The magnitude of the pre-tightening force is mainly determined by personal experience, but when the pre-tightening force is too large, the bolt will be plastically deformed and loosened or even broken when accidentally overloaded. When the pre-tightening force is not enough, after a certain period of use, it will cause natural loosening. Due to human factors, the pre-tightening force of the eight bolts is inconsistent, resulting in inconsistent load on each bolt and eccentric load. In severe cases, bolts with large loads may be broken.
In view of the above reasons, in order to better solve the problem of loosening of the lower core bolt, the following anti-loose measures are proposed: (1) changing the quality of the mat, using hard mat.
Instead of wooden slabs, the slabs with small deformation and small impact resistance, compression resistance, anti-aging and good performance are used. At present, railway track vehicles mainly use bamboo core plate, which has large compressive strength and small deformation, which can effectively prevent the bolt loosening caused by the shrinkage of the pad.
(2) Changing the structure of the pad The pad is changed from wood to cast steel and the flat structure is changed. When the cast steel backing plate is cast, the main edges of 80 mm in length, 20 mm in height and 30 mm in height are respectively cast on two sides perpendicular to the direction in which the vehicle is pulled, as shown. In this way, after the lower core plate, the backing plate and the bolster are assembled, the main edge of the lower part of the backing plate and the bolster are two, and the upper main edge is closely adhered to both sides of the heart plate. The traction impact load can be transmitted by the friction of the main edge and the joint surface. Thereby, the core plate, the pad and the bolster can be formed into a relative whole body, the bolt is reduced by the impact load or the pre-tightening force is insufficient, and the heart plate is slipped relative to the longitudinal direction of the bolster. As shown, the core plate bolt can be prevented from becoming changed. Curved, broken or gradually loose.
Track flat car bogie cast steel pad structure 11 core plate; 21 pad; 31 bolster; 41 upper pad; 51 lower pad core plate, pad, adjustment plate, bolster assembly (3) with effective defense The loose measures are for the double nut anti-loose or the spring washer to prevent loosening. In the case of large impact, the anti-loose device of the washer is not effective. The fact that the effect is not good can be used to prevent the bolt from loosening on the two bolts at each corner of the disc. ,Such as. This method is economical and reliable, and is suitable for the high-speed operation of the track flat car.
By using the hard pad with impact resistance, high strength and small deformation on the lower core pad, the pad structure is optimized, and the method of stopping the washer can effectively prevent the looseness of the lower core bolt, to the vehicle manufacturer or The use of the unit is a more economical and ideal improvement method, which is conducive to improving the safe running speed of the vehicle. The anti-loose measures were adopted by the Zhengzhou Bureau of the Ministry of Railways, Xiangfan Machinery Factory (the designated manufacturer of the electrification construction equipment of the Ministry of Railways), which was appraised by relevant professionals and found to have good results in practical applications.
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