Solve the problem of breaking the lower core bolt (Fengtai Depot of Beijing Railway Bureau, Beijing 100070). In the past one year, the Fengtai vehicle section has found that the failure of the lower core bolt is more and more broken. According to the statistics of January-May 2001, about 2% (%~30% of the repairs to the station (see Table 1) are seen from the model, and the box car takes up 6% of the repairs. The number of breaks, from three to four, and five or six for inspection, break one or two, generally do not deal with; break three or four, some with new bolts, some with brake shoes Wear; if there are more breaks, the car will be handled. Table 1 Fengtai vehicle segment core plate bolt breakage failure statistics table 2 lower core plate bolt breakage condition must have nut root thread and bolt middle 3 parts (see) 3 reasons analysis month total temporary repair break percentage percentage of different models Open car box car flat car total 1 core plate bolt breakage hazard After the core plate bolt is broken, it will cause the displacement of the heart plate and the heart plate pad on the bolster (see), so that the center of gravity of the cargo is offset, and the core plate bolt is loose at the high speed through curve 1 After the core plate bolt is broken, the lower part of the core plate bolt is loose, and under the impact of the vehicle, the bolt is not loose or loose. The bolt will be subjected to a large shear force depending on the degree of looseness of the other bolts. When the force reaches up to 8 bolts and the bolt is broken at the same time, the core disc, the disc plate and the bolster have begun to be displaced relative to each other, so that the remaining bolts that have not been loosened (or relatively loose) are left. Breaking one by one. In addition, after the lower core bolt is loosened, the wear of the bolt is intensified during the running of the vehicle. In the inspection, the worn portion of the M22 bolt has reached 18 mm, which causes the bolt strength to be reduced and broken. 2The core plate bolt has no service life and the wear limit. As long as the threaded part of the bolt can be used, it can be used indefinitely. No matter the degree of wear, the material fatigue and wear of the bolt will increase the bolt strength and break. 3The core plate bolt nut has no fastening force. The standard core plate bolt nut is generally tightened with a pneumatic wrench. When the wind pressure is unstable, the tightening force of the 8 bolts and nuts will be insufficient or uneven. When it is easy to cause the core plate bolt to break. The misalignment of the heart plate is carried out on one side of the wheel, and the other side of the wheel is deloaded and derailed. In addition, a large number of core plate bolts are broken and the buckle is repaired. First, the workload of the large station repair is increased, and the maintenance cost is added. Second, the normal arrival of the goods is affected. Third, it affects the railway production and vehicle turnover. 3.4 Heavy-duty speed increase causes the force of the vehicle parts to change. The tonnage of the cargo trains is constantly increasing. At present, it has reached 45,000 tons, and the Daqin line has also opened tons of trains. Meanwhile, Freight trains are also gradually increasing speed. At present, the speed of 80km/h~90km/h has been increased, and the force of the vehicle parts has changed. The failure rate of some accessories has increased significantly, including the breakage of the core plate bolts. Investigation and Suggestions on the Purification of Wind Sources Li Zheng and Li Zhexin 2 (1. Vehicle Department of Hohhot Railway Bureau, Hohhot, Inner Mongolia 010057; 2. Hohhot Railway Bureau Passenger Transport Company, Hohhot, Inner Mongolia 010057) 1 Investigation of current situation, railway locomotive braking The compressed air used in the machine is a mixture of gas such as oxygen and nitrogen, dust and water vapor, etc. The worn powder and lubricating oil vapor have mechanical impurities such as welding slag and rust when flowing through the system, resulting in both liquid water and oil in the brake pressure air, as well as gaseous water vapor and oil vapor and solid micro-granular machinery. Impurity brakes contain dust and condensed ice in the compressed air, which not only adds the maintenance work of the valves of the brakes, but also adds unsafe factors to the railway transportation, especially in the cold regions, the condensed water can make the brakes malfunction. In the event of a traffic accident or even a major accident, such as the 335 passenger trains attached to the Tumen depot on January 27, 1980, when the oar line was running, the third brake pipe of the vehicle was frozen. 4-The 9th passenger car brake failed, causing a major accident in which the locomotive and 3 passenger cars derailed. On September 6, 1996, the 201 passenger trains assigned to the original Hohhot depot were the 7th CA91129 after the machine was discovered at Baotou Station. The 104-distribution valve action part shrinkage hole is blocked by foreign matter, causing mitigation, the train is delayed due to the treatment failure. On December 5, 1999, the 89 passenger trains of the original Huhe section were found at the south exit station and the first XL4992 was found. The water in the emergency valve of the 104 distribution valve is frozen, and the emergency valve is exhausted, and the train is delayed due to the failure of the treatment. According to the data survey, 26% of the vehicles in the whole road will have a direct failure or indirect impact caused by the brake air being unclean. In the statistics of braking accidents occurred in winter transportation in alpine regions, about 40% of accidents are related to brake compressed air condensate. According to statistics, the GL valve and 104 valve failure caused by the brake air is not cleaned in the original call and the segment accounted for 60.5% and 56% of the total number of faults respectively. It can be seen that the problem of cleaning the wind supply and source of the brake is solved. It is imperative to ensure the safety of driving. 2 The problem of poor cleaning of the wind supply and air supply is analyzed. The impurities in the wind source are generally three kinds of water, oil and dust impurities. When the pressure is not large, the absolute pressure of the compressed air is basically proportional to the absolute moisture content. Therefore, the water content of the compressed air itself is several times the water content of the atmospheric air. When the air temperature of the air compressor does not exceed 160*C After the two-stage water cooling of the air compressor and the natural cooling of the air supply pipeline, the condensed water is further precipitated in the pipeline, which is the inevitable result of the operation of the air compressor and the pipeline system. The oil is generated when the air compressor is working. The lubricating oil is mixed with the compressed air and the dust is generated because the air suction port of the air compressor sucks in the polluted air, and the installation position of the air filter is too high. The cleaning and replacement of the filter element is not timely, so that the dust filter is highly polluted and the dust is easily polluted. In addition, the rust inside the pipeline causes the surface rust dust to enter the wind source. Although the air compressor itself is equipped with two oil-water separators, the operator is required to discharge -2 times a day, and the discharge valve of the lower body of the storage cylinder is required. Regular discharge on a daily basis. Since these are all manual operations, the operator does not know enough about the importance of the quality of the wind source, and if it is not implemented according to the relevant standards, the ground wind source is not clean. These gases contain a water-soluble binder that will remain as the gas passes through the brake pipe system, the three-way valve, the fiber pores of the distribution valve, the matte surface, and the location where the geometry suddenly changes, increasing the friction surface resistance. Even dry grinding occurs, and there is a gap in the sealing part. It is recommended that the scientific research department recalculate the strength of the design core plate bolt for the actual situation of speed-increasing and heavy-duty trains. It is recommended to formulate the core plate bolt wear limit. The tightening force standard, the maintenance personnel use the standard torque wrench to tighten the bolts and nuts to prevent the lower core bolts from loosening. The Ministry of Railways has ordered the use of FS type or ST2 type locknuts since March 2000, which fundamentally solves the lower core disc. It is recommended that all units be strictly controlled from the feeding, installation and completion of the vehicle to ensure that the bolts are broken. Horizontal Deep Hole Drilling Machine Horizontal Deep Hole Drilling Machine,Deep Hole Drill,Cnc Deep Hole Drilling Machine,Deep Hole Drilling Machine Shandong EN FIN CNC Machinery Co., Ltd , https://www.shuofangcn.com
Solve the problem of breaking the lower core bolt
Solve the problem of breaking the lower core bolt (Fengtai Depot of Beijing Railway Bureau, Beijing 100070). In the past one year, the Fengtai vehicle section has found that the failure of the lower core bolt is more and more broken. From the statistics of January-May 2001, about 2% to 30% of the repairs (see Table 1)