Experimental Research On The Friction And Wear Properties Of Rotary Tiller Blade

With the rapid development of agricultural economy, especially the promotion and widely used of modern mechanical products, rotary tiller plays a more and more important role in agricultural production. As the main working parts of rotary tiller, rotary tiller blade will generate drastic friction and impact with soil sand and so on, after reaching a certain degree, it will affect the work efficiency and service life. Therefore, the friction and wear properties of rotary tiller blade are particularly important, but the problems do not get deeper and better research so far, especially in the field of experimental research. Small piece of sample of rotary tiller dry-land blade and wet-land curved blade were chose as the studying object in this article, the friction and wear properties were systematic experimental study, and combined with the related theory and the experimental results, the service life was analyzed and evaluated, some measures of improving the service life were put forwarded, which are of great importance in proper evaluating the working performance of rotary tiller blades.Based on HSR-2M high-speed reciprocating friction and wear tester and other testing equipments, the effects of normal force, reciprocating velocity, reciprocating sliding distance, lubrication, roughness and temperature changes of the friction surface on the friction and wear properties of the two rotary tiller blades were studied, mainly includes the friction coefficient, wear volume loss, wear rate, wear contour, surface topography and wear mechanisms. By the experimental study, some main conclusions were obtained as follows:1. Friction coefficient: With the increasing of normal force and reciprocating velocity, the friction coefficients of two blades both decrease, and finally tended to be stable, but the stable value of wet-land curved blade was less than that of dry-land blade; roughness mainly affect the contact of friction pair, when the roughness is bigger, then the corresponding friction coefficient is also bigger.2. Wear volume loss: With the increasing of normal force, the wear volume loss of two blades both increase, and when the normal force is 70 N, it shows a more obvious increasing trend; with the increasing of reciprocating velocity, the wear volume loss of two blades both firstly decreases and then increases, but the reciprocating velocity of the turning point is different, which of dry-land blade and wet-land curved blade is 0.02 m/s and 0.023m/s; with the increasing of reciprocating sliding distance, the wear volume loss of two blades both increase, but increasing trend finally shows lower; with the increasing of roughness, the wear volume loss of two blades both approximately linearly increases.3. Wear rate: With the increasing of normal force, the wear rate of two blades both increase; during different ranges of reciprocating velocity, the variation trends of wear rate changing with reciprocating velocity of two blades are not completely the same. For dry-land blade, with the increasing of reciprocating velocity,wear rate firstly decreases, then increases slowly and finally increases rapidly during low velocity stage, the wear rate firstly increases rapidly, then increases slowly or essentially constant during medium velocity stage, the wear rate gradually increases during high velocity stage. For wet-land curved blade, with the increasing of reciprocating velocity, wear rate firstly decreases then increases during low velocity stage, wear rate gradually increases during medium velocity stage, the wear rate firstly increases slowly or essentially constant, then increases rapidly during high velocity stage. In terms of comprehensive, the optimal reciprocating velocity of dry-land blade under the experimental condition is 0.08m/s, for wet-land curved blade is 0.1m/s, the two blades are in a relatively stable wear stage.4. Wear mechanisms: For dry-land blade,it mainly shows abrasive wear under the experimental condition with low reciprocating velocity, low normal force and small reciprocating sliding distance, and with the increasing of test parameters, it shows more obvious phenomenon of abrasive wear, to a certain extent it is also accompanied with adhesive wear of material abrasion and transfer; for wet-land curved blade, it besides shows abrasive wear and adhesive wear those similar with dry-land blade, it even shows the phenomenon of pitting because of water lubrication that will generate extrusion to the local of sample.