The analysis of the causes of coal winning machine walking wheel tooth fracture

The analysis of the causes of coal winning machine walking wheel tooth fracture - 2020 07 - 19 BaoZhiQiang ( China coal DaTun company, jiangsu peixian county 221611) Drum shearer traction way by a chain to develop without chain traction is a great progress in the history of the development of coal winning machine, now almost all coal winning machine adopts no chain drawing method. This drawing method can basically meet the production requirements, but walking round abnormal tooth fracture seriously affected normal mining operations of coal cutting machine, wheel tooth fracture is the main form of our company mining closed traction damaged. In the follow-up study a lot of walking wheel tooth fracture, and combining with access to relevant data on the basis of the walking wheel is obtained possible reasons for abnormal fracture of gear tooth. 1. Fracture analysis of the causes due to coal mining machine working conditions, complicated working condition, so the quantitative research to walk round the cause of the abnormal fracture of gear tooth has certain suffering, so this article only from qualitative analysis, the stress of the ideal working condition and so on several aspects to make some qualitative research. 1. 1 gear transmission characteristics of the coal winning machine walking wheel and pin rail face scraper conveyor pin row between pin tooth meshing rotation due to its simple structure, convenient disassembly, very suitable for low speed, heavy load and poor lubrication condition to workplace. In theory the most belong to the conjugate meshing transmission, so the ratio is also constant. When two teeth meshing alternately in the process of transmission, the transmission ratio will have a mutation, especially in rows with two pin connection. Walking wheel and pin pin tooth row of single tooth meshing transmission process as follows: by walking somewhere and pin tooth meshing tooth top, then walk along the rotation of the wheel contact points to walk round the roots of a move to the lowest meshing position, the meshing point to walk again move until exiting meshing tooth top, and then the corresponding tooth begin to enter the next engagement. Walk round at constant speed, the meshing process, the change of the corresponding rotational than as follows, under the meshing center distance of a given and pitch by the top position when entering meshing transmission is large, and then leveled off with mesh, but when the next tooth into mesh transmission ratio and larger mutation, will happen, of course, this is just the ideal shape work condition the changing rule of the linear speed of shearer, see figure 1. Actual coal mining operation in coal winning machine walking wheel and gear meshing center distance of the pin is not constant, at the same time because of the scraper conveyor of the horizontal and vertical curve has the role of distribution line of floating, pin tooth pitch in pin rows with pin joint than standard pitch has larger changes, thus make impact to walk round the larger, this is one of the reasons for abnormal fracture walk round. 1. 2 stress analysis of coal winning machine is working, the ideal working state of walking wheel tooth stress situation as shown in figure 2, the ф said pressure Angle, assuming that the torque M unchanged, because this mode of transmission for the conjugate meshing, as the meshing point to change, H is the change, pressure Angle ф also change, so the method also change to force F, traction Ft also change, when have a larger impact load or other reasons caused by walking gear force exceeds the strength of the material, walking can cause tooth fracture. 1. 3 coal winning machine is usually guided sliding boots aspects according to the conveyor horizontal bending & le; ± 1 degree direction, vertical bending & le; 3 degrees to design of traveling mechanism and scraper conveyor in over a period of time after use, due to wear and tear that make central groove curvature overrun, coal winning machine from there by, must rely on guided sliding boots to le pin row, guided sliding boots would be larger lateral force at this time, will lead to serious or make its force in the guide groove muscle tear, and once guided sliding boots is damaged, continue to work, the possibility of walking wheel gear teeth appear rupture can be increased greatly. 1. Four factors in terms of materials and heat treatment, heat treatment, if walk round the material composition is not reasonable, inclusion overrun and tooth surface hardness of carburizing during heat treatment has failed to meet the requirements, also can reduce coal winning machine performance, walking round in walking wheel is easy to break. 2. Conclusion above from the gear - Transmission characteristics of pin rail, simple mechanical analysis, guided sliding boots and heat treatment influence factors analysis of the coal winning machine walking wheel tooth fracture of some factors, including gear - Pin rail of the stress transmission characteristics, basic is inherent, and other relative is preventable, on the basis of the above analysis tentatively puts forward some preventive measures. （ 1) Guide the design of sliding boots must ensure its intermittent horizontal and vertical direction, such ability is very good to walk round, should be regularly check in is to use the guide sliding boots wear, wear large to be replaced in a timely manner. （ 2) Walking wheel material selection, blank piece must reach the use requirement when the forging, heat treatment, surface hardness to achieve HRC58 - walking gear 62, walking wheel core hardness of HRC38 - 42. Source: 'science and technology to become rich wizard' 2015 no. 2