston sleeve (2), the front end cavity of the piston sleeve (2) is connected to the low-pressure channel (42), and the rear end cavity of the piston sleeve (2) is connected to the high-pressure channel (41), and a drag reduction channel (14) is provided in the buffer piston (1), the front end opening of the drag reduction channel (14) is connected to the front end cavity of the piston sleeve (2), and the rear end opening of the drag reduction channel (14) is located on the outer peripheral side surface of the buffer piston (1) and behind the annular boss (13); During the return movement of the impact piston (5), the rear end opening of the drag reduction channel (14) is connected to the rear end cavity of the piston sleeve (2); when the impact piston (5) returns to the end point, the inner peripheral side surface of the lower cylinder body (3) completely blocks the rear end opening of the drag reduction channel (14).

2. The drill bit buffer device according to claim 1, characterized in that: The throttling section (11) is provided with a throttling groove.

3. The drill bit buffer device according to claim 2, characterized in that: The high-pressure channel (41) and the low-pressure channel (42) are arranged on the side of the distribution housing (4), and the inner side of the distribution housing (4) is provided with two annular grooves respectively communicating with the high-pressure channel (41) and the low-pressure channel (42).

4. The drill bit buffer device according to claim 1, characterized in that: A backstop sleeve (7) is sleeved on the outer periphery of the front end of the impact piston (5), and the backstop sleeve (7) is respectively abutted against the rear end of the drill tail (6) and the front end of the buffer piston (1).

5. The drill bit buffer device according to claim 1, characterized in that: The front end surface of the annular boss (13) is a conical surface, the rear end surface of the annular boss (13) is a plane, and the diameter of the buffer piston (1) at the front end portion of the annular boss (13) is smaller than the diameter of the buffer piston (1) at the rear end portion of the annular boss (13).

6. The drill bit buffer device according to claim 5, characterized in that: The rear end of the fluid exchange channel (12) extends axially, and the front end of the fluid exchange channel (12) is bent outward and tilted. The rear end of the drag reduction channel (14) extends radially, and the front end of the drag reduction channel (14) is bent outward and tilted.

7. The drill bit buffer device according to claim 6, characterized in that: The fluid exchange channel (12) and the drag reduction channel (14) are specifically damping holes, comprising a plurality of the fluid exchange channels (12) and a plurality of the drag reduction channels (14) uniformly arranged in the circumferential direction.

8. A hydraulic rock drill, characterized in that: The drill bit buffer device comprises the drill bit buffer device according to any one of claims 1 to 7.

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