Hydraulic rock drill

Abstract

The utility model discloses a hydraulic rock drill which comprises a machine body composed of a machine base, a cylinder body, a middle body, a gear box, a gear box cover and a machine head which are sequentially connected, a first cavity for containing an impact piston and a second cavity for containing a bit shank are formed in the machine body, and a cooling lubricating cavity communicated with the first cavity and the second cavity is formed in the machine body. An air inlet chamber is formed in the machine base, and an air inlet communicated with the air inlet chamber is formed in the rear end of the machine base. The impact piston is provided with a central channel which is communicated with the air inlet chamber and the cooling and lubricating air chamber; an air passing channel which is communicated with a gap between the bit shank, the rotary assembly and the machine head and a gap between the bit shank and the machine head part is formed in the machine head; cooling and lubricating air introduced into the air inlet chamber enters the cooling and lubricating cavity through the center channel of the impact piston, sequentially passes through the bit shank, the gap between the rotary assembly and the machine head and the air passing channel, enters the gap between the head of the bit shank and the machine head and is blown out, and the situation that the cooling effect is poor due to the fact that air flow is poor after heat exchange is avoided.

Description

Technical Field

[0001] The utility model relates to a hydraulic rock drill, belonging to the technical field of rock drills. Background Art

[0002] Rock drills operate on the principle of impact crushing. During operation, the piston reciprocates at high frequency, continuously striking the drill adapter. Under the impact force, the head of the drill adapter crushes the rock and drills into the drill adapter to a certain depth, forming an indentation. After the piston retracts, the drill adapter rotates a certain angle, and the piston moves forward again, striking the drill adapter again, creating a new indentation. The fan-shaped rock between the two indentations is sheared off by the horizontal force generated by the drill adapter. The piston continuously strikes the drill adapter, and compressed air or water is continuously fed through the center hole of the drill adapter to expel the rock debris, thus forming a circular drill hole of a certain depth.

[0003] During the operation of a hydraulic rock drill, the components inside will heat up. If they are not cooled down in time, the normal service life of the components will be shortened. A cooling and lubrication cavity will be left in the body of the hydraulic rock drill, and an air inlet connected to the cooling and lubrication cavity will be opened on the side of the body. Cooling and lubricating gas is sent into the cooling and lubrication cavity through the air inlet, and the cooling and lubricating gas is used to cool and lubricate the components. However, the cooling and lubrication cavity is generally preset in the middle section of the body, but the position of the air supply system on the trolley is fixed. In order to adapt, it is usually necessary to open multiple air inlets on the body, which relatively increases the processing difficulty; at the same time, the cooling and lubricating gas flows from the middle section to both ends. However, under normal circumstances, no exhaust port is opened or an exhaust gap is set at the rear end of the tail, and the gas flow after heat exchange in the rear end of the head is poor, resulting in poor cooling effect on the components inside the rear end of the body. Utility Model Content

[0004] The purpose of the utility model is to provide a hydraulic rock drill, in which the air inlet is opened at the rear end of the machine tail to improve the installation adaptability; at the same time, the cooling and lubricating air is blown from the rear end of the machine head to the head, and the poor gas flow after heat exchange and the resulting poor cooling effect will not occur.

[0005] In order to achieve the above technical effects, the technical solution adopted by the present invention is:

[0006] A hydraulic rock drill includes a body composed of a machine base, a cylinder body, an intermediate body, a gear box, a gear box cover, and a machine head connected in sequence. An impact assembly is provided in the machine base and the cylinder body; a rotary assembly is provided in the gear box and the gear box cover; and a flushing assembly is formed in the machine head.

[0007] The impact assembly forms a first chamber for accommodating the impact piston; the rotary assembly and the flushing assembly jointly form a second chamber for accommodating the shank tail, and a cooling and lubrication chamber connecting the first chamber and the second chamber is formed in the intermediate body;

[0008] Hydraulic oil is introduced into the first chamber, and the impact piston can reciprocate along the central axis of the first chamber under the push of the hydraulic oil, and the head of the impact piston can pass through the first chamber into the cooling and lubricating chamber and hit the tail of the shank, causing the shank to move axially;

[0009] The tail of the shank adapter is inserted into the rotary assembly and the rotary assembly drives the shank adapter to rotate forward or reverse along the central axis;

[0010] A central hole extending toward the head of the shank is formed on the shank body, and the flushing assembly injects a flushing medium into the central hole;

[0011] An air intake chamber is formed in the machine base, and an air intake port connected to the air intake chamber is opened at the rear end of the machine base; a central channel is formed on the impact piston to connect the air intake chamber and the cooling and lubricating air chamber; an air passage is formed in the die head to connect the shank, the gap between the rotary assembly and the die head, and the gap between the shank and the die head;

[0012] The cooling and lubricating gas introduced into the air inlet chamber enters the cooling and lubricating cavity through the central channel of the impact piston, and passes through the shank, the gap between the rotary assembly and the machine head, the air outlet channel, and enters the gap between the head of the shank and the machine head and is blown out.

[0013] Preferably, the tail of the cylinder body is embedded in the front inner cavity of the machine base, the tail of the intermediate body is embedded in the front inner cavity of the cylinder body, the tail of the gear box is embedded in the front inner cavity of the intermediate body, and the tail of the machine head is embedded in the front inner cavity of the gear box cover;

[0014] The impact assembly includes a valve sleeve, a valve body, a cylinder sleeve and an impact piston;

[0015] The valve sleeve is embedded in the engine base and closes the air inlet chamber, with its head embedded in the rear end inner cavity of the cylinder body; the valve body is installed in the front end inner cavity of the valve sleeve; the cylinder sleeve is arranged in the cylinder body, with its tail abutting against the head of the valve sleeve, and its head abutting against the tail of the intermediate body; the inner cavity of the valve sleeve is connected to the inner cavity of the cylinder sleeve; the impact piston is installed in the inner cavity of the cylinder sleeve, and during the reciprocating motion, the tail end of the impact piston can pass through the valve sleeve and enter the air inlet chamber;

[0016] The hydraulic oil pushes the valve body and the impact piston to reciprocate. When the valve body is displaced axially forward by a preset distance, the hydraulic oil pushes the impact piston forward; when the impact piston is displaced forward by a preset distance, the hydraulic oil pushes the valve body to be displaced axially backward; when the valve body is displaced axially backward by a preset distance, the hydraulic oil pushes the impact piston backward; when the impact piston is retracted by a preset distance, the hydraulic oil pushes the valve body to be displaced axially to the left, and this cycle repeats.

[0017] Preferably, an annular rear high-pressure oil chamber and a rear total oil return chamber are sequentially formed in the radial direction between the machine base and the valve sleeve, and between the machine base, the valve sleeve, and the tail of the cylinder body;

[0018] A rear end oil return cavity is formed between the inner cavity of the valve sleeve and the inner cavity of the cylinder sleeve and the valve body;

[0019] The cylinder liner is radially formed with an annular middle oil return chamber, a front oil return chamber and a front high-pressure oil chamber in sequence from the rear to the front, and is isolated by an impact piston. The middle oil return chamber, the rear oil return chamber and the rear main oil return chamber are connected;

[0020] The valve sleeve is provided with a plurality of high-pressure oil channels for connecting the rear high-pressure oil chamber with the inner cavity of the valve sleeve;

[0021] The valve body closes the high-pressure oil channel. After the hydraulic oil is injected into the rear high-pressure oil chamber, it pushes the valve body to move axially forward to open the high-pressure oil channel. The rear high-pressure oil chamber is connected to the inner cavity of the valve sleeve. The hydraulic oil enters the inner cavity of the valve sleeve and pushes the impact piston to move axially forward.

[0022] When the impact piston moves forward a preset distance, the front high-pressure oil chamber is connected to the front oil return chamber, and the hydraulic oil pushes the valve body to move axially backward to close the high-pressure oil channel. The impact piston completes the impact under the action of the hydraulic oil and retreats backward;

[0023] When the impact piston retreats a preset distance, the front oil return chamber is connected with the middle oil return chamber, the rear oil return chamber, and the rear total oil return chamber; the high-pressure oil injected into the rear high-pressure oil chamber pushes the valve body to move axially forward to open the high-pressure oil channel so that the rear high-pressure oil chamber is connected with the inner cavity of the valve sleeve, and the hydraulic oil enters the inner cavity of the valve sleeve and pushes the impact piston to move axially forward, and the cycle repeats.

[0024] Preferably, a plurality of back-thrust channels connected to the high-pressure oil channel and the rear end oil return chamber are distributed axially and circumferentially in the head portion of the valve sleeve;

[0025] A plurality of forward thrust passages are distributed axially and circumferentially in the rear end of the cylinder liner, communicating with the rear end oil return chamber and the front end oil return chamber;

[0026] A rear push rod and a front push rod are respectively slidably arranged in the rear push channel and the front push channel for pushing the valve body axial displacement under the action of hydraulic oil, wherein the diameter of the front push rod is larger than that of the rear push rod;

[0027] An accumulator is installed on the side of the engine base, and the liquid side of the accumulator is connected to the rear high-pressure oil chamber; and an oil inlet channel for connecting the rear high-pressure oil chamber and the front high-pressure oil chamber is formed on the valve body and the cylinder sleeve;

[0028] An oil inlet communicated with the rear high-pressure oil chamber and an oil outlet communicated with the rear total return oil chamber are provided on the side of the machine base.

[0029] Preferably, a plurality of step seals are embedded in the rear end inner cavity of the valve sleeve for preventing the hydraulic oil from leaking to the rear end, and a sealing assembly is provided in the inner cavity at the abutting end of the cylinder body and the intermediate body for preventing the hydraulic oil from leaking to the front end;

[0030] An annular rear end leakage oil chamber is formed in the rear end inner cavity of the valve sleeve located at the front end of the step seal; a front end leakage oil chamber is formed between the sealing assembly and the inner cavity of the cylinder body;

[0031] The front leakage oil chamber is connected to the rear total oil return chamber; the rear leakage oil chamber is connected to the middle oil return chamber, and is connected to the rear total oil return chamber through the middle oil return chamber and the rear oil return chamber.

[0032] Preferably, the rotary assembly comprises a cycloid motor, a pinion gear and a gear;

[0033] The pinion is arranged in the upper cavity of the gear box, and needle bearings are arranged on the outer sides of both ends of the pinion. The pinion rotates relative to the upper cavity of the gear box through the needle bearings.

[0034] The large gear is clamped in the gear box and meshes with the small gear. Conical bearings are provided on the outside of both ends of the large gear. The large gear rotates relative to the gear box through the conical bearings.

[0035] The shank is inserted through the large gear and has a clearance fit with the large gear without any rotation;

[0036] The cycloid motor is installed outside the upper cavity of the gearbox and is used to drive the small gear to rotate forward or reverse, thereby driving the large gear and the drill tail to rotate synchronously.

[0037] Preferably, the rotary assembly further comprises a follower sleeve, a rear stop sleeve and a front stop sleeve;

[0038] The follower sleeve is set in the front end inner cavity of the large gear. The shank is inserted through the follower sleeve. Along the length direction of the shank, teeth are formed around the shank. A tooth groove is formed in the inner cavity of the follower sleeve. The shank is engaged with the tooth groove of the follower sleeve to achieve non-rotational and clearance fit.

[0039] A corresponding arc groove is formed around the outer surface of the follower sleeve and the front end inner cavity of the large gear and extends along the length direction of the follower sleeve, and a follower column is embedded in the corresponding arc groove, so that the large gear drives the follower sleeve to follow the movement through the follower column;

[0040] The rear stop sleeve is set in the inner cavity of the large gear at the rear end of the follower sleeve, and is used to limit the rear axial displacement distance of the shank; the front stop sleeve is embedded in the rear end inner cavity of the machine head and abuts against the follower sleeve, follower column, large gear and gear box cover, and the maximum straight-line distance from the outer edge of the tooth to the horizontal center line of the shank is greater than the front end opening radius of the front stop sleeve, which is used to prevent the follower sleeve and follower column from moving forward and limit the forward axial displacement distance of the shank.

[0041] Preferably, the head of the large gear extends into the gear box cover, and a lubricating oil chamber is formed between the large gear and the small gear;

[0042] A shaft seal is provided in the rear end inner cavity of the gearbox and the rear end inner cavity of the gearbox cover, which is in contact with the outer peripheral body of the corresponding end of the large gear and is used to prevent the lubricating oil in the lubricating oil cavity from leaking. A retaining ring is also embedded in the rear end inner cavity of the gearbox and the rear end inner cavity of the gearbox cover at the rear end of the shaft seal to prevent the displacement of the shaft seal.

[0043] A sealing sleeve is provided outside the tapered bearing located outside the large gear head, which is in contact with and sealed against the inner wall of the gear box and the gear box cover to prevent leakage of lubricating oil in the lubricating oil cavity.

[0044] Preferably, the flushing assembly includes a water trough formed in the cavity of the handpiece, a water hole connecting the water trough and the central hole of the handpiece is provided on the shank, and a flushing water outlet connected to the water trough is provided on the handpiece;

[0045] The flushing water injected through the flushing water inlet flows into the center hole of the shank through the water trough and water hole and flows out;

[0046] Two U-shaped seals are provided in the inner cavity of the machine head located at the front and rear ends of the water trough, which are sealed with the shank tail to prevent leakage of flushing water; and a leakage water cavity is formed in the inner cavity of the machine head at the rear end of the water trough, and a U-shaped seal is also provided in the leakage water cavity to prevent leakage of leaked water to the rear end; a plurality of drainage holes are provided on the machine head, which are connected with the leakage water cavity and are used to discharge the leaked water.

[0047] Preferably, a copper sleeve is embedded in the head cavity of the handpiece, and a retaining ring for preventing the copper sleeve from falling off is embedded in the head cavity of the handpiece, and the shank is inserted through the copper sleeve;

[0048] An air groove connected to the air passage is formed in the cavity of the handpiece located outside the rear end of the copper sleeve, and a plurality of air holes connecting the air groove and the gap between the copper sleeve and the shank are opened on the copper sleeve;

[0049] Several air guide holes are provided on the front baffle sleeve for connecting the air passage with the large gear, gear box cover and the gap between the machine head; the cooling and lubricating air enters the air guide holes and the air passage through the gap between the front baffle sleeve and the machine head, and the cooling and lubricating air entering the air guide holes enters the gap between the large gear, gear box cover and the machine head and is blown out.

[0050] The beneficial effects of the present invention are:

[0051] 1. The air inlet is opened at the rear end of the drill rig, so it can be applied regardless of which side of the drill rig the rig air supply system and air pipe are arranged on, improving installation adaptability. At the same time, the cooling and lubricating gas introduced into the air inlet chamber enters the cooling and lubricating cavity through the central channel of the impact piston, and then passes through the drill adapter, the gap between the rotary assembly and the drill head, and the air outlet channel in sequence. It enters the gap between the head of the drill adapter and the drill head and is blown out. It can then act on the entire internal components of the drill body, and the poor cooling effect caused by poor gas flow after heat exchange will not occur, thereby improving the cooling and lubrication effect.

[0052] 2. The installation angles of the tail, gearbox and head can be adjusted according to the placement of the flushing system to facilitate assembly on the drilling rig;

[0053] 3. The front and rear baffles can also play a guiding and supporting role, preventing the shank from radially deflecting, improving the stability of the shank during impact and rotation, and ensuring the service life of the shank.

[0054] 4. The design of no radial relative motion is adopted. The inner cavity of the follower sleeve and the drill tail are formed with meshing teeth and groove structures. The large gear and the follower sleeve are connected into an integrated structure through the follower column. When used together, the large gear drives the follower sleeve to rotate, and the follower sleeve drill tail rotates, which can improve the service life of the parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 It is a perspective view of a hydraulic rock drill;

[0056] Figure 2 This is a schematic diagram of the component structure of a hydraulic rock drill;

[0057] Figure 3 A schematic diagram of the bores, channels, and cavities in a hydraulic rock drill;

[0058] Figure 4 This is a schematic diagram of the channel at the nose;

[0059] Figure 5 Schematic diagram of the structure of the valve sleeve;

[0060] Figure 6 is another structural schematic diagram of the valve sleeve;

[0061] Figure 7 It is a structural diagram of the cylinder liner;

[0062] Figure 8 is another structural schematic diagram of the cylinder liner;

[0063] Figure 9 It is a structural diagram of the impact piston;

[0064] Figure 10This is a schematic diagram of the structure of the connection between the shank tail and the large gear;

[0065] Figure 11 It is a structural diagram of the follower sleeve;

[0066] Figure 12 This is a schematic diagram of the structure at the nose;

[0067] Figure 13 This is a schematic diagram of the structure of the copper sleeve.

[0068] The main reference numerals in the figures have the following meanings:

[0069] 1. Machine base, 2. Cylinder body, 3. Intermediate body, 4. Gear box, 5. Gear box cover, 6. Machine head, 7. Positioning pin, 8. Long screw, 9. Short screw, 10. Bolt, 11. Impact piston, 12. Boring tail, 13. Cooling and lubrication chamber, 14. Center hole, 15. Inlet chamber, 16. Inlet port, 17. Center channel, 18. Air passage, 19. Valve sleeve, 20. Valve body, 21. Cylinder sleeve, 22. Piston guide sleeve, 23. Sealing guide sleeve, 24. Step seal, 25, oil seal, 26, rear high-pressure oil chamber, 27, rear total return oil chamber, 28, high-pressure oil channel, 29, rear thrust channel, 30, rear oil return chamber, 31, middle oil return chamber, 32, front oil return chamber, 33, front high-pressure oil chamber, 34, channel 1, 35, channel 2, 36, channel 3, 37, sinking chamber, 38, oil passage, 39, leakage ring chamber, 40, oil return channel, 41, forward thrust channel, 42, rear leakage oil chamber, 43 , inclined hole, 44, front end leakage oil chamber, 45, through hole, 46, rear push rod, 47, front push rod, 48, rear stage, 49, front stage, 50, force surface A, 51, force surface C, 52, cross section B, 53, force surface B, 54, inner stage D, 55, inner stage E, 56, accumulator, 57, cycloid motor, 58, small gear, 59, large gear, 60, needle roller bearing, 61, tapered bearing, 62, follower sleeve, 63, Rear baffle, 64, front baffle, 65, teeth, 66, tooth groove, 67, arc groove, 68, follower column, 69, lubricating oil chamber, 70, shaft seal, 71, retaining ring, 72, sealing sleeve, 73, water trough, 74, water hole, 75, flushing water outlet, 76, U-shaped seal, 77, leakage water chamber, 78, drain hole, 79, copper sleeve, 80, retaining ring, 81, air groove, 82, air hole, 83, air guide hole, 84, oil inlet, 85, oil outlet. DETAILED DESCRIPTION

[0070] The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0071] This embodiment provides a hydraulic rock drill, see Figure 1-13As shown, the machine body comprises a base 1, cylinder body 2, intermediate body 3, gearbox 4, gearbox cover 5, and head 6, which are connected in sequence. The tail of the cylinder body 2 is embedded in the front inner cavity of the base 1, the tail of the intermediate body 3 is embedded in the front inner cavity of the cylinder body 2, the tail of the gearbox 4 is embedded in the front inner cavity of the intermediate body 3, and the tail of the head 6 is embedded in the front inner cavity of the gearbox cover 5. Except for the abutment surface between the head 6 and the gearbox cover 5, the remaining abutment surfaces between two adjacent components are sealed with sealing rings. The base 1, cylinder body 2, and intermediate body 3 are positioned at their abutment ends by multiple locating pins 7 and assembled into one piece by four long screws 8. The intermediate body 3 is positioned at its abutment end with the gearbox 4 by multiple locating pins 7 and assembled into one piece with the gearbox cover 5 by four short screws 9. The head 6 is mounted to the gearbox cover 5 by multiple bolts 10.

[0072] An impact assembly is housed within the machine base 1 and cylinder block 2; a rotary assembly is housed within the gearbox 4 and gearbox cover 5; and a flushing assembly is formed within the machine head 6. The impact assembly forms a first chamber for accommodating an impact piston 11; the rotary and flushing assemblies together form a second chamber for accommodating a shank adapter 12. A cooling and lubrication chamber 13 is formed within the intermediate body 3, connecting the first and second chambers. Hydraulic oil is introduced into the first chamber, pushing the impact piston 11 back and forth along the central axis of the first chamber. The head of the impact piston 11 can then pass through the first chamber, enter the cooling and lubrication chamber 13, and strike the rear end of the shank adapter 12, causing axial displacement of the shank adapter 12.

[0073] The tail end of the shank adapter 12 is inserted into the rotary assembly, which drives the shank adapter 12 to rotate forward or reverse along its central axis. A central hole 14 extending toward the head of the shank adapter 12 is formed in the shaft of the shank adapter 12. The flushing assembly injects flushing medium into the central hole 14. An air inlet chamber 15 is formed in the rear end of the machine base 1, and an air inlet 16 is provided at the rear end of the machine base 1, communicating with the air inlet chamber 15. A central passage 17 is formed in the impact piston 11, connecting the air inlet chamber 15 with the cooling and lubricating air chamber. An air passage 18 is formed in the handpiece 6, connecting the shank adapter 12, the gap between the rotary assembly and the handpiece 6, and the gap between the shank adapter 12 and the upper portion of the handpiece 6. Cooling and lubricating air entering the air inlet chamber 15 enters the cooling and lubricating chamber 13 through the central passage 17 of the impact piston 11. The air then passes through the shank adapter 12, the gap between the rotary assembly and the handpiece 6, and the air passage 18, before entering the gap between the head of the shank adapter 12 and the upper portion of the handpiece 6 and being blown out.

[0074] Specifically, the impact assembly includes a valve sleeve 19, a valve body 20, a cylinder sleeve 21 and an impact piston 11; the valve sleeve 19 is embedded in the front end inner cavity of the machine base 1 and closes the air intake chamber 15, and the head is embedded in the rear end inner cavity of the cylinder body 2; the valve body 20 is installed in the front end inner cavity of the valve sleeve 19; the cylinder sleeve 21 is arranged in the cylinder body 2 and the tail end abuts against the head end of the valve sleeve 19 and is also positioned by the locating pin 7, and the head end abuts against the tail end of the intermediate body 3; the inner cavity of the valve sleeve 19 is connected to the inner cavity of the cylinder sleeve 21.

[0075] In order to prevent the hydraulic oil used to drive the impact piston 11 to reciprocate from leaking into the cooling and lubrication chamber 13, a restricted area is formed between the front end inner cavity of the cylinder liner 21 and the rear end inner cavity of the intermediate body 3, and a piston guide sleeve 22 is provided in the front end inner cavity of the cylinder liner 21, and a sealing guide sleeve 23 is provided in the rear end inner cavity of the intermediate body 3. The piston guide sleeve 22 abuts against the sealing guide sleeve 23. The impact piston 11 is installed in the inner cavity of the cylinder liner 21, and passes through the valve sleeve 19, the piston guide sleeve 22, and the sealing guide sleeve 23 and extends to the cooling and lubrication chamber 13 at the rear end of the intermediate body 3. During the reciprocating motion, the tail end of the impact piston 11 can pass through the valve sleeve 19 and enter the rear end chamber of the tail of the machine. Step seals 24 for preventing leakage of hydraulic oil are installed in the two grooves at the rear end of the valve sleeve 19 and the two grooves of the sealing guide sleeve 23. At the same time, an oil seal 25 for the impact piston 11 to pass through is also provided at the front end of the sealing guide sleeve 23. The oil seal 25 further prevents the hydraulic oil from leaking into the cooling and lubricating chamber 13, and can prevent the cooling and lubricating gas in the cooling and lubricating chamber 13 from entering the rear end body.

[0076] An annular rear high-pressure oil chamber 26 and a rear total oil return chamber 27 are radially formed between the engine base 1 and the valve sleeve 19, and between the engine base 1, the valve sleeve 19, and the rear end of the cylinder body 2. An oil inlet communicating with the rear high-pressure oil chamber 26 and an oil outlet communicating with the rear total oil return chamber 27 are formed on one side of the engine base 1. Multiple high-pressure oil passages 28 are formed in the valve sleeve 19 to connect the rear high-pressure oil chamber 26 with the inner cavity of the valve sleeve 19. Four rearward thrust passages 29 are formed in the head of the valve sleeve 19, and the four rearward thrust passages 29 are correspondingly connected to four of the high-pressure oil passages 28.

[0077] A rear oil return chamber 30 is formed between the inner cavities of the valve sleeve 19 and the inner cavities of the cylinder sleeve 21, and the valve body 20. An annular intermediate oil return chamber 31, a front oil return chamber 32, and a front high-pressure oil chamber 33 are radially formed in order from rear to front within the cylinder sleeve 21, separated by the impact piston 11. The intermediate oil return chamber 31 communicates with the rear oil return chamber 30 via a first port 34 within the cylinder sleeve 21, and communicates with the rear main oil return chamber 27 via a second port 35 within the valve sleeve 19, which communicates with port 1 34, and a third port 36, which connects to port 2 35.

[0078] Two sinks 37 are formed in the cylinder liner 21, communicating with the front high-pressure oil chamber 33. Multiple interconnected oil passages 38 are formed within the valve sleeve 19 and cylinder liner 21. One end of each of the multiple oil passages 38 communicates with multiple high-pressure oil passages 28, and the other end communicates with the corresponding sink 37, thereby connecting the front high-pressure oil chamber 33 with the rear high-pressure oil chamber 26. A leakage annular chamber 39 is also formed between the cylinder liner 21 and the cylinder body 2, located in front of the rear high-pressure oil chamber 26. An oil return passage 40 is provided within the cylinder liner 21, connecting the leakage annular chamber 39 with the intermediate oil return chamber 31. The oil return passage 40 corresponds to the channel 1 34. The rear end of the cylinder body 2 is provided with multiple forward thrust passages 41, each corresponding to the rearward thrust passages 29, and the front end of which communicates with the front oil return chamber 32.

[0079] An annular rear end leakage oil chamber 42 is formed between the valve sleeve 19 located on the front side of the step seal 24 and the impact piston 11. The rear end leakage oil chamber 42 is connected to the rear end total return oil chamber 27 through an inclined hole 43 on the valve sleeve 19; a front end leakage oil chamber 44 is formed between the piston guide sleeve 22, the sealing guide sleeve 23 and the inner cavity of the cylinder body 2. The front end leakage oil chamber 44 is connected to the leakage ring chamber 39 through a through hole 45 opened on the cylinder sleeve 21.

[0080] A rear push rod 46 and a front push rod 47 are respectively embedded in each rear push channel 29 and each front push channel 41. The diameter of the front push rod 47 is larger than that of the rear push rod 46, and the rear push rod 46 and the front push rod 47 can move freely in the corresponding rear push channel 29 and the front push channel 41 (clearance fit); the valve body 20 is installed in the front end inner cavity of the valve sleeve 19 and can move freely in the front end inner cavity of the valve sleeve 19 (clearance fit). In the initial state, the rear end of the valve body 20 is aligned with the front end of the valve sleeve 19. The inner cavity of the end abuts against each other to close the inner end of the high-pressure oil channel 28, and the front end of the valve body 20 and the rear end of the cylinder liner 21 have a gap connecting the inner cavity of the valve body 20 and the rear end oil return cavity 30; an annular protrusion is formed on the outer periphery of the front end of the valve body 20, the rear push rod 46 abuts against the rear end surface of the protrusion, and the front push rod 47 abuts against the front end surface of the protrusion. Under the action of hydraulic oil, the valve body 20 can be axially displaced relative to the impact piston 11 in the space formed by the front end inner cavity of the valve sleeve 19 and the rear end inner cavity of the cylinder liner 21.

[0081] The impact piston 11 has a rear stage 48 and a front stage 49. The rear end of the rear stage 48 of the impact piston 11 forms a force surface A50, and the front end forms a force surface C51. The rear end of the front stage 49 of the impact piston 11 forms a cross-section B52, and the front end forms a force surface B53. The force area of ​​the force surface A50 is greater than the force areas of the force surfaces C51 and B53; and the rear stage 48 of the impact piston 11 can be axially displaced in the front end inner cavity of the valve body 20 and the rear end inner cavity of the cylinder liner 21. The cylinder liner 21 has an inner stage D54 for separating the front end return oil chamber 32 and the front end high-pressure oil chamber 33, and an inner stage E55 for separating the front end high-pressure oil chamber 33 and the front end inner cavity of the cylinder liner 21. The front stage 49 of the impact piston 11 can be axially displaced in the inner stage D54, the front end high-pressure oil chamber 33 and the inner stage E55 of the cylinder liner 21.

[0082] An accumulator 56 (with a nitrogen charging connection) is installed on one side of the base 1. The base 1 is provided with multiple internal holes connecting the liquid side of the accumulator 56 and the rear high-pressure oil chamber 26. The accumulator 56, a common structure in existing rock drills, serves as a liquid compensation device, eliminating pulsation and reducing noise, absorbing hydraulic shock, and acting as a hydraulic air spring.

[0083] The shank 12 is horizontally and rotatably arranged in the gear box 4, the gear box cover 5 and the machine head 6 and extends to the outside of the front end of the machine head 6. The rear end of the shank 12 extends into the cooling and lubrication cavity 13 of the intermediate body 3 and leaves a certain distance from the front end of the impact piston 11 to be struck. When the impact piston 11 is axially displaced forward by the action of hydraulic oil, it acts on the shank 12 to cause axial displacement.

[0084] The rotary assembly includes a cycloidal motor 57, a pinion 58, and a large gear 59. The pinion 58 is located in the upper cavity of the gearbox 4 and is rotatably connected to the upper cavity of the gearbox 4 via needle roller bearings 60 located on the outer ends. The large gear 59 is mounted in the lower cavity of the gearbox 4 and meshes with the pinion 58. It is also rotatably arranged relative to the gearbox 4 via tapered bearings 61 located on the outer ends. The shank adapter 12 passes through the large gear 59 and has a non-rotating, clearance fit with the large gear 59. The cycloidal motor 57 is mounted outside the upper cavity of the gearbox 4 and is used to drive the pinion 58 in forward or reverse rotation, thereby driving the large gear 59 and the shank adapter 12 to rotate synchronously.

[0085] The rotary assembly also includes a follower sleeve 62, a rear stop sleeve 63 and a front stop sleeve 64; the follower sleeve 62 is arranged in the front end inner cavity of the large gear 59, the drill tail 12 is inserted through the follower sleeve 62, and meshing teeth and groove structures are formed on the inner cavity of the follower sleeve 62 and the drill tail 12; in the present embodiment, a tooth tooth 65 structure is formed on the drill tail 12, and a tooth groove 66 structure is formed in the inner cavity of the follower sleeve 62, and the two are non-rotating and clearance-matched through the meshing of the teeth 65 and the tooth grooves 66, that is, relative rotation cannot occur between the large gear 59 and the drill tail 12; at the same time, a corresponding arc groove 67 is formed around the outer surface of the follower sleeve 62 and the front end inner cavity of the large gear 59 and extending along the length direction of the follower sleeve 62, and a follower column 68 is embedded in the corresponding arc groove 67, and the large gear 59 drives the follower sleeve 62 to follow the movement through the follower column 68.

[0086] The rear stop sleeve 63 is arranged in the inner cavity of the large gear 59 located at the rear end of the follower sleeve 62, and is used to limit the backward axial displacement distance of the shank 12; the front stop sleeve 64 is embedded in the rear end inner cavity of the machine head 6 and abuts against the follower sleeve 62, the follower column 68, the large gear 59 and the gear box cover 5, and the maximum straight-line distance from the outer edge of the tooth 65 to the horizontal center line of the shank 12 is greater than the front end opening radius of the front stop sleeve 64, which is used to prevent the follower sleeve 62 and the follower column 68 from moving forward, and limit the forward axial displacement distance of the shank 12, and can prevent the shank 12 from detaching from the machine body after being hit.

[0087] The head of the large gear 59 extends into the gearbox cover 5, and a lubricating oil chamber 69 is formed between the large gear 59 and the small gear 58. A shaft seal 70 is installed in the rear end inner cavity of the gearbox 4 and the rear end inner cavity of the gearbox cover 5, abutting the outer circumference of the corresponding end of the large gear 59 to prevent the lubricating oil from the lubricating oil chamber 69. A retaining ring 71 is embedded in the rear end inner cavity of the gearbox 4 and the rear end inner cavity of the gearbox cover 5, located behind the shaft seal 70, to prevent the shaft seal 70 from moving. A sealing sleeve 72 is also installed outside the tapered bearing 61 located outside the head of the large gear 59, abutting and sealing the inner walls of the gearbox 4 and the gearbox cover 5 to prevent the lubricating oil from leaking out of the lubricating oil chamber 69.

[0088] The flushing assembly includes a water trough 73 formed in the cavity of the machine head 6, a water hole 74 connecting the water trough 73 and the center hole 14 of the drill tail 12 is provided on the drill tail 12, and a flushing water port 75 connected to the water trough 73 is provided on the machine head 6. Since the machine head 6 is mounted on the gear box cover 5 by multiple bolts 10, it is convenient to adjust the orientation of the machine head 6 according to the position of the water supply system on the rock drilling rig; the flushing water injected through the flushing water port 75 enters the center hole 14 of the drill tail 12 through the water trough 73 and the water hole 74 and flows out.

[0089] Two U-shaped seals 76 are provided in the inner cavity of the machine head 6 located at the front and rear ends of the water trough 73, which are sealed with the shank 12 to prevent leakage of flushing water; and a leakage water cavity 77 is formed in the inner cavity of the machine head 6 at the rear end of the water trough 73, and a U-shaped seal 76 is also provided in the leakage water cavity 77 to prevent leakage of leaked water to the rear end; a plurality of drainage holes 78 are provided on the machine head 6, which are connected with the leakage water cavity 77 and are used to discharge the leaked water.

[0090] A copper sleeve 79 is embedded in the head cavity of the handpiece 6, along with a retaining ring 80 to prevent the sleeve 79 from falling off. The shank 12 is inserted through the copper sleeve 79. An air channel 81, connected to the air channel 18, is formed in the cavity of the handpiece 6, located outside the rear end of the copper sleeve 79. The copper sleeve 79 also has multiple air holes 82 that connect the air channel 81 and the gap between the copper sleeve 79 and the shank 12. Several air guide holes 83 are formed in the front baffle 64 to connect the air channel 18 with the gaps between the large gear 59, the gearbox cover 5, and the handpiece 6. Cooling and lubricating air enters the air guide holes 83 and the air channel 18 through the gap between the front baffle 64 and the handpiece 6. The cooling and lubricating air entering the air guide holes 83 then enters the gaps between the large gear 59, the gearbox cover 5, and the handpiece 6 before being blown out.

[0091] The following is a further description of the movement process of the impact piston 11. The direction of movement toward the nose 6 is taken as the displacement direction toward the front end, and the direction of movement toward the tail 1 is taken as the displacement direction toward the rear end.

[0092] Stroke, reversing

[0093] Phase 1: High-pressure hydraulic oil enters the rear high-pressure oil chamber 26 through the oil inlet on the machine base 1 and then enters the high-pressure oil channel 28. At this time, the valve body 20 seals the inner end of the high-pressure oil channel 28, and the high-pressure oil enters the left end chamber of the rear thrust channel 29, which is connected to the high-pressure oil channel 28. Since the forward thrust channel 41 is connected to the front oil return chamber 32, the middle oil return chamber 31, and the rear total oil return chamber 27 and is connected to the oil outlet on the machine base 1, there is no high-pressure oil in the right end chamber of the forward thrust channel 41.

[0094] Phase 2: High-pressure oil continuously flows into the left-end chamber of the rearward thrust passage 29, pushing the rearward thrust rod 46 to axially displace forward, which in turn pushes the valve body 20 to axially displace forward. After the valve body 20 displaces forward, it abuts against the rear end of the cylinder sleeve 21, closing the gap between the front end of the valve body 20 and the rear end of the cylinder sleeve 21, which originally connected the inner cavity of the valve body 20 and the rear end oil return chamber 30. At this point, the high-pressure oil passage 28 is connected to the inner cavity of the front end of the valve sleeve 19, allowing high-pressure oil to enter the inner cavity of the front end of the valve sleeve 19. Since the force-bearing area of ​​the force-bearing surface A50 is greater than the force-bearing area of ​​the force-bearing surface B53, the impact piston 11 is pushed to axially displace forward.

[0095] The third stage: During the forward movement of the impact piston 11, when the section B52 passes the front end surface of the inner platform stage D54, the high-pressure oil in the front high-pressure oil chamber 33 enters the front return oil chamber 32 and enters the right end chamber of the forward push channel 41. Since the diameter of the front push rod 47 is greater than the diameter of the rear push rod 46, under the condition of equal pressure, the front push rod 47 will push the valve body 20 to move toward the rear end until the valve body 20 closes the inner end of the high-pressure oil channel 28 again. At this time, the gap between the front end of the valve body 20 and the rear end of the cylinder liner 21 that originally connected the inner cavity of the valve body 20 and the rear end oil return cavity 30 is restored, so that the hydraulic oil located in the inner cavity of the valve body 20 can enter the rear end oil return cavity 30 through the gap, and then the force surface A50 is pressure-free, and the force surface C51 is affected by the high-pressure oil that enters the front end oil return cavity 32 through the front end high-pressure oil cavity 33, passes through the gap between the impact piston 11 and the cylinder liner 21 and acts on the force surface C51, causing the impact piston 11 to slow down until it hits the shank tail 12 and reverses direction. After being hit, the shank tail 12 will move toward the front end to impact the target object.

[0096] Return, reversing

[0097] The first stage: After the impact piston 11 is reversed, since only the force surface C51 is affected by the oil pressure, the impact piston 11 accelerates to the rear end. During the movement of the impact piston 11 to the rear end, when the cross section B52 passes the front end surface of the inner stage D54, only the force surface B53 is affected by the oil pressure. Since the area of ​​the force surface B53 is smaller than the area of ​​the force surface A50, the acceleration of the return movement of the impact piston 11 decreases at this time.

[0098] The second stage: as the impact piston 11 continues to move toward the rear end, when the force surface C51 passes over the front end surface of the intermediate oil return chamber 31, the high-pressure oil originally in the right end chamber of the forward thrust channel 41 enters the intermediate oil return chamber 31, reducing the force acting toward the rear end on the front thrust rod 47; and since high-pressure oil always enters the left end chamber of the backward thrust channel 29, it will push the valve body 20 toward the front end. Therefore, at this time, the valve body 20 moves toward the front end. When it reaches a certain position, a closed space filled with hydraulic oil will be formed by the impact piston 11, the valve sleeve 19, the valve body 20, and the cylinder sleeve 21, causing the impact piston 11 to brake.

[0099] When the valve body 20 continues to move forward, the inner end of the high-pressure oil channel 28 is opened, and the high-pressure oil enters the inner cavity of the valve body 20, acts on the force surface A50, and causes the impact piston 11 to reverse and start a new round of stroke movement.

[0100] Anti-air strike design

[0101] When the impact piston 11 moves to the front end to the force surface B53 and enters the inner stage E55, the front stage 49 of the impact piston 11 will form a closed space with the cylinder sleeve 21 and the piston guide sleeve 22, causing the impact piston 11 to brake, so that the distance the impact piston 11 moves to the front end is always within the designed stroke, and will not impact and damage other parts of the machine.

[0102] Stroke brake design

[0103] During the forward movement of the impact piston 11, when the section B52 passes the front end surface of the inner stage D54, the high-pressure oil in the front high-pressure oil chamber 33 enters the front return oil chamber 32 and enters the right end chamber of the forward push channel 41. Since the diameter of the front push rod 47 is greater than the diameter of the rear push rod 46, under equal pressure, the front push rod 47 will push the valve body 20 to move toward the rear end. In the process of the valve body 20 moving toward the rear end, the valve body 20 will close the inner end of the high-pressure oil channel 28, and at the same time, the gap between the front end of the valve body 20 and the rear end of the cylinder sleeve 21 that originally connected the inner cavity of the valve body 20 and the rear end return oil chamber 30 is in a closed state. At this time, a closed space will be formed between the impact piston 11, the valve sleeve 19, the valve body 20 and the cylinder sleeve 21. At this time, no high-pressure oil enters the closed space, even if the impact piston 11 is braked.

[0104] Return brake design

[0105] When the impact piston 11 moves to the rear end to the force surface C51 passing the front end surface of the intermediate oil return chamber 31, the forward push channel 41 will be connected to the intermediate oil return chamber 31 through the front end oil return chamber 32, the gap between the cylinder sleeve 21 and the impact piston 11, so that the front push rod 47 will lose the oil pressure effect, and the rear push rod 46 is always under the action of oil pressure, which causes the rear push rod 46 to push the valve body 20 to move to the front end. When the front end of the valve body 20 abuts against the rear end of the cylinder sleeve 21 to close the gap connecting the inner cavity of the valve body 20 and the rear end oil return chamber 30, the inner end of the high-pressure oil channel 28 is not opened. At this time, the front end inner cavity of the valve sleeve 19, the inner cavity of the valve body 20 and the front end of the cylinder sleeve 21 will form a closed space. Since the liquid is difficult to be compressed, the impact piston 11 is braked instantly at this time, realizing rapid braking of the return stroke of the impact piston 11, reversing, and increasing the impact frequency.

[0106] Valve sleeve 19 reversing push rod design

[0107] The rear push rod 46 slides left and right in the rear push channel 29 of the valve sleeve 19, the front push rod 47 slides left and right in the front push channel 41 of the cylinder sleeve 21, and the valve body 20 slides left and right in the space formed by the cylinder sleeve 21 and the valve sleeve 19. The left end of the valve body 20 contacts the right end of the rear push rod 46, and the right end of the valve body 20 contacts the left end of the front push rod 47. Since the left end chamber of the rear push channel 29 always has high-pressure oil entering, it pushes the valve body 20 to the front end, and the right end chamber of the front push channel 41 alternately has high pressure and low pressure. When high pressure occurs, since the diameter of the rear push rod 46 is smaller than the diameter of the front push rod 47, the valve body 20 is pushed to the rear end; conversely, when low pressure occurs, the valve body 20 is pushed to the front end.

[0108] Multi-section piston design

[0109] During the return stroke of the impact piston 11 (moving rearward), both ends of the front stage 49 are within the front high-pressure oil chamber 33. At this time, the impact piston 11 is subjected to the differential pressure between the annular surfaces Φ33:Φ38, accelerating the return stroke (toward the rear). When the cross section B52 passes the front surface of the inner stage D54, only the force-bearing surface B53 is within the front high-pressure oil chamber 33. At this time, the impact piston 11 is subjected to the differential pressure between the annular surfaces Φ35:Φ38, reducing the return stroke acceleration (toward the rear), increasing the braking speed of the impact piston 11 during the stroke, and boosting the rock drill frequency. Here, Φ33 refers to the diameter of the impact piston 11 between the front stage 49 and the rear stage 48, Φ38 refers to the diameter of the rear stage 48, and Φ35 refers to the diameter of the impact piston 11 at the front of the front stage 49. In actual application, the diameters of the impact piston 11 at various locations are not limited to the values ​​listed above, as long as they are compatible with the cylinder liner 21 and can achieve the above-mentioned objectives.

[0110] Leakage chamber design

[0111] The valve sleeve 19 has an oblique hole 43, connecting the rear leakage oil chamber 42 with the main oil return chamber. A through hole 45 in the cylinder sleeve 21 connects the front leakage oil chamber 44 with the leakage annular chamber 39. The leakage annular chamber 39 and the main oil return chamber are connected via an oil return passage 40. This ensures that the step seals 24 at both ends of the impact piston 11 always operate at low pressure (oil return pressure), thereby improving the service life of the seals.

[0112] Impact part and rotation part are designed independently

[0113] The impact part of the impact piston 11 and the rotating part of the shank 12 are designed independently, which is convenient for repair and maintenance.

[0114] The above is only a preferred embodiment of the present utility model patent. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present utility model patent. These improvements and modifications should also be regarded as the scope of protection of the present utility model patent.

Claims

1. A hydraulic rock drill, characterized in that: The machine body comprises a machine base, a cylinder body, an intermediate body, a gear box, a gear box cover and a machine head which are connected in sequence. An impact assembly is arranged in the machine base and the cylinder body; a rotary assembly is arranged in the gear box and the gear box cover; and a flushing assembly is formed in the machine head. The impact assembly forms a first chamber for accommodating the impact piston; the rotary assembly and the flushing assembly jointly form a second chamber for accommodating the shank tail, and a cooling and lubrication chamber connecting the first chamber and the second chamber is formed in the intermediate body; Hydraulic oil is introduced into the first chamber, and the impact piston can reciprocate along the central axis of the first chamber under the push of the hydraulic oil, and the head of the impact piston can pass through the first chamber into the cooling and lubricating chamber and hit the tail of the shank, causing the shank to move axially; The tail of the shank adapter is inserted into the rotary assembly and the rotary assembly drives the shank adapter to rotate forward or reverse along the central axis; A central hole extending toward the head of the shank is formed on the shank body, and the flushing assembly injects a flushing medium into the central hole; An air intake chamber is formed in the machine base, and an air intake port connected to the air intake chamber is opened at the rear end of the machine base; a central channel is formed on the impact piston to connect the air intake chamber and the cooling and lubricating air chamber; an air passage is formed in the die head to connect the shank, the gap between the rotary assembly and the die head, and the gap between the shank and the die head; The cooling and lubricating gas introduced into the air inlet chamber enters the cooling and lubricating cavity through the central channel of the impact piston, and passes through the shank, the gap between the rotary assembly and the machine head, the air outlet channel, and enters the gap between the head of the shank and the machine head and is blown out.

2. A hydraulic rock drill according to claim 1, characterized in that: The tail of the cylinder body is embedded in the front inner cavity of the machine base, the tail of the intermediate body is embedded in the front inner cavity of the cylinder body, the tail of the gear box is embedded in the front inner cavity of the intermediate body, and the tail of the machine head is embedded in the front inner cavity of the gear box cover; The impact assembly includes a valve sleeve, a valve body, a cylinder sleeve and an impact piston; The valve sleeve is embedded in the engine base and closes the air inlet chamber, with its head embedded in the rear end inner cavity of the cylinder body; the valve body is installed in the front end inner cavity of the valve sleeve; the cylinder sleeve is arranged in the cylinder body, with its tail abutting against the head of the valve sleeve, and its head abutting against the tail of the intermediate body; the inner cavity of the valve sleeve is connected to the inner cavity of the cylinder sleeve; the impact piston is installed in the inner cavity of the cylinder sleeve, and during the reciprocating motion, the tail end of the impact piston can pass through the valve sleeve and enter the air inlet chamber; The hydraulic oil pushes the valve body and the impact piston to reciprocate. When the valve body is displaced axially forward by a preset distance, the hydraulic oil pushes the impact piston forward; when the impact piston is displaced forward by a preset distance, the hydraulic oil pushes the valve body to be displaced axially backward; when the valve body is displaced axially backward by a preset distance, the hydraulic oil pushes the impact piston backward; when the impact piston is retracted by a preset distance, the hydraulic oil pushes the valve body to be displaced axially to the left, and this cycle repeats.

3. A hydraulic rock drill according to claim 2, characterized in that: An annular rear high-pressure oil chamber and a rear total oil return chamber are sequentially formed along the radial direction between the engine base and the valve sleeve, and between the engine base, the valve sleeve and the tail of the cylinder body. A rear end oil return cavity is formed between the inner cavity of the valve sleeve and the inner cavity of the cylinder sleeve and the valve body; The cylinder liner is radially formed with an annular middle oil return chamber, a front oil return chamber and a front high-pressure oil chamber in sequence from the rear to the front, and is isolated by an impact piston. The middle oil return chamber, the rear oil return chamber and the rear main oil return chamber are connected; The valve sleeve is provided with a plurality of high-pressure oil channels for connecting the rear high-pressure oil chamber with the inner cavity of the valve sleeve; The valve body closes the high-pressure oil channel. After the hydraulic oil is injected into the rear high-pressure oil chamber, it pushes the valve body to move axially forward to open the high-pressure oil channel. The rear high-pressure oil chamber is connected to the inner cavity of the valve sleeve. The hydraulic oil enters the inner cavity of the valve sleeve and pushes the impact piston to move axially forward. When the impact piston moves forward a preset distance, the front high-pressure oil chamber is connected to the front oil return chamber, and the hydraulic oil pushes the valve body to move axially backward to close the high-pressure oil channel. The impact piston completes the impact under the action of the hydraulic oil and retreats backward; When the impact piston retreats a preset distance, the front oil return chamber is connected with the middle oil return chamber, the rear oil return chamber, and the rear total oil return chamber; the high-pressure oil injected into the rear high-pressure oil chamber pushes the valve body to move axially forward to open the high-pressure oil channel so that the rear high-pressure oil chamber is connected with the inner cavity of the valve sleeve, and the hydraulic oil enters the inner cavity of the valve sleeve and pushes the impact piston to move axially forward, and the cycle repeats.

4. A hydraulic rock drill according to claim 3, characterized in that: A plurality of back-thrust passages are distributed axially and circumferentially in the head of the valve sleeve and are connected to the high-pressure oil passage and the rear end oil return chamber; A plurality of forward thrust passages are distributed axially and circumferentially in the rear end of the cylinder liner, communicating with the rear end oil return chamber and the front end oil return chamber; A rear push rod and a front push rod are respectively slidably arranged in the rear push channel and the front push channel for pushing the valve body axial displacement under the action of hydraulic oil, wherein the diameter of the front push rod is larger than that of the rear push rod; An accumulator is installed on the side of the engine base, and the liquid side of the accumulator is connected to the rear high-pressure oil chamber; and an oil inlet channel for connecting the rear high-pressure oil chamber and the front high-pressure oil chamber is formed on the valve body and the cylinder sleeve; An oil inlet communicated with the rear high-pressure oil chamber and an oil outlet communicated with the rear total return oil chamber are provided on the side of the machine base.

5. A hydraulic rock drill according to claim 3, characterized in that: A plurality of step seals are embedded in the rear end inner cavity of the valve sleeve to prevent the hydraulic oil from leaking to the rear end, and a sealing component is provided in the inner cavity of the abutting end of the cylinder body and the intermediate body to prevent the hydraulic oil from leaking to the front end; An annular rear end leakage oil chamber is formed in the rear end inner cavity of the valve sleeve located at the front end of the step seal; a front end leakage oil chamber is formed between the sealing assembly and the inner cavity of the cylinder body; The front leakage oil chamber is connected to the rear total oil return chamber; the rear leakage oil chamber is connected to the middle oil return chamber, and is connected to the rear total oil return chamber through the middle oil return chamber and the rear oil return chamber.

6. A hydraulic rock drill according to claim 1, characterized in that: The rotary assembly includes a cycloid motor, a pinion gear and a gear; The pinion is arranged in the upper cavity of the gear box, and needle bearings are arranged on the outer sides of both ends of the pinion. The pinion rotates relative to the upper cavity of the gear box through the needle bearings. The large gear is clamped in the gear box and meshes with the small gear. Conical bearings are provided on the outside of both ends of the large gear. The large gear rotates relative to the gear box through the conical bearings. The shank is inserted through the large gear and has a clearance fit with the large gear without any rotation; The cycloid motor is installed outside the upper cavity of the gearbox and is used to drive the small gear to rotate forward or reverse, thereby driving the large gear and the drill tail to rotate synchronously.

7. A hydraulic rock drill according to claim 6, characterized in that: The rotary assembly also includes a follower sleeve, a rear stop sleeve and a front stop sleeve; The follower sleeve is set in the front end inner cavity of the large gear. The shank is inserted through the follower sleeve. Along the length direction of the shank, teeth are formed around the shank. A tooth groove is formed in the inner cavity of the follower sleeve. The shank is engaged with the tooth groove of the follower sleeve to achieve non-rotational and clearance fit. A corresponding arc groove is formed around the outer surface of the follower sleeve and the front end inner cavity of the large gear and extends along the length direction of the follower sleeve, and a follower column is embedded in the corresponding arc groove, so that the large gear drives the follower sleeve to follow the movement through the follower column; The rear stop sleeve is set in the inner cavity of the large gear at the rear end of the follower sleeve, and is used to limit the rear axial displacement distance of the shank; the front stop sleeve is embedded in the rear end inner cavity of the machine head and abuts against the follower sleeve, follower column, large gear and gear box cover, and the maximum straight-line distance from the outer edge of the tooth to the horizontal center line of the shank is greater than the front end opening radius of the front stop sleeve, which is used to prevent the follower sleeve and follower column from moving forward and limit the forward axial displacement distance of the shank.

8. The hydraulic rock drill according to claim 6, characterized in that: The head of the large gear extends into the gear box cover, and a lubricating oil cavity is formed between the large gear and the small gear; A shaft seal is provided in the rear end inner cavity of the gearbox and the rear end inner cavity of the gearbox cover, which is in contact with the outer peripheral body of the corresponding end of the large gear and is used to prevent the lubricating oil in the lubricating oil cavity from leaking. A retaining ring is also embedded in the rear end inner cavity of the gearbox and the rear end inner cavity of the gearbox cover at the rear end of the shaft seal to prevent the displacement of the shaft seal. A sealing sleeve is provided outside the tapered bearing located outside the large gear head, which is in contact with and sealed against the inner wall of the gear box and the gear box cover to prevent leakage of lubricating oil in the lubricating oil cavity.

9. The hydraulic rock drill according to claim 1, characterized in that: The flushing assembly includes a water trough formed in the cavity of the handpiece, a water hole connecting the water trough and the center hole of the handpiece is opened on the shank, and a flushing water outlet connected to the water trough is opened on the handpiece; The flushing water injected through the flushing water inlet flows into the center hole of the shank through the water trough and water hole and flows out; Two U-shaped seals are provided in the inner cavity of the machine head located at the front and rear ends of the water trough, which are sealed with the shank tail to prevent leakage of flushing water; and a leakage water cavity is formed in the inner cavity of the machine head at the rear end of the water trough, and a U-shaped seal is also provided in the leakage water cavity to prevent leakage of leaked water to the rear end; a plurality of drainage holes are provided on the machine head, which are connected with the leakage water cavity and are used to discharge the leaked water.

10. The hydraulic rock drill according to claim 7, characterized in that: A copper sleeve is embedded in the head cavity of the machine head, and a retaining ring is embedded in the head cavity of the machine head to prevent the copper sleeve from falling off, and the shank is inserted through the copper sleeve; An air groove connected to the air passage is formed in the cavity of the handpiece located outside the rear end of the copper sleeve, and a plurality of air holes connecting the air groove and the gap between the copper sleeve and the shank are opened on the copper sleeve; Several air guide holes are provided on the front baffle sleeve for connecting the air passage with the large gear, gear box cover and the gap between the machine head; the cooling and lubricating air enters the air guide holes and the air passage through the gap between the front baffle sleeve and the machine head, and the cooling and lubricating air entering the air guide holes enters the gap between the large gear, gear box cover and the machine head and is blown out.

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