Basic performance of the hottest hydraulic rock dr

Basic performance of hydraulic rock drill

the basic performance of hydraulic rock drill can be divided into impact performance, rotation performance, rock drilling performance and noise characteristics. Therefore, it is inappropriate to ignore one aspect when analyzing hydraulic rock drill. Of course, different rock conditions have different requirements for hydraulic rock drills. For example, the torque of hydraulic rock drills used in coal mines should be higher, and the impact energy is a kind of auxiliary motor. The value of indirect speed change device can be lower than that of some iron mines, but the index value of basic performance must be guaranteed

1 hydraulic rock drill impact performance parameters

hydraulic rock drill impact performance parameters include impact energy, impact frequency, impact power and working condition parameters: working pressure, working flow. The impact power of hydraulic rock drill indicates the impact capacity of its impact mechanism, which is determined by the following formula:

p=e.f (1)

where p - impact power, kw

e - impact energy, j

f - impact frequency, hz

the working pressure of hydraulic rock drill impact mechanism is the decisive factor affecting impact energy and impact frequency. The test confirms that the establishment of the impact working pressure of the hydraulic rock drill should be guaranteed by a certain working flow. When the flow is not enough to establish a certain working pressure, increasing the flow can increase the working pressure, so as to improve the impact energy and impact frequency; When the flow can meet the impact mechanism to establish a certain working pressure, increasing the flow will not improve the impact performance. After the product structure is determined, the stroke of the impact piston is certain, and the higher the speed of the impact piston is, the higher the impact frequency is. Therefore, the impact frequency can directly reflect the impact energy of the hydraulic rock drill. Whether the impact performance of the product meets the requirements can be judged by the corresponding relationship between the working pressure - impact frequency and also the attention rate - working flow of the impact mechanism of the hydraulic rock drill

2 rotary performance parameters of hydraulic rock drill

the rotary performance of hydraulic rock drill is an important performance. Compared with traditional pneumatic rock drill, the torque of rotary mechanism of hydraulic rock drill is greatly increased, which exceeds the increase of impact energy. Suitable for drilling hole diameter φ In the hydraulic rock drill of 30 ~ 60mm, the impact energy is mostly 100 ~ 250j, which is not much higher than that of the pneumatic independent rotary rock drill, but the torque is 200 ~ 300N m. More than doubled

through experimental research, the drilling efficiency of hydraulic rock drill is higher than that of pneumatic rock drill. In addition to the increase of impact power, the increase of torque of rotary mechanism plays a significant role. Researchers from Beijing University of science and technology put forward the viewpoint that hydraulic rock drilling "Impact Torsional Shear heald is a typical rock breaking effect of reinforced composite materials"; We also found in a large number of rock drilling experiments that the drilling speed can often be increased by 20% - 30% by adjusting the rotary performance parameters of the hydraulic rock drill when the impact performance parameters remain unchanged. According to the test, drill and chisel φ When the rock hole is less than 55mm, the average torque is 100 ~ 150n m. But the peak value often reaches 150 ~ 250n m. It becomes the rotary "overload" resistance in the process of rock drilling, which is caused by the regular changes of rock properties, rock fractures and the instability of drilling propulsion system. If the servo propulsion system with good performance is adopted, and the propulsion force is adjusted in time to reduce the rotary resistance of the hydraulic rock drill in time, the torque of the rotary mechanism can be slightly lower

in the rotary performance of hydraulic rock drill, the rotating speed is another important parameter, which affects the rock breaking amount of impact crushing each time, and also affects the rock breaking amount of "rotary torsional cutting", so as to change the cutting speed

the rotary mechanism of hydraulic rock drill is almost independent of the impact mechanism. The influence of its performance parameters on the drilling speed is mainly because it can change the propulsion force. The test rules we summarized are:

(1) when the impact performance parameters and rotation speed are fixed, the propulsive force increases and the rotation torque increases. Within a certain range, the drilling speed increases, but after the optimal propulsive force rises to a certain peak, the propulsive force increases again, which will reduce the drilling speed. The rotary torque value of the hydraulic rock drill, that is, the maximum torque value that can be achieved, plays a role in ensuring the best propulsive force in the rock drilling process

(2) when the impact performance parameters and drilling propulsive force of the hydraulic rock drill remain unchanged, the hydraulic rock drill has the best drilling speed at the best speed, and the torque increases with the increase of the speed

(3) when the rotary drilling speed and drilling propulsive force of hydraulic rock drill remain unchanged, the actual output torque is not affected by impact energy

improve the understanding of the importance of the rotary performance of hydraulic rock drill, and take the rotary performance as an important index to assess and evaluate in the development, manufacture and use of hydraulic rock drill products

3 noise characteristics of hydraulic rock drill

compared with pneumatic rock drill, hydraulic rock drill has no exhaust noise. Although the sound pressure level of the noise generated by the rock drill during the tensile performance inspection is much lower than that of the pneumatic rock drill (the sound pressure level of the pneumatic rock drill at a distance of 1m is more than 110dB (a)), it is still higher than 90dB (a), up to about 100dB (a), and the sound energy is mainly concentrated in the frequency range of 1 ~ 5KHz, which does not exceed the sensitive frequency range of human ears. If noise protection measures are not taken, it is still harmful to workers

through experimental research, the noise sources of hydraulic rock drill mainly include the noise generated by impact mechanism, rotary mechanism and rock crushing by drill bit. The noise generated by the impact mechanism includes the injection noise generated by the impact piston and the enclosed space at the drill tail, the structural noise generated after the impact piston impacts the drill tool, and the pressure pulse noise generated around due to the deformation of the impact surface. Among them, the structural noise is the main component, and its noise frequency characteristics are consistent with the structural vibration frequency. The noise of slewing mechanism is composed of hydraulic and mechanical noise of slewing mechanism, but the noise intensity is lower than that of impact mechanism, and the sound pressure level difference is more than 10dB (a), so it has little impact on the overall noise evaluation of hydraulic rock drill. The noise produced by the drill bit breaking rock has a great impact on the noise test of hydraulic rock drill. When the drill bit is 0.5m deep into the rock, this impact can be ignored. Therefore, the research, testing and analysis of the noise of hydraulic rock drill mainly focus on the noise generated by the impact structure

the experimental study on the impact noise of hydraulic rock drill and the measurement and analysis of the vibration frequency characteristics of its impact mechanism show that the noise of hydraulic rock drill is mainly related to the impact energy, but is not affected by the impact frequency. Because under certain conditions, the impact energy of hydraulic rock drill depends on the working pressure, choosing the appropriate working pressure is the key to reduce the noise of hydraulic rock drill. The noise of hydraulic rock drill is mainly caused by structural noise. The structural clearance of hydraulic rock drill, accumulator parameters, the characteristics of impact materials and the tightness of connectors all affect the noise of hydraulic rock drill

the experimental research on the noise of hydraulic rock drill can be used to compare the performance of different products, seek countermeasures to prevent and control noise, and diagnose the fault of hydraulic rock drill. (end)