The hydraulic rock drill was developed by the French Montabert company in 1970 and installed on the hydraulic drilling rig to facilitate mine drilling. In the development in recent years, due to the unique technical performance and perforation efficiency of hydraulic rock drills, countries all over the world have increased the research and development of hydraulic rock drills. A series of hydraulic rock drills are used in the field of tunnel traffic to improve the technical level of highway engineering construction. With continuous technological innovation, hydraulic rock drilling rigs and rock drilling robots have come out, which has expanded the application space of hydraulic rock drills and brought some application problems. Under such an environmental background, it is of great practical significance to explore the application and development trend of hydraulic rock drills.
1 Application of hydraulic rock drill
1.1 The front cover is loose
The front end cover and the rotating shell of the hydraulic rock drill are mainly connected by threads. When in use, under the influence of high-pressure shock and vibration, the front end cover and the rotating shell will loosen and buckle, causing the two convex wires to be damaged. In fact, the looseness of the front end cover will cause a certain large gap between the front end cover and the rotating housing, and jumping occurs during use, and the rear rotating large gear will be directly damaged by axial impact. The water seal is set on the front end cover. Due to violent beating, the sealing performance of the water seal will be destroyed. The flushing water will easily enter the rotating motor and enter the hydraulic oil tank through the motor oil return pipe, which will eventually cause the hydraulic oil to deteriorate, which is not conducive to the operation of the entire system. . In addition, water has a certain corrosive effect, which will rust the pumps and valves in the system and cause system failure.
1.2 Piston strain
In the process of road construction, new requirements are put forward for the technology of rock drilling rigs. The technical level of rock drilling machines will affect the construction efficiency of the entire road project, and the impact piston is a key component of the hydraulic rock drilling machine. In the long-term operation, the scrapping of parts due to piston strain frequently occurs during construction, especially for imported impact pistons, which are expensive, and scrapping and replacing will bring large production costs. Taking this into consideration, the person in charge decided to replace the cheaper domestic piston for the experiment. The piston did not impact, but found that the rock drill could not complete the return movement during the impact of the piston, which affected the system operation.
1.3 Difficulty in rotating pressure test
Through the test, the pressure of the rotary motor of the hydraulic rock drill is 150Bar. The test bench does not have any loading device, so the rotary pressure of the hydraulic rock drill cannot be accurately tested, and it is impossible to judge whether the rotary motor is normal. The hydraulic rock drill can only be set on the trolley to judge Rotary pressure, often due to insufficient rotary pressure to rework many times, wastes manpower and material resources. At the same time, the rock drilling jumbo contains a large number of hydraulic system components, the operation process is complicated, and the hydraulic components are prone to failure, which reduces the rotational pressure of the rock drill, is not conducive to interference judgment, takes a long time to troubleshoot, and has a large workload.
2 Application and modification of hydraulic rock drill
2.1 Optimize the installation method and solve the problem of loose front cover
For the loosening of the front end cover, construction personnel generally choose the following methods: one is to reversely install the skeleton oil seal, the other is to install a fastening agent on the front thread, and the third is to connect the front end cover and the rotating housing together, but these methods cannot fundamentally to solve the problem. After the rock drill was disassembled, the construction personnel measured the dimensions of each component, and found that there was a gap of about 13.5 mm between the front end cover and the water seal position. Among them, the wall thickness of the front end cover was 20 mm, and positioning bolts could be set here to achieve Tightening and relaxing effect. After tightening the front end cover and the rotating housing, drill a Φ6.8mm, 2.5mm deep internal control, ream the hole to make the depth 10mm, tap and install the hexagonal bolt, so that the hexagonal bolt and the threaded connection position are tightly connected, so as to To achieve the effect of loosening.
2.2 Improve the surface of the piston to solve the problem of piston punching and straining
The problem of piston strain is mainly caused by the loss of balance of the piston balance groove and the lubrication effect of oil storage. On the basis of ensuring the strength of the material, the original balance groove is deepened and widened by mechanical processing, which meets the processing accuracy requirements. Process and transform all the balance grooves on the surface of the piston, install the modified impact piston on the hydraulic rock drill, and repeatedly test, it is found that the impact and direction of the piston are relatively sensitive, which can be applied to road construction to ensure the normal operation of rock drilling operations. Various technical requirements and production standards. After five months of use, the construction personnel dismantled and inspected the piston of the hydraulic rock drill, and did not find any signs of wear and strain, which once again proved the effectiveness of the transformation. Considering the high price of imported equipment, in order to control the cost of equipment consumption, on the basis of ensuring the normal operation of the rock drill, the domestic impact piston was selected to replace the original imported impact piston. Since the technical standard has not yet been reached, in the comparison experiment, the imported impact piston was measured. The position of the piston, the main reason why the domestic piston cannot meet the requirements is that the size of the force-bearing surface used to reduce the impact inertia is about 2mm larger than that of the imported piston. In actual movement, increasing the outer diameter of the piston will cause the return oil circuit to be closed. In the optimized transformation, the outer diameter of the piston is ground, the circuit clearance is increased, and the pressure difference between the steps is formed, thereby promoting the completion of the piston return action.
2.3 Optimize the pressure test and solve the problem that cannot be tested
The transmission shaft is installed on the hydraulic test bench, which is respectively connected to the rotary motor of the rock drill and the bracket. A safety valve with a limit value of 170 Bar is installed on the oil supply circuit of the rotary motor to avoid the problem of system overload. In the experiment, the loading valve is used to pressurize the rotary motor of the rock drill until the maximum limit. If the pressure remains stable, it means that the rotary motor of the rock drill is in normal working condition, otherwise it means that there is a fault, and the processing continues. It can be seen from this that using the pressure test to help construction personnel accurately judge the operating status of the rock drill rotary motor can not only realize the quality inspection of the rock drill after repair, ensure the performance of the rock drill, save a lot of unnecessary repairs, but also judge the rock drill through the test method. Troubleshooting causes, saving troubleshooting time, and effectively improving the maintenance efficiency of hydraulic rock drills.
3. Development trend of hydraulic rock drill
After the continuous innovation and improvement of the structure of the hydraulic rock drill, the technical performance has become more and more perfect, and the parts have been greatly improved and improved in terms of parts accuracy, reliability and wear resistance, and a heavy-duty hydraulic rock drill has been developed. The operation makes the hydraulic rock drilling equipment develop in the direction of large-aperture drilling, which further improves the drilling efficiency and reduces the operating cost. The application of large-aperture hydraulic drilling rigs is conducive to the drilling of inclined holes, which greatly enhances the blasting effect, improves the quality of ore grinding and crushing, and is conducive to later shipment.
3.2 Evolution of high-speed drilling
In the development and application of high-power heavy-duty hydraulic rock drills, the structural parameters of hydraulic rock drills have become more reasonable and scientific, especially the structural strength, stiffness, and reliability of parts have been rationally designed, and performance parameters can be automatically adjusted according to rock conditions. , to realize the improvement of the operating efficiency and drilling speed of the hydraulic rock drill.
3.3 High precision
Hydraulic rock drills are mainly based on ordinary drilling tools, which have a high drilling speed and low wear. In actual use, the blast hole will be deflected, which will reduce the drilling accuracy. In recent years, some foreign manufacturers have increased their research on drilling tools for hydraulic rock drills and achieved remarkable results. In 2009, Sandvik Company developed a composite drilling tool set, which effectively separates the large pipe rotation and the drilling head, and transmits the impact force formed during the operation of the hydraulic rock drill to the rock, including the outer casing and the internal drilling rod. The position is connected by the recoil buffer to keep the alignment accurate, and the drill rod is installed at the concentricity of the casing so that the drill rod can only transmit the impact force and provide propulsion for the operation of the hydraulic rock drill. The function of the casing and the drill pipe is the same, mainly to transmit the rotary motion to the drill bit, as the direct guide rail of the drill set, strengthen the drill set system, and then improve the accuracy of the blast hole.
The diesel engine contains an electronically controlled fuel injection system. In actual operation, the fuel injection volume can be adjusted according to the usage requirements to promote the mixing of oil and gas to achieve full combustion, reduce NOX, PM and other harmful gas emissions, and avoid damage to the environment. severe pollution. Build an ergonomic cab, anti-rolling, noise, falling stones, and has the advantages of panoramic vision and air purification. At the same time, the hydraulic rock drill will not discharge oil mist and noise during actual use, realizing the safety, comfort and environmental protection of equipment operation. At present, the noise of hydraulic rock drills exceeds 90dB, and its sound source is in the frequency range of 1-5kHAz, which is within the sensitive frequency of human ears. Relevant manufacturers are also stepping up research on environmental protection of hydraulic rock drills. Through comprehensive measures, the operation of the drilling rig is controlled by long-distance wired or wireless, so that the operator is out of the noise environment and ensures the health of the ears.
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