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DFH T90 industrial bulldozer is a new product developed by our company in 1998 , because of its small tonnage , thrust, especially suitable for Class I earthmoving operations of small and medium projects ~ Ⅲ soil , so the majority of users.

      But early in the market, users are reflected in use for some time appeared guide wheel is damaged, badly worn boot shaft , bushings burning phenomenon. To this end, I have launched a quality research and find a solution.

      A , T90 structural principle guiding Idler wheel for supporting and guiding the crawler crawler winding its crawler track links the outer rim stuck , preventing lateral off, and by cushioning device connected thereto tensioning tensioning caterpillar , transmitted to the chassis from the ground to ease the impact force . Its structure diagram in Figure l . Idler steel plate welded structure, which was a box-shaped radial cross-section . Guide wheel rim by a double metal jacket bore of the guide slide mounted on the axle bearings , the shaft is fixed to the ends of the left and right bracket. Guide wheel and the use of floating seal around the stent and the stent through the left guide wheel locking pins pressed between the floating seal and O -ring. In the guide wheel cavity add oil to ensure that the sliding bearing lubrication and cooling

      Two wear cause analysis demonstrated by inspection , guide wheel wear, the sliding bearing bush is burned since the guide shaft and the sliding lubrication between the bearing sleeve deterioration occurs, the partial conversion of the boundary lubrication state and a dry friction caused . In normal operation , the guide shaft and the sliding bearing between the hub and have a certain gap exists film forming liquid lubricant , whereby the heat generated is small, the lubricating oil taken by the bearing operating temperature is in the normal state. If the bearing sleeve and the shaft lubrication deteriorated state forms part of a dry friction , the friction power sharply increases , a large amount of frictional heat ; when the temperature exceeds the melting point of the surface of the sleeve , the sleeve begins to melt the surface until completely burning

      The main factors leading to poor lubrication guide axle are:
      ( 1 ) set of guide wheel bearings bimetal ∮ 0.025 concentricity tolerance . Crawler will produce vibration and shock jump , powerful impact and passing through the sliding bearing , thus requiring the slide with the gap between the bearing and the shaft even higher bearing concentricity requirements. If the geometric size tolerance , resulting in the boot shaft and sleeve gap is too small or no gap , the lubricant film thickness is not enough or no lubricant film .

      ( 2 ) guide shaft surface roughness Ra1.6 tolerance. If the guide wheel roughness tolerance , and many peaks metal ribs on the shaft surface , the metal edges destroy the integrity and continuity of peak oil film between the shaft and the sliding bearing. Work, oil will produce a lot of metal debris , the shaft and the bearing surface roughness increases , lubrication condition has deteriorated even further , causing severe sliding guide shaft and bearing wear .

      ( 3 ) the original structure defects . As can be seen from Figure l, the lubricating oil from the shaft end of the plug guide hole injection and then gradually fills the cavity . In practice , if there is no oiling special tools , lubricants only under its own weight is difficult detour through the guide wheel cavity , and the cavity gas emissions poor , oil is difficult to fill ; cavity and original design body oil-filled space is too small , resulting in a serious shortage of lubricant. In addition, the guide shaft and sleeve friction lubricants gap because there is no oil in the bearing track and not be able to produce tropical walk , resulting in bearing operating temperature, oil viscosity decreases , the lubricant film thickness decreases .

      Third, solutions
      3.1 improve processing quality in the processing , to ensure concentricity of the inner sleeve is in a predetermined range ∮ 0.025; guiding axles should meet the requirements of surface roughness of 1.6 X.

      3.2 to improve the structure
      ( A ) an increase in the welding of the hub member and the accumulator oil passage tanks, oil storage increases , so that the original fuel injection 150ml to 1182ml, lubricants improve the circulatory state ;

      ( 2 ) the restructuring of the original oiling tools. As shown in Figure 3 , the original oiler injection nozzle taper of 90 ° changed to 120 °, to ensure consistency with the guide hole in the axle stepped taper size. When refueling oiler nipple hole ladder with a beat , by the pressure of the lubricant oil through a circuitous path , into the oil reservoir chamber . Air is discharged from A ,