Hydraulic reverse impact power head

Abstract

The invention discloses a hydraulic reverse hitting impact power head which comprises a gearbox, a reverse hitting device and an impact device, and the reverse hitting device comprises a shell assembly, a drill rod and a reverse hitting piston. A control cavity is formed between the shell assembly and the reverse hitting piston, and a control oil way is further arranged in the shell assembly and the reverse hitting piston and connected with a high-pressure oil way and a low-pressure oil way in the impact device. The control cavity is used for forming a micro-pressure cavity when the power head works normally, and then the reverse hitting piston and the shell assembly are made to be close to the rear end side of the drill rod. The control cavity is further used for forming a high-pressure cavity only through communication between the control oil way and the high-pressure oil way in the process that the shell assembly drives the reverse hitting piston to move in the reverse direction to pull out the drill rod when the drill is stuck, then the reverse hitting piston is pushed to drive the drill rod to move in the reverse direction to pull out the drill rod, and the control cavity forms a micro-pressure cavity again when the drill rod is pulled out. According to the power head, the overall structure is simple and compact, oil is supplied from the interior of the impact device, automatic recognition and reverse hitting can be achieved when drill jamming occurs, and an energy accumulator does not need to be additionally installed.

Description

Technical Field

[0001] The invention relates to the technical field of rock drilling equipment, in particular to a hydraulic back-hitting impact power head. Background Art

[0002] In the current tunnel construction process, rock drilling equipment is widely used in pipe shed construction, geological forecasting, geological coring, anchor construction, grouting reinforcement, geological improvement and other operations. In view of different construction conditions, there are different requirements for parameters such as drilling diameter, depth and drilling speed. For this reason, different requirements are also put forward for the performance parameters of the power head, the core component of rock drilling equipment.

[0003] When the construction requires the power head to perform long-distance impact drilling, the complexity of objective conditions and subjective factors such as uneven rock properties, unstable drill bits themselves, low operator skills, inaccurate original data, etc. may cause the rod to get stuck. This will cause the operating hole to be scrapped and the drill rod to be left in the hole, hindering normal construction.

[0004] There are currently two ways to solve the drill bit stuck phenomenon: 1. From the perspective of preventing drill bit stuck, accurately monitor the rotary pressure. When the rotary pressure rises abnormally, the main engine hydraulic system automatically controls to stop drilling to prevent drill bit stuck; 2. From the perspective of solving drill bit stuck, the power head is equipped with a back-hitting device to impact the drill rod in the opposite direction to make the stuck drill bit and drill rod get out of the stuck point. The current solution is often to do both in parallel, setting up an anti-stuck hydraulic system on the main engine for prevention and setting up a back-hitting structure on the power head.

[0005] However, most of the reverse driving structures on the power head now require external oil supply, and manual identification of the drill bit jam is required before the reverse driving device is activated for reverse driving. Manual identification creates the possibility of misjudgment, causing the drill bit to get stuck tighter and tighter, which is ultimately difficult to resolve; at the same time, the existing reverse driving device has a large axial size and does not meet the use requirements of equipment with structural size requirements.

[0006] The invention patent with the existing patent number CN107044258A discloses a multi-frequency hydraulic rotary impact drill, including an impact mechanism, a rotation mechanism, and a back-hitting mechanism connected in sequence. The back-hitting mechanism includes a back-hitting shell connected to the front cover, a dust cover, a back-hitting piston, a back-hitting piston cylinder sleeve, and a spline shaft. When a rod jam occurs, the hydraulic oil enters the back-hitting shell and can push the back-hitting piston to move upward to support the shoulder of the spline shaft, so that the piston impacts the spline shaft to generate vibration to overcome the rod jam when pulling the rod. However, this back-hitting mechanism uses external oil supply. When a rod jam occurs, it is necessary to manually open this oil circuit to allow high-pressure oil to enter the back-hitting shell, and the rod jam cannot be automatically identified. At the same time, in order to reduce pressure fluctuations, an accumulator needs to be provided on the back-hitting mechanism, which increases the weight and complexity of the equipment and reduces the reliability of the equipment.

[0007] The utility model with the existing patent number CN207960554U discloses a hydraulic rock drill stuck drill back-strike structure, including a drill rod, a drill tail, a drill tail guide sleeve, a back-strike piston, a back-strike housing, a back-strike piston front guide sleeve, a back-strike piston rear guide sleeve, a flushing head, a front end housing, etc. During operation, when the drill rod is stuck in the rock, hydraulic oil enters the working chamber formed by the back-strike piston and the back-strike housing, and the back-strike piston is pushed by the hydraulic oil pressure, so that it has the pressure to pull out the drill rod backwards. When the back-strike piston moves backwards to open the oil leakage port inside the back-strike piston rear guide sleeve, the drill rod can be pulled out of the rock. This device has a simple structure, but it still cannot identify the stuck rod, and the oil circuit needs to be opened manually; at the same time, the axial length of this structure is too large, which will increase the axial length of the rock drill, which is not conducive to the installation of the rock drill on the propulsion beam. Summary of the invention

[0008] The present invention provides a hydraulic back-hitting impact power head to solve the technical problems that the existing back-hitting structure needs external oil supply and needs manual identification of a stuck drill before starting the back-hitting device for back-hitting, which leads to the possibility of misjudgment caused by manual identification, and the existing back-hitting device has a large axial size and does not meet the use requirements of equipment with size requirements for the structure, and in order to reduce pressure fluctuations, it is also necessary to provide an accumulator on the back-hitting mechanism, which increases the weight and complexity of the equipment and reduces the reliability of the equipment.

[0009] The technical solution adopted by the present invention is as follows:

[0010] A hydraulic back-hitting impact power head comprises: a gear box for providing rotational power, and a back-hitting device and an impact device connected to the front and rear ends of the gear box, the back-hitting device comprises a housing assembly fixed to the gear box, a drill rod axially mounted in the housing assembly, a back-hitting piston limited in the housing assembly and slidably mounted on the outer circle of the drill rod, the front end of the drill rod is connected to the drill rod, the rear end of the drill rod is connected to the power output shaft of the gear box, and the impact device is used to impact the tail end of the drill rod; a control chamber with a sealed arrangement is formed between the housing assembly and the back-hitting piston, and a control oil circuit connected to the control chamber is also provided in the housing assembly and the back-hitting piston, and the control oil circuit is respectively connected to the high pressure in the impact device The control chamber is used to connect the high-pressure oil circuit and the low-pressure oil circuit respectively through the control oil circuit to form a micro-pressure chamber when the power head is working normally, so that the back-hitting piston and the shell assembly are close to the rear end side of the drill rod, so that the back-hitting device does not work and also avoids interference with the movement of the drill rod; the control chamber is also used to automatically connect with the high-pressure oil circuit only to form a high-pressure chamber through the control oil circuit during the reverse movement of the shell assembly to pull out the drill rod under the action of external force when the drill is stuck, and then push the back-hitting piston to drive the drill rod to move in the reverse direction to pull out the drill rod, and when the drill rod is pulled out, the control chamber is re-connected with the high-pressure oil circuit and the low-pressure oil circuit through the control oil circuit to form a micro-pressure chamber.

[0011] Furthermore, the housing assembly includes a back-strike shell mounted on the outer circumference of the drill rod, and a drill rod sleeve limitedly installed in the back-strike shell; the back-strike piston is located in the back-strike shell, and the drill rod sleeve is mounted on the outer circumference of the back-strike piston, and the front end of the drill rod sleeve, the back-strike shell, and the back-strike piston are surrounded to form a control chamber, and the control oil circuit is arranged in the back-strike shell, the drill rod sleeve and the back-strike piston.

[0012] Furthermore, the outer circle of the drill rod near the gear box is convex to form a limiting step, and the rear end surface of the back-strike shell near the gear box is concavely processed to form two coaxially arranged inner and outer mounting holes; the back-strike piston is limited between the bottom of the inner mounting hole and the limiting step; the outer circle of the back-strike piston is convex to form a limiting flange, which is used to abut against the bottom of the outer mounting hole to limit the reverse movement of the back-strike shell; the drill rod sleeve is located in the outer mounting hole, and a control chamber is formed between the bottom of the outer mounting hole outside the back-strike piston and the front end surface of the drill rod sleeve.

[0013] Furthermore, the drill rod sleeve comprises a first diameter section and a second diameter section which are connected axially and have different outer diameters; the inner wall surface of the outer mounting hole has a bayonet which is engaged with the connection between the first diameter section and the second diameter section to limit the axial sliding of the drill rod sleeve.

[0014] Furthermore, the control oil circuit includes a high-pressure oil inlet hole and a low-pressure oil return hole arranged through the back-hitting housing, a first oil inlet hole and a second oil inlet hole and an oil drain hole arranged through the drill rod sleeve, and an oil guide channel arranged through the back-hitting piston; the oil inlet end of the high-pressure oil inlet hole is connected to the high-pressure oil circuit, and its opposite oil outlet ends are respectively connected to the oil inlet ends of the first oil inlet hole and the second oil inlet hole, and the oil outlet end of the first oil inlet hole is connected to the control chamber; the oil outlet end of the low-pressure oil return hole is connected to the low-pressure oil circuit, and its opposite oil inlet end is connected to the oil outlet end of the oil drain hole; the first end of the oil guide channel is connected to the control chamber, and the second end of the oil guide channel is used to connect to the oil inlet end of the oil drain hole when the power head is working normally, or to connect to the oil outlet end of the second oil inlet hole when the drill is stuck.

[0015] Furthermore, the oil guide channel is formed by connecting two intersecting oil guide holes, and at least one of the oil guide holes is a throttling hole; at least part of the length section of the first oil inlet hole in the length direction is a damping hole; at least part of the length section of the second oil inlet hole in the length direction is a damping hole.

[0016] Furthermore, the inner wall surface of the drill rod sleeve is concave to form an annular first oil collecting ring groove, which is connected to the oil inlet end of the oil drain hole; the outer ring surface of the back-hitting piston is concave to form an annular second oil collecting ring groove, which is connected to the second end of the oil guide channel; the inner wall surface of the front end of the drill rod sleeve is concave to form an annular oil guide ring groove, which is connected to the oil outlet end of the first oil inlet hole and the control chamber.

[0017] Furthermore, the housing assembly also includes a first sealing member installed between the back-hitting housing and the back-hitting piston, and a second sealing member installed between the back-hitting housing and the drill rod sleeve.

[0018] Furthermore, the hydraulic back-hitting impact power head also includes a front guide cover installed on the outer circle of the front end of the drill rod and whose rear end face abuts against the front end of the shell assembly, and a bushing limited in the front guide cover and installed on the outer circle of the front end of the drill rod, so as to ensure that the drill rod does not tilt during drilling through the bushing.

[0019] Furthermore, the hydraulic back-hitting impact power head also includes a skeleton oil seal and a retaining ring which are sequentially installed in the front guide cover along the axial direction; the skeleton oil seal and the retaining ring are also installed on the outer circle of the front end of the drill rod, and the skeleton oil seal is axially located between the retaining ring and the bushing.

[0020] The present invention has the following beneficial effects:

[0021] The hydraulic back-hitting impact power head of the present invention has a simple and compact overall structure, can effectively control its axial size, and is convenient for installation on the propulsion beam of the rock drill; at the same time, oil is supplied from the inside of the impact device, and when the drill is stuck and the external force pulls the power head other than the drill rod backward, it automatically starts to back-hit, that is, the power head of the present invention can automatically identify the stuck rod according to the movement state of the back-hitting piston, and automatically start to back-hit, when the stuck lag is released, the control oil circuit is re-connected with the high-pressure oil circuit and the low-pressure oil circuit at the same time so that the control chamber 4 is depressurized by the low-pressure oil circuit, and the power head re-enters the normal working state, without the need for manual automatic identification of the stuck rod and manual startup of the back-hitting device for back-hitting, which effectively reduces the possibility of manual misjudgment; on the other hand, in the back-hitting device of the present invention, the oil supply of the control oil circuit is the high-pressure oil circuit and the low-pressure oil circuit in the impact device arranged at the rear, and the pressure fluctuation of the hydraulic oil is absorbed by the accumulator of the impact device itself during oil supply, so there is no need to install an accumulator in the back-hitting device, thereby effectively reducing the weight and structural complexity of the back-hitting device and improving the reliability of the equipment.

[0022] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0024] Figure 1 It is a schematic diagram of the main structure of a hydraulic back-hitting impact power head according to a preferred embodiment of the present invention;

[0025] Figure 2 yes Figure 1The main structure diagram of the middle counter-attack device Figure 1 ;

[0026] Figure 3 yes Figure 2 A schematic diagram of the partially enlarged structure;

[0027] Figure 4 yes Figure 1 The main structure diagram of the middle counter-attack device Figure 2 ;

[0028] Figure 5 yes Figure 4 Schematic diagram of the partially enlarged structure.

[0029] Legend:

[0030] 1. Drill rod; 101. Limiting step;

[0031] 2. Back-stroke piston; 21. Oil guide channel; 201. Second oil collecting ring groove;

[0032] 3. Drill rod sleeve; 31. First diameter section; 32. Second diameter section; 301. First oil inlet hole; 302. Second oil inlet hole; 303. Oil drain hole; 304. First oil collecting ring groove;

[0033] 4. Reverse shell; 401. Control chamber; 402. High-pressure oil inlet hole; 403. Low-pressure oil return hole;

[0034] 5. Front guide cover; 6. Bushing; 7. Framework oil seal; 8. Retaining ring; 9. First sealing element; 10. Second sealing element. DETAILED DESCRIPTION

[0035] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0036] Reference Figure 1 , Figure 2 and Figure 4The preferred embodiment of the present invention provides a hydraulic back-hitting impact power head, comprising: a gear box for providing rotational power, and a back-hitting device and an impact device connected to the front and rear ends of the gear box, the back-hitting device comprising a housing assembly fixed to the gear box, a drill rod 1 axially mounted in the housing assembly, a back-hitting piston 2 limited in the housing assembly and slidably mounted on the outer circle of the drill rod 1, the front end of the drill rod 1 is connected to the drill rod, the rear end of the drill rod 1 is connected to the power output shaft of the gear box, and the impact device is used to impact the rear end of the drill rod 1. A control chamber 401 is formed between the housing assembly and the back-hitting piston 2, and a control oil circuit connected to the control chamber 401 is also provided in the housing assembly and the back-hitting piston 2, and the control oil circuit is respectively connected to the high-pressure oil circuit and the low-pressure oil circuit in the impact device. The control chamber 401 is used to connect the high-pressure oil circuit and the low-pressure oil circuit through the control oil circuit to form a micro-pressure chamber when the power head is working normally, so that the back-hitting piston 2 and the housing assembly are close to the rear end side of the drill rod 1, so that the back-hitting device does not work and also avoids interference with the action of the drill rod 1. The control chamber 401 is also used to form a high-pressure chamber by automatically connecting the control oil circuit only with the high-pressure oil circuit during the reverse movement of the shell assembly to pull out the drill rod 1 under the action of external force when the drill is stuck, thereby pushing the back-hitting piston 2 to drive the drill rod 1 to move in the reverse direction to pull out the drill rod, and when the drill rod is pulled out, the control chamber 401 is reconnected with the high-pressure oil circuit and the low-pressure oil circuit through the control oil circuit to form a micro-pressure chamber.

[0037] When the hydraulic back-hitting impact power head of the present invention is working, in the normal working stage: Figure 2 and Figure 3 As shown, a control chamber 401 and a control oil circuit are provided in the back-driving device, and the control oil circuit is respectively connected to the high-pressure oil circuit and the low-pressure oil circuit in the impact device. When the power head works normally, the control chamber 401 is connected to the control oil circuit, and the control oil circuit is simultaneously connected to the high-pressure oil circuit and the low-pressure oil circuit to form a circulation loop. The structural design of the control oil circuit can make the control chamber 401 form a micro-pressure chamber with a pressure slightly higher than the pressure of the low-pressure oil circuit. Under the micro-pressure of the micro-pressure chamber, the housing assembly and the back-driving piston 2 are close to the rear end side of the drill rod 1 to avoid interference with the rotation and impact action of the drill rod 1. The power head is stuck in the drilling stage: as shown in FIG. Figure 4 and Figure 5As shown, when the drill bit is stuck in the power head, an external force (generally manual force) pulls the rest of the power head structure except the drill rod 1 backward, but the drill rod cannot be pulled out. During the reverse movement of the shell assembly driving the back-hitting piston 2 to pull out the drill rod 1, the control chamber 401 is automatically and only connected to the high-pressure oil circuit through the control oil circuit. At this time, the high-pressure oil enters the control chamber 401 through the control oil circuit to form a high-pressure chamber in the control chamber 401. Under the action of the high oil pressure, the back-hitting piston 2 moves in the reverse direction to drive the drill rod 1 to move in the reverse direction until the drill rod is pulled out. During the reverse movement of the back-hitting piston 2, the control chamber 401 will be reconnected with the high-pressure oil circuit and the low-pressure oil circuit through the control oil circuit to form a micro-pressure chamber. At this time, the force of the reverse movement of the back-hitting piston 2 disappears, and the drill rod is also unstuck, and the power head performs normal impact drilling.

[0038] The hydraulic back-hitting impact power head of the present invention has a simple and compact overall structure, can effectively control its axial size, and is convenient for installation on the propulsion beam of the rock drill; at the same time, oil is supplied from the inside of the impact device, and when the drill is stuck and the external force pulls the power head except the drill rod 1 to retreat, it automatically starts to back-hit, that is, the power head of the present invention can automatically identify the stuck rod according to the movement state of the back-hitting piston 2, and automatically start to back-hit, when the stuck lag is released, the control oil circuit is re-connected with the high-pressure oil circuit and the low-pressure oil circuit at the same time so that the control chamber 401 is depressurized by the low-pressure oil circuit, and the power head re-enters the normal working state, without the need for manual automatic identification of the stuck rod and manual startup of the back-hitting device for back-hitting, which effectively reduces the possibility of manual misjudgment; on the other hand, in the back-hitting device of the present invention, the oil of the control oil circuit is the high-pressure oil circuit and the low-pressure oil circuit in the impact device arranged at the rear, and the pressure fluctuation of the hydraulic oil is absorbed by the accumulator of the impact device itself during oil supply, so there is no need to install an accumulator in the back-hitting device, thereby effectively reducing the weight and structural complexity of the back-hitting device and improving the reliability of the equipment.

[0039] Alternatively, if Figure 1-2 As shown, the drill rod 1 is connected to the power output shaft of the gear box. When the output shaft in the gear box rotates, the speed and torque are transmitted to the drill rod 1 in the back-driving device through the internal spline of the power output shaft in the gear box, and are transmitted to the connected drill rod and drill bit through the thread at the front end of the drill rod 1. The impact device is fixedly installed at the rear of the gear box. The impact device is used to impact the rear end face of the drill rod 1 at high frequency, and transmit the impact force along the drill rod 1 to the drill bit, so that it can efficiently impact and break the rock.

[0040] Alternatively, if Figure 2 and Figure 3As shown, the housing assembly includes a back-hitting housing 4 sleeved on the outer circumference of the drill rod 1, and a drill rod sleeve 3 limitedly installed in the back-hitting housing 4. The back-hitting piston 2 is located in the back-hitting housing 4, and the drill rod sleeve 3 is installed on the outer circumference of the back-hitting piston 2, and the front end of the drill rod sleeve 3, the back-hitting housing 4, and the back-hitting piston 2 are surrounded to form a control chamber 401, and the control oil circuit is arranged in the back-hitting housing 4, the drill rod sleeve 3 and the back-hitting piston 2. In this optional solution, the structural setting of the housing assembly, the setting of the internal control chamber 401 and the arrangement of the control oil circuit make the overall structure of the back-hitting device simple and compact, and can effectively control its axial size, thereby facilitating the installation of the rock drill on the propulsion beam.

[0041] Furthermore, if Figure 3 As shown, the outer circle of the drill rod 1 near the gear box is convex to form a limiting step 101, and the rear end surface of the back-hitting housing 4 near the gear box is concave to form two coaxially arranged inner and outer mounting holes. The back-hitting piston 2 is limited between the bottom of the inner mounting hole and the limiting step 101, which is convenient for the subsequent control of the stroke of the back-hitting piston 2, and the stroke limiting function of the back-hitting piston 2 is described in detail in conjunction with the subsequent action process. The outer circle of the back-hitting piston 2 is convex to form a limiting flange, which is used to limit the reverse movement of the back-hitting housing 4 with the bottom of the outer mounting hole. Similarly, the stroke control function of the back-hitting housing 4 is described in detail in conjunction with the subsequent action process. The drill rod sleeve 3 is located in the outer mounting hole, and a control chamber 401 is formed between the bottom of the outer mounting hole outside the back-hitting piston 2 and the front end surface of the drill rod sleeve 3.

[0042] Alternatively, if Figure 2-5 As shown, the control oil circuit includes a high-pressure oil inlet hole 402 and a low-pressure oil return hole 403 provided through the back-hitting housing 4, a first oil inlet hole 301 and a second oil inlet hole 302 and an oil drain hole 303 provided through the drill rod sleeve 3, and an oil guide passage 21 provided through the back-hitting piston 2. The oil inlet end of the high-pressure oil inlet hole 402 is connected to the high-pressure oil circuit, and its opposite oil outlet ends are respectively connected to the oil inlet ends of the first oil inlet hole 301 and the second oil inlet hole 302, and the oil outlet end of the first oil inlet hole 301 is connected to the control chamber 401. The oil outlet end of the low-pressure oil return hole 403 is connected to the low-pressure oil circuit, and its opposite oil inlet end is connected to the oil outlet end of the oil drain hole 303. The first end of the oil guide passage 21 is connected to the control chamber 401, and the second end of the oil guide passage 21 is used to connect the oil inlet end of the oil drain hole 303 when the power head is working normally, or to connect the oil outlet end of the second oil inlet hole 302 when the drill is stuck. In the present invention, a first oil inlet hole 301, a second oil inlet hole 302 and an oil drain hole 303 are provided in the drill rod sleeve 3 for redistributing and reducing the pressure of the oil circuit to meet the oil circuit support for the subsequent back-driving piston 2 action.

[0043] like Figure 2 and Figure 3As shown, at this time, the back-hitting device is in a normal impact drilling state: a high-pressure oil port P and a low-pressure oil port T are respectively arranged on the outer wall surface of the back-hitting shell 4, and the two oil ports are respectively connected to the high-pressure oil circuit and the low-pressure oil circuit on the impact device, and a high-pressure oil inlet hole 402 connected to the high-pressure oil port P and a low-pressure oil return hole 403 connected to the low-pressure oil port T are respectively arranged in the back-hitting shell 4, and at the same time, the first oil inlet hole 301 and the second oil inlet hole 302 arranged on the drill rod sleeve 3 are respectively connected to the high-pressure oil inlet hole 402, and the oil drain hole 303 is connected to the low-pressure oil return hole 403. During normal operation, the high-pressure oil in the high-pressure oil circuit enters the control chamber 401 through the high-pressure oil port P, the high-pressure oil inlet hole 402, and the first oil inlet hole 301 in sequence. At the same time, the return oil in the control chamber 401 flows back to the low-pressure oil circuit of the impact device through the oil guide channel 21, the oil drain hole 303, the low-pressure oil return hole 403, and the low-pressure oil port T in sequence. Since the return oil of the low-pressure oil circuit is connected to the lubricating oil tank, the control chamber 401 can form a micro-pressure chamber with a pressure slightly higher than the pressure of the low-pressure oil circuit through the structural setting of the control oil circuit. At this time, due to the existence of micro-pressure in the control chamber 401, the back-hitting piston 2 and the drill rod sleeve 3 are against the right side of the back-hitting device, which does not affect the normal impact drilling of the drill rod 1.

[0044] like Figure 4 and Figure 5 As shown in the figure, when the drill bit is stuck in the power head, the power head except the drill rod 1 retreats under the action of external force, but the drill rod cannot be pulled out. At this time, when the shell assembly drives the back-hitting piston 2 to move in the opposite direction of pulling out the drill rod 1, the rear end of the back-hitting piston 2 first contacts the limit step 101 on the drill rod 1 and is limited. At this time, the shell assembly continues to retreat, and the drill rod sleeve 3 is disconnected from the oil guide channel 21 during the backward movement. In the process of continuing to retreat (the back-hitting shell 4 is connected to the oil guide channel 21 through the bottom of its outer mounting hole), the oil leakage hole 303 of the drill rod sleeve 3 is first disconnected from the oil guide channel 21. The second oil inlet hole 302 on the drill rod sleeve 3 is connected to the oil guide channel 21 (the limit flange on the back-hitting piston 2 is contacted and limited). The high-pressure oil in the high-pressure oil circuit passes through the high-pressure oil port P, the high-pressure oil inlet hole 402, the second oil inlet hole 302, and the oil guide channel 21 in sequence and then enters the control chamber 401. Under the effect of the area difference, the back-hitting piston 2 is subjected to a backward force, and the high-pressure oil in the control chamber 401 pushes the back-hitting piston 2 in the opposite direction. The back-hitting piston 2 hits the drill rod 1, so that the drill rod 1 has the force to pull out the drill rod backward. When the back-hitting piston 2 moves backward to the oil guide channel 21 and reconnects to the oil drain hole 303, the control chamber 401 connects to the oil drain hole 303 through the oil guide channel 21, and the force of the back-hitting piston 2 moving backward disappears. At the same time, the drill rod is also unstuck, and the state of the back-hitting device returns to the state of the back-hitting device. Figure 2 As shown, the power head performs normal impact drilling.

[0045] In the power head of the present invention, oil is supplied from the inside of the impact device, the oil circuit is redistributed and reduced in pressure through the drill rod sleeve 3, and the stuck rod is automatically identified according to the movement state of the back-hitting piston 2, and the back-hitting is automatically started. When the sticking delay is released, the high-pressure oil in the control chamber 401 automatically flows out from the oil drain hole 303, and the power head enters a normal working state. There is no need to manually identify the stuck rod phenomenon and open the back-hitting oil circuit, which effectively reduces the possibility of manual misjudgment.

[0046] Preferably, if Figure 3 As shown, the drill rod sleeve 3 includes a first diameter section 31 and a second diameter section 32 which are connected in the axial direction and have different outer diameters. The inner wall surface of the outer mounting hole has a bayonet which is engaged with the connection between the first diameter section 31 and the second diameter section 32 to limit the sliding of the drill rod sleeve 3 in the axial direction. In order to ensure that the oil passages on the drill rod sleeve 3 and the back-hitting housing 4 remain unobstructed during the movement of the back-hitting piston 2, the first diameter section 31 and the second diameter section 32 of different diameters are set at the front and rear sections of the drill rod sleeve 3 to perform axial limitation, so that the drill rod sleeve 3 does not have a large displacement movement inside the back-hitting housing 4.

[0047] Preferably, if Figure 3 and Figure 5 As shown, the oil guide channel 21 is formed by two intersecting oil guide holes, and at least one of the oil guide holes is a throttle hole. Therefore, when the oil is supplied normally, the throttle hole in the oil guide channel 21 is set to form a micro-pressure chamber in the control chamber 401, so that the back-hitting piston 2 and the drill rod sleeve 3 are against the right side of the back-hitting device, which does not affect the normal impact drilling of the drill rod 1. At least part of the length section of the first oil inlet hole 301 in the length direction is a damping hole. The length of the damping hole can be adjusted through theoretical calculation to make the pressure in the control chamber 401 appropriate; in the present invention, whether it is a normal working state or when the rod is stuck, the first oil inlet hole 301 can be connected to the control chamber 401 to pass high-pressure oil to the control chamber 401. At least part of the length section of the second oil inlet hole 302 in the length direction is a damping hole, which is used to prevent the high-pressure oil pressure from the impact device from being too large, so that the reverse force of the back-hitting piston 2 is too large and damages the equipment.

[0048] Preferably, if Figure 3 and Figure 5As shown, the inner wall surface of the drill rod sleeve 3 is concave to form an annular first oil collecting ring groove 304, and the first oil collecting ring groove 304 is connected to the oil inlet end of the oil drain hole 303. The outer ring surface of the back-stroke piston 2 is concave to form an annular second oil collecting ring groove 201, and the second oil collecting ring groove 201 is connected to the second end of the oil guide channel 21. The inner wall surface of the front end of the drill rod sleeve 3 is concave to form an annular oil guide ring groove, and the oil guide ring groove is connected to the oil outlet end of the first oil inlet hole 301 and the control chamber 401. In this preferred embodiment, the first oil collecting ring groove 304, the second oil collecting ring groove 201 and the oil guide ring groove are all used to increase the connection area between holes and between holes and cavities, so as to facilitate the smooth transition and connection of hydraulic oil between the drill rod sleeve 3 and the back-stroke piston 2.

[0049] Preferably, if Figure 3 and Figure 5 As shown, the housing assembly further includes a first seal 9 installed between the back-hitting housing 4 and the back-hitting piston 2, and a second seal 10 installed between the back-hitting housing 4 and the drill rod sleeve 3. In this preferred embodiment, the first seal 9 and the second seal 10 are both sealing rings, which are used to prevent the hydraulic oil from leaking between the back-hitting housing 4 and the back-hitting piston 2 and the drill rod sleeve 3, and as required, a plurality of the first seal 9 and the second seal 10 can be provided and sequentially spaced along the axial direction.

[0050] Alternatively, if Figure 2 and Figure 4 As shown, the hydraulic back-strike impact power head also includes a front guide cover 5 installed on the outer circle of the front end of the drill rod 1 and the rear end face of which abuts against the front end of the shell assembly, and a bushing 6 limited in the front guide cover 5 and installed on the outer circle of the front end of the drill rod 1. The bushing 6 is installed in conjunction with the drill rod 1 to support the drill rod 1 and ensure that the drill rod 1 does not tilt when drilling.

[0051] Alternatively, if Figure 2 and Figure 4 As shown, the hydraulic back-hitting impact power head also includes a skeleton oil seal 7 and a retaining ring 8 which are sequentially installed in the front guide cover 5 along the axial direction. The skeleton oil seal 7 and the retaining ring 8 are also installed on the outer circle of the front end of the drill rod 1, and the skeleton oil seal 7 is axially located between the retaining ring 8 and the bushing 6. The skeleton oil seal 7 is arranged in front of the bushing 6, and the skeleton oil seal 7 is used to ensure that external dirt does not enter the inside of the back-hitting device. The bushing 6 is lubricated by adding grease from the outside, and the retaining ring 8 limits the skeleton oil seal 7 in the axial direction.

[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A hydraulic back-hitting impact power head, characterized in that: include: A gearbox for providing rotational power, and a back-hitting device and an impact device connected to the front and rear ends of the gearbox, the back-hitting device comprising a housing assembly fixed to the gearbox, a drill rod (1) axially mounted in the housing assembly, a back-hitting piston (2) limited in the housing assembly and slidably mounted on the outer circle of the drill rod (1), the front end of the drill rod (1) being connected to a drill rod, the rear end of the drill rod (1) being connected to a power output shaft of the gearbox, and the impact device being used to impact the rear end of the drill rod (1); A sealed control chamber (401) is formed between the housing assembly and the back-strike piston (2), and a control oil circuit in communication with the control chamber (401) is also provided in the housing assembly and the back-strike piston (2), and the control oil circuit is respectively connected to a high-pressure oil circuit and a low-pressure oil circuit in the impact device; The control chamber (401) is used to connect the high-pressure oil circuit and the low-pressure oil circuit respectively through the control oil circuit to form a micro-pressure chamber when the power head is working normally, so that the back-hitting piston (2) and the housing assembly are close to the rear end side of the drill rod (1), so that the back-hitting device does not work and also avoids interference with the movement of the drill rod (1); The control chamber (401) is also used for automatically connecting only with the high-pressure oil circuit to form a high-pressure chamber through the control oil circuit when the housing assembly drives the back-hitting piston (2) to move in the reverse direction to pull out the drill rod (1) under the action of external force when the drill is stuck, thereby pushing the back-hitting piston (2) to drive the drill rod (1) to move in the reverse direction to pull out the drill rod, and when the drill rod is pulled out, the control chamber (401) is connected with the high-pressure oil circuit and the low-pressure oil circuit again through the control oil circuit to form a micro-pressure chamber.

2. The hydraulic back-hitting impact power head according to claim 1, characterized in that: The housing assembly comprises a reverse striking housing (4) sleeved on the outer circumference of a drill rod (1), and a drill rod sleeve (3) limitedly installed in the reverse striking housing (4); The back-hitting piston (2) is located in the back-hitting housing (4), and the drill rod sleeve (3) is installed on the outer circle of the back-hitting piston (2). The front end of the drill rod sleeve (3), the back-hitting housing (4) and the back-hitting piston (2) are surrounded to form a control chamber (401), and the control oil circuit is arranged in the back-hitting housing (4), the drill rod sleeve (3) and the back-hitting piston (2).

3. The hydraulic back-hitting impact power head according to claim 2, characterized in that: The outer circle of the drill rod (1) near the gear box is convex to form a limiting step (101), and the rear end surface of the counter-punch housing (4) near the gear box is concave to form two coaxially arranged inner and outer mounting holes; The back-stroke piston (2) is limited between the bottom of the inner mounting hole and the limiting step (101); The outer circle of the back-strike piston (2) is convex to form a limiting flange, which is used to abut against the bottom of the external mounting hole to limit the reverse movement of the back-strike housing (4); The drill rod sleeve (3) is located in the external mounting hole, and a control chamber (401) is formed between the bottom of the external mounting hole outside the back-hitting piston (2) and the front end surface of the drill rod sleeve (3).

4. The hydraulic back-hitting impact power head according to claim 3, characterized in that: The drill rod sleeve (3) comprises a first diameter section (31) and a second diameter section (32) which are connected in the axial direction and have different outer diameters; The inner wall surface of the outer mounting hole has a snap-fit ​​socket which is snap-fitted with the connection between the first diameter section (31) and the second diameter section (32) so as to limit the sliding movement of the drill rod sleeve (3) along the axial direction.

5. The hydraulic back-hitting impact power head according to claim 2, characterized in that: The control oil circuit comprises a high-pressure oil inlet hole (402) and a low-pressure oil return hole (403) which are arranged through the back-hitting housing (4), a first oil inlet hole (301) and a second oil inlet hole (302) and an oil drain hole (303) which are arranged through the drill rod sleeve (3), and an oil guide passage (21) which is arranged through the back-hitting piston (2); The oil inlet end of the high-pressure oil inlet hole (402) is connected to the high-pressure oil circuit, and the oil outlet end thereof is respectively connected to the oil inlet ends of the first oil inlet hole (301) and the second oil inlet hole (302), and the oil outlet end of the first oil inlet hole (301) is connected to the control chamber (401); The oil outlet end of the low-pressure oil return hole (403) is connected to the low-pressure oil circuit, and the oil inlet end opposite thereto is connected to the oil outlet end of the oil drain hole (303); The first end of the oil guide channel (21) is connected to the control chamber (401), and the second end of the oil guide channel (21) is used to connect to the oil inlet end of the oil drain hole (303) when the power head is working normally, or to connect to the oil outlet end of the second oil inlet hole (302) when the drill is stuck.

6. The hydraulic back-strike impact power head according to claim 5, characterized in that: The oil guide channel (21) is formed by two intersecting oil guide holes connected to each other, and at least one of the oil guide holes is a throttling hole; At least a portion of the length of the first oil inlet hole (301) in the length direction is a damping hole; At least a portion of the length of the second oil inlet hole (302) in the length direction is a damping hole.

7. The hydraulic back-strike impact power head according to claim 5, characterized in that: The inner wall surface of the drill rod sleeve (3) is concave to form an annular first oil collecting ring groove (304), and the first oil collecting ring groove (304) is communicated with the oil inlet end of the oil drain hole (303); The outer ring surface of the back-stroke piston (2) is concave to form an annular second oil collecting ring groove (201), and the second oil collecting ring groove (201) is communicated with the second end of the oil guide channel (21); The inner wall surface of the front end of the drill rod sleeve (3) is concavely processed to form an annular oil guide ring groove, and the oil guide ring groove is connected with the oil outlet end of the first oil inlet hole (301) and the control chamber (401).

8. The hydraulic back-hitting impact power head according to claim 2, characterized in that: The housing assembly also includes a first sealing member (9) installed between the back-stroke housing (4) and the back-stroke piston (2), and A second sealing member (10) is installed between the counter-attacking housing (4) and the drill rod sleeve (3).

9. The hydraulic back-strike impact power head according to claim 1, characterized in that: The hydraulic back-strike impact power head also includes a front guide cover (5) mounted on the front end outer circle of the drill rod (1) and with its rear end face abutting against the front end of the housing assembly, and a bushing (6) limited in the front guide cover (5) and mounted on the front end outer circle of the drill rod (1), so as to ensure that the drill rod (1) does not tilt when drilling a hole through the bushing (6).

10. The hydraulic back-hitting impact power head according to claim 9, characterized in that: The hydraulic back-strike impact power head also includes a skeleton oil seal (7) and a retaining ring (8) which are sequentially installed in the front guide cover (5) in a limited manner along the axial direction; The skeleton oil seal (7) and the retaining ring (8) are also mounted on the outer circle of the front end of the drill rod (1), and the skeleton oil seal (7) is axially located between the retaining ring (8) and the bushing (6).

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