What are the main factors affecting the performance of roadheader?       

The performance of the roadheader is the key to the rapid excavation. Based on the existing results, the main factors affecting the performance of the roadheader are comprehensively analyzed.

First, from the design, processing and manufacturing of roadheader analysis

1, the stability of the whole machine operation. The operation stability of roadheader has great influence on its working efficiency and safety. In comparison with the horizontal roadheader, the longitudinal shaft boring machine achieves the same stability, and the weight needs to be increased by about 20%. In the TBM operation, may occur after rollover, and rotation along the vertical axis track slip instability. Increasing the body weight can improve the stability of roadheader operation, but on the one hand, it will increase the cost, on the other hand, it will make the roadheader prone to subsidence in wet and low-lying environment. According to statistics, in the work process, because the machine in the space position is not stable, resulting in downtime of 26%, due to motor breakdown caused by downtime accounted for 20%. The stability of roadheader directly affect the normal operation of other actuators, thus enhancing the stability of the tunneling machine, to improve the mechanical properties of the roadheader, enhance the work efficiency, is of great significance to reduce the fault.

Loading coordination mechanism action 2, star. The loading mechanism is one of the main working mechanism of roadheader, its role is the coal rock cutting mechanism under the dilapidated collection, harrow mounted to the middle conveyor. The size of loading capacity depends on the selection of loading mechanism parameters, which directly determines the production capacity of the whole machine. Therefore, improving and improving the loading mechanism of roadheader is the premise to improve the performance of roadheader.

3. The comprehensive factors of cutting head and pick. Pick is the key component of roadheader, its material and manufacturing process will have a greater impact on the performance of roadheader. With the extension of the application range of roadheader, the requirement of the hardness and fatigue strength of the pick increases. At present, most of the cutting materials of domestic roadheader are cemented carbide, such as 35CrMnSiA, and its disadvantage is brittleness. Because of the complexity of geological conditions of rock tunneling machine operation requirements, cutting teeth with high hardness, good impact resistance, abrasion resistance, stable work ability in order to protect the boring machine in cutting quartz rich rocks. Not only the material of the pick is very important, but also the shape of the pick and the arrangement of the cutting head, the influence on the performance of the roadheader can not be ignored. As the pick pick has a good self sharpening, impact resistance and has been widely used. The arrangement of the cutting head directly affects the stability and efficiency of the whole machine.

4, the power of roadheader. At present, the power of roadheader is generally small in our country, and the roadheader in developed countries is generally in 200kW - 300kW, the highest approaching 500kw. The power is too small, which is not conducive to cutting more hard rock and improving operation efficiency. Therefore, it is necessary to strengthen the development of large power roadheader. In order to give full play to the performance of roadheader, it is necessary to reserve a certain reserve power. From the current development trend of roadheader, high-power roadheader will become the main type of mine.

Two. Analysis from environmental factors

1. Dip angle of strata. For a roadheader, when there is no dip angle, the cutting speed is 8m3/h, and when the dip angle exists, the cutting speed is 10m3/h.

2. Tunnel inclination angle. The tunnel with a certain dip angle can make good use of the gravity of the medium carbon, and it is easy to load after cutting. At the same time, the coal can be prevented from circulating in the cutting head and working face, so as to enhance the working efficiency and reliability of the roadheader.

3. Strength of rock mass. The strength of rock mass has obvious influence on the working efficiency of roadheader. The strength of rock mass is larger, the energy needed for cutting unit volume rock will increase, and the working efficiency of roadheader will also decrease. It is reported in the literature that when the rock mass strength is 21MPa, the energy required for cutting unit volume rock is 11.2mj/m3, and the working rate of the roadheader is 25m3/h. When the rock strength is 45MPa, the energy required for cutting unit volume rock is 16.3mj/m3, and the working rate of the roadheader is 20m3/h.

4. Rock injection. Wet strata and dry strata have great influence on the working performance of roadheader. By comparing and analyzing, the rock with 11 liters of water injected per minute compared with the dry rock, the rock mass strength is equal to the same, the former roadheader efficiency is 50m3/h, the latter is 25m3/h. Thus, the rock water content has a greater impact on the efficiency of roadheader. But the mechanism research is still in the blank stage. In addition to the above factors, there are many geological environmental factors that affect the performance of roadheader, and the mechanism is quite complex, which needs further study.

Three. Conclusion

Based on the method of systematic analysis, the factors that affect the performance of roadheader are comprehensively analyzed, that is, the internal factors of roadheader and the external factors of working environment. The internal factors include: the stability of the operation and coordination of the star wheel loading mechanism of action, comprehensive factors picks, power driving machine control system, hydraulic system, water supply system, walking system; external factors include: rock angle, tunnel inclination, rock strength of rock water etc.. According to the comprehensive analysis of the influence of roadheader performance, it has certain guiding significance for the design and use of roadheader.