A hydraulic rock drill

Abstract

The present invention discloses a hydraulic rock drill comprising a body with a cavity, comprising a base, a cylinder, an intermediate body, a gearbox, a gearbox cover, and a drill head, all of which are fixed and sealed together in sequence. A piston is axially displaceable within the body, and a drill adapter is axially displaceable and rotatable relative to the body. The hydraulic rock drill utilizes a unique anti-runaway design, a stroke brake design, a return brake design, a valve sleeve reversing push rod design, a multi-section piston design, a leakage chamber design, independently designed impact and rotational sections, and a design that eliminates radial relative motion. These features effectively address the low power efficiency, short structural and component lifespan, and high vibration and noise levels of existing rock drills.

Description

Technical Field

[0001] The invention relates to a hydraulic rock drill and belongs 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] While the rock drill industry continues to develop, domestically produced hydraulic rock drills are still inefficient. For example, the power conversion efficiency of rear-chamber oil return rock drills is generally below 55%; some structures and parts have short service life, large vibrations during operation, and low energy transfer efficiency. Therefore, most rock drills rely on imports. Summary of the Invention

[0004] In order to solve the shortcomings of the existing technology, the present invention provides a hydraulic rock drill that is independently developed and designed. The rock drill has excellent power conversion efficiency, low vibration and noise, and can increase the service life of components and is easy to repair and maintain.

[0005] The technical solution adopted in the present invention is:

[0006] A hydraulic rock drill comprises a body with a cavity consisting of a base, a cylinder, an intermediate body, a gear box, a gear box cover and a head, which are fixed and sealed in sequence. The body is further provided with:

[0007] A valve and a cylinder body, the valve is arranged in the machine base, the cylinder body is arranged in the cylinder barrel, and a plurality of corresponding rear push rod channels and front push rod channels are evenly opened in one end where the valve and the cylinder body abut, and a rear push rod and a front push rod are slidably arranged in each rear push rod channel and each front push rod channel, and the diameter of the front push rod is larger than that of the rear push rod;

[0008] A piston having a central hole, horizontally extending through the valve and cylinder body, with its rear end located in the inner cavity of the base behind the valve and its front end extending into the lubricating air chamber at the front end of the intermediate body. The rods at both ends of the piston are respectively sealed with the valve and the intermediate body to form a closed space to prevent leakage of hydraulic oil. The piston is axially displaceable relative to the valve, cylinder body and intermediate body;

[0009] A valve sleeve is mounted on a piston located in the inner cavity of the front end of the valve and can be axially displaced under the action of oil pressure;

[0010] An oil inlet channel and an oil return channel are formed between the piston, valve sleeve and valve, cylinder body, machine base and cylinder barrel. An oil inlet P connected to the oil inlet channel and an oil outlet T connected to the oil return channel are opened on the front and rear sides of the machine base.

[0011] A shank, which is horizontally and rotatably disposed within the gearbox, the gearbox cover, and the handpiece and extends to the outside of the front end of the handpiece. When the piston is axially displaced forward by the hydraulic oil, it acts on the shank to cause axial displacement;

[0012] A transmission mechanism is disposed in a gear box, and a cycloid motor is fixedly disposed outside the gear box to drive the transmission mechanism to rotate the shank. A rear stop sleeve and a front stop sleeve are respectively disposed in the front end inner cavity of the transmission mechanism and the rear end inner cavity of the handpiece to limit the axial displacement distance of the shank.

[0013] A lubrication and cooling channel is formed between the inner cavity of the machine base on the rear side of the valve and the center hole of the piston, the intermediate body, the shank, the transmission mechanism, the rear stop sleeve, the front stop sleeve and the machine head. A flushing channel is formed between the shank and the machine head. The intermediate body has two lubrication air ports connected to the lubrication and cooling channels, and the machine head has a flushing water port connected to the flushing channel.

[0014] As a preferred embodiment of the present invention,

[0015] The valve, from back to front, forms a high-pressure oil chamber 1 with the engine base, and forms a total oil return chamber with the engine base and the cylinder barrel. The oil inlet P is connected to the high-pressure oil chamber 1, and the oil outlet T is connected to the total oil return chamber. The valve has multiple high-pressure oil channels connected to the inner cavity of the front end of the valve, among which multiple high-pressure oil channels are connected to the rear push rod channel.

[0016] The cylinder body and the front end of the valve form an oil return chamber 1, and from back to front, an oil return chamber 2, an inner ring groove, and a high-pressure oil chamber 2 are sequentially formed in the cylinder body. The oil return chamber 2 is connected to the oil return chamber 1 and the total oil return chamber, and the high-pressure oil chamber 2 is connected to the high-pressure oil chamber 1. A leakage annular chamber is formed in the cylinder body and the cylinder barrel at the front end of the high-pressure oil chamber 2. An oil return channel for connecting the leakage annular chamber and the oil return chamber 2 is provided in the cylinder body, and multiple front push rod channels are all connected to the inner ring groove;

[0017] The piston has a rear stage and a front stage. The rear stage of the piston is axially displaceable in the front inner cavity of the valve and the rear inner cavity of the cylinder body. The cylinder body has an inner stage D for separating the inner ring groove and the second high-pressure oil chamber, and an inner stage E for separating the second high-pressure oil chamber from the front inner cavity of the cylinder body. The front stage of the piston is axially displaceable in the inner stage D, the second high-pressure oil chamber, and the inner stage E of the cylinder body.

[0018] The high-pressure oil chamber 1, the high-pressure oil channel and the high-pressure oil chamber 2 form an oil inlet channel; the leakage chamber, the oil return chamber 2, the oil return chamber 1 and the total oil return chamber form an oil return channel.

[0019] As a preferred embodiment of the present invention,

[0020] The rear end of the rear stage of the piston forms a force surface A, and the front end forms a force surface C. The rear end of the front stage of the piston forms a cross-section B, and the front end forms a force surface B. The force area of the force surface A is larger than the force areas of the force surfaces C and B, and the diameter of the piston located between the force surface C and the cross-section B is larger than the diameter of the piston located behind the force surface A, and smaller than the diameter of the piston located in front of the force surface B.

[0021] As a preferred embodiment of the present invention, a front sealing seat for the piston to pass through and sealed with the piston is provided in the inner cavity at the rear end of the intermediate body, the valve and the front sealing seat in the intermediate body are sealed with the piston to form a closed space to prevent leakage of hydraulic oil, and a front copper sleeve for the piston to pass through is provided in the inner cavity at the front end of the cylinder body, and the front copper sleeve is sealed with the cylinder body.

[0022] As a preferred embodiment of the present invention, a piston rear end leakage chamber is provided in the rear end inner cavity of the valve, and the piston rear end leakage chamber is connected with the total return oil chamber through an inclined hole on the valve; a piston front end leakage chamber is formed at the front end of the front copper sleeve, the front sealing seat, and the front end inner cavity of the cylinder body, and the piston front end leakage chamber is connected with the leakage ring chamber through a through hole on the cylinder body.

[0023] As a preferred embodiment of the present invention, a dust ring for the piston to pass through is further provided at the front end of the front sealing seat, and a high-pressure accumulator is further provided on the machine base.

[0024] As a preferred embodiment of the present invention, the transmission mechanism includes:

[0025] A small gear is arranged in the cavity above the gear box, fixedly connected to the cycloid motor actuator shaft, and rotatably connected to the gear box through needle bearings arranged on the outer sides of both ends;

[0026] A sealing sleeve is arranged in the front end inner cavity of the gear box and the front end is embedded in the gear box cover, and is fixedly connected to the gear box and the gear box cover and seals;

[0027] A large gear is arranged in the cavity below the gearbox and meshes with the small gear. Both ends of the gearbox are inserted through the gearbox and the front end extends into the inner cavity of the gearbox cover. It is rotatably connected to the gearbox through two tapered bearings arranged on the outer circumference of both ends. The rear end of the shank is inserted into the inner cavity of the large gear and has a non-rotating, clearance fit.

[0028] The rear stop sleeve is arranged in the front end cavity of the large gear, and a limiting space is formed between the rear stop sleeve and the front stop sleeve. The drill tail passes through the rear stop sleeve and the front stop sleeve, and a limiting table is formed on the drill tail located in the limiting space.

[0029] As a preferred embodiment of the present invention, shaft seals are provided in the rear end inner cavity of the gear box and the rear end inner cavity of the gear box cover, which are respectively abutted against the outer peripheral bodies at both ends of the large gear, and retaining rings are provided in the rear end inner cavity of the gear box and the rear end inner cavity of the gear box cover located at the rear end of each shaft seal, which respectively cooperate with the rear end inner cavity of the gear box and the rear end inner cavity of the gear box cover to limit the corresponding shaft seals.

[0030] As a preferred embodiment of the present invention, the rear baffle has two symmetrical through holes, a plurality of support blocks for supporting the shank are formed around the inner surface of the rear baffle, and an air passage for lubricating gas to pass through and communicate with the through holes is formed between the plurality of support blocks, and a gas gap is formed between the surface of the rear baffle located at the outer end of the through hole and then milled flat to form an air gap with the inner cavity of the front section of the large gear;

[0031] There is an air gap between the front baffle sleeve and the rear baffle sleeve, and two air grooves corresponding to the through holes are formed on the front baffle sleeve;

[0032] A copper sleeve for the handpiece is provided in the inner cavity at the front end of the handpiece and is limited by a retaining ring. The inner wall of the copper sleeve for the handpiece is in contact with the outer periphery of the drill tail. A drill tail protection ring is provided at the end of the handpiece at the front end of the copper sleeve. A plurality of corresponding air holes are opened on the copper sleeve for the handpiece, and an inner air groove which is in communication with the air holes is formed in the copper sleeve for the handpiece.

[0033] An air ring is formed on the cross section of the inner cavity at the rear end of the handpiece, and an air groove is formed in the inner cavity at the front end of the handpiece, which is connected to the air hole. The air ring and the air groove are connected through a lubricating air channel formed in the handpiece.

[0034] The inner cavity of the valve base, the center hole of the piston, the lubricating air chamber, the air passage, the through hole, the first air gap, the second air gap, the air groove, the air ring, the lubricating air passage, the air groove, the air hole and the inner air groove form a lubrication and cooling passage.

[0035] As a preferred embodiment of the present invention, a water trough is formed in the inner cavity of the die head between the copper sleeve and the gas ring, and a plurality of U-shaped seals for forming a seal with the shank are provided in the inner cavity of the die head at the front and rear ends of the water trough;

[0036] The flushing water outlet in the machine head is connected with the water trough, and a water hole is opened on the shank to communicate with the water trough and the inner cavity of the front end of the shank. The water trough and the water hole form a flushing channel.

[0037] The beneficial effects of the present invention are:

[0038] 1. The unique anti-airstrike design ensures that the rightward movement distance of the piston is always within the designed stroke, which will not damage other parts of the machine. The unique stroke braking design allows the piston to reverse direction while striking the drill tail, achieving the best impact power and frequency. The unique return braking design allows for rapid braking and reversal of the piston during the return stroke, thereby increasing the impact frequency.

[0039] 2. The unique valve sleeve reversing push rod design solves the problem of large leakage of the reversing valve of the rear chamber oil return rock drill and improves the efficiency of the rock drill;

[0040] 3. The unique multi-section piston design realizes variable speed movement of the piston return stroke. The front section Φ33:Φ38 annular surface pressure outputs force to accelerate the return stroke, while the rear section Φ35:Φ38 annular surface differential pressure reduces the return acceleration, increases the piston braking speed during the stroke, and improves the frequency of the rock drill.

[0041] 4. The unique leakage chamber design ensures that the step seals at both ends of the piston are always in a low-pressure (return oil pressure) working state, which can extend the service life of the seals;

[0042] 5. The impact part and rotary part are designed independently, which is convenient for repair and maintenance. By replacing the front rotary part, the rock drill can be simply transformed into a hydraulic impactor.

[0043] 6. The design has no radial relative motion. The tail of the drill bit adopts an external hexagonal design, and the large gear and rear stop sleeve adopt an internal hexagonal design. When used together, the large gear drives the drill bit to rotate, and the drill bit drives the rear stop sleeve to rotate, which can extend the service life of the parts.

[0044] 7. Small vibration and noise. The optimal power efficiency reaches 73% when the impact pressure is 140 bar, and the impact power is the largest when the impact pressure is 160 bar. The power conversion efficiency is significantly improved, which significantly improves the efficiency of the rock drill. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 A three-dimensional schematic diagram of a hydraulic rock drill provided by the present invention;

[0046] Figure 2 A cross-sectional view of the hydraulic rock drill provided by the present invention;

[0047] Figure 3 A cross-sectional view of a piston section rock drill according to the present invention;

[0048] Figure 4 It is a cross-sectional view of the piston step surface section and the cylinder inner stage section structure;

[0049] Figure 5 is a three-dimensional schematic diagram of a valve;

[0050] Figure 6 is a cross-sectional view of the valve;

[0051] Figure 7 It is a three-dimensional schematic diagram of the cylinder;

[0052] Figure 8 is a cross-sectional view of the cylinder;

[0053] Figure 9 is a cross-sectional view of the intermediate body;

[0054] Figure 10 It is a cross-sectional view of the transmission structure;

[0055] Figure 11 This is a cross-sectional view of the nose;

[0056] Figure 12 It is a three-dimensional schematic diagram of the large gear;

[0057] Figure 13 It is a three-dimensional schematic diagram of the shank;

[0058] Figure 14 It is a three-dimensional schematic diagram of the rear baffle;

[0059] Figure 15 It is a three-dimensional schematic diagram of the front guard cover;

[0060] Figure 16 It is a structural diagram of the first stage during the stroke and reversing process;

[0061] Figure 17 It is a schematic diagram of the structure of the second stage during the stroke and reversing process;

[0062] Figure 18 It is a structural diagram of the third stage during the stroke and reversing process;

[0063] Figure 19 This is a schematic diagram of the structure of the first stage during the return and reversing process;

[0064] Figure 20 This is a schematic diagram of the second stage structure during the return and reversing process;

[0065] Figure 21 This is a schematic diagram of the structure during air-defense and stroke braking;

[0066] Figure 22 This is a schematic diagram of the structure during return braking;

[0067] Figure 23 It is a structural schematic diagram of a multi-section piston in one state;

[0068] Figure 24 It is a structural diagram of the multi-section piston in another state;

[0069] Figure 25 This is a schematic diagram of the lubrication and cooling channels;

[0070] Figure 26 Schematic diagram of the flushing channel;

[0071] Figure 27 This is a comparison test result chart;

[0072] Figure 28 This is the relationship between piston displacement and time under 80 bar impact pressure;

[0073] Figure 29 This is the relationship between piston displacement and time under 100 bar impact pressure;

[0074] Figure 30 This is the relationship between piston displacement and time under 120 bar impact pressure;

[0075] Figure 31 This is the relationship between piston displacement and time under 140 bar impact pressure;

[0076] Figure 32 This is the relationship between piston displacement and time under 160 bar impact pressure;

[0077] Figure 33 It is a three-dimensional schematic diagram of the valve and valve sleeve;

[0078] The main reference numerals in the figures have the following meanings:

[0079] 1. Engine base, 2. Cylinder, 3. Intermediate body, 4. Gearbox, 5. Gearbox cover, 6. Machine head, 7. Piston, 8. Boring tail, 9. Seal sleeve, 10. Positioning pin, 11. Long screw assembly, 12. Short screw assembly, 13. Valve, 14. Cylinder body, 15. Front copper sleeve, 16. Front sealing seat, 17. Dust ring, 18. Step seal, 19. High-pressure oil chamber 1, 20. Total return oil chamber, 21. Oil inlet P, 22. Oil outlet T, 23. High-pressure oil channel, 24, rear push rod channel, 25, return oil chamber 1, 26, return oil chamber 2, 27, inner ring groove, 28, high-pressure oil chamber 2, 29, channel 1, 30, channel 2, 31, channel 3, 32, sinking cavity, 33, oil passage, 34, leakage ring chamber, 35, return oil channel, 36, front push rod channel, 37, piston rear end leakage chamber, 38, inclined hole, 39, piston front end leakage chamber, 40, through hole, 41, rear push rod, 4 2. Front push rod, 43. Valve sleeve, 44. Back stage, 45. Front stage, 46. Load surface A, 47. Load surface C, 48. Section B, 49. Load surface B, 50. Inner stage D, 51. Inner stage E, 52. High-pressure accumulator, 53. Cycloid motor, 54. Back stop sleeve, 55. Front stop sleeve, 56. Pinion, 57. Gear, 58. Needle roller bearing, 59. Tapered bearing, 60. Limit table, 61. Shaft seal , 62, retaining ring, 63, through hole, 64, support block, 65, air passage, 66, air gap one, 67, air gap two, 68, air groove, 69, head copper sleeve, 70, drill tail protection ring, 71, air hole, 72, inner air groove, 73, air ring, 74, air groove, 75, lubrication air channel, 76, lubrication air port, 77, water trough, 78, U-shaped seal, 79, water hole, 80, flushing water port, 81, lubrication air chamber. DETAILED DESCRIPTION

[0080] The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0081] like Figure 1-33 As shown: This embodiment is a hydraulic rock drill, see Figure 1 、 Figure 2 As shown, it includes a body with a cavity composed of a base 1, a cylinder 2, an intermediate body 3, a gear box 4, a gear box cover 5 and a head 6 that are fixedly connected in sequence, a piston 7 that can be axially displaced in the body, and a shank 8 that can be axially displaced and rotated relative to the body.

[0082] The rear end of the cylinder barrel 2 is inserted into the front end of the base 1, the rear end of the intermediate body 3 is inserted into the front end of the cylinder barrel 2, and the rear end of the gear box 4 is inserted into the front end of the intermediate body 3, and the abutting surfaces of the two adjacent components are sealed by sealing rings. A sealing sleeve 9 is provided in the inner cavity of the front end of the gear box 4, and the rear end of the gear box cover 5 is embedded in the sealing sleeve 9. Similarly, the sealing sleeve 9 and the gear box 4 and the gear box cover 5 contact surfaces are all sealed by sealing rings. The base 1, cylinder barrel 2, intermediate body 3, gear box 4, sealing sleeve 9, gear box cover 5 and the machine head 6 are positioned by multiple positioning pins 10 in the abutting ends. The base 1, cylinder barrel 2, intermediate body 3, gear box 4 and gear box cover 5 are assembled into one by four long screw assemblies 11, and the machine head 6 is fixed to the gear box cover 5 by four short screw assemblies 12, thereby forming the machine body.

[0083] See also Figure 3 、 Figure 4 As shown, a valve 13 is provided in the inner cavity of the machine base 1, and a cylinder body 14 is provided in the cylinder barrel 2 located between the valve 13 and the intermediate body 3. The valve 13 and the cylinder body 14 are also positioned by a locating pin. A front copper sleeve 15 is clamped in the front end inner cavity of the cylinder body 14, and a front sealing seat 16 is clamped in the rear end inner cavity of the intermediate body 3. The piston 7 sequentially penetrates the valve 13, the cylinder barrel 2, the front copper sleeve 15, and the front sealing seat 16 and extends to the lubricating air chamber 81 at the front end of the intermediate body 3. A dust ring 17 for the piston 7 to penetrate is also clamped at the front end of the front sealing seat 16.

[0084] The contact surfaces between the valve 13 and the machine base 1, between the cylinder body 14 and the cylinder barrel 2, between the cylinder body 14 and the intermediate body 3 and the front copper sleeve 15, and between the contact surfaces between the intermediate body 3 and the front sealing seat 16 are all sealed by sealing rings; and step seals 18 for sealing are installed in the two grooves in the valve 13 and the two grooves in the front sealing seat 16 to prevent leakage of hydraulic oil.

[0085] The valve 13 and the machine base 1 form a high-pressure oil chamber 19, and form a total return oil chamber 20 with the machine base 1 and the cylinder 2. The machine base 1 is provided with an oil inlet P21 connected to the high-pressure oil chamber 19 and an oil outlet T22 connected to the total return oil chamber 20. The valve 13 has a plurality of high-pressure oil channels 23 connected to the inner cavity at the front end of the valve 13, and four rear push rod channels 24 are provided in the front end of the valve 13, and the four rear push rod channels 24 are correspondingly connected to four of the high-pressure oil channels 23.

[0086] See also Figure 3-Figure 9 、 Figure 33As shown, an oil return chamber 1 25 is formed at the front end of the cylinder body 14 and the valve 13, and from back to front, an oil return chamber 2 26, an inner ring groove 27, and a high-pressure oil chamber 2 28 are formed in sequence in the cylinder body 14. The oil return chamber 26 is connected to the oil return chamber 1 25 through a hole 1 29 in the cylinder body 14, and is connected to the total oil return chamber 20 through a hole 2 30 in the valve 13 that is connected to the hole 1 29 and a hole 31 that is connected to the hole 2 30. Two sinking chambers 32 that are connected to the high-pressure oil chamber 2 28 are formed between the middle section of the cylinder body 14 and the cylinder barrel 2. There are multiple oil passages that are connected to each other in the front valve 13 and the rear end of the cylinder body 14. Channel 33, one end of the multiple oil passages 33 is respectively connected to multiple high-pressure oil channels 23, and the other end is connected to the corresponding sink cavity 32, and then the high-pressure oil chamber 2 28 is connected to the high-pressure oil chamber 1 19; a leakage annular chamber 34 is also formed between the cylinder body 14 and the cylinder barrel 2 at the front end of the high-pressure oil chamber 28, and a return oil channel 35 for connecting the leakage annular chamber 34 and the return oil chamber 2 26 is provided in the cylinder body 14, and the return oil channel 35 is corresponding to the channel 1 29; the rear end cylinder body 14 has a plurality of front push rod channels 36 corresponding to the rear push rod channels 24 respectively and the front end is connected to the inner ring groove 27.

[0087] The rear end inner cavity of the valve 13 is provided with a piston rear end leakage chamber 37, which is located in front of the step seal 18 on the valve 13, and is connected to the total oil return chamber 20 through an inclined hole 38 on the valve 13; the front end of the front copper sleeve 15 and the front sealing seat 16, as well as the front end inner cavity of the cylinder body 14 form a piston front end leakage chamber 39, which is connected to the leakage ring chamber 34 through a through hole 40 on the cylinder body 14.

[0088] A rear push rod 41 and a front push rod 42 are respectively embedded in each rear push rod channel 24 and each front push rod channel 36. The diameter of the front push rod 42 is larger than that of the rear push rod 41, and the rear push rod 41 and the front push rod 42 can move freely in the corresponding rear push rod channel 24 and the front push rod channel 36 (clearance fit); a valve sleeve 43 is provided in the front end inner cavity of the valve 13, and the valve sleeve 43 can move freely in the front end inner cavity of the valve 13 (clearance fit). In the initial state, the rear end of the valve sleeve 43 It abuts against the inner cavity of the front end of the valve 13 to close the inner end of the high-pressure oil channel 23, and the front end of the valve sleeve 43 and the rear end of the cylinder body 14 have a gap connecting the inner cavity of the valve sleeve 43 and the return oil chamber 25; a convex portion is formed on the outer periphery of the front end of the valve sleeve 43, the rear push rod 41 abuts against the rear end surface of the convex portion, and the front push rod 42 abuts against the front end surface of the convex portion. Under the action of hydraulic oil, the valve sleeve 43 can be axially displaced relative to the piston 7 in the space formed by the inner cavity of the front end of the valve 13 and the inner cavity of the rear end of the cylinder body 14.

[0089] The piston 7 has a rear stage 44 and a front stage 45. The rear end of the rear stage 44 of the piston 7 forms a force surface A46, and the front end forms a force surface C47. The rear end of the front stage 45 of the piston 7 forms a cross-section B48, and the front end forms a force surface B49. The force area of the force surface A46 is larger than the force areas of the force surfaces C47 and B49; and the rear stage 44 of the piston 7 can be axially displaced in the front end inner cavity of the valve 13 and the rear end inner cavity of the cylinder body 14. The cylinder body 14 has an inner stage D50 for separating the inner ring groove 27 and the high-pressure oil chamber 2 28, and an inner stage E51 for separating the high-pressure oil chamber 28 and the front end inner cavity of the cylinder body 14. The front stage 45 of the piston 7 can be axially displaced in the inner stage D50, the high-pressure oil chamber 28 and the inner stage E51 of the cylinder body 14.

[0090] See also Figure 1 As shown, a high-pressure accumulator 52 is provided at the rear end of the machine base 1, and a high-pressure diaphragm is placed in the upper end groove of the machine base 1. Then the outer cover is screwed into the machine base 1, and the nitrogen charging connector and the plug are screwed into the outer cover. The machine base 1 has a plurality of inner holes for connecting the upper end groove with the high-pressure oil chamber 19. The high-pressure accumulator 52 is a common structure in existing rock drills and can be used as a liquid compensation device to eliminate pulsation and reduce noise, absorb hydraulic shock, and serve as a hydraulic air spring.

[0091] See also Figure 10-15 As shown, the shank 8 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 8 extends into the lubricating air chamber 81 of the intermediate body 3 and leaves a certain distance from the front end of the piston 7 to be struck. When the piston 7 is axially displaced forward by the action of hydraulic oil, it acts on the shank 8 to cause axial displacement.

[0092] A transmission mechanism is provided in the gear box 4, and a cycloidal motor 53 is fixedly provided outside the gear box 4 to drive the transmission mechanism to rotate the shank 8. A rear stop sleeve 54 and a front stop sleeve 55 for limiting the axial displacement distance of the shank 8 are respectively provided in the front end inner cavity of the transmission mechanism and the rear end inner cavity of the head 6.

[0093] The transmission mechanism includes a small gear 56, a large gear 57 and the above-mentioned sealing sleeve 9. The small gear 56 is arranged in the cavity above the gear box 4, is fixedly connected to the executive shaft of the cycloid motor 53, and is rotatably connected to the gear box 4 through needle bearings 58 arranged on the outside of both ends; the sealing sleeve 9 is arranged in the inner cavity of the front end of the gear box 4 and the front end is embedded in the gear box cover 5, and is fixedly connected to the gear box 4 and the gear box cover 5 and sealed; the large gear 57 is arranged in the cavity below the gear box 4 and meshes with the small gear 56, and its two ends are inserted through the gear box 4 and the front end extends into the inner cavity of the gear box cover 5, and is rotatably connected to the gear box 4 through two tapered bearings 59 arranged on the outer circumference of both ends. The rear end of the shank tail 8 is inserted into the inner cavity of the large gear 57 without rotation and clearance fit. In actual application, the rear end of the shank tail 8 adopts an external hexagonal design, and the inner hole of the large gear 57 adopts an internal hexagonal design, so that the shank tail 8 and the large gear 57 have no radial relative movement.

[0094] The rear stop sleeve 54 is arranged in the front end cavity of the large gear 57. A limiting space is formed between the rear stop sleeve 54 and the front stop sleeve 55. The drill tail 8 passes through the rear stop sleeve 54 and the front stop sleeve 55. A limiting table 60 is formed on the drill tail 8 located in the limiting space.

[0095] In the rear end inner cavity of the gear box 4 and the rear end inner cavity of the gear box cover 5, there are provided shaft seals 61 which are respectively in contact with the outer periphery of the two ends of the large gear 57, and in the rear end inner cavity of the gear box 4 and the rear end inner cavity of the gear box cover 5 located at the rear end of each shaft seal 61, there are provided retaining rings 62 which respectively cooperate with the rear end inner cavity of the gear box 4 and the rear end inner cavity of the gear box cover 5 to limit the corresponding shaft seals 61.

[0096] The cycloid motor 53 drives the small gear 56 to move and then drives the large gear 57 to rotate. Since the rear end of the drill tail 8 is inserted into the inner cavity of the large gear 57 without rotation and clearance, the drill tail 8 can be driven to rotate when the large gear 57 rotates.

[0097] There are two symmetrical through holes 63 in the rear baffle sleeve 54, and a plurality of support blocks 64 for supporting the drill tail 8 are formed around the inner surface of the rear baffle sleeve 54. In actual application, the plurality of support blocks 64 constitute an inner hexagonal design, so that the drill tail 8 and the rear baffle sleeve 54 have no radial relative movement, and an air passage 65 for lubricating gas to pass through and connected to the through holes 63 is formed between the plurality of support blocks 64. The surface of the rear baffle sleeve 54 at the outer end of the through hole 63 is milled flat to form an air gap 1 66 with the inner cavity of the front section of the large gear 57; an air gap 2 67 is formed between the front baffle sleeve 55 and the rear baffle sleeve 54, and two air grooves 68 corresponding to the through holes 63 are formed on the front baffle sleeve 55; a head copper sleeve 69 is provided in the inner cavity at the front end of the head 6 for limiting by the retaining ring 62, the inner wall of the head copper sleeve 69 is in contact with the outer periphery of the drill tail 8, and is fixed on the head copper sleeve A shank protection ring 70 is provided at the end of the machine head 6 at the front end of 69, and a plurality of corresponding air holes 71 are opened on the machine head copper sleeve 69, and an internal air groove 72 which is connected to the air holes 71 is formed in the machine head copper sleeve 69; an air ring 73 is formed on the cross section of the inner cavity at the rear end of the machine head 6, and an air groove 74 which is connected to the air holes 71 is formed in the inner cavity at the front end of the machine head 6, and the air ring 73 is connected to the air groove 74 through a lubrication air channel 75 formed in the machine head 6; the inner cavity of the machine base 1 on the rear side of the valve 13, the piston center hole, the lubrication air chamber, the air channel 65, the through hole 63, the air gap 1 66, the air gap 2 67, the air groove 68, the air ring 73, the lubrication air channel 75, the air groove 74, the air holes 71 and the internal air groove 72 form a lubrication and cooling channel, and the front and rear sides of the intermediate body 3 have two lubrication air ports 76 which are connected to the lubrication and cooling channels.

[0098] A water trough 77 is formed in the inner cavity of the machine head 6 between the machine head copper sleeve 69 and the air ring 73, and a plurality of U-shaped seals 78 for forming a seal with the drill tail 8 are provided in the inner cavity of the machine head 6 at the front and rear ends of the water trough 77; a flushing water outlet 80 in the machine head 6 is connected with the water trough 77, and a water hole 79 is provided on the drill tail 8, which is connected with the water trough 77 and the inner cavity at the front end of the drill tail 8. The water trough 77 and the water hole 79 form a flushing channel, and the machine head 6 has a flushing water outlet 80 connected with the flushing channel.

[0099] Stroke, reversing

[0100] Phase 1: See Figure 16 As shown, high-pressure hydraulic oil enters the high-pressure oil chamber 19 through the oil inlet P21 on the machine base 1, and the high-pressure oil enters the high-pressure oil channel 23. At this time, the valve sleeve 43 closes the inner end of the high-pressure oil channel 23, and the high-pressure oil enters the left end chamber of the rear push rod channel 24 connected to the high-pressure oil channel 23. Since the front push rod channel 36 is connected to the return oil chamber 26, the return oil chamber 1, and the total return oil chamber 20 and is connected to the oil outlet T22 on the machine base 1, there is no high-pressure oil in the right end chamber of the front push rod channel 36.

[0101] Phase II: See Figure 17 As shown, high-pressure oil always enters the chamber at the left end of the rear push rod channel 24 to push the rear push rod 41 to move axially to the right, and then push the valve sleeve 43 to move axially to the right. After the valve sleeve 43 moves to the right, it abuts against the rear end of the cylinder body 14, and then the gap between the front end of the valve sleeve 43 and the rear end of the cylinder body 14 that originally connected the inner cavity of the valve sleeve 43 and the return oil chamber 25 is closed. At this time, the high-pressure oil channel 23 and the inner cavity of the front end of the valve 13 are connected, so that the high-pressure oil can enter the inner cavity of the front end of the valve 13, and then because the force area of the force surface A46 is greater than the force area of the force surface B49, the piston 7 is pushed to move axially to the right.

[0102] Phase 3: See Figure 18 As shown, during the forward movement of the piston 7, when the cross section B48 passes the front end surface of the inner stage D50, the high-pressure oil in the high-pressure oil chamber 28 enters the inner ring groove 27 and enters the right end chamber of the front push rod channel 36. Since the diameter of the front push rod 42 is larger than that of the rear push rod 41, under the condition of equal pressure, the front push rod 42 will push the valve sleeve 43 to move left until the valve sleeve 43 closes the inner end of the high-pressure oil channel 23 again. At this time, the front end of the valve sleeve 43 and the rear end of the cylinder body 14 are originally The gap between the inner cavity of the connecting valve sleeve 43 and the oil return chamber 1 25 is restored, so that the hydraulic oil located in the inner cavity of the valve sleeve 43 can enter the oil return chamber 1 25 through the gap, and then the force-bearing surface A46 is pressure-free. The force-bearing surface C47 is acted upon by the high-pressure oil that enters the inner ring groove 27 through the high-pressure oil chamber 28 and acts on the force-bearing surface C47 through the gap between the piston 7 and the cylinder body 14, so that the piston 7 slows down until it hits the shank tail 8 and changes direction. After the impact, the shank tail 8 will move to the right to hit the target object.

[0103] Return, reversing

[0104] First stage: After the piston 7 is reversed, since only the force-bearing surface C47 is affected by the oil pressure, the piston 7 accelerates to move to the left. During the process of the piston 7 moving to the left, when the cross section B48 passes the front end surface of the inner stage D50, see Figure 19 As shown, at this time, only the force-bearing surface B49 is affected by the oil pressure. Since the area of the force-bearing surface B49 is smaller than the area of the force-bearing surface A46, the return motion acceleration of the piston 7 is reduced.

[0105] Phase II: See Figure 20As shown, in the process of the piston 7 continuing to move to the left, when the force surface C47 passes over the front end surface of the return oil chamber 26, the high-pressure oil originally in the right end chamber of the front push rod channel 36 enters the return oil chamber 26, so that the leftward force on the front push rod 42 is reduced; and because there is always high-pressure oil entering the left end chamber of the rear push rod channel 24, it will push the valve sleeve 43 to the right. Therefore, the valve sleeve 43 moves to the right at this time. When it reaches a certain position, a closed space filled with hydraulic oil will be formed by the piston 7, the valve 13, the valve sleeve 43, and the cylinder body 14, causing the piston 7 to brake.

[0106] When the valve sleeve 43 continues to move to the right, the inner end of the high-pressure oil channel 23 is opened, and the high-pressure oil enters the inner cavity of the front end of the piston 7 and the inner cavity of the valve sleeve 43, acting on the force surface A46, causing the piston 7 to reverse and start a new round of stroke movement.

[0107] Anti-air strike design

[0108] See also Figure 21 As shown, when the piston 7 moves to the right to the force surface B49 and enters the inner stage E51, the front stage 45 of the piston 7 will form a closed space with the cylinder body 14 and the front copper sleeve 15, causing the movement of the piston 7 to be braked, so that the distance the piston 7 moves to the right is always within the designed stroke and will not impact or damage other parts of the machine.

[0109] Stroke brake design

[0110] See also Figure 18 As shown, during the forward movement of the piston 7, when the section B48 passes the front end surface of the inner stage D50, the high-pressure oil in the high-pressure oil chamber 28 enters the inner ring groove 27 and enters the right end chamber of the front push rod channel 36. Since the diameter of the front push rod 42 is greater than the diameter of the rear push rod 41, under the condition of equal pressure, the front push rod 42 will push the valve sleeve 43 to move to the left. During the movement of the valve sleeve 43 to the left, the valve sleeve 43 will close the inner end of the high-pressure oil channel 23, and at the same time, the gap between the front end of the valve sleeve 43 and the rear end of the cylinder body 14 that originally connected the inner cavity of the valve sleeve 43 and the return oil chamber 25 is in a closed state. At this time, a closed space will be formed between the piston 7, the valve 13, the valve sleeve 43 and the cylinder body 14. At this time, no high-pressure oil enters the closed space, even if the piston 7 is braked.

[0111] Return brake design

[0112] See also Figure 22As shown, when the piston 7 moves to the left until the force surface C47 passes the front end surface of the return oil chamber 26, the front push rod channel 36 will be connected to the return oil chamber 26 through the inner ring groove 27, the gap between the cylinder body 14 and the piston 7, so that the front push rod 42 will lose the effect of oil pressure, while the rear push rod 41 is always under the effect of oil pressure, which causes the rear push rod 41 to push the valve sleeve 43 to move to the right. When the front end of the valve sleeve 43 abuts the rear end of the cylinder body 14 to close the gap connecting the inner cavity of the valve sleeve 43 and the return oil chamber 1 25, the inner end of the high-pressure oil channel 23 is not opened. At this time, the inner cavity of the front end of the valve 13, the inner cavity of the valve sleeve 43 and the front end of the cylinder body 14 will form a closed space. Since the liquid is difficult to be compressed, the piston 7 is braked instantly at this time, realizing rapid braking of the piston 7 return stroke, reversing, and increasing the impact frequency.

[0113] Valve sleeve reversing push rod design

[0114] The rear push rod 41 slides left and right in the rear push rod channel 24 of the valve 13, the front push rod 42 slides left and right in the front push rod channel 36 of the cylinder body 14, and the valve sleeve 43 slides left and right in the space formed by the cylinder body 14 and the valve 13. The left end of the valve sleeve 43 contacts the right end of the rear push rod 41, and the right end of the valve sleeve 43 contacts the left end of the front push rod 42. Since the left end chamber of the rear push rod channel 24 always has high-pressure oil entering, the valve sleeve 43 is pushed to the right, and the right end chamber of the front push rod channel 36 alternates between high pressure and low pressure. When high pressure occurs, since the diameter of the rear push rod 41 is smaller than the diameter of the front push rod 42, the valve sleeve 43 is pushed to the left; conversely, when low pressure occurs, the valve sleeve 43 is pushed to the right. According to relevant information (book title: "Foreign Hydraulic Rock Drills", Coal Industry Press, pages 60-61), when the gap sealing length is 10 mm, the leakage oil pressure is reduced by 50%, and when the gap sealing length is 20 mm, the leakage oil pressure is reduced by 90%. During the entire movement process, the gap sealing length of the front push rod 42 and the rear push rod 41 is greater than 20 mm, and only a small amount of high-pressure oil leaks, which solves the problem of large leakage of the return oil rock drill reversing valve 13 and improves the efficiency of the rock drill.

[0115] Multi-section piston design

[0116] See also Figure 23 As shown, when the piston 7 returns (the piston 7 moves to the left), when both end surfaces of the front stage 45 are in the high-pressure oil chamber 28, the piston 7 is subjected to the pressure difference between the Φ33:Φ38 annular surfaces and accelerates the return stroke (to the left); see Figure 24 As shown, when the section B48 passes the front end surface of the inner stage D50, only the force-bearing surface B49 is in the high-pressure oil chamber 28. At this time, the piston 7 is subjected to the differential pressure between the Φ35:Φ38 annular surfaces, which reduces the return acceleration (to the left) and increases the braking speed of the piston 7 during the stroke, thereby increasing the frequency of the rock drill.

[0117] Leakage chamber design

[0118] See also Figure 6 、 Figure 8 As shown, the valve 13 has an inclined hole 38, which connects the leakage chamber 37 at the rear end of the piston with the total oil return chamber 20, and a through hole 40 is provided on the cylinder body 14, which connects the leakage chamber 39 at the front end of the piston with the leakage ring chamber 34, and the leakage ring chamber 34 and the total oil return chamber 20 are connected through the return oil channel 35, which makes the step seals 18 at both ends of the piston 7 always in a low-pressure (return oil pressure) working state, thereby improving the service life of the seals.

[0119] Impact part and rotation part are designed independently

[0120] The impact part of the piston 7 and the rotating part of the drill tail 8 are designed independently, which is convenient for repair and maintenance. By replacing the front rotating part, the rock drill can be simply transformed into a hydraulic impactor.

[0121] Design without radial relative motion Figure 12 、 Figure 13 、 Figure 14 As shown, the tail of the drill tail 8 adopts an external hexagonal design, and the large gear 57 and the rear stop sleeve 54 both adopt an internal hexagonal design. When used together, the large gear 57 drives the drill tail 8 to rotate, and the drill tail 8 drives the rear stop sleeve 54 of the drill tail 8 to rotate, thereby improving the service life of the parts.

[0122] Lubrication and cooling design

[0123] See also Figure 25 As shown, the cooling lubricating air is connected to the lubricating air port 76, and after filling the lubricating air chamber 81, it enters the inner cavity of the machine base 1 on the rear side of the valve 13 from the center hole of the piston, and passes through the gap between the shank 8 and the large gear 57 to reach the air passage 65 of the rear baffle sleeve 54, and then passes through the through hole 63, the air gap 1 66, the air gap 2 67, and the air groove 68 on the front baffle sleeve 55 to enter the air ring 73, and then passes through the lubricating air channel 75, the air groove 74, and the air hole 71 to enter the inner air groove 72 in the head copper sleeve 69, thereby providing lubrication and cooling for the relative movement between the shank 8 and the large gear 57, the rear baffle sleeve 54, the front baffle sleeve 55, and the head copper sleeve 69, and can also cool the piston 7.

[0124] Flush design

[0125] See also Figure 26As shown, the front baffle 55 is inserted into the drill head 6, and the drill tail 8 passes through the front baffle 55, is sealed by multiple U-shaped seals 78, and then passes through the drill head copper sleeve 69. Flushing water enters the water channel 77 inside the drill head 6 through the flushing water port 80 on the drill head 6. Because the drill tail 8 is sealed with U-shaped seals 78 on both sides, the incoming water can only enter the water channel 79 on the drill tail 8 and be discharged to the outside of the rock drill. The drill tail 8 can move left and right, with its forward position limited by the front baffle 55 and its rearward position limited by the rear baffle 54.

[0126] The hydraulic rock drill provided by the present invention was subjected to comparative tests under the conditions of impact pressures of 80, 100, 120, 140 and 160 bar, and various performance data during the test were recorded. The test results are shown in FIG. Figure 27 As shown in the figure, the relationship between piston displacement and time under different impact pressures is shown in the figure. Figure 28-32 shown.

[0127] Comparative test results show that the hydraulic rock drill provided by the present invention achieves optimal power efficiency when the impact pressure is 140 bar, and has the maximum impact power when the impact pressure is 160 bar; and has low noise and vibration.

[0128] The above is only a preferred embodiment of the patent of the present invention. 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 patent of the present invention. These improvements and modifications should also be regarded as the scope of protection of the patent of the present invention.

Claims

1. A hydraulic rock drill, comprising a body with a cavity consisting of a base, a cylinder, an intermediate body, a gear box, a gear box cover and a head, which are fixed and sealed in sequence, characterized in that: The body is also provided with: A valve and a cylinder body, the valve is arranged in the machine base, the cylinder body is arranged in the cylinder barrel, and a plurality of corresponding rear push rod channels and front push rod channels are evenly opened in one end where the valve and the cylinder body abut, and a rear push rod and a front push rod are slidably arranged in each rear push rod channel and each front push rod channel, and the diameter of the front push rod is larger than that of the rear push rod; A piston having a central hole, horizontally extending through the valve and cylinder body, with its rear end located in the inner cavity of the base behind the valve and its front end extending into the lubricating air chamber at the front end of the intermediate body. The rods at both ends of the piston are respectively sealed with the valve and the intermediate body to form a closed space to prevent leakage of hydraulic oil. The piston is axially displaceable relative to the valve, cylinder body and intermediate body; A valve sleeve is mounted on a piston located in the inner cavity of the front end of the valve and can be axially displaced under the action of oil pressure; An oil inlet channel and an oil return channel are formed between the piston, valve sleeve and valve, cylinder body, machine base and cylinder barrel. An oil inlet P connected to the oil inlet channel and an oil outlet T connected to the oil return channel are opened on the front and rear sides of the machine base. A shank, which is horizontally and rotatably disposed within the gearbox, the gearbox cover, and the handpiece and extends to the outside of the front end of the handpiece. When the piston is axially displaced forward by the hydraulic oil, it acts on the shank to cause axial displacement; A transmission mechanism is disposed in a gear box, and a cycloid motor is fixedly disposed outside the gear box to drive the transmission mechanism to rotate the shank. A rear stop sleeve and a front stop sleeve are respectively disposed in the front end inner cavity of the transmission mechanism and the rear end inner cavity of the handpiece to limit the axial displacement distance of the shank. A lubrication and cooling channel is formed between the inner cavity of the machine base on the rear side of the valve and the center hole of the piston, the intermediate body, the shank, the transmission mechanism, the rear stop sleeve, the front stop sleeve and the machine head. A flushing channel is formed between the shank and the machine head. The intermediate body has two lubrication air ports connected to the lubrication and cooling channels, and the machine head has a flushing water port connected to the flushing channel.

2. A hydraulic rock drill according to claim 1, characterized in that: described The valve, from back to front, forms a high-pressure oil chamber 1 with the engine base, and forms a total oil return chamber with the engine base and the cylinder barrel. The oil inlet P is connected to the high-pressure oil chamber 1, and the oil outlet T is connected to the total oil return chamber. The valve has multiple high-pressure oil channels connected to the inner cavity of the front end of the valve, among which multiple high-pressure oil channels are connected to the rear push rod channel. The cylinder body and the front end of the valve form an oil return chamber 1, and from back to front, an oil return chamber 2, an inner ring groove, and a high-pressure oil chamber 2 are sequentially formed in the cylinder body. The oil return chamber 2 is connected to the oil return chamber 1 and the total oil return chamber, and the high-pressure oil chamber 2 is connected to the high-pressure oil chamber 1. A leakage annular chamber is formed in the cylinder body and the cylinder barrel at the front end of the high-pressure oil chamber 2. An oil return channel for connecting the leakage annular chamber and the oil return chamber 2 is provided in the cylinder body, and multiple front push rod channels are all connected to the inner ring groove; The piston has a rear stage and a front stage. The rear stage of the piston is axially displaceable in the front inner cavity of the valve and the rear inner cavity of the cylinder body. The cylinder body has an inner stage D for separating the inner ring groove and the second high-pressure oil chamber, and an inner stage E for separating the second high-pressure oil chamber from the front inner cavity of the cylinder body. The front stage of the piston is axially displaceable in the inner stage D, the second high-pressure oil chamber, and the inner stage E of the cylinder body. The high-pressure oil chamber 1, the high-pressure oil channel and the high-pressure oil chamber 2 form an oil inlet channel; the leakage chamber, the oil return chamber 2, the oil return chamber 1 and the total oil return chamber form an oil return channel.

3. A hydraulic rock drill according to claim 2, characterized in that: described The rear end of the rear stage of the piston forms a force surface A, and the front end forms a force surface C. The rear end of the front stage of the piston forms a cross-section B, and the front end forms a force surface B. The force area of the force surface A is larger than the force areas of the force surfaces C and B, and the diameter of the piston located between the force surface C and the cross-section B is larger than the diameter of the piston located behind the force surface A, and smaller than the diameter of the piston located in front of the force surface B.

4. A hydraulic rock drill according to claim 2, characterized in that: A front sealing seat for the piston to pass through and sealed with the piston is provided in the inner cavity at the rear end of the intermediate body. The front sealing seat in the valve and the intermediate body is sealed with the piston to form a closed space to prevent leakage of hydraulic oil. A front copper sleeve for the piston to pass through is provided in the inner cavity at the front end of the cylinder body. The front copper sleeve is sealed with the cylinder body.

5. A hydraulic rock drill according to claim 4, characterized in that: A piston rear end leakage chamber is provided in the rear end inner cavity of the valve, and the piston rear end leakage chamber is connected to the total oil return chamber through an inclined hole on the valve; a piston front end leakage chamber is formed between the front end of the front copper sleeve, the front sealing seat, and the front end inner cavity of the cylinder body, and the piston front end leakage chamber is connected to the leakage ring chamber through a through hole on the cylinder body.

6. A hydraulic rock drill according to claim 4, characterized in that: A dustproof ring for the piston to penetrate is also provided at the front end of the front sealing seat, and a high-pressure accumulator is also provided on the machine base.

7. A hydraulic rock drill according to claim 2, characterized in that: The transmission mechanism comprises: A small gear is arranged in the cavity above the gear box, fixedly connected to the cycloid motor actuator shaft, and rotatably connected to the gear box through needle bearings arranged on the outer sides of both ends; A sealing sleeve is arranged in the front end inner cavity of the gear box and the front end is embedded in the gear box cover, and is fixedly connected to the gear box and the gear box cover and seals; A large gear is arranged in the cavity below the gearbox and meshes with the small gear. Both ends of the gearbox are inserted through the gearbox and the front end extends into the inner cavity of the gearbox cover. It is rotatably connected to the gearbox through two tapered bearings arranged on the outer circumference of both ends. The rear end of the shank is inserted into the inner cavity of the large gear and has a non-rotating, clearance fit. The rear stop sleeve is arranged in the front end cavity of the large gear, and a limiting space is formed between the rear stop sleeve and the front stop sleeve. The drill tail passes through the rear stop sleeve and the front stop sleeve, and a limiting table is formed on the drill tail located in the limiting space.

8. A hydraulic rock drill according to claim 7, characterized in that: Shaft seals are provided in the rear end inner cavity of the gearbox and the rear end inner cavity of the gearbox cover, which are respectively in contact with the outer periphery of the two ends of the large gear. In addition, retaining rings are provided in the rear end inner cavity of the gearbox and the rear end inner cavity of the gearbox cover located at the rear end of each shaft seal, which cooperate with the rear end inner cavity of the gearbox and the rear end inner cavity of the gearbox cover to limit the corresponding shaft seals.

9. The hydraulic rock drill according to claim 7, characterized in that: The rear baffle has two symmetrical through holes, and a plurality of support blocks for supporting the drill tail are formed around the inner surface of the rear baffle, and an air passage for lubricating gas to pass through and communicate with the through holes is formed between the plurality of support blocks. The surface of the rear baffle at the outer end of the through hole is milled flat to form an air gap between the rear baffle and the inner cavity of the front section of the large gear. There is an air gap between the front baffle sleeve and the rear baffle sleeve, and two air grooves corresponding to the through holes are formed on the front baffle sleeve; A copper sleeve for the handpiece is provided in the inner cavity at the front end of the handpiece and is limited by a retaining ring. The inner wall of the copper sleeve for the handpiece is in contact with the outer periphery of the drill tail. A drill tail protection ring is provided at the end of the handpiece at the front end of the copper sleeve. A plurality of corresponding air holes are opened on the copper sleeve for the handpiece, and an inner air groove which is in communication with the air holes is formed in the copper sleeve for the handpiece. An air ring is formed on the cross section of the inner cavity at the rear end of the handpiece, and an air groove is formed in the inner cavity at the front end of the handpiece, which is connected to the air hole. The air ring and the air groove are connected through a lubricating air channel formed in the handpiece. The inner cavity of the valve base, the center hole of the piston, the lubricating air chamber, the air passage, the through hole, the first air gap, the second air gap, the air groove, the air ring, the lubricating air passage, the air groove, the air hole and the inner air groove form a lubrication and cooling passage.

10. A hydraulic rock drill according to claim 9, characterized in that: A water trough is formed in the inner cavity of the die head between the copper sleeve and the gas ring, and a plurality of U-shaped seals for forming a seal with the shank are provided in the inner cavity of the die head at the front and rear ends of the water trough; The flushing water outlet in the machine head is connected with the water trough, and a water hole is opened on the shank to communicate with the water trough and the inner cavity of the front end of the shank. The water trough and the water hole form a flushing channel.

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