Self-checking structure for rock drill and rock drill thereof

Abstract

The utility model relates to a self-checking structure for a rock drill and the rock drill with the self-checking structure. The piston is used for impacting the bit shank; the self-checking valve is used for detecting the running state; the cavity comprises a main cavity and a self-checking cavity; the main cavity comprises an offside cavity and a working cavity; the two sides of the self-checking cavity and the self-checking valve form a second front side pressed cavity and a second rear side pressed cavity respectively. An oil inlet normal pressure oil way and an offside signal oil way are arranged on the box body, the oil inlet normal pressure oil way is communicated with the front side pressed cavity II, and the two ends of the offside signal oil way are respectively communicated with the offside cavity and the rear side pressed cavity II; the piston comprises a rod body and a protruding ring protruding out of the rod body. When the self-checking valve abuts against the tail end of the self-checking cavity, the rock drill operates normally; when the self-checking valve abuts against the front end of the self-checking cavity, the rock drill operates abnormally. The self-checking structure for the rock drill and the rock drill with the self-checking structure have the advantages that the abnormal working state of the rock drill is detected through the self-checking valve.

Description

Technical Field

[0001] The utility model relates to the technical field of engineering machinery, in particular to a self-checking structure for a rock drill and the rock drill. Background Art

[0002] Rock drilling rigs are widely used in various working conditions such as rock mining and tunneling. As an important core component of the rig, the performance matching of the hydraulic rock drill directly affects the operating efficiency of the rig. Therefore, the rational selection of performance parameters during the use of the hydraulic rock drill is particularly critical. Due to the uneven rock structure causing rock cavities or soft soil structures, the impact energy demand for rock breaking in the corresponding working conditions is reduced. In order to ensure the increase in impact speed, the impact speed can be increased by reducing the impact energy and increasing the impact frequency; and due to improper operation, hole opening, and rod unloading operations, the actual impact energy of the rock drill needs to be effectively reduced to reduce damage to parts. At present, the main adjustment method is to take the initiative to adjust and reduce the pressure of the impact system, which requires real-time attention from personnel and has higher requirements for personnel. Utility Model Content

[0003] An object of the present application is to provide a self-checking structure for a rock drill and the rock drill thereof, which can automatically detect the operating status.

[0004] The technical solution adopted in this application is: a self-checking structure for a rock drill, comprising:

[0005] A box body having a cavity;

[0006] Piston, used to impact the shank;

[0007] Self-check valve, used to check the operating status;

[0008] The cavity comprises a main cavity and a self-check cavity, the piston is slidably arranged in the main cavity, and the self-check valve is slidably arranged in the self-check cavity; the main cavity comprises an offside cavity and a working cavity, the diameter of the offside cavity is smaller than the diameter of the working cavity; the two sides of the self-check cavity respectively form two front pressure cavities and two rear pressure cavities with the self-check valve; the box body is provided with an oil inlet normal pressure oil circuit and an offside signal oil circuit, the oil inlet normal pressure oil circuit is connected with the two front pressure cavities, and the two ends of the offside signal oil circuit are respectively connected with the offside cavity and the two rear pressure cavities; the piston comprises a rod body and a convex ring protruding from the rod body, and the convex ring cooperates with the offside cavity; when the self-check valve abuts against the end of the self-check cavity, the rock drill operates normally; when the self-check valve abuts against the front end of the self-check cavity, the rock drill operates abnormally.

[0009] In some embodiments of the present application, the two sides of the self-inspection cavity respectively form a front pressure cavity and a rear pressure cavity with the self-inspection valve; a balancing oil channel is provided on the self-inspection valve, and the balancing oil channel connects the front pressure cavity and the rear pressure cavity.

[0010] In some embodiments of the present application, a reversing valve is also included. The reversing valve is used to change the oil circuit to make the piston reversing movement. The self-checking valve can control the reversing time of the reversing valve.

[0011] Furthermore, it also includes an oil inlet and an oil return port; the main cavity also includes a rear cavity; a front cavity oil circuit and a rear cavity oil circuit are provided on the box body, the front cavity oil circuit is connected to the working cavity, and the rear cavity oil circuit is connected to the rear cavity; the A port of the reversing valve is connected to the front cavity oil circuit, the B port of the reversing valve is connected to the rear cavity oil circuit, the P port of the reversing valve is connected to the oil inlet, and the T port of the reversing valve is connected to the oil return port.

[0012] Furthermore, the two sides of the self-inspection cavity are respectively connected with the self-inspection valve to form three front pressure chambers and three rear pressure chambers; the box body is provided with a first reversing push valve oil circuit and a second reversing push valve oil circuit, the first reversing push valve oil circuit is respectively connected with the three front pressure chambers and the left oil port of the reversing valve, and the second reversing push valve oil circuit is respectively connected with the rear chamber and the right oil port of the reversing valve; the self-inspection valve is provided with a third reversing push valve oil channel, and the two ends of the third reversing push valve oil channel are respectively connected with the three front pressure chambers and the main cavity.

[0013] Furthermore, it also includes an oil leakage port, and a first oil leakage channel and a second oil leakage channel are provided on the box body; the two ends of the first oil leakage channel are respectively connected to the oil leakage port and the rear pressure three chambers; the two ends of the second oil leakage channel are respectively connected to the oil leakage port and the rear chamber.

[0014] In some embodiments of the present application, a first step is provided on the self-test valve, and an inner cavity cooperating with the first step is provided on the two front pressure chambers; one end of the oil inlet normal pressure oil circuit is arranged on the inner cavity; when the first step enters the inner cavity, a gap is provided between the first step and the cavity wall of the inner cavity close to the two front pressure chambers.

[0015] In some embodiments of the present application, the self-checking valve is annular and is arranged coaxially with the piston.

[0016] The self-checking structure for a rock drill obtained by the utility model has the following advantages:

[0017] 1. It can realize the coordinated control of impact energy and impact frequency. In normal working state, the impact parameters are selected according to the main working conditions and work normally. The rock drill maintains the design parameter high impact and low frequency gear, outputs high impact energy and low impact frequency, and ensures working efficiency; when encountering special working conditions, when the rock drill needs to reduce the impact energy, it automatically adjusts to the low impact and high frequency gear, outputs low impact energy and high impact frequency, reduces the loss of parts and ensures working efficiency;

[0018] 2. The rock drill automatically detects according to the operating status. When special working conditions occur, the self-check valve automatically switches to the low-impact and high-frequency gear position, without manual operation, which is efficient and fast;

[0019] 3. It can ensure that the working efficiency of the rock drill is not affected while ensuring the normal design parameters. When the rock drill automatically switches to the low-impact and high-frequency gear, the corresponding soft rock operation efficiency is higher, which is of great significance to the improvement of the overall rock drilling efficiency;

[0020] 4. No additional external oil circuit is required, and the automatic gear adjustment function of the rock drill can be directly upgraded.

[0021] A rock drill comprises the above-mentioned self-checking structure for the rock drill. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the structure of Embodiment 1 of the present utility model;

[0023] Figure 2 This is a schematic diagram of the structure of the abnormal working state of Example 1 of the utility model;

[0024] Figure 3 This is a schematic diagram of the structure of the piston retreating in an abnormal working state of Example 1 of the utility model;

[0025] Figure 4 It is a structural schematic diagram of the self-checking valve of Example 1 of the utility model;

[0026] Figure 5 yes Figure 1 The enlarged view of the C part in FIG.

[0027] Figure 6 yes Figure 5 Enlarged view of part D in .

[0028] In the figure: 1, box body; 11, oil inlet normal pressure oil circuit; 12, offside signal oil circuit; 13, front chamber oil circuit; 14, rear chamber oil circuit; 15, first reversing push valve oil circuit; 16, second reversing push valve oil circuit; 17, first leakage oil channel; 18, second leakage oil channel; 2, cavity; 21, main cavity; 211, offside cavity; 212, working cavity; 213, rear cavity; 22, self-test cavity; 221, two pressure-bearing cavities on the front side; 222, two pressure-bearing cavities on the rear side; 223, one pressure-bearing cavity on the front side; 224, one pressure-bearing cavity on the rear side cavity; 225, three pressure-bearing cavities on the front side; 226, three pressure-bearing cavities on the rear side; 227, inner cavity; 228, gap; 3, piston; 31, rod body; 32, convex ring; 4, self-test valve; 41, balance oil channel; 42, third reversing push valve oil channel; 43, first step; 44, first surface 44 on the front side; 45, second surface on the front side; 46, third surface on the front side; 47, first surface on the rear side; 48, second surface on the rear side; 49, third surface on the rear side; 5, reversing valve; 6, oil inlet; 7, oil return port; 8, leakage port. DETAILED DESCRIPTION

[0029] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined purpose of the utility model, the specific implementation method, structure, characteristics and effects of the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments.

[0030] Embodiment 1:

[0031] This embodiment provides a self-checking structure for a rock drill, such as Figure 1 , Figure 5 As shown, including:

[0032] A box body 1 having a cavity 2;

[0033] Piston 3, used for impacting the shank end;

[0034] Self-check valve 4, used to check the running status;

[0035] The cavity 2 includes a main cavity 21 and a self-checking cavity 22, the piston 3 is slidably arranged in the main cavity 21, and the self-checking valve 4 is slidably arranged in the self-checking cavity 22; the main cavity 21 includes an offside cavity 211 and a working cavity 212, the diameter of the offside cavity 211 is smaller than the diameter of the working cavity 212; the two sides of the self-checking cavity 22 form a front pressure chamber 221 and a rear pressure chamber 222 with the self-checking valve 4 respectively; the box body 1 is provided with an oil inlet normal pressure oil circuit 11 and an offside signal oil circuit 1 2, the oil inlet normal pressure oil circuit 11 is connected with the front side pressure chamber 221, and the two ends of the offside signal oil circuit 12 are respectively connected with the offside chamber 211 and the rear side pressure chamber 222; the piston 3 includes a rod body 31 and a convex ring 32 protruding from the rod body 31, and the convex ring 32 cooperates with the offside chamber 211; when the self-check valve 4 is in contact with the end of the self-check chamber 22, the rock drill operates normally; when the self-check valve 4 is in contact with the front end of the self-check chamber 22, the rock drill operates abnormally. Under normal working conditions, the pressure area at the front end of the self-check valve 4 is greater than the pressure area at the rear end of the self-check valve 4, and the oil pressure at the front end of the self-check valve 4 is greater than the oil pressure at the rear end of the self-check valve 4; under abnormal working conditions, the oil pressure at the rear end of the self-check valve 4 is greater than the oil pressure at the front end of the self-check valve 4. In this embodiment, the end of the piston 3 that works by impact is the front end. The front side two pressurized chambers 221 and the rear side two pressurized chambers 222 can be used for deceleration and braking protection of the forward and backward movement of the self-checking valve 4 .

[0036] Under the abnormal working state, the piston 3 is offside, and the convex ring 32 enters the offside cavity 211. The outer surface of the convex ring 32 cooperates with the cavity wall of the offside cavity 211, so that the offside cavity 211 becomes a dead cavity. After the convex ring 32 further extends into the offside cavity 211, the oil pressure in the offside cavity 211 increases, and is transported to the rear pressurized second cavity 222 through the offside signal oil circuit 12, so that the pressure on the rear end of the self-check valve 4 increases, while the oil inlet pressure of the normal pressure oil circuit 11 remains unchanged, so that the force on the rear end of the self-check valve 4 is greater than the force on the front end of the self-check valve 4, and the self-check valve 4 starts to move toward the front end until it abuts against the front end of the self-check cavity 22, thereby realizing the detection of the abnormal working state.

[0037] In order to balance the pressure, the two sides of the self-test cavity 22 respectively form a front pressure cavity 223 and a rear pressure cavity 224 with the self-test valve 4; the self-test valve 4 is provided with a balancing oil passage 41, which connects the front pressure cavity 223 and the rear pressure cavity 224. The front pressure chamber 223 alternates between being connected to the working chamber 212 and forming a dead chamber, that is, when the front pressure chamber 223 and the rod body 31 are in the same vertical axial section, the front pressure chamber 223 and the working chamber 212 are connected, and when they are in the same vertical axial section with the convex ring 32, the front pressure chamber 223 becomes a dead chamber; the rear pressure chamber 224 alternates between being connected to the working chamber 212 and forming a dead chamber, that is, when the rear pressure chamber 224 and the front end rod body 31 are in the same vertical axial section, the rear pressure chamber 224 and the working chamber 212 are connected, and when they are in the same vertical axial section with the convex ring 32, the rear pressure chamber 224 becomes a dead chamber; the design of the balancing oil passage 41 can balance the pressure on both sides.

[0038] In order to adjust the gear position, a reversing valve 5 is also included, which is used to change the oil circuit to make the piston 3 reversing movement, and the self-checking valve 4 can control the reversing time of the reversing valve 5. By controlling the reversing time of the reversing valve 5 through the self-checking valve 4, the stroke of the piston 3 can be changed.

[0039] For reliable operation, Figure 2 , Figure 3As shown, it also includes an oil inlet 6 and an oil return port 7; the main cavity 21 also includes a rear cavity 213; the box body 1 is provided with a front cavity oil circuit 13 and a rear cavity oil circuit 14, the front cavity oil circuit 13 is connected to the working cavity 212, and the rear cavity oil circuit 14 is connected to the rear cavity 213; the A port of the reversing valve 5 is connected to the front cavity oil circuit 13, the B port of the reversing valve 5 is connected to the rear cavity oil circuit 14, the P port of the reversing valve 5 is connected to the oil inlet 6, and the T port of the reversing valve 5 is connected to the oil return port 7. In this embodiment, the reversing valve 5 adopts a two-position four-way hydraulically controlled reversing valve. The oil inlet 6 is used to output high-pressure oil, and the oil return port 7 is used for oil recovery; the working chamber 212 and the rear chamber 213 are arranged on opposite sides of the box body 1; the front chamber oil circuit 13 is used to inject high-pressure oil into the working chamber 212, and the rear chamber oil circuit 14 is used to inject high-pressure oil into the rear chamber 213; when the reversing valve 5 is in the left-side connecting state, the rear chamber oil circuit 14 is connected with the oil inlet 6; when the reversing valve 5 is in the right-side connecting state, the front chamber oil circuit 13 is connected with the oil inlet 6.

[0040] In order to ensure reliable reversing of the reversing valve 5, the two sides of the self-checking chamber 22 are respectively formed with the self-checking valve 4 with three front pressure chambers 225 and three rear pressure chambers 226; the box body 1 is provided with a first reversing push valve oil circuit 15 and a second reversing push valve oil circuit 16, the first reversing push valve oil circuit 15 is respectively connected to the three front pressure chambers 225 and the left oil port of the reversing valve 5, and the second reversing push valve oil circuit 16 is respectively connected to the rear chamber 213 and the right oil port of the reversing valve 5; the self-checking valve 4 is provided with a third reversing push valve oil passage 42, and the two ends of the third reversing push valve oil passage 42 are respectively connected to the three front pressure chambers 225 and the main cavity 21. When the piston 3 is in the retracted state, there is a gap between the rod body 31 and the cavity wall of the main cavity 21, so that the working cavity 212 is connected to the self-checking cavity 22, so that the third reversing push valve oil passage 42 is connected to the working cavity 212. The first reversing push valve oil circuit 15 is connected with high-pressure oil to push the reversing valve 5, so that the reversing valve 5 is in a left-side connected state; the second reversing push valve oil circuit 16 is connected with high-pressure oil to push the reversing valve 5, so that the reversing valve 5 is in a right-side connected state; the third reversing push valve oil channel 42 is used to connect the front side pressurized three chambers 225 and the main chamber 21.

[0041] In order to reduce the oil interference in the dead space, it also includes a leakage oil port 8, and the housing 1 is provided with a first leakage oil channel 17 and a second leakage oil channel 18; the two ends of the first leakage oil channel 17 are respectively connected to the leakage oil port 8 and the rear pressure three chambers 226; the two ends of the second leakage oil channel 18 are respectively connected to the leakage oil port 8 and the rear chamber 213. The first leakage oil channel 17 can be used for oil leakage after the rear pressure three chambers 226 become a dead space to prevent the oil from affecting the movement of the self-checking valve 4; the second leakage oil channel 18 can be used for oil leakage in the middle section of the main chamber 21 to prevent the oil from affecting the movement of the piston 3 and ensure smooth movement of the piston 3. The first leakage oil channel 17 uses a small diameter pore. At the end of the backward movement of the self-checking valve 4, the flow rate of the first leakage oil channel 17 increases, the braking force is established, and the self-checking valve 4 is braked. Protection.

[0042] In order to set the deceleration brake protection for the self-check valve 4 to move forward and backward, such as Figure 6 As shown, the self-checking valve 4 is provided with a first step 43, and the front side pressure chamber 221 is provided with an inner cavity 227 that cooperates with the first step 43; one end of the oil inlet normal pressure oil circuit 11 is arranged on the inner cavity 227; when the first step 43 enters the inner cavity 227, a gap 228 is arranged between the first step 43 and the cavity wall of the inner cavity 227 close to the front side pressure chamber 221. The inner cavity 227 is adjacent to the front side pressure chamber 223. The design of the first step 43 is used to change the pressure area; when the self-checking valve 4 moves forward, the front side pressure chamber 221 can be used for deceleration and braking protection. When the first step 43 enters the inner cavity 227, the front side pressure chamber 221 becomes a dead cavity, and the oil inside it will affect the movement of the self-checking valve 4, and the design of the gap 228 can discharge the oil in the front side pressure chamber 221, and at the same time realize the establishment of braking force.

[0043] In order to ensure reliable installation of the self-checking valve 4, the self-checking valve 4 is annular and coaxially arranged with the piston 3. The self-checking valve 4 is sleeved on the piston 3.

[0044] In this embodiment, Figure 4 As shown, the self-test valve 4 includes a front first surface 44, a front second surface 45, and a front third surface 46 arranged in sequence at the front end, and a rear first surface 47, a rear second surface 48, and a rear third surface 49 arranged in sequence at the rear end; the front first surface 44, the front second surface 45, and the front third surface 46 are arranged in a step-like shape; the rear first surface 47, the rear second surface 48, and the rear third surface 49 are arranged in a step-like shape; the front first surface 44 and the cavity wall of the self-test cavity 22 are arranged in a step-like shape. The front side first pressure chamber 223 is formed; the front side second surface 45 and the cavity wall of the self-inspection cavity 22 form the front side second pressure chamber 221; the front side third surface 46 and the cavity wall of the self-inspection cavity 22 form the front side third pressure chamber 225; the rear side first surface 47 and the cavity wall of the self-inspection cavity 22 form the rear side first pressure chamber 224; the rear side second surface 48 and the cavity wall of the self-inspection cavity 22 form the rear side second pressure chamber 222; the rear side third surface 49 and the cavity wall of the self-inspection cavity 22 form the rear side third pressure chamber 226. The force on the front side first surface 44 is Af1; the force on the front side second surface 45 is Af2; the force on the front side third surface 46 is Af3; the force on the rear side first surface 47 is Ah1; the force on the rear side second surface 48 is Ah2; the force on the rear side third surface 49 is Ah3; and the force on the first step 43 is Af4. The total area of ​​the front first surface 44 , the front second surface 45 and the surface on the first step 43 facing the front end is greater than the total area of ​​the rear first surface 47 and the rear second surface 48 .

[0045] A normal striking depth S is reserved between the front end of the convex ring 32 and the front end of the working cavity 212 to ensure that the convex ring 32 does not enter the offside cavity 211 under normal working conditions, which is a condition for determining whether the working state is normal or not. The setting of the S value is related to the setting of the force bearing area on the self-checking valve 4. The minimum S value is the distance from the front end of the convex ring 32 to the edge of the offside cavity 211.

[0046] During normal operation, the reversing valve 5 is initially in the left-side connected state, and the high-pressure oil enters the rear chamber 213 through the rear chamber oil circuit 14, so that the oil pressure at the rear end of the piston 3 is greater than the oil pressure at the front end of the piston 3, and the piston 3 accelerates forward; after the piston 3 impacts in place, the rear chamber 213 is connected with the second reversing push valve oil circuit 16, and the high-pressure oil pushes the reversing valve 5 to the right-side connected state through the second reversing push valve oil circuit 16, and the high-pressure oil enters the working chamber 212 through the front chamber oil circuit 13, so that the oil pressure at the front end of the piston 3 is greater than the oil pressure at the rear end of the piston 3. pressure, the piston 3 makes a return acceleration motion backward; at the same time, the total area of ​​the front first surface 44, the front second surface 45 and the surface facing the front end on the first step 43 is larger than the total area of ​​the rear first surface 47 and the rear second surface 48, so Af1+Af2+Af4>Ah1+Ah2, the self-check valve 4 will be pressed to the end of the self-check chamber 22 at any position, so the normal working state of the rock drill is always the high-impact and low-frequency gear initially designed, and the parameter changes will not be caused by adding the self-check valve 4, and the self-check valve 4 will have a longer service life without action.

[0047] During abnormal operation, the piston 3 moves forward a greater distance, and the convex ring 32 enters the offside cavity 211, forming a dead cavity in the offside cavity 211. As the piston 3 continues to move forward, the pressure in the offside cavity 211 increases rapidly, and then the pressure of the rear pressure cavity 222 increases rapidly through the offside signal oil circuit 12. Although the high-pressure pressure area on the front side of the self-check valve 4 is larger than the high-pressure pressure area on the rear side at this time, since the front side pressure is less than or equal to the oil inlet pressure, and the pressure of the rear pressure cavity 222 is much greater than the oil inlet pressure at this time, the self-check valve 4 can move toward the front end of the self-check cavity 22 until the front side. At this time, the piston 3 makes a return acceleration motion backward. During this process, Af1+Af4<Ah1+Ah2. Even if the convex ring 32 is separated from the offside cavity 211, the pressure of the rear pressure cavity 222 is reduced to the pressure of the working cavity 212. The self-check valve 4 can also be stable at the front end of the self-check cavity 22 during the return acceleration stage of the piston 3.

[0048] During the backward movement of the piston 3, the convex ring 32 will leave the self-checking valve 4, so that the third reversing push valve oil channel 42 is connected with the working chamber 212, and the high-pressure oil enters the front pressurized three chambers 225 through the third reversing push valve oil channel 42, and then pushes the reversing valve 5 to change direction from the front pressurized three chambers 225 through the first reversing push valve oil channel 15, so that the reversing valve 5 is in the left oil port connection. Compared with the normal working state, the position of the self-checking valve 4 is at the front end of the self-checking chamber 22, and the third reversing push valve oil channel 42 enters the high-pressure oil earlier, which makes the reversing action of the reversing valve 5 earlier, and the stroke of the piston 3 is shortened, so that the impact energy of the piston 3 is reduced when it hits next time, and the impact frequency is higher. At the same time, the high-pressure oil enters the three pressurized chambers 225 on the front side, making Af1+Af4+Af3>Ah1+Ah2 on the self-check valve 4, and the self-check valve 4 moves toward the end of the self-check chamber 22 until the very end. During the movement of the self-check valve 4, the first step 43 will separate from the inner chamber 227. After the reversing valve 5 is reversed, the high-pressure oil no longer enters the three pressurized chambers 225 on the front side, but Af1+Af2+Af4>Ah1+Ah2 on the self-check valve 4, and the self-check valve 4 can still remain at the end of the self-check chamber 22 without moving.

[0049] Embodiment 2:

[0050] A rock drill provided in this embodiment includes the self-inspection structure for a rock drill described in Embodiment 1.

[0051] The above description is only a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A self-checking structure for a rock drill, characterized in that: include: A box (1) having a cavity (2); A piston (3) for impacting the shank end; A self-checking valve (4) for checking the operating status; The cavity (2) comprises a main cavity (21) and a self-checking cavity (22); the piston (3) is slidably arranged in the main cavity (21); the self-checking valve (4) is slidably arranged in the self-checking cavity (22); the main cavity (21) comprises an off-set cavity (211) and a working cavity (212); the diameter of the off-set cavity (211) is smaller than the diameter of the working cavity (212); the two sides of the self-checking cavity (22) respectively form two front pressure-bearing cavities (221) and two rear pressure-bearing cavities (222) with the self-checking valve (4); the box (1) is provided with an oil inlet normal pressure oil circuit (11) and an off-set signal oil circuit (212); The invention relates to a hydraulic oil circuit (12), an oil inlet normal pressure oil circuit (11) is connected to the two front pressure chambers (221), and two ends of the offside signal oil circuit (12) are respectively connected to the offside chamber (211) and the two rear pressure chambers (222); the piston (3) comprises a rod body (31) and a convex ring (32) protruding from the rod body (31), and the convex ring (32) cooperates with the offside chamber (211); when the self-checking valve (4) is in contact with the end of the self-checking chamber (22), the rock drill operates normally; when the self-checking valve (4) is in contact with the front end of the self-checking chamber (22), the rock drill operates abnormally.

2. A self-checking structure for a rock drill according to claim 1, characterized in that: The two sides of the self-checking cavity (22) and the self-checking valve (4) respectively form a front pressure cavity (223) and a rear pressure cavity (224); the self-checking valve (4) is provided with a balancing oil passage (41), and the balancing oil passage (41) communicates with the front pressure cavity (223) and the rear pressure cavity (224).

3. The self-checking structure for a rock drill according to claim 1 is characterized in that: It also includes a reversing valve (5), which is used to change the oil circuit to make the piston (3) reversing movement, and the self-checking valve (4) can control the reversing time of the reversing valve (5).

4. A self-checking structure for a rock drill according to claim 3, characterized in that: It also includes an oil inlet (6) and an oil return port (7); the main cavity (21) also includes a rear cavity (213); a front cavity oil circuit (13) and a rear cavity oil circuit (14) are provided on the casing (1); the front cavity oil circuit (13) is connected to the working cavity (212), and the rear cavity oil circuit (14) is connected to the rear cavity (213); the A port of the reversing valve (5) is connected to the front cavity oil circuit (13), the B port of the reversing valve (5) is connected to the rear cavity oil circuit (14), the P port of the reversing valve (5) is connected to the oil inlet (6), and the T port of the reversing valve (5) is connected to the oil return port (7).

5. A self-checking structure for a rock drill according to claim 4, characterized in that: The two sides of the self-checking cavity (22) are respectively connected with the self-checking valve (4) to form three pressure chambers (225) on the front side and three pressure chambers (226) on the rear side; the box body (1) is provided with a first reversing push valve oil circuit (15) and a second reversing push valve oil circuit (16); the first reversing push valve oil circuit (15) is respectively connected with the three pressure chambers (225) on the front side and the left oil port of the reversing valve (5); the second reversing push valve oil circuit (16) is respectively connected with the rear cavity (213) and the right oil port of the reversing valve (5); the self-checking valve (4) is provided with a third reversing push valve oil passage (42); the two ends of the third reversing push valve oil passage (42) are respectively connected with the three pressure chambers (225) on the front side and the main cavity (21).

6. A self-checking structure for a rock drill according to claim 5, characterized in that: It also includes an oil leakage port (8), and a first oil leakage passage (17) and a second oil leakage passage (18) are provided on the box body (1); the two ends of the first oil leakage passage (17) are respectively connected to the oil leakage port (8) and the rear pressure three chambers (226); the two ends of the second oil leakage passage (18) are respectively connected to the oil leakage port (8) and the rear chamber (213).

7. The self-checking structure for a rock drill according to claim 1 is characterized by: The self-checking valve (4) is provided with a first step (43), and the front pressure chamber (221) is provided with an inner cavity (227) that cooperates with the first step (43); one end of the oil inlet normal pressure oil circuit (11) is arranged on the inner cavity (227); when the first step (43) enters the inner cavity (227), a gap (228) is provided between the first step (43) and the cavity wall of the inner cavity (227) close to the front pressure chamber (221).

8. The self-checking structure for a rock drill according to claim 1 is characterized by: The self-checking valve (4) is annular and is arranged coaxially with the piston (3).

9. A rock drill, characterized in that: It comprises a self-inspection structure for a rock drill as claimed in any one of claims 1-8.

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