The core hint: the cause analysis and improvement of the axle wear of the YTO T90 bulldozer: YTO T90 industrial bulldozer is a new product developed by our company in 1998. Because of its small tonnage and large thrust, it is especially adapted to the earthwork of the small and medium scale engineering in I ~ III soil, which has been welcomed by the vast number of users.
YTO T90 industrial bulldozer is a new product developed by our company in 1998. Because of its small tonnage and large thrust, it is especially adapted to the earthwork of small and medium sized I ~ III soil engineering, so it has been welcomed by the vast number of users.
However, in the early stage of listing, users appeared to be damaged after the use of a certain period of time, the damage of the steering wheel, the severe wear of the axle and the burning of the axle sleeve. To this end, our company launched a quality research, and found a solution.
First, the structure principle of the T90 bulldozer guide wheel is used to support the crawler and guide track winding, and its flange is stuck to the outer edge of the caterpillar track, preventing the lateral falling off, and tensioning the crawler by the tension buffer connected with it to ease the impact from the ground to the frame. Figure L is a diagram of its structure. The guide wheel is welded to the steel plate and its radial section is box shaped. The guide wheel is mounted on the guide wheel axle through the bimetal sleeve sliding bearing in the rim hole, and the two ends of the shaft are fixed on the left and right supports. The guide wheel and the left and right bracket adopt floating oil seal, and the floating oil seal and the O ring are pressed by the locking pin between the left and right supporting frames and the guide wheel shaft. Lubricating oil is added to the guide wheel to ensure lubrication and heat dissipation of the sliding bearing.
Two. The analysis of the cause of wear and tear is verified by inspection. It is caused by the deterioration of the lubrication state between the guiding axle and the bearing sleeve of the sliding bearing, which is caused by the transformation of the boundary lubrication to a part of dry friction. In normal work, there is a certain gap between the guide axle and the bearing sleeve of the sliding bearing, and the oil film exists, forming a liquid lubrication, and the resulting heat is small, and the lubricating oil is taken away to make the working temperature of the bearing in the normal state. If the lubrication state of the bearing sleeve and shaft deteriorates and forms part of the dry friction state, the friction power increases sharply and produces a lot of friction heat. When the temperature exceeds the melting point of the alloy surface, the surface of the sleeve begins to melt until it is completely burned.
The main factors leading to poor lubrication of steering wheel are:
(1) guide wheel double metal sleeve sliding bearing coaxiality 0.025 overproof. There will be a jump and shock in the track. The strong impact force is supported and transmitted through the sliding bearing. Therefore, the clearance between the sliding bearing and the shaft is uniform and the coaxiality of the bearing is required. If its geometric size is too poor, leading to the clearance between the wheel shaft and the axle sleeve too small or no clearance, the lubricant film thickness is not enough or even no lubricant film.
(2) guide the surface roughness of the wheel axle Ra1.6 over difference. There are many metal peaks on the surface of the shaft, and these metal peaks destroy the integrity and continuity of the lubricating oil film between the shaft and the journal bearing. When working, a large number of metal debris will be produced in the lubricating oil, which makes the surface roughness of the shaft and bearing increase, and the lubrication state becomes worse and worse, which causes the wear of the guide axle and the sliding bearing.
(3) there are defects in the original structure. As can be seen from Fig. L, lubricating oil is injected from the leading end of the wheel shaft end and then gradually fills the entire cavity. In actual operation, if there is no special oil injection tool, the lubricating oil is difficult to pass through the circuitous cavity in the guide wheel only under the action of its own gravity, and the exhaust gas in the cavity is not smooth, and the lubricating oil is difficult to fill up; and the original design cavity filling space is too small, causing the oil quantity to be seriously inadequate. In addition, the lubricating oil in the clearance between the wheel shaft and the axle sleeve can not walk in the friction tropical zone of the bearing because of no oil channel, resulting in the increase of the working temperature of the bearing, the decrease of the viscosity of the lubricating oil and the decrease of the thickness of the lubricating oil film.
Three. Measures to solve
3.1 to improve the processing quality in processing, the coaxiality of the shaft sleeve should be ensured within the specified range of 0.025; the surface roughness of the guide axle should be in accordance with the request of the Lord 1.6.
3.2 improve the structure
(1) increase the oil and storage tanks on the hub soldering parts, increase the oil storage volume, increase the oil injection volume from the original 150ml to 1182ml, and improve the circulation state of the lubricating oil.
(2) restructure the original oil injection tools. Change the taper of the oil injector from 90 degrees to 120 degrees, and ensure that the taper size of the step hole in the wheel shaft is consistent. When filling, the oil injector nozzle is pressed on the step hole, and the oil is injected into the oil storage cavity through the circuitous oil passage by pressure.
