Key hints: the repair method of Komatsu D375A-3 bulldozer's crawler assembly: the two Komatsu D375A-3 bulldozers purchased and put into use at the beginning of 1996, mainly undertake the heap of all blasting stones in the key project of the Xi'an City, the slope of the dam shoulder of the dam and the opening and control of the foundation pit, and the smoothness of the sand gravel in the dam shell.
The two Komatsu D375A-3 bulldozers, purchased and put into use at the beginning of 1996, mainly undertake the heap of all blasting stones in the key project of the Xi'an City, the Heihe hub project, and in the opening and control of the foundation pit, as well as the smoothness of the sand gravel in the dam shell. The track wear of the bulldozer is faster. After 4500h, the crawler rack and rack (abbreviated, the same) and the caterpillar pin (hereinafter referred to as the pin set, the same below) have reached the maintenance limit (see Table 1 and the chart). It must be repaired, otherwise the work efficiency and economic benefit will be significantly reduced, and the whole assembly will be caused after serious wear and tear. Because of no repair value and scrapping, according to the wear condition of the track, chain links can continue to be used, but the pin and shoe must be repaired.
Code name
Repair of 1 pin
The right to use will continue to be used after turning the pin sleeve 180o. Therefore, the model's crawler is lubricated. During the repair process, the wear condition of the inner diameter of the pin and the outer diameter of the pin shaft can be carried out separately: (1) the wear is small, the sealing performance is guaranteed, and it is still used as the lubricating type assembly. (2) large wear and lower sealing performance may be considered to be filled with grease filling type (that is, on the surface of the pin shaft and on the surface of the pin sleeve, the lithium base grease yamen is assembled). When assembling the worn pin, attention should be paid to the wear direction of the pin to the mounting surface of the track plate. Because the maximum thrust of the chain is 1700kN, we have to be able to provide the necessary seals and entrust "the Beijing integrated service maintenance department" to complete the repair work.
Repair of 2 crawler teeth
The method of using welded steel. As far as possible, the original standard size and performance of carbon should be restored. The key point is to solve the problem of material selection and welding process.
2.1 material selection
Through comparison of various schemes, it is considered that the rail top part of 50# waste rail with material "U71Mn" is suitable as the material for gear welding.
(1) the main chemical composition and mechanical properties of this type of rail are close to those of the track plate.
(2) the size of the rail top is close to the size of the worn part of the track.
(3) good economy: purchase of waste rail, low cost of material; cut and down material under the need of gas cutting, simple process, low processing cost, low loss, high material utilization, two cutting of the remaining rail waist and rail bottom, is the quality material of other parts of welding repair machinery.
2.2 welding
The weld is located at the lower part of the shoe, and the work is mainly subjected to the asymmetric alternating tension of the deformation of the teeth. Therefore, the tensile strength of the weld is the main contradiction. No cracks or severe deformation will occur during welding. From the point of view of reducing the cost, we use the 4mm J506 structural steel electrode to conduct full face welding. However, the tensile strength of the weld is low, and it can not be used normally. Because the tiger added a birth reinforcement in the middle of the crawler, it can improve its bending strength, improve the stress condition of the weld, and make up for the low tensile strength of the weld.
