| Bulldozer bulldozer transmission gearbox is a core component of our country since the 1979 introduction of technology from abroad, after 30 years of development has been fully achieved domestically, but the transmission quality of domestic and foreign stability still some gaps, especially early the fault persists. After dismantling, early gearbox failure often made mostly by sealing rings caused by abnormal wear, the quality of domestic stability of the sealing ring reach the international advanced standards. This article appeared dismantling the early failure of the gearbox, abnormal wear of the seal ring analyze the chemical composition and physical properties, to identify abnormal wear reason sealing ring, by improving the surface quality of the sealing ring fitting and sealing ring designed to solve the sealing ring tension abnormal wear problem.Study the working principle of the seal ring, and analyzes the forces of the sealing ring, the sealing ring by the radial force of hydraulic oil to the gearbox at work, when rotating axial force and their own tension, and the lockup clutch seal ring groove, bearing end surface friction. Surface quality and fitting of the sealing ring, the sealing ring itself is caused by the tension of the size of the abnormal wear of the key factors. Seal ring, bearing end face because the structure is simple and easy processing, can reach the surface roughness values of Ra0.4 drawings, the lockup clutch seal ring groove because of processing difficulties concave is deep and narrow, it is difficult to reach the surface roughness of Ra0.4, it is one of the important reasons for the sealing ring abnormal wear. Sealing ring opening gap is large and unstable, floating between 17mm-21mm, the corresponding self-tension is too large, easily lead to locking, it is another important cause abnormal wear of the seal ring.Research on the seal ring groove surface quality grinding process, the traditional seal ring groove surface quality is fine by car to complete, can only reach the surface roughness Ra1.6 and unable to improve sheet quality Ra0.4, reach drawings requirements, and the traditional processing technology for the installation and the amount of feed of the tool is demanding, prone to waste. Grinding is an effective means to improve the surface quality, based on cost and performance requirements, select a ductile material as a polishing tool, select the W14 alumina as an abrasive, equipped with grinding paste and thinner, use 50-70r/min speed lathe processing, and finally got the seal ring groove surface quality Ra0.4 of.When closing the opening gap and work to study the impact of the free state seal ring seal ring wear tension and improves the tension measurement method, obtained tension free state with the opening of the seal ring there is a linear relationship between the gap, the formula is:Tension ≈1.75* opening gap. Modify the seal ring drawing technical requirements, opening a gap of approximately 14-15mm in the free state, the closed state of tension about 24.5-26.5N. Re-tooling produced heat setting, the original setting is heat sealed around the tooling outside the fixed opening size of the insert, in the heat treatment process prone to external expansion deformation. The new heat setting is set in the tooling inside the sealing ring, fixed by the Cypriot block size of the opening, during the heat treatment does not occur outside the expansion deformation, to ensure that the opening gap of around 14-15mm, thereby controlling the seal tension size. |
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